A spectral camera with a full-refractive front group

Abstract

The utility model provides a kind of spectral camera with total refraction front lens group, belong to spectral imaging technical field.Spectral camera includes front lens group, slit component, collimating lens group, grating and wedge plate combination, collection lens group and detector component sequentially along optical axis;Scan mirror is galvanometer or rotary mirror structure, using plated metal glass substrate;Front lens group is total refraction type multi-lens combination architecture, is coaxially close to the arrangement consisting of three pieces thick meniscus negative lens, two groups of double cemented lens, positive focal length meniscus lens and positive focal length lenticular lens;Collimating lens group and collection lens group are symmetric design, grating and wedge plate combination use sealed interface installation.This device expands field of view coverage by optimizing structure layout and component design, effectively corrects multiple aberrations, improves transmittance and working stability, realizes miniaturization design.

Description

Technical Field

[0001] This utility model relates to the field of spectral imaging technology, and in particular to a spectral camera with a fully refractive front mirror group. Background Technology

[0002] The optical device of a hyperspectral camera is the core component for realizing spectral imaging. It is widely used in remote sensing, environmental monitoring, industrial inspection, biomedical imaging and other fields. It obtains the hyperspectral data cube of the target by collecting, splitting and imaging the target light.

[0003] Existing optical devices for hyperspectral cameras still suffer from several technical shortcomings in practical applications: First, the design of the front lens group has limitations. Current solutions often employ combinations of thin lenses or a single type of lens architecture. Thin lenses are prone to beam deflection and overflow at the edges of the field of view under large fields of view. Furthermore, a single lens cannot simultaneously correct spherical aberration, coma, astigmatism, and wide-band chromatic aberration, resulting in blurred image edges and distorted color reproduction. Although some solutions use multi-lens combinations, the air gaps between lenses are too large, the layout is loose, and the overall size is too large, making it unsuitable for the installation requirements of miniaturized devices. Second, the lens materials and structural design of the front lens group are unreasonable. Most lenses use ordinary optical glass, and the anti-reflection coating on the surface covers a limited wavelength, resulting in significant light loss and stray light problems. Thin lenses, on the other hand, cannot effectively balance the field of view. Third, there is insufficient stray light interception. Existing devices mostly use external apertures, which either have poor stray light interception or block the imaging beam, affecting imaging efficiency. The design of internal apertures has not been reasonably applied in the current technology. Fourth, the collimating lens group and the collecting lens group often adopt an asymmetrical design, making it difficult to effectively correct aberrations such as field curvature and distortion after beam splitting, resulting in insufficient clarity of the spectral image. Fifth, the installation structure of the grating and wedge plate combination lacks a sealed design, making it susceptible to interference from environmental factors such as dust and moisture, reducing the reliability of the device. In addition, the coupling accuracy between the slit assembly and the front lens group is not well controlled, resulting in poor imaging quality of the primary image plane and poor linear beam encoding effect in subsequent beam splitting processing, ultimately affecting the acquisition accuracy of hyperspectral data. Summary of the Invention

[0004] To address the technical shortcomings of existing hyperspectral camera optical devices, such as small scanning mirror field of view, poor broadband reflectivity and unstable dynamic scanning imaging, insufficient aberration correction of the front mirror group, easy beam overflow at the edge of the field of view, large size and low long-term working stability, poor stray light interception effect, insufficient aberration correction after beam splitting due to the asymmetrical design of the collimating and collecting mirror groups, and poor device sealing and susceptibility to environmental interference, this utility model provides an optical device for a hyperspectral camera to solve the above problems.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution.

[0006] A spectroscopic camera with a fully refractive front mirror assembly includes a front mirror assembly, a slit assembly, a collimating mirror assembly, a grating and wedge plate assembly, a collecting mirror assembly, and a detector assembly arranged sequentially along the optical axis. The scanning mirror is located at the front of the camera. The target incident window is adjacent to the rear of the scanning mirror and is directly connected to the front mirror assembly. The front mirror assembly is a fully refractive multi-lens assembly structure and is coupled to the slit assembly. The slit assembly is located at the primary image plane. The collimating mirror assembly is located behind the slit assembly. The grating and wedge plate assembly is located between the collimating mirror assembly and the collecting mirror assembly. The collecting mirror assembly is located behind the grating and wedge plate assembly, and the detector assembly is located behind the collecting mirror assembly.

