Reflecting mirror device and reflecting mirror surface adjusting system

Abstract

The present invention includes: a reflecting mirror (1) having a mirror surface (1A), three supported spots (1C) provided on a rear surface of the mirror surface (1A), and a predetermined total number of shape-correction spots (1D) provided on the rear surface; a structural member (2) that supports the reflecting mirror; three support units (5) that are connected to each of the supported spots (1C) and support the reflecting mirror (1); and a shape-correction unit (6) that changes a position of each of the shape-correction spots (1D) in an optical-axis direction of the reflecting mirror (1); in which the shape-correction unit (6) has a link member (6B) provided rotatably around a fulcrum (6D) provided on a column, a rod-shaped member (6A) having one end connected to the shape-correction spot (1D) and the other end attached to the link member (6B), and a link-drive unit (8) provided at a position with a distance to the fulcrum (6D) larger than that at a spot where the rod-shaped member (6A) is attached on the link member (6B) on a side opposite to the rod-shaped member (6A) with respect to the fulcrum (6D).

Description

Reflector device and reflector surface adjustment system

[0001] The present disclosure relates to a reflector device used in a telescope and a reflector surface adjustment system for adjusting the shape of the reflector surface.

[0002] To achieve high mirror surface accuracy, the main reflector of a telescope is rigidly supported to avoid over-constraint. Rigid support prevents excessive internal forces and deformations from occurring inside the main reflector, improving the surface accuracy of the main reflector and achieving high telescope performance. However, even in a rigidly supported main reflector, small deformation modes remain. Factors that cause small deformation modes to remain in the main reflector include manufacturing errors of the main reflector itself, the influence of its own weight, assembly errors, and misalignment with other optical devices.

[0003] There is a mirror active support system that uses actuators to push and pull the back surface of a rigidly supported mirror at multiple locations (several tens to hundreds) to compensate for minute deformation modes of the main reflector (see, for example, Patent Document 1). This mirror active support system is used in the Subaru Telescope, a large optical telescope with an aperture of 8.2 m installed on the island of Hawaii. In Patent Document 1, the mirror active support system calculates the distortion of the reflector surface due to its own weight without measuring the mirror shape, and compensates for the calculated distortion. The support mechanism of the mirror active support system linearly pushes and pulls the back surface of the reflector.

[0004] To compensate for deformation of the reflector due to its own weight, there is a reflector support mechanism equipped with multiple lever mechanisms on the bottom and side surfaces of the reflector device (see, for example, Patent Document 2). The lever mechanism has a load shaft that supports the reflector on one side of an arm supported by a fulcrum, and a weight on the other side of the arm that balances the weight that the load shaft receives from the reflector.

[0005] There is a reflector adjustment mechanism that can adjust the tilt height of a thin, lightweight reflector without causing harmful deformation, and can also relieve thermal deformation while suppressing the generation of thermal stress (see, for example, Patent Document 3).

[0006] Japanese Patent Publication No. 7-034058, Japanese Patent Application Laid-Open No. 3-068908, and Japanese Patent Application Laid-Open No. 2001-296466

[0007] Telescopes used in space are expected to have a reflector device that can actively adjust the shape of the mirror surface. A reflector device that can actively adjust the shape of the mirror surface would allow the mirror surface to be shaped as intended with high precision, even when there are temperature changes, for example. By increasing the precision of the main reflector's surface, the telescope's high performance can be fully realized.

[0008] The support mechanism of the mirror surface active support device of Patent Document 1 displaces linearly, so it needs to have a drive mechanism that can generate the force required for displacement. As a result, each support mechanism becomes heavy. The more supported points there are, the higher the mirror surface accuracy becomes, so the number of support mechanisms is large to achieve the required mirror surface accuracy. As a result, reflector devices that can actively adjust the shape of the mirror surface used on the ground are large in size and heavy. If they are too heavy, they cannot be launched into space. There is a demand for a reflector device that is light enough to be launched into space and whose mirror surface shape can be adjusted to the intended shape even in space.

[0009] An object of the present disclosure is to provide a reflector device that is lighter than conventional devices and whose mirror surface shape can be adjusted to an intended shape even in outer space.

[0010] The reflector device according to the present disclosure comprises a reflector having a mirror surface that reflects electromagnetic waves, three supported locations on the back surface of the mirror surface, and a predetermined total number of shape correction locations on the back surface, a structural member located on the back side of the reflector opposite to the side where the mirror surface is present and supporting the reflector, three support parts located on the structural member and connected to each of the supported locations to support the reflector, and shape correction parts located on the structural member, the number of which is equal to the number of shape correction locations, and which change the positions of each shape correction location in an optical axis direction that is a direction parallel to the optical axis of the reflector. The shape correction parts include a support post located on the back surface, which is the surface of the structural member opposite to the side where the reflector is present, a link member rotatable about a fulcrum located on the support post, a rod-shaped member having one end connected to the shape correction locations and the other end attached to the link member, and a link drive part located on the link member opposite to the location where the rod-shaped member is attached at a position greater than the location where the rod-shaped member is attached and which generates a force to move the link member in the optical axis direction.

[0011] According to the reflector device of the present disclosure, it is possible to obtain a reflector device that is lighter than conventional ones and whose mirror surface shape can be adjusted to the intended shape even in outer space.

[0012] 1 is a perspective view of a reflector device according to embodiment 1, as seen obliquely from above. FIG. 2 is a perspective view of a reflector device according to embodiment 1, as seen obliquely from below. FIG. 3 is a perspective view of a reflector device according to embodiment 1, as seen obliquely from above, with the main reflector removed. FIG. 4 is a perspective view of an actuator and a rear disk member provided in the reflector device according to embodiment 1, as seen obliquely from below. FIG. 5 is a plan view of a reflector device according to embodiment 1. FIG. 6 is a front view of a reflector device according to embodiment 1. FIG. 7 is a bottom view of a reflector device according to embodiment 1. FIG. 8 is a horizontal cross-sectional view of a reflector device according to embodiment 1. FIG. 9 is a bottom view of a reflector device according to embodiment 1, with the rear disk member and rear structural frame removed. FIG. 10 is a bottom view showing the arrangement of actuators in the reflector device according to embodiment 1. FIG. 11 is a schematic vertical cross-sectional view of a reflector device according to embodiment 1. FIG. 12 is a schematic cross-sectional view showing actuators provided in the reflector device according to embodiment 1. FIG. 13 is a side view of a reflector device according to embodiment 1. FIG. 14 is an enlarged side view of a reflector device according to embodiment 1. FIG. 15 is a bottom view of a shape adjustment actuator provided in the reflector device according to embodiment 1. FIG. 16 is a horizontal cross-sectional view of a shape adjustment actuator provided in the reflector device according to embodiment 1. 1 is a diagram illustrating the structure of a pivot member of a shape adjustment actuator provided in a reflecting mirror device according to embodiment 1. FIG. 2 is another side view of a reflecting mirror device according to embodiment 1. FIG. 3 is another enlarged side view of a reflecting mirror device according to embodiment 1. FIG. 4 is another enlarged side view of a reflecting mirror device according to embodiment 1, with a portion cut away showing the inside of a support actuator. FIG. 5 is a diagram illustrating the Zenikel mode of a mirror surface. FIG. 6 is a schematic diagram illustrating the configuration of a reflecting mirror surface adjustment system that adjusts the mirror surface of a reflecting mirror device according to embodiment 1. FIG. 7 is a flowchart illustrating the procedure from launching a telescope having a reflecting mirror device according to embodiment 1 into space to using it for observation. FIG. 8 is a flowchart illustrating the procedure from installing a telescope having a reflecting mirror device according to embodiment 1 on Earth to using it for observation.

[0013] Embodiment 1. The structure of a reflector device according to the present disclosure will be described with reference to Figures 1 to 10. The reflector device according to the present disclosure is a reflector device that is part of a telescope used in outer space. Figures 1 and 2 are perspective views of the reflector device according to embodiment 1, viewed obliquely from above or below. Figure 3 is a perspective view of the reflector device with the main reflector removed, viewed obliquely from above. Figure 4 is a perspective view of the actuator and back disk member of the reflector device, viewed obliquely from below. Figures 5 to 7 are plan, front, and bottom views of the reflector device.

[0014] Fig. 8 is a horizontal cross-sectional view of the reflector device. Fig. 8 is a cross-sectional view taken along the line AA shown in Fig. 6. The line AA is a horizontal cross-section. Fig. 8 is a cross-sectional view looking up from below. Fig. 9 is a bottom view of the reflector device with the rear disc member and rear structural frame removed. Fig. 10 is a schematic cross-sectional view of the reflector device viewed from the side opposite to the front. Fig. 10 is a bottom view showing the arrangement of actuators in the reflector device.

[0015] The reflector device 50 according to the first embodiment mainly comprises a main reflector 1, a rear disk member 2, a rear structure frame 3, a connecting member 4, a support actuator 5, and a shape correction actuator 6. The main reflector 1 has a concave mirror surface 1A that reflects observation light. The rear disk member 2 is located on the rear side, opposite the side on which the mirror surface 1A of the main reflector 1 is located, and is a structural member that supports the main reflector 1. The rear structure frame 3 is located on the rear side of the rear disk member 2 and is a structural member that supports the rear disk member 2. The connecting member 4 is a cylindrical member with a flange that connects the rear disk member 2 and the rear structure frame 3. The rear disk member 2, the rear structure frame 3, and the connecting member 4 can be considered as structural members that support the main reflector 1. The surfaces of the rear disk member 2 and the rear structure frame 3 opposite the side on which the main reflector 1 is located are called the rear sides.

[0016] The support actuator 5 is an actuator that supports the main reflector 1 and is also used to correct the shape of the mirror surface 1 A. The shape correction actuator 6 is an actuator that is used to correct the shape of the mirror surface 1 A. The support actuator 5 and the shape correction actuator 6 push and pull the back surface of the main reflector 1 using a lever mechanism.

[0017] The main reflecting mirror 1 has a circular shape when viewed in the optical axis direction, which is the direction in which the optical axis LX (shown in FIGS. 1 and 11) extends. As shown in FIG. 9, the back surface of the main reflecting mirror 1 is provided with a rib 1B, three supported portions 1C, and 18 corrected portions 1D. Multiple reinforcing ribs 1B are provided in each of three directions that form angles of 60 degrees with each other. In each direction, the ribs 1B are provided at equal intervals. The ribs 1B in the three directions intersect at one point.

[0018] A telescope using the reflector device 50 is an optical telescope that uses visible light as observation light. It may also be a telescope that observes electromagnetic waves of wavelengths such as infrared light or radio waves. The mirror surface 1A reflects the electromagnetic waves to be observed. The supported points 1C are supported points provided on the back surface of the main reflector 1. The corrected points 1D are a set total number of shape correction points provided on the back surface. The number of all corrected points 1D is called the total number. For the main reflector 1, the total number is set to 18. The main reflector 1 is a reflector that has a mirror surface 1A that reflects electromagnetic waves, three supported points provided on the back surface, which is the surface opposite to the mirror surface 1A, and a set total number of shape correction points provided on the back surface.

