EP0961688B1 - Device for laser writing on materials - Google Patents

Abstract

A device for inscribing materials has a hand-held device and a support device. The devices have a laser, a refraction unit, a control unit and a power pack consisting of compact, transportable components. The devices are connected to one another by means of a cable or glass fiber connection.

Description

The invention relates to a device for labeling of materials with a laser according to the preamble of claim 1.

From the literature: Walter W. Weinfurtner "Licht writes - laser marking in industry: Basics and fields of application ", Expert-Verlag 1995 (contact &Education; Volume 479) are the principle and the fundamental Structure of a laser marker known from a Solid-state lasers with a laser head, for example there is an optical rail on which the individual optical components thermally and mechanically stable are mounted.

A resonator is arranged in the laser head of the solid-state laser, that of a so-called pump chamber, two mirrors and an acousto-optical switch, a so-called Q switch. There are one in the pumping chamber YAG crystal rod and one or more krypton arc lamps, whose light is imaged in the crystal stick, which on emits light with a predetermined wavelength at both end faces. This light is reflected in by the two mirrors reflects the crystal rod, with the mirror on the rear End of the resonator reflects about 99.9% during the front mirror transmits 12% and thus the working beam forms. The Q-Switch interrupts the work beam up to 40,000 times per second and thus generates power peaks up to 1,000 times the continuous wave or cw laser operation.

The resonator also contains a mechanical switch (Shutter) to interrupt the laser beam and a bracket, in which a fashion aperture is fixed for specific applications to a higher beam quality (e.g. in basic mode) to reach. In a beam expansion, the Laser beam leaving the resonator by a factor of 2 to 10 expanded. The expanded laser beam is in one Deflection unit using two galvanometer mirrors in X and Deflected in the Y direction and via a flat field focusing lens focused on one workpiece.

Other elements of the known laser marker are a Computer for controlling a deflecting device Control device, a Q-switch driver and one Power supply facility. An additional, elaborate Cooling device is provided for cooling the pump chamber.

The known laser marker is a laser system with a Coordinate table, a rotary indexing table with an inlet and outlet tunnel and optionally with a double head arrangement trained as he also as a solid-state laser Material processing, that means for cutting, joining, drilling and the like. Is used with high laser powers, wherein the laser also with a supply cabinet and if necessary to connect with an external heat exchanger is. Such a laser marking system, as they is also the subject of DE 33 18 768 Al, is voluminous built up and can therefore only be used stationary. She also has considerable power requirements and low efficiency, because a lot of the power consumed to ensure proper operation using the Cooling device must be removed.

Such a laser system has considerable dimensions and requires a water connection for cooling the Lasers and a three-phase connection for a power requirement of approx. 8 kW. This laser system requires a lot of maintenance, an ion exchanger because of the water connection and a particle filter are required and high lamp consumption as well as considerable wear of the pump chamber must be accepted.

As can be seen from DE 33 18 768 A1, are for one such a laser marking system also a complex Adjustment device and a number of optical components containing deflection head with a dispersion and collection optics the expansion optics, deflecting mirror and the like are required, the manufacture of the well-known laser marking system and make their maintenance and operation more expensive.

Another laser marking machine is from JP-A-08 001 999 known to have a low power laser (Low-power laser) and a deflection unit. Means this plant is on a light sensitive surface an image of a drum by electrostatic charge generated. To do this, the drum is laser beamed exposed. Expose to the entire surface of the drum to be able to, the drum rotates about its axis of rotation. In addition is the deflection unit in the longitudinal direction of the drum movably arranged along the surface of the drum.

The known device is used in a laser printer, to label paper. For this purpose, toner is applied to the Drum applied to the electrostatically charged only Make the drum stick. Subsequently will use the paper to apply the toner to the paper passed over the drum.

The known device has the disadvantage that it an elaborate and accurate guide is required to ensure adequate Relative movement between the drum and the deflection unit to ensure the entire surface of the Drum can be reached by the laser beam. can. Amongst other things this requires a complex adjustment device to ensure that the laser beam by means of the deflection unit also reached any position on the surface of the drum.

The exact guidance also requires that the known device must be permanently installed in one place. To the well-known To be able to use the device in another location it must first be dismantled, transported to the other location and then reassembled. This requires one enormous effort that causes high costs. Basically the known device can therefore only be used in a stationary manner.

Furthermore, it is not possible with the known device Engraving and lettering on objects using material evaporation to manufacture. This is only in use a high-power laser possible. Would you be one use in the known device, this would have to Consequence that the dimensions of the device are greatly enlarged would.

The object of the present invention is a device for labeling almost any material various ways with a laser with small dimensions and light weight and optimal manageability and greatest possible mobility with low operating costs create.

This object is achieved by the features of Claim 1 solved.

The solution according to the invention creates a mobile device for labeling objects with a solid-state laser, the themselves by small dimensions and light weight as well characterized by a simple structure. The labeling device is both regarding data entry as well with regard to the dispensing head, can be configured variably and can with any additional devices, such as one digital video camera, a CCD imager, a scanner and the like.

By combining several modules Any configuration can be in at least one housing of the marking laser for an application-oriented Structure to be created.

In a first variant of the solution according to the invention the labeling device from a handheld device, the contains a deflection unit and a solid-state laser and which is connected to a portable device via a cable connection which is a control device and a power supply device has, for example an accumulator and / or a power supply. It is also an interface for connecting the control device to a external control and / or input unit provided.

In a second variant of the solution according to the invention the handheld device contains only the deflection unit and is over a fiber optic cable connected to a carrying device that the Solid state laser, the control device and the power supply device contains an interface for connecting the control device to the external one Control and / or input unit is provided.

In a third variant, all modules in can be summarized in a housing that as a handheld device or Tabletop device is designed.

In all three variants, the dimensions are so compact that the handheld device is designed, for example, in the form of a pistol and the carrying device can be accommodated in a housing can with a hip and / or shoulder strap Operator is connectable. With this structure maximum mobility is achieved by the operator permitted, laser inscriptions in any place independently by a supply cabinet or the like.

It is particularly advantageous that the handheld device with a scanning unit, for example a scanner, a video camera or a digital camera. this makes possible for example, that an image is taken with the scanning unit is applied to an object by means of the hand-held device can be. The device is therefore particularly suitable for the management of a warehouse in which goods are stored are provided with a barcode for identification are. For example, the barcodes are Read scanners, to a computer arranged in the hand-held device or forwarded to another, higher-level central computer and processed there. Should the barcode one time need to be changed, the old barcode very easily made unrecognizable or destroyed and the new barcode is applied to the goods.

In an advantageous embodiment of the invention The solution is a recording unit for those to be labeled Objects provided in which a distance measuring device for Delivery of a controlling the focusing of the laser beam Distance measuring signal and a switching device for release of the laser beam with correct positioning of the one to be labeled Object are arranged. Alternatively, it is a mechanical stop for static focusing of the Laser beam provided.

The arrangement of a recording unit for labeling Objects ensures a safe positioning of the labeling object in the focal plane of the laser beam as well as safe handling of the labeling device.

Alternatively or in addition to this is to adjust the focus distance a lens system, for example a lens system an autofocus camera.

To create a mobile unit as possible, at-r preferred embodiment, the control device wireless via a radio, infrared or ultrasound transmission and Receiver unit with an external control and / or input unit connected.

Preferably, the control device as well as, if applicable Parts of the power supply device from film circuits built using SMD techniques and are therefore particularly suitable for a compact Structure and housing in component housings, which on Body of the operator can be worn.

To ensure minimum dimensions and maximum Efficiency, the laser consists of one with one Laser diode longitudinally pumped solid-state laser, the one Laser bench with a laser crystal, a Q switch, one highly reflective resonator mirror and a decoupling mirror contains, preferably the laser crystal none or the lowest possible stress birefringence and also a long fluorescence life with the lowest possible Has dimensions.

The solid-state laser is optionally available with an active Q-switch, i.e. with an optoacoustic crystal or with a passive Q-switch and a laser diode, which is operated in pulsed mode, among other things.

The laser diode preferably has the highest possible Efficiency. To keep it stable, the Laser diode with a cooling element, for example with a Peltier element, chilled. It is envisaged both Laser diode driver as well as the Peltier driver either in Handheld device or to be arranged in the carrying device. It is under "Driver" the corresponding supply board of a component Roger that.

The individual laser components are preferably very arranged compactly to each other to a minimum dimension to achieve, which ensures mobile handling.

In particular, a short resonator geometry is used so that very short laser pulses and thus a high peak pulse power be generated. To be as compact as possible To get an arrangement with small external dimensions, the short resonator geometry preferably by a folded Beam path by means of a corresponding mirror arrangement, for example two arranged at 45 ° to the beam axis Mirror, provided.

In addition, the device also has optics Beam expansion, preferably by means of two lenses. As an alternative or in addition to this, the beam expansion by another, consisting of at least two mirrors Mirror system provided that preferably also a folded beam path through multiple Has reflection.

In a preferred embodiment of the invention are polarizers provided to generate polarized laser light. However, this light can also pass through the laser crystal be generated yourself. In this way it is possible to Diffraction efficiency of an acousto-optical quality switching element to increase. This is particularly advantageous because since the device according to the invention preferably at least optics with high diffraction efficiency, in particular a crystal, which has the laser process in the resonator with low radio frequency power input at the same time interrupts efficiently.

To further increase the compactness and the weight minimize, are the elements of the device according to the invention made of fiber composite materials, ceramic or plastic manufactured. In addition, the optics are glued assembled and / or attached.

To provide a fast, accurate and inexpensive drive for to obtain the deflection unit, it is a preferred one Embodiment provided as the motor of the drive unit, with which the deflection unit is adjusted, a drive unit a read / write head of a data memory, in particular a magnetic or optical data storage, to provide. However, the invention is not based on this Type of drive unit restricted. Rather, too conventional drive units, for example galvanometer scanners, act as drive units for the deflection unit become.

Fig. 1 -

ein schematisches Blockschaltbild einer Handlaser-Beschriftungsvorrichtung mit in einem Traggerät angeordnetem Festkörperlaser;

Fig. 2 -

ein schematisches Blockschaltbild einer Handlaser-Beschriftungsvorrichtung mit im Handgerät angeordnetem Festkörperlaser;

Fig. 3 -

eine schematische Darstellung einer Bedienungsperson mit Handgerät und an einem Hüftgurt angeordnetem Traggerät;

Fig. 4 -

ein schematisches Blockschaltbild einer Handlaser-Beschriftungsvorrichtung mit drahtloser Signaleingabe; und

Fig. 5 -

mögliche Spiegelanordnungen zur Verkürzung der Resonatorlänge.

The idea on which the invention is based will be explained in more detail with reference to exemplary embodiments shown in the drawing. Show it:

Fig. 1 -

a schematic block diagram of a hand-held laser marking device with a solid-state laser arranged in a carrying device;

Fig. 2 -

a schematic block diagram of a hand laser marking device with a solid-state laser arranged in the hand-held device;

Fig. 3 -

a schematic representation of an operator with a handheld device and a carrying device arranged on a hip belt;

Fig. 4 -

is a schematic block diagram of a hand laser marking device with wireless signal input; and

Fig. 5 -

possible mirror arrangements to shorten the resonator length.

The schematic shown in Figures 1 and 2 Block diagrams of devices for labeling objects with a solid-state laser are made up of one different groupings of similar components together. They can be illustrated by further examples supplement, which consist of similar groups, for example the summary of all assemblies in a laser marking device provided with a housing, that in the form of a tabletop device as a mobile labeling station is trained.

The term "labeling" includes every type of object marking understood, for example the mistake with any font, but also the creation of Picture elements and three-dimensional engravings. Farther the term "labeling" is used to remove labeling elements by removing surface layers (e.g. barcodes, graffiti, etc.) and the like.

FIG. 1 shows the block diagram of a compact hand laser marking device, coming from a handheld device 1 and a one- or two-part carrying device 2. The handheld device 1 contains in this embodiment a deflection unit 7 in front of the object to be labeled is placed or with a recording unit for recording and adjustment of the object to be labeled can be connected is. The hand-held device 1 also contains a scanning unit 8, for example from a scanner, a CCD image converter or a digital video camera.

The carrying device 2 contains a control device 21, a Solid-state laser 4 and a power supply device 22, which is connected to the units of the carrying device. The Control device 21 has a microprocessor 11, a RF generator 12, a read / write memory or a different storage medium 13, signal amplifier 200 for Amplification of the control signals for those in the deflection unit 7 mirror adjustments (galvanometer scanner) and an input and monitoring unit 14 on, while the solid-state laser 4 from a laser bank 5 (or another mechanically stable construction of the Laser components) and a laser diode 6. The Laser bank 5 contains a longitudinal or transverse pumped laser crystal 50, a Q switch 51 (active or passive Q-switch) and a highly reflective resonator mirror 52 and a coupling mirror 53.

Is used to drive the mirror adjustments in the deflection unit 7 a drive unit of a read / write head Data storage, in particular a magnetic data storage, used, the signal amplifiers 200 may omitted because the drive unit of the read / write head is on already has such signal amplifiers.

The output of the solid-state laser 4 is via a glass fiber cable 17 connected to the deflection unit 7. The fiber optic cable 17 can be combined with an electrical cable the connecting lines 31 between the microprocessor 11 and the scanning unit 8, the microprocessor 11 and the Deflection unit 7 and a power supply cable for connection the power supply device 22 with the handheld device 1 contains. When the control device is arranged separately 21 and the solid-state laser 4 from the power supply device 22, for example in different housings or parts of a housing is an additional power supply cable between the control device 21 and the solid-state laser 4 on the one hand and the power supply device 22 on the other hand.

The power supply device 22 is composed of an accumulator 9 and a power supply 10 together. In this Power supply device is also the driver of one Peltier element, not shown, provided for cooling arranged.

An external control and monitoring unit is via an interface 15 3 with the microprocessor 11 of the control device 21 connected to input any data. Instead of one that can be connected to the control device 21 via a cable external control and monitoring unit 3 is also a wireless transmission possible, so that instead of one Plug connection as interface 15 an electromagnetic electro-optical or electro-acoustic transmission of Signals between an external control and monitoring unit and the control device 21 can be provided can. Alternatively, direct data entry, for example done via a miniature laptop.

The solid-state laser 4 consists of a laser diode 6 longitudinally or transversely pumped solid-state lasers, its laser bank 5 to increase efficiency and thus maximum power output contains no polarizers. As Laser crystal 50 becomes a crystal with no or lowest possible voltage birefringence used, the has minimal dimensions. In conjunction with a low power output of an RF generator, its RF power for example less than or equal to 2 to 4 watts, and an optimal choice of the laser crystal 50 can the laser bench 5 can be built extremely compact, because at low Only a small amount of heat is dissipated.

The operation of the laser bank 5 can optionally be continuous pumped with an active Q-switch (RF source) below Use of an optoacoustic crystal or with a passive Q-switch.

A further increase in the compactness of the invention Labeling device can by using a folded beam path with mirrors and the like in the deflection unit 7 or in the laser head, so that overall a portable laser marking device with the lowest possible outer dimensions and weight is created.

A variant shown in Figure 2 as a block diagram a laser marking device shows the summary of the solid-state laser 4 with the deflection unit 7 in a handheld device 1 and the summary of the control device 21 with the power supply device 22 in one Carrier 2 together.

The control and supply device is electrical Line 18 connected to the handheld device 1. A further connection is via an interface 15 with an external Control and monitoring unit 3 and with one Scanning unit 8 is provided, which is analogous to the embodiment 1 from a digital (video) camera, a CCD image converter or a scanner can exist. The Scanning unit 8 can also be analogous to the arrangement according to FIG Figure 1 can be coupled with the handheld device 1, so that the Handheld device 1 can also be used for signal recording. About that in addition, two are not shown in the carrying device 2 Signal amplifier for amplifying the control signals for the mirror adjustments located in the deflection unit 7 arranged.

FIG. 3 shows the use in a schematic sketch the hand laser marking device according to the invention and their composition from a handheld device 1 and a Carrier 2, which in this embodiment has a hip or lap belt 16 connected around an operator's waist is attachable. Alternative types of mounting the Carriers are a backpack shape with on the back too fastening carrying device as well as lateral (belt) fastenings.

The connection between the handheld device 1 and the carrying device 2 is established via a cable connection 17, 18 optionally from a fiber optic cable and / or an electrical one Connection cable exists.

The handheld device 1 can be used, for example, with a video camera 80 are coupled with the recordings for signal input can be made by objects or people who via the signal processing of the control device for control the solid-state laser and the deflection unit become.

The handheld device 1 contains in a module arrangement according to 1 shows the deflection unit 7 and, if appropriate, the scanning unit 8 or 80, while in this embodiment the carrying device 2 the solid-state laser, the control device and power supply device contains.

In a module arrangement according to FIG Handheld device 1, the laser arrangement and the deflection unit 7 possibly in connection with a scanning element while the Carrier 2, the control device and the power supply device contains. On the front of the carrying device 2 is a connection 15 of the support device 2 for the connection 17, 18 with the handheld device as well as for an external control and Monitoring unit provided.

Contains to reduce the dimensions of the carrying device 2 this largely film circuits in connection with SMD components, so that the carrying device 2 comfortably around the An operator's hip is to be laid. Alternatively can also use multilayer arrangements instead of the film connections can be provided with SMD components.

The variant shown in Figure 4 as a block diagram a hand laser marking device shows the summary a semiconductor laser with a laser diode 6 and a collimator optics 55 and the control device a processor 11 and a memory element 13 in one Carrying device on. The power supply device 9 (accumulator) is either coupled to the carrying device or as separate carrying device attached.

In this embodiment, the hand-held device 1 contains a deflection unit 7 with two deflecting mirrors. Furthermore, with the handheld device 1 has a scanning unit 8 analogous to the embodiment be connected according to Figure 1.

The signal input can be via the scanning unit as well also via a wireless connection from an external Data input device 3 take place. For this, a radio, infrared or ultrasound transmitter and receiver unit provided, which with a transmitting and receiving element 19 on the Side of the control device is connected. A corresponding one Transmitting and receiving element is on the external Control device 3 is provided.

FIGS. 5a to 5d each show the resonator that is made of the Kristall 50 and the 99.9% reflective mirror 52 and the exit mirror 53, which is about 88% of Light reflects and transmits 12% of the light.

An arrangement of the resonator elements that has been used up to now is shown in Fig. 5a. The two mirrors 52 and 53 and the crystal 50 are arranged one behind the other in such a way that the laser beam straight from the Exit mirror 53 exits.

To make the hand laser marking device even more compact make, the resonator according to Fig. 5b next to the already called resonator elements on a mirror 100, which in is arranged at an angle of 45 ° to the beam axis. By this arrangement the laser beam is deflected by 90 °, before exiting through exit mirror 53. Through the Redirection gives you a folded beam path that a more compact design of the resonator and thus one further increase in the compactness of the hand laser marking device enables.

As shown in Fig. 5c, this effect is further enhanced in which the laser beam deflected according to FIG. 5b again by 90 ° through another, at an angle of 45 ° to the Beam axis arranged mirror 101 is deflected before he exits through the mirror 53.

The folded beam path caused by this deflection enables such a compact construction of the resonator, that the resonator length over conventional resonators and significantly reduced the overall external dimensions of the device becomes.

Another embodiment according to FIG. 5c shows 5d. At this embodiment are in the beam path between the two mirrors 100 and 101 another Q switch 51 (active or passive Q-switch) and after mirror 53 Shutter 103, which is used to release the laser beam when correct Positioning of the object to be labeled, arranged. Behind the shutter 103 is one of two mirrors 301 and 302 existing mirror system 300 for expansion arranged of the laser beam. The one in the mirror system 300 incident laser beam is only after several Reflection on the two mirrors 301 and 302 coupled out again.

Claims (26)

1. A device for inscribing materials with a laser (4), a refraction unit (7), a control unit (21) and a power pack (22), whereby the laser (4), the refraction unit (7), the control unit (21) and the power pack (22) consist of compact, transportable components
   characterised in that
   several of the components are brought together in a hand-held device (1).
2. A device according to Claim 1 characterised in that the hand-held device (1) contains the refraction unit (7) and the laser (4), and the device has a support device (2) containing the control unit (21) and the power pack (22) as well as an interface (15) for connecting the control unit (21) to an external control and / or input unit (3).
3. A device according to Claim 1 characterised in that the hand-held device (1) contains the refraction unit (7), whereby this hand-held device (1) is connected by means of a glass fibre cable (17) to a support device (2), which has the laser (4), the control unit (21) and the power pack (22) as well as an interface (15) for connecting the control unit (21) to an external control and / or input unit (3).
4. A device according to Claim 1 characterised in that all the components are brought together in the hand-held device.
5. A device according to one of the Claims 2 to 4 characterised in that the hand-held device (1) is connected to a sensor unit (8), in particular to a scanner, video camera, digital camera or similar.
6. A device according to at least one of the preceding claims characterised in that the hand-held device (1) is in a form suited to the anatomy of the hand.
7. A device according to at least one of the preceding claims characterised in that the support device (2) can preferably be connected to a waist and / or shoulder strap (16).
8. A device according to at least one of the preceding claims characterised in that there is a recording unit for objects to be inscribed, whereby this recording unit has a distance-measuring device for emitting a distance reading which controls the focusing of the laser beam, and a switching device for releasing the laser beam when the object to be inscribed is correctly positioned.
9. A device according to at least one of the preceding claims characterised in that for the purpose of adjusting the focus distance, there is a lens system, in particular a lens system of an auto-focus camera.
10. A device according to at least one of the preceding claims characterised in that there is a recording unit with a mechanical catch for objects to be inscribed.
11. A device according to at least one of the preceding claims characterised in that the control unit (21) is connected to an external control and / or input unit wirelessly by means of a radio, infra-red or ultrasound transceiver.
12. A device according to at least one of the preceding claims characterised in that at least the control unit (21) and / or the power pack (22) consists of foil circuits with components secured in SMD technology.
13. A device according to at least one of the preceding claims characterised in that the laser (4) consists of a solid-state laser which is longitudinally or transversally pumped with a laser diode (6), whereby the pump volume thereof preferably corresponds to the basic mode volume of the material to be pumped, and further characterised in that the laser (4) has a laser bank (5) with a laser crystal (50), a Q-switch (51), a highly-reflecting resonator reflector (52) and an output reflector (53).
14. A device according to Claim 13 characterised in that the laser crystal (50) does not have tension birefringence / its tension birefringence is as low as possible, and that the laser crystal has high fluorescence durability as well as having the smallest possible dimensions.
15. A device according to Claim 13 or Claim 14 characterised by a solid-state laser (4) which is continuously pumped and is Q-switched / modulated by means of an opto-acoustic crystal, FTIR crystal or similar.
16. A device according to Claim 13 or Claim 14 characterised in that there is a solid-state laser (4) driven by means of a passive Q-switch component and a continuous wave or pulse-controlled laser diode (6).
17. A device according to at least one of the preceding claims characterised in that the efficiency rate of the laser diode (6) is as high as possible.
18. A device according to at least one of the preceding claims characterised in that the device for cooling the laser diode has a cooling component, in particular a Peltier component.
19. A device according to Claim 18 characterised in that both the laser diode driver and the Peltier driver are positioned either in the hand-held device or in the support device.
20. A device according to at least one of the preceding claims characterised in that there is a compact configuration of the individual laser components including a resonator length which is as short as possible, in particular by means of a folded optical train.
21. A device according to at least one of the preceding claims characterised by a reflector system as a widening lens system, in particular with a reflector configuration with a folded optical train, and / or a widening lens system by means of two lenses.
22. A device according to at least one of the preceding claims characterised in that the reflector configuration has at least two reflectors positioned at 45° to the axis of the beam.
23. A device according to at least one of the preceding claims characterised by optical components or by the laser crystal for generating polarised light, in order to increase the diffraction efficiency rate of the acoustic-optical Q-switching component.
24. A device according to at least one of the preceding claims characterised in that there is at least one lens system with a high diffraction efficiency rate, in particular a crystal, whereby this lens system efficiently interrupts the laser process in the resonator at the same time as there is low high-frequency power input.
25. A device according to at least one of the preceding claims characterised by components made from fibre-reinforced material, ceramics and / or synthetic material, as well as by stuck-on components.
26. A device according to at least one of the preceding claims characterised in that the motor of the drive unit, by means of which the refraction unit is adjusted, is constituted by the drive unit of a read / write head of a data storage unit, in particular a magnetic or optical data storage unit.

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