High frame rate filter switching mechanism under cold optics

Abstract

The present disclosure provides a high-frame-rate filter switching mechanism under cold optics, comprising: a Dewar box composed of multiple Dewar walls, the temperature inside the Dewar box is lower than minus 200 degrees, and the vacuum degree is lower than 10 ‑5 pa, the surface of at least one of the Dewar walls is provided with a first through hole; a filter wheel is arranged in a low-temperature environment in the Dewar box, the filter wheel is provided with multiple fan ring arranged filters, the filters are configured to realize high-frame-rate filtering in a low-temperature environment, and the switching frequency of the multiple filters is greater than 100Hz; a servo motor is arranged in a normal-temperature environment outside the Dewar box and is configured to drive the filter wheel to rotate; a transmission mechanism connects the servo motor and the filter wheel through the first through hole and is configured to provide transmission power while reducing heat conduction from the servo motor to the filter wheel.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of optical instruments, in particular to a high-frame-rate filter switching mechanism under cold optics. BACKGROUND

[0002] Cold optics refers to an optical system working in a low-temperature environment. Generally, an optical system works at room temperature, but in some special application scenarios, such as deep space exploration and low-temperature physical experiments, the working temperature of the optical system needs to be reduced to a level much lower than room temperature, even to liquid nitrogen temperature (-200℃) or lower. In the application of infrared multispectral imaging, in order to reduce the influence of thermal radiation and stray light of optical mechanical structures in the optical path, cold optical technology is needed to suppress the thermal radiation and stray light in the optical path, so as to effectively reduce the background photon flux and play the role of the background limited detector, thereby improving the sensitivity of the detector. As an optical element for selectively transmitting or blocking light in a specific wavelength range, the filter is an indispensable component of an infrared multispectral imaging optical system, and the filter is usually located at the end of the optical path, and its own thermal radiation directly affects the signal-to-noise ratio of infrared optical imaging, especially for long-wave infrared imaging systems, so the temperature of the filter needs to be reduced to low temperature (-200℃). For a high-frame-rate multispectral infrared imaging system under cold optics, the traditional driving mode of a circular filter plus a stepper motor is difficult to realize high-frame-rate switching of the filter, and it is difficult to realize two-grade rapid and stable switching of the filter under 50Hz (0.02s); it is also difficult to realize the movement of the filter switching movement mechanism under low temperature. SUMMARY

[0003] The present disclosure aims to provide a high-frame-rate filter switching mechanism under cold optics to solve the technical problems in the related art. The specific scheme is as follows:

[0004] The present disclosure provides a high-frame-rate filter switching mechanism under cold optics, which comprises: a Dewar box composed of a plurality of Dewar walls, the temperature inside the Dewar box is lower than -200 degrees Celsius, the vacuum degree is lower than 10 -5 pa, a first through hole is provided through the surface of at least one of the Dewar walls; a filter wheel is arranged in the low-temperature environment in the Dewar box, a plurality of fan ring-shaped filters are arranged on the filter wheel, the filters are configured to realize high-frame-rate filtering in a low-temperature environment, and the switching frequency of the plurality of filters is greater than 100Hz; a servo motor is arranged in the normal-temperature environment outside the Dewar box and is configured to drive the filter wheel to rotate; a transmission mechanism is connected between the servo motor and the filter wheel through the first through hole and is configured to provide transmission power while reducing heat conduction from the servo motor to the filter wheel.

[0005] In some embodiments, the transmission mechanism comprises a sealing transmission member extending at least partially into the first through hole and configured to seal the first through hole while providing transmission power.

[0006] In some embodiments, the sealing transmission member comprises a sealing transmission member body and a connecting portion rotationally connected to the sealing transmission member body and configured to be fixedly connected to the Dewar wall to seal the first through hole.

[0007] In some embodiments, the sealing transmission member further comprises a transmission shaft penetrating through the sealing transmission member body, a first end of the transmission shaft being connected to the servo motor, and a second end of the transmission shaft being connected to the filter wheel, wherein the sealing transmission member body is provided with a nano-magnetic liquid to prevent air from entering the Dewar box.

[0008] In some embodiments, the transmission mechanism further comprises a heat insulation pad sleeved on the transmission shaft or a filter wheel adapter of the filter wheel and configured to block heat conduction between the transmission mechanism and the filter wheel.

[0009] In some embodiments, the heat insulation pad is provided with through holes on the surface and configured to increase the thermal resistance of the heat insulation pad, the through holes comprising first through holes extending along the axial direction of the heat insulation pad and penetrating through the heat insulation pad, and second through holes extending along the radial direction of the heat insulation pad and penetrating through the heat insulation pad.

[0010] In some embodiments, the high-frame-rate filter switching mechanism under the cold optics further comprises a low-temperature cold plate provided in the Dewar box and configured to support the filter wheel and cool the filter wheel.

[0011] In some embodiments, the low-temperature cold plate comprises a cooling portion provided in the low-temperature cold plate and configured to cool the filter.

[0012] In some embodiments, the cooling portion comprises a second through hole penetrating through the low-temperature cold plate and configured to accommodate the filter, and / or a receiving groove mounted at the bottom of the second through hole and configured to accommodate the filter, wherein a plurality of filters pass through the second through hole and / or the receiving groove in turn in response to rotation of the filter wheel.

[0013] In some embodiments, the transmission mechanism further comprises a double diaphragm coupling connecting the sealing transmission member and the filter wheel and configured to adjust axial offset of the filter wheel caused by a low-temperature environment.

[0014] Compared with the related art, the above scheme of the embodiments of the present disclosure has at least the following beneficial effects:

[0015] The high-frame-rate filter switching mechanism under cold optics provided by the present disclosure is characterized in that the filter is in a low-temperature environment, while the servo motor is in a room-temperature environment. The transmission mechanism can realize torque transmission from room temperature and normal pressure to low temperature and vacuum, and can efficiently and stably transmit the power of the servo motor to the filter wheel, so as to ensure that the filter wheel can rotate accurately and quickly in a low-temperature vacuum environment. The servo motor is installed in the room-temperature environment outside the Dewar box, thereby avoiding the influence of vacuum and low temperature on the performance of the motor, prolonging the service life of the motor, reducing the maintenance cost, and improving the stability and reliability of the system.

[0016] It should be understood that the foregoing general description and the following detailed description are only exemplary and explanatory, and are not limiting to the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0017] The drawings incorporated into the specification and forming a part of the specification, show embodiments consistent with the present disclosure, and together with the specification, serve to explain the principles of the present disclosure. It is clear that the drawings in the following description are only some embodiments of the present disclosure, and other drawings can be obtained from these drawings without creative labor for those skilled in the art. In the drawings:

[0018] Figure 1 A structural schematic diagram of a high-frame-rate filter switching mechanism under cold optics according to an exemplary embodiment.

[0019] Figure 2 A sectional view of a high-frame-rate filter switching mechanism under cold optics according to an exemplary embodiment.

[0020] Figure 3 A structural schematic diagram of a low-temperature cold plate according to an exemplary embodiment.

[0021] Figure 4 A structural schematic diagram of another low-temperature cold plate according to an exemplary embodiment.

[0022] Figure 5 A schematic diagram of a sealed transmission member according to an exemplary embodiment.

[0023] Figure 6 A structural schematic diagram of a heat insulation pad according to an exemplary embodiment.

[0024] Figure 7 A structural schematic diagram of a filter wheel according to an exemplary embodiment.

[0025] REFERENCE SIGNS:

[0026] Servo motor 100, Dewar wall 200, first through-hole 201, low-temperature cold plate 210, second through-hole 202, accommodating groove 220;

[0027] Filter wheel 300, filter wheel adapter 310, filter 320;

[0028] Transmission mechanism, sealed transmission component 410, first end 411, second end 412, sealed transmission component body 413, connecting part 414, single diaphragm coupling 421, double diaphragm coupling 422;

[0029] Heat insulation pad 500, first through hole 501, second through hole 502. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this disclosure clearer, the disclosure will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0031] The terminology used in the embodiments of this disclosure is for the purpose of describing particular embodiments only and is not intended to limit the disclosure. The singular forms “a,” “the,” and “the” as used in the embodiments of this disclosure and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise; “multiple” generally includes at least two, and other quantifiers are similarly intended.

