JP2002151778A - Laser oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify an optical system and facilitate adjustment operation by fixing the output mirror of a laser oscillator. SOLUTION: The laser oscillator comprises a solid laser medium, an excitation light source for exciting the solid laser medium, an output mirror that is located on the light axis of a laser beam being emitted from the solid laser medium and is provided opposite to one end face of the solid laser medium, and a total reflection mirror for composing the output mirror and the resonator while being provided opposite to the other end face. The laser oscillator fixes the output mirror and at the same time provides the total reflection mirror with an adjustment mechanism for finely adjusting the light axis of the laser beam output.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a laser oscillator that facilitates maintenance.

[0002]

2. Description of the Related Art Laser oscillators are used for processing such as laser marking, trimming, cutting, and welding.

FIG. 1 is a schematic diagram of a laser oscillator. The laser oscillator shown in this figure includes a solid-state laser medium 1 and
An excitation light source 2 disposed near the solid-state laser medium 1 to excite the same; a total reflection mirror 4 disposed on one side of the optical axis of a laser emitted from the solid-state laser medium 1; And an output mirror 5 disposed on the other side. The total reflection mirror 4 and the output mirror 5 are disposed so as to face each other via the solid-state laser medium 1 so as to be able to repeatedly reflect light therebetween, and constitute a resonator for amplifying light.
The output mirror 5 partially transmits the amplified laser light and outputs it. On the laser beam output side of the output mirror 5, a scanner unit for controlling a processing position can be provided (not shown). Inside the scanner section, while directing the laser beam from the output mirror 5 in a predetermined direction,
Two movable mirrors for scanning in the Y direction are built in (not shown here). An Fθ lens 6 is attached to the emission portion of the scanner unit, and an object is placed on the work surface 3 at the focal position of this lens.

The output mirror 5 and the total reflection mirror 4 shown in FIG. 1 are positioned and fine-tuned so that the laser is resonated most efficiently and a laser with high processing accuracy is oscillated via the Fθ lens 6. .

In general, factors that improve the processing accuracy required for the laser output of a laser oscillator used for a laser marker or the like include beam quality and laser output power. Among them, the laser output power depends on how efficiently the power of the excitation light source can be converted by the solid-state laser medium 1.

[0006] The good beam quality means that the intensity distribution of the laser beam is close to a Gaussian distribution. Generally, the quality of the laser beam is not uniform in all areas. FIG. 2 shows how the intensity distribution varies depending on the quality of the laser beam. As shown in FIG. 2A, the intensity distribution of a high-quality laser beam has a Gaussian distribution type waveform, whereas the intensity distribution of a poor-quality laser beam shown in FIG. The distribution looks like a spread.

Normally, the laser beam reciprocates between the output mirror 5 and the total reflection mirror 4 inside the resonator, and is amplified each time it passes through the solid-state laser medium 1, and is amplified from the solid-state laser medium 1 to the output mirror 5
Some of the light traveling to the output mirror 5 as shown in FIG.
Is output as a laser beam.
For this reason, if the quality of the beam emitted from one end face of the solid-state laser medium toward the output mirror 5 is poor, the quality performance of the laser emitted to the outside deteriorates. Therefore, FIG.
As shown in (1), the solid-state laser medium 1 is generally arranged close to the output mirror 5 so that only high-quality beams can reciprocate in the resonator. With this arrangement, a high-quality beam is amplified, and a high-performance laser is emitted to the outside.

On the other hand, the spot diameter at the focus position on the work surface depends on the beam diameter and beam quality incident on the Fθ lens. The larger the diameter of the beam incident on the Fθ lens, the better the beam quality, in other words, the closer the intensity distribution of the laser beam is to the Gaussian distribution, the smaller the spot diameter at the focal position and the higher the power density.

When a laser oscillator is used, for example, as a laser printing machine, the focal position on the surface of the work is the printing position of the laser printing machine. Therefore, when the spot diameter is small, finer printing is possible. Conversely, if the spot diameter at the printing position is large, the power is not converged, so that fine printing cannot be performed or printing cannot be performed on a work requiring a high power density such as metal.

In order to increase the spot diameter of the beam incident on the Fθ lens, it is necessary to use a beam expander to increase the beam diameter to a desired one.

[0011]

However, in order to efficiently oscillate the laser and obtain a high-quality laser output as described above, the output mirror and the total reflection mirror are accurately fixed at predetermined positions, and the positional deviation is caused. And no inclination. If any of the mirrors is slightly tilted, the optical axis shifts and the output decreases.

For this reason, it is important to adjust the position of both the output mirror and the total reflection mirror in order to stably and efficiently emit the laser to the outside. This adjustment has been performed regularly not only at the time of assembling the laser oscillator but also in the process of using the device in order to avoid deterioration and deformation due to aging. However, adjusting both mirrors was a very complicated and difficult task. Not only is it difficult to make reliable adjustments with both mirrors, but also the adjustment man-hours increase, which takes time and effort.
Further, even if the adjustment is made once, there are many adjustment positions, and the adjustment may be confused by other adjustments.
Furthermore, the output mirror and the total reflection mirror require different degrees of adjustment due to the difference in their functions, and for example, the amount of movement is different from each other. For this reason, if the mirror requiring more strict adjustment fluctuates, the output of the laser and the optical axis of the emitted laser light will be greatly affected, and the stability of the entire apparatus may be lost.

Further, in the conventional laser oscillator, the number of adjustment points at the time of maintenance is large and complicated, and dust and dirt at the work site may adhere to the inside of the apparatus at the time of maintenance work and cause malfunction. The tuning portion of the laser oscillator spans the entire oscillator, including the output mirror, total reflection mirror, and aperture inside the resonator. For this reason, when adjusting, it was necessary to remove the device cover of the laser oscillator and perform the adjustment. However, depending on the situation in which the laser oscillator is used, it may be installed in a dusty or dusty place in a factory, and it is preferable to remove the cover in an oily, dusty, etc. environment that stains the optical member. Not that. If dust or the like adheres to the optical path, the efficiency is significantly reduced. Further, iron powder, dust, and the like may enter circuit components and cause malfunction.

The present invention has been developed to prevent such adverse effects. An important object of the present invention is to provide a laser oscillator capable of simplifying the adjustment work of a mirror and facilitating maintenance, and also capable of obtaining a stable laser output by blocking adverse effects such as dust during the adjustment work. Is to do.

[0015]

According to a first aspect of the present invention, there is provided a laser oscillator, a solid-state laser medium, an excitation light source for exciting the solid-state laser medium, and light emitted from the solid-state laser medium. A total reflection mirror positioned on the optical axis of the laser light; an output mirror facing the total reflection mirror via the solid laser medium; and a housing for housing the solid laser medium, the total reflection mirror, and an output mirror. ing. Further, the laser oscillator is characterized in that at least the output mirror is fixed to a base provided in the housing.

In the laser oscillator according to a second aspect of the present invention, an adjustment mechanism capable of adjusting the angle of the total reflection mirror so that the optical axis of the laser beam output can be finely adjusted is provided only on the total reflection mirror side. It is characterized by being provided.

Further, in the laser oscillator described in claim 3 of the present invention, the adjusting mechanism is housed in the housing, and the adjusting mechanism is operated on the housing so that the adjusting mechanism can be operated from outside the housing. It is characterized by providing a window.

Further, in the laser oscillator according to a fourth aspect of the present invention, the operation window is separated from the portion where the optical system member is disposed in the housing to have a dustproof property. A cylindrical guide extending from a window to the adjustment mechanism inside the housing is provided.

Further, in the laser oscillator according to the present invention, the output mirror is a double-sided concave lens, and the laser beam for expanding the laser output light output from the output mirror to an arbitrary beam diameter. It is characterized by constituting an expander.

Further, a laser oscillator according to a sixth aspect of the present invention is characterized in that a laser pointer is provided on a back surface of the total reflection mirror.

Further, a laser oscillator according to a seventh aspect of the present invention is characterized in that a cooling path is arranged near the base.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. However, the embodiments described below exemplify a laser oscillator for embodying the technical idea of the present invention, and the present invention does not limit the laser oscillator to the following.

Further, in this specification, in order to make it easy to understand the claims, the numbers corresponding to the members shown in the embodiments will be referred to as “claims” and “ In the column of “means”. However, the members described in the claims are not limited to the members of the embodiments.

Hereinafter, the laser oscillator and the like shown in the present invention are partially exaggerated for explanation.
It does not always correspond to what accurately represents the actual positional relationship, distance, size, and the like.

FIG. 1 schematically shows the configuration of a laser oscillator according to one embodiment of the present invention. In this figure, a laser marker is shown as an example. The laser marker shown in the figure is provided with a solid-state laser medium 1, a total reflection mirror 4 on one end face with its optical axis aligned with it, and an output mirror 5 on the other face for extracting a part of laser output. The laser marker excites the solid-state laser medium 1 by the excitation light source 2 and outputs laser light. The output laser light is reflected between the output mirror 5 and the total reflection mirror 4 and amplified in the resonator, and the amplified laser light passes through the output mirror 5 and is output to the outside.

As the excitation light source 2, an excitation lamp, a semiconductor laser or the like can be used. For the solid laser medium 1, a YAG crystal or the like can be used. Although the example of FIG. 1 describes the case where a YAG rod is used as the solid-state laser medium, the laser oscillator of the present invention is not limited to a YAG laser. In addition, an excitation lamp, a semiconductor laser, or the like can be used as the excitation light source 2. These excitation light sources 2 are provided with driving means for driving by adding an excitation lamp current, an excitation LD current, and the like according to the type of light source used.

Hereinafter, the shape of each mirror will be described from the viewpoint of beam quality and conversion efficiency. The wavefront of a laser beam having a Gaussian distribution has a property that the most narrowed portion is a flat surface and the spherical surface is always spread around the flattened portion. The same applies to a laser beam from a laser oscillator. Using a concave mirror with the same curvature as the spherical surface,
It is possible to stably and efficiently confine the laser beam inside the resonator.

FIG. 3 shows how the laser beam is emitted from the resonator via the output mirror 5. As shown in this figure, the beam diameter is maximum on the surface incident on the output mirror 5 which is a concave mirror.

Next, the optimum arrangement of the solid-state laser medium in consideration of the efficiency of the laser output will be examined with reference to FIGS. FIG. 4 shows an example in which the solid-state laser medium 1 is arranged closer to the output mirror 5, and FIG. 5 shows an example in which the solid-state laser medium 1 is arranged farther away.

In order to efficiently amplify the laser beam reciprocating between the solid-state laser medium 1 and the resonator, it is desirable that the solid-state laser medium 1 be irradiated with the laser beam over as wide a range as possible. Therefore, the more the laser beam coincides with the solid-state laser medium 1, the better the efficiency of laser output. For this reason, if the solid-state laser medium 1 is arranged at a position where the spread of the laser beam becomes large, the efficiency will be improved accordingly. Therefore, as shown in FIG. 4, the solid-state laser medium 1 is arranged close to the output mirror 5 so that the overlap with the solid-state laser medium 1 is increased at a position where the spread of the laser beam is large. This arrangement has higher excitation efficiency than the arrangement in which the solid-state laser medium 1 is separated from the output mirror 5 to reduce the irradiation volume of the laser beam as shown in FIG. 5, and can amplify a high-quality beam as described above. it can.

In order to increase the overlap between the solid-state laser medium and the laser beam, there is a method of changing the thickness of the solid-state laser medium in addition to the method of changing the position of the solid-state laser medium. Specifically, by reducing the cross-sectional area of the solid-state laser medium, the ratio of the laser beam overlapping the solid-state laser medium can be increased. However,
As the solid-state laser medium is elongated, there is a problem that the excitation efficiency is significantly reduced even when the optical axis of the laser beam in the resonator and the central axis of the solid-state laser medium are slightly shifted. As described above, in the method of changing the thickness of the solid-state laser medium, strictness of the angle and positioning is required, and there is a problem that a slight deviation deteriorates the laser conversion efficiency. Therefore, in this embodiment, a method of changing the position rather than changing the thickness of the solid-state laser medium is employed.

Next, the intensity distribution of the laser beam will be described with reference to FIG. A beam of good quality, that is, a beam whose intensity distribution is close to a Gaussian distribution, has a smaller spread and a smaller beam diameter than a beam of poor quality when the wavefront has the same curvature. Therefore, the distribution of the high-quality laser beam is converged as shown in FIG. 6A, and the distribution of the poor-quality beam is expanded as shown in FIG. 6B.

FIG. 7 shows the arrangement of the solid-state laser medium 1 in each of the above. Since the solid-state laser medium 1 uses a cylindrical rod in this embodiment, if the distribution of the poor-quality beam is larger than the cross-sectional diameter of the solid-state laser medium 1, the poor-quality beam is applied to the solid-state laser medium 1. The irradiated part is reduced. Therefore, as shown in FIG. 7, when the solid-state laser medium 1 is arranged at a position close to the output mirror 5, the overlap between the low-quality beam and the solid-state laser medium 1 is reduced, and the amplification of the low-quality beam is weakened. Amplification of a good beam becomes dominant.

Further, by making the total reflection mirror 4 a convex mirror as shown in FIG. 8, the beam diameter inside the resonator can be increased. As the beam diameter increases, the poor quality beam becomes weaker, while the good quality beam becomes more dominant, and the quality of the laser beam is improved.

As described above, with the configuration in which the total reflection mirror 4 is a convex mirror and the output mirror 5 is a concave mirror, a high quality laser beam output can be obtained compactly. However, when the total reflection mirror has a convex surface as in this configuration, output fluctuation due to the displacement of the mirror increases.

FIG. 9 is a schematic view showing the positional relationship between the output of the concave mirror 5 and the total reflection mirror 4 of the convex mirror. In the figure, members such as a solid laser medium are not shown. The center of curvature of each mirror is shown in the same figure. In an ideal case where the output mirror 5 and the total reflection mirror 4 do not have any deviation in inclination, the optical axis of the resonance beam in the resonator and the center of curvature of each mirror are located on the same line. In the figure, the direction of the optical axis of the resonance beam in the ideal state is indicated by a chain line. The resonance optical axis position on the output mirror 5 A, a resonance optical axis position on the total reflection mirror 4 is B, also the center of curvature of the output mirror 5 O _A, the center of curvature of the total reflection mirror 4 and O _B I do. As described above, the curvature of the convex lens is smaller than the curvature of the concave lens, and the curvature of the output mirror 5 is longer than the length of the resonator (the distance from the output mirror 5 to the total reflection mirror 4). Therefore, the center of curvature O _A of the output mirror 5 is not on the line A-B, is located on the right side of the B in FIG.

FIG. 10 shows a state in which the output mirror 5 is inclined by θ. In this case, the center of curvature of the output mirror 5 is O
Shift to _A '. Since the resonance of the laser beam resonates on a line connecting the centers of curvature of the mirrors, the optical axis of the resonance shifts to A′-B ′. If the curvature of the total reflection mirror 4 is reduced, the center of curvature O _B of the total reflection mirror 4 is shifted to the left in the figure, since the O _B approaches the center of curvature O _A of the words and the output mirror 5, the slope of the output mirror 5 , The deviation of the resonance optical axis becomes large.

