JPS59143618A - Manufacture of transmitting type screen - Google Patents

Abstract

PURPOSE:To improve resolving-power and a contrast of a screen, and peculiarity of diffusion and distribution of light, by a method wherein a thin diffusion- filmlike subject is manufactured by stretching a synthetic resin sheet mixed evenly with a light diffusion agent, which is laminated together with a transparent resin sheet by pressure heating. CONSTITUTION:A diffusion-filmlike subject is adhered unitarily on the upper surface of a transparent resin sheet 1 by pressure heating. A metacrylic resin plate, a polyvinyl chrolide resin plate, a polycarbonate plate are desirable for the transparent resin sheet and silicon oxide, aluminum hydroxide, aluminum oxide, calcium carbonate and barium sulphate are used suitably for a diffusion agent. As for the diffusion-filmlike substance, the diffusion agent is mixed with an identical material with a transparent resin plate and dispersed, which is stretched in the direction of either one axis or two. As the diffusion-filmlike subject having homogeneity, uniform thickness and strength can be obtained, sticking operation to the transparent resin sheet is easy, and a transmitting type screen having contrast whose diffusion of light is favorable and having high resolving-power is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a transmission screen, and more particularly to a method for manufacturing a transmission screen having a diffusion layer.

A transmission screen is a projection screen that allows the image to be observed by transmitting the image light from the projector received on the projection surface to the observation surface, and is equipped with a microfilm reader,
It is widely used as reader printers, computer terminal displays, and even prozoexicon television screens.

Transmissive screens used in the following applications must have high resolution so that fine images such as medium-definition and high-definition images can be observed.

That is, it is required to be a transmissive screen that has higher resolution and contrast than a general projection screen, and has good so-called light diffusion distribution characteristics so that light is uniformly distributed over the observation area.

The resolution indicates the number of lines per 1 myon that can be read on the screen, and is preferably several lines per 1 myon. Coni/Trust indicates the reproducible density range of the image projected on the screen and preferably has high diffuse transmittance and low diffuse reflectance.

Conventional transmission screens with a diffusion layer include coated types in which a light-diffusing paint is applied onto a transparent substrate, and dispersion types in which a dispersant is distributed within a transparent substrate. ] Ru.

This dispersion screen generally has a large amount of glare, and in order to reduce this, the number of diffusion particles per unit area of the dispersant, so-called particle density, is increased. This reduces glare, but the diffusion properties are improved so much that the image becomes dark, the resolution is reduced, and the reflectance is increased, causing the drawback that the contrast of the image on the screen is significantly reduced due to the flare component.

The relationship between the thickness of the diffusion layer and the resolution can be determined by the degree of spread of a point image due to internal scattering of light passing through the diffusion layer in which a light diffusing agent is mixed in the medium. In other words, there are two types of diffusion layers that have the same light diffusion properties as a whole; one type has low diffusion per unit thickness of the diffusion layer but has a large layer thickness, and the other has diffusion per unit thickness of the diffusion layer. The former has a larger spread of point images, and therefore has lower resolution than the latter.

In other words, it can be said that the thickness of the diffusion layer is related to the resolution.

As mentioned above, the resolution is only a few lines per frame, so the resolution is about 1-2. For this purpose, the thickness of the diffusion layer must be approximately 50
In the type that applies the diffusion paint containing the above-mentioned diffusing agent, it is difficult to make the thickness of the d1 coating layer constant, but at the same time it is difficult to eliminate unevenness in brightness. The coating layer has the drawback of being easily peeled off and cracked, making it difficult to obtain a screen that is durable and has stable optical properties.

In addition, type 0, which distributes a diffusing agent on a transparent substrate,
It is very difficult to uniformly distribute the dispersant to a depth of about 500μ from one side of some thin layer parts of the transparent substrate, such as fc. There is a drawback that the plate warps due to filling.

Transmissive screens using diffusion films obtained by calendering or extrusion methods have also been proposed.
It is very difficult to produce a film with less unevenness in transmitted light and a lower amount of mineral deposits. It is an object of the present invention to provide a method for manufacturing a transmission screen having a diffusion layer.

According to the present invention, there are two steps: forming a thin diffusion film by uniformly mixing a light diffusing agent and stretching a synthetic resin sheet in uniaxial or biaxial directions, and converting the diffusion film into a transparent resin sheet. A method for producing a transmission screen is provided, which includes the steps of: laminating and heating] and unifying the film.

By the method of the present invention described above, it is relatively easy to uniformly disperse a diffusing agent in a relatively thick synthetic resin sheet, and by stretching this, a thin film-like material of about 50.0 μm is manufactured. Then, since the diffusing agent is distributed more densely and with good orientation, a diffusing film with very good resolution, contrast, and excellent light diffusing properties can be formed.

Furthermore, since a strong diffusion film with a uniform thickness can be produced by stretching, it is easy to attach the film to a transparent resin sheet, and it is also possible to obtain a transmissive screen with good light diffusivity, contrast, and high resolution. Do J.

When producing a diffusion film by stretching a synthetic resin sheet (17), depending on the type of diffusion agent, phantoms may occur at the interface between the diffusion agent and the medium resin during stretching of the synthetic resin sheet.
Air bubbles may form.

However, in the present invention, since the diffusion film-like material is laminated on the transparent resin sheet and then heat-pressed to be integrated, these air bubbles can be completely eliminated by the heat-pressing.

The invention will be described in detail below by way of example and with reference to the accompanying drawings.

