Substrate for optical device

Abstract

The invention relates to a substrate for an optical device. The present application can provide a substrate for an optical device that appropriately maintains a cell gap between an upper substrate and a lower substrate of a liquid crystal cell, has excellent attachment force between the upper substrate and the lower substrate, and has excellent visibility by improving a flash phenomenon and a rainbow phenomenon.

Description

Technical Field

[0001] This application relates to substrates for optical devices.

[0002] This application claims priority to Korean Patent Application No. 10-2023-0120917, dated September 12, 2023, the disclosure of which is incorporated herein by reference in its entirety. Background Technology

[0003] For the long-term stability and large-area scalability of liquid crystal cells using flexible substrates, it is important to maintain cell gaps between the upper and lower substrates and to impart adhesive force between them. To maintain cell gaps between the upper and lower substrates, spacers can be used, and the spacers can have a column shape or a partition wall shape (Non-Patent Literature 1: "Bonding of Two Plastic Substrates for Flexible LCDs", SID Symposium Digest, 38, pp. 653-656 (2007)). Summary of the Invention

[0004] Technical issues

[0005] The problem of this application is to provide a substrate for an optical device that appropriately maintains the cell gap between the upper and lower substrates of a liquid crystal cell, has excellent adhesion between the upper and lower substrates, and has excellent visibility by improving the flicker and rainbow phenomena.

[0006] Technical solution

[0007] This application relates to a substrate. The substrate is a substrate for optical devices and can be used as a substrate for manufacturing optical devices.

[0008] Figures 1 to 3 An exemplary substrate for an optical device is shown. The substrate may include a substrate layer 101, spacers 103, and an alignment film 104. The substrate may include spacers on the substrate layer and may include an alignment film on the spacers. That is, the spacers may be present between the substrate layer and the alignment film.

[0009] As a substrate layer, inorganic films, such as glass films, crystalline or amorphous silicon films, or quartz or ITO (indium tin oxide) films, can be used; or polymer films; etc., and polymer films can be used for realizing flexible elements.

[0010] In one example, the substrate layer can be a polymer film. As a polymer film, TAC (triacetyl cellulose); COP (cyclic olefin copolymer), such as norbornene derivatives; PMMA (poly(methyl methacrylate)); PC (polycarbonate); PE (polyethylene); PP (polypropylene); PVA (polyvinyl alcohol); DAC (diacetyl cellulose); PA (polyacrylate); PES (polyethersulfone); PEEK (polyether ether ketone); PPS (polyphenyl sulfone); PEI (polyetherimide); PEN (polyethylene naphthalate); PET (polyethylene terephthalate); PI (polyimide); PSF (polysulfone); PA (polyarylate); or amorphous fluoropolymers; etc., but not limited to these. A coating of gold, silver, or silicon compounds (e.g., silica or silicon monoxide), or a functional layer such as an antireflective layer, may also be present in the substrate layer as needed.

[0011] The thickness of the substrate layer can range from 10 μm to 1,000 μm. Specifically, the thickness of the substrate layer can be 20 μm or more, 40 μm or more, 60 μm or more, 80 μm or more, or 100 μm or more, and can be 900 μm or less, 800 μm or less, 700 μm or less, 600 μm or less, 500 μm or less, or 400 μm or less.

[0012] In one example, the substrate layer can be an optically anisotropic film. Films with such optical anisotropy are typically also anisotropic in mechanical properties, and by utilizing such anisotropy, liquid crystal cells or optical devices with excellent durability can be provided. When the optically anisotropic film is applied simultaneously to the first substrate layer and the second substrate layer as described below, it can be included in the liquid crystal cell or optical device such that the slow axis of the first substrate layer is parallel or perpendicular to the slow axis of the second substrate layer. In this specification, the fact that the A-axis is perpendicular to the B-axis can mean that the angle formed by the A-axis and the B-axis is in the range of about 80 degrees to 100 degrees, about 85 degrees to 95 degrees, about 87 degrees to 93 degrees, or about 89 degrees to 91 degrees, or about 90 degrees. In this specification, the fact that the A-axis is parallel to the B-axis can mean that the angle formed by the A-axis and the B-axis is in the range of about 0 degrees to 10 degrees, about 0 degrees to 5 degrees, about 0 degrees to 3 degrees, or about 0 degrees to 1 degree, or about 0 degrees.

[0013] In one example, the substrate layer can each be a polymer film having an in-plane phase difference of 4,000 nm or greater for light with a wavelength of 550 nm. The in-plane phase difference can specifically be 5,000 nm or greater, 6,000 nm or greater, 7,000 nm or greater, 8,000 nm or greater, or 9,000 nm or greater, and can be 50,000 nm or less, 40,000 nm or less, 30,000 nm or less, 20,000 nm or less, 18,000 nm or less, 16,000 nm or less, 15,000 nm or less, or 12,000 nm or less. This can advantageously provide a liquid crystal cell or optical device free from optical defects such as rainbow effects.

[0014] In this specification, the in-plane phase difference can be defined by the following Equation 1.

[0015] [Equation 1]

[0016] Rin=(nx-ny)×d

[0017] In Equation 1, Rin is the in-plane phase difference, nx is the refractive index of the polymer film along the slow axis, ny is the refractive index of the polymer film along the fast axis, and d is the thickness of the polymer film (nm). The slow axis and fast axis can be perpendicular to each other within the plane of the polymer film. nx and ny can each be the refractive index for light with a wavelength of 550 nm. In this specification, the slow axis can refer to the axis along the direction of highest refractive index within the plane of the polymer film. In this specification, the fast axis can refer to the axis along the direction of lowest refractive index within the plane of the polymer film.

[0018] The substrate layer can be an anisotropic polymer film that acquires optical anisotropy through stretching. Examples of polymer films include: polyolefin films, such as polyethylene or polypropylene films; cyclic olefin polymer (COP) films, such as polynorbornene films; polyvinyl chloride films; polyacrylonitrile films; polysulfone films; polyacrylate films; PVA (polyvinyl alcohol) films; or cellulose ester-based polymer films, such as TAC (triacetyl cellulose) films; polyester films; or polycarbonate films; or copolymer films of two or more monomers forming the polymer; and so on. In one example, polyester films, such as PET (polyethylene terephthalate) films, can be used as the film. That is, films exhibiting in-plane phase differences within the above range are known in industry, and in the case of polymer films, such films exhibit asymmetry in mechanical properties, in addition to large optical anisotropy, due to stretching during the manufacturing process. A representative example of such delayed films known in industry is a stretched polyester film, such as a stretched PET (polyethylene terephthalate) film.

[0019] The spacer can be a spacer in the shape of a partition wall (hereinafter referred to as a partition wall spacer). The partition wall spacer can confine the liquid crystal compound by positioning it within the internal region of the partition wall. This can improve the adhesion between the upper and lower substrates while maintaining the cell gap between them, and is also advantageous in terms of the physical rigidity of the liquid crystal cell.

[0020] When the substrate with spacers is viewed from the normal direction, the spacers can be straight lines or curves. When the spacers are viewed from the normal direction, the closed shapes separated by the spacers can be circular, elliptical, polygonal, or irregular. The closed shapes separated by the spacers are regions without spacers, and therefore can also be referred to as spacerless regions. Irregular shapes can refer to unstructured shapes other than circular, elliptical, and polygonal shapes. In this specification, the normal direction can refer to a direction parallel to the thickness direction of the liquid crystal cell or optical device, or the stacking direction of the layers included in the liquid crystal cell or optical device.

[0021] The partition walls can be regularly patterned or randomly patterned. In the case of regularly patterned partition walls, when viewed from the normal direction onto the substrate on which the partition walls are formed, the closed shapes separated by the partition walls can have a specific shape. A specific shape can mean that all closed shapes are n-sided polygons with the same value n (n is an integer of 3 or greater, and the upper limit is, for example, 10 or less), and all closed shapes are also nearly identical in size. Regularly patterned partition walls can include honeycomb partition walls or quadrilateral partition walls. Honeycomb partition walls can have partition-free regions formed by combinations of regular hexagons, and quadrilateral partition walls can have partition-free regions formed by combinations of regular squares or rhombuses. In the case of randomly patterned partition walls, when viewed from the normal direction, the closed shapes separated by the partition walls can have an irregular shape. In one instance, a randomly patterned partition wall can be derived from a randomization of a regularly patterned partition wall. The randomization of regular patterned partition wall spacers can refer to the random movement of vertices and / or line segments that form the closed polygonal shape of the regular patterned partition wall spacer. Through randomization, line segments can be transformed into curves. During randomization, multiple vertices do not overlap with each other, and multiple line segments do not interrupt or intersect each other. Randomized partition wall spacers derived from regular patterned partition wall spacers can maintain the relationship between the vertices and line segments of the regular pattern. In one instance, where a honeycomb-shaped regular patterned partition wall spacer is randomized, three curves can meet at an intersection point like a honeycomb shape.

[0022] In one example, the spacer wall can be a regularly patterned spacer wall. With regularly patterned spacer wall, it is more advantageous to adjust the orientation direction of the liquid crystal in the alignment film on the side of the spacer so as not to affect the polarization direction of the polarizer. The fact that the orientation direction of the liquid crystal does not affect the polarization direction of the polarizer can mean that the angle formed by the orientation direction of the liquid crystal and the polarization direction of the polarizer (the transmission axis of the polarizer) is close to 0 degrees or 90 degrees, for example, in the range of 0 to 10 degrees, or in the range of 80 to 90 degrees. This can help solve the light leakage problem caused by the liquid crystal orientation on the side of the spacer. However, there are also cases where it is difficult to adjust to the above angle even in regularly patterned spacer wall (e.g., in the case of a diamond pattern). When using the substrate for the optical device of this application, the problem caused by the liquid crystal orientation on the side of the spacer can be solved.

[0023] In one example, the spacer wall can be a randomly patterned spacer wall. Compared to regularly patterned spacer wall, randomly patterned spacer wall has the advantage that no cross-shaped diffraction pattern is observed when viewed from a point source such as sunlight. However, in the case of randomly patterned spacer wall, it may not be easy to adjust the orientation direction of the liquid crystal in the alignment film on the side of the spacer to form the angle with the polarization direction of the polarizer. Therefore, in the case of randomly patterned spacer wall, the liquid crystal region in the alignment film on the side of the spacer affects the polarization direction, thereby potentially increasing the likelihood of light leakage. In particular, strong light leakage may occur at an angle of approximately 45 degrees between the orientation direction of the liquid crystal and the polarization direction. This may cause flashes and may also result in circular rainbow patterns due to successive flashes at similar angles. When using the substrate for optical devices of this application, the problem caused by the liquid crystal orientation on the side of the spacer can be solved.

[0024] The spacer may contain a curable resin. The curable resin may be a thermosetting resin or a photocurable resin. Thermosetting resins may include one or more selected from silicone resins, silicone resins, furan resins, polyurethane resins, epoxy resins, amino resins, phenolic resins, urea resins, polyester resins, and melamine resins. Photocurable resins may be UV-curable resins. In one example, the photocurable resin may be an acrylic resin. Acrylic resins may refer to acrylic polymers containing polymeric units derived from (meth)acrylate monomers. Acrylic polymers may include one or more selected from alkyl acrylate polymers, polyester acrylate polymers, polystyrene acrylate polymers, epoxy acrylate polymers, polyurethane acrylate polymers, polybutadiene acrylate polymers, and silicone acrylate polymers. The spacer may contain a cured product of the curable resin composition. The curable resin composition may be a thermosetting resin composition or a photocurable resin composition. The thermosetting resin composition or the photocurable resin composition may contain monomers and / or polymers to enable the inclusion of the aforementioned curable resin by curing.

[0025] In one example, the spacer may also contain a black dye. If the spacer also contains a black dye, it can help reduce light leakage occurring in the spacer area. As the black dye, inorganic substances such as carbon black or organic substances such as lactam black can also be used. The amount of black dye can be suitably selected without prejudice to the purpose of this application. In one example, the black dye may be included in the range of 0.1 parts by weight to 20 parts by weight relative to 100 parts by weight of the solid contents of the curable resin composition.

[0026] In one example, the spacers can be formed using a patterning process. For instance, the spacers can be formed using a photolithography process. The photolithography process can include applying a curable resin composition to a substrate layer (or, when an electrode layer is formed on the substrate layer), and then irradiating it with ultraviolet light via a pattern mask. The pattern mask can be patterned into ultraviolet-transmitting regions and ultraviolet-blocking regions. The photolithography process can also include washing the ultraviolet-irradiated curable resin composition. The ultraviolet-irradiated regions cure, while the unirradiated regions remain in a liquid phase, allowing them to be removed by the washing process, thereby patterning them into spacer shapes. Therefore, the ultraviolet-transmitting regions of the pattern mask can correspond to the spacer shapes, and the ultraviolet-blocking regions of the pattern mask can correspond to the shapes of the internal regions formed by the spacers. In the photolithography process, to facilitate separation of the curable resin composition from the pattern mask after ultraviolet irradiation, the pattern mask can be released, or release paper can be placed between the layer of the curable resin composition and the pattern mask.

[0027] In one example, the spacers can be formed by an imprinting process. The imprinting process can be performed by applying a curable resin composition to a substrate layer (or, when an electrode layer is formed on the substrate layer), and then removing the imprinting die after contacting the curable resin composition. The imprinting die can have a pattern capable of transferring the desired spacer pattern. As the imprinting die, any imprinting die known in the industry can be used without limitation; for example, a flexible die can be used. As the material for the flexible die, any material known in the industry can be applied, for example, a flexible adhesive resin or PDMS (polydimethylsiloxane), but not limited to these. In the imprinting process, a curing process for curing the curable resin composition can also be performed. The curing process can be performed by applying appropriate energy for curing the curable resin composition, such as irradiation with heat and / or light. The energy used for curing can be, for example, ultraviolet light. There are no particular limitations on the conditions under which the energy used for curing is applied, as long as it is performed in a manner that allows the curable resin composition to cure appropriately. Irradiation with the energy used for curing can be performed, for example, before, simultaneously with, or after contacting the imprinting die with the curable resin composition. In addition, in the embossing method, the embossing mold can be released to easily separate the curable resin composition from the embossing mold.

[0028] The linewidth, pitch, thickness, and area of ​​the spacers can be suitably selected without prejudice to the purpose of this application. For example, the linewidth of the spacers can be in the range of 10 μm to 500 μm or in the range of 10 μm to 50 μm. When the spacers are viewed from the normal direction, the linewidth of the spacers refers to the linewidth of the spacers and specifically to the linewidth of the upper surface of the spacers. The spacing of the spacers can be in the range of 100 μm to 1000 μm or in the range of 200 μm to 500 μm. When the spacers are viewed from the normal direction, the spacing of the spacers can refer to the maximum distance between any two points in the cross-sectional shape of the region without spacers. The area ratio of the spacers relative to 100% of the total area of ​​the substrate layer can be, for example, about 5% or more and 50% or less. When the substrate on which the spacers are formed is viewed from the normal direction, the area ratio of the spacers can refer to the ratio of the total area of ​​the spacers to the total area of ​​the substrate layer. When the area of ​​the spacer is within the above range, it is beneficial to ensure excellent electro-optic properties while ensuring sufficient adhesion between the upper and lower substrates. The thickness of the spacer (the height of the partition wall) can be, for example, in the range of 1 μm to 30 μm or 3 μm to 20 μm.

[0029] The surface of the alignment film 104 may include an upper surface a1, a lower surface a3, and an inclined side surface (hereinafter referred to as the inclined surface) a2 between the upper surface a1 and the lower surface a3. The surface of the alignment film may refer to the surface opposite to the surface facing the spacer. The upper surface of the alignment film may be caused by the spacer. Therefore, based on the substrate layer, the height of the upper surface may be greater than the height of the lower surface. The height difference between the upper and lower surfaces of the alignment film is caused by the height of the spacer. The upper surface of the alignment film may be formed to correspond to the partition wall (protrusion of the spacer) of the spacer.

[0030] When the alignment film has a tilted surface, light leakage can be suppressed even when the liquid crystal cell is used with a polarizer, thus improving the problems of flash and rainbow phenomena. In particular, when the liquid crystal cell is placed between two polarizers whose absorption axes intersect, there is a possibility of strong light leakage, but this problem can be improved by using the optical device substrate of this application.

[0031] When manufacturing the lower substrate of a liquid crystal cell, an alignment film can be formed on the spacers after the spacers are formed. Therefore, the alignment film can exist on both the upper and side surfaces of the spacers. The tilted surface of the alignment film can be caused by the slope of the side surface of the spacer. Liquid crystals positioned close to the alignment film formed on the side surface of the spacer can be vertically aligned along the side surface of the alignment film. If the slope angle of the side surface of the alignment film is too large, for example, if it is 90 degrees, the optical axis of the liquid crystal aligned along the side surface of the alignment film may be horizontal relative to the substrate layer. In this case, the liquid crystal generates a phase difference, making it possible for light leakage to occur due to misalignment with the polarization direction if it is used with a polarizer. When the tilt angle of the tilted surface of the alignment film is set to a predetermined range or smaller, the optical axis of the liquid crystal aligned along the side surface of the alignment film may not be horizontal relative to the substrate layer, but may be tilted. In this case, the phase difference of the liquid crystal can be reduced, so that when it is used with a polarizer, light leakage due to misalignment with the polarization direction can be suppressed.

[0032] The tilt angle θa formed by the upper surface a1 and the tilted surface a2 of the alignment membrane (hereinafter referred to as the tilt angle of the alignment membrane) can be appropriately selected in terms of problem-solving. The tilt angle θa of the alignment membrane can be, for example, 47 degrees or less. Specifically, the tilt angle of the alignment membrane can be 46 degrees or less or 45 degrees or less. The tilt angle of the alignment membrane can be more specifically 40 degrees or less, 35 degrees or less, 30 degrees or less, 25 degrees or less, 20 degrees or less, 15 degrees or less, 10 degrees or less, 8 degrees or less, or 6 degrees or less. The lower limit of the tilt angle of the alignment membrane can be, for example, 1 degree or more, 2 degrees or more, 3 degrees or more, 4 degrees or more, 5 degrees or more, or 6 degrees or more.

[0033] The alignment film can be a vertical alignment film or a horizontal alignment film. In this specification, "horizontal alignment film" can mean a layer containing an alignment material that imparts a horizontal alignment force to liquid crystal compounds present in adjacent liquid crystal regions. In this specification, "vertical alignment film" can mean a layer containing an alignment material that imparts a vertical alignment force to liquid crystal compounds present in adjacent liquid crystal regions. The pretilt angle of adjacent liquid crystal compounds relative to the vertical alignment film can be in the range of 80 to 90 degrees, 85 to 90 degrees, or about 87 to 90 degrees, and the pretilt angle of adjacent liquid crystal compounds relative to the horizontal alignment film can be in the range of 0 to 10 degrees, 0 to 5 degrees, or 0 to 3 degrees. Unlike pressure-sensitive adhesive layers, the alignment film may not have adhesive force for bonding the upper and lower substrates. In one example, in Figures 4 to 6 In the state of the liquid crystal cell, the alignment film can have a peel force close to zero relative to the upper substrate.

[0034] The alignment film can be a rubbing alignment film or a photoalignment film. The orientation direction of the alignment film can follow the rubbing direction in the case of a rubbing alignment film, and the orientation direction of the polarized light to be irradiated in the case of a photoalignment film. This orientation direction can be determined using a detection method employing an absorption-type linear polarizer. Specifically, the orientation direction can be determined as follows: with the liquid crystal compound contained in the liquid crystal region horizontally aligned, an absorption-type linear polarizer is placed on one side of the liquid crystal region, and the transmittance is measured while rotating the polarizer 360 degrees. When the liquid crystal region or one side of the absorption-type linear polarizer is irradiated with light in the above state, and the brightness (transmittance) is measured from the other side simultaneously, if the absorption axis or transmission axis coincides with the orientation direction of the liquid crystal alignment film, the transmittance tends to be low. The orientation direction can be determined by simulation reflecting the refractive index anisotropy, etc., of the applied liquid crystal compound. Methods for determining the orientation direction based on the pattern of the liquid crystal region are known, and in this application, the orientation direction of the alignment film can be determined using such known methods.

[0035] The alignment film may contain one or more of the following: materials known to exhibit orientation ability through rubbing, such as polyimide compounds, poly(vinyl alcohol) compounds, poly(amic acid) compounds, polystyrene compounds, polyamide compounds, and polyoxyethylene compounds; or materials known to exhibit orientation ability through light irradiation, such as polyimide compounds, polyamic acid compounds, polynorbornene compounds, phenylmaleimide copolymer compounds, polyvinyl cinnamate compounds, polyazobenzene compounds, polyvinylimide compounds, polyvinyl alcohol compounds, polyamide compounds, polyethylene compounds, polystyrene compounds, polyphenylene phthalamide compounds, polyester compounds, CMPI (chloromethylated polyimide) compounds, PVCI (polyvinylcinnamate) compounds, and polymethyl methacrylate compounds, but not limited thereto.

[0036] The surface of the spacer may include an upper surface b1 and a side surface b2 connected to the upper surface b1. The surface of the spacer may refer to the surface opposite to the surface of the spacer facing the substrate layer. Figures 1 to 3 An illustrative example is shown where there is no lower region between the protrusions (spacer walls) of the spacer. However, depending on the spacer's manufacturing process, for example, when the spacer is formed by an imprinting process, the lower region between the protrusions of the spacer can also be formed by a residual film. When the spacer is formed by a photolithography process, a spacer without a residual film can be formed. Alternatively, if a residual film is required, it can also be formed by a photolithography process. The lower region provides the lower surface of the spacer, wherein the surface of the spacer may include an upper surface, a lower surface, and a side surface between the upper and lower surfaces. The angle θb formed by the upper surface b1 and the side surface b2 of the spacer (hereinafter referred to as the tilt angle of the spacer) can be in the range of 30 degrees to 90 degrees. The tilt angle θb of the spacer can be, for example, 30 degrees or greater, 35 degrees or greater, 40 degrees or greater, 45 degrees or greater, 50 degrees or greater, 55 degrees or greater, 60 degrees or greater, 65 degrees or greater, 70 degrees or greater, 75 degrees or greater, 80 degrees or greater, or 85 degrees or greater, and can be 90 degrees or less, 85 degrees or less, 80 degrees or less, 75 degrees or less, 70 degrees or less, 65 degrees or less, 60 degrees or less, or 55 degrees or less.

[0037] There are no particular limitations on the method for adjusting the tilt angle of the spacers, and methods known in the relevant art can be appropriately applied. In one example, when the spacers are formed by a photolithography process, the UV light irradiated during curing can be controlled. If the UV light is direct light, the tilt angle of the spacers can also be formed to be high, such as 80 degrees or greater, 85 degrees or greater, or close to 90 degrees. If the UV light is diffused light, the tilt angle of the spacers can be adjusted to be lower. If the UV light is diffused light, the light also diffuses to the side surface, where the tail may increase as the light intensity increases, making the tilt angle potentially smaller. Generally, UV light irradiated from a UV lamp is diffused light, and it can also be made direct light if a light guide plate is applied to the side of the UV lamp that is irradiated so that the light can propagate in a straight line. In another example, when the spacers are formed by an imprinting process, an imprinting mold with an engraved pattern corresponding to the spacers having the desired tilt angle can be used.

[0038] The substrate for the optical device may further include a base coating 105 present between the spacer 103 and the alignment film 104. The surface of the base coating may include an upper surface c1, a lower surface c3, and an inclined side surface (hereinafter referred to as the inclined surface) c2 between the upper surface c1 and the lower surface c3. The surface of the base coating may refer to the surface opposite to the spacer-facing surface of the base coating. The angle θc formed by the upper surface c1 and the inclined surface c2 of the base coating (hereinafter referred to as the tilt angle of the base coating) may be appropriately selected within a range that satisfies the tilt angle of the alignment film. The tilt angle θc of the base coating may, for example, be in the range of 5 degrees to 60 degrees. Specifically, the tilt angle of the base coating may be 5 degrees or greater, or 10 degrees or greater, and may be 60 degrees or less, 55 degrees or less, 50 degrees or less, 45 degrees or less, 40 degrees or less, 35 degrees or less, 30 degrees or less, or 25 degrees or less. The tilt angle of the primer can be adjusted, for example, by controlling the thickness of the primer applied to the spacer. In one instance, if the primer is applied thickly to the spacer, the tail of the tilted surface c2 in the primer may increase, which may reduce the tilt angle of the primer.

[0039] The base coating may comprise a curable resin. The curable resin may be a thermosetting resin or a photocurable resin. Thermosetting resins may include one or more of the following: silicone resins, silicone resins, furan resins, polyurethane resins, epoxy resins, amino resins, phenolic resins, urea resins, polyester resins, and melamine resins. Photocurable resins may be UV-curable resins. In one example, the photocurable resin may be an acrylic resin. Acrylic resins may refer to acrylic polymers comprising polymeric units derived from (meth)acrylate monomers. Acrylic polymers may include one or more of the following: alkyl acrylate polymers, polyester acrylate polymers, polystyrene acrylate polymers, epoxy acrylate polymers, polyurethane acrylate polymers, polybutadiene acrylate polymers, and silicone acrylate polymers.

[0040] The base coating may contain a cured product of a curable resin composition. The curable resin composition may be a thermosetting resin composition or a photocurable resin composition. The thermosetting or photocurable resin composition may contain monomers and / or polymers to enable the inclusion of the aforementioned curable resin by curing. In one example, the curable resin composition may contain a (meth)acrylate compound. The (meth)acrylate compound may be a polyfunctional (meth)acrylate compound having two or more (meth)acryloyl groups at the ends. The (meth)acrylate compound may have 2 to 6 or 2 to 4 (meth)acryloyl groups. In one example, the curable resin composition may contain a difunctional (meth)acrylate compound, a trifunctional (meth)acrylate compound, and a tetrafunctional (meth)acrylate compound. In one example, the curable resin composition may also contain a thiol compound. The thiol compound may be a polyfunctional thiol compound having two or more thiol groups (-SH) at the ends. The thiol compound may have 2 to 6, 2 to 4, or 4 thiol groups (-SH).

[0041] In one example, the base coat may also contain a black dye. A base coat containing a black dye can be formed by adding a black dye to the curable resin composition. When the base coat also contains a black dye, it can help reduce light leakage in areas of the base coat present on the side surfaces of the spacers. Inorganic substances such as carbon black or organic substances such as lactam black can also be used as the black dye. The amount of black dye can be suitably selected without prejudice to the purpose of this application. The black dye may be contained in the range of 10 to 50 parts by weight relative to 100 parts by weight of the solid contents of the curable resin composition.

[0042] The substrate for the optical device may also include an electrode layer 102 between the substrate layer 101 and the spacer 103. The description of the first electrode layer and / or the second electrode layer described below can also be applied to the electrode layer.

[0043] The method for adjusting the tilt angle of the alignment membrane may be appropriately selected without prejudice to the purpose of this application. Figures 1 to 3 The structure of a substrate in which the angle of the alignment membrane is controlled by various methods is illustrated by way of example.

[0044] In one instance, such as Figure 1 As shown, the tilt angle θa of the alignment film 104 can be controlled by adjusting the coating thickness 104 of the alignment film. If the alignment film is coated thickly, the tail of the alignment film on the tilted surface a2 of the alignment film may increase, which may reduce the tilt angle of the alignment film.

[0045] In another instance, such as Figure 2 As shown, the tilt angle θa of the alignment film 104 can be controlled by applying a base coat 105 beneath the alignment film 104. Applying the base coat creates a slope on the side surface b2 of the spacer 103. If the base coat is applied thickly, the tail of the base coat c2 on the side surface b2 of the spacer increases, potentially reducing the tilt angle of the base coat. Consequently, the tilt angle of the alignment film may also decrease.

[0046] In another instance, such as Figure 3 As shown, the tilt angle θa of the alignment membrane 104 can be controlled by forming the side surface b2 of the spacer 103 with a slope when forming the spacer 103. The smaller the tilt angle of the spacer (θb, the angle formed by the upper surface and the side surface of the spacer), the smaller the tilt angle θa of the alignment membrane may be.

[0047] When providing the substrate for the optical device of this application, any one of the three methods for controlling the tilt angle of the alignment film may be applied, or two methods may be applied, or all three methods may be applied.

[0048] This application also relates to optical devices including the substrate. The optical device may include a liquid crystal cell. Figures 4 to 6 An exemplary liquid crystal cell including the substrate for an optical device of this application is shown. Figure 4 Exemplary examples include Figure 1 The liquid crystal cell is used as a substrate for optical devices. Figure 5 Exemplary examples include Figure 2 The liquid crystal cell is used as a substrate for optical devices. Figure 6 Exemplary examples include Figure 3 The liquid crystal cell is used as a substrate for optical devices.

[0049] A liquid crystal cell may include an upper substrate, a lower substrate, and a liquid crystal layer containing a liquid crystal compound between the upper substrate and the lower substrate.

[0050] The upper substrate may include a first substrate layer 301 and a pressure-sensitive adhesive layer 303. An optical device substrate may be used as the lower substrate. The lower substrate may include a second substrate layer 101, spacers 103, and an alignment film 104. A liquid crystal layer 200 may be present in the region between the upper and lower substrates. The surface of the alignment film may include an upper surface, a lower surface, and an inclined surface between the upper and lower surfaces. The tilt angle formed by the upper surface of the alignment film and the inclined surface satisfies a predetermined range, thereby improving flash and rainbow phenomena.

[0051] The descriptions in the substrate for optical devices can be applied equivalently to the descriptions in the lower substrate. Therefore, the descriptions of the substrate layer, electrode layer, spacers, undercoat layer, and alignment film in the substrate for optical devices can be applied equivalently to the descriptions of the second substrate layer, second electrode layer, spacers, undercoat layer, and alignment film in the lower substrate. The descriptions in the substrate layer of the substrate for optical devices can be applied equivalently to the first substrate layer of the upper substrate.

[0052] A pressure-sensitive adhesive layer may be present on the inner surface of the first substrate layer. In this specification, the "inner surface" of the configuration included in the liquid crystal cell may refer to the surface facing the liquid crystal region (liquid crystal layer). In this specification, the "outer surface" of the configuration included in the liquid crystal cell may refer to the surface opposite to the surface facing the liquid crystal region (liquid crystal layer). By using such a pressure-sensitive adhesive layer, adhesion can be imparted between the upper and lower substrates, preventing separation of the liquid crystal cell during or after the bonding process for supporting the liquid crystal composition between the upper and lower substrates. Furthermore, the pressure-sensitive adhesive layer facilitates roll-to-roll processing and prevents the flow of the liquid crystal composition.

