Liquid crystal display device using signal converter of digital type
US4180813A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 26, 1977 |
| Grant date | Dec 25, 1979 |
| Priority date | — |
| Expiry date | Jul 26, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G3/2014
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A liquid crystal display device capable of displaying halftone pictures comprises a liquid crystal display panel in which liquid crystal picture elements are provided at the intersections of the m scanning electrodes and the n signal electrodes arranged in matrix configuration so as to be selectively lit up, a first liquid crystal drive circuit for selectively applying scanning voltages to the m scanning electrodes, a second liquid crystal drive circuit for applying brightness signal voltages to the n signal electrodes, wherein the signal converting circuit for supplying the n brightness signal voltages corresponding to the n signal electrodes to the second liquid crystal drive circuit in synchronism with the scanning voltages is simplified by constructing all the component circuits, except the A/D converter, in digital fashion so that it can be easily integrated and that every signal electrode need not be provided with a brightness control circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.