Device mountable packaging of ultrasonic transducers

• US 10,445,547 B2
• Filed: 01/25/2017
• Issued: 10/15/2019
• Est. Priority Date: 05/04/2016
• Status: Active Grant

• Current Assignee: Invensense Incorporated (TDK Corporation)
• Original Assignee: Invensense Incorporated (TDK Corporation)
• Inventors: Tsai, Julius Ming-Lin
• Primary Examiner(s): Pihulic, Daniel
• Application Number:
  US15/415,716
• Publication Number:
  US 20170323133A1
• Time in Patent Office: 993 Days
• CPC Class Codes: B06B 1/0292 Electrostatic transducers, e.g. electret-type
• CPC Class Codes: B06B 1/06 operating with piezoelectric effect or with electrostriction piezoelectric or electrostrictive devices per se H10N30/00
• CPC Class Codes: B06B 1/0622 on one surface
• 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: G10K 11/30 using refraction, e.g. acoustic lenses

Abstract

An electronic device including an array of ultrasonic transducers for generating and receiving ultrasonic signals, and an acoustic coupling layer overlying the array of ultrasonic transducers, where the ultrasonic signals are propagated through the acoustic coupling layer.

Claims

1. An electronic device comprising:

an array of ultrasonic transducers for generating and receiving ultrasonic signals;

an acoustic coupling layer overlying the array of ultrasonic transducers, wherein the ultrasonic signals are propagated through the acoustic coupling layer; and

a cover overlying the acoustic coupling layer, wherein the cover has varying thickness.

2. The electronic device of claim 1, wherein the ultrasonic transducers comprise Piezoelectric Micromachined Ultrasonic Transducer (PMUT) devices.

3. The electronic device of claim 1, wherein the ultrasonic transducers comprise Capacitive Micromachined Ultrasonic Transducer (CMUT) devices.

4. The electronic device of claim 1, wherein the cover is curved such that the acoustic coupling layer is thicker at a midpoint of the array of ultrasonic transducers than towards an edge of the array of ultrasonic transducers.

5. The electronic device of claim 1, wherein the cover has varying thickness such that the cover is thinner at a midpoint of the cover and thicker towards an edge of the cover.

6. The electronic device of claim 1 further comprising:

sidewalls bounding the array of ultrasonic transducers and the acoustic coupling layer.

7. The electronic device of claim 1 further comprising:

a plurality of refractive acoustic elements.

8. The electronic device of claim 7, wherein the plurality of refractive acoustic elements are disposed within the acoustic coupling layer such that a refractive acoustic element of the plurality of refractive acoustic elements is associated with an ultrasonic transducer of the array of ultrasonic transducers.

9. The electronic device of claim 8, wherein the plurality of refractive acoustic elements are disposed adjacent to the array of ultrasonic transducers.

10. The electronic device of claim 7 further comprising a cover, wherein the plurality of refractive acoustic elements are disposed within the cover such that a refractive acoustic element of the plurality of refractive acoustic elements is associated with an ultrasonic transducer of the array of ultrasonic transducers.

11. An electronic device comprising:

an array of ultrasonic transducers for generating and receiving ultrasonic signals;

sidewalls bounding the array of ultrasonic transducers;

an acoustic coupling layer overlying the array of ultrasonic transducers and bounded by the sidewalls, wherein the ultrasonic signals are propagated through the acoustic coupling layer, the acoustic coupling layer comprising an acoustic material supporting transmission of the ultrasonic signals; and

a cover overlying the sidewalls and the acoustic coupling layer;

wherein the sidewalls comprise a relief channel for allowing expulsion of excess acoustic material of the acoustic coupling layer from a cavity defined by the array of ultrasonic transducers, the sidewalls and the cover.

12. The electronic device of claim 11, wherein the relief channel is a groove situated at a top edge of the sidewalls.

13. The electronic device of claim 11, wherein the relief channel is an opening situated within the sidewalls.

14. The electronic device of claim 11, wherein the cover comprises a second relief channel for allowing expulsion of excess acoustic material of the acoustic coupling layer from the cavity defined by the array of ultrasonic transducers, the sidewalls and the cover.

15. A mobile device comprising:

a processor;

a memory unit;

a display device disposed on a first surface of the mobile device; and

a fingerprint sensor disposed on a second surface of the mobile device, wherein the second surface is a curved surface having a curvature, such that the fingerprint sensor is curved to match the curvature of the curved surface, the fingerprint sensor comprising;

an array of ultrasonic transducers for generating and receiving ultrasonic signals; and

an acoustic coupling layer overlying the array of ultrasonic transducers, wherein the ultrasonic signals are propagated through the acoustic coupling layer.

16. The mobile device of claim 15, wherein the ultrasonic transducers comprise Piezoelectric Micromachined Ultrasonic Transducer (PMUT) devices.

17. The mobile device of claim 15, wherein the ultrasonic transducers comprise Capacitive Micromachined Ultrasonic Transducer (CMUT) devices.

18. The mobile device of claim 15, wherein the second surface is perpendicular to the first surface.

19. The mobile device of claim 15, wherein the acoustic coupling layer of the fingerprint sensor is curved to match the curvature of the curved surface.

20. The mobile device of claim 15, wherein the fingerprint sensor further comprises a cover overlying the acoustic coupling layer, wherein the cover is curved to match the curvature of the curved surface.

21. The mobile device of claim 20, wherein the cover has varying thickness such that the cover is thinner at a midpoint of the cover and thicker towards an edge of the cover.

22. The mobile device of claim 15, wherein the first surface is a top surface of the mobile device and the second surface is a bottom surface of the mobile device.

23. The mobile device of claim 15, wherein the fingerprint sensor comprises a button overlying the acoustic coupling layer such that the button is disposed on the second surface.