JP2001215308A - Anti-glare layer and optical member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To develop an anti-glare layer which can prevent reflection of outside view without degradation of image definition, and excellent in resistance to scuffing. SOLUTION: An optical member has an anti-glare layer consisting of a transparent resin layer having a thickness of 8 μm or more having a fine rugged structure on the surface in which an inequity height based on the top and the bottom is 0.5-1.5 μm, and the size of a projected part is 3-10 μm on basis of the diameter, and the average distance between the projected parts is 10-20 μm, and the anti-glare layer on at least one side of a transparent film base material, a polarizing plate, or an elliptically polarizing plate. Various kinds of display devices, such as a liquid crystal display device excellent in a display quality level without lowering the definition of an image with high definition by miniaturizing pixel size or the like, are obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-glare layer suitable for preventing reflection of an outside scene in various display devices.

[0002]

2. Description of the Related Art Conventionally, in various display devices such as a CRT, a plasma display, and a liquid crystal display device, the display device is provided on a surface of a screen or the like in order to prevent an image from being disturbed due to a scene reflected by external light of a fluorescent lamp. As the anti-glare layer to be formed, there has been known an anti-glare layer having various fine uneven surfaces so as to scatter and reflect external light. However, with the recent improvement in image quality due to the reduction in pixel size and the improvement in quality due to the use of flat panels, the conventional anti-glare layer has a large reduction in display quality such as coarse images, and the anti-glare layer with a finer grain Is required.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to develop an antiglare layer which can prevent reflection of an external scene without deteriorating image sharpness and has excellent scratch resistance.

[0004]

According to the present invention, the height of the unevenness based on the top and the valley is 0.5 to 1.5 μm, and the size of the convex is 3 to 10 μm based on the diameter. An antiglare layer comprising a transparent resin layer having a thickness of 8 μm or more having a fine uneven structure having an average distance of 10 to 20 μm on its surface, and a transparent film substrate, a polarizing plate, or elliptically polarized light comprising the antiglare layer. An optical member provided on at least one side of a plate is provided.

[0005]

According to the present invention, reflection of the outside scene can be effectively prevented without deteriorating the sharpness of a high-definition image due to downsizing of the pixel size and the like, and excellent abrasion resistance and excellent film strength can be obtained. As a result, it is possible to obtain an antiglare layer in which the surface is hardly damaged, and it is possible to obtain various display devices such as a liquid crystal display device having excellent display quality such as visibility by using an optical member to which the antiglare layer is applied.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The antiglare layer according to the present invention has a height of irregularities based on peaks and valleys of 0.5 to 1.5 μm,
It is composed of a transparent resin layer having a thickness of 8 μm or more and having a fine uneven structure on the surface, the size of the projections being 3 to 10 μm based on the diameter, and the average distance between the projections being 10 to 20 μm. Such an antiglare layer can be formed by a method of roughening the surface of the transparent resin layer to a predetermined state by an appropriate method such as embossing or buffing, but from the viewpoint of formation efficiency and the like, a transparent fine particle-containing transparent resin layer is formed. The method of forming with resin is preferable.

The transparent fine particles include, for example, silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide, and the like.
One or more kinds of appropriate ones that are insoluble in the resin used in combination, such as inorganic particles that may be conductive, organic particles made of a crosslinked or uncrosslinked polymer, or the like, can be used.
Particularly, those having excellent transparency are preferable. The average particle size of the transparent fine particles is 15 μm or less from the point of forming an anti-glare layer that can effectively prevent the reflection of the outside scene by forming a fine surface uneven structure that does not reduce the sharpness of high-definition images due to miniaturization of pixel size etc. , Especially 0.1 to 10 μm, especially 0.5 to
5 μm is preferred.

As the transparent resin for containing the transparent fine particles, one or two kinds of appropriate resins having excellent transparency and hardness can be used.
More than one species can be used. By the way, examples thereof include acetate resins and carbonate resins, arylate resins and sulfone resins, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polyether sulfone resins and polyamide resins, polyimide resins and styrene resins. Resins, olefin resins such as cyclic polyolefins, acrylic resins, fluorine resins, and resins which are cured by heat or ultraviolet rays such as acrylic, urethane, acrylic urethane, epoxy and silicone resins. Curable resins are preferably used from the viewpoint of abrasion resistance such as hard coat properties for the purpose of preventing surface scratches.

