JP2018056261A - Laser beam emission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser beam emission device that is able to efficiently perform processing without degrading processing quality when a drive current caused to flow in an excitation semiconductor laser is changed with a change in the material of an object to be processed.SOLUTION: A storage section stores a correlation between the temperature of an excitation semiconductor laser and the current value of a drive current when the oscillation efficiency of a laser beam becomes maximum. A temperature control section performs a temperature determination process for determining, on the basis of the correlation stored in the storage part, the temperature of the excitation semiconductor laser corresponding to the current value of the drive current, set by a drive current value setting section, and a temperature control process for controlling the temperature of the excitation semiconductor laser such that it is equal to a temperature determined by the temperature determination process. Accordingly, degradation in processing quality is prevented, and the need to measure the temperature of the excitation semiconductor laser each time the current value of the drive current is changed is obviated.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a laser beam irradiation apparatus that processes an object by irradiating a laser beam.

2. Description of the Related Art Conventionally, as this type of laser light irradiation apparatus, an apparatus that performs processing such as printing by irradiating an object with laser light is known. This laser beam irradiation apparatus includes an excitation semiconductor laser, a laser medium that is excited by excitation light emitted from the excitation semiconductor laser, and oscillates laser light, and a galvanometer that deflects laser light emitted from the laser medium. A scanner. Then, by controlling the galvano scanner, the laser beam emitted from the laser medium is scanned on the object to perform printing.
By the way, in order to improve the processing quality, it is necessary to perform processing in a state where the oscillation efficiency of the laser light in the laser medium, that is, the output power of the laser light irradiated by the laser medium is maximized. The output power of the laser medium is proportional to the output power of the pumping light irradiated by the pumping semiconductor laser and varies depending on the oscillation wavelength of the pumping light irradiated by the pumping semiconductor laser. Therefore, in order to improve the processing quality, it is necessary to maximize the output power of the pumping semiconductor laser and make the oscillation wavelength of the pumping semiconductor laser substantially match the absorption spectrum of the laser medium.

However, the oscillation wavelength of the pumping semiconductor laser has temperature dependence. When the temperature of the pumping semiconductor laser changes, the oscillation wavelength of the pumping semiconductor laser changes and the output power of the laser medium changes.
For this reason, in order to improve the processing quality, it is necessary to control the temperature of the pumping semiconductor laser so that the output power of the laser medium is maximized.
Therefore, prior to processing, a technique has been proposed for obtaining the optimum temperature of the pumping semiconductor laser that maximizes the output power of the laser medium, and controlling the temperature of the pumping semiconductor laser so that the optimum temperature is obtained. (Patent Document 1).

JP 2002-158382 (paragraph 60, FIG. 3).

  Incidentally, the output power of the laser medium necessary for performing high-quality processing varies depending on the material forming the processing object. For example, a high output power is required for a processing object formed of a metal such as aluminum, and a low output power is required for a processing object formed of resin. Further, as shown in FIG. 8, the maximum output power of the laser medium is proportional to the current value (drive current value) of the drive current flowing in the pumping semiconductor laser.

FIG. 9 is a graph showing changes in the output power of the laser medium with respect to the temperature of the pumping semiconductor laser for each drive current value. As shown in this graph, the temperature (T1, T2, T3) of the pumping semiconductor laser when the output power of the laser medium becomes maximum is every driving current (I1, I2, I3) flowing through the pumping semiconductor laser. Different. Here, when the object is processed by supplying the driving current I1 to the pumping semiconductor laser, the temperature of the pumping semiconductor laser is controlled to T1 in order to maximize the output power of the laser medium. In addition, when the temperature of the pumping semiconductor laser is controlled to T1, the portion at the top of the curve in the graph indicated by the drive current I1 is used. In the vicinity of the top of the curve, the fluctuation of the output power of the laser medium with respect to the temperature change of the pumping semiconductor laser is small, and the degradation of the processing quality can be suppressed.
Next, if the material of the workpiece is changed and the driving current I2 is supplied to the pumping semiconductor laser, the temperature of the pumping semiconductor laser is controlled to the previous temperature T1. Even if the drive current I2 is supplied to the laser, the laser medium cannot output the maximum output power that can be output. In addition, since the portion where the slope of the curve is large is used in the graph indicated by the drive current I2, the fluctuation in the output power of the laser medium increases with a slight temperature change of the pumping semiconductor laser. Processing quality decreases. For example, a portion with a high processing density and a thin portion may occur, and stripes may be formed in the processing portion.

Therefore, in order to prevent the processing quality from deteriorating, the temperature of the pumping semiconductor laser capable of maximizing the output power of the laser medium is set for each drive current flowing through the pumping semiconductor laser, that is, a processing target is formed. It is conceivable to measure each material and control the pumping semiconductor laser so that the measured temperature is reached.
However, since the above-described conventional technique (Patent Document 1) is a technique for measuring the optimum temperature to be set for the excitation semiconductor laser before processing, every time the material of the processing object is changed, Since the optimum temperature must be measured before processing, there is a problem that processing efficiency is poor.
In other words, the conventional technique has a problem in that when the drive current passed through the pumping semiconductor laser is changed in accordance with the change of the material to be processed, the processing cannot be efficiently performed without reducing the processing quality. is there.

  Therefore, the present invention has been proposed to solve the above-described problem, and the processing quality is deteriorated when the driving current passed through the pumping semiconductor laser is changed in accordance with the change of the material of the processing object. It is an object of the present invention to provide a laser beam irradiation apparatus that can perform processing efficiently without doing so.

