CN116997951A

CN116997951A - Display device

Info

Publication number: CN116997951A
Application number: CN202280021956.2A
Authority: CN
Inventors: 高月瑛
Original assignee: Sumitomo Chemical Co Ltd
Current assignee: Sumitomo Chemical Co Ltd
Priority date: 2021-06-23
Filing date: 2022-06-16
Publication date: 2023-11-03

Abstract

The invention provides a display device (1) capable of suppressing reflected light reflected by a high refractive index layer (45) from entering a light receiving sensor (42), and further provides an optical laminate (51) used in the display device (1). A display device (1) of the present invention comprises, in order from the visible side, a high refractive index layer (42), a 1 st retardation layer (31), a linear polarization layer (11), and a display unit (40). The refractive index of the high refractive index layer (42) is 1.60 or more. The display unit (40) has a display element (41) and a light receiving sensor (42). A1 st phase difference layer (31) and a linear polarization layer (11) are laminated so as to cover the display element (41) and the light receiving sensor (42).

Description

Display device

Technical Field

The present invention relates to a display device and an optical laminate used in the display device.

Background

Polarizing plates including a linear polarizing layer are widely used as a polarizing light supply element for display devices such as liquid crystal display devices and organic Electroluminescence (EL) display devices, as a polarizing light detection element, and as an element for suppressing the emission of reflected light reflected by a display element to the outside. Display devices having polarizing plates have also been developed to mobile devices such as notebook personal computers, smart phones, tablet terminals, and the like. Patent document 1 describes that, from the viewpoints of expansion of a display area of a display surface of a mobile device such as a smart phone and design, for example, an outer edge of the display area is recessed in a plan view to provide a non-display area.

In the non-display region having a concave shape, a display element and a polarizing plate are not generally disposed. Therefore, by disposing various sensors such as a camera lens and a light receiving sensor in the non-display region, adverse effects on the camera performance and the sensitivity of the sensors can be reduced.

Prior art literature

Patent literature

Patent document 1: japanese patent application laid-open No. 2019-219528

Disclosure of Invention

Problems to be solved by the invention

In order to further enlarge the display area of the display surface, it is required to reduce the non-display area. In this case, it is conceivable to dispose various sensors such as a light receiving sensor in a display region where a display element and a polarizing plate are provided. When the light receiving sensor is disposed in the display region, the light emitted from the display element is easily reflected by the high refractive index layer disposed on the visible side of the polarizing plate and enters the light receiving sensor. Reflected light entering the light receiving sensor is likely to cause malfunction of the light receiving sensor.

The present invention aims to provide a display device and an optical laminate used in the display device, which can inhibit reflected light reflected by a high refractive index layer from entering a light receiving sensor even if the high refractive index layer is arranged on a visual side.

Means for solving the problems

The present invention provides the following display device.

[ 1 ] A display device comprising, in order from the visible side, a high refractive index layer, a 1 st retardation layer, a linear polarization layer, and a display unit,

the high refractive index layer has a refractive index of 1.60 or more,

the display unit has a display element and a light receiving sensor,

the 1 st phase difference layer and the linear polarization layer are laminated so as to cover the display element and the light receiving sensor.

The display device according to [ 2 ], wherein the 1 st retardation layer covers the entire visible side of the linear polarization layer in a plan view.

The display device according to [ 1 ] or [ 2 ], wherein the transmittance of the visibility-correcting monomer of the linearly polarizing layer is 42% or more.

The display device according to any one of [ 1 ] to [ 3 ], wherein an angle formed between a slow axis of the 1 st retardation layer and an absorption axis of the linear polarization layer is 10 DEG to 80 deg.

The display device according to any one of [ 1 ] to [ 4 ], wherein an in-plane phase difference value at a wavelength of 550nm of the 1 st phase difference layer is 80nm or more and 170nm or less.

The display device according to item [ 6 ], wherein the 1 st retardation layer has inverse wavelength dispersibility.

The display device according to [ 5 ] or [ 6 ], further comprising a 2 nd retardation layer between the high refractive index layer and the linear polarization layer,

the 2 nd phase difference layer is laminated so as to cover the display element and the light receiving sensor,

the 2 nd phase difference layer has a thickness direction phase difference value of-140 nm to-20 nm at a wavelength of 550 nm.

The display device according to any one of [ 1 ] to [ 7 ], wherein a stimulus value Y of reflected light when the light emitted from the display element is reflected by the high refractive index layer is 3.45% or more and 4.54% or less.

The display device according to any one of [ 1 ] to [ 8 ], wherein the light receiving sensor is capable of detecting light having a wavelength of 320nm to 4000 nm.

The display device according to any one of [ 1 ] to [ 9 ], wherein the light emitted from the display element is light having a wavelength of 320nm to 4000 nm.

The display device according to any one of [ 1 ] to [ 10 ], further comprising a 3 rd retardation layer between the linear polarization layer and the display unit.

The present invention provides the following optical layered body.

[ 12 ] an optical laminate comprising, in order, a high refractive index layer, a 1 st retardation layer and a linear polarization layer,

the refractive index of the high refractive index layer is 1.60 or more.

The optical laminate according to item [ 13 ], wherein the 1 st retardation layer covers the entire surface of the linear polarization layer on the visible side in a plan view.

The optical laminate according to [ 12 ] or [ 13 ], wherein the visibility-modifying monomer transmittance of the linearly polarizing layer is 42% or more.

The optical laminate according to [ 12 ] or [ 13 ], wherein an angle between a slow axis of the 1 st retardation layer and an absorption axis of the linear polarization layer is 10 DEG to 80 deg.

The optical laminate according to [ 12 ] or [ 13 ], wherein the in-plane phase difference value at 550nm of the wavelength of the 1 st phase difference layer is 80nm or more and 170nm or less.

The optical laminate according to [ 12 ] or [ 13 ], wherein the 1 st retardation layer has inverse wavelength dispersibility.

The optical laminate according to [ 12 ] or [ 13 ], further comprising a 2 nd retardation layer between the high refractive index layer and the linear polarization layer,

The optical laminate according to [ 19 ] or [ 13 ], wherein the linear polarization layer further has a 3 rd retardation layer on the side opposite to the 1 st retardation layer side.

Effects of the invention

According to the display device of the present invention, the reflected light reflected by the high refractive index layer can be suppressed from entering the light receiving sensor. Further, according to the optical laminate of the present invention, the display device of the present invention can be provided.

Drawings

Fig. 1 is a schematic cross-sectional view schematically showing a display device according to an embodiment of the present invention.

Fig. 2 is a schematic cross-sectional view schematically showing a display device according to another embodiment of the present invention.

Fig. 3 is a schematic cross-sectional view schematically showing a display device according to still another embodiment of the present invention.

Fig. 4 is a schematic cross-sectional view schematically showing a display device according to still another embodiment of the present invention.

Detailed Description

Hereinafter, preferred embodiments of the display device and the optical laminate will be described with reference to the drawings. In each of the drawings, the same members as those described above are denoted by the same reference numerals, and description thereof will be omitted.

Embodiment 1

(display device and optical laminate)

Fig. 1 and 2 are schematic cross-sectional views schematically showing a display device according to an embodiment of the present invention. In fig. 1 and 2, the upper side is the visible side. As shown in fig. 1 and 2, the display devices 1 and 2 of the present embodiment include a high refractive index layer 45, a 1 st retardation layer 31, a linear polarization layer 11, and a display unit 40 in this order from the viewing side. Among them, the high refractive index layer 45, the 1 st retardation layer 31, and the linear polarization layer 11 constitute optical stacks 51 and 52. The refractive index of the high refractive index layer 45 is 1.60 or more, preferably 1.75 or more, more preferably 1.80 or more, and generally 2.70 or less, preferably 2.40 or less, more preferably 2.30 or less, and further preferably 2.10 or less. The refractive index of the high refractive index layer 45 can be measured by the method described in examples described later.

The display unit 40 has a display element 41 and a light receiving sensor 42. As shown in fig. 1 and 2, the display unit 40 may have a structure in which the light receiving sensor 42 is laminated on the visible side of the display element 41, or may have a structure in which the light receiving sensor 42 is laminated on the side opposite to the visible side of the display element 41. Alternatively, the light receiving sensor 42 may be fitted into a through hole or a recess provided in the display element 41. In the display unit 40, since the area of the display element 41 can be set as the display area of the display devices 1 and 2, from the viewpoint of enlarging the display area, it is preferable that the area of the display element 41 exists so as to surround the periphery of the light receiving sensor 42 in a plan view of the display unit 40.

In the display devices 1 and 2, the 1 st retardation layer 31 and the linear polarization layer 11 are laminated so as to cover the display element 41 and the light receiving sensor 42. The 1 st retardation layer 31 and the linear polarization layer 11 are preferably laminated so as to cover the entire surface on the viewing side of the display unit 40, that is, the entire surface on the viewing side of the display element 41 and the light receiving sensor 42. By providing the linear polarization layer 11 as described above, the area of the display element 41 around the light receiving sensor 42 is covered with the linear polarization layer 11 in a plan view, and thus the display area of the display devices 1 and 2 can be easily enlarged. The 1 st retardation layer 31 may be laminated so as to cover the display element 41 and the light receiving sensor 42, or may cover the entire linearly polarized layer 11 or a part thereof in a plan view. The planar shape of the 1 st retardation layer 31 may be the same as or different from the planar shape of the linear polarization layer 11.

