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:
Jun. 26, 2001
Filed:
Dec. 31, 1998
Richard Mitchel Meldrum, Glendale, AZ (US);
Bruce Anthony Pitman, Phoenix, AZ (US);
Honeywell International Inc., Morristown, NJ (US);
Abstract
Methods and apparatus for controlling the brightness level of a lamp in a backlit LCD display include primary and secondary controllers. The primary controller establishes the arc drive to the lamp to achieve the desired lamp brightness. The primary controller includes a desired brightness set-point as a first input, and a feedback signal corresponding to actual brightness detected at the lamp as a second input. The primary controller operates in real time, essentially adjusting the lamp arc drive instantaneously as a function of the detected brightness feedback signal. The secondary controller is employed to fine tune the control of the lamp by determining whether the desired brightness level may be achieved more efficiently. The secondary controller varies one or more parameters, such as temperature, within the lamp to achieve the optimum operating point of the lamp at the desired brightness level.