Method of forming a black patterned portion on a phosphor screen of a cathode-ray tube for color television sets

Claim 1

A method of forming a black patterned portion on a phosphor screen of a cathode-ray tube for color television sets as defined in claim 1 wherein said step of depositing said first and second materials comprises the steps of piling said two materials in a stack of successive layers in a crucible, and heating in a vacuum and vaporizing said stack for first depositing said black material of lower melting point on the inner surface of the face plate, then depositing a mixture of said two materials on said black material layer, said mixture having a mixture composition ratio gradient, and finally depositing said material of high melting point on said layer of said mixture of said two materials.

Claim 3

A method of forming a black patterned portion on a phosphor screen of a cathode-ray tube for color television sets comprising the steps of applying on the inner surface of a face plate of a panel section of the cathode-ray tube a coat of material which can readily be removed with a removing agent in a subsequent step, coating said coat of readily removable material with a layer of photOsensitive material, mounting a shadow-mask on the panel section, exposing said photosensitive material layer to a light source through apertures of the shadow-mask by a photo printing process, removing said shadow-mask from said panel section, subjecting the photosensitive material layer to a developing treatment to remove the photosensitive material from unexposed portions of the photosensitive material layer, applying a removing agent for removing said readily removable material which is exposed after the photosensitive material layer is removed therefrom, depositing a black patterned portion forming composition comprising a material of small atomic number and high melting point and a black material of lower melting point on the inner surface of the face plate of the panel section by simultaneously vaporizing said two materials, and removing the remainder of said readily removable material from the inner surface of the face plate of the panel section with a removing agent.

Claim 5

A method of forming a black patterned portion on a phosphor screen of a cathode-ray tube for color television sets comprising the steps of applying on the inner surface of a face plate of a panel section of the cathode-ray tube a coat of paint comprising a pigment such as zinc oxide dissolved in a solvent such as a phenol resin dissolved in butyl alcohol, coating said coat of paint on said panel section with a layer of photosensitive material, mounting a shadow-mask on the panel section, exposing said photosensitive material layer to a light source through apertures of the shadow-mask by a photo printing process, removing said shadow-mask from said panel section, subjecting the photosensitive material layer to a developing treatment to remove the photosensitive material from an unexposed portion of the photosensitive material layer, applying a water solution of sodium hydroxide for removing the paint from the portion of said paint coat which is exposed after the photosensitive layer is removed therefrom, depositing a black pattern forming composition comprising boron carbide and chromium on the inner surface of the face plate of the panel section by simultaneously vaporizing said two materials, and applying a water solution of sodium hydroxide for removing the remainder of said paint from the inner surface of the face plate of the panel section.

Claim 7

A method of forming a black patterned portion on a Phosphor screen of a cathode-ray tube for color television sets, comprising the following steps: a. applying on the inner surface of a face plate of a panel section of the cathode-ray tube a layer of pigment which can be removed by a first solvent but cannot be removed by a second solvent, b. coating said layer with photosensitive material which is soluble in the second solvent before being exposed to light, but insoluble in the second solvent after having been exposed to light, c. placing an apertured shadow-mask over the coating, d. exposing said coating to a light source shining through the apertures of the shadow-mask, e. removing said shadow-mask, f. treating the coating of photosensitive material with said second solvent to remove the unexposed portions of the photosensitive material and to uncover the portions of the layer corresponding to the unexposed portions of the photosensitive coating, g. treating the uncovered portions of the layer with said first solvent to remove the uncovered portions of the layer and to expose the portions of the face plate corresponding to the uncovered portions of the layer, h. vaporization depositing a composition comprising a material of small atomic number and high melting point and a black material of lower melting point on the uncovered portions of the face plate and the exposed portions of the photosensitive material, and i. treating with said first solvent the portions of the layer which are covered with the exposed portions of the photosensitive material layer to remove the portions of the layer which are covered with the exposed portions of the photosensitive material layer which removes the photosensitive material and the vapor-deposited composition coefficient which cover said portions of the layer whereby the portions of the face plate corresponding to the exposed portions of the photosensitive material layer are uncovered.