An adaptive lens for coaxial reflective optical system

Abstract

The present invention relates to an adaptive lens applied to a coaxial reflective optical system, comprising a primary mirror, a secondary mirror, a secondary mirror support rod and a primary mirror support structure made of SIC material, the primary mirror support structure being provided with a prism, and also comprising a secondary mirror support seat connected to the primary mirror support structure via a split secondary mirror support rod, the secondary mirror support seat being made of a carbon fiber composite material whose linear expansion coefficient matches that of the SIC material. The present invention has better thermal stability, completely solves the thermal sensitivity problem of the reflective lens, and achieves a non-thermal design of the lens; and has no weak links, and the overall mechanical stability is very high, and its unit density is only 3.5g / mm 3 The TC4 or 4J32 flexible transition link in the traditional reflective lens is eliminated, and the benchmark of the entire system is unified, which reduces the cumulative error, increases the allowable error of a single piece, reduces the complexity of installation and adjustment, and improves the installation and adjustment efficiency, which is equivalent to reducing production time and reducing production costs.

Description

Technical Field

[0001] The invention belongs to the technical field of space cameras, and in particular relates to an adaptive lens applied to a coaxial reflective optical system. Background Art

[0002] At present, due to the limitations of the manufacturing process of large-aperture lenses, the long-focal-length and large-aperture optical systems in aerospace and ground tracking and mapping equipment all use reflective optical systems. However, the front reflective optical path in the reflective optical system, that is, the reflective optical lens, has the disadvantages of being sensitive to thermal influence, requiring high mechanical conditions, complex assembly and adjustment, and requiring high assembly and adjustment accuracy. This also determines the high price of the reflective optical lens. The high assembly and adjustment accuracy and complex assembly and adjustment process also make the reflective optical lens processing cycle very long. The above problems are the main reasons that restrict the real widespread application of reflective optical cameras.

[0003] The existing conventional solution is to use the linear expansion coefficient of different materials to improve the thermal stability of the entire lens. Specifically, the SIC lightweight primary and secondary mirrors are embedded with 4J32 structural parts with adjusted linear expansion coefficients, connected to the TC4 backplane, carbon fiber composite backplane or aluminum-based composite backplane through a flexible transition structure, and then the carbon fiber composite support rod or bracket is connected to the backplane, and the front end of the support rod is connected to the secondary mirror backplane. The secondary mirror is then embedded with 4J32 structural parts, and then connected to the secondary mirror backplane through a flexible transition structure, thus forming a front reflective lens of a coaxial reflective optical camera.

[0004] The above scheme needs to constantly match the linear expansion coefficients of different materials to improve the thermal stability of the entire lens, but this is quite difficult to achieve in terms of process. The composite material support rod changes the linear expansion coefficient through the layer structure and the thickness of the glue layer. Since the distance between the primary and secondary mirrors of the large-aperture and long-focal-length coaxial reflection system is relatively far, if there is a slight problem in matching the linear expansion coefficient, then a slight error will lead to a huge difference. In order to improve thermal stability, flexible transition structures are provided behind the primary mirror and the secondary mirror. However, based on the harsh vibration conditions of the active section of the rocket launch, the flexible structure must not only consider the temperature transition, but also the relationship between its weak points and the mechanical instability caused by the entire system. At the same time, the introduction of the flexible structure complicates the benchmark during the installation and adjustment process. The benchmark needs to be repaired step by step during the installation and adjustment so that its cumulative error does not exceed the optical requirements, which also makes it impossible to reasonably control the production cycle and production costs. Summary of the invention

[0005] The purpose of the present invention is to provide an adaptive lens with good thermal and mechanical adaptability for use in a coaxial reflective optical system, so as to overcome the shortcomings of the current devices in this technical field, such as narrow thermal adaptability range, poor mechanical stability, complex installation and adjustment, and low installation and adjustment efficiency.

[0006] The objective of the present invention is achieved through the following technical solutions:

[0007] An adaptive lens applied to a coaxial reflective optical system comprises a primary mirror, a secondary mirror and a primary mirror support structure for supporting the primary mirror, characterized in that:

[0008] It also includes a secondary mirror support seat and a secondary mirror support rod, wherein the secondary mirror support seat is integrally formed with the secondary mirror, and the secondary mirror support seat is connected to the primary mirror support structure through the secondary mirror support rod; the secondary mirror support rod is formed by connecting upper and lower support rods, wherein the upper support rod is connected to the primary mirror, and the lower support rod is connected to the secondary mirror support seat;

[0009] The primary mirror support structure is provided with a prism;

[0010] The primary mirror, secondary mirror, secondary mirror support rod and primary mirror support structure are all made of SIC material and have the same linear expansion coefficient. The secondary mirror support seat is made of a carbon fiber composite material whose linear expansion coefficient matches that of the SIC material.

[0011] Furthermore, the main mirror and the main mirror supporting structure are formed in one piece.

[0012] Furthermore, the secondary mirror support seat is a triangular structure, a hole is opened in the center of its support plane, and the three corners of the support plane are glued to the secondary mirror support seat for connecting the secondary mirror.

[0013] Furthermore, the bottom of the secondary mirror is provided with an embedded seat integrally formed therewith, and the bottom of the embedded seat is provided with three embedded holes for snapping into the embedded secondary mirror support seat, and after the secondary mirror support seat is embedded and snapped into the embedded holes, it is fixed by fasteners.

[0014] Furthermore, a lower support rod for connecting to the lower support rod is glued and embedded on the side wall of the secondary mirror support seat.

[0015] Furthermore, the connecting end of the lower support rod and the secondary mirror support seat is sleeved on the embedded lower support rod and fixed by a fastener.

[0016] Furthermore, the connecting end of the upper support rod and the primary mirror support structure is glued to the secondary mirror support rod connection embedded, and an adjustment gasket is arranged between the secondary mirror support rod connection embedded and the primary mirror support structure for adjusting the interval between the primary and secondary mirrors.

[0017] Furthermore, the connection ends of the upper and lower support rods are glued to the secondary mirror support rods for embedding and fixed with fasteners.

[0018] Furthermore, the prism is glued in the mirror chamber, and the mirror chamber is connected to the screw holes pre-buried on the side of the main mirror support structure by screws.

[0019] Furthermore, the adjustment gasket, the embedded lower support rod, the embedded secondary mirror support seat, the embedded secondary mirror support rod and the embedded secondary mirror support rod connection are all made of 4J32 material whose linear expansion coefficient matches that of SIC material.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The adaptive lens of the present invention applied to the coaxial reflective optical system has better thermal stability, completely solves the thermal sensitivity problem of the reflective lens, and achieves a thermal design of the lens; and has no weak links, and the overall mechanical stability is very high, and its unit density is only 3.5g / mm 3 The TC4 or 4J32 flexible transition link in the traditional reflective lens is eliminated, and the benchmark of the entire system is unified, which reduces the cumulative error, increases the allowable error of a single piece, reduces the complexity of installation and adjustment, and improves the installation and adjustment efficiency, which is equivalent to reducing production time and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings described herein are used to provide further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0023] Figure 1 It is a schematic structural diagram of the athermalized lens of the present invention applied to a coaxial reflective optical system;

[0024] Figure 2 A schematic structural diagram of another angle of the athermalized lens of the present invention applied to a coaxial reflective optical system;

[0025] Figure 3 is a schematic diagram of the structure of the secondary mirror support rod;

[0026] Figure 4 is a schematic diagram of the structure of the secondary mirror support;

[0027] Figure 5 Schematic diagram of the structure of the secondary mirror. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0029] like Figure 1-Figure 2As shown, the present invention is applied to an adaptive lens of a coaxial reflective optical system, comprising a primary mirror 1, a secondary mirror 7 and a primary mirror support structure 16 for supporting the primary mirror 1, and also comprising a secondary mirror support seat 6 and a secondary mirror support rod for ensuring the primary and secondary intervals. The secondary mirror support seat 6 is connected to the primary mirror support structure 16 through the secondary mirror support rod. In the present invention, the secondary mirror support seat 6 is combined with the secondary mirror support rod to form a stable secondary mirror static support structure. The secondary mirror support rod is a split structure, which is connected by upper and lower support rods. Among them, the upper support rod 3 is connected to the primary mirror 1, thereby determining the overall reflector lens. The lower support rod 4 is connected to the secondary mirror support seat 6.

[0030] The primary mirror 1 and the primary mirror support structure 16 of the present invention are an integrated structure, and the secondary mirror 7 and the secondary mirror support seat 6 are also an integrated structure, which are all formed in one piece by SIC secondary sintering. The purpose of the integrated forming is to reduce the connection structure, simplify the system composition, reduce unnecessary flexible transition structures to reduce the introduced errors, reduce the difficulty of installation and adjustment, and improve the stability of the system. At the same time, the mirror and the support structure are made of the same material under the same process, so their linear expansion coefficients are completely matched, and the previously large embedded parts are changed into local embedded parts with very small volumes, so that the matching degree of the linear expansion coefficient is greatly improved, resulting in improved temperature adaptability.

[0031] The main mirror support structure 16 is equipped with a prism 9 for detection, and the processing benchmark is uniformly adjusted. The prism 9 can be installed in three directions (three positions) according to needs, specifically on the outer wall of any corner of the main mirror support structure 16. The prism 9 itself is glued in the mirror chamber, and the mirror chamber is connected to the screw holes embedded in the side of the main mirror support structure 16 by screws. Fixing the prism 9 on the main mirror support structure 16 has a stable structure, improves the detection accuracy, and improves the detection stability.

[0032] One embodiment of the present invention, as Figure 3 As shown, the upper and lower support rods are connected by the embedded secondary mirror support rod 8 to form a secondary mirror support rod as a whole, specifically: the connecting ends of the upper and lower support rods are glued to the embedded secondary mirror support rod 8, and fasteners, which can be screws or pins. The interval between the primary mirror 1 and the secondary mirror 7 is ensured by the connection between the upper support rod 3 and the lower support rod 4. Since the SIC material cannot punch screw holes, based on this, all connections of the present invention use embedded 4J32 material embedded parts, and the linear expansion coefficient matching accuracy is within the range of e-7. According to calculations, the influence on the entire primary and secondary mirror interval is very small. The rest of the primary mirror 1, secondary mirror 7, secondary mirror support rod and primary mirror support structure 16 are all SIC materials, and the linear expansion coefficient matching degree is very high. Therefore, the interval between the primary and secondary mirrors will not change due to temperature changes, so the thermal stability of the entire system is very high. The optical camera using this lens can be completely athermalized, and the imaging quality can be guaranteed without active thermal control.

[0033] In one embodiment of the present invention, the secondary mirror 7 is fixed above the secondary mirror support seat 6, such as Figure 4 As shown, the secondary mirror support seat 6 is a triangular structure, and the center of its support plane is opened to make the structure lightweight and reserve a process hole for secondary mirror inspection. The three corners of the support plane are glued to the secondary mirror support seat 14 for connecting the secondary mirror 7. Figure 5 As shown, the secondary mirror 7 includes a mirror surface 11 and an embedded seat 12 disposed below the mirror surface 11 and formed integrally therewith. The embedded seat 12 has three embedded holes 17 at the bottom thereof for engaging the embedded secondary mirror support seat 14. The shape of the embedded holes 17 matches the embedded secondary mirror support seat 14. After the embedded holes of the secondary mirror are tightly engaged with the embedded secondary mirror support seat, they are fixed by fasteners, which may be screws or pins, to achieve the fixation of the secondary mirror support seat 6 and the secondary mirror 7.

[0034] In one embodiment of the present invention, three side walls of the secondary mirror support seat 6 are glued with lower support rod pre-embedded 15 for connecting the lower support rod 4. The connecting end 10 of the lower support rod 4 and the secondary mirror support seat 6 is sleeved on the lower support rod pre-embedded 15 and fixed by a fastener, which can be a screw or a pin.

[0035] In one embodiment of the present invention, the connection end of the upper support rod 3 and the primary mirror support structure 16 is glued to the secondary mirror support rod connection embedded 13, and an adjustment gasket 2 is arranged between the secondary mirror support rod connection embedded 13 and the primary mirror support structure 16 to adjust the interval between the primary and secondary mirrors. In the present invention, the secondary mirror end and the secondary mirror support rod are connected to the primary mirror support structure 16 in an integral form through the only adjustment link adjustment gasket 2, and the interval between the primary and secondary mirrors is adjusted by adjusting the gasket 2 to eliminate system errors.

[0036] In one embodiment of the present invention, the secondary mirror support seat is further provided with a secondary mirror light shield connection port 5 for connecting the secondary mirror light shield.

[0037] In the present invention, except for the adjustment gasket 2, the lower support rod embedded 15, the secondary mirror support seat embedded 14, the secondary mirror support rod embedded 8, the secondary mirror support rod connection embedded 13 and the secondary mirror support seat 6, all are made of SIC material and have the same linear expansion coefficient. The adjustment gasket 2, the lower support rod embedded 15, the secondary mirror support seat embedded 14, the secondary mirror support rod embedded 8 and the secondary mirror support rod connection embedded 13 are all made of 4J32 material whose linear expansion coefficient matches that of the SIC material. The secondary mirror support seat 6 is made of a carbon fiber composite material whose linear expansion coefficient matches that of the SIC material, and utilizes the anisotropic characteristics of its material layering engineering molding, so that after molding, it has the characteristic that the normal (normal to the optical axis) modulus is higher than the axial modulus (optical axis direction), so that it has the ability to eliminate installation stress at the secondary mirror end. The installation stress of the entire system has an outlet and will not be transmitted to the mirror surface, so that the wavefront shape accuracy is disturbed.

[0038] Since the proportion of 4J32 material and carbon fiber composite material in the reflector lens of this invention is very small, the thermal sensitivity caused by the different linear expansion coefficients between different materials is very small, so the thermal stability is very high. The secondary mirror support seat 6 under the secondary mirror 7 is used as the flexible release unit of the entire structure, which can not only adapt to the stress introduced by the processing error during the connection, but also will not form local stress concentration.

[0039] In the present invention, the secondary mirror support rod is reconnected as a split type, and is not made into an integral body, which reduces the difficulty of the SIC material in the firing process and greatly improves the structure acquisition and the finished product rate.

[0040] The camera lens of the present invention basically has a full SIC structure and has high engineering feasibility, and the reflective lens of the same material is also the best way to achieve thermal stability. Since the SIC modulus is too high, if the mounting surface is slightly uneven, it will introduce a lot of internal stress. The present invention also overcomes the problems caused by the properties of the SIC material itself through innovation in the selection of the material of the secondary mirror support seat 6. At the same time, it also improves the mechanical stability of the system and eliminates weak points.

[0041] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0042] In addition, the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0043] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0044] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0045] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0046] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

[0047] The specific implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. An adaptive lens for a coaxial reflective optical system, comprising a primary mirror (1), a secondary mirror (7) and a primary mirror support structure (16) for supporting the primary mirror (1), characterized in that: It also comprises a secondary mirror support seat (6) and a secondary mirror support rod, wherein the secondary mirror support seat (6) and the secondary mirror (7) are integrally formed, and the secondary mirror support seat (6) is connected to the primary mirror support structure (16) via the secondary mirror support rod; the secondary mirror support rod is formed by connecting upper and lower support rods, wherein the upper support rod (3) is connected to the primary mirror (1), and the lower support rod (4) is connected to the secondary mirror support seat (6); The primary mirror support structure (16) is provided with a prism (9); The primary mirror (1), the secondary mirror (7), the secondary mirror support rod and the primary mirror support structure (16) are all made of SIC material and have the same linear expansion coefficient, and the secondary mirror support seat (6) is made of a carbon fiber composite material whose linear expansion coefficient matches that of the SIC material.

2. The adaptive lens for a coaxial reflective optical system according to claim 1, characterized in that: The main mirror (1) and the main mirror support structure (16) are integrally formed.

3. The adaptive lens for a coaxial reflective optical system according to claim 1, characterized in that: The secondary mirror support seat (6) is a triangular structure, the center of the support plane of which is opened, and the three corners of the support plane are glued to the secondary mirror support seat pre-embedded (14) for connecting the secondary mirror (7).

4. The adaptive lens for a coaxial reflective optical system according to claim 3, characterized in that: The secondary mirror (7) comprises a mirror surface (11) and an embedded seat (12) arranged below the mirror surface (11) and formed integrally therewith, and the embedded seat (12) has three embedded holes (17) at the bottom thereof for clamping the embedded secondary mirror support seat.

5. The adaptive lens for a coaxial reflective optical system according to claim 1, characterized in that: The side wall of the secondary mirror support seat (6) is glued with a lower support rod pre-embedded (15) for connecting to the lower support rod (4).

6. The adaptive lens for a coaxial reflective optical system according to claim 5, characterized in that: The connecting end (10) of the lower support rod (4) and the secondary mirror support seat (6) is sleeved on the lower support rod pre-embedded (15) and fixed by a fastener.

7. The adaptive lens for a coaxial reflective optical system according to claim 1, characterized in that: The connecting end of the upper support rod (3) and the primary mirror support structure (16) is glued to the secondary mirror support rod connection embedding (13), and an adjustment gasket (2) is also provided between the secondary mirror support rod connection embedding (13) and the primary mirror support structure (16) for adjusting the interval between the primary and secondary mirrors.

8. The adaptive lens for a coaxial reflective optical system according to claim 1, characterized in that: The connecting ends of the upper and lower support rods are glued to the secondary mirror support rods (8) and fixed with fasteners.

9. The adaptive lens for a coaxial reflective optical system according to claim 1, characterized in that: The prism (9) can be installed on the outer side wall of any corner of the main mirror support structure (16) according to requirements, and can be glued and fixed to the side wall.

10. An adaptive lens for a coaxial reflective optical system according to any one of claims 1 to 9, characterized in that: The adjusting gasket (2), the lower support rod embedding (8), the secondary mirror support seat embedding (14), the secondary mirror support rod embedding (8) and the secondary mirror support rod connection embedding (13) are all made of 4J32 material whose linear expansion coefficient matches that of SIC material.

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