Two-dimensional position sensor

• US 8,552,315 B2
• Filed: 09/03/2009
• Issued: 10/08/2013
• Est. Priority Date: 09/03/2009
• Status: Active Grant

• Current Assignee: Atmel Corporation (Microchip Technology Incorporated)
• Original Assignee: Atmel Corporation (Microchip Technology Incorporated)
• Inventors: Yilmaz, Esat
• Primary Examiner(s): Young, Wayne
• Assistant Examiner(s): BUTCHER, BRIAN M
• Application Number:
  US12/553,589
• Publication Number:
  US 20110048812A1
• Time in Patent Office: 1,496 Days
• Field of Search: None
• US Class Current: 178/18.06
• CPC Class Codes: G06F 3/04164 Connections between sensors and controllers, e.g. routing lines between electrodes and connection pads
• 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 3/0443 using a single layer of sensing electrodes

Abstract

A capacitive position sensor is provided having a touch-sensitive area defined by a single-layer of electrodes arranged in a pattern along two axes. The electrode pattern includes a plurality of units each occupying a portion of the touch sensitive area along one axis. Each unit has at least three lines of elongate electrodes spaced apart in the one axis and extending for a length parallel to the other axis. The three lines of elongate electrodes in each unit comprise at least one line of drive electrodes and two lines of sense electrodes or at least one line of sense electrodes and two lines of drive electrodes. Selected electrodes of each unit are arranged in interconnected groups, each group having electrodes from more than one line which have partially overlapping extents along their length.

Claims

1. A device comprising:

a first region extending along a first axis comprising a first bar shaped electrode extending along the first axis and within the first region, the first bar shaped electrode formed in a first layer of a capacitive sensor;

a second region extending along the first axis comprising at least three bar shaped electrodes formed in the first layer of the capacitive sensor and formed within the second region, each of the at least three bar shaped electrodes extending along the first axis, each of the at least three bar shaped electrodes being distinct from one another such that no electrodes are present in the first layer between the first region and the second region, the second region parallel and adjacent to the first region, the second region distinct from the first region;

a third region extending along the first axis comprising a second bar shaped electrode formed in the first layer of the capacitive sensor, the second bar shaped electrode extending along the first axis and arranged within the third region, the third region parallel and adjacent to the second region such that no electrodes are present in the first layer between the second region and the third region, the third region distinct from the first region and the second region; and

a plurality of tracks configured to selectively couple electrodes within the second region and the third region.

2. The device of claim 1 wherein the second bar shaped electrode is situated within the third region such that the second bar shaped electrode at least partially overlaps in the first axis with at least one of the at least three bar shaped electrodes within the second region.

3. The device of claim 2 wherein:

the electrodes within the second region and the third region are sense electrodes;

the first bar shaped electrode is a drive electrode and is configured to extend along the length of the at least three bar shaped electrodes; and

the device further comprises a fourth region extending along the first axis comprising a third bar shaped drive electrode formed in the first layer of the capacitive sensor extending along the first axis at a length substantially similar to the first bar shaped electrode, the fourth region parallel and adjacent to the third region, the fourth region distinct from the first, second, and third regions, the third bar shaped electrode being a drive electrode.

4. The device of claim 2 wherein each of the at least three bar shaped electrodes have substantially the same length as each other.

5. The device of claim 2 wherein the plurality of tracks:

are narrower than the electrodes within the first, second, and third regions; and

extend between electrodes within the second region and the third region to couple an electrode from the second region to an electrode from the third region that at least partially overlap in the first axis.

6. The device of claim 1 wherein:

the electrodes within the second region and the third region are drive electrodes;

the third region further comprises a third bar shaped electrode extending along the first axis and formed in the first layer of the capacitive sensor, the third bar shaped electrode distinct from the second bar shaped electrode;

the second bar shaped electrode at least partially overlaps in the first axis with a fourth electrode within the second region;

the third bar shaped electrode at least partially overlaps in the first axis with a fifth electrode within the second region, the fifth electrode within the second region different than the fourth electrode within the second region; and

the plurality of tracks comprises;

a first track configured to couple the second bar shaped electrode to the fourth electrode within the second region; and

a second track configured to couple the third bar shaped electrode to the fifth electrode within the second region.

7. The device of claim 6 wherein:

the first bar shaped electrode is a first bar shaped sense electrode configured to extend along the length of the electrodes within the second region; and

the device further comprises a fourth region extending along the first axis comprising a sixth bar shaped electrode formed in the first layer of the capacitive sensor extending along the first axis at a length substantially similar to the first bar shaped sense electrode, the fourth region parallel and adjacent to the third region, the fourth region distinct from the first, second, and third regions, the sixth bar shaped electrode being a sense electrode.

8. The device of claim 7 wherein each of the at least three bar shaped electrodes have substantially the same length as each other.

24. The device of claim 1, wherein the first bar shaped electrode, the second bar shaped electrode, and the at least three bar shaped electrodes are substantially rectangular in shape.

26. The device of claim 1, wherein the second axis is the x-axis.

9. A capacitive position sensor comprising:

a touch-sensitive area defined by a single-layer of electrodes arranged in a pattern along first and second axes in a first layer,

the pattern comprising a plurality of units each occupying a portion of the touch sensitive area along the second axis,

each of the plurality of units comprising at least three regions extending parallel to the first axis and spaced apart in the second axis such that no electrodes are present in the first layer between any two adjacent regions of the at least three regions and such that no two regions of the at least three regions comprise a common electrode in the first layer, each of the at least three regions distinct from one another,

at least one region of the at least three regions comprising a line of drive electrodes situated within a single region of the at least three regions,

each of at least two regions of the at least three regions comprising a line of sense electrodes situated within a single region of the at least three regions,

wherein the sense electrodes of each unit are arranged in groups of interconnected sense electrodes,

each of the groups comprising sense electrodes from more than one of the lines of sense electrodes coupled to one another, and

each of the groups comprising sense electrodes that have partially overlapping extents along the first axis.

10. The sensor of claim 9, wherein each unit has two lines of drive electrodes and a plurality of lines of sense electrodes arranged in between the drive electrodes along the second axis.

11. The sensor of claim 9, wherein the at least three regions of each unit are arranged such that:

a first region of the at least three regions comprises the line of drive electrodes;

a second region of the at least three regions comprises a first line of sense electrodes, the second region adjacent to the first region along the second axis; and

a third region of the at least three regions comprises a second line of sense electrodes, the third region adjacent to the second region along the second axis.

12. The sensor of claim 9, wherein the at least three regions of each unit are arranged such that:

a first region of the at least three regions comprises a first line of sense electrodes;

a second region of the at least three regions comprises the line of drive electrodes, the second region adjacent to the first region along the second axis; and

a third region of the at least three regions comprises a second line of sense electrodes, the third region adjacent to the second region along the second axis.

13. The sensor of claim 9, wherein the at least three regions of each unit comprises only two lines of sense electrodes and at least one line of drive electrodes.

14. The sensor of claim 9, wherein each line of sense electrodes of each unit comprises at least three electrodes.

15. The sensor of claim 9, wherein each of the groups of interconnected sense electrodes comprises a first sense electrode in one line that at least partially overlaps in the first axis, and is interconnected with, a second sense electrode in another line.

25. The sensor of claim 9, wherein the drive electrodes and sense electrodes are substantially rectangular in shape.

27. The sensor of claim 9, wherein the second axis is the x-axis.

16. A method comprising:

applying drive signals to a plurality of longitudinal drive electrodes in a first layer of a capacitive sensor, the plurality of longitudinal drive electrodes arranged within a first set of regions such that each of the plurality of longitudinal drive electrodes is arranged within only one of the regions in the first set of regions, each region of the first set of regions extending along a first axis of the first layer of the capacitive sensor;

measuring sense signals received from a plurality of longitudinal segmented sense electrodes in the first layer of the capacitive sensor, the plurality of longitudinal segmented sense electrodes arranged within a second set of regions such that each of the plurality of longitudinal segmented sense electrodes is arranged within only one of the regions in the second set of regions, each region of the second set of regions extending along the first axis of the first layer of the capacitive sensor, each region of the second set of regions adjacent to a region of the first set of regions such that no electrodes are present in the first layer between a region of the first set of regions and a region of the second set of regions, each region of the second set of regions distinct from the first set of regions, each region of the second set of regions distinct from one another, the sense signals representing a degree of capacitive coupling of the drive signals between the plurality of longitudinal drive electrodes and the plurality of longitudinal segmented sense electrodes;

determining position in the first axis by an interpolation between sense signals obtained from the plurality of longitudinal segmented sense electrodes; and

determining position in a second axis by an interpolation between sense signals obtained by sequentially driving the plurality of longitudinal drive electrodes with respective drive signals, the second axis different than the first axis.

