SYSTEM AND METHOD TO DRIVE TOUCH PANEL TO MEASURE HOVER

• US 20140375598A1
• Filed: 12/17/2013
• Published: 12/25/2014
• Est. Priority Date: 06/19/2013
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Maxim Integrated Products, Inc. (Analog Devices, Inc.)
• Inventors: Shen, Guozhong, Erdogan, Ozan E., Christman, Daniel S.
• Granted Patent: US 9,477,356 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• 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 3/04166 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 3/0443 using a single layer of sensing electrodes
• 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

Techniques in accordance with the present disclosure allow the detection of hover events and/or touch events performed over the touch panel without requiring that the touch panel be equipped with additional hardware and/or materials. In one or more implementations, the apparatus includes a touch panel controller configured to operatively couple to a touch panel sensor. The touch panel sensor includes at least one drive electrode and at least one sense electrode. The touch panel controller includes output circuitry operatively coupled to the at least one drive electrode. The output circuitry is configured to generate drive signals to drive the drive electrode (i.e., drive the touch panel sensor). The touch panel controller also includes input circuitry operatively coupled to the at least one sense electrode. The input circuitry is configured to measure mutual-capacitance between the at least drive electrode and the at least one sense electrode to detect a hover event. The present disclosure is directed to driving a subset of rows (or columns) and senses the subset of the remaining rows (or columns). Thus, the same sensor can measure multi-touch event and hover without changes to sensor pattern.

Claims

1. An apparatus comprising:

a touch panel controller configured to operatively couple to a touch panel sensor, the touch panel sensor including at least one drive electrode and at least one sense electrode, the at least one sense electrode in parallel with the at least one drive electrode, the touch panel controller comprising;

output circuitry operatively coupled to the at least one drive electrode, the output circuitry configured to generate drive signals to drive the at least one drive electrode; and

input circuitry operatively coupled to the at least one sense electrode, the input circuitry configured to measure mutual-capacitance between the at least one drive electrode and the at least one sense electrode to detect a hover event.

2. The apparatus as recited in claim 1, further comprising an intermediary electrode disposed between the at least one drive electrode and the at least one sense electrode.

3. The apparatus as recited in claim 1, wherein the at least one drive electrode is adjacent to the at least one sense electrode.

4. The apparatus as recited in claim 1, wherein the output circuitry comprises a digital-to-analog converter coupled to a buffer, the buffer coupled to at least one drive electrode of the plurality of drive electrodes.

5. The apparatus as recited in claim 1, wherein the input circuitry comprises a charge amplifier, the charge amplifier further comprising an operational amplifier having an inverting input terminal, a non-inverting input terminal, and an output terminal, the inverting input terminal coupled to at least one sense electrode;

and an integrating capacitor electrically coupled between the inverting input terminal and the output terminal.

6. The apparatus as recited in claim 1, wherein the controller is configured to cause the output circuitry to drive a first subset of row electrodes during a first time interval;

sense a change in mutual-capacitance between the first subset of row electrodes and a second subset of row electrodes during the first time interval to detect a hover event associated with the row electrodes;

cause the output circuitry to drive a first subset of column electrodes during a second time interval;

sense a change in mutual-capacitance between the first subset of column electrodes and a second subset of column electrodes during the second time interval to detect a hover event associated with the column electrodes; and

approximate a position of a hover event based upon the hover event associated with the row electrodes and the hover event associated with the column electrodes.

7. The apparatus as recited in claim 6, wherein approximate a position further comprises approximate a position of the hover event based upon the intersection of the hover event associated with the row electrodes and the hover event associated with the column electrodes.

8. An apparatus comprising:

a touch panel controller configured to operatively couple to a touch panel sensor, the touch panel sensor including a plurality of electrodes, the plurality of electrodes including a first subset of electrodes and a second subset of electrodes, the second subset of electrodes non-intersecting with the first subset of electrodes, the touch panel controller comprising;

output circuitry operatively coupled to the plurality of electrodes, the output circuitry configured to generate drive signals to drive the first subset of electrodes; and

input circuitry operatively coupled to the second subset of electrodes, the input circuitry configured to measure mutual-capacitance between the first subset of electrodes and the second subset of electrodes to detect a hover event.

9. The apparatus as recited in claim 8, wherein the plurality of electrodes comprise rows of electrodes.

10. The apparatus as recited in claim 8, wherein the plurality of electrodes comprise columns of electrodes.

11. The apparatus as recited in claim 8, wherein the output circuitry comprises a digital-to-analog converter coupled to a buffer, the buffer coupled to at least one drive electrode of the plurality of drive electrodes.

12. The apparatus as recited in claim 8, wherein the input circuitry comprises a charge amplifier, the charge amplifier further comprising an operational amplifier having an inverting input terminal, a non-inverting input terminal, and an output terminal, the inverting input terminal coupled to at least one sense electrode;

and an integrating capacitor electrically coupled between the inverting input terminal and the output terminal.

13. The apparatus as recited in claim 8, wherein the controller is configured to cause the output circuitry to drive a first subset of row electrodes during a first time interval;

sense a change in mutual-capacitance between the first subset of row electrodes and a second subset of row electrodes during the first time interval to detect a hover event associated with the row electrodes;

cause the output circuitry to drive a first subset of column electrodes during a second time interval;

sense a change in mutual-capacitance between the first subset of column electrodes and a second subset of column electrodes during the second time interval to detect a hover event associated with the column electrodes; and

approximate a position of a hover event based upon the hover event associated with the row electrodes and the hover event associated with the column electrodes.

14. The apparatus as recited in claim 13, wherein approximate a position further comprises approximate a position of the hover event based upon the intersection of the hover event associated with the row electrodes and the hover event associated with the column electrodes.

15. A method comprising:

driving a first subset of row electrodes during a first time interval by way of output circuitry;

sensing a change in mutual-capacitance between the first subset of row electrodes and a second subset of row electrodes during the first time interval to detect a hover event associated with the row electrodes;

driving a first subset of column electrodes during a second time interval by way of output circuitry;

sensing a change in mutual-capacitance between the first subset of column electrodes and a second subset of column electrodes during the second time interval to detect a hover event associated with the column electrodes; and

approximating a position of a hover event based upon the hover event associated with the row electrodes and the hover event associated with the column electrodes.

16. The method as recited in claim 15, wherein the approximating the position comprises approximating a position of the hover event based upon the intersection of the hover event associated with the row electrodes and the hover event associated with the column electrodes.

17. The method as recited in claim 15, wherein an intermediary electrode is disposed between at least one row electrode of the first subset of row electrodes and at least one row electrode of the second subset of row electrodes.

18. The method as recited in claim 15, wherein an intermediary electrode is disposed between at least one column electrode of the first subset of column electrodes and at least one row electrode of the second subset of column electrodes.

19. The method as recited in claim 15, wherein the output circuitry comprises a digital-to-analog converter coupled to a buffer, the buffer coupled to at least one drive electrode of the plurality of drive electrodes.

20. The method as recited in claim 15, wherein wherein the input circuitry comprises a charge amplifier, the charge amplifier further comprising an operational amplifier having an inverting input terminal, a non-inverting input terminal, and an output terminal, the inverting input terminal coupled to at least one sense electrode;

and an integrating capacitor electrically coupled between the inverting input terminal and the output terminal.