JPH02251945A - Transmission type screen and projection type image display device using same - Google Patents

Abstract

PURPOSE:To project an image of excellent quality which is close to an image obtained when a video tube is viewed directly by providing a light absorber in a light transmissive plate or nearby an observer-side surface. CONSTITUTION:A light diffusion plate 5 or lenticular plate 7 easily reflects external light by a light diffusing means because the directivity of external light reflection is wide, but the light transmissive plate 6 has the narrow directivity of external light reflection and is harder to reflect the external light than the light diffusion plate 5 or lenticular plate 7 because the projection surface of the plate 6 is plane. The light transmissive plate 6 has the light absorber internally or nearby the observer-side surface, so the original brightness of the image decreases, but the external light passes through the light transmissive plate 6 twice, so the light intensity decreases greatly, so that the contrast becomes better correspondingly. Consequently, the image of excellent quality which is close to the image obtained when the video tube is viewed directly is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a transmissive screen that projects an image from the rear, and a projection image display device using the transmissive screen.

2. Description of the Related Art In order to obtain a large-screen image, it has been well known to project an image onto a relatively small picture tube and then enlarge and project the image onto a screen using a projection lens. Recently, transmissive screens that project images from the back have been widely used because they can be used even in bright rooms.

An example of the conventional configuration of such a transmissive screen is shown in the sixth section.
It is composed of a Fresnel lens plate 1 and a lenticular plate 2 as shown in the figure, and is simply stacked with a Fresnel lens 3 and a lenticular lens 4 facing each other. A Fresnel lens plate 1 is placed on the projection lens side, and a lenticular plate 2 is placed on the viewer side. The Fresnel lens plate 1 converts the diverging light from the projection lens into nearly parallel light to make the peripheral area appear brighter to the viewer. The lenticular plate 2 is a translucent plate in which light scattering particles are dispersed, and lenticular lenses 4 in which the longitudinal direction of one element is oriented vertically are arranged on the surface of a transparent plate with light scattering particles dispersed therein. This is to widen the viewing angle in the horizontal direction without increasing the angle.

There is also one in which a light-absorbing material is applied in stripes on the area of the lenticular plate 2 on the side of the viewer through which light does not pass.

Problems to be Solved by the Invention Conventionally, the image obtained by enlarging and projecting the image projected on a picture tube onto a transmission screen using a projection lens is inferior in quality to the image obtained when looking directly into the picture tube. That was the evaluation. The image source for both is the same picture tube, and although recent transmissive screens have considerably improved performance in terms of resolution, viewing angle, contrast, etc., the above evaluation remains the same.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a transmission type screen that can provide an image similar to that obtained when looking directly into a picture tube. It is an object of the present invention to provide a projection type image display device that can obtain an image similar to that obtained when viewing a tube directly.

Means for Solving the Problems In order to solve the above problems, the transmission screen of the present invention includes a light diffusion plate that includes a light diffusion means that converts narrow directional light into wide directional light and transmits it; and a light-transmitting plate disposed on the observer's side, the light-transmitting plate having a planar exit surface and a light-absorbing material inside or near the observer's side.

Further, the transmission screen of the present invention includes a lenticular plate having a lenticular lens formed on an incident surface, and a τ transparent plate disposed on the viewer side of the lenticular plate, and the transparent plate is It does not include a light diffusing means, has a planar output surface, has a light absorber inside or near the output surface, and combines the lenticular plate and the transparent plate.

The above-mentioned transmission screen can be used in a projection type image display device.

Effect According to the above structure, the light diffusing plate or lenticule easily reflects external light because the light diffusing means has a wide directionality of reflecting external light, but the light-transmitting plate has a planar exit surface. Therefore, the directivity of external light reflection is narrow, and it is difficult to reflect external light than a light diffuser plate or lenticular plate.Also, a translucent plate has a light absorbing agent inside it or near the side of the viewer, so it is inherently difficult to reflect external light. Although the brightness of the image decreases, since the external light passes through the translucent plate twice, the light intensity is greatly attenuated, and the contrast improves accordingly.

EXAMPLE Hereinafter, an example of a transmission screen according to the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows the configuration of a transmissive screen in an embodiment of the present invention, in which 5 is a light diffusing plate, 6 is a transparent plate, and 7 is a transmissive screen.
8 is a lenticular lens, and 8 is a Fresnel lens.

