JP2024095144A - Lens portion, display body and display method - Google Patents

Abstract

To provide a lens part capable of achieving weight-saving and improved visibility of a VR goggle.SOLUTION: A lens part is to be used in a display system configured to display an image to a user. The lens part includes: a reflection type polarization member configured to reflect light emitted frontward from a display face of a display element showing the image and transmitted through a polarization member and a first λ/4 member; a first lens part arranged on an optical path between the display element and the reflection type polarization member; a half mirror arranged between the display element and the first lens part and configured to transmit the emitted light from the display element and reflect the light reflected at the reflection type polarization member toward the reflection type polarization member; a second lens part arranged in front of the reflection type polarization member; and a second λ/4 member arranged on an optical path between the half mirror and the reflection type polarization member. With regard to a first laminate part including the second λ/4 member and at least one layer of adhesive layer and a second laminate part including the reflection type polarization member and at least one layer of adhesive layer, an ISC value is 100 or less.SELECTED DRAWING: Figure 1

Description

The present invention relates to a lens unit, a display body, and a display method.

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

In recent years, new applications for image display devices have been developed. For example, goggles with displays (VR goggles) for realizing Virtual Reality (VR) have begun to be commercialized. Since VR goggles are being considered for use in a variety of situations, there is a demand for them to be lightweight and have improved visibility. Weight reduction can be achieved, for example, by making the lenses used in VR goggles thinner. On the other hand, there is also a demand for the development of optical components suitable for display systems using thin lenses.

JP 2021-103286 A

In view of the above, the primary objective of the present invention is to provide a lens section that can reduce the weight of VR goggles and improve visibility.

1. The lens unit according to an embodiment of the present invention is a lens unit used in a display system that displays an image to a user, comprising: a reflective polarizing element that reflects light that is emitted forward from a display surface of a display element that displays an image and passes through a polarizing element and a first λ/4 element; a first lens unit disposed on an optical path between the display element and the reflective polarizing element; a half mirror disposed between the display element and the first lens unit, which transmits the light emitted from the display element and reflects the light reflected by the reflective polarizing element toward the reflective polarizing element; a second lens unit disposed in front of the reflective polarizing element; and a second λ/4 element disposed on an optical path between the half mirror and the reflective polarizing element, and the ISC value between a first laminated unit including the second λ/4 element and at least one adhesive layer and a second laminated unit including the reflective polarizing element and at least one adhesive layer is 100 or less.
2. In the lens portion described in 1 above, the second stacked portion may include an absorptive polarizing member disposed between the reflective polarizing member and the second lens portion.
3. In the lens portion described in 1 or 2 above, the second stacked portion may include a third λ/4 member disposed between the reflective polarizing member and the second lens portion.
4. In the lens portion according to any one of 1 to 3 above, the first laminated portion and the second laminated portion may be disposed apart from each other.
5. In the lens portion described in any one of 1 to 4 above, the second stacked portion may include a second protective member disposed behind the reflective polarizing member.
6. In the lens portion described in any one of 1 to 5 above, the first stacked portion may include a first protective member disposed in front of the second λ/4 member.
7. In the lens portion according to any one of the above items 1 to 6, the total number of pressure-sensitive adhesive layers included in the first laminated portion and the second laminated portion may be three or more.
8. In the lens portion according to any one of the above 1 to 7, the pressure-sensitive adhesive layer included in the first laminated portion and the pressure-sensitive adhesive layer included in the second laminated portion may each have a thickness of 20 μm or less.
9. In the lens portion according to any one of the above items 1 to 8, the pressure-sensitive adhesive layer included in the first laminated portion and the pressure-sensitive adhesive layer included in the second laminated portion may each have a surface roughness Ra of 20 nm or less.
10. In the lens portion according to any one of the above items 1 to 9, the pressure-sensitive adhesive layer included in the first laminated portion and the pressure-sensitive adhesive layer included in the second laminated portion may each be a single layer body.
11. In the lens portion according to any one of 1 to 10 above, the first lens portion and the half mirror may be integral with each other.
12. A display according to an embodiment of the present invention has a lens portion according to any one of 1 to 11 above.

13. A display method according to an embodiment of the present invention includes the steps of: passing light representing an image emitted through a polarizing element and a first λ/4 element through a half mirror and a first lens unit; passing the light that has passed through the half mirror and the first lens unit through a second λ/4 element; reflecting the light that has passed through the second λ/4 element toward the half mirror with a reflective polarizing element; making the light reflected by the reflective polarizing element and the half mirror transmittable through the reflective polarizing element by the second λ/4 element; and passing the light that has transmitted through the reflective polarizing element through a second lens unit, and the ISC value of a first laminated unit including the second λ/4 element and at least one adhesive layer and a second laminated unit including the reflective polarizing element and at least one adhesive layer is 100 or less.

The lens portion according to the embodiment of the present invention can reduce the weight of VR goggles and improve visibility.

1 is a schematic diagram showing a general configuration of a display system according to an embodiment of the present invention. 2 is a schematic cross-sectional view showing an example of details of a lens portion of the display system shown in FIG. 1 . FIG. 2 is a schematic perspective view showing an example of a multilayer structure included in a reflective polarizing film. 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. Furthermore, in order to make the description clearer, the drawings may show the width, thickness, shape, etc. of each part more diagrammatically than the embodiments, but these are merely examples and do not limit the interpretation of the present invention.

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

Figure 1 is a schematic diagram showing the general configuration of a display system according to one embodiment of the present invention. In Figure 1, the arrangement and shape of each component of the display system 2 are illustrated. The display system 2 includes a display element 12, a reflective polarizing member 14, a first lens unit 16, a half mirror 18, a first phase difference member 20, a second phase difference member 22, and a second lens unit 24. The reflective polarizing member 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 unit 16 is disposed on the optical path between the display element 12 and the reflective polarizing member 14, and the half mirror 18 is disposed between the display element 12 and the first lens unit 16. The first phase difference member 20 is disposed on the optical path between the display element 12 and the half mirror 18, and the second phase difference member 22 is disposed on the optical path between the half mirror 18 and the reflective polarizing member 14.

