Dewar assembly and infrared detector

Abstract

The application provides a Dewar assembly and an infrared detector, the Dewar assembly comprising a Dewar shell, a tubular getter unit, an annular fixing unit and a lead ring unit; the lead ring unit comprising a lead ring body and a lead ring shell, the lead ring body being arranged on the lead ring shell, and the lead ring shell being fixedly connected with the Dewar shell; the annular fixing unit comprising an annular body and a first protruding part arranged on the annular body, the first protruding part being inserted into the tubular getter unit to form an interference fit and fix the annular body on the lead ring shell. In the application, the annular fixing unit is used to form an interference fit with the tubular getter unit to fix the annular body on the lead ring shell. Compared with the related art, the application not only has a simple and practical structure and is convenient to assemble, but also correspondingly reduces the risk of air leakage and air release of the Dewar shell by reducing the number of openings, weldings and scratches on the inner wall of the Dewar shell, thereby improving the vacuum reliability of the Dewar assembly.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor, in particular to a Dewar assembly and an infrared detector. BACKGROUND

[0002] The infrared detector mainly comprises a chip, a Dewar assembly and a refrigerator. The Dewar assembly of the infrared detector provides a vacuum working environment for the chip. The vacuum lifetime is an important reliability index of the Dewar assembly of the infrared detector. In order to ensure the vacuum reliability of the infrared detector, an activatable getter unit can be installed in the Dewar assembly. When the infrared detector is used for a period of time, the getter unit in the Dewar assembly can be activated to adsorb the gas released by the internal materials of the Dewar assembly, so as to ensure the vacuum lifetime of the infrared detector and improve the reliability of the infrared detector.

[0003] In the infrared detector of the related art, an ohmic ring (Ω ring), an L-shaped sheet and an insulator are usually used to fix and electrically connect the getter unit. The specific process can be, for example: a hole is opened on the Dewar shell of the Dewar assembly, and an insulator is welded to make the insulator extend into the inside of the Dewar shell for connecting one end of the getter unit, then an ohmic ring is used to hold the getter unit, and the ohmic ring is welded to the inner wall of the Dewar shell, then an L-shaped sheet is welded to the inner wall of the Dewar shell, one end of the electrode of the getter unit is connected to the L-shaped sheet, and one end is connected to the insulator to form a conduction loop.

[0004] In the above related art, the hole needs to be opened on the Dewar shell and the getter unit needs to be welded multiple times in order to fix and electrically connect the getter unit, which not only increases the welding seam of the Dewar shell and increases the risk of gas leakage, but also damages the surface passivation layer of the inner wall of the Dewar shell due to multiple weldings, which increases the risk of material gas production, and is not conducive to the maintenance of the vacuum degree inside the Dewar. At the same time, the insulator protrudes from the outer surface of the Dewar shell and is easily subjected to external force impact. Since the insulator itself is not strong enough, it is easy to deform or leak after being subjected to external force, which increases the risk of Dewar vacuum failure. SUMMARY

[0005] The present application aims to provide a Dewar assembly and an infrared detector to improve the vacuum reliability of the Dewar assembly.

[0006] Another object of the present application is to facilitate the assembly of the Dewar assembly.

[0007] To solve the above technical problems, the present application provides a dewar assembly, which comprises a dewar shell, a tubular getter unit, an annular fixing unit and a lead ring unit; the lead ring unit comprises a lead ring body and a lead ring shell, the lead ring body is arranged on the lead ring shell, and the lead ring shell is fixedly connected with the dewar shell; the annular fixing unit comprises an annular body and a first protruding part arranged on the annular body, the first protruding part is arranged in the tubular getter unit to form an interference fit and fix the annular body on the lead ring shell.

[0008] Optionally, the tubular getter unit comprises a tubular getter body and two electrode ends, and the two electrode ends are located on the same side of the tubular getter body.

[0009] Optionally, the lead ring body has a lead pin, and the lead pin is welded with the electrode end for electrical lead-out.

[0010] Optionally, the annular fixing unit further comprises a second protruding part, the second protruding part is arranged on the annular body, and the first protruding part is arranged on the second protruding part.

[0011] Optionally, the first protruding part and the second protruding part are at least partially hollow structures.

[0012] Optionally, the hollow structure is a cavity penetrating through the first protruding part, the second protruding part and the annular body.

[0013] Optionally, the cross-sectional area of the second protruding part is smaller than the cross-sectional area of the tubular getter unit.

[0014] Optionally, the material of the annular fixing unit is metal.

[0015] Optionally, the lead ring shell is provided with a step relative to the inner wall of one end of the lead ring body, and the annular fixing unit is fixed to the inner wall of the lead ring shell by the step.

[0016] Based on another aspect of the present application, the embodiment further provides an infrared detector, which comprises the dewar assembly as described above.

[0017] In summary, the Dewar assembly and infrared detector provided by the present application have the following beneficial effects: the first protruding part of the annular fixing unit extends into the tubular getter unit to form an interference fit to fix the tubular getter unit to the lead ring shell, and the lead ring shell is connected to the Dewar shell to form the Dewar assembly. Compared with the opening and welding of the insulator, ohmic ring and L-shaped bracket in the related art, the structure is simple and practical, the assembly is convenient, and the opening, multiple welding and scratching of the inner wall of the Dewar shell are reduced, thereby reducing the risk of leakage and outgassing (gas generation) of the Dewar shell, and improving the vacuum reliability of the Dewar assembly. BRIEF DESCRIPTION OF DRAWINGS

[0018] Those skilled in the art will understand that the provided drawings are for the purpose of better illustrating the present application and do not constitute any limitation on the scope of the present application.

[0019] Figure 1 is a cross-sectional view of the Dewar assembly provided by the present application;

[0020] Figure 2 is a first partial cross-sectional view of the Dewar assembly provided by the present application;

[0021] Figure 3 is a second partial cross-sectional view of the Dewar assembly provided by the present application.

[0022] In the drawings:

[0023] 10 - Dewar shell; 11 - first Dewar shell; 12 - second Dewar shell;

[0024] 20 - tubular getter unit; 21 - tubular getter body; 22 - electrode end;

[0025] 30 - annular fixing unit; 31 - first protruding part; 32 - second protruding part; 33 - annular body; 331 - first surface; 332 - second surface;

[0026] 40 - lead ring unit; 41 - lead ring body; 411 - lead pin; 42 - lead ring shell; 421 - step;

[0027] 51 - base; 52 - chip; 53 - cold finger. DETAILED DESCRIPTION

[0028] In order to make the objects, advantages and features of the present application more clearly, the following further describes the present application in detail with reference to the accompanying drawings and specific embodiments. It should be noted that the drawings are very simplified and not drawn in proportion, and are only used to facilitate and clarify the purpose of assisting the description of the embodiments of the present application. In addition, the structures shown in the drawings are often a part of the actual structures. In particular, the emphasis shown in each drawing is different, and sometimes different proportions are used.

[0029] It should be understood that when an element or layer is referred to as being "on", "connected to" or "coupled to" another element or layer, it can be directly on, connected or coupled to the other element or layer, or intervening elements or layers can be present. In contrast, when an element is referred to as being "directly on", "directly connected to" or "directly coupled to" another element or layer, then there are no intervening elements or layers present. Although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or sections, these terms are not intended to limit these elements, components, regions, layers and / or sections. These terms are simply used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present application. Spatially relative terms such as "beneath", "below", "lower", "above", "upper", and the like can be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" or "over" the other elements or features. The device can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. The terms of degree such as "substantially", "approximately", and the like, are used herein to account for manufacturing tolerances, imperfections, variations and / or differences at the component level that can be described herein and variations at the device level that can arise as a result. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising", when used in this specification, specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0030] The present application provides a Dewar assembly and an infrared detector, which can improve the vacuum reliability of the Dewar assembly and facilitate the assembly of the Dewar assembly.

[0031] wherein, Figure 1 is a schematic diagram of the Dewar assembly provided by the embodiments of the present application.

[0032] As Figure 1 shown, the Dewar assembly provided by the embodiments of the present application comprises a Dewar shell 10, a tubular getter unit 20, a ring-shaped fixing unit 30 and a lead ring unit 40. The lead ring unit 40 comprises a lead ring body 41 and a lead ring shell 42, the lead ring body 41 is arranged on the lead ring shell 42, and the lead ring shell 42 is fixedly connected with the Dewar shell 10. The ring-shaped fixing unit 30 comprises a ring-shaped body 33 and a first protruding part 31 arranged on the ring-shaped body 33, the first protruding part 31 is used to extend into the tubular getter unit 20 to form an interference fit and fix the ring-shaped body 33 on the lead ring shell 42.

[0033] In the embodiments, the number of the tubular getter units 20 can be one or more, and the plurality of tubular getter units 20 are arranged on the ring-shaped fixing unit 30 uniformly. In the embodiments, as Figure 2 shown, two tubular getter units 20 are arranged symmetrically on the ring-shaped fixing unit 30. As Figure 3 shown, the tubular getter unit 20 comprises a tubular getter body 21 and two electrode ends 22, and the two electrode ends 22 are located on the same side of the tubular getter body 21. Specifically, the two electrode ends 22 are arranged on the side of the getter body close to the chip 52, so as to be electrically connected with the lead ring unit 40, and are used to activate the tubular getter body 21. Compared with the columnar (solid) getter unit, the tubular getter body 21 has a larger surface area, has a better gettering effect, and is more convenient to realize the fixing effect in the embodiments.

[0034] Please continue to refer to Figure 1 , the tubular getter body 21 is provided with a ring-shaped fixing unit 30 on the side opposite to the electrode end 22 (the lead ring body 41), and the ring-shaped fixing unit 30 is used to fix the tubular getter body 21. Specifically, the ring-shaped fixing unit 30 comprises a ring-shaped body 33, a first protruding part 31 and a second protruding part 32. The ring-shaped body 33 can be, for example, a circular ring, the outer diameter of the circular ring is slightly smaller than the inner diameter of the lead ring shell 42, the ring-shaped body 33 comprises a first surface 331 and a second surface 332 arranged oppositely, the second protruding part 32 is arranged on the first surface 331 of the ring-shaped body 33, and the first protruding part 31 is arranged on the second protruding part 32. The first protruding part 31 is used to extend into the interior of the tubular getter body 21 and form an interference fit to fix the tubular getter body 21 on the ring-shaped fixing unit 30.

[0035] In a preferred embodiment, the first protrusion 31 is a cylinder matching the inner part of the tubular getter body 21. The interference fit between the first protrusion 31 and the tubular getter body 21 provides a better fixing effect with a reduced contact area, and thus relatively improves the gettering effect of the tubular getter body 21. It should be understood that, compared to fixing the getter unit from the outside in the prior art, fixing the tubular getter body 21 from the inside in the present embodiment can reduce the contact area between the first protrusion 31 and the tubular getter body 21, i.e. relatively increase the exposed area of the tubular getter body 21, thereby improving the gettering effect.

[0036] The cross-sectional area of the second protrusion 32 (e.g. circular) is larger than that of the first protrusion 31 for positioning the tubular getter body 21 during assembly, and is smaller than that of the tubular getter body 21 for reducing the contact area between them, thereby reducing the influence on the gettering effect.

[0037] Further, the first protrusion 31 and the second protrusion 32 are at least partially hollow to reduce the weight of the annular fixing unit 30 for improving the fixing effect, and to reduce material consumption. Preferably, the hollow structure is a cavity extending through the first protrusion 31, the second protrusion 32 and the annular body 33. The material of the annular fixing unit 30 can be any suitable metal material, e.g. the same as the material of the dewar shell (4J29).

[0038] Please continue to refer to Figure 1The lead ring unit 40 comprises a lead ring body 41 and a lead ring shell 42. Specifically, the lead ring body 41 comprises a plurality of lead pins 411 for connecting the inside and outside of the Dewar assembly, and the lead ring body 41 is arranged on the side of the lead ring shell 42 close to the chip 52, so as to electrically connect the chip 52 and the tubular getter unit 20, thereby realizing information transmission of the chip 52 and activation of the tubular getter unit 20. The lead ring shell 42 is used to fix the lead ring body 41 and the annular fixing unit 30. Preferably, the lead ring shell 42 is provided with at least one step 421 protruding from the inner wall of the lead ring shell 42 at one end of the lead ring body 41, and the step 421 is used to facilitate assembly of the Dewar assembly. The step 421 has a step surface perpendicular to the inner wall of the lead ring shell 42, and the step surface faces away from the lead ring body 41. During assembly, the first surface 331 of the annular fixing unit 30 is in contact with the step surface, and the edge (or sidewall) of the second surface 332 of the annular fixing unit 30 is welded to the inner wall of the lead ring shell 42. It should be understood that the step 421 can be a continuous whole around the inner wall of the lead ring shell 42, or a plurality of separate small steps 421 arranged uniformly. Of course, if the lead ring shell 42 is not provided with the step 421, other auxiliary tools can also be used to realize assembly, and the fixing mode of the annular fixing unit 30 and the lead ring shell 42 can also be, for example, adhesion.

[0039] It should be noted that in the present embodiment, the height of the lead ring shell 42 needs to completely cover the height of the lead ring body 41, the tubular getter unit 20 and part of the annular fixing unit 30 (the annular body 33 and the second protruding part 32), so as to facilitate assembly of the three.

[0040] Please continue to refer to Figure 1The Dewar assembly 10 includes a first Dewar shell 11 and a second Dewar shell 12, which are welded to the two ends of the lead ring shell 42 and are connected with the base 51 and the cold fingers 53 arranged on the base 51 to form a closed cavity for providing a vacuum environment for the chip 52. In the embodiment, the first Dewar shell 11 can be located at the end of the Dewar assembly close to the chip 52, and the first Dewar shell 11 (also referred to as a window frame component) is provided with an optical window as an entrance for light of a specific waveband; the second Dewar shell 12 can be located at the end of the Dewar assembly away from the chip 52, and the second Dewar shell 12 is fixedly connected with the base 51 away from the side of the lead ring shell 42 away from the chip 52, and a refrigerator connected with the base 51 is used to provide a low-temperature environment for the Dewar assembly 10 and the chip 52. The first Dewar shell 11, the second Dewar shell 12 and the lead ring shell 42 can be made of the same metal material, for example, 4J29. Moreover, the inner walls of the first Dewar shell 11, the second Dewar shell 12, the lead ring shell 42 and the base 51 and the outer wall of the cold fingers 53 are provided with a passivation layer, for example, a nickel plating layer, to prevent the shell material from generating gas, which is not conducive to the stability of the vacuum in the Dewar assembly 10.

[0041] Specifically, the assembly process of the Dewar assembly in the embodiment can be, for example: first, the tubular getter unit 20 is assembled to the first protruding part 31 of the annular fixing unit 30 by interference fit, then the first surface 331 of the annular fixing unit 30 is placed on the step 421 of the lead ring shell 42, the annular fixing unit 30 is welded to the inner wall of the lead ring shell 42 from the second surface 332 of the annular fixing unit 30, the electrode end 22 of the tubular getter unit 20 is welded to the lead pin 411 of the lead ring body 41, thereby realizing the fixation and electrical connection of the tubular getter unit 20 on the lead ring shell 42, and then the first Dewar shell 11 and the second Dewar shell 12 are welded to the two ends of the lead ring shell 42 for the assembly of the Dewar assembly. In the assembly process of the Dewar assembly in the embodiment, the tubular getter unit 20 is directly fixed to the lead ring shell 42 by the annular fixing unit 30, which reduces the assembly of the insulator, the ohmic ring and the L-shaped bracket in the related art, is more convenient and easy to operate, and reduces the risk of leakage and outgassing (generation of gas) of the Dewar shell by reducing the operations and processes such as the opening of holes on the inner wall of the Dewar shell, multiple weldings and scratching of the inner wall of the Dewar shell.

[0042] The embodiment of the present application also provides an infrared detector, which comprises a dewar assembly, a chip and a refrigerator, the dewar assembly is the dewar assembly as described above, and comprises a dewar shell, a tubular getter unit, an annular fixing unit, a lead ring unit, a base and a cold finger, so as to form a closed cavity for providing a vacuum environment, the refrigerator is located at the bottom of the base and is connected with the cold finger cylinder for providing a cold source for the dewar assembly, and the chip is arranged in the closed cavity and at one end of the cold finger, so as to receive the cold source provided by the refrigerator.

[0043] In conclusion, the dewar assembly and the infrared detector provided by the present application have the following beneficial effects: the first protruding part of the annular fixing unit is inserted into the tubular getter unit to form an interference fit, so as to fix the tubular getter unit to the lead ring shell, and the lead ring shell is connected with the dewar shell to form the dewar assembly, compared with the opening and welding of the insulator, the ohmic ring and the L-shaped support in the related art, not only the structure is simple and practical, and the assembly is convenient, but also the opening on the dewar shell, the multiple welding and the scratch on the inner wall of the dewar shell are reduced, so as to reduce the risk of leakage and outgassing (gas generation) of the dewar shell, and the vacuum reliability of the dewar assembly is improved.

[0044] The above description is only a description of the preferred embodiment of the present application, and does not limit the scope of the present application in any way, and any modification and change made by the person skilled in the art according to the above disclosure is within the protection scope of the claims.

Claims

1. A dewar assembly characterized by, The dewar assembly comprises a dewar shell, a tubular getter unit, a ring-shaped fixing unit and a lead ring unit. The lead ring unit comprises a lead ring body and a lead ring shell, the lead ring body is arranged on the lead ring shell for leading out the tubular getter unit, and the lead ring shell is fixedly connected with the dewar shell for fixing the lead ring body and the ring-shaped fixing unit. The ring-shaped fixing unit is used for fixing the tubular getter unit and comprises a ring-shaped body and a first protruding part arranged on the ring-shaped body, the first protruding part is used for protruding into the tubular getter unit to form an interference fit and fix the ring-shaped body on the lead ring shell.

2. The dewar assembly of claim 1, wherein, The tubular getter unit comprises a tubular getter body and two electrode ends, and the two electrode ends are located on the same side of the tubular getter body.

3. The dewar assembly of claim 2, wherein, The lead ring body has a lead pin, and the lead pin is welded with the electrode end for electrical lead-out.

4. The dewar assembly of claim 1, wherein, The ring-shaped fixing unit further comprises a second protruding part, the second protruding part is arranged on the ring-shaped body, and the first protruding part is arranged on the second protruding part.

5. The dewar assembly of claim 4, wherein, The first protruding part and the second protruding part are at least partially hollow structures.

6. The dewar assembly of claim 5, wherein, The hollow structure is a cavity penetrating through the first protruding part, the second protruding part and the ring-shaped body.

7. The dewar assembly of claim 4, wherein, The cross-sectional area of the second protruding part is smaller than that of the tubular getter unit.

8. The dewar assembly of claim 1, wherein, The material of the ring-shaped fixing unit is metal.

9. The dewar assembly of claim 1, wherein, The lead ring shell is provided with a step relative to the inner wall of one end of the lead ring body, and the ring-shaped fixing unit is fixed to the inner wall of the lead ring shell by the step.

10. An infrared detector, characterized by The infrared detector comprises the dewar assembly according to any one of claims 1 to 9.

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