Conventional rear projection screens for use in rear projection display apparatus generally comprise two lens sheets including a Fresnel lens sheet and a horizontal lenticular lens sheet containing a light-diffusing member. However, these rear projection screens invite decreased contrast of the screen because external light from lighting at the ceiling of a room or light reflected from surrounding walls is scattered and reflected at the surface of the screen.
To prevent the reflection of the incident external light and to improve the image contrast, a screen having three sheets including two lenticular lens sheets arranged in a perpendicular direction to each other has been proposed. This type of screens can be found in, for example, Japanese Unexamined Patent Application Publications No 07-5573 and No. 08-101459. In these screens, the ratio of black stripes can be substantially increased and the contrast can be improved by using the lenticular lens sheets arranged in a perpendicular direction to each other.
However, in a screen shown in FIG. 7 including a Fresnel lens sheet, a vertical lenticular lens sheet and a horizontal lenticular lens sheet in this order from a projector side, the incident light is reflected at the surface of the vertical lenticular lens and emerges as stray light toward a viewer, thereby causing image deterioration. In a screen shown in FIG. 8 including a Fresnel lens sheet, a horizontal lenticular lens sheet and a vertical lenticular lens sheet in this order from a projector side, light from a light source positioned above the viewer, such as lighting, is vertically diffused and reflected at fine protrusions and depressions and at the edges of the black stripes on the viewer side of the vertical lenticular lens sheet and appears an image of the light source elongated in a vertical direction, thereby deteriorating the image contrast and decreasing the image quality.
Accordingly, an object of the present invention is to solve the above problems while keeping high contrast performance.
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USPTO Backgrounds