JP4667329B2 - Laser processing equipment - Google Patents

Description

  The present invention relates to a laser processing apparatus for making a blind hole or a through hole in an electronic material such as a printed circuit board material or a ceramic green sheet.

  Since processing objects such as printed circuit board materials and ceramic green sheets have a planar shape, a conventional laser processing apparatus, for example, uses two galvano scanners to two-dimensionally laser light as shown in FIG. Scanning is performed to irradiate the object to be processed, and hole making is performed (for example, Patent Document 1). Here, in order to facilitate understanding of the present invention, an outline thereof will be described with reference to FIG.

  FIG. 14 is a conceptual diagram illustrating a general configuration and operation of a laser processing apparatus. The laser processing apparatus shown in FIG. 14 includes galvano scan mirrors 2a and 2b, galvano scanners 3a and 3b, an fθ lens 4, and a table on which a workpiece 5 is placed.

  The galvano scan mirror 2a is a first galvano scan mirror that first receives laser light 1 output from a laser oscillator (not shown), and its mirror surface is displaced and incident as the drive shaft of the galvano scanner 3a rotates. The optical axis of the laser beam 1 is deflected and scanned in one direction (for example, the X-axis direction) and sent to the second galvano scan mirror 2b. The galvano scan mirror 2b that receives the second laser beam has its mirror surface displaced with the rotation of the drive shaft of the galvano scanner 3b, and another direction (currently orthogonal to the optical axis of the incident laser beam 1). In this example, the beam is deflected and scanned in the Y-axis direction and sent to the fθ lens 4. As described above, the fθ lens 4 condenses and irradiates the laser beam scanned two-dimensionally in the XY plane onto the workpiece 5. As a result, a large number of machining holes 6 are formed in the machining workpiece 5 in the scan area 7 which is a range in which the laser light 1 can be two-dimensionally scanned by the galvano scanners 3a and 3b.

  By the way, the productivity of laser processing largely depends on the positioning speeds of the two galvano scanners, as can be understood from the above description. For this reason, the positioning speed of the galvano scanner continues to improve year by year. However, since it is a mechanical operation, it is naturally limited by problems such as vibration and heat generation. In preparation for the case where the positioning speed reaches the limit, a method for increasing the number of beams that can be irradiated simultaneously as a method for improving productivity is being studied and put into practical use. There are two ways to do this. One is a multi-axis method as shown in FIG. 15, and the other is a method using a holographic optical element (HOE) as shown in FIG.

  FIG. 15 is a conceptual diagram illustrating a configuration example of a multi-axis laser processing apparatus. In FIG. 15, laser heads 9a and 9b are a set of galvano scan mirrors 2a and 2b, galvano scanners 3a and 3b, and an fθ lens 4, respectively, and are supplied with laser light 1 dispersed by a spectroscope 8 at the same time. In addition, the machining work 5 is configured to be drilled simultaneously.

  FIG. 15 shows a configuration example of two heads. At present, attempts are being made to improve productivity by increasing the number of heads to four. However, in this case, the number of galvano scanners and galvano scan mirrors must be increased from one set to two sets and four sets, and the number of expensive fθ lenses must be increased to two and four. There are many problems.

  FIG. 16 is a conceptual diagram illustrating spectroscopy by HOE applied to the laser processing apparatus shown in FIG. As shown in FIG. 16, the HOE 10 can split the laser beam 1 in a plurality of directions. Therefore, in the laser processing apparatus using the HOE 10, the processing pattern becomes a processing pattern having a certain shape in which a plurality of round holes are combined. Although there is a limitation, since the number of laser beams can be increased without increasing the number of laser heads, the above problem can be avoided and the speed can be reliably increased.

  Explaining the processing method in the laser processing apparatus using the HOE 10, the HOE 10 is provided in the input stage of the first galvano scan mirror 2a, and uses the coherence of the laser to divide the passing beam into small pieces. It is designed to interfere with each other with a phase difference, strengthening in some places and weakening in others. Since the information before the HOE incidence is transmitted to the reinforcing interference fringes, it is processed as if one beam was divided into a plurality of parts.

