Wide-temperature self-adaptive off-axis telescopic system based on translation kinematic pair unloading

Abstract

The invention provides a wide-temperature self-adaptive off-axis telescopic system based on translation kinematic pair unloading. The wide-temperature self-adaptive off-axis telescopic system comprises an optical system, an unloading mechanism and a mounting platform, a main reflector assembly and an auxiliary reflector assembly in the optical system are oppositely arranged on a bottom plate. The bottom plate is connected with the mounting platform, and the bottom plate and the mounting platform are made of two materials with different thermal expansion coefficients; the unloading mechanism is arranged between the bottom plate and the mounting platform; a fixed part and a moving part of a translational motion pair of the unloading mechanism are respectively mounted on the bottom plate and the mounting platform; when the temperature changes, the bottom plate and the mounting platform generate different scales of expansion, the translational motion pair generates relative motion along with the expansion amount difference of the bottom plate and the mounting platform, and the expansion amount difference is compensated by the motion freedom degree of the translational motion pair so as to realize thermal stress unloading. The thermal deformation of materials with different thermal expansion coefficients is offset by using the degree of freedom of motion of the unloading mechanism, and a layer of buffer bridge is established between an optical system and an installation environment, so that the product is self-adaptive in a wide temperature range, and the optical effect is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of Cassegrain optical systems, and in particular to a wide temperature adaptive off-axis telescope system based on translational kinematic pair unloading. Background Art

[0002] Compared with the common transmissive optical system in the optical field, the off-axis reflective telescope system has advantages, but it also has practical problems such as difficulty in processing and installation. It has very high requirements for the processing accuracy of optical elements and structural parts, and even higher requirements for the installation accuracy of process personnel during installation. At the same time, it has more stringent requirements on the use environment and is very sensitive to changes in ambient temperature.

[0003] With the development of the optical industry, optical systems are developing towards large aperture, high precision and high stability. As the aperture increases, the spatial size of the optical system will also increase. The thermal expansion increases with the product size, temperature change and thermal expansion coefficient of the material. The thermal expansion directly affects the relative position of each optical element. Therefore, under the same material and the same ambient temperature change, the larger the aperture of the optical system, the greater the impact of temperature.

[0004] In order to ensure the effect of the optical system, the materials of optical components and structural parts are developing in the direction of the smaller the thermal expansion coefficient, the better. The thermal expansion coefficient of commonly used materials for optical components, such as quartz glass, can reach 3×10 -8 ·K -1 The thermal expansion coefficient of commonly used structural materials such as Invar alloy can reach 0.5×10 -6 ·K -1 .

[0005] Generally speaking, the lower the thermal expansion coefficient of a material, the more expensive it is. When designing an optical system, materials with low thermal expansion coefficients can be used in the design of the optical system itself, but any optical system must be installed on a stable mounting platform. Based on economic and practical considerations, the mounting platform can often only be a stable base made of some common materials such as aluminum alloy, steel, etc.

[0006] The significant difference in thermal expansion coefficients between the mounting platform material and the optical system material brings about a new problem. When materials with different thermal expansion coefficients are connected, due to the different thermal expansion capabilities of the materials, large thermal stress will appear at the connection when the temperature changes, causing deformation of the materials. The deformation of the materials will cause relative position deviations between the optical elements, thereby reducing the final optical effect. This phenomenon is particularly obvious in large-aperture off-axis reflective telescope systems. Accordingly, the present invention proposes a wide temperature adaptive off-axis telescope system based on translational kinematic unloading with wide temperature adaptability. Summary of the invention

[0007] Based on the above description, the present invention provides a wide temperature adaptive off-axis telescope system based on translational motion joint unloading, so as to solve the technical problem existing in the prior art that after materials with different thermal expansion coefficients are connected in the existing large-aperture off-axis reflective telescope system, when the temperature changes, due to the different thermal expansion capabilities of the materials, large thermal stress will appear at the connection, causing deformation of the material, and the deformation of the material will cause relative position deviation between the optical elements, thereby reducing the final optical effect.

[0008] The technical solution of the present invention to solve the above technical problems is as follows:

[0009] The present invention provides a wide temperature adaptive off-axis telescope system based on translation motion pair unloading, comprising: an optical system, an unloading mechanism and a mounting platform;

[0010] The optical system comprises a main reflector assembly, a secondary reflector assembly and a bottom plate, wherein the main reflector assembly and the secondary reflector assembly are arranged on the bottom plate relative to each other to form a corresponding off-axis telescopic optical system; the bottom plate is used to be connected to the mounting platform;

[0011] The base plate and the mounting platform are made of two materials with different thermal expansion coefficients;

[0012] The unloading mechanism is arranged between the base plate and the mounting platform, and includes a plurality of translational motion pairs; the fixed part and the moving part of the translational motion pairs are respectively installed on the base plate and the mounting platform; when the temperature changes, the base plate and the mounting platform produce expansions of different magnitudes, and the translational motion pairs produce relative movement with the difference in the expansion amount of the base plate and the mounting platform, and the difference in the expansion amount is compensated by the movement freedom of the translational motion pairs to realize the unloading of thermal stress.

[0013] Based on the above technical solution, the present invention can also be improved as follows.

[0014] Furthermore, the base plate is made of a material with a low expansion coefficient.

[0015] Furthermore, any of the translational kinematic pairs is a single-degree-of-freedom translational kinematic pair.

[0016] Furthermore, the fixed part and the moving part of any of the translational motion pairs are respectively made of the same material as the base plate and the mounting platform;

[0017] The moving part can move relative to the fixed part to adapt to the difference in thermal expansion between the base plate and the mounting platform when the temperature changes.

[0018] Furthermore, the number of the translational motion pairs is four; and the four translational motion pairs are arranged in a cross shape in the horizontal direction.

[0019] Furthermore, the motion axes of one set of translational motion pairs in the X direction and another set of translational motion pairs in the Y direction are both set at an angle, and the initial angle of the two coaxial lines is determined according to the structural parameters and the lateral clearance of the translational motion pairs, respectively, and the calculation formula is as follows:

[0020] ;

[0021] ;

[0022] in, is the lateral clearance of the X-axis translation pair, H is the center distance of the X-axis coaxial translation pair, is the initial angle of the coaxial line in the X direction;

[0023] is the lateral clearance of the Y-axis translation pair, V is the center distance of the Y-axis coaxial translation pair, is the initial angle of the coaxial line in the Y direction.

[0024] Furthermore, the wide temperature adaptive off-axis telescope system based on translational kinematic pair unloading further includes a horizontal pre-tightening mechanism and a vertical pre-tightening mechanism;

[0025] A horizontal pre-tensioning mechanism and a vertical pre-tensioning mechanism are respectively provided on both sides of the bottom plate. The horizontal pre-tensioning mechanism is used to eliminate the horizontal gap of the unloading mechanism in the vertical direction; the vertical pre-tensioning mechanism is used to eliminate the vertical gap of the unloading mechanism in the horizontal direction.

[0026] Furthermore, the wide temperature adaptive off-axis telescope system based on translational kinematic pair unloading also includes a normal preload mechanism;

[0027] A plurality of normal pre-tightening mechanisms are arranged at intervals on a side of the bottom plate away from the mounting platform, and are used to eliminate the normal gap of the unloading mechanism.

[0028] Furthermore, there are eight normal preload mechanisms;

[0029] Two of the eight normal pre-tightening mechanisms form a group, and the four groups of normal pre-tightening mechanisms are respectively located at the four peripheral edges of the bottom plate.

[0030] Compared with the prior art, the technical solution of this application has the following beneficial technical effects:

[0031] The wide temperature adaptive off-axis telescope system based on translational kinematic pair unloading provided by the present invention comprises an optical system, an unloading mechanism and a mounting platform, wherein the optical system comprises a main reflector assembly, a sub-reflector assembly and a base plate, wherein the main reflector assembly and the sub-reflector assembly are arranged on the base plate relatively to form a corresponding off-axis telescope optical system; the base plate is used to connect with the mounting platform; the base plate and the mounting platform are made of two materials with different thermal expansion coefficients; the unloading mechanism is arranged between the base plate and the mounting platform, and the unloading mechanism comprises a plurality of translational kinematic pairs; the fixed part and the moving part of the translational kinematic pair are respectively mounted on the base plate and the mounting platform; when the temperature changes, the base plate and the mounting platform generate expansion of different scales, and the translational kinematic pair generates relative movement with the difference in the expansion amount of the base plate and the mounting platform, and the difference in the expansion amount is compensated by the movement freedom of the translational kinematic pair to realize the unloading of thermal stress.

[0032] The present invention connects materials with different thermal expansion coefficients through an unloading mechanism, and uses the movement freedom of the unloading mechanism to offset the thermal deformation of materials with different thermal expansion coefficients, thereby establishing a buffer bridge between the precisely designed optical system and the common installation environment, so that the product can adapt itself within a wide temperature range, realize thermal stress unloading, and ensure its optical effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A schematic structural diagram of a wide temperature adaptive off-axis telescope system based on translational kinematic pair unloading provided by an embodiment of the present invention;

[0034] Figure 2 A schematic diagram of the decomposed structure of a wide temperature adaptive off-axis telescope system based on translational kinematic pair unloading provided by an embodiment of the present invention;

[0035] Figure 3 It is a schematic diagram of the deformation of the system when there is no unloading mechanism and no unloading measures are taken;

[0036] Figure 4 A schematic diagram of the arrangement of four translational motion pairs arranged in a cross shape in a wide temperature adaptive off-axis telescope system based on translational motion pair unloading provided by an embodiment of the present invention;

[0037] Figure 5 A schematic diagram of the structure of a horizontal pre-tightening mechanism provided by an embodiment of the present invention;

[0038] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0039] 1. Optical system; 11. Main reflector assembly; 12. Sub-reflector assembly; 13. Bottom plate;

[0040] 2. Unloading mechanism; 21. Translation motion pair;

[0041] 3. Installation platform;

[0042] 4. Horizontal preload mechanism; 41. Spring; 42. Fixed parts; 43. Center guide rod;

[0043] 5. Vertical preload mechanism;

[0044] 6. Normal preload mechanism. DETAILED DESCRIPTION

[0045] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "provided with", "connected", etc. should be understood in a broad sense. For example, "connected" 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, an indirect connection through an intermediate medium, or the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] 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 drawings of the present invention. Obviously, the described embodiments are 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 creative work are within the scope of protection of the present invention.

[0047] The Cassegrain optical system is a double-mirror optical system composed of a primary and secondary mirror. Because it completely relies on the reflection of light to achieve the deflection of light, there is no chromatic aberration phenomenon that is widely present in transmission optical systems. And because it completely relies on the reflection principle, it can reduce the absorption of optical materials to the energy of the light beam by increasing the reflectivity of the optical elements, so it is not affected by the energy of the light beam. The Cassegrain optical system can be designed as a telescopic system (afocal system) or a converging system.

[0048] The off-axis reflective telescope system is a common form of Cassegrain optical system. By designing the off-axis amount of the main and secondary reflectors, the main and secondary reflectors can be separated in space, and there is no light beam obstruction. It is widely used in high-power optical systems. By reasonably designing the optical parameters of the main and secondary reflectors, the incident parallel light beam is still output in the form of a parallel light beam, achieving a practical effect similar to that of a telescope system.

[0049] With the development of the optical industry, optical systems are developing towards large aperture, high precision and high stability. As the aperture increases, the spatial size of the optical system will also increase. According to the calculation formula of thermal expansion:

[0050]

[0051] in: is the thermal expansion; is the temperature change; is the size of the optical system; is the thermal expansion coefficient of the material.

[0052] It can be seen that the amount of thermal expansion increases with the increase of product size, temperature change and thermal expansion coefficient of the material; the amount of thermal expansion directly affects the relative position of each optical element. Therefore, under the same material and the same ambient temperature change, the larger the aperture of the optical system, the greater the impact of temperature.

[0053] Based on the aforementioned technical problems and the above background, the present invention provides an adaptive large-aperture off-axis telescope system in a wide temperature range that can achieve thermal stress unloading.

