Liquid crystal display device and method of fabricating the same

1. A liquid crystal display device comprising:

a first substrate and a second substrate each having a display area and a non-display area defined;

a liquid crystal layer between the first and second substrates;

a light sensor on the first substrate in the non-display area that senses the intensity of external light;

a passivation layer on an entire upper surface of the first substrate including the light sensor; and

a dummy electrode on the passivation layer at a location corresponding to the light sensor and insulated from the light sensor with the passivation layer.

2. The liquid crystal display device according to claim 1 , wherein the dummy electrode is formed of a transparent conductive material.

3. The liquid crystal display device according to claim 1 , wherein the dummy electrode is formed of one of ITO and IZO.

4. The liquid crystal display device according to claim 1 , further comprising a black matrix positioned on the second substrate in the non-display area and having an opening exposing the light sensor.

5. The liquid crystal display device according to claim 1 , wherein when the liquid crystal display device is in a normally white mode, a constant voltage is applied to the dummy electrode that is different than the voltage applied to a common electrode.

6. The liquid crystal display device according to claim 1 , wherein when the liquid crystal display device is in a normally black mode, a voltage is applied to the dummy electrode that is the same as the voltage applied to a common electrode.

7. The liquid crystal display device according to claim 1 , wherein the light sensor includes a thin film transistor having a semiconductor layer whose current characteristic varies according to the intensity of light impinging on the semiconductor layer.

8. The liquid crystal display device according to claim 1 , further comprising a backlight whose brightness is controlled depending on an output signal from the light sensor.

9. A method of fabricating a liquid crystal display device, comprising:

providing a first substrate having a display area and a non-display area defined;

forming a light sensor on the first substrate in the non-display area to sense the intensity of external light and output an electrical signal;

forming a passivation layer on an entire upper surface of the first substrate including the light sensor; and

forming a dummy electrode on the passivation layer at a location corresponding to the light sensor and insulated from the light sensor with the passivation layer.

10. The method according to claim 9 , wherein the dummy electrode is formed of a transparent conductive material.

11. The method according to claim 9 , wherein the dummy electrode is formed of one of ITO and IZO.

12. The method according to claim 9 , further comprising:

providing a second substrate having a display area and a non-display area and having a black matrix formed in the non-display area of the second substrate; and

attaching the first substrate and the second substrate,

wherein the black matrix has an opening exposing the light sensor.

13. The method according to claim 9 , wherein a thin film transistor and a pixel electrode electrically connected with the thin film transistor are formed on the first substrate in the display area.

14. The method according to claim 13 , wherein the pixel electrode and the dummy electrode are formed of the same conductive material in the same layer.

15. The method according to claim 9 , wherein when the liquid crystal display device is in a normally white mode, the dummy electrode is electrically connected with a separate external voltage supply unit.

16. The method according to claim 9 , wherein when the liquid crystal display device is in a normally black mode, the dummy electrode is electrically connected with one of a common electrode and a common voltage supply unit.

17. The method according to claim 9 , wherein the light sensor includes thin film transistor having a semiconductor layer whose current characteristic varies according to the intensity of light impinging on the semiconductor layer.

18. The method according to claim 9 , further comprising assembling a backlight whose operation is controlled depending on an output signal from the light sensor.