JP2016131997A - Laser cutting optical unit and laser cutter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser cutting optical unit and a laser cutter, which enable a user to cut curves in transparent material with a laser beam.SOLUTION: There is provided a laser cutting optical unit. An optical unit 10 for irradiating transparent material 5 with a laser beam 2 and processing the material includes: an optical element 41 for branching the laser beam into multiple branched laser beams; a focusing lens 42 where all the branched laser beams 21 having branched into multiple beams at the optical element are incident; a rotatable optical lens barrel 4 having the optical element and the focusing lens; and a rotary drive 44 for rotating the optical lens barrel around a central axis 40 of rotation along a direction where the laser beam is incident. The optical lens barrel is rotated around the central axis of rotation by the rotary drive, and the branched laser beams are focused on the respective spots 23 inside the transparent material, thus laser cutting is performed.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a laser cutting optical unit and a laser cutting device used for dividing a transparent material such as glass used for a display or the like.

  As a conventional laser cutting optical system, a laser beam emitted from an ultrashort pulse laser light source is divided into a plurality of parts by using a splitter and a mirror, and a condensing lens is arranged for each laser beam to simultaneously process a plurality of points. (For example, refer to Patent Document 1). FIG. 6 is a diagram showing a conventional laser cutting optical system described in Patent Document 1. In FIG.

  In FIG. 6, the laser beam 102 is divided into a plurality of divided beams 123 to 130 by a beam dividing means 171. In the condensing lens group 135, the plurality of divided beams 123 to 130 are separated along a planned cutting line, and condensing points 145 to 146 are arranged to form a plurality of cavities 183 to 190. .

  In addition, as a conventional laser cutting optical system, there is one in which a plurality of laser heads are provided with respective optical systems (see, for example, Patent Document 2). FIG. 7 is a diagram showing a configuration of a conventional laser cutting optical system described in Patent Document 2. In FIG.

  In FIG. 7, a plurality of laser heads can move independently, and the two laser heads 231 are indexed and fed from both ends of the wafer W toward the center, or from the center of the wafer W toward both ends. The two lines are simultaneously processed over the entire surface of the wafer W by being indexed and fed, or spaced apart by a predetermined line and indexed and fed in the same direction. Alternatively, the laser beam L is irradiated twice on the entire surface of the wafer W with a predetermined distance or a predetermined line delay.

Japanese Patent No. 5379384 JP 2004-111946 A

  However, in the conventional configuration, for the splitting and condensing of the laser beam, a splitter and a lens are used for each laser beam, and the laser beam usually has a diameter of several millimeters. The distance between them is easily estimated to be at least about 10 mm. For this reason, the condensing lens groups that are spaced apart along the planned cutting line can only be arranged with a straight line or a constant large radius of curvature, and can be cut into a free curve including a small radius of curvature. It has a problem that it cannot be done.

  The present invention solves the above-described conventional problems, and an object of the present invention is to provide a laser cutting optical unit and a laser cutting apparatus that can cut a transparent material while drawing a curve when cutting with a laser beam. And

In order to achieve the above object, a laser cutting optical unit according to one aspect of the present invention is an optical unit for performing processing by irradiating a transparent material with a laser beam.
An optical element for branching the laser beam into a plurality of branch laser beams;
A condensing lens on which all of the branched laser beams branched into the plurality by the optical element are incident;
A rotatable optical barrel having the optical element and the condenser lens;
A rotation driving device that rotates the optical barrel around a rotation center axis along a direction in which the laser beam is incident;
The optical barrel is rotated about the rotation center axis by the rotation driving device, and the branched laser beam is condensed on each spot inside the transparent material to perform laser cutting.

  As described above, according to the above aspect of the present invention, when the transparent material is cut, the optical element and the condenser lens can be rotated by the rotation driving device to control the branching direction of the laser beam. Therefore, the transparent material can be cut in a curved shape.

