JPS58190773A - Detector for angular velocity of rotation - Google Patents

Abstract

PURPOSE:To detect the angle of rotation at a high accuracy by covering a coil- shaped light transmission path with a magnetism shielding material to reduce effect of an external magnetic field. CONSTITUTION:In a detector for angular velocity of rotation adapted to detect phase difference employing an output signal of a light detector 4, all parts containing a coil-shaped light transmission path 3 is covered with magnetism shielding cases 5 using permalloy. This prevents application of any external magnetic field and hence can minimize the rotation of plane of polarization due to Faraday effect generating according to the intensity of a magnetic field thereby enabling the measurement of angular velocity of rotation at a high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical rotational angular velocity detector using a ring interferometer.

It is believed that a ring interference needle with a long optical transmission path as an optical path acts as a rotation meter for inertial space, and can constitute a highly sensitive optical gyroscope. Compared to conventional mechanical gyroscopes that use the rotation of a rotor, there are no rotating parts, so they have a long life and are highly reliable, so their practical use is desired.

The principle behind this is known as the Sagnac effect, where two beams of light propagate in opposite directions. i! It is based on the fact that there is a difference in propagation time that is proportional to the dynamic velocity. However, since the phase difference caused by the Sagnac effect is very small, it is necessary to use a long optical transmission path and to accurately measure the slight phase difference. Therefore, slight deformation of the optical transmission line etc.1
There are isolated points where large errors occur due to changes in propagation speed, propagation loss, or plane of polarization caused by this. Therefore, it is necessary to prevent deformation of the optical transmission path, but errors may also occur due to other non-mechanical disturbances, especially magnetic disturbances.

Therefore, an object of the present invention is to provide a rotational angular velocity detector that can accurately detect rotational angular velocity without being affected by such magnetic disturbances.

The rotational angular velocity detector of the present invention includes a light source, a coiled optical transmission line, means for dividing light into seven parts and inputting the light from both ends of the optical transmission line, The rotational angular velocity detector has a means for detecting a phase difference between two lights, and is characterized in that at least a portion of the coiled optical transmission path is covered with a magnetic shielding material.

With this configuration, even if a magnetic field is applied from the outside, since it is magnetically shielded, only a very small magnetic field is applied to the optical path itself, and therefore, it can be made small to the extent that it does not deflect.

Next, the present invention will be described in detail with reference to the drawings.

FIG. 1 conceptually shows the configuration of a rotational angular velocity detector used in the present invention.

The light source 1 is a single wavelength laser generator, and its output light 1
01 corresponds to semi-transparent @2, and some of the light transmitted through it is 10
2 enters the optical transmission line 3 from the end face 31, while the semi-transparent mirror 2
The reflected light 103 enters the optical transmission line 3 from the other end face 32. The light beams 102 and 103 incident from both end surfaces 31 and 32 propagate through the coiled light transmission M3 A, and then are emitted from the opposite end surfaces 32 and 31. The in-phase component is divided into one light source. With this configuration, the rotational angular velocity can be determined by detecting the phase difference using the output (g) of the light emitting device 4.

The above is a ring interference i used as a rotational angular velocity detector.
This is a general explanation of the expert.

Kimi ψ40) The first embodiment is a rotational angular velocity detector as described above, in which a portion including a coiled optical transmission line is covered with an air tracing case 5 made of permalloy. (A light source and a photodetector may be used together with the optical transmission line.) This makes it possible to ensure that almost no magnetic field is applied to the optical transmission line itself even if an external magnetic field is applied. Therefore, the rotation of the plane of polarization due to the Faraty effect that occurs depending on the magnetic field strength can be reduced to the extent that it does not pose a problem in practice, so that the rotational angular velocity can be measured with high accuracy.

FIG. 2 is a diagram showing a cross-sectional structure of an optical transmission line used in a second embodiment of the present invention. In this embodiment, a magnetic S-shielding layer 7 made of permalloy is provided on the outside of an ordinary glass optical fiber 6 consisting of a core portion 61 and a cladding portion 62 through which light propagates.
A8 was formed and then coated with resin. With the method of this embodiment, as in the first embodiment, the rotational angular velocity can be detected with high precision while avoiding the influence of external magnetic fields.

In each of the above embodiments, a semiconductor laser, a gas laser, etc. can be used as the light source, and various high magnetic permeability materials other than permalloy can be used as the magnetic S shielding material.

Furthermore, in each of the above embodiments, a configuration for directly detecting a phase difference has been described, but the present invention can also be applied to cases where phase modulation is used, a heterodia system is used, a frequency shifter is used, etc. apply l
This allows the rotational angular velocity to be measured with high accuracy while avoiding the influence of disturbances caused by external magnetic fields.

As detailed above, according to the present invention, by covering at least the portion of the coiled optical transmission path with the air shielding material, the influence of external magnetic fields is greatly reduced, and the rotational angular velocity can be detected with high accuracy. It is possible to provide a rotational angular velocity detector capable of

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram showing the configuration of a rotational angular velocity detector according to a first embodiment of the present invention, and FIG. 2 is a sectional view of an optical transmission line used in the second embodiment of the present invention. 1. Light source 2... Translucent bell 3... Optical transmission line 4 Photodetector 5 4a air shielding case 6...
...Optical fiber 7... Magnetic lotus shielding layer

Claims (1)

[Claims] f. A light source, a coiled optical transmission line, a means for partially transmitting light to enter from both ends of the mosquito optical transmission line, and detecting the phase difference between the two lights emitted from both ends of the optical transmission line. 1. A rotational angular velocity detector comprising: at least a portion of the coiled optical transmission path covered with a magnetic shielding material.