JP2003001471A - Laser beam machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser beam machine which machines a metallic sheet to the smooth peripheral edge of a machined section with high accuracy and to provide a light intensity distribution uniformizing element which is high in accuracy and is simple. SOLUTION: This laser beam machine includes a laser beam source 1, the light intensity distribution uniformizing means 2 and optical means 3. The optical means deflects the laser beam L1 emitted from the laser beam source and focuses the laser beam at the prescribed position of a workplace 10. The laser beam machines the workpiece. Therefore, the refractive index of the core of the light intensity distribution uniformizing element is uniform. Accordingly, the accuracy is high and the circumferential edge of the machined section is smooth.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser beam machine, and more particularly, to a laser beam machine for cutting, punching, engraving, etc. a metal plate or a polymer resin plate.

[0002]

2. Description of the Related Art In recent years, a laser is used to form a circular hole when a stencil metal mask is manufactured by processing a metal plate. It is possible to easily perforate the laser beam by narrowing it into a beam having a constant diameter and burning it into a circular shape having a predetermined diameter. However, the roundness of the obtained hole was low, and the peripheral edge of the hole was not obtained smoothly. Therefore, a mechanism for rotating the laser beam around the optical axis is provided to improve the roundness or smoothness of the hole, but it is not sufficient yet, and it is not sufficient for the formation of the minute hole. .

The inventor of the present application has filed a patent application 2001-12521.
4, a laser light source, an optical means, and a rotating means are provided, the optical means deflects the laser light emitted from the laser light source to focus it on a predetermined position of the workpiece, and the rotating means is the optical means. A technique has been disclosed in which a laser beam perforates a circular hole having a variable diameter by rotating a laser beam and deflecting a deflectable reflecting mirror. As a result, it has become possible to form a circular hole having a higher roundness and a smoother peripheral edge than ever before.

[0004]

However, there remains a problem that the roundness and the smoothness of the peripheral edge of the circular hole formed in the metal plate by the above disclosed laser beam machine are still insufficient. . As a result of intensive research to solve this problem, it was found that if the uniformity of the intensity distribution of the laser light is improved, the roundness of the circular hole and the smoothness of the peripheral edge are improved.
The homogenization of the intensity distribution of the laser light can be achieved by using a two-dimensional microlens array called a beam homogenizer, but it is expensive and large in size and cannot be practically used.
Further, there is a problem that it is not practical to cut off a part of the light flux with an aperture because it causes a large loss of the light amount.

In view of the above problems, the present invention provides a light intensity homogenizing element that easily homogenizes the intensity distribution of laser light,
Further, it is an object of the present invention to provide a laser processing machine which uses this and has a high accuracy and which smoothly processes a metal plate at the periphery of a processed portion.

[0006]

The present invention comprises a laser light source, a light intensity equalizing means, and an optical means, wherein the light intensity equalizing means emits a light beam of a laser beam emitted by the laser light source. The laser processing machine is characterized in that the light intensity of the cross section is made uniform, and the optical means focuses the laser light on the workpiece to process the workpiece.

Further, the light intensity equalizing means includes a core,
An optical fiber composed of a clad covering the outer circumference of the core, wherein the refractive index of the core is at least constant in the cross-sectional direction, and the intensity distribution of the light incident from one end is made uniform and the light is emitted from the other end. The laser processing machine according to claim 1 is configured.

Further, in an optical fiber composed of a core and a clad covering the outer periphery of the core, the refractive index of the core is at least constant in the cross-sectional direction, and the intensity distribution of light incident from one end is Is uniformized and emitted from the other end.

[0009]

According to the invention described in claim 1, the light intensity of the cross section of the light flux of the laser light is made uniform, and the laser light is focused on one point of the workpiece after being deflected by the reflecting mirror in a variable deflection angle. Process the work piece. In the invention according to claim 2, the light intensity equalizing means is an optical fiber including a core and a clad covering the outer periphery of the core, and the refractive index of the core is at least in the cross-sectional direction. It is constant, and the intensity distribution of the light incident from one end is made uniform and the light is emitted from the other end. In the invention according to claim 3, the refractive index of the core is constant at least in the cross-sectional direction.

