WO2024127602A1

WO2024127602A1 - Fusion splicing device and fusion splicing method

Info

Publication number: WO2024127602A1
Application number: PCT/JP2022/046279
Authority: WO
Inventors: 貴洋諏訪; 優太漁野
Original assignee: 住友電工オプティフロンティア株式会社
Priority date: 2022-12-15
Filing date: 2022-12-15
Publication date: 2024-06-20
Also published as: WO2024128236A1

Abstract

The fusion splicing device according to an embodiment comprises: a stage on which an optical fiber is placed; a drive unit which moves the stage; a microscope which captures the optical fiber, and outputs the brightness of an image obtained through capturing for each pixel; and a position recognition unit which recognizes the position of a surface of the optical fiber from the brightness of each pixel output by the microscope. The drive unit sequentially moves the optical fiber by a constant distance. The constant distance is shorter than the pixel size of a pixel. The microscope captures the optical fiber every time the drive unit moves the optical fiber by the constant distance. The position recognition unit recognizes the position of a surface of the optical fiber moved by the drive unit from a plurality of values of brightness of a plurality of images obtained by the microscope.

Description

Fusion splicer and fusion splicing method

This disclosure relates to a fusion splicer and a fusion splicing method.

Patent Document 1 describes an optical fiber fusion splicer. The optical fiber fusion splicer connects a pair of optical fibers to each other while melting the optical fibers. The optical fiber fusion splicer has a fiber feed section that holds multiple optical fibers. The fiber feed section moves the multiple optical fibers along the longitudinal direction of the optical fibers. The optical fiber fusion splicer includes a camera that continuously captures images of the moving optical fibers, and a control board. The control board has an image data processing section that processes image data captured by the camera to recognize the movement of the optical fiber. The image data processing section performs image data processing to recognize the operation of the optical fiber from the differences between the multiple image data.

Patent Document 2 describes a method and device for fusion splicing optical fibers. The splicing device includes a mounting section on which the optical fiber is placed, a holder that holds multiple optical fibers, and a TV camera that photographs the multiple optical fibers. The TV camera is provided to measure the axial misalignment of the optical fibers.

Patent document 3 describes an optical fiber fusion splicing device. The fusion splicing device includes a positioning table having a V-groove into which the optical fiber is inserted, an imaging camera that images the optical fiber from above the positioning table, and a fine alignment mechanism that aligns the optical fiber. The imaging camera outputs the image of the optical fiber obtained by imaging as an imaging signal to an image processing device. The image processing device includes a calculation unit that performs calculations for aligning the optical fiber based on the imaging signal to generate a processing signal, and a control unit that controls the operation of the fine alignment mechanism in response to the processing signal from the calculation unit.

JP 2005-189770 A Japanese Patent Application Laid-Open No. 10-239553 Japanese Patent Application Laid-Open No. 5-164934

The fusion splicer according to the present disclosure comprises a stage on which the optical fiber is placed, a drive unit for moving the stage, a microscope for capturing an image of the optical fiber and outputting the brightness of the captured image for each pixel, and a position recognition unit for recognizing the position of the surface of the optical fiber from the brightness of each pixel output by the microscope. The drive unit moves the optical fiber at fixed distances. The fixed distance is shorter than the pixel size of the pixels. The microscope captures an image of the optical fiber each time the drive unit moves the optical fiber a fixed distance. The position recognition unit recognizes the position of the surface of the optical fiber moved by the drive unit from the multiple brightnesses of the multiple images captured by the microscope.

FIG. 1 is a perspective view showing a fusion splicer according to an embodiment. FIG. 2 is a perspective view showing the internal structure of the fusion splicer according to the embodiment. FIG. 3 is a perspective view showing a fusion splicer base and optical fibers according to an embodiment. FIG. 4 is a block diagram showing the functional configuration of the fusion splicer according to the embodiment. FIG. 5 is a schematic diagram showing an image of an optical fiber captured by a microscope. FIG. 6 is a diagram showing the position of the optical fiber in an image obtained by imaging. FIG. 7 is a diagram showing an image of the optical fiber obtained by imaging. FIG. 8 is a flow chart illustrating example steps of a fusion splicing method according to an embodiment. FIG. 9 is a diagram for explaining the procedure of moving the optical fiber, capturing an image of the optical fiber, and recognizing the position of the optical fiber. FIG. 10 is a diagram for explaining a procedure for moving an optical fiber, capturing an image of the optical fiber, and recognizing the position of the optical fiber according to the modified example. FIG. 11 is a diagram for explaining a procedure for moving an optical fiber, capturing an image of the optical fiber, and recognizing the position of the optical fiber according to a modified example different from that shown in FIG. FIG. 12 is a diagram for explaining the procedure of moving the optical fiber, capturing an image of the optical fiber, and recognizing the position of the optical fiber according to a modified example different from those in FIG. 9 and FIG.