The components arranged in front of the half mirror (in the illustrated example, the half mirror 18, the first lens section 16, the second phase difference member 22, the reflective polarizing member 14, and the second lens section 24) may be collectively referred to as the lens section (lens section 4).

The display element 12 is, for example, a liquid crystal display or an organic EL display, and has a display surface 12a for displaying an image. The light emitted from the display surface 12a passes through, for example, a polarizing member (typically, a polarizing film) that may be included in the display element 12, and is converted into a first linearly polarized light.

The first phase difference member 20 includes a first λ/4 member that can convert the first linearly polarized light incident on the first phase difference member 20 into a first circularly polarized light. When the first phase difference member does not include any member other than the first λ/4 member, the first phase difference member may correspond to the first λ/4 member. The first phase difference member 20 may be provided integrally with the display element 12.

The half mirror 18 transmits the light emitted from the display element 12 and reflects the light reflected by the reflective polarizing element 14 toward the reflective polarizing element 14. The half mirror 18 is integrally formed with the first lens portion 16.

The second phase difference member 22 includes a second λ/4 member that can transmit light reflected by the reflective polarizing member 14 and the half mirror 18 through the reflective polarizing member 14. If the second phase difference member does not include any member other than the second λ/4 member, the second phase difference member may correspond to the second λ/4 member. The second phase difference member 22 may be provided integrally with the first lens portion 16.

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 the 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 passing through the reflective polarizing member 14. At this time, the polarization direction of the second linearly polarized light incident on the reflective polarizing member 14 is the same as the reflection axis of the reflective polarizing member 14. Therefore, the second linearly polarized light incident on the reflective polarizing member 14 is reflected by the reflective polarizing member 14.

The second linearly polarized light reflected by the reflective polarizing element 14 is converted into the second circularly polarized light by the second λ/4 element included in the second phase difference element 22, and the second circularly polarized light emitted from the second λ/4 element passes through the first lens unit 16 and is reflected by the half mirror 18. The second circularly polarized light reflected by the half mirror 18 passes through the first lens unit 16 and is converted into the third linearly polarized light by the second λ/4 element included in the second phase difference element 22. The third linearly polarized light passes through the reflective polarizing element 14. At this time, the polarization direction of the third linearly polarized light incident on the reflective polarizing element 14 is the same as the transmission axis of the reflective polarizing element 14. Therefore, the third linearly polarized light incident on the reflective polarizing element 14 passes through the reflective polarizing element 14.

The light transmitted through the reflective polarizing element 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 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 λ/4 member included in 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 λ/4 member included in 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 retardation Re(550) of the first λ/4 member is, for example, 100 nm to 190 nm, and may be 110 nm to 180 nm, 130 nm to 160 nm, or 135 nm to 155 nm. The first λ/4 member preferably exhibits an inverse dispersion wavelength characteristic in which the retardation value increases according to the wavelength of the measurement light. The Re(450)/Re(550) of the first λ/4 member may be, for example, 0.75 or more and less than 1, or 0.8 or more and 0.95 or less.

The in-plane retardation Re(550) of the second λ/4 member is, for example, 100 nm to 190 nm, and may be 110 nm to 180 nm, 130 nm to 160 nm, or 135 nm to 155 nm. The second λ/4 member preferably exhibits an inverse dispersion wavelength characteristic in which the retardation value increases according to the wavelength of the measurement light. The Re(450)/Re(550) of the second λ/4 member may be, for example, 0.75 or more and less than 1, or 0.8 or more and 0.95 or less.

In the lens portion 4, a space may be formed between the first lens portion 16 and the second lens portion 24. In this case, it is preferable that the member disposed between the first lens portion 16 and the second lens portion 24 is integrally provided with either the first lens portion 16 or the second lens portion 24. For example, it is preferable that the member disposed between the first lens portion 16 and the second lens portion 24 is integrated with either the first lens portion 16 or the second lens portion 24 via an adhesive layer. According to such a configuration, for example, each member may be excellent in ease of handling. The adhesive layer may be formed of an adhesive or a pressure-sensitive adhesive. Specifically, the adhesive layer may be an adhesive layer or a pressure-sensitive adhesive layer. The thickness of the adhesive layer is, for example, 0.05 μm to 30 μm.

Figure 2 is a schematic cross-sectional view showing an example of the details of the lens unit of the display system shown in Figure 1. Specifically, Figure 2 shows a first lens unit, a second lens unit, and members disposed between them. The lens unit 4 includes a first lens unit 16, a first laminate unit 100 disposed adjacent to the first lens unit 16, a second lens unit 24, and a second laminate unit 200 disposed adjacent to the second lens unit 24. In the example shown in Figure 2, the first laminate unit 100 and the second laminate unit 200 are disposed at a distance from each other. Although not shown, a half mirror may be provided integrally with the first lens unit 16.

In the lens section 4, the ISC value between the first laminate section 100 and the second laminate section 200 is 100 or less, preferably 90 or less, more preferably 80 or less, and even more preferably 70 or less. By satisfying such an ISC value, a display system with extremely excellent visibility can be realized. Specifically, by satisfying such an ISC value, the generation of diffused light in the lens section can be suppressed, and the image can be prevented from becoming unclear. The ISC value can be an index of smoothness or unevenness. In practice, the lower limit of the ISC value between the first laminate section 100 and the second laminate section 200 is about 5.

The first laminated portion 100 includes a second phase difference member 22 and 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 by the adhesive layer 41. The first laminated 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 the adhesive layer 42. The first protective member 31 may be located on the outermost surface of the first laminated portion 100.

2, the second phase difference member 22 includes, in addition to the second λ/4 member 22a, a member (so-called positive C plate) 22b whose refractive index characteristics can exhibit the relationship nz>nx=ny. The second phase difference member 22 has a laminated structure of the second λ/4 member 22a and the positive C plate 22b. As shown in FIG. 2, in the second phase difference member 22, it is preferable that the second λ/4 member 22a is located forward of the positive C plate 22b. The second λ/4 member 22a and the positive C plate 22b are laminated, for example, via an adhesive layer not shown.

The second λ/4 member 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 λ/4 member is preferably 0.9 to 3, more preferably 0.9 to 2.5, even more preferably 0.9 to 1.5, and particularly preferably 0.9 to 1.3.

The second λ/4 member is formed of any suitable material that can satisfy the above characteristics. The second λ/4 member can be, for example, a stretched resin film or an oriented and solidified layer of a liquid crystal compound.

Examples of resins contained in the resin film include polycarbonate-based resins, polyester carbonate-based resins, polyester-based resins, polyvinyl acetal-based resins, polyarylate-based resins, cyclic olefin-based resins, cellulose-based resins, polyvinyl alcohol-based resins, polyamide-based resins, polyimide-based resins, polyether-based resins, polystyrene-based resins, acrylic-based resins, and the like. These resins may be used alone or in combination. Examples of methods for combining include blending and copolymerization. When the second λ/4 member 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.

Any suitable polycarbonate-based resin can be used as the polycarbonate-based resin. 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 second λ/4 member and methods for forming the second λ/4 member are described, for example, in JP 2014-10291 A, JP 2014-26266 A, JP 2015-212816 A, JP 2015-212817 A, and JP 2015-212818 A, and the descriptions in these publications are incorporated herein by reference.

The thickness of the second λ/4 member, which is made of a stretched resin film, is, for example, 10 μm to 100 μm, preferably 10 μm to 70 μm, and more preferably 20 μm to 60 μm.

The above-mentioned alignment solidified layer of the liquid crystal compound 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 second λ/4 member, typically, rod-shaped liquid crystal compounds are aligned in the slow axis direction of the second λ/4 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 in, for example, 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 second λ/4 member consisting of the liquid crystal alignment solidification layer is, for example, 1 μm to 10 μm, preferably 1 μm to 8 μm, more preferably 1 μm to 6 μm, and even more preferably 1 μm to 4 μm.

The thickness direction retardation Rth(550) of the positive C plate is preferably -50 nm to -300 nm, more preferably -70 nm to -250 nm, even more preferably -90 nm to -200 nm, and 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 retardation Re(550) of the positive C plate is, for example, less than 10 nm.

The positive C plate may be made of any suitable material, but is preferably made of a film containing a liquid crystal material fixed in homeotropic alignment. The liquid crystal material (liquid crystal compound) that can be homeotropically aligned may be a liquid crystal monomer or a liquid crystal polymer. Specific examples of such liquid crystal compounds and methods for forming a positive C plate include the liquid crystal compounds and methods for forming the retardation layer described in [0020] to [0028] of JP-A-2002-333642. In this case, the thickness of the positive C plate is preferably 0.5 μm to 5 μm.

The first protective member typically includes a substrate. The thickness of the substrate is preferably 5 μm to 80 μm, more preferably 10 μm to 50 μm, and even more preferably 15 μm to 40 μm. The substrate may be made of any suitable film. Examples of materials that are the main components of the film that constitutes the substrate include cellulose-based resins such as triacetyl cellulose (TAC), polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, polyimide-based, polyethersulfone-based, polysulfone-based, polystyrene-based, cycloolefin-based resins such as polynorbornene, polyolefin-based, (meth)acrylic, and acetate-based resins. Here, (meth)acrylic refers to acrylic and/or methacrylic. In one embodiment, the substrate is preferably made of a (meth)acrylic resin. By using a (meth)acrylic resin, a substrate with excellent smoothness can be formed by extrusion molding. A protective member with excellent smoothness can then be obtained.

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 may be arranged so that the surface treatment layer is located on the front side. Specifically, the surface treatment layer may be located on the outermost surface of the first laminated portion. The surface treatment layer may have any appropriate function. For example, from the viewpoint of improving visibility, the surface treatment layer preferably has an anti-reflection function. The thickness of the surface treatment layer is preferably 0.5 μm to 10 μm, more preferably 1 μm to 7 μm, and even more preferably 2 μm to 5 μm.

The second laminated section 200 includes a reflective polarizing member 14 and an adhesive layer disposed between the reflective polarizing member 14 and the second lens section 24. For example, from the viewpoint of improving visibility, the second laminated section 200 further includes an absorbing polarizing member 28 disposed between the reflective polarizing member 14 and the second lens section 24. The absorbing polarizing member 28 is laminated in front of the reflective polarizing member 14 via an adhesive layer 44. The reflection axis of the reflective polarizing member 14 and the absorption axis of the absorbing polarizing member 28 can be disposed approximately parallel to each other, and the transmission axis of the reflective polarizing member 14 and the transmission axis of the absorbing polarizing member 28 can be disposed approximately parallel to each other. By laminating them via an adhesive layer, the reflective polarizing member 14 and the absorbing polarizing member 28 are fixed, and it is possible to prevent the axial arrangement of the reflection axis and the absorption axis (the transmission axis and the transmission axis) from being misaligned. In addition, it is possible to suppress the adverse effects of an air layer that may be formed between the reflective polarizing member 14 and the absorbing polarizing member 28.