[0019] The support actuators 5 are support parts that are provided on the structural members and connected to each supported point to support the reflecting mirror. The shape correction actuators 6 are shape correction parts that are provided on the structural members and change the position of each shape correction point in the optical axis direction, which is a direction parallel to the optical axis LX of the reflecting mirror. The support actuators 5 also function as shape correction parts. The reflecting mirror device 50 has three support actuators 5 and 18 shape correction actuators 6, the same number as the number of correction points 1D.

[0020] To explain the structure of the reflecting mirror device 50, an XYZ Cartesian coordinate system is defined. The Z axis is defined as parallel to the optical axis LX. The X axis is defined as parallel to one side of the triangle of the rear structure frame 3, which has a substantially triangular shape when viewed from the optical axis direction. The Y axis is defined as an axis perpendicular to the X axis in a plane perpendicular to the Z axis. The positive direction of the Z axis is defined as the upward direction, the direction from left to right in FIG. 5 is defined as the positive direction of the X axis, and the direction from bottom to top is defined as the positive direction of the Y axis.

[0021] The supported points 1C and the corrected points 1D are located at the points where the ribs 1B intersect. The supported points 1C and the corrected points 1D are circular when viewed in the optical axis direction. A spherical bearing 1E (shown in FIG. 12) is provided at the supported points 1C. The corrected points 1D have a plane perpendicular to the optical axis direction. The three supported points 1C are located at the three vertices of an equilateral triangle whose center of gravity is at the center of the outline circle of the main reflecting mirror 1 (called the mirror surface center).

[0022] The 18 corrected locations 1D are arranged on three circles centered on the mirror surface center, six on each side, with the lines connecting them to the mirror surface center forming a 60-degree angle with each other. The six corrected locations 1D on the outermost circle and the six corrected locations 1D on the innermost circle are arranged at the same angular position relative to the mirror surface center. The six corrected locations 1D on the intermediate circle are arranged at a 30-degree angle with the lines connecting the corrected locations 1D on the outer and inner circles to the mirror surface center, and at a 60-degree angle with each other with the lines connecting them to the mirror surface center. The three supported locations 1C are arranged on a circle centered on the mirror surface center, with the lines connecting them to the mirror surface center forming a 120-degree angle with each other. The circle on which the supported locations 1C are arranged is located between the innermost circle on which the corrected locations 1D are arranged and the intermediate circle. The three supported points 1C are provided at angular positions on the outermost and innermost circles where the corrected points 1D are located.

[0023] In the reflecting mirror device 50, the total number of correction locations 1D is 18. In a plane perpendicular to the optical axis direction, a circle centered at the center of the mirror surface on which the correction locations 1D are located is called a placement circle. The number of placement circles is called the number of placement circles. Each placement circle has a different radius. The number of correction locations 1D located on each placement circle is called the number of same-radius locations. In the reflecting mirror device 50, the number of placement circles is 3 and the number of same-radius locations is 6, and the total number, 18, is the product of the number of placement circles and the number of same-radius locations. The number of placement circles and the number of same-radius locations may be integers greater than or equal to 2. The number of correction locations 1D located on placement circles with different radii may be different.

[0024] On each arrangement circle, the six correction locations 1D are arranged so that the lines connecting them to the mirror surface center form 60 degrees with each other. That is, the six correction locations 1D are arranged with six-fold rotational symmetry. The six correction locations 1D arranged on the intermediate arrangement circle form angles of 30 degrees with the correction locations 1D arranged on the arrangement circles outside and inside it. Therefore, a shape correction location 1D arranged on an arrangement circle having a certain radius is arranged on the bisector of the angle formed at the mirror surface center by two line segments connecting each of the shape correction locations 1D arranged on an arrangement circle adjacent in the radial direction of the main reflector 1 to the mirror surface center.

[0025] Each of the three supported points 1C may be disposed at an angular position on the intermediate arrangement circle where the correction point 1D is located. The shape correction point 1D may be disposed on each of the three straight lines connecting each of the three supported points 1C to the center of the mirror surface.

[0026] When the reflector device 50 is on Earth, most of the load from the main reflector 1 is supported by the three supported points 1C and the three support actuators 5. Therefore, the supported point 1C is larger than the corrected point 1D. The load from the main reflector 1 is not applied very much to the corrected point 1D and the shape correction actuator 6. The shape correction actuator 6 generates a force that moves the corrected point 1D in the optical axis direction. By simultaneously displacing the three support actuators 5 by the same amount, the main reflector 1 can be moved as a single mass relative to the back disk member 2. By displacing the support actuators 5 individually, the support actuators 5 can be used to correct the shape of the mirror surface 1A.

[0027] The rear disk member 2 is disk-shaped and has a smaller diameter than the main reflecting mirror 1. A support actuator 5 and a shape correction actuator 6 are attached to the rear disk member 2. A plurality of through holes 2A are provided in the rear disk member 2. A support column 5A, which is a member of the support actuator 5 that connects to the supported portion 1C, or a rod spring 6A, which is a member of the shape correction actuator 6 that connects to the corrected portion 1D, passes through each of the plurality of through holes 2A. As shown in Figure 10 and other figures, the rear disk member 2 has a hollow structure.

[0028] When viewed from the optical axis direction, the rear structure frame 3 has the shape of a large equilateral triangle with a small equilateral triangle connected to the inside facing in the opposite direction. Frame support members 3A are provided at each vertex of the large equilateral triangle. The frame support members 3A are square tubes positioned in the optical axis direction. A secondary mirror support frame 60 (shown in Figure 1) is inserted into the frame support member 3A. The secondary mirror support frame 60 supports a secondary mirror 61 (shown in Figure 1). The secondary mirror 61 reflects the observation light reflected by the main reflecting mirror 1. The observation light reflected by the secondary mirror 61 passes through an optical path opening 1F located in the center of the main reflecting mirror 1 and an optical path opening 2B located in the center of the rear disk member 2, and enters an optical device (not shown).

[0029] The radius of the main reflector 1 is r ＭＲ Then, the radius of the arrangement circle on which the outermost correction target portion 1D is arranged is approximately 0.91*r ＭＲThe radius of the arrangement circle on which the six intermediate correction points 1D are arranged in the radial direction is approximately 0.79*r ＭＲ The radius of the arrangement circle on which the three supported points 1C are arranged is approximately 0.68*r ＭＲ The radius of the arrangement circle on which the innermost correction target portion 1D is arranged is approximately 0.45*r ＭＲ The radius of the optical path opening 1F is approximately 0.20*r ＭＲ is.

[0030] The dorsal structure frame 3 is also a structural member of the telescope including the reflector assembly 50. The telescope has a frame structure including the dorsal structure frame 3. The dorsal structure frame 3 is also a member for mounting the telescope at an installation location. As shown in Figure 10, the dorsal structure frame 3 has a hollow structure.

[0031] The rear structural frame 3 has plate-shaped connectable parts 3B, which are a combination of a semicircle and a rectangle when viewed from the optical axis direction, at the center of the three sides of the large triangle on the side of the optical axis where the main reflector 1 is located. Reinforcement ribs 3C are provided on the back side of the connectable parts 3B. One end of a connecting member 4 is connected to each of the three connectable parts 3B. The other end of the connecting member 4 is connected to the back surface of the rear disc member 2.

[0032] The central axis of the cylindrical connecting member 4 is parallel to the optical axis direction. The connecting member 4 connects the rear disk member 2 and the rear structural frame 3 at a position where the central axis of the cylindrical connecting member 4 passes through the center of the supported portion 1C. The diameter of the through hole 2A in the rear disk member 2, through which the support column 5A passes, is the same as the inner diameter of the connecting member 4. The connecting member 4 is connected to the rear surface of the rear disk member 2 so that the internal space thereof communicates with the through hole 2A.

[0033] Each of the three support actuators 5 is attached to the rear disk member 2 at a position where a support pillar 5A extending in the optical axis direction connects with the supported portion 1C. An opening 4A (reference number not shown) is provided in the connecting member 4, and the support actuators 5 are arranged to pass through the opening 4A. The support pillar 5A is located inside the connecting member 4, and the rest of the connecting member 4 is located outside the connecting member 4. Each of the 18 shape correction actuators 6 is attached to the rear disk member 2 at a position where a rod spring 6A extending in the optical axis direction connects with the corrected portion 1D. Because the support actuators 5 mainly support the load of the main reflector 1, the support pillar 5A is columnar with a diameter about 10 times that of the rod spring 6A.

[0034] The six shape correction actuators 6 arranged second farthest from the center of the mirror surface extend in the radial direction. Of the six shape correction actuators 6 arranged farthest from the center of the mirror surface, three shape correction actuators 6 arranged at angular positions where no support actuators 5 are arranged also extend in the radial direction. Of the six shape correction actuators 6 arranged at the farthest positions, three shape correction actuators 6 arranged at angular positions where support actuators 5 are arranged extend in a direction that forms an angle of 60 degrees with respect to the radial direction. The remaining three support actuators 5 extend in a direction that forms an angle of 34 degrees with respect to the radial direction. Because space becomes narrower closer to the center of the mirror surface, the six shape correction actuators 6 closest to the center of the mirror surface extend in a direction that forms an angle of 30 degrees with respect to the radial direction so as not to interfere with each other.

[0035] The operating principles of the support actuators and shape correction actuators 6 will be described with reference to Figures 11 and 12. Figure 11 is a vertical cross-sectional schematic diagram of a reflecting mirror device. Figure 11 is a cross-sectional diagram along the line BB shown in Figure 7. The BB cross-section is a cross-section including the optical axis LX of the main reflecting mirror. Figure 12 is a cross-sectional schematic diagram showing actuators provided in a reflecting mirror device according to embodiment 1. Note that the support actuators shown in Figures 11 and 12 have a different structure from the support actuators 5 used in reflecting mirror device 1. The support actuators shown in Figure 11 are denoted by the reference numeral 7. Figure 11 shows the shape correction actuators 6 and support actuators 7 arranged at the innermost and middle positions with respect to the center of the mirror surface. Figure 12 shows the shape correction actuators 6 and support actuators 7 arranged at the outermost positions.

[0036] First, the operating principle of the shape correction actuator 6 will be described. The shape correction actuator 6 mainly comprises a rod spring 6A, a link member 6B, a support 6C, a rotation shaft 6D, a voice coil motor 8, a brake 9, and a displacement meter 10. One end of the rod spring 6A is connected to the area to be corrected 1D, and it pushes and pulls the area to be corrected 1D in the optical axis direction. The voice coil motor 8 generates a driving force that moves the rod spring 6A. The link member 6B, the support 6C, and the rotation shaft 6D transmit the driving force generated by the voice coil motor 8 to the rod spring 6A. The link member 6B, the support 6C, and the rotation shaft 6D form a lever. The brake 9 prevents the link member 6B from rotating around the rotation shaft 6D. The displacement meter 10 is provided on the surface of the rear disk member 2 facing the main reflector 1. The displacement meter 10 measures the distance between the rear disk member 2 and the main reflector 1 near the area to be corrected 1D. The displacement meter 10 is, for example, an eddy current distance sensor.

