Dewar and refrigeration type infrared detector

Abstract

The Dewar comprises a Dewar outer shell and a cold head structure arranged in the Dewar outer shell, the cold head structure comprises a cold finger air cylinder, a cold table, a base plate and a balance cushion block, the cold table is connected to the cold finger air cylinder, a first connecting face of the balance cushion block is fixedly connected with the cold table, and a second connecting face of the balance cushion block is fixedly connected with the base plate. The base plate is fixedly connected to the second connecting face of the balance cushion block, an assembling groove is formed in the first connecting face in a sunken mode, and the cold table is fixedly embedded in the assembling groove. According to the utility model, the first connecting surface of the balance cushion block is provided with the assembling groove, and the assembling groove is nested and matched with the cold table, so that the connection stability and reliability between the balance cushion block and the cold table can be improved, the risk that the balance cushion block falls off from the cold table is greatly reduced, and the impact vibration resistance of the Dewar and the infrared detector is remarkably improved; therefore, the infrared detector can meet the working requirements in a harsh environment.

Description

Technical Field

[0001] The utility model belongs to the technical field of infrared detectors, and particularly relates to a Dewar and a refrigerated infrared detector configured with the Dewar. Background Art

[0002] The refrigerated infrared detector is the core component of infrared technology and also the forerunner of the development of infrared technology; due to its high sensitivity, good environmental adaptability, strong anti-interference ability and other advantages, the infrared detector has very wide applications in civil and military aspects such as missile guidance, space exploration, early warning satellites and reconnaissance.

[0003] The cold head is the carrier that provides the working temperature for the focal plane device, mainly including a cold stage, a ceramic substrate, a readout circuit, a focal plane chip, etc. When the detector is working at a deep low temperature (about 80K), due to the difference in the thermal expansion coefficients of materials, thermal stress is generated in the chip, which may cause cracks inside the chip and result in the failure of the detector.

[0004] To alleviate the problem of thermal stress concentration in the detector chip at low temperature, generally a spacer is currently arranged between the cold stage and the ceramic substrate as a balancing layer. In the Dewar structure of the refrigerated infrared detector, the cold finger cylinder is a cantilever beam structure, and the spacer is arranged between the cold stage and the ceramic substrate, and both are bonded by low-temperature glue. Since the bonding area between the spacer and the cold stage is small and the bonding strength is limited; moreover, it is impossible to ensure complete alignment during the bonding process between the spacer and the cold stage, there is a risk of offset, and the reliability of the cold head part cannot be guaranteed. In application fields such as national defense security and environmental monitoring, the infrared detector may have to cope with harsh environments such as large-scale vibration and impact, and in such working conditions, there is a risk of detachment between the spacer and the cold stage. Summary of the Utility Model

[0005] The utility model relates to a Dewar and a refrigerated infrared detector configured with the Dewar, and can at least solve some defects of the prior art.

[0006] The utility model relates to a Dewar, including a Dewar housing and a cold head structure arranged in the Dewar housing, the cold head structure includes a cold finger cylinder, a cold stage, a substrate and a balancing spacer, the cold stage is connected to the cold finger cylinder, a first connection surface of the balancing spacer is fixedly connected to the cold stage, the substrate is fixedly connected to a second connection surface of the balancing spacer, an assembly groove is recessed on the first connection surface, and the cold stage is fixedly installed in the assembly groove.

[0007] As one of the implementation manners, the diameter of the second connection surface is larger than the diameter of the first connection surface.

[0008] As one of the implementation manners, the side of the balancing spacer close to the cold finger cylinder is frustum-shaped.

[0009] As one of the implementation manners, the bottom and / or the wall of the assembly groove are adhered to the cold stage.

[0010] As one of the implementation manners, when the bottom of the assembly groove is adhered to the cold stage, a first thickness-determining spacer structure is provided between the bottom of the assembly groove and the cold stage, and the gap between the bottom of the assembly groove and the cold stage is filled with glue.

[0011] As one of the implementation manners, the substrate is adhered to the second connection surface.

[0012] As one of the implementation manners, a second thickness-determining spacer structure is provided between the substrate and the second connection surface, and the gap between the substrate and the second connection surface is filled with glue.

[0013] As one of the implementation manners, the Dewar further includes a cold finger support structure, and the cold finger support structure is respectively connected to the Dewar housing and the cold head structure.

[0014] As one of the implementation manners, the cold finger support structure includes a plurality of support rods arranged around the cold finger cylinder. One end of each support rod is fixedly connected to the Dewar housing, and the other end is fixedly connected to the cold stage. A plurality of avoidance channels for the support rods to pass through are correspondingly provided on the balance pad.

[0015] The present utility model also relates to a refrigerated infrared detector configured with the above-mentioned Dewar.

[0016] The present utility model has at least the following beneficial effects:

[0017] In the present utility model, an assembly groove is provided on the first connection surface of the balance pad and is nested and matched with the cold stage, which can improve the connection stability and reliability between the balance pad and the cold stage, greatly reduce the risk of detachment between the balance pad and the cold stage, and significantly improve the shock and vibration resistance performance of the Dewar and the infrared detector, so that the infrared detector can meet the working requirements under harsh environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0019] Figure 1 And Figure 2 is a schematic structural diagram of the Dewar provided by the embodiment of the present utility model, wherein, Figure 2 Compared withFigure 1 A cold finger support structure is added;

[0020] Figure 3 and Figure 4 FIG. is a schematic structural view of the balance pad provided by an embodiment of the present invention, wherein, Figure 3 a balance pad provided with an avoidance channel is shown, Figure 4 a balance pad provided with a first thickness-fixed interval structure is shown. Detailed implementation manners

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Apparently, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0022] As Figures 1-4 , an embodiment of the present invention provides a Dewar, which includes a Dewar housing 7 and a cold head structure disposed in the Dewar housing 7. The cold head structure includes a cold finger cylinder 1, a cold stage 2, a substrate 4, and a balance pad 3. The cold stage 2 is connected to the cold finger cylinder 1. The first connection surface of the balance pad 3 is fixedly connected to the cold stage 2. The substrate 4 is fixedly connected to the second connection surface of the balance pad 3. An assembly groove 31 is recessed on the first connection surface, and the cold stage 2 is fixedly installed in the assembly groove 31.

[0023] Wherein, the cold stage 2 is coaxial with the cold finger cylinder 1.

[0024] The above-mentioned substrate 4 is preferably a ceramic substrate 4, and a detector chip 5 is generally installed on the substrate 4; and a cold shield 6 can be installed on the substrate 4.

[0025] The above-mentioned balance pad 3 is preferably a regular-shaped part, such as a cylindrical structural part, a frustum-shaped structural part, a prismatic structural part, a frustum-shaped structural part, etc. The balance pad 3 is preferably coaxial with the cold stage 2, so as to improve the coaxiality between the substrate 4 and the cold stage 2; in this structure, the axis of the assembly groove 31 coincides with the axis of the balance pad 3. In an alternative embodiment, a substrate positioning portion is provided on the second connection surface, and the substrate positioning portion ensures the installation accuracy of the substrate 4 on the second connection surface. Through the matching design between the substrate positioning portion and the assembly groove 31, even if the balance pad 3 is an irregular-shaped part, the coaxiality between the substrate 4 and the cold stage 2 can be ensured.

[0026] In this embodiment, an assembly groove 31 is provided on the first connecting surface of the balance pad 3 and nested with the cold stage 2, which can improve the connection stability and reliability between the balance pad 3 and the cold stage 2, greatly reduce the risk of detachment between the balance pad 3 and the cold stage 2, and significantly improve the shock and vibration resistance performance of the Dewar and the infrared detector, so that the infrared detector can meet the working requirements under harsh environments.

[0027] Among them, preferably, the first connecting surface is flush with the exposed tabletop of the cold stage 2 (this exposed tabletop is also the tabletop of the cold stage 2 close to the cold finger cylinder 1), for example, the groove depth of the assembly groove 31 is the same as or approximately the same as the thickness of the cold stage 2; preferably, the assembly groove 31 and the cold stage 2 are in clearance fit or transition fit, for example, the diameter of the assembly groove 31 is the same as or approximately the same as the diameter of the cold stage 2, to ensure that the cold stage 2 is embedded in the assembly groove 31.

[0028] Preferably, the bottom and / or the wall of the assembly groove 31 is / are bonded to the cold stage 2. Preferably, the assembly groove 31 and the cold stage 2 are bonded with a low-temperature adhesive. Preferably, both the bottom and the wall of the assembly groove 31 are bonded to the cold stage 2, which can further improve the connection reliability between the balance pad 3 and the cold stage 2.

[0029] In one embodiment, as Figure 4 , when the bottom of the assembly groove 31 is bonded to the cold stage 2, a first thickness-setting spacer structure 33 is provided between the bottom of the assembly groove 31 and the cold stage 2, and the glue fills the gap between the bottom of the assembly groove 31 and the cold stage 2. By providing the first thickness-setting spacer structure 33, the thickness of the glue at the bonding interface between the bottom and the cold stage 2 can be ensured to be uniform, so as to ensure the firmness after bonding.

[0030] Among them, the above-mentioned first thickness-setting spacer structure 33 can adopt a plurality of thickness-setting strips, and the thickness-setting strips are preferably distributed in parallel.

[0031] Among them, the above-mentioned first thickness-setting spacer structure 33 can be formed on the bottom of the assembly groove 31 and / or formed on the cold stage 2. Preferably, the first thickness-setting spacer structure 33 is formed on the bottom of the assembly groove 31, for example, a plurality of thickness-setting strips are provided on the bottom of the assembly groove 31.

[0032] Optionally, the distance between the bottom of the assembly groove 31 and the cold stage 2 is in the range of 10 - 100 um, that is, the thickness defined by the above-mentioned first thickness-setting spacer structure 33 is in the range of 10 - 100 um, and further preferably controlled in the range of 10 - 30 um, to ensure sufficient glue thickness and at the same time ensure the bonding strength between the balance pad 3 and the cold stage 2.

[0033] Preferably, the substrate 4 is bonded to the second joint surface. Preferably, a low-temperature adhesive is used to bond the substrate 4 and the balance pad 3.

[0034] In one embodiment, a second thickness-setting spacer structure is provided between the substrate 4 and the second joint surface, and the gap between the substrate 4 and the second joint surface is filled with glue. By providing the second thickness-setting spacer structure, the thickness of the glue at the bonding interface between the substrate 4 and the balance pad 3 can be ensured to be uniform, thus ensuring the firmness after bonding.

[0035] Among them, the above-mentioned second thickness-setting spacer structure can adopt a plurality of thickness-setting bars, and the thickness-setting bars are preferably distributed in parallel.

[0036] Among them, the above-mentioned second thickness-setting spacer structure can be formed on the substrate 4 and / or on the second joint surface. Preferably, the second thickness-setting spacer structure is formed on the second joint surface. For example, a plurality of thickness-setting bars are provided on the second joint surface.

[0037] Optionally, the distance between the substrate 4 and the second joint surface is in the range of 10 - 100 μm, that is, the thickness defined by the above-mentioned second thickness-setting spacer structure is in the range of 10 - 100 μm, and further preferably controlled in the range of 10 - 30 μm, ensuring sufficient glue thickness and at the same time ensuring the bonding strength between the balance pad 3 and the substrate 4.

[0038] In one embodiment, as Figures 1-4 , the diameter of the second joint surface is larger than the diameter of the first joint surface, which can correspondingly increase the connection area between the balance pad 3 and the substrate 4, improve the installation stability of the substrate 4 and the chip 5, and at the same time facilitate the dispersion and dissipation of the thermal stress of the chip 5. Optionally, as Figure 3 and Figure 4 , the side of the balance pad 3 close to the cold finger cylinder 1 is frustum-shaped; further, the balance pad 3 can include a connected frustum section and a cylindrical section. The frustum section is located on the side close to the cold finger cylinder 1, and the cylindrical section is located on the side close to the substrate 4. This structure can correspondingly improve the structural strength of the balance pad 3 and the reliability of the connection with the cold stage 2 and the substrate 4.

[0039] In one embodiment, the dewar further includes a cold finger support structure, and the cold finger support structure is respectively connected to the dewar housing 7 and the cold head structure. The support structure has a support and fixation effect on the cold head structure, which can preferably solve problems such as large swing amplitude and easy breakage / pulling breakage caused by the cantilever structure of the cold finger cylinder 1, and reduce the risk of breakage / pulling breakage of the platinum-iridium wire in the cold finger cylinder 1.

[0040] Optionally, as Figure 2The cold finger support structure includes a plurality of support rods 8 arranged around the cold finger cylinder 1, one end of the support rod 8 is fixedly connected to the dewar housing 7, and the other end is fixedly connected to the cold stage 2. On this basis, Figure 3 It is preferred that a plurality of avoidance channels 32 for the support rods 8 to pass through are matchedly arranged on the balancing pad 3 to facilitate the connection between the support rods 8 and the cold table 2; including but not limited to grooving / opening holes on the balancing pad 3 to form the above-mentioned avoidance channels 32.

[0041] In addition, the embodiment of the utility model also provides a cooling type infrared detector, which is equipped with the above-mentioned Dewar.

[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A dewar, comprising a dewar shell and a cold head structure arranged in the dewar shell, wherein the cold head structure comprises a cold finger cylinder, a cold stage, a substrate and a balancing pad, wherein the cold stage is connected to the cold finger cylinder, the first connecting surface of the balancing pad is fixedly connected to the cold stage, and the substrate is fixedly connected to the second connecting surface of the balancing pad, characterized in that: The first connecting surface is recessed to form an assembly groove, and the cold stage is embedded and fixed in the assembly groove.

2. The Dewar according to claim 1, characterized in that: A diameter of the second connecting surface is greater than a diameter of the first connecting surface.

3. The Dewar according to claim 2, characterized in that: The side of the balancing pad close to the cold finger cylinder is in a frustum shape.

4. The Dewar according to claim 1, characterized in that: The groove bottom and / or groove wall of the assembly groove are bonded to the cold stage.

5. The Dewar according to claim 4, characterized in that: When the groove bottom of the assembly groove is bonded to the cold stage, a first constant thickness spacing structure is provided between the groove bottom of the assembly groove and the cold stage, and glue fills the gap between the groove bottom of the assembly groove and the cold stage.

6. The Dewar according to claim 1, characterized in that: The substrate is bonded to the second connecting surface.

7. The Dewar according to claim 1, characterized in that: A second constant thickness spacing structure is provided between the substrate and the second connection surface, and glue fills the gap between the substrate and the second connection surface.

8. The Dewar of claim 1, wherein: It also includes a cold finger support structure, which is connected to the Dewar shell and the cold head structure respectively.

9. The Dewar of claim 8, wherein: The cold finger support structure includes a plurality of support rods arranged around the cold finger cylinder, one end of the support rod is fixedly connected to the dewar shell, and the other end is fixedly connected to the cold stage, and a plurality of avoidance channels for the support rods to pass through are matched on the balance pad.

10. A refrigerated infrared detector, characterized in that: The invention is provided with the Dewar according to any one of claims 1 to 9.

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