Test techniques for assessing ultrasonic fingerprint sensors

Patent metadata

Field	Value
Publication number	US-9524415-B2
Application number	US-201414553823-A
Country	US
Kind code	B2
Filing date	Nov 25, 2014
Priority date	Jul 18, 2014
Publication date	Dec 20, 2016
Grant date	Dec 20, 2016

Abstract

Techniques for testing ultrasonic fingerprint sensors include operating a fingerprint impress simulator that may cyclically press a contact pad of the simulator against a platen of an ultrasonic sensor under test. A control electronics arrangement may operate the ultrasonic sensor under test and the fingerprint impress simulator, and may receive ultrasonic image data from the ultrasonic sensor under test. The ultrasonic sensor may include an ultrasonic transmitter and an ultrasonic sensor array disposed between the ultrasonic transmitter and the platen. The control electronics arrangement may cause the ultrasonic transmitter to emit an ultrasonic pulse, and may receive ultrasonic image data from the ultrasonic sensor array, the ultrasonic image data being converted from a detected portion of the ultrasonic pulse.

First claim

What is claimed is:

1. An apparatus for testing an ultrasonic sensor under test, the apparatus comprising:
a fingerprint impress simulator including a contact pad; and
a control electronics arrangement configured to operate the ultrasonic sensor under test and the fingerprint impress simulator, and to receive ultrasonic image data from the ultrasonic sensor under test, wherein the contact pad is fabricated from a material having one or more of a stiffness and an acoustic impedance characteristic that simulate skin of a finger and the fingerprint impress simulator is configured to cyclically press the contact pad against a platen of the ultrasonic sensor under test.

2. The apparatus of claim 1 , wherein:
the ultrasonic sensor includes an ultrasonic transmitter and an ultrasonic sensor array disposed between the ultrasonic transmitter and the platen; and
the control electronics arrangement causes the ultrasonic transmitter to emit an ultrasonic pulse, and receives ultrasonic image data from the ultrasonic sensor array, the ultrasonic image data corresponding to a detected portion of the ultrasonic pulse.

3. The apparatus of claim 2 , wherein:
the control electronics arrangement synchronizes a motion of the fingerprint impress simulator and operation of the ultrasonic sensor under test such that the detected portion of the ultrasonic pulse is reflected from the contact pad.

4. The apparatus of claim 1 , wherein:
the fingerprint impress simulator includes (i) a plurality of elongated testing beams; (ii) a plurality of contact pads, each contact pad attached proximate to a distal end of a respective one of the plurality of elongated testing beams; and (iii) a mechanism configured to articulate the plurality of elongated testing beams so as to cyclically engage and disengage each contact with a respective ultrasonic sensor under test.

5. The apparatus of claim 4 , wherein the mechanism includes a rotatable drum arrangement mechanically coupled with the respective elongated testing beams by a linkage arrangement, the linkage arrangement being configured to cause a rotation of the rotatable drum to result in articulation of the plurality of elongated testing beams so as to cyclically engage and disengage each contact pad with a respective ultrasonic sensor under test.

6. The apparatus of claim 5 , wherein the linkage arrangement is configured to cyclically move the distal end of at least one of the plurality of elongated testing beams along a line of motion that is substantially orthogonal to a long axis of the elongated testing beam.

7. The apparatus of claim 6 , wherein the linkage arrangement is configured to provide that a first edge portion of the contact pad makes an initial contact with a surface of the ultrasonic sensor and, only subsequent to the initial contact, a remaining portion of the contact pad is then pressed against the surface.

8. The apparatus of claim 7 , wherein the linkage arrangement is configured to provide that a heel portion of the contact pad may be set to engage the surface prior to a toe portion.

9. The apparatus of claim 4 , wherein the mechanism includes a stepper motor or a plurality of pneumatically or hydraulically driven pistons.

10. The apparatus of claim 5 , wherein the linkage arrangement includes at least one of a cam, a roller, a bearing, a bushing, an integral cam, a protruding section, an offset cylinder and an eccentric.

11. The apparatus of claim 6 wherein the linkage arrangement is configured to move the distal end alternately in opposing directions along the line of motion.

12. The apparatus of claim 1 , wherein the control electronics arrangement is configured to selectably control a pressure with which the fingerprint impress simulator presses the contact pad against the platen.

13. The apparatus of claim 1 , wherein the contact pad is configured with a test pattern having a spatial frequency range simulating a fingerprint.

14. The apparatus of claim 1 , wherein the control electronics arrangement sequences the fingerprint impress simulator through each of a plurality of ultrasonic sensors under test in round-robin fashion.

15. The apparatus of claim 1 , wherein the control electronics arrangement generates a contrast transfer function output.

16. A method comprising:
cyclically pressing a contact pad against a platen of an ultrasonic sensor under test with a fingerprint impress simulator; and
operating, with a control electronics arrangement, the ultrasonic sensor under test and the fingerprint impress simulator, and receiving ultrasonic image data from the ultrasonic sensor under test, wherein the contact pad is fabricated from a material having one or more of a stiffness and an acoustic impedance characteristic that simulate skin of a finger.

17. The method of claim 16 , wherein the ultrasonic sensor includes an ultrasonic transmitter and an ultrasonic sensor array disposed between the ultrasonic transmitter and the platen, the method including causing the ultrasonic transmitter to emit an ultrasonic pulse, and receiving ultrasonic image data from the ultrasonic sensor array, the ultrasonic image data corresponding to a detected portion of the ultrasonic pulse.

18. The method of claim 17 , wherein:
the control electronics arrangement synchronizes a motion of the fingerprint impress simulator and operation of the ultrasonic sensor under test such that the detected portion of the ultrasonic pulse is reflected from the contact pad.

19. The method of claim 16 , wherein:
the fingerprint impress simulator includes (i) a plurality of elongated testing beams; (ii) a plurality of contact pads, each contact pad attached proximate to a distal end of a respective one of the plurality of elongated testing beams; and (iii) a mechanism that articulates the plurality of elongated testing beams so as to cyclically engage and disengage each contact pad with a respective ultrasonic sensor under test.

20. The method of claim 19 , wherein the mechanism includes a rotatable drum arrangement mechanically coupled with the respective elongated beams by a linkage arrangement, the linkage arrangement being configured to cause a rotation of the rotatable drum to result in articulation of the plurality of elongated testing beams so as to cyclically engage and disengage each contact with a respective ultrasonic sensor under test.

21. The method of claim 16 , wherein the control electronics arrangement is configured to selectably control a pressure with which the fingerprint impress simulator engages the contact pads with the respective ultrasonic sensors.

22. The method of claim 16 , further comprising generating a contrast transfer function output.

23. A non-transitory computer readable medium having software stored thereon, the software including instructions for causing an apparatus to:
cyclically press an contact pad against a platen of an ultrasonic sensor under test with a fingerprint impress simulator; and
operate, with a control electronics arrangement, the ultrasonic sensor under test and the fingerprint impress simulator, and receive ultrasonic image data from the ultrasonic sensor under test, wherein the contact pad is fabricated from a material having one or more of a stiffness and an acoustic impedance characteristic that simulate skin of a finger.

24. The computer readable medium of claim 23 , wherein:
the fingerprint impress simulator includes (i) a plurality of elongated testing beams; (ii) a plurali

Assignees

• Qualcomm Inc

Inventors

• Liu Jianwei
• Himaka Norman Satoru
• Antao Sherman Sebastian
• Lawrence Micah Timothy
• Burns David William
• Djordjev Kostadin Dimitrov

Classifications

• H01H11/0062

  Testing or measuring non-electrical properties of switches, e.g. contact velocity (monitoring contacts H01H1/0015; monitoring gas density H01H33/563; monitoring vacuum H01H33/668; calibrating H01H69/01; adjusting H01H71/74; testing of electrical properties G01R31/333) · CPC title

• G06K9/0002 Primary

  Physics · mapped topic

• G01R31/2829 Primary

  Testing of circuits in sensor or actuator systems (testing of apparatus for measuring electric or magnetic variables G01R35/00; testing of indicating or recording apparatus G01D; in airbag systems B60R21/0173; checking gas analysers G01N33/007; monitoring or fail-safe circuits for electromagnets H01F7/1844) · CPC title

• G06V40/1306 Primary

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