Display system, display method, display body, and method for manufacturing a display body
The display system optimizes light polarization and reflection paths using polarizing members and λ/4 members to address weight reduction and high definition challenges in VR goggles, achieving improved image quality and reduced weight.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- NITTO DENKO CORP
- Filing Date
- 2022-05-10
- Publication Date
- 2026-07-24
AI Technical Summary
Existing VR goggles face challenges in achieving both weight reduction and high definition, particularly in the development of optical members suitable for display systems using thin lenses.
A display system incorporating specific configurations of polarizing members, λ/4 members, and lenses, including reflective portions, half-mirrors, and phase difference members, optimized to achieve weight reduction and high definition by controlling light polarization and reflection paths.
The system achieves weight reduction and high definition in VR goggles by effectively managing light transmission and reflection, suppressing coloration, and enhancing image quality.
Smart Images

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Figure 0007894726000001
Abstract
Description
Technical Field
[0001] The present invention relates to a display system, a display method, a display body, and a method for manufacturing the display body.
Background Art
[0002] Image display devices typified by liquid crystal display devices and electroluminescence (EL) display devices (for example, organic EL display devices) have been rapidly spreading. In image display devices, in order to realize image display and improve the performance of image display, generally, optical members such as polarizing members and retardation members are used (for example, refer to Patent Document 1).
[0003] In recent years, new applications of image display devices have been developed. For example, goggles with a display (VR goggles) for realizing Virtual Reality (VR) have begun to be commercialized. Since VR goggles are being considered for use in various scenarios, weight reduction, high definition, etc. are desired. Weight reduction can be achieved, for example, by thinning the lenses used in VR goggles. On the other hand, the development of optical members suitable for a display system using thin lenses is also desired.
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0005] <00000%35>In view of the above, the main object of the present invention is to provide a display system that can achieve weight reduction and high definition of VR goggles.
Means for Solving the Problems
[0006] According to one aspect of the present invention, the following display systems [1] to [7] are provided. [1] A display system that displays images to a user, A display element having a display surface that emits light representing an image forward via a polarizing member, A reflective portion is positioned in front of the above-mentioned display element and includes a reflective polarizing member, which reflects light emitted from the above-mentioned display element. A first lens portion is arranged in the optical path between the above-mentioned display element and the above-mentioned reflective portion, A half-mirror is positioned between the display element and the first lens section, which transmits light emitted from the display element and reflects the light reflected by the reflecting section back towards the reflecting section. A first λ / 4 member is arranged in the optical path between the above-mentioned display element and the above-mentioned half-mirror, A second λ / 4 member is positioned in the optical path between the half-mirror and the reflecting part, Equipped with, A display system in which the first λ / 4 member and the second λ / 4 member satisfy Re(450) / Re(550) < 0.90, respectively. [2] The first λ / 4 member and the second λ / 4 member are, Re(400) / Re(550)<0.85, Re(650) / Re(550)>1.03, and Re(750) / Re(550)>1.05, A display system as described in [1] that satisfies the requirements. [3] The angle between the absorption axis of the polarization member included in the display element and the slow axis of the first λ / 4 member is 40° to 50°. The display system according to [1] or [2], wherein the angle between the absorption axis of the polarizing member included in the display element and the slow axis of the second λ / 4 member is 40° to 50°. [4] The display system according to any one of [1] to [3], wherein the first lens section and the half mirror are integrated. [5] A display system according to any one of [1] to [4], comprising a second lens portion positioned in front of the reflective portion. [6] The display system according to any one of [1] to [5], wherein the reflective portion includes an absorbing polarizing member positioned in front of the reflective polarizing member. [7] The display system according to [6], wherein the reflection axis of the reflective polarizing member and the absorption axis of the absorptive polarizing member are arranged parallel to each other.
