CN110073251B - Shape-variable mirror and laser processing device - Google Patents

Abstract

The shape-variable mirror (10) comprises: a circular mirror (1) which is a mirror having a reflecting surface; a Y-axis member (4) which is a 1 st member having a Y-axis back plate (4a) as a 1 st plate part and 2Y-axis legs (4b1, 4b2) as 1 st legs; an X-axis member (5) which is a 2 nd member having an X-axis back plate (5a) as a 2 nd plate part and 2X-axis legs (5b1, 5b2) as 2 nd leg parts extending across the 1 st member and abutting against the mirror; a distance changing unit (2) for changing the distance between the 1 st plate and the mirror symmetrically to the distance between the 2 nd plate and the mirror; and a holding member (6) that holds the 1 st member and the 2 nd member. In the reflector, a line segment connecting the portions where the 21 st leg portions are respectively abutted intersects with a line segment connecting the portions where the 2 nd leg portions are respectively abutted.

Description

Shape-variable mirror and laser processing device

Technical Field

The present invention relates to a shape variable mirror and a laser processing apparatus having the same.

Background

Conventionally, a shape variable mirror for correcting wavefront distortion of an optical wave in an optical device is known. Patent document 1 discloses a shape variable mirror including: a mirror having a reflection surface on one side; a 1 st shaft member fixed to 2 locations on the rear surface of the mirror; a 2 nd shaft member having 2 legs fixed to the rear surface of the mirror and spanning the 1 st shaft member; and a distance changing mechanism for changing a distance between the 2 nd shaft member and the 1 st shaft member, wherein a line segment connecting portions for fixing the 1 st shaft member and a line segment connecting portions for fixing the legs of the 2 nd shaft member intersect each other, and the shape variable mirror corrects astigmatism of the light wave using 1 driving element.

Patent document 1: japanese laid-open patent publication No. 2007-171703

Disclosure of Invention

However, according to the above-described conventional technique, the position of the leg of the 2 nd shaft member is changed with respect to the 1 st shaft member which is the reference surface, whereby the shape-variable mirror is deformed, and the center position of the mirror surface is moved with respect to the reference surface in the distance changing direction by the distance changing mechanism. Therefore, there is a problem that the position of the laser beam reflected by the movement of the center position of the mirror surface is shifted.

The present invention has been made in view of the above circumstances, and an object of the present invention is to obtain a shape variable mirror in which a change in the center position of a mirror surface with respect to a member holding the shape variable mirror is suppressed at the time of deformation.

In order to solve the above problems and achieve the object, a shape variable mirror according to the present invention includes: a mirror having a reflective surface; a 1 st member having a 1 st plate portion facing a rear surface of a reflection surface of the reflector, and 21 st leg portions extending from the 1 st plate portion and abutting the reflector; a 2 nd member having a 2 nd plate portion facing the 1 st plate portion, and 2 nd leg portions extending from the 2 nd plate portion across the 1 st member and abutting against the mirror; a distance changing unit for changing the distance between the 1 st plate and the mirror symmetrically with the distance between the 2 nd plate and the mirror; and a holding member that holds the 1 st member and the 2 nd member via the distance changing portion. In the reflector, a line segment connecting the portions where the 21 st leg portions are respectively abutted intersects with a line segment connecting the portions where the 2 nd leg portions are respectively abutted.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, there is an effect that the change of the center position of the mirror surface with respect to the member holding the shape-variable mirror at the time of deformation is suppressed.

Drawings

Fig. 1 is a conceptual diagram for explaining the concept of the shape variable mirror according to embodiment 1.

Fig. 2 is an assembly diagram for explaining the structure of the shape variable mirror according to embodiment 1.

Fig. 3 is a conceptual diagram 1 for explaining a change in shape of the shape variable mirror shown in fig. 2.

Fig. 4 is a conceptual diagram 2 for explaining a change in the shape of the shape variable mirror shown in fig. 2.

Fig. 5 is a conceptual diagram for explaining a change in the shape of the circular mirror included in the variable-shape mirror shown in fig. 2.

Fig. 6 is a conceptual diagram 3 for explaining a change in the shape of the shape variable mirror shown in fig. 2.

Fig. 7 is a conceptual diagram for explaining a change in the shape of a circular mirror included in the variable-shape mirror shown in fig. 2.

Fig. 8 is an assembly diagram for explaining the structure of the shape variable mirror according to embodiment 2.

Fig. 9 is an assembly diagram for explaining the structure of the shape variable mirror according to embodiment 3.

Fig. 10 is an assembly diagram for explaining the structure of the shape variable mirror according to embodiment 4.

Fig. 11 is a conceptual diagram 1 for explaining a shape change of the shape variable mirror shown in fig. 10.

Fig. 12 is a conceptual diagram 2 for explaining a change in shape of the variable shape mirror shown in fig. 10.

Fig. 13 is a conceptual diagram 3 for explaining the shape change of the shape variable mirror shown in fig. 10.

Fig. 14 is a conceptual diagram for explaining a change in the shape of the circular mirror included in the variable-shape mirror shown in fig. 10.

Fig. 15 is an assembly diagram for explaining the structure of the shape variable mirror according to embodiment 5.

Fig. 16 is an assembly diagram for explaining the structure of the shape variable mirror according to embodiment 6.

Fig. 17 is a diagram showing a configuration example of a laser processing apparatus according to embodiment 7.

Detailed Description

Hereinafter, a shape variable mirror and a laser processing apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the present embodiment.

Embodiment 1.

Fig. 1 is a conceptual diagram for explaining the concept of the shape variable mirror according to embodiment 1 of the present invention. Fig. 1 shows a circular reflecting mirror 1 included in a variable geometry mirror according to embodiment 1 of the present invention. The circular mirror 1 shown in fig. 1 has a mirror surface 1sf and a back surface 1sb which are reflection surfaces for reflecting light, and the mirror surface 1sf and the back surface 1sb are circular and are planes parallel to each other. As shown in fig. 1, the mirror surface 1sf defines an X axis which is a 1 st axis passing through the center of the outer circumference of the mirror surface 1sf and a Y axis which is a 2 nd axis orthogonal to the X axis and intersecting with the center of the outer circumference. On the back surface 1sb, a Yb axis, which is a 2 nd axis parallel to the Y axis and intersecting an axis parallel to the X axis at the center of the outer circumference circle of the back surface 1sb, is defined. In addition, a Z-axis forming a left-hand coordinate system together with the X-axis and the Y-axis is defined. Among the Z-axis directions, a direction from a holding member 6 shown in fig. 2 described later toward the circular mirror 1 is defined as a + Z direction, and a direction opposite to the + Z direction is defined as a-Z direction.

A load Fb1 in the + Z direction, which is a direction of pressing perpendicular to the back surface 1sb, is applied to the Yb axis intersection Pyb1, which is an intersection of the Yb axis and the outer circumference of the back surface 1sb, and a load Fb2 in the + Z direction, which is a direction of pressing perpendicular to the back surface 1sb, is applied to the Yb axis intersection Pyb2, which is the other intersection. On the other hand, at an X-axis intersection Pxf1 which is an intersection of the outer peripheral circle of the mirror surface 1sf and the X axis, a load Ff1 in the-Z direction is applied so as not to move in the + Z direction with respect to the mirror surface 1sf, and at another intersection, an X-axis intersection Pxf2, a load Ff2 in the-Z direction is applied so as not to move in the + Z direction with respect to the mirror surface 1 sf. If a load is applied as described above, the mirror surface 1sf of the circular mirror 1 is deformed in a saddle shape. Specifically, the saddle shape is a convex shape in which the center of the mirror surface 1sf is convex on a straight line parallel to the X axis, and a concave shape in which the center is concave on a straight line parallel to the Y axis. The convex curve shape on the X axis and the concave curve shape on the Y axis are the same shape with opposite directions.

If the focal length of the light reflected by the circular mirror 1 is short, that is, if the direction in which the optical Power (Power) is strong is matched with the X axis, the focal length of the light reflected is long because the light becomes convex in the X axis, and the focal length of the light reflected is short because the light becomes concave in the Y axis. Therefore, the difference between the optical power of the light in the X-axis direction and the optical power of the light in the Y-axis direction is reduced. That is, by adjusting the degree of deformation of the saddle shape, the optical power in the X-axis direction and the optical power in the Y-axis direction are made equal, and astigmatism can be corrected. Here, the degree of deformation of the circular mirror 1 may be set to 0.1 μm or more and 10 μm or less with respect to the circular mirror 1 having a diameter of 10mm or more and 100mm or less, but the degree of deformation of the circular mirror 1 is not limited thereto.

Fig. 2 is an assembly diagram for explaining the structure of the shape variable mirror according to embodiment 1 of the present invention. The shape variable mirror 10 shown in fig. 2 has: a circular reflector 1; and a deformation force generating mechanism 3 including a distance changing part 2, a Y-axis member 4, an X-axis member 5, and a holding member 6.

The distance changing unit 2 includes a piezoelectric actuator link member 2b as a fixed portion fixed to the X-axis back plate 5a, a 1 st piezoelectric actuator 2a that is in contact with the Y-axis back plate 4a and is capable of expanding and contracting between the piezoelectric actuator link member 2b and the Y-axis back plate 4a, and a 2 nd piezoelectric actuator 2c that is in contact with the holding member 6 and is capable of expanding and contracting between the piezoelectric actuator link member 2b and the holding member 6. The 1 st piezoelectric actuator 2a and the 2 nd piezoelectric actuator 2c are actuators capable of accurately controlling the length by applying a voltage by the inverse piezoelectric effect. The piezoelectric actuator connecting member 2b connects the 1 st piezoelectric actuator 2a and the 2 nd piezoelectric actuator 2 c. According to the distance changing unit 2, at the X-axis intersection point Pxf1 shown in fig. 1, a load Ff1 in the-Z direction, which is a direction in which the circular mirror 1 is pulled, can be generated, at the X-axis intersection point Pxf2, a load Ff2 in the-Z direction, which is a direction in which the circular mirror 1 is pulled, at the Yb-axis intersection point Pyb1 shown in fig. 1, a load Fb1 in the + Z direction, which is a direction in which the circular mirror 1 is pressed, can be generated, and at the Yb-axis intersection point Pyb2, a load Fb2 in the + Z direction, which is a direction in which the circular mirror 1 is pressed, can be generated. By using the distance changing unit 2, the distance between the X-axis member 5 and the circular mirror 1 and the distance between the Y-axis member 4 and the circular mirror 1 can be changed symmetrically to the circular mirror 1. Further, the distance between the X-axis member 5 and the circular mirror 1 and the distance between the Y-axis member 4 and the circular mirror 1 can be changed by the same amount symmetrically to the circular mirror 1.

The deforming force generating mechanism 3 is disposed on the rear surface side of the circular mirror 1, and generates a force for deforming the mirror surface 1sf in a saddle shape. The circular mirror 1 can be deformed into a saddle shape by the deforming force generating mechanism 3 having a simple structure. The deformation force generation mechanism 3 includes: a Y-axis member 4 as the 1 st member fixed to the rear surface 1sb of the circular mirror 1 at 2 positions corresponding to Yb-axis intersections Pyb1, Pyb2 shown in fig. 1; an X-axis member 5 which is the 2 nd member fixed to the back surface 1sb of the circular mirror 1 at 2 positions corresponding to the X-axis intersections Pxf1, Pxf2 and arranged so as to straddle the Y-axis member 4; and a distance changing unit 2. The 1 st piezoelectric actuator 2a of the distance changing section 2 changes the distance between the Y-axis member 4 and the X-axis member 5. The 2 nd piezoelectric actuator 2c of the distance changing section 2 changes the distance between the X-axis member 5 and the holding member 6. A line segment parallel to the X axis and a line segment parallel to the Y axis and connecting the portions to which the Y axis member 4 is fixed intersect each other on the back surface 1 sb.

The Y-shaft member 4 as the 1 st member includes: a Y-axis back plate 4a which is circular with the same diameter as the circular mirror 1 and has a thickness; and Y-axis legs 4b1 and 4b2, which are 2 rectangular legs formed perpendicularly on the Y-axis back plate 4a on the surface of the Y-axis back plate 4a on the circular mirror 1 side. The Y-axis back plate 4a is a 1 st plate portion opposed to the back surface 1sb of the circular mirror 1. The Y-axis legs 4b1 and 4b2 are the 1 st leg portions extending in the + Z direction from the Y-axis back plate 4a and coming into contact with the rear surface 1sb of the circular mirror 1. Since the length of the Y-axis leg 4b1 is equal to the length of the Y-axis leg 4b2, the Y-axis back plate 4a is disposed parallel to the circular mirror 1 in a state of being fixed to the circular mirror 1. The Y-axis legs 4b1 and 4b2 have a square shape in a cross section perpendicular to the longitudinal direction, and have the same cross-sectional shape in the longitudinal direction. The Y-axis leg bottom surfaces 4c1 and 4c2 are bottom surfaces of the Y-axis legs 4b1 and 4b 2. The Y-axis legs 4b1 and 4b2 are disposed at the end of the Y-axis back plate 4a, and a line segment connecting the center of the Y-axis leg bottom surface 4c1 of the Y-axis leg 4b1 and the center of the Y-axis leg bottom surface 4c2 of the Y-axis leg 4b2 passes through the center of the Y-axis back plate 4 a. Here, a straight line connecting the center of the Y-axis foot bottom surface 4c1 and the center of the Y-axis foot bottom surface 4c2 becomes the Y-axis. The Y axis passes through the center of the Y-axis back plate 4a and is orthogonal to the X axis. At the intersection of the X axis and the outer circumference circle in the Y axis back plate 4a, notches 4d1, 4d2 are provided for the X axis member 5 to pass through. However, the shape of the Y-axis legs 4b1 and 4b2 in the cross section perpendicular to the longitudinal direction is not limited to a square shape, and may be a circular shape.

The Y-axis back plate 4a and the Y-axis legs 4b1 and 4b2 may be integrally molded or may be formed by joining members formed independently of each other. The Y-axis member 4 and the circular reflecting mirror 1 can be formed by cutting the same object to be processed. The circular reflecting mirror 1 and the X-axis member 5 can be formed by cutting the same object. The circular mirror 1, the X-axis member 5, and the Y-axis member 4 may be formed by cutting the same object.

The Y-axis leg bottom surface 4c1 has a square shape in a plane perpendicular to the Y-axis leg 4b1, and the Y-axis leg bottom surface 4c2 has a square shape in a plane perpendicular to the Y-axis leg 4b 2. The 2Y-axis foot bottom surfaces 4c1 and 4c2 are fixed to the back surface 1sb of the circular reflecting mirror 1 by a fixing method such as screw fastening, brazing, or adhesion by an adhesive so that the fixing surfaces are not peeled off by a tensile force. In addition, in the fixing at the portion other than the portion where the Y-axis foot bottom surfaces 4c1, 4c2 are fixed to the back surface 1sb in the shape variable mirror 10, the same method as that for the fixing at the back surface 1sb and the Y-axis foot bottom surfaces 4c1, 4c2 is also used.

The X-axis member 5 as the 2 nd member has the same shape as the Y-axis member 4, and includes: an X-axis back plate 5a which is circular with the same diameter as the circular mirror 1 and has a thickness; and X-axis legs 5b1 and 5b2, which are rectangular legs formed perpendicularly on the X-axis back plate 5a on the surface of the X-axis back plate 5a on the circular mirror 1 side. The X-axis back plate 5a is a 2 nd plate portion opposed to the Y-axis back plate 4 a. The X-axis legs 5b1 and 5b2 are the 2 nd leg portions extending from the X-axis back plate 5a across the Y-axis member 4 and coming into contact with the back surface 1sb of the circular mirror 1. The X-axis leg bottom surfaces 5c1, 5c2 of the X-axis member 5 are fixed to the back surface 1sb of the circular mirror 1. The points at which the shape of the X-axis member 5 and the shape of the Y-axis member 4 are different are the following 3 points: the X-axis legs 5b1 and 5b2 are longer than the Y-axis legs 4b1 and 4b2, and have no notch in the X-axis back plate 5a and a through hole 5f in the center of the X-axis back plate 5 a. In the back surface 1sb of the circular reflecting mirror 1, a line segment connecting portions where the 2Y-axis legs 4b1 and 4b2 abut each other intersects with a line segment connecting portions where the 2X-axis legs 5b1 and 5b2 abut each other.

The diameter of the through hole 5f is larger than the diameter of the 2 nd piezoelectric actuator 2c and smaller than or equal to the diameter of the piezoelectric actuator connecting member 2 b. Here, the X-axis back plate 5a and the piezoelectric actuator connecting member 2b are fixed by a fixing method such as screw fastening, brazing, or adhesion with an adhesive material between the side surface of the piezoelectric actuator connecting member 2b and the side surface of the through hole 5f so that the fixing surface is not peeled off by tensile force. Alternatively, the surface of the piezoelectric actuator connecting member 2b on the X-axis member 5 side and the surface of the X-axis back plate 5a on the circular mirror 1 side may be fixed by a fixing method such as screw fastening, soldering, or adhesion by an adhesive material so that the fixing surfaces do not peel off due to tensile force. In addition, the 2 nd piezoelectric actuator 2c is disposed so as to penetrate the through hole 5f by any fixing method.

The distance changing unit 2 fixes the 1 st piezoelectric actuator 2a to the circular mirror 1 side and fixes the 2 nd piezoelectric actuator 2c to the holding member 6 side, with respect to the piezoelectric actuator connecting member 2b having a smaller diameter than the circular mirror 1.

The X-axis member 5 and the piezoelectric actuator connecting member 2b may be formed by cutting the same object to be processed.

The surface of the 1 st piezoelectric actuator 2a on the side of the circular mirror 1 is fixed to the center of the Y-axis back plate 4a on the side opposite to the circular mirror 1. The surface of the 2 nd piezoelectric actuator 2c on the holding member 6 side is fixed to the holding member center 6e of the holding member 6 on the circular mirror 1 side.

The holding member 6 is circular with the same diameter as the circular mirror 1, and the holding member center 6e is fixed to the surface of the 2 nd piezoelectric actuator 2c on the holding member 6 side. The holding member 6 holds the Y-axis member 4 and the X-axis member 5 via the distance changing section 2.

Next, deformation of the mirror surface 1sf of the circular mirror 1 in a saddle shape will be described. Here, the reference plane is defined in the following manner. The reference surface is a surface of the holding member 6 on the circular mirror 1 side. One end of the 2 nd piezoelectric actuator 2c of the distance changing unit 2 is fixed to the center of the reference plane. The other end of the 2 nd piezoelectric actuator 2c is fixed to the piezoelectric actuator link member 2b, and the piezoelectric actuator link member 2b is fixed to the center of the X-axis member 5. The surface of the X-axis back plate 5a on the circular mirror 1 side is the 2 nd surface. One end of the 1 st piezoelectric actuator 2a is fixed to the surface of the piezoelectric actuator connecting member 2b opposite to the surface to which the 2 nd piezoelectric actuator 2c is fixed, and the other end of the 1 st piezoelectric actuator 2a is fixed to the center of the surface of the Y-axis back plate 4a opposite to the circular mirror 1. The surface of the Y-axis back plate 4a opposite to the circular mirror 1 is the 3 rd surface. The rear surface 1sb of the circular mirror 1 to which the X-axis legs 5b1 and 5b2 and the Y-axis legs 4b1 and 4b2 are fixed is the 4 th surface. The center of the Y-axis back plate 4a and the center of the X-axis back plate 5a pass through the center of the circular mirror 1 and exist on a straight line perpendicular to the circular mirror 1. Therefore, the 1 st piezoelectric actuator 2a and the 2 nd piezoelectric actuator 2c are also present on the straight line. That is, the 1 st piezoelectric actuator 2a and the 2 nd piezoelectric actuator 2c change the distance between both ends thereof on a straight line perpendicular to the circular mirror 1. The length difference between the Y-axis legs 4b1, 4b2 and the X-axis legs 5b1, 5b2 is set so that the length of the 1 st piezoelectric actuator 2a is the same as that in the middle of its variable range. When a voltage is applied to the 1 st piezoelectric actuator 2a, the Y-axis leg bottom surfaces 4c1 and 4c2 and the X-axis leg bottom surfaces 5c1 and 5c2 are fixed to the rear surface 1sb of the circular mirror 1 in a state where the length of the 1 st piezoelectric actuator 2a is different from the lengths of the Y-axis legs 4b1 and 4b2 and the X-axis legs 5b1 and 5b 2.

Next, a method of controlling the 1 st piezoelectric actuator 2a and the 2 nd piezoelectric actuator 2c will be described. Fig. 3 is a conceptual diagram 1 for explaining a change in shape of the shape variable mirror 10 shown in fig. 2. As shown in fig. 3, if a voltage is applied to the 2 nd piezoelectric actuator 2c, the 2 nd surface moves in the + Z direction with respect to the reference surface. If the 2 nd surface moves in the + Z direction, the 3 rd surface and the 4 th surface move similarly to the above, and only the mirror surface 1sf of the circular mirror 1 moves in the + Z direction with respect to the reference surface.

Fig. 4 is a conceptual diagram 2 for explaining a change in the shape of the variable shape mirror 10 shown in fig. 2. As shown in fig. 4, if the 1 st piezoelectric actuator 2a is lengthened, the 2 nd surface does not change from the reference surface, and the 3 rd surface moves in the + Z direction. At this time, in the rear surface 1sb of the circular mirror 1 which is the 4 th surface, the X-axis intersection points Pxf1 and Pxf2 of the X-axis leg bottom surfaces 5c1 and 5c2 to which the X-axis member 5 is fixed do not move in the + Z direction, and the Yb-axis intersection points Pyb1 and Pyb2 of the Y-axis leg bottom surfaces 4c1 and 4c2 to which the Y-axis member 4 is fixed move in the + Z direction.

Fig. 5 is a conceptual diagram for explaining a change in the shape of the circular mirror 1 included in the variable-shape mirror 10 shown in fig. 2. By performing the shape change as described above, the mirror surface 1sf of the circular mirror 1 is deformed into a saddle shape as shown in fig. 5. However, the mirror surface center 1e also changes in the + Z direction with respect to the reference plane.

Fig. 6 is a conceptual diagram 3 for explaining a change in the shape of the variable shape mirror 10 shown in fig. 2. As shown in fig. 6, a voltage is applied to the 2 nd piezoelectric actuator 2c to lengthen the 2 nd piezoelectric actuator 2c, and accordingly, the 1 st piezoelectric actuator 2a is shortened by 2 times in a direction opposite to the direction in which the 2 nd piezoelectric actuator 2c is lengthened. Then, the 2 nd surface changes in the + Z direction with respect to the reference surface, and the 3 rd surface changes in the-Z direction with respect to the reference surface. The amount of change in the-Z direction from the reference plane of the 3 rd plane is the same as the amount of change in the + Z direction from the reference plane of the 2 nd plane. Thus, the distance changing unit 2 moves the Y-axis backing plate 4a in the-Z direction and moves the X-axis backing plate 5a in the + Z direction, thereby moving the Y-axis backing plate 4a and the X-axis backing plate 5a in opposite directions to each other in the Z-axis direction. The distance changing unit 2 moves the Y-axis back plate 4a and the X-axis back plate 5a in the Z-axis direction in opposite directions to each other, and changes the distance between the Y-axis back plate 4a and the circular mirror 1 symmetrically with the distance between the X-axis back plate 5a and the circular mirror 1. Here, when changing such that one of the 2 distances is longer and the other is shorter, the 2 distances are symmetrically changed. The distance changing unit 2 changes the distance between the Y-axis back plate 4a and the circular mirror 1 by the same amount symmetrically to the distance between the X-axis back plate 5a and the circular mirror 1. Here, when the distance for increasing one of the 2 distances is the same as the distance for decreasing the other of the 2 distances, the 2 distances are symmetrically changed by the same amount. The Y-axis legs 4b1, 4b2 move in the-Z direction in association with the movement of the Y-axis back plate 4a in the-Z direction. The X-axis legs 5b1, 5b2 move in the + Z direction in association with the movement of the X-axis back plate 5a in the + Z direction. In the rear surface 1sb of the circular mirror 1 as the 4 th surface, the X-axis intersection Pxf1 of the X-axis leg bottom surface 5c1 to which the X-axis member 5 is fixed and the X-axis intersection Pxf2 of the X-axis leg bottom surface 5c2 to which the X-axis member 5 is fixed change in the + Z direction, and the Yb-axis intersection Pyb1 of the Y-axis leg bottom surface 4c1 to which the Y-axis member 4 is fixed and the Yb-axis intersection Pyb2 of the Y-axis leg bottom surface 4c2 to which the Y-axis member 4 is fixed change in the-Z direction by the same amount as the amount of change in the X-axis intersections Pxf1, Pxf 2.

Fig. 7 is a conceptual diagram for explaining a change in the shape of the circular mirror 1 included in the variable-shape mirror 10 shown in fig. 2. By performing the shape change as described above, the mirror surface 1sf of the circular mirror 1 is deformed into a saddle shape as shown in fig. 7. The distance in the Z direction from the reference plane of the mirror surface center 1e does not change. Here, the length of the 1 st piezoelectric actuator 2a is set to 2 times in the opposite direction to the change in length of the 2 nd piezoelectric actuator 2c, but if the length is changed in the opposite direction, the change in the Z direction of the mirror surface center 1e of the circular mirror 1 with respect to the reference surface becomes smaller than the case where the length is not changed. Therefore, even if the mirror surface 1sf of the circular mirror 1 is deformed in a saddle shape, the change in the Z direction of the mirror surface center 1e of the circular mirror 1 with respect to the reference surface of the holding member 6 can be suppressed.

The rigidity of the circular mirror 1, the Y-axis member 4, the X-axis member 5, and the holding member 6 is adjusted to such an extent that the shape can be changed. As an example, if the rigidity of the Y-axis member 4, the X-axis member 5, and the holding member 6 is smaller than the rigidity of the circular mirror 1, the ratio of the deformation of the circular mirror 1 to the change in distance by the distance changing section 2 is small, and the fine deformation control of the circular mirror 1 can be realized.

Next, description will be given by taking an example of a case where astigmatism of a laser beam of the laser processing apparatus is corrected by the shape variable mirror 10. The configuration of the laser processing apparatus is described in detail later, but the shape variable mirror 10 is provided in the middle of the propagation path from the laser oscillator to the processing point. Even when applied to a device other than a laser processing device, the same operation is used to correct the astigmatism, and the mirror reflection position does not change, so that the optical axis does not shift. The laser beam shape becomes elliptical in the presence of astigmatism. The cylindrical shape-variable mirror 10 itself is rotated in a barrel holder fixed to the holding member 6, and the direction in which the diameter of the laser beam shape is longer or shorter is made to coincide with the X axis or Y axis of the shape-variable mirror 10.

When the 1 st piezoelectric actuator 2a and the 2 nd piezoelectric actuator 2c are initial values, first, the 2 nd piezoelectric actuator 2c is lengthened, and the 1 st piezoelectric actuator 2a is shortened by 2 times the amount of change of the 2 nd piezoelectric actuator 2 c. At this time, if the laser beam shape is close to a perfect circle from an ellipse, the 2 nd piezoelectric actuator 2c is lengthened in this state, and the 1 st piezoelectric actuator 2a is continuously shortened by 2 times the amount of change of the 2 nd piezoelectric actuator 2c, and is adjusted so that the laser beam shape is close to a perfect circle. Conversely, when the 2 nd piezoelectric actuator 2c is lengthened and the 1 st piezoelectric actuator 2a is shortened by 2 times the amount by which the 2 nd piezoelectric actuator 2c is lengthened, if the degree of flattening is increased, the 2 nd piezoelectric actuator 2c is lengthened and the 1 st piezoelectric actuator 2a is shortened by 2 times the amount by which the 2 nd piezoelectric actuator 2c is changed after the shape variable mirror 10 itself in the lens barrel holder is rotated by 90 degrees around the axial center. As described above, while monitoring the laser beam shape, the lengths of the 1 st piezoelectric actuator 2a and the 2 nd piezoelectric actuator 2c are changed and adjusted so that the laser beam shape approaches a perfect circle.

Here, the cross-sectional shape in the axial direction of the shape-variable mirror 10 is a circle, but the present invention is not limited to this, and may be other than a circle. However, when the shape is circular, the degree of flatness becomes large or small as described above, and the shape-variable mirror 10 itself can be rotated around the axial center. In addition, the reflector is preferably circular if isotropy is considered, but the present invention is not limited thereto, and may be elliptical or polygonal.

In the above description, the X axis and the Y axis, which are 2 axes for determining the position of the load, are orthogonal to each other in order to deform the circular mirror 1. When the 2 axes that determine the position of the load are not orthogonal, if the positions of the axes, that is, the angles are made different, the angle between the portion deformed to be the maximum concave and the portion deformed to be the maximum convex becomes 90 degrees. Therefore, by setting the straight line passing through the portion deformed to be the most concave as the Y axis and the straight line passing through the portion deformed to be the most convex as the X axis, and by making either the X axis or the Y axis coincide with the direction in which the length of the shape of the light is long or short, the astigmatism can be corrected by deforming the circular mirror 1.

Embodiment 2.

While embodiment 1 has been described as a mode in which the circular mirror 1 is deformed by the distance changing section having the piezoelectric actuator, the present invention is not limited to this, and the circular mirror 1 may be deformed by adjusting the screw instead of the piezoelectric actuator as described in embodiment 2. Note that, with respect to portions not specifically described in embodiment 2, the description of embodiment 1 is cited.

Fig. 8 is an assembly diagram for explaining the structure of the shape variable mirror according to embodiment 2 of the present invention. In fig. 8, the same components as those in fig. 2 are denoted by the same reference numerals. The shape variable mirror 10a shown in fig. 8 includes a circular mirror 1 and a deforming force generating mechanism portion 3A. The deformation force generation mechanism 3A generates a force that deforms the mirror surface 1sf in a saddle shape. The deformation force generation mechanism portion 3A includes: the Y-axis member 4A, X includes an axis member 5A, a holding member 6A, an adjusting screw 7 as a distance changing portion, and rotation stopping members 8 and 8A. The adjustment screw 7 has a 1 st screw 7a, a 2 nd screw 7b, and a 3 rd screw 7 c. The 1 st screw 7a, the 2 nd screw 7b and the 3 rd screw 7c are different in pitch from each other. In the structure of fig. 8, a different structure corresponding to the structure of fig. 2 is denoted by a reference numeral "a". That is, the Y-axis member 4A in fig. 8 corresponds to the Y-axis member 4 in fig. 2.

The Y-axis member 4A has a Y-axis back plate 4Aa and Y-axis legs 4Ab1, 4Ab 2. The Y-axis back plate 4Aa is a 1 st plate portion facing the back surface 1sb of the circular mirror 1. The Y-axis legs 4Ab1 and 4Ab2 are 1 st leg portions extending in the + Z direction from the Y-axis back plate 4Aa and coming into contact with the rear surface 1sb of the circular mirror 1. The Y-axis member 4A is different from the Y-axis member 4 shown in fig. 2 in that it has a Y-axis screw hole 4Af at the center, and is otherwise the same as the Y-axis member 4. The Y-axis leg bottom surfaces 4Ac1 and 4Ac2 are bottom surfaces of the Y-axis legs 4Ab1 and 4Ab 2. Further, the Y-axis member 4A is provided with notches 4Ad1, 4Ad 2. The Y-axis member positioning holes 4Ag1 and 4Ag2 are provided on the Y-axis back plate 4Aa radially outward of the Y-axis screw hole 4Af and radially inward of the notches 4Ad1 and 4Ad 2. The columnar portions 8c and 8Ac of the rotation stop members 8 and 8A are inserted into the Y-axis member positioning holes 4Ag1 and 4Ag2, respectively.

The X-axis member 5A has an X-axis back plate 5Aa and X-axis legs 5Ab1, 5Ab 2. The X-axis back plate 5Aa is a 2 nd plate portion opposed to the Y-axis back plate 4 Aa. The X-axis legs 5Ab1 and 5Ab2 are the 2 nd leg portions extending from the X-axis back plate 5Aa across the Y-axis member 4A and coming into contact with the rear surface 1sb of the circular mirror 1. The X-axis member 5A is different from the X-axis member 5 shown in fig. 2 in that it has an X-axis screw hole 5Af in place of the through hole 5f at the center, 2 positioning holes 5Ag1 and 5Ag2 are provided on the outer side in the radial direction than the X-axis screw hole 5Af and on the inner side than the X-axis legs 5Ab1 and 5Ab2, and the rest are the same as the X-axis member 5. Further, the X-axis leg bottom surfaces 5Ac1, 5Ac2 are bottom surfaces of the X-axis legs 5Ab1, 5Ab 2.

The holding member 6A is different from the holding member 6 shown in fig. 2 in that it has a holding member screw hole 6Af with a different pitch of threads at the center, a holding member positioning hole 6Ag1 corresponding to the positioning hole 5Ag1 of the X-axis member 5A, and a holding member positioning hole 6Ag2 corresponding to the positioning hole 5Ag 2. The holding member 6A holds the Y-axis member 4A and the X-axis member 5A via the adjustment screw 7.

The adjusting screw 7 includes a 1 st screw 7a screwed into the Y-axis back plate 4Aa, a 2 nd screw 7b screwed into the X-axis back plate 5Aa, and a 3 rd screw 7c screwed into the holding member 6A. The 1 st screw 7a corresponds to the Y-axis screw hole 4 Af. The 2 nd screw 7b corresponds to the X-axis screw hole 5 Af. The 3 rd screw 7c corresponds to the holding member screw hole 6 Af. The 1 st screw 7a, the 2 nd screw 7b, and the 3 rd screw 7c are formed with external threads having different thread pitches. Although not shown, a hole for twisting for applying a rotational force is formed in the end portion on the 3 rd screw 7c side. The hole for twisting can be exemplified by a hexagonal hole. The adjusting screws 7 change the distance between the Y-axis back plate 4Aa and the circular mirror 1 symmetrically to the distance between the X-axis back plate 5Aa and the circular mirror 1. The adjustment screws 7 change the distance between the Y-axis back plate 4Aa and the circular mirror 1 by the same amount symmetrically to the distance between the X-axis back plate 5Aa and the circular mirror 1.

The rotation stopper 8 has a cylindrical portion 8c and a head portion 8d provided at one end side of the cylindrical portion 8 c. The rotation stopper 8A has a cylindrical portion 8Ac and a head portion 8Ad provided on one end side of the cylindrical portion 8 Ac. The outer diameter of the columnar portion 8c is smaller than the diameter of the Y-axis member positioning hole 4Ag1, the diameter of the positioning hole 5Ag1, and the diameter of the holding member positioning hole 6Ag1, and the columnar portion 8c is insertable into the positioning hole 5Ag1 and the Y-axis member positioning hole 4Ag1 of the X-axis member 5A through the holding member positioning hole 6Ag1, and is insertable into and removable from the Y-axis member positioning hole 4Ag1, the positioning hole 5Ag1, and the holding member positioning hole 6Ag 1. The outer diameter of the columnar portion 8Ac is smaller than the diameter of the Y-axis member positioning hole 4Ag2, the diameter of the positioning hole 5Ag2, and the diameter of the holding member positioning hole 6Ag2, and the columnar portion 8Ac is insertable into the positioning hole 5Ag2 and the Y-axis member positioning hole 4Ag2 of the X-axis member 5A through the holding member positioning hole 6Ag2, and is insertable into and removable from the Y-axis member positioning hole 4Ag2, the positioning hole 5Ag2, and the holding member positioning hole 6Ag 2. The head portion 8d is provided to have an outer diameter larger than the holding member positioning hole 6Ag1, and if it is in contact with the holding member 6A, the rotation stopping member 8 is stopped. The head 8Ad is formed to have an outer diameter larger than the holding member positioning hole 6Ag2, and if it is in contact with the holding member 6A, the rotation stop member 8A stops.

In addition, although two rotation preventing members are shown in fig. 8, the present invention is not limited to this, and the number of rotation preventing members may be any number as long as the rotation direction of the shaft member 5A and the holding member 6A of the Y-shaft member 4A, X can be restricted.

Next, the saddle-shaped deformation of the mirror surface 1sf of the circular mirror 1 will be described. Here, the reference plane is defined as follows. The reference surface is a surface of the holding member 6A on the circular mirror 1 side. The center of the 3 rd screw 7c of the adjusting screw 7 is arranged at the center of the reference plane. The center of the 3 rd screw 7c and the center of the 2 nd screw 7b are coaxial, and the center of the 2 nd screw 7b is disposed at the center of the X-axis back plate 5 Aa. The surface of the X-axis back plate 5Aa on the circular mirror 1 side is the 2 nd surface. The centers of the 2 nd screw 7b and the 1 st screw 7a are coaxial, and the center of the 1 st screw 7a is disposed at the center of the Y-axis back plate 4 Aa. The center of the Y-axis back plate 4Aa and the mirror surface center 1e of the circular mirror 1 are coaxially arranged. The surface of the Y-axis back plate 4Aa opposite to the circular mirror 1 is the 3 rd surface. The rear surface 1sb of the circular mirror 1 to which the X-axis legs 5Ab1 and 5Ab2 and the Y-axis legs 4Ab1 and 4Ab2 are fixed is the 4 th surface.

The center of the Y-axis back plate 4Aa and the center of the X-axis back plate 5Aa both pass through the center of the circular mirror 1 and exist on a straight line perpendicular to the circular mirror 1. Therefore, the 1 st screw 7a, the 2 nd screw 7b, and the 3 rd screw 7c exist on a straight line. That is, the 1 st screw 7a, the 2 nd screw 7b, and the 3 rd screw 7c have their distances varied on a straight line perpendicular to the circular reflecting mirror 1. The length difference between the Y-axis leg 4Ab1 and the X-axis leg 5Ab1 is set to be the same as the length when the center portion in the longitudinal direction of the 1 st screw 7a is at the same position as the center portion in the thickness direction of the Y-axis back plate 4Aa, and the center portion in the longitudinal direction of the 2 nd screw 7b is at the same position as the center portion in the thickness direction of the X-axis back plate 5 Aa. The length difference between the Y-axis leg 4Ab2 and the X-axis leg 5Ab2 is set to be the same as the length when the center portion in the longitudinal direction of the 1 st screw 7a is at the same position as the center portion in the thickness direction of the Y-axis back plate 4Aa, and the center portion in the longitudinal direction of the 2 nd screw 7b is at the same position as the center portion in the thickness direction of the X-axis back plate 5 Aa.

Next, the pitch of the 1 st screw 7a, the 2 nd screw 7b, and the 3 rd screw 7c will be described. Here, the pitch width Pa is set for the 1 st screw 7a, the pitch width Pb is set for the 2 nd screw 7b, and the pitch width Pc is set for the 3 rd screw 7 c. In embodiment 2, the difference Pc-Pb obtained by subtracting the pitch width Pb of the 2 nd screw 7b from the pitch width Pc of the 3 rd screw 7c is opposite in sign to the difference Pc-Pa obtained by subtracting the pitch width Pa of the 1 st screw 7a from the pitch width Pc of the 3 rd screw 7 c. In the case where the pitch width Pb is smaller than the pitch width Pc, the pitch width Pa is set larger than the pitch width Pc. The absolute value of Pc-Pb, which is the difference between the pitch width Pc and the pitch width Pb, is equal to the absolute value of Pc-Pa, which is the difference between the pitch width Pc and the pitch width Pa.

Next, the deformation of the circular reflecting mirror 1 when the adjustment screw 7 is rotated will be described. First, if the adjustment screw 7 is rotated 1 rotation in the screwing direction, the adjustment screw 7 changes in the + Z direction by the pitch width Pc of the 3 rd screw 7c with respect to the reference surface. At this time, the X-axis member 5A is changed in the-Z direction by the pitch width Pb of the 2 nd screw 7 b. That is, when the pitch width Pc of the 3 rd screw 7c is larger than the pitch width Pb of the 2 nd screw 7b, the X-axis member 5A changes in the + Z direction by the amount Pc — Pb with respect to the screw reference plane. The Y-axis member 4A changes in the-Z direction by the pitch width Pa of the 1 st screw 7 a. That is, when the pitch width Pc of the 3 rd screw 7c is smaller than the pitch width Pa of the 1 st screw 7a, the Y-axis member 4A changes in the-Z direction by Pc-Pa with respect to the screw reference surface. At this time, the mirror surface 1sf of the circular mirror 1 is deformed in a saddle shape. Further, the mirror surface center 1e of the mirror surface 1sf is suppressed from changing in the Z direction with respect to the reference surface. As a result, the variable-shape mirror 10a can be obtained in which the mirror surface 1sf of the circular mirror 1 is deformed in a saddle shape, and the change in the Z direction of the mirror surface center 1e in the mirror surface 1sf of the circular mirror 1 is suppressed with respect to the reference surface of the holding member 6A. The screw reference surface is not limited to a specific surface as long as it is a surface of the screw in the horizontal direction, and the screw reference surface may be a plane of a stepped portion which is a boundary between the 2 nd screw 7b and the 3 rd screw 7 c.

As described above, when the pitch width Pb is smaller than the pitch width Pc and the pitch width Pa is larger than the pitch width Pc, the adjustment screw 7 is rotated in the direction of being screwed in the + Z direction when the mirror surface 1sf is deformed. In the pitch widths Pa, Pb, and Pc, a pitch width Pb larger than the pitch width Pc and a pitch width Pa smaller than the pitch width Pc may be set. When the pitch width Pb is larger than the pitch width Pc and the pitch width Pa is smaller than the pitch width Pc, the adjustment screw 7 is rotated in a direction to be screwed out in the-Z direction when the mirror surface 1sf is deformed.

Next, a description will be given by taking an example of a case where astigmatism of a laser beam of the laser processing apparatus is corrected by the shape variable mirror 10a, as in embodiment 1. The configuration of the laser processing apparatus is described in detail later, but a shape variable mirror 10a is provided in the middle of the propagation path from the laser oscillator to the processing point. The cylindrical shape-variable mirror 10a itself is rotated in a barrel holder fixed to the holding member 6A, and the direction in which the diameter of the laser beam shape is longer or shorter is made to coincide with the X axis or Y axis of the shape-variable mirror 10 a.

First, the adjustment screw 7 is rotated in the screwing direction. At this time, if the laser beam shape is close to a perfect circle from an ellipse, the adjustment screw 7 is rotated in the screwing direction in this state, and the laser beam shape is adjusted to be close to a perfect circle. Conversely, if the adjusting screw 7 is rotated in the screwing direction and the degree of flattening is increased, the shape-variable mirror 10a itself in the barrel holder is rotated by 90 degrees about the axial center, and then the adjusting screw 7 is rotated in the screwing direction. As described above, the laser beam shape is adjusted to a length close to a perfect circle while monitoring the laser beam shape.

Here, the cross-sectional shape in the axial direction of the shape-variable mirror 10a is circular, but the present invention is not limited to this, and may be other than circular. However, when the shape is circular, the shape-variable mirror 10a itself can be rotated around the axis center depending on whether the degree of flatness is large or small as described above. In addition, the reflector is preferably circular if isotropy is taken into consideration, but the present invention is not limited thereto, and may be elliptical or polygonal.

In the above description, the X axis and the Y axis, which are 2 axes for determining the position of the load, are made orthogonal to each other in order to deform the circular mirror 1. When the 2 axes that determine the position of the load are not orthogonal, if the positions of the axes, that is, the angles are made different, the angle between the portion deformed to be the maximum concavity and the portion deformed to be the maximum convexity becomes 90 degrees. Therefore, the astigmatism can be corrected by deforming the circular mirror 1 by setting a line passing through the portion deformed to be the maximum concavity as the Y axis and a line passing through the portion deformed to be the maximum convexity as the X axis, and by making either the X axis or the Y axis coincide with the direction in which the length of the shape of the light is long or short.

Embodiment 3.

In the present embodiment, a mode in which a lock mechanism for locking the adjustment screw 7 is added to the variable geometry mirror 10a of embodiment 2 described above will be described. Fig. 9 is an assembly diagram for explaining the structure of the shape variable mirror according to embodiment 3 of the present invention. The shape-variable mirror 10b shown in fig. 9 is different from the shape-variable mirror 10a in that it includes a lock member 9. In fig. 9, the same components as those in fig. 2 and 8 are denoted by the same reference numerals.

The shape variable mirror 10B shown in fig. 9 includes a circular mirror 1 and a deforming force generating mechanism portion 3B. The deformation force generation mechanism 3B generates a force to deform the mirror surface 1sf in a saddle shape. The deformation force generation mechanism 3B is configured by adding a lock member 9 to the structure of the deformation force generation mechanism 3A according to embodiment 2. The locking member 9 is a hexagonal locking nut having a smaller outer diameter than the holding member 6A, a thickness, and a female screw corresponding to the 3 rd screw 7c at the center. The locking member 9 is not limited to a hexagonal locking nut, and may be circular.

In fig. 9, the 3 rd screw 7c protrudes from the surface of the holding member 6A opposite to the surface facing the circular mirror 1 in the assumed rotation range, and has a length that can be fastened to the locking member 9.

As described in embodiment 3, even when the mirror surface 1sf of the circular mirror 1 is deformed in a saddle shape, the variable-shape mirror 10b suppresses the change in the Z direction of the mirror surface center 1e of the circular mirror 1 with respect to the reference surface of the holding member 6A, and the amount of deformation of the circular mirror 1 can be stably maintained by the locking member 9 that locks the rotation of the adjustment screw 7.

In embodiments 1 to 3, the shape variable mirrors 10, 10a, 10b include the Y- axis members 4, 4A as the 1 st member fixed to the back surface 1sb, and the X-axis members 5, 5A as the 2 nd member fixed to the back surface 1 sb. The Y-axis foot bottom surfaces 4c1, 4Ac1, 4c2, 4Ac2 and the X-axis foot bottom surfaces 5c1, 5Ac1, 5c2, 5Ac2 are fixed to the back surface 1sb by screw fastening, brazing, or an adhesive material so as not to be peeled off from the back surface 1sb by a tensile force. The present invention is not limited to the fixing of the 1 st and 2 nd members to the back surface 1 sb. The 1 st member and the 2 nd member may be contacted without being fixed to the back surface 1 sb. In embodiments 4 to 6 described below, a configuration of a variable shape mirror including the 1 st member and the 2 nd member in contact with the rear surface 1sb will be described. According to embodiments 4 to 6, the shape variable mirror can deform the circular mirror 1 in which the fixing of the 1 st member and the 2 nd member by screw fastening, brazing, or an adhesive material is not possible, as in embodiments 1 to 3. In embodiments 4 to 6, "contact" means that objects are not fixed but abut each other.

Embodiment 4.

In embodiment 4, a description will be given of a configuration in which the circular mirror 1 is deformed by the distance changing unit 2 having a piezoelectric actuator. Fig. 10 is an assembly diagram for explaining the structure of the shape variable mirror according to embodiment 4 of the present invention. In embodiment 4, the same components as those in embodiments 1 to 3 are denoted by the same reference numerals. In embodiment 4, the description overlapping with embodiments 1 to 3 is omitted.

The shape variable mirror 10C shown in fig. 10 includes a circular mirror 1 and a deforming force generating mechanism portion 3C. The deforming force generating mechanism 3C includes the distance changing portion 2, the Y-axis member 4C, X, the axis member 5C, and the holding member 6. The distance changing unit 2 includes: a piezoelectric actuator connecting member 2b which is a fixing portion fixed to the X-axis back plate 5 Ca; a 1 st piezoelectric actuator 2a which can be extended and contracted between the piezoelectric actuator connecting member 2b and the Y-axis back plate 4Ca by being brought into contact with the Y-axis back plate 4 Ca; and a 2 nd piezoelectric actuator 2c that can be extended and contracted between the piezoelectric actuator connecting member 2b and the holding member 6 by being brought into contact with the holding member 6. The distance changing unit 2 changes the distance between the Y-axis back plate 4Ca and the circular mirror 1 symmetrically with respect to the distance between the X-axis back plate 5Ca and the circular mirror 1. The distance changing unit 2 changes the distance between the Y-axis back plate 4Ca and the circular mirror 1 by the same amount as the distance between the X-axis back plate 5Ca and the circular mirror 1 symmetrically.

The deformation force generation mechanism 3C generates a force to deform the mirror surface 1sf in a saddle shape. The Y-axis member 4C as the 1 st member is in contact with the back surface 1sb of the circular mirror 1 at 2 positions corresponding to Yb-axis intersections Pyb1, Pyb2 shown in fig. 1. The 2 nd member, i.e., the X-axis member 5C, contacts the mirror surface 1sf of the circular mirror 1 at 2 positions corresponding to the X-axis intersection points Pxf1, Pxf 2. The X-axis member 5C is disposed across the Y-axis member 4C. A line segment that projects a line segment that connects portions that the X-axis member 5C contacts to each other to a line segment of the back surface 1sb and that is parallel to the Y-axis, and a line segment that connects portions that the Y-axis member 4C contacts to each other and that is parallel to the X-axis intersect each other in the back surface 1 sb. The holding member 6 is formed in a circular shape having a diameter equal to or larger than the diameter of the circular mirror 1.

The Y-shaft member 4C has: a Y-axis back plate 4Ca which is circular with the same diameter as the circular mirror 1 and has a thickness; and Y-axis legs 4Cb1 and 4Cb2 each formed in a rectangular shape on the surface of the Y-axis back plate 4Ca on the side of the circular mirror 1 and standing perpendicular to the surface. The Y-axis back plate 4Ca is a 1 st plate portion facing the rear surface 1sb of the circular mirror 1. The Y-axis legs 4Cb1 and 4Cb2 are 1 st leg portions extending from the Y-axis back plate 4Ca in the + Z direction and coming into contact with the rear surface 1sb of the circular mirror 1. Since the length of the Y-axis leg 4Cb1 is equal to the length of the Y-axis leg 4Cb2 in the Z-axis direction, the Y-axis back plate 4Ca is disposed parallel to the circular mirror 1 in a state where the Y-axis member 4C is in contact with the circular mirror 1. In a cross section of the Y-axis legs 4Cb1 and 4Cb2 perpendicular to the Z-axis direction, which is the longitudinal direction, the Y-axis legs 4Cb1 and 4Cb2 are square. The Y-axis leg bottom surfaces 4Cc1, 4Cc2 are bottom surfaces of the Y-axis legs 4Cb1, 4Cb 2.

The Y-axis legs 4Cb1 and 4Cb2 are disposed at the end of the Y-axis back plate 4 Ca. The Y-axis pins 4Cb1, 4Cb2 are arranged such that a line segment connecting the center of the Y-axis pin bottom surface 4Cc1 and the center of the Y-axis pin bottom surface 4Cc2 passes through the center of the Y-axis back plate 4 Ca. A line segment connecting the center of the Y-axis leg bottom surface 4Cc1 and the center of the Y-axis leg bottom surface 4Cc2 is a line segment parallel to the Y-axis. At intersections of line segments passing through the center of the Y-axis back plate 4Ca and parallel to the X-axis and the outer circumference circle of the Y-axis back plate 4Ca, notches 4Cd1, 4Cd2 for passing the X-axis legs 5Cb1, 5Cb2 are provided. In embodiment 4, the notches 4Cd1 and 4Cd2 may not be provided. The shape of the Y-axis legs 4Cb1 and 4Cb2 in the cross section perpendicular to the longitudinal direction is not limited to a square, and may be a circle. The Y-axis back plate 4Ca and the Y-axis legs 4Cb1 and 4Cb2 may be integrally molded, or may be formed by joining separately formed members.

The X-axis member 5C includes: an X-axis back plate 5Ca which is circular with a larger diameter than the circular mirror 1 and has a thickness; and X-axis legs 5Cb1 and 5Cb2 each formed in a rectangular shape on the surface of the X-axis back plate 5Ca on the side of the circular mirror 1 and standing perpendicular to the surface. The X-axis back plate 5Ca is a 2 nd plate portion facing the Y-axis back plate 4 Ca. The X-axis legs 5Cb1 and 5Cb2 are the 2 nd leg which extends from the X-axis back plate 5Ca across the Y-axis member 4C and abuts against the mirror surface 1sf of the circular mirror 1. The length from the center of the X-axis back plate 5Ca to the X-axis pins 5Cb1 and 5Cb2 is longer than the diameter of the circular mirror 1 and the diameter of the Y-axis back plate 4 Ca. A through-hole 5Cf similar to the through-hole 5f of embodiment 1 is formed in the center of the X-axis back plate 5 Ca.

The lengths of the X-axis legs 5Cb1 and 5Cb2 in the Z-axis direction are longer than the lengths of the Y-axis legs 4Cb1 and 4Cb2 in the Z-axis direction. At the front ends in the + Z direction of the X-axis legs 5Cb1, 5Cb2, there are provided protrusions 5Ch1, 5Ch2 projecting toward the center side of the X-axis back plate 5 Ca. The protrusions 5Ch1 and 5Ch2 are located on the + Z direction side with respect to the circular mirror 1. The boss bottom surfaces 5Cj1, 5Cj2 are surfaces of the bosses 5Ch1, 5Ch2 that face in the-Z direction. The boss bottom surfaces 5Cj1, 5Cj2 are in contact with the mirror surface 1sf of the circular mirror 1. In the rear surface 1sb of the circular mirror 1, a line segment connecting portions where the 2Y-axis legs 4Cb1 and 4Cb2 abut each other intersects with a line segment connecting portions where the 2X-axis legs 5Cb1 and 5Cb2 abut each other. Here, the line segments connecting the portions of the 2X-axis legs 5Cb1 and 5Cb2 abutting against each other include a line segment projecting a line segment connecting the portions of the mirror surface 1sf of the circular mirror 1 abutting against the 2X-axis legs 5Cb1 and 5Cb2 onto the rear surface 1 sb. Further, in fig. 10, the X-axis legs 5Cb1, 5Cb2 show the portion on the X-axis back plate 5Ca side and the portions on the projections 5Ch1, 5Ch2 side separately.

Next, deformation of the mirror surface 1sf of the circular mirror 1 into a saddle shape will be described. In the following description, the reference surface is a surface of the holding member 6 on the circular mirror 1 side. The 2 nd surface is a surface of the X-axis back plate 5Ca on the side of the circular mirror 1. The 3 rd surface is a surface of the Y-axis backing plate 4Ca on the X-axis backing plate 5Ca side. The 4 th surface is a rear surface 1sb of the circular mirror 1.