[0053] In this specification, the term "pressure-sensitive adhesive composition layer" may refer to a layer formed by applying a pressure-sensitive adhesive composition or curing a pressure-sensitive adhesive composition. The term "curing a pressure-sensitive adhesive composition" may refer to the realization of a cross-linked structure in the pressure-sensitive adhesive composition through physical or chemical action or reaction of the components contained in the pressure-sensitive adhesive composition. Curing may be initiated by, for example, holding at room temperature, applying moisture, applying heat, irradiating with active energy rays, or two or more of the foregoing methods, and in each case, the type of pressure-sensitive adhesive composition for which curing is initiated may be referred to as, for example, a room temperature curing pressure-sensitive adhesive composition, a moisture-curing pressure-sensitive adhesive composition, a thermosetting pressure-sensitive adhesive composition, an active energy ray curing pressure-sensitive adhesive composition, or a mixed-curing pressure-sensitive adhesive composition.

[0054] The pressure-sensitive adhesive layer can be optically transparent. The average transmittance of the pressure-sensitive adhesive layer to light in the visible light region (e.g., wavelengths from 380 nm to 780 nm) can be about 80% or more, 85% or more, 90% or more, or 95% or more.

[0055] The pressure-sensitive adhesive layer can be a liquid crystal aligned pressure-sensitive adhesive layer. The pressure-sensitive adhesive layer can be, for example, a vertically aligned pressure-sensitive adhesive layer or a horizontally aligned pressure-sensitive adhesive layer. In this specification, "vertically aligned pressure-sensitive adhesive" can mean a pressure-sensitive adhesive having an adhesion force capable of bonding an upper substrate and a lower substrate while simultaneously imparting a vertical alignment force to adjacent liquid crystal compounds. In this specification, "horizontally aligned pressure-sensitive adhesive" can mean a pressure-sensitive adhesive having an adhesion force capable of bonding an upper substrate and a lower substrate while simultaneously imparting a horizontal alignment force to adjacent liquid crystal compounds. The pretilt angle of adjacent liquid crystal compounds relative to the vertically aligned pressure-sensitive adhesive can be in the range of 80 degrees to 90 degrees, 85 degrees to 90 degrees, or about 87 degrees to 90 degrees, and the pretilt angle of adjacent liquid crystal compounds relative to the horizontally aligned pressure-sensitive adhesive can be in the range of 0 degrees to 10 degrees, 0 degrees to 5 degrees, or 0 degrees to 3 degrees. According to one example of this application, the pressure-sensitive adhesive layer can be a vertically aligned pressure-sensitive adhesive layer.

[0056] In this specification, the pretilt angle can refer to the angle formed by the director of the liquid crystal compound relative to a plane horizontal to the liquid crystal alignment pressure-sensitive adhesive or alignment film when no voltage is applied. In this specification, the director of the liquid crystal compound can refer to the optical axis or slow axis of the liquid crystal region. Alternatively, when the liquid crystal compound has a rod shape, the director of the liquid crystal compound can refer to the long axis direction, and when the liquid crystal compound has a disk shape, the director of the liquid crystal compound can refer to an axis parallel to the normal direction of the disk plane.

[0057] When the pressure-sensitive adhesive layer is vertically oriented, the surface energy of the pressure-sensitive adhesive can be 16 mN / m or less. The lower limit of the surface energy of the vertically oriented pressure-sensitive adhesive layer can be, for example, 5 mN / m or greater. When the pressure-sensitive adhesive layer is horizontally oriented, the surface energy can be greater than 16 mN / m. The upper limit of the surface energy of the horizontally oriented pressure-sensitive adhesive layer can be, for example, 50 mN / m or less. Surface energy can be measured using a droplet shape analyzer (KRUSS DSA100 product). Specifically, the process of repeatedly dropping deionized water with a known surface tension onto the surface of the pressure-sensitive adhesive to obtain contact angles is repeated five times, thereby obtaining the average of the five resulting contact angle values. Similarly, the process of repeatedly dropping diiodomethane with a known surface tension onto it to obtain contact angles is repeated five times, thereby obtaining the average of the five resulting contact angle values. The surface energy can then be obtained using the average of the obtained contact angles of deionized water and diiodomethane by substituting the surface tension value of the solvent (Strom value) using the Owens-Wendt-Rabel-Kaelble method. The surface energy (γ surface) of a sample can be calculated by considering the dispersion forces between nonpolar molecules and the interaction forces between polar molecules (γ surface = γ dispersion + γ polarity), where the ratio of the polar term (γ polarity) in the surface energy γ surface can be defined as the polarity of the surface.

[0058] The thickness of the pressure-sensitive adhesive layer can be, for example, in the range of 3 μm to 15 μm. When the thickness of the pressure-sensitive adhesive layer is within this range, it is beneficial to minimize defects such as squeezing or crowding of the pressure-sensitive adhesive when used to manufacture liquid crystal cells, while ensuring the adhesion between the upper and lower substrates.

[0059] As a pressure-sensitive adhesive layer, various types of pressure-sensitive adhesives known in the industry as so-called OCA (optically clear adhesive) can be appropriately used. Pressure-sensitive adhesives can differ from OCR (optically clear resin) type adhesives, which cure before the objects to be attached are bonded, because they cure before the objects to be attached are bonded.

[0060] The pressure-sensitive adhesive layer may contain a silicone pressure-sensitive adhesive. In the case of a silicone pressure-sensitive adhesive, the pressure-sensitive adhesive composition may contain a curable silicone compound as the pressure-sensitive adhesive resin. A pressure-sensitive adhesive composition containing a curable silicone compound as the pressure-sensitive adhesive resin may be referred to as a silicone composition. The silicone pressure-sensitive adhesive may contain a cured product of the curable silicone compound as the pressure-sensitive adhesive resin. When using a silicone pressure-sensitive adhesive, it is suitable for exhibiting a perpendicular orientation force relative to the liquid crystal due to the difference in surface energy with the liquid crystal, and it can also be advantageous in preventing liquid crystal contamination. There are no particular limitations on the type of curable silicone compound; for example, a thermosetting silicone compound or a UV-curable silicone compound may be used.

[0061] In one instance, the curable organosilicon compound can be an addition-curable organosilicon compound.

[0062] Specifically, addition-curing organosilicon compounds can be exemplified as (1) organopolysiloxanes containing two or more alkenyl groups in their molecules and (2) organopolysiloxanes containing two or more hydrogen atoms bonded to silicon in their molecules, but are not limited thereto. Such organosilicon compounds can, for example, form cured products through an addition reaction in the presence of a catalyst as described below.

[0063] More specific examples of (1) organopolysiloxanes that may be used in this application may include: dimethylsiloxane-methylvinylsiloxane copolymers with trimethylsiloxane groups at both ends of the molecular chain; methylvinylpolysiloxanes with trimethylsiloxane groups at both ends of the molecular chain; dimethylsiloxane-methylvinylsiloxane-methylphenylsiloxane copolymers with trimethylsiloxane groups at both ends of the molecular chain; dimethylpolysiloxanes with dimethylvinylsiloxane groups at both ends of the molecular chain; methylvinylpolysiloxanes with dimethylvinylsiloxane groups at both ends of the molecular chain; dimethylsiloxane-methylvinylsiloxane copolymers with dimethylvinylsiloxane groups at both ends of the molecular chain; dimethylsiloxane-methylvinylsiloxane-methylphenylsiloxane copolymers with dimethylvinylsiloxane groups at both ends of the molecular chain; containing R 1 2SiO 1 / 2 The siloxane unit represented by R and the siloxane unit represented by R 1 2R 2 SiO 1 / 2 The siloxane unit represented and the siloxane unit composed of SiO 4 / 2 Organopolysiloxane copolymers containing siloxane units; comprising R 1 2R 2 SiO 1 / 2 The siloxane unit represented and the siloxane unit composed of SiO 4 / 2Organopolysiloxane copolymers containing siloxane units; comprising R 1 R 2 SiO 2 / 2 The siloxane unit represented by R and the siloxane unit represented by R 1 SiO 3 / 2 The siloxane unit represented by R or made of 2 SiO 3 / 2 The organopolysiloxane copolymer representing the siloxane unit; and mixtures of two or more of the foregoing, but not limited thereto. Here, R 1 Or R 2 This refers to a hydrocarbon group other than an alkenyl group, specifically an alkyl group, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, or heptyl; an aryl group, such as phenyl, tolyl, xylyl, or naphthyl; an aralkyl group, such as benzyl or phenethyl; a halogen-substituted alkyl group, such as chloromethyl, 3-chloropropyl, or 3,3,3-trifluoropropyl; and so on. Furthermore, R... 2 It is an alkenyl group, which can specifically be vinyl, allyl, butenyl, pentenyl, hexenyl, or heptenyl, etc.

[0064] More specific examples of (2) organopolysiloxanes that may be used in this application may include: methylhydropolysiloxanes with trimethylsiloxane groups at both ends of the molecular chain; dimethylsiloxane-methylhydro copolymers with trimethylsiloxane groups at both ends of the molecular chain; dimethylsiloxane-methylhydrosiloxane-methylphenylsiloxane copolymers with trimethylsiloxane groups at both ends of the molecular chain; dimethylpolysiloxanes with dimethylhydrosiloxane groups at both ends of the molecular chain; dimethylsiloxane-methylphenylsiloxane copolymers with dimethylhydrosiloxane groups at both ends of the molecular chain; methylphenylpolysiloxanes with dimethylhydrosiloxane groups at both ends of the molecular chain; methylphenylpolysiloxanes containing R 1 3SiO 1 / 2 The siloxane unit represented by R 1 2HSiO 1 / 2 The siloxane unit represented and the siloxane unit composed of SiO 4 / 2 Organopolysiloxane copolymers containing siloxane units; comprising R 1 2HSiO 1 / 2 The siloxane unit represented and the siloxane unit composed of SiO 4 / 2 Organopolysiloxane copolymers containing siloxane units; comprising R 1 HSiO 2 / 2 The siloxane unit represented by R and the siloxane unit represented by R 1 SiO 3 / 2 The siloxane unit represented is or is composed of HSiO 3 / 2 The organopolysiloxane copolymer representing the siloxane unit; and mixtures of two or more of the foregoing, but not limited thereto. Here, R 1It is a hydrocarbon group other than an alkenyl group, which can specifically be an alkyl group, such as methyl, ethyl, propyl, butyl, pentyl, hexyl or heptyl; an aryl group, such as phenyl, tolyl, xylyl or naphthyl; an aralkyl group, such as benzyl or phenethyl; a halogen-substituted alkyl group, such as chloromethyl, 3-chloropropyl or 3,3,3-trifluoropropyl; and so on.

[0065] Unless otherwise stated, when measuring temperature affects the results, the physical properties mentioned in this specification refer to those measured at room temperature. Room temperature means the natural temperature without heating or cooling, typically any temperature in the range of about 10°C to 30°C, or about 23°C, or about 25°C. Furthermore, unless otherwise stated in this specification, the unit of temperature is °C. When measuring pressure affects the results, the physical properties mentioned in this specification refer to those measured at atmospheric pressure. Atmospheric pressure means the natural pressure without pressurization or depressurization, where atmospheric pressure is typically referred to as about 1 atmosphere.

