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WO2019239794A1 - Panneau à cristaux liquides et dispositif d'affichage à cristaux liquides - Google Patents

Panneau à cristaux liquides et dispositif d'affichage à cristaux liquides Download PDF

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Publication number
WO2019239794A1
WO2019239794A1 PCT/JP2019/019813 JP2019019813W WO2019239794A1 WO 2019239794 A1 WO2019239794 A1 WO 2019239794A1 JP 2019019813 W JP2019019813 W JP 2019019813W WO 2019239794 A1 WO2019239794 A1 WO 2019239794A1
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WIPO (PCT)
Prior art keywords
liquid crystal
polarizer
anisotropic element
optically anisotropic
retardation
Prior art date
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Ceased
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PCT/JP2019/019813
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English (en)
Japanese (ja)
Inventor
林　大輔
草平 有賀
敏行 飯田
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Nitto Denko Corp
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Nitto Denko Corp
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Priority to KR1020217000386A priority Critical patent/KR102455388B1/ko
Priority to CN202310842279.7A priority patent/CN116819830B/zh
Priority to CN201980039432.4A priority patent/CN112313570B/zh
Publication of WO2019239794A1 publication Critical patent/WO2019239794A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/133528—Polarisers
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/13363—Birefringent elements, e.g. for optical compensation

Definitions

  • the present invention relates to a liquid crystal panel including an optically anisotropic element between a liquid crystal cell and a polarizer.
  • the present invention also relates to a liquid crystal display device using the liquid crystal panel.
  • the liquid crystal panel includes a liquid crystal cell between a pair of polarizers.
  • a liquid crystal cell includes a liquid crystal layer between a pair of substrates.
  • a color filter is provided on a substrate (color filter substrate) disposed on the viewing side of the liquid crystal layer and disposed on the light source side.
  • a pixel electrode, a TFT element, and the like are provided on a substrate (TFT substrate).
  • liquid crystal molecules are homogeneously aligned in a direction substantially parallel to the substrate surface in the absence of an electric field, and the liquid crystal molecules are aligned in a plane parallel to the substrate surface by applying a lateral electric field. It is rotated to control light transmission (white display) and shielding (black display).
  • IPS in-plane switching
  • a horizontal electric field type liquid crystal panel in which liquid crystal molecules are homogeneously aligned in an electric fieldless state is excellent in viewing angle characteristics.
  • the IPS liquid crystal display device includes an alignment direction of liquid crystal molecules in an electric field-free state of the liquid crystal cell (hereinafter sometimes referred to as “initial alignment direction”), and an absorption axis of a polarizer disposed on the front and back of the liquid crystal cell. Based on the relationship with the direction, it is roughly divided into an O mode and an E mode. In the O mode, the absorption axis direction of the polarizer disposed on the light source side of the liquid crystal cell and the initial alignment direction of the liquid crystal are parallel. In the E mode, the absorption axis direction of the polarizer disposed on the light source side of the liquid crystal cell is orthogonal to the initial alignment direction of the liquid crystal.
  • the IPS liquid crystal display device has a light leakage of black display when viewed from an oblique direction at angles of 45 degrees (azimuth angles of 45 degrees, 135 degrees, 225 degrees, and 315 degrees) with respect to the absorption axis of the polarizer. It is large and tends to cause a decrease in contrast and color shift. This light leakage is attributed to the fact that the angle formed by the “apparent absorption axis direction” of the polarizers arranged on the front and back of the liquid crystal cell deviates from 90 ° when viewed from an oblique direction.
  • Patent Document 1 proposes that an optically anisotropic element having a refractive index anisotropy of nx> nz> ny is disposed between a liquid crystal cell and one polarizer.
  • nx is the refractive index in the in-plane slow axis direction
  • ny is the refractive index in the in-plane fast axis direction
  • nz is the refractive index in the thickness direction (normal direction).
  • the retardation of the optically anisotropic element varies depending on the wavelength.
  • optical design is performed so that light leakage of green light (having a wavelength of about 550 nm) with high relative visibility is reduced. Therefore, in order to compensate for the apparent axial angle deviation of the polarizer, an optically anisotropic element having a retardation at a wavelength of 550 nm of about 275 nm may be used.
  • the characteristics of other optical elements can also cause light leakage during black display.
  • Patent Document 2 in consideration of the birefringence of a triacetyl cellulose (TAC) film provided as a protective film on the surface of the polarizer on the liquid crystal cell side, the optical characteristics of the optical anisotropic element for optical compensation are disclosed. It has been proposed to adjust.
  • Patent Document 3 it is proposed to use a low birefringence film such as a norbornene-based resin film as a protective film provided on the surface of a polarizer.
  • JP-A-4-371903 JP 2001-258041 A Japanese Patent Laid-Open No. 2004-4641
  • the color filter provided on the substrate of the liquid crystal cell has an in-plane retardation of approximately 0, but has a retardation of several nm to several tens of nm in the thickness direction.
  • the optical compensation of the liquid crystal panel is optimized for green light (having a wavelength of about 550 nm) with high specific visibility. Therefore, at the time of black display, light having a wavelength with a large optical design deviation from the optimum value leaks, and the screen is colored and visually recognized. Due to the optical design, it is difficult to make the hue when viewed from an oblique direction completely neutral, so when displaying black, the screen is visually colored slightly depending on the wavelength of the light that caused light leakage. . Since blue (near wavelength 450 nm) has a lower relative visibility than red (near wavelength 650 nm), the hue of black display tends to be preferred to be blue.
  • the optical anisotropic element is designed so as to minimize the green light leakage in consideration of the influence of the thickness direction retardation of the color filter.
  • red light leaks greatly and a black display screen when viewed from an oblique direction tends to be viewed with a red hue.
  • the absorption axis direction of the polarizer arranged on the light source side of the liquid crystal cell is orthogonal to the slow axis direction of the optically anisotropic element, the influence of the retardation in the thickness direction of the color filter is considered.
  • the red light leakage tends to be suppressed.
  • the absorption axis direction of the polarizer arranged on the light source side of the liquid crystal cell is parallel to the slow axis direction of the optically anisotropic element, consider the influence of retardation in the thickness direction of the color filter.
  • the present invention takes the influence of the color filter into account when viewed from an oblique direction.
  • An object of the present invention is to provide an image display device that reduces light leakage during black display, reduces red coloring during black display, and has excellent visibility.
  • the liquid crystal panel of the present invention includes a liquid crystal cell including a liquid crystal layer containing liquid crystal molecules that are homogeneously aligned in an electric field state, and a color filter disposed on the first main surface (viewing side) of the liquid crystal layer.
  • positioned at the 2nd main surface (light source side) of a liquid crystal cell are provided.
  • the absorption axis direction of the first polarizer and the absorption axis direction of the second polarizer are orthogonal to each other.
  • the color filter has at least a green transmission region and a red transmission region.
  • the green transmission region of the color filter preferably has a thickness direction retardation Ct 550 of 50 nm or less at a wavelength of 550 nm.
  • the red region of the color filter preferably has a thickness direction retardation Ct 650 at a wavelength of 650 nm of 50 nm or less.
  • Ct 550 and Ct 650 are both greater than zero.
  • Ct 550 and Ct 650 can be, for example, 1 nm or more, 3 nm or more, or 5 nm or more.
  • the liquid crystal panel of the present invention includes an optically anisotropic element disposed between the first polarizer and the second polarizer.
  • the slow axis direction of the optically anisotropic element is parallel to the absorption axis direction of the second polarizer.
  • the optically anisotropic element has a ratio Rt 650 / Re 650 of the front retardation Re 650 and the thickness direction retardation Rt 650 at a wavelength of 650 nm of 0.2 to 0.8.
  • the thickness direction retardation Rt 650 (nm) at a wavelength of 650 nm of the optical anisotropic element and the thickness direction retardation Ct 650 (nm) at a wavelength of 650 nm of the red transmission region of the color filter are expressed by the following formula (1a) or (2a). It is preferable to satisfy. Rt 650 ⁇ 0.37 (Ct 650 ) +116 (1a) Rt 650 ⁇ ⁇ 0.44 (Ct 650 ) +116 (2a)
  • the liquid crystal panel of the first embodiment of the present invention is in the O mode, and the alignment direction (initial alignment direction) of the liquid crystal molecules in the non-electric field state of the liquid crystal cell is parallel to the absorption axis direction of the second polarizer.
  • an optically anisotropic element is disposed between the liquid crystal cell and the first polarizer, that is, on the viewing side of the liquid crystal cell.
  • the thickness direction retardation Rt 550 (nm) at a wavelength of 550 nm of the optical anisotropic element and the thickness direction retardation Ct 550 (nm) at a wavelength of 550 nm of the green transmission region of the color filter are expressed by the following formula (3a ) Is preferably satisfied. 0.97 (Ct 550 ) + 73 ⁇ Rt 550 ⁇ 0.49 (Ct 550 ) +205 (3a)
  • the liquid crystal panel according to the second embodiment of the present invention is in the E mode, and the initial alignment direction of the liquid crystal molecules of the liquid crystal cell and the absorption axis direction of the second polarizer are orthogonal to each other.
  • an optically anisotropic element is disposed between the liquid crystal cell and the second polarizer, that is, on the light source side of the liquid crystal cell.
  • the thickness direction retardation Rt 550 (nm) at a wavelength of 550 nm of the optical anisotropic element and the thickness direction retardation Ct 550 (nm) at a wavelength of 550 nm of the green transmission region of the color filter are expressed by the following formula (8a). ) Is preferably satisfied. 0.69 (Ct 550 ) + 70 ⁇ Rt 550 ⁇ 1.35 (Ct 550 ) +200 (8a)
  • the liquid crystal display device of the present invention includes a light source disposed on the second main surface side of the liquid crystal panel.
  • a liquid crystal display device can be provided.
  • FIG. 1 is a conceptual diagram showing the arrangement of optical elements in the liquid crystal panel 101 of the first embodiment.
  • FIG. 2 is a schematic cross-sectional view of the liquid crystal display device 201 including the liquid crystal panel 101 and the light source 110.
  • FIG. 3 is a conceptual diagram showing the arrangement of optical elements in the liquid crystal panel 102 of the second embodiment.
  • FIG. 4 is a schematic cross-sectional view of the liquid crystal display device 202 including the liquid crystal panel 102 and the light source 110.
  • the liquid crystal panel includes a first polarizer 30 disposed on the first main surface (viewing side) of the liquid crystal cell 20 and a second polarizer 40 disposed on the second main surface (light source side) of the liquid crystal cell 20. .
  • the absorption axis direction 35 of the first polarizer 30 and the absorption axis direction 45 of the second polarizer 40 are orthogonal to each other.
  • the liquid crystal panel 101 and the liquid crystal display device 201 of the first embodiment are in the O mode, and the absorption axis direction 45 of the second polarizer 40 disposed on the light source 110 side of the liquid crystal cell 20 and the initial liquid crystal molecules in the liquid crystal layer 10.
  • the alignment direction 11 is parallel.
  • the liquid crystal panel 102 and the liquid crystal display device 202 of the second embodiment are in the E mode, and the absorption axis direction 45 of the second polarizer 40 disposed on the light source 110 side of the liquid crystal cell 20 and the initial liquid crystal molecules in the liquid crystal layer 10.
  • the orientation direction 11 is orthogonal.
  • the liquid crystal panel of the present invention includes an optically anisotropic element between the first polarizer 30 and the second polarizer 40.
  • the O-mode liquid crystal panel 101 of the first embodiment includes an optically anisotropic element 50 between the liquid crystal cell 20 and the first polarizer 30.
  • the E-mode liquid crystal panel 102 of the second embodiment includes an optically anisotropic element 60 between the liquid crystal cell 20 and the second polarizer 40.
  • the absorption axis direction 45 of the second polarizer 40 and the slow axis directions 53 and 63 of the optically anisotropic elements 50 and 60 are parallel.
  • the term “orthogonal” includes not only completely orthogonal but also substantially orthogonal, and the angle is generally in the range of 90 ⁇ 2 °, preferably 90 ⁇ 1. °, more preferably in the range of 90 ⁇ 0.5.
  • “parallel” includes not only completely parallel but also substantially parallel, and the angle is generally within ⁇ 2 °, preferably within ⁇ 1 °, more preferably Is within ⁇ 0.5 °.
  • the liquid crystal cell 20 includes the liquid crystal layer 10 between the first substrate 21 and the second substrate 25.
  • a color filter 22 is provided on the first substrate 21 (color filter substrate) disposed on the viewing side of the liquid crystal layer.
  • the color filter 22 has at least a green transmission region 22G and a red transmission region 22R.
  • the second substrate 25 (TFT substrate) disposed on the light source side of the liquid crystal layer 10 is provided with a switching element (generally a TFT element) for controlling the alignment direction of the liquid crystal.
  • a green filter having a relatively high transmittance with respect to light having a wavelength of about 500 to 600 nm is provided.
  • the green filter preferably has a maximum transmittance in the vicinity of a wavelength of 500 to 600 nm.
  • the transmittance at a wavelength of 550 nm in the green transmission region is, for example, 30% or more.
  • the transmittance at a wavelength of 450 nm in the green transmission region is preferably 10% or less.
  • the transmittance at a wavelength of 650 nm in the green transmission region is preferably 10% or less, and more preferably 5% or less.
  • the red transmission region 22R is provided with a red filter having a relatively high transmittance with respect to visible light having a wavelength longer than 600 nm.
  • the transmittance at a wavelength of 650 nm in the red transmission region is, for example, 30% or more.
  • the transmittance at a wavelength of 550 nm and the transmittance at a wavelength of 450 nm in the red transmission region are both preferably 10% or less, and more preferably 5% or less.
  • the color filter 22 may include a region other than the green transmission region 22G and the red transmission region 22R, and generally includes a blue transmission region 22B.