28. The method of claim 16, wherein the second axis is the x-axis.

17. A capacitive position sensor comprising:

a touch-sensitive area defined by a single-layer of electrodes arranged in a pattern along first and second axes in a first layer, the pattern comprising a plurality of units each occupying a portion of the touch sensitive area along the first axis, and each unit comprising at least three regions extending along the second axis and spaced apart in the first axis such that no electrodes are present in the first layer between any two adjacent regions of the at least three regions and such that no two regions of the at least three regions comprise a common electrode in the first layer, each of the at least three regions distinct from one another, at least one region of the at least three regions comprising a line of sense electrodes situated within the at least one region, each of at least two regions of the at least three regions comprising a line of drive electrodes situated within a single region of the at least three regions, wherein the drive electrodes of each unit are arranged in groups of interconnected drive electrodes, each of the groups of interconnected drive electrodes comprising at least two drive electrodes coupled to one another, the at least two drive electrodes from more than one of the lines of drive electrodes, and each of the groups of interconnected drive electrodes comprising drive electrodes that have at least partially overlapping extents along the second axis.

18. The sensor of claim 17, wherein the drive electrodes have substantially the same extents along the second axis.

19. The sensor of claim 17, wherein at least two of the drive electrodes of one of the plurality of units have varying extents along the second axis.

20. The sensor of claim 17, wherein the at least three regions of each unit are arranged such that:

a first region of the at least three regions comprises a line of sense electrodes;

a second region of the at least three regions comprises a first line of drive electrodes, the second region adjacent to the first region along the first axis;

a third region of the at least three regions comprises a second line of drive electrodes, the third region adjacent to the second region along the first axis; and

a fourth region of the at least three regions comprises a third line of sense electrodes, the fourth region adjacent to the third region along the first axis.

21. The sensor of claim 17, wherein the at least three regions of each unit are arranged such that:

a first region of the at least three regions comprises a first line of drive electrodes;

a second region of the at least three regions comprises a line of sense electrodes, the second region adjacent to the first region along the first axis; and

a third region of the at least three regions comprises a second line of drive electrodes, the third region adjacent to the second region along the first axis.

22. The sensor of claim 17, wherein the drive electrodes and the sense electrodes are substantially rectangular in shape.

29. The sensor of claim 17, wherein the second axis is the x-axis.

23. A method of sensing position of an actuation on a capacitive position sensor having a touch-sensitive area defined by a single-layer of electrodes arranged in a pattern along first and second axes, the pattern comprising a plurality of units each occupying a portion of the touch sensitive area along the first axis, and each unit comprising at least three regions extending parallel to the second axis and spaced apart in the first axis such that no electrodes are present in the first layer between any two adjacent regions of the at least three regions and such that no two regions of the at least three regions comprise a common electrode in the first layer, each of the at least three regions distinct from one another, at least one region of the at least three regions comprising one line of sense electrodes and each of at least two regions of the at least three regions comprising a line of drive electrodes, wherein the drive electrodes of each unit are arranged in groups of interconnected drive electrodes, each of the groups of interconnected drive electrodes having at least two drive electrodes coupled to one another from more than one of the lines of drive electrodes, and the at least two drive electrodes having substantially the same extents along the second axis and being substantially co-terminus, the method comprising:

applying drive signals to the drive electrodes;

measuring sense signals received from each sense electrode representing a degree of capacitive coupling of the drive signals between the drive electrodes and each of the sense electrodes;

determining position in the first axis by an interpolation between sense signals obtained from the sense electrodes of each sense electrode; and

determining position in the second axis by an interpolation between sense signals obtained by sequentially driving the groups of interconnected drive electrodes with respective drive signals.

30. The method of claim 23, wherein the second axis is the x-axis.