However, if the resolution of the microscope that images the optical fiber is low, the image may become coarse. In particular, in a fusion splicer that fusion-splices multi-core optical fibers, the magnification of the microscope may be low because multiple optical fibers are imaged. In such cases, the resolution of the microscope is often low. Therefore, since the image of the optical fiber is coarse, the position of the surface of the optical fiber may not be recognized accurately. For example, if the position of the end face of the optical fiber to be fusion-spliced cannot be recognized accurately, connection loss of the optical fiber may occur.

The present disclosure aims to provide a fusion splicer that can accurately recognize the position of the surface of an optical fiber.

[Description of the embodiments of the present disclosure]
First, the embodiments of the present disclosure will be listed and described. A fusion splicer according to one embodiment includes (1) a stage on which an optical fiber is placed, a drive unit for moving the stage, a microscope for capturing an image of the optical fiber and outputting the brightness of the captured image for each pixel, and a position recognition unit for recognizing the position of the surface of the optical fiber from the brightness of each pixel output by the microscope. The drive unit moves the optical fiber at fixed distances. The fixed distance is shorter than the pixel size of the pixel. The microscope captures an image of the optical fiber every time the drive unit moves the optical fiber by the fixed distance. The position recognition unit recognizes the position of the surface of the optical fiber moved by the drive unit from multiple brightnesses of multiple images captured by the microscope.

In this fusion splicer, the stage on which the optical fiber is placed is moved by the drive unit, and the microscope captures an image of the moving optical fiber surface. The microscope outputs the brightness of the image obtained by capturing an image for each pixel. The position recognition unit recognizes the position of the optical fiber from the brightness of each pixel of the image. The drive unit moves the optical fiber at fixed distances shorter than the pixel size, and the microscope captures an image of the optical fiber each time the optical fiber moves a fixed distance. The position recognition unit then recognizes the position of the moved optical fiber surface from the multiple brightnesses of the multiple images. Therefore, an image is obtained each time the optical fiber moves a fixed distance shorter than the pixel size, and the position of the optical fiber surface is recognized from the multiple brightnesses of the multiple images, so that the position of the optical fiber surface can be recognized with high accuracy. Even if the resolution of the microscope is low and the pixels of the image are coarse, by capturing an image each time it moves a fixed distance shorter than the pixel size, the position of the optical fiber surface can be accurately recognized from the multiple images obtained as a result of the capturing.

(2) In the above (1), the position recognition unit may recognize, as a reference position, the position of the optical fiber surface in an image in which, among the multiple images, the position of the surface is closest to one side of a pixel. In this case, the position recognition unit can more accurately recognize the position of the optical fiber surface after the movement by recognizing how many times the drive unit has moved the optical fiber a certain distance from the reference position.

(3) In (2) above, the position recognition unit may recognize as the reference position the position of the optical fiber in an image among the multiple images in which the luminance difference between two pixels aligned along the movement direction of the optical fiber is maximum. In this case, the position recognition unit can easily recognize the reference position from the luminance difference between two pixels aligned along the movement direction.

(4) In the above (2) or (3), the position recognition unit may store the movement distance of the optical fiber from a reference position, and may recognize the position of the surface by adding the movement distance of the optical fiber from the reference position to the reference position.

(5) In (4) above, the position recognition unit may store the number of times the optical fiber has moved a fixed distance from the reference position, and may recognize the position of the surface by adding the product of the number of times the optical fiber has moved from the reference position and the fixed distance as the moving distance to the reference position.

(6) In any of (1) to (5) above, the driving unit may move the optical fiber along the longitudinal direction of the optical fiber.

(7) In any of (1) to (5) above, the driving unit may move the optical fiber in a direction perpendicular to the longitudinal direction of the optical fiber.

(8) In any of (1) to (7) above, the aforementioned fixed distance may be equal to or less than half the pixel size. In this case, an image of the optical fiber is captured every time the optical fiber moves a fixed distance that is equal to or less than half the pixel size, so that the position of the optical fiber surface can be recognized more accurately from multiple images.

(9) In any of (1) to (8) above, the surface may be an end face of the optical fiber located at one end in the longitudinal direction of the optical fiber. In this case, the position of the end face of the optical fiber can be accurately recognized.

(10) In any of (1) to (8) above, the surface may be a side surface of the optical fiber extending along the longitudinal direction of the optical fiber. In this case, the position of the side surface of the optical fiber can be accurately recognized.

(11) In any of (1) to (10) above, the microscope may have an image sensor that captures an image of the optical fiber, and an image processor that processes the image of the optical fiber captured by the image sensor. The image processor may output the brightness of the image for each pixel.

(12) In (11) above, the image processing unit may calculate the luminance difference between two pixels aligned along the moving direction of the optical fiber, and the position recognition unit may store the luminance difference calculated by the image processing unit.

(13) In any of (1) to (12) above, the fusion splicer may be a multi-fiber fusion splicer that fusion-splices multiple optical fibers together.

(14) In any of (1) to (13) above, the position recognition unit may store an image captured by the microscope and recognize the position of the optical fiber from the brightness of each output pixel.

(15) In any of (1) to (14) above, the position recognition unit may recognize, among the multiple pixels, the position of a pixel that is between the pixel with the highest brightness and the pixel with the lowest brightness as the position of the surface.

A fusion splicing method according to one embodiment (16) includes the steps of: moving a stage on which an optical fiber is placed; capturing an image of the optical fiber; outputting the brightness of the image obtained by the capturing step for each pixel; and recognizing the position of the surface of the optical fiber from the brightness of each pixel. In the moving step, the optical fiber is moved a fixed distance at a time. The fixed distance is shorter than the pixel size of the pixels. In the capturing step, an image of the optical fiber is captured every time the optical fiber moves a fixed distance. In the position recognition step, the position of the surface of the moved optical fiber is recognized from multiple brightnesses of multiple images.

In this fusion splicing method, as in the fusion splicer described above, the surface of the moving optical fiber is imaged, and the brightness of the image obtained by imaging is output for each pixel. In the position recognition process, the position of the optical fiber is recognized from the brightness of each pixel of the image. In this position recognition, the position of the surface of the moving optical fiber is recognized from the multiple brightnesses of multiple images. Therefore, as in the fusion splicer described above, an image is obtained each time the optical fiber moves a fixed distance shorter than the pixel size, and the position of the surface of the optical fiber is recognized from the multiple brightnesses of the multiple images, so that the position of the surface of the optical fiber can be recognized with high accuracy. As a result, even if the resolution of the microscope is low and the pixels of the image are coarse, by capturing an image every time it moves a fixed distance, the position of the surface of the optical fiber can be accurately recognized from the multiple images obtained as a result of the imaging.

[Details of the embodiment of the present invention]
A specific example of a fusion splicer and a fusion splicing method according to an embodiment of the present disclosure will be described. In the description of the drawings, the same or corresponding elements are given the same reference numerals, and duplicated descriptions will be omitted as appropriate. The drawings may be partially simplified or exaggerated for ease of understanding, and the dimensional ratios and the like are not limited to those shown in the drawings.

FIG. 1 is a perspective view showing a specific example of a fusion splicer 1. The fusion splicer 1 has a box-shaped housing 2 and a windshield cover 6 located on top of the housing 2. FIG. 2 is a perspective view showing the windshield cover 6 in an open state. As shown in FIGS. 1 and 2, the fusion splicer 1 has a fusion splicing section 3 that fuses optical fibers together. The fusion splicer 1 has a monitor 5 that displays the state of the fusion splicing of the optical fibers together, as imaged by a microscope 15 (see FIG. 4), which will be described later. In addition, the fusion splicer 1 has a heater 4 that heats and shrinks a fiber reinforcement sleeve that is placed over the connection of the optical fibers fused in the fusion splicing section 3, a power switch 7 that switches the power of the fusion splicer 1 on and off, and a connection start switch 8 for fusion splicing the optical fibers.

The fusion splicing unit 3 includes, for example, a pair of fiber positioning units 3a, a pair of electrode rods 3b for discharging, and a pair of fiber holders 3c. Each of the optical fibers to be fused is held in the fiber holder 3c. The fiber positioning unit 3a is disposed between the pair of fiber holders 3c and positions the end face of the optical fiber fixed to each fiber holder 3c. The "end face" refers to the face of the optical fiber located at one end in the longitudinal direction of the optical fiber. The pair of electrode rods 3b are disposed between the pair of fiber positioning units 3a. The electrode rods 3b are electrodes for fusing the end faces of the optical fibers together by arc discharge. The electrode rods 3b and the fiber holders 3c are aligned along the Z-axis direction. The Z-axis direction is the direction in which each of the multiple optical fibers to be fusion spliced extends.

The windshield cover 6 is connected to the housing 2 so as to cover the fusion splicing section 3 in an openable and closable manner. The power switch 7 is a push button for switching the power of the fusion splicing machine 1 on and off in response to the operation of the user of the fusion splicing machine 1. The connection start switch 8 is a push button for starting the operation of fusing optical fibers together in response to the operation of the user.

FIG. 3 is a perspective view showing a schematic diagram of the detailed structure of the fusion splicing section 3. As shown in FIG. 3, the fusion splicer 1 has a stage 11 on which multiple optical fibers F to be fusion spliced are placed. In this embodiment, the fusion splicer 1 is a multi-core fusion machine that fusion splices multiple optical fibers F together. The fusion splicer 1 has a pair of stages 11 aligned along the Z-axis direction.

