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.

Date of Patent:
Nov. 14, 1989

Filed:

Nov. 10, 1988
Applicant:
Inventor:

Geoffrey S Hedrick, Malverne, PA (US);

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01J / ; H01J / ;
U.S. Cl.
CPC ...
313450 ; 445-3 ; 445 36 ;
Abstract

An internal electrostatic field-generating, beam-controlling element in a cathode ray tube is formed by depositing an initially continous layer of resistive material on a substrate and applying a voltage differential across the coating to generate a field-generating current therethrough during operation of the tube. After completion of tube assembly and sealing of the tube envelope, the element is custom fine-tuned by projecting an externally-originating laser beam through the envelope wall to selectively remove portions or areas of the resistive material, thereby predeterminately distorting the electrostatic field and selectively changing the effect of the field on the imaging electron beam. This procedure readily enables both correction of perceived deficiencies in and intentional modifications to one or more characteristics of the electron beam.


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