Denso Corporation

Kazuki Arakawa

Kazuhiko Kano

Akihiko Teshigahara

Kazushi Asami

Shingo Jinno

In a SAW oscillator, each of a first SAW element and a second SAW element includes interdigital electrodes and a reflector formed on a piezoelectric material. A first oscillating circuit part forms an oscillating loop including the first SAW element. A second oscillating circuit part forms an oscillating loop including the second SAW element. The first and second oscillating circuit parts have an identical admittance property. The first and second SAW elements are configured that an electrode pitch is identical and an admittance property indicating a relation between a frequency and an admittance value is different therebetween. Further, a first intersection point between the admittance property of the first SAW element and the admittance property of the first oscillating circuit part and a second intersection point between the admittance property of the second SAW element and the admittance property of the second oscillating circuit part are at different frequencies.

Surface acoustic wave oscillator

An angular rate sensor comprises a piezoelectric film having a first and a second surfaces forming an x-y plane and utilizes a perturbation mass coherently vibrating elastic acoustic waves on which a Coriolis force acts when the angular rate sensor undergoes a rotary motion about an x-direction. A first elastic acoustic wave is excited in the piezoelectric film by a driving transducer and a second elastic acoustic wave generated by the Coriolis force proportional to an angular rate of the rotary motion of the angular rate sensor itself is detected by the detecting transducer. The angular rate sensor further comprises at least a first electrode disposed on the first surface of the piezoelectric film for discharging a surface charge caused due to piezoelectric effect at the lower surface of the film in which the first elastic acoustic wave is excited.

Angular rate sensor

A surface acoustic wave element includes a piezoelectric member, a comb-teeth electrode, and a reflector. The comb-teeth electrode is arranged on the piezoelectric member. The reflector is arranged on the piezoelectric member. The reflector reflects a surface acoustic wave transmitted from the comb-teeth electrode. The reflector has a plurality of areas, and each of the areas has a frequency to make a reflection efficiency the largest. At least two of the frequencies of the areas are made different from each other.

Surface acoustic wave element, method of producing the same, and method of changing resonation frequency of the same

A yaw rate sensor has two sets of exciting electrodes, perturbative weights and two sets of detecting electrodes on a surface of a piezoelectric substrate. The exciting electrodes excite first surface acoustic waves transmitted through the surface of the substrate in a propagation direction. The weights are oscillated by the waves and excite a second surface acoustic wave, transmitted through the surface of the substrate in a detection direction orthogonal to the propagation direction, in response to a yaw applied to the weights. The detecting electrodes measure an intensity of the second surface acoustic wave to detect the yaw rate. The sets of exciting electrodes are symmetrically placed with respect to a driving axis extending straight along the propagation direction. The group of weights is symmetric with respect to the driving axis.

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Nisshin, Japan

Kazuki Arakawa