WO2022270402A1

WO2022270402A1 - Display device

Info

Publication number: WO2022270402A1
Application number: PCT/JP2022/024116
Authority: WO
Inventors: 瑛高月
Original assignee: 住友化学株式会社
Priority date: 2021-06-23
Filing date: 2022-06-16
Publication date: 2022-12-29
Also published as: TW202307486A; KR20240024067A

Abstract

[Problem] To provide a display device (1) that is capable of suppressing the incidence of reflected light, which has been reflected by a high refractive index layer (45), on a light-receiving sensor (42) and to further provide an optical laminate (51) that is for use in the display device (1). [Solution] A display device (1) according to the present invention has a high refractive index layer (42), a first retardation layer (31), a linear polarization layer (11), and a display unit (40) in this order from the viewing side. The high refractive index layer (42) has a refractive index of 1.60 or more. The display unit (40) has a display element (41) and a light-receiving sensor (42). The first retardation layer (31) and the linear polarization layer (11) are laminated so as to cover the display element (41) and the light-receiving sensor (42). [Selected drawing] FIG. 1

Description

Display device

The present invention relates to a display device, and further to an optical layered body used therein.

A polarizing plate including a linear polarizing layer can be used as a polarized light supply element or a polarized light detection element in a display device such as a liquid crystal display device or an organic electroluminescence (EL) display device, or can be used as an external light reflected by the display device. It is widely used as a device for suppressing radiation to the Display devices equipped with polarizing plates are also used in mobile devices such as notebook personal computers, smartphones, and tablet terminals. Patent Literature 1 describes that from the viewpoint of design and expansion of the display area on the display surface of a mobile device such as a smart phone, for example, in a plan view, a non-display area is provided by notching the outer edge of the display area in a concave shape. there is

A display element and a polarizing plate are usually not arranged in the non-display area provided in the concave shape. Therefore, by arranging a camera lens and various sensors such as a light receiving sensor in the non-display area, it is possible to prevent the performance of the camera and the sensitivity of the sensor from being adversely affected.

JP 2019-219528 A

In order to further expand the display area on the display surface, it is required to reduce the non-display area. In this case, it is conceivable to dispose various sensors such as a light receiving sensor in the display area provided with the display element and the polarizing plate. When the light-receiving sensor is arranged in the display area, the light emitted from the display element is reflected by the high refractive index layer arranged on the viewing side of the polarizing plate and easily enters the light-receiving sensor. The reflected light incident on the light-receiving sensor is likely to cause malfunction of the light-receiving sensor.

The present invention provides a display device capable of suppressing the incidence of light reflected by the high refractive index layer from entering a light receiving sensor even when the high refractive index layer is provided on the viewing side, and an optical laminate used therein. With the goal.

The present invention provides the following display device.
[1] A display device having a high refractive index layer, a first retardation layer, a linear polarizing layer, and a display unit in this order from the viewing side,
The refractive index of the high refractive index layer is 1.60 or more,
The display unit has a display element and a light receiving sensor,
The display device, wherein the first retardation layer and the linear polarization layer are laminated so as to cover the display element and the light receiving sensor.
[2] The display device according to [1], wherein the first retardation layer covers the entire surface of the linear polarizing layer on the viewing side in plan view.
[3] The display device according to [1] or [2], wherein the luminosity correction single transmittance of the linearly polarizing layer is 42% or more.
[4] The display according to any one of [1] to [3], 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. Device.
[5] The display device according to any one of [1] to [4], 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.
[6] The display device according to [5], wherein the first retardation layer has reverse wavelength dispersion.
[7] further comprising a second retardation layer between the high refractive index layer and the linear polarizing layer;
The second retardation layer is laminated so as to cover the display element and the light receiving sensor,
The display device according to [5] or [6], wherein 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.
[8] The stimulation value Y of the reflected light when the light emitted from the display element is reflected by the high refractive index layer is 3.45% or more and 4.54% or less of [1] to [7]. The display device according to any one of the above.
[9] The display device according to any one of [1] to [8], wherein the light receiving sensor can detect light with a wavelength of 320 nm or more and 4000 nm or less.
[10] The display device according to any one of [1] to [9], wherein the light emitted from the 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 comprising a third retardation layer between the linear polarizing layer and the display unit.

The present invention provides the following optical layered body.
[12] An optical laminate having a high refractive index layer, a first retardation layer and a linear polarizing layer in this order,
The optical laminate, wherein the high refractive index layer has a refractive index of 1.60 or more.
[13] The optical layered body according to [12], wherein the first retardation layer covers the entire surface of the linear polarizing layer on the viewing side in plan view.
[14] The optical laminate according to [12] or [13], wherein the linear polarizing layer has a luminosity correction single transmittance of 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 reverse wavelength dispersion.
[18] further comprising a second retardation layer between the high refractive index layer and the linear polarizing layer;
The optical laminate according to [12] or [13], wherein 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 layered body according to [12] or [13], further comprising a third retardation layer on the opposite side of the linear polarizing layer to the first retardation layer.

According to the display device of the present invention, it is possible to suppress the reflected light reflected by the high refractive index layer from entering the light receiving sensor. Further, according to the optical layered body of the present invention, the display device of the present invention can be provided.

1 is a schematic cross-sectional view schematically showing a display device according to an embodiment of the invention; FIG. FIG. 3 is a schematic cross-sectional view schematically showing a display device according to another embodiment of the invention; FIG. 4 is a schematic cross-sectional view schematically showing a display device according to still another embodiment of the invention; FIG. 4 is a schematic cross-sectional view schematically showing a display device according to still another embodiment of the invention;

Preferred embodiments of the display device and the optical layered body will be described below with reference to the drawings. In each drawing, the same reference numerals are assigned to the same members as those previously described, and the description thereof will be omitted.

[Embodiment 1]
(Display device and optical laminate)
1 and 2 are schematic cross-sectional views schematically showing a display device according to an embodiment of the invention. 1 and 2, the upper side is the viewing side. As shown in FIGS. 1 and 2, in the display devices 1 and 2 of the present embodiment, the high refractive index layer 45, the first retardation layer 31, the linear polarizing layer 11, and the display unit 40 are arranged in this order from the viewing side. have. Among them, 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 more, preferably 1.75 or more, more preferably 1.80 or more, usually 2.70 or less, preferably 2.40 or less. , more preferably 2.30 or less, and still more preferably 2.10 or less. The refractive index of the high refractive index layer 45 can be measured by the method described in Examples below.

The display unit 40 has a display element 41 and a light receiving sensor 42 . As shown in FIGS. 1 and 2, the display unit 40 may have a structure in which a light receiving sensor 42 is stacked on the viewing side of the display element 41, and the light receiving sensor 42 is stacked on the side opposite to the viewing side of the display element 41. The sensor 42 may have a laminated structure. Alternatively, the light-receiving sensor 42 may be fitted in a through hole or recess provided in the display element 41 . In the display unit 40, since the area of the display element 41 can be used as the display area of the display devices 1 and 2, from the viewpoint of enlarging the display area, in the plan view of the display unit 40, the light receiving sensor 42 is surrounded. It is preferable that the area of the display element 41 exists in the area of the display element 41 .

In the display devices 1 and 2, the first retardation layer 31 and the linear polarization layer 11 are laminated so as to cover the display element 41 and the light receiving sensor . The first retardation layer 31 and the linear polarizing layer 11 are laminated so as to cover the entire visible-side surface of the display unit 40, that is, to cover the entire visible-side surfaces of the display element 41 and the light receiving sensor 42. is preferred. By providing the linear polarizing layer 11 as described above, the area of the display element 41 around the light receiving sensor 42 is covered with the linear polarizing layer 11 in plan view, so that the display areas of the display devices 1 and 2 are expanded. easier. As long as the first retardation layer 31 is laminated so as to cover the display element 41 and the light receiving sensor 42, it may cover the entire linear polarization layer 11 in a plan view, or may cover a part thereof. The planar view shape of the first retardation layer 31 may be the same as or different from the planar view shape of the linear polarizing layer 11 .

