JPH05291659A - Correcting mechanism for laser beam - Google Patents

Abstract

PURPOSE:To make it possible to transmit laser beam in the far distance by keeping a specific shape and size of the laser beam with no reduction of output power of the laser beam. CONSTITUTION:A mechanism for correction laser beam is provided with a beam projected image correcting means 22 consisting of a concave lens 23 arranged on the output side of a laser device 21, and a movable convex lens 24. The beam projected image correction means 22 is provided with an inclination driving means which can incline the convex lens 24 in a desired direction against an orbit of laser beam 10 to be applied from the laser device 21, and is provided with a horizontal driving means which can move along the orbit. In addition, the beam projected image correction means 22 is provided with beam image sensing means 51a, 51b which output beam projected image at two positions on the orbit, and an image processing means 55 which outputs a beam correction signal by processing the image signal, and a lens control means 56 which operates the inclination driving means and horizontal driving means in response with the beam correction signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser device such as a solid-state laser device, a gas laser device, a semiconductor laser device, a dye laser device, etc. A transmission laser beam correction mechanism.

[0002]

2. Description of the Related Art Laser devices are now widely used in various fields such as communication, processing, radar, and distance measurement.

Further, there are various types of laser devices such as solid-state lasers, gas lasers, semiconductor lasers, dye lasers, etc., depending on the laser material that amplifies laser light.

FIG. 5 is a block diagram showing a conventional dye laser device 1.

The dye laser device 1 is provided with a dye cell 5 containing a dye, which is a laser substance, between a resonator 4 composed of an output mirror 2 and a grating 3, and the dye cell 5 is provided with an excitation laser beam. The laser beam 6 is extracted from the output mirror 2 by irradiating with.

Further, the dye laser device 1 is provided with an etalon 7 and a prism 8 in order to extract a laser beam having a specific wavelength.

Further, in the dye laser device 1, the cross-sectional size of the laser beam 6 is adjusted to a desired size by the beam telescope 9 and the laser beam 10 is output to the outside.

With such a dye laser device 1, it is possible to irradiate a laser beam 10 on a target 11 placed at a distance.

[0009]

On the other hand, for example, when the laser beam 10 is used to separate isotope atoms,
Predetermined energy is input by overlapping a plurality of beams on a predetermined region.

For this reason, the laser beam 10 must be transmitted and irradiated to the distant target 11 while maintaining its cross-sectional shape and size at a predetermined shape and size.

However, when the optical elements such as the output mirror 2, the grating 3, the dye cell 5, the prism 8 and the beam telescope 9 described above are decentered from a predetermined optical axis, the laser beam 10 is transmitted far. As a result, the cross-sectional shape or size thereof changes from, for example, a circular cross-section 12 to an elliptical cross-section 13 as shown in FIG. 5, resulting in a problem that a predetermined energy density cannot be obtained on the target.

Such a change in the cross-sectional shape or size of the laser beam may occur not only in the eccentricity of the optical element but also in the density fluctuation of the laser substance, the thermal deformation of the laser substance, etc. The above problems also occur in laser devices, semiconductor laser devices, and the like.

If the above-mentioned problem is to be avoided by adjusting the laser device, the output of the laser device may be reduced.

The present invention has been made in consideration of the above-mentioned circumstances, and a laser capable of maintaining a predetermined shape and size of a laser beam and transmitting it to a distant place without reducing the output of the laser beam. It is an object to provide a beam correction mechanism.

[0015]

In order to achieve the above object, the laser beam correction mechanism of the present invention has a lens or mirror arranged on the output side of a laser device as described in claim 1, and the lens or mirror is provided. At least one of them is movably provided with a beam projection image correction means.

[0016]

According to the laser beam correction mechanism of the present invention, the lens or the mirror is disposed on the output side of the laser device, and at least one of the lens and the mirror is configured to be movable. Alternatively, the size can be corrected, and the center position of the projected image of the laser beam can be corrected.

Therefore, it becomes possible to maintain the laser beam in a predetermined shape and size and transmit the laser beam to a distant place, and to correct the shape or size of the projected image of the laser beam to adjust the center position of the projected image. The shift can be corrected.

Further, since such correction can be performed independently of the laser device, there is no fear of reducing the output of the laser beam.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the laser beam correcting mechanism of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing the laser beam correction mechanism of this embodiment.

The laser beam correction mechanism of this embodiment comprises a laser device 21 for outputting a laser beam.

The laser device 21 is a solid-state laser device,
It is composed of a gas laser device, a semiconductor laser device, a dye laser device and the like.

The laser beam correction mechanism of this embodiment also includes a laser beam 1 output from the laser device 21.
A beam projection image correction means 22 capable of correcting the size or shape of the projection image of 0 is provided.

The beam projection image correction means 22 comprises a concave lens 2
3 and the convex lens 24 are arranged on the output side of the laser device 21, and the concave lens 23 and the convex lens 24 are attached to the concave lens holder 25 and the convex lens holder 26, respectively.

The convex lens holder 26 is constructed so that the convex lens 24 is movable.

The focal lengths of the convex lens 23 and the concave lens 24 are preferably set to be equal to or a fraction of the transmission distance of the laser beam. The larger the focal length is set, the more accurately the above-mentioned correction is performed. be able to.

FIG. 2 is a perspective view of the convex lens holder 26 to which the convex lens 24 is attached.

As can be seen in FIG. 2, the convex lens holder 2
Reference numeral 6 includes a tilt driving means 31 capable of tilting the convex lens 24 in a desired direction with respect to the trajectory of the laser beam 10, and a horizontal driving means 32 capable of moving along the trajectory.

The tilt drive means 31 includes a tilt plate 33 in which the convex lens 24 is fitted and a rotary plate 35 via a hinge portion 34.
On the other hand, the inclined plate 33 is connected to a shaft 38 of a rotary drive mechanism (not shown) such as a servomotor via a rod 36 and a coupling 37.

The rod 36 is preferably threaded at its tip, and the tip is engaged with the screw hole of the inclined plate 33.

The tilt drive means 31 further includes a rotary plate 35.
Is attached to the fixed plate 44 rotatably around the above-mentioned track, and the rotary plate 35 is connected to the rod 41 via, for example, a rack and pinion mechanism (not shown). It is connected via 42 to a shaft 43 of a rotary drive mechanism (not shown) such as a servomotor.

That is, the tilt drive means 31 can tilt the convex lens 24 by a desired turning angle α with respect to the trajectory of the laser beam 10 at a rotation position of a desired rotation angle θ.

On the other hand, the horizontal driving means 32 slidably mounts the moving plate 45 to which the above-mentioned fixed plate 44 is attached to the fixed plate 46, and the movable plate 45 is moved by, for example, a rack and pinion mechanism (not shown). It is connected to a rod 47, and the rod 47 is connected via a coupling 48 to a shaft 49 of a rotary drive mechanism (not shown) such as a servomotor.

That is, the horizontal driving means 32 can move the convex lens 24 along the trajectory of the laser beam 10 by a desired moving amount m.

Referring again to FIG. 1, the beam projection image correction means 22 includes two sets of beam imaging means 51a and 51b capable of outputting the beam projection images at the two positions A and B on the orbit as image signals. Equipped with.

The beam imaging means 51a and 51b have beam splitters 52a and 52b arranged at positions A and B, respectively.
The laser beams branched from the beam splitters 52a and 52b are projected on the beam projection plates 53a and 53b, and the projected images are output as image signals by the CCD cameras 54a and 54b.

The beam projection image correction means 22 also comprises an image processing means 55 for image-processing the above-mentioned image signal and outputting a beam correction signal.

The image processing means 55 evaluates the shape and size of each projected image at the positions A and B by image-processing the two image signals, and determines the shape difference and size between the positions A and B. The difference is output as a beam correction signal.

The beam projection image correction means 22 also includes a lens control means 56 for operating the tilt drive means 31 and the horizontal drive means 32 in response to the above-mentioned beam correction signal.

The lens control means 56 will be described with reference to FIG. 2 so as to minimize the difference in shape between the positions A and B by using the beam correction signal representing the difference in shape between the positions A and B. The rotation angle θ and the turning angle α of the convex lens 24 are calculated, and then the rotation drive mechanism described above is controlled so that the convex lens 24 is driven to the calculated value.

Further, the lens control means 56 controls the positions A and B.
By using the beam correction signal that represents the difference in size between the positions A and B, the difference in size between the positions A and B is reduced as much as possible.
The amount of movement m of the convex lens 24 described with reference to FIG. 2 is calculated, and then the above-mentioned rotary drive mechanism is controlled so that the convex lens 24 is driven to the calculated value.

Here, the above-mentioned correction is performed when the transmission distance is equal to
When the laser beam is longer than 00 m, the projection direction of the laser beam may fluctuate and the laser beam may not be irradiated to a predetermined position.

Therefore, the laser system of this embodiment also includes a beam projection direction correction means 61 capable of correcting the projection direction of the laser beam 10.

The beam projection direction correction means 61 has mirrors 62a and 62b arranged on the output side of the laser device 21, and the mirrors 62a and 62b are movable.

The beam projection direction correction means 61 responds to the beam correction signal output from the image processing means 55, and the mirror 6
A mirror control unit 63 for driving and controlling 2a and 62b is provided.

This beam correction signal is used as the image processing means 55.
It is a signal representing the difference between the center points of the respective projected images at the positions A and B evaluated by.

Next, using the laser system of the present embodiment, the shape of the projected image of the laser beam irradiated at a distance,
The procedure for correcting the size and projection position is shown in FIG.
This will be explained with reference to (d).

In FIG. 3, the laser beam 10 output from the laser device 21 of FIG.
4 shows how the target 11 is irradiated through the mirrors 62a and 62b, and the positions A and B show the positions of the beam splitters 52a and 52b in FIG.

Here, the position A is the mirrors 62a and 62b.
Position B is near the target 11.

Further, FIG. 3 shows the projected image of the laser beam at the position B projected on the xy plane in which the trajectories of the laser beam are orthogonal to each other, in the hatched area, and FIG. 3 shows a projected image of the laser beam before correction in FIG.

These projected images are beam imaging means 51.
a, 51b can be obtained.

As can be seen from FIG. 3A, the projected image at the position A is near the output side of the laser device 21,
The projected image at the position B is almost circular while it is not affected by the eccentricity of the optical element in the laser device 21 and the fluctuation of the density distribution of the laser substance.
Since it has been transmitted over a long distance, it is deformed into an elliptical shape due to the influence of the above-mentioned eccentricity and the like.

In order to match such an elliptical projection image with the projection image at the position A, the correction is performed in the following procedure.

First, the image signals of these projected images created by the beam imaging means 51a and 51b are sent to the image processing means 55.

Next, the image processing means 55 performs image recognition to evaluate the shape of each projected image.

Next, in order to minimize the difference between the shapes at the positions A and B, here the difference between the circle and the ellipse,
The rotation angle θ and the turning angle α of the convex lens 24 are obtained, and these values are sent to the lens control means 56.

Then, the lens control means 56 operates the tilt drive means 31 so that the rotation angle θ and the turning angle α of the convex lens 24 become the above-mentioned values.

Here, in general, when a convex lens is tilted around a predetermined axis, the focal length on a plane including this axis does not change as compared with that before tilting, but the focal length on a plane orthogonal to this plane is , Shorter than before tilting.

That is, the laser beam is focused on different positions in the vertical and horizontal directions.

Therefore, as shown in FIG. 4, when a laser beam having a circular cross section is passed through a convex lens and the convex lens is tilted around a predetermined axis, the projected image of the laser beam is transmitted as far away as described above. Is transformed into an ellipse whose major axis is an axis parallel to the predetermined axis.

If this principle is used in reverse, if a laser beam having different focal lengths in the vertical direction and the horizontal direction, that is, a laser beam having a projected image of an elliptical shape is passed through a convex lens inclined by a predetermined angle, it is corrected into a circle. be able to.

Therefore, in order to correct the ellipse shown in FIG.
It is only necessary to rotate 4 around the orbit of the laser beam by θ to make the turning axis of the convex lens 24 parallel to the minor axis of the ellipse, and to turn about the turning axis by the turning angle α.

FIG. 3B shows a projected image at B after the convex lens 24 is rotated and rotated by the above-described rotation angle θ and rotation angle α.

When the convex lens 24 is tilted, the projection direction of the laser beam shifts to the broken line direction, which can be corrected as described later.

Next, the moving amount m of the convex lens 24 is evaluated by the image processing means 55 so that the difference between the size of the circle of the projected image at the position B and the size of the circle of the projected image at the position A is reduced as much as possible. , The movement amount m is sent to the lens control means 56.

Then, the lens control means 56 drives and controls the horizontal drive means 32 so that the convex lens 24 moves by the movement amount m.

The projected image after the convex lens 24 has moved by the moving amount m is shown in FIG. 3 (c).

Next, the image processing means 55 uses the mirrors 62a, so that the difference between the center position of the circle of the projected image at the position B and the center position of the circle of the projected image at the position A is minimized.
The rotation angle of 62b is evaluated and this rotation angle is sent to the mirror control means 63.

Next, the mirror control means 63 drives and controls the mirrors 62a and 62b so that the mirrors 62a and 62b rotate by the above-described rotation angle.

FIG. 3 (d) shows a projected image after the mirrors 62a and 62b are rotated by the above-mentioned rotation angle.

In this way, the projected image at the position B can be matched with or as close as possible to the projected image at the position A.

In this embodiment, the beam projection image correcting means is provided on the output side of the laser device. However, as described in the prior art, if a beam telescope is provided in the laser device, this beam telescope will be used. The beam projection image correction means may be configured by using this.

In this embodiment, the lens drive means is used to operate the tilt drive means and the horizontal drive means. However, the present invention is not limited to this, and the operator outputs the output signal of the image processing means. It may be configured to be manually operated while checking.

In this embodiment, the convex lens holder is driven, but the concave lens holder may be driven.

In the present embodiment, the convex lens and the concave lens are combined one by one to form the beam projection image correcting means, but a plurality of lenses of other types may be combined.

[0076]

As described above, the laser beam correction mechanism of the present invention is a beam projection image in which a lens or a mirror is arranged on the output side of a laser device and at least one of the lens and the mirror is movable. Since the correction means is provided, the shape or size of the projected image of the laser beam can be corrected.

Therefore, the laser beam can be transmitted to the distance while maintaining the predetermined shape and size, and the center position of the projected image can be adjusted by correcting the shape or size of the projected image of the laser beam. The shift can be corrected.

Further, since such correction can be performed independently of the laser device, there is no fear of lowering the output of the laser beam.

[Brief description of drawings]

FIG. 1 is a block diagram of a laser beam correction mechanism of this embodiment.

FIG. 2 is a perspective view of a convex lens holder 26 of the laser beam correction mechanism of FIG.

FIG. 3 is an explanatory view explaining the operation of the laser beam correction mechanism of the present embodiment.

FIG. 4 is an explanatory diagram illustrating the principle used in this embodiment.

FIG. 5 is a block diagram of a conventional laser beam correction mechanism.

[Explanation of symbols]

 10 laser beam 21 laser device 22 beam projection image correcting means 23 concave lens 24 convex lens 25 concave lens holder 26 convex lens holder 31 tilt driving means 32 horizontal driving means 51a beam imaging means 51b beam imaging means 55 image processing means 56 lens control means 61 beam Projection direction correcting means 62a mirror 62b mirror

Claims (2)

[Claims] 1. A laser beam correction mechanism comprising a beam projection image correction means in which a lens or a mirror is arranged on the output side of a laser device and at least one of the lens and the mirror is movable. 2. The beam projection image correction means comprises the lens as a concave lens and a convex lens, and at least one of the concave lens and the convex lens is desired for a trajectory of a laser beam emitted from the laser device. 2. The laser beam correction mechanism according to claim 1, further comprising: tilt driving means capable of tilting in a direction, and horizontal driving means capable of moving at least one of the concave lens and the convex lens along the trajectory.