Optical laminate and display system

Abstract

To provide an optical laminate capable of favorably achieving weight saving of a VR goggle while improving visibility.SOLUTION: An optical laminate includes: a retardation member having a first principal plane and a second principal plane facing each other, and configured to convert linear polarized light incident from a side of the first principal plane into circular polarized light and emit from a side of the second principal plane; and a protective member having a slow axis and arranged on a side of the second principal plane of the retardation member. The slow axis of the protective member and a polarization direction of the linear polarized light form an angle of 15° or less, or 75° to 105°.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an optical stack and a display system. [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 retardation components and polarizing components are generally used to realize image display and improve image display performance (see, for example, Patent Document 1). These optical components can be integrated in advance and mounted on the image display device as an optical laminate.

[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 improved visibility. [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] The weight reduction of the VR goggles can be achieved, for example, by thinning the lenses used in the VR goggles. On the other hand, there is also a need for the development of an optical laminate including the optical member suitable for a display system using lenses.

[0006] In view of the above, a main object of the present invention is to provide an optical laminate that can effectively achieve weight reduction of VR goggles while improving visibility. [Means for solving the problem]

[0007] [1] According to one aspect of the present invention, there is provided an optical laminate comprising: a retardation element having a first principal surface and a second principal surface opposed to each other, which converts linearly polarized light incident on the first principal surface side into circularly polarized light and emits the circularly polarized light from the second principal surface side; and a protective element having a slow axis and disposed on the second principal surface side of the retardation element, wherein the angle formed between the slow axis of the protective element and the polarization direction of the linearly polarized light is 15° or less or 75° to 105°. [2] In the optical laminate described in [1] above, the retardation member may include a λ / 4 layer having an Re(550) of 100 nm to 190 nm, and the angle formed between the slow axis of the protective member and the slow axis of the λ / 4 layer may be 30° to 60°. [3] The optical laminate according to [1] or [2] above may further include a polarizing element arranged on the first main surface side of the retardation element, and the angle formed between the slow axis of the protective element and the polarization axis of the polarizing element may be 15° or less or 75° to 105°. [4] In the optical laminate according to any one of [1] to [3] above, the difference between the ellipticity of the circularly polarized light having a wavelength of 550 nm that is emitted from the second main surface side of the phase difference member and the ellipticity of the circularly polarized light having a wavelength of 550 nm that is transmitted through the protective member and emitted may be 0.02 or less. [5] The optical laminate according to any one of [1] to [4] above may satisfy at least one of the following (i) and (ii): (i) a difference between the ellipticity of light with a wavelength of 450 nm in the circularly polarized light emitted from the second main surface side of the retardation member and the ellipticity of light with a wavelength of 450 nm in the circularly polarized light that is transmitted through the protective member and emitted is 0.02 or less; (ii) The difference between the ellipticity of the 650 nm wavelength light in the circularly polarized light emitted from the second main surface side of the phase difference member and the ellipticity of the 650 nm wavelength light in the circularly polarized light that is transmitted through the protective member and emitted is 0.02 or less. [6] In the optical laminate according to any one of [1] to [5] above, the protective member may include a substrate, and the substrate may include at least one resin selected from an acrylic resin and a triacetyl cellulose resin. [7] In the optical laminate according to [6] above, the protective member may further include an antireflection layer disposed on the side of the substrate opposite to the side on which the retardation member is disposed. [8] In the optical laminate according to any one of [1] to [7] above, the protective member may have an Re(550) of 0.5 nm or more. [9] In the optical laminate according to any one of [1] to [8] above, the retardation member and the protective member may be laminated via a pressure-sensitive adhesive layer.

[10] The optical laminate according to any one of [1] to [9] above may be used in a display system including: a display element having a display surface that emits light representing an image forward via a polarizing element; a reflective polarizing element disposed in front of the display element and reflecting the light emitted from the display element; a first lens portion disposed on an optical path between the display element and the reflective polarizing element; a half mirror disposed between the display element and the first lens portion that transmits the light emitted from the display element and reflects the light reflected by the reflective polarizing element toward the reflective polarizing element; a first phase difference element disposed on the optical path between the display element and the half mirror and capable of converting linearly polarized light into circularly polarized light or circularly polarized light into linearly polarized light; and a second phase difference element disposed on the optical path between the half mirror and the reflective polarizing element and capable of converting linearly polarized light into circularly polarized light or circularly polarized light into linearly polarized light, wherein the phase difference element may be disposed to function as the first phase difference element or the second phase difference element.

[11] According to another aspect of the present invention, there is provided a display system comprising: a display element having a display surface that emits light representing an image forward via a polarizing element; a reflective polarizing element that is arranged in front of the display element and reflects the light emitted from the display element; a first lens unit that is arranged on an optical path between the display element and the reflective polarizing element; a half mirror that is arranged between the display element and the first lens unit and transmits the light emitted from the display element and reflects the light reflected by the reflective polarizing element toward the reflective polarizing element; a first phase difference element that is arranged on the optical path between the display element and the half mirror and is capable of converting linearly polarized light into circularly polarized light or circularly polarized light into linearly polarized light; and a second phase difference element that is arranged on the optical path between the half mirror and the reflective polarizing element and is capable of converting linearly polarized light into circularly polarized light or circularly polarized light into linearly polarized light, wherein the optical laminate according to any one of [1] to

[10] above is arranged behind the half mirror so that the second main surface of the phase difference element faces the half mirror.

[12] According to another aspect of the present invention, there is provided a display system comprising: a display element having a display surface that emits light representing an image forward via a polarizing element; a reflective polarizing element that is arranged in front of the display element and reflects the light emitted from the display element; a first lens unit that is arranged on an optical path between the display element and the reflective polarizing element; a half mirror that is arranged between the display element and the first lens unit and transmits the light emitted from the display element and reflects the light reflected by the reflective polarizing element toward the reflective polarizing element; a first phase difference element that is arranged on the optical path between the display element and the half mirror and is capable of converting linearly polarized light into circularly polarized light or circularly polarized light into linearly polarized light; and a second phase difference element that is arranged on the optical path between the half mirror and the reflective polarizing element and is capable of converting linearly polarized light into circularly polarized light or circularly polarized light into linearly polarized light, wherein the optical laminate according to any one of [1] to

[10] above is arranged in front of the half mirror so that the second main surface of the phase difference element faces the half mirror. [Effects of the Invention]

[0008] According to the optical laminate according to the embodiment of the present invention, it is possible to effectively achieve a reduction in the weight of VR goggles while improving visibility. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic cross-sectional view showing the general configuration of an optical laminate according to one embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram illustrating the polarization state of light passing through the optical laminate shown in FIG. [Figure 3] FIG. 3 is a schematic cross-sectional view showing a general configuration of an optical laminate according to one embodiment of the present invention. [Figure 4] FIG. 4 is a schematic diagram illustrating the polarization state of light passing through the optical laminate shown in FIG. [Figure 5] FIG. 5 is a schematic cross-sectional view showing a general configuration of an optical laminate according to one embodiment of the present invention. [Figure 6] FIG. 6 is a schematic diagram illustrating the polarization state of light reflected by and emitted from the optical laminate shown in FIG. [Figure 7] FIG. 7 is a schematic cross-sectional view showing a general configuration of an optical laminate according to one embodiment of the present invention. [Figure 8] 1 is a schematic diagram showing a general configuration of a display system according to an embodiment of the present invention. [Figure 9] 9 is a schematic side view showing an example of a specific configuration of a part of the display system shown in FIG. 8. FIG. [Figure 10] 9 is a schematic side view showing an example of a specific configuration of a part of the display system shown in FIG. 8. FIG. [Figure 11] 9 is a schematic side view showing an example of a specific configuration of a part of the display system shown in FIG. 8. FIG. [Figure 12] 1 is a graph showing the difference between the ellipticity of transmitted light measured for the optical laminates produced in Examples and Comparative Examples and the ellipticity of transmitted light measured for the optical laminate of Reference Example 1. [Figure 13]1 is a graph showing the difference between the ellipticity of transmitted light measured for the optical laminates produced in Examples and Comparative Examples and the ellipticity of transmitted light measured for the optical laminate of Reference Example 1. [Figure 14] 1 is a graph showing the difference between the ellipticity of transmitted light measured for the optical laminates produced in Examples and Comparative Examples and the ellipticity of transmitted light measured for the optical laminate of Reference Example 2. [Figure 15] 1 is a graph showing the difference between the ellipticity of transmitted light measured for the optical laminates produced in Examples and Comparative Examples and the ellipticity of transmitted light measured for the optical laminate of Reference Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0010] 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.

[0011] (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°.

