CN112867980A

CN112867980A - Optical laminate and method for producing same

Info

Publication number: CN112867980A
Application number: CN201980066881.8A
Authority: CN
Inventors: 沈载镐
Original assignee: Sumitomo Chemical Co Ltd
Current assignee: Sumitomo Chemical Co Ltd
Priority date: 2018-10-12
Filing date: 2019-09-03
Publication date: 2021-05-28
Also published as: TW202019686A; JP2020061063A; KR20210071969A; WO2020075420A1

Abstract

The invention provides an optical laminate which is provided with a colored layer with good shielding performance and adjusts the degree of whiteness of the colored layer and a manufacturing method thereof. The optical laminate comprises a front plate, a bonding layer, and a back plate in this order, and further comprises a colored layer provided on a part of the front plate-side surface of the back plate. The front panel side surface of the colored layer has an arithmetic mean roughness Ra1 of 0.15 [ mu ] m or less and the colored layer has an optical density of 5 or more.

Description

Optical laminate and method for producing same

Technical Field

The present invention relates to an optical laminate and a method for manufacturing the same.

Background

In various image display devices such as liquid crystal display devices and organic Electroluminescence (EL) display devices, a front panel is sometimes provided on the visible side of a display panel in order to protect the display panel. In some cases, a non-display region is provided in such a front panel in order to shield electrodes, wirings, and the like, or to suppress light leakage of light leaking from the display panel side (for example, patent documents 1 and 2). Patent documents 1 and 2 describe forming a non-display region as a colored layer.

Documents of the prior art

Patent document

Patent document 1: korean laid-open patent No. 10-2015-0042046

Patent document 2: korean laid-open patent No. 10-2017-0039809

Patent document 3: korean laid-open patent No. 10-2008-0055335.

Disclosure of Invention

When the non-display region is formed as a colored layer, it is necessary to form the colored layer so as to be capable of shielding an electrode, a wiring, and the like and to have sufficient shielding properties to suppress light leakage. The non-display region may be provided on the front panel side of the display panel, not on the front panel. The present inventors have found that, in this case, even if the concentration of the colorant in the colored layer is increased in order to form a colored layer having sufficient shading properties, the colored layer turns white and a desired color tone cannot be obtained. For example, in the case of forming a black colored layer, even if the concentration of the black coloring agent is increased, the black colored layer is not formed, but a gray colored layer is formed.

The invention aims to provide an optical laminate which is provided with a colored layer with good shielding performance and adjusts the whiteness degree of the colored layer and a manufacturing method thereof.

The invention provides the following optical laminate and a method for manufacturing the same.

[ 1] an optical laminate comprising a front plate, a bonding layer and a back plate in this order,

a coloring layer provided on a part of the front panel side surface of the rear panel,

the front panel side surface of the colored layer has an arithmetic mean roughness Ra1 of 0.15 [ mu ] m or less,

the colored layer has an optical density of 5 or more.

The optical laminate according to [ 1], wherein the arithmetic average roughness Ra1 is 0.1 μm or less.

The optical laminate according to [ 1] or [ 2], wherein the colored layer includes a1 st layer disposed on the outermost surface of the front panel side and a2 nd layer disposed closer to the rear panel side than the 1 st layer.

The optical laminate according to [ 4 ] or [ 3 ], wherein the arithmetic average roughness Ra2 of the front-plate-side surface of the 2 nd layer is larger than the arithmetic average roughness Ra 1.

[ 5 ] the optical laminate according to [ 3 ] or [ 4 ], wherein the 2 nd layer contains a colorant,

the colorant contains at least a pigment.

The optical laminate according to [ 5 ], wherein the concentration of the pigment in the 2 nd layer is higher than the concentration of the pigment in the 1 st layer.

The optical laminate according to [ 6 ], wherein the thickness of the 1 st layer is smaller than the thickness of the 2 nd layer.

The optical laminate according to any one of [ 5 ] to [ 7 ], wherein the pigment is a black pigment.

The optical laminate according to any one of [ 1] to [ 8 ], wherein the colored layer is provided on at least a part of an edge portion of the optical laminate.

The optical laminate according to any one of [ 1] to [ 9 ], wherein the back sheet includes at least one of a polarizing plate and a touch sensor panel.

[ 11 ] A method for producing an optical laminate according to any one of [ 1] to [ 10 ],

the method comprises a step of forming the colored layer on the back plate by screen printing.

[ 12 ] the method for producing an optical laminate according to [ 11 ], wherein the colored layer includes a1 st layer disposed on the outermost surface of the front panel side and a2 nd layer disposed closer to the rear panel side than the 1 st layer,

the step of forming the colored layer includes a step of forming the 2 nd layer on one surface side of the rear plate by screen printing; and forming the layer 1 on a side opposite to the back plate of the layer 2 by screen printing.

According to the present invention, it is possible to provide an optical laminate which has a colored layer having excellent shielding properties and in which the degree of whiteness of the colored layer is adjusted.

Drawings

Fig. 1 is a schematic cross-sectional view schematically showing an example of an optical laminate according to the present invention.

Fig. 2 is a schematic plan view of the optical layered body shown in fig. 1, as viewed from the front panel side.

Fig. 3(a) to (e) are cross-sectional views schematically showing a method for producing an optical laminate of the present invention.

Fig. 4 is a schematic cross-sectional view schematically showing an example of an image display device including the optical laminate of the present invention.

Fig. 5(a) and (b) are schematic views showing examples of the bending form of the image display device.

Fig. 6 is a schematic cross-sectional view schematically showing another example of an image display device including the optical laminate of the present invention.

Fig. 7 is a schematic cross-sectional view schematically showing another example of an image display device including the optical laminate of the present invention.

Fig. 8 is a schematic cross-sectional view schematically showing another example of an image display device including the optical laminate of the present invention.

Fig. 9 is a schematic cross-sectional view schematically showing another example of an image display device including the optical laminate of the present invention.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings, and the present invention is not limited to the following embodiments. In all the following drawings, in order to facilitate understanding of each component, a scale is appropriately adjusted to indicate that the scale of each component shown in the drawings does not coincide with the scale of an actual component.

(optical laminate)

Fig. 1 is a schematic cross-sectional view schematically showing an example of an optical laminate according to the present embodiment. Fig. 2 is a schematic plan view of the optical layered body shown in fig. 1, as viewed from the front panel side. The optical laminate 100 includes a front plate 10, a bonding layer 20, and a back plate 30 in this order from the visible side. The optical laminate 100 further includes a colored layer 40, and the colored layer 40 is provided on a part of the front surface 10 side surface of the back surface plate 30. The colored layer 40 may be in direct contact with the laminating layer 20. The optical laminate 100 can constitute an image display device as described later.

