WO2012063936A1 - Dispositif d'affichage à cristaux liquides et procédé de fabrication d'un dispositif d'affichage à cristaux liquides - Google Patents

Dispositif d'affichage à cristaux liquides et procédé de fabrication d'un dispositif d'affichage à cristaux liquides Download PDF

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WO2012063936A1
WO2012063936A1 PCT/JP2011/076057 JP2011076057W WO2012063936A1 WO 2012063936 A1 WO2012063936 A1 WO 2012063936A1 JP 2011076057 W JP2011076057 W JP 2011076057W WO 2012063936 A1 WO2012063936 A1 WO 2012063936A1
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liquid crystal
display device
alignment
crystal display
group
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PCT/JP2011/076057
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English (en)
Japanese (ja)
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健史 野間
真伸 水▲崎▼
仲西　洋平
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シャープ株式会社
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    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1337—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
    • G02F1/133753—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers with different alignment orientations or pretilt angles on a same surface, e.g. for grey scale or improved viewing angle
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1337—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
    • G02F1/133753—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers with different alignment orientations or pretilt angles on a same surface, e.g. for grey scale or improved viewing angle
    • G02F1/133757—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers with different alignment orientations or pretilt angles on a same surface, e.g. for grey scale or improved viewing angle with different alignment orientations
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1337—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
    • G02F1/13378—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers by treatment of the surface, e.g. embossing, rubbing or light irradiation
    • G02F1/133788—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers by treatment of the surface, e.g. embossing, rubbing or light irradiation by light irradiation, e.g. linearly polarised light photo-polymerisation
    • 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
    • G02F1/13712—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 the liquid crystal having negative dielectric anisotropy

Definitions

  • the present invention relates to a liquid crystal display device and a method for manufacturing the liquid crystal display device. More specifically, the present invention relates to a liquid crystal display device in which a polymer layer is formed on an alignment film in order to increase the alignment regulating force of liquid crystal, and a method for manufacturing a liquid crystal display device that can suitably form a polymer layer.
  • a liquid crystal display device is a display panel that controls light transmission / blocking (display on / off) by controlling the orientation of liquid crystal molecules having birefringence.
  • a technique for aligning liquid crystal molecules for example, a rubbing method is used in which after an alignment film material is applied, grooves are formed by a roller or the like to form an alignment film.
  • alignment control structures such as a bank-like protrusion formed of a dielectric provided on the electrode and a slit provided on the electrode
  • an alignment film material having a photo-alignment functional group instead of rubbing treatment, such as a method for controlling the alignment of liquid crystal molecules using UV and UV 2 A (Ultraviolet induced multi-domain Vertical Alignment) technology
  • UV and UV 2 A Ultraviolet induced multi-domain Vertical Alignment
  • liquid crystal molecules are aligned perpendicular to the substrate surface when no voltage is applied.
  • the liquid crystal molecules become a voltage. It is tilted and oriented at an appropriate angle.
  • a plurality of regions (domains) in which the directions in which the liquid crystal molecules fall are different from each other are formed in one pixel by slits or bank-like protrusions provided on the electrodes.
  • FIG. 8 is a diagram showing the relationship between relative luminance and gradation in a conventional liquid crystal display device.
  • FIG. 8 shows the relationship between relative luminance and gradation when the screen is viewed from the front (viewing angle 0 °) and obliquely (viewing angles 30 ° and 60 °).
  • the relative luminance is higher when viewed from an oblique direction than when the screen is viewed from the front.
  • MPD Multi-Pixel-Drive
  • a liquid crystal material containing a monomer is injected between substrates, the monomer is polymerized in a state where a voltage is applied, and a polymer in which the direction in which the liquid crystal molecules fall is memorized is stored.
  • PSA Polymer Sustained Alignment
  • FIG. 9 is a schematic cross-sectional view of the liquid crystal display device according to Patent Document 1 before the polymerization process
  • FIG. 10 is a schematic cross-sectional view of the liquid crystal display device according to Patent Document 1 after the polymerization process.
  • the array substrate 110 has a protrusion 115.
  • the monomer 105 is present in the liquid crystal layer 130 before the polymerization step.
  • the liquid crystal layer 130 is irradiated with ultraviolet light from the side of the array substrate 110 on which the light shielding mask 125 is formed while a predetermined voltage is applied to the liquid crystal layer 130 through the electrodes 113 and 123, and the polymerization of the monomer 105 is performed. Be started.
