Methods and apparatus to detect presence of an input object

• US 8,779,780 B1
• Filed: 03/30/2012
• Issued: 07/15/2014
• Est. Priority Date: 02/23/2012
• Status: Expired due to Fees

• Current Assignee: Monterey Research, LLC (Vector Capital Corporation)
• Original Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Inventors: Peterson, Jonathan R., Olson, Dana
• Primary Examiner(s): Assouad, Patrick
• Assistant Examiner(s): PRETLOW, DEMETRIUS R
• Application Number:
  US13/436,015
• Time in Patent Office: 837 Days
• Field of Search: 324/613, 324/614, 324658-690, 345156-184
• US Class Current: 324/658
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/04186 Touch location disambiguation
• CPC Class Codes: G06F 3/044 by capacitive means

Abstract

A method and apparatus use a plurality of first region values to calculate a second region value, each of the plurality of first region values reflecting sensor element activity in a corresponding region of an input module, the second region value reflecting sensor element activity of a group of the corresponding regions. The method and apparatus determine that the input object is present relative to the group of the corresponding regions if the second region value meets or exceeds a threshold presence value.

Claims

1. A method of detecting a presence of an input object, the method comprising:

using a processor and a plurality of first region values, calculating a second region value such that a signal to noise ratio of the second region value is greater than a lowest signal to noise ratio out of the plurality of first region values, each of the plurality of first region values reflecting sensor element activity in a corresponding region of an input module, the second region value reflecting sensor element activity of a group of the corresponding regions; and

determining that the input object is present relative to the group of the corresponding regions if the second region value meets or exceeds a threshold presence value.

2. The method of claim 1, wherein the calculating of the second region value includes calculating a sum of the plurality of first region values.

3. The method of claim 1, wherein the calculating of the second region value includes applying a weight factor to at least one of the plurality of first region values.

4. The method of claim 1, wherein the sensor element activity in each corresponding region of the input module includes a change in capacitance of sensor elements within each corresponding region.

5. The method of claim 1, further comprising determining a position of the input object in a coordinate system of the input module using at least one of the plurality of first region values.

6. The method of claim 5, wherein the determining of the position of the input object includes using the at least one of the plurality of first region values in a centroid calculation.

7. A sensing module comprising:

a region value module configured to generate a plurality of first region values, each of the plurality of first region values reflecting sensor element activity in a corresponding region of an input module; and

a presence detector coupled to the region value module, the presence detector configured to use the plurality of the first region values to calculate a second region value such that a signal to noise ratio of the second region value is greater than a lowest signal to noise ratio out of the plurality of first region values, the second region value reflecting sensor element activity in a group of the corresponding regions and the presence detector configured to determine that the input object is present relative to the group of corresponding regions if the second region value meets or exceeds a threshold presence value.

8. The sensing module of claim 7, wherein the presence detector is configured to calculate the second region value as a sum of the plurality of first region values.

9. The sensing module of claim 8, wherein the presence detector is configured to apply a weight factor to at least one of the plurality of first region values to calculate the second region value.

10. The sensing module of claim 7, further comprising a signal sensor configured to determine sensor activity in each corresponding region of the input module, wherein the sensor activity includes a change in capacitance of sensor elements within each corresponding region.

11. The sensing module of claim 7, further comprising a position module configured to determine a position of the input object in a coordinate system of the input module using at least one of the plurality of first region values.

12. The sensing module of claim 11, wherein the position module is configured to use the at least one of the plurality of first region values in a centroid calculation to determine the position of the input object.

13. A sensing system comprising:

a processing device; and

a capacitive sensor array coupled with the processing device, the processing device comprising a region value module configured to generate a plurality of first region values, each of the plurality of first region values reflecting sensor element activity in a corresponding region of the capacitive sensor array, the processing device comprising a presence detector coupled to the region value module, the presence detector configured to use the plurality of the first region values to calculate a second region value such that a signal to noise ratio of the second region value is greater than a lowest signal to noise ratio out of the plurality of first region values, the second region value reflecting sensor element activity in a group of the corresponding regions, the presence detector configured to determine that an input object is present relative to the group of the corresponding regions if the second region value meets or exceeds a threshold presence value.

14. The sensing system of claim 13, wherein the presence detector is configured to calculate the second region value as a sum of the plurality of first region values.

15. The sensing system of claim 14, wherein the presence detector is configured to apply a weight factor to at least one of the plurality of first region values to calculate the second region value.

16. The sensing system of claim 13, further comprising a signal sensor configured to determine sensor activity in each corresponding region of the capacitive sensor array, wherein the sensor activity includes a change in capacitance of sensor elements within each corresponding region.

17. The sensing system of claim 13, further comprising a position module configured to determine a position of the input object in a coordinate system of the capacitive sensor array using at least one of the plurality of first region values in a centroid calculation.