JP2024122667A - Display system, display method, display body, and method for manufacturing display body - Google Patents

Abstract

To provide a display system that can achieve reduction in weight and improvement in the definition of a VR goggle.SOLUTION: A display system according to an embodiment of the present invention displays an image for a user, and the display system comprises: a display device having a display surface emitting light showing an image frontward through a polarization member; a reflection part arranged in front of the display device, including a reflection type polarization member, and reflecting light emitted from the display device; a first lens part arranged on an optical path between the display device and the reflection part; a semitransparent mirror arranged between the display device and the first lens part, transmitting light emitted from the display device, and reflecting light reflected by the reflection part toward the reflection part; a first λ/4 member arranged on an optical path between the display device and the semitransparent mirror; and a second λ/4 member arranged on an optical path between the semitransparent mirror and the reflection part. Ellipticity of polarized light transmitted through the reflection part is 0.015 or less.SELECTED DRAWING: Figure 1

Description

The present invention relates to a display system, a display method, a display body, and a method for manufacturing a display body.

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 display system that can realize lightweight, high-definition VR goggles.

1. A display system according to an embodiment of the present invention is a display system that displays an image to a user, comprising: a display element having a display surface that emits light representing an image forward through a polarizing member; a reflecting section that is disposed in front of the display element and includes a reflective polarizing member and reflects the light emitted from the display element; a first lens section that is disposed on an optical path between the display element and the reflecting section; a half mirror that is disposed between the display element and the first lens section, transmits the light emitted from the display element, and reflects the light reflected by the reflecting section toward the reflecting section; a first λ/4 member that is disposed on an optical path between the display element and the half mirror; and a second λ/4 member that is disposed on an optical path between the half mirror and the reflecting section, and the ellipticity of the polarized light that transmits the reflecting section is 0.015 or less.
2. In the display system described in 1 above, a space may be formed between the first λ/4 member and the second λ/4 member.
3. In the display system described in 1 or 2 above, the display element and the first λ/4 member may be integrated together.
4. In the display system described in any one of 1 to 3 above, the first lens portion and the second λ/4 member may be integral with each other.
5. In the display system according to any one of the above items 1 to 4, an absolute value of a difference between an in-plane retardation (a) of the first λ/4 component and an in-plane retardation (b) of the second λ/4 component may be 3.5 nm or less.
6. In the display system according to any one of 1 to 5 above, the first λ/4 member and the second λ/4 member may be disposed such that an angle between the slow axis of the first λ/4 member and the slow axis of the second λ/4 member is 7° or less or 83° to 97°.
7. In the display system according to any one of 1 to 6 above, the first λ/4 member and the second λ/4 member may each have an ISC value of 50 or less.
8. In the display system described in any one of 1 to 7 above, the first λ/4 member and the second λ/4 member may each have a thickness of 100 μm or less.
9. In the display system described in any one of 1 to 8 above, the first λ/4 member and the second λ/4 member may each have a thickness variation of 1 μm or less.
10. In the display system described in any one of 1 to 9 above, the first λ/4 member and the second λ/4 member may each have an ISC value per unit thickness of 1 or less.
11. In the display system according to any one of 1 to 10 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°.

12. A display according to an embodiment of the present invention includes the display system according to any one of 1 to 11 above.
13. A method for manufacturing a display according to an embodiment of the present invention is a method for manufacturing a display including the display system according to any one of 1 to 11 above.

14. A display method according to an embodiment of the present invention includes the steps of: passing light representing an image emitted through a polarizing member through a first λ/4 member; passing the light that has passed through the first λ/4 member 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 member; reflecting the light that has passed through the second λ/4 member toward the half mirror with a reflecting unit including a reflective polarizing member; and allowing the light reflected by the reflecting unit and the half mirror to pass through the reflecting unit with the second λ/4 member, wherein the ellipticity of the polarized light that passes through the reflecting unit is 0.015 or less.

The display system according to an embodiment of the present invention can achieve lightweight, high-definition VR goggles.

