Display system and display body

Abstract

A display system (2) according to the present invention comprises: a display element (12) that emits light representing an image forward via a polarization member; a reflection part (14) that is disposed in front of the display element (12), includes a reflection-type polarization member, and reflects the light emitted from the display element (12); a first lens part (16) that is disposed between the display element (12) and the reflection part (14); a half mirror (18) that is disposed between the display element (12) and the first lens part (16), transmits the light emitted from the display element (12), and reflects the light reflected by the reflection part (14) toward the reflection part (14); a first phase difference member (20) and a first member that are disposed between the display element (12) and the half mirror (18); and a second phase difference member (22) and a second member that are disposed between the half mirror (18) and the reflection part (14). The first phase difference member (20) and the second phase difference member (22) are each a phase difference member capable of converting linearly polarized light into circularly polarized light or converting circularly polarized light into linearly polarized light. The first member and the second member are each a member for giving a phase difference in a thickness direction. The member for giving the phase difference in the thickness direction, whether located between the display element (12) and the half mirror (18) or between the half mirror (18) and the reflection part (14), is located in front of or behind the phase difference member (20, 22).

Description

Display system and display body

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

[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 image display performance (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. Because VR goggles are being considered for use in a variety of situations, there is a demand for them to be lightweight, high-definition, and the like. 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.

[0004] Japanese Patent Application Laid-Open No. 2021-103286

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

[0006] 1. A display system according to an embodiment of the present invention is 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 and including a reflective polarizing member, and that reflects the light emitted from the display element; a first lens section disposed on an optical path between the display element and the reflecting section; a half mirror disposed between the display element and the first lens section, that 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 disposed on an optical path between the display element and the half mirror; a first member arranged on an optical path between the display element and the half mirror, a second phase difference member arranged on an optical path between the half mirror and the reflecting unit, and a second member arranged on an optical path between the half mirror and the reflecting unit, wherein the first phase difference member and the second phase difference member are each phase difference members capable of converting linearly polarized light into circularly polarized light or circularly polarized light into linearly polarized light, and the first member and the second member are each members that impart a phase difference in a thickness direction, and both between the display element and the half mirror and between the half mirror and the reflecting unit, the member that imparts the phase difference in the thickness direction is located in front of or behind the phase difference member. 2. In the display system described in 1 above, the member that imparts the phase difference in the thickness direction may be a positive C plate. 3. In the display system described in 1 or 2 above, 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. 4. In the display system described in any one of 1 to 3 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 reflective section, the second phase difference member, and the second member may each have an ellipticity of 0.77 or more for transmitted light of a wavelength of 550 nm measured at a polar angle of 30° and an azimuth angle of 0° to 360°.5. In the display system described in any one of 1 to 4 above, the first optical stack including the polarizing member, the first retardation member, and the first member, and the second optical stack including the reflecting section, the second retardation member, and the second member 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°. 6. In the display system described in any one of 1 to 5 above, the first optical stack including the polarizing member, the first retardation member, and the first member, and the second optical stack including the reflecting section, the second retardation member, and the second member 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. 7. In the display system described in any one of 1 to 6 above, the first member and the second member may be positive C plates having substantially the same thickness direction retardation Rth(590). 8. In the display system described in 7, the thickness direction retardation Rth(590) is x (unit: nm), and a backlight is turned on from the first optical laminate side to allow light to be incident on a first optical laminate including the polarizing member, the first retardation member, and the first member, and a second optical laminate including the reflective section, the second retardation member, and the second member, and the light is emitted from the second optical laminate, the incident angle and the exit angle are set to a polar angle of 30°, and the luminance is measured at azimuth angles of 5° in a range of azimuth angles from 0° to 355°, and the average value of the obtained values ​​is y (unit: cd / m). ２ ) and y = ax ２ When approximated by +bx+c, a may be 0.030 or less. 9. The display system according to any one of 1 to 8 above may include a second lens unit disposed in front of the reflecting unit. 10. A display according to an embodiment of the present invention includes the display system according to any one of 1 to 9 above.

[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.

[0008] It is a schematic diagram showing the general configuration of a display system according to one embodiment of the present invention. It is a diagram showing an example of the positional relationship of members arranged between a display element and a reflector of the display system shown in Fig. 1. It is a diagram showing another example of the positional relationship of members arranged between a display element and a reflector of the display system shown in Fig. 1. It is a diagram showing the brightness in the arrangement of laminates of Examples and Comparative Examples.

[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 maximum (i.e., the slow axis direction), "ny" is the refractive index in the in-plane direction perpendicular to the slow axis (i.e., the fast axis direction), and "nz" is the refractive index in the thickness direction. (2) In-Plane Retardation (Re) "Re(λ)" is the in-plane retardation measured with light having a wavelength of λ nm at 23°C. For example, "Re(550)" is the in-plane retardation measured with light having a wavelength of 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) Thickness Direction Retardation (Rth) "Rth(λ)" is the retardation in the thickness direction measured with light having a wavelength of λ nm at 23°C. For example, "Rth(550)" is the retardation in the thickness direction measured with light having a wavelength of 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 an angle is referred to in this specification, unless otherwise specified, the angle includes both clockwise and counterclockwise angles with respect to the reference direction. Therefore, for example, "45°" means ±45°. Furthermore, in this specification, "substantially parallel" includes the range of 0° ±10°, preferably within the range of 0° ±5°, more preferably within the range of 0° ±3°, and even more preferably within the range of 0° ±1°. "Approximately perpendicular" encompasses the range of 90°±10°, preferably within the range of 90°±5°, more preferably within the range of 90°±3°, and even more preferably within the 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 phase difference member 20, a second phase difference 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 phase difference member 20 is disposed on the optical path between the display element 12 and the half mirror 18, and the second phase difference 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 12 a for displaying an image. The light emitted from the display surface 12 a 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 the 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 unit 14 toward the reflecting unit 14. In the example shown in FIG. 1 , the half mirror 18 is provided integrally with the first lens unit 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 user's eye 26 .

[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 (e.g., light leakage in an oblique direction) can be prevented. This can also reduce 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 phase difference member 20 and a first member 30 that imparts a thickness direction phase difference 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 phase difference and a second phase difference 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 phase difference are arranged in front of the phase difference members 20 and 22, respectively. The polarizing member 10, the first phase difference 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 phase difference 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 phase difference member 22.

[0023] In the example shown in FIG. 3 , a first member 30 that imparts a thickness direction phase difference 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 phase difference are arranged in this order behind the reflecting portion 14 (on the left side of FIG. 2 ). The members 30 and 32 that impart a thickness direction phase difference are arranged behind the phase difference 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 portion 14, the second phase difference member 22, and the second member 32 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. 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 the optical stack), the components constituting the optical stack can be laminated via any appropriate adhesive layer. By laminating the components via an adhesive layer, an optical stack with excellent smoothness can be obtained. In the above display system, the image can be enlarged in the lens portion (for example, by a convex lens), and the smoothness of the optical stack can greatly 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 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 may be 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 according to 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. It is preferable that the λ / 4 member 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 even more preferably satisfies all of them.

[0032] The λ / 4 member preferably has a refractive index characteristic that satisfies the relationship nx>ny≧nz. Here, "ny=nz" includes not only the case where ny and nz are completely equal, but also the case where they are substantially equal. Therefore, there may be cases where ny<nz, as long as the effects of the present invention are not impaired. 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, even more preferably 0.4 to 1.5, and particularly preferably 0.4 to 1.3.

