JPH0565400B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to an improvement in an infrared guide that is included in a radiation cooler mounted on an artificial satellite and guides infrared rays to an infrared detector.

(b) Background of the technology Photon detectors with elements such as HgCdTe are used in infrared detectors for infrared cameras mounted on recent resource exploration satellites. Although these are highly sensitive and have a fast response time, they only operate at extremely low temperatures of 100°C, so a special cooling mechanism is required. The detector must also have a structure that allows it to exhibit a high degree of reliability even under the special environment of outer space. Therefore, there is a strong demand for the development of a radiation cooler equipped with an infrared guide that can almost completely prevent the effects of stray light and outgas.

(e) Conventional technology and problems Figure 1 is a diagram to schematically explain the relationship between the radiation cooler mounted on a satellite and the earth, and Figure 2 is a diagram to schematically explain the relationship between the radiation cooler mounted on the artificial satellite and the earth. It is a side sectional view for explaining the structure of a guide.

As shown in FIG. 1, the radiation cooler 50 is mounted on the artificial satellite main body 2 (hereinafter referred to as satellite 2) and receives infrared rays 9 incident from the earth 1 in the direction of arrow A through a mirror 3 attached to the satellite 2. an infrared detector 4, a cooling plate 5 to which the detector 4 is attached,
An infrared guide 10 whose one end is fixed to a cooling plate 5 and formed to cover the outer periphery of the detector 4 in a cylindrical shape, and a thermal ray 8 incident from the direction of arrow B are directed to outer space 100.
It is composed of a reflecting plate 6 that reflects the light in the direction, and a shield 7 formed to cover all sides of the reflecting plate 6. Now, the cooling plate 5 of the radiation cooler 50 configured in this way is cooled by heat radiation to the outer space 100 whose environmental temperature is 4〓, and the infrared detector 4 attached to the cooling plate 5 also has an operating temperature. is
Cooled down to 100㎓. The infrared rays 9 incident through the satellite 2 and the infrared guide 10 are observed by the infrared detector 4.

Here, in the infrared guide 10, outgas 20 leaking from a heat insulating material (not shown) interposed between the reflection plate 6 and the shield plate 7 adheres to the light receiving window surface of the detector 4 and freezes. It has the role of preventing FIG. 2 is an enlarged side sectional view schematically expressing the main structure of this part, and parts equivalent to those in the previous figure are given the same reference numerals.

As is clear from FIG. 2, by providing a cylindrical guide 10 in front of the detector light receiving window 4', outgas 20 generated from the heat insulating material is prevented from going around and adhering to the light receiving window 4'. be able to. By the way, it is preferable that the inner surface of this guide 10 be mirror-finished so as not to absorb heat as much as possible, but with a mirror-finished guide structure, stray light 30 (infrared light that is a pure frame that has passed through the regular route to be observed) is It is not possible to prevent secondary reflected light (generic term for heat rays generated inside the satellite 2) from entering the detector. Therefore, a problem arises in that the reliability of the observation of infrared rays 9 by the detector 4 is impaired by the stray light 30 that enters the light receiving window 4'.

(d) Purpose of the Invention The present invention has been made to correct the above-mentioned drawbacks of the conventional technology, and includes a radiation cooling system that improves the reliability of an infrared detector by means of a stray light reflecting structure provided on the inner surface of an infrared guide. The purpose is to provide equipment.

(e) Structure of the Invention This object comprises an infrared guide 10 that guides infrared rays 9 incident through the interior of the artificial satellite main body 2 to a light receiving window 4' of an infrared detector 4, In the radiation cooler that cools the device 4 by thermal radiation into outer space 100, the infrared guide 10 includes a stray light reflection structure that reflects stray light 30 mixed with the infrared rays 9 and reflected in the direction opposite to the direction of incidence of the stray light 30. This is accomplished by providing a radiant cooler with an internal surface.

(f) Examples of the invention Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 3 is a side sectional view for explaining the structure of the infrared guide, which is a feature of the radiation cooler according to the present invention;
4A to 4D are side sectional views schematically expressing a modification of the structure of the infrared guide, and in these figures, the same parts as in the previous figure are designated by the same reference numerals. In addition, in the following explanation, parts that overlap with the explanations of FIGS. 1 and 2 will be omitted as appropriate. Since the present invention is characterized in that the inner surface of the infrared guide has a stray light reflecting structure, the description will focus on this characteristic.

FIG. 3 shows that the inner surface 10' of the cylindrical infrared guide 10 is tapered so that the cross-sectional area decreases as it approaches the satellite 2 side, and is plated with gold. This is an example of a structure in which stray light 30 (unnecessary thermal radiation) entering from the direction is reflected by two surfaces, an inner surface 10' and a bottom surface 10'', and is not allowed to enter the light receiving window 4' of the infrared detector 4,
With such a structure, the stray light 30 enters the light receiving window 4' of the infrared detector 4, and interferes with the infrared rays 9 that enter from the direction of arrow A, which is the normal route, so that the observation data by the infrared detector 4 is Phenomena that reduce reliability are improved very efficiently.

FIG. 4a shows a reflection structure for stray light 30 in which a plurality of tapered shapes similar to those shown in FIG. Yes, inner surface 10' from the direction of arrow D
The stray light 30 that has entered is emitted in the direction of arrow D' through the path explained in FIG.

In FIG. 4b, the inner surface 10' of the infrared guide 10 is formed into a "screw shape", and stray light 30 incident from the direction of arrow E is reflected on the threaded surface 101 and emitted in the direction of arrow E', and is emitted to the detector 4. This is a second modification example having a structure in which no light is incident.

FIG. 4c shows a third modification in which the inner surface 10' of the guide 10 is shaped like a bellows 102 to reflect stray light 30 incident from the direction of arrow F, reflect it again on the opposite surface, and emit it in the direction of arrow F'. Give an example.

FIG. 4d shows a detector 4 mounted on the inner surface 10' of the guide 10.
A fourth light-blocking wall 103 is provided with a plurality of light-blocking walls 103 shaped like a funnel with one side expanded and the other side contracted to reflect the stray light 30 incident from the direction of arrow G as shown in the figure and emit it in the direction of arrow G'. This is a modified example.

By configuring the inner surface 10' of the infrared guide 10 in this way, the light receiving window 4' of the infrared detector 4 is
Only the infrared rays 9 from the regular route are effectively incident on the detector 4, and the stray light 30 is emitted to the opposite side of the detector 4 while being attenuated by reflection.

(g) Effects of the Invention As explained in detail above, the radiation cooler of the present invention can accurately prevent the incidence of stray light that may interfere with the function of the infrared detector by improving the inner structure of the infrared guide that guides infrared rays to the infrared detector. It is said to be highly effective in preventing this.

[Brief explanation of the drawing]

Figure 1 is a diagram to explain the relationship between the radiation cooler and the earth, Figure 2 is a diagram to explain the conventional infrared guide equipped in the radiation cooler, and Figure 3 is the radiation cooling according to the present invention. Figures 4a to 4d are diagrams for explaining the structure of the infrared guide of the device, and diagrams for explaining modified examples of the infrared guide according to the present invention. In the drawing, 1 is the earth, 2 is the satellite itself,
3 is a mirror, 4 is an infrared detector, 4' is a light receiving window,
5 is a cooling plate, 6 is a reflector, 7 is a shield plate, 8 is a heat ray, 9 is an infrared ray, 10 is an infrared guide, 1
0' is the inner surface of the guide, 14 is the outer periphery of the light receiving window, 20
1 is an outgas, 30 is a stray light, 50 is a radiation cooler equipped with a cooling plate 5, a reflection plate 6, and a shield plate 7.
00 represents outer space, 101 represents a screw surface, 102 represents a bellows shape, and 103 represents a light blocking wall.

Claims (1)

[Scope of Claims] 1. An infrared guide 10 for guiding infrared rays 9 incident through the interior of the satellite main body 2 to a light receiving window 4' of an infrared detector 4. In the radiation cooler that cools the space 100 by heat radiation, the infrared guide 10 has a stray light reflection structure on its inner surface that reflects the stray light 30 that enters the infrared ray 9 in a direction opposite to the direction of incidence thereof. A radiation cooler characterized by: