JPS5846336A - Transmissive screen - Google Patents

Abstract

PURPOSE:To obtain a transmissive screen which has a wide directional angle and is superior in hue, by using a resin medium where a diffusing agent is mixed and providing a specific lenticular lens on the face of the observation side. CONSTITUTION:A lenticular lens, where many lenses 2 whose sections are perfectly round are arranged to satisfy relation P/R<1.7 (R is the radius of the curvature of the lens and P is pitches between lenses), is provided on the face of the observation side of a medium 1 consisting of a methacrylic resin where a diffusing agent (such as an SiO2 powder and glass beads) is mixed, thus forming a transmissive screen. Otherwise, the lenticular lens consisting of said lenses 2 is provided on the observation side of the resin medium 1 where the diffusing agent is not mixed, and a resin medium layer 4 where the diffusing agent is mixed is provided on the opposite side.

Description

[Detailed Description of the Invention] The transmissive screen is a screen that projects Eirin using a projector installed on the back, and can be used as a reader for microfilm, a reader printer, a computer terminal display, and a screen for Glojexion TV. It is widely used as The performance required for such a transmissive screen is: ■ The ability to obtain a wide viewing angle ■ Few color spots in the left and right directions and color changes depending on the viewing position ■ Good image contrast (4) Good resolution ■ High gain, etc.

Recently, devices have been developed that magnify the image of a color television and project it onto a screen, but in order to maintain the brightness of the image from the projector, these devices use the three primary colors of light, red, 3CRT-3 lens system or 5C using a projection tube and projection optical system that emit green and blue light
It is projected onto a screen using the RT-2 lens system.

That is, in the 5-3CRT-5 lens system shown in FIG. 1, 5cnTs of red (0), green (b), and blue (-) and a projection lens are arranged as shown in the figure for projection. However, when viewing screen 0 using this method, not only is there a difference between the brightness seen from the front position and the brightness seen from an oblique position, but also because the projection angles of each color of light are different from each other. When viewed at each position (A'), (0'), and (Noi), different colors are observed. This phenomenon cannot be avoided with a system using a plurality of projection lenses.

One way to eliminate this phenomenon as much as possible is to widen the directivity of the screen.

The present invention aims to widen the directivity angle of the screen. Conventionally, methods for expanding the directivity of a screen include forming lenticules on the screen or forming a layer of a diffusing agent on the screen.

In view of this current situation, the present invention was completed as a result of studying a wide directivity angle for a Motta transmission screen.
The gist of this is that it is a transmission screen that uses methacrylic resin as a medium, and consists of a lenticule in which many lenses with a perfect circular cross section are formed on the observation side, and the pitch P and curvature of the screen are The radius ratio is t
4<P/'R<t is within the range of 7, and the medium is mixed with a diffusing agent or is in a clean containing a diffusing agent.

Hereinafter, one embodiment of the present invention will be explained with reference to the drawings starting from FIG. 2 showing an embodiment.

FIG. 2 shows an embodiment of the transmission screen according to the present invention, in which (1) is a medium made of methacrylic resin, (
2) is a lens provided on the observation side surface, and (3) is the light source side surface. P is the pitch in the lens,
R is its radius of curvature. In the figure, ) is the area through which light is transmitted when it enters from surface (3), and (g) is the area of interface reflection.

(In addition, in the same figure and FIGS. 3 to 5, the illustration of the diffusing agent is omitted for convenience of explanation.) Next, based on FIG. 3, the pitch P and radius of curvature R of the lens in the lenticular I will explain the relationship with (
2) shows a piece of lenticular lens. Light 0 parallel to the optical axis is incident from the direction of the current plane (3),
When the light is emitted to the lens surface (2) side, the following relationship (1) holds true in a perfectly circular lenticular lens.

R51nθ=tan・・・・・・(1) where θ is the incident angle and n sinθ==sinψ・・・・・・(2
) However, since n is the refractive index of the medium, if the refraction angle ψ=906, then equation (1) can be rewritten as follows.

P=-R・・・・・・(3) In order to make the directivity angle thicker, it is sufficient to increase the pitch P when the radius of curvature R is constant, but the relationship of equation (3) Therefore, it was thought that if the pitch was set near the refraction angle ψ=9Q', the loss due to interfacial reflection would increase, and the transmitted light cover of the screen would be extremely reduced. However, it has been found that when a lenticule within the scope of the present invention is used, the directivity angle is expanded even when interface reflection loss is taken into account. As shown in Figures 4 and 5, the optical power incident on the area exceeding the critical angle is reflected by the lens surface (2), returns to the medium (1), and then is reflected by the surface (3). The light is emitted toward the lens surface (2) due to the effect of the diffuser. Therefore, in the conventional way of thinking, only the light in the area corresponding to the area corresponding to the surface of the surface area) is transmitted, and the light in the area of interface reflection (a) is considered to be lost, making this area J~ smaller than the condition where the critical angle disappears. It was designed like that. However, it has been found that when the force is changed according to the present invention, a part of the light from the above-mentioned interface reflection area can be effectively used, and the directional force can be improved as shown in FIG.

The medium (1) of the present invention, methacrylate-based material, includes methyl methacrylate σ) polymer or &ethyl methacrylate 90% by weight or more and other copolymerizable monoethylenically unsaturated compounds and/or Alternatively, a copolymer with a polyfunctional compound is used. Examples of methods for manufacturing the spoon include extrusion molding, hot press molding, and injection molding.

