WO2025022978A1 - 視野角制御システム、画像表示装置 - Google Patents

視野角制御システム、画像表示装置 Download PDF

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Publication number
WO2025022978A1
WO2025022978A1 PCT/JP2024/024390 JP2024024390W WO2025022978A1 WO 2025022978 A1 WO2025022978 A1 WO 2025022978A1 JP 2024024390 W JP2024024390 W JP 2024024390W WO 2025022978 A1 WO2025022978 A1 WO 2025022978A1
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Prior art keywords
liquid crystal
crystal cell
optical compensation
layer
film
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English (en)
French (fr)
Japanese (ja)
Inventor
史岳 三戸部
直希 小糸
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Fujifilm Corp
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Fujifilm Corp
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Priority to CN202480048965.XA priority Critical patent/CN121569235A/zh
Priority to JP2025535685A priority patent/JPWO2025022978A1/ja
Publication of WO2025022978A1 publication Critical patent/WO2025022978A1/ja
Anticipated expiration legal-status Critical
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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
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/13363—Birefringent elements, e.g. for optical compensation
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1347—Arrangement of liquid crystal layers or cells in which the final condition of one light beam is achieved by the addition of the effects of two or more layers or cells
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F9/00—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements

Definitions

  • the present invention relates to a viewing angle control system.
  • the present invention also relates to an image display device including the above viewing angle control system.
  • display devices such as liquid crystal display devices have come to be widely used as displays for personal computers, smartphones, and the like. Displays are also often used in mobile devices. Devices with such displays are often used in public places, and there is a demand for technology to prevent others from peeking at them.
  • LCD devices have also come to be used as in-vehicle displays inside automobiles.
  • images shown on the display can be reflected on the windshield, interfering with the driver's field of vision, and there is a demand for technology to prevent such reflections.
  • Patent Document 1 discloses a viewing angle control system that includes a substrate in which dyes are vertically aligned and a switching cell, and that is capable of switching the width of the viewing angle.
  • the viewing angle control system is required to be applied to an image display device and to be able to switch between a transmission mode in which an image can be viewed and a light-shielding mode in which the image is difficult to view when observed from an oblique direction at a specific azimuth angle.
  • a transmission mode in which an image can be viewed and a light-shielding mode in which the image is difficult to view when observed from an oblique direction at a specific azimuth angle.
  • the present inventors have studied the above-mentioned transmission mode and light blocking mode and have found that the technology described in Patent Document 1 does not meet the standards currently required, and further improvement is necessary.
  • an objective of the present invention is to provide a viewing angle control system that can be applied to an image display device and that can switch between a shading mode and a transmission mode when viewed from an oblique direction at a specified azimuth angle, making the image less visible in the shading mode and more visible in the transmission mode.
  • Another object of the present invention is to provide an image display device using the above viewing angle control system.
  • a light absorbing anisotropic layer A liquid crystal cell; a polarizer, an angle between a central axis of transmittance of the optically absorptive anisotropic layer and a normal line to the optically absorptive anisotropic layer is 0 to 45°; an optical compensation layer is provided between the light absorption anisotropic layer and the liquid crystal cell and/or between the liquid crystal cell and the polarizer; A viewing angle control system that does not include another light absorbing anisotropic layer and another polarizer between the light absorbing anisotropic layer and the polarizer.
  • the liquid crystal cell is an in-plane switching type liquid crystal cell.
  • the present invention when applied to an image display device, it is possible to provide a viewing angle control system that can switch between a shading mode and a transmissive mode when viewed from an oblique direction at a predetermined azimuth angle, making it harder to view an image in the shading mode and easier to view an image in the transmissive mode. Moreover, according to the present invention, it is possible to provide an image display device using the above viewing angle control system.
  • FIG. 1 is a schematic cross-sectional view showing one embodiment of an image display device of the present invention.
  • FIG. 1 is a schematic cross-sectional view for explaining the principle of one embodiment of an image display device of the present invention.
  • 1 is a schematic cross-sectional view showing one embodiment of an image display device of the present invention.
  • parallel and perpendicular do not mean parallel and perpendicular in the strict sense, but mean a range of ⁇ 5° from parallel or perpendicular.
  • polar angle means the angle with the normal direction of the film.
  • liquid crystal composition and liquid crystalline compound conceptually include those that no longer exhibit liquid crystallinity due to curing or the like.
  • each component may be used alone or in combination of two or more substances corresponding to each component.
  • the content of the component refers to the total content of the substances used in combination, unless otherwise specified.
  • “(meth)acrylate” is a notation representing "acrylate” or “methacrylate”
  • “(meth)acrylic” is a notation representing "acrylic” or “methacrylic”
  • “(meth)acryloyl” is a notation representing "acryloyl” or "methacryloyl”.
  • NAR-4T Abbe refractometer
  • measurements can be made using a multi-wavelength Abbe refractometer DR-M2 (manufactured by Atago Co., Ltd.) in combination with an interference filter. Values in the Polymer Handbook (John Wiley & Sons, Inc.) and catalogs of various optical films can also be used.
  • DR-M2 manufactured by Atago Co., Ltd.
  • Re( ⁇ ) and Rth( ⁇ ) respectively represent an in-plane retardation and a retardation in the thickness direction at a wavelength ⁇ , and are expressed by the following formulas (1) and (2) using refractive indices nx, ny, and nz and a film thickness d ( ⁇ m).
  • Formula (1): Re( ⁇ ) (nx-ny) ⁇ d ⁇ 1000(nm)
  • Formula (2): Rth ( ⁇ ) ((nx+ny)/2-nz) x d x 1000 (nm)
  • the wavelength ⁇ is 550 nm.
  • ⁇ nd is a phase difference caused by a layer in which a rod-shaped or discotic liquid crystal compound is twisted and aligned around the thickness direction, and is represented by the product of the thickness d of the liquid crystal layer and the birefringence ⁇ n of the liquid crystal.
  • the twist angle of the liquid crystal compound from one surface to the other surface of the layer in which the liquid crystal compound is twisted and aligned is also called the twist angle of the liquid crystal compound.
  • ⁇ n is the value at a wavelength of 550 nm.
  • the viewing angle control system of the present invention includes an optically absorptive anisotropic layer, a liquid crystal cell, and a polarizer in this order, where the angle between the transmittance central axis of the optically absorptive anisotropic layer and a normal to the optically absorptive anisotropic layer is 0 to 45°.
  • an optical compensation layer is provided between the optically absorptive anisotropic layer and the liquid crystal cell and/or between the liquid crystal cell and the polarizer, and no other optically absorptive anisotropic layer or other polarizer is provided between the optically absorptive anisotropic layer and the polarizer.
  • FIG. 1 is a schematic cross-sectional view showing one embodiment of an image display device using the viewing angle control system of the present invention.
  • 1 includes a viewing angle control system 10a and a display panel 20.
  • the image display device 100a has a viewing side opposite to the display panel 20 side of the viewing angle control system 10a.
  • the viewing angle control system 10a includes, in this order from the side opposite to the display panel 20 side (the viewing side), an optically absorptive anisotropic layer 12, a liquid crystal cell 14, an optical compensation layer 18, and a polarizer 16.
  • the angle between the transmittance central axis of the optically absorptive anisotropic layer 12 and the normal to the optically absorptive anisotropic layer 12 is 0 to 45°.
  • the liquid crystal cell 14 shown in Fig. 1 is an in-plane switching (IPS) liquid crystal cell capable of controlling the alignment direction of a liquid crystal compound in an in-plane direction.
  • IPS in-plane switching
  • FIG. 2 is a schematic cross-sectional view of the image display device 100a for illustrating that the image display device 100a can be switched between a light blocking mode and a transmissive mode.
  • the white arrows in Fig. 2 indicate panel light emitted from the display panel 20 in an oblique direction at a predetermined azimuth angle.
  • the configuration of the image display device 100a is the same as that shown in Fig. 1. However, in Fig. 2, the transmission axis direction A16 of the polarizer 16 is the back-to-front direction on the paper.
  • the angle between the central axis of transmittance of the optically absorptive anisotropic layer 12 and the normal to the optically absorptive anisotropic layer 12 is 0°.
  • the orientation direction (direction of the in-plane slow axis) of the liquid crystal compound is controlled to form a predetermined angle (for example, 45°) with the polarization direction of the panel light that has entered the liquid crystal cell 14, and the liquid crystal compound contained in the liquid crystal cell 14 converts the light into light polarized in the left-to-right direction of the paper and exits the liquid crystal cell 14.
  • a predetermined angle for example, 45°
  • the angle that the central axis of transmittance of the optically absorptive anisotropic layer 12 makes with the normal to the optically absorptive anisotropic layer 12 is 0°.
  • the optically absorptive anisotropic layer 12 does not easily absorb light polarized in the depth direction of the page, but easily absorbs light polarized in the left-right direction of the page.
  • panel light polarized in the left-right direction on the paper and incident on the light absorptive anisotropic layer 12 is absorbed by the light absorptive anisotropic layer 12 and is unlikely to exit to the viewing side. That is, the above mode is the light blocking mode.
  • the polarization direction of the panel light is maintained in the back-to-front direction of the page by controlling the orientation direction of the liquid crystal compound contained in the liquid crystal cell 14 so as not to change the polarization direction of the panel light incident on the liquid crystal cell 14.
  • the orientation direction of the liquid crystal compound (direction of the in-plane slow axis) is controlled to form a predetermined angle (e.g., 0°) with the polarization direction of the panel light incident on the liquid crystal cell 14.
  • a predetermined angle e.g., 0°
  • the above mode is a viewing mode. Therefore, as described above, by controlling the alignment direction of the liquid crystal compound contained in the liquid crystal cell 14, it is possible to switch between the light blocking mode and the light transmitting mode.
  • the light-shielding mode and the transmission mode can be switched by controlling the orientation direction of the liquid crystal compound contained in the liquid crystal cell 14 according to the above-mentioned principle.
  • the direction in which the central axis of transmittance of the optically absorptive anisotropic layer 12 is projected from the normal direction of the optically absorptive anisotropic layer 12 onto the surface of the optically absorptive anisotropic layer 12 is the left-right direction of the paper.
