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:
Mar. 15, 1994
Filed:
Jul. 16, 1992
Hisao Banno, Aichi, JP;
Yasuhiko Nakagawa, Aichi, JP;
NGK Spark Plug Co., Ltd., Aichi, JP;
Abstract
In radio communication equipment, a ladder-type piezo-electric filter is provided which operates in a high-frequency region of approximately 1.7 MHz-2 MHz. The filter is smaller than conventional ladder-type electric filters, less costly, and more easily handled and produced. In accordance with the present invention, rectangular piezo-resonators that longitudinally generate harmonic oscillation are used in the series and parallel branches of a ladder-type circuit. In each resonator, piezo-electric regions are formed by dividing surface electrodes with isolating slits. The slits are formed at the positions corresponding to the node points of the harmonic oscillation waveforms. For the piezo-resonators placed in the series branches of the ladder-type circuit, the piezo-electric regions are polarized in the same transverse direction. In each piezo-resonator used in a parallel branch, the piezo-electric regions are polarized in alternately opposite transverse directions. In addition, the divisional electrodes of the parallel branch piezo-resonators are bridged over with a suitable conductor, such as conductive paint, or the like.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile