The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 11, 1976
Filed:
Nov. 04, 1974
Howard G Lange, Prospect Heights, IL (US);
Zenith Radio Corporation, Chicago, IL (US);
Abstract
This disclosure depicts a method of forming a pattern of electron-transmissive apertures in a color selection mask for use in a color television cathode ray tube. The method comprises: providing an electrically conductive blank with a substrate layer and an aperture-defining layer; applying a coating of photoresist material on the aperture-defining layer; exposing the photoresist coating in a first preselected illumination pattern with a preselected degree of exposure and in a second preselected illumination pattern with a preselected degree of exposure substantially different from the preselected degree of exposure of the first preselected illumination pattern; developing the exposed photoresist coating corresponding to the first preselected illumination pattern; etching through the blank; developing the exposed areas of the photoresist coating corresponding to the second preselected illumination pattern thereby baring a portion of the aperture-defining layer; and etching the newly bared portion of the aperture-defining layer. Apparatus for use with the above-described method is disclosed.