Flexible piezo-electric membrane

• US 5,230,921 A
• Filed: 08/04/1992
• Issued: 07/27/1993
• Est. Priority Date: 08/04/1992
• Status: Expired due to Fees

• Current Assignee: Black Tie Medical Incorporated
• Original Assignee: Black Tie Medical Incorporated
• Inventors: Schutz, Ronald W., Waltonen, James R.
• Primary Examiner(s): Lusigan, Michael
• Assistant Examiner(s): MAIORANA, DAVID MICHAEL
• Application Number:
  US07/924,833
• Time in Patent Office: 357 Days
• Field of Search: 427/100, 427/322, 367/180
• US Class Current: 427/100
• CPC Class Codes: A61B 8/08 Detecting organic movements or changes, e.g. tumours, cysts, swellings A61B8/02 - A61B8/06 take precedence
• 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
• CPC Class Codes: H10N 30/098 Forming organic materials

Abstract

A piezo-electric flexible membrane is formed by treating a perfluorinated membrane in order to produce a membrane having an electrical resistance greater than 1×10⁹ ohms. The resultant piezo-electric membrane may be used as an ultrasound transducer.

Claims

1. A method of making a piezo-electric flexible membrane comprising:

treating a perfluorinated membrane with a hydrogen scavenging compound;

doping the treated membrane with a cation donating substance; and

providing an electrical connection to the treated and doped membrane.

2. The method of claim 1 wherein the perfluorinated membrane has the following chemical structure:

##STR2##

3. The method of claim 1 wherein said treating is performed for about one minute.

4. The method of claim 1 wherein the hydrogen scavenging compound is taken from the group consisting of NaCO₃, CaCO₃, and K₂ HPO₃.

5. The method of claim 1 wherein said doping is performed for about 25 minutes.

6. The method of claim 4 wherein the cation donating substance is an organic dye.

7. The method of claim 5 wherein the organic dye is taken from the group consisting of yellow #2 dye, red #40 dye, green dye, and methyl blue #1 dye.

8. The method of claim 1 which is characterized by changing the electrical resistance of the perfluorinated membrane from ≧

2×

10⁶ Ω

to a resistance of <

1×

10⁹ Ω

.

9. The method of claim 1 wherein the piezo-electric membrane is characterized by a broadside piezo-electric response.

10. A method of making a piezo-electric flexible membrane comprising:

treating a perfluorinated membrane having an electrical resistance of ≧

2 ×

10⁶ Ω

to produce a piezo-electric membrane having an electrical resistance of >

1 ×

10⁹ Ω

.

11. The method of claim 10 wherein said treating includes treating the perfluorinated membrane with a hydrogen ion scavenging compound and doping the membrane with an organic dye.

12. The method of claim 11 wherein said treating with the hydrogen ion scavenging compound is performed for about one minute and wherein said doping with the organic dye is performed for about 25 minutes.

13. The method of claim 12 wherein the hydrogen scavenging compound is taken from the group consisting of NaCO₃, CaCO₃, and K₂ HPO₃ and the organic dye is taken from the group consisting of yellow #2 dye, red #40 dye, green dye, and methyl blue #1 dye.

14. The method of claim 11 wherein the perfluorinated membrane has the following chemical structure:

##STR3##