[0012] A. Optical laminate FIG. 1 is a schematic cross-sectional view showing the overall configuration of an optical laminate according to one embodiment of the present invention. FIG. 2 is a schematic diagram illustrating the polarization state of light passing through the optical laminate shown in FIG. 1, with some components omitted. The optical laminate 100A includes a phase difference member 20 having a first main surface 20a and a second main surface 20b facing each other, which converts linearly polarized light LP1 incident from the first main surface 20a into circularly polarized light CP1 and emits the circularly polarized light CP1 from the second main surface 20b, and a protective member 30 disposed on the second main surface 20b side of the phase difference member 20. The protective member 30 has a slow axis a and is disposed such that the angle between the slow axis a and the polarization direction b of linearly polarized light LP1 incident on the first main surface 20a of the phase difference member 20 is, for example, 15° or less, preferably 10° or less, more preferably 5° or less, and even more preferably 3° or less. Alternatively, unlike the illustrated example, the protective member 30 may be arranged so that the angle between the slow axis a and the polarization direction b of the linearly polarized light LP1 is, for example, 75° to 105°, preferably 80° to 100°, more preferably 85° to 95°, and even more preferably 87° to 93°. According to the optical laminate having the above-described configuration, the influence of the in-plane retardation of the protective member 30 can be suppressed, and the ellipticity of the light (circularly polarized) CP2 after passing through the protective member 30 can be prevented from changing significantly from the ellipticity of the light (circularly polarized) CP1 after passing through the phase difference member 20. In this specification, the term "circularly polarized light" may include not only perfectly circularly polarized light with an ellipticity of 1, but also elliptically polarized light with an ellipticity of less than 1.

[0013] The optical laminate 100A further includes a pressure-sensitive adhesive layer 40 on the first main surface 20a side of the retardation member 20. The pressure-sensitive adhesive layer 40 can be used to attach the optical laminate 100A to a desired member. Until the optical laminate 100A is used, a release liner (not shown) may be temporarily attached to the surface of the pressure-sensitive adhesive layer 40, and a surface protection film (not shown) may be temporarily attached to the surface of the protection member 30.

[0014] The phase difference member 20 and the protection member 30 are typically laminated via an adhesive layer 50a.

[0015] FIG. 3 is a schematic cross-sectional view showing the overall configuration of an optical laminate according to another embodiment of the present invention. FIG. 4 is a schematic diagram illustrating the polarization state of light passing through the optical laminate shown in FIG. 3, with some components omitted. The optical laminate 100B differs from the optical laminate 100A in that it further includes an adhesive layer 50b and an absorptive polarizing member 10, which are arranged in this order from the retardation member 20 side between the retardation member 20 and the pressure-sensitive adhesive layer 40. In the optical laminate 100B, the angle between the polarization transmission axis c of the absorptive polarizing member 10 and the slow axis a of the protective member 30 is, for example, 15° or less, preferably 10° or less, more preferably 5° or less, and even more preferably 3° or less. Alternatively, unlike the illustrated example, the angle between the polarization transmission axis c of the absorptive polarizing member 10 and the slow axis a of the protective member 30 may be, for example, 75° to 105°, preferably 80° to 100°, more preferably 85° to 95°, and even more preferably 87° to 93°. According to the optical laminate having the above-described configuration, light incident on the absorptive polarizing member 10 side passes through the absorptive polarizing member 10 and is emitted as linearly polarized light LP1, is converted into circularly polarized light CP1 by the phase difference member 20, and then passes through the protective member 30 without significantly changing its ellipticity, and is emitted as circularly polarized light CP2.

[0016] Fig. 5 is a schematic cross-sectional view showing the overall configuration of an optical laminate according to yet another embodiment of the present invention. Fig. 6 is a schematic diagram illustrating the polarization state of light reflected and emitted by the optical laminate shown in Fig. 5, with some components omitted. The optical laminate 100C differs from the optical laminate 100A in that it further includes an adhesive layer 50c, a reflective polarizing member 14, an adhesive layer 50d, and an absorptive polarizing member 15, which are arranged in this order from the retardation member 20 side between the retardation member 20 and the pressure-sensitive adhesive layer 40. In the optical laminate 100C, the angle between the polarization reflection axis d of the reflective polarizing member 14 and the slow axis a of the protective member 30 is, for example, 15° or less, preferably 10° or less, more preferably 5° or less, and even more preferably 3° or less. Alternatively, unlike the illustrated example, the angle between the polarization reflection axis d of the reflective polarizing member 14 and the slow axis a of the protective member 30 may be, for example, 75° to 105°, preferably 80° to 100°, more preferably 85° to 95°, and even more preferably 87° to 93°. Typically, the polarization reflection axis d of the reflective polarizing member 14 and the polarization absorption axis e of the absorptive polarizing member 15 are approximately parallel, and the polarization transmission axis of the reflective polarizing member 14 and the polarization transmission axis of the absorptive polarizing member 15 are approximately parallel. Depending on the purpose, the absorptive polarizing member 15 may not be provided. According to the optical laminate having the above-described configuration, linearly polarized light LP1 reflected by the reflective polarizing element 14 toward the phase difference element 20 is converted into circularly polarized light CP1 by the phase difference element 20, and can pass through the protective element 30 without significantly changing its ellipticity, and be emitted as circularly polarized light CP2.

[0017] In this specification, the polarization transmission axis, polarization absorption axis, and polarization reflection axis may be referred to as the transmission axis, absorption axis, and reflection axis, respectively, and may also be collectively referred to as the polarization axis.

[0018] In an optical laminate according to an embodiment of the present invention, when linearly polarized light is incident on the phase difference member from the first main surface side and circularly polarized light is emitted from the second main surface side, the difference in ellipticity between the circularly polarized light with a wavelength of 550 nm emitted from the second main surface side and the circularly polarized light with a wavelength of 550 nm emitted after the circularly polarized light passes through the protective member (in the illustrated example, |ellipticity of circularly polarized light CP1 with a wavelength of 550 nm−ellipticity of circularly polarized light CP2 with a wavelength of 550 nm|) is, for example, 0.02 or less, preferably 0 to 0.015, more preferably 0 to 0.01, and even more preferably 0 to 0.005.

[0019] In one embodiment, when linearly polarized light is incident on the phase difference member of the optical laminate from the first main surface side and circularly polarized light is emitted from the second main surface side, the difference between the ellipticity of the circularly polarized light having a wavelength of 450 nm that is emitted from the second main surface side and the ellipticity of the circularly polarized light having a wavelength of 450 nm that is transmitted through the protective member and emitted (in the illustrated example, |ellipticity of circularly polarized light CP1 having a wavelength of 450 nm−ellipticity of circularly polarized light CP2 having a wavelength of 450 nm|) is, for example, 0.02 or less, preferably 0 to 0.015, more preferably 0 to 0.01, and even more preferably 0 to 0.005.

[0020] In one embodiment, when linearly polarized light is incident on the phase difference member of the optical laminate from the first main surface side and circularly polarized light is emitted from the second main surface side, the difference in ellipticity between the circularly polarized light having a wavelength of 650 nm that is emitted from the second main surface side and the circularly polarized light having a wavelength of 650 nm that is transmitted through the protective member and emitted (in the illustrated example, |ellipticity of circularly polarized light CP1 having a wavelength of 650 nm−ellipticity of circularly polarized light CP2 having a wavelength of 650 nm|) is, for example, 0.02 or less, preferably 0 to 0.015, more preferably 0 to 0.01, and even more preferably 0 to 0.005.

[0021] The optical laminate may be long or may be in the form of a sheet. The planar shape of the sheet-shaped optical laminate may be, for example, a rectangle, a rectangle with rounded corners, or the like. In this specification, "long" means an elongated shape whose length is sufficiently longer than its width, and includes, for example, an elongated shape whose length is 10 times or more, preferably 20 times or more, its width. A long optical laminate can be wound into a roll.

[0022] [Phase difference material] The phase difference member 20 has a first principal surface 20a and a second principal surface 20b facing each other, and can convert linearly polarized light incident on the first principal surface 20a into circularly polarized light and emit it from the second principal surface 20b. The ellipticity of the circularly polarized light having a wavelength of 550 nm and emitted from the second principal surface of the phase difference member can be, for example, 0.90 or more, 0.92 or more, or 0.94 or more. The ellipticity of the circularly polarized light having a wavelength of 450 nm and emitted from the second principal surface of the phase difference member can be, for example, 0.80 or more, 0.83 or more, or 0.85 or more. The ellipticity of the circularly polarized light having a wavelength of 650 nm and emitted from the second principal surface of the phase difference member can be, for example, 0.78 or more, 0.80 or more, or 0.83 or more.

[0023] The surface smoothness of the retardation member 20 is, for example, 1.00 arcmin or less, preferably 0.8 arcmin or less, more preferably 0.6 arcmin or less, and even more preferably 0.4 arcmin or less. Within this range, a display system with excellent visibility can be realized. For example, by satisfying this surface smoothness, the uniformity of the in-plane retardation can be improved, and as a result, a display system with excellent display characteristics can be obtained.

[0024] The thickness variation of the phase difference member 20 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 favorably. Here, the thickness variation can be determined by measuring the thickness of a first portion located within the measurement surface 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.

[0025] The retardation member 20 includes one or more retardation layers.

