Display device and optical laminate

Abstract

The present invention provides a display device (1) that can suppress reflected light reflected from a high refractive index layer (45) from incident on a light sensor (42), and also provides an optical laminate (51) that can be used in the display device. [Solution] The display device (1) of the present invention comprises, in sequence from the recognition side, a high refractive index layer (45), a first phase retardation layer (31), a linear polarizing layer (11), and a display unit (40). The refractive index of the high refractive index layer (45) is 1.60 or higher. The display unit (40) comprises a display element (41) and a light sensor (42). The first phase retardation layer (31) and the linear polarizing layer (11) are laminated to cover the display element (41) and the light sensor (42).

Description

Technical Field

[0001] The present invention relates to a display device, and more particularly to an optical laminate used in the display device. Prior Art

[0002] A polarizing plate including a linear polarizing layer is widely used as a polarizing light supply element, a polarizing light detection element, and a suppressor of the emission of reflected light reflected by a display element to the outside in a display device such as a liquid crystal display device or an organic electroluminescence (EL) display device. Display devices equipped with a polarizing plate have also been extended to mobile devices such as notebook personal computers, smart phones, and tablet terminal devices. In Japanese Patent Document 1, from the viewpoints of expanding the display area in the display surface of a mobile device such as a smart phone and designability, for example, in a plan view, it is described that a non-display area is provided by cutting the edge of the display area into a concave shape.

[0003] The non-display area provided in the above concave shape usually does not have a display element and a polarizing plate. Therefore, by arranging various sensors such as a camera lens and a light receiving sensor in the non-display area, it is possible to hardly cause an adverse effect on the camera performance and the sensitivity of the sensor. [Prior Art Documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2019-219528 Summary of the Invention Problems to be Solved by the Invention

[0005] In order to further expand the display area on the display surface, it is required to reduce the non-display area. At this time, it is conceivable to arrange various sensors such as a light receiving sensor in the display area provided with a display element and a polarizing plate. If a light receiving sensor is arranged in the display area, the emitted light from the display element is likely to be reflected by the high refractive index layer disposed on the recognition side of the polarizing plate and enter the light receiving sensor. The reflected light incident on the light receiving sensor is likely to cause a failure of the light receiving sensor.

[0006] An object of the present invention is to provide a display device that can suppress the reflected light reflected by the high refractive index layer from entering the light receiving sensor even when a high refractive index layer is provided on the recognition side, and an optical laminate that can be used in the display device. Means for Solving the Problems

[0007] The present invention provides the following display device. [1] A display device, comprising, from the recognition side, a high refractive index layer, a first phase difference layer, a linear polarizing layer, and a display unit in sequence, and The aforementioned high refractive index layer has a refractive index of 1.60 or higher. The aforementioned display unit includes a display element and a light sensor. The aforementioned first phase difference layer and the aforementioned linear polarization layer are stacked in such a way that they cover the aforementioned display element and the aforementioned light sensor. [2] As described in [1], in a plan view, the first phase difference layer covers the entire surface of the identification side of the linear polarizing layer. [3] The display device as described in [1] or [2], wherein the transmittance of the aforementioned linear polarizing layer is 42% or more. [4] The display device described in any one of [1] to [3], wherein the angle formed by the slow axis of the first phase difference layer and the absorption axis of the linear polarizing layer is 10° or more and 80° or less. [5] The display device as described in any one of [1] to [4], wherein the aforementioned first phase difference layer has an in-plane phase difference value of 80 nm or more and 170 nm or less at a wavelength of 550 nm. [6] The display device as described in [5], wherein the aforementioned first phase difference layer has inverse wavelength dispersion. [7] The display device as described in [5] or [6] further comprises a second phase difference layer between the aforementioned high refractive index layer and the aforementioned linear polarizing layer. The aforementioned second phase difference layer is deposited to cover the aforementioned display element and the aforementioned light sensor. The phase difference value of the aforementioned second phase difference layer in the thickness direction at a wavelength of 550nm is greater than -140nm and less than -20nm. [8] The display device as described in any one of [1] to [7], wherein the stimulus value Y of the reflected light when the emitted light from the aforementioned display element is reflected by the aforementioned high refractive index layer is more than 3.45% and less than 4.54%. [9] The display device described in any one of [1] to [8], wherein the aforementioned light sensor is capable of detecting light with a wavelength of 320 nm or more and 4000 nm or less.

[10] The display device as described in any one of [1] to [9], wherein the emitted light from the aforementioned display element has a wavelength of 320 nm or more and 4000 nm or less.

[11] The display device according to any one of [1] to

[10] further has a third retardation layer between the linear polarizing layer and the display unit.

[0008] The present invention provides the following optical laminate.

[12] An optical laminate having, in order, a high refractive index layer, a first retardation layer, and a linear polarizing layer, and the refractive index of the high refractive index layer is 1.60 or more.

[13] The optical laminate according to

[12] , wherein, in a plan view, the first retardation layer covers the entire surface on the identification side of the linear polarizing layer.

[14] The optical laminate according to

[12] or

[13] , wherein the visual sensitivity correction monomer transmittance of the linear polarizing layer is 42% or more.

[15] The optical laminate according to

[12] or

[13] , wherein the angle formed by the slow axis of the first retardation layer and the absorption axis of the linear polarizing layer is 10° or more and 80° or less.

[16] The optical laminate according to

[12] or

[13] , wherein the in-plane retardation value of the first retardation layer at a wavelength of 550 nm is 80 nm or more and 170 nm or less.

[17] The optical laminate according to

[12] or

[13] , wherein the first retardation layer has inverse wavelength dispersion.

[18] The optical laminate according to

[12] or

[13] further has a second retardation layer between the high refractive index layer and the linear polarizing layer, the thickness direction retardation value of the second retardation layer at a wavelength of 550 nm is -140 nm or more and -20 nm or less.

[19] The optical laminate according to

[12] or

[13] , wherein, on the side opposite to the first retardation layer side of the linear polarizing layer, a third retardation layer is further provided. Advantageous Effects of the Invention

[0009] In the display device according to the present invention, the reflected light reflected by the high refractive index layer can be suppressed from entering the light receiving sensor. Further, in the optical laminate according to the present invention, the above-described display device of the present invention can be provided. Brief Explanation of the Drawings

[0010] FIG. 1 schematically shows a schematic cross-sectional view of a display device according to an embodiment of the present invention. FIG. 2 schematically shows a schematic cross-sectional view of a display device according to another embodiment of the present invention. Figure 3 is a schematic cross-sectional view of a display device in another embodiment of the present invention. Figure 4 is a schematic cross-sectional view of a display device in another embodiment of the present invention. Implementation [The form in which the invention is implemented]

[0011] The following describes preferred embodiments of the display device and optical laminate with reference to the drawings. In the drawings, components that are the same as those previously described are given the same reference numerals and their descriptions are omitted. [Implementation Type 1]

[0012] (Display device and optical laminate) Figures 1 and 2 are schematic cross-sectional views illustrating a display device according to one embodiment of the present invention. In Figures 1 and 2, the upper side is the identification side. As shown in Figures 1 and 2, the display devices 1 and 2 of this embodiment sequentially include a high refractive index layer 45, a first retardation layer 31, a linear polarizing layer 11, and a display unit 40 from the identification side. Among these, the high refractive index layer 45, the first retardation layer 31, and the linear polarizing layer 11 constitute optical laminates 51 and 52. The refractive index of the high refractive index layer 45 is 1.60 or higher, preferably 1.75 or higher, more preferably 1.80 or higher, typically 2.70 or lower, preferably 2.40 or lower, more preferably 2.30 or lower, and even more preferably 2.10 or lower. The refractive index of the high refractive index layer 45 can be measured by the method described in the embodiments below.

[0013] The display unit 40 includes a display element 41 and a light sensor 42. As shown in Figures 1 and 2, the display unit 40 may have a structure in which the light sensor 42 is located on the recognition side layer of the display element 41, or it may have a structure in which the light sensor 42 is located on the side layer opposite to the recognition side of the display element 41. Alternatively, the light sensor 42 may be embedded in a through hole or recess provided in the display element 41. Since the area of ​​the display element 41 in the display unit 40 can be set as the display area of ​​the display devices 1 and 2, from the viewpoint of expanding the display area, in the plan view of the display unit 40, it is preferable that the area of ​​the display element 41 exists in a manner that surrounds the light sensor 42.

[0014] In display devices 1 and 2, the first phase retardation layer 31 and the linear polarizing layer 11 are laminated to cover the display element 41 and the light sensor 42. Preferably, the first phase retardation layer 31 and the linear polarizing layer 11 cover the entire surface of the recognition side of the display unit 40, that is, they are laminated to cover the entire surface of the recognition side of the display element 41 and the light sensor 42. As described above, by providing the linear polarizing layer 11, in a plan view, the area of ​​the display element 41 surrounding the light sensor 42 is covered by the linear polarizing layer 11, thus easily expanding the display area of ​​display devices 1 and 2. The first phase retardation layer 31 is laminated to cover the display element 41 and the light sensor 42; in a plan view, it can cover the entire linear polarizing layer 11 or only a portion of it. The plan view shape of the first phase retardation layer 31 can be the same as or different from the plan view shape of the linear polarizing layer 11.

[0015] In display devices 1 and 2, images are displayed using light emitted from display element 41. As shown by the arrow in Figure 1, a portion of the light emitted from display element 41 may be reflected by the high refractive index layer 45 and incident on the light sensor 42. Especially in the plan view of display unit 40, for example, when the area of ​​the light sensor 42 is adjacent to and near the area of ​​display element 41, the reflected light reflected by the high refractive index layer 45 can easily incident on the light sensor 42. If the reflected light incidents on the light sensor 42, it can easily cause a malfunction of the light sensor 42. In display devices 1 and 2 of this embodiment, a first phase retardation layer 31 is formed by the recognition side layer covering the linear polarization layer 11 of display element 41 and light sensor 42. The reflected light reflected by the high refractive index layer 45 is incident on the first phase retardation layer 31, and its phase is changed by passing through the first phase retardation layer 31. Therefore, at least a portion of the reflected light through the first phase difference layer 31 is readily absorbed by the linear polarization layer 11. This reduces the amount of reflected light incident on the photosensor 42, thereby suppressing malfunctions of the photosensor 42.

[0016] The transmittance of the linear polarizing layer 11 with a sensitivity correction element is preferably 42% or higher, more preferably 43% or higher, and can be 45% or higher. If the transmittance of the linear polarizing layer 11 with a sensitivity correction element increases, the amount of reflected light passing through the linear polarizing layer 11 increases, which can easily lead to malfunctions of the light sensor 42. When the display devices 1 and 2 of this embodiment use a linear polarizing layer 11 with a high transmittance of the sensitivity correction element, the amount of reflected light incident on the light sensor 42 can be suppressed, and malfunctions of the light sensor 42 can be suppressed. The transmittance of the linear polarizing layer 11 with a sensitivity correction element can be measured according to the method described in the embodiments below.

[0017] The first phase difference layer 31 only needs to have a phase difference, but it is preferable to have an in-plane phase difference value Re(550) of 80 nm to 170 nm at a wavelength of 550 nm. The in-plane phase difference value Re(550) of the first phase difference layer 31 is more preferably 100 nm or more, especially 130 nm or more, and can be 135 nm or more. It is also more preferably 160 nm or less, and even more preferably 150 nm or less. The in-plane phase difference value Re(550) of the first phase difference layer 31 can be measured according to the method described in the embodiments below.

[0018] When the first phase retardation layer 31 has an in-plane phase difference value Re (550) within the aforementioned range, the light emitted from the display element 41 in the display devices 1 and 2 is converted into elliptically polarized light if it passes through the first phase retardation layer 31. The reflected light (circularly polarized light) reflected by the high refractive index layer 45 is converted into linearly polarized light by passing through the first phase retardation layer 31. In this way, the reflected light passing through the first phase retardation layer 31 is easily absorbed by the linear polarization layer 11, thereby further suppressing the amount of reflected light incident on the photosensitive sensor 42.

[0019] When the in-plane phase difference value Re(550) of the first phase difference layer 31 is within the above range, the angle formed by the absorption axis of the linear polarizing layer 11 and the slow axis of the first phase difference layer 31 is preferably in the range of 10° to 80°. The above angle can be 30° or more, more preferably 40° or more. Furthermore, the above angle can be 60° or less, more preferably 50° or less.

[0020] The first phase difference layer 31, with an in-plane phase difference value Re(550) within the aforementioned range, preferably has reverse wavelength dispersion. This broadens the wavelength range of reflected light absorbed by the linear polarizing layer 11, thereby suppressing the amount of reflected light of various wavelengths incident on the photosensitive sensor 42.

[0021] In 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% to 4.54%. The stimulus value Y of the reflected light is the ratio of the light intensity of the reflected light to the light intensity of the light emitted from the display element 41. The smaller the stimulus value Y, the smaller the amount of reflected light reflected by the high refractive index layer 45, indicating that it is less likely to cause a malfunction of the photosensor 42. The stimulus value Y of the reflected light can be measured according to the method described in the embodiments below. The stimulus value Y of the reflected light can be 3.48% or more, or 3.50% or more, or 4.30% or less, or 4.10% or less, or 3.90% or less, or 3.76% or less.

[0022] In display devices 1 and 2 where the emitted light stimulus value Y is within the aforementioned range, the amount of reflected light incident on the light sensor 42 is easily suppressed. When the emitted light stimulus value Y is less than the aforementioned range, it is assumed that the refractive index of the high refractive index layer 45 is low, or the transmittance of the sensitivity correction monomer of the linear polarizing layer 11 is low. Therefore, it is assumed that in display devices where the emitted light stimulus value Y is less than the aforementioned range, the amount of reflected light incident on the light sensor 42 is low, and malfunctions of the light sensor 42 are less likely to occur. Conversely, in display devices where the emitted light stimulus value Y is greater than the aforementioned range, the amount of reflected light incident on the light sensor 42 is high, and malfunctions of the light sensor 42 are more likely to occur.

[0023] (Layer structure of display devices and optical laminates) The following describes the layers that the display devices 1 and 2 and the optical laminates 51 and 52 may have, in addition to the layers described above.

[0024] As shown in Figures 1 and 2, the display devices 1 and 2 and the optical stacks 51 and 52 preferably have a first bonding layer 21 between the high refractive index layer 45 and the first retardation layer 31. The first bonding layer 21 can be in direct contact with the high refractive index layer 45 and the first retardation layer 31.

[0025] In addition to the high refractive index layer 45, display devices 1 and 2 and optical stacks 51 and 52 may have one or more second refractive index layers (not shown). The refractive index of the second refractive index layer may be set to the refractive index range described in the high refractive index layer 45. The second refractive index layer may be disposed on the identification side of the high refractive index layer 45, or it may be disposed between the high refractive index layer 45 and the first phase retardation layer 31. In this case, display devices 1 and 2 and optical stacks 51 and 52 may have an adhesive layer (adhesive layer or bonding agent layer described later) between the high refractive index layer 45 and the second refractive index layer, and this adhesive layer may be in direct contact with the high refractive index layer 45 and the second refractive index layer. When display devices 1 and 2 and optical stacks 51 and 52 have a second refractive index layer between the high refractive index layer 45 and the first phase retardation layer 31, the first adhesive layer 21 may be in direct contact with the first phase retardation layer 31 and the second refractive index layer.

[0026] The display devices 1 and 2 and the optical stacks 51 and 52 preferably have a second bonding layer 22 between the first retardation layer 31 and the linear polarization layer 11. The second bonding layer 22 can be in direct contact with the first retardation layer 31 and the linear polarization layer 11.

[0027] As shown in Figures 1 and 2, the display devices 1 and 2 and the optical laminates 51 and 52 may have a first protective film 12 between the first retardation layer 31 and the linear polarizing layer 11. The first protective film 12 may be a layer used to protect the surface of the linear polarizing layer 11 on the identification side. The first protective film 12 and the linear polarizing layer 11 may constitute a linear polarizing plate. When the display devices 1 and 2 and the optical laminates 51 and 52 have the first protective film 12, the second bonding layer 22 may be in direct contact with the first retardation layer 31 and the first protective film 12.

[0028] When the display devices 1 and 2 and the optical laminates 51 and 52 have a first protective film 12, the display devices 1 and 2 and the optical laminates 51 and 52 can directly contact the first protective film 12 and the linear polarizing layer 11. Preferably, a third bonding layer 23 is provided between the first protective film 12 and the linear polarizing layer 11. The third bonding layer 23 can form a linear polarizing plate, and preferably it is in direct contact with the first protective film 12 and the linear polarizing layer 11.

[0029] Display devices 1 and 2 may have a fourth bonding layer 24 between the linear polarizing layer 11 and the display unit 40 (the side of the linear polarizing layer 11 opposite to the side of the first phase difference layer 31). As shown in FIG1, the linear polarizing layer 11 and the display unit 40 may be in direct contact with the fourth bonding layer 24. As shown in FIG1 and FIG2, the aforementioned fourth bonding layer 24 may have optical laminates 51 and 52.

[0030] The display devices 1 and 2 and the optical stacks 51 and 52 may have a second protective film (not shown) between the linear polarizing layer 11 and the display unit 40 (the side of the linear polarizing layer 11 opposite to the side of the first phase difference layer 31). The second protective film may be a layer used to protect the surface of the linear polarizing layer 11 opposite to the recognition side, and the second protective film and the linear polarizing layer 11 may constitute a linear polarizing plate. When the display devices 1 and 2 and the optical stacks 51 and 52 have the second protective film, the second protective film and the linear polarizing layer 11 may be in direct contact, or an adhesive layer (adhesive layer or bonding agent layer described later) may be provided between the second protective film and the linear polarizing layer 11. This adhesive layer may constitute a linear polarizing plate, and preferably it is in direct contact with the second protective film and the linear polarizing layer 11. At this time, the fourth adhesive layer 24 may be provided between the second protective film and the display unit 40, or it may be in direct contact with the second protective film and the display unit 40.

