Touch sensitive display device and driving apparatus thereof, and method of detecting a touch

• US 7,920,128 B2
• Filed: 09/20/2006
• Issued: 04/05/2011
• Est. Priority Date: 09/21/2005
• Status: Expired due to Fees

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Electronics Limited (Samsung Electronics Co. Ltd.)
• Inventors: Cho, Man-Seung, Lee, Joo-Hyung, Park, Jong-Woung, Uh, Kee-Han, Cha, Young-Ok
• Primary Examiner(s): Dharia; Prabodh M
• Application Number:
  US11/524,827
• Publication Number:
  US 20070063990A1
• Time in Patent Office: 1,658 Days
• Field of Search: 345/82, 345/104, 345173-184, 345/204, 345/211, 345/902, 345/50, 345/87, 345/92, 345/156, 345/594, 710/316, 315/169.2, 315/149, 386/54, 386/55, 178/18.01, 178/18.02, 178/19.03, 341/31, 349/12, 349/24
• US Class Current: 345/173
• 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 3/044 by capacitive means
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: G06F 3/0447 Position sensing using the local deformation of sensor cells
• CPC Class Codes: G06F 3/047 using sets of wires, e.g. crossed wires

Abstract

According to an embodiment of the present invention, a display device may include a display panel, a plurality of pixels disposed on the display panel, a plurality of first sensing units disposed on the display panel and generating first sensing signals in response to a touch exerted on the display panel, and a sensing signal processor configured to process the first sensing signals and generate second sensing signals for a plurality of frames, the sensing signal processor determining whether a touch occurs based on the second sensing signals for the plurality of frames.

Claims

1. A display device, comprising:

a display panel;

a plurality of pixels disposed on the display panel;

a plurality of first sensing units disposed on the display panel and generating first sensing signals in response to a touch exerted on the display panel; and

a sensing signal processor configured to process the first sensing signals and generate second sensing signals for a plurality of frames, the sensing signal processor determining whether a touch occurs based on the second sensing signals for the plurality of frames, and the sensing signal processor determines whether a touch begins based on differences in the second sensing signals between a first frame and at least one second frame previous to the first frame, and determines whether a touch ends in the first frame based on differences in the second sensing signals between the first frame and a third frame previous to the first frame and between the third frame and one or more fourth frames that occur between the third frame and the first frame.

2. The display device of claim 1, wherein the sensing signal processor determines whether a touch occurs based on differences in the second sensing signals between the plurality of frames.

3. The display device of claim 2, wherein the sensing signal processor determines whether a touch occurs in the first frame based on differences in the second sensing signals between the first frame and at least one second frame previous to the first frame.

4. The display device of claim 2, wherein the sensing signal processor determines whether a touch occurs in the first frame based on differences in the second sensing signals between the first frame and the second frame previous to the first frame and between the second frame and the third frames that occur between the second frame and the first frame.

5. The display device of claim 1, wherein the sensing signal processor calculates a first difference data for the first frame that is defined as a maximum of subtractions of the second sensing signals for the second frame previous to the first frame from the second sensing signal for the first frame, and determines that a touch begins when the first difference data is equal to or greater than a first positive value.

6. The display device of claim 5, wherein the sensing signal processor calculates a second difference data for the first frame that is defined as a maximum of subtractions of the second sensing signals for the first frame and for third frame previous to the first frame from the second sensing signal for the fourth frames that occur between the third frame and the first frame, and determines that a touch ends when the second difference data is equal to or greater than a second positive value.

7. The display device of claim 1, wherein the sensing signal processor calculates a first difference data for the first frame that is defined as a minimum of subtractions of the second sensing signals for the second frame previous to the first frame from the second sensing signal for the first frame, and determines that a touch begins when the first difference data is equal to or smaller than a first negative value.

8. The display device of claim 7, wherein the sensing signal processor calculates a second difference data for the first frame that is defined as a minimum of subtractions of the second sensing signals for the first frame and for a third frame previous to the first frame from the second sensing signal for the fourth frames that occur between the third frame and the first frame, and determines that the touch ends when the second difference data is equal to or smaller than a second negative value.

9. The display device of claim 1, further comprising a frame memory configured for storing and providing the second sensing signals.

10. The display device of claim 1, wherein the sensing signal processor is configured to amplify the first sensing signals to provide amplified first sensing signals, the sensing signal process being configured to digitize the amplified first sensing signals.

11. The display device of claim 10, wherein the sensing signal processor averages the digitized first sensing signals over the plurality of frames to generate the second sensing signals.

12. The display device of claim 1, wherein the plurality first sensing units comprise a plurality of rows of second sensing units and a plurality of columns of third sensing units, wherein the second sensing units in each row are connected to each other, and the third sensing units in each column are connected to each other.

13. The display device of claim 12, further comprising:

a plurality of first sensor data lines connected to the second sensing units, the plurality of first sensor data lines extending in a row direction and being configured to transmit the first sensing signals from the second sensing units; and

a plurality of second sensor data lines connected to the third sensing units, the plurality of second sensor data lines extending in a column direction and being configured to transmit the first sensing signals from the third sensing units.

14. The display device of claim 13, wherein the sensing signal processor determines an occurrence of a touch based on each of the first sensing signals and determines a position of a touch depending on the determination of an occurrence of a touch.

15. The display device of claim 1, wherein the plurality of first sensing units are configured to sense pressure exerted on the display panel.

16. The display device of claim 15, further comprising a plurality of second sensing units configured to sense ambient light and to generate third sensing signals, wherein the sensing signal processor determines a position of a touch based on the third sensing signals.

17. The display device of claim 16, wherein the sensing signal processor converts the third sensing signals to fourth sensing signals, the sensing signal processor being configured to apply an edge detection algorithm to the fourth sensing signals to determine where the touch occurs.

18. An apparatus for driving a display panel including a plurality of sensing units configured to generate a plurality of first sensing signals in response to a touch exerted on the display panel, the apparatus comprising:

a sensing signal processor configured to generate a plurality of second sensing signals for a plurality of frames based on the first sensing signals from the display panel and determining whether a touch occurs based on the second sensing signals for the plurality of frames; and

a frame memory configured to store at least one of the first and second sensing signals wherein the sensing signal processor is configured to determine that a touch begins in a current frame when a first difference data for the current frame is equal to or greater than a first positive value, and the first difference data for the current frame is defined as a maximum of subtractions of the second sensing signals for a first predetermined number of previous frames from the second sensing signal for the current frame, and

wherein the sensing signal processor is configured to determine that a touch ends in the current frame when a second difference data for the current frame is equal to or greater than a second positive value, and the second difference data for the current frame is defined as a maximum of subtractions of the second sensing signals for the current frame and for a second predetermined number of previous frames from the second sensing signal for another frame before the second predetermined number of previous frames.

19. The apparatus of claim 18, wherein the sensing signal processor is configured to amplify the first sensing signals to provide amplified first sensing signals, the sensing signal processor being configured to digitize the amplified first sensing signals.

20. The driving apparatus of claim 19, wherein the sensing signal processor averages the digitized first sensing signals over the plurality of frames to generate the second sensing signals.

21. A method of detecting a touch exerted on a display panel, the method comprising:

generating a plurality of pointwise sensor output signals in response to a touch exerted on the display panel;

collecting the sensor output signals in rows and columns to generate a sensor data signal for each row and for each column corresponding to each frame of a plurality of frames; and

determining whether a touch occurs based on the sensor data signals for the plurality of frames; and

wherein the operation of determining whether a touch occurs comprises;

calculating a first difference data for a current frame equal to a maximum of subtractions of the sensor data signals for a first predetermined number of frames previous to the current frame from the sensor data signal for the current frame; and

comparing the first difference data with a first predetermined value, wherein it is determined that a touch begins when the first difference data is equal to or greater than the first predetermined value; and

wherein the operation of determining whether a touch occurs further comprises;

calculating a second difference data for a current frame equal to a maximum of subtractions of the sensor data signals for the current frame and for a second predetermined number of frames previous to the current frame from the second sensing signal for another frame previous to the second predetermined number of previous frames; and

comparing the second difference data with a second predetermined value, wherein it is determined that a touch ends when the second difference data is equal to or greater than the second predetermined value.

22. The method of claim 21, further comprising:

amplifying the sensor data signals;

digitizing the amplified sensor data signals; and

averaging the digitized sensor data signals over a predetermined number of frames.