06239788 is referenced by 190 patents and cites 14 patents.

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.

Title
Coordinate input device and display-integrated type coordinate input device capable of directly detecting electrostatic coupling capacitance with high accuracy
Application Number
9/131394
Publication Number
6239788 (B1)
Application Date
August 7, 1998
Publication Date
May 29, 2001
Inventor
Hiroyuki Iwahashi
Kyoto-fu
US
Kengo Takahama
Nara
US
Kiyohiro Nozaki
Nara
US
Masayuki Katagiri
Ikoma
US
Hitoshi Nohno
Nabari
US
Assignee
Sharp Kabushiki Kaisha
US
IPC
G09G 5/00
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