[0066] The upper and lower substrates of the liquid crystal cell can be attached using a pressure-sensitive adhesive layer. Specifically, the pressure-sensitive adhesive layer of the upper substrate and the spacers of the lower substrate can be attached. When an alignment film is formed on the spacers of the lower substrate, the region of the alignment film corresponding to the spacers can be attached to the pressure-sensitive adhesive layer of the upper substrate.

[0067] Spacers maintain the gap between the upper and lower substrates. Liquid crystal regions can exist in areas where no spacers exist between the upper and lower substrates. The spacers are spacers in the shape of partition walls, and liquid crystal compounds can exist in regions separated by partition walls (regions without partition walls). Regions containing liquid crystal compounds can be called liquid crystal regions.

[0068] Liquid crystal compounds can switch their orientation states by applying a voltage. As liquid crystal compounds, those whose alignment direction can be changed by applying an external force can be used. In this specification, the term "external force" can refer to any external factor that can affect the behavior of the material contained in the liquid crystal region, such as an external voltage. Therefore, a state without any external force can mean a state in which no external voltage is applied.

[0069] The type and physical properties of the liquid crystal compound can be appropriately selected considering the purpose of this application. In one example, the liquid crystal compound can be a nematic liquid crystal or a smectic liquid crystal. A nematic liquid crystal can refer to a liquid crystal in which rod-shaped liquid crystal molecules are arranged parallel to each other along the long axis of the liquid crystal molecules but their positions are not regular. A smectic liquid crystal can refer to a liquid crystal in which rod-shaped liquid crystal molecules are regularly arranged to form a layered structure and are regularly parallel to each other along the long axis. According to one example of this application, the liquid crystal compound can be a nematic liquid crystal compound.

[0070] As a nematic liquid crystal compound, a liquid crystal compound can be selected that has a clearing point of, for example, 40°C or higher, 50°C or higher, 60°C or higher, 70°C or higher, 80°C or higher, 90°C or higher, 100°C or higher, or 110°C or higher, or has a phase transition point (i.e., a phase transition point from the nematic phase to the isotropic phase) within the above ranges. In one example, the clearing point or phase transition point can be 160°C or lower, 150°C or lower, or 140°C or lower.

[0071] Liquid crystal compounds can be non-reactive liquid crystal compounds. Non-reactive liquid crystal compounds can mean liquid crystal compounds that do not have polymerizable groups. Polymerizable groups can be exemplified as acryloyl, acryloyloxy, methacryloyl, methacryloyloxy, carboxyl, hydroxyl, vinyl, or epoxy groups, but are not limited thereto, and can include functional groups known to be polymerizable groups.

[0072] The dielectric constant anisotropy of a liquid crystal compound can be positive or negative. The absolute value of the dielectric constant anisotropy of the liquid crystal compound can be appropriately selected considering the purpose of this application. The term "dielectric constant anisotropy (Δε)" can refer to the difference (ε / -ε⊥) between the horizontal dielectric constant (ε / ) and the vertical dielectric constant (ε⊥) of the liquid crystal. In this specification, the term horizontal dielectric constant (ε / ) means the dielectric constant measured along the direction of the electric field when a voltage is applied such that the director of the liquid crystal is substantially horizontal to the direction of the electric field caused by the applied voltage, and the term vertical dielectric constant (ε⊥) means the dielectric constant measured along the direction of the electric field when a voltage is applied such that the director of the liquid crystal is substantially perpendicular to the direction of the electric field caused by the applied voltage. The dielectric constant anisotropy of liquid crystal molecules can be in the range of 5 to 25.

[0073] The refractive index anisotropy (Δn) of the liquid crystal compound can be appropriately selected with consideration of the purposes of this application. In this specification, the term "refractive index anisotropy" can refer to the unusual refractive index (n) of the liquid crystal compound. e ) and ordinary refractive index (n o The difference (n) e -n o The refractive index anisotropy of the liquid crystal compound can be, for example, from 0.01 to 0.3. The refractive index anisotropy can be 0.01 or greater, 0.05 or greater, or 0.07 or greater, and can be 0.3 or less, 0.2 or less, 0.15 or less, or 0.13 or less.

[0074] The thickness of the liquid crystal region (liquid crystal layer) can be determined based on the height of the spacers (separators). There are no particular limitations on the thickness of the liquid crystal region; for example, the thickness of the liquid crystal region or the height of the spacers (separators) can be approximately 0.01 μm or greater, 0.05 μm or greater, 0.1 μm or greater, 0.5 μm or greater, 1 μm or greater, 1.5 μm or greater, 2 μm or greater, 2.5 μm or greater, 3 μm or greater, 3.5 μm or greater, 4 μm or greater, 4.5 μm or greater, 5 μm or greater, 5.5 μm or greater, 6 μm or greater, 6.5 μm or greater, 7 μm or greater, 7.5 μm or greater, 8 μm or greater, 8.5 μm or greater, 9 μm or greater, or 9.5 μm or greater. There is no particular limit to the thickness of the liquid crystal region or the height of the spacers (separators), which can generally be about 30 μm or less, 25 μm or less, 20 μm or less, or 15 μm or less.

[0075] The liquid crystal cell can switch the orientation state of the liquid crystal region according to the applied voltage. In one example, the liquid crystal region may have a first orientation state when no voltage is applied to the liquid crystal cell, and a second orientation state different from the first orientation state when a voltage is applied to the liquid crystal cell. The first orientation state and / or the second orientation state may be exemplified as a horizontal orientation state, a vertical orientation state, a twisted orientation state, a tilted orientation state, a mixed orientation state, etc.

[0076] In this specification, "horizontal alignment state" refers to a state in which the pointer of the liquid crystal compound in the liquid crystal region is substantially parallel to the plane of the liquid crystal region, wherein, for example, the angle formed by the pointer relative to the plane of the liquid crystal region may be in the range of about -10 degrees to 10 degrees or about -5 degrees to 5 degrees, or may be about 0 degrees.

[0077] In this specification, "vertical orientation state" refers to the state in which the pointer of the liquid crystal compound in the liquid crystal region is substantially perpendicular to the plane of the liquid crystal region, wherein, for example, the angle formed by the pointer relative to the plane of the liquid crystal region may be in the range of about 80 degrees to 100 degrees or about 85 degrees to 95 degrees, or may be about 90 degrees.

[0078] In this specification, "twisted orientation state" can refer to a helical structure in which the pointers of liquid crystal compounds in the liquid crystal region are twisted along an imaginary helical axis to form a layer and are oriented. The twisted orientation state can be achieved in a vertical orientation state, a horizontal orientation state, or a tilted orientation state. That is, the vertical twisted orientation mode is the state in which each liquid crystal compound is twisted along the helical axis in a vertical orientation state to form a layer; the horizontal twisted orientation mode is the state in which each liquid crystal compound is twisted along the helical axis in a horizontal orientation state to form a layer; and the tilted twisted orientation mode is the state in which each liquid crystal compound is twisted along the helical axis in a tilted orientation state to form a layer.

[0079] In this specification, "mixed orientation state" may refer to an orientation state in which the tilt angle (which is the angle formed by the direction vector of the liquid crystal compound in the liquid crystal region relative to the plane of the liquid crystal region) gradually increases or decreases along the thickness direction of the liquid crystal region.

[0080] In one instance, the first orientation state can be a twisted orientation state. That is, the liquid crystal region can switch between a twisted orientation and an orientation state different from a twisted orientation by applying external energy.

[0081] In one example, the liquid crystal region can switch between a twisted alignment state and a vertical alignment state. In another example, the liquid crystal region can be in a vertical alignment state when no voltage is applied, and in a twisted alignment state when a voltage is applied. The twisted alignment state can be a horizontal twisted alignment state.

[0082] In one example, when the liquid crystal compound is present in a vertically aligned state, both a vertical alignment state relative to the tilted surface of the alignment film and a vertical alignment state relative to the lower surface of the alignment film can be achieved. When the liquid crystal compound is vertically aligned relative to the tilted surface of the alignment film, it can also be tilted relative to the substrate layer. In this case, by reducing the phase difference of the liquid crystal, light leakage caused by misalignment with the polarization direction of the polarizer can be suppressed.

[0083] The liquid crystal region may also contain a chiral dopant. When the liquid crystal region contains a chiral dopant, a twisted orientation state can be achieved. Chiral dopants that can be contained in the liquid crystal region can be used without particular limitation, as long as they are chiral dopants capable of inducing the desired rotation (twisting) without degrading the liquid crystal properties, such as nematic regularity. The chiral dopant used to induce rotation in the liquid crystal compound needs to contain at least chirality in its molecular structure. Examples of chiral dopant include: for example, compounds having one or two or more asymmetric carbons; compounds having asymmetric sites on heteroatoms, such as chiral amines or chiral sulfoxides; or compounds having axially asymmetric and optically active sites, such as cumulative polyenes or binatol. The chiral dopant can be, for example, a low molecular weight compound with a molecular weight of 1,500 or less. Commercially available chiral nematic liquid crystals can also be used as chiral dopants, for example, the chiral doped liquid crystal S811 from Merck Co., Ltd. or LC756 from BASF.

[0084] The application ratio of the chiral dopant can be selected to achieve the desired pitch (P). Typically, the chiral dopant content (wt%) can be calculated using equation 100 / (HTP×P), where HTP represents the helical twisting force of the chiral dopant, with units in μm. -1 P can be the pitch of the liquid crystal in a twisted orientation state, where the unit can be μm. The pitch (P) of the liquid crystal region can be measured using a wedge cell measurement method, and specifically, using the method described in D. Podolskyy et al., Simple method for accurate measurements of the cholesteric pitch using a “stripe-wedge” Grandjean-Cano cell (Liquid Crystals, Vol. 35, No. 7, July 2008, 789-791). The HTP value can be measured using the wedge cell measurement method described above. Alternatively, the HTP value can usually be provided by the suppliers of the liquid crystal and the chiral dopant. The content of the chiral dopant can be determined by considering the desired pitch with reference to the above methods.

[0085] In one example, the pitch (in μm) of the liquid crystal in a twisted orientation state can range from 15 μm to 50 μm. Specifically, the pitch can be 16 μm or greater, 17 μm or greater, 18 μm or greater, 19 μm or greater, or 20 μm or greater, and can be 50 μm or less, 45 μm or less, 40 μm or less, 35 μm or less, or 30 μm or less.

