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:
Mar. 24, 1992
Filed:
Aug. 20, 1990
Erich Bozzer, Dearborn Heights, MI (US);
James M Raffa, Rochester, MI (US);
Thomas G Burke, Royal Oak, MI (US);
Ford Motor Company, Dearborn, MI (US);
Abstract
A method and system for providing a wide range of variable brightness levels for a vacuum fluorescent (VF) display by changing the duty cycle of the driving signal beyond the limits of normal driving techniques by varying the frequency as well as the on-time of the driving signal. The driving signal is multiplexed by a programmed driver microcomputer to drive a plurality of grids. Consequently, by varying the frequency, the multiplex period is also varied. The driver microcomputer communicates with a host microcomputer as well as drivers and grids of the VF display to control the VF display. In addition, the driver microcomputer samples a VF filament signal to synchronize the VF display multiplex frequency with the frequency of the VF filament signal to reduce flicker at low display brightness levels. The method and system achieve a continuously variable appearance of the VF display from full bright to barely discernable.