Piezoelectric transducer with multiple electrode areas
First Claim
1. A piezoelectric electro-acoustic transducer comprising:
- a flexible diaphragm including a flexible piezoelectric film fixedly supported at the periphery thereof, a first electrode on one side of said flexible piezoelectric film, and a plurality of second electrodes on the other side of said flexible piezoelectric film and confronting said first electrodes through said film, two said second electrodes on said other film side being spaced from each other and being arranged for electrical connection separately, said two second electrodes occupying two discreet areas on said film;
a resilient backing member backing said flexible diaphragm and supporting same in a nonplanar rest shape while imparting a limited and differing degree of stiffness to said two second electrode areas, said resilient backing member comprising two portions of different resiliencies which confront and support said two second electrode areas respectively, said two resilient backing member portions having geometric outlets substantially conforming to the outlines of the respective two said second electrodes, said two resilient backing member portions so differing from each other in structure as to impart different time constants to said two second electrode areas respectively, said transducer having a frequency range in which one of said two second electrode areas on said film is the more effective for frequencies in the lower part of said range and the other of said two second electrode areas on said film is the more effective for frequencies in the upper part of said range.
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Abstract
An electro-acoustic transducer comprising a flexible film of piezoelectric material, at least one electrode provided on one side of said film amd a plurality of electrodes provided on the other side of said film to form a piezoelectric diaphragm and said piezoelectric diaphragm is imparted with a locally differing resiliency and/or tension, is provided. By using this piezoelectric electro-acoustic transducer in a loudspeaker, it is possible to improve acoustic characteristics thereof particularly in a high frequency range, to obtain a variety of acoustic characteristics and to effect motional feed back to minimize distortion of reproduced sound without involving any difficulty in manufacturing or affecting proper performance of the transducer.
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Citations
9 Claims
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1. A piezoelectric electro-acoustic transducer comprising:
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a flexible diaphragm including a flexible piezoelectric film fixedly supported at the periphery thereof, a first electrode on one side of said flexible piezoelectric film, and a plurality of second electrodes on the other side of said flexible piezoelectric film and confronting said first electrodes through said film, two said second electrodes on said other film side being spaced from each other and being arranged for electrical connection separately, said two second electrodes occupying two discreet areas on said film; a resilient backing member backing said flexible diaphragm and supporting same in a nonplanar rest shape while imparting a limited and differing degree of stiffness to said two second electrode areas, said resilient backing member comprising two portions of different resiliencies which confront and support said two second electrode areas respectively, said two resilient backing member portions having geometric outlets substantially conforming to the outlines of the respective two said second electrodes, said two resilient backing member portions so differing from each other in structure as to impart different time constants to said two second electrode areas respectively, said transducer having a frequency range in which one of said two second electrode areas on said film is the more effective for frequencies in the lower part of said range and the other of said two second electrode areas on said film is the more effective for frequencies in the upper part of said range. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification