Nihon Dempa Kogyo Co., Ltd.

Morio Onoe

Shigetaka Kaga

Hitoshi Sekimoto

A piezoelectric plate in the piezoelectric sensor is obtained from a rotated Y-plate where a rotation angle around the X-axis is set according to a type of the piezoelectric crystalline material, a detection region is located on a surface parallel to an X-Z plane, and a transmitting and a receiving parts are opposite to each other at positions sandwiching the detection region along an X-axis direction of the piezoelectric plate. When a guided wave excited by applying a frequency signal from the transmitting part satisfies &#x3be;h=m&#x3c0;/(2&#x3bb;) (2h: thickness of the piezoelectric plate, &#x3be;: wave number in the X-axis, &#x3bb;: wave number in thickness direction normalized by &#x3be;, m: positive even number), the rotation angle satisfies the displacement of a P wave component of the guided wave becomes the maximum, or the displacement of the SH wave component of the guided wave becomes the maximum.

Piezoelectric sensor

To provide an elastic wave device that is small sized and in which a frequency fluctuation due to a change with time hardly occurs, and an electronic component using the above elastic wave device. A trapping energy mode portionprovided in an elastic wave waveguidemade of an elastic body material excites a second elastic wave being an elastic wave in an energy trapping mode by a specific frequency component included in a first elastic wave being an elastic wave in a zero-order propagation mode propagated from a first propagation mode portion, and a cutoff portionprovided in a peripheral region of the trapping energy mode portionhas a cutoff frequency being a frequency higher than that of the second elastic wave. A second propagation mode portion mode-converts the second elastic wave leaked through the cutoff portion to a third elastic wave being the elastic wave in the zero-order propagation mode to propagate the third elastic wave.

Elastic wave device and electronic component

To provide an elastic wave device that is small sized and in which a frequency fluctuation due to a change with time hardly occurs, and an electronic component using the above elastic wave device. A trapping energy mode portionprovided in an elastic wave waveguidemade of an elastic body material excites a second elastic wave being an elastic wave in an energy trapping mode by a specific frequency component included in a first elastic wave being an elastic wave in a first or higher-order propagation mode propagated from a first propagation mode portion, and a cutoff portionprovided in a peripheral region of the trapping energy mode portionhas a cutoff frequency being a frequency higher than that of the second elastic wave. A second propagation mode portion mode-converts the second elastic wave leaked through the cutoff portion to a third elastic wave being the elastic wave in the propagation mode to propagate the third elastic wave.

To provide an elastic wave device that is small sized and in which a frequency fluctuation due to a change with time hardly occurs, and an electronic component using the above elastic wave device. A trapping energy mode portionprovided in an elastic wave waveguidemade of a piezoelectric material excites a second elastic wave being an elastic wave in a trapping energy mode by a specific frequency component included in a first elastic wave being an elastic wave such as a SAW propagated from a first propagation mode portion, and a cutoff portionprovided in a peripheral region of the trapping energy mode portionhas a cutoff frequency being a frequency higher than that of the second elastic wave. A second propagation mode portion mode-converts the second elastic wave leaked through the cutoff portion to a third elastic wave being the elastic wave in the propagation mode to propagate the third elastic wave.

The outer shape of a quartz crystal blank is processed to have a predetermined shape, thereby providing an SC cut crystal resonator capable of reliably and reproducibly suppressing B mode resonance. In this SC cut crystal resonator, the surface of the quartz crystal orthogonal to the Y axis is rotated through 33&#xb0; to 35&#xb0; about the X axis and is then rotated from this rotated position through 22&#xb0; to 24&#xb0; about the Z axis, and a slender quartz crystal blank oblong in an X' axis direction is cut from the rotated surface. The end surface of the quartz crystal blank orthogonal to the Z&#x2032; axis is tilted in a direction rotated through +7&#xb0; to +13&#xb0; or &#x2212;7&#xb0; to &#x2212;13&#xb0; about the X&#x2032; axis.

Growing community of inventors

Setagaya-ku, Japan

Morio Onoe