JP3265755B2 - Diffusion plate and method of manufacturing the same - Google Patents

Abstract

PURPOSE:To improve light contrast to external light and to Prevent the sticking of dust and dirt by static electricity by consisting the diffusion plate of an antistatic layer which is provided on the plane on a light exit side and is formed by printing with printing ink contg. a fine granular antistatic agent having a grain size of a specific value or below. CONSTITUTION:This diffusion plate has a diffusion layer 2 formed by printing with the printing ink 4 contg. a diffusing material consisting of spherical light diffusive particulates having the grain sizes of 1 to 50mum on the light incident side surface of a transparent or translucent resin substrate 1 at a thickness larger by 10 to 20mum than the max. grain size of the diffusing material 3. The diffusing material 3 has a significant influence on the uniformity of the diffusion layer 2 and its shape is spherical. The average grain size thereof is selected from a range of 1 to 50mum. Tin oxide (SnO2) having the most preferable grain size of <=0.5mum is used as the antistatic agent 6. This SnO2, is dispersed and mixed into the plastic printing ink 7 and the surface of the resin substrate 1 on the side opposite to the diffusion layer 2 is uniformly printed with this ink. The transparent antistatic layer 5 decreased in the surface resistance value to <=10<11>OMEGA is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an excellent diffusion plate used for video equipment such as a projection type television receiver.

[0002]

2. Description of the Related Art Conventionally, as a diffusion plate (including a filter application, the same applies hereinafter) used in various video equipment, silica, which is not uniform in size and shape in a base material forming the plate, is used. Generally, a diffusion plate in which a diffusion material such as quartz or calcium carbonate is randomly mixed, or a diffusion plate processed by a chemical treatment method, a press method, a sand-breast method, or the like so that one or both surfaces of the plate have an uneven shape. Has been used for

[0003] However, when the former diffusing material is mixed,
Due to the fact that the thickness of the diffusion plate is usually 2 mm or more, the diffusion material is often multiplexed with each other in the plate, so that the passing light beam hits the diffusion material several times and a part of the light is reflected. Then, there is a problem that stray light is caused and light transmittance is reduced. On the other hand, in the case of the latter surface-diffusion plate, since finer irregularities are formed on the surface-irregularities, the incident light is reflected in these large and small irregularities in a complicated manner, resulting in stray light. There is a problem that a loss of transmitted light occurs and the transmittance also decreases.

In addition, the above-mentioned conventional diffusion plate has a problem that external light is irregularly reflected by a diffusion material protruding from the surface or fine irregularities on the surface, so that the surface of the diffusion plate looks whitish and the screen becomes difficult to see. there were. In addition, since the material of the diffusion plate is a resin, the surface resistance is as large as 10 ^{15 to 18} Ω, and there is a problem that dust and dust in the air adhere to the surface due to a charging phenomenon due to static electricity.

[0005]

SUMMARY OF THE INVENTION The present invention solves the various problems of the above-mentioned conventional diffuser plate, improves the light transmittance, prevents irregular reflection of external light, and improves the surface roughness. An object of the present invention is to provide an unprecedented excellent diffuser plate which has an antistatic property, is free of dust and dirt, has a bright and clear feeling, and has less reflection.

[0006]

Means for Solving the Problems In order to solve the above problems, the present inventors have intensively studied a diffusing material, an antistatic agent, a method for supporting the same, and a structure of a diffusing plate in which they are laminated. As a result, the diffusing material was formed into spherical fine particles having a constant spherical diameter, and the particles were printed by a printing method so as to be arranged side by side in a row at a constant thickness.
It has been found that a diffusion plate having an intended effect can be obtained by using O ₂ powder, applying the coating by a printing method, and using the diffusion surface on the side of incident light, thereby completing the present invention.

