Liquid crystal light control device

Abstract

This liquid crystal light control device includes a pair of substrates, a pair of alignment films between the pair of substrates, and a liquid crystal layer between the pair of alignment films. Each of the pair of substrates is provided with an electrode, and at least one of the pair of alignment films has a transmittance of 98% or more at a wavelength of 450 nm. Varnish for forming the alignment film contains a solid content and a solvent component, the solid content contains a coloring material, and the content ratio of the coloring material to the entire solid content may be less than 10 mol%.

Description

LCD light control device

[0001] An embodiment of the present invention relates to a liquid crystal light control device that controls the distribution of light emitted from a light source by utilizing the electro-optic effect of liquid crystals.

[0002] A technique for controlling the distribution of light emitted from a light source using a liquid crystal lens is known. For example, a pair of opposing substrates is provided with alignment films for orienting liquid crystals, and the alignment directions of the liquid crystals are orthogonal (twisted by 90°) (see Patent Document 1).

[0003] International Publication No. 2010 / 230887

[0004] Liquid crystal light control devices used for lighting are exposed to strong light, so if the alignment film is exposed to strong light for a long period of time, the alignment film itself will absorb the light, causing degradation due to the energy of the absorbed light.

[0005] Specifically, the deterioration of the alignment film weakens the ability of the alignment film to regulate the alignment of the liquid crystal, and when an electric field is applied to the liquid crystal to drive it and then the electric field is removed, the liquid crystal does not return to its initial alignment state, and the twist direction of the liquid crystal becomes locally reversed (reverse twist). As a result, the alignment of the liquid crystal is locally disturbed, and when light emitted from the light source passes through the liquid crystal with the disturbed alignment, it is scattered, resulting in the problem that the desired characteristics cannot be obtained when used as lighting.

[0006] In view of the above problems, one embodiment of the present invention has an object to provide a highly reliable liquid crystal light control device in which degradation of the alignment film is suppressed.

[0007] A liquid crystal light control device according to one embodiment of the present invention includes a pair of substrates, a pair of alignment films between the pair of substrates, and a liquid crystal layer between the pair of alignment films, each of the pair of substrates being provided with an electrode, and at least one of the pair of alignment films having a transmittance of 98% or more at a wavelength of 450 nm.

[0008] FIG. 1 shows an overview of a liquid crystal light control device according to one embodiment of the present invention. FIG. 2 shows a perspective view of a liquid crystal panel constituting a liquid crystal light control element according to one embodiment of the present invention. FIG. 3 shows an electrode structure of a liquid crystal panel constituting a liquid crystal light control element according to one embodiment of the present invention. FIG. 4 shows an electrode structure of a liquid crystal panel constituting a liquid crystal light control element according to one embodiment of the present invention. FIG. 5 is a diagram explaining the operation of a liquid crystal panel constituting a liquid crystal light control element according to one embodiment of the present invention. FIG. 6 is a diagram explaining the operation of a liquid crystal panel constituting a liquid crystal light control element according to one embodiment of the present invention. FIG. 7 is a diagram explaining the voltage applied to a liquid crystal panel constituting a liquid crystal light control element according to one embodiment of the present invention and the resulting state of light distribution control. FIG. 8 is a diagram explaining an example of light distribution control by a liquid crystal light control element according to one embodiment of the present invention. FIG. 9 is a diagram showing the absorption spectrum of an alignment film of Example 1. FIG. 10 is a diagram showing the absorption spectrum of an alignment film of Comparative Example 1.

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention can be implemented in many different forms, and should not be construed as being limited to the description of the embodiments exemplified below. For clarity of explanation, the drawings may show the width, thickness, shape, etc. of each part schematically compared to the actual form, but these are merely examples and do not limit the interpretation of the present invention. Furthermore, in this specification and each drawing, elements similar to those previously described with reference to the previous drawings are designated by the same reference numerals (or reference numerals with a, b, etc. suffixed thereto), and detailed descriptions may be omitted as appropriate. Furthermore, the letters "first" and "second" attached to each element are convenient labels used to distinguish each element and have no further meaning unless otherwise specified.

[0010] In this specification, when a component or region is referred to as being "on (or under)" another component or region, unless otherwise specified, this includes not only the case where it is directly above (or directly under) the other component or region, but also the case where it is above (or under) the other component or region, i.e., the case where another component is included between the component or region and above (or under) the other component or region.

[0011] In this specification, "light distribution" refers to the degree of spread of light emitted from a light source, i.e., the distribution of luminous intensity (light intensity) in each direction, in the usual sense, and controlling the light distribution means intentionally controlling the degree of spread of light emitted from a light source.

[0012] In this specification, "optical rotation" refers to the phenomenon in which the polarization axis of a linearly polarized component is rotated when passing through a liquid crystal layer.

[0013] In this specification, the "alignment direction" of an alignment film refers to the direction in which liquid crystal molecules are aligned when the alignment film is subjected to a treatment (e.g., a rubbing treatment or a photo-alignment treatment) that imparts an alignment restraining force to the alignment film and aligns the liquid crystal molecules on the alignment film. When the treatment performed on the alignment film is a rubbing treatment, the alignment direction of the alignment film is usually the rubbing direction. Alternatively, when the treatment performed on the alignment film is a treatment that utilizes a photoreaction using polarized ultraviolet light (e.g., a photo-alignment treatment), the alignment direction of the alignment film irradiated with polarized ultraviolet light is a direction perpendicular to the polarized light due to photolysis.

[0014] In this specification, the "extension direction" of a strip electrode refers to the direction in which the long side of a pattern having a short side (width) and a long side (length) extends when the strip electrode is viewed in a plan view.

[0015] 1. Overview of a Liquid Crystal Light Control Device Fig. 1 is a perspective view showing the configuration of a liquid crystal light control device 100 according to one embodiment of the present invention. Liquid crystal light control device 100 includes a liquid crystal light control element 102 and a control circuit 104. Liquid crystal light control element 102 is made up of multiple liquid crystal panels. Fig. 1 shows an example in which liquid crystal light control element 102 is made up of a first liquid crystal panel 1021, a second liquid crystal panel 1022, a third liquid crystal panel 1023, and a fourth liquid crystal panel 1024.

[0016] First liquid crystal panel 1021, second liquid crystal panel 1022, third liquid crystal panel 1023, and fourth liquid crystal panel 1024 are flat panels. Liquid crystal light control element 102 has a structure in which the flat surfaces of first liquid crystal panel 1021, second liquid crystal panel 1022, third liquid crystal panel 1023, and fourth liquid crystal panel 1024 are arranged so as to overlap each other. First liquid crystal panel 1021 and second liquid crystal panel 1022, second liquid crystal panel 1022 and third liquid crystal panel 1023, and third liquid crystal panel 1023 and fourth liquid crystal panel 1024 are bonded together with a transparent adhesive (not shown).

[0017] The liquid crystal light control element 102 is driven by a control circuit 104. In other words, control signals for driving each liquid crystal panel are output from the control circuit 104. As shown in Fig. 1, the control circuit 104 is connected to the first liquid crystal panel 1021 by a first flexible wiring board F1, to the second liquid crystal panel 1022 by a second flexible wiring board F2, to the third liquid crystal panel 1023 by a third flexible wiring board F3, and to the fourth liquid crystal panel 1024 by a fourth flexible wiring board F4.

