A stray light suppression device for a hyperspectral detection equipment

Abstract

This invention discloses a stray light suppression device for a hyperspectral detection equipment, belonging to the field of optical detection technology. The device includes an incident aperture assembly, a collimating optics group, a filter assembly, a focusing optics group, and an exit aperture assembly arranged sequentially along the beam path. The filter assembly includes a limiting shell with a spherical inner wall, a partially spherical component rotatably disposed within the limiting shell and with its outer wall abutting it, multiple filters mounted on the partially spherical component, a driving assembly, an incident aperture, and an exit tube. The driving assembly drives the partially spherical component to rotate, thereby switching the filter located between the incident aperture and the exit tube. This invention utilizes the multi-degree-of-freedom rotation of the partially spherical component to achieve flexible filter switching, resulting in a compact structure suitable for miniaturized hyperspectral detection equipment.

Description

Technical Field

[0001] This invention relates to the field of optical detection technology, specifically to a stray light suppression device for hyperspectral detection equipment. Background Technology

[0002] Hyperspectral detection technology can simultaneously acquire spatial and spectral information of a target object, and has wide applications in remote sensing, environmental monitoring, agricultural assessment, and biomedicine. Hyperspectral detection equipment typically uses beam-splitting elements such as gratings, prisms, or filters to decompose an incident composite beam into spectral components of different wavelengths, which are then collected and analyzed by a detector.

[0003] Stray light is one of the key factors affecting the performance of hyperspectral detection equipment. Stray light refers to unwanted light radiation that arrives at the detector along a non-designed path. Its main sources include: residual reflection and scattering from the surface of optical elements, higher-order diffraction light from gratings, thermal radiation from internal structural components of the system, and intrusion of external ambient light. The presence of stray light reduces the contrast of the spectral signal, affects the accuracy of spectral reconstruction, and in severe cases, can even obscure weak signal targets, limiting the detection sensitivity and dynamic range of the equipment.

[0004] Existing stray light suppression methods mainly include setting fixed apertures and light shields in the optical path to limit the propagation of non-imaging beams, and setting fixed filters at the front end of the detector to block stray radiation outside a specific wavelength band. To meet the needs of multi-band detection, some devices use a rotating filter wheel structure to switch filters. However, existing solutions have the following shortcomings:

[0005] Firstly, fixed filters can only provide optimal suppression for a single preset band. When the detection task requires switching the working band, the cutoff characteristics of fixed filters may no longer be applicable, and may even cause unnecessary attenuation of the target band.

[0006] Secondly, in order to install and switch multiple filters, the rotary filter wheel requires a large-diameter turntable to arrange all the filters on the same circumference, resulting in a large filter wheel assembly, which is not conducive to the miniaturization and integration design of hyperspectral detection equipment.

[0007] Therefore, there is an urgent need for a stray light suppression device for hyperspectral detection equipment that can flexibly switch operating bands over a wide range while having a compact size. Summary of the Invention

[0008] (a) Technical problems to be solved

[0009] To address the shortcomings of existing technologies, this invention provides a stray light suppression device for hyperspectral detection equipment, which solves the aforementioned problems.

[0010] (II) Technical Solution

[0011] To achieve the above objectives, the present invention provides the following technical solution: a stray light suppression device for a hyperspectral detection equipment, comprising an incident aperture assembly, a collimating optical group, a filter assembly, a focusing optical group, and an exit aperture assembly arranged sequentially along the beam path;

[0012] The filter assembly includes a limiting shell, a partially spherical component, multiple filters, a driving assembly, an entrance aperture, and an exit tube;

[0013] The inner wall of the limiting shell is spherical, and the incompletely spherical component is rotatably disposed inside the limiting shell, with its outer wall fitting against the inner wall of the limiting shell.

[0014] Multiple of the aforementioned filters are mounted on the imperfectly spherical component;

[0015] The drive assembly is used to drive the incompletely spherical member to rotate in order to switch the filter located between the entrance aperture and the exit tube.

