JP6695610B2 - Laser processing apparatus and laser processing method - Google Patents

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 shots must be repeated several tens to several hundreds of times in order to make one hole in a work (workpiece).

  Conventionally, in the perforation processing by the laser, a galvanometer mirror was used as shown in FIG. 9, and adjustment was made so that the focus was on a predetermined portion of the work. That is, in the conventional laser processing apparatus, the laser beam L from the light source S has a predetermined optical path by the two Galvano mirrors 10 and 11 (the respective mirrors are rotationally driven and controlled about the axes 10a and 11a). The focusing lens 12 (also referred to as “fθ lens”) is controlled so as to focus on the surface of the work W or its vicinity, and the positions of the galvano mirrors 10 and 11 are determined. After that, the required number of laser shots are taken. However, the galvanometer mirror has a drawback that it operates slowly.

  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 simultaneously provided (Patent Document 1). However, there has been a demand for a laser processing apparatus and a laser processing method that can further speed up processing.

JP, 2002-113711, A

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

In order to solve the above problems, a laser processing apparatus of 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 as described in claim 1. A polygon mirror that is driven to rotate, a condenser lens that focuses the laser beam reflected by the polygon mirror on or near the surface of the workpiece, and a laser beam that is provided in the optical path of the laser beam. at least includes a diffraction grating for splitting on a straight line, in a predetermined one direction, the polygon mirror by being rotated, a plurality of light beams branched is deflected to the one direction, with respect to the workpiece The feature is that the holes are drilled so that they are arranged in a staggered pattern.

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

  Further, the laser processing apparatus of the present invention can include a cylindrical lens on the laser beam emitting side of the condenser lens.

Laser processing method of the present invention uses a laser machining apparatus of any one of the above, after the laser beam the light source is emitted to the diffraction grating is branched and hole formation in a straight line in a predetermined one direction,
The moves in the direction perpendicular to the workpiece in the predetermined direction, said by rotating the polygon mirror, deflects the laser beam branching to the one direction, as holes are arranged in a staggered manner Characterized by processing.

  A laser processing apparatus of the present invention includes a light source that emits a laser beam, a polygon mirror that includes a plurality of mirror surfaces that reflects and deflects and scans a laser beam emitted from the light source, and is driven to rotate. With a configuration including at least a condensing lens that focuses a laser beam reflected by the polygon mirror in the vicinity, and a diffraction grating that branches the laser beam into a plurality of beams in the optical path of the laser beam, Since the correction of the aberration between the lenses is completed only by the condensing lens, a simple device configuration becomes possible, and the processing speed becomes constant and high-speed processing becomes possible.

  Further, the laser processing apparatus of the present invention can be provided with a cylindrical lens on the laser beam emitting side of the condenser lens, and at that time, it is possible to improve the processing accuracy.

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

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 in model. It is a figure which shows as a model an example of the deflection operation of the laser beam by a polygon mirror. It is a model figure which shows the example of many holes formed in the workpiece | work by processing. The arrow in the figure indicates the movement direction of the work. 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 a 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 and has a plurality of mirror surfaces, as a deflector that reflects and deflects and scans the laser beam L emitted from the light source S. The bend mirror 3 that guides the light beam reflected by the polygon mirror 2 to the condenser lens 4, the condenser lens 4 that focuses the laser beam on or near the surface of the workpiece W, the 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 and.

  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 disc shape made of transparent plastic (in this example, an antireflection film is applied, and 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 into a plurality of branches due to the minute unevenness formed on the one surface. The plurality of branched laser beams are aligned on a straight line when projected on the screen C as shown in the model of FIG. That is, the diffraction grating 1 is a diffraction grating that splits the incident laser beam L into a plurality of (100 in this example) light 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, for easy understanding, one laser beam is incident on the polygon mirror 2). It is a model figure explaining a case.). The polygon mirror 2 is rotationally driven, but has a plurality of mirror surfaces rotationally symmetric with respect to the axis thereof, and is a deflecting body for deflecting the laser beam L. As indicated by the arrow in FIG. 3, the laser beam reflected can be largely moved from the position shown by the solid line to the position shown by the broken line by only slightly rotating the polygon mirror 2. Then, when the polygon mirror 2 is further slightly rotated in the same direction, the laser beam can be returned to the original position shown by the solid line by the next mirror surface. As described above, by using the polygon mirror 2, the distribution position of the light beam can be returned to the original position without the need to change the rotation (rotation) direction as in the case of using the galvanometer mirror. Is possible.

