DE102007037133A1 - Method for producing material-attenuation regions/perforations in a substrate, comprises introducing a laser-light beam on a substrate, projecting a projection lens of the light beam and diffracting light into the partial light beam - Google Patents

Abstract

The method for producing material-attenuation regions/perforations in a substrate (13), comprises introducing a laser-light beam on the substrate, projecting a projection lens (1) of the light beam, and diffracting light into the partial light beam, which forms discrete light spots on the substrate. The projection lens comprises a diffractive optical element (5), which divides the light beam into the partial beams of light by diffraction. The substrate is moved at the projection lens. The material-attenuation regions are formed in a pre-determined arrangement. The method for producing material-attenuation regions/perforations in a substrate (13), comprises introducing a laser-light beam on the substrate, projecting a projection lens (1) of the light beam, and diffracting light into the partial light beam, which forms discrete light spots on the substrate. The projection lens comprises a diffractive optical element (5), which divides the light beam into the partial beams of light by diffraction. The substrate is moved at the projection lens. The material-attenuation regions are formed in a pre-determined arrangement. The diffractive optical element is arranged in different directions and has diffractive optical zones in correspondence to the pre-determined arrangement of material attenuation-regions or perforations. The diffractive optical zones cause different intensity, beam width, form and/or divergence of the partial light beam. The attenuation region and/or the perforation is preset directly by the diffraction of light characteristics of the assigned light spot producing diffractive zone. The light beam is radiated from an optical fiber. The projection lens comprises an inlet lens and an outlet lens. A beam diameter of the light beam or the partial light beam is adjusted to each other by varying the distance of the inlet lens to the optical fiber and/or the distance of the lenses. The diffractive optical element is arranged between the inlet lens and the outlet lens. The material-attenuation regions are through holes, holes and/or attenuation region, whose forms are preset by the arrangement of the diffractive projection lens. The material-attenuation regions or perforations are formed through thermal melting or ablation of material of the substrate. An independent claim is included for a device for producing material-attenuation regions/perforations in substrate.

Description

Field of the invention

The The present invention relates generally to the processing of substrates or materials, in particular of sheet-like or sheet-like materials made of any materials, preferably of plastic, sheet metal, Paper, cardboard or tissue, and in particular relates to the training of material weakening areas or perforations in such substrates or materials with the help of laser beams.

Background of the invention

A conventional method for forming perforations in a substrate is in US 4,568,815 disclosed. In this case, a plurality of perforations are formed at equal distances from one another in a web-shaped substrate moved evenly past a laser by laser ablation or thermal melting. In order to specify the positions of the perforations, the laser beam is pulsed by means of a high frequency shutter and / or the laser beam is deflected by means of a rotatable scanner mirror. The mechanical inertia of the scanner mirror limits the processing speed and increases the maintenance.

Similar devices employing a beam deflector scanner mirror in forming weakened areas or perforations in materials are disclosed in US Pat DE 200 13 469 U1 and DE 199 45 022 A1 disclosed.

Especially if areas of weakness or Perforations at widely spaced positions on one Substrate must be formed limits the inertia scanner mirrors the processing speed. An approach to increase the processing speed, consists in the simultaneous use of multiple laser beams by means of associated scanner levels and imaging optics are mapped appropriately. However, this increases the effort in material processing considerably.

Summary of the invention

task It is the object of the present invention to provide a method and an apparatus for producing a plurality of material weakening areas or perforations to provide with the help of light rays, bringing in easier Make a high processing speed at the same time lower thermal stress of the substrate can be realized. A preferred application of the invention is thereby the formation of Predetermined breaking points or lines in paper, cardboard, sheet metal or Plastic materials concern.

The The above and other objects are achieved by a method Claim 1 and solved by a device according to claim 12. Further advantageous embodiments are the subject of the referenced Dependent claims.

at a method according to the present invention Invention shares an imaging optics the light beam, preferably Laser light beam, by diffraction into a plurality of light simultaneously of partial light rays, which are applied to the substrate or Material to be mapped, where these are a plurality of discrete Train light spots. These cause by the energy input According to the invention the training a plurality of discrete material weakening areas or perforations in the material, by thermal Melting or laser ablation of substrate material at the positions of the several discrete spots of light. The present invention is suitable basically for processing any materials. Preference is given to thin materials with a flat surface in the area to be edited. Preferably, the material should be at the wavelength the light source or the laser beam have the lowest possible reflectivity, to optimize the energy input into the material.

