Piezoelectric transducer
First Claim
1. A transducer element, comprising:
- (a) a cell member having a cavity;
(b) a flexible piezoelectric layer attached to said cell member so as to isolate said cavity from an external medium, said cavity having a lower acoustic impedance than said external medium, said piezoelectric layer having an external surface and an internal surface, and (c) a first electrode attached to said external surface and a second electrode attached to said internal surface.
1 Assignment
0 Petitions
Accused Products
Abstract
A miniature piezoelectric transducer element is provided, comprising: (a) a cell element having a cavity; (b) a flexible piezoelectric layer attached to the cell member, the piezoelectric layer having an external surface and an internal surface, the piezoelectric layer featuring such dimensions so as to enable fluctuations thereof at its resonance frequency upon impinging of an external acoustic wave; and (c) a first electrode attached to the external surface and a second electrode attached to the internal surface of the piezoelectric layer. At least one of the electrodes may be specifically shaped so as to provide a maximal electrical output, wherein the electrical output may be current, voltage or power. A preferred shape of the electrodes includes two cores interconnected by a connecting member. The transducer element may function as a transmitter. When used as a transmitter, the electrodes are electrically connected to an electrical circuit including a switching element for modulating the reflected acoustic wave by controllably changing the mechanical impedance of the piezoelectric layer according to the frequency of an electrical message signal arriving from an electronic member, such as a sensor. Third and fourth electrodes may be attached to the piezoelectric layer and the electrical circuit, such that the switching element alternately connects the electrodes in parallel and anti-parallel electrical connections so as to controllably change the mechanical impedance of the piezoelectric layer.
94 Citations
16 Claims
-
1. A transducer element, comprising:
-
(a) a cell member having a cavity;
(b) a flexible piezoelectric layer attached to said cell member so as to isolate said cavity from an external medium, said cavity having a lower acoustic impedance than said external medium, said piezoelectric layer having an external surface and an internal surface, and (c) a first electrode attached to said external surface and a second electrode attached to said internal surface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
-
-
14. A transmitter element comprising:
-
a cell member having a cavity;
a flexible piezoelectric layer attached to said cell member, said piezoelectric layer having an external surface and an internal surface; and
a first electrode attached to said external surface and a second electrode attached to said internal surface, said electrodes coupled to an electrical circuit, said electrical circuit having a switching element, whereby a switching frequency of said switching element controls the mechanical impedance of the piezoelectric layer, wherein the switching frequency of said switching element equals the frequency of an electrical message signal arriving from an electric member.
-
-
15. The transmitter element of claim 17, wherein said electronic member is a sensor.
-
16. A transmitter element comprising:
-
a cell member having a cavity;
a flexible piezoelectric layer attached to said cell member, said piezoelectric layer having an external surface and an internal surface, and a first electrode attached to said external surface and a second electrode attached to said internal surface, said electrodes coupled to an electrical circuit, said electrical circuit having a switching element, whereby a switching frequency of said switching element controls the mechanical impedance of the piezoelectric layer, wherein said switching element is for modulating a reflected acoustic wave according to a message signal arriving from an electronic component.
-
Specification