JP2019134008A - Laser device - Google Patents

Abstract

To provide a laser device capable of maintaining a stable beam profile.SOLUTION: An optical component is arranged in a beam path through which a laser beam passes. A blower generates a flow of air in a space including the optical component.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a laser apparatus.

  A laser beam transmission path in which a non-absorbing gas is filled in a laser beam transmission path main body having airtightness is known (Patent Document 1). The transmission path main body disclosed in Patent Document 1 has a shape along the propagation path of the laser beam and has airtightness. A non-absorbing gas inlet is provided near the start point of the transmission line body, and an outlet is provided near the end point.

JP 59-206804 A

  In order to use a laser beam for drilling a printed wiring board or the like, generally, a beam profile adjusting mechanism such as a lens and an aperture is arranged in the path of the laser beam. It is difficult to arrange these beam profile adjusting mechanisms by adjusting the optical axis inside the highly airtight transmission line body. According to experiments by the inventors of the present application, it has been found that when the propagation path of the laser beam is an open space without airtightness, a stable beam profile may not be obtained.

  An object of the present invention is to provide a laser apparatus capable of maintaining a stable beam profile.

According to one aspect of the invention,
Optical components arranged in the beam path through which the laser beam passes;
There is provided a laser device having a blower for generating an air flow in a space including the optical component therein.

  Since it is not necessary to maintain airtightness when the space included in the optical component is in the atmospheric state, the optical axis of the optical component can be easily adjusted. Moreover, the beam profile can be stabilized in time by generating an atmospheric flow.

FIG. 1 is a schematic diagram of a laser apparatus according to an embodiment. 2A and 2B are a schematic front view and a schematic plan view of the laser device according to the embodiment shown in FIG. 1, respectively. FIG. 3A is a shading diagram and graph showing the measurement results of the beam profile at the position of the photodetector of the laser apparatus according to the embodiment shown in FIG. 1, and FIG. It is the shading figure and graph which show the measurement result of a profile. FIG. 4 is a perspective view of an optical chamber of a laser apparatus according to another embodiment.

A laser apparatus according to an embodiment will be described with reference to FIGS.
FIG. 1 is a schematic diagram of a laser apparatus according to an embodiment. The laser oscillator 10 outputs a laser beam. As the laser oscillator 10, a laser oscillator that outputs a laser beam in a wavelength region that is not substantially absorbed by the atmosphere, such as a carbon dioxide laser oscillator, can be used.

  Optical components such as a beam expander 11, bending mirrors 12, 14, 16, an aperture 13, and a branching optical system 15 are arranged in the beam path of the laser beam output from the laser oscillator 10. The beam expander 11 changes the beam diameter and divergence angle of the laser beam output from the laser oscillator 10. The laser beam that has passed through the beam expander 11 is reflected by the bending mirror 12 and enters the aperture 13. The aperture 13 shapes the beam cross section of the laser beam. The laser beam that has passed through the aperture 13 is reflected by the bending mirror 14 and enters the branching optical system 15. The beam path from the laser oscillator 10 to the branch optical system 15 is substantially parallel to the horizontal plane.

  The branching optical system 15 branches the incident laser beam into two beam paths. As the branching optical system 15, a half mirror, a polarization beam splitter, or the like can be used.

  A part of the laser beam incident on the bending mirror 12 passes through the bending mirror 12 and enters the photodetector 19. The photodetector 19 outputs an electrical signal corresponding to the light intensity of the incident laser beam. The detection result detected by the photodetector 19 is used, for example, for feedback to the laser oscillator 10 and confirmation of the normality of the operation of the laser oscillator 10.

  The laser beam branched by the branching optical system 15 and propagating through one beam path (downward beam path) enters the workpiece 20A via the beam scanner 17A and the lens 18A. The laser beam propagating through the other beam path (the beam path toward the horizontal direction) is reflected downward by the bending mirror 16 and then enters the workpiece 20B via the beam scanner 17B and the lens 18B. To do. The beam scanners 17A and 17B include, for example, a pair of galvanometer mirrors, and have a function of scanning a pulse laser beam in a two-dimensional direction. The lenses 18A and 18B focus the pulse laser beam on the surfaces of the workpieces 20A and 20B, respectively. Note that the aperture 13 may be configured to form an image on the surfaces of the workpieces 20A and 20B.

  The processing objects 20 </ b> A and 20 </ b> B are, for example, printed wiring boards, and are held on the holding surface of the stage 21. For example, drilling is performed by making a pulsed laser beam incident on a printed wiring board. The holding surface of the stage 21 is horizontal, for example. The stage 21 can move the workpieces 20A and 20B in two directions in the horizontal plane. As the stage 21, for example, an XY stage can be used.

  The blower 30 generates an air flow in a space including optical components such as the beam expander 11, bending mirrors 12, 14, 16, aperture 13, branching optical system 15, and photodetector 19. As the blower 30, for example, a fan can be used. Thereby, an air flow is generated in a space including the beam path and the optical component.

  2A and 2B are a schematic front view and a schematic plan view of the laser apparatus according to the present embodiment, respectively.