The second laminate 200 further includes a second protective member 32 disposed behind the reflective polarizing member 14. The second protective member 32 is laminated to the reflective polarizing member 14 via an adhesive layer 43. The second protective member 32 may be located on the outermost surface of the second laminate 200. The second protective member may include a substrate, as with the first protective member. The second protective member preferably includes a substrate and a surface treatment layer formed on the substrate. In this case, the surface treatment layer may be located on the outermost surface of the second laminate. For details of the substrate and the surface treatment layer, the same explanation as for the first protective member may be applied.

2, the second laminate 200 may further include a third phase difference member 30 disposed between the absorbing polarizing member 28 and the second lens section 24. The third phase difference member 30 is laminated to the absorbing polarizing member 28 via an adhesive layer 45. The third phase difference member 30 is laminated to the second lens section 24 via an adhesive layer 46, and the second laminate 200 is integrally provided to the second lens section 24. The third phase difference member 30 includes, for example, a third λ/4 member. The angle between the absorption axis of the absorbing polarizing 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 about 45°. By providing such a member, for example, reflection of external light from the second lens section 16 side can be prevented. When the third phase difference member does not include any member other than the third λ/4 member, the third phase difference member may correspond to the third λ/4 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 in other polarization states. A typical reflective polarizing element is made of a film (sometimes called a reflective polarizing film) with a multilayer structure. In this case, the thickness of the reflective polarizing element is, for example, 10 μm to 150 μm, preferably 20 μm to 100 μm, and more preferably 30 μm to 60 μm.

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

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

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

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

The crossed transmittance, single transmittance and degree of polarization can be measured, for example, using an ultraviolet-visible spectrophotometer. The degree of polarization P can be calculated by measuring the single transmittance Ts, parallel transmittance Tp and crossed transmittance Tc using an ultraviolet-visible spectrophotometer, and using the obtained Tp and Tc, according to the following formula. Note that Ts, Tp and Tc are Y values measured using a 2-degree visual field (C light source) according to JIS Z 8701 and corrected for visibility.
Degree of polarization P(%)={(Tp-Tc)/(Tp+Tc)} ^1/2 × 100

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.

The in-plane retardation Re(550) of the third λ/4 member 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 third λ/4 member preferably exhibits an inverse dispersion wavelength characteristic in which the retardation value increases according to the wavelength of the measurement light. The Re(450)/Re(550) of the third λ/4 member may be, for example, 0.75 or more and less than 1, or 0.8 or more and 0.95 or less. The third λ/4 member preferably exhibits a refractive index characteristic 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, even more preferably 0.9 to 1.5, and particularly preferably 0.9 to 1.3.

The third λ/4 member is formed of any suitable material that can satisfy the above characteristics. The third λ/4 member 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 second λ/4 member can be applied to the third λ/4 member composed of a stretched resin film or an oriented and solidified layer of a liquid crystal compound. The second λ/4 member and the third λ/4 member may be members having the same configuration (e.g., forming material, thickness, optical properties, etc.) or may be members having different configurations.

In the example shown in FIG. 2, six adhesive layers 41 to 46 are used to integrally provide each member disposed between the first lens portion 16 and the second lens portion 24 with the first lens portion 16 or the second lens portion 24. In the example shown in FIG. 2, the total number of adhesive layers contained in the first laminated portion 100 and the second laminated portion 200 is six layers. For example, the number of adhesive layers varies depending on the number of members disposed between the first lens portion 16 and the second lens portion 24. The total number of adhesive layers contained in the first laminated portion and the second laminated portion may be, for example, three or more layers, four or more layers, five or more layers, or six or more layers. The more adhesive layers disposed between the first lens portion 16 and the second lens portion 24, the lower the smoothness of the laminated portion. However, by having the above ISC value for the entire lens portion, excellent visibility can be achieved.

The thickness of the adhesive layer used to laminate the above-mentioned components may be set to any appropriate thickness. The thickness of each adhesive layer used to laminate the above-mentioned components is preferably 20 μm or less, and may be 15 μm or less, 10 μm or less, or 7 μm or less. With such a thickness, the degree of unevenness on the adhesive layer surface can be suppressed, and the ISC value of the entire lens portion can be satisfactorily achieved. On the other hand, the thickness of the adhesive layer is, for example, 3 μm or more.

The surface roughness Ra of each of the adhesive layers used to laminate the above members is preferably 20 nm or less, and more preferably 15 nm or less. With such a surface roughness Ra, the ISC value of the entire lens portion can be satisfactorily achieved.

The adhesive layer may be made of any suitable adhesive. Specific examples include acrylic adhesives, rubber adhesives, silicone adhesives, polyester adhesives, urethane adhesives, epoxy adhesives, and polyether adhesives. By adjusting the type, number, combination, and compounding ratio of the monomers forming the base resin of the adhesive, as well as the compounding amount of the crosslinking agent, reaction temperature, reaction time, etc., an adhesive having the desired properties according to the purpose can be prepared. The base resin of the adhesive may be used alone or in combination of two or more types. An acrylic resin is preferably used as the base resin. Specifically, the adhesive layer is preferably made of an acrylic adhesive.

For example, the adhesive layer can be formed by applying an adhesive composition containing a base resin, additives such as a crosslinking agent, and a solvent, followed by drying. The adhesive composition may be applied directly to the adherend, or may be applied to a substrate such as a separately prepared base film. Drying is typically performed by heating.

For example, the surface roughness Ra can be satisfied by adjusting the thickness of the coating film of the pressure-sensitive adhesive composition. If the film thickness is too thick, heating may cause liquid flow in the coating film due to temperature differences, resulting in the formation of a pressure-sensitive adhesive layer with a large degree of surface unevenness.

