Liquid crystal display device including sensing element

• US 20060017710A1
• Filed: 07/26/2005
• Published: 01/26/2006
• Est. Priority Date: 07/26/2004
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Joo-Hyung, Park, Jong-Woung, Uh, Kee-Han, Park, Sang-Jin
• Granted Patent: US 7,742,041 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G06F 2203/04106 Multi-sensing digitiser, i.e. digitiser using at least two different sensing technologies simultaneously or alternatively, e.g. for detecting pen and finger, for saving power or for improving position detection
• 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: G06F 3/0447 Position sensing using the local deformation of sensor cells
• CPC Class Codes: G09G 2360/148 the light being detected by light detection means within each pixel
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

A liquid crystal display includes a first panel, a second panel facing the first panel and spaced apart from the first panel, a liquid crystal layer disposed between the first panel and the second panel, a variable capacitor having a capacitance that varies by a touch and generating a control voltage that has a magnitude depending on the capacitance, and a sensing element disposed on the second panel and generating a sensing signal based on the control voltage.

Claims

1. A liquid crystal display device comprising:

a first panel;

a second panel facing the first panel and spaced apart from the first panel;

a liquid crystal layer disposed between the first panel and the second panel;

a variable capacitor having a capacitance that varies in response to a touch applied on one of the first and second panels, the variable capacitor generating a control voltage that has a magnitude depending on the capacitance; and

a sensing element disposed on the second panel and generating a sensing signal based on the control voltage.

2. The liquid crystal display device of claim 1, wherein the touch comprises pressure.

3. The liquid crystal display device of claim 1, wherein the variable capacitor comprises a first capacitor electrode disposed on the first panel and a second capacitor electrode disposed on the second panel.

4. The liquid crystal display device of claim 3, wherein a distance between the first capacitor electrode and the second capacitor electrode varies by the touch to vary the capacitance of the variable capacitor.

5. The liquid crystal display device of claim 4, wherein the sensing element generates an electrical signal included in the sensing signal in response to light incident into the liquid crystal display device.

6. The liquid crystal display device of claim 5, wherein the light incident into the liquid crystal display device is varied by the touch.

7. The liquid crystal display device of claim 6, wherein the sensing element comprises amorphous silicon or polysilicon.

8. The liquid crystal display device of claim 4, wherein the first capacitor electrode is supplied with a predetermined voltage having a magnitude swinging between two values.

9. The liquid crystal display device of claim 4, wherein the sensing element comprises a control terminal, an input terminal, and an output terminal, and the control terminal of the sensing element is connected to the second capacitor electrode.

10. The liquid crystal display device of claim 9, further comprising a first switching element connected to the output terminal of the sensing element and selectively outputting the sensing signal.

11. The liquid crystal display device of claim 10, further comprising a sensor capacitor disposed between the control terminal and the output terminal of the sensing element.

12. A liquid crystal display device comprising:

a plurality of image scanning lines;

a plurality of image data lines intersecting the image scanning lines;

a plurality of sensor data lines intersecting the image scanning lines, the sensor data lines being separated from the image scanning lines and the image data lines; and

a plurality of pixels, each pixel including a display circuit and a sensing circuit,

wherein the display circuit comprises a liquid crystal capacitor and a first switching element connected to the liquid crystal capacitor, one of the image scanning lines, and one of the image data lines, and the sensing circuit comprises a variable capacitor having a capacitance that varies in response to a touch applied on a display panel of the liquid crystal display device, a sensing element connected to the variable capacitor, and a second switching element connected to the sensing element and one of the sensor data lines.

13. The liquid crystal display device of claim 12, wherein the variable capacitor comprises first and second electrodes facing each other, the liquid crystal capacitor comprises third and fourth electrodes facing each other, and the second electrode and the fourth electrode form a continuous plane.

14. The liquid crystal display device of claim 13, wherein a distance between the first electrode and the second electrode is smaller than a distance between the third electrode and the fourth electrode.

15. The liquid crystal display device of claim 13, wherein the variable capacitor comprises a first liquid crystal dielectric disposed between the first electrode and the second electrode, and the liquid crystal capacitor comprises a second liquid crystal dielectric disposed between the third electrode and the fourth electrode.

