Patent ID: 8451233

Claim:
A sensor pixel of a touch panel having m scan lines and n readout lines, the sensor pixel comprising: a sensing capacitor, having a first terminal and a second terminal, wherein a voltage across the sensing capacitor is read out through the j th readout line while the i th scan line is asserted, the voltage is employed to determine whether the sensor pixel is touched, and the sensor pixel is judged to be touched while the voltage across the sensing capacitor is greater than a presetting voltage; a readout transistor, having a gate coupled to the i th scan line, a first source/drain coupled to the j th readout line and a second source/drain coupled to the first terminal of the sensing capacitor, wherein 1≦i≦m and 1≦j≦n; a reset transistor, having a gate coupled to the (i+1) th scan line, a first source/drain coupled to the second terminal of the sensing capacitor and a second source/drain coupled to a first voltage; a base transistor, having a gate receiving an inverted signal of the i th scan line, a first source/drain coupled to the first terminal of the sensing capacitor and a second source/drain coupled to a second voltage, wherein when the i th scan line is unasserted, the base transistor is turned on, and when the i th scan line is asserted, the base transistor is turned off; and a photo transistor, having a gate coupled to the i th scan line, a first source/drain coupled to the second terminal of the first capacitor and a second source/drain coupled to the second voltage, wherein the photo transistor is conducted when it is exposed to a light.