Method for producing multilayer body, and multilayer body

Abstract

The present invention addresses the problem of providing: a method for producing a multilayer body that has, on one sheet, a plurality of optical members which each have an optically anisotropic layer that contains a liquid crystal compound, and which each have high positional accuracy, wherein the variation of the optical characteristics among the plurality of optical members is small; and a multilayer body. The problem is solved by: forming an alignment film, which has a non-alignment region and a plurality of alignment regions, on a substrate; forming a coating film by applying a composition, which contains a liquid crystal compound having a polymerizable group, to the alignment film; heating the coating film from the substrate side so as to align the liquid crystal compound in the alignment regions; and exposing the coating film to light, thereby forming an optically anisotropic layer that has a non-alignment region of the liquid crystal compound and a plurality of alignment regions in which the liquid crystal compound is aligned. In addition, the problem is solved by: having the substrate have a thermal expansion coefficient of 10 × 10-6 / °C or less and a thickness of 2 mm or less; and having the heating source for the coating film and the substrate separated from each other.

Description

Method for manufacturing laminate and laminate

[0001] The present invention relates to a method for producing a laminate having a plurality of optical members each including an optically anisotropic layer, and to a laminate produced by this method.

[0002] Head-mounted displays (HMDs) such as AR (Augmented Reality) glasses that display virtual images and various types of information superimposed on an actually viewed scene, and VR (Virtual Reality) glasses that display virtual reality, use various optical members with fine patterns formed thereon. There is a strong demand for miniaturization of such HMDs. Therefore, there is also a demand for miniaturization of the optical members mounted in HMDs.

[0003] Since individually fabricating small optical elements is extremely time-consuming and causes problems in terms of production efficiency and cost, a large number of optical elements are fabricated by arranging them on a large substrate, and then the substrate is cut into individual optical elements.

[0004] For example, Patent Document 1 discloses a method for manufacturing a patterned optical film, in which a long patterned optical film having first regions and second regions corresponding to a plurality of optical elements alternately along the width direction, such as a patterned optical film in which a large number of alternating right-eye and left-eye image regions are formed in a stereoscopic image display device, is cut in a direction parallel to the extension direction of the pattern boundaries.

[0005] JP 2014-164000 A

[0006] When multiple optical members are formed on one substrate, various optical members can be produced, such as an optical member having an optically anisotropic layer (liquid crystal layer) using a liquid crystal compound, such as a liquid crystal lens.

[0007] When forming multiple optical elements having optically anisotropic layers using liquid crystal compounds on a single substrate, for example, an alignment film is formed on the substrate, and alignment regions corresponding to the multiple optical elements are formed on the alignment film. Next, a composition containing a liquid crystal compound (liquid crystal composition) is applied to the alignment film, followed by drying and alignment of the liquid crystal compound. Finally, the liquid crystal composition is cured to form an optically anisotropic layer. In other words, an optical sheet having multiple optical elements having optically anisotropic layers using liquid crystal compounds is a laminate of a substrate, an alignment film, and an optically anisotropic layer.

[0008] Here, according to the inventors' investigations, when multiple optical elements having optically anisotropic layers containing liquid crystal compounds are formed on a single substrate, problems such as low positional accuracy of the optical elements and variations in optical properties among the multiple optical elements may arise.

[0009] The object of the present invention is to solve the problems of the conventional technology and to provide a manufacturing method capable of producing a laminate having a plurality of optical elements, each of which includes an optically anisotropic layer containing a liquid crystal compound, in which the positional accuracy of each optical element is high and the variation in the optical properties of the plurality of optical elements is small, and to provide a laminate manufactured by this manufacturing method.

[0010] In order to solve this problem, the present invention has the following configuration: [1] A method for manufacturing an optically anisotropic layer, comprising: Step 1 of forming an alignment film having a non-aligned region and a plurality of patterned alignment regions on a substrate; Step 2 of applying a composition containing a liquid crystal compound having a polymerizable group onto the alignment film to form a coating film; Step 3 of heating the coating film from the substrate side to align the liquid crystal compound in the patterned alignment region; and Step 4 of exposing the coating film to light to form an optically anisotropic layer having a non-aligned region where the liquid crystal compound is not aligned and a plurality of liquid crystal alignment regions where the liquid crystal compound is aligned, wherein the thermal expansion coefficient of the substrate is 10×10 -6 / °C or less, the thickness of the substrate is 2 mm or less, and in step 3, the coating film is heated while the heat source for the coating film is spaced apart from the substrate. [2] The method for producing a laminate according to [1], wherein in step 3, the distance between the heat source for the coating film and the substrate is 0.1 to 1 mm. [3] The method for producing a laminate according to [1] or [2], wherein in step 3, the distance between the heat source for the coating film and the substrate is achieved by a plurality of pins attached to the heat source. [4] The method for producing a laminate according to [3], wherein the plurality of pins are arranged spaced apart from each other and the distance between the pins is 7 to 30 cm. [5] The method for producing a laminate according to any one of [1] to [4], comprising, after step 4, step 5 of peeling the alignment film and the substrate from the optically anisotropic layer, or peeling the substrate from the alignment film. [6] A laminate comprising a substrate, an alignment film having a non-aligned region and a plurality of patterned alignment regions, and an optically anisotropic layer including a non-aligned region in which a liquid crystal compound is not aligned and a plurality of liquid crystal alignment regions in which the liquid crystal compound is aligned, wherein the thermal expansion coefficient of the substrate is 10×10 -6 / °C or less, and the thickness of the substrate is 2 mm or less. [7] The laminate according to [6], wherein the distance between the plurality of liquid crystal alignment domains is 0.5 to 10 mm. [8] The laminate according to [6] or [7], wherein the liquid crystal alignment domains of the optically anisotropic layer have a liquid crystal alignment pattern in which the direction of the optical axis derived from the liquid crystal compound changes while rotating continuously along at least one direction in the plane, and when the length of a 180° rotation of the direction of the optical axis derived from the liquid crystal compound in the plane is defined as one period, the length of the region in the plane is one period of the liquid crystal alignment pattern. [9] The laminate according to any of [6] to [8], wherein the substrate is alkali-free glass and has a thickness of 1.2 mm or less.

[0011] According to the present invention, a laminate having multiple optical elements, each including an optically anisotropic layer containing a liquid crystal compound, can be obtained in which the positional accuracy of each optical element is high and the variation in the optical properties of the multiple optical elements is small.

[0012] FIG. 1 is a diagram conceptually showing an example of a laminate of the present invention. FIG. 2 is a side view conceptually showing an example of a liquid crystal alignment pattern in an optically anisotropic layer. FIG. 3 is a plan view conceptually showing an example of a liquid crystal alignment pattern in an optically anisotropic layer. FIG. 4 is a conceptual diagram for explaining the function of an optically anisotropic layer. FIG. 5 is a conceptual diagram for explaining the function of an optically anisotropic layer. FIG. 6 is a plan view conceptually showing another example of a liquid crystal alignment pattern in an optically anisotropic layer. FIG. 7 is a conceptual diagram for explaining a method for producing a laminate of the present invention. FIG. 8 is a conceptual diagram of an exposure apparatus for an alignment film. FIG. 9 is a conceptual diagram for explaining a method for producing a laminate of the present invention. FIG. 10 is a conceptual diagram for explaining an example of the present invention.

[0013] The laminate manufacturing method and laminate of the present invention will be described in detail below based on preferred embodiments shown in the accompanying drawings. Note that the drawings shown below are conceptual diagrams for explaining the present invention, and the shape, size, and positional relationship of each component may differ from the actual ones. Furthermore, in the present invention, a numerical range expressed using "to" means a range that includes the numerical values ​​written before and after "to" as the lower and upper limits. Furthermore, in the present invention, "same" and "equal" include a range of error generally accepted in the technical field.

[0014] FIG. 1 conceptually illustrates an example of a laminate of the present invention produced by the laminate production method of the present invention. In FIG. 1, the upper part is a plan view, and the lower part is a side cross-sectional view. In the side cross-sectional view, hatching has been omitted to simplify the drawing. As shown in FIG. 1, a laminate 10 of the present invention includes a substrate 12, an alignment film 14 formed on one surface of the substrate 12, and an optically anisotropic layer 16 formed on the surface of the alignment film 14. The plan view is a view of the laminate 10 from the optically anisotropic layer 16 side in the thickness direction, i.e., a view of the laminate 10 from the optically anisotropic layer 16 side in the stacking direction of the substrate 12, the alignment film 14, and the optically anisotropic layer 16. The side cross-sectional view is a cross-sectional view of the laminate 10 cut in the thickness direction.

[0015] The laminate 10 of the present invention is formed by forming a plurality of optical members (optical elements) on a single sheet-like material (film, plate-like material). In the illustrated example, a total of 30 square optical members 20 are formed on a single laminate 10, arranged at equal intervals in two orthogonal directions, with a 5×6 matrix in the drawing. Therefore, in the alignment film 14, the portion where the optical members 20 are formed is the pattern alignment region of the present invention, and the other region is the non-alignment region of the present invention. Furthermore, in the optically anisotropic layer 16, the region where the optical members 20 are formed is the liquid crystal alignment region of the present invention, and the other region is the non-alignment region of the present invention.

[0016] In the laminate of the present invention, the substrate 12 has a thermal expansion coefficient of 10×10 -6 / °C or less and a thickness of 2 mm or less. This point will be described in detail later.

[0017] In the laminate 10 of the present invention, various known sheet-like materials can be used as the substrate 12 as long as they satisfy the above conditions. Examples of the substrate include substrates made of glass, triacetyl cellulose (TAC), polyethylene terephthalate (PET), polycarbonate, polyvinyl chloride, acrylic, polyolefin, etc. Among these, glass is a preferred example, and alkali-free glass is a more preferred example.

