Optical-mechanical structure of primary and secondary mirrors of Cassegrain telescope system

Abstract

The invention discloses an optical-mechanical structure of primary and secondary mirrors of a Cassegrain telescope system, which comprises a primary mirror support frame and a secondary mirror support frame, the primary mirror support frame and the secondary mirror support frame are both of an annular structure, a primary mirror chamber is arranged in the primary mirror support frame, a primary mirror is arranged in the primary mirror chamber, a secondary mirror chamber is arranged in the secondary mirror support frame, and a secondary mirror is arranged in the secondary mirror chamber. The primary mirror is provided with an inner hole, and a shading cylinder penetrating through the inner hole of the primary mirror is mounted on the primary mirror chamber; wherein the primary mirror supporting frame and the secondary mirror supporting frame are oppositely arranged and are connected together through a plurality of connecting rod assemblies, and the primary mirror and the secondary mirror are both located in an area defined by the connecting rod assemblies. According to the invention, the primary mirror support frame and the secondary mirror support frame are connected through the plurality of connecting rod assemblies, so that the manufacturing cost of the Cassegrain telescope system is greatly reduced, the problem that a blank material is difficult to find is avoided, and a new structural thought is provided for the development of photoelectric detection equipment towards a large aperture.

Description

Technical Field

[0001] The invention belongs to the technical field of photoelectric detection, and in particular relates to an optical-mechanical structure of primary and secondary mirrors of a Cassegrain telescope system. Background Art

[0002] The Cassegrain telescope system is a dual-mirror optical system with a secondary mirror installed between the vertex and the focus of the main mirror. As the application of photoelectric detection equipment in scientific research, national defense and other industries becomes more and more extensive and in-depth, photoelectric detection equipment is also developing towards a longer working distance and higher resolution. In this regard, the Cassegrain telescope system has obvious advantages over the traditional transmission telescope system, and can achieve a larger optical aperture, a longer working distance, and higher imaging quality and resolution, thus being widely used;

[0003] However, as the aperture increases, the influence of factors such as gravity, installation stress and ambient temperature on the optomechanical structure of large-aperture Cassegrain telescope systems becomes increasingly prominent. These factors will affect the surface accuracy of the primary mirror, the position accuracy and stability of the primary and secondary mirrors of the Cassegrain telescope system. As the core components of the Cassegrain telescope system, the position accuracy and stability of the primary and secondary mirrors directly determine the imaging quality, working distance and other system indicators of the photoelectric detection equipment. Therefore, the optomechanical support structure of large-aperture Cassegrain telescope systems is a key technology in the field of photoelectric detection equipment research and development.

[0004] At present, the optical-mechanical support structure of large-aperture Cassegrain telescope systems mostly adopts a barrel structure, that is, the primary and secondary mirrors are connected by a barrel. This structural form is more suitable for small-aperture systems, but as the aperture of the optical system increases, the required barrel blank material size and preparation cost will also increase, and it may even be impossible to find blanks of suitable size, affecting production. In addition, since the barrel structure is a hollow thin-walled structure, most of the material will be cut off during the processing. As the aperture of the optical system increases, the cost-effectiveness of the barrel structure is relatively low. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the prior art and provide an optical-mechanical structure of the primary and secondary mirrors of a Cassegrain telescope system. For a large-aperture Cassegrain telescope system, a primary mirror support frame and a secondary mirror support frame are connected by multiple connecting rod assemblies, which greatly reduces the production cost of the Cassegrain telescope system and avoids the problem of difficulty in finding blanks, thereby providing a new structural idea for the development of photoelectric detection equipment towards large aperture.