The formation of the antiglare layer using the transparent fine particles can be performed, for example, by forming a transparent resin containing the transparent fine particles into a film by an appropriate method such as an extrusion molding method, or by applying a liquid of the transparent resin containing the transparent fine particles and drying. In the case of a curable resin, use a method suitable for the resin type, such as a method in which transparent fine particles are blended with the monomer resin and applied, followed by a curing treatment. Can be. The amount of the transparent fine particles to be used can be appropriately determined in view of the anti-reflection property of the outside scene, but generally, the transparent resin 10
50 parts by weight or less per 0 parts by weight, preferably 2 to 40 parts by weight,
Particularly, it is 5 to 30 parts by weight.

According to the present invention, the anti-glare layer which can effectively prevent the reflection of the outside scene by forming a fine surface unevenness structure which does not degrade the sharpness of a high-definition image due to the reduction of the pixel size, etc. The height of the unevenness based on the top and the valley is 0.5 to 1.5 μm, and the size of the projection is 3 to 10 μm based on the diameter,
The surface has a fine uneven structure having an average distance between the protrusions of 10 to 20 μm. The height of the unevenness is less than 0.5 μm, the diameter of the projection is less than 3 μm, or the average distance between the projections is 20.
If it exceeds μm, the anti-glare effect will be poor, and if the height of the irregularities exceeds 1.5 μm, or if the diameter of the projection is 1
If it exceeds 0 μm, or the average distance between the projections is 10 μm
If it is less than 10, the sharpness of a high-definition image tends to be reduced.

[0011] A fine surface unevenness structure that is preferable from the viewpoint of the anti-glare effect and the maintenance of a fine image has a height of the above-mentioned unevenness of 0.7 to 1.4 µm, particularly 0.9 to 1.3 µm. The diameter of the projections is 4-9 μm, preferably 5-8 μm, and the average distance between the projections is 12-19 μm, especially 13
~ 18μm

The transparent resin layer needs to have a thickness of 8 μm or more. If the thickness is less than 8 μm, the film strength is insufficient and the scratch resistance is poor. The preferred thickness from the viewpoint of abrasion resistance and thinning is 30 μm or less, especially 25 μm or less, particularly 15 μm or less. In that case, it is preferable that the above-mentioned transparent fine particles are unevenly distributed on one side in contact with air as far as the quality of a clear image is not reduced.
Such an uneven distribution structure can be efficiently formed by a method using transparent fine particles having an apparent density smaller than that of the transparent resin.

The anti-glare layer may be provided directly on a display device to which the anti-glare layer is to be applied, may be provided directly on a member forming the display device such as a polarizing plate or an elliptically polarizing plate, or may be provided as an anti-glare sheet provided on the surface of a transparent film substrate. One or two or more layers can be provided at appropriate places on the surface of the display device or the like by an appropriate method such as a method of providing the display device directly or on a member forming the display device.

In the above, as the transparent film substrate supporting the antiglare layer, one or more of appropriate ones such as the transparent resin exemplified in the above antiglare layer can be used. There is no particular limitation. Above all, those made of a resin having excellent transparency, mechanical strength, heat stability, water resistance and the like are preferable.

The thickness of the transparent film substrate can be appropriately determined according to the strength and light transmittance. Generally 500 μm or less, especially 10-30
The thickness is 0 μm, especially 15 to 200 μm. The surface of the transparent film substrate may be subjected to an appropriate treatment such as a corona treatment, an ultraviolet irradiation treatment, a plasma treatment, a sputter etching treatment, an undercoat treatment, etc. for the purpose of improving the adhesion of a layer attached thereto. .

On the other hand, as a polarizing plate or an elliptically polarizing plate to which the above-mentioned antiglare layer is provided as an antiglare sheet as required, a polarizing film or a polarizing film protected by a transparent protective layer, and a retardation plate and a polarizing film laminated thereon are laminated. A suitable device used for forming a liquid crystal display device or the like can be used, and the type is not particularly limited.

Incidentally, as a specific example of the polarizing film, iodine and / or diamine is added to a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, and an ethylene / vinyl acetate copolymer-based partially saponified film. Examples thereof include stretched films obtained by adsorbing a chromatic dye, and oriented polyene films such as dehydrated polyvinyl alcohol and dehydrochlorinated polyvinyl chloride. The transparent protective layer provided as necessary on one side or both sides of the polarizing film is formed by using an appropriate material such as the transparent resin exemplified in the above anti-glare layer, and applying an appropriate method such as a coating method or a laminating method of a film. Can be formed.

