JP2022159116A - Laminate for display apparatus and display apparatus - Google Patents

Abstract

To provide a laminate for a display apparatus capable of improving visibility at a use form of observing an image in a state with the display apparatus bent.SOLUTION: A laminate for a display apparatus includes a substrate layer, a first layer and a second layer in this order. When light is incident onto a surface at the second layer side of the laminate for a display apparatus at an incidence angle 60°, a luminous reflectance of regular reflection light is 10.0% or less. An absolute value of a difference is 3.0 or less between yellowness YI1 of a transmitted beam in a 60° direction to a normal line of the surface at the second layer side of the laminate for a display apparatus and yellowness YI2 of a transmitted beam in a 15° direction to the normal line of the surface at the second layer side of the laminate for a display apparatus, in the laminate for the display apparatus.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present disclosure relates to a laminate for a display device and a display device using the same.

A laminate having functional layers having various properties such as hard coat properties, scratch resistance, antireflection properties, antiglare properties, antistatic properties, and antifouling properties is arranged on the surface of the display device.

Recently, flexible displays such as foldable displays, rollable displays, and bendable displays have attracted attention, and the development of laminates to be arranged on the surfaces of flexible displays is being actively pursued.

A flexible display is expected to be used, for example, to observe an image in a folded state. For example, FIG. 3 is a schematic cross-sectional view illustrating how the foldable display is used. As illustrated in FIG. 3 , in a mode of use in which an image is observed with the foldable display 20 folded, the foldable display 20 has a first display area 22 and a second display area 23 with the bent portion 21 as a boundary. will have In this case, the image or characters displayed in the second display area 23 may be reflected in the first display area 22, or the image or characters displayed in the first display area 22 may be reflected in the second display area 23. , there is a problem that the visibility of images and characters is lowered. This is not limited to foldable displays, and similar problems arise when viewing images in a flexible display in a folded state.

Further, in the display device, there is a problem that the color tone of the image changes depending on the viewing direction. In addition, as illustrated in FIG. 3, in a mode of use in which an image is observed with the foldable display 20 folded, the observer 25 moves only the line of sight without moving the observation position to display the first display area 22 and the second display area 22 . 2 tend to observe the image displayed in the display area 23 . In such a usage pattern, as illustrated in FIG. 3 , the position of the observer 25 is constant, so that the position of the observer 25 side of the foldable display 20 is different between the first display area 22 and the second display area 23 . The angle of the viewing direction with respect to the normal to the plane of . Therefore, there is a problem that the color tone of the image differs between the first display area 22 and the second display area 23 . This is not limited to foldable displays, and similar problems arise when viewing images in a flexible display in a folded state.

As a means for improving the visibility of a flexible display, for example, Patent Document 1 discloses a base film and the base film in order to solve the problem that visibility is reduced due to interference fringes caused by a hard coat film. wherein the base film is a polyimide film, and the refractive index of the polyimide film and the refractive index of the hard coat layer are The difference is an absolute value of 0.04 or less, the polyimide film has a thickness of 5 μm or more and 50 μm or less, and the hard coat layer has a thickness of 0.5 μm or more and 10 μm or less. A film is proposed.

Further, for example, in Patent Document 2, in a display device provided with an antireflection film, in order to solve the problem that the visually recognized color changes depending on the viewing angle, a transparent base film and the transparent base film and an antireflection layer formed on at least one of the antireflection film, wherein the luminosity reflectance for specular reflection at an incident angle of 5 ° of the antireflection film is 0.6% or less, and the incident angle of 5 ° The difference between the maximum and minimum values of the reflectance (%) in the wavelength range of 450 nm to 750 nm for specular reflection is 0.75 or less, and the reflectance (%) in the wavelength range of 400 nm to 700 nm for specular reflection at an incident angle of 45 ° Antireflection films have been proposed in which the difference between the maximum and minimum values of is 1.5 or less.

JP 2018-109773 A JP 2019-70756 A

However, Patent Literatures 1 and 2 do not consider the visibility in a usage pattern in which an image is observed while the display device is folded, and it is possible to improve the visibility in such a usage pattern. The actual situation is that no laminate has been proposed.

The present disclosure has been made in view of the above circumstances, and is primarily to provide a laminate for a display device capable of improving visibility in a usage pattern in which an image is observed while the display device is folded. aim.

One embodiment of the present disclosure is a laminate for a display device having a substrate layer, a first layer, and a second layer in this order, the surface of the laminate for a display device on the second layer side The luminous reflectance of specularly reflected light when light is incident on at an incident angle of 60 ° is 10.0% or less, and the normal to the second layer side surface of the display device laminate The absolute value of the difference between the yellowness YI1 of the transmitted light in the direction of 60° and the yellowness YI2 of the transmitted light in the direction of 15° with respect to the normal to the surface of the laminate for a display device on the second layer side is 3. 0.0 or less.

In the laminate for a display device according to the present disclosure, the second layer preferably has a thickness of 1 μm or more and 10 μm or less, and a refractive index of 1.40 or more and 1.50 or less.

In the laminate for a display device according to the present disclosure, the thickness of the second layer is 50 nm or more and 1 μm or less, and the ratio of the refractive index of the first layer to the refractive index of the second layer is 1.05 or more. It is also preferably 20 or less.

Further, in the laminate for a display device according to the present disclosure, the substrate layer may also serve as the first layer.

Further, the laminate for a display device in the present disclosure may have a hard coat layer between the base material layer and the first layer.

Further, the laminate for a display device in the present disclosure has a shock absorbing layer on the side of the substrate layer opposite to the first layer, or between the substrate layer and the first layer. good too.

Further, the laminate for a display device in the present disclosure may have an adhesive layer for attachment on the side of the substrate layer opposite to the first layer.

Another embodiment of the present disclosure provides a display device comprising a display panel and the above-described display device laminate disposed on the viewer side of the display panel.

In the present disclosure, it is possible to provide a laminate for a display device capable of improving visibility in a usage pattern in which an image is observed while the display device is folded.

1 is a schematic cross-sectional view illustrating a laminate for a display device according to the present disclosure; FIG. 1 is a schematic cross-sectional view illustrating a laminate for a display device according to the present disclosure; FIG. 1 is a schematic cross-sectional view illustrating a foldable display in the present disclosure; FIG. It is a schematic diagram explaining a dynamic bending test. 1 is a schematic cross-sectional view illustrating a laminate for a display device according to the present disclosure; FIG. 1 is a schematic cross-sectional view illustrating a laminate for a display device according to the present disclosure; FIG. 1 is a schematic cross-sectional view illustrating a laminate for a display device according to the present disclosure; FIG. 1 is a schematic cross-sectional view illustrating a laminate for a display device according to the present disclosure; FIG. 1 is a schematic cross-sectional view illustrating a display device according to the present disclosure; FIG.

Embodiments of the present disclosure will be described below with reference to the drawings and the like. However, the present disclosure can be embodied in many different modes and should not be construed as limited to the description of the embodiments exemplified below. In addition, in order to make the description clearer, the drawings may schematically show the width, thickness, shape, etc. of each part compared to the actual form, but this is only an example and limits the interpretation of the present disclosure. not something to do. In addition, in this specification and each figure, the same reference numerals may be given to the same elements as those described above with respect to the existing figures, and detailed description thereof may be omitted as appropriate.

In this specification, when expressing a mode of arranging another member on top of a certain member, when simply describing “above” or “below”, unless otherwise specified, 2 includes both cases in which another member is arranged directly above or directly below, and cases in which another member is arranged above or below a certain member via another member. In addition, in this specification, when expressing a mode in which another member is arranged on the surface of a certain member, when simply describing “on the surface side” or “on the surface”, unless otherwise specified, It includes both the case of arranging another member directly above or directly below so as to be in contact with it, and the case of arranging another member above or below a certain member via another member.

Hereinafter, the laminate for a display device and the display device according to the present disclosure will be described in detail.

A. Laminate for display device A laminate for a display device in the present disclosure is a laminate for a display device having a substrate layer, a first layer, and a second layer in this order, The luminous reflectance of specularly reflected light when light is incident on the second layer side surface at an incident angle of 60° is 10.0% or less, and the second layer side of the laminate for a display device has a luminous reflectance of 10.0% or less. Yellowness index YI1 of transmitted light in a direction of 60° with respect to the normal of the surface, and yellowness index YI2 of transmitted light in a direction of 15° with respect to the normal of the surface of the laminate for a display device on the second layer side. The absolute value of the difference between is 3.0 or less.

FIG. 1 is a schematic cross-sectional view showing an example of a laminate for a display device according to the present disclosure. As shown in FIG. 1, the display device laminate 1 has a substrate layer 2, a first layer 3, and a second layer 4 in this order. Further, as illustrated in FIG. 2A, the luminous reflectance of specularly reflected light L1 when light is incident on the surface S1 on the second layer side of the display device laminate 1 at an incident angle of 60° is It is less than or equal to a predetermined value. Further, as illustrated in FIG. 2A, the yellowness YI1 of the transmitted light L2 in the direction of 60° with respect to the normal to the surface S1 on the second layer side of the display device laminate 1 and the display device laminate The difference between the yellowness YI2 of the transmitted light L3 in the direction of 15° with respect to the normal to the surface S1 on the second layer side of the body 1 and the yellowness YI2 is a predetermined value or less.

Here, for example, in a foldable display, a usage pattern in which an image is observed in a folded state is assumed. In such a usage pattern, the foldable display 20 has a first display area 22 and a second display area 23 with the bent portion 21 as a boundary, as shown in FIG. 3, for example. In such a case, the image or characters displayed in the second display area 23 may be reflected in the first display area 22, or the image or characters displayed in the first display area 22 may be reflected in the second display area 23. As a result, there is a problem that the visibility of images and characters is lowered. This is not limited to foldable displays, and similar problems arise when viewing images in a flexible display in a folded state.

On the other hand, in the present disclosure, the luminous reflectance of the specularly reflected light L1 when light is incident on the surface S1 on the second layer side of the display device laminate 1 at an incident angle of 60° is a predetermined value or less. Therefore, when the laminate for a display device is used for a flexible display, when an image is observed with the flexible display folded, the image or characters displayed in one display area are displayed in the other display area. can be suppressed.

For example, in a foldable display, when an image is observed in a folded state, the angle θ2 formed by the first display area 22 and the second display area 23 as illustrated in FIG. From the viewpoint of , there is a tendency to set the angle larger than 90° and smaller than 180°, and specifically, it can be set to about 120°. When the display device laminate is arranged on the surface of the foldable display 20 on the viewer 25 side, the display device laminate 1 has the bent portion 11 as shown in FIG. 2B, for example. It has the first region 12 and the second region 13 as boundaries, and the angle θ1 formed by the first region 12 and the second region 13 is the same as the angle θ2 described above.

For example, in FIG. 2B, when light is incident on the surface S1 on the second layer side of the display device laminate 1 at an incident angle of 60°, the luminous reflectance of the specularly reflected light L1 is less than or equal to a predetermined value. 3, the light from the second display region 23 corresponding to the second region 13 of the display device laminate 1 is emitted from the first region of the display device laminate 1. Reflection in the first display area 22 corresponding to 12 can be suppressed. Therefore, in the case where the laminate for a display device of the present disclosure is used for a flexible display, when an image is observed with the flexible display folded, the image and characters displayed in one display area are different from those displayed in the other display area. It is possible to suppress reflection in the area.

In the present disclosure, when an image is observed with the foldable display 20 folded, for example, as shown in FIG. 3, the angle θ2 , from the viewpoint of visibility of displayed images and characters, tends to be set to be larger than 90 ° and smaller than 180 °, specifically, it can be set to about 120 °; When observing an image with the bull display 20 folded, the observer 25 tends to observe the images displayed in the first display area 22 and the second display area 23 by moving only the line of sight without moving the observation position. and that even on the same surface, the higher the incident angle, the higher the reflectance. The luminous reflectance of specularly reflected light at an incident angle of 60° is the visual sensation when light from one display area is reflected by the other display area when an image is observed with the flexible display folded. shall represent the reflectance.

Further, in the display device, there is a problem that the color tone of the image changes depending on the viewing direction. In addition, as described above, when observing an image with the foldable display folded, the observer moves only the line of sight without moving the observation position, and the image is displayed in the first display area and the second display area. I tend to look at images. In such a case, as illustrated in FIG. 3, the position of the observer 25 is constant, so the first display area 22 and the second display area 23 are different from each other on the observer 25 side of the foldable display 20. The angle of the viewing direction with respect to the surface normal will be different. Therefore, there is a problem that the color tone of the image differs between the first display area 22 and the second display area 23 . This is not limited to foldable displays, and similar problems arise when viewing images in a flexible display in a folded state.

On the other hand, in the present disclosure, the yellowness YI1 of the transmitted light in the direction of 60° with respect to the normal to the surface of the second layer side of the laminate for display device, and the yellowness degree YI1 of the second layer side of the laminate for display device The absolute value of the difference between the yellowness YI2 of the transmitted light in the direction of 15° with respect to the normal of the surface is less than or equal to a predetermined value, so that when the laminate for a display device is used for a flexible display, the flexible display When an image is observed in a folded state, the difference in color between one display area and the other display area can be reduced, and color change can be suppressed.

