Fusion splicing device and fusion splicing method

Abstract

A fusion splicing device (1) according to one embodiment comprises: a platform (11) on which an optical fiber (F) is placed; a drive unit (14) that moves the platform (11); a microscope (15) that images the optical fiber (F) and outputs the brightness of each pixel in the image obtained by the imaging; and a position recognition unit (20) that recognizes the position of a face of the optical fiber based on the brightness of each pixel output by the microscope (15). The drive unit (14) moves the optical fiber (F) in increments of a fixed distance. The fixed distance is shorter than the pixel size of the pixels. The microscope (15) images the optical fiber (F) every time the drive unit (14) moves the optical fiber (F) by the fixed distance. The position recognition unit (20) recognizes the position of the face of the optical fiber (F) which has been moved by the drive unit (14) on the basis of the plurality of brightnesses of the plurality of pixels obtained by the microscope (15).

Description

Fusion splicer and fusion splicing method

[0001] This application claims priority to International Application No. PCT / JP2022 / 046279 filed on December 15, 2022, and incorporates by reference the entire contents of that application.

[0002] Patent Document 1 describes an optical fiber fusion splicer. The optical fiber fusion splicer splices a pair of optical fibers together while melting the optical fibers. The optical fiber fusion splicer has a fiber feed unit that holds a plurality of optical fibers. The fiber feed unit moves the plurality of 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 unit that processes image data captured by the camera to recognize the movement of the optical fibers. The image data processing unit performs image data processing to recognize the operation of the optical fibers from differences in the plurality of image data.

[0003] Patent Document 2 describes a method and device for fusion splicing optical fibers. The splicing device includes a mounting section on which an optical fiber is placed, a holder for holding a plurality of optical fibers, and a TV camera for photographing the plurality of optical fibers. The TV camera is provided to measure the axial misalignment of the optical fibers.

[0004] 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 to an image processing device as an imaging signal. The image processing device includes a calculation unit that performs calculations for aligning the optical fiber based on the imaging signal and generates a processing signal, and a control unit that controls the operation of the fine alignment mechanism in accordance with the processing signal from the calculation unit.

[0005] JP 2005-189770, JP 10-239553, JP 5-164934

[0006] The fusion splicer according to the present disclosure includes a stage on which an optical fiber is placed, a drive unit that moves the stage, a microscope that images the optical fiber and outputs the brightness of the image obtained by the image capture for each pixel, and 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. The drive unit moves the optical fiber in fixed distance increments. The fixed distance is shorter than the pixel size of the pixels. The microscope images the optical fiber each 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 brightness values ​​of multiple images obtained by the microscope.

[0007] 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 an embodiment. FIG. 3 is a perspective view showing a fusion splicer base and an optical fiber according to an embodiment. FIG. 4 is a block diagram showing the functional configuration of the fusion splicer according to an embodiment. FIG. 5 is a schematic view showing an image of an optical fiber captured by a microscope. FIG. 6 is a view showing the position of the optical fiber in an image obtained by capturing the image. FIG. 7 is a view showing an image of the optical fiber obtained by capturing the image. FIG. 8 is a flowchart showing an example of steps of a fusion splicing method according to an embodiment. FIG. 9 is a diagram for explaining the procedure of moving an optical fiber, capturing the image of the optical fiber, and recognizing the position of the optical fiber. FIG. 10 is a diagram for explaining the procedure of moving an optical fiber, capturing the image of the optical fiber, and recognizing the position of the optical fiber according to a modified example. FIG. 11 is a diagram for explaining the procedure of moving an optical fiber, capturing the image of the optical fiber, and recognizing the position of the optical fiber according to a modified example different from FIG. 10. FIG. 12 is a diagram for explaining the procedure of moving an optical fiber, capturing the image of the optical fiber, and recognizing the position of the optical fiber according to a modified example different from FIG. 9 and FIG. 10. Fig. 13 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 further modified example. Fig. 14 is a diagram showing the position of the surface of the optical fiber measured by the procedure of Fig. 13. Fig. 15 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 further modified example. Fig. 16 is a diagram showing the position of the surface of the optical fiber measured by the procedure of Fig. 15.

[0008] 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 this case, the resolution of the microscope is often low. Therefore, the image of the optical fiber is coarse, and the position of the surface of the optical fiber may not be accurately recognized. For example, if the position of the end face of the optical fiber to be fusion-spliced ​​cannot be accurately recognized, connection loss of the optical fiber may occur.

[0009] An object of the present disclosure is to provide a fusion splicer that can accurately recognize the position of the surface of an optical fiber.

[0010] [Description of Embodiments of the Present Disclosure] First, 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 that moves the stage; a microscope that captures an image of the optical fiber and outputs the brightness of the captured image for each pixel; and 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. The drive unit moves the optical fiber by a fixed distance. The fixed distance is shorter than the pixel size of the pixel. The microscope captures an image of the optical fiber each 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.

[0011] In this fusion splicer, a drive unit moves a stage on which the optical fiber is placed, and a microscope captures an image of the moving optical fiber surface. The microscope outputs the brightness of the image obtained by capturing the image for each pixel. The position recognition unit recognizes the position of the optical fiber from the brightness of each pixel in the image. The drive unit moves the optical fiber in increments of a fixed distance shorter than the pixel size, and the microscope captures an image of the optical fiber each time the optical fiber moves the 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, by obtaining an image each time the optical fiber moves a fixed distance shorter than the pixel size and recognizing the position of the optical fiber surface from the multiple brightnesses of the multiple images, the position of the optical fiber surface can be recognized with high accuracy. Even if the resolution of the microscope is low and the image pixels are coarse, by capturing an image each time the optical fiber 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.

[0012] (2) In the above (1), the position recognition unit may recognize, as the reference position, the position of the optical fiber surface in an image in which the position of the optical fiber surface is closest to one side of a pixel among the multiple images. In this case, the position recognition unit can more accurately recognize the position of the optical fiber surface after movement by recognizing how many times the drive unit has moved the optical fiber a certain distance from the reference position.

[0013] (3) In the above (2), 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 difference in brightness between two pixels aligned along the moving direction of the optical fiber is the largest. In this case, the position recognition unit can easily recognize the reference position from the difference in brightness between two pixels aligned along the moving direction.

[0014] (4) In (2) or (3) above, the position recognition unit may store the distance the optical fiber has moved from a reference position, or may recognize the position of the surface by adding the distance the optical fiber has moved from the reference position to the reference position.

[0015] (5) In (4) above, the position recognition unit may store the number of times the optical fiber has moved a certain 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 certain distance as the moving distance to the reference position.

[0016] (6) In any of (1) to (5) above, the position recognition unit may recognize the position of the optical fiber for each pixel aligned in a direction perpendicular to the moving direction in an image among the multiple images in which the difference in brightness between two pixels aligned along the moving direction of the optical fiber is greatest. In this case, since the position of the optical fiber is recognized for each pixel aligned in the direction perpendicular to the moving direction, it is possible to measure the position of the surface of the optical fiber in detail even if the shape of the surface is complex.

[0017] (7) In the above (6), the position recognition unit may store the number of times the optical fiber has moved a certain distance, and may recognize the position of the surface by subtracting the product of the number of times the optical fiber has moved and the certain distance from the position of the optical fiber in the image where the brightness difference is greatest. In this case, the position of the surface of the optical fiber before movement can be measured.

[0018] (8) In the above (6) or (7), the position recognition unit may recognize the position of the surface for each pixel aligned in a direction perpendicular to the movement direction. In this case, the position of the surface of the optical fiber before movement can be measured in more detail.

[0019] (9) In any one of the above (1) to (8), the driving unit may move the optical fiber along the longitudinal direction of the optical fiber.

[0020] (10) In any one of the above (1) to (8), the driving unit may move the optical fiber in a direction perpendicular to the longitudinal direction of the optical fiber.

[0021] (11) In any of the above (1) to (10), the predetermined 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 predetermined distance equal to or less than half the pixel size, so that the position of the optical fiber surface can be recognized more accurately from the multiple images.

[0022] (12) In any of the above (1) to (11), 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.

[0023] (13) In any of the above (1) to (11), 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.

[0024] (14) In any one of (1) to (13) above, the microscope may include 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.

[0025] (15) In (14) above, the image processing unit may calculate the brightness difference between two pixels aligned along the movement direction of the optical fiber, and the position recognition unit may store the brightness difference calculated by the image processing unit.

[0026] (16) In any of the above (1) to (15), the fusion splicer may be a multi-fiber fusion splicer that fusion-splices a plurality of optical fibers together.

[0027] (17) In any of the above (1) to (16), 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.

[0028] (18) In any of (1) to (17) above, the position recognition unit may recognize the position of a pixel between the pixel with the highest brightness and the pixel with the lowest brightness as the position of the surface among the plurality of pixels.

[0029] A fusion splicing method according to one embodiment (19) comprises 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 the 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.

[0030] In this fusion splicing method, as with the fusion splicer described above, the surface of the moving optical fiber is imaged, and the brightness of the image obtained by image capture is output for each pixel. In the position recognition step, 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 moved optical fiber is recognized from multiple brightnesses of multiple images. Therefore, as with 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 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 image pixels are coarse, by capturing an image every time the optical fiber 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 image capture.