In the display devices 1 and 2, image display is performed by light emitted from the display element 41. Part of the light emitted from the display element 41 may be reflected by the high refractive index layer 45 and enter the light receiving sensor 42 as indicated by the arrow in FIG. In particular, when the area of the display element 41 is arranged around the light receiving sensor 42, such as when the area of the light receiving sensor 42 and the area of the display element 41 are adjacent to each other in the plan view of the display unit 40, for example. , the reflected light reflected by the high refractive index layer 45 is likely to enter the light receiving sensor 42 . When the reflected light is incident on the light receiving sensor 42, malfunction of the light receiving sensor 42 is likely to occur. In the display devices 1 and 2 of the present embodiment, the first retardation layer 31 is laminated on the visible side of the linear polarization layer 11 covering the display element 41 and the light receiving sensor 42 . The reflected light reflected by the high refractive index layer 45 is incident on the first retardation layer 31 and changes its phase by passing through the first retardation layer 31 . Therefore, at least part of the reflected light that has passed through the first retardation layer 31 is likely to be absorbed by the linear polarizing layer 11 . As a result, the light amount of the reflected light incident on the light receiving sensor 42 can be reduced, so that malfunction of the light receiving sensor 42 can be suppressed.

The visibility correction single transmittance of the linear polarizing layer 11 is preferably 42% or more, more preferably 43% or more, and may be 45% or more. When the luminosity correction single transmittance of the linear polarizing layer 11 increases, the light amount of the reflected light that passes through the linear polarizing layer 11 increases, so that the light receiving sensor 42 is likely to malfunction. According to the display devices 1 and 2 of the present embodiment, even when the linear polarizing layer 11 having a large luminosity correction single transmittance is used, the light amount of the reflected light incident on the light receiving sensor 42 is suppressed, and the light receiving sensor 42 malfunction can be suppressed. The luminosity correction single transmittance of the linear polarizing layer 11 can be measured by the method described in Examples below.

Although the first retardation layer 31 may have a retardation, it preferably has a retardation in which the in-plane retardation value Re(550) at a wavelength of 550 nm is 80 nm or more and 170 nm or less. The in-plane retardation value Re (550) of the first retardation layer 31 is more preferably 100 nm or more, particularly preferably 130 nm or more, may be 135 nm or more, and is 160 nm or less. is more preferably 150 nm or less. The in-plane retardation value Re(550) of the first retardation layer 31 can be measured by the method described in Examples below.

When the first retardation layer 31 has an in-plane retardation value Re (550) within the above range, the light emitted from the display element 41 in the display devices 1 and 2 is elliptically polarized when passing through the first retardation layer 31. converted. The reflected light (elliptically polarized light) reflected by the high refractive index layer 45 is converted into linearly polarized light by passing through the first retardation layer 31 . As a result, the reflected light that has passed through the first retardation layer 31 is more likely to be absorbed by the linear polarization layer 11, so that the amount of reflected light that enters the light receiving sensor 42 can be further suppressed.

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

The first retardation layer 31 whose in-plane retardation value Re(550) is within the above range preferably has reverse wavelength dispersion. As a result, the wavelength range of the reflected light absorbed by the linear polarizing layer 11 is widened, so that the amount of reflected light of various wavelengths incident on the light receiving sensor 42 can be suppressed.

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

In the display devices 1 and 2 in which the stimulus value Y of the emitted light is within the above range, it is easy to suppress the amount of reflected light incident on the light receiving sensor 42 . If the stimulus value Y of the emitted light is smaller than the above range, it is considered that the refractive index of the high refractive index layer 45 is small, or the luminosity correction single transmittance of the linear polarizing layer 11 is small. Therefore, in a display device in which the stimulus value Y of emitted light is smaller than the above range, the amount of reflected light incident on the light receiving sensor 42 is small, and malfunction of the light receiving sensor 42 is unlikely to occur. In addition, in a display device in which the stimulus value Y of emitted light is larger than the above range, the amount of reflected light incident on the light receiving sensor 42 is large, and malfunction of the light receiving sensor 42 is likely to occur.

(Layer structure of display device and optical laminate)
Hereinafter, layers that the display devices 1 and 2 and the

optical laminates

51 and 52 may have in addition to the layers described above will be described.

The display devices 1 and 2 and the

optical laminates

51 and 52 may have the first bonding layer 21 between the high refractive index layer 45 and the first retardation layer 31 as shown in FIGS. preferable. The first bonding layer 21 may be in direct contact with the high refractive index layer 45 and the first retardation layer 31 .

The display devices 1 and 2 and the

optical laminates

51 and 52 may have one or more second refractive index layers (not shown) apart from the high refractive index layer 45 described above. The refractive index of the second refractive index layer can be within the above refractive index range described for the high refractive index layer 45 . The second refractive index layer may be provided on the viewer side of the high refractive index layer 45 or may be provided between the high refractive index layer 45 and the first retardation layer 31 . In this case, the display devices 1 and 2 and the

optical laminates

51 and 52 have a lamination layer (adhesive layer or adhesive layer described later) between the high refractive index layer 45 and the second refractive index layer. Alternatively, the lamination layer may be in direct contact with the high refractive index layer 45 and the second refractive index layer. When the display devices 1 and 2 and the

optical laminates

51 and 52 have the second refractive index layer between the high refractive index layer 45 and the first retardation layer 31, the first bonding layer 21 is the first It may be in direct contact with the retardation layer 31 and the second refractive index layer.

The display devices 1 and 2 and the

optical laminates

51 and 52 preferably have the second bonding layer 22 between the first retardation layer 31 and the linear polarizing layer 11 . The second bonding layer 22 may be in direct contact with the first retardation layer 31 and the linear polarizing layer 11 .

The display devices 1 and 2 and the

optical laminates

51 and 52 have a first protective film 12 between the first retardation layer 31 and the linear polarizing layer 11, as shown in FIGS. good too. The first protective film 12 may be a layer for protecting the viewing side surface of the linear polarizing layer 11, and 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 .

When the display devices 1 and 2 and the

optical laminates

51 and 52 have the first protective film 12, the display devices 1 and 2 and the

optical laminates

51 and 52 are such that the first protective film 12 and the linear polarizing layer 11 are in direct contact. However, it is preferable to have the third bonding layer 23 between the first protective film 12 and the linear polarizing layer 11 . The third bonding layer 23 may constitute a linear polarizing plate, and is preferably in direct contact with the first protective film 12 and the linear polarizing layer 11 .

The 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 opposite to the first retardation layer 31 side of the linear polarizing layer 11). good. The linear polarizing layer 11 and the display unit 40 may be in direct contact with the fourth bonding layer 24 as shown in FIG. As shown in FIGS. 1 and 2, the fourth bonding layer 24 may be included in the

optical laminates

51 and 52 .

In the display devices 1 and 2 and the

optical laminates

51 and 52, a second protective film ( (not shown). The second protective film may be a layer for protecting the surface of the linear polarizing layer 11 opposite to the viewing side, and the second protective film and the linear polarizing layer 11 may constitute a linear polarizing plate. good. When the display devices 1 and 2 and the

optical laminates

51 and 52 have the second protective film, the second protective film and the linear polarizing layer 11 may be in direct contact with each other. A lamination layer (a pressure-sensitive adhesive layer or an adhesive layer to be described later) may be provided therebetween. This bonding layer may constitute a linear polarizing plate, and is preferably in direct contact with the second protective film and the linear polarizing layer 11 . In this case, the fourth bonding layer 24 may be provided between the second protective film and the display unit 40 or may be in direct contact with the second protective film and the display unit 40 .

In the display device 2 and the optical laminate 52, as shown in FIG. 2, a third It may have a retardation layer 13 . In this case, the display device 2 and the optical laminate 52 may have a fifth bonding layer 25 between the linear polarizing layer 11 and the third retardation layer 13, and The retardation layer 13 may be in direct contact with the fifth bonding layer 25 . When the display device 2 and the optical laminate 52 have a second protective film, the fifth bonding layer 25 is provided between the second protective film and the third retardation layer 13, and the second protective film and the third It may be in direct contact with the retardation layer 13 . In the display device 2 having the third retardation layer 13, the fourth bonding layer 24 may be provided between the third retardation layer 13 and the display unit 40, the third retardation layer 13 and the display unit 40 may be in direct contact. In the optical laminate 52 having the third retardation layer 13 , the fourth bonding layer 25 may be in direct contact with the third retardation layer 13 . The linearly polarizing layer 11 and the third retardation layer 13 preferably form a circularly polarizing plate, and the third retardation layer 13 is preferably a λ/4 retardation layer, and more preferably has reverse wavelength dispersion properties. It is a λ/4 retardation layer.

