Optical laminate

Abstract

Provided is an optical laminate capable of preventing a corner part of an optical functional layer from peeling off a support due to shrinkage of the optical functional layer. The present invention has a first laminate, which has a support and an optical functional layer that is laminated on the support and is formed using a liquid crystal composition containing a liquid crystal compound. The coefficient of thermal expansion of the support is less than 1 × 10-5 / °C. The optical functional layer has a liquid crystal alignment pattern in which the orientation of the optical axis derived from the liquid crystal compound changes continuously in rotation along at least one in-plane direction. In the first laminate, the end face of the support and the end face of the optical functional layer are flush with one another. The end face of the first laminate has an end-face coating layer that covers the position of the interface between the support and the optical functional layer. When viewed from a direction perpendicular to a main face of the first laminate, the end-face coating layer covers a range of 10% or more of the length of the sides from respective corners of the main face of the first laminate.

Description

optical laminate

[0001] The present invention relates to an optical laminate.

[0002] It has been proposed to use an optical laminate having an optically functional layer using a liquid crystal material as an optical member having the functions of a diffraction element, a lens, or the like.

[0003] An optically functional layer using a liquid crystal material exhibits a desired function by aligning the liquid crystal compound in a predetermined orientation pattern. To align the liquid crystal compound in the optically functional layer in a predetermined orientation state, the optically functional layer is formed by applying a liquid crystal composition containing the liquid crystal compound onto an alignment film having an alignment function and curing the applied composition.

[0004] For example, Patent Document 1 discloses a method for manufacturing an optical element having an optically anisotropic layer formed using a liquid crystal composition containing a liquid crystal compound, an alignment film for aligning the liquid crystal compound, and a support, the method comprising an alignment film forming step of forming an alignment film on one surface of the support, and an optically anisotropic layer forming step of forming an optically anisotropic layer on the alignment film, the alignment film containing a photoalignment material, an exposure step of exposing different positions in the plane of the alignment film to light with different polarization directions, and the support scattering light in at least a part of the wavelength range of the light absorption band in which a photochemical reaction of the alignment film occurs by irradiating the support with polarized light in the exposure step.

[0005] International Publication No. 2020 / 022513

[0006] Incidentally, from the viewpoint of improving productivity when producing an optically functional layer using the liquid crystal compound as described above, the inventors considered forming multiple regions having a predetermined liquid crystal orientation pattern in a liquid crystal layer coated on a support (alignment film), and cutting out the regions including each liquid crystal orientation pattern to produce multiple optical laminates having an optically functional layer.

[0007] However, it has been found that when the optical functional layer is cut out together with the support, a problem occurs in that the corners of the optical functional layer are peeled off from the support due to shrinkage of the optical functional layer.

[0008] The object of the present invention is to solve the problems of the conventional technology and to provide an optical laminate that can prevent the corners of the optical functional layer from peeling off from the support due to shrinkage of the optical functional layer.

[0009] In order to solve this problem, the present invention has the following configuration: [1] A first laminate including a support and an optically functional layer laminated on the support and formed using a liquid crystal composition containing a liquid crystal compound, wherein the thermal expansion coefficient of the support is 1×10 -5 / °C or less, the optical functional layer has a liquid crystal alignment pattern in which the orientation of the optical axis derived from the liquid crystal compound changes while continuously rotating along at least one direction in the plane, the end faces of the support of the first laminate and the end faces of the optical functional layer are flush with each other, and the first laminate has an end covering layer covering the interface between the support and the optical functional layer at the end face, wherein the end covering layer covers an area of ​​10% or more of the length of each side from each corner of the main surface of the first laminate when viewed in a direction perpendicular to the main surface of the first laminate. [2] The optical laminate according to [1], wherein the end covering layer covers an area of ​​50% or more of the length of each side of the main surface of the first laminate when viewed in a direction perpendicular to the main surface of the first laminate. [3] The optical laminate according to [1] or [2], wherein the end covering layer is an organic material and has a thickness of 1 μm to 1 mm in a direction perpendicular to the end face of the first laminate. [4] The optical laminate according to [1] or [2], wherein the edge covering layer is an inorganic substance and has a thickness of 10 nm to 500 nm in a direction perpendicular to the edge faces of the first laminate. [5] The optical laminate according to [1], wherein the edge covering layer covers the edge faces from a portion of at least one main surface of the first laminate. [6] The optical laminate according to [5], wherein the edge covering layer covers the edge faces from a portion of the main surface of the first laminate facing the optical functional layer. [7] The optical laminate according to [5], wherein the edge covering layer covers the edge faces from a portion of the main surfaces on both sides of the first laminate. [8] The optical laminate according to any one of [5] to [7], wherein the width from the edge faces of the raised portions of the edge covering layer formed on the main surfaces of the first laminate is 0.01 mm or more. [9] The optical laminate according to any one of [5] to [7], wherein the edge covering layer is an organic substance and the height of the raised portions formed on the main surfaces of the first laminate in a direction perpendicular to the main surfaces is 1 μm to 1 mm.

[10] The optical laminate according to any one of [5] to [7], wherein the edge covering layer is an inorganic material, and the height of the raised portion formed on the main surface of the first laminate in the direction perpendicular to the main surface is 10 nm to 500 nm.

[11] The optical laminate according to [1] or [2], wherein the peel strength of the edge covering layer from the support and the optically functional layer is 4 N / cm or more.

[12] The optical laminate according to [1] or [2], wherein the material of the support includes any one of glass, quartz, and silicon.

[13] The optical laminate according to [1] or [2], wherein the end surface covering layer is an organic material and contains any one of an acrylic resin, an epoxy resin, and a silicone resin.

[14] The optical laminate according to [1] or [2], wherein the end surface covering layer is an organic material and contains a light-absorbing material.

[15] The optical laminate according to [1] or [2], wherein the optical functional layer is formed using a liquid crystal composition containing a polymerizable liquid crystal compound and is a cured film obtained by polymerizing the polymerizable liquid crystal compound.

[16] The optical laminate according to [1] or [2], wherein the first laminate is a cut-out product.

[0010] According to the present invention, it is possible to provide an optical laminate that can prevent the corners of the optical functional layer from peeling off from the support due to shrinkage of the optical functional layer.

[0011] FIG. 1 is a front view conceptually showing an example of the optical laminate of the present invention. FIG. 2 is a cross-sectional view along line A-A of the optical laminate shown in FIG. 1. FIG. 3 is a cross-sectional view conceptually showing another example of the optical laminate of the present invention. FIG. 4 is a cross-sectional view conceptually showing another example of the optical laminate of the present invention. FIG. 5 is a conceptual view for explaining an example of an optical functional layer possessed by the optical laminate of the present invention. FIG. 6 is a partial cross-sectional view of the optical laminate shown in FIG. 7. FIG. 7 is a conceptual view for explaining an optical functional layer. FIG. 8 is a cross-sectional view conceptually showing another example of the optical functional layer. FIG. 9 is a conceptual view for explaining a method for producing the optical laminate of the present invention. FIG. 10 is a diagram conceptually showing an example of an exposure apparatus that exposes an alignment film for forming an optical functional layer. FIG. 11 is a diagram conceptually showing another example of an exposure apparatus that exposes an alignment film for forming an optical functional layer.

[0012] The optical laminate of the present invention will be described in detail below with reference to preferred embodiments shown in the accompanying drawings.

[0013] It should be noted that the drawings shown below are conceptual diagrams for explaining the present invention, and the shape, size (size ratio), positional relationship, etc. of each component element may differ from the actual ones.

[0014] In the present invention, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits.

[0015] [Optical Laminate] The optical laminate of the present invention includes a first laminate having a support and an optically functional layer laminated on the support and formed using a liquid crystal composition containing a liquid crystal compound, and the support has a thermal expansion coefficient of 1×10 -5 / °C, the optical functional layer has a liquid crystal orientation pattern in which the direction of the optical axis derived from the liquid crystal compound changes while continuously rotating along at least one direction in the plane, the end face of the support in the first laminate and the end face of the optical functional layer are flush with each other, the first laminate has an end face covering layer that covers the interface between the support and the optical functional layer at the end face of the first laminate, and when viewed from a direction perpendicular to the main surface of the first laminate, the end face covering layer covers an area of ​​10% or more of the length of each side from each corner of the main surface of the first laminate.

[0016] Fig. 1 is a front view conceptually showing an example of the optical laminate of the present invention, and Fig. 2 is a cross-sectional view of the optical laminate shown in Fig. 1 taken along line AA.

[0017] The optical laminate 10 shown in FIGS. 1 and 2 has a first laminate 14 having a support 18 and an optically functional layer 12 , and an end surface covering layer 20 that covers part of the end surface of the first laminate 14 .

[0018] As will be described later, the first laminate 14 is preferably formed by cutting out a region corresponding to one optical functional layer from a laminate in which a liquid crystal layer, in which a plurality of regions (regions having a liquid crystal orientation pattern) that will become optical functional layers, are formed on a support. Therefore, in the first laminate 14, the end face of the support 18 and the end face of the optical functional layer 12 are flush with each other. The end face covering layer 20 is formed on the end faces of the support 18 and the optical functional layer 12 that are flush with each other.

[0019] In the present invention, the edge surface of the support 18 and the edge surface of the optical functional layer 12 being flush means that the difference in level between the edge surface of the support 18 and the edge surface of the optical functional layer 12 is less than 1 mm. The difference in level between the edge surface of the support 18 and the edge surface of the optical functional layer 12 is preferably less than 1 mm, more preferably 0.1 mm or less, and even more preferably 0.0005 mm or less. By having the difference in level between the edge surface of the support 18 and the edge surface of the optical functional layer 12 be less than 1 mm, peeling of the optical functional layer 12 can be suppressed before the edge covering layer 20 is formed.

[0020] 2 , the edge covering layer 20 covers at least the position of the interface B between the support 18 and the optically functional layer 12 on the edge face of the first laminate 14. That is, the edge covering layer 20 is formed in a region of the edge face of the first laminate 14 in the thickness direction that includes the position of the interface B between the support 18 and the optically functional layer 12.