FIG. 11 shows a state in which the total reflection mirror 4 is tilted by θ, contrary to the above. In this case, the center of curvature of the total reflection mirror 4 is shifted to O _{B 'as} shown in FIG. Since the curvature of the total reflection mirror 4 is smaller than the curvature of the output mirror 5, the deviation amount of the center of curvature is smaller even with the same inclination as compared with the case where the output mirror 5 in FIG. For this reason, the shifted optical axis A ″
It can be seen that the shift amount of −B ″ is smaller than A′−B ′.

If the beam diameter is increased to improve the beam quality, the curvature of the convex surface of the total reflection mirror 4 is reduced. As a result, the output mirror 5
, The amount of shift of the resonance optical axis increases. For this reason, it can be said that making the azimuth adjustment of the output mirror 5 accurate is more important than that of the total reflection mirror 4.

As described above, since the inclination of each mirror greatly affects the output of the laser beam, it is necessary to adjust the angle, that is, the inclination of the mirror when using a laser oscillator. FIGS. 12 and 13 show a mechanism for adjusting the mirrors 4 and 5 in the conventional laser oscillator. In these figures, as described above, the distance and the size between the mirrors are exaggerated for explanation, and do not show the actual size. Each mirror shown in these figures is provided with adjusting screws 7 and 8 as an inclination adjusting mechanism.

The adjusting screws 7 and 8 are provided at one position or two or more positions at eccentric positions on the rear surface of the mirror. The joints 30, 3 are located on the opposite sides of the adjusting screws 7, 8 and substantially opposite to the adjusting screws 7, 8 with respect to the center of the mirror.
1 is provided. The joints 30 and 31 are connected so that the mirror can be freely deflected about this point. The joints 30 and 31 are provided at one place on the back of the mirror.
It is also possible to adopt a configuration provided at three places.

The adjusting screws 7 and 8 and the joints 30 and 31
The mirror tilt adjusting mechanism is configured so that the rear surface of the mirror is pushed out by the advancement of the adjusting screws 7 and 8 so that the tilt can be adjusted. Also, even if the adjusting screws 7 and 8 are retracted, the mirror can be elastically changed to the adjusting screws 7 and 8 so that the rear surface of the mirror can follow the adjusting screws 7 and 8 while contacting the tip thereof to change the tilt of the mirror. An elastic mechanism for pressing, a mechanism for connecting the tip of the adjusting screw to the back of the mirror, or the like is employed. As these mechanisms can use known mechanisms as appropriate,
Not shown.

In the laser oscillator having such a configuration, the influence of the inclination of the output mirror 5 is particularly large, so that a strict inclination adjustment operation is required at the site of use. In addition, the adjustment position is not limited to the output mirror 5, and the positioning operation is similarly required for the total reflection mirror 4, and other portions to be adjusted cover the entire apparatus. For this reason, even if the output mirror 5 is adjusted optimally, the optimal position of the output mirror 5 may fluctuate while adjusting other parts, and readjustment is required, which requires more time and effort.

In order to simplify such a complicated adjustment operation, it is necessary to narrow down a portion to be adjusted. Specifically, one of the mirrors is fixed, and only the other is adjusted so that fine adjustment is possible.

The optical axis of the laser output is determined by the positional relationship between the center axis of the output mirror and the solid-state laser medium.
For this reason, an output mirror serving as a reference for determining the optical axis direction of the laser output light is fixed. In the first embodiment of the present invention, the output mirror 5 side, which is located near the solid-state laser medium 1 and is sensitive to changes in direction and angle, is fixed. FIG. 14 and FIG.
FIG. 5 shows the configuration of the laser oscillator according to the first embodiment of the present invention. As shown in this figure, the output mirror 5 is completely fixed on the base 9 without the tilt adjusting mechanism, and the angle of the total reflection mirror 4 can be adjusted by the adjusting screw 7. The output mirror 5 is fixed on the base 9 after the position, direction and inclination of the output mirror 5 are adjusted accurately. The base 9 is fixed on the oscillator base 12. With this configuration, only one of the total reflection mirrors 4 can be tilted, so that only this portion can be adjusted to finely adjust the optical axis.

In general, when the optical axis of the laser output light coincides with the central axis of the solid-state laser medium 1, the efficiency increases. The optical axis of the laser output light is determined by the positional relationship and the inclination of the central axis of the output mirror 5 with respect to the central axis of the solid-state laser medium 1. If the positions and inclinations of the solid-state laser medium 1 and the output mirror 5 are stable, the output will be stable.

Further, in this embodiment, the output mirror 5 is arranged at a place where the temperature is stable. That is, the base 9 for fixing the output mirror 5 is provided close to the circulation path 10 of the cooling medium. If the temperature of the fixed portion is kept constant, the output stability will be higher. Therefore, it is possible to avoid a situation in which the temperature of the apparatus becomes high due to a change in environmental temperature or the use of a laser oscillator, and the metal is deformed and the angle of the mirror is shifted. As the cooling mechanism, equipment for cooling the solid-state laser medium 1 or the like can be used together. In the figure, arrows indicate the direction in which the cooling medium flows. As a cooling medium, cooling water or cooling gas can be used. Further, a cooling mechanism different from that for the solid-state laser medium 1 and the excitation light source 2 may be provided.

