Audio speaker and proximity sensor with piezoelectric polymer technology

Patent metadata

Field	Value
Publication number	US-12284481-B2
Application number	US-202117302714-A
Country	US
Kind code	B2
Filing date	May 11, 2021
Priority date	May 29, 2020
Publication date	Apr 22, 2025
Grant date	Apr 22, 2025

Abstract

A mobile device includes one or more piezoelectric polymer layers underlying a display. The one or more piezoelectric polymer layers may be electrically driven to operate in either a d33 stretching mode or a d31 bending mode. The mobile device functions as an ultrasonic sensor in the d33 stretching mode and as an audio speaker/microphone or a proximity sensor in the d31 bending mode. The piezoelectric polymer layer operating in the d31 bending mode may be directly mechanically coupled to a display, indirectly mechanically coupled to the display and underlying an ultrasonic sensor stack, or integrated in the ultrasonic sensor stack. Signal performance of the piezoelectric polymer layer operating in the d31 bending mode may be enhanced or modulated by having a larger area, multiple layers, bi-pole or uni-pole driving with multiple layers, one or more stiff adhesives, a spacer layer, one or more mass features, a thin TFT layer, a thick piezoelectric polymer layer, or combinations thereof.

First claim

What is claimed is:

1. A mobile device comprising:
a platen;
a display underlying the platen;
a thin-film transistor (TFT) layer underlying the display, wherein the TFT layer comprises an array of pixel electrodes, wherein adjacent pixel electrodes are separated by voids or flexible material;
a first piezoelectric polymer layer adjacent to and coupled to the TFT layer;
an electrode layer adjacent to and coupled to the first piezoelectric polymer layer, wherein the first piezoelectric polymer layer is positioned between the electrode layer and the TFT layer, wherein the TFT layer, and the first piezoelectric polymer layer form an ultrasonic sensor configured to operate in a d33 stretching mode;
a second piezoelectric polymer layer underlying the display, wherein the second piezoelectric polymer layer is configured to operate in a d31 bending mode in a second frequency range between about 20 kHz and about 1 MHz to function as a contactless proximity or gesture detector; and
a stiff epoxy adhesive layer between the TFT layer and the display, wherein the stiff epoxy adhesive has a Young's modulus equal to or greater than about 1.0 GPa.

2. The mobile device of claim 1 , wherein the d33 stretching mode is configured to operate in a first frequency range between about 1 MHz and about 100 MHz.

3. The mobile device of claim 1 , wherein the second piezoelectric polymer layer is mechanically coupled to the display in a region of the display separate from a region occupied by the ultrasonic sensor.

4. The mobile device of claim 1 , wherein the second piezoelectric polymer layer is mechanically coupled to and underlying the ultrasonic sensor.

5. The mobile device of claim 1 , further comprising:
a spacer layer between the second piezoelectric polymer layer and the display, wherein the spacer layer includes a plastic, metal or glass material.

6. The mobile device of claim 5 , wherein the second piezoelectric polymer layer is configured to generate acoustic waves, wherein the spacer layer is configured to adjust a signal output of the acoustic waves generated by the second piezoelectric polymer layer in one or more frequency ranges and/or shift a peak frequency of the acoustic waves generated by the second piezoelectric polymer layer.

7. The mobile device of claim 5 , wherein a thickness of the spacer layer is at least two times greater than a thickness of the second piezoelectric polymer layer.

8. The mobile device of claim 1 , wherein a thickness of the TFT layer is at least two times less than a thickness of the platen.

9. The mobile device of claim 1 , further comprising:
one or more mass features attached to the second piezoelectric polymer layer, wherein the one or more mass features include a plastic, metal, or glass material.

10. The mobile device of claim 1 , wherein a major surface of the second piezoelectric polymer layer spans more than about 50% of the display.

11. The mobile device of claim 1 , further comprising:
a plurality of piezoelectric polymer layers underlying the second piezoelectric polymer layer.

12. The mobile device of claim 1 , wherein the each of first and second piezoelectric polymer layers comprises polyvinylidene fluoride (PVDF) or polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) copolymer, wherein the platen comprises a cover glass, wherein a thickness of the TFT layer is equal to or less than about 250 μm.

13. A mobile device comprising:
a platen;
a display underlying the platen;
a thin-film transistor (TFT) layer underlying the display, wherein the TFT layer comprises an array of pixel electrodes, wherein each of the pixel electrodes has one or more voids or one or more filled voids with flexible material;
a first piezoelectric polymer layer adjacent to and coupled to the TFT layer;
an electrode layer adjacent to and coupled to the first piezoelectric polymer layer, wherein the first piezoelectric polymer layer is positioned between the electrode layer and the TFT layer, wherein the TFT layer, and the first piezoelectric polymer layer form an ultrasonic sensor configured to operate in a d33 stretching mode;
a second piezoelectric polymer layer underlying the display, wherein the second piezoelectric polymer layer is configured to operate in a d31 bending mode in a second frequency range between about 20 kHz and about 1 MHz to function as a contactless proximity or gesture detector; and
a stiff epoxy adhesive layer between the TFT layer and the display, wherein the stiff epoxy adhesive has a Young's modulus equal to or greater than about 1.0 GPa.

Assignees

• Qualcomm Inc

Inventors

• Strohmann Jessica Liu
• Panchawagh Hrishikesh Vijaykumar
• Buchan Nicholas Ian
• Lu Yipeng
• Djordjev Kostadin Dimitrov

Classifications

• H10N30/857

  Macromolecular compositions · CPC title

• G06V40/1306

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

• H04R17/02

  Microphones · CPC title

• H04R2499/15

  Transducers incorporated in visual displaying devices, e.g. televisions, computer displays, laptops · CPC title

• H04R2499/11

  Transducers incorporated or for use in hand-held devices, e.g. mobile phones, PDA's, camera's · CPC title