[0026] In one embodiment, the phase difference member 20 is configured to convert linearly polarized light into circularly polarized light using one λ / 4 layer. Specifically, the phase difference member 20 includes a λ / 4 layer arranged so that its slow axis forms an angle of, for example, 40° to 50°, 42° to 48°, or approximately 45° with respect to the polarization direction of linearly polarized light incident on the first principal surface 20a. The phase difference member 20 configured as described above can also convert circularly polarized light incident on one principal surface into linearly polarized light and emit it from the other principal surface. In this embodiment, in a configuration in which an absorptive polarizing member 10 is arranged on the side of the phase difference member 20 opposite to the side on which the protective member 30 is arranged, as in the optical laminate 100B shown in FIG. 3, the polarization direction of the linearly polarized light is substantially the same as the transmission axis c of the absorptive polarizing member 10. Therefore, in the above configuration, the angle between the slow axis of the λ / 4 layer 21a and the transmission axis c of the absorptive polarizing member 10 can be, for example, 40° to 50°, 42° to 48°, or approximately 45°, and the angle between the slow axis of the λ / 4 layer 21a and the absorption axis of the absorptive polarizing member 10 can be, for example, 40° to 50°, 42° to 48°, or approximately 45°.

[0027] The in-plane retardation Re(550) of the λ / 4 layer 21a is, for example, 100 nm to 190 nm, may be 110 nm to 180 nm, may be 130 nm to 160 nm, or may be 135 nm to 155 nm.

[0028] The λ / 4 layer 21a 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 layer 21a 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 layer 21a is, for example, 0.75 or more.

[0029] The λ / 4 layer 21a preferably exhibits refractive index characteristics showing the 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 of the λ / 4 layer 21a is preferably 0.9 to 3, more preferably 0.9 to 2.5, still more preferably 0.9 to 1.5, and particularly preferably 0.9 to 1.3.

[0030] The surface smoothness of the λ / 4 layer 21a is, for example, 1.00 arcmin or less, preferably 0.8 arcmin or less, more preferably 0.6 arcmin or less, and still more preferably 0.4 arcmin or less.

[0031] The λ / 4 layer 21a is formed of any suitable material that can satisfy the above characteristics. The λ / 4 layer 21a can be, for example, a stretched film of a resin film or an alignment solidified layer of a liquid crystal compound.

[0032] Examples of the resin 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, acrylic resins, etc. These resins may be used alone or in combination (for example, blended or copolymerized). When the λ / 4 layer 21a exhibits inverse dispersion wavelength characteristics, a resin film containing a polycarbonate resin or a polyester carbonate resin (hereinafter sometimes simply referred to as a polycarbonate resin) can be preferably used.

[0033] 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 resins suitable for use in the λ / 4 layer 21a and methods for forming the λ / 4 layer 21a 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.

[0034] The above-mentioned liquid crystal compound alignment / solidification 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 / solidification layer" encompasses an alignment / solidification layer obtained by solidifying a liquid crystal monomer, as described below. Typically, rod-shaped liquid crystal compounds are aligned in the slow axis direction of the λ / 4 layer 21a (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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] When the λ / 4 layer 21a is a stretched resin film, its thickness 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. When the λ / 4 layer 21a is a layer for solidifying the alignment of a liquid crystal compound, its thickness 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.

[0040] In another embodiment, the phase difference member 20 is configured to convert linearly polarized light into circularly polarized light by a λ / 2 layer and a λ / 4 layer. Specifically, the phase difference member 20 includes a λ / 2 layer and a λ / 4 layer arranged in this order toward the protection member 30 side (in other words, toward the second main surface 20b side). Regarding this embodiment, referring to the optical laminate 100D shown in Figure 7, the angle between the polarization direction of the linearly polarized light (in Figure 7, the transmission axis direction of the absorptive polarizing member 10) incident from the first main surface side of the phase difference member 20 (in Figure 7, the absorptive polarizing member 10 side) and the slow axis direction of the λ / 2 layer 21b may be, for example, 55° to 85°, 70° to 80°, 72° to 78°, or approximately 75°, and in this case, the angle between the polarization direction of the linearly polarized light and the slow axis direction of the λ / 4 layer 21c may be, for example, 5° to 35°, 10° to 20°, 12° to 18°, or approximately 15°. Alternatively, the angle between the polarization direction of the linearly polarized light and the slow axis direction of the λ / 2 layer 21b may be, for example, 5° to 35°, 10° to 20°, 12° to 18°, or approximately 15°. In this case, the angle between the polarization direction of the linearly polarized light and the slow axis direction of the λ / 4 layer 21c may be, for example, 55° to 85°, 70° to 80°, 72° to 78°, or approximately 75°. The angle between the slow axis direction of the λ / 2 layer 21b and the slow axis direction of the λ / 4 layer 21c may be, for example, 50° to 70°, 55° to 65°, 57° to 63°, or approximately 60°. The retardation member 20 configured as described above can convert circularly polarized light incident from the second main surface 20b side into linearly polarized light and emit it from the first main surface 20a side.

[0041] The in-plane retardation Re(550) of the λ / 2 layer 21b 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.

[0042] The in-plane retardation Re(550) of the λ / 4 layer 21c is, for example, 100 nm to 200 nm, may be 110 nm to 180 nm, may be 130 nm to 160 nm, or may be 135 nm to 155 nm.

[0043] The λ / 2 layer 21b and the λ / 4 layer 21c each preferably exhibit 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 λ / 2 layer 21b and the λ / 4 layer 21c is, for example, 0.75 or more and less than 1, and may be 0.8 or more and 0.95 or less. Also, for example, the λ / 2 layer 21b and the λ / 4 layer 21c may each exhibit a flat wavelength dispersion characteristic in which the retardation value hardly changes depending on the wavelength of the measurement light. In this case, Re(450) / Re(550) of the λ / 2 layer 21b and the λ / 4 layer 21c may be, for example, 0.99 to 1.03, and Re(650) / Re(550) may be, for example, 0.98 to 1.02.

[0044] The λ / 2 layer 21b and the λ / 4 layer 21c each preferably exhibit a refractive index characteristic showing the relationship 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 of the λ / 2 layer 21b and the λ / 4 layer 21c is preferably 0.9 to 3, more preferably 0.9 to 2.5, still more preferably 0.9 to 1.5, and particularly preferably 0.9 to 1.3.

[0045] The surface smoothness of the λ / 2 layer 21b and the λ / 4 layer 21c is each, for example, 1.00 arcmin or less, preferably 0.8 arcmin or less, more preferably 0.6 arcmin or less, and still more preferably 0.4 arcmin or less.

[0046] The λ / 2 layer 21b and the λ / 4 layer 21c are each formed of any appropriate material that can satisfy the above characteristics. The λ / 2 layer 21b and the λ / 4 layer 21c can be, for example, a stretched resin film or an oriented and solidified layer of a liquid crystal compound, and the materials and methods for forming them can be similar to those for the λ / 4 layer 21a. When the λ / 2 layer 21b and / or the λ / 4 layer 21c have flat wavelength dispersion characteristics, preferred materials for forming them include cycloolefin resins, especially norbornene resins.

[0047] 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.

[0048] When the λ / 2 layer 21b is a stretched resin film, its thickness 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. When the λ / 2 layer 21b is a layer in which a liquid crystal compound is aligned and fixed, its thickness 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.

[0049] When the λ / 4 layer 21c is a stretched resin film, its thickness 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.When the λ / 4 layer 21c is a layer for solidifying the alignment of a liquid crystal compound, its thickness 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.

[0050] The retardation member 20 may further include other components as long as the effects of the present invention are achieved. For example, the retardation member may include a component (a so-called positive C plate) whose refractive index characteristics can exhibit the relationship nz>nx=ny in addition to the λ / 4 layer 21a, or in addition to the λ / 2 layer 21b and the λ / 4 layer 21c. The thickness direction retardation Rth(550) 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. The positive C plate may have an Re(550) of, for example, less than 0.5 nm, 0.3 nm or less, or 0.1 nm or less.

[0051] [Protective material] The protective member 30 includes a substrate. The protective member 30 may typically be a laminated film having a substrate 32 and a surface treatment layer 34. The protective member 30 having the surface treatment layer 34 may be disposed so that the surface treatment layer 34 is located on the outer side (the side opposite to the retardation member 20). For example, the surface treatment layer may be located on the outermost surface of the optical laminate.

[0052] The Re(550) of the protective member 30 may be, for example, 0.1 nm or more, 0.2 nm or more, 0.5 nm or more, 0.8 nm or more, or 1 nm or more, and may be, for example, 5.0 nm or less or 4.0 nm or less. The Re(450) of the protective member 30 may be, for example, 0.1 nm to 5.0 nm or 0.1 nm to 4.0 nm. The Re(650) of the protective member 30 may be, for example, 0.1 nm to 5.0 nm or 0.1 nm to 4.0 nm. When a protective member having the above-mentioned in-plane retardation is used, the ellipticity of the circularly polarized light emitted from the retardation member may change (e.g., decrease) when passing through the protective member. However, the change in ellipticity can be suppressed by adjusting the angle between the slow axis of the protective member, the slow axis of the retardation layer included in the retardation member, and the polarization direction of the linearly polarized light incident on the retardation member.