As an example, in FIGS. 14 and 15, the base 9 is maintained at a constant temperature by cooling water for cooling the solid-state laser medium 1. By fixing the output mirror 5 thereon, the temperature fluctuation of the output mirror fixing portion can be reduced with respect to the fluctuation of the environmental temperature, so that the tilt fluctuation can be suppressed and the output can be stabilized. The flow path of the cooling water is made even more uniform by passing immediately below or near the fixed portion of the output mirror. Even if the cooling water channel is not located near the fixed portion of the output mirror, if the cooling water channel is disposed on the base 9 or a member in contact with the base, the same effect is obtained because the temperature of the entire base 9 strongly depends on the cooling water temperature. Can be expected. For example, although not particularly shown, the same effect can be obtained by passing cooling water through an oscillator base or a laser marker base and fixing an output mirror therethrough.

In this configuration, the output mirror 5 is stable and hardly affected by the environmental temperature. Therefore, only one of the total reflection mirrors 4 fluctuates, and fine adjustment can be easily performed by the adjusting screw 7, maintenance can be easily performed, and the mirror can be used stably.

Further, in the second embodiment of the present invention, as shown in FIGS. 16 and 17, members constituting a laser resonator are sealed in a housing 11. FIG. 16 is a side view of the housing 11, and FIG. 17 is a cross-sectional view thereof. There are various situations where a laser oscillator is used. For example, in a situation where a laser oscillator is used in a factory line, the environment becomes a lot of dust and oil.
Under such conditions, oil may enter the interior of the apparatus during maintenance work, and may adhere to the mirror and contaminate the optical system. Therefore, in this embodiment, in order to prevent such an adverse effect, the main body of the laser oscillator is housed in the housing 11 and completely sealed from the outside to protect the apparatus from oil vapor and moisture.

FIG. 17 shows the interior of a housing 11 which contains members such as a total reflection mirror 4 and a solid-state laser medium and an output mirror (not shown). Since the output mirror 5 side of this laser oscillator is fixed as described above, the only necessary adjustment is adjustment of the total reflection mirror 4. The oscillator base 12 is fixed to the laser marker base 1 by the fixing portion 29.
3 is fixed. The fixing portion 29 is fixed with a screw or the like at a substantially central portion in the extending direction of the oscillator base 12 and the laser marker base 13.

Further, the oscillator base 12 is connected to the laser marker base 13 via one or more stabilizing mechanisms 25. In the embodiment shown in FIG.
2 near the center of the laser marker base 1 with the fixing part 29
3 and are connected by providing stabilizing mechanisms 25 on both left and right sides. Three or more stabilizing mechanisms 25 can be provided,
Alternatively, a configuration may be adopted in which the fixing portion 29 and the stabilizing mechanism 25 are provided at positions where the oscillator base 12 is divided into three equal parts.

The stabilizing mechanism 25 shown in FIG.
, Screws 27 and separator 14. The screw 27 has a flange 27a at one end. Screw 27 is spring 2
6, and the tip is fixed to the laser marker base 13 through an insertion hole 12a provided in the oscillator base 12. The spring 27 has a spring-like shape, and can pass the screw 27 in diameter, and has a flange 27a and an insertion hole 12a.
Greater than. The size of the insertion hole 12a is
Can be passed in the vertical direction with respect to the oscillator base 12, and the screw 27 can be slightly inclined from the vertical direction with respect to the oscillator base 12.

The oscillator base 12 and the laser marker base 13 are separated by a separator 14.
It is pressed by the spring 26 and is stable. Due to the configuration in which the spring 26 is sandwiched between the flange 27 a and the oscillator base 12, the oscillator base 12 is pressed toward the laser marker base 13 by the elastic force of the spring 26. In other words, the oscillator base 12 and the laser marker base 13 are fixed by one fixing part 29 but are not fixed by the stabilizing mechanism 25, and the spring 26 absorbs the inclination of the laser marker base 13 to resonate. The container base 12 is stabilized. With this configuration, even if the plate is distorted due to, for example, tightening of the plate mounting screw of the laser marker base 13, the distortion is absorbed by the spring 26, so that the distortion is not propagated to the oscillator base 12 and stabilized.

Further, since the resonator base 12 and the laser marker base 13 are not in direct contact with each other, there is also an effect of suppressing heat conduction, and it is possible to suppress metal distortion due to heat. Thus, the oscillator base 12 is thermally and stress-insulated from the laser marker base 13. However, the present invention does not limit the configuration of the stabilizing mechanism to the configuration shown in FIG. For example, a stabilizing mechanism using a leaf spring or a configuration in which the stabilizing mechanism is arranged not in a straight line but in a triangular shape may be adopted.

The angle of the total reflection mirror 4 shown in FIG. The adjustment screw 7 of the total reflection mirror 4 can be adjusted by inserting an adjustment driver 16 or a hexagon wrench from an operation window 15 provided on the rear surface of the housing 11, and can be adjusted while maintaining a sealed state. is there. When not used, the operation window 15 into which the adjustment driver is inserted is closed with a screw or the like, and the inside is completely sealed. A path from the adjustment driver operation window 15 to the adjustment screw 7 is provided with a cylindrical guide 28 to perform dustproof processing, thereby preventing external dust and the like from entering the inside of the laser oscillator.

In the laser oscillator having this configuration, it is not necessary to open the apparatus to expose the inside for adjusting the total reflection mirror 4. Since the angle can be adjusted by inserting the adjustment driver 16 from the back of the total reflection mirror 4 with the casing 11 sealed, dust and dirt can be prevented from entering during maintenance work, and the optical It has the advantage that it can be adjusted without polluting the system.

Next, a laser oscillator according to a third embodiment of the present invention will be described. In this example, an optical system that obtains parallel laser light having an arbitrary beam diameter as a laser output is used.

Conventionally, a beam expander including a plano-convex lens 19 and a plano-concave lens 18 as shown in FIG. 17 was used. In FIG. 18, a laser output obtained from a resonator constituted by a meniscus lens 5A as an output mirror 5 and a plano-concave lens 4A as a total reflection mirror 4 is emitted from an output mirror 5 to an output mirror 19. Output mirror 5
The laser light output from the meniscus lens 5A is a parallel light. This parallel light is a parallel light having a magnification determined by the focal length of the concave lens 18 and the focal length of the output mirror 19.

In this configuration, two or more mirrors are required to configure the beam expander 17. For this reason, the total length of the optical system constituted by the laser oscillator and the beam expander 17 becomes longer, the device becomes larger, and the use of a plurality of mirrors increases the cost.
Further, since the beam expander 17 is constituted by two mirrors, it is necessary to adjust the two mirrors without deviation from the optical axis in order to obtain a desired output for the expanded laser light. For this reason, the number of adjustment points for adjusting the optical axis and the direction of the laser increases, and there is a problem that it is complicated and time-consuming.

To solve this problem, the third embodiment of the present invention
The laser oscillator according to the embodiment uses a double-sided concave lens 5B as the output mirror 5, as shown in FIG. With this configuration, the cost can be suppressed by using one mirror of the beam expander 17, and the operation of adjusting the optical axis can be simplified. Furthermore, the feature that the laser oscillator can be made compact by shortening the total length of the optical system is also realized.

FIG. 18 shows a conceptual diagram of a conventional laser oscillator using a concave mirror resonator. The pair of laser resonator mirrors facing each other with the solid-state laser medium 1 interposed therebetween is concave in this example. The curvature of the exit side of the output mirror 5, that is, the left side of the meniscus lens 5A in the figure is smaller than the curvature of the concave surface of the inner surface (the right side of the meniscus lens 5A in the figure) constituting the resonator so that the emitted laser light becomes parallel light. The convex surface has a small curvature. The laser beam emitted from the laser oscillator having this configuration has a predetermined beam diameter determined by the shape of the mirror constituting the resonator and the shape of the solid-state laser medium.

In order to convert this into a desired beam diameter, the conventional example of FIG. 18 uses a beam expander 17. The beam expander 17 shown in this example has a constant magnification composed of a plano-concave lens 18 and a plano-convex lens 19.
Here, the magnification is determined by the focal length of the plano-concave lens 18 and the focal length of the plano-convex lens 19. Fine adjustment of the beam divergence angle is performed by finely adjusting the distance between the two mirrors.

On the other hand, in the laser oscillator according to the third embodiment of the present invention shown in FIG. 19, the output side of the output mirror 5 has a concave surface, so that the light emitted from the laser oscillator has a concave curvature. With a configuration in which divergent light having a determined divergence angle is converted into parallel light by the plano-convex lens 19,
Obtain parallel laser light. That is, the step of temporarily converting the output light from the resonator into parallel light is omitted.

The beam diameter is determined by the divergence angle determined by the curvature of the concave surface on the output side of the output mirror 5 (the left side of the double-sided concave lens 5 B in the figure) and the focal length of the plano-convex lens 19. Fine adjustment of the spread angle is performed by the plano-convex lens 19.
And the output mirror 5.

In this embodiment, the output side (the double-sided concave lens 5) of the output mirror 5 constituting the beam expander 17 is used.
B left side) is illustrated as a concave surface. However, the shape is not limited to a concave surface, and may be a flat surface, a convex surface, or the like according to a required beam diameter, the total length of the beam expander 17, the focal length of a convex lens included in the beam expander 17, and the like.
On the other hand, as for the shape of the total reflection mirror 4, a flat surface, a convex surface, or the like can be realized in addition to the concave surface illustrated.

As described above, the laser oscillator according to the third embodiment shown in FIG. 19 has a configuration in which the output light from the resonator is directly provided with a desired laser beam diameter by one mirror, and is composed of two or more lasers. The cost is reduced by reducing the number of mirrors of the beam expander 17 to one, and the optical axis can be adjusted only by adjusting one mirror, so that the maintenance work can be simplified. Further, since the total length of the optical system including the laser oscillator and the beam expander can be shortened, the apparatus can be downsized. As described above, there is an advantage that not only the maintenance of the device is facilitated, but also the price and the size can be reduced.

Further, a laser oscillator according to a fourth embodiment of the present invention will be described with reference to FIGS. The laser oscillator shown in these figures is provided with a laser pointer for indicating a work position such as printing and processing.

