JP7516458B2 - Lens portion, laminate, display, manufacturing method of display, and display method - Google Patents

Description

The present invention relates to a lens portion, a laminate, a display body, a manufacturing method for a display body, and a display method.

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

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. Since VR goggles are being considered for use in various situations, there is a demand for them to be lightweight and have high definition. Lightweightness can be achieved, for example, by making the lenses used in VR goggles thinner. On the other hand, there is also a demand for the development of optical components suitable for display systems using thin lenses. Furthermore, in VR display systems, conversion and reflection between circularly polarized light and linearly polarized light are used, but there is a problem in that light that should be reflected is transmitted and is viewed as an afterimage (ghost).

JP 2021-103286 A

In view of the above, the primary objective of the present invention is to provide a lens section that can realize lightweight, high-definition VR goggles and also suppress afterimages.

1. A lens unit according to an embodiment of the present invention is used in a display system that displays an image to a user. The lens unit includes: a reflective polarizing element that reflects light that is emitted forward from a display surface of a display element that displays an image and passes through a polarizing element and a first λ/4 element; an absorptive polarizing element disposed in front of the reflective polarizing element; a first lens unit disposed on an optical path between the display element and the reflective polarizing element; a second lens unit disposed in front of the absorptive polarizing element; a half mirror disposed between the display element and the first lens unit, which transmits the light emitted from the display element and reflects the light reflected by the reflective polarizing element toward the reflective polarizing element; and a second λ/4 element disposed on an optical path between the half mirror and the reflective polarizing element. The second λ/4 element and the first lens unit are integrated, and the reflective polarizing element, the absorptive polarizing element, and the second lens unit are integrated.
2. In the lens portion described above in 1, the reflection axis of the reflective polarizing member and the absorption axis of the absorptive polarizing member may be arranged parallel to each other.
3. In the lens portion according to 1 or 2 above, the first lens portion and the half mirror may be integral with each other.
4. In the lens portion according to any one of 1 to 3 above, an angle between an absorption axis of the polarizing member included in the display element and a slow axis of the first λ/4 member may be 40° to 50°, and an angle between an absorption axis of the polarizing member included in the display element and a slow axis of the second λ/4 member may be 40° to 50°.
5. In the lens portion described in any one of 1 to 4 above, the second λ/4 member and the first lens portion may be integrated via an adhesive layer, and the reflective polarizing member, the absorptive polarizing member, and the second lens portion may be integrated via an adhesive layer.

6. A laminate according to an embodiment of the present invention is used for the lens portion according to any one of 1 to 5 above, and has the reflective polarizing member, the absorptive polarizing member, and the second lens portion.
7. A laminate according to another embodiment of the present invention is used for the lens portion according to any one of 1 to 5 above, and has the second λ/4 member and the first lens portion.
8. In the laminate according to 6 above, the reflection axis of the reflective polarizing member and the absorption axis of the absorptive polarizing member may be arranged parallel to each other.
9. In the laminate according to the above item 7, the reflection axis of the reflective polarizing member and the absorption axis of the absorptive polarizing member may be arranged parallel to each other.

10. A display according to an embodiment of the present invention has a lens portion according to any one of 1 to 5 above.
11. A method for manufacturing a display according to an embodiment of the present invention is a method for manufacturing a display having a lens portion according to any one of 1 to 5 above.

12. A display method according to an embodiment of the present invention includes the steps of: passing light representing an image emitted through a polarizing element and a first λ/4 element through a half mirror and a first lens unit; passing the light that has passed through the half mirror and the first lens unit through a second λ/4 element; reflecting the light that has passed through the second λ/4 element toward the half mirror with a reflective polarizing element; making the light reflected by the reflective polarizing element and the half mirror transmittable through the reflective polarizing element by the second λ/4 element; and transmitting the light that has transmitted through the reflective polarizing element through an absorptive polarizing element; wherein the second λ/4 element and the first lens unit are integrated, and the reflective polarizing element, the absorptive polarizing element, and the second lens unit are integrated.

The lens portion according to the embodiment of the present invention can reduce the weight of VR goggles, increase their definition, and also reduce afterimages.

1 is a schematic diagram showing a general configuration of a display system according to an embodiment of the present invention. FIG. 2 is a schematic perspective view showing an example of a multilayer structure included in a reflective polarizing film.

Below, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments. Furthermore, in order to make the description clearer, the drawings may show the width, thickness, shape, etc. of each part more diagrammatically than the embodiments, but these are merely examples and do not limit the interpretation of the present invention.