For example, the surface roughness Ra can be satisfied by controlling the drying conditions of the coating film of the adhesive composition. Specifically, the surface roughness Ra can be satisfied by adjusting the volume and speed of the air blown onto the coating film during drying. If the volume and speed of the air blown onto the coating film are too large, waves may occur in the coating film, and an adhesive layer with a large degree of surface unevenness may be formed. In one embodiment, the coating film is preferably dried in a temperature environment of 65°C to 110°C with an air speed adjusted to within a range of 2 m/min to 15 m/min, and more preferably adjusted to 2 m/min to 8 m/min. For example, it is preferable that the temperature and air speed are adjusted to such values near the entrance of the oven in which drying is performed after coating. Specifically, the temperature and air speed can be adjusted to such values from the entrance of the oven to the center of the oven.

It is preferable that each of the adhesive layers used to laminate the above-mentioned members is composed of a single layer. For example, it is preferable that each of the adhesive layers does not have a multi-layer structure formed by applying the adhesive composition two or more times. By having the adhesive layer composed of a single layer, for example, it is possible to satisfy the above-mentioned surface roughness Ra.

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. The thickness, surface roughness Ra and retardation value were measured by the following measuring methods.
<Thickness>
The thickness of 10 μm or less was measured using a scanning electron microscope (manufactured by JEOL Ltd., product name "JSM-7100F"), and the thickness of more than 10 μm was measured using a digital micrometer (manufactured by Anritsu Corporation, product name "KC-351C").
<Surface roughness Ra>
The arithmetic mean surface roughness Ra (μm) was measured according to JIS B 0601 (1994 edition).
The adhesive layer to be measured was attached to a glass plate (manufactured by MATSUNAMI, MICRO SLIDE GLASS, product number S, thickness 1.3 mm, 45 mm x 50 mm) to prepare a measurement sample. The adhesive layer was attached by transferring the adhesive layer formed on the substrate film from the substrate film to the glass plate. The obtained measurement sample was measured using a scanning white light interferometer (manufactured by Zygo, product name "Newview7300"). Specifically, the measurement sample was placed on a measurement table with a vibration-proof table, interference fringes were generated using a single white LED illumination, and an interference objective lens (2.5 times) with a reference surface was scanned in the Z direction (thickness direction) to selectively obtain the smoothness (surface smoothness) of the outermost surface of the adhesive layer in the field of view of 2 mm □. Based on this measurement, the arithmetic average surface roughness Ra was calculated.
<Phase difference value>
The phase difference value at each wavelength at 23° C. was measured using a Mueller matrix polarimeter (manufactured by Axometrics, product name "Axoscan").

[Example 1]
(Formation of Pressure-Sensitive Adhesive Layer)
A monomer mixture containing 92 parts by weight of butyl acrylate, 2.9 parts by weight of acrylic acid, 0.1 parts by weight of 2-hydroxyethyl acrylate, and 5 parts by weight of N-acryloylmorpholine was charged into a four-neck flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a cooler. Furthermore, 0.1 parts by weight of 2,2'-azobisisobutyronitrile as a polymerization initiator was charged together with 200 parts by weight of ethyl acetate per 100 parts by weight of this monomer mixture, and nitrogen gas was introduced while gently stirring to replace the atmosphere in the flask with nitrogen. The liquid temperature in the flask was kept at about 55°C, and a polymerization reaction was carried out for 8 hours to prepare a solution of an acrylic polymer having a weight average molecular weight (Mw) of 1.78 million.
The acrylic polymer solution was applied to the substrate film, and the resulting coating film on the substrate film was dried in an oven to form a pressure-sensitive adhesive layer having a thickness of 5 μm and a surface roughness Ra of 12 nm. The drying was performed by adjusting the air speed in the oven from the oven inlet to the center of the oven within a range of 15 m/min or less. The air speed was measured by an anemometer installed in the oven.

(Fabrication of λ/4 Members)
Polymerization was carried out using a batch polymerization apparatus consisting of two vertical reactors equipped with stirring blades and a reflux condenser controlled at 100°C. 29.60 parts by mass (0.046 mol) of bis[9-(2-phenoxycarbonylethyl)fluoren-9-yl]methane, 29.21 parts by mass (0.200 mol) of isosorbide (ISB), 42.28 parts by mass (0.139 mol) of spiroglycol (SPG), 63.77 parts by mass (0.298 mol) of diphenyl carbonate (DPC), and 1.19 x 10 ^-2 parts by mass (6.78 x 10 ^-5 mol) of calcium acetate monohydrate as a catalyst were charged. After the inside of the reactor was replaced with nitrogen under reduced pressure, it was heated with a heat medium, and stirring was started when the inside temperature reached 100°C. The internal temperature was allowed to reach 220°C 40 minutes after the start of the temperature rise, and the pressure was controlled to maintain this temperature while simultaneously starting decompression, and the pressure was reduced to 13.3 kPa in 90 minutes after reaching 220°C. Phenol vapor by-produced during the polymerization reaction was led to a reflux condenser at 100°C, a small amount of monomer components contained in the phenol vapor were returned to the reactor, and uncondensed phenol vapor was led to a condenser at 45°C and recovered. Nitrogen was introduced into the first reactor to restore the pressure to atmospheric pressure once, and the oligomerized reaction liquid in the first reactor was transferred to the second reactor. Next, the temperature rise and decompression in the second reactor were started, and the internal temperature was set to 240°C and the pressure to 0.2 kPa in 50 minutes. Thereafter, polymerization was allowed to proceed until a predetermined stirring power was reached. Nitrogen was introduced into the reactor at the time the predetermined power was reached to restore the pressure, and the polyester carbonate resin produced was extruded into water, and the strands were cut to obtain pellets.

The obtained polyester carbonate resin (pellets) was vacuum dried at 80°C for 5 hours, and then a long resin film with a thickness of 135 μm was produced using a film-making 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: 120-130°C) and a winder. 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 with 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.