  • the light shielding mask 125 is formed on the array substrate 110 so as to cover approximately half of one pixel.
  • the monomer 105 present in the region not shielded by the light shielding mask 125 is polymerized. Thereafter, the light shielding mask 125 is removed, the entire surface of the liquid crystal panel is irradiated with ultraviolet light, and the monomer 105 remaining in the liquid crystal layer 130 is polymerized.
  • the first polymer 126 having a strong binding force on the liquid crystal molecules is formed in the region not exposed to light shielding by the light shielding mask 125 (exposure region), while the region shielded by the light shielding mask 125 (light shielding region) is formed.
  • the second polymer 127 having a weak binding force on the liquid crystal molecules is formed.
  • a region having a strong binding force on the liquid crystal molecules that is, a region having a high threshold voltage
  • a region having a low binding force on the liquid crystal molecules that is, a region having a low threshold voltage
  • the above-described method for improving white spots may cause an increase in manufacturing cost and a decrease in display characteristics.
  • MPD technology requires a structure for changing the voltage applied in the dot. For this reason, there are disadvantages in that the manufacturing cost increases and the aperture ratio decreases due to an increase in wiring and the like.
  • the protrusion is used, but it is difficult to use the region where the protrusion is disposed for display. For this reason, there was room for improvement in terms of increasing the aperture ratio and improving the luminance. Moreover, since the alignment of the liquid crystal molecules is affected by the protrusions not only in the region where the protrusions are disposed but also in the vicinity thereof, it is difficult to control the alignment to a desired orientation. For this reason, there was room for improvement in terms of improving contrast. Moreover, in the liquid crystal display device according to Patent Document 1, since a voltage is applied when polymerization is performed, there is room for improvement in that the manufacturing cost is increased.
  • the present invention has been made in view of the above situation, and viewed the screen obliquely in a halftone while suppressing deterioration of other display characteristics conventionally seen such as a decrease in aperture ratio and a decrease in contrast ratio.
  • An object of the present invention is to provide a liquid crystal display device capable of suppressing the occurrence of a so-called white spot phenomenon in which the brightness at the time is higher than the brightness when the screen is viewed from the front, and a method for manufacturing the liquid crystal display device Is.
  • the present inventors paid attention to the PSA technology as a method for suppressing the white spot phenomenon, and conducted intensive studies on monomers used in the PSA technology. As a result, it has been found that by forming a polymer layer using a bifunctional monomer on the vertical alignment film, it is possible to adjust the threshold voltage of a region whose orientation is controlled by the polymer layer. Then, the inventors have arrived at the present invention by conceiving that the above problem can be solved by changing the threshold voltage between the region controlled by the polymer layer and the region not controlled by the polymer layer. is there.
  • one aspect of the present invention is a liquid crystal display device including a pair of substrates and a liquid crystal layer sandwiched between the pair of substrates, the liquid crystal layer having negative dielectric anisotropy. And at least one of the pair of substrates is a main surface on the liquid crystal layer side of the alignment film by polymerization of an electrode, an alignment film for vertically aligning adjacent liquid crystal molecules, and at least one bifunctional monomer.
  • the first alignment region and the second alignment region have different threshold voltages.
  • a bifunctional monomer is used as a material for the polymer layer.
  • the bifunctional monomer is not particularly limited as long as it is a monomer having two reactive functional groups.
  • the reactive functional group include a functional group containing an unsaturated bond such as a double bond.
  • a polymer layer using a bifunctional monomer (1) can maintain a sufficient pretilt angle, and thus has high reliability, and (2) a polymerization rate.
  • photopolymerization is excellent in that the exposure time can be shortened, productivity can be improved, and / or manufacturing cost can be reduced.
  • the bifunctional monomer is superior in solubility in liquid crystal as compared with a polyfunctional monomer having three or more reactive functional groups, and it is easy to form a polymer layer.
  • the alignment film whose vertical alignment is controlled means an alignment film capable of realizing a liquid crystal display in a vertical alignment mode, and the liquid crystal molecules are only aligned perpendicularly to the film surface, that is, an alignment film that controls the alignment at 90 °. And an alignment film that controls the alignment of liquid crystal molecules substantially perpendicular to the film surface.
  • Substantially perpendicular means 80 ° or more, preferably 85 ° or more.
  • the threshold voltage means a voltage value that generates an electric field that causes an optical change in the liquid crystal layer and changes a display state in the liquid crystal display device.
  • the difference between the threshold voltage difference of the first alignment region and the threshold voltage of the second alignment region is preferably 0.1 V or more, and more preferably 0.5 V to 1.5 V. .
  • the pretilt angle of the liquid crystal molecules in each alignment region may be different.
  • the threshold voltage can be made different by changing the anchoring strength in each alignment region.
  • FIG. 11 is a diagram showing a change in a VT (voltage-transmittance) curve due to a difference in pretilt angle. As shown in FIG. 11, the threshold voltage increases as the pretilt angle increases.
  • the configuration of the liquid crystal display device is not particularly limited by other components as long as such components are essential.
  • the alignment film may be formed by irradiating polarized ultraviolet light to an alignment film material containing a photoreactive functional group (hereinafter, also referred to as a first embodiment). . Since the pretilt angle can be adjusted accurately by using polarized ultraviolet light, the liquid crystal display device of the first embodiment can be a photo-alignment type liquid crystal display device with excellent display quality.
  • the photoreactive functional group is preferably at least one selected from the group consisting of a chalcone group, a coumarin group, a cinnamate group, an azobenzene group, and a tolan group.
  • the orientation control can be performed with high accuracy. Therefore, the photoreactive functional group included in the group is aligned by irradiation with polarized ultraviolet light.
  • the liquid crystal display device including the alignment film to be processed can be particularly preferably used.
  • the pretilt angle of the liquid crystal molecules in the first alignment region and the pretilt angle of the liquid crystal molecules in the second alignment region are different from each other.
  • the threshold voltages of the respective alignment regions are different, thereby suppressing white spots. be able to.
  • the difference between the pretilt angle of the liquid crystal molecules in the first alignment region and the pretilt angle of the liquid crystal molecules in the second alignment region is preferably about 0.5 ° to 15 °. .
  • the pretilt angle of the liquid crystal molecules in the first alignment region is preferably 88.0 ° to 88.5 °, and the pretilt angle of the liquid crystal molecules in the second alignment region is 73.0 ° to 87. Preferably it is 5 °.
  • the pretilt angle of the liquid crystal molecules in the first alignment region is preferably larger than the pretilt angle of the liquid crystal molecules in the second alignment region. Since the pretilt angle of the liquid crystal molecules in the first alignment region is close to 90 °, the pretilt angle of the liquid crystal molecules in the second alignment region is larger than the pretilt angle of the liquid crystal molecules in the first alignment region. Is too large, the difference between the pretilt angle of the liquid crystal molecules in the first alignment region and the pretilt angle of the liquid crystal molecules in the second alignment region cannot be taken sufficiently, and a desired threshold voltage difference is obtained. May not be obtained.
  • the area of the second alignment region is preferably larger than 30% and smaller than 70% compared to the sum of the area of the first alignment region and the area of the second alignment region. If the area of the second alignment region is 30% or less, the area of the first alignment region is too large compared to the area of the second alignment region, so that white spots can be sufficiently suppressed. There is a risk that it will not be possible. On the other hand, if the area of the second alignment region is 70% or more, the area of the first alignment region is too small compared to the area of the second alignment region. You may not be able to do it. More preferably, the area of the first alignment region and the area of the second alignment region are substantially equal. Specifically, the second alignment region includes the first alignment region and the first alignment region. More preferably, it is larger than 45% and smaller than 55% compared with the total with the second alignment region.
  • the bifunctional monomer is preferably represented by the following chemical structural formula.
  • P 1 -A 1- (Z 1 -A 2 ) n -P 2 (In the formula, P 1 and P 2 (reactive functional groups) each independently represent an acrylate group, a methacrylate group, a vinyl group, a vinyloxy group, or an epoxy group.
  • a 1 and A 2 are each independently Represents a 1,4-phenylene group, a naphthalene-2,6-diyl group, an anthracene-2,6-diyl group, or a phenanthrene-2,7-diyl group, and the hydrogen atom contained in the ring structure is halogen, Z 1 may be COO, OCO, O, CO, NHCO, CONH, S, or A, which may be substituted with a methyl group, an ethyl group, or a propyl group, and may be a heterocyclic structure. 1 and A 2 or A 2 and A 2 are directly bonded. N is 0, 1 or 2.)
  • the bifunctional monomer preferably has a dinaphthyl ether skeleton.
  • the dinaphthyl ether skeleton include dinaphthyl ether skeletons represented by the following chemical formulas (1) to (4), and dimethacryloxy dinaphthyl ether represented by the following chemical formula (4) is particularly preferable.
