A cold screen and refrigerated infrared detector with a wavy integrated structure

Abstract

The present invention belongs to the field of infrared detection sensors and proposes a cold screen for a refrigerated infrared detector. Specifically, it is a cold screen with a wavy, integrated structure. The cold screen has a wavy appearance and is directly processed using a single electroforming process. The inner surface of the cold screen is blackened, and the outer surface can be gold-plated or untreated. The cold screen does not require welding during processing, making the process simple and the cold screen itself has high mechanical strength. Furthermore, the cold screen can be designed into different structural shapes based on the cooling effect and the need to shield stray light, further improving the accuracy of refrigerated infrared detection and showing good application prospects.

Description

Technical Field

[0001] The present invention relates to the field of infrared detection sensors, in particular to a cold screen and a refrigerated infrared detector with a wave-shaped integrated structure. Background Art

[0002] At present, infrared detection technology is widely used in various fields. It is mainly divided into two types: non-cooled infrared detectors and cooled infrared detectors. Cooled infrared detectors are the core components of infrared technology. Cooled infrared detectors usually include refrigerators, cold storage devices, cold plates, ceramic substrates, chips, cold screens and windows. Cooled infrared detectors are mainly used in night vision equipment, perimeter search, thermal imaging, forward warning, weapon guidance, air defense surveillance, infrared identification and other fields, and the requirements for the accuracy of cooled infrared detection are relatively high.

[0003] As a key component of a cooled infrared detector, the cold shield's primary function is to limit the field of view and suppress background radiation and stray light. The diameter of the opening at the top of the cold shield and its height determine the detector's F-number. The inner surface of the cold shield is blackened to absorb stray light reaching the chip, while the outer surface may be gold-plated or untreated. Because the cold shield is located at the farthest end of the cantilever beam, it experiences the greatest swing amplitude when the detector is subjected to vibration and impact. It is also the slowest heat transfer component in the entire cold head. When the detector chip cools to a workable temperature, the cold shield remains elevated, particularly at the top. This high-temperature area generates thermal radiation that is emitted onto the chip, affecting detector performance and imaging.

[0004] Existing cold shields are constructed by laser welding multiple thin-walled shells. This process can create risks such as cold welds, incomplete welds, and cracks, resulting in low mechanical strength. The cooling process of a cold shield involves transferring cooling energy from the bottom of the shield upwards, one level at a time. This inevitably creates gaps between adjacent cold shield levels, resulting in poor cooling performance and, consequently, failing to meet the accuracy requirements of certain high-precision infrared detection systems.

[0005] Therefore, there is an urgent need for a cold screen that increases the structural strength of the cold screen, shields stray light, and provides better cooling, so as to solve the technical problem in the existing technology that the performance indicators and imaging effects of infrared detectors are not high enough to meet the accuracy requirements. Summary of the Invention

[0006] In order to solve the problems existing in the prior art, according to one aspect of the present invention, the present invention provides the following technical solutions:

[0007] The present invention provides a cold screen with a wavy integrated structure. The side wall of the cold screen is a wavy structure, and the entire cold screen is formed in an integrated manner.

[0008] Furthermore, the cold screen includes a plurality of gradually contracting sections that gradually contract from bottom to top and a plurality of gradually expanding sections that gradually expand from bottom to top, and the positions where the gradually contracting sections intersect the gradually expanding sections above them form aperture holes.

[0009] Furthermore, the diameter of each aperture gradually decreases from bottom to top.

[0010] Furthermore, the inner surface of each of the tapered sections is gold-plated.

[0011] Furthermore, a blackened layer is provided on the inner surface of each of the gradually expanding sections.

[0012] Furthermore, the bottom of the cold shield is a vertical section, and the top of the vertical section is a tapered section.

[0013] Furthermore, the inner surface of the vertical segment is plated with gold.

[0014] Furthermore, the side wall of the cold shield is streamlined.

[0015] The invention provides a refrigeration type infrared detector. The refrigeration type infrared detector comprises a refrigerator, a cold storage device and a cold head. The cold head comprises a cold screen with a wavy structure.

[0016] The beneficial effects of the present invention compared to the prior art are as follows:

[0017] The present invention provides a novel, wavy, integrated cold shield. The entire cold shield is fabricated directly using a single electroforming process. The inner surface of the cold shield is blackened, while the outer surface can be gold-plated or untreated. Because the cold shield does not require welding during fabrication, the process is simple, the cold shield itself has high mechanical strength, and it offers excellent heat transfer and cooling performance. Furthermore, the cold shield can be designed into various shapes based on specific usage requirements. For enhanced stray light shielding, a large wavy shape can be used, increasing the number of undulations. For enhanced cooling performance, a small wavy shape can be used, reducing the number of undulations. The cold shield of the present invention features a simple manufacturing process, is easy to implement, and operates at a low cost. Subsequently, actual tests, comparisons, and analysis have shown that, under the same environmental parameters, a cooled infrared detector using the novel cold shield exhibits significantly higher structural strength and detection accuracy than a conventional cold shield. The infrared detector cold shield and infrared detector of the present invention, which offer improved cooling and stray light shielding, are suitable for high-precision infrared detection applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0019] Figure 1 This is a schematic diagram of the structure of the cold head of a refrigerated infrared detector;

[0020] Figure 2 This is a schematic diagram of the structure of the existing refrigerated infrared detector cold screen;

[0021] Figure 3 This is a schematic diagram of the structure of the cold screen with a wavy integrated structure of the present application;

[0022] Figure 4 This is a schematic structural diagram of another cold screen with a wavy integrated structure in the present application;

[0023] Figure 5 This is a structural diagram of the cold screen for this application.

[0024] Description of Figure Numbers:

[0025] 1-cold screen; 2-ceramic substrate; 3-cold plate; 4-chip; 5-cold finger cylinder; 6-cold finger base; 7-converging section; 8-expanding section; 9-vertical section; 10-gold plating layer; 11-blackening layer.

[0026] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0027] The following will be described clearly and completely in conjunction with the technical solutions in the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0028] The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the figures is not intended to limit the scope of the claimed invention, but rather merely represents selected embodiments of the present invention. All other embodiments derived by those skilled in the art based on the embodiments of the present invention without inventive effort are intended to be within the scope of protection of the present invention.

[0029] The components of the embodiments of the present invention generally described and shown in the drawings herein may be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention; if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back...), the directional indications are only used to explain the relative positional relationship, movement, etc. between the components under a certain specific posture (as shown in the drawings). If the specific posture changes, the directional indications also change accordingly.

[0030] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features specified as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that ordinary technicians in this field can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0031] The internal structure of the refrigerated infrared detector assembly Dewar in the prior art is as follows: Figure 1 As shown in the figure, the cold head part and the cold finger part form a cantilever beam structure, and the cold shield is at the farthest end of the cantilever beam. The cold head includes a cold shield 1, a ceramic substrate 2, a cold plate 3, and a chip 4. The cold shield 1 is placed on the ceramic substrate 2 and is located directly above the chip 4. The structural diagram of the cold shield is shown in the figure. Figure 2 As shown, the cold shield 1 is first electroformed from 0.1mm-thick nickel-cobalt material into a series of thin-walled semi-finished shells, which are then laser welded into the finished "pagoda"-shaped cold shield. The cold shield 1 is a thin-walled shell structure constructed by laser welding multiple thin-walled shells. This welding process can lead to risks such as cold welds, incomplete welds, and cracks, resulting in low mechanical strength. The cooling process of the cold shield 1 involves cooling energy from the bottom of the cold shield upwards layer by layer. Gaps inevitably exist between the contact surfaces of adjacent cold shields, resulting in poor cooling performance and, therefore, failing to meet the accuracy requirements of certain high-precision infrared detection applications.

[0032] The wavy integrated cold shield of the present invention is as follows Figure 3-5 As shown, Figure 3 、 4The entire cold shield is directly processed by a single electroforming process. The inner surface of the cold shield is blackened, and the outer surface of the cold shield can be gold-plated or untreated. The cold shield processing does not require welding, the processing technology is simple, the cold shield itself has high mechanical strength, and the heat transfer and cooling effect of the cold shield is good. Figure 3 In order to better shield stray light, the cold screen 1 is designed to have a large undulating shape and increase the number of undulations; Figure 4 In order to achieve better cooling, the cold screen 1 is designed to have a small undulating shape while reducing the number of undulations. Figure 5 This is a structural diagram of the cold screen for this application.

[0033] Example 1:

[0034] like Figure 3 and Figure 4 As shown, in this embodiment, the present invention provides a cold screen with a wavy integrated structure. The upper and lower ends of the cold screen 1 are open, the upper opening is used to install the filter, and the lower opening is generally installed on a ceramic substrate or a cold plate and other structures. The side wall of the cold screen 1 is a wavy structure, preferably a streamlined shape, that is, the corners are rounded, and there are no sharp edges. The entire cold screen is formed in one piece and can be processed by a one-time electroforming process. The processing technology is simple, the mechanical strength of the cold screen itself is high, and the heat transfer and cooling effect of the cold screen is good.

[0035] Refining the above embodiment, the cold shield 1 comprises multiple tapering sections 7 that taper from bottom to top, and multiple expanding sections 8 that expand from bottom to top. Both the tapering sections 7 and the expanding sections 8 are annular and arranged alternately from bottom to top and interconnected, forming a wavy structure. The inner diameter of each tapering section 7 is smaller at the intersection with the expanding section 8 above it, forming an aperture that suppresses stray light. Preferably, the diameter of each aperture decreases from bottom to top, enhancing the stray light suppression effect. Furthermore, preferably, the bottom of the cold shield is a vertical section 9, within which the chip 4 is mounted. This vertical section has a consistent inner diameter from bottom to top, and above the vertical section 9 is the tapered section 7. This structure results in a larger diameter at the bottom of the cold shield, providing greater stability during installation and facilitating verticality. Furthermore, the vertical section 9 and the tapered section 7 above it enclose the chip 4, effectively locking in the low-temperature field around the chip 4 and facilitating rapid startup of the detector. A light-blocking ring structure may also be formed on the upper end of the cold shield 1 to better suppress stray light. The inner surface of the cold shield 1 may be provided with a blackened layer, and the outer surface may be provided with a gold-plated layer or left untreated.

[0036] The cold screen of the wavy integrated structure of the present invention can also be designed into different wavy structures according to different needs. Figure 3In order to better shield stray light, the cold screen 1 is designed to have a large undulating shape, and the number of undulations is increased. Preferably, the number of aperture holes is at least three. Figure 4 In order to achieve better cooling, the cold screen 1 is designed to have a small undulating shape while reducing the number of undulations. Preferably, the number of aperture holes does not exceed two.

[0037] Example 2:

[0038] like Figure 5 As shown, in this embodiment, the present invention provides a cold shield with a wavy, integrated structure. This differs from the first embodiment in that the inner surface of each tapered segment 7 is provided with a gold-plated layer 10. Since the tapered segment 7 directly faces the chip 4, the thermal radiation generated by it can directly reach the chip 4 and interfere with it. By providing the gold-plated layer 10 on the inner surface of the tapered segment 7, gold has a low emissivity, which can reduce the interference of thermal radiation emitted from the tapered segment 7 to the chip 4. Preferably, the inner surface of each expanding segment 7 is provided with a blackened layer 11 with a high emissivity, which is used to absorb stray light entering the cold shield 1. Since the chip 4 is mounted within the vertical segment 9, the thermal radiation from the vertical segment 9 significantly affects the chip 4. Therefore, the gold-plated layer 10 can also be provided on the inner surface of the vertical segment 9.

[0039] Example 2:

[0040] The present invention provides a refrigerated infrared detector, which includes a refrigerator, a cold storage device and a cold head. The cold head includes a cold screen with a wavy structure. The cold screen can adopt the cold screen structure of embodiment one or embodiment two, and the specific structure is not repeated here.

[0041] The novel cold shield structure employed in this invention is a wavy, integrated cold shield. The entire shield is fabricated directly using a single electroforming process. The inner surface is blackened, while the outer surface can be gold-plated or untreated. Because the cold shield in this patented invention does not require welding, the process is simple, the shield itself has high mechanical strength, and it offers excellent heat transfer and cooling performance. Furthermore, the cold shield can be designed into various shapes to suit specific applications. For enhanced stray light shielding, a large wavy shape can be used, increasing the number of undulations. For enhanced cooling performance, a small wavy shape can be used, reducing the number of undulations. The cold shield of this invention features a simple manufacturing process, easy implementation, and convenient operation at a low cost. Subsequently, actual tests, comparisons, and analysis revealed that, under the same environmental parameters, a cooled infrared detector using the novel cold shield exhibited significantly higher structural strength and detection accuracy than a conventional cold shield. The infrared detector cold shield and infrared detector of this invention, which offer improved cooling and stray light shielding, are suitable for high-precision infrared detection applications.

[0042] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention specification under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A cold shield with a wave-shaped integrated structure, characterized in that: The side wall of the cold screen is a wavy structure, and the entire cold screen is formed in one piece; the cold screen includes multiple tapering sections that gradually shrink from bottom to top and multiple expanding sections that gradually expand from bottom to top, and an aperture hole is formed at the intersection of the tapering section and the expanding section above it.

2. The cold shield with a wave-shaped integrated structure according to claim 1, characterized in that: The diameter of each aperture gradually decreases from bottom to top.

3. The cold shield with a wave-shaped integrated structure according to claim 1, characterized in that: The inner surface of each tapered section is gold-plated.

4. The cold shield with a wave-shaped integrated structure according to claim 3, characterized in that: The inner surface of each gradually expanding section is provided with a blackened layer.

5. The cold shield with a wave-shaped integrated structure according to claim 1, characterized in that: The bottom of the cold screen is a vertical section, and the top of the vertical section is a tapered section.

6. The cold shield with a corrugated integrated structure according to claim 5, characterized in that: The inner surface of the vertical segment is plated with gold.

7. The cold shield with a wave-shaped integrated structure according to claim 1, characterized in that: The outer surface of the cold screen is gold-plated.

8. The cold shield with a wave-shaped integrated structure according to claim 1, characterized in that: The side wall of the cold shield is streamlined.

9. A refrigerated infrared detector, characterized in that: The refrigerated infrared detector comprises a refrigerator, a cold storage device and a cold head, wherein the cold head comprises a cold shield with a wavy integrated structure as claimed in any one of claims 1 to 8.

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