In the display devices 1 and 2, an image is displayed by using light emitted from the display element 41. A part of the light emitted from the display element 41 may be reflected by the high refractive index layer 45 and enter the light receiving sensor 42 as indicated by an arrow in fig. 1. Particularly, in a plan view of the display unit 40, for example, when a region in which the display element 41 is disposed around the light receiving sensor 42 such as when the light receiving sensor 42 is present adjacent to a region of the display element 41, the reflected light reflected by the high refractive index layer 45 is likely to enter the light receiving sensor 42. When the reflected light enters the light receiving sensor 42, malfunction of the light receiving sensor 42 is likely to occur. In the display devices 1 and 2 of the present embodiment, the 1 st retardation layer 31 is laminated on the viewing side of the linear polarization layer 11 covering the display element 41 and the light receiving sensor 42. The reflected light reflected by the high refractive index layer 45 enters the 1 st retardation layer 31 and passes through the 1 st retardation layer 31, whereby the phase is changed. Therefore, at least a part of the reflected light passing through the 1 st phase difference layer 31 is easily absorbed by the linear polarization layer 11. This can reduce the amount of reflected light entering the light receiving sensor 42, and can suppress malfunction of the light receiving sensor 42.

The transmittance of the visibility-correcting monomer of the linearly polarizing layer 11 is preferably 42% or more, more preferably 43% or more, and may be 45% or more. When the transmittance of the visibility correction monomer of the linearly polarizing layer 11 increases, the amount of reflected light transmitted through the linearly polarizing layer 11 increases, and thus malfunction of the light receiving sensor 42 is likely to occur. According to the display devices 1 and 2 of the present embodiment, even when the linearly polarizing layer 11 having a high transmittance of the visibility correction monomer is used, the amount of reflected light entering the light receiving sensor 42 can be suppressed, and malfunction of the light receiving sensor 42 can be suppressed. The transmittance of the linearly polarized layer 11 as a visibility-correcting monomer can be measured by the method described in examples described later.

The 1 st retardation layer 31 preferably has a retardation such that the in-plane retardation value Re (550) at a wavelength of 550nm is 80nm or more and 170nm or less. The in-plane phase difference value Re (550) of the 1 st phase difference layer 31 is more preferably 100nm or more, particularly preferably 130nm or more, but may be 135nm or more, and is more preferably 160nm or less, and further preferably 150nm or less. The in-plane phase difference value Re (550) of the 1 st phase difference layer 31 can be measured by the method described in examples described later.

When the 1 st retardation layer 31 has the in-plane retardation value Re (550) within the above range, the light emitted from the display element 41 in the display device 1, 2 is converted into elliptically polarized light when passing through the 1 st retardation layer 31. The reflected light (elliptically polarized light) reflected by the high refractive index layer 45 is converted into linearly polarized light by passing through the 1 st phase difference layer 31. Accordingly, the reflected light passing through the 1 st phase difference layer 31 is easily absorbed by the linear polarization layer 11, and therefore the amount of the reflected light entering the light receiving sensor 42 can be further suppressed.

When the in-plane retardation value Re (550) of the 1 st retardation layer 31 is within the above-described range, the angle between the absorption axis of the linear polarization layer 11 and the slow axis of the 1 st retardation layer 31 is preferably within the range of 10 ° to 80 °. The angle may be 30 ° or more, and more preferably 40 ° or more. The angle may be 60 ° or less, and more preferably 50 ° or less.

The 1 st phase difference layer 31 having the in-plane phase difference value Re (550) in the above range preferably has inverse wavelength dispersibility. As a result, the wavelength range of the reflected light absorbed by the linear polarization layer 11 is widened, and therefore, the light quantity of the reflected light of various wavelengths entering the light receiving sensor 42 can be suppressed.

In the display devices 1 and 2, the stimulus value Y of the reflected light when the light emitted from the display element 41 is reflected by the high refractive index layer 45 is preferably 3.45% or more and 4.54% or less. The stimulus value Y of the reflected light is a ratio of the light intensity of the reflected light to the light intensity of the light emitted from the display element 41, and the smaller the stimulus value Y is, the smaller the light amount of the reflected light reflected by the high refractive index layer 45 is, the less likely the cause of malfunction of the light receiving sensor 42 is. The stimulus value Y of the reflected light can be measured by the method described in examples described later. The stimulus value Y of the reflected light may be 3.48% or more, 3.50% or more, or 4.30% or less, 4.10% or less, 3.90% or less, or 3.76% or less.

In the display devices 1 and 2 in which the stimulus value Y of the emitted light falls within the above-described range, the amount of reflected light entering the light receiving sensor 42 is easily suppressed. It is considered that, when the stimulus value Y of the emitted light is smaller than the above range, the refractive index of the high refractive index layer 45 is small or the transmittance of the visibility correction monomer of the linearly polarizing layer 11 is small. Therefore, in the display device in which the stimulus value Y of the emitted light is smaller than the above range, the amount of the reflected light entering the light receiving sensor 42 is small, and thus, it is considered that malfunction of the light receiving sensor 42 is less likely to occur. In addition, in the display device in which the stimulus value Y of the emitted light is larger than the above range, the amount of reflected light entering the light receiving sensor 42 is large, and malfunction of the light receiving sensor 42 is likely to occur.

(layer structure of display device and optical laminate)

Hereinafter, the display devices 1 and 2 and the optical layered bodies 51 and 52 will be described with respect to layers that may be provided other than those described above.

As shown in fig. 1 and 2, the display devices 1 and 2 and the optical stacks 51 and 52 preferably have the 1 st adhesive layer 21 between the high refractive index layer 45 and the 1 st retardation layer 31. The 1 st bonding layer 21 may be in direct contact with the high refractive index layer 45 and the 1 st retardation layer 31.

The display devices 1 and 2 and the optical stacks 51 and 52 may have a 2 nd refractive index layer (not shown) of 1 or more in addition to the high refractive index layer 45. The refractive index of the 2 nd refractive index layer may be set to the above-described refractive index range described in the high refractive index layer 45. The 2 nd refractive index layer may be provided on the visible side of the high refractive index layer 45, or may be provided between the high refractive index layer 45 and the 1 st retardation layer 31. In this case, the display devices 1 and 2 and the optical stacks 51 and 52 may have a bonding layer (an adhesive layer or an adhesive layer described later) between the high refractive index layer 45 and the 2 nd refractive index layer, and the bonding layer may be in direct contact with the high refractive index layer 45 and the 2 nd refractive index layer. In the case where the display devices 1 and 2 and the optical stacks 51 and 52 have the 2 nd refractive index layer between the high refractive index layer 45 and the 1 st retardation layer 31, the 1 st bonding layer 21 may be in direct contact with the 1 st retardation layer 31 and the 2 nd refractive index layer.

The display devices 1 and 2 and the optical laminates 51 and 52 preferably have the 2 nd adhesive layer 22 between the 1 st retardation layer 31 and the linear polarization layer 11. The 2 nd bonding layer 22 may be in direct contact with the 1 st retardation layer 31 and the linear polarization layer 11.

As shown in fig. 1 and 2, the display devices 1 and 2 and the optical stacks 51 and 52 may have a 1 st protective film 12 between the 1 st retardation layer 31 and the linear polarization layer 11. The 1 st protective film 12 may be a layer for protecting the surface of the linearly polarizing layer 11 on the viewing side, and the 1 st protective film 12 and the linearly polarizing layer 11 may constitute a linearly polarizing plate. In the case where the display devices 1 and 2 and the optical laminates 51 and 52 have the 1 st protective film 12, the 2 nd adhesive layer 22 may be in direct contact with the 1 st retardation layer 31 and the 1 st protective film 12.

In the case where the 1 st protective film 12 is provided in the display device 1, 2 and the optical laminate 51, 52, the 1 st protective film 12 and the linear polarization layer 11 may be in direct contact with each other in the display device 1, 2 and the optical laminate 51, 52, but it is preferable to provide the 3 rd bonding layer 23 between the 1 st protective film 12 and the linear polarization layer 11. The 3 rd lamination layer 23 may constitute a linear polarizing plate, and is preferably in direct contact with the 1 st protective film 12 and the linear polarizing layer 11.

The display devices 1 and 2 may have the 4 th adhesive layer 24 between the linearly polarizing layer 11 and the display unit 40 (the side of the linearly polarizing layer 11 opposite to the 1 st retardation layer 31 side). As shown in fig. 1, the linearly polarizing layer 11 and the display unit 40 may be in direct contact with the 4 th adhesive layer 24. As shown in fig. 1 and 2, the 4 th adhesive layer 24 may be provided by optical laminates 51 and 52.

The display devices 1 and 2 and the optical stacks 51 and 52 may have a 2 nd protective film (not shown) between the linearly polarizing layer 11 and the display unit 40 (the side of the linearly polarizing layer 11 opposite to the 1 st retardation layer 31 side). The 2 nd protective film may be a layer for protecting the surface of the linearly polarizing layer 11 on the side opposite to the viewing side, and the 2 nd protective film and the linearly polarizing layer 11 may constitute a linearly polarizing plate. In the case where the display devices 1 and 2 and the optical laminates 51 and 52 have the 2 nd protective film, the 2 nd protective film may be in direct contact with the linear polarization layer 11, or a bonding layer (an adhesive layer or an adhesive layer described later) may be provided between the 2 nd protective film and the linear polarization layer 11. The adhesive layer may constitute a linear polarizing plate, and is preferably in direct contact with the 2 nd protective film and the linear polarizing layer 11. In this case, the 4 th adhesive layer 24 may be provided between the 2 nd protective film and the display unit 40, or may be in direct contact with the 2 nd protective film and the display unit 40.

