Minimizes the re-absorption of LED light by using transparent conductive oxide electrodes (ITO or ZnO) instead of mirrors.
Conventional LEDs utilize mirrors in order to increase the front emissions of particular wavelengths of light by reflecting the LED light forward. In order to increase the output power for the front side of the LED, the emitting light is reflected by the mirror on the backside of the sapphire substrate. These reflected emissions are partly re-absorbed by the active layer of the LED, reducing the output power and efficient of the LED.
An invention created by UC Santa Barbara researchers minimizes the re-absorption of LED light by using transparent conductive oxide electrodes (ITO or ZnO) instead of mirrors. This type of LED also employs a gallium nitride substrate instead of a sapphire substrate in order to create more efficient quantum wells and utilizes textured phosphor layers in order to increase luminous efficacy. The combination of transparent conductive oxide electrodes with a nitride LED and a shaped lens results in high levels of light extraction.
|United States Of America||Issued Patent||7,781,789||08/24/2010||2007-273|
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