Passive noise reduction protective cover for atomic force microscope

Abstract

The utility model provides a passive noise reduction protective cover for an atomic force microscope, and belongs to the technical field of precise instrument protection. Aiming at the problems of incomplete structural isolation, insufficient temperature control capability, inconvenience in operation and the like of the existing atomic force microscope protection device, the utility model provides a totally-enclosed integrated solution. The protective cover adopts a sound-proof housing with an opening in the bottom to construct a closed cavity, and synchronously wraps the atomic force microscope body and the supporting system of the atomic force microscope body. Multi-band noise truncation is realized through the outer structure layer, the composite broadband sound absorption layer and the gradient density sound insulation layer. A semiconductor temperature control module and a spiral noise elimination wiring channel are integrated in the cavity, a double-opening-closing system is combined, and vibration transmission, sound wave interference and temperature drift are effectively restrained in a closed state. According to the scheme, the airtight sealing structure capable of being controlled to be opened and closed, the transparent observation window and the integrated temperature control compensation system are integrated, the device is suitable for providing stable environment isolation protection in a nanoscale measurement scene, and meanwhile operation convenience is taken into consideration.

Description

Technical Field

[0001] This utility model relates to the field of precision instrument protection devices, and in particular to a passive noise reduction protective cover for an atomic force microscope. Background Technology

[0002] Atomic force microscopy (AFM), a key instrument for nanoscale characterization, is highly susceptible to environmental noise interference in its measurement accuracy. Studies have shown that ground vibrations (0.1-100Hz frequency band) can cause probe amplitude shifts exceeding 5nm, airborne acoustic interference (100Hz-10kHz) can generate spurious force feedback of ±0.25N / m, and temperature fluctuations (±1℃) can cause probe thermal drift of 50nm per hour. This means that environmental noise control has become a core challenge in improving the stability of AFM measurements. Traditional AFM noise reduction solutions have two major drawbacks. First, existing protective covers only enclose the microscope body, leaving the microscope's support system, such as the air cushion table or stand, exposed, causing vibrations to be transmitted through the support structure. Second, multi-layered sound insulation structures lack temperature compensation design; experiments show that AFM probe drift reaches 12nm / min when temperature fluctuations are ±0.5℃.

[0003] Therefore, developing an integrated protection system that combines vibration isolation, acoustic barrier, and temperature compensation is crucial for ensuring the sub-nanometer measurement accuracy of atomic force microscopes. Utility Model Content

[0004] In view of the problems of incomplete structure, insufficient thermal stability and complicated operation of existing atomic force microscope protective devices, this utility model proposes a passive noise reduction protective cover for atomic force microscopes that overcomes or at least partially solves the above problems.

[0005] One objective of this invention is to use an integrated, sealed protective cover to isolate the atomic force microscope body, along with its shock-absorbing support system, from the external environment, thereby simultaneously blocking vertical vibrations and horizontal disturbances.

[0006] A further objective of this invention is to integrate temperature control functionality within the protective cover.

[0007] Another further objective of this invention is to integrate circuit management functions into the protective cover.

[0008] Specifically, this utility model provides a passive noise reduction protective cover for an atomic force microscope. The atomic force microscope includes an atomic force microscope body and a shock-absorbing support system located on a support surface for supporting the atomic force microscope body. The passive noise reduction protective cover includes a soundproof shell with an open bottom, such that when in use, the soundproof shell covers the support surface through the bottom of the open bottom to form a sealed cavity inside the soundproof shell, so as to accommodate the atomic force microscope body and the shock-absorbing support system in a manner that does not contact or fix them to any part of the protective cover within the sealed cavity.

[0009] Optionally, the soundproof enclosure includes a frame and soundproof panels respectively fixed to the frame to form the front part, side panels and top cover of the soundproof enclosure;

[0010] Each of the aforementioned sound insulation panels includes:

[0011] The outer structural layer is fixed to the frame;

[0012] A composite broadband sound-absorbing layer is bonded to the inner surface of the outer structural layer; and

[0013] A density gradient sound insulation layer is attached to the inner surface of the composite broadband sound absorption layer.