[0031] [Details of the embodiment of the present invention] Specific examples 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 designated by the same reference numerals, and duplicate explanations 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.

[0032] 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 unit 3 that fusion splices optical fibers together. The fusion splicer 1 has a monitor 5 that displays the state of the fusion splicing of the optical fibers as imaged by a microscope 15 (see FIG. 4 ), which will be described later. The fusion splicer 1 also has a heater 4 that heats and shrinks a fiber reinforcement sleeve that covers the spliced ​​portion of the optical fibers fused in the fusion splicing unit 3, a power switch 7 that turns the power of the fusion splicer 1 on and off, and a splicing start switch 8 that fusion splices the optical fibers.

[0033] 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 optical fiber 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 surface 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.

[0034] The windshield cover 6 is connected to the housing 2 so as to be able to open and close freely and cover the fusion splicing unit 3. The power switch 7 is a push button for turning the power of the fusion splicer 1 on and off in response to operation by the user of the fusion splicer 1. The splicing start switch 8 is a push button for starting the operation of fusing optical fibers together in response to operation by the user.

[0035] Fig. 3 is a perspective view schematically showing the detailed structure of the fusion splicer 3. As shown in Fig. 3, the fusion splicer 1 has a table 11 on which a plurality of optical fibers F to be fusion spliced ​​are placed. In this embodiment, the fusion splicer 1 is a multi-fiber fusion splicer that fusion-splices a plurality of optical fibers F all at once. The fusion splicer 1 has a pair of tables 11 aligned along the Z-axis direction.

[0036] The base 11 has a main surface 12 on which multiple optical fibers F are placed, and multiple V-grooves 13 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 an 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 a Y-axis direction that intersects with both the X-axis and Z-axis directions. The Y-axis direction is, for example, a direction perpendicular to both the X-axis and Z-axis directions. 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 is arranged on each side of the multiple optical fibers F in the X-axis direction.

[0037] 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 imaginary line L connecting the pair of electrode rods 3b to the end face F1 is a predetermined distance. By performing this adjustment on the pair of optical fibers F arranged along the Z-axis direction by the drive unit 14, the optical fibers F can be appropriately fusion spliced ​​using the pair of electrode rods 3b.

[0038] The driver 14 is, for example, a stepping motor. In this case, the driver 14 is driven in response to the applied pulse voltage. The stage 11 moves along the Z-axis direction as a result of the driver 14 driving. For example, the driver 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 movement of a distance shorter than the pixel size of an image captured by the microscope 15 (described later). Furthermore, "pixel size" here refers to the length measured along the movement direction of the optical fiber F. The driver 14 finely moves the optical fiber F by a fixed distance at a time. The "fixed distance" refers, for example, to the amount of movement of the optical fiber F per pulse by the driver 14. For example, the "fixed distance" is equal to or greater than 1 μm and less than 10 μm. As an example, the "fixed distance" is 2 μm.

[0039] Fig. 4 is a block diagram showing the functions of the microscope 15 and the position recognition unit 20. Fig. 5 is a diagram showing an image captured by the microscope 15. As shown in Figs. 4 and 5, the fusion splicer 1 has a microscope 15 that captures an image of the 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 the multiple optical fibers F placed on each of the pair of stages 11. The microscope 15 is, for example, a charge-coupled device camera (CCD camera) or a complementary metal oxide semiconductor camera (CMOS camera).

[0040] The microscope 15 includes, 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 aforementioned certain distance. For example, the pixel size of the image captured by the image sensor 16 is at least twice the aforementioned certain distance. This pixel size is set to a large value because the fusion splicer 1 is a multi-fiber fusion splicer and needs to capture images of multiple optical fibers F arranged along the X-axis direction. As an example, the pixel size is 10 μm.

[0041] For example, a CPU (Central Processing Unit) configured with one or more integrated circuits (ICs) is used as the position recognition unit 20. 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.

[0042] 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 the captured image of the 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 becomes blurred, and it may happen that the position recognition unit 20 is unable to recognize the exact position of the end face F1. More specifically, although the position recognition unit 20 can recognize that the end face F1 is located in a blurred pixel X portion in the image, it may be unable to recognize the position within pixel X where the end face F1 is located.

[0043] Meanwhile, the driver 14 fine-tunes the position of the end face F1 in the Z-axis direction 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, the end face F1 may not be in an appropriate position, and fusion splicing may not be performed properly. In this case, a 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 will be described below.

[0044] Fig. 8 is a flowchart showing an example of steps in 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 tables 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 tables 11, and the optical fibers F are placed on each table 11 so that multiple optical fibers F are lined up along the X-axis direction.

[0045] 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 located 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.

