WO2005081051A1 - Liquid crystal optical modulating device - Google Patents

Liquid crystal optical modulating device Download PDF

Info

Publication number
WO2005081051A1
WO2005081051A1 PCT/JP2005/002611 JP2005002611W WO2005081051A1 WO 2005081051 A1 WO2005081051 A1 WO 2005081051A1 JP 2005002611 W JP2005002611 W JP 2005002611W WO 2005081051 A1 WO2005081051 A1 WO 2005081051A1
Authority
WO
WIPO (PCT)
Prior art keywords
liquid crystal
voltage
light
incident light
wavelength
Prior art date
Application number
PCT/JP2005/002611
Other languages
French (fr)
Japanese (ja)
Inventor
Takuji Nomura
Atsushi Koyanagi
Original Assignee
Asahi Glass Company, Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Asahi Glass Company, Limited filed Critical Asahi Glass Company, Limited
Priority to JP2006510250A priority Critical patent/JPWO2005081051A1/en
Publication of WO2005081051A1 publication Critical patent/WO2005081051A1/en

Links

Classifications

    • 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
    • G02F1/137—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 characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering
    • G02F1/13718—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 characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering based on a change of the texture state of a cholesteric liquid crystal
    • 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
    • G02F1/1343—Electrodes
    • G02F1/134309—Electrodes characterised by their geometrical arrangement
    • 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
    • G02F1/137—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 characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering
    • G02F1/13775—Polymer-stabilized liquid crystal layers

