Red-deficiency-compensating phosphor LED
US6351069B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 18, 1999 |
| Grant date | Feb 26, 2002 |
| Priority date | — |
| Expiry date | Feb 18, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10H20/8513
Abstract
A light emitting device and a method of fabricating the device utilize a supplementary fluorescent material that radiates secondary light in the red spectral region of the visible light spectrum to increase the red color component of the composite output light. The secondary light from the supplementary fluorescent material allows the device to produce “white” output light that is well-balanced with respect to color for true color rendering applications. The supplementary fluorescent material is included in a fluorescent layer that is positioned between a die and a lens of the device. The die is preferably a GaN based die that emits light having a peak wavelength of 470 nm. The fluorescent layer also includes a main fluorescent material. Preferably, the main fluorescent material is Cerium (Ce) activated and Gadolinium (Gd) doped Yttrium Aluminum Garnet (YAG) phosphor (“Ce:YAG phosphor”). In a first preferred embodiment, the supplementary fluorescent material is a compound that is produced by doping the Ce:YAG phosphor with a trivalent ion of Praseodymium (Pr). In a second preferred embodiment, the supplementary fluorescent material is Europium (Eu) activated…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.