(Definition of terms and symbols)
The definitions of terms and symbols used in this specification are as follows.
(1) Refractive index (nx, ny, nz)
"nx" is the refractive index in the direction in which the in-plane refractive index is maximum (i.e., the slow axis direction), "ny" is the refractive index in the 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 having a wavelength of λ nm at 23° C. For example, "Re(550)" is the in-plane retardation measured with light having a wavelength of 550 nm at 23° C. Re(λ) is calculated by the formula: Re(λ)=(nx−ny)×d, where d (nm) is the thickness of the layer (film).
(3) Retardation in the thickness direction (Rth)
"Rth(λ)" is the retardation in the thickness direction measured with light having a wavelength of λ nm at 23° C. For example, "Rth(550)" is the retardation in the thickness direction measured with light having a wavelength of 550 nm at 23° C. Rth(λ) is calculated by the formula: Rth(λ)=(nx-nz)×d, where d (nm) is the thickness of the layer (film).
(4) Nz Coefficient The Nz coefficient is calculated by Nz=Rth/Re.
(5) Angle When referring to an angle in this specification, the angle includes both clockwise and counterclockwise angles with respect to a reference direction. Thus, for example, "45°" means ±45°.

1 is a schematic diagram showing the general configuration of a display system according to one embodiment of the present invention. In FIG. 1, the arrangement and shape of each component of the display system 2 are illustrated. The display system 2 includes a display element 12, a reflective polarizing member 32, an absorptive polarizing member 34, a first lens unit 16, a half mirror 18, a first phase difference member 20, a second phase difference member 22, and a second lens unit 24. The reflective polarizing member 32 is disposed in front of the display surface 12a side 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 32, and the half mirror 18 is disposed between the display element 12 and the first lens unit 16. The first phase difference member 20 is disposed on the optical path between the display element 12 and the half mirror 18, and the second phase difference member 22 is disposed on the optical path between the half mirror 18 and the reflective polarizing member 32. The absorptive polarizing element 34 may be disposed in front of the reflective polarizing element 32. The reflection axis of the reflective polarizing element and the absorption axis of the absorptive polarizing element may be disposed approximately parallel to each other, and the transmission axis of the reflective polarizing element and the transmission axis of the absorptive polarizing element may be disposed approximately parallel to each other. The reflective polarizing element 32 and the absorptive polarizing element 34 may be collectively referred to as a reflecting portion. The second lens portion 24 is disposed in front of the absorptive polarizing element 34.

In an embodiment of the present invention, as shown in the illustrated example, the second phase difference member 22 (hereinafter, the second phase difference member may be referred to as the second λ/4 member) and the first lens section 16 are integrated, and the reflective polarizing member 32, the absorptive polarizing member 34, and the second lens section 24 are integrated. The second λ/4 member 22 and the first lens section 16, as well as the reflective polarizing member 32, the absorptive polarizing member 34, and the second lens section 24 are integrated (typically laminated) via, for example, an adhesive layer (not shown). In other words, the second λ/4 member 22 and the absorptive polarizing member 34 are configured to be separated (as separate bodies). With such a configuration, it is possible to prevent an increase in transmittance due to a misalignment of the axial arrangement of the optical axes (slow axis, reflection axis, and absorption axis) of each member. More specifically, it is as follows. The present inventors have found that when the second λ/4 member and the absorptive polarizing member 34 (and, inevitably, the reflective polarizing member 32) are integrated, the second λ/4 member may be deformed and/or shifted in the slow axis direction due to deformation (typically shrinkage) in a high-temperature environment caused by heating or the like of the absorptive polarizing film constituting the absorptive polarizing member. Furthermore, they have found that such deformation and/or shift in the slow axis direction causes light that should be reflected by the reflective polarizing member to pass through the reflective polarizing member without being reflected, and such transmitted light generates an afterimage (ghost). In contrast, with the above-mentioned configuration, the transmission of light that should be reflected can be suppressed, and the afterimage (ghost) can be suppressed well. In addition, if necessary, any appropriate low-reflection film may be further provided (or may be further integrated) on the surface of the reflective polarizing member 32 on the side on which the absorptive polarizing member 34 is not arranged and/or the surface of the second λ/4 member 22 on the side on which the first lens portion 16 is not arranged. The adhesive layer may be formed of an adhesive or a pressure-sensitive adhesive. The thickness of the adhesive layer is, for example, 0.05 μm to 30 μm, preferably 3 μm to 20 μm, and more preferably 5 μm to 15 μm.

The components arranged in front of the half mirror (in the illustrated example, the half mirror 18, the first lens section 16, the second phase difference member 22, the reflective polarizing member 32, the absorptive polarizing member 34, and the second lens section 24) may be collectively referred to as the lens section (lens section 4).

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 a first linearly polarized light.

The first phase difference member 20 is a λ/4 member that can convert the first linearly polarized light incident on the first phase difference member 20 into the first circularly polarized light (hereinafter, the first phase difference member may be referred to as the first λ/4 member). The first phase difference member 20 may be provided integrally with the display element 12.