[0007] According to another aspect of the present invention, the following display methods [8] to [9] are provided. [8] The step of passing the light representing the image emitted through the polarizing member through the first λ / 4 member, The steps include passing the light that has passed through the first λ / 4 member through the half mirror and the first lens section, The steps include passing the light that has passed through the above-mentioned half-mirror and the above-mentioned first lens portion through a second λ / 4 member, The steps include: reflecting the light that has passed through the second λ / 4 member toward the half mirror using a reflective section that includes a reflective polarizing member; The step includes making the light reflected by the above-mentioned reflective portion and the above-mentioned half-mirror passable through the above-mentioned reflective portion by the second λ / 4 member, A display method in which the first λ / 4 member and the second λ / 4 member satisfy Re(450) / Re(550) < 0.90, respectively. [9] The first λ / 4 member and the second λ / 4 member are, Re(400) / Re(550)<0.85, Re(650) / Re(550)>1.03, and Re(750) / Re(550)>1.05, The display method described in [8] that satisfies the requirements.
[0008] According to another aspect of the present invention, a display body comprising the display system described in any of [1] to [7] above is provided. In yet another aspect of the present invention, a method for manufacturing a display body comprising the display system described in any of [1] to [7] above is provided. [Effects of the Invention]
[0009] According to the display system according to an embodiment of the present invention, weight reduction and high definition of the VR goggles can be achieved.
Brief Description of Drawings
[0010] [Figure 1] It is a schematic diagram showing a schematic configuration of a display system according to an embodiment of the present invention.
Embodiments for Carrying Out the Invention
[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments. Also, for the purpose of making the description clearer, the drawings may schematically represent the width, thickness, shape, etc. of each part compared to the embodiments, but this is merely an example and does not limit the interpretation of the present invention.
[0012] (Definitions of Terms and Symbols) The definitions of terms and symbols in this specification are as follows. (1) Refractive Index (nx, ny, nz) “nx” is the refractive index in the direction where the in-plane refractive index is maximum (i.e., the slow axis direction), “ny” is the refractive index in the direction orthogonal 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 phase difference measured with light of wavelength λ nm at 23°C. For example, “Re(550)” is the in-plane phase difference measured with light of wavelength 550 nm at 23°C. Re(λ) is obtained by the formula: Re(λ) = (nx - ny) × d when the thickness of the layer (film) is d (nm). [[ID=z32]] (3) Phase Difference in the Thickness Direction (Rth) “Rth(λ)” is the phase difference in the thickness direction measured with light of wavelength λ nm at 23°C. For example, “Rth(550)” is the phase difference in the thickness direction measured with light of wavelength 55 o nm at 23°C. Rth(λ) is obtained by the formula: Rth(λ) = (nx - nz) × d when the thickness of the layer (film) is d (nm). (4) Nz coefficient The Nz coefficient is calculated using the formula Nz = Rth / Re. (5)Angle In this specification, when an angle is mentioned, unless otherwise specified, that angle includes both clockwise and counterclockwise directions with respect to the reference direction. Therefore, for example, "45°" means ±45°.
[0013] Figure 1 is a schematic diagram showing the general configuration of a display system according to one embodiment of the present invention. Figure 1 schematically illustrates the arrangement and shape of each component of the display system 2. The display system 2 comprises a display element 12, a reflector 14, a first lens 16, a half mirror 18, a first phase difference member 20, a second phase difference member 22, and a second lens 24. The reflector 14 is positioned in front of the display element 12 on the display surface 12a side and can reflect light emitted from the display element 12. The first lens 16 is positioned in the optical path between the display element 12 and the reflector 14, and the half mirror 18 is positioned between the display element 12 and the first lens 16. The first phase difference member 20 is positioned in the optical path between the display element 12 and the half mirror 18, and the second phase difference member 22 is positioned in the optical path between the half mirror 18 and the reflector 14.
[0014] The components positioned 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) are sometimes collectively referred to as the lens section (lens section 4).
[0015] 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. Light emitted from the display surface 12a passes through a polarizing member (typically a polarizing film) that may be included in the display element 12, and is emitted as first linearly polarized light.
[0016] The first phase difference member 20 is a λ / 4 member capable of converting a first linearly polarized light incident on the first phase difference member 20 into a 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.
[0017] The half-mirror 18 transmits light emitted from the display element 12 and reflects the light reflected by the reflecting part 14 back towards the reflecting part 14. The half-mirror 18 is integrally provided with the first lens part 16.
[0018] The second phase difference member 22 is a λ / 4 member that can transmit light reflected by the reflecting portion 14 and the half mirror 18 through the reflecting portion 14, which includes a reflective polarizing member (hereinafter, the second phase difference member may be referred to as the second λ / 4 member). The second phase difference member 22 may be provided integrally with the first lens portion 16.
[0019] 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 a 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 towards the half mirror 18 without passing through the reflective polarizing member included in the reflecting portion 14. At this time, the polarization direction of the second linearly polarized light incident on the reflective polarizing member included in the reflecting portion 14 is in the same direction as the reflection axis of the reflective polarizing member. Therefore, the second linearly polarized light incident on the reflecting portion is reflected by the reflective polarizing member.
[0020] The second linearly polarized light reflected by the reflecting section 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 section 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 section 16 and is converted into a third linearly polarized light by the second λ / 4 member 22. The third linearly polarized light is transmitted through the reflective polarizing member included in the reflecting section 14. At this time, the polarization direction of the third linearly polarized light incident on the reflective polarizing member included in the reflecting section 14 is in the same direction as the transmission axis of the reflective polarizing member. Therefore, the third linearly polarized light incident on the reflecting section 14 is transmitted through the reflective polarizing member.
[0021] Light that has passed through the reflective section 14 passes through the second lens section 24 and enters the user's eye 26.
[0022] 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 reflection section 14 can be arranged substantially parallel or substantially perpendicular to each other. The angle between the absorption axis of the polarizing member included in the display element 12 and the lagging 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 lagging axis of the second phase difference member 22 is, for example, 40° to 50°, may be 42° to 48°, or may be about 45°.
[0023] The in-plane phase difference Re(550) of the first phase difference member 20 is, for example, 100 nm to 190 nm, but may also be 110 nm to 180 nm, 130 nm to 160 nm, or 135 nm to 155 nm.
[0024] The first retardation member 20 preferably exhibits an inverse dispersion wavelength characteristic in which the retardation value increases according to the wavelength of the measurement light. Re(450) / Re(550) of the first retardation member 20 is, for example, less than 1, may be 0.95 or less, further may be less than 0.90, and even further may be 0.85 or less. Re(450) / Re(550) of the first retardation member 20 is, for example, 0.75 or more. By using the first retardation member exhibiting the inverse dispersion wavelength characteristic, coloring of the transmitted light can be suppressed.
[0025] In one embodiment, the first retardation 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 retardation 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. By using the first retardation member exhibiting the inverse dispersion wavelength characteristic over a wide wavelength range, coloring of the transmitted light can be more suitably suppressed.
[0026] The first retardation member 20 preferably exhibits a refractive index characteristic in which nx > ny ≧ nz. Here, "ny = nz" includes not only the case where ny and nz are exactly equal but also the case where they are substantially equal. Therefore, within a range that does not impair the effects of the present invention, ny < nz may occur. The Nz coefficient of the first retardation 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.
[0027] The first phase difference member 20 is formed from any suitable material that can satisfy the above characteristics. The first phase difference member 20 may be, for example, a stretched film of a resin film or an oriented solidified layer of a liquid crystal compound.
[0028] Examples of resins included in the above-mentioned resin film include polycarbonate resins, polyester carbonate resins, polyester resins, polyvinyl acetal resins, polyarylate resins, cyclic olefin resins, cellulose resins, polyvinyl alcohol resins, polyamide resins, polyimide resins, polyether resins, polystyrene resins, and acrylic resins. These resins may be used individually or in combination (e.g., blended, copolymerized). When the first phase difference member 20 exhibits inverse dispersion wavelength characteristics, a resin film containing a polycarbonate resin or a polyester carbonate resin (hereinafter sometimes simply referred to as a polycarbonate resin) can be suitably used.
