JP5039122B2 - Variable curvature mirror and optical apparatus using the same - Google Patents

Description

  The present invention relates to a variable curvature mirror for adjusting a focal length, a beam diameter, or a beam mode in an optical apparatus using a laser beam or the like, and an optical apparatus using the variable curvature mirror.

  In an optical device using a laser beam or the like, for example, a laser processing device, the variable curvature mirror can continuously change the shape of the reflecting surface from a flat surface to a concave surface or a convex surface by changing the curvature of the reflecting surface. This is effective because the focal length of the entire optical system, the beam diameter and beam mode in the middle of the optical path or at the processing point can be adjusted.

  However, if the variable curvature mirror simply deforms the reflecting surface shape into a spherical shape that is simply rotationally symmetric, there is a limitation in use such as an incident angle of 10 ° or less due to astigmatism. . As a countermeasure, in the optical pickup device disclosed in Patent Document 1, four piezoelectric elements are used as drive elements, and (curvature in sagittal direction) :( curvature in meridional direction) = 2: 1. That is, by making the ratio of the curvature in the X-axis direction and the curvature in the Y-axis direction of the reflecting surface 1: 2, the spherical aberration at the time of deformation can be corrected even under the reflection condition at an incident angle of 45 °. Possible deformable mirrors have been proposed.

  Further, in the variable curvature mirror disclosed in Patent Document 2, there is proposed a variable curvature mirror that can change the curvature in the sagittal direction and the meridional direction while having only one drive element.

JP 2007-58921 A JP 2009-63887 A

  However, the deformable mirror of Patent Document 1 requires four piezoelectric elements as drive elements, and there is a problem that the piezoelectric elements need to be individually adjusted.

  Moreover, in the variable curvature mirror of the said patent document 2, as shown in FIG. 8, the reflective mirror 40 which has 40 A of reflective surfaces, and the structural member 41 which fixes the back surface 40B of the reflective mirror 40 in four places of the fixed leg 43, Distance changing means 42 having one end fixed near the center of the structural member 41 and the other end fixed near the center of the back surface 40B of the reflecting mirror 40. The center of the back surface 40B is located within the back surface 40B of the reflecting mirror 40. One axis that passes through is defined as the X axis, the axis passing through the center of the back surface 40B in the back surface 40B of the reflecting mirror 40, and the axis orthogonal to the X axis is defined as the Y axis, and the fixing of fixing the back surface 40B of the reflecting mirror 40 of the structural member 41 is fixed. When the four positions of the legs 43 are unequally assigned to the center 40E of the back surface 40B of the reflecting mirror 40 from the X axis and the Y axis, and the distance changing means 42 is driven, the reflecting surface 40A X-axis curvature and Y-axis And the curvature of the direction is to deform the differently reflecting surfaces. In the above technique, the back surface 40B of the reflecting mirror 40 and the structural member 41 are fixed at four positions of the fixing leg 43 in order to suppress the distortion of the reflecting surface 40A of the reflecting mirror 40 and obtain a variable curvature reflecting mirror with less aberration. There is a problem that it is necessary to improve the flatness at the four positions of the fixing leg 43 of the structural member 41 for fixing the back surface 40B of the reflecting mirror 40 and the back surface 40B of the reflecting mirror 40, and for that reason. There was also a problem that the manufacturing cost was high.

  The present invention has been made to solve the above-described problem, and does not require improvement in the accuracy of the length and flatness of the support legs that support the reflecting mirror, and is a simple method with one drive element. It is possible to change the curvature between sagittal and meridional directions, and to provide a variable curvature mirror that can adjust the focal length, beam diameter, and beam mode without causing distortion of the reflecting surface. Yes.

  In order to solve the above problems, a variable curvature mirror according to the present invention includes a reflecting mirror, a structural member arranged at a distance from the back surface of the reflecting mirror, and a reflecting mirror between the back surface of the reflecting mirror and the structural member. A pair of fixing members arranged with the center of the back surface of the mirror and one pair of reflecting members supported by one end being fixed to the back surface of the reflecting mirror and the other end being fixed to the fixing member by two One end of the leg is fixed to the opposite side of the intermediate position of the fixing member to which each pair of reflecting mirror supporting legs is fixed, and the other end is fixed to the structural member, and one end is the back surface of the reflecting mirror Distance changing means fixed near the center and the other end fixed to the structural member, and when the distance changing means is driven, the reflector support leg is placed at a position where the curvature of the reflecting surface of the reflector is changed. It is characterized by the arrangement.

