Liquid crystal display device including image sensor and method of driving the same

• US 8,519,943 B2
• Filed: 05/11/2007
• Issued: 08/27/2013
• Est. Priority Date: 12/29/2006
• Status: Expired due to Fees

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: An, Cheung-Hwan, Jo, Yong-Won
• Primary Examiner(s): Nguyen, Chanh
• Assistant Examiner(s): Park, Sanghyuk
• Application Number:
  US11/798,299
• Publication Number:
  US 20080158120A1
• Time in Patent Office: 2,300 Days
• Field of Search: 345/104, 345173-178
• US Class Current: 345/104
• CPC Class Codes: G02F 1/1362 Active matrix addressed cells G02F1/134336, G02F1/134363 take precedence
• CPC Class Codes: H01L 27/14645 Colour imagers
• CPC Class Codes: H01L 27/14678 Contact-type imagers
• CPC Class Codes: H01L 27/14689 MOS based technologies
• CPC Class Codes: H01L 31/125 Composite devices with photosensitive elements and electroluminescent elements within one single body

Abstract

A liquid crystal display device includes a first data line and a second data line, the first and second data lines substantially parallel to one another, a first gate line, the first gate line crossing the first data line and the second data line, a display sub-pixel defined by the crossing of the first gate line and the first data line, a sensing sub-pixel defined by the crossing of the first gate line and the second data line, and a first switching element for connecting the second data line connected to one of a sensing processing unit and a ground terminal, wherein the display sub-pixel transmits light supplied from a light source in accordance to a data signal applied to the first data line, and the sensing sub-pixel senses light incident on the liquid crystal display device and generates charges corresponding to the sensed light.

Claims

1. A liquid crystal display device, comprising:

a first data line and a second data line, the first and second data lines being substantially parallel to one another;

a first gate line and a second gate line, the first and second gate lines being substantially parallel to one another;

a display sub-pixel defined by crossing the first gate and data lines, the display sub-pixel including a first switching element and a first storage capacitor, the display sub-pixel transmitting light supplied from a light source in accordance to a data signal applied to the first data line;

a sensing sub-pixel defined by crossing the second gate and data lines, the sensing sub-pixel including an image sensor, second switching element and a second storage capacitor, the sensing sub-pixel sensing light incident on the liquid crystal display device and generating charges corresponding to the sensed light;

a sensing processing unit for reading normal charges stored in the second storage capacitor;

a ground terminal for resetting abnormal charges stored in the second storage capacitor; and

a third switching element for connecting the second data to the sensing processing unit directly and disconnecting the second data line from the ground terminal in accordance with storing the normal charge in the second storage capacitor, and for connecting the second data line to the ground terminal directly and disconnecting the second data line from the sensing processing unit in accordance with storing the abnormal charge in the second storage capacitor,

wherein, when the light enters the image sensor, a photo current of the image sensor is stored in the second storage capacitor, and

wherein, when the second switching element is turned on, the charges in the second storage capacitor is read by the sensing processing unit through the second switching element and the second data line.

2. The device according to claim 1, wherein:

the first switching element is connected to the first gate and data lines; and

the second switching element is connected to the second gate and data lines.

3. The device according to claim 1, wherein:

the second switching element is connected to a common line and a power line; and

the third switching element is connected to the second data.

4. A liquid crystal display device, comprising:

a plurality of first and second data lines, the plurality of first data lines being alternatively arranged with the plurality of second data lines;

a plurality of first and second gate lines, the plurality of first gate lines being alternatively arranged with the plurality of second gate lines;

a plurality of first sub-pixels defined by crossing the plurality of first gate and data lines, the plurality of first sub-pixels being activated to display all image by selectively transmitting light irradiated from a rear side of the liquid crystal display device;

a plurality of second sub-pixels defined by crossing the plurality of second gate and data lines, the plurality of second sub-pixels being selectively activated to sense one color light irradiated onto a front side of the liquid crystal display device, the plurality of first and second sub-pixels being located alternatively with one another, each of the plurality of second sub-pixels including an image sensor, switching element, and a storage capacitor;

a sensing processing unit for reading normal charges stored in each of the plurality of second sub-pixels;

a ground terminal for resetting abnormal charges stored in each of the plurality of second sub-pixels; and

a switching element for connecting each of the plurality of second data lines to the sensing processing unit directly and disconnecting each of the plurality of second data lines from the ground terminal in accordance with storing the normal charge in the second sub-pixels, and for connecting each of the plurality of second data lines to the ground terminal directly and disconnecting each of the plurality of second data lines from the sensing processing unit in accordance with storing the abnormal charge in the second pixels,

wherein, when the light enters the image sensor, a photo current of the image sensor is stored in the storage capacitor, and

wherein, when the switching element is turned on, the charges in the storage capacitor is read by the sensing processing unit through the switching element and each of the plurality of second data line.

5. The device according to claim 4, wherein each of the plurality of first sub-pixels include a first color display sub-pixel, a second color display sub-pixel, and a third color display sub-pixel, the first, second, and third color display sub-pixels being sequentially driven.

