JPS60253538A - Thermal-shield - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention relates to a thermal shield,
In particular, it relates to a thermal φ shield used for thermal control of an artificial satellite.

[Conventional technology]

Figure 1 shows a conventional thermal shield of this type. In Figure 1, a fluoroethylene-propylene copolymer (F
EP), a metal film made of vapor deposition of silver, aluminum, etc. is formed on the back side of a transparent polymer film l made of a polymer such as polyimide or polyethylene terephthalate, and this metal film is used to provide anis grounding to the satellite structure. Ta.

The thermal shield with the above configuration is attached to the surface of the satellite and has the function of keeping the onboard equipment inside the satellite within the appropriate permissible temperature range, but it depends on the solar absorption rate of the thermal shield. and passively by infrared emissivity. The solar absorption rate is determined by the ability of the metal film λ to reflect sunlight that has passed through the transparent polymer film l, and the infrared emissivity is determined by the ability of the metal film λ to reflect sunlight that has passed through the transparent polymer film l. It is determined by the property of radiation. This emissivity is generally increased in many cases by increasing the thickness of the transparent polymer film l by jOμIfl−/
, about 27 μm.

However, as described above, conventional thermal shields are relatively buried and the transparent polymer film is exposed to the space side, so it is charged by space plasma, especially electrons, and sometimes a large potential difference is created between the surface and the satellite. Discharge may occur between the transparent polymer film l and the earth, and this phenomenon occurs when the transparent polymer film
It is large in the case of EP and polyethylene terephthalate. In that case, there was a drawback that the electronic equipment onboard the satellite could malfunction or break down.

[Summary of the invention]

This invention was made to eliminate the above-mentioned drawbacks of the conventional products.A thin transparent polyimide film is pasted on the surface of a transparent polymer film using a conductive adhesive to prevent the surface from being charged. Thermal
Provide a shield.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. 2, in which the same parts as in FIG. 1 are denoted by the same reference numerals.

In FIG. 2, a transparent polyimide film J and a transparent polymer film I are bonded together using a transparent conductive adhesive V. Both the conductive adhesive layer and the metal film λ are grounded to the satellite structure.

Next, the effect will be explained. In the Ramamal shield configured as described above, the transparent polyimide film 3 is exposed to the space side.

The surface of the transparent polyemide film J is charged by charged particles of space plasma that have such energy that they do not pass through it, forming a potential. However, there is a layer of transparent conductive adhesive on the back side of the transparent polyimide film 3, and this is grounded to the satellite structure, so the internal potential of the thin transparent polyimide film J due to the potential on the first surface becomes a transverse potential gradient. , the conductivity becomes sharp. At this time,
The current flowing inside the transparent polyimide film 3 increases, and in an equilibrium state, the surface potential does not reach a level that would cause a discharge. In Figure 3, 0 m1J (127 μm)
Then, an electron beam was applied to a transparent polyimide film J with a thickness of ymtj (7 aμR) at 10 Key, 0.7 n A/
Polyimide film 3 when irradiated under CD irradiation conditions
The time characteristics of the current flowing through the polyimide film 3 are shown, and it shows that the thinner the polyimide film 3 is, the better the current flows and the less likely it is to be charged.

The energy of charged particles in space plasma is 9V in steady state near geostationary orbit, and ~20K in geomagnetic winds.
eV, so that the thickness of the transparent polyimide film 3 must be approximately 0.3 ml (tA μm) or less so that there is no effect of charging and accompanying discharge during magnetic wind. Plasma in the universe consists of several e of electrons.
Since there are energies ranging from as low as V to as high as several tens of MevO, they may penetrate the layer of the thin transparent polyimide film 3 and accumulate in the transparent polymer film 1.
Alternatively, the layer of transparent polymer film 1 may also be penetrated. However, these are very few compared to the number of particles accumulated in the transparent polyimide film 3, and
Even if the charge is accumulated in the layer of the transparent polymer film 1, the amount of charge is small, and since both ends of the transparent polymer film are grounded, no discharge occurs.

In the above embodiment, the transparent polyimide film 3 was also attached to the surface of the transparent polymer film 1 using a transparent conductive adhesive. may be attached to the transparent polymer film 1 using a conductive adhesive. Its configuration is shown in Figure d. That is, a metal M is formed on a polyimide film 3 by vapor deposition, and the surface of the metal film S and the surface of the transparent polymer film 1 are bonded together using a conductive adhesive. In this case, although the sunlight absorption rate is reduced by the amount of the metal film 5, the same effect can be achieved.

〔Effect of the invention〕

As described above, according to the present invention, since a thin transparent polyimide film is attached to the surface of a transparent island molecular film using a conductive adhesive, charging can be prevented and the effects of discharge can be removed, thereby improving reliability. This has the effect of making it possible to construct a satellite system with high performance.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a conventional product, Fig. 2 is a cross-sectional view of an embodiment of the present invention, and Fig. 3 is a time period of the M flow flowing through the polyimide film when the polyimide film is irradiated with an electron beam in this embodiment. Characteristic fee! Figures 1 and q are cross-sectional views of other embodiments of the present invention. /...Transparent polymer film, Co...Vapour-deposited gold R film, J...
Transparent polyimide film, transparent conductive. adhesive, j...metal film. In each figure, the same reference numerals indicate the same or corresponding parts. Ahead 3 figures Death 4 figures

Claims (1)

[Claims] (1) A thermal film comprising a transparent polymer film with a vapor-deposited metal film formed on the back surface and a transparent polyimide film bonded to the surface of the transparent polymer film with a transparent conductive adhesive. shield. (J) The thermal shield according to claim 1, wherein the transparent polymeric film is made of a polymeric material selected from fluoroethylene-propylene copolymer (FEP), polyimide, and polyethylene terephthalate. (3) Thickness is 0. ! 2. The thermal shield of claim 1, comprising a transparent polyimide film not exceeding r mij. (i) The thermal film according to claim 1, comprising a transparent polyimide film with a metal film deposited on the adhesive surface.
Sealed.