[0007] In a preferred embodiment of this utility model, the front lens group includes, in sequence according to the beam propagation direction, a first thick meniscus negative lens, a second thick meniscus negative lens, a third thick meniscus negative lens, a positive power cemented doublet lens, a negative power cemented doublet lens, a positive power meniscus lens, and a positive power biconvex lens, with each lens arranged coaxially.

[0008] In a preferred embodiment of this utility model, the object-side radius of curvature of the first thick meniscus negative lens is 16mm, the image-side radius of curvature is 6mm, and the lens thickness is 12mm.

[0009] In a preferred embodiment of this utility model, the object-side radius of curvature of the second thick meniscus negative lens is -7mm, the image-side radius of curvature is -21mm, and the lens thickness is 9mm.

[0010] In a preferred embodiment of this utility model, the third thick meniscus negative lens has an object-side curvature radius of 10mm, an image-side curvature radius of 8mm, and a lens thickness of 3mm.

[0011] In a preferred embodiment of this utility model, the object-side radius of curvature of the positive power cemented doublet is 7mm, the image-side radius of curvature is -6mm, and the total thickness of the lens is 4mm; an aperture stop is provided between the positive power cemented doublet and the negative power cemented doublet, and the aperture stop is a standard circular aperture stop with the aperture plane perpendicular to the optical axis.

[0012] In a preferred embodiment of this utility model, the negative power cemented doublet has a lens thickness of 1 mm; the positive power meniscus has an image-side radius of curvature of 4 mm and a lens thickness of 4 mm; the positive power biconvex lens has an object-side radius of curvature of 6 mm, an image-side radius of curvature of 7 mm, and a lens thickness of 5 mm.

[0013] In a preferred embodiment of this invention, the edge of the slit assembly is polished or coated; the slit assembly is adjacent to the image plane of the front lens group and directly docks with the collimating lens group.

[0014] In a preferred embodiment of this invention, the collimating lens group and the collecting lens group are symmetrical structures, both composed of double or triple lenses; the incident surface of the collimating lens group coincides with the slit image plane.

[0015] In a preferred embodiment of this utility model, the grating in the grating and wedge plate assembly is a transmission grating, and the grating and wedge plate assembly is installed by a rotating bracket or adjustment platform, and the interface with the front and rear lens groups adopts a sealed design; the chip of the detector assembly is a CMOS or CCD sensor, which is connected to the camera body through a C interface or an F interface.

[0016] Compared with the prior art, the advantages of this utility model are as follows: The front lens group adopts a fully refractive multi-lens combination architecture. Through the collaborative design of three thick meniscus negative lenses, it effectively balances the beam deflection angle at the edge of the field of view to avoid overflow, while correcting aberrations such as spherical aberration, coma, and astigmatism. It is paired with positive and negative optical power cemented doublet lenses, which utilize the complementarity of different dispersion characteristics of glass to achieve accurate correction of chromatic aberration over a wide band. The subsequent meniscus lens and biconvex lens further optimize beam parallelism and image plane accuracy.

[0017] The lenses in the front lens group are arranged in a close-fitting manner (with an air gap of 0.3mm), and the third thick meniscus negative lens adopts a 3mm thin design, which greatly reduces the overall volume of the lens group; the thin structure reduces stress deformation caused by the lens's own weight.

[0018] The lens surface is coated with multiple anti-reflection films, increasing the light transmittance to over 96% and reducing light loss; the built-in aperture stop is placed between two sets of cemented doublet lenses, effectively blocking stray light without obstructing the effective imaging beam, thus improving image quality.