  • the angle between the central axis of transmittance of the optically absorptive anisotropic layer 12 and the normal to the optically absorptive anisotropic layer 12 is not 0°
  • the direction in which the central axis of transmittance of the optically absorptive anisotropic layer 12 is projected from the normal direction of the optically absorptive anisotropic layer 12 onto the surface of the optically absorptive anisotropic layer 12 is perpendicular to the transmission axis direction A16 of the polarizer 16.
  • the direction of the central axis of transmittance of the light absorptive anisotropic layer 12 is a predetermined angle other than 0°.
  • panel light emitted from the display panel 20 is easily transmitted, and images displayed on the display panel 20 are easily visible.
  • the viewing angle control system 10a has, in this order from the side opposite to the display panel 20 (the viewing side), the optically absorptive anisotropic layer 12, the liquid crystal cell 14, the optical compensation layer 18, and the polarizer 16.
  • the viewing angle control system of the present invention is not limited to the above embodiment, and the optically anisotropic layer 18 may be disposed between the optically absorptive anisotropic layer 12 and the liquid crystal cell 14.
  • the image display device of the above embodiment will be described with reference to FIG. Fig. 3 is a schematic cross-sectional view showing one embodiment of an image display device using the viewing angle control system of the present invention.
  • the image display device 100b shown in Fig. 3 has a viewing angle control system 10b and a display panel 20.
  • the image display device 100b has a viewing side opposite to the display panel 20 side of the viewing angle control system 10b.
  • the viewing angle control system 10b has, in this order from the side opposite to the display panel 20 side (the viewing side), an optically absorptive anisotropic layer 12, an optical compensation layer 18, a liquid crystal cell 14, and a polarizer 16.
  • the optically absorptive anisotropic layer 12 forms an angle of 0 to 45° with respect to the normal to the optically absorptive anisotropic layer 12.
  • the light-shielding mode and the light-transmitting mode can be switched by controlling the orientation direction of the liquid crystal compound contained in the liquid crystal cell 14 using the same principle as that described in Figures 1 and 2.
  • the light-shielding mode and the transmission mode can be switched by controlling the alignment direction of the liquid crystal compound contained in the liquid crystal cell 14. That is, when viewed from an oblique direction at a predetermined azimuth angle, the light-shielding mode and the transmission mode can be switched.
  • an image is less visible in the light blocking mode, and more visible in the transmission mode.
  • optical members such as liquid crystal cells have a finite thickness
  • they may have a phase difference not only in the in-plane direction but also in the thickness direction.
  • the light senses not only the phase difference in the in-plane direction but also, for example, the phase difference in the thickness direction, and undergoes a polarization conversion different from that when the light is incident from the front direction.
  • an optical compensation layer is provided between the light absorption anisotropic layer and the liquid crystal cell, and at least one between the liquid crystal cell and the polarizer, it is possible to compensate for the above phase difference, for example, and to bring the light closer to a polarization state that is easily absorbed by the light absorption anisotropic layer or is not easily absorbed by the light absorption anisotropic layer. It is considered that, then, the image is more difficult to view in the light blocking mode, and the image is more easily viewable in the transmission mode.
  • the method of switching the alignment direction of the liquid crystal compound is not limited to the above embodiment, and any known method can be used.
  • the liquid crystal cell 14 is an IPS type liquid crystal cell, but the liquid crystal cell may be of the type described below.
  • the optical compensation layer is disposed either between the light absorption anisotropic layer and the liquid crystal cell or between the liquid crystal cell and the polarizer, but the optical compensation layer may be disposed between both of the above.
  • the viewing angle control system of the present invention does not include another optically absorptive anisotropic layer and another polarizer between the optically absorptive anisotropic layer and the polarizer.
  • the viewing angle control system 10a means that the liquid crystal cell 14 does not include another polarizer, and that no other polarizer is included between the polarizer 16 and the liquid crystal cell 14, and between the optically absorptive anisotropic layer 12 and the liquid crystal cell 14. It also means that no other optically absorptive anisotropic layer is included between the liquid crystal cell 14 and the polarizer 16. At least one of another polarizer and another light absorptive anisotropic layer may be disposed between the polarizer 16 and the display panel 20 .
  • each configuration included in the viewing angle control system can be modified as in the example configurations shown below, and the modified configurations can also be combined.
  • excellent light-blocking properties the fact that an image is less visible in the light-blocking mode is also referred to as "excellent light-blocking properties”
  • excellent transmission properties the fact that an image is more visible in the transmission mode
  • the angle between the transmittance central axis of the optically absorptive anisotropic layer and the normal to the optically absorptive anisotropic layer is 0 to 45°.
  • the optically absorptive anisotropic layer preferably contains a dichroic material.
  • the transmittance central axis usually coincides with the alignment direction of the dichroic material. The angle can be adjusted according to the direction in which the image is to be viewed.
  • the angle is preferably 0 to 10°.
  • the central axis of transmittance of the optically absorptive anisotropic layer may be oriented in a different direction depending on the location in the plane of the optically absorptive anisotropic layer.
  • an in-vehicle display having a curved display surface in order to prevent light emitted from any position from being reflected on the windshield or the like and to enable the driver to properly view the displayed image, it is preferable to adjust the direction of the central axis of transmittance of the optically absorptive anisotropic layer in accordance with the curved surface.
  • the above-mentioned transmittance central axis means the direction in which the transmittance is highest when the transmittance is measured by changing the tilt angle (polar angle) and tilt direction (azimuth angle) relative to the normal direction of the optically absorptive anisotropic layer surface.
  • AxoScan OPMF-2 manufactured by Axometrics
  • AxoScan OPMF-2 manufactured by Axometrics
  • the Mueller matrix is measured while changing the polar angle in various ways to derive the transmittance, and the direction (polar angle) in which the transmittance is highest is taken as the direction of the transmittance central axis of the optically absorptive anisotropic layer.
  • the direction of this polar angle is the angle formed by the transmittance central axis in the optically absorptive anisotropic layer and the normal direction of the optically absorptive anisotropic layer.
  • the transmittance central axis (polar angle) of the optically absorptive anisotropic layer is measured at 15 arbitrarily selected points in the optically absorptive anisotropic layer, and the average of the polar angles is regarded as the transmittance central axis of the optically absorptive anisotropic layer.
  • these optical measurements are carried out using light with a wavelength of 550 nm, unless otherwise specified.
  • the light transmittance of the light absorbing anisotropic layer in a direction parallel to the central axis of the transmittance is preferably 50% or more, more preferably 70% or more.
  • the upper limit of the transmittance is not particularly limited, but may be, for example, 95% or less, and is often 90% or less.
  • the transmittance in a direction inclined by 30° from the central axis of the transmittance of the light absorbing anisotropic layer is preferably 30% or less, more preferably 15% or less.
  • the lower limit of the transmittance is not particularly limited, but may be, for example, 0.5% or more, and is often 5% or more.
  • the light absorptive anisotropic layer in the present invention is preferably a layer containing at least one kind of dichroic substance (for example, a dichroic dye).
  • the dichroic substance is not particularly limited as long as it is a substance that exhibits dichroism, and examples of the dichroic substance include dichroic dyes, dichroic azo dye compounds, ultraviolet absorbing substances, infrared absorbing substances, nonlinear optical substances, carbon nanotubes, anisotropic metal nanoparticles, and inorganic substances.
  • the light absorption anisotropic layer may contain two or more dichroic substances.
  • a cyan dye exhibiting dichroism in the red wavelength region a magenta dye exhibiting dichroism in the green wavelength region, and a yellow dye exhibiting dichroism in the blue wavelength region.
  • the light absorption anisotropic layer contains a plurality of dichroic substances, the color can be made neutral and the viewing angle control effect can be exerted over the entire wavelength region of visible light.
  • a dichroic substance is a substance that exhibits dichroism, and dichroism refers to a property in which the absorbance differs depending on the direction of polarization.
  • the degree of orientation of the dichroic material at a wavelength of 550 nm is preferably 0.95 or more.
  • the degree of orientation of the dichroic material When the degree of orientation of the dichroic material is 0.95 or more, the transmittance in the direction of the absorption axis (i.e., the direction in which light is to be transmitted) can be increased.
  • the degree of orientation of the dichroic material at a wavelength of 420 nm is preferably 0.93 or more.
  • the thickness of the optically absorptive anisotropic layer is not particularly limited, but from the viewpoint of flexibility, it is preferably from 100 to 8,000 nm, and more preferably from 300 to 5,000 nm.
  • a dichroic dye will be described below.
  • the dichroic azo dye compound means an azo dye compound whose absorbance varies depending on the direction.
  • the dichroic azo dye compound may or may not exhibit liquid crystallinity.
  • the dichroic azo dye compound exhibits liquid crystallinity, it may exhibit either a nematic liquid crystal phase or a smectic liquid crystal phase.
  • the temperature range in which the liquid crystal phase is exhibited is preferably from room temperature (about 20 to 28° C.) to 300° C., and more preferably from 50 to 200° C. from the viewpoints of handling and manufacturing suitability.
  • the dichroic azo dye compound in the composition for forming the optically absorptive anisotropic layer used in forming the optically absorptive anisotropic layer described later has a crosslinkable group.
  • the crosslinkable group include a (meth)acryloyl group, an epoxy group, an oxetanyl group, and a styryl group, and among these, a (meth)acryloyl group is preferable.
  • the dichroic azo dye compound used in the present invention include a first dichroic azo dye compound, a second dichroic azo dye compound, and a third dichroic azo dye compound.
  • the first dichroic azo dye compound is a dichroic azo dye compound having a maximum absorption wavelength in the wavelength range of 560 nm to 700 nm
  • the second dichroic azo dye compound is a dichroic azo dye compound having a maximum absorption wavelength in the wavelength range of 455 nm to less than 560 nm
  • the third dichroic azo dye compound is a dichroic azo dye compound having a maximum absorption wavelength in the wavelength range of 380 nm to 455 nm.
  • first dichroic azo dye compound examples include, for example, the compounds described in paragraphs [0161] to [0171] of WO 2022/138548, the compounds described in paragraphs [0172] to [0180] of WO 2022/138548, and the compounds described in paragraphs [0183] to [0206] of WO 2022/138548.