1 is a schematic diagram showing a general configuration of a display system according to an embodiment of the present invention. 2A is a schematic diagram illustrating an example of the propagation of light in the display system shown in FIG. 1 , and FIG. 2B is a schematic diagram illustrating an example of a change in the polarization state of light in the display system shown in FIG. 1 . 1A is a schematic diagram illustrating another example of the propagation of light in the display system shown in FIG. 1 , and FIG. 1B is a schematic diagram illustrating another example of the change in the polarization state of light in the display system shown in FIG. 1 . FIG. 13 is a diagram for explaining a method for measuring the thickness variation. FIG. 2 is a diagram for explaining a method for measuring an ISC value.

Below, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments. In order to 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. In addition, in the drawings, the same or equivalent elements are given the same reference numerals, and duplicate descriptions may be omitted.

(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 an angle is mentioned in this specification, unless otherwise specified, the angle includes both clockwise and counterclockwise with respect to the reference direction. Therefore, for example, "45°" means ±45°. In addition, in this specification, "substantially parallel" includes the range of 0°±10°, preferably within the range of 0°±5°, more preferably within the range of 0°±3°, and even more preferably within the range of 0°±1°. "Substantially perpendicular" includes the range of 90°±10°, preferably within the range of 90°±5°, more preferably within the range of 90°±3°, and even more preferably within the range of 90°±1°.

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 including a reflective polarizing member, 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 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 14 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 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.

The ellipticity of the polarized light (specifically, the above-mentioned third linearly polarized light) transmitted through the reflecting portion 14 is 0.015 or less, preferably 0.013 or less, and more preferably 0.011 or less. Such an ellipticity can, for example, suppress light leakage and contribute to high definition. It can also suppress light loss and contribute to low power consumption and light weight of the display. The ellipticity is the ratio of the minor axis/major axis of the circularly polarized light; for example, the ellipticity is 1 for completely circularly polarized light, and the ellipticity is 0 for completely linearly polarized light. In one embodiment, the ellipticity is measured at a wavelength of 550 nm, where luminosity is high (for example, where the human eye is easily able to recognize light).

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, 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 ISC value of the first phase difference member 20 is, for example, 50 or less, preferably 40 or less, more preferably 30 or less, and even more preferably 20 or less. When the first phase difference member 20 satisfies such an ISC value, a display system with excellent visibility can be realized. For example, when such an ISC value is satisfied, the uniformity of the in-plane phase difference can be improved, and as a result, light leakage in the reflective portion described below can be suppressed. The ISC value can be an index of smoothness or unevenness.

The thickness variation of the first phase difference member 20 is preferably 1 μm or less, more preferably 0.8 μm or less, even more preferably 0.6 μm or less, and even more preferably 0.4 μm or less. With such thickness variation, for example, the above-mentioned ISC value can be achieved satisfactorily. Here, the thickness variation can be determined by measuring the thickness of a first portion located within the plane of the phase difference member, and the thickness of a position spaced a predetermined distance (e.g., 5 mm to 15 mm) from the first portion in any direction (e.g., upward, downward, leftward, and rightward).

The ISC value per unit thickness of the first phase difference member 20 is preferably 1 or less, more preferably 0.7 or less, and even more preferably 0.5 or less. The ISC value per unit thickness can be determined, for example, by dividing the ISC value by the thickness (unit: μm).

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 solidified layer of a liquid crystal compound. Note that a stretched resin film may be referred to as a phase difference film.

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 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 assume 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 is preferably 100 μm or less. Specifically, the thickness of the first phase difference member 20 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 60 μm, and even more preferably 20 μm to 50 μm. The thickness of the first phase difference member 20 made 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 even be less than 0.90 or 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 ISC value of the second phase difference member 22 is, for example, 50 or less, preferably 40 or less, more preferably 30 or less, and even more preferably 20 or less. When the second phase difference member 22 satisfies such an ISC value, a display system with excellent visibility can be realized. For example, when such an ISC value is satisfied, the uniformity of the in-plane phase difference can be improved, and as a result, light leakage in the reflective portion described below can be suppressed. The ISC value can be an index of smoothness or unevenness.

The variation in thickness of the second phase difference member 22 is preferably 1 μm or less, more preferably 0.8 μm or less, even more preferably 0.6 μm or less, and even more preferably 0.4 μm or less. With such a variation in thickness, for example, the above ISC value can be satisfactorily achieved.

The ISC value per unit thickness of the second phase difference member 22 is preferably 1 or less, more preferably 0.7 or less, and even more preferably 0.5 or less.

