Displaying gray shades on display panel implemented with active addressing technique
US5585816A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 6, 1995 |
| Grant date | Dec 17, 1996 |
| Priority date | — |
| Expiry date | Jun 6, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G3/2022
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Different gray shades or hues may be displayed in accordance with an active addressing technique that addresses faster responding passive matrix liquid crystal display panels (LCDs) so that video rate, high information content LCDs are perceived as having improved contrast by limiting peak voltage levels across the pixels. A preferred embodiment of the active addressing technique is implemented such that a first set of LCD electrodes is continuously driven with signals each comprising a train of pulses that are periodic in time, have a common period T, are independent of the information to be displayed, and are preferably orthonormal. Multiple column signals are generated from the collective information states of the pixels defined by the overlap with a second electrode pattern. Each column signal is proportional to the sum, obtained by considering each pixel in the column, of the exclusive-or (XOR) products of the logic level of the amplitude of each row signal times the logic level of the information state of the pixel corresponding to that row. Two alternative gray shading techniques provide for intermediate optical states between light and dark states. A frame modulation techni…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.