AC TFEL device having a white light emitting multilayer phosphor
US5598059A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 19, 1995 |
| Grant date | Jan 28, 1997 |
| Priority date | — |
| Expiry date | Apr 19, 2015 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/00
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An AC thin film electroluminescent (TFEL) device includes a multilayer phosphor for emitting white light having improved emission intensity in the blue region of the spectrum. The multilayer stack consists of an inverted structure thin film stack having a red light emitting manganese doped zinc sulfide (ZnS:Mn) layer disposed on a first insulating layer; a blue-green light emitting cerium doped strontium sulfide (SrS:Ce) layer disposed on the red light emitting layer; and a blue light emitting cerium activated thiogallate phosphor (Sr.sub.x Ca.sub.1-x Ga.sub.2 S.sub.4 :Ce) layer disposed on the blue-green light emitting layer. The manganese doped zinc sulfide layer acts as a nucleating layer that lowers the threshold voltage, and the cerium activated thiogallate phosphor layer provides a moisture barrier for the hydroscopic cerium doped strontium sulfide layer. The white light from the multilayer phosphor can be appropriately filtered to produce any desired color.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.