The base 11 has a main surface 12 on which multiple optical fibers F are placed, and multiple V-grooves 13 that are recessed in the main surface 12 and into which the optical fibers F are inserted. In the base 11, the multiple V-grooves 13 are aligned along the X-axis direction that intersects with the Z-axis direction. The X-axis direction is an in-plane direction of the main surface 12, and is, for example, a direction perpendicular to the Z-axis direction. Each V-groove 13 is recessed from the main surface 12 in the Y-axis direction that intersects with both the X-axis direction and the Z-axis direction. The Y-axis direction is, for example, a direction perpendicular to both the X-axis direction and the Z-axis direction. The multiple optical fibers F inserted into each V-groove 13 are aligned along the X-axis direction on the main surface 12. A pair of electrode rods 3b are arranged on both sides of the multiple optical fibers F in the X-axis direction.

The fusion splicer 1 has a drive unit 14 that moves the table 11. The drive unit 14, for example, moves each of the pair of tables 11. The drive unit 14, for example, moves the optical fiber F placed on the table 11 along the Z-axis direction. In this case, the Z-axis direction is the movement direction of the optical fiber. The drive unit 14 adjusts the position of the end face F1 of the optical fiber F by moving the table 11 along the Z-axis direction. The drive unit 14 adjusts the position of the optical fiber F in the Z-axis direction so that the distance from the virtual straight line L connecting the pair of electrode rods 3b to the end face F1 is a predetermined distance. The drive unit 14 makes this adjustment to the pair of optical fibers F aligned along the Z-axis direction, so that the optical fibers F can be appropriately fusion spliced by the pair of electrode rods 3b.

The driving unit 14 is, for example, a stepping motor. In this case, the driving unit 14 drives according to the applied pulse voltage. The stage 11 moves along the Z-axis direction by driving the driving unit 14. For example, the driving unit 14 finely moves the optical fiber F placed on the stage 11 to finely adjust the position of the end face F1 of the optical fiber F. "Fine movement" refers to moving a distance shorter than the pixel size of an image captured by the microscope 15 described later. Also, the "pixel size" referred to here refers to the length measured along the moving direction of the optical fiber F. The driving unit 14 finely moves the optical fiber F by a fixed distance at a time. The "fixed distance" refers to, for example, the amount of movement of the optical fiber F per pulse by the driving unit 14. For example, the "fixed distance" is 1 μm or more and less than 10 μm. As an example, the "fixed distance" is 2 μm.

Figure 4 is a block diagram showing the functions of the microscope 15 and the position recognition unit 20. Figure 5 is a diagram showing an image captured by the microscope 15. As shown in Figures 4 and 5, the fusion splicer 1 has a microscope 15 that captures an image of an optical fiber F, and a position recognition unit 20 that recognizes the position of the end face F1 of the optical fiber F from the image of the optical fiber F captured by the microscope 15. The microscope 15 captures images of multiple optical fibers F placed on each of a pair of stages 11. The microscope 15 is, for example, a CCD camera (Charge-Coupled Device Camera) or a CMOS camera (Complementary Metal Oxide Semiconductor Camera).

The microscope 15 has, for example, an image sensor 16 and an image processor 17. The image sensor 16 captures an image of the optical fiber F, and the image processor 17 processes the image of the optical fiber F captured by the image sensor 16. The image processor 17 outputs the brightness of the image for each pixel. The pixel size of the image captured by the image sensor 16 is larger than the fixed distance described above. For example, the pixel size of the image captured by the image sensor 16 is more than twice the fixed distance described above. This pixel size is set to a large value because the fusion splicer 1 is a multi-fiber fusion machine and needs to capture images of multiple optical fibers F lined up along the X-axis direction. As an example, the pixel size is 10 μm.

The position recognition unit 20 may be, for example, a CPU (Central Processing Unit) configured with one or more integrated circuits (ICs). For example, the position recognition unit 20 stores an image captured by the imaging element 16. The position recognition unit 20 recognizes the position of the optical fiber F from the brightness of each pixel output by the image processing unit 17.

FIG. 6 is a diagram showing the end face F1 of the optical fiber F in a captured image. FIG. 7 is a diagram showing an image of the captured optical fiber F. As shown in FIGS. 6 and 7, when the pixel size of the image is large, the actual position P of the end face F1 in the Z-axis direction may become blurred, and the position recognition unit 20 may not be able to recognize the exact position of the end face F1. More specifically, the position recognition unit 20 may be able to recognize that the end face F1 is located in a blurred pixel X portion in the image, but may not be able to recognize where within pixel X the end face F1 is located.

Meanwhile, the drive unit 14 fine-tunes the position of the end face F1 in the Z-axis direction in order to properly fusion splice the optical fiber F. However, if the position recognition unit 20 cannot recognize the exact position of the end face F1 as described above, then the end face F1 may not be in an appropriate position, and it may not be possible to properly fusion splice. In this case, there is a possibility that poor connection or the like may occur. In contrast, in the fusion splicer 1 and fusion splicing method according to this embodiment, the position recognition unit 20 can recognize the exact position of the end face F1. An example of the steps of the fusion splicing method is described below.

FIG. 8 is a flowchart showing an example of the steps of the fusion splicing method according to this embodiment. FIG. 9 shows an image captured by the microscope 15. In this fusion splicing method, a pair of optical fibers F to be fusion spliced are placed on each of a pair of bases 11 so that a pair of end faces F1 face each other (step of placing optical fibers, step S1). At this time, the optical fibers F are inserted into each V-groove 13 of the bases 11, and the optical fibers F are placed so that multiple optical fibers F are lined up along the X-axis direction on each base 11.

Next, the microscope 15 images the optical fiber F (step of imaging an optical fiber, step S2). At this time, an image M1 of the optical fiber F is obtained by the imaging element 16. Then, the image processing unit 17 outputs the luminance of the image M1 for each pixel X1. For example, the luminance of each pixel X1 of the image M1 output by the image processing unit 17 is output to the position recognition unit 20. In this case, the position recognition unit 20 recognizes the position of the end face F1 from the luminance of each pixel X1 of the image M1. As a specific example, the position recognition unit 20 recognizes the position of pixel X13, which is between pixel X11 with the highest luminance and pixel X12 with the lowest luminance among the multiple pixels X1, as the position of the end face F1.

Next, the driving unit 14 moves the stage 11 on which the optical fiber F is placed (stage moving step). For example, the driving unit 14 fixes one of the two stages 11 and moves the unfixed stage 11 along the Z-axis direction. At this time, the driving unit 14 finely moves the optical fiber F to move it a certain distance in the Z-axis direction (step S3). After that, the microscope 15 images the optical fiber F (optical fiber imaging step, step S4). At this time, an image M2 of the optical fiber F is obtained by the imaging element 16.

The image processing unit 17 outputs the luminance of image M2 for each pixel X1 and calculates the luminance difference. For example, the position recognition unit 20 stores the luminance difference calculated by the image processing unit 17. The image processing unit 17 calculates, for example, the luminance difference between two pixels X1 aligned along the Z-axis direction (step S5, process of calculating the luminance difference). For example, the image processing unit 17 calculates the difference between the luminance of pixel X11 and the luminance of pixel X13 as the luminance difference. The image processing unit 17 outputs the luminance of each pixel X1 of image M2 to the position recognition unit 20.

The position recognition unit 20, for example, determines whether the optical fiber F has reached a fusion-enabled position (step S6, a process for determining whether the optical fiber has reached a fusion-enabled position). The "fusion-enabled position" is, for example, the position of the end face F1 at which the optical fiber F can be fused by the electrode rod 3b.

If the position recognition unit 20 determines in step S6 that the optical fiber F has reached the fusion position, the process proceeds to step S7. On the other hand, if the position recognition unit 20 determines in step S6 that the optical fiber F has not reached the fusion position, the process returns to step S3. Then, the drive unit 14 finely moves the optical fiber F, the microscope 15 captures the optical fiber F to obtain an image M3, and then the image processing unit 17 calculates the brightness difference described above for image M3.

For example, if the position recognition unit 20 determines that the optical fiber F has not reached the fusion position, the drive unit 14 again finely moves the optical fiber F, the microscope 15 images the optical fiber F to obtain image M4, and then the image processing unit 17 calculates the brightness difference described above for image M4. For example, after obtaining image M5 in the same manner as above, the image processing unit 17 calculates the brightness difference described above for image M5. Then, if the position recognition unit 20 determines that the optical fiber F has reached the fusion position (YES in step S6), the position recognition unit 20 recognizes the reference position (step of recognizing the reference position, step S7).

In step S7, the position recognition unit 20 recognizes the position of the end face F1 of the optical fiber F in image M3, of the captured images M1, M2, M3, M4, and M5, in which the position of the end face F1 is closest to one side of pixel X1, as the reference position Y. More specifically, the position recognition unit 20 recognizes the position of the end face F1 of the optical fiber F in image M3, in which the luminance difference between the two pixels X11 and X13 aligned along the Z-axis direction is maximum, as the reference position Y.

As a specific example, pixel X13 is blurred in images M1 and M2 compared to image M3. That is, the luminance difference of pixel X13 relative to the luminance of pixel X11 is small, so the position recognition unit 20 cannot accurately recognize the position of end face F1 at the time when images M1 and M2 are captured. In contrast, when image M3 is captured, pixel X13 is clearer than images M1 and M2. That is, the luminance difference of pixel X13 relative to the luminance of pixel X11 is large, so the position recognition unit 20 can accurately recognize the position of end face F1 at the time when image M3 is captured. The position of one side of pixel X1 and the actual position are in a one-to-one relationship. Therefore, the larger the luminance difference of pixel X13 relative to the luminance of pixel X11 is, and the closer the position of the captured end face F1 is to the position of one side of pixel X1, the more accurately the position recognition unit 20 can recognize the position of end face F1.