[0033] The λ / 4 member is formed of any appropriate material that can satisfy the above characteristics. The λ / 4 member may be, for example, a stretched resin film or an oriented and solidified layer of a liquid crystal compound. Note that a stretched resin film may also 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] As the polycarbonate-based resin, any suitable polycarbonate-based resin can be used as long as the effects of the present invention can be obtained. 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 that can be suitably used for λ / 4 members and methods for forming λ / 4 members are described in, for example, 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 curing 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 a 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 formed of the 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 formed of the 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, sometimes simply referred to as a layer included in the laminate structure) preferably exhibits an inverse dispersion wavelength characteristic in which the retardation value increases according to the wavelength of the measurement light. The Re(450) / Re(550) of the layer included in the laminate structure may be, for example, 0.75 or more and less than 1, or 0.8 or more and 0.95 or less.

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

[0048] The layers included in the laminate structure preferably have refractive index characteristics that satisfy the relationship nx>ny≧nz. Here, "ny=nz" includes not only the case where ny and nz are completely equal, but also the case where they are substantially equal. Therefore, there may be cases where ny<nz, as long as the effects of the present invention are not impaired. The Nz coefficient (Rth(550) / Re(550)) of the layers included in the laminate structure is preferably 0.4 to 3, more preferably 0.4 to 2.5, even more preferably 0.4 to 1.5, and particularly preferably 0.4 to 1.3.

[0049] The layers included in the laminate structure are formed of any appropriate material that can satisfy the above characteristics. The layers included in the laminate structure can be, for example, a stretched resin film or an oriented and solidified layer of a liquid crystal compound. Details of the stretched resin film and the oriented and solidified layer of a liquid crystal compound are as described above. When the layers included in the laminate structure have flat wavelength dispersion characteristics, preferred examples of the materials for forming them include cycloolefin resins, and in particular norbornene resins.

[0050] Norbornene-based resins are resins polymerized using norbornene-based monomers as polymerization units. Examples of norbornene-based 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 member 30 and the second member 32 that impart a phase difference in the thickness direction (hereinafter, sometimes simply referred to as a member that imparts a phase difference in the thickness direction) can be typically a member whose refractive index characteristics can exhibit the relationship nz > nx = ny (a so-called positive C plate).

[0057] The thickness direction retardation Rth(590) of the positive C plate is preferably −20 nm to −200 nm, more preferably −30 nm to −180 nm, even more preferably −40 nm to −160 nm, and particularly preferably −50 nm to −140 nm. Here, "nx=ny" includes not only the case where nx and ny are strictly equal, but also the case where nx and ny are substantially equal. The in-plane retardation Re(550) of the positive C plate is, for example, less than 10 nm.

[0058] The positive C plate may be made of any suitable material that satisfies the above-mentioned characteristics, and may be, for example, a resin film or an oriented and solidified layer of a liquid crystal compound.

[0059] 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 in which chemical bonds or functional groups with large polarization anisotropy, such as aromatic rings or carbonyl groups, are introduced into the side chain. Specific examples of resins having negative birefringence include acrylic resins, styrene resins, maleimide resins, modified polyolefin resins, fumaric acid ester resins, etc., and specific examples thereof can be found in JP 2021-076759 A, JP 2008-544304 A, JP 2008-544317 A, etc., for example. The above resin materials can be used alone or in combination of two or more.

[0060] 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 the additives may be appropriately determined depending on the purpose. The content of the additives in the resin film is, for example, about 3% to 10% by weight.

[0061] 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 with high birefringence expression and negative intrinsic birefringence is used, a coating film with large thickness-direction birefringence can be formed on the support due to shrinkage during drying. The formed coating film can then be used as a positive C plate as is.

[0062] 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.

[0063] A preferred example of the alignment and solidification layer of a liquid crystal compound constituting the positive C plate is an alignment and solidification 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 paragraphs

[0020] to

[0028] of JP-A-2002-333642.

[0064] 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.

[0065] The first member 30 and the second member 32 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 member 30 and the second member 32 may have the same configuration.

[0066] The surface smoothness of the retardation member and the member imparting retardation in the thickness direction 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 such a 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.

[0067] The thickness variation of the retardation member and the member imparting retardation in the thickness direction 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 position spaced 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.

