JP4957474B2 - Laser marking device - Google Patents

Description

  The present invention relates to a laser marking device, and more particularly to a laser marking device using an optical fiber amplifier.

  Conventionally, a laser marking device has been provided as a device for printing desired information on the surface of an object. Generally, a laser marking device includes a laser light source that performs pulse oscillation. A solid-state laser is often used as the laser light source.

In a solid-state laser, a resonator is configured by providing a total reflection mirror and a partial transmission mirror at both ends of a laser medium such as a YAG or YVO ₄ crystal. A Q switch is disposed between the partially transmissive mirror and the laser medium, and a light source for exciting the medium is provided around the laser medium.

  When the laser medium is excited by the excitation light source with the Q switch in the light blocking state, energy is accumulated inside the resonator. When the Q switch is changed to the light transmission state, the laser light generated in the laser medium reciprocates between the total reflection mirror and the partial transmission mirror and is amplified by the energy accumulated in the laser medium. Then, part of the light passes through the partial reflection mirror and is emitted to the outside.

  The emitted laser light (light pulse) is scanned two-dimensionally by a scanning mechanism such as a galvano scanner. The surface of the object to be printed is physically processed by laser light. The surface of the object to be printed is melted or scraped by the laser beam. This makes it possible to print information composed of characters, figures, etc. on the surface of the object.

  In a solid-state laser, since the mirrors are disposed at both ends of the laser medium, the size thereof tends to increase. For this reason, when a laser marking device including a solid-state laser is installed in a production line, the entire production line may be increased in size by the installation space.

  As a laser marking device capable of solving such a problem, a laser marking device including an optical fiber laser has been proposed. An optical fiber laser generally includes an optical fiber having a core portion doped with a rare earth element and a pumping light source for exciting the rare earth element. For example, by rotating the optical fiber around the bobbin, it becomes possible to reduce the size while ensuring a sufficient optical path in the laser medium.

  As a conventional laser marking apparatus equipped with an optical fiber laser, for example, a laser marking apparatus has been proposed in which an optical fiber is preliminarily excited when marking is not performed and the power of excitation light is increased when performing a marking operation. (See Patent Document 1).

  Further, there has been proposed a laser marking device that changes the power of laser light output from an optical fiber by changing the power of signal light incident on the optical fiber (see Patent Document 2).

An optical fiber laser using a solid laser as a light source for generating laser light incident on an optical fiber has been proposed (see Non-Patent Document 1).
Japanese Patent No. 3411852 US Pat. No. 6,275,250 Fabio Di Teodoro and Christopher D Brooks, “Multistage Yb-doped fiber generating megawatt peak-power, sub TN LS 30, NO. 24, p. 3299-3301

  The optical fiber laser described in Patent Document 3 includes a Q switch in the same manner as the solid-state laser described above. When a laser light source including a Q switch repeatedly emits an optical pulse, the repetition frequency of the optical pulse depends on the operable frequency of the Q switch.

  The Q switch includes an AO element (acousto-optic element) type or an EO (electro-optic) modulator type. The upper limit of the operable frequency of these Q switches is generally about 200 kHz.

  For example, in a production line, the higher the printing speed, the shorter the time required for printing per product, which is preferable. In order to increase the printing speed, it is necessary to increase the scanning speed of the laser beam. However, when the repetition frequency of the light pulses is low and the scanning speed of the laser light is high, the number of light pulses emitted when printing a certain character is reduced. In this case, there arises a problem relating to the print quality such that the character line is interrupted.

  In the case of a laser light source provided with a Q switch, the pulse width of an optical pulse emitted from the laser light source is determined by the power inside the resonator and the length of the resonator. Further, the repetition frequency of the light pulse changes in conjunction with the pulse width of the light pulse. That is, in the case of a laser light source provided with a Q switch, the repetition frequency and pulse width of an optical pulse cannot be controlled independently of each other.

  When processing the surface of an object to be printed with laser light, the degree of processing of the surface of the object to be printed (the degree of discoloration, the size of the portion scraped by the laser light, etc.) differs depending on the peak value of the energy of the light pulse . The peak value of the energy of the light pulse can be controlled by controlling the pulse width. However, in the case of a laser light source provided with a Q switch, if the pulse width is changed, the repetition frequency of the optical pulse also changes, so the degree of freedom in setting the pulse width is reduced.

  On the other hand, as in the technique disclosed in Patent Document 2, it is conceivable to use light from a semiconductor laser as signal light. In this case, it is considered that the pulse width and repetition frequency of the optical pulse emitted from the optical fiber laser can be controlled by controlling the current applied to the semiconductor laser.

  Here, various materials such as metal, resin, glass, and ceramic can be considered as the material of the printing object. For this reason, the processing method of the printing target object by a laser beam may differ for every material. That is, the light pulse conditions may differ depending on the material of the printing object. However, Patent Document 2 does not disclose that the condition of the light pulse is determined in consideration of the material of the printing object.

  Therefore, when using the laser marking device disclosed in Patent Document 2, the user must determine the light pulse condition every time the material of the printing object is different. However, the user must perform a number of tests until the light pulse conditions are determined. For this reason, a user's burden increases.

  The objective of this invention is providing the laser marking apparatus which can raise the utility value for a user.

  In summary, the present invention is a laser marking device, which includes a semiconductor laser, a drive unit that drives the semiconductor laser in a pulsed manner, and an optical amplification component that amplifies the optical pulse from the semiconductor laser in an excited state. An optical fiber that outputs amplified light, which is an optical pulse amplified by an optical amplification component in an excited state, from the other end surface, and excitation light for bringing the optical amplification component into an excited state to the optical fiber. By repeating the amplification light by controlling the driving device by receiving the excitation light source to be incident, the scanning mechanism for scanning the amplified light, and the print setting information including the printing speed indicating the scanning amount per unit time of the amplified light. A control unit for controlling the frequency and the pulse width. The control unit stores the correspondence relationship between the repetition frequency and the pulse width in advance, and controls the repetition frequency and the pulse width based on the print setting information and the correspondence relationship.

  Preferably, the control unit stores a correlation between the repetition frequency and the pulse width that is determined so that the pulse width becomes shorter as the repetition frequency becomes higher.

  More preferably, the print setting information further includes information on the material of the print object. The control unit stores the correspondence for each material of the print target and determines the correspondence for controlling the repetition frequency and the pulse width based on the print setting information.

  More preferably, the laser marking apparatus has a test mode for performing a print test as an operation mode. In the test mode, the control unit maintains the pulse width at a value determined based on the print setting information and the correspondence, and changes the repetition frequency within a range including the value determined by the pulse width and the correspondence. Perform a print test.

  More preferably, the laser marking apparatus has a test mode for performing a print test as an operation mode. In the test mode, the control unit maintains the repetition frequency at a value determined based on the print setting information and the correspondence, and changes the pulse width within a range including the value determined by the repetition frequency and the correspondence. Perform a print test.

  More preferably, the correlation is a relationship between the repetition frequency and the pulse width when the average power of the pulsed light is constant.

  Preferably, the laser marking apparatus has a test mode for performing a print test as an operation mode. The correspondence relationship is a relationship in which the pulse width is constant with respect to the repetition frequency. In the test mode, the control unit performs a print test by changing the repetition frequency among a plurality of values according to the correspondence relationship.

  Preferably, the laser marking apparatus has a test mode for performing a print test as an operation mode. The correspondence relationship is a relationship in which the repetition frequency is constant with respect to the pulse width. In the test mode, the control unit performs a print test by changing the pulse width between a plurality of values according to the correspondence relationship.

  Preferably, the laser marking apparatus has a test mode for performing a print test as an operation mode. The correspondence relationship includes a plurality of combinations of repetition frequency and pulse width. In the test mode, the control unit selects a combination corresponding to the print setting information from a plurality of combinations and performs a print test.

  More preferably, the laser marking device further includes an input unit for the user to input print setting information. The print setting information further includes information for setting at least one of the repetition frequency and the pulse width input by the user.

  Preferably, the laser marking apparatus has a test mode for performing a print test as an operation mode. In the test mode, the control unit prints a test pattern by controlling the scanning mechanism, and changes the repetition frequency according to the correspondence.

  More preferably, the control unit further prints information indicating the repetition frequency by controlling the scanning mechanism.

  Preferably, the laser marking apparatus has a test mode for performing a print test as an operation mode. In the test mode, the control unit prints a test pattern by controlling the scanning mechanism and changes the pulse width according to the correspondence.

  More preferably, the control unit further prints information indicating the pulse width by controlling the scanning mechanism.

  According to the laser marking device of the present invention, it is possible to increase the utility value for the user.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

[Configuration of laser marking device]
FIG. 1 is a diagram showing the configuration of the laser marking apparatus of the present embodiment. Referring to FIG. 1, laser marking apparatus 100 </ b> A includes optical fiber 1, semiconductor lasers 2 and 3, isolators 4 and 6, and coupler 5.

  The optical fiber 1 has a core to which a rare earth element as an optical amplification component is added. The kind of rare earth element is not particularly limited, and examples thereof include Er (erbium), Yb (ytterbium), and Nd (neodymium).

  In general, in an optical fiber, a clad having a refractive index slightly lower than that of the core (for example, about 1% lower) is provided around the core. The optical fiber 1 is a double clad fiber in which a clad is provided twice around a core. The refractive index of the cladding close to the core (first cladding) is lower than the refractive index of the core. The refractive index of the clad far from the core (second clad) is lower than the refractive index of the first clad.

  The optical fiber 1 may be a single clad fiber in which a single clad is provided around the core. However, by using a double clad fiber for the optical fiber 1, higher power light can be output from the optical fiber 1.

  The semiconductor laser 2 emits seed light. The wavelength of the seed light is, for example, 1062 ± 2 nm. The seed light output from the semiconductor laser 2 passes through the isolator 4.

  The isolator 4 realizes a function of transmitting only light in one direction and blocking light incident in the opposite direction to the light. In the present embodiment, the isolator 4 blocks the return light from the optical fiber 1. This can prevent light from entering the semiconductor laser 2. When light is incident on the semiconductor laser 2, the semiconductor laser 2 may be damaged, but such a problem can be prevented by the isolator 4.

  The semiconductor laser 3 emits excitation light for exciting the rare earth element added to the core of the optical fiber 1. The coupler 5 couples the light from the semiconductor laser 2 and the light from the semiconductor laser 3 to enter the optical fiber 1.

  Light from the semiconductor laser 2 propagates through the core of the optical fiber 1 (double clad fiber). The light from the semiconductor laser 3 enters the first cladding of the optical fiber 1 (double cladding fiber). The light from the semiconductor laser 3 propagates through the first clad while being repeatedly reflected at the interface between the first clad and the second clad. A part of the light propagating through the first cladding is absorbed by the rare earth element when passing through the core. Thereby, a rare earth element will be in an excited state. Further, when light from the semiconductor laser 2 enters the core, the light is amplified by stimulated emission by the excited rare earth element.

  In the case of a double-clad fiber, the amount of excitation light absorbed by the rare earth element can be increased by confining the excitation light in the first cladding. Thereby, the power of the light output from the optical fiber 1 can be increased.

  The optical fiber 1 is wound around a bobbin (not shown) several times. Thereby, the installation space of the optical fiber 1 can be made small.

  The isolator 6 allows the light pulse output from the optical fiber 1 to pass therethrough and blocks light returning to the optical fiber 1.

  The laser marking device 100 </ b> A further includes a band pass filter 7, an optical fiber 8, semiconductor lasers 9 </ b> A to 9 </ b> D, a coupler 10, an isolator 11, and an end cap 12.

  The band pass filter 7 allows light in a predetermined wavelength band to pass. Specifically, the “predetermined wavelength band” is a wavelength band including the peak wavelength of the optical pulse output from the optical fiber 1. That is, the band pass filter 7 realizes a function of removing unnecessary light.