[0018] The liquid crystal light control device 100 has a function of controlling the degree of spread of light emitted from the light source 106, i.e., the luminous intensity distribution of light spreading in a predetermined direction. The light source 106 is disposed on the rear side of the liquid crystal light control element 102. The light emitted from the light source 106 is emitted to the outside (illumination space) through the liquid crystal light control element 102. When the light emitted from the light source 106 is irradiated onto the liquid crystal light control element 102, the light passes through the first liquid crystal panel 1021, the second liquid crystal panel 1022, the third liquid crystal panel 1023, and the fourth liquid crystal panel 1024 in this order before being emitted to the outside.

[0019] There is no limitation on the configuration of the light source 106. The light source 106 is composed of components such as a light-emitting element, such as a light-emitting diode, a halogen lamp, a tungsten lamp, a mercury lamp, or a fluorescent lamp, and a reflector. The light source 106 may be a white light source, or a light source that emits dimmed light such as daylight white or warm white. An optical element such as a lens may be provided between the light source 106 and the liquid crystal light control element 102.

[0020] As will be described in detail below, the liquid crystal light control device 100 has a function of controlling the spread of light emitted from the light source 106 by the liquid crystal light control element 102. The liquid crystal light control element 102 has a function of forming a light distribution pattern such as a square, cross, or line shape on the irradiation surface with the light emitted from the light source 106, based on a control voltage output from the control circuit 104.

[0021] 2. Liquid Crystal Panel Figure 2 shows a perspective view of the first liquid crystal panel 1021 that constitutes the liquid crystal light control element 102. For the sake of explanation, Figure 2 shows the X, Y, and Z axis directions. The X and Y axes are orthogonal in a plan view, and the Z axis extends in a direction normal to the X-Y plane. In the following explanation, the X axis direction, Y axis direction, and Z axis direction are used to specify directions, but these expressions can also be replaced with expressions such as the X axis direction being the first direction, the Y axis direction being the second direction, and the Z axis direction being the third direction or the up-down direction.

[0022] The first liquid crystal panel 1021 includes a first substrate S11, a second substrate S12, a first electrode E11, a second electrode E12, a first alignment film AL11, a second alignment film AL12, and a first liquid crystal layer LC1. The first substrate S11 is provided with a first electrode E11 and a first alignment film AL11, and the second substrate S12 is provided with a second electrode E12 and a second alignment film AL12. The first alignment film AL11 is provided to cover the first electrode E11, and the second alignment film AL12 is provided to cover the second electrode E12. The first substrate S11 and the second substrate S12 are spaced apart from each other and arranged opposite each other. The first electrode E11 and the second electrode E12 are arranged on the inner surface of the first substrate S11 and the second substrate S12 facing each other. A first liquid crystal layer LC1 is provided between the first substrate S11 and the second substrate S12.

[0023] The first electrode E11 includes a first strip electrode E11A and a second strip electrode E11B each having a plurality of strip patterns. The second electrode E12 includes a third strip electrode E12A and a fourth strip electrode E12B each having a plurality of strip patterns. The first strip electrodes E11A and the second strip electrodes E11B are alternately arranged on the insulating surface of the first substrate S11, and the third strip electrodes E12A and the fourth strip electrodes E12B are alternately arranged on the insulating surface of the second substrate S12.

[0024] The longitudinal direction of the multiple strip patterns of the first strip electrode E11A and the second strip electrode E11B extends in the X-axis direction. The longitudinal direction of the multiple strip patterns of the third strip electrode E12A and the fourth strip electrode E12B extends in the Y-axis direction. Therefore, the direction in which the multiple strip patterns of the third strip electrode E12A and the fourth strip electrode E12B extend is orthogonal (intersects at 90 degrees) to the direction in which the multiple strip patterns of the first strip electrode E11A and the second strip electrode E11B extend. Note that the relative arrangement of the first strip electrode E11A and the second strip electrode E11B and the third strip electrode E12A and the fourth strip electrode E12B is not limited to being orthogonal, and may be changed within a range of ±10 degrees from 90 degrees.

[0025] Furthermore, the strip-shaped patterns of each of these strip-shaped electrodes may extend in a predetermined direction while being partially bent. In this case, the strip-shaped patterns have multiple extension directions in their longitudinal direction, and each extension direction may be inclined by approximately ±10 degrees with respect to the X-axis direction or the Y-axis direction. Similarly, the strip-shaped electrodes may have a configuration in which the strip-shaped patterns extend in a predetermined direction while being partially curved. In this case, the direction of the tangent at each position of the strip-shaped pattern is regarded as the extension direction, and each extension direction may be inclined by approximately ±10 degrees with respect to the X-axis direction or the Y-axis direction.

[0026] The direction in which the multiple strip patterns constituting the first strip electrode E11A and the second strip electrode E11B extend may be inclined in the range of 30±10 degrees to 60±10 degrees with respect to the X-axis direction. Similarly, the direction in which the multiple strip patterns constituting the third strip electrode E12A and the fourth strip electrode E12B extend may be inclined in the range of 30±10 degrees to 60±10 degrees with respect to the Y-axis direction.

[0027] The alignment direction ALD1 of the first alignment film AL11 is oriented in a direction (Y-axis direction) intersecting the extension direction of the first strip electrodes E11A and the second strip electrodes E11B, and the alignment direction ALD2 of the second alignment film AL12 is oriented in a direction (X-axis direction) intersecting the extension direction of the third strip electrodes E12A and the fourth strip electrodes E12B. The angle at which the extension direction of the first strip electrodes E11A and the second strip electrodes E11B intersects with the alignment direction ALD1 and the angle at which the extension direction of the third strip electrodes E12A and the fourth strip electrodes E12B intersects with the alignment direction ALD2 can be set within a range of 90±10 degrees.

[0028] The first substrate S11 and the second substrate S12 are disposed opposite each other with a gap of 10 μm or more. For example, the first substrate S11 and the second substrate S12 are disposed with a gap of 10 μm or more and 1000 μm or less, preferably 20 μm or more and 500 μm or less. A first liquid crystal layer LC1 provided between the first substrate S11 and the second substrate S12 has a thickness D. A first electrode E11, a second electrode E12, a first alignment film AL11, and a second alignment film AL12 are provided between the first substrate S11 and the second substrate S12, but the film thicknesses of these components are negligibly small compared to the gap between the first substrate S11 and the second substrate S12. Therefore, the gap between the first substrate S11 and the second substrate S12 can be considered the thickness D of the first liquid crystal layer LC1. That is, the thickness D of the first liquid crystal layer LC1 can be regarded as being 10 μm or more and 1000 μm or less, preferably 20 μm or more and 500 μm or less. Although not shown in FIG. 2, a spacer may be provided between the first substrate S11 and the second substrate S12.

[0029] The liquid crystal material forming the first liquid crystal layer LC1 is, for example, twisted nematic (TN) liquid crystal. As shown schematically in FIG. 2 , liquid crystal molecules have elongated rod-like structures due to their molecular structure. Liquid crystal molecules with rod-like structures have different physical properties in the long axis direction (parallel to the molecular long axis) and the short axis direction (perpendicular to the molecular long axis). Specifically, it is known that the difference in electrical properties is dielectric anisotropy, and the difference in optical properties is refractive index anisotropy. In liquid crystal displays, alignment films are provided to regularly align liquid crystal molecules with such physical properties. Similarly, the liquid crystal panel constituting the liquid crystal light control element 102 also has a first alignment film AL11 and a second alignment film AL12 to control the alignment direction of the liquid crystal molecules.