[0014] Optionally, the composite broadband sound-absorbing layer comprises a lead rubber damping layer and an alumina ceramic plate bonded together.

[0015] Optionally, the front of the soundproof enclosure includes an upper double door and a lower double door, which are used to independently open the upper and lower parts of the sealed cavity, respectively.

[0016] Optionally, each of the upper double door and the lower double door includes two doors respectively hinged to the frame of the soundproof enclosure;

[0017] The passive noise reduction protective cover also includes an opening and closing mechanism corresponding to each of the doors. Each opening and closing mechanism includes a pivot fixed to the frame and a pneumatic support rod with one end connected to the pivot and the other end connected to the door, so that each door can be opened independently and controllably through the pneumatic support rod.

[0018] Optionally, each of the doors has a sealing strip embedded in its frame and a wedge-shaped guide structure provided on the closed contact surface of the two doors.

[0019] Optionally, the upper double doors and / or the lower double doors are provided with light-transmitting observation windows;

[0020] The light-transmitting observation window is formed by a zinc sulfide crystal plate, or by a composite of a zinc sulfide crystal plate and a transparent substrate, and has broadband transmission performance in the visible and infrared bands.

[0021] Optionally, the passive noise reduction protective cover further includes:

[0022] The temperature control compensation module is located in the sealed cavity and embedded in the density gradient sound insulation layer.

[0023] Optionally, the temperature control compensation module includes a semiconductor cooling chip and a temperature distribution plate, used to perform temperature homogenization compensation within the sealed cavity; and / or

[0024] The temperature control compensation module includes a circulating cooling channel, which is disposed in the sealed cavity, and the outlet and inlet of the circulating cooling channel extend out of the soundproof cover to be connected to the cooling fluid source for active heat dissipation.

[0025] Optionally, the passive noise reduction protective cover further includes:

[0026] A spiral wiring channel running through the soundproof enclosure;

[0027] The spiral wiring channel includes a spiral metal tube, a buffer layer wrapped around the outside of the spiral metal tube, and a high-porosity sound-absorbing material filled inside the spiral metal tube.

[0028] This invention provides a passive noise-reducing protective cover for an atomic force microscope (AFM). The cover features a bottom-opening soundproof shell, allowing it to be placed over the support surface of the AFM's vibration-damping support system. This forms a sealed cavity encompassing the AFM body and its vibration-damping support system, without any contact or fixed connection between the AFM body, the vibration-damping support system, or any part of the protective cover. This fully enclosed structure completely isolates the AFM body and its vibration-damping support system from the external environment, creating a structurally complete, sealed, and controllable internal environment. It prevents vertical vibrations from being transmitted to the AFM through the protective cover and also blocks horizontal acoustic disturbances.

[0029] Furthermore, the passive noise reduction protective cover of this utility model is equipped with a temperature control compensation module, which makes up for the deficiency of insufficient thermal stability that may be caused by isolating the external environment.

[0030] Furthermore, the passive noise reduction protective cover of this utility model is equipped with upper and lower double doors and corresponding opening and closing mechanisms, which can quickly (within 15 seconds) complete the switching of operation modes and is easy to operate.

[0031] Furthermore, the passive noise reduction protective cover of this utility model is equipped with a spiral wiring channel, thereby integrating the wiring management function and facilitating the arrangement and use of electrical components inside the protective cover.

[0032] The above description is merely an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this utility model more obvious and understandable, specific embodiments of this utility model are given below.