[0046] Next, the driver 14 moves the stage 11 on which the optical fiber F is placed (stage moving step). For example, the driver 14 fixes one of the two stages 11 and moves the unfixed stage 11 along the Z-axis direction. At this time, the driver 14 finely moves the optical fiber F to move the optical fiber F a certain distance in the Z-axis direction (step S3). Thereafter, 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.

[0047] 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 for 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.

[0048] The position recognition unit 20 determines, for example, whether the optical fiber F has reached a fusion-capable position (step S6 for determining whether the optical fiber has reached a fusion-capable position). The "fusion-capable 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.

[0049] If the position recognition unit 20 determines in step S6 that the optical fiber F has reached the fusion splice 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 splice position, the process returns to step S3. Then, after the drive unit 14 finely moves the optical fiber F and the microscope 15 captures an image of the optical fiber F to obtain an image M3, the image processing unit 17 calculates the brightness difference described above for image M3.

[0050] For example, if the position recognition unit 20 determines that the optical fiber F has not reached the fusion-capable position, the drive unit 14 again finely moves the optical fiber F, and the microscope 15 captures an image of the optical fiber F to obtain an image M4, after which the image processing unit 17 calculates the above-mentioned luminance difference for image M4. For example, after obtaining an image M5 in the same manner as above, the image processing unit 17 calculates the above-mentioned luminance difference for image M5. Then, if the position recognition unit 20 determines that the optical fiber F has reached the fusion-capable position (YES in step S6), the position recognition unit 20 recognizes the reference position (step of recognizing the reference position, step S7).

[0051] In step S7, the position recognition unit 20 recognizes the position of the end face F1 of the optical fiber F in image M3, among the captured images M1, M2, M3, M4, and M5, in which the position of the end face F1 of the optical fiber F 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 difference in brightness between two pixels X11 and X13 aligned along the Z-axis direction is maximum, as the reference position Y.

[0052] As a specific example, pixel X13 is blurred in images M1 and M2 compared to image M3. That is, because the difference in luminance of pixel X13 relative to the luminance of pixel X11 is small, the position recognition unit 20 cannot accurately recognize the position of end face F1 at the time images M1 and M2 are captured. In contrast, when image M3 is captured, pixel X13 is clearer than in images M1 and M2. That is, because the difference in luminance of pixel X13 relative to the luminance of pixel X11 is large, the position recognition unit 20 can accurately recognize the position of end face F1 at the time image M3 is captured. The position of one side of pixel X1 and its actual position correspond to one-to-one. Therefore, the greater the difference in luminance of pixel X13 relative to the luminance of pixel X11 and the closer the captured position of 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.

[0053] 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 was 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 movement distance to the reference position Y. Alternatively, the position recognition unit 20 may store the movement distance of the optical fiber F from the reference position Y and recognize the position of the end face F1 by adding the movement distance of the optical fiber F from the reference position Y to the reference position Y.

[0054] Next, the effects obtained by 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 images of the moving surface of the optical fiber F. The microscope 15 outputs the brightness of the captured images M1, M2, M3, M4, and M5 for each pixel X1. The position recognition unit 20 recognizes the position of the optical fiber F from the brightness of each pixel X1 in the images M1, M2, M3, M4, and M5. The drive unit 14 moves the optical fiber F in increments of a fixed 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 fixed distance. The position recognition unit 20 then recognizes the position of the moved surface of the optical fiber F from the multiple brightness values ​​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 brightness levels 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.

[0055] As described above, the position recognition unit 20 may recognize the position of the surface of the optical fiber F in image M3, among images M1, M2, M3, M4, and M5, where the position of the surface is closest to one side of pixel X1, as the reference position Y. In this case, the position recognition unit 20 can more accurately recognize the position of the surface of the optical fiber F after movement by recognizing how many times the driving unit 14 has moved the optical fiber F a certain distance from the reference position Y.

[0056] As described above, the position recognition unit 20 may recognize the position of the optical fiber F in image M3, among images M1, M2, M3, M4, and M5, where the difference in luminance between two pixels, pixel X11 and pixel X13, aligned along the Z-axis direction is greatest, as the reference position Y. In this case, the position recognition unit 20 can easily recognize the reference position Y from the difference in luminance between pixel X11 and pixel X13, aligned along the Z-axis direction.

[0057] The above-mentioned certain distance may be equal to or 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 F moves a certain distance equal to or less than half the pixel size, so that the position of the surface of the optical fiber F can be accurately recognized from the images M1, M2, M3, M4, and M5.

[0058] The aforementioned surface may be an end face F1 located at one longitudinal end of the optical fiber F. In this case, it is possible to accurately recognize the position of the end face F1 of the optical fiber F. As a result, it is possible to appropriately fusion-splice a pair of end faces F1 aligned along the Z-axis direction, thereby suppressing the occurrence of poor contact.

[0059] Next, various modified examples of the fusion splicer and fusion splicing method according to the present disclosure will be described. Some of the fusion splicers and fusion splicing methods according to the modified examples are the same as some of the fusion splicers and fusion splicing methods according to the above-described embodiments. Therefore, in the following, the same explanations as those already given will be omitted as appropriate, with the same reference numerals used.

[0060] 10 is a diagram illustrating a fusion splicing method according to a modified example. In the above-described embodiment, an example was described in which the driver 14 fixed one of the two bases 11 and moved the unfixed base 11 along the Z-axis direction. In contrast, in the fusion splicing method according to the modified example, each base 11 is moved by a fixed distance so that the pair of optical fibers F approach each other.

[0061] As in the above-described embodiment, an image of each optical fiber F is captured each time the optical fiber F moves a certain distance. The microscope 15 captures an image of the pair of optical fibers F each time the pair of optical fibers F moves a certain distance so as to 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 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 line L. This allows the pair of optical fibers F to be fusion spliced ​​more appropriately.

[0062] Figure 11 is a diagram for explaining a fusion splicing method according to a different modification from that shown in Figure 10. Figure 11 corresponds to the above-mentioned Figure 9, but the direction in which the optical fiber F moves is different from that shown in Figure 9. In the modification shown in Figure 11, for example, in order to align the optical fiber F, the driver 14 moves the optical fiber F a fixed distance along the X-axis direction. The microscope 15 captures the optical fiber F, thereby obtaining an image of the side surface F2 of the optical fiber F.

[0063] The position recognition unit 20 acquires images M11, M12, M13, M14, and M15 while moving the optical fiber F a certain distance along the X-axis direction in a manner similar to that used to acquire the 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 as the reference position Z the position of the side surface F2 of the optical fiber F in image M13, among the images M11, M12, M13, M14, and M15, where the position of the side surface F2 is closest to one side of pixel X3.

[0064] More specifically, the position recognition unit 20 recognizes the position of the side surface F2 of the optical fiber F in the image M13 where the difference in brightness between two pixels X14 and 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 to the reference position Z the product of the number of times the optical fiber F has moved from the reference position Z and a certain distance.

[0065] 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 extending 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.

[0066] Fig. 12 is a diagram illustrating a fusion splicing method according to a modified example different from Figs. 10 and 11 . In the example of Fig. 12 , a driver 14 moves each of a pair of optical fibers F aligned along the Z-axis direction along the X-axis direction. Then, a microscope 15 captures an image of the pair of optical fibers F every time each optical fiber F moves a fixed distance along the X-axis direction. A position recognition unit 20 recognizes the position of each side surface F2 of each optical fiber F that has moved based on 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, enabling highly accurate alignment of the pair of optical fibers F.

[0067] Next, a fusion splicer according to a modified example will be described with reference to Fig. 13 and Fig. 14. Fig. 13 is a diagram for explaining the fusion splicing method using the fusion splicer according to the modified example. Fig. 14 is a diagram showing an image M24 of a surface measured by the above fusion splicing method. The position recognition unit 20 of the fusion splicer according to the modified example stores the number of times the optical fiber F has moved.

[0068] FIG. 13(1) is a diagram showing an image M21 of the optical fiber F before movement. FIG. 13(2) is a diagram showing an image M22 of the optical fiber F after one movement in the Z-axis direction. FIG. 13(3) is a diagram showing an image M23 of the optical fiber F after two movements in the Z-axis direction. As an example, if the size of one side of pixel X1 is A (μm) (A is a positive real number), the movement distance (constant distance) of the optical fiber F per movement is A / B (μm) (B is a natural number). In this case, when the optical fiber F moves B times, the movement distance of the optical fiber F becomes the length of one side of one pixel X1. In other words, the movement distance of the optical fiber F is 1 / B of the length of one side of pixel X1. As an example, the value of A is 10, and the value of B is 3.

[0069] The following describes a fusion splicing method using a fusion splicer according to a modified example. First, the microscope 15 captures an image of the optical fiber F to obtain an image M21 of the optical fiber F. The position recognition unit 20 recognizes the position of the optical fiber F in the image M21, M22, and M23 where the difference in brightness between two pixels aligned along the Z-axis direction is greatest, for each pixel X1 aligned in the X-axis direction perpendicular to the Z-axis direction. The position recognition unit 20 recognizes that in the third group of pixels X1 in the X-axis direction of the image M21, the difference in brightness between pixel X21 and pixel X22 is greatest, and recognizes the position between pixel X21 and pixel X22 as the position of the end face of the optical fiber F. The group of pixels X1 refers to a collection of multiple pixels X1 aligned along the movement direction of the optical fiber F.

[0070] Next, as described above, the optical fiber F is moved a certain distance in the Z-axis direction, and the microscope 15 captures an image of the optical fiber F, thereby obtaining an image M22 of the optical fiber F. The position recognition unit 20 recognizes that in the fifth pixel X1 group in the X-axis direction of the image M22, the difference in luminance between pixel X23 and pixel X24 is greatest, and recognizes the position between pixel X23 and pixel X24 as the position of the end face of the optical fiber F. The position recognition unit 20 recognizes that in the second pixel X1 group in the X-axis direction of the image M22, the difference in luminance between pixel X25 and pixel X26 is greatest, and recognizes the position between pixel X25 and pixel X26 as the position of the end face of the optical fiber F.

[0071] The optical fiber F is further moved a certain distance in the Z-axis direction, and the microscope 15 captures an image of the optical fiber F to obtain an image M23 of the optical fiber F. The position recognition unit 20 recognizes that in the fourth pixel X1 group in the X-axis direction of the image M23, the difference in luminance between pixel X27 and pixel X28 is greatest, and recognizes the position between pixel X27 and pixel X28 as the position of the end face of the optical fiber F. The position recognition unit 20 recognizes that in the first pixel X1 group in the X-axis direction of the image M23, the difference in luminance between pixel X29 and pixel X30 is greatest, and recognizes the position between pixel X29 and pixel X30 as the position of the end face of the optical fiber F.

[0072] The position recognition unit 20 recognizes the position of the end face of the optical fiber F before movement by subtracting the product of the number of times the optical fiber F is moved and the fixed distance from the position of the optical fiber F in the images M21, M22, and M23 where the brightness difference is greatest. This position recognition is performed for each pixel X1 aligned in the X-axis direction. Specifically, the position recognition unit 20 recognizes the position of the optical fiber F in the third group of pixels X1 in the X-axis direction by subtracting 0 (0 (number of times the optical fiber F is moved) × (A / B) (fixed distance)) from the position of the optical fiber F in the image M21. That is, the position recognition unit 20 recognizes the position between pixel X21 and pixel X22 in the third group of pixels X1 in the X-axis direction as the position of the end face of the optical fiber F before movement.

[0073] The position recognition unit 20 recognizes the position of the optical fiber F at the second and fifth pixels X1 in the X-axis direction by subtracting A / B (1 (number of movements) × (A / B) (fixed distance)) from the position of the optical fiber F in image M22. That is, for the second group of pixels X1 in the X-axis direction, the position recognition unit 20 recognizes a position moved by 1 / B pixel in the opposite direction of the Z-axis direction from the position between pixels X25 and X26 as the position of the end face of the optical fiber F. The result is shown as image M24 in Figure 14. For the fifth group of pixels X1 in the X-axis direction, the position recognition unit 20 recognizes a position moved by 1 / B pixel in the opposite direction of the Z-axis direction from the position between pixels X23 and X24 as the position of the end face of the optical fiber F.

[0074] The position recognition unit 20 recognizes the position of the optical fiber F at the first and fourth pixels X1 in the X-axis direction by subtracting 2A / B (2 (number of movements) × (A / B) (fixed distance)) from the position of the optical fiber F in the image M23. That is, for the first group of pixels X1 in the X-axis direction, the position recognition unit 20 recognizes a position moved by 2 / B in the opposite direction of the Z-axis direction from a position between pixels X29 and X30 as the position of the end face of the optical fiber F. For the fourth group of pixels X1 in the X-axis direction, the position recognition unit 20 recognizes a position moved by 2 / B in the opposite direction of the Z-axis direction from a position between pixels X27 and X28 as the position of the end face of the optical fiber F. As described above, the position recognition unit 20 recognizes the position of the end face of the optical fiber F before movement for each group of pixels X1 lined up in the X-axis direction, thereby making it possible to grasp the shape of the end face of the optical fiber F.

[0075] In the fusion splicer according to the modified example, the position recognition unit 20 recognizes the position of the optical fiber F for each pixel X1 aligned in a direction perpendicular to the movement direction (X-axis direction) in the image M21, M22, and M23 in which the difference in brightness between two pixels X1 aligned along the movement direction (Z-axis direction) of the optical fiber F is greatest. Because the position of the optical fiber F is recognized for each pixel X1 aligned in the direction perpendicular to the movement direction, the position of the end face of the optical fiber F can be measured in detail even if the shape of the end face is complex.

