JPH058445U - Infrared optical system - Google Patents

Abstract

(57) [Summary] [Objective] To obtain an infrared optical system that can use a small cooler. A black mask plate 9a having the same opening size as the cold shield 5a is provided between the lens 1 and the window 3, and the outer surface of the cold shield 5a is mirror-finished. By making the outer surface of the cold shield 5a a mirror surface, the amount of heat intrusion due to infrared radiation of the cold shield 5a can be suppressed.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

  This invention relates to the configuration of an infrared optical system for forming an infrared image. .

[0002]

[Prior art]

  FIG. 3 is a sectional view showing a conventional infrared optical system. 1 is the lens, 2 is the figure Dewar with a vacuum inside, 3 is a window fixed to Dewar 2, and 4 is an infrared detector. Intelligence 5 is a cold shield attached to the infrared detector 4 by being thermally coupled, 6 is a wire for electrically connecting to the infrared detector 4, 7 is a hermetic terminal, 8 is infrared detection It is a cooler for cooling the container 4.

[0003]   The conventional infrared optical system is configured as described above and operates as follows. Len An infrared detector 4 is arranged on the image plane of the pixel 1. The infrared detector 4 is, for example, platinum. ・ Silicon Schottky barrier type two-dimensional solid-state image sensor with drive signal and output signal Infrared detection by connecting the signal to the outside via wire 6 and airtight terminal 7. The infrared image formed on the container 4 is output to the outside as an electric signal. Cooler 8 is red It has the function of cooling the outside line detector 4 to a proper extremely low temperature (about 80K), The dewar 2 held in a vacuum reduces the amount of heat that enters the infrared detector 4, The cooling capacity of LA8 is small.

[0004]   The cold shield 5 is made of metal with thermal conductivity, and this temperature is red. By making the cryogenic temperature almost equal to that of the outside line detector 4, the outside of the optical path of the lens 1 is The infrared rays of the infrared detector 4 are shielded, and the noise of the infrared detector 4 which may be caused thereby is removed. There is an action. Also, the inside and outside surfaces of the cold shield 5 are treated with black. The reason is that stray light due to reflection due to this is attenuated.

[0005]

[Problems to be solved by the device]   In the conventional infrared optical system as described above, the outer surface of the cold shield 5 is It should be black, that is, the surface with high absorption rate, Large amount of heat penetration by infrared radiation passing through 3 and entering cold shield 5 . Therefore, it is necessary to use a large capacity for the cooler 8. Since it is necessary to use a large one, it is inevitable that the device will be large. There was a problem.

[0006]   This invention was made in order to solve such a problem. To reduce the amount of heat entering the field 5 and to reduce the demand for the capacity of the cooler 8. Therefore, it is intended to realize a small infrared optical system.

[0007]

[Means for Solving the Problems]

  In the infrared optical system according to the present invention, the cold is placed between the lens and the window. Provide a black mask plate with the same opening as the shield opening size, and It is mirror-finished.

[0008]   Further, in the infrared optical system according to this invention, a lens is provided between the lens and the window. Install a black mask plate with an opening larger than the The area outside the mask plate that is larger than the opening size of the mask plate is black, and the remaining area is a mirror. It is surface processed.

[0009]

[Action]

  The infrared optical system configured as described above makes the outer surface of the cold shield a mirror surface. Therefore, the infrared absorption rate of the cold shield becomes small.

[0010]

【Example】

Example 1.   FIG. 1 is a sectional view showing an embodiment of the present invention, in which 1 to 4 and 6 to 8 are the above-mentioned conventional devices. It is exactly the same as the table. 5a is a cold sea with black inside and mirror outside , 9a is a black mask having an opening of the same size as the opening of the cold shield 5a. It is a plate.

[0011]   In the infrared optical system configured as described above, the cold shield 5a Since the outside is a mirror surface, the absorption rate of the cold shield 5a is small, and therefore the amount of heat penetration Is small. Also, when observing the direction of the mask plate 9a from the lens 1 side, the entire surface is black. Therefore, an infrared optical system with little stray light can be realized.

[0012] Example 2.   FIG. 2 is a sectional view showing another embodiment of the present invention, in which 1 to 4 and 6 to 8 are the conventional ones. It is exactly the same as the device. 5b is a cold seal with black inside and mirror outside A black part is provided in the field. 9b is the opening size of the cold shield 5b A black mask plate 10 having a larger opening is a black portion.

[0013]   In the infrared optical system configured as described above, the cold shield 5b The amount of heat penetration is small because the outside is a mirror surface, but there is a black portion 11 Compared to Example 1, the amount of heat penetration is slightly larger. On the one hand, the opening edge of the mask plate 9b Is in the area of the black portion 10, the accuracy of the opening dimension of the mask plate 9b and the mass There is a feature that the mounting accuracy of the black plate 9b may be poor.

[0014]

[Effect of device]

  Since the present invention is constructed as described above, Have an effect.

[0015]   By making the outer surface of the cold shield a mirror surface, infrared rays to the cold shield can be obtained. It is possible to suppress the amount of heat penetration due to the line radiation.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a sectional view showing a second embodiment of the present invention.

FIG. 3 is a sectional view showing a conventional infrared optical system.

[Explanation of symbols]

1 lens 2 Dewa 3 wind 4 infrared detector 5 cold shield 5a cold shield 5b cold shield 6 wires 7 Airtight terminal 8 cooler 9a mask plate 9b Mask plate 10 Black part

Claims (2)

[Scope of utility model registration request] 1. An infrared optical system for forming an infrared image on an infrared detector, a lens, a dewar having a window for transmitting infrared rays, and a dewar provided in the dewar at an image forming position of the lens. An infrared detector arranged, a cold shield arranged between the window and the infrared detector, and an opening having the same size as the opening of the cold shield provided between the lens and the window. An infrared optical system comprising a black mask plate and a mirror-finished outer surface of the cold shield. 2. An infrared optical system for forming an infrared image on an infrared detector, a dewar having a lens and a window for transmitting infrared rays, and a dewar provided in the dewar and arranged at an image forming position of the lens. Black mask having an aperture larger than the aperture size of the cold shield provided between the lens and the window, a cold shield disposed between the window and the infrared detector, and An infrared optical system, comprising: a plate, and a portion of the outer surface of the cold shield, which is larger than the opening size of the black mask plate, remaining black.