JPH03293301A - Reflecting mirror - Google Patents

Abstract

PURPOSE:To simplify the structure by fixing a reflecting film obtained by forming a metallic thin film of Al, Ag, etc., having high reflectivity on a plastic film to an annular or discoid member. CONSTITUTION:When an annular member 2 is forced in with its lower surface in contact with a film 1, the film 1 is firstly bent by the indented parts on the outer peripheral sides of the annular members 2 and 3 and pressed in, then the film 1 is forced in by the indented parts on the inner peripheral sides while keeping a contact surface with the protrusion of the member 2, and a tension corresponding to the inner peripheral recess of the member 3 is exerted on the film 1 over its whole periphery. When the member 2 is completely forced into the member 3, annular member fixing flanges 3a and 3c are fixed by a bolt 4, hence the tension exerted on the film 1 is kept, and the flatness of the film 1 is maintained. Since the plastic film 1 obtained by forming a high- reflectivity metallic thin film 1a on a base material by vapor deposition, etc., is used, the rough working, lapping, etc., of a reflecting mirror as in the conventional method are not needed, and an inexpensive mirror surface of simple structure is obtained in a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a reflecting mirror that is used for changing the optical path of various types of light rays, for solar concentrators in space, and the like.

(Prior Art) Conventionally, a reflecting mirror used for changing the optical path of a light beam has been formed by depositing a single layer or multiple layers of a material with high reflectance on a polished surface such as glass or metal.

FIG. 10 shows an example of a reflector for a conventional space solar concentrator, in which the base material 20 has a single-plate structure with only a CFRP skin, and a glass processing layer 21 is provided on the surface. The surface is polished. Then, aluminum vapor deposition 23 is applied to the glass polished surface 22 of this polished surface to form a reflecting mirror.

Furthermore, with the progress of space development, the development of space stations, space shuttles, etc. is progressing in concrete terms. Launching fuel from Earth as an energy source for activities in space would be extremely expensive, so conventional methods have been used to condense sunlight in space and use it as an energy source. Development of optical devices is progressing.

Figure 12 shows a conceptual diagram of a conventional space solar concentrator. The reflector 24 of the solar light concentrator for space needs to have a light weight at the time of rocket launch, to be able to be stored compactly at the time of launch, and to not be mechanically deformed or damaged by the high load at the time of launch. Good light gathering performance in space is required. In particular, the use of concave mirrors is being considered to improve light collection performance. This requires comprehensive development of materials, structures, and manufacturing techniques, and research and development has been progressing at each company.

By the way, since a solar light concentrator generates electricity by reflecting sunlight 25 with a reflecting mirror 24 so that it enters the heat receiver 26, a reflecting mirror that forms reflected light with dimensions smaller than the dimensions of the heat receiving part of the heat receiver 26 is used. If so, it is not necessarily necessary to have a concave surface, and a plane mirror may be used. Concave mirrors are suitable for operating high-temperature heat receivers because each mirror has a large condensing density.For low-temperature heat receivers, a flat mirror may be used, and both can be used depending on the purpose of use.

Next, an example of the reflecting mirror 24 will be explained with reference to FIG. 11. In the figure, 27 is a thermosetting resin film that is cured by solar heat, and materials 28 and 28 are vapor-deposited on both sides of the film. 29
is a film that transmits sunlight, and is sealed and fixed to the thermosetting resin film 27 and the outer periphery by a support material 30. On orbit, xenon gas 31 is pressurized and sealed between the thermosetting resin film 27 and the film 29 as shown by the two-dot chain line, and the resin film 27 and film 29 are respectively expanded outward, and the resin film 27 is cured. After that, the gas 31 is removed to form a concave reflecting mirror.

(Problem to be solved by the invention) Conventionally, manufacturing of this type of reflecting mirror requires processing of the base material, especially surface accuracy of the reflecting surface, so polishing is performed and then surface coating is performed in a batch method. is applied. Therefore, it takes a long time to manufacture and is expensive, and this tendency becomes more pronounced as the reflecting mirror becomes larger. In addition, if the reflectance deteriorates during use or is damaged during handling, it must be replaced with a new one.

Furthermore, in the reflecting mirror for a space solar concentrator as shown in FIG. 11, the supporting member 30 requires a sealing function including gas pressurization supply and exhaust functions, so the structure of the supporting member is complicated. In addition, it is necessary to pressurize the gas in orbit and degas it after the resin has hardened. Additionally, gas cylinders, pressure reducing valves, and other assemblies and auxiliary equipment had to be transported from the ground, making it difficult to reduce the weight and store the space during launch.

The present invention aims to provide a reflective mirror that can solve the above-mentioned conventional problems by using a reflective film in which a metal material with a high reflectance such as AI or Ag is vapor-deposited.

