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:
Oct. 07, 2008
Filed:
Dec. 12, 2003
Michel J. Zwanenburg, Northville, MI (US);
James M. Gaines, Mohegan Lake, NY (US);
Michel J. Zwanenburg, Northville, MI (US);
James M. Gaines, Mohegan Lake, NY (US);
Koninklijke Philips Electronics N.V., Eindhoven, NL;
Abstract
An apparatus is directed to controlling a light source. The apparatus provides at least one light source that emits a light signal at a discrete frequency and a reference signal at the discrete frequency. The apparatus further includes a photodetector optically coupled to the light source and designed to receive the light signal. The apparatus additionally includes at least one lock-in system coupled to the photodetector and each light source that receives the light signal from the photodetector and receives the reference signal from the light source. Each lock-in system produces an intensity value of the light source based on the light signal and the reference signal. The lock-in system may include a frequency multiplier and a filter coupled to the frequency multiplier wherein the intensity value is the product of the light signal and the reference signal processed through the frequency multiplier, and filtered to remove non-dc portions.