The longitudinal cross-sectional schematic diagram which shows the structure of the laser cutting apparatus containing the oblique irradiation type laser cutting optical unit in 1st Embodiment of this invention. Calculation schematic diagram of rotation angle allowable value at the time of curve processing in the first embodiment of the present invention The longitudinal cross-sectional schematic diagram which shows the structure of the laser cutting apparatus containing the vertical irradiation type laser cutting optical unit in the 1st modification of 1st Embodiment of this invention. The typical perspective view which shows the processing state at the time of the optical barrel rotation in the 1st modification of 1st Embodiment of this invention. The block diagram of the 0th-order light countermeasure optical unit at the time of multi-branching in 2nd Embodiment of this invention The figure which shows the example of the conventional laser cutting optical system described in patent document 1 The figure which shows the example of the conventional laser cutting optical system described in patent document 2

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a configuration diagram of a laser cutting device 11 including an oblique irradiation type laser cutting optical unit 10 according to the first embodiment of the present invention. In the following description, as an example of the transparent material to be processed, an upper transparent material 51 and a lower transparent material 52 of the display panel 5 are configured by overlapping two layers of transparent plates.

  As an example of each material of the upper transparent material 51 and the lower transparent material 52, glass can be used. More specifically, non-alkali glass used for display can be used as each material. The example of each shape of each transparent material 51 and 52 is flat form, and the example of each plate | board thickness is 200 micrometers. As each plate | board thickness of each transparent material 51 and 52 which can be used by this 1st Embodiment, you may enter into the range of 30-1000 micrometers as an example.

  The laser cutting device 11 includes at least a laser oscillator 1 and a laser cutting optical unit 10. In this laser cutting device 11, the laser beam 2 from the laser oscillator 1 is bent by the mirror 3 and incident on the laser cutting optical unit 10, and the laser cutting optical unit 10 irradiates the transparent material 51, 52 with the laser beam 2. Laser cutting is performed.

  The laser cutting optical unit 10 includes a rotating lens barrel 4 as an example of an optical lens barrel and a rotation driving device 44.

  The rotating barrel 4 includes an optical element 41 and a condenser lens 42.

  The optical element 41 is constituted by a diffractive optical element as an example, and branches the laser beam 2 into a plurality of branched laser beams 21.

  The condensing lens 42 receives all of the branched laser beam 21 branched into a plurality by the optical element 41 and is focused on the respective spots 23 inside the transparent materials 51 and 52 to perform laser cutting.

  The rotation driving device 44 is configured by a motor or the like as an example, and rotates the rotating barrel 4 in one direction or forward and backward directions with the direction in which the laser beam 2 is incident as the rotation center axis 40. By the rotation of the rotating barrel 4, the optical element 41 and the condenser lens 42 are integrally rotated around the rotation center axis 40.

  In FIG. 1, a laser oscillator 1 is an oscillator that oscillates an ultrashort pulse laser beam 2. For example, a laser beam 2 having a pulse width of 25 picoseconds is placed inside transparent materials 51 and 52 on a stage 8. By collecting the light, it is possible to cause absorption due to a non-linear effect and generate a processing mark 6. The laser beam 2 emitted from the laser oscillator 1 is guided to the rotating lens barrel 4 through one or a plurality of mirrors 3.

  The rotating barrel 4 and the display panel 5 move relatively in the direction of the arrow 20. The display panel 5 is mounted on the stage 8. The stage 8 holds the transparent materials 51 and 52 of the display panel 5 on its upper surface, and can be moved in the X and Y directions orthogonal to each other by driving a stage driving device 8x composed of a motor, a ball screw, a nut member, and the like. It is said. However, the present invention is not limited to such a configuration, and the stage 8 may be a fixing member that does not move at all and that holds the transparent materials 51 and 52 in a non-movable manner. In such a case, the laser cutting optical unit 10 is configured to move with respect to the stage 8 by various known driving devices such as a motor.

