The world’s first monolithic white LED structure produces light with a color quality very close to that produced by incandescent lamps and sun light on Earth. The Kamiyama LED combines the very low energy consumption of LED light sources with a high color quality – similar to that of halogen lighting. The management believes that the Kamiyama LED will be the first choice for consumers of indoor lighting and in LCD backlighting applications. The Kamiyama LED combines:
- a high energy efficient,
- a high color quality and stability
- a highly efficient heat transport with
- a long lifetime.
The Kamiyama LED does not contain mercury like compact fluorescent lamps.
Monolithic Device
The key technologies in the Kamiyama LED are the florescent silicon carbide substrate, the near-UV excitation source and the moth-eye structure for enhanced light extraction efficiency.
The monolithic device structure of the Kamiyama LED is represented in the schematic figure below:
Excitation source
A near UV GaN LED with a central wavelength of λ=385 nm is used to excite the Kamiyama LED.
Conversion Mechanism
The near UV excitation light is converted in the fluorescent silicon carbide layers to white light in two broad peaks covering the visible region.
Spectrum
The CIE chromaticity coordinates can be determined by the respective thicknesses of the N-B and N-Al doped layers as detailed in the diagram below.
Moth-eye Patterned Substrate
To achieve a high light extraction efficiency the silicon carbide to resin interface is patterned with a nano scale moth-eye structure.
Electrode Structure
Electric connections are established by gold bumps to a ceramic substrate.
Heat Transport
The operation temperature of the Kamiyama LED is 200 degrees centigrade. The high operation temperature enables a 40% higher heat transport in heat sinks compared to what is typical in phosphor coated white LED’s.
