Imaging screen and coating therefor for rear-projection television

Claim 2

An improved rear-projection screen for presenting an image to a viewer, comprising: a lenticulated transparent substrate having a viewable front surface; a dual-purpose single layer coating disposed upon said front surface of said substrate and comprising image-transmitting areas and intervening light-absorbing areas, said coating having dispersed therein, in a common binder, light-scattering elements and photographically formed light-absorbing elements, said photographically formed elements serving to establish said light-absorbing areas, said coating area devoid of said photographically formed elements establishing said image-transmitting areas, said light-scattering elements included in said image-transmitting areas providing for diffusion of an image transmitted therethrough, said light-scattering elements included in said light-absorbing areas being effective to scatter light falling on said front surface of said substrate thereby enhancing the contrast of an image displayed upon said front surface.

Claim 3

The improved screen according to claim 1 in which said image-transmitting areas and said intervening light-absorbing areas are formed by a photographically exposed coating of a positive-working photosensitive material.

Claim 4

The improved screen according to claim 1 in which said image-transmitting areas and said intervening light-absorbing areas are formed by a photographically exposed coating of a positive-working silver-halide emulsion.

Claim 5

The improved screen according to claim 1 in which said image-transmitting areas and said intervening light-absorbing areas are formed by a photographically exposed coating of an autopositive silver emulsion.

Claim 6

The improved screen according to claim 1 in which said light-scattering elements comprise a colloidal suspension of silica particles.

Claim 7

The improved screen according to claim 2 in which said photographically exposed coating includes diazonium salts and couplers.

Claim 8

For use in the manufacture of a rear-projection viewing screen for a projection television system, said screen being of the type having image-transmissive areas and intervening light-absorbing areas on the viewed front surface of a lenticulated transparent substrate, an improved process for applying a single, dual-purpose layer to said viewed surface that provides both diffusion in said image-transmissive areas and image-contrast enhancement, the process comprising: mixing in solution a common binder system having a volatile ingredient, and positive-working, photosensitive elements; uniformly dispersing in said solution light-scattering elements; uniformly coating said viewed surface with said solution and evaporating said volatile ingredient of said common binder system to form a single, dual-purpose layer; exposing said viewed surface to a light source effective to selectively expose said photosensitive elements to define said image-transmissive areas; processing said photosensitive elements to render clear said image-transmissive areas and to create light-absorbing elements in non-exposed areas; such that in a single, dual-purpose coating, said light-scattering elements in said image-transmissive areas provide image diffusion, and said light-scattering elements in said light-absorbing areas provide for scattering light falling on said viewed surface, thereby improving contrast of pictures viewed on said screen.

Claim 9

For use in the manufacture of a rear-projection viewing screen for a projection television system, said screen being of the type having image-transmissive areas and intervening light-absorbing areas on the viewed front surface of a lenticulated transparent substrate, an improved process for applying a single, dual-purpose layer to said viewed surface that provides both diffusion in said image-transmissive areas and image-contrast enhancement, the process comprising: mixing in solution a common binder system having a volatile ingredient, and positive-working, photosensitive elements; uniformly dispersing in said solution light-scattering elements; uniformly coating said viewed surface with said solution and evaporating said volatile ingredient of said common binder system to form a single, dual-purpose layer; exposing said viewed surface to a light source effective to selectively expose said photosensitive elements to define said image-transmissive areas; processing said photosensitive elements to render clear said image-transmissive areas and to create light-absorbing elements in non-exposed areas; such that in a single, dual-purpose coating, said light-scattering elements in said image-transmissive areas provide image diffusion, and said light-scattering elements in said light-absorbing areas provide for scattering light falling on said viewed surface, thereby improving contrast of pictures viewed on said screen.

Claim 10

For use in the manufacture of a rear-projection viewing screen for a projection television system, said screen being of the type having image-transmissive areas and intervening light-absorbing areas on the viewed front surface of a lenticulated transparent substrate, an improved process for applying a single, dual-purpose layer to said viewed surface that provides both diffusion in said image-transmissive areas and image-contrast enhancement, the process comprising: mixing in solution a common binder system having a volatile ingredient, and positive-working, photosensitive elements comprising diazonium salts sensitive to ultra-violet light and suitable couplers therefor; uniformly dispersing in said solution light-scattering elements consisting of colloidal silica particles; uniformly coating said viewed surface with said solution and evaporating said volatile ingredient of said binder system to form a single, dual-purpose layer; selectively exposing said viewed surface to ultra-violet light effective to decompose and render inactive as dye-formers said diazonium salts present to define said image-transmissive areas; introducing said exposed surface to an alkaline atmosphere for coupling the undestroyed diazonium salts with said coupling agents thus forming strongly colored diazonium dyes in said light-absorbing areas; such that in a single, dual-purpose coating, said light-scattering elements in said image-transmissive areas provide image diffusion, and said elements in said light-absorbing areas provide for scattering light falling on said viewed surface thereby improving contrast of pictures viewed on said screen.

Claim 11

For use in the manufacture of a rear-projection viewing screen for a projection television system, said screen being of the type having image-transmissive areas and intervening light-absorbing areas on the viewed front surface of a lenticulated transparent substrate, an improved process for applying a single, dual-purpose layer to said viewed surface that provides both diffusion in said image-transmissive areas and image-contrast enhancement, the process comprising: mixing in solution a common binder system having a volatile ingredient, and positive-working, photosensitive elements comprising diazonium salts sensitive to ultra-violet light and suitable couplers therefor; uniformly dispersing in said solution light-scattering elements consisting of colloidal silica particles; uniformly coating said viewed surface with said solution and evaporating said volatile ingredient of said binder system to form a single, dual-purpose layer; selectively exposing said viewed surface to ultra-violet light effective to decompose and render inactive as dye-formers said diazonium salts present to define said image-transmissive areas; introducing said exposed surface to an alkaline atmosphere for coupling the undestroyed diazonium salts with said coupling agents thus forming strongly colored diazonium dyes in said light-absorbing areas; such that in a single, dual-purpose coating, said light-scattering elements in said image-transmissive areas provide image diffusion, and said elements in said light-absorbing areas provide for scattering light falling on said viewed surface thereby improving contrast of pictures viewed on said screen.