Optical element and near-eye display

Abstract

The present invention provides: an optical element which is used when an observer observes an image display device that emits polarized light, and with which the occurrence of color unevenness is suppressed when the observer observes the image display device; and a near-eye display. An optical element according to the present invention includes a first retardation layer and a polarizer layer. The first retardation layer has an in-plane retardation of 3000 nm or more at a wavelength of 550 nm. The polarizer layer has a plurality of regions having different absorption axis directions in a plane.

Description

Optical elements, near-eye displays

[0001] This invention relates to an optical element and a near-eye display.

[0002] Conventionally, phase difference layers such as quarter-wave plates have been used to impart optical functions to image display devices. For example, as described in Patent Document 1, when an observer views an image displayed on an image display device that uses a polarizing plate on the light-emitting side through polarizing sunglasses, the screen appears completely black, which is a problem (blackout). It is known that by installing a quarter-wave plate on the light-emitting side of the image display device, the emitted light is made approximately circularly polarized, thereby preventing blackout.

[0003] Japanese Patent Publication No. 2019-174636

[0004] On the other hand, in recent years, there have been cases where image display devices are viewed while wearing various devices such as near-eye displays that contain polarizers that absorb a predetermined polarization, and it is desirable that blackout be suppressed in such cases as well. One method to solve the above problem is to depolarize using a phase difference layer that exhibits high in-plane retardation. In order to evaluate the basic characteristics when using a phase difference layer exhibiting the above characteristics, the inventors investigated the characteristics of a phase difference layer with the above characteristics and a component containing a polarizer used in near-eye displays, etc., and found that when an observer observes an image display device that emits polarization through that component, color unevenness may occur (see Comparative Example 1 described later).

[0005] In view of the above circumstances, the present invention aims to provide an optical element used when an observer observes an image display device that emits polarized light, which suppresses the occurrence of color unevenness when observing the image display device. The present invention also aims to provide a near-eye display.

[0006] The inventors of this invention have diligently conducted research to solve the above problems and have completed the present invention with the following configuration.

[0007] (1) An optical element comprising a first phase difference layer and a polarizer layer, wherein the in-plane retardation of the first phase difference layer at a wavelength of 550 nm is 3000 nm or more, and the polarizer layer has multiple regions in the plane with different absorption axis directions. (2) The optical element according to (1), wherein the polarizer layer comprises a liquid crystal compound and a dichroic substance. (3) The optical element according to (1) or (2), wherein the average visible light transmittance of the polarizer layer is in the range of 40 to 50%. (4) The optical element according to any one of (1) to (3), wherein the polarizer layer comprises a first region with an absorption axis in a first direction and a second region with an absorption axis in a second direction different from the first direction. (5) The optical element according to (4), wherein the first direction and the second direction are orthogonal. (6) The optical element according to (4) or (5), wherein the ratio of the area of ​​the second region to the area of ​​the first region is 4 / 6 to 6 / 4. (7) An optical element according to any one of (4) to (6), wherein the first region and the second region are arranged alternately in a stripe pattern. (8) An optical element according to (7), wherein the widths of the first region and the second region are 0.1 to 2.0 mm. (9) An optical element according to any one of (4) to (8), further having a second phase difference layer on the side of the polarizer layer opposite to the first phase difference layer, wherein the second phase difference layer has a third region with an in-plane slow axis in the third direction and a fourth region with an in-plane slow axis in the fourth direction which is different from the third direction, and when the optical element is observed in the thickness direction, the third region is positioned to overlap with the first region and the fourth region is positioned to overlap with the second region. (10) A near-eye display having an optical element according to any one of (1) to (9).

[0008] According to the present invention, an optical element can be provided for use when an observer observes an image display device that emits polarized light, and which suppresses the occurrence of color unevenness when observing the image display device. Furthermore, according to the present invention, a near-eye display can be provided.

[0009] This is a diagram illustrating the prior art. This is a diagram illustrating the characteristics of the prior art. This is a diagram illustrating the mechanism of color unevenness generation. This is a diagram illustrating the mechanism of color unevenness generation. This is a diagram showing the first embodiment of the optical element of the present invention. This is a diagram showing the polarizer layer included in the first embodiment of the optical element of the present invention. This is a diagram showing the second embodiment of the optical element of the present invention. This is a diagram showing the second phase difference layer included in the second embodiment of the optical element of the present invention.

[0010] The present invention will be described in detail below. The following descriptions of constituent elements may be based on typical embodiments of the present invention, but the present invention is not limited to such embodiments.

[0011] In this specification, numerical ranges expressed using "~" mean a range that includes the numbers before and after "~" as the lower and upper limits. Also, in this specification, if there are two or more types of a component, unless otherwise specified, the "content" of that component means the total content of those two or more components. In this specification, in numerical ranges described in stages, the upper or lower limit stated in one numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Also, in numerical ranges described in this specification, the upper or lower limit stated in one numerical range may be replaced with the values ​​shown in the examples.

[0012] In this specification, "absorption axis" means the polarization direction in which the absorbance is maximum when linearly polarized light is incident on the element. "In-plane lagging axis" means the direction in which the refractive index is maximum. In this specification, "parallel" and "orthogonal" mean that the difference from the exact angle is within 5°.

[0013] In this specification, Re(λ) and Rth(λ) represent the in-plane retardation and thickness retardation at wavelength λ, respectively. Unless otherwise specified, wavelength λ is 550 nm. Furthermore, in this specification, Re(λ) and Rth(λ) are values ​​measured at wavelength λ using AxoScan (manufactured by Axometrics). Specifically, by inputting the average refractive index ((nx + ny + nz) / 3) and film thickness (d) into AxoScan, the following can be calculated: In-plane retardation axis direction (°) Re(λ) = R0(λ) Rth(λ) = ((nx + ny) / 2 - nz) × d Note that R0(λ) is displayed as a numerical value calculated by AxoScan, but it means Re(λ).

[0014] In this specification, the refractive indices nx, ny, and nz are measured using an Abbe refractometer (NAR-4T, manufactured by Atago Corporation) with a sodium lamp (λ = 589 nm) as the light source. Wavelength dependence can be measured using a multi-wavelength Abbe refractometer DR-M2 (manufactured by Atago Corporation) in combination with an interference filter. Values ​​from the Polymer Handbook (JOHN WILEY & SONS, INC.) and catalogs of various optical films can also be used. Examples of average refractive index values ​​for major optical films are given below: cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), and polystyrene (1.59).

[0015] The optical element of the present invention will be described in detail below. The optical element of the present invention has a phase difference layer exhibiting a predetermined in-plane retardation and a phase difference layer having multiple regions with different absorption axis directions in the plane. The reasons why the optical element of the present invention exhibits the desired effect will be described in detail below. First, the prior art will be described in detail. Figure 1 is a diagram considering the case in which an observer observes an image display device while wearing a device including a polarizer, such as a near-eye display. In Figure 1, polarization indicated by a white arrow is emitted from the image display device 100. As described above, when observer OB observes the image display device 100 which emits polarization through a polarizer 104 having an absorption axis in one direction, blackout may occur. Therefore, in order to avoid this problem, a means of observing the image display device 100 through a phase difference layer 102 that exhibits a high in-plane retardation of 3000 nm or more at a wavelength of 550 nm, which is also used in the present invention, is mentioned. Figure 2 is a diagram showing an example of transmittance when visible light is incident on the phase difference layer 102 and the polarizer 104. Because the phase difference layer 102 has very high in-plane retardation, the change in in-plane retardation with respect to each wavelength is large. For example, suppose that when polarized light of a certain wavelength is incident on the phase difference layer 102 and the polarizer 104, the incident polarized light is converted into a polarized light that is absorbed by the polarizer 104 due to the in-plane retardation characteristics of the phase difference layer 102 at that wavelength. In such a case, when polarized light with a wavelength close to the wavelength of the absorbed polarized light is incident on the phase difference layer 102 and the polarizer 104, the in-plane retardation of the phase difference layer 102 changes significantly, so that the light can be transmitted without being absorbed when passing through the phase difference layer 102 and the polarizer 104. In other words, as shown in Figure 2, absorbed wavelengths and transmitted wavelengths appear alternately. Therefore, light of all wavelengths is not cut off, and the blackout problem described above can be resolved.

[0016] On the other hand, the polarization emitted from the image display device 100 does not necessarily contain light of all wavelengths, but is often emitted as light of a narrow band of wavelengths. When light of such a narrow band of wavelengths is emitted, color unevenness is particularly likely to occur. The reason for this will be explained using Figures 3 and 4. Figure 3 is an enlarged view of the transmittance results for a certain wavelength range in Figure 2. If the polarization emitted from the image display device 100 is light of the narrow band spectrum shown by the dashed line in Figure 3, the transmittance is high at this wavelength, so when the image display device 100 is observed from the front, an image with a predetermined color is observed. In contrast, if the observer shifts their line of sight slightly from the front, the optical path length between the image display device 100 and the observer changes, so the transmittance when passing through the phase difference layer 102 and the polarizer 104 changes. Specifically, as shown in Figure 4, the curve showing the transmittance, shown by the solid line, shifts. In such a case, most of the light of the narrow band spectrum shown by the dashed line is absorbed, and the color changes. As a result, when observer OB observes the image display device 100, color unevenness occurs in the observed image.

[0017] In contrast, the optical element of the present invention has a phase difference layer with multiple regions having different absorption axis directions within its plane. In other words, the phase difference layer included in the optical element of the present invention is a so-called pattern polarizer layer. When polarization of a certain wavelength is incident on the optical element of the present invention, even if the transmittance becomes low in some regions of the polarizer layer as shown in Figure 4 above, the transmittance can be increased in other regions with different absorption axis directions as shown in Figure 3 above. The light that has passed through each of these regions reaches the observer, and as a result, an image with averaged colors is observed. Therefore, even if the observer slightly changes their line of sight from the front, the light that has passed through each region reaches the observer as before the line of sight was changed, and an image with averaged colors is observed as before the line of sight was changed, and an image with the same colors as before the line of sight was changed is observed. As a result, it is possible to suppress the occurrence of color unevenness when the observer observes the image display device. In particular, when the polarizer layer has two regions with mutually orthogonal absorption axes, it is possible to maintain a complementary relationship in terms of transmittance, such that if the transmittance of one region is 0%, the transmittance of the other region becomes 100%. Therefore, color unevenness is further suppressed regardless of the angle of the observer's line of sight.

[0018] <<First Embodiment>> Figure 5 shows a first embodiment of the optical element of the present invention. The optical element 10A shown in Figure 5 includes a first phase difference layer 12 and a polarizer layer 14. The polarizer layer 14 includes a first region 16 and a second region 18. As shown in Figure 6, the first region 16 and the second region 18 are arranged in a stripe pattern, and the first region 16 and the second region 18 are arranged alternately. The arrows in the first region 16 and the second region 18 indicate the direction of the absorption axis within each region. The first region 16 has an absorption axis parallel to the direction in which the first region 16 extends, and the second region 18 has an absorption axis parallel to the direction perpendicular to the direction in which it extends. In other words, the absorption axis in the first region 16 and the absorption axis in the second region 18 are perpendicular to each other. The absorption axis of the first region 16 and the absorption axis of the second region 18 are both parallel to the main surface (the surface perpendicular to the thickness direction) of the polarizer layer 14. As described above, when observing the image display device 100 that emits polarized light indicated by the white arrow through the optical element 10A with the above configuration, the light passing through the first region 16 and the light passing through the second region 18 reach the observer, and the observer can observe an image with a color tone that is an average of both. Therefore, the occurrence of color unevenness is suppressed. Each component will be described in detail below.

[0019] <First Phase Difference Layer> The in-plane retardation of the first phase difference layer at a wavelength of 550 nm is 3000 nm. There is no particular upper limit to the above in-plane retardation, but it is preferably 100000 nm or less. In particular, 5000 to 50000 nm is preferred, and 7000 to 20000 nm is more preferred in that color unevenness is further suppressed. When the in-plane retardation is 3000 nm or more, the polarization depolarization ability due to wavelength scrambling is increased, so color unevenness can be suppressed. Also, when the in-plane retardation is 100000 nm or less, the decrease in transmittance and deterioration of transmitted image clarity due to the thickness of the phase difference film being too thick can be suppressed.

[0020] The first phase difference layer may be a single-layer structure or a multi-layer structure, as long as it exhibits the in-plane retardation described above.

[0021] The thickness of the first phase difference layer is not particularly limited, but is often 25 to 1000 μm, and more often 40 to 800 μm.

[0022] The material constituting the first phase difference layer is not particularly limited, and known materials can be used. The first phase difference layer preferably contains a thermoplastic resin (preferably polyester resin or polycarbonate resin). In particular, the first phase difference layer more preferably contains a thermoplastic resin as its main component. The main component refers to the material that constitutes 50% by mass or more of the first phase difference layer.

[0023] The first phase difference layer preferably contains a polyester resin. In particular, the first phase difference layer is preferably a polyester film mainly composed of a polyester resin. Furthermore, it is more preferable that the first phase difference layer is a polyester film stretched in at least one axial direction. Examples of polyester resins include polyethylene terephthalate, polyethylene isophthalate, polyethylene-2,6-naphthalate, polybutylene terephthalate, and 1,4-cyclohexanedimethylene terephthalate, with polyethylene terephthalate or polyethylene-2,6-naphthalate being preferred, and polyethylene terephthalate being more preferred from the viewpoint of material cost. The polyester resin may be used alone or in combination of two or more types.

[0024] Polyethylene terephthalate is a polyester resin having structural units derived from terephthalic acid as a dicarboxylic acid component and structural units derived from ethylene glycol as a diol component. Preferably, 80 mol% or more of the total repeating units of the polyester resin are structural units derived from terephthalic acid and structural units derived from ethylene glycol. The polyester resin may also contain structural units other than those derived from terephthalic acid and structural units derived from ethylene glycol. Examples of other structural units include structural units derived from dicarboxylic acid components such as isophthalic acid, p-β-oxyethoxybenzoic acid, 4,4'-dicarboxydiphenyl, 4,4'-dicarboxybenzophenone, bis(4-carboxyphenyl)ethane, adipic acid, sebacic acid, 5-sodium sulfisoisophthalic acid, and 1,4-dicarboxycyclohexane, as well as structural units derived from diol components such as propylene glycol, butanediol, neopentyl glycol, diethylene glycol, cyclohexanediol, ethylene oxide adduct of bisphenol A, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. Other constituent units can be used in combination of two or more types as needed. In addition, oxycarboxylic acids such as p-oxybenzoic acid may be used together with the above-mentioned carboxylic acid and diol components.

[0025] Methods for producing polyethylene terephthalate include the so-called direct polymerization method, in which terephthalic acid is directly reacted with ethylene glycol and, if necessary, other components (e.g., other dicarboxylic acids and other diols), and the so-called transesterification method, in which dimethyl ester of terephthalic acid is transesterified with ethylene glycol and, if necessary, other components (e.g., dimethyl ester of other dicarboxylic acids and other diols).

[0026] The first phase difference layer may also preferably contain a polycarbonate resin. In particular, the first phase layer may be a polycarbonate film mainly composed of a polycarbonate resin. Examples of polycarbonate resins include polycarbonate resins having a bisphenol A skeleton, which are obtained by reacting a dihydroxy component with a carbonate precursor by interfacial polymerization or melt polymerization. For example, those described in Japanese Patent Publication No. 2006-277914, Japanese Patent Publication No. 2006-106386, and Japanese Patent Publication No. 2006-284703 can be preferably used. A commercially available product is "Toughlon MD1500" (manufactured by Idemitsu Kosan Co., Ltd.).

[0027] The first phase difference layer may contain an ultraviolet absorber. The ultraviolet absorber is a compound having ultraviolet absorption ability and is not particularly limited as long as it can withstand the heat added during the manufacturing process of the first phase difference layer. Examples of ultraviolet absorbers include organic ultraviolet absorbers and inorganic ultraviolet absorbers, and organic ultraviolet absorbers are preferred from the viewpoint of transparency. Examples of organic ultraviolet absorbers include benzotriazole-based, hydroxyphenyltriazine-based, and benzoxazine-based ultraviolet absorbers. A preferred ultraviolet absorber is 2,2'-(p-phenylene)di-3,1-benzoxazine-4-one (manufactured by Fujifilm Fine Chemicals Co., Ltd., product name UVSORB 101). In addition, two or more ultraviolet absorbers with different maximum absorption wavelengths may be used in combination to broaden the ultraviolet absorption range. The content of the ultraviolet absorber is preferably 0.01 to 20% by mass, and more preferably 0.1 to 15% by mass, based on the total mass of the resin contained in the first phase difference layer.

[0028] There are no particular limitations on the method for manufacturing the first phase difference layer, but in order to impart the above-mentioned properties, it is preferable to manufacture it by the following method. First, the resin to be used for the first phase difference layer (for example, polyester resin) is melt-extruded into a film shape, cooled and solidified in a casting drum to obtain an unstretched film, and then, if necessary, a coating liquid for forming an easy-adhesion layer is applied, and it is preferable to stretch this unstretched film at a temperature of the glass transition temperature of the polyester film to (glass transition temperature + 60) °C so that it is 3 to 10 times, preferably 3 to 7 times, in the width direction. As the first phase difference layer, a polyester film stretched at least in one axial direction is preferred, and a polyester film stretched at least in the width direction is more preferred.

[0029] Next, it is preferable to heat-treat the film obtained above at 140 to 220°C for 1 to 60 seconds (referred to here as heat setting). The heat setting temperature is more preferably 150 to 220°C. Furthermore, it is preferable to reheat-treat the film obtained above at a temperature 10 to 20°C lower than the heat setting temperature while shrinking it by 0 to 20% in the longitudinal and / or widthwise directions (referred to as relaxation treatment). In this method, the film comes into contact with the roll less, making it less likely for minute scratches to form on the film surface, which is advantageous for application in optical applications.

[0030] <Polarizer Layer> The polarizer layer has multiple regions with different absorption axis directions within its plane. In Figures 5 and 6 described above, the first phase difference layer 12 has two regions with different absorption axis directions within its plane, but the present invention is not limited to this embodiment. In other words, the polarizer layer may have three or more regions with different absorption axis directions within its plane. In particular, from a manufacturing standpoint, it is preferable that the phase difference layer has two regions with different absorption axis directions within its plane. That is, it is preferable that the polarizer layer has a first region with an absorption axis in a first direction and a second region with an absorption axis in a second direction which is different from the first direction. It is preferable that both the first and second directions are parallel to the main plane of the polarizer layer (the plane perpendicular to the thickness direction). When the phase difference layer has a first region and a second region, the ratio of the area of ​​the second region to the area of ​​the first region is not particularly limited, but 4 / 6 to 6 / 4 is preferred in that color unevenness is further suppressed.

[0031] In Figures 5 and 6 described above, the absorption axis in the first region 16 and the absorption axis in the second region 18 are orthogonal, but the present invention is not limited to this embodiment. The absorption axis directions in the multiple regions of the phase difference layer do not need to be different from each other. When the phase difference layer has a first region and a second region, the angle between the first direction and the second direction is preferably 90 ± 20° (70 to 110°), more preferably 90 ± 10° (80 to 100°), and even more preferably 90 ± 5° (85 to 95°) in terms of being able to further suppress color unevenness.

