Light sensing circuit, and remote optical touch panel and image acquisition apparatus including the light sensing circuit

• US 20110261017A1
• Filed: 12/17/2010
• Published: 10/27/2011
• Est. Priority Date: 04/22/2010
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Song, I-hun, Park, Sung-ho, Kim, Chang-jung, Jeon, Sang-hun, Ahn, Seung-eon
• Granted Patent: US 8,970,553 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 3/03542 Light pens for emitting or receiving light
• CPC Class Codes: G06F 3/03545 Pens or stylus
• 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 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence
• CPC Class Codes: G09G 3/3696 Generation of voltages supplied to electrode drivers
• 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

Example embodiments are directed to light sensing circuits having a relatively simpler structure by using light-sensitive oxide semiconductor transistors as light sensing devices, and remote optical touch panels and image acquisition apparatuses, each including the light sensing circuits. The light sensing circuit includes a light-sensitive oxide semiconductor transistor in each pixel, wherein the light-sensitive oxide semiconductor transistor is configured as a light sensing device, and a driving circuit that outputs data. The light sensing circuit may have a relatively simple circuit structure including a plurality of transistors in one pixel. As a result, the structure and operation of the light sensing circuit may be simplified.

Claims

1. A light sensing circuit, comprising:

a light-sensitive oxide semiconductor transistor including a channel layer of a light-sensitive oxide semiconductor,

wherein the light-sensitive oxide semiconductor transistor is configured as a light sensing device that senses light and as a driving circuit that outputs data in response to the sensed light.

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

a row selection line supplying a row selection signal to a gate of the light-sensitive oxide semiconductor transistor;

a driving voltage line supplying a driving voltage to a drain of the light-sensitive oxide semiconductor transistor; and

a data line connected to a source of the light-sensitive oxide semiconductor transistor and outputting data.

3. The light sensing circuit of claim 2, wherein

the row selection signal supplied to the gate of the light-sensitive oxide semiconductor transistor through the row selection line is one of a group consisting of a first voltage signal having a voltage lower than a first threshold voltage of the light-sensitive oxide semiconductor transistor and a second voltage signal having a voltage between the first threshold voltage of the light-sensitive oxide semiconductor transistor and a second threshold voltage, and

the first threshold voltage is a threshold voltage of the light-sensitive oxide semiconductor transistor when light is incident thereon and the second threshold voltage is a threshold voltage of the light-sensitive oxide semiconductor transistor when light is not incident thereon.

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

a row selection line supplying a row selection signal to a gate and a drain of the light-sensitive oxide semiconductor transistor; and

a data line connected to a source of the light-sensitive oxide semiconductor transistor and outputting data.

5. The light sensing circuit of claim 4, wherein

the row selection signal supplied to the gate of the light-sensitive oxide semiconductor transistor through the row selection line is one of a group consisting of a first voltage signal having a voltage lower than a first threshold voltage of the light-sensitive oxide semiconductor transistor and a second voltage signal having a voltage between the first threshold voltage of the light-sensitive oxide semiconductor transistor and a second threshold voltage, and

the first threshold voltage is a threshold voltage of the light-sensitive oxide semiconductor transistor when light is incident therein and the second threshold voltage is a threshold voltage of the light-sensitive oxide semiconductor transistor when light is incident thereon.

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

a substrate;

an insulating layer on the substrate;

a gate on at least a portion of the insulating layer;

a gate insulating film on the insulating layer and the gate, the gate insulating film surrounding the gate;

the channel layer on the gate insulating film;

a source and a drain at least partially overlapping the sides of the channel layer; and

a transparent insulating layer covering at least one of the source, the drain, and the channel layer.

7. The light sensing circuit of claim 6, wherein the light-sensitive oxide semiconductor transistor further comprises:

a first conductive plug electrically connected to the source through the transparent insulating layer;

a first contact on the transparent insulating layer and electrically connected to the first conductive plug;

a second conductive plug electrically connected to the drain through the transparent insulating layer; and

a second contact on the transparent insulating layer and electrically connected to the second conductive plug.

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

a substrate;

the channel layer on the substrate;

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

a gate on the gate insulating film;

a source and a drain on the channel layer and distant from the sides of the gate; and

a transparent insulating layer covering at least one of the gate, the source, and the drain.

9. The light sensing circuit of claim 8, wherein the light-sensitive oxide semiconductor transistor further comprises:

a first conductive plug electrically connected to the source through the transparent insulating layer;

a first contact on the transparent insulating layer and electrically connected to the first conductive plug;

a second conductive plug electrically connected to the drain through the transparent insulating layer; and

a second contact on the transparent insulating layer and electrically connected to the second conductive plug.

10. The light sensing circuit of claim 1, wherein the light-sensitive oxide semiconductor comprises InZnO (IZO), GaInZnO (Gallium Indium Zinc Oxide (GIZO)), or ZnO in which at least one of In and Hf is contained, as the channel layer.

11. An image acquisition apparatus, comprising the light sensing circuit of claim 1 in at least one pixel of the image acquisition apparatus.

12. A remote optical touch panel, comprising:

a light sensing panel including a plurality of light sensing pixels configured to sense incident light;

a row scanner configured to selectively provide a first voltage or a second voltage different from the first voltage to at least one light sensing pixel of the light sensing panel through a row selection line;

an analog-to-digital (A/D) converter configured to convert analog signals output from the light sensing panel into digital signals; and

a column scanner configured to select an output from at least one light sensing pixel of the plurality of the light sensing pixel in a desired column,

wherein at least one of the light sensing pixels includes the light sensing circuit of claim 1.

13. The remote optical touch panel of claim 12, wherein the light sensing panel comprises a plurality of row selection lines in a row direction, and a plurality of driving voltage lines and a plurality of data lines each in a column direction.

14. The remote optical touch panel of claim 13, wherein the plurality of row selection lines are connected to the row scanner.

15. The remote optical touch panel of claim 13, wherein the light sensing panel further comprises a bias transistor at an end of each data line.

16. The remote optical touch panel of claim 13, wherein

the row scanner selectively supplies a first voltage or a second voltage to the plurality of row selection lines, wherein the first voltage is lower than a first threshold voltage of the light-sensitive oxide semiconductor transistor, the second voltage is between a first threshold voltage and a second threshold voltage of the light-sensitive oxide semiconductor transistor, and

the first threshold voltage is a threshold voltage of the light-sensitive oxide semiconductor transistor when light is incident thereon, and the second threshold voltage is a threshold voltage of the light-sensitive oxide semiconductor transistor when light is not incident thereon.

17. The remote optical touch panel of claim 16, wherein the row scanner supplies the second voltage to only one selected row selection line and provides the first voltage to the remaining row selection lines.

18. The remote optical touch panel of claim of claim 12, further comprising a buffer configured to temporarily store digital output signals from the A/D converter.

19. An optical touch screen device, comprising:

the remote optical touch panel of claim 12;

a display device displaying an image; and

a light source providing an optical signal incident on the remote optical touch panel.