[0021] 1 , the first laminate 14 has a rectangular shape when viewed in a direction perpendicular to the main surface, and an edge covering layer 20 is formed in each region including the corners of the main surface. In other words, the edge covering layer 20 is formed in a region of a predetermined length from the end of each side of the first laminate 14 when viewed in a direction perpendicular to the main surface. The main surface is the largest surface of the sheet-like material, and in the first laminate 14, it is a surface perpendicular to the stacking direction of the support 18 and the optically functional layer 12.

[0022] In the present invention, on each side of the main surface of the first laminate 14, the edge covering layer 20 covers an area extending from each corner of the main surface of the first laminate 14 over 10% or more of the length of each side. That is, as shown in Fig. 1 , when viewed from a direction perpendicular to the main surface of the first laminate 14, the edge covering layer 20 is provided in two locations, one at each end of each side of the main surface of the first laminate 14, and each of the lengths is 10% or more of the length L of the side (0.1L or more). The length of the edge covering layer 20 is defined as the length at the position of the interface B between the support 18 and the optically functional layer 12.

[0023] As described above, from the viewpoint of improving productivity when producing an optically functional layer using a liquid crystal compound, the inventors considered forming multiple regions having a predetermined liquid crystal orientation pattern in a liquid crystal layer coated on a support (alignment film), and cutting out the regions including each liquid crystal orientation pattern to produce multiple optical laminates having an optically functional layer.

[0024] However, it has been found that in an optical laminate in which an optical functional layer is cut out together with a support, the optical functional layer shrinks over time due to changes in the temperature and humidity of the ambient environment, causing the corners of the optical functional layer to peel off from the support. In particular, when a support with a small thermal expansion coefficient is used, the difference in thermal expansion coefficient between the support and the optical functional layer becomes large, and this problem is likely to occur.

[0025] Furthermore, the inventors' studies have found that when an optically functional layer has a liquid crystal orientation pattern in which the optical axis of the liquid crystal compound changes while continuously rotating along one in-plane direction, the problem of peeling off at the corners of the optically functional layer from the support is likely to occur. For example, in the case of an optically functional layer (liquid crystal layer) in which the optical axis of the liquid crystal compound is oriented in a predetermined direction, such as used as a retardation layer, the layer exhibits anisotropy in shrinkage, i.e., it is difficult to shrink in the direction of the optical axis but easy to shrink in a direction perpendicular to the optical axis. Specifically, for example, in the case of rod-shaped liquid crystal compounds, the long axis direction is the optical axis, and when the optical axis of the liquid crystal compound is oriented in a predetermined direction, the rod-shaped liquid crystal compounds are aligned along the long axis. Therefore, in this direction, a force is generated that resists internal shrinkage stress, making it difficult to shrink. In this case, the problem of peeling off at the corners of the optically functional layer from the support is unlikely to occur. In contrast, in the case of an optically functional layer having a liquid crystal orientation pattern in which the optical axis of the liquid crystal compound changes while continuously rotating along one in-plane direction, the shrinkage of the optically functional layer is isotropic when viewed macroscopically. When the optical functional layer shrinks isotropically, stress is concentrated at the corners of the optical functional layer, which is likely to cause the corners of the optical functional layer to peel off from the support.

[0026] In contrast, the optical laminate of the present invention has an edge covering layer 20 that covers the position of the interface B between the support 18 and the optical functional layer 12 on the edge of the first laminate 14 having the support 18 and the optical functional layer 12, and when viewed from a direction perpendicular to the main surface of the first laminate 14, the edge covering layer 20 has a configuration in which it covers an area extending from each corner of the main surface of the first laminate 14 to 10% or more of the length of each side. This makes it possible to prevent the corners of the optical functional layer from peeling off from the support.

[0027] Here, from the viewpoint of suppressing peeling of the optical functional layer, the length of the end surface covering layer 20 from each corner of the main surface of the first laminate 14 when viewed from a direction perpendicular to the main surface of the first laminate 14 is preferably 10% or more of the length L of each side, more preferably 35% or more, and most preferably a length that covers the entire area of ​​each side.

[0028] When viewed from a direction perpendicular to the main surface of the first laminate 14, the length of the end surface covering layer 20 from each corner on a side of the main surface of the first laminate 14 may be the same or different.

[0029] Furthermore, when viewed from a direction perpendicular to the main surface of the first laminate 14, the length of the edge covering layer 20 from the corner on one side of the main surface of the first laminate 14 and the length of the edge covering layer 20 from the corner on another side may be the same or different.

[0030] Furthermore, when viewed from a direction perpendicular to the main surface of the first laminate 14, the total length of the end covering layer 20 relative to the length L of each side of the main surface of the first laminate 14 is preferably 50% or more of the length of each side, more preferably 80% or more, and most preferably a length that covers the entire area of ​​each side. In other words, the length of the area not covered by the end covering layer 20 on each side of the main surface of the first laminate 14 is preferably less than 50% of the length L of each side (less than 0.5L (see FIG. 1 )).

[0031] 1, the edge covering layer 20 is formed on both ends of each side of the main surface of the first laminate 14 when viewed from a direction perpendicular to the main surface of the first laminate 14. However, this is not limiting, and the edge covering layer 20 may be formed in the middle region in addition to both ends of each side. In this case, it is sufficient that the total length of the edge covering layer 20 formed on both ends and the edge covering layer 20 formed in the middle is 50% or more of the length of the side.

[0032] In the example shown in FIG. 1 , the shape of the first laminate 14 when viewed from a direction perpendicular to the main surface of the first laminate 14 is rectangular, but this is not limited to this and may be any polygonal shape, such as a triangular shape or a pentagonal shape, as long as it has corners.

[0033] 1, when viewed from a direction perpendicular to the main surface of the first laminate 14, the edge covering layer 20 is formed on all sides of the main surface of the first laminate 14, but this is not limiting and the edge covering layer 20 may be formed on at least one side of the main surface of the first laminate 14. From the viewpoint of suppressing peeling of the optical functional layer, a configuration in which the edge covering layer 20 is formed on all sides of the main surface of the first laminate 14 is preferred.

[0034] Furthermore, the thickness d (see FIG. 2 ) of the end surface covering layer 20 in the direction perpendicular to the end surface of the first laminate 14 may be appropriately set depending on the material from which the end surface covering layer 20 is formed. When the material from which the end surface covering layer 20 is formed is an organic substance, the thickness d of the end surface covering layer 20 is preferably 1 μm to 1 mm, more preferably 1 μm to 100 μm, and even more preferably 1 μm to 20 μm. When the material from which the end surface covering layer 20 is formed is an inorganic substance, the thickness d of the end surface covering layer 20 is preferably 10 nm to 500 nm, more preferably 10 nm to 200 nm, and even more preferably 10 nm to 100 nm. By setting the thickness d of the end surface covering layer 20 within the above range, peeling of the corners of the optically functional layer 12 from the support 18 can be more effectively prevented. The material from which the end surface covering layer is formed will be described in detail below.

[0035] The peel strength of the edge covering layer 20 between the support 18 and the optical functional layer 12 is preferably 4 N / cm or more, and more preferably 8 N / cm or more. By setting the peel strength of the edge covering layer 20 between the support 18 and the optical functional layer 12 to 4 N / cm or more, peeling of the corners of the optical functional layer 12 from the support 18 can be more suitably prevented.

[0036] The peel strength of the edge covering layer 20 from the support 18 and the optically functional layer 12 can be evaluated by attaching an adhesive tape with a peel strength of 4 N / cm to the edge covering layer and pulling the adhesive tape in a 90° direction using a peel tester, and determining whether the edge covering layer is transferred to the adhesive tape. The peel strength of the edge covering layer 20 from the support 18 and the optically functional layer 12 can also be measured by performing a similar test using adhesive tapes with multiple different peel strengths. The peel strength can also be measured in accordance with the general 90° peel test method of JIS Z 0237, for example, by using a jig capable of clamping the thin edge covering layer 20 and performing a 90° peel test using a Shimadzu AGS-X tensile tester.

[0037] In addition, in the example shown in Figure 2, the end surface covering layer 20 is configured to cover a portion of the first laminate 14 in the thickness direction, including the position of interface B between the support 18 and the optical functional layer 12 (hereinafter simply referred to as the position of interface B), but this is not limited to this.

[0038] As in the optical laminate 10b shown in Fig. 3, the end surface covering layer 20b may be configured to cover from a portion of one main surface of the first laminate 14 to the end surface. In the example shown in Fig. 6, in the optical laminate 10b, the end surface covering layer 20b is formed from a portion of the main surface of the first laminate 14 on the optical functional layer 12 side to an area of ​​the end surface including the position of the interface B.

[0039] 4, the end covering layer 20c may be configured to cover from a portion of the main surface on both sides of the first laminate 14 to the end faces. That is, as shown in Fig. 4, the end covering layer 20c is formed from a portion of the main surface of the first laminate 14 on the optical functional layer 12 side to the entire end faces in the thickness direction, and further to a portion of the main surface of the first laminate 14 on the support 18 side.

[0040] In this way, by configuring the end surface covering layer to be formed on a portion of at least one of the main surfaces of the first laminate 14, it is possible to more effectively prevent the corners of the optically functional layer 12 from peeling off from the support 18.

[0041] 3 and 4 , in a configuration in which the edge covering layer is formed on a portion of at least one of the main surfaces of the first laminate 14, if the portion of the edge covering layer formed on the main surface of the first laminate 14 is defined as a rising portion, the width w (see FIG. 4 ) of the rising portion from the edge surface of the first laminate 14 is preferably 0.01 mm or more, more preferably 0.01 mm to 1 mm, and even more preferably 0.05 mm to 0.3 mm. By setting the width w of the rising portion to be 0.01 mm or more, peeling of the corners of the optically functional layer 12 from the support 18 can be more suitably suppressed.

[0042] The height h (see FIG. 4) of the rising portion of the end face covering layer from the main surface of the first laminate 14 may be set appropriately depending on the material from which the end face covering layer is formed. When the material from which the end face covering layer is formed is organic, the height h of the rising portion is preferably 1 μm to 1 mm, more preferably 1 μm to 100 μm, and even more preferably 1 μm to 20 μm. When the material from which the end face covering layer is formed is inorganic, the height h of the rising portion is preferably 10 nm to 500 nm, more preferably 10 nm to 200 nm, and even more preferably 10 nm to 100 nm.

