Lens unit, display body, and display method

Abstract

The invention provides a lens part capable of realizing light weight and improved visibility of VR goggles. A lens unit according to an embodiment of the present invention is used in a display system that displays an image to a user, and is provided with: a reflective polarizing member that reflects light that has been emitted forward from a display surface of a display element that displays an image and has passed through the polarizing member and a first [lambda] / 4 member; a first lens portion disposed on an optical path between the display element and the reflective polarization member; a half mirror that is disposed between the display element and the first lens unit, transmits the light emitted from the display element, and reflects the light reflected by the reflective polarization member toward the reflective polarization member; a second lens section disposed in front of the reflective polarization member; and a phase difference member disposed on an optical path between the half mirror and the reflective polarization member and including a second [lambda] / 4 member, the phase difference member including a first phase difference layer and an adhesive layer. The refractive index (n1) of the first phase difference layer at a wavelength of 550 nm and the refractive index (n0) of the adhesive layer at a wavelength of 550 nm satisfy the relationship of the following formula (1): | n1-n0 | < 0.05 (1).

Description

TECHNICAL FIELD

[0001] The present application relates to a lens portion, a display body, and a display method. BACKGROUND

[0002] Image display devices typified by liquid crystal display devices and electroluminescence (EL) display devices (for example, organic EL display devices) are rapidly spreading. In image display devices, in order to achieve image display and improve the performance of image display, optical members such as polarizing members and phase difference members are generally used (for example, refer to Patent Document 1).

[0003] In recent years, new uses of image display devices have been developed. For example, head-mounted displays with displays (VR head-mounted displays) for realizing Virtual Reality (VR) have begun to be commercialized. Since the use of VR head-mounted displays in various scenes has been studied, it is desired to reduce the weight, improve the visual recognition, and the like. The reduction in weight can be achieved, for example, by thinning the lenses for VR head-mounted displays. On the other hand, it is also desired to develop optical members suitable for display systems using thin lenses.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT DOCUMENTS

[0006] Patent Document 1: Japanese Patent Application Publication No. 2021-103286 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] In view of the above, a main object of the present application is to provide a lens portion capable of achieving a reduction in weight and an improvement in visual recognition of a VR head-mounted display.

[0009] MEANS FOR SOLVING THE PROBLEMS

[0010] 1. A lens portion according to an embodiment of the present application for a display system that displays an image to a user, the lens portion comprising:

[0011] a reflection-type polarizing member that reflects light that has exited from a display surface of a display element that displays an image toward the front and that has passed through a polarizing member and a first λ / 4 member;

[0012] a first lens portion disposed on an optical path between the display element and the reflection-type polarizing member;

[0013] a half mirror disposed between the display element and the first lens portion, that transmits light that has exited from the display element, and that reflects light that has been reflected at the reflection-type polarizing member toward the reflection-type polarizing member;

[0014] a second lens portion disposed in front of the above-described reflective polarizing member; and

[0015] a phase difference member including a second λ / 4 member disposed on an optical path between the above-described half mirror and the above-described reflective polarizing member,

[0016] wherein the above-described phase difference member includes a first phase difference layer and a bonding layer, the refractive index n1 of the above-described first phase difference layer at a wavelength of 550 nm and the refractive index n0 of the above-described bonding layer at a wavelength of 550 nm satisfy the following relation of Expression (1):

[0017] | n1 - n0 | < 0.05 ··· (1).

[0018] 2. In the lens portion described in the above 1, the refractive index n0 of the above-described bonding layer at a wavelength of 550 nm can satisfy the following Expression (2):

[0019] 1.40 < n0 < 1.55 ··· (2).

[0020] 3. In the lens portion described in the above 1 or 2, the refractive index n1 of the above-described first phase difference layer at a wavelength of 550 nm can satisfy the following Expression (3):

[0021] 1.40 < n1 < 1.60 ··· (3).

[0022] 4. In the lens portion described in any one of the above 1 to 3, the phase difference member can include the above-described first phase difference layer, the above-described bonding layer, and a second phase difference layer in this order, and the above-described n1 and n0 and the refractive index n2 of the above-described second phase difference layer at a wavelength of 550 nm satisfy the following relations of Expressions (4) and (5):

[0023] | n2 - n0 | ≥ | n1 - n0 | ··· (4)

[0024] | n1 - n0 | + | n2 - n0 | < 0.15 ··· (5).

[0025] 5. The lens portion described in any one of the above 1 to 4 can include a stacked portion including the above-described phase difference member.

[0026] 6. In the lens portion described in the above 5, the stacked portion can include the above-described reflective polarizing member.

[0027] 7. In the lens portion described in the above 6, the stacked portion can include an absorption-type polarizing member disposed between the above-described reflective polarizing member and the above-described second lens portion.

[0028] 8. In the lens portion described in the above 6 or 7, the stacked portion can include a third λ / 4 member disposed between the above-described reflective polarizing member and the above-described second lens portion.

[0029] 9. The lens portion according to any one of claims 5 to 8, wherein the stacked portion includes a protective member disposed in front of the phase difference member.

[0030] 10. A display according to an embodiment of the present application includes the lens portion according to any one of claims 1 to 9.

[0031] 11. A display method according to an embodiment of the present application includes:

[0032] a step of passing light of a display image that has exited via a polarizing member and a first λ / 4 member through a half mirror and a first lens portion;

[0033] a step of passing light that has passed through the half mirror and the first lens portion through a phase difference member including a second λ / 4 member;

[0034] a step of reflecting light that has passed through the phase difference member at a reflective polarizing member toward the half mirror;

[0035] a step of passing light that has been reflected at the reflective polarizing member and the half mirror through the phase difference member and allowing the light to be transmitted through the reflective polarizing member; and

[0036] a step of passing light that has been transmitted through the reflective polarizing member through a second lens portion,

[0037] wherein the phase difference member includes a first phase difference layer and a bonding layer, and a refractive index nl of the first phase difference layer at a wavelength of 550 nm and a refractive index n0 of the bonding layer at a wavelength of 550 nm satisfy the following relation of Expression (1):

[0038] | nl - n0 | < 0.05 ··· (1).

[0039] Effects of the Invention

[0040] According to the lens portion of the embodiment of the present application, it is possible to achieve light weight and improved visual recognition of a VR goggle. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 is a schematic diagram showing a brief configuration of a display system according to an embodiment of the present application.

[0042] Figure 2 is a schematic diagram showing a detailed configuration of a lens portion of the display system shown in Figure 1

[0043] Figure 3 is a schematic perspective view showing an example of a multilayer structure included in a reflective polarizing film.​

[0044] Figure 4 is a schematic cross-sectional view showing another example of a detailed configuration of a lens portion of the display system. Figure 1

[0045] Figure 5 is a view for explaining a method for measuring transmittance.

[0046] Explanation of symbols

[0047] 2 display system, 4 lens portion, 12 display element, 14 reflective polarizing member, 16 first lens portion, 18 half mirror, 20 first phase difference member, 22 second phase difference member, 22a second λ / 4 member, 22b another phase difference layer, 24 second lens portion, 28 absorptive polarizing member, 30 third phase difference member, 31 first protective member, 32 second protective member, 41 adhesive layer, 42 adhesive layer, 43 adhesive layer, 44 adhesive layer, 45 adhesive layer, 46 adhesive layer, 50 adhesive layer, 100 first stacked portion, 200 second stacked portion. DETAILED DESCRIPTION

[0048] Hereinafter, embodiments of the present application will be described with reference to the drawings, but the present application is not limited to these embodiments. In order to more clearly describe the embodiments, the drawings sometimes schematically represent the width, thickness, shape, and the like of each portion compared to the embodiments, but are only examples, and do not limit the explanation of the present application. In addition, with regard to the drawings, the same symbol is sometimes marked on the same or equivalent elements, and repeated explanation is omitted.

[0049] (Definition of terms and symbols)

[0050] The definition of terms and symbols in this specification is as follows.

[0051] (1) Refractive index (nx, ny, nz)

[0052] "nx" is the refractive index in the direction in which the in-plane refractive index is the largest (i.e., the slow axis direction), "ny" is the refractive index in the direction in the plane orthogonal to the slow axis (i.e., the fast axis direction), and "nz" is the refractive index in the thickness direction.

[0053] (2) In-plane retardation (Re)

[0054] "Re(λ)" is the in-plane retardation measured at 23°C with light of wavelength λ nm. For example, "Re(550)" is the in-plane retardation measured at 23°C with light of wavelength 550 nm. When the thickness of a layer (film) is set to d (nm), Re(λ) can be found by the formula: Re(λ) = (nx - ny) x d. ​

[0055] (3) Phase difference in thickness direction (Rth)

[0056] “Rth(λ)” is a phase difference in thickness direction measured at 23°C with light of wavelength λ nm. For example, “Rth(550)” is a phase difference in thickness direction measured at 23°C with light of wavelength 550 nm. When the thickness of a layer (film) is set as d (nm), Rth(λ) can be found by the formula: Rth(λ) = (nx - nz) x d.

[0057] (4) Nz coefficient

[0058] The Nz coefficient can be found by Nz = Rth / Re.

[0059] (5) Angle

[0060] In the present specification, when an angle is mentioned, the angle includes both clockwise and counterclockwise with respect to a reference direction. Thus, for example, “45°” means ±45°.

[0061] Figure 1 is a schematic view showing a brief configuration of a display system according to one embodiment of the present application. In Figure 1 , the arrangement and shape of each constituent element of the display system 2 are schematically shown. The display system 2 is provided with a display element 12, a reflective polarizing member 14, a first lens portion 16, a half mirror 18, a first phase difference member 20, a second phase difference member 22, and a second lens portion 24. The reflective polarizing member 14 is arranged on the display surface 12a side of the display element 12, that is, on the front side, and can reflect light after the light is emitted from the display element 12. The first lens portion 16 is arranged on the optical path between the display element 12 and the reflective polarizing member 14, and the half mirror 18 is arranged between the display element 12 and the first lens portion 16. The first phase difference member 20 is arranged on the optical path between the display element 12 and the half mirror 18, and the second phase difference member 22 is arranged on the optical path between the half mirror 18 and the reflective polarizing member 14.

[0062] The constituent elements arranged on the front side of the half mirror (the half mirror 18, the first lens portion 16, the second phase difference member 22, the reflective polarizing member 14, and the second lens portion 24 in the illustrated example) are sometimes collectively referred to as a lens portion (the lens portion 4).

[0063] 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 becomes first linearly polarized light, for example, by passing through a polarizing member (typically, a polarizing film) possibly included in the display element 12.

[0064] The first phase difference member 20 includes a first λ / 4 member capable of converting the first linearly polarized light incident to the first phase difference member 20 into first circularly polarized light. In a case where the first phase difference member does not include a member other than the first λ / 4 member, the first phase difference member can correspond to the first λ / 4 member. The first phase difference member 20 can be integrally provided to the display element 12.

[0065] The half mirror 18 transmits the light emitted from the display element 12 and reflects the light reflected at the reflective polarizing member 14 toward the reflective polarizing member 14. The half mirror 18 is integrally provided to the first lens portion 16.

[0066] The second phase difference member 22 includes a second λ / 4 member capable of transmitting the light reflected at the reflective polarizing member 14 and the half mirror 18 through the reflective polarizing member 14. In a case where the second phase difference member does not include a member other than the second λ / 4 member, the second phase difference member can correspond to the second λ / 4 member. The second phase difference member 22 can be integrally provided to the first lens portion 16.

[0067] The first circularly polarized light emitted from the first λ / 4 member included in the first phase difference member 20 passes through the half mirror 18 and the first lens portion 16 and is converted into second linearly polarized light by the second λ / 4 member included in the second phase difference member 22. The second linearly polarized light emitted from the second λ / 4 member is reflected toward the half mirror 18 without being transmitted through the reflective polarizing member 14. At this time, the polarization direction of the second linearly polarized light incident to the reflective polarizing member 14 is the same direction as the reflection axis of the reflective polarizing member 14. Therefore, the second linearly polarized light incident to the reflective polarizing member 14 is reflected at the reflective polarizing member 14.

[0068] The second linearly polarized light reflected at the reflective polarizing member 14 is converted into second circularly polarized light by the second λ / 4 member included in the second phase difference member 22, and the second circularly polarized light emitted from the second λ / 4 member is reflected at the half mirror 18 after passing through the first lens portion 16. The second circularly polarized light reflected at the half mirror 18 passes through the first lens portion 16 and is converted into third linearly polarized light by the second λ / 4 member included in the second phase difference member 22. The third linearly polarized light is transmitted through the reflective polarizing member 14. At this time, the polarization direction of the third linearly polarized light incident to the reflective polarizing member 14 is the same direction as the transmission axis of the reflective polarizing member 14. Therefore, the third linearly polarized light incident to the reflective polarizing member 14 is transmitted through the reflective polarizing member 14.

[0069] The light transmitted through the reflective polarizing member 14 is incident to the user's eye 26 after passing through the second lens portion 24.

[0070] For example, the absorption axis of the polarizing member included in the display element 12 and the reflection axis of the reflective polarizing member 14 can be arranged approximately in parallel to each other, or can be arranged approximately perpendicularly to each other. The angle formed by the absorption axis of the polarizing member included in the display element 12 and the slow axis of the first λ / 4 member included in the first phase difference member 20 is, for example, 40° to 50°, can be 42° to 48°, or can be approximately 45°. The angle formed by the absorption axis of the polarizing member included in the display element 12 and the slow axis of the second λ / 4 member included in the second phase difference member 22 is, for example, 40° to 50°, can be 42° to 48°, or can be approximately 45°.

[0071] The in-plane retardation Re(550) of the first λ / 4 member is, for example, 100 nm to 190 nm, can be 110 nm to 180 nm, or can be 130 nm to 160 nm, and can be 135 nm to 155 nm. The first λ / 4 member preferably exhibits a reverse dispersion wavelength characteristic in which the phase difference value increases in accordance with the wavelength of the measurement light. The Re(450) / Re(550) of the first λ / 4 member is, for example, 0.75 or more and less than 1, can be 0.8 or more and 0.95 or less.

[0072] The in-plane retardation Re(550) of the second λ / 4 member is, for example, 100 nm to 190 nm, can be 110 nm to 180 nm, or can be 130 nm to 160 nm, and can be 135 nm to 155 nm. The second λ / 4 member preferably exhibits a reverse dispersion wavelength characteristic in which the phase difference value increases in accordance with the wavelength of the measurement light. The Re(450) / Re(550) of the second λ / 4 member is, for example, 0.75 or more and less than 1, can be 0.8 or more and 0.95 or less.

[0073] In the lens portion 4, a space can be formed between the first lens portion 16 and the second lens portion 24. In this case, the member arranged between the first lens portion 16 and the second lens portion 24 is preferably provided integrally with either one of the first lens portion 16 and the second lens portion 24. For example, the member arranged between the first lens portion 16 and the second lens portion 24 is preferably integrated with either one of the first lens portion 16 and the second lens portion 24 via an adhesive layer. According to such a manner, for example, the handling properties of each member can be excellent. The adhesive layer can be formed of an adhesive, or can be formed of a bonding agent. Specifically, the adhesive layer can be an adhesive layer, or can be a bonding agent layer. The thickness of the adhesive layer is, for example, 0.05 μm to 30 μm.

[0074] Figure 2 is a schematic cross-sectional view showing an example of the detailed configuration of the lens portion of the display system shown in Figure 1 is a schematic cross-sectional view showing an example of the detailed configuration of the lens portion of the display system shown in Figure 2The first lens portion, the second lens portion, and a member disposed therebetween are shown. The lens portion 4 includes a first lens portion 16, a first stacked portion 100 disposed adjacent to the first lens portion 16, a second lens portion 24, and a second stacked portion 200 disposed adjacent to the second lens portion 24. In Figure 2 In the example shown, the first stacked portion 100 is disposed separately from the second stacked portion 200. Although not shown, a half mirror can be integrally provided to the first lens portion 16.

[0075] The first stacked portion 100 includes the second phase difference member 22 and an adhesive layer (e.g., an adhesive layer) 41 disposed between the first lens portion 16 and the second phase difference member 22, and is integrally provided to the first lens portion 16 via the adhesive layer 41. The first stacked portion 100 further includes a first protective member 31 disposed in front of the second phase difference member 22. The first protective member 31 is laminated to the second phase difference member 22 via an adhesive layer (e.g., an adhesive layer) 42, and is disposed adjacent to the second phase difference member 22. The first protective member 31 can be located at the most surface of the first stacked portion 100. Note that, in this specification, adjacent includes not only abutted together, but also abutted together via an adhesive layer.

