JPH02137687A - Laser light condensing device - Google Patents

Abstract

PURPOSE:To perform seam weld and laser patterning work in an arbitrary direction at a high speed by providing a beam shaping optical system which deforms a laser beam having a circular cross section to have an elliptic cross section and can rotate around the optical axis. CONSTITUTION:This laser light condensing device is constituted by housing a concave cylindrical lens 10 and convex cylindrical lens 11 in a cylinder 12. A laser beam 2 having a circular cross section is oscillated from a laser oscillator 1. The laser beam 2 having the circular cross section is deformed to have an almost elliptic cross section by means of a beam shaping optical system 13 constituted of the concave and convex cylindrical lenses 10 and 11 housed in the cylinder 12. A work 7 is irradiated with the elliptic laser beam after the laser beam is reflected with a reflecting mirror 4 and condensed through a condensing lens 5 and a condensed light spot welded part 14 is formed. Therefore, seam weld and laser patterning work can be performed in an arbitrary direction at a high speed.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a laser focusing device that irradiates a workpiece with a laser beam to perform laser processing such as cutting and Nl@ contact.

[Conventional technology]

Conventionally, a laser beam emitted from a solid-state laser, such as a YAG laser, has a circular cross section, and the focused spot also has a circular shape. On the other hand, when overlapping and seaming welding metal plates, such as mild steel plates or stainless steel plates with a plate thickness of 0.5 mm, a pulsed YAG laser is commonly used because it can suppress thermal discoloration and thermal distortion to a small level. Figure 3 shows the workpiece placed on the X-Y table.
This is a schematic diagram of a conventional laser focusing device that performs seam welding in the axial direction, in which a laser beam 2 is oscillated from a laser oscillator 1, and the diameter of the laser beam is expanded with an expander lens 3.
The light is reflected by the reflecting mirror 4 and focused by the condensing lens 5 to
A workpiece 7 placed on a Y-table 6 is irradiated with the light to form a circular focused spot weld 8 on the workpiece 7. At this time, the workpiece 7 was moved in the direction of arrow B on the X axis, and a seam weld 9 was formed by overlapping the circular condensed spot welds 8. FIG. 4 is a diagram showing the locus of a circular focused spot welded part by the laser focusing device of FIG. 3. FIG. Pulsed YAG Depending on the number of pulses (times/second) of the laser beam 2 oscillated from the laser oscillator 1 and the table feed speed (mm/second) of the X-Y table 6, the light is focused in a circular shape as shown in FIG. It is necessary to seam weld the spot welds 8 while maintaining the relationship within the range where they overlap with each other.

[Problem to be solved by the invention]

To increase the welding speed, increase the number of pulses of the oscillating laser and increase the feed speed of the The welding speed is determined by the performance limit of the maximum number of oscillation pulses of 1. Therefore, there is a problem that the welding speed cannot be increased above a certain speed simply by adjusting the feed speed of the X-Y table 6. The purpose of the present invention is to provide a laser focusing device that eliminates the problems of the conventional method and can perform seam welding at a welding speed higher than that of the conventional method even when using a laser oscillator that has a performance limit on the maximum number of oscillation pulses. shall be.

[Means for solving the problem] The above object is to transform a laser beam having a circular cross section emitted from a laser oscillator into an elliptical cross section by housing a concave cylindrical lens and a convex cylindrical lens in a container. This is also achieved by a laser focusing device equipped with a beam shaping optical system that is rotatable about the optical axis. [Function] Equipped with a beam shaping optical system that transforms the laser beam into an elliptical cross-section, the elliptical focused spot is applied to the workpiece, making the spot longer and allowing for faster welding. Furthermore, by rotating the beam shaping optical system with respect to the optical axis, the direction of welding can be changed arbitrarily.

【Example】

The present invention will be described in detail below based on the drawings. FIG. 1 is a schematic diagram of a laser focusing device according to an embodiment of the present invention. In FIG. 1, for example, a laser beam 2 oscillated from a pulsed YAG laser oscillator 1 has a circular cross section, but a concave cylindrical lens 10 and a convex cylindrical lens 1
1 is deformed into a substantially elliptical cross section by a beam shaping optical system 13 housed in a cylinder 12, which is a container, reflected by a reflection mirror 4, and condensed by a condensing lens 5. The workpiece 7 is irradiated to form an elliptical focused spot weld 14. When the workpiece 7 placed on the X-Y table 6 is moved in the direction of the arrow along the y-axis, the workpiece 7 is seam welded and a seam weld 15 is formed. FIG. 2 is an enlarged view of the elliptical focused spot welding part 14 produced by the laser condenser shown in FIG. The cylinder 12 of the beam shaping optical system 13 is
are arranged in the direction shown in Figure 1. In addition, when seam welding the workpiece 7 in the Y-axis direction, by rotating the y-axis of the cylinder 12 of the beam shaping optical system 13 by 90' in the X-axis direction, the laser beam can be focused in an elliptical shape. The long axis direction of the spot welded portion 14 is directed toward the Y-axis direction. When the seam welding direction is welded in the middle direction between the Y-axis and the Y-axis, that is, in a direction inclined at 45 degrees from the X-axis direction, the beam forming It is only necessary to rotate the y-axis of the cylinder 12 of the optical system 13 by 45 degrees in the X-axis direction.This invention is applicable not only to seam welding but also to Conductive film (
High-speed processing can also be achieved for laser patterning processing such as TCO film) and A-5 film.

【Effect of the invention】

According to this invention, a concave cylindrical lens and a convex cylindrical lens are housed in a cylinder, and the circular laser beam emitted from the laser oscillator is transformed into an elliptical shape, and is rotatable about the optical axis center. Since the beam shaping optical system is provided, an elongated elliptical focused spot can be obtained, and the major axis direction of the ellipse can be changed in any direction. Therefore, seam welding and laser patterning can be performed in any direction faster than with conventional circular spots.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a laser condensing device according to an embodiment of the present invention, Fig. 2 is a diagram showing the locus of an elliptical focused spot by the laser condensing device of Fig. 1, and Fig. 3 is a diagram according to a conventional example. FIG. 4 is a schematic diagram of a laser condensing device, and is a diagram showing the locus of a circular condensed spot by the laser condensing device of FIG. 3. 1; Laser oscillator, 2; Laser beam, 7: Workpiece,
10: concave cylindrical lens, 11: convex cylindrical lens, 12: cylinder, 13: beam shaping optical system.

Claims (1)

[Claims] 1) A concave cylindrical lens and a convex cylindrical lens are housed in a cylinder, which transforms a laser beam with a circular cross section emitted from a laser oscillator into an elliptical cross section and makes it rotatable about the optical axis center. A laser focusing device characterized by being equipped with a beam shaping optical system.