DC-balanced and non-DC-balanced drive schemes for liquid crystal devices
US6507330B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 14, 2001 |
| Grant date | Jan 14, 2003 |
| Priority date | — |
| Expiry date | Mar 14, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G2320/0257
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method of operating a liquid crystal cell includes DC-balancing by displaying an inverse image with electric fields of increased magnitude relative to the image producing electric fields. While the inverse image is displayed the image is prevented from being visible by either turning off the light source or re-directing or blocking the light from reaching the viewing area. The image producing electric fields and the inverse image producing electric fields are such that the cumulative time integral of the electric fields that are present in one direction across the liquid crystal material is substantially equal to the cumulative time integral of the electric fields that are present in the opposite direction during the given period of time during the operation of liquid crystal cell. The time duration of the inverse image portion is shorter than the time duration of the image portion by an amount proportional to the increased magnitude of the additional electric fields. Because of the shorter time period when no image is visible, the system brightness is increased.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.