For example, in FIG. 2B, the yellowness YI1 of the transmitted light L2 in the direction of 60° with respect to the normal to the surface S1 on the second layer side of the display device laminate 1 and the second If the absolute value of the difference between the yellowness YI2 of the transmitted light L3 in the direction of 15° with respect to the normal to the surface S1 on the layer side and the yellowness YI2 is equal to or less than a predetermined value, the foldable display 20 illustrated in FIG. The difference in color of the image between the first display region 22 corresponding to the first region 12 of the display device laminate 1 and the second display region 23 corresponding to the second region 13 of the display device laminate 1 is determined. It can be made small, and color change can be suppressed. Therefore, when the laminate for a display device of the present disclosure is used for a flexible display, when the image is observed with the flexible display folded, the color of the image in one display area and the other display area Change can be suppressed.

In the present disclosure, when an image is observed with the foldable display 20 folded, for example, as shown in FIG. 3, the angle θ2 tends to be set to be larger than 90° and smaller than 180° from the viewpoint of visibility of displayed images and characters, and can be specifically set to about 120°; When observing an image with the foldable display 20 folded, the observer 25 observes the images displayed in the first display area 22 and the second display area 23 by moving only the line of sight without moving the observation position. In such a case, the range of viewing directions is limited; and so on, the yellowness of the transmitted light in the 60° direction and the yellowness of the transmitted light in the 15° direction were adopted. The yellowness of the transmitted light in the direction of 60 ° and the yellowness of the transmitted light in the direction of 15 ° are respectively the color of the image in one display area and the display of the other when the image is observed with the flexible display folded. It represents the color tone of the image in the area.

In addition, in the present disclosure, the yellowness index is adopted in consideration of the change in color tone of a white image. A yellowness value closer to zero indicates whiter, a negative yellowness value indicates bluer, and a positive yellowness indicates yellower.

In FIG. 3, L21 indicates the light emitted from the second display area 23 and reflected by the first display area 22, and L22 indicates the normal line of the surface of the foldable display 20 on the observer 25 side. , and L23 indicates light in a direction of 15° with respect to the normal to the surface of the foldable display 20 on the viewer 25 side.

Therefore, when the laminate for a display device according to the present disclosure is used for a display device, especially a flexible display, it is possible to improve visibility in a usage pattern in which an image is observed while the display device is folded.

Each configuration of the laminate for a display device according to the present disclosure will be described below.

1. Characteristics of Laminate for Display Device In the present disclosure, the luminous reflectance of specularly reflected light when light is incident on the second layer side surface of the laminate for display device at an incident angle of 60° is 10.0%. or less, preferably 9.5% or less, more preferably 9.0% or less. When the luminous reflectance of specularly reflected light at the incident angle of 60° is within the above range, when the laminate for a display device of the present disclosure is used for a flexible display, an image can be obtained when the flexible display is folded. , it is possible to prevent images and characters displayed in one display area from being reflected in the other display area. The lower the luminous reflectance of specularly reflected light at the incident angle of 60° is, the better. The luminous reflectance of specularly reflected light at the incident angle of 60° is preferably 0.1% or more and 10.0% or less, more preferably 0.5% or more and 9.5% or less. It is preferably 1.0% or more and 9.0% or less, more preferably.

Further, the luminous reflectance of specularly reflected light when light is incident on the second layer side surface of the display device laminate at an incident angle of 5° is, for example, 0.1% or more and 4.0% or less. preferably 0.5% or more and 3.5% or less, and even more preferably 1.0% or more and 3.0% or less. When the luminous reflectance of specularly reflected light at the incident angle of 5° is within the above range, the laminate for a display device of the present disclosure is not folded, that is, the angle θ2 is 180° in FIG. When viewing an image in a state, it reduces the color difference between one display area and the other display area while suppressing the viewer's own reflection in the display area. can be suppressed.

Here, the luminous reflectance can be determined according to JIS Z8722:2009. The luminous reflectance is obtained from the reflection spectrum obtained by making light in the wavelength range of 380 nm or more and 780 nm or less incident on the second layer side surface of the laminate for a display device, in a 2 degree field of view with standard light C. , and the tristimulus values X, Y, and Z in the XYZ color system are obtained, and the value of Y is the luminous reflectance.
That is, the luminous reflectance refers to the Y value of the CIE1931 standard color system. In the measurement of luminous reflectance, the following conditions can be used.

(Measurement condition)
・Field of view: 2°
・Illuminant: C
・Light source: tungsten halogen lamp ・Measurement wavelength: 0.5 nm interval in the range of 380 nm to 780 nm ・Scan speed: high speed ・Slit width: 5.0 nm
・S/R switching: Standard ・Auto zero: Performed at 550 nm after baseline scanning

In addition, when measuring the luminous reflectance of the laminate for a display device, a black vinyl tape having a width larger than the measurement spot area (for example, product name "Yamato vinyl tape NO200-19-21 , Yamato Co., Ltd., 19 mm width) is attached to the surface of the laminate for display device on the side of the substrate layer, and then the measurement is performed. As a device for measuring luminous reflectance, for example, a spectrophotometer can be used. Specifically, a spectrophotometer “UV-2600” manufactured by Shimadzu Corporation can be used. The angle of incidence refers to the angle of light incident on the second layer side surface of the display device laminate with respect to the normal to the second layer side surface of the display device laminate.

In order to reduce the luminous reflectance of specularly reflected light when light is incident on the second layer side surface of the display device laminate at an incident angle of 60°, for example, (1-1) the second layer (1-2) making the ratio of the refractive index of the first layer to the refractive index of the second layer close to 1;

(1-1) When the refractive index of the second layer is relatively low, the difference between the refractive index of the second layer and the refractive index of air is It is possible to reduce the reflection of light on the surface of the display device laminate on the second layer side, and to reduce the luminous reflectance of specularly reflected light at the incident angle of 60°. . In this case, it is preferable to make the thickness of the second layer relatively thick. Since the thickness of the second layer is relatively thick, interference between specularly reflected light from the interface between the first layer and the second layer and specularly reflected light from the surface on the second layer side is less likely to occur. Reflection of light on the second layer side surface of the body can be effectively suppressed. As a method for making the refractive index of the second layer relatively low, for example, the second layer contains resin and low refractive index particles having a lower refractive index than the resin, or the second layer contains a low refractive index particle having a low refractive index. A method of including a refractive index resin can be used.

(1-2) When the ratio of the refractive index of the first layer to the refractive index of the second layer is close to 1, the ratio of the refractive index of the first layer to the refractive index of the second layer is close to 1, the reflection of light at the interface between the first layer and the second layer can be suppressed, and the luminous reflectance of specularly reflected light at the incident angle of 60° can be reduced. can. In this case, it is preferable to make the thickness of the second layer relatively thin. When the thickness of the second layer is relatively thin, by adjusting the refractive index and thickness of the second layer, the interference of light by the thin film is controlled, and the regular reflection light at the incident angle of 60 ° luminous reflectance can be controlled. As a method of making the ratio of the refractive index of the first layer to the refractive index of the second layer close to 1, for example, a method of adjusting the refractive indices of the first layer and the second layer can be mentioned.

Specific means for reducing the luminous reflectance of specularly reflected light at the incident angle of 60° will be described later in the sections on the first layer and the second layer.

Further, in the present disclosure, the yellowness YI1 of the transmitted light in the direction of 60° with respect to the normal to the surface of the second layer side of the laminate for display device and the normal of the surface of the second layer side of the laminate for display device The absolute value of the difference from the yellowness YI2 of the transmitted light in the direction of 15° to the line is 3.0 or less, preferably 2.5 or less, more preferably 2.0 or less. When the absolute value of the difference between the yellowness indices YI1 and YI2 is within the above range, when the laminate for a display device of the present disclosure is used for a flexible display, when an image is observed with the flexible display folded, can suppress the color change of an image between one display area and the other display area.
Also, the absolute value of the difference between the yellowness indices YI1 and YI2 is preferably as small as possible, and the lower limit is not particularly limited, but can be, for example, 0.0 or more. The absolute value of the difference between the yellowness indices YI1 and YI2 is preferably 0.0 or more and 3.0 or less, more preferably 0.2 or more and 2.5 or less, and 0.5 or more and 2.0 More preferably:

Here, the yellowness index (YI) can be determined according to JIS K7373:2006. Specifically, using an ultraviolet-visible-near-infrared spectrophotometer, the transmittance is measured at intervals of 0.5 nm in the range of 300 nm or more and 780 nm or less using a deuterium lamp and a tungsten halogen lamp by a spectrophotometric method. Based on this, the tristimulus values X, Y, and Z in the XYZ color system are obtained in the 2-degree field of view with standard light C, and the values of X, Y, and Z can be calculated from the following formula. .
YI=100(1.2769X−1.0592Z)/Y

In the measurement of the yellowness index (YI), the following conditions can be used.
(Measurement condition)
・Field of view: 2°
・Illuminant: C
・Light source: deuterium lamp and tungsten halogen lamp ・Measurement wavelength: 0.5 nm interval in the range of 300 nm to 780 nm ・Scan speed: high speed ・Slit width: 5.0 nm
・S/R switching: Standard ・Auto zero: Performed at 550 nm after baseline scanning

As the ultraviolet-visible-near-infrared spectrophotometer, for example, "V-7100" manufactured by JASCO Corporation can be used.

In order to reduce the absolute value of the difference between the yellowness indices YI1 and YI2, for example, (2-1) make the ratio of the refractive index of the first layer to the refractive index of the second layer close to 1; (2-2) Making the haze of the second layer relatively low.

(2-1) When the ratio of the refractive index of the first layer to the refractive index of the second layer is set to be close to 1, the ratio of the refractive index of the first layer to the refractive index of the second layer is By being close to 1, reflection of light at the interface between the first layer and the second layer can be suppressed, and generation of interference fringes due to transmitted light can be suppressed. As a result, the change in transmittance due to the change in the angle of transmitted light can be reduced, and the absolute value of the difference between the yellownesses YI1 and YI2 can be reduced. On the other hand, when the ratio of the refractive index of the first layer to the refractive index of the second layer is large, interference fringes are generated by transmitted light. The occurrence of interference fringes may affect the transmission spectrum and increase the change in transmittance due to the change in the angle of transmitted light. As a result, the absolute value of the difference between the yellownesses YI1 and YI2 becomes large. Also, when the ratio of the refractive index of the first layer to the refractive index of the second layer is to be close to 1, it is preferable to make the thickness of the second layer relatively thin. When the thickness of the second layer is relatively thin, by adjusting the refractive index and thickness of the second layer, it is possible to control the interference of light by the thin film and suppress the generation of interference fringes due to transmitted light. can.

In addition, in the case of (2-2) making the haze of the second layer relatively low, the yellowness YI1 and YI2 tend to decrease as the haze of the second layer decreases. The absolute value of the difference between YI1 and YI2 can be reduced. On the other hand, when the haze of the second layer increases, the yellowness indices YI1 and YI2 tend to increase, and the absolute value of the difference between the yellowness indices YI1 and YI2 may increase. As a method for controlling the haze of the second layer, for example, when the second layer contains a resin and low refractive index particles having a lower refractive index than the resin, the content of the low refractive index particles is adjusted. method.

Specific means for reducing the absolute value of the difference between the yellowness indices YI1 and YI2 will be described later in the sections on the first layer and the second layer.

The laminate for a display device in the present disclosure preferably has a total light transmittance of, for example, 85% or more, more preferably 88% or more, and even more preferably 90% or more. Due to such a high total light transmittance, a laminate for a display device with good transparency can be obtained.

Here, the total light transmittance of the laminate for a display device can be measured according to JIS K7361-1:1999, for example, by a haze meter HM150 manufactured by Murakami Color Research Laboratory.

The haze of the laminate for a display device in the present disclosure is, for example, preferably 5% or less, more preferably 2% or less, and even more preferably 1% or less. Such a low haze makes it possible to obtain a laminate for a display device with good transparency.

Here, the haze of the laminate for a display device can be measured according to JIS K-7136:2000, for example, by a haze meter HM150 manufactured by Murakami Color Research Laboratory.

The laminate for a display device in the present disclosure preferably has bending resistance. Specifically, when the display device laminate is subjected to a dynamic bending test described below, it is preferable that the display device laminate does not crack or break.

A dynamic bending test is performed as follows. First, a display device laminate having a size of 50 mm×200 mm is prepared. In the dynamic bending test, as shown in FIG. 4A, the short side portion 1C of the display device laminate 1 and the short side portion 1D facing the short side portion 1C are arranged in parallel. are fixed by the fixing portion 51. As shown in FIG. Further, as shown in FIG. 4(a), the fixed portion 51 is horizontally slidable. Next, as shown in FIG. 4(b), the fixed portions 51 are moved closer to each other, thereby deforming the laminate for display device 1 so as to be folded, and furthermore, as shown in FIG. 4(c), Then, after moving the fixing portion 51 to a position where the distance d between the two opposing short side portions 1C and 1D fixed by the fixing portion 51 of the display device laminate 1 becomes a predetermined value, the fixing portion 51 is removed. Deformation of the display device laminate 1 is eliminated by moving in the opposite direction. By moving the fixing portion 51 as shown in FIGS. 4A to 4C, the display device laminate 1 can be folded 180°. In addition, a dynamic bending test was performed so that the bent portion 1E of the laminated body 1 for a display device did not protrude from the lower end of the fixed portion 51, and by controlling the distance when the fixed portion 51 was closest, the display device The distance d between the two opposing short sides 1C and 1D of the laminate 1 can be set to a predetermined value. For example, when the interval d between the short sides 1C and 1D is 30 mm, the outer diameter of the bent portion 1E is considered to be 30 mm. For the dynamic bending test, for example, an endurance tester (product name “DLDMLH-FS”, manufactured by Yuasa System Co., Ltd.) can be used.

