EMBEDDED TOUCH SCREEN

• US 20130215057A1
• Filed: 02/19/2013
• Published: 08/22/2013
• Est. Priority Date: 02/20/2012
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Corporation of America (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Liquid Crystal Display Company Limited (Panasonic Holdings Corporation)
• Inventors: KAWACHI, Genshiro, KITA, Kazuo, ONO, Kikuo
• Granted Patent: US 9,483,987 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

Provided is an embedded touch screen, including: a first substrate; a second substrate including: scanning signal lines extending in a first direction; video signal lines extending in a second direction; a plurality of pixels each including a pixel electrode connected to corresponding one of the video signal lines via a switching element connected to corresponding one of the scanning signal lines; and a common electrode; a liquid crystal layer; an application circuit for applying an alternating signal to a plurality of excitation electrodes; a detection circuit for detecting a signal excited on a plurality of detection electrodes each arranged adjacent to each of the plurality of excitation electrodes; and a scanning circuit for scanning at least one of each of the plurality of excitation electrodes and each of the plurality of detection electrodes at least in the second direction.

Claims

1. An embedded touch screen, comprising:

a first substrate;

a second substrate comprising, on a front surface thereof;

a plurality of scanning signal lines extending in a first direction;

a plurality of video signal lines extending in a second direction;

a plurality of pixels sectioned by the plurality of scanning signal lines and the plurality of video signal lines in matrix being arranged in an image region and each comprising a pixel electrode connected to corresponding one of the plurality of video signal lines via the switching element connected to corresponding one of the plurality of scanning signal lines; and

a common electrode;

a liquid crystal layer sandwiched between the first substrate and the second substrate;

an application circuit for applying an alternating signal to a plurality of excitation electrodes each arranged along one of the first direction and the second direction;

a detection circuit for detecting a signal excited on a plurality of detection electrodes each arranged adjacent to each of the plurality of excitation electrodes; and

a scanning circuit for scanning, during application by the application circuit and detection by the detection circuit, at least one of the plurality of excitation electrodes and the plurality of detection electrodes at least in the second direction.

2. The embedded touch screen according to claim 1, wherein the plurality of excitation electrodes and the plurality of detection electrodes each comprise at least one of the pixel electrode, the common electrode, each of the plurality of video signal lines, and a video signal shielding electrode provided in parallel to the each of the plurality of video signal lines in an overlapping manner.

3. The embedded touch screen according to claim 1, wherein, during the application by the application circuit and the detection by the detection circuit, the detection circuit simultaneously detects the signals excited on the plurality of detection electrodes in the second direction.

4. The embedded touch screen according to claim 1, wherein, during the application by the application circuit and the detection by the detection circuit, the detection circuit detects the signals excited on the plurality of detection electrodes through the scanning in the second direction.

5. The embedded touch screen according to claim 1,

wherein the plurality of excitation electrodes and the plurality of detection electrodes each cross a part of the plurality of pixels in a width direction orthogonal to an arrangement direction thereof.

6. The embedded touch screen according to claim 5, wherein a pitch between corresponding one of the plurality of excitation electrodes and corresponding one of the plurality of detection electrodes, which are adjacent to each other, is larger than a distance between a front surface of the first substrate and the front surface of the second substrate.

7. The embedded touch screen according to claim 1, wherein the application circuit applies an alternating signal, which has a phase reversed by 180°

with respect to an alternating signal applied to one of excitation electrodes adjacent to corresponding one of the plurality of detection electrodes, to another of the excitation electrodes adjacent to the corresponding one of the plurality of detection electrodes.

8. The embedded touch screen according to claim 1, wherein the detection circuit obtains a difference between the signal excited by the corresponding one of the plurality of detection electrodes and an alternating signal in the same phase as the alternating signal applied by the application circuit.

19. The embedded touch screen according to claim 1, further comprising a video display circuit for writing a video signal into the pixel electrode,

wherein the video signal is updated in a period corresponding to a frame, the frame including:

a writing period in which the video display circuit writes the video signal; and

a detection period in which the application by the application circuit and the detection by the detection circuit are performed, and

wherein, during the detection period, one of causing the pixel electrode to hold a signal for black display and turning OFF a backlight unit is performed.