The laser pointer uses a laser diode (LD) or the like and is used by a laser processing device such as a laser marker for checking before work. Y
In the case of a laser marker using an invisible light laser such as an AG laser, a laser pointer using an LD laser beam, which is visible light, is irradiated on an actual work target before performing a marking operation. When the LD laser light of the laser pointer moves at high speed along the actual printing pattern, etc., the trajectory of the light leaves an afterimage, so the printing position is pointed,
You will be able to see it. Based on this trajectory pattern,
The actual print position can be adjusted or confirmed.

FIG. 20 shows a conventional laser oscillator having a laser pointer. The laser pointer shown in this figure includes a pointer LD 20 and an LD collimating lens 2.
1 and a visible light reflection-infrared light transmission mirror 22. The LD laser light emitted from the pointer LD 20 is collimated by the collimator lens 21, that is, collimated, and reflected by the visible light reflection-infrared light transmission mirror 22. The visible light reflection-infrared light transmission mirror 22 is a half mirror that passes the laser beam light but reflects the LD laser light, and is arranged with the marking laser and the optical axis aligned.

This laser pointer inputs the LD laser light from the position shown by the solid line in FIG. 20 before the beam expander 17. The input LD light passes through a plano-concave lens 18 and an output mirror 19 constituting a beam expander 17, is deflected by an X-direction deflecting mirror and a Y-direction deflecting mirror, and follows the same path as the marking laser to obtain Fθ.
The light is emitted from the lens 6. The laser oscillator of FIG.
A galvano motor 23 for the X-direction deflecting mirror for driving the X-direction deflecting mirror and the Y-direction deflecting mirror for deflecting the laser, respectively;
4 is illustrated.

Alternatively, the laser pointer may be arranged at the position shown by the broken line in FIG. 20, and the LD laser light may be input from the subsequent stage of the beam expander.

In the method shown in FIG. 20, the visible light reflection-infrared transmission mirror 22 and the LD collimating lens are used to accurately match the optical axis of the LD laser light with the optical axis of the marking laser and adjust the focal position. 21, LD20 for pointer
Must be adjusted with high precision. Further, since optical members such as the visible light reflection-infrared transmission mirror 22 and the LD collimator lens 21 are used, there is a problem that the cost is increased.

In the laser oscillator according to the fourth embodiment of the present invention, as shown in FIG. 21, a pointer LD 20 is arranged on the back of the total reflection mirror 4 of the laser oscillator. Since the back surface of the total reflection mirror 4 does not participate in laser oscillation, it can be formed in any shape without any particular limitation. In the present embodiment, an optical system such as a half mirror is omitted by utilizing this characteristic.

The total reflection mirror 4 shown in FIG.
In the figure, the shape on the right side is a shape that functions as a mirror that can collimate the LD light and condense it on the printing surface.
The left side, which is the mirror surface of the total reflection mirror 4, is formed of a dielectric multilayer film having a reflectance of almost 100% at the laser oscillation wavelength. For example, 1 which is the wavelength of the laser output light
A total reflection mirror having a property of reflecting only the light of 064 nm and transmitting the other light transmits almost 100% of visible light whose wavelength is shifted from the oscillation wavelength. According to this configuration, a special mirror for collimating the pointer LD 20 and a half mirror for matching the optical axes are not required. As described above, in the present embodiment, the optical system can be simplified by using the back surface which is not used in the total reflection mirror which is essential for the optical system. Although not shown, the third
The beam expander may be constituted by one mirror as in the embodiment.

As described above, the laser oscillator according to the fourth embodiment of the present invention simplifies the adjustment work by simplifying the optical system for the laser pointer, and reduces the cost of the apparatus. I made it. LD2 for pointer
The laser pointer light can be adjusted only by adjusting the position of 0, and the number of adjustment points is reduced by reducing the number of optical members, thereby improving long-term stability.

[0077]

According to the laser oscillator of the present invention, a troublesome adjustment operation is simplified, and a stable laser oscillator which is easy to maintain can be obtained. This is because the laser oscillator according to the first embodiment of the present invention can fix one mirror and adjust the optical axis such as tilt correction using only the other mirror. The output mirror and the total reflection mirror that constitute the resonator have different effects on the output with respect to the tilt. Therefore, the present invention realizes simplification of the tilt adjustment work by fixing the mirror whose sensitivity to the tilt is more sensitive, thereby reducing the number of adjustment points and reducing the necessity of matching with the adjustment of the other mirror. did. As a result, not only the assembling work can be simplified and the work can be performed quickly, but also the maintenance work which has conventionally been complicated can be greatly reduced. This also leads to a reduction in manufacturing and maintenance steps and costs.

Further, in the laser oscillator according to the second embodiment of the present invention, since the output mirror is arranged near the cooling path which is stable in temperature, in addition to the above-mentioned advantages, the occurrence of disorder due to metal deformation due to temperature change is prevented. can do. For this reason, the man-hours required for the assembly and adjustment work can be reduced, and the long-term stabilization of the laser output independent of the environmental temperature can be realized.

Furthermore, in the laser oscillator according to the third embodiment of the present invention, the output of the resonator is made parallel by the laser beam expander and is not made into a desired beam diameter, but is made into parallel light. Is omitted to directly obtain a desired laser beam diameter. This reduces the number of mirrors of the beam expander composed of two or more to one, simplifying the optical axis adjustment work. Furthermore, reducing the number of mirrors can contribute to cost reduction, and the overall length of the optical system including the laser oscillator and the beam expander is shortened, so that the apparatus can be made compact.

