JP2009131876A - Laser beam machining apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To adjust the power of a laser output emitted to a workpiece in linearity without monitoring a part of the laser beam emitted from a laser oscillator while evading the increase of the number of components, the raising of cost and the complication of structure. <P>SOLUTION: In the laser marking apparatus 1, when a user sets a desired value as the power of a laser output by operating an operation device 8, the power of the laser output corresponding to the value set by the user is derived on the basis of a corresponding relation between a set value and the power of the laser output stored in a storage device 9. Then, on the basis of a corresponding relation between a 1/2 wavelength plate angle and the power of the laser output stored in the storage device 9, a 1/2 wavelength plate angle is derived corresponding to the power of the laser output derived, and the 1/2 wavelength plate 3 is rotated to coincide with the turning angle so derived. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a laser processing apparatus that performs processing by irradiating a workpiece with laser light.

  Conventionally, there has been provided a laser processing apparatus that performs processing by irradiating an object to be processed with laser light. A laser marking device, one of the laser processing devices, has a wide variety of characters, symbols, and figures on the surface of a workpiece (work) made of various materials such as metal, resin, ceramic, semiconductor, paper, and glass. It is for marking. Such a laser marking device is capable of adjusting the power of laser light emitted from a laser oscillator according to the type of material of the processing object, and by adjusting the power of the laser light, the processing object Marking is possible with the optimum marking concentration according to the type of material. In a laser oscillator that emits laser light based on an oscillation condition determined by current and oscillation frequency, the power of the laser light is generally adjusted by changing the oscillation condition described above.

  By the way, there is a machine difference (individual difference) in the power of the laser light emitted from the laser oscillator, and the laser output irradiated to the object to be processed from the laser marking device due to the machine difference in the laser light power of the laser oscillator. Variations in power. Therefore, when a plurality of laser marking devices uniformly mark a plurality of workpieces of the same type, the plurality of laser marking devices are used in order to eliminate variations in power of laser output in the plurality of laser marking devices. It is necessary to adjust the power of the laser beam for each laser oscillator.

  However, there is a problem that the operation of adjusting the power of the laser beam for each laser oscillator of the plurality of laser marking apparatuses is very complicated. In addition, by controlling the excitation LD current, it is possible to eliminate mechanical differences in the power of the laser light emitted from the laser oscillator, but the characteristics such as beam quality and divergence angle change, so marking It becomes difficult to maintain quality.

Therefore, in order to solve the above-mentioned problems, a quarter wavelength plate for rotating the polarization plane of the laser beam emitted from the laser oscillator is provided, and a part of the laser beam branched by the beam splitter is received by the photodetector. In this configuration, the wave plate is rotated and controlled so that the detected received light amount becomes a desired value. According to such a configuration, the power of the laser light emitted from the laser oscillator is controlled. By controlling the rotation of the quarter-wave plate without requiring adjustment work, it is possible to set the power of the laser output applied to the object to be processed from the laser marking device to a desired value (Patent Document). 1).
Japanese Patent Laid-Open No. 11-097782

  However, in the above-described Patent Document 1, a beam splitter that branches a laser beam emitted from a laser oscillator and a part of the laser beam branched by the beam splitter are received to detect a received light amount. There is a problem that a photodetector is required, the number of parts is increased, the cost is increased, and the configuration is complicated. In addition, there is a problem that a waste of monitoring a part of the laser beam originally used for processing occurs.

  On the other hand, in Japanese Patent Application No. 2006-099060 filed by the present applicant, the power of the laser output passing through the polarizing member is adjusted by changing the relative rotation angle between the half-wave plate and the polarizing member. ing. However, this does not automatically set the power of the laser output that passes through the polarizing member, but automatically sets the power of the laser output that passes through the polarizing member based on a setting value set by the user. It is necessary to measure and store in advance the correspondence between the amount of change in the relative rotation angle between the half-wave plate and the polarizing member and the power of the laser output. It is necessary to measure the correspondence between the change amount of the relative rotation angle and the power of the laser output, which is troublesome.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to avoid an increase in the number of parts, an increase in cost, and a complicated configuration, and a part of laser light emitted from a laser oscillator. An object of the present invention is to provide a laser processing apparatus capable of adjusting the power of laser output irradiated to a processing object to linearity without monitoring the above.

  The laser processing apparatus according to claim 1, wherein a laser oscillator that emits laser light based on an oscillation condition determined by a current and an oscillation frequency, and the optical axis on the optical axis of the laser light emitted from the laser oscillator Polarization means for passing only laser light in a predetermined polarization direction out of the same laser light according to the relative rotation angle of the polarization plane with the laser oscillator about the axis along the axis, and the laser oscillator and the polarization means A laser processing apparatus comprising: a control unit that adjusts the power of a laser output for irradiating the processing object through the polarizing unit by rotating at least one of the rotating unit with the rotating unit. , The correspondence between the setting means (P) and the relative rotation angle (θ) operated by the user to set a setting value corresponding to the power of the laser output, and P = (co storage means for storing as θ + 1) / 2, wherein the control means derives a relative rotation angle according to an operation amount of the user by the operation means from a correspondence relationship stored in the storage means, At least one of the laser oscillator and the polarization unit is rotated by the rotation unit so that the relative rotation angle of the polarization plane of the laser oscillator and the polarization unit becomes the derived relative rotation angle. It has the characteristic in having comprised.

  The laser processing apparatus according to claim 2, wherein the polarization unit passes the wave plate that changes a polarization direction of the laser light according to a relative rotation angle of a polarization plane with the laser oscillator, and the wave plate. The polarization direction of the laser light is changed according to the relative rotation angle of the polarization plane with the wave plate about the axis along the optical axis on the optical axis of the laser light, and a predetermined one of the laser lights A polarization member that allows only laser light in the polarization direction to pass therethrough, and the control means derives a relative rotation angle according to an operation amount of the user by the operation means from a correspondence relationship stored in the storage means. Rotating means for rotating at least one of the laser oscillator, the wavelength plate, and the polarizing member so that the relative rotational angle of the polarization plane of the laser oscillator and the polarizing means becomes the derived relative rotational angle. Rotate by Characterized in was sea urchin configuration.

  The laser processing apparatus according to claim 3, wherein the control unit derives a relative rotation angle corresponding to an operation amount of the user by the operation unit from a correspondence relationship stored in the storage unit, and the laser oscillator The polarizing plate is rotated only so that the relative rotation angle of the polarization plane with the polarizing means becomes the derived relative rotation angle.

  According to the laser processing apparatus of the first aspect, when the user operates the operation unit to set a desired set value (P) as the laser output power, the control unit responds to the operation amount by the user operation unit. The relative rotation angle (θ) is derived from the correspondence relationship P = (cos θ + 1) / 2 stored in the storage means, and the relative rotation angle of the polarization plane between the laser oscillator and the polarization means is the derived relative value. At least one of the laser oscillator and the polarization unit is rotated by the rotation unit so that the rotation angle is obtained.

  As a result, a conventional beam splitter that splits the laser beam emitted from the laser oscillator and a photodetector that detects the amount of light received by receiving a part of the laser beam branched by the beam splitter is required. In contrast, since the beam splitter and photodetector are not required, an increase in the number of components, an increase in cost, and a complicated configuration can be avoided, and a part of the laser light emitted from the laser oscillator can be monitored. In addition, the power of the laser output irradiated to the workpiece can be adjusted to linearity. Further, the setting accuracy of the laser output power can be increased in accordance with the resolution with which the user sets the set value.

  According to the laser processing apparatus of claim 2, the polarization means includes a wave plate that changes the polarization direction of the laser light according to the relative rotation angle of the polarization plane with the laser oscillator, and a laser that has passed through the wave plate. The polarization direction of the laser beam is changed according to the relative rotation angle of the polarization plane with the wave plate centering on the axis along the optical axis on the optical axis of the light, and the predetermined polarization direction of the laser beam is changed And a polarizing member that allows only the laser beam to pass therethrough. In this case, when the user operates the operation unit to set a desired set value (P) as the laser output power, the control unit sets the relative rotation angle (θ) according to the operation amount by the user operation unit, The laser oscillator is derived from the correspondence relationship P = (cos θ + 1) / 2 stored in the storage means, and the relative rotation angle of the polarization plane between the laser oscillator and the polarization means is the derived relative rotation angle. At least one of the wave plate and the polarizing member is rotated by the rotating means. Thereby, the power of the laser output irradiated to the workpiece can be adjusted to linearity by rotating at least one of the laser oscillator, the wave plate, and the polarizing member.

  According to the laser processing apparatus of the third aspect, when the user operates the operation means to set a desired set value (P) as the laser output power, the control means rotates only the wavelength plate. Thereby, the power of the laser output irradiated to the workpiece can be adjusted to linearity by rotating only the wave plate. In particular, in this case, by rotating only the wave plate, the polarization direction of the laser light emitted from the laser processing apparatus can always be kept at a predetermined polarization direction, and the processing quality can be improved even if the laser output is changed. Can be kept constant.

(First embodiment)
A first embodiment in which the present invention is applied to a laser marking device will be described below with reference to FIGS. FIG. 1 schematically shows the configuration of a laser marking device. The laser marking device 1 includes a laser oscillator 2, a half-wave plate 3 (polarization means and wavelength plate as used in the present invention), a polarizing plate 4 (polarization means and polarization member as used in the present invention), and a rotation device 5 (the present invention). Rotating means), a damper 6, a control device 7 (control means according to the present invention), an operating device 8 (operating means according to the present invention), and a storage device 9 (storage means according to the present invention). ing.

  The laser oscillator 2 emits laser light based on the oscillation condition determined by the current and the oscillation frequency. The laser oscillator 2 has constant oscillation conditions and constant laser beam power. The constant oscillation condition is a specific oscillation condition in which the power of the laser beam is quickly stabilized at a desired value. The laser oscillator 2 emits laser light having a wavelength in the visible region, and the wavelength is set to 532 [nm].

  The half-wave plate 3 is provided on the optical axis of the laser beam emitted from the laser oscillator 2 so as to be rotatable about the axis along the optical axis, and the rotation angle (polarization plane with the laser oscillator 2). The polarization direction (orientation) of the laser light is changed in accordance with the relative rotation angle. The half-wave plate 3 is rotated by, for example, “0 ° to 45 °”, so that the angle of the polarization plane of linearly polarized light (laser light emitted from the laser oscillator 2) is “0 ° to 90 °”. The horizontal linearly polarized light is changed to the vertical linearly polarized light.

  The polarizing plate 4 is configured by supporting (sandwiching) a needle-like crystal with a transparent base made of glass, for example, on the optical axis of the laser beam that has passed through the half-wave plate 3 described above. And the polarization direction (orientation) of the laser beam is changed according to the rotation angle (the relative rotation angle of the polarization plane with the half-wave plate 3). Of the laser light, only laser light having a predetermined polarization direction is allowed to pass, and the laser light is reflected in a preset reflection direction without passing laser light having a direction other than the predetermined polarization direction.

  The damper 6 is made of, for example, a matte black metal in order to absorb the laser light satisfactorily, and is disposed in a reflection direction in which the laser light is reflected by the polarizing plate 4, and the laser light reflected by the polarizing plate 4. To absorb.

  The rotation device 5 includes a motor serving as a drive source capable of rotating the half-wave plate 3 and the polarizing plate 4 described above, and is supplied with a drive current so that the half-wave plate 3 and the polarization plate are supplied. The plate 4 is rotated. In this case, an internal adjustment mechanism that cannot be operated from the outside for setting the polarization direction of the laser light to the reference direction by rotating at least one of the half-wave plate 3 and the polarizing plate 4 is provided. Yes. That is, during the manufacture of the laser marking device 1, an assembly error or the like occurs between each of the laser oscillator 2, the half-wave plate 3 and the polarizing plate 4, and a desired value is obtained as the power of the laser output that has passed through the polarizing plate 4. In the case where it cannot be obtained, the above-described internal adjustment mechanism is operated to rotate the half-wave plate 3 or the polarizing plate 4 to obtain a desired value. The reference direction described above is a direction based on the laser beam emitted from the laser oscillator 2 provided so as not to rotate.