[0043] The components of the optical laminate will be described below.

[0044] [First Laminate] The first laminate 14 includes a support 18 and an optically functional layer 12 laminated on the support 18. The first laminate 14 may be formed by forming the optically functional layer 12 directly on the alignment film of the support 18, or by forming the optically functional layer 12 on a separate temporary support and then transferring it to the substrate. When forming the first laminate 14 by transferring the optically functional layer 12 to the substrate, the optically functional layer 12 is preferably laminated to the substrate via an adhesive layer. In this case, the laminate of the substrate and the adhesive layer corresponds to the support 18. The optically functional layer 12 requires smoothness to achieve appropriate optical performance. Therefore, when transferring to the substrate using an adhesive layer, it is desirable to use a thin adhesive layer with a thickness of 10 μm or less. However, when using a thin adhesive layer, it is difficult to strengthen the adhesion between the substrate and the optically functional layer, which can lead to the problem of the optically functional layer peeling from the corners.

[0045] <Support> The support 18 is a member for supporting the optically functional layer 12. The support 18 may be made of a single substrate such as a glass substrate or a resin substrate, or may have a configuration in which an alignment film is laminated on such a substrate. Alternatively, the support 18 may have a configuration in which a substrate and an adhesive layer are laminated.

[0046] (Substrate) The substrate preferably has a transmittance of 50% or more, more preferably 70% or more, and even more preferably 85% or more, for light of a wavelength that the optically functional layer is effective against.

[0047] There is no limitation on the thickness of the substrate, and it may be set appropriately depending on the application of the optical laminate and the material forming the substrate, etc., so as to have a thickness that can support the optical functional layer 12. The thickness of the substrate is preferably 1 to 1000 μm, more preferably 3 to 250 μm, and even more preferably 5 to 150 μm.

[0048] The substrate may be single-layer or multi-layer. In the case of a single layer, the substrate may be a substrate made of glass, quartz, silicon, or the like, or a resin substrate made of triacetyl cellulose (TAC), polyethylene terephthalate (PET), polycarbonate, polyvinyl chloride, acrylic, polyolefin, or the like. In the case of a multi-layer substrate, examples include a substrate containing one of the above-mentioned single-layer substrates, with another layer provided on the surface of this substrate. Because of its small thermal expansion coefficient, the present application is suitable for use when using a substrate made of glass, quartz, silicon, or the like. As will be described later, in order to form an optically functional layer having a liquid crystal alignment pattern, it is necessary to form the alignment pattern by irradiating a laser beam onto the alignment film. In this case, there is a risk that the temperature of the substrate will rise due to the irradiated laser beam. However, by using a substrate with a small thermal expansion coefficient, deformation of the alignment pattern caused by deformation of the substrate can be prevented.

[0049] (Alignment Film) The alignment film is an alignment film for aligning the liquid crystal compound in a predetermined liquid crystal alignment pattern when the optically functional layer 12 is formed.

[0050] As will be described later, in the present invention, the optically functional layer 12 has a liquid crystal orientation pattern in which the direction of the optical axis derived from the liquid crystal compound changes while continuously rotating along one direction in the plane (see FIG. 5 ). Therefore, the orientation film is formed so that the optically functional layer 12 can form this liquid crystal orientation pattern.

[0051] Various known alignment films can be used, 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 having microgrooves, and a film formed by accumulating LB (Langmuir-Blodgett) films made of organic compounds such as ω-tricosanoic acid, dioctadecylmethylammonium chloride, and methyl stearate by the Langmuir-Blodgett method.

[0052] An alignment film 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 include polyimide, polyvinyl alcohol, polymers having polymerizable groups as described in JP-A-9-152509, and materials used to form alignment films as described in JP-A-2005-097377, JP-A-2005-099228, and JP-A-2005-128503.

[0053] The alignment film is preferably a so-called photo-alignment film, which is formed by irradiating a photo-alignment material with polarized or non-polarized light. That is, the alignment film is preferably a photo-alignment film formed by applying a photo-alignment material to a substrate. The polarized light can be irradiated perpendicularly or obliquely to the photo-alignment film, and the non-polarized light can be irradiated obliquely to the photo-alignment film.

[0054] Examples of photo-alignment materials used in the alignment film that can be used in the present invention include those described in JP-A-2006-285197, JP-A-2007-076839, JP-A-2007-138138, JP-A-2007-094071, JP-A-2007-121721, JP-A-2007-140465, JP-A-2007-156439, and JP-A-2007-160466. azo compounds described in JP-A-07-133184, JP-A-2009-109831, Japanese Patent No. 3883848 and Japanese Patent No. 4151746, aromatic ester compounds described in JP-A-2002-229039, maleimides having photo-alignable units described in JP-A-2002-265541 and JP-A-2002-317013, and / 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-2014-012823, 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.

[0055] There is no limitation on the thickness of the alignment film, and it may be set appropriately depending on the material of which the alignment film is formed so as to obtain the necessary alignment function. The thickness of the alignment film is preferably 0.01 to 5 μm, and more preferably 0.05 to 2 μm.

[0056] There is no limitation on the method for forming the alignment film, and various known methods can be used depending on the material for forming the alignment film. One example is a method in which an alignment film is applied to the surface of a support and dried, and then the alignment film is exposed to laser light to form an alignment pattern. The method for forming the alignment film will be described in detail later.

[0057] (Adhesive Layer) The adhesive layer is a layer for adhering the optically functional layer 12 to the substrate.

[0058] The adhesive layer can be made of any of a variety of known materials, as long as it can bond the optically functional layer 12 and the substrate together. The adhesive layer may be a layer made of an adhesive that is fluid when bonded and then solidifies, a layer made of a pressure-sensitive adhesive that is a soft, gel-like (rubber-like) solid when bonded and remains gel-like thereafter, or a layer made of a material that has the properties of both an adhesive and a pressure-sensitive adhesive. Therefore, the adhesive layer may be a known layer used to bond sheet-like objects in optical devices, optical elements, etc., such as an optically clear adhesive (OCA), optically clear double-sided tape, or ultraviolet-curable resin.

[0059] In the present invention, the support 18 has a thermal expansion coefficient of 1×10 -5 / °C.

[0060] As described above, in order to form an optically functional layer having a liquid crystal alignment pattern, it is necessary to form the alignment pattern by irradiating the alignment film with a laser beam. In this case, there is a risk that the temperature of the substrate will rise due to the irradiated laser beam, but by using a substrate (support 18) with a small thermal expansion coefficient, it is possible to prevent deformation of the alignment pattern caused by deformation of the support 18.

[0061] From this point, the thermal expansion coefficient of the support 18 is 1×10 -5 / °C. Since it is desirable for the support 18 to have high transmittance and a high refractive index, it is preferable to use optical glass. Generally, the thermal expansion coefficient of optical glass is 1×10 －６ / ℃ to 1×10 －５ / ℃.

[0062] The thermal expansion coefficient of the support 18 can be measured by a known method such as JIS K 7197.

[0063] The thermal expansion coefficient of the support 18 can be determined, for example, by measuring its thermomechanical properties using a thermomechanical analyzer (TMA NETZSCH, TMA4000SE). Measurement conditions include, for example, a sample size of 5 mm x 20 mm, a chuck distance of 15 mm, and a chuck length of 2.5 ± 0.5 mm both at the top and bottom. The temperature is changed at a rate of 5 °C / min between -20 °C and 60 °C, and the amount of change in the chuck distance is measured. The load is measured by applying a constant load of 3 g to the sample. The slope of the approximation line for the data on the amount of change from -20 °C to 60 °C is then calculated to determine the amount of displacement per 1 °C change in temperature. The thermal expansion coefficient can then be calculated by dividing this slope by 15 mm, the distance between the chunks when the sample was set.

[0064] In addition, when the support 18 is a laminate of multiple layers, such as a configuration having a substrate and an alignment film, or a configuration having a substrate and an adhesive layer, the thermal expansion coefficient of the laminate may be within the above range. However, for example, the alignment film may be very thin, and the thermal expansion coefficient of the substrate can essentially be regarded as the thermal expansion coefficient of the support 18.

[0065] <Optical functional layer> The optical functional layer 12 is a layer formed using a liquid crystal composition containing a liquid crystal compound, and is a layer having a liquid crystal orientation pattern in which the direction of the optical axis derived from the liquid crystal compound changes while continuously rotating along at least one direction in the plane.

[0066] Fig. 5 is a diagram conceptually showing an example of a liquid crystal alignment pattern of the optical functional layer 12. Fig. 6 is a partial cross-sectional view of the optical functional layer 12 shown in Fig. 5.

[0067] The optically functional layer 12 shown in FIGS. 5 and 6 acts as a liquid crystal lens, and is a liquid crystal layer formed using a liquid crystal composition containing a liquid crystal compound 40 .

[0068] The optically functional layer 12 has a liquid crystal orientation pattern in which the direction of the optical axis derived from the liquid crystal compound 40 changes while continuously rotating along at least one direction in the plane. In a preferred embodiment, the optically functional layer 12 has regions in the plane where the length of one period is different, where one period is defined as the length of a 180° rotation of the direction of the optical axis derived from the liquid crystal compound 40 in the plane.

[0069] Specifically, the optically functional layer 12 shown in Fig. 5 has a liquid crystal orientation pattern that is radially from the inside to the outside, in which the direction of the optical axis derived from the liquid crystal compound 40 changes while continuously rotating in one direction. That is, the liquid crystal orientation pattern of the optically functional layer 12 shown in Fig. 5 and Fig. 6 is a pattern having a plurality of rings, in which circles with the same direction of the optical axis derived from the liquid crystal compound 40 are arranged in a circle, and circles with different directions of the optical axis are arranged concentrically.