  The optical device according to the present invention is characterized in that the above-described variable curvature mirror is used as a reflecting mirror.

  According to the variable curvature mirror according to the present invention, there is an effect that the focal length, the beam diameter, and the beam mode can be adjusted easily and inexpensively.

  The optical device according to the present invention is advantageous in that an optical device can be obtained that is inexpensive and can easily adjust the focal length, the beam diameter, and the beam mode.

FIG. 3 is an assembly diagram illustrating the structure of the variable curvature mirror in the first embodiment. FIG. 6 is a diagram for explaining an operation concept of the variable curvature mirror in the first embodiment. FIG. 3 is a diagram illustrating a protrusion formed on a reflecting mirror support leg or a fixing support leg in the first embodiment. FIG. 3 is an assembly diagram when a circular seat is provided on the back surface of the circular reflecting mirror of the variable curvature mirror in the first embodiment. It is a figure which shows the shape of the other circular seat in Embodiment 1. FIG. FIG. 6 is an assembly diagram illustrating the structure of a variable curvature mirror according to the second embodiment. 6 is a configuration diagram of an optical device using a variable curvature mirror in Embodiment 3. FIG. It is an assembly drawing explaining the structure of the curvature variable mirror in a prior art example.

  Hereinafter, a variable curvature mirror according to an embodiment of the present invention will be described with reference to FIGS.

Embodiment 1 FIG.
FIG. 1 is an assembly diagram illustrating an outline of the variable curvature mirror according to the first embodiment.
In FIG. 1, the variable curvature mirror 1 includes a circular reflecting mirror 2, a structural member 3 arranged at a distance from the back surface 2 </ b> B side of the circular reflecting mirror 2, and a back surface 2 </ b> B of the circular reflecting mirror 2 and the structural member 3. A pair of fixing members 4 arranged with the center of the back surface 2B in between, one end is fixed perpendicularly to the back surface 2B of the circular reflector 2, and the other end is fixed to the fixing member 4 as a pair. Two pairs of reflecting mirror support legs 5, one end fixed to an intermediate position of the fixing member 4, the other end fixed to the structural member 3, and the vicinity of the center of the back surface 2 </ b> B of the circular reflecting mirror 2. The piezoelectric actuator 7 is a distance changing means having one end fixed to the structural member 3 and the other end fixed to the structural member 3.

  Here, when a certain axis passing through the center 2E of the back surface 2B of the circular reflecting mirror 2 is defined as the X axis, the axis passing through the center 2E and orthogonal to the X axis is defined as the Y axis, the angle formed with the X axis is 36.5. In the vicinity of the four points 2D where the two axes 2C having an angle of 53.5 ° with the Y axis intersect the outer circumference circle, the reflector support leg 5 is screwed perpendicularly to the back surface 2B. It is fixed by attaching or bonding. The structural member 3 has substantially the same outer diameter as the circular reflecting mirror 2, and the lengths of the four reflecting mirror support legs 5 are substantially the same. The bottom surface 5B of the reflecting mirror support leg 5 and the top surface 4A of the fixing member 4, the bottom surface 4B of the fixing member 4, the top surface 6A of the fixing portion support leg 6, the bottom surface 6B of the fixing member support leg 6, and the top surface 3A of the structural member 3 Is fixed by screwing, brazing, or bonding.

Next, the operation of the variable curvature mirror in the first embodiment will be described with reference to FIG.
The pair of fixing members 4 sandwich the piezo actuator 7 which is a distance changing means, and both end surfaces of the piezo actuator 7 are joined to the center 2E of the circular reflecting mirror 2 and the center 3B of the structural member 3, respectively. The total length of the reflector support leg 5, the thickness of the fixing member 4, and the length of the fixing member support leg 6 is set to be substantially the same as the middle of the operating range of the piezo actuator 7. Here, when a voltage is applied to the piezo actuator 7 and the length of the piezo actuator 7 is shortened, a load in a direction in which the back surface 2B of the circular reflector 2 is pushed by the reflector support legs 5 at four points near 2D. A load in the direction of pulling the circular reflecting mirror 2 is generated in the vicinity of the center 2E of the back surface 2B, and the reflecting surface 2A is deformed into a concave shape having a curvature ratio of about 2: 1 between the X-axis direction and the Y-axis direction. Can do. On the contrary, when the length of the piezo actuator 7 is increased, the load in the direction in which the back surface 2B of the circular reflecting mirror 2 is pulled at four points near 2D by the reflecting mirror support leg 5 and the circular shape near the center 2E of the back surface 2B. A load in the direction of pressing the reflecting mirror 2 is generated, and the reflecting surface 2A can be deformed into a convex shape having a curvature ratio of about 2: 1 between the X-axis direction and the Y-axis direction. The load applied to the center 2E of the back surface 2B of the circular reflecting mirror 2 is four times the load in 2D applied by the reflecting mirror support leg 5. Thereby, even when the incident angle of the light beam is 45 °, it is possible to realize the curved deformable mirror 1 that can change the curvature of the reflecting surface 2A without generating aberration.

