JPH0784103A - Diffusion plate and its production - 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 diffuser plate for use in video equipment such as a projection television receiver.

[0002]

2. Description of the Related Art Conventionally, as diffuser plates (including those for filters, the same applies hereinafter) used in various video equipment, silica whose size and shape are not uniform in the base material forming the plate, A diffuser plate in which a diffuser such as quartz or calcium carbonate is randomly mixed, or a diffuser plate processed by a chemical treatment method, a pressing method, a sand breast method, etc. so that one side or both sides of the plate have an uneven shape is generally used. Has been used for.

However, the former one containing the diffusing material is
Since the thickness of the diffusing plate is usually 2 mm or more, the diffusing materials are often present in the plate in a state of being multiplexed with each other. However, there is a problem in that it causes stray light and reduces the light transmittance. On the other hand, also in the case of the latter surface-treated diffuser plate, since finer unevenness is formed on the surface-processed uneven shape, incident light is reflected in these large and small unevenness in a complicated manner to generate stray light, There is a problem in that a loss of transmitted light occurs and the transmittance also decreases.

Further, in any of the conventional diffusion plates described above, external light is diffusely reflected by the diffusion material protruding on the surface and fine irregularities on the surface, and the surface of the diffusion plate looks whitish, which makes it difficult to see the screen. there were. In addition, since the material of the diffuser plate is resin, the surface resistance value is as large as 10 ^{15 to 18} Ω, and there is a problem that dust and dirt in the air adhere to the surface due to a charging phenomenon due to static electricity.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves various problems of the above-mentioned conventional diffuser plate, improves the light transmittance, prevents diffused reflection of external light, and prevents surface reflection. An object of the present invention is to provide an excellent diffuser plate which has a bright and clear feeling by eliminating the attachment of dust, dust and the like, and has less reflection, by preventing the electrification.

[0006]

In order to solve the above-mentioned problems, the inventors of the present invention have conducted extensive studies on a diffusing material, an antistatic agent, a method of supporting the diffusing material, an antistatic agent, and a structure of a diffusing plate in which they are laminated. As a result, the diffusing material is formed into spherical fine particles having a constant spherical diameter, and the fine particles are printed by a printing method so as to be arranged side by side in a constant thickness.
The present invention has been completed by finding that a diffusing plate having a desired effect can be obtained by using O ₂ powder, applying it by a printing method, and using the diffusing surface with the incident light side.

That is, according to the present invention, a transparent or semi-transparent resin substrate and a particle size of 1 to 50 provided on the plane on the light incident side thereof.
A diffusing layer formed by printing a printing ink containing a diffusing material composed of micron spherical light diffusing fine particles to a thickness of 10 to 20 microns thicker than the maximum particle size of the diffusing material, and a plane on the light emitting side of the resin substrate. A diffusion plate comprising an antistatic layer formed by printing a printing ink containing a particulate antistatic agent having a particle size of 0.5 micron or less, and a method for producing the same.
And its use.

The present invention will be described in detail below. 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 semitransparent resin substrate 1, and an antistatic layer 5 on the opposite side, that is, a light emission side surface. It has a laminated structure. If the arrangement of the diffusion layer and the antistatic layer is not set as described above, part of the emitted light, that is, light with a large incident angle, is totally reflected due to the unevenness of the surface of the diffusion layer, and the amount of transmitted light and haze decrease. Not preferable.

The resin substrate 1 is a colorless or colored transparent plate or semi-transparent plate having a plate thickness of 1 to 5 mm, and as its material, acrylic resin, polycarbonate resin, styrene resin, etc. are used. Then, acrylic resin is preferable. Dark-smoked tones are often used as the colored semi-transparent plate. Incidentally, it generally takes time 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 constituent element. The diffusing layer 2 is uniformly formed on the surface of the resin substrate 1 using an ink prepared by dispersing and mixing the diffusing material 3 in a plastic printing ink 4 and the diffusing material 4 is formed as shown in FIG.
It is formed by printing so as to be juxtaposed substantially in a horizontal row as shown in FIG. As described above, the diffusing materials are arranged in a horizontal row in the diffusing layer, and are arranged side by side in a single layer.Therefore, incident light is stray light due to undesired reflection that occurs in the conventional case where the diffusing material is multiplexed. Since no loss of transmitted light occurs, good light transmittance can be obtained.