  The optical fiber 8 is a double clad fiber like the optical fiber 1 and includes a core to which a rare earth element is added.

  The semiconductor lasers 9A to 9D emit excitation light for exciting the rare earth element. In the present embodiment, the number of excitation light sources is four, but is not particularly limited to this value.

  The coupler 10 combines the light pulse that has passed through the bandpass filter 7 and the light from the semiconductor lasers 9 </ b> A to 9 </ b> D to enter the optical fiber 8. The light pulse that has passed through the bandpass filter 7 propagates through the core of the double clad fiber (optical fiber 8). The lights of the semiconductor lasers 9A to 9D are incident on the first clad of the double clad fiber (optical fiber 8). Similar to the optical fiber 1, light propagating through the core is amplified by stimulated emission of rare earth elements. The isolator 11 allows an optical pulse output from the optical fiber 8 to pass and blocks light returning to the optical fiber 8.

  The light pulse that has passed through the isolator 11 is output to the atmosphere from the end face of the optical fiber attached to the isolator 11. The end cap 12 is provided to prevent damage that occurs at the interface between the end face of the optical fiber and the atmosphere when an optical pulse having a high peak power is output from the optical fiber to the atmosphere.

  Hereinafter, the light pulse output from the end cap 12 is also referred to as “laser light”.

  The laser marking device 100 </ b> A further includes a collimator lens 13, a scanning mechanism 14, and an fθ lens 15.

  The collimator lens 13 adjusts the diameter of the laser beam output from the end cap 12 to a predetermined size. The laser light that has passed through the collimator lens 13 enters the scanning mechanism 14.

  The scanning mechanism 14 includes a galvano scanner (not shown). The scanning mechanism 14 scans incident light two-dimensionally. The fθ lens 15 collects the light and irradiates the surface of the print target 50. Information consisting of characters, figures, and the like is printed (marked) on the surface of the print object 50 by the laser light L condensed by the fθ lens 15.

  The laser marking device 100A further includes a laser marker control unit 20A, an input unit 25, a pulse driving unit 30, drivers 33, 34A to 34D, and 35, and temperature controllers 41 to 44, 45A to 45D. The pulse driving unit 30 includes a pulse generator 31 and a driver 32.

  The pulse driving unit 30 applies a pulsed current to the semiconductor laser 2 to oscillate the semiconductor laser. The laser marker control unit 20 </ b> A controls the pulse width and repetition frequency of the current pulse output from the pulse driving unit 30 by controlling the pulse driving unit 30. Thereby, the repetition frequency and pulse width of the seed light (light pulse) emitted from the semiconductor laser 2 are controlled. The repetition frequency of the optical pulse is determined to an appropriate value in the range of, for example, 10 (kHz) to 1 (MHz), and the pulse width is determined to be an appropriate value in the range of, for example, 5 to 100 (ns).

  Drivers 33 and 34A to 34D drive semiconductor lasers 3 and 9A to 9D, respectively. The laser marker control unit 20A controls the drivers 33 and 34A to 34D. The laser marker control unit 20A controls the operation start and operation end of the drivers 33 and 34A to 34D.

  The driver 35 drives the scanning mechanism 14. The laser marker control unit 20 </ b> A controls the driver 35. Thereby, the scanning mechanism 14 can scan the laser beam L in the X direction and the Y direction.

  The temperature controllers 41 and 42 keep the temperature of the semiconductor lasers 2 and 3 constant. The temperature controllers 43 and 44 keep the temperature of the isolator 6 and the temperature of the bandpass filter 7 constant. The temperature controllers 45A to 45D keep the temperatures of the semiconductor lasers 9A to 9D constant.

  The laser marker control unit 20A controls the temperature controllers 41 to 44 and 45A to 45D. For example, the laser marker control unit 20A gives a temperature set value to each of the temperature controllers 41 to 44 and 45A to 45D. Each temperature controller performs temperature control according to the set value.

  The input unit 25 receives print setting information input by the user and transmits the print setting information to the laser marker control unit 20A. The laser marker control unit 20A controls the repetition frequency and pulse width of the seed light output from the semiconductor laser 2 by controlling the pulse driving unit 30 based on the print setting information.

  The repetition frequency and pulse width of the optical pulse output from the optical fiber 8 depend on the repetition frequency and pulse width of the optical pulse emitted from the semiconductor laser 2, respectively. In short, the laser marker control unit 20A controls the repetition frequency and pulse width of the optical pulse output from the optical fiber 8 based on the print setting information.

  The laser marker control unit 20A is realized by, for example, a personal computer that executes a predetermined program. The input unit 25 is not particularly limited as long as the user can input print setting information. For example, a mouse, a keyboard, a touch panel, or the like can be used.

  In the present embodiment, in order to obtain a high-power optical pulse (amplified light) from the optical fiber, the light from the semiconductor laser 2 is passed through the two optical fibers. As a result, two-stage optical amplification is performed. However, in the present invention, the number of optical fibers is not particularly limited.

  FIG. 2 is a functional block diagram of the laser marker control unit 20A of FIG. Referring to FIG. 2, laser marker control unit 20 </ b> A includes a print control unit 21 </ b> A, an excitation light source control unit 22, and a temperature control unit 23.

  The print control unit 21 </ b> A receives print setting information from the input unit 25. The print control unit 21 </ b> A controls the pulse driving unit 30 based on the print setting information and also controls the driver 35 for driving the scanning mechanism 14.

  The excitation light source controller 22 controls a driver for the excitation light source. Specifically, the excitation light source control unit 22 controls drivers 33 and 34A to 34D for driving the semiconductor lasers 3 and 9A to 9D, respectively.

The temperature control unit 23 controls the temperature controllers 42 to 44 and 45A to 45D.
The print control unit 21A receives a trigger signal from the input unit 25. The trigger signal is sent from the input unit 25 to the print control unit 21 </ b> A when the user operates the input unit 25. The print control unit 21A starts control of the pulse driving unit 30 and the scanning mechanism 14 in response to the trigger signal.

  The operation start timings of the excitation light source control unit 22 and the temperature control unit 23 are not particularly limited. For example, the excitation light source control unit 22 may start the operation in response to an instruction from the print control unit 21A, a trigger signal, or power-on to the laser marker control unit 20A. The same applies to the temperature control unit 23.

  FIG. 3 is a diagram illustrating an example of print setting information input to the print control unit 21A. Referring to FIG. 3, items of print setting information include print mode, print data, print speed, print start position, and the like. The print mode means an operation mode when operating the laser marking apparatus 100A. For example, the print mode includes a test mode for performing test printing and a normal mode for printing print data under fixed printing conditions.

  The print data means data printed on the surface of a print object, and is data composed of characters, figures, symbols, and the like, for example.

  The printing speed is a scanning amount of the laser beam of the scanning mechanism 14 per unit time (for example, 1 second).

  The print start position indicates the X coordinate and the Y coordinate of the print start position in the XY coordinate system defined by the laser marking device 100A.

  FIG. 4 is a flowchart showing processing executed by the print control unit 21A. This process is called from the main routine and executed when, for example, a predetermined condition is satisfied or at regular intervals.

  Referring to FIG. 4, first, print setting information is input to print control unit 21A (step S1). Next, the print controller 21A sets the repetition frequency and pulse width of the optical pulse output from the optical fiber 8 based on a predetermined relationship stored in advance (step S2).

  FIG. 5 is a diagram for explaining the average power, pulse width, and repetition frequency of an optical pulse. Referring to FIG. 5, the repetition frequency f is represented by the reciprocal of the period of the optical pulse. The time integral value of the optical pulse (area of the area shown by oblique lines) is assumed to be energy Pe per pulse. The average power Pd is obtained by multiplying the energy Pe per pulse by the repetition frequency f. Furthermore, when the full width at half maximum of the optical pulse is τ, the peak power Pp of the optical pulse is expressed as Pe / τ.

  Returning to FIG. 4, the print control unit 21 </ b> A stores the number of light pulses per unit length (for example, 1 mm) of the scanning amount of the laser light by the scanning mechanism 14 as a fixed value. Then, the printing control unit 21A determines the repetition frequency f from the printing speed and the number of light pulses per unit length of the scanning amount of the laser beam.

  The average power of the optical pulse is a fixed value, for example. In this case, the excitation light source control unit 22 calculates the power of the laser light output from the semiconductor lasers 3, 9A to 9D based on the fixed value. And the excitation light source control part 22 controls the drivers 33 and 34A-34D so that the light of the calculated power is obtained from each of the semiconductor lasers 3, 9A-9D.

  However, the average power of the optical pulse may be set by a user, for example. In this case, data relating to the average power of the light pulse is added to the print setting information. For example, the excitation light source controller 22 receives this data via the print controller 21A and controls the drivers 33 and 34A to 34D as described above.

  Next, the print controller 21A determines whether or not a trigger signal has been input (step S3). If no trigger signal is input (NO in step S3), the process of step S3 is repeated. When a trigger signal is input to print control unit 21A (YES in step S3), print control unit 21A executes print processing (step S4).

  In step S <b> 4, the print control unit 21 </ b> A controls the pulse driving unit 30 to output a light pulse from the semiconductor laser 2. As a result, a high-power optical pulse enters the scanning mechanism 14. Further, the print control unit 21A controls the driver 35 so that the print data included in the print setting information is printed on the surface of the print object 50. When the driver 35 drives the scanning mechanism 14, print data is printed on the surface of the print object 50. When the process of step S4 ends, the entire process ends.

  As described above, the laser marking apparatus 100A according to the present embodiment can determine the light pulse conditions (pulse width and repetition frequency) based on the print setting information including the print speed. That is, the light pulse condition can be determined only by the user determining the printing speed. Therefore, according to the present embodiment, the burden on the user can be reduced, so that the utility value of the user can be increased.

FIG. 6 is a diagram showing the relationship between the pumping power and the average power of the optical pulse.
FIG. 7 is a diagram showing the relationship between the excitation power and the peak power of the optical pulse.

  In addition, excitation power is the sum total of the power of the laser beam output from the semiconductor lasers 3 and 9A-9D. 6 and 7, it can be seen that both the average power and the peak power increase as the excitation power increases.

  FIG. 8 is a diagram illustrating a result of irradiating the print target with the light pulse while changing the condition of the light pulse by the print control unit 21A. FIG. 8 shows the result of changing the repetition frequency and the pulse width while maintaining the peak power Pp of the optical pulse at approximately 3.0 (kW). For example, when the repetition frequency (f) is 100 (kHz), 200 (kHz), and 250 (kHz), according to the present embodiment, the pulse width is kept constant (approximately 10 (ns)) while It can be seen that the repetition frequency can be changed.

  For example, when the repetition frequencies are 400 (kHz), 450 (kHz), and 500 (kHz), the average power (Pd) is kept constant (approximately 7.3 (W)) in the present embodiment. However, it can be seen that the pulse width can be changed by changing the repetition frequency.

FIG. 9 is a diagram showing a result of printing on a printing object while changing the condition of the repetition frequency of the light pulse. With reference to FIG. 9, the printing result when the repetition frequency is changed between 100 to 500 kHz is shown. The conditions of average power, energy per pulse, and pulse width corresponding to each frequency correspond to the conditions shown in FIG. Further, the scanning speed of the light pulse by the scanning mechanism 14 was set to 5 m / s, and the material of the printing object was aluminum. The diameter of the light pulse (laser light spot) at this time was 43 μm (1 / e ² ).

  As shown in FIG. 9, the higher the repetition frequency, the closer the intervals between laser beam irradiation traces (hereinafter referred to as “marks”) formed on the surface of the printing object. When the Q switch element is used, the upper limit of the repetition frequency is about 200 (kHz), but in this embodiment, printing is performed at a repetition frequency higher than 200 (kHz) by pulse driving the semiconductor laser. Is possible.