[0037] The other end of the rod spring 6A is attached to a link member 6B. The point on the link member 6B where the other end of the rod spring 6A is attached is called the point of application 6E. A support 6C is provided on the back surface of the rear disk member 2. A rotation axis 6D is provided near the lower end of the support 6C, perpendicular to the direction in which the link member 6B extends. The link member 6B is rotatable around the rotation axis 6D. The rotation axis 6D is the fulcrum of the link member 6B, functioning as a lever. The rod spring 6A absorbs the difference in thermal deformation between the rear structure frame 3 and the rear disk member 2. The rigidity of the rod spring 6A allows it to rotate in the radial direction but is rigid in the tangential direction. The rod spring 6A is attached to the correction location 1D and the link member 6B so that it can rotate in the radial direction. The rod spring 6A is a rod-shaped member with one end connected to the shape correction location and the other end attached to the link member.

[0038] The voice coil motor 8 has a plate-shaped permanent magnet 8A and an electromagnet 8B arranged to sandwich the permanent magnet 8A. The voice coil motor 8 changes the force acting between the permanent magnet 8A and the electromagnet 8B by changing the current flowing through the electromagnet 8B. The center of the plate-shaped permanent magnet 8A is called the force point 6F. The distance between the force point 6F and the rotation axis 6D is called the variable L. Ａ The distance between the point of action 6E and the rotation axis 6D is expressed as a variable L Ｂ In the shape correction actuator 6, L Ａ ≒ 2 * L Ｂ It is. Ａ >L Ｂ The rod spring 6A can move up and down within a range of about ±1 mm. The voice coil motor 8 moves the link member 6B up and down within a range of ±several mm.

[0039] The voice coil motor 8 is a link drive unit that generates a force that moves the link member 6B in the optical axis direction. The voice coil motor 8 is provided at a position on the link member 6B opposite the location where the rod spring 6A is attached to the rotation axis 6D, which serves as the fulcrum, such that the distance between the voice coil motor 8 and the rotation axis 6D is greater than the distance between the location where the rod spring 6A is attached and the rotation axis 6D. A motor or mechanism of a type other than a voice coil motor may be used as the link drive unit. The link drive unit may be any type that applies an electromagnetic force to the link member 6B without coming into contact with the link member 6B.

[0040] 12 shows that the permanent magnet 8A is provided on the side of the link member 6B, and the electromagnet 8B is provided on the side of the rear disk member 2. It is also possible to provide the permanent magnet 8A on the side of the rear disk member 2, and the electromagnet 8B on the side of the link member 6B.

[0041] The voice coil motor 8 changes the force acting on the force point 6F, thereby moving the force point 6F in the optical axis direction. When the force point 6F moves in the optical axis direction, the link member 6B rotates around the rotation axis 6D, causing the action point 6E and therefore the rod spring 6A to move in the optical axis direction. The direction in which the rod spring 6A moves is opposite to the direction in which the force point 6F moves. In other words, the voice coil motor 8 moves the rod spring 6A in the optical axis direction, and the rod spring 6A pushes and pulls the area to be corrected 1D of the main reflecting mirror 1. The shape correction actuator 6 amplifies the minute driving force of the voice coil motor 8 and reduces the displacement, generating a driving force and displacement that enable shape correction of the mirror surface 1A.

[0042] The brake 9 is provided on the link member 6B at a position on the same side of the rotary shaft 6D as the voice coil motor 8 but farther from the rotary shaft 6D than the voice coil motor 8. The brake 9 includes a brake plate 9A, a brake pad 9B, a spring 9C, and an electromagnet 9D. FIG. 15 illustrates the brake plate 9A and the electromagnet 9D. The brake pad 9B and the spring 9C are not shown. The brake plate 9A is provided on the link member 6B at a position on the force point 6F side of the link member 6B farther from the rotary shaft 6D than the force point 6F. The brake pad 9B contacts the brake plate 9A and prevents the brake plate 9A and the link member 6B from moving relative to the rear disk member 2 by friction. The spring 9C is biased to press the brake pad 9B against the brake plate 9A. The electromagnet 9D attracts the brake pad 9B during operation to prevent the brake pad 9B from coming into contact with the brake plate 9A. When no power is supplied to the brake 9, the brake pad 9B is in contact with the brake plate 9A, and the brake plate 9A and therefore the link member 6B do not move. The state in which the brake 9 prevents the link member 6B from moving relative to the back disc member 2 is called a locked state. The state in which the brake plate 9A and the link member 6B can move relative to the back disc member 2 is called an unlocked state. The brake 9 maintains the unlocked state when no power is supplied.

[0043] The support actuator 7 is a ball screw type actuator. The support actuator 7 has a fixed part 7A and a movable part 7B. The fixed part 7A is fixed to the rear structure frame 3. The movable part 7B can move in the optical axis direction relative to the fixed part 7A. A mechanism for moving the movable part 7B is housed inside the fixed part 7A. The interior of the fixed part 7A is not shown. A stepping motor 7C, a threaded rod 7D, a gear mechanism 7E, and a nut 7F are housed inside the fixed part 7A. These constitute a mechanism for moving the movable part 7B relative to the fixed part 7A. The threaded rod 7D extends in the optical axis direction inside the fixed part 7A and is rotatably held by the fixed part 7A. The threaded rod 7D is a rod with a circular cross section and a male thread on the side. The nut 7F has a through hole with a female thread on the inner surface that meshes with the threaded rod 7E. The nut 7F does not rotate relative to the fixed part 7. When the threaded rod 7D rotates, the nut 7F moves along the threaded rod 7D. The nut 7F is connected to the movable part 7B. When the nut 7F moves, the movable part 7B also moves. The threaded rod 7D has a male thread on the side that engages with the movable part 7B, and when it rotates, it moves the movable part 7B relative to the fixed part 7A.

[0044] The threaded rod 7D may be connected to the movable part 7B, and when the threaded rod 7D rotates, the threaded rod 7D and the movable part 7B may move. A stepping motor, a threaded rod, a gear mechanism, and a nut may be provided in the movable part.

[0045] The stepping motor 7C and gear mechanism 7E rotate the threaded rod 7D. The gear mechanism 7E transmits the rotation of the stepping motor 7C to the threaded rod 7D, causing it to rotate. The stepping motor 7C is a movable part drive unit that generates a driving force to move the movable part 7B. The stepping motor 7C generates a driving force to rotate the threaded rod 7D. The gear mechanism 7E transmits the rotation of the stepping motor 7C to the threaded rod 7D so that the threaded rod 7D rotates. The gear ratio of the gear mechanism 7E is sufficiently large. Therefore, the threaded rod 7D rotates with a small driving force of the stepping motor 7C. Furthermore, when power is no longer supplied to the support actuator 7, even if a force acting to move the movable part 7B in the optical axis direction acts, the threaded rod 7D does not rotate, and the position of the movable part 7B can be maintained even in the event of a power outage. Because the support actuator is a ball-screw actuator, it can generate a position-holding force greater than that achieved by a brake.

[0046] The upper part of the movable part 7B has a shape similar to that of the support column 5A. The upper part of the movable part 7B is rotatably connected to the supported part 1C via a spherical bearing 1E with two degrees of freedom of rotation. The spherical bearing 1E allows the movable part 7B to hold the main reflecting mirror 1 as a rigid body. The spherical bearing 1E absorbs moment reaction forces at the point where the movable part 7B supports the supported part 1C. This prevents harmful deformation from being transmitted to the mirror surface 1A. The movable part 7B also has a thermal deformation relief spring 7G (shown in FIG. 12). The thermal deformation relief spring 7G is provided to absorb the difference in thermal deformation between the rear structure frame 3 and the rear disc member 2.

[0047] In the support actuator 7, the movable part 7B moves in the optical axis direction in accordance with the amount of rotation of the stepping motor 7C. Since the movable part 7B is connected to the supported part 1C, when the movable part 7B moves, the movable part 7B pushes or pulls the supported part 1C.

[0048] The structure of the shape correction actuator 6 will be described with reference to Figures 13 to 16. Figure 13 is a side view of the reflecting mirror device 50. Figure 14 is an enlarged side view of the reflecting mirror device 50. Figure 14 is an enlarged view of area F shown in Figure 13. Figures 13 and 14 are side views viewed from the line of sight C shown in Figure 8. Note that Figures 13 and 14 do not show the displacement meter 10. Figure 15 is a bottom view of the reflecting mirror device 50. Figure 16 is a horizontal cross-sectional view of the reflecting mirror device 50. Figure 16 is a cross-sectional view seen from above at cross section GG shown in Figure 14. The shape correction actuator 6 shown in Figures 14 to 16 is arranged in the lowest position in Figure 8 on the outermost arrangement circle.

[0049] The shape correction actuator 6 mainly includes a rod spring 6A, a link member 6B, a rod spring mounting portion 6G, a pivot member 11, a voice coil motor 8, and a brake 9. The pivot member 11 functions as a support and fulcrum. When viewed from the side, the upper surface of the link member 6B is recessed where the pivot member 11 connects. The lower surface of the link member 6B is inclined so that it rises toward the ends on both sides of the connecting portion. The pivot member 11 connects to the link member 6B so that the front of the pivot member 11, which appears as two intersecting plates, is perpendicular to the direction in which the link member 6B extends. When viewed from the bottom, the link member 6B has a horizontally elongated, approximately rectangular shape, tapering toward the end where the rod spring 6A connects. A cylindrical rod spring mounting portion 6G is provided at the tapered end of the link member 6B. The rod spring 6A is attached to the center of the upper surface of the rod spring mounting portion 6G. The link member 6B and the rod spring mounting portion 6G are integrally formed and have a thin, hollow structure.

[0050] The voice coil motor 8 is cylindrical. The internal structure of the voice coil motor 8 is not shown. The voice coil motor 8 has a permanent magnet 8A, an electromagnet 8B, a connecting portion 8C, and a weight 8D. The permanent magnet 8A of the voice coil motor 8 is connected to the back surface of the rear disk member 2 by two connecting portions 8C. The voice coil motor 8, except for the permanent magnet 8A and the connecting portion 8C, is attached to the link member 6B. Inside the voice coil motor 8, the electromagnet 8B sandwiches the permanent magnet 8A. The voice coil motor 8 generates a driving force that moves the link member 6B up and down by changing the strength of the magnetic field generated by the electromagnet 8B. The weight 8D is of such a weight that the moments acting due to gravity on both sides of the rotation shaft 6D are approximately equal. The weight 8D is provided on the lower side inside the voice coil motor 8. "The moments are approximately equal" means that the difference between the moments due to gravity acting on both sides of the rotation shaft 6D is equal to or less than a predetermined upper moment limit. The moment due to gravity on the side where the rod spring 6A is present includes the moment due to the load of the main reflector 1 borne by the rod spring 6A at the correction point 1D. The upper limit of the moment is set to a necessary and sufficiently small value.