In the display device 2 and the optical laminate 52, between the linear polarizing layer 11 and the display unit 40 (on the opposite side of the linear polarizing layer 11 to the first retardation layer 31 side), may have one or more fourth retardation layers (not shown). The fourth retardation layer may be provided between the linear polarization layer 11 and the third retardation layer 13, and between the third retardation layer 13 and the display unit 40 (the linear polarization of the third retardation layer 13 It may be provided on the side opposite to the layer 11 side). In this case, between the third retardation layer 13 and the fourth retardation layer may have a bonding layer (adhesive layer or adhesive layer described later), the bonding layer is the third retardation It may be in direct contact with the layer 13 and the fourth retardation layer. When the display device 2 and the optical laminate 52 have a fourth retardation layer between the linear polarization layer 11 and the third retardation layer 13, the fifth bonding layer 25 is the linear polarization layer 11 and the fourth retardation layer may be in direct contact with When the display device 2 has a fourth retardation layer between the third retardation layer 13 and the display unit 40, the fourth bonding layer 24 may be in direct contact with the fourth retardation layer and the display unit 40. . When the optical laminate 52 has a third retardation layer on the side opposite to the linear polarization layer 11 side of the third retardation layer 13, the fourth retardation layer may be in direct contact with the fourth bonding layer. . The linearly polarizing layer 11, the third retardation layer 13, and the fourth retardation layer preferably form a circularly polarizing plate. The fourth retardation layer constituting the circularly polarizing plate is preferably a λ/2 retardation layer or a positive C layer.

[Embodiment 2]
3 and 4 are schematic cross-sectional views schematically showing display devices according to other embodiments of the present invention. 3 and 4, the upper side is the viewing side. The

display devices

3 and 4 and the

optical laminates

53 and 54 of the present embodiment have the second retardation layer 32 between the high refractive index layer 45 and the linear polarizing layer 11. Since it is different from the display devices 1 and 2 and the

optical laminates

51 and 52 described in 1., this point will be described below.

In the

display devices

3 and 4, the second retardation layer 32 is laminated so as to cover the display element 41 and the light receiving sensor 42. The second retardation layer 32 is preferably laminated so as to cover the entire visible-side surface of the display unit 40 , that is, to cover the entire visible-side surfaces of the display element 41 and the light receiving sensor 42 .

The

display devices

3 and 4 and the

optical laminates

53 and 54 shown in FIGS. 3 and 4 have the second retardation layer 32 between the high refractive index layer 45 and the first retardation layer 31 . The second retardation layer 32 preferably covers the entire first retardation layer 31 in plan view, and the planar view shape of the second retardation layer 32 is the planar view shape of the first retardation layer 31. More preferably, they are the same.

Although the second retardation layer 32 may have a retardation, it preferably has a retardation in which the thickness direction retardation value Rth(550) at a wavelength of 550 nm is -140 nm or more and -20 nm or less. The thickness direction retardation value Rth (550) of the second retardation layer 32 may be greater than −140 nm, may be −120 nm or more, may be −100 nm or more, or may be −90 nm or more. It may be less than -20 nm, may be -30 or less, may be -40 or less, or may be -50 or less.

The thickness direction retardation value Rth (550) of the second retardation layer 32 is a value calculated based on the formula (i).
Rth(550)=[{(nx+ny)/2}-nz]×d(i)
[In the formula (i),
nx is the principal refractive index at a wavelength of 550 nm in the plane of the second retardation layer 32,
ny is the refractive index at a wavelength of 550 nm in the same plane as nx and in a direction orthogonal to nx,
nz is the refractive index at a wavelength of 550 nm in the thickness direction of the second retardation layer 32, and when nx=ny, nx is the refractive index in any direction in the plane of the second retardation layer 32. and can be
d is the film thickness of the second retardation layer 32; ]

Since the

display devices

3 and 4 have the second retardation layer 32, as indicated by the arrows in FIG. can be reduced. The reflected light incident from an oblique direction is mainly light emitted from a region of the display element 41 away from the light receiving sensor 42 and reflected by the high refractive index layer 45 in a plan view of the display unit 40 . . The amount of reflected light incident from an oblique direction tends to be reduced when the thickness direction retardation value Rth (550) of the second retardation layer 32 is within the above range. Thereby, malfunction of the light receiving sensor 42 can be further suppressed.

As shown in FIGS. 3 and 4, the first bonding layer 21 may be provided between the high refractive index layer 45 and the second retardation layer 32, the high refractive index layer 45 and the second retardation layer It may be in direct contact with layer 32 . The

display devices

3 and 4 and the

optical laminates

53 and 54 have a sixth bonding layer 26 between the second retardation layer 32 and the first retardation layer 31, and the second retardation layer 32 and the first Preferably, the retardation layer 31 is in direct contact with the sixth bonding layer 26 .

In the

display devices

3 and 4 and the

optical laminates

53 and 54 shown in FIGS. However, if the second retardation layer 32 is provided between the high refractive index layer 45 and the linear polarizing layer 11, it is not limited to this. For example, the second retardation layer 32 may be provided 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 view shape of the second retardation layer 32 is preferably the same as the planar view shape of the first retardation layer 31 .

Even when the

display devices

3 and 4 and the

optical laminates

53 and 54 have the second retardation layer 32 between the first retardation layer 31 and the linearly polarizing layer 11, the

display devices

3 and 4 and the

optical laminates

53 and 54 54 can have a sixth bonding layer 26 between the second retardation layer 32 and the first retardation layer 31 . Further, the second bonding layer 22 may be provided between the second retardation layer 32 and the linear polarizing layer 11. For example, the second bonding layer 22 includes the second retardation layer 32 and the first It may be in direct contact with the protective film 12 .

In the following, the display device and the layers constituting the display device described above will be described in more detail.

(Display device)
The display device described above can be used as a liquid crystal display device or an organic EL (electroluminescence) display device. The display device may be a mobile terminal such as a smart phone and a tablet. The display device may be a bendable flexible display.

The outer shape of the display area of the display device in a plan view is not particularly limited, but may be a rectangle, a square, a polygon other than a rectangle or a square, or a rounded shape having rounded corners (a shape having R). may The rectangular, square, polygonal, or rounded display area may have a through hole for arranging a camera or the like.

(Display element)
The display element may be a liquid crystal display element or an organic EL display element. The liquid crystal display element can have, for example, a liquid crystal cell having a liquid crystal layer sandwiched between two cell substrates, a backlight, and the like. An organic EL display element can have, for example, a light-emitting layer and electrodes.

The light emitted from the display element is preferably light with a wavelength of 320 nm or more and 4000 nm or less, more preferably light with a wavelength of 380 nm or more and 780 nm or less (visible light region), and light with a wavelength of 380 nm or more and 720 nm or less. good too.

(Light receiving sensor)
The light receiving sensor detects incident light. The light receiving sensor may constitute an illuminance sensor that detects the illuminance around the display device, a proximity sensor that detects the proximity of an object, a camera, or the like. The light receiving sensor is preferably capable of detecting light with a wavelength of 320 nm or more and 4000 nm or less, and detects light with a wavelength of 380 nm or more and 780 nm or less (visible light region) and/or light with a wavelength of 780 nm or more and 4000 nm or less (infrared region). It is more preferable that it is possible.

(touch sensor panel)
The display device and optical stack may include a touch sensor panel. The touch sensor panel can detect a position touched by a user's finger or the like. Examples of touch sensor panels include touch sensor panels of resistive film type, capacitive coupling type, optical sensor type, ultrasonic wave type, electromagnetic induction coupling type, and surface acoustic wave type. A capacitive touch sensor panel is preferably used.

In the display device and the optical laminate, the touch sensor panel may be provided on the viewing side of the linear polarizing layer (the first retardation layer side of the linear polarizing layer), and provided on the side opposite to the viewing side of the linear polarizing layer. may be When the touch sensor panel is provided on the viewing side of the linear polarizing layer, the touch sensor panel may constitute a high refractive index layer, which will be described later. When the touch sensor panel is provided on the opposite side of the linear polarizing layer to the viewing side, the touch sensor panel is preferably provided between the linear polarizing layer and the display unit.

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

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

The polymer that constitutes the resin plate or resin film is not particularly limited as long as it is a resin that can transmit light. Such polymers include, for example, triacetyl cellulose, acetyl cellulose butyrate, ethylene-vinyl acetate copolymer, propionyl cellulose, butyryl cellulose, acetyl propionyl cellulose, polyester, polystyrene, polyamide, polyetherimide, poly(meth) ) acrylic, polyimide, polyethersulfone, polysulfone, polyethylene, polypropylene, polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetal, polyetherketone, polyetheretherketone, polyethersulfone, polymethyl (meth) Acrylate, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyamideimide and the like. These polymers can be used alone or in combination of two or more. As used herein, (meth)acryl refers to acrylic and/or methacrylic, and (meth)acrylate refers to acrylate and/or methacrylate.

