Dual Scanning with Automatic Gain Control

• US 20140043251A1
• Filed: 09/28/2012
• Published: 02/13/2014
• Est. Priority Date: 08/09/2012
• Status: Active Grant

• Current Assignee: Wacom Co Limited (Wacom)
• Original Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Inventors: Wilson, Cole, Wright, David G., Grivna, Edward
• Granted Patent: US 8,773,386 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• 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 2203/04108 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 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/041661 using detection at multiple resolutions, e.g. coarse and fine scanning; using detection within a limited area, e.g. object tracking window
• CPC Class Codes: G06F 3/04186 Touch location disambiguation
• 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 method and apparatus perform a first scan of an input device and determine that a first signal profile received through the first scan is outside a range of a reference signal profile. The method and apparatus perform a second scan of the input device responsive to the first signal profile being outside the range of the reference signal profile and use a second signal profile received through the second scan to detect a presence of an input object at least proximate to the input device.

Claims

1. A method comprising:

performing a first scan of an input device, wherein the first scan includes receiving first sensor signals from first electrodes;

determining that a first signal profile that is based on the first sensor signals is outside of a range of a reference signal profile, wherein signal profiles determined to be within the range of the reference signal profile indicate a presence of an input object;

performing a second scan of the input device responsive to the first signal profile being outside of the range of the reference signal profile, wherein the second scan includes receiving second sensor signals from second electrodes;

determining that a second signal profile that is based on the second sensor signals is within the range of the reference signal profile; and

using the second signal profile determined to be within the range of the reference signal profile to detect the presence of the input object at least proximate to the input device.

2. The method of claim 1, further comprising determining a portion of the input device upon which to perform the second scan, based on a dimension of the first signal profile.

3. The method of claim 1, further comprising determining a portion of the input device upon which to perform the second scan, based on a position of a previously detected presence of the input object.

4. The method of claim 3, wherein determining the portion based on the position of the previously detected presence of the input object includes predicting a position of the input object, wherein the predicted position is based on the position of the previously detected presence of the input object and a velocity of the input object, wherein the determined portion includes the predicted position.

5. The method of claim 1, wherein the performing of the first scan includes performing an axial scan and the performing of the second scan includes performing an all points addressable scan, wherein the input object is a stylus.

6. The method of claim 1, further comprising adjusting a gain of the second scan.

7. The method of claim 6, wherein the first electrodes and the second electrodes have at least one electrode in common.

8. An apparatus comprising:

a scanning module configured to perform a first scan of an input device, wherein the first scan includes receiving first sensor signals from first electrodes; and

a presence module coupled to the scanning module, the presence module configured to determine that a first signal profile that is based on the first sensor signals is not within a range of a reference signal profile stored in a memory, wherein the scanning module is configured to perform a second scan of the input device responsive to the determination that the first signal profile is not within the range of the reference signal profile, wherein the second scan includes receiving second sensor signals from second electrodes, and the presence module is configured to determine that a second signal profile that is based on the second sensor signals is within the range of the reference signal profile and use the second signal profile to detect a presence of an input object at least proximate to the input device.

9. The apparatus of claim 8, further comprising a portion module coupled to the scanning module, the portion module configured to determine a portion of the input device upon which the scanning module is to perform the second scan, based on a dimension of the first signal profile.

10. The apparatus of claim 8, further comprising a portion module coupled to the scanning module, the portion module configured to determine a portion of the input device upon which the scanning module is to perform the second scan, based on a position of a previously detected presence of the input object.

11. The apparatus of claim 10, further comprising a prediction module coupled to the portion module, the prediction module configured to predict a position of the input object, wherein the predicted position is based on the position of the previously detected presence of the input object and a velocity of the input object, wherein the determined portion includes the predicted position.

12. The apparatus of claim 8, wherein the scanning module is configured to excite a first number of transmit electrodes in the first scan and excite a second number of transmit electrodes in the second scan, wherein the second number of transmit electrodes is less than the first number of transmit electrodes.

13. The apparatus of claim 8, further comprising a gain adjustment module coupled to the scanning module, the gain adjustment module configured to adjust a gain of the second scan to meet a target signal to noise ratio value for the second signal profile.

14. The apparatus of claim 8, wherein the first electrodes and the second electrodes have at least one electrode in common.

15. A sensing system comprising:

a processing device; and

a touch input device coupled with the processing device, the processing device comprising;

a scanning module configured to perform a first scan of the touch input device and a second scan of the touch input device, wherein the first scan includes receiving first sensor signals from first electrodes, and the second scan includes receiving second sensor signals from second electrodes; and

a presence module coupled to the scanning module, the presence module configured to determine that a first signal profile, which is based on the first sensor signals, is not within a range of a reference signal profile stored in a memory, wherein the scanning module is configured to perform the second scan of the touch input device responsive to the determination that the first signal profile is not within the range of the reference signal profile, and the presence module is configured to use a second signal profile, which is based on the second sensor signals, to detect a presence of an input object at least proximate to the touch input device, based on the second signal profile being within the range of the reference signal profile.

16. The system of claim 15, further comprising a portion module coupled to the scanning module, the portion module configured to determine a portion of the touch input device upon which the scanning module is to perform the second scan, based on a dimension of the first signal profile.

17. The system of claim 15, further comprising a portion module coupled to the scanning module, the portion module configured to determine a portion of the touch input device upon which the scanning module is to perform the second scan, based on a position of a previously detected presence of the input object.

18. The apparatus of claim 17, further comprising a prediction module coupled to the portion module, the prediction module configured to predict a position of the detected presence, wherein the predicted position is based on the position of the previously detected presence of the input object and a velocity of the input object, wherein the determined portion includes the predicted position.

19. The system of claim 15, wherein the scanning module is configured to perform an axial scan as the first scan and an all points addressable scan as the second scan.

20. The system of claim 15, wherein the first electrodes and the second electrodes have at least one electrode in common.