The optical stack 100 is preferably bendable. The optical laminate 100 can be bent, and thus can be used for an image display device (flexible display) that can be bent, wound, or the like.

The shape of the optical laminate 100 in the plane direction is not particularly limited, but is preferably a square shape, and more preferably a rectangular shape. When the optical laminate 100 has a rectangular shape, the length of the long side is preferably 50mm to 300mm, and may be 100mm to 280mm, and the length of the short side is, for example, preferably 30mm to 250mm, and may be 60mm to 220 mm. The optical laminate 100 may have a rounded square shape in which at least one of the corners of the square shape is R-processed, or may have a square shape having a cutout on at least one side. Further, the optical laminate 100 may be provided with a hole penetrating in the lamination direction.

The thickness of the optical laminate 100 is not particularly limited, and is preferably 40 μm to 300 μm, and may be 70 μm to 200 μm. The thickness of the optical laminate 100 can be adjusted by the functions of the front plate 10 and the back plate 30.

(colored layer)

The colored layer 40 is not limited in arrangement position, shape, color, and the like in the facing direction as long as it is provided on a part of the front panel 10 side surface of the back panel 30. The colored layer 40 is preferably provided on at least a part of an edge portion in the surface direction orthogonal to the lamination direction of the optical laminate 100, and may be provided on the entire edge portion in the surface direction of the optical laminate 100 as shown in fig. 2. By providing the colored layer 40 so as to surround the edge portion of the optical layered body 100, the colored layer 40 is made visible like a frame, and therefore, the design can be improved.

The optical laminate 100 may be divided into a display region a and a non-display region B in a plane direction orthogonal to the lamination direction thereof, and in this case, as shown in fig. 1, it is preferable to provide a colored layer 40 in the non-display region B. As will be described later, when the optical layered body 100 constitutes an image display device, the display region a of the optical layered body 100 is a region where an image is displayed, and the non-display region B is a region where an image is not displayed. Accordingly, in the non-display region B, it is sometimes required to dispose electrodes, wirings, and the like or to suppress light leakage from a display unit provided in the image display device. In this case, the colored layer 40 provided in the non-display region B preferably has sufficient shielding properties to the extent that it can conceal electrodes, wirings, and the like and suppress light leakage.

The colored layer 40 may have a layer structure of 1 layer, or may have a multilayer structure of 2 or more layers in the stacking direction. When the colored layer 40 has 2 or more layers, the layers may be in contact with each other in the stacking direction. For example, as shown in fig. 1, the colored layer 40 may have a 2-layer structure including a1 st layer 40a disposed on the outermost surface of the front panel 10 side and a2 nd layer 40b disposed on the back panel 30 side with respect to the 1 st layer 40 a. When the colored layer 40 has a multilayer structure of 2 or more layers, each layer can be distinguished according to the type and content of the colorant, the arithmetic average roughness on the front panel 10 side, the color tone, and the like.

The colored layer 40 has an arithmetic average roughness Ra1 of 0.15 μm or less, preferably 0.12 μm or less, more preferably 0.1 μm or less, and may be 0.08 μm or less, and usually 0.01 μm or more on the front panel 10 side surface. In the case where the colored layer 40 shown in fig. 1 has the 1 st layer 40a and the 2 nd layer 40b, the arithmetic average roughness Ra1 of the front panel 10 side surface of the colored layer 40 becomes the arithmetic average roughness of the front panel 10 side surface of the 1 st layer 40a disposed on the outermost surface of the front panel 10. The arithmetic mean roughness can be measured by the method described in the examples described below. The arithmetic average roughness Ra1 of the colored layer 40 can be adjusted according to the kind and content of a colorant (for example, a pigment) and an additive contained in the colored layer 40, the method of forming the colored layer 40, the method of drying ink or paint after application, and the like.

Since the colored layer 40 is provided on the back surface plate 30 in the optical laminate 100, when the colored layer 40 is viewed from the visible side of the optical laminate 100 through the front surface plate 10 and the adhesive layer 20, the surface of the colored layer 40 on the front surface plate 10 side can be seen. The larger the arithmetic average roughness Ra1 on the front panel 10 side surface of the colored layer 40, the more easily the light is scattered on the surface of the colored layer 40, and therefore the colored layer 40 is likely to be a white color tone. By setting the arithmetic average roughness Ra1 of the surface of the colored layer 40 on the front panel 10 (the arithmetic average roughness of the surface of the 1 st layer 40a on the front panel 10) to 0.15 μm or less as described above, the whiteness degree of the colored layer 40 can be adjusted to an excessive whiteness degree, and the color modulation of the colored layer 40 recognized from the front panel 10 side of the optical laminate 100 can be improved. Further, by setting the arithmetic average roughness Ra1 of the surface of the colored layer 40 on the front panel 10 side to 0.1 μm or less, the degree of whiteness of the colored layer 40 can be further suppressed from being recognized. By controlling the arithmetic average roughness Ra1 of the surface of the colored layer 40 in this way, the colored layer 40 can be adjusted to a desired color tone ranging from, for example, black with a gray tint to black according to the specifications of the product.

The optical density of the colored layer 40 is 5 or more, and may be 5.05 or more, or may be 5.10 or more. The optical density of the colored layer 40 can be measured by the method described in the examples described later. As the optical density of the colored layer 40 increases, the shielding property of the colored layer 40 increases, whereby the shielding property of the electrode and the wiring is easily improved, and light leakage from the display unit is easily suppressed. The optical density of the colored layer 40 can be adjusted according to the kind and content of the colorant contained in the colored layer 40, the thickness of the colored layer 40, and the like.

The colored layer 40 may contain a colorant, which may be a pigment or a dye, and the colored layer 40 may contain 1 or 2 or more colorants. Examples of the colorant include carbon black such as acetylene black, inorganic pigments such as iron black, titanium dioxide, zinc white, valve stem, chrome vermilion, cobalt blue, yellow lead, and titanium yellow; organic pigments or dyes such as phthalocyanine blue, indanthrone blue, isoindigo yellow, benzidine yellow, quinacridone red, polyazo red, perylene red, aniline black, and the like; metallic pigments made of scaly foils of aluminum, brass, and the like; and pearl luster pigments (pearl pigments) comprising scaly foils such as titanium dioxide-coated mica and basic lead carbonate.