[0016] Preferably, the imperfectly spherical component includes a filter mounting component, an engaging component, and an auxiliary support component;

[0017] The filter mounting component is connected to the engaging component and the auxiliary support component on both sides respectively;

[0018] The outer walls of the filter mounting component, the engaging component, and the auxiliary support component are all partial spherical surfaces on the same spherical surface, together forming an incomplete spherical structure.

[0019] Preferably, the filter mounting component has multiple through holes for mounting the filter, and the through holes are arranged along a spherical surface.

[0020] Preferably, an elastic sealing ring is provided at the bottom end of the outlet tube, and the elastic sealing ring slides and seals against the inner wall surface of the filter mounting component. The fixed end of the elastic sealing ring is embedded in the mounting groove on the bottom end face of the outlet tube 36, and its free end has an arc-shaped contact surface, the radius of curvature of which is consistent with the spherical radius of the inner wall of the filter mounting component 321. In the assembled state, the arc-shaped contact surface is pressed against the inner wall surface of the filter mounting component 321 under the pre-tightening force of the elastic sealing ring itself. Because the elastic sealing ring has the ability to deform slightly in the radial and axial directions, when the filter mounting component 321 rotates around the center of the sphere under the drive of the drive assembly 34, the free end of the elastic sealing ring can adapt to the local tangential displacement of the sphere, always maintaining contact without jamming, thus achieving a balance between dynamic rotational sealing and low frictional resistance.

[0021] Preferably, the outer wall of the meshing member is provided with strip-shaped teeth arranged along the spherical surface for receiving driving torque from the drive assembly.

[0022] Preferably, the drive assembly includes a protective shell, a U-shaped frame, a drive gear, a driven gear, a gear ring, a bearing, a worm gear, a worm, a housing, a first motor, a second drive gear, and a third motor.

[0023] The drive gear is disposed within the U-shaped frame, and the driven gear is coaxially connected to the drive gear via a transmission shaft, which is connected to the U-shaped frame via the bearing.

[0024] The gear ring is located on the outside of the U-shaped frame and is not directly connected to the U-shaped frame. The driven gear meshes with the gear ring, and the gear ring is rotatably connected to the protective shell through the bearing.

[0025] The drive gear engages with the strip-shaped teeth of the meshing member.

[0026] Preferably, one end of the U-shaped frame is connected to the worm gear via a drive shaft, the worm gear meshes with the worm, the worm gear and the worm are disposed inside the housing, the housing is fixed to the protective shell, and the motor is connected to the worm gear via a drive.

[0027] The drive gear meshes with the gear ring, and the second motor is connected to the drive gear in a transmission manner.

[0028] Preferably, the drive gear has two rotational degrees of freedom: a first rotational direction that rotates about its own drive shaft axis, and a second rotational direction that rotates with the U-shaped frame about the worm gear drive shaft axis.

[0029] The second motor drives the active gear to rotate the gear ring, and through the driven gear, the drive gear rotates in the first direction, driving the incomplete spherical component to rotate in the first direction, thereby realizing the lateral switching of the filter.

[0030] The motor drives the worm gear to rotate, which in turn drives the drive gear to rotate in a second direction via the U-shaped frame, thereby causing the incomplete spherical component to rotate in a second direction and realizing the longitudinal switching of the filter.

[0031] When the first motor drives the drive gear to rotate in the second rotation direction, the second motor synchronously drives the driving gear to drive the gear ring to rotate in the same direction, so as to counteract the coupling rotation component generated by the driven gear, so that the drive gear only outputs the motion in the second rotation direction.

[0032] Preferably, the first motor and the second motor work together to make the drive gear simultaneously perform a compound motion in the first rotation direction and the second rotation direction, so as to switch the filter at any position on the filter mounting component to the working position between the entrance hole and the exit tube.

[0033] (III) Beneficial Effects

[0034] This invention provides a stray light suppression device for a hyperspectral detection apparatus. It has the following beneficial effects:

[0035] 1. This invention abandons the traditional rotary filter wheel method of arranging all filter planes on the same circumferential surface. Instead, it adopts a spherical array arrangement structure for the filter mounting components, arranging multiple filters along a three-dimensional spherical surface, making full use of the spherical space inside the limiting shell. Compared to a rotary filter wheel that accommodates the same number of filters, the spherical structure of this invention significantly reduces the projected size of the filter switching assembly on a two-dimensional plane, resulting in a more compact overall structure, which is significantly beneficial for the miniaturization and integrated design of hyperspectral detection equipment.

[0036] 2. By integrating multiple filters with different spectral transmission characteristics into a partially spherical component, and using a drive assembly to drive the partially spherical component to rotate freely within the limiting shell, the working band can be flexibly switched according to the detection task. Each working band corresponds to a specially designed filter that has been optimized, ensuring that each band can obtain the best out-of-band stray light suppression effect, overcoming the limitation of traditional fixed filter solutions that can only be optimized for a single band.

[0037] 3. The filter mounting components adopt a spherical array arrangement, which allows for the placement of more filters with different spectral characteristics within a limited space. The drive assembly, through the independent or combined motion of the first and second rotation directions of the drive gear, can switch filters at any position on the filter mounting components to the working position along the optimal path. Compared with the traditional single-axis rotary filter mechanism, which can only switch along a single circumferential path, this significantly improves the filter layout density and switching flexibility. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the structure of the present invention;

[0039] Figure 2 This is a schematic diagram of the internal structure of the present invention;

[0040] Figure 3 This is a schematic diagram of the structure of the filter assembly in this invention;

[0041] Figure 4 This is a schematic diagram of the internal structure of the filter assembly in this invention;

[0042] Figure 5 This is a schematic diagram of the structure of the incomplete spherical component in this invention;

[0043] Figure 6 This is a cross-sectional view of the filter mounting component in this invention;

[0044] Figure 7 This is a side view of the meshing component in the present invention;

[0045] Figure 8 This is a schematic diagram of the internal structure of the driving component in this invention;

[0046] Figure 9 This is a top view of the internal structure of the drive component in this invention.

[0047] Explanation of reference numerals in the attached diagram: Incident aperture assembly-1, Collimating optics group-2, Filter assembly-3, Focusing optics group-4, Exit aperture assembly-5;

[0048] Limiting shell-31, incomplete spherical component-32, filter-33, drive assembly-34, entrance hole-35, exit tube-36;

[0049] Filter mounting component-321, meshing component-322, strip-shaped retaining tooth-3221, auxiliary support component-323;

[0050] Protective shell-341, U-shaped frame-342, drive gear-343, driven gear-344, gear ring-345, bearing-346, worm gear-347, worm-shaft-348, housing-349, motor one-3410, drive gear-3411, motor two-3412. Detailed Implementation

[0051] In the description of this invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "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 used only for the convenience of describing the invention and for 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 invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0052] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0053] Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0054] Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0055] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0056] Please refer to Figure 1 and Figure 2 This embodiment provides a stray light suppression device for a hyperspectral detection equipment. The device consists of, from bottom to top, the following components arranged along the beam propagation path: an incident aperture assembly 1, a collimating optical group 2, a filter assembly 3, a focusing optical group 4, and an exit aperture assembly 5.

[0057] The incident aperture assembly 1 performs initial spatial filtering on the composite beam entering the device, limiting the beam's cross-sectional size and incident angle through a physical aperture to block large-angle stray radiation from entering subsequent optical paths. The collimating optics assembly 2 converts the divergent beam filtered by the incident aperture assembly 1 into a parallel beam, ensuring that the subsequent filter 33 operates under parallel light conditions and maintains its spectral selection accuracy. The filter assembly 3 is the core improved component of this invention, used to dynamically select the target operating wavelength from the parallel beam, achieving multiple suppressions of stray light in the process. The focusing optics assembly 4 refocuses the filtered target wavelength parallel beam. The exit aperture assembly 5 performs final spatial filtering and can also serve as the entrance slit for the subsequent hyperspectral spectrometer, feeding the high-purity target beam into the subsequent spectrometer.

