JP2002178182A - Laser beam machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser beam machine which can surely position laser beams oscillated from a laser oscillator at a high speed to a deflection point of an fθ lens. SOLUTION: The deflection point of the fθ lens 14 is previously aligned to a center Os of a reflecting surface 13a of a mirror 13 and an optical path shifter 7 is arranged between a mirror 5 and the mirror 13. The laser beam reflected by a reflecting surface 5a of the mirror 5 is parallelly moved by the optical path shifter 7 and is made incident on the center of the reflecting surface 13a of the mirror 13. All the laser beams pass the deflection point and intersect with the central axis of the fθ lens 14 at an angle determined by a processing position and therefore the laser beams transmitted through the fθ lens 14 are made incident perpendicularly on the processing surface. Consequently, the axis of the processed hole is perpendicular. The laser beams are parallelly moved by rotating the transmission type optical path shifter and therefore the responsive speed and the processing speed are made faster.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser beam emitted from a light source having a fixed optical axis, which is made incident on a predetermined position of an f.theta. The present invention relates to a laser processing device for performing processing.

[0002]

2. Description of the Related Art In a laser processing apparatus for making a hole in a printed circuit board with a laser beam or a laser processing apparatus for making a mark, a laser oscillator is generally fixed. Then, the laser light oscillated from the laser oscillator is made incident on the fθ lens via two rotatable reflecting mirrors whose rotation axes are arranged at twisted positions, and the laser beam is condensed on the work to perform processing. Here, the fθ lens having the focal length f is such that a ray passing through a predetermined point (referred to as a deflection point) on the central axis of the fθ lens and having an angle θ with respect to the central axis is at a distance from the central axis of the fθ lens in the focal plane. It is designed such that f × θ and the optical axis are incident (condensed) perpendicular to the focal plane. Therefore,
By changing the angle θ of the laser light at the deflection point with respect to the central axis of the laser light, the laser light can be positioned at an arbitrary position.

However, for example, the deflection point of the fθ lens is
When the reflector is positioned on the reflection surface of the reflector closer to the fθ lens, the optical axis of the laser beam does not pass through the deflection point when the reflector on the laser oscillator is rotated. For this reason, when drilling a hole by aligning the surface of the workpiece substantially with the focal plane, the hole is obliquely drilled, and a positional shift of the hole occurs between the front and back of the printed circuit board (or the bottom of the hole). In addition, when performing marking, the focal point deviates from the position set by the reflecting mirror, and processing accuracy is reduced.

In Japanese Patent Application Laid-Open No. Hei 5-228673, a third reflector is disposed between a laser oscillator and a reflector closer to the laser oscillator, and the third reflector is moved in the optical axis direction of the laser beam. Is controlled so that the center of the laser beam reflected by the reflector closer to the laser oscillator irradiates the center of the second mirror.

[0005]

In the case where marking is performed, that is, when the processed portion is continuous, the above-mentioned Japanese Patent Application Laid-Open No.
According to the technique disclosed in Japanese Patent No. 228673, the processing speed and the processing accuracy can be improved.

However, when drilling holes in a printed circuit board, the drilling positions are discontinuous, and about 1000 holes must be drilled per second. For this reason, the technique disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 5-228673 has a slow response and cannot be applied to an apparatus for processing about 1000 holes per second.

The present invention has been made in view of such a situation of the prior art, and an object thereof is to position a laser beam oscillated from a laser oscillator at a deflection point of an fθ lens quickly and reliably. An object of the present invention is to provide a laser processing device.

[0008]

In order to achieve the above object, the present invention provides a light source that oscillates a laser beam, and the light source is arranged on the optical axis of the laser beam, and the angle of the laser beam to the optical axis is set around the rotation axis. A first mirror that can be positioned freely and a rotation axis that is the first mirror;
A second mirror disposed at a position twisted with respect to the rotation axis of the mirror, and capable of being positioned around the rotation axis, and an fθ lens for condensing the laser light deflected by the two mirrors. In the laser processing apparatus, a transmission type optical path shifter that translates the laser light is provided between the light source and the fθ lens.

When the center of the second mirror is the deflection point of the fθ lens, the transmission type optical path shifter is disposed between the light source and the first mirror, and the first mirror is provided. The transmission-type optical path shifter is positioned so that the optical axis of the laser light deflected in the step (c) enters a predetermined point of the second mirror.

In the case where the center of the first mirror is the deflection point of the fθ lens, the transmission type optical path shifter is disposed between the first mirror and the second mirror. The optical axis of the laser beam reflected by the first mirror is Lta
n2ε (where ε is the rotation angle of the second mirror, and L is the distance between the axis of rotation of the first mirror and the axis of rotation of the second mirror). can do.

