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:
Oct. 18, 1983
Filed:
Sep. 28, 1981
Christopher R Dusard, Phoenix, AZ (US);
Thomas W Spilsbury, Phoenix, AZ (US);
Sperry Corporation, New York, NY (US);
Abstract
In a patterned screen color cathode ray tube (CRT) display, for example, a shadow-mask type color CRT, particularly for use under a wide range of ambient light conditions, such as an aircraft cockpit, incompatibilities between the screen pattern character, the type of writing (such as stroke and raster), and the display linewidth, may result in stroke written lines which appear as a twisted fiber rope and in raster written areas which appear wavy or watery; that is, a moire appearance. Both of these effects vary in accordance with the required display brightness over the ambient light range due to variations in beam or linewidth with corresponding variations in the required cathode drive voltages. These undesirable roping and moire effects are eliminated or substantially eliminated by varying the electron beam focus in accordance with a computed reference brightness compatible with the range of ambient brightnesses in a manner to maintain a predetermined, substantially fixed beam width for stroke written symbols and effective line spacing for raster written symbols.