Substrate for optical device

Abstract

The present application relates to a substrate for an optical device. The present application can provide a substrate for an optical device which enables maintenance of an appropriate cell gap between an upper substrate and a lower substrate of a liquid crystal cell, has excellent adhesion between the upper substrate and the lower substrate, and reduces sparkling and rainbow phenomena, thereby having excellent visibility.

Description

Substrates for optical devices

[0001] The present application relates to a substrate for an optical device.

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0120917, filed September 12, 2023, the entire contents of which are incorporated herein by reference.

[0003] In order to ensure long-term stability and large-area expandability of liquid crystal cells using flexible substrates, it is important to maintain the cell gap between the upper and lower substrates and to provide adhesive strength between the upper and lower substrates. To maintain the cell gap between the upper and lower substrates, a spacer may be used, and the spacer may have a pillar shape or a partition shape (Non-patent Document 1: "Bonding of Two Plastic Substrates for Flexible LCDs" SID Symposium Digest, 38, pp. 653-656 (2007)).

[0004] The task of the present application is to provide a substrate for an optical device in which the cell gap between the upper and lower substrates of a liquid crystal cell is appropriately maintained, excellent adhesion between the upper and lower substrates is achieved, and sparkling and rainbow phenomena are improved, thereby providing excellent visibility.

[0005] The present application relates to a substrate. The substrate is a substrate for an optical device, and can be used as a substrate for manufacturing an optical device.

[0006] Figures 1 to 3 illustrate a substrate for an optical device. The substrate may include a substrate layer (101), a spacer (103), and an alignment film (104). The substrate may include a spacer on the substrate layer, and an alignment film on the spacer. That is, the spacer may be present between the substrate layer and the alignment film.

[0007] As the substrate layer, for example, an inorganic film such as a glass film, a crystalline or amorphous silicon film, a quartz or ITO (Indium Tin Oxide) film, or a polymer film can be used, and in terms of implementing a flexible device, a polymer film can be used.

[0008] In one example, the substrate layer may be a polymer film. Examples of the polymer film include, but are not limited to, a COP (cyclo olefin copolymer) such as TAC (triacetyl cellulose); norbornene derivatives; PMMA (poly(methyl methacrylate); PC (polycarbonate); PE (polyethylene); PP (polypropylene); PVA (polyvinyl alcohol); DAC (diacetyl cellulose); PA (polyacrylate); PES (poly ether sulfone); PEEK (polyetheretherketon); PPS (polyphenylsulfone), PEI (polyetherimide); PEN (polyethylenemaphthatlate); PET (polyethyleneterephtalate); PI (polyimide); PSF (polysulfone); PA (polyarylate), or an amorphous fluororesin. The substrate layer may also include, as necessary, a coating layer of a silicon compound such as gold, silver, silicon dioxide, or silicon monoxide, or an antireflection layer.

[0009] The thickness of the substrate layer may be in the range of 10 ㎛ to 1,000 ㎛. Specifically, the thickness of the substrate layer may be 20 ㎛ or more, 40 ㎛ or more, 60 ㎛ or more, 80 ㎛ or more, or 100 ㎛ or more, and may be 900 ㎛ or less, 800 ㎛ or less, 700 ㎛ or less, 600 ㎛ or less, 500 ㎛ or less, or 400 ㎛ or less.

[0010] In one example, the substrate layer may be an optically anisotropic film. A film having such optical anisotropy typically also has anisotropic mechanical properties, and can provide a liquid crystal cell or optical device having superior durability, etc. by utilizing such anisotropy. When the optically anisotropic film is simultaneously applied as the first and second substrate layers described below, the slow axis of the first substrate layer and the slow axis of the second substrate layer may be included in the liquid crystal cell or optical device so as to be parallel or perpendicular to each other. In the present specification, the fact that the A-axis and the B-axis are perpendicular may mean that the angle formed by the A-axis and the B-axis is within a range of about 80 to 100 degrees, about 85 to 95 degrees, about 87 to 93 degrees, or about 89 to 91 degrees, or approximately 90 degrees. In this specification, the fact that the A axis and the B axis are parallel may mean that the angle formed by the A axis and the B axis is within a 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 is approximately 0 degrees.

[0011] In one example, the substrate layer may be a polymer film having an in-plane retardation value of 4,000 nm or more for light having a wavelength of 550 nm. Specifically, the in-plane retardation value may be 5,000 nm or more, 6,000 nm or more, 7,000 nm or more, 8,000 nm or more, or 9,000 nm or more, and may 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. Through this, it may be advantageous to provide a liquid crystal cell or an optical device without optical defects such as a rainbow phenomenon.

[0012] In this specification, the in-plane phase difference can be defined by the following equation 1.

[0013] [Formula 1]

[0014] Rin = (nx-ny) × d

[0015] In Equation 1, Rin is the in-plane retardation, nx is the refractive index in the slow axis direction of the polymer film, ny is the refractive index in the fast axis direction of the polymer film, and d is the thickness (nm) of the polymer film. The slow axis direction and the fast axis direction may be perpendicular to each other in the plane of the polymer film. The nx and ny may each be the refractive index for light having a wavelength of 550 nm. In the present specification, the slow axis may mean the axis in the direction in which the refractive index is the highest in the plane of the polymer film. In the present specification, the fast axis may mean the axis in the direction in which the refractive index is the lowest in the plane of the polymer film.

[0016] The above-mentioned substrate layer may be an anisotropic polymer film that has optical anisotropy imparted by stretching. Examples of the polymer film include a polyolefin film such as a polyethylene film or a polypropylene film, a cycloolefin polymer (COP) film such as a polynorbornene film, a polyvinyl chloride film, a polyacrylonitrile film, a polysulfone film, a polyacrylate film, a cellulose ester polymer film such as a poly(vinyl alcohol) (PVA) film or a triacetyl cellulose (TAC) film, a polyester film or a polycarbonate film, or a copolymer film of two or more monomers among the monomers forming the above-mentioned polymers. In one example, the film may be a polyester film such as a poly(ethylene terephthalate) (PET) film. Films exhibiting in-plane retardation within the aforementioned range are well known in the industry, and in the case of polymer films, such films not only exhibit significant optical anisotropy but also exhibit mechanical asymmetry due to stretching during the manufacturing process. Representative examples of such retardation films known in the industry include stretched polyester films, such as stretched PET (poly(ethylene terephthalate)) films.

[0017] The spacer may be a partition-shaped spacer (hereinafter referred to as a partition spacer). The partition spacer can confine the liquid crystal compound by positioning it within the internal region of the partition. This can improve the adhesion between the upper and lower substrates while maintaining the cell gap between the upper and lower substrates, and can also be advantageous in terms of the physical rigidity of the liquid crystal cell.

[0018] When the substrate on which the partition spacer is formed is observed from a normal direction, the shape of the partition may be a straight line or a curve. When the partition spacer is observed from a normal direction, the shape of the closed shape defined by the partition may be circular, elliptical, polygonal, or irregular. The closed shape defined by the partition is an area where no partition exists, and thus may also be referred to as a non-partition area. The irregular shape may refer to an unformed shape other than circular, elliptical, or polygonal. In the present specification, the normal direction may refer to a direction parallel to the thickness direction of the liquid crystal cell or optical device or the stacking direction of layers included in the liquid crystal cell or optical device.

[0019] The partition spacer may be a partition spacer having a regular pattern or a partition spacer having a random pattern. In the case of a partition spacer having a regular pattern, when the substrate on which the partition spacer is formed is observed from a normal direction, the closed shapes partitioned by the partitions may have a regular shape. The regular shape may mean that the shapes of all closed shapes are all n-gons with the same n value (n is an integer greater than or equal to 3, and the upper limit is, for example, 10 or less), and the sizes of all closed shapes are also substantially the same. The partition spacer having a regular pattern may include a honeycomb-shaped partition spacer or a rectangular spacer. The honeycomb-shaped partition spacer may have a non-partition area formed by a combination of regular hexagons, and the rectangular spacer may have a non-partition area formed by a combination of squares or regular rhombuses. In the case of a random-pattern partition spacer, when observed from a normal direction, the closed shapes partitioned by the partitions may have an irregular shape. In one example, a random pattern bulkhead spacer may be derived from randomizing a regular pattern bulkhead spacer. Randomizing the regular pattern bulkhead spacer may mean randomly moving vertices and / or line segments forming a closed polygonal shape of the regular pattern bulkhead spacer. The randomization may cause the line segments to become curves. In the randomization, a plurality of vertices do not overlap each other, and a plurality of line segments do not break or intersect each other. A random pattern bulkhead spacer derived from the randomization of a regular pattern bulkhead spacer may maintain the relationship between the vertices and line segments of the regular pattern. In one example, in the case of a random pattern bulkhead spacer that is a randomization of a honeycomb-shaped regular pattern bulkhead spacer, three curves may meet at one intersection point similar to a honeycomb shape.

[0020] In one example, the barrier rib spacer may be a regular pattern barrier rib spacer. In the case of a regular pattern barrier rib spacer, it may be more advantageous to adjust the alignment 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 alignment direction of the liquid crystal does not affect the polarization direction of the polarizer may mean that the angle formed by the alignment 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, within the range of 0 to 10 degrees or 80 to 90 degrees. This may be advantageous in resolving the light leakage problem caused by the alignment of the liquid crystal on the side of the spacer. However, even in the case of a regular pattern barrier rib spacer, it is sometimes difficult to adjust the angle to the above (for example, in the case of a diamond pattern), and the substrate for an optical device of the present application can resolve the above problem caused by the alignment of the liquid crystal on the side of the spacer.

[0021] In one example, the partition wall spacer may be a randomly patterned partition wall spacer. A randomly patterned partition wall spacer has the advantage of not observing a cross-shaped diffraction pattern when observing a point light source such as sunlight, compared to a regular patterned partition wall spacer. However, in the case of a randomly patterned partition wall spacer, it may not be easy to adjust the alignment direction of the liquid crystals 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 a randomly patterned partition wall spacer, the liquid crystal region in the alignment film on the side of the spacer may affect the polarization direction, increasing the possibility of light leakage. In particular, strong light leakage may occur when the alignment direction of the liquid crystals is at an angle around 45 degrees from the polarization direction. This causes sparkling, and a circular rainbow pattern may be generated by continuous sparkling at similar angles. The substrate for an optical device of the present application can solve the above problem caused by the alignment of the liquid crystals on the side of the spacer.