[0033] The above and other objects, advantages and features of this utility model will become more apparent to those skilled in the art from the following detailed description of specific embodiments of this utility model in conjunction with the accompanying drawings. Attached Figure Description

[0034] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0035] Figure 1 This is a front view of a passive noise reduction protective cover according to an embodiment of the present invention;

[0036] Figure 2 for Figure 1 The side view of the passive noise reduction protective cover shown;

[0037] Figure 3 for Figure 1 A top view of the passive noise reduction protective cover shown;

[0038] Figure 4 For along Figure 1 Schematic diagram of the cross section of the EE line;

[0039] Figure 5 For along Figure 1 A cross-sectional view of the FF line;

[0040] Figure 6 This is a schematic diagram of any double door of a passive noise reduction protective cover according to an embodiment of the present invention and its opening and closing structure;

[0041] Figures 7a to 7d for Figure 6 The diagram shows the process of opening the double door and its opening and closing mechanism.

[0042] Figure 8 A comparison chart showing the noise decibel measurement results with and without the passive noise reduction protective cover of this utility model;

[0043] Figure 9 An exemplary atomic-precision image obtained by atomic force microscopy is shown when using the passive noise-reducing protective cover of this invention. Detailed Implementation

[0044] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0045] To address the above technical problems, this utility model provides a passive noise reduction protective cover 100 for an atomic force microscope.

[0046] An atomic force microscope typically includes an atomic force microscope body 15 and a shock-absorbing support system 17 located on a support surface 18 for supporting the atomic force microscope body 15. The support surface 18 may be, for example, a tabletop, a laboratory bench, etc. The shock-absorbing support system 17 may include a passive shock-absorbing stage 16, such as an air cushion vibration isolation stage, which is supported on the support surface 18 by legs, or may include a tripod.

[0047] Figure 1 A front view of a passive noise-reducing protective cover 100 according to an embodiment of the present invention is shown. Figure 2 for Figure 1 The side view of the passive noise reduction protective cover 100 shown is shown. Figure 3 for Figure 1 The top view of the passive noise reduction protective cover 100 shown is shown. Figure 4 For along Figure 1 A cross-sectional view of the EE line. Figure 5 For along Figure 1 A cross-sectional view of the FF line. See below for reference. Figures 1 to 5 The structure of the passive noise reduction protective cover 100 of this utility model will be described.

[0048] like Figures 1 to 3 As shown, the passive noise reduction protective cover 100 includes a soundproof enclosure 20. The soundproof enclosure 20 has an open bottom, such that when in use, the soundproof enclosure 20 covers the support surface 18 through the open bottom to form a sealed cavity 19 inside the soundproof enclosure 20, so as to accommodate both the atomic force microscope body 15 and the shock absorption support system 17 within the sealed cavity 19, and the atomic force microscope body 15 and the shock absorption support system 17 do not contact or have a fixed connection with any part of the protective cover 100.

[0049] This fully enclosed structure completely isolates the atomic force microscope body 15, along with its shock-absorbing support system 17, from the external environment, forming a structurally complete, sealed, and controllable internal environment. This prevents vertical vibrations from being transmitted to the atomic force microscope through the protective cover 100, while also blocking horizontal acoustic disturbances.

[0050] In some embodiments, the soundproof enclosure 20 may be cuboid in shape, and the dimensions of the sealed cavity 19 formed therein are expressed as W×D×L. These dimensions may be determined based on the dimensions of the atomic force microscope body 15 and its shock-absorbing support system 17 to be housed within the sealed cavity 19, so as to maximize the housing of the atomic force microscope body 15 and its shock-absorbing support system 17, and to ensure that there is no contact or fixed structural connection between the two.

[0051] In some embodiments, the soundproof enclosure 20 may include a frame 1 that serves as the skeleton of the entire protective cover 100, and soundproof panels that are respectively fixed to the frame 1 to form the front portion, side panels 8, and top cover 9 of the soundproof enclosure 20. In other words, the front portion, side panels 8, and top cover 9 of the soundproof enclosure 20 are each composed of soundproof panels, and the edges of each soundproof panel are connected to the frame 1 to fix the soundproof panel.