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

Since this diffusing material has a great influence on the uniformity of the diffusing layer, it is necessary to use the following specific shape and size. First, a spherical shape is used, the average particle size is 1 to 50 microns, and the range of variation is preferably 5 ± 4 microns.
It is selected from the range of 25 ± 25 microns. That is, the variation range of the particle size is 30 microns or less, preferably 2
It is necessary to keep it below 5 microns.

When this diffusing material is used, for example, when the thickness of the diffusing layer is about 15 microns, spherical fine particles (resin beads) having an average particle size of 15 microns or less with a variation of 1 to 10 microns. It is better to use
If the thickness of the diffusion layer is about 50 microns, 25
It is preferable to have an average particle size selected from the range of 25 to 50 microns, which has a variation within micron.

As the printing ink 4 for dispersing and mixing the diffusing material described above, a printing ink for plastics having an acrylic resin, polyester resin, urethane resin or the like as a binder is used. Among these, acrylic printing ink is particularly preferable. Further, it is preferable to add a light absorbing substance such as a dye, a pigment, carbon or a metal salt to the ink for coloring.

When the diffuser plate is used as a front panel of a video device, a resin substrate mixed with a light absorbing substance is used in order to prevent a decrease in contrast to external light due to reflection of external light. It was impossible to cope with diversification because the number of manufacturing steps increased, the cost increased, and the selection range was narrowed, but it was possible to control the light absorption rate by using the method for coloring the printing ink of the present invention. There is an advantage that it becomes easy, and light absorption, color tone and the like can be freely manufactured economically according to demand. Of course, both the resin substrate and the printing ink may be colored before use.

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

In the diffusion plate of the present invention, the antistatic layer 5 is provided on the surface of the resin substrate opposite to the diffusion layer surface. The antistatic layer is formed by the ink 7 in which the antistatic agent 6 is mixed and dispersed.
Is uniformly printed. Without the antistatic layer, the surface resistance value is 10 because the diffusion plate is made of resin.
It becomes ^16-18 Ω, and static electricity is generated due to friction and electric discharge, and dust and dirt adhere to it. As a result, there are problems that the image is difficult to see and the appearance of the screen is impaired.
In the present application, since the antistatic layer can be formed by using a suitable antistatic agent for the diffusion plate and the surface resistance value can be set to 10 ¹¹ Ω or less, the above static electricity problem does not occur.

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

Next, a method for manufacturing the diffusion plate of the present invention will be described. The resin substrate is formed by extruding or casting the above resin into a sheet or plate having a thickness of 1 to 5 mm, and it is convenient to use a commercially available product which meets the standards of the present invention. These substrates are thoroughly washed with ultrasonic waves before printing. Further, the diffusing material-containing printing ink and the antistatic agent-containing printing ink are added to the above-mentioned diffusing material and antistatic agent in the plastic printing ink, and well dispersed and mixed to prepare. 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, it is preferable to mix a coloring material such as a light absorbing substance with these printing inks.

First, a printing ink containing an antistatic agent 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 this, a printing material containing a 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.

Further, as described above, it is important to select the grain size of the diffusing material in accordance with the intended thickness of the diffusing layer and keep the variation of the grain size of the diffusing material within a certain range (maximum 30 μm). is there. By carrying out screen printing while suppressing these points, it is possible to obtain a target uniform diffusion layer in which spherical diffusion particles are arranged in a line in a row. After printing the diffusion layer, the desired diffusion plate is obtained by sufficiently drying it by a conventional method.

The above-described method for manufacturing a diffusion plate of the present invention is an extremely simple and economical method called a screen printing method by devising a diffusing material, an antistatic agent, and a printing ink. It is possible to say that this is a manufacturing method having a large industrial effect.

[0023]

The diffusing layer of the diffusing plate of the present invention has a structure in which spherical fine particle diffusing materials (resin beads) having a constant particle diameter are arranged in a row in a row, so that the conventional diffusing materials are randomly arranged. Compared with the diffuser plate embedded by overlapping with, the incident light rays were reflected by the multiple diffusing materials and were not lost as stray light, and the light transmittance was improved.

Further, by arranging the diffusing layer on the light incident side, it is possible to prevent the reflection due to the unevenness of the screen surface (which is also greatly reduced as compared with the conventional one) and the irregular reflection of external light. It was Further, since the antistatic layer of the diffusion plate of the present invention uses SnO _{2 of} 0.5 micron or less, a transparent film obtained when fine particles of 1 micron or less are dispersed is obtained, so that the light transmittance of the entire layer is obtained. Was improved, and the light transmittance of this layer itself could be increased. It is presumed that the diffusion plate of the present invention exerts the above-mentioned advantageous effects, which are unprecedented, by integrating the above-mentioned effects.

[0025]

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

Example 1 SnO ₂ having a particle size of 0.1 to 0.5 micron was formed on one surface of a transparent acrylic plate [Delaglass A (trade name) manufactured by Asahi Kasei Kogyo].
[Antistatic agent, Catalyst Chemical Industry Co., Ltd., ELCOM P
3561 (trade name)] was uniformly dispersed in a transparent acrylic printing ink and printed by screen printing with a 350 mesh plate. After drying this at 80 ° C. for 10 minutes, the surface resistance value was measured by a conventional method. As a result, the surface resistance value 10 ¹⁶ Ω of the acrylic plate before printing was lowered to 10 ⁸ Ω.

Next, a viscosity-adjusted printing ink containing a diffusing material having the following composition was applied to the back surface of the transparent acrylic plate on which the band-preventing layer was present, and then printed by screen printing with a 350 mesh plate to form a diffusing layer. . (Compounding) Diffusion material: Acrylic resin beads manufactured by Sekisui Plastics Co., Ltd. (Brand name: Technopolymer MBX) 5 micron 20% by weight Colorant: Black acrylic ink (# 690) manufactured by Jujo Chemicals Co., Ltd. 10 wt% Base ink: transparent acrylic ink (medium ink) manufactured by Jujo Chemicals Co., Ltd. 70 wt%

After printing, the product was dried at 80 ° C. for 20 minutes to obtain a target diffusion plate. This diffuser plate is arranged so that the diffuser layer 2 is in contact with the black stripe 10 side of the screen including the Fresnel lens 8 and the lenticular lens 9 shown in FIG. 2, that is, the emitted light 12 side closest to the observer. And the screen was manufactured. When this screen was attached to a projection television and used, as compared with the conventional screen in which a diffusing material was mixed in the lenticular lens, stray light due to reflection was eliminated, and as a result, color shift, reduction in resolution and viewing angle We were able to solve the problems of narrowing all at once. Further, by printing the colored ink containing the diffusing material, an image with excellent contrast was obtained without irregular reflection due to external light.

Example 2 A dark smoked semi-transparent acrylic plate [Delagrass A923 (trade name) manufactured by Asahi Kasei Kogyo KK] was used in Example 1.
The SnO ₂ -containing ink used in Example 1 was depped and then dried to form an antistatic layer on both sides. The surface resistance value was 10 ⁸ Ω.

Next, a diffusing material-containing printing ink having the following composition prepared so that the light transmittances of the ink and the diffusing material were substantially the same was printed on one surface of the ink by screen printing with a 350 mesh plate to form a diffusing layer. . (Compounding) Diffusion material: Sekisui Plastics Co., Ltd. acrylic resin beads 5 micron (Product name: Technopolymer MBX) 20% by weight Coloring agent: Jujo Kako Co., Ltd. black acrylic ink (# 690) ... 5% by weight Base ink: transparent acrylic ink (medium ink) manufactured by Jujo Chemicals 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 screen of a projection television 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 calm color tone and a texture. It looked even more.

