Claims
- 1. A piezoelectric resonator comprising:
- a piezoelectric substrate; and
- an interdigital transducer which is formed on said substrate and has at least two resonance characteristics, said interdigital transducer comprising a pair of thinned-out comb-shaped electrodes each having a plurality of fingers protruding towards the other electrode, said fingers from said pair of electrodes being in mutually interlocking formation, at least one mutually adjacent pair of the fingers of one of said electrodes sandwiching therebetween two or more of the fingers of the other of said electrodes, said piezoelectric substrate and said interdigital transducer being capable of providing free-edge surface reflection.
- 2. The piezoelectric resonator of claim 1 wherein each of said fingers except those at both ends of said piezoelectric substrate have width equal to one-quarter of the wavelength of surface waves excited in regions between said fingers and mutually adjacent pairs of said fingers are separated by one-quarter of said wavelength.
- 3. The piezoelectric resonator of claim 1 comprising two interdigital transducers which are formed on said piezoelectric substrate and are connected to each other so as to form two resonant units each having two resonance characteristics.
- 4. A piezoelectric resonator comprising:
- a piezoelectric substrate; and
- an interdigital transducer which is formed on said substrate and has at least two resonance characteristics, said interdigital transducer comprising a pair of comb-shaped electrodes each having a plurality of parallel fingers protruding in rows towards the other electrode, each of the fingers from one of the electrodes being aligned with one of the fingers from the other electrode, the lengths along said fingers of regions where surface waves can be excited upon application of a voltage across said electrodes varying over said rows, said piezoelectric substrate and said interdigital transducer being capable of providing free-edge surface reflection.
- 5. The piezoelectric resonator of claim 4 wherein each of said fingers except those at both ends of said piezoelectric substrate have width equal to one-quarter of the wavelength of surface waves excited in regions between said fingers and mutually adjacent pairs of said fingers are separated by one-quarter of said wavelength.
- 6. The piezoelectric resonator of claim 4 comprising two interdigital transducers which are formed on said piezoelectric substrate and are connected to each other so as to form two resonant units each having two resonance characteristics.
Priority Claims (2)
Number |
Date |
Country |
Kind |
6-034415 |
Mar 1994 |
JPX |
|
6-067427 |
Apr 1994 |
JPX |
|
Parent Case Info
This is a continuation of application Ser. No. 08/385,847 filed Feb. 9, 1995, now abandoned.
US Referenced Citations (17)
Foreign Referenced Citations (3)
Number |
Date |
Country |
5145369 |
Jun 1993 |
JPX |
5291869 |
Nov 1993 |
JPX |
2000409 |
Apr 1977 |
GBX |
Continuations (1)
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Number |
Date |
Country |
Parent |
385847 |
Feb 1995 |
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