[0029] As the polycarbonate resin described above, any suitable polycarbonate resin can be used as long as the effects of the present invention are obtained. For example, the polycarbonate resin includes structural units derived from fluorene-based dihydroxy compounds, structural units derived from isosorbide-based dihydroxy compounds, and structural units derived from at least one dihydroxy compound selected from the group consisting of alicyclic diols, alicyclic dimethanol, di, tri, or polyethylene glycol, and alkylene glycol or spiroglycol. Preferably, the polycarbonate resin includes structural units derived from fluorene-based dihydroxy compounds, structural units derived from isosorbide-based dihydroxy compounds, structural units derived from alicyclic dimethanol, and / or structural units derived from di, tri, or polyethylene glycol; more preferably, it includes structural units derived from fluorene-based dihydroxy compounds, structural units derived from isosorbide-based dihydroxy compounds, and structural units derived from di, tri, or polyethylene glycol. The polycarbonate resin may optionally include structural units derived from other dihydroxy compounds. Further details regarding polycarbonate resins suitably used for the first phase difference member and methods for forming the first phase difference member are described, for example, in Japanese Patent Publication No. 2014-10291, Japanese Patent Publication No. 2014-26266, Japanese Patent Publication No. 2015-212816, Japanese Patent Publication No. 2015-212817, and Japanese Patent Publication No. 2015-212818, and the descriptions in these publications are incorporated herein by reference.
[0030] The thickness of the first phase difference member 20, which is composed 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.
[0031] The orientation-solidified layer of the above-mentioned liquid crystal compound is a layer in which the liquid crystal compound is oriented in a predetermined direction within the layer, and this orientation state is fixed. Note that the term "orientation-solidified layer" is a concept that includes the orientation-cured layer obtained by curing liquid crystal monomers, as described later. In the first phase difference member, typically, rod-shaped liquid crystal compounds are oriented in a state where they are aligned in the slow phase axis direction of the first phase difference member (homogenous orientation). Examples of rod-shaped liquid crystal compounds include liquid crystal polymers and liquid crystal monomers. Preferably, the liquid crystal compound is polymerizable. If the liquid crystal compound is polymerizable, the orientation state of the liquid crystal compound can be fixed by polymerizing it after orientation.
[0032] The above-mentioned oriented solidified layer of liquid crystal compound (liquid crystal oriented solidified layer) can be formed by applying an orientation treatment to the surface of a predetermined substrate, coating the surface with a coating liquid containing the liquid crystal compound to orient the liquid crystal compound in the direction corresponding to the orientation treatment, and fixing the orientation state. Any appropriate orientation treatment can be used as the orientation treatment. Specifically, these include mechanical orientation treatment, physical orientation treatment, and chemical orientation treatment. Specific examples of mechanical orientation treatment include rubbing treatment and stretching treatment. Specific examples of physical orientation treatment include magnetic field orientation treatment and electric field orientation treatment. Specific examples of chemical orientation treatment include oblique deposition and photo-orientation treatment. Any appropriate conditions can be adopted for each orientation treatment depending on the purpose.
[0033] The orientation of liquid crystal compounds is achieved by treating them at a temperature that exhibits the liquid crystal phase, depending on the type of liquid crystal compound. This temperature treatment causes the liquid crystal compound to enter a liquid crystal state, and it then orients according to the orientation treatment direction on the substrate surface.
[0034] In one embodiment, the orientation state is fixed by cooling the liquid crystal compound oriented as described above. If the liquid crystal compound is polymerizable or crosslinkable, the orientation state is fixed by subjecting the liquid crystal compound oriented as described above to a polymerization treatment or a crosslinking treatment.
