TOUCH SCAN MODES DURING DEVICE CHARGING

• US 20160062494A1
• Filed: 09/02/2014
• Published: 03/03/2016
• Est. Priority Date: 09/02/2014
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: SHIH, David H.C., BOKMA, Louis W., ZUBER, Wesley W.
• Granted Patent: US 10,203,803 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• 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 3/0443 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

Abstract

Touch scan modes for touch sensitive devices during device charge is disclosed. To prevent adverse effects to the touch sensor panel due to inductive noise while the device is charging, the touch controller can switch to a touch scan mode (i.e., power charging touch mode) that can cancel or reduce noise from the touch scan or touch image. Power charging touch modes can include low noise frequency selection, increased number of touch samples employed to calculate an average, and simultaneous sampling. In some examples, a power charging touch mode can be different from a normal touch scan mode (i.e., a touch scan mode when the device is not charging). With the one or more power charging touch modes, false touch readings, erroneous touch location identification, and/or undetected touches can be eliminated or reduced.

Claims

1. A method for scanning a touch sensor panel in a device, comprising:

scanning the touch sensor panel in a non-charging scan mode;

receiving a first indication that the device is operatively coupled to a charger; and

responsive to the first indication, switching to a charging scan mode different from the non-charging scan mode, wherein the charging scan mode comprises dynamically changing a length of sample time during a touch scan.

2. The method of claim 1, further comprising:

sampling a touch pixel in the touch sensor panel a first number of times, wherein the first number is greater than a second number, the second number being associated with the non-charging scan mode; and

averaging touch values from the sampled touch pixel.

3. The method of claim 2, wherein one or more touch values is greater than the average and one or more touch values is less than the average.

4. The method of claim 1, further comprising a center of mass calculation, the center of mass calculation comprising:

stimulating one or more touch pixels of the touch sensor panel at a same time; and

scanning the one or more touch pixels to determine a plurality of touch values.

5. The method of claim 4, further comprising:

scaling each of the plurality of touch values to form a plurality of scaled touch values;

summing the plurality of scaled touch values;

summing the plurality of touch values; and

dividing the summed scaled touch values by the summed touch values.

6. The method of claim 5, wherein scaling each of the plurality of touch values includes multiplying each of the plurality of touch values by a center of mass of the one or more touch pixels.

7. The method of claim 4, wherein a number of stimulated touch pixels is same as a number of touch pixels in the touch sensor panel.

8. The method of claim 1, wherein the first indication is received from a power supply circuit.

9. The method of claim 1, wherein the first indication is received from a circuit coupled to a power adapter.

10. The method of claim 1, further comprising:

receiving a second indication that the device is decoupled from a charger and

switching to the non-charging scan mode, when the second indication has been received.

11. A method of a first device communicating with a second device, the method comprising:

sending, to a second device, one or more touch values from sense circuitry; and

receiving, from the second device, at least one of a touch value and a center of mass location.

12. A touch sensor panel comprising:

logic configured to receive a first indication that the device is operatively coupled to a charger, wherein the logic is further configured to switch between a charging scan mode different from a non-charging scan mode, when the first indication has been received, wherein the charging scan mode comprises dynamically changing a length of sample time during a touch scan.

13. The touch sensor panel of claim 12, further comprising sense circuitry configured to sample the touch pixel in the touch sensor panel a first number of times, wherein the first number is greater than a second number, the second number being associated with the non-charging scan mode, and wherein the logic is further configured to average touch values from the sampled touch pixel.

14. The touch sensor panel of claim 13, wherein one or more touch values is greater than the average and one or more touch values is less than the average.

15. The touch sensor panel of claim 12, further comprising:

drive circuitry configured to stimulate one or more touch pixels of the touch sensor panel at a same time; and

sense circuitry configured to scan the one or more touch pixels to determine a plurality of touch values.

16. The touch sensor panel of claim 15, further comprising:

a scaler configured to scale each of the plurality of touch values to form a plurality of scaled touch values;

an adder configured to sum the plurality of scaled touch values;

an adder configured to sum the plurality of touch values; and

a divider configured to divide the summed scaled touch values by the summed touch values.

17. The touch sensor panel of claim 16, wherein the scaler is further configured to multiple each of the plurality of touch values by a center of mass of the one or more touch pixels.

18. The touch sensor panel of claim 12, wherein the first indication is received by a power supply circuit.

19. The touch sensor panel of claim 12, wherein the first indication is received from a circuit coupled to a power adapter.

20. The touch sensor panel of claim 12, wherein the logic is further configured to receive a second indication representative of a non-charge from the circuit and switch to the non-charging scan mode, when the second indication has been received.