Cancelling induced currents in a touch sensing device having an embedded near field communication antenna

• US 9,268,452 B2
• Filed: 01/13/2015
• Issued: 02/23/2016
• Est. Priority Date: 07/07/2011
• Status: Active Grant

• Current Assignee: Cirque Corporation
• Original Assignee: Cirque Corporation
• Inventors: Paulsen, Keith L.
• Primary Examiner(s): Abdin, Shaheda
• Application Number:
  US14/596,063
• Publication Number:
  US 20150130765A1
• Time in Patent Office: 406 Days
• US Class Current: 1/1
• 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 3/044 by capacitive means
• CPC Class Codes: G06F 3/046 by electromagnetic means
• CPC Class Codes: G09G 5/00 Control arrangements or circuits for visual indicators common to cathode-ray tube indicators and other visual indicators image data processing or generation, in general G06T
• CPC Class Codes: H01Q 1/22 by structural association with other equipment or articles

Abstract

A method and system for enabling a near field communication antenna to be disposed adjacent to electrodes of a touch sensing device, the near field communication antenna being operated, and the magnetic field inductance and electric field coupling between the electrodes and the near field communication antenna being minimized in order to substantially reduce or eliminate induced currents on the electrodes.

Claims

1. A method for reducing induced current in electrodes of a touch sensing device that is operating adjacent to a near field communication antenna, said method comprising:

1) providing a plurality of electrodes that form a sensing area used in a touch sensing device;

2) providing a near field communication antenna disposed adjacent to the plurality of electrodes; and

3) reducing induced current in the plurality of electrodes caused by operation of the near field communication antenna by configuring the electrodes to reduce the effect of electromagnetic fields generated by the near field communication antenna by arranging the plurality of electrodes to form the sensing area having a series of parallel rows of electrodes extending from a top edge to a bottom edge of the sensing area, each of the plurality of electrodes being electrically separate from each other, each of the plurality of electrodes following a first path that is beginning at a first edge and terminating at an opposite second edge of the sensing area; and

4) increasing a length of at least one of the plurality of electrodes that is affected by the electromagnetic fields by increasing the length beginning from the second edge and extending back towards the first edge along a second path that is parallel to the first path to thereby reduce current that is induced in the at least one of the plurality of electrodes.

2. The method as defined in claim 1 wherein the method further comprises increasing the length of the plurality of electrodes that are nearest to the top edge and the bottom edge of the sensing area because these electrodes will be most affected by the electromagnetic fields.

3. The method as defined in claim 2 wherein the method further comprises increasing the length of any of the plurality of electrodes that are having currents induced in them by the electromagnetic fields to thereby reduce induced currents in all of the plurality of electrodes.

4. The method as defined in claim 1 wherein the method further comprises reducing the induced current such that the induced current in the electrodes is substantially canceled.

5. The method as defined in claim 1 wherein the method further comprises forming the near field communication antenna as at least one loop that is disposed around an outer edge of the sensing area.

6. The method as defined in claim 5 wherein the method further comprises disposing the near field communication antenna in a plane that is substantially parallel to a plane of the plurality of electrodes.

7. The method as defined in claim 1 wherein the method further comprises arranging the plurality of electrodes to form a sensing area having a plurality of concentrically aligned electrode loops, the loops all being electrically open at a first location, and having a connection to touch sensing circuitry at an opposite second location, each of the electrode loops thereby having two arms of substantially equal length, the induced current in a first arm of each of the plurality of concentrically aligned electrode loops being equal and opposite to the induced current in a second arm of each of the plurality of concentrically aligned electrode loops to thereby result in a reduced induced current in each of the plurality of concentrically aligned electrode loops.

8. A system for reducing induced current in electrodes of a touch sensing device that is operating adjacent to a near field communication antenna, said system comprised of:

a plurality of electrodes that form a sensing area used in a touch sensing device;

a near field communication antenna disposed adjacent to the plurality of electrodes, the plurality of electrodes being configured so as to reduce the effect of electromagnetic fields generated by the near field communication antenna and thereby reducing induced current in the plurality of electrodes caused by operation of the near field communication antenna;

a series of parallel rows of the plurality of electrodes extending from a top edge to a bottom edge of a sensing area, each of the plurality of electrodes being electrically separate from each other, each of the plurality of electrodes following a first path that is beginning at a first edge and terminating at an opposite second edge of the sensing area; and

extending a length of at least one of the plurality of electrodes that is affected by the electromagnetic fields by increasing the length beginning from the second edge and extending back towards the first edge along a second path that is parallel to the first path to thereby reduce current that is induced in the at least one of the plurality of electrodes.

9. The system as defined in claim 8 wherein the system is further comprised of increased lengths of the plurality of electrodes that are nearest to the top edge and the bottom edge of the sensing area because these electrodes will be most affected by the electromagnetic fields.

10. The system as defined in claim 9 wherein the system further comprised of increased lengths of any of the plurality of electrodes that are having currents induced in them by the electromagnetic fields to thereby reduce induced currents in all of the plurality of electrodes.

11. The system as defined in claim 8 wherein the system is further comprised of the near field communication antenna formed as at least one loop that is disposed around an outer edge of the sensing area.

12. The system as defined in claim 8 wherein the system is further comprised of a plurality of concentrically aligned electrode loops forming a sensing area, the loops all being electrically open at a first location, and having a connection to touch sensing circuitry at an opposite second location, each of the plurality of concentrically aligned electrode loops thereby having two arms of substantially equal length, the induced current in a first arm of each of the plurality of concentrically aligned electrode loops being equal and opposite to the induced current in a second arm of each of the plurality of concentrically aligned electrode loops to thereby result in a reduced induced current in each of the plurality of concentrically aligned electrode loops.