Accuracy in a capacitive sense array

• US 8,903,679 B2
• Filed: 09/23/2011
• Issued: 12/02/2014
• Est. Priority Date: 09/23/2011
• Status: Active Grant

• Current Assignee: Parade Technologies, Ltd.
• Original Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Inventors: Peng, Tao, Landry, Greg
• Primary Examiner(s): LE, TOAN M
• Application Number:
  US13/241,514
• Publication Number:
  US 20130080109A1
• Time in Patent Office: 1,166 Days
• Field of Search: 702/150, 702/57, 702/81, 702/84, 702/127, 702155-158, 702/189, 702/199, 345/156, 345173-174, 345/179, 178/18.01, 178/18.03, 178/18.06, 178/19.01, 178 1903- 1904, 324/600, 324/658, 324660-661
• US Class Current: 702/150
• 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 2203/04112 Electrode mesh in capacitive digitiser: electrode for touch sensing is formed of a mesh of very fine, normally metallic, interconnected lines that are almost invisible to see. This provides a quite large but transparent electrode surface, without need for ITO or similar transparent conductive material
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• 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
• CPC Class Codes: G06F 3/0448 Details of the electrode shape, e.g. for enhancing the detection of touches, for generating specific electric field shapes, for enhancing display quality
• CPC Class Codes: H03K 17/962 Capacitive touch switches
• CPC Class Codes: H03K 2017/9602 characterised by the type or shape of the sensing electrodes

Abstract

A capacitive sense array configured to improve accuracy in detecting a presence of a conductive object is described. In one embodiment the capacitive sense array includes a first set of sense elements including a plurality of sub-sections and a second set of sense elements including a plurality of sub-sections such that the plurality of sub-sections of one sense element of the first set straddle at least one of the plurality of sub-sections of at least two of the sense elements of the second set. The straddle as defined in the present invention includes shifting and interleaving sub-section of one sense element with the sub-sections of at least two sense elements adjacent to the one sense element.

Claims

1. A capacitive sense array comprising:

a first set of sense elements comprising a first sense element comprising a plurality of first sub-sections; and

a second set of sense elements comprising a second sense element comprising a plurality of second sub-sections and a third sense element comprising a plurality of third sub-subsections, wherein the plurality of first sub-sections straddle at least one of the plurality of second sub-sections and at least one of the plurality of third sub-sections.

2. The capacitive sense array of claim 1, wherein the first set of sense elements and the second set of sense elements are disposed on a first longitudinal axis of the capacitive sense array to detect a conductive object proximate to the capacitive sense array in a single dimension.

3. The capacitive sense array of claim 1, wherein the first set of sense elements and the second set of sense elements are disposed on a first longitudinal axis of the capacitive sense array to detect a conductive object proximate to the capacitive sense array in multiple dimensions.

4. The capacitive sense array of claim 1, wherein the first element comprises three first sub-sections, the second sense element comprise three second sub-sections and the third sense element comprises three third sub-sections, wherein the first, second, and third sub-sections are substantially elongate in shape.

5. The capacitive sense array of claim 1, further comprising:

a third set of sense elements, wherein the first set of sense elements and the second set of sense elements are disposed on a first longitudinal axis of the capacitive sense array and the third set of sense elements are disposed on a second longitudinal axis of the capacitive sense array to detect a conductive object proximate to the capacitive sense array in two dimensions, wherein the second longitudinal axis is substantially perpendicular to the first longitudinal axis.

6. The capacitive sense array of claim 1, further comprising:

a third set of sense elements comprising a fourth sense element comprising a plurality of fourth sub-sections; and

a fourth set of sense elements comprising a fifth sense element comprising a plurality of fifth sub-sections and a sixth sense element comprising a plurality of sixth sub-sections, wherein the plurality of fourth sub-sections straddle at least one of the plurality of fifth sub-sections and at least one of the plurality of sixth sub-sections.

7. The capacitive sense array of claim 6, wherein the first set of sense elements and the second set of sense elements are disposed in a first layer of the capacitive sense array and the third set of sense elements and the fourth set of sense elements are disposed in a second layer of the capacitive sense array.

