JP3401165B2 - Optical fiber fusion splicer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single-core optical fiber fusion splicer.

[0002]

2. Description of the Related Art In the fusion splicing of single-core optical fibers, the end face spacing of the left and right optical fibers (hereinafter referred to as gap set) and the image processing for measuring the axis deviation are performed. These methods will be described with reference to FIG. FIG. 3A is an explanatory diagram of the image processing circuit. In addition, for convenience of the following description, xyz
Determine the direction of as shown by the arrow. z is the direction of the optical axis 15.

Reference numeral 10 is a light source, 12 is an optical fiber, and 14 is an objective lens. 16 is an image sensor, usually C
A CD camera or the like is used. Image 1 of optical fiber 12
2 ′ is measured by the image sensor 16 and the video signal output from the image sensor 16 is converted into an A / D converter 18
Is digitized, the data is stored in the image memory 20, and the data in the image memory 20 is image-processed by the control board 22. 24 is a monitor.

Conventional image processing is performed only in the y or x (vertical or horizontal) direction as shown in FIG.

The gap set is as follows. As shown in FIG. 6C, the lines 26A and 26B are set to y at positions that are most suitable for the positions of the end faces of the optical fibers for the fusion splicer.
Set to the direction. The optical fiber 12 is moved in the x direction, and when the lines 26A and B recognize the image 12 'of the optical fiber (when the tip of the optical fiber 12 reaches the lines 26A and B), the operation is stopped.

The axis deviation measurement after the gap setting is performed as follows. As shown in FIG. 6D, the lines 28A, 2 are placed at arbitrary positions intersecting the optical fiber image 12 '.
Set 8B in the y direction. Using the lines 28A and 28B, the position of the center 120 of the image 12 'of the optical fiber is calculated, and the axis shift is obtained from this.

[0007]

It is necessary to use a high-performance and expensive device for the image sensor 16, the A / D converter 18, the image memory 20, etc., which results in high cost. If you could use a simpler device,
Cost reduction. As described above, a different line is used for the gap set and the measurement of the axis shift, and thus it is troublesome. Even if the device is the same as the conventional one, if only this point can be solved, the working time can be shortened.

[0008]

The invention according to claim 1 is to solve the above-mentioned problems. To describe with reference to the example of FIG. 1, a line sensor (one-dimensional sensor) 30 is used as an image sensor. In addition, the image processing is performed by placing it obliquely with respect to the real image of the optical fiber 12 in the xy plane where the real image of the optical fiber 12 is formed by the imaging optical system. To do.

The line sensor 30 is a sensor for measuring a one-dimensional intensity distribution of light prepared by arranging a plurality of single photosensors such as photodiodes in a straight line, and has been conventionally used mainly as a photosensor such as a FAX. It is what

If the line sensor 30 is installed obliquely with respect to the real image 12 'of the optical fiber 12 on the image plane of the optical fiber 12, as will be described later, the gap set and the image processing for the axis misalignment calculation are performed simultaneously. can do.

The invention of claim 2 is to solve the above-mentioned problems, and the apparatus itself will be described with reference to the example of FIG.
As in the conventional one (FIG. 3), a two-dimensional sensor is used as the image sensor 16, but the line 32 for image processing is set obliquely with respect to the axis of the image 12 'of the optical fiber. , Image processing.

Only one line 32 is set. By setting this at an angle, it can be used for both gap setting and axis misalignment calculation, as described later.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The example shown in FIG. 1 corresponds to claim 1. The optical fibers 12 are arranged in the x direction, for example, and can be finely moved in the xyz directions as in the conventional case. The line sensor 30, on the image forming plane of the optical fiber 12 (on the xy plane of FIG. 1), as shown in the left side of FIGS. 1B to 1E, shows the axis of the real image 12 ′ of the optical fiber 12. Install diagonally to. The line sensor 30 has a simple structure as compared with the conventional two-dimensional image sensor, and is therefore inexpensive. Further, the A / D converter 18 does not require a conventional high-speed converter for images, and an inexpensive low-speed A / D converter can be used. Also, the image memory 20
A large-capacity RAM as in the past is not necessary, and a small-capacity RAM can be used.

From the line sensor 30, FIG.
As in (d), the luminance data of each point in the longitudinal direction of the line sensor 30 is output. The image memory 20 stores the brightness data of each point when the optical fiber image is not detected by the line sensor at all, that is, the background value.

When the optical fiber image is projected on 30 (see FIG.
(C)), the brightness data changes from the background value. The inner edge portions a and b of the changed portion correspond to the cut portion of the optical fiber, and the outer edge portions c and d correspond to the side surface portion of the optical fiber. The horizontal axis of the brightness data shown on the right side of each of FIGS. 1B to 1D is the dimension in the longitudinal direction of the sensor, but by converting from this value to the actual dimension, from the relationship of the change in the brightness data, It is possible to know the actual positional relationship of the optical fiber.

[Gap set] After the optical fiber 12 is moved in the x direction and the image 12 'thereof is applied to the line sensor 30, the end face distance (gap) of the optical fiber image 12' becomes a predetermined distance. Stop ((c) in the figure). Here, in FIG. 1C, the gap can be obtained from the following equation, where a and b are the positions of the inner edges of the portion where the brightness data is changing from the background value and θ is the angle. it can. Gap = ab * cos θ

[Axis deviation measurement] In FIG. 1 (c) or (d), the positions of the outermost edges of the portion where the luminance data changes from the background value are designated as c and d, and the optical fiber image 12 'and the line are shown. The angle of the sensor 30 is θ. Further, the outer diameter of the image 12 'of the optical fiber 12 is obtained in advance and is set to 2r. The axis shift is obtained from the following formula. Axis deviation = cd * sin θ-2r

Here, it is convenient to know how much the outer diameter of one optical fiber is on the line sensor. As this method, the optical fiber is advanced to intersect the line sensor as shown in FIG. That is,
When only the optical fiber on the left side is advanced in the same figure (c),
Since the interval of ca increases and finally becomes constant, it can be determined that the state of FIG. 1E is reached. Assuming that the side surface of the optical fiber at that time is ca, ca * sin θ = 2r (2r is the outer diameter of the optical fiber), and the outer diameter of the optical fiber on the line sensor can be obtained.

Further, as a result, sin θ = 2r / ca
Therefore, even if the angle θ of the line sensor is not known, the angle θ can be calculated from the outer diameter of the optical fiber and the width of the optical fiber side surface.
Can be asked. From this, the amount of misalignment can be expressed by the following equation. Axis deviation = cd * 2r / ca-2r = (cd / ca-1) 2r

FIG. 2 shows a case corresponding to claim 2. The apparatus itself is the same as that shown in FIG. 3, and a two-dimensional image sensor 16 is used.

Image 32 'of optical fiber 12 through line 32
It is set obliquely with respect to the axis ((b) of the same figure). Other than this, it is the same as the conventional case.

[Gap set] As in the case of FIG. 1 using the line sensor 30, the optical fiber 12 is moved in the x direction (FIG. 2 (b)), the image thereof is applied to the line 32, and then from the above equation. When the obtained gap of the optical fiber image reaches a predetermined gap, the optical fiber image is stopped ((c) in the same figure).

[Measurement of Axis Deviation] This is also the same as the case of the line sensor 30, and the line sensor 30
By using the positions c and d of the side surface of the optical fiber 12 which are concealed, the angle θ between the optical fiber 12 and the line sensor 30, and the outer diameter 2r of the image of the optical fiber 12 which is obtained in advance,
It can be obtained from the above formula.

Here, the angle θ in FIG. 1 or 2 is preferably 45 degrees or more and less than 90 degrees.

[0025]

According to the first aspect of the present invention, the cost can be reduced because an inexpensive parts device can be used. Gap setting and axis misalignment can be performed at the same time, increasing work speed.

In the case of the second aspect of the invention, the gap setting and the axis deviation can be performed at the same time, and the working speed is increased.

[Brief description of drawings]

FIG. 1 is an explanatory view of the present invention according to claim 1.

FIG. 2 is an explanatory view of the present invention according to claim 2.

FIG. 3 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

10 light sources 12 optical fiber 12 'optical fiber image 120 optical fiber center 14 Objective lens 15 Optical axis 16 image sensor 18 A / D converter 20 image memory 22 Control board 24 monitors 26A, B line 28A, B line 30 line sensor 32 lines

Claims (2)

(57) [Claims] 1. In an optical fiber fusion splicer, an optical system forms an image near the tip of an optical fiber, an image near the tip of the optical fiber is taken out as a brightness signal by an optical sensor, and the brightness signal is utilized. In the optical fiber fusion splicer that performs signal processing, as the optical sensor, a one-dimensional sensor is used, and the one-dimensional sensor is in the imaging plane near the tip of the front optical fiber, with respect to the axis of the optical fiber. The optical fiber fusion splicer is characterized in that it is installed diagonally and performs signal processing. 2. In an optical fiber fusion splicer, an optical system forms an image near the tip of an optical fiber, an image near the tip of the optical fiber is taken out as a brightness signal by an optical sensor, and the brightness signal is utilized. In an optical fiber fusion splicer that performs signal processing, a two-dimensional sensor is used as the optical sensor, and the line for signal processing is set obliquely with respect to the axis of the optical fiber, and signal processing is performed. The feature is the optical fiber fusion splicer.