[0019] The collimating lens group and the collecting lens group adopt a symmetrical design to minimize aberrations such as field curvature and distortion after spectral dispersion, ensuring clear spectral images; the combination of grating and wedge plate adopts a sealed interface design to avoid environmental interference and improve the reliability of the device.

[0020] The slit assembly is positioned at the primary image plane and precisely coupled with the front mirror group, ensuring the accuracy of the linear beam encoding and providing a high-quality beam foundation for subsequent beam splitting. Attached Figure Description

[0021] Figure 1 A schematic diagram of the optical lens group structure and optical path of a spectrometer camera with a fully refractive front mirror group provided in the first embodiment of this utility model; Figure 2 This is a detailed structural and optical path diagram of the front mirror group in the spectral camera with a fully refractive front mirror group provided in the first embodiment of this utility model.

[0022] The reference numerals in the attached figures are as follows: 1: Scanning mirror, 2: Target entrance window, 3: Front mirror group, 4: Slit assembly, 5: Collimating mirror group, 6: Grating and wedge plate combination, 7: Collecting mirror group, 31: First thick meniscus negative lens, 32: Second thick meniscus negative lens, 33: Third thick meniscus negative lens, 34: Positive power cemented doublet lens, 35: Aperture stop, 36: Negative power cemented doublet lens, 37: Positive power biconvex lens. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this utility model clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this utility model and are not intended to limit its scope.

[0024] The technical solutions of the present invention will now be clearly and completely described with reference to the accompanying drawings of the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them.

[0025] like Figure 1 and Figure 2 As shown, in the first embodiment of this utility model, a spectroscopic camera with a fully refractive front mirror assembly is provided, including a scanning mirror 1, a target incident window 2, a front mirror assembly 3, a slit assembly 4, a collimating mirror assembly 5, a grating and wedge plate assembly 6, a collecting mirror assembly 7, and a detector assembly, etc. These components are arranged sequentially along the optical axis to form a complete optical path, ensuring continuous processing of light from target incident to data acquisition.

[0026] The scanning mirror 1 is used to dynamically scan the observed target to expand the field of view of the device or to achieve stable imaging of the moving platform. The scanning mirror 1 is located at the foremost position of the optical device of the hyperspectral camera; light first enters its surface and is then reflected and guided to subsequent components. The scanning mirror 1 is made of a highly reflective material, such as an aluminum- or silver-plated glass substrate, ensuring excellent reflectivity over a wide spectral range of 400 nm to 1000 nm.

[0027] Preferably, the scanning mirror 1 is a galvanometer or rotating mirror structure, which can be precisely adjusted by a motor drive, with a field of view of not less than ±12 degrees. The scanning mirror 1 is an image stabilization mechanism, which can be fixed to the device housing by a three-point titanium alloy / high-strength aluminum alloy precision support. An elastic damping pad is provided at the bottom of the support, which can counteract the effects of airflow disturbances and attitude tilt when the hyperspectral camera is installed on a mobile carrier such as a drone, achieving stable imaging. Optionally, a quartz glass dust cover can be provided on the outside of the mirror body, connected to the housing through a labyrinth-type sealing structure to achieve dust and moisture protection.

[0028] More preferably, the scanning mirror 1 is fixed to the optical housing of the hyperspectral camera (not shown) by a precision mechanical support (not shown in the figure) and directly docked with the target incident window 2 to ensure optical center alignment.

[0029] The target incident window 2 is the entrance portion of the optical device of the hyperspectral camera, where light enters and forms the starting point of the optical path. Target incident window 2 is located immediately behind the scanning mirror 1 and directly connected to the front mirror group 3. It is fixed to the main body of the hyperspectral camera's optical device by a mechanical sealing ring (not shown in the figure) to prevent dust and moisture intrusion. In a practical application scenario, the target incident window 2 is a logical window, not a physical window; that is, a manually defined incident window.

[0030] The front lens group 3 is used to perform initial imaging of the light passing through the scanning mirror 1 and the target incident window 2. In one illustrative embodiment, the front lens group 3 adopts a fully refractive multi-lens combination architecture, which consists of three thick meniscus negative lenses, two sets of cemented doublet lenses (positive power and negative power), one positive power meniscus lens, and one positive power biconvex lens 37 arranged coaxially in the direction of beam propagation.

[0031] The first thick meniscus negative lens 31 of the three thick meniscus negative lenses adopts a thick meniscus negative lens structure with negative optical power. Its function is to initially receive the diverging light from the target, expand the system's field of view, and guide the beam to subsequent lenses. Preferably, the object-side radius of curvature of the first thick meniscus negative lens 31 is 16mm, the image-side radius of curvature is 6mm, and the lens thickness is 12mm. In terms of material, low-dispersion optical glass is preferred.

[0032] The advantages of a thick meniscus structure are: compared to thin lenses, it is easier to balance the beam deflection angle at the edge of the field of view by adjusting the lens thickness, thus avoiding beam overflow in a large field of view; the negative optical power characteristic can moderately flatten the diverging light rays of the target, reserving optical margin for the subsequent converging imaging of a positive optical power lens; at the same time, through the precise design of the curved profile, spherical aberration is initially suppressed, and optical simulation shows that it meets the system requirements for imaging spectrum. The lens surface is treated with a multi-layer anti-reflection coating, covering the coating band from 400nm to 1000nm, increasing the transmittance to over 96%, and reducing light loss and stray light caused by surface reflection.

[0033] The second thick meniscus negative lens 32, one of the three thick meniscus negative lenses, is located behind the first thick meniscus negative lens 31. However, it adopts a reverse curvature design, meaning that the direction of its curved surface convexity is opposite to that of the first thick meniscus negative lens 31. Its optical power is also negative. Its function is to counteract some of the aberrations generated by the first thick meniscus negative lens 31, such as coma and astigmatism, further optimizing the parallelism of the beam. Preferably, the second thick meniscus negative lens 32 has an object-side radius of curvature of -7mm (the negative sign indicates that the center of curvature is located on the image side, opposite to the direction of the center of curvature on the object side of the first thick meniscus negative lens 31), an image-side radius of curvature of -21mm, and a lens thickness of 9mm. It uses the same type of low-dispersion glass as the first thick meniscus negative lens 31.

[0034] The function of the reverse bending structure is to correct the deflection differences of the first thick meniscus negative lens 31 for beams at different field of view angles through the principle of reverse optical path compensation: the first thick meniscus negative lens 31 deflects the beam in the central field of view less and the beam in the edge field of view more, while the reverse bending of the second thick meniscus negative lens 32 can generate a reverse pulling force on the edge beam, making the beam propagation direction of different fields of view more uniform. The air gap between this lens and the first thick meniscus negative lens 31 is 5mm.

[0035] The third thick meniscus negative lens 33 is located behind the second thick meniscus negative lens 32. The third thick meniscus negative lens 33 shares the same curvature trend as the first thick meniscus negative lens 31 and remains a thick meniscus negative lens with negative optical power. Its function is to further expand the field of view coverage and to supplement and optimize the residual aberrations of the first two lenses, ensuring that the beam entering the subsequent cemented doublet has uniform propagation characteristics. The object-side radius of curvature of the third thick meniscus negative lens 33 is 10 mm, close to the 16 mm object-side radius of curvature of the first thick meniscus negative lens 31, and their curvature trends are consistent. The image-side radius of curvature is 8 mm, and the lens thickness is 3 mm.

[0036] The third thick meniscus negative lens 33, by adjusting the radius of curvature of its surface, can increase the system's field of view from 8° when using the first thick meniscus negative lens 31 alone to 12°. Simultaneously, its 3mm thinner design, compared to the 12mm of the first thick meniscus negative lens 31 and the 9mm of the second thick meniscus negative lens 32, reduces lens volume, meeting miniaturization requirements. Furthermore, the thin structure reduces stress deformation caused by the lens's own weight. The air gap between it and the second thick meniscus negative lens 32 is 0.3mm, a close-fitting arrangement that shortens the overall length of the lens assembly, further reducing its size.