[0053] For example, referring to FIG. 3 , a configuration in which the phase difference member 20 converts linearly polarized light into circularly polarized light using one λ / 4 layer will be described. The angle between the polarization direction of linearly polarized light incident from the first main surface side of the phase difference member 20 and the slow axis direction of the protective member 30 is, for example, 15° or less (in other words, within a range of 0°±15°), preferably 10° or less, more preferably 5° or less, and even more preferably 3° or less, or, for example, 75° to 105° (in other words, within a range of 90°±15°), preferably 80° to 100°, more preferably 85° to 95°, and even more preferably 87° to 93°; and the angle between the slow axis direction of the λ / 4 layer 21a and the slow axis direction of the protective member 30 is, for example, 30° to 60° (in other words, within a range of 45°±15°), preferably 35° to 55°, more preferably 40° to 50°, and even more preferably 42° to 48°.

[0054] 7, the angle between the polarization direction of the linearly polarized light incident on the first main surface side of the phase difference member 20 and the slow axis direction of the protective member 30 is, for example, 15° or less, preferably 10° or less, more preferably 5° or less, and even more preferably 3° or less, or, for example, 75° to 105°, preferably 80° to 100°, more preferably 85° to 95°, and even more preferably 87° to 93°; and the angle between the slow axis direction of the λ / 4 layer 21c and the slow axis direction of the protective member 30 (when the angle between the polarization direction of the linearly polarized light and the slow axis of the λ / 2 layer 21b is 55° to 85° and the angle between the polarization direction of the linearly polarized light and the slow axis of the λ / 4 layer 21c is 5° to 35°) is, for example, 60° to 90° (in other words, within a range of 75°±15°), preferably or 65° to 85°, more preferably 70° to 80°, and even more preferably 72° to 78°, or, for example, 0° to 30° (in other words, within a range of 15°±15°), preferably 5° to 25°, more preferably 10° to 20°, and even more preferably 12° to 18°; the angle between the slow axis direction of the λ / 4 layer 21c and the slow axis direction of the protective member 30 (when the angle between the polarization direction of the linearly polarized light and the slow axis of the λ / 2 layer 21b is 5° to 35° and the angle between the polarization direction of the linearly polarized light and the slow axis of the λ / 4 layer 21c is 55° to 85°) is, for example, 0° to 30°, preferably 5° to 25°, more preferably 10° to 20°, and even more preferably 12° to 18°, or, for example, 60° to 90°, preferably 65° to 85°, more preferably 70° to 80°, and even more preferably 72° to 78°.

[0055] In the two configurations described above, when an absorptive polarizing element is disposed on the first principal surface side of the phase difference element, typically, the transmission axis direction of the absorptive polarizing element is the same as the polarization direction of linearly polarized light incident from the first principal surface side, and the absorption axis direction is a direction orthogonal to the polarization direction of the linearly polarized light. Also, when a reflective polarizing element is disposed on the first principal surface side of the phase difference element, typically, the reflection axis direction of the reflective polarizing element is the same as the polarization direction of linearly polarized light incident from the first principal surface side, and the absorption axis direction is a direction orthogonal to the polarization direction of the linearly polarized light.

[0056] The thickness of the protective member is preferably 10 μm to 80 μm, more preferably 15 μm to 60 μm, and even more preferably 20 μm to 50 μm.

[0057] The substrate 32 may be made of any appropriate resin film. The substrate 32 may be a stretched or unstretched resin film. Examples of materials that form the main component of the resin film constituting the substrate 32 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, acrylic-based, and acetate-based resins. In one embodiment, the substrate 32 is preferably made of an acrylic resin or a cellulose-based resin. For example, by forming a film from these resins by extrusion film formation, cast film formation, or the like, and stretching the film as necessary, a substrate with small in-plane retardation and excellent surface smoothness can be obtained.

[0058] The thickness of the substrate 32 is preferably 5 μm to 80 μm, more preferably 10 μm to 60 μm, and even more preferably 20 μm to 45 μm.

[0059] The thickness of the surface treatment layer 34 is preferably 0.5 μm to 10 μm, more preferably 1 μm to 7 μm, and even more preferably 2 μm to 5 μm. The surface treatment layer 34 has, for example, a hard coat layer and an antireflection layer. The antireflection layer can be provided as the outermost layer of the surface treatment layer (the outermost surface of the protective member).

[0060] In one embodiment, the surface treatment layer has substantially no in-plane retardation. The Re(550) of the surface treatment layer is, for example, less than 0.5 nm, and may be 0.2 nm or less, or 0.1 nm or less. Therefore, the in-plane retardation of the protective member may correspond to the in-plane retardation of the substrate. Furthermore, the slow axis direction of the protective member may correspond to the slow axis direction of the substrate.

[0061] The hard coat layer is typically formed by applying a hard coat layer-forming material to the substrate 32 and curing the applied layer. The hard coat layer-forming material typically contains a curable compound as a layer-forming component. Examples of the curing mechanism of the curable compound include heat curing and photocuring. Examples of the curable compound include monomers, oligomers, and prepolymers. Preferably, a polyfunctional monomer or oligomer is used as the curable compound. Examples of the polyfunctional monomer or oligomer include a monomer or oligomer having two or more (meth)acryloyl groups, a urethane (meth)acrylate or a urethane (meth)acrylate oligomer, an epoxy-based monomer or oligomer, and a silicone-based monomer or oligomer.

[0062] The thickness of the hard coat layer is preferably 0.5 μm to 10 μm, more preferably 1 μm to 7 μm, and even more preferably 2 μm to 5 μm.

[0063] The antireflection layer preferably has a laminated structure including a high refractive index layer and a low refractive index layer, in this order from the substrate 32 side.

[0064] For example, the high refractive index layer may be made of a high refractive index resin (e.g., a refractive index of 1.55 or more measured at a wavelength of 550 nm). In this case, the high refractive index layer may typically be a coating layer. Alternatively, the high refractive index layer may be made of an inorganic film. In this case, the high refractive index layer may typically be formed by physical vapor deposition such as vacuum deposition or sputtering, or chemical vapor deposition.

[0065] The thickness of the high refractive index layer is preferably 10 nm to 200 nm, and more preferably 20 nm to 150 nm.

[0066] The thickness of the low refractive index layer is preferably 10 nm to 200 nm, and more preferably 20 nm to 150 nm.

[0067] The low refractive index layer can be obtained, for example, by applying a coating liquid for forming a low refractive index layer, drying the coating, and curing the resulting coating. The coating liquid for forming a low refractive index layer may contain, for example, a resin component (curable compound), a fluorine-containing additive, hollow particles, solid particles, a solvent, and the like, and can be obtained, for example, by mixing these.

[0068] The curing mechanism of the resin component (curable compound) contained in the coating liquid for forming the low refractive index layer can be, for example, a heat-curable type or a photo-curable type. Examples of the resin component include a curable compound having at least one of an acrylate group and a methacrylate group, such as a silicone resin, a polyester resin, a polyether resin, an epoxy resin, a urethane resin, an alkyd resin, a spiroacetal resin, a polybutadiene resin, a polythiolpolyene resin, and oligomers or prepolymers of acrylates or methacrylates of polyfunctional compounds such as polyhydric alcohols. These can be used alone or in combination of two or more types.

[0069] The resin component may also contain a reactive diluent having at least one of an acrylate group and a methacrylate group. Examples of the reactive diluent include those described in JP 2008-88309 A, including monofunctional acrylates, monofunctional methacrylates, polyfunctional acrylates, and polyfunctional methacrylates. From the viewpoint of achieving excellent hardness, trifunctional or higher acrylates and trifunctional or higher methacrylates are preferably used as the reactive diluent. Examples of the reactive diluent include butanediol glycerin ether diacrylate, acrylate of isocyanuric acid, and methacrylate of isocyanuric acid. These may be used alone or in combination of two or more. A curing agent may be used to cure the resin component. Examples of the curing agent include known polymerization initiators (e.g., thermal polymerization initiators, photopolymerization initiators, etc.).

[0070] The fluorine-containing additive may be, for example, a fluorine-containing organic compound or a fluorine-containing inorganic compound. Examples of fluorine-containing organic compounds include fluorine-containing antifouling coating agents, fluorine-containing acrylic compounds, and fluorine-silicon-containing acrylic compounds. Commercially available fluorine-containing organic compounds can be used. Specific examples of commercially available products include "KY-1203" manufactured by Shin-Etsu Chemical Co., Ltd. and "Megafac" manufactured by DIC Corporation. The content of the fluorine-containing additive may be, for example, 0.05 parts by weight or more, 0.1 parts by weight or more, 0.15 parts by weight or more, 0.20 parts by weight or more, or 0.25 parts by weight or more, or 20 parts by weight or less, 15 parts by weight or less, 10 parts by weight or less, 5 parts by weight or less, or 3 parts by weight or less, per 100 parts by weight of the resin component.

