Front-end signal compensation

• US 10,254,890 B2
• Filed: 04/07/2016
• Issued: 04/09/2019
• Est. Priority Date: 01/03/2007
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Hotelling, Steve Porter, Land, Brian Richards
• Primary Examiner(s): Nguyen, Jennifer T
• Application Number:
  US15/093,638
• Publication Number:
  US 20160224185A1
• Time in Patent Office: 1,097 Days
• Field of Search: 345173-178, 178 1806
• CPC Class Codes: G06F 2203/04104 Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger
• CPC Class Codes: G06F 2203/04107 Shielding in digitiser, i.e. guard or shielding arrangements, mostly for capacitive touchscreens, e.g. driven shields, driven grounds
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/04182 Filtering of noise external to the device and not generated by digitiser components
• CPC Class Codes: G06F 3/044 by capacitive means
• 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 surface device having improved sensitivity and dynamic range is disclosed. In one embodiment, the touch surface device includes a touch-sensitive panel having at least one sense node for providing an output signal indicative of a touch or no-touch condition on the panel; a compensation circuit, coupled to the at least one sense node, for generating a compensation signal that when summed with the output signal removes an undesired portion of the output signal so as to generated a compensated output signal; and an amplifier having an inverting input coupled to the output of the compensation circuit and a non-inverting input coupled to a known reference voltage.

Claims

1. A touch sensor panel for generating compensated touch signals, comprising:

a plurality of first electrodes; and

a plurality of second electrodes;

wherein the plurality of second electrodes include one or more shielding portions configured for substantially covering an entirety of one or more of the plurality of first electrodes, resulting in the one or more of the plurality of first electrodes becoming touch-insensitive first electrodes.

2. The touch sensor panel of claim 1:

wherein one or more of the plurality of first electrodes, different from the touch-insensitive first electrodes, are configured for receiving one or more first stimulation signals; and

wherein the one or more touch-insensitive first electrodes are configured for receiving one or more second stimulation signals while the one or more of the plurality of first electrodes, different from the touch-insensitive first electrodes, are receiving the one or more first stimulation signals, the one or more second stimulation signals phase-shifted 180 degrees from the one or more first stimulation signals.

3. The touch sensor panel of claim 1, wherein the plurality of second electrodes are configured for capacitively coupling with the plurality of first electrodes to generate the compensated touch signals.

4. The touch sensor panel of claim 3, wherein one or more of the plurality of second electrodes are configured for capacitively coupling with the one or more touch-insensitive first electrodes and at a same time configured for capacitively coupling with the one or more of the plurality of first electrodes, different from the touch-insensitive first electrodes, to generate the compensated touch signals.

5. The touch sensor panel of claim 4, wherein the one or more of the plurality of second electrodes are configured for producing a fixed capacitance with the one or more touch-insensitive first electrodes.

6. The touch sensor panel of claim 1, wherein the plurality of first electrodes are oriented orthogonal to the plurality of second electrodes, and the one or more shielding portions extend orthogonally from the plurality of second electrodes to cover the entirety of the one or more touch-insensitive first electrodes.

7. The touch sensor panel of claim 1, wherein the plurality of first electrodes are formed on a different layer than the plurality of second electrodes, the plurality of second electrodes being closer to a touch surface of the touch sensor panel than the plurality of first electrodes.

8. The touch sensor panel of claim 1, at least one of the touch-insensitive first electrodes located near an edge of the touch sensor panel.

9. The touch sensor panel of claim 1, incorporated into a hand-held computing device.

10. A method for generating compensated touch signals, comprising:

forming a plurality of first electrodes;

forming a plurality of second electrodes; and

substantially covering an entirety of one or more of the plurality of first electrodes with one or more shielding portions of the plurality of second electrodes, resulting in the one or more of the plurality of first electrodes becoming touch-insensitive first electrodes.

11. The method of claim 10, further comprising:

receiving one or more first stimulation signals at one or more of the plurality of first electrodes, different from the touch-insensitive first electrodes;

receiving one or more second stimulation signals at the one or more touch-insensitive first electrodes while receiving the one or more first stimulation signals at the one or more of the plurality of first electrodes, different from the touch-insensitive first electrodes; and

phase-shifting the one or more second stimulation signals 180 degrees from the one or more first stimulation signals.

12. The method of claim 10, further comprising capacitively coupling the plurality of second electrodes with the plurality of first electrodes to generate the compensated touch signals.

13. The method of claim 12, further comprising capacitively coupling one or more of the plurality of second electrodes with the one or more touch-insensitive first electrodes, and at a same time capacitively coupling the one or more of the plurality of second electrodes with the one or more of the plurality of first electrodes, different from the touch-insensitive first electrodes, to generate the compensated touch signals.

14. The method of claim 13, further comprising producing a fixed capacitance between the one or more of the plurality of second electrodes and the one or more touch-insensitive first electrodes.

15. The method of claim 10, further comprising orienting the plurality of first electrodes orthogonal to the plurality of second electrodes, and extending the one or more shielding portions orthogonally from the plurality of second electrodes to cover the entirety of the one or more touch-insensitive first electrodes.

16. The method of claim 10, further comprising forming the plurality of first electrodes on a different layer than the plurality of second electrodes, and locating the plurality of second electrodes closer to a touch surface of the touch sensor panel than the plurality of first electrodes.

17. The method of claim 10, further comprising locating at least one of the touch-insensitive first electrodes near an edge of the touch sensor panel.

18. A touch sensor panel for generating compensated touch signals, comprising:

a plurality of first electrodes;

a plurality of second electrodes; and

wherein the plurality of second electrodes includes one or more shielding portions for rendering one or more of the first electrodes touch-insensitive.

19. The touch sensor panel of claim 18, further comprising a capacitive sensing circuit configured for capacitively coupling an out-of-phase noise signal onto the plurality of second electrodes for canceling noise on touch signals generated on the plurality of second electrodes.

20. The touch sensor panel of claim 19, the capacitive sensing circuit further configured for combining the out-of-phase noise signals and the touch signals including a noise component on the plurality of second electrodes.