JPS6316893A - Ring mode forming device - Google Patents

Abstract

PURPOSE:To form a uniform ring mode on a laser beam by providing two condensing lenses at the inlet port side and outlet port side of a scope and making its optical axis concident with the center axis in the longitudinal direc tion of the scope. CONSTITUTION:A laser beam 4 is passed through a condensing lens 2 and projected into the scope 1 subjected to a mirror finish. The laser beam 4 is then conformed with its multireflection by a cylinder 1a and cone shaped mirror 1and forms an uniform ring mode 5 at the outlet port of the scope 1. The laser beam 4 passes a condensing lens 3, forming a ring mode 5 on the work face. With this device, an uniform rectangular heat source can be formed with the multireflection and composition inside the scope 1 of the beam even in the case of the beam of prior to the forming being uneven, and the stability of the formed beam becomes better.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a device that shapes the mode (energy distribution) of a laser beam into a ring shape, and is particularly suitable for use in laser processing such as hardening. It is.

(Prior Art) Conventionally, there is a method that uses a so-called unstable resonator as shown in FIG. 3 to create a ring-shaped laser beam mode. The figure shows the configuration of the internal mirror of the laser oscillator, where a shows a concave mirror, b shows a hollow reflecting mirror, C shows a convex mirror, and d shows a ring-shaped beam mode.

Furthermore, as shown in FIG. 4, there is also a system in which an eccentric axially tilted mirror is rotated at high speed to form an apparent ring mode. In the figure, e is a bender mirror, f is a motor, g is an axially tilted mirror system, h is a laser beam, and i is a ring mode.

(Problems to be Solved by the Invention) In the case of using an unstable resonator as shown in FIG. 3, the obtained beam mode lacks stability and uniformity of energy distribution.

It is necessary to use a beam integrator such as a segment mirror, which makes it extremely difficult to use for surface treatments such as hardening, and the special oscillator structure causes high equipment costs. are doing.

In addition, by rotating an eccentric mirror as shown in Figure 4 at high speed,
Products that mold an apparent ring mode lack the stability of the molding mode because they have a motor drive unit.

■It is difficult to set the beam size. ■The quality of a shaped beam is determined by the quality of the beam before shaping, and if the mode of the beam before shaping is non-uniform, the shaped beam will also be non-uniform. ”
There are problems like this.

(Means and effects for solving the problem) This invention has the following features:
In view of the above problems, we created a scope by attaching mirror-finished cone-shaped mirrors concentrically to the mirror-finished cylindrical inner surface, and placed the scope between two condensing lenses on the central axis of the lens. The central axis of the scope in the cylindrical direction is positioned above the scope, and a focused laser beam is irradiated into the scope from the scope entrance, multiple reflections are made within the scope, and the lights are combined to produce a uniform beam at the scope exit. The ring mode was shaped to obtain a beam mode with stable and uniform energy distribution.

(Example) Next, embodiments of the invention will be described based on the drawings.

Figure 1 + al is an embodiment of the ring mode molding device according to the present invention, 1 is a scope which has a cylindrical shape, and Figure 1 (b
As shown in FIG. 1, a mirror-finished cone-shaped mirror 1b is mounted concentrically within the mirror-finished cylinder Ia. 2 is a condensing lens provided on the entrance side of the cylindrical scope 1, and 3 is a condensing lens also provided on the exit side, and the center of the optical axis of these condensing lenses 2.3 is on the central axis of the cylinder of the scope. It is arranged like this. 4 is a laser beam.

5 is a shaped beam (see FIG. 1(C)).

The focused laser beam is irradiated into a mirror-finished scope, undergoes multiple reflections within the scope, and is combined into a single beam to form a uniform ring mode at the exit of the scope.

In this way, even if the beam before forming is non-uniform,
A uniform rectangular heat source can be formed by multiple reflections and combinations, and since there is no driving part, the stability of the formed beam is improved. Furthermore, the beam size can be set freely, allowing flexible laser processing.

Furthermore, Fig. 2 shows laser hardening of the sheet surface in ring mode as an application of this device. In the case of laser hardening a cylindrical sheet surface in this way 1 For example, in conventional methods such as moving hardening using a spot beam, a softened layer (joint) occurs at the end of the hardening, but as in this invention, irradiation heating is performed using a ring mode. Then.

Sound hardening without a softened layer is possible.

(Effect of the invention) This invention is constructed as described above in detail.

Even if the beam before forming is non-uniform, the beam can be formed into a uniform rectangular heat source by irradiating it into a mirror-finished scope, multiple reflections within the scope, and combining the two beams, and since there is no drive unit installed, it is possible to form a uniform rectangular heat source. Good beam stability. Furthermore, since the beam size can be set freely, flexible laser processing is possible, and it is particularly suitable for use in hardening.

[Brief explanation of the drawing]

FIG. 1(a) shows a ring mode forming device according to an embodiment of the present invention, FIG. 1(bl shows a scope, and FIG. 1(c) shows a forming beam. FIG. Diagrammatic representation of laser hardening. Figures 3 and 4.
The figures each show two examples of conventional devices. 1...Scope, Ia...Cylinder. 1b... Cone-shaped mirror, 2... Condensing lens. 3...Condensing lens. Patent Applicant Komatsu Ltd. Agent (Patent Attorney) Osamu Matsuzawa Figure 1 (b) Figure 1 (C) Figure 2

Claims (1)

[Claims] A scope is formed by concentrically attaching mirror-finished cone-shaped mirrors to the mirror-finished inner surface of a cylindrical cylinder, and condenser lenses are installed at the entrance and exit sides of the scope so that their optical axes coincide with the longitudinal central axis of the scope. A ring mode forming device characterized in that they are arranged so as to match.