Production testing of a capacitive touch sensing device

• US 8,253,425 B2
• Filed: 01/28/2008
• Issued: 08/28/2012
• Est. Priority Date: 05/08/2007
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Reynolds, Joseph K., Ramarapu, Pavan Kumar
• Primary Examiner(s): Hollington, Jermele M
• Assistant Examiner(s): ALLGOOD, ALESA M
• Application Number:
  US12/011,698
• Publication Number:
  US 20080278453A1
• Time in Patent Office: 1,674 Days
• Field of Search: 324/661, 324/662, 324/679, 324/686, 324/658, 324/678, 178/18.06, 178/19.03, 345/173, 345/174
• US Class Current: 324/658
• CPC Class Codes: G01D 3/08 with provision for safeguarding the apparatus, e.g. against abnormal operation, against breakdown
• CPC Class Codes: G01D 5/24 by varying capacitance
• CPC Class Codes: G01R 31/2829 Testing of circuits in sensor or actuator systems testing of apparatus for measuring electric or magnetic variables G01R35/00; testing of indicating or recording apparatus G01D; in airbag systems B60R21/0173; checking gas analysers G01N33/007; monitoring or fail-safe circuits for electromagnets H01F7/1844
• CPC Class Codes: H03K 17/962 Capacitive touch switches
• CPC Class Codes: H03K 2217/960705 Safety of capacitive touch and proximity switches, e.g. increasing reliability, fail-safe

Abstract

In one embodiment, a method for production testing of a capacitive touch sensing device is disclosed. In this embodiment, the present technology for production testing of a capacitive touch sensing device samples a first value corresponding to a first channel of a capacitive touch sensing device when the capacitive touch sensing device is in production. The present embodiment also samples a second value corresponding to the first channel of the capacitive touch sensing device when the capacitive touch sensing device has a self-test capacitive circuit applying a signal thereto. The present embodiment compares the first value and the second value to determine a production testing result for the first channel of the capacitive touch sensing device, wherein the sampling of the second value and the comparing the first value and the second value occur during production of the capacitive touch sensing device.

Claims

1. A method for production testing of a capacitive touch sensing device, said method comprising:

sampling a first value corresponding to a first channel of said capacitive touch sensing device when said capacitive touch sensing device is in production;

sampling a second value corresponding to said first channel of said capacitive touch sensing device when said capacitive touch sensing device has a self-test capacitive circuit applying a signal to said capacitive touch sensing device; and

comparing said first value and said second value to determine a production testing result for said first channel of said capacitive touch sensing device, wherein said sampling said second value and said comparing said first value and said second value occur during production of said capacitive touch sensing device.

2. The method as recited in claim 1 further comprising:

categorizing said capacitive touch sensing device based upon said production testing result for said first channel of said capacitive touch sensing device.

3. The method as recited in claim 1 further comprising:

utilizing said production testing result to adjust an operating parameter of said capacitive touch sensing device.

4. The method as recited in claim 3 wherein said utilizing said production testing result to adjust an operating parameter of said capacitive touch sensing device comprises utilizing said production testing result to adjust said operating parameter of said capacitive touch sensing device when said capacitive touch sensing device is in production.

5. The method as recited in claim 1 further comprising:

utilizing said production testing result to determine whether said capacitive touch sensing device meets a performance requirement.

6. The method as recited in claim 1 further comprising:

sampling a third value corresponding to a second channel of said capacitive touch sensing device when said capacitive touch sensing device is in production;

sampling a fourth value corresponding to said second channel of said capacitive touch sensing device when said capacitive touch sensing device has said self-test capacitive circuit applying a signal thereto; and

comparing said third value and said fourth value to determine a production testing result for said second channel of said capacitive touch sensing device.

7. The method as recited in claim 6 further comprising:

categorizing said capacitive touch sensing device based upon said production testing result for said first channel of said capacitive touch sensing device and said production testing result for said second channel of said capacitive touch sensing device.

8. The method as recited in claim 6 further comprising:

utilizing said production testing result for said first channel of said capacitive touch sensing device and said production testing result for said second channel of said capacitive touch sensing device to determine whether said capacitive touch sensing device meets a performance requirement.

9. The method as recited in claim 6 wherein said first channel of said capacitive touch sensing device and said second channel of said capacitive touch sensing device are sampled substantially sequentially.