  • the blue transmission region 22B is provided with a blue filter having a relatively high transmittance with respect to visible light having a wavelength shorter than 500 nm.
  • the transmittance at a wavelength of 450 nm in the blue transmission region is, for example, 30% or more.
  • the transmittance at a wavelength of 550 nm and the transmittance at a wavelength of 650 nm in the blue transmission region are both preferably 10% or less, and more preferably 5% or less.
  • the color filter may further include a light transmission region having a relatively high light transmittance with respect to a specific wavelength region other than the above.
  • a black matrix is preferably provided at the boundary between adjacent transmission regions.
  • the liquid crystal layer 10 includes liquid crystal molecules that are homogeneously aligned in the absence of an electric field.
  • the homogeneously aligned liquid crystal molecules are those in which the alignment vectors of the liquid crystal molecules are aligned in parallel and uniformly with respect to the substrate plane.
  • the alignment vector of the liquid crystal molecules may be slightly inclined with respect to the substrate plane (pretilt).
  • the pretilt angle of the liquid crystal cell is generally 3 ° or less, preferably 1 ° or less, more preferably 0.5 ° or less.
  • liquid crystal cells containing liquid crystal molecules that are homogeneously aligned in an electroless state include an in-plane switching (IPS) mode, a fringe field switching (FFS) mode, and a ferroelectric liquid crystal (FLC) mode.
  • IPS in-plane switching
  • FFS fringe field switching
  • FLC ferroelectric liquid crystal
  • the liquid crystal molecule nematic liquid crystal, smectic liquid crystal, or the like is used. In general, nematic liquid crystal is used for IPS mode and FFS mode liquid crystal cells, and smectic liquid crystal is used for FLC mode liquid crystal cells.
  • the first polarizer 30 is disposed on the first main surface side of the liquid crystal cell 20, and the second polarizer 40 is disposed on the second main surface side.
  • a polarizer converts natural light or arbitrary polarized light into linearly polarized light.
  • Any appropriate polarizer may be adopted as the first polarizer 30 and the second polarizer 40 depending on the purpose.
  • dichroic substances such as iodine and dichroic dyes are adsorbed on hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and ethylene / vinyl acetate copolymer partially saponified films.
  • a polyene-based oriented film such as a uniaxially stretched product, a polyvinyl alcohol dehydrated product or a polyvinyl chloride dehydrochlorinated product.
  • a dichroic substance such as iodine or a dichroic dye is adsorbed on a polyvinyl alcohol film such as polyvinyl alcohol or partially formalized polyvinyl alcohol, and a predetermined amount is obtained.
  • a polyvinyl alcohol (PVA) polarizer oriented in the direction is preferably used.
  • a PVA polarizer can be obtained by subjecting a polyvinyl alcohol film to iodine staining and stretching.
  • a thin polarizer having a thickness of 10 ⁇ m or less can be used.
  • the thin polarizer are described in, for example, JP-A-51-069644, JP-A-2000-338329, WO2010 / 100917 pamphlet, Japanese Patent No. 4691205, Japanese Patent No. 4751481, and the like.
  • a thin polarizing film is obtained, for example, by a production method including a step of stretching a PVA-based resin layer and a stretching resin base material in the state of a laminate, and a step of iodine staining.
  • the in-plane refractive index nx in the slow axis direction, the in-plane refractive index ny in the fast axis direction, and the refractive index nz in the thickness direction satisfy nx>nz> ny. It is a retardation film.
  • the polarizers 30 and 40 disposed above and below the liquid crystal cell 20 are disposed so that the absorption axis directions 35 and 45 are orthogonal to each other. However, when the liquid crystal panel is viewed from an oblique direction, the polarizers 30 and 40 appear to be apparent. Since the angle formed by the absorption axis direction becomes larger than 90 ° (deviation from crossed Nicols occurs), light leakage occurs.
  • nx> nz> ny When a retardation film satisfying nx> nz> ny is disposed between the liquid crystal cell 20 and the polarizers 30 and 40 to compensate for the apparent axial deviation of the polarizer and the screen is viewed from an oblique direction. Light leakage can be reduced. In particular, the black luminance at 45 degrees (azimuth angles of 45 degrees, 135 degrees, 225 degrees, and 315 degrees) with respect to the absorption axis of the polarizer is reduced, and the contrast is improved.
  • the optical anisotropic element 50 is disposed between the liquid crystal cell 20 and the first polarizer 30 on the viewing side.
  • an optical anisotropic element 60 is disposed between the liquid crystal cell 20 and the second polarizer 40 on the light source side.
  • the front retardation Re 550 of the optically anisotropic elements 50 and 60 at a wavelength of 550 nm is preferably 150 to 400 nm, more preferably 180 to 370 nm, and further preferably 200 to 350 nm.
  • the thickness direction retardation Rt 550 of the optically anisotropic element at a wavelength of 550 nm is preferably 75 to 200 nm, more preferably 90 to 185 nm, and still more preferably 100 to 175 nm.
  • Rt (nx ⁇ nz) ⁇ d
  • the Nz coefficient is calculated based on the refractive index at a wavelength of 650 nm. That is, the Nz coefficient is a ratio Rt 650 / Re 650 between the front retardation Re 650 and the thickness direction retardation Rt 650 at a wavelength of 650 nm. Therefore, the optically anisotropic element preferably has Rt 650 / Re 650 of 0.2 to 0.8.
  • the Nz coefficient calculated based on the refractive index at a wavelength of 550 nm and the Nz coefficient calculated based on the refractive index at a wavelength of 650 nm are substantially the same.
  • the Nz coefficient of the optically anisotropic element is more preferably 0.3 to 0.7, and further preferably 0.4 to 0.6. As the Nz coefficient is closer to 0.5, light leakage tends to decrease in a wide viewing angle range.
  • the materials constituting the optically anisotropic element include polycarbonate resins, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polyarylate resins, sulfone resins such as polysulfone and polyethersulfone, and sulfides such as polyphenylene sulfide. Resin, polyimide resin, cyclic polyolefin (polynorbornene) resin, polyamide resin, polyolefin resin such as polyethylene and polypropylene, and cellulose esters.
  • a liquid crystal material can also be used as the material of the optically anisotropic element.
  • an optically anisotropic element (retardation film) can be produced by stretching or shrinking a polymer film in at least one direction to enhance molecular orientation in a predetermined direction. While the polymer film and the heat-shrinkable film are laminated, the film is shrunk in the direction perpendicular to the stretching direction by using the shrinkage force of the heat-shrinkable film while stretching in one direction, thereby obtaining nx> nz> An optically anisotropic element having a refractive index anisotropy of ny is obtained.
  • the thickness of the optically anisotropic element can be appropriately selected depending on the material constituting the optically anisotropic element. When a polymer material is used, the thickness of the optically anisotropic element is generally about 3 ⁇ m to 200 ⁇ m. When a liquid crystal material is used, the thickness of the optically anisotropic element (the thickness of the liquid crystal layer) is generally about 0.1 ⁇ m to 20 ⁇ m.
  • the optically anisotropic element only needs to have predetermined Re and Rt, and the material, thickness, and manufacturing method of the optically anisotropic element are not limited to the above.
  • Optical compensation principle by optical anisotropic element In the present invention, by setting the optical characteristics of the optical anisotropic element in accordance with the birefringence of the color filter, both the apparent axial deviation of the polarizer and the influence of the birefringence of the color filter are optically affected. Thus, a liquid crystal display device with little light leakage when viewed from an oblique direction and a neutral hue of black display can be obtained. Specifically, the thickness direction retardation Ct 550 at a wavelength of 550 nm in the green transmission region 22G of the color filter 22 and the thickness direction retardation Rt 550 at a wavelength of 550 nm of the optically anisotropic elements 50 and 60 satisfy a predetermined relationship.
  • a thickness direction retardation Ct 650 having a wavelength of 650 nm in the red transmission region 22R of the color filter 22 and a thickness direction retardation Rt 650 having a wavelength of 650 nm of the optically anisotropic elements 50 and 60 satisfy a predetermined relationship.
  • the optical characteristics of the optical anisotropic element are set.
  • FIG. 5 illustrates how the optically anisotropic element 50 compensates for the apparent axial displacement of the polarizers 30 and 40 in the O-mode liquid crystal panel 101 shown in FIG. 1 using Poincare spheres. Yes.
  • the light transmitted through the light source side polarizer 40 is linearly polarized light.
  • the light transmitted through the polarizer is represented by a point P 0 on the equator of the Poincare sphere. Since the absorption axis direction 35 of the viewing side polarizer 30 and the absorption axis direction 45 of the light source side polarizer 40 are orthogonal to each other, the light transmitted through the viewing side polarizer 30 is a point P 1 on the equator of the Poincare sphere. expressed.
  • the polarization state of the light transmitted through the polarizer 40 does not change after transmission through the liquid crystal cell. That is, the polarization state of the light transmitted through the liquid crystal cell does not move from the point P 0 on the Poincare sphere. Since the light P 0 transmitted through the liquid crystal cell 20 and the light P 1 transmitted through the viewing side polarizer 30 are linearly polarized light, all of the light transmitted through the liquid crystal cell 20 is absorbed by the viewing side polarizer 30. Therefore, black display can be realized.
  • the apparent axis of the light source side polarizer 40 The direction moves from P 0 to P ′ 0 , and the apparent axial direction of the viewing side polarizer 30 moves from P 1 to P ′ 1 .
  • the polar angle ⁇ increases, the change in the apparent axial direction of the polarizer increases.
  • the polarization state of the light transmitted through the liquid crystal cell 20 is orthogonal to the light P ′ 1 transmitted through the viewing side polarizer 30. it is necessary to linearly polarized light P a.
  • the absorption axis direction 45 of the light source side polarizer 40 and the initial alignment direction 11 of the liquid crystal cell 20 are parallel to each other, an apparent initial stage when viewed from an oblique direction.
  • the alignment direction 11 moves in the same manner as the absorption axis direction 45 of the light source side polarizer. For this reason, the polarization state of the light transmitted through the polarizer 40 does not change after passing through the liquid crystal cell, and does not move from the point P ′ 0 on the Poincare sphere.
  • the light transmitted through the liquid crystal cell 20 enters the optical anisotropic element 50.
  • the optically anisotropic element 50 having an Nz coefficient of 0.5 does not change the apparent optical axis direction when viewed from any angle, and has a slow axis on the line connecting P 0 and P 1. .
  • the front retardation (retardation with respect to light in the normal direction) Re of the optically anisotropic element 50 is 1 ⁇ 2 of the wavelength ⁇ .
  • the linearly polarized light P A since the viewing side polarizer 30 is linearly polarized perpendicular to the light P '1 that transmits light P A the polarization state is changed by the optical anisotropic device 50 is visible It is absorbed by the side polarizer 30 and a black display can be realized.
  • the initial alignment direction 11 of the liquid crystal molecules in the liquid crystal cell 20 is orthogonal to the absorption axis direction 45 of the light source side polarizer 40.
  • the optically anisotropic element 60 is disposed between the light source side polarizer 40 and the liquid crystal cell 20, and the linearly polarized light P ′ 0 transmitted through the light source side polarizer 40 is reflected on the Poincare sphere by the optical anisotropic element 60. It is moved to the point P a.
  • the linearly polarized light P '0 from the light source side polarizer 40 by entering the liquid crystal cell 20 after it is converted to linearly polarized light P A by the optical anisotropic device 60, the light transmitted through the liquid crystal cell polarization state for not change from P a, is absorbed by the viewing side polarizer 30, it is possible to realize a black display.
  • the optical design of the optically anisotropic element is an angle (parallel) between the optical axis direction of the optically anisotropic element and the optical axis direction of the polarizer. And the angle between the initial alignment direction of the liquid crystal cell and the optical axis direction of the polarizer (whether the mode is O mode or E mode).
  • the color filter 22 provided on the viewing side of the liquid crystal layer 10 in the liquid crystal cell 20 has an in-plane retardation of approximately 0, but has a retardation of several nm to several tens of nm in the thickness direction. ing.
  • the thickness direction retardation with respect to light having a wavelength of about 550 nm, which has the highest transmittance affects the visibility.
  • the retardation in the thickness direction with respect to light having a high transmittance near the wavelength of 650 nm affects the visibility.
  • the thickness direction retardation Ct 550 having a wavelength of 550 nm is used for the green transmission region (green color filter), and the red transmission region (red color filter) is used.
  • the thickness direction retardation Ct 650 having a wavelength of 650 nm is appropriately evaluated using a thickness direction retardation Ct 650 having a wavelength of 650 nm.
  • the thickness direction retardation of the color filter is preferably small.
  • the thickness direction retardation Ct 550 at a wavelength of 550 nm in the green transmission region is preferably 50 nm or less, more preferably 40 nm or less, still more preferably 35 nm or less, and particularly preferably 30 nm or less.
  • the thickness direction retardation Ct 650 in the red region of the color filter at a wavelength of 650 nm is preferably 50 nm or less, more preferably 40 nm or less, still more preferably 35 nm or less, and particularly preferably 30 nm or less.
  • Ct 550 and Ct 650 are greater than zero.
  • Ct 550 and Ct 650 can be, for example, 1 nm or more, 3 nm or more, or 5 nm or more.
  • the light transmitted through the liquid crystal layer enters the color filter 22.
  • Light oblique direction due to the influence of the thickness-direction retardation of the negative C plate, the polarization state is changed, then south from the point P '0 along the meridian on the Poincare sphere, moves to point P C.
  • the phase difference of the optically anisotropic element is ⁇ (when rotated 180 ° on the Poincare sphere)
  • the polarization state of the light transmitted through the optically anisotropic element is as shown in FIG. 8A. represented by P 'a, located northern hemisphere of the Poincare sphere.
