JPH03243834A - Infrared detector - Google Patents

Abstract

PURPOSE:To allow adequate detection and IR detection in plural different frequency bands by providing an antireflection film on the vacuum side of the transmission window of an outside cylinder, the band-pass filters laminated with different refractive index materials on the front and rear surfaces of a transmission substrate, and a filter part constituting an optical window formed with a low reflectivity film on the rear surface thereof, etc. CONSTITUTION:The antireflection film 14b consisting of a material, such as Ge or Si, which does not reflect IR rays is formed on the inner side of the window 14a of the outside cylinder 14 to absorb the stray light entering from the window 14a and reflected by the surface of an inside cylinder 16. The many materials which allow the transmission of IR rays and vary in refractive index are laminated and formed on the front and rear surfaces of the substrate 40a consisting of the material to allow the transmission of the IR rays of the determined frequency band width as its base material to provide a band-pass filter function on the cold filter 40 on an IR detecting element 24; further, the optical window 40d to regulate the incident angle of IR rays is formed of the low reflectivity film 40c. The adequate detection and the detection of the IR rays of the desired frequency band width are executed in this way.

Description

[Detailed Description of the Invention] Table of Contents Prior Art Field of Industrial Application Prior Art Problems to be Solved by the Invention Means for Solving the Problems Implementation Example Outline of the Effects of the Invention Between the outer cylinder and the inner cylinder Regarding an infrared detection device that has a vacuum insulated container with a vacuum part in between, and an infrared detection element is housed in the vacuum part of the vacuum insulated container, stray light due to reflection of infrared rays on the inner surface of the outer cylinder of the vacuum insulated container is prevented. The purpose of this is to enable proper detection and to provide an infrared detection device that can detect infrared rays of multiple different frequency bandwidths with one device. A vacuum part is formed by a metal outer cylinder on which a window is formed and an inner cylinder made of a glass material with a gold vapor-deposited film formed on the surface, and an infrared sensing element is mounted and fixed on the upper surface of the inner cylinder. In the infrared detection device equipped with a heat insulating container, an anti-reflection film that does not reflect infrared rays is formed on the vacuum section side surface of the transmission window of the outer cylinder, and on the upper and lower surfaces of a substrate made of a material that transmits infrared rays in a predetermined frequency bandwidth, A filter film is formed by laminating a large number of materials that each transmit infrared rays and have different refractive indexes.
A filter section consisting of an optical window in which a low reflectance film is formed in a predetermined pattern on the lower surface of the bandpass filter is formed opposite to the light receiving section of the infrared detecting element and higher than the light receiving section. It is configured by being placed and fixed via a pedestal.

INDUSTRIAL APPLICATION FIELD The present invention relates to an infrared detection device having a vacuum insulation container having a vacuum section between an outer cylinder and an inner cylinder, and in which an infrared detection element is housed in the vacuum section of the vacuum insulation container.

Infrared sensors (infrared detection elements) can detect the presence, shape, temperature, composition, etc. of a target object without having to come into contact with it.
It is used in many fields such as geological and resource surveys and medical applications using infrared thermography. Among such infrared sensors, photoelectric conversion sensors using binary or ternary compound semiconductors have high sensitivity and fast response speed, but usually require cooling of the element to approximately the temperature of liquid nitrogen.

Therefore, an infrared detection device using such an infrared detection element is a vacuum insulated container that has a dual structure consisting of an inner cylinder and an outer cylinder, and has a vacuum section between the inner cylinder and the outer cylinder. An infrared transmission window having a bandpass filter that transmits infrared rays of a predetermined wavelength is provided at the top of the outer cylinder of the container, and an infrared detection element composed of multiple elements is installed at the top of the inner cylinder opposite to the transmission window. Set up. and,
Either a refrigerant such as liquid nitrogen is housed in the inner cylinder of the vacuum insulated container configured as described above, or a Joule-Thomson type low-temperature cooling device is installed to cool the infrared sensing element to approximately the temperature of liquid nitrogen. The configuration is such that

Furthermore, in the above-mentioned infrared detection device, infrared rays incident through the transmission window are reflected by the surfaces of the outer cylinder and the inner cylinder.
This reflected light, ie, stray light, may enter the light receiving section of the infrared detection element, making it impossible to perform proper detection. Therefore, there is a need for an infrared detection device that can suppress stray light.

