Multi element, multi color solid state LED/laser
US7084436B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 31, 2004 |
| Grant date | Aug 1, 2006 |
| Priority date | — |
| Expiry date | Mar 31, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10H29/14
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A light emitting diode (LED) grown on a substrate doped with one or more rare earth or transition element. The dopant ions absorb some or all of the light from the LED's active layer, pumping the electrons on the dopant ion to a higher energy state. The electrons are naturally drawn to their equilibrium state and they emit light at a wavelength that depends on the type of dopant ion. The invention is particularly applicable to nitride based LEDs emitting UV light and grown on a sapphire substrate doped with chromium. The chromium ions absorb the UV light, exciting the electrons on ions to a higher energy state. When they return to their equilibrium state they emit red light and some of the red light will emit from the LED's surface. The LED can also have active layers that emit green and blue and UV light, such that the LED emits green, blue, red light and UV light which combines to create white light. Alternatively, it can have one active layer and grown on a sapphire substrate doped with Cr, Ti, and Co such that the substrate absorbs the UV light and emits blue, green, and red light. The invention is also capable of providing a tunable LED over a variety of color shades. The inve…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.