  • the light after passing through the optical anisotropic device 50 in order to linearly polarized light represented by point P A on the equator, larger than 180 ° the rotation angle on the Poincare sphere by the optical anisotropic element
  • the optical anisotropic element There is a need. That is, in consideration of the influence of birefringence of the color filter, in the O-mode liquid crystal panel 101 shown in FIG. 1, in order to make the light after passing through the optical anisotropic element 50 linearly polarized light, the optical anisotropic element
  • the phase difference of 50 needs to be larger than ⁇ .
  • FIG. 8B shows a state of optical compensation in the O-mode liquid crystal panel 106 of FIG. 6 in which the absorption axis direction 45 of the second polarizer 40 and the slow axis direction 53 of the optical anisotropic element 50 are orthogonal to each other.
  • the phase difference of the optically anisotropic element is a [pi, when is 180 ° rotated counterclockwise on the Poincare sphere from the point P C, reaching past the equator northern hemisphere point P 'A.
  • the light after passing through the optical anisotropic device 50, in order to linearly polarized light represented by point P A on the equator is smaller than 180 ° rotation angle on the Poincare sphere by the optical anisotropic element
  • the optical anisotropic element It is necessary to make the phase difference of 50 smaller than ⁇ .
  • FIG. 9A shows the state of optical compensation in the E-mode liquid crystal panel 107 of FIG. 7 in which the absorption axis direction 45 of the second polarizer 40 and the slow axis direction 63 of the optically anisotropic element 60 are orthogonal to each other.
  • the polarization state is changed, south along the meridian on the Poincare sphere To do.
  • linearly polarized light P A light after passing through the color filter, in order to absorb the viewing side polarizer 30 is required to a liquid crystal cell light P L after transmission is positioned northern hemisphere on the Poincare sphere.
  • the phase difference of the optically anisotropic element [pi, the linearly polarized light P '0 passing through the light source side polarizing element, the optical anisotropic element to a point P A on the Poincaré sphere If is, the polarization state of light transmitted through the liquid crystal cell does not change from P a. However, the light after passing through the liquid crystal cell goes south along the meridian on the Poincare sphere due to the influence of the thickness direction retardation of the color filter, so the light after passing through the color filter becomes elliptically polarized light located in the southern hemisphere. The light that is not absorbed by the viewing side polarizer 30 is viewed as light leakage.
  • the phase difference of the optically anisotropic element 60 is made smaller than ⁇ (the rotation angle on the Poincare sphere by the optically anisotropic element is 180 °). Therefore, appropriate optical compensation becomes possible.
  • the polarization state of the light phase difference has passed through the small optical anisotropic device than ⁇ is expressed in terms P R on the southern hemisphere of the Poincare sphere.
  • the polarization state of the light transmitted through the liquid crystal layer 10 is Poincare represented by the point P L above the northern hemisphere of the sphere.
  • the liquid crystal cell light P L after transmission is transmitted through the color filter 22, and south along the meridian on the Poincare sphere, and reaches the point P A on the equator. Therefore, the light P A after passing through the color filter is adequately absorbed by the viewing side polarizer 30, light leakage can be prevented.
  • FIG. 9B shows a state of optical compensation in the E-mode liquid crystal panel 102 of FIG. 3 in which the absorption axis direction 45 of the second polarizer 40 and the slow axis direction 63 of the optical anisotropic element 60 are parallel. .
  • the phase difference of the optical anisotropic element 60 is larger than ⁇ (the rotation angle on the Poincare sphere by the optical anisotropic element is larger than 180 °)
  • the optical anisotropic element is transmitted.
  • the polarization state of the light is located at a point P R on the southern hemisphere of the Poincare sphere. Thereafter, as in the case of FIG.
  • the light passes through the liquid crystal layer 10 to move to the point P L on the northern hemisphere, and passes through the color filter 22 to reach the point P A on the equator.
  • light P a after passing through the filter is properly absorbed by the viewing side polarizer 30.
  • the optical anisotropic element has a thickness depending on the thickness direction retardation of the color filter. It is necessary to adjust the phase difference.
  • the absorption axis direction of the light source side polarizer and the slow axis direction of the optically anisotropic element are parallel, that is, the O-mode liquid crystal panel 101 (see FIG. 8A) shown in FIG. 1 and the E shown in FIG.
  • the phase difference of the optically anisotropic element needs to be larger than ⁇ (retardation larger than ⁇ / 2).
  • optical design of optically anisotropic elements below, the preferable optical characteristic of the optical anisotropic element according to the thickness direction retardation of the color filter of a liquid crystal cell is demonstrated with the examination result by optical simulation.
  • a liquid crystal display simulator “LCD MASTER Ver.8.1.0.3” manufactured by Shintech Co., Ltd. is used, and an extension function of LCD Master is used, with an azimuth angle of 45 ° and a polar angle of 60 °.
  • the luminance of black display and the chromaticity (u ′, v ′) in the CIE 1976 color space for black display were obtained.
  • the simulation of the O-mode liquid crystal display device as shown in FIG. 2, from the light source 110 side, the light source side polarizer 40, the IPS liquid crystal cell 20 including the color filter 22 on the viewing side of the liquid crystal layer 10, and the optical anisotropic element 50 and the viewing-side polarizer 30 stacked in order were used as a simulation model.
  • an IPS liquid crystal cell including a color filter 22 on the viewing side of the light source side polarizer 40, the optically anisotropic element 60, and the liquid crystal layer 10 from the light source 110 side. 20 and the viewing side polarizer 30 were laminated in order as a simulation model.
  • the front retardation of the liquid crystal layer of the IPS liquid crystal cell was 339 nm, and the pretilt angle was 0 °.
  • the Nz coefficient was 0.5
  • Rt 650 was changed to various values.
  • the thickness direction retardation Ct 550 at a wavelength of 550 nm in the green transmission region and the thickness direction retardation Ct 650 at a wavelength of 650 nm in the red transmission region were changed in increments of 5 nm in the range of 0 to 60 nm.
  • FIGS. 10A and 10B show the chromaticity of black display when Ct 650 and Rt 650 are changed to various values in the O-mode liquid crystal panel.
  • FIG. 11A and FIG. 11B show the chromaticity of black display when Ct 650 and Rt 650 are changed to various values in the E-mode liquid crystal panel.
  • FIG. 10A shows a liquid crystal panel 101 in which the absorption axis direction 45 of the light source side polarizer 40 and the slow axis direction 53 of the optical anisotropic element 50 are parallel as shown in FIG. 1 (see FIG. 8A for the principle of optical compensation). It is a simulation result.
  • FIG. 10B shows a simulation of the liquid crystal panel 106 (see FIG. 8B for the principle of optical compensation) in which the absorption axis direction 45 of the light source side polarizer 40 and the slow axis direction 53 of the optical anisotropic element 50 are orthogonal to each other as shown in FIG. It is a result.
  • FIG. 11A shows a simulation of the liquid crystal panel 107 (see FIG.
