Cumulative drive scheme and method for a liquid crystal display
US6133895A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 4, 1997 |
| Grant date | Oct 17, 2000 |
| Priority date | — |
| Expiry date | Jun 4, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G2310/04
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A liquid crystal display including driver circuitry which applies a series of voltage pulses at a frequency of approximately 60 Hz. to cumulatively change a reflectance state of a pixel in an array of pixels at a near video updating rate. The display includes a near video rate updating portion, while the remainder of the display has a slower updating frequency or rate. The display is comprised of a bistable cholesteric liquid crystal material sandwiched between an electrode array having a plurality of row and column electrodes. In one operating embodiment, the driver circuitry generates a unipolar row and column waveforms, the row waveforms being applied to the row electrodes and the column waveforms being applied to the column electrodes of the near video rate updating portion. Approximately every 16 milliseconds, a pixel in the near video rate updating portion receives a control voltage pulse corresponding to the difference between the row and column waveforms. Application of six to seven control voltage pulses is sufficient to change the reflectance state of the pixel. In a second operating embodiment, the driver circuitry generates bipolar row and column waveforms. In alternate…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.