The center of the Y-axis back plate 4Ca and the center of the X-axis back plate 5Ca both pass through the center of the circular mirror 1 and exist on a straight line perpendicular to the circular mirror 1. The deformation force generation mechanism 3C changes the length of the 1 st piezoelectric actuator 2a on the straight line, thereby changing the interval between the X-axis back plate 5Ca and the Y-axis back plate 4 Ca. The deformation force generation mechanism 3C changes the length of the 2 nd piezoelectric actuator 2C on the straight line, thereby changing the distance between the holding member 6 and the X-axis back plate 5 Ca.

The deformation force generation mechanism 3C is configured such that the difference between the total length of the circular mirror 1, the Y-axis legs 4Cb1, 4Cb2, and the Y-axis back plate 4Ca in the Z-axis direction and the length between the 2 nd surface and the bottom surfaces of the projections 5Cj1, 5Cj2 is the same as the length of the center in the variable length range of the 1 st piezoelectric actuator 2 a. The length of the 1 st piezoelectric actuator 2a is set to a length corresponding to the difference, and thus the Y-axis lead bottom surfaces 4Cc1 and 4Cc2 come into contact with the back surface 1 sb. Further, the boss bottom surfaces 5Cj1, 5Cj2 are in contact with the mirror surface 1 sf.

Next, a method of controlling the 1 st piezoelectric actuator 2a and the 2 nd piezoelectric actuator 2c will be described. Fig. 11 is a conceptual diagram 1 for explaining a change in shape of the shape variable mirror 10c shown in fig. 10. In the shape change shown in fig. 11, a voltage lower than that in the initial state is applied to the 2 nd piezoelectric actuator 2c, thereby making the 2 nd piezoelectric actuator 2c shorter than that in the initial state. Here, the initial state refers to a state in which the length of the 1 st piezoelectric actuator 2a and the 2 nd piezoelectric actuator 2c is the length of the center in the respective variable length ranges. Fig. 11 shows the shape variable mirror 10c in the initial state and the shape variable mirror 10c in which the 2 nd piezoelectric actuator 2c is shorter than in the initial state. The 2 nd piezoelectric actuator 2c becomes short, whereby the 2 nd surface moves in the-Z direction. The 3 rd and 4 th surfaces move in the-Z direction with the movement of the 2 nd surface. In this case, the mirror surface 1sf moves only in the-Z direction. The movement of each surface is a movement in a case where the reference surface is set as a reference.

Fig. 12 is a conceptual diagram 2 for explaining a change in the shape of the variable shape mirror 10c shown in fig. 10. In the shape change shown in fig. 12, a voltage higher than that in the initial state is applied to the 1 st piezoelectric actuator 2a, thereby making the 1 st piezoelectric actuator 2a longer than that in the initial state. Fig. 12 shows the shape variable mirror 10c in the initial state and the shape variable mirror 10c in which the 1 st piezoelectric actuator 2a is long compared to the initial state. Before and after changing the length of the 1 st piezoelectric actuator 2a, the position of the 2 nd surface in the Z-axis direction does not change. The position of the X-axis member 5C in the Z-axis direction does not change, and therefore the positions of the X-axis intersection points Pxf1, Pxf2 in the Z-axis direction at which the boss bottom surfaces 5Cj1, 5Cj2 in the mirror surface 1sf contact do not change. The 1 st piezoelectric actuator 2a becomes long, and thereby the 3 rd surface moves in the + Z direction. By moving the Y-axis member 4C in the + Z direction, Yb-axis intersections Pyb1 and Pyb2 of the back surface 1sb, which the Y-axis foot bottom surfaces 4Cc1 and 4Cc2 contact, move in the + Z direction.

The positions of the X-axis intersections Pxf1, Pxf2 in the Z-axis direction do not change, and the Yb-axis intersections Pyb1, Pyb2 move in the + Z direction, whereby the mirror surface 1sf of the circular mirror 1 deforms in a saddle shape as shown in fig. 5. However, the mirror surface center 1e moves in the + Z direction along with the deformation of the mirror surface 1 sf.

Fig. 13 is a conceptual diagram 3 for explaining a change in the shape of the variable shape mirror 10c shown in fig. 10. In the shape change shown in fig. 13, the 1 st piezoelectric actuator 2a is made longer than the initial state, and the 2 nd piezoelectric actuator 2c is made shorter than the initial state. Fig. 13 shows the shape variable mirror 10c in the initial state and the shape variable mirror 10c in which the length of the 1 st piezoelectric actuator 2a and the length of the 2 nd piezoelectric actuator 2c are changed from the initial state. The length of extension of the 1 st piezoelectric actuator 2a is adjusted to be 2 times the length of shortening of the 2 nd piezoelectric actuator 2 c.

The 2 nd face is moved in the-Z direction by shortening the 2 nd piezoelectric actuator 2 c. The 3 rd surface moves in the + Z direction by the extension of the 1 st piezoelectric actuator 2a and the contraction of the 2 nd piezoelectric actuator 2 c. The extended length of the 1 st piezoelectric actuator 2a is 2 times the shortened length of the 2 nd piezoelectric actuator 2c, and thus the length of movement of the 3 rd surface in the + Z direction is the same as the length of movement of the 2 nd surface in the-Z direction. Thus, the distance changing unit 2 moves the Y-axis back plate 4Ca in the + Z direction and moves the X-axis back plate 5Ca in the-Z direction, thereby moving the Y-axis back plate 4Ca and the X-axis back plate 5Ca in opposite directions to each other in the Z-axis direction. The distance changing unit 2 moves the Y-axis back plate 4Ca and the X-axis back plate 5Ca in the Z-axis direction in opposite directions to each other, and changes the distance between the Y-axis back plate 4Ca and the circular mirror 1 symmetrically with the distance between the X-axis back plate 5Ca and the circular mirror 1. The distance changing unit 2 changes the distance between the Y-axis back plate 4Ca and the circular mirror 1 by the same amount as the distance between the X-axis back plate 5Ca and the circular mirror 1 symmetrically. The Y-axis pins 4Cb1 and 4Cb2 move in the + Z direction in accordance with the movement of the Y-axis back plate 4Ca in the + Z direction. The X-axis legs 5Cb1 and 5Cb2 move in the-Z direction in accordance with the movement of the X-axis back plate 5Ca in the-Z direction.

By moving the Y-axis pins 4Cb1 and 4Cb2 in the + Z direction, the Yb-axis intersection points Pyb1 and Pyb2, which the Y-axis pin bottom surfaces 4Cc1 and 4Cc2 contact in the back surface 1sb, move in the + Z direction. When the X-axis legs 5Cb1 and 5Cb2 move in the-Z direction, the X-axis intersections Pxf1 and Pxf2 of the mirror surface 1sf, which the bottom surfaces 5Cj1 and 5Cj2 of the protrusions contact, move in the-Z direction. The movement lengths of the Yb-axis intersections Pyb1 and Pyb2 in the + Z direction are the same as the movement lengths of the X-axis intersections Pxf1 and Pxf2 in the-Z direction.

Fig. 14 is a conceptual diagram for explaining a change in shape of the circular mirror 1 included in the variable-shape mirror 10c shown in fig. 10. The Yb-axis intersections Pyb1 and Pyb2 move in the + Z direction, and the X-axis intersections Pxf1 and Pxf2 move in the-Z direction, whereby the mirror surface 1sf of the circular mirror 1 deforms in a saddle shape. Further, since the movement lengths of the Yb axis intersections Pyb1 and Pyb2 in the + Z direction and the movement lengths of the X axis intersections Pxf1 and Pxf2 in the-Z direction are the same, the position of the mirror surface center 1e in the Z axis direction does not change. Thus, the shape-variable mirror 10c can suppress a change in the position of the mirror surface center 1e in the Z-axis direction due to the deformation of the mirror surface 1 sf.

The extended length of the 1 st piezoelectric actuator 2a may not be 2 times the shortened length of the 2 nd piezoelectric actuator 2 c. The shape variable mirror 10c can suppress a change in the position of the mirror surface center 1e in the Z-axis direction by shortening the 2 nd piezoelectric actuator 2c in accordance with the extension of the 1 st piezoelectric actuator 2a or by extending the 2 nd piezoelectric actuator 2c in accordance with the shortening of the 1 st piezoelectric actuator 2 a.

The rigidity of the circular mirror 1, the shaft member 5C of the Y-shaft member 4C, X, and the holding member 6 is adjusted to a degree that allows shape change by adjusting the material and structure. For example, if the rigidity of the Y-axis member 4C, X, the axis member 5C, and the holding member 6 is smaller than the rigidity of the circular mirror 1, the ratio of the deformation of the circular mirror 1 to the change in the distance by the distance changing unit 2 is small, and the fine deformation control of the circular mirror 1 can be realized.

The shape variable mirror 10c can suppress a change in the reflection position when applied to correction of astigmatism of a laser beam in a laser processing apparatus or correction of astigmatism in an apparatus other than the laser processing apparatus. Thereby, the shape variable mirror 10c can reduce the optical axis shift caused by the change of the reflection position. In the presence of astigmatism, the laser beam shape becomes elliptical. The shape variable mirror 10c is rotated about the Z axis in the barrel holder that fixes the holding member 6, and the direction of the major axis or the direction of the minor axis of the ellipse of the laser beam shape is made to coincide with the X axis or the Y axis of the shape variable mirror 10 c.

Here, the 2 nd piezoelectric actuator 2c is made shorter from the initial state, and the 1 st piezoelectric actuator 2a is made longer from the initial state, and deformation of the circular mirror 1 is attempted. The extension length of the 1 st piezoelectric actuator 2a is adjusted to 2 times the shortening length of the 2 nd piezoelectric actuator 2 c. When the laser beam shape approaches a perfect circle from the ellipse due to the deformation of the circular mirror 1, the amount of deformation of the circular mirror 1 is adjusted until the laser beam shape becomes a perfect circle by the shape-variable mirror 10c without changing the rotational position of the shape-variable mirror 10c in the barrel holder.

On the other hand, when the degree of flattening of the ellipse of the laser beam shape is increased by the deformation of the circular mirror 1, the shape variable mirror 10c is rotated by 90 degrees in the barrel holder, and the deformation of the circular mirror 1 due to the shortening of the 2 nd piezoelectric actuator 2c and the extension of the 1 st piezoelectric actuator 2a is attempted. As described above, the shape of the circular mirror 1 is adjusted so that the laser beam shape approaches a perfect circle by changing the length of the 1 st piezoelectric actuator 2a and the length of the 2 nd piezoelectric actuator 2c while monitoring the laser beam shape. The shape variable mirror 10c can perform adjustment by extension of the 2 nd piezoelectric actuator 2c and contraction of the 1 st piezoelectric actuator 2a, similarly to adjustment by contraction of the 2 nd piezoelectric actuator 2c and extension of the 1 st piezoelectric actuator 2 a.

