Chroma compensated backlit display
US7339332B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 24, 2004 |
| Grant date | Mar 4, 2008 |
| Priority date | — |
| Expiry date | May 3, 2026 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G2320/0666
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Methods and apparatus are provided for a backlit display with variable luminance and chrominance. The apparatus comprises i groups of LEDs of different colors and one or more sensors optically coupled to the LEDs. The combined light produced by the LEDs is directed to a transmissive liquid crystal display, preferably through a diffusing layer. The sensors monitor the output Si of each group of LEDs. Si for each group of LEDs is multiplied by a chrominance determining parameter Ki to obtain Ki*Si which is then compared to a commanded luminance signal LC to obtain LC−Ki*Si, which difference is used to adjust the drive current to each group of LEDs to achieve LC with the desired chrominance set by Ki. By changing Ki and LC the chrominance and luminescence of the display may be varied and aging effects compensated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.