[0052] In some embodiments, the frame 1 may be a steel plate frame 1 or formed by welding composite aluminum plates.

[0053] like Figure 4 and Figure 5 As shown, each sound insulation panel includes an outer structural layer 10 fixed to the frame 1, a composite broadband sound-absorbing layer 11 adhered to the inner surface of the outer structural layer 10, and a density gradient sound insulation layer 12 adhered to the inner surface of the composite broadband sound-absorbing layer 11. These three components are tightly connected in a sandwich structure to form a multi-stage sound-absorbing structure, thereby improving noise reduction. Those skilled in the art will understand that the inner surface refers to the surface facing the interior of the sealed cavity 19.

[0054] In one specific embodiment, the outer structural layer 10 may be made of stainless steel, such as SUS304 stainless steel. Optionally, the stainless steel sheet may be shot-peened to create an impact-resistant surface to enhance its impact resistance. The thickness of the stainless steel sheet may be in the range of 1–2 mm, for example, 1.2 mm, to ensure its strength.

[0055] In another specific embodiment, the outer structural layer 10 may also be made of plexiglass.

[0056] In some embodiments, the composite broadband sound-absorbing layer 11 may include a lead rubber damping layer and an alumina ceramic plate bonded together, thereby forming a broadband sound barrier. The thickness of the lead rubber damping layer may be in the range of 0.5 to 1.5 mm, for example, 0.8 mm. The thickness of the alumina ceramic plate may be in the range of 1.5 to 3 mm, for example, 2 mm.

[0057] In some embodiments, the density gradient sound insulation layer 12 may be a polyurethane foam layer with varying density gradient.

[0058] See Figure 1 In some embodiments, the front of the soundproof enclosure 20 includes an upper double door 4 and a lower double door 5, which are used to independently open the upper and lower parts of the sealed cavity 19, respectively. Specifically, the upper double door 4 can be used to independently open the upper half of the sealed cavity 19, thereby facilitating operation of the atomic force microscope body 15 inside the sealed cavity 19. The lower double door 5 can be used to independently open the lower half of the sealed cavity 19, thereby facilitating operation of the shock-absorbing support system 17 inside the sealed cavity 19.

[0059] Figure 6 This is a schematic diagram of any double door of a passive noise-reducing protective cover 100 according to an embodiment of the present invention and its opening and closing structure. See also... Figure 6 As shown, each of the upper double doors 4 and the lower double doors 5 includes two doors that are respectively hinged to the frame 1 of the soundproof enclosure 20. Specifically, one side of each door can be hinged to the frame 1 via a hinge 27.

[0060] In some embodiments, the passive noise reduction protective cover 100 may further include an opening and closing mechanism 23 corresponding to each door, for controlling the opening and closing of the double doors. The upper double door 4 and the lower double door 5 and their corresponding opening and closing mechanisms 23 respectively form an independent upper and lower double opening and closing system.

[0061] Each opening and closing mechanism 23 may include a rotating shaft 21 fixed to the frame 1, and a pneumatic strut 22 with one end connected to the rotating shaft 21 and the other end connected to the door, so that each door can be opened independently and controllably through the pneumatic strut 22.

[0062] In some specific embodiments, each door can be opened from 0 to 90 degrees by the pneumatic strut 22.

[0063] Optionally, each door can be opened from 0 to 85 degrees by the pneumatic strut 22.

[0064] The following is combined Figures 7a to 7d The process of opening either the upper double door 4 or the lower double door 5 (hereinafter referred to as the double door) and its opening and closing mechanism 23 is described. When the double door is closed, the piston rod of the pneumatic strut 22 is in the retracted position, as... Figure 7a As shown. When the double doors need to be opened, the piston rod of the pneumatic strut 22 extends under pneumatic power, pushing the door connected to it to open outward until the desired opening degree is reached, as shown. Figure 7b and Figure 7c As shown. It should be noted that, Figure 7b and Figure 7c The diagram only shows the opening process of one of the double doors; those skilled in the art will understand that the opening process of the other door is similar. Finally, Figure 7d This shows the state where both doors are simultaneously opened to their maximum opening. Of course, the two doors in a double door system can be opened or closed simultaneously, or they can be opened or closed independently.