Accordingly, the present invention provides a transparent or translucent resin substrate, provided on the plane of the light incident side, and a resin substrate
A resin having a similar light refractive index is used as a material, and the average particle diameter is 5
± 4 microns to 25 ± 25 microns
A printing ink containing a diffusing material comprising spherical light diffusing resin beads is printed 10 to 20 microns thicker than the maximum particle size of the diffusing material, and the diffusing material is substantially dispersed in the diffusion layer.
A charging layer formed by printing a diffusion layer arranged in a horizontal line and a printing ink containing a fine antistatic agent having a particle diameter of 0.5 μm or less provided on a plane on the light emitting side of the resin substrate. An object of the present invention is to provide a diffusion plate comprising an prevention layer, a method for producing the same, and uses thereof.

Hereinafter, the present invention will be described in detail. As shown in FIG. 1, the diffusion plate of the present invention has a diffusion layer 2 laminated on a light incident side surface of a transparent or translucent resin substrate 1, and an antistatic layer 5 on the opposite side, that is, a light exit side surface. It has a laminated structure. If the arrangement of the diffusion layer and the antistatic layer is not made as described above, part of the emitted light, that is, light having a large incident angle is totally reflected due to unevenness of the surface of the diffusion layer, so that the amount of transmitted light and the haze decrease. Not preferred.

The resin substrate 1 is a colorless or colored transparent or translucent plate having a thickness of 1 to 5 mm, and an acrylic resin, a polycarbonate resin, a styrene resin or the like is used as the material. In this case, an acrylic resin is preferable. Further, as a colored translucent plate, a dark-smoke-like one is often used. In addition, it generally takes time and effort to produce a good colored translucent plate suitable for the present invention,
Since the cost is high, it is more preferable to color the diffusion layer by using a coloring ink containing a diffusion material as described later.

In the present invention, the diffusion layer 2 can be said to be the most important component. The diffusion layer 2 is formed on the surface of the resin substrate 1 by using an ink prepared by dispersing and mixing a diffusion material 3 in a plastic printing ink 4 and the diffusion material 4 is formed as shown in FIG.
As shown in FIG. 2, the printing is performed so as to be arranged substantially in a horizontal line. As described above, the diffusing materials are arranged in a horizontal line in the diffusing layer, and are arranged side by side in a single layer. Since no loss occurs in transmitted light, good light transmittance is obtained.

The diffusing material 3 used in the present invention is a fine spherical sphere having a sharp particle size distribution such as an acrylic resin such as a methyl methacrylate resin or a copolymer thereof, a styrene resin, a polyester resin, a polycarbonate resin, and a fluorine resin. Resin beads are used. Although transparent resin beads are used, they may be colored. Also, inorganic beads such as glass beads can be used.

Since this diffusion material greatly affects the uniformity of the diffusion layer, it is necessary to use the following specific shapes and sizes. First, a spherical shape is used, the average particle size of which is 1 to 50 microns, and the range of the variation is preferably 5 ± 4 microns.
It is selected from the range of 25 ± 25 microns. That is, the range of the variation of the particle size is 30 μm or less, preferably 2 μm or less.
It must be kept below 5 microns.

When this diffusion material is used, for example, when the thickness of the diffusion layer is about 15 μm, spherical fine particles (resin beads) having an average diameter of 15 μm or less and having a variation of 1 μm to 10 μm. It is better to use
When the thickness of the diffusion layer is about 50 microns, 25
The average particle diameter is preferably selected from the range of 25 to 50 microns having a variation within the microns.

As the printing ink 4 for dispersing and mixing the above-described diffusing material, a printing ink for plastics using an acrylic resin, a polyester resin, a urethane resin or the like as a binder is used. Of these, acrylic printing inks are particularly preferred. It is also preferable to color the ink by adding a light-absorbing substance such as a dye, a pigment, carbon, or a metal salt in the ink.