In the display device laminate, a dynamic bending test in which the display device laminate 1 is folded 180° so that the distance d between the opposing short side portions 1C and 1D is 30 mm is repeated 200,000 times, and cracking occurs. Alternatively, it is preferable that no breakage occurs, and more preferably, no cracking or breakage occurs when repeated 500,000 times. Above all, it is preferable that no cracks or breaks occur when a dynamic bending test is repeated 200,000 times in which the display device laminate is folded 180° so that the distance d between the opposing short sides 1C and 1D is 20 mm. In particular, no cracking or breakage occurs when a dynamic bending test is repeated 200,000 times in which the laminate for display device 1 is folded 180° so that the distance d between the opposing short sides 1C and 1D is 10 mm. is preferred.

In the dynamic bending test, the display laminate may be folded so that the second layer is on the outside, or the display laminate may be folded so that the second layer is on the inside, in either case. Even so, it is preferable that the display device laminate does not crack or break.

2. First Layer and Second Layer In the present disclosure, the first layer and the second layer are arranged in this order on one side of the substrate layer.

In the present disclosure, in order to make the luminous reflectance of specularly reflected light at the incident angle of 60° equal to or less than a predetermined value and to make the absolute value of the difference between the yellownesses YI1 and YI2 equal to or less than a predetermined value, , as described above, the refractive index of the second layer is relatively low, the refractive index of the second layer is within a predetermined range, and the thickness of the second layer is relatively thick; Preferably, the ratio of the refractive index of the first layer to the index is relatively small and the thickness of the second layer is relatively thin. Specifically, the refractive index of the second layer is 1.40 or more and 1.50 or less, and the thickness of the second layer is 1 μm or more and 10 μm or less, or is preferably 1.05 or more and 1.20 or less, and the thickness of the second layer is 50 nm or more and 1 μm or less. These two preferred embodiments will be described separately below.

(1) First Embodiment In this embodiment, the second layer has a refractive index of 1.40 or more and 1.50 or less, and a thickness of 1 μm or more and 10 μm or less.

In this embodiment, since the refractive index of the second layer is within a predetermined range, the difference between the refractive index of the air and the refractive index of the second layer can be reduced. Reflection of light can be suppressed. In addition, since the thickness of the second layer is a predetermined value or more and is relatively thick, interference between specularly reflected light from the interface between the first and second layers and specularly reflected light from the surface on the second layer side This makes it possible to effectively suppress the reflection of light on the second layer side surface of the laminate for a display device.
Therefore, the luminous reflectance of specularly reflected light at the incident angle of 60° can be reduced.

Here, the first layer is usually a layer containing a resin, and a typical resin has a refractive index of about 1.5. As will be described later, when the substrate layer also serves as the first layer, for example, a resin substrate or a glass substrate can be used as the substrate layer. It is about 0.5, and the refractive index of general glass is also about 1.5.

In this embodiment, since the refractive index of the second layer is within a predetermined range, the ratio of the refractive index of the first layer to the refractive index of the second layer can be made close to 1. As described above, the absolute value of the difference between the yellownesses YI1 and YI2 can be reduced.

In addition, in this embodiment, the thickness of the second layer is equal to or less than a predetermined value, so that flexibility and bending resistance can be enhanced.

(a) Second layer (i) Properties of the second layer In this embodiment, the refractive index of the second layer is, for example, preferably 1.40 or more, more preferably 1.43 or more, It is more preferably 1.45 or more.
When the refractive index of the second layer is within the above range, the ratio of the refractive index of the first layer to the refractive index of the second layer can be made close to 1, and the difference between the yellowness indices YI1 and YI2 can reduce the absolute value of Also, the refractive index of the second layer is, for example, preferably 1.50 or less, more preferably 1.49 or less, and even more preferably 1.48 or less. When the refractive index of the second layer is within the above range, the difference from the refractive index of air can be reduced, and the reflection of light on the second layer side surface of the display device laminate can be suppressed. can. The refractive index of the second layer is preferably 1.40 or more and 1.50 or less, more preferably 1.43 or more and 1.49 or less, and further preferably 1.45 or more and 1.48 or less. preferable.

Further, in this embodiment, the ratio of the refractive index of the first layer to the refractive index of the second layer is, for example, preferably 1.00 or more and 1.18 or less, and is 1.01 or more and 1.15 or less. is more preferable, and more preferably 1.02 or more and 1.10 or less. By making the ratio of the refractive index of the first layer to the refractive index of the second layer close to 1, the luminous reflectance of specularly reflected light at the incident angle of 60° can be reduced, and the above It is possible to reduce the absolute value of the difference between the yellownesses YI1 and YI2. Further, by setting the ratio of the refractive index of the first layer to the refractive index of the second layer within the above range, it is possible to improve the visibility of the flexible display while enhancing flexibility and bending resistance.

Here, the refractive index of each layer refers to the refractive index for light with a wavelength of 550 nm. A method of measuring the refractive index can include a method of measuring using an ellipsometer. Examples of the ellipsometer include "UVSEL" manufactured by Jobin-Evon and "DF1030R" manufactured by Techno Synergy. The same applies to the methods for measuring the refractive indices of the first layer and the base material layer.

In this embodiment, the thickness of the second layer is, for example, preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more. When the thickness of the second layer is within the above range, interference between specularly reflected light from the interface between the first and second layers and specularly reflected light from the surface on the second layer side is less likely to occur. Reflection of light on the second layer side surface of the body can be effectively suppressed. Also, the thickness of the second layer is, for example, preferably 10 μm or less, more preferably 9 μm or less, and even more preferably 8 μm or less. If the thickness of the second layer is too thick, the flexibility and bending resistance may be impaired. The thickness of the second layer is preferably 1 μm or more and 10 μm or less, more preferably 3 μm or more and 9 μm or less, and even more preferably 5 μm or more and 8 μm or less.

Here, the thickness of the second layer is the cross section in the thickness direction of the display device laminate observed with a transmission electron microscope (TEM), a scanning electron microscope (SEM), or a scanning transmission electron microscope (STEM). , and can be the average value of 10 randomly selected thicknesses. The thickness of other layers included in the display device laminate can be measured in the same manner.

(ii) Material for Second Layer The material for the second layer is not particularly limited as long as it is a material capable of obtaining the second layer that satisfies the above refractive index. The second layer may contain, for example, a resin and low refractive index particles having a lower refractive index than the resin, or may contain a low refractive index resin having the above refractive index.

(ii-1) Resin and low refractive index particles When the second layer contains a resin and low refractive index particles, the low refractive index particles have a refractive index lower than that of the resin. There is no particular limitation as long as it is possible to obtain a second layer that satisfies the refractive index.

The low refractive index particles may be either inorganic particles or organic particles. Examples of inorganic particles include inorganic particles such as silicon dioxide (silica), magnesium fluoride, lithium fluoride, calcium fluoride, and barium fluoride. Among them, silica particles are preferred.

The low refractive index particles may be, for example, solid particles, hollow particles, or porous particles. Among them, hollow particles and porous particles are preferable because of their low refractive index. Examples of hollow particles and porous particles include porous silica particles, hollow silica particles, porous polymer particles, hollow polymer particles and the like.

Also, the low refractive index particles may be surface-treated. By subjecting the low refractive index particles to a surface treatment, the affinity with resins and solvents is improved, the low refractive index particles are uniformly dispersed, and aggregation of the low refractive index particles is less likely to occur. It is possible to suppress the decrease in transparency, the coatability of the resin composition for the second layer, and the decrease in film strength.

Examples of the surface treatment method include surface treatment using a silane coupling agent. A specific silane coupling agent may be the same as the silane coupling agent disclosed in JP-A-2013-142817, for example.

Also, the low refractive index particles may be reactive particles having a polymerizable functional group on their surface.
Examples of the low refractive index particles that are reactive particles include those used in the low refractive index layer described in JP-A-2013-142817.

The average particle size of the low refractive index particles may be equal to or less than the thickness of the second layer, and may be, for example, 300 nm or less, may be 200 nm or less, may be 150 nm or less, or may be 100 nm or less. may The average particle size of the low refractive index particles is, for example, 5 nm or more, may be 10 nm or more, may be 30 nm or more, or may be 50 nm or more. If the average particle size of the low refractive index particles is within the above range, the low refractive index particles can be dispersed well without impairing the transparency of the second layer. As long as the average particle size of the low refractive index particles is within the above range, the average particle size may be either the primary particle size or the secondary particle size. good too. The average particle diameter of the low refractive index particles is, for example, preferably 5 nm or more and 300 nm or less, more preferably 10 nm or more and 200 nm or less, further preferably 30 nm or more and 150 nm or less, and 50 nm or more and 100 nm or less. is most preferred.

Here, the average particle size of the low refractive index particles refers to the average value of 20 particles observed in a transmission electron microscope (TEM) photograph of the cross section of the second layer.

The shape of the low refractive index particles is not particularly limited, and may be, for example, spherical, chain-like, needle-like, and the like.

When the second layer contains a resin and low refractive index particles, the resin is appropriately selected from the viewpoint of film-forming properties, film strength, and the like. Among them, the resin is preferably a cured resin cured by heat or irradiation with ionizing radiation such as ultraviolet rays or electron beams. Examples of curable resins include thermosetting resins and ionizing radiation curable resins. Further, examples of the ionizing radiation curable resin include ultraviolet curable resin and electron beam curable resin. Among them, an ionizing radiation curable resin is preferable. This is because the surface hardness of the second layer can be increased.

As used herein, the term "ionizing radiation-cured resin" refers to a resin cured by irradiation with ionizing radiation. In addition, "ionizing radiation" refers to electromagnetic waves or charged particle beams that have energy quanta capable of polymerizing or cross-linking molecules. Examples include charged particle beams such as α rays and ion beams.

Examples of ionizing radiation curable resins include compounds having one or more unsaturated bonds, such as compounds having acrylate-based functional groups. Examples of compounds having one unsaturated bond include ethyl (meth)acrylate, ethylhexyl (meth)acrylate, styrene, methylstyrene, N-vinylpyrrolidone and the like. Compounds having two or more unsaturated bonds include, for example, polymethylolpropane tri(meth)acrylate, hexanediol (meth)acrylate, tripropylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, pentaerythritol tri Polyfunctional compounds such as (meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentylglycol di(meth)acrylate, and the polyfunctional compound and (meth) Examples thereof include reaction products with acrylates and the like (for example, poly(meth)acrylate esters of polyhydric alcohols). "(Meth)acrylate" refers to methacrylate and acrylate.

As the ionizing radiation curable resin, a relatively low molecular weight polyester resin having an unsaturated double bond, a polyether resin, an acrylic resin, an epoxy resin, a urethane resin, an alkyd resin, a spiroacetal resin, a polybutadiene resin, and a polythiol polyene resin. etc. can also be used. Furthermore, as the resin, a low refractive index resin, which will be described later, may be used.

The contents of the resin and the low refractive index particles in the second layer are appropriately set so that the refractive index of the second layer as a whole satisfies the above refractive index. In the second layer, the content of the low refractive index particles is, for example, preferably 10 parts by mass or more and 300 parts by mass or less, and preferably 30 parts by mass or more and 250 parts by mass or less with respect to 100 parts by mass of the resin. More preferably, it is 50 parts by mass or more and 200 parts by mass or less. If the content of the low refractive index particles is too low, the desired refractive index may not be obtained. Further, if the content of the low refractive index particles is too large, the haze of the second layer will increase, the yellowness Y1 and Y2 will increase, and the absolute value of the difference between the yellowness Y1 and Y2 may increase. There is

(ii-2) Low refractive index resin When the second layer contains a low refractive index resin, the second layer composed of the low refractive index resin can satisfy the above refractive index. Any resin may be used as long as it is a suitable resin, and examples thereof include fluorine resins, silicone resins, acrylic resins, and olefin resins.

(ii-3) Additives The second layer may contain a photopolymerization initiator when an ultraviolet curable resin is used as the resin. In addition, the second layer may contain various additives according to desired physical properties. Additives include, for example, ultraviolet absorbers, antioxidants, light stabilizers, infrared absorbers, dispersing aids, weather resistance improvers, wear resistance improvers, antistatic agents, polymerization inhibitors, cross-linking agents, adhesion property improvers, leveling agents, thixotropic agents, coupling agents, plasticizers, antifoaming agents, fillers and the like.

(iii) Method for Forming Second Layer Examples of the method for forming the second layer include a method in which the resin composition for the second layer is applied onto the first layer and cured.

(b) First layer (i) Characteristics of first layer In this embodiment, the ratio of the refractive index of the first layer to the refractive index of the second layer is preferably within a predetermined range as described above. . Note that the ratio of the refractive index of the first layer to the refractive index of the second layer will be described later in the second embodiment, so the description is omitted here.

The refractive index of the first layer is not particularly limited as long as it satisfies the ratio of the refractive index of the first layer to the refractive index of the second layer, and is, for example, 1.50 or more and 1.65 or less. , more preferably 1.52 or more and 1.63 or less, and even more preferably 1.54 or more and 1.60 or less. Usually, the refractive index of the first layer is higher than the refractive index of the second layer, and the refractive index of the first layer is within the above range. It can be made close to 1, and the absolute value of the difference between the yellowness degrees YI1 and YI2 can be reduced. When the refractive index of the first layer is within the above range, the difference from the refractive index of the base layer can be reduced, and the reflection of light at the interface between the first layer and the base layer can be suppressed. can.