(Formation of a positive C plate)
A liquid crystal coating liquid was prepared by dissolving 20 parts by weight of a side-chain liquid crystal polymer represented by the following chemical formula (1) (the numbers 65 and 35 in the formula indicate the mol% of the monomer unit, and are conveniently expressed as a block polymer: weight average molecular weight 5000), 80 parts by weight of a polymerizable liquid crystal exhibiting a nematic liquid crystal phase (manufactured by BASF: trade name Paliocolor LC242), and 5 parts by weight of a photopolymerization initiator (manufactured by Ciba Specialty Chemicals: trade name Irgacure 907) in 200 parts by weight of cyclopentanone. Then, the coating liquid was applied to a PET substrate that had been subjected to a vertical alignment treatment using a bar coater, and the liquid crystal was aligned by heating and drying at 80°C for 4 minutes. This liquid crystal layer was irradiated with ultraviolet light to harden the liquid crystal layer, thereby forming a positive C plate having a thickness of 4 μm and an Rth (550) of −100 nm on the substrate.

(Preparation of protective member)
The following hard coat layer-forming material was applied to an acrylic film (thickness 40 μm) having a lactone ring structure, and heated at 90° C. for 1 minute. After heating, the coating layer was irradiated with ultraviolet light from a high-pressure mercury lamp at an integrated light quantity of 300 mJ/ ^cm2 to harden the coating layer, thereby producing an acrylic film (thickness 44 μm) on which a hard coat layer having a thickness of 4 μm was formed.
Next, the following coating solution A for forming an antireflection layer was applied onto the hard coat layer using a wire bar, and the applied coating solution was heated at 80° C. for 1 minute and dried to form a coating film. The dried coating film was irradiated with ultraviolet light from a high-pressure mercury lamp at an integrated light quantity of 300 mJ/cm ² to cure the coating film, forming an antireflection layer A having a thickness of 140 nm.
Next, the following coating solution B for forming an antireflection layer was applied onto the antireflection layer A using a wire bar, and the applied coating solution was heated at 80° C. for 1 minute and dried to form a coating film. The dried coating film was irradiated with ultraviolet rays from a high-pressure mercury lamp at an integrated light quantity of 300 mJ/ ^cm2 to cure the coating film, thereby forming an antireflection layer B having a thickness of 105 nm.
In this way, a protective member (thickness: 44 μm) was obtained.

(Hard Coat Layer Forming Material)
A hard coat layer-forming material was prepared by mixing 50 parts of a urethane acrylic oligomer (manufactured by Shin-Nakamura Chemical Co., Ltd., "NK Oligo UA-53H"), 30 parts of a multifunctional acrylate mainly composed of pentaerythritol triacrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., product name "Viscoat #300"), 20 parts of 4-hydroxybutyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd.), 1 part of a leveling agent (manufactured by DIC Corporation, "GRANDIC PC4100") and 3 parts of a photopolymerization initiator (manufactured by Ciba Japan KK, "Irgacure 907") and diluting with methyl isobutyl ketone to a solids concentration of 50%.

(Anti-reflection layer forming coating solution A)
100 parts by weight of a multifunctional acrylate (manufactured by Arakawa Chemical Industries, Ltd., product name "Opstar KZ6728", solid content 20% by weight), 3 parts by weight of a leveling agent (manufactured by DIC Corporation, product name "GRANDIC PC4100"), and 3 parts by weight of a photopolymerization initiator (manufactured by BASF Corporation, product name "OMNIRAD907", solid content 100% by weight) were mixed. The mixture was diluted with butyl acetate as a diluting solvent to a solid content of 12% by weight, and the mixture was stirred to prepare coating solution A for forming an antireflection layer.

(Anti-reflection layer forming coating solution B)
100 parts by weight of a polyfunctional acrylate containing pentaerythritol triacrylate as a main component (manufactured by Osaka Organic Chemical Industry Co., Ltd., product name "Viscoat #300", solid content 100% by weight), 150 parts by weight of hollow nanosilica particles (manufactured by JGC Catalysts and Chemicals Co., Ltd., product name "Surulia 5320", solid content 20% by weight, weight average particle diameter 75 nm), 50 parts by weight of solid nanosilica particles (manufactured by Nissan Chemical Industries, Ltd., product name "MEK-2140Z-AC", solid content 30% by weight, weight average particle diameter 10 nm), 12 parts by weight of a fluorine-containing additive (manufactured by Shin-Etsu Chemical Co., Ltd., product name "KY-1203", solid content 20% by weight), and 3 parts by weight of a photopolymerization initiator (manufactured by BASF, product name "OMNIRAD907", solid content 100% by weight) were mixed. To the mixture was added a mixed solvent of TBA (tertiary butyl alcohol), MIBK (methyl isobutyl ketone) and PMA (propylene glycol monomethyl ether acetate) in a weight ratio of 60:25:15 as a dilution solvent so that the total solid content was 4% by weight, and the mixture was stirred to prepare coating solution B for forming an anti-reflection layer.

(First laminated portion)
The positive C plate was attached to the λ/4 member (stretched film) via an ultraviolet-curing adhesive (thickness after curing: 1 μm) to obtain a retardation member.
The obtained retardation member was attached to a glass plate (manufactured by MATSUNAMI, MICRO SLIDE GLASS, product number S, thickness 1.3 mm, 180 mm x 250 mm) via the above-mentioned 5 μm thick adhesive layer. Here, the retardation member was attached so that the positive C plate was located on the glass plate side.
Next, the protective member was attached to the retardation member via the 5 μm-thick adhesive layer to obtain a first laminated portion on the glass plate. Here, the acrylic film of the protective member was attached to the retardation member side.

(Preparation of Absorptive Polarizing Film)
The thermoplastic resin substrate used was a long amorphous isophthalic copolymerized polyethylene terephthalate film (thickness: 100 μm) having a water absorption rate of 0.75% and a Tg of about 75° C. One side of the resin substrate was subjected to a corona treatment.
A PVA aqueous solution (coating solution) was prepared by adding 13 parts by weight of potassium iodide to 100 parts by weight of a PVA-based resin prepared by mixing polyvinyl alcohol (polymerization degree 4,200, saponification degree 99.2 mol%) and acetoacetyl-modified PVA (manufactured by Mitsubishi Chemical Corporation, product name "GOHSENEX Z410") in a ratio of 9:1, and dissolving the resultant in water.
The above PVA aqueous solution was applied to the corona-treated surface of a resin substrate and dried at 60° C. to form a PVA-based resin layer having a thickness of 13 μm, thereby producing a laminate.
The obtained laminate was uniaxially stretched at its free end to 2.4 times its original size in the machine direction (longitudinal direction) between rolls having different peripheral speeds in an oven at 130° C. (auxiliary air stretching treatment).
Next, the laminate was immersed in an insolubilizing bath (a boric acid aqueous solution obtained by mixing 4 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 40° C. for 30 seconds (insolubilizing treatment).
Next, the film was immersed in a dye bath (an aqueous iodine solution obtained by mixing iodine and potassium iodide in a weight ratio of 1:7 with respect to 100 parts by weight of water) having a liquid temperature of 30° C. for 60 seconds while adjusting the concentration so that the single transmittance (Ts) of the finally obtained polarizing film would be 42.0% or more (dyeing treatment).
Next, the plate was immersed in a crosslinking bath (a boric acid aqueous solution obtained by mixing 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 40° C. for 30 seconds (crosslinking treatment).
Thereafter, the laminate was immersed in an aqueous boric acid solution (boric acid concentration: 4 wt %, potassium iodide concentration: 5 wt %) at a liquid temperature of 70° C., and uniaxially stretched in the longitudinal direction (longitudinal direction) between rolls with different peripheral speeds to a total stretch ratio of 5.5 times (underwater stretching treatment).
Thereafter, the laminate was immersed in a cleaning bath (an aqueous solution obtained by mixing 4 parts by weight of potassium iodide with 100 parts by weight of water) at a liquid temperature of 20° C. (cleaning treatment).
Thereafter, while drying in an oven maintained at 90° C., the laminate was brought into contact with a SUS heated roll having a surface temperature maintained at 75° C. for about 2 seconds (drying shrinkage treatment). The shrinkage rate of the laminate in the width direction due to the drying shrinkage treatment was 5.2%.
In this manner, a polarizing film (absorption type polarizing film) having a thickness of 5 μm was formed on the resin substrate.

(Second laminated portion)
The absorptive polarizing film was attached to a glass plate (manufactured by MATSUNAMI, MICRO SLIDE GLASS, product number S, thickness 1.3 mm, 180 mm×250 mm) via the above-mentioned 5 μm-thick adhesive layer.
Next, a reflective polarizing film ("APCF" manufactured by Nitto Denko Corporation) was attached to the absorptive polarizing film via the above-mentioned 5 μm-thick adhesive layer such that the reflection axis of the reflective polarizing film and the absorption axis of the absorptive polarizing film were arranged parallel to each other.
Next, the protective member was attached to the reflective polarizing film to obtain a second laminate on the glass plate, with the acrylic film of the protective member facing the reflective polarizing film.

[Example 2]
A first laminate part and a second laminate part were obtained in the same manner as in Example 1, except that the pressure-sensitive adhesive layer shown below was used.
(Formation of Pressure-Sensitive Adhesive Layer)
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 was charged into a four-neck flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a cooler. Furthermore, 0.3 parts by weight of dibenzoyl peroxide as a polymerization initiator was charged together with ethyl acetate for 100 parts by weight of this monomer mixture, and nitrogen gas was introduced while gently stirring to replace the atmosphere in the flask with nitrogen. The liquid temperature in the flask was kept at 60°C and a polymerization reaction was carried out for 7 hours. Next, ethyl acetate was added to the obtained reaction liquid to adjust the solid concentration to 30% by weight, and a solution of an acrylic polymer having a weight average molecular weight (Mw) of 2.2 million was prepared.
An acrylic adhesive was prepared by blending 0.6 parts by weight of a trimethylolpropane/tolylene diisocyanate adduct (product name: Coronate L, manufactured by Tosoh Corporation) and 0.075 parts by weight of a silane coupling agent (product name: KBM403, manufactured by Shin-Etsu Chemical Co., Ltd.) with 100 parts by weight of the solid content of the obtained acrylic polymer solution.
The obtained acrylic adhesive was applied to a substrate film, and the coating film on the substrate film was dried in an oven to form an adhesive layer having a thickness of 15 μm and a surface roughness Ra of 16 nm. The drying was performed by adjusting the air speed in the oven from the oven inlet to the center of the oven to a range of 15 m/min or less.

[Comparative Example 1]
In forming the adhesive layer, the air speed in the oven was adjusted to within a range of 15 m/min or less, and an adhesive layer having a thickness of 15 μm and a surface roughness Ra of 22 nm was obtained. The first laminate part and the second laminate part were obtained in the same manner as in Example 2, except that.

[Comparative Example 2]
The first laminate part and the second laminate part were obtained in the same manner as in Example 2, except that in forming the adhesive layer, the coating thickness of the acrylic adhesive was changed and the air speed in the oven was adjusted to within a range of 15 m/min or less to obtain an adhesive layer having a thickness of 23 μm and a surface roughness Ra of 29 nm.