[0051] The brake 9 has a structure in which an electromagnet 9D sandwiches a brake plate 9A that is parallel to the direction in which the link member 6B extends and the optical axis direction.

[0052] The structure of the pivot member 11 will be described with reference to Figure 17. Figure 17 is a diagram illustrating the structure of the pivot member 11 of the shape adjustment actuator 6 of the reflecting mirror device 50. Figure 17(A) is a front view of the pivot member 11. Figure 17(B) is a right side view. Figure 17(C) is a plan view. Figure 17(D) is a horizontal cross-sectional view at cross section HH shown in Figures 17(A) and (B). Figure 17(E) is a side view seen from the line of sight J shown in Figure 17(C).

[0053] The pivot member 11 has a fixed plate 11A, a movable plate 11B, a first swash plate 11C, a second swash plate 11D, and a third swash plate 11E. The fixed plate 11A is fixed to the rear surface of the rear disk member 2. The movable plate 11B is connected to the upper surface of the link member 6B. The fixed plate 11A and the movable plate 11B are square plates of the same size and thickness. When no force is applied to the pivot member 11, the fixed plate 11A and the movable plate 11B are parallel to each other.

[0054] The first swash plate 11C and the third swash plate 11E are plates that connect the right end of the fixed plate 11A in FIG. 17A to the left end of the movable plate 11B in FIG. 17A. The second swash plate 11D is a plate that connects the left end of the fixed plate 11A in FIG. 17A to the right end of the movable plate 11B in FIG. 17A. The first swash plate 11C, the second swash plate 11D, and the third swash plate 11E have the same thickness.

[0055] To explain the structure of the pivot member 11, a UVW Cartesian coordinate system is defined. The plane parallel to the fixed plate 11A and the movable plate 11B is defined as the UV plane, and the direction perpendicular to the fixed plate 11A and the movable plate 11B is defined as the W axis. The U axis and V axis are defined parallel to the sides of the square fixed plate 11A and the movable plate 11B. The V axis is defined in the direction in which the sides of the first swash plate 11C, the second swash plate 11D, and the third swash plate 11E are visible. The U axis is perpendicular to the V axis in the UV plane. The direction from bottom to top in Figure 17(A) is defined as the positive direction of the W axis. The direction from left to right in Figure 17(C) is defined as the positive direction of the U axis, and the direction from bottom to top is defined as the positive direction of the V axis.

[0056] As shown in Figure 17(A), the first swash plate 11C and the second swash plate 11D intersect when viewed from the front. As shown in Figure 17(B), when viewed from the side, the first swash plate 11C connects the left ends of the fixed plate 11A and the movable plate 11B. The second swash plate 11D connects the center of the fixed plate 11A and the movable plate 11B. The third swash plate 11E connects the right ends of the fixed plate 11A and the movable plate 11B. The first swash plate 11C and the third swash plate 11E have the same width, and the width of the second swash plate 11D is twice the width of the first swash plate 11C. As shown in Figure 17(B), the width of the space between the first swash plate 11C, the second swash plate 11D, and the third swash plate 11E when viewed from the side is very small. Therefore, when the pivot member 11 is viewed from the side, it appears that one of the first swash plate 11C, the second swash plate 11D, and the third swash plate 11E is present between the fixed plate 11A and the movable plate 11B.

[0057] The pivot member 11 has a rotation axis 11F parallel to the V-axis at the position where the first swash plate 11C and the second swash plate 11D intersect when viewed from the front. When the voice coil motor 8 applies force to the link member 6B, the pivot member 11 rotates about the rotation axis 11F, causing the movable plate 11B to rotate relative to the fixed plate 11A. This is because the first swash plate 11C, the third swash plate 11E, and the second swash plate 11D, which intersect when viewed from the front, are each bent as a cantilever plate, with the end connected to the fixed plate 11A fixed and the end connected to the movable plate 11B movable.

[0058] Since the pivot member 11 is connected to a recessed portion on the top surface of the link member 6B, the rotation axis 11F is located at approximately the same height as the connection point between the link member 6B and the rod spring 6A. The rotation axis 11F of the pivot member 11 is the rotation axis 6D of the shape correction actuator 6.

[0059] The structure of the support actuator 5 will be described with reference to Figures 18 to 20. Figure 18 is another side view of the reflecting mirror device 50. Figure 19 is another enlarged side view of the reflecting mirror device 50. Figure 20 is a cutaway view showing a portion of the interior of the support actuator 5 in Figure 19. Figures 18 to 20 are side views of the reflecting mirror device 50 as seen from the line of sight D shown in Figure 8. Figure 19 is an enlarged side view of region K shown in Figure 18. Figure 20 further enlarges the support actuator 5 portion of Figure 19. In Figures 19 and 20, the rear disk member 2 is shown as a cross-sectional view taken along the E-E cross section shown in Figure 8. In Figure 20, the upper part of the movable portion 5C of the support actuator 5 is shown cut away. The support actuator 5 shown in Figures 19 and 20 is disposed at the bottom left in Figure 8.

[0060] The support actuator 5 has a support column 5A, a fixed portion 5B (shown in FIG. 20), a movable portion 5C, a spring 5D, a link member 5E, a fulcrum pivot member 12, a connecting pivot member 13, and a brake 14. Because the mechanism for moving the movable portion 5C is a ball screw mechanism, the support actuator 5 is a ball screw type actuator. The support actuator 5 uses a lever to increase the force acting on the movable portion 5C and have it act through the support column 5A. The support column 5A is a support rod-shaped member connected to the supported location 1C. The fixed portion 5B is disk-shaped. The fixed portion 5B is fixed to the back surface of the rear disk member 2. The movable portion 5C can move in the optical axis direction relative to the fixed portion 5B. The movable portion 5C is connected to the surface of the link member 5E that is farther from the rear disk member 2. The ball screw mechanism for moving the movable portion 5C passes through a space provided in the link member 5E, and one end of the ball screw mechanism contacts the fixed portion 5B. The fulcrum pivot member 12 is a pivot member that serves as a fulcrum for the support actuator 5 as a lever. The fulcrum pivot member 12 has a rotation axis 12F. The rotation axis 12F is a support fulcrum that allows the link member 5E to rotate around it. The connection pivot member 13 is a pivot member that connects the link member 5E and the support column 5A. The brake 14 prevents the link member 5E from moving relative to the back disk member 2.

[0061] A cylindrical internal space exists above the portion of the link member 5E where the movable portion 5C is connected. The cylindrical internal space of the link member 5E is connected to the internal space of the movable portion 5C. Part of the ball screw mechanism that moves the movable portion 5C exists in the cylindrical internal space of the link member 5E. An annular protrusion 5F that expands the cylindrical space upward in the figure is provided on the surface of the rear disc member 2 of the link member 5E. A spring 5D is provided between the rear disc member 2 and the link member 5E so that the fixed portion 5B and the annular protrusion 5F enter its interior. The spring 5D pushes the link member 5E in a direction away from the rear disc member 2.

[0062] As shown in FIG. 20 , the movable portion 5C includes a nut storage portion 5G, a nut 5H, a threaded rod 5J, a tip disk 5K, a ball 5L, a motor storage portion 5M, a stepping motor 5N (not shown), and a gear mechanism 5P (not shown). The nut storage portion 5G is a member attached to the link member 5E. The nut storage portion 5G is a cylindrical member with a bottom surface and a flange, open on one side. The open end of the nut storage portion 5G is attached to the link member 5E. The nut storage portion 5G has a cylindrical space that communicates with the internal space of the link member 5E. The nut storage portion 5G stores the nut 5H and the threaded rod 5J. The nut 5H is fixed to the bottom surface of the nut storage portion 5G.

[0063] The tip disk 5K is a disk-shaped plate attached to the tip of the threaded rod 5J. The ball 5N is a sphere. The ball 5N is located between the tip disk 5K and the fixed portion 5B and engages the tip disk 5K with the fixed portion 5B so that the angle between the tip disk 5K and the fixed portion 5B can be changed. A recess with a shape that fits the spherical surface of the ball 5N is provided at the center of the tip disk 5K and the fixed portion 5B when viewed from the optical axis direction. The ball 5N fits into the recesses provided in the tip disk 5K and the fixed portion 5B. The motor housing 5M houses the stepping motor 5N and the gear mechanism 5P. The motor housing 5M is shaped like a rectangular pillar. The stepping motor 5N and the gear mechanism 5P rotate the threaded rod 5J and the tip disk 5K.

[0064] The threaded rod 5J is a rod with a circular cross section and a male thread on its side. The nut 5H has a through hole with a female thread on its inner surface that meshes with the threaded rod 5J. When the threaded rod 5J rotates, the threaded rod 5J moves relative to the nut 5H. As the threaded rod 5J moves, the length of the threaded rod 5J extending upward from the nut storage section 5G changes. As the length of the threaded rod 5J extending upward from the nut storage section 5G changes, the distance between the tip disk 5K and the bottom surface of the nut storage section 5G changes. A motor storage section 5M is attached to the underside of the nut storage section 5G. Therefore, when the threaded rod 5J rotates, the entire movable section 5C rotates and moves around the rotation axis 12F. Note that the tip disk 5K and the fixed section 5B are connected via a ball 5N, which is a sphere, so the entire movable section 5C can rotate around the rotation axis 12F. The threaded rod 5J has a male thread on its side, and when it rotates, it moves the movable section 5C relative to the fixed section 5B. The threaded rod 5J is included in the support actuator 5, and the threaded rod 5J engages with the movable part 5C.

[0065] The threaded rod 5J passes through an opening provided on the bottom surface of the nut storage section 5G. The lower portion of the threaded rod 5J is located inside the motor storage section 5M. Inside the motor storage section 5M, a stepping motor 5N and a gear mechanism 5P rotate the threaded rod 5J. The gear mechanism 5P transmits the rotation of the stepping motor 5N to the threaded rod 5J, causing it to rotate. The stepping motor 5N is a movable part drive section that generates a driving force to move the movable part 5C. The stepping motor 5N generates a driving force to rotate the threaded rod 5J.

[0066] The link member 5E is connected to the movable part 5C on one side of the fulcrum pivot member 12. The point of the link member 5E where it connects to the movable part 5C is called the force point 5Q. The link member 5E is connected to the support column 5A on the other side. The point of the link member 5E where it connects to the support column 5A is called the application point 5R. The link member 5E is a support link member to which the support column 5A is connected and which is rotatable around the rotation axis 12F. The force point 5Q is the point where the driving force generated by the stepping motor 5N acts. In the link member 5E, the force point 5Q is located on the opposite side of the link member 5E with respect to the rotation axis 12F, at a point where the distance from the rotation axis 12F is greater than the distance between the application point 5R and the rotation axis 12F.