When a diffusion plate is used as a front panel of a video device, a resin substrate mixed with a light-absorbing substance is used to prevent a decrease in external light contrast due to reflection of external light. Although the manufacturing process is increased, the cost is increased, and the selection range is narrowed, and the diversification cannot be performed. There is an advantage that it can be easily manufactured, and light absorption, color tone, and the like can be freely and economically manufactured as required. Of course, both the resin substrate and the printing ink can be colored and used.

The printing ink containing a diffusing material described above must be printed uniformly on a resin substrate so that the diffusing material forms a horizontal line. In order to obtain such a diffusion layer, a printing method, particularly preferably a screen printing method is used. In the screen printing method, by making the mesh suitable for the particle size of the diffusion material, the diffusion material can be regularly arranged in a single layer by the screen mesh, and a uniform diffusion layer can be formed.

In the diffusion plate of the present invention, an antistatic layer 5 is provided on the surface of the resin substrate opposite to the surface of the diffusion layer. This antistatic layer is composed of ink 7 in which antistatic agent 6 is mixed and dispersed.
Is formed by printing uniformly. Without the antistatic layer, since the diffusion plate is made of resin, the surface resistance value is 10
^The resistance becomes ^{16 to 18} Ω, and static electricity is generated due to friction, discharge, and the like, and dust and dirt adhere to the image.
In the present application, since the antistatic layer is formed by using a suitable antistatic agent for the diffusion plate, and the surface resistance can be reduced to 10 ¹¹ Ω or less, the above-mentioned static electricity problem does not occur.

As the antistatic agent used in the present invention, any one of known antistatic agents can be appropriately selected and used, but most preferably, tin oxide (SnO ₂ ) having a particle size of 0.5 μm or less is used. It is. The SnO ₂ is dispersed and mixed in a plastic printing ink, for example, an acrylic printing ink, and is uniformly printed on the surface of the resin substrate opposite to the diffusion layer by a printing method, for example, screen printing. Thus, the transparent antistatic layer of the present invention having a surface resistance of 10 ¹¹ Ω or less is formed.

Next, a method for manufacturing a diffusion plate of the present invention will be described. As the resin substrate, a resin or a sheet obtained by molding the above-mentioned resin into a sheet or plate having a thickness of 1 to 5 mm by extrusion or casting is used, and it is convenient to use a commercially available product meeting the standards of the present invention. These substrates are thoroughly cleaned by ultrasonic waves or the like before printing. In addition, the printing material containing the diffusing material and the printing ink containing the antistatic agent are added to the above-mentioned diffusing material and the antistatic agent in the plastic printing ink, and well dispersed and mixed to prepare. Note that a method that destroys the shape of the diffusing material, such as a ball mixer or a roll mixer, should not be used for the dispersion mixing. As described above, a colorant such as a light absorbing substance is preferably mixed with these printing inks.

First, an antistatic agent-containing printing ink is printed on a resin substrate by a printing method such as a screen printing method or is dipped to form an antistatic layer. Next, after drying it, the printing ink containing the diffusing material is printed on the other surface of the resin substrate by screen printing. For this printing, it is important to print using a mesh screen suitable for the particle size of the diffusing material.

As described above, it is also important to select the particle size of the diffusion material according to the thickness of the target diffusion layer, and to keep the dispersion of the particle size of the diffusion material within a certain range (30 μm at the maximum). is there. If screen printing is performed with these points suppressed, it is possible to obtain a uniform diffusion layer in which spherical diffusion fine particles are arranged side by side in a desired row. After printing the diffusion layer, it is sufficiently dried by an ordinary method to obtain a target diffusion plate.

The method of manufacturing a diffusion plate according to the present invention described above is an extremely simple and economical method called screen printing by devising a diffusion material, an antistatic agent, and a printing ink. It can be said to be a production method having a large industrial effect.

[0023]

The diffusion layer of the diffusion plate of the present invention has a structure in which spherical fine particle diffusing materials (resin beads) having a certain particle size are arranged in a horizontal line, so that the conventional diffusing materials are randomly arranged with respect to each other. As compared with the diffuser plate embedded and superimposed, the incident light was not reflected by the multiplexed diffusing material and turned into stray light to be lost, and the light transmittance was improved.

Further, by arranging the diffusion layer on the light incident side, it is possible to prevent the reflection due to the unevenness of the screen surface (which itself is greatly reduced as compared with the conventional one) and the irregular reflection of external light. Was. Further, since the antistatic layer of the diffusion plate of the present invention uses SnO _{2 of} 0.5 μm or less, a transparent film can be obtained when fine particles of 1 μm or less are dispersed, so that the light transmittance of the entire layer is obtained. And the light transmittance of this layer itself could be increased. It is presumed that the diffusing plate of the present invention exerts the above-mentioned effects and effects and exhibits excellent performance which has never been achieved before.

[0025]

The present invention will be specifically described below with reference to examples.

Example 1 A transparent acrylic plate [Deraglass A (trade name) manufactured by Asahi Kasei Kogyo] was coated on one surface with SnO ₂ having a particle size of 0.1 to 0.5 μm.
[Antistatic agent, manufactured by Catalyst Chemicals, Inc., ELCOM P
3561 (trade name)] was uniformly dispersed in a transparent acrylic printing ink and printed by screen printing on a 350 mesh plate. After this was dried for 10 minutes at 80 ° C., where the surface resistance value was measured by a conventional method, a surface resistance of 10 ¹⁶ Omega of the acrylic plate before printing was reduced to 10 ⁸ Omega.

Next, on the back surface of the transparent acrylic plate on which the band-preventing layer is located, a printing ink containing a diffusion material having the following composition was adjusted in viscosity and then printed by screen printing on a 350 mesh plate to form a diffusion layer. . (Blend) Diffusion material: Acrylic resin beads manufactured by Sekisui Plastics Co., Ltd. (trade name: Techno Polymer MBX) 5 microns 20% by weight Colorant: Black acrylic ink (# 690) manufactured by Jujo Chemical Co., Ltd. 10% by weight Base ink: Transparent acrylic ink (medium ink) manufactured by Jujo Kako Co., Ltd. 70% by weight

After printing, drying was performed at 80 ° C. for 20 minutes to obtain a target diffusion plate. The diffusing plate is arranged such that the diffusing layer 2 is in contact with the side of the black stripe 10 of the screen composed of the Fresnel lens 8 and the lenticular lens 9 shown in FIG. And a screen was manufactured. When this screen was mounted on a projection television and used, the stray light due to reflection was reduced compared to a conventional screen in which a diffusing material was mixed in a lenticular lens, and as a result, color shift and resolution were reduced, and the viewing angle was reduced. The problem of narrowing was also solved at once. Further, by printing the colored ink containing the diffusing material, an image having excellent contrast was obtained without irregular reflection due to external light.

Example 2 A translucent acrylic plate of a dark smoke tone [Delaglass A923 (trade name) manufactured by Asahi Kasei Corporation) was used in Example 1.
The ink was dipped in the SnO ₂ -containing ink used in the above, and then dried to form an antistatic layer on both sides. Its surface resistance was 10 ⁸ Ω.

Next, a diffusion material-containing printing ink having the following composition prepared so that the light transmittance of the ink and the diffusion material was substantially the same was printed on one surface thereof by screen printing on a 350 mesh plate to form a diffusion layer. . (Blend) Diffusion material: Acrylic resin beads 5 micron manufactured by Sekisui Plastics Co., Ltd. (trade name: Techno Polymer MBX) 20% by weight Colorant: Black acrylic ink (# 690) manufactured by Jujo Chemical Co., Ltd. … 5% by weight Base ink: Transparent acrylic ink (medium ink) manufactured by Jujo Kako Co., Ltd.… 75% by weight

After printing, a diffusion plate was obtained by drying at 80 ° C. for 20 minutes. When this diffusion plate was used for a projection type television screen in the same manner as in Example 1, the same effect as in Example 1 was obtained, and the front screen after turning off the power had a subdued color tone and texture. It looked even more.