  Thereby, even if the scanning speed of the scanning mechanism 14 is increased, the interval between the marks can be made dense, so that a figure can be drawn finely. In addition, the line of characters can be prevented from being interrupted. Furthermore, when the laser marking device of the present embodiment is installed on the production line, the printing time required per product can be shortened, so that productivity on the production line can be improved.

  FIG. 10 is a diagram illustrating the influence on the print quality with respect to the pulse width of the light pulse. Referring to FIG. 10, each of groups A, B, and C is a diagram showing a printing result when the repetition frequency and the energy per pulse are substantially the same and the pulse width is changed.

  For example, for group A, when the pulse width is 7.5 (ns), the peak power Pp is about 3.1 kW, whereas when the pulse width is 60 (ns), the peak power Pp is 0.4 ( kW). When the peak power is high, the surface of the printing object is shaved so as to show the irradiation mark of the light spot, whereas when the peak power is low, the mark of the light spot is hardly formed on the surface of the printing object.

  Groups B and C show the light pulse irradiation results when the energy per pulse is increased by increasing the average power as compared with group A. In the groups B and C, as in the case of the group A, the peak power decreases as the pulse width increases. Therefore, it is difficult to clearly form the irradiation spot of the light spot on the surface of the print target.

  Thus, according to the present embodiment, the degree of freedom in setting the repetition frequency can be increased. In particular, according to this embodiment, the repetition frequency of the optical pulse can be set higher than the upper limit of the repetition frequency of the Q switch.

  Further, according to the present embodiment, the energy per pulse is changed or the energy per pulse is kept constant while keeping the peak power of the light pulse constant by changing the pulse width of the light pulse. The peak power can be changed while holding. As a result, the size and the like of the mark formed on the surface of the print object can be changed variously. Thereby, various processing becomes possible.

  Furthermore, according to the present embodiment, by reducing the pulse width, it is possible to perform printing on the surface of the printing object even if the average power of the light pulse is small. By reducing the average power of the light pulse, the power consumption during the operation of the laser marking device can be reduced.

  Hereinafter, setting of the pulse width and repetition frequency of the optical pulse in the laser marking apparatus 100A of the present embodiment will be described with reference to the drawings.

[Embodiment 1]
In the first embodiment, the print control unit 21A stores the correlation between the repetition frequency f and the pulse width τ. The print controller 21A determines the repetition frequency and the pulse width based on the print setting information and this correlation.

  FIG. 11 is a diagram illustrating a correlation between the repetition frequency f and the pulse width τ stored in the print control unit 21A. Referring to FIG. 11, the relationship between repetition frequency f and pulse width τ is determined such that pulse width τ decreases as repetition frequency f increases while average power Pd is maintained at a constant value. This relationship is predetermined based on the result obtained by irradiating the print target with laser light while changing the repetition frequency f and / or the pulse width τ, for example.

  In the first embodiment, the print control unit 21A determines the repetition frequency f based on the print speed included in the print setting information. Furthermore, the print controller 21A determines the pulse width τ based on the repetition frequency f and the correlation shown in FIG. The processing performed by the print control unit 21A is the same as the processing of the flowchart shown in FIG.

  According to the first embodiment, when the user sets the printing speed, the light pulse condition is automatically determined. Thereby, since a user's burden can be reduced, according to Embodiment 1, the utility value for a user can be raised.

[Embodiment 2]
In the first embodiment, the repetition frequency f and the pulse width τ of the light pulse are constant regardless of the material of the printing object. However, for example, the reflectance of light is different between the case where the printing object is a metal and the case where the object is a resin. For this reason, it is preferable that the conditions of the light pulse need to be changed depending on whether the printing object is a metal or a resin.

  In the second embodiment, the printing conditions can be changed for each material of the printing object. As a result, the user can print on a printing object of various materials using one laser marking device.

  Referring to FIG. 1, laser marking device 100B of the second embodiment is different from laser marking device 100A in that laser marker control unit 20B is provided instead of laser marker control unit 20A. Referring to FIG. 2, laser marker control unit 20B is different from laser marker control unit 20A in that it includes a print control unit 21B instead of print control unit 21A. Since the configuration of other parts of laser marking apparatus 100B is the same as the configuration of the corresponding part of laser marking apparatus 100A, the following description will not be repeated.

  Similar to the print controller 21A, the print controller 21B stores in advance the correlation between the optical pulse repetition frequency f and the pulse width τ. FIG. 12 is a diagram showing the correlation between the repetition frequency f of the optical pulse and the pulse width τ stored in the print control unit 21B.

  Referring to FIG. 12, print control unit 21B stores a plurality of correlations between repetition frequency f and pulse width τ. These correlations are set for a material that is assumed in advance as the material of the printing object. In FIG. 12, a resin (shown as resin 1 in the figure) and two kinds of metals (shown as metal 1 and metal 2 in the figure) are shown as materials of the printing object.

  The type of resin and the type of metal are not particularly limited. Furthermore, the material of the printing object is not limited to resin and metal, and may include, for example, glass, paper, ceramic and the like.

  The material of the printing object is set by the user. In this case, as shown in FIG. 13, data relating to the material of the print target is added to the print setting information. Based on the print setting information, the print control unit 21B selects a correlation corresponding to the material indicated in the print setting information from a plurality of correlations (corresponding to the resin 1 in the case of the print setting information shown in FIG. 13). To determine the correlation). The subsequent processing of the print control unit 21B is the same as that in the first embodiment.

  As described above, according to the second embodiment, the user can set the repetition frequency and the pulse width of the light pulse by instructing the laser marking device about the material of the print target. As a result, the condition of the light pulse can be changed for each material of the printing object. Therefore, according to the second embodiment, it is possible to realize a laser marking device that increases the utility value of the user.

[Embodiment 3]
In the first embodiment, one combination of the optical pulse repetition frequency f and the pulse width τ is determined. However, this combination is predetermined by experiment or the like. Therefore, depending on the use conditions of the laser marking apparatus, it may be necessary to change one of the repetition frequency f and the pulse width τ.