[0086] The liquid crystal region may also contain dichroic dyes. Dichroic dyes can control the variable light transmittance characteristics of the liquid crystal region. In this specification, the term "dye" may mean a material capable of strongly absorbing and / or deforming light within at least part or all of the visible light region (e.g., in the wavelength range of 400 nm to 700 nm), and the term "dichroic dye" may mean a material capable of anisotropically absorbing light within at least part or all of the visible light region.

[0087] The liquid crystal region containing the liquid crystal compound and the dichroic dye can be a GHLC layer (guest-host liquid crystal region). In this specification, "GHLC layer (guest-host liquid crystal region)" can refer to a functional layer in which the dichroic dyes are arranged together according to the liquid crystal compound, thereby exhibiting anisotropic light absorption characteristics relative to the alignment direction of the dichroic dyes and in a direction perpendicular to that alignment direction. For example, a dichroic dye is a substance whose light absorption rate changes with the polarization direction. If the absorption rate for light polarized in the long axis direction is large, it can be called a p-type dye, and if the absorption rate for light polarized in the short axis direction is large, it can be called an n-type dye. In one example, when a p-type dye is used, polarized light vibrating in the long axis direction of the dye can be absorbed, while polarized light vibrating in the short axis direction of the dye can be less absorbed and transmitted. In the following text, unless otherwise stated, the dichroic dye is considered to be a p-type dye.

[0088] As dichroic dyes, for example, known dyes that are known to have the property of being able to align according to the orientation state of the liquid crystal compound through the so-called guest-host effect can be selected and used. Examples of such dichroic dyes include azo dyes, anthraquinone dyes, methylene dyes, azomethyl base dyes, cyanine dyes, naphthoquinone dyes, tetraazine dyes, phenylene dyes, tetranaphthalene dyes, benzothiadiazole dyes, diketopyrrolopyrrole dyes, squaric acid cyanine dyes, or pyrrole methylbenzene dyes, but the dyes applicable to this application are not limited to these.

[0089] Dichroic dyes can be used with a dichroic ratio (i.e., a value obtained by dividing the absorptivity of polarized light parallel to the long axis of the dichroic dye by the absorptivity of polarized light parallel to the direction perpendicular to the long axis) of 5 or greater, 6 or greater, or 7 or greater. The dichroic dye can satisfy the said dichroic ratio for at least a portion or any of the wavelengths in the visible light region (e.g., about 380 nm to 700 nm or about 400 nm to 700 nm). The upper limit of the dichroic ratio can be, for example, about 20 or less, 18 or less, 16 or less, or about 14 or less.

[0090] The content of dichroic dyes in the liquid crystal region can be appropriately selected considering the purpose of this application. For example, the content of dichroic dyes in the liquid crystal region can be 0.2% by weight or more. Specifically, the content of dichroic dyes can be 0.5% by weight or more, 1% by weight or more, 2% by weight or more, or 3% by weight or more. The upper limit of the content of dichroic dyes can be, for example, 10% by weight or less, 9% by weight or less, 8% by weight or less, 6% by weight or less, or 5% by weight or less. When the content of dichroic dyes in the liquid crystal region is too low, it may be difficult to exhibit the desired variable transmittance characteristics, and when the content of dichroic dyes in the liquid crystal region is too high, there is a risk of precipitation. Therefore, the content of dichroic dyes within the above ranges can be advantageous.

[0091] The upper substrate may further include a first electrode layer 302 between the first substrate layer 301 and the pressure-sensitive adhesive layer 303. The first electrode layer 302 may contact the inner surface of the first substrate layer 301. The pressure-sensitive adhesive layer 303 may contact the inner surface of the first electrode layer 302. The lower substrate of the liquid crystal cell may further include a second electrode layer 102 between the second substrate layer 201 and the spacer 103. The second electrode layer 102 may contact the inner surface of the second substrate layer 201. The spacer 103 may contact the inner surface of the second electrode layer 202.

[0092] The first and second electrode layers can be used to provide external effects, such as the application of an electric field, causing the material contained in the liquid crystal region to transmit or block incident light. In one example, the first and / or second electrode layers may comprise conductive polymers, conductive metals, conductive nanowires, or metal oxides such as ITO (indium tin oxide), but are not limited thereto. The first and / or second electrode layers can be formed, for example, by depositing conductive polymers, conductive metals, conductive nanowires, or metal oxides such as ITO (indium tin oxide).

[0093] In this specification, the combination of a first substrate layer, a first electrode layer, and a pressure-sensitive adhesive layer may be referred to as the upper substrate, and the combination of a second substrate layer, a second electrode layer, a spacer, and an alignment film may be referred to as the lower substrate. The lower substrate may also include an undercoat layer. In a liquid crystal cell, the upper substrate may not include a separate alignment film other than the pressure-sensitive adhesive layer, and the lower substrate may include an alignment film. In a liquid crystal cell, the alignment film may contact the liquid crystal layer.

[0094] The optical device may also include polarizers. In one example, the optical device may further include a first polarizer disposed on the outer side of an upper substrate and a second polarizer disposed on the outer side of a lower substrate. The first polarizer may be attached to the outer surface of the upper substrate, and the second polarizer may be attached to the outer surface of the lower substrate. For the attachment of the substrate and the polarizer, a known adhesive layer used in the manufacture of optical devices may be applied.

[0095] Each liquid crystal region can exist inside the upper and lower substrates.

[0096] In this specification, the term polarizer means a film, sheet, or element that has a polarizing function. A polarizer is a functional element capable of extracting light vibrating in one direction from incident light vibrating in multiple directions.

[0097] The first polarizer and the second polarizer can each be either an absorptive polarizer or a reflective polarizer. In this specification, an absorptive polarizer refers to an element that exhibits selective transmission and absorption characteristics with respect to incident light. An absorptive polarizer can transmit, for example, light vibrating in one direction from incident light vibrating in multiple directions, and can absorb light vibrating in other directions. Similarly, in this specification, a reflective polarizer refers to an element that exhibits selective transmission and reflection characteristics with respect to incident light. A reflective polarizer can transmit, for example, light vibrating in one direction from incident light vibrating in multiple directions, and can reflect light vibrating in other directions.

[0098] As an absorptive polarizer, for example, a polarizing layer in which iodine is dyed on a polymer stretch film such as a PVA (polyvinyl alcohol) stretch film can be used, or a guest-host polarizing layer can be used with a liquid crystal polymerized in an oriented state as the host and a dichroic dye arranged according to the orientation of the liquid crystal as the guest, but is not limited thereto.

[0099] As a reflective polarizer, for example, a reflective polarizing layer called a so-called DBEF (Dual Brightness Enhancement Film) can be used, or a reflective polarizing layer formed by coating a liquid crystal compound such as LLC (Lyotropic liquid crystal), but it is not limited to these.

[0100] The polarizer can be a linear polarizer. In this specification, a linear polarizer means a light source in which the selectively transmitted light is linearly polarized light vibrating in either direction, and the selectively absorbed or reflected light is linearly polarized light vibrating in a direction perpendicular to the vibration direction of the linearly polarized light. In the case of an absorption-type linear polarizer, the light transmission axis and the light absorption axis can be perpendicular to each other. In the case of a reflection-type linear polarizer, the light transmission axis and the light reflection axis can be perpendicular to each other.

[0101] The transmittance of the first and second polarizers for light with a wavelength of 550 nm can each be in the range of 40% to 50%. This transmittance can refer to the individual transmittance of the polarizer for light with a wavelength of 550 nm. The individual transmittance of the polarizer can be measured using, for example, a spectrometer (V7100, manufactured by Jasco). For example, the individual transmittance can be calculated after measuring each transmittance with the polarizer sample (without the upper and lower protective films) mounted on the device, using air as the baseline, and with the axis of the polarizer sample perpendicular and horizontally aligned with the axis of the reference polarizer.

[0102] The light transmission axes of the first polarizer and the second polarizer can be perpendicular to each other. Specifically, the angle formed by the light transmission axes of the first polarizer and the second polarizer can be in the range of 80 degrees to 100 degrees or 85 degrees to 95 degrees, or it can be about 90 degrees. When using the substrate for the optical device of this application, when the light transmission axes of the first polarizer and the second polarizer are perpendicular to each other, light leakage caused by misalignment between the orientation direction of the liquid crystal and the polarization direction of the polarizer can be effectively suppressed.

[0103] Optical devices may also include various functional layers as needed. Examples of functional layers include, but are not limited to, protective films for polarizers, anti-reflective films, retardation films, hard coatings, and anti-fouling layers.

[0104] The optical device can be a variable transmittance device. A variable transmittance device can switch between at least two different transmittance states. In one example, the variable transmittance device can be a device capable of switching between a transparent mode state and a black mode state.

[0105] The transmittance of the variable transmittance device in transparent mode can be at least 10% or greater, 15% or greater, 20% or greater, 25% or greater, 30% or greater, 35% or greater, 40% or greater, 45% or greater, 50% or greater, 55% or greater, 60% or greater, 65% or greater, 70% or greater, 75% or greater, or approximately 80% or greater. In another example, the transmittance in transparent mode can also be approximately 100% or less, 95% or less, 90% or less, or approximately 85% or less. However, higher transmittance in transparent mode is more advantageous, so there is no particular upper limit.

[0106] In black mode, the transmittance of the variable transmittance device can be 60% or less, 55% or less, 50% or less, 45% or less, 40% or less, 35% or less, 30% or less, 25% or less, 20% or less, 15% or less, 10% or less, or 5% or less. In another example, the transmittance in black mode can also be around 0% or more, 5% or more, 10% or more, 15% or more, 20% or more, or 25% or more. However, lower transmittance in black mode is more advantageous, so there is no particular limitation on the lower limit of transmittance in black mode.

[0107] Transmittance can be, for example, the transmittance of direct light. Direct light transmittance is the percentage of light transmitted in the same direction as the incident direction to the light incident on the device. For example, if the device is in the form of a film or sheet, transmittance can be defined as the percentage of light incident in a direction parallel to the normal to the surface of the film or sheet that is transmitted through the device in that direction.

[0108] Transmittance can be the transmittance for any wavelength in the visible light region (e.g., the range of about 400 nm to 700 nm or about 380 nm to 780 nm), or the transmittance for the entire visible light region, the maximum or minimum transmittance for the entire visible light region, or the average transmittance for the visible light region.