[0018] An alignment film 14 is formed on the surface of the substrate 12. The alignment film 14 is an alignment film for orienting a liquid crystal compound into a predetermined liquid crystal alignment pattern when forming the optically anisotropic layer 16. As described above, in the laminate 10 of the present invention, the alignment film 14 has a plurality of pattern alignment regions corresponding to the optical elements 20 arranged at equal intervals in two orthogonal directions, and non-alignment regions which are the remaining regions. In the alignment film 14, the pattern alignment regions are regions in which an alignment pattern corresponding to the liquid crystal alignment pattern in the liquid crystal alignment regions corresponding to the optical elements 20 in the optically anisotropic layer 16 is formed. On the other hand, in the alignment film 14, the non-alignment regions are regions which do not have such an alignment pattern.

[0019] The orientation pattern in the pattern orientation region, i.e., the liquid crystal orientation pattern in the liquid crystal orientation region of the optically anisotropic layer described later, is not limited, and various known liquid crystal orientation patterns corresponding to the optical element 20, such as a liquid crystal diffraction element, a liquid crystal lens (a converging / diverging type liquid crystal diffraction element), a light diffusion plate (diffuser), a hologram element, a wavelength conversion plate, and an optical filter, can be used. Among these, a liquid crystal orientation pattern in which the orientation of the optical axis derived from the liquid crystal compound changes while continuously rotating along one direction in the plane is a preferred example. Among these, a liquid crystal orientation pattern having this liquid crystal orientation pattern in the form of concentric circles extending from the inside to the outside is a more preferred example (see FIG. 6). Furthermore, in the present invention, when the length of the rotation of the optical axis derived from the liquid crystal compound by 180° in the plane is defined as one period, it is preferable that the liquid crystal orientation pattern has regions in the plane where the length of one period is different.

[0020] The alignment film 14 can be any of various known films used to align liquid crystal compounds, including, for example, a rubbed film made of an organic compound such as a polymer, an obliquely evaporated film of an inorganic compound, a film with microgrooves, and a film formed by accumulating LB (Langmuir-Blodgett) films made by the Langmuir-Blodgett method of organic compounds such as ω-tricosanoic acid, dioctadecylmethylammonium chloride, and methyl stearate.

[0021] The alignment film 14 formed by rubbing treatment can be formed by rubbing the surface of the polymer layer several times in a certain direction with paper or cloth. Preferred materials for the alignment film 14 include polyimide, polyvinyl alcohol, polymers having polymerizable groups as described in JP-A-9-152509, and materials used to form alignment films 14 as described in JP-A-2005-97377, JP-A-2005-99228, and JP-A-2005-128503.

[0022] The alignment film 14 is preferably a so-called photo-alignment film obtained by irradiating a photo-alignable material with polarized or non-polarized light to form the alignment film 14. That is, in the present invention, a photo-alignment film formed by applying a photo-alignment material onto the substrate 12 is preferably used as the alignment film 14. The photo-alignment film can be irradiated with polarized light from a vertical direction or an oblique direction, and the photo-alignment film can be irradiated with non-polarized light from an oblique direction.

[0023] In the present invention, examples of the photo-alignment material used for the alignment film include those disclosed in JP-A Nos. 2006-285197, 2007-76839, 2007-138138, 2007-94071, 2007-121721, 2007-140465, 2007-156439, and 2007-1 azo compounds described in JP-A-133184, JP-A-2009-109831, Japanese Patent Nos. 3,883,848 and 4,151,746; aromatic ester compounds described in JP-A-2002-229039; maleimides having photo-orientable units described in JP-A-2002-265541 and JP-A-2002-317013; / or alkenyl-substituted nadimide compounds, photocrosslinkable silane derivatives described in Japanese Patent Nos. 4205195 and 4205198, photocrosslinkable polyimides, photocrosslinkable polyamides and photocrosslinkable polyesters described in JP-T-2003-520878, JP-T-2004-529220 and JP-T-4162850, and photodimerizable compounds described in JP-A-9-118717, JP-A-10-506420, JP-A-2003-505561, WO 2010 / 150748, JP-A-2013-177561 and JP-A-2014-12823, particularly cinnamate compounds, chalcone compounds and coumarin compounds are exemplified as preferred examples. Among these, azo compounds, photocrosslinkable polyimides, photocrosslinkable polyamides, photocrosslinkable polyesters, cinnamate compounds, and chalcone compounds are preferably used.

[0024] There is no limitation on the thickness of the alignment film 14, and it may be set appropriately to a thickness that provides the necessary alignment function depending on the material forming the alignment film 14. The thickness of the alignment film 14 is preferably 2 nm to 5 μm, more preferably 5 nm to 2 μm, even more preferably 10 nm to 1 μm, and particularly preferably 30 to 200 nm.

[0025] There are no limitations on the method for forming the alignment film 14, and various known methods can be used depending on the material for forming the alignment film 14. One example is a method in which the alignment film 14 is applied to the surface of the substrate 12 and dried to form an unexposed alignment film, and then the alignment film 14 is subjected to interference exposure to form an alignment pattern, thereby forming the alignment film 14. This will be described in detail later.

[0026] An optically anisotropic layer 16 is formed on the alignment film 14. As described above, in the laminate 10 of the present invention, the optically anisotropic layer 16 has a plurality of liquid crystal alignment regions, in which the liquid crystal compound is aligned according to a predetermined alignment pattern, corresponding to the optical members 20, and non-alignment regions, which are the other regions, in which the liquid crystal compound is not aligned.

[0027] The optically anisotropic layer 16 can be formed by applying a composition containing a rod-shaped or discotic liquid crystal compound having a polymerizable group onto the alignment film 14 to form a coating film, drying the coating film and aligning the liquid crystal compound, and then curing the composition containing the liquid crystal compound. In the following description, the composition containing the liquid crystal compound is also referred to as a liquid crystal composition.

[0028] Rod-shaped liquid crystal compounds include azomethines, azoxy compounds, cyanobiphenyls, cyanophenyl esters, benzoates, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines, phenyldioxanes, tolanes, and alkenylcyclohexylbenzonitriles. Not only low-molecular-weight liquid crystal molecules such as those mentioned above, but also polymeric liquid crystal molecules can be used.

[0029] The orientation of the rod-shaped liquid crystal compound is fixed by polymerization in the optically anisotropic layer 36. Examples of polymerizable rod-shaped liquid crystal compounds that can be used include those described in Makromol. Chem., Vol. 190, p. 2255 (1989), Advanced Materials, Vol. 5, p. 107 (1993), U.S. Patent Nos. 4,683,327, 5,622,648, and 5,770,107, International Publication Nos. 95 / 22586, 95 / 24455, 97 / 00600, 98 / 23580, and 98 / 52905, JP-A Nos. 1-272551, 6-16616, 7-110469, and 11-80081, and Japanese Patent Application No. 2001-64627. Furthermore, as the rod-shaped liquid crystal compound, for example, those described in JP-A-11-513019 and JP-A-2007-279688 can also be preferably used.

[0030] Other polymerizable liquid crystal compounds that can be used include cyclic organopolysiloxane compounds having a cholesteric phase, such as those disclosed in JP-A-57-165480. Furthermore, polymeric liquid crystal compounds that can be used include polymers having mesogenic groups exhibiting liquid crystallinity introduced into the main chain, side chain, or both the main chain and side chain, polymeric cholesteric liquid crystals having cholesteryl groups introduced into the side chain, liquid crystalline polymers such as those disclosed in JP-A-9-133810, and liquid crystalline polymers such as those disclosed in JP-A-11-293252.

[0031] —Discotic Liquid Crystal Compound— As the discotic liquid crystal compound, for example, those described in JP-A Nos. 2007-108732 and 2010-244038 can be preferably used. When a discotic liquid crystal compound is used in the liquid crystal layer, the liquid crystal compound 40 stands up in the thickness direction in the liquid crystal layer, and the optical axis derived from the liquid crystal compound, an axis perpendicular to the disc surface, is defined as the so-called fast axis.

[0032] The liquid crystal composition is preferably used as a liquid when forming the optically anisotropic layer 16. Therefore, the liquid crystal composition may contain a solvent. The solvent is not limited and can be selected appropriately depending on the purpose, but organic solvents are preferred. The organic solvent is not limited and can be selected appropriately depending on the purpose, and examples include ketones, alkyl halides, amides, sulfoxides, heterocyclic compounds, hydrocarbons, esters, and ethers. These may be used alone or in combination of two or more. Among these, ketones are preferred when considering the environmental impact.

[0033] In addition to the liquid crystal compound, the optical composition may contain, as needed, chiral agents (chiral agents), surfactants, leveling agents, alignment control agents, polymerization initiators, crosslinking agents, alignment aids, polymerization inhibitors, antioxidants, ultraviolet absorbers, light stabilizers, colorants, and metal oxide fine particles, etc., as long as the optical performance, etc. is not impaired.

[0034] The amount of the liquid crystal compound added to the liquid crystal composition is preferably 75 to 99.9 mass %, more preferably 80 to 99 mass %, and even more preferably 85 to 90 mass %, based on the solid mass of the liquid crystal composition (mass excluding the solvent).

[0035] As described above, in the laminate 10 of the present invention, there are no limitations on the liquid crystal alignment pattern in the liquid crystal alignment region of the optically anisotropic layer 16. A suitable liquid crystal alignment pattern is one in which the direction of the optical axis derived from the liquid crystal compound changes while continuously rotating toward at least one direction within the plane of the optically anisotropic layer. Figure 2 shows a side view of an optically anisotropic layer having this liquid crystal alignment pattern. Figure 3 shows a plan view of an optically anisotropic layer having this liquid crystal alignment pattern. The side view and plan view are similar to those of Figure 1 described above.

[0036] In the laminate 10 of the present invention, in the non-alignment region, the liquid crystal compound is not aligned, and the optical axes derived from the liquid crystal compound are oriented in random directions within the plane.

[0037] The optically anisotropic layer shown in Figures 2 and 3 has a liquid crystal orientation pattern in which the direction of the optical axis 40A derived from the liquid crystal compound 40 changes while continuously rotating in one direction within the plane of the optically anisotropic layer. The optical axis 40A derived from the liquid crystal compound 40 is the axis along which the refractive index of the liquid crystal compound 40 is highest, that is, the so-called slow axis. In Figures 2 and 3, a rod-shaped liquid crystal compound is exemplified as the liquid crystal compound 40. Therefore, in the liquid crystal compound 40, the optical axis 40A is aligned with the long axis direction of the rod shape. As described above, when the liquid crystal compound is a discotic liquid crystal compound, the optical axis is aligned perpendicular to the disc surface.

[0038] As shown in FIG. 3 , on the surface of the alignment film 14, the liquid crystal compound 40 constituting the alignment region of the optically anisotropic layer 16 has a liquid crystal alignment pattern in which the orientation of the optic axis 40A changes while continuously rotating along a predetermined direction indicated by arrow D (hereinafter referred to as alignment axis D) within the plane of the alignment region of the optically anisotropic layer 16, in accordance with the orientation pattern formed on the underlying alignment film 14. In the illustrated example, the liquid crystal alignment pattern is such that the optic axis 40A of the liquid crystal compound 40 changes while continuously rotating clockwise along the alignment axis D. The liquid crystal compound 40 constituting the alignment region of the optically anisotropic layer 16 is two-dimensionally aligned along the alignment axis D and a direction perpendicular to this direction (the alignment axis D direction). In the following description, the direction perpendicular to the alignment axis D direction will be referred to as the Y direction for convenience. That is, the arrow Y direction is the direction perpendicular to the direction in which the orientation of the optic axis 40A of the liquid crystal compound 40 changes while continuously rotating within the plane of the alignment region of the optically anisotropic layer 16. 4 and 5, the Y direction is perpendicular to the paper surface.

[0039] The expression "the orientation of the optical axis 40A of the liquid crystal compound 40 changes while continuously rotating in the direction of the alignment axis D (a predetermined direction)" specifically means that the angle formed between the optical axis 40A of the liquid crystal compound 40 aligned along the alignment axis D and the alignment axis D direction varies depending on the position in the alignment axis D direction, and the angle formed between the optical axis 40A and the alignment axis D direction sequentially changes from θ to θ+180° or θ−180° along the alignment axis D direction. The difference in angle between the optical axes 40A of the liquid crystal compound 40 adjacent to each other in the alignment axis D direction is preferably 45° or less, more preferably 15° or less, and even more preferably a smaller angle.

[0040] In the alignment region of the optically anisotropic layer 16 shown in FIGS. 2 and 3, the optical axis 40A of the liquid crystal compound 40 rotates rightward (clockwise) along the direction of the arrow of the alignment axis D.

[0041] On the other hand, the liquid crystal compound 40 forming the alignment region of the optically anisotropic layer 16 has the same orientation of the optical axis 40A in the Y direction perpendicular to the alignment axis D, i.e., the Y direction perpendicular to the direction in which the optical axis 40A changes while continuously rotating. In other words, the liquid crystal compound 40 forming the alignment region of the optically anisotropic layer 16 has the same angle between the optical axis 40A of the liquid crystal compound 40 and the alignment axis D in the Y direction.

[0042] In the alignment region of the optically anisotropic layer 16, the liquid crystal compounds aligned in the Y direction have the same angle between their optical axes 40A and the alignment axis D. The alignment axis D is a direction in which the orientation of the optical axes of the liquid crystal compounds 40 changes while continuously rotating. A region R is defined as a region in which the liquid crystal compounds 40 aligned in the Y direction have the same angle between their optical axes 40A and the alignment axis D.

[0043] In this case, the in-plane retardation (Re) value in each region R is preferably half the wavelength, i.e., λ / 2. This in-plane retardation is calculated by the product of the refractive index difference Δn associated with the refractive index anisotropy of region R and the thickness of the liquid crystal layer. Here, the refractive index difference associated with the refractive index anisotropy of region R in the liquid crystal layer is a refractive index difference defined by the difference between the refractive index in the direction of the slow axis in the plane of region R and the refractive index in the direction perpendicular to the slow axis. In other words, the refractive index difference Δn associated with the refractive index anisotropy of region R is equal to the difference between the refractive index of liquid crystal compound 40 in the direction of optical axis 40A and the refractive index of liquid crystal compound 40 in the direction perpendicular to the optical axis 40A in the plane of region R. In other words, the refractive index difference Δn is equal to the refractive index difference of the liquid crystal compound. In the optically anisotropic layer 16 described below, which has a concentric liquid crystal orientation pattern in which the optical axis 40A rotates continuously in one direction, the region formed in a circular ring shape with the same center and in which the optical axis 40A has the same direction corresponds to region R in Figure 3.

[0044] In the alignment region of the optically anisotropic layer 16, in the liquid crystal alignment pattern of the liquid crystal compound 40, the length (length Λ (distance)) over which the optical axis 40A of the liquid crystal compound 40 rotates 180° in the alignment axis D direction, in which the optical axis 40A continuously rotates and changes in the plane, is defined as one period Λ in the liquid crystal alignment pattern. That is, one period Λ is the distance between the centers of two liquid crystal compounds 40 that are at the same angle with respect to the alignment axis D direction, in the alignment axis D direction. Specifically, as shown in FIG. 3 , one period Λ is the distance between the centers of two liquid crystal compounds 40 whose alignment axis D direction and the direction of the optical axis 40A coincide with each other, in the alignment axis D direction. In the liquid crystal alignment pattern of the alignment region of the optically anisotropic layer 16, this one period Λ is repeated in one direction, in the alignment axis D direction, i.e., in which the orientation of the optical axis 40A continuously rotates and changes.

[0045] Such a liquid crystal alignment region of the optically anisotropic layer 16 refracts incident circularly polarized light and converts the polarization direction of the circularly polarized light. The function of the liquid crystal alignment region of the optically anisotropic layer 16 will be explained using the conceptual diagrams shown in Figures 4 and 5. It is assumed that the liquid crystal alignment region of the optically anisotropic layer 16 has a product of the refractive index difference of the liquid crystal compound and the thickness of the optical element of λ / 2. In Figures 4 and 5, only the liquid crystal compound 40 on the surface is shown to show the rotation direction of the optical axis in the liquid crystal alignment pattern of the liquid crystal alignment region of the optically anisotropic layer 16. However, the liquid crystal alignment region of the optically anisotropic layer 16 has alignment regions of stacked optically anisotropic layers 16, as in the example shown in Figure 2.

[0046] As shown in Figure 4, when the product of the refractive index difference between the liquid crystal compounds in the liquid crystal alignment region of the optically anisotropic layer 16 and the thickness of the liquid crystal alignment region of the optically anisotropic layer 16 is λ / 2, left-handed circularly polarized incident light L1 is incident on the liquid crystal alignment region of the optically anisotropic layer 16, and the incident light L1 is given a phase difference of 180° as it passes through the liquid crystal alignment region of the optically anisotropic layer 16, and the transmitted light L2 is converted to right-handed circularly polarized light. Furthermore, because the liquid crystal alignment pattern formed in the liquid crystal alignment region of the optically anisotropic layer 16 is a periodic pattern along the alignment axis D, the transmitted light L2 propagates in a direction different from the direction of propagation of the incident light L1. In this way, the left-handed circularly polarized incident light L1 is converted to right-handed circularly polarized transmitted light L2, which is tilted at a certain angle toward the alignment axis D with respect to the incident direction. In the example shown in Figure 4, the transmitted light L2 is diffracted to propagate in a downward and rightward direction.

[0047] On the other hand, as shown in FIG. 5 , when the product of the refractive index difference between the liquid crystal compounds in the liquid crystal alignment region of the optically anisotropic layer 16 and the thickness of the alignment region of the optically anisotropic layer 16 is λ / 2, when right-handed circularly polarized incident light L4 enters the liquid crystal alignment region of the optically anisotropic layer 16, the incident light L4 is given a phase difference of 180° as it passes through the liquid crystal alignment region of the optically anisotropic layer 16 and is converted into left-handed circularly polarized transmitted light L5. Furthermore, because the liquid crystal alignment pattern formed in the liquid crystal alignment region of the optically anisotropic layer 16 is a periodic pattern in the direction of the alignment axis D, the transmitted light L5 travels in a direction different from the traveling direction of the incident light L4. At this time, the transmitted light L5 travels in a different direction from the transmitted light L2, i.e., in the direction opposite to the direction of the arrow of the alignment axis D with respect to the incident direction. In this way, the incident light L4 is converted into left-handed circularly polarized transmitted light L5 tilted at a certain angle in the direction opposite to the direction of the alignment axis D with respect to the incident direction. In the example shown in FIG. 5 , the transmitted light L5 is diffracted to travel in a downward and leftward direction. That is, the optically anisotropic layer 16 having such a liquid crystal orientation pattern is a liquid crystal diffraction element.

