JPH05150145A - Method for making laser light incident on optical fiber - Google Patents

Abstract

PURPOSE:To obtain the method for making the laser light incident on the optical fiber which decides the optimum position of incidence of the laser light on the optical fiber by easy set-up. CONSTITUTION:A dichroic mirror 8 is installed on the optical path between a laser oscillator 1 and a condenser lens 3 arranged at the incidence terminal side of the optical fiber 2, a TV camera 9 is arranged behind it on the reverse surface side of said dichroic mirror while facing the incidence terminal of the optical fiber, and the incidence terminal of the optical fiber is fitted to a fixed jig 4 mounted on an X-Y-Z moving stage 11. A burn pattern is formed on a photosensitive plate 13 which is set first on the fixed jig, the convergence position and convergence spot diameter of the laser light are verified on the screen of the monitor 10 of the TV camera, and the burn pattern is aligned with a reference point on the monitor screen; and then the moving stage is operated while the core end surface of the optical fiber fitted to the fixed jig is observed on the monitor, thereby performing the optimum positioning and adjustment of the optical fiber incidence terminal for the laser light.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to a laser processing system for transmitting a laser beam oscillated from a laser oscillator to a processing point through the optical fiber, and more particularly to a laser beam incidence method for an optical fiber. The present invention relates to a method of positioning an appropriate laser light incident position.

[0002]

2. Description of the Related Art In recent years, various processing devices using a high-power laser (power output of several tens of W or more) have become widespread.
Since the G laser has an oscillation wavelength of 1.06 μm (invisible light) and a high transmittance to an optical fiber (quartz type), YA
Various laser processing systems in which an optical fiber is combined with a G laser oscillator and laser light oscillated from the laser oscillator is flexibly transmitted to the processing point through the optical fiber with low loss have been put into practical use.

By the way, in order to efficiently transmit the power of the laser light oscillated from the laser oscillator to the optical fiber, a spot where the laser light beam emitted from the laser oscillator is condensed by a condenser lens at the incident end of the optical fiber. Must be accurately positioned and made incident so that is within the range of the core diameter of the optical fiber. And in this case,
The higher the laser output, the more accurate the positioning of the incident laser light is required. That is, in a high-power laser oscillator, the power density of the laser light spot emitted from the oscillator and connected to the focal point of the condenser lens is extremely high. Further, the larger the output of the laser oscillator, the larger the beam divergence angle θ of the laser light. For example, when a YAG laser oscillator having a beam divergence angle of θ = 8 mrad at a laser power of 100 W and θ = 24 mrad at 400 W and a focusing lens of a focal length f = 40 mm is combined, a focused spot diameter d of the laser beam is
_{From the equation} of d ₀ = f × θ, ₀ is 0.32 mm when the laser power is 100 W, and 0.96 mm when the laser power is 400 W.
On the other hand, optical fibers have core diameters of 0.4 mm and 0.6 m depending on the application.
Various specifications of m, 0.8 mm, 1.0 mm are used.

Therefore, if there is a large deviation between the optical axis of the laser beam and the center of the core of the optical fiber with the optical fiber attached to the laser beam emitting side of the laser oscillator,
The focused spot of the light beam protrudes from the end face of the core of the optical fiber, and irradiates the connector holding the incident end of the optical fiber, a fixing jig, and the like to cause heating and damage. Also, if the core end face of the optical fiber shifts from the proper position even in the optical axis direction,
If the defocus amount becomes unnecessarily large and the focused spot does not fit inside the core, or conversely if the laser power is large when the core end face matches the focus of the focusing lens, the core end face will be a laser beam with high power density. May be damaged.

Therefore, conventionally, with respect to an optical fiber combined with a high-output YAG laser oscillator, the laser light incident on the optical fiber is positioned as follows. (1) First, in FIG. 4, 1 is a YAG laser oscillator,
Reference numeral 2 is an optical fiber, 3 is a condenser lens placed on the incident side of the optical fiber 2, and 4 is a fixing jig for holding the incident side end of the optical fiber 2. In the laser oscillator 1, 1a is Y
AG laser rod, 1b is an excitation lamp, 1c is an output mirror, and 1d is a total reflection mirror.