In order to achieve the above-described object, a laser beam irradiation apparatus of the invention according to this application is a laser beam irradiation apparatus that processes an object by irradiating a laser beam, and includes an excitation semiconductor laser, a drive current supply unit, The first feature is that the driving current value setting unit, the laser medium, the temperature control unit, and the storage unit are provided.
The excitation semiconductor laser emits excitation light having an intensity corresponding to the current value of the drive current flowing through the excitation laser, and the laser medium is excited by the excitation light and oscillates the laser light. The drive current value setting unit sets the current value of the drive current, and the drive current supply unit supplies the drive current to the excitation semiconductor laser. The storage unit stores a correspondence relationship between the temperature of the pumping semiconductor laser and the current value of the drive current when the laser light oscillation efficiency is maximized. The temperature control unit controls the temperature of the pumping semiconductor laser to a predetermined temperature. Further, the temperature control unit is configured to determine a temperature of the excitation semiconductor laser corresponding to the current value of the drive current set by the drive current value setting unit based on the correspondence relationship stored in the storage unit; And a temperature control process for controlling the temperature of the pumping semiconductor laser so as to be the temperature determined by the temperature determination process.

As described above, the temperature control unit determines the temperature of the excitation semiconductor laser corresponding to the current value of the drive current set by the drive current value setting unit based on the correspondence stored in the storage unit, The temperature of the pumping semiconductor laser can be controlled so as to be the determined temperature.
Therefore, when the laser beam irradiation apparatus having the first feature is implemented, the laser beam oscillation is performed only by setting the current value of the drive current and flowing the drive current of the drive current value through the pumping semiconductor laser. Since the temperature of the pumping semiconductor laser when the efficiency is maximized is automatically determined, and the temperature of the pumping semiconductor laser can be automatically controlled so as to be the temperature, the processing quality does not deteriorate.
In addition, since the correspondence relationship between the temperature of the pumping semiconductor laser when the laser beam oscillation efficiency is maximized and the current value of the drive current is stored in advance in the storage unit, the laser beam oscillation efficiency is maximized. It is not necessary to measure the temperature of the pumping semiconductor laser every time the current value of the drive current is changed.

  The second feature of the laser light irradiation apparatus of the invention according to this application is that the correspondence stored in the storage unit has a characteristic indicating a change in the oscillation efficiency of the laser light with respect to a temperature change of the pumping semiconductor laser. Based on the measurement results measured for each current value of the drive current, and based on the measurement results, the temperature of the pumping semiconductor laser when the oscillation efficiency is maximized is determined for each current value of the drive current. It is that it is obtained by associating with.

That is, the correspondence stored in the storage unit is based on the measurement result actually measured.
Therefore, if the laser beam irradiation apparatus having the second feature is implemented, the excitation semiconductor laser can be controlled to a temperature based on the actually measured measurement result, so that the oscillation efficiency can be maximized accurately. Therefore, processing quality can be improved.

  The third feature of the laser light irradiation apparatus of the invention according to this application is that the correspondence relationship stored in the storage unit is determined by a linear function having the current value of the drive current as a variable, and the temperature In the determination process, the temperature of the pumping semiconductor laser corresponding to the current value of the drive current set by the drive current value setting unit is determined by calculation using the linear function.

That is, the temperature of the excitation semiconductor laser corresponding to the current value of the drive current set by the drive current value setting unit is determined by calculation using a linear function.
Therefore, if the laser beam irradiation apparatus having the third feature is implemented, the storage capacity required for the storage unit can be reduced as compared with the configuration in which the correspondence relationship is stored in the storage unit in the data table format.

  The fourth feature of the laser light irradiation apparatus of the invention according to this application is that the temperature range of the excitation semiconductor laser defined in the correspondence relationship stored in the storage unit is processed by the laser light. The temperature is within the temperature range of the semiconductor laser for excitation when performing.

That is, there is no possibility of processing the object at a temperature other than the temperature at which the object is processed.
Therefore, if the laser beam irradiation apparatus having the fourth feature is implemented, there is no possibility that the processing quality is lowered by a certain level or more.

  Further, a fifth feature of the laser light irradiation apparatus of the invention according to this application is provided with a display unit on which a type of an object to be processed can be selected, and the drive current value setting unit includes an object. And the current value of the drive current suitable for processing are associated with each object type, and the temperature determination process is performed by the drive associated with the object type selected on the display unit. The current value of the current is selected from the drive current value setting unit, and the temperature of the pumping semiconductor laser corresponding to the selected current value of the drive current is determined based on the correspondence relationship.

In other words, simply by performing a simple operation of selecting the type of object on the display unit, the current value of the drive current necessary for processing the selected object is automatically selected, and the selected drive current is selected. The temperature of the pumping semiconductor laser corresponding to the current value is automatically determined based on the correspondence stored in the storage unit.
Therefore, if the laser beam irradiation apparatus having the fifth feature is implemented, the current value of the drive current and the temperature of the pumping semiconductor laser necessary for processing the object with high quality can be easily set. Therefore, preparation time before processing can be shortened, so that processing efficiency can be increased.

  Further, a sixth feature of the laser light irradiation apparatus of the invention according to this application is that the temperature determination process changes the current value of the drive current set by the drive current value setting unit according to the change over time of the laser medium, The temperature of the pumping semiconductor laser corresponding to the changed current value of the drive current is determined based on the correspondence stored in the storage unit.

