JP2006276429A - Lightweight reflecting mirror - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lightweight reflecting mirror which can be used for a large-diameter telescope mounted on a mobile object, an optical sensor or the like, and is made lighter. <P>SOLUTION: The mirror is provided with a core formed by applying a plurality of pole-shaped and polyangular pole-shaped hole drilling to a material that has foamed glass or glass ceramics, and a mirror finished surface member which uses the same or the same kind of material as the core and forms a mirror finished surface on the surface of non-foaming glass or glass ceramics having the linear expansion coefficient identical to or equivalent to the core. A flat joined surface formed on the hole side of the core is joined to a flat joined surface formed on the back face of the mirror finished surface member to integrate the core with the mirror finished surface member. By combining foaming of the core base material with processing of a pocket shape, larger effects of lightweighting can be obtained in comparison with a conventional mirror. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light-weight reflecting mirror that is mounted on a moving body such as an artificial satellite or a flying object and used for a telescope, an optical sensor, or an optical antenna.

A reflecting mirror used for a telescope, an optical sensor, or an optical antenna has a predetermined curvature surface for optically condensing light emitted from the ground surface or space. The light collecting ability depends on the aperture diameter of the reflecting mirror. A telescope, an optical sensor, or an optical antenna having a high condensing capability is required to have a reflector having a large aperture. In addition, in order to obtain a high resolution in a telescope or an optical sensor, it is necessary to suppress wavefront distortion due to reflection of the reflecting mirror, so that the reflecting mirror is required to have high surface accuracy. As described above, high-resolution telescopes and optical sensors require a large-diameter and high-surface accuracy reflecting mirror.
In a reflector used for a telescope, an optical sensor, or an optical antenna, a metal film such as aluminum or silver is formed as an optical reflection layer on a polishing plate such as quartz glass.

  In particular, reflectors mounted on moving objects such as artificial satellites and flying objects are severely limited in mass due to the launch capability of rockets and the like. Therefore, when trying to obtain a high light collecting ability in a telescope, an optical sensor or an optical antenna mounted on a moving body such as an artificial satellite or a flying object, it is necessary to make the reflecting mirror have a large diameter, which increases the mass. It becomes a problem. Therefore, for example, a light weight reflecting mirror as described in Patent Document 1 has been proposed.

Japanese Patent Laying-Open No. 2004-163803 (FIG. 1)

  In recent years, telescopes and optical sensors mounted on moving objects such as artificial satellites and flying objects have been required to have higher performance. To improve the imaging performance, reflecting mirrors with large apertures are mounted on moving objects. It is requested to do. As the aperture of the reflecting mirror increases, the mass of the mirror increases, so that there is a problem that the eigenvalue decreases due to insufficient rigidity, and a large load is likely to be generated by resonating with the main vibration mode of the moving body. In addition, there is a problem that the mass of the entire moving body increases due to the increase in the mass of the reflecting mirror, and the movement performance of the moving body deteriorates due to the increase in the moment of inertia.

  The present invention has been made to solve such problems, and an object thereof is to provide a lighter reflecting mirror.

The weight-reduced reflector according to the present invention includes a core formed by processing a plurality of cylindrical or polygonal column-shaped pocket holes in a glass or glass ceramic foamed material,
Using the same or the same kind of material as the core, and comprising a mirror surface member having a mirror surface formed on the surface of non-foamed glass or glass ceramic material having the same or equivalent linear expansion coefficient as the core,
The flat joint surface formed on the pocket hole side of the core, the mirror member and the planar joint surface formed on the back surface are joined together, and the core and the mirror member are integrated.

According to the present invention, there is an effect that it is possible to reduce the weight of a large-sized and large-diameter reflecting mirror without greatly impairing mechanical rigidity.
This is also effective for increasing the resolution, improving the signal-to-noise ratio, and increasing the efficiency of telescopes and optical sensors mounted on mobile objects such as artificial satellites and flying objects. It is also effective in improving the movement performance of a moving body equipped with a telescope and an optical sensor.

Embodiment 1 FIG.
FIG. 1 is a cross-sectional view showing the structure of a lightweight reflector according to Embodiment 1 of the present invention. 2A and 2B are cross-sectional views of the mirror member and the core, in which FIG. 2A is a side cross-sectional view, and FIG. 2B is a view in the A direction of the core.
In FIG. 1, the light weight reflecting mirror is configured by joining the opposite surface of the mirror member 1 to a core 2. The mirror surface member 1 and the core 2 are bonded or fused together by a bonding material 3 such as an inorganic adhesive or glass fusion bonding. When the mirror member 1 and the core 2 are fused, the respective joining surfaces (joining surfaces 4 and 6 to be described later) are polished in advance, then fused, and then heat-treated.