In order for the laser light oscillated by the YAG laser oscillator 1 to be properly incident on the end face of the core of the optical fiber 2, the oscillation wavelength of the YAG laser is invisible light (near infrared light). A He-Ne laser 5 that oscillates red visible light is arranged for alignment with the laser oscillator 1 on the same optical axis as a guide, and the red laser light emitted from the He-Ne laser 5 is directed to the core at the incident end face of the optical fiber 2. While visually confirming irradiation, the fixing jig 4 is finely adjusted in the X-Y axis direction perpendicular to the optical axis and temporarily fixed to the fixing jig, and the optical fiber 2 is roughly positioned. Next, the light receiver 6 is set at the emission side end of the optical fiber 2, and in this state, the YAG laser oscillator 1 is oscillated with a small output to actually transmit the YAG laser light to the optical fiber 2 and transmit it at the emission side. The power of the received laser light is read by the power meter 7 connected to the light receiver 6. Then, in this state, while finely adjusting the position of the fixing jig 4 in the optical axis direction (Z axis), the position where the reading of the power meter 7 is maximized is determined to determine the incident position of the laser light. The entrance end of the optical fiber 2 is set at the position and the fixing jig 4 is completely fixed.

(2) Next, another method of positioning the entrance of the optical fiber different from the above method will be described with reference to FIG. That is, in this method, first, the plastic film 20 is set at the attachment position of the optical fiber 2 at the incident end. Then, the YAG laser oscillator 1 is oscillated, and the plastic film 20 is irradiated with the laser light condensed by the condenser lens 3 to form a hole 2 on the surface thereof.
Open 0a. Further, the same operation is repeated by slightly moving the position of the plastic film 20 in the optical axis direction and changing the irradiation position of the plastic film, and the diameter of the hole 20a formed in the plastic film 20 is smaller than the core diameter of the optical fiber 2. Also determines the position that becomes smaller. next,
The laser oscillator 1 is stopped, and the telescope 21, which is a combination of the visible light mirror 21a, the lens system 21b, and the screen with cross 21c, is installed on the optical path between the laser oscillator 1 and the condenser lens 3, and the plastic film 20 Hole 20
a is observed, and the hole 20a has the cross-shaped screen 21
The field of view and the focus of the telescope 21 are adjusted so as to be in focus at the center point of c. Then, with the telescope 21 fixed at this position, the plastic film 20 is removed and the entrance end of the optical fiber 2 is temporarily fixed at that position by the fixing jig 4, and the optical fiber 2 is observed while observing with the telescope 21. After the position of the optical fiber 2 is finely adjusted and positioned so that the end face of the core is located at the center of the cross-shaped screen 21c and in focus, the entrance end of the optical fiber 2 is fixed by the fixing jig 4. Further, with the telescope 21 removed, the light receiver 6 is set on the emission end side of the optical fiber 2 to oscillate the laser oscillator 1 with a small output as described with reference to FIG. It is confirmed whether the incident position of 2 is proper.

[0008]

By the way, the above-mentioned conventional laser beam incident positioning method has the following drawbacks. That is, as described with reference to FIG. 4, in the method of performing incident positioning using the red visible light emitted from the He-Ne laser as a guide, the optical axis of the YAG laser oscillator (invisible light) and the incident end face of the optical fiber are aligned. Although it can be visually confirmed, its positioning accuracy is rough, and it is impossible to quantitatively grasp the amount of deviation from the core center with respect to the optical axis and the defocus amount with respect to the focused spot. For this reason, a low-power laser with a low output does not pose a serious problem, but a high-power laser has a large effect on a slight positional deviation of the optical fiber. is there.

Further, in the method using the plastic film described in FIG. 5, the work of punching the plastic film is repeated many times until the optimum incident position is determined, and on the optical path through which the laser light passes. A large amount of setup work and time are required to position the entrance end of the optical fiber, such as setup work for setting the telescope. Moreover, the diameter of the hole that is made by irradiating the laser beam on the plastic film surface does not necessarily match the diameter of the focused spot of the laser beam, and the hole diameter also varies depending on the laser output. Therefore, although higher incident positioning accuracy can be obtained as compared with the method of FIG. 4, there is a functional problem in that the optimum incident positioning cannot be quantitatively confirmed.

The present invention has been made in view of the above points, and an object thereof is to eliminate the drawbacks of the conventional method, to quantitatively grasp the optimum incident positioning of the laser beam to the optical fiber, and to perform the simple setup. An object of the present invention is to provide a method of injecting laser light into an optical fiber which can be realized with high accuracy and which is particularly suitable for a high-power laser oscillator.

