Split type cold shield for infrared detector and assembling method thereof

Abstract

This invention provides a split-type cold screen for an infrared detector and its assembly method. The split-type cold screen for the infrared detector includes a cold screen body and matte fins. The assembly method includes: applying a black coating to both the cold screen body and the matte fins, pre-baking them, then initially assembling the pre-baked cold screen body and the matte fins, and finally baking the pre-assembled cold screen to complete the assembly. This invention places the cold screen assembly step after pre-baking and before baking, using the bonding force of the black coating to connect the cold screen body and the matte fins. This eliminates the adhesive bonding step in the split-type cold screen assembly process, solving the problem of using adhesives to bond the cold screen body and matte fins in the split-type cold screen assembly process. This ensures good mechanical reliability of the cold screen assembly in low-temperature vibration environments and also improves the performance of the detector components and the efficiency of the cold screen assembly process.

Description

Technical Field

[0001] This invention relates to the field of infrared detector Dewar assembly technology, and in particular to a split-type cold screen for an infrared detector and its assembly method. Background Technology

[0002] The cold screen is the optical component of a cooled infrared detector micro-Dewar, located directly above the chip. It consists of a main body and several extinction fins. The main body is made of thin-walled metal with a metal plating on the outer surface and a thin black coating on the interior and top areas. Structurally, the main body has several through-holes and positioning structures. The extinction fins are thin metal plates fixed to the main body, with optical openings in the center and a uniform thin black coating on their surface. The function of the cold screen is to provide a low-temperature operating environment for the filters mounted on top, limit the light path, absorb internal stray light, and reduce background noise in the detector imaging.

[0003] Traditional cold screen assembly processes involve five steps: cleaning, applying protective adhesive, blackening treatment, removing protective adhesive, and cold screen assembly and bonding. Here, blackening treatment refers to applying a black coating to the surface of the cold screen components and then pre-baking and baking for a certain period. Cold screen assembly and bonding refers to using adhesive to bond the cold screen body and the matting fins. Cold screen assembly and bonding suffers from the problem of high adhesive usage, which has a strong negative impact on detector component performance and assembly process efficiency. The high reflectivity of the adhesive overflow surface at the bonding area between the cold screen body and the matting fins increases stray light reflection within the cold screen. Furthermore, the adhesive slowly releases small molecule gases, such as H2 and CO2, in a high vacuum environment, shortening the vacuum life of the micro Dewar. The long curing time of the adhesive is also a significant reason for the low efficiency of the cold screen assembly process. Therefore, an ideal cold screen assembly process should reduce or eliminate the use of adhesive.

[0004] To control the use of adhesives while meeting the assembly requirements of the matting fins and the cold screen body, existing technology discloses an integrated cold screen molding method for infrared detectors. This technology directly electroforms the matting fins of the cold screen to the cold screen body, avoiding secondary bonding and effectively controlling the amount of adhesive used for encapsulation. However, this method results in a long processing cycle for cold screen parts, and because the cold screen has blind spots, it is impossible to inspect and clean burrs and other imperfections on the surface of the cold screen in these areas. Summary of the Invention

[0005] This invention addresses the problems in existing technologies where adhesives are used to bond the cold screen body and matting fins during the assembly of separate cold screens, leading to excessively long assembly times, increased stray light reflection within the cold screen, and shortened micro Dewar lifespan. This invention provides a separate cold screen for infrared detectors and its assembly method. It utilizes the black coating used in the cold screen blackening process as the connector between the cold screen body and the matting fins, eliminating the adhesive bonding step in the separate cold screen assembly process. This ensures the mechanical reliability of the cold screen assembly in low-temperature vibration environments and improves detector component performance and cold screen assembly process efficiency.

[0006] The present invention provides a method for assembling a split-type cold screen for infrared detectors. After applying a black coating to the main body of the cold screen and the matte fins of the split-type cold screen, they are first pre-baked, then the pre-baked main body of the cold screen and the matte fins are initially assembled, and finally the initially assembled cold screen is baked to complete the cold screen assembly.

[0007] According to some embodiments of the present invention, before applying the black coating to the cold screen body and the matte fins, the cold screen body and the matte fins are cleaned, and protective adhesive is applied to the parts of the cold screen body that do not need to be blackened.

[0008] According to some embodiments of the present invention, the method for applying a black coating to the cold screen body and the matte fins is electrophoretic blackening or spray blackening.

[0009] According to some embodiments of the present invention, the first preset temperature for pre-baking the cold screen body and the matte fins is 25°C to 150°C.

[0010] According to some embodiments of the present invention, the cold screen body and the matte fins are initially assembled after pre-baking.

[0011] According to some embodiments of the present invention, the second preset temperature for baking the pre-assembled cold screen is 50°C to 400°C.

[0012] According to some embodiments of the present invention, the protective adhesive on the surface of the cold screen body is removed after baking.

[0013] The present invention provides a split-type cold screen for an infrared detector, comprising a cold screen body and an anti-glare fin, which is assembled using the above-described split-type cold screen assembly method for an infrared detector.

[0014] This invention solves the problem of using adhesives to bond the cold screen body and matte fins in the separate cold screen assembly process. It utilizes a black coating as the connector between the cold screen body and the matte fins, placing the cold screen assembly step after pre-baking and before baking. This eliminates the adhesive bonding step in the separate cold screen assembly process, ensuring good mechanical reliability of the cold screen assembly in low-temperature vibration environments. It also improves the performance of the detector components and the efficiency of the cold screen assembly process. Its specific beneficial effects include:

[0015] 1. The cold screen assembly has a simple structure, and the excellent mechanical properties of the black coating enable the cold screen to maintain excellent reliability in low-temperature vibration environments.

[0016] 2. It eliminates the three processes of adhesive preparation, coating, and curing in the cold screen assembly and bonding process, saving 8-24 hours of labor time and effectively improving process efficiency.

[0017] 3. It avoids secondary gluing during the cold screen assembly process, effectively controls the amount of adhesive used, and helps to improve the vacuum life of the infrared detector.

[0018] 4. The absence of highly reflective areas within the cold screen helps reduce stray light within the cold screen and lowers the background noise in detector imaging. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a split-type cold screen assembly for an infrared detector based on existing technology.

[0020] Figure 2 This is a schematic diagram of a split-type cold screen assembly for an infrared detector according to an embodiment of the present invention.

[0021] Figure Labels

[0022] Split-type cooling screen 10,

[0023] Vent 111, positioning structure 112,

[0024] Matte fin 120,

[0025] Black coating 130,

[0026] Adhesive 140. Detailed Implementation

[0027] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments.

[0028] The present invention provides a method for assembling a split-type cold screen 10 for an infrared detector. After applying a black coating 130 to the cold screen body and the matting fins 120 of the split-type cold screen 10, they are pre-baked. Then, the pre-baked cold screen body and the matting fins 120 are initially assembled. Finally, the initially assembled cold screen is baked to complete the assembly. The cold screen body has several through-holes 111 and a positioning structure 112. The positioning structure 112 is a physical structure that facilitates the precise assembly of the cold screen body and the matting fins; it is located on the cold screen body and comes in various forms.

[0029] In traditional processes, the main body of the split-type cold screen 10 and the matte fins 120 are respectively blackened. Blackening involves applying a black coating 130 to the surface of the cold screen components and then pre-baking and baking for a certain period. After blackening, adhesive 140 is used to bond the main body of the cold screen and the matte fins 120 together. Figure 1 As shown. This invention breaks down the blackening process into three main steps: black coating 130 adhesion, pre-baking, and baking. The initial assembly of the cold screen body and the matte fins 120 is placed after the pre-baking step. Thus, the black coating 130 serves as the connector between the cold screen body and the matte fins 120, eliminating the adhesive 140 bonding step in the assembly process of the split cold screen 10. Figure 2 As shown.

[0030] The black coating 130 applied to the cold screen can maintain excellent mechanical reliability in low-temperature vibration environments without peeling or flaking off. The method of the present invention uses the bonding force of the black coating 130 to connect the cold screen body and the matting fins 120, effectively eliminating the negative impact of the adhesive 140 in the prior art on the performance of the detector components and the efficiency of the assembly process.