[0032] Within the polarizer layer, the arrangement shape of regions with different slow axis directions is not particularly limited. In Figures 5 and 6 described above, the two regions (first region 16 and second region 18) were arranged alternately in a stripe pattern, but the present invention is not limited to this embodiment. For example, regions with different slow axis directions may be arranged in a checkerboard pattern. When the polarizer layer has two regions (first region 16 and second region 18), it is preferable that the two regions are arranged alternately along one direction. In particular, from a manufacturing standpoint, it is preferable that the two regions with different absorption axis directions are arranged alternately in a stripe pattern within the plane.

[0033] When two regions with different absorption axis directions are alternately arranged in a stripe pattern within the polarizer layer, the width of each region is not particularly limited, but is preferably 0.01 to 3.0 mm. In particular, a width of 0.1 mm or more is more preferable, and 0.5 mm or more is even preferable, as it further suppresses image blurring. Furthermore, a width of 2.0 mm or less is more preferable, and 1.5 mm or less is even preferable, as it provides better pattern visibility.

[0034] The average visible light transmittance of the polarizer layer is not particularly limited, but 37-53% is preferred. In particular, 40% or more is more preferred, and 42% or more is even more preferred, as it provides superior brightness. Furthermore, 50% or less is more preferred, and 48% or less is even more preferred, as it suppresses color unevenness. The average visible light transmittance refers to the arithmetic mean of the transmittances in 5 nm increments in the visible light region (wavelength 400-700 nm). A spectrophotometer (for example, a multi-channel spectrometer (OCEAN OPTICS, product name "QE65000")) is used to measure the transmittance.

[0035] The thickness of the polarizer layer is not particularly limited, but in terms of the balance between brightness and color uniformity, 0.1 to 4.0 μm is preferred, and 0.2 to 2.0 μm is more preferred.

[0036] The materials included in the polarizer layer are not particularly limited and include known materials. In particular, from a manufacturing standpoint, it is preferable that the polarizer layer includes a liquid crystal compound and a dichroic substance. In particular, as will be described later, it is preferable that the polarizer layer be formed using a composition containing a liquid crystal compound and a dichroic substance, and more preferably using a composition containing a polymerizable liquid crystal compound and a dichroic substance.

[0037] (Liquid Crystal Compound) As the liquid crystal compound, both high-molecular-weight liquid crystal compounds and low-molecular-weight liquid crystal compounds can be used, and high-molecular-weight liquid crystal compounds are preferable from the viewpoint that a high degree of orientation can be achieved. Further, as the liquid crystal compound, a high-molecular-weight liquid crystal compound and a low-molecular-weight liquid crystal compound may be used in combination. Here, the term "high-molecular-weight liquid crystal compound" refers to a liquid crystal compound having repeating units in its chemical structure. Further, the term "low-molecular-weight liquid crystal compound" refers to a liquid crystal compound having no repeating units in its chemical structure. Examples of the high-molecular-weight liquid crystal compound include thermotropic liquid crystalline polymers described in Japanese Patent Application Laid-Open No. 2011-237513, and high-molecular-weight liquid crystal compounds described in paragraphs

[0012] to

[0042] of International Publication No. WO 2018 / 199096. Examples of the low-molecular-weight liquid crystal compound include liquid crystal compounds described in paragraphs

[0072] to

[0088] of Japanese Patent Application Laid-Open No. 2013-228706, and among them, liquid crystal compounds exhibiting smectic properties are preferable.

[0038] The liquid crystal compound may be fixed in the polarizer layer. Further, the liquid crystal compound in the polarizer layer may no longer exhibit liquid crystallinity. For example, when a polarizer layer is formed using a polymerizable liquid crystal compound, the liquid crystal compound may have its molecular weight increased through a curing reaction and no longer exhibit liquid crystallinity.

[0039] In order to fix the liquid crystal compound in the polarizer layer, for example, a method of using a liquid crystal compound having a polymerizable group (polymerizable liquid crystal compound), aligning the liquid crystal compound, then polymerizing the liquid crystal compound to form the polarizer layer can be mentioned. The polymerizable group is not particularly limited, but a polymerizable group capable of radical polymerization or cationic polymerization is preferable. Examples of the radically polymerizable group include known radically polymerizable groups, and an acryloyl group or a methacryloyl group is preferable. It is generally known that acryloyl groups have a higher polymerization rate, and acryloyl groups are preferable from the viewpoint of improving productivity, but methacryloyl groups can also be similarly used as polymerizable groups for high birefringence liquid crystals.

[0040] The content of the liquid crystal compound is not particularly limited, but from the viewpoint of increasing the degree of orientation of the polarizer layer, the content is preferably 70% by mass or more, and more preferably 90% by mass or more, based on the total mass of the polarizer layer. The upper limit is not particularly limited, and examples thereof include less than 100% by mass. The liquid crystal compounds may be used alone, or two or more kinds thereof may be used in combination. When two or more kinds of liquid crystal compounds are used, the total amount thereof preferably falls within the above range.

[0041] (Dichroic Substance) A dichroic substance means a substance having different absorbance depending on direction. The dichroic substance may or may not exhibit liquid crystallinity.

[0042] Dichroic materials are not particularly limited and include visible light absorbing materials (dichroic dyes), luminescent materials (fluorescent materials, phosphorescent materials), ultraviolet absorbing materials, infrared absorbing materials, nonlinear optical materials, carbon nanotubes, and inorganic materials (e.g., quantum rods). Conventionally known dichroic materials (dichroic dyes) can also be used. Specifically, for example, paragraphs

[0067] to

[0071] of JP 2013-228706, paragraphs

[0008] to

[0026] of JP 2013-227532, paragraphs

[0008] to

[0015] of JP 2013-209367, paragraphs

[0045] to

[0058] of JP 2013-14883, paragraphs

[0012] to

[0029] of JP 2013-109090, paragraphs

[0009] to

[0017] of JP 2013-101328, JP Paragraphs

[0051] to

[0065] of Japanese Patent Publication No. 2013-037353, paragraphs

[0049] to

[0073] of Japanese Patent Publication No. 2012-063387, paragraphs

[0016] to

[0018] of Japanese Patent Publication No. Hei 11-305036, paragraphs

[0009] to

[0011] of Japanese Patent Publication No. 2001-133630, paragraphs

[0030] to

[0169] of Japanese Patent Publication No. 2011-215337, paragraphs

[0021] to

[0075] of Japanese Patent Publication No. 2010-106242, and Japanese Patent Publication No. 2010-215846 Paragraphs

[0011] to

[0025] of Japanese Patent Publication No. 2011-048311, paragraphs

[0017] to

[0069] of Japanese Patent Publication No. 2011-213610, paragraphs

[0013] to

[0133] of Japanese Patent Publication No. 2011-237513, paragraphs

[0074] to

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

[0005] to

[0051] of Japanese Patent Publication No. 2016-006502, paragraphs

[0014] to

[0032] of Japanese Patent Publication No. 2018-053167, and paragraphs

[0014] to

[0033] of Japanese Patent Publication No. 2020-011716. Paragraphs, paragraphs

[0005] to

[0041] of International Publication No. 2016 / 060173, paragraphs

[0008] to

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

[0014] to

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

[0014] to

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

[0013] to

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

[0014] to

[0034] of International Publication No. 2018 / 164252,Examples include paragraphs

[0021] to

[0030] of International Publication No. 2018 / 186503, paragraphs

[0043] to

[0063] of International Publication No. 2019 / 189345, paragraphs

[0043] to

[0085] of International Publication No. 2019 / 225468, paragraphs

[0050] to

[0074] of International Publication No. 2020 / 004106, and paragraphs

[0015] to

[0038] of International Publication No. 2021 / 044843.

[0043] Dichroic azo dye compounds are preferred as the dichroic substance. Dichroic azo dye compounds refer to azo dye compounds whose absorbance differs depending on the direction. Dichroic azo dye compounds may or may not exhibit liquid crystalline properties. If a dichroic azo dye compound exhibits liquid crystalline properties, it may exhibit either nematic or smectic properties. The temperature range in which the liquid crystalline phase is exhibited is preferably room temperature (about 20 to 28°C) to 300°C, and more preferably 50 to 200°C from the viewpoint of handling and manufacturing suitability.

[0044] From the standpoint of color adjustment, it is preferable to use at least one dye compound (first dichroic azo dye compound) having a maximum absorption wavelength in the range of 560 to 700 nm, and at least one dye compound (second dichroic azo dye compound) having a maximum absorption wavelength in the range of 455 nm or more and less than 560 nm.

[0045] In the present invention, three or more dichroic azo dye compounds may be used in combination. For example, from the viewpoint of making the polarizer layer closer to black, it is preferable to use a first dichroic azo dye compound, a second dichroic azo dye compound, and at least one dye compound (third dichroic azo dye compound) having a maximum absorption wavelength in the range of 380 nm to less than 455 nm.

[0046] The dichroic azo dye compound preferably has a crosslinking group. Examples of crosslinking groups include (meth)acryloyl group, epoxy group, oxetanyl group, and styryl group, with (meth)acryloyl group being preferred. The polarizer layer may contain a cured product (crosslinked product) of a dichroic dye having a crosslinking group (particularly a dichroic dye compound having a crosslinking group).

[0047] The content of the dichroic substance is not particularly limited, but from the standpoint of increasing the degree of orientation of the polarizer layer, it is preferably 3% by mass or more, more preferably 8% by mass or more, even more preferably 10% by mass or more, and particularly preferably 10 to 40% by mass, relative to the total mass of the polarizer layer. The dichroic substance may be used alone or in combination of two or more types. When two or more types of dichroic substances are used, it is preferable that their total amount is within the above range.

[0048] (Other components) The polarizer layer may contain components other than those described above. Examples of other components include leveling agents.

[0049] (Method for manufacturing the polarizer layer) The method for manufacturing the polarizer layer is not particularly limited, and known methods can be used. For example, a method comprising the steps of applying a polarizer layer-forming composition containing a liquid crystal compound and a dichroic substance onto a pattern alignment film to form a coating film (hereinafter also referred to as the "coating film formation step") and aligning the liquid crystal compound contained in the coating film (hereinafter also referred to as the "alignment step") in this order is preferred. Each step will be described below.

[0050] The coating film formation step involves applying a polarizer layer formation composition onto a pattern alignment film to form a coating film. The polarizer layer formation composition includes a liquid crystal compound and a dichroic substance. As mentioned above, the liquid crystal compound may be a polymerizable liquid crystal compound. The polarizer layer formation composition may also contain components other than the liquid crystal compound (e.g., solvent, polymerization initiator, etc.).

[0051] Known methods for applying the polarizer layer-forming composition include roll coating, gravure printing, spin coating, wire bar coating, extrusion coating, direct gravure coating, reverse gravure coating, die coating, spray coating, and inkjet coating.

[0052] Pattern alignment films are films that have different alignment control capabilities. Therefore, when liquid crystal compounds are aligned on a pattern alignment film, different alignment states can be achieved depending on the alignment control capability of each film, and as a result, a polarizer layer having multiple regions with different absorption axis directions in the plane can be formed. Pattern alignment films can be formed using printing methods, mask rubbing for rubbing alignment films, and mask exposure for photoalignment films. When using a photoalignment film, the axis distribution may be drawn by irradiating it with different polarizations multiple times through a light-shielding mask with a pattern, or the axis distribution may be drawn by irradiating each region with different polarizations using a polarizing light source with a small exposure spot. Alternatively, a pattern alignment film can also be formed by uniformly forming an alignment film and separately printing an additive that affects the alignment control capability (e.g., the onium salt mentioned above) in a predetermined pattern. As the photoalignment film, a photoalignment film containing azobenzene dye or polyvinyl cinnamate is used.

[0053] The orientation step is a step in which the liquid crystal compounds contained in the coating film are oriented. The orientation step may include a drying process. The drying process can remove components such as solvents from the coating film. The drying process may be carried out by leaving the coating film at room temperature for a predetermined time (for example, natural drying), or by heating or blowing air.

[0054] The orientation step preferably includes a heat treatment. From the viewpoint of machinability, the heat treatment is preferably at 10 to 250°C, and more preferably at 25 to 190°C. The heating time is preferably at 1 to 300 seconds, and more preferably at 1 to 60 seconds.

[0055] The orientation step may include a cooling process performed after the heat treatment. The cooling process involves cooling the heated coating film to room temperature (approximately 20-25°C). This further fixes the orientation of the liquid crystal compounds contained in the coating film, resulting in a higher degree of orientation of the liquid crystal compounds. The cooling method is not particularly limited and can be carried out by known methods.

[0056] The process may include a step to harden the polarizer layer after the orientation step described above (hereinafter also referred to as the "hardening step"). The hardening step is carried out, for example, by heating or light irradiation (exposure). Among these, it is preferable that the hardening step be carried out by light irradiation. Various light sources can be used for hardening, such as infrared light, visible light, and ultraviolet light, but ultraviolet light is preferred. Furthermore, ultraviolet light may be irradiated while heating during hardening, or ultraviolet light may be irradiated through a filter that transmits only specific wavelengths. In addition, exposure may be carried out under a nitrogen atmosphere.

[0057] <Other Components> The first embodiment of the optical element of the present invention may include other components besides the first phase difference layer and polarizer layer described above.

[0058] (Support) The first embodiment of the optical element of the present invention may have a support. The type of support is not particularly limited, and known supports can be used. In particular, a transparent support is preferred. A transparent support refers to a support with a visible light transmittance of 60% or more, preferably 80% or more, and more preferably 90% or more.

[0059] Examples of supports include glass substrates and polymer films. Materials for the polymer film include cellulose polymers; acrylic polymers having acrylic acid ester polymers such as polymethyl methacrylate and lactone ring-containing polymers; thermoplastic norbornene polymers; polycarbonate polymers; polyester polymers such as polyethylene terephthalate and polyethylene naphthalate; styrene polymers such as polystyrene and acrylonitrile styrene copolymers; polyolefin polymers such as polyethylene, polypropylene, and ethylene-propylene copolymers; vinyl chloride polymers; amide polymers such as nylon and aromatic polyamides; imide polymers; sulfone polymers; polyethersulfone polymers; polyetheretherketone polymers; polyphenylene sulfide polymers; vinylidene chloride polymers; vinyl alcohol polymers; vinyl butyral polymers; arylate polymers; polyoxymethylene polymers; epoxy polymers; or polymers obtained by mixing these polymers. Furthermore, the support is preferably removable.

[0060] (Pattern alignment film) The first embodiment of the optical element of the present invention may have the pattern alignment film described above.

[0061] (Adhesive layer) The first embodiment of the optical element of the present invention may have an adhesive layer. The adhesive layer is preferably a transparent, optically isotropic adhesive similar to those used in ordinary image display devices, and is usually a pressure-sensitive adhesive.

[0062] (Adhesive Layer) The first embodiment of the optical element of the present invention may have an adhesive layer. The adhesive layer exhibits adhesive properties through drying and reaction after bonding. Polyvinyl alcohol-based adhesives (PVA-based adhesives) exhibit adhesive properties upon drying, enabling bonding of materials. Specific examples of curing adhesives that exhibit adhesive properties through reaction include active energy ray curing adhesives such as (meth)acrylate-based adhesives, and cationic polymerization curing adhesives.

[0063] Other components that the first embodiment of the optical element of the present invention may have, in addition to those mentioned above, include, for example, a protective layer, an oxygen barrier layer, an ultraviolet absorbing layer, and a blue light absorbing layer.

[0064] Although the first embodiment of the optical element of the present invention shown in Figures 5 and 6 above is planar, the present invention is not limited to this embodiment and may have a curved surface. Furthermore, the first embodiment of the optical element of the present invention may be bendable and may have a bent portion. Furthermore, the image display device observed through the first embodiment of the optical element of the present invention (corresponding to the image display device 100 in Figure 5) may also have a curved surface. Furthermore, the image display device may be bendable and may have a bent portion.

[0065] <<Second Embodiment>> Figure 7 shows a second embodiment of the optical element of the present invention. The optical element 10B shown in Figure 7 includes a first phase difference layer 12, a polarizer layer 14, and a second phase difference layer 20. In the optical element 10B shown in Figure 7, components similar to those in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted. The second phase difference layer 20 is located on the opposite side of the polarizer layer 14 from the first phase difference layer 12 side. The second phase difference layer 20 includes a third region 22 and a fourth region 24. Figure 8 is a view of the second phase difference layer 20 from the first phase difference layer 12 side. As shown in Figure 8, the third region 22 and the fourth region 24 are arranged in a stripe pattern, and the third region 22 and the fourth region 24 are arranged alternately. The arrows in the third region 22 and the fourth region 24 indicate the direction of the in-plane slow axis within each region. The third region 22 has an in-plane slow axis parallel to a direction rotated 45° clockwise with respect to the direction in which the third region 22 extends, and the fourth region 24 has an in-plane slow axis parallel to a direction rotated 45° counterclockwise with respect to the direction in which the fourth region 24 extends. In other words, the in-plane slow axis in the third region 22 and the in-plane slow axis in the fourth region 24 are orthogonal. The in-plane slow axis of the third region 22 and the in-plane slow axis of the fourth region 24 are both parallel to the main surface (the surface perpendicular to the thickness direction) of the second phase difference layer 20. Furthermore, when the optical element 10B is observed in the thickness direction, the third region 22 is positioned to overlap with the first region 16, and the fourth region 24 is positioned to overlap with the second region 18. In other words, the third region 22 is positioned to overlap with the first region 16 in the in-plane direction of the optical element 10B, and the fourth region 24 is positioned to overlap with the second region 18 in the in-plane direction of the optical element 10B.

[0066] As shown in Figure 7, the optical element 10B is applied when an observer OB observes the image display device 100 via a dimming device 30 incorporated in a near-eye display or the like. Near-eye displays such as AR (augmented reality) displays and VR (virtual reality) displays may incorporate a dimming device to block the view of the outside scenery. The dimming device 30 includes a first circular polarizer 32, a liquid crystal cell 34, and a second circular polarizer 36. In the dimming device 30, external light can be transmitted or blocked by electrically controlling the orientation direction of the liquid crystal compound in the liquid crystal cell 34. When an observer OB wearing a near-eye display equipped with such a dimming device 30 directly observes the image display device 100 that emits circularly polarized light, a blackout may occur. By providing the optical element 10B, the above problem is resolved, and color unevenness is also suppressed. More specifically, when circularly polarized light is incident on the optical element 10B, the light that passes through the first phase difference layer 12 and the polarizer layer 14 becomes linearly polarized light. In this case, as described above, the polarizer layer 14 has two regions (first region 16 and second region 18) with different absorption axis directions, so the light that passes through the polarizer layer 14 is linearly polarized light with two different vibration directions. As described above, the second phase difference layer 20 has a third region 22 corresponding to the position of the first region 16 in the in-plane direction, and a fourth region 24 corresponding to the position of the second region 18 in the in-plane direction. Linearly polarized light that passes through the first region 16 of the polarizer layer 14 is incident on the third region 22 and converted into circularly polarized light that passes through the first circular polarizer 32. Also, linearly polarized light that passes through the second region 18 of the polarizer layer 14 is incident on the fourth region 24 and converted into circularly polarized light that passes through the first circular polarizer 32. As a result, even when observer OB, wearing a near-eye display including the dimming device 30, observes the image display device 100, an image with suppressed color unevenness can be observed. The components constituting the optical element 10B will be described in detail below. The configurations of the first phase difference layer 12 and the polarizer layer 14 are as described above and will not be explained further.

[0067] <Second Phase Difference Layer> The second phase difference layer has a third region with an in-plane slow axis in the third direction, and a fourth region with an in-plane slow axis in the fourth direction, which is a different direction from the third direction. When observed from the thickness direction of the optical element (normal direction of the optical element), the third region is positioned to overlap with the first region, and the fourth region is positioned to overlap with the second region.

[0068] In Figures 7 and 8 described above, the in-plane slow axis in the third region 22 and the in-plane slow axis in the fourth region 24 are orthogonal, but the present invention is not limited to this embodiment. The direction of the in-plane slow axis in the third region and the direction of the in-plane slow axis in the fourth region do not need to be different from each other. The angle between the in-plane slow axis in the third region and the in-plane slow axis in the fourth region is preferably 90 ± 20° (70 to 110°), more preferably 90 ± 10° (80 to 100°), and even more preferably 90 ± 5° (85 to 95°) in terms of being able to further suppress color unevenness.

[0069] The relationship between the in-plane slow axis in the third region and the absorption axis in the first region is not particularly limited, but the angle between the in-plane slow axis in the third region and the absorption axis in the first region is preferably 45 ± 20° (25 to 65°) and more preferably 45 ± 10° (35 to 55°) in order to allow an observer wearing a near-eye display including a circular polarizer to observe the image display device more easily. When observed from the first phase difference layer side of the optical element, whether the in-plane slow axis in the third region is located at a position rotated clockwise or counterclockwise by an angle equal to the magnitude of the above-mentioned angle with respect to the absorption axis in the first region is appropriately adjusted depending on the type of circular polarizer included in the near-eye display.

[0070] The relationship between the in-plane slow axis in the fourth region and the absorption axis in the second region is not particularly limited, but the angle between the in-plane slow axis in the fourth region and the absorption axis in the second region is preferably 45 ± 20° (25 to 65°) and more preferably 45 ± 10° (35 to 55°) in order to allow an observer wearing a near-eye display including a circular polarizer to observe the image display device more easily. When observed from the first phase difference layer side of the optical element, whether the in-plane slow axis in the fourth region is located at a position rotated clockwise or counterclockwise by an angle equal to the magnitude of the above-mentioned angle with respect to the absorption axis in the second region is appropriately adjusted depending on the type of circular polarizer included in the near-eye display.

[0071] The shapes of the third and fourth regions are adjusted as appropriate to match the shapes of the first and second regions. For example, if both the first and second regions are striped, it is preferable that both the third and fourth regions are also striped. Furthermore, when the third and fourth regions are striped, it is preferable that their widths are the same as the widths of the striped first and second regions. Also, it is preferable that the area ratio of the third and fourth regions is the same as the area ratio of the first and second regions.

[0072] In the third region, the in-plane retardation at a wavelength of 550 nm is not particularly limited, but 120 to 180 nm is preferred, and 130 to 160 nm is more preferred, as it facilitates conversion to circularly polarized light. In the fourth region, the in-plane retardation at a wavelength of 550 nm is not particularly limited, but 120 to 180 nm is preferred, and 130 to 160 nm is more preferred, as it facilitates conversion to circularly polarized light.

[0073] The thickness of the second phase difference layer is not particularly limited, but from the viewpoint of thinning, it is preferably 10 μm or less, and more preferably 5 μm or less. The lower limit is not particularly limited, but it is often 0.1 μm or more.

[0074] The material constituting the second phase difference layer is not particularly limited, and examples include liquid crystal compounds. Examples of liquid crystal compounds used in the second phase difference layer include the compounds exemplified as liquid crystal compounds used in the polarizer layer. The liquid crystal compound may be fixed in the second phase difference layer. Furthermore, the liquid crystal compound in the second phase difference layer does not need to exhibit liquid crystalline properties anymore. For example, when the second phase difference layer is formed using a polymerizable liquid crystal compound, the liquid crystal compound may become highly molecular weight due to the curing reaction and may no longer exhibit liquid crystalline properties.

[0075] The liquid crystal compound is preferably an inverse wavelength-dispersive liquid crystal compound. An inverse wavelength-dispersive liquid crystal compound is a compound in which, when the in-plane retardation (Re) value in the visible light range of an optically anisotropic layer made by homogeneously oriented this compound is measured, the Re value increases as the measured wavelength increases.

[0076] (Method for manufacturing the second phase difference layer) The method for manufacturing the second phase difference layer is not particularly limited, and known methods can be used. For example, a method comprising the steps of applying a composition for forming the second phase difference layer containing a liquid crystal compound onto a pattern alignment film to form a coating film (hereinafter also referred to as the "coating film formation step") and aligning the liquid crystal compound contained in the coating film (hereinafter also referred to as the "alignment step") in this order is preferred. Each step will be described below.

[0077] The coating film formation step involves applying a second phase difference layer forming composition onto a pattern alignment film to form a coating film. The second phase difference layer forming composition contains a liquid crystal compound. As mentioned above, the liquid crystal compound may be a polymerizable liquid crystal compound. The second phase difference layer forming composition may also contain components other than the liquid crystal compound (e.g., solvent, polymerization initiator, etc.).

[0078] Known methods for applying the composition for forming the second phase difference layer include roll coating, gravure printing, spin coating, wire bar coating, extrusion coating, direct gravure coating, reverse gravure coating, die coating, spray coating, and inkjet coating.

[0079] Pattern alignment films are films that have different alignment control capabilities. Therefore, when liquid crystal compounds are aligned on a pattern alignment film, different alignment states can be achieved depending on the alignment control capability of each film, and as a result, a second phase difference layer can be formed that has multiple regions with different directions of in-plane slow axis within the plane. Pattern alignment films can be formed using printing methods, mask rubbing for rubbing alignment films, and mask exposure for photoalignment films. When using a photoalignment film, the axis distribution may be drawn by irradiating it with different polarizations multiple times through a light-shielding mask with a pattern, or the axis distribution may be drawn by irradiating each region with different polarizations using a polarizing light source with a small exposure spot. Alternatively, a pattern alignment film can also be formed by uniformly forming an alignment film and separately printing an additive that affects the alignment control capability (e.g., the onium salt mentioned above) in a predetermined pattern. As the photoalignment film, a photoalignment film containing an azobenzene dye or polyvinyl cinnamate is used.

[0080] The orientation step is a step in which the liquid crystal compounds contained in the coating film are oriented. The orientation step may include a drying process. The drying process can remove components such as solvents from the coating film. The drying process may be carried out by leaving the coating film at room temperature for a predetermined time (for example, natural drying), or by heating or blowing air.

[0081] The orientation step preferably includes a heat treatment. From the viewpoint of machinability, the heat treatment is preferably 10 to 250°C, and more preferably 25 to 190°C. The heating time is preferably 1 to 300 seconds, and more preferably 1 to 60 seconds. The orientation step may also include a cooling treatment performed after the heat treatment.

[0082] The process may include a step to harden the polarizer layer after the orientation step described above (hereinafter also referred to as the "hardening step"). The hardening step is carried out, for example, by heating or light irradiation (exposure). Among these, it is preferable that the hardening step be carried out by light irradiation. Various light sources can be used for hardening, such as infrared light, visible light, and ultraviolet light, but ultraviolet light is preferred. Furthermore, ultraviolet light may be irradiated while heating during hardening, or ultraviolet light may be irradiated through a filter that transmits only specific wavelengths. In addition, exposure may be carried out under a nitrogen atmosphere.

[0083] <Other Components> The second embodiment of the optical element of the present invention may include other components other than the first phase difference layer, polarizer layer, and second phase difference layer described above. Examples of other components include those listed in the first embodiment.

[0084] Although the second embodiment of the optical element of the present invention shown in Figures 7 and 8 above is planar, the present invention is not limited to this embodiment and may have a curved surface. Furthermore, the second embodiment of the optical element of the present invention may be bendable and may have a bent portion. Furthermore, the image display device observed through the second embodiment of the optical element of the present invention (corresponding to the image display device 100 in Figure 7) may also have a curved surface. Furthermore, the image display device may be bendable and may have a bent portion.

[0085] As described above, the second embodiment of the optical element is preferably used when an observer is wearing a near-eye display such as an AR (augmented reality) display or a VR (virtual reality) display.

[0086] The present invention will be specifically described below based on examples. The materials, reagents, amounts and proportions of substances, and procedures shown in the following examples can be modified as appropriate, as long as they do not depart from the spirit of the present invention. Therefore, the present invention is not limited to the following examples.

[0087] <Preparation of the first phase difference films A1 and A2> (First phase difference layer used in the comparative example and example) A polyethylene terephthalate (PET) film with a thickness of 100 μm was prepared by the following method.

[0088] —Synthesis of raw material polyester— —Raw material polyester 1— As shown below, raw material polyester 1 (Sb catalyst-based PET) was obtained by a continuous polymerization apparatus using a direct esterification method in which terephthalic acid and ethylene glycol were directly reacted to remove water by distillation, followed by polycondensation under reduced pressure.

[0089] (1) Esterification reaction In the first esterification reactor, 4.7 tons of high-purity terephthalic acid and 1.8 tons of ethylene glycol were mixed over 90 minutes to form a slurry, which was continuously supplied to the first esterification reactor at a flow rate of 3800 kg / h. Next, an ethylene glycol solution of antimony trioxide was continuously supplied to the first esterification reactor, and the reaction was carried out at a reactor temperature of 250°C, under stirring, with an average residence time of approximately 4.3 hours. At this time, antimony trioxide was continuously added so that the amount of Sb added was 150 ppm by mass in terms of elemental value.

[0090] The reactants were transferred to a second esterification reactor and reacted under stirring at a reactor temperature of 250°C for an average residence time of 1.2 hours. Ethylene glycol solutions of magnesium acetate and ethylene glycol solutions of trimethyl phosphate were continuously supplied to the second esterification reactor so that the amounts of Mg and P added were 65 ppm by mass and 35 ppm by mass, respectively, on an elemental basis.

[0091] (2) Polycondensation reaction The esterification reaction product obtained above is continuously supplied to the first polycondensation reaction vessel and stirred, at a reaction temperature of 270°C and a reaction vessel pressure of 20 torr (2.67 × 10⁻¹⁰). －３ Polycondensation was performed at MPa with an average residence time of approximately 1.8 hours.

[0092] Next, the obtained reactants are transferred to a second double condensation reactor, where they are stirred, with a reactor temperature of 276°C and a reactor pressure of 5 torr (6.67 × 10⁻⁶). －４ The reaction (polycondensation) was carried out under conditions of MPa with a residence time of approximately 1.2 hours.

[0093] Next, the resulting reactants are transferred to a third double condensation reactor, where the reactor temperature is 278°C and the reactor pressure is 1.5 torr (2.0 × 10⁻⁶). －４ The reaction (polycondensation) was carried out under conditions of MPa with a residence time of 1.5 hours to obtain the reactant (polyethylene terephthalate (PET)).

[0094] Next, the resulting reaction product was extruded in strand form into cold water and immediately cut to produce polyester pellets (cross-section: major diameter approximately 4 mm, minor diameter approximately 2 mm, length: approximately 3 mm). The obtained polymer had an intrinsic viscosity IV = 0.63 dL / g. This polymer was designated as raw material polyester 1. The intrinsic viscosity IV was determined by dissolving raw material polyester 1 in a 1,1,2,2-tetrachloroethane / phenol (= 2 / 3 [mass ratio]) mixed solvent and measuring the viscosity of the solution in this mixed solvent at 25°C.

[0095] --Raw material polyester 2-- Using a kneading extruder, 10 parts by mass of dried ultraviolet absorber (2,2'-(1,4-phenylene)bis(4H-3,1-benzoxazinon-4-one)) and 90 parts by mass of raw material polyester 1 (IV = 0.63 dL / g) were mixed to obtain raw material polyester 2 containing the ultraviolet absorber.

[0096] ―Film Forming Process― Raw material polyester 1 (90 parts by mass) and raw material polyester 2 (10 parts by mass) containing an ultraviolet absorber were dried to a moisture content of 20 ppm by mass or less, and then placed into the hopper 1 of a 50 mm diameter single-screw kneading extruder 1, and melted at 300°C in the extruder 1. The molten resin was extruded from the die through a gear pump and a filter (pore size 20 μm) under the following extrusion conditions. The extrusion conditions for the molten resin were set to a pressure fluctuation of 1% and a temperature distribution of molten resin of 2%, and the molten resin was extruded from the die. Specifically, the back pressure was increased by 1% relative to the average pressure inside the extruder barrel, and the extruder piping temperature was heated to a temperature 2% higher than the average temperature inside the extruder barrel. The molten resin extruded from the die was extruded onto a cooling cast drum set to a temperature of 25°C, and adhered to the cooling cast drum using an electrostatic application method. The film was peeled off using a peeling roll positioned opposite the cooling cast drum to obtain an unstretched polyester film 1.

[0097] —Transverse stretching process— —Preheating section— The preheating temperature was set to 90°C, and the unstretched polyester film 1 was heated to a temperature at which it could be stretched.

[0098] --Stretching Section-- A preheated, unstretched polyester film 1 was guided into a tenter (transverse stretcher), and while holding the ends of the film with clips, it was transversely stretched in the TD direction (film width direction, transverse direction) under the following conditions and by the following method and conditions to obtain a transversely stretched polyester film 1. <Conditions> ・Transverse stretching temperature: 90°C ・Transverse stretching ratio: 4.3 times

[0099] --Thermal Fixation Section-- Next, a thermal fixation process was performed while controlling the surface temperature of the transversely stretched polyester film 1 to the following temperature: <Conditions> ・Thermal fixation temperature: 180°C ・Thermal fixation time: 15 seconds

[0100] --Thermal Relaxation Section-- The heat-set transversely stretched polyester film 1 was heated to the following temperature to relax the film. • Thermal relaxation temperature: 170°C • Thermal relaxation rate: 2% in the TD direction (film width direction, transverse direction)

[0101] --Cooling Section-- Next, the transversely stretched polyester film 1, after heat relaxation, was cooled at a cooling temperature of 50°C.

[0102] The in-plane retardation of the first phase difference film A1 obtained in this way was measured with Axoscan, and the in-plane retardation Re(550) = 10000 nm at a wavelength of 550 nm was found to be 10000 nm.

[0103] The first phase difference film A2 was fabricated in the same manner as the first phase difference film A1, except that the transverse stretching ratio was adjusted so that the in-plane retardation Re(550) = 3000 nm at a wavelength of 550 nm.

[0104] <Preparation of Polarizer Layer-Containing Laminate 1> (Preparation of Substrate 1) The following composition was placed in a mixing tank, stirred, and heated at 90°C for 10 minutes. The resulting composition was then filtered through filter paper with an average pore size of 34 μm and a sintered metal filter with an average pore size of 10 μm to prepare a dope. The solid content concentration of the dope was 23.5% by mass, the amount of plasticizer added was a ratio to the cellulose acylate, and the solvent of the dope was methylene chloride / methanol / butanol = 81 / 18 / 1 (mass ratio).

[0105] -------------------------------------------------- Cellulose acylate dope -------------------------------------------------- Cellulose acylate (acetyl substitution degree 2.86, viscosity-average degree of polymerization 310) 100 parts by mass Sugar ester compound 1 (formula (S4) below) 6.0 parts by mass Sugar ester compound 2 (formula (S5) below) 2.0 parts by mass Silica particle dispersion (AEROSIL R972, manufactured by Nippon Aerosil Co., Ltd.) 0.1 parts by mass Solvent (methylene chloride / methanol / butanol) 351.9 parts by mass

[0106] Sugar ester compound 1

[0107]

[0108] Sugar ester compound 2

[0109]

[0110] The dope prepared as described above was cast using a drum film-forming machine. The dope was cast from the die so that it was in contact with a metal support cooled to 0°C, and then the resulting web (film) was peeled off the drum. The drum was made of SUS (stainless steel).

[0111] After the casting process, the obtained web (film) was peeled from the drum and dried for 20 minutes in a tenter device at 30-40°C during film transport, using a tenter device that clipped both ends of the web with clips during transport. Subsequently, the web was further dried by zone heating while being transported on a roll. The obtained web was knurled and then wound up to form the base material 1. The thickness of the obtained base material 1 was 60 μm, the in-plane retardation Re(550) at a wavelength of 550 nm was 1 nm, and the thickness-direction retardation Rth(550) at a wavelength of 550 nm was 35 nm.

[0112] (Preparation of photo-alignment film A1) The photo-alignment film-forming composition A1, described later, was continuously applied to the substrate 1 using a wire bar. The support on which the coating film was formed was dried for 120 seconds with hot air at 140°C and a wind speed of 1 m / s, and then polarized ultraviolet light (10 mJ / cm²) was irradiated onto the coating film. ２ A photo-alignment film A1 was obtained by using an ultra-high pressure mercury lamp. The thickness of the photo-alignment film A1 was 1.5 μm. The solid content concentration of the photo-alignment film forming composition A1 was 20%, and the viscosity was 3.5 mPa·s.

[0113] -------------------------------------------------- Composition of Photo-Alignment Film Forming Composition A1 -------------------------------------------------- ・The following polymer PA-1 (photo-alignment compound) 100.00 parts by mass ・EPICLON N-695 (manufactured by DIC Corporation) 55.74 parts by mass ・jER YX7400 (manufactured by Mitsubishi Chemical Corporation) 18.75 parts by mass ・The following polymer compound PB-1 8.01 parts by mass ・The following thermal cationic polymerization initiator PAG-1 16.75 parts by mass ・The following stabilizer DIPEA 1.06 parts by mass ・Butyl acetate 803 parts by mass --------------------------------------------------

[0114] Polymer PA-1 (photo-oriented compound) (Weight-average molecular weight: 32,000; in the formula below, the values ​​listed for each repeating unit represent the content (mass%) of each repeating unit relative to the total number of repeating units.)

[0115]

[0116] Polymer compound PB-1 (weight-average molecular weight: 18,000; in the formula below, the numerical values ​​listed for each repeating unit represent the content (mass%) of each repeating unit relative to the total number of repeating units.)

[0117]

[0118] Thermal cationic polymerization initiator PAG-1

[0119]

[0120] Stabilizer DIPEA

[0121]

[0122] (Formation of Polarizer Layer 1) A polarizer layer-forming composition 1 with the following composition was continuously applied to the obtained photo-alignment film A1 using a wire bar to form a coating film. Next, the coating film was heated at 140°C for 15 seconds, then at 80°C for 5 seconds, and the coating film was cooled to room temperature (23°C). Next, the coating film was heated at 75°C for 60 seconds and cooled again to room temperature. After that, a polarizer layer 1 (thickness: 1.8 μm) was formed on the photo-alignment film A1 by irradiation with an LED (light-emitting diode) lamp (center wavelength 365 nm) at an irradiation condition of 300 mJ. The total content of the first dichroic substance Dye-C1, the second dichroic substance Dye-M1, and the third dichroic substance Dye-Y1 contained in the polarizer layer 1 was 220 mg / cm². ３ The transmittance of the polarizer layer 1 was measured using a spectrophotometer in the wavelength range of 280 to 780 nm, and the average visible light transmittance was 43%. Here, the average visible light transmittance refers to the arithmetic mean of the transmittance in 5 nm increments in the visible light region (wavelength 400 to 700 nm). A spectrophotometer (for example, a multi-channel spectrometer (manufactured by OCEAN OPTICS, product name "QE65000")) was used to measure the transmittance. The absorption axis of the polarizer layer 1 was in the plane of the polarizer layer 1 and at 90° with respect to the width direction of the substrate 1.

