Touch button false activation suppression

• US 8,395,594 B2
• Filed: 06/10/2008
• Issued: 03/12/2013
• Est. Priority Date: 06/10/2008
• Status: Active Grant

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: Karhiniemi, Marko
• Primary Examiner(s): Nguyen, Kevin M
• Application Number:
  US12/997,373
• Publication Number:
  US 20110090169A1
• Time in Patent Office: 1,736 Days
• Field of Search: 345/173, 345/174
• US Class Current: 345/173
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/04883 for inputting data by handwriting, e.g. gesture or text
• CPC Class Codes: H03K 17/962 Capacitive touch switches
• CPC Class Codes: H03K 2017/9613 using two electrodes per touch switch
• CPC Class Codes: H03K 2217/960705 Safety of capacitive touch and proximity switches, e.g. increasing reliability, fail-safe

Abstract

A touch member (210) comprises a touch surface (20, 30) having at least two sensor electrodes (21-23) that are separated from each other on the touch surface (20, 30). Each of the sensor electrodes (21-23) have a certain signal level threshold with relation to activate/lock the touch member (210). The touch surface (20, 30) is divided into a first area and a second area each comprising at least one of the sensor electrodes (21-23). Upon touching the touch member (210) in an unlocked state, the at least two electrodes (21-23) are arranged to measure periodically a signal level received from each of the electrodes (21-23) to indicate a touch location, report periodically the touch location with respect to the first area of the touch surface (20, 30), and report the measured signal level of each of the electrodes (21-23) in the second area of the touch surface (20, 30). The controller (214) sends an instruction to select an operation state of the touch member (210) based on calculated touch location information of the reported touch location and compared signal level information of the reported measured signal level.

Claims

1. A touch member comprising

a touch surface comprising at least two electrodes that are separated from each other on the touch surface, each of the electrodes having a certain signal level threshold in order to activate the touch member, and

a first area and a second area within the touch surface, wherein the at least two electrodes, upon touching the touch member in an unlocked state, are arranged to

measure periodically a signal level received from each of the electrodes to indicate a touch location,

report periodically the touch location with respect to the first area of the touch surface,

report the measured signal level of each of the electrodes in the second area of the touch surface, and

receive instruction to select an operation state of the touch member based on calculated touch location information of the reported touch location and compared signal level information of the reported measured signal level.

2. Touch member according to claim 1, wherein the at least two electrodes are arranged to receive instruction to select an activated operation state if the calculated touch location information indicates that the touch location is within the first area and if the compared signal level information does not reach the signal level threshold of the corresponding electrode.

3. Touch member according to claim 2, wherein, in the beginning of the measurements, the measured signal level of the electrode in the second area does not reach the signal level threshold of the corresponding electrode and said measured signal level does not reach the measured signal level of an adjacent electrode in the first area.

4. Touch member according to claim 1, wherein the at least two electrodes are arranged to receive instruction to select a locked operation state if the calculated touch location information indicates that the touch location is within the second area and if the compared signal level information does not reach the signal level threshold of the corresponding electrode.

5. Touch member according to claim 1, wherein the at least two electrodes are arranged to receive instruction to select a locked operation state if the calculated touch location information indicates that the touch location is within the first area and if the compared signal level information reaches the signal level threshold of the corresponding electrode.

6. Touch member according to claim 5, wherein the measured signal level of each of the at least two electrodes reaches the signal level threshold of the corresponding electrode.

7. Touch member according to claim 5, wherein, in the beginning of the measurements, the measured signal level of the electrode in the second area reaches the signal level threshold of the corresponding electrode, and said measured signal level does not reach the measured signal level of an adjacent electrode in the first area.

8. Touch member according to claim 5, wherein, in the beginning of the measurements, the measured signal level of the electrode in the second area does not reach the measured signal level of an adjacent electrode in the first area.

9. Touch member according to claim 1, comprising electrodes arranged in concentric constellation, wherein a reference point of the constellation is defined.

10. Touch member according to claim 9, wherein the touch location is based on a distance between the reference point and the touch location, and a relative size of the touch.

11. Touch member according to claim 10, wherein the relative size of the touch relates to the measured signal level of each of the electrodes that are touched.

12. Touch member according to claim 1, wherein the signal level threshold for each of the electrodes is defined by modifying a shape of each of the electrodes in a way that a sequence of indicated touch locations form a continuous sequence of measured signal levels when the touch location moves in a certain direction.

13. Touch member according to claim 12, wherein the shape of each of the electrodes with respect to the touch surface is modified by defining a width of each of the electrodes and a width of a spacing between the adjacent electrodes or wherein the shape of each of the electrodes is modified by adding interleaved areas in the electrodes.

14. Touch member according to claim 12, wherein sequence of measured signal levels correspond to a projected capacitance of the electrodes.

15. Touch member according to claim 1, wherein a form factor of each of the electrodes is a full ring or a half ring with respect to the touch surface.

16. An electronic device comprising

at least one touch member having a touch surface comprising at least two electrodes that are separated from each other on the touch surface, each of the electrodes having a certain signal level threshold in order to activate the touch member, and having a first area and a second area within the touch surface,

the at least two electrodes, upon touching the touch member in an unlocked state, are arranged to

measure periodically a signal level received from each of the electrodes to indicate a touch location,

report periodically the touch location with respect to the first area of the touch surface, and

report the measured signal level of each of the electrodes in the second area of the touch surface,

a controller arranged to

calculate a change of the touch location based on the reported touch location to produce location information,

compare the reported measured signal level to the signal level threshold of the corresponding electrode to produce signal level information, and

select an operation state of the touch member based on received location information and signal level information.

17. Electronic device according to claim 16, further comprising a multiplexer arranged to multiplex conductors from each of the electrodes so that an average number of input/output conductors from the touch member is less than a number of the electrodes in the touch member.

18. Electronic device according to claim 16, further comprising a memory arranged to store a set of signal level thresholds for each of the at least two electrodes.

19. Electronic device according to claim 16, further comprising means for selecting the locking operation state for all the touch members of the electronic device if the controller selects the locking operation state for any of the touch member of the electronic device.

20. A method comprising

defining a certain signal level threshold to each of at least two electrodes separated from each other on a touch surface, the signal level threshold relating to activate the electrode,

upon touching the touch surface in an unlocked state, measuring a signal level from each of the at least two electrodes to indicate a touch location on the touch surface,

reporting periodically the touch location with respect to a first area of the touch surface,

reporting the measured signal level of each of the electrodes in a second area of the touch surface that excludes the first area,

calculating a change of the touch location based on the reported touch location to produce location information,

comparing the reported measured signal level to the signal level threshold of the corresponding electrode to produce signal level information, and

selecting an operation state of a touch member based on location information and signal level information.