Acoustic tweezers

Patent metadata

Field	Value
Publication number	US-11534761-B2
Application number	US-201816757160-A
Country	US
Kind code	B2
Filing date	Oct 23, 2018
Priority date	Oct 25, 2017
Publication date	Dec 27, 2022
Grant date	Dec 27, 2022

Abstract

Electroacoustic device that includes a body, an electrode to be electrically powered, named hot electrode, and an electrode to be electrically grounded, named ground electrode. The body includes a piezoelectric part or the electroacoustic device further including a piezoelectric part different from the body. The hot electrode includes a hot track spiraling around a spiral axis. The radial step between two consecutive coils of the hot track decreasing radially from the spiral axis. The hot electrode and the ground electrode are arranged on the piezoelectric part such as to define a wave transducer configured to generate a focalised ultrasonic vortex propagating in the body and/or, when a fluid medium is acoustically coupled with the electroacoustic device, in the fluid medium.

First claim

The invention claimed is:

1. Electroacoustic device comprising a body, an electrode to be electrically powered, named hot electrode, and an electrode to be electrically grounded, named ground electrode,
the body comprising a piezoelectric part or the electroacoustic device further comprising a piezoelectric part different from the body,
the hot electrode comprising a hot track spiraling around a spiral axis, the radial step between two consecutive coils of the hot track decreasing radially from the spiral axis,
the hot electrode and the ground electrode being arranged on the piezoelectric part such as to define a wave transducer configured to generate a focalised ultrasonic vortex propagating in the body and/or, when a fluid medium is acoustically coupled with the electroacoustic device, in said fluid medium.

2. Electroacoustic device according to claim 1 , wherein the wave transducer is configured for the body to be located in between the hot electrode and a focal locus of the focalised ultrasonic vortex.

3. Electroacoustic device according to claim 1 , wherein the ground electrode is provided on the face of the piezoelectric part wherein the hot track is provided.

4. Electroacoustic device according to claim 3 , wherein the ground track is provided on the face of the piezoelectric part opposite to the face wherein the hot track is provided.

5. Electroacoustic device according to claim 1 , wherein the piezoelectric part is different from the body, the body being arranged on a face of the wave transducer and is acoustically coupled with the wave transducer.

6. Electroacoustic device according to claim 1 , wherein the ground electrode comprises at least one ground track spiraling around the spiral axis.

7. Electroacoustic device according to claim 1 , comprising a plurality of at least N hot electrodes, with N being at least 2 and at least one electrode of the plurality comprising a hot track spiraling around the spiral axis.

8. Electroacoustic device according to claim 7 , wherein the ground track is provided between two adjacent hot tracks.

9. Electroacoustic device according to claim 7 , wherein the ground electrode comprises at least M ground tracks, with M being at least 2, each ground track defining at least one spiral coil, the radial step between two adjacent coils of two adjacent ground tracks decreasing from the spiral axis.

10. Electroacoustic device according to claim 7 , further comprising a control unit for electrically powering the hot electrodes and being configured for controlling each electrode pair consisting of a hot electrode and the ground electrode, such that said each pair generates a volume acoustic wave in the piezoelectric part, the phase shift between the volume acoustic waves generated by two adjacent electrodes pairs being of 2π/N.

11. Electroacoustic device according to claim 7 , wherein at least two hot electrodes each comprise a single hot track defining at least one spiral coil, the step distance between two adjacent coils of the two respective adjacent hot tracks decreasing from the spiral axis.

12. Electroacoustic device according to claim 7 , wherein two adjacent hot tracks are provided on the same face of the piezoelectric part or two adjacent hot tracks are provided on two opposite faces of the piezoelectric part.

13. Electroacoustic device according to claim 7 , wherein the ground electrode comprises a ground coating extending over a face of the piezoelectric part and superimposed with the hot track of each hot electrode of the plurality of N hot electrodes.

14. Electroacoustic device according to claim 13 , wherein the ground electrode is superimposed with at least two adjacent hot tracks of two adjacent electrodes of the plurality of hot electrodes, said adjacent hot tracks being provided on the same face of the piezoelectric part, and with a gap separating said two adjacent hot tracks.

15. Electroacoustic device according to claim 7 , wherein each ground track is completely superimposed with the hot track of a respective hot electrode of the plurality of hot electrodes, and vice-versa.

16. Electroacoustic device according to claim 7 , wherein the piezoelectric part is provided in between the gap between the hot tracks of two adjacent hot electrodes.

17. Electroacoustic device according to claim 1 , wherein the body comprises in the piezoelectric part, the hot electrode and the ground electrode comprising respective hot track and ground track provided on a same face of the body, both the hot track and ground track spiraling around the spiral axis Z.

18. Electroacoustic device according to claim 1 wherein the hot track draws a line along a polar coordinate R(θ), from a center C, said polar coordinate being obtained by solving equation (i)

ψ
0

=

μ

(
N
)

(

ψ
_

+
π

,

-

σ
_

N

)

-

α
⁡
(

ψ
_

+
π

,

-

σ
_

N

)

+

ω
⁢

s
ref

⁢

h
⁡
(

θ
,
φ
,

ψ
_

,

σ

Assignees

• Univ Lille
• Lille Ecole Centrale
• Centre Nat Rech Scient
• Univ Sorbonne

Inventors

• Baudoin Michaël Aymeric Cyril
• Bou Matar-Lacaze Olivier Khalil Nizar
• Riaud Antoine Jean-Pierre René
• Thomas Jean-Louis Pierre

Classifications

• B06B1/0644

  using a single piezoelectric element (B06B1/0688 takes precedence) · CPC title

• B06B3/04

  involving focusing or reflecting · CPC title

• G10K11/32

  characterised by the shape of the source · CPC title

• G02B21/32

  Micromanipulators structurally combined with microscopes · CPC title

• B01L99/00

  Subject matter not provided for in other groups of this subclass · CPC title