[0071] Examples of hollow particles that can be used include silica particles, acrylic particles, and acrylic-styrene copolymer particles. Commercially available hollow silica particles (e.g., trade names "Sururia 5320" and "Sururia 4320" manufactured by JGC Catalysts and Chemicals Industries, Ltd.) can be used. The weight-average particle diameter of the hollow particles can be, for example, 30 nm or more, 40 nm or more, 50 nm or more, 60 nm or more, or 70 nm or more, or 150 nm or less, 140 nm or less, 130 nm or less, 120 nm or less, or 110 nm or less. The shape of the hollow particles is not particularly limited, but is preferably approximately spherical. Specifically, the aspect ratio of the hollow particles is preferably 1.5 or less. The content of the hollow particles may be, for example, 30 parts by weight or more, 50 parts by weight or more, 70 parts by weight or more, 90 parts by weight or more, or 100 parts by weight or more, or 300 parts by weight or less, 270 parts by weight or less, 250 parts by weight or less, 200 parts by weight or less, or 180 parts by weight or less, relative to 100 parts by weight of the resin component.

[0072] Examples of the solid particles include silica particles, zirconia particles, and titania particles. Commercially available solid silica particles (e.g., products manufactured by Nissan Chemical Industries, Ltd. under the trade names "MEK-2140Z-AC," "MIBK-ST," and "IPA-ST") can be used. The weight-average particle diameter of the solid particles may be, for example, 5 nm or more, 10 nm or more, 15 nm or more, 20 nm or more, or 25 nm or more, or 330 nm or less, 250 nm or less, 200 nm or less, 150 nm or less, or 100 nm or less. The shape of the hollow particles is not particularly limited, but is preferably substantially spherical. Specifically, the aspect ratio of the hollow particles is preferably 1.5 or less. The content of the solid particles may be, for example, 5 parts by weight or more, 10 parts by weight or more, 15 parts by weight or more, 20 parts by weight or more, or 25 parts by weight or more, and may be 150 parts by weight or less, 120 parts by weight or less, 100 parts by weight or less, or 80 parts by weight or less, relative to 100 parts by weight of the resin component.

[0073] Any appropriate solvent can be used as the solvent. Examples of the solvent include alcohols such as methanol, ethanol, isopropyl alcohol, butanol, TBA (tertiary butyl alcohol), and 2-methoxyethanol; ketones such as acetone, methyl ethyl ketone, MIBK (methyl isobutyl ketone), and cyclopentanone; esters such as methyl acetate, ethyl acetate, butyl acetate, and PMA (propylene glycol monomethyl ether acetate); ethers such as diisopropyl ether and propylene glycol monomethyl ether; glycols such as ethylene glycol and propylene glycol; cellosolves such as ethyl cellosolve and butyl cellosolve; aliphatic hydrocarbons such as hexane, heptane, and octane; and aromatic hydrocarbons such as benzene, toluene, and xylene. These solvents may be used alone or in combination. The solvent content may be, for example, such that the weight of the solids relative to the total weight of the coating liquid for forming the low refractive index layer is, for example, 0.1 wt % or more, 0.3 wt % or more, 0.5 wt % or more, 1.0 wt % or more, or 1.5 wt % or more, or 20 wt % or less, 15 wt % or less, 10 wt % or less, 5 wt % or less, or 3 wt % or less.

[0074] The coating liquid for forming the low refractive index layer can be applied by known coating methods such as fountain coating, die coating, spin coating, spray coating, gravure coating, roll coating, and bar coating. The drying temperature of the coating film is, for example, 30°C to 200°C, and the drying time is, for example, 30 to 90 seconds. The curing of the coating film can be carried out by, for example, heating or light irradiation (typically, ultraviolet irradiation). A high-pressure mercury lamp, for example, is used as a light source for light irradiation. The dose of ultraviolet irradiation is 50 mJ / cm as the cumulative exposure dose at an ultraviolet wavelength of 365 nm. 2 ~500mJ / cm 2 It is preferable that:

[0075] [Absorptive polarizing material] The absorptive polarizing members 10 and 15 may typically include a resin film containing a dichroic material (sometimes referred to as an absorptive polarizing film). The thickness of the absorptive polarizing film is, for example, 1 μm or more and 20 μm or less, and may be 2 μm or more and 15 μm or less, 12 μm or less, 10 μm or less, 8 μm or less, or 5 μm or less. A protective layer may be provided on one or both sides of the absorptive polarizing film.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] The crossed transmittance (Tc) of the absorptive polarizing element (absorptive polarizing film) 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 element (absorptive polarizing film) is, for example, 41.0% to 45.0%, and preferably 42.0% or more. The polarization degree (P) of the absorptive polarizing element (absorptive polarizing film) is, for example, 99.0% to 99.997%, and preferably 99.9% or more.

[0081] [Reflective polarizing material] The reflective polarizing element 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 having a multilayer structure (sometimes referred to as a reflective polarizing film). In this case, the thickness of the reflective polarizing element is, for example, 10 μm to 150 μm, preferably 20 μm to 100 μm, and more preferably 30 μm to 60 μm.

[0082] Commercially available reflective polarizing films include, for example, "DBEF" and "APF" manufactured by 3M, and "APCF" manufactured by Nitto Denko Corporation.

[0083] 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%.

[0084] [Adhesive layer] The adhesive layer 40 can be composed of any appropriate adhesive. Specific examples include acrylic adhesives, rubber adhesives, silicone adhesives, polyester adhesives, urethane adhesives, epoxy adhesives, and polyether adhesives. By adjusting the type, number, combination, and compounding ratio of the monomers forming the base resin of the adhesive, as well as the amount of crosslinking agent, reaction temperature, reaction time, etc., it is possible to prepare an adhesive having desired properties according to the purpose. The base resin of the adhesive may be used alone or in combination of two or more types. An acrylic resin is preferably used as the base resin. Specifically, the adhesive layer 40 is preferably composed of an acrylic adhesive.

[0085] The thickness of the pressure-sensitive adhesive layer 40 is, for example, 12 μm or more, preferably 15 μm or more, and for example, 100 μm or less, preferably 80 μm or less.

[0086] [Adhesive layer] The adhesive layers 50a to 50d 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, 0.01 μm to 60 μm. In one embodiment, the retardation member 20 and the protection member 30 are bonded together via a pressure-sensitive adhesive layer. When the adhesive layer is a pressure-sensitive adhesive layer, the same explanation as for the pressure-sensitive adhesive layer 40 can be applied.

[0087] B. Display System FIG. 8 is a schematic diagram showing the overall configuration of an example of a display system to which the optical laminate described in Section A can be applied. FIG. 8 schematically illustrates the arrangement and shape of each component of a display system 2. The display system 2 includes a display element 12, a reflective polarizing member 14, a first lens unit 16, a half mirror 18, a first phase difference member 22, a second phase difference member 23, and a second lens unit 24. The reflective polarizing member 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 reflective polarizing member 14, and the half mirror 18 is disposed between the display element 12 and the first lens unit 16. The first phase difference member 22 is disposed on the optical path between the display element 12 and the half mirror 18, and the second phase difference member 23 is disposed on the optical path between the half mirror 18 and the reflective polarizing member 14. The first phase difference member 22 and the second phase difference member 23 can convert linearly polarized light into circularly polarized light or circularly polarized light into linearly polarized light, respectively. Although not shown, an absorptive polarizing member may be disposed between the reflective polarizing member 14 and the second lens portion 24 from the viewpoint of improving visibility. In this case, the reflection axis of the reflective polarizing member 14 and the absorption axis of the absorptive polarizing member may be disposed approximately parallel to each other, and the transmission axis of the reflective polarizing member 14 and the transmission axis of the absorptive polarizing member may be disposed approximately parallel to each other.

[0088] The half mirror or the components arranged forward from the first lens section (in the illustrated example, the half mirror 18, first lens section 16, second phase difference member 23, reflective polarizing member 14, and second lens section 24) may be collectively referred to as the lens section (lens section 4).

[0089] 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.

[0090] The first linearly polarized light incident on the first phase difference member 22 is converted into first circularly polarized light. The first phase difference member 22 may be provided integrally with the display element 12. For example, the first phase difference member 22 may be provided integrally with a polarizing member that may be included in the display element 12.

[0091] The half mirror 18 transmits the light emitted from the display element 12 and reflects the light reflected by the reflective polarizing member 14 back toward the reflective polarizing member 14. The half mirror 18 is provided integrally with the first lens portion 16.

[0092] The second phase difference member 23 can transmit light reflected by the reflective polarizing member 14 and the half mirror 18 through the reflective polarizing member 14. The second phase difference member 23 may be provided integrally with the first lens unit 16 or the second lens unit 24. In the latter case, the second phase difference member 23 can be provided integrally with the second lens unit 24 together with the reflective polarizing member 14.