[0067] The fulcrum pivot member 12 is provided between the location where the movable portion 5C is connected to the upper surface of the link member 5E and the location where the support column 5A is connected. The fulcrum pivot member 12 is connected to the link member 5E so that the rotation axis 12F is perpendicular to the direction in which the link member 5E extends. The fulcrum pivot member 12 is a pivot member that functions as a fulcrum for rotating the link member 5E and as a column on which the fulcrum is provided. The rotation axis 12F of the fulcrum pivot member 12 is the rotation axis 5S of the support actuator 5. The fulcrum pivot member 12 is a support column provided on the back surface of the back disk member 2 on which the rotation axis 12F is provided.

[0068] The connecting pivot member 13 is a pivot member that connects the link member 5E and the support column 5A. The connecting pivot member 13 is provided to prevent the reaction force caused by the tilt of the link member 5E from being transmitted to the supported location 1C via the support column 5A when the link member 5E tilts. The connecting pivot member 13 connects to the link member 5E so that the rotation axis 13F is perpendicular to the direction in which the link member 5E extends. Because the support column 5A connects to the link member 5E via the connecting pivot member 13, the support column 5A moves only in the optical axis direction. The connecting pivot member 13 also absorbs the difference in thermal deformation between the rear structure frame 3 and the rear disk member 2, preventing unnecessary force from being transmitted to the supported location 1C.

[0069] The link member 5E has a thin, hollow structure. The fulcrum pivot member 12 and the connection pivot member 13 are made of as thin a plate material as possible within the range that provides the required strength.

[0070] The top surface of the link member 5E is lower on the right side in the figure. The fulcrum pivot member 12 and the connecting pivot member 13 are connected to the lower portion of the top surface of the link member 5E. This allows the rotation axis 12F of the fulcrum pivot member 12 and the rotation axis 13F of the connecting pivot member 13 to be positioned at the same position as the top surface of the link member 5E. In Figure 19, the force point 5Q and the point of action 5R of the link member 5E, which serves as a lever, are drawn at the same height as the rotation axis 5S, which serves as the fulcrum. The point of action 5R is at the same position as the rotation axis 13F.

[0071] In the support actuator 5, the movable part 5C moves in the optical axis direction according to the amount of rotation of the stepping motor 5F. The movable part 5C is connected to the supported part 1C via a link member 5E and a support pillar 5A. Therefore, when the movable part 5C moves, the support pillar 5A pushes or pulls the supported part 1C.

[0072] In the support actuator 5, the distance between the force point 5Q and the rotation axis 12F is defined as a variable L Ｃ The distance between the point of action 5R and the rotation axis 12F is expressed as a variable L Ｄ In the support actuator 5, L Ｃ ≒ 2 * L Ｄ It is. Ｃ >L Ｄ That's fine.

[0073] The brake 14 is located farther from the fulcrum pivot member 12 than the movable portion 5C. The brake 14 has a structure similar to that of the brake 9. Although not shown, the brake 14 includes a brake plate 14A, a brake pad 14B, a spring 14C, and an electromagnet 14D. The brake plate 14A is located on the opposite side of the movable portion 5C from where the link member 5E is connected, in the direction in which the link member 5E extends. The brake pad 14B contacts the brake plate 14A and prevents the brake plate 14A from moving by friction. The spring 14C is biased to move the brake pad 14B away from the brake plate 9A. When activated, the electromagnet 14D attracts the brake pad 14B, bringing the brake pad 14B into contact with the brake plate 14A. When power is not supplied to the brake 14, the brake pad 14B is not in contact with the brake plate 14C, allowing the brake plate 14C and the link member 5E to move. The state in which the brake 14 prevents the link member 5E from moving is called a locked state, and the state in which the link member 5E is movable is called an unlocked state.

[0074] The brake 14 is a support brake that prevents the link member 5E from rotating. The brake 14 is provided on the same side as the stepping motor 5N with respect to the rotation axis 12F of the link member 5E, and prevents the link member 5E from moving relative to the back disk member 2.

[0075] When power is not supplied to the support actuator 5, the brake 14 maintains an unlocked state in which the link member 5E is movable relative to the back disk member 2. When power is not supplied to the support actuator 5, the support actuator 5 prevents the link member 5E from rotating with a force greater than that of the brake 14. Therefore, when power is not supplied to the support actuator 5, the holding force of the brake 14 is not necessary, and in order to reduce power consumption, the brake 14 is in an unlocked state when power is not supplied.

[0076] The reflecting mirror device 50 has three support actuators 5 and eighteen shape correction actuators 6 arranged as shown in FIG. 10. The reflecting mirror 50 can correct deformations of the mirror surface 1 in the Zenikel modes j = 1 to 16, which are enclosed by dashed lines in FIG. 21. FIG. 21 shows the Zenikel modes of the mirror surface. Zenikel modes are deformation modes of the mirror surface expressed by Zenikel polynomials. Zenikel polynomials are orthogonal polynomials defined on and within the circumference of a unit circle. Zenikel polynomials are commonly used in optics to analytically treat axisymmetric optical aberrations based on diffraction theory. In FIG. 21, the darker the gray, the greater the amount of convex or concave deformation. Concave deformations are indicated by white circles, white-lined circles, or white arcs in the gray areas.

[0077] When the point P = (x, y) on the mirror surface 1A, which is represented by a unit circle, is expressed in polar coordinates (r, θ), the Zenikel polynomial Φ n,m (r, θ) is expressed by the following equations (1) to (3). θ is the angle between the line segment OP and the X-axis. n is a non-negative integer. m is an integer that satisfies |m|≦n.

[0078]

[0079] The coefficient R(s) determined by the sigma subscript s used in equations (1) to (3) is expressed by equation (4) below.

[0080]

[0081] Referring to Figure 22, the configuration of a reflecting mirror surface adjustment system 70 that adjusts the shape of the mirror surface 1A of the main reflecting mirror 1 of the reflecting mirror device 50 will be described. The reflecting mirror surface adjustment system 70 includes a reflecting mirror device 50, a wavefront sensor 71, a mirror surface shape adjustment device 72, and a network 73. The wavefront sensor 71 is installed in front of the mirror surface 1A in the optical axis direction. The wavefront sensor 71 measures the shape of the mirror surface 1A. The wavefront sensor 71 is, for example, a Shack-Hartmann wavefront sensor. The mirror surface shape adjustment device 72 receives data (mirror surface shape data) representing the shape of the mirror surface 1A measured by the wavefront sensor 71, and controls the support actuators 5 and shape correction actuators 6 so that the shape of the mirror surface 1A becomes the intended shape. Each of the support actuators 5 and shape correction actuators 6 will be referred to as an actuator.

[0082] The network 73 enables the reflecting mirror device 50, the wavefront sensor 71, and the mirror surface shape adjustment device 72 to communicate with each other. The network 73 is a local area network (LAN). It is also possible to connect the wavefront sensor 71 and the mirror surface shape adjustment device 72 with a dedicated signal line without using a network. It is also possible to connect each actuator and the mirror surface shape adjustment device 72 with a dedicated signal line.

[0083] The mirror surface shape adjustment device 72 has a data storage unit 80, a communication unit 74, a mode decomposition unit 75, a displacement amount calculation unit 76, and an actuator control unit 77. The data storage unit 80 stores data necessary for control. The communication unit 74 communicates with the reflecting mirror device 50 and the wavefront sensor 71. The mode decomposition unit 75 decomposes the mirror surface shape data into Zenikel modes. The displacement amount calculation unit 76 calculates the displacement amount of each actuator to cancel out the deformation of the mirror surface 1A, which is represented by the weighted sum of the decomposed Zenikel modes. The actuator control unit 77 controls each actuator according to the calculated displacement amount.

[0084] The data storage unit 80 stores ideal mirror surface data 81, mirror surface shape data 82, differential shape data 83, Zenikel mode data 84, modal decomposition result 85, actuator data 86, and actuator operation amount 87. The ideal mirror surface data 81 is data that stores the desired shape that the mirror surface 1A should assume. The ideal mirror surface data 81 is pre-stored. The mirror surface shape data 82 is mirror surface shape data measured by the wavefront sensor 71. The differential shape data 83 is data that indicates how the mirror surface shape data 82 differs from the ideal mirror surface data 81. The Zenikel mode data 84 is data that indicates the shape of the mirror surface 1A using the Zenikel polynomials of each mode. The Zenikel mode data 84 also includes data on the displacement amount of each actuator to cancel out the deformation of the mirror surface 1A due to each mode when only a unit amount of each mode exists. The modal decomposition result 85 is data that indicates the amount of each Zenikel mode included in the differential shape data 83. The differential shape data 83 and the mode decomposition result 85 are calculated by the mode decomposition unit 75 .

[0085] The actuator data 8 is data that stores the installation position of each actuator, a coefficient for amplifying the force of the lever, parameters used for control, etc. The parameters used for control include a time constant and a threshold value. The actuator operation amount 87 is data that represents the displacement amount by which each actuator should be operated in order to make the shape of the mirror surface 1A as close as possible to the ideal mirror surface data 81. The actuator operation amount 87 is calculated by the displacement amount calculation unit 76 with reference to the Zenikel mode data 84, the mode decomposition result 85, and the actuator data 86. The actuator control unit 77 controls each actuator with reference to the actuator operation amount 87 and the actuator data 8.

[0086] The mode decomposition unit 75 calculates weighting coefficients for the Zenikel modes of each order so that the shape of the mirror surface 1A represented by the differential shape data 83 can be obtained by weighting and superimposing the Zenikel modes of each order. The mode decomposition unit 75 calculates weighting coefficients for Zenikel modes up to a predetermined order of the target (abbreviated as the suppression target) for which deformation is to be reduced (suppressed). The weighting coefficients for each Zenikel mode of the suppression target are the mode decomposition result 85.

[0087] The displacement amount calculation unit 76 calculates the actuator operation amount 87 by multiplying the displacement amount of each actuator for canceling each Zenikel mode by the mode decomposition result 85 and adding the results.

[0088] The actuator control unit 77 controls the actuator operation amount 87 so that the final displacement amount is appropriate, taking into consideration the response characteristics of the main reflector 1 when a force is applied, the response characteristics of each actuator, etc. The actuator control unit 77 controls each actuator using an appropriate control method, such as PID control, optimal control, or another control method.

[0089] The actuator control unit 77 controls each actuator so that it does not move too much, also referring to the displacement amount measured by the displacement meter 10. If the displacement amount exceeds a threshold, the actuator control unit 77 has a function to stop control.