[0022] The spacer may include a curable resin. The curable resin may be a thermosetting resin or a photocurable resin. The thermosetting resin may include at least one selected from the group consisting of silicone resins, silicon resins, franc resins, polyurethane resins, epoxy resins, amino resins, phenol resins, urea resins, polyester resins, and melamine resins. The photocurable resin may be a UV curable resin. In one example, the photocurable resin may be an acrylic resin. The acrylic resin may refer to an acrylic polymer including polymerization units derived from (meth)acrylic acid ester monomers. The acrylic polymer may include at least one selected from the group consisting of 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 include 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 include a monomer and / or a polymer so as to be capable of including the above-mentioned curable resin through curing.

[0023] In one example, the spacer may further include a black dye. If the spacer further includes a black dye, it may be advantageous in reducing light leakage occurring in the spacer region. The black dye may be an inorganic material such as carbon black or an organic material such as lactam black. The content of the black dye may be appropriately selected within a range that does not impair the purpose of the present application. In one example, the black dye may be included in an amount of 0.1 to 20 parts by weight based on 100 parts by weight of the solid content of the curable resin composition.

[0024] In one example, the spacer may be formed by a patterning process. For example, the spacer may be formed by a photolithography process. The photolithography process may include a process of applying a curable resin composition onto a substrate layer (or onto the electrode layer if an electrode layer is formed on the substrate layer) and then irradiating ultraviolet rays through a pattern mask. The pattern mask may be patterned into ultraviolet-transmitting regions and ultraviolet-blocking regions. The photolithography process may further include a process of washing the ultraviolet-irradiated curable resin composition. The ultraviolet-irradiated region is cured, and the non-ultraviolet-irradiated region remains in a liquid state, so that it can be patterned into a partition shape by removing it through the washing process. Accordingly, the ultraviolet-transmitting region of the pattern mask may correspond to the partition shape, and the ultraviolet-blocking region of the pattern mask may correspond to the shape of the internal region formed by the partition. In the photolithography process, after ultraviolet irradiation, a release treatment may be performed on the pattern mask to easily separate the curable resin composition and the pattern mask, or a release paper may be positioned between the layer of the curable resin composition and the pattern mask.

[0025] In one example, the spacer may be formed by an imprinting process. The imprinting method may be performed by applying a curable resin composition onto a substrate layer (or, if an electrode layer is formed on the substrate layer, onto the electrode layer), and then bringing an imprinting mold into contact with the curable resin composition and then removing the curable resin composition. The imprinting mold may have a pattern capable of transferring a desired barrier rib pattern. Any imprinting mold known in the art may be used as the imprinting mold without limitation, and for example, a soft mold may be used. Any material known in the art may be used as the material for the soft mold, and for example, a flexible adhesive resin or PDMS (polydimethylsiloxane) may be used, but is not limited thereto. In the imprinting method, a curing process for curing the curable resin composition may be additionally performed. The curing process may be performed by applying appropriate energy for curing the curable resin composition, for example, irradiating with heat and / or light. The energy for curing may be, for example, ultraviolet light. The conditions for applying the energy for curing are not particularly limited, as long as they are performed so that the curable resin composition can be appropriately cured. The irradiation of the energy for curing may be performed, for example, before, simultaneously with, or after contacting the imprinting mold with the curable resin composition. In addition, in the imprinting method, a release treatment may be performed on the imprinting mold to easily separate the curable resin composition from the imprinting mold.

[0026] The line width, pitch, thickness, and area of ​​the spacer may be appropriately selected within a range that does not impair the purpose of the present application. For example, the line width of the spacer may be in the range of 10 ㎛ to 500 ㎛ or in the range of 10 ㎛ to 50 ㎛. The line width of the spacer refers to the line width of the partition wall when the partition wall spacer is observed in the normal direction and refers to the line width of the upper surface of the partition wall. The spacing between the spacers may be in the range of 100 ㎛ to 1000 ㎛ or in the range of 200 ㎛ to 500 ㎛. The spacing between the spacers may refer to the maximum distance between any two points in the cross-sectional shape of the non-barrier region when the partition wall spacer is observed in the normal direction. The area ratio of the spacer may be, for example, about 5% or more and 50% or less with respect to 100% of the total area of ​​the substrate layer. The area ratio of the spacer can refer to the ratio of the total area of ​​the barrier rib to the total area of ​​the substrate layer when observing the substrate on which the spacer is formed in the normal direction. When the area of ​​the spacer is within the above range, it can be advantageous in securing excellent electro-optical characteristics while appropriately securing the adhesion between the upper and lower substrates. The thickness of the spacer (height of the barrier rib) can be, for example, within the range of 1 μm to 30 μm or 3 μm to 20 μm.

[0027] 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 an inclined surface) (a2) between the upper surface (a1) and the lower surface (a3). The surface of the alignment film may mean a surface opposite to a surface facing the spacer. The upper surface of the alignment film may be induced by the spacer. Therefore, the height of the upper surface may be higher than the height of the lower surface based on the substrate layer. The difference in height between the upper and lower surfaces of the alignment film is due to the height of the spacer. The upper surface of the alignment film may be formed to correspond to the partition wall of the spacer (the convex portion of the spacer).

[0028] When the alignment film has an inclined surface, light leakage can be suppressed even when the liquid crystal cell is used with a polarizer, thereby improving the problems of sparkling 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. However, by using the substrate for an optical device of the present application, the problem of light leakage can be improved.

[0029] When manufacturing the lower substrate of the liquid crystal cell, after forming a spacer, an alignment film can be formed on the spacer. Accordingly, the alignment film can also be present on the upper surface and side surfaces of the spacer. The inclination of the alignment film can be due to the inclination of the side surfaces of the spacer. Liquid crystals positioned close to the alignment film formed on the side surfaces of the spacer can be aligned vertically along the side surfaces of the alignment film. If the inclination angle of the side surfaces of the alignment film is too large, for example, 90 degrees, the optical axis of the liquid crystals aligned along the side surfaces of the alignment film can become parallel to the substrate layer. In this case, a phase difference occurs due to the liquid crystals, and therefore, when used with a polarizer, light leakage may occur due to a misalignment with the polarization direction. If the inclination angle of the inclination surface of the alignment film is below a predetermined range, the optical axis of the liquid crystals aligned along the side surfaces of the alignment film may not be parallel to the substrate layer but rather inclined. In this case, the phase difference caused by the liquid crystal can be reduced, so when used with a polarizer, the occurrence of light leakage caused by misalignment with the polarization direction can be suppressed.

[0030] The inclination angle (θa) formed by the upper surface (a1) and the inclined surface (a2) of the alignment film (hereinafter referred to as the inclination angle of the alignment film) can be appropriately selected in order to solve the above problem. The inclination angle (θa) of the alignment film can be, for example, 47 degrees or less. Specifically, the inclination angle of the alignment film can be 46 degrees or less or 45 degrees or less. More specifically, the inclination angle of the alignment film can be 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 inclination angle of the alignment film 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.

[0031] The alignment film may be a vertical alignment film or a horizontal alignment film. In the present specification, a “horizontal alignment film” may mean a layer including an alignment material that provides horizontal alignment force to a liquid crystal compound present in an adjacent liquid crystal region. In the present specification, a “vertical alignment film” may mean a layer including an alignment material that provides vertical alignment force to a liquid crystal compound present in an adjacent liquid crystal region. The pretilt angle of the adjacent liquid crystal compound with respect to the vertical alignment film may be in the range of 80 to 90 degrees, 85 to 90 degrees, or about 87 to 90 degrees, and the pretilt angle of the adjacent liquid crystal compound with respect to the horizontal alignment film may be in the range of 0 to 10 degrees, 0 to 5 degrees, or 0 to 3 degrees. Unlike an adhesive layer, the alignment film may not have an adhesive force that adheres the upper substrate to the lower substrate. In one example, the alignment film may have a peeling force close to 0 with respect to the upper substrate in the state of the liquid crystal cell of FIGS. 4 to 6.

[0032] The alignment film may be a rubbing alignment film or a photo-alignment film. The alignment direction of the alignment film may follow the rubbing direction in the case of a rubbing alignment film, and the direction of the irradiated polarized light in the case of a photo-alignment film. This alignment direction can be confirmed by a detection method using an absorption-type linear polarizer. Specifically, the alignment direction can be confirmed by placing an absorption-type linear polarizer on one side of the liquid crystal region while the liquid crystal compound included in the liquid crystal region is horizontally aligned, and measuring the transmittance while rotating the polarizer 360 degrees. In this state, when irradiating light toward the liquid crystal region or the absorption-type linear polarizer side and measuring the luminance (transmittance) from the other side, the transmittance tends to be low when the absorption axis or the transmission axis and the alignment direction of the liquid crystal alignment film are aligned. The alignment direction can be confirmed through a simulation that reflects the refractive index anisotropy of the applied liquid crystal compound. A method for confirming the alignment direction according to the mode of the liquid crystal region is known, and in the present application, the alignment direction of the alignment film can be confirmed using this known method.

[0033] The alignment film is a material known to exhibit alignment ability by rubbing alignment, such as a polyimide compound, a poly(vinyl alcohol) compound, a poly(amic acid) compound, a polystyrene compound, a polyamide compound, and a polyoxyethylene compound, or a polyimide compound, a polyamic acid compound, a polynorbornene compound, a phenylmaleimide copolymer compound, a polyvinylcinnamate compound, a polyazobenzene compound, a polyethyleneimide compound, a polyvinyl alcohol compound, a polyamide compound, a polyethylene compound, a polystylene compound, a polyphenylenephthalamide compound, It may include at least one selected from the group consisting of materials known to be capable of exhibiting orientation ability upon light irradiation, such as polyester compounds, chloromethylated polyimide (CMPI) compounds, polyvinylcinnamate (PVI) compounds, and polymethyl methacrylate compounds, but is not limited thereto.

[0034] 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 mean the opposite surface of the surface of the spacer facing the substrate layer. FIGS. 1 to 3 exemplarily illustrate that there is no lower region between the convex portions (partition walls) of the spacer. However, depending on the process of the spacer, for example, when the spacer is formed by an imprinting process, the lower region between the convex portions of the spacer may be formed by a residual film. When the spacer is formed by a photolithography process, the spacer may be formed without the residual film. Alternatively, if a residual film is required, the residual film may also be formed by a photolithography process. The lower region provides a lower surface of the spacer, and in this case, the surface of the spacer may include an upper surface, a lower surface, and a side surface between the upper surface and the lower surface. The angle (θb) formed by the upper surface (b1) and the side surface (b2) of the spacer (hereinafter, referred to as the inclination angle of the spacer) may be in the range of 30 to 90 degrees. The inclination angle (θb) of the spacer may be, for example, 30 degrees or more, 35 degrees or more, 40 degrees or more, 45 degrees or more, 50 degrees or more, 55 degrees or more, 60 degrees or more, 65 degrees or more, 70 degrees or more, 75 degrees or more, 80 degrees or more, or 85 degrees or less, 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.

[0035] The method for controlling the inclination angle of the spacer is not particularly limited, and any method known in the relevant technical field can be appropriately applied. For example, when forming a spacer using a photolithography process, the UV light irradiated during curing can be controlled. If the UV light is straight, the inclination angle of the spacer can be formed to be high, for example, 80 degrees or more, 85 degrees or more, or close to 90 degrees. If the UV light is diffused, the inclination angle of the spacer can be adjusted to be lower. If the UV light is diffused, the light spreads to the sides, and in this case, the tail can be increased as the light intensity increases, allowing the inclination angle to be reduced. Generally, UV irradiated from a UV lamp is diffused light, and by applying a light guide plate to the side irradiated by the UV lamp to allow the light to propagate straight, it can be converted into straight light. As another example, when forming a spacer using an imprinting process, an imprinting mold having an engraved pattern corresponding to the spacer having the desired inclination angle can be used.

[0036] The substrate for an optical device may further include an undercoating layer (105) that is present between the spacer (103) and the alignment film (104). The surface of the undercoating layer may include an upper surface (c1), a lower surface (c3), and an inclined side surface (hereinafter, referred to as an inclined surface) (c2) between the upper surface (c1) and the lower surface (c3). The surface of the undercoating layer may mean a surface opposite to a surface of the undercoating layer facing the spacer. The angle (hereinafter, referred to as an inclined angle of the undercoating layer) (θc) formed by the upper surface (c1) and the inclined surface (c2) of the undercoating layer may be appropriately selected within a range that can satisfy the inclined angle of the alignment film. The inclined angle (θc) of the undercoating layer may be, for example, in a range of 5 to 60 degrees. The inclination angle of the above undercoating layer can be specifically 5 degrees or more, 10 degrees or more, and 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 inclination angle of the undercoating layer can be adjusted, for example, by controlling the thickness of the undercoating layer coated on the spacer. In one example, if the undercoating layer is coated thickly on the spacer, the tail of the inclination surface (c2) of the undercoating layer can be increased, and thus the inclination angle of the undercoating layer can be reduced.

[0037] The undercoating layer may include a curable resin. The curable resin may be a thermosetting resin or a photocurable resin. The thermosetting resin may include at least one selected from the group consisting of silicone resins, silicon resins, franc resins, polyurethane resins, epoxy resins, amino resins, phenol resins, urea resins, polyester resins, and melamine resins. The photocurable resin may be a UV curable resin. In one example, the photocurable resin may be an acrylic resin. The acrylic resin may refer to an acrylic polymer including polymerization units derived from a (meth)acrylic acid ester monomer. The acrylic polymer may include at least one selected from the group consisting of alkyl acrylate polymers, polyester acrylate polymers, polystyrene acrylate polymers, epoxy acrylate polymers, polyurethane acrylate polymers, polybutadiene acrylate polymers, and silicone acrylate polymers.

[0038] The undercoating layer may include 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 resin composition or the photocurable resin composition may include a monomer and / or a polymer so as to include the above-mentioned curable resin through curing. In one example, the curable resin composition may include a (meth)acrylate compound. The (meth)acrylate compound may be a polyfunctional (meth)acrylate compound having two or more (meth)acrylic groups at its terminal. The (meth)acrylate compound may have two to six, or two to four (meth)acrylic groups. In one example, the curable resin composition may include a difunctional (meth)acrylate, a trifunctional (meth)acrylate, and a tetrafunctional (meth)acrylate compound. In one example, the curable resin composition may further include a thiol compound. The above thiol compound may be a multifunctional thiol compound having two or more thiol groups (-SH) at the terminal. The thiol compound may have two to six, two to four, or four thiol groups (-SH).

[0039] In one example, the undercoating layer may further include a black dye. The undercoating layer including the black dye may be formed by adding the black dye to the curable resin composition. When the undercoating layer further includes the black dye, it may be advantageous in reducing light leakage in the area of ​​the undercoating layer present on the side of the spacer. The black dye may be an inorganic material such as carbon black or an organic material such as lactam black. The content of the black dye may be appropriately selected within a range that does not impair the purpose of the present application. The black dye may be included in an amount of 10 to 50 parts by weight based on 100 parts by weight of the solid content of the curable resin composition.

[0040] The substrate for the optical device may further 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 may be equally applied to the electrode layer.

[0041] The method for adjusting the inclination angle of the alignment layer can be appropriately selected within a range that does not compromise the purpose of the present application. Figures 1 to 3 exemplarily illustrate the structure of a substrate in which the angle of the alignment layer is adjusted using various methods.

[0042] In one example, as shown in FIG. 1, the inclination angle (θa) of the alignment film (104) can be controlled by adjusting the coating thickness (104) of the alignment film. By coating the alignment film thickly, the tail of the alignment film on the inclined surface (a2) of the alignment film can be increased, and thus the inclination angle of the alignment film can be reduced.

[0043] In another example, as shown in FIG. 2, the inclination angle (θa) of the alignment film (104) can be controlled by applying an undercoating layer (105) under the alignment film (104). Applying the undercoating layer can induce an inclination on the side surface (b2) of the spacer (103). If the undercoating layer is coated thickly, the tail of the undercoating layer (c2) on the side surface (b2) of the spacer can be increased, thereby reducing the inclination angle of the undercoating layer. Through this, the inclination angle of the alignment film can also be reduced.

[0044] In another example, as shown in FIG. 3, the inclination angle (θa) of the alignment film (104) can be controlled by forming the side surface (b2) of the spacer (103) so that it has an inclination when forming the spacer (103). The smaller the inclination angle (θb, the angle formed by the upper surface and the side surface of the spacer) of the spacer is formed, the smaller the inclination angle (θa) of the alignment film can be.

[0045] In providing a substrate for an optical device of the present application, any one of the three methods for controlling the inclination angle of the alignment film may be applied, or two methods may be applied, or all three methods may be applied.

[0046] The present application also relates to an optical device comprising the substrate. The optical device may include a liquid crystal cell. FIGS. 4 to 6 exemplarily illustrate liquid crystal cells comprising the substrate for an optical device of the present application. FIG. 4 exemplarily illustrates a liquid crystal cell comprising the substrate for an optical device of FIG. 1 . FIG. 5 exemplarily illustrates a liquid crystal cell comprising the substrate for an optical device of FIG. 2 . FIG. 6 exemplarily illustrates a liquid crystal cell comprising the substrate for an optical device of FIG. 3 .

[0047] The liquid crystal cell may include an upper substrate, a lower substrate, and a liquid crystal layer including a liquid crystal compound between the upper substrate and the lower substrate.

[0048] The upper substrate may include a first substrate layer (301) and an adhesive layer (303). The substrate for the optical device may be used as the lower substrate. The lower substrate may include a second substrate layer (101), a spacer (103), and an alignment film (104). A liquid crystal layer (200) may be present in a region between the upper substrate and the lower substrate. The surface of the alignment film may include an upper surface, a lower surface, and an inclined plane between the upper surface and the lower surface. The inclination angle formed by the upper surface and the inclined plane of the alignment film may satisfy a predetermined range, thereby improving the sparkling phenomenon and the rainbow phenomenon.

[0049] The content of the lower substrate described above may be applied in the same manner as that described in the substrate for the optical device. Accordingly, the content of the substrate layer, electrode layer, spacer, undercoating layer, and alignment film described in the substrate for the optical device may be applied in the same manner to the second substrate layer, second electrode layer, spacer, undercoating layer, and alignment film described in the lower substrate. The content of the substrate layer of the substrate for the optical device may be applied in the same manner as that described in the substrate layer of the substrate for the optical device.

[0050] The adhesive layer may be present on the inner surface of the first substrate layer. In the present specification, the "inner surface" of the component included in the liquid crystal cell may mean the surface facing the liquid crystal region (liquid crystal layer). In the present specification, the "outer surface" of the component included in the liquid crystal cell may mean the opposite surface of the surface facing the liquid crystal region (liquid crystal layer). By using the adhesive layer as described above, adhesive strength can be provided between the upper and lower substrates so that the liquid crystal cells do not separate during the bonding process for supporting the liquid crystal composition between the upper and lower substrates or in subsequent processes. In addition, the adhesive layer may be advantageous in roll-to-roll processability and in preventing the liquid crystal composition from flowing.

[0051] In this specification, the adhesive layer may be, for example, a layer of an adhesive composition. In this specification, the term “layer of an adhesive composition” may mean a layer formed by coating or curing an adhesive composition. The term “curing of an adhesive composition” may mean implementing a crosslinking structure in the adhesive composition through a physical or chemical action or reaction of a component included in the adhesive composition. Curing may be induced, for example, by maintaining at room temperature, applying moisture, applying heat, irradiating with active energy rays, or by performing two or more of the above processes together, and in each case, the type of adhesive composition in which curing is induced may be referred to as, for example, a room temperature curable adhesive composition, a moisture curable adhesive composition, a heat curable adhesive composition, an active energy ray curable adhesive composition, or a hybrid curable adhesive composition.

[0052] The adhesive layer may be optically transparent. The adhesive layer may have an average transmittance for light in the visible light range, for example, light having a wavelength of 380 nm to 780 nm, of at least about 80%, at least 85%, at least 90%, or at least 95%.

[0053] The adhesive layer may be a liquid crystal alignment adhesive layer. The adhesive layer may be, for example, a vertical alignment adhesive layer or a horizontal alignment adhesive layer. In the present specification, a “vertical alignment adhesive” may mean an adhesive that provides vertical alignment force to adjacent liquid crystal compounds and has adhesive strength capable of bonding an upper substrate and a lower substrate at the same time. In the present specification, a “horizontal alignment adhesive” may mean an adhesive that provides horizontal alignment force to adjacent liquid crystal compounds and has adhesive strength capable of bonding an upper substrate and a lower substrate at the same time. The pretilt angle of the adjacent liquid crystal compound for the vertically aligned adhesive may 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 the adjacent liquid crystal compound for the horizontally aligned adhesive may be in the range of 0 degrees to 10 degrees, 0 degrees to 5 degrees, or 0 degrees to 3 degrees. According to one embodiment of the present application, the adhesive layer may be a vertically aligned adhesive layer.

[0054] In this specification, the pretilt angle may refer to the angle formed by the direction of the liquid crystal compound with respect to a plane parallel to the liquid crystal alignment adhesive or alignment film when no voltage is applied. In this specification, the direction of the liquid crystal compound may refer to the optical axis or the slow axis of the liquid crystal region. Alternatively, the direction of the liquid crystal compound may refer to the long axis direction when the liquid crystal compound is in the shape of a rod, and may refer to an axis parallel to the normal direction of the plane of the disc when the liquid crystal compound is in the shape of a disc.

[0055] When the adhesive layer is a vertically oriented adhesive layer, the surface energy of the adhesive layer may be 16 mN / m or less. The lower limit of the surface energy of the vertically oriented adhesive layer may be, for example, 5 mN / m or more. When the adhesive layer is a horizontally oriented adhesive layer, the surface energy of the adhesive layer may be greater than 16 mN / m. The upper limit of the surface energy of the horizontally oriented adhesive layer may be, for example, 50 mN / m or less. The surface energy can be measured using a drop shape analyzer (Drop Shape Analyzer, DSA100 product of KRUSS). Specifically, the process of dropping deionized water, which has a known surface tension, on the surface of the adhesive and calculating the contact angle is repeated five times, and the average of the five contact angle values ​​obtained is calculated. Similarly, the process of dropping diiodomethane, which has a known surface tension, and calculating the contact angle is repeated five times, and the average of the five contact angle values ​​obtained is calculated. After that, the surface energy can be calculated by substituting the value of the surface tension of the solvent (Strom value) using the Owens-Wendt-Rabel-Kaelble method using the average value of the contact angles for deionized water and diiodomethane obtained. The surface energy (γsurface) of the sample can be calculated by considering the dispersion force between non-polar molecules and the interaction force between polar molecules (γsurface = γdispersion + γpolar), and the ratio of the polar term (γpolar) in the surface energy γsurface can be defined as the polarity of the surface.

[0056] The thickness of the adhesive layer may be, for example, in the range of 3 μm to 15 μm. When the thickness of the adhesive layer is within the above range, it can be advantageous in minimizing defects such as pressing or crowding of the adhesive when used in the manufacture of a liquid crystal cell while ensuring adhesion between the upper and lower substrates.

[0057] The adhesive layer may be suitably comprised of various types of adhesives known in the industry as optically clear adhesives (OCAs). These adhesives may differ from optically clear resin (OCR) adhesives, which cure after the objects are bonded, in that they cure before the objects are bonded.

[0058] The above adhesive layer may include a silicone adhesive. In the case of a silicone adhesive, the adhesive composition may include a curable silicone compound as an adhesive resin. An adhesive composition including a curable silicone compound as an adhesive resin may be referred to as a silicone composition. The silicone adhesive may include a cured product of the curable silicone compound as an adhesive resin. When a silicone adhesive is used, it may be suitable for exhibiting vertical alignment force for a liquid crystal due to a difference in surface energy with the liquid crystal, and may also be advantageous in terms of preventing contamination of the liquid crystal. The type of the curable silicone compound is not particularly limited, and for example, a heat-curable silicone compound or an ultraviolet-curable silicone compound may be used.

[0059] In one example, the curable silicone compound may be an addition curable silicone compound.

[0060] Specifically, the addition-curable silicone compound may include, but is not limited to, (1) an organopolysiloxane containing two or more alkenyl groups in the molecule and (2) an organopolysiloxane containing two or more silicon-bonded hydrogen atoms in the molecule. Such a silicone compound can form a cured product through an addition reaction, for example, in the presence of a catalyst described below.

[0061] More specific examples of the above (1) organopolysiloxane that can be used in the present application include a dimethylsiloxane-methylvinylsiloxane copolymer with trimethylsiloxane groups capped at both molecular ends, a methylvinylpolysiloxane with trimethylsiloxane groups capped at both molecular ends, a dimethylsiloxane-methylvinylsiloxane-methylphenylsiloxane copolymer with trimethylsiloxane groups capped at both molecular ends, a dimethylpolysiloxane with dimethylvinylsiloxane groups capped at both molecular ends, a methylvinylpolysiloxane with dimethylvinylsiloxane groups capped at both molecular ends, a dimethylsiloxane-methylvinylsiloxane copolymer with dimethylvinylsiloxane groups capped at both molecular ends, a dimethylsiloxane-methylvinylsiloxane-methylphenylsiloxane copolymer with dimethylvinylsiloxane groups capped at both molecular ends, R 1 2SiO 1 / 2 Siloxane units represented by R 1 2R 2 SiO 1 / 2 Siloxane units represented by SiO 4 / 2 Organopolysiloxane copolymer containing siloxane units represented by R 1 2R 2 SiO 1 / 2 Siloxane units represented by SiO 4 / 2 Organopolysiloxane copolymer containing siloxane units represented by R 1 R 2 SiO 2 / 2 Siloxane units represented by R 1 SiO 3 / 2 Siloxane units, or R, represented by 2 SiO 3 / 2 Organopolysiloxane copolymers containing siloxane units represented by R and mixtures of two or more of the above may be mentioned, but are not limited thereto. In the above, R 1 Inland R 2is a hydrocarbon group other than an alkenyl group, and specifically, it may be an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group or a heptyl group; an aryl group such as a phenyl group, a tolyl group, a xylyl group or a naphthyl group; an aralkyl group such as a benzyl group or a phenentyl group; a halogen-substituted alkyl group such as a chloromethyl group, a 3-chloropropyl group or a 3,3,3-trifluoropropyl group, etc. In addition, in the above, R 2 is an alkenyl group, and specifically, it may be a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, or a heptenyl group.

[0062] More specific examples of the above (2) organopolysiloxane that can be used in the present application include methylhydrogenpolysiloxane having trimethylsiloxane groups capped at both molecular ends, dimethylsiloxane-methylhydrogen copolymer having trimethylsiloxane groups capped at both molecular ends, dimethylsiloxane-methylhydrogensiloxane-methylphenylsiloxane copolymer having trimethylsiloxane groups capped at both molecular ends, dimethylpolysiloxane having dimethylhydrogensiloxane groups capped at both molecular ends, dimethylsiloxane-methylphenylsiloxane copolymer having dimethylhydrogensiloxane groups capped at both molecular ends, methylphenylpolysiloxane having dimethylhydrogensiloxane groups capped at both molecular ends, R 1 3SiO 1 / 2 Siloxane units represented by R 1 2HSiO 1 / 2 Siloxane units represented by SiO 4 / 2 Organopolysiloxane copolymer containing siloxane units represented by R 1 2HSiO 1 / 2 Siloxane units represented by SiO 4 / 2 Organopolysiloxane copolymer containing siloxane units represented by R 1 HSiO 2 / 2 Siloxane units represented by R 1 SiO 3 / 2 Siloxane units represented by or HSiO 3 / 2Organopolysiloxane copolymers containing siloxane units represented by R and mixtures of two or more of the above may be mentioned, but are not limited thereto. In the above, R 1 is a hydrocarbon group other than an alkenyl group, and specifically, it may be an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, or a heptyl group; an aryl group such as a phenyl group, a tolyl group, a xylyl group, or a naphthyl group; an aralkyl group such as a benzyl group or a phenentyl group; a halogen-substituted alkyl group such as a chloromethyl group, a 3-chloropropyl group, or a 3,3,3-trifluoropropyl group, etc.

[0063] Among the properties mentioned in this specification, if the measurement temperature affects the result, the property is a property measured at room temperature unless otherwise specified. The term room temperature refers to the natural temperature that has not been heated or cooled, and is typically a temperature within the range of about 10°C to 30°C, or about 23°C or about 25°C. In addition, unless otherwise specified in this specification, the unit of temperature is ℃. Among the properties mentioned in this specification, if the measurement pressure affects the result, the property is a property measured at atmospheric pressure unless otherwise specified. The term atmospheric pressure refers to the natural pressure that has not been pressurized or cooled, and typically refers to about 1 atm as atmospheric pressure.

[0064] The upper and lower substrates of the liquid crystal cell may be attached by an adhesive layer. Specifically, the adhesive layer of the upper substrate and the spacer of the lower substrate may be attached. If an alignment film is formed on the spacer of the lower substrate, the area of ​​the alignment film corresponding to the spacer may be attached to the adhesive layer of the upper substrate.

[0065] The spacer can maintain a gap between the upper substrate and the lower substrate. A liquid crystal region may exist in a region where the spacer does not exist between the upper substrate and the lower substrate. The spacer is a partition-shaped spacer, and the liquid crystal compound may exist in the region partitioned by the partition (non-partition region). The region where the liquid crystal compound exists may be referred to as a liquid crystal region.

