Apparatus for detecting X-rays and method of operating the same

1. A method for driving an X-ray detecting apparatus, comprising:

sampling a first data voltage corresponding to a rheobase voltage and a bias voltage, said rheobase voltage being generated by a current from a photodiode;

sampling a second data voltage corresponding to the bias voltage after resetting the rheobase voltage; and

resetting the rheobase voltage from the time that the sampling of the second data voltage is finished to the time that a corresponding frame is finished.

2. The method of claim 1 , wherein the sampling of the first data voltage comprises:

applying a scan signal to turn on a switching transistor, the switching transistor switching a current corresponding to the rheobase voltage to generate the first data voltage; and

applying the first data voltage to a data detector through the turned-on switching transistor.

3. The method of claim 2 , wherein the sampling of the second data voltage comprises:

applying a reset signal to a reset transistor resetting the rheobase voltage;

applying the scan signal to turn on the switching transistor and to generate the second data voltage; and

applying the second data voltage to the data detector through the turned-on switching transistor.

4. The method of claim 1 , further comprising removing electrical noise by obtaining a difference between the first data voltage and the second data voltage.

5. An X-ray detecting apparatus, comprising:

an X-ray receiving panel including a photo-detecting pixel;

a data detector detecting a data signal from which noise is removed from a signal output from the X-ray receiving panel through noise sampling; and

a reset driver applying a reset signal to the photo-detecting pixel, said reset signal resetting a rheobase voltage generated by the photo-detecting pixel for the noise sampling,

the reset driver applying the reset signal after detecting the data signal from which the noise is removed in the data detector until the time that a corresponding frame is finished.

6. The X-ray detecting apparatus of claim 5 , wherein the photo-detecting pixel includes:

a photodiode generating a first current corresponding to visible rays incident through a scintillator layer;

a capacitor being charged by the first current generated in the photodiode;

a driving transistor passing a second current corresponding to a voltage charged to the capacitor;

a switching transistor switching the second current flowing in through the driving transistor; and

a reset transistor resetting the voltage charged to the capacitor.

7. The X-ray detecting apparatus of claim 6 , wherein the photodiode is a hydrogenated amorphous silicon PIN diode.

8. The X-ray detecting apparatus of claim 6 , wherein the switching transistor is a low temperature polysilicon thin film transistor (TFT).

9. The X-ray detecting apparatus of claim 6 , wherein the reset transistor is a low temperature polysilicon TFT.

10. The X-ray detecting apparatus of claim 6 , further comprising a scan driver applying a scan signal to a scan line connected to a gate electrode of the switching transistor, said scan signal turning on or turning off the switching transistor.

11. The X-ray detecting apparatus of claim 10 , further comprising a signal controller generating a reset driving signal controlling the operation of the reset driver and generating a scan driving signal controlling the operation of the scan driver.