When the colorant contains a pigment, the pigment preferably has an arithmetic average particle diameter of 1nm to 500nm, preferably 10nm to 100nm, more preferably 10nm to 70nm, and may be 32nm to 52 nm. The particle size distribution is, for example, 10nm to 400 nm. The arithmetic mean particle diameter and particle size distribution of the pigment can be calculated based on the particle diameter of 100 particles arbitrarily measured by imaging the pigment to be measured with an electron microscope (for example, "SU 8010" manufactured by Hitachi High-Technologies, ltd.) and using the obtained image, and the arithmetic mean particle diameter can be calculated from the average value of 100 measured particle diameters.

When the colorant contained in the colored layer 40 contains a pigment, the arithmetic average roughness of the surface of the colored layer 40 tends to increase. Thus, when the colored layer 40 contains a pigment, the arithmetic average roughness Ra1 of the surface of the colored layer 40 and the optical density of the colored layer 40 are set to the above ranges, whereby a good light-shielding property can be obtained while suppressing the whiteness degree of the colored layer 40. Further, in the case where the pigment contained in the colored layer 40 is a black pigment such as carbon black, since a color change when the colored layer 40 is white becomes remarkable, in the case where the colored layer 40 contains a black pigment, it is preferable that the arithmetic average roughness Ra1 and the optical density be in the above-mentioned ranges.

When the colored layer 40 has a multilayer structure of 2 or more layers, the kind and concentration of the colorant contained in each layer are not particularly limited, and may be the same or different from each other.

When the colored layer 40 includes the 1 st layer 40a and the 2 nd layer 40b and the colored layer 40 includes a pigment, at least the 2 nd layer 40b preferably includes a pigment. The 1 st layer 40a may or may not contain a pigment, and the concentration of the pigment in the 2 nd layer 40b is preferably larger than that of the 1 st layer 40 a. When the pigment concentration of the layer containing the pigment is increased, the color of the layer can be thickened to improve the masking property, and the arithmetic mean roughness of the surface of the layer is likely to increase. On the other hand, when the pigment concentration of the layer containing the pigment is reduced, the arithmetic mean roughness of the surface of the layer can be reduced, the color of the layer becomes thin, and the masking property is lowered. Thus, the pigment concentration of the 1 st layer 40a disposed on the outermost surface of the front plate 10 side is reduced, the arithmetic mean roughness Ra1 of the surface of the colored layer 40 on the front plate 10 side is reduced, the pigment concentration of the 2 nd layer 40b disposed closer to the rear plate 30 side than the 1 st layer 40a is increased, and the optical density of the colored layer 40 is increased, whereby the colored layer 40 can be adjusted to have a good shielding property and the whiteness of the colored layer 40 can be suppressed.

It is also possible to make the concentration of the pigment of the 2 nd layer 40b larger than that of the 1 st layer 40a and make the thickness of the 1 st layer 40a smaller than that of the 2 nd layer 40 b. When the concentration of the pigment contained in the 1 st layer 40a is low, the arithmetic mean roughness of the surface of the colored layer 40 is unlikely to increase even if the thickness of the 1 st layer 40a is reduced. In addition, by increasing the thickness of the 2 nd layer 40b having a high pigment concentration, the optical density of the colored layer 40 can be increased. Thus, by setting the relationship between the concentration and the thickness of the pigment in the 1 st layer 40a and the 2 nd layer 40b as described above, the whiteness of the colored layer 40 can be suppressed while the colored layer 40 is adjusted to have a good shielding property.

In the colored layer 40, the arithmetic average roughness Ra2 of the front panel 10 side surface of the 2 nd layer 40b is not particularly limited, and may be larger than the arithmetic average roughness Ra1 of the front panel 10 side surface of the colored layer 40 (the arithmetic average roughness of the front panel 10 side surface of the 1 st layer 40 a). As described above, when the concentration of the pigment in the 2 nd layer 40b is made higher than that of the pigment in the 1 st layer 40a, the arithmetic average roughness Ra2 tends to be higher than the arithmetic average roughness Ra 1. However, by providing the 1 st layer 40a on the front panel 10 side of the 2 nd layer 40b, light scattering on the front panel 10 side surface of the colored layer 40 can be suppressed, and thus the whiteness degree of the colored layer 40 can be adjusted to be suppressed.

The arithmetic average roughness Ra2 of the front panel 10-side surface of the 2 nd layer 40b is not particularly limited, and may be, for example, 0.12 μm or more, or more than 0.15 μm, or 0.17 μm or more, or 0.2 μm or more. The arithmetic average roughness Ra2 may be, for example, 0.5 μm or less.

The color of the colored layer 40 is not particularly limited, and may be appropriately selected depending on the application, design, and the like. Examples of the color of the colored layer 40 include black, red, dark purple, silver, and gold, and preferably a color other than white. When the colored layer 40 has a multilayer structure of 2 or more layers, the colors of the respective layers may be the same or different from each other.

The colored layer 40 may have a uniform thickness and a rectangular cross-sectional shape as shown in fig. 1, or the colored layer 40 may have a non-uniform thickness, for example, a cross-sectional shape having a tapered portion whose thickness becomes thinner toward the inside. By having the tapered portion, air mixing which is likely to occur during lamination can be suppressed.

The thickness of the colored layer 40 is preferably 30 μm or less, and more preferably 15 μm or less. By setting the thickness of the colored layer 40 within the above range, the durability of the optical layered body 100 when it is bent can be improved. The thickness of the colored layer 40 is preferably 3 μm or more, and more preferably 6 μm or more. When the thickness of the colored layer 40 is 3 μm or more, the shading property is improved, and the colored layer 40 is easily recognized, which contributes to improvement of the design property. When the thickness of the colored layer 40 is not uniform, the numerical range described above as the thickness of the colored layer 40 is defined as the maximum thickness of the colored layer 40.

The 1 st layer 40a and the 2 nd layer 40b may have a uniform thickness and a rectangular cross-sectional shape as shown in fig. 1, and the 1 st layer 40a and the 2 nd layer 40b may have a non-uniform thickness, for example, may have a cross-sectional shape having a tapered portion whose thickness becomes thinner toward the inside. The thickness and shape of the 1 st layer 40a and the 2 nd layer 40b may be the same or different from each other. However, the colored layer 40 preferably has a1 st layer 40a on the outermost surface on the front panel 10 side, and a2 nd layer 40b on the rear panel 30 side of the 1 st layer 40a, so that the 1 st layer 40a and the 2 nd layer 40b are stacked.

The thickness of the 1 st layer 40a is preferably 10 μm or less, more preferably 7 μm or less, and further preferably 5 μm or less. The thickness of the 2 nd layer 40b is preferably 27 μm or less, more preferably 25 μm or less, and may be 20 μm or less, or may be 15 μm or less. In the case where the thicknesses of the 1 st layer 40a and the 2 nd layer 40b are not uniform, the numerical range described as the thicknesses of the 1 st layer 40a and the 2 nd layer 40b is defined as the maximum thickness of the 1 st layer 40a and the 2 nd layer 40 b. The thickness of the 1 st layer 40a and the thickness of the 2 nd layer 40b may be, for example, 0.5 μm or more, respectively.