(Means for solving the problem) Therefore, the present invention provides A7. This is a reflective film formed by sputtering, pasting, etc., on a plastic film with a metal thin film with a high reflectance such as Ag, and attached to a ring-shaped or disk-shaped member.This is a means to solve the problem. It is something to do.

In addition, the present invention is made by attaching the reflective film and a transparent plastic film to be overlapped with the reflective film to a ring-shaped member via a sealing member, and filling the gap with gas at about atmospheric pressure. It is intended as a means of

(Function) By sandwiching the reflective film, uniform tension is applied to the entire surface of the reflective film, so that the reflective film becomes flat on the surface of the ring-shaped or disk-shaped member.

Furthermore, two of the reflecting mirrors formed by the clamping operation under atmospheric pressure.
Gas at about atmospheric pressure is sealed between the two films, so when this is exposed to the vacuum of space, the two films swell outward due to the pressure difference between the inside and outside, and when viewed from the transparent film side, The film forming the thin film has a concave shape.

(Embodiments) The present invention will be described below with reference to embodiments of the drawings. FIGS. 1 to 8 show embodiments of the present invention.

First, the first embodiment shown in FIGS. 1 to 3 will be explained.
1 is a thin film with aluminum vapor deposition 1a applied on one side. 2 and 3 are ring-shaped members that apply tension to the film 1 and fix it in the tension-applied state, and in the mating portion of both ring-shaped members 2 and 3, one is convex and the other is concave, and the outer circumference is closer to the inner circumference. The amount of unevenness is thicker than that of (and both ring-shaped members 2.3
A fixing collar 3a is provided on the outer periphery of the holder.

More specifically, as shown in FIGS. 2 and 3, the ring-shaped member 2.3 has four fixing flanges 3a+30 at corresponding positions on the outer periphery at equal angles. The collar 3a is provided with a guide portion 3a' for positioning with one of the fixing collars 3c. When assembling, aluminum vapor deposition 1a is applied on the ring-shaped member 3.
Place the film 1 that has been
a' and the fixing collar 3c, push it into the ring-shaped member 3, and when the film 1 is pushed in a little, attach the fixing bolt 4, and further tighten this bolt 4 to attach the desired shape to the film 1. Tension is applied and maintained to maintain the flatness of the film 1.

Next, the effect will be explained. When the lower surface of the ring-shaped member 2 comes into contact with the film 1 and pushing starts, the film 1 is first bent and pushed in by the uneven parts on the outer circumferential side of both ring-shaped members 2 and 3, and then the film 1 is pushed in by the uneven parts on the inner circumferential side. The film 1 is pushed into the convex portion of the ring-shaped member 2 while maintaining the contact surface, and a tension equal to the amount of the inner peripheral side of the ring-shaped member 3 is applied to the film 1 over the entire circumference. Ring-shaped members 2, 3
When it is completely pushed in, the ring-shaped member fixing collar 3a
and 3C are fixed with bolts 4 to maintain the tension acting on the film 1 and maintain the flatness of the film 1.

Next, a second embodiment of the present invention will be explained with reference to FIGS.
is applied. Further, 8 is a transparent film, 9 and 10 are ring-shaped members, 6 is an O-ring, and the same ring-shaped member 9.
10 both have arms 9a and 10a on the outer periphery of the ring,
It is connected by a hinge, and has clamp parts 9b and 10b on the outer periphery facing the arms 9a and 10a for fixing ring-shaped members 9 and 10. Also, both ring-shaped members 9
, 10, a groove is provided in the ring-shaped member 10 so that a seal can be formed by an O-ring 6.

Next, when assembling, first open the ring-shaped member 9, place the aluminum vapor-deposited 1aL film 1 on the ring-shaped member 10, and then align it with the O-ring groove position of the ring-shaped member 10.
The ring 6 is placed on the aluminum vapor-deposited film 1, the transparent film 8 is further placed on the O-ring 6, the ring-shaped member 9 is closed, and the ring-shaped member 10 is fixed. Then, by performing this work under atmospheric pressure conditions such as on a space station, the aluminum vapor-deposited film 1 and the transparent film 8 are combined.
In between, gas at about atmospheric pressure is sealed by an O-ring 6. When this assembled reflector is taken out to outer space where the condenser is installed in a high vacuum state, each film is moved to
As shown by the dotted chain line, it bulges out into space, creating a concave mirror.

