Multiple touch detection

• US 8,816,986 B1
• Filed: 06/01/2009
• Issued: 08/26/2014
• Est. Priority Date: 06/01/2008
• Status: Expired due to Fees

• Current Assignee: Monterey Research, LLC (Vector Capital Corporation)
• Original Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Inventors: Seguine, Ryan D., Park, Seok-Pyong
• Primary Examiner(s): HALEY, JOSEPH R
• Application Number:
  US12/455,413
• Time in Patent Office: 1,912 Days
• Field of Search: None
• US Class Current: 345/174
• CPC Class Codes: G06F 2203/04104 Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger
• CPC Class Codes: G06F 3/041661 using detection at multiple resolutions, e.g. coarse and fine scanning; using detection within a limited area, e.g. object tracking window
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes

Abstract

An apparatus for and method of detecting multiple presences on a touch sensor device are described.

Claims

1. A method comprising:

scanning a touch sensor array to generate sensor element signals corresponding to each of a plurality of sensor elements of the touch sensor array;

identifying a sensor window including a first signal value of a first sensor element, of the plurality of sensor elements, and a second signal value of a second sensor element adjacent to the first sensor element;

detecting a slope by determining whether the second signal value is greater than the first signal value;

shifting the sensor window according to the detected slope, said shifting causing the sensor window to include a third signal value of a third sensor element of the plurality of sensor elements, wherein the third sensor element is different from the first sensor element and different from the second sensor element; and

locating the presence of the conductive object at the touch sensor array by locating a change in slope.

2. The method of claim 1, further comprising:

when the first sensor element comprises a corner sensor element and the first signal value is greater than the second signal value, determining that the conductive object is present.

3. The method of claim 1, further comprising:

comparing the third signal value to a fourth signal value of a fourth sensor element adjacent to the third sensor element;

detecting a slope by determining whether the fourth signal value is greater than the third signal value; and

when the fourth signal value is greater than the third signal value, determining that a second conductive object is present.

4. The method of claim 3, further comprising:

determining a location of the first conductive object and of the second conductive object relative to the touch sensor array.

5. An apparatus, comprising:

a touch sensor array having a plurality of sensor elements; and

a processing device operatively coupled to the touch sensor array and configured to;

scan a touch sensor array to generate sensor element signals corresponding to each of a plurality of sensor elements of the touch sensor array;

identify a sensor window including a first signal value of a first sensor element, of the plurality of sensor elements, and a second signal value of a second sensor element adjacent to the first sensor element;

detect a slope by determining whether the second signal value is greater than the first signal value;

shift the sensor window according to the detected slope said shifting causing the sensor window to include a third signal value of a third sensor element of the plurality of sensor elements, wherein the third sensor element is different from the first sensor element and different from the second sensor element; and

locating a presence of a conductive object at the touch sensor array by locating a change in slope.

6. The apparatus of claim 5, wherein the processing device is further configured to:

when the first sensor element comprises a corner sensor element and the first signal value is greater than the second signal value, determine that the conductive object is present.

7. The apparatus of claim 5, wherein the processing device is further configured to:

compare the third signal value to a fourth signal value of a fourth sensor element adjacent to the third sensor element;

detect a slope by determining whether the fourth signal value is greater than the third signal value; and

when the fourth signal value is greater than the third signal value, determine that a second conductive object is present.

8. The apparatus of claim 5, wherein the touch sensor array comprises a one-dimensional linear slider.

9. The apparatus of claim 5, wherein the touch sensor array comprises a radial slider.

10. The apparatus of claim 5, wherein the touch sensor array comprises a two-dimensional touch-sensor pad.

11. The apparatus of claim 10, wherein the touch-sensor pad comprises a hexagon-based tri-axial sensor layout.

12. The apparatus of claim 11, wherein the touch sensor array comprises a liquid crystal display (LCD) sensing device.

13. The apparatus of claim 10, wherein the touch sensor array is configured for self-capacitance sensing.

14. The apparatus of claim 10, wherein the touch sensor array is configured for mutual-capacitance sensing.

15. A method comprising:

determining a slope based on compared signal values of sensor elements within a sensor window including a first sensor element, of a plurality of sensor elements in a touch sensor array, and a second sensor element in the touch sensor array adjacent to the first sensor element;

shifting the sensor window according to determined slope, said shifting causing the sensor window to include a third sensor element of the plurality of sensor elements, wherein the third sensor element is different from the first sensor element and different from the second sensor element; and

locating the presence of the conductive object at the touch sensor array by locating a change in slope.

16. The method of claim 15, wherein determining the presence of the conductive object comprises:

detecting the slope by determining whether the second signal value is greater than the first signal value.

17. The method of claim 16, wherein detecting the slope comprises:

comparing the first signal value to the second signal value.

18. The method of claim 16, wherein determining the presence of the conductive object comprises:

when the first sensor element comprises a corner sensor element and the first signal value is greater than the second signal value, determining that the conductive object is present.

19. The method of claim 18, further comprising:

comparing a third sensor value of the third sensor element to a fourth signal value of a fourth sensor element adjacent to the third sensor element; and

detecting a slope by determining whether the fourth signal value is greater than the third signal value, wherein when the fourth signal value is greater than the third signal value, a second conductive object is present.