[0011]

According to the present invention, the above object is to install a dichroic mirror on an optical path between a laser oscillator and an incident end of an optical fiber, and to direct the dichroic mirror toward the incident end of the optical fiber. A TV camera is placed on the back side, the laser beam focusing position and the focusing spot diameter are verified on the monitor screen of the TV camera, and the core end face position of the optical fiber incident end with respect to the laser beam is confirmed. It is achieved by adjusting the positioning of the entrance end of the optical fiber.

Further, there are the following embodiments as means for supporting the above method. (1) A fixing jig that holds the entrance end of the optical fiber, and a moving stage that moves and adjusts the fixing jig in the three-axis directions of XYZ with respect to the optical axis of the laser light, and includes a fixing jig. While confirming the core end face position of the optical fiber attached to the tool via the connector on the monitor screen of the TV camera, the movable stage is operated to position and adjust the incident end of the optical fiber to an appropriate incident position.

(2) A photosensitive plate, which receives a laser beam and forms a trace of a focused spot, is set on the jig for fixing the optical fiber mounted on the moving stage of the above (1), and the laser oscillator is used. The trace of the focused spot formed on the photosensitive plate by the oscillated laser light is projected on the monitor screen of the TV camera to verify the focused position of the laser light and the focused spot diameter. Also, as the photosensitive plate used here,
A solar cell substrate having a light-absorbing thin film formed on a glass substrate is preferably used.

(3) A pattern recognition device for detecting the deviation amount and the deviation direction between the center of the end face of the optical fiber and the laser focusing position on the monitor screen of the TV camera is provided, and a command from the pattern recognition device is provided. Based on this, the moving stage is operated to automatically correct the incident end position of the optical fiber. (4) A laser equipped with a power meter that detects leaked light from the dichroic mirror and converts the output power of the laser oscillator from the intensity of the leaked light, and a power controller that links the power meter and the power supply of the laser oscillator. When the output power of the oscillator exceeds the upper limit value corresponding to the core diameter of the optical fiber, the oscillation of the laser oscillator is stopped by a command from the power controller.

[0015]

In the laser beam incident method described above, first, the dichroic mirror is a reflecting mirror consisting of a number of thin tanks with different refractive indexes, which reflects only light of a specific wavelength and transmits all light of other wavelength regions. Have the property to Therefore, the wavelength of the selectively reflected light is set to, for example, the oscillation wavelength of the YAG laser (1.06μ
By disposing a dichroic mirror adapted to m) between the YAG laser oscillator and the incident end of the optical fiber,
The laser light oscillated from the AG laser oscillator is reflected by the dichroic mirror and travels toward the incident end of the optical fiber.
In addition, the TV camera installed on the opposite side of the incident end of the optical fiber with the dichroic mirror interposed allows the incident end of the optical fiber to be projected from the outside of the optical path of the laser light on the monitor screen of the TV camera through the dichroic mirror. You can observe freely.

Then, the core end face of the optical fiber entrance end is aligned with the position of the focused spot of the laser beam emitted from the laser oscillator and focused through the focusing lens, and the focused spot is set within the core diameter. The procedure for positioning the incident light on is performed as follows. (1) First, a photosensitive plate (for example, a solar cell substrate) is placed on the optical fiber fixing jig mounted on the moving stage, and the photosensitive plate is irradiated with laser light emitted from a laser oscillator. As a result, a trace (burn pattern) corresponding to the spot diameter of the irradiation spot is formed on the photosensitive plate. In the solar cell substrate, the thin film on the glass substrate absorbs the laser light and instantly evaporates, and a burn pattern corresponding to the irradiation spot diameter is formed in this portion. Next, TV
Enlarge and display the burn pattern on the monitor screen with the camera, and then fine-tune the TV camera so that the burn pattern is in focus at the center of the cross cross reference line (with scales) on the monitor screen. In this condition, measure the burn pattern diameter on the monitor screen. If the spot diameter of the burn pattern is larger than the core diameter of the optical fiber, the movable stage is operated to position the fixing jig on which the photosensitive plate is placed in the optical axis (Z axis) direction of the laser light. Move slightly,
Repeat the same operation as above to verify it on the monitor screen, and finally determine the exact position of the fixing jig so that the spot size of the laser beam irradiated on the photosensitive plate is within the core diameter of the optical fiber. ..

(2) Next, while holding the TV camera in the above state, the photosensitive plate is removed from the fixing jig, and the incident end of the optical fiber is arranged so that the end face of the optical fiber is aligned with the photosensitive plate. Is fixed, and the end face of the core is projected on the monitor screen through the TV camera. Then, the moving stage is finely adjusted in the X- and Y-axis directions so that the image of the core end face is located at the center of the cross line on the monitor screen, and the appropriate incident end position of the optical fiber is positioned. In this case, if the TV camera has a magnification of, for example, 50 times, the core of the optical fiber having a core diameter of 0.8 mm is enlarged to 40 mm and is projected on the monitor screen. If a 1 mm unit scale is attached, the observation accuracy of the unit scale on the monitor screen will be 0.02 mm.

(3) When the laser oscillator is oscillated with the incident end of the optical fiber positioned and fixed as described above,
The laser light emitted from the oscillator is transmitted through the condenser lens so that the laser light is incident on the optical fiber so that the laser light is contained within the diameter of the end face of the core of the optical fiber. This state can be quantitatively confirmed by setting a light receiver on the emission end side of the optical fiber and measuring the power of the transmitted laser light.

On the other hand, on the monitor screen of the TV camera, there is provided a pattern recognition device for detecting the deviation amount and the deviation direction between the center of the end face of the optical fiber and the laser focusing position, and based on the command from the pattern recognition device. In the method of operating the moving stage to automatically correct the incident end position of the optical fiber, if the focused spot position and spot diameter of the laser light are verified by the method described in (2) above, it is fixed. After attaching the optical fiber to the jig, optimal incident positioning of the optical fiber and positioning and holding during use will be performed automatically without the need for actual human monitoring on the monitor screen. ..

Further, the power meter for detecting the leaked light from the dichroic mirror and converting the output power of the laser oscillator from the intensity of the leaked light, and the power controller for linking the power meter and the power source of the laser oscillator are provided. If the control method of stopping the oscillation of the laser oscillator by the command from the power controller when the output power of the laser oscillator exceeds the upper limit value corresponding to the core diameter of the optical fiber, the output of the laser oscillator can be widened. When variably adjusted, or when the optical fiber is changed to one with a different core diameter, the laser oscillator is stopped immediately if the laser power and the core diameter do not match.
The trouble that the incident end face of the optical fiber and the connector are accidentally damaged by the laser light during the laser output is avoided.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. In each embodiment, the same parts corresponding to those in FIGS. 4 and 5 are designated by the same reference numerals. Example 1 First, in FIG. 1 (a), a dichroic mirror 8 is arranged on the optical path between the YAG laser oscillator 1 and the condenser lens 3, and the back side of the dichroic mirror 8 is located at the incident end of the optical fiber 2. A TV camera 9 is installed toward the front.
Reference numeral 10 is a monitor connected to the TV camera 9, and reference numeral 10a is a cruciform cross line displayed on the monitor screen. On the other hand, a fixing jig 4 that holds the entrance end of the optical fiber 2
Is attached to the moving stage 11. This moving stage 11 moves the fixing jig 4 to XY with respect to the optical axis of the laser light.
Reference numeral 12 denotes a controller of the moving stage 11, which is operated to move in the three axis directions of -Z.

Further, FIG. 1B shows a state in which a photosensitive plate (for example, a solar cell substrate) 13 for verifying a focused spot of laser light is set on the fixing jig 4, and the photosensitive plate 4 is shown. Is fitted in a recess formed on the upper surface of the fixing jig 4 so that the upper surface is flush with the upper surface of the fixing jig. On the other hand, in FIG. 1C, the optical fiber 2 is attached to the fixing jig 4.
The optical fiber 2 is fixed via the connector 14 attached to the tip of the optical fiber 2 such that the incident end face is flush with the upper face of the fixing jig.

