JP2008221254A - Laser beam machining apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser beam machining apparatus that can perform stable laser oscillation by suppressing variation in output and in pointing position caused by instability of laser oscillation which is caused during machining by intermittent irradiation with high-output laser beam. <P>SOLUTION: The apparatus is equipped with: a focusing optical system that focuses a laser beam 17a emitted from a laser light source 11, a machining optical system 9 that guides the laser beam 17a to a workpiece 8 for irradiation with the laser beam, a shutter system 13 arranged between the focusing optical system and the machining optical system 9 and capable of shielding by reflecting the laser beam 17a. The shutter system 13 includes a reflection mirror 14 that can project onto the optical path of the focusing optical system and to the proximity of the focus point A of the laser beam 17a, wherein the reflection mirror 14, when projected, causes the laser beam 17a to diverge by reflecting (deflecting) it to outside the optical axis of the focusing optical system and the machining optical system 9. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an apparatus for performing high-precision and high-efficiency processing by irradiating a workpiece with laser light, and relates to a laser apparatus used for cutting, drilling, surface modification, welding, and the like of various materials, for example.

  In recent years, processing using laser light has been used for various applications in various industrial fields such as cutting of metal materials, fine drilling of electronic parts, welding of metal parts, and production of liquid crystal / semiconductor devices. Along with the spread of such laser processing, many techniques related to element parts for laser devices have been proposed for the purpose of improving the accuracy and efficiency of processing.

  In order to improve the accuracy of the laser processing, it is important to stabilize the laser output (laser pulse energy) and the pointing position (stabilize the fluctuation of the optical axis of the laser light source). In order to stabilize these, it is preferable to continuously oscillate without stopping the laser. However, in reality, there are very few examples of processing by scanning the laser like a single stroke while continuously oscillating the laser, and the laser is intermittently irradiated while repeatedly moving the object to be processed and the laser irradiation position. The method is often used.

  On the other hand, in order to increase the efficiency of laser processing, there is a method using a high-power laser light source. However, as laser output is increased, high laser resistance is required for optical elements such as lenses and mirrors and terminators for absorbing (damping) unnecessary reflected light and scattered light. It is coming. Of these, the terminator is a component that absorbs laser light, converts it into heat energy, and dissipates heat with a refrigerant. Therefore, the terminator is intended to improve durability with respect to a terminator for terminating a high-power laser. (See, for example, Patent Document 1 and Patent Document 2).

  In Patent Document 1 and Patent Document 2, a technique of disposing a concave lens immediately before the terminator is disclosed in order to improve the durability (lifetime) of the terminator. That is, there has been proposed a shutter configured such that reflected light is incident on the terminator after the laser light is diverged by the concave lens to reduce the energy density of the laser light.

  As a laser apparatus having a configuration similar to that of the laser apparatus according to the present invention, a technique in which light reflected by a shutter returns to a laser light source is also disclosed (see, for example, Patent Document 3). However, since the high-power laser light source may be damaged by the laser light reflected by the shutter, it is difficult to adopt the technique described in Patent Document 3 in a laser device using the high-power laser light source. is there.

As described above, the influence of the performance of the component parts for the laser device on the processing accuracy and the processing efficiency has been described. However, there are proposals for improving the processing accuracy and efficiency using a new optical system (for example, (See Non-Patent Document 1 and Non-Patent Document 2.) In Non-Patent Document 2, using a diffractive optical element, the position of the laser incident on the diffractive optical element, the diameter of the laser, the divergence angle, and the like are precisely adjusted to achieve uniform irradiation intensity. It is described that it can.
Japanese Unexamined Patent Publication No. 7-24591 Japanese Patent Laid-Open No. 11-342487 Japanese Utility Model Publication No. 61-61862 “SEI Technical Review”, Sumitomo Electric Industries, Ltd., September 2001, No. 159, p. 72-p. 77 “SEI Technical Review”, Sumitomo Electric Industries, Ltd., March 2005, No. 166, p. 13-p. 18

  The methods disclosed in Patent Document 1 and Patent Document 2 have a problem that at least one extra lens for diverging laser light is required. Also, when laser processing is performed by intermittently irradiating a high-power laser, the laser output (laser pulse energy) becomes unstable or the pointing position fluctuates as the time for stopping laser oscillation becomes longer. The problem occurs. The fluctuation of the laser output is a factor causing non-uniformity of machining, and the fluctuation of the pointing position is a factor of lowering the machining position accuracy.

  When the stability of the pointing position is poor, it becomes difficult for the laser beam to enter the center of the lens, and the characteristics of the laser beam irradiated to the object to be processed are deteriorated, which causes a reduction in processing accuracy. In particular, when using an aspheric lens or the diffractive optical element described in Non-Patent Document 1 and Non-Patent Document 2 for the purpose of uniformizing the laser intensity of the irradiated surface, in order to obtain a desired processing accuracy, Compared with a refractive lens, it is necessary to position the laser beam and the center of the lens with higher accuracy. That is, when using a diffractive optical element, it is necessary to stabilize the pointing position of the laser light source, so it is necessary to precisely adjust the laser diameter, the divergence angle, and the like.

  As described above, the main object of the present invention is to suppress output fluctuations and pointing position fluctuations caused by instability of laser oscillation, which occur when processing is performed by intermittently irradiating a high-power laser. .

  A laser apparatus according to the present invention includes a laser light source, a focusing optical system that focuses the laser light projected from the laser light source, a processing optical system that guides and irradiates the laser light to a processing target, and a focusing optical system. And a shutter system that is disposed between the processing optical system and can be cut off by reflecting the laser beam. The shutter system includes a reflecting mirror that can project on the optical path of the focusing optical system and near the focusing point of the laser beam. The reflecting mirror diverges the laser beam by reflecting (deflecting) the laser beam outside the optical axis of the focusing optical system and the processing optical system when it protrudes. Here, “near the laser beam focusing point” is the laser beam on the optical axis of the laser beam and immediately after the laser diameter of the laser beam focused by the focusing optical system is oscillated from the laser oscillation device. A range in the optical axis direction of the laser beam that is smaller than the diameter.

