The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 02, 2000
Filed:
Apr. 16, 1998
Hitoshi Yanagihara, Kamakura, JP;
Takashi Shiba, Yokosuka, JP;
Katsumi Itoh, Yokohama, JP;
Akitsuna Yuhara, Tokyo, JP;
Hitachi Media Electronics Co., Ltd., Iwate-ken, JP;
Abstract
There is provided a surface acoustic wave device for use as a filter in a television receiver set which can reduce reflection waves generated from outermost electrodes of input and output interdigital transducers to improve various filter characteristics. In the surface acoustic wave device having, on a piezoelectric substrate, the input interdigital transducer for converting an electric signal into a surface acoustic wave and the output interdigital transducer, disposed to oppose the input interdigital transducer, for converting the surface acoustic wave resulting from the conversion by the input interdigital transducer into an electric signal, a first dummy electrode is provided to a first outermost electrode finger of the output interdigital transducer, the first outermost electrode finger being located at one end of the output interdigital transducer opposite to the input interdigital transducer, and having an electrode aperture length of .lambda./4 where n represents a wavelength of the surface acoustic wave, and a second dummy electrode is provided to a second outermost electrode finger of the input interdigital transducer, the second outermost electrode finger being located at one edge of the input interdigital transducer opposite to the output interdigital transducer, and having an electrode aperture length of .lambda./4.