  • a polymer layer formed of a bifunctional monomer having a dinaphthyl ether skeleton can reduce the pretilt angle. Furthermore, the amount of change in the pretilt angle can be increased by increasing the concentration of the bifunctional monomer.
  • the threshold voltage of the second alignment region is different from the threshold voltage of the first alignment region. Therefore, it is possible to adjust so that white spots can be suitably suppressed.
  • Another aspect of the present invention is a method for manufacturing a liquid crystal display device comprising a pair of substrates and a liquid crystal layer having negative dielectric anisotropy sandwiched between the pair of substrates, the manufacturing method comprising: A step of forming an electrode on at least one of the pair of substrates, a step of forming an alignment film for controlling alignment of adjacent liquid crystal molecules vertically, and a part of a main surface on the liquid crystal side of the alignment film, Forming a polymer layer for controlling the alignment of adjacent liquid crystal molecules, wherein the polymer layer is formed by shielding a part of at least one of the pair of substrates by a light shielding member, In a state where the portion is not shielded from light, the bifunctional monomer added to the liquid crystal layer is polymerized by irradiating light, and the first alignment region where the alignment film and the liquid crystal molecule are in contact with each other, the polymer layer and the liquid crystal molecule A second alignment region in contact with the pixel A step of forming, wherein the first alignment
  • the light shielding member is formed on one substrate so as to cover a part of one pixel region, for example.
  • a region that is not shielded by the light shielding member and a region that is shielded from light are generated in one pixel region.
  • the bifunctional monomer is polymerized by light irradiation, and the polymer layer is formed on the alignment film.
  • a second alignment region in which the alignment of liquid crystal molecules is controlled by the polymer layer is formed in the pixel.
  • the bifunctional monomer is not substantially polymerized in the light shielding region.
  • the liquid crystal display device can be preferably manufactured.
  • the configuration of the manufacturing method of the liquid crystal display device is not particularly limited by other components and processes as long as such components and processes are formed as essential. A preferred embodiment of the method for manufacturing the liquid crystal display device will be described below.
  • the alignment film controls the pretilt angle of liquid crystal molecules, the light shielding member shields a part of the pixel, and the light irradiation is performed without applying a voltage to the liquid crystal layer.
  • performing photopolymerization of the bifunctional monomer to form the polymer layer wherein the pretilt angle of the liquid crystal molecules in the first alignment region is greater than the pretilt angle of the liquid crystal molecules in the second alignment region. Is preferably a large value.
  • voltage application is not necessary, so that an increase in manufacturing cost can be suppressed.
  • the difference between the pretilt angle of the liquid crystal molecules in the first alignment region and the pretilt angle of the liquid crystal molecules in the second alignment region is set to a desired value, and the difference in threshold voltage is set to a desired value. Becomes easy.
  • the region that is not shielded by the light shielding member is preferably larger than 30% and smaller than 70% compared to all the regions where the liquid crystal is orientation controlled. If the volume of the second alignment region is 30% or less, the volume of the first alignment region is too large compared to the volume of the second alignment region, so that white spots can be sufficiently suppressed. There is a risk that it will not be possible. On the contrary, when the volume of the second alignment region is 70% or more, the volume of the first alignment region is too small compared to the volume of the second alignment region, so that white spots are sufficiently suppressed. You may not be able to do it. More preferably, the volume of the first alignment region is substantially equal to the volume of the second alignment region. Specifically, it is more preferable that the second alignment region is larger than 45% and smaller than 55% as compared with the total of the first alignment region and the second alignment region.
  • the liquid crystal display device it is not necessary to form protrusions on the substrate, and it is not necessary to provide MPD wiring or the like, and the first alignment region and the second alignment region having different threshold voltages can be formed. Therefore, it is possible to obtain a liquid crystal display device that is low in cost and has a high aperture ratio while suppressing white spots.
  • FIG. 3 is a schematic cross-sectional view of the liquid crystal display device according to Embodiment 1 before the polymerization step.
  • FIG. 3 is a schematic cross-sectional view after the polymerization step of the liquid crystal display device according to the first embodiment.
  • FIG. 3 is a schematic plan view showing a state in which light shielding masks are arranged to overlap in one pixel region of the array substrate of the liquid crystal display device according to the first embodiment.
  • FIG. 6 is a diagram showing measurement results of pretilt angles in Test Examples 1 to 3 and Comparative Example 1. 6 is a schematic cross-sectional view of a liquid crystal display device according to Embodiment 2 before a polymerization process.
  • FIG. 6 is a schematic cross-sectional view after a polymerization process of a liquid crystal display device according to Embodiment 2. It is a figure which shows the measurement result of the pretilt angle in Test Examples 2, 4, and 5. It is a figure which shows the relationship between the relative brightness
  • VT voltage-transmittance
  • Embodiment 1 In Embodiment 1, one type of bifunctional monomer is used to form the polymer layer.
  • the polymer layer is also referred to as a PSA (Polymer Sustained Alignment) film.
  • PSA Polymer Sustained Alignment
  • Examples of the bifunctional monomer used to form the PSA film in Embodiment 1 include those represented by the above chemical formulas (1) to (4).
  • FIG. 1 is a schematic cross-sectional view of the liquid crystal display device according to Embodiment 1 before the polymerization step
  • FIG. 2 is a schematic cross-sectional view of the liquid crystal display device according to Embodiment 1 after the polymerization step.
  • 1 and 2 are also schematic cross-sectional views of one pixel region of the liquid crystal display device.
  • FIG. 3 is a schematic plan view showing a state in which light shielding masks are arranged to overlap in one pixel region of the array substrate of the liquid crystal display device according to the first embodiment. As shown in FIGS.
  • the liquid crystal display device of Embodiment 1 is a liquid crystal cell in which an array substrate 10, a liquid crystal layer 30, and a color filter substrate 20 are arranged from the back side of the liquid crystal display device toward the observation surface side. It has.
  • the liquid crystal layer 30 sandwiched between a pair of substrates including the array substrate 10 and the color filter substrate 20 has negative dielectric anisotropy.
  • a linear polarizing plate is provided on the back side of the array substrate 10 and the observation surface side of the color filter substrate 20. For these linearly polarizing plates, a retardation plate may be further arranged to form a circularly polarizing plate.
  • the array substrate 10 includes various wirings, a thin film transistor (TFT) 44 and the like on an insulating transparent substrate 11 made of glass or the like.
  • the array substrate 10 includes a plurality of gate wirings 45 and auxiliary capacitance (Cs) wirings 43.
  • the plurality of gate lines 45 and the auxiliary capacitance (Cs) lines 43 extend in parallel to each other.
  • the array substrate 10 further includes a plurality of source lines 42 that intersect with the gate lines 45 and the auxiliary capacitance (Cs) lines 43 and extend in parallel to each other, and are provided in the vicinity of each intersection of the gate lines 45 and the source lines 42. TFT 44 is provided.
  • a pixel electrode 13 having a substantially rectangular shape is arranged in each pixel (pixel region).
  • the color filter substrate 20 includes an insulating transparent substrate 21 made of glass or the like, and a common electrode 23, a color filter, a black matrix, and the like formed on the transparent substrate 21.
  • Examples of the method for forming the pixel electrode 13 and the common electrode 23 include a sputtering method, a chemical vapor deposition (CVD) method, and a vapor deposition method.
  • the pixel electrode 13 can be patterned into a shape having a slit or a comb shape by using a photolithography method, but the pixel electrode 13 is not patterned into a shape having a slit or a comb shape, It may be a flat plate electrode formed in the pixel region.
  • a transparent metal oxide film such as indium tin oxide (ITO: Indium ⁇ ⁇ Tin Oxide) is preferably used.
  • the array substrate 10 includes an alignment film 12, and the color filter substrate 20 also includes an alignment film 22.
  • the alignment films 12 and 22 are vertical alignment films, and can preliminarily align (initially tilt) liquid crystal molecules in the vertical direction.
  • the alignment film material for forming the alignment films 12 and 22 is not particularly limited.
  • a material obtained by dissolving a polymer material in a solvent is used.
  • the polymer material include polyimide, polyamide, polyvinyl, polysiloxane, and the like.
  • the polymer material preferably contains a photoreactive functional group. Examples of the photoreactive functional group include a chalcone group, a coumarin group, a cinnamate group, an azobenzene group, and a tolan group.
  • Examples of a method for forming the alignment films 12 and 22 include a rubbing method in which grooves are formed by a roller or the like after applying an alignment film material to form an alignment film. Moreover, after apply
  • the type of light irradiated at this time is not particularly limited as long as the photoreactive functional group can be reacted to develop the alignment function. For example, polarized ultraviolet rays are suitable.
  • the bifunctional monomer 5 is present in the liquid crystal layer 30 before the bifunctional monomer polymerization step.
  • a light shielding mask 25 is provided on the outer side of the transparent substrate 21 (opposite the liquid crystal side), and shields about half of one pixel region.
  • non-polarized ultraviolet rays are irradiated from the normal direction of the transparent substrate 21.
  • a voltage may be applied to the liquid crystal layer 30 via the pixel electrode 13 and the common electrode 23, but it is preferable that no voltage is applied from the viewpoint of reducing manufacturing costs.
  • the bifunctional monomer 5 starts to be polymerized, and as shown in FIG.
  • a PSA layer 26 is formed on the alignment films 12 and 22 in a region not shielded from light.
  • the light shielding mask 25 shields the light, the PSA layer 26 is not formed, the region where the alignment films 12 and 22 and the liquid crystal layer 30 are in contact (the first alignment region 40), and the PSA layer 26 are formed.
  • a region where the liquid crystal layer 30 is in contact with the liquid crystal layer 30 (second alignment region 41) is formed. Since the PSA layer 26 changes the alignment regulating force of the alignment films 12 and 22, the first alignment region 40 and the second alignment region 41 have different alignment regulating forces. The voltages will be different from each other. In the liquid crystal display device shown in FIGS. 1 and 2, no voltage is applied, and the liquid crystal molecules are aligned substantially vertically.
  • the threshold voltage in the first alignment region is preferably larger than the threshold voltage in the second alignment region.
  • the pretilt angle of the liquid crystal molecules in the first alignment region is larger than the pretilt angle of the liquid crystal molecules in the second alignment region. It is preferable to do.
  • the threshold voltage in the first alignment region is made larger than the threshold voltage in the second alignment region. can do.
  • a preferable range of the threshold voltage in the first alignment region is 2.0V to 2.5V.
  • a preferable range of the threshold voltage in the second alignment region is 0.5V to 2.0V.
  • the light shielding mask 25 may be formed in close contact with the transparent substrate 21 or may be formed apart from the transparent substrate 21.
  • the light shielding mask 25 is not particularly limited as long as it shields light.
  • the light shielding mask 25 may be formed of a metal such as Cr or Al, or may be formed of a resin.
  • first alignment region and the second alignment region will be described in detail with reference to FIG.
  • the light shielding mask 25 is formed so as to cover approximately half of one pixel region. At this time, if the direction in which the liquid crystal molecules are aligned is divided into two in the longitudinal direction of the pixels in one pixel region before the second alignment region is formed, the second alignment region is formed. Thus, the alignment direction of the liquid crystal molecules is divided into four within one pixel.
  • the shape of the light shielding mask 25 is not limited to the example of FIG. 3, and may be, for example, a shape that bisects the longitudinal direction of one pixel region, or is arranged in a checkered pattern in one pixel region. Such a shape may be used.
  • the liquid crystal cell was shaken, the retardation was measured by the Senarmont method, and the pretilt angle was calculated by fitting using the crystal rotation method.
  • OMS-AF2 manufactured by Chuo Seiki Co., Ltd. was used.
  • a He—Ne laser irradiation device was used as a light source, and linearly polarized He—Ne laser light (wavelength 632.8 nm, output 2 mW) was irradiated.
  • the spot diameter was 1 mm and the temperature was 25 ° C.
  • Test example 1 An electrode was formed on the entire principal surface on one side of a pair of glass substrates, and an alignment film material containing polyimide having a cinnamate group that is a photoreactive functional group and an imidization ratio of 50% was applied by spin coating.
  • each glass substrate was irradiated with polarized ultraviolet rays as an alignment treatment to form a vertical alignment film.
  • the pretilt angle of the vertical alignment film was 88.1 ° to 88.5 °.
  • the two glass substrates are bonded together, and the bonded glass substrates are subjected to a pressure of 0.5 kgf / cm 2 . While being pressurized, the seal was cured by heating at 200 ° C. for 60 minutes in a nitrogen purged furnace.
  • a liquid crystal exhibiting negative dielectric anisotropy was injected into the cell produced by the above method.
  • 2,2 ′′ -dimethacryloxydinaphthyl ether which is a bifunctional monomer, was added so as to be 0.3 wt% of the entire liquid crystal composition.
  • non-polarized UV (0.33 mW / cm 2 ) was irradiated for 4 hours from the normal direction of the main surface of the glass substrate to polymerize the bifunctional monomer.
  • Test example 2 A liquid crystal cell was prepared in the same manner as in Test Example 1, except that 2,2 ′′ -dimethacryloxydinaphthyl ether, which is a bifunctional monomer, was added to the liquid crystal so as to be 0.6 wt% of the total liquid crystal composition. Was made.