  An optical surface plate 25 and a stage 21 are supported on the base 26. Optical components such as a beam expander 11, bending mirrors 12, 14, 16, an aperture 13, a branching optical system 15, and a photodetector 19 are supported on the optical surface plate 25. Below the optical surface plate 25, beam scanners 17A and 17B and lenses 18A and 18B are supported. The blower 30 generates an air flow in a space where the optical components on the optical surface plate 25 are arranged.

  Next, the excellent effect obtained by adopting the configuration of the laser apparatus according to the above embodiment will be described.

  In the above embodiment, the optical components such as the beam expander 11, the bending mirrors 12, 14, 16, the aperture 13, the branching optical system 15, and the photodetector 19 are placed on the optical surface plate 25 (FIGS. 2A and 2B). Arranged in space. This space is open to the atmosphere and airtightness is not guaranteed. For this reason, compared with the structure which arrange | positions an optical component in a space with high airtightness, the optical axis adjustment of various optical components, etc. can be performed easily.

  Next, with reference to FIG. 3A and FIG. 3B, the excellent effect obtained by producing the flow of air | atmosphere is demonstrated.

  FIG. 3A is a shading diagram and a graph showing the measurement result of the beam profile at the position of the photodetector 19 of the laser apparatus according to the present embodiment. The graphs on the left and lower sides of the gray scale diagram show the beam profiles along vertical and horizontal straight lines passing through the center of the beam cross section, respectively. In this example, the beam profile shown in FIG. 3A was obtained stably in time.

  FIG. 3B is a shading diagram and a graph showing a beam profile measured in a state where the atmosphere in the space where the optical components are arranged is substantially stationary without generating an air flow. Between the beam profile shown on the left side of FIG. 3B and the beam profile shown on the right side, the beam profile varied with time.

  From the measurement results shown in FIGS. 3A and 3B, it can be seen that the beam profile can be stabilized by generating an air flow in the space where the optical component is arranged. According to various evaluation experiments by the inventors of the present application, it has been found that a sufficient effect of stabilizing the beam profile cannot be obtained at a wind speed of 0.2 m / s or less. Further, it has been found that the wind speed is preferably 0.5 m / s or more in order to obtain a sufficient effect of stabilizing the beam profile.

  Next, the reason why the beam profile can be stabilized by generating an air flow will be considered. The atmosphere on the beam path is slightly heated by the laser beam. At this time, if the atmosphere is stagnant, the temperature rise in the beam path becomes remarkable, and density fluctuation occurs in the atmosphere. Along with this, the refractive index of light also fluctuates. Since the beam profile is affected by the refractive index distribution over the entire beam path, it is considered that the beam profile becomes temporally and spatially unstable. If an atmospheric flow is generated in this embodiment, it is considered that the fluctuation of the atmosphere due to a local temperature rise in the beam path is eliminated and the temporal stability of the beam profile is enhanced.

  Next, a laser apparatus according to another embodiment will be described with reference to FIG. Hereinafter, description of the configuration common to the configuration of the laser apparatus according to the embodiment shown in FIGS. 1 to 2B will be omitted.

  FIG. 4 is a perspective view of the optical chamber of the laser apparatus according to this embodiment. A cover 27 covers a space in which optical components on the optical surface plate 25 are accommodated. The cover 27 includes, for example, a side wall that goes around a space in which the optical component is accommodated and a top plate that closes the upper side of the side wall in a plan view. A blower 30 is attached to the side wall of the cover 27. A filter is attached to the air intake port of the blower 30. An opening 31 is provided on the side wall at a position facing the side wall to which the blower 30 is attached.

  The blower 30 introduces external air into the optical chamber surrounded by the cover 27. The air introduced into the optical chamber flows through the optical chamber and flows out through the opening 31. As described above, the blower 30 has a function of ventilating the inside of the optical chamber surrounded by the cover 27.

  Next, the excellent effect obtained by adopting the configuration of the laser apparatus according to the embodiment shown in FIG. 4 will be described. Also in the embodiment shown in FIG. 4, the optical axis of the optical component can be easily adjusted by removing the cover 27 from the optical surface plate 25. Furthermore, it is possible to suppress particles from entering the optical chamber in which the optical components are arranged.

  Each of the above-described embodiments is an exemplification, and needless to say, partial replacement or combination of the configurations shown in the different embodiments is possible. About the same effect by the same composition of a plurality of examples, it does not refer to every example one by one. Furthermore, the present invention is not limited to the embodiments described above. It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

DESCRIPTION OF SYMBOLS 10 Laser oscillator 11 Beam expander 12 Bending mirror 13 Aperture 14 Bending mirror 15 Branching optical system 16 Bending mirror 17A, 17B Beam scanner 18A, 18B Lens 19 Photo detector 20A, 20B Work object 21 Stage 25 Optical surface plate 26 Base 27 Cover 30 Blower 31 Opening

Claims (4)

Optical components arranged in the beam path through which the laser beam passes;
And a blower for generating an air flow in a space including the optical component therein. A cover that covers a space in which the beam path and the optical component are disposed;
The laser device according to claim 1, wherein the blower generates an air flow in a space covered with the cover.   The laser device according to claim 2, wherein the blower ventilates a space covered with the cover.   4. The laser device according to claim 1, wherein the blower generates an air flow having a wind speed of 0.5 m / s or more in a space including the optical component therein. 5.