[0090] The mirror surface shape adjustment device 72 receives mirror surface shape data 81 and controls the voice coil motor 8 and stepping motor 5N so that the mirror surface 1A takes a shape that minimizes the difference from the ideal mirror surface data 81.

[0091] The operation will be described below. Figure 23 is a flowchart illustrating the procedure for launching a telescope having a reflector apparatus according to embodiment 1 into space and using it for observation. In step S01, an artificial satellite carrying a telescope including a reflector apparatus 50 is loaded onto a rocket. In step S02, in the reflector apparatus 50, the brake 14 of the support actuator 5 is energized to lock it, and the brake 9 of the shape correction actuator 6 is de-energized to lock it. In step S03, the rocket is launched. In step S04, the artificial satellite is placed into a predetermined orbit.

[0092] In step S05, the reflecting mirror device 50 is placed in a reaction force-free state. In the reaction force-free state, the displacement amounts of the three support actuators 5 are the same, the brakes 14 of the support actuators 5 are not energized and are in an unlocked state, the brakes 9 of the shape correction actuators 6 are energized and are in an unlocked state, and the driving force of the voice coil motors 8 of the shape correction actuators 6 is set to zero. In step S06, the wavefront sensor 71 measures the shape of the mirror surface 1A and generates mirror surface shape data.

[0093] In step S07, the mode decomposition unit 75 generates differential shape data 83, which is the difference between the mirror surface shape data 82 and the ideal mirror surface data 81. In step S08, the mode decomposition unit 75 refers to the Zenikel mode data 84 and calculates weighting coefficients for multiple Zenikel modes that are weighted and superimposed to become as close as possible to the differential shape data 83. The calculated weighting coefficients for the Zenikel modes to be suppressed are the mode decomposition result 85.

[0094] In step S09, the displacement amount calculation unit 76 calculates the actuator operation amount 87. The actuator operation amount 87 is the amount of displacement of the support actuators 5 and the shape correction actuators 6 that cancels out the deformation of the mirror surface 1A represented by the mode decomposition result 85.

[0095] In step S10, the actuator control unit 77 controls each actuator so that the support actuator 5 and the shape correction actuator 6 take the amount of displacement represented by the actuator operation amount 87. The actuator control unit 77 performs appropriate control taking into consideration the response characteristics.

[0096] In step S11, the shape correction actuator 6 is energized to unlock the brake 9, and the support actuator 5 is deenergized to lock the brake 14. In step S12, the telescope starts observation.

[0097] The reflector device 50 can also be used on Earth. The procedure for installing an optical telescope having the reflector device 50 on Earth and using it for observation will be described with reference to Figure 24. Figure 24 is a flowchart for explaining the procedure for installing an optical telescope having the reflector device according to the first embodiment on Earth and using it for observation.

[0098] Regarding Figure 24, the differences from Figure 23 will be explained below. Steps S01 to S03 are not included. Instead of S04, in step S04A, an optical telescope including reflector device 50 is installed on the Earth. The processing from S05 onwards is the same.

[0099] Reflector device 50 is lighter than conventional reflector devices that have actuators that actively control the mirror surface shape. Lighter than conventional reflector devices means that when a reflector of the same size, shape, and weight is used to control the shape with the same number of actuators, reflector device 50 is lighter than the conventional reflector device. Conventional reflector devices are reflector devices that use actuators that do not use levers.

[0100] The force that each actuator must apply to the main reflector 1 to change the shape of the mirror surface 1A is the same in both the reflector device 50 and conventional reflector devices. In the reflector device 50, each actuator uses a lever, so the driving force that the voice coil motor 8 must generate can be smaller than when no lever is used. As a result, the weight of the voice coil motor 8 can be lighter than the weight of the motor used in conventional reflector devices. Because the motor is lightweight and has a small driving force, the sturdiness that each actuator needs to have does not need to be as strong as conventional ones. The weight of the actuator as a whole can be reduced. The reflector device 50 also requires link members for the levers. The link members only need to be able to handle small driving forces, so they can be lightweight. The reflector device 50 can be lighter than conventional devices, even when the weight of the link members and other components is included.

[0101] In the reflector device 50, each actuator has a brake, which can be activated to lock each actuator. Furthermore, because the support actuators 5 are ball-screw type actuators, even if an external force is applied with the brakes 14 unlocked, the screws do not rotate and the supporting position can be maintained. The load applied to the main reflector 1 during launch is mainly borne by the support actuators 5. Since the brakes 9 are activated on the shape correction actuators 6, no force is generated to push or pull the area to be corrected 1D. When launching by rocket, the brakes 9 of each shape correction actuator 6 are activated to lock each shape correction actuator 6, thereby preventing damage to the reflector device 50 due to the impact during launch.

[0102] In the reflecting mirror device 50, after each actuator has completed correcting the shape of the mirror surface 1A, the power supply to the shape-correcting actuator 6 is stopped. The brake 9 of the shape-correcting actuator 6 operates, allowing each shape-correcting actuator 6 to maintain the state in which it has corrected the shape of the mirror surface 1A. When the reflecting mirror device 50 is in use, power is not supplied to the voice coil motor 8 of each shape-correcting actuator 6. Therefore, the reflecting mirror device 50 can maintain the shape of the mirror surface 1A without consuming power.

[0103] If the motor needs to be constantly operated to maintain the shape of the mirror surface 1A, the motor may generate heat, which may cause deformation of the mirror surface 1A. The reflector device 50 does not consume power to maintain the shape of the mirror surface 1A during observation, which reduces the need for consideration and measures to deal with deformation caused by heat. Conventionally, in telescopes used in space, deformation of the main reflector caused by heat generated by equipment and sunlight has the greatest impact on telescope performance. Therefore, reducing the need for consideration and measures to deal with deformation caused by heat generated by equipment is a significant advantage.

[0104] The reflector device according to the present disclosure may not use the support actuator to correct the mirror surface shape of the main reflector. For example, instead of an actuator for each supported point, an actuator for changing the position of the rear disk member 2 relative to the rear structural frame 3 may be provided.

[0105] Conventional lever-based reflector support devices are designed for telescopes with large reflectors and have a support mechanism that uses a lever to suppress deformation of the reflector due to its own weight, which changes when the telescope's elevation angle is changed. In a support mechanism that uses a lever, the reflector is supported at the point of application of the lever, and a counterweight equivalent to the load of the reflector acting on the point of application is placed at the point of force. Many patents have been filed for improvements to the force transmission method in support mechanisms that use a lever.

[0106] In space, there is no gravity, and the mirror surface cannot be corrected using a lever mechanism that uses a counterweight. In order to make the mirror surface of the reflector have an ideal shape in space, the reflector device according to the present disclosure is equipped with an actuator that actively displaces the mirror.

[0107] When the reflector device is used on Earth, it also uses a lever mechanism using a counterweight in combination with an actuator that actively displaces the counterweight. Because it is a hybrid system that uses both a counterweight and an actuator, the amount of displacement shared by the actuator only needs to be the amount of displacement shared by the counterweight minus the amount of displacement shared by the counterweight. Therefore, the driving force of the voice coil motor that drives the actuator can be smaller than when a counterweight is not used. By using a counterweight, the reflector device can be made lighter. Since an actuator is also used, adjustment of the counterweight weight can be simplified. The adjustment does not require much time, and the counterweight weight can be set to a weight that does not deform the mirror surface due to gravity, and there can be an error. If there is an error in the counterweight weight, the error can be shared by the actuator, allowing the mirror surface shape to approach the ideal shape.

[0108] Simplifying the adjustment of the counterweight weight allows the reflector to be made thinner and lighter, thereby reducing the manufacturing and adjustment costs of the reflector device. A thicker reflector reduces deformation of the mirror surface due to its own weight. Because the cost of adjusting the counterweight weight is high, the thickness of the reflector device has traditionally been set to a relatively thick value within the constraints of the reflector's weight. Increasing the reflector's thickness reduces the number of locations requiring shape correction on the mirror surface, and also reduces the number of counterweights whose weight needs to be adjusted. However, a thicker and heavier reflector increases the weight of the entire reflector device, increasing manufacturing costs. In the case of telescopes used in outer space (space telescopes), launch costs also increase.

[0109] In the reflecting mirror device according to the present disclosure, adjustment of the weight of the counterweight that offsets the weight of the reflecting mirror in an actuator that uses a lever can be simplified. Therefore, even if the reflecting mirror is made thinner and lighter and a large number of actuators are installed, the effort required to adjust the weight of the counterweight does not increase. In other words, in the reflecting mirror device according to the present disclosure, the reflecting mirror can be made thinner and lighter, and a large number of actuators can be installed. Because the reflecting mirror is lighter, the driving force that each actuator must output can be reduced, and the weight of each actuator can be reduced compared to conventional devices. Therefore, the weight of the reflecting mirror device can be reduced even when a larger number of actuators than conventional devices are used.

[0110] By reducing the thickness of the reflector, the amount of material used can be reduced, thereby reducing manufacturing costs. Furthermore, reducing the thickness of the reflector also allows for lower precision in the mirror surface shape during manufacturing, thereby reducing manufacturing costs. If the reflector is thick and difficult to deform, the range over which the actuator can correct the mirror surface shape is narrowed, and the reflector surface must be manufactured with high precision. In contrast, with the reflector device according to the present disclosure, even if the precision of the mirror surface shape of the reflector during manufacturing is lower than conventional, it can be corrected by the actuator to achieve the mirror surface shape with the precision required for observation. Because the precision of the mirror surface shape of the reflector during manufacturing can be lower than conventional, manufacturing costs for the reflector can be reduced.

[0111] If the reflector can be made thinner and lighter, the weight of the entire reflector assembly can be reduced, reducing manufacturing costs and, in the case of a space telescope, launch costs.

[0112] The reflector device according to the present disclosure facilitates the task of conducting tests on Earth to confirm the performance of a space telescope. To confirm the performance of a space telescope on Earth, it is necessary to evaluate the condition of the main reflector in a zero-gravity environment on Earth. Therefore, it has been necessary to measure the mirror surface in two states: one in which the space telescope alone or the satellite carrying the space telescope is inverted upside down. The two states are one in which the main reflector is facing the zenith and one in which the main reflector is facing perpendicular to the Earth's surface. The difference between the shapes of the mirror surface in the two states is defined as the shape of the mirror surface in the space environment. Achieving a state in which the main reflector is facing perpendicular to the Earth's surface requires a large support device to support and invert the attitude of the space telescope alone or the satellite carrying the space telescope. Testing with the main reflector facing perpendicular to the Earth's surface requires many complex procedures, increasing the time, effort, and cost required to adjust the mirror surface.

