A twin-eye imaging spectrometer system

Abstract

The application discloses a dual-aperture imaging spectrometer system and relates to the technical field of planetary atmosphere detection. The system comprises a dual-aperture imaging objective group, the dual-aperture imaging objective group comprising two groups of parallelly arranged sub-aperture objectives, the sub-aperture objectives being used for imaging ambient light information to form an intermediate image; a dual-telecentric imaging objective arranged at an image side of the dual-aperture imaging objective group and used for twice imaging the intermediate image and projecting the intermediate image to a position of a slit of a spectrometer; and a grating spectrometer comprising the slit, a dispersive element and an imaging camera, the slit being located at a predetermined slit image plane position of the spectrometer; wherein the dual-telecentric imaging objective is in a telecentric state at an object side and an image side, so that a chief ray of a light beam entering the slit after twice imaging is parallel to an optical axis of the system. The application aims to meet the requirements of miniaturization and light weight of a load device, and realize high spatial and temporal resolution and wide band detection.

Description

Technical Field

[0001] This invention relates to the fields of optical detection and planetary atmospheric exploration technology, and particularly to a binocular imaging spectrometer system. Background Technology

[0002] With the continuous development of deep space exploration technology, payload equipment in planetary atmospheric spectroscopic exploration needs to meet the requirements of miniaturization and lightweighting, while achieving high spatiotemporal resolution, wide spectral band, and high stability. Grating-type imaging spectrometers are a widely used spectroscopic instrument. Their systems typically consist of an imaging objective and a spectrometer. The imaging objective projects image information onto the spectrometer slit, where the spectrometer performs dispersive spectroscopy. However, existing imaging spectrometer systems mostly use a single imaging link and a single slit to transmit images, acquiring only one line of information from one image at a time. Furthermore, in specific modes such as occultation observations, their one-dimensional linear field of view is severely limited by physical size, resulting in low detection efficiency and making it difficult to achieve a balance between large field-of-view search and high-resolution staring.

[0003] Therefore, how to meet the requirements of miniaturization and lightweighting of payload equipment while achieving high spatiotemporal resolution and wide-band detection has become an urgent technical challenge. Summary of the Invention

[0004] The main objective of this invention is to provide a binocular imaging spectrometer system that aims to meet the requirements of miniaturization and lightweighting of the payload equipment while achieving high spatiotemporal resolution and wide-band detection.

[0005] To achieve the above objectives, the present invention proposes a binocular imaging spectrometer system, comprising: The binocular imaging objective group consists of two sets of parallel sub-eye objectives, which are used to image ambient light information to form an intermediate image. The dual telecentric imaging objective lens is set on the image side of the twin-eye imaging objective lens group and is used to perform secondary imaging of the intermediate image and project it onto the location of the slit of the spectrometer. And a grating spectrometer, which includes a slit, a dispersive element and an imaging camera, with the slit located at a predetermined slit image plane position of the spectrometer; Among them, the dual telecentric imaging objective lens is telecentric in both the object and image sides, so that the principal ray of the beam entering the slit after secondary imaging is parallel to the optical axis of the system.

[0006] Preferably, there are two sub-eye objectives, namely a first sub-eye objective and a second sub-eye objective; the focal length of the first sub-eye objective is... The focal length of the second sub-eye objective lens is .

[0007] Preferably, both the first sub-eye objective and the second sub-eye objective include an imaging lens and a field lens group; the imaging lens is used to image ambient light, and the field lens group is used to convert the imaging beam into an image-side telecentric beam and perform band selection.

[0008] Preferably, the imaging lens of at least one of the first sub-eye objective lens and the second sub-eye objective lens is a reverse telephoto type structure, comprising a negative lens as the first lens element and a positive lens group composed of multiple lenses for converging imaging; the focal length of the negative lens is... The focal length of the positive lens group is ,satisfy .

[0009] Preferably, the field lens group includes a plano-convex lens or biconvex lens with a focal length greater than 0, and a filter for selecting the measurement light band.

[0010] Preferably, the imaging magnification of the dual telecentric imaging objective is [value missing]. ,satisfy The dual telecentric imaging objective consists of a first part and a second part, the focal length of the first part being... Focal length of the second part Satisfying: The ratio of F1302 to F1301 is The absolute value of.

[0011] Preferably, the first part consists of a first meniscus lens, a second meniscus lens, and a third meniscus lens; the second part consists of a biconcave negative lens, a fourth meniscus lens, and a biconvex positive lens.

[0012] Preferably, the grating spectrometer includes a slit arranged sequentially along the optical path, a first plane mirror, an off-axis collimating focusing mirror, a convex aspherical grating as a dispersive element, a second plane mirror, and an imaging camera.

[0013] Preferably, the surface shape of the off-axis collimating focusing lens satisfies the standard even-order aspherical formula:

[0014] in, This indicates the aperture coordinates of the off-axis collimating focusing lens. The height of the arrow at the location, These are the coordinates of the reflected surface diameter. It is the conic coefficient. It is the curvature of the vertex of the aspherical surface. These are higher-order aspheric coefficients. It is the sequence number of the aspherical term. It is the total number of aspherical terms; off-axis collimating focusing lenses have off-axis properties. ,and .

[0015] Preferably, the scribe line density of the convex aspherical grating satisfy And its grating diffraction satisfies the following formula:

[0016] in, It is the angle of incidence of the grating. It is the grating diffraction angle. It is the wavelength of light. It is a diffraction order.

[0017] Preferably, the binocular imaging objective lens group further includes a first planar multi-angle reflector and a second planar multi-angle reflector, which are used to reflect ambient light beams to the first and second sub-eye objectives, respectively.

[0018] The above technical solution has the following advantages: The binocular imaging spectrometer system provided by this invention, by configuring an objective group containing two sets of parallel sub-eye objectives, can achieve multi-field stitching, independent viewing angle observation, or multi-band coverage according to detection requirements, significantly improving the system's detection flexibility and mission adaptability. Combined with dual telecentric imaging objectives that are telecentric in both the object and image sides, high-quality secondary imaging can be performed on the intermediate image formed by the sub-eye objectives, ensuring that the principal ray of the beam entering the spectrometer slit is always parallel to the system's optical axis. This effectively solves the aberration control problem in the optical path coupling process and ensures the stability of detection accuracy, enabling the system to achieve high-performance spectral imaging within a compact spatial envelope. Attached Figure Description

[0019] The present invention will now be described in detail with reference to specific embodiments and accompanying drawings, wherein: Figure 1 This is a schematic diagram of the structure of the binocular imaging spectrometer system provided in an embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram of the side-view principle of the binocular imaging spectrometer system provided in an embodiment of the present invention.

[0021] Figure 3 This is a schematic diagram of the structure of the sub-eye objective lens provided in an embodiment of the present invention.

[0022] Figure 4 This is a schematic diagram of the structure of a dual telecentric imaging objective lens provided in an embodiment of the present invention.

[0023] Figure 5 This is a schematic diagram of the structure of a grating spectrometer provided in an embodiment of the present invention.

[0024] Figure 6 This is a schematic diagram of the first structure of the binocular imaging objective lens assembly provided in an embodiment of the present invention.

[0025] Figure 7 This is a schematic diagram illustrating the definition of the off-axis amount of an off-axis collimating focusing lens provided in an embodiment of the present invention.

[0026] Figure 8 This is a schematic diagram of the structure of the first sub-eye objective lens provided in an embodiment of the present invention.

[0027] Figure 9 This is a schematic diagram of the structure of the second sub-eye objective lens provided in an embodiment of the present invention.

[0028] Figure 10 This is a schematic diagram of a second structure of the binocular imaging objective lens assembly provided in an embodiment of the present invention. Detailed Implementation

[0029] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application. See also... Figures 1 to 10 As shown.