[0031] As shown in Figure 2, the display device 2 and the optical stack 52 may have a third phase retardation layer 13 between the linear polarizing layer 11 and the display unit 40 (the side of the linear polarizing layer 11 opposite to the side of the first phase retardation layer 31). In this case, the display device 2 and the optical stack 52 may have a fifth bonding layer 25 between the linear polarizing layer 11 and the third phase retardation layer 13, and the linear polarizing layer 11 and the third phase retardation layer 13 may be in direct contact with the fifth bonding layer 25. When the display device 2 and the optical stack 52 have a second protective film, the fifth bonding layer 25 is disposed between the second protective film and the third phase retardation layer 13, and may be in direct contact with both the second protective film and the third phase retardation layer 13. In the display device 2 with the third phase retardation layer 13, the fourth bonding layer 24 may be disposed between the third phase retardation layer 13 and the display unit 40, and may also be in direct contact with both the third phase retardation layer 13 and the display unit 40. In the optical stack 52 having the third phase retardation layer 13, the fourth bonding layer 25 can be in direct contact with the third phase retardation layer 13. The linear polarizing layer 11 and the third phase retardation layer 13 are preferably arranged to form a circular polarizing plate. The third phase retardation layer 13 is preferably a λ / 4 phase retardation layer, and more preferably a λ / 4 phase retardation layer with reverse wavelength dispersion.

[0032] The display device 2 and the optical stack 52 are located between the linear polarizing layer 11 and the display unit 40 (the side of the linear polarizing layer 11 opposite to the side of the first phase retardation layer 31). In addition to the third phase retardation layer 13, it may have one or more fourth phase retardation layers (not shown). The fourth phase retardation layer may be located between the linear polarizing layer 11 and the third phase retardation layer 13, or between the third phase retardation layer 13 and the display unit 40 (the side of the third phase retardation layer 13 opposite to the side of the linear polarizing layer 11). In this case, an adhesive layer (adhesive layer or bonding agent layer described later) may be provided between the third phase retardation layer 13 and the fourth phase retardation layer, which can directly contact the third phase retardation layer 13 and the fourth phase retardation layer. When the display device 2 and the optical stack 52 have a fourth phase retardation layer between the linear polarizing layer 11 and the third phase retardation layer 13, the fifth adhesive layer 25 can directly contact the linear polarizing layer 11 and the fourth phase retardation layer. When the display device 2 has a fourth phase retardation layer between the third phase retardation layer 13 and the display unit 40, the fourth bonding layer 24 can directly contact the fourth phase retardation layer and the display unit 40. When the optical laminate 52 has a third phase retardation layer on the side opposite to the linear polarizing layer 11 of the third phase retardation layer 13, the fourth phase retardation layer can directly contact the fourth bonding layer. The linear polarizing layer 11, the third phase retardation layer 13, and the fourth phase retardation layer are preferably configured to form a circular polarizing plate. The fourth phase retardation layer constituting the circular polarizing plate is preferably a λ / 2 phase retardation layer or a positive C layer. [Implementation Type 2]

[0033] Figures 3 and 4 are schematic cross-sectional views illustrating other embodiments of the display device of the present invention. In Figures 3 and 4, the upper side is the identification side. The display devices 3 and 4 and optical stacks 53 and 54 of this embodiment have a second phase difference layer 32 between the high refractive index layer 45 and the linear polarizing layer 11. Since this is different from the display devices 1 and 2 and optical stacks 51 and 52 described in the previous embodiments, this point will be described below.

[0034] In display devices 3 and 4, the second phase difference layer 32 is deposited to cover the display element 41 and the light sensor 42. Preferably, the second phase difference layer 32 is deposited to cover the entire surface of the recognition side of the display unit 40, that is, to cover the entire surface of the recognition side of the display element 41 and the light sensor 42.

[0035] The display devices 3 and 4 and optical stacks 53 and 54 shown in Figures 3 and 4 have a second retardation layer 32 between the high refractive index layer 45 and the first retardation layer 31. Preferably, the second retardation layer 32 covers the entire first retardation layer 31 in a plan view, and the plan view shape of the second retardation layer 32 is more preferably the same as the plan view shape of the first retardation layer 31.

[0036] The second phase difference layer 32 only needs to have a phase difference, preferably having a phase difference value Rth(550) in the thickness direction at a wavelength of 550nm that is between -140nm and -20nm. The phase difference value Rth(550) in the thickness direction of the second phase difference layer 32 can be greater than -140nm, greater than -120nm, greater than -100nm, or greater than -90nm, or less than -20nm, less than -30nm, less than -40nm, or less than -50nm.

[0037] The phase difference value Rth(550) in the thickness direction of the second phase difference layer 32 is calculated according to equation (i). Rth(550)=[{(nx+ny) / 2}-nz]×d (i) In formula (i), The nx system represents the principal refractive index at an in-plane wavelength of 550 nm in the second phase retardation layer 32. Let ny be the refractive index at a wavelength of 550 nm in the same plane as nx, along a direction orthogonal to nx. Let nz be the refractive index at a wavelength of 550 nm along the thickness direction of the second retardation layer 32. When nx = ny, nx can be set as the refractive index in any direction within the plane of the second retardation layer 32. The film thickness of the second phase difference layer 32 in the d-system.

[0038] By incorporating a second phase retardation layer 32 in display devices 3 and 4, as indicated by the arrow in Figure 3, the amount of light incident even on obliquely incident reflected light from the light received by the photosensitive sensor 42 can be reduced. The obliquely incident reflected light, in the plan view of display unit 40, is mainly the light emitted from a region far from the photosensitive sensor 42 in display element 41 and reflected by the high refractive index layer 45. The amount of light incident on obliquely is easily reduced when the phase difference value Rth(550) in the thickness direction of the second phase retardation layer 32 is within the aforementioned range. This further suppresses malfunctions of the photosensitive sensor 42.

[0039] As shown in Figures 3 and 4, the first bonding layer 21 can be disposed between the high refractive index layer 45 and the second phase retardation layer 32, or it can be in direct contact with the high refractive index layer 45 and the second phase retardation layer 32. The display devices 3 and 4 and the optical stacks 53 and 54 have a sixth bonding layer 26 between the second phase retardation layer 32 and the first phase retardation layer 31, and the second phase retardation layer 32 and the first phase retardation layer 31 are preferably in direct contact with the sixth bonding layer 26.

[0040] The display devices 3 and 4 and the optical stacks 53 and 54 shown in Figures 3 and 4 illustrate the case where a second retardation layer 32 is present between the high refractive index layer 45 and the first retardation layer 31. However, the second retardation layer 32 is not limited to being present between the high refractive index layer 45 and the linear polarizing layer 11. For example, the second retardation layer 32 may be disposed between the first retardation layer 31 and the linear polarizing layer 11. In this case, the second retardation layer 32 preferably covers the entire linear polarizing layer 11. The planar shape of the second retardation layer 32 is preferably the same as the planar shape of the first retardation layer 31.

[0041] When the display devices 3 and 4 and the optical stacks 53 and 54 have a second phase retardation layer 32 between the first phase retardation layer 31 and the linear polarizing layer 11, the display devices 3 and 4 and the optical stacks 53 and 54 may have a sixth bonding layer 26 between the second phase retardation layer 32 and the first phase retardation layer 31. Furthermore, the second bonding layer 22 may be disposed between the second phase retardation layer 32 and the linear polarizing layer 11; for example, the second bonding layer 22 may be in direct contact with the second phase retardation layer 32 and the first protective film 12.

[0042] The following provides a more detailed description of the display device and the layers constituting the display device as described above.

[0043] (Display device) The aforementioned display device can be used as a liquid crystal display device or an organic EL (electroluminescent) display device. The display device can be a mobile terminal such as a smartphone or tablet computer. The display device can be a flexible, bendable display.

[0044] The plan view of the display area of ​​the display device is not particularly limited in shape, and can be a rectangle, a square, a polygon other than a rectangle and a square, or a rounded shape with rounded corners (having an R shape). The rectangular, square, the aforementioned polygons, or rounded display areas may have through holes for mounting cameras, etc.

[0045] (Display element) The display element can be a liquid crystal display element or an organic EL display element. A liquid crystal display element, for example, may have a liquid crystal cell with a liquid crystal layer sandwiched between two unit substrates and a backlight. An organic EL display element, for example, may have a light-emitting layer and electrodes.

[0046] The light emitted from the display element is preferably light with a wavelength between 320nm and 4000nm, and even better if it is light with a wavelength between 380nm and 780nm (visible light region). It can be light with a wavelength between 380nm and 720nm.

[0047] (Light sensor) A light sensor detects incident light. A light sensor can be an illuminance sensor to detect the ambient light level around a display device, a proximity sensor to detect the approach of an object, or a camera, etc. Preferably, the light sensor can detect light with wavelengths between 320 nm and 4000 nm; more preferably, it can detect light with wavelengths between 380 nm and 780 nm (visible light region) and / or light with wavelengths between 780 nm and 4000 nm (infrared light region).

[0048] (Touch sensor panel) Display devices and optical laminates may include touch sensor panels. Touch sensor panels can detect the location of touches made by a user's finger or other fingers. Examples of touch sensor panels include resistive film, capacitive coupling, photosensor, ultrasonic, electromagnetic induction coupling, and surface acoustic wave touch sensor panels. Among these, resistive film and capacitive coupling touch sensor panels are particularly suitable.

[0049] In a display device and optical laminate, a touch sensor panel can be disposed on the recognition side of the linear polarizing layer (the side of the first phase difference layer of the linear polarizing layer), or on the side of the linear polarizing layer opposite to the recognition side. When the touch sensor panel is disposed on the recognition side of the linear polarizing layer, the touch sensor panel can form a high refractive index layer as described later. When the touch sensor panel is disposed on the side of the linear polarizing layer opposite to the recognition side, the touch sensor panel is preferably disposed between the linear polarizing layer and the display unit.

