JP7516455B2 - 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 a variety of 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.

JP 2021-103286 A

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

1. A lens unit according to an embodiment of the present invention is a lens unit used in a display system that displays an image to a user, comprising: a reflecting unit 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, and includes a reflective polarizing element and an absorptive polarizing element disposed in front of the reflective polarizing element; a first lens unit that is disposed on an optical path between the display element and the reflecting unit; a half mirror that is disposed between the display element and the first lens unit, transmits the light emitted from the display element, and reflects the light reflected by the reflecting unit toward the reflecting unit; and a second λ/4 element that is disposed on an optical path between the half mirror and the reflecting unit, and the reflective axis transmittance is 0.5% or less when polarized light in the reflection axis direction of the reflective polarizing element is incident on a laminate of the reflective polarizing element and the absorptive polarizing element from the reflective polarizing element side.
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. The lens portion according to any one of 1 to 3 above may include a second lens portion disposed in front of the reflecting portion.
5. In the lens portion according to any one of 1 to 4 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°.

6. A laminate according to an embodiment of the present invention is used in the reflective portion of the lens unit according to any one of 1 to 5 above, and has the reflective polarizing member and the absorptive polarizing member.
7. In the laminate according to 6 above, the reflective polarizing member and the absorptive polarizing member may be laminated via an adhesive layer.
8. In the laminate according to 6 or 7 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. A display according to an embodiment of the present invention has a lens portion according to any one of 1 to 5 above.
10. 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.

11. 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 reflecting unit including a reflective polarizing element; making the light reflected by the reflecting unit and the half mirror transmittable through the reflective polarizing element of the reflecting unit by the second λ/4 element; and transmitting the light that has passed through the reflective polarizing element through an absorptive polarizing element, and the reflective axis transmittance is 0.5% or less when polarized light in the reflective axis direction of the reflective polarizing element is incident on the laminate of the reflective polarizing element and the absorptive polarizing element from the reflective polarizing element side.

The lens portion according to the embodiment of the present invention can achieve lighter weight and higher definition in VR goggles.

1 is a schematic diagram showing a general configuration of a display system according to an embodiment of the present invention. 2 is a schematic cross-sectional view showing an example of a laminate used in a reflector of the display system shown in FIG. 1 . 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 in-plane direction perpendicular to the slow axis (i.e., the fast axis direction), and "nz" is the refractive index in the thickness direction.
(2) In-plane 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°.

FIG. 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 reflecting section 14, a first lens section 16, a half mirror 18, a first phase difference member 20, a second phase difference member 22, and a second lens section 24. The reflecting section 14 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 section 16 is disposed on the optical path between the display element 12 and the reflecting section 14, and the half mirror 18 is disposed between the display element 12 and the first lens section 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 reflecting section 14.

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 reflecting section 14, 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 reflecting portion 14 toward the reflecting portion 14. The half mirror 18 is integrally provided with the first lens portion 16.

The second phase difference member 22 is a λ/4 member that can transmit the light reflected by the reflecting section 14 and the half mirror 18 through the reflecting section 14, which includes a reflective polarizing member (hereinafter, the second phase difference member may be referred to as a second λ/4 member). The second phase difference member 22 may be provided integrally with the first lens section 16.

The first circularly polarized light emitted from the first λ/4 member 20 passes through the half mirror 18 and the first lens unit 16, and is converted into the second linearly polarized light by the second 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 included in the reflecting unit 14. At this time, the polarization direction of the second linearly polarized light incident on the reflective polarizing member included in the reflecting unit 14 is the same as the reflection axis of the reflective polarizing member. Therefore, the second linearly polarized light incident on the reflecting unit is reflected by the reflective polarizing member.

The second linearly polarized light reflected by the reflecting unit 14 is converted into a second circularly polarized light by the second λ/4 member 22, and the second circularly polarized light emitted from the second λ/4 member 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 a third linearly polarized light by the second λ/4 member 22. The third linearly polarized light passes through the reflective polarizing member included in the reflecting unit 14. At this time, the polarization direction of the third linearly polarized light incident on the reflective polarizing member included in the reflecting unit 14 is the same as the transmission axis of the reflective polarizing member. Therefore, the third linearly polarized light incident on the reflecting unit 14 passes through the reflective polarizing member.

Light that passes through the reflecting portion 14 passes through the second lens portion 24 and enters the user's eye 26.

For example, the absorption axis of the polarizing member included in the display element 12 and the reflection axis of the reflective polarizing member included in the reflecting section 14 may be arranged substantially parallel to each other or substantially 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 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, 0.75 or more and less than 1, and may be 0.8 or more and 0.95 or less.

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, 0.75 or more and less than 1, and may be 0.8 or more and 0.95 or less.

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

Figure 2 is a schematic cross-sectional view showing an example of a laminate used in the reflector of the display system shown in Figure 1. The laminate 30 includes a reflective polarizing element 32 and an absorptive polarizing element 34, and the reflective polarizing element 32 and the absorptive polarizing element 34 are laminated via an adhesive layer 36. By using the adhesive layer, the reflective polarizing element 32 and the absorptive polarizing element 34 are fixed, and it is possible to prevent the axial arrangement of the reflection axis and the absorption axis (transmission axis and transmission axis) from being misaligned. In addition, it is possible to suppress the adverse effects of an air layer that may be formed between the reflective polarizing element 32 and the absorptive polarizing element 34. The adhesive layer 36 may be formed of an adhesive or a pressure-sensitive adhesive. The thickness of the adhesive layer 36 is, for example, 0.05 μm to 30 μm, preferably 3 μm to 20 μm, and more preferably 5 μm to 15 μm.

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 3 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 may typically include a resin film (sometimes referred to as an absorptive polarizing film) containing a dichroic material. 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.

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.

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, or the like. 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, as 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 by immersing the laminate in a liquid in a treatment process 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 it 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 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 the manufacturing method of such an absorptive polarizing film are described in, for example, JP 2012-73580 A and JP 6470455 A. The entire disclosures of these publications are incorporated herein by reference.

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 degree of polarization (P) of the absorptive polarizing element (absorptive polarizing film) is, for example, 99.0% to 99.997%, and preferably 99.9% or more.

The reflection axis transmittance of the reflective section (when polarized light in the reflection axis direction is incident on the reflective section) is preferably 0.5% or less, more preferably 0.1% or less, and even more preferably 0.05% or less. By satisfying such a reflection axis transmittance, it is possible to suppress the user's perception of afterimages (ghosts), and excellent display characteristics can be achieved.

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 of the reflecting portion can be achieved extremely well by combining a reflective polarizing element with an absorptive polarizing element.

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").

[Example 1-1]
(Preparation of Polarizing Film 1)
The thermoplastic resin substrate used was a long amorphous isophthalic copolymerized polyethylene terephthalate film (thickness: 100 μm) having a water absorption rate of 0.75% and a Tg of about 75° C. One side of the resin substrate was subjected to a corona treatment.
A PVA aqueous solution (coating solution) was prepared by adding 13 parts by weight of potassium iodide to 100 parts by weight of a PVA-based resin prepared by mixing polyvinyl alcohol (polymerization degree 4,200, saponification degree 99.2 mol%) and acetoacetyl-modified PVA (manufactured by Mitsubishi Chemical Corporation, product name "GOHSENEX Z410") in a ratio of 9:1, and dissolving the resultant in water.
The above PVA aqueous solution was applied to the corona-treated surface of a resin substrate and dried at 60° C. to form a PVA-based resin layer having a thickness of 13 μm, thereby producing a laminate.
The obtained laminate was uniaxially stretched at its free end to 2.4 times its original size in the machine direction (longitudinal direction) between rolls having different peripheral speeds in an oven at 130° C. (auxiliary 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 respect to 100 parts by weight of water) having a liquid temperature of 30° C. for 60 seconds while adjusting the concentration so that the single transmittance (Ts) of the finally obtained polarizing film would be 42.0% or more (dyeing treatment).
Next, the plate was immersed in a crosslinking bath (a boric acid aqueous solution obtained by mixing 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).
Thereafter, the laminate was immersed in an aqueous boric acid 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 (an 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, while drying in an oven maintained at 90° C., the laminate was brought into contact with a SUS heated roll having a surface temperature maintained at 75° C. for about 2 seconds (drying shrinkage treatment). The shrinkage rate of the laminate in the width direction due to the drying shrinkage treatment was 5.2%.
In this manner, a polarizing film 1 (absorption type polarizing film) having a thickness of 5 μm was formed on the resin substrate.

(Preparation of Absorptive Polarizing Film)
A cycloolefin resin film having a thickness of 25 μm was attached as a protective layer to the surface of the obtained absorptive polarizing film (the surface of the laminate on the polarizing film 1 side) via an ultraviolet-curing adhesive. Specifically, the adhesive was applied so that the thickness of the adhesive layer after curing was about 1 μm, and the layers were attached using a rolling machine. Thereafter, the adhesive was cured by irradiating it with UV light from the cycloolefin resin film side. Next, the resin substrate was peeled off to obtain an absorptive polarizing film having a cycloolefin resin film/absorptive polarizing film configuration.

(Preparation of film for reflective portion)
The absorptive polarizing film was bonded 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 absorptive polarizing film were arranged parallel to each other, thereby obtaining a film for the reflection portion (laminate film).

[Examples 1-2 and 1-3]
A film for a reflective portion was obtained in the same manner as in Example 1-1, except that in the preparation of the polarizing film 1, the dyeing treatment conditions were changed.