Further, in the present invention, a diffusing agent is also used as a method of widening the directivity angle (t) in the vertical direction. Diffusing agent and Shiteha,
3102, CaCO3, All OB, Ti01
.

Inorganic diffusing agents such as BaSO4, ZnO, glass pieces, or f”Ky-710 manufactured by Rohm & Rivers
One or more types of organic diffusing agents such as `` are used,
This diffusing agent is uniformly mixed and distributed in the methacrylic resin of the medium (1), or a layer containing these diffusing agents is formed.

Figures 6) to 0) show examples of the transmission type screen of the present invention. In Figure 6), a lens (2) is formed on the viewing side and a diffusing agent is mixed in the medium (1). (Example shown in Figure 6)
6 is an example in which a layer (4) containing a diffusing agent is formed on the surface (3).
Figure (C) has the same configuration as the one in Figure 6, and the surface (fake with the Fresnel lens (5) integrally formed on the third side, in Figure 6) is different from that in Figure 6 (G). This is an example of a screen made by combining Fresnel lenses (6) on the body.

The shape of the lenticular in the present invention is generally one in which a large number of semicylindrical lenses are arranged as shown in the figure, but it is also a lens in which a large number of independent parts called a fly's eye lens are arranged. Good too.

Specific examples will be described below.

Example 1 In manufacturing a transmission screen as shown in Fig. 2,
Methacrylic resin plates with different gains were obtained by changing the eagle of Sin for the methacrylic resin. This methacrylic resin plate was heated and pressed in a mold having a P of 1.0 days and an R of 0.62 rm to obtain a transmission type screen as shown in Table 1. Note that the ratio P/R at this time is 161.

This is the gain ratio in Table 1 and is used as a guide when measuring changes in brightness.

As shown in Table 1, by using the shape of the present invention, even if the peak gain value changes, the β value maintains a high level of 276 or more, and it was confirmed that the directivity is excellent. .

Example 2 A transparent screen containing sio and having the shape shown in Table 2 was prepared by a method similar to that of Example 1.

In addition, sample No. at this time.

All of the silica contents No. 6 to No. 11 were prepared in combination with Sample No. 5 of Example 1 above.

As shown in Table 2, Sample 6.7 of the present invention has β
A value of 250 or more is obtained, indicating good directivity, and the brightness ratio is around 3 or below.

Note that Samples 8 to 11, which were comparative products, had a β value of about 22' or less, and a brightness ratio of 5 or more, which was not preferable.

Although the above two examples have been described, further explanation will be given based on the data shown in these examples.

Figure 7 is a graph showing the viewing characteristics of sample No. 90, which is a product of the present invention, and sample No. 90, which is a comparative product.
In the case of , the peak gain is slightly lower, but even if the angle from the center is wide, the amount of light does not decrease, confirming that the product of the present invention has excellent directional characteristics.

FIG. 8 is a graph showing the relationship between P/IR and β value of the transmissive screens in the range of products of the present invention (sample Nos. 1 to 5), and shows the relationship between the P/IR and β value of the transmissive screens in the range of products of the present invention (sample Nos. 1 to 5). It can be seen that the β value is at a high level.

Furthermore, FIG. 9 is a graph showing the brightness ratio of each sample in the above embodiment. The smaller the brightness ratio is, the more uniform it will be and the less color change will occur.

According to the inventor's studies, a brightness ratio of about 3 or less is preferable for the performance of a transmissive screen, and when expressed as a ratio of pitch to radius of curvature, it falls within a range of more than 14 and less than 17. Therefore, it is preferable to design the lenticular by finding P/R within this range. The transmissive screen of the present invention having such a design has improved directional characteristics, and as a result, color changes in the left and right directions are reduced, resulting in further improved performance.

[Brief explanation of the drawing]

Figure 1 is a plan view showing an overview of a 3CRT-3 lens type color projection TV, Figure 2 is a plan view showing an embodiment of the transmission screen of the present invention, and Figures 3 to 5 are light transmission states. Explanatory diagram for explaining, Fig. 6 (A) ~ 0)
7 is a sectional view showing an example of the transmission type Surclean of the present invention.
The figure is a graph showing the directivity characteristics of the example product of the present invention and the comparative product. Figure 8 is a graph showing the relationship between P/R and β value of the example product of the present invention. Figure 9 is a graph showing the relationship between PA and luminance ratio. It is a graph showing a relationship. (1)・・・・・・Medium (2)・・・・・・Lens surface (3)・・・・・・ Surface curtain on the light source side/Figure 2 PX-Example Button 3 Figure Tail 5 Continued from page 1 0 Inventor: Ryuji Kondo, Tokyo 6-7-35, Parts and Graphics, Sony Corporation 0 Inventor: Yasuyoshi Sugii, Tokyo, Parts and Illustrated Products, 6-7-35, Sony Corporation Within the company ■Applicant: Sony Corporation Tokyo Parts and Graphics 6-7-35

Claims (1)

[Claims] A Lentiki error caranary, which is a transmission screen using a methacrylic resin as a medium, in which a large number of perfectly circular lenses are formed on the observation side, the ratio of the pitch P and the radius of curvature R of the lenses, t 4 (P/R<17), and a transmission screen characterized in that a diffusing agent is mixed in the medium or a layer containing a diffusing agent is formed.