JPS5827118A - Irradiating method for laser light - Google Patents

Abstract

PURPOSE:To improve the accuracy of working by making a laser light incident to a slender optical body having a non-solid annular or arbitrary shape thereby emitting the spot of a sharp shape from the other end face and irradiating the same on the work. CONSTITUTION:The laser light 11 released from a laser oscillator 10 transmits through a condenser lens 12 and is made incident to one end face 14 of a transparent pipe 13. The laser light enters a condenser lens 16 from the other end face 15, and is irradiated as an annular spot 18 of an arbitrary size on the work 17. Here, the laser light 11 advances while the laser beam is reflected totally by the wall surface of the pipe 13 and is distributed substantially to the sharp boundary parts of the inside and outside wall surfaces of the pipe 13, by which the sharp annular spot 18 is formed and the work is worked with high accuracy by said spot.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of irradiating a laser beam with a spot matching the shape of a processed part.

For example, when forming a concession-shaped laser spot on a processed part,
Conventionally, as shown in Fig. 1, a laser beam (3) emitted from a laser oscillator (2) toward a workpiece (1) is passed through a condensing spherical lens (4) and a conical lens (5). It was irradiated and a yield-like spot (6) was formed.

However, the intensity distribution of the annularly formed focused light tends to be uneven depending on the intensity distribution of the laser beam pattern incident on the optical system, and the edges of the annular pattern become blurred, resulting in irradiation that deviates from the target irradiation area. The irradiation caused some inconveniences in processing.

This invention was made to solve the above-mentioned disadvantages, and by transmitting laser light through a non-solid annular or arbitrary-shaped elongated optical body, a spot with a clear shape is irradiated onto the workpiece. It was designed to do so.

Hereinafter, based on the drawings showing the embodiments, the laser beam αυ according to the present invention is transmitted through a condensing lens (13, and is focused on one end surface 04 on the light incident side of the 10th floor of a transparent pie made of quartz or the like). It looks like this. The above one end surface Q of the transparent pipe (13)
4) and the other end surface α step on the opposite side are finished to be optically flat. On the other end surface αQ is a condensing lens α for irradiation.
0 is provided, and the annular laser beam αυ emitted from the other end face 0!9 is focused and irradiated onto the workpiece αη by the above-mentioned OQ in the form of an arbitrary-sized beam (QIlG). . In the propagation of the laser beam (11) in the 0th floor of the transparent pipe, the laser beam (11) travels while being totally reflected on the wall of the transparent pipe α, and as it progresses, it enters one end surface α at one point. The laser beam is expanded in the circumferential direction of the transparent pipe (lal) and converted into an annular cross-sectional shape.Therefore, the annular spot 0 barrel is generated by the laser beam 0υ sufficiently at the sharp boundary groove between the inner and outer wall surfaces of the transparent pipe α moat. The transparent pipe has an inner diameter of 4 degrees and an outer diameter of 5 degrees (wall thickness of 0).
．． 5'I3i+), the length of transparent pipe a3I is L
) is 79+xx, an arcuate spot is obtained by cutting out about 1/4 of the annular portion, but if the length is about 100+u, an annular spot can be obtained.

The length L) may be short if the angle of incidence of the laser beam to one end surface α of the laser beam αυ is large, but if the angle of incidence is wide, the condition for total reflection inside the transparent pipe αJ is satisfied. A portion of the incident laser light does not propagate and leaks to the outside, reducing the transmission power. Therefore, it is effective to make the intensity distribution in the light emission pattern from the other end α■ uniform by increasing the length (L).

FIG. 3 shows a second embodiment of the invention, in which parts common to the first embodiment are denoted by the same reference numerals, and their explanation will be omitted. That is, two laser beams (lla) and (llb) emitted from the meat side of the laser oscillator 000 equipped with a sub-resonator are respectively transmitted through two optical fibers 411. (
Transmit the fruit bundles separately to 2G, transparent pipe α□□
The light enters at a symmetrical position on one end surface (14) of □. With this configuration, the incidence points of the laser beam α1) are three, so that the intensity distribution in the circumferential direction of the annular spot can be made uniform even if the length L) is short.

Figure 4 shows a third embodiment of the present invention using a transparent body (211) in which a tubular object is divided into two along the axis as an optical body for regulating the spot shape.An optical fiber (2s, By entering the laser beam from AS, a clear semicircular arc-shaped spot can be obtained, for example, a welded part (2!9
can be formed.

FIG. 5 shows a fourth embodiment of the present invention, in which a conical transparent pipe 06) tapering toward the other end surface from which the laser beam Qυ is emitted is used as an optical body for regulating the spot shape. This conical transparent pipe (end) makes it possible to omit a condensing lens for irradiation.

By the way, the above 1. When the optical body that regulates the spot shape is a tube as shown in the second and fourth embodiments, as shown in FIG. 5) is connected to the laser beam input end of the pipe (4), and the gas generated from the pressurized supply device (2a1) is injected toward the workpiece (c). It can be blown away to prevent it from sticking to the workpiece.The same effect can be obtained by installing a suction device (not shown) instead of the pressure device.Also, as shown in the same figure, a conical transparent pipe ( The inner and outer surfaces of the tube (to) can be protected by coating with a substance (26) having a refractive index lower than that of the pipe material.

As described in detail above, it is possible to obtain a sharp intensity distribution at the peripheral edge of a spot formed in a curved or arcuate shape, without forming an extra heat-affected layer around the area other than the processed area. At the same time, it has become possible to perform high-precision machining. Furthermore, by combining optical fibers, etc., it is possible to form an irradiation spot in any location, and it can be used for welding and drilling.

It was possible to further improve processing efficiency such as cutting and heat treatment. It is clear that the optical system that regulates the irradiation spot may have a cross-sectional shape other than circular, such as an ellipse that regulates the irradiation spot.

[Brief explanation of drawings]

FIG. 1 is a block diagram for explaining the conventional method, and FIGS. 2 to 5 are block diagrams to explain the first to fourth embodiments of this invention, respectively. (LQ+...Laser oscillator Q3...Transparent pipe agent Patent attorney Noriyuki Chika (and 1 other person)

Claims (1)

[Claims] Laser light enters from one end face of an annular or arbitrary-shaped elongated optical body whose both ends are optically flat and has a non-solid cross section, and laser light distributed in the above-mentioned cross-sectional shape is emitted from the other end face. A laser beam irradiation method characterized by: