Methods and means for testing faults in a liquid crystal display system
US4734688A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 27, 1985 |
| Grant date | Mar 29, 1988 |
| Priority date | — |
| Expiry date | Aug 27, 2005 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S345/904
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method and arrangement for providing a continuous visual check on the operation of a standard liquid crystal display by superimposing a checking signal upon the operating signals applied to the individual segment and back electrodes of the LCD through individual impedance paths substantially higher than the individual impedance paths carrying the operating signal to the segment and back electrodes so that the operating signal overrides the checking signal under normal circumstances but the checking signal overrides the operating signal when the latter is interrupted due to a fault. The checking signal causes the segment electrode or back electrode whose signal is impaired to blink at a visually perceptible rate. Preferably, the frequency of the checking signal is in the order of 0.5 Hz to 2.0 Hz.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.