Integrated finger print sensor
A fingerprint sensor and fingerprint sensor system especially for integration in a device having an overlay made of an insulating material comprises a plurality of sensing elements positioned on a first side of the overlay; a plurality of probes positioned in a predetermined pattern defining a fingerprint sensing area on a second side of the overlay, the plurality of probes extending from the first side of the overlay at least partially through the overlay; a plurality of conductor leads on the first side of the overlay interconnecting the plurality of probes with the plurality of sensing elements; a plurality of amplifiers connected to the plurality of sensing elements, the number of amplifiers being less than the number of sensing elements; and an activation circuit connected to the plurality of sensing elements, the activation circuit being adapted to output at least one activation signal.
1. A fingerprint sensor configured for integration in a device having an overlay made of an insulating material, the fingerprint sensor comprising:
a plurality of sensing elements positioned on a first side of the overlay, wherein the plurality of sensing elements comprises:
a sensing electrode defined in a first conductive layer;
a first dielectric layer under the sensing electrode; and
an activation electrode and a pick-up electrode defined in a second conductive layer on the opposite side of the first dielectric layer from the sensing electrode, wherein the activation electrode and the pick-up electrode are at least partially covered by the sensing electrode;
a plurality of probes defining a fingerprint sensing area on a second side of the overlay, the plurality of probes extending from the first side of the overlay at least partially through the overlay; and
a plurality of conductor leads on the first side of the overlay interconnecting the plurality of probes with the plurality of sensing elements.
2. The fingerprint sensor according to claim 1 , wherein all of the plurality of probes extend partially through the overlay.
3. The fingerprint sensor according to claim 1 , wherein each probe of a first number of the plurality of probes extends partially through the overlay; and
each probe of a second number of the plurality of probes extends through the overlay.
4. The fingerprint sensor according to claim 1 , wherein each probe of a number of the plurality of probes extends through the overlay; and
at least one of the portion of probes extending through the overlay is covered with a dielectric layer.
5. The fingerprint sensor according to claim 1 , wherein the insulating material is selected from a group consisting of glass, Poly methyl methacrylate and polycarbonate.
6. The fingerprint sensor according to claim 1 , wherein each sensing element is configured to be activated by an activation signal comprising an alternating current or voltage signal, and output a response signal modulated by the activation signal when activated.
7. The fingerprint sensor according to claim 6 , wherein the sensing elements are grouped in sets of sensing elements, and each sensing element in a set of sensing elements is adapted to be simultaneously activated by an activation signal common to all of the sensing elements in the set of sensing elements.
8. The fingerprint sensor according to claim 1 , wherein the first conductive layer is defined in a conductor lead layer on a first side of the overlay.
9. The fingerprint sensor according to claim 8 , wherein the plurality of sensing elements is positioned on a substrate that is separate from the overlay and is electrically connected to the conductor lead layer on the first side of the overlay.
10. The fingerprint sensor according to claim 9 , wherein the separate substrate is a multi-layer polymer substrate.
11. The fingerprint sensor according to claim 1 , wherein the plurality of sensing elements further comprises:
a second dielectric layer under the second conductive layer; and
an activation line defined in a third conductive layer on an opposite side of the second dielectric layer from the second conductive layer, wherein the activation line is electrically connected to the activation electrode.
12. The fingerprint sensor according to claim 11 , wherein the activation line is electrically connected to the activation electrode through a conductive via.
13. The fingerprint sensor according to claim 11 , wherein the activation line is electrically connected to the activation electrode by way of capacitive coupling over the second dielectric layer.
14. The fingerprint sensor according to claim 1 , wherein the probes are positioned in a transparent section of the overlay, the conductor leads are routed to a processing unit outside the transparent area, and the probes and the conductor leads are made of an essentially transparent material.
15. A fingerprint sensor system configured for integration in a device having an overlay made of an insulating material, the fingerprint sensor system comprising:
a plurality of sensing elements positioned on a first side of the overlay;
a plurality of probes defining a fingerprint sensing area on a second side of the overlay, the plurality of probes extending from the first side of the overlay at least partially through the overlay;
a plurality of conductor leads on the first side of the overlay interconnecting the plurality of probes with the plurality of sensing elements;
a plurality of amplifiers connected to the plurality of sensing elements, the number of amplifiers being less than the number of sensing elements; and
an activation circuit connected to the plurality of sensing elements, the activation circuit being adapted to output at least one activation signal, wherein the plurality of sensing elements further comprises:
a sensing electrode defined in a first conductive layer;
a first dielectric layer under the sensing electrode;
an activation electrode and a pick-up electrode defined in a second conductive layer on an opposite side of the first dielectric layer from the first conductive layer, wherein the activation electrode and the pick-up electrode are at least partially covered by the sensing electrode;
wherein the activation electrode is connected to the activation circuit; and
wherein the pick-up electrode is connected to one of the plurality of amplifiers.
16. The fingerprint sensor system according to claim 15 , wherein each sensing element is adapted to be activated by an activation signal comprising an alternating current or voltage signal from the activation circuit, and when activated, output a response signal modulated by the activation signal to one of the plurality of amplifiers.
17. The fingerprint sensor system according to claim 16 , wherein the sensing elements are grouped in sets of sensing elements, and each sensing element in a set of sensing elements is adapted to be simultaneously activated by an activation signal from the activation circuit common to all of the sensing elements in the set of sensing elements.
18. The fingerprint sensor system according to claim 17 , wherein the activation circuit is further adapted to
to sequentially switch the activation signal to activate one of the set of sensing elements at one time.
19. The fingerprint sensor system according to claim 15 , wherein the plurality of sensing elements further comprise:
a second dielectric layer under the second conductive layer; and
an activation line defined in a third conductive layer on an opposite side of the second dielectric layer from the second conductive layer, wherein the activation line is electrically connected to the activation electrode such that the activation electrode is connected to the activation circuit through the activation line.
20. The fingerprint sensor system according to claim 15 , wherein
the plurality of probes is arranged in a one or two-dimensional pattern, the two-dimensional pattern corresponding to m rows of sensing elements and n columns of sensing elements, where m≧1 and n>1;
the pick-up electrode of each sensing element in a column is connected to one of n amplifiers through a common pick-up line;
the activation electrode of each sensing element in a row is connected to an activation signal through a common activation line; and
the activation circuit is configured to sequentially switch the activation signal to activate each of the sensing elements in a row such that a resulting signal is sensed on the respective pick-up electrode and amplified by the respective column amplifier.
21. The fingerprint sensor system according to claim 17 , wherein the sets of sensing elements are arranged in an essentially linear array, each set of sensing elements essentially defining a swipe fingerprint sensor.
22. The fingerprint sensor system according to claim 21 , wherein the activation circuit is further adapted to receive input from the touch-enabled display; and the activation circuit activates one of the sets of sensing elements based on the input from the touch-enabled display.
23. The fingerprint sensor system according to claim 22 , wherein the input from the touch-enabled display includes the speed and direction of a finger moving over the touch-enabled display.
24. The finger print sensor of claim 1 , wherein the plurality of sensing elements comprises:
two or more drive lines disposed in a side-by-side arrangement, and
two or more pickup elements disposed in a side-by-side arrangement and oriented transversely to said drive lines.
25. The finger print sensor system of claim 15 , wherein the plurality of sensing elements comprises:
two or more drive lines disposed in a side-by-side arrangement, and
two or more pickup elements disposed in a side-by-side arrangement and oriented transversely to said drive lines.