Coordinate input device and display-integrated type coordinate input device capable of directly detecting electrostatic coupling capacitance with high accuracy
US6239788A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 7, 1998 |
| Grant date | May 29, 2001 |
| Priority date | — |
| Expiry date | Aug 7, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G3/3611
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
In a coordinate detection period, a first electrode drive circuit sequentially selects source electrodes Sn of the TFT LCD panel to connect the same to an x-signal current amplifying circuit, and to apply an AC voltage to the non-selected electrodes. The x-signal current amplifying circuit detects a detection current flowing through the selected electrode, the magnitude of which corresponds to a distance to a finger (or a conductor pen), to obtain an x-coordinate detection voltage. A second electrode drive circuit and a y-signal current amplifying circuit operate in similar fashion to obtain a y-coordinate detection voltage. A coordinate detection circuit then obtains the x- and y-coordinate values of the designated position based on the x-coordinate detection voltage and the y-coordinate detection voltage, thus enabling pointing by a codeless pen and a finger.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.