  • the content of the dichroic material is preferably 1 to 30% by mass, more preferably 5 to 25% by mass, and even more preferably 10 to 20% by mass, based on the total solid mass of the light absorbing anisotropic layer.
  • the optically absorptive anisotropic layer is preferably formed using a liquid crystal composition containing a dichroic material and a liquid crystal compound, and therefore preferably contains a component derived from the liquid crystal compound.
  • a liquid crystal composition containing a dichroic material and a liquid crystal compound, and therefore preferably contains a component derived from the liquid crystal compound.
  • the liquid crystal compound either a low molecular weight liquid crystal compound or a polymeric liquid crystal compound can be used, and it is also preferable to use both in combination.
  • the term “low molecular weight liquid crystal compound” refers to a liquid crystal compound that does not have a repeating unit in its chemical structure.
  • polymeric liquid crystal compound refers to a liquid crystal compound that has a repeating unit in its chemical structure.
  • the low molecular weight liquid crystal compound may be either a compound exhibiting a nematic liquid crystal phase or a compound exhibiting a smectic liquid crystal phase, but from the viewpoint of increasing the degree of orientation, a compound exhibiting a smectic liquid crystal phase is preferred.
  • a compound exhibiting a smectic liquid crystal phase is preferred.
  • the liquid crystal compounds described in JP 2013-228706 A can be mentioned.
  • the polymer liquid crystal compound examples include the thermotropic liquid crystal polymers described in JP 2011-237513 A. From the viewpoint of excellent strength (particularly the bending resistance of the film), the polymer liquid crystal compound preferably has a repeating unit having a crosslinkable group at the end.
  • the crosslinkable group examples include the polymerizable groups described in paragraphs [0040] to [0050] of JP 2010-244038 A. Among these, from the viewpoint of improving reactivity and suitability for synthesis, acryloyl groups, methacryloyl groups, epoxy groups, oxetanyl groups, and styryl groups are preferred, and acryloyl groups and methacryloyl groups are more preferred.
  • the polymer liquid crystal compound When the light absorption anisotropic layer contains a polymer liquid crystal compound, the polymer liquid crystal compound preferably forms a nematic liquid crystal phase.
  • the temperature range in which the nematic liquid crystal phase is exhibited is preferably room temperature (23°C) to 450°C, and from the viewpoint of handling and manufacturing suitability, 50 to 400°C is preferable.
  • the content of the component derived from the liquid crystal compound in the light absorption anisotropic layer is preferably 25 to 2000 parts by mass, more preferably 100 to 1300 parts by mass, and even more preferably 200 to 900 parts by mass, relative to 100 parts by mass of the dichroic substance.
  • the liquid crystal compound may be contained alone or in combination with two or more kinds.
  • the content of the components derived from the liquid crystal compounds means the total content of the liquid crystal compounds.
  • the liquid crystal composition used for forming the light absorption anisotropic layer may further contain additives such as a solvent, a vertical alignment agent, an interface improver, a leveling agent, a polymerizable component, a polymerization initiator (e.g., a radical polymerization initiator), a durability improver, etc.
  • additives such as a solvent, a vertical alignment agent, an interface improver, a leveling agent, a polymerizable component, a polymerization initiator (e.g., a radical polymerization initiator), a durability improver, etc.
  • known additives can be appropriately used.
  • the viewing angle control system of the present invention may include other layers different from the optically absorbing anisotropic layer and the layers described below.
  • the other layers are layers that are in direct contact with the optically absorbing anisotropic layer, or indirectly in contact with the optically absorbing anisotropic layer via a layer different from the optically absorbing anisotropic layer and the layers described below.
  • the other layers that are in direct or indirect contact with the optically absorbing anisotropic layer are described below.
  • the viewing angle control system of the present invention may include a substrate layer as another layer.
  • the substrate layer is not particularly limited, but a transparent film or sheet is preferable, and a known transparent resin film, transparent resin plate, transparent resin sheet, glass, etc. can be used.
  • a cellulose acylate film e.g., a cellulose triacetate film, a cellulose diacetate film, a cellulose acetate butyrate film, a cellulose acetate propionate film
  • a polyethylene terephthalate film e.g., a polyethersulfone film
  • a polyacrylic resin film e.g., a polyurethane resin film
  • a polyester film a polycarbonate film
  • a polysulfone film a polyether film, a polymethylpentene film, a polyether ketone film, a (meth)acrylonitrile film, etc.
  • a cellulose acylate film e.g., a cellulose triacetate film, a cellulose diacetate film, a cellulose acetate butyrate film, a cellulose acetate propionate film
  • a polyethylene terephthalate film e.g., a polyethersulfone film, a polyacryl
  • a cellulose acylate film is preferred, and a cellulose triacetate film is particularly preferred, because it has high transparency, has little optical birefringence, is easy to produce, and is generally used as a protective film for a polarizer.
  • the thickness of the transparent resin film is preferably 20 ⁇ m to 100 ⁇ m.
  • the viewing angle control system of the present invention may have an alignment film between the substrate layer and the light absorptive anisotropic layer as another layer.
  • the alignment film may be any layer as long as it can cause the dichroic material (liquid crystal compound) on the alignment film to be aligned in a desired state.
  • a film formed from a polyfunctional acrylate compound and polyvinyl alcohol may be used, with polyvinyl alcohol being particularly preferred.
  • the alignment film may be a photo-alignment film.
  • the dichroic material By irradiating a photo-alignment film containing an azo compound or a cinnamoyl compound with UV light from an oblique direction, the dichroic material can be aligned at an angle with respect to the normal direction of the film.
  • the viewing angle control system of the present invention may include a barrier layer as another layer.
  • the barrier layer is also called a gas barrier layer (oxygen barrier layer), and has the function of protecting the light absorption anisotropic layer from gases such as oxygen in the atmosphere, moisture, or compounds contained in adjacent layers.
  • the optically absorptive anisotropic layer may have a problem of internal reflection due to the high refractive index of the optically absorptive anisotropic layer.
  • a refractive index adjustment layer may be used.
  • the refractive index adjustment layer is preferably disposed in contact with the optically absorptive anisotropic layer and is a layer for performing so-called index matching.
  • the in-plane average refractive index of the refractive index adjustment layer at a wavelength of 550 nm is preferably 1.55 or more and 1.70 or less.
  • the method for forming the optically absorptive anisotropic layer is not particularly limited, and examples thereof include a method including, in this order, a step of applying a composition for forming an optically absorptive anisotropic layer to form a coating film (hereinafter also referred to as a "coating film forming step") and a step of orienting a liquid crystalline component or a dichroic material contained in the coating film (hereinafter also referred to as an "orientation step").
  • the liquid crystal component is a component including not only the above-mentioned liquid crystal compound but also a dichroic substance having liquid crystallinity when the above-mentioned dichroic substance has liquid crystallinity.
  • the coating film forming step is a step of forming a coating film by applying a composition for forming an optically absorptive anisotropic layer.
  • a composition for forming an optically absorptive anisotropic layer that contains a solvent or by using a composition for forming an optically absorptive anisotropic layer that has been made into a liquid such as a molten liquid by heating or the like, it becomes easy to apply the composition for forming an optically absorptive anisotropic layer.
  • Specific examples of the method for applying the composition for forming the optically absorptive anisotropic layer include known methods such as roll coating, gravure printing, spin coating, wire bar coating, extrusion coating, direct gravure coating, reverse gravure coating, die coating, spraying, and inkjet methods.
  • the alignment step is a step for aligning the liquid crystal component contained in the coating film, thereby obtaining a light absorptive anisotropic layer.
  • the orientation step may include a drying treatment. By the drying treatment, components such as a solvent can be removed from the coating film. The drying treatment may be performed by leaving the coating film at room temperature for a predetermined time (for example, natural drying), or may be performed by heating and/or blowing air.
  • the liquid crystal component contained in the composition for forming an optically absorptive anisotropic layer may be aligned by the above-mentioned coating film forming step or drying treatment.
  • the coating film is dried to remove the solvent from the coating film, thereby obtaining a coating film having optical absorption anisotropy (i.e., an optically absorptive anisotropic layer).
  • the drying treatment is carried out at a temperature equal to or higher than the temperature at which the liquid crystal component contained in the coating film transitions from the liquid crystal phase to the isotropic phase, the heating treatment described below does not need to be carried out.
  • the transition temperature from the liquid crystal phase to the isotropic phase of the liquid crystal component contained in the coating film is preferably 10 to 250°C, more preferably 25 to 190°C, from the standpoint of manufacturability, etc.
  • a transition temperature of 10°C or higher is preferable because no cooling process or the like is required to lower the temperature to the temperature range in which the liquid crystal phase is exhibited.
  • a transition temperature of 250°C or lower is preferable because high temperatures are not required even when heating until the isotropic phase is achieved in order to suppress alignment defects, and this reduces waste of thermal energy as well as deformation and deterioration of the substrate.
  • the alignment step preferably includes a heat treatment, which allows the liquid crystal component contained in the coating film to be aligned, so that the coating film after the heat treatment can be suitably used as a light absorption anisotropic layer.
  • the heat treatment is preferably performed at 10 to 250° C., more preferably 25 to 190° C.
  • the heating time is preferably 1 to 300 seconds, more preferably 1 to 60 seconds.
  • the orientation process may include a cooling process carried out after the heating process.
  • the cooling process is a process in which the coated film after heating is cooled to about room temperature (20 to 25°C). This makes it possible to fix the orientation of the liquid crystal component contained in the coated film.
  • the method for forming the optically absorptive anisotropic layer may include a step of curing the optically absorptive anisotropic layer (hereinafter also referred to as a "curing step") after the above-mentioned alignment step.
  • the curing step is carried out by heating and/or light irradiation (exposure) when the compound contained in the light absorption anisotropic layer has a crosslinkable group (polymerizable group), for example.
  • the curing step is preferably carried out by light irradiation from the viewpoint of productivity.
  • the light source used for curing may be various light sources such as infrared light, visible light, or ultraviolet light, but ultraviolet light is preferred.
  • ultraviolet light may be irradiated while heating during curing, or ultraviolet light may be irradiated through a filter that transmits only specific wavelengths.
  • the heating temperature during exposure is preferably 25 to 140° C., although it depends on the transition temperature of the liquid crystal component contained in the liquid crystal film.
