JP2001284730A - Condensing laser device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a condensing property even if a semiconductor laser unit where an array semiconductor laser is set to multiple stages is collimated for condensing by a condensing optical system regarding a condensing laser device that condenses the beam of a semiconductor laser with high density for applying to laser machining or the like. SOLUTION: In this condensing laser device that is equipped with a semiconductor laser unit 1 where a plurality of stages of array semiconductor lasers are overlapped, and a collimate optical system 2 that collimates a laser beam from the unit 1 to a group of parallel beams, a first beam group 10-1 is moved in parallel by a first prism 3 that inclines a beam direction to the first beam group 10-1 that is approximately half the group of parallel beams, and a second prism 4 that returns the beam direction to an original position again, thus obtaining a group 11 of composite parallel beams where two stages of the first beam group 10-1 are overlapped to a second beam group 10-2 of the remainder of the group of parallel beams in a direction orthogonally crossing an active layer stripe, and hence improving the condensing property.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a condensing laser device for condensing a semiconductor laser beam at a high density and applying it to laser processing or the like.

[0002]

2. Description of the Related Art Semiconductor lasers are characterized by high efficiency of converting electric energy into light energy and small size, but each semiconductor laser has a small output and uses an array semiconductor laser comprising a plurality of active layer stripes. To increase the output. For example, there is an array semiconductor laser in which several tens of active layer stripes are arrayed to obtain an output of about several tens of watts. Furthermore, a unit that has a high output of several hundred watts as a semiconductor laser unit by stacking array semiconductor lasers in several or more stages has been put to practical use.

It is important for an array semiconductor laser to focus a large number of laser beams from an active layer stripe on a minute spot. This is to obtain a high energy density at the processing point in the processing application, and it is necessary to focus on a minute spot to excite a solid-state laser such as YAG at the end face. In order to focus the array semiconductor laser, a collimating optical system for collimating the laser light from each active layer stripe into a group of parallel light beams is required. The collimating optical system is disclosed in, for example, JP-A-7-43643. The collimated parallel light beam is condensed by a condensing optical system such as a condensing lens.

In order to focus a semiconductor laser unit in which arrayed semiconductor lasers are stacked in multiple stages, laser light from each active layer stripe is collimated into a group of parallel light beams and focused by a focusing optical system. However, the shape of one active layer stripe is linear, for example, 100 μm in width and 1 μm in thickness.
m, and 40 active layer stripes form an array at 250 μm intervals in the active layer stripe direction, and the entire width is 10 mm.

Therefore, the light source is large in the width direction which is the direction of the active layer stripe. The thickness of the active layer stripe is 1 μm
The light source is small compared to the width direction even if it is stacked in multiple stages. For this reason, the condensed light spot which is collimated and condensed also becomes ten times or more larger in the width direction than in the thickness direction. For example, a unit with 10 layers of arrays is NA 0.2
When the light is condensed by the condensing optical system described above, the converged spot shape has a width of about 2 mm and a thickness of about 100 μm.

[0006] As described above, the poor ratio of the width to the thickness of the condensed spot, which is 10 times or more, deteriorates the processing quality in the processing application, and makes it difficult to perform uniform excitation in the end face excitation of a solid-state laser. .

[0007]

As described above, when a semiconductor laser unit in which arrayed semiconductor lasers are stacked in multiple stages is collimated and condensed by a condensing optical system, the light condensed in the width direction is compared with the thickness direction. Poor performance, for example, the ratio of the width to the thickness of the condensed spot is 10 times or more, and poor condensing property is an obstacle in many applications such as laser processing and excitation of a solid-state laser.

SUMMARY OF THE INVENTION An object of the present invention is to provide a condensing laser device having good condensing properties even when a semiconductor laser unit in which arrayed semiconductor lasers are stacked in multiple stages is collimated and condensed by a condensing optical system. .

[0009]

SUMMARY OF THE INVENTION In order to solve this problem, the present invention provides a semiconductor laser unit in which an array semiconductor laser comprising a plurality of active layer stripes is stacked in a plurality of stages, and a laser beam from each active layer stripe. A first collimating optical system for collimating the parallel light beam, and a condensing optical system for condensing the parallel light beam, wherein a first light beam direction is inclined with respect to about half of the first light beam group of the parallel light beam. The first light beam group is translated by a prism and a second prism that returns the direction of the light beam again, and the remaining second light beam of the parallel light beam group is moved.
The first parallel light beam group is a composite parallel light beam group in which the first light beam group overlaps the active layer stripe in two directions in a direction orthogonal to the light beam group.

The present invention also provides a semiconductor laser unit having a plurality of arrayed semiconductor lasers comprising a plurality of active layer stripes, a collimating optical system for collimating each laser beam from each active layer stripe into a group of parallel light beams, A first prism which tilts the light beam direction with respect to the first light beam group which is about half of the parallel light beam beam, and a second prism which restores the light beam direction again The first prism group translates the first ray group in parallel with the active layer stripe by the prism, and the third prism tilts the ray direction with respect to the remaining second ray group of the parallel ray group. The first light group and the second light group are orthogonal to the active layer stripe by moving the second light group in a direction orthogonal to the active layer stripe by a fourth prism returning to Are two-tiered in direction is obtained by such a composite collimated light ray group.

As a result, the light-collecting property in the direction of the stripe of the active layer is improved, and a light-collecting laser device which is highly practical for processing applications can be obtained.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the first aspect of the present invention, there is provided a semiconductor laser unit in which an array semiconductor laser comprising a plurality of active layer stripes is superposed on a plurality of stages, A collimating optical system that collimates each laser beam into a parallel light beam group and a focusing laser device that has a focusing optical system that focuses the parallel light beam group. The first light beam group is translated by a first prism that tilts the light beam direction and a second prism that restores the light beam direction again, and the first light beam is moved with respect to the remaining second light beam group of the parallel light beam group. A condensing laser device wherein the group is a composite parallel light beam group in which the group is superimposed in two steps in the direction orthogonal to the active layer stripe, wherein the size of the light source in the direction of the active layer stripe is reduced by half. It has the effect of improving the light harvesting by doubling the size of the direction of the light source.

According to a second aspect of the present invention, there is provided a semiconductor laser unit in which an array semiconductor laser comprising a plurality of active layer stripes is superposed on a plurality of stages, and each laser beam from each of the active layer stripes of the unit is converted into a parallel beam group. A collimating optical system for collimating the collimated light beam, and a converging optical system for condensing the parallel light beam group, wherein a first light beam direction is inclined with respect to about half of the first light beam group of the parallel light beam group. The first light group is translated in parallel with the active layer stripe by a prism and a second prism that restores the light direction again, and the light direction is changed with respect to the remaining second light group of the parallel light group. The second prism group is translated in a direction perpendicular to the active layer stripes by a third prism that is tilted and a fourth prism that returns the direction of the light beam to the original direction, thereby obtaining the first prism. Is the line group and the second group of light beams are two-tiered in the orthogonal direction to the active layer stripe, a focused laser device characterized by a composite collimated beam group,
By reducing the size of the light source in the active layer stripe direction by half and doubling the size of the light source in the orthogonal direction, the light collecting property is improved.

According to a third aspect of the present invention, in the converging laser device according to the first or second aspect, the width of the composite parallel light beam group in the direction of the active layer stripe and the height in the orthogonal direction are approximately equal to each other. A condensing laser device characterized by having a shaping optical system consisting of a cylindrical optical element.The beam shape of the complex parallel rays approaches a square, and the condensing optical system is effectively used to improve the condensing property. Is increased.

Further, as in the invention according to claim 4, in the condensing laser device according to claim 3, it is preferable that the cylindrical optical element is a cylindrical lens.

According to a fifth aspect of the present invention, in the converging laser device according to the first or second aspect,
It is preferable to use a condensing laser device in which the collimating optical system comprises an array of cylindrical lenses.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG.

(Embodiment 1) FIGS. 1A and 1B are schematic views showing the configuration of a condensing laser device according to the present embodiment, wherein FIG. 1A is a plan view and FIG. 1B is a side view. In FIG. 1, reference numeral 1 denotes a semiconductor laser unit in which a plurality of arrayed semiconductor lasers are stacked, 2 denotes a collimating optical system, 3 denotes a first prism,
Is a second prism, 5 and 6 are cylindrical lenses, 7
Denotes a converging optical system, 8 denotes a converging spot, 10-1 denotes a first ray group, 10-2 denotes a second ray group, and 11 denotes a complex parallel ray group.

FIG. 2 is a partially enlarged view of the semiconductor laser unit 1 and the collimating optical system 2 of FIG. 1, (a) is a plan view, and (b) is a side view. 1 are given the same numbers. .., 1-1, 1-2, 1-3,..., Individual array semiconductor lasers constituting the semiconductor laser unit 1;
Reference numerals 1 and 2-2 denote arrays of cylindrical optical elements constituting the collimating optical system 2, 9, 9-1, 9-2, 9-
3, ... are active layer stripes.

Hereinafter, a basic configuration of the present embodiment will be described. As shown in FIG. 2B, the semiconductor laser unit 1 includes individual array semiconductor lasers 1-1, 1-2, 1--1.
.., And each of the arrayed semiconductor lasers 1-1, 1-2, 1--1 as shown in FIG.
3,... Indicate a plurality of active layer stripes 9-1, 9-2, 9
-3,..., And the active layer stripe 9 is shown in FIG.
As shown in FIG. 2A, the width is as large as, for example, about 100 μm, and as shown in FIG. 2B, the thickness is as narrow as, for example, about 1 μm.

The collimating optical system 2 forms a parallel light beam group 10 by the collimating optical system 2 corresponding to each active layer stripe 9 and composed of an array 2-1 and 2-2 of a cylindrical optical element using, for example, a cylindrical lens. The parallel ray group 10 is divided into about two parts, and becomes a first ray group 10-1 and a second ray group 10-2 in FIG.
In the case of -1, the first prism 3 tilts the light beam direction, and the second prism 4 restores the light beam direction. As a result, FIG.
As shown in (b), the first ray group 10-1 and the second ray group 10-2 are superimposed in two steps in the direction orthogonal to the active layer stripe 9 to form a composite parallel ray group, and the cylindrical optical element 5
to go into.

The cylindrical optical elements 5 and 6 constitute a shaping optical system, and the width and height of the composite parallel light ray group are made to coincide with each other.

As described above, the parallel light group obtained by collimating the laser beam of the semiconductor laser unit by the collimating optical system is divided into the first light beam group and the second light beam group, and these are divided in the direction orthogonal to the active layer stripe. By stacking the light sources in two stages, the size of the light source in the active layer stripe direction can be reduced to １ ／, and the light collecting property can be improved. This is because when the light from a small light source is collimated into a parallel light,
This is because the parallelism of the light beams is good, and when the light is condensed by the light condensing optical system, the light is condensed into a small spot and the light condensing property is good.

In this embodiment, the size of the light source in the divided direction is halved by dividing the parallel light beam into two in the direction of the active layer stripe, and the light is superimposed in two steps in the direction orthogonal to the active layer stripe. , The size of the light source in the orthogonal direction is doubled. However, as described in the related art, the light source width in the active layer stripe direction is originally about 100 μm, which is 100 times as large as the thickness of the light source in the orthogonal direction of about 1 μm. Is also big,
The size ratio of the light source of width and thickness is about 100. Thus, as in the present embodiment, the size of the light source in the active layer stripe direction is reduced by half and the size of the light source in the orthogonal direction is doubled, thereby relatively improving the size ratio of the light source to 1/4. ,
Since the shape ratio of the width and thickness of the condensed spot corresponding to the size ratio of the light source is also １ ／, the condensing property can be greatly improved.

Incidentally, a cylindrical optical element (for example, a cylindrical lens) that makes the width of the composite parallel light beam group in the active layer stripe direction and the height in the orthogonal direction approximately coincide with each other.
By adding the shaping optical system consisting of, the beam shape of the complex parallel light ray group approaches a square, so that the aperture of the light collecting optical system can be used effectively, and the light collecting property can be further improved.