  When the operation mode is the test mode, the laser marking device of the third embodiment is first determined from the correspondence between the optical pulse repetition frequency f and the pulse width τ, and the print setting information. And the initial value of the pulse width τ is determined. Next, the laser marking device performs a printing test while changing the repetition frequency f with the pulse width τ fixed at an initial value.

  Referring to FIG. 1, laser marking device 100C of the third embodiment is different from laser marking device 100A in that laser marker control unit 20C is provided instead of laser marker control unit 20A. Referring to FIG. 2, the laser marker control unit 20C is different from the laser marker control unit 20A in that a print control unit 21C is provided instead of the print control unit 21A. Since the structure of the other part of laser marking apparatus 100C is the same as the structure of the corresponding part of laser marking apparatus 100A, the following description will not be repeated.

  FIG. 14 is a diagram for explaining the setting of the repetition frequency f and the pulse width τ of an optical pulse performed by the print control unit 21C. Referring to FIG. 14, print control unit 21C first sets initial value f0 of repetition frequency f and initial value τ0 of pulse width τ in accordance with input print setting information and a previously stored correlation. This process is the same as the process in the first embodiment.

  The print controller 21C changes the repetition frequency f within a range from f1 to f2 while keeping the pulse width at τ0. This range includes the initial value f0.

  Specifically, the print control unit 21C changes the repetition frequency f between a plurality of values within a range from f1 to f2 and prints a test pattern. Therefore, a plurality of test patterns respectively corresponding to a plurality of repetition frequency values are printed on the surface of the printing object.

  The determination method of f1 and f2 is not specifically limited. For example, f1 and f2 may be values obtained by multiplying f0 by a predetermined ratio (for example, f1 = 0.9 × f0, f2 = 1.1 × f0), or a predetermined value is added to or subtracted from f0. (For example, f1 = f0−α, f2 = f0 + α). Further, the value of the repetition frequency f set by the print control unit 21C is not particularly limited.

  As shown in FIG. 9, when the scanning speed of the laser beam by the scanning mechanism 14 is the same, the interval between marks formed on the surface of the printing object can be changed by changing the repetition frequency f. According to the third embodiment, the user can find the optimum repetition frequency value from the result of the print test. Therefore, according to the third embodiment, it is possible to realize a laser marking device capable of improving the utility value of the user.

(Modification of Embodiment 3)
The operation of the laser marking apparatus described above is to change the repetition frequency f, but the pulse width τ may be changed.

  FIG. 15 is a diagram for explaining the setting of the repetition frequency f and the pulse width τ of an optical pulse performed by the print control unit 21C in the modification of the third embodiment. Referring to FIG. 15, print control unit 21C first sets initial value f0 of repetition frequency f and initial value τ0 of pulse width τ in accordance with input print setting information and a correlation stored in advance. Next, the print controller 21C changes the pulse width between a plurality of values in the range from τ1 to τ2 while printing the test pattern while keeping the repetition frequency f at f0. Note that the determination method of τ1, τ2 and the value of the pulse width τ set by the print control unit 21C are not particularly limited.

  According to this modification, the peak power of the optical pulse is changed by changing the pulse width while keeping the average power Pd and the repetition frequency f of the optical pulse constant. By changing the peak power of the light pulse, the size and depth of the mark formed on the print object can be changed. Therefore, the user can find the optimum pulse width value from the result of the print test.

[Embodiment 4]
The laser marking apparatus according to the fourth embodiment can increase the degree of freedom in setting the repetition frequency or pulse width as compared with the laser marking apparatus according to the third embodiment.

  Referring to FIG. 1, laser marking device 100D of the fourth embodiment is different from laser marking device 100A in that laser marker control unit 20D is provided instead of laser marker control unit 20A. Referring to FIG. 2, the laser marker control unit 20D is different from the laser marker control unit 20A in that a print control unit 21D is provided instead of the print control unit 21A. Since the configuration of other parts of laser marking apparatus 100D is the same as the corresponding part of laser marking apparatus 100A, the following description will not be repeated.

  FIG. 16 is a diagram illustrating a first example of the correspondence relationship between the repetition frequency of the optical pulse and the pulse width stored in the print control unit 21D. Referring to FIG. 16, in the first example, the correspondence between the repetition frequency and the pulse width of the optical pulse so that the pulse width τ is a constant value and the repetition frequency f is a value within the range of f1 to f2. A relationship is established. This correspondence is determined such that the range of the repetition frequency f is in the range of f1 to f2 for each of a plurality of pulse width values (τ1, τ2, etc.).

  For example, when the print setting information is given, the print control unit 21D sets the pulse width to τ1 and changes the repetition frequency between a plurality of values (fA, fB, fC) within the range of f1 to f2. Perform the test.

  The method by which the print control unit 21D determines the pulse width is not particularly limited. For example, the pulse width may be a fixed value. Further, as in the second embodiment, the user may set information on the material of the print target, and the information on the material of the print target may be included in the print setting information. In this case, the print control unit 21D determines the pulse width τ (τ1) for the print test from a plurality of pulse width values based on the information on the material of the print target included in the print setting information. .

  FIG. 17 is a diagram illustrating a second example of the correspondence relationship between the repetition frequency of the optical pulse and the pulse width stored in the print control unit 21D. Referring to FIGS. 17 and 16, in the second example, the repetition frequency and the pulse width of the optical pulse are such that the repetition frequency f is a constant value and the pulse width τ is a value within the range of τ1 to τ2. Correspondence relationship is established. This correspondence is determined such that the range of the pulse width is in the range of τ1 to τ2 for each of a plurality of repetition frequency values (f1, fA, fB, fC, f2).

  For example, when receiving the print setting information, the print control unit 21D sets the repetition frequency f to f1 based on the print speed included in the print setting information. Further, the print control unit 21D performs a print test by changing the pulse width τ between τA, τB, and τC based on the correspondence relationship between the repetition frequency and the pulse width shown in FIG.

  FIG. 18 is a diagram illustrating a third example of the correspondence relationship between the repetition frequency of the optical pulse and the pulse width stored in the print control unit 21D. Referring to FIG. 18, in the third example, a repetition frequency range and a pulse width range are predetermined. Specifically, the range of the repetition frequency f is a range from f1 to f2. The range of the pulse width τ is the range of τ1 to τ2. In FIG. 18, the region defined by the range of the repetition frequency and the range of the pulse width is indicated by hatching. The print controller 21D sets a plurality of sets of repetition frequency and pulse width from this area.

  Upon receiving the print setting information, the print controller 21D selects one set from a plurality of sets, determines the repetition frequency and pulse width of the light pulse output from the laser marking device, and performs a print test.

  FIG. 19 is a diagram illustrating an example of a set of repetition frequency and pulse width set by the print control unit 21D. Referring to FIG. 19, the set of repetition frequency and pulse width is set to (f1, τ1), (fa, τa), (fb, τb), for example. These sets are included in the range of the hatched area shown in FIG.

  The method for determining the combination of the repetition frequency and the pulse width is not particularly limited. For example, the print control unit 21D equally divides the hatched area in FIG. 18 into a plurality of areas (for example, four areas) and selects a combination of a repetition frequency and a pulse width corresponding to the center point of each area. Good.

  As described above, according to the fourth embodiment, one of the repetition frequency and the pulse width is changed without depending on the other in the predetermined repetition frequency range and the predetermined pulse width range. It becomes possible. As a result, the user can finely adjust the light pulse conditions so as to obtain a desired printing speed or desired printing quality while referring to the result of the printing test. Therefore, according to Embodiment 4, it is possible to realize a laser marking device capable of increasing the utility value of the user.

(Modification of Embodiment 4)
In the modification of the fourth embodiment, the user can set the repetition frequency and the pulse width. Referring to FIG. 1, in a modified example, the user inputs information on repetition frequency and pulse width to input unit 25. The input unit 25 outputs print setting information including information input by the user to the laser marker control unit 20D.

  FIG. 20 is a diagram illustrating an example of print setting information according to a modification of the fourth embodiment. As shown in FIG. 20, the print setting information includes repetition frequency information and pulse width information. The print controller 21D sets a repetition frequency and a pulse width based on the print setting information and performs a print test.

  According to this modification, the user can finely adjust the light pulse conditions so that a desired printing speed or desired printing quality can be obtained.

[Embodiment 5]
In the fifth embodiment, the laser marking apparatus prints a print pattern indicating the repetition frequency or pulse width condition of the light pulse on the surface of the print object.

  Referring to FIG. 1, laser marking device 100E according to the fifth embodiment is different from laser marking device 100A in that laser marker control unit 20E is provided instead of laser marker control unit 20A. Referring to FIG. 2, the laser marker control unit 20E is different from the laser marker control unit 20A in that a print control unit 21E is provided instead of the print control unit 21A. Since the structure of other parts of laser marking apparatus 100E is the same as the corresponding part of laser marking apparatus 100A, the following description will not be repeated.

  When the operation mode of the laser marking apparatus is the test mode, the print control unit 21E changes at least one of the repetition frequency and the pulse width of the light pulse between a plurality of values. The setting method of the repetition frequency and the pulse width by the print control unit 21E is the same as the method according to the third embodiment, for example. However, the setting method of the repetition frequency and the pulse width may be the same as the method according to the fourth or fifth embodiment. The print control unit 21E prints information for indicating a plurality of values.

  FIG. 21 is a diagram illustrating a printing pattern when the printing control unit 21E changes the repetition frequency of the light pulse. Referring to FIG. 21, print patterns PT <b> 1 to PT <b> 3 are printed on the surface of print object 50. The print control unit 21E performs printing in the order of the print patterns PT1, PT2, PT3 while increasing the repetition frequency. Therefore, the pitch of the marks formed on the surface of the print object 50 decreases in the order of the print patterns PT1, PT2, PT3. Print patterns PT1A and PT2A indicating that the repetition frequency is switched are printed between the print patterns PT1 and PT2 and between the print patterns PT2 and PT3, respectively.

  FIG. 22 is a diagram showing a print pattern when the print control unit 21E changes the pulse width of the light pulse. Referring to FIG. 22, print patterns PT <b> 3 to PT <b> 5 are printed on the surface of print object 50. The print control unit 21E performs printing in the order of the print patterns PT3, PT4, PT5 while shortening the pulse width. When the energy per pulse is the same, the peak power of the optical pulse increases as the pulse width decreases. Therefore, in the example shown in FIG. 22, the marks increase in the order of the print patterns PT3, PT4, and PT5. Print patterns PT3A and PT4A indicating that the pulse width has been switched are printed between the print patterns PT1 and PT2 and between the print patterns PT2 and PT3, respectively.

  For example, when the user uses the laser marking apparatus for the first time, the user can determine the light pulse conditions based on the print pattern shown in FIG. 21 or FIG. Thereby, a user's burden at the time of a user determining the conditions of an optical pulse can be eased. Therefore, according to the fifth embodiment, it is possible to realize a laser marking device capable of increasing the utility value of the user.

  In addition, the kind of information which shows the conditions of an optical pulse is not specifically limited. For example, the repetition frequency and / or pulse width values may be printed on the surface of the printing object. Further, the place where the information is printed is not particularly limited.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

It is a figure which shows the structure of the laser marking apparatus of this Embodiment. It is a functional block diagram of the laser marker control part 20A of FIG. It is a figure which shows an example of the print setting information input into 21 A of print control parts. It is a flowchart showing the process which the printing control part 21A performs. It is a figure for demonstrating the average power of an optical pulse, a pulse width, and a repetition frequency. It is a figure which shows the relationship between excitation power and the average power of an optical pulse. It is a figure which shows the relationship between excitation power and the peak power of an optical pulse. It is a figure which shows the result of having irradiated the printing target object with the light pulse, changing the conditions of a light pulse by 21 A of printing control parts. It is a figure which shows the result of having printed on the printing target object, changing the conditions of the repetition frequency of an optical pulse. It is a figure which shows the influence on the printing quality with respect to the pulse width of an optical pulse. It is a figure which shows the correlation with the repetition frequency f memorize | stored in the inside of the printing control part 21A, and pulse width (tau). It is a figure which shows the correlation with the repetition frequency f of the optical pulse and pulse width (tau) which the printing control part 21B memorize | stores. It is a figure which shows an example of the print setting information used for the laser marking apparatus of Embodiment 2. It is a figure for demonstrating the setting of the repetition frequency f of an optical pulse and pulse width (tau) which the printing control part 21C performs. FIG. 10 is a diagram for describing setting of a repetition frequency f and a pulse width τ of an optical pulse performed by a print control unit 21C in a modification of the third embodiment. It is a figure which shows the 1st example of the corresponding | compatible relationship between the repetition frequency of an optical pulse memorize | stored in printing control part 21D, and a pulse width. It is a figure which shows the 2nd example of the correspondence of the repetition frequency of an optical pulse memorize | stored in printing control part 21D, and a pulse width. It is a figure which shows the 3rd example of the correspondence of the repetition frequency of an optical pulse memorize | stored in printing control part 21D, and a pulse width. It is a figure which shows an example of the set of the repetition frequency and pulse width which printing control part 21D sets. FIG. 10 is a diagram illustrating an example of print setting information in a modification of the fourth embodiment. It is a figure which shows the printing pattern when the printing control part 21E changes the repetition frequency of a light pulse. It is a figure which shows the printing pattern when the printing control part 21E changes the pulse width of a light pulse.

Explanation of symbols

  1,8 optical fiber, 2,3,9A to 9D semiconductor laser, 4,6 isolator, 5,10 coupler, 7 band pass filter, 11 isolator, 12 end cap, 13 collimator lens, 14 scanning mechanism, 15 fθ lens , 20A to 20E Laser marker control unit, 21A to 21E Print control unit, 22 Excitation light source control unit, 23 Temperature control unit, 25 Input unit, 30 Pulse drive unit, 31 Pulse generator, 32, 33, 34A-34D, 35 Driver, 41 to 44, 45A to 45D Temperature controller, 50 printing object, 100A to 100E laser marking device, PT1 to PT5, PT1A to PT4A printing pattern.

Claims (14)

A semiconductor laser;
A drive unit for driving the semiconductor laser in pulses;
An optical amplification component that amplifies an optical pulse from the semiconductor laser in an excited state, receives the optical pulse on one end face, and an amplified light that is the optical pulse amplified by the optical amplification component in an excited state An optical fiber that outputs from the other end face;
An excitation light source that makes excitation light for making the light amplification component in an excitation state incident on the optical fiber;
A scanning mechanism for scanning the amplified light;
A control unit for controlling the repetition frequency and the pulse width of the amplified light by receiving the print setting information including the printing speed representing the scanning amount per unit time of the amplified light and controlling the driving device;
The said control part is a laser marking apparatus which memorize | stores previously the correspondence of the said repetition frequency and the said pulse width, and controls the said repetition frequency and the said pulse width based on the said print setting information and the said correspondence.   The said control part memorize | stores the correlation of the said repetition frequency and the said pulse width which were determined so that the said pulse width might become short as the said repetition frequency became high as the said correspondence. Laser marking device. The print setting information further includes information on the material of the print object,
The control unit stores the correspondence for each material of the print object, and determines the correspondence for controlling the repetition frequency and the pulse width based on the print setting information. Item 3. The laser marking device according to Item 2. The laser marking device has a test mode for performing a print test as an operation mode,
In the test mode, the control unit maintains the pulse width at a value determined based on the print setting information and the correspondence relationship, and determines the repetition frequency based on the pulse width and the correspondence relationship. The laser marking device according to claim 2, wherein the print test is performed by changing the value within a range including a value. The laser marking device has a test mode for performing a print test as an operation mode,
In the test mode, the control unit maintains the repetition frequency at a value determined based on the print setting information and the correspondence relationship, and the pulse width is a value determined by the repetition frequency and the correspondence relationship. The laser marking device according to claim 2, wherein the printing test is performed while changing the range within a range including   The laser marking device according to claim 2, wherein the correlation is a relationship between the repetition frequency and the pulse width when the average power of the pulsed light is constant. The laser marking device has a test mode for performing a print test as an operation mode,
The correspondence relationship is a relationship in which the pulse width is constant with respect to the repetition frequency,
The laser marking apparatus according to claim 1, wherein the control unit performs the printing test by changing the repetition frequency between a plurality of values according to the correspondence relationship in the test mode. The laser marking device has a test mode for performing a print test as an operation mode,
The correspondence relationship is a relationship in which the repetition frequency is constant with respect to the pulse width,
2. The laser marking device according to claim 1, wherein the control unit performs the print test by changing the pulse width between a plurality of values according to the correspondence relationship in the test mode. The laser marking device has a test mode for performing a print test as an operation mode,
The correspondence includes a plurality of combinations of the repetition frequency and the pulse width,
The laser marking apparatus according to claim 1, wherein the control unit selects a combination corresponding to the print setting information from the plurality of combinations in the test mode and performs the print test. The laser marking device is
An input unit for a user to input the print setting information;
10. The laser marking apparatus according to claim 7, wherein the print setting information further includes information input by the user for setting at least one of the repetition frequency and the pulse width. 10. The laser marking device has a test mode for performing a print test as an operation mode,
The laser marking device according to claim 1, wherein the control unit prints a test pattern in the test mode and changes the repetition frequency according to the correspondence relationship.   The laser marking device according to claim 11, wherein the control unit further prints information indicating the repetition frequency. The laser marking device has a test mode for performing a print test as an operation mode,
The laser marking device according to claim 1, wherein the control unit prints a test pattern in the test mode and changes the pulse width according to the correspondence relationship.   The laser marking device according to claim 13, wherein the control unit further prints information indicating the pulse width.