10. The method as recited in claim 6 wherein said first channel of said capacitive touch sensing device and said second channel of said capacitive touch sensing device are sampled substantially concurrently.

11. The method as recited in claim 1 wherein said sampling a first value corresponding to a first channel of said capacitive touch sensing device when said capacitive touch sensing device is in production comprises:

sampling said first value when said capacitive touch sensing device does not have said self-test capacitive circuit applying said signal thereto.

12. The method as recited in claim 11 wherein said sampling said first value when said capacitive touch sensing device does not have said self-test capacitive circuit applying said signal thereto comprises:

sampling said first value when said capacitive touch sensing device has said self-test capacitive circuit applying a second signal different from said signal thereto.

13. The method as recited in claim 1 wherein said comparing said first value and said second value comprises:

relating a difference between said first value and said second value to a nominal difference.

14. The method as recited in claim 1 further comprising:

sampling a third value corresponding to said first channel of said capacitive touch sensing device when said capacitive touch sensing device does not have said self-test capacitive circuit applying said signal thereto.

15. The method as recited in claim 14 further comprising:

utilizing said third value and said second value to generate a difference value for comparison to a second nominal difference.

16. A production testing system for a capacitive touch sensing device, said production testing system comprising:

a self-test capacitive circuit configured to sample a plurality of values corresponding to a first channel of a capacitive touch sensing device when said capacitive touch sensing device is in production; and

a testing unit coupled to said self-test capacitive circuit, said testing unit configured to function cooperatively with said self-test capacitive circuit to generate a production testing result for said first channel of said capacitive touch sensing device, said testing unit further configured to compare a first value and a second value of said plurality of values to determine and generate said production testing result for said first channel of said capacitive touch sensing device.

17. The production testing system of claim 16 wherein said self-test capacitive circuit is configured to sample a plurality of values corresponding to a plurality of channels of said capacitive touch sensing device when said capacitive touch sensing device is in production.

18. The production testing system of claim 17 wherein said testing unit is configured to function cooperatively with said self-test capacitive circuit to generate a production testing result for each of said plurality of channels of said capacitive touch sensing device.

19. The production testing system of claim 17 wherein said self-test capacitive circuit is configured to sample a plurality of values corresponding to a plurality of channels of said capacitive touch sensing device substantially sequentially when said capacitive touch sensing device is in production.

20. A non-transitory computer-readable storage medium having computer readable code embodied thereon for causing a computer to perform a method for production testing of a capacitive touch sensing device, said method comprising:

receiving a first sampled value corresponding to a first channel of said capacitive touch sensing device when said capacitive touch sensing device is in production;

receiving a second sampled value corresponding to said first channel of said capacitive touch sensing device when said capacitive touch sensing device has a self-test capacitive circuit applying a signal thereto; and

determining a production testing result for said first channel of said capacitive touch sensing device by comparing said first sampled value and said second sampled value.

21. The non-transitory computer-readable storage medium as recited in claim 20 having computer readable code embodied thereon for causing said computer to:

categorize said capacitive touch sensing device based upon said production testing result for said first channel of said capacitive touch sensing device.

22. The non-transitory computer-readable storage medium as recited in claim 20 having computer readable code embodied thereon for causing said computer to:

utilize said production testing result to adjust an operating parameter of said capacitive touch sensing device.

23. The non-transitory computer-readable storage medium as recited in claim 20 having computer readable code embodied thereon for causing said computer to:

sample a first value corresponding to a second channel of said capacitive touch sensing device when said capacitive touch sensing device is in production;

sample a second value corresponding to said second channel of said capacitive touch sensing device when said capacitive touch sensing device has said self-test capacitive circuit applying a signal thereto; and

compare said first value and said second value to determine a production testing result for said second channel of said capacitive touch sensing device.

24. The non-transitory computer-readable storage medium as recited in claim 23 having computer readable code embodied thereon for causing said computer to:

categorize said capacitive touch sensing device based upon said production testing result for said first channel of said capacitive touch sensing device and said production testing result for said second channel of said capacitive touch sensing device.

25. The non-transitory computer-readable storage medium as recited in claim 23 having computer readable code embodied thereon for causing said computer to:

utilize said production testing result for said first channel of said capacitive touch sensing device and said production testing result for said second channel of said capacitive touch sensing device to determine whether said capacitive touch sensing device meets a performance requirement.