[0048] The liquid crystal alignment regions of the optically anisotropic layer 16 can adjust the angle of refraction of transmitted light L2 and L5 by adjusting the length of one period Λ of the formed liquid crystal alignment pattern. Specifically, the shorter the period Λ of the liquid crystal alignment pattern, the stronger the interference between light passing through adjacent liquid crystal compounds, resulting in greater refraction of transmitted light L2 and L5. Therefore, by having regions with different periods Λ in the plane, the optically anisotropic layer 16 can be used as a variety of optical components by adjusting the direction of refraction (diffraction) of light. For example, by gradually shortening the period Λ toward the direction of the alignment axis D, an optical component can be obtained that diverges incident light so as to diverge left-handed circularly polarized light and focus right-handed circularly polarized light.

[0049] Furthermore, by reversing the direction of rotation of the optical axis 40A of the liquid crystal compound, which rotates along the alignment axis D, the direction of refraction of transmitted light can be reversed. That is, in the examples shown in FIGS. 2 to 5 , the rotation direction of the optical axis 40A pointing toward the alignment axis D is clockwise, but by changing this rotation direction to counterclockwise, the direction of refraction of transmitted light can be reversed. Specifically, in FIGS. 4 and 5 , when the rotation direction of the optical axis 40A pointing toward the alignment axis D is counterclockwise, left-handed circularly polarized light entering the liquid crystal alignment region of the optically anisotropic layer 16 from above in the figure passes through the liquid crystal alignment region of the optically anisotropic layer 16, and the transmitted light is converted to right-handed circularly polarized light and diffracted to travel in the lower left direction in the figure. Similarly, right-handed circularly polarized light entering the liquid crystal alignment region of the optically anisotropic layer 16 from above in the figure passes through the liquid crystal alignment region of the optically anisotropic layer 16, and the transmitted light is converted to left-handed circularly polarized light and diffracted to travel in the lower right direction in the figure.

[0050] As described above, in the laminate 10 of the present invention, the liquid crystal alignment region of the optically anisotropic layer 16 preferably has a liquid crystal alignment pattern in which the direction of the optical axis derived from this liquid crystal compound 40 changes while continuously rotating in one direction, in a concentric pattern extending from the inside to the outside. In the laminate 10 shown in Fig. 1, the alignment film 14 and the region of the optically anisotropic layer 16 corresponding to the optical member 20 have this concentric liquid crystal alignment pattern. That is, in the laminate 10, the pattern alignment region of the alignment film 14 and the liquid crystal alignment region of the optically anisotropic layer 16 have this concentric liquid crystal alignment pattern.

[0051] 6 conceptually shows the liquid crystal alignment region of the optically anisotropic layer 16 having this concentric liquid crystal alignment pattern, i.e., a plan view of the optical member 20 in which the optically anisotropic layer 16 has this liquid crystal alignment pattern. In the liquid crystal alignment region of the optically anisotropic layer 16, the alignment of the liquid crystal compound 40 follows the alignment pattern formed in the pattern alignment region of the alignment film 14. Therefore, a similar alignment pattern is also formed in the pattern alignment region of the alignment film 14.

[0052] The liquid crystal alignment region of the optically anisotropic layer 16 shown in Figure 6, i.e., the region corresponding to the optical element 20, has a liquid crystal alignment pattern in which the orientation of the optical axis derived from the liquid crystal compound 40 changes while continuously rotating in one direction, in a concentric pattern extending from the inside to the outside. That is, the liquid crystal alignment pattern of the liquid crystal alignment region of the optically anisotropic layer 16 shown in Figure 6 has a liquid crystal alignment pattern in which the orientation of the optical axis derived from the liquid crystal compound 40 changes while continuously rotating in one direction, in a radial pattern extending from the inside to the outside. Note that, as before, Figure 6 illustrates a rod-shaped liquid crystal compound as the liquid crystal compound 40. Therefore, the direction of the optical axis of the liquid crystal compound 40 coincides with the longitudinal direction of the liquid crystal compound 40, as described above.

[0053] Specifically, in the liquid crystal alignment region of the optically anisotropic layer 16, the direction of the optical axis of the liquid crystal compound 40 changes while continuously rotating in multiple directions, for example, the direction indicated by arrow D1, the direction indicated by arrow D2, the direction indicated by arrow D3, the direction indicated by arrow D4, etc., extending from the center of the liquid crystal alignment region of the optically anisotropic layer 16 toward the outside. In the liquid crystal alignment region of the optically anisotropic layer 16, the rotation direction of the optical axis of the liquid crystal compound 40 is the same in all directions, i.e., in all directions. In the illustrated example, the rotation direction of the optical axis of the liquid crystal compound 40 is counterclockwise in all directions indicated by arrow D1, the direction indicated by arrow D2, the direction indicated by arrow D3, and the direction indicated by arrow D4. In other words, if arrows D1 and D4 are considered to be a single line, the rotation direction of the optical axis of the liquid crystal compound 40 is reversed on this line at the center of the liquid crystal alignment region of the optically anisotropic layer 16. As an example, let us assume that the line formed by the arrows D1 and D4 points to the right in the figure (the direction of the arrow D1). In this case, the optical axis of the liquid crystal compound 40 first rotates clockwise from the outside toward the center of the liquid crystal alignment region of the optically anisotropic layer 16, then reverses its direction at the center of the liquid crystal alignment region of the optically anisotropic layer 16, and then rotates counterclockwise from the center toward the outside of the liquid crystal alignment region of the optically anisotropic layer 16.

[0054] The liquid crystal alignment region of the optically anisotropic layer 16 has a liquid crystal alignment pattern in which one period Λ gradually becomes shorter from the inside to the outside of the concentric circles.

[0055] In the liquid crystal alignment region of the optically anisotropic layer 16 having a concentric liquid crystal alignment pattern as shown in Figure 6, the direction of arrows D1, D2... pointing from the center outward corresponds to the alignment axis D in Figure 5 etc., and each of the concentric circles corresponds to the direction of arrow Y (region R) in Figure 5 etc. Therefore, in the liquid crystal alignment region of the optically anisotropic layer 16 having a concentric liquid crystal alignment pattern, the longitudinal direction of the liquid crystal compound 40, i.e., the direction of the optical axis, is the same in each of the concentric circles. The liquid crystal alignment region of the optically anisotropic layer 16 having a concentric liquid crystal alignment pattern as shown in Figure 6 also diffracts incident light, similar to the optically anisotropic layer having a liquid crystal alignment pattern in which the optical axis changes while rotating in one direction as described above with respect to the direction of arrow D.

[0056] Therefore, the liquid crystal alignment region of the optically anisotropic layer 16 having a concentric liquid crystal alignment pattern as shown in FIG. 6 diffracts incident light toward the center of the concentric circle or diffracts incident light outward from the center of the concentric circle. Here, as described above, the liquid crystal alignment pattern of the liquid crystal alignment region of the optically anisotropic layer 16 has a period Λ that gradually shortens from the inside to the outside of the concentric circle. Therefore, the liquid crystal alignment region of the optically anisotropic layer 16 focuses transmitted light toward the center of the concentric circle or diverges transmitted light from the center to the outside, depending on the rotation direction of the circularly polarized light. That is, the liquid crystal alignment region of the optically anisotropic layer 16 acts like a convex lens that focuses light or a concave lens that diverges light, depending on the rotation direction of the incident circularly polarized light. That is, the optical element 20 is a liquid crystal lens (liquid crystal diffractive lens).

[0057] There is no limitation on the thickness of the optically anisotropic layer, and the thickness that provides the desired optical characteristics may be appropriately set depending on the material forming the optically anisotropic layer, such as the liquid crystal compound.

[0058] Hereinafter, a method for producing the laminate 10 of the present invention will be described with reference to the conceptual diagram of FIG.

[0059] 7, from the top left, the steps of cleaning the substrate 12, forming an unexposed alignment film 14a, exposing the unexposed alignment film to form an alignment film 14, applying a liquid crystal composition to form a coating film, drying and aligning the liquid crystal composition, and curing the liquid crystal composition to form an optically anisotropic layer 16 are carried out to produce the laminate 10 of the present invention. In the example shown in FIG. 7, as a preferred example, after producing the laminate 10, the substrate 12 and the alignment film 14 are peeled off from the optically anisotropic layer 16.

[0060] In the manufacturing method shown in Figure 7, first, the substrate 12 is cleaned, as shown in the upper left side of Figure 7. There are no limitations on the method for cleaning the substrate 12, and various known methods can be used depending on the material and size of the substrate 12. Examples include ultrasonic cleaning, cleaning with a cleaning liquid, cleaning by ultraviolet irradiation, cleaning with a brush, and cleaning using the collision force of two-fluid liquid. A combination of these cleaning methods may be used.

[0061] Next, after drying the washed substrate 12, a composition to become the alignment film 14 is applied to one surface of the substrate 12 and dried to form an unexposed alignment film 14a, as shown in the second from the left in the upper row of Fig. 7. Next, as shown in the third from the left in the upper row of Fig. 7, the unexposed alignment film 14a is exposed to light to form an alignment film 14 having a non-aligned region and a plurality of patterned alignment regions corresponding to the optical member 20 (Step 1).

[0062] As shown in the second from the left in the top row of Figure 7, the unexposed alignment film 14a is formed by applying a composition that will become the alignment film to the surface of the cleaned substrate 12 and drying it. In the example shown in Figure 7, in a preferred embodiment, a composition containing the above-mentioned photo-alignment material is applied to the substrate 12 and dried to form an unexposed photo-alignment film as the unexposed alignment film 14a. There are no limitations on the means 54 for applying the composition that will become the alignment film, and various known means can be used, as with the means 52 for applying the liquid crystal composition described below. The composition can also be dried by a known method appropriate for the composition.

[0063] Next, as shown in the third position from the left in the upper row of Fig. 7, the unexposed alignment film 14a is sequentially exposed at positions corresponding to the optical element 20 to form an alignment film 14 having non-aligned regions and patterned alignment regions. As described above, in this example, the patterned alignment region, i.e., the liquid crystal alignment region of the optically anisotropic layer 16, i.e., the optical element 20, has a liquid crystal alignment pattern in which the orientation of the optical axis derived from the liquid crystal compound 40 changes while continuously rotating in one direction, in a concentric pattern extending from the inside to the outside, as shown in Fig. 6. Fig. 8 conceptually shows an example of an exposure apparatus for forming such a concentric alignment pattern in an alignment film.

[0064] The exposure device 80 shown in Figure 8 has a light source 84 equipped with a laser 82, a polarizing beam splitter 86 that splits laser light M from the laser 82 into S-polarized light MS and P-polarized light MP, a mirror 90A arranged in the optical path of the P-polarized light MP and a mirror 90B arranged in the optical path of the S-polarized light MS, a lens 92 arranged in the optical path of the S-polarized light MS, a beam splitter 94, and a λ / 4 plate 96.

[0065] The P-polarized light MP split by the polarizing beam splitter 86 is reflected by a mirror 90A and enters a beam splitter 94. On the other hand, the S-polarized light MS split by the polarizing beam splitter 86 is reflected by a mirror 90B, collected by a lens 92, and enters the beam splitter 94. The P-polarized light MP and the S-polarized light MS are combined by the beam splitter 94 and converted into right- and left-circularly polarized light according to the polarization direction by a λ / 4 plate 96, and then enter the unexposed alignment film 14a on the substrate 12. Here, the right- and left-circularly polarized light combined by the beam splitter 94 and converted into right- and left-circularly polarized light according to the polarization direction by the λ / 4 plate 96 interfere with each other. Furthermore, one of the circularly polarized light is parallel light, while the other is circularly polarized light collected by the lens 92. Due to the interference between the right- and left-circularly polarized light, the polarization state of the light irradiating the unexposed alignment film 14a changes periodically in the form of interference fringes. Furthermore, in this interference exposure, the crossing angle between the left-handed and right-handed circularly polarized light changes from the inside to the outside of the concentric circles, resulting in an exposure pattern in which one period Λ becomes shorter from the inside to the outside, thereby obtaining a concentric alignment pattern in the unexposed alignment film 14a in which the alignment state changes periodically.

[0066] In this exposure device 80, the length Λ of one period of the liquid crystal orientation pattern, in which the optical axis of the liquid crystal compound 40 changes while continuously rotating 180°, can be controlled by changing the refractive power of the lens 92 (the F-number of the lens 92), the focal length of the lens 92, and the distance between the lens 92 and the unexposed orientation film 14a. Furthermore, by adjusting the refractive power of the lens 92, the length Λ of one period of the liquid crystal orientation pattern can be changed in one direction in which the optical axis changes while continuously rotating. Specifically, the length Λ of one period of the liquid crystal orientation pattern can be changed in one direction in which the optical axis continuously rotates by changing the spread angle of the light expanded by the lens 92, which interferes with the parallel light. More specifically, when the refractive power of the lens 92 is weakened, the light approaches parallel light, so the length Λ of one period of the liquid crystal orientation pattern gradually shortens from the inside to the outside, and the F-number increases. Conversely, when the refractive power of the lens 92 is increased, the length Λ of one period of the liquid crystal alignment pattern suddenly decreases from the inside to the outside, and the F-number decreases.

[0067] When forming a liquid crystal alignment pattern by exposing the unexposed alignment film 14a in this way, it is preferable that the rear surface of the substrate 12, i.e., the surface of the substrate 12 opposite to the unexposed alignment film 14a, has a reflectance of 1% or less of the laser light emitted by the laser 82 of the exposure device 80. In other words, it is preferable that the rear surface of the substrate 12 has a reflectance of 1% or less of the exposure light used to expose the unexposed alignment film 14a to form a pattern alignment region (alignment film).

[0068] When exposing the unexposed alignment film 14a, the exposure light incident on the laminate of the unexposed alignment film 14a and the substrate 12 may be reflected at the interface between the rear surface of the substrate 12 and air and re-enter the unexposed alignment film 14a. Such light may become noise that interferes with proper exposure of the unexposed alignment film 14a, making it impossible to form a properly oriented pattern alignment region (alignment film 14). To prevent such problems, the rear surface of the substrate 12 preferably has a reflectance of 1% or less for the exposure light.

[0069] There are no limitations on the method for reducing the reflectance of the exposure light on the back surface of the substrate 12 to 1% or less, and various known methods suitable for the exposure light can be used. For example, ultraviolet light is often used for exposing a photo-alignment film. In this case, examples of methods for reducing the reflectance of the exposure light on the back surface of the substrate 12 to 1% or less include painting the back surface of the substrate 12 black and providing an anti-reflection film (AR coating) specialized for the ultraviolet wavelength region on the back surface of the substrate 12.

[0070] The laminate 10 shown in FIG. 1 has a total of 30 optical elements 20 arranged in a 5×6 matrix, with five evenly spaced rows and six evenly spaced rows. That is, the alignment film 14 of this laminate 10 has 30 pattern alignment regions arranged in a 5×6 matrix. Correspondingly, in the exposure of the unexposed alignment film 14a, exposure by the exposure device 80 described above and movement of the exposure device 80 are repeated according to the positions of the 30 optical elements 20 arranged in a 5×6 matrix, thereby forming 30 pattern alignment regions corresponding to the optical elements 20. Note that, for simplicity's sake, FIG. 7 shows only the beam splitter 94 of the exposure device 80. This results in an alignment film 14 having 30 pattern alignment regions arranged in a 5×6 matrix and the remaining unexposed non-alignment regions.

[0071] Next, as shown in the upper right of Figure 7, a liquid crystal composition that will become the optically anisotropic layer 16 is applied to form a coating film of the liquid crystal composition (Step 2). As described above, the liquid crystal composition that will become the optically anisotropic layer 16 is preferably a liquid containing a rod-shaped liquid crystal compound or a discotic liquid crystal compound. As described above, surfactants, polymerization initiators, and the like may be added to the liquid crystal composition that will become the optically anisotropic layer 16, as needed. There are no limitations on the liquid crystal composition application means 52, and various known application means (applicators) that can uniformly apply a liquid to a sheet-like material can be used. Examples include printing methods such as inkjet printing and scroll printing, as well as application methods such as die coating, gravure coating, spin coating, bar coating, and spray coating.

[0072] 7, the formed coating film of the liquid crystal composition is heated from the substrate 12 side to dry the coating film of the liquid crystal composition and align the liquid crystal compound in the pattern alignment region of the alignment film 14 (step 3). In the illustrated example, the coating film is heated by a hot plate 30. That is, in the illustrated example, the heating source for the coating film is the hot plate 30.

[0073] In the laminate manufacturing method and laminate of the present invention, the substrate 12 has a thermal expansion coefficient of 10×10 -6 / °C or less, and a thickness of 2 mm or less. Furthermore, in the method for producing a laminate of the present invention, the heating of the coating film of the liquid crystal composition in step 3 is carried out with the heat source and the substrate 12 separated from each other. By having such a configuration, the present invention realizes the production of a laminate comprising a plurality of optical members each having an optically anisotropic layer containing a liquid crystal compound, in which the positional accuracy of the optical members is high and the variation in optical properties of the plurality of optical members is small.

[0074] As shown in Patent Document 1, it is known that the productivity of optical members can be improved and the cost can be reduced by forming a plurality of optical members on a single sheet and finally cutting the sheet into individual optical members. However, according to the studies of the present inventors, when a plurality of optical members are formed on a single sheet in this manner, problems arise, such as low positional accuracy of the optical members and variations in optical properties among the plurality of optical members, in optical members having an optically anisotropic layer containing a liquid crystal compound.

[0075] As a result of investigations, the present inventors have found that the above-mentioned problems are caused by temperature unevenness in the liquid crystal composition coating film, which occurs when the liquid crystal composition coating film is dried and heated to align the liquid crystal compound. That is, in order to form an optically anisotropic layer containing a liquid crystal compound, the liquid crystal composition coating film must be heated to align the liquid crystal compound in the optically anisotropic layer. During this heating, temperature unevenness occurs in the liquid crystal composition coating film, which results in a decrease in the positional accuracy of optical components and variations in the properties of multiple optical components.

[0076] Specifically, if temperature unevenness occurs in the coating film of the liquid crystal composition that will become the optically anisotropic layer 16, the thermal expansion of the coating film (substrate 12) will differ depending on the position in the plane direction, and the positional relationship of the optical element 20 (liquid crystal alignment region) will fluctuate in response to the temperature unevenness. As a result, the positional accuracy of the optical element 20 in the laminate will decrease. Furthermore, if temperature unevenness occurs in the coating film of the liquid crystal composition that will become the optically anisotropic layer 16, the alignment state of each liquid crystal alignment region in the optically anisotropic layer 16 will differ depending on the temperature unevenness. As a result, variations will occur in the optical properties of multiple optical elements.

[0077] In the following description, the coating film of the liquid crystal composition will also be simply referred to as the “coating film.” Unless otherwise specified, the temperature unevenness of the coating film refers to the temperature unevenness in the surface direction.

[0078] As a result of further investigation, the inventors have found that the major causes of temperature unevenness in the coating film are the thermal expansion coefficient of the substrate 12, the thickness of the substrate 12, and uneven heating due to the heat source.