Example 3 A diffusing plate was produced in the same manner as in Example 1 except that the ink containing the diffusing material had the following composition, and used for a screen of a projection television in the same manner as in Example 1. However, the same effect as in Example 1 was obtained. (Compound) Diffusion material: Acrylic resin beads colored black 5 microns 20 wt% (Production method: 50 ppm of a black colorant (Sumiplast G2, Sumitomo Chemical Co., Ltd.) is mixed with methyl methacrylate, followed by suspension polymerization. 5 micron spherical fine-particle beads were obtained.) Colorant: black acrylic ink (# 690) manufactured by Jujo Kako Co., Ltd. 5% by weight Base ink: transparent acrylic ink (medium ink) manufactured by Jujo Kako Co., Ltd. 75% by weight

[0033]

The diffuser plate of the present invention is extremely useful as a front panel for video equipment such as a projection type television receiver, and when used in such a diffuser, has the original performance of shielding a light source and other internal structures. While exerting sufficient effects, the resolution and the viewing angle are improved, the external light contrast is good, and there is an excellent effect that dust and dust are not attached due to static electricity.
In addition, since the manufacturing method uses a very simple and economical method that does not require replacement of a mold or the like called a screen printing method,
There is an effect that it is easy to respond to various requests, can be thinned, and can be manufactured at low cost.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a diffusion plate of the present invention.

FIG. 2 is a partially cutaway perspective view showing one embodiment of a projection type television screen using the diffusion plate of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 resin substrate 2 diffusion layer 3 diffusion material 4 printing ink (for diffusion layer) 5 antistatic layer 6 antistatic agent 7 printing ink (for antistatic layer) 8 Fresnel lens 9 lenticular lens 10 black stripe 11 incident light 12 outgoing light

Claims (7)

(57) [Claims] 1. A transparent or translucent resin substrate and a light refractive index similar to that of the resin substrate provided on a plane on the light incident side thereof.
Having a mean particle size of 5 ± 4 microns to 2
Spherical light-diffusing trees in the range of 5 ± 25 microns
A printing ink containing a diffusing material composed of fat beads is printed 10 to 20 microns thicker than the maximum particle size of the diffusing material , and
Spreading materials are arranged substantially in a horizontal line in the diffusion layer.
And an antistatic layer formed by printing a printing ink containing a fine antistatic agent having a particle size of 0.5 μm or less provided on a plane on the light emission side of the resin substrate. Diffuser. 2. The diffusion plate according to claim 1, wherein the antistatic agent is tin oxide having a particle size of 0.5 μm or less. 3. The diffusion plate according to claim 1, wherein at least one of the resin substrate, the diffusion material, and the printing ink is colored. 4. A printing ink containing an antistatic agent prepared by mixing and dispersing an antistatic agent composed of tin oxide having a particle diameter of 0.5 μm or less in advance on a plane on the light emitting side of a transparent or translucent resin substrate. To form an antistatic layer, and then a particle size of 1
A diffusion material-containing printing ink prepared by mixing and dispersing a spherical light-diffusing diffusion material of about 50 microns with a screen printing plate having a mesh suitable for the particle size of the diffusion material to form a diffusion layer. Manufacturing method of the diffusion plate. 5. In forming the diffusion layer, the diffusion materials in the diffusion layer are arranged substantially in a horizontal line, and the thickness of the diffusion layer is 10 to 20 μm thicker than the maximum particle size of the diffusion material used. 5. The method according to claim 4, wherein the printing ink containing the diffusion material is printed using a screen printing plate having an appropriate mesh. 6. The method for producing a diffusion plate according to claim 4 , wherein, when preparing the printing ink containing the diffusion material, the ink is colored with a coloring agent or a coloring ink. 7. A projection type television receiver screen using the diffusion plate according to claim 1.