JPH11274618A - Optical system for laser beam illumination and laser device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To illuminate an object to be illuminated with a linear laser beam of a large output and uniform intensity distribution. SOLUTION: A laser beam emitted from a copper vapor laser 1 is transmitted through a bundle of optical fibers 3a, 3b and 3c and then directed into a condensing optical system 5, so that, in the optical system 5, images at light exit ends 4a, 4b and 4c of the fibers 3a, 3b and 3c are imaged on a dye solution flowing through a dye cell 6 in a Y axis direction by imaging optical systems f1 and f2 , and the images at the light exit ends 4a, 4b and 4c of the fibers 3a, 3b and 3c are also Koehler-illuminated linearly and uniformly on the dye cell 6 by a Koehler illumination optical system f3 in an X axis direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser beam irradiation optical system applied to, for example, a laser processing apparatus or a dye laser apparatus, and a laser apparatus using the same.

[0002]

2. Description of the Related Art As a laser excitation source such as laser processing or a dye laser, a laser beam having a point-like irradiation surface is converted into a linear shape with respect to an object to be irradiated, for example, a workpiece or a dye flow cell of a dye laser. Irradiation may be necessary.

In such a case, a laser beam is emitted from an optical waveguide such as a single optical fiber or a homogenizer, and the laser beam is irradiated on an object to be irradiated by a lens.

[0004] Here, as a lens, it is impossible to convert a point-shaped irradiation surface into a linear irradiation surface with a spherical lens. Therefore, an anamorphic lens is used to diverge or condense in only one direction. By doing so, the point-like beam profile is converted into a linear shape and irradiates the irradiation target.

[0005]

However, when it is desired to convert a laser beam into a long linear beam and irradiate the laser beam in order to increase the area for laser processing or excitation of the dye flow cell,
Since the irradiation surface of the laser beam is widened, the energy density of the laser is reduced.

For this reason, it is necessary to increase the energy of the incident laser beam in order to secure the laser energy required for laser processing or excitation. However, the energy of the incident laser beam is limited to the allowable value of the transmission energy of an optical waveguide such as an optical fiber. If the laser beam has a point-like irradiation surface, the laser beam having a point-like irradiation surface is treated as a laser beam having a linear irradiation surface while maintaining the laser energy density required for laser processing or excitation. The irradiation body cannot be irradiated.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a laser beam irradiation optical system and a laser device capable of irradiating a laser beam having a large output and a linear irradiation surface to an object to be irradiated with a uniform intensity distribution. .

[0008]

According to a first aspect of the present invention, there is provided a laser beam irradiation optical system for converting a laser beam having a plurality of point-like irradiation surfaces into a linear beam and irradiating the object with the laser beam. A plurality of laser emission end faces arranged one-dimensionally to emit laser beams, and a plurality of laser beams emitted from these laser emission end faces are irradiated onto an irradiation target in a direction perpendicular to the arrangement direction of the laser emission end faces. Is a laser beam irradiating optical system comprising: a condensing optical system that forms an image and uniformly irradiates linearly in the arrangement direction of the laser emission end face.

According to a second aspect of the present invention, in the laser beam irradiation optical system according to the first aspect, the condensing optical system includes an imaging optical system that forms an image in an arrangement direction of each laser emission end face;
And a Koehler illumination optical system acting on the arrangement direction of the laser emission end face.

According to a third aspect of the present invention, in the laser beam irradiation optical system according to the first aspect, a plurality of laser emission end faces are arranged at a focal position on the incident side of the condensing optical system, and the exit side of the condensing optical system is arranged. The object to be irradiated is arranged at the focal position of.

According to a fourth aspect of the present invention, there is provided a laser device for converting a laser beam having a plurality of point-shaped irradiation surfaces into a linear laser beam and irradiating the object with a laser beam. A light source, a plurality of optical waveguides each transmitting the laser beam output from the laser light source as a plurality of point-like laser beams, and one-dimensionally arranging each laser emission end face, and each laser emission of these optical waveguides A plurality of laser beams emitted from the end face are imaged on the irradiation object in a direction perpendicular to the arrangement direction of the laser emission end faces, and lines are formed on the irradiation object in the arrangement direction of the laser emission end faces. And a condensing optical system that irradiates the light uniformly.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a laser device applied to the excitation of a dye flow cell of a dye laser. FIG. 1 (a) is a configuration diagram viewed from the Y-axis direction, and FIG.
It is the block diagram seen from the axial direction.

A copper vapor laser (CVL) 1 is provided as a laser light source, that is, a dye laser excitation light source. Optical fiber bundles 3a, 3b and 3c are arranged on the optical path of the laser beam output from the copper vapor laser 1 via optical fiber incident optical systems 2a, 2b and 2c.

The optical fiber incident optical systems 2a, 2a
Reference numerals b and 2c denote laser beams output from the copper vapor laser 1 to be incident on the optical fiber bundles 3a, 3b and 3c. For example, an objective lens for a microscope is used.

Also, the optical fiber bundles 3a, 3b, 3c
As shown in FIG. 2, three optical fibers having a core diameter of 1.0 mm are arranged one-dimensionally in the X-axis direction. The figure shows the respective laser emitting end faces 4a, 4b, 4c of the optical fiber bundles 3a, 3b, 3c.

The condensing optical system 5 includes fiber bundles 3a, 3b
b, 3c, a plurality of point-like laser beams emitted from the respective laser emission end faces 4a, 4b, 4c are vertically (Y) aligned with the arrangement direction of the laser emission end faces 4a, 4b, 4c.
(In the axial direction), an image is formed on the dye flow cell 6, and Koehler irradiation is performed linearly and uniformly on the dye flow cell 6 in the arrangement direction (X-axis direction) of the laser emission end faces 4 a, 4 b, 4 c. Has become.

More specifically, the condensing optical system 5 includes the fiber bundle 3
imaging optical systems (imaging lenses) f ₁ , f ₂ acting in a direction perpendicular to the arrangement direction of the laser emission end faces 4 a, 4 b, 4 c of a, 3 b, 3 c (Y-axis direction); It has become these laser emitting end face 4a, 4b, the array direction of 4c (X axis direction) Koehler illumination optical system acting on (illumination lens) anamorphic optical system formed from f ₃ Metropolitan and.

With respect to such a condensing optical system 5, each of the laser emission end faces 4a, 4b,
Each of the arrangement of the dye flow cell 4c and the dye flow cell 6 is such that each of the laser emission end faces 4a, 4b, 4
c, and a focus position i on the exit side of the light-collecting optical system 5
Is provided with a dye flow cell 6.

The dye flow cell 6 circulates a dye solution which is an excitation medium for the dye laser. In the dye laser device, the dye solution is excited to emit a dye laser beam. .

Next, the operation of the laser device configured as described above will be described. The laser beam output from the copper vapor laser 1 is applied to optical fiber input optical systems 2a, 2b, 2
c, and enters the optical fiber bundles 3a, 3b, 3c via
The light is transmitted through these optical fiber bundles 3a, 3b, and 3c and is incident on the condensing optical system 5.

The condensing optical system 5 includes a fiber bundle 3a,
Each point-like laser beam emitted from each of the laser emission end faces 4a, 4b, and 4c of 3b and 3c is converted into a linear laser beam, and an image is formed on the dye flow cell 6.

That is, the image forming optical systems f ₁ and f ₂ correspond to FIG.
As shown in FIG.
The images of the laser emission end faces 4a, 4b, and 4c of b and 3c are formed on the dye solution flowing through the dye flow cell 6, that is, formed at positions called critical illumination.

As described above, in the Y-axis direction, the fiber bundle 3
Since the images of the laser emission end surfaces 4a, 4b, and 4c of the fiber bundles 3a, 3b, and 3c are formed on the dye flow cell 6, the laser emission end surfaces 4a, 4b, and 4c of the fiber bundles 3a, 3b, and 3c are formed.
Is reproduced on the dye flow cell 6 in the Y-axis direction.

Thus, the fiber bundle 3 shown in FIG.
a, 3b, and 3c, a uniform profile in the Y-axis direction, such as a point-like laser beam emitted from each of the laser emission end faces 4a, 4b, and 4c, has a clear contour as shown in FIG. 6 also has a clear excitation profile with a contour in the Y-axis direction.

On the other hand, as shown in FIG. 6, the Koehler illumination optical system f ₃ has fiber bundles 3a, 3b,
The image of each of the laser emission end surfaces 4a, 4b, and 4c of 3c is Koehler-irradiated linearly and uniformly to the dye flow cell 6 (that is, an image is formed at a position sufficiently distant from the position of critical illumination).

More specifically, as shown in FIG. 6, laser beams a ₁ and a ₁ emitted from the laser emission end faces 4a, 4b and 4c of the fiber bundle 3a located at the center of the lens.
a ₂ and a ₃ pass through the Koehler illumination optical system f ₃ and irradiate the focal point i on the emission side, that is, onto the dye solution of the dye flow cell 6 through the trajectories a ₁ ′, a ₂ ′ and a ₃ ′. Is done.

At this time, since the laser emission end faces 4a, 4b, 4c of the fiber bundle 3a are arranged at the center of the Koehler illumination optical system f ₃ and at the focal position o of this optical system f ₃ ,
The laser beams a ₁ , a ₂ , and a ₃ emitted from the laser emission end surfaces 4a, 4b, and 4c are irradiated as parallel rays onto the dye solution in the dye flow cell 6.

Laser beams b ₁ , b ₂ , b ₃ and c ₁ , c ₃ emitted from fiber bundles 3 b and 3 c arranged at an arbitrary distance from the center of Koehler illumination optical system f _3.
2, the laser beam b ₃ and c ₁ passing through the center of the Koehler illumination optical system f ₃ of the c ₃ after passing through the imaging optical system f ₂ also laser emitting end face 4a, 4b, as it angles emitted from 4c Dye flow cell 6 through trajectories b ₃ ′ and c ₁ ′
Is irradiated on the dye solution.

Further, the laser beams b ₁ , b ₂ , b ₃ and c ₁ , c ₂ , c ₃ emitted from the fiber bundles 3b and 3c, respectively.
Of the laser beams b ₂ and c ₂ emitted from the laser emission end faces 4a, 4b, and 4c at an angle of 0 degree,
₂ , the focal position i of the Koehler illumination optical system f ₃ through c ₂
Is irradiated onto the dye solution in the dye flow cell 6.

At this time, since the laser beams b ₂ and c ₂ enter the imaging optical system f ₁ at an angle parallel thereto, they are transmitted to the focal position i of the Koehler illumination optical system f ₃ . The laser beam b emitted from the fiber bundles 3b and 3c
_1, b _2, b ₃ and c _1, of c _2, c _3, the lens f ₃
Outgoing laser beams b ₁ and c _{3 at the} maximum angle with respect to
A laser emitting end surface 4a by passing through the Koehler illumination optical system f _3, 4b, trajectory b ₁ is the exit angle exactly opposite angle from 4c ', c _3' dye in the dye flow cell 6 through the Irradiate on the solution.

As described above, in the Koehler illumination optical system f ₃ , the laser output end faces 4 a, 4 b, 4 c of the fiber bundles 3 a, 3 b, 3 c and the dye flow cell 6 are connected to the focal positions o, i of the Koehler illumination optical system f _3. , The laser beams emitted from the fiber bundles 3a, 3b, 3c are respectively set to xx on the dye flow cell 6.
Is converted to a linear shape and irradiated.

Accordingly, Koehler illumination is provided in the X-axis direction, so that the fiber bundle 3a in the X-axis direction shown in FIG.
The profile pattern of the three peaks having three peaks 3b and 3c is converted into a single peak excitation profile pattern on the dye flow cell 6 in which the bottom of the contour portion is drawn in the X-axis direction shown in FIG.

That is, when viewed three-dimensionally, the fiber bundle 3
Although the laser emission end faces 4a, 4b, and 4c of a, 3b, and 3c have an aggregated pattern of light spots as shown in FIG. 7, a uniform excitation pattern is formed on the dye flow cell 6 as shown in FIG. Is converted.

As described above, in the dye laser apparatus, when the dye solution flowing in the dye flow cell 6 is irradiated with the excitation light and excited, the dye laser beam oscillates. As described above, in the above-described embodiment, the laser beam output from the copper vapor laser 1 is applied to the optical fiber bundles 3a, 3b, 3c.
And is incident on the condensing optical system 5. In the condensing optical system 5, the laser emission end faces 4 of the fiber bundles 3 a, 3 b, and 3 c in the Y-axis direction by the imaging optical systems f ₁ and f _2.
a, 4b, the image of 4c imaged on a dye solution flowing through the dye flow cell 6, and the fiber bundle 3a in the X-axis direction by the Kohler illumination optical system f _3, 3b, each laser emitting end surface 4a of the 3c, 4b, 4c Is uniformly irradiated on the dye flow cell 6 with a linear irradiation surface, so that the laser energy density required for exciting the dye solution by the dye laser is maintained, that is, a large output and a dot-shaped irradiation surface are provided. Dye flow cell 6 using laser beam as excitation profile laser beam having linear irradiation surface with uniform intensity distribution
Can be irradiated on top.

Thus, a plurality of point-like laser beams are converted into a linear laser beam having a uniform intensity distribution and irradiated to the dye flow cell 6, whereby the dye laser can be oscillated. The present invention is not limited to the above-described embodiment, but may be modified as follows.

For example, the fiber bundles 3a, 3b, 3c
The number of laser beams is not limited to three, and a plurality of point-like laser beams may be transmitted and a long linear laser beam may be obtained by the focusing optical system 5.

In the above-described embodiment, the case where the present invention is applied to the excitation of the dye solution flowing through the dye flow cell 6 of the dye laser has been described.
The present invention may be applied to a laser processing apparatus using a laser device and using a workpiece such as a metal as an irradiation object.

[0038]

As described above in detail, according to the present invention, it is possible to provide a laser beam irradiation optical system and a laser device capable of irradiating an object to be irradiated with a high-power linear laser beam with a uniform intensity distribution. .

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment in which a laser device according to the present invention is applied to excitation of a dye flow cell.

FIG. 2 is a diagram showing each laser emission end face of the optical fiber bundle.

FIG. 3 is a diagram illustrating an operation of an image forming optical system in a condensing optical system.

FIG. 4 is a diagram showing a profile of a point-like laser beam emitted from a laser emission end face.

FIG. 5 is a diagram showing a uniform excitation profile in the X-axis direction on a dye flow cell.

FIG. 6 is a diagram showing an operation of a Koehler illumination optical system in a light collecting optical system.

FIG. 7 is a diagram three-dimensionally showing an aggregation pattern of light spots on each laser emission end face of the fiber bundle.

FIG. 8 is a diagram three-dimensionally showing a uniform excitation pattern on a dye flow cell.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Copper vapor laser (CVL), 2a, 2b, 2c ... Optical fiber incidence optical system, 3a, 3b, 3c ... Optical fiber bundle, 4a, 4b, 4c ... Laser emission end face, 5 ... Condensing optical system, 6 ... Dye flow cell , F ₁ , f ₂ : imaging optical system, f ₃ : Koehler illumination optical system.

Claims (4)

[Claims] 1. A laser beam irradiation optical system that converts a laser beam having a plurality of point-shaped irradiation surfaces into a linear shape and irradiates an object to be irradiated, and one-dimensionally emits the plurality of laser beams. A plurality of laser emission end faces arranged, and the plurality of laser beams emitted from these laser emission end faces are imaged on the irradiation object in a direction perpendicular to the arrangement direction of the laser emission end faces, and the laser A condensing optical system for uniformly irradiating linearly with respect to the direction of arrangement of the emission end faces. 2. The condensing optical system includes: an imaging optical system that forms an image in an arrangement direction of each of the laser emission end faces; and a Koehler illumination optical system that acts in an arrangement direction of the laser emission end faces. 2. The laser beam irradiation optical system according to claim 1, wherein the optical system is formed from: 3. The light-emitting device according to claim 1, wherein the plurality of laser emission end faces are arranged at a focus position on an incident side of the condensing optical system, and the irradiation target is arranged at a focus position on an emission side of the condensing optical system. The laser beam irradiation optical system according to claim 1, wherein 4. A laser device for converting a laser beam having a plurality of point-shaped irradiation surfaces into a linear laser beam and irradiating the object with a laser beam, comprising: a laser light source for outputting the point-like laser beam; A plurality of optical waveguides each transmitting the laser beam output from the laser light source as a plurality of point-like laser beams, and arranging each laser emission end face in one dimension; and emitting the laser light from each laser emission end face of these optical waveguides. The plurality of laser beams thus formed are imaged on the irradiation object in a direction perpendicular to the arrangement direction of the laser emission end faces, and the irradiation object is arranged in the arrangement direction of the laser emission end faces. And a condensing optical system for uniformly irradiating the laser beam linearly.