Next, FIGS. 6 to 8 show a third embodiment of the present invention, and a second embodiment of the present invention is shown in FIGS.
This embodiment is designed to simplify assembly and improve precision compared to the embodiment. This third embodiment differs in structure from the second embodiment in that there are three ring-shaped members 1112 and 13, and the central ring-shaped member 12 has grooves for the O-ring 6 on both the upper and lower sides. Ring-shaped member 11 with upper and lower O-ring grooves
The point is that the protrusion 14 is inserted so as to enter the angle 13 degrees.

Also, as seen in FIG. 7, the upper and lower ring-shaped members 11
．． The outer periphery of 13 is wedge-shaped 15, and is fixed and tightened by a corresponding wedge-shaped half-split clamp ring 7. With these, the two films 1.8 are individually attached, and tension can be applied to the film 1.8 by the projections 14 of the central ring-shaped member 12 to the upper and lower ring-shaped members 11.13. This makes it possible to make the film surface uniform. Further, almost the entire circumference of the upper and lower ring-shaped members 11 and 13 can be clamped by the ring 7, and sealing performance and film surface accuracy can be improved. Note that lla and 12a are arms connected by hinges.

In the condenser, the light reflected by the reflecting mirror 24 only needs to enter the heat receiving section, so the curvature of the reflecting mirror 24 does not need to be constant as long as it is within a predetermined range, as shown in FIG. In other words, during manufacturing, the maximum curvature (solid line in Figure 9) at which the reflected light 32 enters the heat receiving part of the heat receiver 26 is selected, and even if the internal gas leaks a little, good light convergence is maintained up to the curvature shown by the dotted line in the figure. It is now possible to do so.

Therefore, in the present invention, in order to improve this sealing property, as shown in FIGS. 6 to 8, tension is applied uniformly when fixing the films 1 and 8.
8 to prevent the occurrence of wrinkles on the sealing surface and flatten the sealing surface.
5, and by making it possible to uniformly tighten the entire circumference of the upper and lower ring-shaped members 11 and 13 with the corresponding wedge-shaped half-split clamp ring 7, the deformation of the O-ring 6 can be made uniform. can.

(Effects of the Invention) As described above, the present invention uses a plastic film in which a metal thin film with a high reflectance is formed by vapor deposition on the base material, so rough processing and polishing are not required unlike conventional reflecting mirrors. The film can be directly formed on the reflective surface, the structure is simple, it can be obtained at low cost, and a mirror surface can be obtained in a short delivery time. In addition, once the ring-shaped member to which the reflective film is attached can be manufactured, it can be used for many years, and if the reflectance deteriorates during use or the mirror surface is damaged, all you need to do is replace the film. Easy to maintain. In particular, like the reflector of a space solar concentrator, in zero gravity there is no external force, flatness is always maintained, and the present invention can be stored very compactly in a rocket or shuttle. Reflectors are extremely effective.

In addition, the present invention can easily create a concave reflector with a predetermined radius of curvature with high precision and compactness by simply sealing gas between the reflective film and the transparent film used in the reflector, and by using the differential pressure with outer space. can be manufactured. Furthermore, if the reflector is damaged by a flying object or the like during assembly or use, it can be easily and inexpensively repaired by simply replacing the film. In addition, during launch when used as a reflector for a space solar concentrator, the two types of films, the reflective film and the transparent film, are rolled into rolls to withstand impact forces and to be placed inside the ring-shaped member for assembling the reflector. By storing the film roll in, compact storage becomes possible.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of a reflecting mirror according to a first embodiment of the present invention;
2 is a plan view of the same, FIG. 3 is a second enlarged sectional view taken along line A-A, FIG. 4 is a side sectional view of a reflecting mirror according to a second embodiment of the present invention, and FIG. 6 is a side sectional view of a reflecting mirror according to the third embodiment of the present invention, and FIG. 7 is a sectional view taken along line C in FIG. 6.
~C sectional view, FIG. 8 is a view taken along the line D-D in FIG. 6, FIG. 9 is an explanatory diagram of the curvature of the reflecting mirror, and FIG. FIG. 11 is a side sectional view of a conventional reflecting mirror for a space solar concentrator, and FIG. 12 is a perspective view of a solar concentrator in which the same reflecting mirrors are assembled. Description of main parts of the figure Film aluminum vapor deposition 9, 10. lL12.13 0-ring Transparent film ring-shaped member 2nd page Figure 9 Figure 11 Figure 12

Claims (2)

[Claims] (1) A reflective mirror characterized in that a reflective film formed by depositing, sputtering, pasting, etc. a thin metal film of high reflectance such as Al or Ag on a plastic film is attached to a ring-shaped or disk-shaped member. (2) In the reflective mirror according to claim 1, the reflective film and a transparent plastic film overlaid thereon are attached to a ring-shaped member via a sealing member, and gas at about atmospheric pressure is sealed between the two films. A reflective mirror characterized by: