Touch sensor and display device

• US 10,139,963 B2
• Filed: 03/26/2014
• Issued: 11/27/2018
• Est. Priority Date: 06/30/2009
• Status: Active Grant

• Current Assignee: Japan Display Incorporated
• Original Assignee: Japan Display Incorporated
• Inventors: Ishizaki, Koji, Noguchi, Kouji, Harada, Tsutomu, Takeuchi, Takeya, Kida, Yoshitoshi, Nakanishi, Takayuki
• Primary Examiner(s): Haley, Joseph
• Application Number:
  US14/226,460
• Publication Number:
  US 20140204060A1
• Time in Patent Office: 1,707 Days
• Field of Search: 345173-178, 178 1801- 1809, 178 1811
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G06F 2203/04101 2.5D-digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface and also measures the distance of the input means within a short range in the Z direction, possibly with a separate measurement setup
• CPC Class Codes: G06F 2203/04108 Touchless 2D- digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface without distance measurement in the Z direction
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• 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: G09G 3/3611 Control of matrices with row and column drivers

Abstract

A touch sensor that may detect an object away from the sensor is provided. The touch sensor includes one or more drive electrodes; one or more detection electrodes forming capacitance in cooperation with the respective drive electrodes; a detection circuit applying drive signals to the respective drive electrodes to detect the object based on detection signals obtained from the respective detection electrodes in response to the respective drive signals; and a controller controlling to change a range of electric flux lines generated between the drive electrodes and the detection electrodes.

Claims

1. A touch sensor comprising:

a plurality of electrodes including a plurality of common electrodes;

a detection circuit applying a drive signal to at least one of the electrodes to output a detection result based on a detection signal obtained from the electrodes in response to the drive signal; and

a controller operating to change a range of electric lines of force generated by the electrodes, wherein

the controller causes a change in a maximum range of the electric lines of force in accordance with the detection result,

the electrodes have a plurality of first electrodes extending along a first direction and a plurality of second electrodes extending along a second direction perpendicular to the first direction, and

the controller causes a pixel voltage of a pixel to be higher than an off voltage of a gate of a corresponding pixel TFT, after applying a drive signal to at least one of the common electrodes.

2. The touch sensor according to claim 1, further comprising a first timing controller driving a plurality of drive electrodes of the electrodes in such a manner that one or more drive electrodes are selected to be driven at a time, while such a selection of the drive electrodes is shifted in sequence, thereby allowing all the drive electrodes to be scanned for driving,

wherein the controller changes the number of the drive electrodes to be selected in accordance with the detection result.

3. The touch sensor according to claim 1, having a first detection mode in which the number of a plurality of drive electrodes of the electrodes to be selected is relatively large and a second detection mode in which the number of the drive electrodes to be selected is relatively small,

wherein the detection circuit detects presence of an object in the first detection mode, and detects a position of the object in the second detection mode.

4. The touch sensor according to claim 3, further having another detection mode or two or more other detection modes, the number of the drive electrodes selected in each of the another detection mode or the other detection modes lying between the number of the drive electrodes selected in the first detection mode and the number of the drive electrodes selected in the second detection mode, wherein

the detection circuit detects presence of the object in each detection mode, and then outputs, for each detection mode, the detection result to the controller, and

the controller increases or decreases the number of the drive electrodes to be selected based on the detection result.

5. The touch sensor according to claim 4, wherein

the controller decreases the number of the drive electrodes to be selected when presence of the object is detected by the detection circuit, and

the controller increases the number of the drive electrodes to be selected when presence of the object is not detected by the detection circuit.

6. The touch sensor according to claim 1, further comprising a second timing controller selectively allowing one or more of the electrodes to be valid,

wherein the controller changes the number of the electrodes to be selected in accordance with the detection result.

7. The touch sensor according to claim 6, having a first detection mode in which the number of the electrodes to be selected is relatively small and a second detection mode in which the number of the electrodes to be selected is relatively large,

wherein the detection circuit detects presence of an object in the first detection mode, and detects a position of the object in the second detection mode.

8. The touch sensor according to claim 7, further having another detection mode or two or more other detection modes, the number of the electrodes selected in each of the another detection mode or the other detection modes lying between the number of the electrodes selected in the first detection mode and the number of the electrodes selected in the second detection mode, wherein

the detection circuit detects presence of the object in each detection mode, and then outputs, for each detection mode, the detection result to the controller, and

the controller increases or decreases the number of the electrodes to be selected based on the detection result.

9. The touch sensor according to claim 1, further comprising a third timing controller driving a plurality of drive electrodes of the electrodes through applying the drive signal to the drive electrodes in sequence,

wherein the controller changes amplitude of the drive signal in accordance with the detection result.

10. The touch sensor according to claim 9, having a first detection mode in which the amplitude of the drive signal is relatively large and a second detection mode in which the amplitude of the drive signal is relatively small, wherein the detection circuit detects presence of an object in the first detection mode, and detects a position of the object in the second detection mode.

11. The touch sensor according to claim 10, further having another detection mode or two or more other detection modes, amplitude of the drive signal used in each of the another detection mode or the other detection modes lying between the amplitude of the drive signal used in the first detection mode and the amplitude of the drive signal used in the second detection mode, wherein

the detection circuit detects presence of the object in each detection mode, and then outputs, for each detection mode, the detection result to the controller, and

the controller performs control of increasing or decreasing the amplitude of the drive signal based on the detection result.

12. A display unit comprising the touch sensor according to claim 1.

13. The touch sensor according to claim 12, wherein the controller selects from plural distance detection modes, each having a different range of reach for the electric lines of force generated between the electrodes.

14. A display unit comprising:

a plurality of display pixel electrodes;

a plurality of electrodes including a plurality of common electrodes provided to face the display pixel electrodes, the common electrodes separately providing a sensor-purpose drive signal;

a display layer;

a display control circuit controlling image display performance of the display layer through applying an image-signal-based-voltage between the display pixel electrodes and the common electrodes;

a detection circuit which outputs a detection result based on the sensor-purpose drive signal;

a controller operating to change a range of electric lines of force generated by the electrodes;

a timing controller applying a display-purpose common drive signal and the sensor-purpose drive signal to the common electrodes at respective timings which are different from each other; and

TFT elements in correspondence to the display pixel electrodes, respectively, wherein

the controller causes a change in a maximum range of the electric lines of force in accordance with the detection result,

the electrodes have a plurality of first electrodes extending along a first direction and a plurality of second electrodes extending along a second direction perpendicular to the first direction, and

gate potential in an off state of each of the TFT elements satisfies following expression (1),

VgateL≤

VsigL−

Δ

Vcom+Vth 

 

(1)

where VgateL is off gate potential of each TFT element, VsigL is low potential of a video signal, Δ

Vcom is a difference between a minimum value and a maximum value of a sensor-purpose drive signal, and Vth is a threshold voltage of each TFT element.

15. The display unit according to claim 14, wherein the timing controller applies the sensor-purpose drive signal after a lapse of a certain period of time, from application of the display-purpose common-drive signal.

16. The display unit according to claim 14, wherein the timing controller applies the sensor-purpose drive signal only in a period corresponding to detection timing.