Abstract: A rear projection screen which includes a front lenticular surface, a diffusion region behind the lenticular surface, a non-diffusion region behind the diffusion region, and a rear phase grating surface, when used with high magnification projection systems, exhibits reduced speckle when compared to other rear projection screen without such a grating.

Abstract: A rear projection screen (1) comprising a lenticular structure (5) and a Fresnel structure (4). The Fresnel structure (4) has riser edges (9) and Fresnel facets (7). The Fresnel facets (7) are divided into two parts. The first part (11) encloses an angle .psi. with the plane of the projection screen. The second part (13) is substantially parallel to the plane of the screen. The Fresnel structure (4) and the lenticular structure (5) are fixed to each other at the second parts of the Fresnel structure.

Abstract: A rear projection screen which includes a front lenticular surface, a diffusion region behind the lenticular surface, a non-diffusion region behind the diffusion region, and a rear phase grating surface, when used with high magnification projection systems, exhibits reduced speckle when compared to other rear projection screen without such a grating.

Abstract: A single plate (3) is provided with a first lens structure (7) of longitudinal lenses (9) on one side. A pattern of strips (15) of a light-absorbing material is provided on the other side. The strips (15) extend parallel to the longitudinal lenses (9) in the horizontal direction when the screen is in use. The screen includes a second lens structure (19) and a diffuser on the side with the strip pattern. This vertical lens structure (19) ensures the spread of light in the horizontal direction, while the diffuser ensures the spread of light in the vertical and horizontal directions. The lenses (21) of the second lens structure (19) have a very much larger power than those of the first, horizontal lens structure (7).

Abstract: A rear projection screen is described, which comprises an optically transparent plate, a first surface of which is provided with a structure of juxtaposed cylindrical lenses which extend in a first direction and a second, opposite surface intended to be directed towards an audience space is provided with strips of a light-absorbing material. These strips also extend in the first direction. On the second surface the plate comprises diffusing means which are formed by a single element by means of a hologram, which element diffuses the light simultaneously in the first direction at a first angle and in a second direction, perpendicular to the first direction, at a second angle, the first and the second angle being different from each other.

Abstract: A rear projection screen which includes a front lenticular surface, a diffusion region behind the lenticular surface, a non-diffusion region behind the diffusion region, and a rear phase grating surface, when used with high magnification projection systems, exhibits reduced speckle when compared to other rear projection screen without such a grating.

Abstract: In a rear projection screen having a large horizontal viewing angle caused by the shape of the first light-spreading elements (51) provided at the front side of the plate (50) the color shift is corrected by providing second light-spreading elements (61) at the rear side of the plate. The second light-spreading elements are aligned approximately parallel to the first light-spreading elements and have a pitch (p) which is considerably smaller than the pitch of the first light-spreading elements. This screen provides a good color correction while the first and the second light-spreading elements are formed in such a way that the screen can be manufactured on an industrial scale without any problem.

Abstract: A front projection screen comprises a transparent plate, the front and rear sides of which have linear Fresnel structures crossing each other and whose rear side is reflective. The riser facets, termed edges, of at least the rear Fresnel lens structure, are substantially perpendicular to the plane of the plate. Ambient light incident on the screen leaves the screen on the rear side via the edges on the rear side or are absorbed by light absorbing material on the edges. This results in an enhancement of the contrast in the observed picture. Further measures enhancing the contrast are the provision of wedge-shaped indentations in the rear side of the plate.

Abstract: The vertical viewing angle of a rear projection screen having a large horizontal viewing angle and good color correction due to the special shape of the light dispersing elements provided on the front side of the plate is increased by elements provided on the rear side and extending in a direction perpendicular to the front side elements. The latter are preferably total internal reflection elements, while the former are not. A bulk diffusor may be largely or completely dispensed with.

Abstract: A rear-projection system by means of which a high brightness and contrast can be obtained in that the projection screen has a maximum transmission for signal light and ambient light. This is achieved by making the surfaces of the projection-screen anti-reflecting as far as possible. A satisfactory contrast is further guaranteed by ensuring that ambient light which has traversed the screen is absorbed in dark layers inside the enclosure. Further steps may be taken in order to prevent ambient light which is incident on the mirror from being reflected back to the screen.

Abstract: The invention relates to a transmission projection screen having a high light output and a suitable contrast, for example for use in a projection television system, and a method of manufacturing such a screen.The projection screen comprises a transparent substrate having a front surface which is provided with mutually parallel ribs 2. At the bottom of the grooves 4 between the ribs 2 two individual layers of light-absorbing particles 11 and 12 are provided. The said particles are fixed by means of an adhesive layer 14.