[0113] The reflector device according to the present disclosure uses an actuator that utilizes a lever, and a counterweight that counteracts the load of the main reflector is installed on the force point side (voice coil motor side) of the link member of the lever. Therefore, the mirror surface shape of the main reflector when the telescope is pointed toward the zenith is close to the mirror surface shape in a zero-gravity environment. Tests can be conducted to confirm the active control of the mirror surface by each actuator using a mirror surface shape that is close to the mirror surface shape in a zero-gravity environment as a reference. The reflector device according to the present disclosure does not require testing of the space telescope alone or the satellite carrying the space telescope upside down. Tests for assembling the telescope and verifying its performance can be conducted efficiently, significantly reducing at least one of the time, effort, and cost required to adjust the mirror surface.

[0114] The reflector device according to the present disclosure does not employ a drive system based on a mechanical system that generates friction, such as a gear system, but instead employs a non-contact force transmission system called a voice coil motor system. This solves the problem of uncertainty in the reference position when the surrounding structure supporting the main reflector undergoes thermal or moisture deformation, a common problem in space. The brakes of each actuator can be unlocked, preventing the voice coil motor from generating driving force, placing the reflector device in a reaction-force-free state. The reaction-force-free state is a state in which the mirror surface is unaffected by deformation of the surrounding structure and no reaction force is applied to the main reflector. In the reaction-force-free state, the main reflector 1 is completely free, releasing the internal forces generated in the main reflector during assembly on the ground and minimizing distortion of the mirror surface. The mirror surface position in the reaction-force-free state is the reference position. After placing the mirror surface in the reaction-force-free state, each actuator can be used to apply a displacement that offsets any deviation from the ideal mirror surface shape, thereby bringing the mirror surface closer to the ideal mirror surface shape.

[0115] The reflector device according to the present disclosure can easily recreate a mirror surface in a reaction-force-free state. In other words, the mirror surface can be returned to its natural state at any time without applying any unnecessary force to the main reflector. Therefore, even if structural components are displaced due to aging or other reasons, the mirror surface can easily approach the ideal mirror shape. Furthermore, the effects of control system hysteresis and error accumulation can be completely reset by entering a reaction-force-free state. The mirror shape can then be corrected with the same precision at any time from the reaction-force-free state using the actuator. After the actuator has corrected the mirror surface to a shape close to the ideal mirror shape, the brake is locked and the voice coil motor is de-energized. This allows the corrected mirror shape to be maintained. With the corrected mirror shape, unnecessary internal forces are not applied to the main reflector, allowing the main reflector to maintain the corrected mirror shape for a long time.

[0116] Even when the reflector device is used on Earth, the brakes of each actuator can be unlocked and the voice coil motor generates a driving force, allowing only gravity to act on the reflector. The state in which only gravity acts on the reflector device is called the unconstrained state. The reflector device according to the present disclosure can easily reproduce the unconstrained state. By using the unconstrained state as the initial state for setting the shape of the mirror surface, the procedure for correcting the mirror surface shape of the main reflector can always be the same, and the accuracy of the correction of the mirror surface shape can also be constant. After correcting the mirror surface shape, the brakes of each actuator can be activated, allowing the mirror surface shape to be maintained even when used on Earth.

[0117] The above operation and effects can also be obtained in a reflector device when the support actuators are not used to correct the mirror surface shape of the reflector. In the reflector device 50, three support actuators 5 supporting three supported locations 13 are used to correct the mirror surface shape of the main reflector 1. Therefore, more locations on the main reflector 1 can be controlled for the amount of displacement than when the support actuators 5 are not used to correct the mirror surface shape. Because there are more locations on the main reflector 1 where the amount of displacement can be controlled, more deformation modes can be corrected. Furthermore, in deformation modes that can be corrected even when the support actuators 5 are not used to correct the mirror surface shape, the accuracy of deformation correction is improved.

[0118] When the support actuator is not used to correct the mirror surface shape of the reflecting mirror, the mirror surface shape adjustment device receives mirror surface shape data 81 and controls the voice coil motor 8 so that the mirror surface 1A takes on a shape that minimizes the difference from the ideal mirror surface data 81.

[0119] The above describes in detail preferred embodiments, but the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims.

[0120] Various aspects of the present disclosure are summarized below as appendices.

[0121] (Supplementary Note 1) A reflecting mirror having a mirror surface that reflects electromagnetic waves, three supported points provided on the back surface of the mirror surface, and a predetermined total number of shape correction points provided on the back surface; a structural member that is present on the back surface side of the reflecting mirror, opposite to the side where the mirror surface is present, and supports the reflecting mirror; three support parts that are provided on the structural member and connected to each of the supported points to support the reflecting mirror; and shape correction parts that are provided on the structural member and are the same number as the shape correction points and change the position of each of the shape correction points in the optical axis direction that is a direction parallel to the optical axis of the reflecting mirror, A reflector device, wherein the shape correction unit includes a support column provided on the back surface of the structural member, which is the surface opposite to the side where the reflecting mirror is located, a link member provided rotatably around a fulcrum provided on the support column, a rod-shaped member having one end attached to the link member and the other end connected to the shape correction location, and a link drive unit provided on the link member on the side opposite to the point where the rod-shaped member is attached with respect to the fulcrum at a position greater than the point where the rod-shaped member is attached, and generating a force to move the link member in the optical axis direction. (Appendix 2) The reflector device described in Appendix 1, wherein the shape correction unit has a brake that prevents the link member from rotating. (Appendix 3) The reflector device described in Appendix 2, wherein the brake is provided on the same side of the link member with respect to the fulcrum as the link drive unit, and prevents the link member from moving relative to the structural member. (Supplementary Note 4) The reflecting mirror device according to Supplementary Note 2 or Supplementary Note 3, wherein the brake maintains a state in which the link member does not rotate relative to the structural member when power is not supplied to the shape correction unit. (Supplementary Note 5) The reflecting mirror device according to any one of Supplementary Notes 1 to 4, wherein, in the shape correction unit, a difference in moment due to gravity acting on both sides of the fulcrum is equal to or less than a determined upper moment upper limit value. (Supplementary Note 6) The reflecting mirror device according to any one of Supplementary Notes 1 to 5, wherein the link drive unit applies an electromagnetic force to the link member without contacting the link member. (Supplementary Note 7) The reflecting mirror device according to Supplementary Note 6, wherein the link drive unit is a voice coil motor.(Supplementary Note 8) The reflecting mirror device according to any one of Supplementary Notes 1 to 7, wherein the support part has a fixed part fixed to the structural member, a movable part movable in the optical axis direction relative to the fixed part and connected to the supported location, and a movable part drive part that generates a drive force to move the movable part. (Supplementary Note 9) The reflecting mirror device according to Supplementary Note 8, wherein the support part has a threaded rod that has a male thread on a side surface and engages with the movable part and rotates to move the movable part relative to the fixed part, and the movable part drive part generates the drive force to rotate the threaded rod. (Supplementary Note 10) The reflecting mirror device according to Supplementary Note 8 or Supplementary Note 9, wherein the movable part has a support rod-shaped member connected to the supported location, and a support link member to which the support rod-shaped member is connected and rotatable around a support fulcrum, and a support pillar is provided on the back surface of the structural member on which the support fulcrum is provided, and the drive force generated by the movable part drive part acts on a force point provided on the opposite side of the support link member with respect to the support fulcrum from a point of application where the support rod-shaped member is connected to the support link member, and at a point whose distance from the support fulcrum is greater than the distance between the point of application and the support fulcrum. (Supplementary Note 11) The reflecting mirror device according to Supplementary Note 10, wherein the support part has a support brake that prevents the support link member from rotating. (Supplementary Note 12) The reflecting mirror device according to Supplementary Note 11, wherein the support brake is provided on the same side of the support link member with respect to the support fulcrum as the movable part drive part, and prevents the support link member from moving relative to the structural member. (Supplementary Note 13) The reflector device according to Supplementary Note 12, wherein the support brake maintains the support link member movable relative to the structural member when power is not supplied to the support portion.(Supplementary Note 14) The reflector device according to any one of Supplementary Notes 1 to 13, wherein the reflector is circular when viewed from the optical axis direction, the total number is the product of the number of arrangement circles, which is an integer of 2 or more, and the number of same radius, which is also an integer of 2 or more, when viewed from the optical axis direction, on each of the arrangement circles, which are circles having different radii and centered on the mirror surface center, which is the center of the circle, the same number of shape correction points are arranged around the mirror surface center with rotational symmetry the number of times the same radius, and the shape correction points arranged on the arrangement circle having a certain radius are arranged on the bisector of the angle formed at the mirror surface center by two line segments connecting each of the shape correction points to the mirror surface center and two circumferentially adjacent shape correction points arranged on the arrangement circle adjacent in the radial direction of the circle. (Supplementary Note 15) The reflector device according to any one of Supplementary Note 8 to Supplementary Note 13, wherein the reflector is circular when viewed from the optical axis direction, the total number is the product of the number of arrangement circles, which is an integer of 2 or more, and the number of same radius, which is a multiple of 3, when viewed from the optical axis direction, on each of the arrangement circles, which are as many as the number of arrangement circles and each having a different radius and centered on the mirror surface center, which is the center of the circle, the same number of shape correction points are arranged around the mirror surface center with rotational symmetry the number of times as the same radius, the shape correction points arranged on the arrangement circle having a certain radius are arranged on the bisector of the angle formed at the mirror surface center by two line segments connecting each of the shape correction points to the mirror surface center and two circumferentially adjacent shape correction points arranged on the arrangement circle adjacent in the radial direction of the circle, and the shape correction points are arranged on each of three straight lines connecting each of the three supported points to the mirror surface center. (Supplementary Note 16) The reflecting mirror device according to Supplementary Note 14 or Supplementary Note 15, wherein the number of arranged circles is 3 and the number of same-radius circles is 6. (Supplementary Note 17) A reflecting mirror surface adjustment system comprising: the reflecting mirror device according to any one of Supplementary Note 1 to Supplementary Note 16; a wavefront sensor that is arranged in front of the reflecting mirror device in the optical axis direction and measures the shape of the mirror surface; and a mirror surface shape adjustment device that receives mirror surface shape data that is data representing the shape of the mirror surface measured by the wavefront sensor, and controls the link drive unit so that the mirror surface takes on a shape that minimizes the difference from ideal mirror surface data that is data representing the shape that the mirror surface should take.(Appendix 18) The mirror surface shape adjustment device is a reflective mirror surface adjustment system described in Appendix 17, which includes: a mode decomposition unit that calculates a mode decomposition result, which is the weighting coefficient that becomes closer to the differential shape data, which is the difference between the mirror surface shape data and the ideal mirror surface data, by weighting and superimposing the Zenikel modes to be suppressed, and the differential shape data; a displacement amount calculation unit that calculates the displacement amount in the optical axis direction at each of the shape correction points based on the mode decomposition result; and a drive control unit that controls the link drive unit so that each of the shape correction points moves in the optical axis direction by the displacement amount. (Appendix 19) A reflecting mirror surface adjustment system comprising: a reflecting mirror device as described in any one of Appendices 8 to 13 and Appendices 15; a wavefront sensor arranged in front of the reflecting mirror device in the optical axis direction to measure the shape of the mirror surface; and a mirror surface shape adjustment device that receives mirror surface shape data, which is data representing the shape of the mirror surface measured by the wavefront sensor, and controls the link drive unit and the movable part drive unit so that the mirror surface takes on a shape that minimizes the difference from ideal mirror surface data, which is data representing the shape that the mirror surface should take. (Appendix 20) The mirror surface shape adjustment device is a reflective mirror surface adjustment system described in Appendix 19, which includes: a mode decomposition unit that calculates a mode decomposition result, which is the weighting coefficient that becomes closer to the differential shape data, which is the difference between the mirror surface shape data and the ideal mirror surface data, by weighting and superimposing the Zenikel modes to be suppressed, to the differential shape data; a displacement amount calculation unit that calculates the amount of displacement in the optical axis direction at each of the shape correction points and the supported points based on the mode decomposition result; and a drive control unit that controls the link drive unit and the movable part drive unit so that each of the shape correction points and the supported points moves in the optical axis direction by the displacement amount.

