WO2021187098A1

WO2021187098A1 - Circular polarizing sheet and optical laminate

Info

Publication number: WO2021187098A1
Application number: PCT/JP2021/008085
Authority: WO
Inventors: 柱烈張; 東輝金; 恩瑛金
Original assignee: 住友化学株式会社
Priority date: 2020-03-19
Filing date: 2021-03-03
Publication date: 2021-09-23
Also published as: CN115280203A; TW202136874A; KR20220150282A

Abstract

The present invention provides a circular polarizing sheet, and an optical laminate and display device provided with the circular polarizing sheet, said circular polarizing sheet being able to suppress differences in the hue of reflected light when viewed from an oblique direction compared to when viewed from the front, even after being exposed to flexion in a display device such as a flexible display. The circular polarizing sheet comprises, in the following order, an optical layer that includes at least a linear polarization layer, a first bonding layer, a first phase difference layer, a second bonding layer, and a second phase difference layer. The first phase difference layer includes a first liquid crystal layer, which is a cured layer of a polymerizable liquid crystal compound. If the modulus of elasticity at a temperature of 25°C of the first bonding layer and the second bonding layer is respectively G'1 [kPa] and G'2 [kPa], and the thickness of the first bonding layer and the second bonding layer is respectively d1 [μm] and d2 [μm], the relationship of formula (1) is satisfied.　(1) G'1/d1 < G'2/d2

Description

Circularly polarizing plate and optical laminate

The present invention relates to a circularly polarizing plate, an optical laminate, and a display device.

As a display device typified by an organic electroluminescence (EL) display device, a flexible display capable of bending the display device by using a flexible material is known (for example, Patent Documents 1 and 2). .. It is known that an organic EL display device uses a circularly polarizing plate or the like to improve antireflection performance in order to suppress a decrease in visibility due to reflection of external light. The circular polarizing plate can be obtained by laminating a linear polarizing plate and a retardation layer, and a cured product layer of a polymerizable liquid crystal compound may be used as the retardation layer.

Japanese Unexamined Patent Publication No. 2019-91021 JP-A-2019-91091

As described above, the circularly polarizing plate provided with the retardation layer of the cured product layer of the polymerizable liquid crystal compound is incorporated into the flexible display as an optical laminate bonded to the front plate or the like constituting the outermost surface of the display device. , The circularly polarizing plate may be repeatedly bent so that the linearly polarizing layer side is on the inside. In a flexible display exposed to such bending, the hue of the reflected light when observed from an oblique direction may be different from the hue (hue) of the reflected light when observed from the front. ..

INDUSTRIAL APPLICABILITY The present invention can suppress the difference in hue of reflected light when observed from an oblique direction as compared with the case where it is observed from the front even after being exposed to bending in a display device such as a flexible display. An object of the present invention is to provide a circular polarizing plate, an optical laminate equipped with the circular polarizing plate, and a display device.

The present invention provides the following circularly polarizing plate, optical laminate, and display device.
[1] A circularly polarizing plate including at least an optical layer including a linearly polarized light layer, a first bonded layer, a first retarded layer, a second bonded layer, and a second retarded layer in this order.
The first retardation layer includes a first liquid crystal layer which is a cured product layer of a polymerizable liquid crystal compound.
The elastic moduli of the first bonding layer and the second bonding layer at a temperature of 25 ° C. are G'1 [kPa] and G'2 [kPa], respectively, and the first bonding layer and the second bonding layer are bonded. A circular polarizing plate satisfying the relationship of the following formula (1) when the thicknesses of the layers are d1 [μm] and d2 [μm], respectively.
G'1 / d1 <G'2 / d2 (1)
[2] The thickness of the first retardation layer is t [μm].
In the cross section of the bent portion of the circularly polarizing plate after the bending test, the position closest to the optical layer side and the farthest from the optical layer side of the surface of the first retardation layer on the first bonding layer side. The circularly polarizing plate according to [1], which satisfies the relationship of the following formula (2) when the distance from the position in the thickness direction is ΔS [μm].
ΔS ≦ 2t (2)
[3] A circularly polarizing plate including at least an optical layer including a linearly polarized light layer, a first bonded layer, a first retarded layer, a second bonded layer, and a second retarded layer in this order.
The first retardation layer includes a first liquid crystal layer which is a cured product layer of a polymerizable liquid crystal compound.
The thickness of the first retardation layer is t [μm], and the thickness is t [μm].
In the cross section of the bent portion of the circularly polarizing plate after the bending test, the position closest to the optical layer side and the farthest from the optical layer side of the surface of the first retardation layer on the first bonding layer side. A circularly polarizing plate that satisfies the relationship of the following equation (2) when the distance from the position in the thickness direction is ΔS [μm].
ΔS ≦ 2t (2)
[4] The circularly polarizing plate according to any one of [1] to [3], wherein the second retardation layer includes a second liquid crystal layer which is a cured product layer of a polymerizable liquid crystal compound.
[5] The circularly polarizing plate according to any one of [1] to [4], wherein the thickness of the first retardation layer is 5 μm or less.
[6] The circular polarizing plate according to any one of [1] to [5], wherein the linearly polarizing layer contains a cured product of a polymerizable liquid crystal compound and a dichroic dye.
[7] The circular polarizing plate according to any one of [1] to [6], wherein the optical layer is a polarizing plate having a protective layer on one side or both sides of the linearly polarizing layer.
[8] The first retardation layer and the second retardation layer are described in the following [a] or [b]:
[A] The first retardation layer is a 1/2 wavelength plate, and the second retardation layer is a 1/4 wavelength plate.
[B] One of the first retardation layer and the second retardation layer is a 1/4 wave plate having a reverse wavelength dispersion, and the other is a positive C plate.
The circularly polarizing plate according to any one of [1] to [7], which satisfies the above relationship.
[9] The first retardation layer is a 1/4 wave plate having anti-wavelength dispersibility.
The circularly polarizing plate according to any one of [1] to [8], wherein the second retardation layer is a positive C plate.
[10] An optical laminate comprising the circularly polarizing plate according to any one of [1] to [9] and a front plate laminated on the optical layer side of the circularly polarizing plate.
[11] A display device provided with the optical laminate according to [10].

According to the present invention, even after being exposed to bending in a display device such as a flexible display, it is possible to suppress the difference in hue of reflected light when observed from an oblique direction as compared with the case where it is observed from the front. It is possible to provide a circular polarizing plate capable of forming.

It is a schematic cross-sectional view which shows typically an example of the circularly polarizing plate of this invention. It is a schematic cross-sectional view for demonstrating an example of the case where the bent state is returned after the bending test of a circularly polarizing plate. It is schematic cross-sectional view which shows typically an example of the optical laminated body of this invention. (A) and (b) are schematic views for explaining the method of the bending test.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments. All of the drawings below are provided to aid in the understanding of the present invention, and the size and shape of each component shown in the drawings may not necessarily match the size and shape of the actual component.

(Circular polarizing plate)
FIG. 1 is a schematic cross-sectional view schematically showing an example of a circularly polarizing plate of the present embodiment. FIG. 2 is a schematic cross-sectional view for explaining an example in which the bent state is returned after the bending test of the circularly polarizing plate. As shown in FIG. 1, the circular polarizing plate 1 includes an optical layer 30 including at least a linearly polarizing layer 31, a first bonded layer 21, a first retardation layer 11, a second bonding layer 22, and a second phase difference. Layer 12 is included in this order. The first retardation layer 11 includes a first liquid crystal layer which is a cured product layer of a polymerizable liquid crystal compound.

The circularly polarizing plate 1 satisfies at least one of and <ii> shown below. The circularly polarizing plate 1 may satisfy only one of and <ii>, but preferably satisfies both and <ii>.

The elastic modulus of the first bonded layer 21 at a temperature of 25 ° C. is G'1 [kPa], and the elastic modulus of the second bonded layer 22 at a temperature of 25 ° C. is G'2 [kPa]. When the thickness of the first bonded layer 21 is d1 [μm] and the thickness of the second bonded layer 22 is d2 [μm], the circular polarizing plate 1 has the following formula (1):
G'1 / d1 <G'2 / d2 (1)
Satisfy the relationship.

<Ii> The thickness of the first retardation layer 11 of the circularly polarizing plate 1 is t [μm].
In the cross section of the bent portion of the circularly polarizing plate after the bending test, the position closest to the optical layer 30 side and the farthest from the optical layer 30 side of the surface of the first retardation layer 11 on the first bonding layer 21 side. When the distance in the thickness direction from the position is ΔS [μm], the circularly polarizing plate 1 has the following equation (2):
ΔS ≦ 2t (2)
Satisfy the relationship.

The optical layer 30 may include at least a linearly polarized light layer 31, and may include a polarizing plate having a protective layer on one side or both sides of the linearly polarized light layer 31, or may be a polarizing plate itself.
The linearly polarizing layer 31 may contain a polyvinyl alcohol-based resin film, or may contain a cured product of a polymerizable liquid crystal compound and a dichroic dye. In the circular polarizing plate 1 shown in FIG. 1, a case where the optical layer 30 is a polarizing plate having

protective layers

32 and 33 on both surfaces of the linearly polarizing layer 31 is shown as an example.

The first bonding layer 21 is a layer for bonding the optical layer 30 and the first retardation layer 11, and can be in direct contact with the optical layer 30 and the first retardation layer 11. The first bonding layer 21 is an adhesive layer or an adhesive curing layer, and is preferably an adhesive layer.

The elastic modulus G'1 of the first bonded layer 21 at a temperature of 25 ° C. may be, for example, 10 kPa or more, 20 kPa or more, or 30 kPa or more. The elastic modulus G'1 may be, for example, 3 × 10 ⁶ kPa or less, 2 × 10 ⁶ kPa or less, 1 × 10 ⁶ kPa or less, or 5 × 10 ⁵ kPa or less. It may be 1 × 10 ⁵ kPa or less, it may be 1 × 10 ⁴ kPa or less, it may be 5 × 10 ³ kPa or less, and it may be 3 × 10 ³ kPa or less. It may be 2 × 10 ³ kPa or less, 1 × 10 ³ kPa or less, or 800 kPa or less. The elastic modulus G'1 can be measured by the method described in Examples described later.

When the first bonding layer 21 is an adhesive layer, the elastic modulus G'1 may be, for example, 10 kPa or more, 20 kPa or more, 30 kPa or more, and 5 × may also be ¹⁰ 3 kPa or less, may also be 3 × ¹⁰ 3 kPa or less, may be less 2 × ¹⁰ 3 kPa may be less 1 × ¹⁰ 3 kPa, below 800kPa There may be. When the first bonding layer 21 is an adhesive cured layer, the elastic modulus G'1 may be, for example, 1 × 10 ⁵ kPa or more, 5 × 10 ⁵ kPa or more, and also. It may be 3 × 10 ⁶ kPa or less, 2 × 10 ⁶ kPa or less, or 1 × 10 ⁶ kPa or less.