  Thus, although there is a limitation that the processing pattern is limited, a processing method using HOE (hereinafter abbreviated as “HOE processing”) is very advantageous in productivity in order to repeatedly perform the same pattern processing. Use cases of HOE processing are increasing, mainly in the electronic component industry where the cost of products must be reduced.

JP 2002-66769 A

  However, since blind holes and through holes formed in the workpiece are very small, the positional accuracy during processing is also a very important factor. However, even with conventional HOE processing or processing that does not use HOE, In conventional long hole processing in which the shape is an ellipse or rectangle, it is difficult to improve the position accuracy of the processed hole.

  Specifically, in the conventional HOE processing, there is little distortion at the center of the scan area and it is in a good processing state, but as described below (FIGS. 17 to 19), the galvano scan mirror is tilted and the laser is When the light irradiation position is brought to the periphery of the fθ lens (that is, the periphery of the scan area), distortion and shape inclination occur (see FIG. 20). This is the same in the case of performing the above long hole processing even in single hole processing not using HOE (see FIG. 21). This is the main cause of the deterioration of the positional accuracy at the time of HOE processing or long hole processing in single hole processing without using HOE, and it is necessary to reduce it as much as possible.

  Hereinafter, with reference to FIG. 17 to FIG. 19, a phenomenon in which a distortion or a shape inclination occurs in the periphery of the scan area will be described. FIG. 17 is a ray tracing diagram for explaining two-dimensional scanning by two galvano scanners and two galvano scan mirrors in the laser processing apparatus shown in FIG. 18 shows the relationship between the light beam direction and the scanning angles η and ξ and the elevation angle φ in FIG. 17. FIG. 18 shows the cosine component and sine component in the light beam direction, and (2) the cosine component in the light beam direction. It is a figure which calculates | requires a sine component and a tangent component. FIG. 19 is a diagram showing the relationship between the distortion on the screen shown in FIG. 17 and the elevation angle φ.

  In FIG. 17, point A indicates the mirror surface position of the first galvano scan mirror 2a, and point B and the point B 'immediately above it indicate the mirror surface position of the second galvano scan mirror 2b. Now, assuming that point B is the origin and three orthogonal axes of X, Y, and Z are defined as indicated by arrows in the figure, the first reflection is performed by the first galvano scan mirror 2a at point A. The first galvano scan mirror 2a at the point A reflects incident laser light with an angle η deflected in the Y-axis direction. This reflected laser light is incident on the mirror surface position B ′ of the second galvano scan mirror 2 b at the point B, where it is reflected by a deflection operation in the XZ plane and takes a path toward the fθ lens 4. In FIG. 17, the fθ lens 4 whose lens surface is parallel to the XY plane shows the first quadrant divided into four.

  At this time, if the deflection angle from the Z axis to the X axis at the second galvano scan mirror 2b at point B is ξ, the laser beam emitted from a laser oscillator (not shown) is scanned in the Y axis direction and the X axis direction. Is incident on an upper position separated from the Y-axis direction in the first quadrant of the fθ lens 4 along the optical path R, which is η and ξ, respectively, and is the scan area 7 immediately below shown in FIG. 11 is collected at the corners.

The direction cosines L, M, and N of the optical path R at this time are as shown in FIG.
L = cos η · sin ξ (1)
M = sin η (2)
N = cos η · cos ξ (3)
It becomes.

The upper position in the first quadrant of the fθ lens 4 that the optical path R strikes is represented by an elevation angle φ from the origin to the Y-axis direction in the XY plane.
Tanφ = M / L = tan η / sinξ (4)
It becomes.

  Because of such a scanning deflection angle, when a two-dimensional image is created by the optical axis rotationally symmetric fθ lens 4, image distortion inevitably occurs in the peripheral portion of the screen 11. That is, when the deflection angles ξ and η are deflections of equal angular velocities and the maximum deflection angles are equal, if an ideal fθ lens is used, the horizontal and vertical directions passing through the center of the screen (that is, the X axis in the first quadrant). There is no distortion on the upper and Y axes). However, when the shake angle η and the shake angle ξ are changed to be the same, the elevation angle φ does not become 45 degrees from the equation (4), and the corner of the figure on the image plane is shown by a solid line in FIG. It will have such distortion.