The half mirror 18 transmits the light emitted from the display element 12 and reflects the light reflected by the reflective polarizing element 32 toward the reflective polarizing element 32. The half mirror 18 is integrally formed with the first lens portion 16.

The second phase difference member 22 is a λ/4 member that allows light reflected by the reflective polarizing member 32 and the half mirror 18 to pass through the reflective polarizing member 32. The second phase difference member 22 is integrally provided with the first lens portion 16.

The first circularly polarized light emitted from the first λ/4 member 20 passes through the half mirror 18 and the first lens portion 16, and is converted into the second linearly polarized light by the second λ/4 member 22. The second linearly polarized light emitted from the second λ/4 member 22 is reflected toward the half mirror 18 without passing through the reflective polarizing member 32. At this time, the polarization direction of the second linearly polarized light incident on the reflective polarizing member 32 is the same as the reflection axis of the reflective polarizing member. Therefore, the second linearly polarized light incident on the reflective polarizing member is reflected by the reflective polarizing member.

The second linearly polarized light reflected by the reflective polarizing element 32 is converted into the second circularly polarized light by the second λ/4 element 22, and the second circularly polarized light emitted from the second λ/4 element 22 passes through the first lens unit 16 and is reflected by the half mirror 18. The second circularly polarized light reflected by the half mirror 18 passes through the first lens unit 16 and is converted into the third linearly polarized light by the second λ/4 element 22. The third linearly polarized light passes through the reflective polarizing element 32. At this time, the polarization direction of the third linearly polarized light incident on the reflective polarizing element 32 is the same as the transmission axis of the reflective polarizing element. Therefore, the third linearly polarized light incident on the reflective polarizing element 32 passes through the reflective polarizing element.

The light transmitted through the reflective polarizing element 32 passes through the absorptive polarizing element 34 and the second lens portion 24 and enters the user's eye 26. The polarization direction of the third linearly polarized light transmitted through the reflective polarizing element 32 is the same as the transmission axis of the absorptive polarizing element.

For example, the absorption axis of the polarizing member included in the display element 12 and the reflection axis of the reflective polarizing member 32 may be arranged approximately parallel to each other or approximately perpendicular to each other. The angle between the absorption axis of the polarizing member included in the display element 12 and the slow axis of the first phase difference member 20 is, for example, 40° to 50°, may be 42° to 48°, or may be about 45°. The angle between the absorption axis of the polarizing member included in the display element 12 and the slow axis of the second phase difference member 22 is, for example, 40° to 50°, may be 42° to 48°, or may be about 45°. The slow axis of the first phase difference member 20 and the slow axis of the second phase difference member 22 may be arranged approximately parallel to each other, for example.

The in-plane phase difference Re(550) of the first phase difference member 20 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.

The first phase difference member 20 preferably exhibits an inverse dispersion wavelength characteristic in which the phase difference value increases according to the wavelength of the measurement light. The Re(450)/Re(550) of the first phase difference member 20 is, for example, less than 1 and may be 0.95 or less, or may be less than 0.90 or even 0.85 or less. The Re(450)/Re(550) of the first phase difference member 20 is, for example, 0.75 or more.

In one embodiment, the first phase difference member 20 satisfies all of Re(400)/Re(550)<0.85, Re(650)/Re(550)>1.03, and Re(750)/Re(550)>1.05. The first phase difference member 20 preferably satisfies at least one selected from 0.65<Re(400)/Re(550)<0.80 (preferably, 0.7<Re(400)/Re(550)<0.75), 1.0<Re(650)/Re(550)<1.25 (preferably, 1.05<Re(650)/Re(550)<1.20), and 1.05<Re(750)/Re(550)<1.40 (preferably, 1.08<Re(750)/Re(550)<1.36), more preferably satisfies at least two, and even more preferably satisfies all.

The first phase difference member 20 preferably has a refractive index characteristic that satisfies the relationship nx>ny≧nz. Here, "ny=nz" includes not only the case where ny and nz are completely equal, but also the case where they are substantially equal. Therefore, there may be cases where ny<nz, as long as the effect of the present invention is not impaired. The Nz coefficient of the first phase difference member 20 is preferably 0.9 to 3, more preferably 0.9 to 2.5, even more preferably 0.9 to 1.5, and particularly preferably 0.9 to 1.3.

The first phase difference member 20 is formed of any suitable material that can satisfy the above characteristics. The first phase difference member 20 can be, for example, a stretched resin film or an oriented and solidified layer of a liquid crystal compound.

Examples of resins contained in the resin film include polycarbonate-based resins, polyester carbonate-based resins, polyester-based resins, polyvinyl acetal-based resins, polyarylate-based resins, cyclic olefin-based resins, cellulose-based resins, polyvinyl alcohol-based resins, polyamide-based resins, polyimide-based resins, polyether-based resins, polystyrene-based resins, acrylic-based resins, and the like. These resins may be used alone or in combination (e.g., blended or copolymerized). When the first phase difference member 20 exhibits reverse dispersion wavelength characteristics, a resin film containing a polycarbonate-based resin or a polyester carbonate-based resin (hereinafter sometimes simply referred to as a polycarbonate-based resin) may be preferably used.

As the polycarbonate-based resin, any suitable polycarbonate-based resin can be used as long as the effects of the present invention can be obtained. For example, the polycarbonate-based resin contains a structural unit derived from a fluorene-based dihydroxy compound, a structural unit derived from an isosorbide-based dihydroxy compound, and a structural unit derived from at least one dihydroxy compound selected from the group consisting of alicyclic diol, alicyclic dimethanol, di-, tri- or polyethylene glycol, and alkylene glycol or spiro glycol. Preferably, the polycarbonate-based resin contains a structural unit derived from a fluorene-based dihydroxy compound, a structural unit derived from an isosorbide-based dihydroxy compound, a structural unit derived from an alicyclic dimethanol and/or a structural unit derived from a di-, tri- or polyethylene glycol; more preferably, it contains a structural unit derived from a fluorene-based dihydroxy compound, a structural unit derived from an isosorbide-based dihydroxy compound, and a structural unit derived from a di-, tri- or polyethylene glycol. The polycarbonate-based resin may contain a structural unit derived from another dihydroxy compound as necessary. Details of polycarbonate-based resins that can be suitably used for the first phase difference member and methods for forming the first phase difference member 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.

The thickness of the first phase difference member 20, which is made of a stretched resin film, is, for example, 10 μm to 100 μm, preferably 10 μm to 70 μm, more preferably 10 μm to 40 μm, and even more preferably 20 μm to 30 μm.

The above-mentioned liquid crystal compound alignment solidified layer is a layer in which the liquid crystal compound is aligned in a predetermined direction within the layer and the alignment state is fixed. The "alignment solidified layer" is a concept that includes an alignment solidified layer obtained by hardening a liquid crystal monomer as described below. In the first phase difference member, typically, rod-shaped liquid crystal compounds are aligned in the slow axis direction of the first phase difference member (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.

The alignment solidified layer of the liquid crystal compound (liquid crystal alignment solidified 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 adopted 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 deposition method and photoalignment treatment. Any appropriate conditions can be adopted as the treatment conditions for various alignment treatments depending on the purpose.

The alignment of liquid crystal compounds is achieved by treating them at a temperature that exhibits a liquid crystal phase according to the type of liquid crystal compound. By carrying out such temperature treatment, the liquid crystal compounds take on a liquid crystal state, and the liquid crystal compounds are aligned according to the alignment treatment direction of the substrate surface.

In one embodiment, the alignment state is fixed by cooling the liquid crystal compound aligned as described above. If 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.

As the liquid crystal compound, any suitable liquid crystal polymer and/or liquid crystal monomer can be used. 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, for example, in JP 2006-163343 A, JP 2006-178389 A, and WO 2018/123551 A. The descriptions in these publications are incorporated herein by reference.

The thickness of the first phase difference member 20, which is composed of a liquid crystal alignment solidified layer, is, for example, 1 μm to 10 μm, preferably 1 μm to 8 μm, more preferably 1 μm to 6 μm, and even more preferably 1 μm to 4 μm.

The in-plane phase difference Re(550) of the second phase difference member 22 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.

The second phase difference member 22 preferably exhibits an inverse dispersion wavelength characteristic in which the phase difference value increases according to the wavelength of the measurement light. The Re(450)/Re(550) of the second phase difference member 22 is, for example, less than 1 and may be 0.95 or less, or may be less than 0.90 or even 0.85 or less. The Re(450)/Re(550) of the second phase difference member 22 is, for example, 0.75 or more.

In one embodiment, the second phase difference member 22 satisfies all of Re(400)/Re(550)<0.85, Re(650)/Re(550)>1.03, and Re(750)/Re(550)>1.05. The second phase difference member 22 preferably satisfies at least one selected from 0.65<Re(400)/Re(550)<0.80 (preferably, 0.7<Re(400)/Re(550)<0.75), 1.0<Re(650)/Re(550)<1.25 (preferably, 1.05<Re(650)/Re(550)<1.20), and 1.05<Re(750)/Re(550)<1.40 (preferably, 1.08<Re(750)/Re(550)<1.36), more preferably satisfies at least two, and even more preferably satisfies all.