[0030] Example 1 This embodiment provides a binocular imaging spectrometer system, which is mainly used in deep space exploration fields such as planetary atmospheric spectral detection. The system aims to meet the requirements of miniaturization and lightweighting of payload equipment while achieving high spatiotemporal resolution, high spectral resolution, and wide-band detection.

[0031] like Figure 1 and Figure 2 As shown, the binocular imaging spectrometer system mainly comprises a binocular imaging objective group 1, a dual telecentric imaging objective group 13, and a grating spectrometer 2. The binocular imaging objective group 1 is positioned at the front end of the optical path to collect ambient light information and form an intermediate image. The grating spectrometer 2 is positioned on the image side of the binocular imaging objective group 1 to perform dispersive spectral analysis on the intermediate image and record spectral image information.

[0032] The binocular imaging objective lens group 1 specifically includes two sets of parallel sub-eye objectives. In this embodiment, the number of sub-eye objectives is two, namely a first sub-eye objective 11 and a second sub-eye objective 12. The focal length of the first sub-eye objective 11 is defined as... The focal length of the second sub-eye objective lens 12 is defined as These two sub-eye objectives can have the same structural type to achieve field-of-view stitching, such as... Figure 6 As shown, different structural types or focal lengths can also be used to achieve variable field of view observation or multi-band coverage. Specific structures are as follows: Figure 10 As shown.

[0033] To guide light to the corresponding sub-eye objectives, the binocular imaging objective group 1 also includes a first planar multi-angle mirror and a second planar multi-angle mirror, collectively referred to as planar multi-angle mirror 101. The number of planar multi-angle mirrors 101 corresponds to the number of sub-eye objectives, and they are used to reflect ambient light beams to the first sub-eye objective 11 and the second sub-eye objective 12, respectively. By adjusting the angle between the planar multi-angle mirror 101 and the optical axis of the sub-eye objective, common-field observation or independent-view observation can be achieved. When the angles are equal, the system is a common-field optical path, and the object plane information observed by each sub-eye channel is the same; when the angles are unequal, each sub-eye channel can independently observe different spatial perspectives.

[0034] Both the first sub-eye objective 11 and the second sub-eye objective 12 consist of an imaging objective mirror system and a field lens group. For example... Figure 3 As shown, taking the first sub-eye objective lens 11 as an example, it includes a first imaging lens 1101 and a first field lens group 1102. The first imaging lens 1101 is used to perform preliminary imaging of ambient light. In a specific form of this embodiment, the first imaging lens 1101 adopts a reverse telephoto structure, including a negative lens as the first lens element and a positive lens group composed of multiple lenses for converging imaging.

[0035] The first lens is made of crown glass, and its refractive index is... satisfy Abbe number The focal length of the negative lens is... The focal length of the positive lens group is The two satisfy the absolute value relationship. This structure is advantageous for receiving beams with a wide field of view.

[0036] The first field lens group 1102 is located at the rear end of the first imaging lens 1101. It includes a plano-convex lens 1015 or a plano-convex positive lens 1025 with a focal length greater than 0. Its main function is to convert the imaging beams from each field of view into image-side telecentric beams to ensure the coupling efficiency of subsequent optical paths. In addition, the first field lens group 1102 also includes a filter 1016 for selecting the measurement light band. For example, the filter bands corresponding to the two sets of sub-eye objectives are respectively... and Furthermore, both the λ1 and λ2 bands are located in the range of 1500nm to 1600nm, thus enabling the selection of bands for different sub-eye channels.

[0037] The system also includes a set of dual telecentric imaging objectives 13, positioned on the image side of the sub-eye objective. The main function of the dual telecentric imaging objectives 13 is to perform secondary imaging of the intermediate image formed by the sub-eye objective and project it onto a predetermined slit position as input to the grating spectrometer 2. To ensure that the beam entering the spectrometer has good collimation characteristics, the dual telecentric imaging objectives 13 are telecentric in both the object and image sides, so that the principal ray of the beam entering the slit after secondary imaging is parallel to the optical axis of the system.

