JP2017013081A - Laser processing device and laser processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser processing device capable of increasing a processing speed.SOLUTION: A laser processing device comprises at least: a light source projecting a laser beam; a polygon mirror, which has a plurality of mirror surfaces reflecting the laser beam projected from the light source to perform deflection-scanning, and which is rotationally driven; a condenser lens focusing the laser beam reflected by the polygon mirror on a surface of work-piece or on a vicinity of the work-piece; and a diffraction grating branching the laser beam into a plurality of beams in a light path of the laser beam.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a processing method such as drilling using a laser and a laser processing apparatus that can be used for such processing.

  A laser having a high repetition rate has low energy per shot, and the shot must be repeated several tens to several hundreds of times in order to open one hole in the workpiece (workpiece).

  Conventionally, a porous processing by a laser has been adjusted using a galvano mirror as shown in FIG. That is, in the conventional laser processing apparatus, the laser beam L from the light source S becomes a predetermined optical path by the two galvanometer mirrors 10 and 11 (respective mirror portions are rotationally driven and controlled about the axes 10a and 11a). Thus, the condenser lens (sometimes referred to as “fθ lens”) 12 is controlled to focus on the surface of the workpiece W or in the vicinity thereof, and the positions of the galvanometer mirrors 10 and 11 are determined. Later, the necessary number of laser shots are taken. However, galvanometer mirrors have the disadvantage of slow operation.

  Here, a technique has been proposed in which a diffraction grating is arranged in the optical path of a laser beam and a plurality of through holes are provided simultaneously (Patent Document 1). However, there has been a demand for a laser processing apparatus and a laser processing method that can further increase the processing speed.

JP 2002-113711 A

  An object of the present invention is to provide a laser processing apparatus and a laser processing method capable of improving the above-described conventional problems, that is, improving the processing speed.

  In order to solve the above problems, a laser processing apparatus according to the present invention includes a light source that emits a laser beam and a plurality of mirror surfaces that reflect and scan the laser beam emitted from the light source. A polygon mirror that is driven to rotate, a condensing lens that focuses the laser beam reflected by the polygon mirror on the surface of the workpiece or in the vicinity of the surface, and a plurality of light beams in the optical path of the laser beam And at least a diffraction grating for branching.

  In the laser processing apparatus of the present invention, the diffraction grating can be a diffraction grating that branches the laser beam into a plurality of beams in the same plane.

  Moreover, the laser processing apparatus of this invention can provide a cylindrical lens in the said laser beam emission side of the said condensing lens.

  The laser processing method of the present invention is characterized by using any one of the laser processing apparatuses described above.

  A laser processing apparatus according to the present invention includes a light source that emits a laser beam, a polygon mirror that includes a plurality of mirror surfaces that reflect and deflect and scan the laser beam emitted from the light source, and a workpiece surface or the surface. By a configuration comprising at least a condenser lens for focusing the laser beam reflected by the polygon mirror in the vicinity, and a diffraction grating for branching the laser beam into a plurality of beams in the optical path of the laser beam, Since the correction of aberrations between the lenses is completed with only the condensing lens, a simple device configuration is possible, the processing speed is constant, and processing can be performed at high speed.

  Moreover, the laser processing apparatus of this invention can provide a cylindrical lens in the said laser beam emission side of the said condensing lens, and it becomes possible to aim at the improvement of a processing precision then.

  The laser processing method of the present invention can improve the processing speed by using any of the laser processing apparatuses described above.

It is a model figure which shows an example of the laser processing apparatus of this invention. It is a figure which shows an example of the branch of the laser beam by a diffraction grating as a model. It is a figure which shows an example of deflection | deviation operation of the laser beam by a polygon mirror as a model. It is a model figure which shows the example of many holes formed in the workpiece | work by process. The arrow in the figure is the moving direction of the workpiece. It is a model figure which shows the other example (example which uses a cylindrical lens together) of the laser processing apparatus of this invention. FIG. 6A is a model perspective view of an example of a cylindrical lens. FIG. 6B is a model diagram for explaining the effect of improving the accuracy of the focal position by the cylindrical lens. It is a model figure which shows the other example (example in which the diffraction grating is arrange | positioned at the incident side of the condensing lens) of the laser processing apparatus of this invention. It is a model figure which shows the other example (example in which the diffraction grating is arrange | positioned at the output side of the condensing lens) of the laser processing apparatus of this invention. It is a model figure which shows the structure of the conventional laser processing apparatus.

