JPS5879239A - Transmission type screen - Google Patents

Abstract

PURPOSE:To improve the brightness of pictures markely and to prevent the reflection of unnecessary light from a front surface in a rear projection type image receiver by forming Fresnel lenses on the rear side of a screen body and forming many conical bodies on the front side. CONSTITUTION:Projecting lighg 7 for projection of pictures irradiated from the rear of a screen body 8 is bent in the direction parallel with the axis of the screen by Fresnel lenses 9, and is emitted to the front side by having directivity around the axial direction of the screen by conical bodies 10. Therefore the emission of the projecting light toward the directions of large angles from the axis on the front side of the body 8 is decreased and the brightness of the picture is increased markedly. If the conical bodies 10 having semispherical tips and light absorptive materials 11 among the clearances between the bodies 10 are provided, the reflection of the unncessary incident light from the front side is prevented and the easy-to-see pictures are projected.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a configuration of a transmissive screen that can be used in a rear projection television receiver, etc., and is capable of projecting a uniformly bright image when viewed from the front. It seeks to provide something.

A transmissive screen is used to diffuse the light of an image projected from the rear to the front so that it can be viewed from the front. Used in readers, etc.

An example of such a projection television receiver will be explained with reference to FIG. The light rays of the television image thus obtained are projected onto the screen 2 from the rear via the lens system 4 and the reflecting mirror 6.

As a transparent screen 2 for such uses,
Traditionally, a transparent resin plate such as acrylic resin or styrene resin has been uniformly mixed with a light-diffusing material, which scatters the light of the projected television image and makes it visible. What has already been done is used.

However, with conventional transmissive screens, the light scattered by light-scattering substances in the screen body is scattered in a wide direction in front of the screen, resulting in a lot of wasted light and insufficient brightness of the image. Moreover, the light coming from the front direction is reflected and enters the viewer's eyes, making it difficult to see the image.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a transmission type screen which eliminates such conventional drawbacks.

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 2 and 3. In this transmissive screen, a transmissive screen main body 8, onto which projection light 7 for projecting images such as television images is irradiated from the back side, is made of a translucent resin such as acrylic resin or styrene resin. A feature is that a Fresnel lens 9 centered at the center of the screen is integrally formed on the back side, and a large number of small diameter cones 10 are integrally formed over the entire surface on the front side. The shape of the cone 10 is optimally conical, and its tip is preferably shaped into a smooth hemisphere. With this configuration, the projection light 7 projected from the back side
is bent by the Fresnel lens 9 in a direction parallel to the axis of the screen, and further directed toward the front side by the cone 10 with directionality centered on the axis of the screen. Therefore, the projected light is less likely to be emitted in a direction at a large angle from the axis on the front side of the screen main body 8, making the brightness of the image seen from the front side much brighter than before. be able to. Moreover, by providing the cone 1o in this way, 1. There is almost no possibility that light from illumination or the like coming from the front side will be reflected and enter the viewer's eyes, and there is no fear that the contrast of the image will be impaired or that it will become difficult to see.

However, by providing a light-absorbing substance 11 such as black paint in the gaps between these cones 1o, unnecessary reflection of incident light can be more effectively prevented.

As described above, according to the transmission type screen of the present invention, a Fresnel lens is formed on the back side of the screen body and a large number of cones are formed on the front side, so that the projected light from the back side is directed toward the front axis. 5. The brightness of the image when viewed from the front can be greatly improved by concentrating the light in one direction, and it also prevents unnecessary light reflection from the front, making it easier to see. It is capable of displaying images.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of an example of a projection type television receiver using a transmissive screen, Fig. 2 is a cross-sectional view of a portion of the transmissive screen in an embodiment of the invention, and Fig. 3 is a front view thereof. . 8...Screen body, 9...Fresnel lens, 10...Cone, 11...Light-absorbing substance. Figure 1

Claims (2)

[Claims] (1) A transmissive screen body is provided which is irradiated with projection light for image projection from the back side, a Fresnel lens is formed on the back side of the screen body, and a large number of cones are formed on the front side. Features a transparent screen. (2) A transmission type screen according to claim 1, characterized in that a light-absorbing substance is interposed between the plurality of cones.