JPS60253928A - Cold shield - Google Patents

Abstract

PURPOSE:To reduce loss due to heat radiation and prevent even stray light due to irregular reflection by using Al for the cold shield which specifies the visual field angle of an infrared-ray detecting element, and forming the internal surface of a constitution body into a specular surface with metallic luster and the internal surface into a dull surface through an alumite blackening treatment. CONSTITUTION:The cold shield 3 which specifies the visual field angle of the infrared-ray detecting element 6 is made of Al; its external surface O is made into specular surface and covered and protected wih wax, resist, etc., to have an about 1 reflection factor, and the internal surface I is formed by the alumite treatment to obtain a nearly 0 reflection factor. Thus, the loss due to heat radiation between the cold shield 3 and the external cylinder 4 of the container and stray light 7 due to irregular reflection is prevented. Consequently, the lightweight cold shield which is easily worked is easily realized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cold shield, and particularly to a cold shield that defines the viewing angle of an infrared sensing element.

[Conventional technology]

Conventional cold shields are mainly made of copper, and the entire surface of the structure is oxidized and blackened.

In this configuration, the inner and outer surfaces of the cold shield are simultaneously
Since the outer surface of the cold shield is blackened and heat is conducted by thermal radiation, there is a drawback that the cooling effect is reduced. Further, in the blackening treatment by oxidation, the reflectance does not become zero, and stray light due to diffuse reflection within the cold shield enters the sensing element, impairing the element performance. This song had disadvantages such as poor workability of copper wire) and heavy weight.

[Problem that the invention seeks to solve]

The present invention improves the above-mentioned drawbacks and provides a cold seal under which loss due to thermal radiation is small and stray light due to diffused reflection C2 is also small.

[Means for solving problems]

The present invention comprises a cold shield made of aluminum,
The outer surface of the aluminum structure is a mirror surface with metallic luster, and the inner surface of the aluminum structure on the element side is a matte surface treated with black alumite.

[Effect]

The metallic glossy surface of aluminum has a reflectance of approximately 1,
On the other hand, since the reflectance of a matte surface treated with alumite blackening is almost 0, the cold shield of the present invention can be configured with low loss due to thermal radiation and low stray light due to diffused reflection.

〔Example〕

FIG. 1 shows an embodiment of the present invention. The figure shows a cross section of a packaging container for an infrared sensing element. 2 is an infrared transmitting window, 4 is a container outer cylinder, 1 is a cold filter, and 6 is a cold shield of the present invention.

A detection element 6 is attached to the upper surface of the inner cylinder 5 of the container. The container is usually sealed between the outer container (4) and the container cylinder (5), and is evacuated to prevent heat transfer due to convection.

The inner surfaces of the container inner cylinder and outer cylinders 4 and 5 (specially (24)) are silver plated or aluminum vapor-deposited (2) to increase reflectance and prevent heat conduction due to heat radiation.Detection The element 6 is operated by cooling the inner cylinder part of the container 5 with a cryogen (for example, liquid nitrogen), etc. The cold shield of the present invention (B) is made of aluminum, the outer surface O is a mirror surface, and the inner surface I is anodized black. The loss due to thermal radiation between the cold shield 3 and the container outer cylinder 4 is small, and stray light due to diffused reflection as shown in 7 can also be prevented. , or by selectively blackening the inner surface I by covering it with a resist or the like, it can be easily realized, is easy to process, and is light in weight.

FIG. 2 shows another embodiment, in which the cold shield is constructed by combining two components C1 and C2. The numbers for each part are the same as in FIG. 1 above, and in this example, the cold shield C2+2 is the part 1 surrounded by C1. Even if there are two, it is necessary to anodize it black because it will be inside the cold shield. And, I,,I,also has an alumite blackened surface,0I,0
．． is a mirror surface with metallic luster.

〔Effect of the invention〕

According to the present invention, loss due to thermal radiation is small, stray light due to internal diffuse reflection can be prevented, and furthermore, it is possible to realize a lightweight cold shield that is easy to process.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a mounting container using an embodiment of the cold shield of the present invention, and FIG. 2 is a cross-sectional view of a mounting container using an embodiment of the cold shield pond of the present invention. (Main symbols) 1...Cold filter 2...Infrared transmission window 5...Cold shield 4...Container outer tube 5...Container, inner tube 6...Detection element 7... Stray light C1, C2...Cold shield patent applicant Fujitsu Limited agent Patent attorney Gobe Tamamushi (1 other person) Figure 1 Figure 2

Claims (1)

[Claims] In the cold shield that defines the viewing angle of the infrared detection element, the cold shield is made of aluminum,
A cold shield characterized in that the outer surface of the aluminum structure is a mirror surface with metallic luster, and the inner surface of the aluminum structure on the element side is a matte surface subjected to an alumite blackening treatment.