[0058] In this embodiment, the incident aperture assembly 1, collimating optical group 2, focusing optical group 4, and exit aperture assembly 5 can all be implemented using conventional techniques known in the art, and their specific structures and functions will not be described in detail here. The above-mentioned components are common knowledge or conventional choices in the art. The core improvement of this invention lies in the structural design of the filter assembly 3 and its cooperative working method with the above-mentioned components. The filter assembly 3 of this invention will be described in detail below with reference to the accompanying drawings.

[0059] Please refer to Figure 3 and Figure 4 The filter assembly 3 includes a limiting shell 31, an incompletely spherical member 32, a filter 33, a driving assembly 34, an entrance hole 35, and an exit tube 36.

[0060] The limiting shell 31 provides a supporting and sealing base for the entire assembly, and its inner wall is spherical. The incompletely spherical member 32 is housed inside the limiting shell 31, and its outer wall is also spherical, fitting tightly against the inner wall of the limiting shell 31. Through this spherical fit, the limiting shell 31 provides a geometric constraint on the incompletely spherical member 32, allowing it to rotate freely around its own center without translational displacement.

[0061] The inner wall region of the imperfectly spherical component 32 is integrated with multiple filters 33 with different spectral transmission characteristics, forming a filter array. The drive assembly 34 is mounted and fixed to the side wall of the limiting shell 31, and is used to output driving torque to drive the imperfectly spherical component 32 to rotate as needed.

[0062] An entrance aperture 35 is provided at the bottom center of the limiting shell 31, and the bottom of the entrance aperture 35 is optically aligned with the collimating optical group 2. An exit tube 36 is vertically arranged on the upper side inside the limiting shell 31, and the top of the exit tube 36 is optically aligned with the focusing optical group 4. At any given time, a filter 33 is precisely switched and positioned on the optical axis between the entrance aperture 35 and the exit tube 36. The parallel beam from the collimating optical group 2 enters the limiting shell 31 through the entrance aperture 35, passes through the currently working filter 33 to complete spectral selection, and is then led out to the focusing optical group 4 through the exit tube 36. When it is necessary to switch the working band, the drive assembly 34 drives the incompletely spherical component 32 to rotate, moving the target filter 33 to the working position between the entrance aperture 35 and the exit tube 36.

[0063] It should be noted that the filter 33 used in this embodiment is itself prior art. Specifically, the filter 33 can be a type commonly used in the art, such as a narrowband interference filter, bandpass filter, long-wavelength pass filter, or short-wavelength pass filter. These types of filters are typically fabricated from a multilayer dielectric film system through a vacuum coating process. Based on the principle of thin-film interference, they can achieve high transmittance of light beams in a specific wavelength band, while reflecting or absorbing light beams in non-target wavelength bands. Its optical parameters, such as center wavelength, half-bandwidth, and peak transmittance, can be customized according to the actual needs of hyperspectral detection. The relevant manufacturing and application technologies are well known to those skilled in the art and will not be elaborated upon here.

[0064] Please refer to Figure 5 Furthermore, the incomplete spherical component 32 is composed of three parts: a filter mounting component 321, an engaging component 322, and an auxiliary support component 323.

[0065] The filter mounting component 321 is located in the bottom region of the incomplete spherical component 32, and its left and right sides are respectively connected to the engaging component 322 and the auxiliary support component 323. The outer walls of the filter mounting component 321, the engaging component 322 and the auxiliary support component 323 are all local spherical surfaces on the same spherical surface, which are spliced ​​together to form an incomplete spherical shell structure. The exit tube (36) is fixedly installed on the top of the limiting shell (31), and an elastic sealing ring is embedded at its bottom end. The end face of the elastic sealing ring forms a sliding contact seal with the inner wall surface of the filter mounting component (321). The elastic sealing ring is made of a low-friction coefficient, high-wear-resistant elastic material (such as polytetrafluoroethylene composite material or fluororubber), and its end face is machined into an arc-shaped contact surface that matches the radius of curvature of the spherical surface of the inner wall of the filter mounting component (321). When the incompletely spherical component 32 rotates around the center of the sphere in the limiting shell 31 with multiple degrees of freedom, the elastic sealing ring relies on its own elastic deformation to always maintain close contact with the inner wall of the filter mounting component (321), which allows the spherical surface to slide freely and effectively blocks the leakage of the light beam at the interface between the bottom end of the exit tube and the inner wall of the filter mounting component, thereby ensuring the continuity of the optical path under all operating conditions.

[0066] Please refer to Figure 5 and Figure 6 The filter mounting component 321 has multiple through holes arranged along the spherical surface inside, each through hole for fixing a filter 33. By driving the filter mounting component 321 to rotate in different directions, the filter 33 at any position in the array can be switched to the optical axis between the entrance aperture 35 and the exit tube 36.

[0067] The engaging member 322 and the auxiliary support member 323 are arranged symmetrically with respect to the filter mounting member 321. Please refer to... Figure 7 The outer wall of the engaging member 322 is machined with strip-shaped teeth 3221 arranged along the spherical surface. These strip-shaped teeth 3221 are used to receive the driving torque from the drive assembly 34. Each strip-shaped tooth 3221 has a V-shaped groove structure in the side view. The auxiliary support member 323 ensures that no matter what position the filter mounting member 321 is rotated to, the outer wall of the auxiliary support member 323 is always tightly attached to and supported on the inner wall of the limiting shell 31. Working together with the engaging member 322, it ensures that the entire incompletely spherical member 32 will not detach from the inner wall surface of the limiting shell 31 in any rotational position, thereby ensuring its positioning accuracy and sealing effect.

[0068] Please refer to Figure 8 and Figure 9To achieve multi-degree-of-freedom precision driving of the imperfectly spherical component 32, the drive assembly 34 specifically includes a protective shell 341, a U-shaped frame 342, a drive gear 343, a driven gear 344, a gear ring 345, a bearing 346, a worm gear 347, a worm 348, a housing 349, a first motor 3410, a driving gear 3411, and a second motor 3412.

[0069] The protective shell 341 is a closed shell, fixedly installed on the outer wall of the limiting shell 31. A U-shaped frame 342 is provided in the middle section of the interior of the protective shell 341. The drive gear 343 is installed inside the opening of the U-shaped frame 342. In this embodiment, two driven gears 344 are preferably provided, located on opposite sides of the U-shaped frame 342. The two driven gears 344 are coaxially connected to the drive gear 343 via the same transmission shaft. This transmission shaft forms a rotational support with the U-shaped frame 342 through bearings, enabling the U-shaped frame 342 to stably support the drive gear 343 and the driven gears 344.

[0070] The gear ring 345 is located on the periphery of the U-shaped frame 342, but is not directly connected to the U-shaped frame 342. Gear teeth are machined on both the left and right sides of the gear ring 345, and two driven gears 344 mesh with the corresponding gear teeth on the sides of the gear ring 345. The outer circumference of the gear ring 345 is rotatably connected to the inner wall of the protective shell 341 via a bearing 346, allowing the gear ring 345 to rotate smoothly around its own axis within the protective shell 341.

[0071] The left end of the U-shaped frame 342 is fixedly connected to the worm gear 347 via a drive shaft. The worm gear 347 meshes with the worm 348, and both are encapsulated inside the housing 349. The housing 349 is fixedly connected to the left side wall of the protective shell 341. The motor 3410 is mounted on the outer wall of the housing 349, and its drive shaft is connected to the worm 348 to provide rotational power for the worm 348.

[0072] The drive gear 3411 is located inside the protective housing 341, and its teeth mesh with the teeth on the left side of the gear ring 345, which is used to actively drive the gear ring 345 to rotate. The motor 3412 is mounted on the outer wall of the protective housing 341, and its drive shaft is connected to the drive gear 3411 to provide rotational power for the drive gear 3411.

[0073] The outer circumferential surface of the drive gear 343 is machined with a toothed structure, which precisely meshes with the V-shaped grooved strip teeth 3221 on the meshing member 322. This meshing method has a self-locking characteristic, which can prevent the meshing member 322 from rotating on its own due to external force or inertia when it is not receiving driving force.

[0074] In this embodiment, both motor 3410 and motor 3412 can be two-phase hybrid stepper motors known in the art. A stepper motor is an open-loop control motor that converts electrical pulse signals into angular displacement. It has been widely used in the field of optical precision positioning. For example, in the rotating filter system of a multispectral optical detection system, a stepper motor drives a rotating disk to rotate by a certain angle, thereby achieving the switching of different wavelength filters. In the filter switching wheel mechanism, the stepper motor drives the rotating disk to rotate, and in conjunction with a zero-point positioning switch, achieves precise positioning of the filter assembly. In the electro-optical objective lens converter, a decelerated stepper motor, in conjunction with a Hall effect detection board, can drive a rotating plate to rotate the target objective lens to the position of the light-transmitting aperture. The above applications demonstrate that stepper motors can meet the positioning accuracy requirements for filter or lens switching in optical equipment. The relevant control technology of stepper motors is common knowledge in the art, and its specific drive circuits and control algorithms will not be elaborated here.

[0075] With the above structure, the drive gear 343 has two independent rotational degrees of freedom. For ease of description, the rotation of the drive gear 343 about its own transmission shaft axis is defined as the first rotational direction, i.e., axial rotation; the rotation of the drive gear 343 along with the U-shaped frame 342 about the worm gear transmission shaft axis is defined as the second rotational direction.

[0076] When the drive gear 343 rotates only in the first rotation direction, its tooth profile drives the meshing bar-shaped locking tooth 3221, which in turn drives the meshing member 322 and the entire incomplete spherical member 32 to rotate in the first rotation direction, thereby realizing the lateral switching between the filters 33 in each row on the filter mounting member 321.

[0077] When the U-shaped frame 342 drives the drive gear 343 to rotate in the second direction, the drive gear 343 drives the meshing part 322 and the entire incomplete spherical component 32 to rotate in the first direction, thereby realizing the longitudinal switching between the rows of filters 33 on the filter mounting part 321.

[0078] When it is necessary to switch a filter 33 located at an oblique position on the filter mounting component 321 to the working position, the control system controls the drive gear 343 to perform a compound motion in the first rotation direction and the second rotation direction at the same time, so that the oblique filter 33 can be accurately moved to the optical axis between the entrance hole 35 and the exit tube 36 through the optimal path.

[0079] Based on the above settings regarding the degree of freedom and direction of filter switching, the transmission principle and control logic of the drive component 34 under three typical switching conditions will be explained one by one below.

[0080] Scenario 1: Switching between left and right filters.

[0081] This operating condition requires the drive gear 343 to generate pure rotational movement in the first direction. The system control motor 3412 starts, driving the drive gear 3411 to rotate, which in turn drives the gear ring 345 to rotate. At this time, because the worm gear 347 and worm 348 are in a self-locking state, the U-shaped frame 342 is rigidly locked in its current position, thus preventing the drive gear 343 from generating rotational movement in the second direction. Therefore, the rotational force of the gear ring 345 can only drive the two driven gears 344 meshing with it to rotate. The driven gears 344 drive the drive gear 343 to rotate synchronously in the first direction via the transmission shaft. The rotation of the drive gear 343 is transmitted to the meshing member 322 via the strip-shaped retaining teeth 3221, driving the entire incompletely spherical component 32 to rotate in the left and right directions, completing the lateral position switching of the filter 33.

[0082] Scenario 2: Switching between filters in the front and back directions.

[0083] This operating condition requires the drive gear 343 to generate a purely second rotational direction motion. The system control motor 3410 starts, driving the worm gear 348 to rotate, which in turn drives the worm wheel 347 to rotate. The worm wheel 347 drives the U-shaped frame 342, along with the drive gear 343 and driven gear 344 on it, to rotate in the second rotational direction via the transmission shaft. During this process, since the driven gear 344 remains meshed with the stationary gear ring 345, while following the U-shaped frame 342 in the second rotational direction, the driven gear 344 generates a coupled first rotational direction component. To precisely counteract this undesirable motion component, the control system synchronously starts the second motor 3412, driving the drive gear 3411 to drive the gear ring 345 to rotate at a precisely matched speed and direction, so that the meshing point of the driven gear 344 on the gear ring 345 is relatively stationary, thereby ensuring that the drive gear 343 outputs only a purely second rotational direction motion. The drive gear 343 drives the meshing part 322 and the entire incomplete spherical component 32 to rotate in the front and back directions, thereby completing the longitudinal position switching of the filter 33.