  The core 2 is formed by reducing the weight of a base material obtained by foaming glass or glass ceramic by forming a hole in a pocket shape. As the core 2, for example, it is preferable to use a specific gravity that is smaller than 1 to 2 by scattering bubbles, or a specific gravity that is about half or less compared to the same non-foamed glass or glass ceramic. . By combining foaming of the base material and pocket-shaped machining, a great light weight reduction effect can be obtained. At the time of foaming, it is preferable to perform sufficient strength and end face treatment so that the foam does not rupture due to the expansion of the bubbles within the temperature range of use, or the bubbles are solidified or cracked.

  As shown in FIGS. 2 (a) and 2 (b), the drilling of the core 2 is formed by grinding a cylindrical base material and digging a hole 5 having a triangular prism shape or a quadrangular prism shape, for example. Between the adjacent holes 5, ribs 7 that vertically and horizontally connect one side of the core are erected to constitute a structural member for obtaining a predetermined strength and rigidity even after weight reduction. An end surface of the rib 7, that is, a surface on one side of the core forms a joint surface 6 for joining the mirror surface 1. The joint surface 6 is formed so that the end surfaces of all the ribs are the same surface. The back surface on the other side of the core forms a flat surface, and forms a fixing surface for fixing the lightening reflecting mirror to an external structure such as a telescope or an optical sensor.

  The mirror member 1 has a curved surface 8 that forms a mirror surface by subjecting a base material made of non-foamed glass or glass ceramic made of the same material as the core to a mirror surface. For example, the specular member 1 has a specific gravity of about 2 to 3. The curved surface 8 is formed with a surface shape according to the optical design, such as a spherical surface, a hyperboloid surface, and an elliptical surface, and a curvature and a focal point are set. A mirror surface 9 is formed on the surface of the curved surface 8 by depositing or bonding a metal such as aluminum or silver. The back surface opposite to the mirror surface 9 of the mirror surface member 1 is a flat plane, and constitutes a bonding surface 7 to be bonded to the bonding surface 6 of the core 2.

In this embodiment, foamed glass or glass ceramic is used for the core occupying most of the volume of the reflecting mirror. By reducing the specific gravity of the core in this way, it is possible to reduce the total mass of the core to about half or less compared to the case where the non-foamed glass is simply subjected to pocket-shaped hole processing. Moreover, since the rib which comprises a structural member is formed in the core, the deterioration of the intensity | strength and rigidity accompanying weight reduction can also be suppressed.
For example, if the core 2 is formed of foamed glass having a specific gravity less than half that of non-foamed glass, the mass can be reduced to less than half that of non-foamed glass. Can be reduced in weight. In this case, if the rigidity is about the same, the resonance frequency can be increased by 15% or more. For example, if the resonance point when the reflecting mirror is formed of non-foamed glass is 50 Hz, the resonance point can be improved to near 60 Hz by using foamed glass for the core 2.

  Moreover, since the joining surface of the core 2 and the mirror surface member 1 has a planar shape, the core 2 and the mirror surface member 1 can be easily joined and the core 2 and the mirror member 1 can be easily shaped and bonded. That is, when the back surface of the mirror surface member 1 is a curved surface, the processing becomes extremely inefficient, and it is difficult to make the surface shape of the joint surface of the mirror surface member 1 and the core 2 completely the same. Although it becomes difficult to join the mirror member 1 and the core 2, in this embodiment, since the joining surface is flat, workability is remarkably improved.

Embodiment 2. FIG.
FIG. 3 is a cross-sectional view showing a cross-sectional structure of the mirror member 1 according to the second embodiment.
This embodiment is characterized in that a pocket-shaped blind hole is formed on the mirror member 1.

  In FIG. 3, the mirror member 1 has a pocket-shaped hole 10 formed on the back surface of non-foamed glass or glass ceramic constituting the mirror member 1. Ribs 11 are formed between the holes 10. Thereby, since the mirror surface member 1 is reduced in weight, a lighter and lighter reflecting mirror can be formed. Moreover, since the mirror surface member 1 is reduced in weight and the specific gravity difference between the core 2 and the mirror surface member 1 is reduced, it is possible to configure a light-weight reflector having higher strength and higher rigidity. Further, the mirror member 1 can be easily reduced in weight without making the back surface of the mirror member 1 opposite to the mirror surface 9 a curved surface.

