Fingerprint sensing device

Patent metadata

Field	Value
Publication number	US-10846503-B2
Application number	US-201916297640-A
Country	US
Kind code	B2
Filing date	Mar 9, 2019
Priority date	Mar 19, 2018
Publication date	Nov 24, 2020
Grant date	Nov 24, 2020

Abstract

In accordance with a first aspect of the present disclosure, a fingerprint sensing device is provided, comprising: a substrate; a fingerprint sensor placed on one side of the substrate; a coupling electrode placed on another side of the substrate, wherein said coupling electrode is arranged to provide a coupling capacitance between a surface of a finger and a circuit ground of said fingerprint sensor. In accordance with a second aspect of the present disclosure, a corresponding method of producing a fingerprint sensing device is conceived.

First claim

The invention claimed is:

1. A fingerprint sensing device comprising:
a substrate;
a fingerprint sensor placed on one side of the substrate;
a coupling electrode placed on another side of the substrate, wherein said coupling electrode is arranged to provide a coupling capacitance between a surface of a finger and a circuit ground of said fingerprint sensor, wherein the fingerprint sensing device is fixed to an index tape for facilitating embedding the fingerprint sensing device in a smartcard, wherein the index tape has a plurality of regularly spaced index holes in a longitudinal tape direction in a line on both edges of the index tape, and wherein a first dimension of the device is a multiple of a distance between each hole of the plurality of regularly spaced index holes.

2. The device of claim 1 , wherein the coupling electrode is further arranged to provide an electrostatic discharge path.

3. The device of claim 1 , wherein the coupling electrode, when projected in a vertical direction on a horizontal plane in which the fingerprint sensor is placed, does not overlap with said fingerprint sensor.

4. The device of claim 1 , wherein the coupling electrode, when projected in a vertical direction on a horizontal plane in which the fingerprint sensor is placed, surrounds said fingerprint sensor.

5. The device of claim 1 , wherein the coupling electrode comprises at least one gap.

6. The device of claim 1 , wherein the fingerprint sensor comprises a plurality of sensor elements formed by capacitive sense plates.

7. The device of claim 1 , further comprising an electrostatic discharge grid, wherein the coupling electrode is electrically coupled to said electrostatic discharge grid.

8. The device of claim 1 , wherein the coupling electrode is connected by a via and a conductive connection to said circuit ground.

9. The device of claim 1 , further comprising a coating on said other side of the substrate, wherein the coating has a thickness in the range of 5 μm to 50 μm.

10. The device of claim 1 , wherein the coupling electrode is larger in area than the fingerprint sensor by a factor in the range of 1.5 to 4.

11. The device of claim 1 , being embedded in a T-shaped package.

12. A smart card, a wearable device, an Internet of Things device, or a smart grid device comprising the fingerprint sensing device of claim 1 .

13. The device of claim 1 , wherein a second dimension of the device permits two devices to fit on a width of the index tape.

14. A method of producing a fingerprint sensing device:
placing a fingerprint sensor on one side of a substrate;
placing a coupling electrode on another side of the substrate, wherein said coupling electrode is arranged to provide a coupling capacitance between a surface of a finger and a circuit ground of said fingerprint sensor, wherein the fingerprint sensing device is fixed to an index tape for facilitating embedding the fingerprint sensing device in a smartcard, wherein the index tape has a plurality of regularly spaced index holes in a longitudinal tape direction in a line on both edges of the index tape, and wherein a first dimension of the device is a multiple of a distance between each hole of the plurality of regularly spaced index holes.

15. The method of claim 14 , wherein the coupling electrode is placed such that, when the coupling electrode is projected in a vertical direction on a horizontal plane in which the fingerprint sensor is placed, the coupling electrode does not overlap with said fingerprint sensor.

16. The method of claim 15 , wherein the coupling electrode is placed such that, when the coupling electrode is projected in a vertical direction on a horizontal plane in which the fingerprint sensor is placed, the coupling electrode surrounds said fingerprint sensor.

17. The method of claim 14 , wherein a second dimension of the device permits two devices to fit on a width of the index tape.

Assignees

• Nxp Bv

Inventors

• Suwald Thomas

Classifications

• G06V40/1306 Primary

  non-optical, e.g. ultrasonic or capacitive sensing · CPC title

• G06V40/1329 Primary

  Protecting the fingerprint sensor against damage caused by the finger · CPC title

• G06K19/0718

  the sensor being of the biometric kind, e.g. fingerprint sensors (fingerprint sensors in general G06V40/13; biometric access-control systems in general, see G07C9/00) · CPC title

• G06K9/0002 Primary

  Physics · mapped topic

• G06K9/00053

  Physics · mapped topic