  In this case, since the laser diameter of the laser light blocked by the shutter system (reflected by the reflecting mirror) is smaller than the laser diameter of the laser light immediately after being oscillated from the laser oscillation device, the reflecting mirror itself is downsized. Thus, the operation of the reflecting mirror (opening and closing of the shutter system) can be performed at high speed. As a result, the time for suspending laser oscillation is shortened, and the laser oscillation state such as laser output and pointing position is stabilized.

  Preferably, the laser device further includes a terminator (damper) into which the laser beam reflected by the reflecting mirror is incident.

  Preferably, the reflecting mirror is configured to be able to project to the vicinity of the focal point of the laser beam by rotating, and the rotating shaft of the reflecting mirror is disposed parallel or perpendicular to the reflecting surface of the reflecting mirror. .

Preferably, the rotation axis of the reflecting mirror passes through the center of gravity of the reflecting mirror.
Preferably, the reflecting mirror is rotated by any one of a galvano scanner, a stepping motor, a servo motor, and a rotary solenoid.

  Preferably, a collimator lens system capable of adjusting a diameter (laser diameter) and a divergence angle of the laser light is provided on an optical path composed of a focusing optical system and a processing optical system.

Preferably, the processing optical system includes at least one diffractive optical element.
Preferably, the laser device further includes a stage on which the workpiece is placed, and a control device that controls the stage, the laser light source, and the shutter system, and the control device includes the stage, By changing the relative position of the laser beam with respect to the optical axis and opening and closing the shutter system, the workpiece is irradiated with the laser beam at a desired relative position and at a desired timing, and the workpiece is laser processed. The laser light source stops the laser beam irradiation during the opening / closing operation of the shutter system.

  As described above, the laser apparatus according to the present invention suppresses fluctuations in laser output and pointing position even when laser oscillation is intermittently performed. As a result, the characteristics of the laser beam irradiated onto the workpiece are stabilized, so that the machining accuracy by the laser beam is stabilized.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals, and when the names and functions of the parts are the same, detailed description of the parts will not be repeated.
[Embodiment 1]
<Laser device>
FIG. 1 is a schematic front view of a laser apparatus 1 according to Embodiment 1 of the present invention. As shown in FIG. 1, a laser apparatus 1 according to the present embodiment includes a laser light source 11, a focusing convex lens 12 (focusing optical system), a shutter system 13, a processing optical system 9, a stage 5, and a control device. 7. The processing optical system 9 is mainly composed of a mask 2, a mirror 3, and an imaging lens 4. The laser apparatus 1 according to the present embodiment irradiates a processing target 8 such as a wafer / glass substrate placed on the stage 5 with a laser beam 17a at a desired position at a desired timing. This is a laser processing apparatus that performs processing.

  The laser light source 11 is a laser light source that oscillates a laser beam 17a and processes the moving workpiece 8 (for example, a semiconductor thin film formed on a substrate) by the laser beam 17a. The laser beam 17a is an arbitrary laser beam selected according to the purpose of processing performed on the workpiece 8, and refers to, for example, an excimer laser, a YAG laser, a carbon dioxide gas laser, or the like.

  The workpiece 5 is placed on the stage 5 and continuously moves according to a command transmitted from the control device 7 described later.

  The mask 2 includes a light shielding part and a light transmitting part (not shown). The light shielding unit shields the irradiated laser beam 17a. The light transmitting part transmits the laser light 17a.

  The mirror 3 reflects the laser light 17a toward the workpiece 8. The arrangement location and quantity of the mirror 3 are not particularly limited, and the mirror 3 can be appropriately arranged based on the optical design and mechanism design of the laser device 1. In the present embodiment, the mirror 3 is disposed on the downstream side of the mask 2 and reflects the laser beam 17a transmitted through the mask 2 toward the workpiece 8.

  The imaging lens 4 forms an image of the laser beam 17a transmitted through the mask 2 on the surface of the workpiece 8 with a predetermined magnification.

  The control device 7 controls the moving speed and position of the stage 5, and also stores the timing and position at which the laser beam 17a is irradiated. The control device 7 controls the laser light source 11 to control the oscillation of the laser light 17a. The control device 7 recognizes the temperature and atmosphere inside the laser device 1 through various sensors, and the temperature and atmosphere. It is also a device that controls. The control device 7 is also a device that controls the operation of a shutter system 13 (23, 33) and a collimator lens system (41, 51), which will be described later.

  The stage 5 includes an unillustrated suction plate, X-axis linear scale, Y-axis linear scale, X linear motor, Y linear motor, X linear guide, and Y linear guide. The suction disk sucks the workpiece 8. The X-axis linear scale and the Y-axis linear scale measure the amount of movement of the stage 5. These linear scales are also a pulse generator 19 to be described later, which outputs pulses at regular intervals each time the stage 5 moves. The position of the stage 5 is detected based on the number of pulses (pulses output from the pulse generator 19) counted by a CPU (Central Processing Unit) 70 of the control device 7 described later. The X linear motor and the Y linear motor give a driving force to the stage 5. The X linear guide regulates the movement of the stage 5 in the X direction, and the Y linear guide regulates the movement of the stage 5 in the Y direction.

  FIG. 2 is a control block diagram relating to the control device 7 according to the present embodiment. As shown in FIG. 2, the control device 7 includes a monitor 62, a printer 64, a mouse 66, a keyboard 68, a CPU 70, a memory 72, an interface 74, a fixed disk 76, a CD-ROM (Compact Disk). It includes a Read Only Memory (Drive) device 78 and an FD (Flexible Disk) drive device 80.

The monitor 62 displays information. The printer 64 outputs information on paper. The mouse 66 receives information from the user when clicked or slid. The keyboard 68 receives the processing timing (irradiation time, etc.) and position of the laser beam 17a from the user by key input. The CPU 70 controls each block of the control device 7 and each device constituting the laser device 1 according to the present embodiment. The CPU 70 is also a device that performs various calculations. The memory 72 stores various information. The interface 74 converts information output from the CPU 70 into signals used by the stage 5, the laser light source 11, shutter systems 13, 23, 33 and collimator lens systems 41, 51 described later. The interface 74 is also a device that converts information of the CPU 70 into a signal that can be used by other circuits. The interface 74 is also a device that receives information input from each device of the laser device 1 according to the present embodiment and converts the information into information that can be used by the CPU 70. The fixed disk 76 stores a program executed by the CPU 70. A CD-ROM 52 is mounted on the CD-ROM driving device 78. An MO 50 is mounted on the MO drive device 80.
<Characteristics of laser device>
Hereinafter, the characteristics of the laser device 1 that performs laser processing on the workpiece 8 by irradiating the laser beam 17a intermittently from the laser light source 11 will be described with reference to FIGS. 3, 4, and 5. FIG.

  FIG. 3 is a plan view showing the movement of the relative position between the optical axis (laser irradiation position) of the laser beam 17a and the workpiece 8 when drilling the workpiece 8. FIG. As shown in FIG. 3, the laser apparatus 1 moves the relative position of the laser irradiation position with respect to the workpiece 8 from the machining start position p to the first hole machining position q. Specifically, the laser apparatus 1 moves the stage 5 in the direction opposite to the arrow in FIG. 3, stops the stage 5 when the stage 5 reaches the position q, and performs laser processing with the laser light 17a. When the laser processing is completed, the control device 7 temporarily stops the irradiation of the laser beam 17a. Thereafter, the control device 7 moves the relative position of the laser irradiation position with respect to the workpiece 8 to the second hole machining position r. When the laser irradiation position reaches the position r, the control device 7 stops the stage 5 and restarts the irradiation with the laser beam 17a. The laser device 1 sequentially performs laser processing on the workpiece 8 while repeating these series of operations.

  4 and 5 are timing charts showing changes in the position of the workpiece 8 relative to the laser irradiation position (laser irradiation position on the workpiece 8), laser irradiation timing (laser pulse), shutter operation, and laser pulse energy. The characteristics of the laser beam 17a oscillated from the laser light source 11 of the laser apparatus 1 are shown. Hereinafter, a phenomenon in which the characteristics of the laser light 17a oscillated from the laser light source 11 changes depending on the difference between the laser irradiation timing and the shutter operation will be described.

  First, in the laser processing method shown in FIG. 4, while the stage 5 is stopped (time: t2 → t3), the processing object 8 is irradiated with the laser beam 17a, and the processing position is changed (with respect to the laser irradiation position). While the position of the workpiece 8 is moving, the laser oscillation is stopped at time: t3 → t4). In this case, it is desirable that the shutter system 13 is always open.

  The laser pulse energy at the time of laser irradiation is generally high in the initial stage of laser pulse irradiation, decreases with time, and the energy change tends to be stable. Therefore, whether or not the processing object 8 is irradiated with the laser beam 17a is controlled not by turning the laser light source 11 ON / OFF (see FIG. 4) but by opening / closing the shutter system 13 (see FIG. 5). The method is preferred.

  The laser processing method shown in FIG. 5 differs from the laser processing method shown in FIG. 4 in that the laser light source 11 oscillates the laser light 17a almost continuously and the shutter system 13 is completely opened or completely closed. The laser oscillation is temporarily stopped only when the shutter system 13 is in a transition state (time during opening / closing operation of the shutter system 13, time: near t2 or near t3) until the state is reached.

  The laser pulse energy at the time of irradiation with the laser beam 17a is generally high at the initial stage of laser pulse radiation, and decreases with time, so that the energy change tends to be stable. The fluctuation width of the laser pulse energy in FIG. 5 is smaller than the fluctuation width of FIG. This is because the laser processing method shown in FIG. 5 has a shorter oscillation stop time of the laser light source 11 than the laser processing method shown in FIG. This is due to the characteristic of a general laser device that becomes “small”. Although not shown, the fluctuation of the pointing position shows the same tendency as the fluctuation of the laser pulse energy. When the laser beam 17a is continuously oscillated, the pointing position is stabilized with time.

  Also in the laser processing method shown in FIG. 5, the laser light source 11 temporarily stops laser oscillation during the transition state until the shutter system 13 is completely opened and closed (near t2 and t3 during the opening and closing operation of the shutter system 13). ing. This is to prevent the laser beam 17a from being irradiated to the reflecting mirror 14 during the opening / closing operation (transition state) of the shutter system 13 and being reflected to an unnecessary position.

  As described above, with reference to FIGS. 4 and 5, assuming that the laser light source 11 that oscillates a laser pulse is used in the laser apparatus 1, the position of the processing object 8 with respect to the laser irradiation position (laser irradiation position with respect to the processing object 8), Although the laser irradiation timing (laser pulse), shutter operation, and change in laser pulse energy have been described by way of example, the same result as described above can be obtained in the laser apparatus 1 using the laser light source 11 that continuously emits.

From the above, in order to stabilize the output of the laser light source 11 and the pointing position, it is preferable to continuously oscillate the laser beam 17a as much as possible, and as in the laser processing method shown in FIG. It is effective to temporarily stop the irradiation of the laser light 17a from the laser light source 11 only during the time required for opening and closing (during the opening and closing operation of the shutter system 13). In view of such characteristics of the laser device 1, in the present invention, the shutter system 13 is configured as follows.
<Shutter system>
FIG. 6 is a schematic front view showing the shutter system 13 and the like according to the present embodiment of the present invention. As shown in FIG. 6, the laser light 17 a oscillated from the laser light source 11 is refracted and focused by the focusing convex lens 12. The shutter system 13 is disposed downstream of the focusing convex lens 12 (focusing optical system), and includes a reflecting mirror 14 and a damper 16 (terminator). More specifically, the reflecting mirror 14 is on the optical axis of the laser beam 17a, and is located immediately after the focusing point A of the laser beam 17a by the focusing optical system (for example, the focusing convex lens 12) (position immediately downstream). It is arranged so that it can protrude.

  Specifically, the reflecting mirror 14 is rotatably supported in the shutter system 13 by a rotating shaft 15 that is rotatably provided in the shutter system 13. Then, the reflecting mirror 14 is rotated by the rotating shaft 15 so as to protrude on the optical axis of the laser beam 17a or to be out of the optical axis. That is, when the reflecting mirror 14 is in the dotted line position (shutter open state) shown in FIG. 6, the laser light 17a oscillated from the laser light source 11 is processed by the processing optical system 9, the mask 2, the mirror 3 and the image forming described later. After passing through the lens 4, the workpiece 8 is irradiated.

  On the other hand, when the reflecting mirror 14 is in the solid line position (shutter closed state) shown in FIG. 1, that is, when the laser beam 17 a is blocked, the laser beam 17 b (reflected beam) reflected by the reflecting mirror 14 is inside the damper 16. It is comprised so that it may inject into.

  As described above with reference to FIG. 5, the rotation of the rotation shaft 15 and the reflecting mirror 14 is performed in accordance with the oscillation timing of the laser light 17 a from the laser light source 11. The laser beam 17a is controlled based on the relative position with respect to the optical axis. Specifically, a pulse generator 19 for generating operation pulses (triggers) for the laser light source 11 and the shutter system 13 is provided on the stage 5, the control device 7, and other control panels. Then, as shown in FIG. 6, the pulse output from the pulse generator 19 is transmitted to the reflecting mirror driver circuit 20, and a driving signal is transmitted from the reflecting mirror driver circuit 20 to a motor (not shown), The rotating shaft 15 is rotated by the motor or the like.

  As shown in FIG. 6, when the intensity distribution 18 of the laser beam 17a oscillated from the laser light source 11 is a Gaussian distribution, an intensity peak appears at the center position of the laser beam 17a. The laser beam 17a has a higher energy density as its laser diameter (hereinafter referred to as laser diameter) is smaller. Therefore, when the high-power laser light source 11 is used, the damper 16 for the incidence of the laser beam 17b is damaged. There was a problem in durability, such as easy to do.

  For this reason, as described above, Patent Document 1 and Patent Document 2 propose a technique in which the laser diameter is enlarged and laser light having a small energy density is incident on the damper 16. However, the methods described in Patent Document 1 and Patent Document 2 require an extra lens for expanding the laser diameter in the laser device. Further, it does not consider the opening / closing of the high-speed shutter system 13 (rotation of the reflecting mirror 14) that is the subject of the present embodiment.

  As shown in FIG. 6, in the present embodiment, the reflecting surface (deflecting surface) of the reflecting mirror 14 (deflector) can protrude (arrange) immediately after the focusing point A of the laser light 17a. The laser diameter of the laser light 17 b after being reflected by the reflecting mirror 14 expands as the distance from the reflecting mirror 14 increases. Accordingly, unlike the methods described in Patent Document 1 and Patent Document 2, it is not necessary to dispose a concave lens or the like immediately before the damper 16, and the installation position of the damper 16 (the vertical installation position in FIG. 6) is set in advance. By simply adjusting, the energy density of the laser beam 17b (reflected light) incident on the damper 16 can be reduced according to the irradiation area of the damper 16. However, in the present embodiment, since the reflecting mirror 14 is disposed in the vicinity of the focal point A of the laser beam 17a by the focusing convex lens 12, the laser beam 17a having a high power density or energy density is formed on the reflecting surface of the reflecting mirror 14. Is irradiated. In consideration of the laser resistance (damage threshold) of the reflecting mirror 14, it is preferable that the installation position of the reflecting mirror 14 (horizontal installation position in FIG. 6) is determined.

More specifically, for example, the damage threshold of the reflecting mirror 14 is T _d (W / cm ² ), the radius of the laser light 17a at the position X is r _x (cm), and the peak power of the laser light source 11 is P ( W) and the case where the beam profile of the laser beam 17a has a Gaussian distribution (normal distribution) will be described. In this case, since it is necessary to satisfy T _d > 2P / πr _x ² , the reflecting mirror 14 needs to be arranged so as to protrude within a range satisfying r _x > (2P / πT _d ) ^1/2. There is. That is, the reflecting mirror 14 is disposed so as to protrude as close as possible to the focusing point A of the laser beam 17a by the focusing convex lens 12 within a range satisfying r _x > (2P / πT _d ) ^1/2. Is preferred. In other words, it is preferable that the arrangement position of the reflecting mirror 14 is adjusted so as to protrude to a position satisfying the above expression.

In the laser light source that oscillates with a laser pulse, the damage threshold of the reflecting mirror 14 is T _d2 (J / cm ² ), the laser beam radius at the position X is r _x (cm), and the laser energy per pulse ( When the pulse energy is E (J / Pulse) and the beam profile of the laser beam 17a is a Gaussian distribution, the following occurs. In this case, since it is necessary to satisfy T _d > 2P / πr _x ² , the reflecting mirror 14 is disposed so as to protrude within a range satisfying r _x > (2P / πT _d ) ^1/2. There is a need. That is, the reflecting mirror 14 is disposed so as to protrude as close as possible to the focal point A of the laser beam 17a by the converging convex lens 12 within a range satisfying r _x > (2P / πT _d ) ^1/2. Is preferred. In other words, it is preferable that the arrangement position of the reflecting mirror 14 is adjusted so as to protrude to a position satisfying the above expression.

  The reflecting mirror 14 is configured so as to be rotatable around the rotation shaft 15. However, in order to suddenly stop at a predetermined position after rotating at a high speed, the rotational inertia force of the reflecting mirror 14 is made as small as possible. There is a need. Here, in order to reduce the rotational inertial force, 1) make the reflecting mirror 14 itself smaller, and 2) make the rotating shaft 15 and the reflecting surface of the reflecting mirror 14 parallel or perpendicular (described in the third embodiment). 3) Arrangement of the rotating shaft 15 so that the rotating shaft 15 passes through the center of gravity of the reflecting mirror 14 (described in the second embodiment), etc. It is important to make the structure that does not act as much as possible.

  In Embodiment 1 shown in FIG. 6, since the reflecting mirror 14 is installed at a position where the laser diameter of the laser beam 17a is small, that is, immediately after the focusing point A of the focusing convex lens 12, the laser beam 17a blocked by the reflecting mirror 14 is shown. The laser diameter is small. In other words, the laser apparatus 1 according to the present embodiment is configured to block the laser light 17a having a small laser diameter by the shutter system 13, and thus the small reflecting mirror 14 can be used for the shutter system 13. The rotating shaft 15 that supports the reflecting mirror 14 is disposed so as to be parallel to the reflecting surface of the reflecting mirror 14. Thereby, the rotational inertia force of the reflecting mirror 14 can be reduced, and the reflecting mirror 14 can be rotated at high speed.

  The motor or the like used for rotating the rotating shaft 15 of the reflecting mirror 14 is a galvano scanner, a stepping motor, and a servo motor that can rotate at high speed and has excellent controllability of the rotation angle. , And a rotary solenoid are preferably used.

  Thus, a shutter system is adopted by adopting a driving method capable of high-speed rotation and a configuration that reduces the rotational inertia of the reflecting mirror 14 (a configuration that can be rapidly stopped at a predetermined position after high-speed rotation). Thus, the opening / closing operation 13 (rotation of the reflecting mirror 14) can be performed at high speed, and the laser oscillation pause time can be shortened. As a result, stabilization of the laser output and the pointing position can be realized.

[Embodiment 2]
FIG. 7 is a front view showing the shutter system 23 according to the second embodiment of the present invention, and is another example relating only to the shutter system 13 portion of the laser apparatus 1 according to the first embodiment shown in FIGS. This embodiment is shown. That is, in the following, the configuration of the shutter system 23 according to the second embodiment will be mainly described with reference to FIG. 7, and the functions and configurations of parts not described in FIG. 7 are related to the first embodiment. It is the same as the part.

  As shown in FIG. 7, the shutter system 23 of the laser apparatus 1 according to the present embodiment includes a reflecting mirror 14 and a damper 16. The reflecting mirror 14 is disposed immediately before the focusing point A of the laser beam 17 a by the focusing convex lens 12 and is configured to be rotatable around the rotating shaft 15. The rotating shaft 15 in the present embodiment is fixed to the reflecting mirror 14 in parallel with the reflecting surface of the reflecting mirror 14, passes through the reflecting mirror 14 through the center of gravity of the reflecting mirror 14, and The configuration is such that the eccentric load due to rotation does not act as much as possible.

  Then, the reflecting mirror 14 and the rotating shaft 15 are moved to a position immediately before (just upstream) of the focusing point of the laser beam 17a (the focal point of the focusing convex lens 12), that is, on the downstream side of the focusing convex lens 12 and the laser beam 17a. On the axis, the reflecting surface of the reflecting mirror 14 is disposed so as to protrude.

  That is, unlike the methods described in Patent Document 1 and Patent Document 2, the laser beam incident on the damper 16 is adjusted by adjusting the vertical installation position of the damper 16 without arranging a concave lens or the like immediately before the damper 16. The energy density of 17b (reflected light) can be reduced. However, since the laser beam 17a having a high energy density is irradiated on the reflecting surface of the reflecting mirror 14, the installation position of the reflecting mirror 14 may be determined in consideration of the laser resistance (damage threshold) of the reflecting mirror 14. desirable.

  In the second embodiment shown in FIG. 7, as described above, the reflecting mirror 14 is installed at a position where the laser diameter of the laser light 17 a is small, that is, immediately before the focusing point A of the focusing convex lens 12. A reflecting mirror 14 having a small surface area can be installed. Further, in order to reduce the rotational inertia force of the reflecting mirror 14, the rotation shaft 15 is disposed in parallel with the reflecting surface of the reflecting mirror 14. Furthermore, in order to reduce the rotational inertia force of the reflecting mirror 14, the rotation shaft 15 is disposed so as to pass through the center of gravity of the reflecting mirror 14. For this reason, compared with the shutter system 13 of the first embodiment shown in FIG. 6 and the like, the rotational inertia force of the reflecting mirror 14 is further reduced, the rotating speed of the reflecting mirror 14 can be increased, and the laser light source 11 pause time is shortened.

Other configurations and operational effects are the same as those of the first embodiment, and by adopting a driving method capable of rotating the reflecting mirror 14 at a high speed, the shutter system 23 can be opened and closed at high speed. .
[Embodiment 3]
FIG. 8 is a front view showing the shutter system 33 according to the third embodiment of the present invention, and is another implementation relating to the shutter system 13 of the laser device 1 according to the first embodiment described in FIGS. 1 to 6. The form of is shown. That is, hereinafter, the configuration of the shutter system 33 according to the third embodiment will be mainly described with reference to FIG. 8, and the functions and configurations of the parts not described in FIG. 8 are related to the first embodiment. It is the same as the part.

  As shown in FIG. 8, the shutter system 33 of the laser apparatus 1 according to the present embodiment includes a reflecting mirror 14 and a damper 16. The reflecting mirror 14 is disposed immediately after the converging point A of the laser beam 17a (the focal point of the converging convex lens 12), and is configured to be rotatable around the rotating shaft 15.

  In the present embodiment, since the reflecting surface of the reflecting mirror 14 is arranged immediately after the focusing point A of the laser beam 17a by the focusing convex lens 12, unlike the methods described in Patent Document 1 and Patent Document 2, The energy density of the laser beam 17b (reflected light) incident on the damper 16 can be reduced by adjusting the distance of the damper 16 from the reflecting mirror 14 without arranging a concave lens immediately before (above) the damper 16. it can. However, as described above, the reflecting surface of the reflecting mirror 14 is irradiated with the laser beam 17a having a high energy density, and therefore the installation position of the reflecting mirror 14 is considered in consideration of the laser resistance (damage threshold) of the reflecting mirror 14. It is necessary to determine.