[0076] In Figure 2 In the example shown, the second phase difference member 22 includes an additional phase difference layer 22b in addition to the second λ / 4 member 22a. The second phase difference member 22 has a laminated structure of the second λ / 4 member 22a and the additional phase difference layer 22b. As the additional phase difference layer 22b, a member whose refractive index characteristics can exhibit a relationship of nz> nx= ny (so-called positive C-plate) can be used, for example. In this case, as the second phase difference member 22, a member whose refractive index characteristics exhibit a relationship of nx> ny≥ nz can be used. Figure 2 As shown in the second phase difference member 22, it is preferable that the second λ / 4 member 22a be located at a position further forward than the positive C-plate 22b.

[0077] It is preferable that the refractive index characteristics of the above-described second λ / 4 member exhibit a relationship of nx> ny≥ nz. Here, "ny= nz" includes not only a case where ny and nz are completely equal, but also a case where they are substantially equal. Therefore, ny can be less than nz within a range that does not impair the effects of the present application. The Nz coefficient of the second λ / 4 member is preferably 0.9 to 3, more preferably 0.9 to 2.5, further preferably 0.9 to 1.5, and particularly preferably 0.9 to 1.3.

[0078] The second λ / 4 member is formed of any appropriate material that can satisfy the above-described characteristics. The second λ / 4 member can be, for example, a stretched film of a resin film or an alignment fixed layer of a liquid crystal compound.

[0079] As the resin contained in the resin film described above, 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 can be given. These resins can be used alone or in combination. As the method of combination, blending, copolymerization, and the like can be given. In the case where the second λ / 4 member exhibits a reverse dispersion wavelength characteristic, a resin film containing a polycarbonate-based resin or a polyester carbonate-based resin (hereinafter, sometimes referred to simply as a polycarbonate-based resin) can be suitably used.

[0080] As the polycarbonate-based resin described above, any appropriate polycarbonate-based resin can be used. 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 an alicyclic diol, an alicyclic dimethanol, a di-, tri-, or polyethylene glycol, and an alkylene glycol or a spiro glycol. It is preferable that the polycarbonate-based resin contain 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 an alicyclic dimethanol and / or a structural unit derived from a di-, tri-, or polyethylene glycol; it is further preferable to contain 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 can also contain a structural unit derived from another dihydroxy compound as necessary. Note that the details of the polycarbonate-based resin that can be suitably used for the second λ / 4 member and the method of forming the second λ / 4 member are described, for example, in Japanese Patent Application Publication No. 2014-10291, Japanese Patent Application Publication No. 2014-26266, Japanese Patent Application Publication No. 2015-212816, Japanese Patent Application Publication No. 2015-212817, and Japanese Patent Application Publication No. 2015-212818, the contents of which are incorporated herein by reference in their entirety.

[0081] The thickness of the second λ / 4 member composed of the stretched film of the resin film is, for example, 10 μm to 100 μm, preferably 10 μm to 70 μm, and more preferably 20 μm to 60 μm.

[0082] The alignment fixing layer of the liquid crystal compound is a layer in which the liquid crystal compound is aligned in a given direction within the layer and the alignment state thereof is fixed. Note that the "alignment fixing layer" is a concept that includes an alignment cured layer obtained by curing a liquid crystal monomer as described later. In the second λ / 4 member, typically, a rod-shaped liquid crystal compound is aligned in a state of being arranged in the slow axis direction of the second λ / 4 member (homogeneous alignment). As the rod-shaped liquid crystal compound, for example, a liquid crystal polymer and a liquid crystal monomer can be given. The liquid crystal compound preferably is polymerizable. If the liquid crystal compound is polymerizable, the alignment state of the liquid crystal compound can be fixed by performing polymerization after aligning the liquid crystal compound.

[0083] The alignment fixing layer of the liquid crystal compound (liquid crystal alignment fixing layer) can be formed by performing alignment treatment on the surface of a given substrate, applying a coating liquid containing a liquid crystal compound to the surface, and aligning the liquid crystal compound in a direction corresponding to the alignment treatment and fixing the alignment state. As the alignment treatment, any appropriate alignment treatment can be used. Specific examples of the alignment treatment include mechanical alignment treatment, physical alignment treatment, and chemical alignment treatment. Specific examples of the mechanical alignment treatment include rubbing treatment and stretching treatment. Specific examples of the physical alignment treatment include magnetic field alignment treatment and electric field alignment treatment. Specific examples of the chemical alignment treatment include oblique evaporation method and photo-alignment treatment. The treatment conditions of the various alignment treatments can be any appropriate conditions according to the purpose.

[0084] The alignment of the liquid crystal compound can be performed by performing treatment at a temperature at which the liquid crystal compound exhibits a liquid crystal phase, in accordance with the kind of the liquid crystal compound. By performing such temperature treatment, the liquid crystal compound is in a liquid crystal state, and the liquid crystal compound is aligned in accordance with the alignment treatment direction of the surface of the substrate.

[0085] In one embodiment, the fixing of the alignment state is performed by cooling the liquid crystal compound that has been aligned, as described above. In the case where the liquid crystal compound is polymerizable or cross-linkable, the fixing of the alignment state can be performed by performing polymerization treatment or cross-linking treatment on the liquid crystal compound that has been aligned, as described above.

[0086] As the liquid crystal compound, any appropriate liquid crystal polymer and / or liquid crystal monomer can be used. The liquid crystal polymer and the liquid crystal monomer can be used individually or in combination. Specific examples of the liquid crystal compound and the method of producing the liquid crystal alignment fixing layer are described in, for example, Japanese Patent Application Publication No. 2006-163343, Japanese Patent Application Publication No. 2006-178389, and International Publication No. WO 2018 / 123551. The descriptions of these publications are incorporated herein by reference.

[0087] The thickness of the second λ / 4 member composed of the liquid crystal alignment fixing layer is, for example, 1 μm to 10 μm, preferably 1 μm to 8 μm, more preferably 1 μm to 6 μm, further preferably 1 μm to 4 μm.

[0088] The phase difference Rth(550) in the thickness direction of the above-mentioned positive C-plate is preferably -50 nm to -300 nm, more preferably -70 nm to -250 nm, further preferably -90 nm to -200 nm, particularly preferably -100 nm to -180 nm. Here, "nx = ny" includes not only the case where nx and ny are strictly equal, but also the case where nx and ny are substantially equal. The in-plane phase difference Re(550) of the positive C-plate is, for example, less than 10 nm.

[0089] The positive C-plate is formed of any appropriate material capable of satisfying the above-mentioned characteristics. The positive C-plate can be, for example, a resin film or an alignment fixing layer of a liquid crystal compound.

[0090] As a material of the resin film constituting the positive C-plate, a resin material having a negative birefringence is typically exemplified. The resin having a negative birefringence is a resin that exhibits a property of showing a maximum refractive index in a direction at right angles to the direction of stretching in the case where unidirectional stretching has been performed. As the resin having a negative birefringence, for example, a resin in which a polar chemical bond, a functional group, or the like having a large anisotropy, such as an aromatic ring or a carbonyl group, is introduced into a side chain can be exemplified. As specific examples of the resin having a negative birefringence, an acrylic resin, a styrene resin, a maleimide resin, a modified polyolefin resin, a fumarate resin, and the like can be exemplified, and as specific examples thereof, the resins having a negative birefringence described in Japanese Patent Application Publication No. 2021-076759, Japanese Patent Application Laid-Open No. 2008-544304, Japanese Patent Application Laid-Open No. 2008-544317, and the like can be referred to. The above-mentioned resin material can be used alone or two or more kinds thereof can be used in combination.

[0091] The resin film constituting the positive C-plate can further contain any appropriate additive as needed. As specific examples of the additive, a plasticizer, a heat stabilizer, a light stabilizer, a lubricant, an antioxidant, an ultraviolet absorber, a flame retardant, a colorant, an antistatic agent, a compatibilizer, a crosslinking agent, a thickening agent, and the like can be exemplified. The kind and the content of the additive can be appropriately set according to the purpose. The content of the additive in the resin film is, for example, about 3% by mass to 10% by mass.

