Abstract: In accordance with the present invention, an apparatus for developing a latent image formed on a photoreceptor, which is deposited on an interior surface of an output window of a display device, is disclosed. The developing apparatus includes a developing chamber, having a support surface for supporting the output window, a screen structure material reservoir for storing, deagglomerating and feeding the screen structure material, and a triboelectric gun assembly communicating with the reservoir. The gun assembly triboelectric charges and imparts a desired charge polarity to the screen structure material. The gun assembly further includes at least one material dispersing nozzle spaced from the support surface for distributing the charged material for deposition onto the latent image.

Abstract: In accordance with the present invention, a method of electro-photographically manufacturing a luminescent screen assembly for a color CRT 10 on an interior surface of a faceplate panel 12 is described. A volatilizable, organic conductive (OC) layer 32 is provided on the interior surface of the panel and a volatilizable, organic photoconductive (OPC) layer 34 overlies the OC layer. The method includes the steps of: establishing a substantially uniform electrostatic charge on the OPC layer; exposing selected areas of the OPC layer to visible light to affect the charge thereon; developing the selected areas of the OPC layer with a triboelectrically charged dry-powdered, screen structure materials; fixing the screen structure materials to the underlying OPC layer with a suitable fixative; filming the screen structure materials; aluminizing the screen; and baking the aluminized screen.

Abstract: A luminescent screen assembly for a CRT is made by first coating the interior surface of a faceplate panel with a photoconductive layer which overlies a conductive layer. A multiplicity of red-, green- and blue-emitting phosphor screen elements are then deposited in color groups, in a cyclic order, onto the interior surface of the panel. A negative charge is then established on the photoconductive layer. The charge is weakened in the areas where the photoconductive layer underlies the phosphor screen elements, but unaffected in the open areas separating the phosphor screen elements. The charged, open areas of the photoconductive layer are discharged by flood illumination and reversal developed by depositing thereon particles of light-absorptive matrix material having a triboelectric charge of the same polarity as the charge established on the photoconductive layer. The novel process provides a high opacity matrix.

Abstract: A method and apparatus for exposing a layer of photoresist on a sheet includes positioning the sheet in a vacuum printing frame comprising a glass photographic printing plate carrying an opaque master pattern of metal or metal oxide on a central area of the printing plate. A light transmissive rubbery material is patterned in such a fashion as to overlie the opaque portions of the master pattern and provide a continuous path between the islands overlying the opaque master pattern. The rubbery material also extends in the peripheral area of the photographic printing plate and a plurality of mesas separated by channels are formed in this peripheral area. The channels have a width substantially greater than the path width formed between adjacent islands of rubbery material overlying the opaque portions of the pattern. The peripheral channels facilitate the evacuation of the plate and reduce evacuation time.

Abstract: A method for exposing a layer of photoresist on a sheet includes positioning the sheet in a vacuum printing frame comprising a glass plate carrying an opaque master pattern of metal or metal oxide. With the pattern opposite the coating, the frame is evacuated and the layer is exposed. The pattern has a substantially-uniform thickness in the range of about 0.5.+-.0.2 micrometer. To reduce the times for evacuating and devacuating the frame, the pattern side of the glass plate carries an array of light-transparent islands up to about 3.0-micrometer thick. An overcoating of wax on the islands is a further aid.

Abstract: A method for exposing a layer of photoresist on a sheet includes positioning the sheet in a vacuum printing frame comprising a glass plate carrying an opaque master pattern of metal or metal oxide. With the pattern opposite the coating, the frame is evacuated and the layer is exposed. The pattern has a substantially-uniform thickness in the range of about 0.5.+-.0.2 micrometer. To reduce the times for evacuating and devacuating the frame, the pattern side of the glass plate carries an array of light-transparent islands up to about 3.0-micrometer thick. An overcoating of wax on the islands is a further aid.

Abstract: A method for etching an array of apertures through a carbon-steel sheet wherein, for each of the majority of said apertures, the ratio of the desired smallest cross-sectional dimension thereof to the thickness of said sheet is less than about 0.9, said sheet having etch-resistant stencils on opposite major surfaces thereof, said method comprising contacting said stencilled major surfaces with ferric chloride etchant having a specific gravity in a range at which a smooth finish is realized.

Abstract: A method for exposing a layer of photoresist on a sheet includes positioning the sheet in a vacuum printing frame comprising a glass plate carrying an opaque master pattern of metal or metal oxide. With the pattern opposite the coating, the frame is evacuated and the layer is exposed. The pattern has a substantially-uniform thickness in the range of about 0.5.+-.0.2 micrometer. To reduce the times for evacuating and devacuating the frame, the pattern side of the glass plate carries an array of light-transparent islands up to about 3.0-micrometer thick. An overcoating of wax on the islands is a further aid.

Abstract: A method for etching a strip of iron-nickel alloy, such as invar steel, having etch-resistant stencils on opposite major surfaces thereof includes contacting the stencilled surfaces with a ferric-chloride etchant. The etchant is controlled (a) to contain not more than 5 molar percent nickel ion with respect to the total content of nickel and iron ions, (b) to have a specific gravity greater than about 1.495 (48.degree. Baume) (c) and to have a temperature greater than 70.degree. C.

Abstract: The surfaces of a ferrous metal body are coated with a heat-fusible, chemically-oxidizing composition, such as sodium nitrate or potassium nitrate. Then, the coated body is heated above the melting temperature of the coating, preferably above 350.degree. C., until the coating melts, spreads over the surfaces, reacts with the material of the surfaces and produces a black oxide coating thereon.

Abstract: When precision etching a succession of articles from a strip of metal having random variations in thickness and moving along a prescribed path, the thickness of the metal strip is monitored, and the etching step is adjusted in response to the monitored thickness to compensate for the thickness variations.