When the first bonding layer 21 is an adhesive layer, the thickness d1 of the first bonding layer 21 may be, for example, 3 μm or more, 5 μm or more, or 10 μm or more. Further, for example, it may be 50 μm or less, 40 μm or less, 30 μm or less, or 25 μm or less. When the first bonded layer 21 is an adhesive cured layer, the thickness d1 of the first bonded layer 21 may be, for example, 0.01 μm or more, 0.1 μm or more, or 0.5 μm. It may be more than or equal to 1 μm, and may be, for example, 20 μm or less, 15 μm or less, 10 μm or less, or 5 μm or less.

The first retardation layer 11 includes a first liquid crystal layer which is a cured product layer of a polymerizable liquid crystal compound as described above. The first retardation layer 11 may be the first liquid crystal layer itself, or may be a laminate of the first liquid crystal layer and the first alignment layer. When the first retardation layer 11 includes the first alignment layer, the first alignment layer may be provided on the optical layer 30 side of the first liquid crystal layer, and may be provided on the second bonding layer 22 side of the first liquid crystal layer. It may be provided in.

The thickness t of the first retardation layer 11 may be, for example, 0.01 μm or more, 0.05 μm or more, 0.1 μm or more, or 0.5 μm or more. It may be 1 μm or more. The thickness t is preferably 5 μm or less, and may be 4 μm or less, or 3 μm or less.

The second bonding layer 22 is a layer for bonding the first retardation layer 11 and the second retardation layer 12, and is in direct contact with the first retardation layer 11 and the second retardation layer 12. be able to. The second bonding layer 22 is an adhesive layer or an adhesive curing layer, and is preferably an adhesive curing layer.

The elastic modulus G'2 of the second bonded layer 22 at a temperature of 25 ° C. may be, for example, 50 kPa or more, 70 kPa or more, 90 kPa or more, or 100 kPa or more. , 300 kPa or more, or 500 kPa or more. The elastic modulus G'2 may be, for example, 5 × 10 ⁶ kPa or less, 4 × 10 ⁶ kPa or less, 3 × 10 ⁶ kPa or less, and 2.5 × 10 ⁶ It may be kPa or less, 1 × 10 ⁵ kPa or less, 1 × 10 ⁴ kPa or less, 5 × 10 ³ kPa or less, or 3 × 10 ³ kPa or less. It may be 2 × 10 ³ kPa or less, it may be 1 × 10 ³ kPa or less, or it may be 800 kPa or less. The elastic modulus G'2 can be measured by the method described in Examples described later.

When the second bonding layer 22 is an adhesive layer, the elastic modulus G'2 may be, for example, 50 kPa or more, 70 kPa or more, 90 kPa or more, and 5 × may also be ¹⁰ 3 kPa or less, may also be 3 × ¹⁰ 3 kPa or less, may be less 2 × ¹⁰ 3 kPa may be less 1 × ¹⁰ 3 kPa, below 800kPa There may be. When the second bonding layer 22 is an adhesive cured layer, the elastic modulus G'2 may be, for example, 8 × 10 ⁵ kPa or more, 1 × 10 ⁶ kPa or more, and also. It may be 5 × 10 ⁶ kPa or less, 3 × 10 ⁶ kPa or less, or 1 × 10 ⁵ kPa or less.

When the second bonding layer 22 is an adhesive layer, the thickness d2 of the second bonding layer 22 may be, for example, 1 μm or more, 5 μm or more, or 10 μm or more. It may be 15 μm or more, for example, 50 μm or less, 40 μm or less, 30 μm or less, or 25 μm or less. When the second bonded layer 22 is an adhesive cured layer, the thickness d2 of the second bonded layer 22 may be, for example, 0.01 μm or more, 0.1 μm or more, or 0.5 μm. It may be more than or equal to 1 μm, and may be, for example, 20 μm or less, 15 μm or less, 10 μm or less, or 5 μm or less.

The second retardation layer 12 may be a stretched film obtained by stretching a resin film, or may include a second liquid crystal layer which is a cured product layer of a polymerizable liquid crystal compound. When the second retardation layer 12 includes the second liquid crystal layer, the second retardation layer 12 may be the second liquid crystal layer itself, or may be a laminate of the second liquid crystal layer and the second alignment layer. good. When the second alignment layer 12 includes the second alignment layer, the second alignment layer is usually provided on the side opposite to the second bonding layer 22 side of the second liquid crystal layer.

The thickness of the second retardation layer 12 may be, for example, 0.01 μm or more, 5 μm or more, 20 μm or less, or 15 μm or less. When the second retardation layer 12 includes the second liquid crystal layer, the thickness of the second retardation layer may be, for example, 0.01 μm or more, 0.05 μm or more, or 0.1 μm or more. It may be 0.5 μm or more, 1 μm or more, 5 μm or less, 4 μm or less, or 3 μm or less.

The circularly polarizing plate may be incorporated into a flexible display or the like and bent so that the optical layer 30 side is on the inside. In this case, for example, as shown in FIG. 2, waviness may occur in the first retardation layer 11. The waviness generated in the first retardation layer 11 can cause the retardation characteristics of the first retardation layer 11 to be non-uniform when the circularly polarizing plate is observed. Therefore, for example, on the optical layer 30 side of the circularly polarizing plate 1, the hue (hue) of the reflected light when the circularly polarizing plate 1 is observed from an oblique direction as compared with the case where the circularly polarizing plate 1 is observed from the front. It is thought that a phenomenon such as different will occur.

The circularly polarizing plate 1 of the present embodiment satisfies the relationship of the formula (1) described in the above and / or the relationship of the formula (2) described in the above <ii>. Therefore, even when the circularly polarizing plate 1 is bent so that the optical layer 30 side is on the inside and then the bent state is returned to a flat state, the waviness generated in the first retardation layer 11 is suppressed. It is thought that it is. As a result, it is considered that it is possible to suppress the difference in hue of the reflected light depending on the observation direction as described above.

The reason why the waviness of the first retardation layer 11 can be suppressed in the circularly polarizing plate 1 satisfying the relationship of the equation (1) is presumed as follows. When the circularly polarizing plate 1 is bent so that the optical layer 30 side is on the inside, the first bonded layer 21 is compressed so that the first bonded layer 21 expands toward the first retardation layer 11. do. When the first bonded layer 21 expands, the first retardation layer 11 arranged adjacent to the first bonded layer 21 is affected by the expansion and deforms, and the circularly polarizing plate 1 is returned to the state before bending. However, it is considered that the first retardation layer 11 does not return to the state before bending, and the above-mentioned waviness occurs.

In the first bonded layer 21 and the second bonded layer 22, the larger the elastic moduli G'1 and G'2, the easier it is to expand and the more likely it is to become hard. Therefore, by making the elastic modulus G'1 of the first bonded layer 21 relatively small (for example, G'1 <G'2), the first bonded layer 21 expands due to the bending of the circularly polarizing plate 1. Deformation is suppressed, and it becomes easy to suppress deformation of the first retardation layer 11 due to expansion of the first bonding layer 21. Further, the elastic modulus G'2 of the second bonded layer 22 is relatively increased (for example, G'1 <G'2) to harden the second bonded layer 22, and the circularly polarizing plate 1 is bent. It becomes easy to suppress the deformation of the first retardation layer 11 following the expansion of the first bonding layer 21 accompanying the expansion.

On the other hand, in the first bonded layer 21 and the second bonded layer 22, the larger the thicknesses d1 and d2, that is, the smaller the reciprocal value of the thicknesses d1 and d2, the higher the stress relaxation property. Therefore, by making the thickness d1 of the first bonded layer 21 relatively large (for example, d1> d2) and making the value of the reciprocal of the thickness d1 relatively small, the circular polarizing plate 1 is bent. The stress received by the 1-bonded layer 21 is quickly relaxed, and the stress transmitted to the first retardation layer 11 can be easily reduced. Further, by making the thickness d2 of the second bonding layer 22 relatively small (for example, d1> d2) and making the value of the inverse number of the thickness d2 relatively large, the stress received by the second bonding layer 22 is increased. It is difficult to relax, and it becomes easy to suppress the deformation of the first retardation layer 11 due to the expansion of the first bonding layer 21 accompanying the bending of the circularly polarizing plate 1.

In this way, the elastic moduli G'1 and G'2 and the thicknesses d1 and d2 of the first bonding layer 21 and the second bonding layer 22 are adjusted so as to satisfy the relationship of the equation (1), thereby performing optics. It is considered that when the circular polarizing plate 1 is bent so that the layer 30 side is on the inside, the first retardation layer 11 can be suppressed from being deformed and the occurrence of the above-mentioned waviness can be suppressed.

When the circularly polarizing plate 1 satisfies the relationship of the formula (2) described in the above <ii>, the surface of the first retardation layer 11 on the first bonding layer 21 side is wavy in the circularly polarizing plate 1 after the bending test. Is considered to be in a suppressed state. As a result, on the optical layer 30 side of the circularly polarizing plate 1, the hue (hue) of the reflected light when the circularly polarizing plate 1 is observed from an oblique direction is higher than that when the circularly polarizing plate 1 is observed from the front. It is presumed that different things can be suppressed.

ΔS in the formula (2) is the optics of the surface of the first retardation layer 11 on the first bonding layer 21 side in the cross section of the bent portion of the circularly polarizing plate 1 after the bending test, as shown in FIG. It is the distance in the thickness direction between the position closest to the layer 30 side and the position farthest from the optical layer 30 side. The thickness direction is a direction orthogonal to the plane of the circularly polarizing plate 1 (the laminating direction of the circularly polarizing plate 1). The cross section of the bent portion is a cross section parallel to the direction orthogonal to the rotation axis (swing axis) in the bending test on the plane of the circular plate plate 1 before bending. FIG. 4A is a cross section parallel to the paper surface. The bent portion is the range of the gap C1 (FIG. 4 (a)) between the two stages of the bending test of the embodiment described later.

The magnitude of ΔS corresponds to the magnitude of the waviness of the first retardation layer 11 described above, and it is considered that the smaller the ΔS, the more the waviness is suppressed. Therefore, when ΔS satisfies the equation (2), It is considered that the waviness of the first retardation layer 11 is suppressed in the circularly polarizing plate 1 after the bending test. ΔS can be determined based on a microscopic image obtained by observing the bent portion of the circularly polarizing plate 1 after the bending test with a scanning electron microscope, as described in Examples described later.