  Since it is difficult to correct this distortion with the fθ lens 4, according to the conventional technique, the swing angles ξ and η of the two galvano scanners 3 a and 3 b are changed from tan η = sin ξ from the equation (4). In addition to this, it is possible to cope with the problem by performing fine adjustment and control based on the characteristics depending on the location of the fθ lens 4.

  However, by controlling the deflection angle by the galvano scanners 3a and 3b, the position of the corner having distortion indicated by the solid line in FIG. 19 can be brought to the correct position indicated by the dotted line, but the HOE 10 is moved to the original distorted position. As a result, a dispersed pattern is formed.

  FIG. 20 is a schematic diagram for explaining the generation of distortion of the HOE spectral pattern at the corner of the scan area. That is, if the distortion at this corner is corrected by the deflection angle control by the galvano scanners 3a and 3b as described above, the HOE spectral pattern 12 itself is rotated as shown in FIG. It happens that the round hole is formed inclined.

  FIG. 21 is a schematic diagram for explaining the occurrence of distortion of the long hole pattern at the corners of the scan area in the case of performing processing for opening a long hole such as an ellipse or a rectangle without using the HOE. In drilling without using the HOE, drilling is performed in a shape corresponding to the opening shape of the mask. Among them, in the case of round processing, since the circle remains round even when the angle is added, the inclination is not a problem at all. However, in the case of an elongated hole shape such as an ellipse or a rectangle, the phenomenon shown in FIG. 19 occurs in the same manner, and the elongated hole pattern 13 rotates as shown in FIG.

  As described above, when irradiating as a certain HOE spectral pattern combining a plurality of round holes using HOE, or when processing a long hole such as an ellipse or a rectangle even when processing a single hole without using HOE, Since an inclination occurs in the shape and this inclination causes a positional shift, conventionally, it has been difficult to improve the position accuracy of the processed hole. In order to improve the position accuracy of the processed hole, it is necessary to minimize the rotation angle of the processed pattern described above, but how to achieve it is a problem.

  The present invention has been made in view of the above, and when processing a plurality of holes simultaneously using HOE or when performing a single long hole processing without using HOE, the position accuracy of the processing holes is easily achieved. It is an object of the present invention to obtain a laser processing apparatus capable of improving and reducing the generated distortion.

  To achieve the above object, the present invention provides a laser oscillator that emits laser light, a set of galvano scanners that two-dimensionally scan the laser light emitted from the laser oscillator, and the set of galvano scanners. A first galvanometer disposed on the oscillator side on the laser optical axis of the set of galvano scanners. The laser beam incident on the scanner is set so that the major axis direction side of the major axis and minor axis existing in the irradiation pattern faces the axial direction side of the drive shaft of the first galvano scanner. And

  According to the present invention, the direction of the irradiation pattern in the laser beam incident on the optical scanning system that generates the two-dimensional scanning laser beam irradiated on the workpiece (work) to be drilled is determined. Specifically, the major axis direction side of the major axis and the minor axis existing in the irradiation pattern of the laser beam incident on the first galvano scanner that receives the laser beam first is not in a direction orthogonal to the drive axis, Since the irradiation pattern rotation angle at the corner of the scan area can be reduced by simply taking a simple measure of adjusting and setting the drive shaft to be in the axial direction, preferably in the parallel direction, the HOE can be reduced. The position accuracy can be improved when a plurality of holes are processed at the same time, and the occurrence of distortion can be suppressed low when a single long hole is processed without using the HOE.

  According to the present invention, when processing a plurality of holes simultaneously using HOE, or when performing a single long hole processing without using HOE, the positional accuracy of the processed holes is easily improved and distortion generated is reduced. There is an effect that can be achieved.

  Exemplary embodiments of a laser processing apparatus and a laser processing method according to the present invention will be described below in detail with reference to the drawings.

Embodiment 1 FIG.
FIG. 1 is a ray tracing diagram for explaining the principle of a laser processing method performed by a laser processing apparatus using an HOE according to Embodiment 1 of the present invention. FIG. 2 is an enlarged view of ray tracing in the mirror plane of the first galvano scan mirror closer to the HOE placement position H in FIG. FIG. 3 is an enlarged view of ray tracing in the normal direction of the mirror surface of the first galvano scan mirror shown in FIG. FIG. 4 is an enlarged view of ray tracing in the mirror plane of the second galvano scan mirror that receives the reflected light from the first galvano scan mirror in FIG. FIG. 5 is a diagram for explaining the rotation angle of the HOE spectral pattern within the light receiving surface of the fθ lens that receives the reflected light from the second galvano scan mirror in FIG. 1. For the convenience of explanation, the names and symbols used in the prior art such as FIG.

  In FIG. 1, the arrangement position H of the HOE, the first and second galvano scan mirrors 2a and 2b, and the fθ lens 4 are shown. If the three orthogonal axes X, Y, and Z are defined as indicated by arrows in the figure with the mirror surface center of the galvano scan mirror 2b as the coordinate origin (0, 0, 0), the arrangement position H of the HOE is (X, Y , Z) = (− l, −k, 0). A galvano scan mirror 2a is disposed at a position separated from the position H by an optical distance k in the Y-axis direction, and a galvano scan mirror 2b is disposed at a position separated from the galvano scan mirror 2a by an optical distance l in the X-axis direction. The fθ lens 4 is disposed at a position separated from the scan mirror 2b by an optical distance s in the Z-axis direction.

  As described in FIG. 14, the mirror surface of the galvano scan mirror 2a is displaced with the rotation of the drive shaft of the galvano scanner 3a. The drive shaft of the galvano scanner 3a is oriented in the Z-axis direction. The mirror surface of the galvano scan mirror 2b is displaced with the rotation of the drive shaft of the galvano scanner 3b. The drive shaft of the galvano scanner 3b is oriented in the Y-axis direction.

  Now, since the spectral pattern by HOE is repeated with regularity, it can be made into a lattice shape as well as a linear shape. In any case, the spectral pattern by HOE is a processing pattern having a certain shape in which a plurality of round holes are combined, and has a longitudinal direction. Therefore, here, the pattern shape is simplified by replacing it with a rectangle, and after the rectangular pattern is reflected and deflected by the galvano scan mirrors 2a and 2b, it is the scan area 7 immediately below shown in FIG. When the image was transferred onto the screen 11, how the side of the rectangle rotated was examined. Note that the items described here can also be applied as they are when a hole shape other than a round shape such as a single ellipse or rectangle is opened by replacing the HOE with a mask.

  In FIG. 1, three light rays A1, A2, A3 are generated from a position H, and a position A {(X, Y, Z) = (− 1, 0, 0) on the galvano scan mirror 2a that receives them first. } On a plane (XZ plane) perpendicular to the Y-axis, as shown in detail in FIG. 2, a rectangle with one side of 2n and 2m is drawn, and its vertex is set to three rays A1, A2, A3. To pass. These three rays A1, A2 and A3 can be expressed as [Equation 1].

  Further, as shown in FIG. 3, the mirror surface of the galvano scan mirror 2a is changed from the state shown by the broken line where the angle of incidence / reflection is 45 degrees to the state shown by the solid line where the incident angle is “45 degrees + η”. If these three rays A1, A2, and A3 are reflected at points P1, P2, and P3 on the galvano scan mirror 2a when tilted only by the angle, the points P1, P2, and P3 on the galvano scan mirror 2a are reflected. Can be expressed as [Equation 2].

  If the size of the mirror surface of the galvano scan mirror 2a is not limited, it can be expressed by the equation α (x + 1) + βy = 0, so that the three light beams A1, A2, and A3 are the mirror surfaces of the galvano scan mirror 2a. Assuming that the reflected rays are B1, B2, and B3, the three reflected rays B1, B2, and B3 can be expressed as [Equation 3].

  Next, in the galvano scan mirror 2b having the YZ plane including the coordinate origin (0, 0, 0) as the mirror plane, as shown in detail in FIG. 4, the mirror plane has the Y axis as the rotation center, and the -X axis. From the side to the + Z-axis side. FIG. 4 shows a case where the angle is further displaced by an angle ξ toward the + Z-axis side from a state inclined 45 degrees from the −X-axis side toward the + Z-axis side. Thus, the mirror surface of the galvano scan mirror 2b having the deflection angle ξ can be expressed by the equation γx + δy = 0 using γ and δ where γ = sin ξ−cos ξ and δ = cos ξ + sin ξ.