Next, the operation of the method of positioning the entrance end of the optical fiber 2 having the above-described structure at the optimum position will be described step by step. (1) First, the photosensitive plate (for example, a solar cell substrate) 13 is provided on the upper surface of the optical fiber fixing jig 4 mounted on the moving stage 11.
Is set (see FIG. 1B), the laser oscillator 1 is oscillated, and the laser light 15 is irradiated onto the photosensitive plate 13. As a result, the irradiation spot 1 of the laser light 15 is applied to the photosensitive plate 13.
A burn pattern corresponding to the spot diameter of 5a is formed, and the burn pattern can be enlarged and projected as an image on the monitor screen of the TV camera 9. Then, the monitor 10
The TV camera 9 is finely adjusted so that the burn pattern is focused on the center of the cross line 10a, and the diameter of the burn pattern is measured on the monitor 10 screen in this state. If the spot diameter of the burn pattern is larger than the core diameter of the optical fiber 2, the moving stage 11 is moved to Z.
The fine adjustment in the axial direction is repeated and the same operation as described above is repeated, and finally the spot 15a of the laser beam with which the photosensitive plate 13 is irradiated.
Jig 4 whose size is within the core diameter of the optical fiber 2
Determine the exact position of.

(2) Next, the photosensitive plate 13 is removed from the fixing jig 4 while the TV camera 9 is held in the above state,
Instead, as shown in FIG. 1C, the incident end surface of the optical fiber 2 is flush with the upper surface of the fixing jig 4, that is, the photosensitive plate 1 described above.
The incident end of the optical fiber 2 is fixed through the connector 14 so as to be aligned with the upper surface of the optical fiber 3, and the incident end face of the optical fiber 2 is enlarged and projected on the screen of the monitor 10 through the TV camera 9. In this case, a recess is formed in the upper surface of the fixing jig 4 in advance so that the photosensitive plate 13 can be set flush with the upper surface of the jig.
When the is attached together with the connector, the surface of the core end of the optical fiber can be easily aligned so as to be flush with the photosensitive plate.
Then, the moving stage 11 is finely adjusted in the X-Y axis directions so that the image 10b of the optical fiber is located at the center of the cross line 10a on the monitor screen, and the appropriate incident end position of the optical fiber 2 is positioned and set. The cross-shaped cross line 10a on the screen of the monitor 10 and the image 10 of the incident end face of the optical fiber 2 are shown.
The amount of deviation from b can be quantitatively grasped by reading the dimensional scale of the cross line 10a. Therefore, by inputting this amount of deviation into the controller 12 of the moving stage 11, the incident position of the optical fiber 2 can be determined. Modified as above.

(3) When the laser oscillator 1 is oscillated with the incident end of the optical fiber 2 positioned as described above,
The laser light 15 emitted from the oscillator passes through the condenser lens 3 and is properly incident and transmitted so as to be contained within the diameter of the core end surface of the optical fiber 2. This state can be confirmed by setting the light receiver 7 on the emission end side of the optical fiber 2 and reading the transmitted laser power with the power meter 7.

In the first embodiment, the position of the focused spot of the laser beam and the spot diameter are verified on the monitor screen of the TV camera by using the burner formed by setting the photosensitive plate 13 on the fixing jig 4. Although the method based on the pattern has been described, instead of using the photosensitive plate, the red laser for the guide described in FIG. 4 is directly irradiated onto the incident end surface of the optical fiber 2 attached to the fixing jig 4. It is also possible to do so.

Embodiment 2 FIG. 2 shows an applied embodiment of the present invention which is a further development of Embodiment 1 described above. In this embodiment, a pattern recognition device 16 is additionally provided so as to link the monitor 10 and the controller 12 of the moving stage 11. A light receiver 6 and a power meter 7 are provided behind the dichroic mirror 8, and a power controller 18 is provided so as to link the power meter 7 and the power supply device 17 of the laser oscillator 1.

Here, the pattern recognition device 16 is
Based on the image pattern of the optical fiber 2 projected on the screen of the monitor 10, the shift amount and the shift direction between the center of the core end face and the center of the cross line are detected, and the output thereof is used as a feedback signal to the moving stage 11. give. On the other hand, the light receiver 6 receives the leaked light of the laser light 15 that slightly leaks behind the dichroic mirror 8, and the power meter 7 outputs the light from the light receiver 6 based on the leak characteristics (tested in advance) of the dichroic mirror 8. Is used to convert the actual output power of the laser oscillator 1. Further, the power controller 18 includes the laser power of the laser oscillator 1 and the condenser lens 3
Data showing the relationship with the spot diameter condensed by the above (refer to the above-mentioned [Prior Art]), and the upper limit data of the laser power for each core diameter of the optical fiber (for example, the core diameter is 0.4 mm). If so, the upper limit of the laser power is 100
If W and the core diameter is 1.0 mm, the upper limit of laser power is 4
00W) is stored.

With the above configuration, the focus spot position and spot diameter of the laser beam are verified on the monitor screen of the TV camera 9 in advance by the method described in the first embodiment, and the burn pattern of the focus spot is displayed on the monitor screen. If you set it so that it will be located at the center of the cross, the fixture 4
After the optical fiber 2 is attached to, the pattern recognition device 16 finely adjusts the moving stage 11 to automatically correct the incident end position of the optical fiber 2. Therefore, the optimum incident position of the optical fiber can be measured without relying on manual monitoring and operation.
In addition, positioning and holding during use can be performed automatically.

Further, when the output of the laser oscillator 1 is variably adjusted over a wide range, or when the optical fiber 2 is replaced with one having a different core diameter, the laser power oscillated from the laser oscillator 1 and the core diameter of the optical fiber 2 are changed. If and do not match, the power controller 18 immediately outputs an oscillation stop command to the power supply device 17 of the laser oscillator 1. As a result, the trouble that the incident end face of the optical fiber and the connector are accidentally damaged by the laser light during the laser output is avoided.

Embodiment 3 FIGS. 3 (a) and 3 (b) show an application system in which laser light emitted from a laser oscillator is switched to a plurality of optical fibers in the middle of an optical path or is branched and transmitted. It shows an example. Here, FIG.
(A) is a case where the laser light 15 emitted from the laser oscillator 1 is switched to and transmitted by the two optical fibers 2 arranged side by side, and the dichroic mirror 8 is installed so as to be movable left and right in accordance with the position of each optical fiber. In addition, a TV camera 9 is provided behind the dichroic mirror 8 for each optical fiber 2. When the laser light 15 emitted from the laser oscillator 1 is incident on the optical fiber 2 on the left side, the dichroic mirror 8 is set to the solid line position in the figure, and in this state, the optimum incident position of the optical fiber 2 is determined by the method described above. To do. When the right optical fiber 2 is used, the dichroic mirror 8 is moved to the dotted line position in the figure, and the optical fiber 2 is positioned in this state.

On the other hand, FIG. 3B shows a case in which the laser light 15 emitted from the laser oscillator 1 is split and made incident on two optical fibers 2 at the same time. Beam splitter 1 corresponding to each optical fiber 2
9 and the dichroic mirror 8 are installed, and the beam splitter 19 and the dichroic mirror 8 are further installed.
A TV camera 9 is installed behind each of them, and in this configuration, the laser beam 15 is incident and positioned on each optical fiber 2 in the same manner as described above.

In the above embodiment, the YAG laser is used as the laser oscillator, but it is of course applicable to other laser oscillators as long as the laser transmission to the optical fiber is possible. ..

[0034]

As described above, the method of making a laser beam incident on an optical fiber according to the present invention has the following effects. (1) First, by adopting the method according to claim 1 of the present invention, the incident end face of the optical fiber arranged on the laser optical path is passed through the dichroic mirror from the outside of the optical path of the laser light to the T
It is possible to accurately position the incident end of the optical fiber at an optimum position by observing on the monitor screen of the V camera and quantitatively grasping the shift amount of the optical fiber and the like. Moreover, T
Since the V camera is installed outside the laser optical path, the incident position of the optical fiber can be monitored without any special setup work even during the use of the system in which the laser light oscillated by the laser oscillator is transmitted by the optical fiber. In addition to the correction operation, even if the optical fiber is replaced on the way, incident positioning can be performed in a short time after the replacement of the optical fiber, which requires some setup work.

(2) Further, by adopting the movable stage according to the second aspect of the present invention, it is possible to adjust the incident positioning of the optical fiber while fixing the fixing jig through the connector. (3) Further, as a means for verifying the position and spot diameter of the focused spot of the laser light, the movable stage is used to set the photosensitive plate here, as in claims 3 and 4 of the present invention. , Verification work can be done easily and efficiently. In particular, since the solar cell substrate used as the photosensitive plate has high dimensions and flatness of the glass substrate, it is easy to verify the burn pattern, and it is also convenient for the surface alignment with the fixing jig and the core end face of the optical fiber.

