Light-sensing circuit, method of operating the light-sensing circuit, and light-sensing apparatus employing the light-sensing circuit

1. A light-sensing circuit comprising:

a light-sensing transistor configured to sense light; and

a switching transistor connected in series to the light-sensing transistor without a capacitor connected to a node between the light-sensing transistor and the switching transistor connected in series, the light-sensing transistor being a light-sensitive oxide semiconductor transistor including a light-sensitive oxide semiconductor as a channel layer, the light-sensing circuit being a pixel circuit;

a first gate line connected to a gate of the switching transistor;

a data line connected to a source of the switching transistor;

a driving voltage line connected to a drain of the light-sensing transistor;

a second gate line connected to a gate of the light-sensing transistor, wherein

the light-sensing circuit being configured to apply a low voltage to the switching transistor via the first gate line and to apply a high voltage to the light-sensing transistor via the second gate line during a standby time, and

the light-sensing circuit being configured to apply the high voltage to the switching transistor via the first gate line and to apply the low voltage to the light-sensing transistor via the second gate line if data is output.

2. The light-sensing circuit of claim 1 , wherein the high voltage is a higher voltage among a positive voltage that removes charges trapped in the light-sensing transistor and a voltage that turns ON the switching transistor, and the low voltage is a lower voltage among a threshold voltage of the switching transistor and a threshold voltage of the light-sensing transistor.

3. The light-sensing circuit of claim 1 , wherein the light-sensing transistor includes

a substrate,

an insulating layer on the substrate,

the gate of the light-sensing transistor on at least a portion of the insulating layer,

a gate insulating layer that covers at least a surrounding of the gate of the light-sensing transistor and is on the insulating layer and the gate of the light-sening transistor,

the channel layer on the gate insulating layer,

a source and the drain of the light-sensing transistor respectively covering ends of the channel layer, and

a transparent insulating layer on the source, the drain, and the channel layer,

wherein the channel layer includes the light-sensitive oxide semiconductor.

4. The light-sensing circuit of claim 1 , wherein the light-sensing transistor comprises:

a substrate;

the channel layer on the substrate;

a gate insulating layer on a center portion of the channel layer;

the gate of the light-sensing transistor on the gate insulating layer;

a source and the drain of the light-sensing transistor at an interval from the gate of the light-sensing transistor and on both sides of the gate of the light-sending transistor on the channel layer; and

a transparent insulating layer on the gate, the source, and the drain,

wherein the channel layer includes the light-sensitive oxide semiconductor.

5. The light-sensing circuit of claim 1 , wherein the light-sensitive oxide semiconductor includes a ZnO-based oxide.

6. The light-sensing circuit of claim 5 , wherein the ZnO-based oxide includes ZnO or a mixture including ZnO and at least one material selected from a group consisting of Hf, Y, Ta, Zr, Ti, Cu, Ni, Cr, In, Ga, Al, Sn, and Mg.

7. The light-sensing circuit of claim 1 , wherein a degree of sensitivity of the light-sensitive transistor is dependent on a color or a wavelength of light incident on the light-sensitive transistor.

8. The light-sensing circuit of claim 1 , wherein a degree of sensitivity of the light-sensitive transistor is dependent on an intensity of light incident on the light-sensitive transistor.

9. The light-sensing circuit of claim 1 , wherein a degree of sensitivity of the light-sensitive transistor is dependent on a color and an intensity of light incident on the light-sensitive transistor.

10. A light-sensing apparatus comprising:

a light-sensing panel configured to sense incident light;

a gate driver configured to provide a gate voltage to the light sensing panel;

a data driver configured to measure an output of the light sensing panel; and

an analog digital (A/D) converter (ADC) configured to convert an analog signal output by the data driver into a digital signal,

wherein the light-sensing panel includes an array of a plurality of light-sensing pixels, each of the light-sensing pixels including the light-sensing circuit of claim 1 .

11. The light-sensing apparatus of claim 10 , wherein the light-sensing panel further comprises:

a plurality of first gate lines and second gate lines as rows, and

a plurality of driving voltage lines and data lines as columns.

12. The light-sensing apparatus of claim 11 , wherein the first and second gate lines are connected to the gate driver, and the data lines are connected to the data driver.

13. The light-sensing apparatus of claim 12 , wherein the gate driver is configured to sequentially provide a gate voltage to rows of the light-sensing pixels via the first and second gate lines.

14. The light-sensing apparatus of claim 10 , wherein the light-sensing apparatus is an image acquisition device, or a remote optical touch panel.

15. The light-sensing circuit of claim 1 , wherein a source of the light-sensing transistor is connected to a drain of the switching transistor.

16. The light-sensing circuit of claim 1 ,

the light-sensing transistor includes source and drain electrodes, and

the light-sensitive oxide semiconductor is directly connected to the source and drain electrodes of the light-sensing transistor.

17. A light-sensing circuit comprising:

a light-sensing transistor configured to sense light;

a switching transistor connected in series with the light-sensing transistor,

the light-sensing transistor being a light-sensitive oxide semiconductor transistor including a light-sensitive oxide semiconductor as a channel layer, and

a source of the light-sensing transistor being configured to be electrically connected in series to a drain of the switching transistor independent of whether the switching transistor is on or off and independent of whether the light-sensing transistor is on or off;

a first gate line connected to a gate of the switching transistor;

a data line configured to be electrically connected to a source of the switching transistor independent of whether the switching transistor is on or off;

a driving voltage line configured to be electrically connected to a drain of the light-sensing transistor independent of whether the light-sensing transistor is on or off; and

a second gate line connected to a gate of the light-sensing transistor, wherein the driving voltage line and the second gate line are electrically separated from each other, and the light-sensing circuit is a pixel circuit, wherein

the light-sensing circuit is configured to apply a low voltage to the switching transistor via the first gate line and to apply a high voltage to the light-sensing transistor via the second gate line during a standby time,

the light-sensing circuit is configured to apply the high voltage to the switching transistor via the first gate line and to apply the low voltage to the light-sensing transistor via the second gate line if data is output through the switching transistor, and

the switching transistor is connected in series to the light-sensing transistor without a capacitor connected to a node between the light-sensing transistor and the switching transistor connected in series.

18. The light-sensing circuit of claim 17 , wherein

the switching transistor does not have light-sensing characteristics.

19. The light-sensing circuit of claim 17 , wherein

the light-sensitive oxide semiconductor is directly connected to the source and drain of the light-sensing transistor, and wherein

the light-sensing circuit is configured to apply a high voltage to the drain of the light-sensing transistor using the driving voltage line while simultaneously applying a low voltage of the to the gate of the light-sensing transistor.

20. The light-sensing circuit of claim 17 , wherein the high voltage is a higher voltage among a positive voltage that removes charges trapped in the light-sensing transistor and a voltage that turns ON the switching transistor, and the low voltage is a lower voltage among a threshold voltage of the switching transistor and a threshold voltage of the light-sensing transistor.

21. The light-sensing circuit of claim 4 , wherein the source and drain are each formed of a material that is one of,

a conductive metal oxide that is different than a material of the light-sensitive oxide semiconductor, and

a conductive metal.

22. The light-sensing circuit of claim 17 , wherein

the source and drain of the light-sensing transistor are each formed of a material that is one of,

a conductive metal oxide that is different than the light-sensitive oxide semiconductor in the channel layer, and

a conductive metal.