[0054] The following is combined with Figures 1 to 5 The embodiments of the present invention are further described in detail with examples. The following examples are used to illustrate the present invention but cannot be used to limit the scope of the present invention.

[0055] like Figure 1 and Figure 2 As shown, the wide temperature adaptive off-axis telescope system based on translational kinematic joint unloading provided by the embodiment of the present invention specifically includes: an optical system 1, an unloading mechanism 2 and a mounting platform 3.

[0056] like Figure 1 As shown, the optical system 1 includes a main reflector assembly 11, a sub-reflector assembly 12 and a base plate 13. The main reflector assembly 11 and the sub-reflector assembly 12 are arranged on the base plate 13 relatively to form a corresponding off-axis telescopic optical system; the base plate 13 is used to connect with the mounting platform 3.

[0057] The base plate 13 and the mounting platform 3 are made of two materials with different thermal expansion coefficients.

[0058] The material of the bottom plate 13 is a low thermal expansion coefficient material, and in a specific example, it can be Invar alloy. The low thermal expansion coefficient of Invar alloy can further ensure the use temperature range of the entire optical system 1. The mounting platform 3 is a common material used in the actual use environment. The specific materials of the bottom plate 13 and the mounting platform 3 can be determined according to the actual application occasion, and the examples in this embodiment are only shown as examples.

[0059] Specifically, a main reflector assembly 11 and a sub-reflector assembly 12 are formed by fixing the main reflector and the sub-reflector respectively using a mirror holder; to meet the requirements of a wide temperature range, it is necessary to ensure that within the required operating temperature range, the relative positions of the main reflector assembly 11 and the sub-reflector assembly 12 meet the tolerance requirements of the optical design; the main reflector assembly 11 and the sub-reflector assembly 12 are respectively installed on the Invar alloy base plate 13 according to the requirements of the optical design, and the low thermal expansion coefficient of the Invar alloy is used to ensure the operating temperature range of the entire optical system 1.

[0060] In order to meet the versatility of the optical system 1, the optical system 1 needs to be connected to the external mounting platform 3. In order to meet the economic efficiency of the product, the mounting platform 3 in this example is made of a common aluminum alloy material. Since the thermal expansion coefficients of the aluminum alloy mounting platform 3 and the Invar alloy base plate 13 are quite different, if no thermal stress unloading measures are taken, after the temperature changes, the thermal stress will cause the structure to deform and cause the position deviation of the optical element. If no unloading measures are taken, the deformation of the system is as follows: Figure 3 shown.

[0061] Furthermore, in order to ensure that the effect of the optical system 1 is not affected by structural deformation due to material differences within the specified operating temperature range, an unloading mechanism 2 is added between the mounting platform 3 and the Invar alloy base plate 13 to unload thermal stress.

[0062] Specifically, Figure 2 As shown, the unloading mechanism 2 is arranged between the base plate 13 and the mounting platform 3, and the unloading mechanism 2 includes a plurality of translational motion pairs 21; one side of the translational motion pair 21 is installed on the base plate 13, and the other side is installed on the mounting platform 3; when the temperature changes, the base plate 13 and the mounting platform 3 produce expansions of different magnitudes, and the translational motion pair 21 produces relative movement with the difference in expansion amount between the base plate 13 and the mounting platform 3, and the difference in expansion amount is compensated by the movement freedom of the translational motion pair 21 to realize the unloading of thermal stress.

[0063] It should be noted that any translational kinematic joint 21 is a translational kinematic joint with a single degree of freedom.

[0064] The fixed part and the moving part of any translational kinematic pair 21 are respectively made of the same material as the base plate 13 and the mounting platform 3. The moving part can move relative to the fixed part to adapt to the difference in thermal expansion between the base plate 13 and the mounting platform 3 when the temperature changes.

[0065] In an optional embodiment, there are many specific implementation forms of a single-degree-of-freedom translational motion pair. This embodiment is only illustrated by a guide rail and slider structure, which consists of a fixed guide rail and a slider that can move relative to the guide rail. The guide rail and slider of the unloading mechanism 2 are respectively fixed on two different thermal expansion coefficient material structures that need to unload thermal stress. In order to reduce the influence of the guide rail and slider materials on the optical system 1, guide rails and sliders of customized materials are used, and the guide rails and sliders are respectively made of the same material as the connected structure.