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 thickness of the second phase difference member 22 is preferably 100 μm or less. Specifically, the thickness of the second phase difference member 22 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 60 μm, and even more preferably 20 μm to 50 μm. The thickness of the second phase difference member 22 made 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 ellipticity of the polarized light transmitted through the reflecting portion 14 can be evaluated, for example, as the ellipticity of a laminate of a polarizing member that may be included in the display element 12, a first phase difference member 20, and three second phase difference members 22. Details of the laminate will be described later.

On the other hand, in the display system 2, a space may be formed between the first phase difference member 20 and the second phase difference member 22. Specifically, the first phase difference member 20 and the second phase difference member 22 are not integrated using an adhesive and/or a pressure sensitive adhesive, and a space may be formed between the first phase difference member 20 and the second phase difference member 22. Because of the space, for example, it may be difficult to align the slow axis of the first phase difference member 20 with the slow axis of the second phase difference member 22. In one embodiment, managing the ellipticity in the display system 2 can greatly contribute to high definition and improved visibility.

The above ellipticity can be achieved, for example, by adjusting the difference between the in-plane phase difference (a) of the first phase difference member and the in-plane phase difference (b) of the second phase difference member. The absolute value of the difference between the in-plane phase difference (a) of the first phase difference member and the in-plane phase difference (b) of the second phase difference member is, for example, 3.5 nm or less, preferably 3.0 nm or less, more preferably 2.5 nm or less, even more preferably 2.0 nm or less, particularly preferably 1.5 nm or less, and most preferably 1.0 nm or less. In one embodiment, (a) and (b) are values of Re(590).

It is preferable that the in-plane retardation (a) of the first retardation member and the in-plane retardation (b) of the second retardation member satisfy the following formula (I).
((a)-(b))/((a)+(b)/2)≦0.02...(I)
More preferably, ((a)-(b))/((a)+(b)/2)≦0.015, and even more preferably, ((a)-(b))/((a)+(b)/2)≦0.01.

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.

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 polarized in other states. The orthogonal transmittance (Tc) of the reflective polarizing element can be, for example, 0.01% to 3%. The single transmittance (Ts) of the reflective polarizing element can be, for example, 43% to 49%, preferably 45% to 47%. The polarization degree (P) of the reflective polarizing element can be, for example, 92% to 99.99%. The reflective polarizing element is typically composed of a film (sometimes referred to as a reflective polarizing film) having a multilayer structure. Commercially available reflective polarizing films include, for example, 3M products under the trade names "DBEF" and "APF" and Nitto Denko Corporation's product name "APCF".

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, 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 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.

2 is a schematic diagram for explaining an example of the progression of light and the change in the polarization state in the display system shown in FIG. 1. Specifically, FIG. 2(a) is a schematic diagram for explaining an example of the progression of light in the display system, and FIG. 2(b) is a schematic diagram for explaining an example of the change in the polarization state of light due to transmission through or reflection by each member in the display system. In FIG. 2, the solid arrows attached to the display element 12 indicate the absorption axis direction of the polarizing member included in the display element 12, the arrows attached to the first phase difference member 20 and the second phase difference member 22 indicate the slow axis direction, the solid arrows attached to the reflective polarizing member 14a included in the reflecting section 14 indicate the reflection axis direction, and the dashed arrows indicate the transmission axis direction of each polarizing member. In the illustrated example, the first phase difference member 20 and the second phase difference member 22 are arranged so that their slow axes are approximately parallel to each other. The absorption axis of the polarizing member included in the display element 12 and the reflection axis of the reflective polarizing member 14a included in the reflecting section 14 are arranged so that they are approximately parallel to each other. In other words, the polarization direction of the light emitted through the polarizing member included in the display element 12 and the reflection axis of the reflective polarizing member 14a included in the reflecting section 14 are approximately perpendicular to each other.

The light L emitted from the display element 12 as a first linearly polarized light through the polarizing member is converted into a first circularly polarized light by the first λ/4 member 20. The first circularly polarized light passes through the half mirror 18 and the first lens unit 16 (not shown in FIG. 2), and is converted into a second linearly polarized light having a polarization direction perpendicular to that of the first linearly polarized light by the second λ/4 member 22. The polarization direction of the second linearly polarized light is the same direction (approximately parallel) as the reflection axis of the reflective polarizing member 14a included in the reflecting unit 14. Therefore, the second linearly polarized light incident on the reflecting unit 14 is reflected by the reflective polarizing member 14a toward the half mirror 18.