  • the exposure may be carried out under a nitrogen atmosphere.
  • the curing of the liquid crystal film proceeds by radical polymerization, it is preferable to carry out the exposure under a nitrogen atmosphere, since this reduces the inhibition of polymerization caused by oxygen.
  • the light absorbing anisotropic layer may contain a dichroic dye and a guest-host liquid crystal material, as described in JP-A-2013-541727, for example, and may be capable of electrically driving the orientation direction of the dichroic dye. In this case, it becomes possible to electrically switch the orientation direction of the dichroic dye.
  • the liquid crystal cell included in the viewing angle control system of the present invention is disposed between the light absorbing anisotropic layer and the polarizer, and switches between a light blocking mode and a transmission mode by controlling the orientation direction of the liquid crystal compound included in the liquid crystal cell.
  • the liquid crystal cell is not particularly limited as long as it can be switched between a light-shielding mode and a transmission mode, and a known liquid crystal cell can be used.
  • the liquid crystal cell may have a plurality of regions in which the alignment direction of the liquid crystal compound can be controlled.
  • the liquid crystal cell has a plurality of regions in which the alignment direction of the liquid crystal compound can be controlled, it is also possible to control the alignment direction of the liquid crystal compound in each region independently, and to switch between a light-shielding mode and a transmission mode for the regions of the display panel corresponding to each region.
  • the type of the liquid crystal cell is not particularly limited, and any known type can be used.
  • examples of the type of the first liquid crystal cell include a twisted nematic (TN) type, a vertical alignment (VA) type, an electrically controlled birefringence (ECB) type, and an optically compensated bend (OCB) type.
  • the type of the liquid crystal cell may be a STN (Super Twisted Nematic) type having a twist angle of 180° or more, or a VATN (Vertically Aligned Twisted Nematic) type disclosed in Japanese Patent Laid-Open No.
  • the type of the liquid crystal cell is preferably selected from the group consisting of the TN type, the IPS type, the ECB type, and the VA type, and the IPS type is preferable.
  • TN type liquid crystal cells when no voltage is applied, the rod-shaped liquid crystal molecules are essentially aligned horizontally, and are further twisted at an angle of 60 to 120 degrees along the thickness direction.
  • TN type liquid crystal cells are most commonly used as color TFT (Thin Film Transistor) liquid crystal display devices, and are described in numerous publications.
  • VA mode liquid crystal cells rod-shaped liquid crystal molecules are aligned substantially vertically when no voltage is applied.
  • VA mode liquid crystal cells include (1) narrowly defined VA mode liquid crystal cells (described in JP-A-2-176625) in which rod-shaped liquid crystal molecules are aligned substantially vertically when no voltage is applied and substantially horizontally when voltage is applied, (2) multi-domain (MVA mode) liquid crystal cells (described in SID97, Digest of tech.
  • the method may be any of the PVA (Patterned Vertical Alignment) method, the optical alignment method, and the PSA (Polymer-Sustained Alignment) method. Details of these methods are described in detail in JP 2006-215326 A and JP 2008-538819 A.
  • the rod-shaped liquid crystal molecules are aligned essentially parallel to the substrate, and when a voltage is applied between the electrodes to generate an electric field parallel to the substrate surface, the liquid crystal molecules respond in a planar manner.
  • ECB type liquid crystal cells generate an electric field perpendicular to the substrate surface, which changes the alignment direction of the liquid crystal molecules.
  • ECB type liquid crystal cells are generally a type in which, when an electric field is generated, the liquid crystal molecules align along the thickness direction of the cell.
  • the in-plane retardation (Re(550)) of the liquid crystal cell is preferably from 100 to 500 nm, more preferably from 120 to 450 nm.
  • the alignment direction of the liquid crystal compound can be controlled in the in-plane direction, and it is preferable that the angle between the absorption axis of the polarizer described below and the in-plane slow axis of the liquid crystal cell can be controlled to at least 0 to 5° or 85 to 95°.
  • the angle between the absorption axis of the polarizer and the in-plane slow axis of the liquid crystal cell can be appropriately adjusted according to the in-plane retardation value of the liquid crystal cell.
  • the angle between the absorption axis of the polarizer and the in-plane slow axis of the liquid crystal cell is preferably controllable to 15 to 75°, and more preferably controllable to 20 to 70°.
  • the angle is more preferably 20 to 40° or 50 to 70°, and particularly preferably 20 to 30° or 60 to 70°, in terms of being superior in at least one of light blocking property and transmittance.
  • Requirement 1 The in-plane retardation (Re(550)) of an IPS liquid crystal cell at a wavelength of 550 nm is 300 to 450 nm.
  • Requirement 2 An IPS-type liquid crystal cell can be switched between two states, and in one of the two states, the angle between the in-plane slow axis of the liquid crystal cell and the absorption axis of the polarizer is 0 to 5° or 85 to 95°, and in the other of the two states, the angle between the in-plane slow axis of the liquid crystal cell and the absorption axis of the polarizer is 20 to 35°.
  • Requirement 3 The ⁇ nd of a VA or ECB liquid crystal cell at a wavelength of 550 nm is 500 to 900 nm.
  • Requirement 4 A VA-mode or ECB-mode liquid crystal cell can be switched between two states, and in one of the two states, the angle between the in-plane slow axis of the liquid crystal cell and the absorption axis of the polarizer is 0 to 10°.
  • Requirement 5 In one of the two states in Requirement 4 above, the voltage of the liquid crystal cell is 1.5 to 3.5 V, and in the other of the two states, the voltage is OFF.
  • the liquid crystal cell may be capable of being controlled (halftone display) between the light-shielding mode and the transmission mode, that is, the alignment direction of the liquid crystal compound may be controlled to be intermediate between the alignment direction of the liquid crystal compound in the light-shielding mode and the alignment direction of the liquid crystal compound in the transmission mode.
  • the liquid crystal compound is aligned in a specific direction, so that the magnitude of birefringence caused by the liquid crystal compound when observed obliquely differs between the alignment direction and the direction perpendicular to the alignment direction, which may result in differences in brightness and color tone.
  • a region in which the alignment direction of the liquid crystal compound in the liquid crystal cell can be controlled may be further divided into a plurality of regions, which is called a multi-domain structure.
  • the multi-domain structure the viewing angle characteristics of brightness and color tone are averaged, making it easier to reduce differences in brightness and color tone.
  • regions e.g., regions corresponding to a single pixel
  • the same effect can be obtained by forming each of the above-mentioned regions from two or more different regions in which the alignment direction of the liquid crystal compound changes continuously under a voltage application state.
  • the above-mentioned region of the liquid crystal cell may be divided into multiple regions, which is called a multi-domain structure.
  • a multi-domain structure is preferable because it averages out the viewing angle characteristics in the vertical and horizontal directions, etc., and improves the display quality.
  • the viewing angle control system of the present invention has an optical compensation layer at least one between the light absorbing anisotropic layer and the liquid crystal cell and between the liquid crystal cell and the polarizer.
  • the optical compensation layer preferably exhibits a retardation (Rth) in the thickness direction.
  • the absolute value of Rth of the optical compensation layer is preferably 50 nm or more, more preferably 100 nm or more.
  • the absolute value of Rth of the optical compensation layer is preferably 600 nm or less, more preferably 500 nm or less.
  • the in-plane retardation (Re) of the optical compensation layer is preferably 0 nm or more, more preferably 3 nm or more, and is preferably 300 nm or less, more preferably 250 nm or less.
  • the Nz factor of the optical compensation layer is preferably ⁇ 100 to 100, and more preferably ⁇ 75 to 75.
  • an A plate, a B plate or a C plate is preferable, a B plate or a C plate is more preferable, and a B plate is further preferable.
  • a plates There are two types of A plates: positive A plates (positive A plates, +A plates) and negative A plates (negative A plates, -A plates).
  • the refractive index in the slow axis direction in the film plane is nx
  • the refractive index in the direction perpendicular to the slow axis in the plane is ny
  • the refractive index in the thickness direction is nz
  • the positive A plate satisfies the relationship of formula (A1)
  • the negative A plate satisfies the relationship of formula (A2).
  • the positive A plate has a positive Rth value
  • the negative A plate has a negative Rth value.
  • the slow axis direction in the film plane is the direction in which the refractive index in the plane is maximum.
  • Formula (A1) nx>ny ⁇ nz
  • Formula (A2) ny ⁇ nx ⁇ nz
  • ⁇ includes not only the case where the two are completely identical, but also the case where the two are substantially identical.
  • “ny ⁇ nz” includes the case where (ny-nz) ⁇ d is -10 to 10 nm, preferably -5 to 5 nm
  • “nx ⁇ nz” includes the case where (nx-nz) ⁇ d is -10 to 10 nm, preferably -5 to 5 nm.
  • d is the thickness of the film.
  • the B plate has different values of nx, ny, and nz.
  • C plates There are two types of C plates: a positive C plate (positive C plate, +C plate) and a negative C plate (negative C plate, -C plate).
  • a positive C plate satisfies the relationship of formula (C1)
  • a negative C plate satisfies the relationship of formula (C2).
  • a positive C plate has a negative Rth value
  • a negative C plate has a positive Rth value.
  • Formula (C1) nz>nx ⁇ ny
  • Formula (C2) nz ⁇ nx ⁇ ny
  • ⁇ includes not only the case where the two are completely identical, but also the case where the two are substantially identical.
  • nx-nyxd is 0 to 10 nm, preferably 0 to 5 nm, as "nx ⁇ ny.”
  • d is the thickness of the film.
  • the liquid crystal cell is of an IPS system and has an Re of 250 to 300 nm.
  • the angle between the absorption axis of a polarizer described below and the in-plane slow axis of the liquid crystal cell can be controlled to be 85 to 95° or 40 to 50°.
  • the optical compensation layer preferably satisfies the following relationships (1A) and (1B), and more preferably satisfies the following relationships (1C) and (1D).
  • the liquid crystal cell is of an IPS type and has an Re of 250 to 300 nm.
  • the angle between the absorption axis of a polarizer described later and the in-plane slow axis of the liquid crystal cell can be controlled to be 85 to 95° or 40 to 50°.
  • the optical compensation layer preferably satisfies the following relationships (2A) and (2B), and more preferably satisfies the following relationships (2C) and (2D).
  • the liquid crystal cell is of an IPS mode and has an Re of 115 to 165 nm.
  • the angle between the absorption axis of a polarizer described below and the in-plane slow axis of the liquid crystal cell can be controlled to be 85 to 95° or 40 to 50°.
  • the optical compensation layer preferably satisfies the following relationships (3A) and (3B), and more preferably satisfies the following relationships (3C) and (3D). Note that, satisfying the relationship (3B) or (3D) means satisfying either one of the inequalities described in each of the following relationships.
  • the liquid crystal cell is of an IPS system and has an Re of 375 to 425 nm.
  • the angle between the absorption axis of a polarizer described below and the in-plane slow axis of the liquid crystal cell can be controlled to be 85 to 95° or 40 to 50°.
  • the optical compensation layer preferably satisfies the following relationships (4A) and (4B), and more preferably satisfies the following relationships (4C) and (4D). Note that, satisfying the relationship (4B) or (4D) means satisfying either one of the inequalities described in each of the following relationships. (4A) 0nm ⁇ Re ⁇ 125nm (4B) Nz ⁇ -0.3, 1.3 ⁇ Nz (4C) 0nm ⁇ Re ⁇ 100nm (4D) Nz ⁇ -0.5, 1.5 ⁇ Nz
  • the liquid crystal cell is of an IPS mode and has an Re of 250 to 300 nm.
  • the angle between the absorption axis of a polarizer described later and the in-plane slow axis of the liquid crystal cell can be controlled to be in the range of 85 to 95° or in the range of 20 to 35°.
  • the optical compensation layer preferably satisfies the following relationships (5A) and (5B), more preferably satisfies the following relationships (5C) and (5D), and further preferably satisfies the following relationships (5E) and (5F).
  • the liquid crystal cell is of an IPS system and has an Re of 325 to 375 nm.
  • the angle between the absorption axis of a polarizer described later and the in-plane slow axis of the liquid crystal cell can be controlled to 85 to 95° or 20 to 35°.
  • the optical compensation layer preferably satisfies the following relationships (6A) and (6B), more preferably satisfies the following relationships (6C) and (6D), and more preferably satisfies the following relationships (6E) and (6F).
  • the liquid crystal cell is of the VA mode or ECB mode, and the ⁇ nd of the liquid crystal cell is 210 to 300 nm.
  • the angle between the absorption axis of a polarizer described later and the in-plane slow axis of the liquid crystal cell can be controlled to a state of 35 to 55° (horizontal alignment mode), and the alignment direction of the liquid crystal compound in the liquid crystal cell can be controlled to a state parallel to the thickness direction of the liquid crystal cell (vertical alignment mode).
  • the optical compensation layer preferably satisfies the following relationships (7A) and (7B), more preferably satisfies the following relationships (7C) and (7D), and also preferably satisfies the following relationships (7C) and (7E).
  • the liquid crystal cell is of the VA mode or ECB mode, and the ⁇ nd of the liquid crystal cell is 210 to 300 nm.
  • the angle between the absorption axis of a polarizer described later and the in-plane slow axis of the liquid crystal cell can be controlled to a state of 35 to 55° (horizontal alignment mode), and the alignment direction of the liquid crystal compound in the liquid crystal cell can be controlled to a state parallel to the thickness direction of the liquid crystal cell (vertical alignment mode).
  • the optical compensation layer preferably satisfies the following relationships (8A) and (8B), and more preferably satisfies the following relationships (8C) and (8D).
  • the liquid crystal cell is of a VA mode or an ECB mode, and ⁇ nd of the liquid crystal cell is 500 to 900 nm.
  • the angle between the absorption axis of a polarizer described later and the in-plane slow axis of the liquid crystal cell can be controlled to a state of 0 to 10° or 80 to 100° (horizontal alignment mode), and the alignment direction of the liquid crystal compound in the liquid crystal cell can be controlled to a state parallel to the thickness direction of the liquid crystal cell (vertical alignment mode).
  • the optical compensation layer preferably satisfies the following relationships (9A) and (9B), and more preferably satisfies the following relationships (9C) and (9D). It is also preferable to satisfy the following relationships (9C) and (9E).
  • satisfying the relationship (9B) or (9D) means satisfying either one of the inequalities described in the following relationships.
  • the liquid crystal cell multi-domain.
  • the alignment direction of the liquid crystal compound in the liquid crystal cell differs between one domain and the other domain, but the alignment direction of the liquid crystal compound may change continuously between the domains.
  • the optical compensation layer has an in-plane slow axis
  • linear polarizers include polarizers in which a dichroic material is dyed onto polyvinyl alcohol or other polymer resins and then stretched to align them horizontally, and polarizers in which a dichroic material is oriented horizontally by utilizing the orientation properties of liquid crystals.
  • the polarizer may be a reflective polarizer or a laminate of an absorbing polarizer and a reflective polarizer.
  • a reflective polarizer is a polarizer that reflects one polarized light and transmits the other polarized light.
  • a reflective polarizer has a reflection axis and a transmission axis in the plane, but the reflection axis works in the same way as the absorption axis in a normal polarizer (absorbent polarizer) in the sense that it does not transmit polarized light in that direction. Therefore, in this specification, the reflection axis of a reflective polarizer can be interpreted as the absorption axis.
  • the viewing angle control system of the present invention may include layers (other layers) other than those configured as described above.
  • the other layers include a protective film, an adhesive layer, an adhesive layer, a diffusion sheet, a prism sheet, a reflective sheet, etc.
  • known layers can be used as the other layers.
  • the image display device of the present invention includes the viewing angle control system of the present invention.
  • the image display device is not particularly limited, and examples thereof include a liquid crystal display device, an electroluminescence display device, and a plasma display device.
  • the image display device may be used as, for example, a display, a head-up display, a head-mounted display, or the like.
  • the image display device of the present invention may be used in combination with a configuration that is generally used in this field.
  • the image display device of the present invention may be combined with a protective film, a depolarizing film, an optical compensation film, and the like.
  • the image display device of the present invention includes a viewing angle control system and a display panel.
  • the display panel may be a display panel using a liquid crystal display element, an electroluminescence display element, or a plasma display element.
  • a liquid crystal display element When a liquid crystal display element is used as the display element, it may be equipped with a backlight, or may be a transmissive liquid crystal display element without a backlight.
  • the electroluminescent display element include an organic electroluminescent (organic EL) display element, an inorganic electroluminescent (inorganic EL) display element, and a light-emitting diode display element, with the organic EL display element or the light-emitting diode display element being preferred.
  • the image display device of the present invention can be switched between a light-shielding mode and a light-transmitting mode when viewed from an oblique direction at a predetermined azimuth angle. Furthermore, the image display device of the present invention has excellent light-shielding and light-transmitting properties. Due to the above characteristics, the image display device of the present invention can be used as an image display device capable of changing visibility from an oblique direction at a predetermined azimuth angle.
  • the image display device of the present invention when the image display device of the present invention is applied to an in-vehicle display, by setting the above-mentioned predetermined azimuth angle to the driver's side, it is possible to switch whether or not the image displayed on the display panel is visible when viewed from the driver's side. It is also preferable that the above-mentioned switching is controlled according to the driving state of the vehicle.
  • the present invention can also be preferably applied to image display devices for mobile applications (for example, laptop PCs, smartphones, tablet terminals, portable game consoles, etc.).
  • Example 1 A laminate was obtained in the following manner, and the image display device used in Example 1 was fabricated. [Preparation of Optical Film 1] An optical film 1 having a light absorptive anisotropic layer was prepared by the following procedure.
  • the following composition for forming an alignment film 1 was applied to the surface of a commercially available cellulose acylate film (manufactured by Fujifilm Corporation, product name Fujitac TG60UL) with a wire bar.
  • the support on which the coating film was formed was dried with hot air at 140° C. for 120 seconds to form an alignment film AL1, thereby obtaining an alignment film-attached cellulose acylate film 1.
  • the thickness of the alignment film AL1 was 1 ⁇ m.
  • composition for forming alignment film 1 Polymer PA-1 (listed below) 100.00 parts by weight Acid generator PAG-1 (listed below) 8.25 parts by weight Stabilizer DIPEA (listed below) 0.6 parts by weight Butyl acetate 1001.42 parts by weight Methyl ethyl ketone 250.36 parts by weight Club------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  • Polymer PA-1 (wherein the numerical value for each repeating unit represents the content (mass%) of each repeating unit relative to the total repeating units.)
  • composition P1 ⁇ 0.69 parts by mass of the dichroic substance D-1 shown below; 0.17 parts by mass of the dichroic substance D-2 shown below; 1.13 parts by mass of the dichroic substance D-3 shown below; Liquid crystal compound L-1 (8.67 parts by weight) (1.97 parts by weight) IRGACURE OXE-02 (manufactured by BASF) (0.20 parts by weight) Alignment agent E-1 (0.16 parts by weight) Agent E-2 0.16 parts by mass, surfactant F-2 (see below) 0.007 parts by mass, cyclopentanone 78.17 parts by mass, benzyl alcohol 8.69 parts by mass ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  • Liquid crystal compound L-1 [a mixture of the following liquid crystal compounds (RA), (RB) and (RC) in a mass ratio of 84:14:2]
  • Surfactant F-2 (In the following formula, TMS represents a trimethylsilyl group.)
  • the azimuth angle and polar angle of the central axis of transmittance of the laminated optical film 1 were examined by the following procedure. Using AxoScan OPMF-2 (manufactured by Axometrics), the transmittance was measured while changing the azimuth angle and polar angle at which light was incident on the laminated optical film 1, as described above, and the direction of the central axis of transmittance of the laminated optical film 1 was determined. The angle between the central axis of transmittance of the laminated optical film 1 (lightly absorptive anisotropic layer) and the normal line of the laminated optical film was 0°.
  • a polarizing plate having a polarizer thickness of 8 ⁇ m and one side of the polarizer (other optically absorptive anisotropic layer) exposed was prepared in the same manner as in the one-side protective film-attached polarizing plate 02 described in WO 2015/166991.
  • IPS liquid crystal cell 1 An IPS liquid crystal cell having a liquid crystal layer between two glass substrates was prepared.