  The rotating barrel 4 is located at a position decentered with respect to the rotation center axis 40 via the mirror 3 and a diffractive optical element 41 (hereinafter referred to as “DOE” for short) and a condenser lens. 42 is fixed. The optical axis of the DOE 41 and the optical axis of the condenser lens 42 coincide with each other. The optical axis of the DOE 41 and the optical axis of the condenser lens 42 are arranged so as to intersect with the rotation center axis 40 at a predetermined angle. As described above, when the DOE 41 is used, the energy ratio of each branched laser beam 21 can be changed. For example, when a transparent material is formed of a plurality of layers of glass like the display 5, processing is performed. By adjusting the energy ratio according to the depth to be processed, it is possible to reduce the difference in the machining state depending on the depth.

  The laser beam 2 is incident on the rotary barrel 4 along the rotation center axis 40 at the center of the upper end of the rotary barrel 4. The incident laser beam 2 is bent by the two mirrors 3 inside the rotating lens barrel 4 and then passes through the DOE 41 to become a plurality of, for example, eight branched laser beams 21. . Thereafter, the branched laser beam 21 branched by the DOE 41 is condensed by the condensing lens 42 on the respective spots 23 inside the transparent materials 51 and 52. At this time, as an example, a branch group width 702 in FIG. 2 to be described later was 0.2 mm.

  Here, the optical axis of the laser beam 2 incident on the center of the upper end of the rotary lens barrel 4 is arranged so as to be coaxial with the rotation center axis 40. Further, the center of the eight branched laser beam beams 21 emitted from the rotating lens barrel 4, that is, the center of gravity of the eight focused spots 23 is arranged so that the rotation center axis 40 passes through. Yes.

  The plurality of spots 23 are arranged such that the optical axes of the DOE 41 and the condenser lens 42 are inclined with respect to the laser beam incident surfaces 5a of the transparent materials 51 and 52 of the display panel 5 as an example of a processing target. With this configuration, the condensing points 23 of the branched laser beam 21 are dispersed in a stepwise manner in the depth direction of the display panel 5 that is an example of the processing target so that the depth changes stepwise. The tube 4 and the display panel 5 are relatively moved in the direction of the arrow 20 and processed in advance from the branch spot (the lower end spot in FIG. 1) 23 far from the rotating lens barrel 4 (the condensing lens 42). The upper transparent material 51 and the lower transparent material 52 can be processed at the same time by sequentially processing the branch spot (upper spot with respect to the processed spot in FIG. 1) 23 close to the rotary lens barrel 4. . That is, when the transparent materials 51 and 52 are viewed from the direction on which the branched laser beam 21 is irradiated, the branched laser beams 21 are arranged in a straight line, and the transparent materials 51 and 52 from the laser beam incident surface 5a. When condensing at different depths, the depth of the condensing point (condensing spot) 23 that is the forefront in the traveling direction of the cutting line is the deepest, and the condensing point (concentrating point) that is the last in the traveling direction of the cutting line. The depth of the (light spot) 23 is close to the outermost surface of the transparent material 51, 52 on the laser beam incident side, and the processing traces by the foremost and rearmost condensing points (condensed spots) 23 reach the surface. The other condensing points (condensing spots) 23 are processed by gradually changing the depth so as to smoothly connect the two condensing points, so that the upper transparent material 51 and the lower condensing point 23 Process and cut transparent material 52 simultaneously It is possible. For this reason, it is possible to cut the display panel 5 by one scanning of the laser cutting optical unit 10 (relative one movement of the rotating barrel 4 and the display panel 5 in the direction of the arrow 20). It has become.

  In the first embodiment of the present invention, the pulse width of the ultrashort pulse oscillator 1 is set to 25 picoseconds as an example, but may be set to be larger than 0 nanoseconds and not longer than 20 nanoseconds.

Further, as an example, the number of branches of the branched laser beam 21 is eight, but it may be any number of two or more. Further, the width in which the spot diameter is dispersed may be in the range of 0.01 to 2 mm. good.

  FIG. 2 is a schematic diagram of calculation of an allowable rotation angle value during curve processing in the laser cutting optical unit 10 according to the first embodiment of the present invention. FIG. 2A is a schematic view of the spot distribution at the processing point as viewed from the incident side of the branched laser beam 21 (FIG. 1). At this time, the depth of the processing marks 61 to 68 changes stepwise in the depth direction on the paper surface when the schematic diagram is viewed. In the first embodiment of the present invention, as an example, the spot processing width 701 is about 5 μm, and the spot group branching width 702 is about 200 μm.

  FIG. 2B shows a spot distribution 71 initially processed in the spot distribution at the processing point of FIG. 2A, and a spot distribution 72 after the optical barrel 4 moves while rotating. Is shown. At this time, the maximum allowable angle 703 allowed when performing the curve processing was calculated based on the following concept. The spot distribution 72 after the optical barrel 4 is moved while rotating is the optical mirror when the spot distribution moves from the initially processed spot distribution 71 by a distance half the width 702 where the spot is branched. If the machining trace 68 in the spot distribution 72 after the cylinder 4 moves while rotating is within an angle in contact with the spot machining width 701 in the initially machined spot distribution 71, the curve machining becomes possible. Considering this, the maximum allowable angle 703 at this time was calculated as follows.

Maximum permissible angle = tan ⁻¹ (Spot processing width 701 / (Spot group branching width 702/2))
= Tan ^-1 (5 / (200/2))
= 2.86deg
= 49.96 mrad
The minimum radius of curvature obtained from the value of the maximum allowable angle is 2 mm.

  Similarly, when calculating the allowable angle of the conventional patent document 1, when the spot processing width 701 is estimated to be 5 μm and the branched width 702 is estimated to be 70 mm, the maximum allowable angle is as follows. .

Maximum allowable angle = tan ^-1 (5 / (70000/2))
= 0.008deg
= 0.14 mrad
When the minimum radius of curvature is obtained from the value of the maximum allowable angle, it is 245 m (= 245000 mm). In other words, it can be seen that the conventional example can only process a substantially straight line.

  Therefore, it has been found that in the example of the first embodiment of the present invention, curved machining with a minimum radius of 2 mm is possible.

  Next, FIG. 3 is a configuration diagram of a laser cutting device 11B including a vertical irradiation type laser cutting optical unit 10B according to a first modification of the first embodiment. The laser cutting device 11B includes at least a laser oscillator 1 and a laser cutting optical unit 10B.

  In the rotating barrel 4 of the laser cutting optical unit 10B of FIG. 3, the mirror 3 is not provided, and the optical axis of the DOE 41 and the optical axis of the condensing lens 42 are arranged on the rotation center axis 40, respectively. A wedge plate 43 that disperses the branched laser beam 21 in the direction along the rotation center axis 40 is disposed below the lens 42.

  In FIG. 3, the description of the same configuration as in FIG. 1 is omitted.

  Each condensing spot 23 of the branched laser beam 21 branched into a plurality by the DOE 41 is dispersed in the depth direction of the display panel 5 as an example of a processing target by a wedge plate 43 installed below the condensing lens 42. The upper transparent material 51 and the lower transparent material 52 can be processed simultaneously. For this reason, it is possible to cut the display panel 5 by one scan of the laser cutting optical unit 10B (relative one movement of the rotating barrel 4 and the display panel 5 in the direction of the arrow 20). It has become.

  Further, in the optical unit 10B of FIG. 3, the optical components (DOE 41, condenser lens 42, and wedge plate 43) arranged inside the rotary lens barrel 4 are linearly arranged on the rotation center axis 40. Due to such an arrangement, the size of the rotary lens barrel 4 along the rotation center axis 40 can be reduced, and the moment of inertia during rotation of the rotary lens barrel 4 composed of the DOE 41 and the condenser lens 42 is reduced. The merit that the rotary lens barrel 4 can be rotated at high speed is obtained. Thus, cutting can be performed at a high speed even when curve processing is performed.

  In this modification, an example in which the wedge plate 43 is used to disperse the condensed spot 23 of the branched laser beam 21 in the depth direction of the display panel 5 is described. However, it is also possible to perform spot dispersion in the depth direction by using a design in which a Fresnel lens image is superimposed when designing the DOE 41 without using the wedge plate 43.