[0032] It should be understood that although the terms first, second, third, etc., may be used to describe embodiments of this disclosure, these descriptions should not be limited to these terms. These terms are only used to distinguish the described objects. For example, first may also be referred to as second without departing from the scope of embodiments of this disclosure, and similarly, second may also be referred to as first. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0033] It should be understood that the term "and / or" as used herein is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship. The singular forms "a," "the," and "the" are also intended to include the plural forms unless the context clearly indicates otherwise.

[0034] It is further understood that the terms “center,” “longitudinal,” “lateral,” “front,” “rear,” “up,” “down,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” and “outer,” etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this embodiment and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0035] In the description of this disclosure, it should be noted that, unless otherwise expressly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0036] Depending on the context, the words “if” or “suppose” as used here can be interpreted as “when” or “in response to determination” or “in response to detection.” Similarly, depending on the context, the phrases “if determination” or “if detection (of the stated condition or event)” can be interpreted as “when determination” or “in response to determination” or “when detection (of the stated condition or event)” or “in response to detection (of the stated condition or event).”

[0037] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0038] In related technologies, the drive motor needs to operate in a low-temperature environment along with the filter wheel to achieve filter switching. The drive motor is typically a stepper motor, and since both the stepper motor and filter wheel operate in a low-temperature environment, the requirements for the motor are high, and heat is generated inside the motor, causing thermal pollution. Furthermore, traditional filter wheels mostly use circular filters. However, for high frame rate multispectral infrared imaging systems under cold optics, the traditional circular filter plus stepper motor drive method is difficult to achieve high frame rate switching of the filters, and it is also difficult to achieve the movement of the filter switching motion mechanism at low temperatures.

[0039] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high frame rate filter switching mechanism under cold optics, comprising: a Dewar box composed of multiple Dewar walls, wherein the temperature inside the Dewar box is below -200 degrees Celsius and the vacuum degree is below 10. -5 pa, at least one of the surfaces of the Dewar wall is provided with a first through hole; a filter wheel, disposed in the low-temperature environment inside the Dewar box, the filter wheel is provided with a plurality of fan-shaped filters, the filters are configured to achieve high frame rate filtering in the low-temperature environment, and the switching frequency of the plurality of filters is greater than 100Hz; a servo motor, disposed in the normal temperature environment outside the Dewar box, configured to drive the filter wheel to rotate; a transmission mechanism, passing through the first through hole to connect the servo motor and the filter wheel, configured to provide transmission power while reducing heat conduction from the servo motor to the filter wheel.

[0040] In the high frame rate filter switching mechanism under cold optics provided in this disclosure, the filter is in a low temperature environment, while the servo motor is in a normal temperature environment. The torque can be transmitted from normal temperature and pressure to low temperature vacuum through the transmission mechanism. This can efficiently and stably transmit the power of the servo motor to the filter wheel, ensuring that the filter wheel can rotate accurately and quickly in a low temperature vacuum environment while avoiding the impact of low temperature on motor performance, extending the service life of the motor, reducing maintenance costs, and improving the stability and reliability of the system.

[0041] The optional embodiments of this disclosure are described in detail below with reference to the accompanying drawings.

[0042] This application provides a high frame rate filter switching mechanism under cold optics, including a servo motor 100, a filter wheel 300, a Dewar box, and a transmission mechanism.

[0043] The Dewar box is a low-temperature vacuum chamber with an internal low-temperature vacuum environment. The lowest temperature inside the Dewar box is below -200 degrees Celsius, making it more suitable for filtering light under cold light. The outside of the Dewar box is at room temperature; therefore, the maximum temperature difference between the inside and outside of the Dewar box can reach over 200 degrees Celsius.

[0044] The Dewar box is composed of multiple Dewar walls 200, which can be single-layer or multi-layer structures. The heat insulation effect of a double-layer Dewar wall 200 is better than that of a single-layer Dewar wall 200, but this disclosure does not make specific restrictions on this. Whether the Dewar wall 200 is a single-layer wall or a double-layer wall, it has no substantial impact on the high frame rate filter switching mechanism provided by this disclosure.