The thickness of the first layer is, for example, preferably 1 μm or more and 20 μm or less, more preferably 3 μm or more and 15 μm or less, and even more preferably 5 μm or more and 10 μm or less. When the thickness of the first layer is within the above range, both flexibility and bending resistance can be achieved. Moreover, when the thickness of the first layer is too thick, there is a possibility that flexibility and bending resistance may be impaired.

As described later, the substrate layer may also serve as the first layer, but the thickness of the first layer is the thickness of the first layer when the substrate layer does not serve as the first layer. It is.

(ii) Material for the First Layer The material for the first layer is not particularly limited as long as it is a material capable of obtaining the first layer that satisfies the above refractive index. The first layer can contain a resin. The resin is preferably a curable resin that is cured by heat or irradiation with ionizing radiation such as ultraviolet rays or electron beams. The cured resin may be the same as the cured resin used for the second layer. Among them, ionizing radiation curable resins are preferable from the viewpoint of scratch resistance. This is because the surface hardness of the low refractive index layer can be increased.

The first layer may contain a photopolymerization initiator when an ultraviolet curable resin is used as the resin. In addition, the first layer may contain various additives according to desired physical properties. Additives may be the same as those used in the second layer.

(iii) Method for Forming First Layer Examples of the method for forming the first layer include a method in which the resin composition for the first layer is applied onto the substrate layer and cured.

(2) Second Embodiment In this embodiment, the ratio of the refractive index of the first layer to the refractive index of the second layer is 1.05 or more and 1.20 or less, and the thickness of the second layer is 50 nm or more and 1 μm. It is below.

In this embodiment, since the ratio of the refractive index of the first layer to the refractive index of the second layer is within a predetermined range, reflection of light at the interface between the first layer and the second layer can be suppressed. can. In addition, since the thickness of the second layer is within a predetermined range and is relatively thin, it is possible to control the interference of light by the thin film by adjusting the refractive index and thickness of the second layer. Therefore, the luminous reflectance of specularly reflected light at the incident angle of 60° can be reduced. Furthermore, the generation of interference fringes due to transmitted light can be suppressed, and the change in transmittance due to the change in the angle of transmitted light can be reduced. Therefore, the absolute value of the difference between the yellownesses YI1 and YI2 can be reduced.

In addition, in this embodiment, the thickness of the second layer is within a predetermined range, so flexibility and bending resistance can be enhanced.

(a) Second layer (i) Characteristics of second layer In this embodiment, the ratio of the refractive index of the first layer to the refractive index of the second layer is, for example, 1.05 or more and 1.20 or less. It is preferably 1.07 or more and 1.18 or less, and further preferably 1.09 or more and 1.15 or less. By making the ratio of the refractive index of the first layer to the refractive index of the second layer close to 1, the luminous reflectance of specularly reflected light at the incident angle of 60° can be reduced, and the above It is possible to reduce the absolute value of the difference between the yellownesses YI1 and YI2. Further, by setting the ratio of the refractive index of the first layer to the refractive index of the second layer within the above range, it is possible to improve the visibility of the flexible display while enhancing flexibility and bending resistance.

The refractive index of the second layer is not particularly limited as long as the ratio of the refractive index of the first layer to the refractive index of the second layer is satisfied. It is more preferably 1.42 or more, and even more preferably 1.44 or more. This is because, if the refractive index of the second layer is within the above range, it is easy to adjust the ratio of the refractive index of the first layer to the refractive index of the second layer so as to be within a predetermined range. Also, the refractive index of the second layer is, for example, preferably 1.50 or less, more preferably 1.49 or less, and even more preferably 1.48 or less. When the refractive index of the second layer is within the above range, the difference from the refractive index of air can be reduced, and the reflection of light on the second layer side surface of the display device laminate can be suppressed. can. The refractive index of the second layer is, for example, preferably 1.40 or more and 1.50 or less, more preferably 1.42 or more and 1.49 or less, and 1.44 or more and 1.48 or less. is more preferred.

In this embodiment, the thickness of the second layer is appropriately adjusted according to the refractive index of the second layer. For example, the thickness of the second layer is preferably 50 nm or more, more preferably 60 nm or more, and even more preferably 70 nm or more. If the thickness of the second layer is too thin, the film strength may decrease. Also, the thickness of the second layer is, for example, preferably 1 μm or less, more preferably 700 nm or less, and even more preferably 500 nm or less. When the thickness of the second layer is within the above range, it is possible to suppress the reflection and the occurrence of interference fringes due to transmitted light by utilizing the light interference effect of the thin film. The thickness of the second layer is, for example, preferably 50 nm or more and 1 μm or less, more preferably 60 nm or more and 700 nm or less, and even more preferably 70 nm or more and 500 nm or less.

(ii) Material for Second Layer The material for the second layer is not particularly limited as long as it is a material capable of obtaining the second layer that satisfies the above refractive index and thickness. The second layer, for example, contains a resin and low refractive index particles having a lower refractive index than the resin, or contains a low refractive index resin having the above refractive index, or has the above refractive index A low refractive index inorganic material can be included.

When the second layer contains resin and low refractive index particles, the resin and low refractive index particles can be the same as in the first embodiment.

When the second layer contains a low refractive index resin, the low refractive index resin can be the same as in the first embodiment.

Further, when the second layer contains a low refractive index inorganic material, the low refractive index inorganic material is an inorganic material that allows the second layer composed of the low refractive index inorganic material to satisfy the above refractive index. Any material may be used, and examples thereof include silicon dioxide (silica), magnesium fluoride, lithium fluoride, calcium fluoride, and barium fluoride. Among them, silicon dioxide (silica) is preferred.

The second layer may contain a photopolymerization initiator when an ultraviolet curable resin is used as the resin. In addition, the second layer may contain various additives according to desired physical properties. Additives may be the same as in the first embodiment.

(iii) Method for Forming Second Layer The method for forming the second layer is appropriately selected according to the material of the second layer. When the second layer contains a resin and low refractive index particles, and when the second layer contains a low refractive index resin, the second layer may be formed by, for example, forming a second layer on the first layer. A method of applying a two-layer resin composition and curing it may be mentioned. Further, when the second layer contains a low refractive index inorganic material, examples of the method for forming the second layer include a vacuum deposition method and a sputtering method.

(b) First layer (i) Characteristics of first layer The refractive index of the first layer is not particularly limited as long as it satisfies the ratio of the refractive index of the first layer to the refractive index of the second layer. For example, it is preferably 1.47 or more and 1.80 or less, more preferably 1.50 or more and 1.75 or less, and even more preferably 1.53 or more and 1.70 or less. Usually, the refractive index of the first layer is higher than the refractive index of the second layer, and the refractive index of the first layer is within the above range. It can be made close to 1, and the absolute value of the difference between the yellowness degrees YI1 and YI2 can be reduced. When the refractive index of the first layer is within the above range, the difference from the refractive index of the base layer can be reduced, and the reflection of light at the interface between the first layer and the base layer can be suppressed. can.

The thickness of the first layer can also be the same as in the first embodiment.

(ii) Material of First Layer The material of the first layer can be the same as that of the first embodiment.

(iii) Method for forming the first layer The method for forming the first layer can also be the same as in the first embodiment.

(c) Third layer In this embodiment, a third layer having a higher refractive index than the first layer and the second layer is disposed between the first layer and the second layer. may By stacking the first layer, the third layer, and the second layer, which have different refractive indices, in this order, it is possible to suppress the reflection of light by utilizing the light interference effect of the thin film, and to suppress the reflection of light by transmitted light. It is possible to suppress the generation of interference fringes.

In this embodiment, the magnitude relation of the refractive indices of the first layer, the second layer, and the third layer is such that the refractive index of the second layer<refractive index of the first layer<refractive index of the third layer. The refractive index of the third layer may be higher than the refractive index of the first layer and the second refractive index, for example, preferably 1.55 or more and 2.50 or less, and 1.60 or more and 2.20 or less. is more preferably 1.65 or more and 2.00 or less. If the refractive index of the third layer is within the above range, the reflectance can be easily adjusted by adjusting the refractive indices and thicknesses of the first, second and third layers.

The thickness of the third layer is appropriately adjusted according to the refractive index of the third layer. The thickness of the third layer is, for example, preferably 20 nm or more and 500 nm or less, more preferably 30 nm or more and 300 nm or less, and even more preferably 40 nm or more and 200 nm or less. If the thickness of the third layer is within the above range, the reflectance can be easily adjusted by adjusting the refractive index and thickness of the first, second and third layers. Also, if the thickness of the third layer is too thin, the film strength may decrease.

The material of the third layer is not particularly limited as long as it is possible to obtain the third layer satisfying the above refractive index and thickness. The third layer, for example, contains a resin and high refractive index particles having a higher refractive index than the resin, or contains a high refractive index resin having the above refractive index, or has the above refractive index High refractive index inorganic materials can be included.

When the third layer contains a resin and high refractive index particles, the high refractive index particles have a higher refractive index than the resin, and it is possible to obtain a third layer that satisfies the above refractive index. It is not particularly limited as long as it is a material. The high refractive index particles may be either inorganic particles or organic particles.
Examples of inorganic particles include zirconium oxide, silicon monoxide, hafnium oxide, tantalum oxide, niobium oxide, cerium oxide, titanium oxide, zinc oxide, aluminum oxide, magnesium oxide, yttrium oxide, lanthanum fluoride, and cerium fluoride. mentioned.

When the third layer contains resin and high refractive index particles, the resin may be the same as in the first embodiment.

Further, when the third layer contains a high refractive index resin, the high refractive index resin may be any resin that allows the third layer composed of the high refractive index resin to satisfy the above refractive index. Examples thereof include curable resins cured by heat or irradiation with ionizing radiation such as ultraviolet rays or electron beams. Examples of curable resins include thermosetting resins and ionizing radiation curable resins. Further, examples of the ionizing radiation curable resin include ultraviolet curable resin and electron beam curable resin.

Further, when the third layer contains a high refractive index inorganic material, the high refractive index inorganic material is an inorganic material capable of satisfying the above refractive index for the third layer composed of the high refractive index inorganic material. Examples include zirconium oxide, silicon monoxide, hafnium oxide, tantalum oxide, niobium oxide, cerium oxide, titanium oxide, zinc oxide, aluminum oxide, magnesium oxide, yttrium oxide, lanthanum fluoride, and cerium fluoride. be done.

The third layer may contain a photopolymerization initiator when an ultraviolet curable resin is used as the resin. In addition, the third layer may contain various additives according to desired physical properties. Additives may be the same as those used in the second layer.

A method for forming the third layer is appropriately selected according to the material of the third layer. When the third layer contains a resin and high refractive index particles, and when the third layer contains a high refractive index resin, as a method for forming the third layer, for example, the third layer is formed on the first layer. A method of applying and curing a three-layer resin composition may be used. Further, when the third layer contains a high refractive index inorganic material, examples of the method for forming the third layer include a vacuum deposition method and a sputtering method.

3. Base Material Layer The base material layer in the present disclosure is a member that supports the first layer and the second layer and has transparency.

The substrate layer is not particularly limited as long as it has transparency, and examples thereof include resin substrates and glass substrates.

(1) Resin substrate The resin constituting the resin substrate is not particularly limited as long as it can obtain a transparent resin substrate. Examples include polyimide resins, polyamide resins, Examples include polyester-based resins. Examples of polyimide-based resins include polyimide, polyamideimide, polyetherimide, and polyesterimide. Examples of polyester resins include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. Among them, polyimide-based resins, polyamide-based resins, or mixtures thereof are preferable, and polyimide-based resins are more preferable, because they have bending resistance and excellent hardness and transparency.

The polyimide-based resin is not particularly limited as long as it can obtain a resin substrate having transparency, but among the above, polyimide and polyamideimide are preferably used. Flexibility and bending resistance can be enhanced, and since the refractive index is relatively high, the reflectance can be easily adjusted.

(a) Polyimide Polyimide is obtained by reacting a tetracarboxylic acid component and a diamine component. The polyimide is not particularly limited as long as it has transparency and rigidity. ) preferably has at least one structure selected from the group consisting of structures represented by

In the above general formula (1), R ¹ is a tetravalent group that is a tetracarboxylic acid residue, R ² is a trans-cyclohexanediamine residue, a trans-1,4-bismethylenecyclohexanediamine residue, 4,4 '-diaminodiphenylsulfone residue, 3,4'-diaminodiphenylsulfone residue, and at least one divalent group selected from the group consisting of a divalent group represented by the following general formula (2) . n represents the number of repeating units and is 1 or more.

In general formula (2) above, R ³ and R ⁴ each independently represent a hydrogen atom, an alkyl group, or a perfluoroalkyl group.

In the above general formula (3), R ⁵ is a cyclohexanetetracarboxylic acid residue, a cyclopentanetetracarboxylic acid residue, a dicyclohexane-3,4,3′,4′-tetracarboxylic acid residue, and 4,4′ At least one tetravalent group selected from the group consisting of -(hexafluoroisopropylidene) ^diphthalic acid residues, and R6 represents a divalent group that is a diamine residue.
n' represents the number of repeating units and is 1 or more.

The term "tetracarboxylic acid residue" refers to a residue obtained by removing four carboxyl groups from a tetracarboxylic acid, and has the same structure as a residue obtained by removing the acid dianhydride structure from a tetracarboxylic dianhydride. show. Moreover, the term "diamine residue" refers to a residue obtained by removing two amino groups from a diamine.