  An example of the laser processing apparatus of the present invention will be described with reference to the drawings.

FIG. 1 is a model configuration diagram showing an example of a laser processing apparatus of the present invention.
This laser processing apparatus includes a light source S that emits a laser beam, a polygon mirror 2 that is rotationally driven as a deflecting body that reflects and scans the laser beam L emitted from the light source S, and includes a plurality of mirror surfaces; A bend mirror 3 that further guides the light beam reflected by the polygon mirror 2 to the condensing lens 4, a condensing lens 4 that focuses the laser beam on or near the surface of the workpiece W, a light source S, and the polygon mirror 2 And a diffraction grating 1 for branching the laser beam L into a plurality of beams in the optical path of the laser beam L between the two.

  Here, Example 1 of the diffraction grating used in the example of the laser processing apparatus will be described with reference to FIG. 2 which is a model diagram.

  The diffraction grating 1 has a disk shape made of transparent plastic (in this example, an antireflection film is provided. It may be made of glass or quartz instead of plastic). When the laser beam L is incident from one surface, the laser beam is diffracted and branched into a plurality by the minimal unevenness formed on the one surface. The plurality of branched laser beams are aligned in a straight line when projected on the screen C as shown in model form in FIG. In other words, the diffraction grating 1 is a diffraction grating that splits the incident laser beam L into a plurality of (in this example, 100) beams in the same plane.

  Further, the polygon mirror 2 used in the example of the laser processing apparatus of FIG. 1 will be described with reference to FIG. 3 (in this figure, one laser beam incident on the polygon mirror 2 is shown for easy understanding). It is a model figure explaining a case.). Although the polygon mirror 2 is driven to rotate, the polygon mirror 2 is a deflecting body that deflects the laser beam L and has a plurality of rotationally symmetric mirror surfaces. As indicated by the arrows in FIG. 3, the laser beam reflected from the position indicated by the solid line to the position indicated by the broken line can be greatly moved by only slightly rotating the polygon mirror 2. When the polygon mirror 2 is further rotated slightly in the same direction, the laser beam can be returned to the original position indicated by the solid line by the next mirror surface. Thus, by using the polygon mirror 2, the light distribution position can be returned to the original without changing the rotation (turning) direction as in the case of using the galvanometer mirror, so that a quick deflection operation is possible. Is possible.

  In the example shown in FIG. 1, a plurality of laser beams reflected by the mirror surface of the polygon mirror 2 are guided to the condensing lens 4 by the bend mirror 3, and the condensing lens 4 brings the surface of the workpiece W to the vicinity thereof or the vicinity thereof. Focus on each.

  The laser processing apparatus of the present invention has a configuration including a polygon mirror and a diffraction grating as in the above example, and with this configuration, correction of inter-lens aberration is completed with only a condensing lens. Therefore, the processing speed is constant and high-speed processing is possible.

  In contrast, the configuration using the galvanometer mirror causes the following inconvenience. That is, in the apparatus using two galvanometer mirrors as shown in FIG. 9, the aberration cannot be sufficiently corrected and processing variation occurs, and in the apparatus using three galvanometer mirrors, the aberration is sufficiently corrected. Although it is possible to do so, the galvano mirror is often turned back, and the processing speed is reduced.

  FIG. 4 shows a model of a state of punching in order to obtain a secondary battery separator from a synthetic resin sheet using the example of the laser processing apparatus shown in FIG.

  In FIG. 4, the holes h arranged in a line in the vertical direction are simultaneously drilled by laser beams branched into a plurality (100 in this example) by the diffraction grating 1. The workpiece is moved in the direction and the drilling of the next row resumes. At that time, the polygon mirror 2 is rotationally driven, and the plurality of laser beams are deflected in the vertical direction and processed so that the holes are arranged in a staggered manner.