A laser beam machine according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a conceptual diagram of a laser processing machine. The laser 1 is an Nd: YAG laser, and the laser beam L1 has a wavelength of 1060 nm and an output intensity of 5 watts. Element 2
Is an optical element that makes the intensity distribution of the luminous flux of the laser light emitted from the laser 1 uniform. The optical system 3 includes a reflecting mirror 4, a reflecting mirror 5, a reflecting mirror 6, a reflecting mirror 7 and a lens 8. The rotation axis 9a of the optical system rotation support 9 that supports the optical system 3 coincides with the axis 8a of the lens 8. Workpiece 1
0 is a stainless plate having a thickness of 0.02 to 1.0 mm.

The element 2 will be described with reference to FIG. FIG. 2 is a conceptual diagram of the element. The element 2 is a silica-based step-type optical fiber having a length of 1 m in which a synthetic silica core 2a having a diameter of 200 μm is covered with a fluorine-doped synthetic silica clad 2b having a thickness of 20 μm. The outside of the clad 2b has a thickness of 50 μm.
Is covered with an organic coating layer 2c that does not transmit the light. Both ends of the element 2 are respectively a plane incidence end 2d and a plane emission end 2e. The refractive index n0 of the core 2a is uniform over the entire cross section. The refractive index n0 and the refractive index n1 of the cladding 2b are n0 = 1.46 and n1 = 1.44, respectively.

FIG. 3 is a diagram showing the refractive index distribution in the cross section of the element 2, with the vertical axis representing the refractive index and the horizontal axis representing the distance in the cross sectional direction. As shown in FIG. 3, the refractive index distribution of the cross section of the element 2 is such that the high refractive index portion of the core 2a rises vertically between the low refractive index portions of the clad 2b on both sides and the high refractive index portion has a horizontal line. I am drawing. It is a so-called top hat type.

Next, the distribution of light intensity will be described. 4 and 5 are views showing the distribution of the light intensity in the cross section of the light flux of the laser light. As shown in FIG. 4, the light intensity of the cross section of the light flux of the laser light L1 emitted from the laser 1 has the highest light intensity in the central portion and the lowest light intensity in the peripheral portion. Depending on the type of laser, in addition to the highest light intensity in the central portion as shown in FIG. 4, there are also lasers having a plurality of maximum values in the central portion as shown in FIG. In any case, there is no constant light intensity.

FIG. 6 is a diagram showing the distribution of the light intensity in the cross section of the light flux of the laser light emitted from the device. The light intensity of the cross section of the light flux of the laser light emitted from the element 2 is shown in FIG.
As shown in (3), it is constant over the entire cross section, that is, from the boundary between the core 2a and the clad 2b to the other boundary through the central portion.

The above-mentioned measurement of the light intensity distribution was performed by the so-called pinhole scan method. That is, the pinhole was moved in a cross-sectional direction perpendicular to the laser light, and the intensity of light passing through the pinhole was measured by a photodetector.

For comparison, measurements were made on other devices. The other element is a glassy silicon oxide (GeO2 --SiO2) having a diameter of 10 .mu.m, which has a large content of germanium oxide in the central portion and is gradually decreased toward the peripheral portion.
2) is a silica-based optical fiber having a fiber-like shape with a length of 1 m in which a core of 1) is coated with a clad of pure glassy silicon oxide (SiO2) having a thickness of 1 μm. The core has a refractive index of 1.4650 and the cladding has a refractive index of 1.4580.

FIG. 7 is a diagram showing the refractive index distribution in the cross section of the device. As shown in Fig. 7, the refractive index distribution in the cross section of the other element has the low refractive index portions of the clad on both sides, and the refractive index increases toward the central part from that, and the maximum refractive index is present in the central part of the core. There is a value part. The distribution is close to the so-called normal distribution curve.

FIG. 8 is a diagram showing the distribution of the light intensity in the cross section of the luminous flux of the laser light emitted from the element. As shown in FIG. 8, the light intensity of the cross section of the laser beam emitted from the other element gradually increases from the boundary between the core and the clad toward the central portion, and reaches the maximum at the central portion. It gradually decreases toward the periphery. Draw a curve close to the so-called normal distribution curve.

Next, the operation will be described. The laser light L1 emitted from the laser 1 is incident from the incident end 2d of the element 2 through an incident lens (not shown), the intensity distribution of the light flux is made uniform, and the laser light L1 is emitted from the emission end 2e. Then, the light enters the optical system 3, and the reflecting mirror 4, the reflecting mirror 5, the reflecting mirror 6, and the reflecting mirror 7 are sequentially arranged.
And is focused by the lens 8 to have a diameter of 0.1 μm. The focus point 11 is located off the axis 8a of the lens 8. Optical system rotation support 9
When is rotated, the optical system 3 rotates about the rotation axis 9a, that is, the axis 8a. The point 11 is burnt out by the irradiation of the laser beam L1 and moves as the optical system 3 rotates. When the optical system 3 makes one rotation, the locus of the point 11 draws a circle around the axis 8a, and a circular hole 12 is drilled in the workpiece 10. The diameter of the obtained circular hole 12 is in the range of 10 to 100 μm. The roundness of the perforated circular hole 12 is about 1 μm, and the peripheral portion is sufficiently smooth.

For comparison, when the above-mentioned work was carried out by using the above-mentioned other element instead of the element 2, the smoothness of the peripheral portion of the perforated circular hole was inferior, which is not the same as this example. It was

In another embodiment, the element 2 is replaced by a multi-component step type optical fiber whose core and clad are sodium oxide-boron oxide-silicon oxide (Na2 O-B2 O3-SiO2). I was able to get the result.

[0022]

According to the present invention, there is provided a light intensity homogenizing element for easily homogenizing the intensity distribution of laser light, and by using the light intensity homogenizing element, a metal plate is machined with high accuracy and the periphery of the machined portion is smooth. A laser processing machine is provided.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a laser processing machine according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram of a cross section of a light intensity distribution uniformizing device according to an embodiment of the present invention.

FIG. 3 is a conceptual diagram of a refractive index distribution in a cross section of a light intensity distribution uniformizing device according to an embodiment of the present invention.

FIG. 4 is a conceptual diagram of a light intensity distribution of a cross section of a light flux of a laser according to an embodiment of the present invention.

FIG. 5 is a conceptual diagram of a light intensity distribution on a cross section of a laser.

FIG. 6 is a conceptual diagram of a light intensity distribution of a cross section of a light beam emitted from a light intensity distribution uniformizing device according to an embodiment of the present invention.

FIG. 7 is a conceptual diagram of a light intensity distribution of a cross section of a laser light beam.

FIG. 8 is a conceptual diagram of a light intensity distribution of a cross section of a laser light beam.

[Explanation of reference numerals] 1 ... laser, 2 ... element, 3 ... optical system, 4,
5, 6, 7 ... Reflecting mirror, 8 ... Lens, 10 ...
Workpiece, 11 ... Circular hole, L1 ... Laser light

Claims (3)

[Claims] 1. A laser light source, a light intensity homogenizing means, and an optical means are provided, and the light intensity homogenizing means homogenizes the light intensity of the cross section of the light flux of the laser light emitted from the laser light source, The laser processing machine is characterized in that the optical means focuses the laser light on a workpiece to process the workpiece. 2. The light intensity homogenizing means is an optical fiber comprising a core and a clad covering the outer periphery of the core, and the refractive index of the core is constant at least in the cross-sectional direction, The laser beam machine according to claim 1, wherein the intensity distribution of the light incident from one end is made uniform and the light is emitted from the other end. 3. An optical fiber comprising a core and a clad covering the outer circumference of the core, wherein the refractive index of the core is at least constant in the cross-sectional direction, and the intensity distribution of light incident from one end Is uniformized and emitted from the other end.