Ultrasound transducer and method for making the same

Patent metadata

Field	Value
Publication number	US-2016288168-A1
Application number	US-201615091284-A
Country	US
Kind code	A1
Filing date	Apr 5, 2016
Priority date	Sep 20, 2011
Publication date	Oct 6, 2016
Grant date	—

Abstract

The present application provides a multilayer lateral mode coupling method for phased array construction and transducer devices built accordingly. This disclosure describes and demonstrates that the electrical impedance of a phased array can be substantially reduced and readily controlled to be close to the source impedance. The fabrication process is relatively simple and inexpensive. In addition, the elements are robust for use in 1.5, 2, 3 or other dimensional configurations, over an extended period of operation, without structural failure, and providing a high power output required for imaging and/or medical therapy applications.

First claim

What is claimed is:

1 . An ultrasound transducer element comprising:
a piezoelectric stack comprising an even number of piezoelectric layers stacked along a first direction, said piezoelectric stack comprising a pair of outer electrodes formed on respective outer surfaces thereof, wherein each pair of adjacent piezoelectric layers within said piezoelectric stack are separated by, and mutually contact, a respective common electrode provided therebetween such that said outer electrodes and said common electrodes form a set of electrodes, each adjacent pair of electrodes having a respective piezoelectric layer provided therebetween; wherein odd-numbered electrodes, counted from a given side of said piezoelectric stack, are connected in parallel to form a common ground electrode, and even-numbered electrodes are connected in parallel to form a common signal electrode; such that, upon application of an electrical driving signal between said common ground electrode and said common signal electrode at a frequency associated with a lateral mode coupled resonance of said piezoelectric stack, lateral mode coupling causes said piezoelectric stack to be mechanically responsive along a second direction that is perpendicular to the first direction, thereby producing ultrasound emission along the second direction through an emitting surface of said ultrasound transducer element located at a first end of said ultrasound transducer element; and wherein said even-numbered electrodes extend from a second end of said piezoelectric stack in direction parallel to the second direction and are brought into electrical communication beyond the distal end of said piezoelectric stack.

2 . The ultrasound transducer element according to claim 1 wherein said even-numbered electrodes that extend from said second end contact low-temperature solder, thereby forming said common signal electrode.

3 . The ultrasound transducer element according to claim 1 wherein said common ground electrode extends parallel to said emitting surface at said first end of said ultrasound transducer element.

4 . The ultrasound transducer element according to claim 1 wherein said piezoelectric layers have equal lengths along the second direction.

5 . The ultrasound transducer element according to claim 1 wherein two or more of said piezoelectric layers have different lengths along the second direction, such that said piezoelectric layers having different lengths resonate at different frequencies via lateral mode coupled excitation.

6 . The ultrasound transducer element according to claim 5 wherein the different lengths are selected such that said ultrasound transducer element exhibits a combined wideband operation.

7 . The ultrasound transducer element according to claim 1 wherein said piezoelectric stack has a square cross-sectional shape perpendicular to the second direction.

8 . A phased-array ultrasound device comprising a one-dimensional array of ultrasound transducer elements formed according to claim 1 .

9 . A phased-array ultrasound device comprising a two-dimensional array of ultrasound transducer elements formed according to claim 1 , wherein said ultrasound transducer elements are arranged such that said common signal electrodes are individually addressable at a back side of said two-dimensional array, wherein said back side is associated with said second ends of said ultrasound transducer elements.

10 . The phased-array ultrasound device according to claim 9 wherein said ultrasound transducer elements are arranged such that said outer electrodes provide electrical connections among said common ground electrodes of said ultrasound transducer elements.

11 . A method for fabricating an ultrasound array of transducer elements, comprising:
providing a plurality of ultrasound transducer elements, each having a respective plurality of dimensions defining its spatial extent, including a first dimension along a first axis along which said ultrasound transducer element radiates ultrasound energy when excited by an electrical driving signal applied along a second axis that is perpendicular to said first axis, each ultrasound transducer element having a signal electrode and a ground electrode; mechanically arranging said plurality of ultrasound transducer elements along at least a direction perpendicular to said first axis; providing a plurality of conducting foils acting as electrodes to deliver electrical driving signals to the ultrasound transducer elements, said conducting foils interspersed between said plurality of ultrasound transducer elements such that ground electrodes of an adjacent pair of transducer elements share a common ground electrode lying between said pair of adjacent transducers; and driving said plurality of ultrasound transducer elements with electrical driving signals through signal electrodes and said common ground electrode.

12 . The method of claim 11 , said arranging comprising arranging the ultrasound transducer elements along a single axis with respect to one another.

13 . The method of claim 11 , said arranging comprising arranging the ultrasound transducer elements along two dimensions, both being perpendicular to said first axis.

14 . The method of claim 13 , further comprising application of low temperature solder to a surface of said array so as to couple the ultrasound transducer elements thereto.

Assignees

• Sunnybrook Res Inst

Inventors

• Hynynen Kullervo
• Song Junho

Classifications

• B06B1/0622 Primary

  on one surface · CPC title

• A61N7/02

  Localised ultrasound hyperthermia · CPC title

• Y10T29/49005

  Acoustic transducer · CPC title

• A61B8/4488

  the transducer being a phased array · CPC title

• H01L41/29

  Electricity · mapped topic