JPH08304082A - Optical rotational angle sensor - Google Patents

Abstract

PURPOSE: To obtain a small-sized inexpensive optical rotational angle sensor which can be manufactured easily by winding the optical fibers interconnecting a light source, an optical fiber coupler, a phase modulator and a sensing group, along the sensing group. CONSTITUTION: Optical fibers of a light source 1, an optical fiber coupler 2, a phase modulator 3 and a sensing group 4 are connected to each other at their ends 5, and the joints are reinforced using sleeves 6 thus constituting an optical system. Each end 5 of thus connected optical fibers forms an extra length part 7. The phase modulator 3 and sensing group 4 in the optical system are contained in an optical system containing pan 8. The pan 8 comprises an outer tubular part 9 larger than the outside diameter of the sensing group 4 and an inner tubular part 10 smaller than the outside diameter of the sensing group 4 but larger than the outside diameter of the phase modulator 3. Consequently, the sensing group 4 is contained between the outer tubular part 9 and the inner tubular part 10 and the phase modulator 3 is contained in the inner tubular part 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical rotation angle sensor formed by connecting optical devices with an optical fiber, and more particularly to a small and inexpensive optical rotation angle sensor that can be easily manufactured.

[0002]

2. Description of the Related Art As shown in FIG. 3, a phase modulation type optical rotation angle sensor has an optical system in which a light source 1 and light from the light source 1 are branched and are combined in a light source (light receiver) direction. Optical fiber coupler 2, a phase modulator 3 for phase-modulating the branched light, and a sensing loop 4 for propagating the branched light in both left and right directions and returning it to the optical fiber coupler 2. Each of these optical devices is a pigtail or the like. The optical fiber terminals 5 are connected to each other, and the connecting portion is reinforced by the reinforcing sleeve 6. Specifically, the light source / optical fiber coupler is connected, the optical fiber coupler / phase modulator is connected, and the optical fiber coupler / sensing loop is connected. An optical fiber extra length portion 7 is formed at each connection portion.

In order to store the above optical system in a package or the like, it is necessary to store the optical fiber extra length portion 7.
Conventionally, as shown in FIG. 4, after fixing each optical device on the base 41, each optical fiber extra length portion 7 is grouped into a ring like a figure showing the arithmetic numeral 8 and the It is fixed in a place where it can be fixed.

[0004]

The prior art has the following problems.

There is a need for a space for fixing and storing the extra length of the optical fiber bundled in the shape of 1.8. This hinders miniaturization of the optical rotation angle sensor.

2. The operation of bundling the extra length of the optical fiber into a figure 8 shape is very complicated and requires skill. Further, since it is a complicated work, it takes a long time to carry out the work, which is not suitable for mass production.

3. Since a large number of man-hours are required for storing the surplus portion of the optical fiber and the working time is long, this hinders cost reduction of the optical rotation angle sensor.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and provide a small-sized and inexpensive optical rotation angle sensor which can be easily manufactured.

[0009]

To achieve the above object, the present invention provides an optical rotation angle sensor in which a light source, an optical fiber coupler, a phase modulator and a sensing loop are connected to each other by an optical fiber. An optical fiber between the fiber coupler, the phase modulator and the sensing loop is wound along the sensing loop.

The optical fiber between the optical fiber coupler and the phase modulator and the optical fiber between the optical fiber coupler and the sensing loop may be wound together.

[0011]

Since the sensing loop is formed by winding and bundling the optical fibers, it is easier to wind the optical fibers along with the sensing loop than to form a figure eight shape. That is,
By winding the optical fiber between the optical devices along the sensing loop, the storage becomes easy. Also,
Space is saved because the optical fiber is combined with the sensing loop.

By collectively winding the optical fiber between the optical fiber coupler / phase modulator and the optical fiber between the optical fiber coupler / sensing loop, the optical fiber coupler itself, the light source / the optical fiber coupler / The optical fiber can be wound.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 illustrates the manufacturing process of the optical rotation angle sensor of the present invention.

First, in FIG. 1A, the optical fiber terminals 5 of the light source 1, the optical fiber coupler 2, the phase modulator 3 and the sensing loop 4 are connected to each other, and the connecting portion is reinforced by a reinforcing sleeve 6. Configure the optical system. Each of the connected optical fiber terminals 5 forms an extra length portion 7. The phase modulator 3 and the sensing loop 4 of this optical system are housed in the optical system housing tray 8. Here, the optical system storage tray 8 has an outer cylinder portion 9 that is larger than the outer diameter of the sensing loop 4, and an inner cylinder portion 10 that is smaller than the inner diameter of the sensing loop 4 and larger than the outer diameter of the phase modulator 3. Therefore, the sensing loop 4 is housed between the outer cylinder part 9 and the inner cylinder part 10, and the phase modulator 3 is housed in the inner cylinder part 10.

Next, as shown in FIG. 1 (b), the extra length portion 7a of the optical fiber between the optical fiber coupler and the phase modulator, which is projected from the phase modulator 3 onto the inner cylindrical portion 10, is bent into a circle. After being folded back, the extra length portion 7a is attached to the extra length portion 7b of the optical fiber between the optical fiber coupler and the sensing loop, which is projected from the sensing loop 4, and is aligned.

Then, as shown in FIG. 1C, the optical system storage tray 8 is rotated in the direction of the arrow, that is, in the opposite direction in which the aligned extra lengths 7a and 7b extend. With this rotation, the aligned extra lengths 7a and 7b are collectively wound around the inner cylindrical portion 10, and subsequently, the extra length of the optical fiber between the light source and the optical fiber coupler including the reinforcing sleeve 6 and the optical fiber coupler 2 is included. The part 7c is wound. As a result, the extra length portion 7 of each optical fiber is wound along with the sensing loop 4 and stored in the optical system storage tray 8.

Next, the operation of the embodiment will be described.

Looking at the above manufacturing process, the extra length 7a of the optical fiber between the optical fiber coupler and the phase modulator is compared with the extra length 7a of the optical fiber between the optical fiber coupler and the sensing loop.
Since the optical system storage tray 8 is simply rotated in association with b, the work is very simple. Therefore, neither skill nor long time is required for the work, and the processing cost is reduced, so that the cost reduction is achieved.

In the optical rotation angle sensor manufactured as described above, the extra length portion 7 of each optical fiber is the sensing loop 4.
Since the optical fiber storage tray 8 is wound along with the optical fiber storage tray 8 and is stored in the optical system storage tray 8, there is no need for a separate space for fixing and storing the optical fiber extra length portion 7, and the apparatus is compact. That is, miniaturization of the optical rotation angle sensor is achieved.

In addition, since the optical fiber is not twisted when the extra length portion 7 of the optical fiber is stored, the probability of the optical fiber breaking due to stress is reduced, and the long-term reliability of the optical system of the optical rotation angle sensor is improved. To do.

Next, another embodiment of the present invention will be described.

In the embodiment shown in FIG. 2, the sensing loop 4 is formed by winding an optical fiber around the bobbin 21, and the sensing loop 4 and the bobbin 21 are integrally formed. Therefore, after the light source 1, the optical fiber coupler 2, the phase modulator 3, and the optical devices of the sensing loop 4 are connected to form an optical system, the phase modulator 3 is housed in the hollow portion 22 of the bobbin 21. Next, the extra length portion 7b of the optical fiber between the optical fiber coupler and the sensing loop is bent in a circular shape and folded back, and the extra length portion 7b is placed on the bobbin 21 and the extra length of the optical fiber between the optical fiber coupler and the phase modulator is outputted. Long part 7a
Align with the. Then, the sensing loop 4 is rotated in the direction of the arrow, that is, in the opposite direction in which the aligned extra lengths 7a and 7b extend. In this case, the extra length portions 7a and 7b that are aligned
From the extra length of the optical fiber between the light source and the optical fiber coupler 7
Up to c will be wound around the bobbin 21 of the sensing loop 4.

[0024]

The present invention exhibits the following excellent effects.

(1) There is no need for a separate space for fixing and storing the extra length of the optical fiber, and the optical rotation angle sensor can be miniaturized.

(2) The work of winding the extra length of the optical fiber is very simple, the work requires neither skill nor long time, and the processing cost is reduced. Therefore, the cost of the optical rotation angle sensor is reduced. It

[Brief description of drawings]

FIG. 1 is a manufacturing process diagram of an optical rotation angle sensor showing an embodiment of the present invention.

FIG. 2 is a manufacturing process diagram of an optical rotation angle sensor showing another embodiment of the present invention.

FIG. 3 is a perspective view of an optical system of an optical rotation angle sensor.

FIG. 4 is a manufacturing process diagram of an optical rotation angle sensor showing a conventional example.

[Explanation of symbols]

 1 Light Source 2 Optical Fiber Coupler 3 Phase Modulator 4 Sensing Loop 5 Optical Fiber (Optical Fiber Terminal) 6 Reinforcing Sleeve 7 Optical Fiber (Optical Fiber Extra Length)

Claims (2)

[Claims] 1. An optical rotation angle sensor in which a light source, an optical fiber coupler, a phase modulator and a sensing loop are mutually connected by an optical fiber, wherein the light source, the optical fiber coupler,
An optical rotation angle sensor characterized in that an optical fiber between a phase modulator and a sensing loop is wound along with the sensing loop. 2. The optical rotation angle according to claim 1, wherein the optical fiber between the optical fiber coupler and the phase modulator and the optical fiber between the optical fiber coupler and the sensing loop are wound together. Sensor.