JPH0212552Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a radiation cooler for an infrared detector mounted on a geostationary satellite.

[Conventional technology]

Conventional coolers of this type include radiation coolers used in visible infrared radiometers (VISSR) aboard geostationary meteorological satellites 1 to 3, as shown in FIGS. 2A and 2B.
When designing a radiation cooler, there are two conditions to be met: (1) sunlight should not be directly incident on the surface to be cooled, and (2) the surface to be cooled should not look directly at a surface at room temperature. It's summery.

To explain the VISSR radiation cooler, in Figure 2 A and B, the solar shield 1 with a small infrared emissivity ε for cutting off sunlight 6 is at room temperature, so the infrared rays with a high infrared emissivity ε are detected. It was necessary to prevent the dexterity cooling surface 4 (having the infrared detector 5) from directly viewing the shield 1. For this purpose, it was necessary to provide a cooled cone 3 with a small infrared emissivity ε between them, and to provide an intermediate cooling surface 2 with a high infrared emissivity ε for cooling the cone 3.

[Problems to be solved]

From the above, the conventional radiation cooler requires at least four types of surfaces, including the infrared detector cooling surface 4, and the overall size is quite large.

In other words, the maximum external diameter of VISSR's radiation cooler is 450mm.
φ, and the detector 5 with a calorific value of 2 mw can be cooled to 80 k. With this method, the heat output is 100mw
In order to cool the detector 5 to 80K, a maximum external diameter of 3 mφ was required, which caused the problem that it was too large to be mounted on a satellite.

[Means for solving problems]

This invention solves the above problems,
an infrared detector cooling surface having an infrared detector;
A solar shield provided at a predetermined opening angle on the outer periphery of the cooling surface and having a low absorption rate in the visible range and a low emissivity in the infrared range; It consists of an intermediate cooling surface that has been subjected to a high emissivity surface treatment.

〔Example〕

Next, the embodiment will be explained with reference to FIGS. 1A and 1B.

FIGS. 1A and 1B are a plan view and a vertical sectional view, respectively, of an embodiment of a radiation cooler according to the present invention, and in each figure,
The same parts as in FIGS. 2A and B are given the same reference numerals.

In the figure, compared to the radiation cooler in Figure 2, the radiation cooler removes the conventional solar shield 1 and replaces the conventional cone 3 with a solar absorption rate α in the visible range.
The solar shield 3-1 is used as a substitute for the solar shield 3-1, which has a small radiation rate and a low emissivity ε in the infrared region, and the opening angle is changed so that it also serves as a solar shield, and the surface of the intermediate cooling surface 2-1 has a solar absorption rate. The surface is treated with a secondary mirror surface having a small α and a high infrared emissivity ε.

The sunlight 6 enters the sunlight shield 3-1 and the intermediate cooling surface 2-1, and is reflected to outer space at most once. Further, the solar shield 3-1 is cooled by the intermediate cooling surface 2-1 which has been subjected to a surface treatment with a high emissivity ε. The heat generated by the infrared detector 5 becomes heat rays emitted from the infrared detector cooling surface 4, and is emitted into space after being reflected at most once on the solar shield 3-1.

This structure eliminates the need for the normal-temperature solar shield 1 that was present in conventional radiation coolers, making it possible to downsize.

Based on the above concept, the maximum outer diameter of the radiation cooler for cooling the detector 5 with a heat output of 100 mw to 80 k is 1.2 mφ. As a result, we produced a prototype as a 1/4 scaled model and confirmed its performance.

〔effect〕

As explained above, the present invention removes the room-temperature sunlight shield for cutting sunlight, uses a cone instead as a sunlight shield, and further includes two steps in the surface treatment of the cooling surface that cools the shield.
Since it uses a second mirror surface, it has the advantage of being able to downsize the entire device without a conventional solar shield, and can also be used in cases where the detector generates a large amount of heat, such as in conventional weather satellites. .

[Brief explanation of the drawing]

Figures 1A and B are a plan view and a vertical sectional view of an embodiment of a radiation cooler according to the present invention, respectively, and Figures 2A and B are
1 is a plan view and a longitudinal sectional view of a conventional radiation cooler. 1, 3-1...Solar shield, 2, 2-1...
... Intermediate cooling surface, 3 ... Cone, 4 ... Cooling surface for infrared detector, 5 ... Infrared detector, 6 ... Sunlight.

Claims (1)

[Scope of utility model registration request] A cooling surface for an infrared detector having an infrared detector, a solar shield provided at a predetermined opening angle on the outer periphery of the cooling surface and having a low absorption rate in the visible range and a low emissivity in the infrared range, and a solar shield provided on the outer periphery of the solar shield. A radiation cooler consisting of an intermediate cooling surface that has been provided with a surface treatment that has low absorption in the visible range and high emissivity in the infrared range.