Optical element, image display device, virtual reality display device, electronic viewfinder, and method for manufacturing polarizer

Abstract

To provide an optical element in which, when an absorption-type polarizer having a curved portion is applied to an image display device using a reciprocating optical system, the effect of suppressing ghosting is excellent. Also, to provide an image display device, a virtual reality display device, an electronic viewfinder, and a manufacturing method of a polarizer. The optical element of the present invention includes an absorption-type polarizer A and an absorption-type polarizer B having a curved portion, a position X is set to a position on a surface of the polarizer A on the polarizer B side closest to the polarizer B side, a position Y is set to a position on a surface of the polarizer B on the polarizer A side closest to the position X, in the case where a straight line L passing through the position X and the position Y is drawn, when the position X is observed on the straight line L and from the position Y, there is a position Z that satisfies a certain requirement at a position on the opposite side from the position X.

Description

Technical Field

[0001] This invention relates to a method for manufacturing an optical element, an image display device, a virtual reality display device, an electronic viewfinder, and a polarizer. Background Technology

[0002] Absorption polarizers are widely used in image display devices such as liquid crystal displays and organic EL displays. However, the orientation of the in-plane absorption axis of these polarizers is mostly the same (a straight line).

[0003] On the other hand, in recent years, in image display devices such as virtual reality display devices and electronic viewfinders, in order to make the display unit smaller and thinner, image display devices using a reciprocating optical system as described in Patent Document 1 have been proposed. In these virtual image display devices, in order to suppress unwanted images such as ghosting caused by stray light (hereinafter also simply referred to as "ghosting"), an absorptive polarizer is used on the visual recognition side. However, in this case, depending on the shape of the lens, it is preferable that the aforementioned polarizer also has a curved surface.

[0004] Previous technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 7-120679 Summary of the Invention

[0007] The technical problem to be solved by the invention

[0008] According to the inventors' research, it has been found that in image display devices using reciprocating optical systems, even when an absorptive polarizer with a curved surface is provided on the visual recognition side, stray light cannot be sufficiently suppressed, and ghosting may sometimes occur.

[0009] The present invention was made in view of the above-mentioned problems. The object of the present invention is to provide an optical element that effectively suppresses ghosting when an absorptive polarizer with a curved surface is applied to an image display device using a reciprocating optical system. Furthermore, the object of the present invention is to provide an image display device, a virtual reality display device, an electronic viewfinder, and a method for manufacturing a polarizer.

[0010] means for solving technical problems

[0011] The inventors, through in-depth research on the above-mentioned issues, discovered that the following structure can solve these issues.

[0012] [1] An optical element comprising an absorptive polarizer A and an absorptive polarizer B having curved surfaces, wherein position X is defined as the position closest to polarizer B on the surface of polarizer A on polarizer B side, and position Y is defined as the position of the surface of polarizer B on polarizer A side closest to position X. When a straight line L is drawn through position X and position Y, a position Z satisfying a specific requirement exists on the straight line L and when position X is viewed from position Y, at a position further opposite to position X.

[0013] [2] According to the optical element described in [1], wherein,

[0014] Polarizer A has regions where the directions of the absorption axes are different from each other.

[0015] [3] The optical element according to [1] or [2], wherein,

[0016] Polarizer A has an anisotropic light-absorbing layer comprising a liquid crystal compound and a dichroic material.

[0017] [4] According to the optical element described in [3], wherein,

[0018] Polarizer A also has an optical alignment film.

[0019] [5] An image display device comprising an optical element and an image display element as described in any one of [1] to [4].

[0020] [6] The image display device according to [5], wherein,

[0021] Between polarizer A and polarizer B, starting from polarizer A, there are sequentially a reflective linear polarizer, a first λ / 4 plate, a half-reflective mirror, and a second λ / 4 plate. When viewed from the direction extending from the straight line L, the direction of the absorption axis of polarizer A at position X and the direction of the reflection axis of the reflective linear polarizer at the intersection of the straight line L and the reflective linear polarizer are parallel. When viewed from the direction extending from the virtual lines L1 to L4, the direction of the absorption axis of polarizer A at the intersection of the virtual lines L1 to L4 and polarizer A, and the direction of the reflection axis of the reflective linear polarizer at the intersection of the virtual lines L1 to L4 and the reflective linear polarizer are parallel.

[0022] [7] The image display device according to [6], wherein,

[0023] When viewed from the direction extending from line L, the angle between the direction of the absorption axis of polarizer A at position X and the direction of the slow axis of the first λ / 4 plate at the intersection of line L and the first λ / 4 plate is 45±10°. When viewed from the direction extending from virtual lines L1 to L4, the angle between the direction of the absorption axis of polarizer A at the intersection of virtual lines L1 to L4 and polarizer A and the direction of the slow axis of the first λ / 4 plate at the intersection of virtual lines L1 to L4 and the first λ / 4 plate is 45±10°.

[0024] [8] The image display device according to [6] or [7], wherein,

[0025] When viewed from the direction of the extension of line L, the direction of the slow axis of the first λ / 4 plate at the intersection of line L and the first λ / 4 plate, and the direction of the slow axis of the second λ / 4 plate at the intersection of line L and the second λ / 4 plate are orthogonal. When viewed from the direction of the extension of virtual lines L1 to L4, the direction of the slow axis of the first λ / 4 plate at the intersection of virtual lines L1 to L4 and the first λ / 4 plate, and the direction of the slow axis of the second λ / 4 plate at the intersection of virtual lines L1 to L4 and the second λ / 4 plate are orthogonal.

[0026] [9] The image display device according to [5], wherein,

[0027] Between polarizer A and polarizer B, starting from polarizer A, there are sequentially arranged a first λ / 4 plate, a reflecting circular polarizer, a half-reflecting mirror, and a second λ / 4 plate. When viewed from the direction extending from the straight line L, the angle between the direction of the absorption axis of polarizer A at position X and the direction of the slow axis of the first λ / 4 plate at the intersection of the straight line L and the first λ / 4 plate is 45±10°. When viewed from the direction extending from the virtual lines L1 to L4, the angle between the direction of the absorption axis of polarizer A at the intersection of the virtual lines L1 to L4 and polarizer A and the direction of the slow axis of the first λ / 4 plate at the intersection of the virtual lines L1 to L4 and the first λ / 4 plate is 45±10°.

[0028]

[10] The image display device according to [9], wherein,

[0029] The reflective circular polarizer has a cholesterol-type liquid crystal layer.

[0030]

[11] The image display device according to any one of [5] to

[10] , wherein,

[0031] Polarizer B is stacked on the image display element.

[0032]

[12] A virtual reality display device comprising the image display device described in any one of [5] to

[11] .

[0033]

[13] An electronic viewfinder comprising the image display device described in any one of [5] to

[11] .

[0034]

[14] A method for manufacturing a polarizer, the polarizer being an absorption type polarizer having multiple regions with absorption axes having different directions and having curved portions, the method comprising a step of spraying a composition comprising a liquid crystal compound and a dichroic substance onto the surface of an alignment film, wherein the alignment film has curved portions and multiple regions having orientation limiting forces having different directions.

[0035]

[15] The method for manufacturing a polarizer according to

[14] further includes the following steps:

[0036] After forming a layer of a composition for forming a photoalignment film containing a photoalignment agent on the surface of a resin substrate, the photoalignment agent is oriented by irradiating the layer with ultraviolet light of linearly polarized light through a lens, thereby forming an alignment film.

[0037] Invention Effects

[0038] According to the present invention, an optical element with excellent ghosting suppression effect can be provided when an absorption polarizer with a curved surface is applied to a virtual image display device using a reciprocating optical system. Furthermore, according to the present invention, an image display device, a virtual reality display device, an electronic viewfinder, and a method for manufacturing a polarizer can be provided. Attached Figure Description

[0039] Figure 1 This is a schematic diagram illustrating an example of the structure of the optical element involved in this invention.

[0040] Figure 2 This is a schematic diagram illustrating an example of the structure of an image display device using a conventional reciprocating optical system.

[0041] Figure 3 This is a schematic diagram showing the direction of the absorption axis of absorption polarizer A.

[0042] Figure 4 This is a schematic diagram illustrating the structure of the image display device according to the first embodiment of the present invention.

[0043] Figure 5 This is a schematic diagram illustrating the structure of the image display device according to the second embodiment of the present invention. Detailed Implementation

[0044] The present invention will now be described in detail with reference to the accompanying drawings. The description of the constituent elements described below is sometimes based on representative embodiments and specific examples, but the present invention is not limited to such embodiments.

[0045] In this specification, the numerical range indicated by “~” represents the range included by the values ​​recorded before and after “~” as the lower and upper limits.

[0046] In this specification, "orthogonal" does not mean 90° in the strict sense, but rather 90° ± 10°, preferably 90° ± 5°. Similarly, "parallel" does not mean 0° in the strict sense, but rather 0° ± 10°, preferably 0° ± 5°. Furthermore, "45°" does not mean 45° in the strict sense, but rather 45° ± 10°, preferably 45° ± 5°.

[0047] In this specification, "absorption axis" refers to the direction of maximum in-plane absorbance. "Reflection axis" refers to the direction of maximum in-plane reflectivity. Furthermore, "slow axis" refers to the direction of maximum in-plane refractive index.

[0048] In this specification, when referred to as "local absorption axis" or similar terms, "local" refers to the orientation of the local absorption axis at a point of interest, rather than the orientation of the average absorption axis over the entire area of ​​the thin film.

[0049] [Optical Components]

[0050] The optical element involved in this invention (hereinafter also referred to as "this optical element") is an optical element that includes an absorptive polarizer A and an absorptive polarizer B having curved surfaces, and has a position Z that satisfies the requirements described later on a straight line L connecting a specific position X of polarizer A and a specific position Y of polarizer B.

[0051] Figure 1 The image shows an example of the structure of the optical element involved in this invention.

[0052] Figure 1 The optical element 10 shown has polarizer A100 and polarizer B400. Polarizer A100 is an absorption polarizer with a curved surface, and polarizer B400 is a planar absorption polarizer.

[0053] like Figure 1 As shown, in optical element 10, position X is defined as the position closest to polarizer B on the surface of polarizer A on the polarizer B side, and position Y is defined as the position of the surface of polarizer B on the polarizer A side closest to position X. When a straight line L is drawn through position X and position Y, on the straight line L and when position X is viewed from position Y, there exists a position Z that satisfies the following condition (hereinafter also referred to as "specific condition") at a position further opposite to position X.

[0054] (Specific requirements)

[0055] (a) There exist virtual lines L1, L2, L3 and L4 that pass through position Z and form an angle of 30° with line L.

[0056] (b) The angle between the line Lp1 projected onto polarizer B by the virtual line L1 and the line Lp2 projected onto polarizer B by the virtual line L2 is 90°. The angle between the line Lp2 and the line Lp3 projected onto polarizer B by the virtual line L3 is 90°. The angle between the line Lp3 and the line Lp4 projected onto polarizer B by the virtual line L4 is 90°. The angle between the line Lp4 and the line Lp1 is 90°.

[0057] (c) The angle between the straight line Lp1 and the absorption axis of the polarizer B is 45°.

[0058] (d) When viewed from the direction of the line L, the direction of the absorption axis of polarizer A at position X is orthogonal to the direction of the absorption axis of polarizer B at position Y.

[0059] (e) When viewed from the direction in which the virtual line L1 extends, the direction of the absorption axis of polarizer A at the intersection of the virtual line L1 and polarizer A is orthogonal to the direction of the absorption axis of polarizer B at the intersection of the virtual line L1 and polarizer B.

[0060] (f) When viewed from the direction in which the virtual line L2 extends, the direction of the absorption axis of polarizer A at the intersection of the virtual line L2 and polarizer A is orthogonal to the direction of the absorption axis of polarizer B at the intersection of the virtual line L2 and polarizer B.

[0061] (g) When viewed from the direction in which the virtual line L3 extends, the direction of the absorption axis of polarizer A at the intersection of the virtual line L3 and polarizer A is orthogonal to the direction of the absorption axis of polarizer B at the intersection of the virtual line L3 and polarizer B.

[0062] (h) When viewed from the direction in which the virtual line L4 extends, the direction of the absorption axis of polarizer A at the intersection of the virtual line L4 and polarizer A is orthogonal to the direction of the absorption axis of polarizer B at the intersection of the virtual line L4 and polarizer B.

[0063] As a result of in-depth research on the above-mentioned issues, the inventors discovered the following: In an optical element including an absorptive polarizer A and an absorptive polarizer B with curved surfaces, by adjusting the structures of polarizer A and polarizer B, a position Z that satisfies the above-mentioned specific requirements can be present. In particular, by determining the local orientation of the absorption axis of polarizer A, the effect of suppressing ghosting can also be improved in an image display device using an absorptive polarizer with curved surfaces.

[0064] The inventors investigated the reasons why, in image display devices using conventional reciprocating optical systems, an absorptive polarizer with a curved portion is not adequately suppressed on the visual recognition side, as follows.

[0065] The following explains the reasons mentioned above and the effects of the optical elements involved in this invention. Figure 2 This is a schematic diagram illustrating an example of the structure of an image display device using a conventional reciprocating optical system.

[0066] Figure 2 The conventional image display device 30 shown includes, sequentially from the observer's viewpoint O (visual recognition side), at least an absorptive polarizer 31 with a curved surface, a reflective polarizer 32, a semi-reflective mirror 33, an absorptive polarizer 34, and an image display element 35. Furthermore, the image display device 30 includes a phase retardation plate, such as a λ / 4 plate (not shown). When using the image display device 30, as... Figure 2 As shown, the light ray V emitted from the image display element 35 is reflected by the reflective polarizer 32 and the semi-reflective mirror 33, circling back and forth within the optical system. After passing through the reflective polarizer 32 and the absorptive polarizer 34, it is injected from the lens (not shown) on the visual recognition side. Thus, by circling back and forth with the light ray V, the optical distance can be extended, and it contributes to the miniaturization and thinning of the optical system. Therefore, conventional reciprocating optical systems are designed to appropriately reflect and polarize the light ray V.

[0067] However, according to the inventors' research, it has been found that most of the ghosting visually perceived in image display devices using reciprocating optical systems is not caused by the reciprocating rays V within the optical system, but by the non-reciprocating rays S that directly reach the observer's viewpoint O via the reflective polarizer 32 (see reference). Figure 2 This is caused by the fact that, in particular, when the polarization degree of the reflective polarizer 32 is insufficient, there is a tendency for the amount of light S transmitted without being reflected by the reflective polarizer 32 to increase. The transmission of light S can be suppressed by using an absorptive polarizer 31 disposed on the visual recognition side. However, it has been found that since the absorptive polarizer 31 has a curved surface, the local absorption axis of the absorptive polarizer 31 at the intersection of the line connecting the viewpoint O and the absorptive polarizer 34 and the absorptive polarizer 31, and the local absorption axis of the absorptive polarizer 34 at the intersection of the absorptive polarizer 34 and the aforementioned line are not strictly orthogonal. As a result, the light S cannot be sufficiently blocked, and thus, ghosting is sometimes not sufficiently suppressed.

[0068] Furthermore, it was found that when visually recognizing an image closer to the periphery of the image display element 35 from the observer's viewpoint O, that is, when the angle between the line of sight (= ray S) when visually recognizing the image from viewpoint O and the normal to the display surface of the image display element 35 is larger, the ghosting caused by ray S is more obvious.

[0069] In contrast, in the optical element 10 of this invention, such as Figure 1 As shown, polarizers A100 and B400 are configured such that, at their respective intersection points on the polarizer A100 side, a straight line L forming a 90° angle with the absorption axis of polarizer B400 and virtual lines L1 to L4 intersect at position Z. Therefore, when optical element 10 is used in an image display device, by observing from position Z, non-reciprocating light rays S emitted within the optical system can be suppressed in the absorption polarizer A100, which has a curved surface portion, thereby suppressing ghosting in the observed displayed image.

[0070] In particular, the aforementioned superior effect is even more pronounced in suppressing ghosting in the image display area closer to the periphery of the image display element.

[0071] [Specific method for position Z]

[0072] For example, the position Z in an optical element can be determined by the following method.

[0073] First, in the optical element, locate the position X closest to polarizer B on the surface of polarizer A on the polarizer B side. Next, locate the position Y on the surface of polarizer B on the polarizer A side that is closest to position X. Based on the identified positions X and Y, determine the straight line L passing through positions X and Y. In other words, the perpendicular line from position X to polarizer B is the straight line L, and the intersection of this perpendicular line and the surface of polarizer B on the polarizer A side is position Y. Furthermore, in Figure 1 In the diagram, position Y is located at the center of polarizer B.

[0074] Next, assume that point W exists on line L and is located on the opposite side of position X when viewed from position Y. Then, find the virtual lines Lw1, Lw2, Lw3 and Lw4 that pass through point W, form an angle of 30° with line L and satisfy the following conditions.

[0075] Requirements: The angle between line Lp1, which is projected orthogonally from virtual line Lw1 to polarizer B, and line Lp2, which is projected orthogonally from virtual line Lw2 to polarizer B, is 90°; the angle between line Lp2 and line Lp3, which is projected orthogonally from virtual line Lw3 to polarizer B, is 90°; the angle between line Lp3 and line Lp4, which is projected orthogonally from virtual line Lw4 to polarizer B, is 90°; the angle between line Lp4 and line Lp1 is 90°; and the angle between line Lp1 and the absorption axis of polarizer B is 45°.

[0076] Next, using an AxoScan OPMF-1 (manufactured by Opto Science, Inc.), the absorption axis of polarizer A at the intersection of virtual line Lw1 and polarizer A, and the absorption axis of polarizer B at the intersection of virtual line Lw1 and polarizer B, were measured. When measuring the absorption axis of polarizer A, polarizer B was removed from the optical element, and polarizer A was fixed in a manner where the direction of the AxoScan measurement beam was aligned with virtual line Lw1 without changing the positional relationship between virtual line Lw1 and polarizer A, while the absorption axis was measured. Similarly, when measuring the absorption axis of polarizer B, polarizer A was removed from the optical element, and polarizer B was fixed in a manner where the direction of the AxoScan measurement beam was aligned with virtual line Lw1 without changing the positional relationship between virtual line Lw1 and polarizer B, while the absorption axis was measured.

[0077] By comparing the measured values ​​of the two, it is determined whether the angle between the absorption axis of polarizer A at the intersection of virtual line Lw1 and polarizer A, and the absorption axis of polarizer B at the intersection of virtual line Lw1 and polarizer B, is 90° when viewed from the direction extending from virtual line Lw1.

[0078] The same measurement and judgment were also performed on the straight line L and the virtual lines Lw2 to Lw4.

[0079] While moving the position of point W on line L, the virtual lines Lw1 to Lw4 are repeatedly set and the absorption axes of polarizers A and B at their intersections with each virtual line are measured, following the method described above. As a result, for all lines L and virtual lines Lw1 to Lw4, when the angle between the absorption axis of polarizer A and the absorption axis of polarizer B is 90° when viewed from the aforementioned direction, point W is determined as position Z. Furthermore, the virtual lines Lw1 to Lw4 passing through point W (position Z) at this time correspond to the virtual lines L1 to L4 as specified in the aforementioned specific requirements.

[0080] In addition, regarding this optical element, the virtual lines L1, L2, L3 and L4 are all different, as are the straight lines Lp1, Lp2, Lp3 and Lp4.

[0081] The optical element will now be described in detail.

[0082] The absorption polarizer A and absorption polarizer B with curved surfaces in this optical element are not particularly restricted as long as they are configured such that polarizers A and B have a position Z that satisfies a specific requirement.

[0083] Additionally, in this specification, "having a curved portion" means that at least a portion of the polarizer is formed as a curved surface.

[0084] Polarizer A is preferably formed as a curved surface. Furthermore, polarizer A preferably has a three-dimensional curved surface, and is preferably formed as a three-dimensional curved surface. Additionally, a three-dimensional curved surface refers to a non-developable surface. A developable surface refers to a curved surface that can be unfolded into a plane without stretching, that is, a curved surface that can be produced by bending or cutting a plane.

[0085] Furthermore, polarizer A preferably has a convex surface on the side with polarizer B and a concave surface on the side opposite to polarizer B, and more preferably has a curved surface with a constant radius of curvature. Here, a constant radius of curvature means that the difference between the maximum and minimum values ​​of the radius of curvature on the surface of optical components such as polarizer A is within 5% of the minimum value of the radius of curvature.

[0086] In addition, when polarizer A has a curved surface with a constant radius of curvature, the radius of curvature can be appropriately selected according to the size and application of the optical element and the image display device, preferably 20 to 1000 mm, more preferably 30 to 200 mm.

[0087] Polarizer B can be planar or have a curved portion. In the case where polarizer B has a curved portion, including preferred embodiments, it can be the same as polarizer A described above.

[0088] Regarding this optical element, it is preferable that the relationship between position Z, polarizer A, and polarizer B is satisfied throughout the entire region of polarizer B, namely, assuming a straight line Lz connecting position Z and polarizer B, when viewed from the direction extending from line Lz, the angle between the local absorption axis of polarizer A at the intersection with line Lz and the local absorption axis of polarizer B at the intersection with line Lz is 90°. By satisfying the above relationship throughout the entire region of polarizer B, ghosting occurring in the displayed image can be suppressed more effectively in an image display device manufactured using this optical element.

[0089] Furthermore, the determination of whether the optical element satisfies the above relationship can be carried out according to the specific method of position Z described above.

[0090] The following sections will provide detailed descriptions of polarizer A and polarizer B.

[0091] [Polarizer A]

[0092] Polarizer A is an absorption polarizer. As polarizer A, a known absorption polarizer having at least a light-absorbing anisotropic layer containing a dichroic material can be used.

[0093] As an anisotropic light-absorbing layer, examples include layers comprising a matrix compound and a dichroic material, and preferably layers comprising a liquid crystal compound and a dichroic material.

[0094] The orientation degree of the dichroic material in the light-absorbing anisotropic layer is preferably 0.95 or higher, more preferably 0.97 or higher. The higher the orientation degree, the more effectively ghosting can be suppressed. There is no particular limit to the upper limit of the above orientation degree, which can be 0.99 or lower, preferably 0.98 or lower.

[0095] As polarizer A, it is preferable to have multiple regions with absorption axes that have different directions. That is, it is preferable that within the plane of polarizer A, there are two or more regions where the directions of local absorption axes are not parallel to each other.

[0096] Figure 3 The image shows an example of the orientation distribution of the absorption axes when polarizer A has multiple regions with different directions of absorption axes. Figure 3 This is a schematic diagram showing the distribution of the orthographic projection of the local absorption axial plane (polarizer B) of polarizer A. Figure 3 In the diagram, each "AA" indicates the direction of the orthographic projection of the absorption axis. For example... Figure 3 As shown, it is clear that in the case of multiple regions with different directions of absorption axis orthogonal projection AA, there are also multiple regions with different directions of absorption axis within polarizer A.

[0097] As described above (specific method for position Z), the absorption axis in polarizer A can be determined using the AxoScan OPMF-1.

[0098] A polarizer A having an absorption axis oriented as described above can, for example, be formed by the method described in the "Method for Forming an Anisotropic Light Absorption Layer" (described later).

[0099] Furthermore, regarding the absorption axis in polarizer A, the method is not limited to the above as long as a position Z satisfying the specific requirement exists. For example, a position Z satisfying the specific requirement can exist by combining polarizer A, whose absorption axes are parallel throughout, and polarizer B, which has multiple regions with mutually different absorption axes.

[0100] <<Resin Substrate>>

[0101] Polarizer A may include a resin substrate. When polarizer A is formed into a curved shape, the peak temperature of tanδ of the resin substrate is preferably 170°C or lower. Moreover, from the viewpoint that it can be formed at a lower temperature, the peak temperature of tanδ is preferably 150°C or lower, and more preferably 130°C or lower.

[0102] Here, the method for determining tanδ is described. Using a dynamic viscoelasticity measuring apparatus (IT Keisoku Seigyo Co., Ltd. DVA-200), film samples that had been conditioned for more than 2 hours at a temperature of 25°C and a humidity of 60% RH were measured under the following conditions, and the values ​​were used to determine the value of tanδ (=E” / E’).

[0103] Device: DVA-200 manufactured by IT Keisoku Seigyo Co., Ltd.

[0104] Sample size: 5mm, length 50mm (gap 20mm)

[0105] Measurement conditions: Tensile mode

[0106] Measurement temperature: -150℃~220℃

[0107] Heating rate: 5℃ / min

[0108] Frequency: 1Hz

[0109] Furthermore, in optical applications, stretched resin substrates are often used, as the peak temperature of tanδ is frequently increased through stretching. For example, in TAC (triacetyl cellulose) substrates (TG40, manufactured by FUJIFILM Corporation), the peak temperature of tanδ is above 180°C.

[0110] There are no particular limitations on the resin substrate, and substrates made of various optical resins can be used, but resin substrates with a tanδ peak temperature of 170°C or lower are preferred. Examples of resins constituting such a resin substrate include, for example, polyolefins such as polyethylene, polypropylene, and norbornene polymers; cyclic olefin resins; polyvinyl alcohol; polyethylene terephthalate; acrylic resins such as polymethacrylate and polyacrylate; polyethylene naphthalate; polycarbonate; polysulfone; polyethersulfone; polyetherketone; and polyphenylene sulfide and polyphenylene oxide. Among these, cyclic olefin resins, polyethylene terephthalate, or acrylic resins are preferred from the viewpoint of being readily available on the market or having excellent transparency; cyclic olefin resins or polymethacrylate are more preferred.

[0111] Commercially available resin substrates include TECHNOLLOY S001G, TECHNOLLOY S014G, TECHNOLLOY S000, TECHNOLLOY C001 and TECHNOLLOY C000 (Sumika Acryl Co., Ltd.), LUMIRROR U type, LUMIRROR FX10 and LUMIRROR SF20 (TORAY INDUSTRIES, INC.), HK-53A (Higashiyama Film Co., Ltd.), TEFLEX FT3 (Teijin DuPont Films Japan Ltd.), ESSINA and SCA40 (SEKISUI CHEMICAL CO.,LTD.), ZEONOR film (ZEON CORPORATION.), and ARTON film (JSR Corporation).

[0112] There are no particular limitations on the thickness of the substrate, but it is preferably 5 to 300 μm, more preferably 5 to 100 μm, and even more preferably 5 to 30 μm.

[0113] <<Light Absorption Anisotropic Layer>>

[0114] As described above, the light-absorbing anisotropic layer preferably comprises a liquid crystal compound and a dichroic material.

[0115] This light-absorbing anisotropic layer can be formed using a composition comprising a liquid crystal compound and a dichroic substance (hereinafter also referred to as a "composition for forming a light-absorbing anisotropic layer").

[0116] At the point where the decrease in polarization during heating is suppressed, it is preferable that the liquid crystal compound and / or dichroic substance included in the composition for forming anisotropic light-absorbing layers has free radical polymerizable groups. The molar content of free radical polymerizable groups relative to the weight of the solid components of the composition for forming anisotropic light-absorbing layers is preferably 0.6 mmol / g or more, more preferably 1.0 mmol / g or more, and even more preferably 1.5 mmol / g or more. There is no particular limitation on the upper limit, but it is preferably 5 mmol / g or less.

[0117] <Liquid Crystal Compounds>

[0118] The composition for forming anisotropic light-absorbing layers contains a liquid crystal compound.

[0119] The liquid crystal compound is preferably a liquid crystal compound that does not exhibit dichroism in the visible region.

[0120] As a liquid crystal compound, either a low-molecular-weight liquid crystal compound or a high-molecular-weight liquid crystal compound can be used. Here, "low-molecular-weight liquid crystal compound" refers to a liquid crystal compound that does not have repeating units in its chemical structure. Here, "high-molecular-weight liquid crystal compound" refers to a liquid crystal compound that has repeating units in its chemical structure.

[0121] As a low-molecular-weight liquid crystal compound, examples include the liquid crystal compounds described in paragraphs

[0027] to

[0034] of Japanese Patent Application Publication No. 2013-228706. Among these, a low-molecular-weight liquid crystal compound exhibiting smectic properties is preferred.

[0122] Examples of polymeric liquid crystal compounds include, for instance, the thermotropic liquid crystal polymer described in Japanese Patent Application Publication No. 2011-237513. Furthermore, the polymeric liquid crystal compound preferably has crosslinking groups (e.g., acryloyl and methacryloyl groups) at its ends.

[0123] A single liquid crystal compound can be used alone, or two or more can be used in combination. It is preferred to use a combination of high molecular weight liquid crystal compounds and low molecular weight liquid crystal compounds.

[0124] The content of the dichroic substance in the composition for forming the anisotropic light-absorbing layer is preferably 25 to 2000 parts by mass, more preferably 33 to 1000 parts by mass, and even more preferably 50 to 500 parts by mass, relative to 100 parts by mass of the dichroic substance. With the content of the dichroic compound within the above range, the orientation degree of the polarizer is further improved.

[0125] Considering that the orientation degree of the resulting light absorption anisotropy layer is higher, the liquid crystal compound is preferably a polymeric liquid crystal compound, and more preferably a polymeric liquid crystal compound containing the repeating unit (hereinafter also simply referred to as "repeating unit (1)") represented by the following formula (1).

[0126] [Chemical Formula 1]

[0127]

[0128] In the above formula (1), P1 represents the main chain of the repeating unit, L1 represents the single bond or divalent linking group, SP1 represents the spacer group, M1 represents the mesocrystalline group, and T1 represents the terminal group.

[0129] As the main chain of the repeating unit represented by P1, for example, the groups represented by the following formulas (P1-A) to (P1-D) can be cited. Among them, from the viewpoint of the diversity of monomers that can be used as raw materials and ease of processing, the group represented by the following formula (P1-A) is preferred.

[0130] [Chemical Formula 2]

[0131]

[0132] In equations (P1-A) to (P1-D), "*" indicates the bonding position with L1 in equation (1). In equation (P1-A), R 1 Represents a hydrogen atom or a methyl group. In formula (P1-D), R 2 Indicates alkyl group.

[0133] Considering the reason that the orientation degree of the resulting light-absorbing anisotropic layer becomes higher, the group represented by formula (P1-A) is preferably a unit of a partial structure of poly(meth)acrylate obtained by polymerization of (meth)acrylate.

[0134] Considering the reason that the orientation degree of the obtained light-absorbing anisotropic layer is higher, the group represented by formula (P1-B) is preferably an ethylene glycol unit in polyethylene glycol obtained by polymerizing ethylene glycol.

[0135] Considering the reason that the orientation degree of the obtained light-absorbing anisotropic layer is higher, the group represented by formula (P1-C) is preferably a propylene glycol unit obtained by polymerizing propylene glycol.

[0136] Considering the reason that the orientation degree of the obtained light-absorbing anisotropic layer becomes higher, the group represented by formula (P1-D) is preferably a siloxane unit of polysiloxane obtained by polycondensation of silanol.

[0137] L1 is a single bond or a divalent linker group.

[0138] Examples of divalent linking groups represented by L1 include -C(O)O-, -OC(O)-, -O-, -S-, and -C(O)NR. 3 -、-NR 3 C(O)-, -SO2- and -NR 3 R 4 - etc. In the formula, R 3 and R 4 Each of the following can be independently represented: a hydrogen atom and an alkyl group having 1 to 6 carbon atoms that may have substituents.

[0139] When P1 is a group represented by formula (P1-A), considering that the orientation degree of the resulting light absorption anisotropy layer becomes higher, L1 is preferably a group represented by -C(O)O-.

[0140] When P1 is a group represented by formulas (P1-B) to (P1-D), L1 is preferably a single bond, considering that the orientation degree of the resulting light absorption anisotropy layer becomes higher.

[0141] Considering factors such as ease of liquid crystal properties and availability of raw materials, the spacer group represented by SP1 preferably includes at least one structure selected from the group consisting of ethylene oxide structure, propylene oxide structure, polysiloxane structure and fluorinated alkylene structure.

[0142] Here, the ethylene oxide structure represented by SP1 is preferably *-(CH2-CH2O). n1 -* represents the group. In the formula, n1 represents an integer from 1 to 20, and * represents the bonding position with L1 or M1 in the above formula (1). Considering that the orientation degree of the obtained light absorption anisotropic layer is higher, n1 is preferably an integer from 2 to 10, more preferably an integer from 2 to 4, and most preferably 3.

[0143] Furthermore, considering that the orientation degree of the resulting light absorption anisotropy layer is higher, the propylene oxide structure represented by SP1 is preferably *-(CH(CH3)-CH2O). n2 -* represents the group. In the formula, n2 represents an integer from 1 to 3, and * represents the bonding position with L1 or M1.

[0144] Furthermore, considering that the orientation degree of the resulting light absorption anisotropy layer is higher, the polysiloxane structure represented by SP1 is preferably *-(Si(CH3)2-O). n3 -* represents the group. In the formula, n3 represents an integer from 6 to 10, and * represents the bonding position with L1 or M1.

[0145] Furthermore, considering the higher orientation degree of the resulting anisotropic light absorption layer, the fluorinated alkylene structure represented by SP1 is preferably *-(CF2-CF2). n4 -* represents the group. In the formula, n4 represents an integer from 6 to 10, and * represents the bonding position with L1 or M1.

[0146] The mesocrystalline group represented by M1 is a group that represents the main framework of liquid crystal molecules that contribute to the formation of liquid crystals. Liquid crystal molecules exhibit liquid crystal properties in an intermediate state (intermediate phase) between the crystalline state and the isotropic liquid state. There are no particular limitations regarding the mesocrystalline group; for example, one can refer to "Flussige Kristalle in Tabellen II" (VEB Deutsche Verlag fur Grundstoff Industrie, Leipzig, 1984), especially pages 7-16, and the records in the Liquid Crystal Handbook Editorial Committee, Liquid Crystal Handbook (Maruzen, 2000) (especially Chapter 3).

[0147] As a mesocrystalline group, it is preferably a group having at least one cyclic structure selected from the group consisting of aromatic hydrocarbon groups, heterocyclic groups and alicyclic groups.

[0148] Considering that the orientation degree of the resulting light absorption anisotropy layer becomes higher, the mesocrystalline group preferably has an aromatic hydrocarbon group, more preferably has 2 to 4 aromatic hydrocarbon groups, and even more preferably has 3 aromatic hydrocarbon groups.

[0149] As a mesocrystalline group, from the viewpoints of liquid crystal properties, liquid crystal phase transition temperature adjustment, raw material availability and synthetic applicability, and from the viewpoint of better effects of the present invention, it is preferred to be a group represented by the following formula (M1-A) or the following formula (M1-B), and more preferably a group represented by formula (M1-B).

[0150] [Chemical Formula 3]

[0151]

[0152] In formula (M1-A), A1 is a divalent group selected from the group consisting of aromatic hydrocarbon groups, heterocyclic groups, and alicyclic groups. These groups may be substituted with alkyl, fluorinated alkyl, alkoxy, or substituents.

[0153] The divalent group represented by A1 is preferably a 4- to 6-membered ring. Furthermore, the divalent group represented by A1 can be a monocyclic ring or a fused ring.

[0154] * indicates the bonding position with SP1 or T1.

[0155] Examples of divalent aromatic hydrocarbon groups represented by A1 include phenylene, naphthylene, fluorene-diyl, anthracene-diyl, and tetraphenyl-diyl. From the perspective of the diversity of mesocrystalline framework design and the availability of raw materials, phenylene or naphthylene is preferred, and phenylene is more preferred.

[0156] The divalent heterocyclic group represented by A1 can be either aromatic or non-aromatic, but from the viewpoint of further improving the degree of orientation, a divalent aromatic heterocyclic group is preferred.

[0157] Examples of atoms other than carbon that constitute a divalent aromatic heterocyclic group include nitrogen, sulfur, and oxygen atoms. When an aromatic heterocyclic group has multiple atoms that form the ring besides carbon, these atoms may be the same or different.

[0158] Specific examples of divalent aromatic heterocyclic groups include, for example, pyridinyl (pyridin-diyl), pyridazin-diyl, imidazole-diyl, thiophenyl (thiophen-diyl), quinolineyl (quinoline-diyl), isoquinolineyl (isoquinoline-diyl), oxazole-diyl, thiazole-diyl, oxadiazole-diyl, benzothiazole-diyl, benzothiadiazole-diyl, phthalimide-diyl, thienothiazole-diyl, thiazonothiazole-diyl, thienothiphene-diyl, and thienooxazole-diyl.

[0159] Specific examples of the divalent alicyclic group represented by A1 include cyclopentylene and cyclohexylene.

[0160] In the above formula (M1-A), a1 represents an integer from 1 to 10. When a1 is 2 or higher, multiple A1s can be the same or different.

[0161] In formula (M1-B), A2 and A3 are each independently a divalent group selected from the group consisting of aromatic hydrocarbon groups, heterocyclic groups, and alicyclic groups. Specific examples and preferred embodiments of A2 and A3 are the same as A1 in formula (M1-A), therefore their description is omitted.

[0162] In formula (M1-B), a2 represents an integer from 1 to 10. When a2 is 2 or more, multiple A2s can be the same or different, multiple A3s can be the same or different, and multiple LA1s can be the same or different. Considering that the orientation degree of the obtained light absorption anisotropy layer becomes higher, a2 is preferably an integer of 2 or more, and more preferably 2.

[0163] In formula (M1-B), when a2 is 1, LA1 is a divalent linking group. When a2 is 2 or more, each of the multiple LA1s is independently a single bond or a divalent linking group, and at least one of the multiple LA1s is a divalent linking group. When a2 is 2, considering that the orientation degree of the resulting anisotropic light absorption layer becomes higher, it is preferable that one of the two LA1s is a divalent linking group and the other is a single bond.

[0164] In formula (M1-B), examples of divalent linking groups represented by LA1 include -O- and -(CH2). g -、-(CF2) g -、-Si(CH3)2-、-(Si(CH3)2O) g -、-(OSi(CH3)2) g-(g represents an integer from 1 to 10.), -N(Z)-, -C(Z)=C(Z')-, -C(Z)=N-, -N=C(Z)-, -C(Z)2-C(Z')2-, -C(O)-, -OC(O)-, -C(O)O-, -OC(O)O-, -N(Z)C(O)-, -C( O)N(Z)-, -C(Z)=C(Z')-C(O)O-, -OC(O)-C(Z)=C(Z')-, -C(Z)=N-, -N=C(Z)-, -C(Z)=C(Z')-C(O)N(Z”)-, -N(Z”)-C(O)-C(Z)=C(Z’)-, -C( Z)=C(Z')-C(O)-S-, -SC(O)-C(Z)=C(Z')-, -C(Z)=NN=C(Z')- (Z, Z', Z” independently represent a hydrogen atom, C1-C4 alkyl, cycloalkyl, aryl, cyano, or halogen atom.), -C≡C-, -N=N-, -S-, -S(O)-, -S(O)(O)-, -(O)S(O)O-, -O(O)S(O)O-, -SC(O)-, and -C(O)S-, etc. Among these, -C(O)O- is preferred because it results in a higher degree of orientation of the light absorption anisotropy layer. LA1 can also be a group composed of two or more of these groups.

[0165] Specific examples of M1 include the following structures. Additionally, in the following examples, "Ac" represents an acetyl group.

[0166] [Chemical Formula 4]

[0167]

[0168] [Chemical Formula 5]

[0169]

[0170] Examples of terminal groups represented by T1 include hydrogen atoms, halogen atoms, cyano groups, nitro groups, hydroxyl groups, alkyl groups with 1 to 10 carbon atoms, alkoxy groups with 1 to 10 carbon atoms, alkylthio groups with 1 to 10 carbon atoms, alkoxycarbonyloxy groups with 1 to 10 carbon atoms, alkoxycarbonyl groups with 1 to 10 carbon atoms (ROC(O)-: R is alkyl), acyloxy groups with 1 to 10 carbon atoms, acylamino groups with 1 to 10 carbon atoms, alkoxycarbonylamino groups with 1 to 10 carbon atoms, sulfonylamino groups with 1 to 10 carbon atoms, aminosulfonyl groups with 1 to 10 carbon atoms, carbamoyl groups with 1 to 10 carbon atoms, sulfinyl groups with 1 to 10 carbon atoms, urea groups with 1 to 10 carbon atoms, and groups containing (meth)acryloyloxy groups. As an example of the group containing (meth)acryloyloxy, one can cite the group represented by -LA (L represents a single bond or a linking group. Specific examples of linking groups are the same as L1 and SP1 above. A represents (meth)acryloyloxy).

[0171] Considering the reason that the orientation degree of the resulting anisotropic light-absorbing layer is higher, T1 is preferably an alkoxy group with 1 to 10 carbon atoms, more preferably an alkoxy group with 1 to 5 carbon atoms, and even more preferably a methoxy group. These terminal groups can be further replaced by these groups or polymerizable groups described in Japanese Patent Application Publication No. 2010-244038.

[0172] Considering the need for a higher degree of orientation in the resulting anisotropic light-absorbing layer, the number of atoms in the main chain of T1 is preferably 1 to 20, more preferably 1 to 15, even more preferably 1 to 10, and particularly preferably 1 to 7. By having the number of atoms in the main chain of T1 be 20 or less, the orientation of the polarizer is further improved. Here, "main chain" in T1 refers to the longest molecular chain bonded to M1, and hydrogen atoms are not included in the number of atoms in the main chain of T1. For example, when T1 is n-butyl, the number of atoms in the main chain is 4; when T1 is sec-butyl, the number of atoms in the main chain is 3.

[0173] Considering that the orientation degree of the obtained light absorption anisotropic layer is higher, the content of repeating unit (1) is preferably 20 to 100% by mass relative to the total repeating units of the polymer liquid crystal compound.

[0174] In this specification, the content of each repeating unit contained in the polymeric liquid crystal compound is calculated based on the amount (mass) of each monomer used to obtain each repeating unit.

[0175] The polymeric liquid crystal compound may contain only one repeating unit (1) or two or more. Considering that the orientation degree of the resulting light absorption anisotropy layer is higher, it is preferable to include two repeating units (1) in the polymeric liquid crystal compound.

[0176] In the case where the polymeric liquid crystal compound contains two repeating units (1), considering that the orientation degree of the resulting light absorption anisotropy layer is higher, in one of them (repeating unit A), the terminal group represented by T1 is an alkoxy group, and in the other (repeating unit B), the terminal group represented by T1 is a group other than an alkoxy group.

[0177] Considering the reason that the orientation degree of the obtained light absorption anisotropy layer becomes higher, in the above repeating unit B, the terminal group represented by T1 is preferably alkoxycarbonyl, cyano or a group containing (meth)acryloyloxy, more preferably alkoxycarbonyl or cyano.

[0178] Considering the reason that the orientation degree of the obtained light absorption anisotropic layer is higher, the ratio (A / B) of the content of the above-mentioned repeating unit A in the polymeric liquid crystal compound to the content of the above-mentioned repeating unit B in the polymeric liquid crystal compound is preferably 50 / 50 to 95 / 5, more preferably 60 / 40 to 93 / 7, and even more preferably 70 / 30 to 90 / 10.

[0179] (Repeated unit (3-2))

[0180] The polymeric liquid crystal compound may also contain repeating units represented by the following formula (3-2) (also referred to as "repeating unit (3-2)" in this specification). This provides the following advantages: the solubility of the polymeric liquid crystal compound in solvents is improved, and the adjustment of the liquid crystal phase transition temperature becomes easier.

[0181] The repeating unit (3-2) differs from the repeating unit (1) mentioned above in that it does not have at least a mesocrystalline group.

[0182] When the polymeric liquid crystal compound contains repeating units (3-2), the polymeric liquid crystal compound can be a copolymer of repeating units (1) and (3-2), and further can be a copolymer containing repeating units A and B. The aforementioned copolymer can be any polymer such as end-capped polymers, alternating polymers, random polymers, and graft polymers.

[0183] [Chemical Formula 6]

[0184]

[0185] In equation (3-2), P3 represents the main chain of the repeating unit, L3 represents a single bond or a divalent linking group, SP3 represents a spacer group, and T3 represents a terminal group.

[0186] The specific examples of P3, L3, SP3 and T3 in equation (3-2) are the same as P1, L1, SP1 and T1 in equation (1) above.

[0187] From the viewpoint of improving the intensity of the light-absorbing anisotropic layer, T3 in formula (3-2) preferably has polymerizable groups.

[0188] The content of repeating units (3-2) is preferably 0.5 to 40% by mass relative to 100% by mass of the total repeating units in the polymeric liquid crystal compound, and more preferably 1 to 30% by mass.

[0189] In a polymeric liquid crystal compound, there may be only one repeating unit (3-2) or there may be two or more repeating units. When there are two or more repeating units (3-2), the total amount is preferably within the range described above.

[0190] (weight-average molecular weight)

[0191] Considering the need for a higher degree of orientation in the resulting anisotropic light-absorbing layer, the weight-average molecular weight (Mw) of the polymeric liquid crystal compound is preferably 1,000 to 500,000, more preferably 2,000 to 300,000. If the Mw of the polymeric liquid crystal compound is within the above range, the processing of the polymeric liquid crystal compound becomes easier.

[0192] In particular, from the viewpoint of suppressing cracks during coating, the weight-average molecular weight (Mw) of the polymeric liquid crystal compound is preferably 10,000 or more, and more preferably 10,000 to 300,000.

[0193] Furthermore, from the viewpoint of temperature tolerance of orientation, the weight-average molecular weight (Mw) of the polymeric liquid crystal compound is preferably less than 10,000, and more preferably 2,000 or more but less than 10,000.

[0194] The weight-average molecular weight and number-average molecular weight described in this specification are values ​​determined by gel permeation chromatography (GPC).

[0195] • Solvent (eluent): N-methylpyrrolidone

[0196] • Device Name: TOSOH HLC-8220GPC

[0197] • String: Connect 3 TOSOH TSKgelSuperAWM-H (6mm×15cm) tubes for use.

[0198] • Column temperature: 25℃

[0199] • Sample concentration: 0.1% by mass

[0200] • Flow rate: 0.35 mL / min

[0201] • Calibration curve: The calibration curve was obtained using seven samples of TSK standard polystyrene prepared by TOSOH CORPORATION with Mw = 2,800,000 to 1,050 (Mw / Mn = 1.03 to 1.06).

[0202] (content)

[0203] The liquid crystal compound is preferably present in an amount of 50 to 99% by mass of the solid components in the composition for forming anisotropic light-absorbing layers, and more preferably in an amount of 70 to 96% by mass.

[0204] Here, "solid components in the composition for forming anisotropic light-absorbing layers" refers to components other than solvents. Specific examples of solid components include the aforementioned liquid crystal compounds and the dichroic substances, polymerization initiators, and surfactants described later.

[0205] <Dichromatic substances>

[0206] The composition for forming anisotropic light-absorbing layers contains a dichroic substance.

[0207] There are no particular restrictions on dichroic substances; known dichroic substances (dichroic pigments) can be used, such as visible light absorbing substances (dichroic pigments), luminescent substances (fluorescent substances, phosphorescent substances), ultraviolet light absorbing substances, infrared light absorbing substances, nonlinear optical substances, carbon nanotubes, and inorganic substances (such as quantum rods).

[0208] Examples of dichroic substances include, for example, paragraphs

[0067] to

[0071] of Japanese Patent Application Publication No. 2013-228706, paragraphs

[0008] to

[0026] of Japanese Patent Application Publication No. 2013-227532, paragraphs

[0008] to

[0015] of Japanese Patent Application Publication No. 2013-209367, paragraphs

[0045] to

[0058] of Japanese Patent Application Publication No. 2013-14883, paragraphs

[0012] to

[0029] of Japanese Patent Application Publication No. 2013-101328. Paragraphs

[0009] to

[0017] of the Japanese JP 2013-37353, paragraphs

[0051] to

[0065] of the Japanese JP 2012-063387, paragraphs

[0049] to

[0073] of the Japanese JP 2012-063387, paragraphs

[0016] to

[0018] of the Japanese JP 2001-133630, paragraphs

[0030] to

[0169] of the Japanese JP 2011-215337, and Japanese JP 2010-1062 Paragraphs

[0021] to

[0075] of Japanese Publication No. 42, paragraphs

[0011] to

[0025] of Japanese Publication No. 2010-215846, paragraphs

[0017] to

[0069] of Japanese Publication No. 2011-048311, paragraphs

[0013] to

[0133] of Japanese Publication No. 2011-213610, paragraphs

[0074] to

[0246] of Japanese Publication No. 2011-237513, paragraphs

[0005] to

[0051] of Japanese Publication No. 2016-006502, and International Publication No. 201 The dichroic substances described in paragraphs

[0005] to

[0041] of Publication No. 6 / 060173, paragraphs

[0008] to

[0062] of Publication No. 2016 / 136561, paragraphs

[0014] to

[0033] of Publication No. 2017 / 154835, paragraphs

[0014] to

[0033] of Publication No. 2017 / 154695, paragraphs

[0013] to

[0037] of Publication No. 2017 / 195833, and paragraphs

[0014] to

[0034] of Publication No. 2018 / 164252.

[0209] The light-absorbing anisotropic layer may contain two or more dichroic materials. For example, from the viewpoint of making the obtained liquid crystal layer close to black, it is preferable to use at least one dichroic material with a maximum absorption wavelength in the wavelength range of 370 to 550 nm and at least one dichroic material with a maximum absorption wavelength in the wavelength range of 500 to 700 nm.

[0210] The dichroic material included in the composition for forming anisotropic light-absorbing layers may have cross-linking groups. In particular, from the viewpoint of suppressing changes in polarization degree during heating, the dichroic material preferably has cross-linking groups.

[0211] Examples of crosslinking groups include (meth)acryloyl, epoxy, oxetyl, and styryl, with (meth)acryloyl being preferred.

[0212] (content)

[0213] Considering the reason that the orientation degree of the dichroic material becomes higher, the content of the dichroic material in the composition for forming the light absorption anisotropic layer is preferably 1 to 400 parts by mass relative to 100 parts by mass of the above-mentioned liquid crystal compound, more preferably 2 to 100 parts by mass, and even more preferably 5 to 30 parts by mass.

[0214] <surfactants>

[0215] The composition for forming anisotropic light-absorbing layers may contain a surfactant.

[0216] As the surfactant included in the composition for forming anisotropic light-absorbing layers, known surfactants can be used, but copolymers having repeating units containing fluorinated alkyl groups (hereinafter also simply referred to as "repeating unit F") and repeating units containing ring structures (hereinafter also simply referred to as "repeating unit M") are preferred.

[0217] (Repeating unit F)

[0218] The repeating unit F of the copolymer described above is preferably the repeating unit represented by the following formula (a).

[0219] [Chemical Formula 7]

[0220]

[0221] In equation (a) above, R a1 R represents an alkyl group having 1 to 20 hydrogen atoms or carbon atoms. a2 It refers to an alkyl group with 1 to 20 carbon atoms or an alkenyl group with 2 to 20 carbon atoms, wherein at least one carbon atom has a fluorine atom as a substituent.

[0222] In equation (a) above, considering the reason that the orientation defects of the obtained anisotropic light absorption layer are further suppressed, R a2 Preferably, it is an alkyl group with 1 to 10 carbon atoms or an alkenyl group with 2 to 10 carbon atoms, having at least one carbon atom as a fluorine atom as a substituent; more preferably, it is an alkyl group with 1 to 10 carbon atoms; and especially preferably, R. a2 More than half of the carbon atoms contained in it have fluorine atoms as substituents.

[0223] The repeating unit F of the copolymer described above is more preferably the repeating unit represented by the following formula (b).

[0224] [Chemical Formula 8]

[0225]

[0226] In equation (b) above, R a1 The alkyl group represents 1 to 20 hydrogen atoms or carbon atoms, ma and na represent integers above 0 independently, and X represents a hydrogen atom or a fluorine atom.

[0227] Here, ma is preferably an integer greater than or equal to 1 and less than or equal to 10, and na is preferably greater than or equal to 4 and less than or equal to 12.

[0228] As monomers (hereinafter also simply referred to as "monomers containing fluoroalkyl groups") that form the repeating unit F of the copolymer described above, examples include 2,2,2-(meth)acrylate trifluoroethyl ester, 2,2,3,3,3-pentafluoro(meth)acrylate propyl ester, 2-(perfluorobutyl)(meth)acrylate ethyl ester, 2-(perfluorohexyl)(meth)acrylate ethyl ester, 2-(perfluorooctyl)(meth)acrylate ethyl ester, 2-(perfluorodecyl)(meth)acrylate ethyl ester, 2-(perfluoro-3-methylbutyl)(meth)acrylate ethyl ester, 2-(perfluoro-5-methylhexyl)(meth)acrylate ethyl ester, 2-(perfluoro-7-methyloctyl)(meth)acrylate ethyl ester, 1H,1H,3H-tetrafluoropropyl(meth)acrylate, 1H, 1H,5H-pentafluoro(meth)acrylate, 1H,1H,7H-dodecylfluoroheptyl(meth)acrylate, 1H,1H,9H-hexadecylfluorononyl(meth)acrylate, 1H-1-(trifluoromethyl)(meth)acrylate trifluoroethyl ester, 1H,1H,3H-hexafluoro(meth)acrylate butyl ester, 3-perfluorobutyl-(meth)acrylate 2-hydroxypropyl ester, 3-perfluorohexyl-(meth)acrylate 2-hydroxypropyl ester, 3-perfluorooctyl-(meth)acrylate 2-hydroxypropyl ester, 3-(perfluoro-3-methylbutyl)-(meth)acrylate 2-hydroxypropyl ester, 3-(perfluoro-5-methylhexyl)-(meth)acrylate 2-hydroxypropyl ester, and 3-(perfluoro-7-methyloctyl)-(meth)acrylate 2-hydroxypropyl ester.

[0229] Regarding the proportion of monomers containing fluoroalkyl groups copolymerized, from the viewpoint of reactivity and surface modification effect, it is preferably 0.01 to 100 moles, more preferably 0.1 to 50 moles, and even more preferably 1 to 30 moles, relative to 1 mole of monomers having mesocrystalline groups described later.

[0230] (Repeating unit M)

[0231] The repeating unit M of the above copolymer only needs to be a unit containing a ring structure.

[0232] As a ring structure, for example, at least one ring structure selected from the group consisting of aromatic hydrocarbon groups, heterocyclic groups, and alicyclic groups can be cited. From the viewpoint of suppressing orientation defects, the repeating unit M preferably has two or more ring structures.

[0233] The repeating unit M of the copolymer described above is more preferably the repeating unit represented by the following formula (b).

[0234] [Chemical Formula 9]

[0235]

[0236] In equation (c) above, R a1 L4 and L5 represent hydrogen atoms or alkyl groups with 1 to 20 carbon atoms, respectively; L4 and L5 represent single bonds or alkylene groups with 1 to 8 carbon atoms, respectively; G1 and G2 represent divalent cyclic groups, respectively; and T4 represents a terminal group. n represents an integer from 0 to 4. When n represents an integer from 2 to 4, two or more L5s can be the same or different, and two or more G2s can be the same or different.

[0237] Regarding the alkylene groups represented by L4 and L5, one or more -CH2- groups constituting the alkylene group can be selected from single bonds, -O-, -S-, and -NR-. 31 -, -C(=O)-, -C(=S)-, -CR 32 =CR 32 -、-C≡C-、-SiR 33 R 34 -、-N=N-、-CR 35 =NN=CR 36 -、-CR 37 =At least one group from the group consisting of N- and -SO2- is substituted, R 31 ~R 37 Each can be independently represented by a hydrogen atom, a halogen atom, a cyano group, a nitro group, or a straight-chain or branched alkyl group having 1 to 10 carbon atoms.

[0238] Furthermore, when L4 or L5 represents an alkylene group, the hydrogen atom contained in one or more -CH2- groups constituting the alkylene group may be substituted by at least one group selected from the group consisting of halogen atoms, cyano, nitro, hydroxyl, straight-chain alkyl groups having 1 to 10 carbon atoms, and branched alkyl groups having 1 to 10 carbon atoms.

[0239] L4 is preferably an alkylene group with 4 to 6 carbon atoms and an oxygen-terminated alkylene group, and L5 is preferably an ester group.

[0240] The divalent cyclic groups represented by G1 and G2 independently represent divalent alicyclic hydrocarbon groups or aromatic hydrocarbon groups with 5 to 8 carbon atoms, and one or more -CH2- atoms constituting the aforementioned alicyclic hydrocarbon group can be replaced by -O-, -S-, or -NH-. Furthermore, the aforementioned divalent cyclic groups can be divalent groups formed by single bonds of multiple groups selected from alicyclic hydrocarbon groups and aromatic hydrocarbon groups. Preferably, a benzene ring is used.

[0241] Examples of terminal groups represented by T4 include hydrogen atoms, halogen atoms, cyano groups, nitro groups, hydroxyl groups, alkyl groups with 1 to 10 carbon atoms, alkoxy groups with 1 to 10 carbon atoms, alkylthio groups with 1 to 10 carbon atoms, alkoxycarbonyloxy groups with 1 to 10 carbon atoms, alkoxycarbonyl groups with 1 to 10 carbon atoms (ROC(O)-: R is an alkyl group with 1 to 10 carbon atoms), acyloxy groups with 1 to 10 carbon atoms, amide groups with 1 to 10 carbon atoms, alkoxycarbonylamino groups with 1 to 10 carbon atoms, sulfonylamino groups with 1 to 10 carbon atoms, aminosulfonyl groups with 1 to 10 carbon atoms, carbamoyl groups with 1 to 10 carbon atoms, sulfinyl groups with 1 to 10 carbon atoms, urea groups with 1 to 10 carbon atoms, and groups containing (meth)acryloyloxy groups. Among these, hydrogen atoms or cyano groups are preferred.

[0242] Regarding the molar ratio of repeating unit F to all repeating units in the above copolymer, from the viewpoint of orientation, it is preferably 50 mol% or more, and from the viewpoint of depression, it is preferably 70 mol% or less.

[0243] (content)

[0244] Considering the reason that the orientation degree of the obtained light absorption anisotropic layer becomes higher, the content of the surfactant is preferably 0.05 to 15 parts by mass relative to 100 parts by mass of the liquid crystal compound, more preferably 0.08 to 10 parts by mass, and even more preferably 0.1 to 5 parts by mass.

[0245] <Polymerization Initiator>

[0246] The composition for forming anisotropic light-absorbing layers preferably contains a polymerization initiator.

[0247] There are no particular restrictions on the use of polymerization initiators, but photosensitive compounds, i.e., photopolymerization initiators, are preferred.

[0248] As photopolymerization initiators, a wide variety of compounds can be used without particular limitations. Specific examples of photopolymerization initiators include α-carbonyl compounds (as described in U.S. Patent Nos. 2,367,661 and 2,367,670), azobin ethers (as described in U.S. Patent No. 2,448,828), α-hydrocarbon-substituted aromatic azobin compounds (as described in U.S. Patent No. 2,722,512), polynuclear quinone compounds (as described in U.S. Patent Nos. 3,046,127 and 2,951,758), and combinations of triarylimidazolium dimers and p-aminophenyl ketones (as described in U.S. Patent No. 3,549,367). ( ), acridine and phenazine compounds (Japanese Patent Application Publication No. 60-105667 and US Patent No. 4239850), oxadiazole compounds (US Patent No. 4212970), o-acyl oxime compounds (Japanese Patent Application Publication No. 2016-027384

[0065] paragraph), and acylphosphine oxide compounds (Japanese Patent Application Publication No. 63-040799, Japanese Patent Application Publication No. 5-029234, Japanese Patent Application Publication No. 10-095788 and Japanese Patent Application Publication No. 10-029997).

[0249] Commercially available products can also be used as photopolymerization initiators. Examples of commercially available photopolymerization initiators include Irgacure 184, Irgacure 907, Irgacure 369, Irgacure 651, Irgacure 819, Irgacure OXE-01, and Irgacure OXE-02 manufactured by BASF.

[0250] When the composition for forming anisotropic light-absorbing layers includes a polymerization initiator, the content of the polymerization initiator is preferably 0.01 to 30 parts by mass, more preferably 0.1 to 15 parts by mass, relative to the total 100 parts by mass of the dichroic substance and the polymeric liquid crystal compound in the composition. When the content of the polymerization initiator is 0.01 parts by mass or more, the durability of the anisotropic light-absorbing film becomes better; when it is 30 parts by mass or less, the orientation degree of the anisotropic light-absorbing film becomes better.

[0251] A polymerization initiator can be used alone or in combination with two or more. When two or more polymerization initiators are used, it is preferable that their total amount is within the range described above.

[0252] <Solvent>

[0253] From an operational point of view, the composition for forming anisotropic light-absorbing layers preferably contains a solvent.

[0254] Examples of solvents include ketones (e.g., acetone, 2-butanone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, etc.), ethers (e.g., dioxane, tetrahydrofuran, 2-methyltetrahydrofuran, cyclopentyl methyl ether, tetrahydropyran, dioxolane, etc.), aliphatic hydrocarbons (e.g., hexane, etc.), alicyclic hydrocarbons (e.g., cyclohexane, etc.), aromatic hydrocarbons (e.g., benzene, toluene, xylene, trimethylbenzene, etc.), halogenated carbons (e.g., dichloromethane, trichloromethane, dichloroethane, dichlorobenzene, chlorotoluene, etc.), and esters (e.g., ethyl acetate). Organic solvents such as methyl esters, ethyl acetate, butyl acetate, ethyl lactate, etc.), alcohols (e.g., ethanol, isopropanol, butanol, cyclohexanol, isoamyl alcohol, neopentyl alcohol, diacetone alcohol, benzyl alcohol, etc.), cellosols (e.g., methyl cellosol, ethyl cellosol, 1,2-dimethoxyethane, etc.), cellosol acetates, sulfoxides (e.g., dimethyl sulfoxide, etc.), amides (e.g., dimethylformamide, dimethylacetamide, N-methylpyrrolidone, N-ethylpyrrolidone, etc.), and heterocyclic compounds (e.g., pyridine, etc.) as well as water.

[0255] One solvent can be used alone, or two or more solvents can be used at the same time.

[0256] Among these solvents, from the viewpoint of utilizing the excellent solubility, ketones (especially cyclopentanone or cyclohexanone), ethers (especially tetrahydrofuran, cyclopentyl methyl ether, tetrahydropyran or dioxolane) or amides (especially dimethylformamide, dimethylacetamide, N-methylpyrrolidone or N-ethylpyrrolidone) are preferred.

[0257] When the composition for forming anisotropic light-absorbing layers contains a solvent, the solvent content relative to the total mass of the composition for forming anisotropic light-absorbing layers is preferably 80 to 99% by mass, more preferably 83 to 97% by mass, and particularly preferably 85 to 95% by mass.

[0258] One solvent may be used alone, or two or more solvents may be used in combination. When two or more solvents are used, it is preferable that their total amount is within the range described above.

[0259] There is no particular limitation on the thickness of the light-absorbing anisotropic layer. From the viewpoint of making the optical element thinner, it is preferably 100 to 8000 nm, and more preferably 300 to 5000 nm.

[0260] <<Orientation Membrane>>

[0261] Polarizer A may also have an alignment film. From the viewpoint of the orientation of the absorption axis of the light absorption anisotropy layer, it is preferable to have an alignment film.

[0262] As an alignment film, there are no particular restrictions as long as it is a film with alignment function, but photoalignment films are preferred.

[0263] There are no particular restrictions on the optical alignment film that polarizer A can have, as long as it is an alignment film that produces an alignment function through light irradiation; any known optical alignment film can be used.

[0264] There are no particular limitations on the materials used to form the photoalignment film, and photoalignment agents can be cited as examples. For instance, a photoalignment film forming composition containing a photoalignment agent can be used to form the photoalignment film.

[0265] A photoorientation agent is a compound having photoorientation groups. As a compound having photoorientation groups, it can be a polymer having repeating units containing photoorientation groups.

[0266] The aforementioned photoorientation groups are functional groups capable of imparting anisotropy to a film through light irradiation. More specifically, these groups are functional groups whose molecular structure can be altered by light irradiation (e.g., linearly polarized light). Typically, they refer to groups that, upon irradiation with light (e.g., linearly polarized light), induce at least one photoreaction selected from photoisomerization, photodimerization, and photodecomposition.

[0267] Among these photo-oriented groups, groups that induce photoisomerization (groups with photoisomerization structures) or groups that induce photodimerization (groups with photodimerization structures) are preferred, and groups that induce photodimerization are more preferred.

[0268] The aforementioned photoisomerization reaction refers to a reaction that uses light to induce stereoisomerization or structural isomerization. As substances that can induce this photoisomerization reaction, for example, substances with an azobenzene structure are known (K. Ichimura et al., Mol. Cryst. Liq. Cryst., 298, p. 221 (1997)), substances with an hydrazine-β-ketoester structure (S. Yamamura et al., Liquid Crystals, Vol. 13, No. 2, p. 189 (1993)), substances with a stilbene structure (JGVictor and JMTorkelson, Macromolecules, 20, p. 2241 (1987)), groups with a cinnamic acid (cinnamyl) structure (skeleton), and substances with a spiropyran structure (K. Ichimura et al., Chemical Letters, p. 1063 (1992); K. Ichimura et al., Solid Films, Vol. 235, p. 101 (1993)).

[0269] The group that initiates the above-mentioned photoisomerization reaction is preferably a group containing a C=C bond or an N=N bond that initiates the photoisomerization reaction. Examples of such groups include groups having an azobenzene structure (skeleton), groups having a hydrazine-β-ketoester structure (skeleton), groups having a stilbene structure (skeleton), groups having a cinnamic acid (cinnamoyl) structure (skeleton), and groups having a spiropyran structure (skeleton). Among these groups, groups having a cinnamoyl structure or a coumarin structure are preferred, and groups having a cinnamoyl structure are more preferred.

[0270] The aforementioned photodimerization reaction refers to the addition reaction between two groups caused by the action of light, typically referring to the reaction that forms a ring structure. Examples of substances that can induce this photodimerization include those with a cinnamic acid structure (M. Schadt et al., J. Appl. Phys., Vol. 31, No. 7, p. 2155 (1992)), those with a coumarin structure (M. Schadt et al., Nature., Vol. 381, p. 212 (1996)), those with a chalcone structure (Ogawa et al., Liquid Crystal Symposium Proceedings, 2AB03 (1997)), and those with a benzophenone structure (YK Jang et al., SID Int. Symposium Digest, p. 53 (1997)).

[0271] Examples of groups that can initiate the aforementioned photodimerization reaction include groups having a cinnamic acid (cinnamoyl) structure (skeleton), groups having a coumarin structure (skeleton), groups having a chalcone structure (skeleton), groups having a benzophenone structure (skeleton), and groups having an anthracene structure (skeleton). Among these groups, groups having a cinnamoyl structure or a coumarin structure are preferred, and groups having a cinnamoyl structure are more preferred.

[0272] Furthermore, compounds having the aforementioned photo-orientation groups preferably also have cross-linking groups.

[0273] As the aforementioned crosslinking group, the preferred crosslinking groups are thermal crosslinking groups that cause curing reactions through heat or photocrosslinking groups that cause curing reactions through light. Alternatively, the crosslinking group may be one that possesses both thermal and photocrosslinking properties.

[0274] Examples of crosslinking groups include at least one group selected from the group consisting of epoxy groups, oxetyl groups, -NH-CH2-OR groups (where R represents an alkyl group having 1 to 20 hydrogen atoms), free radical polymerizable groups (groups having olefinic unsaturated double bonds), and terminal isocyanate groups. Preferably, epoxy groups, oxetyl groups, or groups having olefinic unsaturated double bonds are used.

[0275] In addition, the cyclic ether group of a 3-membered ring is also called an epoxy group, and the cyclic ether group of a 4-membered ring is also called an oxobutyl group.

[0276] Furthermore, examples of free radical polymerizable groups (groups having olefinic unsaturated double bonds) include vinyl, allyl, styrene, acryloyl, and methacryloyl, with acryloyl or methacryloyl being preferred.

[0277] As one of the preferred methods for the aforementioned photoalignment film, a photoalignment film formed using a composition for forming a photoalignment film containing polymer A, wherein polymer A has repeating units a1 containing cinnamic acid groups can be cited.

[0278] In this specification, cinnamic acid group refers to a group having a cinnamic acid structure comprising cinnamic acid or its derivatives as a basic skeleton, and refers to a group represented by formula (I) or formula (II) below.

[0279] [Chemical Formula 10]

[0280]

[0281]

[0282] In the formula, R 1 R represents a hydrogen atom or a monovalent organic group. 2 This represents a monovalent organic group. In formula (I), a represents an integer from 0 to 5, and in formula (II), a represents 0 to 4. When a is 2 or more, multiple R... 1 They can be the same or different. * indicates a connector.

[0283] Regarding polymer A, there are no particular restrictions as long as it is a polymer having repeating unit a1 containing cinnamic acid groups, and conventionally known polymers can be used.

[0284] The weight-average molecular weight of polymer A is preferably 1,000 to 500,000, more preferably 2,000 to 300,000, and even more preferably 3,000 to 200,000.

[0285] Here, the weight-average molecular weight is defined as the polystyrene (PS) conversion value determined by gel permeation chromatography (GPC). The GPC-based determination in this invention can be performed using an HLC-8220GPC (manufactured by Tosoh Corporation) and TSKgel Super HZM-H, HZ4000, and HZ2000 columns.

[0286] As a repeating unit a1 containing a cinnamic acid group in the polymer A described above, for example, the repeating unit represented by the following formulas (A1) to (A4) can be cited.

[0287] [Chemical Formula 11]

[0288]

[0289] Here, in equations (A1) and (A3), R 3 Representing a hydrogen atom or a methyl group, in formulas (A2) and (A4), R 4 Alkyl groups having 1 to 6 carbon atoms.

[0290] In equations (A1) and (A2), L 1 Indicates a single bond or a divalent linker group, where 'a' represents an integer from 0 to 5, and 'R' represents a linker group. 1 It represents a hydrogen atom or an organic group with a valence of 1.

[0291] In equations (A3) and (A4), L 2 R represents a divalent linker group. 2 This represents an organic group with a monovalent valence.

[0292] Furthermore, as L 1 For example, -CO-O-Ph-, -CO-O-Ph-Ph-, and -CO-O-(CH2) can be cited. n -、-CO-O-(CH2) n -Cy- and -(CH2) n -Cy- etc. Here, Ph represents a divalent benzene ring that may have substituents (e.g., phenylene, etc.), Cy represents a divalent cyclohexane ring that may have substituents (e.g., cyclohexane-1,4-diyl, etc.), and n represents an integer from 1 to 4.

[0293] Furthermore, as L 2 For example, -O-CO- and -O-CO-(CH2) can be cited. m -O- etc. Here, m represents an integer from 1 to 6.

[0294] Furthermore, as R 1The monovalent organic group can be, for example, a chain or cyclic alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms that can have substituents.

[0295] Furthermore, as R 2 The monovalent organic group can be, for example, a chain or cyclic alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms and a substituent.

[0296] Furthermore, a is preferably 1, R 1 Preferred alignment.

[0297] Furthermore, examples of substituents that can be present in the aforementioned Ph, Cy, and aryl groups include alkyl, alkoxy, hydroxyl, carboxyl, and amino groups.

[0298] From the viewpoint that the orientation of the light-absorbing anisotropic layer is further improved and the adhesion of the light-absorbing anisotropic layer is further improved, the polymer A preferably further comprises a repeating unit a2 containing a crosslinking group.

[0299] The definition and preferred method of crosslinking groups are as described above.

[0300] Among them, the repeating unit a2 containing crosslinking groups is preferably a repeating unit having an epoxy group, an oxocyclobutyl group, or a group containing an olefinic unsaturated double bond.

[0301] Preferred examples of repeating units having epoxy groups, oxocyclic butyl groups, or groups containing olefinic unsaturated double bonds include the repeating units described below. Additionally, R... 3 and R 4 Compare with the above equation (A1) and R in equation (A1) respectively. 3 and R 4 The meanings are the same.

[0302] [Chemical Formula 12]

[0303]

[0304] The polymer A described above may have other repeating units besides the repeating units a1 and a2 described above.

[0305] Monomers that form other repeating units include, for example, acrylate compounds, methacrylate compounds, maleimide compounds, acrylamide compounds, acrylonitrile, maleic anhydride, styrene compounds, and vinyl compounds.

[0306] When the organic solvent described below is included, the content of the above-mentioned polymer A in the composition for forming the photo-aligned film is preferably 0.1 to 50 parts by mass relative to 100 parts by mass of the organic solvent, more preferably 0.5 to 10 parts by mass.

[0307] From the viewpoint of operability in manufacturing photo-aligned films, the composition for forming photo-aligned films preferably contains a solvent. Examples of solvents include water and organic solvents. Examples of organic solvents include those that can be included in the aforementioned composition for forming anisotropic light-absorbing layers.

[0308] One solvent can be used alone, or two or more solvents can be used at the same time.

[0309] The composition for forming photo-aligned films may contain other components besides those described above. Examples of such other components include, for instance, acid-generating agents, crosslinking catalysts, adhesion modifiers, leveling agents, surfactants, and plasticizers.

[0310] The method for forming a photoalignment film using a composition for forming a photoalignment film will be described later.

[0311] Polarizer A can have other alignment films besides the optical alignment film.

[0312] Other types of orientation films include those formed by methods such as friction treatment of the film surface of an organic compound (preferably a polymer), tilted evaporation of an inorganic compound, formation of a layer with microgrooves, and accumulation of organic compounds (e.g., ω-trisanoic acid, dioctadecylmethylammonium chloride, methyl stearate, etc.) based on the Langmuir Blodgett process (LB film), as well as orientation films that acquire orientation functions by applying an electric field or a magnetic field.

[0313] When polarizer A has an alignment film, there is no particular limitation on its thickness, which is preferably 100 to 2000 nm, and more preferably 400 to 1000 nm.

[0314] <<Manufacturing Method of Polarizer A>>

[0315] Regarding the manufacturing method of polarizer A, there are no particular restrictions as long as polarizer A has a curved surface and the absorption axis is oriented in a way that allows the position Z that satisfies a specific requirement to appear, and known manufacturing methods can be applied.

[0316] As a more specific method for manufacturing polarizer A, for example, the following method can be described: after forming a photo-alignment film on the surface of a resin substrate, a photo-absorbing anisotropic layer is formed on the surface of the formed photo-alignment film using the above-described composition for forming a photo-absorbing anisotropic layer.

[0317] <Methods for forming photo-aligned films>

[0318] There are no particular limitations on the method for forming the photo-alignment film. For example, a manufacturing method having the following steps can be cited: a coating step in which the above-mentioned photo-alignment film forming composition is coated on the surface of a resin substrate to form a coated film; and a light irradiation step in which the coated film of the photo-alignment film forming composition is irradiated with polarized light or unpolarized light to form a photo-alignment film.

[0319] The coating process is a process of applying a composition for photo-alignment film formation onto the surface of a resin substrate to form a coated film.

[0320] There are no limitations on the coating method for the composition used to form the photo-aligned film. Examples include roller coating, gravure printing, spin coating, wire rod coating, extrusion coating, direct gravure coating, reverse gravure coating, die coating, spray coating, and inkjet coating.

[0321] A photo-aligned film is formed by irradiating a coated film formed through a coating process with polarized or unpolarized light.

[0322] Furthermore, when polarized light is irradiated during the light irradiation process, the irradiation direction can be either the normal direction to the coating film surface or a direction inclined relative to the coating film surface. When unpolarized light is irradiated during the light irradiation process, the irradiation direction is an inclined direction relative to the coating film surface.

[0323] The light source used for the light irradiation process can be any light source such as infrared, visible light or ultraviolet light, but ultraviolet light is preferred.

[0324] In the light irradiation process, it is preferable to irradiate the coating film with ultraviolet light (hereinafter also referred to as "polarized UV") whose polarization axis orientation varies depending on the area through which the coating film passes. More preferably, the coating film of the curved light-aligning film forming composition is irradiated with the polarized UV so that the absorption axis of the polarizer A is positioned such that position Z, which satisfies the aforementioned specific requirement, exists.

[0325] As a method for forming a coating film of a curved photo-alignment film forming composition, the following methods can be cited: a method for forming a coating film of a photo-alignment film forming composition on the surface of a resin substrate that is formed into a curved shape; and a method for forming a laminate of a resin substrate and a coating film of a photo-alignment film forming composition into a curved shape by means of a curved surface forming process described later after forming a coating film of a planar resin substrate.

[0326] Furthermore, as a method for irradiating polarized UV light, for example, the following method can be used: passing ultraviolet light through a lens having a convex surface disposed on the light source side closer to the ultraviolet light than the aforementioned coating film, changing the orientation of the polarization axis of the ultraviolet light after passing through the lens according to the position of the lens and the focal distance, thereby irradiating ultraviolet light with different polarization axis orientations according to the position of the aforementioned coating film.

[0327] By subjecting the coated film to the aforementioned light irradiation process, an orientation film is formed with curved portions and multiple regions having orientation limiting forces in different directions.

[0328] <Methods for forming anisotropic light absorption layers>

[0329] There are no particular limitations on the method for forming the light absorption anisotropic layer. For example, a method can be described that sequentially includes the following steps: a step of coating a light absorption anisotropic layer forming composition described above onto the surface of a light alignment film formed in the above-mentioned photoalignment film forming step to form a coated film (hereinafter also referred to as the "coating film forming step"); and a step of aligning the liquid crystal components and / or dichroic substances contained in the coated film (hereinafter also referred to as the "alignment step").

[0330] Furthermore, the liquid crystal component includes not only the aforementioned liquid crystal compound, but also, where the aforementioned dichroic material exhibits liquid crystal properties, a dichroic material exhibiting liquid crystal properties. Moreover, other alignment films described above can be used instead of the photoalignment film to form the light absorption anisotropic layer.

[0331] (Coating film formation process)

[0332] The coating film formation process is a process of coating a substrate with a light-absorbing anisotropic layer forming composition onto the surface of the light-aligned film side to form a coating film.

[0333] By using a composition for forming anisotropic light-absorbing layers containing the aforementioned solvent and / or a liquid such as a heated melt of the composition for forming anisotropic light-absorbing layers, it becomes easier to coat the surface of a light-aligned film with the composition for forming anisotropic light-absorbing layers.

[0334] Coating methods for compositions used to form anisotropic light-absorbing layers include, for example, known methods such as roller coating, gravure printing, spin coating, wire-wound bar coating, extrusion coating, direct gravure coating, reverse gravure coating, die coating, spray coating, and inkjet coating.

[0335] Among them, a spraying method is preferred, which forms a coating film of a light-absorbing anisotropic layer forming composition by spraying a coating liquid composed of a light-absorbing anisotropic layer forming composition.

[0336] Spray coating is a method of applying a coating liquid by spraying it in the form of tiny droplets from a nozzle onto the object being coated. Types of nozzles include single-fluid nozzles and two-fluid nozzles, and either type can be used. Regarding nozzle shape, various shapes exist depending on the spray volume and spray pattern (fan-shaped, columnar, or spray pattern), and any type can be used. In spray coating, the thickness of the coating film can be controlled by adjusting the coating liquid concentration, the coating amount, and the distance between the substrate and the nozzle. For example, if the coating liquid concentration is the same, a thicker coating film is obtained by applying a larger coating amount or a shorter distance between the substrate and the nozzle.

[0337] When spraying a substrate with a curved surface or a substrate with a photo-aligned film (hereinafter also referred to as a "stereoscopic substrate"), it is preferable to place the stereoscopic substrate, which serves as a mold, on a rotary worktable, or to use a rotary chuck to vacuum-adsorb the stereoscopic substrate, thereby performing spraying while rotating the stereoscopic substrate.

[0338] (Orientation process)

[0339] The alignment process is the process of orienting the liquid crystal components contained in the coated film. As a result, an anisotropic light absorption layer can be obtained.

[0340] The orientation process may include a drying process. This drying process removes components such as solvents from the coated film. The drying process can be performed by placing the coated film at room temperature for a specified time (e.g., natural drying), or by heating and / or air supply.

[0341] Here, the liquid crystal components contained in the composition for forming anisotropic light absorption layers are sometimes oriented through the above-described coating film forming process or drying process. For example, in the case where the composition for forming anisotropic light absorption layers is prepared as a coating liquid containing a solvent, the solvent can be removed from the coating film by drying the coating film, thereby obtaining a coating film with anisotropic light absorption (i.e., anisotropic light absorption film).

[0342] If the drying process is performed at a temperature above the transition temperature at which the liquid crystal components contained in the coated film transform into the liquid crystal phase, the heating process described later may not be necessary.

[0343] From the perspective of manufacturing applicability, the transition temperature of the liquid crystal component contained in the coating film to the liquid crystal phase is preferably 10 to 250°C, more preferably 25 to 190°C. If the transition temperature is 10°C or higher, cooling treatment to lower the temperature to the liquid crystal phase temperature range is not required, which is therefore preferable. Furthermore, if the transition temperature is 250°C or lower, high temperatures are not required when setting the isotropic liquid state to a temperature higher than the temporary liquid crystal phase temperature range, thereby reducing heat waste, substrate deformation, and deterioration, which is also preferable.

[0344] The alignment process preferably includes a heat treatment. This allows the liquid crystal components contained in the coated film to be aligned, thus enabling the heat-treated coated film to be preferably used as a light-absorbing anisotropic film.

[0345] From the perspective of manufacturing applicability, the heat treatment is preferably 10 to 250°C, more preferably 25 to 190°C. Furthermore, the heating time is preferably 1 to 300 seconds, more preferably 1 to 60 seconds.

[0346] The alignment process can include a cooling process performed after the heat treatment. The cooling process involves cooling the heated coating film to approximately room temperature (20–25°C). This helps to fix the alignment of the liquid crystal components contained in the coating film. There are no particular limitations on the cooling method, and known methods can be used.

[0347] Through the above processes, an anisotropic light-absorbing film can be obtained.

[0348] Furthermore, in this method, drying treatment and heat treatment are cited as methods for aligning the liquid crystal components contained in the coating film, but it is not limited to these, and can be implemented by known alignment treatments.

[0349] (Other processes)

[0350] The method for forming the light-absorbing anisotropic layer may include a step (hereinafter also referred to as the "curing step") after the above-mentioned orientation step to cure the light-absorbing anisotropic layer.

[0351] For example, when the light-absorbing anisotropic layer has cross-linking groups (polymeric groups), the curing process is carried out by heating and / or light irradiation (exposure). The curing process is preferably carried out by light irradiation.

[0352] The light source used for curing can be various light sources such as infrared, visible light, or ultraviolet light, with ultraviolet light being preferred. Furthermore, during curing, ultraviolet light can be irradiated while heating is being performed, or ultraviolet light can be irradiated through a filter that transmits only a specific wavelength.

[0353] When exposure is performed while heating, although the heating temperature during exposure also depends on the transition temperature of the liquid crystal components contained in the liquid crystal film into the liquid crystal phase, it is preferably 25 to 140°C.

[0354] Furthermore, exposure can also be performed in a nitrogen environment. When curing liquid crystal films via free radical polymerization, the polymerization hindrance caused by oxygen is reduced, therefore exposure in a nitrogen environment is preferred.

[0355] <Surface Forming Process>

[0356] The manufacturing method of polarizer A preferably further includes the following step: forming a component in a group consisting of a planar substrate, a laminate having a planar substrate, and a planar polarizer into a curved surface by thermoforming or vacuum forming (hereinafter also referred to as "curved surface forming step").

[0357] As a method for forming the above-mentioned components into a curved shape, examples include insert molding as described in Japanese Patent Application Publication No. 2004-322501, and forming methods such as vacuum forming, injection molding, pressure forming, decompression coating molding, in-mold transfer, and die stamping as described in International Patent Application Publication No. 2010 / 001867 and Japanese Patent Application Publication No. 2012-116094.

[0358] When the above-mentioned component is formed into a curved surface, it is also preferable to heat it. The heating temperature is preferably 80 to 170°C, more preferably 100 to 150°C, and even more preferably 110 to 140°C.

[0359] Furthermore, after preparing a resin substrate with curved surfaces in advance, a light-aligning film and a light-absorbing anisotropic layer, which are formed as needed, can be formed on the resin substrate with curved surfaces to fabricate a polarizer A.

[0360] The preferred method for manufacturing polarizer A is as follows: After forming an alignment film with multiple regions having curved surfaces and orientation-limiting forces in different directions by a method such as forming a photo-alignment film on the surface of the resin substrate, an anisotropic light-absorbing layer is formed on the surface of the obtained alignment film by the aforementioned method for forming an anisotropic light-absorbing layer. In this case, the preferred method for forming the anisotropic light-absorbing layer is to coat the aforementioned composition for forming the anisotropic light-absorbing layer to form the anisotropic light-absorbing layer; more preferably, it is to spray the aforementioned composition for forming the anisotropic light-absorbing layer to form the anisotropic light-absorbing layer.

[0361] The preferred method for manufacturing polarizer A includes the following steps performed sequentially: a coating step, in which a composition for forming a photo-alignment film is coated onto the surface of a planar resin substrate to form a coating film; a curved surface forming step, in which the resin substrate and the coating film are formed into a curved surface; a light irradiation step, in which polarized light or unpolarized light is irradiated onto the curved coating film; a coating film forming step, in which a composition for forming a light-absorbing anisotropic layer is coated (preferably sprayed) onto the surface of the formed photo-alignment film; and an alignment step, in which the liquid crystal components contained in the formed coating film are aligned.

[0362] However, the method of manufacturing polarizer A is not limited to the example described above.

[0363] [Polarizer B]

[0364] There are no particular restrictions on polarizer B as long as it is an absorption polarizer; any known absorption polarizer containing at least a dichroic material can be used.

[0365] As polarizer B, examples include: a polarizer in which a dichroic substance is oriented by stretching a film after dyeing it with a dichroic substance made of polyvinyl alcohol or other polymer resin; and a polarizer similar to polarizer A, having a light-absorbing anisotropic layer that orients the dichroic substance by utilizing the orientation of a liquid crystal compound.

[0366] From the perspectives of availability and improving polarization, a polarizer made by stretching polyvinyl alcohol dyed with iodine is preferred.

[0367] When this optical element is used in an image display device, polarizer B can be stacked on the image display element, such as a liquid crystal display or an organic EL display. In other words, if the image display element has an absorptive polarizer on the visual recognition side, that absorptive polarizer can be used as polarizer B.

[0368] If the image display device does not have an absorptive polarizer, polarizer B can be installed on the visual recognition side of the image display device.

[0369] [Image display device]

[0370] The image display device of the present invention includes at least the optical element and the image display element. Therefore, in an image display device using a reciprocating optical system, including an absorption polarizer with a curved surface portion, ghosting in the image displayed by the image display element can be further suppressed.

[0371] Furthermore, the image display device can incorporate optical components such as wavelength plates (λ / 4 plates and λ / 2 plates, etc.), reflective linear polarizers, reflective circular polarizers, absorptive polarizers other than polarizer A and polarizer B, semi-reflective mirrors, and anti-reflective films.

[0372] [First Implementation]

[0373] A first embodiment of the image display device according to the present invention will be described with reference to the accompanying drawings.

[0374] Figure 4 This is a schematic diagram illustrating the structure of the image display device according to the first embodiment.

[0375] Figure 4 The image display device 20 shown includes a polarizer A100, a reflective linear polarizer 200, a first λ / 4 plate 600, a semi-reflective mirror 300, a second λ / 4 plate 700, a polarizer B400, an image display element 500, and a frame 24. In the image display device 20, there is a position Z on the straight line L that satisfies a specific requirement.

[0376] The optical element in the image display device 20 consists of a polarizer A100, a reflective linear polarizer 200, a first λ / 4 plate 600, a half-reflective mirror 300, a second λ / 4 plate 700, and a polarizer B400.

[0377] As will be described in detail later, in the image display device 20, after the light ray V is reflected by the reflecting linear polarizer 200 and the half-reflecting mirror 300, it is observed as a displayed image at position Z. That is, the light ray V has a reciprocating optical path between the reflecting linear polarizer 200 and the half-reflecting mirror 300.

[0378] In the image display device 20 of this embodiment, by configuring polarizer A100 and polarizer B400 to have a position Z that satisfies a specific requirement, ghosting that occurs in the displayed image observed at position Z can be effectively suppressed.

[0379] The components of the image display device according to this embodiment will be described. Polarizer A and polarizer B are as described above.

[0380] Furthermore, the definitions of positions X, Y, and Z, straight line L, and virtual lines L1 to L4 in the following description of the image display device are the same as those in the optical element described above.

[0381] <λ / 4 board>

[0382] The image display device according to this embodiment includes a first λ / 4 plate and a second λ / 4 plate.

[0383] Furthermore, in this specification, when simply referred to as "λ / 4 plate," it means that the descriptions related to its structure and features can be applied indiscriminately to both the first λ / 4 plate and the second λ / 4 plate.

[0384] The slow axis direction of the λ / 4 plate in the image display device according to this embodiment is set to convert linearly polarized light into circularly polarized light, and then convert circularly polarized light into linearly polarized light.

[0385] A λ / 4 plate (a quarter-wavelength phase retardation plate) only needs to have a phase difference of approximately one-quarter of the wavelength at any wavelength in the visible region. Examples of λ / 4 plates include those with a phase difference of 120–150 nm at a wavelength of 550 nm, and preferably those with a phase difference of approximately 138 nm (138 ± 10 nm) at 550 nm.

[0386] From the viewpoint of suppressing ghosting in displayed images and thus improving display performance such as brightness and color reproduction, a λ / 4 board preferably has anti-wavelength dispersion. Here, anti-wavelength dispersion means that as the wavelength increases, the phase difference at that wavelength also increases.

[0387] As a λ / 4 plate, known λ / 4 plates can be used without limitation; for example, a phase retardation film made of stretched polycarbonate film and a cured liquid crystal compound can be used. From the viewpoint of thinning, a phase retardation film made of a cured liquid crystal compound is preferred.

[0388] The first λ / 4 plate may have a curved surface. Preferably, the first λ / 4 plate has a rotating surface in which the surface on the image display element side is convex and the surface on the visual recognition side is concave, and more preferably, it has a curved surface with a constant radius of curvature.

[0389] When the first λ / 4 plate has a curved surface with a constant radius of curvature, the radius of curvature can be appropriately selected according to the size and application of the optical element and image display device, preferably 20 to 1000 mm, more preferably 30 to 200 mm.

[0390] (slow axis of λ / 4 plate)

[0391] In the image display device according to this embodiment, the slow axis of the first λ / 4 plate is on the straight line connecting position Z and polarizer B, and the angle between the local absorption axis of polarizer A at the intersection with the straight line and the local slow axis of the first λ / 4 plate at the intersection with the straight line is preferably 45°.

[0392] More specifically, the first λ / 4 plate and polarizer A preferably satisfy all of the following requirements.

[0393] • When viewed from the direction extending from line L, the angle between the direction of the absorption axis of polarizer A at position X and the direction of the slow axis of the first λ / 4 plate at the intersection of line L and the first λ / 4 plate is 45°.

[0394] • When viewed from the direction extending from the virtual line L1, the angle between the direction of the absorption axis of polarizer A at the intersection of the virtual line L1 and polarizer A, and the direction of the slow axis of the first λ / 4 plate at the intersection of the virtual line L1 and the first λ / 4 plate is 45°.

[0395] • When viewed from the direction extending from the virtual line L2, the angle between the direction of the absorption axis of polarizer A at the intersection of the virtual line L2 and polarizer A, and the direction of the slow axis of the first λ / 4 plate at the intersection of the virtual line L2 and the first λ / 4 plate is 45°.

[0396] • When viewed from the direction extending from the virtual line L3, the angle between the direction of the absorption axis of polarizer A at the intersection of the virtual line L3 and polarizer A, and the direction of the slow axis of the first λ / 4 plate at the intersection of the virtual line L3 and the first λ / 4 plate is 45°.

[0397] • When viewed from the direction extending from the virtual line L4, the angle between the direction of the absorption axis of polarizer A at the intersection of the virtual line L4 and polarizer A, and the direction of the slow axis of the first λ / 4 plate at the intersection of the virtual line L4 and the first λ / 4 plate is 45°.

[0398] By satisfying all the above requirements through the slow axis in the first λ / 4 plate, ghosting can be effectively suppressed throughout the entire area of ​​the optical element.

[0399] In the image display device according to this embodiment, it is preferable that the relationship between position Z, polarizer A, and the first λ / 4 plate is satisfied throughout the entire area of ​​polarizer B. Specifically, assuming a straight line Lz connecting position Z and polarizer B, when viewed from the direction extending from line Lz, the angle between the direction of the local absorption axis of polarizer A at the intersection with line Lz and the direction of the local slow axis of the first λ / 4 plate at the intersection with line Lz is 45°. Furthermore, satisfying the above relationship throughout the entire area of ​​polarizer B means that for any point existing on the visual recognition side surface of polarizer B, the above relationship is satisfied regardless of where the straight line Lz connecting position Z is drawn. Therefore, ghosting can be more effectively suppressed throughout the entire area of ​​the image displayed by the image display device according to this embodiment.

[0400] Furthermore, in the image display device according to this embodiment, it is preferable that the local slow axis at the intersection of the first λ / 4 plate and the aforementioned straight line on the connection position Z and the polarizer B, and the local slow axis at the intersection of the second λ / 4 plate and the aforementioned straight line are orthogonal to each other.

[0401] More specifically, the first λ / 4 plate and the second λ / 4 plate preferably satisfy all of the following requirements.

[0402] • When viewed from the direction of the extension of line L, the direction of the slow axis of the first λ / 4 plate at the intersection of line L and the first λ / 4 plate is orthogonal to the direction of the slow axis of the second λ / 4 plate at the intersection of line L and the second λ / 4 plate.

[0403] • When viewed from the direction extending from the virtual line L1, the direction of the slow axis of the first λ / 4 plate at the intersection of the virtual line L1 and the first λ / 4 plate is orthogonal to the direction of the slow axis of the second λ / 4 plate at the intersection of the virtual line L1 and the second λ / 4 plate.

[0404] • When viewed from the direction extending from the virtual line L2, the direction of the slow axis of the first λ / 4 plate at the intersection of the virtual line L2 and the first λ / 4 plate is orthogonal to the direction of the slow axis of the second λ / 4 plate at the intersection of the virtual line L2 and the second λ / 4 plate.

[0405] • When viewed from the direction extending from the virtual line L3, the direction of the slow axis of the first λ / 4 plate at the intersection of the virtual line L3 and the first λ / 4 plate is orthogonal to the direction of the slow axis of the second λ / 4 plate at the intersection of the virtual line L3 and the second λ / 4 plate.

[0406] • When viewed from the direction extending from the virtual line L4, the direction of the slow axis of the first λ / 4 plate at the intersection of the virtual line L4 and the first λ / 4 plate is orthogonal to the direction of the slow axis of the second λ / 4 plate at the intersection of the virtual line L4 and the second λ / 4 plate.

[0407] By satisfying all the above requirements through the slow axis of the first λ / 4 plate and the slow axis of the second λ / 4 plate, ghosting can be effectively suppressed throughout the entire area of ​​the optical element.

[0408] In the image display device according to this embodiment, it is preferable that the relationship between position Z, the first λ / 4 plate, and the second λ / 4 plate is satisfied throughout the entire region of the polarizer B. That is, assuming that the connection position Z is perpendicular to the straight line Lz of the polarizer B, when viewed from the direction extending from the straight line Lz, the local slow axis of the first λ / 4 plate at the intersection with the straight line Lz and the local slow axis of the second λ / 4 plate at the intersection with the straight line Lz are orthogonal. Therefore, ghosting can be more effectively suppressed throughout the entire region of the image displayed by the image display device according to this embodiment.

[0409] According to the method for determining the direction of the absorption axis of polarizer A or polarizer B using AxoScan as described in the above [Specific Method for Position Z], a first λ / 4 plate or a second λ / 4 plate is configured instead of polarizer A or polarizer B, thereby enabling the determination of the direction of the slow axis of the λ / 4 plate at the intersection of the straight line L or the virtual lines L1 to L4 with the λ / 4 plate.

[0410] <Reflective Linear Polarizer>

[0411] The image display device according to this embodiment includes a reflective linear polarizer.

[0412] A reflective linear polarizer has the function of reflecting a portion of the light emitted from the image display element, causing it to oscillate within the optical system. From the viewpoint of suppressing ghosting, a reflective linear polarizer preferably has a high degree of polarization.

[0413] As a reflective linear polarizer, known reflective linear polarizers can be used without limitation. For example, the thin film and metal wire grid polarizer formed by stretching a dielectric multilayer film as described in Japanese Patent Application Publication No. 2011-053705 can be cited. As commercially available reflective linear polarizers, reflective polarizers (trade name APF) manufactured by 3M Company and metal wire grid polarizers (trade name WGF) manufactured by Asahi Kasei Corporation are preferred.

[0414] Reflective linear polarizers can have curved surfaces. Preferably, a reflective linear polarizer has a rotating surface with a convex surface on the image display element side and a concave surface on the visual recognition side, and more preferably, a curved surface with a constant radius of curvature.

[0415] When a reflective linear polarizer has a surface with a constant radius of curvature, the radius of curvature can be appropriately selected according to the size and application of the optical element and the image display device, preferably 20 to 1000 mm, more preferably 30 to 200 mm.

[0416] In the image display device according to this embodiment, regarding the reflection axis of the reflective linear polarizer, it is preferable that the local absorption axis of the polarizer A at the intersection of the line connecting position Z and the polarizer B is parallel to the local reflection axis of the reflective linear polarizer at the intersection of the line.

[0417] More specifically, it is preferred that the reflective linear polarizer and polarizer A satisfy all of the following requirements.

[0418] • When viewed from the direction extending from line L, the direction of the absorption axis of polarizer A at position X is parallel to the direction of the reflection axis of the reflective linear polarizer at the intersection of line L and the reflective linear polarizer.

[0419] • When viewed from the direction extending from the virtual line L1, the direction of the absorption axis of polarizer A at the intersection of the virtual line L1 and polarizer A, and the direction of the reflection axis of the reflection linear polarizer at the intersection of the virtual line L1 and the reflection linear polarizer are parallel.

[0420] • When viewed from the direction extending from the virtual line L2, the direction of the absorption axis of polarizer A at the intersection of the virtual line L2 and polarizer A, and the direction of the reflection axis of the reflection linear polarizer at the intersection of the virtual line L2 and the reflection linear polarizer are parallel.

[0421] • When viewed from the direction extending from the virtual line L3, the direction of the absorption axis of polarizer A at the intersection of the virtual line L3 and polarizer A, and the direction of the reflection axis of the reflection linear polarizer at the intersection of the virtual line L3 and the reflection linear polarizer are parallel.

[0422] • When viewed from the direction extending from the virtual line L4, the direction of the absorption axis of polarizer A at the intersection of the virtual line L4 and polarizer A, and the direction of the reflection axis of the reflection linear polarizer at the intersection of the virtual line L4 and the reflection linear polarizer are parallel.

[0423] By satisfying all the above requirements through the local reflection axis in the reflective linear polarizer, ghosting can be effectively suppressed over the entire area of ​​the optical element.

[0424] Furthermore, in the image display device according to this embodiment, it is preferable that the relationship between position Z, polarizer A, and the reflective linear polarizer is satisfied throughout the entire area of ​​polarizer B. That is, assuming a straight line Lz connecting position Z and polarizer B, when viewed from the direction extending from line Lz, the absorption axis of polarizer A at the intersection with line Lz and the reflection axis of the reflective linear polarizer are parallel. Therefore, ghosting can be more effectively suppressed throughout the entire area of ​​the image displayed by the image display device according to this embodiment.

