Secondary mirror with high-stable support structure

Abstract

The present application relates to a secondary mirror, in particular to a secondary mirror with high stable support structure. The main problem to be solved is that the support structure of the existing secondary mirror is difficult to achieve ideal balance among high rigidity, low thermal deformation, minimum obstruction and light weight. The secondary mirror of the present application comprises a secondary mirror support shaft, a secondary mirror body, a secondary mirror support plate, a secondary mirror support frame and a secondary mirror light shield. The secondary mirror body is firstly fixed on the secondary mirror support shaft by adhesive, then fixed on the secondary mirror support plate through the secondary mirror support shaft, and fastened by the secondary mirror pressing ring, and then fixed on the secondary mirror support frame through the secondary mirror support plate; the secondary mirror light shield and the thermal control baffle are fixed on the secondary mirror support frame. The secondary mirror of the present application has good force and thermal stability and stray light suppression ability, and can achieve ideal balance among high rigidity, low thermal deformation, minimum obstruction and light weight.

Description

Technical Field

[0001] This invention relates to a secondary mirror, and more specifically to a secondary mirror with a highly stable support structure. Background Technology

[0002] In dual-reflection optical systems, the design of the secondary mirror's support structure is crucial, as its performance directly determines the imaging quality and stability of the optical system. As optical systems evolve towards larger apertures and longer focal lengths, the support structure must maintain the precise orientation of the secondary mirror relative to the primary mirror under multiple factors such as gravity, temperature changes, and mechanical vibrations, while minimizing obstruction of the optical path and integrating stray light suppression measures.

[0003] To meet these requirements, thermal stability is the primary challenge, as fluctuations in ambient temperature can cause thermal deformation of the support structure, disrupting the optical alignment of the primary and secondary mirrors. Vibration stability is equally critical; the support structure must possess high stiffness and damping characteristics to resist vibrations and shocks during transportation, launch, and on-orbit operation, preventing unacceptable misalignment or surface distortion of the secondary mirror. Existing support structures using slender support rods easily amplify the effects of vibration, while innovative flexible support and damping designs, although effective in suppressing resonance and improving dynamic performance, can easily lead to insufficient rigidity. The projection of the support structure into the optical path should be as small as possible. Traditional pressure ring or frame structures increase the outer diameter and obstruction of the secondary mirror. Meanwhile, stray light suppression is indispensable for improving the signal-to-noise ratio of the optical system; therefore, it is also necessary to optimize the cross-sectional shape and surface treatment of the support structure and integrate stray light suppression measures to effectively reduce the scattering energy of non-imaging light.

[0004] In summary, current technology struggles to achieve an ideal balance between multiple objectives, including high stiffness, low thermal deformation, minimal obstruction, and lightweight design. Therefore, there is an urgent need to develop a secondary mirror with a highly stable support structure to comprehensively address the contradictions arising from thermal, mechanical, and optical factors. Summary of the Invention

[0005] The purpose of this invention is to solve the technical problem that existing secondary mirror support structures are difficult to achieve an ideal balance among multiple objectives such as high stiffness, low thermal deformation, minimal obstruction and lightweight, and to provide a secondary mirror with a highly stable support structure.

[0006] To achieve the above objectives, the technical solution provided by this invention is as follows:

[0007] A secondary mirror with a highly stable support structure is characterized by:

[0008] It includes the secondary mirror support shaft, the secondary mirror body, the secondary mirror support plate, the secondary mirror support frame, and the secondary mirror light shield;

[0009] The outer circumferential surface of the secondary mirror support shaft is provided with an annular protrusion section, a first optical axis section, an external thread section, and a second optical axis section in sequence from one end to the other.

[0010] The first optical axis segment has N adhesive retention grooves arranged along the circumferential direction; N≥2;

[0011] The secondary mirror body is fitted onto the first optical axis section and is fixed by adhesive filled in N adhesive grooves, with its front side abutting against the annular protrusion section.

[0012] The inner hole of the secondary mirror support plate is provided with an internal thread section and a shaft hole mating section corresponding to the external thread section and the second optical axis section, respectively; the external thread section and the second optical axis section of the secondary mirror support shaft are inserted into the inner hole of the secondary mirror support plate and mate with the internal thread section and the shaft hole mating section, respectively; the end of the secondary mirror support plate near the annular protrusion section abuts against the back of the secondary mirror body.

[0013] The secondary mirror support frame has a conical structure, with its large-diameter end mounted on an external optical carrier;

[0014] The secondary mirror support plate and the secondary mirror light shield are respectively installed at the small diameter end of the secondary mirror support frame, and the secondary mirror body is located in the inner hole of the small diameter end of the secondary mirror support frame. The secondary mirror light shield is covered on the outer periphery of the front of the secondary mirror body in a circumferential direction.

[0015] Furthermore, the secondary mirror support frame includes a connecting cylinder, a connecting flange, and M support ribs; M ≥ 3;

[0016] The radial dimension of the connecting flange is larger than the radial dimension of the connecting cylinder;

[0017] One end of each of the M support ribs is connected to the outer circumferential surface of the connecting cylinder, and the other end is connected to the inner circumferential surface of the connecting flange.

[0018] The secondary mirror support plate is installed on the end face of the connecting cylinder, and the secondary mirror body is located in the inner hole of the connecting cylinder;

[0019] The secondary mirror's light shield is installed on the connecting cylinder;

[0020] The connecting flange is mounted on the external optical carrier.

[0021] Furthermore, the other end of the support rib is connected to the inner circumferential surface of the connecting flange by two support plates, and the two support plates and the inner circumferential surface of the connecting flange form a hollow triangular area.

[0022] Furthermore, the secondary mirror light shield includes X layers of light shielding tubes coaxially nested from the inside out, and adjacent light shielding tubes are connected by multiple support ribs; X≥1;

[0023] One end of the X-layer light-shielding tube is set flush with the other end, and the other end grows sequentially from the inside to the outside.

[0024] The outer circumferential surface of the X-layer light-shielding tube is provided with clearance grooves for avoiding the support ribs on the secondary mirror support frame.

[0025] The innermost light-shielding cylinder is fitted onto the outer circumference of the connecting cylinder and installed on the end face of the connecting cylinder via a flange.

[0026] Furthermore, the secondary mirror support shaft is provided with stepped openings along the axial direction. The large opening of the opening is located in the first optical axis section and is connected to N glue retention grooves through N glue injection holes. The opening is provided with impurity-removing threads with an overall black surface treatment.

[0027] Furthermore, the secondary mirror support plate includes a support cylinder and a support plate body fitted onto the support cylinder;

[0028] The central through hole of the support cylinder is the inner hole of the secondary mirror support plate; one end of the support cylinder near the annular protrusion section abuts against the back of the secondary mirror body;

[0029] The thickness of the support plate body is less than the length of the support cylinder. Multiple weight-reducing holes are provided on the support plate body along the circumferential direction. Multiple sets of reinforcing ribs are provided on the end face near the annular protrusion section along the circumferential direction. The multiple sets of reinforcing ribs and multiple weight-reducing holes are alternately arranged along the circumferential direction.

[0030] Multiple mounting lugs are provided on the outer circumferential surface of the support plate body along the circumferential direction. The multiple mounting lugs are respectively installed on the small diameter end face of the secondary mirror support frame by bolts.

[0031] Furthermore, a pressure ring mating section is provided at the end of the inner hole of the support cylinder away from the annular protrusion section; the pressure ring mating section is connected to a secondary mirror pressure ring by a thread, and the secondary mirror pressure ring abuts against the end face of the second optical axis section.

[0032] Furthermore, a thermal control baffle is installed on the small-diameter end face of the secondary mirror support frame. The thermal control baffle is fitted onto the support cylinder and is located on the side of the support plate body away from the annular protrusion section.

[0033] Furthermore, the heat control baffle is a circular, flat, thin plate made of aluminum alloy, with a reflective coating sprayed on the light-facing side away from the annular protrusion.

[0034] Furthermore, the secondary mirror support shaft, secondary mirror support plate, and secondary mirror support frame are all made of Invar steel.

[0035] Compared with the prior art, the present invention has the following beneficial technical effects:

[0036] 1. The secondary mirror body is directly supported by the secondary mirror support shaft. The secondary mirror support shaft is a shaft with good rigidity. The material is selected with a coefficient of thermal expansion similar to that of the secondary mirror. This not only ensures that the surface shape of the secondary mirror body will not be distorted due to the deformation of the secondary mirror support shaft under force and heat conditions, but also allows the shaft hole fit to evenly apply the influence of the force and heat environment to the secondary mirror body, so that the secondary mirror body can be uniformly and stably supported.

[0037] 2. The secondary mirror body and the secondary mirror support shaft are fixed by adhesive. The secondary mirror body is a floating support, which avoids direct rigid connection between the secondary mirror body and the secondary mirror support shaft, reduces stress concentration, and improves the assembly success rate. The adhesive method can also resist some force and thermal shock, and improve the support performance of the secondary mirror body.

[0038] 3. The secondary mirror support shaft and the secondary mirror support plate are connected by a near-end thread to handle the main load transfer, while the far-end shaft hole is responsible for the connection accuracy. On the one hand, the cantilever beam formed by the far-end shaft hole and the extremely small gap can achieve flexible deformation transfer. On the other hand, the large gap of the near-end thread can better achieve large displacement and force and heat transfer, ensuring that the influence of the force and heat environment is greatly attenuated after passing through both, reducing the impact transmitted to the secondary mirror body.

[0039] 4. The secondary mirror support plate features a weight-reduction design and a reinforcing rib design, which not only reduces the load on the cantilever beam of the secondary mirror support frame but also strengthens local support, preventing changes in the position and orientation of the secondary mirror body caused by the influence of the force and heat environment.

[0040] 5. The thermal control baffle is a thin plate structure. On the one hand, it can directly block external stray light from shining directly onto the secondary mirror body. On the other hand, the high-emissivity coating can radiate and reflect the heat from external stray light (such as sunlight) onto it, thereby reducing the temperature of the secondary mirror body and preventing thermal deformation of the secondary mirror body.

[0041] 6. The secondary mirror's light shield adopts a multi-layer sleeve structure, which can effectively block external stray light with minimal impact on the secondary mirror. Furthermore, the thin-walled sleeve structure is lightweight, which can also reduce the load on the cantilever beam of the secondary mirror support frame.

[0042] 7. The secondary mirror support frame is made of a material with a low coefficient of thermal expansion, such as Invar steel, which can ensure that the secondary mirror body has good positional accuracy under different force and heat environments. Moreover, the support form of the triangular area can significantly reduce stress concentration without increasing obstruction, thus ensuring support strength and maintaining support stability. Attached Figure Description

[0043] Figure 1 This is a cross-sectional structural diagram of an embodiment of the present invention;

[0044] Figure 2 for Figure 1 A partially enlarged schematic diagram;

[0045] Figure 3 This is a cross-sectional view of the secondary mirror support shaft in an embodiment of the present invention;

[0046] Figure 4 The following is a schematic diagram of the secondary mirror support frame in an embodiment of the present invention: (a) is a front view, and (b) is an axonometric view.

[0047] Figure 5 The diagram shows the structure of the secondary mirror support plate in an embodiment of the present invention. (a) is a sectional view, and (b) is an axonometric view.

[0048] Figure 6 The following is a schematic diagram of the structure of the secondary mirror light shield in an embodiment of the present invention: (a) is a front view and (b) is an axonometric view.

[0049] The annotations in the attached figures are explained as follows:

[0050] 1-Secondary mirror support shaft, 11-Annular protrusion section, 12-First optical axis section, 13-External thread section, 14-Second optical axis section, 15-Glue groove, 16-Glue injection hole, 17-Impurity-removing smooth thread;

[0051] 2-Secondary mirror body;

[0052] 3-Secondary mirror support plate, 31-Internal thread section, 32-Shaft hole mating section, 33-Support cylinder, 34-Support plate body, 35-Reinforcing rib, 36-Weight reduction hole, 37-Mounting plate lug, 38-Pressure ring mating section;

[0053] 4-Secondary mirror support frame, 41-Connecting cylinder, 42-Connecting flange, 43-Supporting rib, 44-Supporting plate;

[0054] 5-Secondary mirror light shield, 51-Light shield tube, 52-Supporting rib, 53-Allowing groove;

[0055] 6-Thermal control baffle. Detailed Implementation

[0056] To make the objectives, advantages, and features of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0057] See Figure 1 and Figure 2 This embodiment provides a secondary mirror with a highly stable support structure. The secondary mirror mainly includes a secondary mirror support shaft 1, a secondary mirror body 2, a secondary mirror support plate 3, a secondary mirror support frame 4, and a secondary mirror light shield 5.

[0058] In this embodiment, generally speaking, the secondary mirror body 2 is first fixed to the secondary mirror support shaft 1 by adhesive, then fixed to the secondary mirror support plate 3 by the secondary mirror support shaft 1, and fastened by the secondary mirror pressure ring. Then, it is fixed to the secondary mirror support frame 4 by the secondary mirror support plate 3. At the same time, the secondary mirror light shield 5 and the heat control baffle 6 are fixed to the secondary mirror support frame 4.

[0059] Specifically, the secondary mirror support shaft 1 can be made of a material with a thermal expansion coefficient similar to that of the secondary mirror body 2. In this embodiment, Invar steel with a smaller thermal expansion coefficient is used.

[0060] See Figure 3 In this embodiment, the outer circumferential surface of the secondary mirror support shaft 1 is divided into four segments: an annular protrusion segment 11, a first optical axis segment 12, an external thread segment 13, and a second optical axis segment 14, which are sequentially arranged from one end to the other. Furthermore, N adhesive grooves 15 are provided circumferentially in the middle of the first optical axis segment 12, where N ≥ 2. In this embodiment, N = 4. A stepped opening is provided axially at the center of the secondary mirror support shaft 1. The larger opening is located within the first optical axis segment 12 and communicates with the four adhesive grooves 15 through four injection holes 16, facilitating the injection of adhesive for bonding the secondary mirror body 2. Simultaneously, a clean-finish thread 17 is provided on the inner circumferential surface of the secondary mirror support shaft 1 at the opening, and the entire surface of the clean-finish thread 17 is treated with a black finish.

[0061] See Figure 1 and Figure 2 The secondary mirror body 2 has a through hole at the center of its end face. The inner diameter of the through hole is adapted to the outer diameter of the first optical axis segment 12. The secondary mirror body 2 is fitted onto the first optical axis segment 12 through its through hole, and the two fit tightly together. At the same time, the secondary mirror body 2 is bonded and fixed by adhesive injected into the adhesive groove 15 through the adhesive injection hole 16. The annular protrusion 11 on the secondary mirror support shaft 1 protrudes from the front of the secondary mirror body 2, so that the front of the secondary mirror body 2 can abut against the annular protrusion 11 to prevent excess adhesive from overflowing.

[0062] See Figure 5 The secondary mirror support plate 3 includes a support cylinder 33 and a support plate body 34 fitted onto the support cylinder 33. The thickness of the support plate body 34 is less than the length of the support cylinder 33. Both the support cylinder 33 and the support plate body 34 are made of Invar steel, which has a low coefficient of thermal expansion.

[0063] The inner bore of the support cylinder 33 is provided with an internal thread section 31, a shaft hole mating section 32, and a pressure ring mating section 38 in sequence from one end to the other. During installation, the pressure ring mating section 38 is located at the end away from the annular protrusion section 11.

[0064] The external thread section 13 and the second optical axis section 14 of the secondary mirror support shaft 1 are inserted into the inner hole of the support cylinder 33, and respectively mate with the internal thread section 31 and the shaft hole mating section 32; the pressure ring mating section 38 is threadedly connected to the secondary mirror pressure ring, which abuts against the end face of the second optical axis section 14, thereby compacting the axial thread gap between the secondary mirror support shaft 1 and the support cylinder 33. The end of the support cylinder 33 near the annular protrusion section 11 abuts against the back of the secondary mirror body 2.

[0065] The support plate body 34 is circular and disc-shaped. Multiple weight-reducing holes 36 are evenly arranged along the circumference of the support plate body 34. Multiple sets of reinforcing ribs 35 are evenly arranged along the circumference of the end face of the support plate body 34 near the annular protrusion 11. In this embodiment, there are four weight-reducing holes 36 and four sets of reinforcing ribs 35, each set including two reinforcing ribs 35 arranged side-by-side. The four sets of reinforcing ribs 35 and the four weight-reducing holes 36 are alternately arranged along the circumference. Multiple mounting ears 37 are evenly arranged along the circumference of the outer circumferential surface of the support plate body 34. In this embodiment, there are four mounting ears 37, which are respectively mounted on the small-diameter end face of the secondary mirror support frame 4 by bolts.

