Tail Effect Correction for SLIM Pattern Touch Panels

• US 20140192027A1
• Filed: 09/26/2013
• Published: 07/10/2014
• Est. Priority Date: 02/24/2011
• Status: Active Grant

• Current Assignee: Parade Technologies, Ltd.
• Original Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Inventors: Ksondzyk, Petro, Mandziy, Vasyl, Kolych, Igor, Badaye, Massoud
• Granted Patent: US 8,866,491 B2
• Time in Patent Office: Days
• US Class Current: 345/178
• CPC Class Codes: G01N 27/22 by investigating capacitance
• CPC Class Codes: G01R 35/005 Calibrating; Standards or reference devices, e.g. voltage or resistance standards, "golden" references G01R33/0035, G01R35/002 take precedence
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• 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

Abstract

Techniques for correcting tail effect are described herein. In an example embodiment, a device comprises a sensor coupled with a processing logic. The sensor is configured to measure a plurality of measurements from a sensor array, where the measurements are representative of a conductive object that is in contact with or proximate to the sensor array. The sensor array comprises RX electrodes and TX electrodes that are interleaved without intersecting each other in a single layer on a substrate of the sensor array. The processing logic is configured to determine a set of adjustment values that correspond to a tail effect associated with the measurements, and to generate adjusted measurements based on the set of adjustment values, where the adjusted measurements correct a parasitic signal change of the tail effect.

Claims

1. A device comprising:

a sensor array comprising a plurality of receive (RX) electrodes and a plurality of transmit (TX) electrodes, wherein the plurality of RX electrodes and the plurality of TX electrodes are interleaved without intersecting each other within a touch-sensing area in a single layer on a substrate of the sensor array;

a sensor configured to measure a plurality of measurements from the sensor array, wherein the plurality of measurements are representative of a conductive object that is in contact with or proximate to the sensor array; and

a processing logic coupled with the sensor, wherein the processing logic is configured at least to;

determine a set of adjustment values that correspond to a tail effect associated with the conductive object represented by the plurality of measurements; and

generate adjusted measurements corresponding to the conductive object represented by the plurality of measurements based on the set of adjustment values, wherein the adjusted measurements correct the tail effect.

2. The device of claim 1, wherein the tail effect comprises a parasitic signal increase or a parasitic signal decrease that is caused by parasitic coupling between a primary trace of a RX electrode and a TX electrode that are affected by the conductive object, wherein the primary trace of the RX electrode is routed adjacent to the TX electrode.

3. The device of claim 2, wherein the primary trace of the RX electrode and a shaped portion of the RX electrode are disposed in the touch-sensing area of the sensor array, but the shaped portion of the RX electrode is not affected by the conductive object.

4. The device of claim 1, wherein the sensor array comprises a first non-sensing area and a second non-sensing area on opposite sides of the sensor array, with a first subset of the plurality of RX electrodes and a first subset of the plurality of TX electrodes being routed from the first non-sensing area, and a second subset of the plurality of RX electrodes and a second subset of the plurality of TX electrodes being routed from the second non-sensing area.

5. The device of claim 1, wherein the processing logic is further configured to determine location coordinates on the sensor array for the conductive object based on the adjusted measurements.

6. The device of claim 1, wherein the plurality of measurements include signal values for sensor elements formed by a particular TX electrode of the sensor array, and wherein the adjusted measurements include adjusted values corresponding to the signal values.

7. The device of claim 6, wherein in order to determine the adjusted values for the particular TX electrode, the processing logic is configured to:

compute a sum of indices of RX electrodes that form the sensor elements along the particular TX electrode;

compute a sum of the signal values for the sensor elements along the particular TX electrode;

compute a parameter value based on the sum of indices and the sum of the signal values; and

adjust each signal value of the signal values, to obtain a corresponding adjusted value, based at least on;

said each signal value, the parameter value, and an index of a corresponding RX electrode.

8. The device of claim 6, wherein the signal values, for the sensor elements formed by the particular TX electrode, are less than a tail-effect threshold value.

9. The device of claim 6, wherein the RX electrodes, which form the sensor elements along the particular TX electrode, have indices that are greater than an index of a RX electrode that forms a sensor element having a peak signal value.

10. A method comprising:

receiving a plurality of measurements that are measured from a sensor array, wherein the plurality of measurements are representative of a conductive object that is in contact with or proximate to the sensor array;

wherein the sensor array comprises a plurality of receive (RX) electrodes and a plurality of transmit (TX) electrodes, wherein the plurality of RX electrodes and the plurality of TX electrodes are interleaved without intersecting each other within a touch-sensing area in a single layer on a substrate of the sensor array;

a processing device determining a set of adjustment values that correspond to a tail effect associated with the conductive object represented by the plurality of measurements; and

generating adjusted measurements corresponding to the conductive object represented by the plurality of measurements based on the set of adjustment values, wherein the adjusted measurements correct the tail effect.

11. The method of claim 10, wherein the tail effect comprises a parasitic signal increase or a parasitic signal decrease that is caused by parasitic coupling between a primary trace of a RX electrode and a TX electrode that are affected by the conductive object, and wherein the primary trace of the RX electrode is routed adjacent to the TX electrode.

12. The method of claim 11, wherein the primary trace of the RX electrode and a shaped portion of the RX electrode are disposed in the touch-sensing area of the sensor array, but the shaped portion of the RX electrode is not affected by the conductive object.

13. The method of claim 10, further comprising determining diff signals for sensor elements of the sensor array based on the received plurality of measurements.

14. The method of claim 10, wherein:

the plurality of measurements include signal values for sensor elements formed by a particular TX electrode of the sensor array; and

the processing device determining the adjusted measurements comprises;

computing a sum of indices of RX electrodes that form the sensor elements along the particular TX electrode;

computing a sum of the signal values for the sensor elements along the particular TX electrode;

computing a parameter value based on the sum of indices and the sum of the signal values; and

adjusting each signal value of the signal values, to obtain a corresponding adjusted value, based at least on;

said each signal value, the parameter value, and an index of a corresponding RX electrode.

15. The method of claim 14, wherein the processing device determining the adjusted measurements further comprises:

selecting the signal values, for the sensor elements formed by the particular TX electrode of the sensor array, by comparing the plurality of measurements to a tail-effect threshold value.

16. The method of claim 14, wherein the processing device determining the adjusted measurements further comprises:

determining a first index of an RX electrode that forms a sensor element having a peak signal value; and

selecting the signal values, for the sensor elements formed by the particular TX electrode of the sensor array, by selecting only those signal values that are less than a tail-effect threshold value and that have indices greater than the first index.

17. The method of claim 10, further comprising determining location coordinates on the sensor array for the conductive object based on the adjusted measurements.

18. A system comprising:

a capacitive sensor array comprising a plurality of receive (RX) electrodes and a plurality of transmit (TX) electrodes, wherein the plurality of RX electrodes and the plurality of TX electrodes are interleaved without intersecting each other within a touch-sensing area in a single layer on a substrate of the capacitive sensor array;

a capacitive sensor coupled with the capacitive sensor array, the capacitive sensor configured to measure a plurality of measurements from the plurality of RX electrodes, wherein the plurality of measurements are representative of a conductive object that is in contact with or proximate to the capacitive sensor array; and

a processing logic coupled with the capacitive sensor, wherein the processing logic is configured at least to;

determine a set of adjustment values that correspond to a tail effect associated with the conductive object represented by the plurality of measurements; and

generate adjusted measurements corresponding to the conductive object represented by the plurality of measurements based on the set of adjustment values, wherein the adjusted measurements correct the tail effect.

19. The system of claim 18, wherein:

the tail effect comprises a parasitic signal increase or a parasitic signal decrease that is caused by parasitic capacitive coupling between a primary trace of a RX electrode and a TX electrode that are affected by the conductive object, wherein the primary trace of the RX electrode is routed adjacent to the TX electrode; and

the primary trace of the RX electrode and a shaped portion of the RX electrode are disposed in the touch-sensing area of the capacitive sensor array, but the shaped portion of the RX electrode is not affected by the conductive object.

20. The system of claim 18, wherein the capacitive sensor array comprises a first non-sensing area and a second non-sensing area on opposite sides of the capacitive sensor array, with a first subset of the plurality of RX electrodes and a first subset of the plurality of TX electrodes being routed from the first non-sensing area, and a second subset of the plurality of RX electrodes and a second subset of the plurality of TX electrodes being routed from the second non-sensing area.