[0122] 50 Reflector device, 1 Main reflector (reflector), 1A Mirror surface, 1B Rib, 1C Supported portion, 1D Corrected portion, 1E Spherical bearing, 1F Optical path opening, 2 Rear disc member (structural member), 2A Through hole, 2B Optical path opening, 3 Rear structural frame (structural member), 3A Frame support member, 3B Connected portion, 3C Rib, 4 Connecting member (structural member), 4A Opening, 5 Support actuator (support portion), 5A Support column (support rod-shaped member), 5B Fixed portion, 5C Movable portion, 5D Spring, 5E Link member (support link member), 5F Annular protrusion, 5G Nut storage portion, 5H Nut, 5J Threaded rod, 5K Tip disc, 5L Ball, 5M Motor storage portion, 5N Stepping motor (movable part drive part), 5P gear mechanism, 5Q force point, 5R action point, 5S rotation axis (fulcrum), 6 shape correction actuator (shape correction part), 6A rod spring (rod-shaped member), 6B link member, 6C support, 6D rotation axis (fulcrum), 6E action point, 6F force point, 6G rod spring mounting part, 7 support actuator (support part), 7A fixed part, 7B moving part, 7C stepping motor (movable part drive part), 7D threaded rod, 7E gear mechanism, 7F nut, 7G thermal deformation relief spring, 8 voice coil motor (link drive part), 8A permanent magnet, 8B electromagnet, 8C connection part, 8D weight, 9 brake, 9A brake plate, 9B brake pad, 9C spring, 9D Electromagnet, 10 Displacement meter, 11 Pivot member (support pillar), 11A Fixed plate, 11B Movable plate, 11C First swash plate, 11D Second swash plate, 11E Third swash plate, 11F Rotation shaft (fulcrum), 12 Fulcrum pivot member (support pillar), 12F Rotation shaft (support fulcrum), 13 Connection pivot member, 13F Rotation shaft, 14 Brake (support brake), 14A Brake plate, 14B Brake pad, 14C Spring, 14D Electromagnet, 60 Secondary mirror support frame, 61 Secondary mirror, 70 Reflection mirror surface adjustment system, 71 Wavefront sensor, 72 Mirror surface shape adjustment device, 73 Network, 74 Communication unit, 75 Mode decomposition unit, 76 Displacement amount calculation unit, 77 Actuator control unit (drive control unit), 80 Data storage unit, 81 Ideal mirror surface data,82 mirror surface shape data, 83 differential shape data, 84 Zenikel mode data, 85 mode decomposition result, 86 actuator data, 87 actuator operation amount, LX optical axis.

Claims

1. A reflector having a mirror surface that reflects electromagnetic waves, three supported points provided on the back surface of the mirror surface, and a predetermined total number of shape correction points provided on the back surface; a structural member that is located on the back side of the reflector opposite to the side where the mirror surface is located and supports the reflector; three support parts that are located on the structural member and connected to each of the supported points to support the reflector; and shape correction parts that are located on the structural member and are the same number as the shape correction points and change the position of each of the shape correction points in the optical axis direction that is parallel to the optical axis of the reflector, The shape correction unit includes a support pillar provided on the back surface of the structural member, which is the surface opposite to the side where the reflecting mirror is located; a link member rotatably provided around a fulcrum provided on the support pillar; a rod-shaped member having one end connected to the shape correction location and the other end attached to the link member; and a link drive unit provided on the link member on the opposite side of the fulcrum from the point where the rod-shaped member is attached, at a position where the distance from the fulcrum is greater than the point where the rod-shaped member is attached, and which generates a force to move the link member in the optical axis direction.

2. The reflector device according to claim 1, wherein said shape correction section has a brake for preventing said link member from rotating.

3. A reflector apparatus as set forth in claim 2, wherein said brake is provided on the same side of said link member as said link drive unit with respect to said fulcrum, to prevent said link member from moving relative to said structural member.

4. A reflector device according to claim 2 or 3, wherein the brake maintains a state in which the link member does not rotate relative to the structural member when power is not supplied to the shape correction unit.

5. A reflecting mirror device according to any one of claims 1 to 4, wherein in said shape correction section, the difference in moment due to gravity acting on both sides of said fulcrum is equal to or less than a predetermined upper moment limit value.

6. A reflecting mirror device according to any one of claims 1 to 5, wherein the link drive unit applies an electromagnetic force to the link member without contacting the link member.

7. The reflector device according to claim 6, wherein said link drive unit is a voice coil motor.

8. A reflector device as claimed in any one of claims 1 to 7, wherein the support part has a fixed part fixed to the structural member, a movable part that is movable in the optical axis direction relative to the fixed part and connected to the supported location, and a movable part drive part that generates a drive force to move the movable part.

9. The reflector device according to claim 8, wherein the support part has a threaded rod with a male thread on the side that engages with the movable part and rotates to move the movable part relative to the fixed part, and the movable part drive part generates the drive force that rotates the threaded rod.

10. A reflector device as described in claim 8 or claim 9, wherein the movable part has a support rod-shaped member connected to the supported location, and a support link member to which the support rod-shaped member is connected and which is rotatable around a support fulcrum, and has a support pillar provided on the back surface of the structural member on which the support fulcrum is provided, and the driving force generated by the movable part driving part acts on a force point provided on the opposite side of the support link member with respect to the support fulcrum from the point of application where the support rod-shaped member is connected to the support link member, and at a point whose distance from the support fulcrum is greater than the distance between the point of application and the support fulcrum.

11. A reflector assembly as claimed in claim 10, wherein said support has a support brake to prevent said support link member from rotating.

12. A reflector device as set forth in claim 11, wherein the support brake is provided on the same side of the support link member as the movable part drive part with respect to the support fulcrum, to prevent the support link member from moving relative to the structural member.

13. The reflector apparatus of claim 12, wherein the support brake maintains the support link member movable relative to the structural member when power is not supplied to the support.

14. A reflecting mirror device according to any one of claims 1 to 13, wherein the reflecting mirror is circular when viewed in the optical axis direction, the total number is the product of the number of arrangement circles, which is an integer of 2 or more, and the number of same radius, which is also an integer of 2 or more, and when viewed in the optical axis direction, on each of the arrangement circles, which are circles having different radii and centered on the mirror surface center, which is the center of the circle, the same number of shape correction points are arranged around the mirror surface center with rotational symmetry the number of times the same radius, and the shape correction points arranged on the arrangement circle having a certain radius are arranged on the bisector of the angle formed at the mirror surface center by two line segments connecting each of the shape correction points to the mirror surface center and two circumferentially adjacent shape correction points arranged on the arrangement circle adjacent in the radial direction of the circle.

15. A reflecting mirror device according to any one of claims 8 to 13, wherein the reflecting mirror is circular when viewed in the optical axis direction, the total number is the product of the number of arrangement circles, which is an integer of 2 or greater, and the number of same radius, which is a multiple of 3, and when viewed in the optical axis direction, on each of the arrangement circles, which are circles with different radii and centered on the mirror surface center, which is the center of the circle, the same number of shape correction points are arranged around the mirror surface center with rotational symmetry the number of times as many as the same radius, and the shape correction points arranged on the arrangement circle having a certain radius are arranged on the bisector of the angle formed at the mirror surface center by two line segments connecting each of the shape correction points to the mirror surface center and two circumferentially adjacent shape correction points arranged on the arrangement circle adjacent in the radial direction of the circle, and the shape correction points are arranged on each of three straight lines connecting each of the three supported points to the mirror surface center.

16. A reflector device according to claim 14 or claim 15, wherein the number of circles arranged is three and the number of circles with the same radius is six.

17. A reflecting mirror surface adjustment system comprising: a reflecting mirror device as defined in any one of claims 1 to 16; a wavefront sensor arranged in front of the reflecting mirror device in the optical axis direction to measure the shape of the mirror surface; and a mirror surface shape adjustment device which receives mirror surface shape data representing the shape of the mirror surface measured by the wavefront sensor and controls the link drive unit so that the mirror surface takes on a shape that minimizes the difference from ideal mirror surface data, which is data representing the shape the mirror surface should take.

18. The mirror surface shape adjustment device is a reflecting mirror surface adjustment system as described in claim 17, which has: a mode decomposition unit that calculates a mode decomposition result, which is the weighting coefficient that becomes closer to the differential shape data, which is the difference between the mirror surface shape data and the ideal mirror surface data, by weighting and superimposing the Zenikel modes to be suppressed, and the differential shape data; a displacement amount calculation unit that calculates the amount of displacement in the optical axis direction at each of the shape correction points based on the mode decomposition result; and a drive control unit that controls the link drive unit so that each of the shape correction points moves in the optical axis direction by the displacement amount.

19. A reflecting mirror surface adjustment system comprising: a reflecting mirror device as defined in claims 8 to 13 and claim 15; a wavefront sensor arranged in front of the reflecting mirror device in the optical axis direction to measure the shape of the mirror surface; and a mirror surface shape adjustment device which receives mirror surface shape data representing the shape of the mirror surface measured by the wavefront sensor and controls the link drive unit and the movable part drive unit so that the mirror surface takes on a shape that minimizes the difference from ideal mirror surface data, which is data representing the shape the mirror surface should take.

20. The mirror surface shape adjustment device is a reflecting mirror surface adjustment system as described in claim 19, which has: a mode decomposition unit that calculates a mode decomposition result, which is the weighting coefficient that approximates the differential shape data, which is the difference between the mirror surface shape data and the ideal mirror surface data, by weighting and superimposing the Zenikel modes to be suppressed, to the differential shape data; a displacement amount calculation unit that calculates the amount of displacement in the optical axis direction at each of the shape correction point and the supported point based on the mode decomposition result; and a drive control unit that controls the link drive unit and the movable part drive unit so that each of the shape correction point and the supported point moves in the optical axis direction by the displacement amount.

Images