Matrix display device with write-in facility
US5485177A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 26, 1991 |
| Grant date | Jan 16, 1996 |
| Priority date | — |
| Expiry date | Nov 26, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F3/042
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An active matrix liquid crystal display device in which an array of picture elements which include respective switching means, e.g. TFTs, are driven a row at a time by drive signals supplied via a set of row and a set of column address conductors. The device also includes an array of active addressed sensing elements each consisting of a photosensitive element, e.g. a thin film photoresistor or photodiode, a charge storage capacitor and a switching device, e.g. a TFT. The sensing element connected to respective row and column address conductors. The charge storage capacitors are periodically charged through operation of their associated switching devices by the drive signals and are selectively discharged via their associated photosensitive element when illuminated by, for example, a light pen. The states of the charge storage capacitors of all of the sensing elements are determined, one row at a time, by a detection circuit connected to the column address conductors during each display field period in synchronism with the driving of the rows of picture elements.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.