[0035] As the above-mentioned liquid crystal compound, any suitable liquid crystal polymer and / or liquid crystal monomer can be used. The liquid crystal polymer and liquid crystal monomer may be used individually or in combination. Specific examples of liquid crystal compounds and methods for producing liquid crystal alignment solidified layers are described, for example, in Japanese Patent Publication No. 2006-163343, Japanese Patent Publication No. 2006-178389, and International Publication No. 2018 / 123551. The descriptions in these publications are incorporated herein by reference.
[0036] The thickness of the first phase difference member 20, which is composed of a liquid crystal alignment solidification 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.
[0037] The in-plane phase difference Re(550) of the second phase difference member 22 is, for example, 100 nm to 190 nm, but may also be 110 nm to 180 nm, 130 nm to 160 nm, or 135 nm to 155 nm.
[0038] The second phase difference member 22 preferably exhibits inverse dispersion wavelength characteristics in which the phase difference value increases with the wavelength of the measured light. The Re(450) / Re(550) of the second phase difference member 22 is, for example, less than 1, may be 0.95 or less, and 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. By using a second phase difference member exhibiting inverse dispersion wavelength characteristics, coloration of the transmitted light can be suppressed.
[0039] In one embodiment, the second retardation 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 retardation 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. By using a second retardation member exhibiting inverse dispersion wavelength characteristics over a wide wavelength range, coloring of transmitted light can be more suitably suppressed.
[0040] The second retardation member 22 preferably exhibits a refractive index characteristic of nx>ny≧nz. Here, "ny=nz" includes not only the case where ny and nz are exactly equal but also the case where they are substantially equal. Therefore, within a range that does not impair the effects of the present invention, ny<nz may occur. The Nz coefficient of the second retardation 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.
[0041] The second retardation member 22 is formed of any suitable material that can satisfy the above characteristics. The second retardation member 22 can be, for example, a stretched film of a resin film or an orientation-solidified layer of a liquid crystal compound. Regarding the second retardation member 22 composed of a stretched film of a resin film or an orientation-solidified layer of a liquid crystal compound, the same description as that of the first retardation member 20 can be applied. The first retardation member 20 and the second retardation member 22 may be members having the same configuration (forming material, thickness, optical characteristics, etc.) or members having different configurations.
[0042] The reflective portion 14 may include an absorptive polarizing member (typically, an absorptive polarizing film). In this case, the absorptive polarizing member may be positioned 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 positioned substantially parallel to each other. For example, the reflective polarizing member and the absorptive polarizing member may be laminated with an adhesive layer in between, and the reflective portion 14 may include a laminate having the reflective polarizing member and the absorptive polarizing member. [Examples]
[0043] The present invention will be specifically described below with reference to examples, but the present invention is not limited in any way to these examples. The test and evaluation methods in the examples are as follows. When "parts" is written, it means "parts by weight" unless otherwise specified, and when "%" is written, it means "percent by weight" unless otherwise specified.
[0044] (1) Thickness Thicknesses of 10 μm or less were measured using a scanning electron microscope (JEOL Ltd., product name "JSM-7100F"). Thicknesses exceeding 10 μm were measured using a digital micrometer (Anritsu Corporation, product name "KC-351C"). (2) In-plane phase difference Re(λ) Samples were prepared by cutting out the center and both ends of a λ / 4 member in the width direction into squares measuring 50 mm in width and 50 mm in length, with one side parallel to the width direction of the member. The in-plane phase difference at each wavelength at 23°C was measured using a Müller matrix polarimeter (Axometrics, product name "Axoscan"). (3) Transmittance and polarization of a single unit The single-layer transmittance Ts, parallel transmittance Tp, and orthogonal transmittance Tc of polarizing films or laminates were measured using a spectrophotometer (Otsuka Electronics Co., Ltd., "LPF-200"). These Ts, Tp, and Tc values are Y values obtained by measuring under a 2-degree field of view (C light source) according to JIS Z8701 and correcting for luminous sensitivity. From the obtained Tp and Tc values, the polarization degree of the polarizing film was determined using the following formula. Degree of polarization (%)={(Tp-Tc) / (Tp+Tc)}1 / 2 ×100 (4) Hue Polarized light from a light source is incident on the λ / 4 member side surface of the laminates prepared in the examples and comparative examples, and the orthogonal hue (orthogonal a) of the light emitted from the polarizing film side surface is determined. * Value, orthogonal b * The value was measured using a spectrophotometer (Otsuka Electronics Co., Ltd., "LPF-200"). When viewed from the light source side, the slow axis direction of the λ / 4 component was at a 45° clockwise angle with respect to the absorption axis direction of the polarizing film (essentially the polarizing film within the polarizing film).