[0066] Liquid crystal compounds can switch their alignment states by applying voltage. Liquid crystal compounds whose alignment direction can be changed by applying an external force can be used. As used herein, the term "external force" refers to any external factor that can affect the behavior of a substance within a liquid crystal region, such as an external voltage. Therefore, a state without an external force can refer to a state without the application of an external voltage, etc.

[0067] The type and properties of the liquid crystal compound may be appropriately selected in consideration of the purpose of the present application. In one example, the liquid crystal compound may be a nematic liquid crystal or a smectic liquid crystal. A nematic liquid crystal may refer to a liquid crystal in which rod-shaped liquid crystal molecules are arranged parallel to the long axis direction without any regularity in position, and a smectic liquid crystal may refer to a liquid crystal in which rod-shaped liquid crystal molecules are arranged regularly to form a layered structure and are arranged parallel to the long axis direction with regularity. According to one embodiment of the present application, the liquid crystal compound may be a nematic liquid crystal compound.

[0068] The nematic liquid crystal compound may be selected to have 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 a phase transition point within the above range, i.e., a phase transition point from the nematic phase to the isotropic phase. In one example, the clearing point or phase transition point may be 160°C or lower, 150°C or lower, or 140°C or lower.

[0069] The liquid crystal compound may be a non-reactive liquid crystal compound. A non-reactive liquid crystal compound may refer to a liquid crystal compound that does not have a polymerizable group. Examples of the polymerizable group include, but are not limited to, an acryloyl group, an acryloyloxy group, a methacryloyl group, a methacryloyloxy group, a carboxyl group, a hydroxyl group, a vinyl group, or an epoxy group, and the like, and may include a known functional group known as a polymerizable group.

[0070] The liquid crystal compound may have a positive or negative dielectric anisotropy. The absolute value of the dielectric anisotropy of the liquid crystal compound may be appropriately selected in consideration of the purpose of the present application. The term “dielectric anisotropy (△ε)” may refer to the difference (ε / -ε⊥) between the horizontal dielectric constant (ε / ) and the vertical dielectric constant (ε⊥) of the liquid crystal. In the present specification, the term horizontal dielectric constant (ε / ) refers to a dielectric constant value measured along the direction of the electric field when a voltage is applied such that the direction of the electric field due to the director of the liquid crystal compound and the applied voltage are substantially horizontal, and the term vertical dielectric constant (ε⊥) refers to a dielectric constant value measured along the direction of the electric field when a voltage is applied such that the direction of the electric field due to the director of the liquid crystal compound and the applied voltage are substantially perpendicular. The dielectric anisotropy of the liquid crystal molecule may be in the range of 5 to 25.

[0071] The refractive index anisotropy (△n) of the liquid crystal compound can be appropriately selected considering the purpose of the present application. In this specification, the term "refractive index anisotropy" refers to the extraordinary refractive index (n) of the liquid crystal compound. e ) and the ordinary refractive index (n) o ) difference (n) e -n o ) may mean. The refractive index anisotropy of the liquid crystal compound may be, for example, 0.01 to 0.3. The refractive index anisotropy may be 0.01 or more, 0.05 or more, or 0.07 or more, and may be 0.3 or less, 0.2 or less, 0.15 or less, or 0.13 or less.

[0072] The thickness of the liquid crystal region (liquid crystal layer) can be determined according to the height of the spacer (barrier). The thickness of the liquid crystal region is not particularly limited, and for example, the thickness of the liquid crystal region or the height of the spacer (barrier) can be about 0.01 ㎛ or more, 0.05 ㎛ or more, 0.1 ㎛ or more, 0.5 ㎛ or more, 1 ㎛ or more, 1.5 ㎛ or more, 2 ㎛ or more, 2.5 ㎛ or more, 3 ㎛ or more, 3.5 ㎛ or more, 4 ㎛ or more, 4.5 ㎛ or more, 5 ㎛ or more, 5.5 ㎛ or more, 6 ㎛ or more, 6.5 ㎛ or more, 7 ㎛ or more, 7.5 ㎛ or more, 8 ㎛ or more, 8.5 ㎛ or more, 9 ㎛ or more, or 9.5 ㎛ or more. The upper limit of the thickness of the above liquid crystal region or the height of the spacer (barrier) is not particularly limited, and may generally be about 30㎛ or less, 25㎛ or less, 20㎛ or less, or 15㎛ or less.

[0073] The liquid crystal cell can switch the alignment state of the liquid crystal region according to the applied voltage. In one example, when no voltage is applied to the liquid crystal cell, the liquid crystal region can have a first alignment state, and when voltage is applied to the liquid crystal cell, the liquid crystal region can have a second alignment state different from the first alignment state. Examples of the first alignment state and / or the second alignment state include a horizontal alignment state, a vertical alignment state, a twisted alignment state, an inclined alignment state, a hybrid alignment state, and the like.

[0074] In this specification, the ‘horizontal alignment state’ is a state in which the director of the liquid crystal compound in the liquid crystal region is arranged approximately parallel to the plane of the liquid crystal region, and for example, the angle formed by the director with respect to the plane of the liquid crystal region may be, for example, within a range of about -10 degrees to 10 degrees or about -5 degrees to 5 degrees, or approximately 0 degrees.

[0075] In this specification, the ‘vertical alignment state’ is a state in which the director of the liquid crystal compound in the liquid crystal region is arranged approximately perpendicular to the plane of the liquid crystal region, and for example, the angle formed by the director with respect to the plane of the liquid crystal region may be, for example, within a range of about 80 to 100 degrees or about 85 to 95 degrees, or approximately 90 degrees.

[0076] In this specification, the "twist alignment state" may mean a spiral structure in which the directors of liquid crystal compounds are twisted and aligned along an imaginary spiral axis within a liquid crystal region to form layers. The twist alignment state may be implemented in a vertical, horizontal, or inclined alignment state. That is, the vertical twist alignment mode is a state in which individual liquid crystal compounds are twisted along the spiral axis in a vertically aligned state to form layers, the horizontal twist alignment mode is a state in which individual liquid crystal compounds are twisted along the spiral axis in a horizontally aligned state to form layers, and the inclined twist alignment mode is a state in which individual liquid crystal compounds are twisted along the spiral axis in an inclined aligned state to form layers.

[0077] In this specification, the term “hybrid alignment state” may mean an alignment state in which the tilt angle, which is the angle formed by the direction of the liquid crystal compound within the liquid crystal region with respect to the plane of the liquid crystal region, gradually increases or decreases along the thickness direction of the liquid crystal region.

[0078] In one example, the first alignment state may be a twist alignment state, i.e., the liquid crystal region can be switched between the twist alignment and another alignment state by applying external energy.

[0079] 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 voltage is applied. The twisted alignment state can be a horizontal twisted alignment state.

[0080] In one example, when the liquid crystal compound exists in a vertical alignment state, both a vertical alignment state with respect to the inclined plane of the alignment film and a vertical alignment state with respect to the lower surface of the alignment film can be realized. When the liquid crystal compound is in a vertical alignment state with respect to the inclined plane of the alignment film, it can be in a tilted alignment state with respect to the substrate layer. In this case, by reducing the phase difference caused by the liquid crystal, light leakage due to misalignment with the polarization direction of the polarizer can be suppressed.

[0081] The liquid crystal region may further include a chiral dopant. When the liquid crystal region includes a chiral dopant, a twisted alignment state can be realized. As a chiral dopant that can be included in the liquid crystal region, as long as it is a chiral agent that can induce a desired twisting without damaging liquid crystal properties, for example, nematic regularity, it can be used without particular limitation. The chiral agent for inducing rotation in the liquid crystal compound must have at least chirality in its molecular structure. Examples of the chiral agent include a compound having one or more asymmetric carbons, a compound having an asymmetric point on a heteroatom such as a chiral amine or chiral sulfoxide, or a compound having an axially asymmetric, optically active site with an axial agent such as cumulene or binaphthol. The chiral agent may be, for example, a low-molecular-weight compound having a molecular weight of 1,500 or less. Commercially available chiral nematic liquid crystals, such as the chiral dopant liquid crystal S-811 available from Merck or LC756 available from BASF, may be used as the chiral agent.

[0082] The application ratio of the chiral dopant can be selected so as to achieve the desired pitch (P). In general, the content (weight %) of the chiral dopant can be calculated by the formula 100 / (HTP×P). The HTP represents the helical twisting power of the chiral dopant and the unit is ㎛. -1 It can be. The above P can be the pitch of the liquid crystal in a twisted alignment state, and the unit can be ㎛. The pitch (p) of the liquid crystal region can be measured by a measurement method using a wedge cell, and specifically, it can be measured by 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 by the measurement method using the above-mentioned wedge cell. Alternatively, the HTP value can be typically provided by a supplier of the liquid crystal and the chiral dopant. The content of the chiral dopant can be determined by considering the target pitch with reference to the above method.

[0083] In one example, the pitch (unit: μm) of the liquid crystal in the twist alignment state can be within the range of 15 μm to 50 μm. Specifically, the pitch can be 16 μm or more, 17 μm or more, 18 μm or more, 19 μm or more, or 20 μm or more, and 50 μm or less, 45 μm or less, 40 μm or less, 35 μm or less, or 30 μm or less.

[0084] The liquid crystal region may further include a dichroic dye. The dichroic dye can control the light transmittance tunable characteristic of the liquid crystal region. As used herein, the term "dye" may refer to a material capable of intensively absorbing and / or modifying light within at least a portion or the entire range within the visible light range, for example, a wavelength range of 400 nm to 700 nm, and the term "dichroic dye" may refer to a material capable of anisotropic absorption of light within at least a portion or the entire range within the visible light range.