The second linearly polarized light reflected by the reflecting portion 14 is converted into a second circularly polarized light by the second λ/4 member 22. The rotation direction of the second circularly polarized light is the same as the rotation direction of the first circularly polarized light. The second circularly polarized light emitted from the second λ/4 member 22 passes through the first lens portion 16 and is reflected by the half mirror 18, and is converted into a third circularly polarized light that rotates in the opposite direction to the second circularly polarized light. The third circularly polarized light reflected by the half mirror 18 passes through the first lens portion 16 and is converted into a third linearly polarized light by the second λ/4 member 22. The polarization direction of the third linearly polarized light is perpendicular to the polarization direction of the second linearly polarized light and is in the same direction (approximately parallel) as the transmission axis of the reflective polarizing member 14a. Therefore, the third linearly polarized light can be transmitted through the reflective polarizing member 14a. In addition, although not shown, when the reflecting section includes an absorptive polarizing member, the absorption axis of the absorptive polarizing member is arranged to be approximately parallel to the reflection axis of the reflective polarizing member 14a, so that the third linearly polarized light that has passed through the reflective polarizing member 14a can pass through the absorptive polarizing member as is. The light that has passed through the reflecting section 14 passes through the second lens section 24 and enters the user's eye 26.

As described above, in the display system according to the embodiment of the present invention, the first linearly polarized light emitted from the display element 12 through the polarizing member can be converted into the first circularly polarized light by the first λ/4 member 20, converted into the second linearly polarized light by the second λ/4 member 22, and reflected by the reflecting unit 14. The second linearly polarized light can then be converted into the second circularly polarized light by the second λ/4 member 22, reflected by the half mirror 18, converted into the third linearly polarized light by the second λ/4 member 22, and transmitted through the reflecting unit 14. Here, by setting the ellipticity of the polarized light transmitted through the reflecting unit 14 to 0.015 or less, light leakage in the reflecting unit 14 can be suppressed extremely well, and as a result, light that should be reflected or absorbed by the reflecting unit 14 can be suitably suppressed from being viewed by the user as an afterimage (ghost). In addition, the reflecting unit 14 can suppress light loss (for example, the generation of a polarized component in the reflection axis direction). In a display system 2 that uses many components, the light utilization efficiency is low (for example, about 10%) and the amount of light required can be large. Therefore, the effect of suppressing light loss can be significantly achieved. Specifically, this can greatly contribute to reducing power consumption and the weight of the display body.

In the example shown in FIG. 2, when viewed from the display element 12 side, the slow axes of the first phase difference member 20 and the second phase difference member 22 are both arranged to form a predetermined angle (e.g., 40° to 50°) counterclockwise with respect to the absorption axis of the polarizing member included in the display element 12, but they may be arranged to form a predetermined angle (e.g., 40° to 50°) clockwise. In this case, the same explanation as above can be applied. The first phase difference member 20 and the second phase difference member 22 are arranged so that the angle between their respective slow axes is, for example, 7° or less, preferably 6° or less, more preferably 5° or less, even more preferably 4° or less, and even more preferably 3° or less. The slow axis of the first phase difference member 20 and the slow axis of the second phase difference member 22 satisfy such a relationship, and thus the above ellipticity can be satisfactorily achieved.

In the example shown in FIG. 2, the slow axis of the first phase difference member 20 and the slow axis of the second phase difference member 22 are arranged approximately parallel to each other, but they may be arranged approximately perpendicular to each other as shown in FIG. 3. For example, one of the slow axis of the first phase difference member 20 and the slow axis of the second phase difference member 22 may be arranged to form a predetermined angle (e.g., 40° to 50°) counterclockwise with respect to the absorption axis of the polarizing member included in the display element 12, and the other may be arranged to form a predetermined angle (e.g., 40° to 50°) clockwise with respect to the absorption axis of the polarizing member. In this case, unlike the example shown in FIG. 2, the absorption axis of the polarizing member included in the display element 12 and the reflection axis of the reflective polarizing member 14a included in the reflecting portion 14 may be arranged approximately perpendicular to each other. The first phase difference member 20 and the second phase difference member 22 are arranged so that the angle between their respective slow axes is, for example, 83° to 97°, preferably 84° to 96°, more preferably 85° to 95°, even more preferably 86° to 94°, and even more preferably 87° to 93°. The slow axis of the first phase difference member 20 and the slow axis of the second phase difference member 22 satisfy such a relationship, so that the above-mentioned ellipticity can be satisfactorily achieved.

