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Phosphor-Free White Light Source


Technology Benefits

The light-emitting layer in a semiconductor device is deposited on a textured surface.   Allows for higher material quality and improved light extraction efficiency.  Achieves higher-quality UV to infrared light-emitting devices than are currently achievable by conventional methods.


Technology Application

Nitride-based lighting    This technology is available for licensing.


Detailed Technology Description

Researchers at the University of California, Santa Barbara have developed a phosphor-free white light source, where an indium-containing light-emitting layer, as well as subsequent device layers, is deposited on a textured surface. It is possible to develop a device with suitably textured areas that would emit at two or more peak wavelengths, where both peak emission wavelengths are produced primarily from the indium-containing light-emitting layer.


Supplementary Information

Patent Number: US8227820B2
Application Number: US200554271A
Inventor: Sharma, Rajat | Pattison, Paul Morgan | Kaeding, John Francis | Nakamura, Shuji
Priority Date: 9 Feb 2005
Priority Number: US8227820B2
Application Date: 9 Feb 2005
Publication Date: 24 Jul 2012
IPC Current: H01L003300 | H01L003322
US Class: 257095 | 257089 | 257090 | 257103 | 257E33028 | 257E33034 | 438042 | 438047
Assignee Applicant: The Regents of the University of California
Title: Semiconductor light-emitting device
Usefulness: Semiconductor light-emitting device
Summary: For manufacturing semiconductor light-emitting device.
Novelty: Semiconductor light-emitting device manufacture method involves depositing indium containing light-emitting layer and subsequent device layer on textured surface


Industry

Optics


Sub Group

LED/OLED


Application No.

8227820


Others

Background

Typical incandescent light sources, while highly energy-inefficient, have a desirable characteristic broad-emission spectrum and a high color-rendering index. In order to mimic these latter attributes in gallium nitride (GaN) based devices, current state-of-the-art designs have certain disadvantages. The process of down-conversion is inherently inefficient due to the Stokes shift and poor conversion efficiency. The emission spectrum and intensity are highly sensitive to spatial variations in the phosphor composition and thickness, and may vary greatly with emission direction. Finally, while the diode itself may have a long lifetime, phosphors typically degrade with time, resulting in a variation of the emission spectrum with time. Current designs proposing methods to obtain "white" light without the aid of phosphors typically rely on a high-indium content layer deposited under conditions that result in poor material quality.


Additional Technologies by these Inventors


Tech ID/UC Case

22786/2004-208-0


Related Cases

2004-208-0


Country/Region

USA

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