  • a photo-alignment treatment was performed on the glass substrate with reference to Example 11 of JP-A-2005-351924 to form an alignment layer, and a liquid crystal layer in which the liquid crystal compound was aligned was formed in the liquid crystal cell.
  • the tilt angle of the liquid crystal compound with respect to the substrate surface was 0.1°.
  • the ⁇ n of the liquid crystal compound in the liquid crystal layer was 0.08625 at a wavelength of 550 nm, and the ⁇ nd was adjusted by adjusting the distance (gap; d) between the substrates.
  • the in-plane retardation of the liquid crystal cell 1 was 275 nm ( ⁇ /2).
  • the prepared optical compensation layer 1 was attached to one surface of the prepared IPS liquid crystal cell 1 using a commercially available adhesive (SK2057, manufactured by Soken Chemical Industries, Ltd.).
  • the prepared polarizing plate was attached using a commercially available adhesive SK2057 (manufactured by Soken Chemical & Engineering Co., Ltd.) so that the polarizer surface faced the surface of the optical compensation layer 1 opposite to the IPS liquid crystal cell 1 side.
  • the orientation relationship during attachment was adjusted so that the absorption axis of the polarizing plate and the slow axis of the optical compensation layer 1 were parallel to each other.
  • the prepared laminated optical film 1 was attached to the surface of the IPS liquid crystal cell opposite to the surface to which the polarizing plate was attached using a commercially available adhesive (SK2057, manufactured by Soken Chemical Industries, Ltd.), thereby obtaining a viewing angle control system 1.
  • the liquid crystal layer in the IPS liquid crystal cell 1 was set so that the angle between the in-plane slow axis of the liquid crystal layer when a voltage was applied and the absorption axis of the polarizing plate was 45°, and the angle between the in-plane slow axis of the liquid crystal layer when no voltage was applied and the absorption axis of the polarizing plate was 0°.
  • a Cosmoshine Super Birefringent Type (SRF, registered trademark, manufactured by Toyobo Co., Ltd.) (depolarizing film) was attached to the display screen of a dynabook (registered trademark, manufactured by Toshiba Corporation), a notebook computer equipped with a liquid crystal display device, using a commercially available adhesive SK2057 (manufactured by Soken Chemical Engineering Co., Ltd.).
  • the viewing angle control system 1 prepared above was placed on the depolarizing film to prepare an image display device A1 having a viewing angle control function.
  • the angle between the in-plane slow axis of the liquid crystal layer in the IPS liquid crystal cell 1 and the absorption axis of the polarizer could be switched between 45° and 0° by turning on and off the voltage applied to the IPS liquid crystal cell 1.
  • the up and down directions of the image display area of the above-mentioned notebook computer are set to an azimuth angle of 0°, it was confirmed that when the image display device A1 was viewed from an oblique direction at azimuth angles of 90° and 270°, it was possible to switch between light-shielding mode and transmissive mode by turning the voltage applied to the IPS liquid crystal cell 1 on and off.
  • Example 2 [Preparation of Optical Compensation Layer 2]
  • the film thickness, stretching temperature, and stretching ratio were adjusted to obtain a stretched film having an Re of 200 nm, an Rth of 100 nm, and an Nz factor of 1.0. This stretched film was designated as the optical compensation layer 2.
  • An image display device A2 was produced in the same manner as in Example 1, except that in the production of the viewing angle control system 1 in Example 1, the optical compensation layer 1 was changed to the above-mentioned optical compensation layer 2.
  • Example 3 Preparation of Optical Compensation Layer 3
  • the film thickness, the stretching temperature, and the stretching ratio were adjusted to obtain a stretched film having an Re of 65 nm, an Rth of 420 nm, and an Nz factor of 7.0. This stretched film was designated as the optical compensation layer 3.
  • the prepared optical compensation layer 3 was attached to one surface of the IPS liquid crystal cell 1 prepared in Example 1 using a commercially available adhesive (SK2057, manufactured by Soken Chemical Industries, Ltd.). Next, a laminated optical film 1 including the light absorption anisotropic layer prepared in Example 1 was bonded to the surface of the bonded optical compensation layer 3 opposite the IPS liquid crystal cell 1 side using a commercially available adhesive SK2057 (manufactured by Soken Chemical Industries, Ltd.).
  • the polarizing plate prepared in Example 1 was attached to the surface of the IPS liquid crystal cell 1 opposite to the surface to which the optical compensation layer 3 was attached, using a commercially available adhesive (SK2057, manufactured by Soken Chemical & Engineering Co., Ltd.), to prepare a viewing angle control system 3. At this time, the polarizing plate was attached so that the absorption axis of the polarizing plate and the slow axis of the optical compensation layer 3 were parallel to each other.
  • the liquid crystal layer in the IPS liquid crystal cell 1 was set so that the angle between the in-plane slow axis of the liquid crystal layer when a voltage was applied and the absorption axis of the polarizing plate was 45°, and the angle between the in-plane slow axis of the liquid crystal layer when no voltage was applied and the absorption axis of the polarizing plate was 0°.
  • An image display device A3 was produced in the same manner as in Example 1, except that the viewing angle control system 1 in Example 1 was changed to the viewing angle control system 3 described above.
  • Example 4 Preparation of Optical Compensation Layer 4
  • the film thickness, the stretching temperature, and the stretching ratio were adjusted to obtain a stretched film having an Re of 120 nm, an Rth of 420 nm, and an Nz factor of 4.0. This stretched film was designated as the optical compensation layer 4.
  • An image display device A4 was produced in the same manner as in Example 3, except that in the production of the viewing angle control system 3 of Example 3, the optical compensation layer 3 was changed to the above-mentioned optical compensation layer 4.
  • Example 5 Preparation of Optical Compensation Layer 5
  • the film thickness, the stretching temperature, and the stretching ratio were adjusted to obtain a stretched film having an Re of 50 nm, an Rth of 100 nm, and an Nz factor of 2.5. This stretched film was designated as the optical compensation layer 5.
  • IPS liquid crystal cell 5 was prepared in the same manner as in Example 1, except that in the preparation of the IPS liquid crystal cell 1 of Example 1, the distance between the substrates (gap; d) was adjusted so that the in-plane retardation of the liquid crystal layer was 140 nm ( ⁇ /4).
  • An image display device A5 was prepared in the same manner as in Example 1, except that in the preparation of the viewing angle control system 1 of Example 1, the optical compensation layer 1 was changed to the optical compensation layer 5 prepared above, and the IPS liquid crystal cell 1 was changed to the IPS liquid crystal cell 5 described above.
  • the angle between the in-plane slow axis of the liquid crystal layer in the IPS liquid crystal cell 5 and the absorption axis of the polarizer could be switched between 45° and 0° by turning on and off the voltage applied to the IPS liquid crystal cell 5.
  • Example 6 [Preparation of Optical Compensation Layer 6] The following composition for forming the optical compensation layer 6 was prepared to obtain a homogeneous solution.
  • ⁇ Composition for forming optical compensation layer 6 ⁇ - Discotic liquid crystal compound CA-1 80 parts by mass - Discotic liquid crystal compound CA-2 20 parts by mass - Discotic liquid crystal compound CB-1 5.6 parts by mass - Polymerizable monomer CS1 5.6 parts by mass - Polymer CC-1 0.2 parts by mass - Polymerization initiator (Irgacure 907, manufactured by BASF) 3 parts by mass - Toluene 170 parts by mass - Methyl ethyl ketone 73 parts by mass
  • Irgacure 907 manufactured by BASF
  • Discotic liquid crystal compound CA-1 (1,3,5-substituted benzene-type polymerizable discotic liquid crystal compound)
  • Discotic liquid crystal compound CA-2 (1,3,5-substituted benzene-type polymerizable discotic liquid crystal compound)
  • Discotic liquid crystal compound CB-1 polymerizable triphenylene type discotic liquid crystal compound
  • Polymer CC-1 (hereinafter, the copolymerization ratios in the chemical structural formulas are shown in mass%.)
  • a commercially available cellulose triacetate film (FUJITAC ZRD40, manufactured by FUJIFILM Corporation) was used after being subjected to a saponification treatment.
  • the above-mentioned composition for forming the optical compensation layer 6 was applied to the surface of the support, the solvent was dried in a process of continuously heating from room temperature to 100°C, and the coating film was further heated for about 90 seconds in a drying zone at 100°C. Thereafter, the temperature was lowered to 60°C, and then the coating film was cured by performing UV exposure of 300 mJ/ cm2 under the atmosphere to form a cured film.
  • the obtained laminate film of the cured film and the support had an Re of 3 nm, an Rth of 200 nm, and an Nz factor of 67.2.
  • the above laminate film was used as an optical compensation layer 6.
  • An image display device A6 was produced in the same manner as in Example 5, except that in the production of the viewing angle control system 5 of Example 5, the optical compensation layer 5 was changed to the above-mentioned optical compensation layer 6.
  • Example 7 Preparation of Optical Compensation Layer 7
  • the film thickness, stretching temperature, and stretching ratio were adjusted to obtain a stretched film having an Re of 75 nm, an Rth of 150 nm, and an Nz factor of 2.5. This stretched film was designated as the optical compensation layer 7.
  • IPS liquid crystal cell 7 was prepared in the same manner as in Example 1, except that in the preparation of the IPS liquid crystal cell 1 of Example 1, the distance between the substrates (gap; d) was adjusted so that the in-plane retardation of the liquid crystal layer was 400 nm.
  • An image display device A7 was prepared in the same manner as in Example 5, except that in the preparation of the viewing angle control system 5 of Example 5, the optical compensation layer 5 was changed to the above-mentioned optical compensation layer 7, and the IPS liquid crystal cell 5 was changed to the above-mentioned IPS liquid crystal cell 7.
  • Example 8 [Preparation of Optical Compensation Layer 8] A 40 ⁇ m thick cellulose acylate film (TAC substrate; Fujifilm Corporation, TG40) was subjected to a saponification treatment, and a composition for forming an optical compensation layer 8 prepared as shown in the table below was applied with a wire bar to form a coating film. The coating film was heated with hot air at 40° C. for 60 seconds to dry the solvent of the composition and to mature the alignment of the liquid crystal compound. Subsequently, in a nitrogen purged atmosphere (oxygen concentration 100 ppm), ultraviolet light was irradiated (300 mJ/cm 2 ) at 40° C. to fix the alignment of the liquid crystal compound and form a cured film. The obtained laminate film of the cured film and the support had an Re of 4 nm, an Rth of ⁇ 300 nm, and an Nz factor of ⁇ 74.5. The above laminate film was used as an optical compensation layer 8.