[0085] A liquid crystal region including a liquid crystal compound and a dichroic dye may be a GHLC layer (Guest host liquid crystal layer). In the present specification, the "GHLC layer (Guest host liquid crystal layer)" may mean a functional layer in which a dichroic dye is arranged together with the arrangement of a liquid crystal compound, and exhibits anisotropic light absorption characteristics with respect to the alignment direction of the dichroic dye and the direction perpendicular to the alignment direction, respectively. For example, a dichroic dye is a material whose light absorption rate varies depending on the polarization direction. If the absorption rate of light polarized in the major axis direction is high, it may be called a p-type dye, and if the absorption rate of light polarized in the minor axis direction is high, it may be called an n-type dye. In one example, when a p-type dye is used, polarized light that vibrates in the major axis direction of the dye is absorbed, and polarized light that vibrates in the minor axis direction of the dye is less absorbed and can be transmitted. Unless otherwise specified, it is assumed that the dichroic dye is a p-type dye.

[0086] As a dichroic dye, a known dye known to have a property of being able to be aligned according to the alignment state of a liquid crystal compound, for example, by the so-called guest-host effect, can be selected and used. Examples of such dichroic dyes include azo dyes, anthraquinone dyes, methine dyes, azomethine dyes, merocyanine dyes, naphthoquinone dyes, tetrazine dyes, phenylene dyes, quterylene dyes, benzothiadiazole dyes, diketopyrrolopyrrole dyes, squaraine dyes, or pyromethene dyes, but the dyes applicable in the present application are not limited thereto.

[0087] A dichroic dye having a dichroic ratio, that is, a value obtained by dividing the absorption of polarized light parallel to the major axis of the dichroic dye by the absorption of polarized light parallel to the direction perpendicular to the major axis, of 5 or more, 6 or more, or 7 or more may be used. The dichroic dye may satisfy the dichroic ratio at at least some wavelengths or any one wavelength within a wavelength range of the visible light region, for example, within a wavelength range of about 380 nm to 700 nm or within a wavelength range of about 400 nm to 700 nm. The upper limit of the dichroic ratio may be, for example, about 20 or less, 18 or less, 16 or less, or 14 or less.

[0088] The content of the dichroic dye within the liquid crystal region may be appropriately selected in consideration of the purpose of the present application. For example, the content of the dichroic dye within the liquid crystal region may be 0.2 wt% or more. Specifically, the content of the dichroic dye may be 0.5 wt% or more, 1 wt% or more, 2 wt% or more, or 3 wt% or more. The upper limit of the content of the dichroic dye may be, for example, 10 wt% or less, 9 wt% or less, 8 wt% or less, 6 wt% or less, or 5 wt% or less. If the content of the dichroic dye within the liquid crystal region is too low, it may be difficult to express the desired transmittance variable characteristics, and if the content of the dichroic dye within the liquid crystal region is too high, there is a risk of precipitation. Therefore, it may be advantageous for the content of the dichroic dye to be within the above range.

[0089] The upper substrate may further include a first electrode layer (302) between the first substrate layer (301) and the adhesive layer (303). The first electrode layer (302) may be in contact with the inner surface of the first substrate layer (301). The adhesive layer (303) may be in contact with 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 (101) and a spacer (103). The second electrode layer (102) may be in contact with the inner surface of the second substrate layer (201). The spacer (103) may be in contact with the inner surface of the second electrode layer (202).

[0090] The first electrode layer and the second electrode layer may perform a function of applying an external action, for example, an electric field, so as to allow a material included in the liquid crystal region to transmit or block incident light. In one example, the first electrode layer and / or the second electrode layer may include, but is not limited to, a conductive polymer, a conductive metal, a conductive nanowire, or a metal oxide such as ITO (Indium Tin Oxide). The first electrode layer and / or the second electrode layer may be formed by depositing, for example, the conductive polymer, the conductive metal, the conductive nanowire, or the metal oxide such as ITO (Indium Tin Oxide).

[0091] In this specification, the combination of the first substrate layer, the first electrode layer, and the adhesive layer may be referred to as the upper substrate, and the combination of the second substrate layer, the second electrode layer, the spacer, and the alignment film may be referred to as the lower substrate. The lower substrate may further include an undercoating layer. In the liquid crystal cell, the upper substrate may not include a separate alignment film other than the adhesive layer, and the lower substrate may include an alignment film. In the liquid crystal cell, the alignment film may be in contact with the liquid crystal layer.

[0092] The optical device may further include a polarizer. In one example, the optical device may further include a first polarizer disposed on an outer side of the upper substrate and a second polarizer disposed on an outer side of the lower substrate. The first polarizer may be attached to an outer surface of the upper substrate, and the second polarizer may be attached to an outer surface of the lower substrate. A known adhesive layer used in the manufacture of an optical device may be applied to attach the substrates and the polarizer.

[0093] Liquid crystal regions may exist on the inner side of each of the upper and lower substrates.

[0094] As used herein, the term polarizer refers to a film, sheet, or device having a polarizing function. A polarizer is a functional device capable of extracting light vibrating in one direction from incident light vibrating in multiple directions.

[0095] The first polarizer and the second polarizer may each be an absorptive polarizer or a reflective polarizer. In the present specification, an absorptive polarizer refers to an element that exhibits selective transmission and absorption characteristics with respect to incident light. The absorptive polarizer may, for example, transmit light vibrating in one direction from incident light vibrating in multiple directions and absorb light vibrating in the remaining directions. In the present specification, a reflective polarizer refers to an element that exhibits selective transmission and reflection characteristics with respect to incident light. The reflective polarizer may, for example, transmit light vibrating in one direction from incident light vibrating in multiple directions and reflect light vibrating in the remaining directions.

[0096] As the above absorption type polarizer, for example, a polarizing layer dyed with iodine on a polymer stretched film such as a PVA (poly(vinyl alcohol)) stretched film, or a guest-host type polarizing layer using a liquid crystal polymerized in an aligned state as a host and a dichroic dye arranged according to the orientation of the liquid crystal as a guest may be used, but is not limited thereto.

[0097] As the above reflective polarizer, for example, a reflective polarizing layer known as a so-called DBEF (Dual Brightness Enhancement Film) or a reflective polarizing layer formed by coating a liquid crystal compound such as LLC (Lyotropic liquid crystal) can be used, but is not limited thereto.

[0098] The polarizer may be a linear polarizer. In the present specification, a linear polarizer means a case where the light that is selectively transmitted is linearly polarized light that vibrates in one direction and the light that is selectively absorbed or reflected is linearly polarized light that vibrates in a direction perpendicular to the vibration direction of the linearly polarized light. In the case of an absorptive linear polarizer, the optical transmission axis and the optical absorption axis may be perpendicular to each other. In the case of a reflective linear polarizer, the optical transmission axis and the optical reflection axis may be perpendicular to each other.

[0099] The transmittance of the first polarizer and the second polarizer for light having a wavelength of 550 nm may each be in the range of 40% to 50%. The transmittance may refer to the single transmittance of the polarizer for light having a wavelength of 550 nm. The single transmittance of the polarizer may be measured, for example, using a spectrometer (V7100, manufactured by Jasco). For example, the single transmittance may be calculated after measuring the transmittance of each while setting air as the base line and aligning the axis of the polarizer sample vertically and horizontally with the axis of the reference polarizer while placing the polarizer sample (excluding the upper and lower protective films) in the device.

[0100] The light transmission axis of the first polarizer and the light transmission axis of the second polarizer may be perpendicular to each other. Specifically, the angle formed by the light transmission axis of the first polarizer and the light transmission axis of the second polarizer may be within a range of 80 to 100 degrees or 85 to 95 degrees, or may be about 90 degrees. When the substrate for an optical device of the present application is used, if the light transmission axis of the first polarizer and the light transmission axis of the second polarizer are perpendicular, it may be effective in suppressing a light leakage phenomenon caused by the misalignment of the alignment direction of the liquid crystal and the polarization direction of the polarizer.

[0101] The above optical device may further include various functional layers as needed. Examples of the functional layers include, but are not limited to, a polarizer protective film, an anti-reflection film, a phase difference film, a hard coating layer, and an anti-fouling layer.

[0102] The optical device may be a variable transmittance device. The variable transmittance device may be capable of switching between at least two states having different transmittances. In one example, the variable transmittance device may be a device capable of switching between a transparent and a blocking mode state.

[0103] The variable transmittance device in the above-described transmission mode state may have a transmittance of at least 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, or 80%. The transmittance in the above-described transmission mode may be, in other examples, 100% or less, 95% or less, 90% or less, or 85% or less. However, since a higher transmittance in the transmission mode is advantageous, the upper limit thereof is not particularly limited.

[0104] In the above blocking mode state, the transmittance of the variable transmittance device may 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. The transmittance in the blocking mode may be 0% or more, 5% or more, 10% or more, 15% or more, 20% or more, or 25% or more in other examples. However, since a lower transmittance is advantageous in the blocking mode, the lower limit of the transmittance in the blocking mode state is not particularly limited.

[0105] The above transmittance may be, for example, a straight-line light transmittance. The straight-line light transmittance is a percentage of the ratio of light transmitted in the same direction as the incident direction with respect to light incident on the device. For example, if the device is in the form of a film or sheet, the percentage of light transmitted through the device in the direction parallel to the normal direction of the film or sheet surface among the light incident in the direction parallel to the normal direction may be defined as the transmittance.

[0106] The above transmittance may be transmittance for any one wavelength within the visible light range, for example, within the range of about 400 to 700 nm or about 380 to 780 nm, transmittance for the entire visible light range, maximum or minimum transmittance among the transmittances for the entire visible light range, or an average value of the transmittances within the visible light range.

[0107] The optical device described above can be used for various purposes, such as sunglasses, eyewear such as eyewear for Augmented Reality (AR) or Virtual Reality (VR), and sunroofs for exterior walls of buildings or vehicles. In one example, the optical device itself can be a sunroof for a vehicle. For example, in a vehicle including a body having at least one opening formed therein, the optical device can be used as a sunroof by being mounted in the opening, or a sunroof including the optical device can be mounted and used.

[0108] The present application relates to a substrate for an optical device. The present application can provide a substrate for an optical device in which the cell gap between the upper substrate and the lower substrate of a liquid crystal cell is appropriately maintained, excellent adhesion between the upper substrate and the lower substrate is provided, and sparkling and rainbow phenomena are improved to provide excellent visibility.

[0109] Fig. 1 illustrates an example of a substrate for an optical device of the present application.