[0070] 5 and 7 described later, in order to simplify the drawings and clearly show the configuration of the optically functional layer 12, only the liquid crystal compound 40 at the interface on the alignment film side of the optically functional layer 12 is shown. However, as shown in Fig. 6, the optically functional layer 12 has a configuration in which liquid crystal compounds 40 are stacked in the thickness direction, similar to a liquid crystal layer formed using a composition containing a normal liquid crystal compound. Furthermore, in Figs. 5 and 6, a rod-shaped liquid crystal compound is shown as an example of the liquid crystal compound 40, and therefore the direction of the optical axis coincides with the longitudinal direction of the liquid crystal compound 40.

[0071] Specifically, in the optical functional layer 12 shown in FIG. 5 , the direction of the optical axis of the liquid crystal compound 40 changes while continuously rotating along multiple directions from the center of the optical functional layer 12 toward the outside, such as the direction indicated by arrow A1, the direction indicated by arrow A2, the direction indicated by arrow A3, the direction indicated by arrow A4, etc. Therefore, in the optical functional layer 12, the rotation direction of the optical axis of the liquid crystal compound 40 is the same in all directions (one direction) from the center toward the outside. In the illustrated example, the rotation direction of the optical axis of the liquid crystal compound 40 is counterclockwise in all one directions indicated by arrow A1, the direction indicated by arrow A2, the direction indicated by arrow A3, and the direction indicated by arrow A4. In other words, if arrows A1 and A4 are considered to be a single line, the rotation direction of the optical axis of the liquid crystal compound 40 is reversed at the center of the optical functional layer 12 on this line. As an example, the line formed by arrows A1 and A4 is assumed to be directed rightward in the figure (the direction of arrow A1). In this case, the optical axis of the liquid crystal compound 40 initially rotates clockwise from the outside toward the center of the optically functional layer 12, reverses the direction of rotation at the center of the optically functional layer 12, and then rotates counterclockwise from the center toward the outside of the optically functional layer 12. The center of the optically functional layer 12 is the optical axis of the liquid crystal lens.

[0072] As is well known, a liquid crystal layer having a liquid crystal orientation pattern in which the direction of the optical axis derived from the liquid crystal compound 40 changes while continuously rotating in one direction acts as a transmissive liquid crystal diffraction element that diffracts incident circularly polarized light in azimuthal directions along one direction in which the optical axis rotates and the opposite direction, depending on the rotation direction of the optical axis and the rotation direction of the incident circularly polarized light.

[0073] In the optical functional layer 12 having a liquid crystal orientation pattern in which the orientation of the optical axis of the liquid crystal compound 40 changes while continuously rotating in one direction, the diffraction direction (refraction direction) of the transmitted light depends on the rotation direction of the optical axis of the liquid crystal compound 40. That is, in this liquid crystal orientation pattern, when the rotation direction of the optical axis of the liquid crystal compound 40 facing in one direction is reversed, the diffraction direction of the transmitted light becomes the opposite direction to the one direction in which the optical axis rotates.

[0074] Furthermore, in the optical functional layer 12 having a liquid crystal orientation pattern in which the orientation of the optical axis of the liquid crystal compound 40 changes while continuously rotating in one direction, the diffraction direction of the transmitted light differs depending on the rotation direction of the incident circularly polarized light. That is, in this liquid crystal orientation pattern, the diffraction direction of the transmitted light is reversed when the incident light is right-handed circularly polarized light and when the incident light is left-handed circularly polarized light.

[0075] Furthermore, when the in-plane retardation (retardation in the plane direction) of the optical functional layer 12 is set to λ / 2, the optical functional layer 12 functions as a general half-wave plate, that is, it has the function of imparting a phase difference of half the wavelength, i.e., 180°, to the polarized light component incident on the liquid crystal layer. Therefore, the circularly polarized light incident on the optical functional layer 12 and diffracted therefrom has the opposite rotation direction. That is, right-handed circularly polarized light incident on the optical functional layer 12 and diffracted therefrom exits as left-handed circularly polarized light, and left-handed circularly polarized light exits as right-handed circularly polarized light.

[0076] In the optically functional layer 12 acting as a liquid crystal lens, when the length of a 180° rotation of the optical axis direction of the liquid crystal compound 40 in one direction in which the direction of the optical axis of the liquid crystal compound 40 changes while continuously rotating is taken as one period, the length of one period gradually shortens from the inside to the outside. That is, the optically functional layer 12 in the illustrated example has regions in its plane where the length of one period differs.

[0077] In a liquid crystal layer having a liquid crystal orientation pattern in which the orientation of the optical axis of the liquid crystal compound 40 changes while continuously rotating in one direction, the shorter the length of one period, the larger the diffraction angle. Therefore, in the optically functional layer 12 having a concentric liquid crystal orientation pattern, the diffraction angle gradually increases from the center of the concentric circle toward the outside.

[0078] Therefore, the optically functional layer 12 having a concentric liquid crystal orientation pattern, in which the optical axis derived from the liquid crystal compound continuously rotates and changes radially, can transmit incident light while diverging or converging it, depending on the rotation direction of the optical axis of the liquid crystal compound 40 and the rotation direction of the incident circularly polarized light. In other words, a liquid crystal lens having such an optically functional layer 12 acts, for example, as a concave lens when right-handed circularly polarized light is incident, and as a convex lens when left-handed circularly polarized light is incident, depending on the rotation direction of the incident circularly polarized light. Alternatively, the optically functional layer 12 acts as a convex lens when right-handed circularly polarized light is incident, and as a concave lens when left-handed circularly polarized light is incident. In the illustrated example, as an example, the optically functional layer 12 acts as a convex lens when left-handed circularly polarized light is incident, converging light, and as a concave lens when right-handed circularly polarized light is incident.

[0079] In the examples shown in Figures 5 and 6, the optically functional layer 12 has a liquid crystal orientation pattern in which the direction of the optical axis of the liquid crystal compound 40 radially changes in one direction while continuously rotating, but this is not limited to this.

[0080] FIG. 7 is a diagram conceptually showing another example of the liquid crystal alignment pattern of the optically functional layer 12. In FIG.

[0081] In addition, even in a concentric liquid crystal orientation pattern in which the optical axis changes while continuously rotating, radially from the inside to the outside, the same optical effect is exhibited as in the liquid crystal orientation pattern shown in Figure 7 with respect to the direction in which the optical axis changes while continuously rotating.

[0082] In the following description, the optical axis 40A originating from the liquid crystal compound 40 will also be referred to as "the optical axis 40A of the liquid crystal compound 40" or "the optical axis 40A".

[0083] In the optical functional layer 12b shown in Fig. 7, the liquid crystal compound 40 is two-dimensionally oriented in a plane parallel to one direction indicated by arrow A and the Y direction perpendicular to the direction of arrow A. In Fig. 6 and Fig. 8 described later, the Y direction is perpendicular to the paper surface. In the following description, "one direction indicated by arrow A" may also be simply referred to as "arrow A direction."

[0084] In the optical functional layer 12 shown in FIG. 5, the circumferential direction of the concentric circles in the concentric liquid crystal alignment pattern corresponds to the Y direction in FIG.

[0085] The optically functional layer 12b has a liquid crystal alignment pattern in which the direction of the optical axis 40A derived from the liquid crystal compound 40 changes while continuously rotating along the direction of the arrow A within the plane of the optically functional layer 12b.

[0086] The direction of the optical axis 40A of the liquid crystal compound 40 changes while continuously rotating in the direction of the arrow A (a predetermined direction), specifically means that the angle formed between the optical axis 40A of the liquid crystal compound 40 aligned along the direction of the arrow A and the direction of the arrow A differs depending on the position in the direction of the arrow A, and the angle formed between the optical axis 40A and the direction of the arrow A changes sequentially from θ to θ+180° or θ−180° along the direction of the arrow A.

[0087] On the other hand, the liquid crystal compounds 40 forming the optically functional layer 12b are arranged at equal intervals in the Y direction perpendicular to the direction of arrow A, i.e., in the Y direction perpendicular to the direction in which the optical axis 40A continuously rotates.

[0088] In other words, in the liquid crystal compounds 40 forming the optically functional layer 12b, the angles formed between the direction of the optical axis 40A and the direction of the arrow A are equal to each other among the liquid crystal compounds 40 aligned in the Y direction.

[0089] In the optical functional layer 12 shown in FIG. 5, regions in which the optical axis 40A is oriented in the same direction are formed in annular shapes that coincide with the center, forming a concentric liquid crystal alignment pattern.

[0090] As described above, in a liquid crystal orientation pattern in which the optical axis 40A rotates continuously in one direction, the length (distance) over which the optical axis 40A of the liquid crystal compound 40 rotates 180° is the length Λ of one period in the liquid crystal orientation pattern.

[0091] 7, one period Λ of the liquid crystal orientation pattern is defined as the length (distance) over which the optical axis 40A of the liquid crystal compound 40 rotates 180° in the direction of arrow A, in which the orientation of the optical axis 40A continuously rotates and changes in the plane. In other words, one period Λ of the liquid crystal orientation pattern is defined as the distance over which the angle between the optical axis 40A of the liquid crystal compound 40 and the direction of arrow A changes from θ to θ+180°.

[0092] In other words, one period Λ is the distance between the centers of two liquid crystal compounds 40 that are arranged at the same angle relative to the direction of arrow A. Specifically, as shown in Fig. 7, one period Λ is the distance between the centers of two liquid crystal compounds 40 whose optical axes 40A and the direction of arrow A coincide with each other.

[0093] In the optically functional layer 12b, the liquid crystal alignment pattern repeats this one period Λ in the direction of arrow A, that is, in one direction in which the direction of the optical axis 40A continuously rotates and changes.

[0094] As described above, the optically functional layer 12b having such a liquid crystal orientation pattern is also a transmission type liquid crystal diffraction element, and this one period Λ is the period (one period) of the diffraction structure.

[0095] In the optical functional layer 12b, the liquid crystal compounds aligned in the Y direction have an optical axis 40A that forms an equal angle with the direction of arrow A. A region R is defined as a region where the liquid crystal compounds 40, whose optical axes 40A and the direction of arrow A form an equal angle, are arranged in the Y direction.

[0096] 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 optically functional layer 12b. Here, the refractive index difference associated with the refractive index anisotropy of region R 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 direction of 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 the liquid crystal compound 40 in the direction of the optical axis 40A and the refractive index of the 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.