When the front plate is a resin film, the front plate may have a hard coat layer on at least one surface of the resin film. The hard coat layer is, for example, a cured layer of an ultraviolet curable resin. Examples of UV-curable resins include (meth)acrylic resins such as monofunctional (meth)acrylic resins, polyfunctional (meth)acrylic resins, and polyfunctional (meth)acrylic resins having a dendrimer structure; silicone resin; polyester resin; urethane resin; amide resin; epoxy resin and the like. The hard coat layer may contain additives in order to improve strength. The additive is not particularly limited, and may be inorganic fine particles, organic fine particles, or a mixture thereof. When the resin film has hard coat layers on both sides, the composition and thickness of each hard coat layer may be the same or different.

When the front plate is a glass plate or glass film, tempered glass for displays is preferably used.

The above-described touch sensor panel is an example of the touch sensor panel that constitutes the high refractive index layer. When the touch sensor panel constitutes the high refractive index layer, the touch sensor panel has a refractive index of 1.60 or more, preferably 1.70 or more, more preferably 1.90 or more, and usually 2 .70 or less, preferably 2.60 or less, more preferably 2.40 or less.

(First retardation layer, second retardation layer, third retardation layer, fourth retardation layer)
The first retardation layer, the second retardation layer, the third retardation layer, and the fourth retardation layer (hereinafter collectively referred to as "retardation layer".), Even if it is a stretched film Alternatively, it may include a cured product layer of a polymerizable liquid crystal compound.

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

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

When the retardation layer includes the above-mentioned cured product layer, a conventionally known polymerizable liquid crystal compound can be used as the polymerizable liquid crystal compound. A polymerizable liquid crystal compound is a compound having at least one polymerizable group and having liquid crystallinity.

The type of polymerizable liquid crystal compound is not particularly limited, and rod-like liquid crystal compounds, discotic liquid crystal compounds, and mixtures thereof can be used. A cured product layer formed by polymerizing a polymerizable liquid crystal compound develops retardation by curing in a state in which the polymerizable liquid crystal compound is oriented in a suitable direction. When the rod-like polymerizable liquid crystal compound is aligned horizontally or vertically with respect to the planar direction of the display device, the optical axis of the polymerizable liquid crystal compound coincides with the long axis direction of the polymerizable liquid crystal compound. When the discotic polymerizable liquid crystal compound is oriented, the optical axis of the polymerizable liquid crystal compound exists in a direction orthogonal to the discotic surface of the polymerizable liquid crystal compound. As the rod-like polymerizable liquid crystal compound, for example, those described in JP-A-11-513019 (claim 1 etc.) can be preferably used. As the discotic polymerizable liquid crystal compound, JP-A-2007-108732 (paragraphs [0020] to [0067], etc.), JP-A-2010-244038 (paragraphs [0013] to [0108], etc.) described in can be preferably used.

The polymerizable group possessed by the polymerizable liquid crystal compound means a group involved in the polymerization reaction, and is preferably a photopolymerizable group. A photopolymerizable group is a group that can participate in a polymerization reaction by an active radical generated from a photopolymerization initiator, an acid, or the like. Examples of the polymerizable group include vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, (meth)acryloyloxy group, oxiranyl group, oxetanyl group, styryl group and allyl group. . Among them, a (meth)acryloyloxy group, a vinyloxy group, an oxiranyl group and an oxetanyl group are preferred, and an acryloyloxy group is more preferred. The liquid crystallinity of the polymerizable liquid crystal compound may be either thermotropic liquid crystal or lyotropic liquid crystal, and thermotropic liquid crystal may be classified into nematic liquid crystal or smectic liquid crystal according to the degree of order. When two or more types of polymerizable liquid crystal compounds are used in combination to form a cured product layer of the polymerizable liquid crystal compound, at least one type preferably has two or more polymerizable groups in the molecule. As used herein, (meth)acryloyl refers to acryloyl and/or methacryloyl.

When the retardation layer contains the cured product layer, the retardation layer may contain an orientation layer. The orientation layer has an orientation regulating force that orients the polymerizable liquid crystal compound in a desired direction. The alignment layer may be a vertical alignment layer in which the molecular axis of the polymerizable liquid crystal compound is vertically aligned with respect to the in-plane direction of the display device, and the molecular axis of the polymerizable liquid crystal compound is aligned horizontally with respect to the in-plane direction of the display device. It may be a horizontal alignment layer, or an oblique alignment layer in which the molecular axis of the polymerizable liquid crystal compound is obliquely aligned with respect to the plane direction of the display device. When the retardation layer comprises two or more alignment layers, the alignment layers may be the same as each other or different from each other.

The alignment layer has a solvent resistance that does not dissolve when a composition for forming a liquid crystal layer containing a polymerizable liquid crystal compound is applied, etc., and has heat resistance to heat treatment for removing the solvent and aligning the polymerizable liquid crystal compound. things are preferred. Examples of the alignment layer include an alignment polymer layer formed of an alignment polymer, a photo-alignment polymer layer formed of a photo-alignment polymer, and a groove alignment layer having an uneven pattern or a plurality of grooves on the layer surface. can be done.

The cured product layer is formed by applying a composition for forming a retardation layer containing a polymerizable liquid crystal compound and a solvent, and various additives as necessary, onto the alignment layer to form a coating film, and solidifying the coating film. By (curing), a cured product layer of the polymerizable liquid crystal compound can be formed. Alternatively, the composition may be applied onto the substrate layer to form a coating film, and the coating film may be stretched together with the substrate layer to form the cured product layer. The composition may contain a polymerization initiator, a reactive additive, a leveling agent, a polymerization inhibitor, etc., in addition to the polymerizable liquid crystal compound and solvent described above. As the polymerizable liquid crystal compound, solvent, polymerization initiator, reactive additive, leveling agent, polymerization inhibitor, etc., known ones can be appropriately used.

A film formed of a resin material can be used as the base layer, and for example, a film using a resin material described as a thermoplastic resin used to form the first protective film described later can be mentioned. The thickness of the substrate layer is not particularly limited, but in general, it is preferably 1 to 300 μm or less, more preferably 20 to 200 μm, more preferably 30 to 120 μm from the viewpoint of workability such as strength and handleability. is more preferred. The base material layer may be incorporated in the display device together with the cured material layer of the polymerizable liquid crystal compound, the base material layer is peeled off, and only the cured material layer of the polymerizable liquid crystal compound, or the cured material layer and the orientation A layer may be incorporated into a display device. When the substrate layer is incorporated in the display device together with the cured product layer of the polymerizable liquid crystal compound, the thickness of the substrate layer may be less than 30 μm, for example, 25 μm or less.

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

(linear polarizing layer)
The linearly polarizing layer has a property of transmitting linearly polarized light having a plane of vibration perpendicular to the absorption axis when non-polarized light is incident thereon. The linear polarizing layer may be a polyvinyl alcohol-based resin film (hereinafter sometimes referred to as "PVA-based film") in which iodine is adsorbed and oriented, and has a composition containing a compound having absorption anisotropy and liquid crystallinity. It may be a film containing a liquid crystalline polarizing layer formed by applying a substance to a substrate film. The compound having absorption anisotropy and liquid crystallinity may be a mixture of a dye having absorption anisotropy and a compound having liquid crystallinity, or may be a dye having absorption anisotropy and liquid crystallinity.

The linear polarizing layer is preferably a PVA-based film in which iodine is adsorbed and oriented. The linear polarizing layer, which is a PVA-based film, is obtained by subjecting a PVA-based film such as a polyvinyl alcohol film, a partially formalized polyvinyl alcohol film, an ethylene-vinyl acetate copolymer-based partially saponified film, to a dyeing treatment with iodine and a stretching treatment. and the like. If necessary, the PVA-based film having iodine adsorbed and oriented by the dyeing treatment may be treated with an aqueous boric acid solution, followed by a washing step of washing off the aqueous boric acid solution. A known method can be adopted for each step.

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

The saponification degree of the PVA-based resin is usually about 85 to 100 mol%, preferably 98 mol% or more. The PVA-based resin may be modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The average degree of polymerization of the PVA-based resin is usually about 1,000 to 10,000, preferably about 1,500 to 5,000. The degree of saponification and average degree of polymerization of the PVA-based resin can be obtained according to JIS K 6726 (1994). If the average degree of polymerization is less than 1,000, it is difficult to obtain desirable polarizing performance, and if it exceeds 10,000, film workability may be poor.

