JP2002148562A - Semiconductor laser processing equipment - Google Patents

Abstract

(57) Abstract: A high-intensity laser beam is obtained by using a plurality of flat-plate laser units each having an LD array in which a large number of laser diodes are arranged in a bar shape. SOLUTION: An LD unit stack 3a, 3b in which a plurality of flat LD units 1 each having an LD array 2 in which a large number of laser diode elements are arranged in a bar in the slow axis direction is provided.
a, a collimator lens 4 for setting the width of the laser beam emitted from the flat LD unit 1 in the fast axis direction equal to or less than the thickness of the flat LD unit and the width in the slow axis direction equal to the length of the LD array in front of the flat LD unit 1; And a PBS adder 14 including a λ / 2 wavelength plate 12 and a deflection beam splitter 13 for halving the laser beams emitted from the collimator lenses 4 and 5 in the SLOW direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser processing apparatus, and more particularly to a laser beam having a high brightness, that is, a high laser power density by using a plurality of flat laser units having an LD array in which laser diode elements are arranged in a bar shape. The present invention relates to a semiconductor laser processing apparatus for obtaining the above.

[0002]

2. Description of the Related Art Conventionally, a CO ₂ laser or a YAG laser has been used in a laser processing apparatus for precision welding and cutting of metals because it is necessary to obtain a high laser power density. That is, since a CO ₂ laser or a YAG laser can obtain a high-output laser and can easily narrow a laser beam diameter with a condenser lens system, a laser of about 1 MW / cm ² required for precision welding or the like. Power density is obtained.

On the other hand, a semiconductor laser processing apparatus has a simple structure, is compact, and is low in cost. However, since the output of a single laser diode element is small, it is necessary to use a large number of semiconductor lasers to obtain a large output. Therefore, a flat LD unit having an LD array in which a large number of laser diode elements are arranged in a bar shape in the slow axis direction has been developed. For example, thickness 1 μm, width 100 μm
A 10 mm long LD array formed by arranging 35 to 70 laser diode elements in a bar shape is assembled together with its cooling means into a 1.8 mm thick, 12.5 mm wide, 18 mm long housing. A flat LD unit having an output of 40 to 200 W is known.

[0004]

By the way, the above CO ₂
A laser processing device using a laser or a YAG laser has a problem that the device configuration is complicated, large, and costly. Therefore, it is difficult to obtain a required laser power density using a simple and compact semiconductor laser. Is desired.

Therefore, it is conceivable to construct an LD unit stack by stacking and disposing a plurality of the above-mentioned flat LD units, collimating the output laser beam with a collimator lens, and reducing the laser beam diameter with a condenser lens system. However, even if the laser beam emitted from the laser diode element is focused by the lens optical system, there is a limit that it cannot be focused to less than 1/3 in the slow axis direction in principle due to the characteristics of the lens. Therefore, there is a problem that a laser beam of 10 mm in the slow axis direction can be focused only to a maximum of about 3 mm, and a sufficient laser power density cannot be obtained.

[0006] A deflection beam splitter (hereinafter referred to as PB)
An adder is known which adds two laser beams whose deflection directions are orthogonal to each other by using a laser beam from a pair of LD unit stacks whose deflection directions are orthogonal. Although it is conceivable to double the density, the laser beam width in the slow axis direction is the same, and a sufficient laser power density cannot be obtained due to the above focusing limit, and the above problem cannot be solved.

Also, US Pat. No. 5,557,475 describes that, like a laser beam from a flat LD unit,
Means is disclosed in which a laser beam that is horizontally long in the slow axis direction is divided in the longitudinal direction and vertically overlapped to obtain a laser beam having luminance symmetrical in the vertical and horizontal directions, but this does not increase the laser power density.

In view of the above-mentioned conventional problems, the present invention provides a semiconductor laser processing apparatus capable of obtaining a high-intensity laser beam by using a plurality of flat laser units having an LD array in which laser diode elements are arranged in a bar shape. It is intended to provide.

