High-frame-frequency optical filter switching mechanism under cold optics

Abstract

The invention provides a high-frame-frequency optical filter switching mechanism under cold optics, and the mechanism comprises a Dewar box which is composed of a plurality of Dewar walls, the temperature in the Dewar box is lower than-200 DEG C, the vacuum degree in the Dewar box is lower than 10 <-5 > pa, and a first through hole is formed in the surface of at least one Dewar wall in a penetrating manner; the filter wheel is arranged in a low-temperature environment in the Dewar box, the filter wheel is provided with a plurality of optical filters which are arranged in a sector ring shape, the optical filters are configured to realize high-frame-frequency light filtering in the low-temperature environment, and the switching frequency of the optical filters is greater than 100Hz; the servo motor is arranged in a normal-temperature environment outside the Dewar box and is configured to drive the filter wheel to rotate; and the transmission mechanism penetrates through the first through hole, is connected with the servo motor and the filter wheel, and is configured to provide transmission force and reduce heat conduction from the servo motor to the filter wheel at the same time.

Description

Technical Field

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

[0002] Cold optics refers to optical systems that work in low-temperature environments. Normally, optical systems work at room temperature, but in some special application scenarios, such as deep space exploration and low-temperature physics experiments, the operating temperature of the optical system needs to be reduced to a level far below room temperature, even to liquid nitrogen temperature (-200°C) or lower. In infrared multispectral imaging applications, in order to reduce the influence of thermal radiation and stray light of the optomechanical structure in the optical path, cold optical technology is needed to suppress the thermal radiation and stray light of the optical path, so as to effectively reduce the background photon flux and play the role of background limit detector, thereby improving the sensitivity of the detector. As an optical element used to selectively transmit or block light within a specific wavelength range, the filter is an indispensable component of the infrared multispectral imaging optical system. At the same time, 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 the long-wave infrared imaging system, so the filter temperature needs to be reduced to a low temperature (-200°C). For high frame rate multi-spectral infrared imaging systems under cold optics, the traditional circular filter plus stepper motor drive method is difficult to achieve high frame rate switching of filters. It is difficult to achieve two-speed fast and stable switching of filters at 50Hz (0.02s); it is also difficult to achieve the movement of the filter switching motion mechanism at low temperatures. Summary of the invention

[0003] The purpose of the present disclosure is 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 embodiment of the present disclosure provides a high frame rate filter switching mechanism under cold optics, including: a high frame rate filter switching mechanism under cold optics, including: a dewar box, composed of a plurality of dewar walls, the temperature in the dewar box is lower than minus 200 degrees, the vacuum degree is lower than 10 -5 pa, a first through hole is penetrated on the surface of at least one of the Dewar walls; a filter wheel is arranged in the low-temperature environment in the Dewar box, and a plurality of filters arranged in a fan ring are arranged on the filter wheel, and the filters are configured to achieve 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 a normal temperature environment outside the Dewar box, and is configured to drive the filter wheel to rotate; a transmission mechanism penetrates the first through hole to connect the servo motor and the filter wheel, and is configured to provide transmission force while reducing heat conduction from the servo motor to the filter wheel.

[0005] In some embodiments, the transmission mechanism includes: a sealing transmission member, which at least partially extends into the first through hole and is configured to seal the first through hole while providing transmission force.

[0006] In some embodiments, the sealing transmission member includes: a sealing transmission member body; and a connecting portion, rotatably 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 sealed transmission component further includes: a transmission shaft, which passes through the sealed transmission component body, wherein the first end of the transmission shaft is connected to the servo motor, and the second end of the transmission shaft is connected to the filter wheel, wherein nano-magnetic liquid is disposed in the sealed transmission component body and is configured to prevent air from entering the Dewar box.

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

[0009] In some embodiments, the surface of the thermal insulation pad is provided with through holes, which are configured to increase the thermal resistance of the thermal insulation pad, and the through holes include: a first through hole, which extends along the axial direction of the thermal insulation pad and penetrates the thermal insulation pad; a second through hole, which extends along the radial direction of the thermal insulation pad and penetrates the thermal insulation pad.

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

[0011] In some embodiments, the cryogenic cold plate includes: a cooling portion, disposed on the cryogenic cold plate, configured to cool the filter.

[0012] In some embodiments, the cooling part includes: a second through hole, which is arranged through the low-temperature cold plate, for accommodating the filter; and / or a receiving groove, which is installed at the bottom of the second through hole, for accommodating the filter, wherein, in response to the rotation of the filter wheel, a plurality of the filters pass through the second through hole and / or the receiving groove in sequence.

