JPH01903A - Anti-glare filter - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a plastic anti-glare filter that has a high surface hardness and particularly excellent scratch resistance.

(Prior Art) Conventionally, in display devices such as CRTs, liquid crystal displays, and light emitting diodes, it has been difficult to see images due to glare caused by external light reflecting on the display screen and smudges caused by one reflection. There was a problem. Various anti-glare filters have been proposed to solve these problems, and many have been proposed.
An example is a multilayer structure in which thin films of materials with different refractive indexes are alternately provided on a base material. This kind of filter uses the interference effect of light and suppresses the reflection of light at a specific wavelength by specifying the refractive index and film thickness of the film material used.1 In normal environments, various Since there is light with a wide wavelength distribution, it is virtually impossible to eliminate reflections.

Furthermore, in order to lower the reflectance for many wavelengths, it is necessary to laminate many layers of thin films, which makes the process complicated. Furthermore, MgF2, which is used to prevent reflection in lenses, etc.
, LiF, 8102, ZrO2', 0e02
, Aj20B, etc., a method such as vapor deposition or sputtering must be used, resulting in poor productivity.

On the other hand, it has long been known that an anti-glare effect can be obtained by providing minute irregularities on the surface of the substrate, and an anti-glare filter that utilizes this effect can reduce the amount of glare caused by the image. Moreover, since it is relatively easy to manufacture, it is applied in various fields. however.

When a surface is provided with an uneven shape made of a commonly used base material itself such as polymethyl methacrylate or polycarbonate, there is a problem in that it is easily scratched due to a problem with the material itself.

Another method is to provide a resin coating in which fine silica particles are dispersed on the surface of the substrate, but in this case, in order to virtually eliminate the reflection of the reflected image, a large amount of silica particles must be included in the coating, so a uniform coating cannot be obtained. Dispersion is difficult, and the resulting filter has problems such as uneven coating on the surface.

(Problems to be Solved by the Invention) The present inventors have conducted various studies with the aim of obtaining an anti-glare filter that does not have one or more of the following drawbacks, and as a result, we have developed a method for forming a specific hardened coating on a transparent plastic substrate. The present inventors have discovered that by providing two layers, the surface hardness and scratch resistance can be significantly improved while maintaining the anti-glare effect.

(Rounding Means for Solving Problems) That is, according to the present invention, a transparent plastic substrate and a cured coating layer of an organic polysiloxane composition having a fine unevenness on one surface provided on at least a part of the surface thereof. (layer) and a coating layer (second layer) formed of a cured product of an organic polysiloxane composition or a cured product of a polyacrylate composition provided on the cured coating. A glare filter is provided.

Examples of transparent plastic substrates used in the present invention include polymethacrylate, polycarbonate, and
Examples include vinyl chloride, epoxy resin, polystyrene, polyester, diethylene glycol bisallyl carbonate resin, etc., but there is no particular limitation as long as it can transmit images without damaging the image on the display.

In addition to being used in the form of a plate or film, these plastic substrates can also be molded into any shape that matches the front shape of a cathode ray tube or the like.

As the coating material for the first layer on the surface of the substrate, cured products of various organopolysiloxane compositions can be used, but partial hydrolysates of trifunctional and/or tetrafunctional organosilicon compounds and their parts are also suitable. A condensate diluted with a suitable solvent is preferably used. Various materials for providing these cured products are already commercially available and can be easily prepared by hand. In addition, these materials contain an appropriate amount of 7-Li force fine particles.

Other additives may be added, which can improve scratch resistance, abrasion resistance, processability, and the like.

In order to form the film of the first layer on the base material, various conventional and commonly used coating methods can be applied, such as dipping method, spin method, roll method, flow method, etc. Can be mentioned. Further, if necessary, an adhesion improver can be provided between the base material and the second layer coating.

Methods for forming fine irregularities on the surface of the first layer coating include a method of roughening the surface using methods such as chemical etching or sandblasting, a method of forming irregularities using photolithography, or a method of forming irregularities on glass processed into an irregular shape. Methods such as transferring a pattern using a mold are used.

In terms of pattern uniformity and controllability, photolithography is preferred.

The surface roughness of the irregularities provided on the surface of the first layer liquid film can be set to various values depending on the required anti-glare property and in combination with the thickness of the second layer film, but in practice In order to produce a dazzling effect, it is desirable that the centerline average roughness (Ra) be at least 0.05 μm or more. Further, in order to prevent the occurrence of cracks, it is desirable that the thickness of the first layer coating is 20 μm or less as measured from the interface with the base material to the center of roughness.

As the coating material for the second layer, a cured product of an organic polysiloxane composition or a cured product of a polyacrylate composition having the same or different structure as the first layer coating is used. As with the cured product of the second layer, various materials can be used for the cured product of the organic polysiloxane composition. Various materials can be used as the polyacrylate composition, such as a (meth)acrylic prepolymer to which a photopolymerization initiator is added, or a mixture of a polyol (meth)acrylate monomer. or.