[0045] [Manufacturing Example 1: Fabrication of λ / 4 component A] A batch polymerization apparatus consisting of two vertical reactors equipped with stirring blades and reflux condensers controlled to 100°C was used to prepare the reactor. The mixture contained 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 × 10⁻¹⁶ calcium acetate monohydrate as a catalyst. -2 Weight part (6.78×10 -5A mol (mol) of polymer was added. After purging the reactor with reduced pressure using nitrogen, the reactor was heated with a heat transfer medium, and stirring was started when the internal temperature reached 100°C. Forty minutes after the start of heating, the internal temperature was raised to 220°C, and while controlling the pressure to maintain this temperature, the pressure was reduced to 13.3 kPa 90 minutes after reaching 220°C. The phenol vapor produced as a by-product of the polymerization reaction was directed to a reflux condenser at 100°C, and the monomer components contained in the phenol vapor were returned to the reactor. The uncondensed phenol vapor was directed to a condenser at 45°C and recovered. Nitrogen was introduced into the first reactor to restore the pressure to atmospheric pressure, and then the oligomerized reaction mixture in the first reactor was transferred to the second reactor. Next, heating and depressurization in the second reactor were started, and the internal temperature reached 240°C and the pressure 0.2 kPa in 50 minutes. Polymerization was then allowed to proceed until the predetermined stirring power was reached. Once the predetermined power level was reached, nitrogen was introduced into the reactor to restore pressure, and the resulting polyester carbonate resin was extruded into water. The strands were then cut to obtain pellets. The obtained polyester carbonate resin (pellets) was vacuum-dried at 80°C for 5 hours. Then, a long resin film with a thickness of 130 μm was produced using a film-making apparatus equipped with a single-screw extruder (manufactured by Toshiba Machine Co., Ltd., cylinder setting temperature: 250°C), a T-die (width 200 mm, setting temperature: 250°C), a chill roll (setting temperature: 120~130°C), and a winding machine. 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. This yielded a phase difference film (λ / 4 member A) with a thickness of 47 μm, a Re(590) of 143 nm, and an Nz coefficient of 1.2.
[0046] [Manufacturing Example 2: Fabrication of λ / 4 component B] A norbornene-based film (manufactured by Zeon Corporation, trade name "Zeonor", thickness 100 μm) exhibiting flat dispersion wavelength characteristics was stretched at a fixed end in the width direction at a stretching ratio of 3 times at a stretching temperature of 130°C to obtain a phase difference film (λ / 4 member B) with a thickness of 30 μm, a Re(590) of 140 nm, and an Nz coefficient of 1.6.