The width of the colored layer 40 (the length in the plane direction of the optical laminate 100) is not particularly limited, and may be appropriately selected based on the size, the application, the design, and the like of the optical laminate 100. As shown in fig. 2, when the colored layer 40 is formed at the edge portion of the optical layered body, the width of the colored layer 40 may be, for example, 0.5mm or more, or 3mm or more, or 5mm or more, or generally 80mm or less, or 60mm or less, or 50mm or less, or 30mm or less, or 20mm or less.

The colored layer 40 can be formed by a printing method using ink or paint, a vapor deposition method using powder of a metallic pigment, a method in which the colored layer 40 containing a metallic pigment is formed in advance and transferred, or the like. In addition, these methods may be combined. Colored layer 40 is preferably formed on the surface of back surface plate 30 by a printing method. Examples of the printing method include screen printing, gravure printing, offset printing, transfer from a transfer sheet, and inkjet printing. By repeating printing by a printing method, the colored layer 40 having a desired thickness can be formed. When the colored layer 40 has a multilayer structure, each layer may be formed by repeating any one of the above-described forming methods, or may be formed by combining the above-described forming methods. For example, the colored layer 40 having the 1 st layer 40a and the 2 nd layer 40b shown in fig. 1 may include a step of forming the 2 nd layer 40b on the surface of the back plate 30 by screen printing, and a step of forming the 1 st layer 40a on the side of the 2 nd layer 40b opposite to the back plate 30 side by screen printing.

The ink or paint for forming the colored layer 40 may contain a binder, a colorant, a solvent, an arbitrary additive, and the like. Examples of the binder include chlorinated polyolefins (e.g., chlorinated polyethylene and chlorinated polypropylene), polyester resins, polyurethane resins, acrylic resins, vinyl acetate resins, chlorinated ethylene-vinyl acetate copolymers, and cellulose resins. The binder resin may be used alone, or 2 or more kinds may be used in combination. The binder resin may be a thermally polymerizable resin or a photopolymerizable resin. When the colored layer 40 is formed by a printing method, it is preferable to use an ink or a paint in which the colorant is contained in an amount of 50 to 200 parts by mass with respect to 100 parts by mass of the binder resin.

In the case where the colored layer 40 has a multilayer structure of 2 or more layers, the binder components contained in the ink or paint for forming each layer are preferably the same. This can reduce the difference in refractive index between the respective layers of the colored layer 40.

In the above description, the case where the coloring layer 40 has a 2-layer structure has been mainly described, and the coloring layer may have a multilayer structure of 3 or more layers. For example, in the case where the colored layer 40 shown in fig. 1 further includes the 3 rd layer, the 3 rd layer may be provided between the 1 st layer 40a and the 2 nd layer 40b, or may be provided between the 2 nd layer 40b and the rear panel 30.

(front panel)

When the front panel 10 is a light-transmissive plate-like body, the material and thickness are not limited, and the plate-like body may have a single-layer structure or a multi-layer structure, and a glass plate-like body (e.g., a glass plate, a glass film, etc.) or a resin plate-like body (e.g., a resin plate, a resin sheet, a resin film, etc.) may be exemplified. The front panel 10 may be a layer constituting the outermost surface of the image display device.

As the glass plate, strengthened glass for display is preferably used. The thickness of the glass plate is, for example, 50 to 1000. mu.m. By using the glass plate, the front panel 10 having excellent mechanical strength and surface hardness can be constituted.

The resin film is not limited as long as it is a resin film that can transmit light. Examples of the film include films made of polymers such as triacetylcellulose, acetylcellulose butyrate, ethylene-vinyl acetate copolymer, propionylcellulose, butyrylcellulose, acetylpropionylcellulose, polyester, polystyrene, polyamide, polyetherimide, poly (meth) acrylic acid, polyimide, polyarylethersulfone, polysulfone, polyethylene, polypropylene, polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetal, polyetherketone, polyetheretherketone, polyarylethersulfone, polymethyl (meth) acrylate, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, and polyamideimide. These polymers may be used alone or in combination of 2 or more. When the image display device 300 is a flexible display, a resin film made of a polymer such as polyimide, polyamide, or polyamideimide, which can have excellent flexibility and can be configured to have high strength and high transparency, is preferably used.

The resin film may be a film in which a hard coat layer is provided on at least one surface of the base film to further increase the hardness. The hard coat layer may be formed on one surface of the substrate film or on both surfaces. In the case where the image display device described later is a touch panel type image display device, the surface of the front panel 10 is a touch surface, and therefore a resin film having a hard coat layer is preferably used. By providing the hard coat layer, a resin film having improved hardness and scratch resistance can be formed. The hard coat layer is a cured layer of, for example, an ultraviolet curable resin. Examples of the ultraviolet curable resin include (meth) acrylic resins, silicone resins, polyester resins, polyurethane resins, amide resins, and epoxy resins. The hard coating may contain additives for the purpose of improving strength. The additive is not limited, and examples thereof include inorganic fine particles, organic fine particles, or a mixture thereof. The thickness of the resin film is, for example, 30 to 2000. mu.m.

The front panel 10 may have a function as a touch sensor, a blue blocking function, a viewing angle adjusting function, and the like, instead of having only a function of protecting the front surface of the image display device.

(laminating layer)

The laminating layer 20 is a layer interposed between the front panel 10 and the back panel 30 and is a pressure-sensitive adhesive layer or an adhesive layer. The adhesive layer 20 is preferably an adhesive layer in view of absorbing the step difference generated by the colored layer 40 well. The extrusion material to be the adhesive layer 20 may be a material having a composition different from that of the binder component contained in the ink or paint forming the colored layer 40.

The pressure-sensitive adhesive layer may be composed of a pressure-sensitive adhesive composition containing a resin such as a (meth) acrylic, rubber, urethane, ester, silicone, or polyvinyl ether resin as a main component. Among these, preferred is an adhesive composition containing a (meth) acrylic resin having excellent transparency, durability, heat resistance, and the like as a base polymer. The adhesive composition may be an active energy beam-curable type or a heat-curable type.

As the (meth) acrylic resin (base polymer) used in the adhesive composition, for example, a polymer or copolymer using 1 or 2 or more kinds of (meth) acrylic esters such as butyl (meth) acrylate, ethyl (meth) acrylate, isooctyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate as monomers is preferably used. The base polymer is preferably copolymerized with a polar monomer. Examples of the polar monomer include monomers having a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group, and the like, such as (meth) acrylic acid, 2-hydroxypropyl (meth) acrylate, hydroxyethyl (meth) acrylate, amide (meth) acrylate, N-dimethylaminoethyl (meth) acrylate, and glycidyl (meth) acrylate.

The adhesive composition may contain only the above-mentioned base polymer, and may generally contain a crosslinking agent. Examples of the crosslinking agent include a polymer having a metal ion having a valence of 2 or more, that is, a metal carboxylate salt with a carboxyl group; polyamine compounds, i.e. forming amide bonds with carboxyl groups; polyepoxy compounds, polyols, i.e., polymers that form ester linkages with carboxyl groups; polyisocyanate compounds, i.e. polymers which form amide bonds with carboxyl groups. Among them, polyisocyanate compounds are preferable.

The active energy beam-curable adhesive composition is an adhesive composition having a property of being cured by irradiation with an active energy beam such as ultraviolet ray or electron beam, and having an adhesive property even before the irradiation with the active energy beam so as to be capable of being bonded to a coated cover such as a film, and the adhesive composition is cured by the irradiation with the active energy beam so as to be capable of adjusting the property of the bonding force. The active energy beam-curable adhesive composition is preferably an ultraviolet-curable adhesive composition. The active energy beam-curable adhesive composition further contains an active energy beam-polymerizable compound in addition to the base polymer and the crosslinking agent. Further, a photopolymerization initiator, a photosensitizer and the like are contained as necessary.

The binder composition may contain additives such as fine particles, beads (resin beads, glass beads, and the like), glass fibers, resins other than the base polymer, a tackifier, a filler (metal powder, other inorganic powder, and the like), an antioxidant, an ultraviolet absorber, a dye, a pigment, a colorant, an antifoaming agent, an anti-corrosion agent, and a photopolymerization initiator for imparting light scattering properties.

The organic solvent diluted solution of the adhesive composition may be coated on a substrate and dried to form the adhesive composition. In the case of using an active energy beam-curable pressure-sensitive adhesive composition, a cured product having a desired degree of curing can be formed by irradiating the pressure-sensitive adhesive layer formed with an active energy beam.

From the viewpoint of absorbing the step caused by the colored layer 40, the thickness of the adhesive layer 20 is preferably larger than the thickness of the colored layer 40, and is, for example, preferably 4 μm to 100 μm, and more preferably 5 μm to 50 μm.

(Back plate)

The material and thickness of the back plate 30 are not limited if it is a plate-like body that can transmit light, and it may be a single layer or a plurality of layers. The thickness of the back plate is preferably 50 μm to 1000 μm. The rear plate may not include a display unit described later.

As the back panel 30, a component used in a general image display device such as a polarizing plate or a touch sensor panel can be used. By using such components as the back plate 30, when the optical laminate 100 is used to form an image display device, the number of components of the image display device can be reduced, and the image display device can be made thinner. The back panel 30 is not limited to the polarizing plate and the touch sensor panel, and may be a protective film on the visible side of the polarizing plate, a laminate of the polarizing plate and the touch sensor panel, or the like.

As the rear panel 30, a glass plate (e.g., a glass plate, a glass film, etc.) or a resin plate (e.g., a resin plate, a resin sheet, a resin film, etc.) may be used as in the case of the front panel 10. As specific examples of the glass plate-like body and the resin plate-like body, the above description relating to the front panel 10 can be referred to.

(method for producing optical layered body)

Fig. 3 is a cross-sectional view schematically showing the method for manufacturing an optical laminate according to the present embodiment. The method for manufacturing the optical laminate 100 includes a step of preparing the back plate 30 (fig. 3 a), a step of forming the colored layer 40 on the surface of the back plate 30 (fig. 3 b), and a step of laminating the back plate 30 on which the colored layer 40 is formed, the adhesive layer 20, and the front plate 10 to obtain the optical laminate 100 (fig. 3 e). As a method for forming the colored layer 40, a printing method such as screen printing can be mentioned as described above.

The method may include a step of preparing the front panel 10 (fig. 3 c) and a step of providing the adhesive layer 20 on the surface of the front panel 10 (fig. 3 d) before the laminating step (fig. 3 e).

(image display device)

Fig. 4 is a schematic cross-sectional view schematically showing an example of an image display device including the optical laminate of the present embodiment. Fig. 5(a) and 5(b) are schematic views showing examples of the bending form of the image display device.

As shown in fig. 5, the image display device 300 includes: the optical laminate 100 includes a front plate 10 disposed on the front surface (visible side) thereof, and a display laminate 200 including a display unit, and the display laminate 200 is laminated on the back plate 30 side of the optical laminate 100.

The image display device 300 may be a flexible display panel. The image display device as a flexible display may be configured to be foldable with the visible-side surface being the inside as shown in fig. 5(a), or may be configured to be rollable as shown in fig. 5(b), for example.

The image display device 300 can be configured as a touch panel type image display device. The touch panel type image display device includes a touch sensor panel, and the front panel 10 included in the optical laminate 100 constitutes a touch surface.

Examples of the display unit included in the display laminate 200 include display units including display elements such as liquid crystal display elements, organic EL display elements, inorganic EL display elements, plasma display elements, and field emission type display elements.

The image display device can be used as a mobile device such as a smartphone or a tablet computer, a television, a digital camera, an electronic signboard, a measuring instrument, a counter, a business machine, a medical instrument, or the like. The image display device of the present embodiment includes the optical laminate, and the colored layer thereof has good shielding properties and the whiteness of the colored layer is suppressed as described above, so that the image display device can have a good appearance.

Specific examples of the image display device will be described with reference to fig. 6 to 9. Fig. 6 to 9 are schematic cross-sectional views schematically showing other examples of the image display device including the optical laminate of the present embodiment.

In the case where the image display device is the touch panel type liquid crystal display device 301 shown in fig. 6, the liquid crystal display device 301 may include the front panel 10, the adhesive layer 20, the polarizing plate 60a, the touch sensor panel 70, the liquid crystal display element unit 81, the polarizing plate 60b, and the backlight unit 90 in this order from the visible side. The liquid crystal display device 301 may include a colored layer 40 provided on a part of the polarizing plate 60a on the front panel 10 side surface. The liquid crystal display device 301 can be divided into a display region a and a non-display region B in the plane direction, and in this case, it is preferable to provide the colored layer 40 in the non-display region B.

In the liquid crystal display device 301, the laminate including the colored layer 40, which is composed of the front panel 10, the adhesive layer 20, and the polarizing plate 60a, is configured as an optical laminate 101, and the liquid crystal display device 301 is configured using the optical laminate 101. In the present embodiment, the polarizing plate 60a also functions as the back panel 30 of the optical laminate 101.