  As described above, also in the present embodiment, since the reflecting mirror 14 is installed at a position where the laser diameter of the laser beam 17a is small, that is, immediately after the focusing point A of the focusing convex lens 12, the shutter system 33 has a laser diameter (reflection surface). Can be used. The rotating shaft 15 of the reflecting mirror 14 is arranged perpendicular to the reflecting surface of the reflecting mirror 14, and the rotating shaft 15 of the reflecting mirror 14 passes through the center of gravity of the reflecting mirror 14. Therefore, the rotational inertia force of the reflecting mirror 14 is further reduced as compared with the shutter system 13 of the first embodiment shown in FIG.

  However, in the present embodiment, the shutter system 33 should be designed so that the rotation shaft 15 does not block the optical path of the laser beam 17a focused by the focusing convex lens 12. This is because if the rotating shaft 15 blocks the laser beam 17a, the laser beam 17a applied to the workpiece 8 may be non-uniform. Specifically, it is preferable that the rotating shaft 15 and the reflecting mirror 14 be arranged eccentrically on either the left or right side of the optical axis of the laser beam 17a. Other configurations and operational effects are the same as those of the first embodiment, and the opening / closing operation of the shutter system 33 (rotation of the reflecting mirror 14) is speeded up by a driving method capable of rotating the reflecting mirror 14 at high speed. Can do.

Then, the position of the reflecting mirror 14 is in the vicinity of the converging convex lens 12, that is, the focal point A or immediately before or after the converging point A, and the shutter systems 13, 23, 33 are opened and closed by turning the reflecting mirror 14. The operation and the arrangement position / position of the rotation shaft 15 are independent matters. In the above, a part of the combination examples are described as the embodiment, but the object of the present invention can be achieved by other combinations.
[Embodiment 4]
FIG. 9 is a front view showing the optical system of the laser apparatus 1 according to the fourth embodiment of the present invention, and the focusing convex lens 12 (focusing optical system) and the shutter system according to the first embodiment in FIGS. 13 and another embodiment of the portion related to the processing optical system 9 are described.

  When laser processing is performed on the workpiece 8, it is necessary to further stabilize the pointing position of the laser light source 11. Therefore, in order to precisely adjust the laser diameter, divergence angle, and the like of the laser light 17a, it is preferable to install a so-called zooming collimator or the like between the laser light source 11 and a diffractive optical element 46 described later. In other words, the collimating lens system capable of adjusting the laser diameter, the divergence angle, and the like is disposed on the optical path of the laser beam 17a composed of the focusing optical system (focusing convex lens 12) and the processing optical system 9. Therefore, the uniformity of the irradiation intensity of the laser beam 17a with respect to 8 is achieved.

  The zooming collimator refers to a lens group configured such that the laser diameter and divergence angle of the collimator emission laser can be finely adjusted, and corresponds to a subordinate concept of the collimator lens system. In the present embodiment, a “zooming collimator” is used to adjust the laser diameter and the divergence angle more precisely, but other collimator lens systems capable of adjusting the laser diameter and the divergence angle on the optical path are used. The structure to arrange | position may be sufficient.

  As shown in FIG. 9, the laser apparatus 1 according to the present embodiment includes a laser light source 11, a focusing optical system (focusing convex lens 12), a shutter system 13, and a processing optical system 49. The shutter system 13 (23, 33) described in the first to third embodiments is employed as the shutter system. The arrangement positions of the shutter system 13 itself and the components constituting the shutter system 13 are the same as those in the first to third embodiments. In the laser device 1 of the present embodiment, a collimator lens system 41 is provided across the focusing optical system and the processing optical system 49. However, the focusing optical system upstream of the shutter system 13 may include the collimator lens system 41, or the downstream processing optical system 49 may include the collimator lens system 41. However, in any case, the reflecting mirror 14 of the shutter system 13 is disposed in the vicinity of the focusing point A of the laser light 17a by the focusing optical system (the focusing convex lens 12).

  In the present embodiment, as shown in FIG. 9, the converging convex lens 12 and the three lenses 42, 43, and 44 are disposed on the optical path composed of the converging optical system (the converging convex lens 12) and the processing optical system 49. A zooming collimator (collimator lens system 41) composed of: Specifically, the collimator lens system 41 includes a convex lens (hereinafter referred to as a first lens 42), a concave lens (hereinafter referred to as a second lens 43), and a convex lens (hereinafter referred to as a third lens) in order from the converging convex lens 12 side. Lens 44)). Then, by moving the first lens 42 and the third lens 44 of the collimator lens system 41 in the left-right direction in FIG. 9, the laser diameter and the divergence angle of the laser light 17a emitted from the collimator lens system 41 are fine. Adjusted.

  As shown in FIG. 9, in the present embodiment, unlike the first embodiment shown in FIG. 1, the processing optical system 9 is provided with a collimator lens system 41, a diffractive optical element 46, and the like. The diffractive optical element 46 can, for example, convert the intensity distribution of the laser beam 17a from a Gaussian distribution to a top-flat uniform laser, or branch one laser beam into a plurality of laser beams. .

  In the case where the diffractive optical element 46 is used, the position of the laser beam 17a incident on the diffractive optical element 46, the laser diameter, the divergence angle, and the like are precisely adjusted to achieve uniform intensity on the laser irradiation surface. Is done. However, as described in FIGS. 9 and 10 of Non-Patent Document 2, when the laser diameter varies by 10% (φ2 ± 0.2 mm) from the design value, the intensity of the irradiated surface changes to a concave or convex shape. To do. Further, when the position of the laser beam 17a incident on the diffractive optical element 46 is shifted by 12.5% (± 25 μm) of the laser diameter, the energy intensity profile of the irradiated surface shows an inclined shape.

As described above, when the diffractive optical element 46 is used, it is necessary to stabilize the pointing position of the laser light source 11 so that a laser shift or the like does not occur, and the laser light 17a irradiated to the workpiece 8 is used. In order to obtain a designed laser diameter, it is preferable that a collimator lens system 41 capable of adjusting the laser diameter and the divergence angle is disposed between the laser light source 11 and the diffractive optical element 46.
[Embodiment 5]
FIG. 10 is a front view showing the optical system of the laser apparatus 1 according to Embodiment 5 of the present invention. As shown in FIG. 10, the optical system of the laser device 1 according to the fifth embodiment is different from that of the fourth embodiment shown in FIG. 9 only in the configuration of the collimator lens system 51. The parts of are the same. That is, in the present embodiment, the first lens 52 and the second lens 53 of the collimator lens system 51 move in the left-right direction in FIG. The divergence angle is adjusted.

  As described above, in the fourth and fifth embodiments, each of the processing optical systems 49 and 59 includes a part of the collimator lens systems 41 and 51, the processing lenses 45 and 55, and the diffractive optical elements 46 and 46. It is out. Similarly to the first embodiment, the mask 2, the mirror 3, and the imaging lens 4 are disposed between the diffractive optical element 46 and the workpiece 8 in the laser device 1.

  In addition, the shutter systems 13, 23, and 33 described in the first to fifth embodiments are configured such that the shutter systems 13, 23, and 33 are opened and closed when the reflecting mirror 14 is rotated. For example, the shutter system 13, 23, 33 may be opened and closed by sliding. Also in this case, the area of the reflecting mirror 14 is reduced, so that the speed at which the reflecting mirror 14 slides can be increased.

  In the embodiment, the damper 16 is disposed in the shutter system 13 and the shutter system 13 includes the damper 16. However, the present invention is not limited to the configuration in which the damper 16 is included in the shutter system 13. The damper 16 may be provided in the laser device 1. In addition, as shown in FIGS. 6 to 10, in the above-described embodiment, the damper 16 is a so-called cone-type (conical) damper, but other types of dampers can be used.

  As described above, the laser apparatus 1 according to the embodiment includes the laser light source 11, the focusing optical system (focusing convex lens 12) that focuses the laser light 17a projected from the laser light source 11, and the laser. A processing optical system 9 that guides and irradiates the light 17a to the processing object 8, and a shutter system that is disposed between the focusing optical system and the processing optical system 9 and can be blocked by reflecting the laser light 17a. 13. The shutter system 13 includes a reflecting mirror 14 that can project on the optical path of the focusing optical system and near the focusing point A of the laser beam 17a. When the reflecting mirror 14 protrudes, the laser beam 17a is reflected (deflected) out of the optical axis of the focusing optical system and the processing optical system 9 to diverge.

  Here, the laser light source 11 oscillates the laser light 17a irradiated to the workpiece 8. The focusing optical system is disposed upstream of the laser path from which the laser light 17 a oscillated from the laser light source 11 reaches the workpiece 8, and focuses the laser light 17 a oscillated from the laser light source 11. The processing optical system 9 is arranged in the downstream part of the laser path from which the laser light 17a oscillated from the laser light source 11 reaches the workpiece 8, adjusts the laser diameter of the focused laser light 17a, and A lens system (mirror 3, imaging lens 4, etc.) for irradiating the workpiece 17 with the light 17 a is provided. The reflecting mirror 14 of the shutter system 13 is disposed between the focusing optical system and the processing optical system 9 on the optical path of the laser path from which the laser light 17 a oscillated from the laser light source 11 reaches the workpiece 8. The focused laser beam 17a is arranged at a position where the laser diameter is small. The “near the focal point of the laser beam” refers to a range in which the laser diameter of the laser beam 17a focused by the focusing optical system is smaller than the laser diameter of the laser beam 17a immediately after being oscillated from the laser light source 11. .

  In this case, since the laser diameter of the laser beam 17a when blocked by the shutter system 13 (reflected by the reflecting mirror 14) is small, the reflecting mirror 14 can be reduced in size and the reflecting mirror 14 is rotated. (Opening / closing operation of the shutter system 13) can be performed at high speed. As a result, the time for suspending laser oscillation is shortened, and the laser oscillation state such as laser output and pointing is stabilized. As a result, even when laser oscillation is intermittently performed, fluctuations in laser output and fluctuations in pointing position are suppressed. That is, since the characteristics of the laser beam 17a applied to the workpiece 8 are stabilized, the processing accuracy by the laser beam 17a is stabilized.

  The laser device 1 according to the embodiment includes a stage 5 on which a workpiece 8 is placed, and a control device 7 that controls the stage 5, the laser light source 11, the shutter system 13, and the like. Further prepare. The control device 7 changes the relative position between the stage 5 (processing object 8) and the optical axis of the laser light 17a, and opens and closes the shutter system 13 to perform the processing at a desired relative position and a desired timing. The object 8 is irradiated with a laser beam 17a, and the workpiece 8 is subjected to laser processing. During the opening / closing operation of the shutter system 13, the irradiation of the laser beam 17a by the laser light source 11 is stopped. . In this case, the laser apparatus 1 irradiates the laser beam 17a at a desired timing to a desired position of the workpiece 8 that is determined in advance by a user or the like while relatively moving the optical axis of the laser beam 17a and the workpiece 8. Thus, it is possible to perform laser processing on the workpiece 8. Since the irradiation of the laser light 17a from the laser light source 11 is stopped only during the opening / closing operation of the shutter system 13, the pause time of the laser light source 11 is shortened and the characteristics of the laser light 17a are stabilized.

  The laser device 1 further includes a terminator (damper 16) on which the laser light 17b (reflected light) reflected by the reflecting mirror 14 enters. The terminator is disposed outside the laser path where the laser beam 17a oscillated from the laser light source 11 reaches the workpiece 8, and converts the energy of the incident reflected light (laser beam 17b) into thermal energy. To dissipate heat. In this case, since the laser diameter of the laser light 17b is expanded even after being reflected by the reflecting mirror 14, the energy density of the laser light 17b incident on the terminator is reduced. That is, even when a high-power laser light source 11 is used in the laser device 1, the life of the terminator is extended without installing an extra optical system, so that the efficiency of laser processing is improved. Can do. Since the durability of the terminator is improved, the laser device 1 can be used safely.