[0030] At least one of the first alignment film AL11 and the second alignment film AL12 has a transmittance of 98% or more at a wavelength of 450 nm. In this case, the thickness of at least one of the first alignment film AL11 and the second alignment film AL12 is preferably 20 nm or more and 200 nm or less, more preferably 40 nm or more and 150 nm or less. Because the first alignment film AL11 and the second alignment film AL12 have low absorption of high-energy short-wavelength light, when high-energy short-wavelength light is emitted from a light source, absorption of that light by the first alignment film AL11 and the second alignment film AL12 is minimized. Because the absorption of high-energy short-wavelength light by the first alignment film AL11 and the second alignment film AL12 is suppressed, deterioration of the first alignment film AL11 and the second alignment film AL12 is also suppressed, and a decrease in the ability of the first alignment film AL11 and the second alignment film AL12 to regulate the alignment of the liquid crystal can be prevented.

[0031] The first alignment film AL11 and the second alignment film AL12 can be obtained by applying polyamic acid or polyamic acid ester to a substrate, baking the resulting film, and then performing an alignment treatment. As described above, the alignment treatment of the first alignment film AL11 and the second alignment film AL12 is performed by rubbing or irradiation with polarized ultraviolet light. Next, we will explain the alignment film that undergoes the rubbing alignment treatment (rubbing treatment).

[0032] The alignment film for rubbing treatment can be formed from a varnish. The varnish can contain a solid component and a solvent component. The varnish can be composed of a solid component and a solvent component.

[0033] The solvent components include a good solvent and a coatability-improving solvent. The solvent components can be composed of a good solvent and a coatability-improving solvent. The good solvent is preferably contained in an amount of 50% by weight or more relative to the entire varnish of the alignment film, and the coatability-improving solvent is preferably contained in an amount of 10% by weight or more and 40% by weight or less relative to the entire varnish of the alignment film.

[0034] Specific examples of good solvents that can be used include N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 2-pyrrolidone, N-ethylpyrrolidone, N-vinylpyrrolidone, dimethyl sulfoxide, dimethyl sulfone, hexamethyl sulfoxide, γ-butyrolactone, 1,3-dimethyl-imidazolidinone, and 3-methoxy-N,N-dimethylpropanamide. Two or more of these may be mixed and used.

[0035] The coatability-improving solvent refers to, for example, a solvent having a lower surface tension than a good solvent. Specific examples of the coatability-improving solvent include ethyl cellosolve, ethyl cellosolve acetate, butyl cellosolve, butyl cellosolve acetate, ethyl carbitol, butyl carbitol, ethyl carbitol acetate, ethylene glycol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 1-butoxy-2-propanol, 1-phenoxy-2-propanol, propylene glycol monoacetate, propylene glycol diacetate, propylene glycol-1-monomethyl ether-2-acetate, propylene glycol-1-monoethyl ether-2-acetate, dipropylene glycol, 2-(2-ethoxypropoxy)propanol, methyl lactic acid ester, ethyl lactic acid ester, n-propyl lactic acid ester, n-butyl lactic acid ester, and isoamyl lactic acid ester. Two or more of these solvents may be used in combination.

[0036] The solid content of the varnish may be 0.5% by weight or more and 15% by weight or less, more preferably 2% by weight or more and 10% by weight or less, based on the total weight of the varnish.

[0037] The solid content may contain a coloring material in addition to the main component. However, the content of the coloring material relative to the total solid content is preferably less than 10 mol %. The lower the content of the coloring material relative to the total solid content, the higher the transmittance of the alignment film at a wavelength of 450 nm, and the more effectively the alignment film is prevented from deteriorating.

[0038] The main component is a polyamic acid or polyamic acid ester having a unit structure of the following chemical formula (1).

[0039] ...(1)

[0040] In the chemical formula (1), X １ is a tetravalent organic group. １ is a divalent organic group that does not contain atoms with an electronegativity of 3 or more, and R １ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and n is a positive integer.

[0041] R １ is selected from the viewpoint of the ease with which the imidization reaction of the polyamic acid or polyamic acid ester having the unit structure of chemical formula (1) proceeds when heated. １ is preferably a hydrogen atom, a methyl group, or an ethyl group, and more preferably a hydrogen atom or a methyl group.

[0042] X １ is a tetravalent organic group, and is, for example, a structure represented by the following structural formulas (X-1) to (X-22). In the following structural formulas (X-1) to (X-22), * represents X １ and the adjacent carbon (C).

[0043]

[0044] In the structural formulas (X-1) to (X-22), from the viewpoint of ease of availability of the compounds, X １ The structure of X １The structures of the structural formulae (X-9), (X-17), (X-18), (X-19), and (X-20) are preferred. Furthermore, in the structural formulae (X-1) to (X-22), from the viewpoint of obtaining an alignment film in which residual charges accumulated by a DC voltage applied between electrodes sandwiching a liquid crystal layer are quickly relaxed, X １ It is preferable to use a tetracarboxylic acid dianhydride having an aromatic ring structure, and structural formulas (X-18), (X-19), and (X-20) are more preferable.

[0045] Furthermore, X １ may be structures represented by the following structural formulas (X1-1) to (X1-4) in addition to the following structural formulas (X-1) to (X-22).

[0046]

[0047] In the structural formulas (X1-1) to (X1-4), from the viewpoint of the alignment of the liquid crystal molecules in the alignment film, R ３ From R ２３ is preferably a hydrogen atom, a halogen atom, a methyl group, or an ethyl group, and more preferably a hydrogen atom or a methyl group.

[0048] Specific examples of the structural formula (X1-1) include structures represented by the following structural formulas (X1-11) to (X1-16). * indicates X １ and the adjacent carbon (C).

[0049]

[0050] From the viewpoint of the alignment of liquid crystal molecules in the alignment film and the sensitivity of the photoreaction (the reaction rate of the photoreaction), the following structural formulae (X1-11), (X1-12) and (X1-12a) are particularly preferred.

[0051]

[0052] Y １ is a divalent organic group, and can be represented by the following chemical formula (2) or (3).

[0053] ...(2) ...(3)

[0054] In the chemical formula (2) and the chemical formula (3), A １ represents a single bond, an ester bond, an amide bond, a thioester bond, or a divalent organic group having 2 to 20 carbon atoms; A ２ is a hydrogen atom, a halogen atom, a hydroxyl group, an amino group, a thiol group, a nitro group, a phosphate group, or a monovalent organic group having 1 to 20 carbon atoms; a is an integer of 1 to 4; when a is 2 or more, A １ The structures of may be the same or different. b and c are each independently an integer of 1 to 2, and * represents Y １ and the adjacent nitrogen (N).

[0055] Y １ Specifically, the groups are represented by the following structural formulas (Y1-1) to (Y1-38), and * indicates that Y １ and the adjacent nitrogen (N).

[0056]

[0057]

[0058]

[0059] The coloring material is a polyamic acid or a polyamic acid ester having a unit structure of the following chemical formula (4).

[0060] ...(4)

[0061] In the chemical formula (4), X １ is a tetravalent organic group, and Y ２ is a divalent organic group having an atom with an electronegativity of 3 or more, and R １ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and n is a positive integer.

[0062] R １ Specifically, R in chemical formula (1) １ is the same as:

[0063] X １ Specifically, X in chemical formula (1) １ is the same as:

[0064] Y ２has an atom with an electronegativity of 3 or more. ２ is represented by the following chemical formula (5) or the following chemical formula (6).

[0065] ...(5) ...(6)

[0066] In the chemical formula (5) and the chemical formula (6), A １ represents a single bond, an ester bond, an amide bond, a thioester bond, or a divalent organic group having 2 to 20 carbon atoms; A ３ represents an atom having an electronegativity of 3 or more, a hydrogen atom, a halogen atom, a hydroxyl group, an amino group, a thiol group, a nitro group, a phosphate group, or a monovalent organic group having 1 to 20 carbon atoms; a represents an integer of 1 to 4; when a is 2 or more, A ３ are the same or different, b and c are each independently an integer of 1 to 2, and A ３ When is singular, A ３ is an atom with an electronegativity of 3 or more, and A ３ When there are a plurality of atoms, at least one of them is an atom with an electronegativity of 3 or more. ２ and the adjacent nitrogen (N).

[0067] A ３ The atom having an electronegativity of 3 or more in the formula (I) is preferably selected from nitrogen (N), oxygen (O), fluorine (F), and chlorine (Cl).

[0068] Y ２ Specifically, the structure containing an atom having an electronegativity of 3 or more is represented by the following structural formulas (Y2-1) to (Y2-42). In the following structural formulas (Y2-1) to (Y2-42), * indicates that Y ２ and the adjacent nitrogen (N).

[0069]

[0070]

[0071]

[0072]

[0073]

[0074]

[0075] Next, an alignment film that undergoes alignment treatment (photo-alignment treatment) by irradiation with polarized ultraviolet light will be described.

[0076] The alignment film for photo-alignment treatment can be formed from a varnish, similar to the alignment film for rubbing treatment, and the solvent components in the varnish are the same as those in the alignment film for rubbing treatment.

[0077] The solid content of the varnish includes a photodegradable component and a non-photodegradable component. The solid content of the varnish can be composed of a photodegradable component and a non-photodegradable component. The photodegradable component is an alignment component that aligns liquid crystal molecules by photooxidative decomposition due to irradiation with polarized ultraviolet light. The photodegradable component can be contained in the solid content in an amount of 20% by mass or more and 50% by mass or less relative to the total solid content. The non-photodegradable component can be contained in the solid content in an amount of 50% by mass or more and 80% by mass or less relative to the total solid content.

[0078] The solid content may contain a coloring material. The content ratio of the coloring material to all photodegradable components in the solid content is less than 10 mol %. The content ratio of the coloring material to all non-photodegradable components in the solid content is less than 10 mol %. The lower the content of the coloring material relative to the photodegradable components and non-photodegradable components, the higher the transmittance of the alignment film at a wavelength of 450 nm, and the more likely it is that degradation of the alignment film will be suppressed.

[0079] The photodegradable component is also a component with high transmittance in the visible light region, and is a polyamic acid or polyamic acid ester having a unit structure represented by the following chemical formula (7).

[0080] ... (7)

[0081] In the chemical formula (7), X ２ is represented by the following structural formulas (X2-1) to (X2-4), and Y ３ is a divalent organic group, and R １ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and n is a positive integer.

[0082]

[0083] In structural formulas (X2-1) to (X2-4), R ３ ~R ２３ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms and containing a fluorine atom, or a phenyl group, and may be the same or different. ２ and the adjacent carbon (C).

[0084] In the structural formulas (X2-1) to (X2-4), from the viewpoint of the alignment of the liquid crystal molecules in the alignment film, R ３ From R ２３ is preferably a hydrogen atom, a halogen atom, a methyl group, or an ethyl group, and more preferably a hydrogen atom or a methyl group.

[0085] Specific examples of the structural formula (X2-1) include structures represented by the following structural formulas (X2-11) to (X2-16). * indicates X ２ and the adjacent carbon (C).

[0086]

[0087] From the viewpoint of the alignment of the liquid crystal molecules in the alignment film and the sensitivity of the photoreaction, the following structural formulae (X2-11), (X2-12) and (X2-12a) are particularly preferred.

[0088]

[0089] In the chemical formula (7), Y ３ may be represented by the following chemical formula (8) or the following chemical formula (9).

[0090] ...(8)

[0091] ...(9)

[0092] In the chemical formula (8) and the chemical formula (9), A １ represents a single bond, an ester bond, an amide bond, a thioester bond, or a divalent organic group having 2 to 20 carbon atoms; A ３represents an atom with an electronegativity of 3 or more, a hydrogen atom, a halogen atom, a hydroxyl group, an amino group, a thiol group, a nitro group, a phosphate group, or a monovalent organic group having 1 to 20 carbon atoms; a represents an integer of 1 to 4; and b and c each independently represent an integer of 1 or 2. * represents Y ３ and the adjacent nitrogen (N).

[0093] Y ３ can be represented by, for example, the above structural formulas (Y1-1) to (Y1-38) and (Y2-1) to (Y2-42).

[0094] R １ is preferably a hydrogen atom, a methyl group, or an ethyl group, more preferably a hydrogen atom or a methyl group, from the viewpoint of ease of progress of the imidization reaction when the polyamic acid or polyamic acid ester having the unit structure of chemical formula (7) is heated.

[0095] The coloring material contained in the photodecomposition component is a polyamic acid or polyamic acid ester having a unit structure of the following chemical formula (10).

[0096] ...(10)

[0097] In the chemical formula (10), X ２ is X in the above-mentioned chemical formula (7). ２ and Y ２ , and R １ represents Y in the above-mentioned chemical formula (4). ２ , and R １ is the same as:

[0098] The non-photodecomposable component is a polyamic acid or polyamic acid ester having a unit structure of the following chemical formula (11).

[0099] ...(11)

[0100] In the chemical formula (11), X ３ is represented by the following structural formulas (X3-1) to (X3-22), and Y ３ and R １ is Y in chemical formula (7) ３ and R １In the following structural formulas (X3-1) to (X3-22), * indicates X ３ is the bonding position to the adjacent carbon (C).

[0101]

[0102]

[0103] In the structural formulas (X3-1) to (X3-22), from the viewpoint of ease of availability of the compounds, X ３ The structures of the structural formulae (X3-9), (X3-17), (X3-18), (X3-19), and (X3-20) are preferred. Furthermore, in the structural formulae (X3-1) to (X3-22), from the viewpoint of obtaining an alignment film in which residual charges accumulated by a DC voltage applied between electrodes sandwiching a liquid crystal layer are quickly relaxed, X ３ It is preferable to use a tetracarboxylic acid dianhydride having an aromatic ring structure, and structural formulas (X3-18), (X3-19), and (X3-20) are more preferable.

[0104] The coloring material contained in the non-photodecomposable component is a polyamic acid or a polyamic acid ester having a unit structure of the above chemical formula (8) or (9).

[0105] By using the above-described alignment film, the alignment film of this embodiment is prevented from deteriorating and makes it possible to control the alignment direction of liquid crystal molecules.

[0106] FIG. 3A shows a plan view of the first substrate S11, and FIG. 3B shows a plan view of the second substrate S12. As shown in FIG. 3A, the first electrode E11 has a structure in which a plurality of first strip electrodes E11A and a plurality of second strip electrodes E11B are alternately arranged. The longitudinal directions of the plurality of first strip electrodes E11A and the plurality of second strip electrodes E11B extend in the X-axis direction. In contrast, the alignment direction of the first alignment film AL11 (not shown) extends in the Y-axis direction. That is, the longitudinal extension direction of the plurality of first strip electrodes E11A and the plurality of second strip electrodes E11B intersects (is perpendicular to) the alignment direction. Furthermore, as shown in FIG. 3B, the second electrode E12 has a structure in which a plurality of third strip electrodes E12A and a plurality of fourth strip electrodes E12B are alternately arranged. The longitudinal direction of the plurality of third strip electrodes E12A and the plurality of fourth strip electrodes E12B extends in the Y-axis direction. In contrast, the alignment direction of the second alignment film AL12 (not shown) extends in the X-axis direction. That is, the longitudinal extension direction of the plurality of third strip electrodes E12A and the plurality of fourth strip electrodes E12B intersects (is perpendicular to) the alignment direction.

[0107] As shown in FIG. 3A , the plurality of first strip-shaped electrodes E11A are each connected to a first power supply line PE11, and the plurality of second strip-shaped electrodes E11B are each connected to a second power supply line PE12. The first power supply line PE11 is connected to a first connection terminal T11, and the second power supply line PE12 is connected to a second connection terminal T12. The first connection terminal T11 and the second connection terminal T12 are provided at an end of the first substrate S11. The first substrate S11 is provided with a third connection terminal T13 adjacent to the first connection terminal T11 and a fourth connection terminal T14 adjacent to the second connection terminal T12. The third connection terminal T13 is connected to a fifth power supply line PE15. The fifth power supply line PE15 is connected to a first power supply terminal PT11 provided on the first substrate S11. The fourth connection terminal T14 is connected to a sixth power supply line PE16. The sixth power supply line PE16 is connected to a second power supply terminal PT12 provided on the first substrate S11.

[0108] The same voltage is applied to the multiple first strip electrodes E11A via the first power supply line PE11. The same voltage is applied to the multiple second strip electrodes E11B via the second power supply line PE12. When different voltages are applied to the first connection terminal T11 and the second connection terminal T12, a potential difference occurs between the multiple first strip electrodes E11A and the multiple second strip electrodes E11B, generating an electric field. As a result, an electric field is generated in the horizontal direction (Y-axis direction) by the multiple first strip electrodes E11A and the multiple second strip electrodes E11B.

[0109] As shown in FIG. 3B , the plurality of third strip-shaped electrodes E12A are each connected to a third power supply line PE13, and the plurality of fourth strip-shaped electrodes E12B are each connected to a fourth power supply line PE14. The third power supply line PE13 is connected to a third power supply terminal PT13, and the fourth power supply line PE14 is connected to a fourth power supply terminal PT14. The third power supply terminal PT13 is provided at a position corresponding to the first power supply terminal PT11 on the first substrate S11, and the fourth power supply terminal PT14 is provided at a position corresponding to the second power supply terminal PT12 on the first substrate S11. The third power supply terminal PT13 and the first power supply terminal PT11, and the fourth power supply terminal PT14 and the second power supply terminal PT12 are electrically connected. A conductive paste is used for the electrical connection between these power supply terminals. For example, a silver paste is used as the conductive paste.

[0110] When different voltages are applied to the third connection terminal T13 and the fourth connection terminal T14, a potential difference occurs between the third strip electrodes E12A and the fourth strip electrodes E12B, generating an electric field in the horizontal direction (X-axis direction) due to the third strip electrodes E12A and the fourth strip electrodes E12B.

[0111] The first substrate S11 and the second substrate S12 are light-transmitting substrates, such as a glass substrate or a resin substrate. The first electrode E11 and the second electrode E12 are transparent electrodes formed of indium tin oxide (ITO) or indium zinc oxide (IZO). The power supply lines (first power supply line PE11, second power supply line PE12, third power supply line PE13, and fourth power supply line PE14) and connection terminals (first connection terminal T11, second connection terminal T12, third connection terminal T13, and fourth connection terminal T14) are formed of metal materials such as aluminum, titanium, molybdenum, and tungsten. Note that the power supply lines (first power supply line PE11, second power supply line PE12, third power supply line PE13, and fourth power supply line PE14) may be formed of the same transparent conductive film as the first electrode E11 and the second electrode E12. Of course, it is also possible to employ a configuration in which either or both of the first electrode E11 and the second electrode E12 are formed from a metal material or a transparent conductive film having a metal material laminated thereon.

[0112] The width WE of the first strip electrode E11A, the second strip electrode E11B, the third strip electrode E12A, and the fourth strip electrode E12B is preferably 5 μm or more. By having each strip electrode have a width of 5 μm or more, resistance loss can be reduced and a uniform horizontal electric field can be formed in the plane, even if each strip electrode is formed of a transparent conductive film as described above. For the same reason, the widths of the first power supply line PE11, the second power supply line PE12, the third power supply line PE13, and the fourth power supply line PE14 are also preferably 5 μm or more.

[0113] 4A and 4B are diagrams for explaining the operation of the first liquid crystal panel 1021, and show the structure of the first liquid crystal panel 1021 shown in Fig. 2 when viewed from the XA side. Fig. 4A shows a state in which no voltage is applied to the first electrode E11 (first strip electrode E11A and second strip electrode E11B), and Fig. 4B shows a state in which a voltage is applied to the first electrode E11 and a transverse electric field is generated between the first strip electrode E11A and the second strip electrode E11B.

[0114] The first strip-shaped electrode E11A and the second strip-shaped electrode E11B are arranged with a distance WD between them, with the longitudinal direction of the strip-shaped pattern extending in the X-axis direction. Comparing the thickness D of the first liquid crystal layer LC1 with the electrode distance WD between the first electrodes E11, the thickness D of the first liquid crystal layer LC1 is equal to or greater than the electrode distance WD (D≧WD). For example, the thickness D of the first liquid crystal layer LC1 is at least twice the electrode distance WD between the first electrodes E11. For example, when the thickness D of the first liquid crystal layer LC1 is 10 μm, the electrode distance WD can be 5 μm, and when the thickness D of the first liquid crystal layer LC1 is 50 μm, the electrode distance WD can be 10 μm.

[0115] The alignment direction of the first alignment film AL11 extends in the Y-axis direction, and the alignment direction of the second alignment film AL12 extends in the X-axis direction. When no electric field is applied to the first liquid crystal layer LC1 ( FIG. 4A ), the long axes of the liquid crystal molecules LCM are aligned with a 90-degree twist from the first substrate S11 side to the second substrate S12 side. In this state, the first liquid crystal layer LC1 has a uniform refractive index distribution. When light is incident on the first liquid crystal panel 1021, the polarized components of the incident light are rotated by the twist of the liquid crystal molecules LCM. In this state, the incident light is rotated but passes through the first liquid crystal layer LC1 without being refracted (or scattered).

[0116] On the other hand, when a voltage is applied to the first electrode E11 and a transverse electric field is generated between the first strip electrode E11A and the second strip electrode E11B, the long axes of the liquid crystal molecules LCM are oriented along the electric field (if the liquid crystal has positive dielectric anisotropy). As a result, as shown in FIG. 4B , regions are formed in which the liquid crystal molecules LCM stand above the first strip electrode E11A and the second strip electrode E11B, and regions are formed between the first strip electrode E11A and the second strip electrode E11B in which the liquid crystal molecules LCM are oriented obliquely along the distribution of the electric field. At this time, if the thickness D of the first liquid crystal layer LC1 is sufficiently large (10 μm or more), i.e., if the thickness D of the first liquid crystal layer LC1 is sufficiently large, the electric field generated by the first electrode E11 does not affect the second substrate S12 side, and the alignment state of the liquid crystal molecules LCM changes only on the first substrate S11 side. In other words, the liquid crystal molecules LCM on the second substrate S12 side are not affected by the electric field and maintain an unchanged alignment.

[0117] As shown in FIG. 4B , when a transverse electric field is generated between the first strip electrode E11A and the second strip electrode E11B, the liquid crystal molecules LCM are oriented such that their long axes are aligned in a convex arc shape along the direction of the electric field. In liquid crystals with refractive index anisotropy, the refractive index distribution also changes to an arc shape as the alignment state of the liquid crystal molecules LCM changes. When light is incident from the first substrate S11 in this state, the polarized component parallel to the Y-axis direction is diffused radially due to the refractive index distribution. Meanwhile, the polarized component parallel to the X-axis direction is not affected by the refractive index distribution and enters the first liquid crystal layer LC1 without being diffused. In this way, by aligning the liquid crystal molecules LCM in a specific direction and changing their alignment state using a transverse electric field, it is possible to diffuse a specific polarized component of the incident light (widening the luminous intensity distribution).

[0118] 4A and 4B illustrate the effect of the first electrode E11 on the liquid crystal molecules LCM and incident light, but the same applies to the effect that the second electrode E12 of the second substrate S12 has on the first liquid crystal layer LC1. That is, on the second substrate S12 side, the second electrode E12 generates a transverse electric field, which can diffuse the polarized light component parallel to the X-axis direction (widen the luminous intensity distribution).

[0119] As described with reference to FIGS. 4A and 4B , the first liquid crystal panel 1021 can diffuse incident light in a predetermined direction. Therefore, the use of the first liquid crystal panel 1021 makes it possible to control the light distribution state of light emitted from a light source. However, when strong light is irradiated onto the alignment films (first alignment film AL11, second alignment film AL12), the alignment films may be deteriorated due to the influence of that light. This influence can be particularly significant for alignment films formed from organic materials such as polyimides. Even in liquid crystal displays, the alignment films are exposed to backlight light, but the luminous intensity is lower than that of a light source for illumination, and high-energy, short-wavelength light is absorbed by the polarizer, so alignment film deterioration is not a problem. On the other hand, when used for illumination purposes such as the liquid crystal light control element 102 of this embodiment and strong light is incident from a light source, the alignment films are prone to deterioration.

[0120] When the alignment film deteriorates, the alignment control force for the liquid crystal molecules LCM decreases, which causes a problem. When the alignment control force decreases, the direction in which the liquid crystal molecules LCM twist becomes unstable, and when the applied voltage is turned off and the electric field is removed, a phenomenon occurs in which the twist direction is reversed (hereinafter also referred to as "reverse twist"), causing the alignment of the liquid crystal molecules LCM to become unstable.

[0121] To cope with this phenomenon, the occurrence of reverse twist can be suppressed by using an alignment film having a transmittance of 98% or more at a wavelength of 450 nm as in this embodiment.

[0122] 5 shows the first liquid crystal panel 1021, in which the first strip electrode E11A and the second strip electrode E11B of the first electrode E11 extend in the X-axis direction, and the third strip electrode E12A and the fourth strip electrode E12B of the second electrode E12 extend in the Y-axis direction. The alignment direction of the first alignment film AL1 is parallel to the Y-axis direction, and the alignment direction of the second alignment film AL2 is parallel to the X-axis direction. Therefore, the long axes of the liquid crystal molecules LCM on the first substrate S11 side are oriented in the Y-axis direction, and the long axes of the liquid crystal molecules LCM on the second substrate S12 side are oriented in the X-axis direction.

[0123] FIG. 5 also shows a state in which the control circuit 104 applies a high-level voltage VH to the first strip electrode E11A, a low-level voltage VL (VH>VL) to the second strip electrode E11B, a high-level voltage VH to the third strip electrode E12A, and a low-level voltage VL (VH>VL) to the fourth strip electrode E12B.

[0124] Light emitted from the light source has a first polarization component PL1 and a second polarization component PL2, and is incident on the first liquid crystal panel 1021 from the first substrate S11 side. Here, the first polarization component PL1 corresponds to a P wave (having an amplitude in the X-axis direction), and the second polarization component PL2 corresponds to an S wave (having an amplitude in the Y-axis direction). As shown in the table inserted in Fig. 5 , the light incident on the first liquid crystal panel 1021 is subjected to optical effects such as transmission, optical rotation, and diffusion by the first liquid crystal layer LC1.

[0125] Here, "Transmission" in the table refers to the transmission of a given polarization component without changing its polarization axis or light distribution. Furthermore, "Diffusion (Y)" indicates that the polarization component is diffused in a direction parallel to the Y-axis. Although not shown in Figure 5, "Diffusion (X)" indicates that the polarization component is diffused in a direction parallel to the X-axis.

[0126] Because the first polarized component PL1 is a P-wave, its polarization direction intersects with the long axis direction of the liquid crystal molecules LCM on the first electrode E11 side, and it is transmitted as is without being affected by the arc-shaped refractive index distribution formed by the orientation of the liquid crystal molecules LCM. As the first polarized component PL1 travels through the first liquid crystal layer LC1 from the first substrate S11 side to the second substrate S12 side, it is rotated by 90 degrees and transitions to an S-wave state. The polarization direction of the first polarized component PL1 that has transitioned to an S-wave state intersects with the long axis direction of the liquid crystal molecules LCM on the second electrode E12 side, and it is transmitted as is without being affected by the arc-shaped refractive index distribution formed by the orientation of the liquid crystal molecules LCM.

[0127] On the other hand, the second polarized component PL2 is an S-wave, and because its polarization direction on the first electrode E11 side is parallel to the long axis direction of the liquid crystal molecules LCM, it is diffused in the Y-axis direction due to the influence of the arc-shaped refractive index distribution formed by the orientation of the liquid crystal molecules LCM. As the second polarized component PL2 travels through the first liquid crystal layer LC1 from the first substrate S11 side to the second substrate S12 side, it is rotated by 90 degrees and transitions to a P-wave state. Because the polarization direction of the second polarized component PL2 on the second electrode E12 side becomes parallel to the long axis direction of the liquid crystal molecules LCM, it is diffused in the X-axis direction due to the influence of the arc-shaped refractive index distribution formed by the orientation of the liquid crystal molecules LCM.

[0128] In this way, when light enters the first liquid crystal panel 1021 from the first substrate S11 side, the first polarization component PL1 (P wave) is not diffused, but is rotated by the first liquid crystal layer LC1 and emitted in the form of an S wave, and the second polarization component PL2 (S wave) is diffused once in each of the Y-axis direction and the X-axis direction, and is rotated by the first liquid crystal layer LC1 and emitted in the form of a P wave.

[0129] Figure 5 shows an example in which the second polarization component PL2 (S wave) is diffused in the Y-axis and X-axis directions by the first liquid crystal panel 1021, but it is also possible to diffuse the first polarization component PL1 (P wave) by combining multiple liquid crystal panels.

[0130] 4. Operation of Liquid Crystal Light Control Element Figure 6 shows an example of the operation of liquid crystal light control element 102. As explained with reference to Figure 1, liquid crystal light control element 102 is composed of four liquid crystal panels (first liquid crystal panel 1021, second liquid crystal panel 1022, third liquid crystal panel 1023, and fourth liquid crystal panel 1024) having a configuration similar to that of first liquid crystal panel 1021. For the sake of explanation, Figure 6 shows the liquid crystal panels arranged separately, but in actual liquid crystal light control element 102, the liquid crystal panels are bonded together with a light-transmitting adhesive.

[0131] The second liquid crystal panel 1022, the third liquid crystal panel 1023, and the fourth liquid crystal panel 1024 have the same configuration as the first liquid crystal panel 1021 shown in Fig. 5. That is, the second liquid crystal panel 20 has a first substrate S21, a second substrate S22, a first electrode E21, a second electrode E22, and a second liquid crystal layer LC2. The third liquid crystal panel 30 has a first substrate S31, a second substrate S32, a first electrode E31, a second electrode E32, and a third liquid crystal layer LC3. The fourth liquid crystal panel 40 has a first substrate S41, a second substrate S42, a first electrode E41, a second electrode E42, and a fourth liquid crystal layer LC4. Note that for simplicity, the alignment films of each liquid crystal panel are omitted from the illustration in Fig. 6.