20. The embedded touch screen according to claim 1, further comprising a video display circuit for writing a video signal into the pixel electrode,

wherein the video signal is updated in a period corresponding to a frame, the frame including:

a writing period in which the video display circuit writes the video signal; and

a detection period in which the application by the application circuit and the detection by the detection circuit are performed, and

wherein, during the detection period, the pixel electrode holds the video signal, and one of the alternating signal applied by the application circuit and a signal excited by the alternating signal is superimposed to the pixel electrode.

9. An embedded touch screen, comprising:

a first substrate;

a second substrate comprising, on a front surface thereof;

a plurality of scanning signal lines extending in a first direction;

a plurality of video signal lines extending in a second direction;

a plurality of pixels sectioned by the plurality of scanning signal lines and the plurality of video signal lines in matrix being arranged in an image region and each comprising a pixel electrode connected to corresponding one of the plurality of video signal lines via a switching element connected to corresponding one of the plurality of scanning signal lines; and

a common electrode;

a liquid crystal layer sandwiched between the first substrate and the second substrate;

an application circuit for applying an alternating signal to corresponding one of a plurality of excitation electrodes; and

a detection circuit for detecting a signal excited on a plurality of first detection electrodes each arranged along the first direction, and for detecting a signal excited on a plurality of second detection electrodes each arranged along the second direction.

10. The embedded touch screen according to claim 9,

wherein adjacent two of the plurality of excitation electrodes has a clearance therebetween, the clearance extending in at least one of the first direction and the second direction, and

wherein at least one of each of the plurality of first detection electrodes and each of the plurality of second detection electrodes is arranged at a position overlapping with the clearance in plan view.

11. The embedded touch screen according to claim 9,

wherein the plurality of excitation electrodes comprise:

a plurality of first excitation electrodes each arranged along the first direction; and

a plurality of second excitation electrodes each arranged along the second direction, and

wherein the plurality of first detection electrodes are each arranged adjacent to each of the plurality of first excitation electrodes, and the plurality of second detection electrodes are each arranged adjacent to each of the plurality of second excitation electrodes.

12. The embedded touch screen according to claim 9, wherein the plurality of excitation electrodes, the plurality of first detection electrodes, and the plurality of second detection electrodes each comprise at least one of the pixel electrode, the common electrode, each of the plurality of video signal lines, and a video signal shielding electrode provided in parallel to the each of the plurality of video signal lines in an overlapping manner.

13. The embedded touch screen according to claim 9, wherein, during application by the application circuit and detection by the detection circuit, the detection circuit simultaneously detects the signals excited on the plurality of first detection electrodes in the second direction, and simultaneously detects the signals excited on the plurality of second detection electrodes in the first direction.

14. The embedded touch screen according to claim 9, wherein, during application by the application circuit and detection by the detection circuit, the detection circuit detects the signals excited on the plurality of first detection electrodes through scanning in the second direction, and detects the signals excited on the plurality of second detection electrodes through scanning in the first direction.

15. The embedded touch screen according to claim 9,

wherein the plurality of excitation electrodes, the plurality of first detection electrodes, and the plurality of second detection electrodes each cross a part of the plurality of pixels in a width direction orthogonal to an arrangement direction thereof.

16. The embedded touch screen according to claim 15, wherein a pitch between corresponding one of the plurality of excitation electrodes and corresponding one of the plurality of first detection electrodes, which are adjacent to each other, and a pitch between corresponding one of the plurality of excitation electrodes and corresponding one of the plurality of second detection electrodes, which are adjacent to each other, are larger than a distance between a front surface of the first substrate and the front surface of the second substrate.

17. The embedded touch screen according to claim 9,

wherein the application circuit applies an alternating signal, which has a phase reversed by 180°

with respect to an alternating signal applied to one of excitation electrodes adjacent to corresponding one of the plurality of first detection electrodes, to another of the excitation electrodes adjacent to the corresponding one of the plurality of first detection electrodes, and

wherein the application circuit applies an alternating signal, which has a phase reversed by 180°

with respect to an alternating signal applied to one of excitation electrodes adjacent to corresponding one of the plurality of second detection electrodes, to another of the excitation electrodes adjacent to the corresponding one of the plurality of second detection electrodes.

18. The embedded touch screen according to claim 9, wherein the detection circuit obtains a difference between the signals excited on the plurality of first detection electrodes and an alternating signal having the same phase as the alternating signal applied by the application circuit, and obtains a difference between the signals excited on the plurality of second detection electrodes and the alternating signal having the same phase as the alternating signal applied by the application circuit.