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:
Jan. 08, 2008
Filed:
Aug. 26, 2005
Pieter Grootes, Best, NL;
Noboru Kaito, Tilburg, NL;
Robert F. M. Hendriks, Overlangel, NL;
Charles A. Schrama, Penang, MY;
Emanuel Stassar, Sprang Capelle, NL;
Dennis Claessens, Eindhoven, NL;
Pieter Grootes, Best, NL;
Noboru Kaito, Tilburg, NL;
Robert F. M. Hendriks, Overlangel, NL;
Charles A. Schrama, Penang, MY;
Emanuel Stassar, Sprang Capelle, NL;
Dennis Claessens, Eindhoven, NL;
Philips Lumileds Lighting Company, LLC, San Jose, CA (US);
Abstract
An LED backlight structure for setting voltages and currents for LEDs. Red LEDs are connected in series between a first voltage regulator and a first controllable current source, green LEDs are connected in series between a second voltage regulator and a second controllable current source, blue LEDs are connected in series between a third voltage regulator and a third controllable current source. The current sources may be linear current regulators controlled to balance the three colors to achieve a target light output of the board using a light detection chamber. PWM controllers control transistor switches connected in parallel across groups of LEDs, where the duty cycles set the average current through each group of LEDs. The control values used to achieve target light characteristics are stored in memory. The PWM controller may control brightness levels of the LEDs. The backlight may be for an LCD television.