Display system and display body

Abstract

To provide a display system that may reduce the weight and increase the definition of VR goggles.SOLUTION: A display system comprises: a display element that emits image light via a polarization member; a reflection portion that includes a reflection type polarization member and reflects the image light in front of the display element; a first lens portion that is disposed between the display element and the reflection portion; a half mirror that transmits the image light between the display element and the first lens portion and reflects the light from the reflection portion toward the reflection portion; first and second phase difference members and first and second members that are arranged between the display element and the half mirror. The first and second phase difference members are each capable of converting linearly polarized light into circularly polarized light or converting circularly polarized light into linearly polarized light. The first and second members each give a phase difference in a thickness direction and include a positive C plate, and are located in front of or behind the phase difference member between the display element and the half mirror and between the half mirror and the reflection portion. The first and second members further each include a negative C plate.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a display system and a display. [Background technology]

[0002] Image display devices, such as liquid crystal display devices and electroluminescence (EL) display devices (e.g., organic EL display devices), are rapidly becoming popular. In image display devices, optical components such as polarizing components and phase difference components are generally used to realize image display and improve the performance of the image display (see, for example, Patent Document 1).

[0003] In recent years, new applications for image display devices have been developed. For example, goggles with displays (VR goggles) for realizing virtual reality (VR) have begun to be commercialized. As VR goggles are being considered for use in a variety of situations, there is a demand for them to be lightweight and have high definition. Lightweightness can be achieved, for example, by thinning the lenses used in VR goggles. Meanwhile, there is also a demand for the development of optical components suitable for display systems using thin lenses. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2021-103286 Summary of the Invention [Problem to be solved by the invention]

[0005] In view of the above, a main object of the present invention is to provide a display system that can realize lightweight and high-definition VR goggles. [Means for solving the problem]

[0006] 1. A display system according to an embodiment of the present invention is a display system that displays an image to a user, comprising: a display element having a display surface that emits light representing an image forward via a polarizing member; a reflecting section that is arranged in front of the display element and includes a reflective polarizing member and reflects the light emitted from the display element; a first lens section that is arranged on an optical path between the display element and the reflecting section; a half mirror that is arranged between the display element and the first lens section and transmits the light emitted from the display element and reflects the light reflected by the reflecting section toward the reflecting section; a first phase difference member that is arranged on the optical path between the display element and the half mirror; The optical path between the half mirror and the reflecting section includes a second phase difference member, and a second member, which is arranged on the optical path between the half mirror and the reflecting section. The first phase difference member and the second phase difference member are each phase difference members that can convert linearly polarized light into circularly polarized light or circularly polarized light into linearly polarized light. The first member and the second member are each members that impart a phase difference in the thickness direction and include a positive C plate. Both between the display element and the half mirror and between the half mirror and the reflecting section, the member that imparts the phase difference in the thickness direction is located in front of or behind the phase difference member. The first member or the second member further includes a negative C plate. 2. In the display system described in 1 above, the member that provides the thickness direction phase difference may be located in front of the phase difference member both between the display element and the half mirror and between the half mirror and the reflecting section, and the second member may include a negative C plate. 3. In the display system described in 1 above, both between the display element and the half mirror and between the half mirror and the reflecting section, the member that imparts the thickness direction phase difference may be located behind the phase difference member, and the first member may include a negative C plate. 4. In the display system described in 3 above, the negative C plate included in the first member may function as a protective layer for the absorptive polarizing film included in the polarizing member. 5. In the display system described in 4 above, the negative C plate included in the first member may be made of a cellulose-based resin. 6. In the display system described in any one of 1 to 5 above, the positive C plates included in the first phase difference member, the second phase difference member, the first member, and the second member may each have a surface smoothness of 1.0 arcmin or less. 7. In the display system described in any one of 1 to 6 above, the first optical stack including the polarizing member, the first phase difference member, and the first member, and the second optical stack including the reflecting section, the second phase difference member, and the second member may each have an ellipticity of 0.77 or more for transmitted light at a wavelength of 550 nm measured at a polar angle of 30° and an azimuth angle of 0° to 360°. 8. In the display system described in any one of 1 to 7 above, the first optical stack including the polarizing element, the first phase difference element, and the first element, and the second optical stack including the reflecting section, the second phase difference element, and the second element may each have an ellipticity of 0.94 or more for transmitted light at a wavelength of 550 nm measured at a polar angle of 0°. 9. In the display system described in any one of 1 to 8 above, the first optical stack including the polarizing element, the first phase difference element, and the first element, and the second optical stack including the reflecting section, the second phase difference element, and the second element, may each have a value (1-DI) obtained by subtracting the depolarization index (DI) of transmitted light at a wavelength of 550 nm measured at a polar angle of 0° from 1, which is 95.5% or more. 10. The display system according to any one of 1 to 9 above may further include a second lens portion disposed in front of the reflecting portion. 11. A display according to an embodiment of the present invention comprises the display system according to any one of 1 to 10 above. [Effects of the Invention]

[0007] According to the display system according to the embodiment of the present invention, it is possible to realize lightweight and high-definition VR goggles. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram showing a general configuration of a display system according to an embodiment of the present invention. [Figure 2] 2 is a diagram schematically illustrating an example of the positional relationship of members disposed between a display element and a reflector in the display system shown in FIG. 1. FIG. [Figure 3] 1. FIG. 4 is a diagram schematically illustrating another example of the positional relationship of members disposed between a display element and a reflector in the display system shown in FIG. [Figure 4] FIG. 10 is a diagram showing the luminance in the arrangement of the laminates of the examples and the comparative examples. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments. In order to clarify the description, the drawings may schematically show the width, thickness, shape, etc. of each part compared to the embodiments, but these are merely examples and do not limit the interpretation of the present invention. Furthermore, in the drawings, the same or equivalent elements are given the same reference numerals, and duplicate explanations may be omitted.

[0010] (Definition of terms and symbols) The definitions of terms and symbols used in this specification are as follows. (1) Refractive index (nx, ny, nz) "nx" is the refractive index in the direction in which the in-plane refractive index is greatest (i.e., the slow axis direction), "ny" is the refractive index in the direction perpendicular to the slow axis in the plane (i.e., the fast axis direction), and "nz" is the refractive index in the thickness direction. (2) In-plane phase difference (Re) "Re(λ)" is the in-plane retardation measured with light of wavelength λ nm at 23°C. For example, "Re(550)" is the in-plane retardation measured with light of wavelength 550 nm at 23°C. Re(λ) is calculated by the formula: Re(λ)=(nx-ny)×d, where d (nm) is the thickness of the layer (film). (3) Retardation in the thickness direction (Rth) "Rth(λ)" is the retardation in the thickness direction measured with light of wavelength λ nm at 23°C. For example, "Rth(550)" is the retardation in the thickness direction measured with light of wavelength 550 nm at 23°C. Rth(λ) is calculated by the formula: Rth(λ) = (nx - nz) × d, where d (nm) is the thickness of the layer (film). (4) Nz coefficient The Nz coefficient is calculated by Nz=Rth / Re. (5)Angle When angles are referred to herein, unless otherwise specified, the angles include both clockwise and counterclockwise angles relative to a reference direction. Thus, for example, "45°" means ±45°. Furthermore, in this specification, "substantially parallel" includes a range of 0°±10°, preferably within a range of 0°±5°, more preferably within a range of 0°±3°, and even more preferably within a range of 0°±1°. "Substantially perpendicular" includes a range of 90°±10°, preferably within a range of 90°±5°, more preferably within a range of 90°±3°, and even more preferably within a range of 90°±1°.

[0011] FIG. 1 is a schematic diagram showing the overall configuration of a display system according to one embodiment of the present invention. FIG. 1 schematically illustrates the arrangement and shape of each component of a display system 2. The display system 2 includes a display element 12, a reflector 14 including a reflective polarizing member, a first lens unit 16, a half mirror 18, a first retardation member 20, a second retardation member 22, and a second lens unit 24. The reflector 14 is disposed in front of the display surface 12a of the display element 12 and can reflect light emitted from the display element 12. The first lens unit 16 is disposed on the optical path between the display element 12 and the reflector 14, and the half mirror 18 is disposed between the display element 12 and the first lens unit 16. The first retardation member 20 is disposed on the optical path between the display element 12 and the half mirror 18, and the second retardation member 22 is disposed on the optical path between the half mirror 18 and the reflector 14.

[0012] The display element 12 is, for example, a liquid crystal display or an organic EL display, and has a display surface 12a for displaying an image. The light emitted from the display surface 12a passes through, for example, a polarizing member (typically, a polarizing film) that may be included in the display element 12, and is converted into first linearly polarized light.

[0013] The first phase difference member 20 can convert the first linearly polarized light incident on the first phase difference member 20 into first circularly polarized light. The first phase difference member 20 may be provided integrally with the display element 12.

[0014] The half mirror 18 transmits light emitted from the display element 12 and reflects light reflected by the reflecting portion 14 toward the reflecting portion 14. In the example shown in FIG. 1 , the half mirror 18 is provided integrally with the first lens portion 16.

[0015] The second phase difference member 22 can transmit light reflected by the reflecting unit 14 and the half mirror 18 through the reflecting unit 14, which includes a reflective polarizing member. The second phase difference member 22 may be provided integrally with the first lens unit 16, or may be provided integrally with the second lens unit 24. In the latter case, the second phase difference member 22 can be provided integrally with the second lens unit 24 together with the reflecting unit 14.

[0016] The first circularly polarized light emitted from the first phase difference member 20 passes through the half mirror 18 and the first lens unit 16 and is converted into the second linearly polarized light by the second phase difference member 22. The second linearly polarized light emitted from the second phase difference member 22 is reflected toward the half mirror 18 without passing through the reflective polarizing member included in the reflecting unit 14. At this time, the polarization direction of the second linearly polarized light incident on the reflective polarizing member included in the reflecting unit 14 is the same as the reflection axis of the reflective polarizing member. Therefore, the second linearly polarized light incident on the reflecting unit 14 is reflected by the reflective polarizing member.

[0017] The second linearly polarized light reflected by the reflecting unit 14 is converted into second circularly polarized light by the second phase difference member 22, and the second circularly polarized light emitted from the second phase difference member 22 passes through the first lens unit 16 and is reflected by the half mirror 18. The circularly polarized light reflected by the half mirror 18 passes through the first lens unit 16 and is converted into third linearly polarized light by the second phase difference member 22. The third linearly polarized light passes through the reflective polarizing member included in the reflecting unit 14. At this time, the polarization direction of the third linearly polarized light incident on the reflective polarizing member included in the reflecting unit 14 is the same direction as the transmission axis of the reflective polarizing member. Therefore, the third linearly polarized light incident on the reflecting unit 14 passes through the reflective polarizing member.

[0018] The light transmitted through the reflecting portion 14 passes through the second lens portion 24 and enters the eye 26 of the user.

[0019] For example, the absorption axis of the polarizing member included in the display element 12 and the reflection axis of the reflective polarizing member included in the reflecting section 14 may be arranged substantially parallel to each other or may be arranged substantially perpendicular to each other.

[0020] Although not shown in Fig. 1, the display system 2 may include a first member that provides a phase difference in the thickness direction and is disposed on the optical path between the display element 12 and the half mirror 18. The display system 2 may also include a second member that provides a phase difference in the thickness direction and is disposed on the optical path between the half mirror 18 and the reflecting section 14. By providing such a member, light leakage (for example, light leakage in an oblique direction) can be prevented. This also reduces the so-called ghost phenomenon, in which images are perceived as overlapping.

[0021] Figure 2 is a diagram schematically showing an example of the positional relationship of components arranged between the display element and the reflector of the display system shown in Figure 1, and Figure 3 is a diagram schematically showing another example of the positional relationship of components arranged between the display element and the reflector of the display system shown in Figure 1.

[0022] In the example shown in FIG. 2, a first retardation member 20 and a first member 30 that imparts a thickness direction retardation are arranged in this order in front of the polarizing member 10 included in the display element 12 (on the right side of FIG. 2). A second member 32 that imparts a thickness direction retardation and a second retardation member 22 are arranged in this order behind the reflecting section 14 (on the left side of FIG. 2). The members 30 and 32 that impart a thickness direction retardation are arranged in front of the retardation members 20 and 22, respectively. The polarizing member 10, the first retardation member 20, and the first member 30 may be stacked to form a first optical stack 100. The reflecting section 14, the second member 32, and the second retardation member 22 may be stacked to form a second optical stack 200. Although the first lens unit 16 and the half mirror 18 are not shown in FIG. 2, they are arranged, for example, between the first member 30 and the second retardation member 22.

[0023] In the example shown in FIG. 3 , a first member 30 that imparts a thickness direction retardation and a first phase difference member 20 are arranged in this order in front of the polarizing member 10 included in the display element 12 (on the right side of FIG. 2 ). A second phase difference member 22 and a second member 32 that imparts a thickness direction retardation are arranged in this order behind the reflecting section 14 (on the left side of FIG. 2 ). The members 30 and 32 that impart a thickness direction retardation are arranged behind the retarding members 20 and 22, respectively. The polarizing member 10, the first member 30, and the first phase difference member 20 may be stacked to form a first optical stack 100. The reflecting section 14, the second phase difference member 22, and the second member 32 may be stacked to form a second optical stack 200. Note that although the first lens unit 16 and the half mirror 18 are not shown in FIG. 3 , they are arranged, for example, between the first phase difference member 20 and the second member 32.

[0024] 2 and 3, when the first phase difference member 20 and the second phase difference member 22, and the first member 30 and the second member 32 are viewed as the same member, they are not arranged symmetrically with respect to the plane M indicated by the dashed line (they are arranged asymmetrically). By adopting such an arrangement, it is possible to more effectively prevent light leakage (for example, light leakage in oblique directions) and more effectively reduce the ghost phenomenon.

[0025] In one embodiment, an optical element set having a first optical stack 100 and a second optical stack 200 may be provided.

[0026] In each of the first optical stack 100 and the second optical stack 200 (hereinafter sometimes simply referred to as optical stacks), the components constituting the optical stack can be laminated via any appropriate adhesive layer. By laminating the components via adhesive layers, an optical stack with excellent smoothness can be obtained. In the above display system, the image can be enlarged in the lens section (for example, by a convex lens), and the smoothness of the optical stack can significantly affect visibility. An optical stack with excellent smoothness can achieve significantly excellent visibility in the above display system.

[0027] The adhesive layer may be formed of an adhesive agent or a pressure-sensitive adhesive. Specifically, the adhesive layer may be an adhesive layer or a pressure-sensitive adhesive layer. The thickness of the adhesive layer is, for example, 0.05 μm to 30 μm.

[0028] Each of the first phase difference member 20 and the second phase difference member 22 (hereinafter sometimes simply referred to as a phase difference member) may typically be a phase difference member that can convert linearly polarized light into circularly polarized light or circularly polarized light into linearly polarized light. The phase difference member may be composed of a single layer or may have a laminated structure.

[0029] When the retardation member is composed of a single layer, it may typically be a λ / 4 member. The in-plane retardation Re(550) of the λ / 4 member is, for example, 100 nm to 190 nm, or alternatively, 110 nm to 180 nm, 130 nm to 160 nm, or 135 nm to 155 nm.

[0030] The λ / 4 component preferably exhibits an inverse dispersion wavelength characteristic in which the retardation value increases with the wavelength of the measurement light. The Re(450) / Re(550) of the λ / 4 component is, for example, less than 1, and may be 0.95 or less, or even less than 0.90, or even 0.85 or less. The Re(450) / Re(550) of the λ / 4 component is, for example, 0.75 or more.

[0031] In one embodiment, the λ / 4 member satisfies all of Re(400) / Re(550) < 0.85, Re(650) / Re(550) > 1.03, and Re(750) / Re(550) > 1.05. The λ / 4 member preferably satisfies at least one selected from 0.65 < Re(400) / Re(550) < 0.80 (preferably, 0.7 < Re(400) / Re(550) < 0.75), 1.0 < Re(650) / Re(550) < 1.25 (preferably, 1.05 < Re(650) / Re(550) < 1.20), and 1.05 < Re(750) / Re(550) < 1.40 (preferably, 1.08 < Re(750) / Re(550) < 1.36), more preferably satisfies at least two, and still more preferably satisfies all of them.

[0032] The λ / 4 member preferably exhibits a refractive index characteristic of nx > ny ≧ nz. Here, "ny = nz" includes not only the case where ny and nz are exactly equal but also the case where they are substantially equal. Therefore, within a range that does not impair the effects of the present invention, ny < nz may occur. The Nz coefficient (Rth(590) / Re(590)) of the λ / 4 member is preferably 0.4 to 3, more preferably 0.4 to 2.5, still more preferably 0.4 to 1.5, and particularly preferably 0.4 to 1.3.

[0033] The λ / 4 member is formed of any suitable material that can satisfy the above characteristics. The λ / 4 member can be, for example, a stretched film of a resin film or an alignment cured layer of a liquid crystal compound. Note that a stretched film of a resin film may be referred to as a retardation film.

[0034] Examples of resins contained in the resin film include polycarbonate resins, polyester carbonate resins, polyester resins, polyvinyl acetal resins, polyarylate resins, cyclic olefin resins, cellulose resins, polyvinyl alcohol resins, polyamide resins, polyimide resins, polyether resins, polystyrene resins, and acrylic resins. These resins may be used alone or in combination (e.g., blends or copolymers). When the λ / 4 component exhibits reverse dispersion wavelength characteristics, resin films containing polycarbonate resins or polyester carbonate resins (hereinafter sometimes simply referred to as polycarbonate resins) can be suitably used.

[0035] Any suitable polycarbonate-based resin can be used as the polycarbonate-based resin as long as it can achieve the effects of the present invention. For example, the polycarbonate-based resin contains structural units derived from a fluorene-based dihydroxy compound, structural units derived from an isosorbide-based dihydroxy compound, and structural units derived from at least one dihydroxy compound selected from the group consisting of alicyclic diols, alicyclic dimethanols, di-, tri-, or polyethylene glycols, and alkylene glycols or spiroglycols. Preferably, the polycarbonate-based resin contains structural units derived from a fluorene-based dihydroxy compound, structural units derived from an isosorbide-based dihydroxy compound, structural units derived from an alicyclic dimethanol, and / or structural units derived from di-, tri-, or polyethylene glycol; more preferably, it contains structural units derived from a fluorene-based dihydroxy compound, structural units derived from an isosorbide-based dihydroxy compound, and structural units derived from di-, tri-, or polyethylene glycol. The polycarbonate-based resin may contain structural units derived from other dihydroxy compounds as needed. Details of polycarbonate-based resins suitable for use in λ / 4 components and methods for forming λ / 4 components are described, for example, in JP 2014-10291 A, JP 2014-26266 A, JP 2015-212816 A, JP 2015-212817 A, and JP 2015-212818 A, and the descriptions in these publications are incorporated herein by reference.

[0036] The above-mentioned liquid crystal compound alignment solidified layer is a layer in which the liquid crystal compound is aligned in a predetermined direction within the layer and the alignment state is fixed. The term "alignment solidified layer" encompasses an alignment solidified layer obtained by solidifying a liquid crystal monomer, as described below. In a λ / 4 component, rod-shaped liquid crystal compounds are typically aligned in the slow axis direction of the λ / 4 component (homogeneous alignment). Examples of rod-shaped liquid crystal compounds include liquid crystal polymers and liquid crystal monomers. The liquid crystal compound is preferably polymerizable. If the liquid crystal compound is polymerizable, the alignment state of the liquid crystal compound can be fixed by aligning the liquid crystal compound and then polymerizing it.

[0037] The alignment and solidification layer of the liquid crystal compound (liquid crystal alignment and solidification layer) can be formed by performing an alignment treatment on the surface of a predetermined substrate, applying a coating liquid containing a liquid crystal compound to the surface to align the liquid crystal compound in a direction corresponding to the alignment treatment, and fixing the alignment state. Any appropriate alignment treatment can be used as the alignment treatment. Specific examples include mechanical alignment treatment, physical alignment treatment, and chemical alignment treatment. Specific examples of mechanical alignment treatment include rubbing treatment and stretching treatment. Specific examples of physical alignment treatment include magnetic field alignment treatment and electric field alignment treatment. Specific examples of chemical alignment treatment include oblique vapor deposition and photoalignment treatment. Any appropriate treatment conditions can be used for the various alignment treatments depending on the purpose.

[0038] The alignment of liquid crystal compounds is achieved by treating them at a temperature at which they exhibit a liquid crystal phase depending on the type of liquid crystal compound. By performing such temperature treatment, the liquid crystal compounds assume a liquid crystal state and are aligned in accordance with the alignment treatment direction on the substrate surface.

[0039] In one embodiment, the alignment state is fixed by cooling the liquid crystal compound aligned as described above. When the liquid crystal compound is polymerizable or crosslinkable, the alignment state is fixed by subjecting the liquid crystal compound aligned as described above to a polymerization treatment or crosslinking treatment.

[0040] Any suitable liquid crystal polymer and / or liquid crystal monomer can be used as the liquid crystal compound. The liquid crystal polymer and the liquid crystal monomer can be used alone or in combination. Specific examples of liquid crystal compounds and methods for producing a liquid crystal alignment solidified layer are described in, for example, JP 2006-163343 A, JP 2006-178389 A, and WO 2018 / 123551 A. The descriptions in these publications are incorporated herein by reference.

[0041] The thickness of the λ / 4 member made of a stretched resin film is, for example, 10 μm to 100 μm, preferably 10 μm to 70 μm, more preferably 10 μm to 60 μm, and even more preferably 20 μm to 50 μm. The thickness of the λ / 4 member made of a liquid crystal alignment solidified layer is, for example, 1 μm to 10 μm, preferably 1 μm to 8 μm, more preferably 1 μm to 6 μm, and even more preferably 1 μm to 4 μm.

[0042] The angle between the absorption axis of the polarizing member 10 and the slow axis of the first phase difference member 20, which is a λ / 4 member, is, for example, 40° to 50°, or may be 42° to 48°, or may be about 45°. The angle between the absorption axis of the polarizing member 10 and the slow axis of the second phase difference member 22, which is a λ / 4 member, is, for example, 40° to 50°, or may be 42° to 48°, or may be about 45°.

[0043] When the retardation member has a laminated structure, the retardation member typically has a laminated structure including a λ / 2 layer and a λ / 4 layer.

[0044] The in-plane retardation Re(550) of the λ / 2 layer is, for example, 200 nm to 330 nm, may be 230 nm to 330 nm, may be 230 nm to 290 nm, or may be 250 nm to 280 nm.

[0045] The in-plane retardation Re(550) of the λ / 4 layer is, for example, 100 nm to 200 nm, or may be 110 nm to 180 nm, 130 nm to 160 nm, or 135 nm to 155 nm.

[0046] Each of the λ / 2 layer and the λ / 4 layer (hereinafter, may be simply referred to as the layer included in the laminated structure) preferably exhibits an inverse dispersion wavelength characteristic in which the retardation value increases according to the wavelength of the measurement light. Re(450) / Re(550) of the layer included in the laminated structure is, for example, 0.75 or more and less than 1, and may be 0.8 or more and 0.95 or less.

[0047] The layer included in the laminated structure may exhibit flat wavelength dispersion characteristics in which the retardation value hardly changes depending on the wavelength of the measurement light. In this case, Re(450) / Re(550) of the layer included in the laminated structure may be, for example, 0.99 to 1.03, and Re(650) / Re(550) may be, for example, 0.98 to 1.02.

[0048] The layer included in the laminated structure preferably exhibits a refractive index characteristic showing a relationship of nx>ny≧nz. Here, "ny = nz" includes not only the case where ny and nz are exactly equal, but also the case where they are substantially equal. Therefore, within a range that does not impair the effects of the present invention, ny < nz may occur. The Nz coefficient (Rth(550) / Re(550)) of the layer included in the laminated structure is preferably 0.4 to 3, more preferably 0.4 to 2.5, still more preferably 0.4 to 1.5, and particularly preferably 0.4 to 1.3.

[0049] The layer included in the laminated structure is formed of any suitable material that can satisfy the above characteristics. The layer included in the laminated structure may be, for example, a stretched film of a resin film or an alignment cured layer of a liquid crystal compound. Details of the stretched film of the resin film and the alignment cured layer of the liquid crystal compound are as described above. When the layer included in the laminated structure has flat wavelength dispersion characteristics, preferred examples of the forming material include cycloolefin-based resins, particularly norbornene-based resins.

[0050] Norbornene resins are resins polymerized using norbornene monomers as polymerization units. Examples of norbornene monomers include norbornene and its alkyl and / or alkylidene substituted derivatives such as 5-methyl-2-norbornene, 5-dimethyl-2-norbornene, 5-ethyl-2-norbornene, 5-butyl-2-norbornene, and 5-ethylidene-2-norbornene, as well as polar group-substituted derivatives thereof such as halogen; dicyclopentadiene; 2,3-dihydrodicyclopentadiene; Dimethanooctahydronaphthalene, its alkyl and / or alkylidene substituted derivatives, and polar group substituted derivatives such as halogen, for example, 6-methyl-1,4:5,8-dimethano-1,4,4a,5,6,7,8,8a-octahydronaphthalene, 6-ethyl-1,4:5,8-dimethano-1,4,4a,5,6,7,8,8a-octahydronaphthalene, 6-ethylidene-1,4:5,8-dimethano-1,4,4a,5,6, 7,8,8a-Octahydronaphthalene, 6-Chloro-1,4:5,8-dimethano-1,4,4a,5,6,7,8,8a-octahydronaphthalene, 6-Cyano-1,4:5,8-dimethano-1,4,4a,5,6,7,8,8a-octahydronaphthalene, 6-Pyridyl-1,4:5,8-dimethano-1,4,4a,5,6,7,8,8a-octahydronaphthalene, 6-Methoxycarbonyl-1,4:5,8-dimethano and trimers and tetramers of cyclopentadiene, such as 4,9:5,8-dimethano-3a,4,4a,5,8,8a,9,9a-octahydro-1H-benzoindene and 4,11:5,10:6,9-trimethano-3a,4,4a,5,5a,6,9,9a,10,10a,11,11a-dodecahydro-1H-cyclopentaanthracene. The norbornene-based resin may be a copolymer of a norbornene-based monomer and another monomer.

[0051] The thickness of the λ / 4 layer can be applied to the above-mentioned λ / 4 member. The thickness of the λ / 2 layer formed of a stretched resin film is, for example, 20 μm to 200 μm, preferably 20 μm to 140 μm, more preferably 20 μm to 120 μm, and even more preferably 40 μm to 100 μm. The thickness of the λ / 2 layer formed of a liquid crystal alignment solidified layer is, for example, 2 μm to 20 μm, preferably 2 μm to 16 μm, more preferably 2 μm to 12 μm, and even more preferably 2 μm to 8 μm.

[0052] In the retardation member, the angle between the slow axis of the λ / 2 layer and the slow axis of the λ / 4 layer is preferably 50° to 70°, more preferably 55° to 65°, even more preferably 57° to 63°, and particularly preferably about 60°. In one embodiment, the angle between the absorption axis of the polarizing member 10 and the slow axis of the λ / 2 layer is preferably 5° to 35°, more preferably 10° to 20°, even more preferably 12° to 18°, and particularly preferably about 15°. The angle between the absorption axis of the polarizing member 10 and the slow axis of the λ / 4 layer is preferably 55° to 85°, more preferably 70° to 80°, even more preferably 72° to 78°, and particularly preferably about 75°. In another embodiment, the angle between the absorption axis of the polarizing member 10 and the slow axis of the λ / 4 layer is preferably 5° to 35°, more preferably 10° to 20°, even more preferably 12° to 18°, and particularly preferably about 15°. The angle between the absorption axis of the polarizing member 10 and the slow axis of the λ / 2 layer is preferably 55° to 85°, more preferably 70° to 80°, even more preferably 72° to 78°, and particularly preferably about 75°.

[0053] The first phase difference member 20 and the second phase difference member 22 may be members having the same configuration (forming material, thickness, optical properties, etc.) or may be members having different configurations. For example, from the viewpoint of manufacturing efficiency, the first phase difference member 20 and the second phase difference member 22 may have the same configuration.

[0054] In the display system 2, for example, from the viewpoint of improving visibility, a high degree of adjustment may be required between the retardation values ​​of the first retardation member 20 and the second retardation member 22. For example, the absolute value of the difference between the in-plane retardation (a) of the first retardation member 20 and the in-plane retardation (b) of the second retardation member 22 is, for example, 3.5 nm or less, preferably 3.0 nm or less, more preferably 2.5 nm or less, even more preferably 2.0 nm or less, particularly preferably 1.5 nm or less, and most preferably 1.0 nm or less. (a) and (b) are, for example, values ​​of Re(590).

[0055] Furthermore, for example, it is preferable that the in-plane retardation (a) of the first retardation member 20 and the in-plane retardation (b) of the second retardation member 22 satisfy the following formula (I). ((a)-(b)) / ((a)+(b) / 2)≦0.02···(I) More preferably, ((a)-(b)) / ((a)+(b) / 2)≦0.015, and even more preferably, ((a)-(b)) / ((a)+(b) / 2)≦0.01.

[0056] Each of the first and second components 30 and 32 (hereinafter, simply referred to as components imparting a thickness-direction retardation) includes a component (a so-called positive C-plate) whose refractive index characteristics can exhibit the relationship nz > nx = ny. In the example shown in FIG. 2, the first component 30 may be a positive C-plate. The second component 32 may include, in addition to the positive C-plate 32a, a component (a so-called negative C-plate) 32b whose refractive index characteristics can exhibit the relationship nx = ny > nz. Here, "nx = ny" encompasses not only the case where nx and ny are strictly equal, but also the case where nx and ny are substantially equal. The second component 32 may have a laminated structure in which the positive C-plate 32a and the negative C-plate 32b are laminated via any suitable adhesive layer (not shown). In the example shown in FIG. 2, the negative C-plate 32b is disposed forward of the positive C-plate 32a, but the arrangement may be reversed.

[0057] In the example shown in Fig. 3, the second member 32 may be a positive C plate. The first member 30 may include a negative C plate 30b in addition to the positive C plate 30a. The second member 32 may have, for example, a laminated structure in which the positive C plate 30a and the negative C plate 30b are laminated via any appropriate adhesive layer (not shown). In the example shown in Fig. 3, the positive C plate 30a is disposed in front of the negative C plate 30b, but their positions may be reversed.

[0058] The thickness direction retardation Rth(590) of the positive C plate is, for example, -10 nm or less, preferably -30 nm or less, more preferably -50 nm or less, even more preferably -60 nm or less, particularly preferably -70 nm or less, and may be -80 nm or less, or may be -90 nm or less. On the other hand, the thickness direction retardation Rth(590) of the positive C plate is, for example, -200 nm or more, more preferably -190 nm or more, even more preferably -180 nm or more, or may be -160 nm or more. The in-plane retardation Re(550) of the positive C plate is, for example, less than 10 nm.

[0059] The positive C plate may be made of any suitable material that can satisfy the desired characteristics, and may be, for example, a resin film or an alignment-solidified layer of a liquid crystal compound.

[0060] A typical example of a material for the resin film constituting the positive C plate is a resin material having negative birefringence. A resin having negative birefringence is a resin that exhibits the property that, when uniaxially stretched, the refractive index in the direction perpendicular to the stretching direction is maximized. Examples of resins having negative birefringence include resins having chemical bonds or functional groups with large polarization anisotropy, such as aromatic rings or carbonyl groups, introduced into the side chain. Specific examples of resins having negative birefringence include acrylic resins, styrene resins, maleimide resins, modified polyolefin resins, and fumarate ester resins. Specific examples of resins having negative birefringence include those described in JP 2021-076759 A, JP 2008-544304 A, and JP 2008-544317 A. The above resin materials can be used alone or in combination of two or more.

[0061] The resin film constituting the positive C plate may further contain any appropriate additives as necessary. Specific examples of additives include plasticizers, heat stabilizers, light stabilizers, lubricants, antioxidants, UV absorbers, flame retardants, colorants, antistatic agents, compatibilizers, crosslinking agents, thickeners, etc. The type and content of additives may be appropriately determined depending on the purpose. The content of additives in the resin film is, for example, about 3% to 10% by weight.

[0062] In one embodiment, the resin material can be formed into a film and then used as a positive C plate as is. Specifically, the formed film can be used as a positive C plate as is without stretching. For example, when a resin solution containing the resin material is applied to a support (by a solution casting method) to form a film, stress occurs due to volume shrinkage when the resin solution dries on the support, and the polymer molecular chains tend to be oriented in the in-plane direction. When a resin material that exhibits high birefringence and negative intrinsic birefringence is used, a coating film with large thickness-direction birefringence can be formed on the support due to the shrinkage action during drying. The formed coating film can then be used as a positive C plate as is.

[0063] The thickness of the positive C plate made of a resin film is, for example, 1 μm to 40 μm, preferably 3 μm to 35 μm, and more preferably 5 μm to 30 μm.

[0064] A preferred example of the alignment layer of a liquid crystal compound constituting the positive C-plate is an alignment layer of a liquid crystal material fixed in homeotropic alignment. The liquid crystal material (liquid crystal compound) that can be homeotropically aligned may be a liquid crystal monomer or a liquid crystal polymer. Specific examples of such liquid crystal compounds and methods for forming a positive C-plate include the liquid crystal compounds and methods for forming the retardation layer described in

[0020] to

[0028] of JP 2002-333642 A.

[0065] The thickness of the positive C plate formed of an aligned and solidified layer of a liquid crystal compound is preferably 0.5 μm to 10 μm, more preferably 0.5 μm to 8 μm, and even more preferably 0.5 μm to 5 μm.

[0066] The positive C plate included in the first component 30 and the positive C plate included in the second component 32 may have the same configuration (material, thickness, optical properties, etc.) or different configurations. For example, from the viewpoint of manufacturing efficiency, the positive C plate included in the first component 30 and the positive C plate included in the second component 32 may have the same configuration.

[0067] The thickness direction retardation Rth(590) of the negative C plate is, for example, 10 nm or more, or may be 15 nm or more, 20 nm or more, or 25 nm or more. On the other hand, the thickness direction retardation Rth(590) of the negative C plate is preferably 70 nm or less, more preferably 60 nm or less, and even more preferably 50 nm or less. The in-plane retardation Re(550) of the negative C plate is, for example, less than 10 nm.

[0068] By combining a positive C-plate and a negative C-plate to form a member that provides thickness retardation, it is possible to adjust the wavelength dispersion characteristics of each of the positive C-plate and the negative C-plate, and the desired wavelength dispersion characteristics can be achieved for the entire member that provides thickness retardation. For example, the Rth(450) / Rth(550) of the positive C-plate is preferably 0.8 or more, more preferably 0.9 to 1.1. The Rth(450) / Rth(550) of the negative C-plate is preferably 0.7 or more, more preferably 0.8 to 1.1.

[0069] The negative C plate may be made of any suitable material that satisfies the above-mentioned characteristics, and may preferably be a resin film.

[0070] The resin film constituting the negative C plate is typically made of a resin material having positive birefringence. The negative C plate may be a stretched film or an unstretched film. For example, the negative C plate may be made of a cellulose-based resin.

[0071] The cellulose-based resin is not particularly limited, but is preferably a cellulose organic acid ester or a cellulose mixed organic acid ester in which some or all of the hydroxyl groups of cellulose are substituted with acetyl groups, propionyl groups, and / or butyl groups. Examples of the cellulose organic acid ester include cellulose acetate, cellulose propionate, and cellulose butyrate. Examples of the cellulose mixed organic acid ester include cellulose acetate propionate and cellulose acetate butyrate. The cellulose-based resin can be obtained, for example, by the method described in Japanese Patent Application Laid-Open No. 2001-188128, paragraphs

[0040] and

[0041] .

[0072] The degree of substitution of the cellulose-based resin (the number of hydroxyl groups attached to the 2nd, 3rd, and 6th carbon atoms in the cellulose skeleton) is not particularly limited. The degree of acetyl substitution can be determined according to ASTM-D817-91 (Testing Methods for Cellulose Acetate, etc.). The degree of propionyl substitution can be determined according to ASTM-D817-96 (Testing Methods for Cellulose Acetate, etc.).

[0073] The weight-average molecular weight (Mw) of the cellulose-based resin, as measured by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent, is preferably 20,000 to 1,000,000, and more preferably 25,000 to 800,000. The glass transition temperature (Tg) of the cellulose-based resin is preferably 110°C to 185°C. A Tg of 110°C or higher facilitates the production of a film with good thermal stability, while a Tg of 185°C or lower provides excellent moldability. The glass transition temperature (Tg) can be determined by DSC in accordance with JIS K 7121:1987.

[0074] A negative C plate made of a cellulose-based resin can be obtained by any appropriate molding method. Preferably, a negative C plate made of a cellulose-based resin is produced by stretching a polymer film formed into a sheet shape by solvent casting or melt extrusion using a transverse uniaxial stretching method, a longitudinal and transverse simultaneous biaxial stretching method, or a longitudinal and transverse sequential biaxial stretching method. The temperature at which the polymer film is stretched (stretching temperature) is preferably 120°C to 200°C. The stretching ratio (stretching ratio) at which the polymer film is stretched is preferably more than 1 and not more than 3 times. Note that commercially available films can be used as they are as negative C plates made of a cellulose-based resin. Alternatively, commercially available films that have been subjected to secondary processing such as stretching and / or shrinking can also be used as negative C plates made of a cellulose-based resin.

[0075] The thickness of the negative C plate made of a cellulose-based resin is, for example, 10 μm to 105 μm, preferably 15 μm to 100 μm, and more preferably 20 μm to 95 μm.

[0076] Furthermore, for example, the negative C plate may be made of a polyimide resin. When polyimide resin is formed into a sheet by solvent casting, the molecules tend to spontaneously orient during the solvent evaporation process, making it possible to produce a very thin member whose refractive index characteristics exhibit the relationship nx=ny>nz. The negative C plate may be obtained by stretching a film formed by solvent casting using a longitudinal uniaxial stretching method or a transverse uniaxial stretching method. The film stretching temperature is preferably 120°C to 200°C. The film stretching ratio is preferably more than 1 and not more than 3 times. The thickness of a negative C plate made of a polyimide resin is preferably 0.5 μm to 10 μm, and more preferably 1 μm to 5 μm.

[0077] Preferably, the polyimide resin has a hexafluoroisopropylidene group and / or a trifluoromethyl group. More preferably, the polyimide resin has at least a repeating unit represented by the following general formula (I) or a repeating unit represented by the following general formula (II). Polyimide resins containing these repeating units have excellent solubility in common solvents, and can be formed into films by solvent casting. Furthermore, a thin layer of polyimide resin can be formed on a substrate with poor solvent resistance, such as a triacetyl cellulose film, without excessively corroding the surface. [ka] [ka]

[0078] In the above general formulas (I) and (II), G and G' represent groups independently selected from the group consisting of a covalent bond, a CH2 group, a C(CH3)2 group, a C(CF3)2 group, a C(CX3)2 group (where X is a halogen), a CO group, an O atom, an S atom, a SO2 group, a Si(CH2CH3)2 group, and an N(CH3) group, and may be the same or different.

[0079] In the above general formula (I), L is a substituent, and e represents the number of substitutions. L is, for example, a halogen, an alkyl group having 1 to 3 carbon atoms, a halogenated alkyl group having 1 to 3 carbon atoms, a phenyl group, or a substituted phenyl group, and when there are multiple Ls, they may be the same or different. e is an integer from 0 to 3.

[0080] In the general formula (II), Q is a substituent, and f represents the number of substitutions. Q is, for example, an atom or group selected from the group consisting of hydrogen, halogen, alkyl group, substituted alkyl group, nitro group, cyano group, thioalkyl group, alkoxy group, aryl group, substituted aryl group, alkyl ester group, and substituted alkyl ester group, and when there are multiple Qs, they may be the same or different. f is an integer from 0 to 4, and g and h are each integers from 1 to 3.

[0081] The polyimide resin can be obtained, for example, by reacting a tetracarboxylic dianhydride with a diamine. The repeating unit of general formula (I) can be obtained, for example, by using 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl as the diamine and reacting it with a tetracarboxylic dianhydride having at least two aromatic rings. The repeating unit of general formula (II) can be obtained, for example, by using 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropanoic dianhydride as the tetracarboxylic dianhydride and reacting it with a diamine having at least two aromatic rings. The reaction can be, for example, chemical imidization, which proceeds in two steps, or thermal imidization, which proceeds in one step.

[0082] Examples of the tetracarboxylic dianhydride include 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropanoic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,3,3',4-benzophenonetetracarboxylic dianhydride, 2,2',3,3'-benzophenonetetracarboxylic dianhydride, 2,2'-dibromo-4,4',5,5'-biphenyltetracarboxylic dianhydride, 2,2'-bis(trifluoromethyl) Examples of suitable dianhydrides include 4,4'-bis(3,4-dicarboxyphenyl)ether dianhydride, 4,4'-oxydiphthalic dianhydride, 4,4'-bis(3,4-dicarboxyphenyl)sulfonic dianhydride, bis(2,3-dicarboxyphenyl)methane dianhydride, and bis(3,4-dicarboxyphenyl)diethylsilane dianhydride.

[0083] Examples of the diamine include 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 4,4'-diaminobiphenyl, 4,4'-diaminophenylmethane, 4,4'-(9-fluorenylidene)-dianiline, 3,3'-dichloro-4,4'-diaminodiphenylmethane, 2,2'-dichloro-4,4'-diaminobiphenyl, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, and 4,4'-diaminodiphenyl thioether.

[0084] The polyimide resin preferably has a weight-average molecular weight (Mw) of 20,000 to 180,000 based on polyethylene oxide standard when dimethylformamide solution (10 mM lithium bromide and 10 mM phosphoric acid are added and made up to 1 L of dimethylformamide solution) is used as a developing solvent, and the imidization rate is preferably 95% or higher. The imidization rate can be determined from the integrated intensity ratio of the proton peak derived from polyamic acid, which is a polyimide precursor, to the proton peak derived from polyimide.

[0085] Furthermore, for example, the negative C plate may be made of a polyarylate resin. A polyarylate resin having a predetermined substituent group exhibits high birefringence, and a coating film obtained by applying a resin solution of this polymer to a substrate can be used as the negative C plate. Details of the polyarylate resin having a predetermined substituent group are described, for example, in JP 2009-80440 A, and the descriptions of these publications are incorporated herein by reference.

[0086] The negative C plate 30b included in the first member 30 can suitably function as a protective layer for the absorptive polarizing film described below.

[0087] The surface smoothness of the retardation member and the member (e.g., a positive C-plate and / or a negative C-plate) included in the member imparting thickness-direction retardation is, for example, 1.0 arcmin or less, preferably 0.50 arcmin or less, more preferably 0.40 arcmin or less, even more preferably 0.30 arcmin or less, and particularly preferably 0.20 arcmin or less. Within this range, a display system with excellent visibility can be realized. For example, by satisfying such surface smoothness, the uniformity of the retardation value can be improved, and as a result, a display system with excellent display characteristics can be obtained.

[0088] The thickness variation of the retardation member and the member imparting retardation in the thickness direction (e.g., a positive C-plate and / or a negative C-plate) is preferably 1 μm or less, more preferably 0.8 μm or less, even more preferably 0.6 μm or less, and even more preferably 0.4 μm or less. Such thickness variation can, for example, achieve the above-mentioned surface smoothness. Here, the thickness variation can be determined by measuring the thickness of a first portion located within the surface of the object to be measured and the thickness at a predetermined distance (e.g., 5 mm to 15 mm) from the first portion in any direction (e.g., upward, downward, leftward, and rightward) from the first portion.

[0089] The polarizing member 10 may be an absorptive polarizing member including a resin film containing a dichroic material (sometimes referred to as an absorptive polarizing film). The absorptive polarizing member typically has a laminated structure of an absorptive polarizing film and a protective layer.

[0090] The thickness of the absorptive polarizing film is, for example, 1 μm or more and 20 μm or less, or may be 2 μm or more and 15 μm or less, or may be 12 μm or less, or 10 μm or less, or 8 μm or less, or may be 5 μm or less.

[0091] The absorptive polarizing film may be made from a single layer of resin film or may be made from a laminate of two or more layers.

[0092] When fabricating from a single-layer resin film, an absorptive polarizing film can be obtained by dyeing a hydrophilic polymer film such as a polyvinyl alcohol (PVA) film, a partially formalized PVA film, or a partially saponified ethylene-vinyl acetate copolymer film with iodine or a dichroic substance such as a dichroic dye, stretching, etc. Among these, an absorptive polarizing film obtained by dyeing a PVA film with iodine and uniaxially stretching it is preferred.