[0068] 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.

[0069] 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 may be 10 μm or less, or may be 8 μm or less, or may be 5 μm or less.

[0070] 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.

[0071] When the absorptive polarizing film is produced from a single-layer resin film, for example, an absorptive polarizing film can be obtained by subjecting a hydrophilic polymer film such as a polyvinyl alcohol (PVA)-based film, a partially formalized PVA-based film, or a partially saponified ethylene-vinyl acetate copolymer-based film to a dyeing treatment with iodine or a dichroic substance such as a dichroic dye, a stretching treatment, etc. Among these, an absorptive polarizing film obtained by dyeing a PVA-based film with iodine and uniaxially stretching it is preferred.

[0072] The dyeing with iodine is carried out, for example, by immersing the PVA-based 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 PVA-based film may be dyed after stretching. If necessary, the PVA-based film may be subjected to a swelling treatment, a crosslinking treatment, a washing treatment, a drying treatment, or the like.

[0073] 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, and 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 solution 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 to stretch it. Furthermore, the stretching may optionally include in-air stretching of the laminate at a high temperature (e.g., 95°C or higher) before stretching in the boric acid aqueous solution. In addition, in this embodiment, the laminate is preferably subjected to a drying shrinkage treatment in which the laminate is heated 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 auxiliary in-air 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 the PVA, even when the PVA is coated on a thermoplastic resin substrate, thereby achieving high optical properties. Furthermore, by simultaneously increasing the orientation of the PVA in advance, problems such as a decrease in orientation or dissolution of the PVA when immersed in water in the subsequent dyeing or 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 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 the absorptive polarizing film obtained through treatment steps in which the laminate is immersed in a liquid, such as a dyeing treatment and an underwater stretching treatment.Furthermore, the optical properties can be improved by shrinking the laminate in the width direction through a 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 an absorptive polarizing film are described in, for example, JP-A-2012-73580 and Japanese Patent No. 6,470,455. The entire disclosures of these publications are incorporated herein by reference.

[0074] The crossed transmittance (Tc) of the absorptive polarizing film (absorptive polarizing element) 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 element) 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 element) is, for example, 99.0% to 99.997%, and preferably 99.9% or more.

[0075] The reflective polarizing element included in the reflecting section 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 composed of a film having a multilayer structure (sometimes referred to as a reflective polarizing film). 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.

[0076] Commercially available reflective polarizing films include, for example, "DBEF" and "APF" manufactured by 3M, and "APCF" manufactured by Nitto Denko Corporation.

[0077] The crossed transmittance (Tc) of the reflective polarizing element (reflective polarizing film) can be, for example, 0.01% to 3%. The single transmittance (Ts) of the reflective polarizing element (reflective polarizing film) can be, for example, 43% to 49%, preferably 45% to 47%. The polarization degree (P) of the reflective polarizing element (reflective polarizing film) can be, for example, 92% to 99.99%.

[0078] 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.

[0079] 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 an upper limit of 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 completely circularly polarized light is 1, and the ellipticity of completely linearly polarized light is 0.

[0080] 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 the emitted light 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 obtained measurements is X.

[0081] 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).

[0082] 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 (for example, 550 nm) from the polarizing member side of the optical laminate.

[0083] 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 from the following formula (2) by measuring a Mueller matrix (the following (1)) that represents the polarization effect. The Mueller matrix that represents the polarization effect 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 (for example, 550 nm) from the polarizing member side of the optical laminate.

[0084] The optical laminate preferably has a value (1-DI) obtained by subtracting the depolarization index (DI) of transmitted light having a wavelength of 550 nm measured at a polar angle of 30° and an azimuth angle of 0° to 360° from 1. 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 the 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°. The optical laminate preferably has a value (1-DI) obtained by subtracting the depolarization index (DI) of transmitted light having a wavelength of 550 nm measured at a polar angle of 0° (front direction) from 1. The value (1-DI) obtained by subtracting the depolarization index (DI) of transmitted light having a wavelength of 550 nm measured at a polar angle of 0° (front direction) from 1 is preferably 99.5% or more, and more preferably 99.75% or more.