Definitions

  • the present invention relates to a liquid crystal light modulation element for controlling light transmittance, a state of a wavefront, and the like in an optical system using a semiconductor laser, and more particularly, to a liquid crystal light modulation element used for optical communication, an optical head device, or the like.
  • a liquid crystal light modulation element for controlling light transmittance, a state of a wavefront, and the like in an optical system using a semiconductor laser, and more particularly, to a liquid crystal light modulation element used for optical communication, an optical head device, or the like.
  • a cholesteric liquid crystal or a nematic liquid crystal containing a chiral agent has a broadly defined cholesteric liquid crystal structure in which liquid crystal molecules 10 have a helical twisted orientation as shown in the schematic diagram of FIG. Collectively, it is simply called "cholesteric liquid crystal".
  • the voltage application response of these cholesteric liquid crystals is as follows.
  • the liquid crystal molecules are oriented in a substantially horizontal direction, and a helical axis is oriented in a direction perpendicular to the substrate in a planar state.
  • Non-Patent Document 1 As an example of an element using a cholesteric liquid crystal, for example, there is a display element utilizing light scattering characteristics in a focal conic state (for example, see Non-Patent Document 1).
  • a display element utilizing light scattering characteristics in a focal conic state for example, see Non-Patent Document 1.
  • a liquid crystal shutter using light scattering characteristics in a focal conic state for example, see Patent Document 1
  • FIG. 1 shows an example of the configuration.
  • the optical attenuator 200 shown in FIG. 1 has a cholesteric liquid crystal layer 1 having a helical structure as shown in FIG. 2 between a substrate 5 and a substrate 6 on which electrodes 3 and 4 for voltage application are formed.
  • the liquid crystal cell 110 which is held so that its helical axis is perpendicular to the substrates 5 and 6 and is hermetically sealed with the sealing material 2, and the light exit surface side of the liquid crystal cell 110,
  • a polarizer 7 that selectively transmits linearly polarized light in the same direction as the polarization direction is arranged.
  • the polarization direction of the incident light is indicated by reference numeral 9 in FIG.
  • the reason that the allowable amount of variation in the thickness of the optical disc is reduced is that the spherical aberration, which is one of the wavefront aberrations, occurs in proportion to the variation in the thickness of the optical disc, and the light-collecting characteristics of the optical head device deteriorate. This makes it difficult to read signals.
  • the following methods have been proposed as means for correcting spherical aberration.
  • the first method is to mechanically change the position of the collimating lens in accordance with the amount of generated spherical aberration, to generate spherical aberration between the collimating lens and the objective lens, and to generate the optical disk thickness error.
  • There is a method for canceling spherical aberration hereinafter referred to as a mechanical method.
  • mechanical method Since a movable part for mechanically moving the mate lens (hereinafter referred to as a mechanical movable part) is required, there is a disadvantage that the configuration of the optical head device becomes complicated or large.
  • Patent Document 1 Japanese Patent Application Laid-Open No. Hei 4 260024
  • Patent Document 2 JP-A-10-20263
  • Non-patent Document 1 Liquid Crystal Handbook Editing Committee, ⁇ LCD Handbook Chapter 5 '', Maruzen Co., Ltd., 2000
  • phase correction element In the phase correction element disclosed in Patent Document 2, a nematic liquid crystal or a twisted nematic (TN) liquid crystal is used, so that the phase in the polarization direction of the incident light is changed.
  • Dependent polarization state dependence occurs.
  • the wavelength of the light source is short, about 405 nm, it is not sufficient to correct the wavefront aberration of the light emitted from the light source, and it is necessary to correct the wavefront aberration of the light reflected by the optical recording medium.
  • a method of removing or reducing the polarization state dependency a method of using two layers of phase correction elements is conceivable, but there is a problem that the element configuration becomes complicated.
  • the present invention has been made to solve such a problem.
  • a liquid crystal light modulation element using a cholesteric liquid crystal a light scattering state caused by the appearance of a focal conic state in a voltage application process and a voltage cutoff process.
  • a liquid crystal light modulation element in which no light is generated is provided.
  • the present invention has the following gist.
  • a liquid crystal light modulation device that performs modulation on the liquid crystal layer, wherein the liquid crystal layer is formed by polymerizing a liquid crystal composition containing a cholesteric liquid crystal, a non-liquid crystal monofunctional polymerizable monomer, and a liquid crystal polyfunctional polymerizable monomer.
  • a liquid crystal light modulation element comprising a polymer stable cholesteric liquid crystal, wherein a light scattering state does not occur due to the appearance of a focal conic state in both a voltage application process and a voltage cutoff process.
  • a liquid crystal light modulation device using the cholesteric liquid crystal, a liquid crystal light modulation device can be realized in which the light scattering state due to the appearance of the focal conic state does not occur during the voltage application process and the voltage cutoff process.
  • the polymer-stabilized cholesteric liquid crystal is compared with the non-liquid crystal monomer in the total amount of the cholesteric liquid crystal, the non-liquid crystal monofunctional polymerizable monomer, and the liquid crystal polyfunctional polymerizable monomer in the liquid crystal composition.
  • the polymer-stabilized cholesteric liquid crystal obtained by polymerizing a liquid crystal composition containing 115% by mass of a functional polymerizable monomer and 3 to 7% by mass of a liquid crystalline polyfunctional polymerizable monomer. 3.
  • the liquid crystal light modulation device according to item 1.
  • the liquid crystal light modulating element further comprises a polarization selecting means for selectively transmitting linearly polarized light in a predetermined direction on a light exit surface side thereof, and the liquid crystal layer has a selective reflection wavelength of the liquid crystal light modulating light.
  • the angle of optical rotation when the incident light is transmitted is within a range of more than 0 ° and less than 180 °, and the application of voltage to the electrode and the The liquid crystal light modulation device of the above 1 or 2, wherein the transmittance of the incident light changes depending on the application.
  • the optical rotation angle can be changed in accordance with the magnitude of the applied voltage, so that a liquid crystal light modulation element that can control the amount of transmitted light can be realized.
  • the amount of transmitted light can be continuously changed by continuously changing the applied voltage.
  • the selective reflection wavelength is shorter than the wavelength of the incident light of the liquid crystal modulation element, and the optical rotation angle when the incident light is transmitted when no voltage is applied is substantially zero.
  • At least one of the electrodes is formed so as to generate an inter-substrate voltage distribution in the substrate plane, and changes in the liquid crystal layer according to the inter-substrate voltage distribution.
  • the liquid crystal light modulation device according to the above 1 or 2, wherein the wavefront of the incident light is changed by causing a refractive index to occur.
  • the liquid crystal light modulator that can correct the wavefront aberration by changing the phase by changing the refractive index of the liquid crystal layer according to the magnitude of the applied voltage depends on the polarization state. Can be realized without gender.
  • a liquid crystal modulation element using a cholesteric liquid crystal, in which a light scattering state due to the appearance of a focal conic state does not occur in a voltage application process and a voltage cutoff process.
  • FIG. 1 is a side view showing an example of a configuration of a liquid crystal light modulation element (optical attenuator) according to an embodiment of the present invention, and an example of a configuration of a conventional liquid crystal light modulation element (optical attenuator).
  • FIG. 1 is a side view showing an example of a configuration of a liquid crystal light modulation element (optical attenuator) according to an embodiment of the present invention, and an example of a configuration of a conventional liquid crystal light modulation element (optical attenuator).
  • FIG. 2 is a diagram conceptually showing a molecular arrangement of a cholesteric liquid crystal.
  • FIG. 3 is a graph of measurement results showing the wavelength dependence of the optical rotation angle, ellipticity, and transmittance of the experimental liquid crystal cell.
  • FIG. 4 is a conceptual diagram showing spherical aberration when 0.03 mm of thickness unevenness occurs on an optical disc.
  • FIG. 5 is a schematic view showing an electrode pattern of a liquid crystal light modulation element (phase correction element) according to an example of the present invention.
  • the liquid crystal light modulation device is used in an optical system using a light source such as a semiconductor laser, and includes a pair of opposed substrates, and electrodes formed on opposed surfaces of each substrate, And a liquid crystal layer sandwiched between the pair of opposing substrates.
  • a light source such as a semiconductor laser
  • a substrate constituting the liquid crystal light modulation element for example, an acrylic resin, an epoxy resin, a salt-based butyl resin, or a polycarbonate may be used. Is preferred.
  • a known spacer such as a glass fiber or a plastic bead is interposed between the substrates in order to maintain a predetermined thickness in the liquid crystal layer sandwiched between the pair of substrates.
  • a horizontal alignment film is formed on the surface of the substrate sandwiching the liquid crystal layer, a planar state in which the helical axis of the cholesteric liquid crystal is oriented in a direction perpendicular to the substrate can be easily realized. Therefore, it is suitable.
  • Polyimide or the like can be used as a material for the alignment film. Further, it is also preferable to perform a rubbing treatment on the horizontal alignment film so as to uniformly align the liquid crystal molecules near the substrate interface.
  • an oxide film made of indium tin oxide (ITO) or a metal film having a strong force such as Au or A1 can be used. It is suitable because it has good permeability and good mechanical durability.
  • the liquid crystal layer is composed of a polymer stabilized cholesteric liquid crystal obtained by polymerizing a liquid crystal composition including a cholesteric liquid crystal, a non-liquid crystal monofunctional polymerizable monomer, and a liquid crystal polyfunctional polymerizable monomer. Layer.
  • a nematic liquid crystal (chiral nematic liquid crystal) containing a cholesteric liquid crystal / chiral agent can be used.
  • concentration of the chiral agent by adjusting the concentration of the chiral agent, the wavelength of light that is selectively reflected (hereinafter, referred to as “selective reflection wavelength”) can be adjusted.
  • a commercially available nematic liquid crystal used for a liquid crystal display device may be used.
  • a nematic liquid crystal having a structure containing 2 to 4 benzene rings and cyclohexane rings is exemplified.
  • the liquid crystal preferably has a substituent such as a fluorine atom or a cyano group.
  • a chiral agent is an optically active substance having an asymmetric carbon and does not necessarily have to exhibit liquid crystallinity, but has high compatibility with a nematic liquid crystal and a high twisting power (HTP). Material is desirable ⁇ .
  • HTP lZ (P'C) between the torsional force (HTP), the helical pitch (P), and the chiral agent concentration (C).
  • the spiral pitch can be reduced by using a spiral agent.
  • a mixture of a plurality of chiral agents may be used to reduce the temperature dependence of the helical pitch.
  • the non-liquid crystalline monofunctional polymerizable monomer used to obtain the above liquid crystal layer includes one Is a non-liquid crystalline compound having a polymerizable functional group.
  • the monomer is preferably a compound having one atalyloyl group or methacryloyl group (preferably atariloyl group), but non-liquid crystalline acrylates and non-liquid crystalline methacrylates are preferred. Non-liquid crystalline acrylates are particularly preferred.
  • the liquid crystalline polyfunctional polymerizable monomer is a liquid crystalline compound having two or more, preferably two, polymerizable functional groups.
  • the polymerizable functional group an atalyloyl group, which is preferably an atalyloyl group or a methacryloyl group, is particularly preferable.
  • the liquid crystalline polyfunctional polymerizable monomer liquid crystalline diatalylate (for example, product number: RM-257, manufactured by Merck) is preferred!
  • the liquid crystalline polyfunctional polymerizable monomer bonds between the molecules of the non-liquid crystalline monofunctional polymerizable monomer to form a network structure.
  • the refractive index of the polymer obtained by polymerizing the polymerizable monomer coincide with the refractive index of the cholesteric liquid crystal because the light scattering of incident light is reduced.
  • the amount of the non-liquid crystalline monofunctional polymerizable monomer is 115% by mass based on the total amount of the cholesteric liquid crystal, the non-liquid crystalline monofunctional polymerizable monomer, and the liquid crystalline polyfunctional polymerizable monomer. It is preferably 4% by mass.
  • the amount of the liquid crystalline polyfunctional polymerizable monomer is 3 to 7% by mass based on the total amount of the cholesteric liquid crystal, the non-liquid crystalline monofunctional polymerizable monomer, and the liquid crystalline polyfunctional polymerizable monomer. It is preferably 6% by mass.
  • a cholesteric liquid crystal when used by using a non-liquid crystalline compound as a monofunctional polymerizable monomer, light due to the appearance of a focal conic state can be obtained during a voltage application process and a voltage cutoff process. The effect of preventing the occurrence of the scattering state is obtained. In order to realize this effect, it is considered that the relative ratio between the non-liquid crystalline monofunctional polymerizable monomer and the liquid crystalline polyfunctional polymerizable monomer is important. It is preferable that the polymerizable monomer is contained more than the non-liquid crystalline monofunctional polymerizable monomer. Specifically, it is preferable to use a liquid crystal polyfunctional polymerizable monomer in an amount of 112 times by mass the non-liquid crystal monofunctional polymerizable monomer.
  • a polymer-stabilized cholesteric liquid crystal can be obtained by sandwiching the liquid crystal composition between the pair of opposed substrates and irradiating ultraviolet rays to perform a polymerization reaction.
  • the intensity of the ultraviolet light and the polymerization temperature can be appropriately set.
  • the polymerization reaction is effective
  • the amount of the polymerization initiator is preferably 0.01 to 1% by mass based on the liquid crystal composition. Particularly preferred is 0.05-0.5% by mass.
  • the liquid crystal used in the liquid crystal layer is obtained by polymerizing a liquid crystal composition containing a liquid crystal exhibiting a cholesteric blue phase and a polymerizable monomer, and the cholesteric blue phase appears due to networking of the polymer. You may use a polymer-stabilized cholesteric blue phase liquid crystal with an extended temperature range! ,.
  • An anti-reflection film may be formed on the surface of the liquid crystal light modulation element of the present invention, if necessary, for the purpose of suppressing reflection of incident light!
  • the liquid crystal light modulation device having the above-described configuration further includes a polarization selection unit that selectively transmits linearly polarized light in a predetermined direction on the light exit surface side thereof. Is such that the selective reflection wavelength is in the vicinity of the wavelength of the incident light of the liquid crystal light modulation element, and when no voltage is applied, the optical rotation angle when the incident light is transmitted exceeds 0 ° and is less than 180 °. It is assumed that the transmittance of incident light changes according to whether voltage is applied to the electrode or not.
  • the selective reflection wavelength of the liquid crystal layer is near the wavelength of the incident light
  • the selective reflection wavelength of the liquid crystal layer and the incident light of the liquid crystal layer are sufficiently large so that the optical rotation to the incident light is exhibited in the liquid crystal. It means that the wavelength is close. Specifically, the difference between the two wavelengths is preferably less than 100 nm. However, if these two wavelengths are too close, the insertion loss due to reflection may increase. Therefore, it is preferable to adjust the selective reflection wavelength of the liquid crystal layer so that the wavelength of the incident light is separated by 5 nm or more, preferably 30 nm or more from the reflection end closer to the incident light of the selective reflection wavelength.
  • the optical rotation angle when no voltage is applied is up to a power of 20 ° to 160 °, particularly from 50 ° to 130 °, and further to an 80 ° force of 100 °, the contrast of emitted light caused by the presence or absence of an applied voltage This is preferable because it is possible to improve
  • the transmittance at the time of light attenuation can be reduced to 42% or less.
  • the transmittance at the time of light attenuation can be reduced to 3% or less.
  • it is preferable to set the optical rotation angle to 90 ° when no voltage is applied since the contrast of the emitted light generated by the presence or absence of the applied voltage can be maximized.
  • an optical attenuator having incident wavelength dependence can be realized. That is, when the incident light includes the first incident light having the first wavelength and the second incident light having the second wavelength, the liquid crystal layer has a selective reflection wavelength of the first wavelength.
  • the angle of rotation when the incident light is transmitted when no voltage is applied is more than 0 ° and less than 180 ° within the range, for the second incident light, the angle of rotation when the incident light is transmitted when no voltage is applied is substantially zero, and for the first incident light,
  • the transmittance changes depending on whether the voltage is applied to the electrode or not, and the transmittance does not substantially change for the second incident light regardless of whether the voltage is applied to the electrode or not. To do. In this way, it is possible to realize a liquid crystal light modulation element that acts as an optical attenuator due to optical rotation for the first incident light and does not act as an optical attenuator for the second incident light. it can.
  • the selective reflection wavelength of the liquid crystal layer is sufficiently smaller than the wavelength of the second incident light so that the optical rotation of the second incident light becomes substantially zero.
  • the reflection end of the liquid crystal layer on the incident light side of the selective reflection wavelength is 100 nm or more, preferably 200 nm or more / J, with respect to the wavelength of the second incident light. .
  • polarization selecting means a polarizer or a birefringent material utilizing absorption of light in a specific wavelength region obtained by dispersing a uniaxial dichroic dye or the like in a transparent film or the like is used.
  • a polarizer using the obtained diffraction, a polarizer using total reflection made of an inorganic material such as a Glan-Thompson prism, or the like can be used.
  • the liquid crystal layer When used as a phase correction element, the liquid crystal layer has a selective reflection wavelength at a wavelength shorter than the wavelength of the incident light of the liquid crystal modulation element, and the optical rotation angle of the incident light when no voltage is applied. Is substantially zero, and at least one of the electrodes is formed so as to generate an inter-substrate voltage distribution in the plane of the substrate, and changes in the liquid crystal layer according to the inter-substrate voltage distribution are generated.
  • the wavefront of the incident light By changing the wavefront of the incident light by causing it to have a refractive index To.
  • one of the electrodes formed on the pair of substrates is divided so that the applied voltage differs for each of the divided electrode portions.
  • the shape of the electrode may be selected in accordance with the shape of the wavefront to be corrected. For example, when spherical aberration is corrected, concentric circular or annular split electrodes can be used.
  • a part of the electrode is formed of a film having higher electric resistance than other parts, and a potential distribution is continuously provided in the electrode surface. You may make it do. Further, a configuration having both the electrode capable of providing such a continuous potential distribution and the above-mentioned divided electrode may be employed.
  • two or more power supply units for supplying different voltages are formed at different positions in the plane of the electrode on at least one substrate.
  • the electrodes forming two or more power supply units for supplying different voltages may be a single continuous electrode or a divided electrode obtained by dividing one electrode into a plurality of electrodes.
  • two or more power supply units for supplying different voltages to the divided electrodes are formed, two or more power supply units for supplying different voltages to all the divided electrodes may be formed.
  • Two or more power supply units for supplying different voltages to the divided electrodes of the unit may be formed.
  • the number of power supply sections varies depending on the purpose and shape. If about 10 electrodes are provided for one electrode, the wavefront can be changed by a necessary amount. [0053] The sheet resistance of the power supply part material forming the power supply part and the sheet of the electrode material other than the power supply part
  • the ratio p / ⁇ to the resistance P is preferably set to 1000 or more. / ⁇ force, in case
  • ⁇ is about 0.1—10 ⁇ , and ⁇ is 100
  • the feeding portion materials include copper, gold, aluminum, metal material such as chrome point force of conductive 'durability preferred, the electrical resistivity at room temperature 10- 8 - 10- 7 ⁇ ⁇ at about ⁇ If it is, a material other than metal may be used.
  • the shape and size of the power supply unit are corrected! /, And are changed in accordance with the wavefront aberration. That is, the change in the wavefront generated by the phase correction element depends on the shape and size of the power supply unit, and may be changed according to the type of the corrected wavefront aberration, the generated wavefront shape, and the wavefront shape.
  • the wavefront aberration includes coma, spherical aberration, astigmatism and the like.
  • each of the plurality of power supply units is arranged in a concentric annular shape.
  • the selective reflection wavelength of the liquid crystal layer is sufficiently smaller than the wavelength of the second incident light so that the optical rotation of the second incident light becomes almost zero.
  • the reflection end on the incident light side of the selective reflection wavelength of the liquid crystal layer is preferably 100 nm or more, preferably 200 nm or more smaller than the wavelength of the second incident light.
  • the voltage is too small, the voltage for driving the cholesteric liquid crystal will increase. It is preferable to do.
  • the absorption edge is at a wavelength of 300 nm or more!
  • FIG. 1 is a side sectional view conceptually showing the configuration of the liquid crystal light modulation device according to the present embodiment.
  • the liquid crystal light modulation device according to the present embodiment is realized as an optical attenuator 200.
  • the optical attenuator 200 is referred to as a liquid crystal light modulation element (optical attenuator) 200.
  • liquid crystal layer 1 of the liquid crystal light modulator (optical attenuator) 200 As a material of the liquid crystal layer 1 of the liquid crystal light modulator (optical attenuator) 200, 50.4% by mass of a nematic liquid crystal (manufactured by Chisso Corporation, product number: JC-1041XX), and a nematic liquid crystal (manufactured by Tokyo Chemical Industry Co., Ltd.) 35.6% by mass, product number: 5CB), 6.28% by mass of a right-handed chiral agent (Merck, product number: ZLI-4572) with a torsional force of about 30 [lZ wm], liquid crystal bifunctional Atarire preparative (Merck, product number: RM257) a 5.02 mass%, and non-liquid crystal monofunctional Atarire over preparative (hexyl Atari rate to 2 Echiru, Aldrich Co., Ltd.) 2.42 mass 0 / 0, the polymerization initiator (2, 2-dimethoxy-2-Hue
  • the compounding ratio of each component is the ratio of each component to the total amount of the nematic liquid crystal, the chiral agent, the liquid crystalline bifunctional acrylate, the non-liquid crystalline monofunctional acrylate, and the polymerization initiator.
  • electrodes 3 and 4 having ITO power were formed on substrates 5 and 6, and a horizontal alignment film (not shown) was further formed thereon, followed by rubbing.
  • the liquid crystal prepared as described above was placed in a cell formed by substrates 5 and 6 on which electrodes 3 and 4 and a horizontal alignment film were formed as shown in FIG. 1, and a sealing material 2 mixed with a spacer for liquid crystal. Enclose the composition to form a liquid crystal layer 1 with a die of 10 m.
  • the liquid crystal layer 1 was irradiated with ultraviolet light having a wavelength of 365 nm at 10 OmWZcm 2 to form a polymer-stabilized cholesteric liquid crystal, thereby producing a liquid crystal cell 110.
  • a polarizer 7 for selectively transmitting linearly polarized light in a predetermined direction is provided on the light emission surface side of the liquid crystal cell 110 with the polarization direction of the incident light (here, the Y-axis direction).
  • the liquid crystal light modulation device (optical attenuator) 200 was manufactured by adhesively fixing the polarization direction to the same Y-axis direction.
  • FIG. 3 is a graph showing these results.
  • the reflection end of the liquid crystal layer of the present example on the long wavelength side of the selective reflection wavelength is near 650 nm, and the transmitted light has almost an ellipticity with respect to the incident light having the wavelength of 660 nm.
  • this liquid crystal light modulation element acts as an optical attenuator with a contrast of about 3: 1 for incident light having a wavelength of 660 nm.
  • the graph shown in FIG. 3 indicates that the light is linearly polarized light having an ellipticity of almost 0, and does not exhibit optical rotation (the optical rotation angle is zero). It can be seen that the light transmitted through the polarizer is transmitted with a transmittance of about 100% when no voltage is applied. In addition, the transmittance when voltage is applied becomes 100% for the same reason as described for the incident light with a wavelength of 660 nm, and does not act as an optical attenuator for the incident light with a wavelength of 780 nm! / .
  • the liquid crystal cell 110 manufactured as this experimental element was applied to the liquid crystal cell 110 manufactured as this experimental element, and the change in the refractive index was measured at a wavelength of 750 nm. As a result, it was confirmed that the refractive index isotropically decreased by about 0.08. From this, by forming one of the electrodes 3 and 4 so as to generate a distribution of the inter-substrate voltage in the substrate surface in accordance with the wavefront aberration to be corrected, the inter-substrate voltage is formed. By changing the refractive index of the liquid crystal layer according to the distribution, the wavefront of the incident light can be changed.
  • Figure 4 shows the wavefront aberration (spherical surface) that occurs when the thickness of the optical disk is 0.03 mm thicker than the design value of 0.6 mm in an optical system with an objective lens NA of 0.65 and a light source wavelength of 0.4 m.
  • FIG. If the optical disk is thicker than the design value, the phase of the middle part sandwiched between the center of the effective pupil and the peripheral part of the effective pupil is advanced, and if the optical disk is thinner than the design value, The phase is delayed.
  • Fig. 5 shows the electrode pattern of the phase correction element in this example.
  • the hatched portions in FIG. 5 are one continuous transparent electrode 80 formed of an ITO film, and the thick line portions are metal electrodes 81 to 83 functioning as a power supply unit.
  • Each of the metal electrodes 81-83 is connected to an external signal source via a metal wiring 84, and can supply an arbitrary voltage from each of the signals 113.
  • the electrode pattern is formed as follows. First, an ITO film is formed on a glass substrate by a sputtering method, and then patterned using a photolithography technique. At this time, the portion where the metal electrodes 81-83 are formed leaves the ITO film, and the metal wiring portion connected to the metal electrodes 82 and 83 is etched around the metal wiring portion so as to be insulated from the transparent electrode 80. Remove the ITO film. Next, metal electrodes 82 and 83 and metal wiring of FIG. 5 are formed. The metal electrode material used here is aluminum.
  • the outer diameters of metal electrodes 81 and 82 in FIG. 5 are 4 mm and 3 mm, respectively, the width is 100 ⁇ m, and the diameter of metal electrode 83 is 200 ⁇ m.
  • An appropriate voltage is supplied to the metal electrodes 81, 82, and 83 in order to correct the spherical aberration generated by the thickness unevenness of the optical disk of 0.03 mm by the phase correction element.
  • the electrode facing the electrode with three power supply parts (metal electrodes) is composed of one continuous transparent electrode with one power supply part, and is always at the OV potential.
  • a voltage distribution is generated in the transparent electrode 80 according to the voltage of each metal electrode. As a result of the voltage distribution producing a substantial refractive index distribution in the liquid crystal, the phase correction element can generate concentric phase changes.
  • the liquid crystal light modulation device is a liquid crystal light modulation device using cholesteric liquid crystal, in which a light scattering state due to the appearance of a focal conic state does not occur in a voltage application process and a voltage cutoff process. It is a modulation element and can be used for optical communication or optical head devices.
  • cholesteric liquid crystal in which a light scattering state due to the appearance of a focal conic state does not occur in a voltage application process and a voltage cutoff process. It is a modulation element and can be used for optical communication or optical head devices.

Landscapes

  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Liquid Crystal (AREA)

Abstract

A liquid crystal optical modulating device in which any light scattering state due to a focal conic state is not brought about in the voltage application process and voltage cut-off process even if a cholesteric liquid crystals used. The liquid crystal optical modulating device comprises a pair of opposed substrates (5, 6), electrodes (3, 4) formed on the respective substrates (5, 6), and a liquid crystal layer (1) interposed between the substrates (5, 6) and secured by a sealing agent (2). The liquid crystal layer (1) comprises a polymer stabilized cholesteric liquid crystal formed as a composite of a low molecular weight liquid crystal forming a cholesteric phase and a photopolymerizable polymer liquid crystal. Any light scattering state due to a focal conic state can be prevented in both voltage application and cut-off states.

Description

明 細 書  Specification
液晶光変調素子  Liquid crystal light modulator
技術分野  Technical field
[0001] 本発明は、半導体レーザを用いた光学システムにおいて、光の透過率や波面の状 態などを制御する液晶光変調素子に関し、特に光通信または光ヘッド装置等に用い る液晶光変調素子に関する。  The present invention relates to a liquid crystal light modulation element for controlling light transmittance, a state of a wavefront, and the like in an optical system using a semiconductor laser, and more particularly, to a liquid crystal light modulation element used for optical communication, an optical head device, or the like. About.
背景技術  Background art
[0002] コレステリック液晶やカイラル剤が含有されたネマティック液晶は、図 2の模式図に 示すように液晶分子 10が螺旋構造のねじれ配向を有する広義のコレステリック液晶 構造となる (本明細書ではこれらを総称して単に「コレステリック液晶」と 、う）。これら のコレステリック液晶の電圧印加応答は、次のようになる。  [0002] A cholesteric liquid crystal or a nematic liquid crystal containing a chiral agent has a broadly defined cholesteric liquid crystal structure in which liquid crystal molecules 10 have a helical twisted orientation as shown in the schematic diagram of FIG. Collectively, it is simply called "cholesteric liquid crystal". The voltage application response of these cholesteric liquid crystals is as follows.
[0003] 通常のポリイミド配向膜を形成した表面では、電圧非印加時に、液晶分子はほぼ水 平方向の配向となり、螺旋軸が基板に対して垂直な方向を向くプレーナ状態となる。  [0003] On the surface on which an ordinary polyimide alignment film is formed, when no voltage is applied, the liquid crystal molecules are oriented in a substantially horizontal direction, and a helical axis is oriented in a direction perpendicular to the substrate in a planar state.
[0004] しかし、電圧を印加していくと、螺旋軸の方向が基板に対してそれぞれ異なる複数 のドメインからなり、光を強く散乱するフォーカルコニック状態が出現し、印加する電 圧をさらに高くしていくと、液晶分子が基板に対して垂直に配向するホメオト口ピック 配向の状態が出現する。一方、ホメオト口ピック配向した状態力も電圧を急激に降下 させると、プレーナ状態となるが、段階的に下げた場合はフォーカルコニック状態とな る。  [0004] However, when a voltage is applied, a helical axis is formed of a plurality of domains different from each other with respect to the substrate, and a focal conic state in which light is strongly scattered appears, and the applied voltage is further increased. As a result, a state of homeotropic pick alignment in which liquid crystal molecules are aligned perpendicular to the substrate appears. On the other hand, when the voltage of the home-orientated pick-oriented state force drops rapidly, the state changes to the planar state, but if the voltage is lowered stepwise, the state changes to the focal conic state.
[0005] コレステリック液晶を用いた素子の例としては、例えば、フォーカルコニック状態に おける光散乱特性を利用した表示素子等がある (例えば、非特許文献 1参照。 ) oま た、コレステリック相を示す低分子液晶と高分子液晶の複合系としては、例えば、フォ 一カルコニック状態における光散乱特性を用いた液晶シャッター（例えば、特許文献 [0005] As an example of an element using a cholesteric liquid crystal, for example, there is a display element utilizing light scattering characteristics in a focal conic state (for example, see Non-Patent Document 1). As a composite system of a low-molecular liquid crystal and a high-molecular liquid crystal, for example, a liquid crystal shutter using light scattering characteristics in a focal conic state (for example, see Patent Document 1)
1参照。）があるが、これはフォーカルコニック状態を安定に保持することを目的にす るものであり、フォーカルコニック状態の出現による光散乱状態を回避することを目的 としていない。 See 1. However, this is intended to maintain the focal conic state stably, but not to avoid the light scattering state due to the appearance of the focal conic state.
[0006] また、従来のコレステリック液晶を用いた液晶光変調素子の一例として、光減衰器 の構成の一例を図 1に示す。図 1に示す光減衰器 200は、電圧印加用の電極 3、 4が 形成された基板 5、 6との間に、図 2に示すような螺旋構造を有するコレステリック液晶 力 なる液晶層 1が、その螺旋軸が基板 5、 6に対して垂直方向を向くように狭持され 、シール材 2を用いて密閉されてなる液晶セル 110と、液晶セル 110の光出射面側 に、入射直線偏光の偏光方向と同じ方向の直線偏光を選択的に透過する偏光子 7 が配置された構成となっている。ここで、入射光の偏光方向は、図 1に符号 9を付して 示した。 [0006] Further, as an example of a conventional liquid crystal light modulator using a cholesteric liquid crystal, an optical attenuator is used. Fig. 1 shows an example of the configuration. The optical attenuator 200 shown in FIG. 1 has a cholesteric liquid crystal layer 1 having a helical structure as shown in FIG. 2 between a substrate 5 and a substrate 6 on which electrodes 3 and 4 for voltage application are formed. The liquid crystal cell 110, which is held so that its helical axis is perpendicular to the substrates 5 and 6 and is hermetically sealed with the sealing material 2, and the light exit surface side of the liquid crystal cell 110, In this configuration, a polarizer 7 that selectively transmits linearly polarized light in the same direction as the polarization direction is arranged. Here, the polarization direction of the incident light is indicated by reference numeral 9 in FIG.
[0007] この場合、電圧非印加時には、コレステリック液晶の旋光性により偏光子 7を透過す る光量が減衰するが、矩形波を発生する交流電源 (以下、単に、矩形波交流電源 8と いう。）から液晶セル 110に電圧を印加すると、液晶がホメオト口ピック配向になり、旋 光性がなくなるため偏光子 7を透過する光量が減衰しない。そのため、図 1に示す光 変調素子は、光減衰器として作用する。  [0007] In this case, when no voltage is applied, the amount of light passing through the polarizer 7 is attenuated due to the optical rotation of the cholesteric liquid crystal, but an AC power supply that generates a square wave (hereinafter, simply referred to as a rectangular wave AC power supply 8). When a voltage is applied to the liquid crystal cell 110 from step (1), the liquid crystal becomes homeotropically pick-aligned and loses optical rotation, so that the amount of light transmitted through the polarizer 7 does not attenuate. Therefore, the light modulation device shown in FIG. 1 acts as an optical attenuator.
[0008] また、近年、光ディスクの記録密度を高めるために、光源である半導体レーザから の出射光の波長を短くすることや、対物レンズの開口数 (以下、 NAという。）を大きく すること等が行われている。そして、次世代の光記録においては、光源の波長を 405 nm程度、 NAを 0. 85として、より大きな記録密度を得ようとしている。しかし、光源の 短波長化や対物レンズの高 NA化が原因で、光ディスクの厚み変動の許容量が小さ くなる。  [0008] In recent years, in order to increase the recording density of an optical disk, the wavelength of light emitted from a semiconductor laser as a light source is shortened, and the numerical aperture (hereinafter, referred to as NA) of an objective lens is increased. Has been done. In the next-generation optical recording, a light source having a wavelength of about 405 nm and an NA of 0.85 is intended to obtain a higher recording density. However, due to the shorter wavelength of the light source and the higher NA of the objective lens, the permissible amount of thickness variation of the optical disk is reduced.
[0009] 光ディスクの厚み変動の許容量が小さくなる理由は、光ディスクの厚み変動に比例 して、波面収差の一つである球面収差が発生するために、光ヘッド装置の集光特性 が劣化して信号の読み取りが困難になるからである。  [0009] The reason that the allowable amount of variation in the thickness of the optical disc is reduced is that the spherical aberration, which is one of the wavefront aberrations, occurs in proportion to the variation in the thickness of the optical disc, and the light-collecting characteristics of the optical head device deteriorate. This makes it difficult to read signals.
[0010] また、光ディスクを構成する各層の相異なる層をそれぞれ記録層とする多層記録方 式の場合でも、記録層の位置に対応した球面収差が発生するためそれを補正する 手段が必要である。  [0010] Also, even in the case of a multilayer recording method in which different layers of each layer constituting an optical disc are used as recording layers, spherical aberration corresponding to the position of the recording layer is generated, so that means for correcting the spherical aberration is required. .
[0011] 球面収差を補正する手段として、以下の方式が提案されている。第 1の方式として、 発生した球面収差の量に応じてコリメートレンズの位置を機械的に変化させ、コリメ一 トレンズと対物レンズとの間で球面収差を発生させ、光ディスクの厚み誤差で発生す る球面収差を打ち消す方式 (以下、機械方式という。）がある。機械方式の場合、コリ メートレンズを機械的に動かす可動部分 (以下、機械可動部分という。）を必要とする ため、光ヘッド装置の構成が複雑または大きくなる欠点がある。 The following methods have been proposed as means for correcting spherical aberration. The first method is to mechanically change the position of the collimating lens in accordance with the amount of generated spherical aberration, to generate spherical aberration between the collimating lens and the objective lens, and to generate the optical disk thickness error. There is a method for canceling spherical aberration (hereinafter referred to as a mechanical method). In the case of mechanical method, Since a movable part for mechanically moving the mate lens (hereinafter referred to as a mechanical movable part) is required, there is a disadvantage that the configuration of the optical head device becomes complicated or large.
[0012] 第 2の方式として、対物レンズと光源との間の光路中に電気的に駆動可能な位相 補正素子を設けることにより、波面収差を補正する方式 (以下、電気方式という。）が ある。この電気方式の場合、機械方式に比べると、機械可動部分がないことから、小 型軽量化や振動に対する信頼性にお！、て優れて!/ヽる。  As a second method, there is a method for correcting wavefront aberration by providing an electrically drivable phase correction element in an optical path between an objective lens and a light source (hereinafter, referred to as an electric method). . Compared to the mechanical system, this electric system has no mechanical moving parts, so it is small and lightweight and has high reliability against vibration! Excellent!
[0013] 液晶光変調素子を位相補正素子として用いて波面収差を補正する技術もある (例 えば、特許文献 2参照。 ) 0この技術では、光ディスクの傾きにより発生する、波面収 差の一つであるコマ収差を、以下のようにして補正している。すなわち、液晶光変調 素子を構成する一対の基板間に挟持された液晶の配向を、分割電極に印加する電 圧を変化させて制御し、これにより透過光の波面を変化させ、発生するコマ収差を補 正している。 [0013] There is also a technique for correcting wavefront aberration using a liquid crystal light modulation element as a phase correction element (for example, see Patent Document 2). 0 In this technique, one of the wavefront differences generated due to the tilt of the optical disc is considered. Is corrected in the following manner. That is, the orientation of the liquid crystal sandwiched between a pair of substrates constituting the liquid crystal light modulation element is controlled by changing the voltage applied to the divided electrodes, thereby changing the wavefront of the transmitted light and generating the coma aberration. Has been corrected.
[0014] 特許文献 1：特開平 4 260024号公報  Patent Document 1: Japanese Patent Application Laid-Open No. Hei 4 260024
特許文献 2：特開平 10- 20263号公報  Patent Document 2: JP-A-10-20263
非特許文献 1 :液晶便覧編集委員会編、「液晶便覧第 5章」、丸善株式会社、平成 12 年  Non-patent Document 1: Liquid Crystal Handbook Editing Committee, `` LCD Handbook Chapter 5 '', Maruzen Co., Ltd., 2000
発明の開示  Disclosure of the invention
発明が解決しょうとする課題  Problems to be solved by the invention
[0015] しかし、このような従来のコレステリック液晶を用いた液晶光変調素子では、電圧印 加過程および電圧遮断過程でフォーカルコニック状態が生じ、光散乱状態が発生す るため、半導体レーザを用いた光学システムへの用途が制限されるという問題があつ た。 However, in such a conventional liquid crystal light modulation device using a cholesteric liquid crystal, a focal conic state occurs during a voltage application process and a voltage cutoff process, and a light scattering state occurs. There was a problem that the application to optical systems was limited.
[0016] また、従来の液晶光変調素子を光減衰器として用いた場合、電圧印加過程および 電圧遮断過程でフォーカルコニック状態が生じ、光散乱状態が発生するため、印加 電圧の大きさに応じて透過光量を連続的に制御することが困難である問題があった  When a conventional liquid crystal light modulation element is used as an optical attenuator, a focal conic state occurs during a voltage application process and a voltage cutoff process, and a light scattering state occurs. There was a problem that it was difficult to continuously control the amount of transmitted light
[0017] また、特許文献 2に開示されて ヽる位相補正素子では、ネマティック液晶またはツイ ステツドネマティック (TN)液晶が用いられて ヽるため、入射光の偏光方向に位相が 依存する偏光状態依存性が生じる。しかし、光源の波長が短ぐ 405nm程度になる と、光源力 の出射光の波面収差を補正するだけでは充分ではなぐ光記録媒体に より反射された光の波面収差も補正する必要が生じる。そのためには液晶光変調素 子の偏光状態依存性を除去または低減する必要がある。偏光状態依存性を除去ま たは低減する方法としては、位相補正素子を 2層にするなどの方法が考えられるが、 素子構成が複雑になるという問題があった。 [0017] In the phase correction element disclosed in Patent Document 2, a nematic liquid crystal or a twisted nematic (TN) liquid crystal is used, so that the phase in the polarization direction of the incident light is changed. Dependent polarization state dependence occurs. However, when the wavelength of the light source is short, about 405 nm, it is not sufficient to correct the wavefront aberration of the light emitted from the light source, and it is necessary to correct the wavefront aberration of the light reflected by the optical recording medium. For that purpose, it is necessary to remove or reduce the polarization state dependence of the liquid crystal light modulation element. As a method of removing or reducing the polarization state dependency, a method of using two layers of phase correction elements is conceivable, but there is a problem that the element configuration becomes complicated.
[0018] 本発明はこのような問題を解決するためになされたもので、コレステリック液晶を用 いる液晶光変調素子において、電圧印加過程および電圧遮断過程で、フォーカルコ ニック状態の出現による光散乱状態が発生しない液晶光変調素子を提供する。 課題を解決するための手段 The present invention has been made to solve such a problem. In a liquid crystal light modulation element using a cholesteric liquid crystal, a light scattering state caused by the appearance of a focal conic state in a voltage application process and a voltage cutoff process. Provided is a liquid crystal light modulation element in which no light is generated. Means for solving the problem
[0019] 本発明は以下の要旨を有する。 [0019] The present invention has the following gist.
1.対向して配置された一対の基板、前記それぞれの基板の相対向する表面に形成 された電極、および前記一対の基板間に狭持された液晶層を備え、所定の波長の入 射光に対して変調を行う液晶光変調素子であって、前記液晶層は、コレステリック液 晶と、非液晶性単官能重合性モノマーと、液晶性多官能重合性モノマーとを含む液 晶組成物を重合させてなる高分子安定ィ匕コレステリック液晶からなり、電圧印加過程 および電圧遮断過程のいずれでもフォーカルコニック状態の出現による光散乱状態 が発生しな 、ことを特徴とする液晶光変調素子。  1. It comprises a pair of substrates arranged opposite to each other, electrodes formed on opposing surfaces of the respective substrates, and a liquid crystal layer sandwiched between the pair of substrates. A liquid crystal light modulation device that performs modulation on the liquid crystal layer, wherein the liquid crystal layer is formed by polymerizing a liquid crystal composition containing a cholesteric liquid crystal, a non-liquid crystal monofunctional polymerizable monomer, and a liquid crystal polyfunctional polymerizable monomer. A liquid crystal light modulation element comprising a polymer stable cholesteric liquid crystal, wherein a light scattering state does not occur due to the appearance of a focal conic state in both a voltage application process and a voltage cutoff process.
この構成により、コレステリック液晶を用いる液晶光変調素子において、電圧印加過 程および電圧遮断過程で、フォーカルコニック状態の出現による光散乱状態が発生 しな ヽ液晶光変調素子を実現できる。  With this configuration, in the liquid crystal light modulation device using the cholesteric liquid crystal, a liquid crystal light modulation device can be realized in which the light scattering state due to the appearance of the focal conic state does not occur during the voltage application process and the voltage cutoff process.
2.前記高分子安定化コレステリック液晶が、前記液晶組成物中のコレステリック液晶 と、非液晶性単官能重合性モノマーと、液晶性多官能重合性モノマーとの総量に対 して、非液晶性単官能重合性モノマーを 1一 5質量％含み、かつ、液晶性多官能重 合性モノマーを 3— 7質量％含む液晶組成物を重合させてなる高分子安定ィ匕コレス テリック液晶である、上記 1に記載の液晶光変調素子。  2. The polymer-stabilized cholesteric liquid crystal is compared with the non-liquid crystal monomer in the total amount of the cholesteric liquid crystal, the non-liquid crystal monofunctional polymerizable monomer, and the liquid crystal polyfunctional polymerizable monomer in the liquid crystal composition. The polymer-stabilized cholesteric liquid crystal obtained by polymerizing a liquid crystal composition containing 115% by mass of a functional polymerizable monomer and 3 to 7% by mass of a liquid crystalline polyfunctional polymerizable monomer. 3. The liquid crystal light modulation device according to item 1.
この構成により、電圧印加過程および電圧遮断過程で、フォーカルコニック状態の 出現による光散乱状態の発生を阻止する効果が安定して確実に、すなわち再現性よ く発現できる。 With this configuration, the effect of preventing the occurrence of the light scattering state due to the appearance of the focal conic state in the voltage application process and the voltage cutoff process is stable and reliable, that is, the reproducibility is improved. Can be expressed.
3.前記液晶光変調素子は、さらに、所定の方向の直線偏光を選択的に透過する偏 光選択手段をその光出射面側に備え、前記液晶層は、その選択反射波長が前記液 晶光変調素子の入射光の波長近傍にあって、電圧非印加時における、前記入射光 が透過する際の旋光角度が 0° を超えて 180° 未満の範囲内にあり、電極への電圧 の印加、非印加の別に応じて入射光の透過率が変化する、上記 1または 2の液晶光 変調素子。  3. The liquid crystal light modulating element further comprises a polarization selecting means for selectively transmitting linearly polarized light in a predetermined direction on a light exit surface side thereof, and the liquid crystal layer has a selective reflection wavelength of the liquid crystal light modulating light. In the vicinity of the wavelength of the incident light of the element, when no voltage is applied, the angle of optical rotation when the incident light is transmitted is within a range of more than 0 ° and less than 180 °, and the application of voltage to the electrode and the The liquid crystal light modulation device of the above 1 or 2, wherein the transmittance of the incident light changes depending on the application.
この構成により、上記 1または 2の効果に加え、印加電圧の大きさに応じて旋光角度 を変化させることができるため、透過光量を制御できる液晶光変調素子を実現できる 。特にこの構成によれば、印加電圧を連続的に変化することにより、透過光量を連続 的〖こ変ィ匕させることができる。  With this configuration, in addition to the above-described effects 1 and 2, the optical rotation angle can be changed in accordance with the magnitude of the applied voltage, so that a liquid crystal light modulation element that can control the amount of transmitted light can be realized. In particular, according to this configuration, the amount of transmitted light can be continuously changed by continuously changing the applied voltage.
4.前記液晶層は、その選択反射波長が、前記液晶変調素子の入射光の波長より短 い波長にあって、電圧非印加時の前記入射光が透過する際の旋光角度が実質的に ゼロとなっており、前記電極のうちの少なくとも一方の電極は、基板面内で基板間電 圧の分布を生じるように形成されており、前記基板間電圧の分布に応じた変化を液 晶層の屈折率に生じさせることによって前記入射光の波面を変化させる、上記 1また は 2の液晶光変調素子。  4. In the liquid crystal layer, the selective reflection wavelength is shorter than the wavelength of the incident light of the liquid crystal modulation element, and the optical rotation angle when the incident light is transmitted when no voltage is applied is substantially zero. At least one of the electrodes is formed so as to generate an inter-substrate voltage distribution in the substrate plane, and changes in the liquid crystal layer according to the inter-substrate voltage distribution. The liquid crystal light modulation device according to the above 1 or 2, wherein the wavefront of the incident light is changed by causing a refractive index to occur.
この構成により、上記 1または 2の効果に加え、印加電圧の大きさに応じて液晶層の 屈折率を変化させることにより位相を変化させ、波面収差を補正できる液晶光変調素 子を偏光状態依存性なしで実現できる。  With this configuration, in addition to the above-mentioned effects 1 and 2, the liquid crystal light modulator that can correct the wavefront aberration by changing the phase by changing the refractive index of the liquid crystal layer according to the magnitude of the applied voltage depends on the polarization state. Can be realized without gender.
発明の効果  The invention's effect
[0020] 本発明によれば、コレステリック液晶を用いる液晶変調素子において、電圧印加過 程および電圧遮断過程で、フォーカルコニック状態の出現による光散乱状態が発生 しな 、液晶光変調素子を提供できる。  According to the present invention, it is possible to provide a liquid crystal modulation element using a cholesteric liquid crystal, in which a light scattering state due to the appearance of a focal conic state does not occur in a voltage application process and a voltage cutoff process.
図面の簡単な説明  Brief Description of Drawings
[0021] [図 1]本発明の実施例に係る液晶光変調素子 (光減衰器)の構成の一例を示す側面 図であると共に、従来の液晶光変調素子 (光減衰器)の構成の一例を示す側面図。  FIG. 1 is a side view showing an example of a configuration of a liquid crystal light modulation element (optical attenuator) according to an embodiment of the present invention, and an example of a configuration of a conventional liquid crystal light modulation element (optical attenuator). FIG.
[図 2]コレステリック液晶の分子配列を概念的に示す図。 [図 3]実験用液晶セルの旋光角度、楕円率、および、透過率の波長依存性を示す測 定結果のグラフ。 FIG. 2 is a diagram conceptually showing a molecular arrangement of a cholesteric liquid crystal. FIG. 3 is a graph of measurement results showing the wavelength dependence of the optical rotation angle, ellipticity, and transmittance of the experimental liquid crystal cell.
[図 4]光ディスクに厚みむら 0. 03mmが発生したときの球面収差を示す概念図。  FIG. 4 is a conceptual diagram showing spherical aberration when 0.03 mm of thickness unevenness occurs on an optical disc.
[図 5]本発明の実施例に係る液晶光変調素子 (位相補正素子)の電極パターンを示 す模式図。  FIG. 5 is a schematic view showing an electrode pattern of a liquid crystal light modulation element (phase correction element) according to an example of the present invention.
符号の説明  Explanation of symbols
[0022] 1 液晶層 [0022] 1 liquid crystal layer
2 シール材  2 Sealing material
3、 4 電極  3, 4 electrodes
5、 6 基板  5, 6 substrate
7 偏光子  7 Polarizer
8 矩形波交流電源  8 Square wave AC power supply
9 直線偏光で入射する光の偏光方向  9 Polarization direction of incident light with linear polarization
110 液晶セル  110 liquid crystal cell
200 液晶光変調素子 (光減衰器）  200 Liquid crystal light modulator (optical attenuator)
発明を実施するための最良の形態  BEST MODE FOR CARRYING OUT THE INVENTION
[0023] 以下、本発明の実施の形態について、具体的に説明する。 Hereinafter, embodiments of the present invention will be specifically described.
本発明の実施の形態に係る液晶光変調素子は、半導体レーザ等の光源を用いた 光システム系において用いられ、一対の対向する基板と、各基板の相対向する表面 に形成された電極と、上記の一対の対向する基板間に狭持された液晶層とを備えた 構成を有する。  The liquid crystal light modulation device according to the embodiment of the present invention is used in an optical system using a light source such as a semiconductor laser, and includes a pair of opposed substrates, and electrodes formed on opposed surfaces of each substrate, And a liquid crystal layer sandwiched between the pair of opposing substrates.
[0024] 液晶光変調素子を構成する基板として、例えば、アクリル系榭脂、エポキシ系榭脂 、塩ィ匕ビュル系榭脂、ポリカーボネート等を用いてもよいが、耐久性等の点力もガラス 基板が好適である。一対の基板間に挟持される液晶層に所定の厚さを保持させるた めに、ガラスファイバやプラスチックビーズなどの公知のスぺーサを基板間に介在さ せる。  As a substrate constituting the liquid crystal light modulation element, for example, an acrylic resin, an epoxy resin, a salt-based butyl resin, or a polycarbonate may be used. Is preferred. A known spacer such as a glass fiber or a plastic bead is interposed between the substrates in order to maintain a predetermined thickness in the liquid crystal layer sandwiched between the pair of substrates.
[0025] また、液晶層を狭持する基板表面には水平配向膜を成膜すると、コレステリック液 晶の螺旋軸が基板に対して垂直な方向を向いたプレーナ状態を容易に実現できる ため、好適である。該配向膜の材料としては、ポリイミド等を使用できる。更に、水平 配向膜にラビング処理を施し、基板界面近傍の液晶分子を一様に配向させるよう〖こ することも好適である。 When a horizontal alignment film is formed on the surface of the substrate sandwiching the liquid crystal layer, a planar state in which the helical axis of the cholesteric liquid crystal is oriented in a direction perpendicular to the substrate can be easily realized. Therefore, it is suitable. Polyimide or the like can be used as a material for the alignment film. Further, it is also preferable to perform a rubbing treatment on the horizontal alignment film so as to uniformly align the liquid crystal molecules near the substrate interface.
[0026] 電極としては、酸化インジウムスズ (ITO)等からなる酸化物膜や、 Au、 A1等力もな る金属膜を用いることができるが、 ITO膜を用いる方が金属膜に比べ、光の透過性が よぐ機械的耐久性が優れているため、好適である。  [0026] As the electrode, an oxide film made of indium tin oxide (ITO) or a metal film having a strong force such as Au or A1 can be used. It is suitable because it has good permeability and good mechanical durability.
[0027] 上記の液晶層は、コレステリック液晶と、非液晶性単官能重合性モノマーと、液晶 性多官能重合性モノマーとを含む液晶組成物を重合させてなる高分子安定化コレス テリック液晶からなる層である。液晶層をこのように構成することにより、電圧印加過程 と電圧遮断過程の 、ずれにぉ 、ても、フォーカルコニック状態が生ずることによる光 散乱状態を示さな 、ようにできる。  The liquid crystal layer is composed of a polymer stabilized cholesteric liquid crystal obtained by polymerizing a liquid crystal composition including a cholesteric liquid crystal, a non-liquid crystal monofunctional polymerizable monomer, and a liquid crystal polyfunctional polymerizable monomer. Layer. By configuring the liquid crystal layer in this manner, even if there is a difference between the voltage application process and the voltage cutoff process, the light scattering state due to the occurrence of the focal conic state can be prevented.
[0028] 上記の液晶層を得るために用いられるコレステリック液晶としては、コレステリック液 晶ゃカイラル剤が含有されたネマティック液晶（カイラルネマティック液晶）を用いるこ とができる。後者においては、カイラル剤の濃度を調節することにより選択的に反射 する光の波長 (以下、「選択反射波長」という。）を調節できる。後者におけるネマテイツ ク液晶としては、液晶表示装置に用いられる市販のネマティック液晶等でよい。たとえ ば、ベンゼン環、シクロへキサン環を 2— 4個含んだ構造を有するネマティック液晶が 挙げられる。該液晶は置換基としてフッ素原子、シァノ基等を有することが好ましい。  As the cholesteric liquid crystal used to obtain the above liquid crystal layer, a nematic liquid crystal (chiral nematic liquid crystal) containing a cholesteric liquid crystal / chiral agent can be used. In the latter, by adjusting the concentration of the chiral agent, the wavelength of light that is selectively reflected (hereinafter, referred to as “selective reflection wavelength”) can be adjusted. As the nematic liquid crystal in the latter, a commercially available nematic liquid crystal used for a liquid crystal display device may be used. For example, a nematic liquid crystal having a structure containing 2 to 4 benzene rings and cyclohexane rings is exemplified. The liquid crystal preferably has a substituent such as a fluorine atom or a cyano group.
[0029] カイラル剤は、不斉炭素を有する光学活性物質でよぐ必ずしも液晶性を示す必要 はないが、ネマティック液晶との相溶性がよぐねじり力（Helical Twist Power :H TP)の高 ヽ材料が望ま ヽ。ここで、ねじり力（HTP)と螺旋ピッチ（P)とカイラル剤濃 度 (C)との間には、 HTP= lZ (P'C)の関係があり、ねじり力が大きい程、少量の力 ィラル剤で螺旋ピッチを小さくすることができる。また、複数のカイラル剤を混合して螺 旋ピッチの温度依存性を少なくしたものでもよい。  A chiral agent is an optically active substance having an asymmetric carbon and does not necessarily have to exhibit liquid crystallinity, but has high compatibility with a nematic liquid crystal and a high twisting power (HTP). Material is desirable ヽ. Here, there is a relationship of HTP = lZ (P'C) between the torsional force (HTP), the helical pitch (P), and the chiral agent concentration (C). The spiral pitch can be reduced by using a spiral agent. Further, a mixture of a plurality of chiral agents may be used to reduce the temperature dependence of the helical pitch.
[0030] さらに、電圧駆動の光変調素子の場合は、誘電率異方性の大きい方が低い電圧で 駆動できるため望ましぐそのためには、末端基としてフッ素原子やシァノ基等を含む ものが望ましい。  [0030] Further, in the case of a voltage-driven light modulation element, a substance having a large dielectric anisotropy can be driven at a low voltage. desirable.
[0031] 上記の液晶層を得るために用いられる非液晶性単官能重合性モノマーとは、 1個 の重合性官能基を有する非液晶性の化合物である。該モノマーとしては、アタリロイ ル基またはメタクリロイル基 (好ましくはアタリロイル基)を 1個有する化合物であること が好ましぐなかでも、非液晶性アクリル酸エステル類、非液晶性メタクリル酸エステ ル類が好ましぐ非液晶性アクリル酸エステル類が特に好まし ヽ。 [0031] The non-liquid crystalline monofunctional polymerizable monomer used to obtain the above liquid crystal layer includes one Is a non-liquid crystalline compound having a polymerizable functional group. The monomer is preferably a compound having one atalyloyl group or methacryloyl group (preferably atariloyl group), but non-liquid crystalline acrylates and non-liquid crystalline methacrylates are preferred. Non-liquid crystalline acrylates are particularly preferred.
[0032] また、液晶性多官能重合性モノマーとしては、 2個以上、好ましくは 2個の重合性官 能基を有する液晶性の化合物である。重合性官能基としては、アタリロイル基または メタクリロイル基が好ましぐアタリロイル基が特に好ましい。液晶性多官能重合性モノ マーとしては液晶性ジアタリレート (たとえば、 Merck社製、商品番号: RM— 257)等 が好まし!/、。液晶性多官能重合性モノマーは非液晶性単官能重合性モノマーの分 子間を結合して網目構造を形成する。  [0032] The liquid crystalline polyfunctional polymerizable monomer is a liquid crystalline compound having two or more, preferably two, polymerizable functional groups. As the polymerizable functional group, an atalyloyl group, which is preferably an atalyloyl group or a methacryloyl group, is particularly preferable. As the liquid crystalline polyfunctional polymerizable monomer, liquid crystalline diatalylate (for example, product number: RM-257, manufactured by Merck) is preferred! The liquid crystalline polyfunctional polymerizable monomer bonds between the molecules of the non-liquid crystalline monofunctional polymerizable monomer to form a network structure.
[0033] また、上記重合性モノマーを重合して得られる重合体の屈折率は、コレステリック液 晶の屈折率と一致している方が入射光の光散乱が低減されるため好適である。  Further, it is preferable that the refractive index of the polymer obtained by polymerizing the polymerizable monomer coincide with the refractive index of the cholesteric liquid crystal because the light scattering of incident light is reduced.
[0034] 非液晶性単官能重合性モノマーの量は、コレステリック液晶、非液晶性単官能重合 性モノマー、および液晶性多官能重合性モノマーの総量に対して 1一 5質量％であり 、 2— 4質量％であることが好ましい。また、液晶性多官能重合性モノマーの量は、コ レステリック液晶、非液晶性単官能重合性モノマー、および液晶性多官能重合性モ ノマーの総量に対して 3— 7質量％であり、 4一 6質量％であることが好ましい。  [0034] The amount of the non-liquid crystalline monofunctional polymerizable monomer is 115% by mass based on the total amount of the cholesteric liquid crystal, the non-liquid crystalline monofunctional polymerizable monomer, and the liquid crystalline polyfunctional polymerizable monomer. It is preferably 4% by mass. The amount of the liquid crystalline polyfunctional polymerizable monomer is 3 to 7% by mass based on the total amount of the cholesteric liquid crystal, the non-liquid crystalline monofunctional polymerizable monomer, and the liquid crystalline polyfunctional polymerizable monomer. It is preferably 6% by mass.
[0035] 本発明にお 、ては、単官能重合性モノマーとして非液晶性の化合物を用いること によって、コレステリック液晶を用いる場合において、電圧印加過程および電圧遮断 過程で、フォーカルコニック状態の出現による光散乱状態の発生を阻止する効果が 得られる。また、この効果の発現のためには、非液晶性単官能重合性モノマーと液晶 性多官能重合性モノマーとの相対的な割合が重要であると考えられ、液晶組成物は 、液晶性多官能重合性モノマーを非液晶性単官能重合性モノマーに対してより多く 含むことが好ましい。具体的には、非液晶性単官能重合性モノマーに対し、液晶性 多官能重合性モノマーを 1一 2質量倍使用することが好ましい。  In the present invention, when a cholesteric liquid crystal is used by using a non-liquid crystalline compound as a monofunctional polymerizable monomer, light due to the appearance of a focal conic state can be obtained during a voltage application process and a voltage cutoff process. The effect of preventing the occurrence of the scattering state is obtained. In order to realize this effect, it is considered that the relative ratio between the non-liquid crystalline monofunctional polymerizable monomer and the liquid crystalline polyfunctional polymerizable monomer is important. It is preferable that the polymerizable monomer is contained more than the non-liquid crystalline monofunctional polymerizable monomer. Specifically, it is preferable to use a liquid crystal polyfunctional polymerizable monomer in an amount of 112 times by mass the non-liquid crystal monofunctional polymerizable monomer.
[0036] 本発明においては、前記の一対の対向する基板間前記液晶組成物を挟持した後 、紫外線を照射して重合反応を行うことによって高分子安定ィ匕コレステリック液晶を得 ることができる。紫外線の強度や重合温度は適宜設定されうる。なお、重合反応を効 率よく行うためには、前記液晶組成物中に重合開始剤を含ませることが好ましぐこの 場合の重合開始剤の量は、液晶組成物に対して 0. 01— 1質量％が好ましぐ 0. 05 一 0. 5質量％が特に好ましい。 In the present invention, a polymer-stabilized cholesteric liquid crystal can be obtained by sandwiching the liquid crystal composition between the pair of opposed substrates and irradiating ultraviolet rays to perform a polymerization reaction. The intensity of the ultraviolet light and the polymerization temperature can be appropriately set. The polymerization reaction is effective In order to perform the reaction efficiently, it is preferable to include a polymerization initiator in the liquid crystal composition. In this case, the amount of the polymerization initiator is preferably 0.01 to 1% by mass based on the liquid crystal composition. Particularly preferred is 0.05-0.5% by mass.
[0037] また、上記の液晶層に使用する液晶として、コレステリックブルー相を発現する液晶 と重合性モノマーとを含む液晶組成物を重合させてなり、高分子のネットワーク化に よりコレステリックブルー相が出現する温度範囲が拡大された高分子安定ィ匕コレステ リックブルー相液晶を用いてもよ！、。  The liquid crystal used in the liquid crystal layer is obtained by polymerizing a liquid crystal composition containing a liquid crystal exhibiting a cholesteric blue phase and a polymerizable monomer, and the cholesteric blue phase appears due to networking of the polymer. You may use a polymer-stabilized cholesteric blue phase liquid crystal with an extended temperature range! ,.
[0038] 本発明の液晶光変調素子の表面には、入射光の反射を抑制する目的で、必要に 応じて反射防止膜を形成してもよ!/ヽ。  [0038] An anti-reflection film may be formed on the surface of the liquid crystal light modulation element of the present invention, if necessary, for the purpose of suppressing reflection of incident light!
[0039] 光減衰器として用いる場合は、上記の構成の液晶光変調素子に、さらに、所定の 方向の直線偏光を選択的に透過する偏光選択手段をその光出射面側に備え、前記 液晶層は、その選択反射波長が前記液晶光変調素子の入射光の波長近傍にあって 、電圧非印加時における、前記入射光が透過する際の旋光角度が 0° を超えて 180 ° 未満の範囲内にあり、電極への電圧の印加、非印加の別に応じて入射光の透過 率が変化するものとする。  When used as an optical attenuator, the liquid crystal light modulation device having the above-described configuration further includes a polarization selection unit that selectively transmits linearly polarized light in a predetermined direction on the light exit surface side thereof. Is such that the selective reflection wavelength is in the vicinity of the wavelength of the incident light of the liquid crystal light modulation element, and when no voltage is applied, the optical rotation angle when the incident light is transmitted exceeds 0 ° and is less than 180 °. It is assumed that the transmittance of incident light changes according to whether voltage is applied to the electrode or not.
[0040] このように構成することにより、印加電圧の大きさに応じて入射光の旋光角度を変化 させることができ、出射光量を変化させることができる液晶光変調素子を実現できる。  With this configuration, it is possible to change the optical rotation angle of the incident light according to the magnitude of the applied voltage, and to realize a liquid crystal light modulation element that can change the amount of emitted light.
[0041] この場合、「液晶層の選択反射波長が入射光の波長近傍にある」とは、入射光に対 する旋光性が液晶に発現する程度に、液晶層の選択反射波長と入射光の波長とが 近接していることを言う。具体的には両者の波長の差が lOOnm以下であることが好 ましい。ただし、これら 2つの波長が近すぎる場合は、反射による挿入損失が増大す ることがある。したがって、選択反射波長の入射光に近いほうの反射端から 5nm以上 ，好ましくは 30nm以上入射光の波長が離れるように液晶層の選択反射波長を調整 することが好ましい。  In this case, “the selective reflection wavelength of the liquid crystal layer is near the wavelength of the incident light” means that the selective reflection wavelength of the liquid crystal layer and the incident light of the liquid crystal layer are sufficiently large so that the optical rotation to the incident light is exhibited in the liquid crystal. It means that the wavelength is close. Specifically, the difference between the two wavelengths is preferably less than 100 nm. However, if these two wavelengths are too close, the insertion loss due to reflection may increase. Therefore, it is preferable to adjust the selective reflection wavelength of the liquid crystal layer so that the wavelength of the incident light is separated by 5 nm or more, preferably 30 nm or more from the reflection end closer to the incident light of the selective reflection wavelength.
[0042] また、電圧非印加時の旋光角度を 20° 力 160° まで、特に 50° から 130° まで 、さらには 80° 力 100° までにすると、印加電圧の有無によって生じる出射光のコ ントラストを向上することができるため、好ましい。電圧非印加時の旋光角度を 80° か ら 100° までにすると、光減衰時の透過率を 42%以下にすることができ、電圧非印 加時の旋光角度を 50° 力も 130° までにすると、光減衰時の透過率を 3%以下にす ることができる。とりわけ、電圧非印加時の旋光角度を 90° にすると、印加電圧の有 無によって生じる出射光のコントラストを最大にできるため、好適である。 [0042] When the optical rotation angle when no voltage is applied is up to a power of 20 ° to 160 °, particularly from 50 ° to 130 °, and further to an 80 ° force of 100 °, the contrast of emitted light caused by the presence or absence of an applied voltage This is preferable because it is possible to improve By setting the optical rotation angle when no voltage is applied from 80 ° to 100 °, the transmittance at the time of light attenuation can be reduced to 42% or less. By setting the optical rotation angle at the time of addition to 50 ° and the force to 130 °, the transmittance at the time of light attenuation can be reduced to 3% or less. In particular, it is preferable to set the optical rotation angle to 90 ° when no voltage is applied, since the contrast of the emitted light generated by the presence or absence of the applied voltage can be maximized.
[0043] また、電圧非印加時における入射光の旋光角度が、入射光の波長により異なること を利用して、入射波長依存性を有する光減衰器を実現することもできる。すなわち、 入射光には第 1の波長を有する第 1の入射光と第 2の波長を有する第 2の入射光とが ある場合に、前記液晶層は、その選択反射波長が前記第 1の波長近傍であって前記 第 2の波長より短い波長にあり、第 1の入射光に対しては、電圧非印加時における前 記入射光が透過する際の旋光角度が 0° を超えて 180° 未満の範囲内にあり、第 2 の入射光に対しては、電圧非印加時における前記入射光が透過する際の旋光角度 が実質的にゼロとなるようにして、第 1の入射光に対しては電極への電圧の印カロ、非 印加の別に応じて透過率が変化し、第 2の入射光に対しては、電極への電圧の印加 、非印加にかかわらず透過率が実質的に変化しないようにする。このようにして、第 1 の入射光に対しては旋光性に起因した光減衰器として作用し、第 2の入射光に対し ては光減衰器として作用しない液晶光変調素子を実現することができる。  Also, by utilizing the fact that the angle of rotation of incident light when no voltage is applied varies depending on the wavelength of the incident light, an optical attenuator having incident wavelength dependence can be realized. That is, when the incident light includes the first incident light having the first wavelength and the second incident light having the second wavelength, the liquid crystal layer has a selective reflection wavelength of the first wavelength. Near and at a wavelength shorter than the second wavelength, and for the first incident light, the angle of rotation when the incident light is transmitted when no voltage is applied is more than 0 ° and less than 180 ° Within the range, for the second incident light, the angle of rotation when the incident light is transmitted when no voltage is applied is substantially zero, and for the first incident light, The transmittance changes depending on whether the voltage is applied to the electrode or not, and the transmittance does not substantially change for the second incident light regardless of whether the voltage is applied to the electrode or not. To do. In this way, it is possible to realize a liquid crystal light modulation element that acts as an optical attenuator due to optical rotation for the first incident light and does not act as an optical attenuator for the second incident light. it can.
[0044] この場合、液晶層の選択反射波長は、第 2の入射光の旋光性が実質的に 0になる ように第 2の入射光の波長に対して充分に小さい方がよい。具体的には、液晶層の 選択反射波長の入射光側の反射端は、第 2の入射光の波長に対して lOOnm以上、 好ましくは 200nm以上/ J、さ!/ヽほう力 ^よ!ヽ。  In this case, it is preferable that the selective reflection wavelength of the liquid crystal layer is sufficiently smaller than the wavelength of the second incident light so that the optical rotation of the second incident light becomes substantially zero. Specifically, the reflection end of the liquid crystal layer on the incident light side of the selective reflection wavelength is 100 nm or more, preferably 200 nm or more / J, with respect to the wavelength of the second incident light. .
[0045] また、上記の偏光選択手段として、一軸性の二色性色素等を透明フィルム等に分 散させて得られる特定波長領域の光の吸収を利用した偏光子、複屈折材料を用い て得られる回折を利用した偏光子、または、グラントムソンプリズム等の無機材料など からなる全反射を利用した偏光子、等を用いることができる。  Further, as the above-mentioned polarization selecting means, a polarizer or a birefringent material utilizing absorption of light in a specific wavelength region obtained by dispersing a uniaxial dichroic dye or the like in a transparent film or the like is used. A polarizer using the obtained diffraction, a polarizer using total reflection made of an inorganic material such as a Glan-Thompson prism, or the like can be used.
[0046] 位相補正素子として用いる場合は、前記液晶層は、その選択反射波長が、前記液 晶変調素子の入射光の波長より短い波長にあって、電圧非印加時の前記入射光の 旋光角度がほぼゼロとなるようにし、前記電極のうちの少なくとも一方の電極は、基板 面内で基板間電圧の分布を生じるように形成して、前記基板間電圧の分布に応じた 変化を液晶層の屈折率に生じさせることによって前記入射光の波面を変化させるよう にする。 When used as a phase correction element, the liquid crystal layer has a selective reflection wavelength at a wavelength shorter than the wavelength of the incident light of the liquid crystal modulation element, and the optical rotation angle of the incident light when no voltage is applied. Is substantially zero, and at least one of the electrodes is formed so as to generate an inter-substrate voltage distribution in the plane of the substrate, and changes in the liquid crystal layer according to the inter-substrate voltage distribution are generated. By changing the wavefront of the incident light by causing it to have a refractive index To.
[0047] このように構成することにより、基板間電圧の分布に応じた液晶層の屈折率変化を 生じさせることができ、これにより透過光の位相を変化させて偏光依存性なしで波面 収差を補正できる液晶光変調素子を実現できる。  With this configuration, it is possible to cause a change in the refractive index of the liquid crystal layer according to the distribution of the voltage between the substrates, thereby changing the phase of the transmitted light to reduce the wavefront aberration without polarization dependence. A liquid crystal light modulation element that can be corrected can be realized.
[0048] また、基板間電圧に分布を生じさせる手段としては、例えば、上記の一対の基板に 形成された電極のうちの一方を分割して分割された電極部分ごとに印加電圧を異な らせること〖こより行える。この場合は、補正する波面の形状に応じて電極の形状を選 択すればよぐ例えば球面収差を補正する場合は、同心の円状または環状の分割電 極などを用いることができる。また、連続的に変化する波面収差を精度よく補正する ためには、電極の一部を他の部分に比べて高電気抵抗の膜で形成して、電極面内 に連続的に電位分布を持たせるようにしてもよい。さらに、このような連続的な電位分 布を持たせることができる電極と上記の分割電極とを併せ持つ構成でもよい。  As a means for generating a distribution in the inter-substrate voltage, for example, one of the electrodes formed on the pair of substrates is divided so that the applied voltage differs for each of the divided electrode portions. You can do this from In this case, the shape of the electrode may be selected in accordance with the shape of the wavefront to be corrected. For example, when spherical aberration is corrected, concentric circular or annular split electrodes can be used. In addition, in order to accurately correct continuously changing wavefront aberration, a part of the electrode is formed of a film having higher electric resistance than other parts, and a potential distribution is continuously provided in the electrode surface. You may make it do. Further, a configuration having both the electrode capable of providing such a continuous potential distribution and the above-mentioned divided electrode may be employed.
[0049] 電極のうちの一方を分割して分割された電極部分ごとに印加電圧を異ならせること により行う場合は、特開 2003— 123304号公報に記載されている方法で行うことがで きる。この場合は、それぞれの分割電極ごとに電位が異なるようにして、液晶層に印 加される電圧を基板面内で変化させるもので、各分割電極内で電位は一定になる。  In the case where one of the electrodes is divided and the applied voltage is made different for each of the divided electrode portions, a method described in JP-A-2003-123304 can be used. In this case, the voltage applied to the liquid crystal layer is changed in the substrate surface so that the potential is different for each divided electrode, and the potential is constant in each divided electrode.
[0050] 一方、電極の一部を他の部分に比べて高電気抵抗の膜で形成して、電極面内に 連続的に電位分布を持たせることにより行う場合は、特開 2001— 143303号公報に 記載された要領で行うことができる。具体的には以下のようになる。  On the other hand, in the case where a part of the electrode is formed by a film having a higher electric resistance than the other part and a potential distribution is continuously provided in the electrode surface, it is disclosed in Japanese Patent Application Laid-Open No. 2001-143303. This can be done as described in the gazette. Specifically, it is as follows.
[0051] まず、少なくとも一方の基板上の、電極の面内の異なる位置に、異なる電圧を供給 するための 2つ以上の給電部を形成する。異なる電圧を供給するための 2つ以上の 給電部を形成する電極としては、連続した 1枚の電極でもよいし、 1枚の電極を複数 個に分割した分割電極でもよ ヽ。分割電極に異なる電圧を供給するための 2つ以上 の給電部を形成する場合は、すべての分割電極に異なる電圧を供給するための 2つ 以上の給電部を形成してもよ ヽし、一部の分割電極に異なる電圧を供給するための 2つ以上の給電部を形成してもよ 、。  First, two or more power supply units for supplying different voltages are formed at different positions in the plane of the electrode on at least one substrate. The electrodes forming two or more power supply units for supplying different voltages may be a single continuous electrode or a divided electrode obtained by dividing one electrode into a plurality of electrodes. When two or more power supply units for supplying different voltages to the divided electrodes are formed, two or more power supply units for supplying different voltages to all the divided electrodes may be formed. Two or more power supply units for supplying different voltages to the divided electrodes of the unit may be formed.
[0052] 給電部の数は目的や形状によって異なる力 1つの電極に 10個程度あれば必要な 量だけ波面を変化させることができる。 [0053] 給電部を形成する給電部材料のシート抵抗 と給電部以外の電極材料のシート [0052] The number of power supply sections varies depending on the purpose and shape. If about 10 electrodes are provided for one electrode, the wavefront can be changed by a necessary amount. [0053] The sheet resistance of the power supply part material forming the power supply part and the sheet of the electrode material other than the power supply part
S  S
抵抗 P との比 p / β は、 1000以上にすることが好ましい。 / β 力 、さい場合 The ratio p / β to the resistance P is preferably set to 1000 or more. / β force, in case
T T S T S T T S T S
、給電部以外にも比較的大きな電流が流れ、給電部内で電圧降下が生じて、所望の 電圧分布を得ることが困難となることがある。したがって、給電部材料に比べ給電部 以外の電極材料のシート抵抗が高いほど、隣接する給電部間で電位を連続的に変 化させやすぐ所望の電位分布を得ることができる。 / ρ を 1000以上にすること  In addition, a relatively large current flows in portions other than the power supply portion, and a voltage drop occurs in the power supply portion, which may make it difficult to obtain a desired voltage distribution. Therefore, as the sheet resistance of the electrode material other than the power supply portion is higher than that of the power supply portion material, the potential can be continuously changed between adjacent power supply portions and a desired potential distribution can be obtained immediately. / ρ must be 1000 or more
T S  T S
力 sこの条件を満たすための目安である。  Force s is a measure to meet this condition.
[0054] しかし ρ が大きすぎると給電部の導電性がなくなり電位分布は発生しない。したが  [0054] However, if ρ is too large, the conductivity of the power supply unit is lost, and no potential distribution occurs. But
Τ  Τ
つて Ρ をできるだけ小さくする方が望ましぐ ρ は 0. 1— 10 Ω Ζ口程度、 Ρ は 100 Therefore, it is desirable to make Ρ as small as possible. Ρ is about 0.1—10 Ω, and Ρ is 100
S S Τ S S Τ
一 lOOkQ Z口程度がよい。  One lOOkQ Z mouth is good.
[0055] 以上の条件を満足し適切に p と を設定すると、一方の電極のみに 2つ以上の [0055] When the above conditions are satisfied and p and are appropriately set, two or more
S T  S T
給電部を形成しこれら 2つ以上の給電部にそれぞれ異なる電圧を供給した場合、そ れぞれの給電部内では等電位となるが、給電部以外の電極面内の電位分布は給電 部間で発生する電圧降下により連続的に変化する。  When a power supply unit is formed and different voltages are supplied to these two or more power supply units, the potential becomes equal in each of the power supply units, but the potential distribution in the electrode surface other than the power supply unit differs between the power supply units. It changes continuously due to the generated voltage drop.
[0056] 給電部材料としては、銅、金、アルミニウム、クロムなどの金属材料が導電性 '耐久 性の点力も好ましいが、電気抵抗率が室温で 10— 8— 10— 7 Ω ·πι程度であれば金属以 外の材料でもよい。 [0056] The feeding portion materials include copper, gold, aluminum, metal material such as chrome point force of conductive 'durability preferred, the electrical resistivity at room temperature 10- 8 - 10- 7 Ω · at about πι If it is, a material other than metal may be used.
[0057] 給電部の形状や大きさは、補正した!/、波面収差に応じて変化させることが好ま 、 。すなわち位相補正素子により発生する波面の変化は、給電部の形状や大きさなど に依存し、補正した 、波面収差の種類や発生させた!/、波面形状に応じて変化させれ ばよい。ここで、波面収差としてはコマ収差、球面収差、非点収差などがある。たとえ ば、球面収差を補正する場合は、球面収差が光軸を中心とする同心円形状であるた め、複数の給電部は、それぞれが同心の円環状に配設されていることが好ましい。  It is preferable that the shape and size of the power supply unit are corrected! /, And are changed in accordance with the wavefront aberration. That is, the change in the wavefront generated by the phase correction element depends on the shape and size of the power supply unit, and may be changed according to the type of the corrected wavefront aberration, the generated wavefront shape, and the wavefront shape. Here, the wavefront aberration includes coma, spherical aberration, astigmatism and the like. For example, when correcting spherical aberration, since the spherical aberration has a concentric shape centered on the optical axis, it is preferable that each of the plurality of power supply units is arranged in a concentric annular shape.
[0058] また、この場合の液晶層の選択反射波長は、第 2の入射光の旋光性がほぼ 0になる ように第 2の入射光の波長に対して充分に小さい方がよい。具体的には、液晶層の、 選択反射波長の入射光側の反射端は、第 2の入射光の波長に対して lOOnm以上、 好ましくは 200nm以上小さいほうがよい。ただし、小さくなり過ぎるとコレステリック液 晶を駆動させる電圧が大きくなるので、駆動電圧が大きくなりすぎない程度に小さく することが好ましい。具体的には選択反射波長の吸収端のうち、入射光の波長に近In this case, it is preferable that the selective reflection wavelength of the liquid crystal layer is sufficiently smaller than the wavelength of the second incident light so that the optical rotation of the second incident light becomes almost zero. Specifically, the reflection end on the incident light side of the selective reflection wavelength of the liquid crystal layer is preferably 100 nm or more, preferably 200 nm or more smaller than the wavelength of the second incident light. However, if the voltage is too small, the voltage for driving the cholesteric liquid crystal will increase. It is preferable to do. Specifically, of the absorption edges of the selective reflection wavelength, the wavelength near the wavelength of the incident light
V、方の吸収端が、 300nm以上の波長にあることが好まし!/、。 V, it is preferable that the absorption edge is at a wavelength of 300 nm or more!
実施例  Example
[0059] 上記の本発明の実施の形態に基づく具体的な実施例を、以下に図面を用いて説 明する。  A specific example based on the above-described embodiment of the present invention will be described below with reference to the drawings.
図 1は、本実施例に係る液晶光変調素子の構成を概念的に示す側断面図である。こ こで、本実施例に係る液晶光変調素子は、光減衰器 200として実現されるものである 。以下、光減衰器 200を、液晶光変調素子 (光減衰器) 200という。  FIG. 1 is a side sectional view conceptually showing the configuration of the liquid crystal light modulation device according to the present embodiment. Here, the liquid crystal light modulation device according to the present embodiment is realized as an optical attenuator 200. Hereinafter, the optical attenuator 200 is referred to as a liquid crystal light modulation element (optical attenuator) 200.
[0060] 液晶光変調素子 (光減衰器） 200の液晶層 1の材料として、ネマティック液晶（チッソ 社製、商品番号: JC-1041XX)を 50. 4質量％、ネマティック液晶 (東京化成工業社 製、商品番号: 5CB)を 35. 6質量％、ねじり力が約 30[lZ w m]で右螺旋のカイラ ル剤 (メルク社製、商品番号: ZLI— 4572)を 6. 28質量％、液晶性二官能アタリレー ト (メルク社製、商品番号: RM257)を 5. 02質量％、および非液晶性単官能アタリレ ート（2-ェチルへキシルアタリレート、 Aldrich社製）を 2. 42質量0 /0、重合開始剤（2 , 2-ジメトキシ -2-フエ-ルァセトフエノン、東京化成工業社製)を 0. 28質量0 /0混合 し、液晶組成物を得た (なお、各成分の構造は特開 2003— 327966号公報を参照。 As a material of the liquid crystal layer 1 of the liquid crystal light modulator (optical attenuator) 200, 50.4% by mass of a nematic liquid crystal (manufactured by Chisso Corporation, product number: JC-1041XX), and a nematic liquid crystal (manufactured by Tokyo Chemical Industry Co., Ltd.) 35.6% by mass, product number: 5CB), 6.28% by mass of a right-handed chiral agent (Merck, product number: ZLI-4572) with a torsional force of about 30 [lZ wm], liquid crystal bifunctional Atarire preparative (Merck, product number: RM257) a 5.02 mass%, and non-liquid crystal monofunctional Atarire over preparative (hexyl Atari rate to 2 Echiru, Aldrich Co., Ltd.) 2.42 mass 0 / 0, the polymerization initiator (2, 2-dimethoxy-2-Hue - Ruasetofuenon, manufactured by Tokyo Kasei Kogyo Co., Ltd.) was 0.28 mass 0/0 mixture to obtain a liquid crystal composition (the structure of each component is especially Open 2003—see 327966.
) o  ) o
[0061] 各成分の配合割合は、ネマティック液晶、カイラル剤、液晶性二官能アタリレート、 非液晶性単官能アタリレート、および重合開始剤の総量に対する各成分の割合であ る。  [0061] The compounding ratio of each component is the ratio of each component to the total amount of the nematic liquid crystal, the chiral agent, the liquid crystalline bifunctional acrylate, the non-liquid crystalline monofunctional acrylate, and the polymerization initiator.
[0062] また、 JC 1041XXと 5CBとを混合して得られた混合ネマティック液晶の常光屈折 率 n = 1. 52、異常光屈折率 n = 1. 68であり、この液晶組成物の選択反射波長は ο e  [0062] Also, the mixed nematic liquid crystal obtained by mixing JC 1041XX and 5CB has an ordinary refractive index n = 1.52 and an extraordinary refractive index n = 1.68, and the selective reflection wavelength of this liquid crystal composition Is ο e
約 610nmであった。  It was about 610 nm.
[0063] 次に、基板 5、 6上に、 ITO力もなる電極 3、 4を形成し、その上にさらに不図示の水 平配向膜を形成し、ラビング処理を施した。図 1のように電極 3、 4および水平配向膜 を形成した基板 5、 6と、液晶用スぺーサが混合されたシール材 2とで形成したセルの 中に、上記のように調製した液晶組成物を封入し、厚さ dieが 10 mの液晶層 1とし [0064] 次に、液晶層 1に波長 365nmの紫外光を lOmWZcm2で照射して高分子安定ィ匕 コレステリック液晶を形成し、液晶セル 110を作製した。 Next, electrodes 3 and 4 having ITO power were formed on substrates 5 and 6, and a horizontal alignment film (not shown) was further formed thereon, followed by rubbing. The liquid crystal prepared as described above was placed in a cell formed by substrates 5 and 6 on which electrodes 3 and 4 and a horizontal alignment film were formed as shown in FIG. 1, and a sealing material 2 mixed with a spacer for liquid crystal. Enclose the composition to form a liquid crystal layer 1 with a die of 10 m. Next, the liquid crystal layer 1 was irradiated with ultraviolet light having a wavelength of 365 nm at 10 OmWZcm 2 to form a polymer-stabilized cholesteric liquid crystal, thereby producing a liquid crystal cell 110.
[0065] 次に、所定の方向の直線偏光を選択的に透過させる偏光子 7を、液晶セル 110の 光出射面側に、入射光の偏光方向（ここでは、 Y軸方向とする。）と同じ Y軸方向に偏 光方向が向くように接着固定し、液晶光変調素子 (光減衰器) 200を製作した。  Next, a polarizer 7 for selectively transmitting linearly polarized light in a predetermined direction is provided on the light emission surface side of the liquid crystal cell 110 with the polarization direction of the incident light (here, the Y-axis direction). The liquid crystal light modulation device (optical attenuator) 200 was manufactured by adhesively fixing the polarization direction to the same Y-axis direction.
[0066] これを実験用素子とし、上記の液晶セル 110を作成し、電圧を印加せずに波長 43 Onmから 780nmまでの直線偏光を入射させ、出射光の旋光角度、楕円率、および、 透過率を測定した。図 3は、これらの結果を示すグラフである。  Using this as an experimental element, the above-described liquid crystal cell 110 was prepared, linearly polarized light having a wavelength of 43 Onm to 780 nm was incident without applying a voltage, and the optical rotation angle, ellipticity, and transmission of the emitted light were measured. The rate was measured. FIG. 3 is a graph showing these results.
[0067] 図 3に示すグラフから、本実施例の液晶層の選択反射波長の長波長側の反射端は 650nm付近にあり、波長 660nmの入射光に対しては、透過光は楕円率がほぼ 0の 直線偏光であり、旋光角度が約 70° であることがわかる。したがって、波長 660nm の光に対するこの液晶光変調素子の透過率は界面反射等が無い理想状態を仮定 すると、約 34% ( = cos (70° ) X 100%)になる。  From the graph shown in FIG. 3, the reflection end of the liquid crystal layer of the present example on the long wavelength side of the selective reflection wavelength is near 650 nm, and the transmitted light has almost an ellipticity with respect to the incident light having the wavelength of 660 nm. It can be seen that the light is linearly polarized light of 0 and the optical rotation angle is about 70 °. Therefore, the transmittance of the liquid crystal light modulation element for light having a wavelength of 660 nm is about 34% (= cos (70 °) × 100%) assuming an ideal state without interface reflection and the like.
[0068] 一方、充分な電圧を印カロした時には、液晶分子は基板と垂直な方向を向くため旋 光角度がほぼゼロとなり、理想状態では、この液晶光変調素子の透過率はほぼ 100 %になる。このため、この液晶光変調素子は波長 660nmの入射光に対してコントラス トが約 3 : 1となる光減衰器として作用することになる。  On the other hand, when a sufficient voltage is applied, the liquid crystal molecules are oriented in a direction perpendicular to the substrate, so that the optical rotation angle becomes almost zero. In an ideal state, the transmittance of this liquid crystal light modulation element becomes almost 100%. Become. For this reason, this liquid crystal light modulation element acts as an optical attenuator with a contrast of about 3: 1 for incident light having a wavelength of 660 nm.
[0069] また、波長 780nmの入射光に対しては、図 3に示すグラフから、楕円率がほぼ 0の 直線偏光であることが分かり、旋光性を示さない (旋光角度がゼロ）ことから、上記の 偏光子を透過する光は電圧非印加時に約 100%の透過率で透過することが分かる。 また、電圧印加時の透過率は、波長 660nmの入射光について説明した理由と同じ 理由で 100%となり、波長 780nmの入射光に対しては光減衰器として作用しな!/、こ とになる。  For the incident light having a wavelength of 780 nm, the graph shown in FIG. 3 indicates that the light is linearly polarized light having an ellipticity of almost 0, and does not exhibit optical rotation (the optical rotation angle is zero). It can be seen that the light transmitted through the polarizer is transmitted with a transmittance of about 100% when no voltage is applied. In addition, the transmittance when voltage is applied becomes 100% for the same reason as described for the incident light with a wavelength of 660 nm, and does not act as an optical attenuator for the incident light with a wavelength of 780 nm! / .
[0070] また、矩形波交流電源 8を用いて、実験用素子として製作した液晶セル 110に lkH zの矩形波電圧を印加したが、電圧印加過程および電圧遮断過程の!、ずれでもフォ 一カルコニック状態の出現による光散乱状態は観察されな力つた。  [0070] In addition, a rectangular wave voltage of lkHz was applied to the liquid crystal cell 110 manufactured as an experimental device using the rectangular wave AC power supply 8, but! The light scattering state due to the appearance of the state was not observed.
[0071] 次に、この実験用素子として製作した液晶セル 110に 1kHzの矩形波電圧を印加し て、波長 750nmで屈折率の変化を測定した。 [0072] その結果、屈折率が等方的に 0. 08程度減少することが確認できた。このことから、 電極 3、 4のうちの一方を分割するなどの手段によって、補正しょうとする波面収差に 応じて基板面内で基板間電圧の分布を生じるように形成して、前記基板間電圧の分 布に応じた変化を液晶層の屈折率に生じさせることにより、前記入射光の波面を変 ィ匕させることが可會である。 Next, a 1 kHz rectangular wave voltage was applied to the liquid crystal cell 110 manufactured as this experimental element, and the change in the refractive index was measured at a wavelength of 750 nm. As a result, it was confirmed that the refractive index isotropically decreased by about 0.08. From this, by forming one of the electrodes 3 and 4 so as to generate a distribution of the inter-substrate voltage in the substrate surface in accordance with the wavefront aberration to be corrected, the inter-substrate voltage is formed. By changing the refractive index of the liquid crystal layer according to the distribution, the wavefront of the incident light can be changed.
[0073] 以下に、本発明の液晶光変調素子を位相補正として用いる場合の具体例を説明 する。図 4は対物レンズの NAが 0. 65、光源の波長が 0. 4 mの光学系において、 光ディスクの厚みが設計値の 0. 6mmより 0. 03mm厚くなつた場合に発生する波面 収差 (球面収差)を示す図である。光ディスクが設計値より厚 、場合は有効瞳の中心 と有効瞳の周辺部の位相に対して、その両者に挟まれた中間部の位相が進んだ状 態となり、光ディスクが設計値より薄い場合は位相が遅れた状態となる。本例におけ る位相補正素子の電極パターンを図 5に示す。  Hereinafter, a specific example in the case where the liquid crystal light modulation device of the present invention is used for phase correction will be described. Figure 4 shows the wavefront aberration (spherical surface) that occurs when the thickness of the optical disk is 0.03 mm thicker than the design value of 0.6 mm in an optical system with an objective lens NA of 0.65 and a light source wavelength of 0.4 m. FIG. If the optical disk is thicker than the design value, the phase of the middle part sandwiched between the center of the effective pupil and the peripheral part of the effective pupil is advanced, and if the optical disk is thinner than the design value, The phase is delayed. Fig. 5 shows the electrode pattern of the phase correction element in this example.
[0074] 図 5中の斜線部は ITO膜で形成された、連続した 1枚の透明電極 80であり太線部 分は給電部として機能するメタル電極 81— 83である。メタル電極 81-83はメタル配 線 84によりそれぞれ外部の信号源に接続されており、信号 1一 3より各々任意の電圧 を供給できる。  The hatched portions in FIG. 5 are one continuous transparent electrode 80 formed of an ITO film, and the thick line portions are metal electrodes 81 to 83 functioning as a power supply unit. Each of the metal electrodes 81-83 is connected to an external signal source via a metal wiring 84, and can supply an arbitrary voltage from each of the signals 113.
[0075] 電極パターンは以下のように形成する。まず、ガラス基板にスパッタリング法にて IT O膜を形成した後、フォトリソグラフィ一の技術を用いてパターユングする。このとき、メ タル電極 81— 83が形成される部分は ITO膜を残し、メタル電極 82、 83に接続され ているメタル配線部は透明電極 80と絶縁されるようエッチングによりメタル配線部周 囲の ITO膜を除去する。次に図 5のメタル電極 82、 83およびメタル配線を形成する。 ここで使用したメタル電極材はアルミニウムである。  [0075] The electrode pattern is formed as follows. First, an ITO film is formed on a glass substrate by a sputtering method, and then patterned using a photolithography technique. At this time, the portion where the metal electrodes 81-83 are formed leaves the ITO film, and the metal wiring portion connected to the metal electrodes 82 and 83 is etched around the metal wiring portion so as to be insulated from the transparent electrode 80. Remove the ITO film. Next, metal electrodes 82 and 83 and metal wiring of FIG. 5 are formed. The metal electrode material used here is aluminum.
[0076] 図 5のメタル電極 81と 82の外径はそれぞれ 4mmと 3mm、幅はいずれも 100 μ mま たメタル電極 83の直径は 200 μ mとする。  The outer diameters of metal electrodes 81 and 82 in FIG. 5 are 4 mm and 3 mm, respectively, the width is 100 μm, and the diameter of metal electrode 83 is 200 μm.
[0077] 0. 03mmの光ディスク厚みムラにより発生する球面収差を位相補正素子により補 正するために、メタル電極 81、 82、 83に適当な電圧を供給する。 3個の給電部 (メタ ル電極）を有する電極に対向する電極は給電部が 1つの連続した 1枚の透明電極で 構成されており、常に OVの電位になっている。 [0078] 透明電極 80には各メタル電極の電圧にしたがって電圧分布を生じる。電圧分布に より液晶に実質的な屈折率分布が生じる結果、位相補正素子は同心円状の位相変 化を発生できる。 An appropriate voltage is supplied to the metal electrodes 81, 82, and 83 in order to correct the spherical aberration generated by the thickness unevenness of the optical disk of 0.03 mm by the phase correction element. The electrode facing the electrode with three power supply parts (metal electrodes) is composed of one continuous transparent electrode with one power supply part, and is always at the OV potential. [0078] A voltage distribution is generated in the transparent electrode 80 according to the voltage of each metal electrode. As a result of the voltage distribution producing a substantial refractive index distribution in the liquid crystal, the phase correction element can generate concentric phase changes.
産業上の利用可能性  Industrial applicability
[0079] 本発明にかかる液晶光変調素子は、コレステリック液晶を用いる液晶光変調素子に おいて、電圧印加過程および電圧遮断過程で、フォーカルコニック状態の出現によ る光散乱状態が発生しない液晶光変調素子であり、光通信または光ヘッド装置等に 用!/、ることができる。 なお、本発明の明細書には、本出願の優先権主張の基礎となる日本特許出願 200 4 044742 (2004年 2月 20日出願）の明細書の全内容をここに引用し、発明の開示 として取り込むものである。 [0079] The liquid crystal light modulation device according to the present invention is a liquid crystal light modulation device using cholesteric liquid crystal, in which a light scattering state due to the appearance of a focal conic state does not occur in a voltage application process and a voltage cutoff process. It is a modulation element and can be used for optical communication or optical head devices. In the specification of the present invention, the entire contents of the specification of Japanese Patent Application No. 2004 044742 (filed on Feb. 20, 2004), which is the basis of the priority claim of the present application, are cited, and the disclosure of the invention is disclosed. It is taken in as.

Claims

請求の範囲 The scope of the claims
[1] 対向して配置された一対の基板、前記それぞれの基板の相対向する表面に形成さ れた電極、および前記一対の基板間に狭持された液晶層を備え、所定の波長の入 射光に対して変調を行う液晶光変調素子であって、  [1] A pair of substrates arranged opposite to each other, electrodes formed on opposing surfaces of the respective substrates, and a liquid crystal layer sandwiched between the pair of substrates are provided. A liquid crystal light modulation element that modulates emitted light,
前記液晶層は、コレステリック液晶と、非液晶性単官能重合性モノマーと、液晶性 多官能重合性モノマーとを含む液晶組成物を重合させてなる高分子安定化コレステ リック液晶からなり、電圧印加過程および電圧遮断過程の!/、ずれでもフォーカルコ- ック状態の出現による光散乱状態が発生しないことを特徴とする液晶光変調素子。  The liquid crystal layer is composed of a polymer-stabilized cholesteric liquid crystal obtained by polymerizing a liquid crystal composition containing a cholesteric liquid crystal, a non-liquid crystal monofunctional polymerizable monomer, and a liquid crystal polyfunctional polymerizable monomer. A liquid crystal light modulation element characterized in that a light scattering state does not occur due to the appearance of a focal cock state even if the voltage cutoff process is! /, Even if it deviates.
[2] 前記高分子安定化コレステリック液晶が、  [2] The polymer-stabilized cholesteric liquid crystal is
前記液晶組成物中のコレステリック液晶と、非液晶性単官能重合性モノマーと、液 晶性多官能重合性モノマーとの総量に対して、非液晶性単官能重合性モノマーを 1 一 5質量％含み、かつ、液晶性多官能重合性モノマーを 3— 7質量％含む液晶組成 物を重合させてなる高分子安定ィ匕コレステリック液晶である、請求項 1に記載の液晶 光変調素子。  The liquid crystal composition contains 115% by mass of the non-liquid crystalline monofunctional polymerizable monomer, based on the total amount of the cholesteric liquid crystal, the non-liquid crystalline monofunctional polymerizable monomer, and the liquid crystalline polyfunctional polymerizable monomer. 2. The liquid crystal light modulation device according to claim 1, which is a polymer-stabilized cholesteric liquid crystal obtained by polymerizing a liquid crystal composition containing 3 to 7% by mass of a liquid crystalline polyfunctional polymerizable monomer.
[3] 前記液晶光変調素子は、さらに、光出射面側に所定の方向の直線偏光を選択的 に透過する偏光選択手段を備え、  [3] The liquid crystal light modulation device further includes a polarization selection unit on the light emission surface side for selectively transmitting linearly polarized light in a predetermined direction,
前記液晶層は、その選択反射波長が前記液晶光変調素子の入射光の波長近傍 にあって、電圧非印加時における、前記入射光が透過する際の旋光角度が 0° を超 えて 180° 未満の範囲内にあり、  The liquid crystal layer has a selective reflection wavelength in the vicinity of the wavelength of the incident light of the liquid crystal light modulation element, and an optical rotation angle when the incident light is transmitted is more than 0 ° and less than 180 ° when no voltage is applied. Within the range of
電極への電圧の印加、非印加の別に応じて入射光の透過率が変化する、請求項 1 または 2の 、ずれかに記載の液晶光変調素子。  3. The liquid crystal light modulation device according to claim 1, wherein the transmittance of incident light changes depending on whether a voltage is applied to the electrode or not.
[4] 前記液晶層は、電圧非印加時における、前記入射光が透過する際の旋光角度が 2[4] The liquid crystal layer has an optical rotation angle of 2 when the incident light is transmitted when no voltage is applied.
0— 160° の範囲内にある請求項 3に記載の液晶光変調素子。 4. The liquid crystal light modulator according to claim 3, wherein the angle is within a range of 0 to 160 °.
[5] 前記液晶光変調素子は、さらに、光出射面側に所定の方向の直線偏光を選択的 に透過する偏光選択手段を備え、 [5] The liquid crystal light modulation device further includes a polarization selection unit on the light emission surface side for selectively transmitting linearly polarized light in a predetermined direction,
前記液晶光変調素子に入射する入射光には第 1の波長を有する第 1の入射光と第 2の波長を有する第 2の入射光とがあり、  The incident light incident on the liquid crystal light modulation element includes a first incident light having a first wavelength and a second incident light having a second wavelength,
前記液晶層は、その選択反射波長が前記第 1の波長近傍であって前記第 2の波長 より短い波長にあり、第 1の入射光に対しては、電圧非印加時における前記第 1の入 射光が透過する際の旋光角度が 0° を超えて 180° 未満の範囲内にあり、第 2の入 射光に対しては、電圧非印加時における前記第 2の入射光が透過する際の旋光角 度が実質的にゼロとなっており、 The liquid crystal layer has a selective reflection wavelength near the first wavelength and the second wavelength. At a shorter wavelength, and for the first incident light, the optical rotation angle when the first incident light transmits when no voltage is applied is within a range of more than 0 ° and less than 180 °, With respect to the incident light of No. 2, the optical rotation angle when the second incident light passes when no voltage is applied is substantially zero,
第 1の入射光に対しては電極への電圧の印加、非印加の別に応じて透過率が変化 し、第 2の入射光に対しては、電極への電圧の印カロ、非印加にかかわらず透過率が 実質的に変化しない、請求項 1または 2に記載の液晶光変調素子。  For the first incident light, the transmittance changes depending on whether voltage is applied to the electrode or not, and for the second incident light, the voltage is applied to the electrode regardless of whether the voltage is applied to the electrode or not. 3. The liquid crystal light modulation element according to claim 1, wherein the transmittance does not substantially change.
[6] 前記液晶層は、電圧非印加時における、前記第 1の入射光が透過する際の旋光角 度が 20— 160° の範囲内にある請求項 5に記載の液晶光変調素子。  6. The liquid crystal light modulation device according to claim 5, wherein the liquid crystal layer has an optical rotation angle of 20 to 160 ° when the first incident light is transmitted when no voltage is applied.
[7] 前記液晶層は、その選択反射波長が、前記液晶変調素子の入射光の波長より短 い波長にあって、電圧非印加時の前記入射光が透過する際の旋光角度が実質的に ゼロとなっており、  [7] In the liquid crystal layer, the selective reflection wavelength is at a wavelength shorter than the wavelength of the incident light of the liquid crystal modulation element, and the optical rotation angle when the incident light is transmitted when no voltage is applied is substantially. It is zero,
前記電極のうちの少なくとも一方の電極は、基板面内で基板間電圧の分布を生じ るように形成されており、前記基板間電圧の分布に応じた変化を液晶層の屈折率に 生じさせることによって前記入射光の波面を変化させる、請求項 1または 2のいずれ かに記載の液晶光変調素子。  At least one of the electrodes is formed so as to generate an inter-substrate voltage distribution in a substrate plane, and causes a change in the refractive index of the liquid crystal layer in accordance with the inter-substrate voltage distribution. The liquid crystal light modulation device according to claim 1, wherein a wavefront of the incident light is changed by the change.
[8] 前記一対の基板に形成された電極のうちの少なくとも一方を分割して複数の電極 部分を形成し、その電極部分ごとに印加電圧を異ならせることによって、基板面内で 基板間電圧の分布を生じさせる、請求項 7に記載の液晶光変調素子。  [8] At least one of the electrodes formed on the pair of substrates is divided to form a plurality of electrode portions, and the applied voltage is varied for each of the electrode portions, so that the inter-substrate voltage in the substrate surface is reduced. 8. The liquid crystal light modulation element according to claim 7, which causes distribution.
[9] 前記一対の基板に形成された電極の一部を他の部分に比べて高電気抵抗の膜で 形成し、電極面内に電位の分布を持たせることによって、基板面内で基板間電圧の 分布を生じさせる、請求項 7または 8に記載の液晶光変調素子。  [9] A part of the electrodes formed on the pair of substrates is formed of a film having a higher electric resistance than the other parts, and a potential distribution is provided in the electrode surface, so that the distance between the substrates in the substrate surface is reduced. 9. The liquid crystal light modulation element according to claim 7, which generates a voltage distribution.
[10] コレステリック液晶と、非液晶性単官能重合性モノマーと、液晶性多官能重合性モ ノマーとを含む液晶組成物であって、  [10] A liquid crystal composition comprising a cholesteric liquid crystal, a non-liquid crystalline monofunctional polymerizable monomer, and a liquid crystalline polyfunctional polymerizable monomer,
コレステリック液晶と、非液晶性単官能重合性モノマーと、液晶性多官能重合性モ ノマーとの総量に対して、非液晶性単官能重合性モノマーを 1一 5質量％含み、かつ 、液晶性多官能重合性モノマーを 3— 7質量％含む液晶組成物を重合させてなる高 分子安定化コレステリック液晶。  The cholesteric liquid crystal, the non-liquid crystalline monofunctional polymerizable monomer, and the liquid crystalline polyfunctional polymerizable monomer contain the non-liquid crystalline monofunctional polymerizable monomer in an amount of 115% by mass and the liquid crystalline polyfunctional monomer. A high molecular weight stabilized cholesteric liquid crystal obtained by polymerizing a liquid crystal composition containing 3 to 7% by mass of a functional polymerizable monomer.
PCT/JP2005/002611 2004-02-20 2005-02-18 Liquid crystal optical modulating device WO2005081051A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2006510250A JPWO2005081051A1 (en) 2004-02-20 2005-02-18 Liquid crystal light modulator

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2004044742 2004-02-20
JP2004-044742 2004-02-20

Publications (1)

Publication Number Publication Date
WO2005081051A1 true WO2005081051A1 (en) 2005-09-01

Family

ID=34879356

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2005/002611 WO2005081051A1 (en) 2004-02-20 2005-02-18 Liquid crystal optical modulating device

Country Status (2)

Country Link
JP (1) JPWO2005081051A1 (en)
WO (1) WO2005081051A1 (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007101922A (en) * 2005-10-05 2007-04-19 Seiko Epson Corp Image display apparatus
CN102338895A (en) * 2011-09-28 2012-02-01 电子科技大学 Bifocus micro lens with aspheric surface and adjustable focal length
JP2016502145A (en) * 2012-12-14 2016-01-21 エルジー・ケム・リミテッド Polymerizable composition (POLYMERIZABLECOMPOSITION)
US9541774B2 (en) 2011-12-16 2017-01-10 Mitsui Chemicals, Inc. Control device for variable focus lenses, control method for variable focus lenses, and electronic glasses
US20210324272A1 (en) * 2018-12-21 2021-10-21 Fujifilm Corporation Liquid crystal composition, method for producing high-molecular weight liquid crystal compound, light absorption anisotropic film, laminate, and image display device

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001143303A (en) * 1999-09-02 2001-05-25 Asahi Glass Co Ltd Optical head device
JP2003327966A (en) * 2002-05-08 2003-11-19 Japan Science & Technology Corp Liquid crystal material for optical modulation element

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001143303A (en) * 1999-09-02 2001-05-25 Asahi Glass Co Ltd Optical head device
JP2003327966A (en) * 2002-05-08 2003-11-19 Japan Science & Technology Corp Liquid crystal material for optical modulation element

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007101922A (en) * 2005-10-05 2007-04-19 Seiko Epson Corp Image display apparatus
JP4600238B2 (en) * 2005-10-05 2010-12-15 セイコーエプソン株式会社 Image display device
CN102338895A (en) * 2011-09-28 2012-02-01 电子科技大学 Bifocus micro lens with aspheric surface and adjustable focal length
CN102338895B (en) * 2011-09-28 2013-11-06 电子科技大学 Bifocus micro lens with aspheric surface and adjustable focal length
US9541774B2 (en) 2011-12-16 2017-01-10 Mitsui Chemicals, Inc. Control device for variable focus lenses, control method for variable focus lenses, and electronic glasses
JP2016502145A (en) * 2012-12-14 2016-01-21 エルジー・ケム・リミテッド Polymerizable composition (POLYMERIZABLECOMPOSITION)
US9828550B2 (en) 2012-12-14 2017-11-28 Lg Chem, Ltd. Polymerizable composition and method for manufacturing liquid crystal device
US9840668B2 (en) 2012-12-14 2017-12-12 Lg Chem, Ltd. Liquid crystal device
US10370591B2 (en) 2012-12-14 2019-08-06 Lg Chem, Ltd. Liquid crystal device
US20210324272A1 (en) * 2018-12-21 2021-10-21 Fujifilm Corporation Liquid crystal composition, method for producing high-molecular weight liquid crystal compound, light absorption anisotropic film, laminate, and image display device
US11697770B2 (en) * 2018-12-21 2023-07-11 Fujifilm Corporation Liquid crystal composition, method for producing high-molecular weight liquid crystal compound, light absorption anisotropic film, laminate, and image display device

Also Published As

Publication number Publication date
JPWO2005081051A1 (en) 2007-10-25

Similar Documents

Publication Publication Date Title
KR100475467B1 (en) Liquid-crystal display device and method of fabricating the same
KR100853069B1 (en) Display element and display unit
TWI412791B (en) Double-layer liquid crystal lens apparatus
JP2006127707A (en) Aperture controlling element and optical head device
JP4580188B2 (en) Liquid crystal display device and manufacturing method thereof
WO2006132361A1 (en) Display element and display device
WO2005080529A9 (en) Liquid crystal material for optical device and optical modulation device
JPH1055003A (en) Twisted liquid crystal device, assembly and liquid crystal device
JP2000122066A (en) Liquid crystal display device
JPH1083000A (en) Twisted nematic liquid crystal device
JPWO2009069249A1 (en) Liquid crystal display device
JP2008139684A (en) Polarization converting element and polarization conversion device
WO2005081051A1 (en) Liquid crystal optical modulating device
JP2007025143A (en) Liquid crystal optical element and device
JPH01302226A (en) Ferroelectric liquid crystal element
KR100236577B1 (en) Deflecting device and projection-type display unit comprising the same
JP2007073088A (en) Liquid crystal lens and optical head unit
JP2005189434A (en) Wavefront control element, liquid crystal lens, and aberration compensation element
JP2002040434A (en) Liquid crystal display device having surface grating film on which multiple alignment array of axially symmetric two-dimensional surface grating is formed
JP4220748B2 (en) Liquid crystal display element, method for manufacturing liquid crystal display element, and liquid crystal display device
EP1602964A1 (en) Optical attenuator and optical head device
JP2005215631A (en) Optical device, its manufacturing method, substrate for liquid crystal orientation, and liquid crystal display device
JPH07234400A (en) Liquid crystal display device
JP2002358681A (en) Optical head device
JP4407344B2 (en) Variable focus element

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BW BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE EG ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NA NI NO NZ OM PG PH PL PT RO RU SC SD SE SG SK SL SY TJ TM TN TR TT TZ UA UG US UZ VC VN YU ZA ZM ZW

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): BW GH GM KE LS MW MZ NA SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LT LU MC NL PL PT RO SE SI SK TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG

DPEN Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed from 20040101)
121 Ep: the epo has been informed by wipo that ep was designated in this application
WWE Wipo information: entry into national phase

Ref document number: 2006510250

Country of ref document: JP

NENP Non-entry into the national phase

Ref country code: DE

WWW Wipo information: withdrawn in national office

Country of ref document: DE

122 Ep: pct application non-entry in european phase