[0045] In some embodiments, the filter wheel 300 is installed inside a Dewar box and configured to equip filters 320 with different wavelength transmittances. By rotating the filter wheel 300, different filters are switched to obtain spectral information of the target light source in different wavelength bands. Low-temperature environments can make the optical characteristics of the filter wheel 300 more stable and reduce filtering thermal interference. Specifically, the filter wheel 300 includes a filter wheel adapter 310 and filters 320. Multiple filters 320 are mounted on the filter wheel 300. The filters 320 are multiple fan-shaped ring-arranged filters, and the switching frequency of the multiple filters is greater than 100Hz, configured to achieve high frame rate filtering in low-temperature environments. The filter wheel adapter 310 is connected to a transmission mechanism, configured to allow the filter wheel 300 to be connected to a drive device to obtain driving force. The drive device can be a servo motor 100.

[0046] The servo motor 100 is in a normal temperature environment and is equipped with an absolute encoder. It is configured to drive the filter wheel 300 to rotate, providing power and position feedback for the movement of the filter wheel 300, thereby realizing high frame rate and frequency conversion switching of the filter 320 and position feedback of the filter 320.

[0047] In some embodiments, the Dewar box is further provided with a refrigeration device configured to maintain the interior of the Dewar box at -200°C and 10°C. -5 In the low-temperature vacuum environment of Pa, the transmission mechanism passes through the Dewar wall 200 and is connected to the servo motor 100 and the filter wheel 300 respectively, and is configured so that the servo motor 100 at room temperature can drive the filter wheel 300 in the low-temperature environment through the transmission mechanism.

[0048] In some embodiments, the transmission mechanism includes a sealed transmission member 410, a portion of which penetrates the Dewar wall 200 of the Dewar box and is configured to prevent outside air from entering the Dewar box, thereby enabling torque transmission of the servo motor 100 from room temperature to low-temperature vacuum.

[0049] like Figure 2 As shown, a first through hole 201 is provided through the thickness direction of the Dewar wall 200. A part of the sealing transmission member 410 passes through the first through hole 201 and is connected to the filter wheel 300, thereby enabling the servo motor 100 to drive the filter wheel 300 to rotate.

[0050] Specifically, the sealing transmission component 410 includes: a sealing transmission component body 413, a connecting portion 414, and a transmission shaft.

[0051] The connecting part 414 is disposed on the outside of the sealing transmission component body 413 and configured to be sealed to the Dewar wall 200, so that the sealing transmission component 410 blocks the first through hole 201 and prevents external air from entering the Dewar box. The connecting part 414 and the first through hole 201 can be metal-sealed. Extremely low surface roughness can be achieved through precision machining, so that the connecting part 414 fits tightly with the Dewar wall 200 around the first through hole 201. The metal seal can effectively block fluid leakage and maintain a good sealing effect under harsh conditions such as high temperature and high pressure. Since the outside of the Dewar box is at room temperature, and the external room temperature environment may affect the temperature of the filter wheel 300, the transmission mechanism uses the sealing transmission component 410 to seal the first through hole 201 of the Dewar box when passing through the first through hole 201, which can prevent fluid from entering the Dewar box and avoid disrupting the vacuum environment inside the Dewar box.

[0052] The drive shaft is disposed through the sealed transmission component body 413. The two ends of the drive shaft are respectively a first end 411 and a second end 412, and the first end 411 and the second end 412 are respectively connected to the servo motor 100 and the filter wheel 300.

[0053] In some embodiments, the transmission mechanism includes a single diaphragm coupling that connects the servo motor 100 and the first end 411, enabling the servo motor 100 to provide driving force at room temperature. The single diaphragm coupling 421 has a simple structure and can compensate for the relative displacement of the two shafts through axial compression.

[0054] In some embodiments, the transmission mechanism further includes a double diaphragm coupling, which connects the second end 412 of the sealed transmission member 410 to the filter wheel adapter 310. This coupling is configured to adjust the axial displacement of the filter wheel 300 caused by the low-temperature environment, stabilizing the rotation center of the filter wheel 300 and preventing filter deviation due to axial displacement from preventing light filtering. The second end 412 is located in the low-temperature vacuum environment inside the Dewar box and is connected to the filter wheel adapter 310 via the double diaphragm coupling 422. The double diaphragm coupling 422 can bend in different directions simultaneously, compensating for the relative displacement of the two shafts through axial compression and lateral tension, and also compensating for shaft torsional deformation. When the temperature inside the Dewar box decreases, the axial connection between the filter wheel adapter 310 and the sealed transmission member 410 may deviate by approximately 5mm. This deviation may interfere with the servo motor 100's drive of the filter wheel 300, causing problems such as eccentric rotation of the filter wheel 300 or vibration of the filter 320. The use of a double diaphragm coupling 422 can effectively compensate for shaft misalignment caused by low temperature, and the double diaphragm coupling 422 can withstand higher loads and has the advantage of stable operation in high-speed and high-power environments.

[0055] In some embodiments, a nano-magnetic liquid is disposed between the drive shaft and the sealing drive body 413. In response to the rotation of the drive shaft, the nano-magnetic liquid will generate an axial magnetic seal to prevent air from entering the Dewar box. At the same time, the nano-magnetic liquid will also absorb some of the heat from the servo motor through the drive shaft. Thus, the sealing drive can not only ensure sealed transmission, but also hinder heat conduction to a certain extent, preventing the heat generated inside the servo motor 100 from entering the Dewar box and causing thermal pollution.

[0056] In some embodiments, since the temperature difference between the inside and outside of the Dewar box is large, and the heat generated by the servo motor 100 during operation may enter the Dewar box through the transmission mechanism, the transmission mechanism also includes a heat insulation pad 500. The heat insulation pad 500 can be a ring-shaped structure, which can be sleeved on the transmission mechanism or the filter wheel adapter 310, configured to reduce the heat loss of the filter wheel 300.

[0057] In some embodiments, in order for the heat insulation pad 500 to effectively insulate against cold, the thickness of the heat insulation pad 500 is not less than 3mm. If the thickness of the heat insulation is less than 3mm, external heat will be easily transferred to the inside of the Dewar box or the inside of the filter wheel 300, affecting the normal operation of the filter wheel 300.

[0058] In some embodiments, the surface of the heat insulation pad 500 is provided with through holes to increase the thermal resistance of the heat insulation pad 500. Multiple through holes may be provided, including a first through hole 501 and a second through hole 502. The first through hole 501 extends axially along the heat insulation pad 500 and penetrates the heat insulation pad 500, and the second through hole 502 extends radially along the heat insulation pad 500 and penetrates the heat insulation pad 500. The through holes effectively increase the heat transfer path, thereby increasing the thermal resistance of the heat insulation pad 500 and effectively reducing the heat loss of the filter wheel 300.

[0059] In some embodiments, the heat insulation pad 500 is made of a polymer material, such as polyimide. Polyimide has outstanding high-temperature resistance, excellent mechanical properties, and high tensile strength. In addition, polyimide has excellent insulation properties, which can effectively prevent leakage and electrical faults in high-frequency and high-voltage environments.

[0060] In some embodiments, the filter switching mechanism further includes a low-temperature cooling plate 210, which is disposed inside the Dewar box and fixedly connected to the inner wall of the Dewar wall 200. The plate is configured to support the filter wheel 300 and cool it. The mounting base of the filter wheel 300 is fixed to the low-temperature cooling plate 210. The filter wheel 300 also includes a low-temperature bearing. The filter wheel 300 is mounted on the mounting base via an inner and outer ring pressure plate. The filter 320 is fixedly mounted to the filter holder of the filter wheel 300 via a pressure plate.

[0061] In some embodiments, the low-temperature cold plate includes a cooling section, the cooling section being provided with the low-temperature cold plate 210, configured to cool the filter 320. For example... Figure 2 , Figure 3 As shown, the cooling section includes a second through hole 202 and a receiving groove 220 that are provided through the thickness direction of the low-temperature cold plate 210. The second through hole 202 is adapted to accommodate at least a portion of the filter wheel 300 and to cool the filter wheel 300. The receiving groove 220 is installed at the bottom of the second through hole 202 and communicates with the second through hole. The receiving groove 220 and the second through hole together form a receiving space suitable for accommodating the filter 320. The receiving space is sufficient to accommodate any one filter 320. In response to the rotation of the filter wheel 300, multiple filters 320 pass through the receiving space in sequence to achieve the cooling of the filter 320 by the low-temperature cold plate 210, so that the filter 320 can be better applied to cold light filtering.

