DISPLAY DEVICE AND DRIVING METHOD THEREOF

• US 20080117181A1
• Filed: 10/30/2007
• Published: 05/22/2008
• Est. Priority Date: 11/21/2006
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Lee, Joo-Hyung, PARK, Jong-Woung, Uh, Kee-Han, Cha, Young-Ok
• Granted Patent: US 8,547,338 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0447 Position sensing using the local deformation of sensor cells

Abstract

A display panel includes a plurality of pixels; a plurality of detection units formed in row and column directions that generate an element output signal when the display panel is touched; a detection signal processor that generates detection data based on the element output signal; and a touch determination unit that classifies the detection data in a row or column direction, that converts a row or column coordinate of a touch position or sustains a previous coordinate by comparing a reference value of each direction with the detection data, and that determines whether the touch has occurred according to the conversion number of the row or column coordinate. When the screen is continuously touched along a row or column direction, the touch or lack thereof and its position can be accurately determined by using the previous touch position information as current touch position information.

Claims

1. A display device comprising:

a display panel that comprises a plurality of pixels;

a plurality of detection units formed in row and column directions in the display panel that generate an output signal based on a touch to the display panel;

a detection signal processor that generates detection data based on the element output signal; and

a touch determination unit that classifies the detection data in row and column directions, that changes the row or column coordinate of the touch position or sustains a previous coordinate by comparing a reference value of each direction with the detection data, and that determines whether the touch has occurred according to the changed row or column coordinate.

2. The display device of claim 1, wherein the touch determination unit compares a representative value of a plurality of detection data of the row direction with the reference value;

and

compares a representative value of a plurality of detection data of the row direction with the reference value.

3. The display device of claim 2, wherein the representative value is the largest value of the plurality of detection data.

4. The display device of claim 2 or 3, wherein the touch determination unit determines a coordinate of the representative value as a touch position if the representative value is greater than the reference value;

and

sustains a previous touch position if the representative value is smaller than or equal to the reference value.

5. The display device of claim 4, wherein the touch determination unit determines that the touch has occurred if both of the row and column coordinates are changed.

6. The display device of claim 5, wherein the touch determination unit sustains a previous touch state if one of the row and column coordinates is changed.

7. The display device of claim 6, wherein the touch determination unit determines that the touch has not occurred if both of the row and column coordinates are not changed.

8. The display device of claim 1, wherein the touch determination unit further comprises a register for storing a plurality of flag values.

9. The display device of claim 8, wherein the register stores a touch position flag and a touch state flag.

10. The display device of claim 1, wherein the detection unit comprises:

a variable capacitor wherein liquid crystal is the dielectric material whose capacitance changes according to the pressure; and

a reference capacitor that is connected in series with the variable capacitor.

11. The display device of claim 1, wherein the touch determination unit comprises hard-wired logic.

12. The display device of claim 1, wherein the touch determination unit comprises an advanced RISC machine (ARM) processor.

13. The display device of claim 12, wherein the touch determination unit further comprises:

a data classification unit for classifying the detection data into row and column detection data; and

a memory for storing the classified row and column detection data.

14. A driving method of a display device comprising a plurality of detection units for detecting touch and a plurality of pixels, comprising:

reading an output signal from a detection unit for the row and column directions to generate detection data;

classifying the row and column detection data according to the direction and changing of the row or column coordinate of the touch position or sustaining a previous coordinate by comparing the detection data of each direction with a reference value of each direction; and

determining whether a touch has occurred according to a change of the touch position.

15. The driving method of claim 14, wherein the determining of the touch position comprises:

classifying the row and column detection data according to the direction;

selecting a representative value of the detection data of each direction;

comparing a representative value of each direction with the reference value; and

changing or sustaining a coordinate of a touch position according to a compared result.

16. The driving method of claim 15, wherein the representative value is the largest value of a plurality of detection data.

17. The driving method of claim 16, wherein the determining the touch position comprises:

determining a coordinate of the representative value as a touch position if the representative value is greater than the reference value; and

determining a previous touch position as a current touch position if the representative value is smaller than or equal to the reference value.

18. The driving method of claim 17, wherein the determining of whether a touch has occurred comprises

determining that the touch has occurred if both of the row and column coordinates of the touch position are changed, and determining that the touch has not occurred if both of the row and column coordinates of the touch position are not changed.

19. The driving method of claim 18, wherein the determining of whether the touch has occurred comprises sustaining a previous touch state if one of the row and column coordinates of the touch position is changed.

20. The driving method of claim 19, wherein the element output signal is generated according to a change of capacitance caused by the touch.

21. The driving method of claim 20, wherein the detection data are generated according to the difference between a previous element output signal and a current element output signal.