[0097] In addition, in a liquid crystal lens having a concentric liquid crystal orientation pattern in which the optical axis 40A has a radial liquid crystal orientation pattern that continuously rotates 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 7.

[0098] When circularly polarized light is incident on the optically functional layer 12b, the light is diffracted and the direction of the circularly polarized light is changed. This effect is explained below. The optically functional layer 12b is assumed to have a value of λ / 2, which is the product of the refractive index difference of the liquid crystal compound and the thickness of the liquid crystal layer.

[0099] As described above, this effect is exactly the same in the liquid crystal lens 34 having a concentric liquid crystal orientation pattern in which the optical axis 40A has a radial liquid crystal orientation pattern that continuously rotates in one direction.

[0100] When the product of the refractive index difference of the liquid crystal compound in the optically functional layer 12b and the thickness of the liquid crystal layer is λ / 2, when left-handed circularly polarized incident light enters the optically functional layer 12b, the incident light is given a phase difference of 180° as it passes through the optically functional layer 12b, and the transmitted light is converted to right-handed circularly polarized light. Furthermore, because the liquid crystal orientation pattern formed in the optically functional layer 12b is a periodic pattern in the direction of arrow A, the transmitted light travels in a direction different from the traveling direction of the incident light. In this way, the left-handed circularly polarized incident light is converted to right-handed circularly polarized transmitted light that is tilted at a certain angle in the direction of arrow A with respect to the incident direction.

[0101] On the other hand, when the product of the refractive index difference of the liquid crystal compound in the optically functional layer 12b and the thickness of the liquid crystal layer is λ / 2, when right-handed circularly polarized incident light enters the optically functional layer 12b, the incident light is given a phase difference of 180° as it passes through the optically functional layer 12b and is converted into left-handed circularly polarized transmitted light. Furthermore, because the liquid crystal orientation pattern formed in the optically functional layer 12b is a periodic pattern in the direction of arrow A, the transmitted light travels in a direction different from the traveling direction of the incident light. At this time, the transmitted light travels in a different direction from the transmitted light, i.e., in the opposite direction from the direction of arrow A relative to the incident direction. In this way, the incident light is converted into left-handed circularly polarized transmitted light tilted at a certain angle in the direction of arrow A relative to the incident direction.

[0102] In the optical functional layer 12b, the in-plane retardation value of the plurality of regions R is preferably a half wavelength, and the in-plane retardation Re(550) = Δn550 × d of the plurality of regions R of the optical functional layer 12b for incident light having a wavelength of 550 nm is preferably within the range defined by the following formula (1): where Δn550 is the refractive index difference associated with the refractive index anisotropy of the regions R when the wavelength of the incident light is 550 nm, and d is the thickness of the optical functional layer 12b: 200 nm ≦ Δn550 × d ≦ 350 nm (1)

[0103] That is, if the in-plane retardation Re(550) = Δn550 × d of the multiple regions R of the optical functional layer 12b satisfies formula (1), a sufficient amount of the circularly polarized component of light incident on the optical functional layer 12b can be converted into circularly polarized light traveling in a direction tilted forward or backward with respect to the direction of arrow A. The in-plane retardation Re(550) = Δn550 × d is more preferably 225 nm ≦ Δn550 × d ≦ 340 nm, and even more preferably 250 nm ≦ Δn550 × d ≦ 330 nm.

[0104] The above formula (1) is a range for incident light with a wavelength of 550 nm, but the in-plane retardation Re(λ)=Δnλ×d of the multiple regions R of the liquid crystal layer for incident light with a wavelength of λ nm is preferably within the range defined by the following formula (1-2), and can be set appropriately: 0.7×(λ / 2)nm≦Δnλ×d≦1.3×(λ / 2)nm (1-2).

[0105] Furthermore, the in-plane retardation values ​​of the multiple regions R in the optical functional layer 12b can be outside the range of the above formula (1). Specifically, by making Δn550×d<200 nm or 350 nm<Δn550×d, light can be separated into light traveling in the same direction as the incident light and light traveling in a direction different from the incident light. As Δn550×d approaches 0 nm or 550 nm, the component of light traveling in the same direction as the incident light increases, and the component of light traveling in a direction different from the incident light decreases.

[0106] As described above, the optical functional layer 12b can adjust the angle of diffraction of transmitted light by changing one period Λ of the formed liquid crystal orientation pattern. Specifically, the shorter one period Λ of the liquid crystal orientation pattern, the stronger the interference between lights that have passed through adjacent liquid crystal compounds 40, and therefore the greater the diffraction of transmitted light.

[0107] Furthermore, the optically functional layer 12b can reverse the direction of diffraction (azimuth direction) of transmitted light by reversing the rotation direction of the optical axis 40A of the liquid crystal compound 40, which rotates along the direction of arrow A.

[0108] Furthermore, as described above, the optical functional layer 12b causes the diffraction direction (azimuth direction) of transmitted light to be opposite depending on the rotation direction of the incident circularly polarized light. That is, the optical functional layer 12b causes the diffraction direction (azimuth direction) of transmitted light to be opposite for right-handed circularly polarized light and left-handed circularly polarized light.

[0109] As mentioned above, the same applies to the optically functional layer 12 having a concentric liquid crystal alignment pattern.

[0110] In the example shown in Fig. 6, the optical axes of the liquid crystal compounds aligned in the thickness direction are aligned in the same direction, but this is not limiting. The optically functional layer may have an in-plane region in which the optical axes of the liquid crystal compounds are twisted along the thickness direction. In this case, the twist angle in the thickness direction region is 10° to 360° throughout the thickness direction.

[0111] By configuring the optical functional layer 12 (12b) to have a region in which the optical axis of the liquid crystal compound is twisted in the thickness direction, it is possible to increase the light diffraction efficiency.

[0112] In the above-described example, the optically functional layer 12 (12b) is a transmissive liquid crystal lens or a transmissive liquid crystal diffraction element that transmits light, but is not limited thereto. The optically functional layer may be a cholesteric liquid crystal layer having a helical structure in which the optical axis of the liquid crystal compound is twisted in the thickness direction.

[0113] Another example of an optically functional layer is conceptually shown in Figure 8. The optically functional layer 12c shown in Figure 8 is a cholesteric liquid crystal layer in which the optical axis of the liquid crystal compound is twisted in the thickness direction. The optically functional layer 12c has a liquid crystal orientation pattern in which the orientation of the optical axis derived from the liquid crystal compound changes while continuously rotating along at least one direction in the plane. The liquid crystal orientation pattern of the optically functional layer 12c may be the concentric liquid crystal orientation pattern shown in Figure 5 described above, or may be the liquid crystal orientation pattern shown in Figure 7 in which the orientation of the optical axis derived from the liquid crystal compound changes while continuously rotating along one direction.

[0114] The optically functional layer 12c, which is a cholesteric liquid crystal layer, has a helical structure in which liquid crystal compounds 40 are spirally wound and stacked, similar to a cholesteric liquid crystal layer formed by fixing a normal cholesteric liquid crystal phase, and has a structure in which liquid crystal compounds 40 spirally wound are stacked at multiple pitches, with one helical pitch being defined as a configuration in which liquid crystal compounds 40 are spirally wound and stacked one turn (360° rotation).

[0115] As is well known, a cholesteric liquid crystal layer has wavelength-selective reflectivity. For example, if the cholesteric liquid crystal layer has a selective reflection center wavelength in the green wavelength region, it reflects right-handed circularly polarized light of green light and transmits other light.

[0116] Here, when the optically functional layer 12c has a liquid crystal orientation pattern in which the liquid crystal compound 40 is rotated and oriented along one direction in the plane direction as in the example shown in Figure 7, the incident circularly polarized light is refracted (diffracted) and reflected in a direction in which the direction of the optical axis is continuously rotating. At this time, the direction of diffraction (azimuth direction) differs depending on the rotation direction of the incident circularly polarized light. That is, the optically functional layer 12c reflects right-handed or left-handed circularly polarized light of the selective reflection wavelength and diffracts this reflected light.

[0117] 5, the optical functional layer 12c reflects incident circularly polarized light by focusing or diverging it, depending on the rotation direction of the incident circularly polarized light. That is, the optical functional layer 12c reflects right-handed or left-handed circularly polarized light of the selective reflection wavelength and focuses or diverges this reflected light.

[0118] The optically functional layers 12, 12b, and 12c can be formed by fixing a liquid crystal phase oriented in a layer form in a liquid crystal orientation pattern in which the direction of the optical axis derived from the liquid crystal compound changes while continuously rotating along at least one direction in the plane.

[0119] The structure in which the liquid crystal phase is fixed may be any structure in which the orientation of the liquid crystal compound in the liquid crystal phase is maintained. Typically, a preferred structure is one in which the polymerizable liquid crystal compound is oriented along the liquid crystal orientation pattern, and then polymerized and hardened by ultraviolet irradiation, heating, etc. to form a non-fluid layer, and at the same time, the structure is changed to a state in which the orientation form does not change due to an external field or external force.

[0120] In the structure in which the liquid crystal phase is fixed, it is sufficient that the optical properties of the liquid crystal phase are maintained, and the liquid crystal compound in the optically functional layer does not need to exhibit liquid crystallinity. For example, a polymerizable liquid crystal compound may be polymerized by a curing reaction and lose its liquid crystallinity.

[0121] An example of a material used to form an optically functional layer formed by fixing a liquid crystal phase is a liquid crystal composition containing a liquid crystal compound. The liquid crystal compound is preferably a polymerizable liquid crystal compound. The liquid crystal composition used to form the optically functional layer may further contain a surfactant, a polymerization initiator, etc. Furthermore, when the liquid crystal compound is twistedly aligned in the thickness direction of the optically functional layer, or when the optically functional layer is a cholesteric liquid crystal layer, the liquid crystal composition may contain a chiral agent.

[0122] --Polymerizable Liquid Crystal Compound-- The polymerizable liquid crystal compound may be either a rod-shaped liquid crystal compound or a discotic liquid crystal compound.