[0425] According to the method for determining the direction of the absorption axis of polarizer A or polarizer B using AxoScan as described in the above [Specific Method for Position Z], a reflective linear polarizer is configured instead of polarizer A or polarizer B, thereby enabling the determination of the direction of the reflection axis of the reflective linear polarizer at the intersection of the straight line L or the virtual lines L1 to L4 with the reflective linear polarizer.

[0426] <Partial Reflector>

[0427] The image display device described in this embodiment includes a semi-reflective mirror.

[0428] There are no particular limitations on what a semi-reflective mirror can be, and known semi-reflective mirrors such as those made by vapor-depositing aluminum onto a glass plate, and those made by vapor-depositing aluminum onto a transparent resin plate made of resins such as polyethylene terephthalate (PET), cyclic olefin polymer (COP), and polymethyl methacrylate (PMMA), can be used.

[0429] There are no particular limitations on the transmittance of the semi-reflective mirror, but it is preferably 50±30%, more preferably 50±10%, and even more preferably 50%.

[0430] A semi-reflective mirror may have a curved surface. Preferably, the semi-reflective mirror has a surface of rotation with a convex surface on the image display element side and a concave surface on the visual recognition side, and more preferably, it has a curved surface with a constant radius of curvature.

[0431] When a semi-reflective mirror has a curved surface with a constant radius of curvature, the radius of curvature can be appropriately selected according to the size and application of the optical element and the image display device, preferably 20 to 1000 mm, more preferably 30 to 200 mm.

[0432] <Image display element>

[0433] As an image display element, known image display elements can be used, such as liquid crystal displays, organic electroluminescent displays, and micro LED (Light Emitting Diode) displays.

[0434] Regarding the frame, there are no particular limitations as long as it is a component that houses and supports the aforementioned optical components; the appropriate shape of the frame should be selected according to the purpose of the image display device. Examples of frame shapes include the shape of goggles, the shape of a pair of eyeglass frames, and the shape of a helmet.

[0435] refer to Figure 4 The specific usage of the image display device involved in this embodiment will be described.

[0436] Furthermore, in the following description and the explanation of how to use the image display device according to the second embodiment described later, the orientation of the local absorption axis of polarizer A at the position where light V is incident on polarizer A is described as "horizontal" and the orientation of the local absorption axis of polarizer B at the position where light V is incident on polarizer B is described as "vertical".

[0437] Furthermore, in the image display device 20, the image display element 500 emits unpolarized light, the slow axis of the λ / 4 plate 700 is set to convert transversely linearly polarized light incident from the image display element 500 side into right-hand circularly polarized light, the slow axis of the λ / 4 plate 600 is set to convert left-hand circularly polarized light incident from the image display element 500 side into longitudinally linearly polarized light, and the reflection axis of the reflecting linear polarizer 200 is set to transverse.

[0438] exist Figure 4 In the image display device 20 shown, the unpolarized light V emitted from the image display element 500 is absorbed in the polarizer B400, where the longitudinal component is absorbed and becomes transversely linearly polarized light, which is then incident on the λ / 4 plate 700.

[0439] Laterally linearly polarized light incident on the λ / 4 plate 700 is converted into right-hand circularly polarized light by the λ / 4 plate 700 and then incident on the half-reflecting mirror 300.

[0440] About half of the right-handed circularly polarized light incident on the semi-reflecting mirror 300 is transmitted through the semi-reflecting mirror 300 and incident on the λ / 4 plate 600, while the remaining about half is reflected.

[0441] Right-hand circularly polarized light incident from the image display element 500 side onto the λ / 4 plate 600 is converted into transversely linearly polarized light by the λ / 4 plate 600 and incident on the reflective linear polarizer 200.

[0442] As described above, since the reflection axis of the reflective linear polarizer 200 is transverse, the transversely polarized light incident on the reflective linear polarizer 200 is reflected by the reflective linear polarizer 200 and, as transversely polarized light, is again incident on the λ / 4 plate 600 from the visual recognition side (position Z side).

[0443] Laterally linearly polarized light incident on the λ / 4 plate 600 from the visual recognition side is converted into right-hand circularly polarized light by the λ / 4 plate 600 and then incident on the semi-reflective mirror 300 again.

[0444] About half of the right-hand circularly polarized light incident on the semi-reflecting mirror 300 is transmitted through the semi-reflecting mirror 300, and the remaining about half is reflected by the semi-reflecting mirror 300 and is incident on the λ / 4 plate 600 for the third time as left-hand circularly polarized light.

[0445] Left-handed circularly polarized light incident on the λ / 4 plate 600 from the image display element 500 side is converted into longitudinally linearly polarized light and incident on the reflective linear polarizer 200.

[0446] Longitudinal linearly polarized light incident on the reflective linear polarizer 200 is transmitted through the reflective linear polarizer 200 and polarizer A100 and reaches the visual recognition side (position Z).

[0447] Thus, in the image display device 20 of this embodiment, the light V emitted from the image display element 500 passes through the reciprocating optical path between the reflective linear polarizer 200 and the half-reflective mirror 300, and is observed as a displayed image at position Z.

[0448] In the image display device 20 according to this embodiment, there is a position Z that satisfies a specific requirement. Therefore, even if the transversely linearly polarized light that is first incident on the reflective linear polarizer 200 is not sufficiently reflected and is transmitted through the reflective linear polarizer 200, the transversely linearly polarized light is absorbed by the polarizer A which has a transverse absorption axis. Thus, the transmission of light that does not pass through the reciprocating optical path can be suppressed, and ghosting can be suppressed in the observed display image.

[0449] In particular, in the image display device 20 according to this embodiment, the closer the image is to the periphery of the image display element 500, the larger the angle between the straight line connecting position Z to the image display area and the straight line L, and the more obvious the effect of suppressing ghosting is in the displayed image obtained from position Z.

[0450] [Second Implementation]

[0451] A second embodiment of the image display device according to the present invention will be described.

[0452] Figure 5 This is a schematic diagram illustrating the structure of the image display device according to the second embodiment.

[0453] Figure 5 The image display device 22 shown includes a polarizer A100, a first λ / 4 plate 600, a reflective circular polarizer 202, a half-reflective mirror 300, a second λ / 4 plate 700, a polarizer B400, an image display element 500, and a frame 24. In the image display device 22, there is a position Z on the straight line L that satisfies a specific requirement.

[0454] The optical element in the image display device 22 consists of polarizer A100, first λ / 4 plate 600, reflective circular polarizer 202, half-reflective mirror 300, second λ / 4 plate 700 and polarizer B400.

[0455] In the image display device 22, light ray V is reflected by the reflecting circular polarizer 202 and the half-reflecting mirror 300, and is observed as a displayed image at position Z. That is, light ray V has a reciprocating optical path between the reflecting circular polarizer 202 and the half-reflecting mirror 300.

[0456] In the image display device 22 according to this embodiment, by configuring polarizer A100 and polarizer B400 to have a position Z that satisfies a specific requirement, ghosting that occurs in the displayed image observed at position Z can be effectively suppressed.

[0457] The components of the image display apparatus according to this embodiment will be described. Polarizer A and polarizer B, the first and second λ / 4 plates, the half-reflector, and the image display element are as described above.

[0458] <Reflective Circular Polarizer>

[0459] The image display device according to this embodiment includes a reflective circular polarizer.

[0460] A reflective circular polarizer is a polarizer that transmits right-handed or left-handed circularly polarized light and reflects circularly polarized light with the opposite rotation direction to the transmitted circularly polarized light. In the image display device according to this embodiment, it has the function of reflecting a portion of the light emitted from the image display element and causing it to oscillate within the optical system. From the viewpoint of suppressing ghosting, the reflective circular polarizer preferably has a high degree of polarization.

[0461] As a reflective circular polarizer, a reflective circular polarizer having a cholesterol-type liquid crystal layer can be cited as an example. A cholesterol-type liquid crystal layer is a layer having a liquid crystal phase (cholesterol-type liquid crystal phase) in which the liquid crystal compound is in a cholesterol-type orientation state. As a reflective circular polarizer having a cholesterol-type liquid crystal layer, a thin film or the like, which is cured to display the state of the cholesterol-type liquid crystal phase, is preferably used.

[0462] When using a reflecting circular polarizer, the light transmitted through it becomes circularly polarized. Therefore, an optical component is placed between polarizer A and the reflecting circular polarizer to convert the circularly polarized light into linearly polarized light; more specifically, a first λ / 4 plate is provided. Thus, the light transmitted through the reflecting circular polarizer is converted into linearly polarized light and incident on polarizer A.

[0463] refer to Figure 5 The specific usage of the image display device involved in this embodiment will be described.

[0464] In the image display device 22, the image display element 500 emits unpolarized light, the slow axis of the λ / 4 plate 700 is set to convert transversely linearly polarized light incident from the image display element 500 side into right-hand circularly polarized light, the slow axis of the λ / 4 plate 600 is set to convert left-hand circularly polarized light incident from the image display element 500 side into longitudinally linearly polarized light, and the reflecting circular polarizer 202 is configured to reflect right-hand circularly polarized light and transmit left-hand circularly polarized light.

[0465] exist Figure 5In the image display device 22 shown, the unpolarized light V emitted from the image display element 500 is absorbed in the polarizer B400, where the longitudinal component is absorbed and becomes transversely linearly polarized light, which is then incident on the λ / 4 plate 700.

[0466] Laterally linearly polarized light incident on the λ / 4 plate 700 is converted into right-hand circularly polarized light by the λ / 4 plate 700 and then incident on the half-reflecting mirror 300.

[0467] About half of the right-handed circularly polarized light incident on the semi-reflecting mirror 300 is transmitted through the semi-reflecting mirror 300 and incident on the λ / 4 plate 600, while the remaining about half is reflected.

[0468] The right-hand circularly polarized light incident on the reflecting circular polarizer 202 is reflected by the reflecting circular polarizer 202 and, as right-hand circularly polarized light, is incident again on the half-reflecting mirror 300.

[0469] About half of the right-hand circularly polarized light incident on the semi-reflecting mirror 300 is transmitted through the semi-reflecting mirror 300, and the remaining about half is reflected by the semi-reflecting mirror 300, becoming left-hand circularly polarized light, which is then incident on the reflecting circular polarizer 202 again.

[0470] Left-handed circularly polarized light incident on the reflecting circular polarizer 202 is transmitted through the reflecting circular polarizer 202 and incident on the λ / 4 plate 600.

[0471] Left-handed circularly polarized light incident on the λ / 4 plate 600 from the image display element 500 side is converted into longitudinally linearly polarized light by the λ / 4 plate 600 and incident on the polarizer A100.

[0472] Longitudinal linearly polarized light incident on polarizer A100 is transmitted through polarizer A100 and reaches the visual recognition side (position Z).

[0473] Thus, in the image display device 22 of this embodiment, the light V emitted from the image display element 500 passes through the reciprocating optical path between the reflective circular polarizer 202 and the half-reflective mirror 300, and is observed as a displayed image at position Z.

[0474] In the image display device 22 according to this embodiment, there exists a position Z that satisfies specific requirements. Therefore, even if the right-hand circularly polarized light that is first incident on the reflecting circular polarizer 202 is not sufficiently reflected and passes through the reflecting circular polarizer 202, the transmitted right-hand circularly polarized light is converted into transversely linearly polarized light by the λ / 4 plate 600 and then absorbed by the polarizer A having a transverse absorption axis. Thus, the transmission of light that does not pass through the reciprocating optical path can be suppressed, and ghosting can be suppressed in the observed displayed image.

[0475] In particular, in the image display device 22 according to this embodiment, the closer the image is to the periphery of the image display element 500, the larger the angle between the straight line connecting position Z to the image display area and the straight line L, and the more obvious the effect of suppressing ghosting is in the displayed image observed from position Z.

[0476] The structure of the image display device involved in this invention is not limited to the embodiments described above.

[0477] Image display devices may have other functional layers besides those described above. Examples of other functional layers include adhesive layers, bonding layers, anti-reflective layers, and protective layers.

[0478] In addition to at least polarizer A, polarizer B, and the image display device, the image display device preferably includes two optical components selected from the group consisting of a reflective linear polarizer, a reflective circular polarizer, and a half-reflective mirror. More preferably, it also includes any one of the reflective linear polarizer and the reflective circular polarizer and a half-reflective mirror.

[0479] There are no particular limitations on the manufacturing method of the image display device; it may include steps such as separately manufacturing the aforementioned optical components and bonding them together with adhesives or bonding agents. Furthermore, for example, it may include a step of transferring optical components formed on a temporary substrate to other optical components.

[0480] Each process can be carried out in accordance with known methods.

[0481] [Applications of image display devices]

[0482] The application of the image display device is not particularly limited, but it is preferred for use as a myopia display because it suppresses ghosting in the displayed image and is easy to miniaturize and thin. More specifically, the image display device described above can be used as an image display device in optical devices such as electronic viewfinders used in virtual reality display devices, augmented reality display devices, digital cameras, optical telescopes, and optical microscopes.

[0483] Example

[0484] The following examples illustrate the features of the present invention in further detail. Furthermore, the materials, amounts, proportions, processing contents, and processing steps shown below can be appropriately modified as long as they do not depart from the spirit of the present invention. Moreover, structures other than those shown below can be used as long as they do not depart from the main spirit of the present invention.

[0485] [Example 1]

[0486] <Fabrication of Photoalignment Film>

[0487] The photo-alignment film forming coating solution PA1 (described later) was continuously coated onto a resin substrate "TECHNOLLOY C001" (polycarbonate / PMMA laminate substrate, 75 μm thick) manufactured by Sumika Acryl Co., Ltd. using a wire-wound bar, thereby forming a coated film. The substrate with the coated film was dried under warm air at 140°C for 120 seconds to obtain a substrate with a photo-alignment film.

[0488] The thickness of the photo-aligned film is 0.3 μm.

[0489]

[0490]

[0491] Polymer PA-1

[0492] [Chemical Formula 13]

[0493]

[0494] Acid-producing agent PAG-1

[0495] [Chemical Formula 14]

[0496]

[0497] Acid-producing agent CPI-110F

[0498] [Chemical Formula 15]

[0499]

[0500] <Formation of Photoalignment Film>

[0501] Referring to Japanese Patent Application Publication No. 2012-116094, the aforementioned substrate with a light alignment film was vacuum-formed on the convex surface of a plano-convex lens (made of optical glass, with a radius of curvature of 100 mm on the convex surface) with a diameter of 40 mm and a focal distance of 200 mm. Then, the substrate with the light alignment film was peeled off from the lens, thereby obtaining a laminate comprising the substrate and the light alignment film having a curved surface portion.

[0502] <Orientation treatment of photo-aligned films>

[0503] Ultraviolet light generated by an ultra-high pressure mercury lamp is incident onto a convex lens with a diameter of 100 mm and a focal distance of 300 mm, thereby focusing the ultraviolet light. Next, a metal wire grid polarizer is placed on the side of the convex lens opposite to the ultra-high pressure mercury lamp, at a distance of 70 mm, thereby polarizing the ultraviolet light into UV light. Furthermore, a light-aligning film with a curved surface, obtained above, is placed 150 mm away from the convex lens, with the convex side of the curved surface facing the ultra-high pressure mercury lamp and the convex lens. The light-aligning film is then subjected to a 10 mJ / cm² intensity. 2 The polarized UV light was used for exposure, and the photo-alignment film was then oriented.

[0504] By aligning the orientation axis of the photo-alignment film using the method described above, a photo-alignment film capable of forming a light absorption anisotropic layer is obtained, namely, the light absorption anisotropic layer has multiple regions on the surface of the photo-alignment film with different absorption axis directions (see reference). Figure 3 When viewed from position Z, the angle between the direction of the absorption axis of polarizer A and the direction of the absorption axis of polarizer B (described later) is 90° over the entire region of polarizer B.

[0505] <Preparation of Compositions for Forming Anisotropic Light Absorption Layers>

[0506] A composition P1 for forming anisotropic light-absorbing layers with the following composition was prepared.

[0507]

[0508] D-1

[0509] [Chemical Formula 16]

[0510]

[0511] D-2

[0512] [Chemical Formula 17]

[0513]

[0514] D-3

[0515] [Chemical Formula 18]

[0516]

[0517] P-1, a polymeric liquid crystal compound [Chemical Formula 19]

[0518]

[0519] Low molecular weight liquid crystal compound M-1 [Chemical Formula 20]

[0520]

[0521] Surfactant F-1

[0522] [Chemical Formula 21]

[0523]

[0524] <The Construction of Polarizer A>

[0525] On the surface of the curved photo-aligned film that has undergone the above-mentioned orientation treatment, the above-mentioned light-absorbing anisotropic layer forming composition is sprayed using an ASAHI SUNACCORPORATION coating machine "rCoater", that is, a coating film forming process is performed, thereby forming a coating layer P1.

[0526] Next, as an orientation process, coating layer P1 is heated at 140°C for 30 seconds, then cooled to room temperature (23°C), and then heated again at 90°C for 60 seconds, and then cooled to room temperature again.