[0009]

According to the present invention, there is provided a semiconductor laser processing apparatus comprising: a flat LD unit having an LD array in which laser diode elements are provided in a bar shape in a slow axis direction; and a stack of the flat LD units. LD
The unit stack and the width of the laser beam emitted from each flat LD unit in the fast axis direction
The width in the slow axis direction is equal to or less than the thickness of the D unit.
A collimator lens provided at the front of the LD unit stack so as to be equal to the array length, and a PBS adder that makes a laser beam emitted from the collimator lens half the width in the slow axis direction are provided. The laser beam having a rectangular cross section emitted from the LD unit stack via the collimator lens can be divided into two in the slow axis direction and added to each other, so that the laser power density (brightness) can be doubled and simultaneously the laser power density in the slow axis direction can be increased. The laser beam width can be halved to improve the light condensing property in the slow axis direction, which is very effective in improving the laser power density.

The PBS adder preferably comprises a λ / 2 wavelength plate and a deflection beam splitter.

Further, when a cylindrical lens for expanding the laser beam emitted from the PBS adder in the slow axis direction and a condensing lens system for condensing the laser beam emitted from the cylindrical lens are provided, the magnification of the cylindrical lens can be increased. As X, the maximum light collection rate with respect to the width in the slow axis direction of the laser beam emitted from the PBS adder by the light collection lens system is 3X times, and the light collection property can be further improved by expanding in the slow axis direction with a cylindrical lens. The laser power density can be improved.

[0012] Further, it has an optical fiber for making the laser beam condensed by the condensing lens system incident on one end, and an objective lens system provided on the other end of the optical fiber. When it is set to 0.2 to 0.25, the focused laser beam can be made incident on the optical fiber without loss, propagated through the optical fiber, and irradiated with the laser beam in an arbitrary position and direction by the objective lens system. In addition, a laser processing apparatus having a compact configuration and good workability can be realized.

A plurality of LD unit stacks are provided,
The width of the laser beam emitted from each flat LD unit in the fast axis direction is set to a value obtained by dividing the thickness of the flat LD unit by the number of LD unit stacks provided by a collimator lens, and the collimator lens from each LD unit stack is used. Laser beam emitted from a plurality of LD unit stacks is superimposed on the laser beam emitted from a single LD unit stack by interleaving the laser beams emitted from the plurality of LD unit stacks. Can be added to a laser beam having the same cross section as that described above, and the laser power density can be improved a plurality of times.

Further, the semiconductor laser processing apparatus of the present invention
A flat LD unit having an LD array in which laser diode elements are provided in a bar shape in the slow axis direction, a plurality of LD unit stacks provided by stacking the flat LD units, and a laser beam emitted from each flat LD unit The width in the fast axis direction of the
A collimator lens provided at the front of the LD unit stack for equalizing the thickness of the unit by the number of the LD unit stacks and making the width in the slow axis direction equal to the length of the LD array, and a collimator from each LD unit stack A laser beam emitted from a plurality of LD unit stacks is interleaved with a single LD unit stack by using a laser beam emitted from a plurality of LD unit stacks. Can be added to the laser beam having the same cross section as the laser beam from the laser beam, and the laser power density can be improved a plurality of times.

In the interleave adder, plate-like prisms having a thickness equal to or greater than the width in the fast axis direction of the laser beam emitted from each collimator lens are stacked and arranged, and this plate-like prism is emitted from each LD unit stack. Those that reflect or transmit a laser beam are preferable.

In the interleave adder, if an auxiliary glass is interposed in a gap between the incident end face and the output end face of the laser beam and the incident end face, the output end face and the internal reflection end face are polished, the incident end face of the laser beam In this way, it is possible to prevent the flat prism from vibrating in the gap at the time of polishing the emission end face and to generate minute chips in the glass, thereby preventing the laser beam from being diffused due to the chips and causing energy loss.

The laser beam reflecting surface of the interleave adder preferably reflects the laser beam totally. That is, the interleave adder is configured by combining, for example, a square prism and a rhombus or a square prism and a right-angled triangular plate prism according to the arrangement of a plurality of LD unit stacks. Any shape that reflects light may be used.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a semiconductor laser processing apparatus according to the present invention will be described below with reference to FIGS.

1 and 2, reference numeral 1 denotes a flat LD unit having an LD array 2 in which a large number of laser diode elements are arranged in a bar shape in the slow axis direction. For example, a laser diode having a thickness of 1 μm and a width of 100 μm is provided. A 10 mm long L formed by arranging 35 to 70 elements in a bar shape
D array 2 together with its cooling means is 1.8 mm thick,
It is configured by being incorporated in a housing having a width of 12.5 mm and a length of 18 mm. This flat LD unit 1 has 40 to 20
It has an output of 0W.

Reference numerals 3a and 3b denote a pair of LD unit stacks in which a plurality of flat LD units 1 are stacked. In the present embodiment, one LD unit stack 3a in which six flat LD units 1 are stacked and 5 The other LD unit stack 3b, in which the two flat LD units 1 are stacked, is arranged in parallel in a plan view so that the laser beams are parallel to each other, and vertically in half so that the flat LD units 1 are staggered in a side view. They are arranged with a pitch shift.

At the front of the LD unit stacks 3a and 3b, a laser beam emitted from the LD array 2 is converted into a parallel beam having a width half the thickness of the flat LD unit 1 in the fast axis direction. A collimator lens 4 and a slow-axis collimator lens 5 for converting the laser beam emitted from the LD array 2 into parallel light having a width substantially equal to the length of the LD array 2 in the slow axis direction are provided. With these collimator lenses 4 and 5,
As shown in FIG. 4 (a), in the above specific example, six and five laser beams 6 each having a vertical width of 0.9 mm in the fast axis direction and a horizontal width of 10 mm in the slow axis direction are 1.
Two laser beam groups 7a and 7b are formed at a pitch of 8 mm and shifted by half a pitch from each other and arranged in a staggered manner.

At the front of the collimator lenses 4 and 5, an interleave adder 8 for converting the laser beam groups 7a and 7b into a single rectangular cross-section laser beam 11 as shown in FIG. Have been. As shown in FIG. 3, the interleave adder 8 alternates between six square plate-like prisms 9 and five rhombic plate-like prisms 10 having the same thickness as the width of each laser beam 6 in the fast axis direction. The laser beam 6 of the laser beam group 7a travels straight and passes through the laser beam group 7a, and the laser beam 6 of the laser beam group 7b moves in parallel by two perpendicular total reflections. A laser beam 11 having a single rectangular cross section is formed by entering between the laser beams 6 and filling the gap. This laser beam 11
In the above specific example, the cross section has a substantially square cross section with a vertical length of 9.9 mm and a horizontal width of 10 mm.

At the front of the interleave adder 8, the laser beam 11 is divided into two in the slow axis direction and added to each other, and the laser beam 15 having a half width of the laser beam 11 and twice the laser power density (brightness) is provided. Is provided with a λ / 2 wavelength plate 12 and a PBS adder 14 composed of a pair of deflection beam splitters (hereinafter, referred to as PBS) 13a and 13b. The PBS 13a facing the λ / 2 wavelength plate 12 may be replaced with a reflecting means such as a prism that totally reflects the laser beam at right angles. In the PBS adder 14, the laser beam 11 is divided into two in the slow axis direction, and one half of the laser beam 11 is converted into a PB after the deflection direction of the laser beam 11 is changed by 90 degrees by the λ / 2 wave plate 12.
In S13a, the light is totally reflected at a right angle and enters the PBS 13b,
The other half goes straight while maintaining the original deflection direction and
b, the laser beam 11 is totally reflected at right angles by the PBS 13b, and passes through the other half as it is, so that the laser beam 11 is divided into two in the slow axis direction and added together, and as shown in FIG. As shown, in the above specific example, a half-width double-density laser beam 15 having a vertical dimension of 9.9 mm and a width dimension of 5 mm is formed.

At the front of the PBS adder 14, a plano-concave cylindrical lens 16 and a condenser lens system 17 for multiplying the width of the half-width double-density laser beam 15 in the SLOW direction by X (X> 1) are arranged. . The reason for providing the plano-concave cylindrical lens 16 is as follows. When the laser beam 15 is condensed in the slow axis direction, as shown in FIG. 5A, the width W of the laser beam 15 is converged to 1/3 due to the properties of the lens used in the condensing lens system 17. Is the limit,
The laser beam width y at the time of focusing is limited to y = 1/3 W. In the above specific example, the laser beam can be focused only up to 5/3 mm, and a sufficient laser power density cannot be obtained. On the other hand, as shown in FIG. 5B, the width W of the laser beam 15 is multiplied by X, and as shown in FIG. When formed, the light can be condensed to a maximum of y = (） X) · W by the condensing lens system 17 having a high light-condensing magnification. Light can be collected up to 5 / 10.5 = 0.48 mm. Thus, in the above-mentioned specific example, the half-width double-density laser beam 15 can be converged by the plano-concave cylindrical lens 16 and the condensing lens system 17 to a width of 0.37 × a height of 0.27 mm.

The half-width double-density laser beam 15 can be regarded as a collimated light in the fast axis direction and has a good light-collecting property. You don't have to.

The laser beam thus collected is incident on an optical fiber 19 provided with an objective lens system 20 at the other end. Therefore, the condenser lens system 17 is
NA of optical fiber 19 (= sin θ) = 0.2 to 0.2
A converging lens having a focal length and an outer diameter of 5 is selected. In the above specific example, 0.37 × 0.
Since the light is converged at 27 mm, the optical fiber 19 having a diameter of 0.5 mm can be used.

Thus, in the above example, the output is 100
When the W-shaped flat LD unit 1 is used, the total output is 1.
At 1 KW, the cross-sectional area of the optical fiber 19 is 0.196 mm ²
Therefore, the laser power density becomes 561 KW / cm ² , and 1 MW / cm ² can be realized by reducing the focusing area by half with the objective lens system 20.
Precision laser welding and cutting can be realized using the D unit 1.

In order to perform such semiconductor laser processing, a control unit (not shown) for controlling the output of the LD array 2 of each flat LD unit 1 in the LD unit stacks 3a and 3b and controlling the movement of the objective lens system 20. Are provided.

According to this embodiment, a pair of LD unit stacks 3a and 3b are provided, and each LD unit stack 3
a, the fast-axis collimator lens 4 disposed at the front of the 3b is configured such that the width of the laser beam emitted from each LD unit 1 in the FAST direction is half the thickness of the LD unit 1, Since the laser beam groups 7a and 7b output from the LD unit stacks 3a and 3b via the collimator lenses 4 and 5 are provided with an interleave adder 8 that converts the laser beams 11 into a single rectangular cross section, a plurality of LDs are provided. The laser beams from the unit stacks 3a and 3b are combined into a single LD unit stack 3a,
It can be added to the laser beam of the same cross section as the laser beam from 3b, and the laser power density can be improved a plurality of times.

The laser beam 11 having a rectangular cross section emitted from the interleave adder 8 is input to the PBS adder 1.
4, the laser power density can be doubled and the laser beam density in the slow axis direction can be halved to improve the light condensing property in the slow axis direction. It has a great effect on improving laser power density.

The half-width double-density laser beam 15 emitted from the PBS adder 14 is temporarily X-folded in the slow axis direction by a plano-concave cylindrical lens 16 and a condenser lens system 17 which expand in the slow axis direction. By condensing after enlarging, the maximum condensing rate with respect to the width in the slow axis direction of the half-width double-density laser beam 15 by the condensing lens system 17 becomes 3X times, so that the condensing property can be further improved and the laser power density can be improved. can do.

