JPH08222746A - Infrared ray detecting element - Google Patents

Abstract

PURPOSE: To provide an infrared ray detecting element capable of cutting down the cooling cost, the price and the cost of the miniaturization of an infrared ray detector. CONSTITUTION: An infrared ray detecting element 11 composed of an infrared ray detecting part 13 on a sapphire substrate 12 and signal processing circuits 14 near both side parts of this detecting part 13 is provided with an infrared ray transmission window 16 on the position corresponding to this detecting part 13. Besides, a cold shield 15 integrally providing plural legs 18 having fixing parts 19 abutting against the near corner parts of the sapphire substrate 12 striding over the signal processing circuits 14 is fixed on the shield main body 17 covering the whole body of the infrared ray detecting part at the fixing parts 19 using screws 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared ray detecting element having a plurality of pixels on an sapphire substrate and a signal processing circuit provided adjacent to the infrared ray receiving section.

A crystal block made of a multi-element semiconductor having a small energy gap, such as mercury, cadmium, or tellurium, is provided on a sapphire substrate, a pair of contact electrodes are formed on both sides of the main surface of the crystal block, and an area between the electrodes is irradiated with infrared rays. There is known an infrared detecting element having a light receiving section and a signal processing circuit provided adjacent to the infrared receiving section. This type of infrared detecting element is generally used in a state of being cooled to a liquid nitrogen temperature (77K).

Further, in an infrared detector adopting this type of infrared detecting element, in order to increase its detection sensitivity, the viewing angle of infrared rays incident on the infrared receiving section from the object to be detected is restricted to detect the object to be detected. It is necessary to eliminate the extra radiation coming from other backgrounds. Therefore, in order to limit the viewing angle, a cold shield having an infrared transmitting window for determining the visual field is arranged on the front surface of the infrared receiving section. The cold shield is cooled together with the infrared detecting element so that it does not become a source of unnecessary light.

In an infrared detector having such an infrared detecting element, there is a demand for reducing the burden associated with cooling, lowering the cost and reducing the size.

[0005]

2. Description of the Related Art FIG. 5 is a diagram showing a prior art. In the figure, reference numeral 1 is an infrared detecting element adopting an indirect hybrid system, and the infrared detecting element 1 is a sapphire substrate 2
An infrared light receiving portion 3 having a plurality of pixels is provided in the vicinity of the central portion of, and signal processing Si circuits 4 are provided in the vicinity of both ends of the infrared light receiving portion 3.

The infrared detecting element 1 is fixed to a cooling head of a cooling means (not shown). Then, the cold shield 5 for limiting the viewing angle of the incident infrared rays to the infrared light receiving section 3 is arranged so that the infrared transmitting window 6 is positioned so as to face the infrared light receiving section 3, and It is fixed to the cooling head so as to cover it.

[0007]

However, according to the prior art, even in an infrared detecting element adopting an indirect hybrid system or the like, the infrared receiving section occupies only a part of the area of the infrared detecting element. Since a relatively large cold shield is used to cover the entire infrared detection element, the heat capacity is large, and if an infrared detector is constructed using such an infrared detection element, the cooling load by the cooling means However, there is a problem in that it is difficult to reduce the price and size.

Further, since the cold shield is directly fixed on the cooling head, when these are mounted on the cooling head to form an infrared detector, an infrared receiving portion of the infrared detecting element and an infrared transmitting window of the cold shield are provided. There is also a problem in that it is necessary to adjust the relative positional relationship between the and, and that adjustment is difficult.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an infrared detecting element capable of reducing the cooling load of the infrared detector, reducing the cost, and downsizing. To do.

[0010]

An infrared sensing element of the present invention is an infrared sensing device comprising an infrared light receiving portion having a plurality of pixels and a signal processing circuit provided adjacent to the infrared light receiving portion on a sapphire substrate. In the element, an infrared transmitting window is provided at a position corresponding to the infrared light receiving portion, and a shield main body that covers the entire infrared light receiving portion that limits the viewing angle of the infrared light receiving portion is provided across the circuit for signal processing. A cold shield integrally provided with a plurality of legs having fixing portions that come into contact with the vicinity of a corner of the sapphire substrate is integrally fixed to the sapphire substrate by the fixing portions.