Similar to the second layer coating, fine silica particles or the like can be added to these materials to impart various properties. In addition,
In forming the second layer coating, the various coating methods described above can be applied.

The thickness of the second layer coating obtained is the same as that of the second layer coating.

In order to prevent cracks, the thickness is preferably 20 μm or less. In addition, the surface roughness after the formation of the second layer is 05 to 05 on the center line average roughness (Ra) in terms of anti-glare properties and light transmittance.
The thickness is preferably 10.0 μm.

This value can be freely adjusted by varying the roughness on the surface of the first layer coating and the thickness of the second layer coating.

In this way, the desired anti-glare filter is obtained, but if necessary, a hardening agent similar to that used in the second layer or the second layer in the present invention or another hardening agent may be applied on the back surface of the base material. A coating of material can be provided to impart scratch resistance.

Also for the purpose of eliminating flicker on one screen and improving contrast.

The base material or coating may be colored using pigments or dyes. Furthermore, inside or on the surface of the coating.

By incorporating or coating an antistatic agent inside or on the back side of the base material, it is possible to prevent dirt and dust from adhering to the base material.

(Effects of the Invention) According to the present invention, a transparent plastic anti-glare filter having high surface hardness and particularly excellent scratch resistance can be obtained.

(Example) Next, the present invention will be specifically explained using examples.

Comparative Example Adhesion improver (Toshiba Silicone PH95°) was placed on an acrylic resin plate (2m thick, Mitsubishi Rayon “Acrylite°”)
and Si-based hard coat agent (Toshiba Silicone 1 Toss Guard 520'') were spin-coated in this order and heated at 90C for 2 hours to form a cured film.The film thickness was 0.02 cm for each.
μm and 5.0 μm.

Next, a positive photoresist (Tokyo Ohka Kogyo = OFPR)
The film thickness is 1 μm on the cured film that was previously formed (-800”).
9. Spin coating so that it looks like this. Heat treatment was performed with OC for 20 minutes. After that, a mask with a grid-like black pattern of 140 mesh (wire diameter 60 μm) was pressed onto the resist, and the upper part of the mask was irradiated with 11 om:s7 (to) 2 ultraviolet rays using an ultra-high pressure mercury lamp, and developed with an alkaline aqueous solution. Form a resist pattern and further.

Heat treatment was performed at 90C for 20 minutes.

Using the obtained resist pattern as a mask, the cured film was etched at 2DC for 1 hour with 3 liters of fluoride/acid aqueous solution (containing ammonium fluoride), and then the resist was dissolved and removed with ethanol to form a cured film layer. A concavo-convex pattern was formed.

The obtained pattern is uniform, and the height difference is 3.6μ.
It was m. The 45° specular reflectance of this material is 5.5s (F), and the transmittance of light from 500 to 700 nm is 78
%Met. Moreover, the surface hardness was 4H in terms of pencil hardness.

However, when the surface was rubbed with $0,000 Steel Cool (steel wool test), the surface was slightly scratched.

Example 1 Using the sample plate obtained in the comparative example, a Si-based hard coating agent ("Tosgard 520") was spun onto the sample plate to a thickness of 1 μm, and heated at 90C for 2 hours.

The surface level difference of the obtained sample was 3.4 μm, the specular reflectance was 5.6%, and the transmittance was 78. The pencil hardness was 8H, and no scratches were observed in the steel wool test.

Example 2 Using the sample plate obtained in the comparative example, a photosensitive resin solution prepared according to the following formulation was spin-coated to a film thickness of 0.7 μm, and completely cured by ultraviolet irradiation. went.

Compounding of photosensitive resin solution Trimethylolpropane doryacrylate H]
3.5% Ingprol alcohol ya
o 1 The surface level difference of the obtained sample was 4.2 μm,
The specular reflectance was 4.9% and the transmittance was 74%. Furthermore, the pencil hardness was 7H, and there was no scratch in the reed or steel wool test.

Example 6 A sample was prepared in the same manner as in Example 1, except that 1mm Y-41-442'' (Toshi silicone, S1 hard coat agent) was used as the second layer film forming material.

The thickness of the second layer cured film was 1.2 μm.

The surface level difference of the obtained sample was 3.1 μm, the specular reflectance was 6.0%, and the transmittance was 81%. The pencil hardness of this product was 8H, and it did not show any scratches in the steel wool test.

Patent applicant: Zeon Corporation

Claims (1)

[Claims] A transparent plastic base material, a cured coating layer of an organic polysiloxane composition having a finely uneven shape on the surface provided on at least a portion of the surface thereof, and curing of the organic polysiloxane composition provided on the cured coating. 1. An anti-glare filter comprising a coating layer made of a cured product of polyacrylate or a polyacrylate composition.