JPH07209002A - Manufacture of sensing coil for gyroscope - Google Patents

Abstract

PURPOSE:To provide a manufacturing method for sensing coil for gyroscope which is stable in temperature characteristics, etc. CONSTITUTION:An optical fiber 2 and a bobbin 1 are prepared, one or two layers of the optical fiber are wound adjacently around the bobbin 1 from the middle part to one end of the fiber 2, and further one or two layers of the fiber are wound adjacently on it from the middle part to the other end of the fiber 2. The same winding procedure is repeated so as to form a sensing coil for gyroscope. The optical fiber 2 is a quartz-based fiber which is coated with a hard resin with a Young's modulus of 40kg/mm<2> or more. Also the tension to wound the fiber 2 around the bobbin l is held at 40 gram or lower.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a sensing coil for a gyroscope which has stable temperature characteristics and the like.

[0002]

2. Description of the Related Art In order to detect the position or attitude of a moving body such as an aircraft, a ship, an automobile, etc., a gyroscope is constructed by using an optical fiber coil, and a phase change of light generated when the coil is subjected to a rotating action is detected. There is a measuring system. By the way, the phase difference to be detected is 10 ⁻³ to 10 ⁻⁷ r
It is necessary to handle very small areas such as ad. Therefore, in order to improve the performance of the gyroscope, the factors of each component and the detection method were examined, and the sensing coil was set under the conditions such as temperature and pressure generated in the inner layer and the outer layer wound on the bobbin. Symmetrical windings have been proposed for uniformity. That is, as shown in FIG.
And a bobbin 1 are prepared, and one or two layers are wound adjacently on the bobbin 1 from the middle part of the fiber 2 toward one end, and the bobbin 1 is wound on the bobbin 1 from the middle part to the other end. Is a method of manufacturing a sensing coil for a gyroscope, which is formed by winding one layer or two layers adjacent to each other, and then repeatedly winding the same.

[0003]

In the coil using such a symmetrical winding, the fiber on the A end side and the fiber on the B end side are alternately wound, so that the fiber 2 is inserted from the A end or the B end side. When viewed, the temperature or pressure conditions are made uniform. However, there has been a problem that the transmission loss of the fiber or the crosstalk characteristic of the polarization plane changes depending on the temperature condition and directly affects the performance of the gyroscope. Therefore, an object of the present invention is to provide a method for manufacturing a sensing coil for a gyroscope, which solves the above problems.

[0004]

A method of manufacturing a sensing coil for a gyroscope according to the present invention prepares an optical fiber and a bobbin, and places one on the bobbin from an intermediate portion of the fiber toward one end. Manufacture of a sensing coil for a gyroscope, which is formed by winding one layer or two layers adjacently, winding one layer or two layers adjacently from the middle portion of the fiber toward the other end, and repeating the same in the following manner. The optical fiber is a silica-based fiber coated with a hard resin having a Young's modulus of 40 kg / mm ² or more, and is wound with a tension of 40 gr or less, and the optical fiber is a single mode fiber. Alternatively, it is preferably a polarization-maintaining fiber.

[0005]

According to the above construction, since the method of manufacturing the sensing coil according to the present invention employs the symmetrical winding, it is almost the same when the optical signal is incident from one side and when the optical signal is incident from the other side. The same transmission characteristics are obtained. Further, since the silica glass fiber is coated with the hard resin, the structure is stable even when wound around the bobbin, and the reliability is improved. Further, since the tension around the bobbin is kept small, the force acting between the fibers becomes small, and the initial fiber characteristics can be maintained even when wound around the bobbin.

[0006]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In the description of the drawings, the same elements will be denoted by the same reference symbols, without redundant description. FIG. 1 is a schematic diagram showing a configuration relating to a manufacturing method of the present embodiment, FIG. 2 is a sectional view of a bobbin in which an optical fiber is symmetrically wound, and FIG. 3 is a diagram showing a structure of an optical fiber applied to the present invention. is there.

The bobbin 1 constituting the support frame of the sensor is attached to the winding device 5, and the optical fiber 2 wound around the two reels 3A and 3B is wound around the bobbin 1 from the supply stand 4. The optical fiber 2 is wound around the reels 3A and 3B from both ends thereof, the reel 3A is attached to the supply stand 4, and when the fiber 2 is being supplied to the bobbin 1, the other reel 3B rotates with the bobbin 1. So that it is fixed.

The bobbin 1 is made of a metal material such as Invar having an extremely small coefficient of thermal expansion, and the body surface of the bobbin and the inner side of the collar are precisely finished to prevent the deterioration of the fiber characteristics due to the unevenness of the surface.

FIG. 3 (a) shows a polarization-maintaining fiber in which a resin coating layer 12 is provided on a silica fiber consisting of a core 10, a clad 11 and a stress applying portion 13, and FIG. 3 (b) shows a core. A single-mode fiber in which a resin coating layer 12 is provided on a silica-based fiber composed of 10 and a clad 11 is shown. Conventionally, the resin used for the coating layer 12 is a soft silicone resin in order to relieve the processing strain, but in the present invention, the Young's modulus is at least 40 kg / mm ² or more like the urethane acrylate UV curable resin. Apply hard resin. This is because it is possible to withstand the compressive force even after being wound on the bobbin and maintain the fiber characteristics.

An example of symmetrical winding using the device shown in FIG. 1 will be described. FIG. 3A shows the two reels 3A and 3B.
The polarization-maintaining fiber 2 shown in (1) is wound from both ends toward the center. First, the reel 3A is attached to the supply stand 4, and is wound around the bobbin 1 in close contact with the bobbin 1 by the winding device 5 to make one reciprocation.
Wrap layer (1). At this time, reel 3B is bobbin 1
It is fixed so that it will rotate together with it. Then reel 3
B is attached to the supply stand 4, the reel 3A is fixed so as to rotate together with the bobbin 1, and the second layer (2) is wound. Thereafter, in the same manner, the n-th layer (n) was wound to form a polarization-maintaining fiber coil having a total length of 500 m.
(In addition to this, the symmetrically wound product is further wound in one row at the beginning and end of the bobbin.) At this time, the supply tension of the fiber 2 was kept at 40 gr.

When the crosstalk of the above coil was measured at a wavelength of 0.85 μm under the temperature condition of −40 ° C. to + 80 ° C., it was about −30 dB as compared with −33 dB before being wound on the bobbin. It was Furthermore, tension is 30g
When it was wound with r, a slightly improved result was obtained. On the other hand, when the tension was increased to 50 gr, the crosstalk decreased to about -25 dB. In addition, the tension of the polarization-maintaining fiber coated with silicone resin is 50 gr.
When wound around, crosstalk decreased to -20 dB and reproducibility was poor.

The single mode fiber 5 shown in FIG.
00m was wound with a tension of 40 gr, and bobbins were exchanged for each layer, and the target winding was performed. When the transmission loss was measured at a wavelength of 0.85 μm, it was about 1.25 dB under the temperature condition of −40 ° C. to + 80 ° C., which was only a slight increase compared with 1.1 dB before winding the bobbin. On the other hand, tension is 50
When it was raised to gr, it rapidly increased to 1.8 dB.

[0013]

As described above, since the method of manufacturing the sensing coil according to the present invention employs the symmetrical winding, the case where the optical signal is incident from one side and the case where the optical signal is incident from the other side is adopted. Almost the same transmission characteristics are obtained. Also,
Since the quartz glass fiber is coated with a hard resin, the structure is stable even when wound around a bobbin, and the reliability is improved. Further, since the tension around the bobbin is kept small, the force acting between the fibers becomes small, and the initial fiber characteristics can be maintained even when wound around the bobbin.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration relating to a manufacturing method of this embodiment.

FIG. 2 is a sectional view of a symmetrically wound bobbin.

FIG. 3 is a diagram showing a structure of an optical fiber applied to the present invention.

[Explanation of symbols]

 1: bobbin 2, 2 ', 2 ": optical fiber 3: reel 4: supply stand 5: winding device 10: core 11: clad 12: coating layer 13: stress applying part

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location G02B 6/44 321

Claims (2)

[Claims] 1. An optical fiber and a bobbin are prepared, and one or two layers are wound adjacently on the bobbin from the middle part of the fiber toward one end, and then, from the middle part of the fiber. 1 layer or 2 towards the other end
A method of manufacturing a sensing coil for a gyroscope, which is formed by winding layers adjacent to each other, and then repeatedly winding the same, wherein the optical fiber is a silica-based fiber coated with a hard resin having a Young's modulus of 40 kg / mm ² or more. And 40g
A method for manufacturing a sensing coil for a gyroscope, which comprises winding with a tension of r or less. 2. The method for manufacturing a sensing coil for a gyroscope according to claim 1, wherein the optical fiber is a single-mode fiber or a polarization-maintaining fiber.