Light window device for vacuum low-temperature cold box or Dewar and manufacturing method of light window device

Abstract

The invention discloses an optical window device for a vacuum low-temperature cold box or Dewar and a manufacturing method of the optical window device. The optical window device is suitable for vacuum airtight fixation of a coated optical element. According to the invention, the airtight fixation of the color separation sheet as a light window of a vacuum low-temperature cold box or Dewar is realized mainly by introducing a specific structure, flow optimization and process treatment through the color separation sheet, the mounting frame and the metal solder. Meanwhile, the problem that the optical performance of the color separation piece is affected due to the fact that a metal frame is installed and fixed on a vacuum low-temperature cold box or a Dewar in an airtight mode is solved. The device is simple in structure, convenient to operate, good in compatibility and high in reliability. The method can be applied to various low-stress airtight fixing processes of elements with optical thin films and metal frames.

Description

Technical Field

[0001] The invention relates to a hermetic packaging technology for optical elements with films, and in particular to an optical window device for a vacuum low-temperature cold box or a Dewar and a manufacturing method thereof, which is suitable for vacuum airtight fixation of coated optical elements. Background Art

[0002] Traditional array infrared detection has the characteristics of high sensitivity, high two-dimensional spatial resolution and large dynamic range after being equipped with a two-dimensional turntable. It can realize autonomous search and tracking of targets in complex environments and has strong anti-electromagnetic interference capabilities. However, infrared imaging can only obtain two-dimensional information of the target, and cannot obtain accurate distance and speed information of the target. Combining infrared passive imaging and laser active detection to form infrared / laser dual-mode composite detection, the three-dimensional information of angle-angle-distance of the target is obtained, and the data fusion can be used with a high-speed information processing system to extract the target speed and trajectory information. The use of infrared imaging and laser active detection composite technology can give full play to the advantages of both and make up for their respective shortcomings. First, infrared imaging is used to quickly detect and locate the target in a larger field of view, and then laser active detection is used to obtain high-resolution intensity images and distance images of suspected targets to realize the identification of true and false targets. And based on the fusion of multi-sensor data, the overall information can be given the greatest information guarantee to make decisions.

[0003] In response to the demand for higher miniaturization and integration, infrared array detection systems sometimes need to rely on cold optical systems to provide detection sensitivity and reduce background radiation. In this way, it becomes a demand to use the color separation film as the light window of a vacuum low-temperature cold box or Dewar. The color separation film in the traditional optical system design is to achieve optical semi-transmission and semi-reflection in two bands. When applied, the main consideration is the fixed adjustment of the color separation film, or the impact of installation and fixation at low temperatures on the optical properties of the color separation film. Using the color separation film as the light window of a vacuum low-temperature cold box or Dewar involves the impact of the airtight welding and fixation of the color separation film on the optical properties of the color separation film. There are no reports of using the color separation film as the light window of a vacuum low-temperature cold box or Dewar at home and abroad. It is urgent to solve the problem of airtight packaging of the color separation film and the metal frame. Summary of the invention

[0004] The purpose of the present invention is to provide an optical window device for a vacuum low-temperature cold box or a Dewar and a manufacturing method thereof, which solves the problem of the influence of the airtight welding in the prior art on the optical performance of the color separation film, and the influence of the airtight installation and fixation of the metal frame on the vacuum low-temperature cold box or the Dewar on the optical performance of the color separation film.

[0005] To achieve the above object, the technical solution of the present invention is:

[0006] A light window device for a vacuum low-temperature cold box or a Dewar comprises a color separation sheet and a mounting frame; the edge of the color separation sheet is in a stepped shape, a first step folded inwardly is arranged on the lower surface of the edge of the color separation sheet, the inner edge of the mounting frame is also correspondingly arranged in a stepped shape, a second step folded inwardly is arranged on the lower edge of the inner side of the mounting frame, the first step of the color separation sheet is mounted on the second step of the mounting frame; a third step is arranged on the second step, the gap between the edge of the color separation sheet and the third step is a solder cavity for placing solder, and the color separation sheet is fixed to the mounting frame by the solder.

[0007] A recessed process groove is provided at the transition between the second step and the third step.

[0008] A recessed heat-insulating groove is also provided on the upper surface of the installation frame.

[0009] A fourth step is arranged on the upper surface of the edge of the color separation sheet, and the upper surface of the color separation sheet is higher than the upper surface of the installation frame.

