Capacitive Touch Sensor for Identifying a Fingerprint

• US 20140047706A1
• Filed: 10/18/2013
• Published: 02/20/2014
• Est. Priority Date: 11/02/2010
• Status: Active Grant

• Current Assignee: Neodrón Limited (Atlantic IP Services Limited)
• Original Assignee: Jalil Shaikh
• Inventors: Shaikh, Jalil, Yilmaz, Esat
• Granted Patent: US 9,465,491 B2
• Time in Patent Office: Days
• US Class Current: 29/622
• CPC Class Codes: G06F 2203/0338 Fingerprint track pad, i.e. fingerprint sensor used as pointing device tracking the fingertip image
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: G06V 40/1306 non-optical, e.g. ultrasonic or capacitive sensing
• CPC Class Codes: Y10T 29/49105 Switch making
• CPC Class Codes: Y10T 29/49124 On flat or curved insulated base, e.g., printed circuit, etc.

Abstract

A capacitive sensor includes at least one substrate, a capacitive touch position sensor, and a capactive fingerprint sensor. The capacitive touch position sensor is included on the at least one substrate and in a touch sensing area. The capactive touch position sensor includes electrodes configured to enable detection of the presence and position of a touch in the touch sensing area. The capactive fingerprint sensor is included on the at least one substrate and in a fingerprint sensing area. The capacitive fingerprint sensor includes electrodes configured to enable identification of the fingerprint of a finger placed in the fingerprint sensing area.

Claims

1-16. -16. (canceled)

17. A method of forming a capacitive sensor, the method comprising:

forming a plurality of sense electrodes and drive electrodes of a capacitive touch position sensor in a touch sensing area of a capacitive sensor, the plurality of first electrodes configured to enable detection of the presence and position of a touch in the touch sensing area; and

forming a plurality of sense electrodes and drive electrodes of a capacitive fingerprint sensor in a fingerprint sensing area of the capacitive sensor, the plurality of second electrodes configured to enable identification of the fingerprint of a finger placed in the fingerprint sensing area.

18. The method of claim 17, further comprising forming the fingerprint sensing area outside the touch sensing area.

19. The method of claim 17, further comprising forming the fingerprint sensing area within the touch sensing area.

20. The method of claim 19, further comprising coupling the plurality of sense electrodes and drive electrodes of the capacitive fingerprint sensor to a switching element for switching the plurality of sense electrodes and drive electrodes between a fingerprint recognition mode and a touch sensing mode.

21. The method of claim 20, wherein the fingerprint sensor comprises at least two channels, the fingerprint sensor configured to combine the at least two channels while operating in the touch sensing mode.

22. The method of claim 17, wherein:

forming the plurality of sense electrodes and drive electrodes of the capacitive touch position sensor comprises forming the plurality of sense electrodes and drive electrodes on a surface of a substrate; and

forming the plurality of sense electrodes and drive electrodes of the capacitive fingerprint sensor comprises forming the plurality of sense electrodes and drive electrodes on the surface of the substrate.

23. The method of claim 17, wherein a first density of the plurality of sense electrodes and drive electrodes of the capacitive fingerprint sensor is greater than a second density of the plurality of sense electrodes and drive electrodes of the capacitive touch position sensor.

24. The method of claim 17, further comprising forming the plurality of sense electrodes and drive electrodes of the capacitive touch position sensor and the plurality of sense electrodes and drive electrodes of the capacitive finger print sensor from a common conductive material.

25. The method of claim 24, wherein the common conductive material comprises an opaque conductive material.

26. The method of claim 24, wherein the common conductive material comprises a transparent conductive material.

27. A method of forming a capacitive sensor, comprising:

forming a first conductive layer, comprising a plurality of first electrodes of a capacitive touch position sensor in a touch sensing area of the capacitive sensor and a plurality of first electrodes of a capacitive fingerprint sensor in a fingerprint sensing area of a capacitive sensor; and

forming a second conductive layer, comprising a plurality of second electrodes of the capacitive touch position sensor in the touch sensing area of the capacitive sensor and a plurality of second electrodes of the capacitive fingerprint sensor in the fingerprint sensing area of the capacitive sensor;

wherein at least the first and second electrodes of the capacitive fingerprint sensor are formed in such a manner as to provide a density of capacitive sensing channels sufficient for sensing of a fingerprint of a finger touching the fingerprint sensing area.

28. The method of claim 27, further comprising:

forming a substrate from an insulating material;

forming the plurality of first electrodes of the capacitive touch position sensor and the plurality of first electrodes of the capacitive fingerprint sensor on a first surface of the substrate; and

forming the plurality of second electrodes of the capacitive touch position sensor and the plurality of second electrodes of the capacitive fingerprint sensor on a second surface of the substrate, and

wherein the second surface is different from the first surface so that the substrate provides electrical isolation between electrodes formed by the first conductive layer and electrodes formed by the second conductive layer.

29. The method of claim 27, further comprising:

forming the plurality of first electrodes of the capacitive touch position sensor and the plurality of first electrodes of the capacitive fingerprint sensor on a surface of a first substrate; and

forming the plurality of second electrodes of the capacitive touch position sensor and the plurality of second electrodes of the capacitive fingerprint sensor on a surface of a second substrate that is different from the first substrate.

30. The method of claim 27, further comprising forming the fingerprint sensing area outside the touch sensing area.

31. The method of claim 27, further comprising forming the fingerprint sensing area within the touch sensing area.

32. The method of claim 31, further comprising:

coupling the plurality of first electrodes of the capacitive fingerprint sensor and the plurality of second electrodes of the capacitive fingerprint sensor to a switching element for switching between a fingerprint recognition mode and a touch sensing mode.

33. The method of claim 27, wherein a first density of the plurality of first electrodes and second electrodes of the capacitive fingerprint sensor is greater than a second density of the plurality of first electrodes and second electrodes of the capacitive touch position sensor.

34. The method of claim 27, further comprising forming the plurality of first and second electrodes of the capacitive touch position sensor and the plurality of first and second electrodes of the capacitive fingerprint sensor from a common conductive material.

35. The method of claim 34, wherein the common conductive material comprises an opaque conductive material.

36. The method of claim 34, wherein the common conductive material comprises a transparent conductive material.