[0031] According to some embodiments of the present invention, the method for attaching a black coating 130 to the cold screen body and the matte fins 120 is electrophoretic blackening or spray blackening, and different blackening processes affect the subsequent pre-baking as well as the baking temperature and duration. Figure 1 or Figure 2 As shown, the main body of the cold screen is a thin-walled metal material, and a black coating 130 is applied to the interior and top partial areas of the main body of the cold screen; the matte fins 120 are thin metal plates fixed on the main body of the cold screen, with an optical opening in the center, and the black coating 130 is evenly applied to the surface of the matte fins.

[0032] According to some embodiments of the present invention, the first preset temperature for pre-baking the cold screen body and the matte fins 120 is 25°C to 150°C. In actual operation, the pre-baking time varies depending on the properties of different black coatings 130. After pre-baking, the surface of the black coating 130 is set and does not affect the assembly operation of the cold screen body and the matte fins 120.

[0033] According to some embodiments of the present invention, the second preset temperature for baking the pre-assembled cold screen is 50°C to 400°C. In actual operation, the baking time varies depending on the properties or adhesion methods of the different black coatings 130. During high-temperature baking, the black coatings 130 in contact with the surfaces of the cold screen body and the matte fins 120 undergo physicochemical reactions such as melting and solidification, bonding the cold screen body and the matte fins 120 together to complete the final assembly.

[0034] According to some embodiments of the present invention, the protective adhesive on the surface of the cold screen body is removed after baking.

[0035] The present invention provides a split-type cold screen 10 for infrared detectors, comprising a cold screen body and an extinction fin 120, which is assembled using the above-described assembly method for split-type cold screen 10 for infrared detectors.

[0036] This document introduces a specific embodiment of an assembly method for a split-type cold screen 10 for an infrared detector. The specific method includes:

[0037] Step 1: Clean the cold screen components and apply protective adhesive, including cleaning the cold screen body and matte fins 120, and applying protective adhesive to the cleaned cold screen body to protect the parts that do not need to be blackened.

[0038] Step 2: Apply a black coating 130 to the corresponding positions of the cold screen body and the matte fins 120 using methods such as electrophoretic blackening or spray blackening. Figure 2 As shown;

[0039] Step 3: Place the cold screen body with the black coating 130 and the matte fins 120 in an environment of 10℃~150℃ for a certain period of time for pre-baking.

[0040] Step 4: Initially assemble the pre-baked matte fins 120 onto the pre-baked cold screen body;

[0041] Step 5: Place the pre-assembled cold screen in an environment of 50℃~400℃ and bake for a certain period of time.

[0042] Step 6: After baking, remove the protective adhesive from the surface of the cold screen body. The cold screen assembly process is now complete.

[0043] Through the description of specific embodiments, a more in-depth and specific understanding should be gained of the technical means and effects adopted by the present invention to achieve the intended purpose. However, the accompanying drawings are only for reference and illustration and are not intended to limit the present invention.

Claims

1. A method for assembling a split-type cold screen for an infrared detector, characterized in that, include: The main body of the cold screen and the matte fins are cleaned, and protective glue is applied to the parts of the cold screen that do not need to be blackened. A black coating is applied to the main body of the split-type cold screen and the matte fins, respectively, and they are pre-baked. The pre-baked cold screen body and the matte fins are initially assembled using the pre-baked black coating. The pre-assembled split-type cold screen is then baked to complete the assembly. The method for applying a black coating to the main body of the cold screen and the matte fins is electrophoretic blackening or spray blackening; The first preset temperature range for pre-baking the cold screen body and the matte fins is 25℃~150℃; The second preset temperature range for baking the pre-assembled cold screen is 50℃~400℃.

2. The method for assembling a split-type cold screen for an infrared detector as described in claim 1, characterized in that, After baking the split-type cold screen, the method further includes removing the protective adhesive from the surface of the cold screen body.

3. A split-type cold screen for an infrared detector, characterized in that, include: The main body of the cold screen and the matting fins are assembled using the split-type cold screen assembly method for infrared detectors as described in any one of claims 1-2.

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