[0066] A heat control baffle 6 is installed on the small-diameter end face of the secondary mirror support frame 4. The heat control baffle 6 is a circular flat thin plate made of lightweight metal material, such as aluminum alloy. The light-facing side of the heat control baffle 6 away from the annular protrusion 11 is coated with a reflective coating, which can reflect heat away. The heat control baffle 6 is fitted on the support cylinder 33 and is located on the side of the support plate body 34 away from the annular protrusion 11.

[0067] See Figure 4 The secondary mirror support frame 4 is a conical structure made of Invar steel with a low coefficient of thermal expansion. It includes a connecting cylinder 41, a connecting flange 42, and M support ribs 43; M≥3; in this embodiment, M=4.

[0068] The radial dimension of the connecting flange 42 is larger than the radial dimension of the connecting cylinder 41; one end of each of the four support ribs 43 is connected to the outer circumferential surface of the connecting cylinder 41, and the other end is connected to the inner circumferential surface of the connecting flange 42 through two support plates 44, and the two support plates 44 and the inner circumferential surface of the connecting flange 42 form a hollow triangular area.

[0069] The connecting flange 42 is mounted on the external optical carrier. The secondary mirror support plate 3 is mounted on the connecting cylinder 41 of the secondary mirror support frame 4, and the secondary mirror body 2 is located in the inner hole of the connecting cylinder 41 of the secondary mirror support frame 4.

[0070] See Figure 6The secondary mirror light shield 5 includes X layers of light shielding tubes 51 coaxially arranged from the inside to the outside, and adjacent layers of light shielding tubes 51 are connected by multiple support ribs 52; X≥1; in this embodiment, X=2; the number of support ribs 52 can be 6, 8, etc., and in this embodiment, 8 support ribs 52 are used as an example. One end of the two layers of light shielding tubes 51 can be flush, or there can be a certain installation or design deviation. The other end of the two layers of light shielding tubes 51 grows sequentially from the inside to the outside and covers the outer periphery of the front of the secondary mirror body 2 in a circumferential direction; the outer periphery of the two layers of light shielding tubes 51 is respectively provided with clearance grooves 53 for avoiding the support ribs 43 on the secondary mirror support frame 4, so as to facilitate installation on the secondary mirror support frame 4; the innermost light shielding tube 51 is sleeved on the outer periphery of the connecting tube 41 and is installed on the end face of the connecting tube 41 through a flange.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. A secondary mirror with a highly stable support structure, characterized in that: It includes a secondary mirror support shaft (1), a secondary mirror body (2), a secondary mirror support plate (3), a secondary mirror support frame (4), and a secondary mirror light shield (5); The outer circumferential surface of the secondary mirror support shaft (1) is provided with an annular protrusion section (11), a first optical axis section (12), an external thread section (13), and a second optical axis section (14) in sequence from one end to the other. The first optical axis segment (12) is provided with N adhesive retention grooves (15) along the circumferential direction; N≥2; The secondary mirror body (2) is fitted onto the first optical axis section (12) and is fixed by adhesive filled in N adhesive grooves (15), with its front side abutting against the annular protrusion section (11). The inner hole of the secondary mirror support plate (3) is provided with an internal thread section (31) and a shaft hole mating section (32) corresponding to the external thread section (13) and the second optical axis section (14), respectively; the external thread section (13) and the second optical axis section (14) of the secondary mirror support shaft (1) are inserted into the inner hole of the secondary mirror support plate (3) and respectively mate with the internal thread section (31) and the shaft hole mating section (32); the end of the secondary mirror support plate (3) near the annular protrusion section (11) abuts against the back of the secondary mirror body (2); The secondary mirror support frame (4) has a conical structure, with its large-diameter end mounted on an external optical carrier; The secondary mirror support plate (3) and the secondary mirror light shield (5) are respectively installed at the small diameter end of the secondary mirror support frame (4), and the secondary mirror body (2) is located in the inner hole of the small diameter end of the secondary mirror support frame (4). The secondary mirror light shield (5) is covered on the outer periphery of the front of the secondary mirror body (2) along the circumferential direction.

2. The secondary mirror with a highly stable support structure according to claim 1, characterized in that: The secondary mirror support frame (4) includes a connecting cylinder (41), a connecting flange (42), and M support ribs (43); M ≥ 3; The radial dimension of the connecting flange (42) is larger than the radial dimension of the connecting cylinder (41); One end of each of the M support ribs (43) is connected to the outer circumferential surface of the connecting cylinder (41), and the other end is connected to the inner circumferential surface of the connecting flange (42); The secondary mirror support plate (3) is installed on the end face of the connecting cylinder (41), and the secondary mirror body (2) is located in the inner hole of the connecting cylinder (41); The secondary mirror light shield (5) is mounted on the connecting cylinder (41); The connecting flange (42) is mounted on an external optical carrier.

3. A secondary mirror with a highly stable support structure according to claim 2, characterized in that: The other end of the support rib (43) is connected to the inner circumferential surface of the connecting flange (42) by two support plates (44), and the two support plates (44) and the inner circumferential surface of the connecting flange (42) form a hollow triangular area.

4. A secondary mirror with a highly stable support structure according to claim 2 or 3, characterized in that: The secondary mirror light shield (5) includes X layers of light shield tubes (51) coaxially arranged from the inside to the outside, and adjacent light shield tubes (51) are connected by multiple support ribs (52); X≥1; One end of the light-shielding tube (51) in layer X is flush with the other end, and the other end grows sequentially from the inside to the outside. The outer circumferential surface of the light-shielding tube (51) of layer X is provided with clearance grooves (53) for avoiding the support ribs (43) on the secondary mirror support frame (4); The innermost light-shielding cylinder (51) is fitted onto the outer circumference of the connecting cylinder (41) and installed on the end face of the connecting cylinder (41) via a flange.

5. A secondary mirror with a highly stable support structure according to claim 4, characterized in that: The secondary mirror support shaft (1) is provided with a stepped opening along the axial direction. The large hole of the opening is located in the first optical axis section (12) and is connected to N glue retention grooves (15) through N glue injection holes (16). The opening is provided with a black-finished smooth thread (17).

6. A secondary mirror with a highly stable support structure according to claim 1, characterized in that: The secondary mirror support plate (3) includes a support cylinder (33) and a support plate body (34) fitted onto the support cylinder (33); The central through hole of the support cylinder (33) is the inner hole of the secondary mirror support plate (3); the end of the support cylinder (33) near the annular protrusion (11) abuts against the back of the secondary mirror body (2); The thickness of the support plate body (34) is less than the length of the support cylinder (33). The support plate body (34) has multiple weight-reducing holes (36) arranged along the circumferential direction. On the end face of the support plate body (34) near the annular protrusion section (11), multiple sets of reinforcing ribs (35) are arranged along the circumferential direction. The multiple sets of reinforcing ribs (35) and multiple weight-reducing holes (36) are arranged alternately along the circumferential direction. The outer circumferential surface of the support plate body (34) is provided with a plurality of mounting lugs (37) along the circumferential direction. The plurality of mounting lugs (37) are respectively installed on the small diameter end face of the secondary mirror support frame (4) by bolts.

7. A secondary mirror with a highly stable support structure according to claim 6, characterized in that: The inner hole of the support cylinder (33) is provided with a pressure ring mating section (38) at the end away from the annular protrusion section (11); the pressure ring mating section (38) is connected to a secondary mirror pressure ring by a thread, and the secondary mirror pressure ring abuts against the end face of the second optical axis section (14).

8. A secondary mirror with a highly stable support structure according to claim 6 or 7, characterized in that: A heat control baffle (6) is installed on the small diameter end face of the secondary mirror support frame (4). The heat control baffle (6) is fitted on the support cylinder (33) and is located on the side of the support plate body (34) away from the annular protrusion section (11).

9. A secondary mirror with a highly stable support structure according to claim 8, characterized in that: The heat control baffle (6) is made of aluminum alloy, and its light-facing side away from the annular protrusion (11) is coated with a reflective coating.

10. A secondary mirror with a highly stable support structure according to claim 1, characterized in that: The secondary mirror support shaft (1), secondary mirror support plate (3), and secondary mirror support frame (4) are all made of Invar steel.

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