Further, in the laser oscillator according to the fourth embodiment of the present invention, the laser pointer is arranged on the back of the total reflection mirror, so that the mirror dedicated to collimate the LD light and the optical axis are matched. The half mirror is omitted. Therefore, the adjustment work is simplified by the reduced number of the optical system members, and the long-term stability is improved.
In addition, the advantages of cutting the manufacturing process by reducing the number of parts and reducing costs by reducing the cost of parts can be enjoyed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a general configuration of a laser oscillator.

FIG. 2 is a schematic diagram showing an intensity distribution according to the quality of a laser beam.

FIG. 3 is a schematic diagram showing a state in which a laser beam is emitted through an output mirror.

FIG. 4 is a schematic diagram showing a state in which a solid-state laser medium is arranged close to an output mirror;

FIG. 5 is a schematic diagram showing a state in which a solid-state laser medium is placed away from an output mirror;

FIG. 6 is a schematic diagram showing the relationship between laser beam quality and distribution.

FIG. 7 is a schematic diagram showing a state in which a solid-state laser medium is arranged in a resonator.

FIG. 8 is a schematic diagram showing a configuration of a laser oscillator using a total reflection mirror as a convex mirror;

FIG. 9 is a schematic diagram showing a resonance optical axis of an ideal resonator in which each mirror has no shift;

FIG. 10 is a schematic diagram showing a resonance optical axis when the output mirror is inclined by θ in the resonator of FIG. 9;

FIG. 11 is a schematic diagram showing a resonance optical axis when the total reflection mirror is inclined by θ in the resonator of FIG. 9;

FIG. 12 is a horizontal sectional view showing an adjusting mechanism of each mirror in a conventional laser oscillator.

13 is a vertical sectional view of the laser oscillator shown in FIG.

FIG. 14 is a horizontal sectional view showing an adjusting mechanism of each mirror in the laser oscillator according to the first embodiment of the present invention.

FIG. 15 is a vertical sectional view of the laser oscillator shown in FIG. 14;

FIG. 16 is a side view showing a housing of a laser oscillator according to a second embodiment of the present invention.

17 is an enlarged sectional view of a main part showing the inside of the housing shown in FIG. 16;

FIG. 18 is a schematic diagram showing a configuration of a beam expander in a conventional laser oscillator.

FIG. 19 is a schematic diagram showing a configuration of an optical system in a laser oscillator according to a third embodiment of the present invention.

FIG. 20 is a schematic diagram showing a configuration of an optical system including a laser pointer in a conventional laser oscillator.

FIG. 21 is a schematic diagram showing a configuration of an optical system including a laser pointer in a laser oscillator according to a fourth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Solid laser medium 2 ... Excitation light source 3 ... Work surface 4 ... Total reflection mirror 4A ... Plano-concave lens 5 ... Output mirror 5A ... Meniscus lens 5B ... Double-sided concave lens 6 ... Ftheta lens 7, 8 ... Adjustment screw 9 ... Base stand 10 ... circulation path 11 ... casing 12 ... oscillator base 12a ... insertion hole 13 ... laser marker base 14 ... separator 15 ... operation window 16 ... adjustment driver 17 ... beam expander 18 ... plano-concave lens 19 ... plano-convex lens 20 ... pointer LD DESCRIPTION OF SYMBOLS 21 ... LD collimating lens 22 ... Visible light reflection-infrared transmission mirror 23 ... Galvano motor for X direction deflection mirror 24 ... Galvano motor for Y direction deflection mirror 25 ... Stabilizing mechanism 26 ... Spring 27 ... Screw 27a ... Flange 28 ... Cylindrical guide 29: fixed part 30, 31, joint part

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5F072 AB01 AK01 JJ01 JJ05 JJ08 KK06 MM08 PP01 PP07 TT01 TT22 YY07

Claims (7)

[Claims] A solid-state laser medium; an excitation light source for exciting the solid-state laser medium; a total reflection mirror positioned on an optical axis of laser light emitted from the solid-state laser medium; A laser mirror including an output mirror facing the total reflection mirror via a solid-state laser medium, the total reflection mirror, and the output mirror, wherein at least the output mirror is provided in the housing. A laser oscillator characterized by being fixed to a table. 2. The laser oscillator according to claim 1, wherein an adjustment mechanism capable of adjusting the angle of the total reflection mirror is provided only on the total reflection mirror side so that the optical axis of the laser beam output can be finely adjusted. . 3. The apparatus according to claim 2, wherein the adjustment mechanism is housed in the housing, and an operation window is provided in the housing so that the adjustment mechanism can be operated from outside the housing. Laser oscillator. 4. The laser oscillator according to claim 3, wherein a cylindrical guide extending from the operation window to the adjustment mechanism is provided in the housing. 5. A laser beam expander for expanding a laser output light output from the output mirror to an arbitrary beam diameter by using the output mirror as a double-sided concave lens. 4. The laser oscillator according to 4. 6. The laser oscillator according to claim 1, further comprising a laser pointer on a back surface of said total reflection mirror. 7. The laser oscillator according to claim 1, wherein a cooling path is arranged near the base.