[0050] (High refractive index layer) The high refractive index layer is any layer with a refractive index within the range specified in this embodiment (1.60 or higher), and there are no particular limitations. If the high refractive index layer has the aforementioned refractive index, it can be the front panel of a display device or a touch sensor panel. The high refractive index layer can have a single-layer structure or a multi-layer structure. When the high refractive index layer has a multi-layer structure, as long as the high refractive index layer has the aforementioned refractive index, the high refractive index layer may include layers with a refractive index less than 1.60.

[0051] The front panel can form the front surface of the display device. The front panel can be any plate-like material that allows light to pass through; for example, it can be a resin plate, resin film, glass plate, or glass film. The front panel can be a single-layer structure or a multi-layer structure. The refractive index of the front panel can be between 1.45 and 1.9.

[0052] The polymer constituting the resin board or resin film can be any resin that allows light to pass through, and there are no particular limitations. Examples of such polymers include: triacetyl cellulose, acetyl cellulose butyrate, ethylene-vinyl acetate copolymer, propylene cellulose, butyl cellulose, acetylpropylene cellulose, polyester, polystyrene, polyamide, polyetheramide, poly(meth)acrylic acid, polyamide, polyether etherketone, polyether etherketone, polyether etherketone, poly(meth)acrylate, polyethylene, polypropylene, polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetal, polyetherketone, polyetheretherketone, polyether etherketone, poly(meth)acrylate, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyamideamide, etc. These polymers can be used alone or in mixtures of two or more. In this specification, (meth)acrylic acid refers to acrylic acid and / or methacrylic acid, and (meth)acrylate refers to acrylate and / or methacrylate.

[0053] When the front panel is a resin film, the front panel may have a hard coating on at least one side of the resin film. Examples of hard coatings include, for example, a hardened layer of a UV-curable resin. Examples of UV-curable resins include, for example, monofunctional (meth)acrylic resins, polyfunctional (meth)acrylic resins, polyfunctional (meth)acrylic resins with a dendritic polymer structure, etc.; polysiloxane resins; polyester resins; ethyl carbamate resins; amide resins; epoxy resins, etc. To improve strength, the hard coating may contain additives. Additives are not particularly limited and may include inorganic microparticles, organic microparticles, or mixtures thereof. When hard coatings are present on both sides of the resin film, the composition and thickness of each hard coating may be the same or different.

[0054] When the front panel is a glass plate or glass film, it is better to use tempered glass for monitors.

[0055] The touch sensor panel constituting the high refractive index layer can be exemplified by the touch sensor panels mentioned above. When the touch sensor panel constitutes the high refractive index layer, the refractive index of the touch sensor panel is 1.60 or higher, preferably 1.70 or higher, more preferably 1.90 or higher, typically 2.70 or lower, preferably 2.60 or lower, and more preferably 2.40 or lower.

[0056] (1st phase difference layer, 2nd phase difference layer, 3rd phase difference layer, 4th phase difference layer) The first phase retardation layer, the second phase retardation layer, the third phase retardation layer, and the fourth phase retardation layer (hereinafter, sometimes collectively referred to as "phase retardation layers") can be extended films or hardened layers containing polymeric liquid crystal compounds.

[0057] When the phase retardation layer is an extended film, the extended film system can be any known prior art, and can be one in which the phase retardation is imparted by uniaxial or biaxial extension of the resin film. The resin film system can be cellulose membranes such as triacetyl cellulose and diacetyl cellulose, polyester membranes such as polyethylene terephthalate, polyethylene isophthalate, and polybutylene terephthalate, acrylic resin membranes such as poly(methyl methacrylate) and poly(ethyl methacrylate), polycarbonate membranes, polyether resin membranes, polyurethane membranes, polyimide membranes, polyolefin membranes, polyvinyl chloride membranes, etc., but is not limited to these.

[0058] When the retardation layer is an extended film, the thickness of the retardation layer is usually between 5 μm and 200 μm, preferably between 10 μm and 80 μm, and even more preferably between 40 μm and 200 μm.

[0059] When the phase retardation layer comprises the aforementioned hardened layer, a polymerizable liquid crystal compound may be used, which is a conventionally known polymerizable liquid crystal compound. The polymerizable liquid crystal compound is a compound having at least one polymerizable group and exhibiting liquid crystal properties.

[0060] There is no particular limitation on the type of polymerizable liquid crystal compound; rod-shaped liquid crystal compounds, disk-shaped liquid crystal compounds, and mixtures thereof can be used. A phase difference is manifested by curing a hardened layer formed by polymerizing the liquid crystal compound in a state of orientation suitable for the liquid crystal compound. When a rod-shaped liquid crystal compound is oriented horizontally or vertically relative to the plane of the display device, its optical axis is aligned with its long axis. When a disk-shaped liquid crystal compound is oriented, its optical axis exists in a direction orthogonal to the disk surface of the liquid crystal compound. Rod-shaped liquid crystal compounds may be suitable for use as described in, for example, Japanese Patent Application Publication No. 11-513019 (claim 1, etc.). The disc-shaped polymeric liquid crystal compound is suitable for use with respect to the descriptions in Japanese Patent Application Publication No. 2007-108732 (paragraphs

[0020] to

[0067] , etc.) and Japanese Patent Application Publication No. 2010-244038 (paragraphs

[0013] to

[0108] , etc.).

[0061] The polymerizable group in a polymerizable liquid crystal compound refers to a group that participates in the polymerization reaction, preferably a photopolymerizable group. A photopolymerizable group refers to a group that can participate in the polymerization reaction through active free radicals or acids generated from a photopolymerization initiator. Examples of polymerizable groups include vinyl, ethoxy, 1-chlorovinyl, isopropenyl, 4-vinylphenyl, (meth)acryloxy, ethylene oxide, oxybutyl, styryl, and allyl. Among these, (meth)acryloxy, ethoxy, ethylene oxide, and oxybutyl are preferred, with acryloxy being even more preferred. The liquid crystallization property of a polymerizable liquid crystal compound can be thermotropic or lyotropic. If thermotropic liquid crystals are classified according to their degree of order, they can be nematic or lamellar liquid crystals. When forming a hardened layer of a polymerizable liquid crystal compound using two or more types of polymerizable liquid crystal compounds, it is preferable that at least one type has two or more polymerizable groups within its molecule. In this specification, (meth)acrylic acid refers to acrylonitrile and / or methacrylic acid.

[0062] When the retardation layer includes the aforementioned hardened layer, the retardation layer system may contain an alignment layer. The alignment layer system has an alignment limiting force that orients the polymeric liquid crystal compound in a desired direction. The alignment layer system may be a vertical alignment layer that orients the molecular axis of the polymeric liquid crystal compound perpendicular to the plane of the display device, a horizontal alignment layer that orients the molecular axis of the polymeric liquid crystal compound horizontally to the plane of the display device, or an inclined alignment layer that orients the molecular axis of the polymeric liquid crystal compound obliquely to the plane of the display device. When the retardation layer includes two or more alignment layers, the alignment layer systems may be identical or different from each other.

[0063] The alignment layer preferably possesses solvent resistance to dissolution during coating of liquid crystal layer forming compositions containing polymeric liquid crystal compounds, and heat resistance to heat treatments used to remove solvents or orient polymeric liquid crystal compounds. Examples of alignment layers include alignment polymer layers formed from alignment polymers, photoalignment polymer layers formed from photoalignment polymers, and trench alignment layers having uneven patterns or multiple trenches on the layer surface.

[0064] The aforementioned curing layer system allows for the coating of a phase retardation layer forming composition, comprising a polymerizable liquid crystal compound, a solvent, and various additives as needed, onto an alignment layer to form a coating film. This coating film is then cured (hardened), thereby forming a cured layer of the polymerizable liquid crystal compound. Alternatively, the aforementioned composition can be coated onto a substrate layer to form a coating film, and a cured layer is formed by extending the coating film together with the substrate layer. In addition to the aforementioned polymerizable liquid crystal compound and solvent, the aforementioned composition system may also include polymerization initiators, reactive additives, leveling agents, polymerization inhibitors, etc. Known polymerizable liquid crystal compounds, solvents, polymerization initiators, reactive additives, leveling agents, polymerization inhibitors, etc., may be appropriately used.

[0065] The substrate layer can be a film formed of a resin material, such as the thermoplastic resin used in the instructions for use to form the first protective film described later. The thickness of the substrate layer is not particularly limited, but generally, from the perspective of strength and operability, a thickness of 1 to 300 μm or less is preferred, 20 to 200 μm is more preferred, and 30 to 120 μm is even more preferred. The substrate layer can be incorporated into the display device together with the cured layer of the polymeric liquid crystal compound, or the substrate layer can be peeled off, and only the cured layer of the polymeric liquid crystal compound, or the cured layer and the alignment layer, can be incorporated into the display device. When the substrate layer is incorporated into the display device together with the cured layer of the polymeric liquid crystal compound, the thickness of the substrate layer may be less than 30 μm, for example, it may be 25 μm or less.

[0066] When the phase retardation layer includes the aforementioned hardened layer, the thickness of the phase retardation layer is preferably 0.1 μm or more, more preferably 0.2 μm or more, and even more preferably 3 μm or less, and more preferably 2 μm or less.