[0047] [Manufacturing Example 3: Production of Polarizing Film] As a thermoplastic resin substrate, an amorphous isophthalic copolymer polyethylene terephthalate film (thickness: 100 μm) in a long length with a Tg of approximately 75°C was used, and one side of the resin substrate was subjected to corona treatment. A PVA aqueous solution (coating solution) was prepared by dissolving 100 parts by weight of a PVA-based resin, which was prepared by mixing polyvinyl alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) and acetoacetyl-modified PVA (manufactured by Mitsubishi Chemical Corporation, trade name "Gosenex Z410") in a 9:1 ratio, with 13 parts by weight of potassium iodide. A PVA aqueous solution was applied to the corona-treated surface of a resin substrate and dried at 60°C to form a 13 μm thick PVA-based resin layer, thereby creating a laminate. The resulting laminate was uniaxially stretched 2.4 times in the longitudinal direction (longitudinal direction) in an oven at 130°C (air-assisted stretching). Next, the laminate was immersed for 30 seconds in an insolubilization bath at a liquid temperature of 40°C (a boric acid aqueous solution obtained by mixing 4 parts by weight of boric acid with 100 parts by weight of water) (insolubilization treatment). Next, the film was immersed for 60 seconds in a staining bath at 30°C (an iodine aqueous solution obtained by mixing iodine and potassium iodide in a weight ratio of 1:7 with 100 parts by weight of water) while adjusting the concentration so that the transmittance (Ts) of the final absorption polarizing film would be the desired value (staining treatment). Next, the material was immersed for 30 seconds in a crosslinking bath at a liquid temperature of 40°C (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) (crosslinking treatment). Subsequently, the laminate was immersed in a boric acid aqueous solution (boric acid concentration 4% by weight, potassium iodide concentration 5% by weight) at a liquid temperature of 70°C, and uniaxially stretched in the longitudinal direction (longitudinal direction) between rolls with different peripheral speeds to achieve a total stretch ratio of 5.5 times (underwater stretching treatment). Subsequently, the laminate was immersed in a washing bath at a liquid temperature of 20°C (an aqueous solution obtained by mixing 4 parts by weight of potassium iodide with 100 parts by weight of water) (washing treatment). Subsequently, the laminate was dried in an oven maintained at approximately 90°C while being brought into contact with a SUS (stainless steel) heated roll whose surface temperature was maintained at approximately 75°C (drying shrinkage treatment). The shrinkage rate in the width direction of the laminate due to the drying shrinkage treatment was 5.2%. In this way, an absorption-type polarizing film with a thickness of approximately 5 μm was formed on a resin substrate. A cycloolefin resin film (thickness: 25 μm) was bonded to the surface of the obtained absorption polarizing film (the side opposite to the resin substrate) via an ultraviolet-curing adhesive. Specifically, the curing adhesive was applied to a total thickness of approximately 1 μm and bonded using a roll press. Then, UV light was irradiated from the cycloolefin resin film side to cure the adhesive. Next, the resin substrate was peeled off. This resulted in a polarizing film having a cycloolefin resin film / absorption polarizing film structure. The transmittance (Ts) of the polarizing film alone was 43.4%, and the degree of polarization was 99.993%, orthogonal a * The value is 0.1, orthogonal b * The value was -0.1.
[0048] [Example 1] Laminate 1 was fabricated by laminating four λ / 4 component A on one side of the polarizing film obtained in Manufacturing Example 3. The lamination of each component was performed by bonding them together via an acrylic adhesive layer (manufactured by Nitto Denko Corporation, 5 μm thick). At this time, the slow axis directions of the four λ / 4 component A were parallel to each other, and the components were laminated at an angle of 45° counterclockwise with respect to the absorption axis direction (0°) of the absorbing polarizing film as viewed from the polarizing film side.
[0049] [Comparative Example 1] Laminate C1 was fabricated by laminating four λ / 4 members B onto the protective layer side surface of the polarizing film obtained in Manufacturing Example 3, in the same manner as in Example 1, except that λ / 4 member B was used instead of λ / 4 member A.