[0084] Scenario 3: Filter switching at an angle.

[0085] When there is a row or column deviation between the current coordinates of the target filter 33 on the filter mounting part 321 and the target coordinates, the control system coordinates the synchronous operation of motor 1 3410 and motor 2 3412 according to the difference calculation result, so that the drive gear 343 simultaneously outputs the combined motion of the first rotation direction and the second rotation direction, driving the incomplete spherical component 32 to rotate along the combined path, and switching the target filter 33 to the working position between the entrance hole 35 and the exit tube 36 with the optimal path.

[0086] Throughout the switching process, the inner spherical surface of the limiting shell 31 and the outer spherical surface of the incompletely spherical component 32 remain in close contact, ensuring the continuous optical seal of the internal cavity of the filter assembly 3 and effectively suppressing stray light and dust.

[0087] The stray light suppression device provided in this embodiment has the following overall working process.

[0088] The first step is beam collimation and preliminary spatial filtering.

[0089] The composite beam to be detected first enters the incident aperture assembly 1. The incident aperture assembly 1 precisely limits the cross-sectional size and incident angle of the incident beam through its physical aperture, initially blocking stray radiation at large angles and allowing only beams conforming to the designed aperture and field of view to enter the subsequent optical path. The pre-filtered beam then enters the collimating optics group 2, which converts the diverging beam into a parallel beam. The purpose of collimating the beam is to ensure that the subsequent filter 33 operates in a parallel optical path, thereby guaranteeing that the spectral characteristics of its coating are not affected by changes in the incident angle and maintaining high-precision spectral selectivity.

[0090] The second step is dynamic spectral selection and core stray light suppression.

[0091] The parallel light beam emitted from the collimating optical group 2 enters the filter assembly 3 through the entrance hole 35 at the bottom of the limiting shell 31. After passing through the entrance hole 35, the collimated light beam directly illuminates the currently operating filter 33, which is directly opposite the bottom of the exit tube 36. Based on its coating characteristics, the filter 33 highly transmits light in the target wavelength band and effectively reflects or absorbs unwanted out-of-band stray light. The out-of-band stray light reflected by the filter 33 diverges at a specific angle into the interior space of the limiting shell 31. Since the limiting shell 31 and the imperfectly spherical member 32 form a nearly sealed spherical cavity, these reflected stray lights undergo multiple reflections between the inner walls of the cavity. Each reflection significantly attenuates the energy of the light-absorbing coating on the inner wall until it is completely absorbed, thus preventing it from entering the subsequent detector through the exit tube 36. The target wavelength beam, precisely selected by the filter 33, passes through the bottom end of the exit tube 36, which is attached to the filter mounting component 321, and is guided into the focusing optical group 4.

[0092] The third step is to switch filters as needed.

[0093] When it is necessary to switch the working band according to different detection tasks, the control system automatically determines the switching type and executes the corresponding driving logic based on the position coordinates of the target filter. The driving component 34 drives the incomplete spherical component 32 to rotate in two dimensions within the limiting shell 31, so as to accurately switch the required filter 33 to the working position.

[0094] The fourth step is beam focusing and final spatial filtering.

[0095] The parallel beam of the target wavelength emitted from the exit tube 36 enters the focusing optics group 4. The focusing optics group 4 refocuses the parallel beam and focuses it onto the exit aperture assembly 5. While receiving the focused beam, the exit aperture assembly 5 performs a final spatial filtering procedure to intercept the small amount of residual stray light generated by reflection and scattering inside the device, allowing only the high-purity target beam to enter the subsequent spectrometer for dispersion and detection.

[0096] The control method of this invention is automatic control through a controller. The control circuit of the controller can be implemented by simple programming by those skilled in the art. The power supply is also common knowledge in the art. Furthermore, since this invention is mainly used to protect mechanical devices, the control method and circuit connection will not be explained in detail here.