(4) On the other hand, by adopting the automatic correction means according to claim 5 of the present invention, it is not necessary to monitor the monitor screen with human eyes, and the initial incidence positioning to the optical fiber and the correction during use are performed. Can be done automatically. (5) Further, by adopting the control means according to claim 6 of the present invention, when the output power of the laser oscillator is variably adjusted over a wide range during use, or the optical fiber is changed to one having a different core diameter during the adjustment. Even if the laser power and the core diameter of the optical fiber do not match, the oscillation of the laser oscillator is immediately stopped and controlled, so the end face of the optical fiber and the connector are unexpectedly damaged by the irradiation of laser light with high power density. Since it is possible to avoid doing this, safety is enhanced.

[Brief description of drawings]

1A and 1B are configuration diagrams of a system corresponding to a first embodiment of the present invention, in which FIG. 1A is an overall system diagram, FIG. 1B is a state diagram in which a photosensitive plate is set on a fixing jig, and FIG. Diagram showing the entrance of the optical fiber attached to the tool

FIG. 2 is a configuration diagram of a system corresponding to a second embodiment of the present invention.

3A and 3B are configuration diagrams of a system corresponding to Example 3 of the present invention, in which FIG. 3A is a configuration diagram in the case where laser light emitted from a laser oscillator is switched to be incident on two optical fibers, and FIG. Configuration diagram when laser light emitted from a laser oscillator is split and simultaneously incident on two optical fibers

FIG. 4 is a configuration diagram of a system showing a conventional optical fiber entrance positioning method.

5 is a configuration diagram of a system showing an optical fiber entrance positioning method different from FIG.

[Explanation of symbols]

 1 YAG laser oscillator 2 Optical fiber 3 Focusing lens 4 Fixing jig for optical fiber 8 Dichroic mirror 9 TV camera 10 Monitor 11 Moving stage 13 Photosensitive plate 14 Optical fiber connector 15 Lens light 15a Focusing spot 16 Pattern recognition device 17 Laser Power supply for oscillator 18 Power controller

Claims (6)

[Claims] 1. A laser beam incidence method for accurately injecting a laser beam oscillated from a laser oscillator to a core end face of an optical fiber through a condenser lens, which is a light beam between the laser oscillator and an incident end of the optical fiber. A dichroic mirror is installed on the road, and a TV camera is arranged on the back side of the dichroic mirror toward the incident end of the optical fiber, and the focus position of the laser beam and the focus spot diameter of the laser beam are monitored on the monitor screen of the TV camera. A method for injecting laser light into an optical fiber, which comprises performing verification and confirming the position of the core end surface of the optical fiber incident end with respect to the laser light, and adjusting the positioning of the incident end of the optical fiber based on this. 2. The laser beam incident method according to claim 1, wherein a fixing jig for holding the incident end of the optical fiber, and the fixing jig are three axes of XYZ with respect to the optical axis of the laser light. The moving stage is equipped with a moving stage for moving and adjusting in the direction, and the moving stage is operated while checking the core end face position of the optical fiber attached to the fixing jig via the connector on the monitor screen of the TV camera. A method for injecting laser light into an optical fiber, wherein the laser beam is positioned and adjusted to an appropriate incident position. 3. The laser beam incident method according to claim 2, wherein a photosensitive plate which receives the laser beam irradiation and forms a trace of a focused spot is set on the fixing jig, and the laser beam oscillated from the laser oscillator is set. Laser light incident on an optical fiber, characterized in that the trace of the focused spot formed on the photosensitive plate is projected on the monitor screen of the TV camera to verify the focused position of the laser beam and the focused spot diameter. Method. 4. The method for injecting laser light into an optical fiber according to claim 3, wherein the photosensitive plate is a solar cell substrate having a light-absorbing thin film formed on a glass substrate. 5. The pattern recognition device according to claim 2, wherein a deviation amount and a deviation direction between the center of the end face of the optical fiber and the laser focusing position are detected on the monitor screen of the TV camera. A method of injecting laser light into an optical fiber, comprising: operating a moving stage based on a command from the pattern recognition device to automatically correct an incident end position of the optical fiber. 6. The laser light incident method according to claim 1, wherein a leak light from the dichroic mirror is detected and the output power of the laser oscillator is converted from the leak light intensity, and a power meter of the power meter and the laser oscillator. A power controller is provided that links with a power supply, and when the output power of the laser oscillator exceeds an upper limit value corresponding to the core diameter of the optical fiber, the oscillation of the laser oscillator is stopped by a command from the power controller. Laser light incidence method for optical fiber.