The operation device 8 is configured to be operable by a user to set a set value. As shown in FIG. 2, the storage device 9 has a correspondence relationship between the set value and the laser output power, and a correspondence between the half-wave plate angle (the rotation angle of the half-wave plate 3) and the laser output power. I remember the relationship. The correspondence between the set value and the power of the laser output is a directly proportional relationship. The correspondence between the half-wave plate angle and the power of the laser output is that of the cos function. Specifically, the laser output power is “P”, the rotation angle of the half-wave plate 3 is “θ”, and the maximum laser output power (laser output power when θ = 0) is “P _max ”. "
P = P _max · (cos θ + 1) / 2
And
θ = cos ⁻¹ (2P / P _max −1)
It becomes.

In the present embodiment, since “P” that is the power of the laser output is described as an absolute physical quantity having a specific unit (for example, [W]), the term “(cos θ + 1) / 2” The term “P _max ” which is the maximum power of the laser output which is a physical quantity having the same unit as “P” is multiplied. On the other hand, when the set value for setting the power of the laser output is a relative amount having no unit, “P _max ” can be calculated as “1”, that is,
P = (cos θ + 1) / 2
And
θ = cos ⁻¹ (2P−1)
It becomes.

  When the setting value set by the user is input from the operating device 8 when the user operates the operating device 8 to set the setting value, the control device 7 stores the setting value stored in the storage device 9 and the laser output. The power of the laser output corresponding to the set value set by the user is derived based on the correspondence with the power of the laser, and the correspondence between the half-wave plate angle stored in the storage device 9 and the power of the laser output is subsequently obtained. Based on the relationship, the rotation angle of the half-wave plate 3 corresponding to the derived laser output power is derived. Then, the control device 7 outputs a rotation command signal to the rotation device 5 and rotates the half-wave plate 3 by the derived rotation angle.

  In this embodiment, as shown in FIG. 2, for example, when there is a machine difference (individual difference) of “6 W to 8 W” in the power of the laser light emitted from the laser oscillator 2, the maximum of the emitted laser light In the laser marking apparatus 1 including the laser oscillator 2 having a power of “6 W”, as shown in FIG. 2A, in order to obtain “0 W to 6 W” as the laser output power, 1 / The two-wavelength plate 3 is rotated within a rotation range (all of the rotation range) of “0 ° to 45 °”, while the laser oscillator 2 having the maximum power of the emitted laser light of “8 W” is set. In the laser marking apparatus 1 provided, as shown in FIG. 2B, the half-wave plate 3 is set to “about 15 ° to about 0 ° to 6 W” as the laser output power. Rotation within 45 ° rotation range (part of rotation range) It would cause. The setting resolution of the rotating device 5 is, for example, 200 settings (0.5% to 100%), and a desired value can be obtained in units of “0.03 W” as the power of the laser output. In this embodiment, the setting value set by the user using the operation device 8 is a relative value (0% to 100%), but the laser output power ([W]) can be directly set. It may be. Moreover, the structure which can set a setting value with a dial scale (volume) type | formula may be sufficient as the operating device 8.

  The galvanometer mirror 10 is disposed between the polarizing plate 4 and the workpiece 11 and is driven by a driving source such as a motor that is drivingly connected. The driving speed is set in advance after starting the driving. It is configured to accelerate until reaching a certain driving speed, that is, at the writing portion when marking. When the driving speed of the galvanometer mirror 10 is accelerating until the driving speed of the galvano mirror 10 reaches a constant driving speed, the rotating device 5 described above is configured so that the power of the laser output gradually increases to a set value set by the user. The two-wave plate 3 is rotated. In other words, when the driving speed of the galvano mirror 10 is accelerating until the driving speed of the galvano mirror 10 reaches a certain driving speed, the rotating device 5 is set to 1 so that the marking density on the workpiece 11 is uniform at all locations. / 2 The wavelength plate 3 is rotated. As a result, the laser output that has passed through the polarizing plate 4 is irradiated onto the workpiece 11 via the galvano mirror 10, and a wide variety of characters, symbols, figures, and the like are marked.

