Fujitsu Corporation

Fujitsu Media Devices Limited

Other

Sumio Yamada

Noboru Wakatsuki

Yoshiro Fujiwara

Hiroshi Ishikawa

Masanori Yachi

Masaaki Ono

Yoshio Satoh

Yuji Kojima

Hiroshi Hoshino

Hiroshi Tanaka

Kazutugu Kikuchi

Motoi Yamauchi

Yoshitaka Takahashi

Tsutomu Miyashita

Yoshitaka Nakamura

Shigeo Tanji

Atsushi Machida

Kenji Nagata

Masanobu Yanagisawa

Hisanori Aizawa

Noboru Wakatuki

Kuninori Kawaura

Nobuko Ono, Legal Representative

Sen Minemura

An acceleration sensor that suppresses fluctuations in the offset voltage and with an enhanced temperature characteristic is provided. The acceleration sensor comprises an weight that is formed in the center of a semiconductor substrate; a frame that is formed at the circumference of the weight; a beam or diaphragm that connects the weight and frame; a detection element that is formed on the beam or diaphragm and which detects bending of the beam or diaphragm that corresponds with the applied acceleration; and a lead that is formed on the beam or diaphragm and which guides the detection output of the detection element to a pad that is provided on the frame, wherein a dummy lead comprising a plurality of dot patterns which are at least electrically independent of the lead formed on the beam or diaphragm is formed on the beam or diaphragm.

Acceleration sensor

A structure with superior shock resistance is proposed for a parasol-type acceleration sensor. The acceleration sensor comprises a support portion the lower end of which is fixed to a substrate; a beam portion on which a detection element for applying changes to an output signal in correspondence with strain caused by acceleration acting on the detection element is formed, one end of the beam portion being connected to the top part of the support portion; a suspended weight connected to the other end of the beam portion; and a stopper substrate with a window portion through which, in order to guide an output signal of the detection element via a pad that is formed on the upper end face of the support portion, a conductor lead that is connected to the pad passes. Overswing of the weight is limited by means of the stopper substrate.

A tuning-fork vibratory gyro has first and second arms and a base integrally connected to the first and second arms. The gyro includes drive electrodes used to generate tuning-fork vibrations due to a piezoelectric transversal effect, and detection electrodes provided on the first and second arms and used to output a detection voltage due to an angular velocity.

Tuning-fork vibratory gyro

A piezoelectric actuator includes a main driver electrode and a sensor electrode A feedback signal is generated from the sensor electrode in order to eliminate a primary vibration mode due to a primary resonance frequency. The main driver electrode extends to a fixture portion of the actuator, the fixture portion being fitted into a support member The extending portion of the main driver electrode eliminates the electromechanical coupling against a secondary vibration mode due to a second resonance frequency. Features of the piezoelectric actuator suppress the resonance phenomenon, thus improving the response characteristics of the actuator.

Piezoelectric actuator

An object of the present invention is to realize a resonator-type SAW filter permitting higher extra-passband suppressibility by minimizing occurrence of an unwanted spurious peak. A resonator-type SAW filter in which a plurality of SAW resonators each having reflectors and an interdigital transducer and being connected in series and parallel with the other, wherein in at least one of the SAW resonators, particularly in at least one of the SAW resonators connected in series with one another, an inter-electrode pitch &lgr;,in the reflectors has a different value from an inter-electrode pitch &lgr;,in the interdigital transducers.

Resonator-type surface-acoustic-wave filter for reducing the signal strength of a spurious peak

Tuning fork vibratory gyro utilizing a piezoelectric transversal effect

A detection circuit for a vibratory gyro includes a first circuit which detects a detection signal output from the vibratory gyro and produces an output signal indicative of an angular velocity applied to the vibratory gyro, and a second circuit which is operatively coupled to the first circuit and reduces a leakage component included in the detection signal.

Detection circuit for vibratory gyro and vibratory gyro device using the same

In a piezoelectric gyro, an amplifier,receives and amplifies a detected signal from detecting electrodes,through,, and a bandpass filter,extracts only a detection-side resonant frequency component from the amplified signal. The extracted resonant frequency component is phase-shifted by a phase-shifting circuit,, and the resultant signal is passed through a limiting resistor,to prepare a constant-current drive signal, and the drive signal is inputted to drive electrodes,through,. As a result, the piezoelectric gyro oscillates self-excitedly at the detection-side resonant frequency. The present invention provides a piezoelectric gyro capable of maintaining a high sensitivity with respect to a change in temperature by improving detection sensitivity.

Piezoelectric gyro and method of driving the piezoelectric gyro

A vibratory gyro including a tuning-fork vibrator having a piezoelectric member and a supporting member supporting the tuning-fork vibrator. The tuning-fork vibrator has a driving-side vibration mode and a detection-side vibration mode. The tuning-fork vibrator resonates in the driving-side vibration mode, and the tuning-fork vibrator and the supporting member resonate as a whole in the detection-side vibration mode.

Tuning-fork vibratory gyro and sensor system using the same

A vibratory gyro includes a tuning-fork vibrator having a piezoelectric member, and a supporting member supporting the tuning-fork vibrator. The tuning-fork vibrator has a driving-side vibration and a detection-side vibration. The turning-fork vibrator resonates in the driving-side vibration, and the turning-fork vibrator and the supporting member resonate as a whole in the detection-side vibration.

A piezoelectric resonator includes a base plate and a strip-type, energy trapping piezoelectric resonator chip mounted on the base plate. The piezoelectric resonator chip includes a piezoelectric chip plate and a pair of electrode patterns formed on the opposed main surfaces of the piezoelectric chip plate. One main surface of the piezoelectric chip plate faces the base plate and is parallel therewith, and a conductive layer is formed on each end of the main surface facing the base plate. The thickness of the conductive layer is greater than that of the electrode pattern so that the electrode pattern is separated from the base plate. The conductive layer is directly mounted onto a conductive portion of the base plate, so as to electrically connect the electrode pattern and the conductive portion of the base plate.

Method for producing a piezoelectric resonator

A piezoelectric resonator with a rectangular parallelepiped resonator. A lithium niobate single crystal is used as the resonator chip material. Each of the opposed main surfaces of the resonator chip is arranged to be a surface of a rotated Y-cut plate which is rotated 165.+-.5 degrees about an X-axis. The angle of the longitudinal direction of the resonator chip is arranged to be 90.+-.5 degrees with respect to the X-axis of the rotated Y-cut plate.

Piezoelectric resonator using 165.degree. Y-cut LiNbO.sub.3

A piezoelectric resonator chip which includes a piezoelectric chip plate and a pair of electrode patterns which is formed on the opposite surfaces of the piezoelectric chip plate, the electrode patterns face each other through the piezoelectric chip plate. At least one of the electrode patterns has an adjuster pattern which includes a narrow cutting pattern and a separation pattern which is connected to the electrode pattern through the cutting pattern and which faces the other electrode pattern.

Piezoelectric resonator chip and trimming method for adjusting the

A piezoelectric resonator which resonates in thickness shear mode. The piezoelectric resonator includes a strip shaped resonance chip made of an X-cut plate of lithium tantalate crystal and having a rectangular cross-section. Electrodes are formed at the center portion with respect to the longitudinal direction of the resonance chip on each of two X-plane surfaces. The width of the electrodes is equal to the width of the resonance chip. The longitudinal direction of the resonance chip inclines with respect to the Y-axis by an angle of 50.degree..+-.2' in the clockwise direction in the X-plane so as to make the longitudinal direction of the resonance chip coincide with the displacement direction of primary oscillation of the crystal. Optimal ratios of the dimensions of the resonance chip and terminal connectors at the ends of the resonance chip are given to reduce spurious response. The temperature characteristic is optimized by selecting rotation angles about the Y-and Z-axes in relation to the amount of trapped energy.

LiTaO.sub.3 Piezoelectric resonator

An acoustic surface wave device comprises a piezoelectric substrate (1), an input transducer (2), an output transducer (3) and acoustical absorbent layer patterns (5, 6) for absorbing undesired acoustic surface waves and bulk waves (S.sub.4, S.sub.5). Each of the acoustical absorbent layer patterns (5, 6) has zigzag-shaped or triangular shaped edges, i.e., a recess portion (R.sub.1, R.sub.3) and a protruding portion (R.sub.2, R.sub.4). The recess portion has a further recess portion (R.sub.1 ', R.sub.3 ') which is formed diagonally with respect to the propagation path of acoustic surface waves.

Growing community of inventors

Yokohama, Japan

Sumio Yamada