[0093] The dyeing with iodine is carried out, for example, by immersing the PVA film in an aqueous iodine solution. The stretching ratio of the uniaxial stretching is preferably 3 to 7 times. The stretching may be carried out after the dyeing treatment or while dyeing. Alternatively, the stretching may be followed by dyeing. If necessary, the PVA film may be subjected to a swelling treatment, a crosslinking treatment, a washing treatment, a drying treatment, etc.

[0094] Examples of laminates produced using the two or more layer laminate include a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or a laminate of a resin substrate and a PVA-based resin layer formed by coating on the resin substrate. An absorptive polarizing film obtained using a laminate of a resin substrate and a PVA-based resin layer formed by coating on the resin substrate can be produced, for example, by applying a PVA-based resin solution to the resin substrate and drying the resin substrate to form a PVA-based resin layer on the resin substrate, thereby obtaining a laminate of the resin substrate and the PVA-based resin layer; and then stretching and dyeing the laminate to convert the PVA-based resin layer into an absorptive polarizing film. In this embodiment, a polyvinyl alcohol-based resin layer containing a halide and a polyvinyl alcohol-based resin is preferably formed on one side of the resin substrate. The stretching typically involves immersing the laminate in an aqueous boric acid solution and stretching it. Furthermore, the stretching may further include, if necessary, in-air stretching of the laminate at an elevated temperature (e.g., 95°C or higher) before stretching in the aqueous boric acid solution. Additionally, in this embodiment, the laminate is preferably subjected to a drying shrinkage treatment by heating while being transported in the longitudinal direction, thereby shrinking the laminate by 2% or more in the width direction. Typically, the manufacturing method of this embodiment includes subjecting the laminate to an in-air auxiliary stretching treatment, a dyeing treatment, an underwater stretching treatment, and a drying shrinkage treatment, in this order. By introducing auxiliary stretching, it is possible to increase the crystallinity of PVA, even when PVA is coated on a thermoplastic resin, thereby achieving high optical properties. Furthermore, by simultaneously increasing the orientation of PVA in advance, problems such as a decrease in orientation or dissolution of PVA when immersed in water in the subsequent dyeing and stretching steps can be prevented, thereby achieving high optical properties. Furthermore, when the PVA-based resin layer is immersed in a liquid, the disordering of the orientation of polyvinyl alcohol molecules and the decrease in orientation can be suppressed compared to when the PVA-based resin layer does not contain a halide. This can improve the optical properties of an absorptive polarizing film obtained through treatment steps, such as dyeing and underwater stretching, in which the laminate is immersed in a liquid. Furthermore, the optical properties can be improved by shrinking the laminate in the width direction through drying shrinkage treatment.The obtained resin substrate / absorptive polarizing film laminate may be used as is (i.e., the resin substrate may be used as a protective layer for the absorptive polarizing film), or any suitable protective layer may be laminated depending on the purpose on the surface obtained by peeling the resin substrate from the resin substrate / absorptive polarizing film laminate, or on the surface opposite to the peeled surface. Details of such methods for producing absorptive polarizing films are described in, for example, JP 2012-73580 A and Japanese Patent No. 6470455 A. The entire disclosures of these publications are incorporated herein by reference.

[0095] The crossed transmittance (Tc) of the absorptive polarizing film (absorptive polarizing member) is preferably 0.5% or less, more preferably 0.1% or less, and even more preferably 0.05% or less. The single transmittance (Ts) of the absorptive polarizing film (absorptive polarizing member) is, for example, 41.0% to 45.0%, and preferably 42.0% or more. The polarization degree (P) of the absorptive polarizing film (absorptive polarizing member) is, for example, 99.0% to 99.997%, and preferably 99.9% or more.

[0096] The protective layer that can be included in the absorptive polarizing member can be composed of any appropriate film. Examples of materials that can be used as the main component of the film that constitutes the protective layer include cellulose-based resins such as triacetyl cellulose (TAC), polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, polyimide-based, polyethersulfone-based, polysulfone-based, polystyrene-based, cycloolefin-based resins such as polynorbornene, polyolefin-based, (meth)acrylic-based, and acetate-based resins.

[0097] The thickness of the protective layer is preferably 5 μm to 80 μm, more preferably 10 μm to 50 μm, and even more preferably 15 μm to 40 μm. The surface smoothness of the protective layer is preferably 0.7 arcmin or less, more preferably 0.6 arcmin or less, and even more preferably 0.5 arcmin or less.

[0098] The reflective polarizing element included in the reflector 14 transmits light polarized parallel to its transmission axis (typically, linearly polarized light) while maintaining its polarization state, and can reflect light polarized in other states (typically, light polarized perpendicular to its transmission axis). The reflective polarizing element is typically made of a film (sometimes referred to as a reflective polarizing film) having a multilayer structure. The thickness of the reflective polarizing film is, for example, 10 μm to 150 μm, preferably 20 μm to 100 μm, and more preferably 30 μm to 60 μm.

[0099] Commercially available reflective polarizing films include, for example, "DBEF" and "APF" manufactured by 3M, and "APCF" manufactured by Nitto Denko Corporation.

[0100] The crossed transmittance (Tc) of the reflective polarizing member (reflective polarizing film) can be, for example, 0.01% to 3%. The single transmittance (Ts) of the reflective polarizing member (reflective polarizing film) can be, for example, 43% to 49%, preferably 45% to 47%. The polarization degree (P) of the reflective polarizing member (reflective polarizing film) can be, for example, 92% to 99.99%.

[0101] The reflective section 14 may include an absorptive polarizing element in addition to a reflective polarizing element. The absorptive polarizing element may be disposed in front of the reflective polarizing element. The reflection axis of the reflective polarizing element and the absorption axis of the absorptive polarizing element may be disposed approximately parallel to each other, and the transmission axis of the reflective polarizing element and the transmission axis of the absorptive polarizing element may be disposed approximately parallel to each other. When the reflective section 14 includes an absorptive polarizing element, the reflective section 14 may include a laminate having a reflective polarizing element and an absorptive polarizing element.

[0102] The optical laminate preferably has an ellipticity of 0.77 or more, more preferably 0.78 or more, even more preferably 0.80 or more, particularly preferably 0.82 or more, and most preferably 0.84 or more, for transmitted light at a wavelength of 550 nm, measured at a polar angle of 30° and an azimuth angle of 0° to 360°. By using an optical laminate exhibiting such an ellipticity, a display system with excellent display characteristics can be obtained. Such an optical laminate can reduce ghosting in the display system. It can also suppress light leakage and contribute to higher resolution. The higher the ellipticity of the optical laminate for transmitted light at a wavelength of 550 nm, measured at a polar angle of 30° and an azimuth angle of 0° to 360°, the better, with the upper limit being, for example, 0.90 (preferably 0.93, more preferably 0.95, and even more preferably 0.99). Here, "ellipticity" refers to the ratio of the minor axis to the major axis of circularly polarized light, and is an absolute value. For example, the ellipticity of perfectly circularly polarized light is 1, and the ellipticity of perfectly linearly polarized light is 0.

[0103] In one embodiment, the ellipticity of transmitted light of a predetermined wavelength measured at a polar angle of 30° and an azimuth angle of 0° to 360° is the ellipticity measured at every 11.25° azimuth angle in the range of 0° to 360° for light of the predetermined wavelength incident from the polarizing member side at a polar angle of 30° and emitted at a polar angle of 30°. Therefore, "the ellipticity is X or more" measured at an azimuth angle of 0° to 360° means that the minimum value of the 32 measured values ​​obtained is X.

[0104] The optical laminate preferably has an ellipticity of 0.94 or more, more preferably 0.95 or more, and even more preferably 0.96 or more, for transmitted light at a wavelength of 550 nm measured at a polar angle of 0° (front direction). Within this range, an optical laminate can be obtained that exhibits significant effects in reducing ghosting, suppressing light leakage, and achieving high definition. The higher the ellipticity of the optical laminate for transmitted light at a wavelength of 550 nm measured at a polar angle of 0° (front direction), the better, with the upper limit being, for example, 0.99 (preferably 1).

[0105] The ellipticity is measured, for example, using a Mueller matrix polarimeter (manufactured by Axometrics, product name "Axoscan") at 23°C by irradiating light of a predetermined wavelength (e.g., 550 nm) from the polarizing member side of the optical laminate.

[0106] The value (1-DI) obtained by subtracting the depolarization index (DI) of the optical laminate from 1 is preferably 60% or more. The depolarization index (DI) can be determined by measuring the Mueller matrix ((1) below) representing the polarization effect and using the following formula (2). The Mueller matrix representing the polarization effect can be measured, for example, using a Mueller matrix polarimeter (manufactured by Axometrics, product name "Axoscan") at 23°C by irradiating light of a predetermined wavelength (e.g., 550 nm) onto the polarizing member side of the optical laminate.

number

[0107] The optical laminate preferably has a value (1-DI) obtained by subtracting the depolarization index (DI) of transmitted light at a wavelength of 550 nm measured at a polar angle of 30° and an azimuth angle of 0° to 360° from 1, where DI is 99.68% or more. Here, the depolarization index (DI) of a predetermined wavelength measured at a polar angle of 30° and an azimuth angle of 0° to 360° is the average value of depolarization indices measured at azimuth angles of 11.25° in the range of 0° to 360° for light of a predetermined wavelength incident on the polarizing member side of the optical laminate at a polar angle of 30° and the emitted light at a polar angle of 30°. The optical laminate preferably has a value (1-DI) obtained by subtracting the depolarization index (DI) of transmitted light at a wavelength of 550 nm measured at a polar angle of 0° (front direction) from 1, where DI is 99.5% or more, and more preferably 99.75% or more. [Example]

[0108] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The test and evaluation methods used in the examples are as follows.

[0109] (1) Thickness Thicknesses of 10 μm or less were measured using a scanning electron microscope (manufactured by JEOL Ltd., product name "JSM-7100F"), and thicknesses of more than 10 μm were measured using a digital micrometer (manufactured by Anritsu Corporation, product name "KC-351C"). (2) Phase difference value The retardation value at a predetermined wavelength was measured at 23° C. using a retardation / ellipsoidal polarization measuring device (manufactured by Oji Scientific Instruments, product names "KOBRA-HBR" and "KOBRA-HBPR"). (3) Single transmittance and polarization degree of polarizing film The polarizing film's single transmittance Ts, parallel transmittance Tp, and crossed transmittance Tc were measured using a spectrophotometer (Otsuka Electronics Co., Ltd., "LPF-200"). Ts, Tp, and Tc are Y values ​​measured using a 2-degree visual field (C light source) according to JIS Z8701 and corrected for luminosity. The polarization degree of the polarizing film was calculated from the obtained Tp and Tc using the following formula: Degree of polarization (%)={(Tp-Tc) / (Tp+Tc)} 1 / 2 ×100 (4) Surface smoothness Surface smoothness was measured using a phase-shifting laser interferometer (manufactured by Zygo, product name "DynaFiz"). Specifically, the measurement object was laminated onto a microslide glass (manufactured by Matsunami Glass Industry Co., Ltd., product name "S200200") to prevent the inclusion of foreign matter, bubbles, or deformation lines. Next, degassing was performed using a pressure degassing device (autoclave) to remove the influence of minute bubbles. The degassing conditions were 50°C, 0.5 MPa, and 30 minutes. After degassing, the sample was allowed to cool at room temperature for at least 30 minutes to obtain a measurement sample. The sample was placed on a vibration-isolating measurement table, and a single-wavelength (633 nm) laser was used to interfere with a standard whose flatness was guaranteed, measuring the relative displacement within a specified area (a circle of 30 mm diameter).For analysis, the surface smoothness (unit: arcmin) was defined as doubling the "Slope magnitude RMS" angle index obtained by extracting frequency values ​​from 0.1 / mm to 1 / mm (equivalent to 2σ).

[0110] [Production Example 1: Preparation of Retardation Film] Into a batch polymerization apparatus consisting of two vertical reactors equipped with stirring blades and reflux condensers controlled at 100°C, 29.60 parts by weight (0.046 mol) of bis[9-(2-phenoxycarbonylethyl)fluoren-9-yl]methane, 29.21 parts by weight (0.200 mol) of isosorbide (ISB), 42.28 parts by weight (0.139 mol) of spiroglycol (SPG), 63.77 parts by weight (0.298 mol) of diphenyl carbonate (DPC), and 1.19 × 10 mol of calcium acetate monohydrate as a catalyst were added. -2 Weight part (6.78×10 -5 (mol) was charged. After purging the reactor with nitrogen under reduced pressure, heating was performed using a heat transfer medium. Stirring was initiated when the internal temperature reached 100°C. Forty minutes after the start of the temperature increase, the internal temperature reached 220°C. This temperature was maintained while simultaneously reducing the pressure. 90 minutes after reaching 220°C, the pressure was reduced to 13.3 kPa. Phenol vapor by-produced during the polymerization reaction was introduced into a reflux condenser at 100°C, and the small amount of monomer components contained in the phenol vapor was returned to the reactor. Uncondensed phenol vapor was collected by introducing nitrogen into the first reactor and temporarily restoring the pressure to atmospheric pressure. The oligomerized reaction liquid in the first reactor was then transferred to the second reactor. Next, heating and depressurization of the second reactor were initiated, and the internal temperature reached 240°C and the pressure reached 0.2 kPa in 50 minutes. The polymerization was then allowed to proceed until the specified stirring power was reached. When the predetermined power was reached, nitrogen was introduced into the reactor to restore pressure, and the polyester carbonate resin produced was extruded into water, and the strands were cut to obtain pellets. The obtained polyester carbonate resin (pellets) was vacuum dried at 80°C for 5 hours, and then a long resin film with a thickness of 130 μm was produced using a film-forming device equipped with a single-screw extruder (manufactured by Toshiba Machine Co., Ltd., cylinder set temperature: 250°C), a T-die (width 200 mm, set temperature: 250°C), a chill roll (set temperature: 120-130°C), and a winder. The obtained long resin film was stretched in the width direction at a stretching temperature of 140°C and a stretch ratio of 2.7 times. In this way, a retardation film having a thickness of 47 μm, an Re(590) of 143 nm, and an Nz coefficient (Rth(590) / Re(590)) of 1.2 was obtained. The Re(450) / Re(550) of the obtained retardation film was 0.859. The surface smoothness of the retardation film was 0.25 arcmin.

[0111] [Manufacturing Example 2: Formation of a positive C-plate] A liquid crystal coating solution was prepared by dissolving 20 parts by weight of a side-chain liquid crystal polymer represented by the following chemical formula (1) (the numbers 65 and 35 in the formula indicate the mole percentages of the monomer units, and are conveniently represented as a block polymer: weight-average molecular weight 5000), 80 parts by weight of a polymerizable liquid crystal exhibiting a nematic liquid crystal phase (manufactured by BASF: trade name Paliocolor LC242), and 5 parts by weight of a photopolymerization initiator (manufactured by Ciba Specialty Chemicals: trade name Irgacure 907) in 200 parts by weight of cyclopentanone. [ka]

[0112] The prepared coating solution was applied to a substrate film (norbornene-based resin film, manufactured by Zeon Corporation, trade name "Zeonex") using a bar coater, and then the liquid crystal was aligned by heating and drying at 80°C for 4 minutes. The liquid crystal layer was irradiated with ultraviolet light to harden it, forming a positive C plate (thickness: 0.5 μm to 8 μm, surface smoothness: 0.13 arcmin to 0.23 arcmin) on the substrate film, which had a refractive index characteristic of nz > nx = ny and an Rth(590) in the range of -10 nm to -160 nm. Details of the obtained positive C plate are shown in Table 1. The obtained positive C plate had an Rth(450) / Rth(550) of 1.072, demonstrating positive dispersion wavelength characteristics.

[0113] [Table 1]

[0114] [Production Example 3: Preparation of polarizing film] A long, amorphous isophthalic copolymerized polyethylene terephthalate film (thickness: 100 μm) having a Tg of about 75° C. was used as the thermoplastic resin substrate, and one side of the resin substrate was subjected to a corona treatment. A PVA aqueous solution (coating liquid) was prepared by dissolving 100 parts by weight of a PVA-based resin made by mixing polyvinyl alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetoacetyl-modified PVA (manufactured by Mitsubishi Chemical Corporation, trade name "Gohsenex Z410") in a 9:1 ratio, to which 13 parts by weight of potassium iodide was added, in water. The above PVA aqueous solution was applied to the corona treated surface of the resin substrate and dried at 60° C. to form a PVA resin layer with a thickness of 13 μm, thereby producing a laminate. The resulting laminate was uniaxially stretched 2.4 times in the machine direction (longitudinal direction) in an oven at 130°C (auxiliary in-air stretching treatment). Next, the laminate was immersed in an insolubilizing bath (a boric acid aqueous solution obtained by mixing 4 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 40°C for 30 seconds (insolubilizing treatment). Next, the film was immersed in a dye bath (an aqueous iodine solution obtained by mixing iodine and potassium iodide in a weight ratio of 1:7 with 100 parts by weight of water) at a liquid temperature of 30°C for 60 seconds while adjusting the concentration so that the single transmittance (Ts) of the absorptive polarizing film finally obtained would have the desired value (dyeing treatment). Next, the sample was immersed in a crosslinking bath (a boric acid aqueous solution obtained by blending 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 40°C for 30 seconds (crosslinking treatment). The laminate was then immersed in a boric acid aqueous solution (boric acid concentration 4 wt %, potassium iodide concentration 5 wt %) at a liquid temperature of 70°C and uniaxially stretched in the longitudinal direction (longitudinal direction) between rolls with different peripheral speeds to a total stretch ratio of 5.5 times (underwater stretching treatment). Thereafter, the laminate was immersed in a cleaning bath (aqueous solution obtained by mixing 4 parts by weight of potassium iodide with 100 parts by weight of water) at a liquid temperature of 20°C (cleaning treatment). Thereafter, the laminate was dried in an oven maintained at approximately 90°C and brought into contact with a heated SUS roll whose surface temperature was maintained at approximately 75°C (drying shrinkage treatment). The shrinkage rate in the width direction of the laminate due to the drying shrinkage treatment was 5.2%. In this way, an absorptive polarizing film having a thickness of about 5 μm was formed on the resin substrate. A cycloolefin resin film (thickness: 25 μm) was attached as a protective layer to the surface of the obtained absorptive polarizing film (the surface opposite to the resin substrate) via a UV-curable adhesive. Specifically, the curable adhesive was applied so that the total thickness was approximately 1 μm, and the films were attached using a roller. Thereafter, UV light was irradiated from the cycloolefin resin film side to cure the adhesive. Then, the resin substrate was peeled off. This resulted in a polarizing film having a cycloolefin resin film / absorptive polarizing film structure. The polarizing film had a single transmittance (Ts) of 43.4% and a polarization degree of 99.993%.