A light diffusing plate 5 is placed on the projector side, and a translucent plate 6 is placed on the viewer side.

The external dimensions of the transparent screen are 636 cm long and 839 cm wide.
It is a temple. The light diffusing plate 5 has a lenticular lens 7 formed on the viewer's side of an acrylic resin plate mixed with a light diffusing agent.
A Fresnel lens 8 is formed on the other surface, the thickness is 3 mm, and the pinch of the lenticular lens 7 is 11 mm.
The pitch of the 1111 Fresnel lens 8 is 0.14 mm.

The translucent plate 6 is an acrylic resin plate with a light absorbing agent mixed therein, and the side surface 9 facing the viewer is a flat glossy surface. The transparent plate 6 has a thickness of 2III11, an average transmittance in the visible region of about 70%, and has spectral transmittance characteristics as shown in FIG.

With the configuration shown in FIG. 1, the light diffusing plate 5 has a wide directivity for reflecting external light, so it is easy to reflect external light, but the light-transmitting plate 6 has a planar output surface 9. Because of this, the directivity of external light reflection is narrow, and it is difficult to reflect external light compared to the light diffusing plate 5. Furthermore, although the light absorbing agent inside the translucent plate 6 reduces the original brightness of the image, since the external light passes through the translucent plate 6 twice, the light intensity is greatly attenuated, and the contrast is reduced accordingly. Get better. When the viewer side surface 9 of the translucent plate 6 is a glossy surface, a glossy appearance is generated in the projected image, and an image quality close to that obtained when viewing directly through the video tube is obtained.

By making the observer side surface 9 of the transparent plate 6 flat, the area where unpleasant reflections can be seen can be reduced.

Visible region of translucent plate 6 (3800n+w~720n cocoon)
It is preferable that the maximum transmittance at is 70% or less.

If it is not 70% or less, the contrast improvement effect will hardly be felt. If the average transmittance is too low, the brightness of the original image will drop too much, so it is appropriate to set the average transmittance to 50 to 70%.

Next, a projection type image display device using the transmission type screen shown in FIG. 1 will be explained. A transparent screen 1 is mounted on the front of the cabinet 10, the schematic configuration of which is shown in FIG.
1, a projector 12 consisting of a video tube and a projection lens is placed at the bottom, a first mirror 13 is placed at the front side of the bottom,
A second mirror 14 is placed in the center. As the projector 12, a slide projector, an image display device using a light valve, etc. can also be used. Light emitted from the projector I2 reaches the transmissive screen 11 via the first mirror 13 and the second mirror 14, and projects an image on the transmissive screen 11. Transparent screen 11
Since the light absorbing agent reduces the reflection of external light, it is possible to provide an image that is easy to see, similar to that of a direct view type image tube.

Other embodiments of the present invention will be described. In either case, it is possible to obtain an image with a quality close to that of the direct view type.

The transmission type screen shown in FIG. 4 consists of a Fresnel lens plate 1
A sheet-like light diffusing plate 17 is pasted on the plane opposite to the Fresnel lens 16 of No. 5, and a transparent plate 18 is placed on top of the light diffusing plate 17.
It is a combination of The light diffusing plate 17 has a light diffusing agent mixed therein, and at the same time, minute irregularities are provided on the light emitting surface 19.

These minute irregularities widen the viewing angle. Translucent plate 18
is the same as that shown in FIG. 1, and the viewer side surface 20 is a flat glossy surface. The minute irregularities of the light diffusing plate 17 also have a light diffusing effect against external light, and when the surroundings are bright, the contrast decreases.

The light absorbing agent of the translucent plate 18 suppresses reflection of external light, and even if the surroundings are bright, an image with good contrast can be obtained. Note that the reason why the light diffusion plate 17 and the light-transmitting plate 18 are not attached with a transparent adhesive or a transparent adhesive is to prevent the light diffusion effect caused by minute irregularities on the surface of the light diffusion plate 17 from being destroyed.

The transmission screen shown in FIG. 5 includes a Fresnel lens plate 21, a lenticular plate 22, and a translucent plate 23 arranged in this order from the projector side.

The Fresnel lens plate 21 has a Fresnel lens 24 on the observer side.
A lenticular lens plate 25 is formed on the projector side of the lenticular plate 22. The lenticular plate 22 has a light diffusing agent mixed therein. 33
The optical plate 23 is the same as that shown in FIG. 1, and the observer side 29 is a glossy surface. Lenticular plate 22
and the opposing surface 26 of the translucent plate 23. ? 7 are both flat, and both are bonded with a transparent adhesive 28. In this way, when the lenticular plate 22 is thin and has weak mechanical strength, the translucent plate 23 can suppress deformation of the lenticular plate 22. The transmission type screen shown in Fig. 5 also has the same effect as the transmission type screen shown in Fig. 1.
Images with good contrast can be obtained.

In the configuration shown in FIG. 5, if a light-absorbing material is applied to the part of the observer-side surface 26 of the lenticular plate 23 through which light does not pass, this light-absorbing material absorbs external light and reduces reflected light. Therefore, it is possible to further reduce contrast deterioration due to external light.

In the configuration shown in FIG. 1, FIG. 4, or FIG. 5, if an anti-reflection film is applied to the observer side surface 9, 20° 29 of the transparent plate 6, 18, 23, reflection of external light can be reduced. can do.

Also, the observer side surfaces 9, 20. of the translucent plate 6.18°23.
Even if 29 is made of a matte surface, reflections can be reduced.

The transmission type screen shown in FIG. 5 can also be used in the projection type image display device shown in FIG. 3, and can provide images with good contrast.

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

Since a light-absorbing material is provided inside the translucent plate or near the side of the viewer, the original brightness of the image is reduced, but the light intensity is greatly attenuated because external light passes through the translucent plate twice. That's how much better the contrast becomes.

Furthermore, by using this transmission type screen, it is possible to provide a projection type image display device that has good image quality and projects an image that is similar to that seen when viewing directly through a video tube.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the configuration of a transmission screen in an embodiment of the present invention, FIG. 2 is a characteristic diagram showing the spectral transmittance of a translucent plate, and FIG. A route map showing a schematic configuration of a projection type image display device using a screen, FIGS. 4 and 5 are sectional views showing the configuration of a transmission type screen in another embodiment of the present invention, and FIG. 6 is a conventional transmission type image display device. FIG. 3 is a sectional view showing the configuration of a mold screen. 5...Light diffusing plate, 6...Translucent plate, 7
......Lenticular lens, 8...Fresnel lens, 11...Transmission screen, 1
2...Projector, 15...Fresnel lens plate, 17...Light diffusion plate, 1B...Translucent plate, 21...・Fresnel lens plate, 22...
...Lenticular plate, 23...Translucent board. Name of agent: Patent attorney Shigetaka Awano Idiot III
Figure diagram layer diagram rakuzu otsugo c! ! November Chi 11 growing chart

Claims (12)

[Claims] (1) A light diffusing plate equipped with a light diffusing means for converting narrow directional light into wide directional light and transmitting the light, and a transparent plate disposed on the observer side, the transparent plate is a transmissive screen that does not contain any light diffusing means inside, has a planar exit surface, and has a light absorber inside or near the exit surface. (2) The transmission screen according to claim (1), wherein the maximum transmittance in the visible region of the spectral transmittance characteristics of the transparent plate is 70% or less. (3) The transmission screen according to claim (1), wherein the light-emitting surface of the light-transmitting plate is a glossy surface. (4) Claim (
1) Transmissive screen as described. (5) Claim (
1) Transmissive screen as described. (6) A projection type image display device using the transmission type screen according to claim (1). (7) comprising a lenticular plate having a lenticular lens formed on an incident surface and a translucent plate disposed on the observer side of the lenticular plate, the translucent plate not including a light diffusing means; A transmission screen having a planar exit surface, a light absorbing agent inside or near the exit surface, and combining the lenticular plate and the translucent plate. (8) The transmission screen according to claim (7), wherein the maximum transmittance in the visible region of the spectral transmittance characteristics of the transparent plate is 70% or less. (9) The transmission screen according to claim (7), wherein the light-emitting surface of the light-transmitting plate is a glossy surface. (10) The transmission screen according to claim (7), wherein the viewer's side surface of the transparent plate is a matte surface. (11) The transmission screen according to claim (7), wherein an anti-reflection film is applied to the exit surface of the light-transmitting plate. (12) A projection type image display device using the transmission screen according to claim (7).