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

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

[0015] In the high frame rate filter switching mechanism under cold optics provided by the present disclosure, the filter is in a low temperature environment, while the servo motor is in a normal temperature environment. The transmission mechanism can realize the transmission of torque from normal temperature and pressure to low temperature vacuum, and the power of the servo motor can be efficiently and stably transmitted to the filter wheel, ensuring that the filter wheel can rotate accurately and quickly in a low temperature vacuum environment. The servo motor is installed in a room temperature environment outside the Dewar box, which avoids the influence of vacuum and low temperature on the motor performance, prolongs the service life of the motor, reduces maintenance costs, and improves the stability and reliability of the system.

[0016] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the present disclosure, and together with the specification, are used to explain the principles of the present disclosure. Obviously, the drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

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

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

[0020] Figure 3 A schematic structural diagram of a cryogenic cold plate is shown according to an exemplary embodiment.

[0021] Figure 4 A schematic structural diagram of another cryogenic cold plate is shown according to an exemplary embodiment.

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

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

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

[0025] Reference numerals:

[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 member 410, first end 411, second end 412, sealed transmission member body 413, connecting portion 414, single diaphragm coupling 421, double diaphragm coupling 422;

[0029] Thermal insulation pad 500 , first through hole 501 , and second through hole 502 . DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present disclosure clearer, the present disclosure will be further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0031] The terms used in the embodiments of the present disclosure are only for the purpose of describing specific embodiments, and are not intended to limit the present disclosure. The singular forms "a", "said" and "the" used in the embodiments of the present disclosure and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings, and "multiple" generally includes at least two, and other quantifiers are similar.

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

[0033] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship. The singular forms "a", "the" and "the" are also intended to include the plural forms, unless the context clearly indicates other meanings.

[0034] It should be further understood that the terms "center", "longitudinal", "lateral", "front", "back", "up", "down", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present embodiment and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0035] In the description of the present disclosure, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] As used herein, the words "if" and "if" may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0037] It should also be noted that the term "includes", "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, so that a commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprising a ..." do not exclude the existence of other identical elements in the commodity or device including the elements.

[0038] In the related art, the driving motor needs to work in a low-temperature environment with the filter wheel to achieve the switching of the filter. The driving motor generally adopts a stepper motor, and the stepper motor and the filter wheel are in a low-temperature environment. Low-temperature operation has high requirements for the motor, and heat will be generated inside the motor, causing the problem of thermal pollution. In addition, most traditional filter wheels use circular filters. However, for high-frame-rate multi-spectral infrared imaging systems under cold optics, the traditional circular filter plus stepper motor drive method is difficult to achieve high-frame-rate switching of filters, and it is also difficult to achieve the movement of the filter switching motion mechanism at low temperatures.

[0039] The purpose of the present 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, which is composed of a plurality of Dewar walls, wherein the temperature in the Dewar box is lower than minus 200 degrees and the vacuum degree is lower than 10 -5 pa, a first through hole is penetrated on the surface of at least one of the Dewar walls; a filter wheel is arranged in the low-temperature environment in the Dewar box, and a plurality of filters arranged in a fan ring are arranged on the filter wheel, and the filters are configured to achieve 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 a normal temperature environment outside the Dewar box, and is configured to drive the filter wheel to rotate; a transmission mechanism penetrates the first through hole to connect the servo motor and the filter wheel, and is configured to provide transmission force 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 by the present invention, the filter is in a low temperature environment, while the servo motor is in a normal temperature environment. The transmission mechanism can realize the transmission of torque from normal temperature and pressure to low temperature vacuum, and can efficiently and stably transmit the power of the servo motor to the filter wheel, thereby ensuring that the filter wheel can rotate accurately and quickly in a low temperature vacuum environment while avoiding the influence of vacuum and low temperature on the motor performance, thereby extending the service life of the motor, reducing maintenance costs, and improving the stability and reliability of the system.

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

[0042] The present 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 box with a low-temperature vacuum environment inside. The lowest temperature inside the Dewar box is lower than -200 degrees, which is more suitable for filtering under cold light. The outside of the Dewar box is room temperature, so the maximum temperature difference between the inside and outside of the Dewar box can reach more than 200 degrees.

[0044] The Dewar box is composed of a plurality of Dewar walls 200, and the Dewar wall 200 can be a single-layer or multi-layer structure. The heat insulation effect of the double-layer Dewar wall 200 is better than that of the single-layer Dewar wall 200, but the present 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 effect on the high frame rate filter switching mechanism provided by the present disclosure.