As shown in fig. 2, the display device 2 and the optical laminate 52 may have the 3 rd retardation layer 13 between the linear polarization layer 11 and the display unit 40 (the side of the linear polarization layer 11 opposite to the 1 st retardation layer 31 side). In this case, the display device 2 and the optical laminate 52 may have the 5 th bonding layer 25 between the linearly polarizing layer 11 and the 3 rd retardation layer 13, and the linearly polarizing layer 11 and the 3 rd retardation layer 13 may be in direct contact with the 5 th bonding layer 25. In the case where the display device 2 and the optical laminate 52 have the 2 nd protective film, the 5 th bonding layer 25 is provided between the 2 nd protective film and the 3 rd retardation layer 13, and can be in direct contact with the 2 nd protective film and the 3 rd retardation layer 13. In the display device 2 having the 3 rd retardation layer 13, the 4 th bonding layer 24 may be provided between the 3 rd retardation layer 13 and the display unit 40, or may be in direct contact with the 3 rd retardation layer 13 and the display unit 40. In the optical laminate 52 having the 3 rd retardation layer 13, the 4 th lamination layer 25 may be in direct contact with the 3 rd retardation layer 13. The linear polarization layer 11 and the 3 rd retardation layer 13 preferably constitute a circular polarization plate, and the 3 rd retardation layer 13 is preferably a λ/4 retardation layer, more preferably a λ/4 retardation layer having inverse wavelength dispersibility.

The display device 2 and the optical laminate 52 may have 1 or more 4 th retardation layers (not shown) other than the 3 rd retardation layer 13 between the linearly polarizing layer 11 and the display unit 40 (on the opposite side of the linearly polarizing layer 11 from the 1 st retardation layer 31 side). The 4 th retardation layer may be provided between the linear polarization layer 11 and the 3 rd retardation layer 13, or may be provided between the 3 rd retardation layer 13 and the display unit 40 (the side of the 3 rd retardation layer 13 opposite to the linear polarization layer 11 side). In this case, a bonding layer (an adhesive layer or an adhesive layer described later) may be provided between the 3 rd retardation layer 13 and the 4 th retardation layer, and the bonding layer may be in direct contact with the 3 rd retardation layer 13 and the 4 th retardation layer. In the case where the display device 2 and the optical laminate 52 have the 4 th retardation layer between the linear polarization layer 11 and the 3 rd retardation layer 13, the 5 th bonding layer 25 may be in direct contact with the linear polarization layer 11 and the 4 th retardation layer. In the case where the display device 2 has the 4 th retardation layer between the 3 rd retardation layer 13 and the display unit 40, the 4 th adhesive layer 24 may be in direct contact with the 4 th retardation layer and the display unit 40. In the case where the optical laminate 52 has the 3 rd retardation layer on the side opposite to the linear polarization layer 11 side of the 3 rd retardation layer 13, the 4 th retardation layer may be in direct contact with the 4 th adhesive layer. The linear polarization layer 11, the 3 rd retardation layer 13, and the 4 th retardation layer preferably constitute a circular polarization plate. The 4 th retardation layer constituting the circularly polarizing plate is preferably a lambda/2 retardation layer or a positive C layer.

Embodiment 2

Fig. 3 and 4 are schematic cross-sectional views schematically showing a display device according to another embodiment of the present invention. In fig. 3 and 4, the upper side is the visible side. The display devices 3 and 4 and the optical stacks 53 and 54 according to the present embodiment are different from the display devices 1 and 2 and the optical stacks 51 and 52 described in the previous embodiments in that the 2 nd retardation layer 32 is provided between the high refractive index layer 45 and the linear polarization layer 11, and therefore, this point will be described below.

In the display devices 3 and 4, the 2 nd retardation layer 32 is laminated so as to cover the display element 41 and the light receiving sensor 42. The 2 nd retardation layer 32 is preferably laminated so as to cover the entire surface of the display unit 40 on the viewing side, that is, the entire surface of the display element 41 and the light receiving sensor 42 on the viewing side.

The display devices 3, 4 and the optical stacks 53, 54 shown in fig. 3 and 4 have the 2 nd retardation layer 32 between the high refractive index layer 45 and the 1 st retardation layer 31. The 2 nd retardation layer 32 preferably covers the entire 1 st retardation layer 31 in plan view, and more preferably the 2 nd retardation layer 32 has the same plan view shape as the 1 st retardation layer 31.

The 2 nd retardation layer 32 may have a retardation, but preferably has a retardation of-140 nm to-20 nm in terms of the thickness direction retardation value Rth (550) at a wavelength of 550 nm. The thickness-direction retardation value Rth (550) of the 2 nd retardation layer 32 may be greater than-140 nm, or may be equal to or greater than-120 nm, or may be equal to or greater than-100 nm, or may be equal to or greater than-90 nm, or may be less than-20 nm, or may be equal to or less than-30, or may be equal to or less than-40, or may be equal to or less than-50.

The thickness direction phase difference value Rth (550) of the 2 nd phase difference layer 32 is a value calculated based on the formula (i).

Rth(550)＝[{(nx+ny)/2}-nz]×d (i)

In the formula (i) of the formula (I),

nx is the principal refractive index at a wavelength of 550nm in the plane of the 2 nd retardation layer 32,

ny is the refractive index at 550nm in the direction orthogonal to nx in the same plane as nx,

nz is a refractive index at a wavelength of 550nm in the thickness direction of the 2 nd retardation layer 32, and in the case where nx=ny, nx may be a refractive index in any direction within the plane of the 2 nd retardation layer 32,

d is the film thickness of the 2 nd retardation layer 32. ]

By providing the display devices 3 and 4 with the 2 nd phase difference layer 32, as indicated by arrows in fig. 3, the amount of light can be reduced even for reflected light entering from an oblique direction among reflected light entering the light receiving sensor 42. The reflected light entering from the oblique direction is mainly light reflected by the high refractive index layer 45 from the outgoing light emitted from the region of the display element 41 away from the light receiving sensor 42 in the plan view of the display unit 40. The amount of reflected light entering from the oblique direction is easily reduced when the thickness direction phase difference value Rth (550) of the 2 nd phase difference layer 32 is within the above range. This can further suppress malfunction of the light receiving sensor 42.

As shown in fig. 3 and 4, the 1 st bonding layer 21 may be provided between the high refractive index layer 45 and the 2 nd retardation layer 32, or may be in direct contact with the high refractive index layer 45 and the 2 nd retardation layer 32. The display devices 3 and 4 and the optical stacks 53 and 54 preferably have the 6 th bonding layer 26 between the 2 nd retardation layer 32 and the 1 st retardation layer 31, and the 2 nd retardation layer 32 and the 1 st retardation layer 31 are in direct contact with the 6 th bonding layer 26.

In the display devices 3 and 4 and the optical stacks 53 and 54 shown in fig. 3 and 4, the case where the 2 nd retardation layer 32 is provided between the high refractive index layer 45 and the 1 st retardation layer 31 has been described, but the present invention is not limited to this, as long as the 2 nd retardation layer 32 is provided between the high refractive index layer 45 and the linear polarization layer 11. For example, the 2 nd retardation layer 32 may be provided between the 1 st retardation layer 31 and the linear polarization layer 11. In this case, the 2 nd retardation layer 32 preferably covers the entire linearly polarizing layer 11. The plan view shape of the 2 nd retardation layer 32 is preferably the same as the plan view shape of the 1 st retardation layer 31.

In the case where the display devices 3 and 4 and the optical stacks 53 and 54 have the 2 nd retardation layer 32 between the 1 st retardation layer 31 and the linear polarization layer 11, the display devices 3 and 4 and the optical stacks 53 and 54 may have the 6 th adhesive layer 26 between the 2 nd retardation layer 32 and the 1 st retardation layer 31. The 2 nd adhesive layer 22 may be provided between the 2 nd retardation layer 32 and the linear polarizing layer 11, and for example, the 2 nd adhesive layer 22 may be in direct contact with the 2 nd retardation layer 32 and the 1 st protective film 12.

Hereinafter, the display device described above, layers constituting the display device, and the like will be described in more detail.

(display device)

The display device described above can be used as a liquid crystal display device or an organic EL (electro luminescence) display device. The display device may be a portable terminal such as a smart phone or a tablet computer. The display device may be a flexible display that is capable of bending.

The outline of the display area of the display device in plan view is not particularly limited, and may be rectangular, square, polygonal other than rectangular and square, or rounded corners in which corners are rounded (having the shape of R). The rectangular, square, polygonal, or rounded display area may have a through hole for disposing a camera or the like.

(display element)

The display element may be a liquid crystal display element or an organic EL display element. The liquid crystal display element may include, for example, a liquid crystal cell and a backlight, in which a liquid crystal layer is sandwiched between 2 cell substrates. The organic EL display element may have, for example, a light-emitting layer, an electrode, and the like.

The light emitted from the display element is preferably light having a wavelength of 320nm to 4000nm, more preferably light having a wavelength of 380nm to 780nm (visible light range), and may be light having a wavelength of 380nm to 720 nm.

(light-receiving sensor)

The light receiving sensor detects the incident light. The light receiving sensor may be an illuminance sensor that detects illuminance around the display device, a proximity sensor that detects proximity of an object, or a sensor that constitutes a camera or the like. The light receiving sensor is preferably capable of detecting light having a wavelength of 320nm to 4000nm, more preferably 380nm to 780nm (visible light range), and/or 780nm to 4000nm (infrared range).

(touch sensor Panel)

The display device and the optical stack may include a touch sensor panel. The touch sensor panel can detect a position touched by a user with a finger or the like. Examples of the touch sensor panel include touch sensor panels of a resistive film type, a capacitive coupling type, a photosensor type, an ultrasonic type, an electromagnetic induction coupling type, a surface elastic wave type, and the like, and among them, touch sensor panels of a resistive film type and a capacitive coupling type can be suitably used.

