JPH01293334A - Transmissive screen and projection image display device using the transmissive screen - 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 the Invention The present invention relates to a large-area, high-resolution transmission screen and a projection-type image display device using the transmission screen.

2. Description of the Related Art In order to obtain a large-screen image, a method is well known in the art in which a relatively small image is enlarged using a projection lens and projected from the rear onto a transmissive screen. Projection devices that apply this method include slide projectors, CR
There are projection type image display devices using T, projection type image display devices using light valves, etc.

The optical properties required for a transmissive screen include a bright projected image, wide viewing angle, high resolution, and low double images and reflections, and the mechanical properties include It is required to have a large area, sufficient mechanical strength, and no warping.

Transmissive screens of this type include those with a matte surface like frosted glass, those with light-scattering particles dispersed in a transparent binder and coated on a transparent plate, and those with light-scattering particles dispersed on a transparent sheet or transparent plate. It is known that the
For example, Japanese Patent Publication No. 58-15762). Furthermore, a transmission type screen is known in which a Fresnel lens is formed on the outer surface of a transparent plate in order to brighten the peripheral area of a projected image.

The transmissive screen targeted by the present invention has a large effective display area of 1 m square, high resolution of 4 lines/fin, and a suitable viewing angle of approximately ±3C degrees. Specifically, a light diffusing plate in which light scattering particles are dispersed in a transparent plate is used as a transmission screen. In such a light diffusion plate, the light scattering particles that control the light distribution characteristics are dispersed inside the base material, so even if the mechanical or chemical properties of the outer surface change, the light distribution characteristics will not change over time. It is characterized by very small changes. A transparent resin material such as acrylic resin or vinyl chloride is used as the base material of the light diffusing plate, and a material such as silica having a refractive index different from that of the base material is used as the light scattering particles.

When trying to set the appropriate viewing angle of the diffuser plate to ±30 degrees and the resolution to 4 lines/dragon, the plate thickness will range from 0.2 fl to 2 fl, and if the effective display area is as large as 1 m square, Mechanical strength is insufficient. In order to obtain sufficient mechanical strength, a configuration in which a light diffusing plate and a translucent plate for reinforcing mechanical strength are bonded together can be considered.

Problems to be Solved by the Invention Generally, resin materials have the property of expanding and contracting significantly due to changes in temperature and humidity. When a light diffusing plate and a translucent plate are bonded together, if the magnitude of expansion and contraction differs between the light diffusing plate and the translucent plate, a problem inevitably arises in that the entire transmissive screen is warped.

If the screen is extremely warped, the resolution will deteriorate and the user will feel uncomfortable, which is a big problem.

The present invention has been made in view of these points, and an object of the present invention is to provide a large-area transmission screen that has high resolution, sufficient mechanical strength, and is resistant to changes in temperature and humidity. It is an object of the present invention to provide a projection type image display device that uses a transmission type screen, has a large area, has high resolution, and has less discomfort.

Means for Solving the Problems In order to solve the above problems, the transmission screen of the present invention has a light diffusion plate and a translucent plate optically coupled over the entire effective display area, and the light diffusion screen A transparent elastic body is provided between the plate and the translucent plate.

Silicone rubber compounds, especially 2
It is preferable to use a silicone rubber compound that hardens into a gel-like state by an addition reaction after liquid mixing, or a silicone rubber compound that hardens into a gel-like state by ultraviolet irradiation.

Spacer means may be included in the adhesive to ensure that the transparent elastic body has a predetermined thickness. Also,
An elastic transparent sheet may be sandwiched between the light diffusing plate and the light-transmitting plate, and the light-diffusing plate, the transparent sheet, and the light-transmitting plate may be bonded by heat fusion or an adhesive.

It is desirable that the thickness of the spacer means or the transparent sheet be approximately the same as the dimensional difference in expansion and contraction of the light diffusing plate and the transparent plate.

Furthermore, high image quality can be achieved by forming a Fresnel lens on the light-transmitting plate and by making the outer surface of the light diffusing plate matte.

The projection type image display device using the above-described transmission screen can provide a projected image with a large area, high resolution, and less discomfort.

Effects According to the above structure, the light diffusing plate and the transparent plate have sufficient thickness, so sufficient mechanical strength can be obtained, and the light diffusing plate and the transparent plate can also be damaged due to changes in temperature or humidity. Even if there is a dimensional difference between the two sides, the elastic body easily deforms according to the dimensional difference, so the warpage of the transmission screen can be minimized.

