LIGHT-SENSING APPARATUSES, METHODS OF DRIVING THE LIGHT-SENSING APPARATUSES, AND OPTICAL TOUCH SCREEN APPARATUSES INCLUDING THE LIGHT-SENSING APPARATUSES

• US 20130027326A1
• Filed: 05/07/2012
• Published: 01/31/2013
• Est. Priority Date: 07/28/2011
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Young, Song, I-hun, Jeon, Sang-hun, Ahn, Seung-eon, Goh, Joon-chul, Lee, Cheol-gon
• Granted Patent: US 9,268,428 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/042 by opto-electronic means

Abstract

A light-sensing apparatus in which a light sensor transistor in a light-sensing pixel is formed of an oxide semiconductor transistor for sensing light, a method of driving the light-sensing apparatus, and an optical touch screen apparatus including the light-sensing apparatus. The light-sensing apparatus includes a light-sensing pixel array having a plurality of light-sensing pixels arranged in rows and columns, and a plurality of gate lines which are arranged in a row direction and respectively provide a gate voltage to the light-sensing pixel. Each of the light-sensing pixels includes a light sensor transistor for sensing light and a switch transistor for outputting a light-sensing signal from the light sensor transistor, and gates of the light sensor transistors of the light-sensing pixels arranged in an arbitrary row are connected to a gate line arranged in a row previous or next to the arbitrary row.

Claims

1. A light-sensing apparatus, comprising:

a light-sensing pixel array including a plurality of light-sensing pixels in a plurality of rows and a plurality of columns, each of the light-sensing pixels including a light sensor transistor configured to sense light and a switch transistor configured to output a light-sensing signal from the light sensor transistor; and

a plurality of gate lines configured to apply a gate voltage to the light-sensing pixels, a gate of the light sensor transistor in a first row of the plurality of rows being connected to a gate line in a second row of the plurality of rows.

2. The light-sensing apparatus of claim 1, wherein each of the gate lines is connected to a plurality of the light-sensing pixels in a same row.

3. The light-sensing apparatus of claim 1, wherein each of the gates lines is connected to gates of a plurality of the switch transistors in a same row.

4. The light-sensing apparatus of claim 3, wherein the switch transistor and the light sensor transistor in each of the light-sensing pixels are connected in series.

5. The light-sensing apparatus of claim 1, wherein the first row is immediately adjacent to the second row.

6. The light-sensing apparatus of claim 1, wherein

at least a third row of the plurality of rows is between the first and second rows.

7. The light-sensing apparatus of claim 1, further comprising:

a gate driver configured to sequentially apply a gate voltage to the plurality of gate lines; and

a signal output unit including a plurality of data lines extending in a column direction, the signal output unit configured to receive light-sensing signals from the light-sensing pixels and output data signals.

8. The light-sensing apparatus of claim 7, wherein

each of the data lines is connected to sources of the plurality of the switch transistors in a same column.

9. The light-sensing apparatus of claim 7, wherein

a number of the plurality of gate lines is equal to a number of pixel rows of the light-sensing pixel array, and

the gate driver is connected to at least one dummy gate line, the one dummy gate line only being connected to gates of light sensor transistors.

10. The light-sensing apparatus of claim 9, wherein

the pixel rows are sequentially ordered from a first row to a last row,

one of the first and last rows includes a plurality of the light sensor transistors, and

the dummy gate line is connected to gates of the plurality of the light sensor transistors included in the one of the first and last rows.

11. The light-sensing apparatus of claim 1, wherein the light sensor transistor includes an oxide semiconductor channel layer.

12. An optical touch screen apparatus, comprising:

a pixel array including

a plurality of display pixels in a plurality of rows and columns, each of the display pixels including a display cell and a first switch transistor configured to turn the display cell ON or OFF, and

at least one light-sensing pixel in the plurality of rows and the plurality of columns, the light-sensing pixel including a light sensor transistor configured to sense light and a second switch transistor configured to output a light-sensing signal from the light sensor transistor; and

a plurality of gate lines extending in a row direction and configured to apply a gate voltage to the display pixels and the light-sensing pixel, a gate of the light sensor transistor in a first row of the plurality of rows being connected to a gate line in a second row of the plurality of rows.

13. The optical touch screen apparatus of claim 12, further comprising:

a gate driver configured to sequentially apply a gate voltage to the plurality of gate lines;

a signal output unit including a plurality of data lines extending in a column direction, the signal output unit configured to receive light-sensing signals from the light-sensing pixels and output data signals; and

a data driver including a plurality of image data lines extending in the column direction and configured to apply image signals to the display pixels.

14. The optical touch screen apparatus of claim 12, wherein

each of the gate lines is connected to a plurality of display pixels and a plurality of the light-sensing pixels in a same row.

15. The optical touch screen apparatus of claim 12, wherein

each of the gates lines is connected to gates of a plurality of the first and second switch transistors in a same row.

16. The optical touch screen apparatus of claim 15, wherein the second switch transistor and the light sensor transistor in each of the light-sensing pixels are connected in series.

17. The optical touch screen apparatus of claim 12, wherein

the first row is immediately adjacent to the second row.

18. The optical touch screen apparatus of claim 12, wherein

at least a third row of the plurality of rows is between the first and second rows.

19. The optical touch screen apparatus of claim 12, further comprising:

at least one dummy gate line that is only connected to gates of the light sensor transistors.

20. The optical touch screen apparatus of claim 19, wherein

the pixel rows are sequentially ordered from a first row to a last row,

one of the first and last rows includes a plurality of the light sensor transistors, and

the dummy gate line is connected to gates of the plurality of the light sensor transistors included in the one of the first and last rows.

21. The optical touch screen apparatus of claim 12, wherein

the pixel array includes a plurality of first pixels including one of the display pixels and one of the light-sensing pixels and a plurality of second pixels including one of the display pixels and none of the light-sensing pixels.

22. The optical touch screen apparatus of claim 21, wherein the first pixels and the second pixels are alternated in a row direction.

23. An optical touch screen apparatus, comprising:

a pixel array including

a plurality of display pixels in a plurality of rows and columns, each of the display pixels including a display cell and a first switch transistor configured to turn the display cell ON or OFF, and

at least one light-sensing pixel in the plurality of rows and the plurality of columns, the light-sensing pixel including a light sensor transistor configured to sense light, and second and third switch transistors each configured to output a light-sensing signal from the light sensor transistor; and

a plurality of gate lines extending in a row direction and configured to apply a gate voltage to the display pixels and the light-sensing pixel, a gate of the light sensor transistor in a first row of the plurality of rows being connected to a gate line in a second row of the plurality of rows.

24. The optical touch screen apparatus of claim 23, wherein

each of the gate lines is connected to a plurality of display pixels and a plurality of the light-sensing pixels in a same row.

25. The optical touch screen apparatus of claim 23, wherein the pixel array includes

at least one first array pixel including a first display pixel of the display pixels, the second switch transistor, and the light sensor transistor;

and

at least one second array pixel including a second display pixel of the display pixels and the third switch transistor.

26. The optical touch screen apparatus of claim 25, wherein

the first array pixels and the second array pixels alternate in a row direction.

27. The optical touch screen apparatus of claim 25, wherein

gate lines corresponding to rows including the first array pixels are connected to gates of at least one of the first switch transistors and at least one of the second switch transistors, and

gate lines corresponding to rows including the second array pixels are connected to gates of at least one of the first switch transistors and at least one of the third switch transistors.

28. The optical touch screen apparatus of claim 23, wherein the second switch transistor and the third switch transistor are in different rows.

29. The optical touch screen apparatus of claim 28, wherein the second switch transistor and the third switch transistor are each connected in series with the light sensor transistor.

30. The optical touch screen apparatus of claim 29, wherein

the second row does not include one of the second and third switch transistors which are connected in series with the light sensor transistors in the first row.

31. The optical touch screen apparatus of claim 23, further comprising:

at least one dummy gate line that is only connected to one or more light sensor transistors.

32. The optical touch screen apparatus of claim 31, wherein

gates of the light sensor transistors of one of a first and a last one of the light-sensing pixels arranged in a row direction in the pixel array are connected to the dummy gate line.