The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples. The test and evaluation methods in the examples are as follows. Note that "parts" means "parts by weight" unless otherwise specified, and "%" means "% by weight" unless otherwise specified.

(1) Thickness Thicknesses of 10 μm or less were measured using a scanning electron microscope (manufactured by JEOL Ltd., product name "JSM-7100F"), and thicknesses of more than 10 μm were measured using a digital micrometer (manufactured by Anritsu Corporation, product name "KC-351C").
(2) In-plane phase difference Re(λ)
The width direction center and both ends of the retardation film were cut into squares with a width of 50 mm and a length of 50 mm, with one side parallel to the width direction of the film, to prepare samples. The in-plane retardation of the samples at each wavelength at 23° C. was measured using a Mueller matrix polarimeter (manufactured by Axometrics, product name “Axoscan”).
(3) Single transmittance and polarization degree of polarizing film The single transmittance Ts, parallel transmittance Tp, and crossed transmittance Tc of the polarizing film were measured using a spectrophotometer (Otsuka Electronics Co., Ltd., "LPF-200"). These Ts, Tp, and Tc are Y values measured using a 2-degree visual field (C light source) according to JIS Z8701 and corrected for visibility. The polarization degree of the polarizing film was calculated from the obtained Tp and Tc using the following formula.
Degree of polarization (%) = {(Tp-Tc)/(Tp+Tc)} ^1/2 ×100
(4) Thickness Variation The retardation film was cut into a size of 100 mm × 100 mm to prepare a measurement sample. As shown in Figure 4, the thickness was measured at five points, including the center of the measurement sample and four points 10 mm apart from the center on the top, bottom, left, and right sides, and the difference between the maximum and minimum values was taken as the thickness variation.
(5) ISC Value The ISC value of the retardation film was measured using EyeScale-4W manufactured by I-System Co., Ltd. Specifically, based on the specifications of the measurement device, the in-plane unevenness was calculated as the ISC value in the ISC measurement mode of a 3CCD image sensor.
5 is a diagram for explaining a method for measuring the ISC value, and is a schematic diagram of the arrangement of a light source, a retardation film, a screen, and a CCD camera viewed from above. As shown in FIG. 5, the light source L, the retardation film M, and the screen S were arranged in this order, and the transmitted image projected onto the screen S was measured by the CCD camera C. The retardation film M was attached to an alkali-free glass plate (manufactured by Corning, 1737) and was used for measurement in a state in which the glass plate was arranged on the light source L side.
The light source L was positioned so that the distance in the X-axis direction from the retardation film M was 10 to 60 cm. The light source L was positioned so that the distance in the X-axis direction from the screen S was 70 to 130 cm. The CCD camera C was positioned so that the distance in the Y-axis direction from the retardation film M was 3 to 30 cm. The CCD camera C was positioned so that the distance in the X-axis direction from the screen S was 70 to 130 cm.

[Production Example 1-1: Preparation of Retardation Film]
A batch polymerization apparatus consisting of two vertical reactors equipped with stirring blades and a reflux condenser controlled at 100° C. was charged with 29.60 parts by weight (0.046 mol) of bis[9-(2-phenoxycarbonylethyl)fluoren-9-yl]methane, 29.21 parts by weight (0.200 mol) of isosorbide (ISB), 42.28 parts by weight (0.139 mol) of spiroglycol (SPG), 63.77 parts by weight (0.298 mol) of diphenyl carbonate (DPC), and 1.19×10 ⁻² parts by weight (6.78×10 ⁻⁵ mol) of calcium acetate monohydrate as a catalyst. After the inside of the reactor was replaced with nitrogen under reduced pressure, the inside 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. When the predetermined power was reached, nitrogen was introduced into the reactor 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 set temperature: 250°C), a T-die (width 200 mm, set temperature: 250°C), a chill roll (set 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 stretch ratio of 2.7 times.
Thus, a retardation film having a thickness of 47 μm, an Re(590) of 143 nm, and an Nz coefficient of 1.2 was obtained. The obtained retardation film had a Re(450)/Re(550) of 0.856. The ISC value and thickness variation of the retardation film are shown in Table 1.