FIG. 1 shows an example of a transmission type screen manufactured according to the present invention, in which a diffusion film-like material 2 is integrally attached to the soil surface of a colorless transparent resin sheet 1 using a hot press.

Preferred examples of the transparent resin sheet include methacrylic resin plates, vinyl chloride resin plates, and polycarbonate resin plates. As the diffusing agent, silicon oxide, aluminum hydroxide, aluminum oxide, calcium carbonate, barium sulfate, etc. are preferably used. The diffusion film is preferably manufactured by mixing and dispersing the above-mentioned diffusing agent into the same material as the transparent resin plate and stretching the mixture in the -axis or biaxial direction. However, the diffusion film-like material may be manufactured using a resin sheet material different from the transparent resin sheet.

For example, a diffusion sheet may be obtained by stretching a vinyl chloride resin sheet, and this may be attached to a methacrylic resin sheet.

FIG. 2a FIG. 6 illustrates another embodiment of the invention,
Diffusing film-like material 2 consists of two transparent resin sheets) 18.1b
They are sandwiched between them and integrated using a heated press.

FIG. 2b is a modification of the example shown in FIG. 2a;
One of the transparent resin sheets) 1a and 1b is a colored transparent resin sheet) 1a. Note that both of the two transparent resin sheets la and ib may be colored transparent resin sheets.

Furthermore, FIG. 6a illustrates still another example of the present invention, in which a lenticular lens 1f13 is attached to the outer surface of one transparent resin sheet 1a that holds the diffusion film-like material.
At the same time, a Fresnel lens surface 4 is formed on the outer surface of the other transparent resin sheet 1b.Since the lenticular lens surface 3 can provide vertical and horizontal directionality, it can be used as a screen for large projection televisions. It can be suitably used as

FIG. 6b shows a modification of the example shown in FIG. 6a, in which a colored transparent resin sheet is used as the transparent resin sheet 1a on which the lenticular lens surface 3 is provided.

FIG. 4 further illustrates another example of the present invention, in which the upper surface of one transparent resin sheet 1 is a Fresnel lens surface 4, the lower surface is a lenticular lens surface 3, and this lenticular lens surface 3) The lume-like material 2 (diffused into 3) is integrated by heat pressing. It is said that this method can supplement the light diffusivity of a diffusion film or prevent light from entering the surface.

Example 5% of silicon oxide having an average particle size of 4 μm was added as a diffusing agent to a partially polymerized MMA resin composition to produce a cast sheet with a thickness of 2.7 stripes. The concentration of the diffusing agent at this time was 160
g/ca.

Next, this cast sheet was heated at 180° C. for 20 minutes and stretched in biaxial directions to obtain a diffusion film with a thickness of 0.4 mm. In this state, due to the separation of the diffusing agent and the resin medium, the diffusing film foams and becomes cloudy and completely white. The concentration of the diffusing agent in this state is 26 g/-.

As shown in FIG. 6a, this diffusion sheet-like material 2 has a lenticular surface 3 on its outer surface, has a total light transmittance of 80% by adding an organic dye (alinine black), and has a thickness of 2 mm. It is sandwiched between a methacrylic resin sheet 1a and a transparent methacrylic resin sheet 1b having a thickness of two inches and having a Fresnel lens surface 4 on its outer surface. In this state, with a heating temperature of 180°C and a pressure cuff of 0kg/Cd,
A transmission screen was formed by hot pressing.

The cloudy state after hot pressing is alleviated, and a suitable light-diffusing layer is formed.

Is it better than that? +/In this transmission type screen, the pitch of the lenticular lens surface is set to 0.7 mm and the radius of curvature is 0.7 mm.
When the angle was set to 5mi and 7, the jerk gain was 11.6 half-value angle α, 20 degrees, and the 1/3 angle was 26 degrees.

[Brief explanation of drawings]

FIG. 1-1 is a partial sectional view illustrating an example of a transmission screen manufactured by the method of the present invention. Figures 2a and 2b illustrate, in partial cross-section, another example of a transmission screen manufactured by the method of the invention; Figures 3a and 3b illustrate, in partial cross-section, another example of a transmission screen manufactured by the method of the invention. FIG. 4 is a partial sectional view illustrating yet another example of a transmission screen manufactured by the method of the present invention. 1, la, Ib...Transparent resin sheet 2...
Diffusion film-like material 3... Lentiki Kohler lens surface 4...
・Fresnel lens surface representative Asamura Kōgai 4 peopleFigure 1Fang 2bFigureFang 3bFigure 2oFigure IIP3aFigure 4

Claims (1)

[Claims] (1) In a method for manufacturing a transmission screen, (a) a synthetic resin sheet uniformly mixed with a light diffusing agent is stretched in the -axis or biaxial direction to produce a thin diffusion film-like material. (b) A step of laminating the diffusion film-like material with a transparent resin sheet and heat-pressing them to integrate them. (2. The method for manufacturing a transmission screen according to claim 1, wherein the transparent resin sheet is a colored transparent resin sheet. (3) Patent The method for manufacturing a transmission screen according to claim 1 or 2, characterized in that the diffusion film-like material is sandwiched between the two transparent resin sheets. (4) In the method for manufacturing a transmission screen according to claims 1 to 3, a lens surface such as a Fresnel lens or a lenticular lens is formed on the surface of the transparent resin sheet. (5) In the method for manufacturing a transmission screen according to any one of claims 1 to 4, the transparent A method for manufacturing a transmission screen characterized by forming fine irregularities on the surface of a resin sheet.