JP4036179B2 - Laser marking device - Google Patents

Description

  The present invention relates to a laser marking device that performs marking using line light from a laser beam.

2. Description of the Related Art Conventionally, there has been provided a laser marking device that performs marking using line light generated by laser light (see, for example, Patent Document 1).
JP 2002-131055 A

  Conventional laser marking devices are provided with adjusting means for adjusting the output of the semiconductor laser in the manufacturing stage to adjust the rated output of the semiconductor laser within a predetermined range. Although the rated output of the laser beam was adjusted within a certain range using the above, there was no one provided with a function for adjusting the light amount of the laser beam on the user side.

  By the way, the laser marking device is used in places with various brightnesses. If the light intensity of the semiconductor laser is adjusted so that the laser beam can be seen even in a bright place, the laser marking device is darkened. When used in a place, there is a problem that the line light from the laser light becomes thick and the accuracy of inking is lowered. Further, when the amount of laser light is too bright, there is a problem that eyes are tired when working for a long time. Further, when the light amount of the semiconductor laser is adjusted to be dark so as to be suitable for use in a dark place, there is a problem that the line light from the laser beam cannot be seen when used in a bright place.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a laser marking device in which the user can adjust the amount of light according to the brightness of the site.

In order to achieve the above object, the invention of claim 1 is directed to a light output unit that outputs laser light for inking, and a monitor signal having an electrical quantity corresponding to the amount of laser light output from the light output unit. The output light monitor unit, the monitor signal conversion unit that converts the monitor signal into a voltage signal proportional to the amount of electricity, the command voltage generation unit that generates the light amount command voltage that is the light amount command value, and the light amount command voltage are divided. A reference voltage comprising voltage dividing means for generating a reference voltage by pressure, and a light output adjusting means for adjusting a rated output of the light output unit within a predetermined range by adjusting a voltage dividing ratio of the voltage dividing means on the manufacturer side And a laser drive unit that feedback-controls the output of the optical output unit so that the output voltage of the monitor signal conversion unit matches the reference voltage. The command voltage generation unit is a variable resistor that can be operated on the user side. and a fixed resistance Comprising a voltage divider circuit comprising a series circuit, and outputs a voltage obtained by dividing the constant voltage of the constant voltage source in the voltage dividing circuit as the light intensity command voltage.

  According to a second aspect of the present invention, in the first aspect of the present invention, the command voltage generating unit is provided with a command voltage limiting unit that limits the light amount command voltage to a predetermined maximum value or less.

  According to a third aspect of the present invention, in the second aspect of the present invention, the command voltage limiting unit includes a maximum command voltage generating unit that generates a maximum command voltage that is a maximum value of the light amount command voltage, and a predetermined value lower than the maximum command voltage. If the divided voltage by the voltage dividing circuit does not exceed the threshold voltage, the divided voltage is output as a light amount command voltage, and if the divided voltage exceeds the threshold voltage, the maximum command voltage is used as the light amount command voltage. It is characterized by comprising a command voltage switching unit for outputting.

  According to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, the constant voltage source and the driving power source of the optical output unit are composed of separate power sources.

As described above, according to the first aspect of the invention, the constant voltage of the constant voltage source is divided apart from the light output adjusting means for adjusting the light quantity of the laser beam within a certain range on the maker side in the manufacturing stage. The voltage dividing circuit for generating the light quantity command voltage is provided, and the voltage dividing ratio of the voltage dividing circuit composed of the variable resistor and the fixed resistor is changed by changing the resistance value of the variable resistor constituting the voltage dividing circuit. Since the light quantity command voltage obtained by dividing and dividing the constant voltage of the constant voltage source changes, the reference voltage obtained by dividing the light quantity command voltage by the reference voltage generation unit can be changed. Therefore, the laser drive unit performs feedback control so that the output of the monitor signal conversion unit matches this reference voltage, so that the amount of laser light output from the light output unit can be changed. The brightness of the laser beam can be changed according to the place of use.

  In the invention of claim 2, since the light amount command voltage is limited to a predetermined maximum value or less by the command voltage limiting unit, an upper limit value is set to a reference voltage obtained by dividing the light amount command voltage, and the light output unit An upper limit is set for the laser output, and it is possible to prevent the laser output from becoming excessive.

  Further, in the invention of claim 3, when the divided voltage of the voltage dividing circuit exceeds a predetermined threshold voltage lower than the maximum command voltage, the command voltage switching unit outputs the maximum command voltage as the light amount command voltage. The reference voltage obtained by dividing the light amount command voltage is the maximum voltage value, and the laser output of the light output unit can be the maximum output.

  In addition, if the power source of the command voltage generation unit and the drive power source of the light output unit are the same power source, the laser light will disappear, so the light amount command voltage cannot be lowered below the minimum drive voltage of the light output unit. In the invention of claim 4, since the constant voltage source and the drive power source of the light output unit are separate power sources, the light amount command voltage can be set to an arbitrary voltage, and can be lowered to the minimum drive voltage or less of the light output unit. .

  Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 is a block diagram of this embodiment. This laser marking device includes a semiconductor laser module 1, a laser drive circuit block 2, a light amount adjustment circuit block 3, a maximum command voltage generation circuit block 4, and a command voltage. The switching circuit block 5 is provided as a main configuration, and the command voltage generation unit 6 is configured by the light amount adjustment circuit block 3, the maximum command voltage generation circuit block 4, and the command voltage switching circuit block 5.

  The semiconductor laser module 1 receives a laser diode 1a (light output unit) that outputs a laser beam in response to a drive current I1 supplied from the laser drive circuit block 2, and a laser beam output from the laser diode 1a. A monitor diode 1b (light monitor unit) that generates a monitor current I2 having a magnitude proportional to the amount of laser light is housed in one module.

  FIG. 2 is a block diagram showing an example of the laser drive circuit block 2. The laser drive circuit block 2 converts the monitor current I2 flowing through the monitor diode 1b into a voltage signal V4 having a voltage value corresponding to the current value. -Voltage dividing circuit 2a (monitor signal converting unit) and voltage dividing ratio of voltage dividing circuit 2b and voltage dividing circuit 2b for generating reference voltage V3 by dividing light quantity command voltage V2 inputted from command voltage switching circuit block 5 A reference voltage generation circuit 2f having an optical output adjustment unit 2e for adjusting the difference, a differential amplifier 2c for amplifying a difference between the output voltage V4 of the current-voltage conversion circuit 2a and the reference voltage V3, and a differential amplifier 2c Is supplied to the control terminal, and a power element 2d that supplies a driving current I1 having a magnitude proportional to the output voltage of the differential amplifier 2c to the laser diode 1a; Provided. Here, the differential amplifier 2c and the power element 2d constitute a laser drive unit that feedback-controls the output of the laser diode 1a.

  Here, a specific circuit of the laser drive circuit block 2 will be described with reference to FIG. The current-voltage conversion circuit 2a includes a resistor R11. When the monitor current I2 from the monitor diode 1b flows through the resistor R10, the voltage signal V4 generated between both ends of the resistor R10 is output to the differential amplifier 2c. The voltage dividing circuit 2b is composed of a series circuit of a variable resistor VR2 and resistors R9 and R10, and outputs the voltage at the connection point of the resistors R9 and R10 as a reference voltage V3 to the differential amplifier 2c. The power element 2d is made of, for example, a transistor, and the voltage of the drive power supply Vcc is applied to a series circuit of the laser diode 1a, the power element 2d, and the resistor R13. The output terminal of the differential amplifier 2c is connected to the control terminal of the power element 2d via the resistor R12, and the differential amplifier 2c is configured so that the output voltage V4 of the current-voltage conversion circuit 2a matches the reference voltage V3. The power element 2d is controlled.

  Here, when the light quantity command voltage V2 input from the command voltage switching circuit block 5 is constant, the variable resistance VR2 as the light output adjustment unit 2e is operated to change the voltage dividing ratio of the voltage dividing circuit 2b. The voltage value of the reference voltage V3 obtained by dividing the light quantity command voltage V2 by the voltage circuit 2b changes, and the drive supplied from the power element 2d so that the output of the current-voltage conversion circuit 2a matches this reference voltage V3. Since the current I1 is controlled, the power supplied to the laser diode 1a is increased or decreased, and the amount of laser light is controlled. The light output adjusting unit 2e is for adjusting the rated output of the laser light within a predetermined range on the manufacturer side in the manufacturing stage, and the amount of the laser light is changed by changing the voltage dividing ratio of the voltage dividing circuit 2b. Adjustment can be made within a predetermined range. The light output adjusting unit 2e is arranged inside the outer shell (not shown) of the laser marking device and cannot be operated from the outside of the outer shell. The amount of laser light cannot be changed by operation.

  Next, the circuit configuration of the command voltage generation unit 6 including the light amount adjustment circuit block 3, the maximum command voltage generation circuit block 4, and the command voltage switching circuit block 5 will be described with reference to the specific circuit diagram of FIG. The circuit configuration of the light amount adjustment circuit block 3, the maximum command voltage generation circuit block 4, and the command voltage switching circuit block 5 is not intended to limit the circuit configuration to the circuit of FIG. 3, but for example, a D / A converter provided in a microcomputer, It can also be realized using functions such as an A / D converter and PWM control.