[0010] The edges of the color separation film are optically polished and then metalized, and the mounting frame is a metal frame that is nickel-plated.

[0011] The solder is a gold-tin alloy with the molecular formula AuSn 20 .

[0012] The manufacturing method of the light window device for a vacuum low temperature cold box or a Dewar as described above has the following manufacturing steps:

[0013] Step 1: Process the first step and the fourth step of the edge of the color separation film, then optically polish the edge of the color separation film and perform metallization; nickel-plating the mounting frame;

[0014] Step 2: eutectic welding the mounting frame and the edge of the color separation sheet, and perform airtightness leak detection under a special fixture;

[0015] Step 3, performing secondary optical processing on the upper and lower surfaces of the color separation film to meet optical requirements;

[0016] Step 4, coating the color separation sheet after the secondary optical processing in step 3 with an optical film;

[0017] Step 5, performing airtightness leak detection again on the light window device for vacuum low temperature cold box or Dewar after completing step 4;

[0018] Step six, install the optical window device for the vacuum low temperature cold box or dewar that has passed the leak test in step five on the vacuum low temperature cold box or dewar, and use laser airtight welding to make it airtightly fixed on the vacuum low temperature cold box or dewar.

[0019] The advantages of the present invention are: 1. Simple structure, easy operation and low cost; 2. The present invention solves the influence of the color separation sheet welding structure and welding heat on the optical performance of the color separation sheet by first air-tight welding the color separation sheet bare chip and the mounting frame and then coating the film; 3. The heat insulation groove on the upper surface of the mounting frame solves the influence of subsequent laser air-tight welding on the optical performance of the color separation sheet; 4. The present invention can also be applied to low-stress air-tight fixation of various other optical film components and metal frames. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structure of the present invention;

[0021] Figure 2 Yes Figure 1 Enlarged schematic diagram of the circled part;

[0022] In the figure: 1-color separation sheet; 11-first step; 12-fourth step; 2-installation frame; 21-second step; 22-third step; 23-insulation groove; 24-process groove; 3-solder cavity. DETAILED DESCRIPTION

[0023] The present invention is further described below in conjunction with the accompanying drawings, which are only used for exemplary description and cannot be understood as limiting the present invention.

[0024] In order to more concisely describe the present embodiment, some parts known to those skilled in the art but not related to the main content of the present invention are omitted in the drawings or descriptions. In addition, for the convenience of description, some parts in the drawings are omitted, enlarged or reduced, but they do not represent the size or entire structure of the actual product.

[0025] The present invention discloses a light window device for a vacuum low temperature cold box or a Dewar, such as Figure 1 , 2 As shown, it includes a color separation sheet 1 and a mounting frame 2; the edge of the color separation sheet 1 is stepped, and the lower surface of the edge of the color separation sheet 1 is provided with a first step 11 folded inward, and the inner edge of the mounting frame 2 is also correspondingly provided with a stepped shape, and the lower edge of the inner side of the mounting frame 2 is provided with a second step 21 folded inward, and the first step 11 of the color separation sheet 1 is mounted on the second step 21 of the mounting frame 2; a third step 22 is provided on the second step 21, and the gap between the edge of the color separation sheet 1 and the third step 22 is a solder cavity 3 for placing solder, and the color separation sheet 1 is fixed to the mounting frame 2 by solder. The solder is a gold-tin alloy, and the molecular formula is AuSn 20 .

[0026] Preferably, to prevent the overflow of solder during the soldering process, Figure 2As shown, a concave process groove 24 is provided at the transition between the second step 21 and the third step 22, and the solder can flow into the process groove 24 without overflowing. The width of the process groove 24 is 0.5mm-1mm, and the depth is 1mm-2mm.

[0027] The upper surface of the mounting frame 2 is also provided with a recessed heat-insulating groove 23 to prevent the color separation sheet 1 from being affected by heat generated when the optical window device of the present invention is laser welded in a vacuum low-temperature cold box or a Dewar.

[0028] Furthermore, a fourth step 12 is provided on the upper surface of the edge of the color separation sheet 1, so as to facilitate the operation of welding the color separation sheet 1 and the mounting frame 2. The upper surface of the color separation sheet 1 is higher than the upper surface of the mounting frame 2.

[0029] Before the color separation sheet 1 and the mounting frame 2 are welded, the edge of the color separation sheet 1 is optically polished and then metallized. The mounting frame 2 is a metal frame and is nickel-plated.

[0030] The method for making the light window device for a vacuum low temperature cold box or a Dewar as described above has the following steps:

[0031] Step 1: Process the first step 11 and the fourth step 12 of the edge of the color separation sheet 1, with a step width of about 2mm-3mm; then optically polish the edge of the color separation sheet 1 and metallize it; the thickness and firmness of the metallization layer meet the requirements of eutectic welding.

[0032] At the same time, the mounting frame 2 is nickel plated, and the thickness and firmness of the nickel layer meet the requirements of surface treatment and airtight welding.

[0033] Step 2: eutectic welding the mounting frame 2 and the edge of the color separation sheet 1, and perform airtightness leak detection under a special fixture to ensure that the airtightness meets the requirements.

[0034] Step 3, performing secondary optical processing on the upper and lower surfaces of the color separation sheet 1 to meet optical requirements;

[0035] Step 4, coating the color separation sheet 1 after the secondary optical processing in step 3 with an optical film;

[0036] Step 5, performing airtightness leak detection again on the light window device for vacuum low temperature cold box or Dewar after completing step 4;

[0037] Step six, install the optical window device for the vacuum low temperature cold box or dewar that has passed the leak test in step five on the vacuum low temperature cold box or dewar, and use laser airtight welding to make it airtightly fixed on the vacuum low temperature cold box or dewar.

[0038] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. That is, any equivalent changes and modifications made according to the content of the patent application scope of the present invention should be within the technical scope of the present invention.

Claims

1. A light window device for a vacuum low-temperature cold box or a Dewar, comprising a color separation sheet (1) and a mounting frame (2); characterized in that: The edge of the color separation sheet (1) is in a stepped shape, a first step (11) folded inwardly is arranged on the lower surface of the edge of the color separation sheet (1), the inner edge of the mounting frame (2) is also correspondingly arranged in a stepped shape, a second step (21) folded inwardly is arranged on the lower edge of the inner side of the mounting frame (2), the first step (11) of the color separation sheet (1) is mounted on the second step (21) of the mounting frame (2); a third step (22) is arranged on the second step (21), a gap between the edge of the color separation sheet (1) and the third step (22) is a solder cavity (3) for placing solder, and the color separation sheet (1) is fixed to the mounting frame (2) by solder.

2. The light window device for a vacuum low temperature cold box or a Dewar according to claim 1, characterized in that: A recessed process groove (24) is provided at the transition between the second step (21) and the third step (22).

3. The light window device for a vacuum low temperature cold box or a Dewar according to claim 2, characterized in that: The upper surface of the installation frame (2) is also provided with a recessed heat insulation groove (23).

4. The light window device for a vacuum low temperature cold box or a Dewar according to claim 3, characterized in that: A fourth step (12) is provided on the upper surface of the edge of the color separation sheet (1), and the upper surface of the color separation sheet (1) is higher than the upper surface of the installation frame (2).

5. The light window device for a vacuum low temperature cold box or a Dewar according to claim 4, characterized in that: The edge of the color separation sheet (1) is optically polished and then metallized, and the mounting frame (2) is a metal frame and is nickel-plated.

6. The light window device for a vacuum low temperature cold box or a Dewar according to claim 5, characterized in that: The solder is a gold-tin alloy with the molecular formula AuSn 20 .

7. The method for manufacturing the light window device for a vacuum low temperature cold box or a Dewar according to claim 6, characterized in that: The production steps are as follows: Step 1: Processing the first step (11) and the fourth step (12) on the edge of the color separation sheet (1), then optically polishing the edge of the color separation sheet (1), and metallizing the same; nickel-plating the mounting frame (2); Step 2: eutectic welding the mounting frame (2) and the edge of the color separation sheet (1), and performing airtightness leak detection under a special fixture; Step 3, performing secondary optical processing on the upper and lower surfaces of the color separation sheet (1) to meet optical requirements; Step 4, coating the color separation sheet (1) after the secondary optical processing in step 3 with an optical film; Step 5, performing airtightness leak detection again on the light window device for vacuum low temperature cold box or Dewar after completing step 4; Step six, install the optical window device for the vacuum low temperature cold box or dewar that has passed the leak test in step five on the vacuum low temperature cold box or dewar, and use laser airtight welding to make it airtightly fixed on the vacuum low temperature cold box or dewar.

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