The condensed laser beam is made incident on one end of an optical fiber 19 provided with an objective lens system 20 at the other end, and the condensing lens system 17 has an NA of 0.2 to 0.25. When a condensing lens having an appropriate focal length and outer diameter is used, the condensed laser beam is made incident on the optical fiber 19 without loss, propagates through the optical fiber 19, and the laser beam is directed to an arbitrary position and direction by the objective lens system 20. A laser processing apparatus which can irradiate a beam and has good workability with a compact configuration can be realized.

In the above embodiment, an example is shown in which two LD unit stacks 3a and 3b are arranged in parallel.
As shown in FIG. 6A, the two LD unit stacks 3a and 3b may be arranged orthogonally so that the emitted laser beams intersect at the interleave adder 8. In this case, the interleave adder 8 may be configured by stacking the square plate-like prism 9 and the triangular plate-like prism 21 as shown in FIG.

In the above embodiment, two LD unit stacks 3a and 3b are provided.
As shown in (a), three LD unit stacks 3
a, 3b, and 3c may be arranged orthogonally so that the emitted laser beams intersect at the interleave adder 8. In this case, as shown in FIG. 7B, the interleave adder 8 includes one square plate-like prism 9 having a thickness of 1/3 of the thickness of the plate-like LD unit 1 and two triangular plate-like prisms. The prisms 21 may be stacked and configured. Also, F
The AST direction collimator lens 4 is configured to convert the laser beam from the flat LD unit 1 into collimated light having a width in the FAST direction of 1/3 of the thickness of the flat LD unit 1. The shape of the flat prism may be any shape as long as the reflection surface can totally reflect the laser beam.

In the interleave adder 8 in the above embodiment, as shown in FIG. 3, the glass plates are stacked without gaps at the portions of the square and rhombic flat plate prisms 9 and 10 facing the laser beam emission end faces. However, the portion facing the incident end face protrudes in a cantilever shape with a gap corresponding to the thickness between the glass plates, and when the laser beam incident end face is polished, microscopic chipping occurs due to vibration of the glass plate However, the chipping causes the laser beam to diffuse and causes a reduction in energy efficiency.

Therefore, as shown in FIG. 8A, a square plate-like prism 9 is connected to both LD unit stacks 3a,
As shown in FIG. 8B, instead of the rectangular plate-like prism 22 having a length of 3b, as shown in FIG.
8A, an auxiliary glass plate 23 is arranged at a portion facing the LD unit stack 3a, and as shown in FIG. 8C, the auxiliary glass plates 23 are stacked and the areas of the incident end face and the exit end face of the laser beam indicated by oblique lines are shaded. Preferably, the interleaved adder 8 is polished and provided with an anti-reflection coating. Thereby, it is possible to eliminate the minute chipping of the glass at the time of polishing and to prevent reflection.
The laser beams from a and 3b can be added without energy loss. The rectangular flat prism 22
Rather than using, a square plate-like prism 9 and a square or triangular auxiliary glass plate 23 may be used in combination.

The two LD unit stacks 3a, 3b
6 are arranged as shown in FIG. 6, as shown in FIG. 9A, the square plate-like prism 9 is left as it is, and as shown in FIG. An auxiliary glass plate 23 is disposed at a portion facing the LD unit stack 3a, and as shown in FIG. 8C, these are stacked and polished on three side surfaces, which are the incident end surface and the emission end surface of the laser beam shown by oblique lines. , An anti-reflection coating. Further, when three LD unit stacks 3a, 3b and 3c are arranged as shown in FIG. 7, similarly, the auxiliary glass plate 23 may be arranged on the triangular flat prism 21.

