Probe tip ultrasonic transducers and method of manufacture

• US 4,911,172 A
• Filed: 03/28/1988
• Issued: 03/27/1990
• Est. Priority Date: 03/28/1988
• Status: Expired due to Term

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Telectronics Pacing Systems, Inc (Abbott Laboratories Incorporated)
• Inventors: Nasr, Saad, Bui, Tuan
• Primary Examiner(s): Jaworski, Francis
• Application Number:
  US07/174,740
• Time in Patent Office: 729 Days
• Field of Search: 128/662.05, 128/662.06, 73/622, 73/623
• US Class Current: 600/466
• CPC Class Codes: A61B 2017/00924 for ultrasonic waves
• CPC Class Codes: A61B 2090/3929 Active markers
• CPC Class Codes: A61B 8/12 in body cavities or body tracts, e.g. by using catheters catheters per se A61M25/00
• CPC Class Codes: B06B 1/0688 with foil-type piezoelectric elements, e.g. PVDF

Abstract

An improved ultrasonic transducer for a catheter tip has a thin strip of piezoelectric polymer film formed into a spiral ring and adhesively mounted on the support structure near the catheter tip. Electrical connection between the back face of the film and the support structure negative electrode is via capacitive coupling. Connection to the front face of the film is via a wire connected to the positive electrode of the catheter. A further embodiment suitable for a needle transducer is formed by coating the tip with a solution of PVDF co-polymer to form the actual transducer.

Claims

1. A biological probe enclosing first and second conductors and having a tip, the probe comprising an ultrasonic transducer formed from a piezoelectric material,

said piezoelectric material having the form of a spiral ring about said probe tip, said spiral ring having inner and outer surfaces,

said inner surface of said piezoelectric spiral ring being capacitively coupled to said first conductor,

said outer surface of said piezoelectric spiral ring being electrically coupled to said second conductor.

2. The biological probe of claim 1 wherein said piezoelectric spiral ring is connected to said probe tip by a low viscosity adhesive and said inner surface of said piezoelectric spiral ring is capacitively coupled through said low viscosity adhesive to said first conductor.

3. The biological probe of claim 2 further comprising an insulator coating said tip and forming an insulating film having the same approximate thickness as said spiral ring.

4. The biological prove of claim 3 having a flexible lead portion with an outer generally cylindrical surface and further comprising an ultrasonically substantially transparent insulator forming a shell having an outer surface approximately in line with the outer surface of the probe.

5. A biological probe having a flexible lead portion with an outer generally cylindrical surface enclosing inner and outer coaxial conductors and a tip, the probe comprising an omnidirectional ultrasonic transducer formed from a piezoelectric material,

said piezoelectric material having the form of a spiral ring of width approximately 0.7 to 1.0 mm wide about said probe tip and connected thereto by a low viscosity adhesive, said spiral ring having inner and outer surfaces,

said inner surface of said piezoelectric spiral ring being capacitively coupled through said low viscosity adhesive to said inner coaxial conductor,

said outer surface of said piezoelectric spiral ring being electrically coupled to said outer coaxial conductor,

an insulator coating said tip and forming an insulating film having the same approximate thickness as said spiral ring,

an ultrasonically substantially transparent insulator forming a tubular shell having an outer surface approximately in line with said outer surface of the probe.