The second phase difference member 22 preferably has a refractive index characteristic that satisfies the relationship nx>ny≧nz. Here, "ny=nz" includes not only the case where ny and nz are completely equal, but also the case where they are substantially equal. Therefore, there may be cases where ny<nz, as long as the effect of the present invention is not impaired. The Nz coefficient of the second phase difference member 22 is preferably 0.9 to 3, more preferably 0.9 to 2.5, even more preferably 0.9 to 1.5, and particularly preferably 0.9 to 1.3.

The second phase difference member 22 is formed of any appropriate material that can satisfy the above characteristics. The second phase difference member 22 can be, for example, a stretched resin film or an oriented and solidified layer of a liquid crystal compound. The same explanation as for the first phase difference member 20 can be applied to the second phase difference member 22 that is composed of a stretched resin film or an oriented and solidified layer of a liquid crystal compound. The first phase difference member 20 and the second phase difference member 22 may be members of the same configuration (forming material, thickness, optical properties, etc.) or may be members of different configurations.

The reflective polarizing element can transmit light polarized parallel to its transmission axis (typically, linearly polarized light) while maintaining its polarization state, and can reflect light in other polarization states. A typical reflective polarizing element is made of a film (sometimes called a reflective polarizing film) with a multilayer structure. 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.

Figure 2 is a schematic perspective view showing an example of a multilayer structure included in a reflective polarizing film. The multilayer structure 32a has alternating layers A having birefringence and layers B having substantially no birefringence. The total number of layers constituting the multilayer structure may be 50 to 1000. For example, the refractive index nx in the x-axis direction of layer A is larger than the refractive index ny in the y-axis direction, and the refractive index nx in the x-axis direction and the refractive index ny in the y-axis direction of layer B are substantially the same, and the refractive index difference between layers A and B is large in the x-axis direction and substantially zero in the y-axis direction. As a result, the x-axis direction can be the reflection axis, and the y-axis direction can be the transmission axis. The refractive index difference between layers A and B in the x-axis direction is preferably 0.2 to 0.3.

The A layer is typically made of a material that exhibits birefringence when stretched. Examples of such materials include naphthalene dicarboxylic acid polyesters (e.g., polyethylene naphthalate), polycarbonates, and acrylic resins (e.g., polymethyl methacrylate). The B layer is typically made of a material that does not substantially exhibit birefringence even when stretched. Examples of such materials include copolyesters of naphthalene dicarboxylic acid and terephthalic acid. The multilayer structure can be formed by combining coextrusion and stretching. For example, the material constituting the A layer and the material constituting the B layer are extruded and then multilayered (e.g., using a multiplier). The resulting multilayer laminate is then stretched. The x-axis direction in the illustrated example can correspond to the stretching direction.

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

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

The absorptive polarizing member is typically composed of a resin film containing a dichroic material (sometimes referred to as an absorptive polarizing film). In this case, the thickness of the absorptive polarizing member 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.

The absorptive polarizing film may be made from a single layer of resin film, or may be made using a laminate of two or more layers.

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

The dyeing with iodine is carried out, for example, by immersing the PVA-based film in an aqueous iodine solution. The stretching ratio of the uniaxial stretching is preferably 3 to 7 times. The stretching may be carried out after the dyeing process, or may be carried out while dyeing. Alternatively, the film may be stretched and then dyed. If necessary, the PVA-based film may be subjected to a swelling process, a crosslinking process, a washing process, a drying process, etc.

Examples of the laminate produced using the above-mentioned 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 coated on the resin substrate. The absorptive polarizing film obtained using a laminate of a resin substrate and a PVA-based resin layer coated 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 to obtain a laminate of the resin substrate and the PVA-based resin layer; stretching and dyeing the laminate to make the PVA-based resin layer into an absorptive polarizing film. In this embodiment, preferably, a polyvinyl alcohol-based resin layer containing a halide and a polyvinyl alcohol-based resin is formed on one side of the resin substrate. The stretching typically includes immersing the laminate in an aqueous boric acid solution to stretch it. Furthermore, the stretching may further include air-stretching the laminate at a high temperature (e.g., 95°C or higher) before stretching in the boric acid aqueous solution, if necessary. In addition, in this embodiment, the laminate is preferably subjected to a drying shrinkage treatment in which the laminate is heated while being conveyed 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 air-assisted stretching treatment, a dyeing treatment, an underwater stretching treatment, and a drying shrinkage treatment in this order. By introducing the auxiliary stretching, it is possible to increase the crystallinity of PVA even when PVA is applied onto a thermoplastic resin, and it is possible to achieve high optical properties. At the same time, by increasing the orientation of PVA in advance, problems such as a decrease in the orientation of PVA or dissolution can be prevented when the PVA is immersed in water in the subsequent dyeing step or stretching step, and it is possible to achieve high optical properties. Furthermore, when the PVA-based resin layer is immersed in a liquid, the disorder 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 the absorptive polarizing film obtained through a process in which the laminate is immersed in a liquid, such as a dyeing process and an underwater stretching process. Furthermore, the optical properties can be improved by shrinking the laminate in the width direction by a drying shrinkage process. 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 on the peeled surface of the resin substrate/absorptive polarizing film laminate from which the resin substrate is peeled, or on the surface opposite to the peeled surface. Details of the manufacturing method of such an absorptive polarizing film are described, for example, in JP-A-2012-73580 and JP-A-6470455. The entire disclosures of these publications are incorporated herein by reference.

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

The cross transmittance (Tc) of the reflective portion is preferably 0.5% or less, more preferably 0.1% or less, and even more preferably 0.05% or less. By satisfying such cross transmittance, it is possible to suppress the user's perception of afterimages (ghosts), and excellent display characteristics can be achieved. The single transmittance (Ts) of the reflective portion is preferably 40.0% to 45.0%, and more preferably 41.0% or more. The polarization degree (P) of the reflective portion is preferably 99.0% to 99.997%, and more preferably 99.9% or more.

The optical characteristics of the reflecting portion may correspond to the optical characteristics of a reflective polarizing element, or may correspond to the optical characteristics of a laminate of a reflective polarizing element and an absorptive polarizing element. The optical characteristics can be achieved extremely well by combining a reflective polarizing element with an absorptive polarizing element.

As described above, the second λ/4 member and the first lens portion, and the reflective polarizing member, the absorptive polarizing member, and the second lens portion are each integrated. The embodiments of the present invention also include each of such integrated bodies (laminates). Each laminate can be used, for example, in the display system of FIG. 1 (representatively, the lens portion thereof).

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. The thicknesses are values measured by the following measuring method.
<Thickness>
The thickness of 10 μm or less was measured using a scanning electron microscope (manufactured by JEOL Ltd., product name "JSM-7100F"), and the thickness of more than 10 μm was measured using a digital micrometer (manufactured by Anritsu Corporation, product name "KC-351C").

[Production Example 1: Preparation of Polarizing Plate 1]
A polyvinyl alcohol film having an average polymerization degree of 2400, a saponification degree of 99.9 mol%, and a thickness of 30 μm was immersed in warm water at 30° C., and uniaxially stretched while swelling so that the length of the PVA-based resin film became 2.0 times the original length. Next, the film was immersed in a 0.3 wt % (weight ratio: iodine/potassium iodide=0.5/8) iodine solution at 30° C., and dyed while uniaxially stretching so that the length of the PVA-based resin film became 3.0 times the original length. After that, the film was stretched in an aqueous solution of 4 wt % boric acid and 5 wt % potassium iodide so that the length of the PVA-based resin film became 6 times the original length. Further, the film was impregnated with iodine ions in an aqueous solution of 3 wt % potassium iodide (iodine impregnation bath), and then dried in an oven at 60° C. for 4 minutes to obtain a polarizing film having a thickness of 12 μm.
A long HC-TAC film and a long acrylic resin film (thickness 20 μm) serving as an inner protective layer were attached to both sides of the polarizing film with their longitudinal directions aligned to obtain a polarizing plate 1. The HC-TAC film is a film in which a hard coat (HC) layer (thickness 7 μm) is formed on a triacetyl cellulose (TAC) film (thickness 25 μm), and the TAC film was attached to the polarizer side.

[Manufacturing Example 2: Preparation of λ/4 member 1]
In a batch polymerization apparatus consisting of two vertical reactors equipped with stirring blades and a reflux condenser 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 × 10-2 parts by weight (6.78 × 10-5 mol) of calcium acetate monohydrate as a catalyst were charged. After the inside of the reactor was replaced with nitrogen under reduced pressure, the reactor was heated with a heat medium, and stirring was started when the inside temperature reached 100 ° C. The internal temperature was allowed to reach 220°C 40 minutes after the start of the temperature rise, and the pressure was controlled to maintain this temperature while simultaneously starting decompression, and the pressure was reduced to 13.3 kPa in 90 minutes after reaching 220°C. Phenol vapor by-produced during the polymerization reaction was led to a reflux condenser at 100°C, a small amount of monomer components contained in the phenol vapor were returned to the reactor, and uncondensed phenol vapor was led to a condenser at 45°C and recovered. Nitrogen was introduced into the first reactor to restore the pressure to atmospheric pressure once, and the oligomerized reaction liquid in the first reactor was transferred to the second reactor. Next, the temperature rise and decompression in the second reactor were started, and the internal temperature was set to 240°C and the pressure to 0.2 kPa in 50 minutes. Thereafter, polymerization was allowed to proceed until a predetermined stirring power was reached. Nitrogen was introduced into the reactor at the time the predetermined power was reached to restore the pressure, and the polyester carbonate resin produced was extruded into water, and the strands were cut to obtain pellets.
The obtained polyester carbonate resin (pellets) was vacuum-dried at 80 ° C. for 5 hours, and then a long resin film having 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 setting temperature: 250 ° C.), a T-die (width 200 mm, setting temperature: 250 ° C.), a chill roll (setting temperature: 120 to 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 stretching ratio of 2.7 times. As a result, a retardation film (λ / 4 member 1) having a thickness of 47 μm, Re (590) of 143 nm, and Nz coefficient of 1.2 was obtained.