Furthermore, in this type of infrared detection device, the frequency bandwidth of the infrared light that passes through the transmission window is limited by the bandpass filter, so even if multiple infrared detection elements with different detection wavelength bands are used, one infrared detection The detection device cannot detect infrared rays of multiple different wavelengths. Therefore, in order to transmit and detect infrared rays of a plurality of different wavelengths, it is necessary to prepare a plurality of infrared detection devices and equip each infrared detection device with a bandpass filter having a different frequency bandwidth. In this case, the overall size of the device to which the infrared detection device is attached must be increased accordingly. Therefore, it is desired that one infrared detection device be able to detect infrared rays of a plurality of different frequency bandwidths.

Conventional technology FIG. 5 is a schematic diagram of a conventional infrared detection device.

In this figure, 10 is a vacuum heat insulated container, which is mounted on a helium circulation cooler 12. Vacuum insulation container 10
The outer cylinder 1 includes an outer cylinder 14 made of Kovar and an inner cylinder 16 made of glass with a gold vapor-deposited film formed on the surface.
4 and the inner cylinder 16, and the outer cylinder 14,
Both inner cylinders 16 are mounted on a mounting member 18 made of Kovar, and this mounting member 18 is fixed on a support member 20 mounted on the helium circulating cooler 12. 22 is an annular ceramic substrate for taking out the lead wire 27 from the vacuum insulation container 10 to the outside, and is attached to the outer tube 14 in a sandwich manner. Further, a multi-element type infrared detection element 24 made of HgCdTe or the like is adhered to the upper end surface of the inner cylinder 16, and a cold shield 30 is fixed to the upper part of the infrared detection element 24.

As shown in FIG. 6, this cold shield 30 is adhered to the top of the infrared sensing element 24 on an annular fixing base 31 made of indium or the like, so as not to come into contact with the light receiving part 24a of the infrared sensing element 24. It's Nishide. In addition, as shown in the figure, the cold shield 30 transmits only infrared rays in a predetermined frequency band onto the upper surface of the substrate 30, 1, which is made of a transparent ZnS (zinc sulfide) material that transmits infrared wavelength region. An optical system that regulates the angle of incidence of infrared rays 35 indicated by a broken line by forming an anti-reflection film 30b made of a transparent material such as Ge (germanium) or Si (silicon) and forming a low reflectance film 30C on the lower surface of the substrate 302. A target window 30d is formed, and an antireflection film 30b' is further formed on this window 30d.

Further, the upper surface of the outer cylinder 14 is a window 14a having a bandpass filter function that transmits only infrared rays in a predetermined frequency band, and is formed of a material such as Ge or Sl.

In the above-described configuration, when the circulating cooler 12 is driven, the infrared sensing element 24 is activated via the rod 26 made of SO3 and the thermally conductive spring 28 made of copper alloy.
is cooled to approximately the temperature of liquid nitrogen, allowing infrared radiation to be detected.

Problems to be Solved by the Invention By the way, in the above-mentioned conventional infrared detection device,
Infrared rays incident through the window 14a are reflected on the surfaces of the inner cylinder 16 and the outer cylinder as shown by arrow Y, and this reflected light, that is, stray light, enters the infrared detection element 24. This stray light becomes a false signal to the infrared rays that the infrared detection element 24 receives from the subject, that is, the signal light, and therefore, as described above, when this stray light enters the infrared detection element 24, there is a problem of false detection.

Furthermore, in this infrared detection device, the frequency bandwidth of the infrared rays transmitted through the window 14a is limited by the bandpass filter, so one infrared detection device may use a plurality of infrared detection elements with different detection wavelength bands. However, it has the disadvantage that it cannot detect infrared rays in multiple different frequency bandwidths.

Furthermore, in order to detect infrared rays with multiple different frequency bandwidths, it is necessary to prepare multiple infrared detection devices and equip each with a bandpass filter that transmits only infrared rays with different frequency bandwidths. When a plurality of infrared detection devices are used in this way, a problem arises in that the device to which the infrared detection devices are attached must be made correspondingly larger.

The present invention has been made in view of these points, and it is possible to prevent stray light due to reflection of infrared rays on the inner surface of the outer cylinder of a vacuum insulated container, and thereby enable proper detection. An object of the present invention is to provide an infrared detection device capable of detecting infrared rays with a plurality of different frequency bandwidths.

Means for Solving the Problems In the present invention, a vacuum section is formed by a metal outer cylinder having a transmission window that transmits infrared rays formed on the upper surface, and an inner cylinder made of a glass material having a gold vapor-deposited film formed on the surface. In the infrared detection device, the infrared detection device is equipped with a vacuum insulation container in which an infrared detection element is mounted and fixed on the upper surface of the inner cylinder, and an antireflection film that does not reflect infrared rays is formed on the vacuum part side surface of the transmission window of the outer cylinder. .

Then, a bandpass filter is formed by laminating a large number of materials that transmit infrared rays and have different refractive indexes to form a filter film on the upper and lower surfaces of a substrate made of a material that transmits infrared rays in a predetermined frequency band. A filter section consisting of an optical window in which a low reflectance film is formed in a predetermined pattern on the lower surface of the pass filter is placed opposite to the light receiving section of the infrared sensing element, and a pedestal formed higher than the light receiving section is mounted. It is configured by placing and fixing it through the cable.

According to another aspect of the present invention, a vacuum section is formed by a metal outer cylinder having a transmission window formed on its upper surface that transmits infrared rays, and an inner cylinder made of a glass material having a gold vapor-deposited film formed on its surface. In the infrared detection device, the infrared detection device is equipped with a vacuum insulation container in which an infrared detection element is mounted and fixed on the upper surface of the inner cylinder, and an antireflection film that does not reflect infrared rays is formed on the vacuum part side surface of the transmission window of the outer cylinder. . Then, a hard material that does not transmit infrared rays in a predetermined frequency band width is formed to a predetermined thickness by anisotropic etching, and a first member and a second member are formed with through holes of a predetermined size at predetermined positions. It consists of parts and a bandpass filter in which a filter film is formed by laminating a large number of materials that transmit infrared rays and have different refractive indexes on the upper and lower surfaces of a substrate made of materials that transmit infrared rays in a predetermined frequency bandwidth. The filter section is mounted and fixed on the infrared detecting element so that the through hole is located above the light receiving section.

Furthermore, it is also possible to adopt a configuration in which a plurality of infrared detection elements are mounted on the inner cylinder and a filter section is provided on each infrared detection element.

Function According to the present invention, an anti-reflection film that does not reflect infrared rays is formed on the vacuum part side surface of the transmission window of the outer cylinder, and a band-pass filter that transmits infrared rays in a predetermined frequency bandwidth and a low-reflection film are formed. A filter section consisting of an optical window formed by forming a filter film in a predetermined pattern is placed and fixed on a pedestal formed higher than the light receiving section of the infrared sensing element, facing the light receiving section. .

Therefore, stray light that enters through the transmission window and is reflected on the surface of the inner cylinder is not reflected on the surface of the outer cylinder, so that no stray light enters the infrared detecting element. This eliminates false detection due to stray light and allows proper detection.

In addition, the incident angle of infrared rays is regulated by the optical window,
Furthermore, infrared rays having a predetermined frequency bandwidth are transmitted through the bandpass filter and are incident on the infrared detection element, so that infrared rays having a desired frequency bandwidth can be detected.

According to another aspect of the present invention, the filter section is formed by a micro part made of a hard material in which a through hole of a predetermined size is formed and which does not transmit infrared rays of a predetermined frequency bandwidth, and a band pass filter, This filter section is placed and fixed on the infrared detection element, and the through hole regulates the incident angle of the infrared rays, so even if external factors such as temperature and humidity change, the set position of the through hole remains unchanged. never changes. This allows the viewing angle of the infrared sensing element to be properly regulated.

In addition, when multiple infrared detection elements are mounted on the inner cylinder and a filter section is individually provided on each infrared detection element, the frequency bandwidth of the bandpass filter of each filter section can be adjusted for each infrared detection element. By making it correspond to the detection wavelength band of the element, it is possible to detect infrared rays in a plurality of frequency band widths.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing the configuration of an infrared detection device according to a first embodiment of the present invention. In this figure, parts corresponding to those of the conventional example shown in FIG. 5 are given the same reference numerals, and their explanations will be omitted.

The infrared detection device according to the first embodiment is different from the conventional one shown in FIG. The bandpass filter function is removed from the window 14a, and an antireflection film 14b made of a material such as Ge or S which does not reflect infrared rays is formed inside the window 14a.

That is, as shown in FIG. 2, the cold filter 40 includes a bandpass filter 41 and a bandpass filter 41.
A low reflectance film 40C formed in a predetermined pattern on the lower surface of the reflectance film 40C.