In the formula (2), ΔS may be, for example, 1.9 t or less, 1.8 t or less, 1.5 t or less, or 1.4 t or less. It may be 1.35t or less, or 1.3t or less. ΔS may be, for example, 0.1 t or more, 0.5 t or more, t or more, or t or more.

In the circularly polarizing plate 1, the first retardation layer 11 and the second retardation layer 12 have the following [a] or [b]:
[A] The first retardation layer 11 is a 1/2 wavelength plate, and the second retardation layer 12 is a 1/4 wavelength plate.
[B] One of the first retardation layer 11 and the second retardation layer 12 is a 1/4 wave plate having an inverse wavelength dispersion, and the other is a positive C plate.
It is preferable to satisfy the relationship of. In the case of the above [b], it is preferable that the first retardation layer 11 is a 1/4 wave plate having a reverse wavelength dispersion and the second retardation layer 12 is a positive C plate.

It is preferable that the circularly polarizing plate 1 is bendable. Being bendable means that the layer constituting the circularly polarizing plate 1 (for example, the first retardation layer 11 and the like) can be bent without causing cracks. It is preferable that the circularly polarizing plate 1 can be bent in the direction in which the optical layer 30 side is inward.

The thickness of the circularly polarizing plate 1 is usually 5 μm or more, may be 10 μm or more, may be 15 μm or more, is preferably 80 μm or less, and more preferably 60 μm or less.

(Optical laminate)
FIG. 3 is a schematic cross-sectional view schematically showing an example of the optical laminate of the present embodiment. As shown in FIG. 3, the optical laminate 5 has a circularly polarizing plate 1 and a front plate 40 laminated on the optical layer 30 side of the circularly polarizing plate 1 via a third bonding layer 23. It is preferable that the optical laminate 5 can be bent in the direction in which the circularly polarizing plate 1 side is on the inside.

The front plate 40 is a plate-like body that can function as a layer for protecting display elements and the like of a display device and can transmit light. In order to make the optical laminate 5 bendable, it is preferable that the plate-shaped body has a resin film or a glass film. The plate-shaped body may be a laminate of a resin film and a glass film. The front plate 40 can be arranged on the outermost surface of the display device.

The third bonded layer 23 can be in direct contact with the front plate 40 and the optical layer 30 of the circularly polarizing plate 1. The third bonding layer 23 is an adhesive layer or an adhesive curing layer.

The optical laminate 5 may have a fourth bonding layer for bonding to a display element or the like of a display device described later on the circular polarizing plate 1 side (second retardation layer side). The fourth bonded layer is an adhesive layer or an adhesive cured layer.

The optical laminate 5 may have a touch sensor panel or the like. The touch sensor panel may be arranged between the front plate 40 and the circularly polarizing plate 1, or may be arranged on the circularly polarizing plate 1 side (second retardation layer side) of the optical laminate 5.

(Display device)
The optical laminate 5 can be incorporated into a display device such as an organic EL display device. The display device can be obtained, for example, by laminating the optical laminate 5 on the display laminate including the display element and the like. The display laminate may include a touch sensor panel or the like in addition to the display element.

The display device may be a mobile terminal such as a smartphone or tablet, or may be a television, a digital photo frame, an electronic signboard, measuring instruments and instruments, office equipment, medical equipment, computer equipment, and the like. The display device is preferably a flexible display.

Hereinafter, each layer of the circularly polarizing plate and the optical laminate will be described in detail.
(Optical layer)
The optical layer includes at least a linearly polarized light layer. In addition to the linear polarizing layer, the optical layer includes a protective layer that protects one or both sides of the linear polarizing layer, a reflective film, a transflective reflective film, a brightness improving film, an optical compensation film, a film with an antiglare function, and the like. You may be.

(Straightly polarized layer)
The linearly polarized light layer has a function of selectively transmitting linearly polarized light in a certain direction from unpolarized light rays such as natural light. The linearly polarizing layer contains a stretched film on which a dichroic dye is adsorbed, a cured product of a polymerizable liquid crystal compound, and a dichroic dye, and the dichroic dye is dispersed in the cured product of the polymerizable liquid crystal compound. An oriented liquid crystal layer and the like can be mentioned. The dichroic dye refers to a dye having a property in which the absorbance in the major axis direction and the absorbance in the minor axis direction of the molecule are different.

(Linear polarizing layer using stretched film)
The stretched film on which the dichroic dye is adsorbed is usually a step of uniaxially stretching the polyvinyl alcohol-based resin film, and the polyvinyl alcohol-based resin film is dyed with a dichroic dye such as iodine to obtain the dichroic dye. It is produced through a step of adsorbing the vinyl alcohol, a step of treating a polyvinyl alcohol-based resin film on which a dichroic dye is adsorbed with an aqueous boric acid solution, and a step of washing with water after the treatment with the aqueous boric acid solution. The stretched film on which the bicolor dye was adsorbed was subjected to a step of applying a coating liquid containing a polyvinyl alcohol-based resin on the base film to obtain a laminated film, a step of uniaxially stretching the obtained laminated film, and uniaxially stretching. A step of adsorbing a bicolor dye on the polyvinyl alcohol-based resin layer of the laminated film, a step of treating the polyvinyl alcohol-based resin layer on which the bicolor dye is adsorbed with a boric acid aqueous solution, and a step of washing with water after the treatment with the boric acid aqueous solution. It may be manufactured through. The obtained film may be used as it is as a linear polarizing layer, or may be used as a linear polarizing plate having a protective layer formed on one side or both sides thereof. The thickness of the linearly polarizing layer thus obtained is preferably 2 μm to 40 μm.

The polyvinyl alcohol-based resin is obtained by saponifying the polyvinyl acetate-based resin. As the polyvinyl acetate-based resin, in addition to polyvinyl acetate which is a homopolymer of vinyl acetate, a copolymer of vinyl acetate and another monomer copolymerizable therewith is used. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and (meth) acrylamides having an ammonium group.

The saponification degree of the polyvinyl alcohol-based resin is usually about 85 to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol-based resin may be modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes can also be used. The degree of polymerization of the polyvinyl alcohol-based resin is usually about 1,000 to 10,000, preferably in the range of 1,500 to 5,000.

A film formed of such a polyvinyl alcohol-based resin is used as a raw film for a linearly polarizing layer. The method for forming the film of the polyvinyl alcohol-based resin is not particularly limited, and the film can be formed by a known method. The film thickness of the polyvinyl alcohol-based raw film can be, for example, about 10 μm to 150 μm.

The uniaxial stretching of the polyvinyl alcohol-based resin film can be performed before dyeing with a dichroic dye, at the same time as dyeing, or after dyeing. When the uniaxial stretching is performed after dyeing, the uniaxial stretching may be performed before the boric acid treatment or during the boric acid treatment. It is also possible to perform uniaxial stretching at these multiple stages. In uniaxial stretching, rolls having different peripheral speeds may be uniaxially stretched, or thermal rolls may be used to uniaxially stretch the rolls. Further, the uniaxial stretching may be a dry stretching in which the stretching is performed in the atmosphere, or a wet stretching in which the polyvinyl alcohol-based resin film is swollen using a solvent. The draw ratio is usually about 3 to 8 times.

The thickness of the linear polarizing plate having the stretched film as a linear polarizing layer and having protective layers on one or both sides thereof may be, for example, 1 μm or more and 100 μm or less, 5 μm or more, or 7 μm or more. Further, it may be 70 μm or less, 50 μm or less, 20 μm or less, or 10 μm or less.

The material of the protective layer provided on one side or both sides of the linear polarizing layer is not particularly limited, but is, for example, cellulose acetate made of a resin such as a cyclic polyolefin resin, triacetyl cellulose (TAC), or diacetyl cellulose. Resins known in the art such as polyester resins, polycarbonate resins, (meth) acrylic resins, and polypropylene resins made of resins such as based resins, polyethylene terephthalates, polyethylene naphthalates, and polybutylene terephthalates can be mentioned. .. From the viewpoint of thinning, the thickness of the protective layer is usually 300 μm or less, preferably 200 μm or less, more preferably 100 μm or less, and usually 5 μm or more, preferably 20 μm or more. .. The protective layer may be a film, and the protective layer which is a film may have a phase difference. When the protective layer is a film, the linearly polarized light layer and the protective layer can be laminated via an adhesive layer or an adhesive curing layer. The pressure-sensitive adhesive layer and the adhesive curing layer can be formed by using a pressure-sensitive adhesive composition or an adhesive composition described later.

(Linearly polarized light layer using a liquid crystal layer)
The polymerizable liquid crystal compound used for forming the liquid crystal layer is a compound having a polymerizable reactive group and exhibiting liquid crystallinity. The polymerizable reactive group is a group involved in the polymerization reaction, and is preferably a photopolymerizable reactive group. The photopolymerizable reactive group refers to a group that can participate in the polymerization reaction by an active radical, an acid, or the like generated from the photopolymerization initiator. Examples of the photopolymerizable functional group include a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group, a methacryloyloxy group, an oxylanyl group, an oxetanyl group and the like. Of these, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxylanyl group and an oxetanyl group are preferable, and an acryloyloxy group is more preferable. The type of the polymerizable liquid crystal compound is not particularly limited, and a rod-shaped liquid crystal compound, a disk-shaped liquid crystal compound, and a mixture thereof can be used. The liquid crystal property of the polymerizable liquid crystal compound may be a thermotropic liquid crystal or a lyotropic liquid crystal, and the phase-ordered structure may be a nematic liquid crystal or a smectic liquid crystal.

The dichroic dye used in the linearly polarized light layer using the liquid crystal layer preferably has an absorption maximum wavelength (λMAX) in the range of 300 to 700 nm. Examples of such a bicolor dye include an acridine dye, an oxazine dye, a cyanine dye, a naphthalene dye, an azo dye, an anthraquinone dye and the like, and among them, the azo dye is preferable. Examples of the azo dye include a monoazo dye, a bisazo dye, a trisazo dye, a tetrakisazo dye, a stillbenazo dye and the like, and a bisazo dye and a trisazo dye are preferable. The dichroic dye may be used alone or in combination of two or more, but it is preferable to combine three or more. In particular, it is more preferable to combine three or more kinds of azo compounds. A part of the dichroic dye may have a reactive group or may have a liquid crystallinity.

For a linearly polarized light layer using a liquid crystal layer, for example, a composition for forming a polarizing layer containing a polymerizable liquid crystal compound and a dichroic dye is applied onto an orientation layer formed on a base material, and the polymerizable liquid crystal compound is polymerized. It can be formed by curing. Alternatively, a linear polarizing layer may be formed by applying a polarizing layer forming composition on a base material to form a coating film and stretching the coating film together with the base material layer. The base material used for forming the linearly polarized light layer may be used as a protective layer for the linearly polarized light layer. Examples of the base material include a resin film, and examples thereof include a film formed by using the material forming the protective layer described above.