  Further, the distance in the depth direction of the focused spot 23 when viewed from the laser beam incident surface 5 a of the transparent material depends on the length in the depth direction of the processing mark 6 obtained by the focused spot 23. As for the length, when the energy per laser pulse is small, the length of the processing mark obtained by the non-linear effect is also about 1 μm, and the energy per pulse becomes large. Accordingly, the length of the processing mark is increased, and in the first embodiment, the maximum length is about 200 μm as an example. For this reason, the interval in the depth direction of the focused spot is set in the range of 1 μm or more and 200 μm or less as an example.

  Also in the first modification, when the transparent materials 51 and 52 are viewed from the direction on the side where the branched laser beam 21 is irradiated, the branched laser beams 21 are arranged in a straight line, and the transparent materials 51 and 52 are arranged. When condensing at different depths from the laser beam incident surface 5a, the depth of the condensing point (condensing spot) 23, which is the forefront in the traveling direction of the cutting line, is the deepest, The depth of the condensing point (condensing spot) 23 corresponding to the last is close to the outermost surface of the transparent materials 51 and 52 on the laser beam incident side, and the other condensing points (condensing spots) 23 are the two condensing points. The upper transparent material 51 and the lower transparent material 52 can be processed at the same time by gradually changing the depth so as to smoothly connect the points.

  Further, further forward of the condensing point (condensing spot) 23 corresponding to the forefront of the cutting line in the traveling direction and further rearward of the condensing point (condensing spot) 23 corresponding to the rearmost in the traveling direction of the cutting line, respectively. By adding one to several condensing points (condensing spots) 23, it is possible to obtain a processing width larger than the thickness of the entire layer in which the transparent materials 51 and 52 are stacked. Thus, by providing the additional condensing point (condensing spot) 23, the condensing point (condensing spot) 23 in the transparent materials 51 and 52 by the curvature of the transparent materials 51 and 52 or the yawing or pitching of the stage 8 is provided. It is possible to suppress the occurrence of unprocessed portions on the outermost surface or the lowermost surface due to fluctuations in the relative position. Therefore, the occurrence of microcracks on the outermost surface or the lowermost surface is reduced, and an improvement in bending strength is expected.

  FIG. 4 is a schematic diagram of processing when the optical barrel shown in FIG. 3 is rotated. The stage 8 holds the transparent materials 51 and 52 on its upper surface, and can be moved in the X direction and the Y direction perpendicular to each other by the stage driving device 8x.

  The rotary lens barrel 4 is an optical unit 10B including a DOE 41 (FIG. 3), a condenser lens 42 (FIG. 3), and a wedge plate 43 (FIG. 3). 2 and cutting the transparent materials 51 and 52 along the cutting line 9 including the curve, the tangential direction (traveling direction vector) of the curve and the direction connecting the arrangement of the spots 23 as shown in FIG. Are configured to control the rotation angle of the rotary lens barrel 4 so that they always coincide. According to this configuration, it becomes possible to form the processing trace 6 (FIG. 1) in an arbitrary curved shape inside the transparent materials 51 and 52, and the upper transparent material 51 (FIG. 1) and the lower transparent material 52 are formed. In the display panel 5 to which (FIG. 1) is bonded, the upper and lower transparent materials 51 and 52 can be simultaneously cut along an arbitrary curve, which is particularly effective.

  According to the first embodiment, the DOE 41 and the single condensing lens 42 have the divided condensing spot 23 of the branched laser beam 21 within a minute distance, and the optical mirror including the DOE 41 and the condensing lens 42. By providing the cylinder 4 with the rotation drive device 44, the cutting line can be made to follow even if the planned cutting line is a free curve including a small radius of curvature. Further, by dispersing the condensed spot 23 in the depth direction of the transparent materials 51 and 52 to be cut, the transparent materials 51 and 52 can be cut by one scan. Accordingly, when the transparent material 51, 52 is cut, the optical drive device 44 can be rotated together with the optical barrel 4 by the rotation driving device 44 to control the branching direction of the laser beam 2, which is impossible in the past. Curve processing can be performed when cutting the transparent material. In addition, since the DOE 41 is used, the energy ratio of each of the branched laser beams 21 can be changed. Therefore, when the display 5 is composed of multiple layers of glass, depending on the depth to be processed. Thus, by adjusting the energy ratio, it becomes possible to reduce the difference in the machining state due to the depth.