That is, even when the laser medium changes over time and the output power decreases, the laser medium is irradiated from the pumping semiconductor laser by changing the current value of the drive current supplied to the pumping semiconductor laser. Since the intensity of the excitation light is changed, the oscillation efficiency of the laser light in the laser medium is automatically changed, so that it is possible to prevent the output power from being lowered as the laser medium changes with time.
Furthermore, even when the current value set in the drive current value setting unit is changed as described above, the temperature of the excitation semiconductor laser corresponding to the changed current value is stored in the storage unit. Since it determines based on a relationship, the oscillation efficiency of a laser beam can be improved.
Therefore, if the laser beam irradiation apparatus having the sixth feature is implemented, the processing quality of the object can be stabilized even when the laser medium changes with time.

  A seventh feature of the laser light irradiation apparatus of the invention according to this application is that the temperature control unit includes a Peltier element for controlling the temperature of the excitation semiconductor laser.

That is, since the Peltier element does not have a movable part, there is no possibility that the excitation semiconductor laser is adversely affected by vibration transmission. Moreover, since the Peltier element has good temperature responsiveness and can be heated and cooled, the temperature of the pumping semiconductor laser can be controlled with high accuracy.
Therefore, if the laser beam irradiation apparatus having the seventh feature is implemented, the processing quality of the object can be stabilized.

  By implementing the laser light irradiation apparatus of the invention according to this application, when changing the drive current that flows to the pumping semiconductor laser in accordance with the change of the material of the object to be processed, the processing can be efficiently performed without reducing the processing quality. It can be carried out.

It is explanatory drawing which shows schematic structure of the laser beam irradiation apparatus of 1st Embodiment. It is a block diagram which shows the electrical structure of the laser beam irradiation apparatus shown in FIG. It is a graph of a linear function which shows the correspondence of the drive current value of the semiconductor laser for excitation, and the preset temperature of the semiconductor laser for excitation. (A) is explanatory drawing which shows the structure of a drive current value determination table, (b) is explanatory drawing which shows the calculation result of optimal temperature. It is explanatory drawing which shows a printing target material selection screen. It is a flowchart which shows the flow of the temperature control which CPU performs. It is a flowchart which shows the flow of the temperature control which CPU performs in 2nd Embodiment. It is a graph which shows the relationship between the electric current value of the drive current which flows into the semiconductor laser for excitation, and the maximum output power of a laser medium. It is a graph which shows the relationship between the temperature of the semiconductor laser for excitation, and the output power of a laser medium for every drive current.

<First Embodiment>
[Schematic Configuration of Laser Light Irradiation Apparatus 1]
A schematic configuration of a laser beam irradiation apparatus 1 according to the first embodiment of the present invention will be described with reference to FIG.
The laser light irradiation device 1 includes a laser light irradiation device main body 2, a laser controller 3, and a power supply unit 5. The laser beam irradiation device main body 2 prints characters, symbols, figures, etc. by two-dimensionally scanning the laser beam L on the printing surface 6A of the printing object 6.

  The laser controller 3 is electrically connected to a personal computer (hereinafter referred to as “PC”) 7 so as to be capable of bidirectional communication, and is electrically connected to the laser light irradiation apparatus main body 2 and the power supply 5. . The laser controller 3 controls the laser light irradiation apparatus main body 2 and the power supply unit 5 based on printing information such as characters, symbols, and graphics transmitted from the PC 7, control parameters, and various instruction information. That is, the laser controller 3 controls the entire laser light irradiation apparatus 1.

[Schematic Configuration of Laser Light Irradiation Device Main Body 2]
A schematic configuration of the laser light irradiation apparatus main body 2 will be described with reference to FIG. In the description of the laser light irradiation apparatus main body 2, the direction in which the laser light L is irradiated from the printing laser oscillator 11 toward the galvano scanner 18 is the front direction of the laser light irradiation apparatus main body 2, and the opposite direction. Is the rear direction, and the front-rear direction is the X direction. Further, the vertical direction to the mounting surface of the main body base 12 to which the printing laser oscillator 11 is mounted is the vertical direction of the laser light irradiation apparatus main body 2. And the direction orthogonal to the up-down direction and the front-back direction of the laser light irradiation apparatus main body 2 is the left-right direction of the laser light irradiation apparatus main body 2 and is defined as the Y direction.

As shown in FIG. 1, the laser beam irradiation apparatus main body 2 includes a main body base 12, a laser oscillation unit 13 that irradiates a laser beam L, a galvano scanner 18, an fθ lens 19, and the like. Covered with a case cover.
The laser oscillation unit 13 includes a printing laser oscillator 11 and the like. The galvano scanner 18 is attached to the upper side of a through hole (not shown) formed in the vertical direction at the front end of the main body base 12, and the laser light L emitted from the laser oscillation unit 13 is passed through the through hole. Through which two-dimensional scanning is performed. The galvano scanner 18 includes a galvano X-axis motor 22, a galvano Y-axis motor 23, and a main body 25. A scanning mirror (not shown) is rotatably attached to the tip of each motor shaft. ing. Each scanning mirror is arranged so that each reflecting surface faces each other. The laser light L is two-dimensionally scanned downward by controlling the rotations of the motors 22 and 23 to rotate the scanning mirrors. The two-dimensional scanning direction is a front-rear direction (X direction) and a left-right direction (Y direction).

  The fθ lens 19 condenses the laser light L two-dimensionally scanned by the galvano scanner 18 on the print surface 6A of the print object 6 disposed below. In other words, by controlling the rotation of the motors 22 and 23, the laser light L is generated in the front-rear direction (X direction) and the left-right direction (Y direction) in a desired print pattern on the print surface 6A of the print object 6. Two-dimensional scanning is performed.