[0110] Fig. 2 illustrates an example of a substrate for an optical device of the present application.

[0111] Fig. 3 illustrates an example of a substrate for an optical device of the present application.

[0112] FIG. 4 illustrates an example of a liquid crystal cell including a substrate for the optical device of FIG. 1.

[0113] FIG. 5 illustrates an example of a liquid crystal cell including a substrate for the optical device of FIG. 2.

[0114] FIG. 6 illustrates an example of a liquid crystal cell including a substrate for the optical device of FIG. 3.

[0115] Figure 7 is an image showing the sparkling and rainbow phenomena observed in examples and comparative examples.

[0116] Fig. 8 illustrates an example substrate for an optical device of a comparative example.

[0117] The present application is specifically described through the following examples, but the scope of the present application is not limited by the following examples.

[0118] Measurement Example 1. Measurement of inclination angle

[0119] The slope angle was measured by cross-sectional analysis using a Field Emission Scanning Electron Microscope (FE-SEM). For FE-SEM cross-sectional analysis, a specimen was prepared by cutting the measurement target to a size of 20 mm × 20 mm (width × length = 20 mm). A cross-sectional analysis of the specimen was performed using FE-SEM, and the analysis conditions were as follows: Accelerating Voltage: 5 kV; Beam Intensity: 10; Magnification: Х5000. From the FE-SEM analysis image, the slope angle was measured only within the area where the slope angle was constant from the top surface of the measurement target.

[0120] Example 1

[0121] Manufacturing of the upper substrate

[0122] An OCA type adhesive resin (KR3700, ShinEtsu) was mixed in a toluene solvent so that the solid concentration was 25 wt%, and 15 parts by weight of a crosslinking agent (Tetrakis(Dimethylsiloxy)Silane, Gelest) and 1 part by weight of a platinum catalyst (CAT-PL-56, ShinEtsu) were added to 100 parts by weight of the adhesive resin to prepare an adhesive composition. The adhesive composition was bar coated on a fluorine release film (FSC6, Nippa) and then heated at a temperature of 140°C for 6 minutes to form an adhesive layer having a final thickness of about 10 μm. The adhesive layer was laminated on an ITO layer of a PET-ITO film to prepare an upper substrate. The above PET-ITO film is a film in which an ITO (Indium Tin Oxide) layer is deposited to a thickness of approximately 30 nm on a highly stretchable PET (polyethyleneterephtalate) film (OCF, SKC), and has a width × length = 300 mm × 300 mm and a total thickness of approximately 145 μm. The manufactured upper substrate has a structure in which PET film / ITO layer / adhesive layer / release film are laminated in that order.

[0123] Manufacturing of the lower substrate

[0124] An acrylic resin composition (KAD-03, Minutatech Co., Ltd.) was coated on the ITO layer of the same PET-ITO film used in the upper substrate, and then a barrier rib spacer having an inclination angle of about 85 degrees was formed by a photolithography method. The barrier rib spacer had a random pattern obtained by randomizing a regular hexagonal pattern (honeycomb pattern) with a gap of about 350 μm between two facing sides. The height of the barrier rib of the barrier rib spacer was about 6 μm, and the line width of the barrier rib (based on the upper surface of the barrier rib) was about 15 μm. Next, a vertical alignment film (5661LB3, Nissan Co., Ltd.) was coated so that the thickness of the lower region between the barrier ribs became about 400 nm, and then rubbed in one direction with a rubbing cloth to manufacture the lower substrate. The thickness of the upper region of the vertical alignment film on the partition spacer (the distance from the upper surface a1 of the vertical alignment film to the upper surface b1 of the spacer) was about 80 nm, and the inclination angle of the vertical alignment film was about 45 degrees.

[0125] Manufacturing of liquid crystal cells

[0126] The fluorine-containing film was peeled off from the upper substrate. A liquid crystal composition was coated on the alignment layer of the lower substrate, and then laminated with the upper substrate to produce 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 (△n) of 0.094 and negative dielectric anisotropy and a chiral dopant (S811, Merck). The produced 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.

[0127] Example 2

[0128] A liquid crystal cell was manufactured in the same manner as in Example 1, except that the lower substrate was manufactured as follows. First, a barrier rib spacer was formed on the ITO layer of a PET-ITO film in the same manner as in Example 1. Next, a vertical alignment film (5661LB3, Nissan) was coated so that the thickness of the lower region between the barrier ribs was about 800 nm, and then rubbed in one direction with a rubbing cloth to manufacture the lower substrate. The thickness of the upper region of the vertical alignment film on the barrier rib spacer was about 150 nm, and the inclination angle of the vertical alignment film was about 15 degrees.

[0129] Example 3

[0130] A liquid crystal cell was manufactured in the same manner as in Example 1, except that the lower substrate was manufactured as follows. First, a barrier rib spacer was formed on the ITO layer of the PET-ITO film in the same manner as in Example 1. Next, an undercoating layer was formed so that the thickness of the lower region between the barrier ribs was about 400 nm. The undercoating layer was coated with a UV-curable acrylic resin composition and then irradiated with UV-A ultraviolet rays at 400 mJ / cm. 2 It was formed by irradiating and curing with UV curable acrylic resin composition. The above UV curable acrylic resin composition contains 8.7 wt% of Tricyclodecane dimethanol diacrylate (MIRAMER M262, MIWON), 2.9 wt% of acrylate mixture (product number: 246794, Sigma-Aldrich), and 2.9 wt% of Pentaerythritol tetrakis(3-mercaptobutylate) (KarenzMT) in solid content. TMThe composition comprises 2.9 wt% of PE1, Resonac and 0.4 wt% of initiator (Irgacure127, BASF) and the remainder of PGME (Propylene Glycol Monomethyl Ether) as a solvent. The acrylate mixture is a mixture of pentaerythritol tetraacrylate, pentaerythritol triacrylate and trimethylolpropane triacrylate. The thickness of the upper region on the barrier rib spacer of the undercoating layer (the distance from the upper surface c1 of the undercoating layer to the upper surface b1 of the spacer) was about 160 nm, and the inclination angle after the formation of the undercoating layer (the inclination angle of the undercoating layer) was about 51 degrees. Subsequently, a vertical alignment film (5661LB3, Nissan) was coated so that the thickness of the lower region between the barrier ribs became about 100 nm, and then rubbed in one direction with a rubbing cloth to manufacture a lower substrate. The thickness of the upper region on the partition spacer of the vertical alignment film was about 20 nm, and the inclination angle of the vertical alignment film was about 41 degrees.

[0131] Example 4

[0132] A liquid crystal cell was manufactured in the same manner as in Example 1, except that the lower substrate was manufactured as follows. First, a barrier rib spacer was formed on the ITO layer of the PET-ITO film in the same manner as in Example 1. Next, an undercoating layer was formed so that the thickness of the lower region between the barrier ribs was about 800 nm. The undercoating layer was coated with a UV-curable acrylic resin composition and then irradiated with UV-A ultraviolet rays at 400 mJ / cm. 2It was formed by irradiating and curing with UV curable acrylic resin composition same as Example 3. The thickness of the upper region on the partition spacer of the undercoating layer was about 300 nm, and the inclination angle (inclination angle of the undercoating layer) after forming the undercoating layer was about 25 degrees. Next, a vertical alignment film (5661LB3, Nissan) was coated so that the thickness of the lower region between the partition walls was about 100 nm, and then rubbing was performed in one direction with a rubbing cloth to manufacture a lower substrate. The thickness of the upper region on the partition spacer of the vertical alignment film was about 20 nm, and the inclination angle of the vertical alignment film was about 13 degrees.

[0133] Example 5

[0134] A liquid crystal cell was manufactured in the same manner as in Example 1, except that the lower substrate was manufactured as follows. First, a barrier rib spacer was formed on the ITO layer of the PET-ITO film in the same manner as in Example 1. Next, an undercoating layer was formed so that the thickness of the lower region between the barrier ribs was about 800 nm. The undercoating layer was coated with a UV-curable acrylic resin composition and then irradiated with UV-A ultraviolet rays at 400 mJ / cm. 2 It was formed by irradiating and curing with UV curable acrylic resin composition same as Example 3. The thickness of the upper region on the partition wall spacer of the undercoating layer was about 300 nm, and the inclination angle (inclination angle of the undercoating layer) after forming the undercoating layer was about 25 degrees. Next, a vertical alignment film (5661LB3, Nissan) was coated so that the thickness of the lower region between the partition walls was about 300 nm, and then rubbing was performed in one direction with a rubbing cloth to manufacture a lower substrate. The thickness of the upper region on the partition wall spacer of the vertical alignment film was about 60 nm, and the inclination angle of the vertical alignment film was about 6 degrees.

[0135] Example 6

[0136] A liquid crystal cell was manufactured in the same manner as in Example 1, except that the lower substrate was manufactured as follows. First, an acrylic resin composition (KAD-03, Minutatech Co., Ltd.) was coated on the ITO layer of the same PET-ITO film used in the upper substrate of Example 1, and then a barrier rib spacer having an inclination angle of about 50 degrees was formed by a photolithography method. The barrier rib spacer had a random pattern by randomizing a regular hexagonal pattern (honeycomb pattern) with a gap of about 350 μm between two facing sides. The height of the barrier rib of the barrier rib spacer was about 6 μm, and the line width of the barrier rib (based on the upper surface of the barrier rib) was about 15 μm. Next, a vertical alignment film (5661LB3, Nissan Co., Ltd.) was coated so that the thickness of the lower region between the barrier ribs became about 100 nm, and then rubbed in one direction with a rubbing cloth, thereby manufacturing the lower substrate. The thickness of the upper region on the partition spacer of the vertical alignment film was about 20 nm, and the inclination angle of the vertical alignment film was about 41 degrees.