  By the way, although the case where only the half-wave plate 3 was rotated was demonstrated above, both the half-wave plate 3 and the polarizing plate 4 may be rotated, and only the polarizing plate 4 is rotated. May be. Further, at least one of the laser oscillator 2, the half-wave plate 3, and the polarizing plate 4 may be rotated by configuring the laser oscillator 2 to be rotatable.

  As described above, according to the first embodiment, when the user operates the operation device 8 to set a desired value as the laser output power in the laser marking device 1, it is stored in the storage device 9. Based on the correspondence between the set value and the laser output power, the laser output power corresponding to the set value set by the user is derived, and then the half-wave plate angle stored in the storage device 9 Based on the correspondence with the laser output power, a half-wave plate angle corresponding to the derived laser output power is derived, and the half-wave plate 3 is rotated so that the derived rotation angle is obtained. Since it is configured to be moved, an increase in the number of parts, an increase in cost, and a complicated configuration are avoided, and irradiation of the workpiece is performed without monitoring a part of the laser light emitted from the laser oscillator 2. The power of the laser output can be adjusted to linearity being. Further, the setting accuracy of the laser output power can be increased in accordance with the resolution with which the user sets the set value.

  In this case, since only the half-wave plate 3 is rotated, the polarization direction of the laser light emitted from the laser marking device 1 can always be maintained at a predetermined polarization direction, and the laser output is changed. The marking quality can be kept constant.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. In addition, description is abbreviate | omitted about the same part as above-mentioned 1st Embodiment, and a different part is demonstrated. In the first embodiment described above, the power of the desired laser output is obtained by rotating the half-wave plate 3, but in the second embodiment, the polarizing member is rotated. By doing so, a desired laser output power can be obtained.

  That is, in the laser marking device 21, the polarizing plate 22 is provided on the optical axis of the laser light emitted from the laser oscillator 2 so as to be rotatable about the axis along the optical axis, and the rotation angle (laser oscillator) The polarization direction (direction) of the laser beam is changed according to the relative rotation angle of the polarization plane with respect to 2 and only the laser beam having a predetermined polarization direction is allowed to pass through the laser beam. The laser beam is reflected in a preset reflection direction without passing the laser beam. The rotation device 23 is composed of a motor serving as a drive source capable of rotating the polarizing plate 22 described above, and rotates the polarizing plate 22 when a driving current is supplied.

  In this case, the storage device 25 uses the correspondence between the half-wave plate angle and the laser output power instead of the correspondence relationship between the half-wave plate angle and the laser output power described in the first embodiment. Similar to the relationship, the correspondence relationship between the polarizing plate angle (rotation angle of the polarizing plate 22) and the power of the laser output in the correspondence relationship of the cos function is stored. Then, when the setting value set by the user is input from the operating device 8 by the user operating the operating device 8 to set the setting value, the control device 24 sets the setting value stored in the storage device 25 and The power of the laser output corresponding to the setting value set by the user is derived based on the correspondence with the power of the laser output, and then the correspondence between the polarizing plate angle stored in the storage device 25 and the power of the laser output. The rotation angle of the polarizing plate 22 corresponding to the derived power of the laser output is derived based on. Then, the control device 24 outputs a rotation command signal to the rotation device 23 and rotates the polarizing plate 22 by the derived rotation angle. In this case, at least one of the laser oscillator 2 and the polarizing plate 22 may be rotated by configuring the laser oscillator 2 to be rotatable.

  As described above, according to the second embodiment, in the laser marking device 21, when the user operates the operation device 8 to set a desired value as the power of the laser output, it is stored in the storage device 25. Based on the correspondence between the set value and the laser output power, the laser output power corresponding to the set value set by the user is derived, and then the polarizing plate angle and the laser output stored in the storage device 25 are derived. Since the polarizing plate angle corresponding to the derived laser output power is derived based on the correspondence relationship with the power, and the polarizing plate 22 is rotated so as to be the derived rotation angle, In the same manner as described in the first embodiment, an increase in the number of parts, an increase in cost, and a complicated configuration are avoided, and the laser beam emitted from the laser oscillator 2 is reduced. The without monitoring the power of the laser output emitted to the object can be adjusted in the linearity. Further, the setting accuracy of the laser output power can be increased in accordance with the resolution with which the user sets the set value.

(Other embodiments)
The present invention is not limited to the above-described embodiment, and can be modified or expanded as follows.
The laser oscillator 2 is not limited to emitting laser light having a wavelength in the visible region (532 [nm]), and may emit laser light having another wavelength (532 [nm]).
The polarizing plates 4 and 22 are not limited to glass bases, but may be made of, for example, quartz or resin. When the base is made of resin, the entire apparatus can be made cheaper than when the base is made of glass or quartz.

The configuration is not limited to an internal adjustment mechanism that sets the polarization direction of the laser light to the reference direction by rotating at least one of the half-wave plate 3 and the polarizing plates 4 and 22, for example, the laser oscillator 2. An internal adjustment mechanism that is configured to be rotatable and that sets the polarization direction of the laser light to a reference direction by rotating at least one of the laser oscillator 2, the half-wave plate 3, and the polarizing plates 4 and 22 is provided. It may be a configuration.
The structure which employ | adopts other wavelength plates, such as not only the 1/2 wavelength plate 3, but a 1/4 wavelength plate, may be sufficient.

Functional block diagram showing a first embodiment of the present invention The figure which shows the correspondence of a setting value and a laser output, and the correspondence of a 1/2 wavelength plate angle and a laser output Functional block diagram showing a second embodiment of the present invention

Explanation of symbols

  In the drawings, 1 is a laser marking device (laser processing device), 2 is a laser oscillator, 3 is a half-wave plate (polarizing means, wave plate), 4 is a polarizing plate (polarizing means, polarizing member), and 5 is rotating. Device (rotating means), 7 is a control device (control means), 8 is an operation device (operation means), 9 is a storage device (storage means), 11 is a workpiece, 21 is a laser marking device (laser processing device) , 22 is a polarizing plate (polarizing means, polarizing member), 23 is a turning device (turning means), 24 is a control device (control means), and 25 is a storage device (storage means).

Claims (3)

A laser oscillator that emits laser light based on an oscillation condition determined by a current and an oscillation frequency;
A predetermined polarization direction of the laser light is changed according to a relative rotation angle of a polarization plane with respect to the laser oscillator about the axis along the optical axis on the optical axis of the laser light emitted from the laser oscillator. Polarization means that allows only laser light to pass;
Control means for adjusting the power of the laser output for irradiating the object to be processed through the polarization means by rotating at least one of the laser oscillator and the polarization means by the rotation means. Laser processing equipment,
An operation means operated by a user to set a setting value corresponding to the power of the laser output;
Storage means for storing the correspondence between the set value (P) and the relative rotation angle (θ) as P = (cos θ + 1) / 2,
The control means derives a relative rotation angle corresponding to an operation amount of the user by the operation means from a correspondence relationship stored in the storage means, and relative rotation of a polarization plane between the laser oscillator and the polarization means. A laser processing apparatus, wherein at least one of the laser oscillator and the polarization unit is rotated by the rotation unit so that a moving angle becomes the derived relative rotation angle. The polarizing means includes a wave plate that changes a polarization direction of the laser beam according to a relative rotation angle of a polarization plane with the laser oscillator, and an optical axis on the optical axis of the laser beam that has passed through the wave plate. A polarizing member that changes the polarization direction of the laser beam in accordance with the relative rotation angle of the polarization plane with the wave plate about the axis along the axis and passes only the laser beam having a predetermined polarization direction out of the laser beam And
The control means derives a relative rotation angle corresponding to an operation amount of the user by the operation means from a correspondence relationship stored in the storage means, and relative rotation of a polarization plane between the laser oscillator and the polarization means. 2. The device according to claim 1, wherein at least one of the laser oscillator, the wavelength plate, and the polarizing member is rotated by a rotation unit so that a moving angle becomes the derived relative rotation angle. Laser processing equipment.   The control means derives a relative rotation angle corresponding to an operation amount of the user by the operation means from a correspondence relationship stored in the storage means, and relative rotation of a polarization plane between the laser oscillator and the polarization means. 3. The laser processing apparatus according to claim 2, wherein only the wave plate is rotated so that a moving angle becomes the derived relative rotation angle. 4.

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