The touch panel liquid crystal display device may be a liquid crystal display device 302 shown in fig. 7 instead of the liquid crystal display device 301 shown in fig. 6. The liquid crystal display device 302 is different from the liquid crystal display device 301 shown in fig. 6 only in that the position where the polarizing plate 60a and the touch sensor panel 70 are stacked is replaced, and the colored layer 40 is provided on the front panel 10 side surface of the touch sensor panel 70.

In the liquid crystal display device 302, a laminate including the front panel 10, the adhesive layer 20, and the touch sensor panel 70 and including the colored layers 40 is configured as an optical laminate 102, and the liquid crystal display device 302 is configured using the optical laminate 102. In the present embodiment, the touch sensor panel 70 also functions as the back surface plate 30 of the optical layered body 102.

In the case where the image display device is a touch panel type organic EL display device 303 as shown in fig. 8, the organic EL display device 303 may include the front panel 10, the adhesive layer 20, the polarizing plate 60c, the touch sensor panel 70, and the organic EL unit 82 in this order from the visible side. The organic EL display device 303 may include a colored layer 40 provided on a part of the front panel 10-side surface of the polarizing plate 60 c. The organic EL display device 303 may be divided into a display region a and a non-display region B in the plane direction, and in this case, the non-display region B is preferably provided with the colored layer 40.

In the organic EL display device 303, a laminate including the front panel 10, the adhesive layer 20, and the polarizing plate 60c and including the color layer 40 is configured as an optical laminate 103, and the organic EL display device 303 is configured using the optical laminate 103. In the present embodiment, the polarizing plate 60c can also function as the back panel 30 of the optical layered body 103.

In the organic EL display device of the touch panel system, an organic EL display device 304 shown in fig. 9 may be used instead of the organic EL display device 303 shown in fig. 8. The organic EL display device 304 is different from the organic EL display device 303 shown in fig. 8 only in that the position where the polarizing plate 60c and the touch sensor panel 70 are stacked is replaced, and the coloring layer 40 is provided on the front panel 10 side surface of the touch sensor panel 70.

In the organic EL display device 304, a laminate including the front panel 10, the adhesive layer 20, and the touch sensor panel 70 and including the colored layers 40 is configured as an optical laminate 104, and the organic EL display device 304 is configured using the optical laminate 104. In the present embodiment, the touch sensor panel 70 also functions as the back surface plate 30 of the optical layered body 104.

(polarizing plate)

Examples of the polarizing plate include a stretched film obtained by adsorbing a dye having absorption anisotropy, a film obtained by applying a dye having absorption anisotropy and curing the applied dye, and the like as a polarizer.

Examples of the dye having absorption anisotropy include dichromatic dyes. Specific examples of the dichromatic dye include iodine and dichromatic organic dyes. The dichromatic organic dye includes a dichromatic direct dye composed of a bisazo compound such as c.i. direct RED 39, and a dichromatic direct dye composed of a compound such as triazole or tetrazole. Examples of the film coated with the dye having absorption anisotropy used as a polarizer include a stretched film obtained by adsorbing the dye having absorption anisotropy, a film coated with a composition containing a dichroic dye having liquid crystallinity or a composition containing a dichroic dye and a polymerizable liquid crystal and cured, and the like. A film obtained by coating and curing a dye having absorption anisotropy is preferable because the bending direction is not limited as compared with a stretched film obtained by adsorbing a dye having absorption anisotropy.

(1) Polarizing plate having stretched film as polarizer

A polarizing plate including a polarizer made of a stretched film in which a dye having absorption anisotropy is adsorbed will be described. A stretched film obtained by adsorbing a dye having absorption anisotropy as a polarizer is usually subjected to a step of uniaxially stretching a polyvinyl alcohol resin film; a step of dyeing a polyvinyl alcohol resin film with a dichromatic pigment to adsorb the dichromatic pigment; and a step of treating the polyvinyl alcohol resin film having the dichromatic pigment adsorbed thereon with an aqueous boric acid solution; and a step of treating with an aqueous boric acid solution and then washing with water. The polarizer may be used as it is, or a polarizer obtained by laminating a transparent protective film on one or both surfaces thereof may be used. The thickness of the polarizer thus obtained is preferably 2 μm to 40 μm, and more preferably 3 μm to 15 μm.

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

The saponification degree of the polyvinyl alcohol resin is usually about 85 to 100 mol%, and preferably 98 mol% or more. The polyvinyl alcohol resin may be modified, and for example, polyvinyl formaldehyde or polyvinyl acetal modified with aldehydes may be used. The polymerization degree of the polyvinyl alcohol resin is usually about 1000 to 10000, and preferably in the range of 1500 to 5000.

The polyvinyl alcohol resin is used as a raw material film for a polarizing plate. The method for forming the film of the polyvinyl alcohol resin is not particularly limited, and a known method can be used to form the film. The thickness of the polyvinyl alcohol-based raw material film may be, for example, about 10 μm to 150 μm.

The uniaxial stretching of the polyvinyl alcohol resin film may be performed before, simultaneously with, or after the dyeing with the dichromatic pigment. In the case of uniaxial stretching after dyeing, the uniaxial stretching may be performed before boric acid treatment or may be performed during boric acid treatment. In addition, uniaxial stretching can be performed in these plural stages. In the case of uniaxial stretching, the stretching may be performed uniaxially between rolls having different peripheral speeds, or may be performed uniaxially by using a heat roll. The uniaxial stretching may be dry stretching in which stretching is performed in the air, or wet stretching in which stretching is performed in a state where the polyvinyl alcohol resin film is swollen with a solvent. The draw ratio is usually about 3 to 8 times.

The material of the protective film to be bonded to one surface or both surfaces of the polarizer is not particularly limited, and examples thereof include films known in the art, such as a cyclic polyolefin resin film, an acetate resin film made of a resin such as triacetyl cellulose or diacetyl cellulose, a polyester resin film made of a resin such as polyethylene terephthalate, or polybutylene terephthalate, a polycarbonate resin film, a (meth) acrylic resin film, and a polypropylene resin film. From the viewpoint of light thinning, the thickness of the protective film is usually 300 μm or less, preferably 200 μm or less, more preferably 100 μm or less, and usually 5 μm or more, preferably 20 μm or more. The protective film may or may not have a phase difference.

