JPS6340694A - Forming method for laser light - Google Patents

Abstract

PURPOSE:To optionally form the beam shape of a laser light and the power distribution by making a divided laser light incident on an optical fiber and optionally combining the outgoing end. CONSTITUTION:A laser light 2 is projected to a conical mirror 1 from a laser oscillator and radially reflected with the axial line of the conical mirror 1 as the center. The reflected laser light 2 is progressed into a condenser 4, progressing with performing a multireflection, is converged to one end of an optical fiber 6 by a condensing lens 5 and made incident on the optical fiber 6. The laser light 6 projected from the outgoing end of the optical fiber 6 is projected on the material to be worked as a parallel ray or so as to converge to one point after passing through the lens 7. Consequently the sectional shape of the laser light 2 complied with the shape and characteristic of the material to be worked and a power distribution can be obtd.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a method for forming a laser beam used in material processing, and in particular, to a method for forming a laser beam used in material processing, and in particular to a method for forming a laser beam used in material processing. This invention relates to a method of forming laser light to obtain optimal laser light.

(Prior art) Laser light is generally obtained by using a laser light oscillator, but the power distribution of the laser light is often not uniform, and in order to obtain a uniform power distribution, expensive equipment is required. However, it also has the disadvantage of requiring complicated operations.

The cross-sectional shape of the laser beam obtained from a general laser beam oscillator is circular or rectangular, and the power distribution is often a Gaussian distribution, or a complex multi-mode laser, as shown in Figure 3. The cross section of the light is symmetrical about the center of the laser beam, and the intensity is strongest at the center and decreases as you move away from the center. A light beam with this distribution is called a Gaussian light beam.

Simple methods for obtaining a uniform distribution from a Gaussian laser beam include the beam oscillation method, integrated mirror method, and kaleidoscope method (see Section 7).
(See figures 9 to 9).

The beam oscillation method, as shown in FIG. 7, is a method in which the laser beam 2 is received by a concave mirror 9, the reflected light is irradiated onto a plane N10111 that swings at high speed, and a uniform distribution is obtained from the reflected light. Therefore, the cross-sectional shape of the laser beam 2 obtained is determined by the swing width.The example shown in FIG. 7 is for obtaining a rectangular cross-section.

In the integrated mirror method, as shown in FIG. 8, a large number of small flat mirrors 12 of the same shape are arranged in a parabolic shape so that the reflected light from the mirrors 12 is converged at an arbitrary position, and a laser beam is applied to the concave mirror 13. By irradiating the light 2, a uniform power distribution is obtained.

The kaleidoscope method uses a rectangular cylinder 14 as shown in Figure 9.
The inner circumferential wall of the tube is formed by a plane mirror 15, the laser beam 2 is focused and incident on one end of the tube, and by utilizing multiple reflections by the plane mirror 15, a laser beam having a uniform power distribution is emitted from the other end of the tube 14. It is something that makes you Furthermore, the 8th
In the figure, 16 indicates a lens.

Many other methods and devices for obtaining laser light with uniform or arbitrary power distribution by applying simple optical processing to this Gaussian light beam have been devised, and patent applications have been filed (Japanese Patent Laid-Open Publication No. No. 55-50209, JP-A-60-44
192, see).

For example, in Japanese Patent Application Laid-Open No. 55-50209, a laser beam is divided into two by a mirror made of a triangular prism or the like with the central axis of a Gaussian beam as a boundary, and then the two concave mirrors are each irradiated with the two divided laser beams. The two-split laser beam is focused on the focal point of the concave mirror. Therefore, the laser beam will be damaged at the focal point of the concave mirror), but in an appropriate cross-section of the laser beam at that point, the high-intensity portion and the low-intensity portion in the power distribution overlap, so that #1 is approximately uniform. Get the power distribution.

Furthermore, Japanese Patent Application Laid-open No. 60-44192 discloses a method for obtaining an arbitrary power distribution, in which a laser beam introduced along the rotation axis is commonly irradiated onto each mirror surface of a mirror body having a plurality of mirror surfaces, and the reflected light is reflected. The light is focused on a predetermined position by concave mirrors corresponding to the number of mirror surfaces, thereby forming many power distributions.

Further, by rotating the mirror body and the concave mirror together about the rotation axis, various kinds of power distributions can be formed.

(Problems to be Solved by the Invention) However, the laser beam with the power distribution obtained by the above method cannot be used sufficiently for processing workpieces having complicated shapes with curved surfaces or uneven surfaces. That is, this is because the energy transmission efficiency from the laser beam to the workpiece material is poor.

Beam oscillation method, integrated mirror method,
In the kaleidoscope method, it is difficult to arbitrarily change the power distribution and cross-sectional shape of the laser beam.

The same applies to JP-A No. 55-50209.

Although JP-A No. 60-44192 can accommodate a wide variety of power distributions, it is difficult to arbitrarily form the cross-sectional shape of the laser beam.

(Means to Solve the Problem) In order to solve the above-mentioned problem, this invention splits the laser beam into multiple parts, and then splits the laser beam into a plurality of light beams. This can be achieved by arbitrarily setting the beam shape and power distribution of the laser beam that is incident on the fiber and output from the optical fiber by arbitrarily combining the output ends of the optical fiber.

(Function) According to the above configuration, the split laser beam is made incident on the optical fiber, and the output ends are arbitrarily combined to arbitrarily combine the beam shape and power distribution of the laser beam emitted from the original fiber. It becomes possible to easily obtain the optimal laser beam for the shape of the processed material and for custom orders.

(Example) Hereinafter, an example of the method for forming a laser beam according to the present invention will be described in detail with reference to the drawings.

Reference numeral 1 denotes a conical mirror whose vertical cross-section is formed into a right isosceles triangle with a right angle apex. The cone f#, 1 emits laser light 2 from a laser oscillator (not shown) at 90@
Its axis at coincides with the center of the laser beam 2, and it is installed so that the curved portion faces the laser oscillator. By arranging it like this,
The path of Lenizar light 2 is bent by 90 degrees, and it becomes a circle! The laser beam is reflected radially from the top of Challenge 1.

Reference numeral 3 denotes a beam splitting device, which, as shown in FIG. One! ! The beam splitting device 3 consists of a device main body 5a in the shape of an armature arranged around the conical mirror 1 and a plurality of optical fibers 6. A plurality of conical holes 3b are formed in the device main body 3a. ing. The holes 3b are arranged at regular intervals in the circumferential direction of the device main body 3a, and their bottom faces open to the inner circumferential surface of the device main body 3a, and their axes are directly aligned with the axis t of the conical mirror 1. A condensing mirror 4 is attached to the inner peripheral surface of the hole 3b, and the top of the conical condensing mirror 4 is opened. A lens 5 is installed, and the optical axis of the condenser lens 5 substantially coincides with the central axis of the laser beam 2 reflected by the conical mirror 1, and also substantially coincides with the central axis of the condenser mirror 4.

Reference numeral 6 denotes an optical fiber, the input end of which is inserted into an opening formed at the top of the condenser mirror 4, and the laser beam 2 converged by the condenser lens 5 enters from the input end of the optical fiber 6. The output end of the optical fiber 6 provided with the lens 7 is again apertured with a convex lens and inserted into the insertion hole 8a of the frame 8, which has insertion holes 8a formed according to the number of original fibers 6 that exit as parallel light beams. They are bundled by being inserted into holes. When the optical fibers 6 are bundled in this way, the desired power distribution can be obtained by appropriately combining and arranging the optical fibers 6, and if the optical fibers 6 are arranged as shown in FIG. The laser beam 2 can be shaped into a beam, and by tilting the output end of the optical fiber 6 as shown in FIG. 5, the laser beam 2 can be focused on one point.

Incidentally, instead of providing the lens 7 at the output end of the original fiber 6, the same effect can be obtained by forming the end into a lens shape. Incidentally, Fig. 4 shows an example for obtaining a power distribution suitable for hardening a flat material over a wide range, and Fig. 5 shows an example for obtaining a laser beam with a high energy density.

FIG. 6 is another example of FIG. 5, and 17 indicates a processed lens.

Therefore, the laser beam 2 depending on the shape and characteristics of the material to be processed
The cross-sectional shape and power distribution can be obtained.

18 indicates a workpiece.

Next, a method for forming laser light according to the above configuration will be explained.

A laser beam 2 is transmitted from a laser oscillator (not shown) to a conical mirror 1.
, the laser beam 2 is reflected radially around the axis of the cone 1fJ81. reflected laser light 2
The light beam advances into the condenser mirror 4, where it travels through multiple reflections, is further converged by the condenser lens 5 onto one end of the optical fiber 6, and enters the optical fiber 6. The laser beam 6 emitted from the output end of the optical fiber 6 passes through the lens 7 and then passes through the fourth lens.
The material to be processed is irradiated with parallel light beams in the case shown in the figure, and so as to converge to a single point in the case of FIG.

(Effects of the Invention) As is clear from the above, in the present invention, the laser beam is split and then input into the optical fiber, so that the power distribution and cross-sectional shape of the laser beam can be arbitrarily formed. Therefore, laser light energy can be efficiently irradiated to the workpiece material according to the shape, percentage, and processing purpose of multiple and diverse workpiece materials, which improves work efficiency and widens the effective range of the workpiece. It will expand significantly.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG. 2 is a sectional view showing an embodiment of the present invention.
A detailed view of the beam splitting device shown in FIG. 1, FIG. 3 is an explanatory diagram showing the power distribution in the laser beam of Gaussian light i=M, FIG. 4 is a cross-sectional view of the frame shown in FIG. 1, and FIG. This figure is a sectional view showing another example of the frame shown in FIG. 4. Fig. 6 is a sectional view showing another example of Fig. 5, Fig. 7 is an explanatory drawing showing the beam oscillation method, Fig. 8 is an explanatory drawing showing the integrated mirror method, and Fig. 9 is an explanatory drawing showing the integrated mirror method. It is an explanatory diagram showing a scope method. 2... Laser light... Optical fiber patent applicant Toyota Motor Corporation Figure 1

Claims (1)

[Claims] (1) After dividing the laser beam into a plurality of parts, the divided laser beam is made to enter an optical fiber provided according to the number of divisions, and the beam shape and power distribution of the laser beam emitted from the optical fiber are determined according to the number of divisions. A method for forming laser light, characterized in that the output ends of optical fibers are arbitrarily set by arbitrarily combining them.