  If the above-mentioned three reflected light beams B1, B2, B3 are reflected at points Q1, Q2, Q3 on the mirror surface of the galvano scan mirror 2b having such a deflection angle ξ, the points Q1, Q2, Q3 can be expressed as [Equation 4].

  If the reflected light rays are C1, C2, and C3, the three reflected light rays C1, C2, and C3 can be expressed as [Equation 5].

  If the points where these three reflected rays C1, C2, C3 intersect the surface of the fθ lens 4 are R1, R2, R3, then R1, R2, R3 become rectangular vertices, and these vertices R1, R2, R3 Can be expressed as [Equation 6].

  Here, as shown in FIG. 5, the angle formed by the line connecting the vertex R1 and the vertex R2 with respect to the vertical direction (Y-axis direction) is θ12, and the line connecting the vertex R2 and the vertex R3 is the horizontal direction (X If the angle formed with respect to the (axial direction) is θ23, the angles θ12 and θ23 are parameters representing the degree of rotation of the HOE spectral pattern.

  Therefore, the angles θ12 and θ23 are plotted against the change of one deflection angle η, and the change of the rotation angle of the HOE spectral pattern (that is, the degree of positional deviation at the four corners of the scan area shown in FIG. 19). As a result, the characteristics shown in FIGS. 6 and 7 were obtained. 6 is a diagram showing the relationship between the deflection angle η and the angles θ12 and θ23 defined as shown in FIG. 5 when m and n shown in FIG. 2 are m> n. FIG. 7 is a diagram showing the relationship between the deflection angle η and the angles θ12 and θ23 defined as shown in FIG. 5 when m and n shown in FIG. 2 are m <n.

  However, in this calculation, the other deflection angle ξ was changed so that the elevation angle φ shown in Equation (4) was 45 degrees. Specifically, tan η = sin ξ and Tanφ = 1. The optical distances l, k, and s are values of the actual optical system, and the remaining parameters m and n are m = 12, n = 6 as an example of m> n (FIG. 6), As an example of m <n, the case where m = 6 and n = 12 (FIG. 7) was adopted.

  From this calculation result, as the deflection angle η increases, the angle θ12 shows a large tendency to increase both in the case of m> n and m <n, so that the rotation angle increases and the degree of misalignment deteriorates. Since the angle θ23 shows a slight increase tendency, the increase in the rotation angle due to this is extremely small. The rotation angle due to the angle θ23 is slightly increased when m <n than when m> n, but the increase in the rotation angles of the angles θ12 and θ23 as a whole with respect to the increase of the deflection angle η is calculated. It turned out to be smaller.

  FIG. 8 is a diagram showing the relationship between the magnitude relationship between m and n shown in FIG. 2 and the rotation angle maximum value based on the angles θ12 and θ23 defined as shown in FIG. As shown in FIG. 8, the maximum value of the rotation angle is greater for the angle θ12 than for the angle θ23, but obviously when n is greater than m, the angle θ12 and the angle θ23 are greater. As a whole, the maximum rotation angle becomes small.

  This is because the longitudinal direction side of the HOE spectral pattern output from the HOE is the rotation axis of the galvano scan mirror 2a as an incident mode to the mirror surface of the first galvano scan mirror 2a that first receives the laser beam output from the HOE. If it is set to an incident mode that is preferably in a parallel direction so as to face a certain Z-axis direction, the rotation angle at the time of transferring the processed shape to the workpiece can be kept low, that is, at the four corners of the scan area. This means that the displacement of the position becomes smaller. This measure can be realized by determining the installation mode of the HOE itself when there is no optical system between the HOE and the galvano scan mirror 2a. If an optical system exists, the HOE and its optical system are included. This can be realized by adopting the above-described incident mode as a whole.