The bandpass filter 41 includes a substrate 40H made of a material such as Ge that transmits infrared rays in a predetermined frequency bandwidth.
A large number of materials that transmit infrared rays and have different refractive indexes are laminated on the upper and lower surfaces of the filter films 40b and 4.
0b' is formed. In addition, the low reflectance film 40c
is formed in a predetermined pattern, thereby forming an optical window 40d in a portion facing the light receiving portion 24a, as shown in the figure. And, with this optical window 40d,
The angle of incidence of infrared rays 35 indicated by a broken line is regulated.

According to this configuration, since the anti-reflection film 14b is formed on the window 14a of the outer cylinder 14, stray light that enters through the window 14a and is reflected on the surface of the inner cylinder 16 is absorbed by the anti-reflection film 14b. . Therefore, stray light is no longer incident on the infrared detection element 24 as in the conventional case, thereby eliminating false detection due to stray light.

In addition, the cold filter 40 on the infrared detection element 24 has a bandpass filter function, and furthermore, as in the conventional case,
Since the optical window 40d that regulates the incident angle of the infrared rays 35 is formed by the low reflectance film 40C, only infrared rays having a predetermined frequency band can be made to enter the light receiving portion of the infrared detecting element 24.

Next, a second embodiment of the present invention will be described with reference to FIG.

The difference between this second embodiment and the first embodiment shown in FIGS. 1 and 2 is that, as shown in FIG.
This was expressed through the following.

The bandpass filter 51 includes a substrate 51a made of a material such as Ge that transmits infrared rays in a predetermined frequency bandwidth.
A large number of materials that transmit infrared rays and have different refractive indexes are laminated on the upper and lower surfaces of the filter films 51b and 5.
1b'.

Further, the micro parts 52 are formed by molding a material such as Si into a predetermined shape by anisotropic etching, which takes advantage of the fact that the physical properties of substances differ depending on the direction. That is, as shown in the figure, an opening 52a is formed to a predetermined thickness by etching and has a predetermined shape at a predetermined position.
An annular first Si member 52a in the shape of an H is provided. Furthermore, by the same etching, a second annular opening 52bH, which has a predetermined thickness and has an opening 52bH shown by a broken line that regulates the incident angle of the infrared rays 35, is formed in the part facing the light receiving part 24a.
A Si member 52b is provided, and these first and second Si members 52a, 52b are bonded vertically. Then, this micropart 52 is interposed between the infrared detection element 24 and the bandpass filter 51.

In this way, since the micro-pun 52 is made of hard X, the distance between the infrared detection element 24 and the bandpass filter 51 will not change even if external factors such as temperature and humidity change. Therefore, once the angle of incidence of the infrared rays 35 that passes through the bandpass filter 51 is set, its accuracy can be guaranteed for a long time.

Next, a third embodiment of the present invention will be described with reference to FIG.

In this third embodiment, infrared detection elements 24 and 24' having different detection wavelength bands are installed on the inner cylinder 16.

The cold filters 40 (50) fixed on these infrared detecting elements 24, 24' have the configuration shown in the second embodiment or the second embodiment, and either one may be used, but each cold filter It is assumed that the bandpass filters constituting the filter transmit infrared rays having different frequency bandwidths. That is, each infrared sensing element 24.
24' detection wavelength band.

According to such a configuration, each infrared sensing element 24.24
Since it is possible to detect infrared rays with a predetermined frequency bandwidth for each ', it is possible to detect infrared rays with different frequency bandwidths using ↓ infrared detection devices.

Further, in this example, two infrared sensing elements 24.24' are installed on the inner cylinder 16, but there are many elements 24.24' that can be physically mounted. ... may be installed.

As described in detail, the present invention has the following effects.

That is, since stray light that enters through the transmission window and is reflected on the inner cylinder surface is not reflected on the outer cylinder surface, no stray light enters the infrared detection element. This eliminates erroneous detection due to stray light and allows for proper detection.

In addition, the incident angle of infrared rays is regulated by the optical window,
Furthermore, since infrared rays with a frequency bandwidth determined by the bandpass filter are transmitted and incident on the infrared detection element, there is an effect that infrared rays with a desired frequency bandwidth can be detected.

Further, according to the present invention, which utilizes micro parts made of hard materials, the set position of the through hole does not change even if external factors such as temperature and humidity change. This allows the angle of incidence of infrared rays to be regulated correctly, and once the angle of incidence of infrared rays is set, the accuracy can be guaranteed for a long time.