[0038] The imaging magnification of the dual telecentric imaging objective 13 is defined as follows: Its satisfaction The dual telecentric imaging objective 13 comprises a first part 1301 and a second part 1302, and the first part has a focal length of... With the second part of the focal length All are greater than 0. The focal length of the first part, 1301. Focal length of Part 2 1302 The ratio of F1302 to F1301 that satisfies the proportional relationship is: The absolute value. In terms of specific lens configuration, the first part 1301 consists sequentially along the optical path of a first meniscus lens 108, a second meniscus lens 109, and a third meniscus lens 110. The second part 1302 consists sequentially along the optical path of a biconcave negative lens 111, a fourth meniscus lens 112, and a biconvex positive lens 113. This specific lens combination can effectively correct various aberrations in the secondary imaging process.

[0039] The grating spectrometer 2 includes a slit 201, a dispersive element, an imaging camera 206, and a mirror to assist in the folding optical path. The specific structure is as follows: Figure 5 As shown, the optical path sequence inside the spectrometer is as follows: slit 201, first plane mirror 202, off-axis collimating focusing mirror 205, convex aspherical grating 204, second plane mirror 203, and imaging camera 206. Slit 201 is located at the projection position of the double telecentric imaging objective 13 and is used to intercept the line field of view to improve spectral resolution. The dispersive element is a convex aspherical grating 204. The first plane mirror 202 and the second plane mirror 203 are used to fold the optical path, making the system structure more compact. The magnification of the spectrometer system in the imaging dimension is [missing information]. Its satisfaction Preferred .

[0040] The off-axis collimating focusing lens 205 is used to collimate and project the light beam from the slit 201 onto the convex aspherical grating 204, while simultaneously converging and imaging the beam after diffraction by the grating. The focal length of the off-axis collimating focusing lens 205 is... satisfy Its surface shape satisfies the standard even-order aspherical formula as follows:

[0041] In this formula, These are the coordinates of the reflected surface diameter. It is the conic coefficient. It is the curvature of the vertex of the aspherical surface. These are higher-order aspheric coefficients. This refers to the aspherical term number, i.e., the aspherical order. This is the total number of aspherical terms. Off-axis collimating focusing lens 205 is an off-center region on a standard even-order aspherical lens, possessing an off-axis amount... Off-axis amount The setting within the range of 20 mm to 60 mm is to effectively avoid optical path obstruction between the off-axis collimating focusing lens 205 and the grating and mirror while ensuring system compactness.

[0042] refer to Figure 7 As shown, the central axis of a standard even-order aspherical lens is defined as... The central axis of the off-axis collimating focusing lens is Then off-axis amount That is, the central axis With central axis The distance between them, and satisfy .

[0043] The convex aspherical grating 204 is used to disperse and split a light beam, and its vertex radius of curvature is... ,satisfy The grating's line density satisfy Scale density The selection range of 20 lines / mm to 1000 lines / mm can balance the spectral resolution requirements and energy utilization of different bands in planetary atmosphere exploration.

[0044] The diffraction process of the grating satisfies the following formula:

[0045] In this formula, It is the angle of incidence of the grating. It is the grating diffraction angle. It is the wavelength of light. This refers to the diffraction order. The system can be adjusted by changing the diffraction order. With scale density The relationship, in order to satisfy the incident angle of each channel grating and diffraction angle Under the same conditions, different specific light bands are selected to broaden the spectral detection range. Finally, the imaging camera 206 receives and records the complete spectral image.

[0046] Example 2 Based on Embodiment 1, this embodiment provides a detailed description of the different structural forms of the sub-eye objectives in the binocular imaging objective lens group 1. Depending on the diverse needs of the detection mission, the sub-eye objectives in the binocular imaging objective lens group 1 can be configured with different structural types to achieve combined detection with different optical properties.

