Micromachined imaging transducer

Abstract

The present invention generally relates to medical devices, and more particularly to an improved medical imaging device. In one embodiment, an imaging device includes a drive shaft having proximal and distal ends received within the lumen; and an imaging transducer assembly. coupled to the distal end of the drive shaft and positioned at the distal portion of the elongate member. The imaging transducer assembly includes one or more imaging transducers formed with a piezoelectric composite plate using photolithography based micromachining.

1 - 27 . (canceled) 
   
   
       28 . An imaging device configured to be located in an imaging catheter, said imaging device comprising:
 a drive shaft having proximal and distal ends; and   an imaging transducer assembly coupled to the drive shaft, wherein the imaging transducer assembly includes at least one imaging transducer, wherein the at least one imaging transducer is formed from a photolithography based micromachined piezoelectric composite plate, wherein each imaging transducer includes a plurality of posts and each of the plurality of posts has a vertical etching profile of at least 80°.   
   
   
       29 . The imaging device of  claim 28 , wherein the plurality of posts are separated from each other by a plurality of kerfs, wherein each post has a width in the range of 3 to 36 μm and each kerf has a width in the range of 1 to 15 μm. 
   
   
       30 . The imaging device of  claim 29 , wherein each post has a height in the range of 5 to 70 μm. 
   
   
       31 . The imaging device of  claim 30 , wherein each of the plurality of posts has an aspect ratio of post height to post width of at least 2 to 1. 
   
   
       32 . The imaging device of  claim 28 , wherein at least one of the at least one imaging transducer is in a 2-2 configuration or a 1-3 configuration. 
   
   
       33 . An ultrasound imaging transducer, comprising:
 a plurality of posts formed by photolithography based micromachining of a piezoelectric composite plate, wherein each of the plurality of posts has an aspect ratio of post height to post width of at least 2 to 1;   a plurality of kerfs separating the plurality of posts, wherein the plurality of kerfs are filled with a polymeric material; and   an electrode pattern coupled to the plurality of posts.   
   
   
       34 . The ultrasound imaging transducer of  claim 33 , wherein each post has a width in the range of 3 to 36 μm and each kerf has a width in the range of 1 to 15 μm. 
   
   
       35 . The ultrasound imaging transducer of  claim 34 , wherein each of the posts has a height in the range of 5 to 70 μm. 
   
   
       36 . The ultrasound imaging transducer of  claim 33 , wherein each of the posts has a vertical etching profile of at least 80°. 
   
   
       37 . The ultrasound imaging transducer of  claim 33 , wherein the transducer is configured and arranged to operate at a frequency of at least 20 MHz. 
   
   
       38 . The ultrasound imaging transducer of  claim 33 , wherein the transducer is configured and arranged to operate at a frequency of at least 100 MHz. 
   
   
       39 . The ultrasound imaging transducer of  claim 33 , wherein the piezoelectric composite plate is a single crystal piezoelectric. 
   
   
       40 . A ultrasound imaging transducer assembly, comprising:
 an array comprising a plurality of the ultrasound imaging transducers of  claim 33 .   
   
   
       41 . The ultrasound imaging transducer assembly of  claim 40 , wherein the array is a one dimensional array of the plurality of ultrasound imaging transducers. 
   
   
       42 . The ultrasound imaging transducer assembly of  claim 40 , wherein the array is a two dimensional array of the plurality of ultrasound imaging transducers. 
   
   
       43 . A method of fabricating an ultrasound imaging transducer, the method comprising:
 forming a photoresist mask on a plate of piezoelectric material;   forming a hard metal mask on portions of the plate exposed by the photoresist mask;   removing the photoresist mask leaving the hard metal mask;   etching portions of the plate exposed by the hard metal mask to form, in the plate, a plurality of posts and a plurality of kerfs between the posts, wherein each of the plurality of posts has an aspect ratio of post height to post width of at least 2 to 1; and   filling the plurality of kerfs surrounding the plurality of posts with a polymeric material.   
   
   
       44 . The method of  claim 43 , further comprising applying an electrode pattern to the plurality of posts. 
   
   
       45 . The method of  claim 43 , wherein etching portions of the plate comprises etching the portions of the plate to form the plurality of posts, wherein each post has a vertical etching profile of at least 80°. 
   
   
       46 . The method of  claim 43 , wherein the plate of piezoelectric material is a plate of a single crystal piezoelectric material. 
   
   
       47 . The method of  claim 43 , wherein filling the plurality of kerfs comprises applying a vacuum during the filling of the plurality of kerfs to remove air bubbles.