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

[0046] The servo motor 100 is in a room temperature environment and is internally provided with an absolute encoder configured to drive the filter wheel 300 to rotate, provide power and position feedback for the movement of the filter wheel 300, and realize high frame rate and variable frequency switching of the filter 320 and position feedback of the filter 320.

[0047] In some embodiments, the dewar box is also provided with a refrigeration device configured to keep the interior of the dewar box at -200°C, 10 -5 The transmission mechanism penetrates the Dewar wall 200 and is respectively connected to the servo motor 100 and the filter wheel 300, 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 passes through the Dewar wall 200 of the Dewar box, configured to prevent external air from entering the Dewar box, thereby realizing 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 in the thickness direction of the Dewar wall 200 , and a portion of the sealing transmission member 410 passes through the first through hole 201 and is connected to the filter wheel 300 , further 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 portion 414 is disposed outside the sealing transmission member body 413 and is configured to be sealed and connected with the Dewar wall 200, so that the sealing transmission member 410 blocks the first through hole 201 to prevent external air from entering the Dewar box. The connecting portion 414 and the first through hole 201 can be metal seals. The extremely low surface roughness can be achieved through precision machining, so that the connecting portion 414 and the Dewar wall 200 around the first through hole 201 are tightly fitted. The metal seal can effectively prevent fluid leakage and maintain a good sealing effect under harsh working conditions such as high temperature and high pressure. Since the outside of the Dewar box is a normal temperature environment, and the external normal temperature environment may affect the temperature of the filter wheel 300, therefore, when the transmission mechanism passes through the first through hole 201, the sealing transmission member 410 is used to seal with the first through hole 201 of the Dewar box, which can prevent the fluid from entering the Dewar box and prevent the vacuum environment in the Dewar box from being destroyed.

[0052] The transmission shaft is disposed through the sealed transmission member body 413 , and the two ends of the transmission 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, which connects the servo motor 100 and the first end 411, so that the servo motor 100 can 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 with the filter wheel adapter 310, and is configured to adjust the axial deviation of the filter wheel 300 caused by the low temperature environment, so that the rotation center of the filter wheel 300 is stable, and avoids the filter deviation from filtering the light due to the axial deviation. 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 through the double diaphragm coupling 422. The double diaphragm coupling 422 can be bent in different directions at the same time, and compensates for the relative displacement of the two axes through axial compression and lateral stretching, and can also compensate for the distortion of the axis. When the temperature inside the Dewar box decreases, the axial connection between the filter wheel adapter 310 and the sealed transmission member 410 may have a deviation of about 5 mm, which may interfere with the driving of the filter wheel 300 by the servo motor 100, causing problems such as eccentric rotation of the filter wheel 300 or vibration of the filter 320. The use of the double diaphragm coupling 422 can effectively compensate for the shaft deviation caused by low temperature, and the double diaphragm coupling 422 can withstand higher loads and has the advantage of stable working state in a high-speed and high-power environment.

[0055] In some embodiments, a nano-magnetic liquid is arranged between the transmission shaft and the sealed transmission member body 413. In response to the rotation of the transmission shaft, the nano-magnetic liquid will generate an axial magnetic seal, which is configured to prevent air from entering the Dewar box. At the same time, the nano-magnetic liquid will also absorb a portion of the heat from the servo motor through the transmission shaft. Therefore, the sealed transmission member can not only ensure sealed transmission, but also, on the other hand, hinder heat conduction to a certain extent, thereby 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 in the working state may enter the Dewar box along with the transmission mechanism, the transmission mechanism further includes a heat insulation pad 500. The heat insulation pad 500 may be an annular structural member, which may be sleeved on the transmission mechanism or the filter wheel adapter 310, and is configured to reduce the loss of coldness of the filter wheel 300.

[0057] In some embodiments, in order for the thermal insulation pad 500 to effectively isolate cold, the thickness of the thermal insulation pad 500 is not less than 3 mm. If the thickness of the thermal insulation is less than 3 mm, the 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 thermal insulation pad 500 is provided with through holes, which are configured to increase the thermal resistance of the thermal insulation pad 500. The through holes may be provided in plurality, including a first through hole 501 and a second through hole 502, wherein the first through hole 501 extends along the axial direction of the thermal insulation pad 500 and penetrates the thermal insulation pad 500, and the second through hole 502 extends along the radial direction of the thermal insulation pad 500 and penetrates the thermal insulation pad 500. The provision of the through holes effectively increases the heat transfer path, thereby increasing the thermal resistance of the thermal insulation pad 500, and can effectively reduce the loss of coldness of the filter wheel 300.

