Voltage tuning of LCD polarization state by varying drive voltage to compensate for optical misalignment
US6177967A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 28, 1998 |
| Grant date | Jan 23, 2001 |
| Priority date | — |
| Expiry date | Sep 28, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/13306
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method of modifying the polarization state of light exiting a Liquid Crystal Display that is effected without altering the optical image of the display comprises reducing the select voltage to the LCD cell to less than the saturation select voltage. In one embodiment of an apparatus incorporating features of the present invention, a color LCD display is constructed using two or more LCD cells that are aligned to produce an optimum image through the display optics. One or more of the LCD cells are then driven to the dark state at a select voltage that is less than the saturation select voltage for that cell. By operating the LCD cell at less than the saturation select voltage, the polarization state of the light exiting a dark selected pixel compensates for the misalignment between the saturation voltage polarization axis of the display and the system polarization axis of the optics. Accordingly, the selected pixel appears darker than would the same pixel driven at the saturation voltage. By operating the LCD cell at less than the saturation select voltage, higher contrast ratios and improved color saturation is achieved without sacrificing image quality.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.