[Production Example 2: Preparation of polarizing film]
As a thermoplastic resin substrate, a long amorphous isophthalic copolymerized polyethylene terephthalate film (thickness: 100 μm) having a Tg of about 75° C. was used, and 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 2.4 times in the machine direction (longitudinal direction) in an oven at 130° C. (auxiliary in-air stretching treatment).
Next, the laminate was immersed in an insolubilizing bath (a boric acid aqueous solution obtained by mixing 4 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 40° C. for 30 seconds (insolubilizing treatment).
Next, the film was immersed in a dye bath (an aqueous iodine solution obtained by mixing iodine and potassium iodide in a weight ratio of 1:7 with 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 absorptive polarizing film would have a desired value (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 about 90° C., the laminate was brought into contact with a SUS heated roll whose surface temperature was maintained at about 75° C. (drying shrinkage treatment). The shrinkage rate of the laminate in the width direction due to the drying shrinkage treatment was 5.2%.
In this manner, an absorptive polarizing film having a thickness of about 5 μm was formed on the resin substrate.
A cycloolefin resin film (thickness: 25 μm) was attached as a protective layer to the surface of the obtained absorptive polarizing film (the surface opposite to the resin substrate) via an ultraviolet-curable adhesive. Specifically, the curable adhesive was applied so that the total thickness 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. Then, the resin substrate was peeled off.
This resulted in a polarizing film having a cycloolefin resin film/absorption-type polarizing film structure. The polarizing film had a single transmittance (Ts) of 43.4% and a polarization degree of 99.993%.

[Example 1]
As the λ/4 member 1, the λ/4 member 2, the λ/4 member 3, and the λ/4 member 4, four sheets of the retardation film 1 obtained in Production Example 1-1 were prepared, and these were laminated, and further the polarizing film obtained in Production Example 2 was laminated to obtain a laminate 1 and a laminate 2. The laminate 1 is a laminate in which the polarizing film, the λ/4 member 1, the λ/4 member 2, the λ/4 member 3, and the λ/4 member 4 are laminated in this order, and the laminate 2 is a laminate in which the λ/4 member 1, the λ/4 member 2, the λ/4 member 3, the λ/4 member 4, and the polarizing film are laminated in this order.
Adjacent films were superposed via an acrylic adhesive layer (manufactured by Nitto Denko Corporation, thickness 5 μm). In the superposition, the relationship between the slow axis of each retardation film and the absorption axis of the polarizing film was such that, when the absorption axis direction of the polarizing film when the laminate was viewed from the λ/4 member 1 side rather than the λ/4 member 2 was taken as the reference (0°), the angle of the slow axis direction of the λ/4 member 1 was −45°, the angle of the slow axis direction of the λ/4 member 2 was −45°, the angle of the slow axis direction of the λ/4 member 3 was +45°, and the angle of the slow axis direction of the λ/4 member 4 was +45°. Here, “+” means clockwise and “−” means counterclockwise.

[Example 2]
A laminate was obtained in the same manner as in Example 1, except that the angle of the slow axis direction of the λ/4 member 2 was changed from −45° to −49°, the angle of the slow axis direction of the λ/4 member 3 was changed from +45° to +49°, and the angle of the slow axis direction of the λ/4 member 4 was changed from +45° to +49°.

[Comparative Example 1]
A laminate was obtained in the same manner as in Example 1, except that the angle of the slow axis direction of the λ/4 member 2 was changed from −45° to −53°, the angle of the slow axis direction of the λ/4 member 3 was changed from +45° to +53°, and the angle of the slow axis direction of the λ/4 member 4 was changed from +45° to +53°.