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

[0060] In some embodiments, the filter switching mechanism further includes a cryogenic cold plate 210, which is disposed in the Dewar box and fixedly connected to the inner wall of the Dewar wall 200, and is configured to support the filter wheel 300 and cool the filter wheel 300. The mounting base of the filter wheel 300 is fixed on the cryogenic cold plate 210, and the filter wheel 300 further includes a cryogenic bearing, and the filter wheel 300 is mounted on the mounting base through a bearing inner ring pressure plate and a bearing outer ring pressure plate, and the filter 320 is fixedly mounted on the filter seat of the filter wheel 300 through a pressure plate.

[0061] In some embodiments, the cryogenic cold plate includes a cooling unit, the cooling unit is provided with the cryogenic cold plate 210, and is configured to cool the filter 320. Figure 2 , Figure 3 As shown, the cooling portion includes a second through hole 202 and a receiving groove 220 penetrating in the thickness direction of the low-temperature cold plate 210, the second through hole 202 is suitable for accommodating at least part of the filter wheel 300 and cooling the filter wheel 300; the receiving groove 220 is installed at the bottom of the second through hole 202 and is connected to 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 large enough to accommodate any one filter 320, in response to the rotation of the filter wheel 300, a plurality of the filters 320 pass through the receiving space in sequence to realize 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, if Figure 3 As shown, the height of the filter 320 inside the cooling part is H1, and the height of the internal space of the cooling part is H2, H2>H1, so that when the filter wheel 300 rotates, the filter 320 can be completely inside the cooling part to achieve rapid cooling of the filter 320.

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

[0064] like Figure 4 As shown, when the second through hole 202 is separately provided on the low temperature cold plate 210, the second through hole 202 is provided through the low temperature cold plate, and the thickness of the second through hole 202 should be greater than or equal to the axial width of the optical filter 320. Thus, the cooling part can accommodate the optical filter 320 and cool the optical filter 320 by only using the second through hole 202 structure. In response to the rotation of the filter wheel 300, the optical filters 320 pass through the second through holes 202 one by one to achieve cooling of the optical filters 320 one by one.

[0065] In some embodiments, when the accommodating groove 220 is separately provided on the low temperature cold plate 210, the accommodating groove 220 is provided on the low temperature cold plate 210 to accommodate the optical filter 320. The groove body of the accommodating groove 220 has a certain depth, so that the accommodating space of the accommodating groove 220 is sufficient to accommodate the optical filter 320, so as to cool the optical filter 320.

[0066] In some embodiments, the filter 320 is switched in 7 gears to ensure the continuity of the light beam passing through the filter 320 when the filter 320 is rotated at high speed during camera exposure. In cold optical observation, at different times, places or under different conditions, the filter 320 can be switched according to the actual environment to adjust the observation strategy, reduce the influence of environmental factors, and ensure the observation effect. The filter 320 can be an arc filter, and the extension direction of the arc filter is an arc shape. 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 through the second through hole 202 and the receiving groove 220 in sequence, so that the low temperature cold plate 210 directly cools the filter 320. 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 cooling of the filter 320 by the low-temperature cold plate 210, thereby reducing the influence of thermal radiation on infrared spectrum imaging when the filter 320 is switched, and further ensuring that the cooled filter 320 can align the corresponding partition coating with the light 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 100 Hz as an example, the filter wheel 300 is in a uniform rotation state during operation, and the rotation speed is 100×60 / 7=857 r / min. The switching of the two-speed filter 320 requires the filter wheel 300 to rotate at an angle of θ1+θ2. Within the angle range of θ1, the filter 320 is in a full-pass state, and within the angle range of θ2, the filter 320 is in a non-full-pass state with light blocking. The camera sampling time corresponding to the switching frequency of 100 Hz during operation is 10 ms, and the camera exposure time in each sampling cycle is θ1 / (θ1+θ2)×10 ms. In this way, high frame rate switching of the filter 320 can be achieved through the fan-shaped ring structure of the filter, the uniform rotation of the filter wheel 300 and the precise position control of the servo motor 100.

[0069] In some embodiments, in order to achieve high frame rate filter switching under cold optics, the following key steps need to be taken: Refrigeration system: Use a Dewar box to cool the filter wheel 300. The interior of the Dewar box maintains a vacuum environment, and the cryogenic cold plate 210 inside it can be kept at -200°C. The filter wheel 300 is directly mounted on the cryogenic cold plate 210, and the refrigeration equipment provides cooling for the cryogenic cold plate 210. Furthermore, the filter 320 is cooled during the rotation of the filter wheel 300, thereby reducing the impact of thermal radiation on infrared spectral imaging when the filter 320 is switched.

[0070] The servo motor 100 is selected to realize the high frame rate switching of the filter wheel 300 by direct drive. The servo motor 100 can provide high speed and power, and can accurately feedback the position of the filter 320. Since the servo motor 100 is in a room temperature environment, the transmission mechanism is used to install it in a room temperature environment outside the Dewar box, so as to improve the working efficiency and service life of the servo motor 100 and avoid thermal pollution affecting the normal operation of the filter wheel 300 or the Dewar box. The transmission mechanism needs to pass through the Dewar box to realize the transmission of torque from normal temperature and pressure to low temperature vacuum, which can be achieved by the sealing transmission part 410. At the same time, a polyimide insulation pad 500 with good thermal insulation performance and a special porous structure is used for insulation to increase the thermal resistance as much as possible without reducing the structural rigidity.

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

[0072] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other. For the system or device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description.

[0073] The above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than to limit them. Although the present disclosure has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. A high frame rate filter switching mechanism under cold optics, characterized in that: include: The Dewar box is 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, a first through hole is provided through the surface of at least one of the Dewar walls; A filter wheel is arranged in a low temperature environment in the Dewar box, and a plurality of filters arranged in a fan ring are arranged on the filter wheel, and the filters are configured to achieve high frame rate filtering in a low temperature environment, and the switching frequency of the plurality of filters is greater than 100 Hz; A servo motor is disposed in a room temperature environment outside the Dewar box and is configured to drive the filter wheel to rotate; The transmission mechanism penetrates the first through hole to connect the servo motor and the filter wheel, and is configured to provide transmission force while reducing heat conduction from the servo motor to the filter wheel.

2. The high frame rate filter switching mechanism under cold optics according to claim 1, characterized in that: The transmission mechanism comprises: The sealing transmission member at least partially extends into the first through hole and is configured to seal the first through hole while providing transmission force.

3. The high frame rate filter switching mechanism under cold optics according to claim 2, characterized in that: The sealing transmission member comprises: Sealing transmission body; The connecting portion is rotatably connected to the sealing transmission member body and is configured to be fixedly connected to the Dewar wall to seal the first through hole.

4. The high frame rate filter switching mechanism under cold optics according to claim 3, characterized in that: The sealing transmission member also includes: A transmission shaft, passing through the sealing transmission member body, wherein a first end of the transmission shaft is connected to the servo motor, and a second end of the transmission shaft is connected to the filter wheel; Wherein, nano-magnetic liquid is arranged in the body of the sealing transmission component, which is configured to prevent air from entering the Dewar box.

5. The high frame rate filter switching mechanism under cold optics according to claim 4, characterized in that: The transmission mechanism also includes: The heat insulating pad is sleeved on the transmission shaft or the filter wheel adapter of the filter wheel and is configured to block heat conduction between the transmission mechanism and the filter wheel.

6. The high frame rate filter switching mechanism under cold optics according to claim 5, characterized in that: The surface of the thermal insulation pad is provided with a through hole, configured to increase the thermal resistance of the thermal insulation pad, and the through hole includes: a first through hole, the first through hole extending along the axial direction of the thermal insulation pad and penetrating the thermal insulation pad; A second through hole extends along the radial direction of the thermal insulation pad and penetrates the thermal insulation pad.

7. 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 disposed in the Dewar box and is configured to support the filter wheel and cool the filter wheel.

8. The high frame rate filter switching mechanism under cold optics according to claim 7, characterized in that: The low temperature cold plate comprises: The cooling unit is disposed on the low temperature cold plate and is configured to cool the filter.

9. The high frame rate filter switching mechanism under cold optics according to claim 8, characterized in that: The cooling unit comprises: A second through hole is provided through the low temperature cold plate to accommodate the filter; and / or A receiving groove is installed at the bottom of the second through hole and is used to accommodate the filter. Wherein, in response to the rotation of the filter wheel, the plurality of filters pass through the second through holes and / or the accommodating grooves in sequence.

10. The high frame rate filter switching mechanism under cold optics according to claim 2, characterized in that: The transmission mechanism also includes: A double diaphragm coupling connects the sealing transmission member to the filter wheel and is configured to adjust the axial deviation of the filter wheel caused by a low temperature environment.

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