[0065] By using a pneumatic strut 22 as the drive for door opening and closing, the dual opening and closing system of this embodiment can complete the operation mode switching within 15 seconds, and the operation is simple.

[0066] In some further embodiments, the frame 3 of each door may also be fitted with a sealing strip 24, thereby enhancing the airtightness of the protective cover 100 and improving the protective effect.

[0067] In one specific embodiment, the sealing strip 24 may be a magnetic sealing strip 24, which allows the double door to fit more tightly with the frame 1 when closed, thereby enhancing the airtightness of the protective cover 100.

[0068] In some embodiments, the closing contact surfaces of the two opposing doors of each double door may be provided with a wedge-shaped guide structure 25. By providing the wedge-shaped guide structure 25, mutual interference between the two doors is prevented when the double doors are opened and closed, and the opening and closing of the double doors is made smoother, thereby improving the user experience.

[0069] See also Figure 1 and Figure 5 In some embodiments, a light-transmitting observation window 2 may be provided in the upper double door 4 and / or the lower double door 5. The state of the atomic force microscope inside the protective cover 100 can be observed through the light-transmitting observation window 2.

[0070] In some embodiments, the light-transmitting observation window 2 may be made of a zinc sulfide crystal plate, which has broadband transmission properties in the visible and infrared bands.

[0071] In other embodiments, the light-transmitting observation window 2 may be composed of a zinc sulfide crystal plate and a transparent substrate. Specifically, the zinc sulfide crystal plate and the transparent substrate form a sandwich structure, with the interlayer filled with gas. This not only achieves broadband transmission performance in the visible and infrared bands but also enhances heat insulation and sound insulation effects.

[0072] The transparent substrate can be, for example, sapphire glass, and the filling gas can be argon.

[0073] See also Figure 4In some embodiments, the passive noise reduction protective cover 100 may further include a temperature control compensation module 14 for achieving temperature uniformity compensation within the sealed cavity 19. The temperature control compensation module 14 is located within the sealed cavity 19 and embedded in the density gradient sound insulation layer 12. The number of temperature control compensation modules 14 may be one or more, and can be set according to actual application requirements.

[0074] In some embodiments, a controller (not shown in the figure) may be connected to the temperature compensation module 14 to control the operation of the temperature compensation module 14. The controller may be located inside or outside the sealed cavity 19, and this invention does not impose any restrictions on this.

[0075] In some embodiments, the temperature control compensation module 14 is a semiconductor temperature control element, specifically including a semiconductor cooling chip and a vapor chamber. Those skilled in the art should know the connection structure and operating principle of the semiconductor cooling chip and the vapor chamber, which will not be described in detail here.

[0076] In some embodiments, the temperature control compensation module 14 may include a circulating cooling channel (not shown in the figure). The circulating cooling channel is disposed within the sealed cavity 19, and the outlet and inlet of the circulating cooling channel extend outside the soundproof cover 20 to be connected to a cooling fluid source for active heat dissipation.

[0077] In one specific embodiment, the circulating cooling channel is a circulating water channel to form a circulating water cooling system.

[0078] The circulating cooling channel can be set in a position within the sealed cavity 19 as needed, for example, on the back side of the sealed cavity 19.

[0079] In some embodiments, the temperature control compensation module 14 may include a thermoelectric cooler, a vapor chamber, and a circulating cooling channel. The circulating cooling channel and the thermoelectric cooler work together to form an active heat dissipation system.

[0080] In this embodiment of the utility model, a temperature control compensation module 14 is added inside the passive noise reduction protective cover 100 to make up for the deficiency of insufficient thermal stability that may be caused by isolating the external environment.

[0081] See Figure 2 In some embodiments, the passive noise reduction protective cover 100 may further include a spiral wiring channel 26. The spiral wiring channel 26 extends through the sound insulation cover 20 and is used to bring out the connection wires of electrical components within the sealed cavity 19.

[0082] In one specific embodiment, the spiral wiring channel 26 is disposed on and penetrates the side plate 8 of the soundproof enclosure 20. Specifically, an opening is provided in the side plate 8, and the spiral wiring channel 26 is placed in the opening.

[0083] By setting the spiral wiring channel 26, the passive noise reduction protective cover 100 of this utility model embodiment integrates the wiring management function, which facilitates the arrangement and use of electrical components inside the protective cover 100.

[0084] like Figure 2 As shown, in some embodiments, the spiral wiring channel 26 includes a spiral metal tube 6, a buffer layer (not shown) wrapped around the spiral metal tube 6, and a high-porosity sound-absorbing material 7 filled inside the spiral metal tube 6, thereby forming a multi-stage sound-absorbing structure to prevent acoustic disturbances from being transmitted into the sealed cavity 19 through the spiral wiring channel 26.

[0085] In some embodiments, the passive noise reduction protective cover 100 may further include an illumination module 13 disposed within the sealed cavity 19 for illuminating the sealed cavity 19 to facilitate observation and operation of the atomic force microscope. The illumination module 13 may be disposed at an appropriate position within the sealed cavity 19 according to actual illumination needs, for example, at the inner center of the top cover 9.

[0086] In one specific embodiment, the lighting module 13 may be an LED element.

[0087] The passive noise reduction protective cover 100 of this utility model will be further described below with reference to specific embodiments.

[0088] Example 1

[0089] The passive noise reduction protective cover 100 provided in this embodiment has the following structure: Figures 1 to 7d As shown. The external dimensions of the sealed cavity 19 are determined entirely by the dimensions of the internal atomic force microscope body 15 and its passive damping stage 16. The frame 1 can be made of steel plate frame 1 or welded composite aluminum plate. The sandwich structure multi-level composite sound insulation board has an outer structural layer 10 made of 1.2mm thick SUS304 stainless steel plate shot peened to form an impact-resistant surface, a middle layer of 0.8mm lead rubber layer and 2mm alumina ceramic plate to form a composite wide-band sound-absorbing layer 11, and an inner layer of polyurethane foam layer 12 with varying density. The outer structural layer 10 can also be made of plexiglass. The temperature control compensation module 14 includes a combination structure of semiconductor cooling chip and heat spreader, and maintains the set temperature through a PID controller.

[0090] The protective cover 100 features a double-opening system, which can be equipped with a pneumatic strut 22 to achieve controllable opening at an angle of 0-85°. The door frame 3 is fitted with a magnetically adsorbed sealing strip 24, and a wedge-shaped guide structure 25 is provided on the closed contact surface. Specifically, the upper double door 4 integrates a zinc sulfide crystal light-transmitting observation window 2, which has a visible light transmittance ≥80% and an infrared transmission loss of less than 5%. In terms of circuit management design, a spiral copper tube runs through the cavity sidewalls, with the outer wall of the tube wrapped in a rubber buffer layer, and the interior filled with a nano-sound-absorbing material with a porosity of 95%.

[0091] Example 2

[0092] The passive noise reduction protective cover 100 provided in Example 2 differs from that in Example 1 in that the light-transmitting observation window 2 adopts a composite structure of ZnS (thickness 5mm) and sapphire glass (thickness 3mm), with argon gas filling the interlayer. The temperature control compensation module 14 adds a circulating water channel (flow rate 0.5L / min), forming an active heat dissipation system with the semiconductor cooling chip.

[0093] The passive noise reduction protective cover 100 of this invention can effectively reduce noise and protect the atomic force microscope, thereby improving the measurement accuracy of the atomic force microscope.

[0094] Figure 8 This is a comparison chart showing the noise level in decibels with and without the passive noise reduction protective cover 100 of this invention. Figure 9 An exemplary atomic-precision image obtained by atomic force microscopy is shown when using the passive noise-reducing protective cover 100 of this invention.

[0095] Depend on Figure 8 As can be seen, when using the passive noise reduction protective cover 100 of this utility model, the decibel level at the 1kHz characteristic frequency is only 36.8±1dB, effectively reducing noise by 20%.

[0096] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the present invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0097] Therefore, those skilled in the art should recognize that although many exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications conforming to the principles of the present invention can be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and recognized as covering all such other variations or modifications.

Claims

1. A passive noise-reducing protective cover for an atomic force microscope, the atomic force microscope comprising an atomic force microscope body and a shock-absorbing support system located on a support surface for supporting the atomic force microscope body, characterized in that, The passive noise reduction protective cover includes a soundproof shell with an open bottom, such that when in use, the soundproof shell covers the support surface through the bottom of the opening to form a sealed cavity inside the soundproof shell, so as to accommodate the atomic force microscope body and the shock absorption support system in a manner that does not contact or fix them to any part of the protective cover.

2. The passive noise reduction protective cover according to claim 1, characterized in that, The soundproof enclosure includes a frame and soundproof panels that are fixed to the frame to form the front, side and top panels of the soundproof enclosure. Each of the aforementioned sound insulation panels includes: The outer structural layer is fixed to the frame; A composite broadband sound-absorbing layer is bonded to the inner surface of the outer structural layer; and A density gradient sound insulation layer is attached to the inner surface of the composite broadband sound absorption layer.

3. The passive noise reduction protective cover according to claim 2, characterized in that, The composite broadband sound-absorbing layer comprises a lead rubber damping layer and an alumina ceramic plate bonded together.

4. The passive noise reduction protective cover according to claim 2, characterized in that, The front of the soundproof enclosure includes an upper double door and a lower double door, which are used to independently open the upper and lower parts of the sealed cavity, respectively.

5. The passive noise reduction protective cover according to claim 4, characterized in that, Each of the upper double door and the lower double door includes two doors that are respectively hinged to the frame of the soundproof enclosure; The passive noise reduction protective cover also includes an opening and closing mechanism corresponding to each of the doors. Each opening and closing mechanism includes a pivot fixed to the frame and a pneumatic support rod with one end connected to the pivot and the other end connected to the door, so that each door can be opened independently and controllably through the pneumatic support rod.

6. The passive noise reduction protective cover according to claim 5, characterized in that, Each of the doors has a sealing strip embedded in its frame, and a wedge-shaped guide structure is provided on the closed contact surface of the two doors.

7. The passive noise reduction protective cover according to claim 4, characterized in that, The upper double door and / or the lower double door are provided with light-transmitting observation windows; The light-transmitting observation window is formed by a zinc sulfide crystal plate, or by a composite of a zinc sulfide crystal plate and a transparent substrate, and has broadband transmission performance in the visible and infrared bands.

8. The passive noise reduction protective cover according to claim 2, characterized in that, Also includes: The temperature control compensation module is located in the sealed cavity and embedded in the density gradient sound insulation layer.

9. The passive noise reduction protective cover according to claim 8, characterized in that, The temperature control compensation module includes a semiconductor cooling chip and a temperature distribution plate, used to uniformize and compensate the temperature within the sealed cavity; and / or The temperature control compensation module includes a circulating cooling channel, which is disposed in the sealed cavity, and the outlet and inlet of the circulating cooling channel extend out of the soundproof cover to be connected to the cooling fluid source for active heat dissipation.

10. The passive noise reduction protective cover according to claim 2, characterized in that, Also includes: A spiral wiring channel running through the soundproof enclosure; The spiral wiring channel includes a spiral metal tube, a buffer layer wrapped around the outside of the spiral metal tube, and a high-porosity sound-absorbing material filled inside the spiral metal tube.

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