(Embodiment 2) FIG. 3 is a schematic diagram showing a configuration of a condensing laser device according to the present embodiment.
Is a plan view, and (b) is a side view. In FIG. 3, FIG.
The same parts are given the same numbers. Reference numeral 12 denotes a third prism, and reference numeral 13 denotes a fourth prism.

Hereinafter, the basic configuration of the present embodiment will be described. The semiconductor laser unit 1 is configured by superposing individual array semiconductor lasers 1-1, 1-2, 1-3,... As shown in FIG. As shown in FIG. 2A, each of the array semiconductor lasers 1-1, 1-2, 1-3,... Comprises a plurality of active layer stripes 9-1, 9-2, 9-3,. The layer stripe 9 has a wide width of, for example, about 100 μm as shown in FIG. 2A in a plan view, and a narrow thickness of, for example, about 1 μm as shown in FIG. 2B.

The collimating optical system 2 forms a parallel light beam group 10 by the collimating optical system 2 corresponding to each active layer stripe 9 and composed of, for example, a cylindrical optical element array 2-1 and 2-2 by a cylindrical lens. The parallel ray group 10 is divided into about two parts, and becomes a first ray group 10-1 and a second ray group 10-2 in FIG.
In the case of -1, the first prism 3 tilts the light beam direction, and the second light beam direction is restored by the second prism 4 so as to translate the first light beam group 10-1 in parallel with the active layer stripe.

The remaining second light beam group 10-2 is tilted by the third prism 12 and then returned to the original light beam direction by the fourth prism 13 so as to be orthogonal to the active layer stripe 9 in the second light beam group. 10-2 is translated. As a result, FIG.
As shown in (a) and (b), the first ray group 10-1 and the second ray group 10-2 are orthogonal to the active layer stripe 9 in two directions.
The beams are superimposed on each other and form a group of parallel rays of light, and enter the cylindrical optical element 5.

The cylindrical optical elements 5 and 6 constitute a shaping optical system, and the width and height of the composite parallel light ray group are made to coincide with each other.

As described above, the parallel light beam obtained by collimating the laser beam of the semiconductor laser unit by the collimating optical system is divided into the first light beam group and the second light beam group, and these are divided in the direction orthogonal to the active layer stripe. By stacking the light sources in two stages, the size of the light source in the active layer stripe direction can be reduced to １ ／, and the light collecting property can be improved. This is because when the light from a small light source is collimated into a parallel light,
This is because the parallelism of the light beams is good, and when the light is condensed by the light condensing optical system, the light is condensed into a small spot and the light condensing property is good.

In this embodiment, the size of the light source in the divided direction is halved by dividing the parallel light beam group into two in the direction of the active layer stripe, and the light is superposed in two steps in the direction orthogonal to the active layer stripe. , The size of the light source in the orthogonal direction is doubled. However, as described in the related art, the light source width in the active layer stripe direction is originally about 100 μm, which is 100 times as large as the thickness of the light source in the orthogonal direction of about 1 μm. Is also big,
The size ratio of the light source of width and thickness is about 100. Thus, as in the present embodiment, the size of the light source in the active layer stripe direction is reduced by half and the size of the light source in the orthogonal direction is doubled, thereby relatively improving the size ratio of the light source to 1/4. ,
Since the shape ratio of the width and thickness of the condensed spot corresponding to the size ratio of the light source is also １ ／, the condensing property can be greatly improved.

Note that a cylindrical optical element (for example, a cylindrical lens) that makes the width of the composite parallel light beam group in the active layer stripe direction substantially equal to the height in the orthogonal direction.
By adding the shaping optical system consisting of, the beam shape of the complex parallel light ray group approaches a square, so that the aperture of the light collecting optical system can be used effectively, and the light collecting property can be further improved.

In the structure of the first embodiment, two prisms are used, and in the structure of the second embodiment, four prisms are used. There is a feature that the number of necessary optical components is smaller than that of the configuration of the embodiment 2).

The prism used in the configuration of the first embodiment has a complicated shape in which one surface is doubly inclined, but the prism used in the configuration of the second embodiment is one. It has a simple form in which one surface is inclined only in one direction,
The configuration of (Embodiment 2) has a feature that the form of the prism can be simpler than the configuration of (Embodiment 1).

The configurations of (Embodiment 1) and (Embodiment 2) correspond to the array 2-1 of the cylindrical optical element.
And 2-2, the collimating optical system 2 uses a cylindrical optical element if the collimating optical system 2 is capable of collimating the laser beam from each active layer stripe into a parallel beam group. You don't have to.

Further, the configurations of (Embodiment 1) and (Embodiment 2) both have a shaping optical system including cylindrical optical elements 5 and 6 so that the width and height of the composite light beam group are matched. It is stated that the converging property can be further improved by making the beam shape of the composite parallel light beam 11 entering the condensing optical system 7 closer to a square, but it is not always necessary if the beam shape of the composite light beam group is originally closer to a square. Absent.

[0038]

As described above, according to the present invention, when the semiconductor laser unit is collimated and condensed by the condensing optical system, the ratio of the width to the thickness of the condensed spot is greatly improved and the condensing property is improved. For example, it is possible to improve the processing quality in laser processing and realize uniform excitation in solid-state laser excitation. The effect is very large.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a configuration of a focusing laser device according to an embodiment of the present invention.

FIG. 2 is an enlarged conceptual diagram showing a configuration of a part of a condensing laser device according to an embodiment of the present invention.

FIG. 3 is a conceptual diagram showing a configuration of a focusing laser device according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor laser unit 2 Collimating optical system 3 First prism 4 Second prism 5 Cylindrical lens 6 Cylindrical lens 7 Condensing optical system 8 Condensing spot 9 Active layer stripe 10 Parallel ray group 11 Complex parallel ray group 12 Third Prism 13 Fourth prism

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hiroki Ichihashi 3-10-1 Higashi-Mita, Tama-ku, Kawasaki-shi, Kanagawa F-term in Matsushita Giken Co., Ltd. 4E068 CD05 CD09 CD12 5F073 AB05 AB25 AB27 BA09 EA29

Claims (5)

[Claims] 1. A semiconductor laser unit in which an array semiconductor laser comprising a plurality of active layer stripes is stacked in a plurality of stages, and a collimating optical system for collimating each laser beam from each of the active layer stripes of the unit into a parallel light beam group. A converging laser device having a converging optical system for converging the parallel light beam group, wherein a first prism which inclines the light beam direction with respect to about half of the first light beam group of the parallel light beam group and the light beam direction again The first light group is moved in parallel by the second prism returning to the above, and the first light group is overlapped with the active layer stripe in two steps in a direction orthogonal to the remaining second light group of the parallel light group. A converging laser device, wherein the converging laser beam is a composite parallel light beam group. 2. A semiconductor laser unit in which an array semiconductor laser comprising a plurality of active layer stripes is stacked in a plurality of stages, and a collimating optical system for collimating each laser beam from each of the active layer stripes of the unit into a parallel light beam group. A converging laser device having a converging optical system for converging the parallel light beam group, wherein a first prism which inclines the light beam direction with respect to about half of the first light beam group of the parallel light beam group and the light beam direction again The first prism group is moved in parallel with the active layer stripe by the second prism returning to the third prism, and the third prism tilts the beam direction with respect to the remaining second beam group of the parallel beam group. The first light group and the second light group are moved in parallel with the active layer stripe by the fourth prism that restores the light direction. Is a composite parallel light beam, which is superimposed in two stages in a direction orthogonal to the active layer stripe. 3. A shaping optic comprising a cylindrical optical element, wherein a width of a complex parallel light beam in a direction of the active layer stripe and a height in a direction orthogonal to the active layer stripe are substantially equal to each other. A condensing laser device comprising a system. 4. The condensing laser device according to claim 3, wherein the cylindrical optical element is a cylindrical lens. 5. The condensing laser device according to claim 1, wherein the collimating optical system comprises an array of cylindrical lenses.