  The light amount adjustment circuit block 3 is composed of a series circuit of a resistor R1, a variable resistor VR1, and a resistor R2 that divides a substantially constant power supply voltage Vref of a constant voltage source, and adjusts the voltage at the connection point between the resistor R1 and the variable resistor VR1. Output as voltage V1. Here, by increasing or decreasing the resistance value of the variable resistor VR1, the voltage dividing ratio determined by the resistance value of the resistor R1 and the combined resistance value of the variable resistor VR1 and the resistor R2 changes, and the voltage value of the light amount adjustment voltage V1. Changes. FIG. 4A is a diagram illustrating the relationship between the resistance value of the variable resistor VR1 and the light amount adjustment voltage V1, and as the resistance value of the variable resistor VR1 increases, the voltage dividing ratio increases and the light amount adjustment voltage V1 increases.

  The maximum command voltage generation circuit block 4 is composed of a series circuit of resistors R3 and R4 that divide a constant voltage Vref of a constant voltage source, and varies by dividing the voltage Vref of the constant voltage source by high-precision resistors R3 and R4. A constant maximum command voltage Vmax with a small value is generated. FIG. 4B is a diagram showing the relationship between the resistance value of the variable resistor VR1 and the maximum command voltage Vmax. The maximum command voltage Vmax is a substantially constant value regardless of the increase or decrease in the resistance value of the variable resistor VR1.

  The command voltage switching circuit block 5 includes a multiplexer MPX in which the light amount adjustment voltage V1 of the light amount adjustment circuit block 3 and the maximum command voltage Vmax of the maximum command voltage generation circuit block 4 are input to input terminals CH1 and CH0, respectively, and resistors R5 and R6. A threshold voltage generating circuit 5a that divides a constant voltage Vref of a constant voltage source to generate a threshold voltage V5, and a comparator CP that compares the levels of the output voltage V1 and the threshold voltage V5 of the light amount adjusting circuit block 3 And a transistor T1 having a base terminal connected to the output terminal of the comparator CP via a resistor R7, an emitter connected to the circuit ground, and a collector connected to the control terminal A of the multiplexer MPX. The output terminal OUT voltage V2 is used as the light quantity command voltage for the laser drive circuit. It is supplied to the block 2. Note that the collector terminal of the transistor T1 is pulled up to a constant voltage Vcc via a resistor R8.

  Here, in the threshold voltage generation circuit 5a, the constant voltage Vref of the constant voltage source is divided by the high-precision resistors R5 and R6, whereby the constant threshold voltage V5 that is lower than the maximum command voltage Vmax and has little variation is obtained. Generate. The comparator CP compares the light intensity adjustment voltage V1 input from the light intensity adjustment circuit block 3 with the threshold voltage V5. If the light intensity adjustment voltage V1 does not exceed the threshold voltage V5, the output of the comparator CP is at L level. Thus, the transistor T1 is turned off, and the voltage at the control terminal A of the multiplexer MPX becomes H level. The multiplexer MPX outputs the voltage at the input terminal CH1 from the output terminal OUT when the voltage at the control terminal A is H level, and outputs the voltage at the input terminal CH0 from the output terminal OUT when the voltage at the control terminal A is L level. Therefore, when the light amount adjustment voltage V1 is lower than the threshold voltage V5, the light amount adjustment voltage V1 input to the input terminal CH1 is output from the output terminal OUT. On the other hand, when the light amount adjustment voltage V1 input from the light amount adjustment circuit block 3 exceeds the threshold voltage V5, the output of the comparator CP becomes H level, the transistor T1 is turned on, and the voltage at the control terminal A of the multiplexer MPX is changed. Since it is at the L level, the maximum command voltage Vmax input to the input terminal CH0 is output from the output terminal OUT.

  FIG. 4C is a diagram showing the relationship between the resistance value of the variable resistor VR1 and the light amount command voltage V2 output from the command voltage switching circuit block 5. In the range where the light amount adjustment voltage V1 is lower than the threshold voltage V5, the light amount The command voltage V2 is the light amount adjustment voltage V1, and the light amount command voltage V2 is the maximum command voltage Vmax when the light amount adjustment voltage V1 is higher than the threshold voltage V5.