The transmission type optical path shifter is formed of two wedge-shaped transparent bodies in which one apex is opposed to the other base and the opposed faces are arranged in parallel, or both faces are parallel. It can be formed from a plate-shaped transparent body.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the illustrated embodiment.

FIGS. 1 and 2 show a configuration example of a laser beam machine according to a first embodiment of the present invention. FIG. 1 is a plan view and FIG. 2 is a side view. On the optical axis P of the laser oscillator 1, an aperture 2, a fixed mirror 3, a first mirror 5,
Optical path shifter 7, second mirror 13, and fθ lens 14
Is arranged.

The mirror 5 is supported by a motor 6 and can be positioned at any angle around a rotation axis M perpendicular to the plane of the drawing.

The optical path shifter 7 is composed of a wedge 8 and a wedge 9 which are formed of a material transparent to laser light and whose surface is provided with an antireflection coating. Wedges 8, 9
Are held by the holder 10a such that the apex angles are equal, the opposing surfaces are parallel and the apex side and the base side face each other. The holder 10a is supported by the motor 10, and can be positioned at an arbitrary angle with the direction perpendicular to the plane of FIG. 1 as a rotation axis.

The reference position of the optical path shifter 7 is such that the laser light reflected by the reflection surface 5a at the reference position is positioned on the side surface 8 of the wedge 8.
This is a position where the light is perpendicularly incident on a.

The mirror 13 is supported by a rotating shaft of the motor 12 and is freely positionable at an arbitrary angle about an axis N parallel to the plane of the drawing (that is, at a position twisted by 90 degrees with respect to the axis M). The center Os of the reflecting surface 13a (the point on the axis N, which is the center in the width direction and the longitudinal direction of the mirror 13) is located at the center Os of the mirror 13 from the wedge 9 of the laser beam that is perpendicularly incident on the side surface 8a of the wedge 8. It is positioned at a position where the transmitted light is incident on the axis N at right angles.

Lens 14 has a central axis S perpendicular to the paper surface,
In addition, the deflection point H is positioned so as to coincide with the center Os of the reflection surface 13a.

The control device 16 includes a motor 6, a motor 10,
The motor 12 and the laser oscillator 1 are controlled.

The workpiece 15 has a center axis S
It is fixed to fit.

Here, the function of the optical path shifter will be described with reference to FIG. Since the apex angles of the wedges 8 and 9 are equal and the opposing surfaces are parallel, the incident light K incident on the wedge 8 and the transmitted light k1 emitted from the wedge 9 are parallel. Therefore, as shown in FIG. 2A, when the holder 10a is rotated to the left and the wedges 8 and 9 are rotated from the positions indicated by the dotted lines to the positions indicated by the solid lines, the transmitted light k2 is different from the transmitted light k1. To move down. Also, as shown in FIG.
When the holder 10a is rotated right, the transmitted light k3 moves upward in the figure with respect to the transmitted light k1. That is, the holder 1
By rotating Oa, the transmitted light can be moved in parallel without changing the position of the incident light.

The operation of the laser beam machine according to the first embodiment configured as described above is as follows.

The control device 16 calculates the angle θy from the reference position of the reflecting surface 5a based on the Y coordinate of the processing location described in the processing program, and calculates the angle θy from the reference position of the reflecting surface 13a based on the X coordinate of the processing location. Is calculated. Further, based on the obtained angle θy, the angle α of the holder 10a that allows the laser light emitted from the optical path shifter 7 to enter the center Os is calculated or obtained from a table stored in advance. Then, the reflecting surface 5a is set to the angle θy,
After rotating the holder 3a by the angle θx and the holder 10a by the angle α, the laser oscillator 1 is operated to oscillate laser light.

The laser beam oscillated from the laser oscillator 1 is shaped by the aperture 2 and enters the optical path shifter 7 via the fixed mirror 3 and the reflecting surface 5a. Then, the optical axis of the transmitted light is translated by the optical path shifter 7,
The light enters the center Os. Then, through the fθ lens 14,
The light is focused on the surface of the work 15 (an image of the aperture 2 is formed), and the work 15 is processed. When the optical path shifter 7 is not rotated, as shown by a dashed line in FIG. 1, the transmitted light is incident on a point Os1 deviated from the center Os.