[0123] Examples of rod-shaped polymerizable liquid crystal compounds that form the optically functional layer include rod-shaped nematic liquid crystal compounds. As rod-shaped nematic liquid crystal compounds, azomethines, azoxy compounds, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines, phenyldioxanes, tolanes, and alkenylcyclohexylbenzonitriles are preferably used. Not only low-molecular-weight liquid crystal compounds but also high-molecular-weight liquid crystal compounds can be used.

[0124] A polymerizable liquid crystal compound can be obtained by introducing a polymerizable group into a liquid crystal compound. Examples of the polymerizable group include an unsaturated polymerizable group, an epoxy group, and an aziridinyl group, with an unsaturated polymerizable group being preferred and an ethylenically unsaturated polymerizable group being more preferred. The polymerizable group can be introduced into the molecule of the liquid crystal compound by various methods. The number of polymerizable groups in the polymerizable liquid crystal compound is preferably 1 to 6, more preferably 1 to 3.

[0125] Examples of polymerizable liquid crystal compounds are described in Makromol. Chem. , Vol. 190, p. 2255 (1989), Advanced Materials Vol. 5, p. 107 (1993), U.S. Pat. No. 4,683,327, U.S. Pat. No. 5,622,648, U.S. Pat. No. 5,770,107, WO 95 / 22586, WO 95 / 24455, WO 97 / 00600, WO 98 / 23580, WO 98 / 52905, JP-A Nos. 1-272551, 6-016616, 7-110469, 11-080081, and 2001-328973. Two or more polymerizable liquid crystal compounds may be used in combination. When two or more types of polymerizable liquid crystal compounds are used in combination, the alignment temperature can be lowered.

[0126] Other examples of 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. Examples of the polymeric liquid crystal compounds that can be used include polymers having mesogen 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.

[0127] --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.

[0128] The amount of the polymerizable liquid crystal compound added in 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 content mass (mass excluding the solvent) of the liquid crystal composition.

[0129] --Chiral Agents (Optically Active Compounds)--Chiral agents have the function of inducing a helical structure in a liquid crystal phase. Since the direction of the helical twist and the helical twisting power (HTP) induced by each chiral agent vary depending on the compound, the chiral agent can be selected according to the purpose.

[0130] The chiral agent is not particularly limited, and known compounds (for example, those described in Liquid Crystal Device Handbook, Chapter 3, Section 4-3, Chiral Agents for TN (Twisted Nematic) and STN (Super Twisted Nematic), p. 199, edited by the 142nd Committee of the Japan Society for the Promotion of Science, 1989), isosorbide, isomannide derivatives, and the like can be used.

[0131] Chiral agents generally contain an asymmetric carbon atom, but axially asymmetric or planarly asymmetric compounds without an asymmetric carbon atom can also be used as chiral agents. Examples of axially asymmetric or planarly asymmetric compounds include binaphthyl, helicene, paracyclophane, and derivatives thereof. The chiral agent may have a polymerizable group. When both the chiral agent and the liquid crystal compound have a polymerizable group, a polymer having a repeating unit derived from the polymerizable liquid crystal compound and a repeating unit derived from the chiral agent can be formed by polymerization of the polymerizable chiral agent and the polymerizable liquid crystal compound. In this embodiment, the polymerizable group of the polymerizable chiral agent is preferably the same type of group as the polymerizable group of the polymerizable liquid crystal compound. Therefore, the polymerizable group of the chiral agent is preferably an unsaturated polymerizable group, an epoxy group, or an aziridinyl group, more preferably an unsaturated polymerizable group, and even more preferably an ethylenically unsaturated polymerizable group. The chiral agent may also be a liquid crystal compound.

[0132] When the chiral agent has a photoisomerizable group, it is possible to form a desired twisted alignment corresponding to the emission wavelength by irradiating the chiral agent with actinic rays or the like through a photomask after coating and alignment. The photoisomerizable group is preferably an isomerization site of a compound exhibiting photochromic properties, an azo group, an azoxy group, or a cinnamoyl group. Specific compounds that can be used include those described in JP-A-2002-080478, JP-A-2002-080851, JP-A-2002-179668, JP-A-2002-179669, JP-A-2002-179670, JP-A-2002-179681, JP-A-2002-179682, JP-A-2002-338575, JP-A-2002-338668, JP-A-2003-313189, and JP-A-2003-313292.

[0133] The content of the chiral dopant in the liquid crystal composition is preferably 0.01 to 200 mol %, more preferably 1 to 30 mol %, based on the molar amount of the liquid crystal compound.

[0134] [End Surface Covering Layer] The end surface covering layer 20 covers the end surfaces of the first laminate 14 at the interface between the support 18 and the optical functional layer 12 (12b, 12c).

[0135] The material forming the end surface covering layer 20 may be an organic material (organic substance) or an inorganic material (inorganic substance). Examples of organic materials include resins such as acrylic resin, epoxy resin, silicone resin, and urethane. Among these, from the viewpoint of preventing the corners of the optical functional layer 12 from peeling off from the support 18, it is preferable that the material forming the end surface covering layer 20 contains any of acrylic resin, epoxy resin, and silicone resin.

[0136] Inorganic materials for forming the end surface covering layer 20 include metals such as aluminum, chromium, and nickel, silicon nitride, silicon oxide, and aluminum oxide.

[0137] When the end face covering layer 20 is made of an organic material, it preferably contains a light-absorbing material, which can prevent light incident on the optical stack from being reflected by the end face covering layer 20 and becoming unnecessary noise light.

[0138] The light-absorbing material is not limited, and known light-absorbing materials can be used depending on the wavelength range to be absorbed. For example, when absorbing visible light, known light absorbers such as inorganic pigments, organic pigments such as insoluble azo pigments, and dyes such as azo and anthraquinone can be used. Inorganic pigments are composite oxide pigments, such as cobalt green (TiO2·CoO·NiO·ZrO2 or CoO·Cr2O3·TiO2·Al2O3) for green, cobalt blue (CoO·Al2O3) for blue, and iron oxide (Fe2O3) for red. Examples of materials that absorb blue-green include lead molybdate, lead chromate, and their blends. The light-absorbing material may also be configured to contain two or more light-absorbing materials that absorb light in different wavelength ranges.

[0139] When the end face covering layer 20 is an organic material, there are no particular limitations on the method for forming the end face covering layer 20. For example, a method can be used in which a coating liquid that will become the end face covering layer 20 is applied to the end face of the first laminate using a dispenser. In this case, by using a dispenser with a precision position adjustment mechanism, the end face of the first laminate can be accurately coated. In addition, the coverage area of ​​the end face, the width of the coating liquid that rides over the main surface, etc. can be adjusted by adjusting the dispenser's discharge position using the precision position adjustment mechanism. In addition, the thickness of the end face covering layer 20 can be adjusted by the amount of liquid discharged from the dispenser.

[0140] The coating film applied to the end face of the first laminate 14 may be subjected to a drying process, a curing process, etc. as needed. The curing method may be a known method such as heat curing or ultraviolet curing depending on the forming material.

[0141] When the end face covering layer 20 is an inorganic material, there are no particular limitations on the method for forming the end face covering layer 20, and the end face covering layer 20 may be formed by a known forming method depending on the type of inorganic material. For example, the end face covering layer 20 may be formed by masking the areas where the end face covering layer 20 is not to be formed, and by a known film forming method such as vapor deposition, sputtering, or plasma CVD (Chemical Vapor Deposition).

[0142] Next, an example of a method for producing an optical laminate will be described with reference to Fig. 9. In the example shown in Fig. 9, the optical laminate is formed by laminating an optical functional layer having a region that exhibits the function of a liquid crystal lens (liquid crystal diffractive lens) on a support.

[0143] First, as shown in the upper left of Fig. 9, a coating liquid that will become the alignment film 105 is applied to a substrate 104 to form a coating film. Next, the coating film is exposed to light to form an alignment pattern that corresponds to the liquid crystal alignment pattern of the optically functional layer (upper right of Fig. 9). In the illustrated example, four regions of one coating film are exposed to light to form four alignment patterns.

[0144] Figure 10 conceptually shows an example of an exposure device that exposes a coating film that will become the alignment film 105 (photo-alignment film) for forming the optical functional layer 12, and forms an alignment pattern that corresponds to a concentric liquid crystal alignment pattern in which the optical axis continuously rotates radially and changes.

[0145] The exposure device 80 shown in Figure 10 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 quarter-wave plate 96.

[0146] 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.

[0147] The P-polarized light MP and the S-polarized light MS are combined by the beam splitter 94, and are converted into right-handed circularly polarized light and left-handed circularly polarized light according to the polarization direction by the quarter-wave plate 96, and are incident on the coating film (alignment film 105) on the substrate 104.

[0148] Here, due to interference between the right-handed and left-handed circularly polarized light, the polarization state of the light irradiated onto the alignment film 105 changes periodically in the form of interference fringes. As the crossing angle between the left-handed and right-handed circularly polarized light changes from the inside to the outside of the concentric circles, an exposure pattern is obtained in which the pitch (one period) gradually shortens from the inside to the outside. As a result, a concentric (radial) alignment pattern in which the alignment state changes periodically is obtained on the alignment film 105.

[0149] In this exposure device 80, one period Λ of the liquid crystal orientation pattern in which the optical axis of the liquid crystal compound 40 continuously rotates 180° along one direction can be controlled by changing the refractive power of the lens 92, the focal length of the lens 92, and the distance between the lens 92 and the orientation film 105, etc.

[0150] Furthermore, by adjusting the refractive power of the lens 92 (the F-number of the lens 92), the length of one period of the liquid crystal alignment pattern can be changed in one direction in which the optical axis rotates continuously.

[0151] Specifically, the length of one period of the liquid crystal orientation pattern can be changed in one direction in which the optical axis continuously rotates, depending on the spread angle of the light expanded by the lens 92 that interferes with the parallel light. More specifically, when the refractive power of the lens 92 is weakened, the light approaches parallel light, and the length Λ of one period of the liquid crystal orientation pattern gradually shortens from the inside to the outside. Conversely, when the refractive power of the lens 92 is strengthened, the length Λ of one period of the liquid crystal orientation pattern suddenly shortens from the inside to the outside.

