Liquid crystal flat panel display with enhanced backlight brightness and specially selected light sources
US6657607B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 19, 2001 |
| Grant date | Dec 2, 2003 |
| Priority date | — |
| Expiry date | Jan 23, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/133507
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Brightness in the LCD is enhanced by polarization recycling using a pre-polarizing film to pre-polarize light, and a special reflector for recycling light reflected by the pre-polarizing film. In one embodiment, the pre-polarizing film comprises a layer of DBEF brightness enhancement film, and the rear reflector is made of a PTFF material. In another embodiment, the rear reflector is covered with a film comprising barium sulfate. The multiple light sources are selected such that, at any color temperature within a predetermined range, the brightness of the LCD is not reduced below a given threshold minimum (e.g., 70 percent of the maximum brightness). Another constraint for selecting the light sources is that within the predetermined color temperature range, the color temperature is held close to the black body curve of the CIE chromaticity diagram. The light sources are also selected so that their maximum brightness point is set to be near the middle of the predetermined color temperature range.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.