[0047] Specifically, the structural types of the first sub-eye objective lens 11 and the second sub-eye objective lens 12 can be different. For example Figure 8 and Figure 9 As shown, the first sub-eye objective lens 11 includes a first imaging lens 1101 and a first field lens group 1102. The first imaging lens 1101 adopts a reverse telephoto structure, which includes a sub-eye first meniscus lens 1011, a first lens 1012, a second meniscus sub-lens 1013, and a second lens 1014 arranged sequentially along the optical path. Among them, the sub-eye first meniscus lens 1011, which serves as the first lens element, is a negative lens with a focal length of [missing information]. The combined focal length composed of subsequent lenses If positive, both conditions are met. The relationship is as follows. The first field lens group 1102 includes a second plano-convex lens 1015 and a first filter 1016, wherein the main function of the second plano-convex lens 1015 is to convert the imaging beams of each field of view into image-side telecentric beams.

[0048] Based on the specific design of the first sub-eye objective lens 11, the optical parameters of each surface are shown in the table below.

[0049]

[0050] In the table, R represents the radius of curvature, d is the center thickness, nd is the refractive index of the material, and vd represents the Abbe number.

[0051] Correspondingly, the second sub-eye objective 12 includes a second imaging lens 1201 and a second field lens group 1202. The second imaging lens 1201 includes a third lens 1021, a third crescent lens 1022, a fourth crescent lens 1023, and a fourth lens 1024 arranged sequentially along the optical path for converging imaging. The second field lens group 1202 includes a plano-convex positive lens 1025 and a second filter 1026.

[0052] The specific optical parameters of the second sub-eye objective lens 12 are shown in the table below.

[0053]

[0054] In the table, R represents the radius of curvature; d is the center thickness; nd is the refractive index of the material; and vd represents the Abbe number.

[0055] Example 3 This embodiment provides supplementary explanations of the detailed parameters of the core components in the dual telecentric imaging objective 13 and the grating spectrometer 2. For example... Figure 4 As shown, the dual telecentric imaging objective 13 is responsible for accurately projecting the intermediate image onto the slit 201.

[0056] The detailed parameters of the dual telecentric imaging objective 13 are as follows.

[0057]

[0058] In the table, R represents the radius of curvature; d is the center thickness; nd is the refractive index of the material; and vd represents the Abbe number.

[0059] Surface profile parameters of the off-axis collimating focusing mirror 205 of the grating spectrometer 2. Conicity. for Second-order aspherical coefficient for 4th order aspherical coefficient for Off-axis amount of the off-axis collimating focusing lens 205 Preferred Specific values ​​within a certain range are used to avoid optical path obstruction. The radius of curvature of the convex aspherical grating 204 is... The scribe line density is Lines per millimeter, working diffraction order is class.

[0060] Example 4 This embodiment focuses on describing the application scenarios of the planar multi-angle mirror 101 under different detection modes. The binocular imaging objective lens group 1 is equipped with a set of planar multi-angle mirrors, namely the planar multi-angle mirror 101, the number of which is the same as the number of sub-eye objectives.

[0061] In the first application scenario, the optical axes of the two planar multi-angle mirrors are at equal angles to their respective sub-eye objectives. In this case, the system operates in a common-field mode, meaning that the environmental surface information observed by the first sub-eye objective 11 and the second sub-eye objective 12 is identical. By placing filters of different wavelengths in the two sub-eye channels, simultaneous multispectral detection of the same target area can be achieved.

[0062] In the second application scenario, the optical axes of the two planar multi-angle mirrors and their corresponding sub-eye objectives are not at the same angle. In this case, each sub-eye channel independently observes different spatial perspectives. By appropriately setting the angles, the two fields of view can be stitched together, thereby significantly increasing the overall field of view of the system without increasing the detector size.