[0123] -------------------------------------------------- Composition of Polarizer Layer Forming Composition 1 -------------------------------------------------- ・First dichroic substance Dye-C1 below 0.65 parts by mass ・Second dichroic substance Dye-M1 below 0.15 parts by mass ・Third dichroic substance Dye-Y1 below 0.52 parts by mass ・Liquid crystal compound L-1 below 2.69 parts by mass ・Liquid crystal compound L-2 below 1.15 parts by mass ・Adhesion improver A-1 below 0.17 parts by mass ・Polymerization initiator IRGACUREOXE-02 (manufactured by BASF) 0.17 parts by mass ・Surfactant F-1 below 0.013 parts by mass ・Cyclopentanone 92.14 parts by mass ・Benzyl alcohol 2.36 parts by mass --------------------------------------------------

[0124] Dichroic substance Dye-C1

[0125]

[0126] Dichroic substance Dye-M1

[0127]

[0128] Dichroic substance Dye-Y1

[0129]

[0130] Liquid crystal compound L-1 (weight-average molecular weight: 18,000; in the formula below, the values ​​listed for each repeating unit ("59", "15", "26") represent the content (mass %) of each repeating unit relative to the total number of repeating units.)

[0131]

[0132] Liquid crystal compound L-2 (a mixture of the following liquid crystal compounds (RA), (RB), and (RC) in a mass ratio of 84:14:2)

[0133]

[0134] Adhesion improver A-1

[0135]

[0136] Surfactant F-1 (Weight-average molecular weight: 15,000; in the formula, the numerical value indicated for each repeating unit represents the content (mass%) of each repeating unit relative to the total number of repeating units.)

[0137]

[0138] (Formation of Oxygen Barrier Layer 1) The oxygen barrier layer-forming composition 1, having the following composition, was continuously applied to the polarizer layer 1 using a wire bar. Then, by drying with hot air at 80°C for 5 minutes, a laminate was obtained in which an oxygen barrier layer 1 made of polyvinyl alcohol (PVA) with a thickness of 1.0 μm was formed, i.e., a polarizer layer-containing laminate 1 (hereinafter simply referred to as "laminated body 1") comprising the substrate 1, photo-alignment film A1, polarizer layer 1, and oxygen barrier layer 1 adjacent to each other in this order. ------------------------------------------------------------------- Composition of Oxygen Barrier Layer-Forming Composition 1 ------------------------------------------------------------------- ・Modified polyvinyl alcohol 3.80 parts by mass ・Initiator Irg2959 0.20 parts by mass ・Water 70 parts by mass ・Methanol 30 parts by mass -------------------------------------------------------------------

[0139] Modified polyvinyl alcohol (In the formula, the numerical values ​​listed for each repeating unit represent the content (mass %) of each repeat relative to the total number of repeating units.)

[0140]

[0141] <Preparation of polarizer layer-containing laminates 2-10> (Preparation of photo-alignment film A2) The aforementioned photo-alignment film-forming composition A1 was continuously applied to the aforementioned substrate 1 using a wire bar. The support on which the coating film was formed was dried for 120 seconds with hot air at 140°C and a wind speed of 1 m / s, and then polarized ultraviolet light (10 mJ / cm²) was irradiated onto the coating film. ２A provisional photo-alignment film A2 was formed by irradiating it with ultra-high pressure mercury lamp. Next, a striped mask with a period of 1 mm was prepared, and the mask was placed on top of the provisional photo-alignment film A2, followed by a second irradiation with polarized ultraviolet light (10 mJ / cm²). ２ Photo-alignment film A2 was obtained by performing (using an ultra-high pressure mercury lamp). The thickness of photo-alignment film A2 was 1.5 μm. The polarization direction of the second polarization exposure was set so that the angle with the polarization direction of the first polarization exposure was 90°. A striped mask was used in which the transmittance to ultraviolet light was less than 1% in the first region and 80% or more in the second region, and the first and second regions were arranged alternately with the same width. Finally, a polarizer layer will be laminated on the photo-alignment film to create a polarizer layer-containing laminate, and the photo-alignment film was prepared so that the absorption axis of the first region was 90° with respect to the direction of extension of the stripes, and the absorption axis of the second region was 0° with respect to the direction of extension of the stripes.

[0142] (Fabrication of photo-alignment films A3-6) Photo-alignment films A3-6 were obtained in the same manner as photo-alignment film A2, except that the period of the striped mask was 0.05 mm, 0.1 mm, 2 mm, or 2.5 mm.

[0143] (Preparation of polarizer layer-containing laminates 2 to 10) Polarizer layer-containing laminates 2 to 10 were prepared in the same manner as polarizer layer-containing laminate 1, except that photo-alignment films A2 to 6 were used as photo-alignment films, and the amount of polarizer layer-forming composition 1 applied was adjusted so that the average visible light transmittance of the polarizer layer was 39%, 40%, 50%, or 51%.

[0144] Table 1 shows the configurations of each polarizer layer-containing laminates 2 to 10. In Table 1, the "Laminated body X" column represents the polarizer layer-containing laminated body X. For example, "Laminated body 2" in Table 1 represents polarizer layer-containing laminated body 2, and "Laminated body 3" represents polarizer layer-containing laminated body 3. In Table 1, the "Type of photo-alignment film" column represents the type of the photo-alignment film used, wherein "A2" represents photo-alignment film A2, "A3" represents photo-alignment film A3, "A4" photo-alignment film A4, "A5" represents photo-alignment film A5, and "A6" represents photo-alignment film A6. In Table 1, the "Stripe width (mm)" column represents the width (mm) of the striped first region and second region. In Table 1, the "Average visible light transmittance (%)" column represents the average visible light transmittance (%) of the polarizer layer.

[0145]

[0146] <Preparation of Second Retardation Film B1> A PET film having a thickness of 100 μm (manufactured by Toyobo Co., Ltd., Cosmo Shine A4265) was prepared as a support. This PET film has an easy-adhesion layer on one surface. The following composition B1 for forming a photo-alignment film was applied onto this support with a wire bar, and then dried with hot air at 120° C. for 60 seconds. Thereafter, in a low-oxygen atmosphere (100 volume ppm or less), at 70° C., the illuminance was 100 mW / cm ２ , and the film was cured by irradiating linearly polarized ultraviolet rays having an irradiation dose of 100 mJ / cm ２ . This ultraviolet ray was obtained by transmitting through a long-pass filter having a transmission band at a wavelength of 340 nm or more. Next, the cured coating film had an illuminance of 7 mW / cm ２ , and a provisional photo-alignment film B1 was formed by irradiating linearly polarized ultraviolet rays (wavelength: 313 nm) with an irradiation dose of 7.9 mJ / cm ２ from the photo-alignment film side. The linearly polarized ultraviolet ray with a wavelength of 313 nm was obtained by transmitting ultraviolet rays emitted from a mercury lamp through a band-pass filter having a transmission band at a wavelength of 313 nm and a wire grid polarizer. Next, a striped mask with a period of 1 mm was prepared, and after superimposing the mask on the provisional photo-alignment film B1, the illuminance was 7 mW / cm ２ , with an irradiation dose of 7.9 mJ / cm ２A second polarization exposure was performed by irradiating the alignment film side with linearly polarized ultraviolet light (wavelength 313 nm). In this second polarization exposure, the polarization direction was set so that the angle with the polarization direction of the first polarization exposure was 90°. A striped mask was used in which the transmittance to ultraviolet light was less than 1% in the third region and 80% or more in the fourth region, and the third and fourth regions were arranged alternately with the same width. This resulted in a photo-alignment film B1 in which the orientation direction changed by 90° with a period of 1 mm. Finally, a second phase difference film was fabricated by laminating the phase difference layer composition 1 on top of the photo-alignment film. The photo-alignment film was prepared so that the in-plane slow axis of the third region was 45° clockwise with respect to the extension direction of the stripes when viewed from the phase difference layer side, and the in-plane slow axis of the fourth region was 45° counterclockwise with respect to the extension direction of the stripes when viewed from the phase difference layer side.

[0147] (Composition B1 for photo-alignment film formation) The components listed below were stirred in a container at room temperature to prepare composition B1 for photo-alignment film formation.

[0148] ------------------------------------------------------------------- Composition of Composition B1 for Photo-Alignment Film Formation ------------------------------------------------------------------- ・100.00 parts by mass of the polymer M-PA-1 below ・5.00 parts by mass of the photopolymerization initiator A below ・2625.00 parts by mass of n-butyl acetate -------------------------------------------------------------------

[0149] Polymer M-PA-1 (In the formula, the numerical values ​​listed for each repeating unit represent the content (mass %) of each repeating unit relative to the total number of repeating units.)

