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:
Sep. 30, 2008
Filed:
Jul. 27, 2005
Johannes Hendrik Wessels, Eindhoven, NL;
Arnold Willem Buji, Eindhoven, NL;
Geert Willem Van Der Veen, Eindhoven, NL;
Johannes Hendrik Wessels, Eindhoven, NL;
Arnold Willem Buji, Eindhoven, NL;
Geert Willem Van Der Veen, Eindhoven, NL;
Koninklijke Philips Electronics N.V., Eindhoven, NL;
Abstract
A fluorescent lamp (), in particular a backlight lamp of a display device, is supplied with an alternating voltage, a frequency and an amplitude of which being greater during ignition than during normal operation of the lamp. The voltage (V) across the lamp and the current (I) through the lamp are measured to provide a measured voltage value and a measured real lamp current value. From the alternating voltage there is derived a voltage (V). The measured voltage value is multiplied by the sum of the measured real lamp current value and the derived voltage. The multiplication result (P=V*(I+V)) is compared with a reference value (Ref), which results in a difference or error value. The error value is used to control the frequency and the amplitude of the alternating voltage (V), such that the error value is minimized.