Method for driving a ferroelectric liquid crystal optical apparatus using superposed DC and AC driving pulses to attain intermediate tones
US4834510A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 9, 1988 |
| Grant date | May 30, 1989 |
| Priority date | — |
| Expiry date | May 9, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G2310/06
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The present invention realizes display of the intermediate tone by shortening the selection period of the one scanning line and setting a mean voltage level applied to the pixels to 0 by selectively applying the pulse, to the pixels, for initializing the ferroelectric liquid crystal to the saturated reverse response condition and the pulse superposing the high frequency AC pulse to the pulse having a mean voltage of 0 for such pulse and then applying the AC pulse which holds the response condition of ferroelectric liquid crystal while such pulse group is not applied to the pixels, and moreover by controlling a voltage value or duty (rate of the period for applying high frequency AC pulse and the period for not applying the pulse) of the high frequency AC pulse to be superposed to such pulse depending on the display tone.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.