Nakamura S.,University of California at Santa Barbara |
Krames M.R.,Soraa Inc
Proceedings of the IEEE | Year: 2013
The history of development for gallium-nitride-based light-emitting diodes (LEDs) is reviewed. We identify two broad developments in GaN-based LED technology: first, the key breakthroughs that enabled the development of GaN-based devices on foreign substrates like sapphire (first-generation LEDs), and, second, a new wave of devices benefiting from developments in GaN substrate manufacturing, which has led to native bulk-GaN-based LEDs with unprecedented performance characteristics that portend a disruptive shift in LED output power density and the corresponding cost of generating light. © 1963-2012 IEEE.
David A.,Soraa Inc
LEUKOS - Journal of Illuminating Engineering Society of North America | Year: 2014
We study the use of large reflectance sample sets to assess the color fidelity of light sources. We introduce three data sets covering a large fraction of the color space and a method to compute color fidelity over these sets. By applying this calculation to various source spectra, we show that some sources have significantly lower fidelity than would be predicted using the eight samples of the color rendering index. Structured and truncated source spectra are especially prone to this pitfall, whereas broad and smooth spectra are more resilient. Copyright © Illuminating Engineering Society.
David A.,Soraa Inc
IEEE/OSA Journal of Display Technology | Year: 2013
Surface roughening is frequently employed to increase light extraction from light-emitting diodes (LEDs), especially in the important case of III-Nitride LEDs. We explore the physics governing this scheme. We introduce a numerical model, based on solving Maxwell's equations, to accurately describe scattering by a roughened semiconductor interface. This model reveals the complex angular dependence of the scattering properties. We then couple this approach to an LED light extraction model and predict how surface roughness impacts light extraction. We focus on two important cases, thin-film LEDs and volumetric LEDs. We show that optical losses in the LED dictate light extraction, and that volumetric LEDs offer an opportunity for ultimate efficiency. © 2005-2012 IEEE.
Soraa Inc | Date: 2015-01-20
A method for manufacturing a multi-emitter laser diode device includes providing a substrate having a surface region and forming epitaxial material overlying the surface region, the epitaxial material comprising an n-type cladding region, an active region comprising at least one active layer overlying the n-type cladding region, and a p-type cladding region overlying the active layer region. The epitaxial material is patterned to form a plurality of dice, each of the dice corresponding to at least one laser device, characterized by a first pitch between a pair of dice, the first pitch being less than a design width. Each of the plurality of dice are transferred to a carrier wafer such that each pair of dice is configured with a second pitch between each pair of dice, the second pitch being larger than the first pitch.
Soraa Inc | Date: 2015-04-28
LED lamp systems having improved light quality are disclosed. The lamps emit more than 500 lm and more than 2% of the power in the spectral power distribution is emitted within a wavelength range from about 390 nm to about 430 nm.