8. A system comprising:

a capacitive sense array comprising;

a first set of sense elements comprising a first sense element comprising a plurality of first sub-sections; and

a second set of sense elements comprising a second sense element comprising a plurality of second sub-sections and a third sense element comprising a plurality of third sub-sections, wherein the plurality of first sub-sections straddle at least one of the plurality of second sub-sections and at least one of the plurality of third sub-sections; and

a processing device coupled to the capacitive sense array, the processing device to detect a conductive object proximate to the capacitive sense array.

9. The system of claim 8, wherein the first set of sense elements and the second set of sense elements are disposed on a first longitudinal axis of the capacitive sense array to detect a conductive object proximate to the capacitive sense array in a single dimension.

10. The system of claim 8, wherein the first set of sense elements and the second set of sense elements are disposed on a first longitudinal axis of the capacitive sense array to detect a conductive object proximate to the capacitive sense array in multiple dimensions.

11. The system of claim 8, wherein the first sense element comprises three first sub-sections, the second sense element comprises three second sub-sections, and the third sense element comprises three third sub-sections, wherein the first, second, and third sub-sections are substantially elongate in shape.

12. The system of claim 8, the capacitive sense array further comprising:

a third set of sense elements, wherein the first set of sense elements and the second set of sense elements are disposed on a first longitudinal axis of the capacitive sense array and the third set of sense elements are disposed on a second longitudinal axis of the capacitive sense array to detect a conductive object proximate to the capacitive sense array in two dimensions, wherein the second longitudinal axis is substantially perpendicular to the first longitudinal axis.

13. The system of claim 8, the capacitive sense array further comprising:

a third set of sense elements comprising a fourth sense element comprising a plurality of fourth sub-sections; and

a fourth set of sense elements comprising a fifth sense element comprising a plurality of fifth sub-sections and a sixth sense element comprising a plurality of sixth sub-sections, wherein the plurality of fourth sub-sections straddle at least one of the plurality of fifth sub-sections and at least one of the plurality of sixth sub-sections.

14. The system of claim 13, wherein the first set of sense elements and the second set of sense elements are disposed in a first layer of the capacitive sense array and the third set of sense elements and the fourth set of sense elements are disposed in a second layer of the capacitive sense array.

15. A method comprising:

computing, by a processing device, a first set of coordinate values of a touch location on a first set of sense elements, wherein the first set of sense elements comprises a first sense element comprising a plurality of first sub-sections; and

computing, by the processing device, a second set of coordinate values of the touch location on a second set of sense elements, wherein the second set of sense elements comprises a second sense element comprising a plurality of second sub-sections and a third sense element comprising a plurality of third sub-sections, wherein the plurality of first sub-sections straddle at least one of the plurality of second sub-sections and at least one of the plurality of third sub-sections.

16. The method of claim 15, wherein the first set of coordinate values comprises first X-coordinate values and first Y-coordinate values and the second set of coordinate values comprise second X-coordinate values and second Y-coordinate values.

17. The method of claim 16, further comprising:

averaging the first Y-coordinate values; and

averaging the second Y-coordinate values.

18. A method comprising:

measuring, by a processing device, a first set of mutual capacitance values on a first set of sense elements, wherein the first set of sense elements comprises a first sense element comprising a plurality of first sub-sections; and

measuring, by the processing device, a second set of mutual capacitance values on a second set of sense elements, wherein the second set of sense elements comprises a second sense element comprising a plurality of second sub-sections and a third sense element comprising a plurality of third sub-sections, wherein the plurality of first sub-sections straddle at least one of the plurality of the second sub-sections and at least one of the plurality of third sub-sections.

19. The method of claim 18, further comprising:

computing a first set of coordinate values of a touch location using the first set of mutual capacitance values; and

computing a second set of coordinate values of the touch location using the second set of mutual capacitance values.

20. The method of claim 19, further comprising:

averaging the first set of coordinate values; and

averaging the second set of coordinate values.