[0037] The positive optical power cemented doublet 34 is located behind the third lens. After the field of view is controlled and preliminary aberration correction is performed by the three negative lenses, the light beam enters the positive optical power cemented doublet 34. This lens is made of two pieces of optical glass with different dispersion characteristics cemented together. It has a positive optical power, which enables the initial convergence of the light beam and specifically corrects chromatic aberration within a wide wavelength range. Preferably, the positive optical power cemented doublet 34 has an object-side radius of curvature of 7 mm, an image-side radius of curvature of -6 mm, and a total lens thickness of 4 mm. The two pieces of glass are low-refractive-index, high Abbe constant glass. Through the complementary dispersion characteristics of the two types of glass, the differences in the propagation speed of light of different wavelengths within a wide wavelength range are offset.

[0038] Optionally, an aperture stop 35 is further provided behind the positive power cemented doublet lens 34. Specifically, the aperture stop 35 is located between the positive power cemented doublet lens 34 and the subsequent negative power cemented doublet lens 36, and is a built-in aperture stop. Preferably, this aperture stop is a standard circular aperture stop, with the aperture stop plane perpendicular to the optical axis, an aperture stop thickness of 2.5 mm, and an actual entrance pupil diameter of 5 mm.

[0039] The aperture stop 35 is located between the two sets of cemented doublet lenses, which can ensure that it can effectively block stray light generated by the preceding lens, which mostly overflows from the lens edge and can be directly blocked by the aperture stop, without obstructing the beam reception of the subsequent lens.

[0040] The negative power cemented doublet 36 is located behind the aperture stop 35 and forms a positive and negative power combination with the positive power cemented doublet 34. It is used to balance the converging ability of the preceding positive power lens, adjust the divergence angle of the beam, so that the subsequent lens can receive the beam more efficiently, and at the same time supplement and correct residual chromatic aberration and spherical aberration.

[0041] The design logic of the positive and negative cemented doublet combination is as follows: While the positive optical power cemented doublet lens 34 can correct most chromatic aberration, it causes the beam to converge too strongly, requiring subsequent lenses to have a larger aperture to receive it; while the negative optical power cemented doublet lens 36 can appropriately diverge the converged beam, reducing the aperture requirement of subsequent lenses and adapting to miniaturized designs; at the same time, the negative optical power characteristic can counteract the spherical aberration generated by the positive optical power lens. The air gap between this lens and the aperture stop 35 is 0.3mm, ensuring that stray light intercepted by the aperture stop does not enter the lens, thus avoiding affecting image quality.

[0042] The positive power meniscus lens 34 is located behind the negative cemented doublet lens 36. After chromatic aberration and spherical aberration correction by the two sets of cemented doublet lenses, the light beam enters the positive power meniscus lens. This lens has a meniscus structure and positive power. Its function is to refocus the diverging light beam, optimize the parallelism of the beam, prepare for the final imaging by the biconvex lens, and further suppress astigmatism at the edge of the field of view. Preferably, the positive power meniscus lens has a radius of curvature of 11 mm, an image-side radius of curvature of 4 mm, and a lens thickness of 4 mm.

[0043] The advantage of the meniscus structure lies in its low astigmatism imaging. Compared to a biconvex lens, the curved profile of the meniscus lens better matches the beam propagation trajectory, reducing the number of reflections on the lens surface and lowering the probability of astigmatism. Simultaneously, its positive optical power characteristic can refocus the diverging beam from the negative cemented doublet, making the principal ray propagation direction closer to parallel, providing stable conditions for accurate imaging by the subsequent biconvex lens. Furthermore, the air gap between this lens and the negative cemented doublet is only 0.3 mm, a compact arrangement that further shortens the overall lens group length.

[0044] The positive optical power biconvex lens 37 is located at the end of the front objective lens group. The positive optical power biconvex lens 37 adopts a positive optical power biconvex lens 37 structure and has a positive optical power. It is used to finally converge the light beams processed by all the lenses in front to form a clear and stable primary image on the primary image plane where the slit assembly is located.