In the above general formula (1), R ¹ is a tetracarboxylic acid residue, which can be a residue obtained by removing the acid dianhydride structure from a tetracarboxylic dianhydride. Examples of tetracarboxylic dianhydrides include those described in International Publication No. 2018/070523. As R ¹ in the above general formula (1), 4,4′-(hexafluoroisopropylidene)diphthalic acid residue, 3,3′,4 ,4′-biphenyltetracarboxylic acid residue, pyromellitic acid residue, 2,3′,3,4′-biphenyltetracarboxylic acid residue, 3,3′,4,4′-benzophenonetetracarboxylic acid residue , 3,3′,4,4′-diphenylsulfonetetracarboxylic acid residue, 4,4′-oxydiphthalic acid residue, cyclohexanetetracarboxylic acid residue, and cyclopentanetetracarboxylic acid residue. Further, 4,4'-(hexafluoroisopropylidene) diphthalic acid residue, 4,4'-oxydiphthalic acid residue, and 3,3',4,4'-diphenyl It preferably contains at least one selected from the group consisting of sulfonetetracarboxylic acid residues.

R ¹ preferably contains 50 mol % or more of these suitable residues in total, more preferably 70 mol % or more, and even more preferably 90 mol % or more.

Further, R ¹ is selected from the group consisting of 3,3′,4,4′-biphenyltetracarboxylic acid residue, 3,3′,4,4′-benzophenonetetracarboxylic acid residue, and pyromellitic acid residue. A tetracarboxylic acid residue group (group A) suitable for improving rigidity such as at least one selected and a 4,4′-(hexafluoroisopropylidene)diphthalic acid residue, 2,3′ , 3,4′-biphenyltetracarboxylic acid residue, 3,3′,4,4′-diphenylsulfonetetracarboxylic acid residue, 4,4′-oxydiphthalic acid residue, cyclohexanetetracarboxylic acid residue, and cyclo It is also preferable to use a mixture of a tetracarboxylic acid residue group (group B) suitable for improving transparency, such as at least one selected from the group consisting of pentanetetracarboxylic acid residues.

In this case, the content ratio of the tetracarboxylic acid residue group (group A) suitable for improving rigidity and the tetracarboxylic acid residue group (group B) suitable for improving transparency is , 0.05 mol of tetracarboxylic acid residue group (group A) suitable for improving rigidity per 1 mol of tetracarboxylic acid residue group (group B) suitable for improving transparency It is preferably 9 mol or less, more preferably 0.1 mol or more and 5 mol or less, and still more preferably 0.3 mol or more and 4 mol or less.

R ² in the above general formula (1) includes, among others, a 4,4′-diaminodiphenylsulfone residue, a 3,4′-diaminodiphenylsulfone residue, a 3,4′-diaminodiphenylsulfone residue, and a and at least one divalent group selected from the group consisting of the divalent groups represented by the general formula (2), and further a 4,4′-diaminodiphenylsulfone residue, 3, 4′-Diaminodiphenylsulfone residue, and at least one divalent group selected from the group consisting of the divalent group represented by the general formula (2), wherein R ³ and R ⁴ are perfluoroalkyl groups. It is preferably a group.

As R ⁵ in the above general formula (3), 4,4′-(hexafluoroisopropylidene)diphthalic acid residue, 3,3′,4 , 4′-diphenylsulfonetetracarboxylic acid residues, and oxydiphthalic acid residues.

R ⁵ preferably contains 50 mol % or more of these suitable residues, more preferably 70 mol % or more, and even more preferably 90 mol % or more.

R6 in the above general formula ( ³ ) is a diamine residue, and can be a residue obtained by removing two amino groups from a diamine. Examples of diamines include those described in International Publication No. 2018/070523. As R ⁶ in the general formula (3), 2,2′-bis(trifluoromethyl)benzidine residue, bis[4-(4- aminophenoxy)phenyl]sulfone residue, 4,4′-diaminodiphenylsulfone residue, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane residue, bis[4-(3-amino phenoxy)phenyl]sulfone residue, 4,4′-diamino-2,2′-bis(trifluoromethyl)diphenyl ether residue, 1,4-bis[4-amino-2-(trifluoromethyl)phenoxy]benzene residue, 2,2-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]hexafluoropropane residue, 4,4′-diamino-2-(trifluoromethyl)diphenyl ether residue, 4 ,4'-diaminobenzanilide residue, N,N'-bis(4-aminophenyl)terephthalamide residue, and at least one selected from the group consisting of 9,9-bis(4-aminophenyl)fluorene residue It preferably contains a divalent group of 2,2'-bis(trifluoromethyl)benzidine residue, bis[4-(4-aminophenoxy)phenyl]sulfone residue, and 4,4' -It preferably contains at least one divalent group selected from the group consisting of diaminodiphenylsulfone residues.

R ⁶ preferably contains 50 mol % or more of these suitable residues in total, more preferably 70 mol % or more, and even more preferably 90 mol % or more.

Further, as R ⁶ , bis[4-(4-aminophenoxy)phenyl]sulfone residue, 4,4′-diaminobenzanilide residue, N,N′-bis(4-aminophenyl)terephthalamide residue, A diamine residue group (group C) and 2,2′-bis(trifluoromethyl)benzidine residue, 4,4′-diaminodiphenylsulfone residue, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane residue group, bis[4-(3-aminophenoxy)phenyl]sulfone residue, 4,4′-diamino-2,2′-bis(trifluoromethyl)diphenyl ether residue, 1,4-bis[4-amino- 2-(trifluoromethyl)phenoxy]benzene residue, 2,2-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]hexafluoropropane residue, 4,4′-diamino-2- A group of diamine residues suitable for improving transparency, such as at least one selected from the group consisting of (trifluoromethyl)diphenyl ether residues and 9,9-bis(4-aminophenyl)fluorene residues. (Group D) is also preferably used in combination.

In this case, the content ratio of the diamine residue group (group C) suitable for improving rigidity and the diamine residue group (group D) suitable for improving transparency is The diamine residue group (group C) suitable for improving rigidity is 0.05 mol or more and 9 mol or less per 1 mol of the diamine residue group (group D) suitable for improving rigidity. It is preferably 0.1 mol or more and 5 mol or less, and more preferably 0.3 mol or more and 4 mol or less.

In the structures represented by the general formulas (1) and (3), n and n' each independently represent the number of repeating units and are 1 or more. The number n of repeating units in the polyimide may be appropriately selected depending on the structure, and is not particularly limited. The average number of repeating units can be, for example, 10 or more and 2000 or less, preferably 15 or more and 1000 or less.

Also, the polyimide may partially contain a polyamide structure. Polyamide structures that may be included include, for example, polyamideimide structures containing tricarboxylic acid residues such as trimellitic anhydride, and polyamide structures containing dicarboxylic acid residues such as terephthalic acid.

From the viewpoint of improving transparency and improving surface hardness, a tetravalent group that is a tetracarboxylic acid residue of R ¹ or R ⁵ and a divalent group that is a diamine residue of R ² or R ⁶ At least one of the groups is an alkylene group containing an aromatic ring, and (i) a fluorine atom, (ii) an aliphatic ring, and (iii) a sulfonyl group or a fluorine-substituted aromatic ring. It is preferable to include at least one selected from the group consisting of a structure linked with Polyimide contains at least one selected from a tetracarboxylic acid residue having an aromatic ring and a diamine residue having an aromatic ring, so that the molecular skeleton becomes rigid, the orientation increases, and the surface hardness improves. Such an aromatic ring skeleton tends to extend the absorption wavelength to longer wavelengths, and tends to lower the transmittance in the visible light region. On the other hand, if the polyimide contains (i) a fluorine atom, the electron state in the polyimide skeleton can be made difficult to transfer, resulting in improved transparency.
In addition, when the polyimide contains (ii) an alicyclic ring, the transparence of charges in the polyimide skeleton can be inhibited by severing the conjugation of π electrons in the polyimide skeleton, thereby improving the transparency. Further, when the polyimide (iii) contains a structure in which the aromatic rings are linked by a sulfonyl group or an alkylene group optionally substituted with fluorine, the charge in the skeleton is removed by breaking the conjugation of the π electrons in the polyimide skeleton. Transparency improves from the point that movement can be inhibited.

Among them, from the viewpoint of improving transparency and improving surface hardness, R ¹ or R ⁵ is a tetravalent group that is a tetracarboxylic acid residue, and R ² or R ⁶ is a diamine residue 2 At least one of the valent groups preferably contains an aromatic ring and a fluorine atom, and the divalent group which is a diamine residue of R ² or R ⁶ may contain an aromatic ring and a fluorine atom. preferable.

Specific examples of such polyimide include those having a specific structure described in WO2018/070523.

Polyimide can be synthesized by a known method. A commercially available polyimide may also be used. Commercially available polyimides include, for example, Neoprim (registered trademark) manufactured by Mitsubishi Gas Chemical Company, Inc., and the like.

The weight average molecular weight of the polyimide is, for example, preferably 3,000 or more and 500,000 or less, more preferably 5,000 or more and 300,000 or less, and even more preferably 10,000 or more and 200,000 or less. If the weight-average molecular weight is too small, sufficient strength may not be obtained. If the weight-average molecular weight is too large, the viscosity increases and the solubility decreases. may not be obtained.

The weight average molecular weight of polyimide can be measured by gel permeation chromatography (GPC). Specifically, the polyimide is used as an N-methylpyrrolidone (NMP) solution with a concentration of 0.1% by mass, and the developing solvent is a 30 mmol% LiBr-NMP solution with a water content of 500 ppm or less. 8120, column used: GPC LF-804 (manufactured by SHODEX), measurement is performed under the conditions of a sample injection amount of 50 μL, a solvent flow rate of 0.4 mL/min, and 37°C. The weight average molecular weight is determined based on a polystyrene standard sample having the same concentration as the sample.

(b) Polyamideimide The polyamideimide is not particularly limited as long as it can obtain a transparent resin base material, and includes, for example, structural units derived from dianhydrides and structural units derived from diamines. Examples include those having a first block and a second block containing a structural unit derived from an aromatic dicarbonyl compound and a structural unit derived from an aromatic diamine. In the polyamideimide, the dianhydride can include, for example, biphenyltetracarboxylic dianhydride (BPDA) and 2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA). Also, the diamine can include bistrifluoromethylbenzidine (TFDB). That is, the polyamideimide has a first block copolymerized with a monomer containing a dianhydride and a diamine, and a second block copolymerized with a monomer containing an aromatic dicarbonyl compound and an aromatic diamine. It has a structure obtained by imidizing the polyamideimide precursor.
By having the first block containing an imide bond and the second block containing an amide bond, the above polyamideimide is excellent not only in optical properties but also in thermal and mechanical properties.
In particular, by using bistrifluoromethylbenzidine (TFDB) as the diamine forming the first block, thermal stability and optical properties can be improved. Further, by using 2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) and biphenyltetracarboxylic dianhydride (BPDA) as dianhydrides forming the first block, It is possible to improve birefringence and ensure heat resistance.

The dianhydrides forming the first block include two types of dianhydrides, namely 6FDA and BPDA. The first block may include a polymer to which TFDB and 6FDA are bonded and a polymer to which TFDB and BPDA are bonded, which are separated based on separate repeating units, and may be included in the same repeating unit. may be regularly arranged, or may be contained in a completely random arrangement.

Among the monomers forming the first block, BPDA and 6FDA are preferably contained in a molar ratio of 1:3 to 3:1 as dianhydrides. This is because not only optical properties can be ensured, but also deterioration of mechanical properties and heat resistance can be suppressed, and excellent birefringence can be obtained.

Preferably, the molar ratio of the first block and the second block is between 5:1 and 1:1.
If the content of the second block is extremely low, the effect of improving the thermal stability and mechanical properties of the second block may not be sufficiently obtained. Further, when the content of the second block is higher than the content of the first block, although the thermal stability and mechanical properties can be improved, the yellowness, transmittance, etc. are lowered, and the optical properties are deteriorated. , the birefringence properties may also be enhanced. The first block and the second block may be random copolymers or block copolymers. The repeating unit of the block is not particularly limited.

Examples of the aromatic dicarbonyl compound forming the second block include terephthaloyl chloride (p-Terephthaloyl chloride, TPC), terephthalic acid, isophthaloyl dichloride (Iso-phthaloyl dichloride) and 4,4 One or more selected from the group consisting of '-benzoyl chloride (4,4'-benzoyl chloride) can be mentioned. Preferably, one or more selected from terephthaloyl chloride (p-Terephthaloyl chloride, TPC) and isophthaloyl dichloride (Iso-phthaloyl dichloride) can be used.

Diamines forming the second block include, for example, 2,2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane (HFBAPP), bis(4-(4-aminophenoxy)phenyl)sulfone (BAPS) ), bis(4-(3-aminophenoxy)phenyl)sulfone (BAPSM), 4,4′-diaminodiphenylsulfone (4DDS), 3,3′-diaminodiphenylsulfone (3DDS), 2,2-bis(4 -(4-aminophenoxy)phenylpropane (BAPP), 4,4'-diaminodiphenylpropane (6HDA), 1,3-bis(4-aminophenoxy)benzene (134APB), 1,3-bis(3-amino phenoxy)benzene (133APB), 1,4-bis(4-aminophenoxy)biphenyl (BAPB), 4,4′-bis(4-amino-2-trifluoromethylphenoxy)biphenyl (6FAPBP), 3,3- Diamino-4,4-dihydroxydiphenylsulfone (DABS), 2,2-bis(3-amino-4-hydroxyloxyphenyl)propane (BAP), 4,4'-diaminodiphenylmethane (DDM), 4,4'- Mention may be made of diamines having one or more flexible groups selected from the group consisting of oxydianiline (4-ODA) and 3,3'-oxydianiline (3-ODA).

When using an aromatic dicarbonyl compound, it is easy to achieve high thermal stability and mechanical properties, but it may exhibit high birefringence due to the benzene ring in the molecular structure. Therefore, in order to suppress the decrease in birefringence due to the second block, it is preferable to use a diamine having a flexible group introduced into its molecular structure. Specifically, diamines include bis(4-(3-aminophenoxy)phenyl)sulfone (BAPSM), 4,4′-diaminodiphenylsulfone (4DDS) and 2,2-bis(4-(4-aminophenoxy ) phenyl) hexafluoropropane (HFBAPP). In particular, a diamine such as BAPSM having a long flexible group and having a substituent at the meta position can exhibit a superior birefringence.

dianhydrides, including biphenyltetracarboxylic dianhydride (BPDA) and 2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA); and diamines, including bistrifluoromethylbenzidine (TFDB). A polyamideimide precursor containing a copolymerized first block and a second block obtained by copolymerizing an aromatic dicarbonyl compound and an aromatic diamine in its molecular structure has a weight-average molecular weight measured by GPC of, for example, 200. ,000 or more and 215,000 or less, and the viscosity is preferably, for example, 2400 poise or more and 2600 poise or less.

Polyamideimide can be obtained by imidating a polyamideimide precursor. Moreover, a polyamide-imide film can be obtained using a polyamide-imide.
For the method for imidizing the polyamideimide precursor and the method for producing the polyamideimide film, for example, Japanese Patent Publication No. 2018-506611 can be referred to.

(2) Glass Substrate The glass constituting the glass substrate is not particularly limited as long as it has transparency, and examples thereof include silicate glass and silica glass. Among them, borosilicate glass, aluminosilicate glass, and aluminoborosilicate glass are preferable, and alkali-free glass is more preferable. Commercially available glass substrates include, for example, ultra-thin sheet glass G-Leaf manufactured by Nippon Electric Glass Co., Ltd., ultra-thin glass manufactured by Matsunami Glass Industry Co., Ltd., and the like.

Moreover, it is also preferable that the glass constituting the glass substrate is chemically strengthened glass. Chemically strengthened glass is excellent in mechanical strength and is preferable in that it can be made thinner accordingly. Chemically strengthened glass is glass whose mechanical properties are strengthened by a chemical method, typically by partially exchanging ion species, such as replacing sodium with potassium, in the vicinity of the surface of the glass. It has a compressive stress layer.

Examples of glass constituting the chemically strengthened glass substrate include aluminosilicate glass, soda lime glass, borosilicate glass, lead glass, alkali barium glass, and aluminoborosilicate glass.

Commercially available chemically strengthened glass substrates include, for example, Corning's Gorilla Glass, AGC's Dragontrail, and Schott's chemically strengthened glass.

(3) Structure of Base Layer The base layer may also serve as the first layer. When the substrate layer also serves as the first layer, for example, the refractive index is relatively high, and it is necessary to improve flexibility and bending resistance, so polyimide resin, polyamide resin, polyester resin etc. are preferably used.

The thickness of the base material layer is not particularly limited as long as it has a thickness that allows flexibility, and is appropriately selected according to the type of the base material layer.

The thickness of the resin base material is, for example, preferably 10 μm or more and 100 μm or less, and more preferably 25 μm or more and 80 μm or less. When the thickness of the resin base material is within the above range, good flexibility and sufficient hardness can be obtained. In addition, curling of the laminate for a display device can also be suppressed. Furthermore, it is preferable in terms of reducing the weight of the laminate for a display device.

The thickness of the glass substrate is, for example, preferably 200 μm or less, more preferably 15 μm or more and 100 μm or less, further preferably 20 μm or more and 90 μm or less, and 25 μm or more and 80 μm or less. is particularly preferred. When the thickness of the glass substrate is within the above range, good flexibility and sufficient hardness can be obtained. In addition, curling of the laminate for a display device can also be suppressed. Furthermore, it is preferable in terms of reducing the weight of the laminate for a display device.

4. Other Layers The laminate for a display device in the present disclosure can have other layers in addition to the base layer, first layer, and second layer described above.

(1) Hard Coat Layer The laminate for a display device according to the present disclosure can have a hard coat layer 5 between the base material layer 2 and the first layer 3, as shown in FIG. 5, for example. The hard coat layer is a member for increasing surface hardness. By arranging the hard coat layer, load resistance can be improved. In particular, when the base material layer is a resin base material, the load resistance can be effectively improved by disposing the hard coat layer.

The refractive index of the hard coat layer is not particularly limited as long as it satisfies the above refractive index of the first layer. It is more preferably 0.75 or less, and further preferably 1.53 or more and 1.70 or less. When the refractive index of the hard coat layer is within the above range, the difference between the refractive index of the base layer and the refractive index of the first layer can be reduced, and the interface between the hard coat layer and the first layer can be reduced. The reflection of light at the surface and the reflection of light at the interface between the hard coat layer and the base material layer can be suppressed.

As a material for the hard coat layer, for example, an organic material, an inorganic material, an organic-inorganic composite material, or the like can be used.

Among them, the material of the hard coat layer is preferably an organic material. As the organic material, for example, it is preferable to use a cured resin cured by irradiation with heat or ionizing radiation such as ultraviolet rays or electron beams. The cured resin may be the same as the cured resin used for the first layer and the second layer.

The hard coat layer may contain a polymerization initiator as needed. As the polymerization initiator, radical polymerization initiators, cationic polymerization initiators, radical and cationic polymerization initiators, and the like can be appropriately selected and used. These polymerization initiators are decomposed by at least one of light irradiation and heating to generate radicals or cations to promote radical polymerization and cationic polymerization. In some cases, the polymerization initiator is completely decomposed and does not remain in the functional layer.

The hard coat layer may contain a photopolymerization initiator when an ultraviolet curable resin is used as the resin. Further, the hard coat layer may contain various additives according to desired physical properties. Additives may be the same as those used in the first and second layers.

The thickness of the hard coat layer may be appropriately selected depending on the function of the hard coat layer and the application of the laminate for display device. The thickness of the hard coat layer is, for example, preferably 0.5 μm or more and 50 μm or less, more preferably 1.0 μm or more and 40 μm or less, further preferably 1.5 μm or more and 30 μm or less. It is particularly preferable to be 0 μm or more and 20 μm or less. If the thickness of the hard coat layer is within the above range, it is possible to obtain sufficient hardness as the hard coat layer.

As a method for forming the hard coat layer, for example, a method of applying a hard coat layer resin composition onto the substrate layer and curing the resin composition can be used.

(2) Impact-absorbing layer The laminate for a display device in the present disclosure is, for example, between the base layer 2 and the first layer 3 as shown in FIG. 6, or the base layer 2 as shown in FIG. can have a shock absorbing layer 6 on the side opposite the first layer 3 of the . By arranging the shock absorbing layer, when a shock is applied to the laminate for a display device, the shock can be absorbed and the shock resistance can be improved. Moreover, when the base material layer is a glass base material, cracking of the glass base material can be suppressed.

The material for the impact absorbing layer is not particularly limited as long as it has impact absorbing properties and can provide a transparent impact absorbing layer. Examples include polyethylene terephthalate (PET) and polyethylene naphthalate. (PEN), urethane resin, epoxy resin, polyimide, polyamideimide, acrylic resin, triacetyl cellulose (TAC), silicone resin, and the like. These materials may be used singly or in combination of two or more.

The impact-absorbing layer can further contain additives as needed. Examples of additives include inorganic particles, organic particles, ultraviolet absorbers, antioxidants, light stabilizers, surfactants, and adhesion improvers.

The thickness of the impact absorption layer may be any thickness that can absorb impact, and for example, it is preferably 5 μm or more and 150 μm or less, more preferably 10 μm or more and 120 μm or less, further preferably 15 μm or more and 100 μm. You can:

As the impact absorbing layer, for example, a resin film may be used. Further, for example, a shock absorbing layer may be formed by applying a composition for a shock absorbing layer onto the base material layer.

(3) Adhesive layer for sticking The laminate for a display device in the present disclosure may have an adhesive layer 7 for sticking on the surface of the base material layer 2 opposite to the first layer 3, as shown in FIG. can. The laminate for a display device can be attached to, for example, a display panel or the like via the adhesive layer for attachment.

The adhesive used for the sticking adhesive layer is not particularly limited as long as it has transparency and is capable of adhering the laminate for a display device to a display panel or the like. Curable adhesives, ultraviolet curable adhesives, two-liquid curable adhesives, hot-melt adhesives, pressure-sensitive adhesives (so-called adhesives), and the like can be mentioned.

Among them, for example, as shown in FIG. 7, when an adhesive layer 7 for attachment, a shock absorbing layer 6, and an interlayer adhesive layer 9 described later are arranged in order, the adhesive layer for attachment and the interlayer adhesive layer are sensitive. It preferably contains a pressure adhesive, ie it is preferably a pressure sensitive adhesive layer. In general, the pressure-sensitive adhesive layer is a relatively soft layer among the above adhesive-containing adhesive layers. The impact resistance can be improved by arranging the impact absorbing layer between the relatively soft pressure-sensitive adhesive layers. This is because the pressure-sensitive adhesive layer is relatively soft and easily deformable, so that when the laminate for a display device is subjected to an impact, the pressure-sensitive adhesive layer does not suppress the deformation of the impact-absorbing layer, and the impact-absorbing layer is deformed. Since it becomes easy to deform, it is thought that a greater impact absorption effect is exhibited.

The thickness of the adhesive layer for attachment is, for example, preferably 10 μm or more and 100 μm or less, more preferably 25 μm or more and 80 μm or less, and even more preferably 40 μm or more and 60 μm or less. If the thickness of the sticking adhesive layer is too thin, there is a possibility that the display device laminate and the display panel or the like cannot be sufficiently adhered. Moreover, when the thickness of the adhesive layer for sticking is too thick, flexibility may be impaired.

As the sticking adhesive layer, for example, an adhesive film may be used. Also, for example, an adhesive composition may be applied onto a support or a substrate layer to form an adhesive layer for attachment.

(4) Antifouling layer In the laminate for a display device according to the present disclosure, for example, as shown in FIG. may By disposing the antifouling layer, antifouling properties can be imparted to the laminate for a display device. In the present disclosure, the thickness of the antifouling layer is relatively thin as described later, so it is presumed that it does not affect thin film interference.

As the material for the antifouling layer, a general antifouling layer material such as a fluorine compound or a silicone compound can be applied.
In the present embodiment, in a mode of use in which the images of the first display area and the second display area are observed in a folded state, the antifouling can be repeatedly wiped off fingerprints, stains, etc. attached to the first display area or the second display area. A fluorine compound is preferable from the viewpoint of imparting properties and transparency and maintaining the visibility of the image.

Examples of the fluorine compound include fluorine compounds having reactive functional groups such as (meth)acryloyl groups, vinyl groups, epoxy groups, oxetanyl groups, and ethylenically unsaturated bond groups, fluorine compounds having the above reactive functional groups and silicon, and the like. For example, a fluorine compound having a fluoroalkylene group in the main chain, a fluorine compound having a fluoroalkylene group in the main chain and side chains, a fluorine compound having a fluoroalkyl group, a fluorine compound having a siloxane bond, a reactive functional group Fluorine compounds having a silicone containing, fluorine compounds having a reactive functional group and a perfluoropolyether group, fluorine compounds having a silane unit containing a perfluoropolyether group, etc. can be mentioned,
In this embodiment, it is preferable to use a fluorine compound having a silane unit containing a perfluoropolyether group.

The thickness of the antifouling layer is, for example, preferably 1 nm or more and 30 nm or less, more preferably 2 nm or more and 20 nm or less, and even more preferably 3 nm or more and 10 nm or less. If the thickness of the antifouling layer is within the above range, antifouling properties and durability can be improved.

The method for forming the antifouling layer is appropriately selected according to the material of the antifouling layer. is mentioned.

(5) Interlayer adhesive layer In the laminate for a display device according to the present disclosure, an interlayer adhesive layer may be arranged between each layer.

As the adhesive used for the interlayer adhesive layer, the same adhesive as used for the adhesive layer for attachment can be used.

The thickness, formation method, etc. of the interlayer adhesive layer can be the same as the thickness, formation method, etc. of the adhesive layer for attachment.

5. Use of Laminate for Display Device The laminate for a display device according to the present disclosure can be used as a front plate arranged closer to the viewer than the display panel in a display device. Among others, the laminate for a display device according to the present disclosure can be suitably used for a front plate in a flexible display device such as a foldable display, a rollable display, and a bendable display. In particular, the laminate for a display device according to the present disclosure can improve visibility in a usage pattern in which an image is observed while the display device is folded, and thus can be suitably used as a front plate of a foldable display. .

Further, the display device laminate in the present disclosure can be used, for example, as a front plate in a display device such as a smartphone, a tablet terminal, a wearable terminal, a personal computer, a television, a digital signage, a public information display (PID), or an in-vehicle display. can be done.

B. Display Device A display device according to the present disclosure includes a display panel and the above-described display device laminate disposed on the viewer side of the display panel.