[Manufacturing Example 3: Preparation of λ/4 member 2]
55 parts by weight of the compound represented by formula (I), 25 parts by weight of the compound represented by formula (II), and 20 parts by weight of the compound represented by formula (III) were added to 400 parts by weight of cyclopentanone (CPN), and then heated to 60°C and stirred to dissolve. Thereafter, the solution of the above-mentioned compound was returned to room temperature, and 3 parts by weight of Irgacure 907 (manufactured by BASF Japan), 0.2 parts by weight of Megafac F-554 (manufactured by DIC), and 0.1 parts by weight of p-methoxyphenol (MEHQ) were added to the solution of the above-mentioned compound, and further stirred. The solution after stirring was transparent and uniform. The obtained solution was filtered through a 0.20 μm membrane filter to obtain a polymerizable composition.
Also, a polyimide solution for an alignment film was applied to a glass substrate having a thickness of 0.7 mm by spin coating, and a coating film was obtained by drying at 100° C. for 10 minutes and then baking at 200° C. for 60 minutes. The obtained coating film was subjected to a rubbing treatment using a commercially available rubbing device to form an alignment film.
Next, the polymerizable composition obtained above was applied to a substrate (substantially an alignment film) by spin coating, and dried at 100° C. for 2 minutes. After the obtained coating film was cooled to room temperature, it was irradiated with ultraviolet light for 30 seconds at an intensity of 30 mW/cm ² using a high pressure mercury lamp. As a result, a liquid crystal alignment solidified layer (λ/4 member 2) having a thickness of 1.5 μm, Re(590) of 143 nm, and Nz coefficient of 1.0 was obtained.

[Example 1]
A polarizing plate 1 was attached to a reflective polarizing film ("APCFG4" manufactured by Nitto Denko Corporation) via an adhesive so that the reflection axis of the reflective polarizing film and the absorption axis of the polarizing film of the polarizing plate 1 were arranged parallel to each other, to obtain a laminate of a reflective polarizing film/polarizing plate 1. The laminate was cut to a size of 100 mm vertically and 100 mm horizontally, and then the polarizing plate 1 side was attached to glass (lens substitute) via an adhesive to obtain an evaluation sample E1-1 having a configuration of a reflective polarizing film/polarizing plate 1/glass. Here, the cutting was performed so that the absorption axis of the polarizing film of the polarizing plate was in the horizontal direction (0°). On the other hand, the retardation film 1 (second λ/4 member) of Production Example 2 was cut to a size of 100 mm vertically and 100 mm horizontally, and then attached to the same glass as the evaluation sample E1-1 via an adhesive to obtain an evaluation sample E1-2 having a configuration of (λ/4) member 1/glass. Here, the retardation film was cut so that the slow axis of the retardation film was at 45° counterclockwise when viewed from above with the glass surface facing down, with the horizontal direction being 0°.

[Comparative Example 1]
A laminate of reflective polarizing film/polarizing plate 1 was obtained in the same manner as in Example 1. Next, the retardation film 1 (second λ/4 member) of Production Example 2 was attached to the surface of the reflective polarizing film on the side on which the polarizing plate was not provided via an adhesive. Here, the retardation film 1 was attached so that its slow axis was at an angle of 45° to the reflection axis of the reflective polarizing film and the absorption axis of the polarizing film of the polarizing plate 1. In this way, a laminate 1 having a configuration of (λ/4) member 1/reflective polarizing film/polarizing plate 1 was obtained. After cutting the laminate 1 into a size of 100 mm in length and 100 mm in width, the λ/4 member 1 side was attached to the same glass as in Example 1 via an adhesive, and an evaluation sample C1 having a configuration of glass/(λ/4) member 1/reflective polarizing film/polarizing plate 1 was obtained. Here, the polarizing plate was cut so that the absorption axis was in the horizontal direction (0°) and the slow axis of the retardation film was at 45° counterclockwise when viewed from above with the glass surface facing down, with the horizontal direction being 0°.

[Comparative Example 2]
A laminate 1 was obtained in the same manner as in Comparative Example 1. The laminate 1 was cut into a size of 100 mm in length and 100 mm in width, and then the polarizing plate 1 side was attached to the same glass as in Example 1 via an adhesive to obtain an evaluation sample C2 having a configuration of (λ/4) member 1/reflective polarizing film/polarizing plate 1/glass. Here, the cut was performed so that the absorption axis of the polarizing plate was in the horizontal direction (0°) and the slow axis of the retardation film was 135° counterclockwise when viewed from above with the glass surface facing down with the horizontal direction at 0°.

The evaluation samples obtained in the examples and comparative examples were subjected to the following evaluations. The evaluation results are shown in Table 1.
<Evaluation>
The evaluation sample was stored in an oven at 85° C. for 120 hours, and the dimensional shrinkage rates in the longitudinal and transverse directions were measured. Next, the angles of the slow axis and the absorption axis were calculated from the dimensional shrinkage rates, and the axis deviation from 45° was calculated based on the angles of the slow axis and the absorption axis. The results are shown in Table 1.

As is clear from Table 1, according to the embodiment of the present invention, the dimensional change rate of the second λ/4 member is smaller than that of the comparative example, and as a result, the axial misalignment between the second λ/4 member and the reflective polarizing film is smaller. This means that an increase in transmittance due to axial misalignment of the second λ/4 member can be prevented, and afterimages (ghosts) can be effectively suppressed. It was also confirmed that similar results could be obtained when the λ/4 member 2 of Manufacturing Example 3 was used instead of the λ/4 member 1 of Manufacturing Example 2.

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 embodiments can be replaced with configurations that are substantially the same as those shown in the above-described embodiments, that have the same effects, or that can achieve the same purpose.

The lens portion according to the embodiment of the present invention can be used, for example, in a display such as a VR goggle.

Reference Signs List 2 display system 4 lens section 12 display element 16 first lens section 18 half mirror 20 first phase difference member 22 second phase difference member 24 second lens section 32 reflective polarizing member 34 absorptive polarizing member

Claims (10)

1. A lens unit for use in a display system for displaying an image to a user, comprising:
a reflective polarizing member that reflects light that is emitted forward from a display surface of a display element that displays an image and that has passed through the polarizing member and the first λ/4 member;
an absorptive polarizing member disposed in front of the reflective polarizing member;
a first lens portion disposed on an optical path between the display element and the reflective polarization type member;
A second lens portion disposed in front of the absorptive 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 member toward the reflective polarizing member;
a second λ/4 member disposed on an optical path between the half mirror and the reflective polarizing member;
The second λ/4 member and the first lens portion are integrated, and the reflective polarizing member, the absorptive polarizing member and the second lens portion are integrated ,
the second λ/4 member and the reflective polarizing member are spaced apart from each other,
the half mirror, the first lens portion, and the second λ/4 member are arranged in this order from the display element side .
Lens part. The lens portion according to claim 1, wherein the reflection axis of the reflective polarizing element and the absorption axis of the absorptive polarizing element are arranged parallel to each other. The lens unit according to claim 1, wherein the first lens unit and the half mirror are integral. the angle between the absorption axis of the polarizing member included in the display element and the slow axis of the first λ/4 member is 40° to 50°;
2. The lens portion according to claim 1, wherein an angle between an absorption axis of the polarizing member included in the display element and a slow axis of the second λ/4 member is 40° to 50°. The lens section according to claim 1, wherein the second λ/4 member and the first lens section are integrated via an adhesive layer, and the reflective polarizing member, the absorptive polarizing member, and the second lens section are integrated via an adhesive layer. The lens portion according to any one of claims 1 to 5 is used,
The polarizing lens includes the reflective polarizing member, the absorptive polarizing member, and the second lens portion.
A laminate for the lens portion of the display system . The lens portion according to any one of claims 1 to 5 is used,
The second λ/4 member and the first lens portion are provided.
A laminate for the lens portion of the display system . The laminate for the lens portion of the display system according to claim 6 , wherein a reflection axis of the reflective polarizer and an absorption axis of the absorptive polarizer are arranged parallel to each other. A display having a lens portion according to any one of claims 1 to 5. A step of passing light representing an image outputted through the polarizing member and the first λ/4 member through a half mirror and a first lens unit;
A step of passing the light that has passed through the half mirror and the first lens portion through a second λ/4 member;
A step of reflecting the light that has passed through the second λ/4 member toward the half mirror by a reflective polarizing member;
allowing the light reflected by the reflective polarizing member and the half mirror to pass through the reflective polarizing member by the second λ/4 member;
and transmitting the light transmitted through the reflective polarizing member through an absorptive polarizing member and a second lens portion,
The second λ/4 member and the first lens portion are integrated, and the reflective polarizing member, the absorptive polarizing member and the second lens portion are integrated ,
the second λ/4 member and the reflective polarizing member are spaced apart from each other,
the half mirror, the first lens portion, and the second λ/4 member are arranged in this order from the display element side .
Display method.

Images