Non-contact Dewar cold finger supporting structure and infrared detector

Abstract

The utility model provides a non-contact type Dewar cold finger supporting structure which comprises an annular supporting plate fixedly connected between a cold finger and a Dewar shell, the outer side of the annular supporting plate is fixed to the Dewar shell, and a certain gap is formed between the inner side of the annular supporting plate and the cold finger. A plurality of open grooves are formed in the plate face of the annular supporting plate so that the annular supporting plate can have elasticity in the radial direction. According to the utility model, the annular support plate is additionally arranged between the Dewar shell and the cold finger, and the open slot is designed on the annular support plate, so that the annular support plate has the required elastic potential energy to absorb the impact energy conducted to the cold finger by the impact vibration, thereby greatly reducing the swing amplitude of the cold finger, reducing the risk that a platinum-iridium wire is snapped and broken, and improving the reliability of the device. Meanwhile, the stress of the cold shield, the optical filter, the chip, the ceramic substrate and the like is greatly reduced, and the risks of fragmentation and falling are greatly reduced; and the annular support plate is not in direct contact with the cold finger, so that the cold loss of the Dewar is not increased.

Description

Technical Field

[0001] The utility model belongs to the technical field of infrared detectors, and particularly relates to a non-contact Dewar cold finger support structure and an infrared detector. Background Art

[0002] Infrared detectors are the core components of infrared technology and also the forerunners of the development of infrared technology. Infrared detectors have very wide applications in civil and military fields such as missile guidance, space exploration, early warning satellites, and reconnaissance. In the Dewar of a refrigerated infrared detector, the cold finger cylinder is a cantilever beam structure. At the same time, since the substrate and cold screen of the infrared detector are assembled at the top of the cold finger cylinder, the cold finger cylinder becomes the weakest mechanical link in the entire infrared detector assembly.

[0003] Fred Nicol et al. in the United States used a direct-contact support ring to reinforce the cantilever beam structure at the top of the cold finger. However, the direct-contact support ring sacrifices a large amount of cold loss of the Dewar, increases the burden on the refrigerator, and the force on the cold screen filter at the cold head when impacted does not decrease significantly, and the risk of falling off is still very high. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a non-contact Dewar cold finger support structure, which can at least solve some defects existing in the prior art.

[0005] To achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A non-contact Dewar cold finger support structure includes an annular support plate fixed between the cold finger and the Dewar housing. The outer side of the annular support plate is fixed on the Dewar housing, and there is a certain gap between the inner side of the annular support plate and the cold finger. A plurality of slots are provided on the plate surface of the annular support plate to make it elastic in the radial direction.

[0007] Further, the slots are spiral arc-shaped slots. A plurality of the spiral arc-shaped slots are arranged at intervals along the radial direction of the annular support plate. The lengths of the spiral arc-shaped slots are equal, and the ends of the plurality of spiral arc-shaped slots are arranged at equal intervals along the circumferential direction of the annular support plate.

[0008] Further, the width of the spiral arc-shaped slot is 0.2 - 1 mm, and the distance between adjacent two spiral arc-shaped slots is 0.2 - 1 mm.

[0009] Further, feed slots are provided at both ends of each spiral arc-shaped slot, and the diameter of the feed slot is larger than the width of the spiral arc-shaped slot.

[0010] Further, the thickness of the annular support plate is less than 2 mm.

[0011] Further, the annular support plate is a leaf spring.

[0012] Further, the annular support plate is made of Freeflex stainless steel material.

[0013] In addition, the present utility model also provides an infrared detector, which includes a Dewar assembly and the above non-contact Dewar cold finger support structure. The Dewar assembly includes a Dewar housing and a cold shield, a ceramic substrate, a chip and a cold finger disposed inside the Dewar housing. The ceramic substrate is located at the upper end of the cold finger. The cold shield and the chip are mounted on the ceramic substrate, and the chip is located inside the cold shield. The annular support plate is located between the Dewar housing and the cold finger. The outer side of the annular support plate is fixedly installed on the inner side wall of the Dewar housing. The inner side of the annular support plate is sleeved outside the cold finger and has a certain gap with the cold finger.

[0014] Further, the annular support plate is located at a position near the ceramic substrate in the upper part of the cold finger.

