Abstract The faceplate section of a tricolor cathode-ray tube of the shadow mask type is coated with a photosensitive layer and is exposed through the shadow mask from positions of the light source that represent two of the three colors. For example, in screening the green phosphor, the exposure is made with the light source positioned to simulate the red and the blue electron guns. The exposure interval is extended so that the unexposed elemental areas of the screen, the areas to receive the green phosphor, are made smaller in size than the apertures of the shadow mask, this control of size taking advantage of the penumbra effect. Thereafter, the unexposed elemental areas of the screen are developed in green phosphor. In similar fashion, the screen is coated with red and blue phosphor materials.
The method of screening in accordance with claim 1 in which the material of said layer is light sensitive and its solubility in a predetermined solvent is a function of its exposure to actinic energy; and in which said latent image is developed by treating said screen with said solvent subsequent to said exposure.
Claim 2
Dependent Claim
109 words
The method of screening in accordance with claim 2 in which said color selection electrode is a shadow mask, in which said transparent portions thereof comprise a field of circular apertures, and in which said step of exposing said screen through the apertures of said mask causes elemental portions of said layer which are circular in configuration and individually larger in diameter than the individual apertures of said electrode, to experience a change in solubility in said solvent and causes the size of the elemental portions of said layer that do not experience a change in solubility to be smaller than the size of the apertures in said mask.
Claim 3
Dependent Claim
81 words
The method of screening in accordance with claim 1 in which the material of said layer is photoconductive; which includes the step of uniformly charging said photoconductive layer; and in which the step of exposing said screen discharges said photoconductive layer except the portions thereof that cover said third set of elemental areas assigned to said particular phosphor material; and in which said image is developed by applying a toner, having said particular phosphor as an ingredient, to said photoconductive layer.
Claim 4
Dependent Claim
27 words
The method of screening in accordance with claim 1 in which said two sets of elemental areas are exposed, seriatim, by their respective sources of actinic energy.
Claim 5
Dependent Claim
64 words
The method of screening in accordance with claim 1 in which the material of said layer is light sensitive, includes said third phosphor material as an ingredient, and is rendered soluble in a particular solvent in response to exposure to actinic energy; and in which said latent image is developed by washing said screen in said solvent subsequent to its exposure to actinic energy.