[0152] That is, by adjusting the refractive index of the lens 92, it is possible to adjust the refractive index of the liquid crystal lens (optical functional layer 12) which acts as a concave lens or a convex lens depending on the rotation direction of the incident circularly polarized light.

[0153] Next, a liquid crystal composition containing a liquid crystal compound for forming the optically functional layer 12 described above is applied onto the exposed alignment film 105, dried, and further hardened by ultraviolet irradiation, etc., as necessary, to form a liquid crystal layer 102 having a plurality of regions with concentric liquid crystal alignment patterns, as shown in the left side of the middle section of Figure 9.

[0154] 9, four liquid crystal lenses are formed in the liquid crystal layer 102. As described above, each of these liquid crystal lenses has a concentric liquid crystal orientation pattern in which the optical axis derived from the liquid crystal compound continuously rotates in one direction.

[0155] Next, as shown on the right side of the middle row of FIG. 9, the liquid crystal layer 102 is cut out into regions each having a liquid crystal orientation pattern.

[0156] The cutting method is not particularly limited, and any conventionally known cutting method such as dicing, laser processing, punching, etc. can be used.

[0157] As a result of the above, a first laminate 14 is obtained in which the optically functional layer 12 is laminated on the support 18, as shown in the lower right side of Fig. 9. That is, in this example, the support 18 has a base material and an alignment film. Because the first laminate 14 has been cut, the end face of the support 18 and the end face of the optically functional layer 12 are flush with each other.

[0158] Next, the end surface covering layer 20 is formed on the end surface of each of the obtained first laminates 14. The method for forming the end surface covering layer 20 is as described above.

[0159] In this manner, the optical laminate 10 of the present invention is obtained.

[0160] 9, four regions including liquid crystal orientation patterns are formed in one liquid crystal layer 102, but this is not limited to this, and the liquid crystal layer 102 may be formed with one to three regions including liquid crystal orientation patterns, or may be formed with five or more regions including liquid crystal orientation patterns. Furthermore, the arrangement of the liquid crystal orientation patterns in the liquid crystal layer 102 is not limited to the illustrated example.

[0161] In the above example, the alignment film 105 is formed on the substrate 104, and then the liquid crystal layer 102 is formed, and then the liquid crystal layer 102 is cut together with the substrate 104 and the alignment film 105. However, this is not limiting. After the alignment film 105 is formed on the substrate 104 and then the liquid crystal layer 102 is formed, the liquid crystal layer 102 may be peeled from the substrate 104 and attached to another support, and then the liquid crystal layer may be cut together with this other support to produce the first laminate 14. In this case, only the liquid crystal layer 102 may be transferred to another support, or the alignment film may be peeled from the substrate 104 together with the liquid crystal layer 102, and then the laminate of the alignment film 105 and the liquid crystal layer 102 may be transferred to another support.

[0162] When transferring the liquid crystal layer 102 to another support, an optical adhesive such as OCA (Optically Clear Adhesive) may be used as needed.

[0163] In addition, in the example shown in Figure 9, a concentric liquid crystal orientation pattern is formed in the liquid crystal layer 102, but this is not limited to this, and the liquid crystal layer 102 may be formed with multiple liquid crystal orientation patterns, each having a direction in which the orientation of the optical axis 40A of the liquid crystal compound 40 rotates and changes in one direction, as shown in Figure 7.

[0164] FIG. 11 conceptually shows an example of an exposure apparatus for exposing an alignment film for forming an optically functional layer having a liquid crystal alignment pattern as shown in FIG.

[0165] The exposure device 60 shown in Figure 11 includes a light source 64 equipped with a laser 62, a λ / 2 plate 65 that changes the polarization direction of laser light M emitted by the laser 62, a beam splitter 68 that splits the laser light M emitted by the laser 62 into two light rays MA and MB, mirrors 70A and 70B that are arranged on the optical paths of the two split light rays MA and MB, respectively, and λ / 4 plates 72A and 72B.

[0166] The light source 64 emits linearly polarized light P0. The λ / 4 plate 72A converts the linearly polarized light P0 (light beam MA) into right-handed circularly polarized light P R The λ / 4 plate 72B converts the linearly polarized light P0 (light beam MB) into left-handed circularly polarized light P L are converted to , respectively.

[0167] A substrate 104 having an alignment film 105 (a coating film that will become an alignment film) before an alignment pattern is formed is placed in an exposure section, and two light beams MA and MB are made to intersect and interfere on the alignment film 105, and the alignment film 105 is exposed by being irradiated with the interference light.

[0168] The interference at this time causes the polarization state of the light irradiated onto the alignment film 105 to periodically change in the form of interference fringes, thereby obtaining an alignment film having an alignment pattern in which the alignment state periodically changes (hereinafter also referred to as a pattern alignment film).

[0169] In the exposure device 60, the period of the orientation pattern can be adjusted by changing the crossing angle α of the two light beams MA and MB. That is, in the exposure device 60, by adjusting the crossing angle α, in the orientation pattern in which the optical axis 40A derived from the liquid crystal compound 40 continuously rotates along one direction, the length of one period in which the optical axis 40A rotates by 180° in one direction in which the optical axis 40A rotates can be adjusted.

[0170] By forming a liquid crystal layer on an alignment film 105 having an alignment pattern in which the alignment state changes periodically, an optically anisotropic layer can be formed having a liquid crystal alignment pattern in which the optical axis 40A derived from the liquid crystal compound 40 rotates continuously along one direction.

[0171] Furthermore, by rotating the optical axes of the λ / 4 plates 72A and 72B by 90°, the rotation direction of the optical axis 40A can be reversed.

[0172] The optical laminate of the present invention has been described above, but the present invention is not limited thereto, and various improvements and modifications may be made within the scope of the present invention.

[0173] The present invention will be described in more detail below with reference to specific examples of the present invention.

[0174] [Example 1] A glass substrate having a size of 150 mm x 150 mm and a thickness of 0.5 mm was used as the substrate, and the following coating liquid for forming an alignment film was applied by spin coating. The substrate on which the coating liquid for forming an alignment film had been formed was dried on a hot plate at 60°C for 60 seconds to form an alignment film.

[0175] 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 ---------------------------------------------------

[0176] -Photo alignment material A-

[0177] (Exposure of alignment film) The formed alignment film was exposed using the beam combiner (exposure device) of Example 1 of WO 2022 / 016539, and an alignment film P-1 having an alignment pattern capable of forming a liquid crystal alignment pattern having a radial direction in which the optical axis 40A of the liquid crystal compound 40 changes while continuously rotating, as shown in FIG.

[0178] The period Λ of the alignment pattern of the alignment film varies within the plane, but its minimum value was set to 1 μm. The period Λ of the alignment pattern was adjusted by the focal length of a convex lens used as an optical element.

[0179] The light source used was one that emitted laser light with a wavelength of 355 nm. The exposure dose by the interference light was 1000 mJ / cm. 2 It was decided.

[0180] In this example, the alignment film was exposed to light in four places, that is, four regions having alignment patterns were formed on the alignment film.

[0181] The thermal expansion coefficient of the support having the glass substrate and the alignment film is 3×10 -6 / ℃.

[0182] (Formation of Liquid Crystal Layer) The following liquid crystal composition A-1 was prepared as a liquid crystal composition for forming a liquid crystal layer A-1 including a region that would become an optically functional layer.

[0183] Liquid crystal composition A-1 ----------------------------------- Liquid crystal compound L-1 100.00 parts by mass Polymerization initiator (Irgacure OXE01, manufactured by BASF) 1.00 part by mass Leveling agent T-1 0.08 part by mass Methyl ethyl ketone 1050.00 parts by mass ---------------------------------------------------

[0184] Liquid crystal compound L-1

[0185] Leveling agent T-1

[0186] The liquid crystal composition A-1 was applied onto the alignment film P-1, and the coating was heated on a hot plate to 80° C. Thereafter, ultraviolet light having a wavelength of 365 nm was applied at 300 mJ / cm using a high-pressure mercury lamp under a nitrogen atmosphere. 2 The alignment of the liquid crystal compound was fixed by irradiating the coating film with an irradiation amount of 1000 .mu.m / s. As a result, four regions having a concentric liquid crystal alignment pattern were formed in the liquid crystal layer A-1.

[0187] In this way, a laminate was obtained in which the alignment film P-1 and the liquid crystal layer A-1 were laminated in this order on the glass substrate.

[0188] Next, regions containing liquid crystal alignment patterns were cut out from this laminate by dicing to obtain first laminates each having a size of 4 cm x 4 cm, with the center of the cut first laminate being aligned approximately with the center of the liquid crystal alignment pattern.

[0189] The acrylic resin coating solution for the end surface coating layer was prepared by mixing A-DPH manufactured by Shin-Nakamura Chemical Co., Ltd., KBM-5103 (a silane coupling agent manufactured by Shin-Etsu Silicones Co., Ltd.), a polymerization initiator (Irg184 manufactured by BASF), and a solvent (methyl ethyl ketone (MEK)). The acrylic resin coating solution was applied to the end surface of the obtained first laminate using a dispenser (SDP520 manufactured by San-Ei Tech Co., Ltd.) equipped with a precision position adjustment mechanism (AXA200 manufactured by San-Ei Tech Co., Ltd.), followed by heating (100°C, 1 min) and UV irradiation (365 nm, 300 mJ / cm). 2 ) to form an edge coating layer. The edge coating layer had a thickness d of 1 μm and was not formed on the main surface of the first laminate. In other words, it had no elevated portion. Furthermore, when viewed from a direction perpendicular to the main surface of the first laminate, the edge coating layer was provided at both ends of each side of the main surface of the first laminate, and was formed so that the length from each corner was 15% of the side length L. That is, on each side of the main surface of the first laminate, the total length of the edge coating layer was 30% of the side length. Furthermore, the length of the edge coating layer in the thickness direction was 50% of the thickness of the first laminate. In this manner, an optical laminate was fabricated. Note that in each of the following examples and comparative examples, the coverage area of ​​the edge coating layer, the elevation width on the main surface, etc. were changed by adjusting the dispenser's discharge position using a position adjustment mechanism. Furthermore, the thickness of the edge coating layer was changed by changing the dispenser's discharge amount.