For the examples and comparative examples, the ISC value was measured using EyeScale-4W manufactured by I-System Co., Ltd. Specifically, based on the specifications of the measuring device, the in-plane unevenness of the first laminated portion and the second laminated portion was calculated as the ISC value in the ISC measurement mode of the 3CCD image sensor.
Fig. 4 is a diagram for explaining a method for measuring the ISC value, and is a schematic diagram showing the arrangement of a light source, a measurement sample, a screen, and a CCD camera as viewed from above. As shown in Fig. 4, a light source L, a first laminated unit 100, a second laminated unit 200, and a screen S were arranged in this order, and a transmitted image projected onto the screen S was measured by a CCD camera C.
The first laminated part 100 and the second laminated part 200, which are the measurement samples, were arranged with a gap of 0.001 to 3 mm so that the protective members of each were facing each other (the first laminated part 100 was arranged so that the adjacent glass plate G was located on the light source L side, and the second laminated part 200 was arranged so that the adjacent glass plate G was located on the screen S side). The distance from the light source L to the measurement sample in the X-axis direction was 10 to 60 cm. The distance from the light source L to the screen S in the X-axis direction was 70 to 130 cm. The distance from the CCD camera C to the measurement sample in the Y-axis direction was 3 to 30 cm. The distance from the CCD camera C to the screen S in the X-axis direction was 70 to 130 cm.
For ease of understanding, the details of the first and second laminated portions are omitted in Fig. 4. The measurement results are shown in Table 1.

For the examples and comparative examples, appearance (light transmitted through the lens) was evaluated using an optical lens (manufactured by Thorabs, product name "LA1145") and a point light source (manufactured by Hamamatsu Photonics, model number "L8425-01").
Specifically, the first laminated part and the second laminated part cut into a circle of 45 mmφ were laminated in this order on the flat side of the optical lens while being lightly pressed with a hand roller so as not to introduce foreign matter, air bubbles, or deformation streaks into the surface. Next, in order to remove the influence of minute air bubbles, degassing was performed using a pressurized degassing device (autoclave). The degassing conditions were 50°C, 0.5 MPa, and 30 minutes. After degassing, the sample was allowed to cool at room temperature for 30 minutes or more to obtain a measurement sample.
A point light source, an optical lens (a measurement sample), and a screen were placed in this order, and the light from the point light source through the optical lens was projected onto the screen to evaluate its appearance. Here, the lens was held by a holder at a position where the light from the point light source was incident from the convex side of the optical lens. The distance from the point light source to the screen was 1050 mm, and the distance from the optical lens to the screen was 130 mm.
The light projected on the screen through the optical lens was visually observed, and the appearance was evaluated according to the following evaluation criteria. The measurement results are shown in Table 1.
(Evaluation criteria)
・Good: No visible wrinkles or ripples ・Poor: Visible wrinkles and ripples

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

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

2 Display system, 4 Lens section, 12 Display element, 14 Reflective polarizing member, 16 First lens section, 18 Half mirror, 20 First phase difference member, 22 Second phase difference member, 24 Second lens section, 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, 100 First laminate section, 200 Second laminate section.

Claims (13)

1. A lens unit for use in a display system for displaying an image to a user, comprising:
a reflective polarizing member that reflects light that is emitted forward from a display surface of a display element that displays an image and that has passed through the polarizing member and the first λ/4 member;
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, the half mirror transmitting light emitted from the display element and reflecting light reflected by the reflective polarizing member toward the reflective polarizing member;
A second lens portion disposed in front of the reflective polarizing member;
a second λ/4 member disposed on an optical path between the half mirror and the reflective polarizing member;
The ISC value of a first laminate including the second λ/4 member and at least one pressure-sensitive adhesive layer and a second laminate including the reflective polarizing member and at least one pressure-sensitive adhesive layer is 100 or less.
Lens part. The lens section according to claim 1, wherein the second laminate section includes an absorptive polarizing member disposed between the reflective polarizing member and the second lens section. The lens section according to claim 1, wherein the second laminate section includes a third λ/4 member disposed between the reflective polarizing member and the second lens section. The lens portion according to claim 1, wherein the first laminate portion and the second laminate portion are disposed at a distance from each other. The lens section according to claim 1, wherein the second laminate section includes a second protective member disposed behind the reflective polarizing member. The lens section according to claim 1, wherein the first laminate section includes a first protective member disposed in front of the second λ/4 member. The lens portion according to claim 1, wherein the total number of adhesive layers included in the first laminate and the second laminate is three or more. The lens portion according to claim 1, wherein the thickness of each of the adhesive layer included in the first laminate and the adhesive layer included in the second laminate is 20 μm or less. The lens portion according to claim 1, wherein the surface roughness Ra of each of the adhesive layer included in the first laminate and the adhesive layer included in the second laminate is 20 nm or less. The lens portion according to claim 1, wherein each of the adhesive layer included in the first laminate and the adhesive layer included in the second laminate is a single layer. The lens unit according to claim 1, wherein the first lens unit and the half mirror are integral. A display having a lens portion according to any one of claims 1 to 11. A step of passing light representing an image outputted through the polarizing member and the first λ/4 member through a half mirror and a first lens unit;
A step of passing the light that has passed through the half mirror and the first lens portion through a second λ/4 member;
A step of reflecting the light that has passed through the second λ/4 member toward the half mirror by a reflective polarizing member;
allowing the light reflected by the reflective polarizing member and the half mirror to pass through the reflective polarizing member by the second λ/4 member;
and passing the light transmitted through the reflective polarizing member through a second lens portion.
The ISC value of a first laminate including the second λ/4 member and at least one pressure-sensitive adhesive layer and a second laminate including the reflective polarizing member and at least one pressure-sensitive adhesive layer is 100 or less.
Display method.

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