  The reflecting mirror 14 is configured to be able to project to the vicinity of the focusing point A of the laser beam by rotating, and the rotating shaft 15 of the reflecting mirror 14 is configured to reflect the reflecting surface (reflecting surface) of the reflecting mirror 14. ) In parallel or perpendicular to In this case, since the rotational inertia force of the reflecting mirror 14 becomes small, the opening / closing operation of the shutter system 13 can be speeded up. As a result, it is possible to shorten the time for which laser oscillation is temporarily stopped during the opening / closing operation of the shutter system 13, and the laser oscillation state is stabilized. Therefore, the characteristic of the laser beam 17a irradiated to the workpiece 8 can be further stabilized, and the processing accuracy can be further stabilized.

  The rotating shaft 15 of the reflecting mirror 14 passes through the center of gravity of the reflecting mirror 14. In this case, since the rotational inertia force of the reflecting mirror 14 can be further reduced, the opening / closing operation of the shutter system 13 can be further speeded up. Since the time during which laser oscillation is temporarily stopped during the opening / closing operation of the shutter system 13 can be further shortened, the laser oscillation state is stabilized. Therefore, the characteristic of the laser beam 17a irradiated to the workpiece 8 can be further stabilized, and the processing accuracy can be further stabilized.

  Then, the reflecting mirror 14 (the rotation shaft 15 thereof) is rotated by any one of a galvano scanner, a stepping motor, a servo motor, and a rotary solenoid. In this case, the reflecting mirror 14 can be rotated at a high speed by using a rotation driving body (such as a galvano scanner, a stepping motor, a servo motor, a rotary solenoid, etc.) that can rotate at a high speed and control the rotation angle with high accuracy. In addition, since the laser beam 17a is reliably and stably incident on the center of the terminator, even the laser apparatus 1 having the high-power laser light source 11 can perform stable damping.

  The laser apparatus 1 includes collimator lens systems 41 and 51 that can adjust the laser diameter and the divergence angle of the laser light 17a on the optical path composed of the focusing optical system and the processing optical systems 49 and 59. The reflecting mirror 14 is disposed in the vicinity of the focal point A of the laser light 17a. Each of the collimator lens systems 41 and 51 is composed of a plurality of lenses, and the laser diameter and divergence angle of the laser light 17a irradiated on the workpiece 8 are adjusted by adjusting the relative distance between these lenses. Therefore, high-precision machining can be realized.

  The processing optical systems 49 and 59 include at least one diffractive optical element 46. In this case, since the fluctuation of the pointing position of the laser light source 11 can be suppressed by the shutter system 13 that can be opened and closed at high speed, the diffractive optical element 46 that requires highly accurate relative positioning with the laser light 17a functions effectively. When the diffractive optical element 46 is effectively used in the laser apparatus 1, higher accuracy and higher efficiency of laser processing can be achieved.

  The disclosed embodiments are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a schematic front view of the laser apparatus concerning Embodiment 1 of this invention. It is a control block diagram regarding the control apparatus which concerns on Embodiment 1 of this invention. It is a top view which shows the movement of the relative position with respect to the process target object of the optical axis of a laser beam. It is a chart which shows the energy fluctuation | variation in the case of stopping laser oscillation during the movement of a stage. 6 is a chart showing energy fluctuation when laser oscillation is stopped only during a shutter opening / closing operation. It is a front view which shows the shutter system etc. which concern on Embodiment 1 of this invention. It is a side view which shows the shutter system which concerns on Embodiment 2 of this invention. It is a side view which shows the shutter system which concerns on Embodiment 3 of this invention. It is a front view which shows the optical system of the laser apparatus concerning Embodiment 4 of this invention. It is a front view which shows the optical system of the laser apparatus concerning Embodiment 5 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Laser apparatus, 8 Processing target object, 9, 49, 59 Processing optical system, 11 Laser light source, 12 Focusing convex lens (focusing optical system), 13, 23, 33 Shutter system, 14 Reflecting mirror (deflector), 15 Reflecting mirror Rotation axis, 16 damper (terminator), 17a, 17b laser beam, 41, 51 collimator lens system.

Claims (8)

A laser light source;
A focusing optical system for focusing laser light projected from the laser light source;
A processing optical system for directing and irradiating the laser beam to a processing object;
A shutter system disposed between the focusing optical system and the processing optical system and capable of blocking by reflecting the laser light,
The shutter system includes a reflecting mirror capable of projecting on the optical path of the focusing optical system and near the focusing point of the laser beam,
The reflection mirror is a laser device that reflects the laser beam to the outside of the optical axis of the focusing optical system and the processing optical system when protruding.   The laser apparatus according to claim 1, further comprising a terminator on which the laser light reflected by the reflecting mirror is incident. The reflecting mirror is configured to be able to protrude to the vicinity of the focal point of the laser beam by rotating,
3. The laser device according to claim 1, wherein a rotation axis of the reflecting mirror is disposed in parallel or perpendicular to a reflecting surface of the reflecting mirror.   The laser apparatus according to claim 3, wherein a rotation axis of the reflecting mirror passes through a center of gravity of the reflecting mirror.   The laser device according to claim 3, wherein the reflecting mirror is rotated by any one of a galvano scanner, a stepping motor, a servo motor, and a rotary solenoid.   The laser according to any one of claims 1 to 5, further comprising a collimator lens system capable of adjusting a diameter and a divergence angle of the laser light on an optical path configured by the focusing optical system and the processing optical system. apparatus.   The laser apparatus according to claim 1, wherein the processing optical system includes at least one diffractive optical element. The laser device is
A stage on which the workpiece is placed;
A control device for controlling the stage, the laser light source, and the shutter system;
The controller is
Changing the relative position of the stage and the optical axis of the laser beam;
By opening and closing the shutter system, the workpiece is irradiated with laser light at a desired relative position and desired timing, and laser processing is performed on the workpiece.
The laser device according to any one of claims 1 to 7, wherein the laser light source stops the irradiation of the laser beam during the opening / closing operation of the shutter system.

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