Touch sensor having a single sensor layer
In one aspect, a touch sensor includes a dielectric surface layer; drive electrodes disposed on the dielectric surface layer and arranged radially about a center, the drive electrodes defining a perimeter about the center, and a sense electrode disposed on the dielectric surface layer and arranged between two of the drive electrodes. Each drive electrode can include: an outer radial section extending radially along the perimeter; a central section extending from the outer radial section towards the center; and an inner radial section comprising a first section extending radially away from the central section in a first radial direction and a second section, shorter than the first section, extending radially away from the central section in a second radial direction.
1. A touch sensor comprising:
a dielectric surface layer;
a plurality of drive electrodes disposed on the dielectric surface layer and arranged radially about a center, the drive electrodes defining a perimeter about the center, wherein each drive electrode comprises:
an outer radial section extending radially along the perimeter;
a central section extending from the outer radial section towards the center; and
an inner radial section comprising a first section extending radially away from the central section in a first radial direction and a second section, shorter than the first section, extending radially away from the central section in a second radial direction; and
a sense electrode disposed on the dielectric surface layer and arranged between two of the drive electrodes, wherein a distance between the sense electrode and the outer radial section of each of the two of the drive electrodes is associated with a thickness of each section of the drive electrode.
2. The touch sensor of claim 1 , wherein the sense electrode comprises:
a first central section extending, between first and second drive electrodes, from the perimeter towards the center;
a first radial section extending radially from an inner end of the first central section towards the first and second drive electrodes; and
a second central section extending, between a first long section of a first inner radial section of the first drive electrode and a first short section of a second inner radial section of the second drive electrode, from the first radial section towards the center.
3. The touch sensor of claim 2 , wherein each section of the drive electrodes has a thickness T, and wherein a distance between the first radial section of each sense electrode and the outer radial section of each drive electrode is T/2.
4. The touch sensor of claim 1 , wherein each section of the drive electrodes has a thickness T, and wherein a distance between a first long section of a first drive electrode and a first short section of a second drive electrode is T/2.
5. The touch sensor of claim 1 , wherein each section of the drive electrodes has a thickness T, and wherein a gap between a first outer radial section of a first drive electrode and a first central section of an adjacent sense electrode spans a distance of T/2.
6. The touch sensor of claim 1 , wherein the drive electrodes and the sense electrode are arranged on a single layer.
7. The touch sensor of claim 1 , comprising a plurality of sense electrodes, wherein each sense electrode is electrically connected to a common sense electrode.
8. The touch sensor of claim 1 , comprising a touch sensor controller configured to pulse each of the drive electrodes at different times and to measure a response from each of the sense electrodes.
9. A touch sensor comprising:
a dielectric surface layer;
a plurality of drive electrodes disposed on the dielectric surface layer and collectively arranged in a rectangular pattern, wherein each drive electrode comprises:
a first horizontal section extending along a horizontal direction;
a vertical section extending along a vertical direction; and
a second horizontal section extending along the horizontal direction from the vertical section towards an adjacent drive electrode; and
a third horizontal section, shorter than the second horizontal section, extending along the horizontal direction from the vertical section towards the adjacent drive electrode; and
a sense electrode disposed on the dielectric surface layer and arranged between two of the drive electrodes, wherein a distance between the sense electrode and the first horizontal section of each of the two of the drive electrodes is associated with a thickness of each section of the drive electrode.
10. The touch sensor of claim 9 , wherein the sense electrode comprises:
a first vertical section extending along the vertical direction between first and second drive electrodes;
a first horizontal section extending along the horizontal direction from a bottom of the first vertical section; and
a second vertical section extending along the vertical direction from the first horizontal section and between the first and second drive electrodes; and
a second horizontal section extending along the horizontal direction from a bottom of the second vertical section.
11. The touch sensor of claim 10 , wherein each section of the drive electrodes has a thickness T, and wherein a distance between the first vertical section of each sense electrode and the top horizontal section of the drive electrode is T/2.
12. The touch sensor of claim 1 , wherein each section of the drive electrodes has a thickness T, and wherein a distance between a first long section of a first drive electrode and a first short section of a second drive electrode is T/2.
13. The touch sensor of claim 1 , wherein each section of the drive electrodes has a thickness T, and wherein a gap between a top horizontal section of a first drive electrode and a first vertical section of a first adjacent sense electrode spans a distance of T/2.
14. The touch sensor of claim 1 , wherein the drive electrodes and the sense electrode are arranged on a single layer.
15. The touch sensor of claim 1 , comprising a plurality of sense electrodes, wherein each sense electrode is electrically connected to a common sense electrode.
16. The touch sensor of claim 1 , comprising a touch sensor controller configured to pulse each of the drive electrodes at different times and to measure a response from each of the sense electrodes.
17. A method performed by a touch sensor controller, the method comprising:
sequentially applying multiple pulses to each drive electrode of a plurality of drive electrodes arranged radially about a center of a touch sensor, the drive electrodes defining a perimeter about the center, wherein each drive electrode comprises:
an outer radial section extending radially along the perimeter;
a central section extending from the outer radial section towards the center; and
an inner radial section comprising a long section extending radially away from the central section in a first direction and a short section, shorter than the long section, extending radially away from the central section in a second direction;
for each drive electrode, measuring a response from a plurality of sense electrodes to the pulse applied to the drive electrode; and
determining a location on a surface of the touch sensor based on the measured responses,
wherein one of the plurality of sense electrodes is arranged between two of the drive electrodes, and a distance between the sense electrode and the outer radial section of each of the two of the drive electrodes is associated with a thickness of each section of the drive electrode.
18. The method of claim 17 , wherein the sense electrodes are arranged in an alternating fashion between the drive electrodes.
19. The method of claim 18 , wherein each sense electrode comprises:
a first central section extending, between first and second drive electrodes, from the perimeter towards the center;
a first radial section extending radially from an inner end of the first central section towards the first and second drive electrodes; and
a second central section extending, between a first long section of a first inner radial section of the first drive electrode and a first short section of a second inner radial section of the second drive electrode, from the first radial section towards the center.
20. The method of claim 17 , wherein the drive electrodes and the sense electrodes are arranged on a single layer, and wherein each sense electrode is connected to a common sense electrode.