Abstract: Piezoelectric resonators utilizing a differentially offset reflector. One or more piezoelectric resonators are supported upon a substrate by one or more intervening layers of material, which intervening layers of material act as a reflector. The reflector isolates the resonators from the substrate. A portion of one or more of the intervening layers of material includes a differential layer of material, which differential layer shifts the resonant frequencies of the resonators that overlie the differential layer as compared with the resonant frequencies of those resonators that do not overlie the differential layer of material.

Abstract: An ultrasonic transducer having a narrow principal lobe opening angle simultaneously with low secondary lobe amplitudes is provided. The ultrasonic transducer invention has a disk-shaped quarter-wave transformer element whose peripheral surface is configured as a stepped profile.

Abstract: The present invention provides a piezoelectric acoustic device 2 capable of preventing substantial deflection of a first side wall 17 opposite a piezoelectric vibrator 13 due to application of force to an integral cylinder 12 in a direction toward the first side wall 17. According to the invention, a piezoelectric vibrator 13 including a piezoelectric ceramic element is received in a two-part receiving casing 9 formed by fitting a first casing half 10 and a second casing half 11 together. The first casing half 10 includes a first side wall 17 opposite to the piezoelectric vibrator 13 and a first peripheral wall 18 extending from the first side wall 17. A front air chamber 30 is defined between the first side wall 17 and the piezoelectric vibrator 13. A cylinder 12 is integrally formed on the first side wall 17 so as to extend in a direction perpendicular away from the plane of the first side wall 17.

Abstract: The invention concerns a resonator (1) with at least one crystal (2, 2'), at least two electrodes (3, 3', 4, 4') exciting the crystal (2, 2'), and a sandwich housing (5, 5') with a substantially plate-shaped bottom (6), at least one frame-like central portion (7, 7') which surrounds the crystal (2, 2') and supports it in a pendular fashion, and a substantially plate-shaped lid (8), wherein these housing sections (6, 7, 7', 8) are interconnected by means of sealing surfaces (13, 14, 15, 16), with the inclusion of conducting layers (9 and 9', 10 and 10'; 11, 12) and each electrode (3, 4; 3', 4') is connected to conductive layers (9 and 9', 10 and 10';11, 12). The resonator in accordance with the invention is configured in such a fashion that it can be further processed using SMD technology.