Two-reflecting-surface integrated reflector and coaxial four-mirror optical system using the reflector

Abstract

The present invention relates to a two-reflection-surface integrated reflector and a coaxial four-mirror optical system using the reflector. The two reflective surfaces of the reflector are located on both sides of a common reflector and are coaxially arranged. A light-through hole is opened in the center of the common reflector. In the coaxial four-mirror optical system, the two reflective surfaces of the two-reflection-surface integrated reflector serve as the first reflector surface and the fourth reflector surface of the optical system respectively; the incident light is first reflected by the first reflector surface to the second reflector, and the light reflected by the second reflector is incident on the third reflector through the light-through hole of the two-reflection-surface integrated reflector. The light reflected by the third reflector is reflected by the fourth reflector surface and forms an image on the imaging focal plane. The present invention adopts a two-reflection-surface integrated processing design, which reduces the difficulty of processing and adjustment, has a high degree of reference overlap, and can effectively compress the axial length of the optical system, thereby improving reliability and environmental adaptability.

Description

Technical Field

[0001] The present invention relates to the field of optical precision instruments, and in particular to a two-reflection-surface integrated reflector and a coaxial four-mirror optical system using the reflector. Background Art

[0002] Micro-optical remote sensors are currently a key development direction for remote sensing payloads in the aerospace industry, characterized by their small size and light weight. Reflective optical systems have been widely used in space remote sensing systems due to their advantages such as achromatic aberration, small size, and lightweight.

[0003] The existing coaxial three-mirror optical system has a large central obstruction under large field of view conditions, which has a great impact on the energy entering the system and reduces the system transfer function and imaging quality. The off-axis three-mirror optical system is relatively difficult to process, assemble and optically inspect, and the three-mirror optical system has limited ability to correct distortion. The four-mirror optical system can make up for this technical deficiency. The invention patent with authorization announcement number CN102866487B and name "Coaxial Four-Mirror Ultra-Low Distortion Optical System" proposes a coaxial four-mirror ultra-low distortion optical system. On the basis of the coaxial TMA optical system, four mirrors with small optical power and large aspheric coefficients are introduced. The four mirrors are located near the system exit pupil. The system pupil aberration is corrected by the aspheric coefficients of the four mirrors, so that the system achieves ultra-low distortion. However, the total length of the system is large, the three and four mirrors are too far away from the main mirror, the structure is complex and large, the main mirror and the four mirrors are far apart, and the main mirror and the four mirrors cannot adopt an integrated structure. The invention patent with authorization publication number CN111367066B, entitled "A Coaxial Four-Mirror Optical System," proposes an optical structure using four coaxial mirrors. This utilizes multiple folds of the optical path to reduce the total length of the system, further reducing the barrel-to-focal length ratio of the optical system and improving the aberration balance capability of the optical system. Although the first and third reflectors in this system use a co-body design, the two reflective surfaces are located on the same side of the mirror body, resulting in low mirror body utilization. The invention patent with authorization publication number CN111812829B, entitled "A Main Three-Mirror Integrated Coaxial Four-Mirror Optical System," uses four secondary aspheric reflectors to facilitate correction of astigmatism and field curvature, and suppresses system stray light at the first image plane based on the principle of secondary imaging. The co-body reflectors in this system also have two reflective surfaces located on the same side of the mirror body, resulting in low mirror body utilization. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a two-reflection-surface integrated reflector with high mirror body utilization rate.

[0005] In order to solve the above technical problems, the two-reflection-surface integrated reflector of the present invention is characterized in that the two reflective surfaces are located on both sides of the common reflector and are coaxially arranged, and a light hole is opened in the center of the common reflector.

[0006] Furthermore, the co-body reflector is mounted on the back plate via a three-point flexible support structure on the back.

[0007] Furthermore, one side of the common reflector has three mounting holes evenly distributed at 120 degrees in the circumferential direction, and a cone sleeve is bonded and fixed in each mounting hole; the cone sleeve is connected to the back plate through a flexible support structure.

[0008] Preferably, the bonding surface between the tapered sleeve and the mounting hole is a tapered cylindrical surface.

[0009] Preferably, the flexible support structure has an integrated left flange, a right flange and three flexible support sections evenly distributed at 120° in the middle circumference; the flexible support structure is fixedly connected to the cone sleeve through the left flange and to the back plate through the right flange; each flexible support section has a flexible stress unloading groove.

[0010] Preferably, the flexible stress unloading groove is provided with 4 transverse grooves and 2 longitudinal grooves.

[0011] Preferably, lightweight holes are provided in the middle of the left flange and the right flange.

[0012] Preferably, the back plate has a lightweight hole structure.

[0013] The back plate is provided with three circumferentially distributed platform mounting interfaces for connection with the platform.

[0014] The present invention also requests protection for a coaxial four-mirror optical system using the above-mentioned two-reflection-surface integrated reflector, the system also including a second reflector and a third reflector; the two reflective surfaces of the two-reflection-surface integrated reflector respectively serve as the first reflective mirror surface and the fourth reflective mirror surface of the optical system; the incident light is first reflected by the first reflective mirror surface to the second reflector, the light reflected by the second reflector passes through the light hole of the two-reflection-surface integrated reflector and enters the third reflector, and the light reflected by the third reflector is reflected by the fourth reflective mirror surface and then imaged on the imaging focal plane.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] (1) The integrated processing design of the two reflective surfaces of the two-reflective-surface integrated reflector assembly of the present invention reduces the difficulty of processing and adjustment, has a high degree of reference coincidence, and effectively compresses the axial length of the optical system, making the structure compact.

[0017] (2) The two-reflecting-surface integrated reflector assembly of the present invention adopts a three-point support form on the back and is designed with an effective flexible support structure. On the one hand, it ensures the surface accuracy of the reflector under gravity conditions, and on the other hand, it can improve the impact of unevenness on the installation surface and changes in ambient temperature on the mirror surface. Under the same support effect, the weight of the assembly is significantly reduced, and the structure is simple, the support is stable, and the assembly accuracy is high, which meets the thermal stability and rigidity requirements of the reflector and ensures that the remote sensor has good imaging quality.

[0018] (3) The use of a two-reflection-surface integrated reflector structure in the coaxial four-mirror optical system can reduce the number of optical and mechanical structure connectors and improve reliability, thereby solving the problems of the coaxial four-mirror optical system being complex and bulky and having poor environmental adaptability. At the same time, the reflector assembly has a compact structure, strong environmental adaptability, and is easy to process and assemble.

[0019] The above-mentioned two-reflecting-surface integrated reflector adopts a three-point support form on the back, and a complete and effective flexible structure is designed on the flexible support structure. On the one hand, it ensures the surface accuracy of the reflector under gravity conditions, and on the other hand, it can improve the impact of unevenness of the installation surface and changes in ambient temperature on the mirror surface. Under the same support effect, the weight of the component is significantly reduced, and the structure is simple, the support is stable, and the assembly accuracy is high.

[0020] As the main component connecting the back plate and the reflector body, the flexible support structure has good dynamic and static mechanical properties and thermal properties, which can ensure that the reflector has a sufficiently good surface shape when the environmental conditions change.

[0021] As a core component of a remote sensing payload system, the installation, assembly, and positioning accuracy of the reflector directly impacts its surface shape, and thus the imaging quality of the remote sensing payload. The dual-reflecting-surface integrated reflector of the present invention can be used in a coaxial four-mirror optical system, reducing the number of optical and mechanical components required, improving reliability, and making the system compact, environmentally adaptable, and easy to manufacture and assemble. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A cutaway perspective view of a two-reflection-surface integrated reflector according to the present invention;

[0023] Figure 2 A three-dimensional diagram of a two-reflection-surface integrated reflector according to the present invention;

[0024] Figure 3 This is an exploded view of the two-reflection-surface integrated reflector of the present invention;

[0025] Figure 4a 、 4b It is a stereoscopic image of a reflector with two integrated reflective surfaces;

[0026] Figure 55a and 5b are the cutaway and overall stereograms of the cone sleeve, respectively;

[0027] Figure 6a 、 6b is a three-dimensional diagram of the flexible support structure;

[0028] Figure 7a 、 7b It is a three-dimensional diagram of the back panel structure;

[0029] Figure 8 Schematic diagram of the coaxial four-mirror optical system of the present invention.

[0030] Description of reference numerals:

[0031] 1. Common reflector; 11. Light aperture; 2. Cone sleeve; 3. Flexible support structure; 4. Back plate; 5. Screws; 21. Connection surface between cone sleeve and flexible support structure; 21. Bottom inner surface; 22. Sidewall outer surface; 31. Left flange; 32. Right flange; 33. Flexible support joint; 331. Flexible stress relief groove; 41. Back plate and platform mounting interface; 42. Back plate and flexible support structure mounting surface.

[0032] 61. Second reflecting mirror; 62. Two-reflecting-surface integrated reflecting mirror; 621. First reflecting mirror surface; 622. Fourth reflecting mirror surface; 63. Third reflecting mirror; 64. Imaging focal plane. DETAILED DESCRIPTION

[0033] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, rather than all structures.

[0034] In the description of the present invention, unless otherwise expressly specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0035] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," or "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," or "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0036] In the description of this embodiment, terms such as "upper," "lower," "left," and "right" are used to refer to positions or locations based on those shown in the accompanying drawings. These terms are intended solely to facilitate description and simplify operation, and are not intended to indicate or imply that the devices or components referred to must be oriented, constructed, or operated in a specific manner. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used solely for descriptive purposes and have no special meaning.

[0037] like Figure 1-3 As shown, the two-reflecting-surface integrated reflector of the present invention comprises a co-body reflector 1 and a back plate 4 ; the co-body reflector 1 is mounted on the back plate 4 via a three-point flexible support structure 3 on the back.

[0038] As shown in Figure 4, the co-body reflector 1 has two reflective surfaces, which are designed and processed in an integrated manner and are coaxially arranged. The two reflective surfaces are located on both sides of the co-body reflector, and a light hole 11 is opened in the center of the co-body reflector. The back plate 4 has a lightweight hole structure.

[0039] One side of the common reflector 1 has three mounting holes evenly distributed at 120° in the circumferential direction, and a cone sleeve 2 is fixed in each mounting hole by adhesive.

[0040] Preferably, the cone sleeve 2 is in the shape of a cylinder with one side open, and the outer surface 22 of the side wall is a conical cylindrical surface, which serves as the bonding surface between the cone sleeve and the mounting hole.

[0041] The bottom inner surface 21 of the cone sleeve 2 is the connection surface between the cone sleeve and the flexible support structure 3 , and a threaded hole is provided at the bottom of the cone sleeve.

[0042] Taking the flexible support structure at one point on the back as an example, the flexible support structure has an integrated left flange 31, a right flange 32, and three flexible support sections 33 evenly distributed at 120° around the middle. Lightweight holes are set in the middle of the left flange 31 and the right flange 32. Each flexible support section 33 has a flexible stress unloading groove 331, which has four transverse grooves and two longitudinal grooves. The groove width is determined by the flexibility of the flexible support structure. This flexible support structure can effectively unload other stresses and strains from the axial, circumferential and radial directions, as well as from the two rotational directions, reducing the deformation of the mirror due to changes in the external environment (such as gravity release, thermal radiation, temperature changes, assembly errors, etc.), effectively ensuring that the mirror meets the ultra-high surface shape requirements.

[0043] The flexible support structure 3 is fixedly connected to the cone sleeve 2 through the left flange 31 and screws, and is fixedly connected to the back plate 4 through the right flange 32 and screws.

[0044] The back plate 4 is designed with three circumferentially distributed back plate and platform mounting interfaces 41 and a back plate and flexible support structure mounting surface 42 .

[0045] The above-mentioned two-reflecting-surface integrated reflector adopts a three-point support form on the back, and a complete and effective flexible structure is designed on the flexible support structure. On the one hand, it ensures the surface accuracy of the reflector under gravity conditions, and on the other hand, it can improve the impact of unevenness of the installation surface and changes in ambient temperature on the mirror surface. Under the same support effect, the weight of the component is significantly reduced, and the structure is simple, the support is stable, and the assembly accuracy is high.

[0046] As the main component connecting the back plate and the reflector body, the flexible support structure has good dynamic and static mechanical properties and thermal properties, which can ensure that the reflector has a sufficiently good surface shape when the environmental conditions change.

[0047] As a core component of a remote sensing payload system, the installation, assembly, and positioning accuracy of the reflector directly impacts its surface shape, and thus the imaging quality of the remote sensing payload. The dual-reflecting-surface integrated reflector of the present invention can be used in a coaxial four-mirror optical system, reducing the number of optical and mechanical components required, improving reliability, and making the system compact, environmentally adaptable, and easy to manufacture and assemble.

[0048] like Figure 8As shown, the coaxial four-mirror optical system using the above-mentioned two-reflection-surface integrated reflector also includes a second reflector 61 and a third reflector 63; the two reflective surfaces of the two-reflection-surface integrated reflector 62 serve as the first reflective mirror surface 621 and the fourth reflective mirror surface 622 of the optical system respectively; the incident light is first reflected by the first reflective mirror surface 621 to the second reflector 61, and the light reflected by the second reflector 61 is incident on the third reflector 63 through the light hole 44 of the two-reflection-surface integrated reflector, and the light reflected by the third reflector 63 is reflected by the fourth reflective mirror surface 622 to form an image on the imaging focal plane 64.

[0049] The above specific embodiments are further explanations of the technical solutions provided by the present invention, but should not be understood as limitations of the present invention.

Claims

1. A two-reflecting-surface integrated reflector, characterized in that Two reflecting surfaces are located on both sides of a co-body reflector and are coaxially arranged. A light hole (11) is opened in the center of the co-body reflector. One side of the co-body reflector (1) has three mounting holes uniformly distributed at 120 degrees in a circumferential direction, and a cone sleeve (2) is bonded and fixed in each mounting hole. The cone sleeve (2) is connected to the back plate (4) through a flexible support structure (3). The flexible support structure has an integrated left flange (31), a right flange (32) and three flexible support sections (33) uniformly distributed at 120 degrees in the middle circumferential direction. The flexible support structure (3) is fixedly connected to the cone sleeve (2) through the left flange (31) and fixedly connected to the back plate (4) through the right flange (32). Each flexible support section (33) has a flexible stress unloading groove (331), and the flexible stress unloading groove (331) is provided with four transverse grooves and two longitudinal grooves.

2. The two-reflecting-surface integrated reflector according to claim 1, characterized in that The bonding surface between the tapered sleeve (2) and the mounting hole is a tapered cylindrical surface.

3. The two-reflection-surface integrated reflector according to claim 1, characterized in that Lightweight holes are provided in the middle of the left flange (31) and the right flange (32).

4. The two-reflecting-surface integrated reflector according to claim 1, characterized in that The back plate (4) has a lightweight hole structure.

5. The two-reflection-surface integrated reflector according to claim 1, characterized in that The back plate (4) is provided with three circumferentially distributed platform mounting interfaces (41) for connection with the platform.

6. A coaxial four-mirror optical system using the reflective surface integrated reflector according to claim 1, characterized in that The system further comprises a second reflector (61) and a third reflector (63); the two reflective surfaces of the two-reflective-surface integrated reflector (62) respectively serve as the first reflective mirror surface (621) and the fourth reflective mirror surface (622) of the optical system; the incident light is first reflected by the first reflective mirror surface (621) to the second reflector (61); the light reflected by the second reflector (61) is incident on the third reflector (63) through the light hole (44) of the two-reflective-surface integrated reflector; the light reflected by the third reflector (63) is reflected by the fourth reflective mirror surface (622) and forms an image on the imaging focal plane (64).

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