  • Test example 3 Instead of adding 2,2 ′′ -dimethacryloxydinaphthyl ether to the liquid crystal so as to be 0.3 wt% of the entire liquid crystal composition, 4,4′-dimethacryloxybiphenyl was added to the liquid crystal composition.
  • a liquid crystal cell was produced in the same manner as in Test Example 1 except that it was added so as to be 0.3 wt% of the whole.
  • Comparative Example 1 A liquid crystal cell was produced in the same manner as in Test Example 1 except that the bifunctional monomer was not added to the liquid crystal and that the non-polarized UV was not irradiated.
  • Table 1 shows monomer conditions and non-polarized ultraviolet irradiation conditions in the liquid crystal display devices according to Test Examples 1 to 3 and Comparative Example 1.
  • FIG. 4 is a diagram showing measurement results of pretilt angles in Test Examples 1 to 3 and Comparative Example 1. As shown in FIG. 4, in Comparative Example 1 in which no bifunctional monomer was added, the pretilt angle was 88.3 °. On the other hand, in Test Example 1 in which 0.3 wt% of 2,2 ′′ -dimethacryloxydinaphthyl ether which is a bifunctional monomer was added, the pretilt angle was 86.5 °. In Test Example 2 in which 0.6 wt% of 2,2 ′′ -dimethacryloxydinaphthyl ether was added, the pretilt angle was 82.6 °.
  • the PSA layer formed by polymerizing 2,2 ′′ -dimethacryloxydinaphthyl ether can have a smaller pretilt angle than the alignment film. It has been found that the pretilt angle can be further reduced by increasing the concentration of oxydinaphthyl ether. That is, it was found that by adjusting the concentration of 2,2 ′′ -dimethacryloxydinaphthyl ether, the pretilt angle in the second alignment region can be controlled and the threshold voltage in the second alignment region can be adjusted. Accordingly, white spots can be suitably suppressed and contrast can be improved even if the voltage applied to all pixels is constant without changing the voltage applied to each pixel as in MPD.
  • Embodiment 2 In Embodiment 2, two types of bifunctional monomers are used to form a PSA film.
  • Examples of the photopolymerizable monomer used to form the PSA film in Embodiment 2 include those represented by the following chemical formula (5) in addition to those represented by the above chemical formulas (1) to (4). .
  • FIG. 5 is a schematic cross-sectional view of the liquid crystal display device according to the second embodiment before the polymerization step
  • FIG. 6 is a schematic cross-sectional view of the liquid crystal display device according to the second embodiment after the polymerization step.
  • the liquid crystal display device of Embodiment 2 is the same as the bifunctional monomer 5 except that the bifunctional monomer 6 is added to form the PSA layer 27 in addition to the bifunctional monomer 5. This is the same as the liquid crystal display device according to the first embodiment.
  • Test example 4 In addition to adding 2,2 ′′ -dimethacryloxydinaphthyl ether to the liquid crystal so as to be 0.6 wt% of the total liquid crystal composition, 4,4′-dimethacryloxybiphenyl was added to the liquid crystal composition. The same liquid crystal cell as in Test Example 2 was produced, except that it was added so as to be 0.1 wt% of the whole.
  • Test Example 5 In addition to adding 2,2 ′′ -dimethacryloxydinaphthyl ether to the liquid crystal so as to be 0.6 wt% of the total liquid crystal composition, 4,4′-dimethacryloxybiphenyl was added to the liquid crystal composition. The same liquid crystal cell as in Test Example 2 was produced except that it was added so as to be 0.3 wt% of the whole. 4,4′-Dimethacryloxybiphenyl was manufactured by Merck & Co., Inc.
  • Table 2 shows the monomer conditions and the non-polarized ultraviolet irradiation conditions in the liquid crystal display devices according to Test Examples 2, 4 and 5.
  • the measurement results of the pretilt angle in Test Examples 2, 4, and 5 are shown in FIG.
  • the pretilt angle in the second alignment region is controlled with high accuracy, It has been found that the threshold voltage of the second alignment region can be adjusted precisely. As a result, white spots can be suitably suppressed and contrast can be improved even if the voltage applied to all the pixels is constant without changing the voltage applied to each pixel as in MPD. As a result, the cost can be reduced and the aperture ratio can be increased.
  • the pretilt angle decreases according to the dose of unpolarized ultraviolet light.
  • the pretilt angle did not become 84 ° or less.