[0092] In one embodiment, the resin material described above can be used directly as a positive C-plate after being formed into a film. Specifically, the film after being formed can not be stretched, but can be used directly as a positive C-plate. For example, when a resin solution containing the resin material described above is applied to a support to be formed into a film (using a solution film formation method), stress can be generated on the support due to volume shrinkage when the resin solution is dried, and there can be a tendency for the molecular chains of the polymer to be oriented in the in-plane direction. When a resin material having a high birefringence and a negative intrinsic birefringence is used, a coating film having a large thickness-direction birefringence can be formed on the support by the shrinkage action when dried. Furthermore, the coating film formed can be used directly as a positive C-plate.

[0093] The thickness of the positive C-plate composed of the resin film is, for example, 1 μm to 40 μm, preferably 3 μm to 35 μm, and more preferably 5 μm to 30 μm.

[0094] As the alignment fixing layer of the liquid crystal compound constituting the positive C-plate, an alignment fixing layer of a liquid crystal material fixed to a homeotropic alignment can be preferably selected. The liquid crystal material (liquid crystal compound) capable of homeotropic alignment can be a liquid crystal monomer or a liquid crystal polymer. As a specific example of such a liquid crystal compound and a method of forming the positive C-plate, the liquid crystal compound and the method of forming the phase difference layer described in

[0020] to

[0028] of Japanese Patent Application Publication No. 2002-333642 can be mentioned.

[0095] The thickness of the positive C-plate composed of the alignment fixing layer of the liquid crystal compound is preferably 0.5 μm to 10 μm, more preferably 0.5 μm to 8 μm, and further preferably 0.5 μm to 5 μm.

[0096] The second phase difference member 22 includes at least a first phase difference layer and an adhesive layer disposed in direct contact with the first phase difference layer, and the first phase difference layer can be integrated with an adjacent member via the adhesive layer. In the illustrated example, the second phase difference member 22 includes a second λ / 4 member 22a, an adhesive layer 50, and a further phase difference layer 22b, and the second λ / 4 member 22a and the further phase difference layer 22b are disposed in direct contact with both sides of the adhesive layer 50, respectively. In this case, the first phase difference layer can be either the second λ / 4 member 22a or the further phase difference layer 22b.

[0097] The refractive index n1 of the first phase difference layer at a wavelength of 550 nm and the refractive index n0 of the adhesive layer 50 disposed in direct contact with the first phase difference layer at a wavelength of 550 nm preferably satisfy the following relation of formula (1). Specifically, the absolute value of the difference between the refractive index n1 and the refractive index n0 is preferably less than 0.05, and more preferably 0.04 or less, and can be 0.03 or less.

[0098] | n1 - n0 | < 0.05 · · · (1)

[0099] By satisfying such a relationship, a display system with extremely excellent visual recognition can be realized. Specifically, interface reflection caused by the refractive index difference between the layers at the lens portion can be suppressed, and a phenomenon in which an image called ghost appears to be a double image can be suppressed. In the display system, the first stacked portion can significantly affect the visual recognition of the display system because light passes through three times. By causing the second phase difference member included in the first stacked portion to satisfy such a relationship, the visual recognition of the display system can be greatly improved. Note that in the present embodiment, the refractive index at a wavelength of 550 nm, at which visibility is high (for example, light is easily recognized by the human eye), is focused on.

[0100] The adhesive layer 50 included in the second phase difference member 22 can be formed of an adhesive or an adhesive agent, for example. The refractive index n0 of the adhesive layer 50 at a wavelength of 550 nm is preferably more than 1.40 and less than 1.55. Specifically, the refractive index n0 of the adhesive layer 50 at a wavelength of 550 nm preferably satisfies the following formula (2).

[0101] 1.40 < n0 < 1.55 ··· (2)

[0102] The refractive index n1 of the first phase difference layer at a wavelength of 550 nm differs depending on the material of the first phase difference layer, for example, and is typically more than 1.40 and less than 1.70, and preferably more than 1.40 and less than 1.60. Specifically, the refractive index n1 of the first phase difference layer at a wavelength of 550 nm preferably satisfies the following formula (3), and more preferably satisfies the following formula (3)'. Such a refractive index n1 can be achieved by forming the phase difference layer of a resin film, for example.

[0103] 1.40 < n1 < 1.60 ··· (3)

[0104] 1.40 < n1 < 1.55 ··· (3)'

[0105] In the illustrated example, the second phase difference member 22 includes a second λ / 4 member 22a and another phase difference layer 22b that are disposed directly on both sides of the adhesive layer 50, respectively. As such, the second phase difference member 22 can include a first phase difference layer and a second phase difference layer that are disposed directly on both sides of the adhesive layer 50, respectively.

[0106] The refractive index of the first phase difference layer and the second phase difference layer at a wavelength of 550 nm can be the same or different. The refractive index n2 of the second phase difference layer at a wavelength of 550 nm is, for example, different depending on the material of which it is composed, and is typically more than 1.40 and less than 1.70. The refractive index n2 of the second phase difference layer at a wavelength of 550 nm can satisfy the following relation of Expression (4). Further, the refractive indices n1, n2, n0 preferably satisfy the following Expression (5), and more preferably satisfy the following Expression (5)'. By satisfying such a relation, visual recognition can be further improved.

[0107] | n2 - n0 | ≥ | n1 - n0 | · · · (4)

[0108] | n1 - n0 | + | n2 - n0 | < 0.15 · · · (5)

[0109] | n1 - n0 | + | n2 - n0 | < 0.13 · · · (5)'

[0110] As the adhesive agent that forms the adhesive layer 50, an adhesive agent that can satisfy the above Expressions (1) and / or (2) can be selected. In one embodiment, as the adhesive agent that forms the adhesive layer 50, a curable adhesive agent is used. In this case, the adhesive layer (adhesive agent layer) 50 can be a cured layer of a resin. As the curable adhesive agent, an ultraviolet curable adhesive agent can be preferably used. The above ultraviolet curable adhesive agent contains a curable monomer such as a compound having a (meth)acryl group, a compound having a vinyl group, or the like as a curable monomer. A compound having a (meth)acryl group can be preferably used. Here, the (meth)acryl group refers to an acryl group and / or a methacryl group. By appropriately selecting the curable monomer, for example, the above Expressions (1) and / or (2) can be satisfied.

[0111] The thickness of the adhesive layer 50 is preferably 10 μm or less, more preferably 5 μm or less, and further preferably 3 μm or less. According to such a thickness, for example, excellent smoothness can be obtained, which can contribute to improvement in visual recognition. On the other hand, the thickness of the adhesive layer 50 is preferably 0.5 μm or more.

[0112] As the adhesive forming the adhesive layer 50, an adhesive capable of satisfying the above-described formula (1) and / or (2) can be selected. As specific examples of the adhesive, an acrylic adhesive, a rubber-based adhesive, a silicone-based adhesive, a polyester-based adhesive, a urethane-based adhesive, an epoxy-based adhesive, and a polyether-based adhesive can be given. By adjusting the kind, amount, combination, and ratio of monomers of the base resin forming the adhesive, the amount of the crosslinking agent, the reaction temperature, the reaction time, and the like, an adhesive having desired properties corresponding to the purpose can be prepared. The base resin of the adhesive can be used alone or in combination with two or more. As the base resin, an acrylic resin can be preferably used.

[0113] The thickness of the adhesive layer (adhesive layer) formed by the adhesive can be set to any appropriate thickness. The thickness of the adhesive layer is preferably 20 μm or less, can be 15 μm or less, and can be 10 μm or less. According to such a thickness, for example, excellent smoothness can be achieved, which can contribute to the improvement of visual recognition.

[0114] Representatively, the above-described first protective member includes a substrate. The thickness of the substrate is preferably 5 μm to 80 μm, more preferably 10 μm to 50 μm, and further preferably 15 μm to 40 μm. The substrate can be composed of any appropriate film. As a material that becomes a main component of the film constituting the substrate, for example, a cellulose-based resin such as triacetyl cellulose (TAC), a polyester, a polyvinyl alcohol, a polycarbonate, a polyamide, a polyimide, a polyethersulfone, a polysulfone, a polystyrene, a cyclic olefin such as polynorbornene, a polyolefin, a (meth)acrylic, an acetate, and the like can be given. Here, (meth)acrylic refers to acrylic acid and / or methacrylic acid. In one embodiment, the substrate is preferably formed of a (meth)acrylic resin. By using a (meth)acrylic resin, film formation of a substrate having excellent smoothness can be achieved by extrusion molding. Furthermore, a protective member having excellent smoothness can be obtained.