[0011]

According to the infrared detecting element of the present invention, the cold shield has the shield body covering the infrared receiving portion fixed to the sapphire substrate at the fixing portion at the tip of the leg. As a result, the heat capacity can be reduced, so that the burden of cooling the infrared detector equipped with this infrared detector by the cooling means can be reduced, and the cost and size of the infrared detector can be reduced. it can.

Further, since the cold shield is fixed to the sapphire substrate, it is not necessary to adjust the positional relationship between the cold shield and the infrared light receiving portion when mounting the infrared detecting element on the cooling means.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. 1A and 1B are views showing the overall configuration of an embodiment of the present invention, FIG. 1A being a plan view and FIG. 1B being a side view. In the figure, reference numeral 11 is an infrared detecting element to which the present invention is applied. The infrared detecting element 11 is an infrared detecting element adopting an indirect hybrid system, and is configured as follows.

That is, as shown in a perspective view showing a part of the infrared detecting element of FIG. 2, an infrared receiving section 13 is provided in the vicinity of the center of the sapphire substrate 12, and the infrared receiving section 13 is provided. Si signal processing circuit 1 near both sides of the
4 are arranged respectively. A protective film made of silicon dioxide (SiO ₂ ) is formed on the surface of the sapphire substrate 12.

The infrared ray receiving portion 13 is composed of mercury, cadmium,
It is composed by forming a pair of electrodes on both sides of a crystal block such as tellurium, and by applying a bias current between these electrodes, a resistance value that changes according to the intensity of incident infrared rays is signaled as a voltage change. This is taken out to the processing Si circuit 14.

In FIG. 1, reference numeral 15 is a cold shield for limiting the viewing angle of the infrared rays incident on the infrared light receiving portion 13, and this cold shield 15 is also shown in the enlarged perspective view of FIG. In addition, an infrared transmitting window (opening) 16 is provided at a position corresponding to the infrared light receiving portion 13, and a plurality of box-like shield main bodies 17 (four in this example) are formed so as to cover the entire infrared light receiving portion 13. ) Legs 18 are integrally provided.

These legs 18 are the Si circuits 1 for signal processing.
The fixing portion 19 formed so as to straddle the four and abut on each of the corners of the sapphire substrate 12 at the tip thereof.
have. In the cold shield 15, the fixing portions 19 at the tips of the legs 18 are fixed by screws 20 near the corners of the sapphire substrate 12.

Further, the reason why the cold shield 15 is fixed to the sapphire substrate 12 by the screw 20 as described above is that the infrared detecting element 11 is inconvenient (obstacle).
If there is, remove the cold shield 15,
This is because appropriate treatment (repair, etc.) can be performed.
The cold shield 15 is not fixed to the sapphire substrate 12 by screws, but a permanent fixing method such as adhesion may be used.

As shown in FIG. 1, the infrared detecting element 11 constructed as described above is fixed and mounted on the cooling head 21 of the cooling means to connect the signal processing Si circuit 14 and the external circuit. An infrared detector is configured by performing other things.

According to the infrared detecting element 11 shown in this embodiment, the cold shield 15 fixes the shield body 17 covering the infrared receiving portion 13 to the sapphire substrate 12 by the fixing portion 19 at the tip of the leg 18. Therefore, the cold shield can be made smaller and lighter and the heat capacity can be reduced compared to the conventional one in which the cold shield is fixed to the cooling head separately from the infrared detector. The burden of cooling by the installed cooling means is reduced, and the price and size of the infrared detector can be reduced.

Further, since the cold shield 15 is integrally fixed to the sapphire substrate 12, it is only necessary to fix the infrared detecting element 11 to a cooling means or the like, and the adjustment as in the prior art is unnecessary.

FIG. 4 is a sectional view showing another embodiment of the present invention, showing the internal construction of the cold shield 15 (shield body 17) of the above-mentioned embodiment. The same components as those in the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted.

Shield body 17 of cold shield 15
A plurality of projecting fins 22a and 22b are integrally provided inside. These fins 22a and 22b are
This is to prevent infrared rays (stray light) reflected on the inner surface of the shield body 17 from being incident on the infrared light receiving section 13, which is not the normal infrared ray entering the infrared light receiving section 13, and further reflects the stray light to increase its power. It is for damping.

A bandpass filter 23 made of germanium (Ge) or the like is supported and fixed to the fins 22a and 22b. Such fins 22a,
By using 22b as a fixing member of the bandpass filter 23, the structure of the cold shield 15 is simplified.

As a method of manufacturing such a cold shield 15, as shown in the figure, the shield body 17 is divided into an upper member a and a lower member b, and the bandpass filter 23 is used as the upper member a. After the fin 22a and the fin 22b of the lower member b are sandwiched and arranged, the joint portion of the upper member a and the lower member b can be fixed by welding or the like.

Although not shown, the shield main body 17, the fins 22a and 22b, and the bandpass filter 23, which have the same structure as that shown in FIG. 4, are used as a bandpass filter forming material. A portion (shield body 17 and fins 22) formed integrally with germanium or the like other than a predetermined portion facing the infrared light receiving portion 13
A black shield with a bandpass filter can be obtained by blackening the entire surface of the portions corresponding to a and 22b). In this way, the cold shield can be manufactured (assembled) more easily than the configuration shown in FIG.

[0027]

Since the present invention is constructed as described above, the cold shield is small, lightweight and has a small heat capacity. Therefore, if an infrared detector is constructed using the infrared detecting element to which the present invention is applied, cooling is achieved. Therefore, it is possible to reduce the burden associated with the above, and to reduce the price and size of the infrared detector.

Further, since the cold shield is fixed to the sapphire substrate, there is also an effect that it becomes unnecessary to adjust the positional relationship between the cold shield and the infrared receiving part when the infrared detecting element is mounted on the cooling means. .

[Brief description of drawings]

FIG. 1 is a plan view (A) and a side view (B) showing an overall configuration of an embodiment of the present invention.

FIG. 2 is a perspective view showing a part of an infrared detection element according to an embodiment of the present invention.

FIG. 3 is a perspective view of a cold shield according to an embodiment of the present invention.

FIG. 4 is a sectional view showing a main part of a cold shield according to another embodiment of the present invention.

FIG. 5 is a diagram showing a conventional technique.

[Explanation of symbols]

 11 Infrared Detector 12 Sapphire Substrate 13 Infrared Receiver 14 Signal Processing Si Circuit 15 Cold Shield 16 Infrared Transmission Window 17 Shield Body 18 Leg 19 Fixing Part 20 Screw 21 Cooling Head 22a, 22b Fin 23 Bandpass Filter

Front page continuation (72) Inventor Tomofumi Ueda 1015 Kamiodanaka, Nakahara-ku, Kawasaki, Kanagawa, Fujitsu Limited Inventor Tokutomo Sato 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Fujitsu Limited

Claims (5)

[Claims] 1. An infrared detecting element comprising an infrared light receiving portion on a sapphire substrate and a circuit for signal processing adjacent to the infrared light receiving portion, wherein an infrared transmitting window is provided at a position corresponding to the infrared light receiving portion. ,
An infrared detecting element, characterized in that a cold shield for limiting the viewing angle of the infrared receiving section is installed in an empty space around the infrared receiving section to cover the entire infrared receiving section. 2. The infrared detection element according to claim 1, wherein the cold shield has a plurality of legs having a fixing portion that is in contact with a shield main body in the vicinity of a corner of the sapphire substrate across the signal processing circuit. An infrared detecting element, which is integrally provided and fixed to the sapphire substrate by the fixing portion. 3. The infrared detection element according to claim 2, wherein a protruding fin for preventing stray light is provided inside the shield body, and a bandpass filter that transmits only infrared rays in a predetermined frequency band is attached to the fin. Infrared detecting element characterized by the above. 4. The infrared detecting element according to claim 3, wherein the entire shield body, the fins, and the bandpass filter are integrally made of a material forming a bandpass filter that transmits only infrared rays in a predetermined frequency band. Form,
An infrared detecting element characterized by being entirely blackened except a portion corresponding to the bandpass filter. 5. The infrared detecting element according to claim 1, wherein the cold shield is detachably screwed and fixed to the sapphire substrate.