Off-axis three-mirror optical pod

Abstract

The application discloses an off-axis three-mirror optical pod, which comprises a frame body, a primary mirror assembly, a secondary mirror assembly, a tertiary mirror assembly, a folding mirror assembly and a cutting mirror assembly which are installed on the frame body, and the frame body, the primary mirror assembly, the secondary mirror assembly, the tertiary mirror assembly, the folding mirror assembly and the cutting mirror assembly are all made of a silicon-aluminum alloy material to form a full silicon-aluminum system. The off-axis three-mirror optical pod is designed to be integrated and athermalized, and high rigidity, high stability, light weight and excellent thermal compatibility are achieved. When the environmental temperature changes, the whole pod structure uniformly expands or shrinks, the thermal stress and structural deformation caused by thermal mismatch of materials are effectively avoided, the image surface stability and imaging quality of the optical system are ensured, and the optical pod can be well applied to flight platforms such as airplanes and unmanned aerial vehicles.

Description

Technical Field

[0001] This invention relates to the field of airborne optoelectronic detection technology, specifically to an off-axis three-mirror optical pod. Background Technology

[0002] Off-axis three-mirror optical systems are widely used in high-performance aerospace optoelectronic pods due to their advantages such as unobstructed views, large field of view, and high image quality. However, these systems have complex structures, and the relative positions and surface accuracy between the mirrors are required to be extremely high, typically at the micrometer level. Furthermore, aerospace pods are subjected to drastic temperature changes, aerodynamic loads, vibrations, and shocks during operation. These environmental factors can easily cause deformation and displacement of optical components, leading to image quality degradation or even system failure.

[0003] Traditional off-axis three-mirror structures often use different materials such as beryllium, microcrystalline glass, and silicon carbide to manufacture mirrors and structural components in pursuit of high rigidity and low thermal expansion. However, this brings the following problems: 1) The thermal expansion coefficients of different materials are mismatched, generating thermal stress when the temperature changes, leading to mirror surface deformation and structural instability; 2) The diversity of materials increases the complexity and cost of manufacturing, assembly, and maintenance; 3) Some high-performance materials (such as beryllium) are expensive and toxic, and difficult to process.

[0004] Therefore, there is an urgent need for an off-axis three-mirror optical pod structure that can guarantee high precision and stability, as well as good environmental adaptability, lightweight and low cost. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an off-axis three-mirror optical pod that is compact, lightweight, low-cost and has high thermal compatibility, in order to overcome the shortcomings of the existing technology.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: An off-axis three-mirror optical pod includes a frame body and a primary mirror assembly, a secondary mirror assembly, a third mirror assembly, a folding mirror assembly, and a cutting mirror assembly mounted on the frame body. The frame body, the primary mirror assembly, the secondary mirror assembly, the third mirror assembly, the folding mirror assembly, and the cutting mirror assembly are all made of silicon-aluminum alloy to form an all-silicon-aluminum system.

[0007] As a further improvement of the present invention, the main mirror assembly, the three-mirror assembly and the folding mirror assembly are all connected to the frame body through flexible support members.

[0008] As a further improvement of the present invention, the primary mirror assembly, secondary mirror assembly, third mirror assembly, folding mirror assembly and cutting mirror assembly all include a reflector, and the optical reflecting surface and the mechanical mounting reference surface of the reflector are obtained by ultra-precision single-point diamond turning in an integrated process.

[0009] As a further improvement of the present invention, the flexible support is provided with a plurality of I-shaped connecting slots, which are used to connect the reflector and the frame body; the connecting slots are flexible in the radial direction of the optical axis and rigid in the axial direction of the optical axis.

[0010] As a further improvement of the present invention, the frame body integrates a primary mirror mounting position, a secondary mirror mounting position, a third mirror mounting position, a folding mirror mounting position, and a cutting mirror mounting position.

[0011] Compared with the prior art, the off-axis three-mirror optical pod of the present invention has the following advantages: (1) Thermalless design: Since the entire frame body and all mirror components of the off-axis three-mirror optical pod are made of the same silicon-aluminum alloy material, the entire pod structure expands or contracts uniformly when the ambient temperature changes, effectively avoiding thermal stress and structural deformation caused by material thermal mismatch, and ensuring the image plane stability and imaging quality of the optical system.

[0012] (2) High precision and high stability: The integrated frame body minimizes assembly errors and provides extremely high rigidity and positional stability. Combined with the flexible support provided by the flexible support component, it can not only accurately fix the reflector, but also effectively release internal stress, ensuring the long-term stability of the reflector surface accuracy and relative position.

[0013] (3) Lightweight: Through the application of silicon-aluminum alloy materials, a high stiffness-to-weight ratio of the structure is achieved, which is particularly suitable for weight-sensitive aerospace applications.

[0014] (4) Processability and low cost: The all-silicon aluminum structure is easy to machine and ultra-precision turn, which simplifies the manufacturing and assembly process and reduces manufacturing costs and cycle time. Attached Figure Description

[0015] Figure 1 This is a schematic diagram illustrating the structural principle of the off-axis three-mirror optical pod in a specific embodiment of the present invention; Figure 2 This is a schematic diagram of the structural principle of the frame body in a specific embodiment of the present invention; Figure 3 This is a schematic diagram illustrating the assembly structure principle of the flexible support and the three-mirror assembly in a specific embodiment of the present invention.

[0016] Legend: 1. Frame body; 2. Primary lens assembly; 3. Secondary lens assembly; 4. Tertiary lens assembly; 5. Folding lens assembly; 6. Flexible support component; 7. Cutting lens assembly; 101. Primary lens mounting position; 102. Secondary lens mounting position; 103. Tertiary lens mounting position; 104. Folding lens mounting position; 105. Cutting lens mounting position; 601. Connecting slot. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but this does not limit the scope of protection of the present invention.

[0018] In the description of this invention, it should be understood that the terms "side", "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0019] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more unless otherwise explicitly specified.

[0020] Example like Figure 1 , Figure 2 and Figure 3 As shown, the off-axis three-mirror optical pod of the present invention includes a frame body 1, and a primary mirror assembly 2, a secondary mirror assembly 3, a three-mirror assembly 4, a folding mirror assembly 5, and a cutting mirror assembly 7 mounted on the frame body 1. The frame body 1, the primary mirror assembly 2, the secondary mirror assembly 3, the three-mirror assembly 4, the folding mirror assembly 5, and the cutting mirror assembly 7 are all made of silicon-aluminum alloy to form an all-silicon-aluminum system.

[0021] like Figure 2 As shown, in this embodiment, the frame body 1 is the core load-bearing component of the entire system. It is a lens barrel assembly structure formed by separate rough machining of the main lens barrel and the lens barrel base, followed by five-axis CNC milling for integrated precision machining, thus meeting the requirements of lightweight and high rigidity. The frame body 1 is precision machined to form the main lens mounting position 101, the secondary lens mounting position 102, the tertiary lens mounting position 103, the folding lens mounting position 104, and the cutting lens mounting position 105. It is understood that the relative positions between each mounting position are guaranteed by the lens barrel assembly structure itself, and the relative angles and distances between each mounting position are completed in a single clamping operation during machining to ensure extremely high initial positional accuracy.

[0022] In this embodiment, the primary mirror assembly 2, secondary mirror assembly 3, tertiary mirror assembly 4, folding mirror assembly 5, and cutting mirror assembly 7 all include reflectors, and the optical reflecting surface and mechanical mounting reference surface of the reflectors are obtained by ultra-precision single-point diamond turning in an integrated process.

[0023] In this embodiment, the main mirror assembly 2, the three-mirror assembly 4, and the folding mirror assembly 5 have similar structures and are all connected to the frame body 1 via flexible support members 6. Taking the three-mirror assembly 4 as an example, its flexible joint is integrally processed with the reflector body. The reflector itself is made of silicon-aluminum alloy, and its aspherical surface of optical reflection is machined by ultra-precision single-point diamond turning. Simultaneously, a mechanical positioning reference surface is also machined on its back, ensuring extremely high coaxiality and perpendicularity between the optical surface and the mechanical reference. It is then shaped by magnetorheological processing. The flexible support member 6 uses three evenly distributed I-shaped connecting slots 601 to connect the reflector and the mirror tube, such as... Figure 3 As shown. Each I-shaped connecting slot 601 is flexible in the radial direction of the optical axis to compensate for dimensional changes caused by temperature and assembly variations, while it is rigid in the axial direction perpendicular to the optical axis to ensure the positioning of the reflector. The primary mirror assembly 2 and the folding mirror assembly 5 are mounted to the corresponding primary mirror mounting positions 101 and folding mirror mounting positions 104 on the frame body 1 in a similar manner.

[0024] In this embodiment, through a systematic design of "all-silicon-aluminum material + integrated processing structure + flexible support," all structural components and mirrors in the pod are made of silicon-aluminum alloy, forming an all-aluminum material system. The frame body 1 is an integrated, machined mirror barrel structure, with precision machining ensuring the initial accuracy of each lens mounting position. Each mirror assembly is connected to the frame body 1 via a flexible support 6. The flexible support 6 provides rigid positioning along the optical axis and flexibility in the radial direction of the optical axis to release stress, effectively solving the problem of image quality degradation caused by temperature changes and vibrations in traditional off-axis three-mirror systems under airborne conditions. It combines advantages such as high precision, high stability, lightweight, and low cost, making it suitable for use on aircraft, drones, and other flight platforms.

[0025] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. An off-axis three-mirror optical pod, characterized in that, The system includes a frame body (1), and a primary mirror assembly (2), a secondary mirror assembly (3), a tertiary mirror assembly (4), a folding mirror assembly (5), and a cutting mirror assembly (7) mounted on the frame body (1). The frame body (1), the primary mirror assembly (2), the secondary mirror assembly (3), the tertiary mirror assembly (4), the folding mirror assembly (5), and the cutting mirror assembly (7) are all made of silicon-aluminum alloy to form an all-silicon-aluminum system.

2. The off-axis three-mirror optical pod according to claim 1, characterized in that, The main mirror assembly (2), the three-mirror assembly (4) and the folding mirror assembly (5) are all connected to the frame body (1) through a flexible support member (6).

3. The off-axis three-mirror optical pod according to claim 2, characterized in that, The primary mirror assembly (2), secondary mirror assembly (3), tertiary mirror assembly (4), folding mirror assembly (5), and cutting mirror assembly (7) all include reflectors, and the optical reflecting surface and mechanical mounting reference surface of the reflectors are obtained by ultra-precision single-point diamond turning integrated machining.

4. The off-axis three-mirror optical pod according to claim 3, characterized in that, The flexible support (6) is provided with multiple I-shaped connecting slots (601), which are used to connect the reflector and the frame body (1). The connecting slots (601) are flexible in the radial direction of the optical axis and rigid in the axial direction of the optical axis.

5. The off-axis three-mirror optical pod according to any one of claims 1 to 4, characterized in that, The frame body (1) integrates a primary mirror mounting position (101), a secondary mirror mounting position (102), a tertiary mirror mounting position (103), a folding mirror mounting position (104), and a cutting mirror mounting position (105).

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