JP2000347113A - Oscillation reflection mirror md laser beam machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oscillation reflection mirror which can be oscillated at a high speed and is capable of shortening an optical path when the mirror is disposed in the optical path. SOLUTION: The reflection mirror 4 has a centroild on the same axis as the axis of an oscillation shaft and oscillates around the oscillation shaft to reflect an incident laser beam on its reflection surface 40. In such a case, the reflection mirror has an elliptic outline part 41 along the outline of a reflection spot S of an elliptic shape with respect to the incident beam made incident at a prescribed incident angle and a straight outline part 42 parallel which is continuous with the elliptic outline part 41 and is parallel to the oscillation axis X at the external shape outline viewing the reflection surface 40 from the front.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oscillating reflection mirror and a laser processing machine disposed in an optical path of a laser processing machine, and more particularly, to punching a printed circuit board on which electronic circuit components such as ICs and LSIs are mounted. The present invention relates to a oscillating reflection mirror suitable for being disposed in the optical path of a laser processing machine for use and a laser processing machine using the same.

[0002]

2. Description of the Related Art As a laser beam machine for punching a printed circuit board on which electronic circuit components such as ICs and LSIs are mounted, a pulsed laser beam oscillated from a laser oscillator is reflected on an optical path of the laser beam. It is known that a plurality of holes are formed by being reflected by a mirror, guided to a condenser lens, and irradiated on a printed circuit board to be processed.

[0003] In recent years, as electronic circuit components have become higher in density and higher in integration, printed circuit boards on which they are mounted are required to have higher density and multilayer wiring patterns. Machining accuracy is required.

When a predetermined processing area of a printed circuit board is irradiated with a laser beam for processing, an XY table on which the printed circuit board is mounted is generally moved to an irradiation position. However, several tens of millimeters
To perform high-precision drilling such as
When the Y table is moved to perform positioning, the inertia of the XY table on which the printed circuit board is mounted has to be taken into account, so that there is a limit to the processing accuracy that can be obtained. For this reason, a laser processing machine that performs high-precision drilling tends to use an optical scanning laser processing machine that controls a focal position by scanning a reflection mirror of an optical system.

[0005] Such an optical scanning type laser beam machine is:
By arranging an oscillating reflection mirror oscillating around a vertical axis or a horizontal axis in the optical path and setting these at a predetermined angle,
The irradiation position is adjusted. As the oscillating reflection mirror to be used, a mirror whose outer contour is usually rectangular and parallel flat when viewed from the front is used.

[0006]

By the way, the above-mentioned oscillating reflection mirror arranged in the optical path of the laser beam machine usually has a four-dimensional reflection with respect to an incident laser beam emitted from a fixed position.
Although it is arranged so as to have an incident angle of 5 degrees, the reflection spot formed on the reflection surface has an elliptical shape. Therefore, when the above-mentioned reflection surface uses a oscillating reflection mirror having a rectangular shape, There are portions not involved in reflection at the four corners of the reflection surface. The presence of this portion causes an increase in the moment of inertia, which is not preferable in improving the swing speed.

On the other hand, in such a laser beam machine, it is desired to reduce the distance of the optical path as much as possible because it is necessary to suppress the output attenuation and the optical path error. Therefore, the oscillating reflection mirrors arranged in the optical path are also arranged close to each other. However, when a oscillating reflection mirror having a rectangular shape is used, since the four corners interfere with each other, there is a limit in reducing the arrangement interval. there were.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an oscillating reflection mirror and an oscillating reflection mirror which can be oscillated at a high speed and can be arranged at short intervals when arranged on the optical path. An object of the present invention is to provide a laser beam machine.

[0009]

In order to achieve the above object, the present invention has a center of gravity coaxial with an oscillating axis, oscillates around the oscillating axis and reflects an incident laser beam on a reflecting surface thereof. In the oscillating reflecting mirror, the first aspect is that the outer contour of the reflecting surface when viewed from the front has an elliptical contour along the contour of an elliptical reflection spot for a laser beam incident at a predetermined incident angle. The feature is.

Further, the present invention provides the oscillating reflection mirror having the first feature, wherein the oscillating reflection mirror has a linear contour portion continuous with the elliptical contour portion and parallel to the oscillating axis. And

Further, a laser beam machine according to the present invention is characterized in that a swing reflection mirror having the first or second feature is disposed in an optical path.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Note that the present invention is not limited to this embodiment.

FIG. 1 shows a laser beam machine according to an embodiment of the present invention. In FIG.
Denotes a laser processing machine, and P denotes a printed circuit board to be processed.