[0050] Table 1 shows the measurement results of the individual transmittance and hue of the laminates obtained in the above examples and comparative examples, along with the optical properties of the λ / 4 members. The laminates prepared in the examples and comparative examples are simplified evaluation models of the display system according to embodiments of the present invention. Specifically, the hue of light incident on the λ / 4 member side of the laminate and emitted from the polarizing film side can be evaluated as the hue of the light emitted forward after linearly polarized light emitted forward from the display surface of the display element has passed through the first phase difference member and the second phase difference member in that order, then passed through the second phase difference member two more times due to reflection at the reflective part and re-reflection at the half mirror, and then passed through the reflective part and emitted forward. [Table 1]
[0051] As shown in Table 1, by using λ / 4 members exhibiting inverse dispersion wavelength characteristics over a wide wavelength range as the first and second phase difference members, a neutral hue with suppressed coloration was obtained even when the light was transmitted through the two λ / 4 members a total of four times.
[0052] The present invention is not limited to the embodiments described above, and various modifications are possible. For example, the configurations shown in the embodiments above can be replaced with configurations that are substantially the same, configurations that produce the same effects, or configurations that can achieve the same purpose. [Industrial applicability]
[0053] The display system according to an embodiment of the present invention can be used, for example, in a display device such as VR goggles. [Explanation of symbols]
[0054] 2 Display System 4. Lens section 12 Display elements 14 Reflector 16 First lens section 18 Half Mirror 20 First phase difference member 22 Second phase difference member 24 Second lens section
Claims
1. A display system that displays images to the user, A display element having a display surface that emits light representing an image forward via a polarizing member, Displaced in front of the display element, and including a reflective polarizing member, a reflective portion that reflects light emitted from the display element, A first lens portion is arranged in the optical path between the display element and the reflecting portion, A half-mirror is disposed between the display element and the first lens portion, which transmits light emitted from the display element and reflects the light reflected by the reflecting portion toward the reflecting portion, A first λ / 4 member is arranged in the optical path between the display element and the half mirror, A second λ / 4 member is positioned in the optical path between the half mirror and the reflecting portion, Equipped with, The first λ / 4 member and the second λ / 4 member are, Re(450) / Re(550)<0.90, 1.03 < Re(650) / Re(550) < 1.20, and 1.05<Re(750) / Re(550)<1.36 Satisfying the conditions, The angle between the absorption axis of the polarizing member included in the display element and the lagging axis of the first λ / 4 member is 40° to 50°. A display system in which the angle between the absorption axis of the polarizing member included in the display element and the lagging axis of the second λ / 4 member is 40° to 50°.
2. The display system according to claim 1, wherein the first λ / 4 member and the second λ / 4 member each satisfy Re(400) / Re(550) < 0.
85.
3. The display system according to claim 1, wherein the first lens portion and the half mirror are integrated.
4. The display system according to claim 1, further comprising a second lens portion positioned in front of the reflective portion.
5. The display system according to claim 1, wherein the reflective portion includes an absorbing polarizing member disposed in front of the reflective polarizing member.
6. The display system according to claim 5, wherein the reflection axis of the reflective polarizing member and the absorption axis of the absorptive polarizing member are arranged parallel to each other.
7. The steps include passing light representing an image emitted through a polarizing member through a first λ / 4 member, The steps include: passing the light that has passed through the first λ / 4 member through the half mirror and the first lens section; The steps include: passing the light that has passed through the half mirror and the first lens portion through the second λ / 4 member; The steps include: reflecting the light that has passed through the second λ / 4 member toward the half mirror using a reflective section that includes a reflective polarizing member; The step of making the light reflected by the reflecting portion and the half-mirror passable through the reflecting portion by the second λ / 4 member, The first λ / 4 member and the second λ / 4 member are, Re(450) / Re(550)<0.90, 1.03 < Re(650) / Re(550) < 1.20, and 1.05<Re(750) / Re(550)<1.36 Satisfying the conditions, The angle between the absorption axis of the polarization member and the slow axis of the first λ / 4 member is 40° to 50°. A method of display in which the angle between the absorption axis of the polarizing member and the slow axis of the second λ / 4 member is 40° to 50°.
8. The display method according to claim 7, wherein the first λ / 4 member and the second λ / 4 member each satisfy Re(400) / Re(550) < 0.
85.
9. A display body comprising the display system described in any one of claims 1 to 6.
Citation Information
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