[0132] The first electrodes E11, E21, E31, E41 are composed of first strip electrodes E11A, E21A, E31A, E41A and second strip electrodes E11B, E21B, E31B, E41B, and these strip electrodes extend in the X-axis direction, and the second electrodes E12, E22, E32, E42 are composed of third strip electrodes E12A, E22A, E32A, E42A and fourth strip electrodes E12B, E22B, E32B, E42B, and these strip electrodes extend in the Y-axis direction.

[0133] A low-level voltage VL, a high-level voltage VH, and a constant voltage CV are applied to each liquid crystal panel as control signals. The low-level voltage VL is, for example, 0 V or -15 V, and the high-level voltage VH is, for example, 30 V (for VL = 0 V) ​​or 15 V (for VL = -15 V). The constant voltage CV is, for example, a voltage signal that is an intermediate voltage between VL and VH, or 0 V (ground).

[0134] 6 shows a state in which a high-level voltage VH and a low-level voltage VL are applied as control signals to the first electrode E11 and the second electrode E12 of the first liquid crystal panel 1021, the first electrode E21 and the second electrode E22 of the second liquid crystal panel 1022, the first electrode E31 and the second electrode E32 of the third liquid crystal panel 1023, and the first electrode E41 and the second electrode E42 of the fourth liquid crystal panel 1024. That is, the liquid crystal molecules are aligned by a transverse electric field on the first substrates S11, S21, S31, S41 side and the second substrates S12, S22, S32, S42 side of each liquid crystal panel.

[0135] 6 shows that light emitted from the light source enters the first liquid crystal panel 1021 and exits the fourth liquid crystal panel 1024. The light emitted from the light source includes a first polarized component PL1 (P wave) and a second polarized component PL2 (S wave), and the table inserted in FIG. 6 shows how the diffusion, optical rotation, and transmission change at each liquid crystal panel.

[0136] Of the light incident on the first liquid crystal panel 1021, the first polarization component PL1 (P wave) is transmitted through the first electrode E11 side, rotated by the first liquid crystal layer LC1 and transitioned to an S wave, and transmitted through the second electrode E12 side to be emitted, while the second polarization component PL2 (S wave) is diffused in the Y-axis direction on the first electrode E11 side, rotated by the first liquid crystal layer LC1 and transitioned to a P wave, and diffused in the X-axis direction on the second electrode E12 side to be emitted. In this way, the polarization states of the first polarization component PL1 and the second polarization component PL2 change as they pass through the first liquid crystal panel 1021, and the second polarization component PL2 is diffused in the Y-axis and X-axis directions to be emitted.

[0137] A similar phenomenon occurs at the second liquid crystal panel 1022, the third liquid crystal panel 1023, and the fourth liquid crystal panel 1024. That is, the polarization state of the first polarized component PL1 and the second polarized component PL2 incident on the second liquid crystal panel 1022 changes as they pass through the second liquid crystal panel 1022, and the first polarized component PL1 is diffused in the Y-axis and X-axis directions before being emitted. The polarization state of the first polarized component PL1 and the second polarized component PL2 incident on the third liquid crystal panel 1023 changes as they pass through the third liquid crystal panel 1023, and the second polarized component PL2 is diffused in the Y-axis and X-axis directions before being emitted. Then, the polarization state of the first polarized component PL1 and the second polarized component PL2 incident on the fourth liquid crystal panel 1024 changes as they pass through the fourth liquid crystal panel 1024, and the first polarized component PL1 is diffused in the Y-axis and X-axis directions before being emitted.

[0138] In this way, the first polarization component (P wave) of the light emitted from the light source is diffused twice in the Y-axis direction and twice in the X-axis direction as it passes through the first liquid crystal panel 1021 to the fourth liquid crystal panel 1024, and the second polarization component (S wave) is also diffused twice in the Y-axis direction and twice in the X-axis direction as it passes through the first liquid crystal panel 1021 to the fourth liquid crystal panel 1024. In other words, the first polarization component PL1 and the second polarization component PL2 are diffused evenly in the X-axis direction and the Y-axis direction, so that a rectangular light distribution pattern can be formed.

[0139] Note that the voltage application conditions shown in FIG. 6 are merely examples, and various alignment patterns can be formed by combining different voltage application conditions. For example, a line-shaped light distribution pattern can be formed by applying a voltage application pattern that diffuses the first polarization component PL1 (P wave) and the second polarization component PL2 (S wave) only in the X-axis direction or the Y-axis direction. Furthermore, a cross-shaped light distribution pattern can be formed by applying a voltage application pattern that diffuses the P-wave polarization component in the X-axis direction and the S-wave polarization component in the Y-axis direction for the first polarization component PL1 (P wave) and the second polarization component PL2 (S wave). The number of liquid crystal panels constituting the liquid crystal light control element 102 is not limited to four and can be increased. Furthermore, the overlapping manner of each liquid crystal panel can be varied. For example, the upper liquid crystal panel can be rotated at a predetermined angle relative to the lower liquid crystal panel.

[0140] In the liquid crystal light control element 102 that can be configured and operated in this way, by using an alignment film with a transmittance of 98% or more at a wavelength of 450 nm, deterioration of the alignment film is suppressed even when strong light is incident from the light source, and therefore alignment disturbance in the liquid crystal layer can be suppressed, thereby improving the reliability of the liquid crystal light control device 100.

[0141] The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples and various modifications are possible within the scope of the technical concept of the present invention.

[0142] Example 1 A varnish was prepared using the following compound 1 as the solid component, N-methyl-2-pyrrolidone and butyl cellosolve as the solvent component, and the following compound 2 as the coloring component, with the solid content being 5 mol % (<10 mol %) relative to the total solid component. The varnish was applied to a substrate and baked at 230°C to obtain a 100 nm film. The obtained film was subjected to a rubbing treatment to obtain comparative alignment film 1. The absorption spectrum of the obtained comparative alignment film 1 was measured in the measurement range of 350 nm to 800 nm using a UV-visible spectrophotometer (U-4100 model, manufactured by Hitachi High-Tech Corporation). Figure 7 shows the absorption spectrum of the alignment film of Example 1. The transmittance of the alignment film of Example 1 at 450 nm was approximately 99%, which was higher than 98%.

[0143] ...Compound 1

[0144] In the chemical formula of Compound 1, X １ is structural formula (X-18), Y １ is structural formula (Y1-21), R １ is -H (hydrogen atom), and n is a positive integer.

[0145] ...Compound 2

[0146] In the chemical formula of Compound 2, X １ is structural formula (X-18), Y ２ is structural formula (Y2-5), R １ is -H (hydrogen atom), and n is a positive integer.

[0147] Comparative Example 1: A varnish was prepared using Compound 1 as the solid component, N-methyl-2-pyrrolidone and butyl cellosolve as the solvent components, and Compound 2 as the coloring component, with the total solid content being 30 mol 1% (>10 mol %). The varnish was applied to a substrate and baked at 230°C to obtain a 100 nm film. The resulting film was subjected to a rubbing treatment to obtain Alignment Film 1. The absorption spectrum of the resulting alignment film was measured in the measurement range of 350 nm to 800 nm using a UV-Visible Spectrophotometer (Hitachi High-Tech Corporation, Model U-4100). Figure 8 shows the absorption spectrum of the alignment film of Comparative Example 1. The transmittance of the alignment film of Comparative Example 1 at 450 nm was approximately 97%, lower than 98%.

[0148] 100: Liquid crystal light control device, 102: Liquid crystal light control element, 104: Control circuit, 106: Light source, 1021: First liquid crystal panel, 1022: Second liquid crystal panel, 1023: Third liquid crystal panel, 1024: Fourth liquid crystal panel, AL11: First alignment film, AL12: Second alignment film, E11, E21, E31, E41: First electrode, E11A, E21A, E31A, E41A: First strip-shaped electrode, E11B, E21B, E31B, E41B: Second strip-shaped electrode, E12, E22, E32, E42: Second electrode, E12A, E22A, E32A, E42A: Third strip-shaped electrode, E12B, E22B, E32B, E42B: Fourth strip-shaped electrode, LC1: First liquid crystal crystal layer, LC2: second liquid crystal layer, LC3: third liquid crystal layer, LC4: fourth liquid crystal layer, F1: first flexible wiring board, F2: second flexible wiring board, F3: third flexible wiring board, F4: fourth flexible wiring board, PE11: first power supply line, PE12: second power supply line, PE13: third power supply line, PE14: fourth power supply line, PE15: fifth power supply line, PE16: sixth power supply line, PT11: first power supply terminal, PT12: second power supply terminal, S11, S21, S31, S41: first substrate, S12, S22, S32, S42: second substrate, T11: first connection terminal, T12: second connection terminal, T13: third connection terminal, T14: fourth connection terminal

Claims

1. A liquid crystal light control device comprising: a pair of substrates; a pair of alignment films between the pair of substrates; and a liquid crystal layer between the pair of alignment films, wherein the pair of substrates are each provided with an electrode, and at least one of the pair of alignment films has a transmittance of 98% or more at a wavelength of 450 nm.

2. The liquid crystal light control device according to claim 1, wherein the varnish forming the alignment film contains a solid component and a solvent component, the solid component contains a coloring material, and the content of the coloring material relative to the total solid component is less than 10 mol %.

3. The liquid crystal light control device according to claim 1, wherein at least one of the pair of alignment films has a thickness of 20 nm or more and 200 nm or less.

4. The liquid crystal light control device according to claim 3, wherein at least one of the pair of alignment films has a thickness of 40 nm or more and 150 nm or less.

5. A liquid crystal light control device as described in claim 2, wherein the solid content is composed of a photodegradable component and a non-photodegradable component, the content of the photodegradable component relative to the total solid content is 20% by mass or more and 50% by mass or less, and the content of the non-photodegradable component relative to the total solid content is 50% by mass or more and 80% by mass or less.

6. A liquid crystal light control device as described in claim 5, wherein the content of the coloring material in the total of the photodecomposition components is less than 10 mol %, and the content of the coloring material in the total of the non-photodecomposition components is less than 10 mol %.

7. The liquid crystal light control device according to claim 2, wherein the coloring material is a polyamic acid or a polyamic acid ester having a unit structure of the following chemical formula (4). In the chemical formula (4), X １ is a tetravalent organic group; Y ２ is a divalent organic group having an atom with an electronegativity of 3 or more; R １ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and n is a positive integer.

8. The liquid crystal light control device according to claim 7, wherein the atoms having an electronegativity of 3 or more are selected from nitrogen (N), oxygen (O), fluorine (F), and chlorine (Cl).

9. The above Y ２ The liquid crystal light control device according to claim 7 , wherein: ...(5) In the chemical formula (5) and the chemical formula (6), A １ A is a single bond, an ester bond, an amide bond, a thioester bond, or a divalent organic group having 2 to 20 carbon atoms; ３ is an atom having an electronegativity of 3 or more, a hydrogen atom, a halogen atom, a hydroxyl group, an amino group, a thiol group, a nitro group, a phosphate group, or a monovalent organic group having 1 to 20 carbon atoms; a is an integer of 1 to 4, and when a is 2 or more, ３ are the same or different, b and c are each independently an integer of 1 to 2, ３ When A is singular, ３ is an atom having an electronegativity of 3 or more; ３ When there are a plurality of atoms, at least one of them is an atom having an electronegativity of 3 or more, and * is the Y ２ and the adjacent nitrogen (N).

10. The above Y ２ is represented by the following structural formulas (Y2-1) to (Y2-42), ２ The liquid crystal light control device according to claim 9 , wherein:

11. The liquid crystal light control device according to claim 5, wherein the photodecomposition component is a polyamic acid or a polyamic acid ester having a unit structure of the following chemical formula (7): In the chemical formula (7), X ２ is represented by the following structural formulas (X2-1) to (X2-4), ３ is a divalent organic group, R １ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and n is a positive integer. In structural formulae (X2-1) to (X2-4), R ３ ~R ２３ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, a monovalent organic group having 1 to 6 carbon atoms containing a fluorine atom, or a phenyl group, and * is ２ and the adjacent carbon (C).

12. In the structural formulas (X2-1) to (X2-4), ３ ~R ２３ The liquid crystal light control device according to claim 11 , wherein is represented by a hydrogen atom, a halogen atom, a methyl group, or an ethyl group.

13. In the structural formulas (X2-1) to (X2-4), ３ ~R ２３ The liquid crystal light control device according to claim 11 , wherein is represented by a hydrogen atom, a methyl group, or an ethyl group.

14. The structural formula (X2-1) is represented by the following structural formulas (X2-11) to (X2-16), and * represents the X ２ The liquid crystal light control device according to claim 11 , wherein the carbon atom (C) is bonded to the adjacent carbon atom (C).

15. The liquid crystal light control device according to claim 11, wherein the structural formula (X2-1) is represented by the following structural formulas (X2-11), (X2-12), and (X2-12a).

16. The liquid crystal light control device according to claim 5, wherein the non-photodecomposition component is a polyamic acid or a polyamic acid ester having a unit structure of the following chemical formula (11). In the chemical formula (11), X ３ is represented by the following structural formulas (X3-1) to (X3-22): ３ is a divalent organic group, R １ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, n is a positive integer, and * in the following structural formulas (X3-1) to (X3-22) represents the bonding position to the adjacent carbon (C).

17. The above X ３ The liquid crystal light control device according to claim 16, represented by the structural formulas (X3-9), (X3-17), (X3-18), (X3-19), and (X3-20).

18. The above X ３ The liquid crystal light control device according to claim 16, represented by the structural formulas (X3-18), (X3-19), and (X3-20).

19. The above Y ３ The liquid crystal light control device according to claim 11 or 16, wherein: ...(8) In the chemical formula (8) and the chemical formula (9), A １ A is a single bond, an ester bond, an amide bond, a thioester bond, or a divalent organic group having 2 to 20 carbon atoms; ３ represents an atom having an electronegativity of 3 or more, a hydrogen atom, a halogen atom, a hydroxyl group, an amino group, a thiol group, a nitro group, a phosphate group, or a monovalent organic group having 1 to 20 carbon atoms; a represents an integer of 1 to 4; b and c each independently represent an integer of 1 to 2; * represents Y ３ and the adjacent nitrogen (N).

20. The above Y ３ The liquid crystal light control device according to claim 11 or 16, wherein the compound is represented by the following structural formulas (Y3-1) to (Y3-38) and the following structural formulas (Y32-1) to (Y32-42).

21. The liquid crystal light control device according to claim 2, wherein the solid content of the varnish as a whole is 0.5% by mass or more and 15% by mass or less.

22. The liquid crystal light control device according to claim 21, wherein the content of the solid matter in the entire varnish is 2% by mass or more and 10% by mass or less.

23. The liquid crystal light control device described in claim 2, wherein the solvent component of the varnish includes a good solvent and a solvent having a surface tension lower than that of the good solvent, and the content of the solvent having a low surface tension relative to the entire varnish is 10% by weight or more and 40% by weight or less.

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