  In the above description, the case where the reflection support leg 5 is arranged at a position that forms an angle of 36.5 ° with respect to the X axis has been described. However, the reflection support leg fixed to the back surface 2B of the circular reflection mirror 2 is described. If the angle between the four points 5 and the X-axis is 30 ° to 40 °, the ratio of the curvature in the X-axis direction and the curvature in the Y-axis direction is determined by the circular reflector 2 with respect to the incident angle 45 ° of the light beam. Therefore, the variable curvature mirror 1 can be deformed so as to be approximately 2: 1 and the aberration can be reduced. In addition, although the position of the reflective support leg 5 was demonstrated by the angle with respect to an X-axis, even if it replaces an X-axis and a Y-axis, it is the same.

  In the above-described structure, for example, as shown in FIG. 2, even when one reflector support leg 5 is present and a reflector support leg 5C longer than the length of the other reflector support leg 5 exists. One of the fixing members 4 is inclined, and the height of the bottom surface 6B of the two fixing member supporting legs 6 is different from this inclination, so that the structural member 3 is inclined, but distortion occurs in the reflecting surface 2A of the circular reflecting mirror 2. There is nothing to do. Regarding the correction of the inclination of the structural member 3, the inclination of the structural member 3 can be corrected by configuring the variable curvature mirror 1 as a tiltable holder.

  Further, even if there is a difference in the height of the back surface 2B of the circular reflecting mirror 2, a difference in the thickness of the fixing member 4, a difference in the length of the fixing member support leg 6, or a difference in the height of the end surface 3A of the structural member 3. It is the same. The material and thickness of the circular reflector 2, the fixed member 4 and the structural member 3, the material of the reflector support leg 5 and the fixed member leg 6, the cross-sectional shape, the cross-sectional area, etc. must be damaged by the appropriate uneven deformation. For example, any method may be selected and set.

In other words, moderate uneven deformation occurs in the shape of the top surface 6A and the bottom surface of the reflector support leg 5 and the fixing member support leg 6 perpendicular to the top surface and the bottom surface, and the curvature of the circular reflector 2 is changed in the selected joining method. It is sufficient if the joint surface does not peel off against the load to be applied. For example, as shown in FIG. 3A, a circular reflecting mirror is provided by providing minute square convex projections 8 on the top surfaces 5A and 6A and the bottom surfaces 5B and 6B of the reflecting mirror support leg 5 and the fixing member leg 6. 2. Distortion caused by the flatness of the fixed member 4 and the structural member 3 can also be absorbed, and a variable curvature mirror that suppresses the occurrence of aberrations can be provided. Further, as shown in FIG. 3B, the protrusions provided on the top surfaces 5A and 6A and the bottom surfaces 5B and 6B of the reflector support legs 5 and the fixing member legs 6 are the same even if they are hook-shaped protrusions 9. Can be expected.

  If the rigidity of the fixing member 4 or the structural member 3 is reduced, such as by reducing the thickness of the fixing member 4 or the structural member 3, the degree of deformation of the circular reflecting mirror 2 with respect to the change in distance by the piezo actuator 7 is reduced, and the circular reflection is reduced. A finer control of the change in curvature of the mirror 2 can be expected.