Examples of a composition for forming a polarizing layer containing a polymerizable liquid crystal compound and a dichroic dye, and a method for producing a linear polarizing layer using this composition are JP-A-2013-373353 and JP-A-2013-33249. Examples thereof include those described in JP-A-2017-83843. The composition for forming a polarizing layer further contains additives such as a solvent, a polymerization initiator, a cross-linking agent, a leveling agent, an antioxidant, a plasticizer, and a sensitizer, in addition to the polymerizable liquid crystal compound and the dichroic dye. You may be. As each of these components, only one kind may be used, or two or more kinds may be used in combination.

The polymerization initiator that may be contained in the polarizing layer forming composition is a compound that can initiate the polymerization reaction of the polymerizable liquid crystal compound, and is photopolymerizable in that the polymerization reaction can be initiated under lower temperature conditions. Initiators are preferred. Specific examples thereof include photopolymerization initiators capable of generating active radicals or acids by the action of light, and among them, photopolymerization initiators that generate radicals by the action of light are preferable.
The content of the polymerization initiator is preferably 1 part by mass to 10 parts by mass, and more preferably 3 parts by mass to 8 parts by mass with respect to 100 parts by mass of the total amount of the polymerizable liquid crystal compound. Within this range, the reaction of the polymerizable group proceeds sufficiently, and the orientation state of the liquid crystal compound is likely to be stabilized.

The thickness of the linearly polarizing layer using the liquid crystal layer is not particularly limited, but is preferably 20 μm or less, more preferably 10 μm or less, and further preferably 5 μm or less.

The linearly polarized light layer using the liquid crystal layer may have an overcoat layer as a protective layer on one side or both sides of the linearly polarized light layer. The overcoat layer can be provided for the purpose of protecting the linearly polarized light layer and the like. The overcoat layer preferably has excellent solvent resistance, transparency, mechanical strength, thermal stability, shielding property, isotropic property, and the like. The overcoat layer can be formed, for example, by applying a material (composition) for forming the overcoat layer on the linearly polarized light layer. Examples of the material constituting the overcoat layer include a photocurable resin and a water-soluble polymer, and (meth) acrylic resin, polyvinyl alcohol resin, polyamide epoxy resin and the like can be used.

The thickness of the overcoat layer is not particularly limited, but is preferably 20 μm or less, more preferably 15 μm or less, further preferably 10 μm or less, 5 μm or less, and 0. It is 05 μm or more, and may be 0.5 μm or more.

(1st retardation layer, 2nd retardation layer)
The first retardation layer includes a first liquid crystal layer which is a cured product layer of a polymerizable liquid crystal compound. As the polymerizable liquid crystal compound, for example, those described above can be used. When the second retardation layer contains a second liquid crystal layer which is a cured product layer of the polymerizable liquid crystal compound, as the polymerizable liquid crystal compound, for example, those described above can be used. The polymerizable liquid crystal compound forming the linearly polarized light layer, the polymerizable liquid crystal compound forming the first retardation layer, and the polymerizable liquid crystal compound forming the second retardation layer may be the same as each other. Only some may be the same or all may be different.

When the second retardation layer is a stretched film obtained by stretching a resin film, examples of the resin film include the resin film exemplified in the above-mentioned protective layer.

The first retardation layer and the second retardation layer (hereinafter, both may be collectively referred to as "phase difference layer") are, for example, a composition for forming a retardation layer containing a polymerizable liquid crystal compound on a base material layer. It can be formed by applying a substance and polymerizing and curing a polymerizable liquid crystal compound. The base material layer used to form the retardation layer may be included in the circularly polarizing plate. As the base material layer, for example, the resin film described in the above-mentioned protective layer can be used.

The first retardation layer may be a laminate of the first liquid crystal layer and the first alignment layer as described above.
When the second retardation layer includes the second liquid crystal layer, the second retardation layer may be a laminate of the second liquid crystal layer and the second alignment layer as described above.

(1st oriented layer, 2nd oriented layer)
The first alignment layer and the second alignment layer (hereinafter, both may be collectively referred to as "alignment layer") have an orientation regulating force for aligning the polymerizable liquid crystal compound in a desired direction. Examples of the oriented layer include an oriented polymer layer formed of an oriented polymer, a photo-oriented polymer layer formed of a photo-aligned polymer, and a grub-oriented layer having an uneven pattern or a plurality of grubs (grooves) on the layer surface. Can be done. The thickness of the alignment layer is usually 10 to 500 nm, preferably 10 to 200 nm.

(1st bonding layer, 2nd bonding layer, 3rd bonding layer, 4th bonding layer)
The first to fourth bonded layers are an adhesive layer or an adhesive cured layer. The pressure-sensitive adhesive layer can be formed by using a known pressure-sensitive adhesive composition. The adhesive cured layer can be formed by using a known adhesive composition.

Examples of the pressure-sensitive adhesive composition include pressure-sensitive adhesive compositions containing resins such as (meth) acrylic, rubber, urethane, ester, silicone, and polyvinyl ether as main components. Among them, a pressure-sensitive adhesive composition using a (meth) acrylic resin having excellent transparency, weather resistance, heat resistance and the like as a base polymer is preferable. The pressure-sensitive adhesive composition may be an active energy ray-curable type or a thermosetting type.

Examples of the (meth) acrylic resin (base polymer) used in the pressure-sensitive adhesive composition include butyl (meth) acrylate, ethyl (meth) acrylate, isooctyl (meth) acrylate, and 2- (meth) acrylate. A polymer or copolymer having one or more (meth) acrylic acid esters such as ethylhexyl as a monomer is preferably used. It is preferable that the base polymer is copolymerized with a polar monomer. Examples of the polar monomer include (meth) acrylic acid, 2-hydroxypropyl (meth) acrylate, hydroxyethyl (meth) acrylate, (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylate, and glycidyl (). Examples thereof include monomers having a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group and the like, such as meta) acrylate.

The pressure-sensitive adhesive composition may contain only the above-mentioned base polymer, but usually further contains a cross-linking agent. The cross-linking agent is a divalent or higher metal ion that forms a carboxylic acid metal salt with a carboxyl group; a polyamine compound that forms an amide bond with a carboxyl group; poly. Epoxy compounds and polyols that form an ester bond with a carboxyl group; polyisocyanate compounds that form an amide bond with a carboxyl group are exemplified. Of these, polyisocyanate compounds are preferable.

The active energy ray-curable pressure-sensitive adhesive composition has a property of being cured by being irradiated with active energy rays such as ultraviolet rays and electron beams, and has adhesiveness even before irradiation with active energy rays. It is a pressure-sensitive adhesive composition having the property of being able to adhere to an adherend such as, etc., and being cured by irradiation with active energy rays to adjust the adhesion force. The active energy ray-curable pressure-sensitive adhesive composition is preferably an ultraviolet-curable type. The active energy ray-curable pressure-sensitive adhesive composition further contains an active energy ray-polymerizable compound in addition to the base polymer and the cross-linking agent. Further, if necessary, a photopolymerization initiator, a photosensitizer, or the like may be contained.

The pressure-sensitive adhesive composition includes fine particles for imparting light scattering, beads (resin beads, glass beads, etc.), glass fibers, resins other than the base polymer, pressure-sensitive adhesives, fillers (metal powders and other inorganic powders). Etc.), antioxidants, UV absorbers, dyes, pigments, colorants, antifoaming agents, corrosion inhibitors, photopolymerization initiators and other additives can be included.

The pressure-sensitive adhesive layer can be formed by applying an organic solvent diluent of the above-mentioned pressure-sensitive adhesive composition on a substrate and drying it. When the active energy ray-curable pressure-sensitive adhesive composition is used, the formed pressure-sensitive adhesive layer can be irradiated with active energy rays to obtain a cured product having a desired degree of curing.

Examples of the adhesive composition include water-based adhesives, active energy ray-curable adhesives, natural rubber adhesives, α-olefin adhesives, urethane resin adhesives, ethylene-vinyl acetate resin emulsion adhesives, and ethylene-. Vinyl acetate resin hot melt adhesive, epoxy resin adhesive, vinyl chloride resin solvent adhesive, chloroprene rubber adhesive, cyanoacrylate adhesive, silicone adhesive, styrene-butadiene rubber solvent adhesive, nitrile Rubber adhesives, nitrocellulose adhesives, reactive hot melt adhesives, phenol resin adhesives, modified silicone adhesives, polyester hot melt adhesives, polyamide resin hot melt adhesives, polyimide adhesives, polyurethane Resin Hotlt Adhesive, Polyolefin Resin Hot Melt Adhesive, Polyvinyl Acetate Resin Solvent Adhesive, Polystyrene Resin Solvent Adhesive, Polypoly Alcohol Adhesive, Polypolypyrrolidone Resin Adhesive, Polyvinyl Butyral Adhesive, Polybenzimidazole Examples thereof include adhesives, polymethacrylate resin solvent-based adhesives, melamine resin-based adhesives, urea resin-based adhesives, resorcinol-based adhesives, and the like. Such an adhesive can be used alone or in combination of two or more.

Examples of the water-based adhesive include a polyvinyl alcohol-based resin aqueous solution, a water-based two-component urethane-based emulsion adhesive, and the like. The active energy ray-curable adhesive is an adhesive that cures by irradiating with active energy rays such as ultraviolet rays, and includes, for example, a polymerizable compound and a photopolymerizable initiator, a photoreactive resin, and the like. Examples thereof include those containing a binder resin and a photoreactive cross-linking agent. Examples of the polymerizable compound include photopolymerizable monomers such as a photocurable epoxy monomer, a photocurable (meth) acrylic monomer, and a photocurable urethane monomer, and oligomers derived from these monomers. .. Examples of the photopolymerization initiator include substances that generate active species such as neutral radicals, anion radicals, and cationic radicals by irradiating with active energy rays such as ultraviolet rays.

(Front plate)
The material and thickness of the front plate are not limited as long as it is a plate-like body capable of transmitting light. The front plate may be composed of only one layer, or may be composed of two or more layers. Examples of the front plate include a resin plate-like body (for example, a resin plate, a resin sheet, a resin film, etc.) and a glass plate-like body (for example, a glass plate, a glass film, etc.). The front plate can form the outermost surface of the display device. Further, the front plate may be a resin film or a resin film with a hard coat layer in which a hard coat layer is provided on at least one surface of the resin film to further improve the hardness. When a resin film with a hard coat layer is used, it is preferable that the hard coat layer is provided so as to be arranged on the outermost surface of the display device. Further, the front plate may have a blue light cut function, a viewing angle adjusting function, and the like.

When the front plate contains a resin film, it is preferable that the third bonding layer in the optical laminate is provided in contact with the resin film. For example, when the front plate includes a resin film with a hard coat layer having a hard coat layer on one surface of the resin film, the third bonding layer in the optical laminate is provided in contact with the resin film of the front plate. Is preferable.

The resin film forming the front plate is not limited as long as it is a resin film capable of transmitting light. 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, polyether. Sulfone, polysulfone, polyethylene, polypropylene, polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetal, polyether ketone, polyether ether ketone, polyether sulfone, polymethyl (meth) acrylate, polyethylene terephthalate, polybutylene Examples thereof include films formed of polymers such as terephthalate, polyethylene naphthalate, polycarbonate and polyamideimide. These polymers can be used alone or in admixture of two or more. When the display device is a flexible display, a resin film made of a polymer such as polyimide, polyamide, or polyamide-imide, which has excellent flexibility and can be configured to have high strength and high transparency. Is preferably used.

The front plate may be a resin film having a hard coat layer from the viewpoint of hardness. The hard coat layer may be formed on one surface of the resin film or may be formed on both sides. By providing the hard coat layer, hardness and scratch resistance can be improved. The hard coat layer is, for example, a cured layer of an ultraviolet curable resin. Examples of the ultraviolet curable resin include (meth) acrylic resins such as monofunctional (meth) acrylic resins, polyfunctional (meth) acrylic resins, and polyfunctional (meth) acrylic resins having a dendrimer structure (meth). ) Acrylic resin; Silicone resin; Polyester resin; Urethane resin; Amid resin; Epoxy resin and the like. The hard coat layer may contain additives to improve strength. The additive is not particularly limited, and examples thereof include inorganic fine particles, organic fine particles, or a mixture thereof. When the hard coat layers are provided on both sides of the resin film, the composition and thickness of the hard coat layers may be the same as each other or different from each other.

When the front plate is a glass plate, tempered glass for a display is preferably used as the glass plate. By using a glass plate, a front plate having excellent mechanical strength and surface hardness can be constructed.

The thickness of the front plate may be, for example, 10 μm or more and 300 μm or less, preferably 20 μm or more and 200 μm or less, and more preferably 30 μm or more and 100 μm or less.

(Touch sensor panel)
The touch sensor panel is a sensor that can detect the touched position. The detection method of the touch sensor panel is not limited, and touch sensor panels such as a resistive film method, a capacitance coupling method, an optical sensor method, an ultrasonic method, an electromagnetic induction coupling method, and a surface acoustic wave method are exemplified. Of these, the touch sensor panel of the resistance film type and the capacitance coupling type is preferably used because of its low cost.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these examples. Unless otherwise specified, "%" and "part" in Examples and Comparative Examples are mass% and parts by mass.

[Measurement of thickness]
The thicknesses of the linearly polarized light layer, each oriented layer, and each retardation layer were measured using a laser microscope (OLS3000 manufactured by Olympus Corporation). Thicknesses other than the above were measured using a contact type film thickness measuring device (manufactured by Nikon Corporation, MS-5C).

[Measurement of elastic modulus]
(Measurement of elastic modulus of adhesive layer)
The elastic modulus at a temperature of 25 ° C. when the first bonding layer and the second bonding layer were adhesive layers was determined by the following procedure. After cutting the pressure-sensitive adhesive sheet provided with the pressure-sensitive adhesive layer to be the first bonding layer or the second bonding layer into a width of 30 mm and a length of 30 mm, the light separate film (light SP film) is peeled off to obtain a thickness of 150 μm. A plurality of pressure-sensitive adhesive layers were laminated so as to be. The laminated pressure-sensitive adhesive layer was attached to a glass plate. Using a viscoelasticity measuring device (Anton Parr, MCR-301), the laminated adhesive layer and the measuring chip are joined, and the frequency is 1.0 Hz and the deformation amount is 1% in the temperature range of -20 ° C to 100 ° C. The measurement was carried out under the condition of a temperature rising rate of 5 ° C./min, and the storage elastic modulus at a temperature of 25 ° C. and a relative humidity of 50% was determined as the elastic modulus.

(Measurement of elastic modulus of adhesive cured layer)
The elastic modulus at a temperature of 25 ° C. when the first bonded layer and the second bonded layer were adhesive cured layers was determined by the following procedure. A COP film is applied onto a coating film obtained by applying an adhesive composition for forming an adhesive curing layer to be a first bonding layer or a second bonding layer to glass (thickness 1.0 mm). (Made by Nippon Zeon Co., Ltd., thickness 50 μm) was laminated. ^{After that, the coating film was subjected to a light irradiation intensity of 400 mW / cm 2} and an integrated light amount at a wavelength of 280 to 320 nm using an ultraviolet irradiation device (manufactured by Fusion UV Systems Co., Ltd., equipped with an H valve of an electrodeless ultraviolet lamp). The adhesive composition was cured by irradiating ultraviolet rays so as to be 1500 mJ / cm ^2, and a laminated structure having a layer structure of glass / adhesive cured layer (thickness 2 μm) / COP film was obtained. After peeling the COP film from the laminated structure, the exposed adhesive cured layer is compressed using Nano Indicator (HM-500, manufactured by Fisher Instruments) at a temperature of 25 ° C., a relative humidity of 50%, and a pressure of 1 mN. The elastic modulus was measured and used as the elastic modulus. A Berkovich triangular weight indenter was used as the indenter.

[Evaluation of flexibility]
A pressure-sensitive adhesive layer exposed by peeling a heavy separate film (heavy SP film) on the circularly polarizing plate side from the optical laminates obtained in each Example and Comparative Example, and a thickness of 100 μm assuming a display laminate of a display device. The surface of the polyethylene terephthalate (PET) film of No. 1 was subjected to corona treatment (output 0.3 kW, treatment speed 3 m / min), and then the corona treated surfaces were bonded to each other to obtain a test piece 100. Using this test piece 100, a bending test was performed as follows. 4 (a) and 4 (b) are diagrams schematically showing a method of bending test. A bending device (STS-VRT-500 manufactured by Science Town) equipped with two

stages

501 and 502 was prepared. The test piece 100 was placed on the

stages

501 and 502 so that the front plate side was facing upward (FIG. 4A). The two

stages

501 and 502 were arranged in the gap C1, and the test piece 100 was fixedly arranged so that the center in the width direction was located at the center of the gap C1 (FIG. 4A).
The

stages

501 and 502 are swingable, and initially the two

stages

501 and 502 form the same plane. The two

stages

501 and 502 are rotated 90 degrees upward with position P1 and position P2 as the center of the rotation axis so that the distance C2 between the opposing test pieces 100 is 5 mm (radius of the curved portion in this state). Is approximately 2.5R.) The operation of closing the two stages 501 and 502 (FIG. 4B) and opening the

stages

501 and 502 again is defined as one bending. This operation was repeated, and the flexibility was evaluated by counting the number of times of bending until the test piece 100 was first cracked. The evaluation criteria are as follows.
A: Bending number of 300,000 times or more until crack occurs B: Bending number of 200,000 times or more and less than 300,000 times until crack occurs C: Bending number of 100,000 times or more and less than 200,000 times until crack occurs D: The number of bends before cracking occurs is 50,000 or more and less than 100,000.

[Measurement of ΔS]
From the optical laminates obtained in each Example and Comparative Example, a test piece 100 was prepared by the procedure for evaluating the flexibility described above, and the test piece 100 was bent 200,000 times by the procedure for evaluating the flexibility described above. A bending test was performed to perform the operation. The cross section of the bent portion of the circularly polarizing plate (the range of the gap C1 between the two stages described above) in the test piece 100 after the bending test was observed with a scanning electron microscope. The cross section of the bent portion is the cross section of the circular polarizing plate before bending in the direction parallel to the direction orthogonal to the rotation axis (swing axis) in the bending test (cross section parallel to the paper surface in FIG. 4A). bottom. In the microscopic image of the cross section of the test piece after the bending test, the position and optics of the bent portion of the circularly polarizing plate closest to the optical layer (polarizing plate) side of the surface of the first retardation layer on the first bonding layer side. The distance between the position farthest from the layer (polarizing plate) side in the thickness (lamination) direction of the circular polarizing plate (direction orthogonal to the plane of the circular polarizing plate) was measured as ΔS.

[Visual evaluation]
The test piece 100 (which has been subjected to the bending operation 200,000 times) subjected to the bending test in the above-mentioned procedure for measuring ΔS is set to the state before bending (the flat state as shown in FIG. 4A) and tested. On the front plate side of the piece 100, the hue (hue) of the reflected light when observed from the front and the oblique direction of an angle of 40 ° with respect to the plane of the test piece 100 (when the front direction is 0 °, the angle is 50). The hue (hue) of the reflected light when observed from the direction of °) was visually confirmed and evaluated by comparing the two.
a: As a result of comparison, no difference in hue of reflected light was observed.
b: As a result of comparison, a slight difference was found in the hue of the reflected light.
c: As a result of comparison, a difference was observed in the hue of the reflected light.
d: A crack occurred in the first retardation layer.

The materials used in each Example and Comparative Example were prepared by the following procedure.
[Preparation of polarizing plate (1)]
(Preparation of composition for forming protective layer)
The composition for forming the protective layer for forming the overcoat (OC) layer as the protective layer is 100 parts of water, 3 parts of polyvinyl alcohol resin powder (KL-318, manufactured by Kuraray Co., Ltd., average degree of polymerization 18000), It was prepared by mixing 1.5 parts of a polyamide epoxy resin (SR650 (30), manufactured by Sumika Chemtex Co., Ltd.) as a cross-linking agent.

(Preparation of polarizing plate (1))
A composition for forming an orientation layer was applied to a triacetyl cellulose (TAC) film having a thickness of 25 μm as a protective layer to form a coating film. This coating film was irradiated with polarized UV to form an alignment layer (photoalignment layer) having a thickness of 100 nm. A composition for forming a polarizing layer containing a polymerizable liquid crystal compound and an azo dye was applied onto the alignment layer (the side opposite to the TAC film side) to form a coating film. After the coating film was dried, it was irradiated with ultraviolet rays to form a linearly polarized light layer (1) having a thickness of 1.8 μm.
A composition for forming a protective layer is applied onto the linearly polarizing layer (1) (on the side opposite to the TAC film side) and dried to form an OC layer having a thickness of 1.0 μm as a protective layer, which serves as an optical layer. A polarizing plate (1) was obtained. The polarizing plate (1) was a TAC film, an alignment layer, a linearly polarized light layer (1), and an OC layer laminated in this order.