[0015] Further, there are a plurality of the annular support plates, which are arranged in sequence along the axis of the cold finger, and the distance between the inner sides of the plurality of annular support plates and the cold finger gradually increases from top to bottom.

[0016] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0017] By adding an elastic annular support plate between the Dewar housing and the cold finger and designing a slot on the annular support plate, the present utility model enables the annular support plate to have the required elastic potential energy in its radial direction to absorb the impact energy conducted to the cold finger by the impact vibration, thereby greatly reducing the swing amplitude of the cold finger, reducing the risk of breakage and snapping of the platinum-iridium wire. At the same time, the forces on the cold shield, the filter, the chip, the ceramic substrate, etc. are also greatly reduced, and the risks of fragmentation and falling off are significantly reduced; moreover, the annular support plate is not in direct contact with the cold finger, and the cold loss of the Dewar will not be increased.

[0018] The following will further describe the present utility model in detail with reference to the accompanying drawings. Description of the Drawings

[0019] Figure 1 It is a schematic structural diagram of the Dewar assembly of the infrared detector in the embodiment of the present utility model;

[0020] Figure 2 It is a schematic structural diagram of the annular support plate in the embodiment of the present utility model;

[0021] Figure 3 It is a top view of the annular support plate in the embodiment of the present utility model.

[0022] Description of reference numerals: 1, cold finger; 2, Dewar housing; 3, annular support plate; 4, ceramic substrate; 5, chip; 6, cold shield; 7, spiral arc groove; 8, feed slot opening. Detailed implementation mode

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0024] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0025] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or a contact connection or an integral connection; for those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0026] The terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features; in the description of the present invention, unless otherwise stated, the meanings of "multiple" and "several" are two or more.

[0027] Such as Figure 1 , Figure 2 and Figure 3As shown in the figure, this embodiment provides a non-contact Dewar cold finger support structure, including an annular support plate 3 fixedly connected between the cold finger 1 and the Dewar outer shell 2. The outer side of the annular support plate 3 is fixed on the Dewar outer shell 2, and there is a certain gap between the inner side of the annular support plate 3 and the cold finger 1. A number of slots are provided on the surface of the annular support plate 3 to make it elastic in the radial direction. Among them, the annular support plate 3 not only has slots designed on its surface to make it elastic in the radial direction and capable of elastic deformation, but also has a certain stiffness to ensure that a certain gap is maintained between the inner side of the annular support plate 3 and the cold finger 1. When there is no other external force except gravity, the inner side of the annular support plate 3 does not directly contact the cold finger 1.

[0028] In this embodiment, by designing such a non-contact Dewar cold finger support structure, when the detector is working normally, since there is no direct contact between the inner side of the annular support plate 3 and the cold finger 1, heat exchange will not occur through the annular support plate 3, so the cold loss of the Dewar will not increase and the burden on the refrigerator will not increase. When the detector assembly is affected by a relatively large magnitude of shock and vibration, the cantilever beam structure of the cold finger 1 will swing. When the swing reaches a certain amplitude, it will be blocked by the annular support plate 3. Due to the slot structure designed on the annular support plate 3, the annular support plate 3 can deform in its radial direction, and the energy brought by the impact is converted into the elastic potential energy of the annular support plate 3 and absorbed. The annular support plate 3 with appropriate strength can absorb a large amount of impact energy, greatly reducing the swing of the cold finger. Therefore, the forces on the cold shield 6, filter, chip 5, ceramic substrate 4, etc. on the cold finger 1 are greatly reduced, and the risks of fragmentation and shedding are reduced. At the same time, the swing amplitude of the lead wire (usually made of platinum-iridium wire) between the ceramic substrate 4 and the ceramic lead ring is reduced, the force on the lead wire is reduced, and the risk of lead wire breakage is reduced.

[0029] In some embodiments, the annular support plate 3 is made of Freeflex stainless steel (grade Freeflex) developed by Alleima Heraeus. The annular support plate 3 made in this way not only has a certain stiffness, but also has a certain elasticity itself. Of course, the material of the annular support plate 3 is not limited to Freeflex stainless steel, and other materials that can meet the requirements of the annular support plate 3 having both a certain stiffness and elasticity can be used. It is preferably designed that the thickness of the annular support plate 3 is less than 2 mm.

[0030] Preferably, the annular support plate 3 can be designed as a leaf spring structure. In this way, the annular support plate 3 can not only generate a certain amount of elastic potential energy in the radial direction, but also generate a certain amount of elastic potential energy in the axial direction, so as to absorb the impact energy of the cold finger 1 tilting due to shock and vibration to the greatest extent.

[0031] In a preferred embodiment, the slotted openings on the annular support plate 3 are designed as spiral arc-shaped slots 7. A plurality of the spiral arc-shaped slots 7 are arranged at intervals along the radial direction of the annular support plate 3, and the lengths of all the spiral arc-shaped slots 7 are equal. Each of the spiral arc-shaped slots 7 extends spirally from the inner ring to the outer ring of the annular support plate 3, and the ends of the plurality of spiral arc-shaped slots 7 are arranged at equal intervals along the circumferential direction of the annular support plate 3. For example, as Figure 2 shown, in this embodiment, three spiral arc-shaped slots 7 are designed on the plate surface of the annular support plate 3, and the starting ends of the three spiral arc-shaped slots 7 are evenly distributed along the inner ring on the side close to the inner ring of the annular support plate 3. Through this structural design, the stability of the overall structure of the annular support plate 3 and the force uniformity of the annular support plate 3 can be ensured.

[0032] Since the groove width and groove spacing of the spiral arc-shaped slot 7 affect the elastic potential energy of the annular support plate 3, in this embodiment, through the simulation effect analysis of the elastic potential energy of the annular support plate 3, the groove width of the spiral arc-shaped slot 7 is preferably designed to be 0.2 - 1 mm, and the spacing between two adjacent spiral arc-shaped slots 7 is 0.2 - 1 mm, so as to absorb a large amount of impact energy to a greater extent and greatly reduce the swing of the cold finger.

[0033] Optimally, feed slots 8 are provided at both ends of each of the spiral arc-shaped slots 7, and at the same time, the diameter of the feed slot 8 is designed to be slightly larger than the width of the spiral arc-shaped slot 7, so as to accurately machine the spiral arc-shaped slots 7 on the annular support plate 3.

[0034] In addition, as Figure 1As shown in the figure, this embodiment also provides an infrared detector, which includes a Dewar assembly and the above non-contact Dewar cold finger support structure. The Dewar assembly includes a Dewar housing 2 and a cold shield 6, a ceramic substrate 4, a chip 5, and a cold finger 1 disposed inside the Dewar housing 2. The ceramic substrate 4 is located at the upper end of the cold finger 1. The cold shield 6 and the chip 5 are mounted on the ceramic substrate 4, and the chip 5 is located inside the cold shield 6. The annular support plate 3 is located between the Dewar housing 2 and the cold finger 1. The outer side of the annular support plate 3 is fixedly installed on the inner side wall of the Dewar housing 2. The inner side of the annular support plate 3 is sleeved on the outside of the cold finger 1 and has a certain gap with the cold finger 1. In this infrared detector provided by this embodiment, a non-contact Dewar cold finger support structure is introduced into the Dewar. When the infrared detector is working normally, since there is no direct contact between the inner side of the annular support plate 3 and the cold finger 1, heat exchange will not occur through the annular support plate 3, and the cold loss of the Dewar will not increase, thus not increasing the burden on the refrigerator. When the infrared detector is affected by a relatively large magnitude of impact vibration, the cantilever beam structure of the cold finger 1 will swing. When the swing reaches a certain amplitude, it will be blocked by the annular support plate 3, and at the same time, the annular support plate 3 will deform. The energy brought by the impact is converted into the elastic potential energy of the annular support plate 3 and absorbed. An annular support plate 3 with an appropriate strength can absorb a large amount of impact energy and greatly reduce the swing of the cold finger. Therefore, the forces on components such as the cold shield 6, the chip 5, and the ceramic substrate 4 on the cold finger 1 are greatly reduced, and the risks of fragmentation and detachment are reduced. At the same time, the swing amplitude of the lead wire (usually made of platinum-iridium wire) between the ceramic substrate 4 and the ceramic lead ring is reduced, the force on the lead wire is reduced, and the risk of lead wire breakage is reduced.