Furthermore, if a plurality of infrared detection elements are mounted on the inner cylinder, and the frequency bandwidth of the bandpass filter of the filter section provided on each infrared detection element is made to correspond to the detection wavelength band of each infrared detection element, This has the advantage that one infrared detection device can detect infrared rays of multiple frequency bandwidths.

This eliminates the need to use multiple infrared detectors to detect infrared rays with different frequency bandwidths as in the past, and has the effect of making it possible to reduce the size of the entire device configured by installing infrared detectors. Furthermore, by making the device smaller, manufacturing costs can be reduced.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram of an infrared detecting device according to an embodiment of the present invention, Fig. 2 is an enlarged view of a cold filter of an infrared detecting device according to a second embodiment of the present invention, and its neighboring parts; An enlarged view of a cold filter of an infrared detection device according to a second embodiment of the present invention and its surrounding parts; FIG. 4 is a diagram for explaining an infrared detection device according to a third embodiment of the present invention; FIG. 5 6 is a schematic configuration diagram of a conventional infrared detection device, and FIG. 6 is an enlarged view of the cold shield of the infrared detection device shown in FIG. 5 and its neighboring parts. 0...Vacuum insulation container, 4...Outer tube 4a...Transmission window, 4b...Anti-reflection film, 6...Inner tube, 4...Infrared detection element, 4a...Light receiving part , 0.50...Filter part, 1.51...Band pass filter, Qa, 51a...Substrate, Ob, 40b' 51b, 51b'...Filter film, C...Low reflectance film , d...Optical window,...Micro parts, aH, 52bH-...Through hole, a...First member, b...Second member. 40゜40b, 40b' 0c 0d 1 1 Substrate filter H odor 4 anti-body 4 service 1 light cloud [white] guji Venus band pass filter 2nd figure 0 ~ dimension ψ ~ one voice ~ 211-

Claims (1)

[Claims] 1. A metal outer cylinder (14) with a transmission window (14a) that transmits infrared rays formed on the upper surface, and an inner cylinder (16) made of glass material with a gold vapor-deposited film formed on its surface. In the infrared detection device comprising a vacuum insulation container (10) in which a vacuum part is formed by and an infrared detection element (24) is placed and fixed on the upper surface of the inner cylinder (16), the outer cylinder (14) An antireflection film (14b) that does not reflect infrared rays is formed on the vacuum part side surface of the transmission window (14a), and a substrate (4) made of a material that transmits infrared rays in a predetermined frequency bandwidth is formed.
A filter film (40
b, 40b') forming a bandpass filter (41)
And an optical window (40) with a low reflectance film (40c) formed in a predetermined pattern on the lower surface of this bandpass filter (41).
d) through a pedestal (31) formed higher than the light receiving part (24a) of the infrared detecting element (24). An infrared detection device characterized in that it is mounted and fixed. 2. A vacuum section is formed by a metal outer cylinder (14) with a transmission window (14a) formed on the top surface that transmits infrared rays, and an inner cylinder (16) made of glass material with a gold vapor-deposited film formed on its surface. In the infrared detection device comprising a vacuum insulation container (10) in which an infrared detection element (24) is placed and fixed on the upper surface of the inner cylinder (16), the transmitting window (14a) of the outer cylinder (14) An anti-reflection film (14b) that does not reflect infrared rays is formed on the vacuum part side surface, and a hard material that does not transmit infrared rays in a predetermined frequency band is formed to a predetermined thickness by anisotropic etching, and a predetermined size is formed at a predetermined position. A micro part (52) consisting of a first member (52a) and a second member (52b) in which through-holes (52aH, 52bH) are formed, and a substrate (51a) made of a material that transmits infrared rays in a predetermined frequency bandwidth. A filter section (50) consisting of a bandpass filter (51) formed on the upper and lower surfaces of which filter films (51b, 51b') are formed by laminating a large number of materials that transmit infrared rays and have different refractive indexes. The through holes (52aH, 52b) are formed above the light receiving part (24a).
An infrared detecting device, characterized in that the infrared detecting element (24) is mounted and fixed so that the infrared detecting element (24) is located at the position indicated by H). 3. In the infrared detection device according to claim 1 or 2, a plurality of infrared detection elements (24) are mounted on the inner cylinder (16), and a filter section is provided on each infrared detection element (24). An infrared detection device characterized by mounting and fixing (40, 50).