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. 27, 2014
Filed:
Oct. 08, 2008
Michael Datta, Boston, MA (US);
Ihor Lys, Milton, MA (US);
Michael Datta, Boston, MA (US);
Ihor Lys, Milton, MA (US);
Koninklijke Philips N.V., Eindhoven, NL;
Abstract
A lighting apparatus () includes one or more first LEDs () for generating a first spectrum of radiation (), and one or more second LEDs () for generating a second different spectrum radiation (). The first and second LEDs are electrically connected in series between a first node (A) and a second node (B), between which a series current () flows with the application of an operating voltage () across the nodes. A controllable current path () is connected in parallel with one or both of the first and second LEDs so as to at least partially divert the series current, such that a first current () through the first LED(s) and a second current () through the second LED(s) are different. Such current diversion techniques may be employed to compensate for shifts in color or color temperature of generated light during thermal transients, due to different temperature-dependent current-to-flux relationships for different types of LEDs.