[0067] (Linear polarizing layer) Linear polarizing layers possess the property of allowing linearly polarized light, which has a vibrational plane orthogonal to the absorption axis, to pass through when unpolarized light is incident. Linear polarizing layers can be polyvinyl alcohol-based resin films (hereinafter sometimes referred to as "PVA-based films") oriented by iodine adsorption, or films containing a liquid crystal polarizing layer formed by coating a substrate film with a composition comprising compounds exhibiting anisotropic absorption and liquid crystal properties. The compounds exhibiting anisotropic absorption and liquid crystal properties can be a mixture of anisotropic pigments and liquid crystal compounds, or pigments exhibiting anisotropic absorption and liquid crystal properties.

[0068] The linear polarizing layer is preferably a PVA-based film in which iodine is adsorbed and oriented. Examples of linear polarizing layers belonging to PVA-based films include: polyvinyl alcohol films, partially formaldehyde-modified polyvinyl alcohol films, and partially saponified films based on ethylene / vinyl acetate copolymers, which have undergone iodine dyeing and stretching treatments. If necessary, a washing step can be performed, which involves treating the dyed PVA-based film, in which iodine is adsorbed and oriented, with a boric acid aqueous solution, followed by washing away the boric acid aqueous solution. Known methods can be used in each step.

[0069] Polyvinyl alcohol (PVA) resins (hereinafter sometimes referred to as "PVA-based resins") can be manufactured by saponifying polyvinyl acetate (PVA) resins. Besides polyvinyl acetate homopolymers, PVA resins can also be copolymers of vinyl acetate with other monomers that can copolymerize with vinyl acetate. Examples of other monomers that can copolymerize with vinyl acetate include: unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides with ammonium groups.

[0070] The degree of saponification of PVA-based resins is typically around 85 to 100 moles, preferably above 98 moles. PVA-based resins can be modified; for example, aldehyde-modified polyvinyl formaldehyde or polyvinyl acetal can be used. The average degree of polymerization of PVA-based resins is typically around 1,000 to 10,000, preferably around 1,500 to 5,000. The degree of saponification and average degree of polymerization of PVA-based resins can be determined according to JIS K 6726 (1994). When the average degree of polymerization is below 1000, it is difficult to obtain good polarization performance; above 10,000, film processability deteriorates.

[0071] A method for manufacturing a linear polarizing layer belonging to a PVA-based film may include the following steps: preparing a substrate film, coating a solution of a resin such as a PVA-based resin onto the substrate film, and drying to remove the solvent, thereby forming a resin layer on the substrate film. Furthermore, a prepolymer layer may be pre-formed on the surface where the resin layer of the substrate film is formed. The substrate film may be a film made of a thermoplastic resin material described later as being used to form the first protective film. Examples of materials for the prepolymer layer include resins that crosslink the hydrophilic resin used in the linear polarizing layer.

[0072] Then, after adjusting the amount of water and other solvents in the resin layer as needed, the substrate film and resin layer are uniaxially stretched. Next, the resin layer is stained with iodine to allow the iodine to be adsorbed and oriented. Following this, a washing step is performed as needed, which involves treating the iodine-oriented resin layer with a boric acid aqueous solution and then washing away the boric acid solution. This process creates an iodine-oriented resin layer, i.e., a PVA-based film that becomes a linear polarizing layer. Known methods can be used in each step.

[0073] In the boric acid-containing aqueous solution used to treat iodine-adsorbed and oriented PVA membranes or resin layers, the amount of boric acid is typically about 2 to 15 parts by weight per 100 parts by weight of water, preferably 5 to 12 parts by weight. This boric acid-containing aqueous solution preferably contains potassium iodide. The amount of potassium iodide in the boric acid-containing aqueous solution is typically about 0.1 to 15 parts by weight per 100 parts by weight of water, preferably 5 to 12 parts by weight. The immersion time in the boric acid-containing aqueous solution is typically about 60 to 1200 seconds, preferably 150 to 600 seconds, and more preferably 200 to 400 seconds. The temperature of the boric acid-containing aqueous solution is typically above 50°C, preferably 50 to 85°C, and more preferably 60 to 80°C.

[0074] The uniaxial stretching of PVA-based films, substrate films, and resin layers can be performed before dyeing, during dyeing, during boric acid treatment after dyeing, or separately in multiple stages. The PVA-based films, substrate films, and resin layers can be uniaxially stretched in the MD direction (film transport direction). In this case, uniaxial stretching can be performed between rollers with different circumferential speeds, or uniaxial stretching can be performed using hot rollers. Furthermore, the PVA-based films, substrate films, and resin layers can be uniaxially stretched in the TD direction (perpendicular to the film transport direction). In this case, the so-called tenter frame method can be used. Moreover, the above stretching can be dry stretching performed in the atmosphere, or wet stretching performed while the PVA-based films or resin layers are swollen with solvent. To exhibit the performance of the linear polarizing layer, the stretching ratio is preferably 4 times or more, 5 times or more, and especially 5.5 times or more. There is no particular upper limit to the stretching ratio, but from the viewpoint of suppressing cracking, it is preferable to be 8 times or less.

[0075] The linear polarizing layer produced by the method of manufacturing a substrate film can be obtained by depositing a first protective film or a second protective film and then peeling off the substrate film. According to this method, the linear polarizing layer can be further thinned.

[0076] The thickness of the linear polarizing layer of PVA films is preferably above 1μm, but can be above 2μm or above 5μm. It is also preferred to be below 30μm, and even better to be below 15μm. It can be below 10μm or below 8μm.

[0077] Examples of film systems containing a liquid crystal polarizing layer include linear polarizing layers obtained by coating a composition having liquid crystal properties and anisotropic absorption pigments, or a composition containing anisotropic absorption pigments and polymerizable liquid crystals, onto a substrate film. Examples of substrate films include, for example, films made from resin materials of thermoplastic resins used in the instructions for use to form the first protective film described later. Examples of films containing a liquid crystal polarizing layer include, for example, polarizing layers described in Japanese Patent Application Publication No. 2013-33249, etc.

[0078] The combined thickness of the substrate film and the linear polarizing layer formed in the above manner is preferably smaller. However, if it is too small, the strength will decrease and the processability will tend to deteriorate. Therefore, it is usually below 20 μm, preferably below 5 μm, and even more preferably 0.5 to 3 μm.

[0079] The linear polarizing layer (PVA-based film, film containing a liquid crystal polarizing layer) obtained as described above can be incorporated into a display device in a state where it is separated from one or both sides by an adhesive and is configured as a linear polarizing plate having the first protective film and / or the second protective film described later. The film system containing the liquid crystal polarizing layer can have the aforementioned substrate film configured as the first protective film or the second protective film.

[0080] (First protective film, second protective film) The first and second protective films can be films formed from thermoplastic resins with excellent properties such as transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy, and elongation. Specific examples of thermoplastic resins include cellulose resins such as triacetyl cellulose; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polyether resins; polyether resins; polycarbonate resins; polyamide resins such as nylon or aromatic polyamides; polyimide resins; polyolefin resins such as polyethylene, polypropylene, and ethylene / propylene copolymers; cyclic polyolefin resins having cyclic and norethene structures (also known as norethene-based resins); (meth)acrylic resins; polyaryl ester resins; polystyrene resins; polyvinyl alcohol resins; and mixtures thereof. The resin compositions of the first and second protective films can be the same or different.

[0081] The first protective film may possess anti-reflective, anti-glare, or hard coating properties (hereinafter, a protective film with these properties is sometimes referred to as a "functional protective film"). When the first protective film is not a functional protective film, an anti-reflective layer, an anti-glare layer, or a hard coating layer may be provided on one side of the linear polarizer. Preferably, the surface functional layer is positioned in direct contact with the first protective film. Preferably, the surface functional layer is located on the side of the first protective film opposite to the side of the linear polarizer.

[0082] The first protective film and the second protective film are preferably 3 μm or more, more preferably 5 μm or more, and preferably 50 μm or less, and even more preferably 30 μm or less.

[0083] (Laminator layer 1, laminator layer 2, laminator layer 3, laminator layer 4, laminator layer 5, laminator layer 6) The first, second, third, fourth, fifth, and sixth adhesive layers and the adhesive layer (hereinafter, sometimes collectively referred to as "adhesive layers") are each independently an adhesive layer or a bonding layer.

[0084] When the adhesive layer is an adhesive layer, it is an adhesive layer formed using an adhesive composition. An adhesive composition or its reaction products adhere to the substrate, such as a metal layer, to exhibit adhesion; this is called a pressure-sensitive adhesive. Furthermore, adhesive layers formed using the later-described active energy line curing adhesive composition can have their cross-linking degree or adhesion strength adjusted by irradiating with an active energy line.

[0085] There are no particular limitations on the adhesive composition; adhesives with excellent optical transparency known to be suitable can be used. For example, adhesive compositions containing substrate polymers such as acrylic polymers, urethane polymers, polysiloxane polymers, and polyvinyl ethers can be used. Furthermore, the adhesive composition can be an active energy line curing adhesive composition or a thermosetting adhesive composition. Among these, adhesive compositions using acrylic resins as substrate polymers with excellent transparency, adhesion, re-peelability (reworkability), weather resistance, and heat resistance are suitable. The adhesive layer is preferably composed of a reaction product of an adhesive composition containing (meth)acrylic resin, a crosslinking agent, and a silane compound; other components may also be included.

[0086] The adhesive layer can be formed using an active energy line curing adhesive. This type of adhesive incorporates polyfunctional acrylates and other UV-curable compounds into the aforementioned adhesive composition. After forming the adhesive layer, it is cured by irradiation with ultraviolet light, thereby creating a harder adhesive layer. Active energy line curing adhesives possess the property of curing upon irradiation with energy lines such as ultraviolet light or electron beams. They also possess adhesiveness before energy line irradiation, thus exhibiting strong adhesion to the substrate and the ability to adjust the adhesion force through curing by energy line irradiation.