[0137] Example 7

[0138] A liquid crystal cell was manufactured in the same manner as in Example 1, except that the lower substrate was manufactured as follows. First, a barrier rib spacer was formed on the ITO layer of the PET-ITO film in the same manner as in Example 1. Next, an undercoating layer was formed so that the thickness of the lower region between the barrier ribs was about 800 nm. The undercoating layer was coated with a UV-curable acrylic resin composition and then irradiated with UV-A ultraviolet rays at 400 mJ / cm. 2 It was formed by irradiating and curing with UV curable acrylic resin composition. The solid content of the UV curable acrylic resin composition is 8.7 wt% of tricyclodecane dimethanol diacrylate (MIRAMER M262, MIWON), 2.9 wt% of acrylate mixture (product number: 246794, Sigma-Aldrich), and 2.9 wt% of pentaerythritol tetrakis(3-mercaptobutylate) (KarenzMT).TM The undercoating layer contained 2.9 wt% of PE1, Resonac, 0.4 wt% of initiator (Irgacure127, BASF), and PGME (Propylene Glycol Monomethyl Ether) as the remaining solvent, and further contained Lactam Black (SML-333, SCK) as a black dye such that the weight ratio of the solid content to the black dye was 9:1. The thickness of the upper region on the barrier rib spacer of the undercoating layer was about 300 nm, and the inclination angle (inclination angle of the undercoating layer) after the formation of the undercoating layer was about 25 degrees. Subsequently, a vertical alignment film (5661LB3, Nissan) was coated so that the thickness of the lower region between the barrier ribs was about 100 nm, and then rubbed in one direction with a rubbing cloth to manufacture a lower substrate. The thickness of the upper region on the partition spacer of the vertical alignment film was about 20 nm, and the inclination angle of the vertical alignment film was about 13 degrees.

[0139] Example 8

[0140] A liquid crystal cell was manufactured in the same manner as in Example 1, except that the lower substrate was manufactured as follows. First, a barrier rib spacer was formed on the ITO layer of the PET-ITO film in the same manner as in Example 1. Next, an undercoating layer was formed so that the thickness of the lower region between the barrier ribs was about 800 nm. The undercoating layer was coated with a UV-curable acrylic resin composition and then irradiated with UV-A ultraviolet rays at 400 mJ / cm. 2 It was formed by irradiating and curing with UV curable acrylic resin composition containing 8.7 wt% of Tricyclodecane dimethanol diacrylate (MIRAMER M262, MIWON), 2.9 wt% of AE47K, and 8.7 wt% of Pentaerythritol tetrakis(3-mercaptobutylate) (KarenzMT) in solid content. TMThe undercoating layer comprises 2.9 wt% of PE1, Resonac, 0.4 wt% of initiator (Irgacure127, BASF), and PGME (Propylene Glycol Monomethyl Ether) as the remaining solvent, and further comprises Lactam Black (SML-333, SCK) as a black dye such that the weight ratio of the solid content to the black dye is about 6:4. The thickness of the upper region on the barrier rib spacer of the undercoating layer was about 300 nm, and the inclination angle (inclination angle of the undercoating layer) after the formation of the undercoating layer was about 25 degrees. Subsequently, a vertical alignment film (5661LB3, Nissan) was coated such that the thickness of the lower region between the barrier ribs was about 100 nm, and then rubbed in one direction with a rubbing cloth to manufacture a lower substrate. The thickness of the upper region on the partition spacer of the vertical alignment film was about 20 nm, and the inclination angle of the vertical alignment film was about 13 degrees.

[0141] Comparative Example 1

[0142] A liquid crystal cell was manufactured in the same manner as in Example 1, except that the lower substrate was manufactured as follows. First, a barrier rib spacer was formed on the ITO layer of a PET-ITO film in the same manner as in Example 1. Next, a vertical alignment film (5661LB3, Nissan) was coated so that the thickness of the lower region between the barrier ribs was about 100 nm, and then rubbed in one direction with a rubbing cloth to manufacture the lower substrate. The thickness of the upper region of the vertical alignment film on the barrier rib spacer was about 20 nm, and the inclination angle of the vertical alignment film was about 68 degrees.

[0143] Comparative Example 2

[0144] A liquid crystal cell was manufactured in the same manner as in Example 1, except that the lower substrate was manufactured as follows. First, a barrier rib spacer was formed on the ITO layer of the PET-ITO film in the same manner as in Example 1. Next, a vertical alignment film (5661LB3, Nissan) was coated so that the thickness of the lower region between the barrier ribs was about 300 nm, and then rubbed in one direction with a rubbing cloth to manufacture the lower substrate. The thickness of the upper region of the vertical alignment film on the barrier rib spacer was about 60 nm, and the inclination angle of the vertical alignment film was about 51 degrees.

[0145] Comparative Example 3

[0146] A liquid crystal cell was manufactured in the same manner as in Example 1, except that the lower substrate was manufactured as follows. First, a barrier rib spacer was formed on the ITO layer of the PET-ITO film in the same manner as in Example 1. Next, an undercoating layer was formed so that the thickness of the lower region between the barrier ribs was about 200 nm. The undercoating layer was coated with a UV-curable acrylic resin composition and then irradiated with UV-A ultraviolet rays at 400 mJ / cm. 2 It was formed by irradiating and curing with UV curable acrylic resin composition. The same as Example 3 was used for the UV curable acrylic resin composition. The thickness of the upper region on the partition wall spacer of the undercoating layer was about 80 nm, and the inclination angle (inclination angle of the undercoating layer) after forming the undercoating layer was about 60 degrees. Next, a vertical alignment film (5661LB3, Nissan) was coated so that the thickness of the lower region between the partition walls was about 100 nm, and then rubbing was performed in one direction with a rubbing cloth to manufacture a lower substrate. The thickness of the upper region of the vertical alignment film on the partition wall spacer was about 20 nm, and the inclination angle of the vertical alignment film was about 49 degrees.

[0147] Evaluation Example 1. Sparkling and Rainbow Evaluation

[0148] An optical device was manufactured by attaching a first polarizer to one side of the liquid crystal cell manufactured in Examples and Comparative Examples and attaching a second polarizer to the other side of the liquid crystal cell. The first polarizer and the second polarizer were each made of an iodine-dyed polyvinyl alcohol-based stretched film. The transmission axes of the first polarizer and the second polarizer were attached so that they formed an angle of approximately 90 degrees. While observing the optical device with respect to sunlight (in the order of sunlight, the optical device, and the observer), it was confirmed whether a sparkling phenomenon and a rainbow phenomenon were observed. The sparkling phenomenon and the rainbow phenomenon can be observed with the naked eye, and Fig. 7 shows images of the sparkling phenomenon and the rainbow phenomenon (A to C: Comparative Examples 1 to 3, D to K: Examples 1 to 8). The sparkling phenomenon and the rainbow phenomenon were observed in Comparative Examples 1 to 3, whereas the sparkling phenomenon and the rainbow phenomenon were not observed in Examples 1 to 8. The rainbow phenomenon was observed as a circular rainbow, while the sparkling phenomenon was observed as a hazy appearance due to glitter. Since sparkling is the primary cause of rainbows, a strong rainbow can be inferred as a strong sparkling effect.

[0149] In the case of Examples 1 to 8, as illustrated in FIGS. 1 to 3, the liquid crystal (20a) on the lower surface (a3) ​​of the alignment film is normally vertically aligned with respect to the substrate layer (101), and the liquid crystal (20b) on the side surface (a2) of the alignment film is inclined due to the inclination angle of the alignment film, so that the polarization direction of the polarizer is not affected, and thus the sparkling and rainbow phenomena are not induced. On the other hand, in the case of Comparative Examples 1 to 3, as illustrated in FIG. 8, both 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, and it appears that the optical axis of the vertically aligned liquid crystal (20b) on the side surface (a2) of the alignment film becomes horizontal with respect to the substrate layer (101), thereby affecting the polarization direction of the polarizer, and thus causing the sparkling and rainbow phenomena.

[0150] [Explanation of symbols]

[0151] 101: substrate layer (second substrate layer), 102: electrode layer (second electrode layer), 103: spacer, 104: alignment film, 105: undercoating layer, a1: upper surface of alignment film, a2: side surface (inclined surface) of alignment film, a3: lower surface of alignment film, b1: upper surface of spacer, b2: side surface (inclined surface) of spacer, c1: upper surface of undercoating layer, c2: side surface (inclined surface) of undercoating layer, c3: lower surface of undercoating layer, θa: inclination angle of alignment film, θb: inclination angle of spacer, θc: inclination angle of undercoating layer, 301: first substrate layer, 302; second electrode layer, 303; adhesive layer, 200: liquid crystal layer

Claims

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

2. A substrate for an optical device, wherein the spacer in the first paragraph is a spacer in the shape of a partition wall.

3. A substrate for an optical device, wherein the surface of the spacer in the first paragraph 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 within a range of 30 to 90 degrees.

4. A substrate for an optical device, wherein the spacer is present between the substrate layer and the alignment film in the first paragraph.

5. A substrate for an optical device, further comprising an undercoating layer present between the spacer and the alignment film in the first paragraph.

6. In the fifth paragraph, a substrate for an optical device, wherein the undercoating layer comprises a cured product of a curable resin.

7. A substrate for an optical device in accordance with claim 5, wherein the surface of the undercoating layer 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 undercoating layer and the inclined surface is within a range of 5 to 60 degrees.

8. An optical device comprising an upper substrate including a first substrate layer and an adhesive layer; a lower substrate including a second substrate layer, a spacer, 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 an inclined angle formed by the upper surface and the side surface of the alignment film is 47 degrees or less; and a liquid crystal cell including a liquid crystal compound present between the upper substrate and the lower substrate.

9. An optical device in which, in paragraph 8, the spacer is a partition-shaped spacer, and the liquid crystal compound exists in a region partitioned by the partition.

10. An optical device in which, in the 8th paragraph, when the liquid crystal compound exists in a vertical alignment state, both a vertical alignment state with respect to the inclined surface of the alignment film and a vertical alignment state with respect to the lower surface of the alignment film are implemented.

11. An optical device according to claim 8, wherein the liquid crystal cell further includes a first electrode layer present between the first substrate layer and the adhesive layer of the upper substrate, and the lower substrate further includes a second electrode layer present between the second substrate layer and the spacer.

12. An optical device according to claim 8, further comprising 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