The shape-variable mirror 10c according to embodiment 4 has a circular cross-sectional shape perpendicular to the Z-axis direction. Since the shape of the cross section of the shape-variable mirror 10c is circular, the shape-variable mirror 10c can be easily adjusted to be rotated based on the change in the flatness of the laser beam shape. In the present invention, the shape of the cross section of the shape-variable mirror 10c may be a shape other than a circle.

Embodiment 5.

In embodiment 5, a description will be given of a configuration in which the piezoelectric actuator of embodiment 4 is replaced with a circular mirror 1 deformed by the same adjustment screw as that of embodiment 2. Fig. 15 is an assembly diagram for explaining the structure of the shape variable mirror according to embodiment 5 of the present invention. In embodiment 5, the same components as those in embodiments 1 to 4 are denoted by the same reference numerals. In embodiment 5, the description overlapping with embodiments 1 to 4 is omitted.

The variable shape mirror 10D shown in fig. 15 includes the circular mirror 1 and the deforming-force generating mechanism portion 3D. The deformation force generation mechanism 3D generates a force to deform the mirror surface 1sf in a saddle shape. The deformation force generating mechanism 3D includes a Y-axis member 4D, X, an axis member 5D, a holding member 6A, an adjusting screw 7 as a distance changing unit, and rotation stopping members 8 and 8A. The adjusting screw 7 has a 1 st screw 7a screwed into the Y-axis back plate 4Da, a 2 nd screw 7b screwed into the X-axis back plate 5Da, and a 3 rd screw 7c screwed into the holding member 6A. The 1 st screw 7a, the 2 nd screw 7b and the 3 rd screw 7c are different in pitch from each other. The adjustment screws 7 change the distance between the Y-axis back plate 4Da and the circular mirror 1 symmetrically to the distance between the X-axis back plate 5Da and the circular mirror 1. The adjustment screws 7 change the distance between the Y-axis back plate 4Da and the circular mirror 1 by the same amount symmetrically to the distance between the X-axis back plate 5Da and the circular mirror 1.

The Y-shaft member 4D has: a Y-axis back plate 4Da which is circular with the same diameter as the circular mirror 1 and has a thickness; and Y-axis legs 4Cb1, 4Cb 2. The Y-axis back plate 4Da is a 1 st plate portion opposed to the back surface 1sb of the circular mirror 1. The Y-axis legs 4Cb1 and 4Cb2 are 1 st leg portions extending in the + Z direction from the Y-axis back plate 4Da and abutting against the rear surface 1sb of the circular mirror 1. The Y-axis screw hole 4Df is provided at the center of the Y-axis back plate 4 Da. The 1 st screw 7a is screwed into the Y-axis screw hole 4 Df. The Y-axis member positioning holes 4Dg1 and 4Dg2 are provided on the outer side of the Y-axis back plate 4Da in the radial direction than the Y-axis screw hole 4Df and on the inner side of the cutouts 4Cd1 and 4Cd2 in the radial direction. The columnar portions 8c and 8Ac of the rotation stopper members 8 and 8A are inserted into the Y-axis member positioning holes 4Dg1 and 4Dg2, respectively. In embodiment 5, the notches 4Cd1 and 4Cd2 may not be provided.

The X-axis member 5D includes: an X-axis back plate 5Da which is circular in diameter larger than the circular mirror 1 and has a thickness; and X-axis legs 5Cb1, 5Cb 2. The X-axis back plate 5Da is a 2 nd plate portion opposed to the Y-axis back plate 4 Da. The X-axis legs 5Cb1 and 5Cb2 are the 2 nd leg which extends from the X-axis back plate 5Da across the Y-axis member 4D and abuts against the mirror surface 1sf of the circular mirror 1. The X-axis screw hole 5Df is provided at the center of the X-axis back plate 5 Da. The 2 nd screw 7b is screwed into the X-axis screw hole 5 Df. The positioning holes 5Dg1 and 5Dg2 are provided on the outer side of the X-axis back plate 5Da in the radial direction than the X-axis screw hole 5Df and on the inner side of the X-axis legs 5Cb1 and 5Cb2 in the radial direction. The columnar portions 8c, 8Ac of the rotation stop members 8, 8A are inserted into the positioning holes 5Dg1, 5Dg2, respectively.

The holding member 6A holds the Y-axis member 4D and the X-axis member 5D via the adjustment screws 7. The rotation preventing members 8 and 8A prevent rotational displacement of the Y-axis member 4D and the X-axis member 5D about the Z-axis with respect to the holding member 6A. Further, the deforming-force-generating mechanism portion 3D is not limited to having 2 rotation-stopping members 8, 8A. The number of the rotation stop members may be any number as long as the rotation deviation of the Y-axis member 4D and the X-axis member 5D can be prevented.

Next, deformation of the mirror surface 1sf of the circular mirror 1 into a saddle shape will be described. In the following description, the reference surface is a surface of the holding member 6A on the circular mirror 1 side. The 2 nd surface is a surface of the X-axis back plate 5Da on the circular mirror 1 side. The 3 rd surface is a surface of the Y-axis back plate 4Da on the X-axis back plate 5Da side. The 4 th surface is a rear surface 1sb of the circular mirror 1.

The center of the Y-axis back plate 4Da and the center of the X-axis back plate 5Da pass through the center of the circular mirror 1 and exist on a straight line perpendicular to the circular mirror 1. The deformation force generation mechanism 3D changes the amount of insertion of the 1 st screw 7a into the Y-axis screw hole 4Df on the straight line, thereby changing the interval between the X-axis back plate 5Da and the Y-axis back plate 4 Da. The deformation force generation mechanism 3D changes the amount of insertion of the 3 rd screw 7c into the holding member screw hole 6Af on the straight line, thereby changing the distance between the holding member 6A and the X-axis back plate 5 Da.

The deforming force generating mechanism 3D is configured such that the difference between the total length of the circular mirror 1, the Y-axis legs 4Cb1, 4Cb2, and the Y-axis back plate 4Da in the Z-axis direction and the length between the 2 nd surface and the bottom surfaces 5Cj1, 5Cj2 is equal to a set length. The set length is a length of the 1 st screw 7a from the 2 nd surface in the Z-axis direction when the center of the 1 st screw 7a in the Z-axis direction coincides with the center of the Y-axis back plate 4Da in the Z-axis direction and the center of the 2 nd screw 7b in the Z-axis direction is the center of the X-axis back plate 5Da in the Z-axis direction.

Next, the pitch of the 1 st screw 7a, the 2 nd screw 7b, and the 3 rd screw 7c will be described. In embodiment 5, the difference Pc-Pb obtained by subtracting the pitch width Pb of the 2 nd screw 7b from the pitch width Pc of the 3 rd screw 7c and the difference Pc-Pa obtained by subtracting the pitch width Pa of the 1 st screw 7a from the pitch width Pc of the 3 rd screw 7c are opposite in polarity. In the case where the pitch width Pb is larger than the pitch width Pc, the pitch width Pa is set smaller than the pitch width Pc. The absolute value of Pc-Pb, which is the difference between the pitch width Pc and the pitch width Pb, is equal to the absolute value of Pc-Pa, which is the difference between the pitch width Pc and the pitch width Pa. Next, in setting the pitch widths Pa, Pb, and Pc, the deformation of the circular mirror 1 when the adjustment screw 7 is rotated will be described.

If the adjustment screw 7 is rotated 1 rotation in the direction of screwing in the + Z direction, the adjustment screw 7 moves in the + Z direction with respect to the reference surface by a length corresponding to the pitch width Pc of the 3 rd screw 7 c. At this time, the X-axis back plate 5Da moves in the-Z direction with respect to the reference surface by a length corresponding to the pitch width Pb of the 2 nd screw 7 b. The pitch width Pc is smaller than the pitch width Pb, so the X-axis back plate 5Da moves in the-Z direction with respect to the screw reference plane by a length corresponding to Pc-Pb. Here, the screw reference surface is a surface parallel to the XY direction which is the horizontal direction in the adjustment screw 7. The screw reference surface is, for example, a plane of a step constituting a boundary between the 2 nd screw 7b and the 3 rd screw 7 c. The screw reference surface is not limited to this plane, and may be a surface parallel to the horizontal direction.

The Y-axis back plate 4Da moves in the + Z direction with respect to the reference surface by a length corresponding to the pitch width Pa of the 1 st screw 7 a. The pitch width Pc is larger than the pitch width Pa, and therefore the Y-axis back plate 4Da moves in the + Z direction with respect to the screw reference surface by a length corresponding to Pc-Pa. The Y-axis pins 4Cb1 and 4Cb2 move in the + Z direction in accordance with the movement of the Y-axis back plate 4Da in the + Z direction. The X-axis legs 5Cb1 and 5Cb2 move in the-Z direction in accordance with the movement of the X-axis back plate 5Da in the-Z direction.

By moving the Y-axis pins 4Cb1 and 4Cb2 in the + Z direction, the Yb-axis intersection points Pyb1 and Pyb2, which the Y-axis pin bottom surfaces 4Cc1 and 4Cc2 contact in the back surface 1sb, move in the + Z direction. When the X-axis legs 5Cb1 and 5Cb2 move in the-Z direction, the X-axis intersections Pxf1 and Pxf2 of the mirror surface 1sf, which the bottom surfaces 5Cj1 and 5Cj2 of the protrusions contact, move in the-Z direction. The movement lengths of the X-axis intersections Pxf1 and Pxf2 in the-Z direction are the same as the movement lengths of the Yb-axis intersections Pyb1 and Pyb2 in the + Z direction.

The X-axis intersections Pxf1 and Pxf2 move in the-Z direction, and the Yb-axis intersections Pyb1 and Pyb2 move in the + Z direction, whereby the mirror surface 1sf of the circular mirror 1 deforms in a saddle shape. Further, since the shift lengths of the X-axis intersections Pxf1 and Pxf2 in the-Z direction and the shift lengths of the Yb-axis intersections Pyb1 and Pyb2 in the + Z direction are the same, the position of the mirror surface center 1e in the Z-axis direction does not change. Thus, the shape variable mirror 10d can suppress a change in the position of the mirror surface center 1e in the Z-axis direction due to the deformation of the mirror surface 1 sf.

As described above, when the pitch width Pb is larger than the pitch width Pc and the pitch width Pa is smaller than the pitch width Pc, the adjustment screw 7 is rotated in the direction of being screwed in the + Z direction when the mirror surface 1sf is deformed. In the pitch widths Pa, Pb, and Pc, a pitch width Pb smaller than the pitch width Pc and a pitch width Pa larger than the pitch width Pc may be set. When the pitch width Pb is smaller than the pitch width Pc and the pitch width Pa is larger than the pitch width Pc, the adjustment screw 7 is rotated in a direction to be screwed out in the-Z direction when the mirror surface 1sf is deformed.

The shape variable mirror 10d can suppress a change in the reflection position when applied to correction of astigmatism of a laser beam in a laser processing apparatus or correction of astigmatism in an apparatus other than the laser processing apparatus. Thereby, the shape variable mirror 10d can reduce the optical axis shift caused by the change of the reflection position.