[0035] Since the upper part of the cold finger 1 has the largest swing amplitude when the infrared detector is affected by a relatively large magnitude of impact vibration, preferably, the annular support plate 3 is located at the upper part of the cold finger 1 close to the ceramic substrate 4, and the annular support plate 3 is used to block the part with the largest swing amplitude of the cold finger 1 to absorb a large amount of impact energy to the greatest extent and greatly reduce the swing of the cold finger.

[0036] Optionally, since the swing amplitudes of the cold finger 1 are inconsistent during the swing process of the cold finger 1, and the swing amplitudes decrease sequentially from top to bottom, a plurality of annular support plates 3 can be arranged along the axis of the cold finger 1 from top to bottom to support the cold finger 1, and the distances between the inner sides of the plurality of annular support plates 3 and the cold finger 1 are designed to gradually increase from top to bottom. Such a design can ensure that when the swing amplitude of the cold finger 1 is small, only the uppermost annular support plate 3 blocks the swing of the cold finger 1. When the swing amplitude of the cold finger 1 increases, the upper two annular support plates 3 block the swing of the cold finger 1, and so on. Thus, the corresponding number of annular support plates 3 can be automatically adjusted according to the magnitude of the impact vibration received by the cold finger 1 to support the cold finger 1 and reduce the swing of the cold finger 1.

[0037] The above examples are only illustrative of the present utility model and do not constitute a limitation on the scope of protection of the present utility model. Any design identical or similar to the present utility model falls within the scope of protection of the present invention.

Claims

1. A non-contact Dewar cold finger support structure, characterized in that: It includes an annular support plate fixedly connected between the cold finger and the Dewar housing. The outer side of the annular support plate is fixed on the Dewar housing, there is a certain gap between the inner side of the annular support plate and the cold finger, and several slots are provided on the plate surface of the annular support plate to make it elastically deformable in the radial direction.

2. The non-contact Dewar cold finger support structure according to claim 1, characterized in that: The slots are spiral arc-shaped slots. A plurality of the spiral arc-shaped slots are arranged at intervals along the radial direction of the annular support plate. The lengths of the spiral arc-shaped slots are equal, and the ends of the plurality of spiral arc-shaped slots are arranged at equal intervals along the circumferential direction of the annular support plate.

3. The non-contact Dewar cold finger support structure according to claim 2, wherein: The width of the spiral arc-shaped slot is 0.2 - 1 mm, and the distance between two adjacent spiral arc-shaped slots is 0.2 - 1 mm.

4. The non-contact Dewar cold finger support structure according to claim 2, wherein: Knife inlet slots are provided at both ends of each spiral arc-shaped slot, and the diameter of the knife inlet slot is larger than the width of the spiral arc-shaped slot.

5. The non-contact Dewar cold finger support structure according to claim 1, characterized in that: The thickness of the annular support plate is less than 2 mm.

6. The non-contact Dewar cold finger support structure according to claim 1, wherein: The annular support plate is a leaf spring.

7. The non-contact Dewar cold finger support structure according to claim 1, characterized in that: The annular support plate is made of Freeflex stainless steel material.

8. An infrared detector, characterized in that: It includes a Dewar assembly and the non-contact Dewar cold finger support structure according to any one of claims 1 - 7. The Dewar assembly includes a Dewar housing and a cold shield, a ceramic substrate, a chip and a cold finger arranged inside the Dewar housing. The ceramic substrate is located at the upper end of the cold finger. The cold shield and the chip are installed on the ceramic substrate, and the chip is located inside the cold shield. The annular support plate is located between the Dewar housing and the cold finger. The outer side of the annular support plate is fixedly installed on the inner side wall of the Dewar housing, and the inner side of the annular support plate is sleeved outside the cold finger and has a certain gap with the cold finger.

9. The infrared detector according to claim 8, wherein: The annular support plate is located at the upper part of the cold finger near the ceramic substrate.

10. The infrared detector according to claim 8, wherein: There are a plurality of the annular support plates, which are arranged in sequence along the axis of the cold finger, and the gaps between the inner sides of the plurality of annular support plates and the cold finger gradually increase from top to bottom.

Images