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

[0007] An optical-mechanical structure of a primary and secondary mirror of a Cassegrain telescope system, comprising a primary mirror support frame and a secondary mirror support frame, wherein both the primary mirror support frame and the secondary mirror support frame are annular structures, a primary mirror chamber is arranged in the primary mirror support frame, a primary mirror is installed in the primary mirror chamber, a secondary mirror is arranged in the secondary mirror support frame, a secondary mirror chamber is installed in the secondary mirror chamber, the primary mirror has an inner hole, and a light-shielding cylinder penetrating the inner hole of the primary mirror is installed on the primary mirror chamber;

[0008] Wherein, the primary mirror support frame and the secondary mirror support frame are arranged opposite to each other and are connected together by a plurality of connecting rod assemblies. The primary mirror and the secondary mirror are both located in an area surrounded by the plurality of connecting rod assemblies.

[0009] In one embodiment, a plurality of the connecting rod assemblies are evenly spaced along the circumference of the primary mirror support frame and the secondary mirror support frame.

[0010] In one embodiment, the connecting rod assembly includes a hollow pipe and plugs arranged at both ends of the pipe, the plugs at both ends of the pipe are of the same length, the plug is threadedly connected to the pipe, and a threaded hole is also opened in the middle of the plug.

[0011] In one embodiment, a plurality of glue injection grooves and pressing grooves are provided on the inner wall of the main mirror chamber, a main mirror pressing block in contact with the side surface of the main mirror is installed in the pressing groove, RTV silicone rubber is injected in the gap between the main mirror and the glue injection groove, and the main mirror pressing block is gap-matched with the side surface of the main mirror. Through this embodiment, the main mirror is flexibly installed in the main mirror chamber to avoid rigid contact, and the stress generated by the deformation of the main mirror chamber is isolated from being transmitted to the main mirror, so that the surface accuracy of the main mirror can be maintained to the maximum extent.

[0012] In one embodiment, the bottom surface of the primary mirror chamber is provided with a plurality of supporting points in contact with the end surface of the primary mirror, and the diameter of the distribution circle of the plurality of supporting points is D1 is the inner diameter of the main mirror, and D3 is the outer diameter of the main mirror. Through this implementation, the influence of gravity on the surface shape of the main mirror is minimized.

[0013] In one embodiment, the secondary mirror is gap-matched with the secondary mirror chamber, and a secondary mirror pressing ring for fixing the secondary mirror is further provided in the secondary mirror chamber.

[0014] In one embodiment, a secondary mirror adjustment seat is further installed at the end of the secondary mirror chamber away from the primary mirror, and the end of the secondary mirror adjustment seat close to the primary mirror is a conical structure. A plurality of adjustment top screws distributed along the circumference of the secondary mirror adjustment seat are installed on the secondary mirror support frame, and the adjustment top screws extend along the radial direction of the secondary mirror adjustment seat. The end of the adjustment top screw close to the secondary mirror adjustment seat has a conical surface matching the conical structure of the secondary mirror adjustment seat. Through this embodiment, the installation and adjustment efficiency of the secondary mirror is effectively improved.

[0015] In one embodiment, three groups of spherical sub-gaskets connected to the secondary mirror chamber are further provided on the secondary mirror support frame, and the angles between two adjacent groups of spherical sub-gaskets are 120°. Through this embodiment, the secondary mirror chamber, the spherical sub-gaskets and the secondary mirror support frame are all in surface contact, so that the entire telescope system has higher stability and reliability.

[0016] In one embodiment, an adjustment seat is installed on the secondary mirror support frame, and the adjustment seat has four protruding mounting blocks. Each of the mounting blocks is provided with a screw hole, and each of the screw holes is provided with an adjustment top screw.

[0017] In one embodiment, the primary mirror chamber and the secondary mirror chamber are both made of indium steel material.

[0018] The beneficial effects of the present invention are:

[0019] (1) The primary mirror support frame and the secondary mirror support frame are connected by multiple connecting rod assemblies, which greatly reduces the production cost of the Cassegrain telescope system and avoids the problem of difficulty in finding blanks, providing a new structural idea for the development of optoelectronic detection equipment towards large apertures.

[0020] (2) Both the primary mirror and the secondary mirror adopt a flexible mounting structure, which isolates the stress generated by the deformation of the primary mirror chamber and the secondary mirror chamber from being transmitted to the primary mirror and the secondary mirror, thereby maximally maintaining the surface accuracy of the primary mirror and the secondary mirror.

