JPS60121095A - Device for monitoring working position for laser working machine - Google Patents

Abstract

PURPOSE:To monitor exactly a laser working position and to improve safety by disposing plural optical fibers in parallel in tight contact with the outside circumference of an optical fiber for emission of a laser beam and transmitting illuminating light for monitoring through said fibers. CONSTITUTION:Plural optical fibers OF are disposed in parallel around a fiber WFL for emission of a laser beam in tight contact therewith to form an image bundle fiber IBF. The laser beam for welding passes through the fiber WFL and is emitted via a lens system LNS to a welding surface WL. The irradiation light from a light source LT passes through a half mirror HMR and an image bundle fiber IBF, is restricted by the lens system LNS and is irradiated as parallel beams to the welding surface WL. The reflected image thereof is received by a television camera TVC at the other end of the fiber IBF and can be monitored with a monitor device MNT. Since the naked eyes are not directly exposed to the laser light, safety is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to a monitoring device that has a simple configuration and can accurately observe the processing position by a laser processing machine without looking directly at it.

(2) Prior Art and Problems When sealing the package of a semiconductor component using a laser beam (such as a YAG laser), it is necessary to accurately observe the welding position if the welding target is small. If the laser can be brought close to the welding target, a lens is placed between the laser emitting end and the welding target to narrow down the laser beam and irradiate it. In this case, a TV camera can be placed on the side for monitoring. However, in fiber-emitting processing machines that use '/AG lasers, it is necessary to visually confirm where the laser beam hits the welding target, and the wavelength of the laser beam is close to visible light, which poses a safety issue. It is. A YAG laser is a laser that uses excitation light emitted from yttrium, aluminum, or garnet ronds. When the object is small, the laser beam is focused and irradiated, making it difficult to enlarge the object and observe the irradiation position accurately.

FIG. 1 is a schematic diagram showing a conventional YAG laser welding monitor, where YAG is a YAG laser rond and shows the main parts for laser beam oscillation. Helium as a visible light laser
Add a neon laser (He-Ne) to the optical system C
put. Start the welding work by oscillating the YAG laser
A helium neon laser is oscillated, and the oscillated light from both lasers is once focused by a lens system LNS and irradiated onto the welding part WL through an optical fiber OFF. MR indicates a reflecting mirror.

At this time, the position where the helium neon laser is irradiated on the welding part WL is confirmed with the naked eye. If the reflected light of the e-Ne laser beam is strong, there is a safety problem, and it is difficult to observe the welding position accurately.

Another drawback was that the optical system was complicated.

(3) Purpose of the Invention The purpose of the present invention is to improve the above-mentioned drawbacks and to transmit visible light using an image bundle fiber.
It is an object of the present invention to provide a monitoring device that can observe the position of processing such as welding with sufficient accuracy.

(4) Structure of the Invention A composite fiber is composed of a laser beam emitting fiber at the center and an image bundle fiber in which a plurality of optical fibers are closely arranged in parallel around the outer periphery, and the fiber is brought close to the laser processing section. The laser beam emitting fiber transmits the processing laser light, the image bundle fiber transmits the monitoring illumination light, and the processing position is monitored by a television camera at the other end of the processing section of the image bundle fiber.

(5) Embodiments of the Invention An embodiment of the invention will be described as a welding operation with reference to the drawings shown in FIG. 2 and subsequent figures. Figure 2 shows the composite fiber used in the present invention, and the welded part laser beam emitting fiber WLF
The image bundle fiber IBF is formed by arranging a plurality of optical fibers OF close to each other and parallel to the laser beam emitting fiber WLF around the center. FIG. 3 shows a specific configuration diagram of the first embodiment of the present invention.

The laser beam for welding parts that uses YAG rods is
The light proceeds to the left through the fiber WLF, is focused through the lens system LNS, and is emitted to the welding part WL. On the other hand, the irradiated light from the light source LT of white light reaches the lens system LNS via the image bundle fiber IBF by the half mirror HMR. The irradiated light is once narrowed down by the lens system LNS, and then irradiated onto the welding portion WL as a parallel beam. Image bundle fiber IBF is half mirror HMR and lens system LNS
In between, a split is made in the optical fiber OF forming the image bundle fiber, and a laser beam output fiber WLF is drawn out through the split. As shown in the figure, the image handle fiber IBF is descending, for example, at right angles to the laser beam output fiber WLF.
When the illumination light from the light sources r, T hits the weld WL, an image of the weld can be obtained at the other end of the weld of the image handle fiber IBF. That is, the position where the laser beam is emitted to weld and the status during welding can be transmitted through the image handle fiber IBF. Therefore, by placing a television camera TVC at that position and guiding the received signal to the monitor device MNT, monitoring can be easily performed at a location away from the welding area.

The above is an explanation of monitoring the condition of the weld WL, but since the irradiation position of the weld beam is not clear, FIG. 4 shows an improvement in this respect. In the second embodiment shown in FIG. 4, BL is a black part (a black spot small enough to identify the center point of the welding beam output part) and is located at the center of the fiber at the other end of the image bundle fiber IBF, or Half mirror - Install it in the center of HMR. At this time, since the white light from the illumination light source LT cannot pass through the black part BL, when observed with the monitor MNT, the dark part in the image can be determined to be the weld part.

Further, FIG. 5 shows another embodiment of the present invention in which a second half mirror HMR2 is added between the YAG laser and the composite fiber IBF. The second half mirror HMR2 allows the emitted light of the YAG laser to pass through and guides it to the composite fiber IBF.

The light from the white light source LT for illumination is transmitted through the first half mirror-HM.
After being reflected by R1 and the second half mirror HMR2, it is guided to the composite fiber IBF. At this time, the composite fiber IBF
In the laser beam fiber WLF inside, the laser beam and the illumination light from the light source LT coexist; and in the optical fiber OF part of the composite fiber, the light from the light source LT is both transmitted to the welding part WL. . The image of the weld W+- is transmitted in the opposite direction to the illumination, passes through the first half mirror HMR1, and is received by the television camera 'rvc.

Even if the illumination light passes through the welding laser beam fiber WLF, there is a large difference in the amount of light compared to the illumination light that passes through the image handle fiber IBF. You can see where it is dark. Therefore, you can monitor that location as a welding position.

Of course, the laser beam can be applied to processing operations such as cutting in addition to welding.

(6) Effects of the Invention In this way, according to the present invention, the illumination light beam is transmitted by the image bundle fiber, and the location to be laser processed can be accurately monitored. It is highly safe because the laser beam cannot be seen directly with the naked eye.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing a conventional welding monitor for YAG lasers, Fig. 2 is a perspective view of a composite fiber used in the present invention, and Fig. 3 is a specific configuration of the first embodiment of the present invention. FIG. 4 is a partial diagram of a second embodiment of the present invention, and FIG. 5 is a diagram showing a configuration of another embodiment of the present invention. Y A G---Roso FOP F for Yag Laser
---------Optical fiber wr, ---------One welding surface WLF-----Laser beam output fiber I
B F-----Image bundle fiber L T--
-----------Single white light source TV C-----Television camera M N
T-------Monitor device patent applicant Fujitsu Co., Ltd. agent Patent attorney Eisuke Suzuki

Claims (1)

[Claims] A composite fiber is composed of a laser beam emitting fiber at the center and an image handle fiber in which a plurality of optical fibers are closely arranged in parallel around the outer periphery, and the fiber is brought close to the laser processing section to form a laser beam emitting fiber. A processing position monitoring device for a laser processing machine, characterized in that transmits a processing laser beam, an image bundle fiber transmits a monitoring illumination light, and monitors the processing position with a television camera at the other end of the processing section of the image handle fiber. .