  • TAC substrate Fujifilm Corporation, TG40
  • composition for forming optical compensation layer 8 ⁇ 83 parts by mass of the following rod-shaped liquid crystal compound-1; 15 parts by mass of the following rod-shaped liquid crystal compound-2; 2 parts by mass of the following rod-shaped liquid crystal compound-3; 8 parts by mass of the following polymerizable monomer (M-1); and a polymerization initiator.
  • An image display device A8 was produced in the same manner as in Example 7, except that in the production of the viewing angle control system 7 of Example 7, the optical compensation layer 7 was changed to the above-mentioned optical compensation layer 8.
  • Example 9 [Preparation of Optical Compensation Layer 9]
  • the film thickness, the stretching temperature, and the stretching ratio were adjusted to obtain a stretched film having an Re of 75 nm, an Rth of 500 nm, and an Nz factor of 7.2. This stretched film was designated as the optical compensation layer 9.
  • IPS liquid crystal cell 9 was prepared in the same manner as in Example 1, except that in the preparation of the IPS liquid crystal cell 1 of Example 1, the angle between the in-plane slow axis of the liquid crystal layer when the voltage was ON and the in-plane slow axis when the voltage was OFF was set to 60°.
  • An image display device A9 was produced in the same manner as in Example 3, except that in the production of the image display device A3 in Example 3, the IPS liquid crystal cell 1 was changed to the above-mentioned IPS liquid crystal cell 9, and the optical compensation layer 3 was changed to the above-mentioned optical compensation layer 9.
  • the angle between the in-plane slow axis of the liquid crystal layer in the IPS liquid crystal cell and the absorption axis of the polarizer could be switched between 60° and 0° by turning on and off the voltage applied to the IPS liquid crystal cell 9.
  • Example 10 Preparation of Optical Compensation Layer 10
  • the film thickness, the stretching temperature, and the stretching ratio were adjusted to obtain a stretched film having an Re of 120 nm, an Rth of 420 nm, and an Nz factor of 4.0. This stretched film was designated as the optical compensation layer 10.
  • An image display device A10 was produced in the same manner as in Example 9, except that in the production of the viewing angle control system 9 of Example 9, the optical compensation layer 9 was changed to the above-mentioned optical compensation layer 10.
  • Example 11 Preparation of Optical Compensation Layer 11
  • the film thickness, the stretching temperature, and the stretching ratio were adjusted to obtain a stretched film having an Re of 200 nm, an Rth of 180 nm, and an Nz factor of 1.4. This stretched film was designated as the optical compensation layer 11.
  • IPS liquid crystal cell 11 An IPS liquid crystal cell 11 was prepared in the same manner as in Example 1, except that in the preparation of the IPS liquid crystal cell 1 of Example 1, the angle between the in-plane slow axis of the liquid crystal layer when the voltage is ON and the in-plane slow axis when the voltage is OFF was 25°.
  • An image display device A11 was produced in the same manner as in Example 5, except that in the production of the image display device A5 of Example 5, the IPS liquid crystal cell 5 was changed to the above-mentioned IPS liquid crystal cell 11, the optical compensation layer 5 was changed to the above-mentioned optical compensation layer 11, and the absorption axis of the polarizing plate and the slow axis of the optical compensation layer 11 were bonded so as to be perpendicular to each other.
  • the angle between the in-plane slow axis of the liquid crystal layer in the IPS liquid crystal cell and the absorption axis of the polarizer could be switched between 65° and 90° by turning on and off the voltage applied to the IPS liquid crystal cell.
  • the up and down directions of the image display area of the above-mentioned notebook computer are set to an azimuth angle of 0°, it was confirmed that when the image display device A11 was viewed from an oblique direction at azimuth angles of 90° and 270°, it was possible to switch between a light-blocking mode and a transmissive mode by turning the voltage applied to the IPS liquid crystal cell 11 on and off.
  • Example 12 Preparation of Optical Compensation Layer 12
  • the film thickness, the stretching temperature, and the stretching ratio were adjusted to obtain a stretched film having an Re of 150 nm, an Rth of 500 nm, and an Nz factor of 3.8. This stretched film was used as the optical compensation layer 12.
  • IPS liquid crystal cell 12 An IPS liquid crystal cell 12 was prepared in the same manner as in Example 1, except that in the preparation of the IPS liquid crystal cell 1 of Example 1, the distance between the substrates (gap; d) was adjusted so that the in-plane retardation of the liquid crystal layer was 350 nm, and the angle between the in-plane slow axis of the liquid crystal layer when the voltage was ON and the in-plane slow axis when the voltage was OFF was 65°.
  • An image display device A12 was produced in the same manner as in Example 5, except that in the production of the image display device A5 in Example 5, the IPS liquid crystal cell 5 was changed to the above-mentioned IPS liquid crystal cell 12, and the optical compensation layer 5 was changed to the above-mentioned optical compensation layer 12.
  • the angle between the in-plane slow axis of the liquid crystal layer in the IPS liquid crystal cell and the absorption axis of the polarizer could be switched between 65° and 0° by turning on and off the voltage applied to the IPS liquid crystal cell.
  • Example 13 [Preparation of Optical Compensation Layer 13]
  • the film thickness, the stretching temperature, and the stretching ratio were adjusted to obtain a stretched film having an Re of 150 nm, an Rth of 300 nm, and an Nz factor of 2.5. This stretched film was used as the optical compensation layer 13.
  • An image display device A13 was produced in the same manner as in Example 12, except that in the production of the viewing angle control system 12 of Example 12, the optical compensation layer 12 was changed to the above-mentioned optical compensation layer 13.
  • Example 14 [Preparation of Optical Compensation Layer 14]
  • the film thickness, the stretching temperature, and the stretching ratio were adjusted to obtain a stretched film having an Re of 200 nm, an Rth of 300 nm, and an Nz factor of 2.0. This stretched film was used as the optical compensation layer 14.
  • An image display device A14 was produced in the same manner as in Example 12, except that in the production of the viewing angle control system 12 of Example 12, the optical compensation layer 12 was changed to the above-mentioned optical compensation layer 14.
  • Example 15 Preparation of Optical Compensation Layer 15
  • the film thickness, the stretching temperature, and the stretching ratio were adjusted to obtain a stretched film having an Re of 200 nm, an Rth of 400 nm, and an Nz factor of 2.5. This stretched film was used as the optical compensation layer 15.
  • VA liquid crystal cell 13 The glass substrate with electrodes was immersed in a solution of household neutral detergent diluted with 50 cc of water for 30 seconds and allowed to dry naturally. In addition, an alignment film for liquid crystal material ("JALS-2021-R1", manufactured by JSR Corporation) was formed on a separately washed glass substrate, and the alignment film for liquid crystal material thus formed was subjected to a rubbing treatment. The glass substrate with electrodes and the glass substrate on which the alignment film was formed were assembled into a liquid crystal cell so that the rubbed surface was on the inside.
  • JALS-2021-R1 manufactured by JSR Corporation
  • the liquid crystal cell was produced by dropping and sealing a liquid crystal material having negative dielectric anisotropy ("MLC6608", manufactured by Merck) between the substrates, and forming a liquid crystal layer between the substrates so as to be vertically aligned. At this time, the cell gap between the substrates was adjusted so that ⁇ nd at a wavelength of 550 nm was adjusted to be 275 nm. By the above procedure, a VA mode liquid crystal cell, VA liquid crystal cell 13, was obtained. In VA liquid crystal cell 13, the alignment direction of the liquid crystal material (liquid crystal compound) was changed from vertical alignment to horizontal alignment by application of a voltage.
  • MLC6608 negative dielectric anisotropy
  • An image display device A15 was produced in the same manner as in Example 1, except that in the production of the image display device A1 of Example 1, the IPS liquid crystal cell 1 was changed to the above-mentioned VA liquid crystal cell 13, the optical compensation layer 1 was changed to the above-mentioned optical compensation layer 15, and the polarizing plate and the optical compensation layer 15 were laminated so that their absorption axis and slow axis were parallel to each other. In this case, the polarizing plate was laminated so that the angle between the alignment direction of the liquid crystal in the state where a voltage was applied to the VA liquid crystal cell 13 and the absorption axis of the polarizing plate was 45°.
  • the orientation direction of the liquid crystal compound changes by turning the voltage applied to the VA liquid crystal cell 13 ON (20 V) and OFF, making it possible to switch between a light-shielding mode (ON) and a transparent mode (OFF).
  • Example 16 [Preparation of Optical Compensation Layer 16]
  • the film thickness, the stretching temperature, and the stretching ratio were adjusted to obtain a stretched film having an Re of 200 nm, an Rth of 600 nm, and an Nz factor of 3.5. This stretched film was used as the optical compensation layer 16.
  • An image display device A16 was produced in the same manner as in Example 1, except that in the production of the image display device A3 of Example 3, the IPS liquid crystal cell 1 was changed to the above-mentioned VA liquid crystal cell 13, the optical compensation layer 3 was changed to the above-mentioned optical compensation layer 16, and the optical compensation layer 16 was laminated so that the absorption axis of the polarizing plate and the slow axis of the optical compensation layer 16 were perpendicular to each other. In this case, the polarizing plate was laminated so that the angle between the alignment direction of the liquid crystal in the state where a voltage was applied to the VA liquid crystal cell 13 and the absorption axis of the polarizing plate was 45°.
  • the orientation direction of the liquid crystal compound changes by turning the voltage applied to the VA liquid crystal cell 13 ON (20 V) and OFF, making it possible to switch between a light-shielding mode (ON) and a transparent mode (OFF).
  • ⁇ Example 17> [Preparation of Optical Compensation Layer 17-1] (Formation of Alignment Film 2) The following composition for forming an alignment film 2 was continuously applied to one side of a cellulose acylate film (TAC substrate; Fujifilm Corporation, TG40) having a thickness of 40 ⁇ m using a wire bar #14. The film was then dried with hot air at 60° C. for 60 seconds and then with hot air at 100° C. for 120 seconds.