[0085] 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.

[0086] (1) Thickness: Thicknesses of 10 μm or less were measured using a scanning electron microscope (manufactured by JEOL Ltd., product name "JSM-7100F"). Thicknesses exceeding 10 μm were measured using a digital micrometer (manufactured by Anritsu Corporation, product name "KC-351C"). (2) Retardation Value: Retardation values ​​at a predetermined wavelength were 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 Degree of Polarization of Polarizing Film: The single transmittance Ts, parallel transmittance Tp, and crossed transmittance Tc of the polarizing film were measured using a spectrophotometer (manufactured by Otsuka Electronics Co., Ltd., "LPF-200"). These Ts, Tp, and Tc values ​​are Y values ​​measured using a 2-degree visual field (C light source) according to JIS Z8701 and corrected for luminous efficiency. The degree of polarization 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 The surface smoothness was measured using a phase-shifting laser interferometer (manufactured by Zygo, product name "DynaFiz"). Specifically, the measurement object was laminated on a microslide glass (manufactured by Matsunami Glass Industry Co., Ltd., product name "S200200") to prevent the intrusion of foreign matter, bubbles, and deformation lines. Next, to remove the influence of minute bubbles, degassing was performed using a pressure degassing device (autoclave). The degassing conditions were 50 ° C, 0.5 MPa, and 30 minutes. After degassing, the sample was allowed to cool at room temperature for 30 minutes or more to obtain a measurement sample. The measurement sample was placed on a measurement table with a vibration-isolating table, and a single-wavelength (633 nm) laser was used to interfere with a standard with guaranteed flatness, and the relative displacement within a predetermined area (a circle of 30 mm φ) was measured. For the analysis, the surface smoothness (unit: arcmin) was defined as double the value (equivalent to 2σ) of the angle index "Slope magnitude RMS" obtained by extracting frequency values ​​from 0.1 / mm to 1 / mm.

[0087] [Production Example 1: Production of Retardation Film] A batch polymerization apparatus consisting of two vertical reactors equipped with stirring blades and reflux condensers controlled to 100°C was charged with 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. －２ Part by weight (6.78 x 10 －５mol) was charged. After purging the reactor with nitrogen under reduced pressure, heating was performed with a heat medium, and stirring was initiated when the internal temperature reached 100°C. 40 minutes after the start of the temperature increase, the internal temperature reached 220°C, and while controlling to maintain this temperature, pressure reduction was initiated. 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 a small amount of monomer components contained in the phenol vapor were returned to the reactor, while uncondensed phenol vapor was introduced into a condenser at 45°C and recovered. Nitrogen was introduced into the first reactor, and the pressure was temporarily restored to atmospheric pressure. The oligomerized reaction liquid in the first reactor was then transferred to the second reactor. Next, heating and pressure reduction in the second reactor were initiated, and the internal temperature reached 240°C and the pressure reached 0.2 kPa in 50 minutes. Polymerization was then allowed to proceed until the predetermined stirring power was achieved. When the predetermined power was reached, nitrogen was introduced into the reactor to restore the pressure, and the resulting polyester carbonate resin was extruded into water and cut into strands to obtain pellets. The resulting polyester carbonate resin (pellets) was vacuum-dried at 80 ° C for 5 hours, and then a film-forming device equipped with a single-screw extruder (manufactured by Toshiba Machine Co., Ltd., cylinder setting temperature: 250 ° C), a T-die (width 200 mm, setting temperature: 250 ° C), a chill roll (setting temperature: 120-130 ° C) and a winder was used to produce a long resin film with a thickness of 130 μm. 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 obtained retardation film had an Re(450) / Re(550) of 0.859 and a surface smoothness of 0.25 arcmin.

[0088] [Production Example 2: Formation of 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) (in the formula, the numbers 65 and 35 indicate the mol % of the monomer unit, and for convenience, it is expressed 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.

[0089] 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: 3 μm to 6.5 μm, surface smoothness: 0.15 arcmin to 0.18 arcmin) on the substrate film, which had a refractive index characteristic of nz > nx = ny and an Rth(590) in the range of -60 nm to -130 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 and exhibited positive dispersion wavelength characteristics.

[0090]

[0091] [Production Example 3: Preparation of Polarized Film] A long, amorphous, isophthalic acid-copolymerized polyethylene terephthalate film (thickness: 100 μm) with a Tg of approximately 75°C was used as the thermoplastic resin substrate. One side of the resin substrate was subjected to a corona treatment. A PVA-based resin (100 parts by weight of a 9:1 mixture of polyvinyl alcohol (degree of polymerization: 4200, degree of saponification: 99.2 mol%) and acetoacetyl-modified PVA (manufactured by Mitsubishi Chemical Corporation, product name "GOHSENEX Z410") was dissolved in water with 13 parts by weight of potassium iodide to prepare an aqueous PVA solution (coating solution). The PVA aqueous solution was applied to the corona-treated surface of the resin substrate and dried at 60°C to form a 13 μm-thick PVA-based resin layer, producing a laminate. The resulting laminate was uniaxially stretched 2.4 times in the longitudinal direction (longitudinal direction) in an oven at 130°C (in-air auxiliary stretching treatment). Next, the laminate was immersed for 30 seconds in an insolubilizing bath (a boric acid aqueous solution obtained by blending 4 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 40°C (insolubilization treatment). Next, the laminate was immersed for 60 seconds in a dyeing bath (an iodine aqueous solution obtained by blending 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 while adjusting the concentration so that the single-unit transmittance (Ts) of the finally obtained absorptive polarizing film would have a desired value (dyeing treatment). Next, the laminate was immersed for 30 seconds 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 (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 (machine direction) between rolls operating at different peripheral speeds to a total stretch ratio of 5.5 (underwater stretching treatment). The laminate was then immersed in a cleaning bath (an aqueous solution obtained by blending 4 parts by weight of potassium iodide with 100 parts by weight of water) at a liquid temperature of 20°C (washing treatment). The laminate was then brought into contact with a SUS heated roll whose surface temperature was maintained at approximately 75°C while being dried in an oven maintained at approximately 90°C (drying shrinkage treatment). The shrinkage rate of the laminate in the width direction due to the drying shrinkage treatment was 5.2%. In this manner, an absorptive polarizing film having a thickness of approximately 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. The adhesive was then cured by irradiating it with UV light from the cycloolefin resin film side. The resin substrate was then peeled off. This resulted in a polarizing film having a cycloolefin resin film / absorptive polarizing film configuration. The polarizing film had a single transmittance (Ts) of 43.4% and a polarization degree of 99.993%.

[0092] [Production Example 4: Preparation of Optical Laminate A] The positive C plate was bonded to the retardation film via a 1 μm-thick adhesive layer, and then the substrate film was removed from the positive C plate to obtain a laminate. The polarizing film was bonded to the retardation film side of the obtained laminate via a 5 μm-thick adhesive layer to obtain an optical laminate A. 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 retardation film side.

[0093] [Production Example 5: Preparation of Optical Laminate B] The positive C plate was bonded to the retardation film via a 1 μm-thick adhesive layer, and then the substrate film was removed from the positive C plate to obtain a laminate. The polarizing film was bonded to the positive C plate side of the obtained laminate via a 5 μm-thick adhesive layer to obtain an optical laminate B. At this time, the polarizing film was bonded so that the absorption axis of the polarizing film 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 positive C plate side.

[0094] <Evaluation> As shown in Table 2, the two laminates obtained in the above production examples were arranged one above the other with the polarizing films positioned on the outside of each other. 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 was arranged at a 45° angle, the absorption axis of the polarizing film of the lower laminate was arranged at a 90° angle, and the slow axis of the retardation film of the lower laminate was arranged at a 135° angle relative to this reference. Note that 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 the linearly polarized light, and therefore, for convenience in the evaluation, an absorptive polarizing element was also used as the polarizing element included in the upper laminate.

[0095]

[0096] A backlight was turned on from the underside of the lower laminate, and the luminance of the light emitted from the upper laminate was measured using a conoscope (manufactured by AUTRONIC MELCHRS). A UV-LED irradiator was used as the backlight, and its brightness was adjusted using a UV constant current control power supply (LPDC series manufactured by ITEC Systems, adjustment parameters: COARSE2 / FINE8). The incident and exit angles were set to a polar angle of 30°, and the luminance (cd / m) was measured at intervals of 5° in the azimuth angle range of 0° to 355°. 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 production efficiency, the Rth(590) of the positive C plates included in the upper and lower laminates was set to be substantially the same.

[0097]

[0098] In FIG. 4, the measurement results of Examples (Examples 1 and 2) and Comparative Example 1 when the Rth(590) of the positive C plate was changed are plotted, and a quadratic curve (y=ax ２ + bx + c).

[0099] In an embodiment, lower luminance can be achieved by adjusting the Rth(590) of the positive C-plate. For example, a fitted quadratic curve (y=ax ２ +bx+c) is preferably 0.030 or less.

[0100] 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.

[0101] A display system according to an embodiment of the present invention can be used in a display such as VR goggles, for example.

[0102] 2 Display system 12 Display element 14 Reflection section 16 First lens section 18 Half mirror 20 First phase difference member 22 Second phase difference member 24 Second lens section 30 First member 32 Second member 100 First optical laminate 200 Second optical laminate

Claims

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 element; a reflecting section that is arranged in front of the display element, includes a reflective polarizing element, 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, 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; a first member that is arranged on the optical path between the display element and the half mirror; a second phase difference member that is arranged on the optical path between the half mirror and the reflecting section; and a second member that is arranged on the optical path between the half mirror and the reflecting section, wherein the first phase difference member and the second phase difference member are phase difference members that can convert linearly polarized light into circularly polarized light or circularly polarized light into linearly polarized light, a display system in which the first member and the second member are members that impart a phase difference in a thickness direction, and both between the display element and the half mirror and between the half mirror and the reflecting portion, the members that impart the phase difference in the thickness direction are located in front of or behind the phase difference members.

2. The display system according to claim 1, wherein the member that imparts a phase difference in the thickness direction is a positive C plate.

3. The display system according to claim 1, wherein 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.

4. The display system according to claim 1, wherein the first optical laminate including the polarizing member, the first phase difference member, and the first member, and the second optical laminate 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°.

5. 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 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°.

6. 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 reflecting portion, the second phase difference element, and the second element, each have a depolarization index (DI) of 1 minus DI for transmitted light with a wavelength of 550 nm measured at a polar angle of 0° (1-DI) of 95.5% or more.

7. The display system according to claim 1, wherein the first member and the second member are positive C plates having substantially the same retardation Rth(590) in the thickness direction.

8. The retardation Rth(590) in the thickness direction is defined as x (unit: nm), and a backlight is turned on from the first optical laminate side to allow light to be incident on a first optical laminate including the polarizing member, the first retardation member, and the first member, and a second optical laminate including the reflective section, the second retardation member, and the second member, and the light is emitted from the second optical laminate, and the incident angle and the exit angle are set to a polar angle of 30°, and the luminance is measured at azimuth angles of 5° in the range of azimuth angles from 0° to 355°, and the average value of the obtained values ​​is defined as y (unit: cd / m ２ ) and y = ax ２ The display system according to claim 7 , wherein a is 0.030 or less when approximated by +bx+c.

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

10. A display comprising a display system according to any one of claims 1 to 9.

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