[0109] The optical device can be used in a variety of applications, such as eye-wearing devices like sunglasses, AR (Augmented Reality) or VR (Virtual Reality) eye-wearing devices, building exteriors, or vehicle sunroofs. In one example, the optical device itself can be a vehicle sunroof. For instance, in a car body including at least one opening, the optical device can be installed as a sunroof in the opening to be used, or a sunroof including the optical device can be installed for use.

[0110] Beneficial effects

[0111] This application relates to substrates for optical devices. This application can provide a substrate for optical devices that appropriately maintains the cell gap between the upper and lower substrates of a liquid crystal cell, has excellent adhesion between the upper and lower substrates, and exhibits excellent visibility by improving flicker and rainbow phenomena. Attached Figure Description

[0112] Figure 1 An exemplary substrate for an optical device of this application is shown.

[0113] Figure 2 An exemplary substrate for an optical device of this application is shown.

[0114] Figure 3 An exemplary substrate for an optical device of this application is shown.

[0115] Figure 4 Exemplary examples include Figure 1 The liquid crystal cell is used as a substrate for optical devices.

[0116] Figure 5 Exemplary examples include Figure 2 The liquid crystal cell is used as a substrate for optical devices.

[0117] Figure 6 Exemplary examples include Figure 3 The liquid crystal cell is used as a substrate for optical devices.

[0118] Figure 7 These are images observing the flashing and rainbow phenomena of the embodiments and comparative examples.

[0119] Figure 8 An exemplary substrate for an optical device of a comparative example is shown. Detailed Implementation

[0120] The present application will be described in detail below through embodiments, but the scope of the present application is not limited to the following embodiments.

[0121] Measurement Example 1. Measurement of Inclination Angle

[0122] The tilt angle was measured using FE-SEM (Field Emission Scanning Electron Microscopy) through cross-sectional analysis. For FE-SEM cross-sectional analysis, a specimen cut to a width × length of 20 mm × 20 mm was prepared as the measurement object. FE-SEM cross-sectional analysis was performed on the specimen under the following conditions: accelerating voltage: 5 kV; beam intensity: 10; magnification: ×5000. Based on the FE-SEM analysis image, the angle was measured only from the region of constant slope angle on the upper surface of the measurement object.

[0123] Example 1

[0124] Manufacturing of the upper substrate

[0125] An OCA-type pressure-sensitive adhesive resin (KR3700, ShinEtsu) was mixed in toluene solvent to achieve a solids content concentration of 25% by weight. To prepare a pressure-sensitive adhesive composition, 15 parts by weight of a crosslinking agent (tetra(dimethylsiloxy)silane, Gelest) and 1 part by weight of a platinum catalyst (CAT-PL-56, ShinEtsu) were added relative to 100 parts by weight of the resin. The pressure-sensitive adhesive composition was then coated onto a fluorinated release film (FSC6, Nippa) and heated at 140°C for 6 minutes to form a pressure-sensitive adhesive layer with a final thickness of approximately 10 μm. The pressure-sensitive adhesive layer was then laminated onto the ITO layer of a PET-ITO film to create the upper substrate. The PET-ITO film is a film in which an ITO (indium tin oxide) layer is deposited on a highly stretchable PET (polyethylene terephthalate) film (OCF, SKC) with a thickness of approximately 30 nm. Its dimensions are 300 mm x 300 mm (width x length) and its total thickness is approximately 145 μm. The fabricated upper substrate has a structure in which the PET film / ITO layer / pressure-sensitive adhesive layer / release film are laminated in this order.

[0126] Manufacturing of the lower substrate

[0127] An acrylic resin composition (KAD-03, MINUTA Tech) was coated onto the ITO layer of the same PET-ITO film used in the upper substrate, and then spacers with a tilt angle of approximately 85 degrees were formed by photolithography. The spacers have a random pattern obtained by randomizing a regular hexagonal pattern (honeycomb pattern) with a spacing of approximately 350 μm between two opposite sides. The height of the spacers in the spacers is approximately 6 μm, and the linewidth of the spacers (based on the upper surface of the spacers) is approximately 15 μm. Subsequently, a vertical alignment film (5661LB3, Nissan) was coated such that the thickness of the lower region between the spacers is approximately 400 nm, and then the lower substrate was fabricated by rubbing with a rubbing cloth in one direction. The thickness of the upper region of the vertical alignment film on the spacers (the distance from the upper surface a1 of the vertical alignment film to the upper surface b1 of the spacer) is approximately 80 nm, and the tilt angle of the vertical alignment film is approximately 45 degrees.

[0128] Manufacturing of liquid crystal cells

[0129] A fluorine release film is peeled off from an upper substrate. A liquid crystal composition is coated onto an alignment film on a lower substrate and then laminated with the upper substrate to fabricate a liquid crystal cell. The liquid crystal composition is a mixture of a liquid crystal compound (SHN-7002XX T12, JNC) with a refractive index anisotropy (Δn) of 0.094 and negative dielectric anisotropy, and a chiral dopant (S811, Merck). The fabricated liquid crystal cell is a reverse TN mode liquid crystal cell with a cell gap of 6 μm and a chiral pitch of 20 μm.

[0130] Example 2

[0131] The liquid crystal cell was manufactured using the same method as in Example 1, except that the lower substrate was manufactured as follows. First, spacers were formed on the ITO layer of the PET-ITO film using the same method as in Example 1. Then, a vertical alignment film (5661LB3, Nissan) was coated such that the thickness of the lower region between the spacers was approximately 800 nm, and then the lower substrate was manufactured by rubbing with a rubbing cloth in one direction. The thickness of the upper region of the vertical alignment film on the spacers was approximately 150 nm, and the tilt angle of the vertical alignment film was approximately 15 degrees.

[0132] Example 3

[0133] The liquid crystal cell was manufactured using the same method as in Example 1, except that the lower substrate was manufactured as follows. First, spacers were formed on the ITO layer of the PET-ITO film using the same method as in Example 1. Then, an undercoat was formed such that the thickness of the lower region between the spacers was approximately 400 nm. The undercoat was formed by coating a UV-curable acrylic resin composition thereon, followed by UV-A ultraviolet light at 400 mJ / cm². 2It is formed by irradiation to cure. The UV-curable acrylic resin composition comprises 8.7 wt% tricyclodecanediethanol diacrylate (MIRAMER M262, MIWON), 2.9 wt% acrylate mixture (product number: 246794, Sigma-Aldrich), 2.9 wt% pentaerythritol tetra(3-mercaptobutyrate) (KarenzMT™PE1, Resonac), and 0.4 wt% initiator (Irgacure 127, BASF) as solid contents and contains PGME (propylene glycol monomethyl ether) as residual solvent. The acrylate mixture is a mixture of pentaerythritol tetraacrylate, pentaerythritol triacrylate, and trimethylolpropane triacrylate. The thickness of the upper region of the primer coating on the spacer wall (the distance from the upper surface c1 of the primer coating to the upper surface b1 of the spacer) is about 160 nm, and the tilt angle after the primer coating is formed (the tilt angle of the primer coating) is about 51 degrees. Subsequently, a vertical alignment film (5661LB3, Nissan) was coated to achieve a thickness of approximately 100 nm in the lower region between the spacers, and then the substrate was fabricated by rubbing with a rubbing cloth in one direction. The thickness of the vertical alignment film in the upper region on the spacers was approximately 20 nm, and the tilt angle of the vertical alignment film was approximately 41 degrees.

[0134] Example 4

[0135] The liquid crystal cell was manufactured using the same method as in Example 1, except that the lower substrate was manufactured as follows. First, spacers were formed on the ITO layer of the PET-ITO film using the same method as in Example 1. Then, an undercoat was formed such that the thickness of the lower region between the spacers was approximately 800 nm. The undercoat was formed by coating a UV-curable acrylic resin composition and then exposing it to UV-A ultraviolet light at 400 mJ / cm². 2 The mixture was cured by irradiation. The UV-curable acrylic resin composition was the same as that used in Example 3. The thickness of the primer layer in the upper region of the spacers was about 300 nm, and the tilt angle after the primer layer was formed (tilt angle of the primer layer) was about 25 degrees. Subsequently, a vertical alignment film (5661LB3, Nissan) was coated such that the thickness of the lower region between the spacers was about 100 nm, and then the substrate was rubbed in one direction with a rubbing cloth to create the lower substrate. The thickness of the vertical alignment film in the upper region of the spacers was about 20 nm, and the tilt angle of the vertical alignment film was about 13 degrees.

[0136] Example 5

[0137] The liquid crystal cell was manufactured using the same method as in Example 1, except that the lower substrate was manufactured as follows. First, spacers were formed on the ITO layer of the PET-ITO film using the same method as in Example 1. Then, an undercoat was formed such that the thickness of the lower region between the spacers was approximately 800 nm. The undercoat was formed by coating a UV-curable acrylic resin composition and then exposing it to UV-A ultraviolet light at 400 mJ / cm². 2 The mixture was cured by irradiation. The UV-curable acrylic resin composition was the same as that used in Example 3. The thickness of the primer layer in the upper region of the spacers was about 300 nm, and the tilt angle after the primer layer was formed (tilt angle of the primer layer) was about 25 degrees. Subsequently, a vertical alignment film (5661LB3, Nissan) was coated such that the thickness of the lower region between the spacers was about 300 nm, and then the mixture was rubbed in one direction with a rubbing cloth to create the lower substrate. The thickness of the vertical alignment film in the upper region of the spacers was about 60 nm, and the tilt angle of the vertical alignment film was about 6 degrees.

[0138] Example 6

[0139] The liquid crystal cell was manufactured using the same method as in Example 1, except that the lower substrate was manufactured as follows. First, an acrylic resin composition (KAD-03, MINUTA Tech) was coated onto the ITO layer of the same PET-ITO film used in the upper substrate of Example 1, and then spacers with a tilt angle of about 50 degrees were formed by photolithography. The spacers had a random pattern obtained by randomizing a regular hexagonal pattern (honeycomb pattern) with a gap of about 350 μm between two opposite sides. The height of the spacers was about 6 μm, and the linewidth of the spacers (based on the upper surface of the spacers) was about 15 μm. Subsequently, a vertical alignment film (5661LB3, Nissan) was coated such that the thickness of the lower region between the spacers was about 100 nm, and then the lower substrate was manufactured by rubbing in one direction with a rubbing cloth. The thickness of the vertical alignment film in the upper region on the spacers was about 20 nm, and the tilt angle of the vertical alignment film was about 41 degrees.

[0140] Example 7

[0141] The liquid crystal cell was manufactured using the same method as in Example 1, except that the lower substrate was manufactured as follows. First, spacers were formed on the ITO layer of the PET-ITO film using the same method as in Example 1. Then, an undercoat was formed such that the thickness of the lower region between the spacers was approximately 800 nm. The undercoat was formed by coating a UV-curable acrylic resin composition and then exposing it to UV-A ultraviolet light at 400 mJ / cm². 2It is formed by irradiation to cure. The UV-curable acrylic resin composition comprises 8.7 wt% tricyclodecanediethanol diacrylate (MIRAMER M262, MIWON), 2.9 wt% acrylate mixture (product number: 246794, Sigma-Aldrich), 2.9 wt% pentaerythritol tetra(3-mercaptobutyrate) (KarenzMT™PE1, Resonac), and 0.4 wt% initiator (Irgacure 127, BASF) as solid contents and contains PGME (propylene glycol monomethyl ether) as residual solvent, and also contains lactam black (SML-333, SCK) as black dye, such that the weight ratio of solid contents to black dye is 9:1. The thickness of the base coat in the upper region on the spacer wall is about 300 nm, and the tilt angle after the base coat is formed (the tilt angle of the base coat) is about 25 degrees. Subsequently, a vertical alignment film (5661LB3, Nissan) was coated to achieve a thickness of approximately 100 nm in the lower region between the spacers, and then the substrate was fabricated by rubbing with a rubbing cloth in one direction. The thickness of the vertical alignment film in the upper region on the spacers was approximately 20 nm, and the tilt angle of the vertical alignment film was approximately 13 degrees.

[0142] Example 8

[0143] The liquid crystal cell was manufactured using the same method as in Example 1, except that the lower substrate was manufactured as follows. First, spacers were formed on the ITO layer of the PET-ITO film using the same method as in Example 1. Then, an undercoat was formed such that the thickness of the lower region between the spacers was approximately 800 nm. The undercoat was formed by coating a UV-curable acrylic resin composition and then exposing it to UV-A ultraviolet light at 400 mJ / cm². 2It is formed by irradiation to cure. The UV-curable acrylic resin composition comprises 8.7 wt% tricyclodecanediethanol diacrylate (MIRAMER M262, MIWON), 2.9 wt% AE47K, 2.9 wt% pentaerythritol tetra(3-mercaptobutyrate) (KarenzMT™PE1, Resonac), and 0.4 wt% initiator (Irgacure 127, BASF) as solid contents and PGME (propylene glycol monomethyl ether) as residual solvent, and also contains lactam black (SML-333, SCK) as black dye, such that the weight ratio of solid contents to black dye is about 6:4. The thickness of the base coat in the upper region on the spacer wall is about 300 nm, and the tilt angle after the base coat is formed (the tilt angle of the base coat) is about 25 degrees. Subsequently, a vertical alignment film (5661LB3, Nissan) was coated to achieve a thickness of approximately 100 nm in the lower region between the spacers, and then the substrate was fabricated by rubbing with a rubbing cloth in one direction. The thickness of the vertical alignment film in the upper region on the spacers was approximately 20 nm, and the tilt angle of the vertical alignment film was approximately 13 degrees.

[0144] Comparative Example 1

[0145] The liquid crystal cell was manufactured using the same method as in Example 1, except that the lower substrate was manufactured as follows. First, spacers were formed on the ITO layer of the PET-ITO film using the same method as in Example 1. Then, a vertical alignment film (5661LB3, Nissan) was coated such that the thickness of the lower region between the spacers was approximately 100 nm, and the lower substrate was then rubbed in one direction using a rubbing cloth. The thickness of the upper region of the vertical alignment film on the spacers was approximately 20 nm, and the tilt angle of the vertical alignment film was approximately 68 degrees.

[0146] Comparative Example 2

[0147] The liquid crystal cell was manufactured using the same method as in Example 1, except that the lower substrate was manufactured as follows. First, spacers were formed on the ITO layer of the PET-ITO film using the same method as in Example 1. Then, a vertical alignment film (5661LB3, Nissan) was coated such that the thickness of the lower region between the spacers was approximately 300 nm, and then the lower substrate was manufactured by rubbing with a rubbing cloth in one direction. The thickness of the upper region of the vertical alignment film on the spacers was approximately 60 nm, and the tilt angle of the vertical alignment film was approximately 51 degrees.

[0148] Comparative Example 3

[0149] The liquid crystal cell was manufactured using the same method as in Example 1, except that the lower substrate was manufactured as follows. First, spacers were formed on the ITO layer of the PET-ITO film using the same method as in Example 1. Subsequently, an undercoat was formed such that the thickness of the lower region between the spacers was approximately 200 nm. The undercoat was formed by coating a UV-curable acrylic resin composition and then applying it at 400 mJ / cm². 2 Curing was performed by irradiation with UV-A ultraviolet light. The UV-curable acrylic resin composition was the same as that used in Example 3. The thickness of the primer layer in the upper region of the spacers was about 80 nm, and the tilt angle after the primer layer was formed (tilt angle of the primer layer) was about 60 degrees. Subsequently, a vertical alignment film (5661LB3, Nissan) was coated such that the thickness of the lower region between the spacers was about 100 nm, and then the substrate was rubbed in one direction with a rubbing cloth to create the lower substrate. The thickness of the vertical alignment film in the upper region of the spacers was about 20 nm, and the tilt angle of the vertical alignment film was about 49 degrees.

[0150] Evaluation Example 1. Evaluation of Flashes and Rainbows

[0151] An optical device is manufactured by attaching a first polarizer to one side of a liquid crystal cell manufactured in each of the embodiments and comparative examples, and attaching a second polarizer to the other side of the liquid crystal cell. As each of the first and second polarizers, an iodine-dyed polyvinyl alcohol-based stretched film is used. The transmission axes of the first and second polarizers are attached to form approximately 90 degrees. When the optical device is observed relative to sunlight (in the order of sunlight, optical device, and observer), it is determined whether flashes and rainbows are observed. Flashes and rainbows can be observed with the naked eye, and... Figure 7 Images of flashes and rainbows are shown (A to C: Comparative Examples 1 to 3, D to K: Examples 1 to 8). Flashes and rainbows were observed in Comparative Examples 1 to 3, but not in Examples 1 to 8. The rainbows observed were circular, and the flashes were blurred due to flickering. Since the primary cause of rainbows is flashing, it can be determined that a strong rainbow is accompanied by a strong flash.

[0152] In the cases of Examples 1 to 8, such as Figures 1 to 3 As shown, the liquid crystal 20a on the lower surface a3 of the alignment film is typically oriented perpendicularly to the substrate layer 101, and the liquid crystal 20b on the side surface a2 of the alignment film is oriented obliquely due to the tilt angle of the alignment film, so that it does not affect the polarization direction of the polarizer and therefore does not cause flash or rainbow phenomena. On the other hand, in the cases of Comparative Examples 1 to 3, as Figure 8As shown, the liquid crystal 20a on the lower surface a3 of the alignment film and the liquid crystal 20b on the side surface a2 of the alignment film are vertically aligned. The optical axis of the vertically aligned liquid crystal 20b on the side surface a2 of the alignment film becomes horizontal relative to the substrate layer 101, and at the same time affects the polarization direction of the polarizer, which seems to cause flash and rainbow phenomena.

[0153] [Explanation of reference numerals in the attached figures]

[0154] 101: Substrate layer (second substrate layer), 102: Electrode layer (second electrode layer), 103: Spacer, 104: Alignment film, 105: Undercoat layer, a1: Upper surface of alignment film, a2: Side surface of alignment film (tilted surface), a3: Lower surface of alignment film, b1: Upper surface of spacer, b2: Side surface of spacer (tilted surface), c1: Upper surface of undercoat layer, c2: Side surface of undercoat layer (tilted surface), c3: Lower surface of undercoat layer, θa: Tilt angle of alignment film, θb: Tilt angle of spacer, θc: Tilt angle of undercoat layer, 301: First substrate layer, 302: Second electrode layer, 303: Pressure-sensitive adhesive layer, 200: Liquid crystal layer

Claims

1. A substrate for an optical device, comprising a substrate layer, spacers, and an alignment film, wherein the surface of the alignment film includes an upper surface, a lower surface, and an inclined surface between the upper surface and the lower surface, and the inclination angle formed by the upper surface of the alignment film and the inclined surface of the alignment film is 47 degrees or less.

2. The substrate for an optical device according to claim 1, wherein the spacer is a spacer in the shape of a partition wall.

3. The substrate for an optical device according to claim 1, wherein the surface of the spacer includes an upper surface and a side surface connected to the upper surface, and the angle formed by the upper surface and the side surface of the spacer is in the range of 30 degrees to 90 degrees.

4. The substrate for an optical device according to claim 1, wherein the spacer is present between the substrate layer and the alignment film.

5. The substrate for an optical device according to claim 1, further comprising an undercoating layer present between the spacer and the alignment film.

6. The substrate for an optical device according to claim 5, wherein the undercoat comprises a cured product of a curable resin.

7. The substrate for an optical device according to claim 5, wherein the surface of the undercoat includes an upper surface, a lower surface, and an inclined surface between the upper surface and the lower surface, and the angle formed by the upper surface of the undercoat and the inclined surface is in the range of 5 degrees to 60 degrees.

8. An optical device comprising a liquid crystal unit, the liquid crystal unit comprising: The upper substrate includes a first substrate layer and a pressure-sensitive adhesive layer; The lower substrate includes a second substrate layer, spacers, and an alignment film, wherein the surface of the alignment film includes an upper surface, a lower surface, and an inclined surface between the upper surface and the lower surface, and the inclined angle formed by the upper surface and the side surface of the alignment film is 47 degrees or less; and a liquid crystal compound is present between the upper substrate and the lower substrate.

9. The optical device of claim 8, wherein the spacer is a spacer in the shape of a partition wall, and the liquid crystal compound is present in the region separated by the partition wall.

10. The optical device according to claim 8, wherein when the liquid crystal compound is present in a vertically oriented state, both a vertically oriented state relative to the inclined surface of the alignment film and a vertically oriented state relative to the lower surface of the alignment film are realized.

11. The optical device of claim 8, wherein the liquid crystal unit further comprises a first electrode layer existing between the first substrate layer and the pressure-sensitive adhesive layer of the upper substrate, and the lower substrate further comprises a second electrode layer existing between the second substrate layer and the spacer.

12. The optical device according to claim 8 further includes a first polarizer disposed on the outer side of the upper substrate and a second polarizer disposed on the outer side of the lower substrate.

Images