Ultrasonic transducer and manufacture method thereof

Patent metadata

Field	Value
Publication number	US-10134973-B2
Application number	US-201514651499-A
Country	US
Kind code	B2
Filing date	Mar 2, 2015
Priority date	Mar 2, 2015
Publication date	Nov 20, 2018
Grant date	Nov 20, 2018

Abstract

The present application relates to the technical field of transducer, it provides an ultrasonic transducer and the manufacture method therefore. The ultrasonic transducer comprises: a piezoelectric layer for radiating sound signal forward or backward, each side thereof being plated with an electrode; a matching layer arranged in the front of the piezoelectric layer and suitable for sending the forward sound signal; a tuning layer arranged on the back of the piezoelectric layer, wherein the piezoelectric layer is disposed between the tuning layer and the matching layer; a backing layer for absorbing the backward sound signal from the piezoelectric layer, wherein the backing layer is arranged against the piezoelectric layer on the tuning layer.

First claim

We claim:

1. An ultrasonic transducer comprising:
a piezoelectric layer for radiating sound signal forward or backward, each side of the piezoelectric layer being plated with an electrode;
a matching layer arranged in the front of the piezoelectric layer and suitable for transmitting the forward sound signal;
a tuning layer arranged on the back of the piezoelectric layer, wherein the piezoelectric layer is disposed between the tuning layer and the matching layer; and
a backing layer for absorbing the backward sound signal from the piezoelectric layer, wherein the backing layer is arranged against the piezoelectric layer on the tuning layer,
wherein an acoustic impedance of the piezoelectric layer is greater than an acoustic impedance of the matching layer, and an acoustic impedance of the matching layer is greater than an acoustic impedance of the tuning layer.

2. The ultrasonic transducer of claim 1 , wherein an acoustic impedance Z t of the tuning layer, an acoustic impedance Z b of the backing layer, and an acoustic impedance Z p of the piezoelectric layer satisfy the following relationships:

0
<

Z
t

<

Z
b

⁢

⁢
and
⁢

⁢
0

<

Z
t
2

Z
b

<

Z
p

.

3. The ultrasonic transducer of claim 2 , wherein the acoustic impedance of the tuning layer is in the range of from 1 to 4 MRayls.

4. The ultrasonic transducer of claim 1 , wherein the acoustic impedance Z t of the tuning layer, the acoustic impedance Z b of the backing layer, and the acoustic impedance z p of the piezoelectric layer satisfy the following relationships:

Z
t

>

Z
b

>

0
⁢

⁢
and
⁢

⁢

Z
t
2

Z
b

>

Z
p

>
0.

5. The ultrasonic transducer of claim 4 , wherein the acoustic impedance of the tuning layer is in the range of from 40 to 110 MRayls.

6. The ultrasonic transducer of claim 1 , wherein the thickness of the tuning layer is in the range of from ⅕ to ⅘ wavelength, wherein the wavelength is determined by the ratio of the sound speed in the tuning layer to the work frequency of the tuning layer.

7. The ultrasonic transducer of claim 6 , wherein the thickness of the tuning layer is ½ wavelength or ¼ wavelength.

8. A probe comprising an ultrasonic transducer, wherein the ultrasonic transducer comprises:
a piezoelectric layer for radiating sound signal forward or backward, each side of the piezoelectric layer being plated with an electrode;
a matching layer arranged in the front of the piezoelectric layer and suitable for transmitting the forward sound signal;
a tuning layer arranged on the back of the piezoelectric layer, wherein the piezoelectric layer is disposed between the tuning layer and the matching layer; and
a backing layer for absorbing the backward sound signal from the piezoelectric layer, wherein the backing layer is arranged against the piezoelectric layer on the tuning layer,
wherein an acoustic impedance of the piezoelectric layer is greater than an acoustic impedance of the matching layer, and an acoustic impedance of the matching layer is greater than an acoustic impedance of the tuning layer.

9. The probe of claim 8 , wherein the probe is a Doppler probe, one-dimensional array probe or multi-dimensional array probe.

10. The ultrasonic transducer according to claim 1 , wherein the tuning layer is made of epoxy resin, plastics and composite material filled with low density powder.

11. The ultrasonic transducer according to claim 1 , wherein the tuning layer and the backing layer constitute an acoustic structure on the back of the piezoelectric layer, and the effective acoustic impedance of this acoustic structure is defined as Z bprime , which is represented by:

Z
bprime

=

Z
t

×

Z
b

×

cos
⁡

(

2
⁢

⁢
π
⁢

⁢
f
×

l
v

)

+

j
×

Z
t

×

sin
⁡

(

2
⁢
π
⁢

⁢
f
×

l
v

)

Assignees

• Edan Instruments Inc

Inventors

• Wang Wenjuan
• Zhou Dan
• Ouyang Bo
• Mo Jianhua

Classifications

• B06B1/067 Primary

  which is used as, or combined with, an impedance matching layer · CPC title

• H01L41/27

  Electricity · mapped topic

• B06B1/0685

  on the back only of piezoelectric elements · CPC title

• H01L41/04 Primary

  Electricity · mapped topic

• H10N30/871 Primary

  Single-layered electrodes of multilayer piezoelectric or electrostrictive devices, e.g. internal electrodes · CPC title