Random scanning technique for secure transactions entered with capacitive sensor input device

• US 9,229,549 B1
• Filed: 05/29/2008
• Issued: 01/05/2016
• Est. Priority Date: 05/29/2007
• Status: Expired due to Fees

• Current Assignee: Monterey Research, LLC (Vector Capital Corporation)
• Original Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Inventors: Lee, Mark R.
• Primary Examiner(s): Eisen, Alexander
• Assistant Examiner(s): Lam, Nelson
• Application Number:
  US12/156,384
• Time in Patent Office: 2,777 Days
• Field of Search: 345173-179
• US Class Current: 1/1
• CPC Class Codes: G06F 21/83 input devices, e.g. keyboards, mice or controllers thereof
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• CPC Class Codes: G06F 3/044 by capacitive means

Abstract

A random scanning technique for secure transactions entered with a capacitive sensor input device is described.

Claims

1. A method, comprising:

scanning a plurality of sensor elements disposed in a touch-sensor device to produce a plurality of waveforms, wherein the scanning of the plurality of sensor elements is performed in a random sequence order, and the scanning detects a timing of the random sequence order, each being associated with a corresponding scanned sensor element;

detecting a change in the timing of a first waveform corresponding to a first sensor element;

mirroring the change in the timing from the first waveform to a second waveform corresponding to a second sensor element of the plurality of sensor elements; and

determining a location of a touch on the touch-sensor device based on the mirroring.

2. The method of claim 1, wherein the plurality of sensor elements comprise capacitive sensors.

3. The method of claim 2, wherein the plurality of sensor elements comprises a capacitive sensory array.

4. The method of claim 3, wherein determining a location of a touch on the touch-sensor device comprises:

detecting a presence of a conductive object on a capacitive sensor; and

producing a signal representative of the position of the conductive object in relation to the capacitive sensory array.

5. The method of claim 2, wherein a sensor element comprises a capacitive sensor button.

6. The method of claim 1, wherein determining a location of a touch on the touch-sensor device comprises detecting a change in an electrical signal associated with one of the plurality of sensor elements.

7. The method of claim 6, wherein the change in an electrical signal comprises a change in timing of a signal generated as a part of the scanning of the plurality of sensor elements.

8. The method of claim 1, further comprising:

reading information from a card; and

authenticating use of the card based upon a sequence of touches on the touch-sensor device.

9. An apparatus, comprising:

a touch-sensor device having a plurality of sensor elements; and

a processing device configured to scan the plurality of sensor elements in a random sequence order to generate a plurality of waveforms corresponding to the scan of the plurality of sensor elements and determine a location of a touch on the touch-sensor device, the processing device including an amplifier configured to mirror one or more of the waveforms of the plurality of waveforms,

wherein;

a timing of the random sequence order includes a plurality of time units, each being associated with a corresponding scanned sensor element,

a change in the timing includes a first time unit of the plurality of time units being longer than a second time unit of the plurality of time units; and

the amplifier is configured to mirror the change in the timing from a first waveform corresponding to a first sensor element of the plurality of sensor elements to a second waveform corresponding to a second sensor element of the plurality of sensor elements.

10. The apparatus of claim 9, wherein the plurality of sensor elements comprise capacitive sensors.

11. The apparatus of claim 10, wherein the plurality of sensor elements comprises a capacitive sensory array.

12. The apparatus of claim 11, wherein the processing device determines a location of a touch on the touch-sensor device by detecting a presence of a conductive object on a capacitive sensor and determining the location of the capacitive sensor in relation to the capacitive sensor array.

13. The apparatus of claim 10, wherein a sensor element comprises a capacitive sensor button.

14. The apparatus of claim 9, wherein the controller determines a location of a touch on the touch-sensor device by detecting a change in an electrical signal associated with one of the plurality of sensor elements.

15. The apparatus of claim 9, wherein the apparatus is an automated teller machine (ATM).

16. The apparatus of claim 9, wherein the apparatus is a point of sale (POS) terminal.

17. The apparatus of claim 9, further comprising:

a card reader coupled to the processing device to obtain account information from a card, wherein access to the account is authenticated by a sequence of touches on the touch-sensor device.

18. An apparatus, comprising:

means for scanning a plurality of sensor elements disposed in a touch-sensor device to generate a plurality of waveforms corresponding to the scanning of the plurality of sensor elements, wherein the scanning of the plurality of sensor elements is performed in a random sequence order, wherein the scanning detects a timing of the random sequence order including a plurality of time units, each being associated with a corresponding scanned sensor element, and a change in the timing includes a first time unit of the plurality of time units being longer than a second time unit of the plurality of time units;

means for mirroring the change in the timing from a first waveform of the plurality of waveforms corresponding to a first sensor element of the plurality of sensor elements to a second waveform of the plurality of waveforms corresponding to a second sensor element of the plurality of sensor elements; and

means for determining a location of a touch on the touch-sensor device based on the scanning.

19. The apparatus of claim 18, further comprising:

means for reading information from a card; and

means for authenticating use of the card based upon a sequence of touches on the touch-sensor device.

20. The apparatus of claim 18, wherein the plurality of sensor elements comprise capacitive sensors.