Embodiment An embodiment of a transmissive screen and a transmissive image display device using the transmissive screen according to the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows the configuration of a transmission screen in an embodiment of the present invention, in which 1 is a light diffusing plate, 2 is a transparent plate, and 3 is a transparent screen.
5 is a transparent elastic body, and 5 is a Fresnel lens. The transmission screen of the present invention has a structure in which a light diffusing plate 1 and a transparent plate 2 are optically coupled by a transparent elastic body 3. Translucent plate 2
An image display device is placed on the side, and an observer is placed on the light diffusion plate 1 side.

The light diffusing plate 1 is made of acrylic resin as a base material with silica dispersed therein as light scattering particles, and the outer surface 4 is processed into a matte shape to prevent reflections.

The external dimensions of the light diffusing plate 1 are 755 layers long, 755 m wide, and 2 mm thick.

The transparent plate 2 is an acrylic resin plate, and a Fresnel lens 5 is formed on its outer surface. fresnel lens 5
acts as a field lens and bends the light incident on the periphery of the Fresnel lens 5 in the direction of the viewer.
The peripheral area is also made to appear brighter to the viewer. The external dimensions of the light-transmitting plate 2 are 755 m long, 755 m wide, and 2 mm thick, which are the same as the light diffusing plate 1.

A transparent elastic body 3 is arranged between the light diffusion plate 1 and the transparent plate 2 over the entire effective display area, and this transparent elastic body 3 is in close contact with the light diffusion plate 1 and the transparent plate 2. . The transparent elastic body 3 uses an i3-mei silicone rubber compound that hardens into a gel-like state by an addition reaction over time or by heating after mixing the two liquids. It is also possible to use a transparent silicone rubber compound that hardens into a gel-like state upon irradiation with ultraviolet light.

A gel-like silicone rubber compound has the property of not breaking even if it is stretched more than twice as much.

In addition, the refractive index of the transparent elastic body 3 is the same as that of the light diffusing plate 1 and the transparent plate 2.
It is only slightly smaller than the acrylic resin used in Transparent elastic body 3
The thickness of the peripheral part is 0.5n+.

A method for optically coupling the light diffusing plate 1 and the transparent plate 2 using a silicone rubber compound that hardens into a gel-like state by an addition reaction after mixing two liquids as the transparent elastic body 3 will be described. A light-transmitting plate 2 with a spacer of 0.5 mm thick attached to the periphery is placed horizontally, an uncured liquid of silicone rubber compound is applied on it, and a light-diffusing plate 1 is placed on top of it with the convex side facing downward. Gently stack them one on top of the other, starting from the edge and bending it slightly so that it looks like this. Thereafter, the light diffusing plate 1 is pressed down to push out air bubbles contained in the uncured silicone rubber compound, and left in that state.

When a predetermined period of time has elapsed in this state, the silicone rubber compound hardens into a gel-like state due to an addition reaction, and at the same time exhibits adhesive strength to firmly adhere to the light diffusing plate 1 and the transparent plate 2. The 0.51n spacer may be removed last.

The transmission screen made by the above method was heated to 60°C.
I placed it under conditions of 90% humidity and 20°C and 20% humidity. In this case, the dimensional difference between the diffuser plate 1 and the light-transmitting plate 2 was 0.5 n at the maximum, and the amount of movement of the center part was 2 mm at the maximum. This degree of warpage poses no practical problem. In addition, when the light diffusing plate 1 and the translucent plate 2 were partially bonded with an adhesive with the same dimensions, the movement amount of the center part was a maximum of 20 cranes, confirming the effect of the present invention. It was done.

If the peripheral portion of the transparent elastic body 3 is too thin, the transparent elastic body 3 may peel off from the light diffusing plate 1 or the light-transmitting plate 2. Peeling of the transparent elastic body 3 tends to occur in the peripheral area,
This is particularly likely to occur when the peripheral area is thin. If the transparent elastic body 3 becomes too thick, the Fresnel lens 4 and the light diffusing plate are separated from each other, resulting in a decrease in resolution. In the end, it appears that the thickness of the transparent elastic body 3 should be approximately the same as the dimensional difference between the light diffusing plate 1 and the transparent plate 2 due to expansion and contraction.