  As described above, in the present embodiment, the light amount adjustment circuit block 3 for dividing the constant voltage of the constant voltage source to generate the light amount adjustment voltage V1 is provided separately from the light output adjustment unit 2e. Since the voltage dividing ratio of the light amount adjustment circuit block 3 is changed and the light amount adjustment voltage V1 is changed by changing the resistance value of the variable resistor VR1 forming the variable resistor VR1, the variable amount is variable in a range where the light amount adjustment voltage V1 does not exceed the threshold voltage V5. By changing the resistance value of the resistor VR1, the light amount command voltage V2 can be changed, and the reference voltage V3 obtained by dividing the light amount command voltage V2 by the voltage dividing circuit 2b can be changed. The amount of laser light output from the laser diode 1a can be changed by feedback control so that the output voltage V4 of the current-voltage conversion circuit 2a matches the reference voltage V3. The brightness of the laser beam can be changed according to the place of use.

  Further, when the light amount adjustment voltage V1 exceeds a predetermined threshold voltage V5 lower than the maximum command voltage Vmax, the command voltage switching circuit block 5 outputs the maximum command voltage Vmax as the light amount command voltage V2. Therefore, the light amount command voltage at this time The reference voltage V3 obtained by dividing V2 is the maximum voltage value, and the laser output output from the laser diode 1a can be the maximum output. Further, since the light amount command voltage V2 is limited to the maximum command voltage Vmax or less by the command voltage limiter configured by the maximum command voltage generation circuit block 4 and the command voltage switching circuit block 5, the light amount command voltage V2 is divided. The reference voltage V3 obtained in this manner can be limited to a predetermined upper limit value or less, and as a result, an upper limit is provided for the laser output output from the laser diode 1a, and the laser output can be prevented from becoming excessive.

  Further, when the power supply of the command voltage generator 6 and the drive power supply Vcc of the laser diode 1a are the same power supply, the laser light is extinguished, so that the light quantity command voltage V2 is lowered to the minimum drive voltage or less of the laser diode 1a. However, since the constant voltage source Vref of the command voltage generator 6 and the driving power source of the laser diode 1a are separate power sources in this embodiment, the light amount command voltage V2 can be set to an arbitrary voltage. It can also be lowered to below the minimum driving voltage of 1a.

It is a block diagram of this embodiment. It is a principal part block diagram same as the above. It is a specific circuit diagram of the principal part same as the above. (A) is a diagram showing the relationship between the resistance value of the variable resistor VR1 and the light amount adjustment voltage V1, (b) is a diagram showing the relationship between the resistance value of the variable resistor VR1 and the maximum command voltage Vmax. ) Is a diagram showing the relationship between the resistance value of the variable resistor VR1 and the light amount command voltage V2. It is a specific circuit diagram of the principal part same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Semiconductor laser module 1a Laser diode 1b Monitor diode 2 Laser drive circuit block 3 Light quantity adjustment circuit block 4 Maximum command voltage generation circuit block 5 Command voltage switching circuit block 6 Command voltage generation part I1 Drive current I2 Monitor current V1 Light quantity adjustment voltage V2 Light quantity Command voltage Vmax Maximum command voltage

Claims (4)

A light output unit that outputs laser light for inking, a light monitor unit that outputs a monitor signal of an amount of electricity corresponding to the amount of laser light output from the light output unit, and the monitor signal is proportional to the amount of electricity A monitor signal conversion unit for converting into a voltage signal, a command voltage generation unit for generating a light amount command voltage that is a light amount command value, a voltage dividing means for dividing the light amount command voltage to generate a reference voltage, The reference voltage generator comprising optical output adjusting means for adjusting the rated output of the optical output part within a predetermined range by adjusting the voltage dividing ratio of the pressure means on the maker side, and the output voltage of the monitor signal converting part to the reference voltage A laser drive unit that feedback-controls the output of the optical output unit so as to match, and the command voltage generation unit includes a voltage dividing circuit including a series circuit of a variable resistor and a fixed resistor that can be operated on the user side. This partial pressure Laser marking instrument and outputs a voltage obtained by dividing the constant voltage of the constant voltage source in the road as the light intensity command voltage.   2. The laser marking device according to claim 1, wherein the command voltage generating unit is provided with a command voltage limiting unit that limits the light amount command voltage to a predetermined maximum value or less.   The command voltage limiting unit includes a maximum command voltage generation unit that generates a maximum command voltage that is a maximum value of the light amount command voltage, and a divided voltage by the voltage dividing circuit exceeds a predetermined threshold voltage that is lower than the maximum command voltage. Otherwise, the divided voltage is output as a light amount command voltage, and when the divided voltage exceeds the threshold voltage, the command voltage switching unit is configured to output the maximum command voltage as the light amount command voltage. The laser marking device according to claim 2.   The laser marking device according to any one of claims 1 to 3, wherein the constant voltage source and the driving power source of the light output unit are separate power sources.

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