Position sensing liquid crystal display and method for fabricating the same

• US 20010020987A1
• Filed: 05/16/2001
• Published: 09/13/2001
• Est. Priority Date: 10/31/1997
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: Sung Joon Bae, Young Soo Ahn
• Inventors: Bae, Sung Joon, Ahn, Young Soo
• Granted Patent: US 6,388,729 B2
• Time in Patent Office: Days
• US Class Current: 349/12
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/133512 Light shielding layers, e.g. black matrix G02F1/136209 takes precedence
• CPC Class Codes: G02F 1/1339 Gaskets; Spacers; Sealing of cells
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0444 using a single conductive element covering the whole sensing surface, e.g. by sensing the electrical current flowing at the corners

Abstract

A position sensing liquid crystal display includes a liquid crystal display panel having a first substrate and a second substrate bonded together, and a position sensing digitizer formed as an integral unit on a first or rear surface of at least one of the substrates, whereby minimizing a display panel thickness and allowing an accurate position sensing.

Claims

1. A liquid crystal display panel, comprising:

a first substrate having front and rear surfaces;

a second substrate having front and rear surfaces, the front surface of the second substrate including a plurality of pixel electrodes and abutting against the rear surface of the first substrate; and

a digitizer having intersecting grids fabricated on at least one of the front and rear surfaces of the first and second substrates.

2. A liquid crystal display panel of

claim 1

, wherein the rear surface of the first substrate includes a black matrix layer having intersecting grids at a predetermined interval.

3. A liquid crystal display panel of

claim 2

, wherein the digitizer is fabricated on the front surface of the first substrate, the intersecting grids of the digitizer being substantially aligned with the intersecting grids of the black matrix layer.

4. A liquid crystal display panel of

claim 3

, wherein the intersecting grids of the digitizer are made of a conductive material.

5. A liquid crystal display panel of

claim 4

, wherein the conductive material is one of metal and Indium Tin Oxide.

6. A liquid crystal display panel of

claim 2

, wherein the intersecting grids of the black matrix layer are the intersecting grids of the digitizer, wherein the intersecting grids of the black matrix layer are fabricated with a conductive material.

7. A liquid crystal display panel of

claim 2

, wherein the digitizer is fabricated on the rear surface of the second substrate, the intersecting grids of the digitizer being substantially aligned with the intersecting grids of the black matrix layer.

8. A liquid crystal display panel of

claim 1

, further including input signal portions fabricated in the vicinity of four corners of the digitizer, the input signal portions providing a position signal to the intersecting grids of the digitizer for detecting a stylus position.

9. A liquid crystal display panel of

claim 1

, further including input signal portions fabricated substantially in the middle of each side of the digitizer, the input signal portions providing a position signal to the intersecting grids of the digitizer for detecting a stylus position.

10. A liquid crystal display panel of

claim 8

, further including compensating resistors connected between the input signal portions and the intersecting grids of the digitizer, wherein the compensating resistors formed near the input signal portions have a higher resistivity than the compensating resistors formed farther away from the input signal portions to provide substantially equal potential to the intersecting grids of the digitizer.

11. A liquid crystal display panel of

claim 9

, further including compensating resistors connected between the input signal portions and the intersecting grids of the digitizer, wherein the compensating resistors formed near the input signal portions have a higher resistivity than the compensating resistors formed farther away from the input signal portions to provide substantially equal potential to the intersecting grids of the digitizer.

12. A liquid crystal display panel of

claim 10

, further including at least one equipotential line connected between the input signal portions and the compensating resistors, wherein the equipotential line has a lower resistivity than the compensating resistors.

13. A liquid crystal display panel of

claim 11

, further including at least one equipotential line connected between the input signal portions and the compensating resistors, wherein the equipotential line has a lower resistivity than the compensating resistors.

14. A liquid crystal display panel of

claim 9

, wherein the compensating resistors include a tree shape of repetitive sequence of layers of:

primary interconnections between adjacent grids,

secondary interconnections between adjacent primary interconnections, and

tertiary interconnections between adjacent secondary interconnections.

15. A display device using a liquid crystal display panel, comprising:

a controller that controls displayed images of the liquid crystal display panel;

a first substrate having front and rear surfaces;

a second substrate having front and rear surfaces, the front surface of the second substrate including a plurality of pixel electrodes and abutting against the rear surface of the first substrate; and

a digitizer having intersecting grids fabricated on at least one of the front and rear surfaces of the first and second substrates.

16. A display device of

claim 15

, wherein the rear surface of the first substrate includes a black matrix layer having intersecting grids at a predetermined interval.

17. A display device of

claim 16

, wherein the digitizer is fabricated on the front surface of the first substrate, the intersecting grids of the digitizer being substantially aligned with the intersecting grids of the black matrix layer.

18. A liquid crystal display panel of

claim 17

, wherein the intersecting grids of the digitizer are made of a conductive material.

19. A liquid crystal display panel of

claim 18

, wherein the conductive material is one of metal and Indium Tin Oxide.

20. A liquid crystal display panel of

claim 16

, wherein the intersecting grids of the black matrix layer are the intersecting grids of the digitizer, wherein the intersecting grids of the black matrix layer are fabricated with a conductive material.

21. A liquid crystal display panel of

claim 16

, wherein the digitizer is fabricated on the rear surface of the second substrate, the intersecting grids of the digitizer being substantially aligned with the intersecting grids of the black matrix layer.

22. A liquid crystal display panel of

claim 15

, further including input signal portions fabricated in the vicinity of four corners of the digitizer, the input signal portions providing a position signal to the intersecting grids of the digitizer for detecting a stylus position.

23. A liquid crystal display panel of

claim 15

, further including input signal portions fabricated substantially in the middle of each side of the digitizer, the input signal portions providing a position signal to the intersecting grids of the digitizer for detecting a stylus position.

24. A liquid crystal display panel of

claim 22

, further including compensating resistors connected between the input signal portions and the intersecting grids of the digitizer, wherein the compensating resistors formed near the input signal portions have higher resistivity and the compensating resistors formed farther away from the input signal portions to provide substantially equal potential to the intersecting grids of the digitizer.

25. A liquid crystal display panel of

claim 23

, further including compensating resistors connected between the input signal portions and the intersecting grids of the digitizer, wherein the compensating resistors formed near the input signal portions have higher resistivity and the compensating resistors formed farther away from the input signal portions to provide substantially equal potential to the intersecting grids of the digitizer.

26. A liquid crystal display panel of

claim 24

, further including at least one equipotential line connected between the input signal portions and the compensating resistors, wherein the equipotential line has lower resistivity than the compensating resistors.

27. A liquid crystal display panel of

claim 25

, further including at least one equipotential line connected between the input signal portions and the compensating resistors, wherein the equipotential line has lower resistivity than the compensating resistors.

28. A method for fabricating a liquid crystal display panel having a digitizer, comprising the steps of:

providing a first substrate having front and rear surfaces;

providing a second substrate having front and rear surfaces, wherein the second substrate has a first display region in the front surface;

forming a plurality of pixel electrodes in the first display region of the front surface of the second substrate;

securing the front surface of the second substrate to the rear surface of the first substrate; and

fabricating intersecting grids of the digitizer on at least one of the front and rear surfaces of the first and second substrates.

29. A method of

claim 28

, wherein before securing the front surface of the second substrate to the rear surface of the first substrate,

surrounding the first display region with a sealing material to define a first surrounded region;

and

surrounding the first surrounded region with the sealing material, wherein when the first and second substrates are secured together, the sealing material surrounding the first surrounded region substantially prohibits the intrusion of a foreign substance.

30. A method of

claim 28

, wherein before securing the front surface of the second substrate to the rear surface of the first substrate,

providing the second substrate to define a second display region;

forming pixel electrodes in the second display region of the second substrate;

surrounding the first display region with a sealing material to define a first surrounded region;

surrounding the second display region with the sealing material to define the first surrounded region;

surrounding the first and second surrounded regions with the sealing material, wherein when the first and second substrates are secured together, the sealing material surrounding the first and second surrounded regions substantially prohibits the intrusion of a foreign substance.

31. A method of

claim 29

, wherein the intersecting grids of the digitizer are fabricated on at least one of the front and rear surfaces of the first and second substrates and in the first display region.

32. A method of

claim 30

, wherein the intersecting grids of the digitizer are fabricated on at least one of the front and rear surfaces of the first and second substrates and in the first display region and the intersecting grids of a second digitizer is fabricated in the second display region.

33. A method of

claim 32

, wherein the first and second substrates are scribed to separate the first display region from the second display region, each one of the first and second display regions having the digitizer.

34. A method of

claim 28

, wherein the digitizer is formed of a conductive material.

35. A method of

claim 34

, wherein the digitizer is formed one of Indium Tin Oxide and metal.

36. A liquid crystal display panel formed by the method of

claim 28

.