Image displaying and capturing devices

1. A system for displaying and capturing images, comprising:

a display unit providing a first light according to a scan signal and a data signal,

wherein the data signal is transmitted to the display unit through a data line; and

a detection module capturing a second light and comprising:

a photo detection unit detecting intensity of the second light;

a transformation unit coupled to the photo detection unit at a first point and transforming the light intensity into a voltage signal, wherein the transformation unit comprises:

a P-type transistor comprising a gate couple to the first point, a source receiving the high voltage level, and a drain outputting the voltage signal; and

an N-type transistor comprising a gate coupled to the first point, a source receiving the low voltage level, and a drain coupled to the drain of the P-type transistor; and

a switch unit comprising a transistor which comprises a gate receiving a selection signal, a source outputting the voltage signal through the data line according to the selection signal, and a drain coupled to the drain of the P-type transistor.

2. The system as claimed in claim 1 , wherein the photo detection unit comprises:

a capacitor coupled between the first point and a low voltage level; and

a photo sensor parallel with the capacitor and comprising a conductance that changes according to the light intensity for controlling discharge time of the capacitor.

3. The system as claimed in claim 2 , further comprising a pre-charge module for charging the capacitor, wherein the pre-charge module stops charging the capacitor when voltage stored in the capacitor reaches a high voltage level.

4. The system as claimed in claim 3 , further comprising a reading module coupled to the source of the transistor for reading the voltage signal.

5. The system as claimed in claim 4 , wherein the reading module calculates the voltage signal through an integral method or a differential method.

6. The system as claimed in claim 1 , further comprising:

a gate driver providing the scan signal and the selection signal; and

a source driver providing the data signal.

7. The system as claimed in claim 6 , wherein the frequency of the scan signal exceeds that of the selection signal.

8. The system as claimed in claim 1 , wherein the system is implemented as at least one of a digital camera, a portable DVD, a television, a car display, a PDA, a display monitor, a notebook computer, a tablet computer, or a cellular phone.

9. The system as claimed in claim 1 , wherein the second light is a reflected light from a surface of an object when the surface of the object is irradiated by the first light.

10. The system as claimed in claim 9 , further comprising a reading module for reading the voltage signal and determining a gray level of the surface of the object according to the voltage signal.

11. A system for displaying and capturing images, comprising:

a display unit providing a first light according to a scan signal and a data signal; and

a detection module capturing a second light and comprising;

a photo detection unit detecting intensity of the second light;

a transformation unit transforming the light intensity into a voltage signal, wherein the transformation unit comprises:

a P-type transistor comprising a gate couple to the first point, a source receiving the high voltage level, and a drain outputting the voltage signal; and a N-type transistor comprising a gate coupled to the first point, a source receiving the low voltage level, and a drain coupled to the drain of the P-type transistor; and

a switch unit comprising a transistor which comprises a gate receiving the selection signal, a source outputting the voltage signal according to the selection signal, and a drain coupled to the drain of the P-type transistor.

12. The system as claimed in claim 11 , wherein the photo detection unit comprises:

a capacitor coupled between a first point and a low voltage level; and

a photo sensor parallel with the capacitor and comprising a conductance that changes according to the light intensity for controlling discharge time of the capacitor.

13. The system as claimed in claim 12 , further comprising a pre-charge module for charging the capacitor, wherein the pre-charge module stops charging the capacitor when voltage stored in the capacitor reaches a high voltage level.

14. The system as claimed in claim 11 ,

wherein the system further comprises a reading module coupled to the source of the transistor for reading the voltage signal.

15. The system as claimed in claim 11 , further comprising:

a gate driver providing the scan signal and the selection signal; and

a source driver providing the data signal, wherein the frequency of the scan signal exceeds that of the selection signal.

16. The system as claimed in claim 11 , wherein the system is implemented as at least one of a digital camera, a portable DVD, a television, a car display, a PDA, a display monitor, a notebook computer, a tablet computer, or a cellular phone.