[0097] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A stray light suppression device for a hyperspectral detection apparatus, characterized in that, It includes an incident aperture assembly (1), a collimating optical group (2), a filter assembly (3), a focusing optical group (4), and an exit aperture assembly (5) arranged sequentially along the beam path; The filter assembly (3) includes a limiting shell (31), an incompletely spherical component (32), multiple filters (33), a driving assembly (34), an entrance hole (35), and an exit tube (36). The inner wall of the limiting shell (31) is spherical, and the incomplete spherical member (32) is rotatably disposed inside the limiting shell (31), with its outer wall fitting against the inner wall of the limiting shell (31). Multiple filters (33) are mounted on the imperfectly spherical member (32); The drive assembly (34) is used to drive the incomplete spherical member (32) to rotate in order to switch the filter (33) located between the entrance hole (35) and the exit tube (36).

2. The stray light suppression device for a hyperspectral detection apparatus according to claim 1, characterized in that, The imperfect spherical component (32) includes a filter mounting component (321), a meshing component (322), and an auxiliary support component (323). The filter mounting component (321) is connected to the engaging component (322) and the auxiliary support component (323) on both sides respectively. The outer walls of the filter mounting component (321), the engaging component (322), and the auxiliary support component (323) are all local spherical surfaces on the same spherical surface, which together constitute an incomplete spherical structure.

3. The stray light suppression device for a hyperspectral detection apparatus according to claim 2, characterized in that, The filter mounting component (321) has a plurality of through holes for mounting the filter (33), and the through holes are arranged along the spherical surface.

4. The stray light suppression device for a hyperspectral detection apparatus according to claim 2, characterized in that, An elastic sealing ring is provided at the bottom end of the outlet tube (36), and the elastic sealing ring slides and seals against the inner wall surface of the filter mounting component (321).

5. The stray light suppression device for a hyperspectral detection apparatus according to claim 2, characterized in that, The outer wall of the meshing member (322) is provided with strip-shaped teeth (3221) arranged along the spherical surface for receiving driving torque from the drive assembly (34).

6. The stray light suppression device for a hyperspectral detection apparatus according to claim 5, characterized in that, The drive assembly (34) includes a protective shell (341), a U-shaped frame (342), a drive gear (343), a driven gear (344), a gear ring (345), a bearing (346), a worm gear (347), a worm (348), a housing (349), a motor one (3410), a drive gear (3411), and a motor two (3412). The drive gear (343) is disposed inside the U-shaped frame (342), and the driven gear (344) is coaxially connected to the drive gear (343) through a transmission shaft. The transmission shaft is connected to the U-shaped frame (342) through the bearing (346). The gear ring (345) is located on the outside of the U-shaped frame (342) and is not directly connected to the U-shaped frame (342). The driven gear (344) meshes with the gear ring (345). The gear ring (345) is rotatably connected to the protective shell (341) through the bearing (346). The drive gear (343) engages with the strip teeth (3221) of the meshing member (322).

7. The stray light suppression device for a hyperspectral detection apparatus according to claim 6, characterized in that, One end of the U-shaped frame (342) is connected to the worm gear (347) via a drive shaft. The worm gear (347) meshes with the worm (348). The worm gear (347) and the worm (348) are disposed inside the housing (349). The housing (349) is fixed to the protective shell (341). The motor (3410) is connected to the worm (348). The drive gear (3411) meshes with the gear ring (345), and the second motor (3412) is connected to the drive gear (3411) in a transmission connection.

8. The stray light suppression device for a hyperspectral detection apparatus according to claim 7, characterized in that, The drive gear (343) has two rotational degrees of freedom: a first rotational direction that rotates about its own transmission shaft axis, and a second rotational direction that rotates with the U-shaped frame (342) about the transmission shaft axis of the worm gear (347).

9. The stray light suppression device for a hyperspectral detection apparatus according to claim 7, characterized in that, The first motor (3410) and the second motor (3412) work together to make the drive gear (343) perform a compound motion in the first rotation direction and the second rotation direction at the same time, so as to switch the filter (33) at any position on the filter mounting part (321) to the working position between the entrance hole (35) and the exit tube (36).

Images