  Further, as shown in FIG. 4, a circular seat 10 is provided between the circular reflecting mirror 2 and the piezo actuator 7, and the circular reflecting mirror 2 and the piezo actuator 7 are joined to both end faces 10A and 10B of the circular seat 10, respectively. To do. By changing the diameter of the circular seat 10, the shape of the X-axis direction cross section 2X and the Y-axis direction cross section 2Y of the reflecting surface 2A at the time of deformation can be changed. More preferably, as shown in FIG. 5A, a counterbore process is applied to the vicinity of the center of the circular seat 10 on the surface 10A side, and the circular reflector 2 is joined in an arc shape. Alternatively, as shown in FIG. 5B, three or more legs 10 </ b> C may be provided on the surface 10 </ b> A side of the circular seat 10.

  Thereby, the deformation | transformation shape of the circular reflecting mirror 2 can be made into the curved surface shape connected more smoothly and continuously in the inside and the outside of the diameter of the circular seat 10. FIG. By appropriately setting the diameter of the circular seat 10, the cross-sectional shape in the X-axis direction and the Y-axis direction can be changed, and in particular, it can be made close to an ellipse or a circle. The circular seat 10 and the leg 10C may be formed integrally or may be formed by joining those formed as separate parts. Further, the circular seat 10 and the circular reflecting mirror 2 may be formed from the same material by cutting or the like. Furthermore, although the circular seat 10 has been described as circular, it may be oval. The above also applies to other embodiments described later.

  Since the piezo actuator 7 can be controlled continuously in time, for example, in a laser processing apparatus, an effect of adjusting the focus position can be expected even when the focus position needs to be changed during laser processing.

  As described above, in the variable curvature mirror according to the first embodiment, the fixing member is provided between the back surface of the reflecting mirror and the structural member, and the reflecting mirror support leg and the fixing member support leg are respectively installed, and the two fixing member support legs are provided. And the distance changing means support the entire reflector, so that the curvature of the reflector can be made variable by suppressing the occurrence of aberrations even if the processing accuracy of the components is low. There is a remarkable effect that the distance, beam diameter, and beam mode can be adjusted.

Embodiment 2. FIG.
FIG. 6 is an assembly diagram illustrating the structure of the variable curvature mirror according to the second embodiment.
The variable curvature mirror according to the second embodiment uses a screw member as a distance changing means instead of the piezo actuator in the variable curvature mirror according to the first embodiment.

  In FIG. 6, instead of the piezo actuator 7 of FIG. 4 of the first embodiment, a screw member 11 in which male threads having different pitches are formed at both ends is used. At the center of the surface 10B of the circular seat 10, a female screw 10F that is screwed into the male screw 11A on one side of the screw member 11 is provided. In addition, a female screw 3 </ b> F that engages with the male screw 11 </ b> B on the other side of the screw member 11 is provided at the center of the structural member 3. The same reference numerals as those in the first embodiment shown in FIGS. 1 and 4 indicate the same or corresponding parts, and the description of the same components is omitted.

  Next, the operation of the second embodiment will be described. Since the pitches of the male screws 11A and 11B at both ends of the screw member 11 are different, the interval between the circular reflecting mirror 2 and the structural member 3 can be changed by rotating the screw member 11 left or right. As a result, similarly to the case where the piezo actuator 7 is used, it is possible to realize the variable curvature mirror 1 having a curvature different in the X-axis direction and the Y-axis direction on the reflecting surface 2A of the circular reflecting mirror 2.

  As in the first embodiment, if the angle between the position of the reflector support leg 5 and the X axis is 36.5 °, the ratio of the curvature in the X axis direction to the curvature in the Y axis direction is approximately 2: 1. The reflecting surface 2A can be deformed into a concave shape or a convex shape. Even if the screw member 11 is used, the reflection of the circular reflecting mirror 2 can be performed by setting and design and manufacturing the movable range of the screw member 11 so that it can be deformed as necessary on both the concave side and the convex side. The surface 2A can be freely deformed into irregularities, and the focal length of the entire optical system, the middle of the optical path, or the beam diameter and beam mode at the processing point can be adjusted.

  When it is not necessary to control the curvature of the reflector continuously in time, the length of the screw member 11 or the like can be adjusted instead of the piezo actuator 7 as shown in the second embodiment, and the length A distance changing means that can maintain the distance is effective. The male screws 11A and 11B at both ends of the screw member 11 need only have a predetermined pitch difference, and the pitch difference may be generated by a combination of a right screw and a left screw. If the pitch difference is reduced, it becomes easy to finely adjust the unevenness of the circular reflecting mirror 2. Further, any other mechanism can be used as long as the distance can be changed, and the curvature of the reflecting mirror can be adjusted.