[0087] There is no particular limitation on the thickness of the adhesive layer, but it is preferably 5μm or more, and can be 10μm or more, 15μm or more, 20μm or more, or 25μm or more. Usually it is less than 300μm, less than 250μm, less than 100μm, or less than 50μm.

[0088] When the adhesive layer is an adhesive layer, the adhesive layer can be formed by curing the curing component in the adhesive composition. The adhesive composition used to form the adhesive layer is an adhesive other than a pressure-sensitive adhesive (adhesive), and examples include: water-based adhesives and active energy line curing adhesives.

[0089] Examples of water-based adhesives include adhesives that dissolve or disperse polyvinyl alcohol resin in water. There are no particular limitations on the drying method when using water-based adhesives; for example, hot air dryers or infrared dryers can be used.

[0090] Examples of active energy line curing adhesives include solvent-free active energy line curing adhesives, which contain curing compounds that are cured by irradiation with active energy lines such as ultraviolet light, visible light, electron beams, and X-rays. Using solvent-free active energy line curing adhesives can improve interlayer adhesion.

[0091] Active energy line curing adhesives exhibit good adhesion and therefore preferably contain either or both of cationic polymerizable curing compounds and free radical polymerizable curing compounds. Active energy line curing adhesives may further contain cationic polymerization initiators, such as photocationic polymerization initiators, or free radical polymerization initiators to initiate the curing reaction of the aforementioned curing compounds.

[0092] Examples of cationicly polymerizable curable compounds include: alicyclic epoxy compounds having epoxy groups bonded to an alicyclic ring; polyfunctional aliphatic epoxy compounds having two or more epoxy groups but no aromatic ring; monofunctional epoxy groups having one epoxy group (except those contained in alicyclic epoxy compounds); polyfunctional aromatic epoxy compounds having two or more epoxy groups and an aromatic ring; oxybutane compounds having one or two or more oxybutane rings within the molecule; and combinations thereof.

[0093] Examples of curing compounds with free radical polymerizability include: (meth)acrylic acid compounds (compounds having one or more (meth)acrylic acid groups in the molecule), other vinyl compounds having free radical polymerizable double bonds, or combinations thereof.

[0094] Active energy line curing adhesives may contain sensitizers such as photosensitizers as needed. The use of sensitizers increases reactivity and further enhances the mechanical strength or adhesive strength of the adhesive layer. Well-known sensitizers may be appropriately used. When preparing the sensitizer, the amount prepared should preferably be in the range of 0.1 to 20 parts by weight relative to 100 parts by weight of the total active energy line curing adhesive.

[0095] Active energy line curing adhesives may contain additives such as ion traps, antioxidants, chain transfer agents, tackifiers, thermoplastic resins, fillers, flow modifiers, plasticizers, defoamers, antistatic agents, leveling agents, and solvents, as needed.

[0096] When using active energy beam curing adhesives, the adhesive coating layer can be hardened by irradiation with active energy beams such as ultraviolet light, visible light, electron beams, or X-rays to form an adhesive layer. Ultraviolet light is preferred as the active energy beam, and the light source can be 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-excited mercury lamp, or a metal halide lamp.

[0097] When the bonding layer is an adhesive layer, the thickness is preferably 0.1 μm or more, and can be 0.5 μm or more, and preferably 10 μm or less, and can be 5 μm or less. [Example]

[0098] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0099] [Determination of Refractive Index] The refractive index of the high refractive index layer was measured at 25°C using a multi-wavelength ABBE refractometer [ATAGO Co., Ltd. "DR-M4"] with a measurement wavelength of 589 nm.

[0100] [Determination of Visual Sensitivity Corrected Single-Unit Transmittance Ty] For the linear polarizing layer, the MD transmittance and TD transmittance in the wavelength range of 380 to 780 nm were measured using a spectrophotometer with an integrating sphere [“V7100” manufactured by Japan Spectrophotometer Co., Ltd.], and the single-cell transmittance at each wavelength was calculated according to the following formula. Single-cell penetration rate (%) = (MD + TD) / 2

[0101] The term "MD transmittance" refers to the transmittance when the direction of polarized light emitted from the Glan-Thompson Prism is parallel to the transmission axis of the linear polarizing layer, and is represented as "MD" in the above formula. Similarly, the term "TD transmittance" refers to the transmittance when the direction of polarized light emitted from the Glan-Thompson Prism is orthogonal to the transmission axis of the linear polarizing layer, and is represented as "TD" in the above formula. For the obtained individual transmittance, visual sensitivity correction is performed using a 2D field of view (C-light source) according to JIS Z 8701:1999 "Methods for displaying colors—XYZ color system and X10Y10Z10 color system" to determine the visual sensitivity-corrected individual transmittance.

[0102] [Determination of in-plane phase difference] The in-plane phase difference value between the first phase difference layer and the first protective film was measured using a phase difference measuring device (KOBRA-WPR manufactured by Oji Measurement & Control Co., Ltd.).

[0103] [Determination of Phase Difference in Thickness Direction] The phase difference value in the thickness direction of the second phase retardation layer was measured using a phase difference measuring device (KOBRA-WPR manufactured by Oji Measurement & Control Co., Ltd.). During the measurement, the incident angle of light on the second phase retardation layer was varied, and the phase difference value was measured with respect to the front of the second phase retardation layer and with the fast axis tilted at 40°. The average refractive index at each wavelength was measured using an ellipsometry M-220 manufactured by Nippon Spectrophotometer Co., Ltd. Furthermore, the thickness of the second phase retardation layer was measured using an Optical NanoGauge C12562-01 manufactured by Hamamatsu Pharmaceuticals Co., Ltd. From the measured front phase difference value, the phase difference value with the fast axis tilted at 40°, the average refractive index, and the thickness of the second phase retardation layer, the 3D refractive index was calculated with reference to the Oji Measurement & Control technical data (https: / / oji-keisoku.co.jp / cms / uploads / kbr_shiryo04.pdf). Based on the obtained 3D refractive index, the phase difference value Rth in the thickness direction of the second phase difference layer is calculated according to the above formula (i).

[0104] [Determination of Stimulus Value Y] The stimulus value Y was determined using a spectrophotometer [CM2600d manufactured by Konica Minolta]. Light from the spectrophotometer was incident on the moth's eye membrane side of the laminate, and the stimulus value Y of the reflected light was measured. Since the reflectivity of the moth's eye membrane is extremely low, the effect of interfacial reflection between the air and the moth's eye membrane on the spectrophotometer's light is negligible. During the measurement, an object with no light reflectivity within 1 m of the light-receiving part of the spectrophotometer in the direction of light travel was identified. To eliminate the influence of external light, the measurement was conducted in a completely dark environment. The results of the spectrophotometer measurement under this environment, without a test sample (laminated body), confirmed that the stimulus value Y was less than 0.1%. Therefore, when measuring the stimulus value Y of the laminate under the above-mentioned measurement environment, a portion of the light detected by the spectrophotometer is absorbed by the polarizer, becoming light reflected only from the high-refractive-index layer. [Example 1]

[0105] (Production of polarizing film (1)) A 20 μm thick polyvinyl alcohol (PVA) resin film (average degree of polymerization approximately 2400, saponification degree ≥ 99.9 moles) was uniaxially stretched longitudinally at a stretch ratio of approximately 4.5 times using a dry stretching method. While maintaining the stretched tension, the film was directly immersed in pure water at 30°C for 60 seconds. Then, while maintaining the tension, it was immersed in an iodine / potassium iodide / water aqueous solution at 28°C for 60 seconds. Next, while maintaining the tension, it was immersed in a potassium iodide / boric acid / water aqueous solution at 64°C for 170 seconds using a potassium iodide / boric acid / water aqueous solution at 15 / 5.5 / 100. Then, while maintaining tension, it was washed with pure water at 10°C for 5 seconds, and then dried in the atmosphere at 80°C for 70 seconds while maintaining tension. Iodine was adsorbed and oriented onto the polyvinyl alcohol resin film to prepare a polarizer (1) (linear polarizing layer) with a thickness of 8μm. The transmittance Ty of the polarizer (1) is 42.2±0.5%.

[0106] (Preparation of the first phase difference layer (1)) A cyclic polyolefin resin film with a hard coating thickness of 25 μm was prepared as the first phase retardation layer (1). The in-plane phase difference value of the first phase retardation layer (1) at a wavelength of 550 nm is 100 nm.

[0107] (Preparation of water-based adhesives) Dissolve 3 parts by mass of carboxyl-modified polyvinyl alcohol [KURARAY Co., Ltd. "KL-318"] in 100 parts by mass of water to obtain a polyvinyl alcohol aqueous solution. Add 1.5 parts by mass of water-soluble polyamide epoxy resin [Taoka Chemical Industry Co., Ltd. "Sumirez Resin 650(30)", solids concentration 30% by mass] (solids concentration 0.45 parts by mass) to the polyvinyl alcohol aqueous solution (100 parts by mass of water) to obtain a water-based adhesive.

[0108] (Fabrication of linear polarizer (1)) A 13 μm thick cyclic polyolefin resin film was prepared as the first protective film. Additionally, a 40 μm thick triacetyl cellulose resin film [Konica Minolta Co., Ltd. "KC4UY", thickness] without surface saponification treatment was prepared as the second protective film.