As shown in FIG. 1, a laser processing machine 1
Is a laser oscillator 2, a condenser lens 3 for irradiating the printed circuit board P with a laser beam oscillated from the laser oscillator 2, and an optical path L disposed between the laser oscillator 2 and the condenser lens 3 and arranged around a vertical axis. And two oscillating reflection mirrors 4 and 5 oscillating about a horizontal axis.

As the laser oscillator 2 and the condenser lens 3, those used in an optical scanning type laser beam machine equipped with two oscillating reflection mirrors are used.

Although not shown in the drawings, the XY table on which the printed circuit board P is mounted, various devices such as a drive system thereof, the main body frame and the like also have two oscillating reflection mirrors. This is a normal type used for an optical scanning type laser beam machine.

The above-mentioned oscillating reflection mirror 4 is bonded and fixed to a grip portion 60 (see FIG. 2) of the galvano driving device 6 which is disposed vertically, and has a center of gravity coaxial with a vertical oscillating axis X. Oscillate about the oscillating axis X to reflect the incident laser beam on the reflection surface 40 thereof.

As shown in FIG. 2A, the outer contour of the reflection surface 40 is 45 degrees when the reflection surface 40 is viewed from the front.
An elliptical contour portion 41 along the contour of the elliptical reflection spot S for the incident laser beam incident at an incident angle of degrees,
And a linear contour 42 continuous with the elliptical contour 41 and parallel to the swing axis X. Further, in the present embodiment, the oscillating reflection mirror 4 is configured by a parallel flat plate (FIG. 2B).

Oscillating reflection mirror 4 having the above-mentioned outer contour
Is an area that can cover the area of the reflection spot corresponding to the swing angle α (for example, −7 ° <α <7 °). That is, as shown in FIG. 3, the length of the major axis of the reflection spot when incident at the swing angle α is longer than the length of the major axis B of the reflection spot formed when incident at 45 °. Is also longer. Therefore, the distance (width) W between the linear contour portions 42
Is made longer than the maximum length of the long axis of the reflection spot when the light is incident at the swing angle α. Here, the major axis B 'of the reflection spot S when the swing angle is α is B' = 2r / (sin (45 ° -α)) where r is the beam radius of the incident laser beam.

The length Z of the linear contour portion 42 is determined by adjusting the position of the center of gravity of the oscillating reflection mirror 4 when the oscillating reflection mirror 4 is mounted on the grip portion 60 of the galvano driving device 6.
When the length of the minor axis C of the ellipse forming the outline 1 is 100, it is preferably 12 to 40 (for example, 3 to 10 mm when the minor axis C is 25 mm).

The thickness t of the oscillating reflection mirror 4 is preferably 1 mm to 7 mm, for example, 3 mm in order to obtain surface accuracy and material strength required for this type of oscillating reflection mirror.

The material of the oscillating reflection mirror 4 is a normal material of the oscillating reflection mirror conventionally used in an optical scanning laser beam machine for boring a printed circuit board, for example, a lightweight material such as silicon or beryllium. Use materials.

When attaching the swinging reflection mirror 4 to the holding portion 60 of the galvano drive device 6, the tip of the holding portion is
The ellipse forming the elliptical contour portion 41 is aligned and fixed so as to be in contact with the upper chord of the ellipse (the upper end of the minor axis C of the ellipse).

As shown in FIG. 1, the oscillating reflection mirror 5 is provided with a holding portion 7 of a galvano driving device 7 which is disposed horizontally.
0 (see FIG. 4), and the horizontal swing axis Y
And has a center of gravity on the same axis as the optical axis, swings around the swing axis Y, reflects the incident laser beam reflected by the swing reflecting mirror 4 on the reflecting surface 50 thereof, and guides the incident laser beam to the condenser lens 3. .

As shown in FIG. 4, similarly to the oscillating reflection mirror 4, the oscillating reflection mirror 5 has an outer contour of the reflection surface 50 of 45 degrees when the reflection surface 50 is viewed from the front. An elliptical contour 51 along the contour of an elliptical reflection spot for an incident laser beam incident at an incident angle, and a straight contour 52 continuous with the elliptical contour 51 and parallel to the oscillation axis X.
have.

In the case of the oscillating reflection mirror 5, as shown in FIG. 5, the distance from the oscillating reflection mirror 4 (the oscillating reflection mirrors 4 and 5 are set at 45 ° to the incident laser beam). The position of the incident laser beam is horizontal as shown by the dotted line in FIG. Since it is shifted in the direction, the area is set to include this laser beam. Specifically, the length D of the shaft is set to a length exceeding at least 2 (Rtan2α + r / cos (2α)).

The distance (width) between the straight contour portions 52
As in the case of the oscillating reflection mirror 4, W 'is made longer than the maximum length E' of the major axis of the reflection spot at the oscillating angle β as shown in FIG. Here, the major axis E ′ of the reflection spot S ′ when the swing angle of the swing reflection mirror 5 is β is E ′ = 2r / (sin (45 °), where r is the beam radius of the incident laser beam. −β)).

The thickness and material of the oscillating reflection mirror 5 are the same as those of the oscillating reflection mirror 4.

When the swing reflection mirror 5 is mounted on the grip 70 of the galvano drive device 7, the tip of the grip 70 is brought into contact with the upper chord of the ellipse forming the elliptical contour (the upper end of the axis D). 2) Align and fix.

The laser beam machine 1 according to the present embodiment has the reflecting surfaces 40, 5 on the oscillating reflecting mirrors 4, 5 disposed on the optical path L.
Since there are hardly any portions that are not involved in the reflection at the four corners of 50, the moment of inertia can be reduced accordingly. Therefore, the angle can be set at a high swing speed. In addition, since the rocking reflection mirrors 40 and 50 have linear contours 42 and 52 parallel to the rocking axes X and Y at both ends, the rocking reflection mirrors 4 and 5 are driven by galvano-type driving sources. Even when the optical axis L is attached to the gripping portions 60 and 70 of the driving devices 6 and 7 and is disposed in the optical path L, the positioning of the swing axes X and Y can be performed accurately and easily. Further, since there is almost no portion that is not involved in the reflection at the four corners as compared with the related art, the intervals between the oscillating reflection mirrors 4 and 5 can be reduced. Therefore, the optical path L itself can be shortened, and output attenuation, reduction of optical path errors, and downsizing of the processing machine can be achieved.

The outer contour of the reflecting surface of the oscillating reflecting mirror according to the present invention has an elliptical shape with respect to an incident laser beam incident at an incident angle of 45 degrees when the reflecting surface is viewed from the front as in the above embodiment. It is preferable to have a form having an elliptical contour portion along the contour of the reflection spot of the shape,
As long as the laser beam incident at 45 ° and the swing angle α can be covered, a form having an elliptical contour along the contour of the elliptical reflection spot with respect to the laser beam incident at another incident angle may be adopted.

In the above embodiment, the oscillating reflection mirror has a parallel flat reflecting surface. For example, the oscillating reflection mirror 8 shown in FIGS. 6A and 6B is used. The shape of the reflection surface 80 as viewed from the front is the same as that of the reflection mirror 4.
And a tapered surface symmetrical with respect to the oscillation axis (for example, the tapered surface 8 in FIG.
1, 82, 33) may be used in which the moment of inertia is further reduced without impairing the rigidity.

[0033]

According to the present invention, the following effects can be obtained.

According to the oscillating reflecting mirror having the first feature, high-speed oscillating is possible, and the optical path can be shortened when disposed on the optical path.

According to the oscillating reflection mirror having the second feature, when the oscillating reflection mirror is disposed in the optical path, the position of the oscillating shaft can be accurately and easily adjusted.

According to the laser processing machine having the above characteristics, it is possible to perform high-speed and high-precision drilling.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic configuration of an optical system in an embodiment of a laser beam machine according to the present invention.

FIGS. 2A and 2B are diagrams showing a form of a swing reflection mirror according to the embodiment, wherein FIG. 2A is a front view and FIG. 2B is a side view.

FIG. 3 is a schematic diagram showing a change in an optical path when the swing reflection mirror in the embodiment is swung.

FIGS. 4A and 4B are diagrams showing a form of the oscillating reflection mirror in the embodiment, wherein FIG. 4A is a front view and FIG. 4B is a side view.

FIG. 5 is a schematic diagram showing a change in an optical path when the swing reflection mirror in the embodiment is swung.

6A and 6B are diagrams showing another embodiment of the oscillating reflection mirror, wherein FIG. 6A is a rear view and FIG. 6B is a side view.

[Explanation of symbols]

1: laser processing machine, 4,5: swing reflection mirror, 40,
50: reflective surface, 41, 51: elliptical contour, 42, 52:
Linear contour, L: optical path, S, S ': reflection spot, X,
Y: swing axis.

Claims (3)

[Claims] 1. An oscillating reflecting mirror having a center of gravity coaxial with an oscillating axis, oscillating about the oscillating axis, and reflecting a laser beam on a reflecting surface thereof, wherein the reflecting surface is viewed from the front. An oscillating reflecting mirror, characterized in that the contour has an elliptical contour along the contour of an elliptical reflection spot for a laser beam incident at a predetermined incident angle. 2. The oscillating reflection mirror according to claim 1, wherein the oscillating reflection mirror has a straight contour part which is continuous with the elliptical contour part and parallel to the oscillating axis. 3. A laser beam machine comprising the swing reflection mirror according to claim 1 disposed in an optical path.