[0076] As described above, the position recognition unit 20 may store how many times the optical fiber F has moved a certain distance, and may recognize the position of the end face of the optical fiber F by subtracting the product of the number of times the optical fiber F has moved and the certain distance from the position of the optical fiber F in the image where the brightness difference is greatest. In this case, the position of the end face of the optical fiber F before it is moved can be measured.

[0077] As described above, the position recognition unit 20 may recognize the position of the end face of the optical fiber F for each pixel X1 aligned in a direction perpendicular to the movement direction. In this case, the position of the end face of the optical fiber F before movement can be measured in more detail.

[0078] Next, a fusion splicer according to a further modified example will be described with reference to Figs. 15 and 16. Fig. 15 is a diagram for explaining the fusion splicing method using this fusion splicer. Fig. 16 is a diagram showing an image M34 of a surface measured by the above-mentioned fusion splicing method. The configuration of part of the fusion splicer according to this modified example is the same as the configuration of part of the fusion splicer according to Figs. 13 and 14. Below, descriptions that overlap with the fusion splicer according to Figs. 13 and 14 will be omitted as appropriate.

[0079] Fig. 15(1) is a diagram showing an image M31 of the optical fiber F before movement. Fig. 15(2) is a diagram showing an image M32 of the optical fiber F after one movement in the X-axis direction. Fig. 15(3) is a diagram showing an image M33 of the optical fiber F after two movements in the X-axis direction. The position recognition unit 20 recognizes the position of the optical fiber F in the image M31, M32, or M33 in which the brightness difference between two pixels aligned along the X-axis direction is greatest, for each pixel X1 aligned in the Z-axis direction, which is orthogonal to the X-axis direction.

[0080] The position recognition unit 20 recognizes that in the fourth pixel X1 group in the Z-axis direction of image M31, the luminance difference between pixel X31 and pixel X32 is maximum, and recognizes the position between pixel X31 and pixel X32 as the position of the side surface of optical fiber F. The position recognition unit 20 recognizes that in the first pixel X1 group in the Z-axis direction of image M31, the luminance difference between pixel X33 and pixel X34 is maximum, and recognizes the position between pixel X33 and pixel X34 as the position of the side surface of optical fiber F.

[0081] Next, the optical fiber F is moved a certain distance in the X-axis direction, and the microscope 15 captures an image of the optical fiber F, thereby obtaining an image M32 of the optical fiber F. The position recognition unit 20 recognizes that in the second pixel X1 group in the Z-axis direction of the image M32, the difference in brightness between pixel X35 and pixel X36 is greatest, and recognizes the position between pixel X35 and pixel X36 as the position of the side surface of the optical fiber F.

[0082] The optical fiber F is further moved a certain distance in the X-axis direction, and the microscope 15 captures an image of the optical fiber F to obtain an image M33 of the optical fiber F. The position recognition unit 20 recognizes that in the third pixel X1 group in the Z-axis direction of the image M33, the difference in brightness between pixel X37 and pixel X38 is greatest, and recognizes the position between pixel X37 and pixel X38 as the position of the side surface of the optical fiber F.

[0083] The position recognition unit 20 recognizes the position of the optical fiber F in the fourth group of pixels X1 in the Z-axis direction by subtracting 0 (0 (number of movements) × (A / B) (fixed distance)) from the position of the optical fiber F in the image M31. That is, the position recognition unit 20 recognizes the position between pixel X31 and pixel X32 in the fourth group of pixels X1 in the Z-axis direction as the position of the side of the optical fiber F before movement. The position recognition unit 20 recognizes the position between pixel X33 and pixel X34 in the first group of pixels X1 in the Z-axis direction as the position of the side of the optical fiber F before movement.

[0084] The position recognition unit 20 recognizes the position of the optical fiber F at the second pixel X1 in the Z-axis direction by subtracting A / B (1 (number of movements) × (A / B) (fixed distance)) from the position of the optical fiber F in image M32. The result is shown as image M34 in FIG. 16 . That is, in the second group of pixels X1 in the Z-axis direction, the position recognition unit 20 recognizes the position moved by 1 / B pixels in the opposite direction of the X-axis direction from the position between pixel X35 and pixel X36 as the position of the side of the optical fiber F.

[0085] The position recognition unit 20 recognizes the position of the optical fiber F at the third pixel X1 in the Z-axis direction by subtracting 2A / B (2 (number of movements) × (A / B) (fixed distance)) from the position of the optical fiber F in the image M33. That is, for the third group of pixels X1 in the Z-axis direction, the position recognition unit 20 recognizes a position moved by 2 / B in the opposite direction of the X-axis direction from the position between pixels X37 and X38 as the position of the side of the optical fiber F. As described above, the position recognition unit 20 recognizes the position of the side of the optical fiber F before movement for each group of pixels X1 lined up in the Z-axis direction, and thereby the shape of the side of the optical fiber F can be grasped.

[0086] As described above, in the fusion splicer according to this modification, the position recognition unit 20 recognizes the position of the optical fiber F in the image among the images M31, M32, and M33 in which the difference in brightness between two pixels X1 aligned along the movement direction (X-axis direction) of the optical fiber F is greatest, for each pixel X1 aligned in the direction perpendicular to the movement direction (Z-axis direction). Therefore, even if the shape of the side surface of the optical fiber F is complex, the position of the side surface can be measured in detail. Therefore, the fusion splicer according to this modification can achieve the same effects as the fusion splicers according to FIGS. 13 and 14 .

[0087] The above describes 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 spirit and scope of the claims. The shape, size, number, materials, 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 spirit and scope of the claims. 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 spirit and scope of the claims. A fusion splicer or fusion splicing method may be a combination of multiple aspects of the above-described embodiments and various modifications.

[0088] For example, in the above-described embodiment, an example was described in which the driver 14 was a stepping motor, and the fixed distance, which is the amount of movement of the optical fiber F by the driver 14 per movement, was 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 driver 14 moves the optical fiber F by one pulse, or the microscope 15 may image the optical fiber F every time the driver 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 driver 14 moves the optical fiber F by one pulse. Furthermore, the driver may be something other than a stepping motor, and the type of driver is not particularly limited.

[0089] 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...Image capture 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, M21, M22, M23, M24, M31, M32, M33, M34...Image P...Position X, X1, X2, X3, X11, X12, X13, X14, X15, X21, X22, X23, X24, X25, X26,

Claims

1. a stand on which the optical fiber is placed; a drive unit that moves the table; 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 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 predetermined distance; the position recognition unit recognizes the position of the surface of the optical fiber moved by the drive unit from the plurality of luminances of the plurality of images obtained by the microscope. Fusion splicer.

2. 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 .

3. the position recognition unit recognizes, as the reference position, the position of the surface of the optical fiber in the image in which a difference in luminance between two of the pixels aligned along the moving direction of the optical fiber is maximum among the plurality of images; 3. The fusion splicer of claim 2.

4. the position recognition unit stores a moving distance of the optical fiber from the reference position, and recognizes the position of the surface by adding the moving distance of the optical fiber from the reference position to the reference position.

3. The fusion splicer of claim 2.

5. the position recognition unit stores the number of times the optical fiber has moved the certain 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 certain distance as the moving distance to the reference position.

5. The fusion splicer of claim 4.

6. the position recognition unit recognizes the position of the surface of the optical fiber in an image among the plurality of images in which a difference in brightness between two of the pixels aligned along the moving direction of the optical fiber is maximum, for each of the pixels aligned in a direction perpendicular to the moving direction; The fusion splicer of claim 1 .

7. the position recognition unit stores the number of times the optical fiber has moved the certain distance, and recognizes the position of the surface by subtracting the product of the number of times the optical fiber has moved and the certain distance from the position of the surface of the optical fiber in the image where the brightness difference is maximum.

7. The fusion splicer of claim 6.

8. the position recognition unit recognizes the position of the surface for each of the pixels aligned in a direction perpendicular to the movement direction.

7. The fusion splicer of claim 6.

9. the driving unit moves the optical fiber along the longitudinal direction of the optical fiber; The fusion splicer according to any one of claims 1 to 8.

10. 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 8.

11. The certain distance is equal to or less than half the pixel size. The fusion splicer according to any one of claims 1 to 8.

12. 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.

13. the surface is a side surface of the optical fiber extending along the longitudinal direction of the optical fiber; The fusion splicer according to any one of claims 1 to 8.

14. 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 8.

15. the image processing unit calculates a luminance difference between two of the pixels aligned along the moving direction of the optical fiber, The position recognition unit stores the luminance difference calculated by the image processing unit.

15. The fusion splicer of claim 14.

16. 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 8.

17. the position recognition unit stores an image captured by the microscope and recognizes the position of the optical fiber from the brightness of each output pixel. The fusion splicer according to any one of claims 1 to 8.

18. the position recognition unit recognizes, as the position of the surface, the position of a 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 8.

19. moving a table on which the optical fiber is placed; imaging the optical fiber; a step of outputting the luminance of the image obtained by the imaging step for each pixel; a step of recognizing a position of the surface of the optical fiber from the brightness 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 the pixel size of the pixel, In the imaging step, an image of the optical fiber is captured every time the optical fiber moves the predetermined distance; In the step of recognizing the position, a position of the surface of the optical fiber that has moved is recognized based on the plurality of luminances of the plurality of images. Fusion splicing method.