Simultaneous self- and mutual capacitance sensing

• US 9,965,108 B2
• Filed: 05/16/2014
• Issued: 05/08/2018
• Est. Priority Date: 05/16/2014
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Li, Yingxuan, Yao, Weijun, Nho, Hyunwoo Henry, Yao, Wei Hsin
• Primary Examiner(s): Shen, Yuzhen
• Application Number:
  US14/279,692
• Publication Number:
  US 20150331535A1
• Time in Patent Office: 1,453 Days
• Field of Search: 345173
• 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 3/0443 using a single layer of sensing electrodes
• 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 controller. The touch controller can include first sense circuitry configured to be coupled to a first electrode on a touch sensor panel, the first sense circuitry configured to sense a first self-capacitance associated with the first electrode, and a first mutual capacitance associated with the first electrode. In some examples, the first sense circuitry can be configured to sense the first self-capacitance and the first mutual capacitance simultaneously. In some examples, the touch controller can further include a first mixer and a second mixer coupled to the first sense circuitry, the first mixer configured to demodulate a first output from the first sense circuitry to extract information about the first self-capacitance from the first output, the second mixer configured to demodulate the first output from the first sense circuitry to extract information about the first mutual capacitance from the first output.

Claims

1. A touch controller comprising:

first sense circuitry configured to be coupled to a first column electrode on a touch sensor panel and configured to drive the first electrode with a first signal;

second sense circuitry configured to be coupled to a first row electrode on the touch sensor and drive the second electrode with a second signal;

a first mixer and a second mixer coupled in parallel to an output of the first sense circuitry, the first mixer configured to demodulate the output from the first sense circuitry using the first signal to measure a first capacitance from the first output, the second mixer configured to simultaneously demodulate the output from the first sense circuitry using the second signal to measure a second capacitance from the first output, wherein the first signal is different from the second signal; and

a third mixer coupled to an output of the second sense circuitry, the third mixer configured to demodulate the output from the second sense circuitry using the second signal to measure a third capacitance from the second output simultaneously to the measurement of the first and second capacitance,

wherein the second capacitance comprises a mutual capacitance between the first electrode and the second electrode.

2. The touch controller of claim 1, wherein the first sense circuitry is configured to sense the first capacitance and the second capacitance simultaneously.

3. The touch controller of claim 1, wherein the first signal is orthogonal to the second signal.

4. The touch controller of claim 1, wherein

the second signal has a second frequency orthogonal to the first frequency, or the second signal has a different phase than the first signal.

5. The touch controller of claim 1, wherein the first electrode comprises a column electrode, and the second electrode comprises a row electrode orthogonal to the column electrode.

6. The touch controller of claim 1, further comprising:

third sense circuitry configured to be coupled to a third electrode on the touch sensor panel, the third sense circuitry configured to;

drive the third electrode with a third signal, the third signal having a third frequency orthogonal to the first frequency, or the third signal having a different phase than the first signal, and

sense a third self-capacitance associated with the third electrode based on the third signal,

wherein the first sense circuitry is further configured to sense a second mutual capacitance between the first electrode and the third electrode based on the third signal.

7. The touch controller of claim 1, wherein:

the first electrode is coupled to a first offset cancellation circuit, the first offset cancellation circuit configured to facilitate sensing of the first self-capacitance, and

the second electrode is coupled to a second offset cancellation circuit, the second offset cancellation circuit configured to facilitate sensing of the second self-capacitance.

8. The touch controller of claim 1, wherein:

the first electrode is coupled to a first offset cancellation circuit, the first offset cancellation circuit configured to facilitate sensing of the first self-capacitance.

9. The touch sensor panel incorporating the touch controller of claim 1.

10. A touch screen incorporating the touch sensor panel of claim 9.

11. A method for operating a touch controller, the method comprising:

driving, using first sense circuitry, a first column electrode on the touch sensor panel with a first signal;

sensing, using the first sense circuitry, a first output associated with the first electrode on the touch sensor panel;

driving, using second sense circuitry, a first column electrode on the touch sensor panel with a second signal;

sensing, using the second sense circuitry, a second output associated with the second electrode;

demodulating the output from the first sense circuitry at a first demodulator using the first signal to measure a first capacitance from the first output,

demodulating the output from the first sense circuitry at a second demodulator using the second signal to measure a second capacitance from the first output,

demodulating the output from the second sense circuitry using the second signal to measure a third capacitance from the second output;

wherein the first demodulator and the second demodulator are coupled in parallel to the first output from the first sense circuitry and the second capacitance comprises a mutual capacitance between the first electrode and the second electrode.

12. The method of claim 11, wherein the first signal is orthogonal to the second signal.

13. The method of claim 11,

wherein:

the first signal has a first phase and a first frequency; and

the second signal has a second frequency orthogonal to the first frequency, or the second signal has a different phase than the first signal.

14. The method of claim 11, wherein the first electrode comprises a column electrode, and the second electrode comprises a row electrode orthogonal to the column electrode.

15. The method of claim 11, further comprising:

driving, using third sense circuitry, a third electrode on the touch sensor panel with a third signal, the third signal having a third frequency orthogonal to the first frequency, or the third signal having a different phase than the first signal;

sensing, using the third sense circuitry, a third self-capacitance associated with the third electrode based on the third signal; and

sensing, using the first sense circuitry, a second mutual capacitance between the first electrode and the third electrode based on the third signal.

16. The method of claim 11, wherein:

the first electrode is coupled to a first offset cancellation circuit, the first offset cancellation circuit configured to facilitate sensing of the first capacitance, and

the second electrode is coupled to a second offset cancellation circuit, the second offset cancellation circuit configured to facilitate sensing of the third capacitance.

17. The method of claim 11, wherein:

the first electrode is coupled to a first offset cancellation circuit, the first offset cancellation circuit configured to facilitate sensing of the first self-capacitance.