[Schematic configuration of power supply unit 5]
Next, a schematic configuration of the power supply unit 5 will be described with reference to FIG. The power supply unit 5 includes a casing 27, and inside the casing 27, an excitation semiconductor laser 28, a laser driver 29, a power supply 31, and a temperature detection control unit 34 a are arranged. The pumping semiconductor laser 28 irradiates pumping light having an intensity corresponding to the current value of the driving current flowing through the pumping semiconductor laser 28. The power supply 31 supplies drive current to the pumping semiconductor laser 28 via the laser driver 29. The laser driver 29 DC drives the pumping semiconductor laser 28 based on the drive information input from the laser controller 3. The temperature detection control unit 34a performs temperature detection and temperature control of the excitation semiconductor laser 28, as will be described later.

  The printing laser oscillator 11 is optically connected to the pumping semiconductor laser 28 by an optical fiber 33. The pumping semiconductor laser 28 irradiates the optical fiber 33 with pumping light with respect to the pulsed drive current input from the laser driver 29. That is, excitation light from the excitation semiconductor laser 28 is incident on the printing laser oscillator 11 via the optical fiber 33. The pumping semiconductor laser 28 is configured using, for example, GaAs.

  The printing laser oscillator 11 has a YAG laser 35 (see FIG. 2) as a laser medium. The YAG laser 35 is excited by excitation light incident from the excitation semiconductor laser 28 via the optical fiber 33 and oscillates a pulse laser that is laser light for printing. The YAG laser 35 is provided with a temperature detection control unit 34b (see FIG. 2). The temperature detection control unit 34b performs temperature detection and temperature control of the YAG laser 35.

[Electric Configuration of Laser Irradiation Apparatus 1]
Next, the electrical configuration of the laser beam irradiation apparatus 1 will be described with reference to FIG.
A PC 7, a galvano controller 45, a laser driver 29, a Peltier driver 48, an A / D converter 47 and the like are electrically connected to the laser controller 3.

  The laser controller 3 is electrically connected to the PC 7 so as to be capable of bidirectional communication, and is configured to be able to receive print information transmitted from the PC 7, various instruction information from the user, and the like. In addition, an input operation unit 71 including a mouse 73 and a keyboard 74 (FIG. 1) and an LCD (liquid crystal display) 72 are electrically connected to the PC 7 via an input / output interface (not shown). ing. The LCD 72 displays a print target material selection screen 72a (FIG. 5) used when selecting a print target material, various instruction information of the user, temperature information output from the laser controller 3, and the like.

  The laser controller 3 includes a CPU 51, a RAM 52, a ROM 53, a timer 54, and the like. The CPU 51, RAM 52, ROM 53, and timer 54 are electrically connected by a bus line (not shown), and exchange of data is performed between them. The CPU 51 controls various units such as the galvano controller 45, the laser driver 29, and the Peltier driver 48 of the laser light irradiation apparatus 1 that are electrically connected by executing various programs stored in the ROM 53. The RAM 52 is used as a main storage device for the CPU 51 to execute various processes. The timer 54 measures the driving time of the YAG laser 35, the time required when the CPU 51 executes various processes, and the like.

  The CPU 51 outputs XY coordinate data, galvano scanning speed information, and the like of the print pattern calculated based on the print information input from the PC 7 to the galvano controller 45. Further, the CPU 51 outputs to the laser driver 29 the drive pattern of the pumping semiconductor laser 28 such as the pumping light output of the pumping semiconductor laser 28 and the pumping light output period set based on the print information input from the PC 7. Further, the CPU 51 determines a process for determining the current value of the drive current that the laser driver 29 supplies to the pumping semiconductor laser 28, a process for setting a temperature corresponding to the determined current value, and the set temperature. The process which controls the Peltier device 38 is performed so that it may become. These processes will be described later.

  The galvano controller 45 calculates each drive angle, each rotation speed, and the like of the galvano X-axis motor 22 and the galvano Y-axis motor 23 based on the XY coordinate data of the print pattern input from the laser controller 3, galvano scanning speed information, and the like. Then, motor drive information representing the calculated drive angles and rotation speeds is output to the galvano driver 46. The galvano driver 46 drives the galvano X-axis motor 22 and the galvano Y-axis motor 23 based on the motor drive information input from the galvano controller 45 to scan the laser beam L two-dimensionally.

  The laser driver 29 drives the pumping semiconductor laser 28 based on laser drive information such as the output intensity of the pumping light of the pumping semiconductor laser 28 input from the laser controller 3 and the output period of the pumping light. The excitation light emitted from the excitation semiconductor laser 28 drives the YAG laser 35.

  For example, the input operation unit 71 is operated by the user of the laser beam irradiation apparatus 1 and a print command including print information is input to the PC 7. Then, the CPU 51 receives a print command from the PC 7 and outputs XY coordinate data of the print pattern, galvano scanning speed information, and the like to the galvano controller 45. Further, the CPU 51 outputs a drive pattern to the laser driver 29. Then, the galvano driver 46 and the laser driver 29 are driven. Further, the YAG laser 35 is driven by the excitation light irradiated by the excitation semiconductor laser 28. Then, the laser beam L emitted from the YAG laser 35 is two-dimensionally scanned on the printing surface 6A of the printing object 6, and the printing object is printed.

  The temperature detection control unit 34 a includes a temperature sensor 36 and a Peltier element 38. The temperature of the pumping semiconductor laser 28 is measured by the temperature sensor 36. Then, the excitation semiconductor laser 28 is heated and cooled by the Peltier element 38. The temperature detection control unit 34 b includes a temperature sensor 37 and a Peltier element 39. A temperature sensor 37 measures the temperature of the YAG laser 35. Then, the YAG laser 35 is heated and cooled by the Peltier element 39. The CPU 51 acquires temperature information measured by the temperature sensors 36 and 37 via the A / D converter 47. Then, the set temperature (target temperature) and the detected temperature are compared to calculate Peltier drive information. Here, the Peltier drive information is information for determining the polarity and voltage value of the voltage applied to each of the Peltier elements 38 and 39. Then, the CPU 51 transmits the calculated Peltier drive information to the Peltier driver 48. The Peltier driver 48 drives the Peltier elements 38 and 39 based on the received Peltier drive information. That is, the CPU 51 controls the temperatures of the excitation semiconductor laser 28 and the YAG laser 35 using the temperature sensors 36 and 37 and the Peltier elements 38 and 39. As a result, the oscillation wavelengths of the pumping semiconductor laser 28 and the YAG laser 35 are adjusted, and both the lasers 28 and 35 can output the maximum output power. The set temperature of the pumping semiconductor laser 28 is about 48 to 52 ° C., and the set temperature of the YAG laser 35 is about 25 ° C.

[Experiment]
Next, an experiment conducted by the inventor of this application will be described with reference to FIGS.
The inventor of this application shows the correspondence relationship between the drive current value of the pumping semiconductor laser 28 that can maximize the oscillation efficiency of the YAG laser 35, that is, the output power, and the temperature of the pumping semiconductor laser 28. The required experiment was conducted. FIG. 3 is a graph of a linear function showing the correspondence between the drive current value of the pumping semiconductor laser and the set temperature of the pumping semiconductor laser. FIG. 4A is an explanatory diagram showing the configuration of the drive current value determination table 52a, and FIG. 4B is an explanatory diagram showing the calculation result of the optimum temperature.

  This experiment was performed on a total of three types of printing objects, that is, two types of printing objects formed of resins having different printing surfaces and a printing object having a printing surface formed of non-ferrous metal. Further, the laser output power required for printing with high quality differs depending on the printing object. For two types of printing objects whose printing surfaces are formed of resin, the excitation semiconductor laser 28 has laser number 1. Two different conditions were used.

  The average output power of the YAG laser 35 when the pumping semiconductor laser 28 is used under the condition of laser number 1 is 1.50 W (FIG. 4), and the pumping semiconductor laser 28 necessary for obtaining the average output power. Was about 3.8 A (measurement point C1 in FIG. 3), and the set temperature of the pumping semiconductor laser 28 at that time was 51.11 ° C. (measurement point C1 in FIG. 3). The average output power of the YAG laser 35 when the pumping semiconductor laser 28 is used under the condition of the laser number 2 is 2.25 W (FIG. 4), and the pumping semiconductor necessary for obtaining the average output power. The drive current value of the laser 28 is about 4.2 A (measurement point C2 in FIG. 3), and the set temperature of the excitation semiconductor laser 28 at that time was 50.78 ° C. (measurement point C2 in FIG. 3). . Further, the average output power of the YAG laser 35 when the pumping semiconductor laser 28 is used with respect to a printing object whose printing surface is formed of a non-ferrous metal is 5.00 W (FIG. 4). The drive current value of the pumping semiconductor laser 28 necessary for obtaining the above is about 5.66 A (measurement point C3 in FIG. 3), and the set temperature of the pumping semiconductor laser 28 at that time is 48.9 ° C. (Measurement point C3 in FIG. 3). Each of the above average output powers is an average of the maximum output power.

  Then, the inventor plotted the measurement points C1 to C3 corresponding to the drive current value of the excitation semiconductor laser 28 and the measured value of the set temperature on the graph based on the above three measurement results (FIG. 3). Next, the inventor determines, based on these three measured values, the optimum temperature of the pumping semiconductor laser 28 when the oscillation efficiency of the laser beam is maximized and the drive current value of the pumping semiconductor laser 28 at that time. An approximate expression showing the correspondence was derived. The approximate expression is an approximate expression of a linear function that can obtain the optimum temperature using the drive current as a variable. The linear function is shown in the following formula 1. In this experiment, Equation 1 was derived using the method of least squares. In Equation 1, x is a drive current value of the pumping semiconductor laser 28, and y is an optimum temperature to be set in the pumping semiconductor laser 28.

  y = −1.2119x + 55.777 (Equation 1)

  As shown in FIG. 3, the three measurement points C <b> 1 to C <b> 3 exist on or near the straight line of the linear function expressed by the above-described Expression 1. That is, the optimum temperature y calculated based on the above equation 1 is a value that is the same as or very close to the actually measured value. Therefore, even if the material to be printed is changed and the required drive current value of the pumping semiconductor laser 28 is changed, the required drive current value is calculated by substituting the drive current value into x in the above equation 1. The optimum temperature y of the pumping semiconductor laser 28 could be calculated.

FIG. 4B shows the result of calculating the optimum temperature y by substituting the three drive current values used in the above-described experiment into x in the above equation 1. While the set temperature measured at the drive current value of 3.80 A in the experiment was 51.11 ° C., the optimum temperature calculated based on Equation 1 was 51.2 ° C., and the calculated value was the measured value. The error is + 0.09 ° C. In addition, while the set temperature measured at the drive current value of 4.20 A in the experiment was 50.78 ° C., the optimum temperature calculated based on Equation 1 was 50.70 ° C., and the calculated value was The error is −0.08 ° C. with respect to the measured value. In addition, the set temperature measured at the drive current value of 5.66 A in the experiment was 48.9 ° C., whereas the optimum temperature calculated based on Equation 1 was 48.9 ° C., and the calculated value was The error is 0.0 ° C. with respect to the measured value.
That is, the optimum temperature calculated by Equation 1 is less than ± 0.1 ° C. with respect to the actually measured set temperature, and the optimum temperature is calculated by substituting the drive current value for x in Equation 1. The set optimum temperature can be set as the target temperature.