[0063] Furthermore, by designing the first sub-eye objective lens 11 and the second sub-eye objective lens 12 with different focal lengths, namely... Not equal to It can achieve variable field of view detection. For example, a long focal length sub-eye can be used to achieve high-resolution staring observation of a local area of ​​the target, while a short focal length sub-eye can be used to search and observe a large area of ​​the background environment, thus achieving a multi-purpose detection effect.

[0064] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A twin-eye imaging spectrometer system, characterized by, Comprising: A binocular imaging objective lens group, which includes two sets of sub-eye objective lenses arranged in parallel. The sub-eye objective lenses are used to image environmental light information to form an intermediate image; The number of sub-eye objective lenses is two, namely the first sub-eye objective lens and the second sub-eye objective lens; The focal length of the first sub-eye objective lens is F11, and the focal length of the second sub-eye objective lens is F12; Both the first sub-eye objective lens and the second sub-eye objective lens include an imaging lens and a field lens group; the imaging lens is used to image environmental light, and the field lens group is used to convert the imaging beam into an image-side telecentric beam and perform wavelength band selection; A double telecentric imaging objective lens, arranged on the image side of the binocular imaging objective lens group, for performing secondary imaging on the intermediate image and projecting it to the position where the slit of the spectrometer is located; The imaging magnification of the double telecentric imaging objective lens is M, satisfying -1 < M < 0; the double telecentric imaging objective lens includes a first part and a second part, and the focal length F1301 of the first part and the focal length F1302 of the second part satisfy: the ratio of F1302 to F1301 is the absolute value of M; And a grating spectrometer, which includes a slit, a dispersion element, and an imaging camera. The slit is located at the predetermined slit image plane position of the spectrometer; Wherein, the double telecentric imaging objective lens is telecentric in both the object space and the image space, so that the chief ray of the beam entering the slit after secondary imaging is parallel to the optical axis of the system.

2. The double-eyepiece imaging spectrometer system according to claim 1, characterized in that: The imaging lens of at least one of the first sub-eye objective lens and the second sub-eye objective lens is an inverse telephoto type structure, which includes a negative lens as the first lens and a positive lens group composed of multiple lenses for converging imaging; the focal length of the negative lens is F111, and the focal length of the positive lens group is F112, satisfying: 。 3. The binocular imaging spectrometer system according to claim 1, characterized in that: The field lens group includes a plano-convex lens or a bi-convex lens with a focal length greater than 0, and a filter for selecting the measurement light wavelength band.

4. The binocular imaging spectrometer system according to claim 1, characterized in that: The first part is composed of a first meniscus lens, a second meniscus lens, and a third meniscus lens; the second part is composed of a double concave negative lens, a fourth meniscus lens, and a double convex positive lens.

5. The binocular imaging spectrometer system according to claim 1, characterized in that: The grating spectrometer includes a slit, a first plane mirror, an off-axis collimating focusing lens, a convex aspherical grating as the dispersion element, a second plane mirror, and an imaging camera arranged in sequence along the optical path.

6. The binocular imaging spectrometer system according to claim 5, characterized in that: The surface shape of the off-axis collimating focusing lens satisfies the standard even aspherical formula: Where z(r) represents the elevation of the off-axis collimating focusing lens at the aperture coordinate r, r is the aperture coordinate of the reflecting surface, k is the conic coefficient, and c is the curvature of the aspherical vertex. is the higher-order aspheric coefficient, i is the aspheric term index, and n is the total number of aspheric terms; the off-axis collimating focusing lens has an off-axis amount dc, and: .

7. The binocular imaging spectrometer system according to claim 5, characterized in that: The groove density lines of the convex aspherical grating satisfy: And its grating diffraction satisfies the following formula: in, It is the angle of incidence of the grating. It is the grating diffraction angle. It is the wavelength of light. It is a diffraction order.

8. The binocular imaging spectrometer system according to claim 1, characterized in that: The binocular imaging objective lens group further includes a first plane multi-angle mirror and a second plane multi-angle mirror, which are respectively used to reflect the environmental light beam to the first sub-eye objective lens and the second sub-eye objective lens.

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