<Evaluation>
The following evaluations were carried out for each of the Examples and Comparative Examples. The evaluation results are summarized in Table 2.
1. Ellipticity The ellipticity of the laminate 1 of each of the examples and comparative examples was measured. Specifically, the ellipticity was measured at 23° C. by irradiating light having a wavelength of 550 nm onto the polarizing film side of the laminate 1 using a Mueller matrix polarimeter (manufactured by Axometrics, product name "Axoscan").
2. Polarization characteristics The single transmittance and the degree of polarization of the laminate 2 of each Example and Comparative Example were measured. Specifically, a spectrophotometer (Otsuka Electronics Co., Ltd., "LPF-200") was used to make linearly polarized light, the polarization direction of which is perpendicular to the absorption axis direction of the polarizing film, incident on the laminate 2 from the λ/4 member 1 side, and the single transmittance Ts, parallel transmittance Tp, and crossed transmittance Tc were measured. These 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 of the laminate was calculated using the formula described in (3) above.
Table 2 also shows the results of the absorption axis transmittance (main transmittance: k2).

The laminate 1 and laminate 2 produced in the examples and comparative examples are simple evaluation models of the display system according to the embodiment of the present invention. Specifically, the laminate 1 can reproduce the state of polarization when entering the reflector 14 in the display system according to the embodiment of the present invention. The laminate 2 in the evaluation of the polarization characteristics can, for example, evaluate the user's visibility in the display system according to the embodiment of the present invention. Specifically, in the display system according to the embodiment of the present invention, the light that enters the laminate 2 from the λ/4 member 1 side and exits from the polarizing film side can be evaluated as light that is emitted from the display element 12 and passes through the first λ/4 member 20 and the second λ/4 member 22 in this order, is reflected by the reflector 14 and the half mirror 18, and then passes through the second λ/4 member 22 two more times, and then passes through the reflector 14 and exits forward.

In each embodiment, a high degree of polarization (low cross transmittance) can be achieved, and such a display system can effectively suppress light leakage. Since the image can be enlarged in the lens portion of the display system (for example, by a convex lens), differences in polarization characteristics can have a significant effect on visibility.
In each of the examples, the absorption axis transmittance (k2) is low. A low absorption axis transmittance reduces the polarized component in the reflection axis direction in the reflecting section 14, and light loss can be suppressed.

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 display system according to the embodiment of the present invention can be used in a display device such as VR goggles, for example.

2 Display system 12 Display element 14 Reflection section 14a Reflective polarizing member 16 First lens section 18 Half mirror 20 First phase difference member 22 Second phase difference member 24 Second lens section

Claims (14)

1. A display system for displaying an image to a user, comprising:
a display element having a display surface that emits light representing an image forward via a polarizing member;
a reflecting section disposed in front of the display element, the reflecting section including a reflective polarizing member and configured to reflect light emitted from the display element;
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 first λ/4 member disposed on an optical path between the display element and the half mirror;
a second λ/4 member disposed on an optical path between the half mirror and the reflecting portion,
The ellipticity of the polarized light transmitted through the reflecting portion is 0.015 or less.
Display system. The display system according to claim 1, wherein a space is formed between the first λ/4 member and the second λ/4 member. The display system of claim 1, wherein the display element and the first λ/4 member are integral. The display system of claim 1, wherein the first lens portion and the second λ/4 member are integral. The display system of claim 1, wherein the absolute value of the difference between the in-plane retardation (a) of the first λ/4 member and the in-plane retardation (b) of the second λ/4 member is 3.5 nm or less. The display system according to claim 1, wherein the angle between the slow axis of the first λ/4 member and the slow axis of the second λ/4 member is 7° or less or 83° to 97°. The display system of claim 1, wherein the ISC values of the first λ/4 member and the second λ/4 member are each 50 or less. The display system of claim 1, wherein the thickness of the first λ/4 member and the second λ/4 member is 100 μm or less. The display system of claim 1, wherein the thickness variation of the first λ/4 member and the second λ/4 member is 1 μm or less, respectively. The display system of claim 1, wherein the ISC value per unit thickness of the first λ/4 member and the second λ/4 member is 1 or less. 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 display system 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°. A display comprising a display system according to any one of claims 1 to 11. A method for manufacturing a display comprising the display system according to any one of claims 1 to 11. A step of passing the light representing the image outputted through the polarizing member through a first λ/4 member;
A step of passing the light having passed through the first λ/4 member through a half mirror and a first lens portion;
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;
and allowing the light reflected by the reflecting portion and the half mirror to pass through the reflecting portion by the second λ/4 member,
The ellipticity of the polarized light transmitted through the reflecting portion is 0.015 or less.
Display method.

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