6. The device according to claim 4, wherein each of the plurality of second sub-pixels include a first color sensing sub-pixel, a second color sensing sub-pixel, and a third color sensing sub-pixel, the first, second, and third color sensing sub-pixels sequentially generating intensity signals.

7. The device according to claim 6, wherein the sensing processing unit is selectively connected to receive the intensity signals from one of the first, second, and third color sensing sub-pixels.

8. A method of driving a liquid crystal display device including a plurality of display sub-pixels by crossing a plurality of first gate and data lines, a plurality of sensing sub-pixel by crossing a plurality of second gate and data lines, a sensing processing unit for reading normal charges stored in each of the plurality of sensing sub-pixels, a ground terminal for resetting abnormal charges stored in each of the plurality of sensing sub-pixels, and a switching element for connecting each of the plurality of second data lines to the sensing processing unit directly and disconnecting each of the plurality of second data lines from the ground terminal in accordance with storing the normal charge in the plurality of sensing sub-pixels, and for connecting each of the of second data lines to the ground terminal directly disconnecting each of the plurality of second data lines from the sensing processing unit in accordance with storing the abnormal charge in the plurality of sensing sub-pixels, the display sub-pixel including first, second, and third color display sub-pixels and wherein the sensing sub-pixel includes of first, second, and third color sensing sub-pixels, the method comprising:

in a display mode, sequentially activating the first, second, and third color display sub-pixels in a display mode; and

in a sensing mode;

sensing an object by one of the first, second, and third color sensing sub-pixels;

storing a normal sensing data in one of the first, second, and third color sensing sub-pixels; and

resetting an abnormal sensing data stored in the other two of first, second, and third color sensing sub-pixels by a scattered light of the object.

9. The method according to claim 8, wherein:

the first, second, and third color display sub-pixels correspond to red, green, and blue color display sub-pixels, respectively;

the first, second, and third color sensing sub-pixels correspond to red, green, and blue color sensing sub-pixels; and

in the sensing mode, activating one of the first, second, and third color sensing sub-pixels includes;

supplying a gate signal of a high level voltage to an n^th gate line to turn on at least three first switching elements and at least three second switching elements connected to the n^th gate line;

sequentially supplying a first display data signal to one of the red, green, and blue display sub-pixels through one of a red display data line, a green display data line, and a blue display data line; and

reading a sensing data signal in the red, green, and blue sensing sub-pixels through a red sensing data line, a green sensing data line, and a blue sensing data line, respectively.

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

in the sensing mode, supplying a second display data signal to two of the red, green, and blue display sub-pixels through two of the red, green, and blue display data lines, the second display data signal having a voltage lower than the first display data signal and one of the red, green, and blue display sub-pixels receiving one of the first and second display data signals at a time period.

11. The method according to claim 10, wherein the first and second display data signals respectively correspond to maximum and minimum transmittances of each of the red, green, and blue display sub-pixels.

12. The method according to claim 9, wherein the reading the sensing data signal includes transmitting the sensing data signal in one of the red, green, and blue sensing sub-pixels to a sensing processing unit through one of the red sensing data line, the green sensing data line, and the blue sensing data line.

13. The method according to claim 8, wherein:

the first, second, and third color display sub-pixels correspond to red, green, and blue color display sub-pixels, respectively;

the first, second, third color sensing sub-pixels correspond to red, green, and blue color sensing sub-pixels; and

in the sensing mode, activating the first, second, and third color sensing sub-pixels includes;

supplying a gate signal of a high level voltage to an n^th gate line to turn on at least three first switching elements connected to the n^th gate line;

supplying the gate signal of a high level voltage to an (n+1)^th gate line to turn on at least three second switching elements connected to the (n+1)^th gate line;

sequentially supplying a first display data signal to the red, green, and blue display sub-pixels through a red display data line, a green display data line, and a blue display data line, respectively; and

reading a sensing data signal in the red, green, and blue sensing sub-pixels through a red sensing data line, a green sensing data line, and a blue sensing data line, respectively.

14. The method according to claim 13, further comprising in the sensing mode, supplying a second display data signal to two of the red, green, and blue display sub-pixels through two of the red, green, and blue display data lines, the second display data signal having a voltage lower than the first display data signal and each of the red, green, and blue display sub-pixels receiving one of the first and second display data signals at a time period.

15. The method according to claim 14, wherein the first and second display data signals respectively correspond to maximum and minimum transmittances of each of the red, green, and blue display sub-pixels.

16. The method according to claim 13, wherein the reading the sensing data signal includes transmitting the sensing data signal in one of the red, green, and blue sensing sub-pixels to a sensing processing unit through one of the red sensing data line, the green sensing data line, and the blue sensing data line.

17. The method according to claim 8, further comprising, in the sensing mode:

during a first sub-period, activating a first color sensing sub-pixel and resetting the second color sensing sub-pixel and the third color sensing sub-pixel;

during the second sub-period, activating a second color sensing sub-pixel and resetting the first color sensing sub-pixel and the third color sensing sub-pixel; and

during the third sub-period, activating a third color sensing sub-pixel and resetting the first color sensing sub-pixel and the second color sensing sub-pixel.

18. The method according to claim 8, wherein the resetting the sensing sub-pixels includes grounding charges generated at the sensing sub-pixels.