PIEZOELECTRIC TRANSDUCER AND NOISE MAKING DEVICE UTILIZING SAME

• US 3,815,129 A
• Filed: 12/12/1972
• Issued: 06/04/1974
• Est. Priority Date: 08/20/1970
• Status: Expired due to Term

• Current Assignee: Yosemite, Investment, Inc.
• Original Assignee: Louis P. Sweany
• Inventors: Sweany, Louis P.
• Primary Examiner(s): Pitts, Harold I.
• Application Number:
  US05/314,469
• Time in Patent Office: 539 Days
• Field of Search: 340/388R,156R 333/72R 331/116R
• US Class Current: 340/384.6
• CPC Class Codes: B06B 2201/55 Piezoelectric transducer
• CPC Class Codes: G08B 3/10 using electric transmission; using electromagnetic transmission
• CPC Class Codes: H04R 17/00 Piezoelectric transducers; Electrostrictive transducers piezoelectric or electrostrictive elements in general H10N30/00; details of piezoelectric or electrostrictive motors, generators or positioners H10N30/00

Abstract

A noise making device, using a piezoelectric transducer, includes a piezoelectric element mechanically coupled to a substrate and an electrical circuit for energizing the transducer. The piezoelectric element includes a piezoelectric crystal, first and second electrode means carried by the crystal, and means dividing one of the electrode means into electrically isolated areas so as to provide a third electrode means.

Claims

1. A transducer comprising:

a. a diaphragm b. a piezoelectric element mechanically connected to said diaphragm comprising a disc shaped piezoelectric crystal, first and second sheets of electrically conductive material disposed on opposite sides of said disc shaped crystal, means dividing said first sheet into an electrically isolated island of said electrically conductive material, said island being of substantially smaller area than the remaining area of said first sheet, and c. electrical terminals electrically connected to said island, said remaining area, and said second sheet.

2. A transducer according to claim 1 wherein said island is substantially rectangular and extends from an area near the center of said first sheet to its outer periphery.

3. A piezoelectric transducer according to claim 1 wherein said diaphragm includes a metallic substrate to which said piezoelectric element is bonded.

4. A piezoelectric transducer according to claim 1 wherein said metallic substrate is brass.

5. A piezoelectric transducer according to claim 1 wherein said means dividing one of said electrode means includes a slit cut in said first sheet of electrically conductive material.

6. A piezoelectric transducer according to claim 1 wherein said electrically conductive material is silver.

7. A piezoelectric transducer according to claim 1 wherein said piezoelectric crystal is a lead, zirconium, titanium composite.

8. A noise making device comprising:

a. a piezoelectric transducer including a diaphragm;

a piezoelectric element mechanically connected to said diaphragm including a disc shaped piezoelectric crystal, first and second sheets of electrically conductive material disposed on opposite sides of said disc shaped crystal, means dividing said first sheet into an electrically isolated island of said electrically conductive material, said island being of substantially smaller area than the remaining area of said first sheet; and

electrical terminals electrically connected to said island, said remaining area of said first sheet and said second sheet, b. a transistor amplifier circuit connected to said piezoelectric transducer collector-emitter to said second sheet and said remaining area, and a feedback circuit connected base to said island.

9. A noise making device according to claim 8 wherein said island is substantially rectangular and extends from an area near the center of said first sheet to its outer periphery.

10. In a noise making device according to claim 8 wherein said amplifier means includes first and second transistors electrically coupled to provide a common-emitter amplifier means.

11. In a noise making device according to claim 10 wherein said first transistor is connected to said second sheet and said remaining area from collector and emitter respectively, the collector of said second transistor connected to the base of said first transistor, the emitter of said second transistor connected to the emitter of said first transistor, and said island is connected to the base of said second transistor.

12. In a noise making device according to claim 8 wherein said amplifier means includes a single transistor connected tO said second sheet and said remaining area from collector and emitter respectively and said island is connected to the base of said transistor.