[0109] On one side of the polarizer (1) obtained above, the first protective film (cyclic polyolefin resin film) prepared above is overlapped with the aqueous adhesive obtained above. On the other side of the polarizer (1), the second protective film (triacetyl cellulose resin film) prepared above is overlapped with pure water. After passing between a pair of bonding rollers, the film is heated and dried at 85°C for 3 minutes, thereby hardening the aqueous adhesive to form an adhesive layer as the third bonding layer, thus producing a linear polarizer (1) having a layer structure of the first protective film / the third bonding layer / polarizer (1) / the second protective film. The phase difference value of the first protective film at a wavelength of 550 nm is 0 nm.

[0110] (Fabrication of a high refractive index layer) On one side of an alkali-free glass plate [CORNING's "EAGLE XG", refractive index 1.50], an ITO (indium tin oxide) film, which is a mixture of indium oxide and tin oxide, was deposited by vacuum evaporation to form an ITO layer with a thickness of 100 μm, thus obtaining a high refractive index layer of the laminated structure of the alkali-free glass plate and the ITO layer. The refractive index of this high refractive index layer was measured from the ITO layer side, and the result was 2.00.

[0111] (Fabrication of laminate (1)) Next, the second protective film is peeled off from the linear polarizer (1). On the exposed polarizer (1) side, a moth-eye film (GEOMATECH g.moth) is laminated through a fourth bonding layer (25 μm thick acrylic adhesive layer). On the first protective film side of the linear polarizer (1), the second bonding layer (5 μm thick acrylic adhesive layer), the first phase retardation layer (1), the first bonding layer (25 μm thick acrylic adhesive layer), an alkali-free glass plate (EAGLE XG, refractive index 1.50) with a refractive index of 1.50, and a high refractive index layer (ITO layer) with a refractive index of 2.00, and a black acrylic plate are laminated to form a laminate (1). The laminate (1) is laminated with the high refractive index layer on the black acrylic plate side. The high refractive index layer and the black acrylic plate are filled with ethanol droplets before lamination to remove the air layer. The first phase retardation layer (1) is laminated with the hard coating side becoming the high refractive index layer side. In the laminate (1), the slow axis of the first phase retardation layer (1) and the absorption axis of the polarizer (1) of the linear polarizer (1) form an angle of 45°. The resulting laminate (1) has the following layer structure: black acrylic plate / ethanol / high refractive index layer / first bonding layer / first phase retardation layer (1) / second bonding layer / first protective film / third bonding layer / polarizer (1) / fourth bonding layer / moth eye membrane. The results of measuring the stimulus value Y of the laminate (1) are presented in Table 1. The moth eye membrane is used to evaluate the laminate (1) without ignoring the influence of the interface reflection between the fourth bonding layer and the air layer. In the actual display device, the display unit is arranged on the side opposite to the polarizer (1) of the fourth bonding layer. [Example 2]

[0112] (Preparation of the first phase difference layer (2)) A 50 μm thick cyclic polyolefin resin film was prepared as the first phase retardation layer (2). The in-plane phase difference value of the first phase retardation layer (2) at a wavelength of 550 nm was 141 nm.

[0113] (Fabrication of laminate (2)) Except for replacing the first phase retardation layer (1) with the first phase retardation layer (2), the laminate (2) was obtained in the same order as in Example 1. The layer structure of the obtained laminate (2) is black acrylic plate / ethanol / high refractive index layer / first bonding layer / first phase retardation layer (2) / second bonding layer / first protective film / third bonding layer / polarizer (1) / fourth bonding layer / moth eye film. The results of measuring the stimulation value Y of the laminate (2) are presented in Table 1. [Example 3]

[0114] (Preparation of components for horizontally oriented film formation) Five parts by mass of a photo-oriented polymer with the following structure (described in Japanese Patent Application Publication No. 2013-33249) and 95 parts by mass of cyclopentanone (solvent) were mixed and stirred at 80°C for 1 hour to obtain a composition for forming a horizontally oriented film. • Photooriented polymer (5 parts by weight): Solvent (95 parts by weight): Cyclopentanone

[0115] (Modulation of polymeric liquid crystal composition (A1) used for forming the first phase difference layer (3)) A polymerizable liquid crystal compound (X1) and a polymerizable liquid crystal compound (X2) were mixed at a mass ratio of 90:10 to obtain a mixture. 0.1 parts of a leveling agent "BYK-361N" (manufactured by BM Chemie) and 6 parts of 2-dimethylamino-2-phenylmethyl-1-(4-morphofolinylphenyl)butane-1-one (manufactured by BASF JAPAN Co., Ltd., "IRGACURE (registered trademark) 369 (Irg 369)") as a photopolymerization initiator were added relative to 100 parts of the obtained mixture. Furthermore, N-methyl-2-pyrrolidone (NMP) was added to a solids concentration of 13%. The mixture was stirred at 80°C for 1 hour to obtain a polymerizable liquid crystal composition (A1) for forming the first phase difference layer (3).

[0116] Polymerizable liquid crystal compound (X1):

[0117] Polymerizable liquid crystal compound (X2):

[0118] (Fabrication of the first phase difference layer (3)) After corona treatment on a COP (cyclic olefin resin) film (ZF-14-50) manufactured by ZEON Corporation of Japan, the obtained composition for forming a horizontally oriented film was coated using a bar coater, dried at 80°C for 1 minute, and then exposed to polarized UV light at a wavelength of 313 nm with a cumulative light intensity of 100 mJ / cm² using a polarized UV irradiation device (SPOT CURE SP-9; manufactured by USHIO Electric Co., Ltd.) to obtain a horizontally oriented film. The thickness of the obtained horizontally oriented film was measured using an ellipsometry and found to be 200 nm.

[0119] Subsequently, the polymeric liquid crystal composition (A1) obtained above was coated on the planar alignment film using a rod coater. After heating at 120°C for 60 seconds, a horizontally aligned liquid crystal layer (a hardened layer of the polymeric liquid crystal compound) was formed by irradiating the surface coated with polymeric liquid crystal composition (A1) with ultraviolet light (cumulative light intensity at a wavelength of 365nm under nitrogen environment: 500mJ / cm2) to form a layered structure (COP film / horizontal alignment film / horizontal alignment liquid crystal layer). After confirming that there was no phase difference in the COP film, the in-plane phase difference values ​​Re(450) and Re(550) of the layered structure (A1) at wavelengths of 450nm and 550nm were measured as the in-plane phase difference values ​​Re(450) and Re(550) of the first phase difference layer (3). The measured value of Re(550) was 139nm. The calculated Re(450) / Re(550) is 0.87, confirming that the stacked system exhibits inverse wavelength dispersion.

[0120] The COP film of the stacked structure (A1) is peeled off, and the horizontally aligned film / horizontally aligned liquid crystal layer is used as the first phase difference layer (3).

[0121] (Fabrication of laminate (3)) Except for replacing the first phase retardation layer (1) with the first phase retardation layer (3), the laminate (3) was obtained in the same order as in Example 1. The first phase retardation layer (3) was laminated with the horizontally oriented film side becoming the high refractive index layer side. The layer structure of the resulting laminate (3) is: black acrylic plate / ethanol / high refractive index layer / first bonding layer / first phase retardation layer (3) / second bonding layer / first protective film / third bonding layer / polarizer (1) / fourth bonding layer / moth eye film. The results of measuring the stimulation value Y of the laminate (3) are presented in Table 1. [Example 4]

[0122] (Preparation of components for vertically oriented film formation) The silane coupling agent "KBE-9103" (manufactured by Shin-Etsu Chemical Co., Ltd.) was dissolved in a mixed solvent of ethanol and water in a 9:1 (weight ratio) ratio to obtain a vertically oriented film forming composition with a solid content of 1%.

[0123] (Modulation of polymeric liquid crystal composition (A2) used for forming the second phase difference layer (1)) 0.1 parts of Paliocolor LC242 (a registered trademark of BASF), a polymerizable liquid crystal compound, and 3 parts of IRGACURE 369, a polymerization initiator, were added to 100 parts of the compound. Cyclopentanone was added to bring the solids concentration to 13%, thus obtaining the polymerizable liquid crystal composition (A2).

[0124] (Fabrication of the second phase difference layer (1)) After corona treatment on a COP (cyclic olefin resin) membrane (ZF-14-50) manufactured by ZEON Corporation of Japan, a vertically oriented film-forming composition was coated using a bar coater and dried at 120°C for 1 minute to obtain a vertically oriented film. The thickness of the obtained vertically oriented film was measured using an ellipsometry and found to be 100 nm.

[0125] Subsequently, the polymeric liquid crystal composition (A2) obtained above was coated onto the vertically aligned film using a rod coater. After drying at 120°C for 1 minute, a vertically aligned liquid crystal layer (a hardened layer of the polymeric liquid crystal compound) was formed by irradiating the coated polymeric liquid crystal composition (A2) with ultraviolet light (cumulative light intensity at a wavelength of 365 nm under nitrogen environment: 500 mJ / cm2) from the side coated with ultraviolet light (UNICURE VB-15201BY-A, manufactured by USHIO Electric Co., Ltd.). A laminated structure (A2) with a layer structure of COP film / vertically aligned film / vertically aligned liquid crystal layer was obtained. After confirming that there was no phase difference in the COP film, the phase difference value Rth(550) in the thickness direction of the laminated structure (A2) at a wavelength of 550 nm was measured as the phase difference value Rth(550) in the thickness direction of the second phase difference layer (1). The result Rth(550) was -70 nm.