[0062] Specifically, such as Figure 3 As shown, the height of the filter 320 inside the cooling section is H1, and the height of the internal space of the cooling section is H2, where H2 > H1, so that when the filter wheel 300 rotates, the filter 320 can be completely inside the cooling section, thereby achieving rapid cooling of the filter 320.

[0063] In some embodiments, the cooling section includes a second through hole 202 or a receiving groove 220.

[0064] like Figure 4 As shown, when the second through-hole 202 is provided alone on the low-temperature cold plate 210, the second through-hole 202 extends through the low-temperature cold plate. The thickness of the second through-hole 202 should be greater than or equal to the axial width of the filter 320. Thus, the cooling section only needs the structure of the second through-hole 202 to accommodate the filter 320 and cool it down. In response to the rotation of the filter wheel 300, the filters 320 pass through the second through-hole 202 one by one to achieve individual cooling of the filters 320.

[0065] In some embodiments, when the receiving groove 220 is disposed separately on the low-temperature cold plate 210, the receiving groove 220 is disposed on the low-temperature cold plate 210 for accommodating the filter 320. The groove of the receiving groove 220 has a certain depth, so that the receiving space of the receiving groove 220 is sufficient to accommodate the filter 320, thereby cooling the filter 320.

[0066] In some embodiments, the filter 320 is switched in 7 stops to ensure the continuity of the light beam passing through the filter 320 during high-speed rotation of the camera exposure process. In cold optics observation, the filter 320 can be switched according to the actual environment at different times, locations, or under different conditions to adjust the observation strategy, reduce the influence of environmental factors, and ensure the observation effect. The filter 320 can be an arc-shaped filter, and the extension direction of the arc-shaped filter is arc-shaped. When the filter wheel rotates, the projection of the camera sensor in the thickness direction of the filter wheel covers the filter.

[0067] In response to the rotation of the filter wheel 300, the filter 320 can pass sequentially through the second through hole 202 and the receiving groove 220, enabling the low-temperature cold plate 210 to directly cool the filter 320, such as... Figure 2 , Figure 7 As shown, during the rotation of the filter wheel 300, the filter 320 passes through the second through hole 202 in sequence to achieve the cooling of the filter 320 by the low temperature cold plate 210, reduce the influence of thermal radiation on infrared spectral imaging when the filter 320 is switched, and further ensure that the cooled filter 320 can align the corresponding partition coating with the light-transmitting aperture, thereby achieving high frame rate filtering under cold optics.

[0068] like Figure 7 As shown, taking the switching frequency of the filter wheel 300 as 100Hz as an example, the filter wheel 300 rotates at a constant speed during operation, with a rotation speed of 100×60 / 7=857r / min. The switching between the two filter 320 requires the filter wheel 300 to rotate by an angle of θ1+θ2. Within the angle range of θ1, the filter 320 is in a fully open state, and within the angle range of θ2, the filter 320 is in a non-fully open state with light passing through and being partially blocked. During operation, the camera sampling time corresponding to the switching frequency of 100Hz is 10ms, and the camera exposure time in each sampling cycle is θ1 / (θ1+θ2)×10ms. In this way, the high frame rate switching of the filter 320 can be achieved through the fan-shaped structure of the filter, the constant speed rotation of the filter wheel 300, and the precise position control of the servo motor 100.

[0069] In some embodiments, to achieve high frame rate filter switching under cold optics, the following key steps are required: Cooling system: The filter wheel 300 is cooled using a Dewar box. A vacuum environment is maintained inside the Dewar box, and its internal cryogenic cold plate 210 can be kept at -200°C. The filter wheel 300 is directly mounted on the cryogenic cold plate 210, which is cooled by a cooling system. Furthermore, the filter wheel 300 cools the filter 320 during rotation, thereby reducing the impact of thermal radiation on infrared spectral imaging during filter 320 switching.

[0070] A servo motor 100 is selected to achieve high frame rate switching of the filter wheel 300 via direct drive. The servo motor 100 provides both high speed and power, and accurately reflects the position of the filter 320. Since the servo motor 100 operates at room temperature, a transmission mechanism is used to mount it at room temperature outside the Dewar box. This improves the working efficiency and lifespan of the servo motor 100 and avoids thermal contamination affecting the normal operation of the filter wheel 300 or the Dewar box. The transmission mechanism needs to pass through the Dewar box to transfer torque from room temperature and pressure to low-temperature vacuum. This process can be achieved through a sealed transmission component 410. Simultaneously, a polyimide thermal insulation pad 500 with good thermal insulation performance and a special porous structure is used for insulation, maximizing thermal resistance without reducing structural rigidity.

[0071] The specific structure, working principle, and beneficial effects of the high frame rate filter switching mechanism under cold optics provided in this disclosure can be found in any of the above embodiments, and will not be elaborated upon here.

[0072] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems or apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple, and relevant parts can be referred to the method section.

[0073] The above embodiments are only used to illustrate the technical solutions of this disclosure, and are not intended to limit it. Although this disclosure 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 of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this disclosure.

Claims

1. A high frame rate filter switching mechanism under cold optics, characterized in that, include: A Dewar box, composed of multiple Dewar walls, has an internal temperature below -200 degrees Celsius and a vacuum level below 10. -5 pa, at least one of the surfaces of the Dewar wall is provided with a first through hole; A filter wheel is set in a low-temperature environment inside the Dewar box. The filter wheel is provided with multiple filters arranged in a fan-shaped ring. The filters are configured to achieve high frame rate filtering in a low-temperature environment. The switching frequency of the multiple filters is greater than 100Hz. A servo motor, located in a normal temperature environment outside the Dewar box, is configured to drive the filter wheel to rotate; A transmission mechanism, passing through the first through hole and connecting the servo motor and the filter wheel, is configured to provide power transmission while reducing heat conduction from the servo motor to the filter wheel. The transmission mechanism includes a sealing transmission member, at least partially extending into the first through hole, configured to seal the first through hole while providing power transmission. The sealing transmission member includes: Sealed transmission component body; The connecting part is rotatably connected to the sealing transmission component body and is configured to be fixedly connected to the Dewar wall to seal the first through hole; A drive shaft extends through the sealed transmission component body; the first end of the drive shaft is connected to the servo motor, and the second end of the drive shaft is connected to the filter wheel. The sealed transmission component contains a nano-magnetic liquid, configured to prevent air from entering the Dewar box.

2. The high frame rate filter switching mechanism under cold optics according to claim 1, characterized in that, The transmission mechanism also includes: A heat insulation pad is fitted onto the drive shaft or the filter wheel adapter of the filter wheel, and is configured to block heat conduction between the drive mechanism and the filter wheel.

3. The high frame rate filter switching mechanism under cold optics according to claim 2, characterized in that, The heat insulation pad has through holes on its surface, configured to increase the thermal resistance of the heat insulation pad. The through holes include: A first through hole extends along the axial direction of the heat insulation pad and penetrates the heat insulation pad; The second through hole extends radially along the insulation pad and penetrates the insulation pad.

4. The high frame rate filter switching mechanism under cold optics according to claim 1, characterized in that, Also includes: A low-temperature cold plate is placed inside the Dewar box and configured to support the filter wheel and cool it.

5. The high frame rate filter switching mechanism under cold optics according to claim 4, characterized in that, The low-temperature cold plate includes: A cooling section is disposed on the low-temperature cold plate and configured to cool the filter.

6. The high frame rate filter switching mechanism under cold optics according to claim 5, characterized in that, The cooling unit includes: A second through-hole is provided through the low-temperature cold plate to accommodate the filter; and / or A receiving groove, installed at the bottom of the second through hole, is used to accommodate the filter. In response to the rotation of the filter wheel, the plurality of filters pass sequentially through the second through hole and / or the receiving groove.

7. The high frame rate filter switching mechanism under cold optics according to claim 1, characterized in that, The transmission mechanism also includes: A double diaphragm coupling connects the sealed transmission component to the filter wheel, and is configured to adjust the axial offset of the filter wheel caused by low temperature environment.

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