16. The liquid crystal display device of claim 15, wherein the first liquid crystal dielectric and the second liquid crystal dielectric communicate with each other and the first liquid crystal dielectric is thinner than the second liquid crystal dielectric.

17. The liquid crystal display device of claim 12, wherein each of the second switching element and the sensing element includes a control terminal, an input terminal, and an output terminal, the input terminal of the second switching element is coupled with the output terminal of the sensing element, the output terminal of the second switching element is connected to one of the sensing data lines, and the control terminal of the sensing element is coupled with the variable capacitor.

18. The liquid crystal display device of claim 17, further comprising a plurality of sensor control terminal lines, each of the sensor control terminal lines connected to the control terminal of corresponding one of the second switching elements of a group of pixels.

19. The liquid crystal display device of claim 17, further comprising a plurality of sensing scanning lines each connected to the control terminal of corresponding one of the second switching elements.

20. The liquid crystal display device of claim 19, wherein the input terminal of each sensing element is supplied with a predetermined voltage.

21. The liquid crystal display device of claim 19, wherein the input terminal of the sensing element is connected to the one of the image scanning lines.

22. The liquid crystal display device of claim 19, further comprising:

an image scanning driver generating image scanning signals to be applied to the image scanning lines;

an image data driver applying image data signals to the image data lines;

a sensor scanning driver generating sensor scanning signals to be applied to the sensor scanning lines;

a sensing signal processor receiving and processing sensing signals from the sensing elements; and

a signal controller providing control signals to the image scanning driver, the image data driver, the sensing scanning driver, and the sensing signal processor.

23. The liquid crystal display device of claim 17, wherein the control terminal of the second switching element is connected to one of the image scanning lines.

24. The liquid crystal display device of claim 23, wherein the input terminal of the sensing element is connected to the one of the image scanning lines.

25. The liquid crystal display device of claim 23, wherein the input terminal of each sensing element is supplied with a predetermined voltage.

26. The liquid crystal display device of claim 23, further comprising:

an image scanning driver generating image scanning signals to be applied to the image scanning lines;

an image data driver applying image data signals to the image data lines;

a sensing signal processor receiving and processing sensing signals from the sensing elements; and

a signal controller providing control signals to the image scanning driver, the image data driver, and the sensing signal processor.

27. A liquid crystal display device comprising:

a first substrate;

a common electrode formed on the first substrate;

a second substrate facing the first substrate and spaced apart from the first substrate;

an image scanning line disposed on the second substrate;

an image data line disposed on the second substrate and intersecting the image scanning line;

a first thin film transistor connected to the image scanning line and the image data line;

a pixel electrode connected to the first thin film transistor and facing the common electrode;

a sensing electrode disposed on the second substrate and facing the common electrode;

a second thin film transistor having a control electrode connected to the sensing electrode; and

a liquid crystal layer disposed between the first substrate and the second substrate,

wherein the sensing electrode and the control electrode of the second thin film transistor are floating.

28. The liquid crystal display device of claim 27, further comprising a rising disposed between the first substrate and the common electrode and facing the sensing electrode.

29. The liquid crystal display device of claim 28, wherein the liquid crystal layer on the rising has a thickness from about 0.01 microns to about 2.0 microns.

30. The liquid crystal display device of claim 28, further comprising an insulating layer disposed between the second thin film transistor and the sensing electrode, and a contact hole connecting the sensing electrode and the control electrode of the second thin film transistor.

31. The liquid crystal display device of claim 30, wherein the sensing electrode and the pixel electrode comprise the same layer and a distance between the sensing electrode and the pixel electrode is larger than about 3 microns.

32. The liquid crystal display device of claim 28, further comprising a third thin film transistor having an input electrode connected to an output electrode of the second thin film transistor.

33. The liquid crystal display device of claim 28, further comprising a spacer propping the first substrate and the second substrate.

34. The liquid crystal display device of claim 28, wherein the pixel electrode comprises a transparent electrode and a reflective electrode having an opening exposing the second thin film transistor.