Fingerprint sensing assemblies and methods of making

• US 7,751,601 B2
• Filed: 10/04/2005
• Issued: 07/06/2010
• Est. Priority Date: 10/04/2004
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Validity Sensors Incorporated (Synaptics Incorporated)
• Inventors: Benkley, Fred G. III
• Primary Examiner(s): Mehta; Bhavesh M
• Assistant Examiner(s): Thomas; Mia M
• Application Number:
  US11/243,100
• Publication Number:
  US 20060083411A1
• Time in Patent Office: 1,736 Days
• Field of Search: 382115-127, 382/106, 382/107, 382/181, 382/312, 340 51- 592, 356 27- 285, 326/41
• US Class Current: 382/124
• CPC Class Codes: G06V 40/1306 non-optical, e.g. ultrasonic or capacitive sensing
• CPC Class Codes: G06V 40/1329 Protecting the fingerprint sensor against damage caused by the finger
• CPC Class Codes: G06V 40/1359 Extracting features related to ridge properties; Determining the fingerprint type, e.g. whorl or loop
• CPC Class Codes: G06V 40/1376 Matching features related to ridge properties or fingerprint texture
• CPC Class Codes: Y10T 29/4913 Assembling to base an electrical component, e.g., capacitor, etc.

Abstract

A fingerprint sensing module includes a sensor substrate having a sensing side and a circuit side, an image sensor including conductive traces on the circuit side of the sensor substrate, and a sensor circuit including at least one integrated circuit mounted on the circuit side of the sensor substrate and electrically connected to the image sensor. The sensor substrate may be a flexible substrate. The module may include a velocity sensor on the sensor substrate or on a separate substrate. The module may further include a rigid substrate, and the sensor substrate may be affixed to the rigid substrate.

Claims

1. A fingerprint sensing module comprising:

a sensor substrate having a sensing side and a circuit side;

an image sensor including conductive traces on the circuit side of the sensor substrate and comprising;

at least one linear array of capacitive sensors for capacitive sensing of ridge peaks and ridge valleys of a fingerprint on a moving finger,

at least one image pickup plate disposed generally orthogonally to a direction of movement of the finger, and at least one drive plate in spaced relation to said at least one image pickup plate to define at least one sensor gap between the respective at least one image drive plate and said at least one image pickup plate, wherein the ridge peaks and ridge valleys of the fingerprint passing over the at least one sensor gap produce a change in capacitance between the respective at least one image drive plate and said at least one image pickup plate; and

a sensor circuit including at least one integrated circuit mounted on the circuit side of the sensor substrate and electrically connected to the image sensor.

2. A fingerprint sensing module as defined in claim 1, further comprising a velocity sensor including conductive traces on the circuit side of the sensor substrate, wherein the velocity sensor is electrically connected to the sensor circuit.

3. A fingerprint sensing module as defined in claim 2, wherein the sensor substrate comprises a flexible film.

4. A fingerprint sensing module as defined in claim 3, further comprising a rigid substrate, wherein the circuit side of the sensor substrate is affixed to a first surface of the rigid substrate.

5. A fingerprint sensing module as defined in claim 4, wherein the circuit side of the sensor substrate is affixed to the first surface of the rigid substrate with an adhesive.

6. A fingerprint sensing module as defined in claim 4, wherein a first section of the sensor substrate is affixed to the first surface of the rigid substrate with an adhesive and a second section of the sensor substrate is attachable to another device.

7. A fingerprint sensing module as defined in claim 4, wherein the rigid substrate includes a cutout for receiving the at least one integrated circuit.

8. A fingerprint sensing module as defined in claim 4, further comprising one or more circuit components mounted on a second surface of the rigid substrate, wherein the one or more circuit components are connected to the sensor circuit.

9. A fingerprint sensing module as defined in claim 8, wherein the one or more circuit components include an electrical connector.

10. A fingerprint sensing module as defined in claim 8, wherein the one or more circuit components are connected to the sensor circuit by vias through the rigid substrate.

11. A fingerprint sensing module as defined in claim 4, wherein the sensor substrate and the rigid substrate are electrically connected by conductive adhesive between conductive interconnect pads on the respective substrates.

12. A fingerprint sensing module as defined in claim 4, wherein the sensor substrate has a larger area than the rigid substrate.

13. A fingerprint sensing module as defined in claim 4, wherein the sensor substrate is affixed to at least two surfaces of the rigid substrate.

14. A fingerprint sensing module as defined in claim 4, further comprising a base for mounting of the sensor substrate and the rigid substrate.

15. A fingerprint sensing module as defined in claim 14, wherein the base has a curved surface for mounting of the sensor substrate.

16. A fingerprint sensing module as defined in claim 3, wherein the at least one integrated circuit is affixed to the sensor substrate by a chip-on-film process.

17. A fingerprint sensing module as defined in claim 2, wherein said velocity sensor comprises two or more finger detectors spaced apart along a direction of movement of the finger, each of said finger detectors including at least one drive plate and at least one pickup plate, wherein an end of the finger passing over each of said finger detectors produces a change in capacitance between respective drive plates and pickup plates.

18. A fingerprint sensing module as defined in claim 2, wherein the sensor substrate comprises a rigid substrate.

19. A fingerprint sensing module as defined in claim 1, wherein the image sensor comprises an image pickup plate disposed generally orthogonally to a direction of movement of the finger, and a plurality of image drive plates in spaced relation to said image pickup plate to define a plurality of sensor gaps between respective image drive plates and said image pickup plate, wherein the ridge peaks and ridge valleys of the fingerprint passing over the sensor gaps produce a change in capacitance between respective image drive plates and said image pickup plate.

20. A fingerprint sensing module as defined in claim 19, wherein said image pickup plate and said plurality of image drive plates are substantially coplanar.

21. A fingerprint sensing module as defined in claim 1, wherein the sensor substrate is configured so that a finger is swiped over the sensing side of the sensor substrate for fingerprint sensing.

22. A fingerprint sensing module as defined in claim 1, further comprising a flexible substrate having a velocity sensor including conductive traces on the flexible substrate, wherein the velocity sensor is electrically connected to the sensor circuit, and a base for mounting the sensor substrate and the flexible substrate such that the image sensor and the velocity sensor are substantially coplanar.

23. A fingerprint sensing module comprising:

a flexible substrate having a sensing side and a circuit side;

an image sensor including conductive traces on the circuit side of the flexible substrate and comprising;

at least one linear array of capacitive sensors for capacitive sensing of ridge peaks and ridge valleys of a fingerprint on a moving finger,

at least one image pickup plate disposed generally orthogonally to a direction of movement of the finger, and at least one drive plate in spaced relation to said at least one image pickup plate to define at least one sensor gap between the respective at least one image drive plate and said at least one image pickup plate, wherein the ridge peaks and ridge valleys of the fingerprint passing over the at least one sensor gap produce a change in capacitance between the respective at least one image drive plate and said at least one image pickup plate; and

a velocity sensor including conductive traces on the circuit side of the flexible substrate;

a sensor circuit including at least one integrated circuit mounted on the circuit side of the flexible substrate and electrically connected to the image sensor and the velocity sensor; and

a rigid substrate, wherein the circuit side of the flexible substrate is affixed to a surface of the rigid substrate.

24. A fingerprint sensing module comprising:

a rigid substrate;

an image sensor including conductive traces on the substrate and comprising;

at least one linear array of capacitive sensors for capacitive sensing of ridge peaks and ridge valleys of a fingerprint on a moving finger,

at least one image pickup plate disposed generally orthogonally to a direction of movement of the finger, and at least one drive plate in spaced relation to said at least one image pickup plate to define at least one sensor gap between the respective at least one image drive plate and said at least one image pickup plate, wherein the ridge peaks and ridge valleys of the fingerprint passing over the at least one sensor gap produce a change in capacitance between the respective at least one image drive plate and said at least one image pickup plate; and

a velocity sensor including conductive traces on the substrate; and

a sensor circuit including at least one integrated circuit mounted on the substrate and electrically connected to the image sensor and the velocity sensor, wherein the image sensor, the velocity sensor and the sensor circuit are mounted on a first surface of the rigid substrate.

25. A fingerprint sensing module as defined in claim 24, further comprising a protective coating over the image sensor and the velocity sensor.

26. A fingerprint sensing module as defined in claim 24, wherein the image sensor comprises a linear array of capacitive sensors for capacitive sensing of ridge peaks and ridge valleys of a fingerprint on a moving finger.

27. A fingerprint sensing module as defined in claim 26, wherein the image sensor comprises an image pickup plate disposed generally orthogonally to a direction of movement of the finger, and a plurality of image drive plates in spaced relation to said image pickup plate to define a plurality of sensor gaps between respective image drive plates and said image pickup plate, wherein the ridge peaks and ridge valleys of the fingerprint passing over the sensor gaps produce a change in capacitance between respective image drive plates and said image pickup plate.

28. A fingerprint sensing module as defined in claim 27, wherein the velocity sensor comprises two or more finger detectors spaced apart along a direction of movement of the finger, each of said finger detectors including at least one drive plate and at least one pickup plate, wherein an end of the finger passing over each of said finger detectors produces a change in capacitance between respective drive plates and pickup plates.

29. A method for making a fingerprint sensing module, comprising:

providing a flexible substrate having a sensing side and a circuit side;

forming an image sensor including conductive traces on the circuit side of the flexible substrate and comprising;

at least one linear array of capacitive sensors for capacitive sensing of ridge peaks and ridge valleys of a fingerprint on a moving finger,

at least one image pickup plate disposed generally orthogonally to a direction of movement of the finger, and at least one drive plate in spaced relation to said at least one image pickup plate to define at least one sensor gap between the respective at least one image drive plate and said at least one image pickup plate, wherein the ridge peaks and ridge valleys of the fingerprint passing over the at least one sensor gap produce a change in capacitance between the respective at least one image drive plate and said at least one image pickup plate; and

forming a velocity sensor including conductive traces on the circuit side of the flexible substrate;

mounting a sensor circuit including at least one integrated circuit on the circuit side of the flexible substrate; and

affixing the circuit side of the flexible substrate to a surface of a rigid substrate.

30. A fingerprint sensing module comprising:

a first flexible substrate having an image sensor including conductive traces on the first flexible substrate, said image sensor comprising;

at least one linear array of capacitive sensors for capacitive sensing of ridge peaks and ridge valleys of a fingerprint on a moving finger,

at least one image pickup plate disposed generally orthogonally to a direction of movement of the finger, and at least one drive plate in spaced relation to said at least one image pickup plate to define at least one sensor gap between the respective at least one image drive plate and said at least one image pickup plate, wherein the ridge peaks and ridge valleys of the fingerprint passing over the at least one sensor gap produce a change in capacitance between the respective at least one image drive plate and said at least one image pickup plate; and

said first flexible substrate also having a sensor integrated circuit mounted on the first flexible substrate and electrically connected to the image sensor;

said conductive traces operating as a velocity sensor; and

a base for mounting the first flexible substrates so that the conductive traces of the image sensor and the velocity sensor are substantially unitary.

31. A fingerprint sensing module as defined in claim 30, further comprising a rigid substrate mounted to the base and connected to the first flexible substrate.