  • 11B shows a liquid crystal panel 102 (see FIG. 9B for the optical compensation principle) in which the absorption axis direction 45 of the light source side polarizer 40 and the slow axis direction 63 of the optical anisotropic element 60 are parallel to each other as shown in FIG. It is a simulation result.
  • any of the O mode liquid crystal panel 106 shown in FIG. 6 and the E mode liquid crystal panel 107 shown in FIG. 5 it can be seen that the black display screen is not remarkably colored when viewed from an oblique direction.
  • FIG. 12 is a graph plotting conditions under which the chromaticity of black display becomes a predetermined value based on the simulation result of the O-mode liquid crystal panel 101 shown in FIG.
  • the horizontal axis represents the thickness direction retardation Ct 650 at a wavelength of 650 nm in the red transmission region of the color filter, and the vertical axis represents the thickness direction retardation Rt 650 at a wavelength of 650 nm of the optical anisotropic element.
  • each Ct 650 points where the chromaticity u ′ of black display is 0.35 in the directions of azimuth angle 45 ° and polar angle 60 ° are indicated by black circles and black triangles. .
  • u ′ exceeds 0.35 and the black display is colored red and viewed.
  • u ′ is less than 0.35, and the red coloration of black display is suppressed.
  • the straight line in the graph is represented by the following formulas (1) and (2).
  • Rt 650 0.37 (Ct 650 ) +116 (1)
  • Rt 650 ⁇ 0.44 (Ct 650 ) +116 (2)
  • the thickness direction retardation Ct 650 at a wavelength of 650 nm in the red transmission region 22R of the color filter 22 and the thickness direction retardation Rt 650 at a wavelength of 650 nm of the optical anisotropic element 50 are expressed by the following formula (1a) or (2a).
  • u ′ is 0.35 or less, and a black display with reduced redness can be realized.
  • a white circle and a white triangle in FIG. 12 indicate points where the chromaticity u ′ for black display is 0.314.
  • u ′ is 0.314 to 0.35, and when it is above the white circle, u ′ Is less than 0.314.
  • u ′ is 0.314 to 0.35, and is below the white triangle mark.
  • U ′ is smaller than 0.314.
  • C 1 in the formula (1c) 116 nm
  • C 2 in the formula (2c) 116 nm.
  • C 1 may be set larger and C 2 may be set smaller.
  • C 1 in formula (1c) can be any number greater than or equal to 116.
  • C 1 may be 116 nm, 121 nm, 124 nm, 126 nm, 128 nm, 130 nm, 132 nm, 134 nm, 136 nm, 138 nm, or 140 nm.
  • C 2 in formula (2c) can be any number below 116.
  • C 2 may be 116 nm, 112 nm, 108 nm, 105 nm, 102 nm, 100 nm, 98 nm, 96 nm, 94 nm, 92 nm, or 90 nm.
  • Rt 650 at a wavelength of 650 nm of the optical anisotropic element 50 satisfies the above formula (1c) or (2c).
  • the upper limit or lower limit is not particularly limited. However, as will be described later, in consideration of the range of Rt 550 for reducing the black luminance and the retardation wavelength dispersion Rt 650 / Rt 550 of the optically anisotropic element 50, the upper limit and the lower limit of Rt 650 are naturally determined. It is done.
  • FIG. 13 is a graph plotting conditions under which the black luminance becomes a predetermined value based on the simulation result of the O-mode liquid crystal panel 101 shown in FIG.
  • the horizontal axis represents the thickness direction retardation Ct 550 at a wavelength of 550 nm in the green transmission region of the color filter
  • the vertical axis represents the thickness direction retardation Rt 550 at a wavelength of 550 nm of the optical anisotropic element.
  • the black luminance in the direction of the azimuth angle of 45 ° and the polar angle of 60 ° has the same Ct 550 and is half that of a liquid crystal display device using no optical anisotropic element.
  • Rt 550 is between a black circle and a black triangle, the black luminance when viewed from an oblique direction is less than half compared to the case where no optically anisotropic element is provided. Reduced.
  • the boundary of the region where the black luminance is 1 ⁇ 2 compared to the case where no optically anisotropic element is used can be approximated by a straight line on both the upper limit side and the lower limit side.
  • the straight line in the graph is represented by the following formulas (3) and (4).
  • Rt 550 0.97 (Ct 550 ) +73
  • Rt 550 0.49 (Ct 550 ) +205 (4)
  • the thickness direction retardation Ct 550 of the wavelength 550 nm in the green transmission region 22G of the color filter 22 and the thickness direction retardation Rt 550 of the optical anisotropic element 50 at the wavelength 550 nm satisfy the following formula (3a).
  • the black luminance in the oblique direction is 1 ⁇ 2 or less. 0.97 (Ct 550 ) + 73 ⁇ Rt 550 ⁇ 0.49 (Ct 550 ) +205 (3a)
  • a white circle and a white triangle in FIG. 13 indicate that the black luminance is 1/5 of the black luminance of a liquid crystal display device that does not use an optically anisotropic element.
  • Rt 550 is between the white circle and the white triangle, the black luminance is reduced to 1/5 or less as compared with the case where no optically anisotropic element is provided.
  • C 3 in formula (3c) can be any number greater than or equal to 73.
  • C 3 may be 73 nm, 88 nm, 98 nm, 108 nm, 113 nm, 118 nm, 123 nm, or 128 nm.
  • C 4 in formula (3c) can be any number below 205.
  • C 4 may be 205 nm, 190 nm, 180 nm, 173 nm, 168 nm, 163 nm, 158 nm, 153 nm, or 148 nm.
  • the thickness-direction retardation Ct 550 of the color filter is large, in Figure 8A, which corresponds to the distance P '0 and Pc is large (high latitude of P C). Higher latitude of P C is out of the large equator, the light after passing through the optical anisotropic device 50 to move on the equator of the Poincare sphere, it is necessary to increase the phase difference of the optically anisotropic element . Therefore, as shown in FIG. 13, as Ct 550 is larger, Rt 550 needs to be increased in order to reduce the black luminance.
  • Rt 550 of the optical anisotropic element is set so as to satisfy the above formula (3c) according to the thickness direction retardation Ct 550 of the color filter.
  • Rt 650 of the optically anisotropic element may be set so as to satisfy the above formula (1c) or (2c).
  • Rt 550 and Rt 650 cannot be set individually, and Rt 650 / Rt 550 is a constant value according to the wavelength dispersion of retardation of the optical anisotropic element.
  • the thickness direction retardation Ct 550 in the green transmission region of the color filter is 10 nm and the Rt 550 of the optical anisotropic element is 130 nm, the black luminance when viewed from an oblique direction is small, and the high contrast Display is feasible.
  • the Rth of the two is different, and Ct 650 of the red color filter may be larger than Ct 550 of the green color filter.
  • Ct 650 of the red color filter may be larger than Ct 550 of the green color filter.
  • the chromaticity u ′ of black display increases even when the optical anisotropic element is optically designed to reduce the black luminance.
  • the black display may be colored red.
  • the above formula (3c) is satisfied (however, , C 3 is 73 nm or more, C 4 is 205 nm or less), and satisfies the above formula (1c) or (2c) (where C 1 is 116 nm or more and C 2 is 116 nm or less)
  • the thickness direction retardation of the optically anisotropic element may be set.
  • the wavelength dispersion Rt 650 / Rt 550 of the retardation in the thickness direction of the retardation film is generally substantially equal to the wavelength dispersion Re 650 / Re 550 of the front retardation and is in the range of 0.8 to 1.2.
  • Ct 650 is 10 nm or more
  • Rt 550 satisfies the formula (3c)
  • Rt 650 rarely satisfies the formula (2c). Therefore, it is preferable to set the retardation of the optical anisotropic element so that Rt 550 satisfies the above formula (3c) and Rt 650 satisfies the above formula (1c).
  • the front retardation Re 550 and Re 650 of the optically anisotropic element 50 may be set so that Rt 550 and Rt 650 are in the above range.
  • the front retardations Re 550 and Re 650 are determined according to the thickness direction retardations Rt 550 and Rt 650 of the anisotropic element and the Nz coefficient.
  • the front retardation Re 650 of the optically anisotropic element 50 at a wavelength of 650 nm is preferably about twice that of Rt 650 . Therefore, Re 650 preferably satisfies the following formula (1d) or (2d). Re 650 ⁇ 0.74 (Ct 650 ) + C 11 (1d) Re 650 ⁇ ⁇ 0.88 (Ct 650 ) + C 12 (2d)
  • C 11 is twice the C 1, in particular C 11 is more than 232 nm.
  • C 11 may be 232 nm, 236 nm, 242 nm, 248 nm, 252 nm, 256 nm, 260 nm, 264 nm, 268 nm, 272 nm, 276 nm, or 280 nm.
  • C 12 is twice the C 2, in particular C 12 is less than 232 nm.
  • C 12 may be 232 nm, 224 nm, 216 nm, 210 nm, 204 nm, 200 nm, 196 nm, 192 nm, 188 nm, 184 nm, or 180 nm.
  • Re 650 of the optically anisotropic element 50 preferably satisfies the above formula (1d).
  • the front retardation Re 550 of the optically anisotropic element 50 at a wavelength of 550 nm is preferably about twice that of Rt 550 . Therefore, Re 550 preferably satisfies the following formula (3d). 1.94 (Ct 550 ) + C 13 ⁇ Re 550 ⁇ 0.98 (Ct 550 ) + C 14 (3d)
  • C 13 is twice the C 3, in particular C 13 is more than 146 nm.
  • C 13 may be 145 nm, 175 nm, 185 nm, 215 nm, 225 nm, 235 nm, 245 nm, or 255 nm.
  • C 14 is twice the C 4, in particular C 14 is 410nm or less.
  • C 14 may be 410 nm, 380 nm, 360 nm, 345 nm, 335 nm, 325 nm, 315 nm, 305 nm, or 295 nm.
  • FIG. 14 is a graph plotting conditions under which the chromaticity of black display becomes a predetermined value based on the simulation result of the E-mode liquid crystal panel 102 shown in FIG.
  • the black display chromaticity u ′ in the direction of azimuth angle 45 ° and polar angle 60 ° is 0.35, indicated by black circles and black triangles.
  • the point at which the chromaticity u ′ of the image becomes 0.314 is indicated by a white circle and a white triangle.
  • the thickness direction retardation Ct 650 having a wavelength of 650 nm in the red transmission region 22R of the color filter 22 and the thickness direction retardation Rt 650 of the optical anisotropic element 50 having a wavelength of 650 nm are expressed by the following formula (6a). ) Or (7a), u ′ is 0.35 or less, and black display with reduced redness can be realized.
  • Expression (6) is the same as Expression (1) regarding the O-mode liquid crystal panel 101.
  • Expression (7) is expressed by a straight line parallel to Expression (2) regarding the O-mode liquid crystal panel 101.
  • the straight line of Formula (2) is shown by the dotted line for reference.
  • C 6 in formula (6c) can be any number greater than or equal to 116.
  • C 6 may be a numerical value equivalent to C 1 described above, and C 6 may be 116 nm, 118 nm, 121 nm, 124 nm, 126 nm, 128 nm, 130 nm, 132 nm, 134 nm, 136 nm, 138 nm, or 140 nm.
  • C 7 in formula (7c) can be any number up to 120.
  • C 7 It may be a numerical value equivalent to C 2 described above, and may be 121 nm, 116 nm, 112 nm, 108 nm, 105 nm, 102 nm, 100 nm, 98 nm, 96 nm, 94 nm, 92 nm, or 90 nm.
  • Rt 650 of the optically anisotropic element 60 satisfies the above formula (6c).
  • Rt 650 at a wavelength of 650 nm of the optical anisotropic element 60 satisfies the above formula (6c) or (7c).
  • the upper limit or lower limit is not particularly limited. However, as described above with respect to the first embodiment, in consideration of the range of Rt 550 for reducing the black luminance and the wavelength dispersion Rt 650 / Rt 550 of the retardation of the optical anisotropic element 60, the upper limit of Rt 650 and The lower limit is determined by itself.
  • FIG. 15 is a graph plotting conditions under which the black luminance becomes a predetermined value based on the simulation result of the E-mode liquid crystal panel 102 shown in FIG.
  • the black luminance in the direction of azimuth angle 45 ° and polar angle 60 ° is half that of a liquid crystal display device that does not use an optically anisotropic element.
  • a point where the black luminance is 1/5 of a liquid crystal display device using no optically anisotropic element is indicated by a white circle and a white triangle.
  • the thickness direction retardation Ct 550 of the wavelength 550 nm in the green transmission region 22G of the color filter 22 and the thickness direction retardation Rt 550 of the optical anisotropic element 50 at the wavelength 550 nm are expressed by the following formula (8a).
  • the black luminance is 1 ⁇ 2 or less compared to the case where no optically anisotropic element is used. 0.69 (Ct 550 ) + 70 ⁇ Rt 550 ⁇ 1.35 (Ct 550 ) +200 (8a)
  • C 8 should be set large and C 9 should be set small.
  • C 8 in the formula (8c) may be any number of 70 or more.
  • C 8 may be 78 nm, 88 nm, 98 nm, 108 nm, 113 nm, 118 nm, 123 nm, or 128 nm.
  • C 9 in formula (8c) can be any number up to 200.
  • C 9 may be 200 nm, 190 nm, 180 nm, 173 nm, 168 nm, 163 nm, 158 nm, 153 nm, or 148 nm.
  • the above formula (8c) is satisfied according to the thickness direction retardation Ct 550 of the color filter.
  • the front retardations Re 550 and Re 650 of the optically anisotropic element 60 may be set so that Rt 550 and Rt 650 are in the above range.
  • the front retardation Re 650 of the optically anisotropic element 60 at a wavelength of 650 nm is preferably about twice that of Rt 650 . Therefore, Re 650 preferably satisfies the following formula (6d) or (7d). Re 650 ⁇ 0.74 (Ct 650 ) + C 16 (6d) Re 650 ⁇ ⁇ 0.88 (Ct 650 ) + C 17 (7d)
  • C 16 is twice the C 6, in particular C 16 is more than 232 nm.
  • C 16 may be 232 nm, 236 nm, 242 nm, 248 nm, 252 nm, 256 nm, 260 nm, 264 nm, 268 nm, 272 nm, 276 nm, or 280 nm.
  • C 17 is twice the C 7, in particular C 17 is less than 240 nm.
  • C 12 may be 240 nm, 232 nm, 224 nm, 216 nm, 210 nm, 204 nm, 200 nm, 196 nm, 192 nm, 188 nm, 184 nm, or 180 nm.
  • Re 650 of the optically anisotropic element 60 preferably satisfies the above formula (6d).
  • the front retardation Re 550 of the optically anisotropic element 60 at a wavelength of 550 nm is preferably about twice that of Rt 550 . Therefore, Re 550 preferably satisfies the following formula (8d). 1.38 (Ct 550 ) + C 18 ⁇ Re 550 ⁇ 2.70 (Ct 550 ) + C 19 (8d)
  • C 18 is twice the C 8, in particular C 18 is 140nm or more.
  • C 18 may be 155 nm, 175 nm, 185 nm, 215 nm, 225 nm, 235 nm, 245 nm, or 255 nm.
  • C 19 is twice the C 9, in particular C 19 is 400nm or less.
  • C 19 may be 400 nm, 380 nm, 360 nm, 345 nm, 335 nm, 325 nm, 315 nm, 305 nm, or 295 nm.
  • the optical anisotropic element 50 disposed on the viewing side of the liquid crystal cell 20 corresponding to the thickness direction retardations Ct 550 and Ct 650 of the color filter 22 is predetermined.
  • the optical design is performed so as to have the following optical characteristics.
  • the liquid crystal panel 102 of the second embodiment is optically designed so that the optical anisotropic element 60 disposed on the light source side of the liquid crystal cell 20 has predetermined optical characteristics corresponding to Ct 550 and Ct 650. .
  • the liquid crystal panel 101 of the first embodiment is optically isotropic as a polarizer protective film between the viewing-side polarizer 30 and the optically anisotropic element 50 or between the light source-side polarizer 40 and the liquid crystal cell 20.
  • a film may be provided.
  • the liquid crystal panel 102 of the second embodiment is optically isotropic as a polarizer protective film between the viewing side polarizer 30 and the liquid crystal cell 20 or between the light source side polarizer 40 and the optical anisotropic element 60.
  • a film may be provided.
  • An optically isotropic film used as a polarizer protective film refers to a film that does not substantially change its polarization state with respect to light transmitted through both the normal direction and the oblique direction.
  • the optically isotropic film preferably has a front retardation Re of 10 nm or less, and preferably has a thickness direction retardation Rt of 20 nm or less.
  • the front retardation of the optical isotropic film is more preferably 5 nm or less.
  • the thickness direction retardation of the optical isotropic film is more preferably 10 nm or less, and further preferably 5 nm or less.
  • the liquid crystal panel can also include optical layers and other members other than those described above.
  • a polarizer protective film is preferably provided on the outer surfaces of the polarizers 30 and 40 (surfaces that do not face the liquid crystal cell 20).
  • the polarizer protective film provided on the outer surface of the polarizer may be optically isotropic or may have optical anisotropy.
  • the polarizer protective film provided on the surface of the viewing side polarizer 30 on the liquid crystal cell 20 side and the light source side polarizer 40 on the liquid crystal cell 20 side is required to be optically isotropic as described above.
  • the liquid crystal panel 101 of the first embodiment preferably does not include an optically anisotropic element other than the optically anisotropic element 50 between the viewing side polarizer and the liquid crystal cell 20, and the light source side polarizer 40 and the liquid crystal It is preferable that no optically anisotropic element is included between the cells 20.
  • the liquid crystal panel 102 of the second embodiment preferably does not include an optically anisotropic element other than the optically anisotropic element 60 between the light source side polarizer and the liquid crystal cell 20. It is preferable that no optically anisotropic element is included between the cells 20.
  • a liquid crystal panel is formed by laminating a liquid crystal cell and each of the above optical members.
  • each member may be stacked separately on the liquid crystal cell, or a member in which several members are stacked in advance may be used.
  • the order of stacking these optical members is not particularly limited.
  • a polarizer and an optically anisotropic element may be laminated to form a laminated polarizing plate in advance, and this laminated polarizing plate may be bonded to a liquid crystal cell via an adhesive (not shown).
  • a polarizer protective film may be provided on the surface of the polarizer. Between the polarizer and the optically anisotropic element, an optical isotropic film may be provided as a polarizer protective film.
  • Adhesives and adhesives are based on acrylic polymers, silicone polymers, polyesters, polyurethanes, polyamides, polyvinyl ethers, vinyl acetate / vinyl chloride copolymers, modified polyolefins, epoxy polymers, fluorine polymers, rubber polymers, etc.
  • a polymer can be appropriately selected and used.
  • a liquid crystal display device By arranging the light source 110 on the second main surface side (polarizer 40 side) of the liquid crystal panel, a liquid crystal display device is formed.
  • a brightness enhancement film (not shown) may be provided between the liquid crystal panel and the light source.
  • the brightness enhancement film may be provided integrally with the light source side polarizer.
  • a film obtained by bonding a brightness enhancement film to the outer surface (surface on the light source side) of the second polarizer via an adhesive layer can be used.
  • the polarizer protective film may be provided between the polarizer and the brightness enhancement film.

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  • General Physics & Mathematics (AREA)
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  • Mathematical Physics (AREA)
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Abstract

La présente invention porte sur un panneau à cristaux liquides (101) qui est pourvu d'une cellule à cristaux liquides (20), d'un premier polariseur (30), d'un second polariseur (40) et d'un élément optiquement anisotrope (50). La cellule à cristaux liquides est pourvue d'une couche de cristaux liquides comprenant des molécules de cristaux liquides dans un alignement homogène en l'absence d'un champ électrique, et d'un filtre coloré (22) disposé sur une première surface principale de la couche de cristaux liquides. La direction d'axe lent (53) de l'élément optiquement anisotrope (50) et la direction d'axe d'absorption (45) du second polariseur sont parallèles. Le retard dans le sens de l'épaisseur de l'élément optiquement anisotrope et le retard dans le sens de l'épaisseur du filtre coloré de la cellule à cristaux liquides satisfont à une relation prédéfinie concernant une longueur d'onde de 550 nm et une longueur d'onde de 650 nm.
PCT/JP2019/019813 2018-06-13 2019-05-17 Panneau à cristaux liquides et dispositif d'affichage à cristaux liquides Ceased WO2019239794A1 (fr)

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CN202310842279.7A CN116819830B (zh) 2018-06-13 2019-05-17 液晶面板及液晶显示设备
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