Ultrasonic transducer for a metallic cavity implated medical device

• US 7,949,396 B2
• Filed: 07/20/2007
• Issued: 05/24/2011
• Est. Priority Date: 07/21/2006
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Chavan, Abhijeet V., Maile, Keith R., Mi, Bin
• Primary Examiner(s): Getzow; Scott M
• Assistant Examiner(s): PATTON, AMANDA K
• Application Number:
  US11/780,992
• Publication Number:
  US 20080021509A1
• Time in Patent Office: 1,404 Days
• Field of Search: 607 36- 37, 607/2, 607/32
• US Class Current: 607/36
• CPC Class Codes: A61B 5/0028 Body tissue as transmission medium, i.e. transmission systems where the medium is the human body
• CPC Class Codes: A61N 1/37217 characterised by the communication link, e.g. acoustic or tactile
• CPC Class Codes: A61N 1/37288 Communication to several implantable medical devices within one patient

Abstract

An implantable medical device comprising a housing and an ultrasonic transducer having a communication frequency coupled to a portion of the housing. The housing resonates at the communication frequency, and a casing is coupled to the housing and disposed over the ultrasonic transducer. The casing is adapted to amplify the deformation of the ultrasonic transducer in a bending mode and transfer the bending moment to the housing. An implantable medical device comprising a housing having an upper portion and a lower portion. A first ultrasonic transducer is coupled to a first connection rod and is coaxial with the first connection rod. The first ultrasonic transducer and first connection rod are interposed between the upper and lower portions such that the first ultrasonic transducer is adapted to vibrate the upper and lower portions simultaneously. A method of optimizing an ultrasonic transducer and a housing of an implantable medical device.

Claims

1. An implantable medical device comprising:

a housing;

an ultrasonic transducer coupled to a portion of the housing and disposed inside the housing, the transducer having a communication frequency, wherein the housing resonates at the communication frequency; and

a casing coupled to the housing and disposed over the ultrasonic transducer, wherein the casing is adapted to amplify the deformation of the ultrasonic transducer in a bending mode and transfer the bending moment to the housing.

2. The implantable medical device of claim 1 wherein the implantable medical device comprises a pulse generator.

3. The implantable medical device of claim 1 wherein the ultrasonic transducer comprises a piezoelectric material.

4. The implantable medical device of claim 3 wherein the piezoelectric material comprises polyvinylidine diflouride (PVDF) material.

5. The implantable medical device of claim 3 wherein the ultrasonic transducer comprises lead magnesium niobate—

lead titanate (PMN-PT).

6. The implantable medical device of claim 3 wherein the piezoelectric material comprises a lead zirconate titanate (PZT) material.

7. The implantable medical device of claim 6 wherein the ultrasonic transducer has a circular shape, a diameter of approximately 25.4 millimeters or less, and a thickness of approximately 3 millimeters or less.

8. The implantable medical device of claim 1 wherein the casing has a diameter of greater than approximately 25.4 millimeters, a height of less than approximately 4 millimeters, a top thickness of between approximately 0.2 and 1 millimeter, and a wall thickness of between 3 and 6 millimeters.

9. The implantable medical device of claim 1 wherein the ultrasonic transducer has a mechanical resonance of greater than approximately 20 kiloHertz.

10. The implantable medical device of claim 1 wherein the ultrasonic transducer has a mechanical resonance of approximately 40 kiloHertz.

11. The implantable medical device of claim 1 wherein the housing includes thinned regions having a thinner cross-section than a substantial portion of the housing and the ultrasonic transducer is located adjacent to the thinned regions.

12. The implantable medical device of claim 11 wherein the thinned regions have an annular shape.

13. The implantable medical device of claim 11 wherein the thinned regions have a wavy or corrugated shape.

14. An implantable medical device comprising:

a housing having an upper portion and a lower portion;

a first ultrasonic transducer coupled to a first connection rod and coaxial with the first connection rod;

wherein the first ultrasonic transducer and first connection rod are interposed between the upper and lower portions, such that the first ultrasonic transducer is configured to propagate acoustic waves in a first direction towards the upper portion of the housing and a second direction towards the lower portion of the housing, the first ultrasonic transducer configured to vibrate the upper and lower portions simultaneously.

15. The implantable medical device of claim 14 wherein the implantable medical device further comprises a second ultrasonic transducer coaxial with the first ultrasonic transducer and the first connection rod and interposed between the upper and lower portions.

16. The implantable medical device of claim 14 wherein the implantable medical device further comprises a second connection rod coaxial with the first ultrasonic transducer and the first connection rod and interposed between the upper and lower portions.

17. The implantable medical device of claim 14 wherein the implantable medical device further comprises a second connection rod and a second ultrasonic transducer coaxial with the first ultrasonic transducer and the first connection rod and interposed between the upper and lower portions.

18. The implantable medical device of claim 14 wherein the combined thickness of the first connection rod and the first ultrasonic transducer is between approximately 6 and 7 millimeters.

19. The implantable medical device of claim 14 wherein the first ultrasonic transducer comprises a lead zirconate titanate (PZT) material having a diameter of approximately 1 centimeter and a height of approximately 1 millimeter, the connection rod has a height of approximately 6 millimeters, a minimum diameter of approximately 1 centimeter, a maximum diameter of approximately 2.5 centimeters, and a taper beginning at a height of approximately 3 millimeters, and the thickness of the housing is between 0.3 to 2 millimeters and the width of the housing is between about 2.5 to 5 centimeters.