JP2500282B2 - Rear screen for projector - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rear screen for a video projector, and more particularly, it is suitable for projecting a very large image on a screen by a liquid crystal projector or the like and observing it from the back side of the screen. A rear screen for a projector.

[0002]

2. Description of the Related Art Recently, among various projectors, a liquid crystal projector for projecting an image on a liquid crystal plate onto a screen with a lens has been put into practical use. On the other hand, the screen has a large structure different from that of the projector. Are being developed. FIG. 2 shows an example of such a conventional rear type screen,
Here, 1 is a Fresnel lens sheet, and 2 is a lenticular lens sheet with a black stripe. That is, a Fresnel lens sheet 1 for refracting light toward the front side of the screen is provided on the projector side (not shown), and a vertical black surface is provided on the surface for higher brightness and further improvement of contrast. Rear screen 3 with lenticular lens sheets 2 with stripes arranged side by side
Is formed.

Therefore, in the rear screen 3 thus constructed, the light projected from the projector as shown by the arrow P is passed through the Fresnel lens sheet 1 to the outside of the lenticular lens sheet 2 with the black stripe. An image appropriately diffused on the surface and having a stereoscopic effect is observed by the observer from a direction indicated by an arrow L.

[0004]

By the way, in the rear screen for a video projector as described above, the rear side of the rear screen 3 of the rear screen 3, that is, the rear side of the rear screen when viewed from the observer is observed. It is necessary to shield the surroundings and keep it in a dark room, otherwise, the external light 4 incident on the rear screen 3 from the rear side extremely reduces the image contrast on the rear screen 3 and deteriorates the image quality. It will not be.

In particular, when an extremely large rear type projector device including the rear screen 3 is required, the rear screen 3 itself becomes large, and accordingly, the space on the projector side of the rear screen 3 is surrounded by a dark room. In order to do so, a large wall and a housing are required, which causes a problem that the cost is too high.

It is an object of the present invention to pay attention to such a conventional problem, and in order to solve the problem, the contrast of the image which is seen through the rear screen is lowered without making the space on the projector side a dark room. An object of the present invention is to provide a rear screen for a video projector capable of suppressing the above.

[0007]

In order to achieve such an object, the present invention transmits only the polarized light component of the image light composed of the unidirectional polarized light component projected from the projector and transmits the natural light directly. A polarizing plate capable of blocking the polarized light component, a Fresnel lens that transmits the light component that has passed through the polarizing plate, and a lenticular lens that transmits the light component that has passed through the Fresnel lens, in order from the projector side. The feature is that they are arranged in parallel.

[0008]

According to the present invention, since the polarized light component of the natural light which is orthogonal to the natural light is absorbed by the polarizing plate, it is not necessary to make the projection space from the projector to the rear screen a dark room in order to block external natural light. Moreover, the contrast of the image can be protected.

[0009]

Embodiments of the present invention will be described in detail and specifically below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. here,
10 is a schematic view of a rear screen according to the present invention, and 11 is a means for projecting an image toward the rear screen 10, for example, a liquid crystal projector. That is,
In the rear screen 10 according to the present invention, a polarizer (hereinafter referred to as a polarizing plate) 12 is provided on the liquid crystal projector 11 side of the conventional multi-layer type.

The polarizing plate 12 transmits only the polarized light component contained in the image projection light 13 projected from the projector 11 and blocks the orthogonal polarized light component contained in the external natural light (external light) 4. Is a kind of characteristic polarization filter that
Even if the external light 4 is not blocked by surrounding the space on the liquid crystal projector 11 side by providing such a film-like polarizing plate 12, most of the polarized light component of the external light 4 is absorbed by the polarizing plate 12. be able to. Thus, the contrast of an image obtained through the rear screen 10 according to the present invention is not significantly reduced by the extraneous light 4, which contributes to the cost reduction of the projector apparatus as a whole and expands its application. Can be achieved.

[0012]

As described above, according to the present invention, only the polarized light component of the image light composed of the polarized light component in one direction projected from the projector is transmitted, and the polarized light orthogonal to the natural light is transmitted. A polarizing plate capable of blocking the components, a Fresnel lens transmitting the light component transmitted through the polarizing plate, and a lenticular lens transmitting the light component transmitted through the Fresnel lens are sequentially arranged in parallel from the projector side. Therefore, the orthogonal polarized light component of the external light is provided on the projector side of the rear screen and is absorbed by the polarizing plate that functions as a polarization filter, so it is not necessary to enclose the space on the projector side of the rear screen to form a dark room. Does not significantly reduce the image contrast, which not only contributes to the cost reduction of a large rear projector device, but also reduces the size. Both can be expanded using region of the device.

[Brief description of drawings]

FIG. 1 is an explanatory diagram schematically showing an example of the configuration of the present invention.

FIG. 2 is a perspective view showing a configuration example of a conventional rear screen.

[Explanation of symbols]

 1 Fresnel lens (sheet) 2 Lenticular lens (sheet) 10 Rear screen 11 (Liquid crystal) projector 12 Polarizing plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Atsushi Kato 4-15-3 Nishishinjuku, Shinjuku-ku, Tokyo Sanseido Shinjuku Building, 4th floor, Advanced Imaging Technology Research Center (72) Inventor Masahiko Nishihara Nishishinjuku, Shinjuku-ku, Tokyo 4-15-3 Sanseido Shinjuku Building, 4th Floor, Advanced Video Technology Research Laboratory (56) References JP-A-4-73637 (JP, A)

Claims (2)

(57) [Claims] 1. A polarizing plate capable of transmitting only the polarized light component of image light composed of a polarized light component in one direction projected from a projector and blocking the orthogonal polarized light component of natural light, and the polarizing plate. A rear screen for a projector, wherein a Fresnel lens that transmits the transmitted light component and a lenticular lens that transmits the light component transmitted through the Fresnel lens are sequentially arranged in parallel from the projector side. 2. The rear screen for a projector according to claim 1, wherein the projector is a liquid crystal projection type projector.