(Second Embodiment)
FIG. 5 is a block diagram of a laser cutting optical unit 10C according to the second embodiment of the present invention configured as a zero-order light countermeasure optical unit at the time of multi-branching.

  In FIG. 5, the same components as those in FIGS.

  When multi-branching is performed using the DOE 41, the zero-order light 22 is generated due to manufacturing errors of the DOE 41 or other various factors (see FIG. 5A). In order not to interfere with the zero-order light 22, the branched pattern 21 a of the branched laser beam 21 needs to be branched in a direction that forms an angle with the incident direction of the laser beam 2. In such a case, the patterns of the laser beam 2 incident on the DOE 41 and the branched laser beam 21 are not linear, and when the rotating barrel 4 is configured, the processing plane (laser beam incident surface) of the display panel 5 The axis perpendicular to 5a and the 0th-order light 22 are parallel to each other, and the possibility that the 0th-order light 22 is transmitted to the processing point increases. Therefore, as shown in FIG. 5B, the laser beam 2 is moved to the DOE 41 by using the two prisms 45 and the like, with the optical axis 41a at an oblique angle with respect to the axis 5b perpendicular to the processing plane 5a of the display panel 5. The two prisms 45 and the DOE 41 are arranged so that the direction of the emitted light of the branched laser beam 21 pattern and the direction of the incident laser light on the first prism coincide with each other. At this time, the rotation center axis 40 of the rotary barrel 4 and the axis 5b perpendicular to the processing plane 5a of the display panel 5 are parallel to each other. As a result, the 0th-order light 22 can be easily shielded with a light-shielding mask or the like at a desired angle with respect to the axis 5b perpendicular to the processing plane 5a of the display panel 5, and each optical component is attached to the rotary lens barrel 4. It is possible to make the incident and outgoing optical axes coincide with each other and to easily rotate the lens barrel 4.

  According to the second embodiment, it is possible to perform curve processing at the time of cutting a transparent material, which has been impossible in the past. In addition, since the DOE 41 is used, the energy ratio of each of the branched laser beams 21 can be changed. Therefore, when the display 5 is composed of multiple layers of glass, depending on the depth to be processed. Thus, by adjusting the energy ratio, it becomes possible to reduce the difference in the machining state due to the depth.

  In the first embodiment and the second embodiment, a control unit 100 that drives and controls the rotation driving device 44 that rotates the rotating barrel 4 and the stage driving device 8x that drives the stage 8 may be provided. Good. In this case, when the transparent materials 51 and 52 are viewed from the direction on which the branched laser beam 21 is irradiated, the branched laser beams 21 are arranged in a straight line, and a condensing point (condensing spot) near the lowermost surface. ) The rotation angle of the optical barrel 4 by the rotation driving device 44 and the stage 8 by the stage driving device 8x so that a straight line vector in which 23 is forward is always directed in a direction tangent to the traveling direction of the cutting line. The movement direction may be synchronized with the control unit 100. Thus, when the cutting line draws a curve, an effect that the cutting width is suppressed to the minimum value can be obtained.

  Further, a vertical drive device that can be driven in the vertical direction (Z-axis) may be added to the stage 8 so that the stage 8 can be moved up and down. When the transparent materials 51 and 52 to be processed are distorted due to gravity or the like, the distortion is obtained by a method such as measuring the value in advance, and the value calculated by the control unit 100 based on the obtained distortion. Thus, the stage 8 may be moved up and down via a vertical driving device so as to cancel the influence of the distortion.

  In addition, it can be made to show the effect which each has by combining arbitrary embodiment or modification of the said various embodiment or modification suitably. In addition, combinations of the embodiments, combinations of the examples, or combinations of the embodiments and examples are possible, and combinations of features in different embodiments or examples are also possible.

  The laser cutting optical unit and the laser cutting device of the present invention have an optical unit that causes dispersion of laser light branched in a depth direction so as to be able to make a cut mark in a curved shape. It can also be applied to laser cutting applications such as glass panels.