A method for producing a linear polarizing layer, which is a PVA-based film, involves preparing a base film, applying a solution of a resin such as a PVA-based resin on the base film, and performing drying or the like to remove the solvent. may include a step of forming a resin layer on the substrate. A primer layer can be formed in advance on the surface of the substrate film on which the resin layer is formed. As the base film, a film using a resin material described as a thermoplastic resin used for forming the first protective film, which will be described later, can be used. Examples of the material for the primer layer include a resin obtained by cross-linking the hydrophilic resin used for the linear polarizing layer.

Next, the amount of solvent such as moisture in the resin layer is adjusted as necessary, then the base film and the resin layer are uniaxially stretched, and then the resin layer is dyed with iodine to adsorb and align iodine on the resin layer. . Next, if necessary, the resin layer in which iodine is adsorbed and oriented is treated with an aqueous boric acid solution, followed by a washing step of washing off the aqueous boric acid solution. As a result, a resin layer in which iodine is adsorbed and oriented, that is, a PVA-based film to be a linear polarizing layer is produced. A known method can be adopted for each step.

The amount of boric acid in the boric acid-containing aqueous solution for treating the PVA-based film or resin layer in which iodine is adsorbed and oriented is usually about 2 to 15 parts by mass, preferably 5 to 12 parts by mass, per 100 parts by mass of water. This boric acid-containing aqueous solution preferably contains potassium iodide. The amount of potassium iodide in the boric acid-containing aqueous solution is usually about 0.1 to 15 parts by mass, preferably about 5 to 12 parts by mass, per 100 parts by mass of water. The immersion time in the boric acid-containing aqueous solution is usually about 60 to 1,200 seconds, preferably about 150 to 600 seconds, more preferably about 200 to 400 seconds. The temperature of the boric acid-containing aqueous solution is usually 50°C or higher, preferably 50 to 85°C, more preferably 60 to 80°C.

Uniaxial stretching of the PVA-based film, the substrate film and the resin layer may be performed before dyeing, during dyeing, or during boric acid treatment after dyeing. Uniaxial stretching may be performed in each of a plurality of stages. The PVA-based film, the base film and the resin layer may be uniaxially stretched in the MD direction (film transport direction). You may stretch|stretch uniaxially using. Moreover, the PVA-based film, the base film and the resin layer may be uniaxially stretched in the TD direction (the direction perpendicular to the film transport direction), in which case a so-called tenter method can be used. The stretching may be dry stretching in which the film is stretched in the atmosphere, or may be wet stretching in which the PVA-based film or resin layer is swollen with a solvent and then stretched. In order to exhibit the performance of the linear polarizing layer, the draw ratio is 4 times or more, preferably 5 times or more, and particularly preferably 5.5 times or more. Although there is no particular upper limit for the draw ratio, it is preferably 8 times or less from the viewpoint of suppressing breakage and the like.

A linear polarizing layer produced by a manufacturing method using a base film can be obtained by peeling off the base film after laminating the first protective film or the second protective film. According to this method, the thickness of the linear polarizing layer can be further reduced.

The thickness of the linear polarizing layer, which is a PVA-based film, is preferably 1 μm or more, may be 2 μm or more, or may be 5 μm or more, and is preferably 30 μm or less, and 15 μm or less. is more preferable, and may be 10 μm or less, or may be 8 μm or less.

A film containing a liquid crystalline polarizing layer is obtained by coating a base film with a composition containing a dye having liquid crystallinity and absorption anisotropy, or a composition containing a dye having absorption anisotropy and a polymerizable liquid crystal. A linear polarizing layer obtained by Examples of the base film include a film using a resin material described as a thermoplastic resin used for forming the first protective film, which will be described later. Examples of the film containing a liquid crystalline polarizing layer include the polarizing layer described in JP-A-2013-33249.

The total thickness of the substrate film and the linearly polarizing layer formed as described above is preferably as small as possible. It is 5 μm or less, more preferably 0.5 to 3 μm.

The linear polarizing layer (PVA-based film, film containing a liquid crystalline polarizing layer) obtained as described above is coated on one or both sides thereof via an adhesive with a first protective film and/or a second protective film to be described later. A linear polarizing plate in which films are laminated may be incorporated in a display device. In the film containing the liquid crystalline polarizing layer, the above base film may be used as the first protective film or the second protective film.

(First protective film, second protective film)
As the first protective film and the second protective film, for example, a film formed from a thermoplastic resin that is excellent in transparency, mechanical strength, thermal stability, water barrier properties, isotropy, stretchability, etc. is used. Specific examples of thermoplastic resins include cellulose resins such as triacetyl cellulose; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polyethersulfone resins; polysulfone resins; polycarbonate resins; polyamide resins such as nylon and aromatic polyamides; Resin; polyolefin resin such as polyethylene, polypropylene, ethylene/propylene copolymer; cyclic polyolefin resin having cyclo-type and norbornene structure (also referred to as norbornene-based resin); (meth)acrylic resin; polyarylate resin; polystyrene resin; polyvinyl alcohol Resins, as well as mixtures thereof, may be mentioned. The resin compositions of the first protective film and the second protective film may be the same or different.

The first protective film may have antireflection properties, antiglare properties, hard coat properties, etc. (Hereinafter, a protective film having such properties may be referred to as a "functional protective film".). When the first protective film is not a functional protective film, one surface of the linear polarizing plate may be provided with a surface functional layer such as an antireflection layer, an antiglare layer, or a hard coat layer. The surface functional layer is preferably provided so as to be in direct contact with the first protective film. The surface functional layer is preferably provided on the opposite side of the first protective film from the linearly polarizing layer side.

The first protective film and the second protective film are each independently preferably 3 μm or more, more preferably 5 μm or more, and preferably 50 μm or less, more preferably 30 μm or less. preferable.

(First bonding layer, second bonding layer, third bonding layer, fourth bonding layer, fifth bonding layer, sixth bonding layer)
The first bonding layer, the second bonding layer, the third bonding layer, the fourth bonding layer, the fifth bonding layer, the sixth bonding layer, and the bonding layer (hereinafter collectively referred to as "bonding ) are each independently a pressure-sensitive adhesive layer or an adhesive layer.

When the lamination layer is an adhesive layer, it is an adhesive layer formed using an adhesive composition. The pressure-sensitive adhesive composition or the reaction product of the pressure-sensitive adhesive composition develops adhesiveness by attaching itself to an adherend such as a metal layer, and is referred to as a so-called pressure-sensitive adhesive. be. Moreover, the adhesive layer formed using the active-energy-ray-curable adhesive composition mentioned later can adjust a crosslinking degree and adhesive strength by irradiating an active-energy-ray.

As the adhesive composition, conventionally known adhesives having excellent optical transparency can be used without particular limitation. For example, adhesives containing base polymers such as acrylic polymers, urethane polymers, silicone polymers, and polyvinyl ethers. Compositions can be used. The adhesive composition may also be an active energy ray-curable adhesive composition, a heat-curable adhesive composition, or the like. Among these, a pressure-sensitive adhesive composition using an acrylic resin as a base polymer, which is excellent in transparency, adhesive strength, removability (reworkability), weather resistance, heat resistance, etc., is preferable. The pressure-sensitive adhesive layer preferably comprises a reaction product of a pressure-sensitive adhesive composition containing a (meth)acrylic resin, a cross-linking agent and a silane compound, and may contain other components.

The adhesive layer may be formed using an active energy ray-curable adhesive. The active energy ray-curable pressure-sensitive adhesive is obtained by blending an ultraviolet-curable compound such as a polyfunctional acrylate with the above-described pressure-sensitive adhesive composition, forming a pressure-sensitive adhesive layer, and then irradiating ultraviolet rays to cure the pressure-sensitive adhesive layer. An adhesive layer can be formed. Active energy ray-curable pressure-sensitive adhesives have the property of being cured by being irradiated with energy rays such as ultraviolet rays and electron beams. Since the active energy ray-curable adhesive has adhesiveness even before energy ray irradiation, it adheres to the adherend and has the property that it can be cured by energy ray irradiation to adjust the adhesive strength. .

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

When the lamination layer is an adhesive layer, the adhesive layer can be formed by curing the curable component in the adhesive composition. Examples of the adhesive composition for forming the adhesive layer include adhesives other than pressure-sensitive adhesives (adhesives), such as water-based adhesives and active energy ray-curable adhesives.

Examples of water-based adhesives include adhesives in which polyvinyl alcohol resin is dissolved or dispersed in water. The method of drying when a water-based adhesive is used is not particularly limited. For example, a method of drying using a hot air dryer or an infrared ray dryer can be employed.

Active energy ray-curable adhesives include, for example, solvent-free active energy ray-curable adhesives containing curable compounds that are cured by irradiation with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays. mentioned. Adhesion between layers can be improved by using a non-solvent active energy ray-curable adhesive.

The active energy ray-curable adhesive preferably contains either one or both of a cationic polymerizable curable compound and a radically polymerizable curable compound because it exhibits good adhesiveness. The active energy ray-curable adhesive can further contain a cationic polymerization initiator such as a photocationic polymerization initiator or a radical polymerization initiator for initiating the curing reaction of the curable compound.

Examples of cationic polymerizable curable compounds include alicyclic epoxy compounds having an epoxy group bonded to an alicyclic ring, and polyfunctional aliphatic epoxy compounds having two or more epoxy groups and no aromatic ring. , monofunctional epoxy groups having one epoxy group (excluding those contained in alicyclic epoxy compounds), polyfunctional aromatic epoxy compounds having two or more epoxy groups and aromatic rings, etc. compounds; oxetane compounds having one or more oxetane rings in the molecule; and combinations thereof.

Examples of radically polymerizable curable compounds include (meth)acrylic compounds (compounds having one or more (meth)acryloyloxy groups in the molecule), other radically polymerizable double bonds. vinyl-based compounds, or combinations thereof.

The active energy ray-curable adhesive can contain a sensitizer such as a photosensitizer as needed. By using a sensitizer, the reactivity is improved, and the mechanical strength and adhesive strength of the adhesive layer can be further improved. A known sensitizer can be appropriately applied. When a sensitizer is blended, the blending amount is preferably in the range of 0.1 to 20 parts by mass with respect to 100 parts by mass as the total amount of the active energy ray-curable adhesive.

Active energy ray-curable adhesives may optionally contain ion trapping agents, antioxidants, chain transfer agents, tackifiers, thermoplastic resins, fillers, flow control agents, plasticizers, antifoaming agents, and antistatic agents. Additives such as agents, leveling agents, solvents and the like can be included.

When an active energy ray-curable adhesive is used, an adhesive layer can be formed by irradiating an active energy ray such as ultraviolet rays, visible light, electron beams, and X-rays to cure the adhesive coating layer. can. As the active energy ray, ultraviolet rays are preferable, and as a light source in this case, 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, a metal halide lamp, etc. can be used. can.

When the lamination layer is an adhesive layer, the thickness is preferably 0.1 µm or more, and may be 0.5 µm or more, and preferably 10 µm or less, and may be 5 µm or less. .

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

[Measurement of refractive index]
The refractive index of the high refractive index layer was measured at 25° C. using a multi-wavelength Abbe refractometer [“DR-M4” manufactured by Atago Co., Ltd.] at a measurement wavelength of 589 nm.

[Measurement of Visibility Correction Single Transmittance Ty]
For the linearly 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 JASCO Corporation], and the following formula:
Single transmittance (%) = (MD + TD) / 2
A single transmittance at each wavelength was calculated based on .

"MD transmittance" is the transmittance when the direction of polarized light emitted from the Glan-Thompson prism is parallel to the transmission axis of the linearly polarizing layer, and is expressed as "MD" in the above formula. The "TD transmittance" is the transmittance when the direction of the polarized light emitted from the Glan-Thompson prism is perpendicular to the transmission axis of the linearly polarizing layer, and is expressed as "TD" in the above formula. The obtained single transmittance was subjected to luminosity correction with a 2-degree field of view (C light source) of JIS Z 8701: 1999 “Color display method-XYZ color system and X ₁₀ Y ₁₀ Z ₁₀ color system”. A sensitivity-corrected single transmittance was obtained.

[Measurement of in-plane retardation value]
The in-plane retardation values of the first retardation layer and the first protective film were measured using a retardation measuring device (KOBRA-WPR manufactured by Oji Scientific Instruments Co., Ltd.).

[Measurement of thickness direction retardation value]
The thickness direction retardation value of the second retardation layer was measured using a retardation measuring device (KOBRA-WPR manufactured by Oji Scientific Instruments Co., Ltd.). In the measurement, the incident angle of light to the second retardation layer is changed, and the front retardation value of the second retardation layer and the retardation value when tilted 40° around the fast axis are measured. did. The average refractive index at each wavelength was measured using an ellipsometer M-220 manufactured by JASCO Corporation. Further, the thickness of the second retardation layer was measured using an Optical NanoGauge film thickness gauge C12562-01 manufactured by Hamamatsu Photonics K.K. From the front retardation value measured above, the retardation value when tilted 40 ° around the fast axis, the average refractive index, and the thickness of the second retardation layer, Oji Scientific Instruments technical data (https:/ /oji-keisoku.co.jp/cms/uploads/kbr_shiryo04.pdf) to calculate the three-dimensional refractive index. From the obtained three-dimensional refractive index, the thickness direction retardation value Rth of the second retardation layer was calculated according to the above formula (i).

[Measurement of stimulus value Y]
A spectrophotometer [CM2600d manufactured by Konica Minolta] was used to measure the stimulus value Y. Light from a spectrophotometer was incident from the moth-eye film side of the laminate, and the stimulus value Y of the reflected light was measured. Since the reflectance of the moth-eye film is very small, the influence of interfacial reflection between the air and the moth-eye film of the spectrophotometer light can be ignored. In the measurement, it was confirmed that there was no light-reflecting object within 1 m from the light emitting/receiving part of the spectrophotometer, and the measurement was performed in a sufficiently dark environment in order to eliminate the influence of external light. As a result of performing measurement with a spectrophotometer under this measurement environment without a measurement sample (laminate), it was confirmed that the stimulus value Y was 0.1% or less. Therefore, when the stimulus value Y of the laminate is measured under the above measurement environment, light detected by the spectrophotometer is partly absorbed by the polarizer and is only light reflected by the high refractive index layer.

[Example 1]
(Production of polarizer (1))
A polyvinyl alcohol-based resin film having a thickness of 20 μm (average polymerization degree is about 2400 and saponification degree is 99.9 mol % or more) was longitudinally uniaxially stretched at a draw ratio of about 4.5 times by dry stretching. It was immersed in pure water at a temperature of 30° C. for 60 seconds while maintaining the stretched state. Subsequently, while maintaining the strained state, it was immersed in an iodine/potassium iodide aqueous solution having a mass ratio of iodine/potassium iodide/water of 0.05/5/100 and a temperature of 28° C. for 60 seconds. Subsequently, while maintaining the strained state, it was immersed in an aqueous potassium iodide/boric acid solution having a mass ratio of potassium iodide/boric acid/water of 15/5.5/100 and a temperature of 64° C. for 170 seconds. Subsequently, while maintaining the tension, the film was washed with pure water at a temperature of 10°C for 5 seconds, and then dried at an atmospheric temperature of 80°C for 70 seconds while maintaining the tension. A polarizer (1) (linear polarizing layer) having a thickness of 8 μm was produced. The luminous efficiency correction single transmittance Ty of this polarizer (1) was 42.2±0.5%.

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

(Preparation of water-based adhesive)
3 parts by mass of carboxyl group-modified polyvinyl alcohol (“KL-318” manufactured by Kuraray Co., Ltd.) is dissolved in 100 parts by mass of water to obtain an aqueous polyvinyl alcohol solution. Add 1.5 parts by mass (solid content: 0.45 parts by mass) of epoxy resin ["Sumireze Resin 650 (30)" manufactured by Taoka Chemical Co., Ltd., solid content concentration 30 mass%] to prepare a water-based adhesive. Obtained.

(Preparation of linear polarizing plate (1))
A cyclic polyolefin resin film having a thickness of 13 μm was prepared as a first protective film. As the second protective film, a triacetyl cellulose-based resin film [“KC4UY” manufactured by Konica Minolta, Inc., thickness 40 μm] whose surface was not saponified was prepared.

On one surface of the polarizer (1) obtained above, the first protective film (cyclic polyolefin resin film) prepared above is superposed via the water-based adhesive obtained above, and the polarizer (1) is The second protective film (triacetyl cellulose resin film) prepared above is overlaid on the other surface through pure water, passed between a pair of laminating rolls, and then dried by heating at a temperature of 85° C. for 3 minutes. Thereby, the water-based adhesive is cured to form an adhesive layer as a third bonding layer, and a layer structure of first protective film/third bonding layer/polarizer (1)/second protective film is formed. A linear polarizing plate (1) having The in-plane retardation value of the first protective film at a wavelength of 550 nm was 0 nm.

(Production of high refractive index layer)
A film of ITO (Indium Tin Oxide), which is a mixture of indium oxide and tin oxide, is formed on one surface of a non-alkali glass plate ["Eagle XG" manufactured by Corning, refractive index 1.50] by vacuum deposition. An ITO layer having a thickness of 100 μm was formed to obtain a high refractive index layer which is a laminated structure of the alkali-free glass plate and the ITO layer. When the refractive index of this high refractive index layer was measured from the ITO layer side, it was 2.00.

(Production of laminate (1))
Next, the second protective film is peeled off from the linear polarizing plate (1), and the moth-eye film ( Geomatec g.moth) is laminated, and on the first protective film side of the linear polarizing plate (1), the second bonding layer (acrylic adhesive layer with a thickness of 5 μm), the first retardation layer (1), Laminated structure of first bonding layer (25 μm thick acrylic adhesive layer), alkali-free glass plate with refractive index of 1.50 (Eagle XG, refractive index of 1.50) and high refractive index layer (ITO layer) (refractive index 2.00) and a black acrylic plate were laminated in this order to prepare a laminate (1). Laminate (1) was laminated so that the high refractive index layer was on the black acrylic plate side. The space between the high refractive index layer and the black acrylic plate was filled with ethanol dropped before lamination to eliminate an air layer. The first retardation layer (1) was laminated so that the hard coat layer side was on the high refractive index layer side. In the laminate (1), the angle formed by the slow axis of the first retardation layer (1) and the absorption axis of the polarizer (1) of the linear polarizing plate (1) was 45°. The resulting laminate (1) has a layer structure of black acrylic plate/ethanol/high refractive index layer/first bonding layer/first retardation layer (1)/second bonding layer/first protective film/ It was 3rd bonding layer/polarizer (1)/4th bonding layer/moth-eye film. Table 1 shows the results of measuring the stimulus value Y of the laminate (1). The moth-eye film is provided so that the laminate (1) can be evaluated ignoring the influence of interface reflection between the fourth bonding layer and the air layer. A display unit is placed on the opposite side of the layer from the polarizer (1).

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

(Production of laminate (2))
A laminate (2) was obtained in the same manner as in Example 1, except that the first retardation layer (2) was used instead of the first retardation layer (1). The layer structure of the obtained laminate (2) is black acrylic plate / ethanol / high refractive index layer / first bonding layer / first retardation layer (2) / second bonding layer / first protective film / It was 3rd bonding layer/polarizer (1)/4th bonding layer/moth-eye film. Table 1 shows the result of measuring the stimulus value Y of the laminate (2).

[Example 3]
(Preparation of Composition for Forming Horizontal Alignment Film)
5 parts by mass of a photo-alignable polymer having the following structure (described in JP-A-2013-33249) and 95 parts by mass of cyclopentanone (solvent) were mixed and stirred at a temperature of 80° C. for 1 hour to form a horizontal alignment film. A forming composition was obtained.
- Photo-orientable polymer (5 parts by mass):

- Solvent (95 parts by mass): cyclopentanone

(Preparation of polymerizable liquid crystal composition (A1) for forming first retardation layer (3))
The polymerizable liquid crystal compound (X1) and the polymerizable liquid crystal compound (X2) were mixed at a mass ratio of 90:10 to obtain a mixture. With respect to 100 parts of the resulting mixture, 0.1 part of the leveling agent "BYK-361N" (manufactured by BM Chemie) and 2-dimethylamino-2-benzyl-1-(4-morpholinophenyl as a photopolymerization initiator ) 6 parts of butan-1-one (“Irgacure (registered trademark) 369 (Irg369)” manufactured by BASF Japan Ltd.) was added. Furthermore, N-methyl-2-pyrrolidone (NMP) was added so that the solid content concentration was 13%. The mixture was stirred at 80° C. for 1 hour to obtain a polymerizable liquid crystal composition (A1) for forming the first retardation layer (3).

Polymerizable liquid crystal compound (X1):

Polymerizable liquid crystal compound (X2):

(Production of first retardation layer (3))
A COP (cyclic olefin resin) film (ZF-14-50) manufactured by Nippon Zeon Co., Ltd. was subjected to corona treatment, and then the composition for forming a horizontal alignment film obtained above was applied with a bar coater at 80°C. for 1 minute, and using a polarized UV irradiation device (SPOT CURE SP-9; manufactured by Ushio Inc.), polarized UV exposure was performed at a wavelength of 313 nm with an integrated light amount of 100 mJ/cm ² to obtain a horizontal alignment film. rice field. The film thickness of the resulting horizontal alignment film was measured with an ellipsometer and found to be 200 nm.

Subsequently, the polymerizable liquid crystal composition (A1) obtained above was applied using a bar coater on the horizontal alignment film, heated at 120° C. for 60 seconds, and then heated with a high-pressure mercury lamp (Unicure VB-15201BY-A, Ushio Denki Co., Ltd.), the surface coated with the polymerizable liquid crystal composition (A1) is irradiated with ultraviolet rays (in a nitrogen atmosphere, the integrated light amount at a wavelength of 365 nm: 500 mJ/cm ² ), thereby forming a horizontally aligned liquid crystal layer ( A cured product layer of a polymerizable liquid crystal compound) was formed to obtain a laminated structure (A1) having a layer structure of COP film/horizontally aligned film/horizontally aligned liquid crystal layer. After confirming that there is no retardation in the COP film, the in-plane retardation values Re (450) and Re (550) at a wavelength of 450 nm and a wavelength of 550 nm of the laminated structure (A1) are measured in the first retardation layer (3). was measured as in-plane retardation values Re(450) and Re(550), Re(550) was 139 nm. When Re(450)/Re(550) was calculated, it was 0.87, so it was confirmed that this laminate exhibits reverse wavelength dispersion.

The COP film of the laminated structure (A1) was peeled off, and the horizontal alignment film/horizontally aligned liquid crystal layer was used as the first retardation layer (3).

(Production of laminate (3))
A laminate (3) was obtained in the same manner as in Example 1, except that the first retardation layer (3) was used instead of the first retardation layer (1). The first retardation layer (3) was laminated so that the horizontal alignment film side was the high refractive index layer side. The layer structure of the obtained laminate (3) is black acrylic plate / ethanol / high refractive index layer / first bonding layer / first retardation layer (3) / second bonding layer / first protective film / It was 3rd bonding layer/polarizer (1)/4th bonding layer/moth-eye film. Table 1 shows the result of measuring the stimulation value Y of the laminate (3).

[Example 4]
(Preparation of composition for forming vertical alignment film)
The silane coupling agent "KBE-9103" (manufactured by Shin-Etsu Chemical Co., Ltd.) was dissolved in a mixed solvent in which ethanol and water were mixed at a ratio of 9:1 (weight ratio), and the solid content concentration was 1%. A composition for forming an alignment film was obtained.

(Preparation of polymerizable liquid crystal composition (A2) for forming second retardation layer (1))
0.1 part of F-556 as a leveling agent and 3 parts of Irgacure 369 as a polymerization initiator were added to 100 parts of Paliocolor LC242 (registered trademark of BASF), which is a polymerizable liquid crystal compound. Cyclopentanone was added so that the solid content concentration was 13% to obtain a polymerizable liquid crystal composition (A2).

(Production of second retardation layer (1))
After performing corona treatment on COP (cyclic olefin resin) film (ZF-14-50) manufactured by Nippon Zeon Co., Ltd., the composition for forming a vertical alignment film was applied with a bar coater and dried at 120° C. for 1 minute. , to obtain a vertical alignment film. The film thickness of the resulting vertical alignment film was measured with an ellipsometer and found to be 100 nm.

Subsequently, the polymerizable liquid crystal composition (A2) obtained above was applied using a bar coater on the vertical alignment film, dried at 120° C. for 1 minute, and then dried with a high-pressure mercury lamp (Unicure VB-15201BY-A, (manufactured by Ushio Inc.) was used to irradiate ultraviolet rays from the side to which the polymerizable liquid crystal composition (A2) was applied (in a nitrogen atmosphere, integrated light intensity at a wavelength of 365 nm: 500 mJ/cm ² ), thereby producing a vertically aligned liquid crystal. Layers (cured layer of polymerizable liquid crystal compound) were formed to obtain a laminate structure (A2) having a layer structure of COP film/vertically aligned film/vertically aligned liquid crystal layer. After confirming that there is no retardation in the COP film, the thickness direction retardation value Rth (550) of the laminated structure (A2) at a wavelength of 550 nm was calculated as the thickness direction retardation value Rth (550) of the second retardation layer (1). 550), the Rth(550) was -70 nm.