[0150]

[0151] Photopolymerization initiator A

[0152]

[0153] A phase difference layer composition 1 having the composition described below was applied onto the photo-alignment film B1 using a bar coater. The coating formed on the photo-alignment film B1 was heated to 120°C with hot air, then cooled to 60°C, and then heated at a wavelength of 365 nm and a pressure of 100 mJ / cm² using a high-pressure mercury lamp under a nitrogen atmosphere. ２ The coating is irradiated with ultraviolet light, followed by heating to 120°C while applying 500 mJ / cm² of UV light. ２ By irradiating the coating film with ultraviolet light, the orientation of the liquid crystalline compound was fixed, and a second phase difference film B1 was fabricated. The thickness of the second phase difference layer formed with phase difference layer composition 1 was 2.7 μm, and Re(550) was 155 nm.

[0154] ------------------------------------------------------------------- Phase difference layer composition 1 -------------------

[0155] Polymerizable liquid crystalline compound LA-1 (tBu represents a tert-butyl group)

[0156]

[0157] Polymerizable liquid crystal compound LA-2

[0158]

[0159] Polymerizable liquid crystal compound LA-3

[0160]

[0161] Polymerizable liquid crystalline compound LA-4 (Me represents a methyl group)

[0162]

[0163] Polymerization initiator PI-1

[0164]

[0165] Leveling agent T-1

[0166]

[0167] <Preparation of Second Phase Difference Films B2-5> Second phase difference films B2-5 were obtained in the same manner as second phase difference film B1, except that the period of the striped mask was 0.05 mm, 0.1 mm, 2.0 mm, or 2.5 mm.

[0168] <Preparation of Optical Elements of Comparative Example 1, Examples 1 and 2> According to the configurations shown in Table 2, a first phase difference film (one of the first phase difference films A1 and A2) was bonded to glass via an adhesive, and then the oxygen barrier layer 1 of a polarizer layer-containing laminate (one of the polarizer layer-containing laminates 1 and 2) was bonded to the first phase difference film via an adhesive. The substrate 1 was then peeled off and removed from the resulting bonded body to obtain the optical elements of Comparative Example 1, Examples 1 and 2.

[0169] <Evaluation 1> For the optical elements of Comparative Example 1, Examples 1 and 2, with the polarizer layer-containing laminate positioned towards the eye, a solid white image and a black square mark with a diameter of 1 cm in the center of the solid white image were displayed on an Apple iPad Pro (2021 model, 11-inch, using an LCD display) and observed. Brightness, color unevenness, image blur, and pattern visibility were visually evaluated according to the criteria described below. The results are shown in Table 2.

[0170] The evaluation was conducted according to the following criteria: (Brightness) A: The solid white image appears sufficiently bright. B: The solid white image appears slightly dark. C: The solid white image appears slightly dark but within acceptable limits. D: The solid white image appears one level darker. (Color unevenness) A: There is no color unevenness in the solid white image. B: There is slight variation in color in the solid white image. C: There is variation in color in the solid white image but within acceptable limits. D: Color unevenness is clearly visible in the solid white image. (Image blur) A: The black square mark is clearly visible. B: The edges of the black square mark appear slightly blurred. C: The black square mark appears slightly blurred but within acceptable limits. D: The black square mark appears as a multiple image. (Pattern visibility) A: The stripes do not appear in the field of view when viewing the solid white image. B: The stripes are slightly visible in the field of view when viewing the solid white image. C: A slight stripe is visible in the field of view when viewing a solid white image, but it is within acceptable limits. D: The stripe is clearly visible in the field of view when viewing a solid white image.

[0171] In Table 2, the "First Phase Difference Film" column indicates the type of phase difference film used, where "A1" represents the first phase difference film A1 and "A2" represents the second phase difference film A2. In Table 2, the "Laminate" column indicates the type of polarizer layer-containing laminate used, where "1" represents polarizer layer-containing laminate 1 and "2" represents polarizer layer-containing laminate 2. For example, the optical element of Example 1 is formed using the first phase difference film A1 and polarizer layer-containing laminate 2.

[0172]

[0173] As shown in Table 2 above, it was confirmed that the optical element of the present invention exhibits the desired effect. In particular, a comparison between Examples 1 and 2 confirmed that when the in-plane retardation of the first phase difference layer at a wavelength of 550 nm is 5000 nm or greater, color unevenness is further suppressed.

[0174] <Fabrication of Optical Elements in Comparative Example 2 and Examples 3-11> The optical element of Comparative Example 2 was obtained by laminating the first phase difference film A1 to glass via an adhesive, according to the configuration shown in Table 3. The optical elements of Examples 3-11 were obtained by laminating the first phase difference film A1 to glass via an adhesive, following the configuration shown in Table 3, then laminating a polarizer layer-containing laminate (any of polarizer layer-containing laminates 2-10) to the first phase difference film A1 via an adhesive, peeling off and removing the substrate 1, and then laminating a second phase difference film (any of second phase difference films B1-B5) to the exposed photo-alignment film via an adhesive, and peeling off and removing the PET support. In this case, the lamination of the polarizer layer-containing laminate and the second phase difference film was carried out so that the first region overlapped with the third region and the second region overlapped with the fourth region, and the final polarization state of the light entering from the glass side of the optical elements of Examples 3-11 was adjusted to be right-circular polarization. Furthermore, when the optical element was observed along the thickness direction (normal direction of the optical element), the third region of the second phase difference layer in the second phase difference film was arranged to overlap with the first region of the polarizer layer, and the fourth region of the second phase difference layer in the second phase difference film was arranged to overlap with the second region of the polarizer layer.

[0175] <Evaluation 2> A near-eye display was fabricated by bonding the optical elements of Comparative Example 2 and Examples 3-11 to the opposite side of the XREAL Air2 Pro AR glasses manufactured by XREAL, with the glass facing outwards. It was confirmed that these AR glasses have the properties of a circular polarizer, cutting the left circularly polarized component of ambient light and transmitting the right circularly polarized component. A solid white image and a black square mark with a diameter of 1 cm in the center of the solid white image were displayed on an Apple iPad Pro (2021 model, 11-inch, using an LCD display) and observed through this near-eye display. Visual evaluations of brightness, color unevenness, image blur, and pattern visibility were performed using the same criteria as in <Evaluation 1> above. The results are shown in Table 3.

[0176] In Table 3, the "First Phase Difference Film" column indicates the type of phase difference film used, with "A1" representing the first phase difference film A1. In Table 3, the "Laminate" column indicates the type of laminate used, with "2" representing laminate 2, "3" representing laminate 3, "4" representing laminate 4, "5" representing laminate 5, "6" representing laminate 6, "7" representing laminate 7, "8" representing laminate 8, "9" representing laminate 9, and "10" representing laminate 10. In Table 3, the "Second Phase Difference Film" column indicates the type of phase difference film used, with "B1" representing the second phase difference film B1, "B2" representing the second phase difference film B2, "B3" representing the second phase difference film B3, "B4" representing the second phase difference film B4, and "B5" representing the second phase difference film B5. For example, the optical element of Example 3 is formed using a first phase difference film A1, a polarizer layer-containing laminate 2, and a second phase difference film B1. The "stripe width (mm)" in Table 3 represents the "stripe width (mm)" in Table 1. The "average visible light transmittance (%)" in Table 3 represents the "average visible light transmittance (%)" in Table 1.

[0177]

[0178] As shown in Table 3, the optical element of the present invention was confirmed to exhibit the desired effects. In particular, a comparison of Examples 3 to 7 confirmed that when the average visible light transmittance of the polarizer layer was 40% or higher, the brightness was superior, and when it was 42% or higher, the brightness was even superior. Furthermore, a comparison of Examples 3 to 7 confirmed that when the average visible light transmittance of the polarizer layer was 50% or lower, color unevenness was suppressed more effectively, and when it was 48% or lower, color unevenness was further suppressed. Furthermore, a comparison of Examples 8 to 11 confirmed that when the stripe width was 0.1 mm or higher, image blur was suppressed more effectively, and when it was 0.5 mm or higher, image blur was further suppressed. Furthermore, a comparison of Examples 8 to 11 confirmed that when the stripe width was 2.0 mm or lower, the pattern visibility was superior, and when it was 1.5 mm or lower, the pattern visibility was even superior.

[0179] 10A, 10B Optical elements 12 First phase difference layer 14 Polarizer layer 16 First region 18 Second region 20 Second phase difference layer 22 Third region 24 Fourth region 30 Dimming device 32 First circular polarizer 34 Liquid crystal cell 36 Second circular polarizer 100 Image display device

Claims

1. An optical element comprising a first phase difference layer and a polarizer layer, wherein the in-plane retardation of the first phase difference layer at a wavelength of 550 nm is 3000 nm or more, and the polarizer layer has a plurality of regions with different absorption axis directions in its plane.

2. The optical element according to claim 1, wherein the polarizer layer comprises a liquid crystal compound and a dichroic substance.

3. The optical element according to claim 1, wherein the average visible light transmittance of the polarizer layer is in the range of 40 to 50%.

4. The optical element according to claim 1, wherein the polarizer layer has a first region having an absorption axis in a first direction and a second region having an absorption axis in a second direction different from the first direction.

5. The optical element according to claim 4, wherein the first direction and the second direction are orthogonal.

6. The optical element according to claim 4, wherein the ratio of the area of ​​the second region to the area of ​​the first region is 4 / 6 to 6 / 4.

7. The optical element according to claim 4, wherein the first region and the second region are arranged alternately in a stripe pattern.

8. The optical element according to claim 7, wherein the widths of the first region and the second region are 0.1 to 2.0 mm.

9. The optical element according to claim 4, further comprising a second phase difference layer on the side of the polarizer layer opposite to the first phase difference layer, wherein the second phase difference layer has a third region having an in-plane slow axis in a third direction and a fourth region having an in-plane slow axis in a fourth direction different from the third direction, wherein when the optical element is observed in the thickness direction, the third region is positioned to overlap with the first region and the fourth region is positioned to overlap with the second region.

10. A near-eye display having the optical element described in any one of claims 1 to 9.

Images