(2) Polarizing plate having polarizer formed of film formed of liquid crystal layer

A polarizing plate including a film formed of a liquid crystal layer as a polarizer will be described. Examples of the film used as a polarizer and coated with a dye having absorption anisotropy include a film obtained by coating a composition containing a dichromatic dye having liquid crystallinity or a composition containing a dichromatic dye and a liquid crystal compound on a substrate and curing the coating. The film may be used as a release substrate or a substrate polarizing plate, or may be used as a polarizing plate having a structure in which a protective film is provided on one surface or both surfaces thereof. Examples of the protective film include those similar to polarizing plates provided with the stretched film as a polarizer.

The film obtained by curing the pigment having absorption anisotropy is preferably thin, but the thin film tends to decrease the strength and deteriorate the processability. The thickness of the film is usually 20 μm or less, preferably 5 μm or less, and more preferably 0.5 to 3 μm.

Specific examples of the film coated with the dye having the absorption anisotropy include films described in japanese patent application laid-open nos. 2013-37353 and 2013-33249.

The polarizing plate may further include a retardation film. The retardation film may include 1 or 2 or more retardation layers. The phase difference layer may be a potential a plate such as a λ/4 plate or a λ/2 plate, or a potential C plate. The retardation layer may be formed of a resin film obtained by exemplifying the material of the above-described protective film, or may be formed of a layer obtained by curing a polymerizable liquid crystal compound. The retardation film may further include an alignment film and a substrate film. The polarizer may be a circular polarizer.

(touch sensor panel)

As the touch sensor panel, if a touched position can be detected, the detection method is not limited, and a touch sensor panel such as a resistive film method, a capacitive coupling method, an optical sensor method, an ultrasonic wave method, an electromagnetic guide coupling method, a surface acoustic wave method, or the like can be exemplified. Since the cost is low, a touch sensor panel of a resistive film type or a capacitive coupling type is preferably used.

An example of a resistive touch sensor panel includes a pair of substrates arranged to face each other, an insulating spacer sandwiched between the pair of substrates, a transparent conductive film provided as a resistive film on the inner front surface of each substrate, and a touch position detection circuit. In an image display device provided with a resistive touch sensor panel, when the surface of the front panel 10 is touched, the opposing resistive films are short-circuited, and a current flows through the resistive films. The touch position detection circuit detects a change in voltage at that time, and detects the touched position.

An example of a capacitive touch sensor panel includes a substrate, a position detection transparent electrode provided on the entire surface of the substrate, and a touch position detection circuit. In an image display device provided with a capacitive touch sensor panel, when the surface of the front panel 10 is touched, the transparent electrode is grounded at the touched point via the capacitance of the human body. The touch position detection circuit detects grounding of the transparent electrode and detects a touched position.

Examples

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

[ measurement of arithmetic average roughness ]

The surface of the 2 nd layer formed on the TAC surface of the polarizer opposite to the polarizer side and the surface of the 1 st layer formed on the 2 nd layer opposite to the 2 nd layer side were measured for arithmetic mean roughness using a disturbing microscope (Bruker, Contour GT).

[ measurement of optical Density ]

Samples each composed of a layer of "substrate/colored layer" in which colored layers were formed on a substrate (polarizing plate produced in example 1) in the same order as in each example and comparative example were prepared, and each sample was cut into 5cm × 5cm to be used as a measurement sample for optical density measurement in each example and comparative example. The measurement specimen was set in an optical density measuring instrument (product name: 361T, manufactured by X-ray), a light source located above the colored layer side of the measurement specimen was turned on, the colored layer of the measurement specimen was focused, the light source located above was turned off, a light source for measurement located above the base material side of the measurement specimen was turned on, and the colored layer was set as a measurement region to measure the optical density. The results are shown in Table 2.

[ measurement of the thickness of the colored layer and the layer to be the colored layer ]

The thickness of the colored layer and each layer to be the colored layer was measured using an electron microscope ("SU 8010" manufactured by Hitachi High-Technologies).

[ visual observation of optical layered body ]

The three-wavelength lamp was disposed at a distance of about 200mm from the polarizer side of the optical laminate, light from the three-wavelength lamp was made incident on the optical laminate from the polarizer side, and the color and the state of transmission of the colored layer were visually confirmed from the window film side with the adhesive layer of the optical laminate.

[ example 1]

(production of Window film with adhesive layer)

A window film having a thickness of 70 μm (50 μm for the base film, 10 μm for each hard coat layer, and 270mm in the vertical direction × 250mm in the horizontal direction) in which hard coat layers were formed on both surfaces of the base film was prepared as a front panel (FIG. 3(c)), and a (meth) acrylic pressure-sensitive adhesive layer (25 μm in thickness, 270mm in the vertical direction × 250mm in the horizontal direction) was prepared as a pressure-sensitive adhesive layer. The base film of the window film is a polyimide-based resin film, and the hard coat layer is a layer formed from a composition containing a dendritic compound having a polyfunctional acrylic group at the terminal. Then, corona treatment was applied to the bonding surface between the window film and the adhesive layer and the bonding surface between the adhesive layer and the window film. Further, the window film was laminated with an adhesive layer to obtain a window film with an adhesive layer (fig. 3 (d)).

(production of polarizing plate)

After a photo-alignment film was formed on a triacetyl cellulose (TAC) film having a thickness of 25 μm, a composition containing a dichromatic dye and a polymerizable liquid crystal compound was applied to a substrate, and the composition was aligned and cured to obtain a polarizer having a thickness of 2.5 μm. This polarizer was coated with an acrylic resin composition and cured to obtain an overcoat layer having a thickness of 1 μm. On the overcoat layer, a retardation film (thickness 16 μm, layer structure: λ/4 plate (thickness 3 μm) composed of adhesive layer (thickness 5 μm)/layer obtained by curing liquid crystal compound and alignment film/adhesive layer (thickness 5 μm)/positive C-plate (thickness 3 μm) composed of layer obtained by curing liquid crystal compound and alignment film) including a layer obtained by polymerizing and curing liquid crystal compound was laminated. The polarizing plate thus obtained (layer structure of "TAC/polarizer/retardation film") was formed to have a thickness of 44.5 μm, and a length of 270 mm. times.250 mm in width) (FIG. 3 (a)).

(formation of colored layer)

The surface of the TAC of the polarizing plate obtained above was subjected to screen printing using the following composition for forming the layer 2 (black) as an ink using a 460-mesh screen, and after drying, printing was performed with a coating thickness of 6 μm discharge, and the resultant was dried for 30 minutes to form the layer 2 including a printed layer having a thickness of 6 μm, a vertical dimension of 60mm × a horizontal dimension of 55mm in a part of the edge portion. Thereafter, as a manner of laminating on the surface (surface opposite to TAC) of the 2 nd layer, the following 1 st layer forming composition was used as ink, and printing was performed by screen printing using a 460-mesh screen so that the coating thickness after drying was 3 μm, and the 1 st layer consisting of a printing layer having a thickness of 3 μm, 60mm in the vertical direction × 55mm in the horizontal direction was formed on the formed 2 nd layer, and a colored layer having the 2 nd layer and the 1 st layer in this order from the polarizer side was formed. When forming the colored layer, the arithmetic mean roughness of each layer was measured.

The results are shown in Table 2.

(preparation of layer-Forming composition 1)

The following ink components were added by 10 parts by mass of a curing agent and 10 parts by mass of a solvent to 100 parts by mass of the ink components, and the mixture was stirred at room temperature to obtain a composition for forming the layer 1. The pigment concentration of the ink component in the layer-forming composition 1 was 0% by mass.

[ ink Components ]

Ink compositions (H) shown in Table 1

[ curing agent ]

75% by mass of aliphatic polyisocyanate

25% by mass of ethyl acetate

[ solvent ]

Isofluorone

(preparation of layer-Forming composition 2)

The following ink components were added by 10 parts by mass of a curing agent and 10 parts by mass of a solvent, and the mixture was stirred at room temperature to obtain a composition for forming the 2 nd layer. The pigment concentration of the ink component in the layer-forming composition 2 was 10% by mass.

[ ink Components ]

Ink compositions (B) shown in Table 1

[ curing agent ]

75% by mass of aliphatic polyisocyanate

25% by mass of ethyl acetate

[ solvent ]

Isofluorone

(preparation of optical laminate)

Then, the surface of the window film with the pressure-sensitive adhesive layer and the surface of the colored layer on which the polarizing plate was formed were subjected to corona treatment, and the window film with the pressure-sensitive adhesive layer and the polarizing plate were laminated so that the corona-treated surface was located inside, and they were bonded together using a roll bonder and cured in an autoclave, whereby an optical laminate of example 1 was obtained (fig. 3 (e)). The optical layered body obtained was visually observed in the above-mentioned order, and as a result, it was black, and an object such as a three-wavelength lamp positioned on the polarizer side was not visible, and it was opaque.

[ examples 2 and 3 ]

Optical laminates of examples 2 and 3 were obtained in the same manner as in example 1 except that the ink components shown in tables 1 and 2 were used. The optical layered body obtained was visually observed in the above-mentioned order, and as a result, it was black, and an object such as a three-wavelength lamp positioned on the polarizer side was not visible, and it was opaque.

[ example 4 ]

An optical laminate of example 4 was obtained in the same manner as in example 1 except that the ink components shown in tables 1 and 2 were used to form the thicknesses of the colored layers shown in table 2. The optical layered body obtained was visually observed in the above-mentioned order, and as a result, it was grayish black, and an object such as a three-wavelength lamp on the polarizer side was not visible, and it was opaque.

[ example 5 ]

An optical laminate of example 4 was obtained in the same manner as in example 1 except that the 2 nd layer was not provided and the coloring layers of 1 layer were formed on the TAC surface of the polarizing plate using the ink components shown in table 1. The optical layered body obtained was visually observed in the above-mentioned order, and as a result, it was grayish black, and an object such as a three-wavelength lamp positioned on the polarizer side was not visible and was opaque.

[ example 6 ]

An optical laminate of example 6 was obtained in the same manner as in example 1 except that the ink components shown in tables 1 and 2 were used to form the thicknesses of the colored layers shown in table 2. The optical layered body thus obtained was visually observed in the above-mentioned order, and was gray black, and an object such as a three-wavelength lamp positioned on the polarizer side was not visible and was opaque.

[ comparative examples 1 and 2]

An optical laminate of comparative example 1 was obtained in the same manner as in example 1 except that the ink components shown in tables 1 and 2 were used to form the thicknesses of the colored layers shown in table 2. The optical layered body obtained was visually observed in the above-described order, and all of the results were grayish black, but objects such as a three-wavelength lamp positioned on the polarizer side were observed to be transparent.

[ comparative example 3 ]

An optical laminate of comparative example 3 was obtained in the same manner as in example 1 except that the ink components shown in tables 1 and 2 were used to form the thicknesses of the colored layers shown in table 2. The optical layered body obtained was visually observed in the above-mentioned order, and as a result, an object such as a three-wavelength lamp positioned on the polarizer side was not observed, and light was not transmitted, but the color tone was gray.

[ Table 1]

[ Table 2]

Description of the symbols

10 front panel, 20 laminating layer, 30 back panel, 40 coloring layer, 40a 1 st layer, 40b 2 nd layer, 60a, 60c polarizing plate, 70 touch sensor panel, 100, 101, 102, 103, 104 optical laminate, 200 display laminate, 300 image display device, 301, 302 liquid crystal display device, 303, 304 organic EL display device.

Claims

1. An optical laminate comprising a front plate, a bonding layer and a back plate in this order,

and a colored layer provided on a part of the front panel side surface of the rear panel,

the colored layer has an optical density of 5 or more.

2. The optical stack of claim 1,

the arithmetic average roughness Ra1 is 0.1 μm or less.

3. The optical stack of claim 1 or 2,

the colored layer includes a1 st layer disposed on the outermost surface of the front panel side and a2 nd layer disposed closer to the rear panel side than the 1 st layer.

4. The optical stack of claim 3,

the front panel-side surface of the 2 nd layer has an arithmetic average roughness Ra2 that is greater than the arithmetic average roughness Ra 1.

5. The optical stack of claim 3 or 4,

the 2 nd layer contains a colorant and is,

the colorant contains at least a pigment.

6. The optical stack of claim 5,

the concentration of the pigment of the 2 nd layer is greater than the concentration of the pigment of the 1 st layer.

7. The optical stack of claim 6,

the thickness of the 1 st layer is less than the thickness of the 2 nd layer.

8. The optical stack according to any one of claims 5 to 7,

the pigment is a black pigment.

9. The optical stack according to any one of claims 1 to 8,

the colored layer is provided on at least a part of the edge portion of the optical layered body.

10. The optical stack according to any one of claims 1 to 9,

the back panel includes at least one of a polarizing plate and a touch sensor panel.

11. A method for producing an optical laminate according to any one of claims 1 to 10,

12. The method for manufacturing an optical stack according to claim 11,

the colored layer includes a1 st layer disposed on the outermost surface of the front panel side and a2 nd layer disposed closer to the rear panel side than the 1 st layer,

the step of forming the colored layer includes: and a step of forming the 2 nd layer on one surface side of the back plate by screen printing, and a step of forming the 1 st layer on the opposite side of the 2 nd layer from the back plate by screen printing.