In the display device and the optical laminate, the touch sensor panel may be provided on the visible side of the linear polarization layer (the 1 st retardation layer side of the linear polarization layer), or may be provided on the opposite side of the linear polarization layer from the visible side. In the case where the touch sensor panel is provided on the visible side of the linear polarization layer, the touch sensor panel may constitute a high refractive index layer described later. In the case where the touch sensor panel is provided on the side of the linear polarization layer opposite to the visible side, the touch sensor panel is preferably provided between the linear polarization layer and the display unit.

(high refractive index layer)

The high refractive index layer is not particularly limited as long as it has a refractive index within the range (1.60 or more) defined in the present embodiment. If the high refractive index layer is a layer having the refractive index described above, the high refractive index layer may be a front panel of a display device or a touch sensor panel. The high refractive index layer may have a single-layer structure or a multilayer structure. In the case where the high refractive index layer has a multilayer structure, if the high refractive index layer has the refractive index described above, the high refractive index layer may include a layer having a refractive index less than 1.60.

The front panel may constitute the forefront of the display device. The front panel may be a plate-like body capable of transmitting light, and may be, for example, a resin plate, a resin film, a glass plate, or a glass film. The front panel may have a single-layer structure or a multilayer structure. The refractive index of the front panel may be 1.45 or more and 1.9 or less.

The polymer constituting the resin sheet or the resin film is not particularly limited as long as it is a resin capable of transmitting light. Examples of such a polymer include triacetylcellulose, acetylbutyrate, ethylene-vinyl acetate copolymer, propionylcellulose, butyrylcellulose, levulinyl cellulose, polyester, polystyrene, polyamide, polyetherimide, poly (meth) acrylic acid, polyimide, polyethersulfone, polysulfone, polyethylene, polypropylene, polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetal, polyetherketone, polyetheretherketone, polyethersulfone, polymethyl (meth) acrylate, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, and polyamideimide. These polymers may be used singly or in combination of 2 or more. In the present specification, (meth) acrylic means acrylic and/or methacrylic, and (meth) acrylate means acrylate and/or methacrylate.

In the case where the front panel is a resin film, the front panel may have a hard coat layer on at least one surface of the resin film. The hard coat layer is, for example, a cured layer of an ultraviolet curable resin. Examples of the ultraviolet curable resin include (meth) acrylic resins such as monofunctional (meth) acrylic resins, polyfunctional (meth) acrylic resins, and polyfunctional (meth) acrylic resins having a dendritic polymer structure; a silicone resin; a polyester resin; a urethane resin; an amide resin; epoxy resins, and the like. To increase strength, the hard coating layer may contain additives. The additive is not particularly limited, and examples thereof include inorganic fine particles, organic fine particles, or a mixture thereof. In the case where the resin film has hard coat layers on both sides, the composition and thickness of each hard coat layer may be the same or different from each other.

When the front panel is a glass plate or a glass film, a display tempered glass is preferably used.

As a touch sensor panel constituting the high refractive index layer, the above-described touch sensor panel can be exemplified. When the touch sensor panel constitutes the high refractive index layer, the refractive index of the touch sensor panel is 1.60 or more, preferably 1.70 or more, more preferably 1.90 or more, and generally 2.70 or less, preferably 2.60 or less, more preferably 2.40 or less.

(1 st phase difference layer, 2 nd phase difference layer, 3 rd phase difference layer, 4 th phase difference layer)

The 1 st retardation layer, the 2 nd retardation layer, the 3 rd retardation layer, and the 4 th retardation layer (hereinafter, these may be collectively referred to as "retardation layers") may be stretched films or may be layers containing cured layers of polymerizable liquid crystal compounds.

When the retardation layer is a stretched film, a stretched film conventionally known can be used, and a stretched film to which a retardation is imparted by uniaxially stretching or biaxially stretching a resin film can be used. As the resin film, a cellulose film such as triacetyl cellulose and diacetyl cellulose, a polyester film such as polyethylene terephthalate, polyethylene isophthalate and polybutylene terephthalate, an acrylic resin film such as polymethyl (meth) acrylate and polyethyl (meth) acrylate, a polycarbonate film, a polyethersulfone film, a polysulfone film, a polyimide film, a polyolefin film, a polynorbornene film, and the like can be used, but are not limited thereto.

When the retardation layer is a stretched film, the thickness of the retardation layer is usually 5 μm or more and 200 μm or less, preferably 10 μm or more and 80 μm or less, and more preferably 40 μm or less.

When the retardation layer includes the cured layer, a conventionally known polymerizable liquid crystal compound can be used as the polymerizable liquid crystal compound. The polymerizable liquid crystal compound has at least 1 polymerizable group and has liquid crystallinity.

The type of the polymerizable liquid crystal compound is not particularly limited, and a rod-like liquid crystal compound, a discotic liquid crystal compound, and a mixture thereof may be used. The cured product layer formed by polymerizing the polymerizable liquid crystal compound is cured in a state where the polymerizable liquid crystal compound is oriented in a proper direction, thereby exhibiting a phase difference. When the rod-shaped polymerizable liquid crystal compound is oriented horizontally or vertically with respect to the planar direction of the display device, the optical axis of the polymerizable liquid crystal compound coincides with the long axis direction of the polymerizable liquid crystal compound. When the disk-shaped polymerizable liquid crystal compound is aligned, the optical axis of the polymerizable liquid crystal compound is present in a direction perpendicular to the disk surface of the polymerizable liquid crystal compound. As the rod-like polymerizable liquid crystal compound, for example, a polymerizable liquid crystal compound described in JP-A-11-513019 (claim 1 and the like) can be suitably used. As the disk-shaped polymerizable liquid crystal compound, those described in JP-A2007-108732 (paragraphs [0020] to [0067] and the like) and JP-A2010-244038 (paragraphs [0013] to [0108] and the like) can be suitably used.

The polymerizable group of the polymerizable liquid crystal compound is a group involved in polymerization reaction, and is preferably a photopolymerizable group. The photopolymerizable group means a group capable of participating in polymerization reaction by utilizing a reactive radical, an acid, or the like generated from a photopolymerization initiator. Examples of the polymerizable group include vinyl, vinyloxy, 1-chlorovinyl, isopropenyl, 4-vinylphenyl, (meth) acryloyloxy, epoxyethyl, oxetanyl, styryl, and allyl. Among them, (meth) acryloyloxy, ethyleneoxy, ethyleneoxide and oxetanyl groups are preferred, and acryloyloxy is more preferred. The liquid crystallinity of the polymerizable liquid crystal compound may be either thermotropic liquid crystal or lyotropic liquid crystal, or nematic liquid crystal or smectic liquid crystal when the thermotropic liquid crystal is classified into ordered ones. In the case where 2 or more polymerizable liquid crystal compounds are used in combination for forming a cured layer of the polymerizable liquid crystal compound, at least 1 type of polymerizable compound having 2 or more polymerizable groups in the molecule is preferable. In the present specification, (meth) acryl means acryl and/or methacryl.

In the case where the retardation layer includes the cured layer, the retardation layer may include an alignment layer. The alignment layer has an alignment regulating force for aligning the polymerizable liquid crystal compound in a desired direction. The alignment layer may be a vertical alignment layer that vertically aligns the molecular axis of the polymerizable liquid crystal compound with respect to the planar direction of the display device, a horizontal alignment layer that horizontally aligns the molecular axis of the polymerizable liquid crystal compound with respect to the planar direction of the display device, or an oblique alignment layer that obliquely aligns the molecular axis of the polymerizable liquid crystal compound with respect to the planar direction of the display device. In the case where the retardation layer includes 2 or more alignment layers, the alignment layers may be the same or different from each other.

The alignment layer is preferably one having solvent resistance that is not dissolved by application or the like of a composition for forming a liquid crystal layer containing a polymerizable liquid crystal compound and heat resistance for heat treatment for removing the solvent and aligning the polymerizable liquid crystal compound. Examples of the alignment layer include an alignment polymer layer formed of an alignment polymer, a photo-alignment polymer layer formed of a photo-alignment polymer, and a groove alignment layer having a concave-convex pattern and a plurality of grooves (grooves) on the layer surface.

The cured product layer may be formed by applying a composition for forming a retardation layer, which contains a polymerizable liquid crystal compound and a solvent, and various additives, if necessary, to an alignment layer to form a coating film, and curing (hardening) the coating film to form a cured product layer of the polymerizable liquid crystal compound. Alternatively, the composition may be applied to a base layer to form a coating film, and the coating film may be stretched together with the base layer to form a cured product layer. The composition may contain a polymerization initiator, a reactive additive, a leveling agent, a polymerization inhibitor, and the like in addition to the polymerizable liquid crystal compound and the solvent. The polymerizable liquid crystal compound, solvent, polymerization initiator, reactive additive, leveling agent, polymerization inhibitor, etc. may be appropriately used.

As the base layer, a film formed of a resin material may be used, and for example, a film using a resin material described as a thermoplastic resin for forming a 1 st protective film described later may be used. The thickness of the base material layer is not particularly limited, but is generally preferably 1 to 300 μm or less, more preferably 20 to 200 μm, and still more preferably 30 to 120 μm in view of workability such as strength and workability. The base material layer may be incorporated into the display device together with the cured product layer of the polymerizable liquid crystal compound, or may be incorporated into the display device after the base material layer is peeled off, only the cured product layer of the polymerizable liquid crystal compound, or the cured product layer and the alignment layer. In the case where the base material layer is incorporated into the display device together with the cured product layer of the polymerizable liquid crystal compound, the thickness of the base material layer may be less than 30 μm, for example, 25 μm or less.

When the retardation layer contains the cured layer, the thickness of the retardation layer is preferably 0.1 μm or more, more preferably 0.2 μm or more, and further preferably 3 μm or less, more preferably 2 μm or less.

(Linear polarization layer)

The linear polarization layer transmits linearly polarized light having a vibration plane orthogonal to an absorption axis when unpolarized light is incident. The linear polarizing layer may be a polyvinyl alcohol resin film (hereinafter, sometimes referred to as "PVA-based film") to which iodine is adsorbed and which is oriented, or may be a film including a liquid-crystalline polarizing layer formed by applying a composition containing a compound having absorption anisotropy and liquid-crystalline properties to a base film. The compound having absorption anisotropy and liquid crystallinity may be a mixture of a dye having absorption anisotropy and a compound having liquid crystallinity, or may be a dye having absorption anisotropy and liquid crystallinity.

The linear polarization layer is preferably a PVA-based film having iodine adsorbed and oriented thereto. Examples of the linear polarization layer of the PVA film include a PVA film obtained by subjecting a PVA film such as a polyvinyl alcohol film, a partially formalized polyvinyl alcohol film, or an ethylene-vinyl acetate copolymer partially saponified film to a dyeing treatment with iodine and a stretching treatment. If necessary, the PVA-based film having iodine adsorbed and oriented by the dyeing treatment may be treated with an aqueous boric acid solution, and then subjected to a washing step of washing away the aqueous boric acid solution. The steps may be performed by a known method.

Polyvinyl alcohol-based resins (hereinafter sometimes referred to as "PVA-based resins") can be produced by saponifying polyvinyl acetate-based resins. The polyvinyl acetate resin may be polyvinyl acetate which is a homopolymer of vinyl acetate, or may be a copolymer of vinyl acetate and another monomer copolymerizable with vinyl acetate. Examples of the other monomer copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group.

The saponification degree of the PVA-based resin is usually about 85 to 100 mol%, preferably 98 mol% or more. The PVA-based resin may be modified, and for example, polyvinyl formal, polyvinyl acetal, or the like modified with an aldehyde may be used. The average polymerization degree of the PVA-based resin is usually about 1000 to 10000, preferably about 1500 to 5000. The saponification degree and the average polymerization degree of the PVA based resin can be determined in accordance with JIS K6726 (1994). If the average polymerization degree is less than 1000, it is difficult to obtain preferable polarization performance, and if it exceeds 10000, film processability may be poor.

The method for producing the linear polarization layer as the PVA-based film may include a step of preparing a base film, applying a solution of a resin such as a PVA-based resin to the base film, and drying the solution to remove the solvent, thereby forming a resin layer on the base film. The primer layer may be formed in advance on the resin layer-forming surface of the base film. As the base film, a film using a resin material described as a thermoplastic resin for forming a 1 st protective film described later can be used. Examples of the material of the primer layer include a resin obtained by crosslinking a hydrophilic resin used for the linearly polarizing layer.

Then, the solvent amount such as moisture of the resin layer is adjusted as needed, and thereafter, the base film and the resin layer are uniaxially stretched, and then the resin layer is dyed with iodine to adsorb iodine to the resin layer and orient the same. Then, if necessary, a cleaning step is performed in which the resin layer having iodine adsorbed and oriented is treated with an aqueous boric acid solution, and then the aqueous boric acid solution is rinsed off. Thus, a resin layer having iodine adsorbed and oriented thereto, that is, a PVA-based film serving as a linearly polarizing layer can be produced. The steps may be performed by a known method.

The amount of boric acid in the aqueous solution containing boric acid to which the PVA-based film or resin layer having iodine adsorbed and oriented is usually about 2 to 15 parts by mass, preferably 5 to 12 parts by mass, per 100 parts by mass of water. The aqueous solution containing boric acid preferably contains potassium iodide. The amount of potassium iodide in the aqueous solution containing boric acid is usually about 0.1 to 15 parts by mass, preferably about 5 to 12 parts by mass, per 100 parts by mass of water. The immersion time in the aqueous solution containing boric acid is usually about 60 to 1200 seconds, preferably about 150 to 600 seconds, and more preferably about 200 to 400 seconds. The temperature of the aqueous solution containing boric acid is usually 50℃or higher, preferably 50 to 85℃and more preferably 60 to 80 ℃.

The uniaxial stretching of the PVA-based film, the base film, and the resin layer may be performed before dyeing, during boric acid treatment after dyeing, or in a plurality of stages thereof. The PVA-based film, the base film, and the resin layer may be uniaxially stretched in the MD direction (film conveyance direction), and in this case, stretching may be performed uniaxially between rolls having different peripheral speeds, or stretching may be performed uniaxially using a hot roll. In addition, the PVA-based film, the base film, and the resin layer may be uniaxially stretched in the TD direction (the direction perpendicular to the film conveying direction), and in this case, a so-called tenter method may be used. The stretching may be a dry stretching performed in the atmosphere or a wet stretching performed in a state where the PVA-based film or the resin layer is swollen with a solvent. In order to exhibit the performance of the linearly polarizing layer, the stretching ratio is 4 times or more, preferably 5 times or more, and particularly preferably 5.5 times or more. The upper limit of the stretching ratio is not particularly limited, but is preferably 8 times or less from the viewpoint of suppressing breakage or the like.

The linear polarization layer manufactured by the manufacturing method using the base film can be obtained by peeling the base film after stacking the 1 st or 2 nd protective film. According to this method, further thinning of the linear polarization layer can be achieved.

The thickness of the linear polarization layer as the PVA film is preferably 1 μm or more, may be 2 μm or more, may be 5 μm or more, and is preferably 30 μm or less, more preferably 15 μm or less, may be 10 μm or less, and may be 8 μm or less.

Examples of the film containing a polarizing layer having liquid crystallinity include a linear polarizing layer obtained by applying a composition containing a dye having liquid crystallinity and absorption anisotropy or a composition containing a dye having absorption anisotropy and a polymerizable liquid crystal to a substrate film. Examples of the base film include films using a resin material described as a thermoplastic resin for forming the 1 st protective film described later. Examples of the film containing a polarizing layer having liquid crystallinity include polarizing layers described in japanese patent application laid-open publication No. 2013-33249.

The total thickness of the base film and the linearly polarizing layer formed as described above is preferably small, but if too small, the strength tends to be low, and thus is usually 20 μm or less, preferably 5 μm or less, and more preferably 0.5 to 3 μm.

The linearly polarizing layer (PVA-based film, film including a liquid crystalline polarizing layer) obtained as described above may be incorporated into a display device in a state of being a linearly polarizing plate in which a 1 st protective film and/or a 2 nd protective film described later are laminated on one or both surfaces thereof via an adhesive. In the film including the polarizing layer having liquid crystallinity, the above-described base film may be a 1 st protective film or a 2 nd protective film.

(1 st protective film, 2 nd protective film)

As the 1 st protective film and the 2 nd protective film, for example, films formed of thermoplastic resins excellent in transparency, mechanical strength, thermal stability, water resistance, isotropy, stretchability, and the like are used. Specific examples of the thermoplastic resin include cellulose resins such as triacetyl cellulose; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polyether sulfone resin; polysulfone resin; a polycarbonate resin; polyamide resins such as nylon and aromatic polyamide; polyimide resin; polyolefin resins such as polyethylene, polypropylene and ethylene-propylene copolymers; a cyclic polyolefin resin having a ring system and a norbornene structure (also referred to as a norbornene-based resin); (meth) acrylic resins; a polyarylate resin; a polystyrene resin; polyvinyl alcohol resins and mixtures thereof. The resin compositions of the 1 st protective film and the 2 nd protective film may be the same or different.

The 1 st protective film may be a film having an antireflection property, an antiglare property, a hard coat property, or the like (hereinafter, a protective film having such a property may be referred to as a "functional protective film"). In the case where the 1 st protective film is not a functional protective film, a surface functional layer such as an antireflection layer, an antiglare layer, or a hard coat layer may be provided on one surface of the linear polarizing plate. The surface functional layer is preferably provided in direct contact with the 1 st protective film. The surface functional layer is preferably provided on the opposite side of the 1 st protective film from the linear polarization layer side.

The 1 st protective film and the 2 nd protective film are each independently preferably 3 μm or more, more preferably 5 μm or more, and further preferably 50 μm or less, more preferably 30 μm or less.

(1 st bonding layer, 2 nd bonding layer, 3 rd bonding layer, 4 th bonding layer, 5 th bonding layer, 6 th bonding layer)

The 1 st bonding layer, the 2 nd bonding layer, the 3 rd bonding layer, the 4 th bonding layer, the 5 th bonding layer, the 6 th bonding layer, and the bonding layers (hereinafter, these may be collectively referred to as "bonding layers") are each independently an adhesive layer or an adhesive layer.

When the adhesive layer is an adhesive layer, the adhesive layer is formed using an adhesive composition. The pressure-sensitive adhesive composition or the reaction product of the pressure-sensitive adhesive composition is a substance exhibiting adhesiveness by adhering itself to an adherend such as a metal layer, and is called a so-called pressure-sensitive adhesive. The adhesive layer formed using the active energy ray-curable adhesive composition described later can be adjusted in crosslinking degree and adhesion by irradiation with active energy rays.

The pressure-sensitive adhesive composition may be any pressure-sensitive adhesive having excellent optical transparency known in the related art, and may be, for example, a pressure-sensitive adhesive composition containing a base polymer such as an acrylic polymer, a urethane polymer, a silicone polymer, or a polyvinyl ether. The adhesive composition may be an active energy ray-curable adhesive composition, a thermosetting adhesive composition, or the like. Among them, an adhesive composition containing an acrylic resin as a base polymer, which is excellent in transparency, adhesion, removability (reworkability), weather resistance, heat resistance, and the like, is suitable. The adhesive layer is preferably composed of a reaction product of an adhesive composition containing a (meth) acrylic resin, a crosslinking agent, and a silane compound, and may contain other components.

The adhesive layer may be formed using an active energy ray-curable adhesive. In the active energy ray-curable pressure-sensitive adhesive, a pressure-sensitive adhesive layer can be formed by adding an ultraviolet-curable compound such as a polyfunctional acrylate to the pressure-sensitive adhesive composition, and then curing the pressure-sensitive adhesive by irradiation with ultraviolet rays. The active energy ray-curable adhesive has a property of being cured after being irradiated with energy rays such as ultraviolet rays and electron beams. The active energy ray-curable pressure-sensitive adhesive has adhesion to an adherend even before irradiation with energy rays, and has a property of being cured by irradiation with energy rays to adjust adhesion force.

The thickness of the pressure-sensitive adhesive layer is not particularly limited, and may be preferably 5 μm or more, or may be 10 μm or more, or may be 15 μm or more, or may be 20 μm or more, or may be 25 μm or more, or may be 300 μm or less, or may be 250 μm or less, or may be 100 μm or less, or may be 50 μm or less.

When the adhesive layer is an adhesive layer, the adhesive layer can be formed by curing a curable component in the adhesive composition. The adhesive composition used for forming the adhesive layer is an adhesive other than a pressure-sensitive adhesive (adhesive), and examples thereof include an aqueous adhesive and an active energy ray-curable adhesive.

Examples of the aqueous adhesive include an adhesive obtained by dissolving or dispersing a polyvinyl alcohol resin in water. The drying method when the aqueous adhesive is used is not particularly limited, and for example, a method of drying using a hot air dryer or an infrared dryer may be used.

Examples of the active energy ray-curable adhesive include solvent-free active energy ray-curable adhesives containing curable compounds that cure by irradiation with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays. The use of the solvent-free active energy ray-curable adhesive can improve interlayer adhesion.

The active energy ray-curable adhesive preferably contains one or both of a cationically polymerizable curable compound and a radically polymerizable curable compound, in order to exhibit good adhesion. The active energy ray-curable adhesive may further contain a cationic polymerization initiator such as a photo-cationic polymerization initiator or a radical polymerization initiator for initiating the curing reaction of the curable compound.

Examples of the cationically polymerizable curable compound include an alicyclic epoxy compound having an epoxy group bonded to an alicyclic ring, a polyfunctional aliphatic epoxy compound having 2 or more epoxy groups and having no aromatic ring, a monofunctional epoxy compound having 1 epoxy group (excluding epoxy groups contained in the alicyclic epoxy compound), and a polyfunctional aromatic epoxy compound having 2 or more epoxy groups and having an aromatic ring; oxetane compounds having 1 or more than 2 oxetane rings in the molecule; a combination thereof.

Examples of the radically polymerizable curable compound include (meth) acrylic compounds (compounds having 1 or 2 or more (meth) acryloyloxy groups in the molecule), other vinyl compounds having radically polymerizable double bonds, and combinations thereof.

The active energy ray-curable adhesive may contain a sensitizer such as a photosensitive aid as needed. By using the sensitizer, the reactivity is improved, and the mechanical strength and the adhesive strength of the adhesive layer can be further improved. As the sensitizer, a known sensitizer can be appropriately used. When the sensitizer is blended, the blending amount is preferably in the range of 0.1 to 20 parts by mass based on 100 parts by mass of the total amount of the active energy ray-curable adhesive.

The active energy ray-curable adhesive may contain additives such as ion scavenger, antioxidant, chain transfer agent, tackifier, thermoplastic resin, filler, flow regulator, plasticizer, defoamer, antistatic agent, leveling agent, solvent, and the like, as necessary.

When an active energy ray-curable adhesive is used, an adhesive layer can be formed by curing a coating layer of the adhesive by irradiation with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays. The active energy ray is preferably ultraviolet rays, and a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultra-high pressure mercury lamp, a chemical lamp, a black light lamp, a microwave excitation mercury lamp, a metal halide lamp, or the like can be used as the light source in this case.

The thickness of the adhesive layer is preferably 0.1 μm or more, but may be 0.5 μm or more, and preferably 10 μm or less, but may be 5 μm or less.

Examples

Hereinafter, the present invention will be described in further detail with reference to examples, but the present invention is not limited to these examples.

[ measurement of refractive index ]

The refractive index of the high refractive index layer was measured at 25℃using a multi-wavelength Abbe refractometer (manufactured by ATAGO Co., ltd. "DR-M4") with a measurement wavelength of 589 nm.

[ measurement of visibility correction monomer transmittance Ty ]

For the linear polarization layer, the MD transmittance and TD transmittance in the wavelength range of 380 to 780nm were measured using a spectrophotometer with an integrating sphere ("V7100" manufactured by japan spectroscope, ltd.) and the monomer transmittance at each wavelength was calculated based on the following formula:

monomer transmittance (%) = (md+td)/2

The "MD transmittance" is a transmittance obtained when the direction of polarized light emitted from the granthomson prism is parallel to the transmission axis of the linear polarization layer, and is expressed by the expression "MD" in the above expression. The term "TD transmittance" refers to a transmittance obtained when the direction of polarized light emitted from the granthomson prism is perpendicular to the transmission axis of the linear polarization layer, and is expressed as "TD" in the above formula. For the transmittance of the obtained monomer, JIS Z8701 was used: 1999' color representation method-XYZ color system and X ₁₀ Y ₁₀ Z ₁₀ The visibility correction was performed on the 2-degree field of view (C light source) of the color system ", and the visibility correction monomer transmittance was obtained.

[ measurement of in-plane phase Difference value ]

The in-plane retardation values of the 1 st retardation layer and the 1 st protective film were measured by a retardation measuring apparatus (KOBRA-WPR, manufactured by prince measuring instruments Co., ltd.).

[ measurement of phase Difference in thickness direction ]

The thickness-direction retardation value of the 2 nd retardation layer was measured by a retardation measuring apparatus (KOBA-WPR, manufactured by prince measuring instruments Co., ltd.). In the measurement, the incident angle of light to the 2 nd retardation layer was changed, and the front retardation value of the 2 nd retardation layer and the retardation value when inclined by 40 ° about the fast axis were measured. The average refractive index at each wavelength was measured using an ellipsometer M-220 manufactured by Japan light splitting Co. The thickness of the 2 nd retardation layer was measured by using a Optical NanoGauge film thickness meter C12562-01 manufactured by Hamamatsu Photonics Co. Based on the values of the front phase difference value, the phase difference value when inclined by 40 ° about the fast axis, the average refractive index, and the thickness of the 2 nd phase difference layer measured in the above, the three-dimensional refractive index was calculated with reference to prince measurement machine technical data (https:// oji-keisoku.co.jp/cms/uploads/kbr _shiryo04. Pdf). From the obtained three-dimensional refractive index, the thickness direction retardation value Rth of the 2 nd retardation layer was calculated in accordance with the above formula (i).

[ measurement of stimulus value Y ]

For the measurement of the stimulus value Y, a spectrocolorimeter [ CM2600d manufactured by Konica Minolta Co., ltd ] was used. The stimulus value Y of the reflected light was measured by light incident on the spectrocolorimeter from the moth-eye film side of the laminate. Since the reflectance of the moth-eye film is very small, the influence of interfacial reflection of light from the spectrocolorimeter between air and the moth-eye film can be ignored. In the measurement, it was confirmed that an object having no light reflectivity in the light traveling direction of 1m or less was present in the light receiving/emitting section of the spectrocolorimeter, and the measurement was performed in a sufficiently dark environment to eliminate the influence of external light. As a result of measurement by a spectrocolorimeter in the state where no sample (laminate) was measured in this measurement environment, it was confirmed that the stimulus value Y was 0.1% or less. Therefore, when the stimulus value Y of the laminate is measured in the above-described measurement environment, a part of the light detected by the spectrocolorimeter is absorbed by the polarizer, and only the light reflected by the high refractive index layer.

[ example 1 ]

(production of polarizing plate (1))

A polyvinyl alcohol resin film having a thickness of 20 μm (average polymerization degree: about 2400, saponification degree: 99.9 mol% or more) was uniaxially stretched in the machine direction at a stretch ratio of about 4.5 times by dry stretching. The stretched state was kept unchanged, and immersed in pure water at 30℃for 60 seconds. Then, the tension was kept constant, and the solution was immersed in an aqueous solution of iodine/potassium iodide at a mass ratio of iodine/potassium iodide/water of 0.05/5/100 and a temperature of 28℃for 60 seconds. Then, the tension was maintained, and the solution was immersed in an aqueous potassium iodide/boric acid solution having a mass ratio of potassium iodide/boric acid/water of 15/5.5/100 and a temperature of 64℃for 170 seconds. Then, the film was dried in the air at 80℃for 70 seconds while maintaining the state of tension, and the polyvinyl alcohol resin film was aligned by adsorbing iodine, whereby a polarizing plate (1) (linear polarizing layer) having a thickness of 8 μm was produced. The visibility correction monomer transmittance Ty of the polarizing plate (1) was 42.2.+ -. 0.5%.

(preparation of the 1 st phase-difference layer (1))

A cyclic polyolefin resin film having a thickness of 25 μm and a hard coat layer was prepared as the 1 st retardation layer (1). The in-plane phase difference value at the wavelength of 550nm of the 1 st phase difference layer (1) was 100nm.

(preparation of aqueous adhesive)

To 100 parts by mass of water, 3 parts by mass of carboxyl group-modified polyvinyl alcohol (manufactured by Kuraray corporation, "KL-318") was dissolved to obtain an aqueous polyvinyl alcohol solution, and to the aqueous polyvinyl alcohol solution (100 parts by mass of water), water-soluble polyamide epoxy Resin (manufactured by the industrial chemical industry of field-okang, "sumitez Resin 650 (30)") and 1.5 parts by mass of solid content (solid content: 0.45 parts by mass) were added to obtain an aqueous adhesive.

(production of Linear polarization plate (1))

A cyclic polyolefin resin film having a thickness of 13 μm was prepared as the 1 st protective film. A triacetyl cellulose resin film (KC 4UY, manufactured by Konica Minolta Co., ltd., thickness 40 μm) having no saponification treatment was prepared as a 2 nd protective film.

The 1 st protective film (cyclic polyolefin resin film) prepared above was laminated on one surface of the polarizing plate (1) obtained above via the aqueous adhesive obtained above, the 2 nd protective film (triacetyl cellulose resin film) prepared above was laminated on the other surface of the polarizing plate (1) via pure water, passed between a pair of laminating rollers, and then heat-dried at 85 ℃ for 3 minutes, whereby the aqueous adhesive was cured to form an adhesive layer as a 3 rd lamination layer, and a linear polarizing plate (1) having a layer structure of 1 st protective film/3 rd lamination layer/polarizing plate (1)/2 nd protective film was produced. The in-plane phase difference value at 550nm of the wavelength of the 1 st protective film was 0nm.

(production of high refractive index layer)

On one surface of an alkali-free glass plate (Eagle XG, manufactured by Corning Co., ltd., refractive index 1.50), a film of ITO (Indium Tin Oxide), which is a mixture of indium oxide and tin oxide, was formed by vacuum vapor deposition to form an ITO layer having a thickness of 100 μm, thereby obtaining a high refractive index layer as a laminated structure of the alkali-free glass plate and the ITO layer. The refractive index of the high refractive index layer was measured from the ITO layer side, and as a result, it was 2.00.

(production of laminate (1))

Then, the 2 nd protective film was peeled off from the linear polarizing plate (1), and a moth-eye film (g.moth, manufactured by geomotec corporation) was laminated on the exposed polarizing plate (1) side via a 4 th lamination layer (acrylic adhesive layer having a thickness of 25 μm), and a laminated structure (refractive index 2.00) of a 2 nd lamination layer (acrylic adhesive layer having a thickness of 5 μm), a 1 st retardation layer (1), a 1 st lamination layer (acrylic adhesive layer having a thickness of 25 μm), an alkali-free glass plate (Eagle XG, refractive index 1.50) having a refractive index of 1.50, and a high refractive index layer (ITO layer), and a black acrylic plate (vac) were laminated in this order on the 1 st protective film side of the linear polarizing plate (1), to produce a laminated body (1). The laminate (1) is laminated such that the high refractive index layer is on the black acrylic plate side. The space between the high refractive index layer and the black acrylic plate is filled with ethanol added dropwise before lamination, and the air layer is eliminated. The 1 st retardation layer (1) is laminated so that the hard coat layer side is the high refractive index layer side. In the laminated body (1), the angle between the slow axis of the 1 st phase difference layer (1) and the absorption axis of the polarizing plate (1) of the linear polarizing plate (1) is 45 degrees. The layer structure of the obtained laminate (1) was black acrylic sheet/ethanol/high refractive index layer/1 st lamination layer/1 st retardation layer (1)/2 nd lamination layer/1 st protective film/3 rd lamination layer/polarizer (1)/4 th lamination layer/moth-eye film. The results obtained by measuring the stimulus value Y of the laminate (1) are shown in table 1. The moth-eye film is designed so as to evaluate the laminate (1) while ignoring the influence of the interfacial reflection between the 4 th lamination layer and the air layer, and in an actual display device, a display unit is arranged on the side of the 4 th lamination layer opposite to the polarizing plate (1).

[ example 2 ]

(preparation of the 1 st phase-difference layer (2))

A50 μm thick cyclic polyolefin resin film was prepared as the 1 st retardation layer (2). The in-plane phase difference value at the wavelength of 550nm of the 1 st phase difference layer (2) was 141nm.

(production of laminate (2))

A laminate (2) was obtained in the same manner as in example 1, except that the 1 st retardation layer (2) was used instead of the 1 st retardation layer (1). The layer structure of the obtained laminate (2) was black acrylic plate/ethanol/high refractive index layer/1 st lamination layer/1 st retardation layer (2)/2 nd lamination layer/1 st protective film/3 rd lamination layer/polarizer (1)/4 th lamination layer/moth-eye film. The results obtained by measuring the stimulus value Y of the laminate (2) are shown in table 1.

[ example 3 ]

(preparation of composition for Forming horizontal alignment film)

5 parts by mass of a photo-alignment polymer having the following structure (described in Japanese unexamined patent publication No. 2013-33249) and 95 parts by mass of cyclopentanone (solvent) were mixed and stirred at 80℃for 1 hour, thereby obtaining a composition for forming a horizontal alignment film.

Photo-alignment polymer (5 parts by mass):

[ chemical formula 1]

Solvent (95 parts by mass): cyclopentanone (CNG)

(preparation of polymerizable liquid Crystal composition (A1) for Forming phase-Shift layer (3))

The polymerizable liquid crystal compound (X1) and the polymerizable liquid crystal compound (X2) were mixed in a mass ratio of 90:10 to obtain a mixture. To 100 parts of the resultant mixture, 0.1 part of a leveling agent "BYK-361N" (manufactured by BM Chemie Co., ltd.) and 6 parts of 2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) -1-butanone (BASF JAPAN Co., ltd. "Irgacure (registered trademark) 369 (Irg 369)") as photopolymerization initiators were added. Then, N-methyl-2-pyrrolidone (NMP) was added so that the solid content concentration was 13%. The mixture was stirred at 80℃for 1 hour, thereby obtaining a polymerizable liquid crystal composition (A1) for forming A1 st retardation layer (3).

Polymerizable liquid crystal compound (X1):

[ chemical formula 2]

Polymerizable liquid crystal compound (X2):

[ chemical formula 3]

(production of the 1 st phase-difference layer (3))

After corona treatment was performed on a COP (cyclic olefin resin) film (ZF-14-50) manufactured by ZEON Co., ltd., the above-obtained composition for forming a horizontal alignment film was applied by a bar coater, dried at 80℃for 1 minute, and then subjected to a cumulative light amount at a wavelength of 313nm using a polarized UV irradiation apparatus (SPOTCURE SP-9; manufactured by USHIO Motor Co., ltd.): 100mJ/cm ² Polarized UV exposure was performed under the conditions of (2) to obtain a horizontally oriented film. The film thickness of the resulting horizontally oriented film was measured with an ellipsometer and found to be 200nm.

Next, the polymerizable liquid crystal composition (A1) obtained above was applied onto the horizontal alignment film BY using a bar coater, heated at 120℃for 60 seconds, and then irradiated with ultraviolet light (cumulative light amount at 365nm wavelength under nitrogen atmosphere: 500 mJ/cm) from the surface coated with the polymerizable liquid crystal composition (A1) BY using a high-pressure mercury lamp (manufactured BY UNICURE VB-15201BY-A, USHIO Motor Co., ltd.) ² ) Thus, a horizontally aligned liquid crystal layer (cured layer of polymerizable liquid crystal compound) was formed, and a laminate structure (A1) having a layer structure of COP film/horizontally aligned liquid crystal layer was obtained. After confirming that there was no retardation in the COP film, the in-plane phase difference values Re (450) and Re (550) at the wavelengths 450nm and 550nm of the laminated structure (A1) were measured as in-plane phase difference values Re (450) and Re (550) of the 1 st retardation layer (3), and Re (550) was 139nm. Since Re (450)/Re (550) was calculated and found to be 0.87, it was confirmed that the laminate exhibited reverse wavelength dispersibility.

The COP film of the laminated structure (A1) is peeled off, and the 1 st retardation layer (3) is a horizontal alignment film/a horizontal alignment liquid crystal layer.

(production of laminate (3))

A laminate (3) was obtained in the same manner as in example 1, except that the 1 st retardation layer (3) was used instead of the 1 st retardation layer (1). The 1 st retardation layer (3) is laminated so that the horizontal alignment film side is the high refractive index layer side. The layer structure of the obtained laminate (3) was black acrylic plate/ethanol/high refractive index layer/1 st lamination layer/1 st retardation layer (3)/2 nd lamination layer/1 st protective film/3 rd lamination layer/polarizer (1)/4 th lamination layer/moth-eye film. The results obtained by measuring the stimulus value Y of the laminate (3) are shown in table 1.

[ example 4 ]

(preparation of composition for Forming vertical alignment film)

Silane coupling agent "KBE-9103" (manufactured by Xinyue chemical Co., ltd.) was dissolved in ethanol and water at a ratio of 9:1 (weight ratio) to obtain a composition for forming a vertical alignment film having a solid content of 1%.

(preparation of polymerizable liquid Crystal composition (A2) for Forming phase-Shift layer (1))

To 100 parts of paliocor LC242 (registered trademark of BASF corporation) as a polymerizable liquid crystal compound, 0.1 part of F-556 as a leveling agent and 3 parts of Irgacure 369 as a polymerization initiator were added. Cyclopentanone was added so that the solid content concentration became 13%, to obtain a polymerizable liquid crystal composition (A2).

(production of the 2 nd phase-difference layer (1))

After corona treatment was performed on a COP (cyclic olefin resin) film (ZF-14-50) manufactured by ZEON corporation, japan, a composition for forming a vertical alignment film was applied by a bar coater and dried at 120 ℃ for 1 minute, to obtain a vertical alignment film. The film thickness of the resulting homeotropic alignment film was measured with an ellipsometer and found to be 100nm.

Next, the polymerizable liquid crystal composition (A2) obtained above was applied onto the homeotropic alignment film using a coater, and after drying at 120℃for 1 minute, ultraviolet rays (cumulative light amount at 365nm wavelength under nitrogen atmosphere: 500 mJ/cm) were irradiated from the side coated with the polymerizable liquid crystal composition (A2) using a high-pressure mercury lamp (UNICURE VB-15201BY-A, USHIO Motor Co., ltd.) ² ) Thus, a vertical alignment liquid crystal layer (cured layer of polymerizable liquid crystal compound) was formed, and a laminate structure (A2) having a layer structure of COP film/vertical alignment liquid crystal layer was obtained. None of the COP films was confirmedAfter the retardation, the thickness-direction retardation value Rth (550) of the 2 nd retardation layer (1) was measured as the thickness-direction retardation value Rth (550) at the wavelength of 550nm of the laminated structure (A2), and as a result, rth (550) was-70 nm.

The COP film and the vertical alignment film of the laminated structure (A2) were peeled off, and the vertical alignment liquid crystal layer was set as the 2 nd retardation layer (1).

(production of laminate (4))

The phase difference laminate of the 2 nd phase difference layer (1)/the 6 th bonding layer/the 1 st phase difference layer (3) was produced by bonding the 2 nd phase difference layer (1) to the 1 st phase difference layer (3) on the side of the horizontally oriented liquid crystal layer produced by the same procedure as in example 3 using an ultraviolet-curable adhesive, and curing the ultraviolet-curable adhesive to form an adhesive layer (thickness 1 μm) as the 6 th bonding layer.

A laminate (4) was obtained in the same manner as in example 1, except that a retardation laminate was used instead of the 1 st retardation layer (1). The retardation laminate is laminated such that the 2 nd retardation layer (1) side is the high refractive index layer (1) side. The layer structure of the obtained laminate (4) was black acrylic plate/ethanol/high refractive index layer/1 st lamination layer/2 nd retardation layer (1)/6 th lamination layer/1 st retardation layer (3)/2 nd lamination layer/1 st protective film/3 rd lamination layer/polarizer (1)/4 th lamination layer/moth-eye film. The results obtained by measuring the stimulus value Y of the laminate (4) are shown in table 1.

TABLE 1

[ example 5 ]

(production of polarizing plate (2))

A polyvinyl alcohol resin film having a thickness of 20 μm (average polymerization degree: 2400, saponification degree: 99.9 mol% or more) was uniaxially stretched in the machine direction at a stretch ratio of about 4.5 times by dry stretching. The stretched state was kept unchanged, and immersed in pure water at 30℃for 60 seconds. Then, the tension was maintained, and the solution was immersed in an aqueous solution of iodine/potassium iodide at a mass ratio of iodine/potassium iodide/water of 0.02/5/100 and a temperature of 28℃for 60 seconds. Then, the tension was kept constant, and the solution was immersed in an aqueous potassium iodide/boric acid solution having a mass ratio of potassium iodide/boric acid/water of 15/5.5/100 and a temperature of 64℃for 45 seconds. Then, the film was dried in the air at 80℃for 75 seconds while maintaining the state of tension, and the polyvinyl alcohol resin film was aligned by adsorbing iodine, whereby a polarizing plate (2) (linear polarizing layer) having a thickness of 8 μm was produced. The visibility correction monomer transmittance Ty of the polarizing plate (2) was 46.0.+ -. 0.5%.

(production of laminate (5))

A laminate (5) was obtained in the same manner as in example 1, except that the polarizing plate (2) was used instead of the polarizing plate (1). The layer structure of the obtained laminate (5) was black acrylic plate/ethanol/high refractive index layer/1 st lamination layer/1 st retardation layer (1)/2 nd lamination layer/1 st protective film/3 rd lamination layer/polarizer (2)/4 th lamination layer/moth-eye film. The results of measuring the stimulus value Y of the laminate (5) are shown in table 2.

[ example 6 ]

A laminate (6) was obtained in the same manner as in example 2, except that the polarizing plate (2) was used instead of the polarizing plate (1). The layer structure of the obtained laminate (6) was black acrylic plate/ethanol/high refractive index layer/1 st lamination layer/1 st retardation layer (2)/2 nd lamination layer/1 st protective film/3 rd lamination layer/polarizer (2)/4 th lamination layer/moth-eye film. The results of measuring the stimulus value Y of the laminate (6) are shown in table 2.

Example 7

A laminate (7) was obtained in the same manner as in example 3, except that the polarizing plate (2) was used instead of the polarizing plate (1). The layer structure of the obtained laminate (7) was black acrylic plate/ethanol/high refractive index layer/1 st lamination layer/1 st retardation layer (3)/2 nd lamination layer/1 st protective film/3 rd lamination layer/polarizer (2)/4 th lamination layer/moth-eye film. The results of measuring the stimulus value Y of the laminate (7) are shown in table 2.

Example 8

A laminate (8) was obtained in the same manner as in example 4, except that the polarizing plate (2) was used instead of the polarizing plate (1). The layer structure of the obtained laminate (8) was black acrylic plate/ethanol/high refractive index layer/1 st lamination layer/2 nd retardation layer (1)/6 th lamination layer/1 st retardation layer (3)/2 nd lamination layer/1 st protective film/3 rd lamination layer/polarizer (2)/4 th lamination layer/moth-eye film. The results of measuring the stimulus value Y of the laminate (8) are shown in table 2.

Comparative example 1

A laminate (9) was obtained in the same manner as in example 5, except that the 1 st retardation layer (1) and the 2 nd lamination layer were not laminated, but the high refractive index layer was laminated on the 1 st protective film via the 1 st adhesive layer. The layer structure of the obtained laminate (9) was black acrylic plate/ethanol/high refractive index layer/1 st lamination layer/1 st protective film/3 rd lamination layer/polarizer (2)/4 th lamination layer/moth-eye film. The results obtained by measuring the stimulus value Y of the laminate (9) are shown in table 2.

TABLE 2

As is clear from the results shown in tables 1 and 2, when the in-plane retardation value of the 1 st retardation layer is in the range of 80nm to 170nm, the stimulus value Y becomes small, and the reflected light incident on the light receiving element of the display unit can be reduced. In addition, it is clear that even when the transmittance Ty of the visibility correction monomer of the polarizing plate included in the laminate is large, the stimulus value Y can be reduced, and the reflected light incident on the light receiving element of the display unit can be reduced.

Description of the reference numerals

1 to 4 display devices, 11 linear polarizing layers, 12 1 st protective film, 13 rd phase difference layer, 21 st bonding layer, 22 nd bonding layer, 23 rd bonding layer, 24 th bonding layer, 25 th bonding layer, 26 th bonding layer, 31 st phase difference layer, 32 nd phase difference layer, 40 display unit, 41 display element, 42 light receiving sensor, 45 high refractive index layer, 51 to 54 optical laminate.

Claims

1. A display device, which is used for displaying a display image,

which comprises a high refractive index layer, a 1 st phase difference layer, a linear polarization layer and a display unit in order from the visual side,

the high refractive index layer has a refractive index of 1.60 or more,

the display unit has a display element and a light receiving sensor,

2. The display device according to claim 1, wherein,

the 1 st retardation layer covers the entire surface of the linear polarization layer on the viewing side in plan view.

3. The display device according to claim 1 or 2, wherein,

the visibility-modifying monomer transmittance of the linear polarization layer is 42% or more.

4. The display device according to claim 1 or 2, wherein,

the angle formed by the slow axis of the 1 st phase difference layer and the absorption axis of the linear polarization layer is 10 DEG to 80 deg.

5. The display device according to claim 1 or 2, wherein,

the in-plane phase difference value at the wavelength 550nm of the 1 st phase difference layer is 80nm or more and 170nm or less.

6. The display device according to claim 5, wherein,

the 1 st phase difference layer has inverse wavelength dispersibility.

7. The display device according to claim 5, further comprising a 2 nd retardation layer between the high refractive index layer and the linearly polarizing layer,

the thickness direction phase difference value of the 2 nd phase difference layer at the wavelength of 550nm is more than-140 nm and less than-20 nm.

8. The display device according to claim 1 or 2, wherein,

the stimulus value Y of the reflected light of the outgoing light from the display element when the high refractive index layer is reflected is 3.45% or more and 4.54% or less.

9. The display device according to claim 1 or 2, wherein,

the light receiving sensor can detect light with a wavelength of 320nm to 4000 nm.

10. The display device according to claim 1 or 2, wherein,

the outgoing light from the display element is light having a wavelength of 320nm to 4000 nm.

11. The display device according to claim 1 or 2, further comprising a 3 rd phase difference layer between the linearly polarizing layer and the display unit.

12. An optical laminate of a substrate and a substrate,

which comprises a high refractive index layer, a 1 st phase difference layer and a linear polarization layer in sequence,

The refractive index of the high refractive index layer is 1.60 or more.

13. The optical stack according to claim 12, wherein,

14. The optical stack according to claim 12 or 13, wherein,

15. The optical stack according to claim 12 or 13, wherein,

16. The optical stack according to claim 12 or 13, wherein,

17. The optical stack according to claim 12 or 13, wherein,

the 1 st phase difference layer has inverse wavelength dispersibility.

18. The optical laminate according to claim 12 or 13, further having a 2 nd phase difference layer between the high refractive index layer and the linear polarization layer,

19. The optical stack according to claim 12 or 13, wherein,

the linear polarization layer further has a 3 rd retardation layer on the opposite side of the 1 st retardation layer side.