[0079] That is, if the substrate 12 has a large thermal expansion coefficient, heating causes warping of the substrate 12. When the substrate 12 warps, the distance between the heat source, i.e., the hot plate 30 in the illustrated example, and the substrate 12, i.e., the coating, changes. As a result, temperature unevenness, i.e., temperature distribution, occurs in the coating depending on the state of warping of the substrate 12. Furthermore, if the substrate 12 is thick, temperature unevenness occurs in the substrate 12 along the thickness direction. That is, the temperature of the substrate 12 is higher near the heat source and decreases with increasing distance from the heat source along the thickness direction. When temperature unevenness occurs along the thickness direction of the substrate 12, the amount of thermal expansion in the surface direction differs along the thickness direction. As a result, warping also occurs in the substrate 12, and temperature unevenness occurs in the coating depending on the state of warping of the substrate 12, similar to the thermal expansion coefficient described above. Furthermore, in the illustrated example, the coating is heated from the substrate 12 side by the hot plate 30. Here, the entire heating surface of the hot plate 30 is not necessarily flat, but has irregularities. When the substrate 12 (laminate) is placed on the hot plate 30 and heated, the unevenness causes some portions of the substrate 12 to be in contact with the hot plate 30 and some portions to be out of contact. The distance between the non-contacting portions and the hot plate 30 also varies depending on the unevenness. As a result, even if the temperature of the hot plate 30 is uniform across the entire surface, uneven heating occurs, causing uneven temperatures in the coating film.

[0080] In conventional laminate manufacturing methods, not only do these three causes individually cause temperature unevenness, but the three causes also act synergistically to cause temperature unevenness (temperature distribution) in the coating film. For example, if warping occurs in the substrate 12 due to the thermal expansion coefficient, the warping causes variations in the distance from the heat source, resulting in increased temperature unevenness in the thickness direction of the substrate 12. This temperature unevenness in the thickness direction further causes warping of the substrate 12, thereby increasing temperature unevenness in the coating film. Furthermore, if temperature unevenness occurs in the substrate 12 due to uneven heating of the hot plate 30, the temperature unevenness further increases warping due to the thermal expansion coefficient and thickness of the substrate 12, resulting in even greater temperature unevenness.

[0081] In contrast, in the present invention, the substrate 12 has a thermal expansion coefficient of 10×10 -6 / °C or less, and the thickness is 2 mm or less, and the heating of the coating film in step 3 is carried out with a heat source separated from the substrate 12. By having such a configuration, the present invention makes it possible to obtain a laminate comprising a plurality of optical members, each having an optically anisotropic layer containing a liquid crystal compound, in which the positional precision of each optical member is high and the variation in optical properties of the plurality of optical members is small.

[0082] The thermal expansion coefficient of the substrate 12 is 10×10 -6 If the thermal expansion coefficient of the substrate 12 exceeds 5×10 / °C, the substrate 12 will be significantly warped due to heating, the temperature unevenness of the coating film will become large, the dimensional change will be large in areas where the temperature of the coating film is higher than the average of the surroundings, the drying history will change, the film thickness distribution will deteriorate, and the optical properties will deteriorate. -6 The thermal expansion coefficient of the substrate 12 is preferably as small as possible. -6 / °C or higher.

[0083] The thermal expansion coefficient of the substrate 12 may be measured using a thermomechanical analyzer (TMA), an optical thermal expansion measuring device, or the like. Examples of measuring devices include the TMA / SS6100 (manufactured by Hitachi High-Tech Science Corporation) and the SS6100, and examples of optical thermal expansion measuring devices include the DIL806 and ODP868 (manufactured by TA Instruments). Alternatively, if the thermal expansion coefficient of the forming material is listed in a catalog or the like, that value may be used as the thermal expansion coefficient of the substrate 12.

[0084] If the thickness of the substrate 12 exceeds 2 mm, there will be inconveniences such as significant warping of the substrate 12 due to heating caused by the thickness, large temperature unevenness of the coating film, large dimensional changes in areas where the temperature of the coating film is higher than the average of the surrounding area, changes in the drying history, poor film thickness distribution, and poor optical properties. The thickness of the substrate 12 is preferably 1.1 mm or less. There is no particular lower limit for the thickness of the substrate 12, but considering the strength and stability of the laminate 10, the thickness of the substrate 12 is preferably 0.3 mm or more, and more preferably 0.5 mm or more.

[0085] As described above, the material for forming the substrate 12 is not limited as long as it satisfies the above-mentioned thermal expansion coefficient and thickness requirements, and known sheet-like materials can be used. Among these, glass is a preferred example of the substrate 12, and alkali-free glass is even more preferred. Using glass as the substrate 12 is advantageous in terms of thermal expansion, ease of thickness control, rigidity, and other properties. Rigidity specifically refers to a moderate weight and self-supporting properties. Using alkali-free glass as the substrate 12 is particularly advantageous in terms of fewer defects. Since alkali-free glass, which has fewer defects and is manufactured for semiconductor and display applications, is widely available, these alkali-free glasses can be used as the substrate 12. Furthermore, when using alkali-free glass as the substrate 12, it is preferable to set the thickness to 1.2 mm or less.

[0086] In the present invention, the substrate 12 is separated from the hot plate 30, which is a heat source, and the coating film is heated from the substrate 12 side. That is, in the illustrated example, the coating film is heated from the substrate 12 side by radiant heat from the hot plate 30. As described above, when the substrate 12 is placed on the hot plate 30 (heat source), the unevenness of the hot plate 30 creates contact and non-contact areas between the substrate 12 and the hot plate 30, resulting in temperature unevenness in the coating film. In contrast, by heating the coating film while separating the substrate 12 from the hot plate 30, the heating unevenness caused by the contact and non-contact areas between the substrate 12 and the hot plate 30 is prevented, and uniform heating of the substrate 12, i.e., the coating film, is possible.

[0087] In the manufacturing method of the present invention, there is no limitation on the distance between the substrate 12 and the heat source, as long as they are completely separated from each other. Here, the distance between the substrate 12 and the heat source is preferably 0.1 to 1 mm. A distance of 0.1 mm or more between the substrate 12 and the heat source is preferable in that it can effectively prevent contact between the substrate 12 and the heat source and the air layer acts as a buffer to suppress temperature unevenness of the hot plate itself. A distance of 1 mm or less between the substrate 12 and the heat source is preferable in that it can efficiently heat the substrate 12 with the heat source and can increase the temperature rise rate of the coating film. The distance between the substrate 12 and the heat source is more preferably 0.1 to 0.8 mm, even more preferably 0.2 to 0.6 mm, and particularly preferably 0.3 to 0.4 mm.

[0088] There are no limitations on the method for separating the substrate 12 from the heat source when heating the coating film, and various known methods can be used depending on the heat source. When heating is performed using a hot plate 30 as shown in Fig. 7, a method is preferably used in which a plurality of pins 32 are erected on the hot plate 30 and the substrate 12 is placed on the pins 32 to separate the substrate 12 from the hot plate 30, as conceptually shown in Fig. 9.

[0089] There are no restrictions on the distance (spacing) between the pins 32, and the distance can be set appropriately depending on the rigidity of the substrate 12, so that the substrate 12 and the hot plate 30 do not come into contact due to sagging caused by the weight of the laminate. Here, the distance between the pins 32 is preferably 7 to 30 cm. Setting the distance between the pins 32 to 7 cm or more is preferable in terms of preventing a decrease in the heating efficiency of the hot plate 30 caused by an excessive number of pins 32 and improving the efficiency of removing glass sheets. Setting the distance between the pins 32 to 30 cm or less is preferable in terms of effectively preventing sagging of the laminate due to its weight, maintaining a uniform distance between the substrate 12 and the hot plate 30, and maintaining a uniform temperature distribution on the surface of the substrate 12. The distance between the pins 32 is more preferably 7 to 15 cm, and even more preferably 8 to 12 cm.

[0090] There are no particular limitations on the shape of the pins 32 used to separate the substrate 12 from the hot plate 30. Therefore, the shape of the pins 32 is not limited to the pyramidal shapes (pyramidal and conical) shown in the illustrated example. However, a pyramidal or conical shape such as the illustrated example is preferred for the pins 32, as it allows the pins 32 to be stably placed on the hot plate 30 and reduces the contact area between the pins 32 and the substrate 12. Furthermore, it is more preferred that the tip shape of the pins be spherical (curved) to prevent scratches.

[0091] In addition, for example, an infrared lamp or the like can also be used as a heat source. However, with an infrared lamp, the temperature is high near the optical axis and decreases with increasing distance from the optical axis. Therefore, uneven temperature occurs in the heating by the heat source, which in turn causes uneven temperature in the coating film. In addition, hot air can also be used as a heat source, but it is difficult to uniformly heat the entire surface of the substrate 12, i.e., the coating film, using hot air. Considering this point, it is preferable to use a planar heat source such as a hot plate 30 to heat the coating film, as this allows uniform heating of the entire surface of the substrate 12, i.e., the coating film.

[0092] Furthermore, as described above, in the production method of the present invention, the coating film of the liquid crystal composition is heated from the side of the substrate 12. This more suitably reduces temperature unevenness in the coating film of the liquid crystal composition and also prevents foreign matter from adhering to the coating film of the liquid crystal composition due to the heating source located above.

[0093] After the coating film has been dried and the liquid crystal compound has been oriented in this manner, the coating film is irradiated with light from a light source 50 to harden the coating film, i.e., the liquid crystal composition, as shown in the second from the left in the lower part of Figure 7. This forms an optically anisotropic layer 16 having non-oriented regions in which the liquid crystal compound is not oriented and liquid crystal oriented regions in which the liquid crystal compound is oriented (step 4). This completes a laminate 10 having a total of 30 optical elements 20 arranged at equal intervals in a 5x6 matrix, as shown in Figure 1. As described above, the optical elements 20, i.e., the liquid crystal oriented regions of the optically anisotropic layer 16, are liquid crystal lenses having a liquid crystal orientation pattern in which the orientation of the optical axis derived from the liquid crystal compound 40 changes while continuously rotating in one direction, concentrically from the inside to the outside. That is, the illustrated laminate 10 is a laminate having 30 liquid crystal lenses formed therein.

[0094] There are no limitations on the light source 50 used to cure the coating film, and a light source capable of emitting light with a wavelength capable of curing (polymerizing) the liquid crystal composition (liquid crystal compound) may be appropriately selected depending on the liquid crystal composition. Generally, liquid crystal compounds having a polymerizable group are polymerized by irradiation with ultraviolet light. Therefore, an ultraviolet light source is usually used as the light source 50. There are also no limitations on the amount of ultraviolet light irradiation (dose), and the amount of irradiation capable of properly curing the liquid crystal composition may be appropriately set depending on the composition of the liquid crystal composition.

[0095] In the manufacturing method shown in Fig. 7, as a preferred embodiment, the alignment film 14 and the substrate 12 are then peeled from the optically anisotropic layer 16 (step 5), as shown on the right side of the lower part of Fig. 7. In step 5, the substrate 12 may be peeled from the optically anisotropic layer 16 and the alignment film 14. This peeling of the substrate 12 is preferably carried out while the laminate 10 is being transported. The peeled substrate 12 is preferably washed again, as shown on the left side of the upper part of Fig. 7, and reused in the manufacture of the laminate 10.

[0096] There are no limitations on the method for peeling the substrate 12 from the alignment film 14, and various known means can be used, such as a method using an adhesive, a method using a tool such as a scraper that is inserted between the optically anisotropic layer 16 and the alignment film 14 or between the alignment film 14 and the substrate 12 to grip the alignment film 14 and / or the substrate 12, a method of peeling by applying heat due to differences in thermal expansion, and a method of using laser light to trigger peeling.

[0097] The optically anisotropic layer 16 from which the substrate 12 and alignment film 14 have been peeled off is finally cut into individual optical elements 20, i.e., liquid crystal lenses. The cutting position may be determined, for example, based on the boundary between the non-aligned region and the liquid crystal alignment region in the optically anisotropic layer 16. Alternatively, since the optical element 20 is a lens, cutting may be performed based on the optical axis. There are no limitations on the cutting method, and known methods such as punching, a guillotine cutter, or a rotary cutter may be used.

[0098] The method for producing a laminate and the laminate of the present invention have been described above, but the present invention is not limited thereto, and various improvements and modifications may of course be made within the scope of the present invention without departing from the gist of the present invention.

[0099] The features of the present invention will be explained in more detail below with reference to examples. The materials, reagents, amounts used, amounts of substances, ratios, treatment details, and treatment procedures shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

[0100] [Example 1] <Substrate> As a substrate, alkali-free glass having a size of 400 × 350 mm and a thickness of 0.5 mm was prepared. The thermal expansion coefficient of this alkali-free glass was 3 × 10 -6 / ℃.

[0101] <Formation of alignment film> The following coating liquid for forming an alignment film was applied to the surface of the substrate by slit coating. The support on which this coating liquid for forming an alignment film had been formed was dried for 60 seconds on a hot plate at 60°C to form an unexposed alignment film. Coating liquid for forming alignment film ----------------------------------- Photoalignment material A 1.00 parts by mass Water 16.00 parts by mass Butoxyethanol 42.00 parts by mass Propylene glycol monomethyl ether 42.00 parts by mass -----------------------------------

[0102] -Photo alignment material A-

[0103] The alignment film was exposed using the exposure apparatus shown in FIG. 8 to form alignment film P-1. As described above, the exposure apparatus shown in FIG. 8 is an exposure apparatus corresponding to the formation of the liquid crystal alignment pattern shown in FIG. 6, in which the orientation of the optical axis derived from the liquid crystal compound changes while continuously rotating in one direction, and the liquid crystal alignment pattern is arranged in a concentric pattern from the inside to the outside. Furthermore, this liquid crystal alignment pattern has a period that gradually shortens from the center of the concentric circle to the outside. The exposure was performed through a mask with a 40 x 40 mm opening. That is, the size of the pattern alignment region (liquid crystal alignment region), i.e., the optical element, was a rectangle measuring 40 x 40 mm (see FIG. 6). The exposure was performed by moving the substrate so that the spacing between the optical elements (pattern alignment regions) was 2 mm, and the number of optical elements was 8 on the long side of the substrate and 7 on the short side (see FIG. 10).

[0104] <Formation of Optically Anisotropic Layer> A three-layer optically anisotropic layer consisting of first to third optically anisotropic layers was formed. The first and third optically anisotropic layers were tilted optically anisotropic layers in cross-sectional SEM images of the cross sections observed with a scanning electron microscope (SEM), in which the light-dark lines in the cross-sectional SEM images were tilted relative to the normal to the interface. The second optically anisotropic layer disposed between the first and third optically anisotropic layers was a non-tilted optically anisotropic layer in which the light-dark lines in the cross-sectional SEM images coincided with the normal to the interface. The first and third optically anisotropic layers had different tilt directions for the light-dark lines in the cross-sectional SEM images.

[0105] <<Formation of First Optically Anisotropic Layer>> The following composition A-7 was prepared as a liquid crystal composition for forming an optically anisotropic layer.

[0106] Composition A-7 ----------------------------------- Liquid crystal compound L-1 100.00 parts by mass Chiral agent A 0.19 parts by mass Polymerization initiator (Irgacure (registered trademark) 907, manufactured by BASF) 3.00 parts by mass Photosensitizer (KAYACURE DETX-S, manufactured by Nippon Kayaku) 1.00 part by mass Leveling agent T-1 0.08 parts by mass Methyl ethyl ketone 2840.00 parts by mass -----------------------------------

[0107] Liquid crystal compound L-1

[0108] Chiral agent A

[0109] Leveling agent T-1

[0110] The first optically anisotropic layer was formed by applying composition A-1 in multiple layers onto alignment film P-1. First, composition A-1 was applied as a first layer onto the alignment film, heated, cooled, and then cured with UV light to form a liquid crystal fixing layer. After that, subsequent layers were applied by recoating the liquid crystal fixing layer, and similarly heated, cooled, and then cured with UV light, repeatedly.

[0111] First, for the first layer, the following composition A-1 was applied to the alignment film P-1, and the coating film was heated to 70°C on a hot plate, then cooled to 25°C, and then irradiated with ultraviolet light of 365 nm wavelength at 300 mJ / cm using a high-pressure mercury lamp in a nitrogen atmosphere. 2 The coating film was irradiated with light at an irradiation dose of 1000 .mu.m, thereby fixing the alignment of the liquid crystal compound. At this time, the thickness of the first liquid crystal layer was 0.2 .mu.m.

[0112] The second and subsequent layers were coated on top of the liquid crystal layer, heated and cooled under the same conditions as above, and then cured with ultraviolet light to form a liquid crystal fixing layer. In this manner, coating was repeated until the desired total thickness was reached, thereby forming a first optically anisotropic layer.

[0113] <<Formation of Second Optically Anisotropic Layer>> The following composition A-1 was prepared as a liquid crystal composition for forming the second optically anisotropic layer. Composition A-1 ----------------------------------- Liquid crystal compound L-1 100.00 parts by mass Polymerization initiator (Irgacure (registered trademark) 907, manufactured by BASF) 3.00 parts by mass Photosensitizer (KAYACURE DETX-S, manufactured by Nippon Kayaku) 1.00 part by mass Leveling agent T-1 0.08 parts by mass Methyl ethyl ketone 2840.00 parts by mass

[0114] A second optically anisotropic layer was formed on the first optically anisotropic layer in the same manner as for the first optically anisotropic layer, except that the composition A-1 was used and the film thickness was changed.

[0115] <<Formation of Third Optically Anisotropic Layer>> The following composition A-8 was prepared as a liquid crystal composition for forming an optically anisotropic layer.

[0116] Composition A-8 ----------------------------------- Liquid crystal compound L-1 100.00 parts by mass Chiral agent B 0.32 parts by mass Polymerization initiator (Irgacure (registered trademark) 907, manufactured by BASF) 3.00 parts by mass Photosensitizer (KAYACURE DETX-S, manufactured by Nippon Kayaku) 1.00 part by mass Leveling agent T-1 0.08 parts by mass Methyl ethyl ketone 2840.00 parts by mass -----------------------------------

[0117] Chiral agent B

[0118] A third optically anisotropic layer was formed on the second optically anisotropic layer in the same manner as for the first optically anisotropic layer, except that composition A-8 was used, to form an optically anisotropic layer having a three-layer structure.

[0119] The first optically anisotropic layer and the third optically anisotropic layer finally had a liquid crystal Δn940 × thickness = Re(940) of 470 nm, and the second optically anisotropic layer had a Δn940 × thickness (Re(940)) of 564 nm. Furthermore, a polarizing microscope confirmed that the liquid crystal surface had a concentric periodic alignment pattern as shown in Figure 6. In the liquid crystal alignment pattern of this first optically anisotropic layer, one period was very large at the center (the reciprocal of the period can be considered to be 0), 9.0 μm at a distance of 1.0 mm from the center, 4.5 μm at a distance of 2.5 mm from the center, and 3.0 μm at a distance of 4.0 mm from the center, with the period becoming shorter toward the outside. The twist angle in the thickness direction of the first optically anisotropic layer was a right twist of 130°. The twist angle in the thickness direction of the second optically anisotropic layer was 0°, and the twist angle in the thickness direction of the third optically anisotropic layer was 130° leftward. The twist directions of the first optically anisotropic layer and the third optically anisotropic layer were opposite. Furthermore, in the cross-sectional SEM image, bright and dark lines obliquely inclined with respect to the normal to the interface below the optically anisotropic layer were observed in the first optically anisotropic layer and the third optically anisotropic layer, while bright and dark lines extending along the normal were observed in the second optically anisotropic layer. In the first and third optically anisotropic layers, the inclination angle of the bright and dark lines with respect to the normal to the first optically anisotropic layer decreased from the center to the outside, and the inclination direction of the bright and dark lines with respect to the normal to the first optically anisotropic layer and the third optically anisotropic layer was opposite. It was observed that the period of the bright and dark line patterns shortened from the center to the outside in all of the first optically anisotropic layer, the second optically anisotropic layer, and the third optically anisotropic layer.