[0093] The first circularly polarized light emitted from the first phase difference member 22 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 23. The second linearly polarized light emitted from the second phase difference member 23 is reflected toward the half mirror 18 without passing through the reflective polarizing member 14. At this time, the polarization direction of the second linearly polarized light incident on the reflective polarizing member 14 is the same as the reflection axis of the reflective polarizing member. Therefore, the second linearly polarized light incident on the reflective polarizing member 14 is reflected by the reflective polarizing member 14.

[0094] The second linearly polarized light reflected by the reflective polarizing element 14 is converted into second circularly polarized light by the second phase difference element 23, and the second circularly polarized light emitted from the second phase difference element 23 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 element 23. The third linearly polarized light is transmitted through the reflective polarizing element 14. At this time, the polarization direction of the third linearly polarized light incident on the reflective polarizing element 14 is the same direction as the transmission axis of the reflective polarizing element. Therefore, the third linearly polarized light incident on the reflective polarizing element 14 is transmitted through the reflective polarizing element.

[0095] The light transmitted through the reflective polarizing member 14 passes through the second lens portion 24 and enters the eye 26 of the user.

[0096] For example, the absorption axis of the polarizing member included in the display element 12 and the reflection axis of the reflective polarizing member 14 may be arranged substantially parallel to each other or may be arranged substantially perpendicular to each other.

[0097] In one embodiment, the optical laminate described in Section A can be applied to the display system 2 as an optical laminate including a first phase difference member 22. In this embodiment, the optical laminate described in Section A is disposed behind the half mirror 18 so that the second main surface 20b of the phase difference member 20 faces the half mirror 18, and thereby the phase difference member 20 can function as the first phase difference member 22. For example, as shown in FIG. 9 , by bonding the optical laminate 100B to a member 13 constituting a display element with a pressure-sensitive adhesive layer 40, a display system can be constructed in which the first retardation member 22 is integrated with the display element 12. In this display system, the absorptive polarizing member 10 is a polarizing member that can be included in the display element 12, and light emitted from the absorptive polarizing member 10 becomes first linearly polarized light. The first linearly polarized light is converted into first circularly polarized light by the first retardation member 22, and can maintain high ellipticity even after passing through the protective member 30. As a result, polarization disturbance in the display system can be suppressed, and visibility can be improved.

[0098] In one embodiment, the optical laminate described in Section A can be applied to the display system 2 as an optical laminate including the second phase difference member 23. In this embodiment, the optical laminate described in Section A is disposed in front of the half mirror 18 (but behind the second lens portion 24) so ​​that the second main surface 20b of the phase difference member 20 faces the half mirror 18, and thereby the phase difference member 20 can function as the second phase difference member 23. For example, as shown in FIG. 10 , by bonding the optical laminate 100C to the second lens unit 24 with the pressure-sensitive adhesive layer 40, a display system can be configured in which the second phase difference member 23 is integrated with the second lens unit 24. In the lens unit 4 of the display system, the second linearly polarized light emitted from the second phase difference member 23 toward the reflective polarizing member 14 is reflected by the reflective polarizing member 14, enters the second phase difference member 23 from the first principal surface side 20a, and is converted into second circularly polarized light. The second circularly polarized light emitted from the second principal surface 20b of the second phase difference member 23 can maintain high ellipticity even after passing through the protection member 30. As a result, polarization disturbance in the display system can be suppressed, and visibility can be improved.

[0099] In one embodiment, the optical laminate described in Section A can be applied to the display system 2 as an optical laminate including a second phase difference member 23. The optical laminate used in this embodiment includes a phase difference member 20 configured to convert linearly polarized light into circularly polarized light using one λ / 4 layer. The optical laminate is placed in front of the half mirror 18 so that the first main surface 20a of the phase difference member 20 faces the half mirror 18, and this allows the phase difference member 20 to function as the second phase difference member 23. For example, as shown in FIG. 11 , by bonding the optical laminate 100A to the first lens unit 16 with a pressure-sensitive adhesive layer 40, a display system can be constructed in which the second phase difference member 23 is integrated with the first lens unit 16 (in the illustrated example, the reflective polarizing member 14 is integrated with the second lens unit 24 with an adhesive layer 50e). In the lens unit 4 of the display system, the first circularly polarized light emitted from the first phase difference member 22 enters the second phase difference member 23 from the first principal surface side 20a and is converted into the second linearly polarized light. The second linearly polarized light emitted from the second principal surface 20b of the second phase difference member 23 can maintain its polarization state even after passing through the protection member 30 (in other words, changes in ellipticity can be suppressed). Furthermore, the circularly polarized light reflected by the half mirror enters the second phase difference member 23 from the first principal surface side 20a and is converted into the third linearly polarized light. The third linearly polarized light emitted from the second main surface 20b of the second phase difference member 23 can maintain its polarization state even after passing through the protection member 30. As a result, polarization disturbance in the display system can be suppressed, and visibility can be improved. [Example]

[0100] The present invention will be specifically described below using examples, but the present invention is not limited to these examples. The test and evaluation methods used in the examples are as follows. The term "parts" means "parts by weight" unless otherwise specified, and the term "%" means "% by weight" unless otherwise specified.

[0101] (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 element The polarizing element'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 visibility. The degree of polarization of the polarizing element was calculated from the obtained Tp and Tc using the following formula: Degree of polarization (%)={(Tp-Tc) / (Tp+Tc)} 1 / 2 ×100 (4) Smoothness The smoothness was measured using a phase-shifting laser interferometer (Zygo, product name "DynaFiz"). Specifically, the measurement object was laminated onto a microslide glass (Matsunami Glass Industry, product name "S200200") to prevent the inclusion of foreign matter, bubbles, or 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 left to cool at room temperature for 30 minutes or more to obtain a measurement sample. The measurement sample was placed on a vibration-proof measurement table, and a single-wavelength (633 nm) laser was used to measure the relative displacement within a specified area (a 30 mm diameter circle) by interfering with a standard whose flatness was guaranteed. For the analysis, the smoothness (unit: arcmin) was defined as double the value (equivalent to 2σ) of the angle index "Slopemagnitude RMS" obtained by extracting frequency values ​​from 0.1 / mm to 1 / mm. (5) Shaft angle The axial angle was measured using a Mueller matrix polarimeter (manufactured by AXOMETRICS, product name "AxoScan") at a measurement wavelength of 550 nm.

[0102] [Production Example 1: Preparation of Absorptive Polarizing Member A] (Fabrication of an absorption polarizing film) A long, amorphous isophthalic acid copolymerized polyethylene terephthalate film (thickness: 100 μm) with 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.

[0103] (Fabrication of absorptive polarizing members) A 20 μm-thick acrylic film having a lactone ring structure 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 to a thickness of 2 μm, and the films were attached using a roller. The adhesive was then cured by irradiating it with UV light from the acrylic film side. The resin substrate was then peeled off. In this way, an absorptive polarizing member A having a configuration of [acrylic film / absorptive polarizing film] was obtained. The single transmittance (Ts) of absorptive polarizing member A was 43.4%, and the polarization degree was 99.993%.

[0104] [Manufacturing Example 2A: Preparation of λ / 4 Layer A] 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 added. After purging the reactor with nitrogen under reduced pressure, the reactor was heated with a heat 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 and was maintained at this temperature while simultaneously reducing the pressure to 13.3 kPa in 90 minutes after reaching 220°C. 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 in a condenser at 45°C. 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, the second reactor was heated and depressurized, reaching an internal temperature of 240°C and a pressure of 0.2 kPa in 50 minutes. Thereafter, polymerization was allowed to proceed until a predetermined stirring power was reached, at which point nitrogen was introduced into the reactor to restore pressure, and the resulting polyester carbonate resin 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, and wound into a roll. This resulted in a 47 μm thick λ / 4 layer A. The λ / 4 layer A had Re(450) of 119 nm, Re(550) of 139 nm, and Re(650) of 147 nm, and exhibited inverse dispersion wavelength characteristics. The Nz coefficient (590) of the λ / 4 layer A was 1.2. The smoothness of the λ / 4 layer A was 0.25 arcmin.

[0105] [Manufacturing Example 2B: Preparation of λ / 4 Layer B] A long norbornene-based resin film (manufactured by Zeon Corporation, trade name "Zeonor," 40 μm thick) was stretched longitudinally at the free end by adjusting the stretch ratio and stretching temperature so that the in-plane retardation Re(590) was 135 nm, producing a 34 μm thick λ / 4 layer B. The λ / 4 layer B had a refractive index characteristic of nx > ny = nz. The Re(450) / Re(550) ratio of the λ / 4 layer B was 1.004, indicating a roughly flat dispersion wavelength characteristic. The surface smoothness of the λ / 4 layer B was 0.32 arcmin.