  • the liquid crystal display device according to the first and second embodiments may be any of a transmission type, a reflection type, and a reflection / transmission type. If it is a transmission type or a reflection / transmission type, the liquid crystal display device of Embodiment 1 further includes a backlight. The backlight is disposed on the back side of the liquid crystal cell, and is disposed such that light is transmitted through the array substrate 10, the liquid crystal layer 30, and the color filter substrate 20 in this order. In the case of a reflection type or a reflection / transmission type, the array substrate 10 includes a reflection plate for reflecting external light. Further, at least in a region where reflected light is used as a display, the polarizing plate of the color filter substrate 20 needs to be a circularly polarizing plate.
  • the liquid crystal display device may be in the form of a color filter on array (Color Filter On Array) including color filters on the array substrate 10.
  • the liquid crystal display device may be a monochrome display. In that case, the color filter does not need to be arranged.

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  • Spectroscopy & Molecular Physics (AREA)
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Abstract

La présente invention prévoit un dispositif d'affichage à cristaux liquides qui permet de supprimer des dégradations des caractéristiques d'affichage comme la diminution du rapport d'ouverture et la diminution du rapport de contraste, et qui permet de supprimer le phénomène de la tache blanche. Un premier aspect de la présente invention concerne un dispositif d'affichage à cristaux liquides équipé de deux substrats et d'une couche de cristaux liquides prise en sandwich entre lesdits deux substrats. La couche de cristaux liquides susmentionnée présente une anisotropie de constante diélectrique négative, et au moins un substrat des deux substrats susmentionnés comporte une électrode, un film d'orientation qui oriente les molécules de cristaux liquides adjacentes verticalement, et une couche polymère qui est formée d'un ou plusieurs types monomères bifonctionnels sur une partie de la face principale du film d'orientation susmentionné côté couche de cristaux liquides, et qui commande l'orientation des molécules de cristaux liquides adjacentes. En outre, il existe dans les pixels une première région d'orientation dans laquelle le film d'orientation susmentionné et les molécules de cristaux liquides sont en contact, et une seconde région d'orientation dans laquelle la couche polymère susmentionnée et les molécules de cristaux liquides sont en contact, la première région d'orientation susmentionnée et la seconde région d'orientation susmentionnée ayant des tensions seuil différentes.
PCT/JP2011/076057 2010-11-11 2011-11-11 Dispositif d'affichage à cristaux liquides et procédé de fabrication d'un dispositif d'affichage à cristaux liquides WO2012063936A1 (fr)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103626660A (zh) * 2012-08-23 2014-03-12 奇美电子股份有限公司 用于液晶层或配向层的感旋光性单体、使用其的液晶显示面板及其制作方法

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JPH08271900A (ja) * 1995-03-30 1996-10-18 Toshiba Corp 液晶表示装置
JP2002169161A (ja) * 2000-11-29 2002-06-14 Sharp Corp 液晶表示装置
JP2006267689A (ja) * 2005-03-24 2006-10-05 Sharp Corp 液晶表示装置の製造方法、及び液晶表示装置
JP2006343719A (ja) * 2005-06-08 2006-12-21 Au Optronics Corp 液晶ディスプレイパネルの製造方法
WO2010116565A1 (fr) * 2009-04-08 2010-10-14 シャープ株式会社 Dispositif d'affichage à cristaux liquides, procédé pour fabriquer un dispositif d'affichage à cristaux liquides, composition pour la formation d'un film photopolymère, et composition pour la formation d'une couche de cristaux liquides

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08271900A (ja) * 1995-03-30 1996-10-18 Toshiba Corp 液晶表示装置
JP2002169161A (ja) * 2000-11-29 2002-06-14 Sharp Corp 液晶表示装置
JP2006267689A (ja) * 2005-03-24 2006-10-05 Sharp Corp 液晶表示装置の製造方法、及び液晶表示装置
JP2006343719A (ja) * 2005-06-08 2006-12-21 Au Optronics Corp 液晶ディスプレイパネルの製造方法
WO2010116565A1 (fr) * 2009-04-08 2010-10-14 シャープ株式会社 Dispositif d'affichage à cristaux liquides, procédé pour fabriquer un dispositif d'affichage à cristaux liquides, composition pour la formation d'un film photopolymère, et composition pour la formation d'une couche de cristaux liquides

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103626660A (zh) * 2012-08-23 2014-03-12 奇美电子股份有限公司 用于液晶层或配向层的感旋光性单体、使用其的液晶显示面板及其制作方法

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