  Thus, according to the variable curvature mirror according to the second embodiment, as a distance changing means, a seat in which an internal thread is formed on the back surface side of the circular reflecting mirror, a structural member in which an internal thread is formed, and the internal thread are screwed together. Even if the processing accuracy of the component members is low, aberrations can be achieved by providing a screw member with male threads with different pitches at both ends and supporting the entire reflector with two fixing member support legs and distance changing means. The curvature of the reflecting mirror can be made variable by suppressing the occurrence of this, and there is a remarkable effect that the focal length, the beam diameter, and the beam mode can be easily adjusted at a low cost.

  In the second embodiment, the case of using a screw member provided with male screws having different pitches on both sides has been described. However, a screw member provided with female screws having different pitches on both sides is used, and male screws are provided on the circular seat and the structural member side. The same effect can be obtained by providing a screw and engaging with the female screw of the screw member. Further, a circular reflecting mirror and a circular seat may be integrally formed.

  In the first and second embodiments, the variable curvature mirror is circular. However, it is not always necessary to have a circular shape, and it is needless to say that reflection mirrors of other shapes are also applicable.

Embodiment 3 FIG.
Next, an optical apparatus using the variable curvature mirror according to Embodiment 3 will be described. FIG. 7 is a configuration diagram of a laser processing apparatus as the optical apparatus according to the third embodiment. In the third embodiment, a case will be described in which any of the variable curvature mirrors described in the first or second embodiment is applied to a laser processing apparatus in which a plurality of laser beams are passed through one optical system.

In FIG. 7, the laser beam L emitted from the laser oscillator 20 is transmitted by a reflecting mirror 21 in the middle of the optical path and separated into a laser beam M and a laser beam N by a spectroscopic polarizing beam splitter 22. The laser beam M is transmitted to the combining polarization beam splitter 26 by the two sets of reflecting mirrors 23 and the laser beam N is transmitted by the galvano mirror 25 that is rotationally driven by the two sets of galvano scanners 24. Further, the laser beam M and the laser beam N are two-dimensionally scanned by a galvano mirror 28 that is rotationally driven by two sets of galvano scanners 27, and are positioned and irradiated on a workpiece 30 by a condenser lens 29. A square range surrounded by a dotted line on the workpiece 30 is a scannable range 31. The workpiece 30 is placed on a table 32, and the table 32 is configured to be movable in a predetermined range in two dimensions by two table drive mechanisms 33 in the X-axis and Y-axis directions.

  Due to variations in the flatness of the polarizing beam splitter 22, the reflecting mirror 23, the galvano mirror 25, and the combining polarizing beam splitter 26 where the optical paths of the laser beam M and the laser beam N are different, the laser beam M and the laser beam N may cause a difference in focus position. Therefore, the variable curvature mirror 1 of either the first embodiment or the second embodiment is applied to one of the two sets of reflecting mirrors 23.

  Since the incident angle of the laser beam M to the reflecting mirror 23 is 45 °, the X axis is arranged in the sagittal direction and the Y axis is arranged in the meridional direction of the reflecting mirror 23 which is the variable curvature mirror 1. When the focal position of the laser beam M is farther from the condenser lens 29 than the focal position of the laser beam N, if the variable curvature mirror 1 is deformed into a concave shape, the generated laser beam M is suppressed while suppressing the generated aberration. And the focal position of the laser beam N can be matched. When the focal position of the laser beam M is closer to the condensing lens 29 than the focal position of the laser beam N, the laser beam can be suppressed while suppressing the generated aberration by deforming the variable curvature mirror 1 into a convex shape. The focal position of the beam M and the focal position of the laser beam N can be matched.

  In the third embodiment shown in FIG. 7, the case where the variable curvature mirror according to any one of the first or second embodiment is used in the laser processing apparatus is illustrated and described. However, the effect of using the variable curvature mirror is the optical system. Since it acts on the overall focal length, the beam diameter or beam mode in the middle of the optical path or at the processing point, it can also be applied to optical devices other than the laser processing device.

  Further, the laser processing apparatus is not limited to a laser processing apparatus that performs two-dimensional scanning by passing a plurality of laser beams through one optical system. That is, only one laser beam may be used, and the same effect can be obtained even in a laser processing apparatus in which any of the galvano scanners 24 and 27 and the table 32 performs one-dimensional, two-dimensional or three-dimensional scanning or no scanning.

