In-cell capacitive touch panel
First Claim
1. An in-cell capacitive touch panel comprising:
- a first gate line;
a second gate line; and
a sensing unit comprising;
at least one sensing liquid crystal capacitor;
a first transistor,being controlled by said first gate line to charge said sensing liquid crystal capacitor and to generate a reference voltage at a first electrode of said sensing liquid crystal capacitor, and comprisinga drain being connected to said first gate line;
a source being connected to said sensing liquid crystal capacitor; and
a gate being connected to said first gate line and said sensing liquid crystal capacitor, wherein said reference voltage is adjusted based on a voltage of said first gate line and a voltage variation Δ
Vp of said reference voltage is expressed by an equation;
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Abstract
An in-cell capacitive touch panel is disclosed. The present invention utilizes a sensing unit that comprises a sensing liquid crystal capacitor and three transistors to detect touch events. A first transistor is connected to a first gate line and the sensing liquid crystal capacitor and controlled by the first gate line to charge the sensing liquid crystal capacitor. A second transistor together with a third transistor functions as a capacitance-current converter. The second transistor generates an output current according to the voltage of a first electrode of the sensing liquid crystal capacitor. A second gate line controls the third transistor to transfer the output current through a readout line to a readout unit that determines the touch positions. Thus, the in-cell capacitive touch panel of the present invention can use a simple-structure readout circuit to achieve superior readout accuracy and is adaptive to various sizes of touch panels.
24 Citations
20 Claims
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1. An in-cell capacitive touch panel comprising:
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a first gate line; a second gate line; and a sensing unit comprising; at least one sensing liquid crystal capacitor; a first transistor, being controlled by said first gate line to charge said sensing liquid crystal capacitor and to generate a reference voltage at a first electrode of said sensing liquid crystal capacitor, and comprising a drain being connected to said first gate line; a source being connected to said sensing liquid crystal capacitor; and a gate being connected to said first gate line and said sensing liquid crystal capacitor, wherein said reference voltage is adjusted based on a voltage of said first gate line and a voltage variation Δ
Vp of said reference voltage is expressed by an equation; - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. An in-cell capacitive touch panel comprising:
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a first gate line and a second gate line; and a sensing unit further comprising; a sensing liquid crystal capacitor; a first transistor, wherein a gate and a drain of said first transistor are connected to said first gate line, and a source of said first transistor is connected to a first electrode of said sensing liquid crystal capacitor; a second transistor, wherein a gate of said second transistor is connected to said source of said first transistor and said first electrode of said sensing liquid crystal capacitor; and a third transistor, wherein a gate, a drain and a source of said third transistor are respectively connected to said second gate line, a drain of said second transistor and a readout line, wherein a drain of said first transistor is connected to said first gate line;
a source of said first transistor is connected to said sensing liquid crystal capacitor;
a gate of said first transistor is connected to both said first gate line and said sensing liquid crystal capacitor;
said first transistor is controlled by said first gate line to charge said sensing liquid crystal capacitor and generate a reference voltage at the first electrode of said sensing liquid crystal capacitor;
when a voltage of said first gate line rapidly descends from a high voltage level to a low voltage level, generating a voltage drop Δ
Vg, a voltage variation Δ
Vp of said reference voltage is expressed by an equation; - View Dependent Claims (18, 19, 20)
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Specification