Examples of a retardation plate for obtaining an elliptically polarizing plate by laminating with a polarizing plate include suitable polymers such as polycarbonate, polyvinyl alcohol, polystyrene, polymethyl methacrylate, polypropylene, other polyolefins, polyarylate and polyamide. A birefringent film obtained by stretching a film made of, a liquid crystal polymer having been subjected to an alignment treatment, and an alignment layer thereof supported by a transparent film substrate. The retardation plate may be one in which two or more kinds of retardation films or the like are laminated to control optical characteristics such as retardation.

The antiglare layer may be provided on one or both sides of the transparent film substrate, the polarizing plate, or the elliptically polarizing plate as described above, and one or more layers may be provided at appropriate positions on the display device. Can be applied in a state where an appropriate optical layer such as an anti-reflection layer is provided. The same applies to the case where an antiglare layer is provided on an appropriate member to form an optical member.

The anti-reflection layer is provided for the purpose of suppressing surface reflection of external light. For example, the anti-reflection layer may be formed of a multilayer coating film of an inorganic oxide having a different refractive index or a coating film of a low refractive material such as a fluorine compound. It can be formed on the anti-glare layer as an interference film or the like. Also, for example, when the anti-glare layer is used as an anti-reflection layer that reflects a fine uneven structure on the lower surface by an appropriate coating method such as a vapor deposition method such as a vacuum deposition method or an ion plating method, a sputtering method, a plating method or a sol-gel method, or the like. It can also serve as a combination.

Further, the antiglare layer and the optical member may be provided with a transparent conductive layer for the purpose of preventing static charge and shielding electromagnetic waves. As the transparent conductive layer, one layer or two or more layers can be provided at appropriate locations inside or on the surface of the layer forming the transparent film substrate or the optical member. The formation of the transparent conductive layer
For example, a coating method of a transparent conductive paint, a vacuum deposition method or a sputtering method of a conductive material, an ion plating method or a chemical vapor deposition method, a spray pyrolysis method or a chemical plating method,
It can be performed by an appropriate method such as an electroplating method or a method combining them.

The conductive materials include, for example, indium oxide and tin oxide, indium / tin mixed oxide and cadmium oxide, titanium oxide and indium, tin and gold, silver and platinum,
Appropriate materials such as palladium and copper, aluminum and nickel, chromium and titanium, iron and cobalt, copper iodide and their alloys can be used alone or in combination of two or more, and there is no particular limitation, and any of known materials is used. sell.

Further, on the surface of the anti-glare layer or the optical member, a fluorine-based surface treatment coat can be provided for the purpose of making it difficult for stains such as fingerprints to adhere and for facilitating the wiping of the adhered stains. In forming the coat, an appropriate fluorine-based compound that can form a film having a small surface energy, such as a fluorine-based resin or a fluorine-based silane coupling agent, can be used.

In addition, an adhesive layer may be provided on one or both surfaces of the antiglare sheet or the optical member, particularly on a surface having no antiglare layer, for the purpose of bonding to other members. For forming the pressure-sensitive adhesive layer, a pressure-sensitive adhesive having a base polymer of an appropriate polymer such as an acrylic polymer, a silicone-based polymer, polyester, polyurethane, polyether, or synthetic rubber can be used, and is not particularly limited. Among them, those having excellent optical transparency such as acrylic pressure-sensitive adhesives and exhibiting adhesive properties such as appropriate wettability, cohesiveness and adhesiveness are preferable, and those having excellent weather resistance and heat resistance in addition to the above are particularly preferable. preferable.

Incidentally, examples of the above-mentioned acrylic pressure-sensitive adhesive include an alkyl group having 20 or less carbon atoms such as a methyl group, an ethyl group, a butyl group, and an ethylhexyl group (meth).
Acrylic polymer using one or more alkyl ester of acrylic acid as a main component, and one of appropriate monomer components other than acrylic acid alkyl ester for the purpose of improving adhesive properties as required. Examples of the base polymer include those obtained by copolymerizing a kind or two or more kinds.

The attachment of the pressure-sensitive adhesive layer to the transparent film substrate, the optical member, or the like can be performed, for example, by directly applying the pressure-sensitive adhesive liquid on the transparent film substrate or the like by an appropriate developing method such as a casting method or a coating method. Alternatively, it can be performed by an appropriate method such as a method of forming an adhesive layer on a separator and transferring it onto a transparent film substrate or the like according to the above. The thickness of the adhesive layer can be appropriately determined according to the adhesive force and the like, and is generally 1 to 500 μm.
It is said.

If necessary, the adhesive layer may contain, for example, natural or synthetic resins, especially, tackifying resins, fillers, pigments, coloring agents, and antioxidants. Alternatively, a transparent particle may be blended to form an adhesive layer exhibiting light diffusion. Further, the adhesive layer can be provided as a superimposed layer of different compositions or types. When the adhesive layer is exposed on the surface, it is preferable to cover and protect the surface with a separator or the like until practical use.

In addition, an anti-glare layer and a transparent film substrate,
The optical member may have an ultraviolet absorbing ability by, for example, a method of treating the optical member with an ultraviolet absorbent such as a salicylic acid ester compound, a benzophenone compound, a benzotriazole compound, a cyanoacrylate compound, and a nickel complex compound. The antiglare layer and the optical member according to the present invention can be applied to various display devices such as a CRT, a plasma display, and a liquid crystal display device.

[0029]

Example 1 15 parts of transparent fine particles having an apparent density of 0.6 g / cm ³ and an average particle size of 2 μm were added to 100 parts (parts by weight, the same applies hereinafter) of an ultraviolet curable polyfunctional acrylic monomer, and a photopolymerization initiator 3 Part and an organic solvent were mixed and mixed with a homogenizer, and a dispersion having a solid content of 50% by weight was applied to one surface of a 50 μm-thick triacetylcellulose film with a bar coater, and cured by ultraviolet light through a high-pressure mercury lamp to obtain a thickness. An anti-glare sheet was obtained by forming an anti-glare layer of 9 μm.

When the cross section of the antiglare sheet was observed by SEM, the fine particles were unevenly distributed at the air-side interface, and the height of the fine particles was 1.2 μm and the diameter of the convex portions was 7 μm.
m, an average distance between the convex portions was 16 μm, and a fine surface uneven structure was formed. The anti-glare sheet has excellent scratch resistance of the anti-glare layer, and when the anti-glare layer is applied as a surface side to a color TFT liquid crystal display device with high definition image quality, no reduction in image clarity is observed. There was no glare and the antiglare effect was excellent.

Comparative Example 1 An antiglare layer was obtained by forming an antiglare layer in the same manner as in Example 1 except that the solid content of the dispersion was 30% and the thickness of the transparent resin layer was 3 μm. This anti-glare sheet is the same as in Example 1.
The surface fine irregularities conforming to the above were formed, and the sharpness of the image and the prevention of reflection of the outside scenery were good, but the scratch resistance of the antiglare layer was poor.

Comparative Example 2 An antiglare sheet was obtained by forming an antiglare layer according to Example 1 except that a transparent resin layer having a thickness of 10 μm was formed using transparent fine particles having an average particle size of 5 μm. This anti-glare sheet has a surface fine uneven structure in which the height of the unevenness is 3.5 μm, the diameter of the convex portion is 14 μm, and the average distance between the convex portions is 24 μm, and is excellent in abrasion resistance. , High definition image color T
When applied to an FT liquid crystal display device, the sharpness of an image is reduced,
The outside scene was reflected.

Comparative Example 3 An antiglare sheet was obtained by forming an antiglare layer in the same manner as in Example 1 except that the blending amount of the transparent fine particles was 5 parts and a 10 μm thick transparent resin layer was formed. This anti-glare sheet has a surface irregularity structure in which the height of the irregularities is 3.5 μm, the diameter of the projections is 14 μm, and the average distance between the projections is 24 μm.
Color TFT with excellent sharpness but high definition image quality
When applied to a liquid crystal display device, the sharpness of an image deteriorates, and the outside scene is reflected.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Takuya Matsunaga 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (72) Inventor Tomomori Masada 1-1-1, Shimohozumi, Ibaraki-shi, Osaka No. 2 Nitto Denko Corporation F term (reference) 2H042 AA09 AA26

Claims (3)

[Claims] 1. The height of unevenness based on a top and a valley is 0.5
１．５1.5 μm, and the size of the projection is 3 based on the diameter.
10 μm, and the average distance between the projections is 10 to 20
An antiglare layer comprising a transparent resin layer having a thickness of 8 μm or more and having a fine unevenness structure of μm on the surface. 2. The anti-glare layer according to claim 1, wherein the fine uneven structure on the surface is made of transparent fine particles. 3. An optical member comprising the antiglare layer according to claim 1 on at least one side of a transparent film substrate, a polarizing plate or an elliptically polarizing plate.