[0115] [Production Example 4: Preparation of Optical Laminate A] The positive C plate was attached to the retardation film via a 1 μm-thick adhesive layer, and then the base film was removed from the positive C plate to obtain a laminated portion. The polarizing film was attached to the retardation film side of the resulting laminate via a 5 μm-thick adhesive layer to obtain an optical laminate A. The polarizing film was attached so that the absorption axis of the polarizing film and the slow axis of the retardation film formed an angle of 45°. The polarizing film was also attached so that the absorptive polarizing layer of the polarizing film was positioned on the retardation film side.

[0116] [Production Example 5: Preparation of Optical Laminate B] The positive C plate was attached to the retardation film via a 1 μm-thick adhesive layer, and then the base film was removed from the positive C plate to obtain a laminated portion. The polarizing film was attached to the positive C plate side of the obtained laminate via a 5 μm-thick adhesive layer to obtain an optical laminate B. The polarizing film was attached so that the absorption axis of the polarizing film and the slow axis of the retardation film formed an angle of 45°. The polarizing film was also attached so that the absorptive polarizing film was positioned on the positive C plate side.

[0117] [Production Example 6: Preparation of optical laminate C] The positive C plate was attached to the retardation film via a 1 μm-thick adhesive layer, and then the base film was removed from the positive C plate to obtain a laminated portion. On the positive C-plate side of the obtained laminate, a TAC film 1 (thickness 25 μm, manufactured by Fujifilm Corporation, "TJ25UL") with an Rth(590) of 14 nm or a TAC film 2 (thickness 80 μm, manufactured by Konica Minolta, "KC8UY") with an Rth(590) of 50 nm was bonded via a 5 μm thick adhesive layer as a negative C-plate having a refractive index characteristic of nx = ny > nz. Next, the polarizing film was bonded to the surface of the negative C-plate via a 5 μm thick adhesive layer to obtain an optical laminate C. At this time, the polarizing film was bonded so that the absorption axis and the slow axis of the retardation film formed an angle of 45°. In addition, the polarizing film was bonded so that the absorptive polarizing film was located on the negative C-plate side.

[0118] <Evaluation> The two laminates obtained in the above Production Example were arranged one above the other with their polarizing films positioned on the outside, as shown in Table 2. When the absorption axis of the polarizing film of the upper laminate was taken as the reference (0°), the slow axis of the retardation film of the upper laminate formed an angle of 45° with respect to this reference, the absorption axis of the polarizing film of the lower laminate formed an angle of 90°, and the slow axis of the retardation film of the lower laminate formed an angle of 135°. In addition, since both the absorptive polarizing element and the reflective polarizing element can have the function of transmitting linearly polarized light but not transmitting linearly polarized light perpendicular to this linearly polarized light, for convenience in the evaluation, an absorptive polarizing element is also used as the polarizing element contained in the upper laminate.

[0119] [Table 2]

[0120] A backlight was turned on from the lower surface side of the lower laminate, and the luminance of the light emitted from the upper laminate was measured using a conoscope (manufactured by AUTRONIC MELCHRS). As a backlight, a UV-LED irradiator was used, which was dimmed using a UV constant current control power supply (LPDC series manufactured by ITEC Systems, adjustment parameters: COARSE2 / FINE8). The incident and outgoing angles are polar angles of 30°, and the luminance (cd / m 2 ) was measured and the average value was calculated. For each configuration shown in Table 2, the Rth(590) of the positive C-plate was changed and the measurement results (average luminance, unit: cd / m 2 ) are summarized in Table 3. From the viewpoint of manufacturing efficiency, the Rth(590) of the positive C-plates included in the upper and lower laminates was set to be substantially the same (Rth(550): -10 nm to -160 nm). The results were the same for Configuration 1 and Configuration 2, and the results were the same for Configuration 3 and Configuration 4. The evaluation results for configurations 3 and 4 in Table 3 are shown separately for the optical laminate C when the above TAC film 1 was used ("TAC1" in Table 3) and when the above TAC film 2 was used ("TAC2" in Table 3).

[0121] [Table 3]

[0122] In the configurations 1 and 2 shown in Table 2, when the Rth(590) of the positive C-plate is -110 nm, the luminance is 52.0 cd / m 2 In contrast, in the configuration of Comparative Example 1, when the Rth(590) of the positive C-plate is −80 nm, the luminance is 60.2 cd / m 2 In the configurations 1 and 2 shown in Table 2, lower brightness can be achieved by adjusting the retardation in the thickness direction of the positive C-plate. Furthermore, lower brightness can be achieved by combining a negative C-plate.

[0123] In FIG. 4, the measurement results shown in Table 3 are plotted.

[0124] The present invention is not limited to the above-described embodiment, and various modifications are possible. For example, the configurations shown in the above-described embodiment can be replaced with configurations that are substantially the same as those shown in the above-described embodiment, that have the same effects, or that can achieve the same purpose. [Industrial Applicability]

[0125] A display system according to an embodiment of the present invention can be used in a display such as VR goggles, for example. [Explanation of symbols]

[0126] 2. Display System 12 Display element 14 Reflector 16 First lens part 18 Half Mirror 20 First phase difference member 22 Second phase difference member 24 Second lens section 30 First member 30a Positive C Plate 30b Negative C Plate 32 Second member 32a Positive C Plate 32b Negative C Plate 100 First optical laminate 200 Second optical stack

Claims

1. 1. A display system for displaying an image to a user, comprising: a display element having a display surface that emits light representing an image forward via a polarizing member; a reflecting section disposed in front of the display element, the reflecting section including a reflective polarizing member, and the reflecting section reflecting light emitted from the display element; a first lens portion disposed on an optical path between the display element and the reflector; a half mirror disposed between the display element and the first lens portion, the half mirror transmitting light emitted from the display element and reflecting light reflected by the reflecting portion toward the reflecting portion; a first phase difference member disposed on an optical path between the display element and the half mirror; a first member disposed on an optical path between the display element and the half mirror; a second phase difference member disposed on an optical path between the half mirror and the reflecting portion; a second member disposed on an optical path between the half mirror and the reflecting portion, the first phase difference member and the second phase difference member are phase difference members capable of converting linearly polarized light into circularly polarized light or circularly polarized light into linearly polarized light, the first member and the second member each provide a phase difference in a thickness direction and include a positive C plate; a member that imparts a phase difference in the thickness direction is located in front of or behind the phase difference member both between the display element and the half mirror and between the half mirror and the reflecting portion, the first member or the second member further includes a negative C plate; Display system.

2. 2. The display system according to claim 1, wherein, both between the display element and the half mirror and between the half mirror and the reflecting portion, the member that imparts a phase difference in the thickness direction is located forward of the phase difference member, and the second member includes a negative C plate.

3. 2. The display system according to claim 1, wherein, both between the display element and the half mirror and between the half mirror and the reflecting portion, the member that provides a phase difference in the thickness direction is located behind the phase difference member, and the first member includes a negative C plate.

4. The display system according to claim 3 , wherein the negative C plate included in the first member functions as a protective layer for an absorptive polarizing film included in the polarizing member.

5. The display system according to claim 4 , wherein the negative C plate included in the first member is made of a cellulose-based resin.

6. 2. The display system according to claim 1, wherein the positive C plates included in the first phase difference member, the second phase difference member, the first member, and the second member each have a surface smoothness of 1.0 arcmin or less.

7. The display system according to claim 1, wherein a first optical stack including the polarizing member, the first phase difference member, and the first member, and a second optical stack including the reflective section, the second phase difference member, and the second member each have an ellipticity of 0.77 or more for transmitted light at a wavelength of 550 nm measured at a polar angle of 30° and an azimuth angle of 0° to 360°.

8. 2. The display system of claim 1, wherein a first optical stack including the polarizing element, the first phase difference element, and the first element, and a second optical stack including the reflecting portion, the second phase difference element, and the second element each have an ellipticity of 0.94 or more for transmitted light at a wavelength of 550 nm measured at a polar angle of 0°.

9. The display system of claim 1, wherein the first optical stack including the polarizing element, the first phase difference element, and the first element, and the second optical stack including the reflective portion, the second phase difference element, and the second element each have a depolarization index (DI) of 1 minus DI of transmitted light having a wavelength of 550 nm measured at a polar angle of 0° (1-DI) of 95.5% or more.

10. The display system of claim 1 , further comprising a second lens portion disposed in front of the reflector portion.

11. A display comprising a display system according to any one of claims 1 to 10.

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