CN-122018104-A - Low-stress mounting structure of optical window

CN122018104ACN 122018104 ACN122018104 ACN 122018104ACN-122018104-A

Abstract

The invention discloses a low-stress mounting structure of an optical window, which comprises the optical window, a window inner frame, a window ring, a transition frame and a window outer frame, wherein the lower end of the optical window is hermetically welded with the window inner frame, the upper end of the optical window is welded with the window ring, and the transition frame is hermetically welded with the window inner frame after being welded with the window outer frame. The stress balance of the upper end face and the lower end face in the optical window welding is utilized to ensure the quality of the surface of the welded window, and the transition frame thin-wall structure is utilized to physically isolate the light material of the outer frame of the window in the heat expansion and cold contraction and structural deformation, so that the stress isolation effect of the optical window is realized.

Inventors

JIANG MENGDIE
XU LIN
YU JUN
SHEN YIZHANG
SUN WEN
MO DEFENG

Assignees

中国科学院上海技术物理研究所

Dates

Publication Date: 20260512
Application Date: 20260330

Claims (10)

1. The low-stress mounting structure of the optical window is characterized by comprising a window inner frame (2), a window ring (3), a transition frame (4) and a window outer frame (5), wherein the window inner frame (2), the window ring (3) and the window outer frame (5) are arranged at the edge of the optical window (1) and are matched with the optical window (1) in shape, and openings of the optical window (1) are formed in the window inner frame (2) and the window ring (3); The window inner frame (2) comprises a vertical frame wall (21) and a mounting table (22) protruding inwards from the bottom of the frame wall (21), wherein the cross section of the window inner frame is L-shaped, the lower end edge of the optical window (1) is welded and fixed on the mounting table (22), a window ring (3) corresponds to the mounting table (22), the window ring (3) is welded and fixed at the upper end of the frame wall (21) of the window inner frame (2) and welded and fixed with the upper end edge of the optical window (1), and the window ring (3) and the mounting table (22) clamp and fix the optical window (1); The transition frame (4) is arranged between the window inner frame (2) and the window outer frame (5), the inner side of the transition frame (4) is welded and fixed with the window inner frame (2), a gap is reserved between the inner side of the transition frame (4) and the window inner frame (2), the outer side of the transition frame (4) is welded and fixed with the window outer frame (5), and a gap is reserved between the outer side of the transition frame (4) and the window outer frame (5).
2. The low stress mounting structure according to claim 1, wherein the transition frame (4) comprises a ring wall (41), an upper edge (42) and a lower edge (43) which are connected with each other, the upper edge (42) is arranged at the top of the ring wall (41) and protrudes inwards of the ring wall (41), the upper edge is welded and fixed with the upper end of the frame wall (21) of the window inner frame (2), a gap is reserved between the frame wall (21) and the ring wall (41), the lower edge (43) is arranged at the bottom of the ring wall (41) and protrudes outwards of the ring wall (41), the lower edge is welded and fixed with the inner bottom of the window outer frame (5), and a gap is reserved between the ring wall (41) and the window outer frame (5).
3. The low stress mounting structure according to claim 2, wherein the wall thickness of the annular wall (41) of the transition frame is 0.1mm to 0.2mm.
4. A low stress mounting structure according to claim 2, characterised in that the width of the gap between the frame wall (21) and the surrounding wall (41) of the window inner frame (2) is 0.5mm to 1mm.
5. The low stress mounting structure according to claim 1, wherein the material of the inner frame (2) of the window is matched to the coefficient of expansion of the material of the optical window (1).
6. A low stress mounting structure according to claim 1, characterised in that the material of the window ring (3) is identical to the material of the window inner frame (2).
7. The low stress mounting structure according to claim 6, wherein the thickness and the opening size of the window ring (3) are identical to those of the mounting table (22).
8. The low-stress mounting structure according to claim 1, wherein the material of the transition frame (4) is the same as the material of the window inner frame (2), or the material of the transition frame (4) is a material having good weldability with the window inner frame (2).
9. The low-stress mounting structure according to claim 1, wherein the material of the window frame (5) is a titanium alloy or an aluminum alloy.
10. The low-stress mounting arrangement as claimed in claim 1, characterized in that the edge of the optical window (1) is provided with a surface metallization layer with the welded area of the window ring (3) and the mounting table (22).

Description

Low-stress mounting structure of optical window Technical Field The invention relates to the technical field of infrared detector vacuum packaging, in particular to a low-stress mounting structure of an optical window. Background The infrared camera is a core component of an infrared remote sensing instrument, and the infrared detector assembly preparation technology has important significance in the field of aerospace and aviation infrared remote sensing. In the development of large-scale infrared detector components, the surface quality of an infrared optical window after airtight welding is an important factor influencing the infrared imaging result. With the development of the infrared detector scale, the focal plane size of the infrared detector is continuously increased, and the optical caliber of the infrared component is correspondingly increased, so that the difficulty is brought to the quality control of the surface shape after the welding of the optical window. The conventional optical window generally adopts a metal frame structure, namely, the optical window is embedded in the metal frame, and then airtight welding is performed in a mode of eutectic welding or soft metal welding and the like. On the one hand, because the expansion coefficients of the optical window material and the metal frame material cannot be perfectly matched, in the airtight welding of the optical window, the welding residual stress of the frame structure and the optical window can bring a certain influence to the window, and the degree of deterioration of the surface shape of the window is increased along with the increase of the caliber of the window. On the other hand, in order to consider the matching with the expansion coefficient of the window material, the window frame cannot be made of a lightweight material in the development of the component, and the lightweight design of the infrared detector component is affected. Considering that the infrared detector for space application has higher requirements on optical imaging quality, the optical indexes of all optical elements involved in the optical path of the infrared camera have more stringent requirements. The infrared detector assembly needs a low-stress optical window airtight welding structure and an implementation method, which can reduce residual stress after window welding and ensure the surface shape quality of the optical window of the infrared detector assembly while meeting the requirement of the airtight packaging of the infrared optical window. Meanwhile, the composite application of different materials on the optical window structure is realized through the stress isolation structure in the window structure, and the light weight design of the infrared detector assembly is realized. Disclosure of Invention The invention aims to provide a low-stress mounting structure of an optical window, which solves the problems that in the prior art, on one hand, the expansion coefficients of an optical window material and a metal frame material cannot be perfectly matched, the welding residual stress of the frame structure and the optical window can bring a certain influence to the optical window, the surface shape deterioration degree of the window is increased along with the increase of the caliber of the window, and on the other hand, in order to consider the matching property with the expansion coefficient of the window material, the window frame cannot be made of a lightweight material in the development of an assembly, so that the lightweight of an infrared detector assembly is difficult to realize. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: The low-stress mounting structure of the optical window comprises a window inner frame, a window ring, a transition frame and a window outer frame, wherein the window inner frame, the window ring, the transition frame and the window outer frame are arranged at the edge of the optical window and are matched with the optical window in shape; the window inner frame comprises a vertical frame wall and an inward mounting table at the bottom of the frame wall, wherein the cross section of the window inner frame is L-shaped, and the lower end edge of the optical window is welded and fixed on the mounting table; The transition frame is arranged between the window inner frame and the window outer frame, the inner side of the transition frame is fixedly welded with the window inner frame, a gap is reserved between the inner side of the transition frame and the window inner frame, the outer side of the transition frame is fixedly welded with the window outer frame, and a gap is reserved between the outer side of the transition frame and the window outer frame. The transition frame comprises a ring wall, an upper edge and a lower edge which are connected with each other, wherein the upper edge is arranged at the top of the ring wall and protrudes towards the inner side of the ri