  Next, since the validity of the “incident aspect on the mirror surface of the first galvano scan mirror 2a” found from the calculation results as described above was specifically verified by an actual machine, the verification contents are shown in FIGS. 12 and Table 1 will be described. In the actual machine (FIGS. 11 and 12), it is assumed that there is no optical system between the HOE and the first galvano scan mirror 2a. An optical system between the HOE and the first galvano scan mirror 2a that guides the laser beam that has passed through the HOE to the galvano scan mirror 2b after being transmitted or reflected by one or more optical elements such as lenses and mirrors. Is present, the measure of “incident on the mirror surface of the first galvano scan mirror 2a” may be taken in the optical system or the like.

  FIG. 9 conceptually shows the HOE spectral pattern at the four corners of the scan area. As shown in FIG. 9, when the HOE is set to (1) a direction in which the longitudinal direction side of the HOE spectral pattern 14a is parallel to the drive axis direction (X-axis direction in FIG. 9) of the first galvano scanner 3a. (This is referred to as “vertical placement”) and (2) a direction (Y) in which the longitudinal direction side of the HOE spectral pattern 14b is orthogonal to the drive axis direction (X-axis direction in FIG. 9) of the first galvano scanner (Axial direction) and a case where it is set in a direction parallel to this (this is referred to as “horizontal placement”) were prepared.

  And the laser processing apparatus using HOE is the structure which provided HOE10 in the input stage of the 1st galvano scan mirror 2a in the structure shown in FIG. 14, as shown in FIG. 11 and FIG. The HOE 10 separates the laser beam 1 output from a laser oscillator (not shown) as shown in FIG. 3 and supplies the spectrum to the first galvano scan mirror 2a. Although not shown in FIGS. 11 and 12, as shown in FIG. 14, the first galvano scan mirror 2a is connected to the drive shaft of the first galvano scanner 3a. The second galvano scan mirror 2b is connected to the drive shaft of the second galvano scanner 3b.

  In such a laser processing apparatus using the HOE, the laser processing is performed by placing the HOE 10 in the vertical position shown in FIG. 9 (1) (FIG. 11) and in the horizontal position shown in FIG. 9 (2). This was done (FIG. 12), and the magnitude of the rotation angle at the four corners of the scan area 7 (that is, the degree of positional deviation) was compared.

  In this case, as shown in FIG. 10, at the four corners of the scan area, (1) driving of the first galvano scanner on the longitudinal direction side of the HOE spectral pattern 14a in the vertical position shown in FIG. The rotation angles θ1 and θ2 from the axial direction (X-axis direction in FIG. 10), and (2) the first galvano scanner on the longitudinal direction side of the HOE spectral pattern 14b in the horizontal position shown in FIG. The rotation angles θ1 and θ2 from the direction (Y-axis direction) orthogonal to the drive axis direction (X-axis direction in FIG. 10) were obtained by changing the area of the scan area (see Table 1).

  Table 1 shows changes in the rotation angles θ1 and θ2 between the vertical placement and the horizontal placement when the area of the scan area is increased to 26 mm, 33 mm, 43 mm, and 65 mm. As can be understood from Table 1, when the scan area is increased, the pattern rotation angle is also increased. However, it can be clearly understood that the rotation angle can be suppressed smaller in the case of vertical placement. That is, the direction in which the longitudinal direction side of the HOE spectral pattern is aligned with the direction parallel to the drive axis direction of the first galvano scanner (in the case shown in FIG. 11) is aligned with the direction parallel to the direction perpendicular to the drive axis. The correctness of the above-described examination result that the rotation angle can be suppressed smaller than the case (the case shown in FIG. 12) is shown.

  Thus, according to the first embodiment, in the laser processing apparatus that simultaneously processes a plurality of holes using the HOE, the longitudinal direction side of the HOE spectral pattern is set in a direction orthogonal to the drive axis of the first galvano scanner. The position accuracy of the processed hole can be improved by a simple measure that is not oriented but preferably aligned in the direction parallel to the drive axis of the first galvano scanner. This measure is practically realized by adjusting the arrangement position of the HOE (including the optical system, if any), but it can also be realized by adjusting the drive axis direction of the first galvano scanner. be able to.

Embodiment 2. FIG.
FIG. 13 is a conceptual diagram illustrating the principle of a laser processing method performed by a laser processing apparatus that does not use an HOE according to Embodiment 2 of the present invention. As shown in FIG. 13, in the laser processing apparatus that performs single hole processing without using the HOE, the mask 15 is provided at the input stage of the first galvano scan mirror 2a in the configuration shown in FIG. The shape is transferred and processed. Although not shown in FIG. 13, as shown in FIG. 14, the first galvano scan mirror 2a is connected to the drive shaft of the first galvano scanner 3a. The second galvano scan mirror 2b is connected to the drive shaft of the second galvano scanner 3b.

  In this case, particularly when the processed hole shape is a shape having a longitudinal direction and a short direction such as an ellipse or a rectangle, as described above, an inclination occurs at the corner of the scan area, and the transferred shape itself Distortion will occur.

  Accordingly, in the same manner as in the first embodiment, the mask 15 or the first galvano scanner 3a is arranged in the longitudinal direction (the maximum length direction) side of the mask transfer shape pattern in the drive axis direction of the first galvano scanner 3a. If the mask 15 or the first galvano scanner 3a is installed so as to be in a parallel direction, preferably, the distortion generated in the long hole pattern 16 due to this inclination can be minimized. it can.

  In FIG. 13, there is no special optical system between the mask 15 and the galvano scan mirror 2a. However, an optical element is disposed between the mask 15 and the galvano scan mirror 2a. Even so, the mask 15 is formed so that the longitudinal direction side of the processed hole shape in the laser light incident on the first galvano scan mirror 2a is in a direction parallel to the drive axis direction of the first galvano scanner. Or if the 1st galvano scanner is arrange | positioned, the same distortion reduction effect will be acquired.

  Thus, according to the second embodiment, in the laser processing apparatus that performs a single long hole processing without using the HOE, the longitudinal direction side of the mask transfer shape pattern of the mask is the drive axis direction of the first galvano scanner. It is possible to reduce the distortion of the shape that occurs when processing a long hole shape other than a round hole shape such as an ellipse or a rectangle with a simple measure of aligning in a direction parallel to the side, preferably parallel. it can.

  As can be understood from the description in the first and second embodiments, the two galvano scanners in which the two-dimensional scanning laser light to be irradiated to the workpiece to be drilled is arranged at a predetermined optical distance on the laser optical axis. In the laser processing to be generated, when performing the simultaneous processing of a plurality of holes or the processing of a single long hole, the long axis and the short axis exist in the irradiation pattern to the workpiece. The laser beam incident on the mirror surface that is rotationally driven by the first galvano scanner disposed on the laser beam generation source side on the laser beam axis is the long axis direction side of the irradiation pattern of the drive shaft of the first galvano scanner. If it is set so as to face in the axial direction, preferably in the parallel direction, the positional accuracy of a plurality of holes to be machined simultaneously can be improved. It is possible to reduce the distortion generated in a single machining slot.

  As described above, the laser processing apparatus according to the present invention improves the positional accuracy of a processed hole when a plurality of holes are processed simultaneously using HOE or when a single long hole is processed without using HOE. It is useful for reducing the distortion.