After recognizing the reference position Y, the position recognition unit 20 recognizes the position of the end face F1 of the optical fiber F (step S8 of recognizing the position of the face of the optical fiber). The position recognition unit 20 stores how many times the optical fiber F has moved a certain distance from the reference position Y. In the example of FIG. 9, the optical fiber F has moved twice from the reference position Y. Therefore, the position recognition unit 20 can accurately recognize the position of the end face F1 at the time when the image M5 is captured by adding the product of the number of times the optical fiber F has moved from the reference position Y and the certain distance as the moving distance to the reference position Y. The position recognition unit 20 may also store the moving distance of the optical fiber F from the reference position Y, and may recognize the position of the end face F1 by adding the moving distance of the optical fiber F from the reference position Y to the reference position Y.

Next, the effects obtained from the fusion splicer 1 and fusion splicing method according to this embodiment will be described. In the fusion splicer 1 and fusion splicing method according to this embodiment, the drive unit 14 moves the stage 11 on which the optical fiber F is placed, and the microscope 15 captures an image of the moving surface of the optical fiber F. The microscope 15 outputs the brightness of the images M1, M2, M3, M4, and M5 obtained by capturing the images for each pixel X1. The position recognition unit 20 recognizes the position of the optical fiber F from the brightness of each pixel X1 of the images M1, M2, M3, M4, and M5. The drive unit 14 moves the optical fiber F at a constant distance shorter than the pixel size of the pixel X1, and the microscope 15 captures an image of the optical fiber F each time the optical fiber F moves the constant distance. The position recognition unit 20 then recognizes the position of the surface of the moved optical fiber F from the multiple brightnesses of the images M1, M2, M3, M4, and M5. Therefore, images M1, M2, M3, M4, and M5 are obtained by capturing images of the optical fiber F as it moves a fixed distance shorter than the pixel size, and the position of the surface of the optical fiber F can be recognized with high accuracy by recognizing the position of the surface of the optical fiber F from the multiple brightnesses of the images M1, M2, M3, M4, and M5. Even if the resolution of the microscope 15 is low and the pixels X1 of the images M1, M2, M3, M4, and M5 are coarse, the position of the surface of the optical fiber F can be accurately recognized from the images M1, M2, M3, M4, and M5 by capturing images M1, M2, M3, M4, and M5 every time the optical fiber F moves a fixed distance shorter than the pixel size.

As described above, the position recognition unit 20 may recognize the position of the surface of the optical fiber F in image M3, which is closest to one side of pixel X1 among images M1, M2, M3, M4, and M5, as the reference position Y. In this case, the position recognition unit 20 can recognize how many times the drive unit 14 has moved the optical fiber F a certain distance from the reference position Y, thereby more accurately recognizing the position of the surface of the optical fiber F after it has been moved.

As described above, the position recognition unit 20 may recognize the position of the optical fiber F in image M3, where the luminance difference between two pixels, pixel X11 and pixel X13, aligned along the Z-axis direction among images M1, M2, M3, M4, and M5, is the largest, as the reference position Y. In this case, the position recognition unit 20 can easily recognize the reference position Y from the luminance difference between pixel X11 and pixel X13, aligned along the Z-axis direction.

The aforementioned fixed distance may be less than half the pixel size. In this case, images M1, M2, M3, M4, and M5 of the optical fiber F are captured every time the optical fiber moves a fixed distance that is less than half the pixel size, and the position of the surface of the optical fiber F can be accurately recognized from the images M1, M2, M3, M4, and M5.

The aforementioned surface may be an end face F1 located at one end in the longitudinal direction of the optical fiber F. In this case, the position of the end face F1 of the optical fiber F can be accurately recognized. As a result, the pair of end faces F1 aligned along the Z-axis direction can be appropriately fused, thereby preventing poor contact.

Next, various modified examples of the fusion splicer and fusion splicing method according to the present disclosure will be described. Some of the modified fusion splicers and fusion splicing methods are the same as some of the fusion splicers and fusion splicing methods according to the embodiments described above. Therefore, in the following, explanations that are the same as those already described will be omitted as appropriate by assigning the same reference numerals.

FIG. 10 is a diagram for explaining a fusion splicing method according to a modified example. In the above-described embodiment, an example was described in which the driving unit 14 fixes one of the two tables 11 and moves the unfixed table 11 along the Z-axis direction. In contrast, in the fusion splicing method according to the modified example, each table 11 is moved a fixed distance so that the pair of optical fibers F approach each other.