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

(Production of laminate (4))
The horizontally aligned liquid crystal layer side of the first retardation layer (3) and the second retardation layer (1) prepared by the same procedure as in Example 3 are bonded using an ultraviolet curing adhesive, and ultraviolet curing. The mold adhesive is cured to form an adhesive layer (thickness 1 μm) as the sixth bonding layer, and the second retardation layer (1) / sixth bonding layer / first retardation layer (3) A retardation laminate was produced.

A laminate (4) was obtained in the same manner as in Example 1, except that a retardation laminate was used instead of the first retardation layer (1). The retardation laminate was laminated so that the second retardation layer (1) side was on the high refractive index layer (1) side. The layer structure of the obtained laminate (4) is black acrylic plate/ethanol/high refractive index layer/first bonding layer/second retardation layer (1)/sixth bonding layer/first retardation layer (3)/second bonding layer/first protective film/third bonding layer/polarizer (1)/fourth bonding layer/moth-eye film. Table 1 shows the result of measuring the stimulation value Y of the laminate (4).

[Example 5]
(Production of polarizer (2))
A 20 μm-thick polyvinyl alcohol resin film (average polymerization degree is 2400 and saponification degree is 99.9 mol % or more) was longitudinally uniaxially stretched at a draw ratio of about 4.5 times by dry stretching. It was immersed in pure water at a temperature of 30° C. for 60 seconds while maintaining the stretched state. Subsequently, while maintaining the strained state, it was immersed for 60 seconds in an iodine/potassium iodide aqueous solution having a mass ratio of iodine/potassium iodide/water of 0.02/5/100 and a temperature of 28°C. Subsequently, while maintaining the tensioned state, it was immersed for 45 seconds in an aqueous potassium iodide/boric acid solution having a mass ratio of potassium iodide/boric acid/water of 15/5.5/100 and a temperature of 64°C. Subsequently, while maintaining the tension, the film was washed with pure water at a temperature of 10°C for 5 seconds, and then dried in the air at 80°C for 75 seconds while maintaining the tension, so that iodine was adsorbed and oriented on the polyvinyl alcohol resin film. A polarizer (2) (linear polarizing layer) having a thickness of 8 μm was produced. The luminous efficiency correction single transmittance Ty of this polarizer (2) was 46.0±0.5%.

(Production of laminate (5))
A laminate (5) was obtained in the same manner as in Example 1, except that the polarizer (2) was used instead of the polarizer (1). The resulting laminate (5) has a layer structure of black acrylic plate/ethanol/high refractive index layer/first bonding layer/first retardation layer (1)/second bonding layer/first protective film/ It was 3rd bonding layer/polarizer (2)/4th bonding layer/moth-eye film. Table 2 shows the result of measuring the stimulus value Y of the laminate (5).

[Example 6]
A laminate (6) was obtained in the same manner as in Example 2, except that the polarizer (2) was used instead of the polarizer (1). The layer structure of the obtained laminate (6) is black acrylic plate / ethanol / high refractive index layer / first bonding layer / first retardation layer (2) / second bonding layer / first protective film / It was 3rd bonding layer/polarizer (2)/4th bonding layer/moth-eye film. Table 2 shows the result of measuring the stimulus value Y of the laminate (6).

[Example 7]
A laminate (7) was obtained in the same manner as in Example 3, except that the polarizer (2) was used instead of the polarizer (1). The layer structure of the obtained laminate (7) is black acrylic plate / ethanol / high refractive index layer / first bonding layer / first retardation layer (3) / second bonding layer / first protective film / It was 3rd bonding layer/polarizer (2)/4th bonding layer/moth-eye film. Table 2 shows the result of measuring the stimulus value Y of the laminate (7).

[Example 8]
A laminate (8) was obtained in the same manner as in Example 4, except that the polarizer (2) was used instead of the polarizer (1). The layer structure of the obtained laminate (8) is black acrylic plate/ethanol/high refractive index layer/first bonding layer/second retardation layer (1)/sixth bonding layer/first retardation layer. (3)/second bonding layer/first protective film/third bonding layer/polarizer (2)/fourth bonding layer/moth-eye film. Table 2 shows the result of measuring the stimulus value Y of the laminate (8).

[Comparative Example 1]
In the same manner as in Example 5, except that the first retardation layer (1) and the second bonding layer were not laminated, and the high refractive index layer was laminated on the first protective film via the first adhesive layer. to obtain a laminate (9). The layer structure of the obtained laminate (9) is black acrylic plate/ethanol/high refractive index layer/first bonding layer/first protective film/third bonding layer/polarizer (2)/fourth bonding layer. It was a laminate/moth-eye film. Table 2 shows the result of measuring the stimulation value Y of the laminate (9).

From the results shown in Tables 1 and 2, when the in-plane retardation value of the first retardation layer is in the range of 80 nm or more and 170 nm or less, the stimulation value Y becomes small, and the reflected light incident on the light receiving element of the display unit is reduced. It can be seen that it can be reduced. Further, even when the luminosity correction single transmittance Ty of the polarizer included in the laminate is large, the stimulus value Y can be reduced, and the reflected light incident on the light receiving element of the display unit can be reduced. .

1 to 4 display device, 11 linear polarizing layer, 12 first protective film, 13 third retardation layer, 21 first bonding layer, 22 second bonding layer, 23 third bonding layer, 24 fourth bonding layer, 25 fifth bonding layer, 26 sixth bonding layer, 31 first retardation layer, 32 second retardation layer, 40 display unit, 41 display element, 42 light receiving sensor, 45 high refractive index layer, 51 ~ 54 Optical laminate.

Claims

A display device having a high refractive index layer, a first retardation layer, a linear polarization layer, and a display unit in this order from the viewing side,
The refractive index of the high refractive index layer is 1.60 or more,
The display unit has a display element and a light receiving sensor,
The display device, wherein the first retardation layer and the linear polarization layer are laminated so as to cover the display element and the light receiving sensor.
The display device according to claim 1, wherein the first retardation layer covers the entire surface of the linear polarizing layer on the visible side in plan view.
The display device according to claim 1 or 2, wherein the linear polarizing layer has a luminosity correction single transmittance of 42% or more.
The display device according to claim 1 or 2, wherein the angle formed by the slow axis of the first retardation layer and the absorption axis of the linearly polarizing layer is 10° or more and 80° or less.
The display device according to claim 1 or 2, 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.
The display device according to claim 5, wherein the first retardation layer has reverse wavelength dispersion.
Furthermore, having a second retardation layer between the high refractive index layer and the linear polarizing layer,
The second retardation layer is laminated so as to cover the display element and the light receiving sensor,
6. The display device according to claim 5, wherein the second retardation layer has a thickness direction retardation value of −140 nm or more and −20 nm or less at a wavelength of 550 nm.
The display device according to claim 1 or 2, wherein the stimulus value Y of the reflected light when the light emitted from the display element is reflected by the high refractive index layer is 3.45% or more and 4.54% or less.
The display device according to claim 1 or 2, wherein the light-receiving sensor is capable of detecting light with a wavelength of 320 nm or more and 4000 nm or less.
3. The display device according to claim 1, wherein the light emitted from the display element has a wavelength of 320 nm or more and 4000 nm or less.
3. The display device according to claim 1, further comprising a third retardation layer between said linear polarizing layer and said display unit.
An optical laminate having a high refractive index layer, a first retardation layer and a linear polarizing layer in this order,
The optical laminate, wherein the high refractive index layer has a refractive index of 1.60 or more.
The optical layered body according to claim 12, wherein the first retardation layer covers the entire surface of the linear polarizing layer on the viewing side in plan view.
14. The optical layered product according to claim 12 or 13, wherein the linear polarizing layer has a visibility correction single transmittance of 42% or more.
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°
14. The optical laminate according to claim 12 or 13, wherein:
The optical laminate according to claim 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.
The optical laminate according to claim 12 or 13, wherein the first retardation layer has reverse wavelength dispersion.
Furthermore, having a second retardation layer between the high refractive index layer and the linear polarizing layer,
14. The optical laminate according to claim 12, wherein 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.
The optical laminate according to claim 12 or 13, further comprising a third retardation layer on the side opposite to the first retardation layer of the linearly polarizing layer.