[0066] Specifically, in a specific example, the translational motion pair 21 includes a guide rail and a slider; the guide rail is arranged on the mounting platform 3, and the slider is arranged on the base plate 13, and the slider can move relative to the guide rail to drive and adjust the thermal stress deformation of the base plate 13 and the guide rail.

[0067] The guide rail and the mounting platform 3 are made of the same material; the slider and the bottom plate 13 are made of the same material. In a specific example, when the mounting platform 3 is made of aluminum alloy, the corresponding guide rail is also made of aluminum alloy; when the bottom plate 13 is made of Invar alloy, the corresponding slider is also made of Invar alloy.

[0068] Considering the connection stability, the unloading mechanism 2 in this embodiment can be preferably configured as four sets of guide rail slider mechanisms arranged in a cross, and connected between the optical system 1 and the mounting platform 3 according to the center of gravity distribution and optical design requirements of the actual product. When the temperature changes, the optical system 1 and the mounting platform 3 expand in different scales, and the difference in the amount of expansion is compensated by the freedom of movement of the guide rail slider mechanism, thereby realizing the unloading of thermal stress.

[0069] The schematic diagram of the four translational motion pairs 21 arranged in a cross shape is as follows: Figure 4 The four translational motion pairs 21 arranged in a cross shape, namely, four sets of guide rail and slider mechanisms, can not only realize the free unloading of the internal thermal stress of the optical system 1 in the direction of the released freedom of motion, but also limit the optical system 1 by using other constrained freedoms, thereby realizing the stable installation of the optical system 1.

[0070] like Figure 4 As shown, the axes of freedom of motion of one group (two) of translational motion joints 21 in the X direction are collinear, and the axes of freedom of motion of another group (two) of translational motion joints 21 in the Y direction are collinear.

[0071] It should be noted that: combined with the existing single-degree-of-freedom translational motion pair 21 processing precision technology, it can be seen that there must be a microscopic gap between any two moving parts with relative freedom of movement. The position change caused by the gap has a particularly obvious impact on the effect of the optical product. Any motion mechanism that claims to be gapless is unrealistic without taking additional gap-eliminating measures.

[0072] In order to ensure that the stress is unloaded smoothly and the structure is stable, the motion axes of the two sets of translational motion pairs 21 are designed with a certain angle. The initial installation angle of the two axes is determined according to the structural parameters and the lateral clearance of the guide rail slider mechanism. The calculation formula is as follows:

[0073] ;

[0074] ;

[0075] in, is the lateral clearance of the X-axis translation motion pair 21, H is the center distance of the X-axis coaxial translation motion pair 21, is the initial angle of the coaxial line in the X direction;

[0076] is the lateral clearance of the Y-axis translation motion pair 21, V is the center distance of the Y-axis coaxial translation motion pair 21, is the initial angle of the coaxial line in the Y direction.

[0077] Through the above formula, combined with the attached Figure 4 , the initial angles in the X and Y directions can be calculated respectively. Based on the above cross-shaped guide rail slider mechanism configuration with micro-angle deviation, the lateral clearance of the motion mechanism is eliminated by using a small installation angle deviation to ensure the relative stability of the upper optical system 1 relative to the lower installation platform 3. At the same time, the small angle deviation will not bring additional resistance to the unloading of thermal stress.

[0078] In an optional embodiment, in order to further ensure the accuracy of the optical system 1 and improve the ability of the entire product to resist external vibration interference, a pre-tightening mechanism is added between the mounting platform 3 and the optical system 1.

[0079] Specifically, Figure 1 As shown, the wide temperature adaptive off-axis telescope system based on translation motion pair unloading further includes a horizontal pre-tensioning mechanism 4 and a vertical pre-tensioning mechanism 5 .

[0080] A horizontal pre-tensioning mechanism 4 and a vertical pre-tensioning mechanism 5 are respectively provided on both sides of the bottom plate 13 . The horizontal pre-tensioning mechanism 4 is used to eliminate the horizontal gap of the vertical unloading mechanism 2 ; the vertical pre-tensioning mechanism 5 is used to eliminate the vertical gap of the horizontal unloading mechanism 2 .

[0081] In addition, the wide temperature adaptive off-axis telescope system based on translational kinematic joint unloading also includes a normal pre-tightening mechanism 6.

[0082] A plurality of normal pre-tightening mechanisms 6 are arranged at intervals on a side of the bottom plate 13 away from the mounting platform 3 , and are used to eliminate the normal gap of the unloading mechanism 2 .

[0083] In a specific example, if Figure 1 As shown, there are eight normal pre-tensioning mechanisms 6 ; two of the eight normal pre-tensioning mechanisms 6 form a group, and the four groups of normal pre-tensioning mechanisms 6 are respectively located at the four peripheral edges of the bottom plate 13 .

[0084] The above-mentioned pre-tightening mechanism uses the spring 41 to establish elastic force on the mounting platform 3 and the parts to be pre-tightened, and always pulls the slider to the side perpendicular to the freedom of the guide rail-slider mechanism (translational motion pair 21), so as to eliminate the gap between the slider and the guide rail, thereby improving the dynamic stability of the entire product.

[0085] Figure 5 The figure shows a schematic diagram of the structure of the horizontal preload mechanism 4, which is composed of a spring 41, a fixed part 42 and a center guide rod 43. The center guide rod 43 is connected to the fixed part 42, the spring 41 is sleeved on the center guide rod 43, and the part to be preloaded is connected to the spring 41; wherein, the spring 41, as a typical anisotropic linear elastic element in the machinery industry, is particularly suitable in the patent of the present invention.

[0086] The preload force of spring 41 is large and the preload force is easy to adjust. The design parameters and compression amount of spring 41 can be controlled to achieve design matching of the preload force of products of different scales and vibration conditions. The anisotropy of spring 41 makes spring 41 have greater stiffness in its axial direction, so that sufficient preload force can be obtained, and the stiffness in other directions is very low, which can reduce the resistance to thermal stress unloading after the product is preloaded.

[0087] In a specific example, the gravity of a large-aperture off-axis telescope system is about 70kg, and it is required to remain stable under random vibration conditions with a root mean square acceleration of about 1g. According to the calculation formula of the spring stiffness:

[0088]

[0089] in, is the shear modulus of the spring material; is the spring wire diameter; is the middle diameter of the spring; for is the stiffness of the spring.

[0090] Calculations show that the stability of the preload mechanism provided in this embodiment under specified vibration conditions can be ensured by using only 8 springs 41 wound with ordinary spring 41 steel having a linearity of 2.5 mm, an outer diameter of 20 mm, an initial length of 50 mm, and an initial compression of 15 mm.

[0091] The axial direction of the preload mechanism spring 41 is the same as the direction in which the gap needs to be eliminated. In the direction in which free expansion is required to unload stress, since the bending stiffness and shear stiffness of the spring 41 are very small, it is very suitable for use in situations where unidirectional preload is required.

[0092] In summary, the main reflector assembly and the sub-reflector assembly in the wide temperature adaptive off-axis telescope system based on translational motion pair unloading proposed in the embodiment of the present invention are connected by an Invar alloy base plate with a smaller thermal expansion coefficient to ensure the optical effect within a specified temperature range, and four sets of guide rail slider mechanisms in a cross configuration are used to connect the external mounting platform. When the temperature changes, the guide rail slider mechanism enables the Invar alloy base plate and the external mounting platform to achieve their own free expansion, and the difference in expansion is compensated by the freedom of movement of the guide rail slider mechanism.

[0093] Furthermore, considering the processing accuracy of the single-degree-of-freedom translational motion pair, in order to ensure the stability of the optical system in the present invention and to ensure that the large-aperture off-axis telephoto system provided by the present invention is more practical, while using the guide rail slider mechanism to unload thermal stress, a pre-tightening mechanism based on an elastic element is used to eliminate the gap of the guide rail slider mechanism, and the adaptability of the pre-tightening mechanism to the specified vibration environment is ensured by reasonably calculating the design parameters of the elastic element.

[0094] In the description of this specification, the description with reference to the terms "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 embodiment of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example.

[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A wide temperature adaptive off-axis telescope system based on translational kinematic unloading, characterized in that: include: Optical system, unloading mechanism and mounting platform; The optical system comprises a main reflector assembly, a secondary reflector assembly and a bottom plate, wherein the main reflector assembly and the secondary reflector assembly are arranged on the bottom plate relative to each other to form a corresponding off-axis telescopic optical system; the bottom plate is used to be connected to the mounting platform; The base plate and the mounting platform are made of two materials with different thermal expansion coefficients; The unloading mechanism is arranged between the base plate and the mounting platform, and includes a plurality of translational motion pairs; the fixed part and the moving part of the translational motion pairs are respectively installed on the base plate and the mounting platform; when the temperature changes, the base plate and the mounting platform produce expansions of different magnitudes, and the translational motion pairs produce relative movement with the difference in the expansion amount of the base plate and the mounting platform, and the difference in the expansion amount is compensated by the movement freedom of the translational motion pairs to realize the unloading of thermal stress.

2. The wide temperature adaptive off-axis telescope system based on translational kinematic joint unloading according to claim 1, characterized in that: The material of the bottom plate is a low expansion coefficient material.

3. The wide temperature adaptive off-axis telescope system based on translational kinematic joint unloading according to claim 1, characterized in that: Any of the translational kinematic pairs is a single-degree-of-freedom translational kinematic pair.

4. The wide temperature adaptive off-axis telescope system based on translational kinematic joint unloading according to claim 3, characterized in that: The fixed part and the moving part of any of the translational motion pairs are respectively made of the same material as the base plate and the mounting platform; The moving part can move relative to the fixed part to adapt to the difference in thermal expansion between the base plate and the mounting platform when the temperature changes.

5. The wide temperature adaptive off-axis telescope system based on translational kinematic joint unloading according to claim 3 or 4, characterized in that: The number of the translational motion pairs is four; the four translational motion pairs are arranged in a cross shape in the horizontal direction.

6. The wide temperature adaptive off-axis telescope system based on translational kinematic joint unloading according to claim 5, characterized in that: The motion axes of one set of translational motion pairs in the X direction and another set of translational motion pairs in the Y direction are set at an angle. The initial angle of the two coaxial lines is determined according to the structural parameters and the lateral clearance of the translational motion pairs. The calculation formula is as follows: ； ； in, is the lateral clearance of the X-axis translation pair, H is the center distance of the X-axis coaxial translation pair, is the initial angle of the coaxial line in the X direction; is the lateral clearance of the Y-axis translation pair, V is the center distance of the Y-axis coaxial translation pair, is the initial angle of the coaxial line in the Y direction.

7. The wide temperature adaptive off-axis telescope system based on translational kinematic joint unloading according to claim 1, characterized in that: The wide temperature adaptive off-axis telescope system based on translational motion pair unloading further includes a horizontal pre-tightening mechanism and a vertical pre-tightening mechanism; A horizontal pre-tensioning mechanism and a vertical pre-tensioning mechanism are respectively provided on both sides of the bottom plate. The horizontal pre-tensioning mechanism is used to eliminate the horizontal gap of the unloading mechanism in the vertical direction; the vertical pre-tensioning mechanism is used to eliminate the vertical gap of the unloading mechanism in the horizontal direction.

8. The wide temperature adaptive off-axis telescope system based on translational kinematic joint unloading according to claim 7, characterized in that: The wide temperature adaptive off-axis telescope system based on translational kinematic pair unloading also includes a normal preload mechanism; A plurality of normal pre-tightening mechanisms are arranged at intervals on a side of the bottom plate away from the mounting platform, and are used to eliminate the normal gap of the unloading mechanism.

9. The wide temperature adaptive off-axis telescope system based on translational kinematic joint unloading according to claim 8, characterized in that: There are eight normal preload mechanisms; Two of the eight normal pre-tightening mechanisms form a group, and the four groups of normal pre-tightening mechanisms are respectively located at the four peripheral edges of the bottom plate.

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