[0115] The first protective member preferably has a substrate and a surface treatment layer formed on the substrate. The first protective member having the surface treatment layer can be arranged in such a manner that the surface treatment layer is positioned on the front side. Specifically, the surface treatment layer can be positioned on the most surface of the first layer stack. The surface treatment layer can have any appropriate function. For example, from the viewpoint of improving visual recognition, the surface treatment layer preferably has an antireflection function. The thickness of the surface treatment layer is preferably 0.5 μm to 10 μm, more preferably 1 μm to 7 μm, and further preferably 2 μm to 5 μm.

[0116] The second stacked section 200 includes a reflective polarizing element 14 and an adhesive layer (e.g., an adhesive layer) disposed between the reflective polarizing element 14 and the second lens unit 24. To improve visual recognition, the second stacked section 200 further includes an absorptive polarizing element 28 disposed between the reflective polarizing element 14 and the second lens unit 24. The absorptive polarizing element 28 is stacked in front of the reflective polarizing element 14 via an adhesive layer (e.g., an adhesive layer) 44. The reflection axis of the reflective polarizing element 14 and the absorption axis of the absorptive polarizing element 28 can be arranged approximately parallel to each other, and the transmission axis of the reflective polarizing element 14 and the transmission axis of the absorptive polarizing element 28 can be arranged approximately parallel to each other. By stacking them via the adhesive layer, the reflective polarizing element 14 and the absorptive polarizing element 28 are fixed to each other, thereby preventing the axial arrangement of the reflection axis and the absorption axis (transmission axis and transmission axis) from shifting. In addition, the adverse effects caused by the air layer that may form between the reflective polarizing element 14 and the absorptive polarizing element 28 can be suppressed.

[0117] The second laminated portion 200 further includes a second protective member 32 disposed behind the reflective polarizing member 14. The second protective member 32 is laminated on the reflective polarizing member 14 via an adhesive layer (e.g., an adhesive layer) 43. The second protective member 32 can be located on the outermost surface of the second laminated portion 200. The first protective member 31 and the second protective member 32 are disposed opposite to each other with a space therebetween. The second protective member, like the first protective member, can include a substrate. In addition, the second protective member preferably has a substrate and a surface treatment layer formed on the substrate. In this case, the surface treatment layer can be located on the outermost surface of the second laminated portion. Regarding the details of the substrate and the surface treatment layer, the same description as that of the first protective member can be applied.

[0118] like Figure 2 As shown, the second stacked portion 200 may further include a third phase difference member 30 disposed between the absorbing polarization member 28 and the second lens portion 24. The third phase difference member 30 is stacked on the absorbing polarization member 28 via an adhesive layer (e.g., an adhesive layer) 45. In addition, the third phase difference member 30 is stacked on the second lens portion 24 via an adhesive layer (e.g., an adhesive layer) 46, and the second stacked portion 200 is integrally provided on the second lens portion 24. The third phase difference member 30 includes, for example, a third λ / 4 member. The angle formed by the absorption axis of the absorbing polarization member 28 and the slow axis of the third λ / 4 member included in the third phase difference member 30 is, for example, 40° to 50°, may be 42° to 48°, or may be approximately 45°. By providing such a member, it is possible to prevent reflection of external light, for example, from the second lens portion 16 side. In the case where the third phase difference member does not include any member other than the third λ / 4 member, the third phase difference member may be equivalent to the third λ / 4 member.

[0119] The above-described reflective polarizing member can transmit polarized light (typically linearly polarized light) parallel to its transmission axis while reflecting light having a polarization state other than that. The reflective polarizing member is typically composed of a film having a multilayer structure (sometimes referred to as a reflective polarizing film). In this case, the thickness of the reflective polarizing member is, for example, 10 μm to 150 μm, preferably 20 μm to 100 μm, and further preferably 30 μm to 60 μm.

[0120] Figure 3 is a schematic perspective view showing an example of a multilayer structure included in a reflective polarizing film. The multilayer structure 14a alternately includes a layer A having birefringence and a layer B having substantially no birefringence. The total number of layers constituting the multilayer structure can be 50 to 1000. For example, the refractive index nx in the x-axis direction of the A layer is greater than the refractive index ny in the y-axis direction, the refractive index nx in the x-axis direction of the B layer is substantially the same as the refractive index ny in the y-axis direction, and the difference in refractive index between the A layer and the B layer is large in the x-axis direction and substantially zero in the y-axis direction. As a result, the x-axis direction can become a reflection axis and the y-axis direction can become a transmission axis. The difference in refractive index between the A layer and the B layer in the x-axis direction is preferably 0.2 to 0.3.

[0121] The above-described A layer is typically formed of a material that exhibits birefringence by stretching. As such a material, for example, naphthalene dicarboxylic acid polyester (e.g., polyethylene naphthalate), polycarbonate, and acrylic resin (e.g., polymethyl methacrylate) can be given. The above-described B layer is typically formed of a material that exhibits substantially no birefringence even if stretched. As such a material, for example, a copolymer polyester of naphthalene dicarboxylic acid and terephthalic acid can be given. The above-described multilayer structure can be formed by combining co-extrusion and stretching. For example, after extruding a material constituting the A layer and a material constituting the B layer, multilayerization is performed (e.g., using a multiplier). Subsequently, the obtained multilayer laminate is stretched. The x-axis direction of the illustrated example can correspond to the stretching direction.

[0122] As a commercially available product of the reflective polarizing film, for example, products with trade names "DBEF" and "APF" manufactured by 3M Company, and a product with the trade name "APCF" manufactured by Nitto Electric Industrial Co., Ltd. can be given.

[0123] The normal transmittance (Tc) of the reflective polarizing member (reflective polarizing film) can be, for example, 0.01% to 3%. The single transmittance (Ts) of the reflective polarizing member (reflective polarizing film) is, for example, 43% to 49%, and is preferably 45% to 47%. The degree of polarization (P) of the reflective polarizing member (reflective polarizing film) can be, for example, 92% to 99.99%.

[0124] The orthogonal transmittance, the monomer transmittance, and the polarization degree described above can be measured, for example, using an ultraviolet-visible spectrophotometer. The polarization degree P can be measured using an ultraviolet-visible spectrophotometer for the monomer transmittance Ts, the parallel transmittance Tp, and the orthogonal transmittance Tc, and calculated from the obtained Tp and Tc by the following formula. Note that Ts, Tp, and Tc are Y values obtained by measuring them in a 2-degree field of view (C light source) according to JIS Z8701 and performing visibility correction.

[0125] Polarization degree P (%) = {(Tp - Tc) / (Tp + Tc)} 1 / 2 x 100

[0126] The absorption-type polarizing member described above can typically include a resin film containing a dichroic substance (sometimes referred to as an absorption-type polarizing film). The thickness of the absorption-type polarizing film is, for example, 1 μm or more and 20 μm or less, can be 2 μm or more and 15 μm or less, can be 12 μm or less, can be 10 μm or less, can be 8 μm or less, can be 5 μm or less, or the like.

[0127] The absorption-type polarizing film described above can be made of a single layer of a resin film or can be made using a laminate of two or more layers.

[0128] In the case of being made of a single layer of a resin film, the absorption-type polarizing film can be obtained, for example, by subjecting a hydrophilic polymer film such as a polyvinyl alcohol (PVA)-based film, a partially formalized PVA-based film, an ethylene-vinyl acetate copolymer-based partially saponified film, or the like to a dyeing treatment using a dichroic substance such as iodine or a dichroic dye, a stretching treatment, or the like. Among them, an absorption-type polarizing film obtained by subjecting a PVA-based film to dyeing with iodine and uniaxially stretching it is preferred.

[0129] The dyeing with iodine described above can be performed, for example, by immersing a PVA-based film in an aqueous iodine solution. The stretching ratio of the uniaxial stretching described above is preferably 3 to 7 times. The stretching can be performed after the dyeing treatment or can be performed while dyeing. Alternatively, the dyeing can be performed after stretching. The PVA-based film can be subjected to swelling treatment, cross-linking treatment, cleaning treatment, drying treatment, or the like as needed.

[0130] As the laminate in the case of production using the above-described laminate of two or more layers, a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or a laminate of a resin substrate and a PVA-based resin layer formed by coating on the resin substrate can be given. An absorption-type polarizing film obtained using the laminate of a resin substrate and a PVA-based resin layer formed by coating on the resin substrate can be produced by, for example, coating a PVA-based resin solution on a resin substrate, drying the same to form a PVA-based resin layer on the resin substrate, and obtaining a laminate of a resin substrate and a PVA-based resin layer, and stretching and dyeing the laminate to produce an absorption-type polarizing film from the PVA-based resin layer. In the present embodiment, it is preferable to form a polyvinyl alcohol-based resin layer containing a halide and a polyvinyl alcohol-based resin on one side of the resin substrate. Stretching typically includes stretching the laminate by immersing it in an aqueous boric acid solution. In addition, stretching can further include, as necessary, stretching the laminate in a gas atmosphere at a high temperature (e.g., 95°C or higher) before stretching in the aqueous boric acid solution. In the present embodiment, it is preferable to subject the laminate to a drying shrinkage treatment by causing it to shrink by 2% or more in the width direction while being conveyed in the length direction by performing heating. Typically, the production method of the present embodiment includes sequentially applying an auxiliary stretching treatment in a gas atmosphere, a dyeing treatment, a stretching treatment in an aqueous solution, and a drying shrinkage treatment to the laminate. By introducing the auxiliary stretching, even in the case where PVA is coated on a thermoplastic resin, the crystallinity of the PVA can be improved, and high optical properties can be achieved. In addition, by simultaneously improving the orientation of the PVA in advance, problems such as a decrease in the orientation of the PVA, dissolution, and the like when immersed in water in the subsequent dyeing step and stretching step can be prevented, and high optical properties can be achieved. In addition, in the case where the PVA-based resin layer is immersed in a liquid, compared to the case where the PVA-based resin layer does not contain a halide, the orientation disorder of polyvinyl alcohol molecules and a decrease in the orientation can be suppressed. Thus, the optical properties of the absorption-type polarizing film obtained by a treatment process in which the laminate is immersed in a liquid such as a dyeing treatment and a stretching treatment in an aqueous solution can be improved. Further, by the drying shrinkage treatment, the laminate is shrunk in the width direction, and thus the optical properties can be improved. The obtained laminate of a resin substrate / absorption-type polarizing film can be used as it is (i.e., the resin substrate can be used as a protective layer for the absorption-type polarizing film), or the resin substrate can be peeled from the laminate of a resin substrate / absorption-type polarizing film, and a suitable protective layer corresponding to the purpose can be laminated on the peeled surface or on the surface on the opposite side of the peeled surface, and used. Details of such a production method of an absorption-type polarizing film are described in, for example, Japanese Patent Application Publication No. 2012-73580 and Japanese Patent No. 6470455. The entire contents of these publications are incorporated herein by reference.

[0131] The orthogonal transmittance (Tc) of the absorption-type polarizing member (absorption-type polarizing film) is preferably 0.5% or less, more preferably 0.1% or less, and further preferably 0.05% or less. The monomer transmittance (Ts) of the absorption-type polarizing member (absorption-type polarizing film) is, for example, 41.0% to 45.0%, and is preferably 42.0% or more. The degree of polarization (P) of the absorption-type polarizing member (absorption-type polarizing film) is, for example, 99.0% to 99.997%, and is preferably 99.9% or more.

[0132] The in-plane retardation Re(550) of the above-described third λ / 4 member is, for example, 100 nm to 190 nm, can be 110 nm to 180 nm, can be 130 nm to 160 nm, and can be 135 nm to 155 nm. The third λ / 4 member preferably exhibits a reverse dispersion wavelength characteristic in which the phase difference value increases in accordance with the wavelength of the measuring light. The Re(450) / Re(550) of the third λ / 4 member is, for example, 0.75 or more and less than 1, and can be 0.8 or more and 0.95 or less. The refractive index characteristic of the third λ / 4 member preferably exhibits a relationship of nx>ny≥nz. The Nz coefficient of the third λ / 4 member is preferably 0.9 to 3, more preferably 0.9 to 2.5, further preferably 0.9 to 1.5, and particularly preferably 0.9 to 1.3.

[0133] The third λ / 4 member is formed of any appropriate material capable of satisfying the above-described characteristics. The third λ / 4 member can be, for example, a stretched film of a resin film or an alignment fixed layer of a liquid crystal compound. The same description as that of the above-described second λ / 4 member can be applied to the third λ / 4 member composed of a stretched film of a resin film or an alignment fixed layer of a liquid crystal compound. The second λ / 4 member and the third λ / 4 member can be the same member in terms of the constitution (for example, the forming material, the thickness, the optical characteristic, and the like) or can be different members in terms of the constitution.

[0134] Figure 4 is a schematic cross-sectional view showing another example of the detailed configuration of the lens portion of the display system shown in Figure 1 is a schematic cross-sectional view showing another example of the detailed configuration of the lens portion of the display system shown in Figure 4 The lens portion 4 includes a first lens portion 16, a first stacked portion 100 disposed adjacent to the first lens portion 16, and a second lens portion 24. The first stacked portion 100 is disposed separately from the second lens portion 24.

[0135] The first stacked portion 100 includes a second phase difference member 22 having a stacked structure of the second λ / 4 member 22a and another phase difference layer 22b, a reflective-type polarizing member 14, an absorption-type polarizing member 28, a third phase difference member 30, and a first protective member 31. Further, adhesive layers (for example, adhesive layers) 41 to 45 that integrate the respective members are included.Figure 4 In the example shown, Figure 2 In the example shown, the member disposed between the first lens portion 16 and the second lens portion 24 is integrally provided to the first lens portion 16. Among them, only the first protective member 31 is provided as the protective member that interfaces with the space formed between the first lens portion 16 and the second lens portion 24.

[0136] Embodiment

[0137] Hereinafter, the present application will be specifically described in connection with embodiments, but the present application is not limited to these embodiments. Note that the thickness, the phase difference value, and the refractive index are values measured by the following measurement methods.

[0138] <Thickness>

[0139] The thickness of 10 μm or less was measured using a scanning electron microscope (manufactured by JEOL Ltd., product name "JSM-7100F"). The thickness of more than 10 μm was measured using a digital micrometer (manufactured by Anritsu Corporation, product name "KC-351C").

[0140] <Phase difference value>

[0141] The phase difference value at each wavelength at 23°C was measured using a Mueller matrix polarimeter (manufactured by Axometrics, product name "Axoscan").

[0142] <Refractive index>

[0143] The in-plane refractive index and the thickness-direction refractive index of the film or layer to be measured were measured using a prism coupler (model 2010 / M manufactured by Metricon), and the refractive index (average refractive index) was calculated by averaging them. The measurement temperature was set to 23°C, and the measurement wavelengths were set to 407 nm, 594 nm, and 782 nm. The refractive index at 550 nm was calculated from the obtained measurement values and the Cauchy dispersion formula.

[0144] [Embodiment 1]

[0145] (Production of λ / 4 member 1)

[0146] Polymerization was performed using a batch polymerization apparatus composed of two vertical reactors equipped with stirring blades and reflux condensers controlled to 100°C. Bis[9-(2-phenoxy carbonyl ethyl) fluorene-9-yl]methane 29.60 parts by mass (0.046 mol), isosorbide (ISB) 29.21 parts by mass (0.200 mol), spiro glycol (SPG) 42.28 parts by mass (0.139 mol), diphenyl carbonate (DPC) 63.77 parts by mass (0.298 mol), and calcium acetate monohydrate 1.19 x 10 -2 parts by mass (6.78 x 10 -5 After the inside of the reactor was replaced with nitrogen under reduced pressure, heating was performed using a heating medium, and stirring was started when the inside temperature reached 100°C. The inside temperature reached 220°C 40 minutes after the start of heating, and the pressure was reduced while the temperature was controlled to be maintained, and reached 13.3 kPa 90 minutes after reaching 220°C. Phenol vapor produced during the polymerization was introduced into a reflux condenser controlled to 100°C, and a certain amount of monomer components contained in the phenol vapor was returned to the reactor, and the uncondensed phenol vapor was introduced into a condenser controlled to 45°C and recovered. After the inside of the first reactor was temporarily returned to atmospheric pressure by introducing nitrogen, the reaction solution in which oligomerization had been performed in the first reactor was transferred to the second reactor. Subsequently, the inside of the second reactor was heated and reduced in pressure, and the inside temperature reached 240°C and the pressure reached 0.2 kPa 50 minutes later. Then, the polymerization was performed until a given stirring power was reached. At the time when the given power was reached, nitrogen was introduced into the reactor to return the pressure, and the produced polyester carbonate resin was extruded into water, and the strand was cut to obtain pellets.

[0147] After the obtained polyester carbonate resin (pellets) were vacuum dried at 80°C for 5 hours, a film forming apparatus 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 was used to produce a long resin film having a thickness of 135 μm. The obtained long resin film was stretched in the width direction at a stretching temperature of 143°C and a stretching ratio of 2.8 times to obtain a stretched film having a thickness of 47 μm. The Re(550) of the obtained stretched film was 143 nm, Re(450) / Re(550) was 0.86, and the Nz coefficient was 1.2. In addition, the refractive index of the obtained stretched film was 1.53.

[0148] (Formation of positive C plate 1)

[0149] In a pressure vessel equipped with a stirrer, a condenser, a nitrogen gas introduction tube, and a thermometer, 48 parts by weight of hydroxypropylmethylcellulose (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "METOLOSE 60SH-50"), 15,601 parts by weight of distilled water, 8,161 parts by weight of diisopropyl fumarate, 240 parts by weight of 3-ethyl-3-oxetanylmethyl acrylate, and 45 parts by weight of t-butyl peroxypivalate as a polymerization initiator were added, nitrogen bubbling was performed for 1 hour, and then radical suspension polymerization was performed by keeping the temperature at 49°C for 24 hours while stirring. Subsequently, the suspension containing the generated polymer particles was subjected to centrifugal separation after being cooled to room temperature. The obtained polymer was washed twice with distilled water and twice with methanol, and then subjected to reduced-pressure drying, thereby obtaining a fumaric acid ester-based resin.

[0150] The obtained fumaric acid ester-based resin was dissolved in a toluene / methyl ethyl ketone mixed solution (50% by weight toluene / 50% by weight methyl ethyl ketone) to prepare a solution having a solid content concentration of 20% by weight. Further, 5 parts by weight of tributyl trimellitate as a plasticizer was added to 100 parts by weight of the fumaric acid ester-based resin, and a coating material was prepared.

[0151] As the support film, a biaxially-stretched film of polyethylene terephthalate having a thickness of 75 μm and a width of 1,350 mm was prepared.

[0152] The roll of the support film was set to the unwinding section of the film forming apparatus, and the support film was unwound and transported to the downstream side while being coated with the above-mentioned coating material so as to have a dried film thickness of 6 μm, and then dried at 140°C. Thus, a positive C-plate 1 having an Rth(550) of -83 nm and a refractive index of 1.47 was formed on the support film.

[0153] (Preparation of the adhesive)

[0154] An adhesive was prepared by mixing 20 parts by weight of acryloyl morpholine (manufactured by Shinnihon Chemical Co., Ltd., "ACMO (registered trademark)"), 50 parts by weight of an unsaturated fatty acid hydroxyalkyl ester-modified ε-caprolactone (manufactured by DAICEL Corp., trade name "PLACCEL FA-1DDM"), 10 parts by weight of polyethylene glycol diacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name "LIGHT ACRYLATE 9EG-A"), 15 parts by weight of an acrylic polymer (manufactured by TOA GOHSEI CO., LTD., "ARFON UP-1190"), 3 parts by weight of a photopolymerization initiator (trade name "Omnirad 907" manufactured by IGM resins), and 2 parts by weight of a photopolymerization initiator (trade name "KAYACURE DETX-S" manufactured by Nippon Kayaku Co., Ltd.).

[0155] The obtained adhesive was irradiated with ultraviolet rays of a high-pressure mercury lamp to a cumulative light amount of 300 mJ / cm 2 The obtained adhesive layer of 1 μm in thickness had a refractive index of 1.51.

[0156] (Production of phase difference member)

[0157] The above positive C-plate 1 was attached to the above λ / 4 member 1 (stretched film) via the above adhesive (1 μm in thickness after photocuring), and a phase difference member was obtained.

[0158] [Example 2]

[0159] Instead of the λ / 4 member 1 (stretched film), the following λ / 4 member 2 was used, and otherwise, the same as in Example 1 was performed, and a phase difference member was obtained.

[0160] (Production of λ / 4 member 2)

[0161] A compound represented by formula (I) 55 parts by weight, a compound represented by formula (II) 25 parts by weight, and a compound represented by formula (III) 20 parts by weight were added to cyclopentanone (CPN) 400 parts by weight, and then heated to 60°C and stirred to dissolve. Then, the solution of the above compounds was returned to room temperature, and IRGACURE 907 (manufactured by BASF Japan Ltd.) 3 parts by weight, MEGAFAC F-554 (manufactured by DIC Corp.) 0.2 parts by weight, and p-methoxyphenol (MEHQ) 0.1 parts by weight were added to the solution of the above compounds, and further stirred. The solution after stirring was transparent and uniform. The obtained solution was filtered with a 0.20 μm membrane filter, and a polymerizable composition was obtained.

[0162] An alignment film was obtained by coating an oriented film with a polyimide solution on a glass substrate of 0.7 mm in thickness, drying at 100°C for 10 minutes, and baking at 200°C for 60 minutes.

[0163] Next, the obtained polymerizable composition was coated on the substrate (essentially the alignment film) by a spin coating method, and dried at 100°C for 2 minutes. After the obtained coated film was cooled to room temperature, ultraviolet rays were irradiated for 30 seconds at an intensity of 30 mW / cm 2 The obtained liquid crystal alignment fixing layer had a Re(550) of 130 nm, and a Re(450) / Re(550) of 0.851, and showed a reverse dispersion wavelength characteristic. In addition, the obtained liquid crystal alignment fixing layer had a refractive index of 1.57.

[0164] [Chemical Formula 1]

[0165]

[0166] [Chemical Formula 2]

[0167]

[0168] [Example 3]

[0169] Instead of the positive C-plate 1, the following positive C-plate 2 was used, and otherwise, the same as Example 1 was performed, and a phase difference member was obtained.

[0170] (Formation of the positive C-plate 2)

[0171] A liquid crystal coating solution was prepared by dissolving 20 parts by weight of a side chain type liquid crystal polymer 20 represented by the following Chemical Formula (1) (the numbers 65 and 35 in the formula represent mole% of monomer units, and are expressed as a block polymer for convenience: weight average molecular weight 5000), 80 parts by weight of a polymerizable liquid crystal (BASF Corporation: trade name Paliocolor LC242) which exhibits a nematic liquid crystal phase, and 5 parts by weight of a photopolymerization initiator (Chiba Specialty Chemicals Corporation: trade name IRGACURE 907) in 200 parts by weight of cyclopentanone. Then, the coating solution was applied to a PET substrate on which a vertical alignment treatment had been performed, using a wire bar coater, and then, the liquid crystal was oriented by heating and drying at 80°C for 4 minutes. The liquid crystal layer was irradiated with ultraviolet rays, and the liquid crystal layer was cured, whereby a positive C-plate 2 having a thickness of 4 μm, an Rth(550) of -100 nm, and a refractive index of 1.62 was formed on the substrate.

[0172] [Chemical Formula 3]

[0173]

[0174] [Comparative Example 1]

[0175] Instead of the λ / 4 member 1 (stretched film), the above-described λ / 4 member 2 was used, and instead of the positive C-plate 1, the above-described positive C-plate 2 was used, and otherwise, the same as Example 1 was performed, and a phase difference member was obtained.

[0176] [Comparative Example 2]

[0177] Instead of the λ / 4 member and the positive C-plate, the adhesives were used to laminate via the following adhesive layer, and otherwise, the same as Comparative Example 1 was performed, and a phase difference member was obtained.

[0178] (Formation of the adhesive layer)

[0179] In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introducing tube, and a condenser, a monomer mixture containing 92 parts by weight of butyl acrylate, 2.9 parts by weight of acrylic acid, 0.1 part by weight of 2-hydroxyethyl acrylate, and 5 parts by weight of N-acryloylmorpholine was added. Further, 0.1 part by weight of 2,2'-azobisisobutyronitrile as a polymerization initiator was added together with 200 parts by weight of ethyl acetate with respect to 100 parts by weight of the monomer mixture, and nitrogen gas was introduced while slowly stirring to replace the inside of the flask with nitrogen gas, and then the liquid temperature in the flask was maintained at about 55°C to perform a polymerization reaction for 8 hours, thereby preparing a solution of an acrylic polymer having a weight average molecular weight (Mw) of 1.78 million.

[0180] The obtained solution of the acrylic polymer was applied to a base film and dried to form an adhesive layer having a thickness of 5 μm and a refractive index of 1.47 on the base film.

[0181] <Assessment: Transmission Measurement>

[0182] The transmission was measured for the phase difference members obtained in the examples and comparative examples. As a measuring device, an ultraviolet-visible spectrophotometer (manufactured by Japan Spectroscopic Co., Ltd., V-7100) was used, the transmission spectrum was measured, and the transmission at a wavelength of 550 nm was read.

[0183] Three pieces of the phase difference member were prepared in each of the examples and comparative examples. These phase difference members were laminated using the following adhesive layer A for lamination to form a laminate. As shown in FIG. 1, the obtained laminate was adhered to an acrylic film F having a lactone ring structure having a thickness of 40 μm on both sides using the following adhesive layer A for lamination, and a measurement sample S was obtained. As shown in FIG. 2, when the three pieces of the phase difference member 22 were laminated, the phase difference member 22 located closest to the light source L of the measuring device was arranged so that the λ / 4 member 22a was located on the side of the detector D of the measuring device. The phase difference member 22 located in the middle was arranged so that the λ / 4 member 22a was located on the side of the light source L of the measuring device. The phase difference member 22 located closest to the detector D of the measuring device was arranged so that the λ / 4 member 22a was located on the side of the detector D of the measuring device. Note that the adhesive layers (adhesive layers or adhesive layers) 50 included in the phase difference members 22 were omitted in FIG. 1 for easy observation of the figure. Figure 5 Figure 5 Figure 5

[0184] ​​​The results of the measurement are shown in Table 1. "Difference" in Table 1 indicates the smaller one of the absolute value of the difference between the refractive index of the λ / 4 member and n0, and the absolute value of the difference between the refractive index of the positive C-plate and n0, and "total of differences" indicates the sum of the absolute value of the difference between the refractive index of the λ / 4 member and n0, and the absolute value of the difference between the refractive index of the positive C-plate and n0. In addition, the transmittance (92.0%) of the reference example in Table 1 indicates the transmittance of a measurement sample obtained by preparing one piece of the phase difference member of Example 3, and attaching an acrylic film F having a lactone ring structure having a thickness of 40 μm to both sides of the phase difference member using the adhesive layer A for lamination described below.

[0185] (Formation of the adhesive layer A for lamination)

[0186] A four-necked flask equipped with a stirring blade, a thermometer, a nitrogen introduction tube, and a condenser was charged with a monomer mixture containing 94.9 parts by weight of butyl acrylate, 5 parts by weight of acrylic acid, and 0.1 parts by weight of 2-hydroxyethyl acrylate. Further, 0.3 parts by weight of dibenzoyl peroxide as a polymerization initiator was added together with ethyl acetate with respect to 100 parts by weight of the monomer mixture, and the flask was subjected to nitrogen replacement while slowly stirring and introducing nitrogen. Then, the liquid temperature in the flask was maintained at 60°C, and a polymerization reaction was performed for 7 hours. Next, ethyl acetate was added to the obtained reaction solution, and the solid content concentration was adjusted to 30% by weight, thereby preparing a solution of an acrylic polymer having a weight average molecular weight (Mw) of 2.2 million.

[0187] With respect to 100 parts by weight of the solid content of the obtained acrylic polymer solution, 0.6 parts by weight of trimethylolpropane / toluene diisocyanate adduct (trade name: Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.), and 0.075 parts by weight of a silane coupling agent (trade name: KBM403, manufactured by Shin-Etsu Chemical Co., Ltd.) were compounded, thereby preparing an acrylic adhesive.

[0188] The obtained acrylic adhesive was applied to a base film and dried, thereby forming an adhesive layer A for lamination having a thickness of 15 μm on the base film.

[0189]

[0190] The transmittance of the examples was higher than that of the comparative example. Since the image can be enlarged by the lens portion (for example, using a convex lens), the transmittance of the phase difference member can have a significant influence on visual recognition.

[0191] The present application is not limited to the above-described embodiments, and various modifications can be made. For example, a configuration which is substantially the same as the configuration shown in the above-described embodiments, a configuration which exerts the same effects, or a configuration which achieves the same object can be substituted.

[0192] Industrial applicability

[0193] The lens portion of the embodiment of the present application can be used, for example, for a display body of VR goggles or the like.

Claims

1. A lens portion for a display system for displaying an image to a user, the lens portion comprising: a reflective polarizing member that reflects light that has exited from a display surface of a display element that displays an image, and that has passed through a polarizing member and a first λ / 4 member; a first lens portion disposed on an optical path between the display element and the reflective polarizing member; a half mirror disposed between the display element and the first lens portion, that transmits light that has exited from the display element, and that reflects light that has passed through the reflective polarizing member; a second lens portion disposed in front of the reflective polarizing member; and a phase difference member comprising a second λ / 4 member, disposed on an optical path between the half mirror and the reflective polarizing member, wherein the phase difference member comprises a first phase difference layer and a bonding layer, and a refractive index nl of the first phase difference layer at a wavelength of 550 nm and a refractive index n0 of the bonding layer at a wavelength of 550 nm satisfy the following relation of Expression (1): | nl - n0 | < 0.05 · · · (1).

2. The lens portion according to claim 1, wherein the refractive index n0 of the bonding layer at a wavelength of 550 nm satisfies the following Expression (2): 1.40 < n0 < 1.55 · · · (2).

3. The lens portion according to claim 1, wherein the refractive index nl of the first phase difference layer at a wavelength of 550 nm satisfies the following Expression (3): 1.40 < nl < 1.60 · · · (3).

4. The lens portion according to claim 1, wherein the phase difference member comprises the first phase difference layer, the bonding layer, and a second phase difference layer in this order, the nl and n0 and a refractive index n2 of the second phase difference layer at a wavelength of 550 nm satisfy the following Expressions (4) and (5): | n2 - n0 | > | nl - n0 | · · · (4); | nl - n0 | + | n2 - n0 | < 0.15 · · · (5).

5. The lens portion according to claim 1, comprising: a laminated portion comprising the phase difference member.

6. The lens portion according to claim 5, wherein the laminated portion comprises the reflective polarizing member.

7. The lens portion according to claim 6, wherein the laminated portion comprises an absorption-type polarizing member disposed between the reflective polarizing member and the second lens portion.

8. The lens portion according to claim 6, wherein the laminated portion comprises a third λ / 4 member disposed between the reflective polarizing member and the second lens portion.

9. The lens portion according to claim 5, wherein the laminated portion comprises a protective member disposed in front of the phase difference member.

10. A display body having the lens portion according to any one of claims 1 to 9.

11. A display method, the method comprising: a step of causing light of a display image that has exited via a polarizing member and a first λ / 4 member to pass through a half mirror and a first lens portion; ​ a step of passing light, which has passed through the half mirror and the first lens portion, through a phase difference member including a second λ / 4 member; a step of reflecting light, which has passed through the phase difference member, toward the half mirror by a reflective polarizing member; a step of allowing light, which has been reflected by the reflective polarizing member and the half mirror, to pass through the phase difference member and be transmitted through the reflective polarizing member; and a step of passing light, which has been transmitted through the reflective polarizing member, through a second lens portion, wherein the phase difference member includes a first phase difference layer and a bonding layer, and a refractive index n1 of the first phase difference layer at a wavelength of 550 nm and a refractive index n0 of the bonding layer at a wavelength of 550 nm satisfy the following formula (1): | n1 - n0 | < 0.05 ··· (1).

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