FIG. 9 is a schematic cross-sectional view showing an example of a display device according to the present disclosure. As shown in FIG. 9 , the display device 30 includes a display panel 31 and the display device laminate 1 arranged on the viewer side of the display panel 31 . In the display device 30 , the display device laminate 1 and the display panel 31 can be bonded together, for example, via the bonding adhesive layer 7 of the display device laminate 1 .

When the laminate for a display device according to the present disclosure is arranged on the surface of the display device, the second layer is arranged on the outside and the substrate layer is arranged on the inside.

The method for disposing the laminate for a display device according to the present disclosure on the surface of the display device is not particularly limited, but includes, for example, a method via an adhesive layer.

Examples of the display panel in the present disclosure include display panels used in display devices such as organic EL display devices and liquid crystal display devices.

The display device according to the present disclosure can have a touch panel member between the display panel and the laminate for display device.

The display device according to the present disclosure is preferably a flexible display device such as a foldable display, a rollable display, or a bendable display.

Also, the display device according to the present disclosure is preferably foldable. That is, the display device in the present disclosure is preferably a foldable display. The display device according to the present disclosure has excellent visibility in a usage pattern in which an image is observed in a folded state, and is suitable as a foldable display.

Note that the present disclosure is not limited to the above embodiments. The above embodiment is an example, and any device that has substantially the same configuration as the technical idea described in the claims of the present disclosure and achieves the same effect is the present invention. It is included in the technical scope of the disclosure.

Examples and comparative examples are given below to further illustrate the present disclosure.

[Example 1]
(1) Formation of First Layer First, each component was blended so as to have the composition shown below to obtain a resin composition 1 for functional layer.

<Composition of Resin Composition 1 for Functional Layer>
・Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name “Omnirad184”, manufactured by IGM Resins B.V.): 3 parts by mass ・Urethane acrylate (product name “8UX-047A”, manufactured by Taisei Fine Chemical Co., Ltd.): 85 Parts by mass ・Pentaerythritol tetraacrylate (product name “ATM-4E”, manufactured by Shin-Nakamura Chemical Co., Ltd.): 15 parts by mass ・Methyl isobutyl ketone: 200 parts by mass

Next, a 50 μm-thick polyimide film (Mitsubishi Gas Chemical Co., Ltd. “Neoprim”) is used as the base layer, and the functional layer resin composition 1 is applied on the base layer with a bar coater to form a coating film. formed. Then, this coating film is heated at 70 ° C. for 1 minute to evaporate the solvent in the coating film, and an ultraviolet irradiation device (Fusion UV Systems Japan Co., Ltd., light source H bulb) is used to irradiate ultraviolet rays with oxygen concentration. was 200 ppm or less, the coating film was cured by irradiating so that the integrated light amount was 40 mJ/cm ² , and a first layer having a thickness of 3 μm was formed.

(2) Formation of Second Layer First, each component was blended so as to have the composition shown below to obtain a resin composition 2 for functional layer.

<Composition of Resin Composition 2 for Functional Layer>
・Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name “Omnirad184”, manufactured by IGM Resins B.V.): 3 parts by mass ・Urethane acrylate (product name “EBECRYL8209”, manufactured by Daicel Ornex): 72 mass Part ・ Polyfunctional acrylate (product name “M-510”, manufactured by Toagosei Co., Ltd.): 28 parts by mass ・ Low refractive index particles (hollow silica, average primary particle diameter 50 nm, manufactured by JGC Catalysts and Chemicals Co., Ltd.): 70 parts by mass (solid minute 100% conversion value)
・Methyl isobutyl ketone: 220 parts by mass

Next, the functional layer resin composition 2 was applied on the first layer with a bar coater to form a coating film. Then, this coating film is heated at 70 ° C. for 1 minute to evaporate the solvent in the coating film, and an ultraviolet irradiation device (Fusion UV Systems Japan Co., Ltd., light source H bulb) is used to irradiate ultraviolet rays with oxygen concentration. was 200 ppm or less, the coating film was cured by irradiating so that the integrated light amount was 400 mJ/cm ² , and a second layer having a thickness of 3 μm was formed.

(3) Formation of antifouling layer The surface of the second layer was reformed by plasma treatment at an output of 200 W for 1 minute.
After that, on the surface-modified second layer, a film of a fluorine compound (manufactured by Daikin Industries, Ltd., product name "OPTOOL UD120") is formed by a vacuum deposition method using a vacuum deposition device (manufactured by ULVAC, Inc.) to a thickness of 7 nm. formed an antifouling layer.

[Example 2]
A laminate was produced in the same manner as in Example 1, except that the thickness of the second layer was 10 μm.

[Example 3]
A laminate was produced in the same manner as in Example 1, except that the second layer was formed using the functional layer resin composition 3 described below.

<Composition of Resin Composition 3 for Functional Layer>
・Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name “Omnirad184”, manufactured by IGM Resins B.V.): 3 parts by mass ・Urethane acrylate (product name “EBECRYL8209”, manufactured by Daicel Ornex): 63 mass Part ・ Polyfunctional acrylate (product name “M-510”, manufactured by Toagosei Co., Ltd.): 37 parts by mass ・ Low refractive index particles (hollow silica, average primary particle diameter 50 nm, manufactured by JGC Catalysts and Chemicals Co., Ltd.): 130 parts by mass (solid minute 100% conversion value)
・Methyl isobutyl ketone: 220 parts by mass

[Example 4]
A laminate was produced in the same manner as in Example 1, except that the first layer was formed using the functional layer resin composition 4 described below.

<Composition of the functional layer resin composition 4>
・Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name “Omnirad184”, manufactured by IGM Resins B.V.): 3 parts by mass ・Urethane acrylate (product name “8UX-047A”, manufactured by Taisei Fine Chemical Co., Ltd.): 89 Parts by mass ・Pentaerythritol tetraacrylate (product name “ATM-4E”, manufactured by Shin-Nakamura Chemical Co., Ltd.): 11 parts by mass ・High refractive index particles (zirconia, average primary particle size 20 nm, manufactured by CIK Nanotech): 170 parts by mass ( 100% solid content conversion value)
・Methyl isobutyl ketone: 240 parts by mass

[Example 5]
An example in which the base material layer also serves as the first layer was used. A 50 μm-thick polyimide film (“Neoprim” manufactured by Mitsubishi Gas Chemical Company, Inc.) was used as a base layer that also serves as the first layer.

The surface of the first layer was modified by plasma treatment with an output of 300 W for 2 minutes.
After that, silicon dioxide (silica) was deposited on the surface-modified first layer by vacuum deposition using a vacuum deposition device (manufactured by ULVAC, Inc.) to form a second layer having a thickness of 90 nm.

Next, in the same manner as in Example 1, an antifouling layer was formed on the second layer to prepare a laminate.

[Example 6]
An example in which the base material layer also serves as the first layer was used. A laminate was produced in the same manner as in Example 5, except that a 30 μm-thick polyamide film (“Mikutron” manufactured by Toray Industries, Inc.) was used as the base layer that also serves as the first layer.

[Example 7]
(1) Formation of 1st layer It carried out similarly to Example 1, and formed the 1st layer on the base material layer.

(2) Formation of Second Layer As in Example 5, a second layer was formed on the first layer.

(3) Formation of Antifouling Layer In the same manner as in Example 1, an antifouling layer was formed on the second layer.

[Example 8]
A laminate was produced in the same manner as in Example 7, except that the thickness of the first layer was 1 μm.

[Example 9]
A laminate was produced in the same manner as in Example 7, except that the following resin composition 5 for functional layer was used to form the first layer.

<Composition of the functional layer resin composition 5>
・Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name “Omnirad184”, manufactured by IGM Resins B.V.): 3 parts by mass ・Urethane acrylate (product name “8UX-047A”, manufactured by Taisei Fine Chemical Co., Ltd.): 87 Parts by mass ・Pentaerythritol tetraacrylate (product name “ATM-4E”, manufactured by Shin-Nakamura Chemical Co., Ltd.): 13 parts by mass ・High refractive index particles (zirconia, average primary particle size 20 nm, manufactured by CIK Nanotech): 90 parts by mass ( 100% solid content conversion value)
・Methyl isobutyl ketone: 240 parts by mass

[Example 10]
A laminate was produced in the same manner as in Example 9, except that the thickness of the second layer was 60 nm.

[Example 11]
A laminate was produced in the same manner as in Example 7, except that a first layer having a thickness of 90 nm was formed using the functional layer resin composition 6 described below.

<Composition of the functional layer resin composition 6>
・Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name “Omnirad184”, manufactured by IGM Resins B.V.): 3 parts by mass ・Urethane acrylate (product name “8UX-047A”, manufactured by Taisei Fine Chemical Co., Ltd.): 87 Parts by mass ・Pentaerythritol tetraacrylate (product name “ATM-4E”, manufactured by Shin-Nakamura Chemical Co., Ltd.): 13 parts by mass ・High refractive index particles (zirconia, average primary particle size 20 nm, manufactured by CIK Nanotech): 90 parts by mass ( 100% solid content conversion value)
・Methyl isobutyl ketone: 320 parts by mass

[Example 12]
A laminate was produced in the same manner as in Example 11, except that the thickness of the first layer was 70 nm.

[Example 13]
An example in which the base material layer also serves as the first layer was used. A 50 μm-thick polyamideimide film (“CPI” manufactured by Kolon Co., Ltd.) was used as a base material that also serves as the first layer.

Next, a second layer was formed on the first layer in the same manner as in Example 1, except that a second layer having a thickness of 90 nm was formed using the functional layer resin composition 7 described below. .

<Composition of Resin Composition 7 for Functional Layer>
・Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name “Omnirad184”, manufactured by IGM Resins B.V.): 3 parts by mass ・Urethane acrylate (product name “EBECRYL8209”, manufactured by Daicel Ornex): 63 mass Part ・ Polyfunctional acrylate (product name “M-510”, manufactured by Toagosei Co., Ltd.): 37 parts by mass ・ Low refractive index particles (hollow silica, average primary particle diameter 50 nm, manufactured by JGC Catalysts and Chemicals Co., Ltd.): 90 parts by mass (solid minute 100% conversion value)
・Methyl isobutyl ketone: 320 parts by mass

[Example 14]
An example in which the base material layer also serves as the first layer was used. A laminate was produced in the same manner as in Example 13, except that the following resin composition 8 for functional layer was used to form the second layer.

<Composition of the functional layer resin composition 8>
・Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name “Omnirad184”, manufactured by IGM Resins B.V.): 3 parts by mass ・Urethane acrylate (product name “EBECRYL8209”, manufactured by Daicel Ornex): 70 mass Part ・ Polyfunctional acrylate (product name “M-510”, manufactured by Toagosei Co., Ltd.): 30 parts by mass ・ Low refractive index particles (hollow silica, average primary particle diameter 50 nm, manufactured by JGC Catalysts and Chemicals Co., Ltd.): 190 parts by mass (solid minute 100% conversion value)
・Methyl isobutyl ketone: 340 parts by mass

[Example 15]
(1) Formation of 1st layer It carried out similarly to Example 1, and formed the 1st layer on the base material layer.

(2) Formation of Second Layer In the same manner as in Example 13, a second layer was formed on the first layer.

(3) Formation of Antifouling Layer In the same manner as in Example 1, an antifouling layer was formed on the second layer.

[Example 16]
A laminate was produced in the same manner as in Example 15, except that the second layer was formed using the functional layer resin composition 9 described below.

<Composition of Resin Composition 9 for Functional Layer>
・Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name “Omnirad184”, manufactured by IGM Resins B.V.): 3 parts by mass ・Urethane acrylate (product name “EBECRYL8209”, manufactured by Daicel Ornex): 72 mass Part ・ Polyfunctional acrylate (product name “M-510”, manufactured by Toagosei Co., Ltd.): 28 parts by mass ・ Low refractive index particles (hollow silica, average primary particle diameter 50 nm, manufactured by JGC Catalysts and Chemicals Co., Ltd.): 220 parts by mass (solid minute 100% conversion value)
・Methyl isobutyl ketone: 340 parts by mass

[Example 17]
(1) Formation of First Layer In the same manner as in Example 11, a first layer was formed on the substrate layer.

(2) Formation of Second Layer In the same manner as in Example 15, a second layer was formed on the first layer.

(3) Formation of Antifouling Layer In the same manner as in Example 1, an antifouling layer was formed on the second layer.

[Example 18]
An example in which the base material layer also serves as the first layer was used. A 50 μm-thick polyamideimide film (“CPI” manufactured by Kolon Co., Ltd.) was used as a base material that also serves as the first layer.

Next, a second layer was formed on the first layer in the same manner as in Example 1, except that the thickness of the second layer was 15 μm.

[Comparative Example 1]
The substrate layer used in Example 13 was designated as Comparative Example 1.

[Comparative Example 2]
An example in which the base material layer also serves as the first layer was used. A laminate was produced in the same manner as in Example 18, except that the functional layer resin composition 10 described below was used to form a second layer having a thickness of 3 μm.

<Composition of the functional layer resin composition 10>
・Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name “Omnirad184”, manufactured by IGM Resins B.V.): 3 parts by mass ・Urethane acrylate (product name “EBECRYL8209”, manufactured by Daicel Ornex): 72 mass Part ・ Polyfunctional acrylate (product name “M-510”, manufactured by Toagosei Co., Ltd.): 28 parts by mass ・ Low refractive index particles (hollow silica, average primary particle diameter 50 nm, manufactured by JGC Catalysts and Chemicals Co., Ltd.): 10 parts by mass (solid minute 100% conversion value)
・Methyl isobutyl ketone: 200 parts by mass

[Comparative Example 3]
An example in which the base material layer also serves as the first layer was used. A laminate was produced in the same manner as in Example 18, except that the functional layer resin composition 11 described below was used to form a second layer having a thickness of 3 μm.