Consequently can according to the invention several at Material-weakening areas or perforations formed in the material to be processed become. A time-consuming and expensive beam deflection is not according to the invention required. As is known, light rays divided in a simple manner into a plurality of partial light beams become. As to the formation of a material weakening area or perforations each discreet light spot requires a certain minimum power is, the inventive method is practically only the restriction, that the respective partial light beams still have sufficient intensity or power have to have to the material in the desired At the same time at the plurality of discrete locations. This let yourself by suitable design of the beam splitter and by suitable Choice of the light output of the input light beam in almost any Realize way.

According to the invention, the partial light beams are imaged and deflected by the imaging optics directly in order to simultaneously form a plurality of material weakening areas or perforations. The use of a diffractive optical element (DOE) assigned to the imaging optics has proven to be particularly expedient for suitable beam splitting, since in this way Even high light intensities can be almost lossless and shared with a suitable beam profile of the partial light beams. In particular, diffractive optical elements can also be used to easily realize further beam shaping, in particular with regard to the beam cross section, the intensity, shape or beam profile and / or divergence of the respective partial light beams.

According to one another embodiment are the material weakening areas or perforations in a predetermined geometric arrangement specified. This can, for example, by the respective intended use be conditioned by the substrate or material to be processed. Should For example, a circumferential line of material weakening areas under a substrate surface be set, for example, to form a circumferential Fracture line in a plastic material of an airbag cap, so it will preferred according to the invention, if all Material-weakening areas the circumferential line simultaneously in the substrate or material be formed. According to the invention, the diffractive optical Element designed and designed so that the partial light rays in correspondence with this predetermined arrangement of material weakening areas or perforations and directed in corresponding directions and be pictured. It is advantageous that a more elaborate Distraction of the partial light rays is not required. To change of the method to a different geometric arrangement of the material weakening areas or perforations, the diffractive optical element can thereby be interchangeable, for example in a revolver unit or another rotating or changing device are kept.

By The imaging properties of imaging optics can also for the Material processing important parameters, such as light intensity and beam profile, be given suitable. According to one another embodiment the imaging properties of the imaging optics are chosen such that the material weakening areas below the imaging optics surface facing the Substrate are formed, ie in the depth of the processed Material or on the back of the imaging optics of the substrate or material to be processed.

According to one another embodiment becomes the geometric shape of the weakened areas or perforations directly by the light diffraction properties of the diffractive Imaging optics, in particular an associated diffractive region a diffractive optical element, given, with which the associated Light spot is generated, which the respective weakening range or the respective perforation forms. Corresponds for example the contour of a weakened area or a perforation of the shape of a slot, so in the diffractive imaging optics, in particular in an associated diffractive zone thereof, a partial light beam divided in such a way and imaged by laser ablation or thermal fusion of the substrate material directly the weakened area or the perforation with the desired Contour without forming a further mechanical beam deflection and / or a relative displacement of substrate and laser beam required would.

Basically be provided that the imaging optics several diffractive optical Elements are assigned, for example, held directly in this are suitable for the input beam in a variety of Partial light rays to divide. However, preference is given according to a another embodiment used a single diffractive optical element, the total is penetrated by the input partial light beam and a plurality of diffractive optical zones or active zones, whose Arrangement and design are matched to the aforementioned predetermined arrangement of material weakening areas or Perforations. Thus, the diffractive optical element has a or more diffractive optical zones or active zones, for example, in the form of alternating raised and recessed line, circular or elliptical Zones or alternating areas with different refractive index or otherwise, as appropriate light diffractive structures formed are. These active zones are preferably on a single, for the input light beam provided transparent substrate, which is also interchangeable in the Beam path of the input light beam can be held.

According to one preferred aspect of the present invention is each of designed diffractive optical zones of the diffractive optical element, around the associated partial light beam a suitable intensity, a suitable beam cross-section, a suitable beam shape and / or Impose beam divergence. Thus, you can the individual diffractive optical zones differ in any way be designed.

Especially Thus, partial light beams with different intensities can also be made easier Realize such that material weakening areas or perforations, such as rupture lines, simultaneously with different Energy input can be generated from a single input light beam can.

In accordance with another aspect of the present invention, the imaging optics include at least one input lens and an outlet lens spaced therefrom in the beam direction, so that a larger or smaller diameter of the laser beam can be adjusted by varying the distance. When using an optical waveguide, in particular a glass fiber, for coupling the input light beam into the imaging optical system, the distance between the input lens and the output side of the optical waveguide can furthermore be varied, which opens up further degrees of freedom.