  In the laser processing apparatus shown in FIG. 1, when a part of a plurality of branched light beams deviates from the same plane due to the manufacturing accuracy and mounting position accuracy of the diffraction grating and the condenser lens, or the surface accuracy of the mirror. There is. In that case, for example, by arranging a plano-convex cylindrical lens such as a semi-cylindrical shape or a partial cylindrical shape in the laser light path, the focal position can be corrected and the accuracy can be improved.

  FIG. 5 shows an example of a laser processing apparatus in which the cylindrical lens 5 is arranged on the laser beam emission side of the condenser lens 4. In this example, the convex curved surface of the cylindrical lens 5 is on the laser beam incident side, the emission side plane is parallel to the processing surface of the sheet-like workpiece W, and the convex curved surface of the cylindrical lens 5 is formed. The cylindrical lens 5 is provided so that it exists in the plane containing the several laser beam from which the line segment of the top part was branched.

  FIG. 6A shows a perspective view of the cylindrical lens 5, and FIG. 6B shows a model diagram for explaining its function.

  The plurality of laser beams L emitted from the condenser lens are all incident on the cylindrical lens 5 from the top of the convex side surface of the cylindrical lens 5, and go straight without being affected by the cylindrical lens 5. Then, focus on the surface of the workpiece or its vicinity. However, as described above, the laser beam deviating from the same plane for some reason enters the cylindrical lens 5 from a position away from the top of the convex curved surface, and is corrected by refraction by the cylindrical lens 5 according to the position. Align in line at the focal position. As described above, the combined use of the cylindrical lens 5 can improve the processing accuracy.

  In the example shown in FIG. 1, the diffraction grating 1 is disposed between the light source S and the polygon mirror 2, but the present invention is not limited to this example. That is, FIG. 7 shows the laser of the present invention in which the diffraction grating 1 is arranged between the bend mirror 3 and the condenser lens 4 and FIG. 8 shows that the diffraction grating 1 is arranged between the exit side of the condenser lens 4 and the workpiece W. An example of a processing apparatus is shown.

  In the above, an example using a diffraction grating that splits a laser beam into a plurality of light beams in the same plane has been described. It is also possible to use a diffraction grating that branches into a plurality of light beams.

  In processing using a laser beam, shots are repeated several tens to several hundreds of times on the workpiece to be processed. For example, the laser beams are arranged in parallel in a plurality of columns that are equally spaced from each other and in a plurality of rows that are equally spaced from each other. Using a laser processing apparatus equipped with a diffraction grating for branching in an array, the polygon mirror is driven to rotate once to a plurality of shots, for example, one row or several rows (or one column). It is also possible to simultaneously process a plurality of locations by moving the locations to be processed and processing them at a time.

  Although the present invention has been described with reference to the preferred embodiment, the laser processing apparatus and the laser processing method of the present invention are not limited to the configuration of the above embodiment.

  A person skilled in the art can appropriately modify the laser processing apparatus and the laser processing method of the present invention in accordance with conventionally known knowledge. Such modifications are still included in the scope of the present invention as long as the laser processing apparatus and the laser processing method of the present invention are provided.

S light source L laser beam 1 diffraction grating 2 polygon mirror 3 bend mirror 4 condenser lens W work

Claims (4)

A light source that emits a laser beam;
A polygon mirror that is rotated and provided with a plurality of mirror surfaces that reflect and deflect and scan a laser beam emitted from the light source;
A condenser lens for focusing the laser beam reflected by the polygon mirror on the surface of the workpiece or in the vicinity of the surface;
A laser processing apparatus comprising at least a diffraction grating for splitting the laser beam into a plurality of beams in an optical path of the laser beam.   The laser processing apparatus according to claim 1, wherein the diffraction grating is a diffraction grating that branches the laser beam into a plurality of beams in the same plane.   The laser processing apparatus according to claim 1, wherein a cylindrical lens is provided on the laser beam emission side of the condenser lens.   The laser processing method using the laser processing apparatus of any one of Claim 1 thru | or 3.

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