[Preparation of polarizing plate (2)]
(Preparation of linearly polarized light layer (2))
A long polyvinyl alcohol (PVA) raw film having a thickness of 30 μm (average degree of polymerization 2400, saponification degree 99.9 mol% or more) was immersed in a swelling bath made of pure water (swelling step), and then iodine was added. It was immersed in a dyeing bath containing (dyeing step) and a cross-linking bath containing potassium iodide and boric acid (cross-linking step). In the dyeing step and the cross-linking step, longitudinal uniaxial stretching was performed by stretching between rolls in a bath. The total draw ratio based on the raw film was 5.4 times. Next, the film drawn from the crosslinked bath was immersed in a washing bath made of pure water (washing step), and then introduced into a heating furnace capable of controlling humidity to perform high-temperature and high-humidity treatment (high-temperature and high-humidity treatment). Step), a linearly polarized light layer (2) having a thickness of 12.1 μm was obtained.

(Preparation of polarizing plate (2))
A cyclic polyolefin (COP) film having a thickness of 23 μm as a protective layer and a linearly polarized light layer (2) were subjected to corona treatment (output 0.3 kW, treatment speed 3 m / min), respectively. Using the protective layer forming composition prepared in the above [Preparation of polarizing plate (1)] as an adhesive composition, the corona-treated surface of the COP film and the corona-treated surface of the linearly polarized light layer (2) are bonded together. It was dried at a temperature of 60 ° C. for 2 minutes to obtain a polarizing plate (2) as an optical layer. The polarizing plate (2) was a COP film and a linearly polarizing layer (2) laminated in this order.

[Preparation of the first retardation layer]
(Composition for Forming First Orientation Layer)
The composition for forming the first oriented layer for forming the first oriented layer is prepared by dissolving a polymer having a photoreactive group represented by the following structural formula in cyclopentanone at a concentration of 5%. bottom.

(Composition for Forming First Liquid Crystal Layer)
The composition for forming the first liquid crystal layer for forming the first liquid crystal layer was prepared by mixing each of the following components and stirring the obtained mixture at 80 ° C. for 1 hour.
-Compound represented by the following structural formula: 80 parts

-Compound represented by the following structural formula: 20 parts

-Initiator (Irgacure369, 2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) butane-1-one, manufactured by BASF): 6 parts-Leveling agent (BYK-361N, polyacrylate compound, BYK) -Chemie): 0.1 parts, solvent (cyclopentanone): 400 parts

(Preparation of first retardation layer with base material layer)
The composition for forming a first alignment layer was applied on a polyethylene terephthalate film (PET) having a thickness of 100 μm as a base material layer by a bar coating method, and dried by heating in a drying oven at 80 ° C. for 1 minute. The obtained dry film was subjected to polarized UV irradiation treatment (“SPOT CURE SP-9”, manufactured by Ushio, Inc.) at an integrated light intensity of 100 mJ / cm ^{2 (365 nm standard) to form a first oriented layer.} The polarization direction of the polarized UV was set to 45 ° with respect to the absorption axis of the linearly polarized light layer.

The composition for forming the first liquid crystal layer was applied onto the first alignment layer (the side opposite to the PET film side) by the bar coating method, heated and dried in a drying oven at 120 ° C. for 1 minute, and then cooled to room temperature. The obtained dry film was irradiated with ultraviolet rays having an integrated light intensity of 1000 mJ / cm ² (365 nm standard) to form a first liquid crystal layer having a thickness of 2.0 μm. The first liquid crystal layer was a λ / 4 plate showing a phase difference value of λ / 4 in the in-plane direction, and had anti-wavelength dispersibility. As a result, a first retardation layer with a base material layer in which the PET film and the first retardation layer (first alignment layer, first liquid crystal layer) were laminated in this order was obtained.

[Preparation of second retardation layer]
(Composition for forming a second orientation layer)
The composition for forming the second oriented layer for forming the second oriented layer is composed of 2-phenoxyethyl acrylate, tetrahydrofurfuryl acrylate, dipentaerythritol triacrylate, and bis (2-vinyloxyethyl) ether. , A ratio of 1: 1: 4: 5 was mixed, and LUCIRIN TPO was added as a polymerization initiator to this mixture at a ratio of 4%.

(Composition for Forming Second Liquid Crystal Layer)
The composition for forming the second liquid crystal layer for forming the second liquid crystal layer contains a photopolymerizable nematic liquid crystal compound (manufactured by Merck & Co., Inc., RMM28B) and a solvent so that the solid content is 1 to 1.5 g. Prepared. As the solvent, a mixed solvent was used in which methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), and cyclohexanone (CHN) were mixed at a mass ratio (MEK: MIBK: CHN) of 35:30:35. ..

(Preparation of second retardation layer with base material layer)
A composition for forming a second alignment layer is applied onto a polyethylene terephthalate (PET) film having a thickness of 38 μm as a base material layer so as to have a thickness of 3 μm, and ^{is irradiated with ultraviolet rays of 200 mJ / cm 2} to form a vertically oriented layer. A second oriented layer was formed.

A coating film was formed by applying a composition for forming a second liquid crystal layer on the second alignment layer (the side opposite to the PET film side) with a coating amount of 4 to 5 g (wet) by die coating. The coating film was dried at a drying temperature of 75 ° C. and a drying time of 120 seconds, and then irradiated with ultraviolet rays to form a second liquid crystal layer having a thickness of 3 μm. The second liquid crystal layer was a positive C plate. As a result, a second retardation layer with a base material layer in which the PET film and the second retardation layer (second orientation layer, second liquid crystal layer) were laminated in this order was obtained.

[Preparation of adhesive layer]
The following pressure-sensitive adhesive compositions A to D were prepared, and the pressure-sensitive adhesive layers A to C, D1 and D2 were prepared using this pressure-sensitive adhesive.

(Preparation of Adhesive Composition A and Adhesive Sheet A)
An acrylic polymer (A) was prepared by copolymerizing 70 parts of n-butyl acrylate, 20 parts of methyl acrylate, and 1.0 part of acrylic acid. When the molecular weight of the acrylic polymer (A) was measured, the weight average molecular weight Mw was 1.5 million.

100 parts of acrylic polymer (A), 0.3 parts of cross-linking agent (Nippon Polyurethane Industry Co., Ltd. "Coronate L"), silane coupling agent ("X-12-981" manufactured by Shin-Etsu Chemical Co., Ltd.) 0. Five parts were mixed and ethyl acetate was added so that the total solid content concentration became 10% to obtain a pressure-sensitive adhesive composition A. The release-treated surface of the obtained polyethylene terephthalate film (heavy separate film (heavy SP film), thickness 38 μm) from which the obtained pressure-sensitive adhesive composition A has been release-treated has a thickness of 25 μm after drying using an applicator. Was applied. The coating layer was dried at 100 ° C. for 1 minute to form the pressure-sensitive adhesive layer A. Then, another polyethylene terephthalate film (light separate film (light SP film), thickness 38 μm) that had been released from the mold was attached onto the exposed surface of the pressure-sensitive adhesive layer A. Then, it was cured for 7 days under the conditions of a temperature of 23 ° C. and a relative humidity of 50% RH. As a result, a pressure-sensitive adhesive sheet A composed of a heavy SP film / pressure-sensitive adhesive layer A / light SP film was produced. The elastic modulus of the pressure-sensitive adhesive layer A contained in the pressure-sensitive adhesive sheet A at 25 ° C. was measured. The results are shown in Table 1.

(Preparation of Adhesive Composition B and Adhesive Sheet B)
An acrylic polymer (B) was prepared by copolymerizing 98.9 parts of n-butyl acrylate and 1.1 parts of acrylic acid. When the molecular weight of the acrylic polymer (B) was measured, the weight average molecular weight Mw was 1.36 million.

100 parts of acrylic polymer (B), 2 parts of the first cross-linking agent (“Coronate L” of Nippon Polyurethane Industry Co., Ltd.), and 2 parts of the second cross-linking agent (“TAZM” of Mutual Yakuko Co., Ltd.) 0. 02 parts and 0.5 part of a silane coupling agent (“KBM403” manufactured by Shin-Etsu Chemical Co., Ltd.) were mixed, and ethyl acetate was added so that the total solid content concentration became 10% to obtain the pressure-sensitive adhesive composition B. Obtained. A pressure-sensitive adhesive sheet B composed of a heavy SP film / a pressure-sensitive adhesive layer B / a light SP film was prepared in the same procedure as the preparation of the pressure-sensitive adhesive sheet A except that the pressure-sensitive adhesive composition B was used. The elastic modulus of the pressure-sensitive adhesive layer B contained in the pressure-sensitive adhesive sheet B at 25 ° C. was measured. The results are shown in Table 1.

(Preparation of Adhesive Composition C and Adhesive Sheet C)
An acrylic polymer (C) was prepared by copolymerizing 70.4 parts of n-butyl acrylate, 45 parts of 2-ethylhexyl acrylate, and 1 part of 4-hydroxybutyl acrylate. When the molecular weight of the acrylic polymer (C) was measured, the weight average molecular weight Mw was 800,000.

A cross-linking agent (Nippon Polyurethane Industry Co., Ltd. "Coronate L") 0.4 part and a silane coupling agent (Shin-Etsu Chemical Co., Ltd. "KBM403") 0.5 part are mixed with 100 parts of acrylic polymer (C). Then, ethyl acetate was added so that the total solid content concentration became 10% to obtain a pressure-sensitive adhesive composition C. A pressure-sensitive adhesive sheet C composed of a heavy SP film / a pressure-sensitive adhesive layer C / a light SP film was prepared in the same procedure as the preparation of the pressure-sensitive adhesive sheet A except that the pressure-sensitive adhesive composition C was used. The elastic modulus of the pressure-sensitive adhesive layer C of the pressure-sensitive adhesive sheet C at 25 ° C. was measured. The results are shown in Table 1.

(Preparation of Adhesive Composition D and Adhesive Sheets D1 and D2)
An acrylic polymer (D) was prepared by copolymerizing 68 parts of n-butyl acrylate, 30 parts of methyl acrylate, 1 part of 2-hydroxyethyl acrylate, and 1 part of acrylic acid. When the molecular weight of the acrylic polymer (D) was measured, the weight average molecular weight Mw was 1.35 million.

100 parts of acrylic polymer (D) is mixed with 3 parts of a cross-linking agent (Nippon Polyurethane Industry Co., Ltd. "Coronate L") and 0.5 part of a silane coupling agent ("KBM403" manufactured by Shinetsu Silicon Co., Ltd.). Ethyl acetate was added so that the solid content concentration became 10% to obtain a pressure-sensitive adhesive composition D.

The heavy SP film / pressure-sensitive adhesive layer D1 was prepared in the same procedure as the preparation of the pressure-sensitive adhesive sheet A, except that the pressure-sensitive adhesive composition D was used and the pressure-sensitive adhesive composition D was applied so that the thickness after drying was 15 μm. / An adhesive sheet D1 made of a light SP film was produced. Further, the heavy SP film / adhesive was prepared in the same procedure as the preparation of the pressure-sensitive adhesive sheet A, except that the pressure-sensitive adhesive composition D was used and the pressure-sensitive adhesive composition D was applied so that the thickness after drying was 5 μm. An adhesive sheet D2 made of layer D2 / light SP film was prepared. The elastic moduli of the pressure-sensitive adhesive layers D1 and D2 of the pressure-sensitive adhesive sheets D1 and D2 at 25 ° C. were measured. The results are shown in Table 1.

[Preparation of adhesive composition]
50 parts of the product name "CEL2021P" (manufactured by Daicel) as a curable component, 50 parts of the product name "OXT-221" (manufactured by Toa Synthetic Co., Ltd.), and the product name "CPI-100" (San-) as a photopolymerization initiator. 2.25 parts (manufactured by apro) and 2 parts of 1,4-diethoxynaphthalene as a sensitizer were mixed to prepare an adhesive composition.

[Preparation of front plate]
As the front plate, a film with an HC layer in which a hard coat (HC) layer having a thickness of 10 μm was formed on one side of a polyimide (PI) resin film having a thickness of 50 μm was used. The HC layer was a layer formed from a composition containing a dendrimer compound having a polyfunctional acrylic group at the terminal.

[Example 1]
(Preparation of phase difference laminate (1))
Corona treatment (output 0. 3 kW, processing speed 3 m / min). The adhesive composition prepared above was applied to the corona-treated surface of the first retardation layer with a base material layer, and bonded to the corona-treated surface of the second retardation layer with a base material layer. Using an ultraviolet irradiation device (ultraviolet lamp uses "H valve" manufactured by Fusion UV System Co., Ltd.), ultraviolet rays are emitted so that the light irradiation intensity is 400 mW / cm ² and the integrated light amount at wavelengths of 280 to 320 nm is 400 mJ / cm ^2. The adhesive composition was cured by irradiation to form an adhesive cured layer having a thickness of 2 μm as a second bonding layer. As a result, the PET film, the first retardation layer (first alignment layer, first liquid crystal layer), the second bonding layer (adhesive curing layer), and the second retardation layer (second liquid crystal layer, second alignment layer). ), A retardation laminate (1) in which PET films were laminated in this order was obtained.

(Preparation of circularly polarizing plate (1))
The pressure-sensitive adhesive layer A exposed by peeling off the light SP film of the pressure-sensitive adhesive sheet A prepared above and the OC layer of the polarizing plate (1) prepared above are subjected to corona treatment (output 0.3 kW, processing speed 3 m). After performing (/ min), the corona-treated surfaces were pasted together. Next, the pressure-sensitive adhesive layer A exposed by peeling off the heavy SP film of the pressure-sensitive adhesive sheet A and the PET film on the first retardation layer side of the retardation laminate (1) were peeled off and exposed on the surface. After corona treatment (output 0.3 kW, treatment speed 3 m / min), the corona treated surfaces were bonded to each other, and the pressure-sensitive adhesive layer A was used as the first bonded layer. Then, the PET film on the second retardation layer side was peeled off to obtain a circularly polarizing plate (1). The circular polarizing plate (1) includes a polarizing plate (1) (TAC film, alignment layer, linearly polarized light layer (1), OC layer), a first bonding layer (adhesive layer A), a first retardation layer, and a first. The two bonding layers (adhesive-cured layer) and the second retardation layer were laminated in this order.

In addition, since the first alignment layer may be peeled off at the same time as the first base material layer is peeled off, and the second base material layer may be peeled off at the same time as the second base material layer is peeled off, the circularly polarizing plate ( The layer structures of the first retardation layer and the second retardation layer in 1) do not necessarily match the layer structures of the first retardation layer and the second retardation layer in the retardation laminate (1). The same applies to the following examples and comparative examples.

(Preparation of optical laminate (1))
Corona treatment (output 0.3 kW, processing speed) on the second retardation layer side of the circularly polarizing plate (1) and the pressure-sensitive adhesive layer A exposed by peeling off the light SP film of the pressure-sensitive adhesive sheet A prepared above. After performing (3 m / min), the corona-treated surfaces were bonded to each other to obtain a circularly polarizing plate (1) with an adhesive layer.

Corona treatment (output 0.3 kW, processing speed 3 m) was applied to the PI-based resin film side of the front plate prepared above and the pressure-sensitive adhesive layer A exposed by peeling off the light SP film of the pressure-sensitive adhesive sheet A prepared above. After performing (/ min), the corona-treated surfaces were bonded to each other to obtain a front plate with an adhesive layer.

Next, the adhesive layer A exposed by peeling off the heavy SP film of the front plate with the adhesive layer and the polarizing plate (1) side of the circularly polarizing plate (1) with the adhesive layer are subjected to corona treatment (output 0). After performing .3 kW and processing speed of 3 m / min), the corona-treated surfaces were bonded to each other to obtain an optical laminate (1). The optical laminate (1) was formed by laminating a front plate (HC layer, PI resin film), an adhesive layer A, a circularly polarizing plate (1), an adhesive layer A, and a heavy SP film in this order. ..

Using the obtained optical laminate (1), flexibility was evaluated, ΔS was measured, and visual evaluation was performed. The results are shown in Table 1.

[Example 2]
(Preparation of phase difference laminate (2))
Corona treatment (corona treatment) was applied to the first retardation layer side of the first retardation layer with the base material layer prepared above and the pressure-sensitive adhesive layer D2 exposed by peeling off the light SP film of the pressure-sensitive adhesive sheet D2 prepared above. After the output was 0.3 kW and the processing speed was 3 m / min), the corona-processed surfaces were bonded to each other. Next, the pressure-sensitive adhesive layer D2 exposed by peeling off the heavy SP film of the pressure-sensitive adhesive sheet D2 and the second retardation layer side of the second retardation layer with the base material layer prepared above are subjected to corona treatment (output 0). After performing .3 kW, processing speed 3 m / min), the corona-treated surfaces were bonded to each other, and the pressure-sensitive adhesive layer D2 was used as the second bonded layer to obtain a retardation laminate (2). The retardation laminate (2) includes a PET film, a first retardation layer (first alignment layer, first liquid crystal layer), a second bonding layer (adhesive layer D2), and a second retardation layer (second liquid crystal display). The layer, the second oriented layer), and the PET film were laminated in this order.

(Preparation of circularly polarizing plate (2))
The procedure is the same as that for producing the circularly polarizing plate (1), except that the pressure-sensitive adhesive sheet D1 is used instead of the pressure-sensitive adhesive sheet A and the retardation laminate (2) is used instead of the retardation laminate (1). Obtained a circularly polarizing plate (2). The circular polarizing plate (2) includes a polarizing plate (1) (TAC film, alignment layer, linearly polarized light layer (1), OC layer), a first bonding layer (adhesive layer D1), a first retardation layer, and a first. The two bonding layers (adhesive layer D2) and the second retardation layer were laminated in this order.

(Preparation of optical laminate (2))
An optical laminate (2) was obtained in the same procedure as in the production of the optical laminate (1) except that the circular polarizing plate (2) was used instead of the circular polarizing plate (1). The optical laminate (2) was formed by laminating a front plate (HC layer, PI resin film), an adhesive layer A, a circularly polarizing plate (2), an adhesive layer A, and a heavy SP film in this order. .. The obtained optical laminate (2) was used for evaluation of flexibility, measurement of ΔS, and visual evaluation. The results are shown in Table 1.

[Example 3]
(Preparation of phase difference laminate (3))
A retardation laminate (3) was obtained in the same procedure as in the production of the retardation laminate (2) except that the pressure-sensitive adhesive sheet C prepared above was used instead of the pressure-sensitive adhesive sheet D2. The retardation laminate (3) includes a PET film, a first retardation layer (first alignment layer, first liquid crystal layer), a second bonding layer (adhesive layer C), and a second retardation layer (second liquid crystal display). The layer, the second oriented layer), and the PET film were laminated in this order.

(Preparation of circularly polarizing plate (3))
Fabrication of circularly polarizing plate (1) except that the pressure-sensitive adhesive sheet B prepared above was used instead of the pressure-sensitive adhesive sheet A and the retardation laminate (3) was used instead of the retardation laminate (1). A circularly polarizing plate (3) was obtained in the same procedure as in the above. The circular polarizing plate (3) includes a polarizing plate (1) (TAC film, alignment layer, linearly polarized light layer (1), OC layer), a first bonding layer (adhesive layer B), a first retardation layer, and a first. The two bonding layers (adhesive layer C) and the second retardation layer were laminated in this order.

(Preparation of optical laminate (3))
An optical laminate (3) was obtained in the same procedure as in the production of the optical laminate (1) except that the circular polarizing plate (3) was used instead of the circular polarizing plate (1). The optical laminate (3) was formed by laminating a front plate (HC layer, PI resin film), an adhesive layer A, a circularly polarizing plate (3), an adhesive layer A, and a heavy SP film in this order. .. The obtained optical laminate (3) was used for evaluation of flexibility, measurement of ΔS, and visual evaluation. The results are shown in Table 1.

[Example 4]
(Preparation of circularly polarizing plate (4))
The polarizing plate (2) prepared above is used instead of the polarizing plate (1), the retardation laminate (2) is used instead of the retardation laminate (1), and the pressure-sensitive adhesive sheet A is replaced by the above preparation. The linearly polarizing layer (2) of the polarizing plate (2) and the pressure-sensitive adhesive layer D1 as the first bonding layer were corona-treated (output 0.3 kW, processing speed 3 m / min) using the pressure-sensitive adhesive sheet D1. A circularly polarizing plate (4) was obtained in the same procedure as in the preparation of the circularly polarizing plate (1) except that it was bonded. The circular polarizing plate (4) includes a polarizing plate (2) (COP film, adhesive curing layer, linearly polarized light layer (2) (COP film, adhesive layer, linearly polarized light layer (2)), and a first bonded layer (COP film, adhesive layer, linearly polarized light layer (2)). The pressure-sensitive adhesive layer D1), the first retardation layer, the second bonding layer (adhesive layer D2), and the second retardation layer were laminated in this order.

(Preparation of optical laminate (4))
An optical laminate (4) was obtained in the same procedure as in the production of the optical laminate (1) except that the circular polarizing plate (4) was used instead of the circular polarizing plate (1). The optical laminate (4) was formed by laminating a front plate (HC layer, PI resin film), an adhesive layer A, a circularly polarizing plate (4), an adhesive layer A, and a heavy SP film in this order. .. The obtained optical laminate (4) was used for evaluation of flexibility, measurement of ΔS, and visual evaluation. The results are shown in Table 1.