[0038]

According to the semiconductor laser processing apparatus of the present invention, an LD unit stack in which a plurality of flat LD units are stacked as described above, a collimator lens provided at the front of the LD unit stack, and the collimator lens And a PBS adder for halving the laser beam emitted from the LD in the slow axis direction, so that the laser beam having a rectangular cross section emitted from the LD unit stack via the collimator lens is divided into two in the slow axis direction. Can be added to each other, resulting in a laser power density of 2
At the same time, the laser beam width in the slow axis direction can be halved to improve the light condensing property in the slow axis direction, which is very effective in improving the laser power density.

When a cylindrical lens for expanding the laser beam emitted from the PBS adder in the SLOW direction and a condensing lens system for condensing the laser beam are provided,
The light condensing property can be further improved by enlarging the cylindrical lens in the slow axis direction, and the laser power density can be improved.

The optical system further includes an optical fiber for allowing the laser beam condensed by the condenser lens system to be incident on one end, and an objective lens system provided on the other end of the optical fiber. When it is set to 0.2 to 0.25, the focused laser beam can be made incident on the optical fiber without loss, propagated through the optical fiber, and irradiated with the laser beam in an arbitrary position and direction by the objective lens system. In addition, a laser processing apparatus having a compact configuration and good workability can be realized.

A plurality of LD unit stacks are provided,
The width of the laser beam emitted from each flat LD unit in the fast axis direction is set to a value obtained by dividing the thickness of the flat LD unit by the number of LD unit stacks provided by a collimator lens, and the collimator lens from each LD unit stack is used. Laser beam emitted from a plurality of LD unit stacks can be added to form a single rectangular cross-section by superposing laser beams emitted from the laser unit stack, thereby increasing the laser power density by a factor of two or more. .

According to another semiconductor laser processing apparatus of the present invention, a flat LD unit having an LD array in which laser diode elements are provided in a bar shape in the slow axis direction, and the flat LD units are provided by stacking. The plurality of LD unit stacks, and the width of the laser beam emitted from each flat LD unit in the fast axis direction,
A value obtained by dividing the thickness of the flat LD unit by the number of the LD unit stacks, a collimator lens provided at the front of the LD unit stack to make the width in the slow axis direction equal to the length of the LD array, and each LD unit The laser beam emitted from the stack via the collimator lens is superimposed to form a single rectangular cross-section, so that an interleave adder is provided. The laser beam having the same cross section as the laser beam from the stack can be added to the laser beam, and the laser power density can be improved multiple times.

Further, if the interleave adder has an auxiliary glass interposed in the gap between the incident end face and the outgoing end face of the laser beam, and the incident end face, the outgoing end face and the internal reflection end face are polished, At the time of polishing the end face and the emission end face, it is possible to prevent the flat prism from vibrating in the gap to generate a minute chip in the glass, and to prevent the laser beam from being diffused by the chip and energy loss.

[Brief description of the drawings]

FIG. 1 is a plan view showing a schematic configuration of an embodiment of a semiconductor laser processing apparatus of the present invention.

FIG. 2 is a front view showing a schematic configuration of the embodiment.

3A and 3B show a configuration of an interleave adder according to the first embodiment, wherein FIG. 3A is an exploded perspective view and FIG. 3B is a side view.

FIG. 4 is a diagram showing a cross-sectional shape of a laser beam at each position in the embodiment.

5A and 5B are diagrams illustrating a light collecting limit in a slow axis direction by a light collecting lens system. FIG. 5A is an explanatory diagram of a light collecting state in a case where the light is not enlarged, and FIG.

6A and 6B show an arrangement state of an LD unit stack according to another embodiment of the present invention, wherein FIG. 6A is a plan view and FIG. 6B is an explanatory view of a flat prism constituting the interleaved adder.

FIG. 7 shows an arrangement state of an LD unit stack according to still another embodiment of the present invention, wherein (a) is a plan view,
FIG. 2B is an explanatory view of a flat prism constituting the interleave adder.

FIG. 8 is an explanatory diagram of an improved configuration of an interleave adder in the semiconductor laser processing apparatus of FIG. 1;

9 is an explanatory diagram of an improved configuration of an interleave adder in the semiconductor laser processing device of FIG.

[Explanation of symbols]

 Reference Signs List 1 flat LD unit 2 LD array 3a, 3b LD unit stack 4 fast axis collimator lens 5 slow axis collimator lens 8 interleave adder 9 square flat prism 10 rhombic flat prism 12 λ / 2 wavelength plate 13 deflection Beam splitter 14 PBS adder 16 Plano-concave cylindrical lens 17 Condensing lens system 19 Optical fiber 20 Objective lens system 21 Triangular plate prism 22 Rectangular plate prism 23 Auxiliary glass plate

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 2H037 AA04 BA03 BA05 BA06 CA11 CA17 CA21 CA39 2H099 AA17 BA17 CA06 CA08 4E068 CA02 CD08 CD09 CD13 CE08 CK01 5F073 AB27 AB28 AB29 BA09 EA15 EA22 EA24 FA26

Claims (9)

[Claims] 1. A flat LD unit having an LD array in which laser diode elements are provided in a bar shape in a slow axis direction, an LD unit stack provided by stacking the flat LD units, and emission from each flat LD unit A collimator lens provided at the front of the LD unit stack so that the width of the laser beam in the fast axis direction is equal to or less than the thickness of the flat LD unit, and the width in the slow axis direction is equal to the length of the LD array; And a PBS adder for reducing a laser beam emitted from the laser beam to a half width in the slow axis direction. 2. The semiconductor laser processing apparatus according to claim 1, wherein the PBS adder comprises a λ / 2 wavelength plate and a deflection beam splitter. 3. A system according to claim 1, further comprising a cylindrical lens for expanding a laser beam emitted from the PBS adder in a slow axis direction, and a condensing lens system for condensing the laser beam emitted from the cylindrical lens. 3. The semiconductor laser processing apparatus according to 1 or 2. 4. An optical fiber for making a laser beam condensed by a condenser lens system incident on one end, and an objective lens system provided on the other end of the optical fiber, wherein the NA of the condenser lens system is zero. 4. The semiconductor laser processing apparatus according to claim 3, wherein the value is 0.2 to 0.25. 5. A plurality of LD unit stacks are provided, and the width of the laser beam emitted from each flat LD unit in the fast axis direction is determined by the collimator lens so that the thickness of the flat LD unit is determined by the number of the LD unit stacks. 5. An interleave adder having a value obtained by dividing the laser beam emitted from each LD unit stack via a collimator lens to form a single rectangular cross section is provided. The semiconductor laser processing apparatus as described in the above. 6. A flat LD unit having an LD array in which laser diode elements are provided in a bar shape in the slow axis direction, a plurality of LD unit stacks provided by stacking the flat LD units, and each flat LD unit LD unit stack that makes the width in the fast axis direction of the laser beam emitted from the LD divided by the number of the LD unit stacks divided by the thickness of the flat LD unit, and makes the width in the slow axis direction equal to the length of the LD array. And a collimator lens provided at the front of the laser unit and an interleave adder for superimposing a laser beam emitted from each LD unit stack via the collimator lens to form a single rectangular section. . 7. The interleave adder stacks and arranges plate-like prisms having a thickness equal to or greater than the width in the fast axis direction of the laser beam emitted from each collimator lens, and the plate-like prism emits from each LD unit stack. 7. The semiconductor laser processing apparatus according to claim 5, wherein the laser beam is reflected or transmitted. 8. An interleave adder interposes an auxiliary glass in a gap between an incident end face and an outgoing end face of a laser beam,
8. The semiconductor laser processing apparatus according to claim 7, wherein the incident end face, the output end face, and the internal reflection end face are polished. 9. The semiconductor laser processing apparatus according to claim 7, wherein the laser beam reflecting surface of the interleave adder totally reflects the laser beam.