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1. (WO2017175148) HIGHLY DIRECTIONAL LIGHT SOURCE WITH HIGH EXTRACTION EFFICIENCY AND METHOD TO MANUFACTURING THE SAME

Pub. No.:    WO/2017/175148    International Application No.:    PCT/IB2017/051946
Publication Date: Fri Oct 13 01:59:59 CEST 2017 International Filing Date: Thu Apr 06 01:59:59 CEST 2017
IPC: H01L 33/22
Applicants: NOVAGAN
Inventors: FELTIN, Eric
GALLO, Pascal
Title: HIGHLY DIRECTIONAL LIGHT SOURCE WITH HIGH EXTRACTION EFFICIENCY AND METHOD TO MANUFACTURING THE SAME
Abstract:
The present invention consists in an LED structure with a narrow angular distribution featuring improved extraction efficiency. The device comprises in particular, but not exclusively an angular bandpass filter reducing the emission angular dispersion, as well as a combination of mirror structure and diffusing elements that redirect the light rejected by the filter within the angular passband, thus improving the extraction efficiency within this passband. Simulations and experiments suggest that in the case of an SiO2 cavity sandwiched between two DBR mirrors comprising 4 SiO2/Si3N4 pairs each, having a resonance at 430nm, a Lorentzian emission of the light emitters centered in 430nm with a FWHM of 10nm, the angular dispersion is ±16°, and the extraction efficiency is approximately 70%. Introducing a mismatch of 8nm between the LED emission and the cavity mode, the angular dispersion is ±25°, and the extraction efficiency within this cone is close to 90%.