Embodiment 6.

In embodiment 6, a description will be given of a configuration in which a lock mechanism similar to that in embodiment 3 is added to the configuration in embodiment 5. Fig. 16 is an assembly diagram for explaining the structure of the shape variable mirror according to embodiment 6 of the present invention. In embodiment 6, the same components as those in embodiments 1 to 5 are denoted by the same reference numerals. In embodiment 6, the description overlapping with embodiments 1 to 5 is omitted.

The shape variable mirror 10E shown in fig. 16 includes a circular mirror 1 and a deforming force generating mechanism portion 3E. The deformation force generation mechanism 3E generates a force to deform the mirror surface 1sf in a saddle shape. The deformation force generation mechanism 3E is configured by adding a lock member 9 to the structure of the deformation force generation mechanism 3D according to embodiment 5. The locking member 9 is a locking mechanism that locks the rotation of the adjustment screw 7 including the 1 st screw 7a, the 2 nd screw 7b, and the 3 rd screw 7 c. The shape-variable mirror 10e can prevent the shape of the circular mirror 1 from being restored by the rotation of the adjustment screw 7 after the circular mirror 1 is deformed by locking the rotation of the adjustment screw 7 by the locking member 9. Thereby, the shape-variable mirror 10e can stably maintain the state of the circular mirror 1 after deformation.

Embodiment 7.

In embodiment 7, the configuration of a laser processing apparatus including the shape variable mirror 10 shown in fig. 2 will be described in detail. Further, the laser processing apparatus may have the shape variable mirror 10a or the shape variable mirror 10b instead of the shape variable mirror 10. The laser processing apparatus may include a shape variable mirror 10c, a shape variable mirror 10d, or a shape variable mirror 10e instead of the shape variable mirror 10.

Fig. 17 is a diagram showing a configuration example of a laser processing apparatus according to embodiment 7 of the present invention. The laser processing apparatus 100 shown in fig. 17 includes: a laser oscillator 50 which is a light source of the laser beam LB; a mirror group including a plurality of mirrors, not shown, including a shape variable mirror 10, and forming a transmission optical path of the laser beam LB emitted from the laser oscillator 50; 2 electrically controlled scanning mirrors 20 for scanning the laser beam LB from the transmission optical path in a 2-dimensional direction perpendicular to the optical axis; a condensing lens 60 that condenses the laser beam LB scanned by the galvano-mirror 20 before irradiating the workpiece 200; a table 70 on which a workpiece 200 is placed; and a driving mechanism 80 that drives the table 70 in the 2-dimensional direction.

Further, galvanometers 21 which are independently rotationally driven are connected to the 2 electronically controlled scanning mirrors 20.

Further, an astigmatism adjusting device 11 is connected to the shape variable mirror 10, and the astigmatism adjusting device 11 adjusts the amount of deformation of the circular mirror 1 included in the shape variable mirror 10 and the orientation of the shape variable mirror 10 itself in accordance with the state of the laser beam LB oscillated from the laser oscillator 50.

The rotation number and angle adjustment of the astigmatism adjusting device 11 can be realized by a stepping motor, for example.

Note that, if the amount of deformation of the circular reflecting mirror 1 included in the shape variable mirror 10 and the direction of the shape variable mirror 10 itself can be adjusted manually, the astigmatism adjustment device 11 may not be provided.

Next, an operation example of the laser processing apparatus 100 will be described. The laser beam LB emitted from the laser oscillator 50 is transmitted by a plurality of mirrors, not shown, including the variable shape mirror 10, is 2-dimensionally scanned by 2 galvano-mirrors 20, and is positioned on the workpiece 200 by the condenser lens 60 to be irradiated. A rectangular region Rw surrounded by a broken line on the workpiece 200 shows a processing region by beam scanning. The table 70 on which the workpiece 200 is placed can be moved in a range in a 2-dimensional direction perpendicular to the beam axis by a drive mechanism 80 having drive portions 81 and 82 that drive in directions orthogonal to each other.

In this machining optical system, the variable shape mirror 10 is used as one of the mirrors, and the astigmatism is corrected, whereby the roundness of the machined hole during laser machining is improved, and the depth of focus is increased due to the reduction of the astigmatism. At this time, as described in embodiment 1 above, even if the astigmatism is corrected by the variable shape mirror 10, the change of the mirror surface center 1e in the mirror surface 1sf of the circular reflecting mirror 1 in the height direction, that is, the Z direction is suppressed, and therefore, even if the astigmatism is corrected, the deviation of the optical axis of the light beam reflected from the variable shape mirror 10 is suppressed.

The shape-variable mirror 10 does not necessarily have to be arranged at the position shown in fig. 17, and the shape-variable mirror 10 may be applied to a mirror at another position in the optical path.

In the laser processing apparatus 100 shown in fig. 17, both the laser beam LB and the table 70 can perform 2-dimensional scanning, but the present invention is not limited thereto. The variable shape mirror 10 acts on astigmatism of the processing optical system and is not affected by the scanning method. That is, in the case where the laser beam LB, the condenser lens 60, and the stage 70 perform 1-dimensional, 2-dimensional, or 3-dimensional scanning or in the case of a laser processing apparatus in which they do not perform scanning, the astigmatism applied to the variable shape mirror 10 can be corrected.

Further, the laser beam LB may be any of single pulse, multi-pulse, or continuous oscillation.

The machining by the laser machining apparatus 100 is not limited to the hole drilling, and may be cutting, deformation, welding, heat treatment, or marking, as long as the machining is changed by the laser beam such as burning, melting, sublimation, or discoloration of the workpiece 200.

As described in embodiments 1 to 6, since the mirror surface 1sf can be deformed into a saddle shape without being bonded and can be fixed so that the deformation amount does not change even if vibration occurs, astigmatism of the laser beam LB can be corrected and the processing accuracy of the laser processing apparatus 100 can be improved. In the above description, the deformed shape of the circular mirror 1 is described as a saddle shape, but may be a semicircular cone shape.

As described above, according to the laser processing apparatus 100 including the shape variable mirrors 10, 10a, 10b, 10c, 10d, and 10e according to embodiments 1 to 6, astigmatism of the laser beam LB can be corrected to improve the processing accuracy of the laser processing apparatus 100.

The configuration described in the above embodiment is an example of the content of the present invention, and may be combined with other known techniques, and a part of the configuration may be omitted or modified without departing from the scope of the present invention.

Description of the reference numerals

1 circular mirror, 2 distance changing part, 2a 1 st piezoelectric actuator, 2B piezoelectric actuator connecting part, 2C 2 nd piezoelectric actuator, 3A, 3B, 3C, 3D, 3E deformation force generating mechanism part, 4A, 4C, 4D Y shaft parts, 4A, 4Aa, 4Ca, 4Da Y shaft back plate, 4B D Y, 4Ab D Y, 4Cb 2D Y shaft leg, 4C D Y, 4Ac D Y, 4Cc 2D Y shaft leg bottom surface, 4D D Y, 4Ad D Y, 4Cd D Y notch, 4Af, 4Df shaft screw hole, 4Ag D Y, 4Dg D Y, 4Dg 2D Y, 4Dg 5A, 5C D Y, 5Cb 5C shaft part, 5Cb D Y, 5Cb 3, 5C D Y, 5Cb D Y, 5C shaft back plate, 4Ac D Y, 4Ab 5B D Y, 4Cb 5C D Y, 5B D Y, 4Cb 5B D Y, 4Cc D Y, 5B D Y, 5C shaft part, 5B 36, 5Ac2X shaft base bottom surface, 5f, 5Cf through hole, 5Af, 5Df X shaft screw hole, 5Ag1, 5Ag2, 5Dg1, 5Dg2 positioning hole, 5Ch1, 5Ch2 boss, 5Cj1, 5Cj2 boss bottom surface, 6A holding member, 6Af holding member screw hole, 6Ag1, 6Ag2 holding member positioning hole, 7 adjusting screw, 7a 1 st screw, 7b 2 nd screw, 7c 3 rd screw, 8A rotation stopping member, 8c, 8Ac cylindrical portion, 8d, 8Ad head, 9 locking member, 10a, 10b, 10c, 10d, 10e shape variable mirror, 11 astigmatism adjusting device, 20 electric control scanning mirror, 21 galvanometer, 50 laser, 60 condenser lens, 80 driving mechanism, 81, 82 driving portion, 100 laser processing device, 200 laser processing object.

Claims (8)

1. A shape-variable mirror, comprising:

a mirror having a reflective surface;

a 1 st member having a 1 st plate portion facing a rear surface of the reflection surface in the mirror, and 21 st leg portions extending from the 1 st plate portion and coming into contact with the mirror;

a 2 nd member having a 2 nd plate portion facing the 1 st plate portion, and 2 nd leg portions extending from the 2 nd plate portion across the 1 st member and coming into contact with the mirror;

a distance changing unit that changes a distance between the 1 st plate unit and the mirror symmetrically with respect to a distance between the 2 nd plate unit and the mirror; and

a holding member that holds the 1 st member and the 2 nd member via the distance changing portion,

in the reflector, a line segment connecting portions where the 21 st leg portions abut and a line segment connecting portions where the 2 nd leg portions abut intersect.

2. The shape variable mirror according to claim 1,

the 21 st foot parts and the 2 nd 2 foot parts are fixed on the back surface.

3. The shape variable mirror according to claim 1,

the 21 st feet are in contact with the back face,

the 2 nd foot is in contact with the reflective surface.

4. The shape variable mirror according to any one of claims 1 to 3,

the distance changing unit changes a distance between the 2 nd plate unit and the mirror by the same amount as a distance between the 1 st plate unit and the mirror.

5. The shape variable mirror according to any one of claims 1 to 3,

the distance changing unit includes: a fixing portion fixed to the 2 nd plate portion; a 1 st piezoelectric actuator which is in contact with the 1 st plate section and is capable of expanding and contracting between the fixing section and the 1 st plate section; and a 2 nd piezoelectric actuator which is in contact with the holding member and is capable of expanding and contracting between the fixing portion and the holding member.

6. The shape variable mirror according to any one of claims 1 to 3,

the distance changing part comprises a 1 st screw screwed into the 1 st plate part, a 2 nd screw screwed into the 2 nd plate part, and a 3 rd screw screwed into the holding member,

the difference obtained by subtracting the pitch of the 2 nd screw from the pitch of the 3 rd screw is opposite in sign to the difference obtained by subtracting the pitch of the 1 st screw from the pitch of the 3 rd screw.

7. The shape variable mirror according to claim 6,

the screw driver includes a locking mechanism that locks rotation of the 1 st screw, the 2 nd screw, and the 3 rd screw.

8. A laser processing apparatus is characterized by comprising:

a laser oscillator that oscillates a laser beam;

a setting table for setting a workpiece; and

a transmission optical path having a plurality of mirrors for transmitting the laser beam oscillated from the laser oscillator to the workpiece disposed on the mounting table,

the plurality of mirrors are the shape variable mirrors of any one of claims 1 to 7.

Images