  • TAC substrate Fujifilm Corporation, TG40
  • the above-prepared alignment film 2 was continuously subjected to a rubbing treatment.
  • the longitudinal direction of the long film was parallel to the transport direction, and the angle between the longitudinal direction of the film and the rotation axis of the rubbing roller was 90° (the film width direction was 0°, the film longitudinal direction was 90°, and when observed from the alignment film side, the clockwise direction with the film width direction as the reference is represented as a positive value, so the rotation axis of the rubbing roller is 0°).
  • the retardation layer coating solution A containing the discotic liquid crystal compound of the following composition was continuously applied to the above-prepared alignment film 2 with a wire bar to prepare the retardation layer A.
  • the film was heated with hot air at 130°C for 90 seconds, then with hot air at 100°C for 60 seconds, and then irradiated with UV at 80°C to fix the alignment of the liquid crystal compound.
  • the thickness of the retardation layer A was 1.0 ⁇ m, and the Re at 550 nm was 125 nm.
  • the average inclination angle of the disc surface of the discotic liquid crystal compound to the film surface was 90°, and it was confirmed that the discotic liquid crystal compound was aligned perpendicular to the film surface.
  • the angle of the slow axis of the retardation layer A was parallel to the rotation axis of the rubbing roller, and when the width direction of the film was 0° (the longitudinal direction was 90°), the slow axis was 0° when viewed from the retardation layer A side.
  • Optical compensation layer 17-2 was prepared in the same manner as in Example 8, except that in the preparation of optical compensation layer 8 in Example 8, the composition for forming optical compensation layer 8 was changed to the composition for forming optical compensation layer 17-2 described below, and the coating film thickness was adjusted so that Rth was ⁇ 90 nm.
  • composition for forming optical compensation layer 17-2 ⁇ the rod-shaped liquid crystal compound-1 83 parts by mass the rod-shaped liquid crystal compound-2 15 parts by mass the rod-shaped liquid crystal compound-3 2 parts by mass the polymerizable monomer (M-1) 8 parts by mass a polymerization initiator (Irgacure 127, manufactured by BASF) 2 parts by weight; polymerization initiator (Irgacure OXE01, manufactured by BASF) 4 parts by weight; the above surfactant F-1 0.62 parts by weight; the above surfactant F-2 0.82 parts by weight ⁇ 2 parts by mass of the above onium compound S01 ⁇ 5 parts by mass of the above polymer compound A-1 ⁇ Toluene 621 parts by mass ⁇ Methyl ethyl ketone 69 parts by mass ---------------------------------------------------------------------------------------------------------------------------------------------------------------
  • optical compensation layer 17 [Preparation of Optical Compensation Layer 17]
  • the optical compensation layer 17-1 and the optical compensation layer 17-2 produced by the above procedure were prepared, and were bonded together using a commercially available adhesive (SK2057, manufactured by Soken Chemical & Engineering Co., Ltd.) so that the coating layers faced each other, to produce the optical compensation layer 17.
  • the produced optical compensation layer 17 had Re of 125 nm, Rth of ⁇ 150 nm, and Nz factor of ⁇ 0.7.
  • An image display device A17 was produced in the same manner as in Example 16, except that in the production of the image display device A16 of Example 16, the optical compensation layer 16 was changed to the above-mentioned optical compensation layer 17, the optical compensation layer 17-1 layer included in the optical compensation layer 17 was arranged on the light absorption anisotropic layer 1 side, and the absorption axis of the polarizing plate and the slow axis of the optical compensation layer 17 were laminated so as to be perpendicular to each other.
  • the orientation direction of the liquid crystal compound changes by turning the voltage applied to the VA liquid crystal cell 13 ON (20 V) and OFF, making it possible to switch between a light-shielding mode (ON) and a transparent mode (OFF).
  • ECB liquid crystal cell 14 A polyimide film was provided as an alignment film on a glass substrate with an ITO electrode, and the alignment film was subjected to a rubbing treatment. The two obtained glass substrates were placed facing each other with the rubbing directions parallel to each other and bonded together. A liquid crystal material having positive dielectric anisotropy (MLC-9100 manufactured by Merck) was dripped and sealed between the upper and lower substrates to prepare a liquid crystal cell. At this time, the cell gap between the substrates was adjusted so that ⁇ nd at a wavelength of 550 nm was 275 nm. By the above procedure, an ECB liquid crystal cell 14, which is an ECB type liquid crystal cell, was obtained.
  • MLC-9100 positive dielectric anisotropy
  • An image display device A18 was produced in the same manner as in Example 17, except that the liquid crystal cell 13 in the image display device A17 of Example 17 was changed to a liquid crystal cell 14.
  • the alignment direction of the liquid crystal compound changes by turning the voltage applied to the ECB liquid crystal cell ON (10 V) and OFF, thereby making it possible to switch between a light-shielding mode (OFF) and a transmission mode (ON).
  • Example 19 [Preparation of Optical Compensation Layer 19]
  • the film thickness, the stretching temperature, and the stretching ratio were adjusted to obtain a stretched film having an Re of 150 nm, an Rth of 300 nm, and an Nz factor of 2.5. This stretched film was designated as the optical compensation layer 19.
  • a commercially available polyimide alignment film (SE-150, manufactured by Nissan Chemical Industries, Ltd.) was coated on a glass substrate with electrodes and heated for 1 hour at 250° C. This alignment film was divided into two regions by mask rubbing treatment, and a multi-domain alignment film was produced in which the rubbing axis was in the direction of 90° in region 1 and in the direction of 270° in region 2.
  • a coating solution was prepared by dissolving 100 parts by weight of the following discotic liquid crystal compound 1, 0.8 parts by weight of the following polymer compound 2, parts by weight of a photopolymerization initiator (Irgacure 907, manufactured by Ciba-Geigy Co., Ltd.), and parts by weight of a sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) in 200 parts by weight of methyl ethyl ketone.
  • This coating solution was spin-coated on the surface of the above-mentioned alignment film for multi-domain. This was heated for 2 minutes in a constant temperature zone at 120°C to orient the discotic liquid crystal compound.
  • VA liquid crystal cell 15 In the preparation of the VA liquid crystal cell 13 of Example 15, the substrate was the multi-domain substrate prepared above, and the distance between the substrates (gap; d) was adjusted so that the ⁇ nd of the liquid crystal layer was 700 nm. In the same manner as in Example 15, a VA liquid crystal cell 15 was prepared, except that the substrate was the multi-domain substrate prepared above, and the distance between the substrates (gap; d) was adjusted so that the ⁇ nd of the liquid crystal layer was 700 nm.
  • the alignment direction of the liquid crystal compound changes in the prepared image display device A19 by turning the voltage applied to the VA liquid crystal cell 15 ON (2.4 V) and OFF, and that the light-shielding mode (OFF) and the transmission mode (ON) can be switched.
  • Example 20 [Preparation of Optical Compensation Layer 20-1] An optical compensation layer 20-1 was prepared in the same manner as in Example 17, except that in the preparation of an optical compensation layer 17-1 of Example 17, the coating film thickness was adjusted so that Re was 150 nm and Rth was ⁇ 75 nm.
  • optical compensation layer 20 [Preparation of Optical Compensation Layer 20]
  • the optical compensation layer 20-1 and the optical compensation layer 8 prepared by the above procedure were prepared and bonded together using a commercially available adhesive (SK2057, manufactured by Soken Chemical & Engineering Co., Ltd.) so that the coating layers faced each other, to prepare the optical compensation layer 20.
  • the prepared optical compensation layer 17 had Re of 150 nm, Rth of ⁇ 375 nm, and Nz factor of ⁇ 2.0.
  • An image display device A20 was produced in the same manner as in Example 19, except that in the production of the image display device A19 of Example 19, the optical compensation layer 19 was changed to the above-mentioned optical compensation layer 120, the optical compensation layer 20-1 layer included in the optical compensation layer 20 was arranged on the liquid crystal cell 15 side, and the absorption axis of the polarizing plate and the slow axis of the optical compensation layer 17 were bonded at right angles to each other.
  • the orientation direction of the liquid crystal compound changes by turning the voltage applied to the VA liquid crystal cell 15 ON (2.4 V) and OFF, making it possible to switch between a light-shielding mode (OFF) and a transparent mode (ON).
  • Example 21 [Preparation of Optical Compensation Layer 21]
  • the film thickness, the stretching temperature, and the stretching ratio were adjusted to obtain a stretched film having an Re of 75 nm, an Rth of 125 nm, and an Nz factor of 2.2. This stretched film was used as the optical compensation layer 21.
  • An image display device A21 was produced in the same manner as in Example 16, except that in the preparation of the image display device A16 of Example 16, the optical compensation layer 16 was changed to the above-mentioned optical compensation layer 21, the liquid crystal cell 13 was changed to the liquid crystal cell 15, and the absorption axis of the polarizing plate and the slow axis of the optical compensation layer 17 were bonded so as to be perpendicular to each other.
  • the orientation direction of the liquid crystal compound changes by turning the voltage applied to the VA liquid crystal cell 15 ON (2.4 V) and OFF, making it possible to switch between a light-shielding mode (OFF) and a transmission mode (ON).
  • C The image is dark and difficult to recognize. In practical terms, an A or B rating is preferred.
  • A+ The image is bright and recognizable from any of the above angles.
  • the configuration of the image display device of each of the examples and comparative examples and the above evaluation results are shown in Tables 1 to 4.
  • the "switching angle" column of the liquid crystal cell indicates what angle the in-plane slow axis of the liquid crystal cell can be set to with respect to the absorption axis direction of the polarizer in the polarizing plate.

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WO2018003380A1 (ja) * 2016-06-30 2018-01-04 富士フイルム株式会社 光学装置および表示装置
KR20220069304A (ko) * 2020-11-20 2022-05-27 엘지디스플레이 주식회사 시야각 전환 표시장치

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018003380A1 (ja) * 2016-06-30 2018-01-04 富士フイルム株式会社 光学装置および表示装置
KR20220069304A (ko) * 2020-11-20 2022-05-27 엘지디스플레이 주식회사 시야각 전환 표시장치

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