Fingerprint sensor pattern

1. A fingerprint sensor array, comprising:

a plurality of first electrodes disposed in a first layer, wherein the plurality of first electrodes is arranged according to a pitch of the first electrodes;

a plurality of second electrodes disposed in a second layer, wherein each second electrode crosses each first electrode to provide a pattern of non-overlapping fingerprint sensor areas wherein each non-overlapping fingerprint sensor area is associated with a different crossing; and

a plurality of propagating electrodes disposed in the second layer, wherein each non-overlapping fingerprint sensor area includes a portion of at least one propagating electrode, and wherein each of the plurality of second electrodes is galvanically isolated from the plurality of first electrodes and the plurality of propagating electrodes.

2. The fingerprint sensor array of claim 1 , wherein one or more of the plurality of propagating electrodes is coupled to a first electrode, of the plurality of first electrodes, through a conductive member.

3. The fingerprint sensor array of claim 1 , wherein one or more of the plurality of propagating electrodes is capacitively coupled to a first electrode, of the plurality of first electrodes, through a dielectric material.

4. The fingerprint sensor array of claim 1 , wherein each non-overlapping fingerprint sensor area includes at least a portion of a first propagating electrode and at least a portion of a second propagation electrode, wherein a portion of each second electrode within each fingerprint sensor area is disposed between at least the portion of the first propagating electrode and at least the portion of the second propagating electrode.

5. The fingerprint sensor array of claim 1 , wherein a width of each first electrode is greater than half the pitch of the first electrodes.

6. The fingerprint sensor array of claim 1 , wherein a width of each propagating electrode is less than half of a pitch of the second electrodes.

7. The fingerprint sensor array of claim 1 , wherein a width of each propagating electrode is the same as a width of at least one of the second plurality of electrodes.

8. The fingerprint sensor array of claim 1 , wherein the second electrode of at least one of the fingerprint sensor areas comprises at least on main trace and a primary trace that branches away from the at least one main trace, wherein the fingerprint sensor area includes at least a portion of the primary trace.

9. The fingerprint sensor of claim 1 , wherein an active area including the pattern of non-overlapping fingerprint sensor areas has an area in the range of 16 mm 2 to 144 mm 2 .

10. The fingerprint sensor of claim 1 , wherein the pattern of non-overlapping fingerprint sensor areas includes at least 1000 discrete fingerprint sensor areas.

11. The fingerprint sensor of claim 1 , wherein a pitch of the first electrodes and is less than 100 um.

12. A method comprising:

driving one or more transmit signals on a plurality of first electrodes disposed in a first layer and a plurality of propagating electrodes disposed in a second layer; and

measuring a capacitance of each of a plurality of fingerprint sensors through a plurality of second electrodes, wherein each second electrode crosses each first electrode to provide a plurality of discrete fingerprint sensors, wherein each discrete fingerprint sensor includes a portion of at least one propagating electrode, and wherein each of the plurality of second electrodes is galvanically isolated from the plurality of first electrodes and the plurality of propagating electrodes.

13. The method of claim 12 , further comprising detecting a fingerprint feature based on the measuring of the capacitance, wherein the detecting the fingerprint feature comprises detecting a change in capacitance that is less than 0.1 fF.

14. The method of claim 12 , wherein the driving of the one or more transmit signals on the plurality of propagating electrodes comprises capacitively coupling to the propagating electrodes.

15. A system comprising:

a fingerprint module comprising transmit electrodes disposed in a first layer, receive electrodes disposed in a second layer, and propagating electrodes disposed in the second layer, wherein each receive electrode crosses each transmit electrode to provide a plurality of discrete fingerprint sensor areas, each discrete fingerprint sensor area associated with a different crossing and comprising a portion of at least one propagating electrode;

an insulating material disposed between the first layer and the second layer;

an overlay material disposed above the second layer; and

a processing device coupled to the fingerprint module to drive the transmit electrodes and provide fingerprint data based on sensor signals received through the receive electrodes, wherein the fingerprint data represents at least one fingerprint feature.

16. The system of claim 14 , wherein an active area including the plurality of discrete fingerprint sensor areas has an area in the range of 16 mm 2 to 144 mm 2 .

17. The system of claim 14 , wherein the plurality of discrete fingerprint sensor areas includes at least 1000 discrete fingerprint sensor areas.

18. The system of claim 15 , wherein the processing device is configured to detect a first fingerprint feature place on the overlay material through at least three discrete fingerprint sensor areas, of the plurality of discrete fingerprint sensor areas.

19. The system of claim 15 , wherein a width of each transmit electrode is wider than half a pitch of the discrete fingerprint sensor areas.

20. The system of claim 15 , wherein a pitch of the transmit electrodes is less than 100 um.