According to one Another aspect of the present invention is the diffractive optical element between the aforementioned input lens and output lens arranged, which facilitates adjustment and adjustment tolerances decreases. At the same time, the diffractive optical element together with the input and output lens in a modular optical unit sealed housed be. The housing The imaging optics can be designed to be a change of the diffractive optical element for forming another Arrangement of processing points to allow, for example by means a revolver unit or another rotary or exchange unit, wherein several differently formed diffractive optical Elements are kept.

A preferred application of the method relates to the formation of predetermined breaking lines or predetermined breaking points in any materials, for example in Paper, cardboard, sheet metal or plastic materials. In these Applications can according to the invention simultaneously several material weakening areas or perforations, by appropriate division a light beam, preferably a laser beam, in a plurality of partial light rays under simultaneous appropriate deflection and imaging of the same the material to be processed in a predetermined geometric Arrangement. A complex sequential deflection of a laser beam by means of a scanner optics is not required according to the invention. Consequently high processing speeds can be achieved. simultaneously is the thermal load of the material to be processed negligible. The diffractive optical element to be used can be designed in this way that at the same time a plurality of predetermined breaking points are formed can. The inventive method is also suitable for Material processing with high throughput. The partial light rays can thereby generated in particular with different intensities or powers so that at the same time material weakening areas or perforations can be set with different interpretation, for example, with different geometric two- or three-dimensional shapes, sizes and / or Deep.

LIST OF FIGURES

following the invention will be described by way of example and with reference on the attached Drawings are described, resulting in more features, benefits and to be solved Tasks will result. Show it:

1 a schematic representation of a system for the simultaneous formation of a plurality of material weakening areas or perforations in a sheet material according to the present invention;

2 in an enlarged sectional view of an imaging optics of the system according to the 1 ; and

3 in a schematic plan view and in a section of a substrate in which a predetermined breaking lines has been formed by the method according to the invention.

In the figures denote identical reference numerals identical or Substantially equal elements or groups of elements.

Detailed description of exemplary embodiments the invention

According to the 1 becomes the laser beam of a diode laser 8th in a fiberglass 9 coupled and forwarded to the plant, where a processing head an imaging optics 1 with an associated diffractive optical element (DOE) 5 wearing. Through the imaging optics 1 becomes the input light beam 10 in a plurality of partial light rays 12a - 12c divided. At the same time they are properly focused. The distance between the machining head and the substrate 13 is therefore in accordance with the achieved focal length of the imaging optics 1 and the desired diameter of the beam spots on the substrate 13 selected. By way of example, a distance between the machining head and the substrate to be processed of the order of magnitude of about 10 cm to about 50 cm was realized. According to the 1 be on the surface of the substrate 13 a plurality of light spots formed, for example, in a regular arrangement, of which only three light spots for forming material weakening areas or perforations are shown, as described in more detail below. The light spots on the substrate 13 are formed in a suitable geometric arrangement, which is predetermined for example by a proper application. In the plane of the substrate 13 the geometric arrangement of the light spots can be almost arbitrary. For suitable imaging and deflection of the partial light rays 12a - 12c only needs the imaging optics 1 and the diffractive optical element 5 be designed suitably, as described in more detail below.

For adjusting the imaging optics 1 is an adjusting device 4 provided, in particular, as in the 2 shown, the distance z1 of the input lens 2 the imaging optics 1 to the exit side of the fiber 9 and / or the distance z2 between the input lens 2 and the associated output lens 3 the imaging optics 1 may vary suitably to the diameter of the input light beam 10 and the partial light rays 12a - 12c as well as the light spots suitable, which can have an influence on the light intensity per light spot.

According to the 1 can the DOE 5 in a manually or motor driven driveable device 7 be stored, for example, a revolver unit or a comparable rotating device. By pressing the changer 7 For example, the DOE can be changed to set another suitable geometric arrangement of solder joints.

According to the 1 is the substrate 13 on a translation device 15 , For example, a conveyor belt or a x- / y-displacement table, stored by a drive 16 is driven.

In the process, those on the substrate 13 Trained material weakening areas or perforations preferably formed in a regular, recurring arrangement. During a first process step, in a first region of the substrate 13 simultaneously formed a plurality of material weakening areas or perforations, in the 1 by way of example with the reference numerals 14a - 14c be designated. These material weakening areas or perforations may be on a single substrate, but may also be formed on different substrates formed in the first process step due to the beam splitting into the multiple partial light beams 12a - 12c can be trained simultaneously. Subsequently, the adjustment 15 operates and becomes an adjacent substrate area in the working area of the imaging optics 1 and the DOE 5 driven, in such a way that the partial light rays 12a - 12c in the same way as in the first process step, acting on the respective substrate area to form material weakening areas or perforations in the same geometric arrangement as during the aforementioned first process step. In the 1 these are material weakening areas or perforations formed during the second process step by the reference numbers provided with an apostrophe 14a ' . 14b ' and 14c ' designated. This forms the second process step, which can be repeated as often as desired. Between the process steps, the substrate is thereby moved by an always identical travel path, which is predetermined by the distance between the individual regular arrangements of material weakening regions or perforations on the substrate.

To control the system according to the 1 a control device is provided, for example a CPU (not shown), which in particular the adjusting device 4 , the changing device 7 , the translation device 15 with the assigned drive 16 as well as the laser diode 8th controlled appropriately.

As will be readily apparent to one skilled in the art, the light beam or laser beam is preferably pulsed so as to be in transit of the substrate 13 relative to the imaging optics 1 . 5 to provide a light intensity which is zero or at least below a threshold which would have to be exceeded in order to effect processing of the substrate to form the material weakening areas or perforations.

Further details of the imaging optics 1 are the 2 removable. Between the along the optical axis 11 spaced apart lenses 2 . 3 is a DOE (diffractive optical element) 5 arranged, which the input light beam 10 by light diffraction in the partial light rays shown 12a - 12c Splits. By the imaging properties of the lenses 2 . 3 and / or the DOE 5 become the partial light rays 12a - 12c appropriately focused or imaged. By different diffraction in partial areas 6a - 6c of the DOE 5 become the partial light rays 12a - 12c deflected in suitable directions. According to the 2 can on the DOE 5 several differently designed diffractive optical zones 6a - 6c be provided, which the partial light rays 12a - 12c imprint different intensities, beam cross sections, beam profiles or beam shapes and / or divergences. Those skilled in the art will appreciate a suitable embodiment of the DOE 5 and the diffractive optical zones 6a - 6c be possible without further ado. As will be readily apparent to one skilled in the art, by appropriate expansion of the input light beam 10 and suitable provision of diffractive optical zones 6a - 6c very many partial light rays 12 - 12c be designed to be suitable at the same time.

The inventive method is basically also suitable for substrate processing by simultaneous processing of a substrate at a plurality of sites. For this purpose, in the manner described above, an input light beam in a plurality of partial light beams un distributed according to the 3 on the workpiece 40 a plurality of discrete processing stations 41 form, for example, through holes, blind holes and / or weakening areas. The method is suitable for processing any substrates, for example paper or cardboard sheets, plastic materials or metal sheets. The majority of processing points 41 can according to the 3 along any line course 42 be arranged.

In summary Thus, according to another Another aspect of the present invention is a method for Substrate processing provided, in which method a light beam, In particular, a laser light beam is provided and a Imaging optics images the light beam by light diffraction in such a way and divides it into a plurality of partial light rays, that this one Form a plurality of discrete spots of light that require processing of the respective substrate effect.

there can the light spots through holes, blind holes and / or weakening areas in one by the design of the diffractive optical element form predetermined geometric arrangement.

As a result, for example, suitably extending predetermined breaking lines in plastic caps of motor vehicle airbag modules or in cardboard or paper containers, such as in the EP 0 566 722 B1 described, trained.

As the expert in studying the present application readily can be seen The discrete processing points may also partially overlap. The partial light rays can in any way from a front and / or a back of a carrier the processing points are directed. For this purpose can also in the carrier Through holes be provided or this at least partially transparent be designed to provide optical access to the processing points to enable.

1

imaging optics

2

Input lens / optics

3

Output lens / optics

4

adjustment

5

diffractive optical element

6a. 6c

diffractive optical element / diffractive optical zones

7

changer

8th

light source (Laser diode, LED)

9

optical fiber

10

Input light beam

11

optical axis

12a-12c

Partial light beams

13

Substrate / web material

14a-14c

Perforation / weakening region

15

translation device

16

drive

40

workpiece

41

Perforation / weakening region

42

line

Claims (19)

Method for producing a plurality of material weakening areas or perforations in a substrate ( 13 . 40 ), in which method a light beam ( 10 ), in particular a laser light beam, an imaging optics ( 1 . 5 ) images the light beam in such a way and by light diffraction into a plurality of partial light beams ( 12a - 12c ) states that these are on the substrate ( 13 . 40 ) form a plurality of discrete spots of light in the substrate ( 13 . 40 ) simultaneously a plurality of discrete material weakening areas or perforations ( 14a - 14c . 41 ) train. Method according to Claim 1, in which the imaging optics comprise a diffractive optical element ( 5 ) comprising the light beam ( 10 ) is divided by light diffraction into the plurality of partial light rays. Method according to Claim 2, in which the material weakening regions ( 14a - 14c . 41 ) are formed in a predetermined arrangement and in which the diffractive optical element ( 5 ) corresponding to the predetermined arrangement of material weakening areas or perforations in the partial light beams ( 12a - 12c ) and directed in different directions. Method according to Claim 3, in which the diffractive optical element ( 5 ) a plurality of diffractive optical zones ( 6a - 6c ) in correspondence with the predetermined arrangement of material weakening areas or perforations. Method according to Claim 4, in which the diffractive optical zones ( 6a - 6c ) a different intensity, beam cross-section, shape and / or divergence of the partial light beams ( 12a - 12c ) cause. Method according to Claim 5, in which the shape of the respective weakened region or of the respective perforation ( 14a - 14c . 41 ) directly by the light diffraction properties of the diffractive zone producing the associated light spot ( 6a - 6c ) is given. Method according to one of Claims 2 to 6, in which the light beam ( 10 ) of an optical waveguide ( 9 ) and the imaging optics is an input lens ( 2 ) and an exit lens ( 3 ), wherein by varying the distance (Z1) of the input lens to the optical waveguide and / or the distance (Z2) of the lenses to each other a beam diameter of the light beam ( 10 ) or partial light rays ( 12a - 12c ) is adjusted. Method according to Claim 7, in which the diffractive optical element ( 5 ) between the input lens ( 2 ) and the exit lens ( 3 ) is arranged. Method according to one of the preceding claims, in which the material weakening areas ( 14a - 14c . 41 ) Through holes, blind holes and / or weakening areas whose shapes are formed by the design of the diffractive imaging optics ( 1 . 5 ) are given. Method according to one of the preceding claims, in which the material weakening areas or perforations ( 14a - 14c . 41 ) are formed by thermal melting or ablation of material of the substrate. Method according to one of the preceding claims, in which the substrate ( 13 . 40 ) clocked at the imaging optics ( 1 . 5 ) is moved past. Device for producing a plurality of material weakening areas or perforations in a substrate ( 13 . 40 ), comprising: a holding device ( 15 ) for positioning and / or moving the substrate; a light source ( 8th ), which has a light beam ( 10 ), in particular providing a laser light beam; and an imaging optics ( 1 . 5 ) which images the light beam in such a way and by light diffraction into a plurality of partial light beams ( 12a - 12c ) states that these are on the substrate ( 13 . 40 ) form a plurality of discrete spots of light in the substrate ( 13 . 40 ) simultaneously a plurality of discrete material weakening areas or perforations ( 14a - 14c . 41 ) train. Apparatus according to claim 12, in which the imaging optics comprise a diffractive optical element ( 5 ) comprising the light beam ( 10 ) is divided by light diffraction into the plurality of partial light rays. Device according to Claim 13, in which the diffractive optical element ( 5 ) corresponding to a predetermined arrangement in the partial light beams ( 12a - 12c ) and directed in different directions so that the material weakening areas or perforations ( 14a - 14c . 41 ) are formed in the predetermined arrangement. Device according to Claim 14, in which the diffractive optical element ( 5 ) a plurality of diffractive optical zones ( 6a - 6c ) in correspondence with the predetermined arrangement of material weakening areas or perforations. Device according to Claim 15, in which the diffractive optical zones ( 6a - 6c ) a different intensity, beam cross-section, shape and / or divergence of the partial light beams ( 12a - 12c ) cause. Device according to one of claims 13 to 16, further comprising an optical waveguide ( 9 ), wherein the imaging optics an input lens ( 2 ) and an exit lens ( 3 ), such that by varying the distance (Z1) of the input lens to the optical waveguide and / or the distance (Z2) of the lenses ( 2 . 3 ) to each other a beam diameter of the light beam ( 10 ) or partial light rays ( 12a - 12c ) is adjusted. Device according to Claim 17, in which the diffractive optical element ( 5 ) between the input lens ( 2 ) and the exit lens ( 3 ) is arranged. Device according to one of claims 12 to 18, further comprising a translation device ( 15 ) to the substrate ( 13 . 40 ) clocked at the imaging optics ( 1 . 5 ) to move over.