[Comparative Example 1]
(Preparation of circularly polarizing plate (C1))
Fabrication of circularly polarizing plate (1) except that the retardation laminate (2) was used instead of the retardation laminate (1) and the pressure-sensitive adhesive sheet D2 prepared above was used instead of the pressure-sensitive adhesive sheet A. A circularly polarizing plate (C1) was obtained in the same procedure as in the above. The circular polarizing plate (C1) includes a polarizing plate (1) (TAC film, alignment layer, linearly polarized light layer (1), OC layer), a first bonding layer (adhesive layer D2), a first retardation layer, and a first. The two bonding layers (adhesive layer D2) and the second retardation layer were laminated in this order.

(Preparation of optical laminate (C1))
An optical laminate (C1) was obtained in the same procedure as in the production of the optical laminate (1) except that the circular polarizing plate (C1) was used instead of the circular polarizing plate (1). The optical laminate (C1) consisted of a front plate (HC layer, PI-based resin film), an adhesive layer A, a circularly polarizing plate (C1), an adhesive layer A, and a heavy SP film laminated in this order. .. The obtained optical laminate (C1) was used for evaluation of flexibility, measurement of ΔS, and visual evaluation. The results are shown in Table 1.

[Comparative Example 2]
(Preparation of phase difference laminate (C2))
A retardation laminate (C2) was obtained in the same procedure as in the production of the retardation laminate (2) except that the pressure-sensitive adhesive sheet B prepared above was used instead of the pressure-sensitive adhesive sheet D2. The retardation laminate (C2) includes a PET film, a first retardation layer (first alignment layer, first liquid crystal layer), a second bonding layer (adhesive layer B), and a second retardation layer (second liquid crystal display). The layer, the second oriented layer), and the PET film were laminated in this order.

(Preparation of circularly polarizing plate (C2))
Fabrication of circularly polarizing plate (1) except that the pressure-sensitive adhesive sheet C prepared above was used instead of the pressure-sensitive adhesive sheet A and the retardation laminate (C2) was used instead of the retardation laminate (1). A circularly polarizing plate (C2) was obtained in the same procedure as in the above. The circular polarizing plate (C2) includes a polarizing plate (1) (TAC film, alignment layer, linearly polarized light layer (1), OC layer), a first bonding layer (adhesive layer C), a first retardation layer, and a first. The two bonding layers (adhesive layer B) and the second retardation layer were laminated in this order.

(Preparation of optical laminate (C2))
An optical laminate (C2) was obtained in the same procedure as in the production of the optical laminate (1) except that the circular polarizing plate (C2) was used instead of the circular polarizing plate (1). The optical laminate (C2) consisted of a front plate (HC layer, PI-based resin film), an adhesive layer A, a circularly polarizing plate (C2), an adhesive layer A, and a heavy SP film laminated in this order. .. The obtained optical laminate (C2) was used for evaluation of flexibility, measurement of ΔS, and visual evaluation. The results are shown in Table 1.

[Comparative Example 3]
(Preparation of phase difference laminate (C3))
A retardation laminate (C3) was obtained in the same procedure as in the production of the retardation laminate (2) except that the pressure-sensitive adhesive sheet D1 prepared above was used instead of the pressure-sensitive adhesive sheet D2. The retardation laminate (C3) includes a PET film, a first retardation layer (first alignment layer, first liquid crystal layer), a second bonding layer (adhesive layer D1), and a second retardation layer (second liquid crystal display). The layer, the second oriented layer), and the PET film were laminated in this order.

(Preparation of circularly polarizing plate (C3))
Fabrication of circularly polarizing plate (1) except that the pressure-sensitive adhesive sheet D2 prepared above was used instead of the pressure-sensitive adhesive sheet A and the retardation laminate (C3) was used instead of the retardation laminate (1). A circularly polarizing plate (C3) was obtained in the same procedure as in the above. The circular polarizing plate (C3) includes a polarizing plate (1) (TAC film, alignment layer, linearly polarized light layer (1), OC layer), a first bonding layer (adhesive layer D2), a first retardation layer, and a first. The two bonding layers (adhesive layer D1) and the second retardation layer were laminated in this order.

(Preparation of optical laminate (C3))
An optical laminate (C3) was obtained in the same procedure as in the production of the optical laminate (1) except that the circular polarizing plate (C3) was used instead of the circular polarizing plate (1). The optical laminate (C3) consisted of a front plate (HC layer, PI-based resin film), an adhesive layer A, a circularly polarizing plate (C3), an adhesive layer A, and a heavy SP film laminated in this order. .. Flexibility and visual evaluation were performed using the obtained optical laminate (C3). Since cracks were generated in the bending test, ΔS was not measured. The results are shown in Table 1.

[Comparative Example 4]
(Preparation of phase difference laminate (C4))
A retardation laminate (C4) was obtained in the same procedure as in the production of the retardation laminate (2) except that the pressure-sensitive adhesive sheet A prepared above was used instead of the pressure-sensitive adhesive sheet D2. The retardation laminate (C4) includes a PET film, a first retardation layer (first alignment layer, first liquid crystal layer), a second bonding layer (adhesive layer A), and a second retardation layer (second liquid crystal display). The layer, the second oriented layer), and the PET film were laminated in this order.

(Preparation of circularly polarizing plate (C4))
The surface of the retardation laminate (C4) exposed by peeling off the PET film on the first retardation layer side and the OC layer of the polarizing plate (1) prepared above are subjected to corona treatment (output 0.3 kW, treatment). The speed was 3 m / min). The adhesive composition prepared above was applied to the corona-treated surface on the first retardation layer side and bonded to the corona-treated surface of the polarizing plate (1). Using an ultraviolet irradiation device (ultraviolet lamp uses "H valve" manufactured by Fusion UV System Co., Ltd.), ultraviolet rays are emitted so that the light irradiation intensity is 400 mW / cm ² and the integrated light amount at wavelengths of 280 to 320 nm is 800 mJ / cm ^2. The adhesive composition was cured by irradiation to form an adhesive cured layer having a thickness of 2 μm as the first bonding layer, and a circular ultraviolet plate (C4) was obtained. The circular polarizing plate (C4) includes a polarizing plate (1) (TAC film, alignment layer, linearly polarized light layer (1), OC layer), a first bonding layer (adhesive curing layer), a first retardation layer, and a first. The two bonding layers (adhesive layer A) and the second retardation layer were laminated in this order.

(Preparation of optical laminate (C4))
An optical laminate (C4) was obtained in the same procedure as in the production of the optical laminate (1) except that the circular polarizing plate (C4) was used instead of the circular polarizing plate (1). The optical laminate (C4) consisted of a front plate (HC layer, PI-based resin film), an adhesive layer A, a circularly polarizing plate (C4), an adhesive layer A, and a heavy SP film laminated in this order. .. Flexibility and visual evaluation were performed using the obtained optical laminate (C4). Since cracks were generated in the bending test, ΔS was not measured. The results are shown in Table 1.

1 circularly polarizing plate, 5 optical laminate, 11 1st retardation layer, 12 2nd retardation layer, 21 1st bonding layer, 22 2nd bonding layer, 23 3rd bonding layer, 30 optical layer, 31 Linear polarizing layer, 32, 33 protective layer, 40 front plate, 100 test piece, 501,502 stage.

Claims

A circularly polarizing plate including at least an optical layer including a linearly polarized light layer, a first bonded layer, a first retarded layer, a second bonded layer, and a second retarded layer in this order.
The first retardation layer includes a first liquid crystal layer which is a cured product layer of a polymerizable liquid crystal compound.
The elastic moduli of the first bonding layer and the second bonding layer at a temperature of 25 ° C. are G'1 [kPa] and G'2 [kPa], respectively, and the first bonding layer and the second bonding layer are bonded. A circular polarizing plate satisfying the relationship of the following formula (1) when the thicknesses of the layers are d1 [μm] and d2 [μm], respectively.
G'1 / d1 <G'2 / d2 (1)
The thickness of the first retardation layer is t [μm], and the thickness is t [μm].
In the cross section of the bent portion of the circularly polarizing plate after the bending test, the position closest to the optical layer side and the farthest from the optical layer side of the surface of the first retardation layer on the first bonding layer side. The circularly polarizing plate according to claim 1, which satisfies the relationship of the following formula (2) when the distance in the thickness direction from the position is ΔS [μm].
ΔS ≦ 2t (2)
A circularly polarizing plate including at least an optical layer including a linearly polarized light layer, a first bonded layer, a first retarded layer, a second bonded layer, and a second retarded layer in this order.
The first retardation layer includes a first liquid crystal layer which is a cured product layer of a polymerizable liquid crystal compound.
The thickness of the first retardation layer is t [μm], and the thickness is t [μm].
In the cross section of the bent portion of the circularly polarizing plate after the bending test, the position closest to the optical layer side and the farthest from the optical layer side of the surface of the first retardation layer on the first bonding layer side. A circularly polarizing plate that satisfies the relationship of the following equation (2) when the distance from the position in the thickness direction is ΔS [μm].
ΔS ≦ 2t (2)
The circularly polarizing plate according to any one of claims 1 to 3, wherein the second retardation layer includes a second liquid crystal layer which is a cured product layer of a polymerizable liquid crystal compound.
The circularly polarizing plate according to any one of claims 1 to 4, wherein the thickness of the first retardation layer is 5 μm or less.
The circular polarizing plate according to any one of claims 1 to 5, wherein the linearly polarizing layer contains a cured product of a polymerizable liquid crystal compound and a dichroic dye.
The circular polarizing plate according to any one of claims 1 to 6, wherein the optical layer is a polarizing plate having a protective layer on one side or both sides of the linearly polarizing layer.
The first retardation layer and the second retardation layer are described in the following [a] or [b]:
[A] The first retardation layer is a 1/2 wavelength plate, and the second retardation layer is a 1/4 wavelength plate.
[B] One of the first retardation layer and the second retardation layer is a 1/4 wave plate having a reverse wavelength dispersion, and the other is a positive C plate.
The circularly polarizing plate according to any one of claims 1 to 7, which satisfies the above relationship.
The first retardation layer is a 1/4 wave plate having anti-wavelength dispersibility.
The circularly polarizing plate according to any one of claims 1 to 8, wherein the second retardation layer is a positive C plate.
The circularly polarizing plate according to any one of claims 1 to 9,
An optical laminate having a front plate laminated on the optical layer side of the circularly polarizing plate.
A display device including the optical laminate according to claim 10.