  Further, the laser beam may be any of a single pulse, a plurality of pulses, or continuous oscillation. The processing content is not limited to drilling, and any processing content can be used as long as it can be processed by laser such as cutting, deformation, welding, heat treatment, or marking. Further, any change may be generated in the workpiece as long as it can be generated by a laser such as combustion, melting, sublimation, or discoloration. As described above, according to the laser processing apparatus according to the third embodiment, the focal length and the beam in laser processing can be obtained by using the variable curvature mirror of either the first or second embodiment in the processing optical system. Diameter and beam mode can be adjusted.

  Thus, according to the laser processing apparatus in the third embodiment, by using the curvature variable mirror in any one of the first or second embodiment in the processing optical system, the focal length and the beam diameter in laser processing, There is a remarkable effect that the beam mode can be adjusted.

  In the embodiment described above, the case where the focal length, the beam diameter, and the beam mode in the optical system are adjusted using the variable curvature mirror has been described, but it can also be used to correct the distortion of the reflecting mirror.

  Further, the present invention is not limited to the above-described embodiment, and it goes without saying that these possible combinations are included.

  Moreover, in the figure, the same code | symbol shows the same or an equivalent part.

DESCRIPTION OF SYMBOLS 1 Variable curvature mirror 2 Circular plane mirror 2A Plane surface 3 Structural member 3F, 10F Female screw 4 Fixing member 5 Reflective mirror support leg 6 Fixed member support leg 7 Piezo actuator 8, 9 Protrusion 10 Circular seat 11 Screw member 11A, 11B Male screw 20 Laser oscillator 22 Polarizing Beam Splitter 23 Reflector 26 Combining Polarizing Beam Splitter 30 Workpiece L, M, N Laser Beam

Claims (8)

A reflector,
A structural member disposed at a distance from the back surface of the reflecting mirror;
A pair of fixing members disposed between the back surface of the reflecting mirror and the structural member, with the center of the back surface of the reflecting mirror interposed therebetween,
Two sets of reflecting mirror support legs, one end of which is fixed to the back surface of the reflecting mirror and the other end of which is fixed to the fixing member as a set of two;
A fixed member support leg having one end fixed to the opposite surface of the intermediate position of the fixed member to which each set of reflector support legs is fixed, and the other end fixed to the structural member;
One end is fixed near the center of the back surface of the reflecting mirror, and the other end is fixed to the structural member, distance changing means,
The variable curvature mirror, wherein the reflecting mirror support leg is arranged at a position where the curvature of the reflecting surface of the reflecting mirror is changed when the distance changing means is driven. One axis passing through the back surface center in the back surface of the reflecting mirror is defined as the X axis, the same axis passing through the back surface center in the back surface of the reflecting mirror, and the axis perpendicular to the X axis is defined as the Y axis.
The pair of reflector support legs is in a symmetrical position with respect to the X axis, and the another pair of reflector support legs is with respect to the pair of reflector support legs and the Y axis. 2. The variable curvature according to claim 1, wherein an angle of each of the two pairs of reflector support leg positions with respect to the X axis is 30 ° to 40 °. mirror.   A circular or elliptical seat is provided between the reflecting mirror and the distance changing means, and both end faces of the seat are fixed to the back surface of the reflecting mirror and one end of the distance changing means, respectively. The variable curvature mirror according to claim 1 or 2.   The variable curvature mirror according to any one of claims 1 to 3, wherein a piezo actuator is used as the distance changing means.   The distance changing means is composed of a screw member formed with male screws having different pitches at both ends, and the seat and the structural member formed with female screws that are screwed into the male screws. The variable curvature mirror according to claim 3.   A rectangular, circular or bowl-shaped protrusion is provided on an end surface of the reflecting mirror supporting leg fixed to the back surface of the reflecting mirror and an end surface of the fixing member supporting leg fixed to the structural member, 6. The variable curvature mirror according to claim 1, wherein a protrusion is fixed to each of the back surface of the reflecting mirror and the structural member.   An optical apparatus using the variable curvature mirror according to any one of claims 1 to 6. The optical device positions, irradiates a single-pulse, multiple-pulse, or continuous-wave laser beam on the surface of the workpiece, and burns, melts, sublimates or discolors the workpiece, and cuts, drills, welds, heat-treats, or The optical apparatus according to claim 7, wherein the optical apparatus is a laser processing apparatus that performs processing such as marking.

Images