[0120] [Example 2] A laminate was prepared in the same manner as in Example 1, except that the height of the pins used to heat the coating film of the composition (liquid crystal composition) (to align the liquid crystal compound) was set to 0.3 mm. [Example 3] A laminate was prepared in the same manner as in Example 1, except that the thickness of the substrate (alkali-free glass) was set to 1.1 mm. [Example 4] A laminate was prepared in the same manner as in Example 1, except that the height of the pins used to heat the coating film of the composition was set to 0.3 mm and the thickness of the substrate was set to 1.1 mm.

[0121] [Example 5] A laminate was produced in the same manner as in Example 4, except that the substrate was changed to borosilicate glass. The thermal expansion coefficient of this substrate was 5 × 10 -6 / °C. [Example 6] A laminate was produced in the same manner as in Example 4, except that the substrate was changed to quartz glass. The thermal expansion coefficient of this substrate was 0.5 × 10 -6 / °C. [Example 7] A laminate was produced in the same manner as in Example 4, except that the substrate was changed to an aluminosilicate truss. The thermal expansion coefficient of this substrate was 8.9 × 10 -6 / ℃.

[0122] [Example 8] A laminate was produced in the same manner as in Example 4, except that the substrate was changed to soda glass. The thermal expansion coefficient of this substrate was 9.2 × 10 -6 / ° C. [Example 9] A laminate was produced in the same manner as in Example 8, except that the thickness of the substrate was changed to 2 mm.

[0123] [Comparative Example 1] A laminate was prepared in the same manner as in Example 8, except that no pins were used (pin height: 0 mm) when heating the coating film of the composition (liquid crystal composition). [Comparative Example 2] A laminate was prepared in the same manner as in Example 8, except that the thickness of the substrate (soda glass) was changed to 4 mm.

[0124] Comparative Example 3 A laminate was produced in the same manner as in Example 9, except that the substrate was changed to stainless steel (SUS340). The thermal expansion coefficient of this substrate was 17×10 -6 / °C. [Comparative Example 4] A laminate was produced in the same manner as in Example 9, except that the substrate was changed to a polyethylene terephthalate (PET) film. The thermal expansion coefficient of this substrate was 65 × 10 -6 / °C. Comparative Example 5 A laminate was produced in the same manner as in Example 9, except that the substrate was changed to a polycarbonate film. The thermal expansion coefficient of this substrate was 70 × 10 -6 / ℃.

[0125] [Evaluation] The laminates thus produced were evaluated for warpage of the substrate, in-plane temperature unevenness, thickness unevenness of the optically anisotropic layer, light leakage, and positional accuracy of the optical members.

[0126] <Warping of substrate> During heating, the substrate was visually observed from the side of the hot plate and subjected to a sensory evaluation of warping. The evaluation was as follows: A: No warping B: Warping (the lowest point of the warped substrate was above the center of the pin height) C: Moderate warping (the lowest point of the warped substrate was near the center of the pin height) D: Severe warping (the substrate was warped so much that it came into contact with the hot plate or floated away from the pins)

[0127] <In-plane temperature unevenness> The in-plane temperature distribution of the substrate was measured by contacting a thermocouple. If the in-plane temperature distribution (maximum temperature - minimum temperature [°C]) was within 4°C, it was considered good, if it was within 10°C it was within the acceptable range, and if it exceeded 10°C it was considered out of the acceptable range (NG).

[0128] <Thickness Unevenness> The thickness unevenness of the optically anisotropic layer was measured using an interference film thickness meter. Measurements were made over the entire surface at 10 mm intervals. The evaluation was as follows: A: Thickness unevenness is less than ±2% relative to the average film thickness; B: Thickness unevenness is ±2% or more but less than ±4% relative to the average film thickness; C: Thickness unevenness is 4% or more relative to the average film thickness.

[0129] <Leakage Light> For each of the 40 x 40 mm optical elements, an evaluation device was assembled so that collimated right-handed circularly polarized light with a wavelength of 532 nm was incident on the optically anisotropic layer at an incident angle of 30° (the angle relative to the normal direction of the surface of the optically anisotropic layer), and the light that emerged without diffracting passed through a left-handed circular polarizer (a polarizer that transmits left-handed circularly polarized light) and was perpendicularly incident on a detector. The ratio (%) of the intensity of the light that emerged without diffracting to the intensity of the incident light [(intensity of light that emerged without diffracting / intensity of incident light) x 100] was measured as the magnitude of leakage light. Measurements were performed on 56 sheet samples (8 rows of long sides, 7 rows of short sides) at four locations for each optical element. Evaluations were as follows: A: Maximum leakage light was 2% or less; B: Maximum leakage light was greater than 2% but less than 5%; C: Maximum leakage light was greater than 5%.

[0130] <Positional Accuracy of Optical Elements> In this example, as conceptually shown in FIG. 10 , 40 x 40 mm optical elements were formed on a 400 x 350 mm substrate, with 8 optical elements on the long side and 7 on the short side, spaced 2 mm apart, in an 8 x 7 array. The optically anisotropic layer was peeled off using an adhesive sheet, and as shown in FIG. 10 , the optical element A in the upper left corner of the figure was used as a reference. The distance between the lower right corner (black circle) of this reference and the lower right corner (black circle) of the seventh optical element B on the long side, and the distance between the lower right corner (black circle) of the seventh optical element C on the short side were measured. The design values ​​for both distances were both 252 mm. The positional accuracy of the optical elements was evaluated using the difference between the larger of the two measured distances and the design value. A length measuring instrument (Keyence Corporation's IM-8000 image dimension measuring instrument) was used to measure the positional accuracy. The evaluation was as follows: A: The difference in distance is less than 100 μm. B: The difference in distance is more than 100 μm and less than 200 μm. C: The difference in distance is more than 200 μm and less than 500 μm. D: The difference in distance is more than 500 μm. The results are shown in the table below.

[0131]

[0132] As shown in the table above, the laminate of the present invention is better than the comparative example in terms of substrate warpage, thickness unevenness, and positional accuracy. Also, as mentioned above, in-plane temperature unevenness is good if it is within 4°C, and outside the acceptable range if it exceeds 10°C, but while all the comparative examples are NG, all the laminates of the present invention are good. From the above results, the effect of the present invention is clear.

[0133] The present invention can be suitably used for manufacturing optical members used in various optical devices.

[0134] REFERENCE SIGNS LIST 10 Laminate 12 Substrate 14 Alignment film 14a Unexposed alignment film 16 Optically anisotropic layer 20 Optical member 30 Hot plate 32 Pin 40 Liquid crystal compound 52, 54 Coating means 80 Exposure device 82 Laser 84 Light source 86 Polarizing beam splitter 90A, 90B Mirror 92 Lens 94 Beam splitter 96 λ / 4 plate

Claims

1. A method for manufacturing an optically anisotropic layer, comprising: Step 1, forming an alignment film having a non-aligned region and a plurality of pattern-aligned regions on a substrate; Step 2, applying a composition containing a liquid crystal compound having a polymerizable group onto the alignment film to form a coating film; Step 3, heating the coating film from the substrate side to align the liquid crystal compound in the pattern-aligned region; and Step 4, exposing the coating film to light to form an optically anisotropic layer having a non-aligned region in which the liquid crystal compound is not aligned and a plurality of liquid crystal alignment regions in which the liquid crystal compound is aligned; -6 / °C or less, a thickness of the substrate is 2 mm or less, and in step 3, the coating film is heated while a heat source for the coating film and the substrate are spaced apart.

2. The method for producing a laminate according to claim 1, wherein in step 3, the distance between the heat source for the coating film and the substrate is 0.1 to 1 mm.

3. The method for producing a laminate according to claim 1 or 2, wherein in step 3, the heat source for the coating film is spaced from the substrate by a plurality of pins provided on the heat source.

4. The method for manufacturing a laminate according to claim 3, wherein the plurality of pins are spaced apart from one another, and the distance between the pins is 7 to 30 cm.

5. The method for producing a laminate according to claim 1 or 2, further comprising, after step 4, step 5 of peeling the alignment film and the substrate from the optically anisotropic layer, or peeling the substrate from the alignment film.

6. A laminate comprising a substrate, an alignment film having a non-aligned region and a plurality of patterned alignment regions, and an optically anisotropic layer including a non-aligned region in which a liquid crystal compound is not aligned and a plurality of liquid crystal alignment regions in which the liquid crystal compound is aligned, wherein the thermal expansion coefficient of the substrate is 10×10 -6 / °C or less, and the thickness of the substrate is 2 mm or less.

7. The laminate according to claim 6, wherein the distance between the plurality of liquid crystal alignment domains is 0.5 to 10 mm.

8. A laminate according to claim 6 or 7, wherein the liquid crystal orientation region of the optically anisotropic layer has a liquid crystal orientation pattern in which the direction of the optical axis derived from the liquid crystal compound changes while rotating continuously along at least one direction in the plane, and when the length of a 180° rotation of the direction of the optical axis derived from the liquid crystal compound in the plane is defined as one period, the length of one period in the liquid crystal orientation pattern is an area in the plane.

9. The laminate according to claim 6 or 7, wherein the substrate is alkali-free glass and has a thickness of 1.2 mm or less.

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