Discriminating among activation of multiple buttons

• US 8,125,441 B2
• Filed: 11/19/2007
• Issued: 02/28/2012
• Est. Priority Date: 11/20/2006
• Status: Expired due to Fees

• 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:
  US11/986,255
• Publication Number:
  US 20080143671A1
• Time in Patent Office: 1,562 Days
• Field of Search: 345/22, 345/156, 345173-177, 345168-169, 178 1801- 2004, 341 20- 33
• 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 of discrimination among activation of multiple capacitive sensor buttons in close proximity to each other is described.

Claims

1. A method of discriminating a selection from among a plurality of pressed buttons, comprising:

determining whether a first button of the plurality of pressed buttons has a first activation signal value above a presence threshold;

determining whether a second button of the plurality of pressed buttons has a second activation signal value above the presence threshold;

calculating a difference value between the first activation signal value and the second activation signal value; and

if both the first and second activation signal values are above the presence threshold and the difference value is above a difference threshold;

determining which of the first activation signal value and the second activation signal value is a greater value; and

triggering a respective operation associated with either the first button or the second button determined to have the greater signal activation value.

2. The method of claim 1, further comprising:

if the difference value is below the difference threshold, omitting triggering of the respective operation associated with either the first button or the second button.

3. The method of claim 1, further comprising:

assigning a priority to each of the operations associated with the plurality of buttons; and

triggering the respective operation associated with either the first button or the second button having a greater priority with respect to each other.

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

5. The method of claim 1, wherein calculating the difference value between the first activation signal value and the second activation signal value comprises calculating a percentage using the first activation signal value to the second activation signal value.

6. The method of claim 1, wherein the first and second activation signals values 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 first activation signal value is a first difference count comprising a first raw count minus a baseline count, and wherein the 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, the first difference count plus the second difference count.

12. The method of claim 1, wherein the plurality of pressed buttons comprise capacitive sensors.

13. The method of claim 8, wherein each of the plurality of pressed buttons comprises a capacitive sensor having a substantially oval shape and wherein the difference value is the first difference count minus a first constant, divided by, the second difference count minus a second constant.

14. The method of claim 8, wherein each of the plurality of pressed buttons comprises a capacitive sensor having a substantially oval shape and wherein the difference value is the first difference count minus the second difference count, divided by, the first difference count plus 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:

determining whether a first button of the plurality of pressed buttons has a first activation signal value above a presence threshold;

determining whether a second button of the plurality of pressed buttons has a second activation signal value above the presence threshold;

calculating a difference value between the first activation signal value and the second activation signal value; and

if both the first and second activation signal values are above the presence threshold and the difference value is above a difference threshold;

determining which of the first activation signal value and the second activation signal value is a greater value; and

triggering a respective operation associated with either the first button or the second button determined to have the greater signal activation 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 of the respective operation associated with either the first button or the second button.

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 each of the operations associated with the plurality of buttons; and

triggering the respective operation associated with either the first button or the second button having a greater priority with respect to each other.

18. An apparatus, comprising:

a first touch sensor button configured to receive a first activation signal representative of the presence of a conductive object;

a second touch sensor button configured to receive a second activation signal representative of the presence of the conductive object; and

a processing device coupled with the first and second touch sensor buttons, the processing device to receive the first and second activation signals and, if both the first and second activation signals are above a presence threshold and a difference between the first and second activation signals is above a difference threshold;

to determine which of the first activation signal and the second activation signal has a greater value; and

to trigger a respective operation associated with either the first touch sensor button or the second touch sensor button determined to have the greater value.

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

a relaxation oscillator coupled with the first and second touch sensor buttons, wherein the relaxation oscillator comprises;

a current source to provide a charge current to the first and second touch sensor buttons;

a selection circuit coupled to first and second touch sensor buttons and the current source, wherein the selection circuit is configured to sequentially select one of the first and second touch sensor buttons to provide the charge current and to measure the capacitance of each of the first and second touch sensor buttons;

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 the presence threshold; and

a reset switch coupled to the comparator, current source, and 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 or a period of a relaxation oscillator output received from the relaxation oscillator.

20. The apparatus of claim 19, wherein the first and second touch sensor buttons are adjacent each other on a touch sensor panel, and wherein each of the first and second touch sensor buttons has a substantially oval shape.