The above equation 1 is stored in the ROM 53 (FIG. 2), and the CPU 51 calculates the optimum temperature y based on the equation 1 stored in the ROM 53 when controlling the temperature of the excitation semiconductor laser.
Further, the set temperature of the excitation semiconductor laser 28 is about 48 to 52 ° C., and is within the set temperature range of the excitation semiconductor laser 28 when printing an object with laser light. In this case, the object is not printed, so that there is no possibility that the print quality is deteriorated by a certain level or more.

[Driving current value determination table]
Next, the drive current value determination table will be described with reference to FIG. FIG. 4A is an explanatory diagram showing the configuration of the drive current value determination table.

  The drive current value determination table 52a is used when selecting the drive current value of the pumping semiconductor laser 28 necessary for the YAG laser 35 to output the maximum output power. The drive current value determination table 52a is rewritably stored in the RAM 52 (FIG. 2), and the CPU 51 reads the necessary data with reference to the drive current value determination table 52a when necessary. In the drive current value determination table 52a, a printing target material, a laser number, an average output power, and a drive current value are associated with each other. That is, in the drive current value determination table 52a, the type of material to be printed and the drive current value suitable for printing are associated with each type of material to be printed.

  Three types of printing target materials, resin, non-ferrous metal, and metal, are set as the printing target material. Laser numbers 1 to 3 are set for the resin, and laser numbers are not set for non-ferrous metals and metals. The average output power of the YAG laser 35 of 1.50 to 5.00 W is set for laser numbers 1 to 3, non-ferrous metals and metals. Further, the drive current values 3.80 to 5.66 A of the excitation semiconductor laser 28 are associated with the laser numbers 1 to 3 and the non-ferrous metal and the metal, respectively.

[Printable material selection screen]
Next, a print target material selection screen displayed on the LCD 72 will be described with reference to FIG. FIG. 5 is an explanatory diagram showing a print target material selection screen.

As shown in FIG. 5, a print target material selection screen 72a is displayed on the screen of the LCD 72 (FIG. 1). The print target material selection screen 72a displays buttons A1 to A3 for selecting a print target material and buttons B1 to B3 for selecting laser numbers 1 to 3. The button A1 is a button for selecting a resin, the button A2 is a button for selecting a non-ferrous metal, and the button A3 is a button for selecting a metal. Buttons B1 to B3 are buttons for selecting laser numbers 1 to 3. By operating the mouse 73 (FIG. 1) to move the cursor onto a desired button and clicking a switch (not shown) of the mouse 73, an item displayed on the button is selected. Further, when a touch panel is formed on the surface of the LCD 72, an item displayed on the button can be selected by touching a desired button with a finger or a touch pen.
The user selects a material to be printed and a laser number using a print material selection screen 72a displayed on the LCD 72 before printing on the object.

[Temperature control processing]
Next, a temperature control process executed by the CPU 51 (FIG. 2) in order to control the temperature of the pumping semiconductor laser 28 to the set temperature will be described based on the flowchart of FIG.

  The CPU 51 determines whether or not the user has selected any of the buttons A1 to A3 on the print target material selection screen 72a (FIG. 5) displayed on the LCD 72, that is, whether or not the print target material has been received. (Step (hereinafter abbreviated as S) 6). If the CPU 51 determines that the print target material has been received (S6: Yes), the CPU 51 determines the print target material corresponding to the button selected by the user (S7). Subsequently, the CPU 51 determines whether or not the printing target material determined in S7 is resin (S8). If it is determined that the material is resin (S8: Yes), the user selects one of the buttons B1 to B3. It is determined whether or not a laser number has been received (S9). If the CPU 51 determines that the laser number has been received (S9: Yes), the CPU 51 determines the drive current value corresponding to the received laser number with reference to the drive current value determination table 52a (FIG. 4A). (S10). For example, when the received laser number is 1, the drive current value is determined to be 3.80 A associated with laser number 1 in the drive current value determination table 52a. If it is determined in S8 that the resin is not resin (S8: No), the driving current value is determined to be 5.66 A associated with the non-ferrous metal and the metal in the driving current value determination table 52a (S10).

Subsequently, the CPU 51 calculates the optimum temperature y to be set to the set temperature y1 by substituting the drive current value determined in S10 for x in the equation 1 stored in the ROM 53 (S11). For example, when the drive current value determined in S10 is 3.80 A, the optimum temperature y = 51.2 ° C. is calculated by substituting 3.80 for x in Equation 1.
That is, the CPU 51 selects from the drive current value determination table 52a (FIG. 4A) the drive current value associated with the type of print target material selected on the print target material selection screen 72a (FIG. 5). Then, the optimum temperature y of the pumping semiconductor laser corresponding to the selected drive current value is determined based on Equation 1.

Subsequently, the CPU 51 sets the optimum temperature y calculated in S11 to the set temperature (target temperature) y1 (S12), controls the Peltier driver 48 (FIG. 2), and controls the Peltier element 38 to the set temperature y1 ( S13). That is, the pumping semiconductor laser 28 is controlled to the set temperature y1. Subsequently, the CPU 51 determines whether or not the temperature of the Peltier element 38, that is, the temperature of the pumping semiconductor laser 28 has reached the set temperature y1 based on the temperature data taken from the temperature sensor 36 via the A / D converter 47. (S14: No), the temperature control of the Peltier element 38 is continued (S13).
That is, the CPU 51 controls the temperature of the pumping semiconductor laser 28 so as to be the set temperature y1 set in S12.

When the CPU 51 determines that the temperature of the Peltier element 38, that is, the temperature of the pumping semiconductor laser 28 has reached the set temperature y1 (S14: Yes), the temperature control process ends.
As described above, the user can control the excitation semiconductor laser 28 to the set temperature only by selecting the print target material and the laser number using the print target material selection screen 72a.

[Effect of the first embodiment]
(1) If the laser beam irradiation apparatus 1 of the first embodiment described above is implemented, it is only necessary to set the drive current value, and when the drive current of that drive current value is passed through the excitation semiconductor laser 28, the laser beam irradiation The temperature of the pumping semiconductor laser 28 when the oscillation efficiency is maximized is automatically determined, and the temperature of the pumping semiconductor laser 28 can be automatically controlled to reach that temperature, so that the print quality is deteriorated. do not do.
In addition, since the correspondence relationship between the temperature of the pumping semiconductor laser 28 when the laser beam oscillation efficiency is maximized and the drive current value is stored in the ROM 53 in advance, the laser beam oscillation efficiency is maximized. It is not necessary to measure the temperature of the pumping semiconductor laser 28 every time the drive current value is changed.

(2) If the laser beam irradiation apparatus 1 is implemented, the correspondence stored in the ROM 53 is based on the actually measured measurement result, so that the excitation semiconductor laser 28 is actually measured. Since the oscillation efficiency can be maximized accurately, the print quality can be improved.

(3) Further, when the laser beam irradiation apparatus 1 is implemented, the temperature of the pumping semiconductor laser 28 corresponding to the drive current value set in the drive current value determination table 52a is expressed by using a linear function equation 1. Since it can be determined by calculation, the storage capacity required for the ROM 53 can be reduced as compared with the configuration in which the above correspondence is stored in the ROM 53 in the data table format.

(4) Further, if the laser beam irradiation apparatus 1 is implemented, the set temperature range of the excitation semiconductor laser 28 calculated by the linear function Equation 1 is used for excitation when printing an object with laser light. Since the temperature is within the set temperature range of the semiconductor laser 28, there is no possibility that the object is printed at a set temperature other than the set temperature when printing the object, and therefore there is no possibility that the print quality will be lowered by a certain level or more.

(5) Furthermore, if the laser beam irradiation apparatus 1 is implemented, the selected print target material and laser number can be obtained simply by performing a simple operation of selecting the print target material and laser number on the print target material selection screen 72a. The current value of the driving current necessary for the current is automatically selected, and the temperature of the pumping semiconductor laser 28 corresponding to the selected current value of the driving current is automatically calculated by the calculation using the expression 1 of the linear function. It is determined.
Therefore, if the laser beam irradiation apparatus 1 is implemented, the current value of the drive current and the temperature of the excitation semiconductor laser 28 necessary for printing the object with high quality can be easily set. Since the preparation time can be shortened, the printing efficiency can be increased.

(6) Furthermore, if the laser beam irradiation apparatus 1 is implemented, the temperature of the pumping semiconductor laser 28 is controlled by the Peltier element 38 having no moving part, and therefore the pumping semiconductor laser 28 may be adversely affected by vibration transmission. There is no.
In addition, since the Peltier element 38 has good temperature responsiveness and can be heated and cooled, the temperature of the excitation semiconductor laser 28 can be controlled with high accuracy, so that the print quality of the object can be stabilized. .

(7) In other words, if the laser beam irradiation device 1 is implemented, when the drive current passed through the pumping semiconductor laser 28 is changed in accordance with the change in the material of the print target, the print can be efficiently performed without deteriorating the print quality. It can be performed.

Second Embodiment
Next, a second embodiment of the present invention will be described with reference to FIG.
FIG. 7 is a flowchart in which a part of the flow of the temperature control process executed by the CPU 51 is omitted. In addition, about the same structure as the laser beam irradiation apparatus 1 of 1st Embodiment, the same code | symbol is used.

  The output power of the YAG laser 35 decreases as the usage time elapses. Therefore, the laser beam irradiation apparatus 1 of this embodiment increases the drive current value of the pumping semiconductor laser 28 in order to increase the intensity of the pumping light irradiated by the pumping semiconductor laser 28 and increases the output power of the YAG laser 35. It is characterized by increasing the output power (increasing oscillation efficiency) to compensate for the decrease in output power. The driving time of the YAG laser 35 is measured by the timer 54 (FIG. 2). Also, the drive current value newly set in the drive current value determination table 52a is obtained in advance by experiments.

When the CPU 51 determines that the laser beam irradiation device 1 has started (S1: Yes in FIG. 7), it determines whether or not the driving time of the YAG laser 35 measured by the timer 54 exceeds 100% of the rated life. (S2). Here, if it is determined that it has exceeded (S2: Yes), it is notified that the YAG laser 35 is in the replacement period (S3). For example, a message image indicating that the YAG laser 35 is time for replacement is displayed on the screen of the LCD 72. When the CPU 51 determines that the driving time of the YAG laser 35 does not exceed 100% of the rated life (S2: No), it is determined whether or not the driving time of the YAG laser 35 exceeds 80% of the rated life. (S4: Yes), each drive current value set in the drive current value determination table 52a (FIG. 4 (a)) is set to a larger drive current value. Correction is performed (S5). Subsequently, the CPU 51 executes the temperature control process described in the first embodiment (S6 to S14 in FIG. 6).
That is, the CPU 51 changes the drive current value set by the drive current value determination table 52a (FIG. 4A) in accordance with the change over time of the YAG laser 35, and the excitation semiconductor corresponding to the changed drive current value. The optimum temperature y of the laser is determined based on Equation 1. Note that 80%, which is the determination threshold in S4, can be changed to other ratios such as 70% and 90%.

[Effects of Second Embodiment]
As described above, when the laser beam irradiation apparatus 1 of the second embodiment is implemented, the drive current supplied to the pumping semiconductor laser 28 even when the YAG laser 35 changes with time and the output power decreases. Since the intensity of the pumping light emitted from the pumping semiconductor laser 28 to the YAG laser 35 is changed by changing the current value, the output power (oscillation efficiency) of the laser light in the YAG laser 35 is changed. Thus, it is possible to prevent the output power from being lowered as the YAG laser 35 changes with time.
Furthermore, even when the drive current value set in the drive current value determination table 52a is changed as described above, the temperature of the pumping semiconductor laser 28 corresponding to the changed drive current value is expressed by Equation 1. Therefore, the output power of the laser beam can be increased.
Therefore, if the laser beam irradiation apparatus 1 of the second embodiment is implemented, the print quality of the object can be stabilized even when the YAG laser 35 changes with time.

<Other embodiments>
(1) The temperatures of the pumping semiconductor laser 28 and the YAG laser 35 can be controlled by an air cooling fan or a water cooling heat sink instead of the Peltier element.
(2) A YLF laser, a YVO ₄ laser, a YAlO ₃ laser, or the like can be used instead of a YAG laser as a laser medium.
(3) The laser beam irradiation apparatus of the present invention can also be applied to perform processing such as drilling and cutting by irradiating an object with laser beam.

[Correspondence with Claims]
The laser driver 29 corresponds to the drive current supply unit, the temperature detection control unit 34a and the CPU 51 correspond to the temperature control unit, the ROM 53 corresponds to the storage unit, and the drive current value determination table 52a corresponds to the drive current value setting unit. A print target material selection screen 72a corresponds to the display unit. S6 to S12 executed by the CPU 51 correspond to the temperature determination process, and S13 and S14 correspond to the temperature control process. In the second embodiment, S1 to S12 executed by the CPU 51 correspond to the temperature determination process.

DESCRIPTION OF SYMBOLS 1 Laser beam irradiation apparatus 3 Laser controller 5 Power supply part 6 Print target object 7 PC
11 Printing Laser Oscillator 18 Galvano Scanner 19 fθ Lens 28 Excitation Semiconductor Laser 29 Laser Driver 31 Power Supply 33 Optical Fibers 34a, 34b Temperature Detection Control Unit 35 YAG Laser 36, 37 Temperature Sensor 38, 39 Peltier Element 51 CPU
52a Drive current value determination table 53 ROM
72a Print target material selection screen

Claims (7)

A laser light irradiation apparatus for irradiating and processing a laser beam on an object,
An excitation semiconductor laser that irradiates excitation light having an intensity corresponding to the current value of the drive current flowing through the device;
A drive current supply unit for supplying the drive current to the semiconductor laser for excitation;
A drive current value setting unit for setting a current value of the drive current;
A laser medium that is excited by the excitation light and oscillates the laser light;
A temperature control unit for controlling the temperature of the semiconductor laser for excitation to a predetermined temperature;
A storage unit storing a correspondence relationship between the temperature of the pumping semiconductor laser when the oscillation efficiency of the laser beam is maximized and the current value of the drive current;
The temperature controller is
A temperature determination process for determining a temperature of the excitation semiconductor laser corresponding to the current value of the drive current set by the drive current value setting unit based on the correspondence relationship stored in the storage unit;
And a temperature control process for controlling the temperature of the pumping semiconductor laser so that the temperature is determined by the temperature determination process. The correspondence relationship is
The characteristic indicating the change in the oscillation efficiency of the laser beam with respect to the temperature change of the semiconductor laser for excitation is based on a measurement result measured for each current value of the drive current, and based on the measurement result, 2. The laser beam irradiation according to claim 1, wherein the temperature of the pumping semiconductor laser when the oscillation efficiency is maximized is obtained by associating with each current value of the driving current. apparatus. The correspondence is defined by a linear function with the current value of the drive current as a variable,
In the temperature determination process,
The temperature of the pumping semiconductor laser corresponding to the current value of the drive current set by the drive current value setting unit is determined by calculation using the linear function. Item 3. A laser beam irradiation apparatus according to Item 2. The temperature range of the semiconductor laser for excitation defined in the correspondence relationship is
4. The laser light irradiation apparatus according to claim 1, wherein the laser light irradiation device is in a temperature range of the excitation semiconductor laser when the object is processed by the laser light. 5. A display unit on which the type of the object to be processed is displayed so as to be selectable;
In the drive current value setting unit,
The type of the object and the current value of the driving current suitable for processing are associated with each type of the object,
The temperature determination process includes
The current value of the drive current associated with the type of the object selected by the display unit is selected from the drive current value setting unit, and the excitation current corresponding to the current value of the selected drive current is selected. The laser beam irradiation apparatus according to claim 1, wherein the temperature of the semiconductor laser is determined based on the correspondence relationship.   The temperature determination process changes the current value of the drive current set by the drive current value setting unit according to a change with time of the laser medium, and the excitation semiconductor corresponding to the changed current value of the drive current 6. The laser beam irradiation apparatus according to claim 1, wherein a laser temperature is determined based on the correspondence relationship.   The laser light irradiation apparatus according to claim 1, wherein the temperature control unit includes a Peltier element that controls the temperature of the pumping semiconductor laser.

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