DESCRIPTION OF SYMBOLS 1 Laser oscillator 10, 10B Laser cutting optical unit 11, 11B Laser cutting apparatus 2 Laser beam 20 The moving direction of a laser beam 21 Branched laser beam 22 0th order light 23 Spot 3 Mirror 4 Rotating lens barrel (an example of an optical lens barrel)
40 Rotation center axis 41 Diffractive optical element (DOE, example of optical element)
41a Optical axis 42 Condensing lens 43 Wedge plate 44 Rotation motor (an example of a rotation drive device)
45 Prism 5 Display panel 5a Laser beam incident surface (processing plane)
5b Axis perpendicular to the machining plane 51 Upper transparent material (an example of transparent material)
52 Lower transparent material (example of transparent material)
6 Processing trace 7 Spot distribution of processing points simultaneously irradiated 701 Processing width of spot 702 Dividing width of spot group 703 Permissible angle 71 Spot distribution processed initially 72 After optical barrel moves while rotating Spot distribution 8 Stage 8x Stage driving device 9 Cutting line 100 Control unit 102 Laser beam 123 to 130 Divided beam 135 Condensing lens group 145 Condensing point 146 by beam 130 Condensing point 171 by beam 123 Beam dividing means 183 to 190 Cavity 231 Laser head L Laser light W Wafer

Claims (8)

In an optical unit for performing processing by irradiating a transparent material with a laser beam,
An optical element for branching the laser beam into a plurality of branch laser beams;
A condensing lens on which all of the branched laser beams branched into the plurality by the optical element are incident;
A rotatable optical barrel having the optical element and the condenser lens;
A rotation driving device that rotates the optical barrel around a rotation center axis along a direction in which the laser beam is incident;
A laser cutting optical unit for performing laser cutting processing by rotating the optical lens barrel around the rotation center axis by the rotation driving device and condensing the branched laser beam at each spot inside the transparent material.   The laser cutting optical unit according to claim 1, wherein the optical element is a diffractive optical element.   By placing the optical axis of the optical element and the optical axis of the condenser lens obliquely with respect to the laser beam incident surface of the transparent material, the branched laser beam branched into the plurality of the laser beams of the transparent material The laser cutting optical unit according to claim 1, wherein the laser cutting optical unit focuses light at different depths from the laser beam incident surface. A wedge plate disposed on the exit side of the optical barrel;
3. The laser cutting optical unit according to claim 1, wherein the branched laser beams branched into the plurality are condensed at different depths from the laser beam incident surface of the transparent material.   When the transparent material is viewed from the direction of irradiation with the branched laser beam branched into the plurality, the branched laser beams are arranged in a straight line and have different depths from the laser beam incident surface of the transparent material. When condensing, the depth of the condensing point that is the forefront in the traveling direction of the cutting line is the deepest, and the depth of the condensing point that is the last in the traveling direction of the cutting line is the above-mentioned of the transparent material The depth is gradually changed so as to be close to the outermost surface on the incident side of the branched laser beam and to smoothly connect the other condensing points between the two condensing points. The laser cutting optical unit according to claim 1.   The transparent material has a structure in which two layers of plate-shaped objects are stacked, and the width in the depth direction where the branched laser beam is focused is larger than the thickness of all the layers in which the transparent material is stacked. The laser cutting optical unit according to any one of claims 3 to 5.   The distance of the depth direction between the condensing spots of the said branched laser beam when it sees from the laser beam incident surface of the said transparent material shall be 1 micrometer or more and 200 micrometers or less, It is any one of Claims 3-6 Laser cutting optical unit. A stage on which the transparent material is mounted;
The laser cutting optical unit according to any one of claims 1 to 7,
When the transparent material is viewed from the direction irradiated with the branched laser beam branched into the plurality, the branched laser beams are arranged in a straight line, and the direction is tangent to the traveling direction of the cutting line. A laser cutting apparatus comprising a control unit that moves the optical barrel while synchronizing the rotation angle of the optical barrel and the moving direction of the stage so as to always face in a certain direction.

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