Abstract: A transparent rear-projection screen is described where the side facing the projectors has a lens surface for parallelling of the light, and where the front side has vertical upright forerunning lenses to upread the light in a horizontal plane, and where between these lenses there are grooves with a light absorbing material to increase the contrast of the projected picture.

Abstract: A transparent, rear-light projection screen that has lenses on its back side facing the projectors for paralleling light from the projectors. The screen on its front side has upright, forerunning asymmetric cylinder lenses with partially reflecting projections having light-refractive surfaces, facing outwardly from the front side and opposite to the direction from which the paralleled light originates from behind. The projection screen improves the color contrast and increases the projected light when the screen is viewed from a side direction.

Abstract: A transparent rear-light projection screen with V-shaped grooves is described, where the rear side of the screen, i.e. the side turned towards the projector is supplied with outwardly extending, elongate parallel lenses, the focal point of which is congruent with the front plane of the screen which is made up of outwardly extending elongate projections on whose tops the light can emit, and where--between the tops of the projections--there are grooves which are covered with material impenetrable to light, such as black color, for the purpose of increasing the contrast.

Abstract: A transparent rear-projection screen, e.g. for video projection, consisting of three screen elements, of which the rearmost element, which faces the light sources, is a Fresnel lense, and the middle element on its reverse or entrance side is provided with lens profiles for horizontal diffusion of the light, and on its front or exit side are lenses for parallelling the light from various light sources, and in which screen the foremost, visually enhanced screen element has on its reverse or entrance side horizontal, convex, rectilinear lenses, the focal point of which is congruent to the tops of projections provided on the front or exit side of the foremost screen element, and from the surface of which the light is emitted.

Abstract: A rear projection screen consists of a Fresnel lens and a picture-forming screen placed in front of it. The picture-forming screen has vertical backward convex lenses on its back and vertical masking strips on its front and strip-shaped sections situated between the masking strips and opposite the backward convex lenses. Each of these is designed to refract light rays coming from behind so that they are directed towards the strip-shaped sections. In order to increase the picture resolution or definition capability of the screen and to avoid notch sensitivity between the backward convex lenses an intermediate lens is provided between every two of the backward convex lenses.

Abstract: A transparent rear projection screen has a Fresnel lens for paralleling light arriving from behind. In the front surface the screen is provided with grooves which extend in the vertical direction in the position of use of the screen. Each of the side flanks of the grooves adjoins a side part of an adjacent, also vertically extending convex lens. The side flanks of the grooves are totally reflecting to parallelled light arriving from behind in order to increase the deflection in the lateral direction of a part of the light arriving from behind by means of reflection into the adjacent lens. The angle which a side flank forms together with the side part of the adjacent lens is so small that total reflection from the inner surface of the side part of the lense of light which is totally reflected of the side flank in question is avoided. Moreover, between the vertical lenses to which the side flanks adjoin, at least one further lens is arranged.

Abstract: A transparent rear projection screen has a lense system for paralleling light arriving from behind. On the front side of the screen rectilinear lenses extending in the vertical direction in the position of use of the screen are provided the sides of which form a small angle of inclination with respect to the normal to the screen. The sides are totally reflecting to light arriving from behind and between the reflecting lenses further lenses are arranged. In order to compensate for color shading by the projection of differently colored television images upon the rear side of the screen, the tops of the reflecting lenses are so shaped and their totally reflecting sides have such an inclination with respect to the normal to the screen, and moreover have such a width that at the most 80% of the light which from behind enters the reflecting lenses is emitted through the tops of the lenses, and that at least 20% of said entering light is emitted through the sides of the lenses.