[0190] The peel strength of the edge covering layer from the support and the optically functional layer was evaluated by attaching a piece of Cellotape (registered trademark) with a peel strength of 4 N / cm to the edge covering layer, and then pulling the tape in a 90° direction using a peel tester, and determining whether the edge covering layer was transferred to the tape. The peel strength was 4 N / cm or more.

[0191] [Example 2] An optical laminate was produced in the same manner as in Example 1, except that the length of each of the end surface covering layers from the corners of the main surface of the first laminate, when viewed from a direction perpendicular to the main surface of the first laminate, was formed to be 25% of the side length L.

[0192] [Example 3] An optical laminate was produced in the same manner as in Example 1, except that, when viewed from a direction perpendicular to the main surface of the first laminate, the end surface covering layer was formed over the entire area of ​​each side of the main surface of the first laminate.

[0193] Example 4 An optical laminate was produced in the same manner as in Example 2, except that the thickness d of the end surface covering layer was set to 0.5 μm.

[0194] Example 5 An optical laminate was produced in the same manner as in Example 2, except that the end surface covering layer had a rising portion formed on the main surface on the optical functional layer side.

[0195] The width w of the rising portion was set to 0.1 mm, and the height h was set to 1 μm.

[0196] Example 6 An optical laminate was produced in the same manner as in Example 2, except that the end surface covering layer had a rising portion formed on both main surfaces of the first laminate.

[0197] The width w of the rising portion was set to 0.1 mm, and the height h was set to 1 μm.

[0198] [Example 7] An optical laminate was prepared in the same manner as in Example 5, except that the amount of silane coupling agent added was reduced so that the peel strength of the end surface coating layer from the support and the optically functional layer was less than 4 N / cm.

[0199] Example 8 An optical laminate was produced in the same manner as in Example 6, except that the material for forming the end surface covering layer was changed to an epoxy resin (EPICLON manufactured by DIC Corporation).

[0200] Example 9 An optical laminate was produced in the same manner as in Example 6, except that the material for forming the end face coating layer was changed to a silicone resin (X-88-2003A manufactured by Shin-Etsu Silicones Co., Ltd.) In this example, the end face coating layer was cured by placing it in a 25°C atmosphere for 30 minutes without heating or UV irradiation.

[0201] Example 10 An optical laminate was produced in the same manner as in Example 5, except that a light-absorbing material was added to the coating liquid for the end face covering layer.

[0202] As the light absorbing material, synthetic dye black (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was used. The ratio of the light absorbing material to the coating liquid was 0.02% by mass.

[0203] [Example 11] An optical laminate was produced in the same manner as in Example 2, except that an aluminum film was formed as the end surface covering layer by vapor deposition to a thickness d of 10 nm. The position where the end surface covering layer was formed was adjusted by masking with polyimide tape.

[0204] Example 12 An optical laminate was produced in the same manner as in Example 11, except that the thickness d of the end surface covering layer was set to 5 nm.

[0205] [Example 13] An optical laminate was produced in the same manner as in Example 5, except that a silicon substrate having a size of 150 mm x 150 mm and a thickness of 0.5 mm was used as the substrate, and a laminate in which an optical functional layer was laminated on the silicon substrate was cut to 40 mm x 40 mm to produce a first laminate. The thermal expansion coefficient of the support was 4 x 10 -6 / ℃.

[0206] [Example 14] An optical laminate was produced in the same manner as in Example 5, except that a quartz substrate having a size of 150 mm × 150 mm and a thickness of 0.5 mm was used as the substrate, and a laminate in which an optical functional layer was laminated on the quartz substrate was cut to 40 mm × 40 mm to produce a first laminate. The thermal expansion coefficient of the support was 5 × 10 -7 / ℃.

[0207] Comparative Example 1 An optical laminate was produced in the same manner as in Example 1, except that the end surface covering layer was not formed.

[0208] [Comparative Example 2] An optical laminate was produced in the same manner as in Example 1, except that the length of each of the end surface covering layers from the corners of the main surface of the first laminate, when viewed from a direction perpendicular to the main surface of the first laminate, was formed to be 5% of the side length L.

[0209] [Evaluation A] The optical laminates of the examples and comparative examples were stored in a room at room temperature (25°C) for one day, and then the side surfaces of the optical laminates were observed under a microscope to determine whether or not the optical functional layer had peeled off from the support. If there was no peeling, it was evaluated as A, and if there was peeling, it was evaluated as C.

[0210] [Evaluation B] After storing the prepared optical laminates of Examples and Comparative Examples in a low-temperature dryer set at 50° C. for 1 day and for 7 days, the side surfaces of the optical laminates were observed under a microscope to determine whether or not the optical functional layer had peeled from the support. A was evaluated for cases where there was no peeling after 7 days, B for cases where there was no peeling after 1 day but there was peeling after 7 days, and C for cases where there was peeling after 1 day.

[0211] The results are shown in Table 1. In Table 1, the peel force was expressed as A when it was 4 N / cm or more, and as B when it was less than 4 N / cm.

[0212]

[0213] From Table 1, it can be seen that the Examples of the present invention can suppress peeling of the optically functional layer from the support, compared to the Comparative Examples.

[0214] Furthermore, by comparing Examples 1 to 3, it can be seen that the total length of the end surface covering layer when viewed from a direction perpendicular to the main surface of the first laminate is preferably 50% or more of the length of each side of the main surface of the first laminate.

[0215] Comparing Example 2 with Example 4, it is clear that when the end face covering layer is made of an organic material, the thickness d of the end face covering layer is preferably 1 μm or more.

[0216] A comparison of Examples 2, 5, and 6 reveals that it is preferable for the end surface covering layer to have a rising portion formed on the main surface of the first laminate.

[0217] Comparing Example 5 with Example 7, it is clear that the peel strength of the end surface covering layer between the support and the optically functional layer is preferably 4 N / cm or more.

[0218] Light was irradiated from a light source onto the optical laminate of Example 10, and the amount of properly diffracted light (first-order diffracted light) that passed through the optical laminate and the amount of light that was not properly diffracted (zeroth-order light and -first-order light) were measured using an optical power meter. It was confirmed that the inclusion of a light-absorbing material in the end face covering layer made it possible to suppress unnecessary noise light (zeroth-order light and -first-order light).

[0219] A comparison between Example 11 and Example 12 reveals that when the end face covering layer is made of an inorganic material, the thickness d of the end face covering layer is preferably 10 nm or more.

[0220] The above results clearly demonstrate the effectiveness of the present invention.

[0221] 10, 10b, 10c Optical laminate 12 Optical functional layer 14 First laminate 18 Support 20, 20b, 20c End surface covering layer 40 Liquid crystal compound 40A Optical axis 60, 80 Exposure device 62, 82 Laser 64, 84 Light source 65 λ / 2 plate 68 Beam splitter 70A, 70B Mirror 72A, 72B λ / 4 plate 86, 94 Polarizing beam splitter 90A, 90B Lens 92 Lens 96 λ / 4 plate 102 Liquid crystal layer 104 Substrate 105 Alignment film

Claims

1. A first laminate having a support and an optically functional layer laminated on the support and formed using a liquid crystal composition containing a liquid crystal compound, wherein the thermal expansion coefficient of the support is 1×10 -5 / °C or less, the optical functional layer has a liquid crystal orientation pattern in which the orientation of the optical axis derived from the liquid crystal compound changes while rotating continuously along at least one direction in a plane, an end face of the support in the first laminate and an end face of the optical functional layer are flush with each other, the first laminate has an end face covering layer covering an interface between the support and the optical functional layer on the end face of the first laminate, and when viewed in a direction perpendicular to the main surface of the first laminate, the end face covering layer covers an area of ​​10% or more of the length of each side from each corner of the main surface of the first laminate.

2. The optical laminate described in claim 1, wherein, when viewed from a direction perpendicular to the main surface of the first laminate, the end surface covering layer covers an area of ​​50% or more of the length of each side of the main surface of the first laminate.

3. The optical laminate according to claim 1 or 2, wherein the end surface covering layer is made of an organic material and has a thickness of 1 μm to 1 mm in a direction perpendicular to the end surface of the first laminate.

4. The optical laminate according to claim 1 or 2, wherein the end surface covering layer is made of an inorganic material and has a thickness of 10 nm to 500 nm in a direction perpendicular to the end surface of the first laminate.

5. The optical laminate according to claim 1, wherein the end surface covering layer covers a portion of at least one of the main surfaces of the first laminate to an end surface.

6. The optical laminate according to claim 5, wherein the end surface covering layer covers the end surfaces of the first laminate from a portion of the main surface on the optically functional layer side.

7. The optical laminate according to claim 5, wherein the end surface covering layer covers the end surfaces from a portion of the main surfaces on both sides of the first laminate.

8. An optical laminate according to any one of claims 5 to 7, wherein the width of the rising portion of the end surface covering layer formed on the main surface of the first laminate from the end surface is 0.01 mm or more.

9. The optical laminate according to any one of claims 5 to 7, wherein the end surface covering layer is an organic material, and the height of a rising portion formed on a principal surface of the first laminate in a direction perpendicular to the principal surface is 1 μm to 1 mm.

10. An optical laminate according to any one of claims 5 to 7, wherein the end surface covering layer is an inorganic material, and the height of a rising portion formed on a principal surface of the first laminate in a direction perpendicular to the principal surface is 10 nm to 500 nm.

11. The optical laminate according to claim 1 or 2, wherein the peel strength of the end surface covering layer between the support and the optically functional layer is 4 N / cm or more.

12. The optical laminate according to claim 1 or 2, wherein the material of the support includes any one of glass, quartz, and silicon.

13. The optical laminate according to claim 1 or 2, wherein the end surface covering layer is an organic material and contains any one of an acrylic resin, an epoxy resin, and a silicone resin.

14. The optical laminate according to claim 1 or 2, wherein the end surface covering layer is organic and contains a light absorbing material.

15. The optical laminate described in claim 1 or 2, wherein the optical functional layer is formed using a liquid crystal composition containing a polymerizable liquid crystal compound and is a cured film formed by polymerizing the polymerizable liquid crystal compound.

16. The optical laminate according to claim 1 or 2, wherein the first laminate is cut out.

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