[0126] The COP film and vertically aligned film of the stacked structure (A2) are peeled off, and the vertically aligned liquid crystal layer is used as the second phase difference layer (1).

[0127] (Fabrication of laminate (4)) The first phase difference layer (3) and the second phase difference layer (1) were bonded together using a UV-curable adhesive in the same order as in Example 3. The UV-curable adhesive was then cured to form an adhesive layer (1 μm thick) as the sixth bonding layer, and a phase difference stack of the second phase difference layer (1) / the sixth bonding layer / the first phase difference layer (3) was formed.

[0128] Except for replacing the first phase difference layer (1) with a phase difference stack, the stack (4) was obtained in the same order as in Example 1. The phase difference stack system was stacked with the second phase difference layer (1) side becoming the high refractive index layer side. The layer structure of the obtained stack (4) is black acrylic plate / ethanol / high refractive index layer / first bonding layer / second phase difference layer (1) / sixth bonding layer / first phase difference layer (3) / second bonding layer / first protective film / third bonding layer / polarizer (1) / fourth bonding layer / moth eye film. The results of measuring the stimulation value Y of the stack (4) are presented in Table 1.

[0129] [Table 1] [Example 5]

[0130] (Production of polarizing film (2)) A 20 μm thick polyvinyl alcohol (PVA) resin film (average degree of polymerization approximately 2400, degree of saponification ≥ 99.9 moles) was uniaxially stretched longitudinally at a stretch ratio of approximately 4.5 times using a dry stretching method. While maintaining the stretched tension, the film was directly immersed in pure water at 30°C for 60 seconds. Then, while maintaining the tension, it was immersed in an iodine / potassium iodide / water aqueous solution at 28°C for 60 seconds. Next, while maintaining the tension, it was immersed in a potassium iodide / boric acid / water aqueous solution at 64°C for 45 seconds. Then, while maintaining the tension, it was washed with pure water at 10°C for 5 seconds. Next, while maintaining the tension, it was dried in the atmosphere at 80°C for 75 seconds. Iodine was adsorbed and oriented onto the polyvinyl alcohol resin film to create a polarizer (2) (linear polarizing layer) with a thickness of 8 μm. The transmittance Ty of the polarizer (2) was 46.0 ± 0.5%.

[0131] (Fabrication of laminate (5)) Except for replacing polarizer (1) with polarizer (2), the laminate (5) was obtained in the same order as in Example 1. The layer structure of the obtained laminate (5) is black acrylic plate / ethanol / high refractive index layer / first bonding layer / first phase difference layer (1) / second bonding layer / first protective film / third bonding layer / polarizer (2) / fourth bonding layer / moth eye membrane. The results of measuring the stimulation value Y of the laminate (5) are presented in Table 2. [Example 6]

[0132] Except for replacing polarizer (1) with polarizer (2), the laminate (6) was obtained in the same order as in Example 2. The layer structure of the obtained laminate (6) is black acrylic plate / ethanol / high refractive index layer / first bonding layer / first phase difference layer (2) / second bonding layer / first protective film / third bonding layer / polarizer (2) / fourth bonding layer / moth eye membrane. The results of measuring the stimulation value Y of the laminate (6) are presented in Table 2. [Example 7]

[0133] Except for replacing polarizer (1) with polarizer (2), the laminate (7) was obtained in the same order as in Example 3. The layer structure of the obtained laminate (7) is black acrylic plate / ethanol / high refractive index layer / first bonding layer / first phase difference layer (3) / second bonding layer / first protective film / third bonding layer / polarizer (2) / fourth bonding layer / moth eye membrane. The results of measuring the stimulation value Y of the laminate (7) are presented in Table 2. [Example 8]

[0134] Except for replacing polarizer (1) with polarizer (2), the laminate (8) was obtained in the same order as in Example 4. The layer structure of the obtained laminate (8) is: black acrylic plate / ethanol / high refractive index layer / first bonding layer / second phase retardation layer (1) / sixth bonding layer / first phase retardation layer (3) / second bonding layer / first protective film / third bonding layer / polarizer (2) / fourth bonding layer / moth eye membrane. The results of measuring the stimulation value Y of the laminate (8) are presented in Table 2. [Comparative Example 1]

[0135] Except for the absence of the first phase difference layer (1) and the second bonding layer, and the deposition of a high refractive index layer on the first protective film with a first adhesive layer in between, the laminate (9) was obtained in the same order as in Example 5. The layer structure of the obtained laminate (9) is: black acrylic sheet / ethanol / high refractive index layer / first bonding layer / first protective film / third bonding layer / polarizer (2) / fourth bonding layer / moth eye film. The results of measuring the stimulation value Y of the laminate (9) are presented in Table 2.

[0136] [Table 2]

[0137] From the results shown in Tables 1 and 2, it can be seen that if the in-plane phase difference of the first phase difference layer is in the range of 80nm to 170nm, the stimulus value Y decreases, and the reflected light incident on the light-receiving element of the display unit can be reduced. Furthermore, it can be seen that even when the transmittance Ty of the polarizer correction monomer contained in the laminate is large, the stimulus value Y can still be reduced, and the reflected light incident on the light-receiving element of the display unit can be reduced.

[0138] 1~4: Display device 11: Linear polarizing layer 12: First protective film 13: Third phase difference layer 21: First bonding layer 22: Second bonding layer 23: Third bonding layer 24: Fourth bonding layer 25: Fifth bonding layer 26: 6th bonding layer 31: First phase difference layer 32: Second phase difference layer 40: Display Unit 41: Display element 42: Light sensor 45: High Refractive Index Layer 51~54: Optical laminates

Claims

1. A display device having, sequentially from the recognition side, a high refractive index layer, a first retardation layer, a linear polarizing layer, and a display unit, wherein the refractive index of the high refractive index layer is 1.60 or higher, the display unit has a display element and a light sensor, and the first retardation layer and the linear polarizing layer are laminated to cover the display element and the light sensor.

2. The display device as described in claim 1, wherein, In the plan view, the aforementioned first phase difference layer covers the entire surface of the identification side of the aforementioned linear polarizing layer.

3. The display device as described in claim 1 or 2, wherein, The aforementioned linear polarizing layer has a visual sensitivity correction unit transmittance of over 42%.

4. The display device as described in claim 1 or 2, wherein, The angle between the slow axis of the aforementioned first phase difference layer and the absorption axis of the aforementioned linear polarizing layer is between 10° and 80°.

5. The display device as described in claim 1 or 2, wherein, The aforementioned first phase difference layer has an in-plane phase difference value of 80nm or more and 170nm or less at a wavelength of 550nm.

6. The display device as described in claim 5, wherein, The aforementioned first phase difference layer has inverse wavelength dispersion.

7. The display device as claimed in claim 5, further comprising a second phase difference layer between the aforementioned high refractive index layer and the aforementioned linear polarizing layer, wherein the aforementioned second phase difference layer is laminated in such a manner as to cover the aforementioned display element and the aforementioned photosensitive sensor, and wherein the phase difference value of the aforementioned second phase difference layer in the thickness direction at a wavelength of 550 nm is greater than or equal to -140 nm and less than or equal to -20 nm.

8. The display device as described in claim 1 or 2, wherein, The stimulus value Y of the reflected light when the light emitted from the aforementioned display element is reflected by the aforementioned high refractive index layer is 3.45% or more and 4.54% or less.

9. The display device as described in claim 1 or 2, wherein, The aforementioned light sensor can detect light with wavelengths between 320nm and 4000nm.

10. The display device as described in claim 1 or 2, wherein, The emitted light from the aforementioned display element has a wavelength of 320nm or higher and 4000nm or lower.

11. The display device as claimed in claim 1 or 2, further comprising a third phase difference layer between the aforementioned linear polarizing layer and the aforementioned display unit.

12. An optical stack having, in sequence, a high refractive index layer, a first retardation layer and a linear polarizing layer, wherein the refractive index of the aforementioned high refractive index layer is 1.60 or higher.

13. The optical laminate as described in claim 12, wherein, In the plan view, the aforementioned first phase difference layer covers the entire surface of the identification side of the aforementioned linear polarizing layer.

14. The optical laminate as described in claim 12 or 13, wherein, The aforementioned linear polarizing layer has a visual sensitivity correction unit transmittance of over 42%.

15. The optical laminate as described in claim 12 or 13, wherein, The angle between the slow axis of the aforementioned first phase difference layer and the absorption axis of the aforementioned linear polarizing layer is between 10° and 80°.

16. The optical laminate as described in claim 12 or 13, wherein, The aforementioned first phase difference layer has an in-plane phase difference value of 80nm or more and 170nm or less at a wavelength of 550nm.

17. The optical laminate as described in claim 12 or 13, wherein, The aforementioned first phase difference layer has inverse wavelength dispersion.

18. The optical stack as described in claim 12 or 13, further comprising a second phase difference layer between the aforementioned high refractive index layer and the aforementioned linear polarizing layer, wherein the phase difference of the aforementioned second phase difference layer in the thickness direction at a wavelength of 550 nm is greater than -140 nm and less than -20 nm.

19. The optical laminate as described in claim 12 or 13, wherein, On the opposite side of the aforementioned linear polarizing layer and the aforementioned first phase difference layer, there is a third phase difference layer.