<Composition of the functional layer resin composition 11>
・Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name “Omnirad184”, manufactured by IGM Resins B.V.): 3 parts by mass ・Urethane acrylate (product name “EBECRYL8209”, manufactured by Daicel Ornex): 88 mass Part ・ Polyfunctional acrylate (product name “M-510”, manufactured by Toagosei Co., Ltd.): 12 parts by mass ・ Low refractive index particles (hollow silica, average primary particle diameter 50 nm, manufactured by JGC Catalysts and Chemicals Co., Ltd.): 280 parts by mass (solid minute 100% conversion value)
・Methyl isobutyl ketone: 250 parts by mass

[Comparative Example 4]
A laminate was produced in the same manner as in Example 1, except that the first layer was formed using the functional layer resin composition 12 described below.

<Composition of the functional layer resin composition 12>
・Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name “Omnirad184”, manufactured by IGM Resins B.V.): 3 parts by mass ・Urethane acrylate (product name “8UX-047A”, manufactured by Taisei Fine Chemical Co., Ltd.): 20 Parts by mass ・Pentaerythritol tetraacrylate (product name “ATM-4E”, manufactured by Shin-Nakamura Chemical Co., Ltd.): 80 parts by mass ・Low refractive index particles (hollow silica, average primary particle diameter 50 nm, manufactured by JGC Shokubai Kasei Co., Ltd.): 30 mass Part (value converted to 100% solid content)
・Methyl isobutyl ketone: 200 parts by mass

[Comparative Example 5]
(1) Formation of First Layer A first layer was formed on the substrate layer in the same manner as in Example 1, except that the following resin composition 13 for functional layer was used.

<Composition of the functional layer resin composition 13>
・Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name “Omnirad184”, manufactured by IGM Resins B.V.): 3 parts by mass ・Urethane acrylate (product name “8UX-047A”, manufactured by Taisei Fine Chemical Co., Ltd.): 92 Parts by mass ・Pentaerythritol tetraacrylate (product name “ATM-4E”, manufactured by Shin-Nakamura Chemical Co., Ltd.): 8 parts by mass ・High refractive index particles (zirconia, average primary particle size 20 nm, manufactured by CIK Nanotech): 230 parts by mass ( 100% solid content conversion value)
・Methyl isobutyl ketone: 280 parts by mass

(2) Formation of Second Layer In the same manner as in Example 14, a second layer was formed on the first layer.

(3) Formation of Antifouling Layer In the same manner as in Example 1, an antifouling layer was formed on the second layer.

[Comparative Example 6]
(1) Formation of 1st layer It carried out similarly to Example 9, and formed the 1st layer on the base material layer.

(2) Formation of Second Layer A second layer was formed on the first layer in the same manner as in Example 13, except that the thickness was 40 nm.

(3) Formation of Antifouling Layer In the same manner as in Example 1, an antifouling layer was formed on the second layer.

[Comparative Example 7]
(1) Formation of First Layer A first layer was formed on the substrate layer in the same manner as in Example 1, except that the following resin composition 14 for functional layer was used.

<Composition of the functional layer resin composition 14>
・Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name “Omnirad184”, manufactured by IGM Resins B.V.): 3 parts by mass ・Urethane acrylate (product name “8UX-047A”, manufactured by Taisei Fine Chemical Co., Ltd.): 92 Parts by mass ・Pentaerythritol tetraacrylate (product name “ATM-4E”, manufactured by Shin-Nakamura Chemical Co., Ltd.): 8 parts by mass ・High refractive index particles (zirconia, average primary particle size 20 nm, manufactured by CIK Nanotech): 200 parts by mass ( 100% solid content conversion value)
・Methyl isobutyl ketone: 270 parts by mass

(2) Formation of Second Layer In the same manner as in Example 16, a second layer was formed on the first layer.

(3) Formation of Antifouling Layer In the same manner as in Example 1, an antifouling layer was formed on the second layer.

[Comparative Example 8]
(1) Formation of First Layer A first layer was formed on the substrate layer in the same manner as in Example 1, except that the following resin composition 15 for functional layer was used.

<Composition of the functional layer resin composition 15>
・Polymerization initiator (1-hydroxycyclohexylphenyl ketone, product name “Omnirad184”, manufactured by IGM Resins B.V.): 3 parts by mass ・Urethane acrylate (product name “8UX-047A”, manufactured by Taisei Fine Chemical Co., Ltd.): 46 Parts by mass ・Pentaerythritol tetraacrylate (product name “ATM-4E”, manufactured by Shin-Nakamura Chemical Co., Ltd.): 54 parts by mass ・Methyl isobutyl ketone: 200 parts by mass

(2) Formation of Second Layer In the same manner as in Example 13, a second layer was formed on the first layer.

(3) Formation of Antifouling Layer In the same manner as in Example 1, an antifouling layer was formed on the second layer.

[evaluation]
(1) Luminous reflectance The luminous reflectance was determined according to JIS Z8722:2009. From the reflection spectrum obtained by making light in the wavelength range of 380 nm or more and 780 nm or less incident on the second layer side surface of the laminate, in the 2 degree field of view with standard light C, the tristimulus value X in the XYZ color system , Y, and Z were obtained, and the value of Y was taken as the luminous reflectance. In the measurement of luminous reflectance, a spectrophotometer "UV-2600" manufactured by Shimadzu Corporation was used under the following conditions. In addition, in order to prevent back reflection, the luminous reflectance of the laminate was measured using a black vinyl tape (product name "Yamato vinyl tape NO200-19-21" manufactured by Yamato Co., Ltd., 19 mm wide) with a width larger than the measurement spot area. ) was attached to the back surface of the laminate, and then measured.

(Measurement condition)
・Field of view: 2°
・Illuminant: C
・Light source: tungsten halogen lamp ・Measurement wavelength: 0.5 nm interval in the range of 380 nm to 780 nm ・Scan speed: high speed ・Slit width: 5.0 nm
・S/R switching: Standard ・Auto zero: Performed at 550 nm after baseline scanning

(2) Yellowness Index The yellowness index (YI) was determined according to JIS K7373:2006. Specifically, using a UV-visible near-infrared spectrophotometer (manufactured by JASCO Corporation "V-7100"), by a spectrophotometric method, using a deuterium lamp and a tungsten halogen lamp, the range of 300 nm or more and 780 nm or less Based on the transmittance measured at intervals of 0.5 nm, the tristimulus values X, Y, and Z in the XYZ color system are obtained in the 2-degree field of view with standard light C, and the values of X, Y, and Z was calculated from the following formula. In addition, the yellowness index was measured under the following conditions.
YI=100(1.2769X−1.0592Z)/Y

(Measurement condition)
・Field of view: 2°
・Illuminant: C
・Light source: deuterium lamp and tungsten halogen lamp ・Measurement wavelength: 0.5 nm intervals in the range of 300 nm to 780 nm ・Scan speed: high speed ・Slit width: 5.0 nm
・S/R switching: Standard ・Auto zero: Performed at 550 nm after baseline scanning

(3) Dynamic bending resistance The following dynamic bending test was performed on the laminate to evaluate bending resistance. First, a laminate with a size of 50 mm × 200 mm was prepared, and as shown in FIG. A short side portion 1C of the body 1 and a short side portion 1D facing the short side portion 1C were fixed by fixing portions 51 arranged in parallel. Next, as shown in FIG. 4(b), the fixed portions 51 are moved closer to each other, thereby deforming the laminate for display device 1 so as to be folded, and furthermore, as shown in FIG. 4(c), Then, after moving the fixing portion 51 to a position where the distance d between the two opposing short side portions 1C and 1D fixed by the fixing portion 51 of the display device laminate 1 becomes a predetermined value, the fixing portion 51 is removed. Deformation of the display device laminate 1 was eliminated by moving in the opposite direction. By moving the fixing portion 51 as shown in FIGS. 4A to 4C, the stack 1 for a display device was repeatedly folded by 180°. At this time, the distance d between the two opposing short sides 1C and 1D of the display device laminate 1 was set to 10 mm. In addition, when the laminate was bent so that the second layer was on the inside, it was called inward bending, and when it was bent so that the second layer was on the outside, it was called outward bending. The results of the dynamic bending test were evaluated according to the following criteria.
A: The laminate did not crack or break even after 300,000 cycles.
B: Cracking or breakage occurred in the laminate by 300,000 cycles.

(4) Visibility After the above dynamic bending test was performed on the laminate, the position and bending direction of the bending portion of the laminate were aligned with the position and bending direction of the bendable display, and the lamination was performed. The laminate was adhered to the surface of a foldable display ("ThinkPad X1 Fold" manufactured by Lenovo) so that the surface on the second layer side of the body was the surface, and the visibility was confirmed. At this time, for example, the angle θ2 of the foldable display 20 as shown in FIG. 3 was set to 120°. The viewing direction was set at 60° to the normal to the surface of the first display region 22 of the foldable display 20 and to 15° to the normal to the surface of the second display region 23 .

For example, with regard to the visibility of the first display area 22 of the foldable display 20 as shown in FIG. 3, characters were displayed to confirm whether the characters could be visually recognized.

Further, for example, regarding the visibility of the first display area 22 and the second display area 23 of the foldable display 20 as shown in FIG. It was confirmed whether or not there was a sense of incompatibility when the second display area 23 was moved and viewed.

Also, regarding the visibility of the bent portion 21 of the foldable display 20 shown in FIG. 3, for example, an image was displayed to check whether the bent portion 21 and other regions looked strange.

The visibility of the first display area, the visibility of the first display area and the second display area, and the visibility of the bent portion were each checked and comprehensively evaluated according to the following criteria.
A: 10 out of 10 people could visually recognize the first display area, the first display area, the second display area, and the bent portion without any problem.
B: 7 or more and 9 or less out of 10 people could visually recognize the first display area, the first display area, the second display area, and the bent portion without any problem.
C: 4 or more and 6 or less out of 10 people could visually recognize the first display area, the first display area, the second display area, and the bent portion without any problem.
D: Of the 10 people, less than 4 people could see the first display area, the first display area, the second display area, and the bent portion without any problem.

In the laminates of Examples 1 to 18, the luminous reflectance of specularly reflected light at an incident angle of 60° is less than a predetermined value, and the yellowness YI1 of transmitted light in the direction of 60° and the transmission in the direction of 15° Since the absolute value of the difference in yellowness YI2 of light is equal to or less than a predetermined value, the visibility of the first display region and the visibility of the first display region and the second display region are good, and the foldable display is provided. Visibility was good in the mode of use in which an image was observed in a folded state. On the other hand, in the laminates of Comparative Examples 1 to 8, the luminous reflectance of specularly reflected light at an incident angle of 60 °, or the yellowness YI1 of transmitted light in the direction of 60 ° and the yellowness of transmitted light in the direction of 15 ° Since the absolute value of the difference of YI2 is not within the predetermined range, the visibility of the first display area or the visibility of the first display area and the second display area is poor, and the image is observed with the foldable display folded. The visibility was inferior in the usage pattern.

In addition, in the laminates of Examples 1 to 17, the thickness of the second layer was within the predetermined range, so the dynamic flexibility was good, and the visibility of the bent portion was also good.

REFERENCE SIGNS LIST 1... Laminate for display device 2... Base material layer 3... First layer 4... Second layer 5... Hard coat layer 6... Shock absorbing layer 7... Adhesive layer for attachment 8... Antifouling layer 30... Display device 31... Display panel

Claims (9)

A laminate for a display device having a substrate layer, a first layer, and a second layer in this order,
The luminous reflectance of specularly reflected light when light is incident on the second layer side surface of the display device laminate at an incident angle of 60° is 10.0% or less,
The yellowness YI1 of the transmitted light in the direction of 60° with respect to the normal to the second layer side surface of the display device laminate and the normal to the second layer side surface of the display device laminate In contrast, the absolute value of the difference between the yellowness index YI2 of the transmitted light in the direction of 15° and the yellowness index YI2 is 3.0 or less. The laminate for a display device according to claim 1, wherein the thickness of the second layer is 1 µm or more and 10 µm or less, and the refractive index of the second layer is 1.40 or more and 1.50 or less. 2. The method according to claim 1, wherein the thickness of the second layer is 50 nm or more and 1 μm or less, and the ratio of the refractive index of the first layer to the refractive index of the second layer is 1.05 or more and 1.20 or less. A laminate for a display device. The laminate for a display device according to any one of claims 1 to 3, wherein the base material layer also serves as the first layer. 5. The laminate for a display device according to any one of claims 1 to 4, further comprising a hard coat layer between the base material layer and the first layer. 6. Any one of claims 1 to 5, comprising a shock absorbing layer on the side of the substrate layer opposite to the first layer or between the substrate layer and the first layer. The laminate for a display device according to 1. 7. The laminate for a display device according to any one of claims 1 to 6, which has an adhesive layer for attachment on the side opposite to the first layer of the base material layer. 8. The display device laminate according to any one of claims 1 to 7, further comprising an antifouling layer on a surface of the second layer opposite to the first layer. a display panel;
a laminate for a display device according to any one of claims 1 to 8, which is arranged on the viewer side of the display panel;
A display device.

Images