[0021] (3) The distribution circle diameter of the support points set on the primary mirror chamber is the average value of the inner hole diameter and the outer circle diameter of the primary mirror, so that the gravity acting on the primary mirror has the least effect on its surface shape. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be described in more detail below based on embodiments and with reference to the accompanying drawings, wherein:

[0023] Figure 1 A schematic structural diagram of an embodiment of the present invention is shown;

[0024] Figure 2 Shows Figure 1 A schematic diagram of the local enlarged structure at point A in the middle;

[0025] Figure 3 A schematic structural diagram (stereoscopic diagram) of an embodiment of the present invention is shown;

[0026] Figure 4 A schematic diagram showing the structure of the connecting rod assembly of the present invention is shown;

[0027] Figure 5 A schematic diagram of the primary mirror assembly structure of the present invention is shown;

[0028] Figure 6 The structural schematic diagram of the main mirror chamber of the present invention is shown;

[0029] Figure 7 A schematic diagram showing the distribution structure of the support points on the primary mirror chamber of the present invention is shown;

[0030] In the drawings, like reference numerals are used for like parts. The drawings are not necessarily to scale.

[0031] Reference numerals:

[0032] 1-primary mirror, 2-secondary mirror, 3-primary mirror chamber, 4-secondary mirror chamber, 5-connecting rod assembly, 6-secondary mirror support frame, 7-primary mirror support frame, 8-secondary mirror adjustment seat, 9-adjustment top screw, 10-adjustment seat, 11-spherical auxiliary gasket, 12-light shielding tube, 13-secondary mirror pressure ring, 14-mounting block, 15-primary mirror pressure block, 301-glue injection groove, 302-primary mirror chamber mounting hole, 303-support point, 304-process disassembly and assembly hole, 305-pressure groove, 501-pipe, 502-plug. DETAILED DESCRIPTION

[0033] The present invention will be further described below in conjunction with the accompanying drawings.

[0034] The present invention provides an optical-mechanical structure of primary and secondary mirrors of a Cassegrain telescope system, comprising a primary mirror support frame 7 and a secondary mirror support frame 6, both of which are annular structures, a primary mirror chamber 3 is arranged in the primary mirror support frame 7, a primary mirror 1 is installed in the primary mirror chamber 3, a secondary mirror chamber 4 is arranged in the secondary mirror support frame 6, a secondary mirror 2 is installed in the secondary mirror chamber 4, the primary mirror 1 has an inner hole, and a light shielding tube 12 penetrating the inner hole of the primary mirror 1 is installed on the primary mirror chamber 3;

[0035] The primary mirror support frame 7 and the secondary mirror support frame 6 are arranged opposite to each other and are connected together by a plurality of connecting rod assemblies 5. The primary mirror 1 and the secondary mirror 2 are both located in the area surrounded by the plurality of connecting rod assemblies 5.

[0036] It should be noted that if Figures 1 to 3 As shown, in this embodiment, the primary mirror support frame 7 and the secondary mirror support frame 6 are connected by 10 connecting rod assemblies 5, and there is no need to use lens barrel blank materials of corresponding sizes, which greatly reduces the production cost of the Cassegrain telescope system and avoids the problem of difficulty in finding blank materials. It provides a new structural idea for the development of photoelectric detection equipment towards large apertures. In order to ensure the stability of the connection between the primary mirror support frame 7 and the secondary mirror support frame 6, a suitable number of connecting rod assemblies 5 can be set according to the specific aperture of the Cassegrain telescope system. The connecting rod assemblies 5 can be processed in batches. Even when facing telescope systems with different apertures, different numbers of connecting rod assemblies 5 can be set, which effectively improves the processing efficiency.

[0037] Specifically, a plurality of connecting rod assemblies 5 are evenly spaced along the circumference of the primary mirror support frame 7 and the secondary mirror support frame 6, so that the force on each connecting rod assembly 5 is more uniform, the number of connecting rod assemblies 5 is reduced, and the structural strength of the entire telescope system is ensured;

[0038] In one embodiment, Figure 4 As shown, the connecting rod assembly 5 includes a hollow tube 501 and plugs 502 arranged at both ends of the tube 501. The plugs 502 at both ends of the tube 501 have the same length. The plug 502 is threadedly connected to the tube 501, and a threaded hole is also provided in the middle of the plug 502, that is, internal threads are provided at both ends of the hollow tube 501, and the plug 502 is installed on the tube 501 by threaded connection. The threaded hole provided in the middle of the plug 502 is used to be connected to the primary mirror support frame 7 or the secondary mirror support frame 6 as a whole. The tube 501 and the plug 502 are both made of indium steel material. In the process of installing the plug 502, the plug 502 can be first installed in the tube 501, and then the length of the plug 502 can be finely trimmed to ensure that the length is consistent, so as to reduce assembly errors.

[0039] In one embodiment, a plurality of glue injection grooves 301 and pressing grooves 305 are provided on the inner wall of the primary mirror chamber 3, a primary mirror pressing block 15 in contact with the side surface of the primary mirror 1 is installed in the pressing groove 305, RTV silicone rubber is injected into the gap between the primary mirror 1 and the glue injection grooves 301, and the primary mirror pressing block 15 is gap-matched with the side surface of the primary mirror 1;

[0040] Specifically, Figure 5 and Figure 6 As shown, eight glue injection grooves 301 and four pressing grooves 305 are provided on the inner wall of the primary mirror chamber 3, and the glue injection grooves 301 and the pressing grooves 305 are evenly spaced along the circumference of the primary mirror chamber 3, and the pressing grooves 305 are located between the glue injection grooves 301. The primary mirror support frame 7 is made of titanium alloy material, the primary mirror 1 is made of microcrystalline glass material, and the primary mirror chamber 3 is made of indium steel. When the primary mirror 1 is installed in the primary mirror chamber 3, RTV silicone rubber is injected into the glue injection grooves 301 of the primary mirror chamber 3, so that the primary mirror 1 and the primary mirror chamber 3 form a clearance fit, and the fitting clearance can be The primary mirror pressing block 15 is calculated based on the temperature limit value of the storage environment. The primary mirror pressing block 15 and the side surface of the primary mirror 1 are matched with clearance to avoid rigid contact, and the stress generated by the deformation of the primary mirror chamber 3 is isolated from being transmitted to the primary mirror 1, so as to maintain the surface accuracy of the primary mirror 1 to the maximum extent. The bottom surface of the primary mirror chamber 3 is also provided with a plurality of process disassembly holes 304, which are convenient for disassembly and assembly of the primary mirror 1 when maintaining the telescope system. The end surface of the primary mirror chamber 3 is also provided with a plurality of primary mirror chamber mounting holes 302, so as to connect with the primary mirror support frame 7 by using the primary mirror chamber mounting holes 302;

[0041] Furthermore, if Figure 7 As shown, the bottom surface of the primary mirror chamber 3 is provided with a plurality of supporting points 303 in contact with the end surface of the primary mirror 1, and the diameter of the distribution circle of the plurality of supporting points 303 is D1 is the inner diameter of the primary mirror 1, and D3 is the outer diameter of the primary mirror 1, so that the gravity on the surface of the primary mirror 1 has the least influence on the surface shape of the primary mirror 1;

[0042] In one embodiment, Figure 2 As shown, the secondary mirror 2 and the secondary mirror chamber 4 are gap-matched, and a secondary mirror pressing ring 13 for fixing the secondary mirror 2 is arranged in the secondary mirror chamber 4, that is, the secondary mirror 2 also adopts a flexible mounting structure, which isolates the stress generated by the deformation of the secondary mirror chamber 4 from being transmitted to the secondary mirror 2, and can maintain the surface accuracy of the secondary mirror 2 to the maximum extent. The secondary mirror chamber 4 is made of indium steel, and the secondary mirror 2 is fixed in the secondary mirror chamber 4 by the secondary mirror pressing ring 13. RTV silicone rubber is injected between the side gaps of the secondary mirror 2 and the secondary mirror chamber 4 to fix them, and the secondary mirror pressing ring 13 is screwed into the secondary mirror chamber 4 until it contacts the secondary mirror 2;

[0043] Furthermore, if Figure 2 and Figure 3 As shown, a secondary mirror adjusting seat 8 is also installed at one end of the secondary mirror chamber 4 away from the primary mirror 1, and an end of the secondary mirror adjusting seat 8 close to the primary mirror 1 is a conical structure, and a plurality of adjusting top screws 9 distributed along the circumference of the secondary mirror adjusting seat 6 are installed on the secondary mirror support frame 6, and the adjusting top screws 9 extend along the radial direction of the secondary mirror adjusting seat 8;

[0044] Specifically, one end of the adjusting top screw 9 close to the secondary mirror adjusting seat 8 has a conical surface matching the conical structure of the secondary mirror adjusting seat 8, and the secondary mirror supporting frame 6 is also provided with three groups of spherical auxiliary gaskets 11 connected to the secondary mirror chamber 4, and the angles between two adjacent groups of spherical auxiliary gaskets 11 are both 120°, and the secondary mirror supporting frame 6 is installed with an adjusting seat 10, and the adjusting seat 10 has four protruding mounting blocks 14, each of which is provided with a screw hole, and each screw hole is provided with an adjusting top screw 9;

[0045] It should be noted that, each of the four protruding mounting blocks 14 is provided with an adjusting top screw 9, and two opposite adjusting top screws 9 are on the same axis, that is, the four adjusting top screws 9 form two groups of adjusting components, and the axes of the two groups of adjusting components are perpendicular to each other, that is, the two adjusting top screws 9 on the same axis rotate in the same direction, that is, when one adjusting top screw 9 is screwed in, the other adjusting top screw 9 retreats, so that the secondary mirror adjustment seat 8 is pushed by the adjusting top screw 9 to translate along the direction of the axis, thereby driving the secondary mirror 2 to translate, realizing the translation adjustment function, and rotating the two adjusting top screws 9 on another vertical axis can realize the translation adjustment in another orthogonal direction;

[0046] At the same time, since the end of the adjusting top screw 9 close to the secondary mirror adjusting seat 8 has a conical surface matching the conical structure of the secondary mirror adjusting seat 8, that is, the conical surface is tangent to the conical structure, the secondary mirror 2 is prevented from being deflected at an angle under the action of gravity and thus "bowing" during the translation adjustment process;

[0047] At the same time, the spherical auxiliary gasket 11 reserves a trimming margin, and the trimming amount can be measured by a laser interferometer during assembly for trimming. By trimming the thickness of the three groups of spherical auxiliary gaskets 11 by equal amounts, the translation adjustment of the secondary mirror 2 along the central axis can be realized, and by trimming the thickness of the three groups of spherical auxiliary gaskets 11 by unequal amounts, the angular deflection adjustment of the secondary mirror 2 around any axis perpendicular to the central axis, that is, the rotational freedom of two orthogonal axes, can be realized to realize a 5-degree-of-freedom adjustment function, including two orthogonal translational degrees of freedom perpendicular to the central axis, the translational degrees of freedom along the central axis, and the two orthogonal rotational degrees of freedom perpendicular to the central axis, so as to improve the assembly efficiency;

[0048] At the same time, the spherical auxiliary gasket 11 makes the secondary mirror chamber 4, the spherical auxiliary gasket 11 and the secondary mirror support frame 6 all in surface contact, so that the entire telescope system has high stability and reliability;

[0049] In one embodiment, the light shielding tube 12 is machined with fine pitch threads inside and outside, and is oxidized and blackened to eliminate stray light;

[0050] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "bottom", "top", "front", "back", "inside", "outside", "left", "right", etc. 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 device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0051] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in a manner different from that described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be used in other described embodiments.

Claims

1. An optical-mechanical structure of primary and secondary mirrors of a Cassegrain telescope system, characterized in that: It comprises a primary mirror support frame and a secondary mirror support frame, both of which are annular structures, a primary mirror chamber is arranged in the primary mirror support frame, a primary mirror is installed in the primary mirror chamber, a secondary mirror chamber is arranged in the secondary mirror support frame, a secondary mirror is installed in the secondary mirror chamber, the primary mirror has an inner hole, and a light shielding tube penetrating the inner hole of the primary mirror is installed on the primary mirror chamber; Wherein, the primary mirror support frame and the secondary mirror support frame are arranged opposite to each other, and the two are connected together through a plurality of connecting rod assemblies, and the primary mirror and the secondary mirror are both located in the area surrounded by the plurality of connecting rod assemblies.

2. The optical-mechanical structure of the primary and secondary mirrors of a Cassegrain telescope system according to claim 1, characterized in that: The plurality of connecting rod assemblies are evenly spaced along the circumference of the primary mirror support frame and the secondary mirror support frame.

3. The optical-mechanical structure of the primary and secondary mirrors of a Cassegrain telescope system according to claim 1, characterized in that: The connecting rod assembly includes a hollow pipe and plugs arranged at both ends of the pipe. The plugs at both ends of the pipe are of the same length. The plug is threadedly connected to the pipe, and a threaded hole is provided in the middle of the plug.

4. The optical-mechanical structure of the primary and secondary mirrors of a Cassegrain telescope system according to claim 1, characterized in that: A plurality of glue injection grooves and pressing grooves are provided on the inner wall of the main mirror chamber, a main mirror pressing block in contact with the side surface of the main mirror is installed in the pressing groove, RTV silicone rubber is injected in the gap between the main mirror and the glue injection groove, and the main mirror pressing block is gap-matched with the side surface of the main mirror.

5. The optical-mechanical structure of the primary and secondary mirrors of a Cassegrain telescope system according to claim 4, characterized in that: The bottom surface of the primary mirror chamber is provided with a plurality of supporting points in contact with the end surface of the primary mirror, and the diameter of the distribution circle of the plurality of supporting points is D1 is the inner diameter of the main mirror, and D3 is the outer diameter of the main mirror.

6. The optical-mechanical structure of the primary and secondary mirrors of a Cassegrain telescope system according to claim 1, characterized in that: The secondary mirror is clearance-matched with the secondary mirror chamber, and a secondary mirror pressing ring for fixing the secondary mirror is further provided in the secondary mirror chamber.

7. The optical-mechanical structure of the primary and secondary mirrors of a Cassegrain telescope system according to claim 6, characterized in that: A secondary mirror adjustment seat is also installed at the end of the secondary mirror chamber away from the primary mirror, and the end of the secondary mirror adjustment seat close to the primary mirror is a conical structure. A plurality of adjustment top screws distributed along the circumference of the secondary mirror adjustment seat are installed on the secondary mirror support frame, and the adjustment top screws extend along the radial direction of the secondary mirror adjustment seat, and the end of the adjustment top screw close to the secondary mirror adjustment seat has a conical surface matching the conical structure of the secondary mirror adjustment seat.

8. The optical-mechanical structure of the primary and secondary mirrors of a Cassegrain telescope system according to claim 7, characterized in that: The secondary mirror support frame is also provided with three groups of spherical auxiliary gaskets connected to the secondary mirror chamber, and the angle between two adjacent groups of spherical auxiliary gaskets is 120°.

9. The optical-mechanical structure of the primary and secondary mirrors of a Cassegrain telescope system according to claim 7, characterized in that: An adjustment seat is installed on the secondary mirror support frame, and the adjustment seat has four protruding installation blocks. Each of the installation blocks is provided with a screw hole, and each of the screw holes is provided with an adjustment top screw.

10. The optical-mechanical structure of the primary and secondary mirrors of a Cassegrain telescope system according to claim 1, characterized in that: The primary mirror chamber and the secondary mirror chamber are both made of indium steel material.

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