Touch sensor, display device, and electronic apparatus

• US 8,860,685 B2
• Filed: 05/13/2010
• Issued: 10/14/2014
• Est. Priority Date: 05/26/2009
• Status: Active Grant

• Current Assignee: Japan Display Incorporated
• Original Assignee: Japan Display West Incorporated (Japan Display Incorporated)
• Inventors: Takeuchi, Takeya, Noguchi, Koji, Ishizaki, Koji, Nakanishi, Takayuki, Teranishi, Yasuyuki
• Primary Examiner(s): Awad, Amr
• Assistant Examiner(s): Midkiff, Aaron
• Application Number:
  US12/662,976
• Publication Number:
  US 20100302202A1
• Time in Patent Office: 1,615 Days
• Field of Search: 178 1801- 2004, 345/104, 345173-178, 349/12
• US Class Current: 345/174
• CPC Class Codes: G06F 1/1643 the display being associated to a digitizer, e.g. laptops that can be used as penpads details related to the relative motion of the display enclosure with respect to the body enclosure, e.g. to move between laptop and tablet PC configuration G06F1/1615
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• 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: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes

Abstract

A touch sensor includes a touch drive electrode, a touch detection electrode provided opposed to or side by side with the touch drive electrode and forming an electrostatic capacitance between the touch detection electrode and the touch drive electrode, and a touch detection circuit detecting a contact or proximity position of an object on the basis of a detection signal obtained from the touch detection electrode by applying a touch sensor drive signal to the touch drive electrode. The touch drive electrode is split into plural stripe-like electrode patterns. Applying the touch sensor drive signal to part of the electrode patterns forms a drive line at that time. The touch detection circuit performs a detection on the basis of a first detection signal obtained from a first drive line formed in a first period, and a second detection signal obtained from a second drive line formed in a second period.

Claims

1. A touch sensor comprising:

a touch drive electrode;

a touch detection electrode provided in opposition to or side by side with the touch drive electrode and forming an electrostatic capacitance between the touch detection electrode and the touch drive electrode; and

a touch detection circuit that performs a detection of a contact or proximity position of an object, on the basis of a detection signal obtained from the touch detection electrode by applying a touch sensor drive signal to the touch drive electrode,

wherein the touch drive electrode is split into a plurality of electrode patterns in a stripe shape, and application of the touch sensor drive signal to part of the plurality of electrode patterns causes a drive line to be formed at that time,

the touch detection circuit performs the detection on the basis of a first detection signal obtained from a first drive line formed in a first period, and a second detection signal obtained from a second drive line formed in a second period different from the first period and having a smaller line width than the first drive line, and

the touch detection circuit performs the detection on the basis of a differential signal between the first detection signal and the second detection signal.

2. The touch sensor according to claim 1, wherein the first period and the second period are set alternately at a time ratio of 1 to 1.

3. The touch sensor according to claim 1, wherein:

the first period and the second period are set alternately at a time ratio of n (n;

an integer not smaller than

     2) to 1;

the first drive line includes a position detection drive line; and

within the first period, a sequential drive is performed with respect to the position detection drive line.

4. The touch sensor according to claim 3, wherein the first drive line includes the position detection drive line and a noise detection drive line having a line width equal to the line width of the second drive line.

5. The touch sensor according to claim 1, wherein:

detection modes can be switched between a first detection mode and a second detection mode;

the first detection mode is a mode in which the first period and the second period are set alternately at a time ratio of 1 to 1; and

the second detection mode is a mode in which the first period and the second period are set alternately at a time ratio of n (n;

an integer not smaller than

     2) to 1, the first drive line includes a position detection drive line, and a sequential drive is performed with respect to the position detection drive line within the first period.

6. The touch sensor according to claim 5, wherein the first drive line includes the position detection drive line and a noise detection drive line having a line width equal to the line width of the second drive line.

7. The touch sensor according to claim 1, wherein:

the first period and the second period are set alternately in a time division manner;

the first drive line includes a position detection drive line; and

the position detection drive line is set at arbitrary positions within the touch drive electrode which differ from each other between the first period and the second period.

8. The touch sensor according to claim 7, wherein the first drive line includes the position detection drive line and a noise detection drive line having a line width equal to the line width of the second drive line.

9. The touch sensor according to claim 1, wherein the first drive line in the first period, and the second drive line in the second period are located on substantially the same line within the touch drive electrode.

