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:
May. 25, 2004
Filed:
Jun. 07, 2001
Thomas M Marshall, Haratsdale, NY (US);
Michael D Pashley, Cortlandt Manor, NY (US);
Frank J P Schuurmans, Valkenswaard, NL;
Koninklijke Philips Electronics N.V., Eindhoven, NL;
Abstract
White light emitting LED luminaire incorporates an array of red, green and blue emitting LEDs and a feedback arrangement to maintain a desired color balance. The feedback arrangement includes photodiodes positioned and enabled to separately measure the light output of each RGB color component. In one embodiment, a single photodiode or array of photodiodes is positioned to intercept reflected light from a partially reflecting element placed in the path of the combined output of the LED array. Individual colors are measured sequentially by pulsing the LEDs and photodiodes or by the use of color filters. In an alternate embodiment, each LED has an associated photodiode, either incorporated into the LED package or in a separate package.