  In the example shown in FIG. 1, the plurality of laser beams reflected by the mirror surface of the polygon mirror 2 are guided to the condenser lens 4 by the bend mirror 3, and are condensed on the surface of the work W or in the vicinity thereof by the condenser lens 4. 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. With this configuration, the correction of the inter-lens aberration is completed only by the condensing lens, and therefore the configuration is simple. Is possible, the processing speed is constant, and high-speed processing is possible.

  On the other hand, the configuration using the galvanometer mirror has the following disadvantages. That is, as shown in FIG. 9, a device using two galvanomirrors cannot sufficiently correct the aberration, resulting in processing variation, and a device using three galvanomirrors sufficiently corrects the aberration. However, the galvano mirror has many folding operations, and the processing speed is reduced.

  FIG. 4 schematically shows a state of punching to obtain a secondary battery separator from a synthetic resin sheet by 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 those which are simultaneously drilled by the laser beams branched into a plurality (100 in this example) by the diffraction grating 1, and the arrows in the drawing after the processing are completed. The workpiece is moved in the same direction, and the boring process for the next row is restarted. At that time, the polygon mirror 2 is rotationally driven, and the plurality of laser beams are deflected in the vertical direction so that the holes are arranged in a zigzag pattern.

  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 of the diffraction grating or the condenser lens, the mounting position accuracy, or the surface accuracy of the mirror There is. In that case, for example, by disposing a plano-convex cylindrical lens having a semi-cylindrical shape or a partially cylindrical shape in the laser optical path, it is possible to correct the focus position and improve the accuracy.

  FIG. 5 shows an example of a laser processing apparatus in which the cylindrical lens 5 is arranged on the laser beam emitting 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, and the plane on the outgoing side is parallel to the processing surface of the sheet-shaped workpiece W, and of the convex curved surface of the cylindrical lens 5. The cylindrical lens 5 is provided so that the line segment of the parietal portion exists on a plane including a plurality of branched laser beams.

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

  Normally, all of the plurality of laser beams L emitted from the condenser lens enter 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 or near the surface of the work. However, as described above, the laser beam that is off the same plane for some reason enters the cylindrical lens 5 from a position farther than the crown of the convex curved surface, and is corrected by refraction by the cylindrical lens 5 depending on the position, Aligned in line at the focal position. Thus, it is possible to improve the processing accuracy by using the cylindrical lens 5 together.

  In the example shown in FIG. 1, the diffraction grating 1 is arranged between the light source S and the polygon mirror 2, but the present invention is not limited to this example. That is, the laser of the present invention in which the diffraction grating 1 is arranged between the bend mirror 3 and the condenser lens 4 in FIG. 7 and between the emission side of the condenser lens 4 and the work W in FIG. An example of the processing device is shown.

  The present invention has been described above with reference to the preferred embodiments, but the laser processing apparatus and the laser processing method of the present invention are not limited to the configurations of the above embodiments.

  Those skilled in the art can appropriately modify the laser processing apparatus and the laser processing method of the present invention according to the conventionally known knowledge. Such modifications are of course included in the scope of the present invention as long as they have the configurations of the laser processing apparatus and the laser processing method of the present invention.

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 rotationally driven and that includes a plurality of mirror surfaces that deflect and scan the 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;
Comprising at least a diffraction grating for splitting on a straight line the laser beam provided in an optical path in a predetermined one direction of the laser beam,
By the polygon mirror is rotated, a laser, wherein a plurality of light beams branched is deflected to the one direction, to hole formation as staggered with respect to the workpiece Processing equipment.   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 light beams in the same plane.   The laser processing apparatus according to claim 1 or 2, wherein a cylindrical lens is provided on the laser beam emitting side of the condenser lens. A laser processing method using the laser processing device according to claim 1.
After the laser beam the light source is emitted to the diffraction grating is branched and hole formation in a straight line in a predetermined one direction,
Moving the workpiece in a direction orthogonal to the predetermined direction,
Wherein by rotating the polygon mirror, deflects the laser beam branching to the one direction, the laser processing method characterized by processing such holes are arranged in a staggered manner.

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