33. A method of operating a light-sensing apparatus, the method comprising:

applying

a high voltage to gates of a plurality of switch transistors of light-sensing pixels in a first row of a light-sensing pixel array via a first gate line of the first row, and

a low voltage to gates of a plurality of light sensor transistors of the light-sensing pixels in the first row via a second gate line of a second row and to gates of switch transistors of light-sensing pixels in rows of the light-sensing pixel array other than the first row; and

applying

the high voltage to the gates of the plurality of light-sensor transistors in the first row via the second gate line and to gates of a plurality of switch transistors of light-sensing pixels in the second row via the second gate line, and

the low voltage to gates of switch transistors of light-sensing pixels in rows of the light-sensing pixel array other than the second row.

34. The method of claim 33, wherein the plurality of light sensor transistors include oxide semiconductor channels.

35. The method of claim 34, wherein the low voltage is a voltage between a threshold voltage of the light sensor transistors when no light is incident thereon and a threshold voltage of the light sensor transistors when light is incident thereon.

36. The method of claim 34, wherein the high voltage is greatest of a threshold voltage of the switch transistor and a voltage to reset the light sensor transistor.

37. The method of claim 33, further comprising:

applying a high voltage to gates of a plurality of switch transistors in a third row via a third gate line, the third row between the first and second rows, the plurality of switch transistors in the third row each connected to a different one of the plurality of light sensor transistors of the light-sensing pixels in the first row.

38. The method of claim 37, further comprising:

outputting light-sensing signals from the light sensor transistors during the applying a high voltage to gates of a plurality of switch transistors of light-sensing pixels in a first row; and

outputting light-sensing signals from the light sensor transistors during the applying a high voltage to gates of a plurality of switch transistors in a third row.

39. An optical touch screen pixel array, comprising:

first and second switching transistors in a first row;

a first light sensor transistor in a second row; and

a first gate line connected to the first and second switching transistors, and to the first light sensor transistor.

40. The optical touch screen pixel array of claim 39, further comprising:

third and fourth switching transistors in a third row;

a second light sensor transistor in the first row connected in series with the second switching transistor;

a second gate line connected to the third and fourth switching transistors, and to the second light sensor transistor;

a first display cell in the first row connected to the first switching transistor; and

a second display cell in the third row connected to the third switching transistor.

41. The optical touch screen pixel array of claim 40, further comprising:

a fifth switching transistor in a fourth row between the first and third rows;

a third gate line connected to the fifth switching transistor, the third gate line not connected to a gate of any light sensor transistor;

a third display cell connected to the fifth switching transistor; and

a third light sensor transistor in the third row connected in series with the fourth switching transistor.

42. The optical touch screen pixel array of claim 41, further comprising:

a sixth switching transistor in the fourth row;

wherein the third gate line is connected to the sixth switching transistor;

the sixth switching transistor is connected to the second light sensor transistor; and

the second and sixth switching transistor are connected in parallel.

43. The optical touch screen pixel array of claim 42, further comprising:

a fourth display cell in a fifth row;

a seventh switching transistor connected to the fourth display cell in the fifth row; and

a fourth gate line connected to the seventh switching transistor,

wherein no circuit element in the fifth row is connected to any element of a different row.

44. The optical touch screen pixel array of claim 39, further comprising:

a first display cell connected to the first switching transistor in the first row;

a second display cell in the second row;

a third switching transistor connected to the second display cell in the second row;

a fourth switching transistor connected in series to the first light sensor transistor in the second row;

a second gate line connected to the third and fourth switching transistors; and

a gate driver connected to the first and second gate lines, the gate driver configured to scan a frame by scanning the gate lines in a sequential order, the first gate line being prior to the second gate line in the sequential order.

45. The optical touch screen pixel array of claim 39, further comprising:

a first display cell connected to the first switching transistor in the first row;

a second display cell in the second row;

a third switching transistor connected to the second display cell in the second row;

a fourth switching transistor connected in series to the first light sensor transistor in the second row;

a second gate line connected to the third and fourth switching transistors; and

a gate driver connected to the first and second gate lines, the gate driver configured to scan a frame by scanning the gate lines in a sequential order, the second gate line being prior to the first gate line in the sequential order.

46. The optical touch screen pixel array of claim 39, further comprising:

a dummy gate line outside the pixel array, the dummy gate line configured to apply a reset voltage to a gate of at least one light sensor transistor of the pixel array.