Next, a projection type image display device using the transmission type screen shown in FIG. 1 will be explained. It is shown in Figure 3. A transmission screen 1O is arranged on the front side of the cabinet 9, a projector 1) is arranged on the upper part, a first mirror 12 is arranged on the lower front side, and a second mirror 13 is arranged in the center. As the projector 10, a slide projector or an image display device using high-resolution light pulp can be used. The transmissive screen 10 has an effective display area of 730 mm in height and 7 mm in width.
There are 30 cranes.

Since a transmissive screen is used that has high resolution and is resistant to changes in temperature and humidity, it is naturally possible to obtain a projected image with high resolution and little discomfort. Furthermore, since a transmissive screen reduces contrast due to external light less than a reflective screen, a high-quality projected image can be obtained even in a bright environment.

Another embodiment of the present invention will be described.

As shown in FIG. 2, a thin elastic transparent sheet 6 is sandwiched between the light diffusing plate 1 and the transparent plate 2, and the light diffusing plate 1, the transparent sheet 6, and the transparent plate 2 are bonded together by transparent adhesive. It is fixed with material 7.8. Vinyl chloride can be used as the transparent sheet 6. The aforementioned silicone rubber compounds can also be used as adhesive 7.8. Instead of adhesion, the light diffusing plate 1, the transparent sheet 6, and the light-transmitting plate 2 can also be bonded together by thermal fusion.

In the configuration shown in FIG. 1, beads of transparent resin may be dispersed in the transparent elastic body 3 in order to maintain the distance between the light diffusing plate 1 and the transparent plate 2.

Effects of the Invention Since the present invention is configured as described above, it produces the effects described below.

The transmissive screen of the present invention has sufficient mechanical strength because the light diffusing plate and the translucent plate have a sufficient thickness. In addition, even if there is a dimensional difference between the light diffusing plate and the translucent plate, the elastic body easily deforms according to the dimensional difference, so the warping is very small, and therefore, due to changes in temperature or humidity, There is no deterioration in resolution, and there is no sense of discomfort.

Furthermore, by using this transmissive screen, it is possible to provide a projection type image display device that projects images with high resolution and less discomfort.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the configuration of a transmission screen in an embodiment of the present invention, FIG. 2 is a sectional view showing the configuration of a transmission screen in another embodiment of the invention, and FIG. 1 is a schematic configuration diagram showing the configuration of a projection type image display device using the transmission screen shown in the figure. l...Light diffusing plate, 2...Translucent plate, 3
......Transparent elastic body, 5...Fresnel lens, 6...Transparent sheet, 10...Transmission screen, 1)...Projection vessel. Name of agent: Patent attorney Toshio Nakao Haka1 person 1 -m-
Destination m Section Slope 2...-Light exposure board I-・Light exposure board 6-...Up to Ming sheet IO-Difference 'Ik Ji screen

Claims (10)

[Claims] (1) A transmission screen in which a light diffusion plate and a light-transmitting plate are optically coupled over the entire effective display area, and a transparent elastic body is provided between the light diffusion plate and the light-transmitting plate. Transparent screen. (2) The transmission screen according to claim (1), wherein the transparent elastic body is a transparent silicone rubber compound. (3) The transparent elastic body is a material that hardens into a gel-like state through an addition reaction after mixing two liquids.
) Transmissive screen according to any one of the above. (4) The transmission screen according to claim 1 or 2, wherein the transparent elastic body is a material that hardens into a gel-like state when irradiated with ultraviolet rays. (5) The thickness of the peripheral portion of the transparent elastic body is approximately the same as the dimensional difference due to expansion and contraction between the light diffusing plate and the transparent plate.
1) Transmissive screen as described. (6) The transmission screen according to claim (1), wherein the transparent elastic body includes transparent spacer means therein. (7) The transmission screen according to claim (1), wherein a Fresnel lens is formed on one of the translucent plates. (8) The transparent elastic body is a transparent sheet having elasticity,
2. The transmission screen according to claim 1, wherein the light diffusing plate, the transparent sheet, and the light-transmitting plate are bonded to each other by a transparent adhesive or heat fusion. (9) The transmission screen according to claim (1), wherein the outer surface of the light diffusing plate is matte. (10) A transmissive image display device using the transmissive screen according to claim (1).