[0045] Preferably, the negative power cemented doublet lens 36 is made of two pieces of optical glass with different dispersion characteristics bonded together, with an object-side radius of curvature of -15mm, a cemented surface radius of curvature of 13mm, an image-side radius of curvature of -9mm, and a total lens thickness of 1mm; the positive power meniscus lens has an object-side radius of curvature of 11mm, an image-side radius of curvature of 4mm, and a lens thickness of 4mm; the positive power biconvex lens 37 has an object-side radius of curvature of 6mm, an image-side radius of curvature of 7mm, and a lens thickness of 5mm, and is made of fused silica glass.

[0046] The design focus of a biconvex lens is on controlling the image plane accuracy. A symmetrical biconvex structure ensures uniform refraction of the light beam across both lens surfaces, reducing image distortion caused by surface asymmetry. The air gap between the positive power biconvex lens 37 and the front meniscus lens is 3mm. Fine-tuning this gap allows for further optimization of the image plane position, ensuring sharp imaging.

[0047] The front mirror assembly 3 is located behind the target entrance window 2, and its optical axis is aligned with the center of the scanning mirror 1 and the target entrance window 2. After passing through the mirror assembly, the light converges onto the primary image plane. The front mirror assembly 3 is fixed to the mirror barrel by a threaded interface or adhesive bonding and is coupled to the slit assembly 4.

[0048] The slit assembly 4 is positioned at the primary image plane. Schematic, the slit is made of ultra-precision machined stainless steel, Invar, or glass sheet, with polished or coated edges. Its function is to encode the spatial information of the target image into a linear beam, facilitating subsequent beam splitting.

[0049] The slit assembly 4 is positioned close to the image plane of the front lens group 3 and directly docks with the collimating lens group 5.

[0050] The collimating lens group 5 is used to collimate the light rays passing through the slit, converting the diverging beam into parallel light. This lens group is designed symmetrically to and matches the collecting lens group 7, and consists of the same set of collimating lenses, including double or triple lenses, to minimize aberrations. It is located behind the slit assembly 4, with its incident surface coinciding with the slit image plane. After collimation, the light rays become parallel beams and directly incident on the grating and wedge plate assembly 6. The collimating lens group 5 is connected to the slit assembly 4 and the grating assembly via an optical support (not shown in the figure).

[0051] The grating and wedge plate assembly 6 constitutes the spectral processing section of the device. The grating utilizes the principle of diffraction to disperse incident parallel light according to wavelength, while the wedge plate is used to correct the optical path or compensate for chromatic aberration. The grating is preferably a transmission grating. The grating and wedge plate assembly 6 is positioned between the collimating lens group 5 and the collecting lens group 7. After collimation, the light is incident on the grating surface, split into different wavelengths, and then guided to the collecting lens group 7 through the wedge plate. The grating and wedge plate assembly 6 is mounted via a rotating bracket or adjustment platform (not shown in the figure). The interfaces with the front and rear lens groups are sealed to prevent environmental interference.

[0052] The collecting mirror group 7 is used for secondary imaging of the dispersed light beam, converging the scattered spectral beam onto the detector. This mirror group adopts a symmetrical design with the collimating mirror group 5, consisting of multiple lenses to correct aberrations introduced by spectral dispersion, such as field curvature and distortion, ensuring a clear spectral image. The collecting mirror group 7 is located behind the grating and wedge plate assembly 6, with its optical axis aligned with the grating diffraction direction, converging the light onto the secondary image plane. The collecting mirror group 7 is connected to the detector assembly via a mirror tube.

[0053] Optionally, a detector assembly (not shown) is also included after the collecting mirror group 7. The detector assembly is the terminal part of the device and is used to acquire the hyperspectral data cube.

[0054] The detector chip is preferably a CMOS or CCD sensor, located adjacent to the image plane of the collecting mirror group 7, and connected to the optomechanical device via a standardized interface (such as a C-interface or an F-interface). