JP2005010027A - Sensing coil structure for optical fiber gyroscope, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve anti-vibration and shock characteristics by fixing an optical fiber with a silicone rubber in a coil bobbin. <P>SOLUTION: The sensing coil for optical fiber gyroscope is constituted so as to fix the optical fiber (8) with silicone rubbers (32, 33, 34, 35) provided in the coil bobbin (30) and to suppress dynamic disturbance over optical fiber (8) by external vibration and shocks. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sensing coil structure for an optical fiber gyro and a method for manufacturing the sensing coil structure, and in particular, by fixing an optical fiber provided in a coil bobbin with silicone rubber, on the sensing coil which is a cause of output instability due to vibration or impact. The present invention relates to a novel improvement for suppressing the mechanical disturbance to optical fibers.
[0002]
[Prior art]
As this type of sensing coil 2 conventionally used, as shown in FIG. 3, an optical fiber 8 wound in a multilayer shape is accommodated on a coil bobbin 30 (see Non-Patent Document 1). It is employed in a fiber gyro (see Patent Document 1).
[0003]
[Non-Patent Document 1]
“Optical Fiber”, page 224, Chapter 7 Optical Fiber Gyro, published by Ohm Company in 1986 [Patent Document 1]
Japanese Patent Laid-Open No. 2000-65584
[Problems to be solved by the invention]
Since the conventional optical fiber sensing coil is configured as described above, the following problems exist.
In other words, the optical fiber is only wound around the coil bobbin, and the optical fiber is exposed, so that it is subjected to mechanical disturbance (moving easily) due to external contact, vibration, shock, and the like. It was easy to improve the reliability of the gyro signal.
That is, an apparent optical path length difference occurs in the light around both the left and right sides of the optical fiber due to external stimuli.
This phenomenon appears as an error in the gyro signal because it cannot be distinguished from the difference between the optical path lengths of the left and right light beams that occur when the optical fiber gyroscope should detect rotation.
[0005]
The present invention has been made in order to solve the above-described problems, and in particular, by fixing an optical fiber provided in a coil bobbin with silicone rubber, it is a cause of output instability due to vibration or impact. It is an object of the present invention to provide a sensing coil structure for an optical fiber gyro and a method for manufacturing the same that suppresses mechanical disturbance to the optical fiber on the sensing coil.
[0006]
[Means for Solving the Problems]
The sensing coil structure for an optical fiber gyro according to the present invention has a configuration in which an optical fiber is fixed by silicone rubber provided in a coil bobbin, and the optical fiber is superposed in a plurality of layers along the depth direction in the coil bobbin. The silicone rubber is interposed between the layers, and the method for manufacturing the sensing coil for an optical fiber gyroscope according to the present invention cures after coating the bottom of the coil bobbin with liquid silicone rubber. A first-layer silicone rubber is formed, and a first-layer optical fiber is wound around the first-layer silicone rubber. A liquid silicone rubber is coated on the first-layer optical fiber and then cured to form two layers. Forming a second silicone rubber, winding a second optical fiber on the second silicone rubber, A liquid silicone rubber is coated on the layer optical fiber and then cured to form a third layer silicone rubber, and the silicone rubber and the optical fiber are formed into a required n layer, and the optical fiber comprises: It is a method embedded in the silicone rubber.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of a sensing coil structure for an optical fiber gyro and its manufacturing method according to the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected and demonstrated to a part the same as that of a prior art example, or an equivalent part.
First, an optical fiber gyro to which the sensing coil structure for an optical fiber gyro according to the present invention is applied will be described.
FIG. 2 shows an optical fiber gyroscope 20 of a phase modulation method (other than this method is also possible).
That is, what is indicated by reference numeral 1 in FIG. 1 is an optical system having a ring-shaped sensing coil 2 formed of an optical fiber, and this sensing coil 2 passes through a first coupler 3, a polarizer 4, and a second coupler 5. The light source module 6 and the detector 7 are connected by an optical fiber 8.
Between the sensing coil 2 and the first coupler 3, a phase modulator 9 made of a known piezo element (PZT) is provided in contact with the optical fiber 8 and located in the vicinity of the sensing coil 2. . By driving the phase modulator 9 with an alternating current signal having a predetermined frequency, the phase difference of the light generated by the angular velocity is made to interfere to obtain the gyro output 18a by the well-known optical sagnac effect.
[0008]
An optical fiber gyro drive circuit 10 that is an electrical system is connected to the optical system 1, and an output 7 a of the detector 7 is photoelectrically converted and input to an input amplifier 11 of the optical fiber gyro drive circuit 10. . A light source driving circuit 12 connected to the output side of the input amplifier 11 is connected to the light source module 6 via a light source driver 13, and laser light is incident on the optical fiber 8 from the light source module 6.
A modulation control circuit 14 and a lock-in amplifier 17 are connected to the output side of the input amplifier 11, and an oscillation circuit 15 and a driver 16 are connected to the modulation control circuit 14, and the output of the driver 16 is the phase modulator. 9 is input. The output of the oscillation circuit 15 is input to the driver 16 and input to the lock-in amplifier 17, and a gyro output 19 is obtained from the lock-in amplifier 17 via the output amplifier 18.
Accordingly, the optical fiber gyro 20 is configured by the optical system 1 and the optical fiber gyro drive circuit 10 described above.
[0009]
The sensing coil 2 is manufactured through steps (A) to (F) shown in FIG. 1. In (A), one layer is formed after coating liquid silicone rubber on the bottom 31 which is the surface of the coil bobbin 30. In (B), the first silicone rubber 32 is formed, and the first-layer optical fiber 8a is wound around the first-layer silicone rubber 32. In (C), the liquid silicone is formed on the first-layer optical fiber 8a. After the silicone rubber is coated, it is cured to form a second layer silicone rubber 33, and the first layer optical fiber 8 a is fixed by the second layer silicone rubber 33.
[0010]
Next, in (D), the second-layer optical fiber 8b is wound on the second-layer silicone rubber 33, and in (E), liquid silicone rubber is coated on the second-layer optical fiber 8b. Then, it is cured to form a third-layer silicone rubber 34, and the second-layer optical fiber 8 b is fixed by the third-layer silicone rubber 34.
[0011]
The above steps (A) to (E) are performed according to the number of layers of the optical fiber 8, and in the n-th (N) step, the n-th layer optical fiber 8 n is fixed by the n + 1-th layer silicone rubber 35 to complete. In the completed state, the entire optical fiber 8 is embedded and fixed in silicone rubber.
[0012]
【The invention's effect】
Since the sensing coil structure for an optical fiber gyro and the manufacturing method thereof according to the present invention are configured as described above, the following effects can be obtained.
That is, the optical fiber composed of each layer can be fixedly held in the coil bobbin using silicone rubber, and the mechanical fiber to the optical fiber generated when a mechanical stimulus such as vibration or impact is applied to the optical fiber gyroscope. Disturbances can be erased.
Accordingly, unnecessary errors due to vibration and impact of the optical fiber gyroscope can be eliminated, and improvement in accuracy and reliability can be obtained.
[Brief description of the drawings]
FIG. 1 is a process diagram showing a method of manufacturing a sensing coil structure for an optical fiber gyro according to the present invention.
FIG. 2 is a block diagram showing an optical fiber gyro using the sensing coil of FIG.
FIG. 3 is a cross-sectional view showing a conventional sensing coil.
[Explanation of symbols]
2 sensing coil 8 optical fiber 8a first layer optical fiber 8b second layer optical fiber 8n n layer optical fiber 20 optical fiber gyro 30 coil bobbin 31 bottom 32 first layer silicone rubber 33 second layer silicone rubber 34 third layer silicone rubber 35 n layer Eye silicone rubber

Claims (4)

A sensing coil structure for an optical fiber gyro, wherein the optical fiber (8) is fixed by silicone rubber (32, 33, 34, 35) provided in the coil bobbin (30). A plurality of layers of the optical fiber (8) are arranged along the depth direction in the coil bobbin (30), and the silicone rubber (32, 33, 34, 35) is interposed between the layers. The sensing coil structure for an optical fiber gyroscope according to claim 1, wherein A liquid silicone rubber is coated on the bottom (31) of the coil bobbin (30) and then cured to form a first layer silicone rubber (32).
The first layer optical fiber (8a) is wound around the first layer silicone rubber (32),
A liquid silicone rubber is coated on the first layer optical fiber (8a) and then cured to form a second layer silicone rubber (33).
A second-layer optical fiber (8b) is wound around the second-layer silicone rubber (33).
A liquid silicone rubber is coated on the second layer optical fiber (8b) and then cured to form a third layer silicone rubber (34).
A method for producing a sensing coil for an optical fiber gyro, wherein the silicone rubber (32, 33, 34, 35) and an optical fiber (8) are formed in a required n layer. The method of manufacturing a sensing coil for an optical fiber gyro according to claim 3, wherein the optical fiber (8) is embedded in the silicone rubber (32, 33, 34, 35).

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