WO2023048086A1 - Wavelength plate, optical system, and display device - Google Patents

Wavelength plate, optical system, and display device Download PDF

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Publication number
WO2023048086A1
WO2023048086A1 PCT/JP2022/034770 JP2022034770W WO2023048086A1 WO 2023048086 A1 WO2023048086 A1 WO 2023048086A1 JP 2022034770 W JP2022034770 W JP 2022034770W WO 2023048086 A1 WO2023048086 A1 WO 2023048086A1
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Prior art keywords
retardation layer
layer
retardation
liquid crystal
wave plate
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PCT/JP2022/034770
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French (fr)
Japanese (ja)
Inventor
康宏 池田
貴之 北尾
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Ａｇｃ株式会社
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Publication of WO2023048086A1 publication Critical patent/WO2023048086A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/02—Physical, chemical or physicochemical properties
    • B32B7/023—Optical properties
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/13363—Birefringent elements, e.g. for optical compensation
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1337—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F9/00—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B33/00—Electroluminescent light sources
    • H05B33/02—Details
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00

Definitions

  • the present disclosure relates to waveplates, optical systems, and display devices.
  • a wave plate which is an optical element that converts the polarization state of transmitted light, is known. Wave plates are used in various applications such as viewing angle compensation or antireflection in display devices such as liquid crystal displays or organic EL (Electro Luminescence) displays, or optical measurements. By converting incident light into circularly polarized light or linearly polarized light according to the purpose, improvement of display quality, observation of material properties, removal of background noise, etc. are performed.
  • a retardation film in which a plurality of optically anisotropic layers are laminated is known (see Patent Document 1, for example). Further, it includes a first liquid crystal layer and a second liquid crystal layer, and the angle of the slow axis of the first liquid crystal layer on the second liquid crystal layer side is the same as that of the second liquid crystal layer on the first liquid crystal layer side.
  • a configuration equal to the angle of the slow axis is disclosed (see, for example, Patent Document 2).
  • a wave plate is required to convert the polarization state of visible light incident on the wave plate over a wide range of incident angles and incident azimuth angles with high ellipticity.
  • visible light refers to light with a wavelength visible to the human eye.
  • Visible light is, for example, light having a wavelength in the range of 380 nm to 780 nm.
  • the incident angle is the angle formed by the direction of incidence of light on the wavelength plate and the normal to the boundary surface of the wavelength plate.
  • the incident azimuth angle is the angle formed by the azimuth of light incident on the wave plate and the reference azimuth within the boundary plane of the wave plate.
  • a boundary surface refers to a surface that includes the boundary between the wave plate and the atmosphere.
  • Ellipticity is the ratio of the length of the major axis to the length of the minor axis of elliptically polarized light, which is the state of polarization between circularly polarized light and linearly polarized light.
  • the ellipticity is 1 when the length of the major axis is equal to the length of the minor axis.
  • the ellipticity is an index representing whether the polarized light is close to circularly polarized light or linearly polarized light. The closer the ellipticity is to 1, the closer the polarization is to circular polarization, and the closer the ellipticity is to 0, the closer the polarization is to linear polarization.
  • Converting with a high ellipticity means converting incident linearly polarized light into elliptically polarized light with an ellipticity close to 1, or converting incident circularly polarized light into elliptically polarized light with an ellipticity close to 0.
  • One aspect of the present disclosure is a wave plate capable of converting the polarization state of light incident on the wave plate at a wide incident angle and incident azimuth angle with high ellipticity, an optical system including the wave plate, or a display including the optical system
  • the purpose is to provide an apparatus.
  • a wave plate includes a first retardation layer and a second retardation layer, linearly polarized light is incident from the first retardation layer side to the second retardation layer side
  • the layers include a first liquid crystal layer, the second retardation layer includes a second liquid crystal layer, and at least one of the first liquid crystal layer and the second liquid crystal layer extends in the thickness direction.
  • liquid crystal molecules are twisted and aligned, and in the three-dimensional coordinate system of the wave plate, the slow axis of the first retardation layer on the side of the second retardation layer and the second retardation layer and the slow axis on the side of the first retardation layer in is 10° or more.
  • a wave plate includes a first retardation layer and a second retardation layer, linearly polarized light is incident from the first retardation layer side to the second retardation layer side
  • the layer includes a first liquid crystal layer
  • the second retardation layer includes a second liquid crystal layer
  • the retardation R1 of the first retardation layer at a wavelength of 550 nm and the Each retardation R2 at a wavelength of 550 nm is 20 nm or more, and when R1 and R2 are compared, the larger thickness retardation RthA is positive.
  • a wave plate includes a first retardation layer, a second retardation layer, and a third retardation layer in this order, and linearly polarized light is incident from the first retardation layer side. to emit circularly polarized light from the third retardation layer side, or to emit circularly polarized light from the third retardation layer side and emit linearly polarized light from the first retardation layer side wherein the first retardation layer includes a first liquid crystal layer, the second retardation layer includes a second liquid crystal layer, and the third retardation layer includes a third Including a liquid crystal layer, the retardation R1 at a wavelength of 550 nm of the first retardation layer, the retardation R2 at a wavelength of 550 nm of the second retardation layer, and the retardation R3 at a wavelength of 550 nm of the third retardation layer are each It is 20 nm or more, and when R1, R2 and R3 are compared, the largest thickness retardation Rtha is positive.
  • a wavelength plate capable of converting the polarization state of light incident on the wavelength plate at a wide angle of incidence and azimuth angle with high ellipticity, an optical system including the wavelength plate, or an optical system It is possible to provide a display device equipped with
  • FIG. 3 is a plan view illustrating the configuration of a wave plate according to the embodiment;
  • FIG. FIG. 2 is a cross-sectional view of the first example taken along the II section line of FIG. 1;
  • FIG. 2 is a cross-sectional view of the second example taken along the II section line of FIG. 1; It is a figure which illustrates the conversion of the polarization state by the wavelength plate which concerns on embodiment.
  • FIG. 4 is a cross-sectional view illustrating a horizontally aligned liquid crystal layer;
  • FIG. 4 is a plan view illustrating a horizontally aligned liquid crystal layer;
  • FIG. 4 is a cross-sectional view illustrating a vertically aligned liquid crystal layer;
  • FIG. 4 is a cross-sectional view illustrating a twisted liquid crystal layer
  • 9 is a plan view illustrating the liquid crystal layer of FIG. 8 viewed from the light incident side
  • FIG. 9 is a plan view illustrating the liquid crystal layer of FIG. 8 viewed from the light exit side
  • FIG. 10B(A) is a perspective view showing an example of a transparent substrate and an alignment layer
  • FIG. 10B(B) is a perspective view showing an example of liquid crystal molecules aligned by the alignment layer shown in FIG. 10B(A).
  • FIG. 10C(A) is a microscopic sectional view
  • FIG. 10C(B) is a macroscopic sectional view showing an example of a configuration of a wave plate having a plurality of grooves; It is a figure explaining the wavelength dispersion in a liquid crystal layer.
  • FIG. 4 is a diagram illustrating an angle formed between a slow axis of a first retardation layer on the side of the second retardation layer and a slow axis of the second retardation layer on the side of the first retardation layer. It is a figure which illustrates the in-plane retardation of the 1st retardation layer which concerns on embodiment. It is a figure explaining the incident angle and incident azimuth angle of the light which injects into a wavelength plate. It is a figure explaining the ellipticity of polarized light.
  • FIG. 4 is a diagram illustrating an angle formed between a slow axis of a first retardation layer on the side of the second retardation layer and a slow axis of the second retardation layer on the side of the first retardation layer. It is a figure which
  • FIG. 4 is a diagram illustrating changes in ellipticity with wavelength; 17 is a diagram extracting and showing the range of ⁇ in FIG. 16;
  • FIG. 3 is a first schematic diagram showing three-dimensional intersection angles of slow axis azimuth angles of Example 1.
  • FIG. 3 is a second schematic diagram showing a three-dimensional intersection angle of slow axis azimuth angles of Example 1.
  • FIG. 4 is a contour diagram of ellipticity in Example 1.
  • FIG. It is a contour figure of the ellipticity in a comparative example.
  • 4 is a diagram illustrating changes in ellipticity according to wavelength in Example 1.
  • FIG. It is a figure which illustrates the change of the ellipticity according to the wavelength in a comparative example.
  • directions may be indicated by the X-axis, Y-axis, and Z-axis, but the X-direction along the X-axis indicates a predetermined direction within the interface between the wave plate according to the embodiment and the atmosphere.
  • the Y-direction along the Y-axis indicates a direction perpendicular to the X-direction within the boundary plane, and the Z-direction along the Z-axis indicates a direction perpendicular to the boundary plane.
  • a planar view in the terminology of the embodiment means viewing the wave plate from the Z direction.
  • a plan view is a view of the wave plate viewed from the Z direction.
  • these do not limit the orientation of the wave plate when it is used, and the orientation of the wave plate is arbitrary.
  • FIG. 1 to 3 are diagrams illustrating the configuration of the wave plate 1 according to the embodiment.
  • 1 is a plan view of the wave plate 1
  • FIG. 2 is a cross-sectional view of the first example along the II section line of FIG. 1
  • FIG. 3 is a cross-sectional view of the second example along the II section line of FIG. be.
  • the wave plate 1 is a plate-like member having a substantially square shape in plan view. As shown in FIG. 2 , the wave plate 1 includes a first retardation layer 11 and a second retardation layer 12 . In other words, the wave plate 1 is a laminated wave plate in which the first retardation layer 11 and the second retardation layer 12 are laminated.
  • Each of the first retardation layer 11 and the second retardation layer 12 gives a phase difference to the light incident through the boundary surface 10 and emits the light.
  • the first retardation layer 11 and the second retardation layer 12 are the surface of the first retardation layer 11 on the side of the second retardation layer 12 and the first retardation layer 12 of the second retardation layer 12.
  • the surface on the side of the layer 11 is arranged so as to be in contact with each other.
  • the wave plate 1 may further include a third retardation layer 13.
  • the wave plate 1 may be a laminated wave plate in which the first retardation layer 11, the second retardation layer 12, and the third retardation layer 13 are laminated.
  • the third retardation layer 13 receives the light emitted from the second retardation layer 12, gives it a phase difference, and emits it.
  • the third retardation layer 13 has a surface of the second retardation layer 12 on the side of the third retardation layer 13 and a surface of the third retardation layer 13 on the side of the second retardation layer 12. They are arranged to face and touch each other.
  • the first retardation layer 11, the second retardation layer 12, and the third retardation layer 13 are each translucent to visible light.
  • the first retardation layer 11, the second retardation layer 12, and the third retardation layer 13 each have translucency in the wavelength range from 300 nm to 2000 nm, more preferably from 380 nm. It has translucency in the wavelength range of 1000 nm.
  • Having translucency means having a transmittance of 50% or more, preferably 80% or more, in a wavelength range of 400 nm to 800 nm.
  • the transmittance can be measured, for example, with an ultraviolet-visible spectrophotometer (product name: UH-4150, manufactured by Hitachi High-Tech Science Co., Ltd.).
  • the wave plate 1 having a substantially square shape in plan view is exemplified, but it is not limited to this.
  • the wave plate 1 may have various planar shapes such as a rectangular shape, a circular shape, an elliptical shape, or a polygonal shape.
  • FIG. 4A and 4B are diagrams illustrating conversion of the polarization state by the wave plate 1.
  • FIG. The wavelength plate 1 of FIG. 4 has, for example, the configuration shown in FIG. 2, and the linearly polarized light P1 is incident from the first retardation layer 11 side and the circularly polarized light P2 is emitted from the second retardation layer 12 side.
  • the linearly polarized light P1 is light traveling in the Z direction.
  • Linearly polarized light refers to light whose electric field oscillates in a predetermined direction.
  • Circularly polarized light refers to light whose vibration direction of an electric field rotates in a plane perpendicular to the traveling direction of light and whose amplitude is constant regardless of the direction of vibration of the electric field.
  • the locus of the electric field seen from the traveling direction of light draws a straight line with linearly polarized light and a circle with circularly polarized light.
  • the electric field of the linearly polarized light P1 oscillates in a plane substantially parallel to the boundary surface 10 in a direction inclined by the polarization axis azimuth angle ⁇ 0 with respect to the X axis.
  • the polarization axis azimuth angle ⁇ 0 is, for example, 45°.
  • the linearly polarized light P1 can be incident on the wavelength plate 1 at a predetermined polarization axis azimuth angle ⁇ 0 with respect to the wave plate 1, the polarization axis azimuth angle ⁇ 0 with respect to the X axis is not limited to 45°.
  • the electric field component P1X is the electric field oscillation component of the linearly polarized light P1 in the X direction.
  • the electric field component P1Y is an electric field vibration component in the Y direction of the linearly polarized light P1.
  • the wave plate 1 delays the phase of, for example, the electric field component P1Y of the incident linearly polarized light P1 with respect to the electric field component P1X, and gives the electric field component P1Y a phase difference with respect to the electric field component P1X.
  • the wave plate 1 converts the linearly polarized light P1 into circularly polarized light P2 by giving a phase difference corresponding to approximately 1/4 of the wavelength of the linearly polarized light P1 to the incident linearly polarized light P1. do.
  • the wavelength plate 1 exemplifies a configuration in which the linearly polarized light P1 is incident from the first retardation layer 11 side and the circularly polarized light P2 is emitted from the second retardation layer 12 side, but it is limited to this. not a thing
  • the wave plate 1 can also enter the circularly polarized light P2 from the second retardation layer 12 side and emit the linearly polarized light P1 from the first retardation layer 11 side.
  • the configuration shown in FIG. 2 is illustrated as the wave plate 1 in FIG. A layer 13 (see Figure 3).
  • the wave plate 1 including the third retardation layer 13 the first retardation layer 11, the second retardation layer 12, and the third retardation layer 13 are arranged in this order from the side on which the linearly polarized light P1 is incident. Laminated.
  • the wave plate 1 including the third retardation layer 13 receives circularly polarized light, the first retardation layer 11, the second retardation layer 12, and the third 3 retardation layers 13 are laminated in this order.
  • the first retardation layer 11 includes a first liquid crystal layer
  • the second retardation layer 12 includes a second liquid crystal layer
  • the third retardation layer 13 includes a third liquid crystal layer.
  • Each of the first retardation layer 11, the second retardation layer 12, and the third retardation layer 13 is a horizontally aligned liquid crystal layer, a vertically aligned liquid crystal layer, or a twisted liquid crystal layer.
  • the alignment of the liquid crystal layer means that the long axes of the rod-like liquid crystal molecules contained in the liquid crystal layer are oriented in a predetermined direction.
  • FIG. 5 and 6 are diagrams illustrating horizontally aligned liquid crystal layers. 5 is a sectional view, and FIG. 6 is a plan view.
  • FIG. 7 is a cross-sectional view illustrating a vertically aligned liquid crystal layer.
  • 8, 9 and 10A are diagrams illustrating twisted liquid crystal layers. 8 is a cross-sectional view, FIG. 9 is a plan view of the liquid crystal layer of FIG. 8 viewed from the light incident side, and FIG. 10A is a plan view of the liquid crystal layer of FIG. 8 viewed from the light exit side.
  • the first liquid crystal layer included in the first retardation layer 11 will be described below as an example.
  • the first retardation layer 11 includes an incident-side substrate 111, an incident-side alignment layer 112, an exit-side substrate 113, an exit-side alignment layer 114, and a first liquid crystal layer. 110;
  • the incident-side alignment layer 112 is provided on the incident-side substrate 111 .
  • the exit-side alignment layer 114 is provided on the exit-side substrate 113 .
  • a first liquid crystal layer 110 is provided between an entrance-side alignment layer 112 and an exit-side alignment layer 114 .
  • the entrance-side substrate 111 and the exit-side substrate 113 each contain a material such as glass or resin that transmits visible light incident on the wavelength plate 1 .
  • the incident-side alignment layer 112 and the exit-side alignment layer 114 are provided on the surfaces of the incident-side substrate 111 and the exit-side substrate 113, respectively, in order to control the alignment of the liquid crystal molecules 115 contained in the first liquid crystal layer 110. It has fine grooves.
  • the incident-side alignment layer 112 and the exit-side alignment layer 114 include an organic thin film such as polyimide, an inorganic deposited film, a film having a minute groove structure, or the like.
  • the liquid crystal molecules 115 are aligned in a horizontal direction substantially parallel to the interface 10, as shown in FIG. Further, as shown in FIG. 6, the slow axis 116 of the liquid crystal molecule 115 is oriented at the slow axis azimuth angle ⁇ c with respect to the X axis in a plane (for example, the XY plane) substantially parallel to the boundary surface 10. Tilt and orient.
  • the slow axis is the axis in which the traveling speed of light slows down and the phase lags when light propagates through a material with birefringence. Light whose electric field oscillates along the slow axis slows down.
  • the liquid crystal molecules 115 are aligned in a direction substantially perpendicular to the interface 10 (for example, the Z-axis direction).
  • the orientation of the liquid crystal molecules 115 changes so as to be twisted from the entrance side substrate 111 toward the exit side substrate 113. As shown in FIG. In other words, the liquid crystal molecules 115 are twisted and oriented in the thickness direction of the liquid crystal layer.
  • the liquid crystal molecules 115 include incident-side liquid crystal molecules 115s and exit-side liquid crystal molecules 115e.
  • the incident-side liquid crystal molecules 115 s are liquid crystal molecules present at the end of the liquid crystal molecules 115 on the side where the first retardation layer 11 is incident on light.
  • the output-side liquid crystal molecules 115e are liquid crystal molecules present at the end of the liquid crystal molecules 115 on the side from which the first retardation layer 11 emits light.
  • the incident-side slow axes 116s of the incident-side liquid crystal molecules 115s are oriented at a slow axis azimuth angle ⁇ c_s with respect to the X-axis in a plane substantially parallel to the boundary surface 10.
  • the output-side slow axes 116e of the output-side liquid crystal molecules 115e are aligned in a plane substantially parallel to the boundary surface 10, tilting in the direction of the slow axis azimuth ⁇ c_e with respect to the X-axis. .
  • the first retardation layer 11 includes both the incident-side alignment layer 112 and the exit-side alignment layer 114, but it is not limited to this.
  • the first retardation layer 11 may include only one of the incident-side alignment layer 112 and the exit-side alignment layer 114 .
  • the first retardation layer 11 may have a configuration that does not include either the incident-side alignment layer 112 or the exit-side alignment layer 114 .
  • the first retardation layer 11 includes both the incident-side substrate 111 and the exit-side substrate 113
  • the first retardation layer 11 is either the incident-side substrate 111 or the exit-side substrate 113. A configuration including only one of them may be employed.
  • the second retardation layer 12 has the same configuration as the first retardation layer 11 , but differs in that it includes a second liquid crystal layer 120 instead of the first liquid crystal layer 110 .
  • the third retardation layer 13 also has the same configuration as the first retardation layer 11 , but differs in that it includes a third liquid crystal layer 130 instead of the first liquid crystal layer 110 .
  • the second liquid crystal layer 120 and the third liquid crystal layer 130 each comprise liquid crystal molecules 115 .
  • the reference numerals of the second retardation layer 12 and the third retardation layer 13 are written together with the reference numerals of the first retardation layer 11 in brackets.
  • the reference numerals of the second liquid crystal layer 120 and the third liquid crystal layer 130 are written together with the reference numerals of the first liquid crystal layer 110 in brackets.
  • the second retardation layer 12 does not have to have the same configuration as the first retardation layer 11 as long as it includes the second liquid crystal layer 120 .
  • the third retardation layer 13 does not have to have the same configuration as the first retardation layer 11 as long as the third liquid crystal layer 130 is provided.
  • the first retardation layer 11, the second retardation layer 12, and the third retardation layer 13 are each cured by being irradiated with ultraviolet rays in a state in which the liquid crystal molecules 115 are aligned in a predetermined direction.
  • Wave plate 1 is fabricated by laminating cured layers.
  • the alignment layers such as the incident-side alignment layer 112 and the exit-side alignment layer 114 in the wavelength plate 1 may have a plurality of grooves on the surface in contact with the liquid crystal layer such as the first liquid crystal layer 110 .
  • 10B(A) is a perspective view showing an example of the transparent substrate 4 and the alignment layer 5
  • FIG. 10B(B) is an example of liquid crystal molecules 61 aligned by the alignment layer 5 shown in FIG. 10B(A). It is a perspective view showing the.
  • FIG. 10C is a diagram showing an example of the configuration of a wavelength plate 1a having a plurality of grooves
  • FIG. 10C(A) is a microscopic cross-sectional view
  • FIG. 10C(B) is a macroscopic cross-sectional view. is.
  • the transparent base material 4 corresponds to an example of the substrate, and the surfaces of the transparent base material 4 along the X direction and the Y direction in FIGS. 10B and 10C correspond to an example of the surface of the substrate.
  • the plurality of grooves are parallel to each other when viewed in the Z-axis direction.
  • a plurality of grooves are formed by, for example, an imprint method after applying the resin composition.
  • a plurality of grooves are formed, for example, in a stripe pattern.
  • the direction parallel to the ground is the X axis as well as the Z axis.
  • the direction perpendicular to the ground is the Y-axis direction.
  • the thickness T1 of the transparent substrate 4 is, for example, 0.01 mm to 0.3 mm, preferably 0.02 mm to 0.1 mm, more preferably 0.03 mm to 0.09 mm. If T1 is within the above range, both bending workability and handleability can be achieved.
  • the alignment layer 5 orients the liquid crystal molecules of the liquid crystal layer 6 .
  • a plurality of parallel grooves 51 are formed on the surface 121 of the alignment layer 5 in contact with the liquid crystal layer 6 .
  • the plurality of grooves 51 are formed, for example, in a stripe pattern.
  • the longitudinal direction of the groove 51 is the X-axis direction
  • the width direction of the groove 51 is the Y-axis direction.
  • the parallelism of the grooves 51 is, for example, 0° to 5°, preferably 0° to 1°.
  • the parallelism of the grooves 51 is the maximum value of the angle formed by two adjacent grooves 51 when viewed in the Z-axis direction. The closer the angle between two adjacent grooves 51 to 0°, the better the parallelism.
  • the depth D of the groove 51 is, for example, 3 nm to 500 nm, preferably 5 nm to 300 nm, more preferably 10 nm to 150 nm.
  • D is 3 nm or more, the alignment regulating force is large, and the liquid crystal molecules are easily aligned.
  • D is 500 nm or less, the transferability of the concave-convex pattern of the mold is good.
  • D is 500 nm or less, diffracted light is less likely to occur.
  • the depth of the groove 51 at the center of the retardation layer may be deeper or shallower than the depth of the groove 51 at the outer periphery of the retardation layer.
  • the depth D of the grooves 51 is adjusted, for example, by the concave-convex pattern of the mold used in the imprint method.
  • the depth D of the groove 51 can also be adjusted by partially ashing the surface of the alignment layer 5 .
  • the depth D of the grooves 51 at the center of the retardation layer is deeper than the depth D of the grooves 51 at the periphery of the retardation layer.
  • the depth D of the groove 51 increases continuously or stepwise from the periphery to the center of the retardation layer. Therefore, it is possible to suppress the retardation from shifting concentrically, and it is possible to suppress the color tone from shifting concentrically.
  • This depth distribution can be appropriately changed depending on whether the curved surface is concave or convex, the shape of the curved surface, and the like. Moreover, it can be created by the above-described imprint method or the like.
  • the orientation of the grooves 51 can also be appropriately changed between the center and the outer periphery, as well as for each in-plane location. For example, by tilting the grooves 51 on the outer periphery with respect to the center, the direction of polarized light incident on the curved surface can be corrected. This can also be produced by the imprint method described above.
  • the opening width W of the groove 51 is, for example, 5 nm to 800 nm, preferably 20 nm to 300 nm, more preferably 30 nm to 150 nm.
  • the pitch p of the grooves 51 is, for example, 10 nm to 600 nm, preferably 50 nm to 300 nm, more preferably 80 nm to 200 nm.
  • p is 600 nm or less
  • the alignment control force is large and the liquid crystal molecules are easily aligned.
  • p is 300 nm or less, diffracted light is less likely to occur.
  • p is 10 nm or more, it is easy to form the uneven pattern of the mold.
  • the opening width W of the groove 51 is, for example, 5 nm to 500 nm, preferably 20 nm to 200 nm, more preferably 30 nm to 150 nm.
  • the difference between the pitch p and the opening width W (p ⁇ W: p>W) is the interval between the grooves 51 (the width of the protrusion separating the two grooves 51).
  • a cross section perpendicular to the longitudinal direction (X-axis direction) of the groove 51 may be rectangular, triangular, or trapezoidal.
  • the groove 51 becomes wider as the depth becomes shallower. In this case, it is easy to peel off the mold used in the imprint method.
  • Materials for forming the groove structure include, for example, energy curable resins such as photocurable resins and thermosetting resins.
  • photocurable resins are preferred because they are excellent in workability, heat resistance and durability.
  • the photocurable resin composition is, for example, a composition containing a monomer, a photopolymerization initiator, a solvent, and optional additives (eg, surfactant, polymerization inhibitor).
  • the thickness T2 of the alignment layer 5 is, for example, 1 nm to 20 ⁇ m, preferably 50 nm to 10 ⁇ m, more preferably 100 nm to 5 ⁇ m.
  • the thickness T2 of the orientation layer 5 is measured in the normal direction at each point on the surface 4a of the transparent substrate 4 on which the orientation layer 5 is formed.
  • the thickness T2 of the alignment layer 5 herein means the distance between the bottom of the grooves 51 and the surface 4 a of the transparent substrate 4 . If the thickness T2 of the orientation layer 5 is 20 ⁇ m or less, workability is good.
  • the glass transition point Tg_al of the alignment layer 5 is, for example, 40°C to 200°C, preferably 50°C to 160°C, more preferably 70°C to 150°C. If Tg_al is within the above range, bending workability is good.
  • the glass transition point of the alignment layer 5 is measured, for example, by thermal mechanical analysis (TMA Q400) of TA Instruments Japan.
  • the thickness T3 of the liquid crystal layer 6 is determined based on the wavelength of light, the phase difference, and ⁇ n as described above, and is not particularly limited, but is, for example, 0.3 ⁇ m to 30 ⁇ m, preferably 0.5 ⁇ m to 20 ⁇ m. and more preferably 0.8 ⁇ m to 10 ⁇ m.
  • T3 is 0.3 ⁇ m or more, a desired phase difference can be easily obtained. Further, when T3 is 30 ⁇ m or less, the liquid crystal molecules are easily aligned.
  • the liquid crystal layer 6 is not limited to a 1/4 wavelength plate, and may have any retardation such as a 1/2 wavelength plate as long as it meets the purpose. Moreover, the liquid crystal layer 6 is not limited to a retardation layer that shifts the phase between two orthogonal linearly polarized light components, and may be a compensation layer using a biaxial retardation plate or the like. The compensation layer, for example, corrects the phase difference that occurs at different viewing angles of the liquid crystal display and improves the contrast of the screen within a given viewing angle.
  • the thickness T3 of the liquid crystal layer 6 is measured in the normal direction at each point on the surface 4a of the transparent substrate 4.
  • the thickness T3 of the liquid crystal layer 6 herein means the distance between the bottom of the grooves 51 and the surface of the liquid crystal layer 6 opposite the alignment layer 5 .
  • the glass transition point Tg_a of the liquid crystal layer 6 is, for example, 50°C to 200°C, preferably 80°C to 180°C. If Tg_a is within the above range, bending workability is good.
  • the glass transition point Tg_a of the liquid crystal layer 6 is measured by TMA, for example.
  • the thickness T4 of the wave plate 1 is not particularly limited, it is, for example, 0.011 mm to 0.301 mm, preferably 0.021 mm to 0.101 mm, and more preferably 0.031 mm to 0.091 mm.
  • the thickness T4 of the wave plate 1 is measured in the normal direction at each point on the surface 4a of the transparent substrate 4. As shown in FIG.
  • the wave plate 1 may include a liquid crystal layer having a slow axis direction different from that of the liquid crystal layer 6, and may further include an alignment layer for aligning the liquid crystal molecules of the liquid crystal layer. That is, the wave plate 1 may be a broadband retardation plate.
  • the number of liquid crystal layers included in wave plate 1 may be two or more.
  • a wave plate 1a having a plurality of grooves parallel to each other when viewed in the Z-axis direction on the surface where the alignment layer contacts the liquid crystal layer can have the following configuration (see FIGS. 10B and 10C). That is, the wave plate 1a includes a first retardation layer 11, a second retardation layer 12, a third retardation layer 13, and a transparent substrate 4 that supports them.
  • the first retardation layer 11 includes a first liquid crystal layer 110 .
  • the second retardation layer 12 includes a second liquid crystal layer 120 .
  • the third retardation layer 13 includes a third liquid crystal layer 130 .
  • the liquid crystal molecules 61 are oriented parallel to the substrate surface of the transparent base material 4 .
  • the liquid crystal molecules 61 are twisted and aligned in the thickness direction.
  • the liquid crystal molecules of the second liquid crystal layer 120 are vertically aligned in the thickness direction.
  • Each of the first retardation layer and the third retardation layer includes an alignment layer 5 (114, 134) composed of fine one-dimensional lattice-like grooves.
  • the first retardation layer 11, the second retardation layer 12, and the third retardation layer 13 are laminated in this order from the linearly polarized incident side.
  • FIG. 10C(B) is an image diagram, and the alignment direction of the liquid crystal molecules in the liquid crystal layer and the direction of the grooves in the alignment layer are not limited to this.
  • the wave plate 1a may have the following configuration.
  • An adhesive layer 201 may be provided between the third retardation layer 13 and the second retardation layer 12 .
  • the adhesive layer is formed of OCA, ultraviolet curable resin, or the like.
  • the second retardation layer 12 may have an orientation layer.
  • the alignment layer may be provided with an incident-side alignment layer and an exit-side alignment layer as shown in FIG. .
  • the wave plate 1a may have the following configuration. That is, when the liquid crystal molecules 115 (61) are oriented parallel to the transparent base material 4, the liquid crystal molecules 115 (61) are oriented parallel to the normal to the transparent base material 4.
  • the tilt angle defined as 90° is 0° or more and less than 2°.
  • the twist directions of the liquid crystal molecules 115 (61) of the first liquid crystal layer 110 and the third liquid crystal layer 130 are the same, and the first liquid crystal layer 110, the second liquid crystal layer 120, and the third liquid crystal layer 130 Both are composed of positively dispersed liquid crystal molecules 115 (61).
  • the angle formed by the slow axis of the first retardation layer 11 on the side of the third retardation layer 13 and the slow axis of the second retardation layer 12 is 90°.
  • the angle formed by the slow axis of the third retardation layer 13 on the first retardation layer 11 side and the slow axis of the second retardation layer 12 is 90°.
  • the slow axis of the third retardation layer 13 on the first retardation layer 11 side and the third retardation layer 13 side of the first retardation layer 11 The angle formed with the slow axis is greater than 0° and less than 2°.
  • the three-dimensional coordinate system of the transparent base material 4 is a coordinate system defined by a total of three directions: the thickness direction of the transparent base material 4 and two orthogonal directions in a plane perpendicular to the thickness direction. means.
  • the wave plate 1a has an in-plane retardation of 280 nm or more and 300 nm or less at a wavelength of 550 nm of the first retardation layer 11 when the film thickness does not change during molding, and the wavelength of the second retardation layer 12 is 550 nm. is 15 nm or less, and the in-plane retardation of the third retardation layer 13 at a wavelength of 550 nm is 130 nm or more and 150 nm or less.
  • the in-plane retardation of the first retardation layer 11 at a wavelength of 550 nm is 310 nm or more and 335 nm or less
  • the second retardation layer 12 has a wavelength of 550 nm. is 17 nm or less
  • the in-plane retardation of the third retardation layer 13 at a wavelength of 550 nm is 140 nm or more and 17 nm or less.
  • Rth of the first retardation layer 11 and the third retardation layer 13 is positive.
  • the Rth of the second retardation layer 12 is negative, preferably -150 to -80 nm.
  • the wave plate 1 a may include a three-dimensional structure 301 .
  • the three-dimensional structure 301 may have curved surfaces.
  • the thickness of the transparent substrate 4 at the position 10 mm from the center of the three-dimensional structure 301 is 1.0 mm of the thickness of the transparent substrate 4 at the center of the three-dimensional structure 301 . It can be 0 times or more and 1.2 times or less.
  • the thickness of the transparent base material 4 at the position 13 mm from the center of the three-dimensional structure 301 is 1.0 times or more the thickness of the transparent base material 4 at the center of the three-dimensional structure 301 and 1.2 times. It can also be doubled or less.
  • the thickness of the transparent substrate 4 at a position 15 mm from the center of the three-dimensional structure 301 should be 1.0 times or more and 1.2 times or less than the thickness of the transparent substrate 4 at the center of the three-dimensional structure 301. can also
  • the wave plate 1a may have the following configuration.
  • the first retardation layer may have one or more of the incident-side substrate, the incident-side orientation layer, the exit-side orientation layer, and the exit-side substrate shown in FIG. 5 and the like.
  • the third retardation layer may have one or more of the incident-side substrate, the incident-side alignment layer, the exit-side alignment layer, and the exit-side substrate shown in FIG. 5 and the like.
  • the second retardation layer may have one or more of the incident-side substrate, the incident-side alignment layer, the exit-side alignment layer, and the exit-side substrate shown in FIG. 5 and the like.
  • the wave plate 1 will be described below, the wave plate 1 can be replaced with the wave plate 1a.
  • FIG. 11 is a diagram illustrating an example of the wavelength dispersion of the liquid crystal layer included in the wavelength plate 1.
  • the horizontal axis indicates the wavelength ⁇ of light incident on the wavelength plate 1
  • the vertical axis indicates the retardation R.
  • Solid line 53 represents inverse dispersion and dashed line 52 represents positive dispersion.
  • Reverse dispersion refers to the property that the longer the wavelength, the larger the retardation.
  • Positive dispersion means the property that the shorter the wavelength, the larger the retardation.
  • the material constituting the liquid crystal layer By determining the material constituting the liquid crystal layer, it is determined whether the liquid crystal layer has reverse dispersion or positive dispersion, and the property indicating the relationship between the wavelength ⁇ and the retardation R is determined.
  • each retardation layer In the wavelength plate 1 according to the present embodiment, the above-described horizontally aligned, vertically aligned, or twisted liquid crystal layer, or a liquid crystal layer having normal dispersion or reverse dispersion is used to form the first retardation layer 11, the second , the retardation layer 12 and the third retardation layer 13 are respectively formed.
  • At least one of the first liquid crystal layer 110 included in the first retardation layer 11 and the second liquid crystal layer 120 included in the second retardation layer 12 has liquid crystals in the thickness direction. Molecules 115 are twisted and oriented. An output-side slow axis 116e on the side of the second retardation layer 12 in the first retardation layer 11, and an incident-side slow axis 116s on the side of the first retardation layer 11 in the second retardation layer 12, is 10° or more.
  • the slow axis azimuth angle ⁇ c means an angle formed by the slow axis three-dimensionally.
  • the slow axis azimuth angle ⁇ c is preferably 13° or more, more preferably 15° or more.
  • the slow axis azimuth angle ⁇ c may be 20° or more, 50° or more, or 90°.
  • the retardation is the difference (ne- no) and the layer thickness t, and is represented by (ne-no) x t.
  • the retardation R1 of the first retardation layer 11 is represented by (n1e-n1?) x t1.
  • n1e be the refractive index of the first retardation layer 11 for light whose electric field oscillates along the slow axis.
  • n1o be the refractive index for light whose electric field oscillates along the direction perpendicular to the slow axis of the first retardation layer 11 .
  • t1 be the thickness of the first retardation layer 11 .
  • the retardation R2 of the second retardation layer 12 is represented by (n2e-n2?) x t2.
  • n2e be the refractive index of the second retardation layer 12 for light whose electric field oscillates along the slow axis.
  • n2o be the refractive index for light whose electric field oscillates along the direction orthogonal to the slow axis of the second retardation layer 12 .
  • t2 be the thickness of the second retardation layer 12 .
  • the retardation R3 of the third retardation layer 13 is represented by (n3e-n3?) x t3.
  • n3e be the refractive index of the third retardation layer 13 for light whose electric field oscillates along the slow axis.
  • n3o be the refractive index for light whose electric field oscillates along the direction perpendicular to the slow axis of the third retardation layer 13 .
  • t3 be the thickness of the third retardation layer 13 .
  • the in-plane retardation Re1 of the first retardation layer 11 is represented by the absolute value of (n1x ⁇ n1y) ⁇ t1.
  • n1x and n1y be refractive indices in directions parallel to the surface of the first retardation layer 11 (for example, the XY plane in FIGS. 2 and 3) and perpendicular to each other.
  • n1z be the refractive index in the direction perpendicular to the surface of the first retardation layer 11 .
  • t1 be the thickness of the first retardation layer 11 .
  • the in-plane retardation Re2 of the second retardation layer 12 is represented by the absolute value of (n2x ⁇ n2y) ⁇ t2.
  • n2x and n2y be refractive indices in directions parallel to the surface of the second retardation layer 12 (for example, the XY plane in FIGS. 2 and 3) and perpendicular to each other.
  • n2z be the refractive index in the direction perpendicular to the surface of the second retardation layer 12 .
  • t2 be the thickness of the second retardation layer 12 .
  • the in-plane retardation Re3 of the third retardation layer 13 is represented by the absolute value of (n3x ⁇ n3y) ⁇ t3.
  • n3x and n3y be refractive indices in directions parallel to the surface of the third retardation layer 13 (for example, the XY plane in FIGS. 2 and 3) and perpendicular to each other.
  • n3z be the refractive index in the direction perpendicular to the surface of the third retardation layer 13 .
  • t3 be the thickness of the third retardation layer 13 .
  • the x-direction and y-direction of the refractive index are determined so that nx and ny are equal to the direction of the extraordinary refractive index ne or the direction of the ordinary refractive index no of the liquid crystal.
  • nx ne
  • the wave plate 1 has a two-layer structure having a first retardation layer 11 and a second retardation layer 12 .
  • a layer having a large in-plane retardation (Re1, Re2) is called an A layer
  • a layer having a small in-plane retardation (Re1, Re2) is called a B layer.
  • ReA be the in-plane retardation of the A layer
  • ReB be the in-plane retardation of the B layer.
  • the thickness direction retardation RthA of the A layer is represented by the following equation.
  • RthA ((nAx + nAy)/2-nAz) x tA
  • nAx represents the refractive index of the A layer in the X-axis direction at a wavelength of 550 nm.
  • nAy represents the refractive index of the A layer in the Y-axis direction at a wavelength of 550 nm.
  • nAz represents the refractive index of the A layer in the Z-axis direction at a wavelength of 550 nm.
  • tA represents the thickness of the A layer.
  • the thickness direction retardation RthB of the B layer is expressed by the following equation.
  • RthB ((nBx+nBy)/2 ⁇ nBz) ⁇ tB
  • nBx represents the refractive index of the B layer in the X-axis direction at a wavelength of 550 nm.
  • nBy represents the refractive index of the B layer in the Y-axis direction at a wavelength of 550 nm.
  • nBz represents the refractive index of the B layer in the Z-axis direction at a wavelength of 550 nm.
  • tB represents the thickness of the B layer.
  • Wave plate 1 has first retardation layer 11 , second retardation layer 12 and third retardation layer 13 .
  • the in-plane retardation (Re1 to Re3) is a layer, b layer, and c layer in descending order.
  • Rea be the in-plane retardation of the a layer
  • Reb be the in-plane retardation of the b layer
  • Rec be the in-plane retardation of the c layer.
  • the retardation Rtha in the thickness direction of the a layer is expressed by the following equation.
  • Rtha ((nax+nay)/2 ⁇ naz) ⁇ ta
  • nax represents the refractive index of the a layer in the X-axis direction at a wavelength of 550 nm.
  • nay represents the refractive index of the a layer in the Y-axis direction at a wavelength of 550 nm.
  • Feli represents the refractive index of the a layer in the Z-axis direction at a wavelength of 550 nm.
  • ta represents the thickness of the a layer.
  • the retardation Rthb in the thickness direction of the b layer is expressed by the following equation.
  • Rthb ((nbx+nby)/2-nbz) ⁇ tb
  • nbx represents the refractive index of the b layer in the X-axis direction at a wavelength of 550 nm.
  • nby represents the refractive index of the b layer in the Y-axis direction at a wavelength of 550 nm.
  • nbz represents the refractive index of the b layer in the Z-axis direction at a wavelength of 550 nm.
  • tb represents the thickness of the b layer.
  • the retardation Rthc in the thickness direction of the c layer is expressed by the following equation.
  • Rthc ((ncx+ncy)/2 ⁇ ncz) ⁇ tc
  • ncx represents the refractive index of the c layer in the X-axis direction at a wavelength of 550 nm.
  • ncy represents the refractive index of the c layer in the Y-axis direction at a wavelength of 550 nm.
  • ncz represents the refractive index of the c layer in the Z-axis direction at a wavelength of 550 nm.
  • tc represents the thickness of the c layer.
  • the in-plane retardations ReA and ReB are preferably ReA ⁇ ReB-50 (nm), ReA>ReB+50 (nm), and ReB>50 (nm).
  • ReB is preferably 70 nm or more, more preferably 90 nm or more.
  • In-plane retardation Rea and in-plane retardation Reb are preferably Rea ⁇ Reb ⁇ 50 (nm), Rea>Reb+50 (nm), and Reb>50 nm.
  • Reb is preferably 70 nm or more, more preferably 90 nm or more.
  • the wave plate 1 includes the first retardation layer 11 and the second retardation layer 12, and the linearly polarized light is incident from the first retardation layer 11 side and from the second retardation layer 12 side Circularly polarized light is emitted, or circularly polarized light is incident from the second retardation layer 12 side and linearly polarized light is emitted from the first retardation layer 11 side.
  • the first retardation layer 11 includes a first liquid crystal layer 110 and the second retardation layer 12 includes a second liquid crystal layer 120 .
  • the retardation R1 of the first retardation layer 11 and the retardation R2 of the second retardation layer 12 are each 20 nm or more, and when comparing R1 and R2, the retardation is larger in the thickness direction of the retardation layer has a positive retardation RthA.
  • the wave plate 1 particularly includes a first retardation layer 11, a second retardation layer 12, and a third retardation layer 13 in this order, and linearly polarized light is incident from the first retardation layer 11 side.
  • Circularly polarized light is emitted from the third retardation layer 13 side, or circularly polarized light is incident from the third retardation layer 13 side and linearly polarized light is emitted from the first retardation layer 11 side.
  • the first retardation layer 11 includes a first liquid crystal layer 110
  • the second retardation layer 12 includes a second liquid crystal layer 120
  • the third retardation layer 13 includes a third liquid crystal layer. 130 included.
  • the retardation R1 of the first retardation layer 11, the retardation R2 of the second retardation layer 12, and the retardation R3 of the third retardation layer 13 are each 20 nm or more, and R1, R2 and R3 were compared. At this time, the retardation Rtha in the thickness direction of the retardation layer having the largest retardation is positive.
  • the retardation R1 of the first retardation layer 11, the retardation R2 of the second retardation layer 12, and the retardation R3 of the third retardation layer 13 are preferably 30 nm or more, more preferably 40 nm or more.
  • RthB is negative or Rthb is positive and Rthc is negative.
  • FIG. 12 shows the output-side slow axis 116e of the first retardation layer 11 on the side of the second retardation layer 12, and the incident side of the second retardation layer 12 on the side of the first retardation layer 11.
  • FIG. 11 is a diagram illustrating a slow axis azimuth angle ⁇ c formed with the side slow axis 116s;
  • FIG. 12 shows an example in which the output-side slow axis 116e and the incident-side slow axis 116s are parallel to the XY plane, at least one of the output-side slow axis 116e and the incident-side slow axis 116s It may be tilted with respect to the XY plane.
  • the slow axis azimuth angle ⁇ c is the angle formed by the output-side slow axis 116e and the incident-side slow axis 116s in the three-dimensional space.
  • the thickness direction in which the liquid crystal molecules 115 are twisted and aligned corresponds to the Z direction in FIG.
  • the following method can be applied to control the slow axis azimuth angle ⁇ c.
  • the first retardation layer 11 and the second retardation layer 12 are appropriately or collectively bonded together.
  • the third retardation layer 13 is provided, the first retardation layer 11, the second retardation layer 12, and the third retardation layer 13 are appropriately adjusted after their respective axis angles are adjusted. Alternatively, they are stuck together.
  • the axis angle means the angle formed by the slow axis of each layer with respect to the reference.
  • the axis angle of each layer can be determined, for example, based on the external shape of the measurement sample (wave plate).
  • the bonding angle can also be controlled based on the outer shape of the measurement sample. Note that the reference of the axis angle of each layer does not necessarily have to be the outer shape, and for example, the alignment mark of the measurement sample can be used as the reference.
  • the axial angle may be measured using, for example, an Axoscan device from Axometrics, or a device such as RE-100 from Otsuka Electronics, and analysis software attached thereto.
  • the torsion angle can also be similarly measured using the above device and analysis software. Using the axial angle and the twist angle obtained from these, the slow axis azimuth angle ⁇ c between the output-side slow axis 116e and the incident-side slow axis 116s can be measured.
  • FIG. 13 is a diagram illustrating the in-plane retardation Re1 of the first retardation layer 11 at a wavelength of 550 nm.
  • FIG. 13 shows an electric field component P1X and an electric field component P1Y incident on the first retardation layer 11, and an electric field component P1X' and an electric field component P1Y' emitted from the first retardation layer 11.
  • FIG. The distance by which the electric field component P1Y' in the first retardation layer 11 lags behind the electric field component P1X' corresponds to the in-plane retardation Re1.
  • the distance by which the electric field component P1Y' in the second retardation layer 12 lags behind the electric field component P1X' corresponds to the in-plane retardation Re2.
  • a prism coupler is a device that measures the refractive index of a thin film formed on a substrate.
  • An ellipsometer is a device that measures the polarization state of polarized light incident on a material surface and reflected by the material surface, and measures the refractive index of the material or the thickness and refractive index of a thin film formed on the material surface.
  • the in-plane retardation Re and the retardation Rth in the thickness direction can be measured using, for example, an Axoscan device manufactured by Axometrics, RE-100 manufactured by Otsuka Electronics Co., Ltd., KOBRA manufactured by Oji Keisoku Co., Ltd., and analysis software attached to each device.
  • the retardation R can also be measured by calculating "(ne ⁇ no) ⁇ t" using the extraordinary refractive index ne, the ordinary refractive index no, and the film thickness t measured by a prism coupler or an ellipsometer.
  • the film thickness t can be measured by, for example, using Mitutoyo's ABS Digimatic Indicator ID-C112CX, cutting a sample, observing the cross section with an SEM, and measuring the length.
  • the extraordinary refractive index ne and the ordinary refractive index no can be measured by measuring a test sample in which the target liquid crystal molecules are horizontally aligned on the substrate with the prism coupler, ellipsometer, or the like. .
  • the ellipticity of the circularly polarized light obtained by converting the linearly polarized visible light incident on the wave plate by the wave plate was calculated and evaluated by simulation.
  • the incident angle and incident azimuth angle were varied, and the ellipticity was calculated for each of a plurality of incident angles and incident azimuth angles.
  • FIG. 14 is a diagram for explaining the incident angle and incident azimuth angle of light incident on the wave plate.
  • the XY plane is a plane parallel to the interface 10 of the wave plate 1
  • the Z-axis is the normal to the interface 10.
  • the incident angle ⁇ is the angle formed by the incident direction of the linearly polarized light P1 incident on the boundary surface 10 and the Z axis.
  • the incident azimuth angle ⁇ is the angle between the azimuth of the linearly polarized light P1 and the X-axis, which is the reference azimuth, within the boundary surface 10 .
  • the slow axis azimuth angle ⁇ c is the angle formed by the slow axis 116 in each of the first retardation layer 11, the second retardation layer 12, and the third retardation layer 13 with respect to the X axis.
  • FIG. 15 is a diagram for explaining the ellipticity of polarized light.
  • An ellipse E represents the trajectory of the electric field of the light traveling along the Z axis, viewed from the traveling direction. If the length of the major axis of the ellipse E is a and the length of the minor axis is b, the ellipticity ⁇ is b/a.
  • the ellipticity ⁇ is 1, the light is circularly polarized light, and when the ellipticity ⁇ is 0 or infinite, the light is linearly polarized light.
  • the closer the ellipticity ⁇ is to 1 the higher the ellipticity and the higher the performance of the wave plate 1 is.
  • the ellipticity area In order to evaluate using the ellipticity ⁇ obtained at multiple incident angles and incident azimuth angles and the ellipticity ⁇ obtained for each wavelength ⁇ within the wavelength range of visible light, the ellipticity area is used as an evaluation index. Using.
  • FIG. 16 and 17A are diagrams for explaining the ellipticity area.
  • FIG. 16 is a diagram illustrating changes in ellipticity ⁇ with wavelength ⁇ .
  • FIG. 17A is a diagram extracting and showing a rectangular region 151 showing the ellipticity ⁇ within the range of ⁇ in FIG.
  • the ellipticity ⁇ ( ⁇ 0) at the shortest wavelength ⁇ 0 and the ellipticity ⁇ ( ⁇ 1) at the longest wavelength ⁇ 1, which is the average value of the ellipticity ⁇ (avg ) was calculated, and the area of the rectangular region 151 was calculated from the product of the wavelength width ⁇ and ⁇ (avg.).
  • the total sum of the area addition values of the rectangular regions 151 obtained at each of a plurality of incident angles and incident azimuth angles was defined as the ellipticity area.
  • Table 1 shows the configurations and evaluation results of Examples and Comparative Examples. Examples 1 to 6 are examples, and examples 7 and 8 are comparative examples.
  • Table 1 shows each configuration of the first retardation layer 11, the second retardation layer 12, and the third retardation layer 13 for each example and comparative example.
  • Wave plates 1 according to Examples 3 and 7 included a first retardation layer 11 and a second retardation layer 12 .
  • Wave plates 1 according to examples other than Examples 3 and 7 include a first retardation layer 11 , a second retardation layer 12 , and a third retardation layer 13 .
  • the wave plates 1 according to Examples 1 to 8 enter the linearly polarized light P1 from the side of the first retardation layer 11 and emit the circularly polarized light P2 from the side opposite to the first retardation layer 11, or Circularly polarized light P2 is incident from the side opposite to the first retardation layer 11, and linearly polarized light P1 is emitted from the first retardation layer 11 side.
  • the circularly polarized light P2 is incident, in Examples 1, 2, 4, 5, 6 and 8, the circularly polarized light P2 is incident from the third retardation layer 13, and in Examples 3 and 7, the Circularly polarized light P2 is incident from the second retardation layer 12 .
  • “Incident polarized light” indicates the polarization axis direction of the linearly polarized light P1 incident on or emitted from the first retardation layer 11 .
  • "X” and “Y” indicate that the polarization axis is along the X axis and the Y axis, respectively.
  • the polarization axis azimuth ⁇ 0 of the linearly polarized light P1 is not limited to along the X-axis or the Y-axis.
  • the polarization axis azimuth angle ⁇ 0 of the linearly polarized light P1 is appropriately set according to the intended use of the wave plate 1. It is possible.
  • the polarization axis azimuth ⁇ 0 of the linearly polarized light P1 can be set so as to obtain polarized light with a higher ellipticity depending on the intended use of the wave plate 1 .
  • Liquid crystal layer in each retardation layer indicates the type of liquid crystal layer.
  • Positive dispersion twist indicates a twisted liquid crystal layer having positive dispersion
  • reverse dispersion twist indicates a twisted liquid crystal layer having reverse dispersion.
  • Reverse dispersion a-plate is a horizontally aligned liquid crystal layer having reverse dispersion
  • vertical c-plate is a vertically aligned liquid crystal layer
  • positive dispersion a-plate is positive dispersion. 1 shows a liquid crystal layer with horizontal alignment.
  • ⁇ c_s1 (°) is the slow axis azimuth on the light incident side in the first retardation layer 11
  • ⁇ c_s2 (°) is the slow axis azimuth on the light incident side in the second retardation layer 12.
  • the angle “ ⁇ c_s3 (°)” indicates the slow axis azimuth angle of the third retardation layer 13 on the light incident side.
  • the azimuth angle of the slow axis on the light incident side is collectively referred to as ⁇ c_s without distinguishing between the retardation layers.
  • ⁇ c_e1 (°) is the slow axis azimuth angle on the light output side of the first retardation layer 11
  • ⁇ c_e2 (°) is the slow axis azimuth on the light output side of the second retardation layer 12.
  • the angle “ ⁇ c_e3(°)” indicates the slow axis azimuth angle of the third retardation layer 13 on the light exit side.
  • the azimuth angle of the slow axis on the light exit side is collectively referred to as ⁇ c_e without distinguishing between the retardation layers.
  • the slow axis azimuth angle ⁇ c_s and the slow axis azimuth angle ⁇ c_e are angles relative to the reference.
  • the X-axis is used as a reference, but it is not limited to this, and can be set as appropriate according to the intended use of the wave plate 1 or the like.
  • the liquid crystal molecules are oriented in a direction perpendicular to the interface 10, and the slow axis is perpendicular to the X axis.
  • the slow axis azimuth angle ⁇ c_e is expressed as “90°”.
  • the slow axis azimuth angle ⁇ c_s and the slow axis azimuth angle ⁇ c_e represent angles with respect to the X-axis in a plane substantially parallel to the interface 10 . Counterclockwise is positive, clockwise is negative.
  • the "twist angle” represents the maximum angular difference within the boundary plane 10 between the slow axes of a plurality of liquid crystal molecules twisted and aligned in the thickness direction in the twisted liquid crystal layer. In the horizontally aligned and vertically aligned liquid crystal layers, the “twist angle” is “0" because the plurality of liquid crystal molecules are aligned in a substantially constant direction.
  • the twist angle can be measured using, for example, an Axoscan device from Axometrics, RE-100 from Otsuka Electronics, or the like, and analysis software attached to each device.
  • “Film thickness ( ⁇ m)” is the film thickness of the liquid crystal layer
  • “Re1 (nm)” is the in-plane retardation in the first retardation layer 11
  • “Re2 (nm)” is the in-plane retardation in the second retardation layer 12.
  • Retardation “Re3 (nm)” indicates in-plane retardation in the third retardation layer 13 .
  • the in-plane retardation corresponds to a wavelength ⁇ of 550 nm.
  • the film thickness of the liquid crystal layer can be measured by, for example, Mitutoyo's ABS Digimatic Indicator ID-C112CX, cutting a sample, observing the cross section with an SEM, and measuring the length.
  • the in-plane retardations Re1, Re2, and Re3 can be measured using, for example, an Axoscan device from Axometrics, or RE-100 from Otsuka Electronics, and analysis software attached to each device. Alternatively, it can be measured by calculating "(ne ⁇ no) ⁇ t" from the extraordinary refractive index ne, the ordinary refractive index no, and the film thickness t obtained by a prism coupler, ellipsometer, or the like.
  • R1 (nm) is the retardation in the first retardation layer 11
  • R2 (nm) is the retardation in the second retardation layer 12
  • R3 (nm) is the retardation in the third retardation layer 13.
  • the retardations R1, R2, and R3 can be measured using, for example, an Axoscan device from Axometrics, RE-100 from Otsuka Electronics, or the like, and analysis software attached to each device. Also, R1, R2 and R3 can be measured by calculating "(ne ⁇ no) ⁇ t" from the extraordinary refractive index ne, the ordinary refractive index no and the film thickness t obtained by a prism coupler or an ellipsometer. When measuring the retardation of vertical alignment, the extraordinary refractive index ne and the ordinary refractive index no can be measured by measuring a test sample in which target liquid crystal molecules are horizontally aligned on a substrate with a prism coupler, an ellipsometer, or the like.
  • Rth (nm) is the retardation in the thickness direction of the retardation layer.
  • the retardation corresponds to a wavelength ⁇ of 550 nm.
  • RthA (nm) is the retardation of the A layer in the thickness direction.
  • RthB (nm) is the retardation in the thickness direction of the B layer.
  • a layer with a large in-plane retardation corresponds to the A layer
  • a layer with a small in-plane retardation corresponds to the B layer.
  • Rtha is the retardation in the thickness direction of the a layer.
  • Rthb is the retardation in the thickness direction of the b layer.
  • Rthc is the retardation in the thickness direction of the c layer.
  • the layers correspond to the a layer, the b layer and the c layer in order from the layer having the largest in-plane retardation Re1, Re2 and Re3 to the smallest.
  • Retardations Rtha, Rthb, Rthc, RthA, and RthB in the thickness direction can be obtained, for example, by Axoscan equipment from Axometrics, RE-100 from Otsuka Electronics, KOBRA from Oji Keisoku Co., Ltd., and analysis software attached to each equipment. and can be measured using
  • the material of the first retardation layer 11 As the material of the first retardation layer 11, the material A was used in Examples 1, 4, 5, 6, 7, and 8, and the material B was used in Examples 2 and 3, respectively.
  • the material of the second retardation layer 12 As the material of the second retardation layer 12, the material C was used in Examples 1, 3, 5, 6 and 8, the material A was used in Examples 4 and 7, and the material B was used in Example 2.
  • the material of the third retardation layer 13 As the material of the third retardation layer 13, the material A was used in Examples 1, 5, 6, and 8, the material B was used in Example 2, and the material C was used in Example 4, respectively.
  • ⁇ c (°) is defined by the slow axis azimuth angle ⁇ c_e1 on the light output side in the first retardation layer 11 and the slow axis azimuth angle ⁇ c_s2 on the light incident side in the second retardation layer 12. Show the corners. “ ⁇ c(°)” corresponds to the difference value between the slow axis azimuth angle ⁇ c_e1 and the slow axis azimuth angle ⁇ c_s2.
  • the slow axis azimuth angle ⁇ c_s2 of the second retardation layer 12 including the vertically aligned liquid crystal layer is the slow axis of the first retardation layer 11 including the horizontally aligned or twisted liquid crystal layer. Since it is perpendicular to the azimuth angle ⁇ c_e1, that is, it is three-dimensionally perpendicular, it is written as “90°”.
  • the angle formed by the slow axis azimuth angle ⁇ c_e1 and the slow axis azimuth angle ⁇ c_s2 may be an angle formed in the three-dimensional coordinate system of the wave plate 1 .
  • the angle formed by the wave plate 1 in the three-dimensional coordinate system is a three-dimensional crossing angle.
  • the three-dimensional coordinate system of the wave plate 1 means a coordinate system defined by a total of three directions, namely, the thickness direction of the wave plate 1 and two orthogonal directions in a plane perpendicular to the thickness direction. .
  • FIG. 17B and C17 are schematic diagrams for explaining the three-dimensional intersection angle of the slow axis azimuth angles of Example 1.
  • FIG. 17B schematically shows an example of orientation of liquid crystal molecules contained in each of the first retardation layer 11, the second retardation layer 12, and the third retardation layer 13 in the wave plate 1.
  • FIG. 17B schematically shows an example of orientation of liquid crystal molecules contained in each of the first retardation layer 11, the second retardation layer 12, and the third retardation layer 13 in the wave plate 1.
  • FIG. 17C shows the three-dimensional intersection angle of the alignment directions of the two liquid crystal molecules included in FIG. 17B.
  • the alignment direction 71 represents the alignment direction of the liquid crystal molecules contained in the first retardation layer 11 .
  • the alignment direction 72 represents the alignment direction of the liquid crystal molecules contained in the second retardation layer 12 .
  • a crossing angle 73 represents a three-dimensional crossing angle between the alignment directions 71 and 72 .
  • the alignment direction 71 and the alignment direction 72 are orthogonal, and the value of the crossing angle 73 is 90 degrees.
  • a crossing angle 73 corresponds to a three-dimensional crossing angle between the slow axis azimuth angle ⁇ c_e1 and the slow axis azimuth angle ⁇ c_s2.
