Light emitting diode device comprising a luminescent substrate that performs phosphor conversion
US6630691B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 27, 1999 |
| Grant date | Oct 7, 2003 |
| Priority date | — |
| Expiry date | Sep 27, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10H20/851
Abstract
The present invention provides an LED device comprising a phosphor-converting substrate that converts primary light emitted by the LED, which is blue light, into one or more other wavelengths of light, which then combine with unconverted primary light to produce white light. The substrate is a single crystal phosphor having desired luminescent properties. The single crystal phosphor has the necessary lattice structure to promote single crystalline growth of the light-emitting structure of the LED device. Moreover, the thermo-mechanical properties of the substrate are such that the introduction of excessive strain or cracks in the epitaxial films of the LED device is prevented. The characteristics of the substrate, i.e., the dopant concentration and thickness, are capable of being precisely controlled and tested before the LED device is fabricated so that the fraction of primary light that passes through the substrate without being converted is predictable and controllable. Likewise, the fraction of primary light that is converted by the substrate into one or more other wavelengths is predictable and controllable. By precisely controlling these fractions, phosphor-converted LED devi…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.