Japan Aviation Electronics Industry, Limited

Kazuhiro Sakuma

Aritaka Ohno

Ryoji Kaku

Eiichi Asami

Kenji Kuramoto

Mitsuaki Kazou

Yasuo Shintani

Akihiro Tomioka

Yasuhiko Fukumoto

Hirohito Itoh

Hirohito Ito

Hisashi Yabe

In a fiber optic gyroscope in which light from a light source is split into two beams for supply to one and the other end of an optical fiber coil respectively, and the two beams having propagated through the optical fiber coil and emitted the one and the other end thereof are coupled together for supply to a photodetector, there are separately formed on an optical integrated circuit substrate two optical waveguide couplers, each comprising a trunk and a pair of branches extending therefrom. The pair of branches of a first one of the two optical waveguide couplers are connected to the light source and the photodetector, respectively, and the pair of branches of the second optical waveguide coupler are connected to the one and the other end of the optical fiber coil, respectively. The trunks of the first and second optical waveguide couplers are interconnected via a connecting optical fiber. The optical integrated circuit substrate is fixed to a reinforcing plate of a material which has a thermal expansion coefficient nearly equal to that of the optical integrated circuit substrate. The reinforcing plate is held on a support structure by flexible holding means.

Fiber optic gyroscope using optical waveguide couplers

A temperature-compensating circuit for a capacitive or prezoelectric resistive accelerometer comprising a flexure with torquer coils subjected to physical changes in response to the linear accelerations, capacitive or piezoelectric resistive elements for detecting strain of the flexure, elements for amplifying the detected output and a negative feedback amplifier for supplying the output to the torquer coils. The output of the piezoelectric resistive element and the resistance of the torquer coils are affected considerably by the temperature change whereby the gain of the feedback amplifier changes. Accordingly, in the circuit of the present invention, the temperature change in the total gain of the accelerometer is removed by adding resistance elements to the negative feedback amplifier so as to cancel the positive temperature coefficient of resistance of the torquer coil and other elements.

Temperature-compensating circuit for accelerometers

An accelerometer is composed of a pair of housings each of which forms a magnetic structure together with a permanent magnet and a flapper flexurally supported by hinge portions between the magnetic structures. The permanent magnet is secured to the housing of the magnetic structure by means of a spacer so as to prevent a harmful thermal stress which will be caused by the difference of thermal expansion between the magnet and the housing. A bobbin with a torquer coil is secured to the flapper by means of a base member to take no effect of thermal stress which will be caused by the difference between the materials of the bobbin and the flapper. The above elements are housed in a case which is installed in an instrument board so as to be unaffected by changes in temperature in surroundings of the accelerometer.

Accelerometer

An accelerometer comprises a pair of stators, a permanent magnet arranged within each of the stators, arcuate support portions diametrically opposed to each other on the surface of each stator, a pair of ring members each of which is positioned on the arcuate support portions of a stator, and a support ring with a flapper interposed between the support ring members. The flapper is connected to the supporting ring by two hinge portions. On each side of the flapper is a bobbin on which a coil is wound, the coils being connected to an external circuit. All of the component elements of the accelerometer are constructed and designed so as to avoid stress depending upon a change in ambient temperature.

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Akishima, Japan

Kazuhiro Sakuma