Ground detection for touch sensitive device

• US 10,359,884 B2
• Filed: 03/27/2017
• Issued: 07/23/2019
• Est. Priority Date: 07/16/2009
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Hotelling, Steven P., Amm, David, Lammers, Michael, Orchard, John T., King, Brian Michael, Leung, Omar S., Teoman, Deniz
• Primary Examiner(s): Shah, Priyank J
• Application Number:
  US15/470,690
• Publication Number:
  US 20170199625A1
• Time in Patent Office: 848 Days
• Field of Search: 345173-179, 178 1801- 1807, 178 1901, 178 1903- 1904, 463 37- 38
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• 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

Ground detection of a touch sensitive device is disclosed. The device can detect its grounded state so that poor grounding can be selectively compensated for in touch signals outputted by the device. The device can include one or more components to monitor certain conditions of the device. The device can analyze the monitored conditions to determine the grounding condition of the device. The device can apply a function to compensate its touch signal outputs if the device determines that it is poorly grounded. Conversely, the device can omit the function if the device determines that it is well grounded.

Claims

1. A touch sensitive device comprising:

a touch sensor panel configured to sense one or more touch signals associated with a sensed touch; and

a processor configured to;

determine one or more characteristics of a touch of a touch image based on the one or more touch signals associated with the sensed touch, wherein the one or more characteristics are a location or an orientation of the touch of the touch image;

determine whether the location or orientation of the touch of the touch image is indicative of at least one of a first grounding condition or a second grounding condition, wherein the first grounding condition is indicative of negative capacitance introduced into the device, and wherein the second grounding condition is not indicative of negative capacitance introduced into the device; and

in accordance with a determination that the location or orientation of the touch of the touch image is indicative of the first grounding condition, apply compensation to one or more touch signals having one or more negative touch output values; and

in accordance with a determination that the location or orientation of the touch of the touch image is indicative of the second grounding condition, forgo the compensation.

2. The touch sensitive device of claim 1, wherein applying the compensation to the one or more touch signals having the one or more negative touch output value comprises applying a scale factor to the function to reduce an amount of negative capacitance compensation, the scale factor being less than one.

3. The touch sensitive device of claim 2, wherein the scale factor is based on an amount of grounding of the device.

4. The touch sensitive device of claim 1, wherein the one or more characteristics of the touch of the touch image comprise location, orientation, shape, and movement of the touch image.

5. The touch sensitive device of claim 1, wherein determining that the location or orientation of the touch of the touch image is indicative of the second grounding condition comprises determining that the touch image is indicative of a user gripping the device.

6. The touch sensitive device of claim 1, wherein determining that the location or orientation of the touch of the touch image is indicative of the second grounding condition comprises determining that the touch of the touch image comprises an oval shape having an angular orientation at a lower corner of the touch image.

7. A method comprising:

sensing one or more touch signals associated with a sensed touch at a touch sensor panel of a touch sensitive device;

determining one or more characteristics of a touch of a touch image based on the one or more touch signals associated with the sensed touch, wherein the one or more characteristics are a location or an orientation of the touch of the touch image;

determining whether the location or orientation of the touch of the touch image is indicative of at least one of a first grounding condition or a second grounding condition, wherein the first grounding condition is indicative of negative capacitance introduced into the device, and wherein the second grounding condition is not indicative of negative capacitance introduced into the device; and

in accordance with a determination that the location or orientation of the touch of the touch image is indicative of the first grounding condition, applying compensation to one or more touch signals having one or more negative touch output values; and

in accordance with a determination that the location or orientation of the touch of the touch image is indicative of the second grounding condition, forgo the compensation.

8. The method of claim 7, further comprising:

applying a scale factor to the compensation to reduce an amount of negative capacitance compensation, the scale factor being less than one.

9. The method of claim 8, wherein the scale factor is based on an amount of grounding of the device.

10. The method of claim 7, wherein the one or more characteristics of the touch of the touch image comprise location, orientation, shape, and movement of the touch image.

11. The method of claim 7, determining that the location or orientation of the touch of the touch image is indicative of the second grounding condition comprises determining that the touch of the touch image is indicative of a user gripping the device.

12. The method of claim 7, wherein determining that the location or orientation of the touch of the touch image is indicative of the second grounding condition comprises determining that the touch of the touch image comprises an oval shape having an angular orientation at a lower corner of the touch image.