Discriminating among activation of multiple buttons

• US 8,537,107 B1
• Filed: 02/07/2012
• Issued: 09/17/2013
• Est. Priority Date: 11/20/2006
• Status: Active Grant

• Current Assignee: Monterey Research, LLC (Vector Capital Corporation)
• Original Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Inventors: Li, Guanghai
• Primary Examiner(s): Eisen, Alexander
• Assistant Examiner(s): Patel, Sanjiv D
• Application Number:
  US13/368,189
• Time in Patent Office: 588 Days
• Field of Search: 345173-179, 345168-169, 178 1801- 2004, 341/22, 341/33, 341/34
• US Class Current: 345/156
• CPC Class Codes: G06F 3/023 Arrangements for converting discrete items of information into a coded form, e.g. arrangements for interpreting keyboard generated codes as alphanumeric codes, operand codes or instruction codes
• 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

An apparatus and method for discrimination of activation of multiple buttons are described. To discriminate among the activations, a processing device detects multiple activated touch-sensor buttons on a touch-sensor array. The processing device determines a difference value corresponding to a difference between activation signal values for each of the activated touch-sensor buttons and compares the difference value to a difference threshold. If the difference value is above the difference threshold, the processing device determines which of the activated touch-sensor buttons has a greater activation signal value and triggers an operation associated with that touch-sensor button.

Claims

1. A method comprising:

detecting a plurality of activated touch-sensor buttons on a touch-sensor array, each of the plurality of activated touch-sensor buttons comprising an active area of the touch-sensor array including a plurality of touch-sensor elements;

determining a difference value corresponding to a difference between activation signal values for different buttons of the plurality of activated touch-sensor buttons on the touch-sensor array;

comparing the difference value to a difference threshold; and

when the difference value is above the difference threshold;

determining which of the plurality of activated touch-sensor buttons has a greater activation signal value; and

triggering an operation associated with a touch-sensor button of the plurality of activated touch-sensor buttons determined to have the greater activation signal value.

2. The method of claim 1, further comprising:

if the difference value is below the difference threshold, omitting triggering an operation associated with any of the plurality of activated touch-sensor buttons.

3. The method of claim 1, further comprising:

assigning a priority to operations associated with the plurality of activated touch-sensor buttons; and

triggering an operation associated with one of the plurality of activated touch-sensor buttons having a greater priority with respect to another of the plurality of activated touch-sensor buttons.

4. The method of claim 1, wherein determining the difference value comprises subtracting a first activation signal value and a second activation signal value.

5. The method of claim 1, wherein determining the difference value comprises calculating a percentage difference between the activation signal values for the plurality of activated touch-sensor buttons.

6. The method of claim 1, wherein the activation signal values for the plurality of activated touch-sensor buttons are digital count values.

7. The method of claim 6, wherein the difference threshold is approximately 30 counts.

8. The method of claim 6, wherein a first activation signal value is a first difference count comprising a first raw count minus a baseline count, and wherein a second activation signal value is a second difference count comprising a second raw count minus the baseline count.

9. The method of claim 8, wherein the difference value is the first difference count minus the second difference count.

10. The method of claim 8, wherein the difference value is the first difference count divided by the second difference count.

11. The method of claim 8, wherein the difference value is the first difference count divided by a sum of the first difference count and the second difference count.

12. The method of claim 1, wherein the plurality of activated touch-sensor buttons comprise capacitive sensor buttons.

13. The method of claim 8, wherein each of the plurality of activated touch-sensor buttons comprises an active area having a substantially oval shape of a capacitance sense array and wherein the difference value is the first difference count minus a first constant, divided by a difference between the second difference count and a second constant.

14. The method of claim 8, wherein each of the plurality of activated touch-sensor buttons comprises an active area having a substantially oval shape of a capacitance sense array and wherein the difference value is the first difference count minus the second difference count, divided by a sum of the first difference count and the second difference count minus a constant.

15. A non-transitory computer readable medium comprising data that, when accessed by the computer, cause the computer to perform operations comprising:

detecting a plurality of activated touch-sensor buttons on a touch-sensor array, each of the plurality of activated touch-sensor buttons comprising an active area of the touch-sensor array including a plurality of touch-sensor elements;

determining a difference value corresponding to a difference between activation signal values for different buttons of the plurality of activated touch-sensor buttons on the touch-sensor array;

comparing the difference value to a difference threshold; and

when the difference value is above the difference threshold;

determining which of the plurality of activated touch-sensor buttons has a greater activation signal value; and

triggering an operation associated with a touch-sensor button of the plurality of activated touch-sensor buttons determined to have the greater activation signal value.

16. The non-transitory computer readable medium of claim 15, wherein the data, when accessed by the computer, cause the computer to perform operations further comprising:

if the difference value is below the difference threshold, omitting triggering an operation associated with any of the plurality of activated touch-sensor buttons.

17. The non-transitory computer readable medium of claim 15, wherein the data, when accessed by the computer, cause the computer to perform operations further comprising:

assigning a priority to operations associated with the plurality of activated touch-sensor buttons; and

triggering an operation associated with one of the plurality of activated touch-sensor buttons having a greater priority with respect to another of the plurality of activated touch-sensor buttons.

18. An apparatus comprising:

a capacitive sense array comprising a plurality of capacitive sense elements, the plurality of capacitive sense elements arranged to form a plurality of touch-sensor buttons;

a processing device coupled to the capacitive sense array, the processing device to receive activation signals in response to an activation of different buttons of the plurality of touch-sensor buttons, determine a difference value corresponding to a difference between the activation signals from the different buttons, compare the difference value to a difference threshold and, when the difference value is above the difference threshold;

to determine which of the activation signals has a greater value; and

to trigger an operation associated with a touch-sensor button of the plurality of the touch sensor buttons with an activation signal determined to have the greater value.

19. The apparatus of claim 18, wherein the processing device comprises:

a relaxation oscillator coupled to the capacitive sense array, wherein the relaxation oscillator comprises;

a current source to provide a charge current to the plurality of capacitive sense elements;

a selection circuit coupled to the plurality of capacitive sense elements and the current source, wherein the selection circuit is configured to sequentially select one of the plurality of touch-sensor buttons to provide the charge current and to measure a capacitance of the plurality of capacitive sense elements;

a comparator coupled to the current source and the selection circuit, wherein the comparator is configured to compare a voltage on the selected touch-sensor button and a threshold voltage corresponding to a presence threshold; and

a reset switch coupled to the comparator, the current source, and the selection circuit, wherein the reset switch is configured to reset the charge current on the selected touch-sensor button; and

a digital counter coupled to the relaxation oscillator, wherein the digital counter is configured to count at least one of a frequency and a period of a relaxation oscillator output received from the relaxation oscillator.

20. The apparatus of claim 18, wherein each of the plurality of touch-sensor buttons comprises an active area of the capacitive sense array formed from one or more of the plurality of capacitive sense elements.