[0527] Then, as a curing process, LED lights are used at an illuminance of 200mW / cm². 2 Under certain irradiation conditions, the coating layer P1 is irradiated with light of a center wavelength of 365nm for 2 seconds, thereby forming a light-absorbing anisotropic layer.

[0528] Thus, an absorption polarizer A was fabricated, which has a substrate, a light-alignment film, and a light-absorbing anisotropic layer, and has a curved surface portion.

[0529] The thickness of the light-absorbing anisotropic layer of the obtained absorptive polarizer A is 1.6 μm.

[0530] <Fabrication and Formation of λ / 4 Plate>

[0531] Referring to Japanese Patent Application Publication No. 2018-010224, a λ / 4 plate with anti-wavelength dispersion was manufactured by curing a liquid crystal composition containing a liquid crystal compound. Next, the manufactured λ / 4 plate was transferred onto the aforementioned resin substrate "TECHNOLLOY C001" using a UV-curable adhesive.

[0532] By vacuum forming the obtained λ / 4 plate with resin substrate according to the method described in <Forming of Photo-alignment Film>, a λ / 4 plate with a curved surface having a shape along the convex surface of a plano-convex lens and a radius of curvature of 100 mm was obtained.

[0533] <Formation of a Reflective Linear Polarizer>

[0534] By vacuum forming a reflective linear polarizer "APF" manufactured by 3M Company according to the method described in <Forming of Optical Orientation Film>, a reflective linear polarizer λ / 4 plate with a curvature radius of 100 mm and a shape along the convex surface of a plano-convex lens was obtained.

[0535] [Manufacturing of image display devices]

[0536] The "Huawei VR Glass," a virtual reality display device manufactured by Huawei Technologies Co., Ltd. that employs a reciprocating optical system, was disassembled, and the lens located on the visual recognition side and the semi-reflective mirror located on the visual recognition side next to the lens were removed. Furthermore, in the "Huawei VR Glass" with the aforementioned lens removed, a λ / 4 plate, an absorption polarizer, and an image display element are arranged sequentially from the visual recognition side.

[0537] Next, an absorptive polarizer A, a reflective linear polarizer, and a λ / 4 plate, fabricated using the methods described above, were sequentially attached to the convex side of a plano-convex lens with a diameter of 40 mm and a focal distance of 200 mm, thereby creating a stacked lens. This stacked lens was then used as the previously removed visual recognition side lens, and a pre-prepared semi-reflective mirror (radius of curvature 100 mm) was used as the previously removed semi-reflective mirror. The Huawei VR Glass was then reassembled to create the virtual reality display device of Example 1.

[0538] The virtual reality display device of Embodiment 1 has Figure 4 The structure shown is as follows. Specifically, in the virtual reality display device of Embodiment 1, an absorptive polarizer A, a reflective linear polarizer, a first λ / 4 plate, a half-reflective mirror, a second λ / 4 plate, an absorptive polarizer B, and an image display element are arranged sequentially from the visual recognition side. The absorptive polarizer A, the first λ / 4 plate, the reflective linear polarizer, and the half-reflective mirror all have curved surfaces, with the concave surface facing the visual recognition side and the convex surface facing the image display element side. Furthermore, the second λ / 4 plate and the absorptive polarizer B are planar.

[0539] The specific method for position Z described above was tested on the virtual reality display device of Embodiment 1, and it was confirmed that a position Z satisfying a specific requirement exists on the straight line L. That is, it was found that in the virtual reality display device of Embodiment 1, when observing the direction of the straight line L and the virtual lines L1 to L4, there exists a position Z where the angle between the absorption axis of polarizer A and the absorption axis of polarizer B is 90°.

[0540] Furthermore, based on the results of the measurements conducted using the aforementioned measurement method, it was found that in the virtual reality display device of Example 1, when observing the straight line L and virtual lines L1 to L4 in various directions from position Z, the absorption axis of polarizer A is parallel to the reflection axis of the reflective linear polarizer, the angle between the absorption axis of polarizer A and the slow axis of the first λ / 4 plate is 45°, and the slow axis of the first λ / 4 plate is orthogonal to the slow axis of the second λ / 4 plate.

[0541] [Comparative Example 1]

[0542] As a comparative example 1, the virtual reality display device "Huawei VR Glass" manufactured by Huawei Technologies Co., Ltd. was used.

[0543] The lens closest to the visual recognition side in the virtual reality display device of Comparative Example 1 (the lens removed in Example 1) is a plano-convex lens with a convex surface on the visual recognition side. On the plano-convex lens, an absorptive polarizer, a reflective linear polarizer, and a λ / 4 plate are arranged sequentially from the visual recognition side.

[0544] That is, in the virtual reality display device of Comparative Example 1, a first absorptive polarizer, a reflective linear polarizer, a first λ / 4 plate, a half-reflector, a second λ / 4 plate, a second absorptive polarizer, and an image display panel are arranged sequentially from the visual recognition side. Furthermore, each absorptive polarizer, each λ / 4 plate, the reflective linear polarizer, and the half-reflector are planar and arranged parallel to each other. Moreover, the absorption axis of each absorptive polarizer is arranged linearly along one direction within the plane.

[0545] The results of observing the virtual reality display device of Comparative Example 1 from the separated position on the convex side of the plano-convex lens show that, in the region intersecting with the vertical lines descending from the observation position to the first and second absorption polarizers, the angle between the absorption axes of the first and second absorption polarizers is 90°. When observing a direction deviating from the aforementioned region from the observation position, the angle between the absorption axes of the first and second absorption polarizers at the intersection of the lines in the aforementioned direction and the absorption axes of the second absorption polarizer at the intersection of the lines in the aforementioned direction is not 90°.

[0546] Furthermore, the specific method for position Z described above was attempted on the virtual reality display device of Comparative Example 1, but the existence of position Z that satisfies the specific requirements could not be confirmed.

[0547] [Echoes of the previous sentence]

[0548] In each of the virtual reality display devices produced, black and white grid patterns were displayed on the image display elements, and the ghosting observed from the visual recognition side was evaluated by the naked eye.

[0549] As a result, in the virtual reality display device of Comparative Example 1, the image of the white display area in a portion of the black display area of ​​the grid pattern was perceived as a ghost, and the grid pattern was not clear. In particular, the ghosting effect was more pronounced when visually recognizing the displayed image in the area near the periphery.

[0550] In contrast, in the virtual reality display device of Example 1, no ghosting caused by stray light was visually detected in the entire area of ​​the lens and the grid pattern was clearly displayed. In the virtual reality display device of Comparative Example 1, the display image in the area near the periphery where the ghosting effect was obvious was also visually detected, just like the central part of the display image.

[0551] Symbol Explanation

[0552] 10 - Optical element; 20, 22, 30 - Image display device; 24 - Frame; 31, 34 - Absorption polarizer; 32 - Reflection polarizer; 33, 300 - Semi-reflective mirror; 35, 500 - Image display element; 100 - Polarizer A; 200 - Reflection linear polarizer; 202 - Reflection circular polarizer; 400 - Polarizer B; 600 - First λ / 4 plate; 700 - Second λ / 4 plate; S, V - Rays.

Claims

1. An optical element comprising: An absorptive polarizer A with a curved section; and Absorption-type polarizer B, Let position X be the position closest to polarizer B on the surface of polarizer A on the polarizer B side, and position Y be the position of the surface of polarizer B on the polarizer A side that is closest to position X. When drawing a straight line L passing through position X and position Y, on line L and when viewing position X from position Y, there exists a position Z that satisfies the following condition at a position further opposite to position X: Requirements: There exist virtual lines L1, L2, L3, and L4 that pass through the position Z and form an angle of 30° with the straight line L. The angle between the line Lp1, projected orthographically onto polarizer B by the virtual line L1, and the line Lp2, projected orthographically onto polarizer B by the virtual line L2, is 90°. The angle between the line Lp2 and the line Lp3, projected orthographically onto polarizer B by the virtual line L3, is 90°. The angle between the line Lp3 and the line Lp4, projected orthographically onto polarizer B by the virtual line L4, is 90°. The angle between the line Lp4 and the line Lp1 is 90°. The angle between the straight line Lp1 and the absorption axis of the polarizer B is 45°. When viewed from the direction extending from the straight line L, the angle between the absorption axis of polarizer A at position X and the absorption axis of polarizer B at position Y is 90°. When viewed from the direction extending from the virtual line L1, the angle between the direction of the absorption axis of polarizer A at the intersection of the virtual line L1 and polarizer A, and the direction of the absorption axis of polarizer B at the intersection of the virtual line L1 and polarizer B, is 90°. When viewed from the direction extending from the virtual line L2, the angle between the direction of the absorption axis of polarizer A at the intersection of the virtual line L2 and polarizer A, and the direction of the absorption axis of polarizer B at the intersection of the virtual line L2 and polarizer B, is 90°. When viewed from the direction extending from the virtual line L3, the angle between the direction of the absorption axis of polarizer A at the intersection of the virtual line L3 and polarizer A, and the direction of the absorption axis of polarizer B at the intersection of the virtual line L3 and polarizer B, is 90°. When viewed from the direction in which the virtual line L4 extends, the angle between the direction of the absorption axis of polarizer A at the intersection of the virtual line L4 and polarizer A, and the direction of the absorption axis of polarizer B at the intersection of the virtual line L4 and polarizer B, is 90°.

2. The optical element according to claim 1, wherein, The polarizer A has regions where the directions of the absorption axes are different from each other.

3. The optical element according to claim 1 or 2, wherein, The polarizer A has a light-absorbing anisotropic layer comprising a liquid crystal compound and a dichroic material.

4. The optical element according to claim 3, wherein, The polarizer A also has an optical alignment film.

5. An image display device comprising an optical element and an image display element as described in any one of claims 1 to 4.

6. The image display device according to claim 5, wherein, Between polarizer A and polarizer B, starting from the polarizer A side, there are sequentially arranged a reflective linear polarizer, a first λ / 4 plate, a half-reflective mirror, and a second λ / 4 plate. When viewed from the direction extending from the straight line L, the direction of the absorption axis of the polarizer A at position X and the direction of the reflection axis of the reflective linear polarizer at the intersection of the straight line L and the reflective linear polarizer are parallel. When viewed from the direction extending from the virtual line L1, the direction of the absorption axis of polarizer A at the intersection of the virtual line L1 and polarizer A, and the direction of the reflection axis of the reflective linear polarizer at the intersection of the virtual line L1 and the reflective linear polarizer are parallel. When viewed from the direction extending from the virtual line L2, the direction of the absorption axis of polarizer A at the intersection of the virtual line L2 and polarizer A, and the direction of the reflection axis of the reflective linear polarizer at the intersection of the virtual line L2 and the reflective linear polarizer are parallel. When viewed from the direction extending from the virtual line L3, the direction of the absorption axis of polarizer A at the intersection of the virtual line L3 and polarizer A, and the direction of the reflection axis of the reflective linear polarizer at the intersection of the virtual line L3 and the reflective linear polarizer are parallel. When viewed from the direction extending from the virtual line L4, the direction of the absorption axis of the polarizer A at the intersection of the virtual line L4 and the polarizer A, and the direction of the reflection axis of the reflective linear polarizer at the intersection of the virtual line L4 and the reflective linear polarizer are parallel.

7. The image display device according to claim 6, wherein, When viewed from the direction extending from the straight line L, the angle between the direction of the absorption axis of the polarizer A at position X and the direction of the slow axis of the first λ / 4 plate at the intersection of the straight line L and the first λ / 4 plate is 45 ± 10°. When viewed from the direction extending from the virtual line L1, the angle between the direction of the absorption axis of the polarizer A at the intersection of the virtual line L1 and the polarizer A, and the direction of the slow axis of the first λ / 4 plate at the intersection of the virtual line L1 and the first λ / 4 plate, is 45 ± 10°. When viewed from the direction extending from the virtual line L2, the angle between the direction of the absorption axis of the polarizer A at the intersection of the virtual line L2 and the polarizer A, and the direction of the slow axis of the first λ / 4 plate at the intersection of the virtual line L2 and the first λ / 4 plate, is 45 ± 10°. When viewed from the direction extending from the virtual line L3, the angle between the direction of the absorption axis of the polarizer A at the intersection of the virtual line L3 and the polarizer A, and the direction of the slow axis of the first λ / 4 plate at the intersection of the virtual line L3 and the first λ / 4 plate, is 45 ± 10°. When viewed from the direction in which the virtual line L4 extends, the angle between the direction of the absorption axis of the polarizer A at the intersection of the virtual line L4 and the polarizer A, and the direction of the slow axis of the first λ / 4 plate at the intersection of the virtual line L4 and the first λ / 4 plate is 45±10°.

8. The image display device according to claim 6 or 7, wherein, When viewed from the direction extending from the line L, the direction of the slow axis of the first λ / 4 plate at the intersection of the line L and the first λ / 4 plate, and the direction of the slow axis of the second λ / 4 plate at the intersection of the line L and the second λ / 4 plate are orthogonal. When viewed from the direction extending from the virtual line L1, the direction of the slow axis of the first λ / 4 plate at the intersection of the virtual line L1 and the first λ / 4 plate is orthogonal to the direction of the slow axis of the second λ / 4 plate at the intersection of the virtual line L1 and the second λ / 4 plate. When viewed from the direction extending from the virtual line L2, the direction of the slow axis of the first λ / 4 plate at the intersection of the virtual line L2 and the first λ / 4 plate is orthogonal to the direction of the slow axis of the second λ / 4 plate at the intersection of the virtual line L2 and the second λ / 4 plate. When viewed from the direction extending from the virtual line L3, the direction of the slow axis of the first λ / 4 plate at the intersection of the virtual line L3 and the first λ / 4 plate is orthogonal to the direction of the slow axis of the second λ / 4 plate at the intersection of the virtual line L3 and the second λ / 4 plate. When viewed from the direction in which the virtual line L4 extends, the direction of the slow axis of the first λ / 4 plate at the intersection of the virtual line L4 and the first λ / 4 plate is orthogonal to the direction of the slow axis of the second λ / 4 plate at the intersection of the virtual line L4 and the second λ / 4 plate.

9. The image display device according to claim 5, wherein, Between polarizer A and polarizer B, starting from the polarizer A side, there are sequentially arranged a first λ / 4 plate, a reflecting circular polarizer, a half-reflecting mirror, and a second λ / 4 plate. When viewed from the direction extending from the straight line L, the angle between the direction of the absorption axis of the polarizer A at position X and the direction of the slow axis of the first λ / 4 plate at the intersection of the straight line L and the first λ / 4 plate is 45 ± 10°. When viewed from the direction extending from the virtual line L1, the angle between the direction of the absorption axis of the polarizer A at the intersection of the virtual line L1 and the polarizer A, and the direction of the slow axis of the first λ / 4 plate at the intersection of the virtual line L1 and the first λ / 4 plate, is 45 ± 10°. When viewed from the direction extending from the virtual line L2, the angle between the direction of the absorption axis of the polarizer A at the intersection of the virtual line L2 and the polarizer A, and the direction of the slow axis of the first λ / 4 plate at the intersection of the virtual line L2 and the first λ / 4 plate, is 45 ± 10°. When viewed from the direction extending from the virtual line L3, the angle between the direction of the absorption axis of the polarizer A at the intersection of the virtual line L3 and the polarizer A, and the direction of the slow axis of the first λ / 4 plate at the intersection of the virtual line L3 and the first λ / 4 plate, is 45 ± 10°. When viewed from the direction in which the virtual line L4 extends, the angle between the direction of the absorption axis of the polarizer A at the intersection of the virtual line L4 and the polarizer A, and the direction of the slow axis of the first λ / 4 plate at the intersection of the virtual line L4 and the first λ / 4 plate is 45±10°.

10. The image display device according to claim 9, wherein, The reflective circular polarizer has a cholesterol-type liquid crystal layer.

11. The image display device according to claim 5 or 6, wherein, The polarizer B is stacked on the image display element.

12. A virtual reality display device comprising the image display device according to any one of claims 5 to 11.

13. An electronic viewfinder comprising the image display device according to any one of claims 5 to 11.

14. A method for manufacturing a polarizer, characterized in that, The polarizer is polarizer A as described in claim 1. The polarizer is an absorption-type polarizer having multiple regions with mutually different absorption axis directions and a curved surface portion. The method for manufacturing the polarizer includes a step of spraying a composition comprising a liquid crystal compound and a dichroic substance onto the surface of an alignment film. The orientation film has a curved surface portion and multiple regions with orientation limiting forces in different directions.

15. The method for manufacturing a polarizer according to claim 14, wherein, It also includes the following processes: After forming a layer of a composition for forming a photoalignment film containing a photoalignment agent on the surface of a resin substrate, the photoalignment agent is oriented by irradiating the layer with linearly polarized ultraviolet light through a lens, thereby forming the alignment film.

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