A light window device for vacuum low-temperature cold box or Dewar and its manufacturing method

Abstract

The present invention discloses an optical window device for a vacuum cryogenic cold box or dewar and a method for manufacturing the same, suitable for vacuum airtight fixation of coated optical components. The present invention primarily comprises a color separation plate, a mounting frame, and metal solder. By introducing a specific structure, optimizing the process, and performing process treatments, the color separation plate is airtightly fixed as an optical window in a vacuum cryogenic cold box or dewar. This also addresses the issue of the optical performance of the color separation plate being affected by the airtight mounting and fixing of the metal frame in the vacuum cryogenic cold box or dewar. The present invention has a simple structure, convenient operation, good compatibility, and high reliability. It can be applied to various low-stress airtight fixation processes for optical thin film components and metal frames.

Description

Technical Field

[0001] The present invention relates to a hermetic packaging technology for optical components 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 components. Background Art

[0002] Traditional area array infrared detection systems feature high sensitivity, high two-dimensional spatial resolution, and a wide dynamic range when equipped with a two-dimensional turntable. They enable autonomous target search and tracking in complex environments and are highly resistant to electromagnetic interference. However, infrared imaging only captures two-dimensional information about the target, failing to accurately determine its range and velocity. Combining passive infrared imaging with active laser detection creates an infrared / laser dual-mode hybrid detection system, providing three-dimensional angle-angle-range information. This data can then be integrated with high-speed information processing systems to extract target velocity and trajectory information through data fusion. The hybrid infrared imaging and active laser detection technology leverages the strengths of both technologies to offset their respective shortcomings. First, infrared imaging rapidly detects and locates targets within a large field of view. Then, active laser detection acquires high-resolution intensity and range images of suspected targets, enabling real-world and fake-target identification. Multi-sensor data fusion provides optimal overall information support for decision-making.

[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, the color separation plate as the light window of a vacuum low-temperature cold box or Dewar becomes a demand. The color separation plate 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 plate, or the impact of installation and fixation at low temperatures on the optical performance of the color separation plate. Using the color separation plate 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 plate on the optical performance of the color separation plate. There are no reports of using the color separation plate as the light window of a vacuum low-temperature cold box or Dewar at home and abroad. There is an urgent need to solve the problem of airtight packaging of the color separation plate 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 Dewar and a manufacturing method thereof, which solves the problems of the prior art in which airtight welding affects the optical performance of the color separation film, and the airtight installation and fixation of the metal frame on the vacuum low-temperature cold box or Dewar affects 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 stepped, and a first step folded inward is provided on the lower surface of the edge of the color separation sheet. The inner edge of the mounting frame is also stepped accordingly, and a second step folded inward is provided 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 provided above 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] The upper surface of the installation frame is also provided with a recessed heat insulation groove.

[0009] A fourth step is provided 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 and fourth steps on the edge of the color separation film, then optically polish and metallize the edge of the color separation film; nickel-plate 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: Perform secondary optical processing on the upper and lower surfaces of the color separation plate 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: Perform a leak test on the light window device for the vacuum low-temperature cold box or Dewar after completing step 4;

[0018] Step 6: Install the optical window device for the vacuum low temperature cold box or Dewar that has passed the leak test in step 5 on the vacuum low temperature cold box or Dewar, and use laser airtight welding to airtightly fix it 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 problem of the influence of the color separation plate welding structure and welding heat on the optical performance of the color separation plate by first air-tightly welding the color separation plate bare chip to the mounting frame and then coating the color separation plate; 3. The heat insulation groove on the upper surface of the mounting frame solves the problem of the influence of subsequent laser air-tight welding on the optical performance of the color separation plate; 4. The present invention can also be applied to the 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 structural schematic diagram of the present invention;

[0021] Figure 2 It is attached Figure 1 Enlarged schematic diagram of the circled part;

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

[0023] The present invention will be further described below with reference to the accompanying drawings, which are for illustrative purposes only and are not to be construed as limiting the present invention.

[0024] To more concisely illustrate this embodiment, some components well known to those skilled in the art but not relevant to the main content of this invention may be omitted from the drawings or descriptions. In addition, for ease of description, some components may be omitted, enlarged, or reduced in size in the drawings, but they do not represent the dimensions 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. The inner edge of the mounting frame 2 is also stepped accordingly, and the lower edge of the inner side of the mounting frame 2 is provided with a second step 21 folded inward. 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 above the second step 21. The gap between the edge of the color separation sheet 1 and the third step 22 is a solder cavity 3 for placing solder. The color separation sheet 1 is fixed to the mounting frame 2 by solder. The solder is a gold-tin alloy with the molecular formula 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, so that the solder can flow into the process groove 24 without overflowing. The process groove 24 has a width of 0.5 mm to 1 mm and a depth of 1 mm to 2 mm.

[0027] The upper surface of the mounting frame 2 is further provided with a recessed heat-insulating groove 23 to prevent the color separation film 1 from being affected by heat generated when the light 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 edge of the color separation plate 1 to facilitate welding of the color separation plate 1 and the mounting frame 2. The upper surface of the color separation plate 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 manufacturing method of the light window device for a vacuum low-temperature cold box or a Dewar as described above comprises the following steps:

[0031] Step 1: Process the first step 11 and the fourth step 12 on the edge of the color separation plate 1, with a step width of about 2mm-3mm; then optically polish the edge of the color separation plate 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: Perform secondary optical processing on the upper and lower surfaces of the color separation plate 1 to meet optical requirements;

[0035] Step 4: coating the color separation sheet 1 that has undergone the secondary optical processing in step 3 with an optical film;

[0036] Step 5: Perform a leak test on the light window device for the vacuum low-temperature cold box or Dewar after completing step 4;

[0037] Step 6: Install the optical window device for the vacuum low temperature cold box or Dewar that has passed the leak test in step 5 on the vacuum low temperature cold box or Dewar, and use laser airtight welding to airtightly fix it 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 of the present invention should fall within the technical scope of the present invention.

Claims

1. A method for manufacturing a light window device for a vacuum low-temperature cold box or a Dewar, the light window device comprising a color separation sheet (1) and a mounting frame (2); the edge of the color separation sheet (1) is stepped, the lower surface of the edge of the color separation sheet (1) is provided with a first step (11) folded inwardly, the inner edge of the mounting frame (2) is also correspondingly stepped, the lower edge of the inner side of the mounting frame (2) is provided with a second step (21) folded inwardly, 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 above the second step (21), 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; A recessed process groove (24) is provided at the transition between the second step (21) and the third step (22); The upper surface of the mounting frame (2) is further provided with a recessed heat-insulating groove (23); 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 mounting frame (2); The edge of the color separation sheet (1) is optically polished and then metallized, and the mounting frame (2) is a metal frame that is nickel-plated; The solder is a gold-tin alloy with the molecular formula AuSn 20 ; Its characteristics are: The steps for making the light window device 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) that has undergone secondary optical processing in step 3 with an optical film; Step 5: Perform a leak test on the light window device for the vacuum low-temperature cold box or Dewar after completing step 4; Step 6: Install the optical window device for the vacuum cryogenic cold box or dewar that has passed the leak test in step 5 on the vacuum cryogenic cold box or dewar, and fix it on the vacuum cryogenic cold box or dewar through laser airtight welding.

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