[Examples 1 to 4]
A polarizing film for a reflective portion was obtained in the same manner as in Example 1-1, except that the polarizing film 2 described below was used instead of the polarizing film 1.
(Preparation of Polarizing Film 2)
A long roll of a polyvinyl alcohol (PVA)-based resin film (manufactured by Kuraray, product name "PE3000") having a thickness of 30 μm was uniaxially stretched in the longitudinal direction to 5.9 times its original length using a roll stretching machine while simultaneously undergoing swelling, dyeing, crosslinking, and washing treatments in this order, and finally a drying treatment was performed to produce polarizing film 2 having a thickness of 12 μm.
The swelling treatment was performed by stretching the film 2.2 times while treating with pure water at 20°C. Next, the dyeing treatment was performed by stretching the film 1.4 times while treating it in an aqueous solution at 30°C in which the weight ratio of iodine to potassium iodide was 1:7, and the iodine concentration was adjusted so that the single transmittance of the resulting polarizing film was 42.0% or more. Next, the crosslinking treatment was performed in two stages, and the first stage was stretched 1.2 times while treating it in an aqueous solution at 40°C in which boric acid and potassium iodide were dissolved. The aqueous solution at the first stage had a boric acid content of 5.0% by weight and a potassium iodide content of 3.0% by weight. The second stage was stretched 1.6 times while treating it in an aqueous solution at 65°C in which boric acid and potassium iodide were dissolved. The aqueous solution at the second stage was stretched 1.6 times while treating it in an aqueous solution at 65°C in which boric acid and potassium iodide were dissolved. The aqueous solution at the second stage was stretched 4.3% by weight and a potassium iodide content of 5.0% by weight. Next, the film was washed with an aqueous potassium iodide solution at 20° C. The aqueous solution used for the washing treatment had a potassium iodide content of 2.6% by weight. Finally, the film was dried at 70° C. for 5 minutes to obtain a polarizing film 2.

[Examples 1 to 5]
A film for a reflective portion was obtained in the same manner as in Example 1-4, except that in the preparation of the polarizing film 2, the dyeing treatment conditions were changed.

[Examples 2-1 to 2-5]
A film for the reflective portion was obtained in the same manner as in Examples 1-1 to 1-5, except that "APCFG5" manufactured by Nitto Denko Corporation was used as the reflective polarizing film.

[Comparative Example 1]
As the film for the reflective portion, "APCFG4" manufactured by Nitto Denko Corporation (Ts measured by the method described below is 46.8% and P is 96.4%) was used.

[Comparative Example 2]
As the film for the reflective portion, "APCFG5" manufactured by Nitto Denko Corporation (Ts measured by the method described below is 47.0% and P is 93.1%) was used.

The following evaluations were carried out for the Examples and Comparative Examples. The evaluation results are summarized in Table 1.
<Evaluation>
Single transmittance and polarization degree The single transmittance Ts, parallel transmittance Tp, and crossed transmittance Tc of the absorptive polarizing film were measured using an ultraviolet-visible spectrophotometer (manufactured by Otsuka Electronics Co., Ltd., "LPF200"). 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.
From the obtained Tp and Tc, the degree of polarization P was calculated according to the following formula.
Polarization degree P (%) = {(Tp-Tc)/(Tp+Tc)} ^1/2 ×100
Reflection axis transmittance For the film for reflection, a UV-visible spectrophotometer (manufactured by Otsuka Electronics Co., Ltd., "LPF200") was used to measure the reflection axis transmittance by irradiating polarized light in the reflection axis direction of the reflective polarizing film contained in the film for reflection from the reflective polarizing film side.

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.

2 display system 4 lens portion 12 display element 14 reflecting portion 16 first lens portion 18 half mirror 20 first phase difference member 22 second phase difference member 24 second lens portion 30 laminate 32 reflective polarizing member 34 absorptive polarizing member 36 adhesive layer

Claims (10)

1. A lens unit for use in a display system for displaying an image to a user, comprising:
a reflecting section that reflects light that is emitted forward from a display surface of a display element that displays an image and that has passed through a polarizing member and a first λ/4 member, the reflecting section including a reflective polarizing member and an absorptive polarizing member that is disposed in front of the reflective polarizing member;
a first lens portion disposed on an optical path between the display element and the reflector;
a half mirror disposed between the display element and the first lens portion, the half mirror transmitting light emitted from the display element and reflecting the light reflected by the reflecting portion toward the reflecting portion;
a second λ/4 member disposed on an optical path between the half mirror and the reflecting portion,
a reflection axis transmittance of 0.5% or less when polarized light in the reflection axis direction of the reflective polarizing member is incident on a laminate of the reflective polarizing member and the absorptive polarizing member from the reflective polarizing member 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 lens unit according to claim 1, further comprising a second lens unit disposed in front of the reflecting unit. 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 unit according to any one of claims 1 to 5 is used in the reflecting portion of the lens unit,
The reflective polarizing member and the absorptive polarizing member are included.
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 the reflective polarizing member and the absorptive polarizing member are laminated via an adhesive layer. 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 reflecting section including a reflective polarizing member;
allowing the light reflected by the reflecting unit and the half mirror to pass through the reflective polarizing member of the reflecting unit by the second λ/4 member;
and transmitting the light transmitted through the reflective polarizing member through an absorptive polarizing member,
a reflection axis transmittance of 0.5% or less when polarized light in the reflection axis direction of the reflective polarizing member is incident on a laminate of the reflective polarizing member and the absorptive polarizing member from the reflective polarizing member side;
Display method.

Images