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. 31, 2017
Filed:
Aug. 16, 2013
Parthiban Santhanam, Cambridge, MA (US);
Dodd Joseph Gray, San Francisco, CA (US);
Rajeev Jagga Ram, Arlington, MA (US);
Parthiban Santhanam, Cambridge, MA (US);
Dodd Joseph Gray, San Francisco, CA (US);
Rajeev Jagga Ram, Arlington, MA (US);
Massachusetts Institute of Technology, Cambridge, MA (US);
Abstract
Contrary to conventional wisdom, which holds that light-emitting diodes (LEDs) should be cooled to increase efficiency, the LEDs disclosed herein are heated to increase efficiency. Heating an LED operating at low forward bias voltage can be accomplished by injecting phonons generated by non-radiative recombination back into the LED's semiconductor lattice. This raises the temperature of the LED's active rejection, resulting in thermally assisted injection of holes and carriers into the LED's active region. This phonon recycling or thermo-electric pumping process can be promoted by heating the LED with an external source (e.g., exhaust gases or waste heat from other electrical components). It can also be achieved via internal heat generation, e.g., by thermally insulating the LED's diode structure to prevent (rather than promote) heat dissipation. In other words, trapping heat generated by the LED within the LED increases LED efficiency under certain bias conditions.