SIMPLIFIED LIGHT SENSING CIRCUIT, LIGHT SENSING APPARATUS INCLUDING THE LIGHT SENSING CIRCUIT, METHOD OF DRIVING THE LIGHT SENSING APPARATUS, AND IMAGE ACQUISITION APPARATUS AND OPTICAL TOUCH SCREEN APPARATUS INCLUDING THE LIGHT SENSING APPARATUS

• US 20120274608A1
• Filed: 07/10/2012
• Published: 11/01/2012
• Est. Priority Date: 04/22/2010
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Young, Song, I-hun, Ahn, Seung-eon, Jeon, Sang-hun, Kim, Chang-jung, Park, Sung-ho
• Granted Patent: US 9,891,102 B2
• Time in Patent Office: Days
• US Class Current: 345/175
• CPC Class Codes: G01J 1/44 Electric circuits for command of an exposure part G03B7/02
• CPC Class Codes: G06F 3/0386 for light pen
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/042 by opto-electronic means
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence
• CPC Class Codes: H01L 27/1225 with semiconductor materials not belonging to the group IV of the periodic table, e.g. InGaZnO
• CPC Class Codes: H01L 27/14609 Pixel-elements with integrated switching, control, storage or amplification elements scanning details of imagers (circuitry of solid-state image sensors H04N25/00); circuitry of imagers H04N25/70
• CPC Class Codes: H01L 27/14681 Bipolar transistor imagers
• CPC Class Codes: H01L 31/1136 the device being a metal-insulator-semiconductor field-effect transistor
• CPC Class Codes: H04N 25/77 Pixel circuitry, e.g. memories, A/D converters, pixel amplifiers, shared circuits or shared components

Abstract

In a simplified light sensing circuit, a light sensing apparatus including the light sensing circuit, a method of driving the light sensing apparatus, and an image acquisition apparatus and optical touch screen apparatus including the light sensing apparatus, the light sensing circuit includes an oxide semiconductor transistor including a channel layer including an oxide semiconductor material, for each pixel. The oxide semiconductor transistor is configured to operate as a light sensing device that senses light and a switch that outputs light sensing data.

Claims

1. A light sensing circuit, comprising:

an oxide semiconductor transistor including a channel layer including an oxide semiconductor material,

wherein the oxide semiconductor transistor is configured to operate as a light sensing device that senses light and a switch that outputs light sensing data.

2. The light sensing circuit of claim 1, further comprising:

a gate line connected to a gate of the oxide semiconductor transistor and configured to provide a gate voltage;

a drive voltage line connected to a drain of the oxide semiconductor transistor and configured to provide a drive voltage; and

a data line connected to a source of the oxide semiconductor transistor and configured to provide data.

3. The light sensing circuit of claim 2, further comprising:

a gate driver configured to provide the gate voltage to the gate of the oxide semiconductor transistor via the gate line,

wherein the gate driver is configured such that the gate voltage is any one of a first voltage that is lower than a first threshold voltage, a second voltage that is between the first threshold voltage and a second threshold voltage, and a third voltage that is positive, the first threshold voltage being a threshold voltage of the oxide semiconductor transistor when light is incident on the oxide semiconductor transistor, the second threshold voltage being a threshold voltage of the oxide semiconductor transistor when light not incident on the oxide semiconductor transistor.

4. The light sensing circuit of claim 1, further comprising:

a gate line connected to both of a gate and a drain of the oxide semiconductor transistor and configured to provide a gate voltage; and

a data line connected to a source of the oxide semiconductor transistor and configured to provide data.

5. The light sensing circuit of claim 4, further comprising:

a gate driver configured to provide the gate voltage to the gate of the oxide semiconductor transistor via the gate line,

wherein the gate driver is configured such that the gate voltage is any one of a first voltage that is lower than a first threshold voltage, a second voltage that is between the first threshold voltage and a second threshold voltage, and a third voltage that is positive, the first threshold voltage being a threshold voltage of the oxide semiconductor transistor when light is incident on the oxide semiconductor transistor, the second threshold voltage being a threshold voltage of the oxide semiconductor transistor when light not incident on the oxide semiconductor transistor.

6. The light sensing circuit of claim 1, wherein the oxide semiconductor transistor further includes a substrate;

a gate on at least a portion of the substrate;

a gate insulation film on the substrate and the gate to cover at least the gate;

a source and a drain on opposite sides of the channel layer; and

a transparent insulation layer covering the source, the drain, and the channel layer,

wherein the channel layer is on the gate insulation film and facing the gate.

7. The light sensing circuit of claim 6, wherein the oxide semiconductor transistor further includes

a first conductive plug that passes through the transparent insulation layer and is electrically connected to the source;

a first contact on the transparent insulation that electrically contacts the first conductive plug;

a second conductive plug that passes through the transparent insulation layer and is electrically connected to the drain; and

a second contact on the transparent insulation layer that electrically contacts the second conductive plug.

8. The light sensing circuit of claim 1, wherein the oxide semiconductor transistor comprises:

a substrate;

a gate insulation film on at least a central portion of the channel layer;

a gate on the gate insulation film that faces the channel layer;

a source and a drain on the channel layer at opposite sides of the gate, the source and drain each being separate from the gate; and

a transparent insulation layer covering the gate, the source, and the drain,

wherein the channel layer is on the substrate.

9. The light sensing circuit of claim 1, wherein the oxide semiconductor material includes one or more of ZnO, InO, SnO, InZnO, ZnSnO, or InSnO, or a material formed by adding at least one of Hf, Zr, Ti, Ta, Ga, Nb, V, Al, and Sn to one of ZnO, InO, SnO, InZnO, ZnSnO, or InSnO.

22. An image acquisition apparatus, comprising:

the light sensing circuit of claim 1 in a pixel.

24. An optical touch screen apparatus, comprising:

a display apparatus configured to display an image;

an optical touch panel attached on a screen of the display apparatus, the optical touch panel including the light sensing circuit of claim 1 in a pixel; and

a light source apparatus configured to provide an optical signal to the optical touch panel.

10. 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; and

a gate driver including a plurality of gate lines in a row direction, the gate driver being configured to provide a gate voltage and a reset signal to each of the plurality of light sensing pixels via the plurality of gate lines,

wherein each of the plurality of light sensing pixels includes an oxide semiconductor transistor configured to operate as a both a light sensing device that senses light and a switch that outputs light sensing data.

11. The light sensing apparatus of claim 10, wherein the gate driver is configured to apply the gate voltage to the oxide semiconductor transistors sequentially in the row direction, and to apply the reset signal to all of the oxide semiconductor transistors at a time after applying the gate voltage to the oxide semiconductor transistors sequentially in the row direction.

12. The light sensing apparatus of claim 10, wherein the gate driver is configured to provide each oxide semiconductor transistor with a first voltage that is lower than a first threshold voltage, a second voltage that is between the first threshold voltage and a second threshold voltage, and a third voltage that is positive, the first threshold voltage being a threshold voltage of the oxide semiconductor transistor when light is incident on the oxide semiconductor transistor, the second threshold voltage being a threshold voltage of the oxide semiconductor transistor when light not incident on the oxide semiconductor transistor.

13. The light sensing apparatus of claim 12, wherein the gate driver is configured to provide the gate voltage to each oxide semiconductor transistor in order of the first voltage, the second voltage, the first voltage, and the third voltage, and the third voltage is the reset signal to reset the oxide semiconductor transistor.

14. The light sensing apparatus of claim 10, wherein each gate line is connected to light sensing pixels, from among the plurality of light sensing pixels, that are in the same row.

15. The light sensing apparatus of claim 14, wherein gates of the oxide semiconductor transistors of the plurality of light sensing pixels in a row are connected to the gate line of the same row.

16. The light sensing apparatus of claim 10, further comprising:

a signal output unit that includes a plurality of data lines in a column direction, the signal output unit being configured to receive a light sensing signal from each of the plurality of light sensing pixels and output a data signal.

17. The light sensing apparatus of claim 16, wherein sources of the oxide semiconductor transistors of the plurality of light sensing pixels in a column are connected to the data line of the same column.

18. The light sensing apparatus of claim 16, wherein the signal output unit includes

an A/D converter configured to convert analog signals output from the plurality of light sensing pixels into digital signals;

a buffer configured to temporarily store the digital signals; and

a column scanner configured to select an output from one of the plurality of light sensing pixels in a column.

19. The light sensing apparatus of claim 10, wherein the oxide semiconductor transistor comprises:

a substrate;

a gate on at least a portion of the substrate;

a gate insulation film on the substrate and the gate that covers at least the gate;

a channel layer on the gate insulation film and facing the gate;

a source and a drain on opposite sides of the channel layer, respectively; and

a transparent insulation layer covering the source, the drain, and the channel layer,

wherein the channel layer is formed of an oxide semiconductor material.

20. The light sensing apparatus of claim 19, wherein the oxide semiconductor material includes one or more of ZnO, InO, SnO, InZnO, ZnSnO, or InSnO, or a material formed by adding at least one of Hf, Zr, Ti, Ta, Ga, Nb, V, Al, and Sn to one of ZnO, InO, SnO, InZnO, ZnSnO, or InSnO.

21. The light sensing apparatus of claim 10, wherein the oxide semiconductor transistor comprises:

a substrate;

a channel layer on the substrate;

a gate insulation film on at least a central portion of the channel layer;

a gate on the gate insulation film that faces the channel layer;

a source and a drain on the channel layer at opposite sides of the gate, the source and drain each being separate from the gate; and

a transparent insulation layer covering the gate, the source, and the drain,

wherein the channel layer is formed of an oxide semiconductor material.

23. An image acquisition apparatus, comprising:

the light sensing apparatus of claim 10.

25. An optical touch screen apparatus, comprising:

a display apparatus configured to display an image;

an optical touch panel attached on a screen of the display apparatus, the optical touch panel including the light sensing apparatus of claim 10; and

a light source apparatus configured to provide an optical signal to the optical touch panel.

26. A method of driving a light sensing apparatus, the method comprising:

sequentially applying a negative first voltage, a negative second voltage that is higher than the first voltage, and a positive third voltage to a gate of an oxide semiconductor transistor that operates as both a light sensing device sensing light and a switch outputting light sensing data.

27. The method of claim 26, wherein the first voltage is lower than a first threshold voltage, and the second voltage is between the first threshold voltage and a second threshold voltage, the first threshold voltage being a threshold voltage of the oxide semiconductor transistor when light is incident on the oxide semiconductor transistor, the second threshold voltage being a threshold voltage of the oxide semiconductor transistor when light not incident on the oxide semiconductor transistor.

28. The method of claim 27, wherein the third voltage is a reset signal that resets the oxide semiconductor transistor.

29. The method of claim 27, further comprising:

measuring current flowing between a drain and a source of the oxide semiconductor transistor during the application of the second voltage to a gate of the oxide semiconductor transistor.

30. A method of driving a light sensing apparatus, the light sensing apparatus comprising a plurality of light sensing pixels in a plurality of rows and a plurality of columns, each of the light sensing pixels including an oxide semiconductor transistor that operates as both a light sensing device sensing light and a switch outputting light sensing data, the method comprising:

applying a negative second voltage to gates of the oxide semiconductor transistors of the plurality of light sensing pixels in a row from among the plurality of rows, and a negative first voltage that is lower than the second voltage to the gates of the oxide semiconductor transistors in other rows from among the plurality of rows;

sequentially applying the second voltage to the gates of the oxide semiconductor transistors of the plurality of light sensing pixels in a next row from among the plurality or rows, and applying the first voltage to the gates of the oxide semiconductor transistors of the plurality of light sensing pixels in rows other than the next row from among the plurality of rows; and

simultaneously applying a positive third voltage to the gates of the oxide semiconductor transistors of the plurality of the light sensing pixels in all the rows, after the sequential application of the second voltage to all rows is completed.

31. The method of claim 30, wherein the first voltage is lower than a first threshold voltage, and the second voltage is between the first threshold voltage and a second threshold voltage, the first threshold voltage being a threshold voltage of the oxide semiconductor transistor when light is incident on the oxide semiconductor transistor, the second threshold voltage being a threshold voltage of the oxide semiconductor transistor when light not incident on the oxide semiconductor transistor.

32. The method of claim 31, wherein the third voltage is a reset signal that resets the oxide semiconductor transistor.

33. The method of claim 31, further comprising:

measuring current flowing between a drain and a source of the oxide semiconductor transistor during the application of the second voltage to a gate of the oxide semiconductor transistor.