[0106] [Manufacturing Example 2C: Preparation of λ / 2 Layer A] A 32-μm-thick λ / 2 layer A was produced by longitudinally stretching a long norbornene-based resin film (manufactured by Zeon Corporation, trade name "Zeonor," thickness 50 μm) at the free end, adjusting the stretch ratio and stretching temperature so that the in-plane retardation Re(590) was 280 nm. The λ / 2 layer A had a refractive index characteristic of nx > ny = nz. The Re(450) / Re(550) of the λ / 2 layer A was 1.004, indicating a roughly flat dispersion wavelength characteristic. The surface smoothness of the λ / 2 layer A was 0.42 arcmin.

[0107] [Manufacturing Example 3A: Preparation of protective member A] (Preparation of Hard Coat Layer-Forming Material) A hard coat layer-forming material was prepared by mixing 50 parts of a urethane acrylic oligomer (manufactured by Shin-Nakamura Chemical Co., Ltd., "NK Oligo UA-53H"), 30 parts of a multifunctional acrylate whose main component is pentaerythritol triacrylate (manufactured by Osaka Organic Chemical Industry Ltd., trade name "Viscoat #300"), 20 parts of 4-hydroxybutyl acrylate (manufactured by Osaka Organic Chemical Industry Ltd.), 1 part of a leveling agent (manufactured by DIC Corporation, "GRANDIC PC4100"), and 3 parts of a photopolymerization initiator (manufactured by Ciba Japan, "Irgacure 907") and diluting with methyl isobutyl ketone to a solids concentration of 50%.

[0108] (Preparation of Coating Solution for Forming High Refractive Index Layer) 100 parts by weight of a multifunctional acrylate (manufactured by Arakawa Chemical Industries, Ltd., trade name "Opstar KZ6728", solid content 20% by weight), 3 parts by weight of a leveling agent (manufactured by DIC Corporation, "GRANDIC PC4100"), and 3 parts by weight of a photopolymerization initiator (manufactured by BASF, trade name "OMNIRAD907", solid content 100% by weight) were mixed. The mixture was diluted with butyl acetate as a dilution solvent to a solid content of 12% by weight, and stirred to prepare a coating liquid for forming a high refractive index layer.

[0109] (Preparation of Coating Solution for Forming Low Refractive Index Layer) 100 parts by weight of a polyfunctional acrylate containing pentaerythritol triacrylate as the main component (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name "Viscoat #300", solid content 100 wt%), 150 parts by weight of hollow nanosilica particles (manufactured by JGC Catalysts and Chemicals Industries, Ltd., trade name "Sururia 5320", solid content 20 wt%, weight average particle diameter 75 nm), 50 parts by weight of solid nanosilica particles (manufactured by Nissan Chemical Industries, Ltd., trade name "MEK-2140Z-AC", solid content 30 wt%, weight average particle diameter 10 nm), 12 parts by weight of a fluorine-containing additive (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KY-1203", solid content 20 wt%), and 3 parts by weight of a photopolymerization initiator (manufactured by BASF, trade name "OMNIRAD907", solid content 100 wt%) were mixed. To this mixture, a mixed solvent of TBA (tertiary butyl alcohol), MIBK (methyl isobutyl ketone), and PMA (propylene glycol monomethyl ether acetate) in a weight ratio of 60:25:15 was added as a dilution solvent to make the total solid content 4% by weight, and the mixture was stirred to prepare a coating liquid for forming a low refractive index layer.

[0110] The above hard coat layer-forming material was applied to an acrylic film (thickness: 40 μm) having a lactone ring structure and heated at 90°C for 1 minute. After heating, the applied layer was irradiated with a high-pressure mercury lamp at an integrated light intensity of 300 mJ / cm. 2 The coating layer was cured by irradiating it with ultraviolet light of 1000 W at ... Next, the coating solution for forming the high refractive index layer was applied onto the hard coat layer using a wire bar, and the applied coating solution was heated at 80°C for 1 minute and dried to form a coating film. The dried coating film was irradiated with a high-pressure mercury lamp at an integrated light intensity of 300 mJ / cm. 2 The coating was cured by irradiating it with ultraviolet light of 1000 kJ / cm 2 , thereby forming a high refractive index layer having a thickness of 140 nm. Next, the coating solution for forming the low refractive index layer was applied onto the high refractive index layer using a wire bar, and the applied coating solution was heated at 80°C for 1 minute and dried to form a coating film. After drying, the coating film was irradiated with a high-pressure mercury lamp with an integrated light intensity of 300 mJ / cm. 2The coating was cured by irradiating it with ultraviolet light of 1000 kJ / cm 2 , thereby forming a low refractive index layer having a thickness of 105 nm. In this way, a protective member A having a structure of [acrylic film / hard coat layer / high refractive index layer / low refractive index layer] was obtained. The thickness of the protective member A was 44 μm, and the surface smoothness was 0.4 arcmin. The Re(450), Re(550), and Re(650) of the protective member A were 2.2 nm, 1.8 nm, and 1.7 nm, respectively.

[0111] [Manufacturing Example 3B: Preparation of Protective Member B] The same hard coat layer-forming material as in Production Example 3A was applied to a triacetyl cellulose film (manufactured by Fujifilm Corporation, product name "TG60UL," thickness 60 μm) and heated at 90°C for 1 minute. After heating, the applied layer was irradiated with a high-pressure mercury lamp at an integrated light intensity of 300 mJ / cm. 2 The coating layer was cured by irradiation with ultraviolet light of 1000 kJ / cm, thereby producing a triacetyl cellulose film (thickness 72 μm) on which a hard coat layer having a thickness of 12 μm was formed. Next, the same coating solution for forming a high refractive index layer as in Production Example 3A was applied onto the hard coat layer using a wire bar, and the applied coating solution was heated at 80°C for 1 minute and dried to form a coating film. After drying, the coating film was irradiated with a high-pressure mercury lamp at an integrated light intensity of 300 mJ / cm. 2 The coating was cured by irradiating it with ultraviolet light of 1000 kJ / cm 2 , thereby forming a high refractive index layer having a thickness of 140 nm. Next, the same coating solution for forming a low refractive index layer as in Production Example 3A was applied onto the high refractive index layer using a wire bar, and the applied coating solution was heated at 80°C for 1 minute and dried to form a coating film. After drying, the coating film was irradiated with a high-pressure mercury lamp with an integrated light dose of 300 mJ / cm. 2 The coating was cured by irradiating it with ultraviolet light of 1000 kJ / cm 2 , thereby forming a low refractive index layer having a thickness of 105 nm. In this way, a protective member B having a structure of [TAC film / hard coat layer / high refractive index layer / low refractive index layer] was obtained. The thickness of protective member B was 72 μm, and the surface smoothness was 0.9 arcmin. The Re(450), Re(550), and Re(650) of protective member B were 0.2 nm, 1.1 nm, and 1.4 nm, respectively.

[0112] [Examples 1-1 to 1-3, Comparative Examples 1-1 to 1-3, Reference Example 1] The absorptive polarizing element A, λ / 4 layer A, and protective element A produced in the above production example were punched out into rectangular shapes so that the optical axis formed a predetermined angle with respect to the side direction, and laminated to produce an optical laminate with the configuration and axis angle shown in Table 1. In this case, the absorptive polarizing element A and the λ / 4 layer A were laminated via an acrylic pressure-sensitive adhesive (thickness 5 μm), so that the absorptive polarizing film side surface of the absorptive polarizing element A faced the λ / 4 layer A. In addition, the λ / 4 layer A and protective element A were laminated via an acrylic pressure-sensitive adhesive (thickness 12 μm), so that the substrate side surface of the protective element A faced the λ / 4 layer A. In addition, an optical laminate not including the protective element A was produced as Reference Example 1.

[0113] [Table 1]

[0114] [Examples 2-1 to 2-3, Comparative Examples 2-1 to 2-3] The absorptive polarizing element A, λ / 4 layer A, and protective element B produced in the above manufacturing example were punched out into rectangular shapes so that the optical axis formed a predetermined angle with respect to the side direction, and were laminated to produce an optical laminate with the configuration and axis angle shown in Table 2. In this case, the absorptive polarizing element A and the λ / 4 layer A were laminated via an acrylic adhesive (thickness 5 μm), so that the absorptive polarizing film side surface of the absorptive polarizing element A faced the λ / 4 layer A. In addition, the λ / 4 layer A and protective element B were laminated via an acrylic adhesive (thickness 12 μm), so that the substrate side surface of the protective element B faced the λ / 4 layer A.

[0115] [Table 2]

[0116] Using a Mueller matrix polarimeter (product name "AxoScan" manufactured by AXOMETRICS), light was incident from the front on the surface of the absorptive polarizing member A of the optical laminates obtained in Examples 1-1 to 2-3, Comparative Examples 1-1 to 2-3, and Reference Example 1, and the ellipticity of the light emitted from the opposite surface (polar angle 0°) at wavelengths of 450 nm, 550 nm, and 650 nm was measured. The difference between the ellipticity measured for each optical laminate and the ellipticity measured for the optical laminate of Reference Example 1 (ellipticity in Reference Example 1 - ellipticity in the Example or Comparative Example) is shown in Figures 12 and 13. The ellipticities of emitted light having wavelengths of 450 nm, 550 nm, and 650 nm measured for the optical laminate of Reference Example 1 were 0.908, 0.983, and 0.860, respectively.

[0117] As shown in Fig. 12, in the optical laminates of Comparative Examples 1-1 to 1-3, the change in ellipticity (difference in ellipticity) of transmitted light (emitted light) compared to the optical laminate of Reference Example 1 exceeds 0.02 at some wavelengths, but in the optical laminates of Examples 1-1 to 1-3, the change is kept to 0.02 or less at all wavelengths. Furthermore, as shown in Fig. 13, in the optical laminates of Comparative Examples 2-1 to 2-3, the change in ellipticity of transmitted light compared to the optical laminate of Reference Example 1 exceeds 0.01 at some wavelengths, but in the optical laminates of Examples 2-1 to 2-3, the change is kept to 0.01 or less at all wavelengths. As described above, in the optical laminates of the Examples, the change in ellipticity of transmitted light compared to Reference Example is more suppressed than in the optical laminates of the Comparative Examples.

[0118] [Examples 3-1 to 3-3, Comparative Examples 3-1 to 3-3, Reference Example 2] The absorptive polarizing element A, λ / 2 layer A, λ / 4 layer B, and protective element A prepared in the above manufacturing example were punched into rectangular shapes so that the optical axis formed a predetermined angle with respect to the side direction, and laminated to produce an optical laminate with the configuration and axis angle shown in Table 3. The absorptive polarizing element A and the λ / 2 layer A were laminated together via an acrylic adhesive (thickness: 5 μm), with the absorptive polarizing film-side surface of the absorptive polarizing element A facing the λ / 2 layer A. The λ / 2 layer A and the λ / 4 layer B were laminated together via an acrylic adhesive (thickness: 5 μm). The λ / 4 layer B and protective element A were laminated together via an acrylic adhesive (thickness: 12 μm), with the substrate-side surface of the protective element A facing the λ / 4 layer B. An optical laminate not including protective element A was also prepared as Reference Example 2.

[0119] [Table 3]

[0120] [Examples 4-1 to 4-3, Comparative Examples 4-1 to 4-3] Except for using protective member B instead of protective member A, optical laminates having the configurations and axis angles shown in Table 4 were produced in the same manner as in Examples 3-1 to 3-3 and Comparative Examples 3-1 to 3-3.

[0121] [Table 4]

[0122] Using a Mueller matrix polarimeter (product name "AxoScan" manufactured by AXOMETRICS), light was incident from the front onto the surface on side A of the absorptive polarizing member of the optical laminates obtained in Examples 3-1 to 4-3, Comparative Examples 3-1 to 4-3, and Reference Example 2, and the ellipticity of the light emitted from the opposite surface (polar angle 0°) was measured at wavelengths of 450 nm, 550 nm, and 650 nm. The difference between the ellipticity measured for each optical laminate and the ellipticity measured for the optical laminate of Reference Example 2 (ellipticity in Reference Example 2 - ellipticity in the example or comparative example) is shown in Figures 14 and 15. The ellipticities of emitted light having wavelengths of 450 nm, 550 nm, and 650 nm measured for the optical laminate of Reference Example 2 were 0.873, 0.944, and 0.934, respectively.

[0123] As shown in Fig. 14, in the optical laminates of Comparative Examples 3-1 to 3-3, the change in ellipticity of transmitted light (emitted light) compared to the optical laminate of Reference Example 2 exceeds 0.02 at some wavelengths, but in the optical laminates of Examples 3-1 to 3-3, the change is kept to 0.02 or less at all wavelengths. Also, as shown in Fig. 15, in the optical laminates of Comparative Examples 4-1 to 4-3, the change in ellipticity of transmitted light compared to the optical laminate of Reference Example 2 exceeds 0.01 at some wavelengths, but in the optical laminates of Examples 4-1 to 4-3, the change is kept to 0.01 or less at all wavelengths. As described above, in the optical laminates of the Examples, the change in ellipticity of transmitted light compared to Reference Example is more suppressed than in the optical laminates of the Comparative Examples.

[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, 4 lens portion, 10 absorptive polarizing member, 12 display element, 12a display surface, 14 reflective polarizing member, 15 absorptive polarizing member, 16 first lens portion, 18 half mirror, 20 retardation member, 21a λ / 4 layer, 21b λ / 2 layer, 21c λ / 4 layer, 22 first retardation member, 23 second retardation member, 24 second lens portion, 30 protective member, 40 adhesive layer, 100 optical laminate.

Claims

1. a retardation element having a first principal surface and a second principal surface opposed to each other, converting linearly polarized light incident from the first principal surface side into circularly polarized light and outputting the circularly polarized light from the second principal surface side; and a protection member having a slow axis and arranged on the second principal surface side of the retardation element, the angle between the slow axis of the protective member and the polarization direction of the linearly polarized light is 15° or less or 75° to 105°; Optical laminate.

2. the retardation member includes a λ / 4 layer having an Re(550) of 100 nm to 190 nm, 2. The optical laminate according to claim 1, wherein the angle formed between the slow axis of the protective member and the slow axis of the λ / 4 layer is 30° to 60°.

3. further including a polarizing member disposed on the first principal surface side of the phase difference member, 2. The optical laminate according to claim 1, wherein the angle formed between the slow axis of the protective member and the polarization axis of the polarizing member is 15° or less or 75° to 105°.

4. 2. The optical laminate according to claim 1, wherein the difference between the ellipticity of light with a wavelength of 550 nm in the circularly polarized light emitted from the second main surface side of the phase difference member and the ellipticity of light with a wavelength of 550 nm in the circularly polarized light that is transmitted through the protective member and emitted is 0.02 or less.

5. The optical laminate according to claim 4, which satisfies at least one of the following (i) and (ii): (i) a difference between the ellipticity of light having a wavelength of 450 nm in the circularly polarized light emitted from the second main surface side of the retardation member and the ellipticity of light having a wavelength of 450 nm in the circularly polarized light that is transmitted through the protective member and emitted is 0.02 or less; (ii) The difference between the ellipticity of the light having a wavelength of 650 nm in the circularly polarized light emitted from the second main surface side of the phase difference member and the ellipticity of the light having a wavelength of 650 nm in the circularly polarized light that is transmitted through the protective member and emitted is 0.02 or less.

6. the protective member includes a substrate, The optical laminate according to claim 1 , wherein the substrate contains at least one resin selected from an acrylic resin and a triacetyl cellulose resin.

7. The optical laminate according to claim 6 , wherein the protective member further comprises an antireflection layer disposed on the side of the substrate opposite to the side on which the retardation member is disposed.

8. The optical laminate according to claim 1, wherein the protective member has an Re(550) of 0.5 nm or more.

9. The optical laminate according to claim 1 , wherein the retardation member and the protective member are laminated via a pressure-sensitive adhesive layer.

10. a display element having a display surface that emits light representing an image forward via a polarizing member; a reflective polarizing member disposed in front of the display element and reflecting light emitted from the display element; a first lens portion disposed on an optical path between the display element and the reflective polarizing member; 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 reflective polarizing element toward the reflective polarizing element; a first phase difference member that is disposed on an optical path between the display element and the half mirror and that can convert linearly polarized light into circularly polarized light or circularly polarized light into linearly polarized light; a second phase difference member that is disposed on an optical path between the half mirror and the reflective polarizing member and that can convert linearly polarized light into circularly polarized light or circularly polarized light into linearly polarized light, The optical laminate according to claim 1 , wherein the retardation member is arranged so as to function as the first retardation member or the second retardation member.

11. a display element having a display surface that emits light representing an image forward via a polarizing member; a reflective polarizing member disposed in front of the display element and reflecting light emitted from the display element; a first lens portion disposed on an optical path between the display element and the reflective polarizing member; 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 reflective polarizing element toward the reflective polarizing element; a first phase difference member that is disposed on an optical path between the display element and the half mirror and that can convert linearly polarized light into circularly polarized light or circularly polarized light into linearly polarized light; a second phase difference member that is disposed on an optical path between the half mirror and the reflective polarizing member and that can convert linearly polarized light into circularly polarized light or circularly polarized light into linearly polarized light, A display system, wherein the optical laminate according to claim 1 is disposed behind the half mirror so that the second main surface of the phase difference member faces the half mirror.

12. a display element having a display surface that emits light representing an image forward via a polarizing member; a reflective polarizing member disposed in front of the display element and reflecting light emitted from the display element; a first lens portion disposed on an optical path between the display element and the reflective polarizing member; 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 reflective polarizing element toward the reflective polarizing element; a first phase difference member that is disposed on an optical path between the display element and the half mirror and that can convert linearly polarized light into circularly polarized light or circularly polarized light into linearly polarized light; a second phase difference member that is disposed on an optical path between the half mirror and the reflective polarizing member and that can convert linearly polarized light into circularly polarized light or circularly polarized light into linearly polarized light, A display system, wherein the optical laminate according to claim 1 is disposed in front of the half mirror so that the second main surface of the phase difference member faces the half mirror.

Images