  It should be noted that the height of the mirror surface 9 and the joint surface 4 gradually increases as the distance from the central portion of the mirror surface 9 approaches the peripheral portion, and the hole 10 should be deepened accordingly. Accordingly, the curvature surface along the mirror surface 9 shown by the broken line in FIG. 3 is supported by the ribs 11 along the mirror surface shape, so that the bending deformation of the mirror surface 9 in the mirror member 1 is made more uniform. can do.

Embodiment 3 FIG.
FIG. 4 is a diagram showing the configuration of the core according to the third embodiment. In this embodiment, the core 2 exemplified in the first embodiment is constituted by a cylindrical core 20 and a plate-shaped back plate 21.

The core 20 is formed by providing a through hole 30 having a triangular prism shape or a quadrangular prism shape on a cylindrical base material. Ribs 31 are provided between adjacent through holes 30. The core 20 has a form in which a through hole 30 is vacated like a lotus root. A back plate 21 is joined to the back surface of the core 20. The back plate 21 is formed of foamed glass or glass ceramic made of the same material as the core. The mirror surface member 1 and the core 20, and the core 20 and the back plate 21 are bonded to the bonding surface 4 and the bonding surface 6, and the bonding surface 22 and the bonding surface 23, respectively.
In addition, when vapor-depositing the mirror surface 9, it is good to carry out after confirming the joining state of the mirror surface member 1 and the core 2 in advance. That is, before vapor deposition of the mirror surface 9, since the joined body of the mirror surface member 1 and the core 2 is colorless and transparent, the state of the joint surface can be seen. Can be confirmed.

  In this embodiment, the core 20 is lightened by providing a through hole 30 in the core 20. In this case, as compared with the case where the pocket-shaped hole 5 is formed by processing the blind hole from one direction of the core 2 as in the first embodiment, the hole processing can be performed more efficiently. For example, by drilling the through hole 30 by water jet machining or the like, the machining time can be reduced by 10 times or more compared to the case of pocket-shaped blind hole machining by grinding. Is significantly improved.

  As described above, the lightweight reflector according to Embodiments 1 to 3 can manufacture a large-sized, large-diameter high-surface-precision reflector with a light weight without greatly impairing mechanical rigidity. This lightweight reflector is useful for increasing the resolution of telescopes and optical sensors mounted on moving bodies such as artificial satellites and flying objects, improving the SN ratio, and increasing the light collection efficiency of optical antennas.

It is a figure which shows the weight reduction reflective mirror by Embodiment 1 of this invention. It is sectional drawing which shows the structure of the core by Embodiment 1 of this invention. It is sectional drawing which shows the structure of the core by Embodiment 2 of this invention. It is sectional drawing which shows the structure of the core by Embodiment 3 of this invention.

Explanation of symbols

  1 mirror surface member, 2 core, 3 adhesive or fused portion, 5 holes, 10 holes, 20 cores, 21 back plate, 30 through holes

Claims (6)

A core formed by applying a plurality of cylindrical or polygonal pocket holes to a glass or glass ceramic foamed material,
Using the same or the same kind of material as the core, and comprising a mirror surface member having a mirror surface formed on the surface of non-foamed glass or glass ceramic having the same or equivalent linear expansion coefficient as the core,
A planar joining surface formed on the pocket hole side of the core and a planar joining surface formed on the back surface of the mirror member are joined, and the core and the mirror member are integrated. A lightweight reflector.   The weight-reduced mirror according to claim 1, wherein the core and the mirror member are joined by bonding with an inorganic adhesive or by fusion bonding.   2. The light-weight reflecting mirror according to claim 1, wherein the bonded surfaces of the core and the mirror member are polished and bonded by bonding with an inorganic adhesive or after fusion.   The weight-reduced reflecting mirror according to claim 3, wherein a heat treatment is performed after the joining.   The light-weight reflecting mirror according to claim 1, wherein the mirror member is formed with a plurality of circular or polygonal pocket holes along the mirror shape. A core formed by applying a plurality of cylindrical or polygonal through-holes to glass or glass ceramic foamed material;
A mirror surface member having a mirror surface formed on the surface of non-foamed glass or glass ceramic material having the same or equivalent linear expansion coefficient as the core;
Using the same or the same kind of material as the core, comprising a non-foamed or foamed glass or glass ceramic back plate having a linear expansion coefficient equivalent to the core,
The mirror member and the back plate are integrally joined by bonding with an inorganic adhesive or by fusing at a joining surface having a planar shape formed on each of the cores with the core interposed therebetween.

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