FIG. 4 is a view for explaining the incident angle of the laser beam in the Y-axis direction incident on the work 15. In this embodiment, the laser light reflected by the reflection surface 5a moves from the optical path A in parallel to the optical path B, and has a reflection angle 2θy (the reflection surface 5a
Is rotated θy from the reference position, the reflected light rotates 2θy. ), The center Os, that is, the deflection point H
Incident on. As a result, the laser light is perpendicularly incident on the surface of the work 15 in the Y-axis direction. In addition, since the deflection point H is on the axis N, the laser beam also enters the surface of the work 15 perpendicularly in the X-axis direction. Therefore, the axis of the processed hole becomes vertical. On the other hand, if the optical path shifter 7 is not rotated, the laser beam does not pass through the deflection point H, as indicated by the two-dot chain line, so that the work 15
, The axis of the processed hole is inclined.

In this embodiment, a combination of a pair of wedges is used as the optical path shifter, so that the amount of shift of the optical path with respect to the rotation angle (the distance to translate) is large. Therefore, the rotation amount for obtaining the required shift amount can be reduced, and the response speed of the optical path shifter can be improved.

Further, the laser beam is applied to the center Os of the mirror 13.
, It is not necessary to enlarge the reflecting surface 13a. As a result, the size of the mirror 13 can be reduced, and the positioning speed of the mirror 13 can be improved.

It should be noted that even if the shift amount of the laser beam by the optical path shifter 7 is slightly shifted, the shift amount with respect to the deflection point is almost compensated, so that the control accuracy of the rotation angle of the optical path shifter 7 is not so required.

The apex angles of the wedges 8 and 9 need not be the same. In this case, the incident light and the outgoing light are no longer parallel. However, by rotating the optical path shifter, the transmitted light can be moved in parallel, as in the case where the apex angle is the same.

The optical path shifter 7 may be disposed between the light source and the mirror 3 as in the case of a second embodiment described later.

FIG. 5 is a plan view showing an example of the configuration of a laser beam machine according to a second embodiment of the present invention. A duplicate description will be omitted.

The optical path shifter 20 is formed of a plate-shaped transparent body having two parallel surfaces, and is rotatable by a motor 22. The optical path shifter 20 is disposed between the mirror 3 and the mirror 5. The reference position of the optical path shifter 20 is a position where the laser light reflected by the mirror 3 is perpendicularly incident on the side surface of the optical path shifter 20. Note that, as in the first embodiment, f
lens 14 is positioned such that center axis S is perpendicular to the paper surface and deflection point H coincides with center Os of reflection surface 13a.

The operation of the laser beam machine according to the second embodiment configured as described above is as follows.

The control device 16 calculates the angle θy from the reference position of the reflection surface 5a based on the Y coordinate of the processing location described in the processing program, and calculates the angle θy from the reference position of the reflection surface 13a based on the X coordinate of the processing location. Is calculated.

Further, based on the obtained angle θy, the reflection surface 5
After determining the position Q on the reflecting surface 5a where the laser light reflected by the mirror 3 can be incident on the center Os, the rotation of the optical path shifter 20 that can cause the laser light reflected by the mirror 3 to be incident on the position Q The angle β is calculated or obtained from a table stored in advance. Then, the reflection surface 5a is set at an angle θ.
y, the reflection surface 13a has an angle θx, and the optical path shifter 20 has an angle β.
Then, the laser oscillator 1 is operated to emit laser light.

In this embodiment, since the optical path shifter 20 is a plate-shaped transparent body whose both surfaces are parallel, the reliability is high and the manufacture is easy.

In this embodiment, the optical path shifter 2
0 is disposed between the mirror 3 and the mirror 5, but the optical path shifter 20 may be disposed anywhere between the laser oscillator 1 and the mirror 13 (in practice, the optical path shifter 20 is disposed between the aperture 2 and the mirror 13). Therefore, the degree of freedom in design increases.

The optical path shift 20 need not be parallel on both sides. In this case, the incident light and the outgoing light are not parallel, but by rotating the optical path shifter, the transmitted light can be moved in parallel, as in the case where both surfaces are parallel.

FIG. 6 is a side view showing a configuration example of a laser beam machine according to a third embodiment of the present invention, in which the same reference numerals as those in FIGS. And a duplicate description will be omitted.

In this embodiment, the deflection point H of the fθ lens 14 is positioned at the center Of of the reflection surface 5a of the mirror 5. The optical path shifter 30 includes the mirror 5 and the mirror 13
And is located between. The optical path shifter 30 may be any one of the optical path shifter 7 and the optical path shifter 20 described above. The distance between the axis M and the axis N is L.

The operation of the laser beam machine according to the third embodiment thus configured is as follows.

The control device 16 calculates the angle θy from the reference position of the reflection surface 5a based on the Y coordinate of the processing location described in the processing program, and calculates the angle θy from the reference position of the reflection surface 13a based on the X coordinate of the processing location. Is calculated. Also,
Based on the obtained angle ε, the angle γ at which the optical axis of the laser beam reflected by the mirror 5 moves the optical path shifter 30 by Ltan2ε is calculated or obtained from a previously stored table. Then, the reflecting surface 5a is set to the angle θy,
After rotating a by an angle ε and the optical path shifter 30 by an angle γ, the laser oscillator 1 is operated to oscillate laser light.

Assuming that the optical path shifter 30 is not provided, the laser beam reflected by the mirror 5 viewed from the N-axis direction travels rightward in the figure and enters the reflection surface 13a as shown by a two-dot chain line in the figure. , The reflected light C from the N axis at an angle 2ε
Incident on. Here, when the reflected light C is traced back to the light source side, as shown by a dotted line in the figure, it becomes a laser beam output from a point Of1 Ltan2ε away from the point Of. Since the laser light output from the point Of1 does not pass through the polarization point H, the laser light transmitted through the fθ lens 14 is obliquely incident on the work 15 in the X direction.

On the other hand, in this embodiment, as shown by a solid line in FIG.
The laser beam reflected by the mirror 5 is parallel-shifted in the optical path by Ltan2ε and is incident on the reflection surface 13a. That is,
Since the laser light to be incident on the reflection surface 13a is the laser light passing through the point Of, that is, the deflection point H, the laser light transmitted through the fθ lens 14 is incident on the work 15 perpendicularly in the X direction. In addition, since the deflection point H coincides with the point Of of the reflection surface 5a, the laser light is applied to the work 1 in the Y direction.
5 is perpendicularly incident. Therefore, the axis of the processed hole becomes vertical.

[0045]

As described above, according to the present invention,
Since a transmission type optical path shifter that translates the laser light is provided between the light source and the fθ lens, control is performed so that all the laser light passes through the deflection point of the fθ lens while maintaining an angle determined by the processing position. can do. As a result, in the case of drilling, a hole perpendicular to the workpiece can be formed.

Further, the transmission type optical path shifter is made of two wedge-shaped transparent bodies or a plate-shaped transparent body whose both surfaces are parallel to each other. And the processing speed can be increased.

[Brief description of the drawings]

FIG. 1 is a plan view showing a configuration example of a laser beam machine according to a first embodiment of the present invention.

FIG. 2 is a side view showing a configuration example of the laser beam machine according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating a function of an optical path shifter.

FIG. 4 is a diagram illustrating an incident angle of a laser beam in a Y-axis direction incident on a work 15;

FIG. 5 is a plan view showing a configuration example of a laser beam machine according to a second embodiment of the present invention.

FIG. 6 is a side view showing a configuration example of a laser beam machine according to a third embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 5 mirror 5a reflection surface of mirror 5 7 optical path shifter 13 mirror 13a reflection surface of mirror 13 fθ lens Os center of reflection surface

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hiroyuki Sugawara 502 Kandachi-cho, Tsuchiura-shi, Ibaraki F-term in the Machinery Research Laboratory, Hitachi, Ltd. (Reference) 2H041 AA12 AB26 AC01 AZ02 AZ05 2H045 AB13 AB53 4E068 CA06 CB05 CD08 CD12 DA11

Claims (5)

[Claims] 1. A light source for oscillating laser light, a first mirror disposed on an optical axis of the laser light and capable of positioning an angle with respect to the optical axis around a rotation axis, and a rotation axis of the first mirror.
A second mirror disposed at a position twisted with respect to the rotation axis of the mirror, and capable of being positioned around the rotation axis, and an fθ lens for condensing the laser light deflected by the two mirrors. In the laser processing apparatus, a transmission type optical path shifter that translates the laser light is provided between the light source and the fθ lens. 2. The transmission type optical path shifter is disposed between the light source and the first mirror, and the optical axis of the laser light deflected by the first mirror is set at a predetermined point on the second mirror. The laser processing apparatus according to claim 1, wherein the transmission type optical path shifter is positioned so as to be incident on the laser beam. 3. The transmission type optical path shifter is disposed between the first mirror and the second mirror, and sets the optical axis of the laser light reflected by the first mirror to Ltan2ε.
(Where ε is the rotation angle of the second mirror, and L
2. The laser processing apparatus according to claim 1, wherein the transmission type optical path shifter is positioned so as to move (a distance between a rotation axis of the first mirror and a rotation axis of the second mirror). 3. . 4. The transmission-type optical path shifter is formed of two wedge-shaped transparent bodies having one apex angle facing the other bottom side and facing surfaces parallel to each other. The laser processing apparatus according to any one of claims 1 to 3, wherein 5. The laser processing apparatus according to claim 1, wherein the transmission type optical path shifter is formed of a plate-shaped transparent body having both surfaces formed in parallel.