Patent ID: 8044943

Claim:
A touch panel, comprising: a bias line, biased at a bias voltage; a select line; a readout line; a photo cell, comprising: a first photo TFT, having a first terminal, a second terminal and a control terminal, wherein the first terminal is coupled to the readout line and the control terminal is coupled to the select line; a second photo TFT, having a first terminal, a second terminal and a control terminal, wherein the first terminal is coupled to the readout line, the second terminal and the control terminal are coupled to the bias line; and a storage capacitor, coupling the second terminal of the first photo TFT to the bias line; a readout circuit comprising: an operational amplifier, having an inverting input terminal, a non-inverting input terminal and an output terminal, wherein the inverting input terminal is coupled to the readout line; a feedback capacitor, coupled between the inverting input terminal and the output terminal of the operational amplifier; and a first switch, coupled between the inverting input terminal and the output terminal of the operational amplifier, and a multiplexer for selectively outputting a reference voltage or the bias voltage to the non-inverting input terminal.