10. A display device comprising:

a plurality of display pixel electrodes;

a common electrode provided in opposition to the display pixel electrodes;

a display function layer having an image display function;

a display control circuit that controls image display on the basis of an image signal so as to apply a display drive voltage between the display pixel electrodes and the common electrode to cause the display function layer to exert the image display function, on the basis of an image signal;

a touch detection electrode provided in opposition to or side by side with the common electrode and forming an electrostatic capacitance between the touch detection electrode and the common electrode; and

a touch detection circuit that performs a detection of a contact or proximity position of an object, on the basis of a detection signal obtained from the touch detection electrode, by using the display drive voltage applied to the common electrode by the display control circuit as a touch sensor drive signal,

wherein the common electrode is split into a plurality of electrode patterns in a stripe shape, and application of the touch sensor drive signal to part of the plurality of electrode patterns causes a drive line to be formed at that time,

the touch detection circuit performs the detection on the basis of a first detection signal obtained from a first drive line formed in a first period, and a second detection signal obtained from a second drive line formed in a second period different from the first period and having a smaller line width than the first drive line, and

the touch detection circuit performs the detection on the basis of a differential signal between the first detection signal and the second detection signal.

11. The display device according to claim 10, wherein:

the first drive line includes a position detection drive line and a noise detection drive line having a line width equal to the line width of the second drive line; and

the noise detection drive line and the second drive line are each made common with an image display drive line for performing image display by the display control circuit.

12. The display device according to claim 10, wherein the display control circuit performs a sequential drive with respect to the drive line formed as a batch of two or more electrode patterns of the plurality of electrode patterns.

13. The display device according to claim 10, further comprising:

a circuit board on which the display control circuit is formed; and

a counter substrate disposed in opposition to the circuit board,

wherein the display pixel electrodes are disposed on a side of the circuit board close to the counter substrate,

the common electrode is disposed on a side of the counter substrate close to the circuit board, and

the display function layer is inserted between the display pixel electrodes on the circuit board, and the common electrode on the counter substrate.

14. The display device according to claim 13, wherein the display function layer is a liquid crystal layer.

15. The display device according to claim 10, further comprising:

a circuit board on which the display control circuit is formed; and

a counter substrate disposed in opposition to the circuit board,

wherein the common electrode and the display pixel electrodes are laminated on the circuit board via an insulating layer, and

the display function layer is inserted between the display pixel electrodes on the circuit board, and the counter substrate.

16. The display device according to claim 15, wherein the display function layer is a liquid crystal layer, and performs liquid crystal display in a transverse electric field mode.

17. An electronic apparatus comprising a display device with a touch sensor, the display device including:

a plurality of display pixel electrodes;

a common electrode provided in opposition to the display pixel electrodes;

a display function layer having an image display function;

a display control circuit that controls image display on the basis of an image signal so as to apply a display drive voltage between the display pixel electrodes and the common electrode to cause the display function layer to exert the image display function, on the basis of an image signal;

a touch detection electrode provided in opposition to or side by side with the common electrode and forming an electrostatic capacitance between the touch detection electrode and the common electrode; and

a touch detection circuit that performs a detection of a contact or proximity position of an object, on the basis of a detection signal obtained from the touch detection electrode, by using the display drive voltage applied to the common electrode by the display control circuit as a touch sensor drive signal,

wherein the common electrode is split into a plurality of electrode patterns in a stripe shape, and application of the touch sensor drive signal to part of the plurality of electrode patterns causes a drive line to be formed at that time,

the touch detection circuit performs the detection on the basis of a first detection signal obtained from a first drive line formed in a first period, and a second detection signal obtained from a second drive line formed in a second period different from the first period and having a smaller line width than the first drive line, and

the touch detection circuit performs the detection on the basis of a differential signal between the first detection signal and the second detection signal.

18. The electronic apparatus according to claim 17, wherein:

the first drive line includes a position detection drive line and a noise detection drive line having a line width equal to the line width of the second drive line; and

the noise detection drive line and the second drive line are each made common with an image display drive line for performing image display by the display control circuit.

19. The electronic apparatus according to claim 17, wherein the display control circuit performs a sequential drive with respect to the drive line formed as a batch of two or more electrode patterns of the plurality of electrode patterns.

20. The electronic apparatus according to claim 17, wherein:

the first period and the second period are set alternately in a time division manner;

the first drive line includes a position detection drive line; and

the position detection drive line is set at arbitrary positions within the touch drive electrode which differ from each other between the first period and the second period.