CHANNEL AGGREGATION FOR OPTIMAL STYLUS DETECTION

• US 20140267070A1
• Filed: 03/14/2013
• Published: 09/18/2014
• Est. Priority Date: 03/14/2013
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: SHAHPARNIA, Shahrooz, White, Kevin J., Agarwal, Manu
• Granted Patent: US 10,459,546 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 3/03545 Pens or stylus
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/046 by electromagnetic means

Abstract

A touch input device configured to detect stylus signals generated by an external stylus is provided. The touch input device includes a plurality of stylus signal detectors that receive at its input a combination of stylus receive channels that are combined in a manner to minimize noise while at the same time keeping the stylus signal strength uniform independent of the position of the stylus on the device.

Claims

1. A stylus detection apparatus for detecting contacts from a stylus, the apparatus comprising:

a touch sensor panel comprising a plurality of electrodes, each electrode configured to receive and transmit one or more signals from a stylus;

a channel aggregator configured to combine the signals transmitted by the plurality of electrodes to create a plurality of aggregated signals; and

one or more stylus signal detectors, each detector configured to receive one of the aggregated signals of the plurality of aggregated signals from the channel aggregator and determine a presence and signal strength of a stylus signal based on the received signal.

2. The apparatus of claim 1, wherein the channel aggregator is configured to separate one or more signals transmitted by the plurality of electrodes into a first group, and further configured to sum the one or more signals of the first group to generate an aggregated signal.

3. The apparatus of claim 2, wherein the one or more of the electrodes of the first group are chosen such that a detected signal strength of the stylus is uniform and independent of the stylus'"'"' position on the touch sensor panel.

4. The apparatus of claim 2, wherein the channel aggregator is further configured to separate the one or more signals transmitted by the plurality of electrodes into a second group, and further configured to subtract the one or more signals from the aggregated signal.

5. The apparatus of claim 4, wherein the one or more of the electrodes of the second group of the electrodes are chosen such that a noise signal transmitted by second group of electrodes is correlated to a noise signal transmitted by the first group of electrodes.

6. The apparatus of claim 4, wherein the first group and the second group are mutually exclusive.

7. The apparatus of claim 1, wherein a number of the stylus signal detectors is based in part on a spatial correlation of a plurality of noise signals transmitted on the plurality of electrodes of the touch sensor panel.

8. A method for detecting contacts from a stylus signal, the method comprising:

receiving one or more stylus signals on a plurality of electrodes of a touch sensor panel;

combining the signals transmitted by the plurality of electrodes to create a plurality of aggregated signals; and

inputting the one more aggregated signals into one more stylus signal detectors, each detector configured to receive one of the aggregated signals of the plurality of aggregated signals from the channel aggregator and determine the presence and signal strength of a stylus signal based on the received signal.

9. The method of claim 8, wherein combining the signals includes separating the one or more signals transmitted by the plurality of electrodes into a first group and summing the one more signals of the first group to generate an aggregated signal.

10. The method of claim 9, further comprising choosing the one or more of the electrodes of the first group such that a detected signal strength of the stylus is uniform and independent of the stylus'"'"' position on the touch sensor panel.

11. The method of claim 9, wherein combining the signals further includes separating the one or more signals transmitted by the plurality of electrodes into a second group, and subtracting the one or more signals from the aggregated signal.

12. The method of claim 8, further comprising choosing the one or more electrodes of the second group of electrodes such that a noise signal transmitted by second group of electrodes is correlated to a noise signal transmitted by the first group of electrodes.

13. The method of claim 11, wherein the first group and the second group are mutually exclusive.

14. The method of claim 8, wherein a number of stylus signal detectors is based in part on the spatial correlation of a plurality of noise signals transmitted on the plurality of electrodes of the touch sensor panel.

15. A non-transitory computer readable storage medium having stored thereon a set of instructions for detecting contacts from a stylus signal that when executed by a processor causes the processor to:

receive one or more stylus signals on a plurality of electrodes of a touch sensor panel;

combine the signals transmitted by the plurality of electrodes to create a plurality of aggregated signals; and

input the one more aggregated signals into one more stylus signal detectors, each detector configured to receive one of the aggregated signals of the plurality of aggregated signals from the channel aggregator and determine the presence and signal strength of a stylus signal based on the received signal.

16. The non-transitory computer readable storage medium of claim 15, wherein combining the signals includes separating the one or more signals transmitted by the plurality of electrodes into a first group and summing the one more signals of the first group to generate an aggregated signal.

17. The non-transitory computer readable storage medium of claim 16, wherein the processor is further caused to choose the one or more of the electrodes of the first group such that a detected signal strength of the stylus is uniform and independent of the stylus'"'"' position on the touch sensor panel.

18. The non-transitory computer readable storage medium of claim 16, wherein combining the signals further includes separating the one or more signals transmitted by the plurality of electrodes into a second group, and subtracting the one or more signals from the aggregated signal.

19. The non-transitory computer readable storage medium of claim 15, wherein the processor is further caused to choose the one or more electrodes of the second group of electrodes such that a noise signal transmitted by second group of electrodes is correlated to a noise signal transmitted by the first group of electrodes.

20. The non-transitory computer readable storage medium of claim 18, wherein the first group and the second group are mutually exclusive.

21. The non-transitory computer readable storage medium of claim 15, wherein a number of stylus signal detectors is based in part on the spatial correlation of a plurality of noise signals transmitted on the plurality of electrodes of the touch sensor panel.