  • “Ellipticity evaluation result” indicates the evaluation result of the ellipticity area. "O” indicates that the area is 250 or more, and “X” indicates that the area is less than 250. If the ellipticity area is 250 or more, the ellipticity is high in a wide viewing angle and in a wide band.
  • the first liquid crystal layer 110 included in the first retardation layer 11 and the second liquid crystal layer included in the second retardation layer 12 In at least one of 120, the liquid crystal molecules 115 are twisted and oriented in the thickness direction, and the azimuth angle ⁇ c of the slow axis is set to 10° or more.
  • the slow axis azimuth angle ⁇ c is set to 10° or more
  • the retardations R1 and R2 are set to 20 nm or more in the case of the two-layer structure
  • the retardations R1, R2 and R3 are set to the three-layer structure. 20 nm or more.
  • the retardation RthA in the thickness direction of the A layer in the two-layer structure and the retardation Rtha in the thickness direction of the a layer in the three-layer structure were positive (>0).
  • Example 7 the slow axis azimuth angle ⁇ c was made smaller than 10° although the liquid crystal layer had liquid crystal molecules that were twisted and aligned.
  • Example 8 does not include a liquid crystal layer with twisted liquid crystal molecules and R2 ⁇ 20 nm.
  • the ellipticity evaluation results were " ⁇ " for Examples 1 to 6, and "X” for Examples 7 and 8.
  • Table 2 shows the calculation results of the ellipticity area used in the ellipticity evaluation. As shown in Table 2, in each of Examples 1 to 6, a larger ellipticity area than in Examples 7 and 8 was obtained.
  • FIG. 18 is an example of a contour diagram of the ellipticity ⁇ in Example 1
  • FIG. 19 is an example in Example 7. 18 and 19 show the ellipticity distribution when the wave plate 1 is viewed from above.
  • the numerical values 0 to 50 displayed along the radial direction represent the incident angle ⁇ .
  • Numerical values [0] to [330] displayed counterclockwise along the circumferential direction represent incident azimuth angles ⁇ .
  • the unit of the incident angle ⁇ and the incident azimuth angle ⁇ is [°].
  • the density of the color bar represents the magnitude of the ellipticity ⁇ .
  • the ellipticity ⁇ generally increases at the incident angle ⁇ from 0° to 50° and the incident azimuth angle ⁇ from 0° to 360°, and the difference in the ellipticity ⁇ is got smaller.
  • Example 7 a high ellipticity was obtained in the region where the incident angle ⁇ was small, but the ellipticity ⁇ decreased as the incident angle ⁇ increased. The difference in ellipticity ⁇ depending on the incident azimuth angle ⁇ was also increased compared to Example 1.
  • FIG. 20 is an example 1
  • FIG. 21 is an example 7, and each is a figure which illustrates the change of the ellipticity (epsilon) according to the wavelength (lambda).
  • the horizontal axis indicates the wavelength ⁇
  • the vertical axis indicates the ellipticity ⁇ .
  • Both incident azimuth angles ⁇ are 0°.
  • the wavelength ⁇ ranges from 400 nm to 700 nm
  • the incident angle ⁇ ranges from 0° to 70°.
  • the graph is displayed with different line types according to the incident angle ⁇ .
  • Example 1 the ellipticity ⁇ is at a minimum of approximately 0.7 at a wavelength ⁇ of 700 nm, and in Example 7, at a wavelength ⁇ of 400 nm, the ellipticity ⁇ is at a minimum of approximately 0.52. rice field. That is, in Example 1, compared with Example 7, the ellipticity ⁇ was increased as a whole. The maximum value of the ellipticity ⁇ for each incident angle ⁇ varied from about 1.0 (when the incident angle ⁇ was 0°) to about 0.88 (when the incident angle ⁇ was 70°) in Example 1.
  • Example 7 it varied from about 1.0 (when the incident angle ⁇ was 0°) to about 0.61 (when the incident angle ⁇ was 70°). That is, in Example 1, the difference in ellipticity ⁇ according to the incident angle ⁇ was smaller than in Example 7.
  • Example 1 has two or less upwardly convex peaks.
  • Examples 2 to 6 similarly have two or less upwardly convex peaks in the wavelength range of 400 nm to 700 nm. If the number of upwardly convex peaks in the above wavelength range is two or less, the ellipticity distribution in the corresponding wavelength range becomes uniform, circularly polarized light with the same ellipticity can be obtained in a wide band, and polarization control is achieved. become easier.
  • the present embodiment can provide the wave plate 1 capable of converting the polarization state of light incident on the wave plate over a wide range of incident angles and incident azimuth angles with high ellipticity.
  • the wavelength plate 1 converts the polarization state with a high ellipticity, so that when the linearly polarized light P1 is incident, it can emit circularly polarized light P2 with a higher ellipticity, and when the circularly polarized light P2 is incident, the polarized light Linearly polarized light P1 with a higher extinction ratio can be emitted.
  • the polarization extinction ratio is an index for expressing the extent to which orthogonally polarized light is separated, and is represented, for example, by the light intensity ratio of P polarized light and S polarized light, which are orthogonal polarized lights.
  • the wave plate 1 is a laminated wave plate, it is easy to manufacture, and it is possible to make the wave plate thinner.
  • Embodiments include optics.
  • the optical system according to the embodiment includes at least one or more of a first polarizing plate L1, a second polarizing plate, or a second wave plate Q, and a wave plate 1.
  • the first polarizing plate L1 is arranged on the side of the wavelength plate 1 on which linearly polarized light is incident or emitted.
  • the second wave plate Q has either the same configuration as the wave plate 1 or a configuration different from the wave plate 1 .
  • the second polarizing plate is arranged on the side of the second wavelength plate Q on which the linearly polarized light is incident or emitted.
  • FIG. 22 is a diagram illustrating the configuration of the optical system 100 according to the embodiment.
  • the optical system 100 includes a first polarizing plate L1.
  • the first polarizing plate L1 is arranged on the side of the wavelength plate 1 on which the linearly polarized light P3 is incident.
  • the first polarizing plate L1 receives the randomly polarized light P10 and outputs the linearly polarized light P3.
  • Wave plate 1 converts linearly polarized light P3 into circularly polarized light P2.
  • the linearly polarized light P3 with the desired polarization axis azimuth angle can be extracted from the random polarized light P10, and the proportion of the circularly polarized light P2 in the light emitted from the wave plate 1 can be increased. can do.
  • the first polarizing plate L1 is arranged on the side of the wavelength plate 1 from which the linearly polarized light is emitted.
  • the first polarizing plate L1 may be arranged in contact with the first retardation layer 11 as shown in FIG. This arrangement can provide a thin optical system 100 . Further, another layer such as a half mirror, a base film, an adhesive layer, etc. may be provided between the wavelength plate 1 and the first polarizing plate L1.
  • FIG. 24 is a diagram illustrating the configuration of the optical system 100a according to the embodiment.
  • the optical system 100a includes a second polarizing plate L2 and a second wave plate Q.
  • the second polarizing plate L2 and the second wave plate Q are arranged on the side opposite to the side where the wave plate 1 emits the linearly polarized light P4.
  • the second wave plate Q receives the linearly polarized light P3 emitted from the second polarizing plate L2 that receives the randomly polarized light P10, and emits the circularly polarized light P5.
  • Wave plate 1 converts circularly polarized light P5 into linearly polarized light P4.
  • the second polarizing plate L2 can be omitted depending on the degree of polarization of the light source itself and the desired polarization extinction ratio.
  • the wave plate 1 corresponds to the first wave plate.
  • the second wave plate Q may have the same configuration as the wave plate 1 or may have a different configuration from the wave plate 1 .
  • the optical system 100a can cause the wave plate 1 to receive the circularly polarized light P5 and emit the linearly polarized light P4.
  • the optical system 100a can also arrange the first polarizing plate L1 on the opposite side of the wave plate 1 to the second wave plate Q. With this configuration, the optical system 100a allows the linearly polarized light P4 emitted from the wave plate 1 to pass through the first polarizing plate L1, thereby allowing the optical system 100a to emit linearly polarized light having a higher polarization extinction ratio than the linearly polarized light P4. .
  • the second wave plate Q may be arranged in contact with the second retardation layer 12 as shown in FIG. This arrangement can provide a thin optical system 100a. Further, another layer such as a half mirror, a substrate film, an adhesive layer, etc. may be provided between the wave plate 1 and the second wave plate Q.
  • an optical system having a wave plate capable of converting the polarization state of light incident on the wave plate at a wide incident angle and incident azimuth angle with high ellipticity.
  • the optical system including the two-layer wave plate 1 including the first retardation layer 11 and the second retardation layer 12 is illustrated, but the optical system according to the embodiment is Further, the wave plate 1 having a three-layer structure having a third retardation layer 13 may be provided. In this case, the third retardation layer 13 receives or emits circularly polarized light.
  • the optical systems 100 and 100a are the same as the optical systems 100 and 100a described with reference to FIGS. 22 to 25, except that the wave plate 1 has a three-layer structure, so redundant description will be omitted here.
  • the flexible wave plate 1 can be preferably attached to a three-dimensional structure, particularly a three-dimensional structure having a curved surface, and has a function of converting linearly polarized light into circularly polarized light, or a function of converting circularly polarized light into linearly polarized light.
  • Three-dimensional structures include, for example, lenses, prisms, mirrors, and the like.
  • a lens includes a concave lens including a concave surface, a convex lens including a convex surface, and the like.
  • the three-dimensional structure may be a display device such as a liquid crystal display or an organic EL display.
  • the three-dimensional structure having a curved surface may be a curved display device (curved display) such as a liquid crystal display or an organic EL display.
  • the wave plate and optical system according to the embodiments can be applied to various fields using optical techniques such as display devices such as liquid crystal displays or organic EL displays, optical measurement devices such as polarization measurement devices, or optical heads.
  • optical techniques such as display devices such as liquid crystal displays or organic EL displays, optical measurement devices such as polarization measurement devices, or optical heads.
  • display devices such as liquid crystal displays or organic EL displays
  • optical measurement devices such as polarization measurement devices, or optical heads.

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Abstract

The present invention provides: a wavelength plate that makes it possible to convert, by a high degree of ellipticity, the polarization state of light incident on the wavelength plate at a wide incidence angle and a wide incidence azimuth; an optical system that comprises a wavelength plate; and a display device that comprises an optical system. This wavelength plate comprises a first retardation layer and a second retardation layer, and receives linearly polarized light from the first retardation layer side and emits circularly polarized light from the second retardation layer side, or receives circularly polarized light from the second retardation layer side and emits linearly polarized light from the first retardation layer side. The first retardation layer includes a first liquid crystal layer, the second retardation layer includes a second liquid crystal layer, the liquid crystal molecules in at least one among the first liquid crystal layer and the second liquid crystal layer are aligned so as to be twisted in the thickness direction, and the angle formed by the slow axis on the second retardation layer side of the first retardation layer and the slow axis on the first retardation layer side of the second retardation layer is 10° or more in a three-dimensional coordinate system of the wavelength plate.

Description

波長板、光学系、および表示装置Waveplates, optics, and displays
　本開示は波長板、光学系、および表示装置に関する。 The present disclosure relates to waveplates, optical systems, and display devices.
　透過する光の偏光状態を変換する光学素子である波長板が知られている。波長板は、液晶ディスプレイ又は有機ＥＬ（Electro Luminescence）ディスプレイ等の表示装置における視野角補償又は反射防止、あるいは光学測定等の多様な用途で用いられている。目的に応じて、入射光を円偏光又は直線偏光等に変換することにより、表示品質の改善、物質の性質の観測、バックグラウンドノイズの除去等が行われる。 A wave plate, which is an optical element that converts the polarization state of transmitted light, is known. Wave plates are used in various applications such as viewing angle compensation or antireflection in display devices such as liquid crystal displays or organic EL (Electro Luminescence) displays, or optical measurements. By converting incident light into circularly polarized light or linearly polarized light according to the purpose, improvement of display quality, observation of material properties, removal of background noise, etc. are performed.
　波長板として、複数の光学異方性層を積層した位相差フィルムが知られている（たとえば、特許文献１参照）。また、第１の液晶層と第２の液晶層とを含み、第１の液晶層における第２の液晶層側の遅相軸の角度が、第２の液晶層における第１の液晶層側の遅相軸の角度と等しい構成が開示されている（例えば、特許文献２参照）。 As a wave plate, a retardation film in which a plurality of optically anisotropic layers are laminated is known (see Patent Document 1, for example). Further, it includes a first liquid crystal layer and a second liquid crystal layer, and the angle of the slow axis of the first liquid crystal layer on the second liquid crystal layer side is the same as that of the second liquid crystal layer on the first liquid crystal layer side. A configuration equal to the angle of the slow axis is disclosed (see, for example, Patent Document 2).
特許第６５７１１６７号公報Japanese Patent No. 6571167 米国特許第９２９８０４１号明細書U.S. Pat. No. 9,298,041
　波長板は、広い入射角および入射方位角において波長板に入射する可視光の偏光状態を、高い楕円率により変換することが求められている。 A wave plate is required to convert the polarization state of visible light incident on the wave plate over a wide range of incident angles and incident azimuth angles with high ellipticity.
　ここで、可視光とは、人間の目により見える波長の光をいう。可視光は、例えば波長が３８０ｎｍから７８０ｎｍの範囲内にある光である。入射角とは、光が波長板に入射するときの入射方向と、波長板における境界面の法線と、がなす角をいう。入射方位角とは、波長板の境界面内において、波長板に入射する光の方位と、基準となる方位と、がなす角をいう。境界面とは、波長板と大気との境界を含む面をいう。 Here, visible light refers to light with a wavelength visible to the human eye. Visible light is, for example, light having a wavelength in the range of 380 nm to 780 nm. The incident angle is the angle formed by the direction of incidence of light on the wavelength plate and the normal to the boundary surface of the wavelength plate. The incident azimuth angle is the angle formed by the azimuth of light incident on the wave plate and the reference azimuth within the boundary plane of the wave plate. A boundary surface refers to a surface that includes the boundary between the wave plate and the atmosphere.
　楕円率とは、円偏光と直線偏光の間の偏光状態である楕円偏光における楕円の長軸の長さと短軸の長さの比をいう。長軸の長さと短軸の長さが等しい場合に楕円率は１になる。楕円率は、偏光が円偏光に近いか、あるいは直線偏光に近いかを表す指標となる。楕円率が１に近づくほど、偏光は円偏光に近いことを意味し、楕円率が０に近づくほど、偏光は直線偏光に近いことを意味する。 Ellipticity is the ratio of the length of the major axis to the length of the minor axis of elliptically polarized light, which is the state of polarization between circularly polarized light and linearly polarized light. The ellipticity is 1 when the length of the major axis is equal to the length of the minor axis. The ellipticity is an index representing whether the polarized light is close to circularly polarized light or linearly polarized light. The closer the ellipticity is to 1, the closer the polarization is to circular polarization, and the closer the ellipticity is to 0, the closer the polarization is to linear polarization.
　高い楕円率により変換するとは、入射する直線偏光を１に近い楕円率の楕円偏光に変換すること、あるいは入射する円偏光を０に近い楕円率の楕円偏光に変換することをいう。 Converting with a high ellipticity means converting incident linearly polarized light into elliptically polarized light with an ellipticity close to 1, or converting incident circularly polarized light into elliptically polarized light with an ellipticity close to 0.
　本開示の一態様は、広い入射角および入射方位角において波長板に入射する光の偏光状態を、高い楕円率により変換可能な波長板、波長板を備える光学系、または、光学系を備える表示装置を提供することを目的とする。 One aspect of the present disclosure is a wave plate capable of converting the polarization state of light incident on the wave plate at a wide incident angle and incident azimuth angle with high ellipticity, an optical system including the wave plate, or a display including the optical system The purpose is to provide an apparatus.
　本開示の一態様に係る波長板は、第１の位相差層および第２の位相差層を備え、前記第１の位相差層側から直線偏光を入射して前記第２の位相差層側から円偏光を出射し、又は、前記第２の位相差層側から円偏光を入射して前記第１の位相差層側から直線偏光を出射する波長板であって、前記第１の位相差層は、第１の液晶層を含み、前記第２の位相差層は、第２の液晶層を含み、前記第１の液晶層および前記第２の液晶層の少なくとも一以上は、厚さ方向に液晶分子がねじれて配向しており、前記波長板の三次元座標系において、前記第１の位相差層における前記第２の位相差層側の遅相軸と、前記第２の位相差層における前記第１の位相差層側の遅相軸と、がなす角が１０°以上である。 A wave plate according to one aspect of the present disclosure includes a first retardation layer and a second retardation layer, linearly polarized light is incident from the first retardation layer side to the second retardation layer side A wave plate for emitting circularly polarized light from, or for emitting circularly polarized light from the second retardation layer side and emitting linearly polarized light from the first retardation layer side, wherein the first retardation layer The layers include a first liquid crystal layer, the second retardation layer includes a second liquid crystal layer, and at least one of the first liquid crystal layer and the second liquid crystal layer extends in the thickness direction. liquid crystal molecules are twisted and aligned, and in the three-dimensional coordinate system of the wave plate, the slow axis of the first retardation layer on the side of the second retardation layer and the second retardation layer and the slow axis on the side of the first retardation layer in is 10° or more.
　本開示の一態様に係る波長板は、第１の位相差層および第２の位相差層を備え、前記第１の位相差層側から直線偏光を入射して前記第２の位相差層側から円偏光を出射し、又は、前記第２の位相差層側から円偏光を入射して前記第１の位相差層側から直線偏光を出射する波長板であって、前記第１の位相差層は、第１の液晶層を含み、前記第２の位相差層は、第２の液晶層を含み、前記第１の位相差層の波長５５０ｎｍにおけるリタデーションＲ１および前記第２の位相差層の波長５５０ｎｍにおけるリタデーションＲ２は、それぞれ２０ｎｍ以上であり、Ｒ１およびＲ２を比較したとき、大きい方の厚さ方向のリタデーションＲｔｈＡは正である。 A wave plate according to one aspect of the present disclosure includes a first retardation layer and a second retardation layer, linearly polarized light is incident from the first retardation layer side to the second retardation layer side A wave plate for emitting circularly polarized light from, or for emitting circularly polarized light from the second retardation layer side and emitting linearly polarized light from the first retardation layer side, wherein the first retardation layer The layer includes a first liquid crystal layer, the second retardation layer includes a second liquid crystal layer, and the retardation R1 of the first retardation layer at a wavelength of 550 nm and the Each retardation R2 at a wavelength of 550 nm is 20 nm or more, and when R1 and R2 are compared, the larger thickness retardation RthA is positive.
　本開示の一態様に係る波長板は、第１の位相差層、第２の位相差層、および第３の位相差層をこの順に備え、前記第１の位相差層側から直線偏光を入射して前記第３の位相差層側から円偏光を出射し、又は、前記第３の位相差層側から円偏光を入射して前記第１の位相差層側から直線偏光を出射する波長板であって、前記第１の位相差層は、第１の液晶層を含み、前記第２の位相差層は、第２の液晶層を含み、前記第３の位相差層は、第３の液晶層を含み、前記第１の位相差層の波長５５０ｎｍにおけるリタデーションＲ１、前記第２の位相差層の波長５５０ｎｍにおけるリタデーションＲ２、および前記第３の位相差層の波長５５０ｎｍにおけるリタデーションＲ３は、それぞれ２０ｎｍ以上であり、Ｒ１、Ｒ２およびＲ３を比較したとき、一番大きい厚さ方向のリタデーションＲｔｈａは正である。 A wave plate according to one aspect of the present disclosure includes a first retardation layer, a second retardation layer, and a third retardation layer in this order, and linearly polarized light is incident from the first retardation layer side. to emit circularly polarized light from the third retardation layer side, or to emit circularly polarized light from the third retardation layer side and emit linearly polarized light from the first retardation layer side wherein the first retardation layer includes a first liquid crystal layer, the second retardation layer includes a second liquid crystal layer, and the third retardation layer includes a third Including a liquid crystal layer, the retardation R1 at a wavelength of 550 nm of the first retardation layer, the retardation R2 at a wavelength of 550 nm of the second retardation layer, and the retardation R3 at a wavelength of 550 nm of the third retardation layer are each It is 20 nm or more, and when R1, R2 and R3 are compared, the largest thickness retardation Rtha is positive.
　本開示の一態様によれば、広い入射角および方位角で波長板に入射する光の偏光状態を、高い楕円率により変換可能な波長板、波長板を備えた光学系、または、光学系を備えた表示装置を提供できる。 According to one aspect of the present disclosure, a wavelength plate capable of converting the polarization state of light incident on the wavelength plate at a wide angle of incidence and azimuth angle with high ellipticity, an optical system including the wavelength plate, or an optical system It is possible to provide a display device equipped with
実施形態に係る波長板の構成を例示する平面図である。3 is a plan view illustrating the configuration of a wave plate according to the embodiment; FIG. 図１のI－I切断線に沿う第１例の断面図である。FIG. 2 is a cross-sectional view of the first example taken along the II section line of FIG. 1; 図１のI－I切断線に沿う第２例の断面図である。FIG. 2 is a cross-sectional view of the second example taken along the II section line of FIG. 1; 実施形態に係る波長板による偏光状態の変換を例示する図である。It is a figure which illustrates the conversion of the polarization state by the wavelength plate which concerns on embodiment. 水平配向している液晶層を例示する断面図である。FIG. 4 is a cross-sectional view illustrating a horizontally aligned liquid crystal layer; 水平配向している液晶層を例示する平面図である。FIG. 4 is a plan view illustrating a horizontally aligned liquid crystal layer; 垂直配向している液晶層を例示する断面図である。FIG. 4 is a cross-sectional view illustrating a vertically aligned liquid crystal layer; ねじれ配向している液晶層を例示する断面図である。FIG. 4 is a cross-sectional view illustrating a twisted liquid crystal layer; 光入射側から視た図８の液晶層を例示する平面図である。9 is a plan view illustrating the liquid crystal layer of FIG. 8 viewed from the light incident side; FIG. 光出射側から視た図８の液晶層を例示する平面図である。9 is a plan view illustrating the liquid crystal layer of FIG. 8 viewed from the light exit side; FIG. 図１０Ｂ（Ａ）は透明基材と配向層の一例を示す斜視図であり、図１０Ｂ（Ｂ）は図１０Ｂ（Ａ）に示す配向層によって配向された液晶分子の一例を示す斜視図である。10B(A) is a perspective view showing an example of a transparent substrate and an alignment layer, and FIG. 10B(B) is a perspective view showing an example of liquid crystal molecules aligned by the alignment layer shown in FIG. 10B(A). . 複数の溝を有する波長板の構成の一例を示す図であり、図１０Ｃ（Ａ）は微視的に視た断面図、図１０Ｃ（Ｂ）は巨視的に視た断面図である。FIG. 10C(A) is a microscopic sectional view, and FIG. 10C(B) is a macroscopic sectional view showing an example of a configuration of a wave plate having a plurality of grooves; 液晶層における波長分散性を説明する図である。It is a figure explaining the wavelength dispersion in a liquid crystal layer. 第１の位相差層における第２の位相差層側の遅相軸と、第２の位相差層における第１の位相差層側の遅相軸とのなす角を例示する図である。FIG. 4 is a diagram illustrating an angle formed between a slow axis of a first retardation layer on the side of the second retardation layer and a slow axis of the second retardation layer on the side of the first retardation layer. 実施形態に係る第１の位相差層の面内リタデーションを例示する図である。It is a figure which illustrates the in-plane retardation of the 1st retardation layer which concerns on embodiment. 波長板に入射する光の入射角および入射方位角を説明する図である。It is a figure explaining the incident angle and incident azimuth angle of the light which injects into a wavelength plate. 偏光の楕円率を説明する図である。It is a figure explaining the ellipticity of polarized light. 波長に伴う楕円率の変化を例示する図である。FIG. 4 is a diagram illustrating changes in ellipticity with wavelength; 図１６におけるΔλの範囲を取り出して示した図である。17 is a diagram extracting and showing the range of Δλ in FIG. 16; FIG. 例１の遅相軸方位角の三次元的な交差角を示す第１模式図である。3 is a first schematic diagram showing three-dimensional intersection angles of slow axis azimuth angles of Example 1. FIG. 例１の遅相軸方位角の三次元的な交差角を示す第２模式図である。3 is a second schematic diagram showing a three-dimensional intersection angle of slow axis azimuth angles of Example 1. FIG. 実施例１における楕円率のコンター図である。4 is a contour diagram of ellipticity in Example 1. FIG. 比較例における楕円率のコンター図である。It is a contour figure of the ellipticity in a comparative example. 実施例１における波長に応じた楕円率変化を例示する図である。4 is a diagram illustrating changes in ellipticity according to wavelength in Example 1. FIG. 比較例における波長に応じた楕円率の変化を例示する図である。It is a figure which illustrates the change of the ellipticity according to the wavelength in a comparative example. 実施形態に係る光学系の構成の第１例を示す図である。It is a figure which shows the 1st example of a structure of the optical system which concerns on embodiment. 実施形態に係る光学系の構成の第２例を示す図である。It is a figure which shows the 2nd example of a structure of the optical system which concerns on embodiment. 実施形態に係る光学系の構成の第３例を示す図である。It is a figure which shows the 3rd example of a structure of the optical system which concerns on embodiment. 実施形態に係る光学系の構成の第４例を示す図である。It is a figure which shows the 4th example of a structure of the optical system which concerns on embodiment.
　以下、図面を参照して発明を実施するための形態について詳細に説明する。但し、以下に示す形態は、本実施形態の技術思想を具現化するための波長板を例示するものであって、以下に限定するものではない。なお、各図面が示す部材の大きさ、位置関係等は、説明を明確にするため誇張していることがある。各図面において、同一構成部分には同一符号を付し、重複した説明を適宜省略する。 Hereinafter, the embodiments for carrying out the invention will be described in detail with reference to the drawings. However, the form shown below is an example of a wave plate for embodying the technical idea of this embodiment, and is not limited to the following. Note that the sizes, positional relationships, etc. of members shown in each drawing may be exaggerated for clarity of explanation. In each drawing, the same components are denoted by the same reference numerals, and overlapping descriptions are omitted as appropriate.
　以下に示す図においてＸ軸、Ｙ軸およびＺ軸により方向を示す場合があるが、Ｘ軸に沿うＸ方向は、実施形態に係る波長板の大気との境界面内における所定方向を示す。Ｙ軸に沿うＹ方向は、上記境界面内においてＸ方向と直交する方向を示し、Ｚ軸に沿うＺ方向は上記境界面に直交する方向を示す。 In the diagrams shown below, directions may be indicated by the X-axis, Y-axis, and Z-axis, but the X-direction along the X-axis indicates a predetermined direction within the interface between the wave plate according to the embodiment and the atmosphere. The Y-direction along the Y-axis indicates a direction perpendicular to the X-direction within the boundary plane, and the Z-direction along the Z-axis indicates a direction perpendicular to the boundary plane.
　実施形態の用語における平面視とは波長板をＺ方向から視ることをいう。平面図とは波長板をＺ方向から視た図をいう。但し、これらのことは、波長板の使用時における向きを制限するものではなく、波長板の向きは任意である。 A planar view in the terminology of the embodiment means viewing the wave plate from the Z direction. A plan view is a view of the wave plate viewed from the Z direction. However, these do not limit the orientation of the wave plate when it is used, and the orientation of the wave plate is arbitrary.
　〈実施形態〉
　（波長板１の構成例）
　図１から図３は、実施形態に係る波長板１の構成を例示する図である。図１は波長板１の平面図、図２は図１のＩ－Ｉ切断線に沿う第１例の断面図、図３は図１のＩ－Ｉ切断線に沿う第２例の断面図である。 <Embodiment>
(Configuration example of wave plate 1)
1 to 3 are diagrams illustrating the configuration of the wave plate 1 according to the embodiment. 1 is a plan view of the wave plate 1, FIG. 2 is a cross-sectional view of the first example along the II section line of FIG. 1, and FIG. 3 is a cross-sectional view of the second example along the II section line of FIG. be.
　図１に示すように、波長板１は、平面視において略正方形形状を有する板状部材である。図２に示すように、波長板１は、第１の位相差層１１と、第２の位相差層１２と、を備える。換言すると、波長板１は、第１の位相差層１１と、第２の位相差層１２と、が積層された積層波長板である。 As shown in FIG. 1, the wave plate 1 is a plate-like member having a substantially square shape in plan view. As shown in FIG. 2 , the wave plate 1 includes a first retardation layer 11 and a second retardation layer 12 . In other words, the wave plate 1 is a laminated wave plate in which the first retardation layer 11 and the second retardation layer 12 are laminated.
　第１の位相差層１１および第２の位相差層１２それぞれは、境界面１０を通して入射する光に位相差を与えて出射する。第１の位相差層１１および第２の位相差層１２は、第１の位相差層１１における第２の位相差層１２側の面と、第２の位相差層１２における第１の位相差層１１側の面と、が向き合って接するように配置される。 Each of the first retardation layer 11 and the second retardation layer 12 gives a phase difference to the light incident through the boundary surface 10 and emits the light. The first retardation layer 11 and the second retardation layer 12 are the surface of the first retardation layer 11 on the side of the second retardation layer 12 and the first retardation layer 12 of the second retardation layer 12. The surface on the side of the layer 11 is arranged so as to be in contact with each other.
　図３に示すように、波長板１は、第３の位相差層１３をさらに備えることもできる。換言すると、波長板１は、第１の位相差層１１と、第２の位相差層１２と、第３の位相差層１３と、が積層された積層波長板であってもよい。 As shown in FIG. 3, the wave plate 1 may further include a third retardation layer 13. In other words, the wave plate 1 may be a laminated wave plate in which the first retardation layer 11, the second retardation layer 12, and the third retardation layer 13 are laminated.
　第３の位相差層１３は、第２の位相差層１２から出射された光を入射し、位相差を与えて出射する。第３の位相差層１３は、第２の位相差層１２における第３の位相差層１３側の面と、第３の位相差層１３における第２の位相差層１２側の面と、が向き合って接するように配置される。 The third retardation layer 13 receives the light emitted from the second retardation layer 12, gives it a phase difference, and emits it. The third retardation layer 13 has a surface of the second retardation layer 12 on the side of the third retardation layer 13 and a surface of the third retardation layer 13 on the side of the second retardation layer 12. They are arranged to face and touch each other.
　第１の位相差層１１、第２の位相差層１２および第３の位相差層１３は、それぞれ可視光に対して透光性を有する。具体的には、第１の位相差層１１、第２の位相差層１２および第３の位相差層１３は、それぞれ３００ｎｍから２０００ｎｍの波長範囲において透光性を有し、より好ましくは３８０ｎｍから１０００ｎｍの波長範囲において透光性を有する。透光性を有するとは、波長範囲４００ｎｍ～８００ｎｍで透過率５０％以上であり、好ましくは８０％以上であることをいう。透過率は例えば紫外可視分光光度計（株式会社日立ハイテクサイエンス社製品名ＵＨ－４１５０）で測定できる。 The first retardation layer 11, the second retardation layer 12, and the third retardation layer 13 are each translucent to visible light. Specifically, the first retardation layer 11, the second retardation layer 12, and the third retardation layer 13 each have translucency in the wavelength range from 300 nm to 2000 nm, more preferably from 380 nm. It has translucency in the wavelength range of 1000 nm. Having translucency means having a transmittance of 50% or more, preferably 80% or more, in a wavelength range of 400 nm to 800 nm. The transmittance can be measured, for example, with an ultraviolet-visible spectrophotometer (product name: UH-4150, manufactured by Hitachi High-Tech Science Co., Ltd.).
　本実施形態では、平面視形状が略正方形形状である波長板１を例示するが、これに限定されるものではない。波長板１は、長方形形状、円形形状、楕円形形状、又は多角形形状等の様々な平面視形状を有してもよい。 In this embodiment, the wave plate 1 having a substantially square shape in plan view is exemplified, but it is not limited to this. The wave plate 1 may have various planar shapes such as a rectangular shape, a circular shape, an elliptical shape, or a polygonal shape.
　（波長板１による偏光状態の変換例）
　図４は、波長板１による偏光状態の変換を例示する図である。図４の波長板１は、例えば図２に示す構成であり、第１の位相差層１１側から直線偏光Ｐ１を入射し、第２の位相差層１２側から円偏光Ｐ２を出射する。直線偏光Ｐ１は、Ｚ方向に進行する光である。 (Example of polarization state conversion by wave plate 1)
4A and 4B are diagrams illustrating conversion of the polarization state by the wave plate 1. FIG. The wavelength plate 1 of FIG. 4 has, for example, the configuration shown in FIG. 2, and the linearly polarized light P1 is incident from the first retardation layer 11 side and the circularly polarized light P2 is emitted from the second retardation layer 12 side. The linearly polarized light P1 is light traveling in the Z direction.
　直線偏光とは、所定の向きに電場が振動する光をいう。円偏光とは、電場の振動方向が光の進行方向に対して垂直な面内で回転し、電場が振動する向きによらず振幅が一定である光をいう。光の進行方向から視た電場の軌跡は、直線偏光では直線を描き、円偏光では円を描く。 　Linearly polarized light refers to light whose electric field oscillates in a predetermined direction. Circularly polarized light refers to light whose vibration direction of an electric field rotates in a plane perpendicular to the traveling direction of light and whose amplitude is constant regardless of the direction of vibration of the electric field. The locus of the electric field seen from the traveling direction of light draws a straight line with linearly polarized light and a circle with circularly polarized light.
　図４に示す例では、直線偏光Ｐ１は、境界面１０と略平行な平面において、Ｘ軸に対して偏光軸方位角φ０傾いた向きに電場が振動している。偏光軸方位角φ０は、例えば４５°である。但し、波長板１に対して所定の偏光軸方位角φ０において、直線偏光Ｐ１が波長板１に入射できれば、Ｘ軸に対する偏光軸方位角φ０は４５°に限定されるものではない。 In the example shown in FIG. 4, the electric field of the linearly polarized light P1 oscillates in a plane substantially parallel to the boundary surface 10 in a direction inclined by the polarization axis azimuth angle φ0 with respect to the X axis. The polarization axis azimuth angle φ0 is, for example, 45°. However, if the linearly polarized light P1 can be incident on the wavelength plate 1 at a predetermined polarization axis azimuth angle φ0 with respect to the wave plate 1, the polarization axis azimuth angle φ0 with respect to the X axis is not limited to 45°.
　電場成分Ｐ１Ｘは、直線偏光Ｐ１のＸ方向における電場振動成分である。電場成分Ｐ１Ｙは、直線偏光Ｐ１のＹ方向における電場振動成分である。波長板１は、入射する直線偏光Ｐ１のうち、例えば電場成分Ｐ１Ｙの位相を電場成分Ｐ１Ｘに対して遅れさせ、電場成分Ｐ１Ｘに対する位相差を電場成分Ｐ１Ｙに与える。 The electric field component P1X is the electric field oscillation component of the linearly polarized light P1 in the X direction. The electric field component P1Y is an electric field vibration component in the Y direction of the linearly polarized light P1. The wave plate 1 delays the phase of, for example, the electric field component P1Y of the incident linearly polarized light P1 with respect to the electric field component P1X, and gives the electric field component P1Y a phase difference with respect to the electric field component P1X.
　本実施形態では、波長板１は、入射する直線偏光Ｐ１に対し、直線偏光Ｐ１における波長の略１／４の長さに対応する位相差を与えることにより、直線偏光Ｐ１を円偏光Ｐ２に変換する。 In this embodiment, the wave plate 1 converts the linearly polarized light P1 into circularly polarized light P2 by giving a phase difference corresponding to approximately 1/4 of the wavelength of the linearly polarized light P1 to the incident linearly polarized light P1. do.
　図４では、波長板１が第１の位相差層１１側から直線偏光Ｐ１を入射し、第２の位相差層１２側から円偏光Ｐ２を出射する構成を例示したが、これに限定されるものではない。波長板１は、第２の位相差層１２側から円偏光Ｐ２を入射して第１の位相差層１１側から直線偏光Ｐ１を出射することもできる。 In FIG. 4, the wavelength plate 1 exemplifies a configuration in which the linearly polarized light P1 is incident from the first retardation layer 11 side and the circularly polarized light P2 is emitted from the second retardation layer 12 side, but it is limited to this. not a thing The wave plate 1 can also enter the circularly polarized light P2 from the second retardation layer 12 side and emit the linearly polarized light P1 from the first retardation layer 11 side.
　図４の波長板１として図２に示す構成（波長板１が第１の位相差層１１および第２の位相差層１２を備える構成）を例示したが、波長板１は第３の位相差層１３をさらに備えてもよい（図３参照）。第３の位相差層１３を備える波長板１では、直線偏光Ｐ１を入射する側から、第１の位相差層１１、第２の位相差層１２、および第３の位相差層１３がこの順に積層される。あるいは、第３の位相差層１３を備える波長板１が円偏光を入射する場合には、直線偏光Ｐ１を出射する側から第１の位相差層１１、第２の位相差層１２、および第３の位相差層１３がこの順に積層される。 Although the configuration shown in FIG. 2 (the configuration in which the wave plate 1 includes the first retardation layer 11 and the second retardation layer 12) is illustrated as the wave plate 1 in FIG. A layer 13 may also be provided (see Figure 3). In the wave plate 1 including the third retardation layer 13, the first retardation layer 11, the second retardation layer 12, and the third retardation layer 13 are arranged in this order from the side on which the linearly polarized light P1 is incident. Laminated. Alternatively, when the wave plate 1 including the third retardation layer 13 receives circularly polarized light, the first retardation layer 11, the second retardation layer 12, and the third 3 retardation layers 13 are laminated in this order.
　（液晶層の配向）
　本実施形態では、第１の位相差層１１は第１の液晶層を含み、第２の位相差層１２は第２の液晶層を含み、第３の位相差層１３は第３の液晶層を含む。第１の位相差層１１、第２の位相差層１２および第３の位相差層１３それぞれは、水平配向している液晶層、垂直配向している液晶層又はねじれ配向している液晶層のいずれかを含むことができる。ここで、液晶層の配向とは、液晶層に含まれる棒状の液晶分子の長軸が所定方向に向くことをいう。 (Orientation of liquid crystal layer)
In this embodiment, the first retardation layer 11 includes a first liquid crystal layer, the second retardation layer 12 includes a second liquid crystal layer, and the third retardation layer 13 includes a third liquid crystal layer. including. Each of the first retardation layer 11, the second retardation layer 12, and the third retardation layer 13 is a horizontally aligned liquid crystal layer, a vertically aligned liquid crystal layer, or a twisted liquid crystal layer. can contain either Here, the alignment of the liquid crystal layer means that the long axes of the rod-like liquid crystal molecules contained in the liquid crystal layer are oriented in a predetermined direction.
　図５および図６は、水平配向している液晶層を例示する図である。図５は断面図、図６は平面図である。図７は、垂直配向している液晶層を例示する断面図である。図８、図９および図１０Ａは、ねじれ配向している液晶層を例示する図である。図８は断面図、図９は光入射側から視た図８の液晶層の平面図、図１０Ａは光出射側から視た図８の液晶層の平面図である。以下、第１の位相差層１１が備える第１の液晶層を一例として説明する。 5 and 6 are diagrams illustrating horizontally aligned liquid crystal layers. 5 is a sectional view, and FIG. 6 is a plan view. FIG. 7 is a cross-sectional view illustrating a vertically aligned liquid crystal layer. 8, 9 and 10A are diagrams illustrating twisted liquid crystal layers. 8 is a cross-sectional view, FIG. 9 is a plan view of the liquid crystal layer of FIG. 8 viewed from the light incident side, and FIG. 10A is a plan view of the liquid crystal layer of FIG. 8 viewed from the light exit side. The first liquid crystal layer included in the first retardation layer 11 will be described below as an example.
　図５から図１０Ａに示すように、第１の位相差層１１は、入射側基板１１１と、入射側配向層１１２と、出射側基板１１３と、出射側配向層１１４と、第１の液晶層１１０と、を備える。入射側配向層１１２は入射側基板１１１に設けられている。出射側配向層１１４は出射側基板１１３に設けられている。第１の液晶層１１０は、入射側配向層１１２と出射側配向層１１４との間に設けられている。 As shown in FIGS. 5 to 10A, the first retardation layer 11 includes an incident-side substrate 111, an incident-side alignment layer 112, an exit-side substrate 113, an exit-side alignment layer 114, and a first liquid crystal layer. 110; The incident-side alignment layer 112 is provided on the incident-side substrate 111 . The exit-side alignment layer 114 is provided on the exit-side substrate 113 . A first liquid crystal layer 110 is provided between an entrance-side alignment layer 112 and an exit-side alignment layer 114 .
　入射側基板１１１および出射側基板１１３それぞれは、波長板１に入射する可視光に対して透光性を有するガラス又は樹脂等の材料を含んで構成される。入射側配向層１１２および出射側配向層１１４それぞれは、第１の液晶層１１０に含まれている液晶分子１１５の配向を制御するために、入射側基板１１１および出射側基板１１３の表面に設けられた微細な溝を有する。入射側配向層１１２および出射側配向層１１４は、ポリイミド等の有機薄膜や、無機蒸着膜、微小な溝構造が構成された膜等を含んで構成される。 The entrance-side substrate 111 and the exit-side substrate 113 each contain a material such as glass or resin that transmits visible light incident on the wavelength plate 1 . The incident-side alignment layer 112 and the exit-side alignment layer 114 are provided on the surfaces of the incident-side substrate 111 and the exit-side substrate 113, respectively, in order to control the alignment of the liquid crystal molecules 115 contained in the first liquid crystal layer 110. It has fine grooves. The incident-side alignment layer 112 and the exit-side alignment layer 114 include an organic thin film such as polyimide, an inorganic deposited film, a film having a minute groove structure, or the like.
　水平配向している第１の液晶層１１０では、図５に示すように、液晶分子１１５は、境界面１０と略平行である水平方向に配向する。また図６に示すように、液晶分子１１５の遅相軸１１６は、境界面１０と略平行な平面（例えばＸ－Ｙ平面）内において、Ｘ軸に対して遅相軸方位角φｃの向きに傾いて配向する。 In the horizontally aligned first liquid crystal layer 110, the liquid crystal molecules 115 are aligned in a horizontal direction substantially parallel to the interface 10, as shown in FIG. Further, as shown in FIG. 6, the slow axis 116 of the liquid crystal molecule 115 is oriented at the slow axis azimuth angle φc with respect to the X axis in a plane (for example, the XY plane) substantially parallel to the boundary surface 10. Tilt and orient.
　遅相軸とは、複屈折性を有する物質内を光が伝播する際に、光の進行速度が遅くなって位相が遅れる軸をいう。遅相軸に沿って電場が振動する光は、光の進行速度が遅くなる。 The slow axis is the axis in which the traveling speed of light slows down and the phase lags when light propagates through a material with birefringence. Light whose electric field oscillates along the slow axis slows down.
　垂直配向している第１の液晶層１１０では、図７に示すように、液晶分子１１５は、境界面１０に略垂直な方向（例えばＺ軸方向）に配向する。 In the vertically aligned first liquid crystal layer 110, as shown in FIG. 7, the liquid crystal molecules 115 are aligned in a direction substantially perpendicular to the interface 10 (for example, the Z-axis direction).
　ねじれ配向している第１の液晶層１１０では、図８に示すように、液晶分子１１５は、入射側基板１１１から出射側基板１１３に向かうにつれてねじれるように配向が変化する。換言すると、液晶分子１１５は、液晶層の厚さ方向にねじれて配向している。 In the twisted first liquid crystal layer 110, as shown in FIG. 8, the orientation of the liquid crystal molecules 115 changes so as to be twisted from the entrance side substrate 111 toward the exit side substrate 113. As shown in FIG. In other words, the liquid crystal molecules 115 are twisted and oriented in the thickness direction of the liquid crystal layer.
　液晶分子１１５は、入射側液晶分子１１５ｓと、出射側液晶分子１１５ｅと、を含んでいる。入射側液晶分子１１５ｓは、液晶分子１１５のうち、第１の位相差層１１が光を入射する側の端部に存在する液晶分子である。出射側液晶分子１１５ｅは、液晶分子１１５のうち、第１の位相差層１１が光を出射する側の端部に存在する液晶分子である。 The liquid crystal molecules 115 include incident-side liquid crystal molecules 115s and exit-side liquid crystal molecules 115e. The incident-side liquid crystal molecules 115 s are liquid crystal molecules present at the end of the liquid crystal molecules 115 on the side where the first retardation layer 11 is incident on light. The output-side liquid crystal molecules 115e are liquid crystal molecules present at the end of the liquid crystal molecules 115 on the side from which the first retardation layer 11 emits light.
　図９に示すように、入射側液晶分子１１５ｓの入射側遅相軸１１６ｓは、境界面１０と略平行な平面内において、Ｘ軸に対して遅相軸方位角φｃ_ｓの向きに傾いて配向する。図１０に示すように、出射側液晶分子１１５ｅの出射側遅相軸１１６ｅは、境界面１０と略平行な平面内において、Ｘ軸に対して遅相軸方位角φｃ_ｅの向きに傾いて配向する。 As shown in FIG. 9, the incident-side slow axes 116s of the incident-side liquid crystal molecules 115s are oriented at a slow axis azimuth angle φc_s with respect to the X-axis in a plane substantially parallel to the boundary surface 10. . As shown in FIG. 10, the output-side slow axes 116e of the output-side liquid crystal molecules 115e are aligned in a plane substantially parallel to the boundary surface 10, tilting in the direction of the slow axis azimuth φc_e with respect to the X-axis. .
　図５から図１０の説明では、第１の位相差層１１が入射側配向層１１２および出射側配向層１１４の両方を含む構成を例示したが、これに限定されるものではない。第１の位相差層１１は、入射側配向層１１２又は出射側配向層１１４のいずれか一方のみを含む構成であってもよい。さらに、第１の位相差層１１は、入射側配向層１１２又は出射側配向層１１４をいずれも含まない構成であってもよい。また、第１の位相差層１１が入射側基板１１１および出射側基板１１３の両方を含む構成を例示したが、第１の位相差層１１は、入射側基板１１１又は出射側基板１１３のいずれか一方のみを含む構成であってもよい。 5 to 10 illustrate the configuration in which the first retardation layer 11 includes both the incident-side alignment layer 112 and the exit-side alignment layer 114, but it is not limited to this. The first retardation layer 11 may include only one of the incident-side alignment layer 112 and the exit-side alignment layer 114 . Furthermore, the first retardation layer 11 may have a configuration that does not include either the incident-side alignment layer 112 or the exit-side alignment layer 114 . Also, although the first retardation layer 11 includes both the incident-side substrate 111 and the exit-side substrate 113, the first retardation layer 11 is either the incident-side substrate 111 or the exit-side substrate 113. A configuration including only one of them may be employed.
　第２の位相差層１２は、第１の位相差層１１と同様の構成であるが、第１の液晶層１１０に代えて第２の液晶層１２０を備える点が異なる。第３の位相差層１３も、第１の位相差層１１と同様の構成であるが、第１の液晶層１１０に代えて第３の液晶層１３０を備える点が異なる。第２の液晶層１２０および第３の液晶層１３０はそれぞれ液晶分子１１５を備える。 The second retardation layer 12 has the same configuration as the first retardation layer 11 , but differs in that it includes a second liquid crystal layer 120 instead of the first liquid crystal layer 110 . The third retardation layer 13 also has the same configuration as the first retardation layer 11 , but differs in that it includes a third liquid crystal layer 130 instead of the first liquid crystal layer 110 . The second liquid crystal layer 120 and the third liquid crystal layer 130 each comprise liquid crystal molecules 115 .
　図５から図１０では、第２の位相差層１２および第３の位相差層１３の符号を、括弧書きにより第１の位相差層１１の符号に併記している。図５、図７および図８では、第２の液晶層１２０および第３の液晶層１３０の符号を、括弧書きにより第１の液晶層１１０の符号に併記している。なお、第２の位相差層１２は、第２の液晶層１２０を備えれば、第１の位相差層１１と同様の構成でなくてもよい。また第３の位相差層１３は、第３の液晶層１３０を備えれば、第１の位相差層１１と同様の構成でなくてもよい。 5 to 10, the reference numerals of the second retardation layer 12 and the third retardation layer 13 are written together with the reference numerals of the first retardation layer 11 in brackets. 5, 7 and 8, the reference numerals of the second liquid crystal layer 120 and the third liquid crystal layer 130 are written together with the reference numerals of the first liquid crystal layer 110 in brackets. The second retardation layer 12 does not have to have the same configuration as the first retardation layer 11 as long as it includes the second liquid crystal layer 120 . Further, the third retardation layer 13 does not have to have the same configuration as the first retardation layer 11 as long as the third liquid crystal layer 130 is provided.
　第１の位相差層１１と第２の位相差層１２との間、あるいは第２の位相差層１２と第３の位相差層１３との間には、配向層があってもなくてもよい。 Between the first retardation layer 11 and the second retardation layer 12 or between the second retardation layer 12 and the third retardation layer 13, whether or not there is an alignment layer good.
　例えば、第１の位相差層１１、第２の位相差層１２および第３の位相差層１３は、それぞれ液晶分子１１５が所定方向に配向した状態において、紫外線を照射されることにより硬化する。波長板１は、硬化した各層を積層することにより製作される。 For example, the first retardation layer 11, the second retardation layer 12, and the third retardation layer 13 are each cured by being irradiated with ultraviolet rays in a state in which the liquid crystal molecules 115 are aligned in a predetermined direction. Wave plate 1 is fabricated by laminating cured layers.
　ここで、波長板１における入射側配向層１１２及び出射側配向層１１４等の配向層は、第１の液晶層１１０等の液晶層に接する面に複数の溝を有してもよい。図１０Ｂ（Ａ）は、透明基材４と配向層５の一例を示す斜視図であり、図１０Ｂ（Ｂ）は、図１０Ｂ（Ａ）に示す配向層５によって配向された液晶分子６１の一例を示す斜視図である。図１０Ｃは、複数の溝を有する波長板１ａの構成の一例を示す図であり、図１０Ｃ（Ａ）は微視的に視た断面図、図１０Ｃ（Ｂ）は巨視的に視た断面図である。 Here, the alignment layers such as the incident-side alignment layer 112 and the exit-side alignment layer 114 in the wavelength plate 1 may have a plurality of grooves on the surface in contact with the liquid crystal layer such as the first liquid crystal layer 110 . 10B(A) is a perspective view showing an example of the transparent substrate 4 and the alignment layer 5, and FIG. 10B(B) is an example of liquid crystal molecules 61 aligned by the alignment layer 5 shown in FIG. 10B(A). It is a perspective view showing the. FIG. 10C is a diagram showing an example of the configuration of a wavelength plate 1a having a plurality of grooves, FIG. 10C(A) is a microscopic cross-sectional view, and FIG. 10C(B) is a macroscopic cross-sectional view. is.
　透明基材４は基板の一例に対応し、図１０Ｂ、Ｃにおける透明基材４のＸ方向及びＹ方向に沿った面は、基板の面の一例に対応する。複数の溝は、Ｚ軸方向視で互いに平行である。複数の溝は、樹脂組成物の塗布後に、例えばインプリント法によって形成される。複数の溝は、例えばストライプパターン状に形成される。 The transparent base material 4 corresponds to an example of the substrate, and the surfaces of the transparent base material 4 along the X direction and the Y direction in FIGS. 10B and 10C correspond to an example of the surface of the substrate. The plurality of grooves are parallel to each other when viewed in the Z-axis direction. A plurality of grooves are formed by, for example, an imprint method after applying the resin composition. A plurality of grooves are formed, for example, in a stripe pattern.
　図１０Ｂにおいて、仮に波長板１を地面に対して垂直におき、Ｚ軸を入射光および地面に対して平行方向とする配置とした場合、Ｚ軸と同じく地面に平行な方向がＸ軸であり、地面に対して垂直な方向がＹ軸方向である。インプリント法で溝５１を形成する場合、ラビング法で溝５１を形成する場合に比べて、溝５１の寸法及び形状を精度良く制御でき、異物の混入も軽減できる。 In FIG. 10B, if the wave plate 1 is placed perpendicular to the ground and the Z axis is parallel to the incident light and the ground, the direction parallel to the ground is the X axis as well as the Z axis. , the direction perpendicular to the ground is the Y-axis direction. When the grooves 51 are formed by imprinting, the dimensions and shape of the grooves 51 can be controlled with high precision, and contamination by foreign matter can be reduced as compared with the case of forming the grooves 51 by the rubbing method.
　透明基材４の厚みＴ１は、例えば０．０１ｍｍ～０．３ｍｍであり、好ましくは０．０２ｍｍ～０．１ｍｍであり、より好ましくは０．０３ｍｍ～０．０９ｍｍである。Ｔ１が上記範囲内であれば、曲げ加工性と、ハンドリング性とを両立できる。 The thickness T1 of the transparent substrate 4 is, for example, 0.01 mm to 0.3 mm, preferably 0.02 mm to 0.1 mm, more preferably 0.03 mm to 0.09 mm. If T1 is within the above range, both bending workability and handleability can be achieved.
　配向層５は、液晶層６の液晶分子を配向させる。配向層５の液晶層６と接する表面１２１には、例えば、互いに平行な複数の溝５１が形成されている。複数の溝５１は、例えばストライプパターン状に形成される。Ｚ軸方向視で、溝５１の長手方向がＸ軸方向であり、溝５１の幅方向がＹ軸方向である。 The alignment layer 5 orients the liquid crystal molecules of the liquid crystal layer 6 . For example, a plurality of parallel grooves 51 are formed on the surface 121 of the alignment layer 5 in contact with the liquid crystal layer 6 . The plurality of grooves 51 are formed, for example, in a stripe pattern. When viewed in the Z-axis direction, the longitudinal direction of the groove 51 is the X-axis direction, and the width direction of the groove 51 is the Y-axis direction.
　溝５１の平行度は、例えば０°～５°であり、好ましくは０°～１°である。溝５１の平行度とは、Ｚ軸方向視で、隣り合う２つの溝５１のなす角の最大値である。隣り合う２つの溝５１のなす角が０°に近いほど、平行度がよい。 The parallelism of the grooves 51 is, for example, 0° to 5°, preferably 0° to 1°. The parallelism of the grooves 51 is the maximum value of the angle formed by two adjacent grooves 51 when viewed in the Z-axis direction. The closer the angle between two adjacent grooves 51 to 0°, the better the parallelism.
　溝５１の深さＤは、例えば３ｎｍ～５００ｎｍであり、好ましくは５ｎｍ～３００ｎｍであり、より好ましくは１０ｎｍ～１５０ｎｍである。Ｄが３ｎｍ以上であれば、配向規制力が大きく、液晶分子が配向されやすい。一方、Ｄが５００ｎｍ以下であれば、モールドの凹凸パターンの転写性が良い。また、Ｄが５００ｎｍ以下であれば、回折光も発生しにくい。 The depth D of the groove 51 is, for example, 3 nm to 500 nm, preferably 5 nm to 300 nm, more preferably 10 nm to 150 nm. When D is 3 nm or more, the alignment regulating force is large, and the liquid crystal molecules are easily aligned. On the other hand, when D is 500 nm or less, the transferability of the concave-convex pattern of the mold is good. Moreover, when D is 500 nm or less, diffracted light is less likely to occur.
　例えば、位相差層の中心における溝５１の深さは、位相差層の外周における溝５１の深さより深くなっていてもよいし、浅くなっていてもよい。溝５１の深さＤは、例えばインプリント法で使用されるモールドの凹凸パターンで調整される。また、溝５１の深さＤは、配向層５の表面を部分的にアッシングすることでも調整できる。 For example, the depth of the groove 51 at the center of the retardation layer may be deeper or shallower than the depth of the groove 51 at the outer periphery of the retardation layer. The depth D of the grooves 51 is adjusted, for example, by the concave-convex pattern of the mold used in the imprint method. The depth D of the groove 51 can also be adjusted by partially ashing the surface of the alignment layer 5 .
　溝５１の深さＤが深いほど、液晶層６の液晶分子の配向規制力が大きく、（ｎｅ－ｎо）が大きい。（ｎｅ－ｎо）の増大によるリタデーションの増大で、ｔの減少によるリタデーションの減少を打ち消すことができ、リタデーションのバラツキを抑制できる。（ｎｅ－ｎо）、リタデーション、およびｔについては後述する。 The greater the depth D of the groove 51, the greater the alignment control force of the liquid crystal molecules of the liquid crystal layer 6, and the greater the (ne-no). An increase in retardation due to an increase in (ne-no) can cancel a decrease in retardation due to a decrease in t, and retardation variations can be suppressed. (ne-no), retardation, and t will be described later.
　例えば、位相差層を形成する面が曲面を含む３次元構造物である場合、位相差層の中央における溝５１の深さＤが、位相差層の周縁における溝５１の深さＤよりも深い。位相差層の周縁から中央にかけて、溝５１の深さＤが連続的又は段階的に深くなる。従って、リタデーションが同心円状にシフトするのを抑制でき、色調が同心円状にシフトするのを抑制できる。この深さ分布については曲面が凹か凸、曲面の形状などにより適宜変更できる。また、上述のインプリント法などで作成することができる。 For example, when the surface forming the retardation layer is a three-dimensional structure including a curved surface, the depth D of the grooves 51 at the center of the retardation layer is deeper than the depth D of the grooves 51 at the periphery of the retardation layer. . The depth D of the groove 51 increases continuously or stepwise from the periphery to the center of the retardation layer. Therefore, it is possible to suppress the retardation from shifting concentrically, and it is possible to suppress the color tone from shifting concentrically. This depth distribution can be appropriately changed depending on whether the curved surface is concave or convex, the shape of the curved surface, and the like. Moreover, it can be created by the above-described imprint method or the like.
　溝５１の向きも中心と外周、また面内の場所ごとに適宜変更することが可能である。例えば中心に対して外周の溝５１を傾けることで曲面に対して偏光が入射する際の偏光の向きを補正することができる。これについても上述のインプリント法で作成することができる。 The orientation of the grooves 51 can also be appropriately changed between the center and the outer periphery, as well as for each in-plane location. For example, by tilting the grooves 51 on the outer periphery with respect to the center, the direction of polarized light incident on the curved surface can be corrected. This can also be produced by the imprint method described above.
　溝５１の開口幅Ｗは、例えば５ｎｍ～８００ｎｍ、好ましくは２０ｎｍ～３００ｎｍでより好ましくは３０ｎｍ～１５０ｎｍである。 The opening width W of the groove 51 is, for example, 5 nm to 800 nm, preferably 20 nm to 300 nm, more preferably 30 nm to 150 nm.
　溝５１のピッチｐは、例えば１０ｎｍ～６００ｎｍであり、好ましくは５０ｎｍ～３００ｎｍであり、より好ましくは８０ｎｍ～２００ｎｍである。ｐが６００ｎｍ以下であれば、配向規制力が大きく、液晶分子が配向されやすい。また、ｐが３００ｎｍ以下であれば、回折光が発生しにくい。一方、ｐが１０ｎｍ以上であれば、モールドの凹凸パターンの形成が容易である。 The pitch p of the grooves 51 is, for example, 10 nm to 600 nm, preferably 50 nm to 300 nm, more preferably 80 nm to 200 nm. When p is 600 nm or less, the alignment control force is large and the liquid crystal molecules are easily aligned. Moreover, when p is 300 nm or less, diffracted light is less likely to occur. On the other hand, if p is 10 nm or more, it is easy to form the uneven pattern of the mold.
　溝５１の開口幅Ｗは、例えば５ｎｍ～５００ｎｍであり、好ましくは２０ｎｍ～２００ｎｍであり、より好ましくは３０ｎｍ～１５０ｎｍである。なお、ピッチｐと開口幅Ｗの差（ｐ－Ｗ：ｐ＞Ｗ）が、溝５１同士の間隔（２つの溝５１を隔てる凸部の幅）である。 The opening width W of the groove 51 is, for example, 5 nm to 500 nm, preferably 20 nm to 200 nm, more preferably 30 nm to 150 nm. The difference between the pitch p and the opening width W (p−W: p>W) is the interval between the grooves 51 (the width of the protrusion separating the two grooves 51).
　溝５１の長手方向（Ｘ軸方向）に垂直な断面は、矩形であっても三角形であっても台形であってもよい。溝５１は、深さが浅くなるほど、幅が広くなる。この場合、インプリント法で使用されるモールドの剥離が容易である。 A cross section perpendicular to the longitudinal direction (X-axis direction) of the groove 51 may be rectangular, triangular, or trapezoidal. The groove 51 becomes wider as the depth becomes shallower. In this case, it is easy to peel off the mold used in the imprint method.
　溝構造を形成する材料としては、例えば光硬化性樹脂又は熱硬化性樹脂等のエネルギー硬化性樹脂を含む。特に加工性、耐熱性及び耐久性に優れる点から光硬化性樹脂が好ましい。光硬化性樹脂組成物は、例えば、単量体、光重合開始剤、溶剤、及び必要に応じた添加剤（例えば界面活性剤、重合禁止剤）を含む組成物である。 Materials for forming the groove structure include, for example, energy curable resins such as photocurable resins and thermosetting resins. In particular, photocurable resins are preferred because they are excellent in workability, heat resistance and durability. The photocurable resin composition is, for example, a composition containing a monomer, a photopolymerization initiator, a solvent, and optional additives (eg, surfactant, polymerization inhibitor).
　配向層５の厚みＴ２は、例えば１ｎｍ～２０μｍであり、好ましくは５０ｎｍ～１０μｍであり、より好ましくは１００ｎｍ～５μｍである。配向層５の厚みＴ２は、透明基材４の配向層５が形成される表面４ａの各点における法線方向に測定する。配向層５が溝５１を有する場合、本明細書において、配向層５の厚みＴ２とは、溝５１の底と透明基材４の表面４ａとの間隔のことである。配向層５の厚みＴ２が２０μｍ以下であれば加工性がよい。 The thickness T2 of the alignment layer 5 is, for example, 1 nm to 20 μm, preferably 50 nm to 10 μm, more preferably 100 nm to 5 μm. The thickness T2 of the orientation layer 5 is measured in the normal direction at each point on the surface 4a of the transparent substrate 4 on which the orientation layer 5 is formed. When the alignment layer 5 has the grooves 51 , the thickness T2 of the alignment layer 5 herein means the distance between the bottom of the grooves 51 and the surface 4 a of the transparent substrate 4 . If the thickness T2 of the orientation layer 5 is 20 μm or less, workability is good.
　配向層５のガラス転移点Ｔｇ＿ａｌは、例えば４０℃～２００℃であり、好ましくは５０℃～１６０℃であり、より好ましくは７０℃～１５０℃である。Ｔｇ＿ａｌが上記範囲内であれば、曲げ加工性が良い。配向層５のガラス転移点は、例えばティー・エイ・インスツルメント・ジャパン株式会社の熱機械分析（ＴＭＡ　Ｑ４００）により測定される。 The glass transition point Tg_al of the alignment layer 5 is, for example, 40°C to 200°C, preferably 50°C to 160°C, more preferably 70°C to 150°C. If Tg_al is within the above range, bending workability is good. The glass transition point of the alignment layer 5 is measured, for example, by thermal mechanical analysis (TMA Q400) of TA Instruments Japan.
　液晶層６の厚みＴ３は、光の波長と、位相差と、Δｎ（Δｎ＝ｎｅ－ｎｏ）とに基づいて決められる。例えば、光の波長が５４３ｎｍであり、位相差が１／４波長である場合、Ｒｄは１３６ｎｍである。Ｒｄが１３６ｎｍであってΔｎが０．１である場合、液晶層６の厚みＴ３は１３６０ｎｍである。 The thickness T3 of the liquid crystal layer 6 is determined based on the wavelength of light, phase difference, and Δn (Δn=ne−no). For example, if the wavelength of light is 543 nm and the phase difference is 1/4 wavelength, Rd is 136 nm. When Rd is 136 nm and Δn is 0.1, the thickness T3 of the liquid crystal layer 6 is 1360 nm.
　液晶層６の厚みＴ３は、上記の通り、光の波長と、位相差と、Δｎとに基づいて決められ、特に限定されないが、例えば０．３μｍ～３０μｍであり、好ましくは０．５μｍ～２０μｍであり、より好ましくは０．８μｍ～１０μｍである。Ｔ３が０．３μｍ以上であれば、目的の位相差が得られやすい。また、Ｔ３が３０μｍ以下であれば、液晶分子が配向しやすい。 The thickness T3 of the liquid crystal layer 6 is determined based on the wavelength of light, the phase difference, and Δn as described above, and is not particularly limited, but is, for example, 0.3 μm to 30 μm, preferably 0.5 μm to 20 μm. and more preferably 0.8 μm to 10 μm. When T3 is 0.3 μm or more, a desired phase difference can be easily obtained. Further, when T3 is 30 μm or less, the liquid crystal molecules are easily aligned.
　なお、液晶層６は、１／４波長板には限定されず、１／２波長板等位相差板として目的に沿うものであればどのような位相差であってもよい。また、液晶層６は、直交する２つの直線偏光成分間の位相をずらす位相差層には限定されず、二軸性位相差板などを用いた補償層であってもよい。補償層は、例えば、液晶ディスプレイの異なる視野角で生じる位相差を補正し、所定の視野角内で画面のコントラストを向上させる。 It should be noted that the liquid crystal layer 6 is not limited to a 1/4 wavelength plate, and may have any retardation such as a 1/2 wavelength plate as long as it meets the purpose. Moreover, the liquid crystal layer 6 is not limited to a retardation layer that shifts the phase between two orthogonal linearly polarized light components, and may be a compensation layer using a biaxial retardation plate or the like. The compensation layer, for example, corrects the phase difference that occurs at different viewing angles of the liquid crystal display and improves the contrast of the screen within a given viewing angle.
　液晶層６の厚みＴ３は、透明基材４の表面４ａの各点における法線方向に測定する。配向層５が溝５１を有する場合、本明細書において、液晶層６の厚みＴ３とは、溝５１の底と液晶層６の配向層５とは反対側の表面との間隔のことである。 The thickness T3 of the liquid crystal layer 6 is measured in the normal direction at each point on the surface 4a of the transparent substrate 4. When the alignment layer 5 has the grooves 51 , the thickness T3 of the liquid crystal layer 6 herein means the distance between the bottom of the grooves 51 and the surface of the liquid crystal layer 6 opposite the alignment layer 5 .
　液晶層６のガラス転移点Ｔｇ＿ａは、例えば５０℃～２００℃であり、好ましくは８０℃～１８０℃である。Ｔｇ＿ａが上記範囲内であれば、曲げ加工性が良い。液晶層６のガラス転移点Ｔｇ＿ａは、例えばＴＭＡで測定される。 The glass transition point Tg_a of the liquid crystal layer 6 is, for example, 50°C to 200°C, preferably 80°C to 180°C. If Tg_a is within the above range, bending workability is good. The glass transition point Tg_a of the liquid crystal layer 6 is measured by TMA, for example.
　波長板１の厚みＴ４は、特に限定されないが、例えば０．０１１ｍｍ～０．３０１ｍｍであり、好ましくは０．０２１ｍｍ～０．１０１ｍｍであり、より好ましくは０．０３１ｍｍ～０．０９１ｍｍである。波長板１の厚みＴ４は、透明基材４の表面４ａの各点における法線方向に測定する。 Although the thickness T4 of the wave plate 1 is not particularly limited, it is, for example, 0.011 mm to 0.301 mm, preferably 0.021 mm to 0.101 mm, and more preferably 0.031 mm to 0.091 mm. The thickness T4 of the wave plate 1 is measured in the normal direction at each point on the surface 4a of the transparent substrate 4. As shown in FIG.
　なお、波長板１は、図示しないが、液晶層６とは遅相軸の方向が異なる液晶層を含んでもよく、当該液晶層の液晶分子を配向させる配向層を更に含んでもよい。つまり、波長板１は、広帯域位相差板であってもよい。波長板１に含まれる液晶層の数は、２つ以上であってもよい。 Although not shown, the wave plate 1 may include a liquid crystal layer having a slow axis direction different from that of the liquid crystal layer 6, and may further include an alignment layer for aligning the liquid crystal molecules of the liquid crystal layer. That is, the wave plate 1 may be a broadband retardation plate. The number of liquid crystal layers included in wave plate 1 may be two or more.
　例えば、配向層が液晶層に接する面に、Ｚ軸方向視で互いに平行な複数の溝を有する波長板１ａは、以下の構成を有することができる（図１０Ｂ、Ｃ参照）。すなわち、波長板１ａは、第１の位相差層１１、第２の位相差層１２および第３の位相差層１３、これらを支持する透明基材４と、を備える。第１の位相差層１１は、第１の液晶層１１０を含む。第２の位相差層１２は、第２の液晶層１２０を含む。第３の位相差層１３は、第３の液晶層１３０を含む。第１の液晶層１１０および第３の液晶層１３０は、透明基材４の基板面に対して液晶分子６１が平行方向に配向する。第１の液晶層１１０および第３の液晶層１３０は、いずれも厚さ方向に液晶分子６１がねじれて配向する。第２の液晶層１２０は、厚さ方向に液晶分子が垂直に配向する。第１の位相差層および第３の位相差層は、いずれも微小な１次元格子状の溝からなる配向層５（１１４，１３４）を含む。波長板１ａでは、直線偏光を入射させる側から、第１の位相差層１１、第２の位相差層１２、第３の位相差層１３の順に積層される。 For example, a wave plate 1a having a plurality of grooves parallel to each other when viewed in the Z-axis direction on the surface where the alignment layer contacts the liquid crystal layer can have the following configuration (see FIGS. 10B and 10C). That is, the wave plate 1a includes a first retardation layer 11, a second retardation layer 12, a third retardation layer 13, and a transparent substrate 4 that supports them. The first retardation layer 11 includes a first liquid crystal layer 110 . The second retardation layer 12 includes a second liquid crystal layer 120 . The third retardation layer 13 includes a third liquid crystal layer 130 . In the first liquid crystal layer 110 and the third liquid crystal layer 130 , the liquid crystal molecules 61 are oriented parallel to the substrate surface of the transparent base material 4 . In both the first liquid crystal layer 110 and the third liquid crystal layer 130, the liquid crystal molecules 61 are twisted and aligned in the thickness direction. The liquid crystal molecules of the second liquid crystal layer 120 are vertically aligned in the thickness direction. Each of the first retardation layer and the third retardation layer includes an alignment layer 5 (114, 134) composed of fine one-dimensional lattice-like grooves. In the wave plate 1a, the first retardation layer 11, the second retardation layer 12, and the third retardation layer 13 are laminated in this order from the linearly polarized incident side.
　なお、図１０Ｃ（Ｂ）はイメージ図であり、液晶層の液晶分子の配向方向と配向層の溝の方向はこれに限定されるものではない。 Note that FIG. 10C(B) is an image diagram, and the alignment direction of the liquid crystal molecules in the liquid crystal layer and the direction of the grooves in the alignment layer are not limited to this.
　波長板１ａは、以下の構成を有してもよい。第３の位相差層１３と第２の位相差層１２との間に、粘着層２０１があってもよい。粘着層は、ＯＣＡ、紫外線硬化樹脂などで形成される。 The wave plate 1a may have the following configuration. An adhesive layer 201 may be provided between the third retardation layer 13 and the second retardation layer 12 . The adhesive layer is formed of OCA, ultraviolet curable resin, or the like.
　また、第２の位相差層１２は、配向層を有していてもよい。配向層は、図５等に図示されるように入射側配向層および出射側配向層が設けられてもよく、入射側配向層および出射側配向層のいずれか一方のみが設けられていてもよい。 Also, the second retardation layer 12 may have an orientation layer. The alignment layer may be provided with an incident-side alignment layer and an exit-side alignment layer as shown in FIG. .
　波長板１ａは、以下の構成を有してもよい。すなわち、透明基材４に対して液晶分子１１５（６１）が平行方向に配向している場合を０°、透明基材４の法線に対して液晶分子１１５（６１）が平行方向に配向している場合を９０°と定義したチルト角が０°以上２°未満である。第１の液晶層１１０および第３の液晶層１３０の液晶分子１１５（６１）のねじれの方向が同一であり、第１の液晶層１１０、第２の液晶層１２０、第３の液晶層１３０はいずれも正分散の液晶分子１１５（６１）からなる。透明基材４の三次元座標系において、第１の位相差層１１における第３の位相差層１３側の遅相軸と、第２の位相差層１２の遅相軸と、のなす角は９０°である。透明基材４の三次元座標系において、第３の位相差層１３における第１の位相差層１１側の遅相軸と、第２の位相差層１２の遅相軸と、のなす角は９０°である。透明基材４の三次元座標系において、第３の位相差層１３における第１の位相差層１１側の遅相軸と、第１の位相差層１１における第３の位相差層１３側の遅相軸と、のなす角は０°より大きく２°未満である。透明基材４の三次元座標系は、透明基材４の厚さ方向と、該厚さ方向に垂直な面内において直交する２つの方向と、の合計３つの方向により定義される座標系を意味する。 The wave plate 1a may have the following configuration. That is, when the liquid crystal molecules 115 (61) are oriented parallel to the transparent base material 4, the liquid crystal molecules 115 (61) are oriented parallel to the normal to the transparent base material 4. The tilt angle defined as 90° is 0° or more and less than 2°. The twist directions of the liquid crystal molecules 115 (61) of the first liquid crystal layer 110 and the third liquid crystal layer 130 are the same, and the first liquid crystal layer 110, the second liquid crystal layer 120, and the third liquid crystal layer 130 Both are composed of positively dispersed liquid crystal molecules 115 (61). In the three-dimensional coordinate system of the transparent substrate 4, the angle formed by the slow axis of the first retardation layer 11 on the side of the third retardation layer 13 and the slow axis of the second retardation layer 12 is 90°. In the three-dimensional coordinate system of the transparent substrate 4, the angle formed by the slow axis of the third retardation layer 13 on the first retardation layer 11 side and the slow axis of the second retardation layer 12 is 90°. In the three-dimensional coordinate system of the transparent substrate 4, the slow axis of the third retardation layer 13 on the first retardation layer 11 side and the third retardation layer 13 side of the first retardation layer 11 The angle formed with the slow axis is greater than 0° and less than 2°. The three-dimensional coordinate system of the transparent base material 4 is a coordinate system defined by a total of three directions: the thickness direction of the transparent base material 4 and two orthogonal directions in a plane perpendicular to the thickness direction. means.
　さらに、波長板１ａは、成形時膜厚変化がない場合には、第１の位相差層１１の波長５５０ｎｍにおける面内リタデーションが２８０ｎｍ以上３００ｎｍ以下であり、第２の位相差層１２の波長５５０ｎｍにおける面内リタデーションが１５ｎｍ以下であり、第３の位相差層１３の波長５５０ｎｍにおける面内リタデーションが１３０ｎｍ以上１５０ｎｍ以下である。一方、波長板１ａは、成形時膜厚変化がある場合には、第１の位相差層１１の波長５５０ｎｍにおける面内リタデーションが３１０ｎｍ以上３３５ｎｍ以下であり、第２の位相差層１２の波長５５０ｎｍにおける面内リタデーションが１７ｎｍ以下であり、第３の位相差層１３の波長５５０ｎｍにおける面内リタデーションが１４０ｎｍ以上１７ｎｍ以下である。第１の位相差層１１及び第３の位相差層１３のＲｔｈが正である。第２の位相差層１２のＲｔｈが負であり、好ましくは－１５０～－８０ｎｍである。 Furthermore, the wave plate 1a has an in-plane retardation of 280 nm or more and 300 nm or less at a wavelength of 550 nm of the first retardation layer 11 when the film thickness does not change during molding, and the wavelength of the second retardation layer 12 is 550 nm. is 15 nm or less, and the in-plane retardation of the third retardation layer 13 at a wavelength of 550 nm is 130 nm or more and 150 nm or less. On the other hand, in the wave plate 1a, when the film thickness changes during molding, the in-plane retardation of the first retardation layer 11 at a wavelength of 550 nm is 310 nm or more and 335 nm or less, and the second retardation layer 12 has a wavelength of 550 nm. is 17 nm or less, and the in-plane retardation of the third retardation layer 13 at a wavelength of 550 nm is 140 nm or more and 17 nm or less. Rth of the first retardation layer 11 and the third retardation layer 13 is positive. The Rth of the second retardation layer 12 is negative, preferably -150 to -80 nm.
　また、波長板１ａは、３次元構造物３０１を含んでもよい。３次元構造物３０１は曲面を有してもよい。３次元構造物３０１が曲面を有する場合には、３次元構造物３０１の中心から１０ｍｍの位置の透明基材４の厚みは、３次元構造物３０１の中心における透明基材４の厚みの１.０倍以上１.２倍以下にすることができる。また、波長板１ａは、３次元構造物３０１の中心から１３ｍｍの位置の透明基材４の厚みは、３次元構造物３０１の中心における透明基材４の厚みの１.０倍以上１.２倍以下することもできる。さらに、３次元構造物３０１の中心から１５ｍｍの位置の透明基材４の厚みは、３次元構造物３０１の中心における透明基材４の厚みの１.０倍以上１.２倍以下にすることもできる。 Also, the wave plate 1 a may include a three-dimensional structure 301 . The three-dimensional structure 301 may have curved surfaces. When the three-dimensional structure 301 has a curved surface, the thickness of the transparent substrate 4 at the position 10 mm from the center of the three-dimensional structure 301 is 1.0 mm of the thickness of the transparent substrate 4 at the center of the three-dimensional structure 301 . It can be 0 times or more and 1.2 times or less. Further, in the wavelength plate 1a, the thickness of the transparent base material 4 at the position 13 mm from the center of the three-dimensional structure 301 is 1.0 times or more the thickness of the transparent base material 4 at the center of the three-dimensional structure 301 and 1.2 times. It can also be doubled or less. Furthermore, the thickness of the transparent substrate 4 at a position 15 mm from the center of the three-dimensional structure 301 should be 1.0 times or more and 1.2 times or less than the thickness of the transparent substrate 4 at the center of the three-dimensional structure 301. can also
　また、波長板１ａは、以下の構成を有してもよい。 Also, the wave plate 1a may have the following configuration.
　第１の位相差層は、図５等に示される、入射側基板、入射側配向層、出射側配向層、および出射側基板のうち、一以上を有してもよい。 The first retardation layer may have one or more of the incident-side substrate, the incident-side orientation layer, the exit-side orientation layer, and the exit-side substrate shown in FIG. 5 and the like.
　第３の位相差層は、図５等に示される、入射側基板、入射側配向層、出射側配向層、および出射側基板のうち、一以上を有してもよい。 The third retardation layer may have one or more of the incident-side substrate, the incident-side alignment layer, the exit-side alignment layer, and the exit-side substrate shown in FIG. 5 and the like.
　第２の位相差層は、図５等に示される、入射側基板、入射側配向層、出射側配向層、および出射側基板のうち、一以上を有してもよい。 The second retardation layer may have one or more of the incident-side substrate, the incident-side alignment layer, the exit-side alignment layer, and the exit-side substrate shown in FIG. 5 and the like.
　以降では、波長板１について説明するが、波長板１を波長板１ａに置換可能である。 Although the wave plate 1 will be described below, the wave plate 1 can be replaced with the wave plate 1a.
　（液晶層の波長分散性）
　図１１は、波長板１が備える液晶層の波長分散性の一例を説明する図である。図１１に示すグラフにおいて、横軸は、波長板１が入射する光の波長λを示し、縦軸は、リタデーションＲを示している。実線５３は逆分散性を表し、破線５２は正分散性を表している。 (Wavelength dispersion of liquid crystal layer)
FIG. 11 is a diagram illustrating an example of the wavelength dispersion of the liquid crystal layer included in the wavelength plate 1. FIG. In the graph shown in FIG. 11, the horizontal axis indicates the wavelength λ of light incident on the wavelength plate 1, and the vertical axis indicates the retardation R. In FIG. Solid line 53 represents inverse dispersion and dashed line 52 represents positive dispersion.
　逆分散性とは、波長が長くなるほどリタデーションが大きくなる性質をいう。正分散性とは、波長が短くなるほどリタデーションが大きくなる性質をいう。 "Reverse dispersion" refers to the property that the longer the wavelength, the larger the retardation. Positive dispersion means the property that the shorter the wavelength, the larger the retardation.
　液晶層を構成する材料を決定することにより、液晶層が逆分散性又は正分散性のいずれを有するかが決定され、波長λとリタデーションＲとの関係を示す性質が決定される。 By determining the material constituting the liquid crystal layer, it is determined whether the liquid crystal layer has reverse dispersion or positive dispersion, and the property indicating the relationship between the wavelength λ and the retardation R is determined.
　（各位相差層の構成例）
　本実施形態に係る波長板１では、上述した水平配向、垂直配向又はねじれ配向の液晶層、あるいは正分散性又は逆分散性を有する液晶層を用いて、第１の位相差層１１、第２の位相差層１２および第３の位相差層１３それぞれが構成される。 (Configuration example of each retardation layer)
In the wavelength plate 1 according to the present embodiment, the above-described horizontally aligned, vertically aligned, or twisted liquid crystal layer, or a liquid crystal layer having normal dispersion or reverse dispersion is used to form the first retardation layer 11, the second , the retardation layer 12 and the third retardation layer 13 are respectively formed.
　波長板１では特に、第１の位相差層１１に含まれる第１の液晶層１１０および第２の位相差層１２に含まれる第２の液晶層１２０の少なくとも一以上は、厚さ方向に液晶分子１１５がねじれて配向している。第１の位相差層１１における第２の位相差層１２側の出射側遅相軸１１６ｅと、第２の位相差層１２における第１の位相差層１１側の入射側遅相軸１１６ｓと、がなす遅相軸方位角Δφｃは１０°以上である。遅相軸方位角Δφｃは、遅相軸が3次元的になす角度を意味する。遅相軸方位角Δφｃは１３°以上が好ましく、１５°以上がより好ましい。また、遅相軸方位角Δφｃは２０°以上でもよく、５０°以上でもよく、９０°でもよい。 Particularly in the wave plate 1, at least one of the first liquid crystal layer 110 included in the first retardation layer 11 and the second liquid crystal layer 120 included in the second retardation layer 12 has liquid crystals in the thickness direction. Molecules 115 are twisted and oriented. An output-side slow axis 116e on the side of the second retardation layer 12 in the first retardation layer 11, and an incident-side slow axis 116s on the side of the first retardation layer 11 in the second retardation layer 12, is 10° or more. The slow axis azimuth angle Δφc means an angle formed by the slow axis three-dimensionally. The slow axis azimuth angle Δφc is preferably 13° or more, more preferably 15° or more. Also, the slow axis azimuth angle Δφc may be 20° or more, 50° or more, or 90°.
　（波長板１のリタデーションおよび面内リタデーション）
　次に、波長板１のリタデーションおよび面内リタデーションについて説明する。厚さ方向のリタデーションについても説明する。以下、波長５５０ｎｍの場合について説明する。 (Retardation and in-plane retardation of wave plate 1)
Next, the retardation and in-plane retardation of the wave plate 1 will be explained. Retardation in the thickness direction will also be described. The case of a wavelength of 550 nm will be described below.
　ここで、リタデーションとは、遅相軸に沿って電場が振動する光に対する異常光屈折率ｎｅ、遅相軸と直交する方向に沿って電場が振動する光に対する常光屈折率ｎоの差（ｎｅ－ｎо）と層の厚みｔの積をいい、（ｎｅ－ｎо）×ｔで表される。 Here, the retardation is the difference (ne- no) and the layer thickness t, and is represented by (ne-no) x t.
　第１の位相差層１１のリタデーションＲ１は、（ｎ１ｅ－ｎ１о）×ｔ１で表される。第１の位相差層１１の遅相軸に沿って電場が振動する光に対する屈折率をｎ１ｅとする。第１の位相差層１１の遅相軸と直交する方向に沿って電場が振動する光に対する屈折率をｎ１ｏとする。第１の位相差層１１の厚さをｔ１とする。 The retardation R1 of the first retardation layer 11 is represented by (n1e-n1?) x t1. Let n1e be the refractive index of the first retardation layer 11 for light whose electric field oscillates along the slow axis. Let n1o be the refractive index for light whose electric field oscillates along the direction perpendicular to the slow axis of the first retardation layer 11 . Let t1 be the thickness of the first retardation layer 11 .
　第２の位相差層１２のリタデーションＲ２は、（ｎ２ｅ－ｎ２о）×ｔ２で表される。第２の位相差層１２の遅相軸に沿って電場が振動する光に対する屈折率をｎ２ｅとする。第２の位相差層１２の遅相軸と直交する方向に沿って電場が振動する光に対する屈折率をｎ２ｏとする。第２の位相差層１２の厚さをｔ２とする。 The retardation R2 of the second retardation layer 12 is represented by (n2e-n2?) x t2. Let n2e be the refractive index of the second retardation layer 12 for light whose electric field oscillates along the slow axis. Let n2o be the refractive index for light whose electric field oscillates along the direction orthogonal to the slow axis of the second retardation layer 12 . Let t2 be the thickness of the second retardation layer 12 .
　第３の位相差層１３のリタデーションＲ３は、（ｎ３ｅ－ｎ３о）×ｔ３で表される。第３の位相差層１３の遅相軸に沿って電場が振動する光に対する屈折率をｎ３ｅとする。第３の位相差層１３の遅相軸と直交する方向に沿って電場が振動する光に対する屈折率をｎ３ｏとする。第３の位相差層１３の厚さをｔ３とする。 The retardation R3 of the third retardation layer 13 is represented by (n3e-n3?) x t3. Let n3e be the refractive index of the third retardation layer 13 for light whose electric field oscillates along the slow axis. Let n3o be the refractive index for light whose electric field oscillates along the direction perpendicular to the slow axis of the third retardation layer 13 . Let t3 be the thickness of the third retardation layer 13 .
　第１の位相差層１１の面内リタデーションＲｅ１は、（ｎ１ｘ－ｎ１ｙ）×ｔ１の絶対値により表される。第１の位相差層１１面（例えば図２および図３のＸ－Ｙ平面）に平行であって、互いに直行する方向の屈折率をｎ１ｘおよびｎ１ｙとする。第１の位相差層１１面に垂直な方向の屈折率をｎ１ｚとする。第１の位相差層１１の厚さをｔ１とする。 The in-plane retardation Re1 of the first retardation layer 11 is represented by the absolute value of (n1x−n1y)×t1. Let n1x and n1y be refractive indices in directions parallel to the surface of the first retardation layer 11 (for example, the XY plane in FIGS. 2 and 3) and perpendicular to each other. Let n1z be the refractive index in the direction perpendicular to the surface of the first retardation layer 11 . Let t1 be the thickness of the first retardation layer 11 .
　第２の位相差層１２の面内リタデーションＲｅ２は、（ｎ２ｘ－ｎ２ｙ）×ｔ２の絶対値で表される。第２の位相差層１２面（例えば図２および図３のＸ－Ｙ平面）に平行であって、互いに直行する方向の屈折率をｎ２ｘおよびｎ２ｙとする。第２の位相差層１２面に垂直な方向の屈折率をｎ２ｚとする。第２の位相差層１２の厚さをｔ２とする。 The in-plane retardation Re2 of the second retardation layer 12 is represented by the absolute value of (n2x−n2y)×t2. Let n2x and n2y be refractive indices in directions parallel to the surface of the second retardation layer 12 (for example, the XY plane in FIGS. 2 and 3) and perpendicular to each other. Let n2z be the refractive index in the direction perpendicular to the surface of the second retardation layer 12 . Let t2 be the thickness of the second retardation layer 12 .
　第３の位相差層１３の面内リタデーションＲｅ３は、（ｎ３ｘ－ｎ３ｙ）×ｔ３の絶対値で表される。第３の位相差層１３面（例えば図２および図３のＸ－Ｙ平面）に平行であって、互いに直行する方向の屈折率をｎ３ｘおよびｎ３ｙとする。第３の位相差層１３面に垂直な方向の屈折率をｎ３ｚとする。第３の位相差層１３の厚さをｔ３とする。 The in-plane retardation Re3 of the third retardation layer 13 is represented by the absolute value of (n3x−n3y)×t3. Let n3x and n3y be refractive indices in directions parallel to the surface of the third retardation layer 13 (for example, the XY plane in FIGS. 2 and 3) and perpendicular to each other. Let n3z be the refractive index in the direction perpendicular to the surface of the third retardation layer 13 . Let t3 be the thickness of the third retardation layer 13 .
　屈折率のｘ方向およびｙ方向は、ｎｘおよびｎｙが液晶の異常光屈折率ｎｅの方向もしくは常光屈折率ｎｏの方向に等しくなるように定められる。例えば水平配向でｎｘ＝ｎｅ、ｎｙ＝ｎｚ＝ｎｏとなる場合、面内リタデーションは（ｎｘ－ｎｙ）×ｔ＝（ｎｅ－ｎо）×ｔとなり、面内リタデーションとリタデーションは等しくなる。一方垂直配向でｎｘ＝ｎｙ＝ｎｏ、ｎｚ＝ｎｅとなる場合、面内リタデーションは（ｎｘ－ｎｙ）×ｔ＝０であるが、リタデーションは（ｎｅ－ｎо）×ｔでゼロではない値をもつ。 The x-direction and y-direction of the refractive index are determined so that nx and ny are equal to the direction of the extraordinary refractive index ne or the direction of the ordinary refractive index no of the liquid crystal. For example, when nx=ne and ny=nz=no in the horizontal orientation, the in-plane retardation is (nx-ny).times.t=(ne-no).times.t, and the in-plane retardation is equal to the retardation. On the other hand, when nx = ny = no and nz = ne in the vertical orientation, the in-plane retardation is (nx - ny) x t = 0, but the retardation is (ne - no) x t and has a non-zero value. .
　（（波長板１が２層構造を有する場合））
　波長板１は、第１の位相差層１１と、第２の位相差層１２と、を有する２層構造を有する。第１の位相差層１１および第２の位相差層１２のうち、面内リタデーション（Ｒｅ１、Ｒｅ２）が大きい層をＡ層とし、小さい層をＢ層とする。Ａ層の面内リタデーションをＲｅＡとし、Ｂ層の面内リタデーションをＲｅＢとする。例えば、Ｒｅ１＞Ｒｅ２の場合は、第１の位相差層１１がＡ層となり、ＲｅＡ＝Ｒｅ１となる。第２の位相差層１２がＢ層となり、ＲｅＢ＝Ｒｅ２となる。 ((When the wave plate 1 has a two-layer structure))
The wave plate 1 has a two-layer structure having a first retardation layer 11 and a second retardation layer 12 . Among the first retardation layer 11 and the second retardation layer 12, a layer having a large in-plane retardation (Re1, Re2) is called an A layer, and a layer having a small in-plane retardation (Re1, Re2) is called a B layer. Let ReA be the in-plane retardation of the A layer, and ReB be the in-plane retardation of the B layer. For example, when Re1>Re2, the first retardation layer 11 is the A layer, and ReA=Re1. The second retardation layer 12 becomes the B layer, and ReB=Re2.
　Ａ層の厚さ方向のリタデーションＲｔｈＡは、次式により表される。
ＲｔｈＡ＝（（ｎＡｘ＋ｎＡｙ）/２－ｎＡｚ）×ｔＡ
ｎＡｘは、Ａ層の波長５５０ｎｍにおけるＸ軸方向の屈折率を表す。ｎＡｙは、Ａ層の波長５５０ｎｍにおけるＹ軸方向の屈折率を表す。ｎＡｚは、Ａ層の波長５５０ｎｍにおけるＺ軸方向の屈折率を表す。ｔＡはＡ層の厚みを表す。 The thickness direction retardation RthA of the A layer is represented by the following equation.
RthA = ((nAx + nAy)/2-nAz) x tA
nAx represents the refractive index of the A layer in the X-axis direction at a wavelength of 550 nm. nAy represents the refractive index of the A layer in the Y-axis direction at a wavelength of 550 nm. nAz represents the refractive index of the A layer in the Z-axis direction at a wavelength of 550 nm. tA represents the thickness of the A layer.
　Ｂ層の厚さ方向のリタデーションＲｔｈＢは、次式により表される。
ＲｔｈＢ＝（（ｎＢｘ＋ｎＢｙ）/２－ｎＢｚ）×ｔＢ
ｎＢｘは、Ｂ層の波長５５０ｎｍにおけるＸ軸方向の屈折率を表す。ｎＢｙは、Ｂ層の波長５５０ｎｍにおけるＹ軸方向の屈折率を表す。ｎＢｚは、Ｂ層の波長５５０ｎｍにおけるＺ軸方向の屈折率を表す。ｔＢはＢ層の厚みを表す。 The thickness direction retardation RthB of the B layer is expressed by the following equation.
RthB=((nBx+nBy)/2−nBz)×tB
nBx represents the refractive index of the B layer in the X-axis direction at a wavelength of 550 nm. nBy represents the refractive index of the B layer in the Y-axis direction at a wavelength of 550 nm. nBz represents the refractive index of the B layer in the Z-axis direction at a wavelength of 550 nm. tB represents the thickness of the B layer.
　（（波長板１が３層構造を有する場合））
　波長板１は、第１の位相差層１１、第２の位相差層１２および第３の位相差層１３を有する。第１の位相差層１１、第２の位相差層１２および第３の位相差層において、面内リタデーション（Ｒｅ１～Ｒｅ３）が大きい層から小さい層の順にａ層、ｂ層およびｃ層とする。ａ層の面内リタデーションをＲｅａとし、ｂ層の面内リタデーションをＲｅｂとし、ｃ層の面内リタデーションをＲｅｃとする。 ((When the wave plate 1 has a three-layer structure))
Wave plate 1 has first retardation layer 11 , second retardation layer 12 and third retardation layer 13 . In the first retardation layer 11, the second retardation layer 12, and the third retardation layer, the in-plane retardation (Re1 to Re3) is a layer, b layer, and c layer in descending order. . Let Rea be the in-plane retardation of the a layer, Reb be the in-plane retardation of the b layer, and Rec be the in-plane retardation of the c layer.
　例えば、Ｒｅ１＞Ｒｅ３＞Ｒｅ２の場合は、第１の位相差層１１がａ層となり、Ｒｅａ＝Ｒｅ１となる。第２の位相差層１２がｃ層となり、Ｒｅｃ＝Ｒｅ２となる。第３の位相差層１３がｂ層となり、Ｒｅｂ＝Ｒｅ３となる。また、Ｒｅ１＝Ｒｅ２（またはＲｅ１＝Ｒｅ３）である場合には、直線偏光を入射する側に近い層をａ層、遠い方をｂ層とする。 For example, when Re1>Re3>Re2, the first retardation layer 11 is the a layer, and Rea=Re1. The second retardation layer 12 becomes the c layer, and Rec=Re2. The third retardation layer 13 becomes the b layer, and Reb=Re3. When Re1=Re2 (or Re1=Re3), the layer closer to the linearly polarized light incident side is the a layer, and the farther side is the b layer.
　ａ層の厚さ方向のリタデーションＲｔｈａは、次式により表される。
Ｒｔｈａ＝（（ｎａｘ＋ｎａｙ）／２－ｎａｚ）×ｔａ
ｎａｘは、ａ層の波長５５０ｎｍにおけるＸ軸方向の屈折率を表す。ｎａｙは、ａ層の波長５５０ｎｍにおけるＹ軸方向の屈折率を表す。ｎａｚは、ａ層の波長５５０ｎｍにおけるＺ軸方向の屈折率を表す。ｔａはａ層の厚みを表す。 The retardation Rtha in the thickness direction of the a layer is expressed by the following equation.
Rtha=((nax+nay)/2−naz)×ta
nax represents the refractive index of the a layer in the X-axis direction at a wavelength of 550 nm. nay represents the refractive index of the a layer in the Y-axis direction at a wavelength of 550 nm. naz represents the refractive index of the a layer in the Z-axis direction at a wavelength of 550 nm. ta represents the thickness of the a layer.
　ｂ層の厚さ方向のリタデーションＲｔｈｂは、次式により表される。
Ｒｔｈｂ＝（（ｎｂｘ＋ｎｂｙ）／２－ｎｂｚ）×ｔｂ
ｎｂｘは、ｂ層の波長５５０ｎｍにおけるＸ軸方向の屈折率を表す。ｎｂｙは、ｂ層の波長５５０ｎｍにおけるＹ軸方向の屈折率を表す。ｎｂｚは、ｂ層の波長５５０ｎｍにおけるＺ軸方向の屈折率を表す。ｔｂはｂ層の厚みを表す。 The retardation Rthb in the thickness direction of the b layer is expressed by the following equation.
Rthb=((nbx+nby)/2-nbz)×tb
nbx represents the refractive index of the b layer in the X-axis direction at a wavelength of 550 nm. nby represents the refractive index of the b layer in the Y-axis direction at a wavelength of 550 nm. nbz represents the refractive index of the b layer in the Z-axis direction at a wavelength of 550 nm. tb represents the thickness of the b layer.
　ｃ層の厚さ方向のリタデーションＲｔｈｃは、次式により表される。
Ｒｔｈｃ＝（（ｎｃｘ＋ｎｃｙ）／２－ｎｃｚ）×ｔｃ
ｎｃｘは、ｃ層の波長５５０ｎｍにおけるＸ軸方向の屈折率を表す。ｎｃｙは、ｃ層の波長５５０ｎｍにおけるＹ軸方向の屈折率を表す。ｎｃｚは、ｃ層の波長５５０ｎｍにおけるＺ軸方向の屈折率を表す。ｔｃはｃ層の厚みを表す。 The retardation Rthc in the thickness direction of the c layer is expressed by the following equation.
Rthc=((ncx+ncy)/2−ncz)×tc
ncx represents the refractive index of the c layer in the X-axis direction at a wavelength of 550 nm. ncy represents the refractive index of the c layer in the Y-axis direction at a wavelength of 550 nm. ncz represents the refractive index of the c layer in the Z-axis direction at a wavelength of 550 nm. tc represents the thickness of the c layer.
　面内リタデーションＲｅＡおよびＲｅＢは、ＲｅＡ＜ＲｅＢ－５０（ｎｍ）、ＲｅＡ＞ＲｅＢ＋５０（ｎｍ）、かつＲｅＢ＞５０（ｎｍ）が好ましい。ＲｅＢは７０ｎｍ以上が好ましく、９０ｎｍ以上がより好ましい。面内リタデーションＲｅａ、面内リタデーションＲｅｂは、Ｒｅａ＜Ｒｅｂ－５０（ｎｍ）、Ｒｅａ＞Ｒｅｂ＋５０（ｎｍ）、かつＲｅｂ＞５０ｎｍが好ましい。Ｒｅｂは７０ｎｍ以上が好ましく、９０ｎｍ以上がより好ましい。 The in-plane retardations ReA and ReB are preferably ReA<ReB-50 (nm), ReA>ReB+50 (nm), and ReB>50 (nm). ReB is preferably 70 nm or more, more preferably 90 nm or more. In-plane retardation Rea and in-plane retardation Reb are preferably Rea<Reb−50 (nm), Rea>Reb+50 (nm), and Reb>50 nm. Reb is preferably 70 nm or more, more preferably 90 nm or more.
　換言すると、波長板１は、第１の位相差層１１および第２の位相差層１２を備え、第１の位相差層１１側から直線偏光を入射して第２の位相差層１２側から円偏光を出射し、又は、第２の位相差層１２側から円偏光を入射して第１の位相差層１１側から直線偏光を出射する。第１の位相差層１１は、第１の液晶層１１０を含み、第２の位相差層１２は、第２の液晶層１２０を含む。第１の位相差層１１のリタデーションＲ１および第２の位相差層１２のリタデーションＲ２は、それぞれが２０ｎｍ以上であり、Ｒ１およびＲ２を比較したとき、リタデーションが大きい方の位相差層の厚さ方向のリタデーションＲｔｈＡは正である。 In other words, the wave plate 1 includes the first retardation layer 11 and the second retardation layer 12, and the linearly polarized light is incident from the first retardation layer 11 side and from the second retardation layer 12 side Circularly polarized light is emitted, or circularly polarized light is incident from the second retardation layer 12 side and linearly polarized light is emitted from the first retardation layer 11 side. The first retardation layer 11 includes a first liquid crystal layer 110 and the second retardation layer 12 includes a second liquid crystal layer 120 . The retardation R1 of the first retardation layer 11 and the retardation R2 of the second retardation layer 12 are each 20 nm or more, and when comparing R1 and R2, the retardation is larger in the thickness direction of the retardation layer has a positive retardation RthA.
　あるいは波長板１は特に、第１の位相差層１１、第２の位相差層１２、および第３の位相差層１３をこの順に備え、第１の位相差層１１側から直線偏光を入射して第３の位相差層１３側から円偏光を出射し、又は、第３の位相差層１３側から円偏光を入射して第１の位相差層１１側から直線偏光を出射する。第１の位相差層１１は、第１の液晶層１１０を含み、第２の位相差層１２は、第２の液晶層１２０を含み、第３の位相差層１３は、第３の液晶層１３０を含む。第１の位相差層１１のリタデーションＲ１、第２の位相差層１２のリタデーションＲ２、および第３の位相差層１３のリタデーションＲ３は、それぞれが２０ｎｍ以上であり、Ｒ１、Ｒ２およびＲ３を比較したとき、リタデーションが一番大きい位相差層の厚さ方向のリタデーションＲｔｈａは正である。第１の位相差層１１のリタデーションＲ１、第２の位相差層１２のリタデーションＲ２、および第３の位相差層１３のリタデーションＲ３は、好ましくは３０ｎｍ以上、より好ましくは４０ｎｍ以上である。好ましくは、ＲｔｈＢは負であるか、あるいはＲｔｈｂは正であってＲｔｈｃは負である。 Alternatively, the wave plate 1 particularly includes a first retardation layer 11, a second retardation layer 12, and a third retardation layer 13 in this order, and linearly polarized light is incident from the first retardation layer 11 side. Circularly polarized light is emitted from the third retardation layer 13 side, or circularly polarized light is incident from the third retardation layer 13 side and linearly polarized light is emitted from the first retardation layer 11 side. The first retardation layer 11 includes a first liquid crystal layer 110, the second retardation layer 12 includes a second liquid crystal layer 120, and the third retardation layer 13 includes a third liquid crystal layer. 130 included. The retardation R1 of the first retardation layer 11, the retardation R2 of the second retardation layer 12, and the retardation R3 of the third retardation layer 13 are each 20 nm or more, and R1, R2 and R3 were compared. At this time, the retardation Rtha in the thickness direction of the retardation layer having the largest retardation is positive. The retardation R1 of the first retardation layer 11, the retardation R2 of the second retardation layer 12, and the retardation R3 of the third retardation layer 13 are preferably 30 nm or more, more preferably 40 nm or more. Preferably, RthB is negative or Rthb is positive and Rthc is negative.
　ここで、図１２は、第１の位相差層１１における第２の位相差層１２側の出射側遅相軸１１６ｅと、第２の位相差層１２における第１の位相差層１１側の入射側遅相軸１１６ｓとのなす遅相軸方位角Δφｃを例示する図である。なお、図１２では、出射側遅相軸１１６ｅおよび入射側遅相軸１１６ｓがＸ－Ｙ平面に平行である例を示すが、出射側遅相軸１１６ｅ又は入射側遅相軸１１６ｓの少なくとも一方はＸ－Ｙ平面に対して傾いていてもよい。つまり、遅相軸方位角Δφｃは３次元空間内において出射側遅相軸１１６ｅと入射側遅相軸１１６ｓとがなす角である。また、液晶分子１１５がねじれて配向する厚さ方向は、図１２ではＺ方向に対応する。 Here, FIG. 12 shows the output-side slow axis 116e of the first retardation layer 11 on the side of the second retardation layer 12, and the incident side of the second retardation layer 12 on the side of the first retardation layer 11. FIG. 11 is a diagram illustrating a slow axis azimuth angle Δφc formed with the side slow axis 116s; Although FIG. 12 shows an example in which the output-side slow axis 116e and the incident-side slow axis 116s are parallel to the XY plane, at least one of the output-side slow axis 116e and the incident-side slow axis 116s It may be tilted with respect to the XY plane. That is, the slow axis azimuth angle Δφc is the angle formed by the output-side slow axis 116e and the incident-side slow axis 116s in the three-dimensional space. The thickness direction in which the liquid crystal molecules 115 are twisted and aligned corresponds to the Z direction in FIG.
　第１の位相差層１１における第２の位相差層１２側の出射側遅相軸１１６ｅと、第２の位相差層１２における第１の位相差層１１側の入射側遅相軸１１６ｓと、がなす遅相軸方位角Δφｃの制御方法等には、例えば以下に示す方法を適用できる。第１の位相差層１１および第２の位相差層１２は、それぞれの軸角度が調整された後、適宜又は一括で貼り合わされる。第３の位相差層１３が設けられる場合には、第１の位相差層１１、第２の位相差層１２および第３の位相差層１３は、それぞれの軸角度が調整された後、適宜又は一括で貼り合わされる。ここで、軸角度とは、基準に対して各層の遅相軸がなす角度をいう。 An output-side slow axis 116e on the side of the second retardation layer 12 in the first retardation layer 11, and an incident-side slow axis 116s on the side of the first retardation layer 11 in the second retardation layer 12, For example, the following method can be applied to control the slow axis azimuth angle Δφc. After the respective axis angles are adjusted, the first retardation layer 11 and the second retardation layer 12 are appropriately or collectively bonded together. When the third retardation layer 13 is provided, the first retardation layer 11, the second retardation layer 12, and the third retardation layer 13 are appropriately adjusted after their respective axis angles are adjusted. Alternatively, they are stuck together. Here, the axis angle means the angle formed by the slow axis of each layer with respect to the reference.
　各層の軸角度は、例えば測定サンプル（波長板）の外形を基準に決定できる。貼り合わせ角度は、同じく測定サンプルの外形を基準に制御できる。なお、各層の軸角度の基準は必ずしも外形でなくてよく、例えば測定サンプルのアライメントマーク等を基準にすることもできる。 The axis angle of each layer can be determined, for example, based on the external shape of the measurement sample (wave plate). The bonding angle can also be controlled based on the outer shape of the measurement sample. Note that the reference of the axis angle of each layer does not necessarily have to be the outer shape, and for example, the alignment mark of the measurement sample can be used as the reference.
　軸角度は、例えばＡｘｏｍｅｔｒｉｃｓ社のＡｘｏｓｃａｎ装置、又は大塚電子社のＲＥ―１００等の装置と、それぞれに付属の解析ソフトを用いて測定してもよい。ねじれ角も同様に上記装置と解析ソフトを用いて測定できる。これらから求めた軸角度とねじれ角を用いて、出射側遅相軸１１６ｅと入射側遅相軸１１６ｓとがなす遅相軸方位角Δφｃを測定できる。 The axial angle may be measured using, for example, an Axoscan device from Axometrics, or a device such as RE-100 from Otsuka Electronics, and analysis software attached thereto. The torsion angle can also be similarly measured using the above device and analysis software. Using the axial angle and the twist angle obtained from these, the slow axis azimuth angle Δφc between the output-side slow axis 116e and the incident-side slow axis 116s can be measured.
　図１３は、第１の位相差層１１の波長５５０ｎｍにおける面内リタデーションＲｅ１を例示する図である。図１３は、第１の位相差層１１が入射する電場成分Ｐ１Ｘおよび電場成分Ｐ１Ｙと、第１の位相差層１１が出射する電場成分Ｐ１Ｘ'および電場成分Ｐ１Ｙ'と、を示している。第１の位相差層１１における電場成分Ｐ１Ｙ'が電場成分Ｐ１Ｘ'に対して遅れる距離は、面内リタデーションＲｅ１に対応する。第２の位相差層１２における電場成分Ｐ１Ｙ'が電場成分Ｐ１Ｘ'に対して遅れる距離は、面内リタデーションＲｅ２に対応する。 FIG. 13 is a diagram illustrating the in-plane retardation Re1 of the first retardation layer 11 at a wavelength of 550 nm. FIG. 13 shows an electric field component P1X and an electric field component P1Y incident on the first retardation layer 11, and an electric field component P1X' and an electric field component P1Y' emitted from the first retardation layer 11. FIG. The distance by which the electric field component P1Y' in the first retardation layer 11 lags behind the electric field component P1X' corresponds to the in-plane retardation Re1. The distance by which the electric field component P1Y' in the second retardation layer 12 lags behind the electric field component P1X' corresponds to the in-plane retardation Re2.
　プリズムカプラは、基板上に形成された薄膜の屈折率を測定する装置である。エリプソメータは、物質表面に入射した偏光の物質表面による反射光の偏光状態を測定し、物質の屈折率あるいは物質表面に形成された薄膜の厚さおよび屈折率を測定する装置である。 A prism coupler is a device that measures the refractive index of a thin film formed on a substrate. An ellipsometer is a device that measures the polarization state of polarized light incident on a material surface and reflected by the material surface, and measures the refractive index of the material or the thickness and refractive index of a thin film formed on the material surface.
　〈実施例、比較例〉
　以下、実施例、比較例について説明するが、本発明は、これらの例に何ら限定されない。 <Examples, Comparative Examples>
Examples and comparative examples will be described below, but the present invention is not limited to these examples.
　（評価方法）
　面内リタデーションＲｅおよび厚み方向のリタデーションＲｔｈは、例えばＡｘｏｍｅｔｒｉｃｓ社のＡｘｏｓｃａｎ装置、又は大塚電子社のＲＥ－１００、王子計測株式会社のＫＯＢＲＡ等とそれぞれの装置に付属の解析ソフトを用いて測定できる。 (Evaluation method)
The in-plane retardation Re and the retardation Rth in the thickness direction can be measured using, for example, an Axoscan device manufactured by Axometrics, RE-100 manufactured by Otsuka Electronics Co., Ltd., KOBRA manufactured by Oji Keisoku Co., Ltd., and analysis software attached to each device.
　リタデーションＲは、プリズムカプラやエリプソメータにより測定した異常光屈折率ｎｅ、常光屈折率ｎｏおよび膜厚ｔを用い、「（ｎｅ－ｎｏ）×ｔ」を算出すること等によっても測定できる。 The retardation R can also be measured by calculating "(ne−no)×t" using the extraordinary refractive index ne, the ordinary refractive index no, and the film thickness t measured by a prism coupler or an ellipsometer.
　膜厚ｔはエリプソメータによる解析のほかに、例えばミツトヨ社ＡＢＳデジマチックインジケータＩＤ－Ｃ１１２ＣＸを用いたり、サンプルを割断して断面ＳＥＭ観察して測長したりすること等により測定できる。垂直配向のリタデーションを測定する場合には、対象の液晶分子を基板上に水平配向させた試験サンプルを前記プリズムカプラやエリプソメータ等により測定することによって異常光屈折率ｎｅおよび常光屈折率ｎｏを測定できる。 In addition to analysis by an ellipsometer, the film thickness t can be measured by, for example, using Mitutoyo's ABS Digimatic Indicator ID-C112CX, cutting a sample, observing the cross section with an SEM, and measuring the length. In the case of measuring the retardation of vertical alignment, the extraordinary refractive index ne and the ordinary refractive index no can be measured by measuring a test sample in which the target liquid crystal molecules are horizontally aligned on the substrate with the prism coupler, ellipsometer, or the like. .
　実施例、比較例では、波長板に入射する直線偏光の可視光を波長板により変換した円偏光の楕円率をシミュレーションにより算出して評価した。入射角および入射方位角をそれぞれ変化させ、複数の入射角および入射方位角ごとに楕円率を算出した。 In the examples and comparative examples, the ellipticity of the circularly polarized light obtained by converting the linearly polarized visible light incident on the wave plate by the wave plate was calculated and evaluated by simulation. The incident angle and incident azimuth angle were varied, and the ellipticity was calculated for each of a plurality of incident angles and incident azimuth angles.
　（入射角および入射方位角）
　図１４は、波長板に入射する光の入射角および入射方位角を説明する図である。図１４において、Ｘ－Ｙ平面は、波長板１の境界面１０と平行な平面であり、Ｚ軸は境界面１０の法線である。入射角θは、境界面１０に入射する直線偏光Ｐ１の入射方向と、Ｚ軸と、がなす角である。入射方位角ηは、境界面１０内において、直線偏光Ｐ１の方位と、基準となる方位であるＸ軸と、がなす角である。遅相軸方位角φｃは、第１の位相差層１１、第２の位相差層１２および第３の位相差層１３の各層における遅相軸１１６がＸ軸に対してなす角である。 (incident angle and incident azimuth angle)
FIG. 14 is a diagram for explaining the incident angle and incident azimuth angle of light incident on the wave plate. In FIG. 14, the XY plane is a plane parallel to the interface 10 of the wave plate 1, and the Z-axis is the normal to the interface 10. In FIG. The incident angle θ is the angle formed by the incident direction of the linearly polarized light P1 incident on the boundary surface 10 and the Z axis. The incident azimuth angle η is the angle between the azimuth of the linearly polarized light P1 and the X-axis, which is the reference azimuth, within the boundary surface 10 . The slow axis azimuth angle φc is the angle formed by the slow axis 116 in each of the first retardation layer 11, the second retardation layer 12, and the third retardation layer 13 with respect to the X axis.
　（楕円率）
　図１５は、偏光の楕円率を説明する図である。楕円Ｅは、Ｚ軸に沿って進行する光の、進行方向から視た電場の軌跡を表している。楕円Ｅの長軸の長さをａとし、短軸の長さをｂとすると、楕円率εはｂ／ａとなる。楕円率εが１のとき円偏光となり、楕円率εが０又は無限大のとき直線偏光となる。本実施形態では、楕円率εが１に近いほど楕円率が高く、波長板１の性能が高いことを意味する。 (ellipticity)
FIG. 15 is a diagram for explaining the ellipticity of polarized light. An ellipse E represents the trajectory of the electric field of the light traveling along the Z axis, viewed from the traveling direction. If the length of the major axis of the ellipse E is a and the length of the minor axis is b, the ellipticity ε is b/a. When the ellipticity ε is 1, the light is circularly polarized light, and when the ellipticity ε is 0 or infinite, the light is linearly polarized light. In this embodiment, the closer the ellipticity ε is to 1, the higher the ellipticity and the higher the performance of the wave plate 1 is.
　（シミュレーション方法）
　第１の位相差層１１、第２の位相差層１２および第３の位相差層１３の各層の構成は、後述する表１に示すようにモデリングした。シミュレーションにおいて使用する異常光屈折率ｎｅおよび常光屈折率ｎｏには、第１の位相差層１１、第２の位相差層１２および第３の位相差層１３の各層において使用する材料を石英基板に塗布し、これをプリズムカプラにより測定した結果を用いた。 (Simulation method)
The structure of each layer of the first retardation layer 11, the second retardation layer 12 and the third retardation layer 13 was modeled as shown in Table 1 below. For the extraordinary refractive index ne and the ordinary refractive index no used in the simulation, the material used in each of the first retardation layer 11, the second retardation layer 12, and the third retardation layer 13 is applied to the quartz substrate. The results obtained by coating and measuring this with a prism coupler were used.
　シミュレーションでは、拡張ジョーンズ行列法を用いて、第１の位相差層１１、第２の位相差層１２および第３の位相差層１３の各層を透過する偏光のストークスパラメータ（Ｓ０，Ｓ１，Ｓ２，Ｓ３）を算出した。このストークスパラメータ（Ｓ０，Ｓ１，Ｓ２，Ｓ３）に基づき、以下の式により楕円率εを算出した。 In the simulation, Stokes parameters (S0, S1, S2, S3) was calculated. Based on these Stokes parameters (S0, S1, S2, S3), the ellipticity ε was calculated by the following formula.
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000001
　（楕円率面積）
　複数の入射角および入射方位角において得られる楕円率εと、可視光の波長範囲内において波長λごとに得られる楕円率εと、を用いて評価を行うために、楕円率面積を評価指標として用いた。 (ellipticity area)
In order to evaluate using the ellipticity ε obtained at multiple incident angles and incident azimuth angles and the ellipticity ε obtained for each wavelength λ within the wavelength range of visible light, the ellipticity area is used as an evaluation index. Using.
　図１６および図１７Ａは楕円率面積を説明する図である。図１６は、波長λに伴う楕円率εの変化を例示する図である。図１７Ａは、図１６におけるΔλの範囲内での楕円率εを示す矩形領域１５１を取り出して示した図である。 16 and 17A are diagrams for explaining the ellipticity area. FIG. 16 is a diagram illustrating changes in ellipticity ε with wavelength λ. FIG. 17A is a diagram extracting and showing a rectangular region 151 showing the ellipticity ε within the range of Δλ in FIG.
　図１７Ａに示すように、波長幅Δλの波長範囲内において、最短の波長λ０における楕円率ε（λ０）と、最長の波長λ１における楕円率ε（λ１）の平均値である楕円率ε（ａｖｇ．）を算出し、波長幅Δλとε（ａｖｇ．）の積により矩形領域１５１の面積を算出した。４００ｎｍから７００ｎｍの範囲をΔλ＝１０（ｎｍ）により３０分割し、３０個の矩形領域１５１の面積を加算した加算値を求めた。複数の入射角および入射方位角のそれぞれにおいて求めた矩形領域１５１の面積加算値の総和を楕円率面積とした。 As shown in FIG. 17A, within the wavelength range of the wavelength width Δλ, the ellipticity ε (λ0) at the shortest wavelength λ0 and the ellipticity ε (λ1) at the longest wavelength λ1, which is the average value of the ellipticity ε (avg ) was calculated, and the area of the rectangular region 151 was calculated from the product of the wavelength width Δλ and ε (avg.). A range from 400 nm to 700 nm was divided into 30 parts by Δλ=10 (nm), and an added value was obtained by adding the areas of 30 rectangular regions 151 . The total sum of the area addition values of the rectangular regions 151 obtained at each of a plurality of incident angles and incident azimuth angles was defined as the ellipticity area.
　（波長板の構成、評価結果）
　表１に実施例、比較例の構成および評価結果を示す。例１から例６は実施例、例７および例８は比較例である。 (Structure of wave plate, evaluation results)
Table 1 shows the configurations and evaluation results of Examples and Comparative Examples. Examples 1 to 6 are examples, and examples 7 and 8 are comparative examples.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表１は、実施例、比較例ごとにおいて、第１の位相差層１１、第２の位相差層１２および第３の位相差層１３の各構成を示している。例３および例７に係る波長板１は、第１の位相差層１１と、第２の位相差層１２と、を含むものとした。例３および例７以外の例に係る波長板１は、第１の位相差層１１と、第２の位相差層１２と、第３の位相差層１３と、を含むものとした。 Table 1 shows each configuration of the first retardation layer 11, the second retardation layer 12, and the third retardation layer 13 for each example and comparative example. Wave plates 1 according to Examples 3 and 7 included a first retardation layer 11 and a second retardation layer 12 . Wave plates 1 according to examples other than Examples 3 and 7 include a first retardation layer 11 , a second retardation layer 12 , and a third retardation layer 13 .
　例１から例８に係る波長板１は、第１の位相差層１１側から直線偏光Ｐ１を入射し、第１の位相差層１１とは反対側から円偏光Ｐ２を出射するか、或いは第１の位相差層１１とは反対側から円偏光Ｐ２を入射し、第１の位相差層１１側から直線偏光Ｐ１を出射するものである。円偏光Ｐ２を入射する場合、例１、例２、例４、例５、例６および例８では、第３の位相差層１３から円偏光Ｐ２を入射し、例３および例７では、第２の位相差層１２から円偏光Ｐ２を入射する。 The wave plates 1 according to Examples 1 to 8 enter the linearly polarized light P1 from the side of the first retardation layer 11 and emit the circularly polarized light P2 from the side opposite to the first retardation layer 11, or Circularly polarized light P2 is incident from the side opposite to the first retardation layer 11, and linearly polarized light P1 is emitted from the first retardation layer 11 side. When the circularly polarized light P2 is incident, in Examples 1, 2, 4, 5, 6 and 8, the circularly polarized light P2 is incident from the third retardation layer 13, and in Examples 3 and 7, the Circularly polarized light P2 is incident from the second retardation layer 12 .
　「入射偏光」は、第１の位相差層１１に対して入射又は出射する直線偏光Ｐ１の偏光軸方位を示す。「Ｘ」はＸ軸に、「Ｙ」はＹ軸に、それぞれ偏光軸方位が沿っていることを表す。但し、直線偏光Ｐ１の偏光軸方位角φ０は、Ｘ軸又はＹ軸に沿うものに限定されない。直線偏光Ｐ１が、第１の位相差層１１に対し、所定の偏光軸方位角φ０において入射又は出射できれば、直線偏光Ｐ１の偏光軸方位角φ０は、波長板１の使用用途に応じて適宜設定可能である。例えば波長板１の使用用途に応じて、より高い楕円率の偏光が得られるように、直線偏光Ｐ１の偏光軸方位角φ０を設定できる。 "Incident polarized light" indicates the polarization axis direction of the linearly polarized light P1 incident on or emitted from the first retardation layer 11 . "X" and "Y" indicate that the polarization axis is along the X axis and the Y axis, respectively. However, the polarization axis azimuth φ0 of the linearly polarized light P1 is not limited to along the X-axis or the Y-axis. If the linearly polarized light P1 can be incident on or emitted from the first retardation layer 11 at a predetermined polarization axis azimuth angle φ0, the polarization axis azimuth angle φ0 of the linearly polarized light P1 is appropriately set according to the intended use of the wave plate 1. It is possible. For example, the polarization axis azimuth φ0 of the linearly polarized light P1 can be set so as to obtain polarized light with a higher ellipticity depending on the intended use of the wave plate 1 .
　各位相差層における「液晶層」は、液晶層の種類を示している。「正分散ねじれ」は正分散性を有してねじれ配向している液晶層、「逆分散ねじれ」は逆分散性を有してねじれ配向している液晶層を示す。「逆分散ａ－ｐｌａｔｅ」は逆分散性を有して水平配向している液晶層、「垂直ｃ－ｐｌａｔｅ」は垂直配向している液晶層、「正分散ａ－ｐｌａｔｅ」は正分散性を有して水平配向している液晶層を示す。 "Liquid crystal layer" in each retardation layer indicates the type of liquid crystal layer. "Positive dispersion twist" indicates a twisted liquid crystal layer having positive dispersion, and "reverse dispersion twist" indicates a twisted liquid crystal layer having reverse dispersion. "Reverse dispersion a-plate" is a horizontally aligned liquid crystal layer having reverse dispersion, "vertical c-plate" is a vertically aligned liquid crystal layer, and "positive dispersion a-plate" is positive dispersion. 1 shows a liquid crystal layer with horizontal alignment.
　「φｃ_ｓ１（°）」は、第１の位相差層１１における光入射側の遅相軸方位角、「φｃ_ｓ２（°）」は、第２の位相差層１２における光入射側の遅相軸方位角、「φｃ_ｓ３（°）」は第３の位相差層１３における光入射側の遅相軸方位角をそれぞれ示す。なお、以下の説明では、位相差層を特に区別せずに光入射側の遅相軸方位角を示す場合にはφｃ_ｓと総称表記する。 “φc_s1 (°)” is the slow axis azimuth on the light incident side in the first retardation layer 11, and “φc_s2 (°)” is the slow axis azimuth on the light incident side in the second retardation layer 12. The angle “φc_s3 (°)” indicates the slow axis azimuth angle of the third retardation layer 13 on the light incident side. In the following description, the azimuth angle of the slow axis on the light incident side is collectively referred to as φc_s without distinguishing between the retardation layers.
　「φｃ_ｅ１（°）」は、第１の位相差層１１における光出射側の遅相軸方位角、「φｃ_ｅ２（°）」は、第２の位相差層１２における光出射側の遅相軸方位角、「φｃ_ｅ３（°）」は、第３の位相差層１３における光出射側の遅相軸方位角を示す。なお、以下の説明では、位相差層を特に区別せずに光出射側の遅相軸方位角を示す場合にはφｃ_ｅと総称表記する。 “φc_e1 (°)” is the slow axis azimuth angle on the light output side of the first retardation layer 11, and “φc_e2 (°)” is the slow axis azimuth on the light output side of the second retardation layer 12. The angle “φc_e3(°)” indicates the slow axis azimuth angle of the third retardation layer 13 on the light exit side. In the following description, the azimuth angle of the slow axis on the light exit side is collectively referred to as φc_e without distinguishing between the retardation layers.
　遅相軸方位角φｃ_ｓおよび遅相軸方位角φｃ_ｅは、それぞれ基準に対する角度である。本実施形態ではＸ軸を基準としているが、これに限定されるものではなく、波長板１の使用用途等に応じて適宜設定可能である。なお、垂直配向している液晶層では、境界面１０に対して直交する方向に液晶分子が配向し、遅相軸はＸ軸に対して直交するため、表１では遅相軸方位角φｃ_ｓおよび遅相軸方位角φｃ_ｅを「９０°」と表記した。また、表１における垂直配向以外の液晶層では、遅相軸方位角φｃ_ｓおよび遅相軸方位角φｃ_ｅは、境界面１０と略平行な平面内におけるＸ軸に対する角度を表している。反時計回りが正、時計回りが負である。 The slow axis azimuth angle φc_s and the slow axis azimuth angle φc_e are angles relative to the reference. In this embodiment, the X-axis is used as a reference, but it is not limited to this, and can be set as appropriate according to the intended use of the wave plate 1 or the like. In the vertically aligned liquid crystal layer, the liquid crystal molecules are oriented in a direction perpendicular to the interface 10, and the slow axis is perpendicular to the X axis. The slow axis azimuth angle φc_e is expressed as “90°”. In addition, in the liquid crystal layers other than the vertical alignment in Table 1, the slow axis azimuth angle φc_s and the slow axis azimuth angle φc_e represent angles with respect to the X-axis in a plane substantially parallel to the interface 10 . Counterclockwise is positive, clockwise is negative.
　「ねじれ角」は、ねじれ配向している液晶層において、厚さ方向にねじれて配向している複数の液晶分子の遅相軸同士の、境界面１０内における最大角度差を表す。水平配向および垂直配向している液晶層では、複数の液晶分子は略一定の方向に配向するため、「ねじれ角」は「０」である。なお、ねじれ角は例えばＡｘｏｍｅｔｒｉｃｓ社のＡｘｏｓｃａｎ装置、または大塚電子社のＲＥ－１００等と、それぞれの装置に付属の解析ソフトと、を用いて測定できる。 The "twist angle" represents the maximum angular difference within the boundary plane 10 between the slow axes of a plurality of liquid crystal molecules twisted and aligned in the thickness direction in the twisted liquid crystal layer. In the horizontally aligned and vertically aligned liquid crystal layers, the "twist angle" is "0" because the plurality of liquid crystal molecules are aligned in a substantially constant direction. The twist angle can be measured using, for example, an Axoscan device from Axometrics, RE-100 from Otsuka Electronics, or the like, and analysis software attached to each device.
　「膜厚（μｍ）」は液晶層の膜厚、「Ｒｅ１（ｎｍ）」は第１の位相差層１１における面内リタデーション、「Ｒｅ２（ｎｍ）」は第２の位相差層１２における面内リタデーション、「Ｒｅ３（ｎｍ）」は第３の位相差層１３における面内リタデーションを示す。面内リタデーションは、波長λが５５０ｎｍに対応するものである。液晶層の膜厚は例えばミツトヨ社ＡＢＳデジマチックインジケータＩＤ－Ｃ１１２ＣＸ、サンプルを割断して断面ＳＥＭ観察して測長すること等により測定できる。 “Film thickness (μm)” is the film thickness of the liquid crystal layer, “Re1 (nm)” is the in-plane retardation in the first retardation layer 11, and “Re2 (nm)” is the in-plane retardation in the second retardation layer 12. Retardation “Re3 (nm)” indicates in-plane retardation in the third retardation layer 13 . The in-plane retardation corresponds to a wavelength λ of 550 nm. The film thickness of the liquid crystal layer can be measured by, for example, Mitutoyo's ABS Digimatic Indicator ID-C112CX, cutting a sample, observing the cross section with an SEM, and measuring the length.
　面内リタデーションＲｅ１、Ｒｅ２およびＲｅ３は、例えばＡｘｏｍｅｔｒｉｃｓ社のＡｘｏｓｃａｎ装置、または大塚電子社のＲＥ－１００等と、それぞれの装置に付属の解析ソフトと、を用いて測定できる。あるいは、プリズムカプラやエリプソメータ等により求めた異常光屈折率ｎｅ、常光屈折率ｎｏおよび膜厚ｔから「（ｎｅ－ｎｏ）×ｔ」を算出すること等により測定できる。 The in-plane retardations Re1, Re2, and Re3 can be measured using, for example, an Axoscan device from Axometrics, or RE-100 from Otsuka Electronics, and analysis software attached to each device. Alternatively, it can be measured by calculating "(ne−no)×t" from the extraordinary refractive index ne, the ordinary refractive index no, and the film thickness t obtained by a prism coupler, ellipsometer, or the like.
　「Ｒ１（ｎｍ）」は第１の位相差層１１におけるリタデーション、「Ｒ２（ｎｍ）」は第２の位相差層１２におけるリタデーション、「Ｒ３（ｎｍ）」は第３の位相差層１３におけるリタデーションである。 "R1 (nm)" is the retardation in the first retardation layer 11, "R2 (nm)" is the retardation in the second retardation layer 12, and "R3 (nm)" is the retardation in the third retardation layer 13. is.
　リタデーションＲ１、Ｒ２およびＲ３は、例えばＡｘｏｍｅｔｒｉｃｓ社のＡｘｏｓｃａｎ装置、又は大塚電子社のＲＥ－１００等と、それぞれの装置に付属の解析ソフトと、を用いて測定できる。また、Ｒ１、Ｒ２およびＲ３は、プリズムカプラやエリプソメータ等により求めた異常光屈折率ｎｅ、常光屈折率ｎｏおよび膜厚ｔから「（ｎｅ－ｎｏ）×ｔ」を算出すること等により測定できる。垂直配向のリタデーションを測定する場合は、対象の液晶分子を基板上に水平配向させた試験サンプルをプリズムカプラやエリプソメータ等により測定することによって異常光屈折率ｎｅおよび常光屈折率ｎｏを測定できる。 The retardations R1, R2, and R3 can be measured using, for example, an Axoscan device from Axometrics, RE-100 from Otsuka Electronics, or the like, and analysis software attached to each device. Also, R1, R2 and R3 can be measured by calculating "(ne−no)×t" from the extraordinary refractive index ne, the ordinary refractive index no and the film thickness t obtained by a prism coupler or an ellipsometer. When measuring the retardation of vertical alignment, the extraordinary refractive index ne and the ordinary refractive index no can be measured by measuring a test sample in which target liquid crystal molecules are horizontally aligned on a substrate with a prism coupler, an ellipsometer, or the like.
　Ｒｔｈ（ｎｍ）は位相差層の厚さ方向におけるリタデーションである。リタデーションは、波長λが５５０ｎｍに対応するものである。波長板１が２層構造である場合には、ＲｔｈＡ（ｎｍ）は、Ａ層の厚さ方向のリタデーションである。ＲｔｈＢ（ｎｍ）は、Ｂ層の厚さ方向のリタデーションである。面内リタデーションＲｅ１およびＲｅ２のうち、面内リタデーションが大きい層はＡ層、小さい層はＢ層に該当する。 Rth (nm) is the retardation in the thickness direction of the retardation layer. The retardation corresponds to a wavelength λ of 550 nm. When the wave plate 1 has a two-layer structure, RthA (nm) is the retardation of the A layer in the thickness direction. RthB (nm) is the retardation in the thickness direction of the B layer. Among the in-plane retardations Re1 and Re2, a layer with a large in-plane retardation corresponds to the A layer, and a layer with a small in-plane retardation corresponds to the B layer.
　波長板１が３層構造である場合には、Ｒｔｈａ（ｎｍ）は、ａ層の厚さ方向のリタデーションである。Ｒｔｈｂ（ｎｍ）は、ｂ層の厚さ方向のリタデーションである。Ｒｔｈｃ（ｎｍ）は、ｃ層の厚さ方向のリタデーションである。面内リタデーションＲｅ１、Ｒｅ２およびＲｅ３が大きい層から小さい層の順に、ａ層、ｂ層およびｃ層に該当する。 When the wave plate 1 has a three-layer structure, Rtha (nm) is the retardation in the thickness direction of the a layer. Rthb (nm) is the retardation in the thickness direction of the b layer. Rthc (nm) is the retardation in the thickness direction of the c layer. The layers correspond to the a layer, the b layer and the c layer in order from the layer having the largest in-plane retardation Re1, Re2 and Re3 to the smallest.
　厚さ方向におけるリタデーションＲｔｈａ、Ｒｔｈｂ、Ｒｔｈｃ、ＲｔｈＡ、およびＲｔｈＢは、例えばＡｘｏｍｅｔｒｉｃｓ社のＡｘｏｓｃａｎ装置、または大塚電子社のＲＥ－１００、王子計測株式会社のＫＯＢＲＡ等と、それぞれの装置に付属の解析ソフトと、を用いて測定できる。 Retardations Rtha, Rthb, Rthc, RthA, and RthB in the thickness direction can be obtained, for example, by Axoscan equipment from Axometrics, RE-100 from Otsuka Electronics, KOBRA from Oji Keisoku Co., Ltd., and analysis software attached to each equipment. and can be measured using
　第１の位相差層１１の材料には、例１、例４、例５、例６、例７および例８では材料Ａを、例２および例３では材料Ｂをそれぞれ使用した。第２の位相差層１２の材料には、例１、例３、例５、例６および例８では材料Ｃを、例４および例７では材料Ａを、例２では材料Ｂをそれぞれ使用した。第３の位相差層１３の材料には、例１、例５、例６および例８では材料Ａを、例２では材料Ｂを、例４では材料Ｃをそれぞれ使用した。 As the material of the first retardation layer 11, the material A was used in Examples 1, 4, 5, 6, 7, and 8, and the material B was used in Examples 2 and 3, respectively. As the material of the second retardation layer 12, the material C was used in Examples 1, 3, 5, 6 and 8, the material A was used in Examples 4 and 7, and the material B was used in Example 2. . As the material of the third retardation layer 13, the material A was used in Examples 1, 5, 6, and 8, the material B was used in Example 2, and the material C was used in Example 4, respectively.
　「Δφｃ（°）」は、第１の位相差層１１における光出射側の遅相軸方位角φｃ_ｅ１と、第２の位相差層１２における光入射側の遅相軸方位角φｃ_ｓ２と、のなす角を示す。「Δφｃ（°）」は、遅相軸方位角φｃ_ｅ１と遅相軸方位角φｃ_ｓ２との差分値に対応する。なお、垂直配向している液晶層を含む第２の位相差層１２の遅相軸方位角φｃ_ｓ２は、水平配向又はねじれ配向している液晶層を含む第１の位相差層１１の遅相軸方位角φｃ_ｅ１に対して直交する、すなわち３次元的に直交しているため、「９０°」と表記した。 “Δφc (°)” is defined by the slow axis azimuth angle φc_e1 on the light output side in the first retardation layer 11 and the slow axis azimuth angle φc_s2 on the light incident side in the second retardation layer 12. Show the corners. “Δφc(°)” corresponds to the difference value between the slow axis azimuth angle φc_e1 and the slow axis azimuth angle φc_s2. The slow axis azimuth angle φc_s2 of the second retardation layer 12 including the vertically aligned liquid crystal layer is the slow axis of the first retardation layer 11 including the horizontally aligned or twisted liquid crystal layer. Since it is perpendicular to the azimuth angle φc_e1, that is, it is three-dimensionally perpendicular, it is written as “90°”.
　遅相軸方位角φｃ_ｅ１と遅相軸方位角φｃ_ｓ２とのなす角は、波長板１の三次元座標系においてなす角であってもよい。波長板１の三次元座標系におけるなす角は、三次元的な交差角である。波長板１の三次元座標系は、波長板１の厚さ方向と、該厚さ方向に垂直な面内において直交する２つの方向と、の合計３つの方向により定義される座標系を意味する。 The angle formed by the slow axis azimuth angle φc_e1 and the slow axis azimuth angle φc_s2 may be an angle formed in the three-dimensional coordinate system of the wave plate 1 . The angle formed by the wave plate 1 in the three-dimensional coordinate system is a three-dimensional crossing angle. The three-dimensional coordinate system of the wave plate 1 means a coordinate system defined by a total of three directions, namely, the thickness direction of the wave plate 1 and two orthogonal directions in a plane perpendicular to the thickness direction. .
　図１７Ｂおよび図Ｃ１７は、例１の遅相軸方位角の三次元的な交差角を説明する模式図である。図１７Ｂは、波長板１における第１の位相差層１１、第２の位相差層１２および第３の位相差層１３のそれぞれに含まれる液晶分子の配向の一例を模式的に示している。 17B and C17 are schematic diagrams for explaining the three-dimensional intersection angle of the slow axis azimuth angles of Example 1. FIG. FIG. 17B schematically shows an example of orientation of liquid crystal molecules contained in each of the first retardation layer 11, the second retardation layer 12, and the third retardation layer 13 in the wave plate 1. FIG.
　図１７Ｃは、図１７Ｂに含まれる２つの液晶分子の配向方向の三次元的な交差角を示している。配向方向７１は、第１の位相差層１１に含まれる液晶分子の配向方向を表す。配向方向７２は、第２の位相差層１２に含まれる液晶分子の配向方向を表す。交差角７３は、配向方向７１と配向方向７２との三次元的な交差角を表す。配向方向７１と配向方向７２は直交しており、交差角７３の値は９０度である。交差角７３は、遅相軸方位角φｃ_ｅ１と遅相軸方位角φｃ_ｓ２との三次元的な交差角に対応する。 FIG. 17C shows the three-dimensional intersection angle of the alignment directions of the two liquid crystal molecules included in FIG. 17B. The alignment direction 71 represents the alignment direction of the liquid crystal molecules contained in the first retardation layer 11 . The alignment direction 72 represents the alignment direction of the liquid crystal molecules contained in the second retardation layer 12 . A crossing angle 73 represents a three-dimensional crossing angle between the alignment directions 71 and 72 . The alignment direction 71 and the alignment direction 72 are orthogonal, and the value of the crossing angle 73 is 90 degrees. A crossing angle 73 corresponds to a three-dimensional crossing angle between the slow axis azimuth angle φc_e1 and the slow axis azimuth angle φc_s2.
　「楕円率評価結果」は、楕円率面積の評価結果を示す。「〇」は面積が２５０以上となることを、「×」は面積が２５０未満となることをそれぞれ表す。楕円率面積が２５０以上であれば、広視野角および広帯域において高楕円率となる。 "Ellipticity evaluation result" indicates the evaluation result of the ellipticity area. "O" indicates that the area is 250 or more, and "X" indicates that the area is less than 250. If the ellipticity area is 250 or more, the ellipticity is high in a wide viewing angle and in a wide band.
　表１に示すように、例１、例２、および例６では、第１の位相差層１１に含まれる第１の液晶層１１０および第２の位相差層１２に含まれる第２の液晶層１２０の少なくとも一以上は厚さ方向に液晶分子１１５がねじれて配向しているものとし、遅相軸方位角Δφｃを１０°以上とした。例１から例６では、遅相軸方位角Δφｃを１０°以上とし、２層構造の場合にはリタデーションＲ１およびＲ２を２０ｎｍ以上とし、３層構造の場合には、リタデーションＲ１、Ｒ２およびＲ３を２０ｎｍ以上とした。２層構造の場合におけるＡ層の厚さ方向におけるリタデーションＲｔｈＡ、および３層構造の場合におけるａ層の厚さ方向におけるリタデーションＲｔｈａは正（＞０）とした。 As shown in Table 1, in Examples 1, 2, and 6, the first liquid crystal layer 110 included in the first retardation layer 11 and the second liquid crystal layer included in the second retardation layer 12 In at least one of 120, the liquid crystal molecules 115 are twisted and oriented in the thickness direction, and the azimuth angle Δφc of the slow axis is set to 10° or more. In Examples 1 to 6, the slow axis azimuth angle Δφc is set to 10° or more, the retardations R1 and R2 are set to 20 nm or more in the case of the two-layer structure, and the retardations R1, R2 and R3 are set to the three-layer structure. 20 nm or more. The retardation RthA in the thickness direction of the A layer in the two-layer structure and the retardation Rtha in the thickness direction of the a layer in the three-layer structure were positive (>0).
　一方、例７では、ねじれて配向する液晶分子を有する液晶層を含むものの、遅相軸方位角Δφｃを１０°よりも小さくした。例８では、ねじれて配向した液晶分子を有する液晶層を含まず、Ｒ２＜２０ｎｍとした。 On the other hand, in Example 7, the slow axis azimuth angle Δφc was made smaller than 10° although the liquid crystal layer had liquid crystal molecules that were twisted and aligned. Example 8 does not include a liquid crystal layer with twisted liquid crystal molecules and R2<20 nm.
　楕円率評価結果は、例１から例６では「〇」であり、例７および例８では「×」であった。ここで、楕円率評価において用いた楕円率面積の算出結果を表２に示す。表２に示すように、例１から例６のそれぞれは、例７、例８と比較して大きい楕円率面積が得られた。 The ellipticity evaluation results were "○" for Examples 1 to 6, and "X" for Examples 7 and 8. Here, Table 2 shows the calculation results of the ellipticity area used in the ellipticity evaluation. As shown in Table 2, in each of Examples 1 to 6, a larger ellipticity area than in Examples 7 and 8 was obtained.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　図１８は例１、図１９は例７それぞれにおける楕円率εのコンター図の一例である。図１８および図１９は、波長板１を平面視したときの楕円率分布を表している。 FIG. 18 is an example of a contour diagram of the ellipticity ε in Example 1, and FIG. 19 is an example in Example 7. 18 and 19 show the ellipticity distribution when the wave plate 1 is viewed from above.
　図１８および図１９において、半径方向に沿って表示されている数値の０から５０は、入射角θを表す。周方向に沿って反時計回りに表示されている数値の［０］から［３３０］は、入射方位角ηを表す。入射角θおよび入射方位角ηの単位は、それぞれ［°］である。カラーバーの濃度は、楕円率εの大きさを表している。 In FIGS. 18 and 19, the numerical values 0 to 50 displayed along the radial direction represent the incident angle θ. Numerical values [0] to [330] displayed counterclockwise along the circumferential direction represent incident azimuth angles η. The unit of the incident angle θ and the incident azimuth angle η is [°]. The density of the color bar represents the magnitude of the ellipticity ε.
　図１８に示すように、例１では、０°から５０°の入射角θ、並びに０°から３６０°の入射方位角ηにおいて、全体的に楕円率εが大きくなり、楕円率εの差は小さくなった。 As shown in FIG. 18, in Example 1, the ellipticity ε generally increases at the incident angle θ from 0° to 50° and the incident azimuth angle η from 0° to 360°, and the difference in the ellipticity ε is got smaller.
　一方、図１９に示すように、例７では、入射角θが小さい領域では高い楕円率が得られたが、入射角θが大きくなるにつれて楕円率εが小さくなった。入射方位角ηに応じた楕円率εの差も例１と比較して大きくなった。 On the other hand, as shown in FIG. 19, in Example 7, a high ellipticity was obtained in the region where the incident angle θ was small, but the ellipticity ε decreased as the incident angle θ increased. The difference in ellipticity ε depending on the incident azimuth angle η was also increased compared to Example 1.
　図２０は例１、図２１は例７、それぞれにおける波長λに応じた楕円率εの変化を例示する図である。横軸は波長λを示し、縦軸は楕円率εを示している。入射方位角ηはいずれも０°である。波長λは４００ｎｍから７００ｎｍの範囲、入射角θは０°から７０°の範囲である。また、入射角θに合わせて異なる線種によりグラフが表示されている。 FIG. 20 is an example 1, FIG. 21 is an example 7, and each is a figure which illustrates the change of the ellipticity (epsilon) according to the wavelength (lambda). The horizontal axis indicates the wavelength λ, and the vertical axis indicates the ellipticity ε. Both incident azimuth angles η are 0°. The wavelength λ ranges from 400 nm to 700 nm, and the incident angle θ ranges from 0° to 70°. Also, the graph is displayed with different line types according to the incident angle θ.
　図２０および図２１に示すように、例１では波長λが７００ｎｍにおいて楕円率εが最小の略０．７となり、例７では波長λが４００ｎｍにおいて楕円率εが最小の略０．５２となった。つまり、例１は、例７と比較して楕円率εが全体的に大きくなった。入射角θごとにおける楕円率εの最大値は、例１では略１．０（入射角θが０°のとき）から略０．８８（入射角θが７０°のとき）まで変化した。例７では、略１．０（入射角θが０°のとき）から略０．６１（入射角θが７０°のとき）まで変化した。つまり、例１は、例７と比較して、入射角θに応じた楕円率εの差が小さくなった。 As shown in FIGS. 20 and 21, in Example 1, the ellipticity ε is at a minimum of approximately 0.7 at a wavelength λ of 700 nm, and in Example 7, at a wavelength λ of 400 nm, the ellipticity ε is at a minimum of approximately 0.52. rice field. That is, in Example 1, compared with Example 7, the ellipticity ε was increased as a whole. The maximum value of the ellipticity ε for each incident angle θ varied from about 1.0 (when the incident angle θ was 0°) to about 0.88 (when the incident angle θ was 70°) in Example 1. In Example 7, it varied from about 1.0 (when the incident angle θ was 0°) to about 0.61 (when the incident angle θ was 70°). That is, in Example 1, the difference in ellipticity ε according to the incident angle θ was smaller than in Example 7.
　以上のことから、例１から例６では、例７および例８と比較して、広い入射角および入射方位角において波長板１に入射する光の偏光状態を、高い楕円率により変換できることが分かった。 From the above, it can be seen that in Examples 1 to 6, compared to Examples 7 and 8, the polarization state of light incident on the wave plate 1 can be converted by a high ellipticity at a wide incident angle and incident azimuth angle. rice field.
　また、図２０に示すように、例１では、上に凸となるピークを２つ以下有する。図示しないが、例２～６も同様に、波長４００ｎｍ以上波長７００ｎｍ以下において、上に凸となるピークを2つ以下有する。上記波長範囲で、上に凸となるピークが２つ以下であると、該当の波長範囲での楕円率分布が均一になり、広帯域で同じ楕円率の円偏光が得ることができ、偏光制御が容易になる。 In addition, as shown in FIG. 20, Example 1 has two or less upwardly convex peaks. Although not shown, Examples 2 to 6 similarly have two or less upwardly convex peaks in the wavelength range of 400 nm to 700 nm. If the number of upwardly convex peaks in the above wavelength range is two or less, the ellipticity distribution in the corresponding wavelength range becomes uniform, circularly polarized light with the same ellipticity can be obtained in a wide band, and polarization control is achieved. become easier.
　以上説明したように、本実施形態では、広い入射角および入射方位角において波長板に入射する光の偏光状態を、高い楕円率により変換可能な波長板１を提供できる。 As described above, the present embodiment can provide the wave plate 1 capable of converting the polarization state of light incident on the wave plate over a wide range of incident angles and incident azimuth angles with high ellipticity.
　波長板１は、高い楕円率によって偏光状態を変換することにより、直線偏光Ｐ１を入射する場合には、楕円率がより高い円偏光Ｐ２を出射でき、円偏光Ｐ２を入射する場合には、偏光消光比がより高い直線偏光Ｐ１を出射できる。なお、偏光消光比とは、直交する偏光が分離している程度を表すための指標をいい、例えば直交する偏光であるＰ偏光とＳ偏光の光強度比で表される。 The wavelength plate 1 converts the polarization state with a high ellipticity, so that when the linearly polarized light P1 is incident, it can emit circularly polarized light P2 with a higher ellipticity, and when the circularly polarized light P2 is incident, the polarized light Linearly polarized light P1 with a higher extinction ratio can be emitted. The polarization extinction ratio is an index for expressing the extent to which orthogonally polarized light is separated, and is represented, for example, by the light intensity ratio of P polarized light and S polarized light, which are orthogonal polarized lights.
　本実施形態では、波長板１は積層波長板であるため、製造が容易であり、また波長板の薄型化が可能となる。 In this embodiment, since the wave plate 1 is a laminated wave plate, it is easy to manufacture, and it is possible to make the wave plate thinner.
　（波長板１を備える光学系例）
　実施形態は光学系を含む。例えば、実施形態に係る光学系は、第１の偏光板Ｌ１、第２の偏光板又は第２の波長板Ｑの少なくとも一以上と、波長板１と、を備える。 (Example of optical system including wave plate 1)
Embodiments include optics. For example, the optical system according to the embodiment includes at least one or more of a first polarizing plate L1, a second polarizing plate, or a second wave plate Q, and a wave plate 1.
　第１の偏光板Ｌ１は、波長板１が直線偏光を入射又は出射する側に配置される。第２の波長板Ｑは、波長板１と同じ構成又は波長板１とは異なる構成の何れか一方を有する。第２の偏光板は、第２の波長板Ｑが直線偏光を入射又は出射する側に配置される。 The first polarizing plate L1 is arranged on the side of the wavelength plate 1 on which linearly polarized light is incident or emitted. The second wave plate Q has either the same configuration as the wave plate 1 or a configuration different from the wave plate 1 . The second polarizing plate is arranged on the side of the second wavelength plate Q on which the linearly polarized light is incident or emitted.
　図２２は、実施形態に係る光学系１００の構成を例示する図である。光学系１００は、第１の偏光板Ｌ１を備える。第１の偏光板Ｌ１は、波長板１が直線偏光Ｐ３を入射する側に配置される。第１の偏光板Ｌ１は、ランダム偏光Ｐ１０を入射し、直線偏光Ｐ３を出射する。波長板１は、直線偏光Ｐ３を円偏光Ｐ２に変換する。 FIG. 22 is a diagram illustrating the configuration of the optical system 100 according to the embodiment. The optical system 100 includes a first polarizing plate L1. The first polarizing plate L1 is arranged on the side of the wavelength plate 1 on which the linearly polarized light P3 is incident. The first polarizing plate L1 receives the randomly polarized light P10 and outputs the linearly polarized light P3. Wave plate 1 converts linearly polarized light P3 into circularly polarized light P2.
　第１の偏光板Ｌ１を設けることにより、ランダム偏光Ｐ１０から所望の偏光軸方位角の直線偏光Ｐ３を取り出すことができ、波長板１から出射される光のうち、円偏光Ｐ２の割合をより高くすることができる。なお、波長板１が直線偏光を出射する場合には、第１の偏光板Ｌ１は、波長板１が直線偏光を出射する側に配置される。 By providing the first polarizing plate L1, the linearly polarized light P3 with the desired polarization axis azimuth angle can be extracted from the random polarized light P10, and the proportion of the circularly polarized light P2 in the light emitted from the wave plate 1 can be increased. can do. When the wavelength plate 1 emits linearly polarized light, the first polarizing plate L1 is arranged on the side of the wavelength plate 1 from which the linearly polarized light is emitted.
　第１の偏光板Ｌ１は、図２３に示すように、第１の位相差層１１と接して配置されてもよい。この配置により薄型化した光学系１００を提供できる。また、波長板１と第１の偏光板Ｌ１の間にハーフミラー、基材フィルム、粘着層等別の層があってもよい。 The first polarizing plate L1 may be arranged in contact with the first retardation layer 11 as shown in FIG. This arrangement can provide a thin optical system 100 . Further, another layer such as a half mirror, a base film, an adhesive layer, etc. may be provided between the wavelength plate 1 and the first polarizing plate L1.
　図２４は、実施形態に係る光学系１００ａの構成を例示する図である。光学系１００ａは、第２の偏光板Ｌ２と第２の波長板Ｑを備える。第２の偏光板Ｌ２と第２の波長板Ｑは、波長板１が直線偏光Ｐ４を出射する側とは反対側に配置される。第２の波長板Ｑは、ランダム偏光Ｐ１０を入射した第２の偏光板Ｌ２から出射された直線偏光Ｐ３を入射し、円偏光Ｐ５を出射する。波長板１は、円偏光Ｐ５を直線偏光Ｐ４に変換する。なお、光源自体の偏光度や、求める偏光消光比に応じて第２の偏光板Ｌ２は省略することもできる。 FIG. 24 is a diagram illustrating the configuration of the optical system 100a according to the embodiment. The optical system 100a includes a second polarizing plate L2 and a second wave plate Q. The second polarizing plate L2 and the second wave plate Q are arranged on the side opposite to the side where the wave plate 1 emits the linearly polarized light P4. The second wave plate Q receives the linearly polarized light P3 emitted from the second polarizing plate L2 that receives the randomly polarized light P10, and emits the circularly polarized light P5. Wave plate 1 converts circularly polarized light P5 into linearly polarized light P4. The second polarizing plate L2 can be omitted depending on the degree of polarization of the light source itself and the desired polarization extinction ratio.
　第２の波長板Ｑを備える光学系１００ａでは、波長板１は第１の波長板に対応する。第２の波長板Ｑは、波長板１と同じ構成を有してもよいし、波長板１と異なる構成を有してもよい。 In the optical system 100a including the second wave plate Q, the wave plate 1 corresponds to the first wave plate. The second wave plate Q may have the same configuration as the wave plate 1 or may have a different configuration from the wave plate 1 .
　光学系１００ａは、第２の波長板Ｑを備えることにより、波長板１に円偏光Ｐ５を入射させ、直線偏光Ｐ４を出射させることができる。 By including the second wave plate Q, the optical system 100a can cause the wave plate 1 to receive the circularly polarized light P5 and emit the linearly polarized light P4.
　光学系１００ａは、波長板１における第２の波長板Ｑとは反対側に第１の偏光板Ｌ１を配置することもできる。この構成により、光学系１００ａは、波長板１から出射される直線偏光Ｐ４に第１の偏光板Ｌ１を通過させることにより、直線偏光Ｐ４と比較して偏光消光比がより高い直線偏光を出射できる。 The optical system 100a can also arrange the first polarizing plate L1 on the opposite side of the wave plate 1 to the second wave plate Q. With this configuration, the optical system 100a allows the linearly polarized light P4 emitted from the wave plate 1 to pass through the first polarizing plate L1, thereby allowing the optical system 100a to emit linearly polarized light having a higher polarization extinction ratio than the linearly polarized light P4. .
　第２の波長板Ｑは、図２５に示すように、第２の位相差層１２と接して配置されてもよい。この配置により薄型化した光学系１００ａを提供できる。また、波長板１と第２の波長板Ｑの間にハーフミラー、基材フィルム、粘着層等別の層があってもよい。 The second wave plate Q may be arranged in contact with the second retardation layer 12 as shown in FIG. This arrangement can provide a thin optical system 100a. Further, another layer such as a half mirror, a substrate film, an adhesive layer, etc. may be provided between the wave plate 1 and the second wave plate Q.
　以上のように、本実施形態では、広い入射角および入射方位角で波長板に入射する光の偏光状態を、高い楕円率により変換可能な波長板を備える光学系を提供できる。なお、本実施形態では、第１の位相差層１１と、第２の位相差層１２と、を備える２層構成の波長板１を備える光学系を例示したが、実施形態に係る光学系は、さらに第３の位相差層１３を有する３層構成の波長板１を備えることもできる。この場合には、第３の位相差層１３が円偏光を入射又は出射する。波長板１が３層構成である点以外は、図２２から図２５を参照して説明した光学系１００および１００ａと同様であるため、ここでは重複する説明を省略する。 As described above, in this embodiment, it is possible to provide an optical system having a wave plate capable of converting the polarization state of light incident on the wave plate at a wide incident angle and incident azimuth angle with high ellipticity. In this embodiment, the optical system including the two-layer wave plate 1 including the first retardation layer 11 and the second retardation layer 12 is illustrated, but the optical system according to the embodiment is Further, the wave plate 1 having a three-layer structure having a third retardation layer 13 may be provided. In this case, the third retardation layer 13 receives or emits circularly polarized light. The optical systems 100 and 100a are the same as the optical systems 100 and 100a described with reference to FIGS. 22 to 25, except that the wave plate 1 has a three-layer structure, so redundant description will be omitted here.
　以上、好ましい実施形態について詳説したが、上述した実施形態に制限されることはなく、特許請求の範囲に記載された範囲を逸脱することなく、上述した実施形態に種々の変形および置換を加えることができる。 Although the preferred embodiments have been described in detail above, it is not intended to be limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims. can be done.
　例えば、波長板１を構成する材料として軟質なものを用いることにより、曲げることが可能なフレキシブルな波長板１を提供することもできる。フレキシブルな波長板１は、３次元構造物、特に曲面を有する３次元構造物に好適に貼り付けることができ、直線偏光を円偏光に変換する機能、又は円偏光を直線偏光に変換する機能等を３次元構造物に付与できる。３次元構造物には例えばレンズ、プリズム、ミラー等が挙げられる。レンズには、凹面を含む凹レンズ、又は凸面を含む凸レンズ等が含まれる。 For example, by using a soft material for the wave plate 1, it is possible to provide a flexible wave plate 1 that can be bent. The flexible wave plate 1 can be preferably attached to a three-dimensional structure, particularly a three-dimensional structure having a curved surface, and has a function of converting linearly polarized light into circularly polarized light, or a function of converting circularly polarized light into linearly polarized light. can be applied to the three-dimensional structure. Three-dimensional structures include, for example, lenses, prisms, mirrors, and the like. A lens includes a concave lens including a concave surface, a convex lens including a convex surface, and the like.
　３次元構造物は、液晶ディスプレイ又は有機ＥＬディスプレイなどの表示装置であってもよい。また、曲面を有する３次元構造物は、液晶ディスプレイ又は有機ＥＬディスプレイなどが曲面を有する曲面表示装置（曲面ディスプレイ）であってもよい。 The three-dimensional structure may be a display device such as a liquid crystal display or an organic EL display. Also, the three-dimensional structure having a curved surface may be a curved display device (curved display) such as a liquid crystal display or an organic EL display.
　実施形態に係る波長板および光学系は、液晶ディスプレイ又は有機ＥＬディスプレイ等の表示装置、偏光測定装置等の光学測定装置、或いは光ヘッド等の光学的手法を用いる多様な分野に適用できる。換言すると、実施形態では、広い入射角および入射方位角で波長板に入射する光の偏光状態を、高い楕円率により変換可能な光学系を備える表示装置を提供できる。 The wave plate and optical system according to the embodiments can be applied to various fields using optical techniques such as display devices such as liquid crystal displays or organic EL displays, optical measurement devices such as polarization measurement devices, or optical heads. In other words, in the embodiments, it is possible to provide a display device having an optical system capable of converting the polarization state of light incident on the wave plate at a wide incident angle and incident azimuth angle with high ellipticity.
　この出願は、２０２１年９月２４日に日本国特許庁に出願された日本国特許出願第２０２１－１５５８２９号、および、２０２２年２月９日に日本国特許庁に出願された日本国特許出願第２０２２－０１９１１８号に基づいて、その優先権を主張するものであり、これらの日本国特許出願の全内容を含む。 This application is the Japanese Patent Application No. 2021-155829 filed with the Japan Patent Office on September 24, 2021, and the Japanese Patent Application filed with the Japan Patent Office on February 9, 2022 Based on No. 2022-019118, it claims priority and includes the entire contents of these Japanese patent applications.
１　　　波長板
１０　　境界面
１１　　第１の位相差層
１１０　第１の液晶層
１１１　入射側基板
１１２　入射側配向層
１１３　出射側基板
１１４　出射側配向層
１１５　液晶分子
１１６　遅相軸
１２　　第２の位相差層
１２０　第２の液晶層
１３　　第３の位相差層
１３０　第３の液晶層
１００、１００ａ、１００ｂ、１００ｃ　光学系
Ｌ１　　第１の偏光板
Ｌ２　　第２の偏光板
ｎｅ　　異常光屈折率
ｎｏ　　常光屈折率
Ｐ１、Ｐ３、Ｐ４、Ｐ６、Ｐ７　直線偏光
Ｐ２、Ｐ５　円偏光
Ｐ１０　ランダム偏光
Ｑ　　　第２の波長板
ＲｅＡ　第１の位相差層の波長５５０ｎｍにおける面内リタデーション
ＲｅＢ　第２の位相差層の波長５５０ｎｍにおける面内リタデーション
φ０　　偏光軸方位角
φｃ　　遅相軸方位角
Δφｃ　遅相軸方位角
θ　　　入射角
ε　　　楕円率
η　　　入射方位角
λ　　　波長
Δλ　　波長幅 1 wave plate 10 interface 11 first retardation layer 110 first liquid crystal layer 111 incident side substrate 112 incident side alignment layer 113 exit side substrate 114 exit side alignment layer 115 liquid crystal molecules 116 slow axis 12 second phase difference Layer 120 Second liquid crystal layer 13 Third retardation layer 130 Third liquid crystal layer 100, 100a, 100b, 100c Optical system L1 First polarizing plate L2 Second polarizing plate ne Extraordinary refractive index no Ordinary refractive index P1, P3, P4, P6, P7 Linearly polarized light P2, P5 Circularly polarized light P10 Randomly polarized light Q Second wave plate ReA In-plane retardation ReB of the second retardation layer at a wavelength of 550 nm In-plane retardation φ0 Polarization axis azimuth φc Slow axis azimuth Δφc Slow axis azimuth θ Incidence angle ε Ellipticity η Incident azimuth λ Wavelength Δλ Wavelength width

Claims (24)

  1. 　第１の位相差層および第２の位相差層を備え、前記第１の位相差層側から直線偏光を入射して前記第２の位相差層側から円偏光を出射し、又は、前記第２の位相差層側から円偏光を入射して前記第１の位相差層側から直線偏光を出射する波長板であって、
    　前記第１の位相差層は、第１の液晶層を含み、
    　前記第２の位相差層は、第２の液晶層を含み、
    　前記第１の液晶層および前記第２の液晶層の少なくとも一以上は、厚さ方向に液晶分子がねじれて配向しており、
    　前記波長板の三次元座標系において、前記第１の位相差層における前記第２の位相差層側の遅相軸と、前記第２の位相差層における前記第１の位相差層側の遅相軸と、がなす角が１０°以上である、波長板。     A first retardation layer and a second retardation layer are provided, and linearly polarized light is incident from the first retardation layer side and circularly polarized light is emitted from the second retardation layer side, or A wave plate for entering circularly polarized light from the second retardation layer side and emitting linearly polarized light from the first retardation layer side,
    The first retardation layer includes a first liquid crystal layer,
    The second retardation layer includes a second liquid crystal layer,
    At least one of the first liquid crystal layer and the second liquid crystal layer has liquid crystal molecules twisted and aligned in a thickness direction,
    In the three-dimensional coordinate system of the wave plate, the slow axis of the first retardation layer on the side of the second retardation layer and the slow axis of the second retardation layer on the side of the first retardation layer A wave plate forming an angle of 10° or more with respect to the phase axis.
  2. 　前記第１の位相差層の波長５５０ｎｍにおけるリタデーションＲ１および前記第２の位相差層の波長５５０ｎｍにおけるリタデーションＲ２は、それぞれ２０ｎｍ以上であり、
    　Ｒ１およびＲ２を比較したとき、大きい方の厚さ方向のリタデーションＲｔｈＡは正である、請求項１に記載の波長板。     The retardation R1 at a wavelength of 550 nm of the first retardation layer and the retardation R2 at a wavelength of 550 nm of the second retardation layer are each 20 nm or more,
    2. The waveplate of claim 1, wherein the larger through-thickness retardation RthA is positive when R1 and R2 are compared.
  3. 　第３の液晶層を含む第３の位相差層をさらに備え、
    　前記直線偏光を入射又は出射する側から、前記第１の位相差層、前記第２の位相差層、および前記第３の位相差層がこの順に積層され、
    　前記第１の位相差層の波長５５０ｎｍにおけるリタデーションＲ１、前記第２の位相差層のリタデーションＲ２、および前記第３の位相差層の波長５５０ｎｍにおけるリタデーションＲ３が２０ｎｍ以上であり、
    　Ｒ１、Ｒ２およびＲ３を比較したとき、一番大きい厚さ方向のリタデーションＲｔｈａは正である、請求項１に記載の波長板。     further comprising a third retardation layer including a third liquid crystal layer;
    The first retardation layer, the second retardation layer, and the third retardation layer are laminated in this order from the side on which the linearly polarized light is incident or emitted,
    The retardation R1 at a wavelength of 550 nm of the first retardation layer, the retardation R2 of the second retardation layer, and the retardation R3 at a wavelength of 550 nm of the third retardation layer are 20 nm or more,
    2. The waveplate of claim 1, wherein the largest through-thickness retardation Rtha is positive when R1, R2 and R3 are compared.
  4. 　第１の位相差層および第２の位相差層を備え、前記第１の位相差層側から直線偏光を入射して前記第２の位相差層側から円偏光を出射し、又は、前記第２の位相差層側から円偏光を入射して前記第１の位相差層側から直線偏光を出射する波長板であって、
    　前記第１の位相差層は、第１の液晶層を含み、
    　前記第２の位相差層は、第２の液晶層を含み、
    　前記第１の位相差層の波長５５０ｎｍにおけるリタデーションＲ１および前記第２の位相差層の波長５５０ｎｍにおけるリタデーションＲ２は、それぞれ２０ｎｍ以上であり、
    　Ｒ１およびＲ２を比較したとき、大きい方の厚さ方向のリタデーションＲｔｈＡは正である、波長板。     A first retardation layer and a second retardation layer are provided, and linearly polarized light is incident from the first retardation layer side and circularly polarized light is emitted from the second retardation layer side, or A wave plate for entering circularly polarized light from the second retardation layer side and emitting linearly polarized light from the first retardation layer side,
    The first retardation layer includes a first liquid crystal layer,
    The second retardation layer includes a second liquid crystal layer,
    The retardation R1 at a wavelength of 550 nm of the first retardation layer and the retardation R2 at a wavelength of 550 nm of the second retardation layer are each 20 nm or more,
    A wave plate wherein the larger through-thickness retardation RthA is positive when R1 and R2 are compared.
  5. 　第１の位相差層、第２の位相差層、および第３の位相差層をこの順に備え、前記第１の位相差層側から直線偏光を入射して前記第３の位相差層側から円偏光を出射し、又は、前記第３の位相差層側から円偏光を入射して前記第１の位相差層側から直線偏光を出射する波長板であって、
    　前記第１の位相差層は、第１の液晶層を含み、
    　前記第２の位相差層は、第２の液晶層を含み、
    　前記第３の位相差層は、第３の液晶層を含み、
    　前記第１の位相差層の波長５５０ｎｍにおけるリタデーションＲ１、前記第２の位相差層の波長５５０ｎｍにおけるリタデーションＲ２、および前記第３の位相差層の波長５５０ｎｍにおけるリタデーションＲ３は、それぞれ２０ｎｍ以上であり、
    　Ｒ１、Ｒ２およびＲ３を比較したとき、一番大きい厚さ方向のリタデーションＲｔｈａは正である、波長板。     A first retardation layer, a second retardation layer, and a third retardation layer are provided in this order, and linearly polarized light is incident from the first retardation layer side and from the third retardation layer side A wave plate that emits circularly polarized light, or that emits circularly polarized light from the third retardation layer side and emits linearly polarized light from the first retardation layer side,
    The first retardation layer includes a first liquid crystal layer,
    The second retardation layer includes a second liquid crystal layer,
    The third retardation layer includes a third liquid crystal layer,
    The retardation R1 at a wavelength of 550 nm of the first retardation layer, the retardation R2 at a wavelength of 550 nm of the second retardation layer, and the retardation R3 at a wavelength of 550 nm of the third retardation layer are each 20 nm or more,
    A wave plate wherein the largest through-thickness retardation Rtha is positive when comparing R1, R2 and R3.
  6. 　前記第１の液晶層および前記第２の液晶層の少なくとも一以上は、厚さ方向に液晶分子がねじれて配向している、請求項４又は請求項５に記載の波長板。 The wavelength plate according to claim 4 or 5, wherein at least one of the first liquid crystal layer and the second liquid crystal layer has liquid crystal molecules twisted and aligned in the thickness direction.
  7. 　前記第３の液晶層は、厚さ方向に液晶分子がねじれて配向している、請求項３又は請求項５に記載の波長板。 The wavelength plate according to claim 3 or 5, wherein the third liquid crystal layer has liquid crystal molecules twisted and oriented in the thickness direction.
  8. 　前記波長板は、積層波長板である、請求項１～７のいずれか１項に記載の波長板。 The wave plate according to any one of claims 1 to 7, wherein the wave plate is a laminated wave plate.
  9. 　請求項１～８のいずれか１項に記載の波長板と、
    　前記波長板が前記直線偏光を入射又は出射する側に配置される第１の偏光板と、を備える、光学系。     A wave plate according to any one of claims 1 to 8;
    and a first polarizing plate arranged on a side where the wave plate enters or emits the linearly polarized light.
  10. 　前記第１の偏光板は、前記第１の位相差層又は前記第２の位相差層と接する、請求項９に記載の光学系。 The optical system according to claim 9, wherein the first polarizing plate is in contact with the first retardation layer or the second retardation layer.
  11. 　前記波長板は、第３の液晶層を含む第３の位相差層を備え、
    　前記第１の偏光板は、前記第１の位相差層又は前記第３の位相差層と接する、請求項１０に記載の光学系。     The wave plate comprises a third retardation layer containing a third liquid crystal layer,
    11. The optical system according to claim 10, wherein said first polarizing plate is in contact with said first retardation layer or said third retardation layer.
  12. 　請求項１～７のいずれか１項に記載の波長板からなる第１の波長板と、
    　前記第１の波長板と同じ構成又は前記第１の波長板とは異なる構成の何れか一方を有する第２の波長板と、を備える、請求項９～１１のいずれか１項に記載の光学系。     A first wave plate made of the wave plate according to any one of claims 1 to 7;
    and a second wave plate having either the same configuration as the first wave plate or a configuration different from the first wave plate. system.
  13. 　前記第２の波長板は、前記第１の波長板と同じ構成を有する、請求項１２に記載の光学系。 The optical system according to claim 12, wherein the second wave plate has the same configuration as the first wave plate.
  14. 　前記第２の波長板が前記直線偏光を入射又は出射する側に配置される第２の偏光板をさらに備える、請求項１２又は１３に記載の光学系。 14. The optical system according to claim 12 or 13, further comprising a second polarizing plate arranged on the side where the second wave plate enters or emits the linearly polarized light.
  15. 　請求項９～１４のいずれか１項に記載の光学系を備える表示装置。 A display device comprising the optical system according to any one of claims 9 to 14.
  16. 　第１の位相差層、第２の位相差層および第３の位相差層と、これらを支持する基板とを備え、
    　前記第１の位相差層は、第１の液晶層を含み、
    　前記第２の位相差層は、第２の液晶層を含み、
    　前記第３の位相差層は、第３の液晶層を含み、
    　前記第１の液晶層および前記第３の液晶層は、前記基板の面に対して液晶分子が平行方向に配向しており、
    　前記第１の液晶層および前記第３の液晶層は、いずれも厚さ方向に液晶分子がねじれて配向しており、
    　前記第２の液晶層は、厚さ方向に液晶分子が垂直に配向しており、
    　第１の位相差層および第３の位相差層は、いずれも微小な１次元格子状の溝からなる配向層を含み、
    　直線偏光を入射させる側から、第１の位相差層、第２の位相差層、第３の位相差層の順に積層された波長板。     A first retardation layer, a second retardation layer and a third retardation layer, and a substrate supporting them,
    The first retardation layer includes a first liquid crystal layer,
    The second retardation layer includes a second liquid crystal layer,
    The third retardation layer includes a third liquid crystal layer,
    In the first liquid crystal layer and the third liquid crystal layer, liquid crystal molecules are oriented parallel to the surface of the substrate,
    In both the first liquid crystal layer and the third liquid crystal layer, liquid crystal molecules are twisted and aligned in the thickness direction,
    The second liquid crystal layer has liquid crystal molecules aligned vertically in the thickness direction,
    Both the first retardation layer and the third retardation layer include an orientation layer consisting of fine one-dimensional lattice-like grooves,
    A wave plate in which a first retardation layer, a second retardation layer, and a third retardation layer are laminated in this order from the side on which linearly polarized light is incident.
  17. 　前記基板に対して液晶分子が平行方向に配向している場合を０°、前記基板の法線に対して液晶分子が平行方向に配向している場合を９０°と定義したチルト角が０°以上２°未満であり、
    　前記第１の液晶層および前記第３の液晶層の液晶分子のねじれの方向が同一であり、
    　前記第１の液晶層、前記第２の液晶層および前記第３の液晶層はいずれも正分散の液晶分子からなり、
    　前記基板の三次元座標系において、前記第１の位相差層における前記第３の位相差層側の遅相軸と、前記第２の位相差層の遅相軸と、のなす角は９０°であり、
    　前記基板の三次元座標系において、前記第３の位相差層における前記第１の位相差層側の遅相軸と、前記第２の位相差層の遅相軸と、のなす角は９０°であり、
    　前記基板の三次元座標系において、前記第３の位相差層における前記第１の位相差層側の遅相軸と、前記第１の位相差層における前記第３の位相差層側の遅相軸と、のなす角は０°より大きく２°未満である、請求項１６に記載の波長板。     The tilt angle is defined as 0° when the liquid crystal molecules are oriented parallel to the substrate, and 90° when the liquid crystal molecules are oriented parallel to the normal to the substrate. greater than or equal to less than 2°,
    twist directions of liquid crystal molecules in the first liquid crystal layer and the third liquid crystal layer are the same;
    the first liquid crystal layer, the second liquid crystal layer, and the third liquid crystal layer are all composed of liquid crystal molecules with positive dispersion;
    In the three-dimensional coordinate system of the substrate, the angle between the slow axis of the first retardation layer on the side of the third retardation layer and the slow axis of the second retardation layer is 90°. and
    In the three-dimensional coordinate system of the substrate, the angle formed by the slow axis of the third retardation layer on the side of the first retardation layer and the slow axis of the second retardation layer is 90°. and
    In the three-dimensional coordinate system of the substrate, the slow axis on the first retardation layer side in the third retardation layer and the slow phase on the third retardation layer side in the first retardation layer 17. The waveplate of claim 16, wherein the angle between the axis is greater than 0[deg.] and less than 2[deg.].
  18. 　前記第１の位相差層の波長５５０ｎｍにおける面内リタデーションが２８０ｎｍ以上３００ｎｍ以下であり、
    　前記第２の位相差層の波長５５０ｎｍにおける面内リタデーションが１５ｎｍ以下であり、
    　前記第３の位相差層の波長５５０ｎｍにおける面内リタデーションが１３０ｎｍ以上１５０ｎｍ以下である、請求項１６又は請求項１７に記載の波長板。     The in-plane retardation of the first retardation layer at a wavelength of 550 nm is 280 nm or more and 300 nm or less,
    The in-plane retardation of the second retardation layer at a wavelength of 550 nm is 15 nm or less,
    The wave plate according to claim 16 or 17, wherein the in-plane retardation of the third retardation layer at a wavelength of 550 nm is 130 nm or more and 150 nm or less.
  19. 　前記第１の位相差層の波長５５０ｎｍにおける面内リタデーションが３１０ｎｍ以上３３５ｎｍ以下であり、
    　前記第２の位相差層の波長５５０ｎｍにおける面内リタデーションが１７ｎｍ以下であり、
    　前記第３の位相差層の波長５５０ｎｍにおける面内リタデーションが１４０ｎｍ以上１７ｎｍ以下である、請求項１６又は請求項１７に記載の波長板。     The in-plane retardation of the first retardation layer at a wavelength of 550 nm is 310 nm or more and 335 nm or less,
    The in-plane retardation of the second retardation layer at a wavelength of 550 nm is 17 nm or less,
    18. The wave plate according to claim 16, wherein the in-plane retardation of the third retardation layer at a wavelength of 550 nm is 140 nm or more and 17 nm or less.
  20. 　前記第１の位相差層及び前記第３の位相差層のＲｔｈが正であり、
    　前記第２の位相差層のＲｔｈが負である、請求項１６から請求項１９のいずれか１項に記載の波長板。     Rth of the first retardation layer and the third retardation layer is positive,
    20. The wave plate according to any one of claims 16 to 19, wherein Rth of said second retardation layer is negative.
  21. 　前記第２の位相差層のＲｔｈは、－１５０ｎｍ以上－８０ｎｍ以下である、請求項２０に記載の波長板。 The wave plate according to claim 20, wherein Rth of the second retardation layer is -150 nm or more and -80 nm or less.
  22. 　曲面を有する３次元構造物を含み、
    　前記３次元構造物の中心から１０ｍｍの位置の前記基板の厚みは、前記３次元構造物の中心における前記基板の厚みの１.０倍以上１.２倍以下である、請求項１６～２１のいずれか１項に記載の波長板。     including a three-dimensional structure having a curved surface,
    The thickness of the substrate at a position 10 mm from the center of the three-dimensional structure is 1.0 times or more and 1.2 times or less than the thickness of the substrate at the center of the three-dimensional structure. A wave plate according to any one of claims 1 to 3.
  23. 　曲面を有する３次元構造物を含み、
    　前記３次元構造物の中心から１３ｍｍの位置の前記基板の厚みは、前記３次元構造物の中心における前記基板の厚みの１.０倍以上１.２倍以下である、請求項１６～２１のいずれか１項に記載の波長板。     including a three-dimensional structure having a curved surface,
    The thickness of the substrate at a position 13 mm from the center of the three-dimensional structure is 1.0 times or more and 1.2 times or less than the thickness of the substrate at the center of the three-dimensional structure. A wave plate according to any one of claims 1 to 3.
  24. 　曲面を有する３次元構造物を含み、
    　前記３次元構造物の中心から１５ｍｍの位置の前記基板の厚みは、前記３次元構造物の中心における前記基板の厚みの１.０倍以上１.２倍以下である、請求項１６～２１のいずれか１項に記載の波長板。     including a three-dimensional structure having a curved surface,
    The thickness of the substrate at a position 15 mm from the center of the three-dimensional structure is 1.0 times or more and 1.2 times or less than the thickness of the substrate at the center of the three-dimensional structure. A wave plate according to any one of claims 1 to 3.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116931325A (en) * 2023-07-26 2023-10-24 成都瑞波科材料科技有限公司 Curved surface compensation film and preparation method thereof

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10227914A (en) * 1996-12-12 1998-08-25 Sekisui Chem Co Ltd Optical element and liquid crystal display element
JP2003215341A (en) * 2002-01-25 2003-07-30 Nippon Oil Corp Circularly polarizing plate and liquid crystal display
JP2004309904A (en) * 2003-04-09 2004-11-04 Nitto Denko Corp Circular polarization plate, luminance improvement film, and image display device
JP2006201746A (en) * 2004-12-22 2006-08-03 Nitto Denko Corp Elliptic polarizing plate and image display device using the same
WO2014157079A1 (en) * 2013-03-25 2014-10-02 富士フイルム株式会社 Circularly polarizing plate, retardation plate for circularly polarizing plate, and organic el display device

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10227914A (en) * 1996-12-12 1998-08-25 Sekisui Chem Co Ltd Optical element and liquid crystal display element
JP2003215341A (en) * 2002-01-25 2003-07-30 Nippon Oil Corp Circularly polarizing plate and liquid crystal display
JP2004309904A (en) * 2003-04-09 2004-11-04 Nitto Denko Corp Circular polarization plate, luminance improvement film, and image display device
JP2006201746A (en) * 2004-12-22 2006-08-03 Nitto Denko Corp Elliptic polarizing plate and image display device using the same
WO2014157079A1 (en) * 2013-03-25 2014-10-02 富士フイルム株式会社 Circularly polarizing plate, retardation plate for circularly polarizing plate, and organic el display device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116931325A (en) * 2023-07-26 2023-10-24 成都瑞波科材料科技有限公司 Curved surface compensation film and preparation method thereof
CN116931325B (en) * 2023-07-26 2024-05-28 成都瑞波科材料科技有限公司 Curved surface compensation film and preparation method thereof

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