Apparatus with ultrasonic fingerprint sensor and one or more resonators, and related systems and methods

Patent metadata

Field	Value
Publication number	US-11798308-B2
Application number	US-202117448037-A
Country	US
Kind code	B2
Filing date	Sep 17, 2021
Priority date	Sep 17, 2021
Publication date	Oct 24, 2023
Grant date	Oct 24, 2023

Abstract

Some disclosed implementations include an ultrasonic sensor stack and an acoustic resonator. The acoustic resonator may be configured to enhance ultrasonic waves transmitted by the ultrasonic sensor stack in an ultrasonic frequency range that is suitable for ultrasonic fingerprint sensors. In some examples, the acoustic resonator may include one or more low-impedance layers residing between a first higher-impedance layer and a second higher-impedance layer. Each of the one or more low-impedance layers may have a lower acoustic impedance than an acoustic impedance of the first higher-impedance layer or an acoustic impedance of the second higher-impedance layer. At least one low-impedance layer may have a thickness corresponding to a multiple of a half wavelength at a peak frequency of the acoustic resonator. The peak frequency may be within a frequency range from 1 MHz. to 20 MHz.

First claim

The invention claimed is:

1. An apparatus, comprising:
an ultrasonic sensor stack; and
an acoustic resonator, comprising:
one or more higher-impedance layers having a thickness corresponding to a multiple of a half wavelength at a peak frequency of the acoustic resonator;
one or more first low-impedance layers residing between a first side of the one or more higher-impedance layers and the ultrasonic sensor stack, each layer of the one or more first low-impedance layers having a lower acoustic impedance than an acoustic impedance of the one or more higher-impedance layers, each layer of the one or more first low-impedance layers having a thickness corresponding to a multiple of a quarter wavelength at the peak frequency of the acoustic resonator; and
one or more second low-impedance layers residing proximate a second side of the one or more higher-impedance layers, each layer of the one or more second low-impedance layers having a lower acoustic impedance than the acoustic impedance of one or more higher-impedance layers, each layer of the one or more second low-impedance layers having a thickness corresponding to the multiple of the quarter wavelength at the peak frequency of the acoustic resonator.

2. The apparatus of claim 1 , wherein one or more of the one or more higher-impedance layers comprise glass.

3. The apparatus of claim 1 , wherein one or more of the one or more higher-impedance layers comprise metal.

4. The apparatus of claim 1 , wherein at least one of the one or more first low-impedance layers or the one or more second low-impedance layers comprises a plurality of layers and wherein the plurality of layers includes at least a first layer and a second layer, the first layer having a first acoustic impedance that is higher than a second acoustic impedance of the second layer.

5. The apparatus of claim 1 , further comprising a display stack.

6. The apparatus of claim 5 , wherein the one or more second low-impedance layers resides between the display stack and the one or more higher-impedance layers.

7. The apparatus of claim 1 , wherein the apparatus is a mobile device that includes the ultrasonic sensor stack and the acoustic resonator.

8. An apparatus, comprising:
ultrasonic sensor means; and
an acoustic resonator, comprising:
one or more higher-impedance layers having a thickness corresponding to a multiple of a half wavelength at a peak frequency of the acoustic resonator;
one or more first low-impedance layers residing between a first side of the one or more higher-impedance layers and the ultrasonic sensor means, each layer of the one or more first low-impedance layers having a lower acoustic impedance than an acoustic impedance of the one or more higher-impedance layers, each layer of the one or more first low-impedance layers having a thickness corresponding to a multiple of a quarter wavelength at the peak frequency of the acoustic resonator; and
one or more second low-impedance layers residing proximate a second side of the one or more higher-impedance layers, each layer of the one or more second low-impedance layers having a lower acoustic impedance than the acoustic impedance of the one or more higher-impedance layers, each layer of the one or more second low-impedance layers having a thickness corresponding to the multiple of the quarter wavelength at the peak frequency of the acoustic resonator.

9. The apparatus of claim 8 , wherein one or more of the one or more higher-impedance layers comprise glass.

10. The apparatus of claim 8 , wherein one or more of the one or more higher-impedance layers comprise metal.

11. The apparatus of claim 8 , wherein at least one of the one or more first low-impedance layers or the one or more second low-impedance layers comprises a plurality of layers and wherein the plurality of layers includes at least a first layer and a second layer, the first layer having a first acoustic impedance that is higher than a second acoustic impedance of the second layer.

12. The apparatus of claim 8 , further comprising a display stack.

13. The apparatus of claim 12 , wherein the one or more second low-impedance layers resides between the display stack and the one or more higher-impedance layers.

14. The apparatus of claim 8 , wherein the apparatus is a mobile device that includes the ultrasonic sensor means and the acoustic resonator.

15. A method, comprising:
controlling, via a control system, an ultrasonic sensor stack to transmit ultrasonic waves through an acoustic resonator to a target object on an outer surface of an apparatus that includes the ultrasonic sensor stack and the acoustic resonator;
receiving, by the control system and from the ultrasonic sensor stack, ultrasonic sensor signals corresponding to reflections of transmitted ultrasonic waves from the target object; and
performing an authentication process based, at least in part, on the ultrasonic sensor signals, wherein the acoustic resonator comprises:
one or more higher-impedance layers having a thickness corresponding to a multiple of a half wavelength at a peak frequency of the acoustic resonator;
one or more first low-impedance layers residing between a first side of the one or more higher-impedance layers and the ultrasonic sensor stack, each layer of the one or more first low-impedance layers having a lower acoustic impedance than an acoustic impedance of the one or more higher-impedance layers, each layer of the one or more first low-impedance layers having a thickness corresponding to a multiple of a quarter wavelength at the peak frequency of the acoustic resonator; and
one or more second low-impedance layers residing proximate a second side of the one or more higher-impedance layers, each layer of the one or more second low-impedance layers having a lower acoustic impedance than the acoustic impedance of the one or more higher-impedance layers, each layer of the one or more second low-impedance layers having a thickness corresponding to the multiple of the quarter wavelength at the peak frequency of the acoustic resonator.

16. The method of claim 15 , wherein one or more of the one or more higher-impedance layers comprise glass.

17. The method of claim 15 , wherein one or more of the one or more higher-impedance layers comprise metal.

18. The method of claim 15 , wherein at least one of the one or more first low-impedance layers or the one or more second low-impedance layers comprises a plurality of layers and wherein the plurality of layers includes at least a first layer and a second layer, the first layer having a first acoustic impedance that is higher than a second acoustic impedance of the second layer.

19. The method of claim 15 , wherein the apparatus further comprises a display stack and wherein the one or more second low-impedance layers resides between the display stack and the one or more higher-impedance layers.

20. The method of claim 15 , wherein the apparatus is a mobile device that includes the ultrasonic sensor stack and the acoustic resonator.

21. An apparatus, comprising:
an ultrasonic sensor stack;
an acoustic resonator, including one or more high-impedance layers having a thickness corresponding to a multiple of a half wavelength at a peak frequency of the acoustic resonator; and
a display stack residing between the ultrasonic sensor stack and the acoustic resonator.

22. The apparatus of claim 21 , wherein one or more of the one or more high-impedance layers comprise glass.

23. The apparatus of clai

Assignees

• Qualcomm Inc

Inventors

• Strohmann Jessica Liu
• Panchawagh Hrishikesh Vijaykumar
• Kuo Nai-Kuei
• Lu Yipeng
• Lopez Ali
• Djordjev Kostadin Dimitrov

Classifications

• G06V40/1306 Primary

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

• B06B1/0688

  with foil-type piezoelectric elements, e.g. PVDF · CPC title

• H10K59/65

  OLEDs integrated with inorganic image sensors · CPC title

• B06B2201/70

  Specific application · CPC title

• G06V40/1329

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