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:
Nov. 21, 2000
Filed:
Nov. 25, 1998
David N Crane, Woodland, WA (US);
Pacific Aerospace & Electronics, Inc., Wenatchee, WA (US);
Abstract
A gas discharge lamp controller controls and drives a gas discharge lamp, which may be either a hot cathode lamp or a cold cathode lamp, and may or may not be a fluorescent lamp. The lamp controller separately varies the current and the voltage that are delivered to the lamp to drive it in an illuminated state over a wide range of brightnesses, including very low brightness levels without flicker. The lamp controller includes a brightness control circuit and a driver circuit. A memory circuit stores values for generating arc currents that correspond to a selected brightness and values for generating arc voltages that correspond to the brightness represented by the digital control value. Digital to analog converters convert the arc voltage and arc current values to analog control signals that are delivered to an arc current driver circuit and an arc voltage driver circuit. A photodetector may provide feedback as to the brightness of light generated by the lamp to control different phases of operation (e.g., start-up and normal operation) as well as to monitor the accuracy at which the lamp generates selected light brightnesses.