Example 3 A diffusing plate was manufactured in the same manner as in Example 1 except that the ink containing the diffusing material was changed to the following composition, and was used in the screen of the projection television in the same manner as in Example 1. However, the same effect as in Example 1 was obtained. (Compounding) Diffusing material: Black colored acrylic resin beads 5 micron 20% by weight (Production method: 50 ppm of a black colorant (Sumitaplast G2, Sumitomo Chemical Co., Ltd.) was mixed with methyl methacrylate, followed by suspension polymerization. 5 micron spherical fine particle beads were obtained) Colorant: Black acrylic ink (# 690) manufactured by Jujo Chemicals Co., Ltd. 5% by weight Base ink: Transparent acrylic ink (medium ink) manufactured by Jujo Chemicals Co., Ltd. 75% by weight

[0033]

INDUSTRIAL APPLICABILITY The diffusion plate of the present invention is extremely useful as a front panel of a video equipment such as a projection type television receiver, and when used for them, it has an original performance of shielding a light source and other internal structures. While exhibiting sufficiently, it has an excellent effect that the resolution and the viewing angle are improved, the contrast to external light is good, and dust and dust are not attached due to static electricity.
In addition, since the manufacturing method is a screen printing method, which is an extremely simple and economical method that does not require replacement of molds or the like,
It is easy to meet various demands, can be made thin, and can be manufactured at low cost.

[Brief description of drawings]

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

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 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 Incoming light 12 Outgoing light

Claims (8)

[Claims] 1. A printing ink containing a transparent or semi-transparent resin substrate and a diffusing material composed of spherical light diffusing fine particles having a particle size of 1 to 50 μm provided on a plane on the light incident side of the resin is the maximum of the diffusing material. Printing a printing ink containing a diffusion layer formed by printing 10 to 20 μm thicker than the particle size and a fine particle antistatic agent having a particle size of 0.5 μm or less provided on the light emitting side plane of the resin substrate. A diffusion plate comprising an antistatic layer formed by the above. 2. The diffusing material is made of a resin having an optical refractive index similar to that of the resin substrate and has an average particle diameter of 5 ± 4 μm to 25 μm.
The diffuser plate according to claim 1, which is spherical light diffusing resin beads in a variation range of ± 25 microns, and wherein the diffusing materials are arranged substantially in a row in the diffusing layer. 3. The diffusion plate according to claim 1, wherein the antistatic agent is tin oxide having a particle size of 0.5 μm or less. 4. The diffusion plate according to claim 1, wherein at least one of the resin substrate, the diffusion material, and the printing ink is colored. 5. An antistatic agent-containing printing ink prepared by mixing and dispersing an antistatic agent made of tin oxide having a particle size of 0.5 μm or less in advance on a plane on the light emitting side of a transparent or semitransparent resin substrate. To form an antistatic layer, and then a particle size of 1 is preliminarily formed on the light incident side plane of the resin substrate.
Characterized in that a diffusing material-containing printing ink prepared by mixing and dispersing a spherical light diffusing diffusing material having a particle size of up to 50 microns is printed with a screen printing plate having a mesh suitable for the particle size of the diffusing material to form a diffusing layer. Method for manufacturing diffuser plate. 6. When forming the diffusion layer, the diffusion materials in the diffusion layer are arranged substantially in a row in a row, and the thickness of the diffusion layer is 10 to 20 μm thicker than the maximum particle diameter of the diffusion material used. The method for producing a diffusion plate according to claim 5, wherein the diffusing material-containing printing ink is printed using a screen printing plate having an appropriate mesh. 7. The method for producing a diffusion plate according to claim 5, wherein, when the printing ink containing the diffusing material is prepared, the ink is colored with a coloring agent or a coloring ink. 8. A screen for a projection type television receiver using the diffusion plate according to claim 1.