Display apparatus capable of image scanning and driving method thereof

1. A display apparatus capable of image scanning, the apparatus comprising a contact sensor arranged in each unit pixel, wherein the contact sensor comprises:

a pixel electrode forming a contact capacitance by contact with a contact means;

a reset transistor where a drain electrode is connected to a node where the contact capacitance is formed, and each of a gate electrode and a source electrode is connected to a first scan line to which a first selective signal is applied;

an amplifying transistor where a gate electrode is connected to the drain electrode of the reset transistor, and a source electrode is connected to a power input terminal; and

a detecting transistor where a drain electrode is connected to the drain electrode of the amplifying transistor, a gate electrode is connected to a second scan line to which a second selective signal is applied, and a source electrode is connected to a readout line detecting a current corresponding to the contact capacitance.

2. The display apparatus of claim 1 , wherein the reset transistor, the amplifying transistor, and the detecting transistor are arranged so as not to overlap a unit color pixel in a color filter layer, and wherein the pixel electrode is arranged to overlap at least a part of the unit color pixel.

3. The display apparatus of claim 1 , wherein the amplifying transistor generates a current varying depending on a voltage charged in the contact capacitance and delivers the generated current to the detecting transistor.

4. The display apparatus of claim 1 , wherein the detecting transistor is turned on by the second selective signal from the second scan line and delivers to the readout line the current generated by the amplifying transistor.

5. The display apparatus of claim 1 , wherein the second selective signal applied to the second scan line is applied after the first selective signal is applied to the first scan line.

6. The display apparatus of claim 1 , wherein the reset transistor, the amplifying transistor, and the detecting transistor are formed of a transparent thin film transistor and overlap at least a part of the unit color pixel in a color filter layer.

7. The display apparatus of claim 1 , determining whether contact is made to an upper part of the contact sensor and contact condition, based on the current of the readout line detected after the selective signal is supplied to the first and second scan lines.

8. The display apparatus of claim 1 , wherein a passivation layer is formed between the pixel electrode, and the reset transistor, the amplifying transistor and the detecting transistor, and

wherein the pixel electrode is connected to the drain electrode of the reset transistor or the gate electrode of the amplifying transistor through a contactor formed through an end of the passivation layer.

9. The display apparatus of claim 1 , wherein the pixel electrode is arranged opposite to a substrate in which the reset transistor, the amplifying transistor, and the detecting transistor are arranged, and

wherein the pixel electrode is connected to the drain electrode of the reset transistor or the gate electrode of the amplifying transistor through a via formed through an end of the substrate.

10. The display apparatus of claim 1 , further comprising a data line,

wherein at least a part of the reset transistor, the amplifying transistor, the detecting transistor, the pixel electrode, and the signal line constituting each contact sensor of a pair of contact sensors unidirectionally arranged are symmetrical with respect to the data line or the readout line arranged between the pair of contact sensors.

11. A display apparatus capable of image scanning, the apparatus comprising a sensor array layer comprising a contact sensor arranged in each unit pixel and a color filter layer comprising a unit color pixel comprising each of a red pixel, a green pixel and a blue pixel, wherein the contact sensor comprises:

a transparent pixel electrode forming a contact capacitance by contact with a contact means and arranged to overlap the unit color pixel in the color filter layer;

a reset transistor receiving a first selective signal from a first scan line through each of a gate electrode and a source electrode and delivering the first selective signal to the contact capacitance;

an amplifying transistor generating a current varying depending on a voltage charged in the contact capacitance; and

a detecting transistor receiving a second selective signal from a second scan line and detecting the current to deliver the current to a readout line,

wherein the reset transistor, the amplifying transistor, and the detecting transistor are arranged so as not to overlap the unit color pixel in the color filter layer.

12. A method for driving a display apparatus comprising a contact sensor arranged in each unit pixel, the method comprising:

charging a contact capacitance formed between a pixel electrode and a contact means through a reset transistor turned on by receiving a first selective signal from a first scan line through each of a gate electrode and a source electrode of the reset transistor;

generating a current varying depending on a voltage charged in the contact capacitance through an amplifying transistor, a gate electrode of the amplifying transistor being connected to a drain electrode of the reset transistor; and

detecting the generated current through a detecting transistor turned on by receiving a second selective signal from a second scan line, to determine whether contact is made to an upper part of the contact sensor and contact condition.