METHOD OF ELECTROPHOTOGRAPHICALLY MANUFACTURING A LUMINESCENT SCREEN FOR A COLOR CRT HAVING A CONDUCTIVE CONTACT PATH

摘要

RCA 86,064 The method of electrophotographically manufacturing a luminescent screen on a substrate of a color CRT includes the steps of forming a photoreceptor by sequentially coating the substrate to form a conductive layer and an overcoating of a photoconductive layer, establishing an electrostatic charge on the photoconductive layer, and exposing selected areas of the photoconductive layer to visible light to affect the charge thereon. Then, the photoconductive layer is developed by the application of suitable triboelectrically-charged, dry-powdered screen structure materials. At least one wear-resistant, conductive contact patch is provided on a peripheral portion of a surface of the substrate. The contact patch has a first portion which underlies at least one of the layers of the photoreceptor and is in electrical contact with the conductive layer, and a second portion which extends from the photoreceptor. The contact patch is utilized during the manufacturing process to electrically ground the conductive layer during charging of the photoconductive layer. The contact patch also is utilized to measure the charge on the photoconductive layer during the developing process. Additionally, the contact patch provides an electrical contact, in the finished tube, between an aluminized layer on the screen and at least one support for a shadow mask.