It is a ray tracing diagram explaining the principle of the laser processing method implemented with the laser processing apparatus using HOE by Embodiment 1 of this invention. FIG. 2 is an enlarged view of ray tracing in a mirror plane of a first galvano scan mirror closer to the HOE arrangement position H in FIG. 1. FIG. 3 is an enlarged view of ray tracing in the normal direction of the mirror surface of the first galvano scan mirror shown in FIG. 2. FIG. 3 is an enlarged view of ray tracing in a mirror plane of a second galvano scan mirror that receives light reflected by the first galvano scan mirror in FIG. 1. It is a figure explaining the rotation angle of the HOE spectral pattern in the light-receiving surface of the f (theta) lens which receives the reflected light by the 2nd galvano scan mirror in FIG. FIG. 6 is a diagram showing a relationship between a deflection angle η and angles θ12 and θ23 defined as shown in FIG. 5 when m and n shown in FIG. 2 are m> n. FIG. 6 is a diagram showing a relationship between a deflection angle η and angles θ12 and θ23 defined as shown in FIG. 5 when m and n shown in FIG. 2 are m <n. It is a figure which shows the relationship between the magnitude relationship of m and n shown in FIG. 2, and the rotation angle maximum value by angle (theta) 12 and (theta) 23 defined as shown in FIG. The HOE spectral pattern at the four corners of the scan area is shown, and the longitudinal direction of the HOE spectral pattern is set substantially parallel to the drive axis direction of the first galvano scanner, and the longitudinal direction of the HOE spectral pattern Is a conceptual diagram at the time of horizontal placement in which is set substantially parallel to a direction orthogonal to the drive axis direction of the first galvano scanner. It is a figure which shows the relationship between the rotation angle in the case of calculating | requiring the rotation angle of the HOE spectral pattern in the four corners of a scan area by changing the area of a scan area, and the drive axis direction of a 1st galvano scanner. It is a conceptual diagram of the laser processing performed in the case of the vertical installation shown to FIG. 9 (1). It is a conceptual diagram of the laser processing performed in the case of the horizontal installation shown in FIG.9 (2). It is a conceptual diagram explaining the principle of the laser processing method implemented with the laser processing apparatus which does not use HOE by Embodiment 2 of this invention. It is a conceptual diagram explaining the general structure and operation | movement of a laser processing apparatus. It is a conceptual diagram which shows the structural example of the multi-axis laser processing apparatus. It is a conceptual diagram explaining the spectroscopy by HOE applied to the laser processing apparatus shown in FIG. FIG. 15 is a ray tracing diagram for explaining two-dimensional scanning by two galvano scanners and two galvano scan mirrors in the laser processing apparatus shown in FIG. 14. FIG. 17 shows the relationship between the light beam direction, the scanning angle η, ξ, and the elevation angle φ, and is a diagram for obtaining a cosine component and a sine component in the light beam direction, and a diagram for obtaining a cosine component, a sine component, and a tangent component in the light beam direction. It is a figure which shows the relationship between the distortion on the screen shown in FIG. 17, and elevation angle (phi). It is a schematic diagram explaining generation | occurrence | production of distortion of the HOE spectral pattern in the corner | angular part of a scan area. It is a schematic diagram explaining the occurrence of distortion of the long hole pattern at the corner of the scan area when performing processing for opening a long hole such as an ellipse or a rectangle without using the HOE.

Explanation of symbols

1 Laser light 2a Galvano scan mirror (first galvano scan mirror)
2b Galvano scan mirror (second galvano scan mirror)
3a Galvano scanner (first galvano scanner)
3b Galvano scanner (second galvano scanner)
4 fθ lens 5 Processing workpiece 6 Processing hole 7 Scan area 8 Spectrometer 9a, 9b Laser head 10 Homographic optical element (HOE)
11 Screen 12 HOE Spectral Pattern 13 Slotted Hole Pattern 14a HOE Spectral Pattern at Vertical Position 14b HOE Spectral Pattern at Vertical Position 15 Mask 16 Slotted Hole Pattern η, ξ Swing Angle (Scanning Angle)
φ Elevation angle

Claims (3)

A laser oscillator that emits laser light;
A set of galvano scanners for two-dimensionally scanning the laser light emitted from the laser oscillator;
An fθ lens that condenses and irradiates laser light that is two-dimensionally scanned by the set of galvano scanners on a workpiece;
The laser beam incident on the first galvano scanner disposed on the laser oscillator side on the laser optical axis in the set of galvano scanners is in the major axis direction of the major axis and the minor axis existing in the irradiation pattern. The laser processing apparatus is characterized in that the side is set to face the axial direction side of the drive shaft of the first galvano scanner. The laser light incident on the first galvano scanner is an output laser light of a laser spectroscopic unit that splits the laser light from the laser oscillator into a plurality of laser lights,
2. The laser processing apparatus according to claim 1, wherein the long axis direction side is a longitudinal direction side in a spectral pattern of laser light spectrally separated by the laser spectroscopic means. The laser beam incident on the first galvano scanner is an output laser beam of a mask that shapes the laser beam from the laser oscillator into a desired cross-sectional shape,
The laser processing apparatus according to claim 1, wherein the major axis direction side is a longitudinal direction side in an irradiation pattern of laser light shaped by the mask.

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