Classifying input objects interacting with a capacitive button

• US 9,588,629 B2
• Filed: 11/19/2015
• Issued: 03/07/2017
• Est. Priority Date: 06/24/2014
• Status: Active Grant

• Current Assignee: Wacom Co Limited (Wacom)
• Original Assignee: Synaptics Incorporated
• Inventors: Jordan, Joel C., Schwartz, Adam L.
• Primary Examiner(s): Cheng, Joe H
• Application Number:
  US14/946,742
• Publication Number:
  US 20160077636A1
• Time in Patent Office: 474 Days
• US Class Current: 1/1
• CPC Class Codes: G01B 2210/58 Wireless transmission of information between a sensor or probe and a control or evaluation unit
• CPC Class Codes: G01B 7/003 for measuring position, not involving coordinate determination coordinate measuring G01B7/004
• 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 2203/04106 Multi-sensing digitiser, i.e. digitiser using at least two different sensing technologies simultaneously or alternatively, e.g. for detecting pen and finger, for saving power or for improving position detection
• CPC Class Codes: G06F 2203/04111 Cross over in capacitive digitiser, i.e. details of structures for connecting electrodes of the sensing pattern where the connections cross each other, e.g. bridge structures comprising an insulating layer, or vias through substrate
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04162 for exchanging data with external devices, e.g. smart pens, via the digitiser sensing hardware
• CPC Class Codes: G06F 3/0442 using active external devices, e.g. active pens, for transmitting changes in electrical potential to be received by the digitiser
• 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

Abstract

Embodiments of the invention generally provide an input device that includes a zero-dimensional button that detects whether an input object is proximate to a sensing region. However, different input objects may provide similar responses which may prevent the input device from accurately determining whether the user actually intended to activate the button. In one embodiment, the input device drives a capacitive sensing signal onto a sensor electrode in the capacitive button and measures at least two resulting signals. The input device then derives capacitance values based on the two resulting signals and uses a ratio between the capacitance values to classifying the interaction with the input object. This ratio enables the input device to distinguish between events that have similar capacitive responses and would otherwise be indistinguishable if only one resulting signal were measured.

Claims

1. An input device, comprising:

a first plurality of sensor electrodes overlapping a display;

a second plurality of sensor electrodes;

a processing system communicatively coupled to the first and second plurality of sensor electrodes, the processing system configured to;

operate the first plurality of sensor electrodes to detect positional information for an input object in a first sensing region overlapping the display; and

operate the second plurality of sensor electrodes to detect a presence of the input object in a second sensing region by;

driving a capacitive sensing signal to detect the input object onto a first electrode and a second electrode of the second plurality of sensor electrodes,

receiving a first resulting signal from the first electrode and a second resulting signal from the second electrode of the second plurality of sensor electrodes, and

determining, based on a ratio between the first and second resulting signals, whether the input object is at least one of (i) contacting the second sensing region and (ii) hovering over the second sensing region.

2. The input device of claim 1, wherein at least a subset of the first plurality of sensor electrodes are used for updating the display.

3. The input device of claim 2, wherein the processing system is further configured to operate the display using at least the subset of the first plurality of sensor electrodes.

4. The input device of claim 1, wherein the processing system is configured to:

determine that the input object is contacting the second sensing region if (i) the ratio satisfies a first predetermined threshold and (ii) the first resulting signal satisfies a second predetermined threshold.

5. The input device of claim 1, wherein the processing system is further configured to:

determine that the input object contacting the second sensing region is a stylus based on (i) the ratio satisfying a first predetermined threshold and (ii) the first resulting signal satisfying a second predetermined threshold; and

determine that the input object contacting the second sensing region is a finger based on the first resulting signal satisfying a third predetermined threshold greater than the second predetermined threshold.

6. The input device of claim 1, wherein the first sensing region detects the positional information of the input object in at least two dimensions and the second sensing region does not overlap the display.

7. The input device of claim 1, wherein in response to the determination that the input object is contacting the second sensing region activating a function associated with the second sensing region.

8. The input device of claim 1, wherein the processing system is further configured to determine motion of the input object relative to the first and second electrodes based on changes in the first and second resulting signals over time.

9. The input device of claim 1, wherein the processing system is configured to determine positional information for the input object in the first sensing region by performing at least one of transcapacitive and absolute capacitive sensing using the first plurality of sensor electrodes.

10. The input device of claim 1, wherein at least one sensor electrode of the first plurality of sensor electrodes and at least one sensor electrode of the second plurality of sensor electrodes are ohmically coupled.

11. A processing system for an input device comprising a first plurality of sensor electrodes overlapping a display and a second plurality of sensor electrodes, the processing system comprising:

a sensor module configured to operate the first plurality of sensor electrodes to detect positional information for an input object in a first sensing region overlapping the display and to operate the second plurality of sensor electrodes to detect a presence of the input object in a second sensing region overlapping the second plurality of sensor electrodes, the sensor module configured to;

drive a capacitive sensing signal to detect the input object onto a first electrode and a second electrode of the second plurality of sensor electrodes, and

receive a first resulting signal from the first electrode and a second resulting signal from the second electrode of the second plurality of sensor electrodes; and

a determination module configured to determine whether the input object is contacting the second sensing region based on a ratio between the first and second resulting signals.

12. The processing system of claim 11, further comprising an operation module for updating the display.

13. The processing system of claim 12, wherein at least a subset of the first plurality of sensor electrodes are used for updating the display.

14. The processing system of claim 12, wherein in response to the determination that the input object is contacting the second sensing region, the operation module is further configured to activate a function associated with the second sensing region.

15. The processing system of claim 11, wherein the determination module is configured to determine that the input object is a stylus contacting the second sensing region based on (i) the ratio satisfying a first predetermined threshold and (ii) the first resulting signal satisfying a second predetermined threshold.

16. The processing system of claim 15, wherein the determination module is configured to determine that the input object is a finger contacting the second sensing region based on the first resulting signal satisfying a third predetermined threshold greater than the second predetermined threshold.

17. The processing system of claim 11, wherein the determination module is further configured to determine motion of the input object relative to the one or more sensor electrodes based on changes in the first and second resulting signals over time.

18. The processing system of claim 11, wherein the sensor module is configured to perform at least one of transcapacitive and absolute capacitive sensing using the first plurality of sensor electrodes.

19. An electronic system comprising:

a display;

a first plurality of sensor electrodes overlapping the display;

a second plurality of sensor electrodes;

a processing system communicatively coupled to the first and second plurality of sensor electrodes, the processing system configured to;

operate the first plurality of sensor electrodes to detect positional information for an input object in a first sensing region overlapping the display; and

operate the second plurality of sensor electrodes to detect a presence of the input object in a second sensing region by;

driving a capacitive sensing signal to detect the input object onto first and second electrodes of the second plurality of sensor electrodes,

receiving a first resulting signal from the first electrode and a second resulting signal from the second electrode, and

determining, based on a ratio between the first and second resulting signals, whether the input object is at least one of contacting the second sensing region and hovering over the second sensing region.

20. The electronic system of claim 19, wherein the processing system is further configured to operate the display using at least a subset of the first plurality of sensor electrodes.