Then, as in the above embodiment, an image of each optical fiber F is captured every time the optical fiber F moves a fixed distance. The microscope 15 captures an image of the pair of optical fibers F every time the pair of optical fibers F moves a fixed distance so that they approach each other. The position recognition unit 20 recognizes the position of each end face F1 of each moved optical fiber F from the brightness of the image M6. In this case, the position recognition unit 20 can recognize the distance between the pair of end faces F1. Furthermore, if an imaginary straight line L connecting the pair of electrode rods 3b extends along one side of pixel X2 of image M6, it is possible to calculate the distance of each end face F1 from the imaginary straight line L. Therefore, the fusion splicing of the pair of optical fibers F can be performed more appropriately.

FIG. 11 is a diagram for explaining a fusion splicing method according to another modified example different from that of FIG. 10. FIG. 11 corresponds to FIG. 9 described above, and the direction in which the optical fiber F moves is different from that of FIG. 9. In the modified example shown in FIG. 11, for example, in order to align the optical fiber F, the driving unit 14 moves the optical fiber F a fixed distance along the X-axis direction. The microscope 15 captures the optical fiber F to obtain an image of the side surface F2 of the optical fiber F.

The position recognition unit 20 acquires images M11, M12, M13, M14, and M15 while moving the optical fiber F a fixed distance along the X-axis direction in a manner similar to that used to acquire images M1, M2, M3, M4, and M5 described above. Then, when the position recognition unit 20 recognizes that the optical fiber F has reached an alignment position, the position recognition unit 20 recognizes the reference position. At this time, the position recognition unit 20 recognizes the position of the side surface F2 of the optical fiber F in image M13, among images M11, M12, M13, M14, and M15, in which the position of the side surface F2 is closest to one side of pixel X3, as the reference position Z.

More specifically, the position recognition unit 20 recognizes the position of the side surface F2 of the optical fiber F in image M13 where the luminance difference between two pixels X14, X15 aligned along the X-axis direction is maximum as the reference position Z. After recognizing the reference position Z, the position recognition unit 20 recognizes the position of the side surface F2 of the optical fiber F at the time when the image M15 was captured. Specifically, the position recognition unit 20 can accurately recognize the position of the side surface F2 at the time when the image M15 was captured by adding the product of the number of times the optical fiber F has moved from the reference position Z and a fixed distance to the reference position Z.

As described above, in the example of FIG. 11, the driving unit 14 moves the optical fiber F along the X-axis direction perpendicular to the longitudinal direction of the optical fiber F. The surface of the optical fiber F to be recognized is the side surface F2 of the optical fiber F, which extends along the longitudinal direction of the optical fiber F. In the example of FIG. 11, the position of the side surface F2 of the optical fiber F can be accurately recognized.

FIG. 12 is a diagram for explaining a fusion splicing method according to a modified example different from those in FIGS. 10 and 11. In the example of FIG. 12, the drive unit 14 moves each of a pair of optical fibers F aligned along the Z-axis direction along the X-axis direction. Then, the microscope 15 images the pair of optical fibers F every time each optical fiber F moves a certain distance along the X-axis direction. The position recognition unit 20 recognizes the position of each side surface F2 of each moved optical fiber F from the brightness of the image M7. In this case, the position recognition unit 20 can recognize the position of each side surface F2 of the pair of optical fibers F in the X-axis direction. Therefore, the positions of the side surfaces F2 of the pair of optical fibers F can be aligned, making it possible to align the pair of optical fibers F with high precision.

The above describes the embodiments and various modifications of the fusion splicer and fusion splicing method according to the present disclosure. However, the present invention is not limited to the above-described embodiments or modifications, and may be modified as appropriate within the scope of the gist described in the claims. The shape, size, number, material, and arrangement of each part of the fusion splicer are not limited to the above-described embodiments or modifications, and may be modified as appropriate within the scope of the above-described gist. The content and order of the steps of the fusion splicing method are not limited to the above-described embodiments or modifications, and may be modified as appropriate within the scope of the above-described gist. A fusion splicer or fusion splicing method may be a combination of multiple forms of the above-described embodiments and various modifications.

For example, in the above embodiment, an example was described in which the driving unit 14 is a stepping motor, and the fixed distance, which is the amount of movement of the optical fiber F by the driving unit 14 per movement, is 1 μm or more and less than 10 μm. Then, an example was described in which the microscope 15 images the optical fiber F every time the optical fiber F moves a fixed distance. For example, the microscope 15 may image the optical fiber F every time the driving unit 14 moves the optical fiber F by one pulse, or the microscope 15 may image the optical fiber F every time the driving unit 14 moves the optical fiber F by two pulses. In this way, the frequency at which the microscope 15 images the optical fiber F can be changed as appropriate. However, in order to perform position recognition with even higher accuracy, it is desirable for the microscope 15 to image the optical fiber F every time the driving unit 14 moves the optical fiber F by one pulse. In addition, the driving unit may be something other than a stepping motor, and the type of the driving unit is not particularly limited.

DESCRIPTION OF SYMBOLS 1...Fusion splicer 2...Housing 3...Fusion splicing section 3a...Fiber positioning section 3b...Electrode rod 3c...Fiber holder 4...Heater 5...Monitor 6...Windshield cover 7...Power switch 8...Connection start switch 11...Base 12...Main surface 13...V-groove 14...Drive section 15...Microscope 16...Imaging element 17...Image processing section 20...Position recognition section F...Optical fiber F1...End face F2...Side L...Virtual straight line M1, M2, M3, M4, M5, M6, M7, M11, M12, M13, M14, M15...Image P...Position X, X1, X2, X3, X11, X12, X13, X14, X15...Pixel Y, Z...Reference position

Claims

a stand on which the optical fiber is placed;
A drive unit that moves the platform;
a microscope that captures an image of the optical fiber and outputs the brightness of the image obtained by capturing the image for each pixel;
a position recognition unit that recognizes the position of the surface of the optical fiber from the brightness of each pixel output by the microscope;
Equipped with
The driving unit moves the optical fiber by a fixed distance,
the certain distance is shorter than a pixel size of the pixel,
the microscope captures an image of the optical fiber every time the driving unit moves the optical fiber by the certain distance;
the position recognition unit recognizes a position of the surface of the optical fiber moved by the drive unit from the plurality of the luminances of the plurality of the images obtained by the microscope.
Fusion splicer.
the position recognition unit recognizes, as a reference position, a position of the surface of the optical fiber in an image in which the position of the surface of the optical fiber is closest to one side of the pixel, among the plurality of images;
The fusion splicer of claim 1.
the position recognition unit recognizes, as the reference position, a position of the optical fiber in an image in which a luminance difference between two of the pixels aligned along a moving direction of the optical fiber is maximum among the plurality of images;
The fusion splicer of claim 2.
the position recognition unit stores a moving distance of the optical fiber from the reference position, and recognizes a position of the surface by adding the moving distance of the optical fiber from the reference position to the reference position.
The fusion splicer according to claim 2 or 3.
the position recognition unit stores how many times the optical fiber has moved the fixed distance from the reference position, and recognizes the position of the surface by adding the product of the number of times the optical fiber has moved from the reference position and the fixed distance to the reference position as the moving distance.
The fusion splicer of claim 4.
The driving unit moves the optical fiber along a longitudinal direction of the optical fiber.
The fusion splicer according to any one of claims 1 to 5.
The driving unit moves the optical fiber in a direction perpendicular to a longitudinal direction of the optical fiber.
The fusion splicer according to any one of claims 1 to 5.
The fixed distance is equal to or less than half the pixel size.
The fusion splicer according to any one of claims 1 to 7.
The surface is an end surface of the optical fiber located at one end in a longitudinal direction of the optical fiber.
The fusion splicer according to any one of claims 1 to 8.
The face is a side face of the optical fiber extending along a longitudinal direction of the optical fiber.
The fusion splicer according to any one of claims 1 to 8.
The microscope includes an image pickup element that picks up an image of the optical fiber, and an image processing unit that processes an image of the optical fiber picked up by the image pickup element,
The image processing unit outputs the luminance of the image for each pixel.
The fusion splicer according to any one of claims 1 to 10.
The image processing unit calculates a luminance difference between two of the pixels aligned along a moving direction of the optical fiber,
The position recognition unit stores the luminance difference calculated by the image processing unit.
The fusion splicer of claim 11.
a multi-fiber fusion splicer that fusion-splices a plurality of the optical fibers together;
The fusion splicer according to any one of claims 1 to 12.
The position recognition unit stores an image captured by the microscope and recognizes a position of the optical fiber from the brightness of each output pixel.
The fusion splicer according to any one of claims 1 to 13.
the position recognition unit recognizes, as the position of the surface, a position of the pixel between the pixel with the highest luminance and the pixel with the lowest luminance among the plurality of pixels;
The fusion splicer according to any one of claims 1 to 14.
moving a table on which the optical fiber is placed;
imaging the optical fiber;
outputting the luminance of the image obtained by the imaging step for each pixel;
Recognizing the position of the surface of the optical fiber from the luminance of each pixel;
Equipped with
In the moving step, the optical fiber is moved by a fixed distance at a time,
the certain distance is shorter than a pixel size of the pixel,
In the imaging step, an image of the optical fiber is captured every time the optical fiber moves the certain distance;
In the step of recognizing the position, a position of the surface of the optical fiber that has been moved is recognized based on the plurality of luminances of the plurality of images.
Fusion splicing method.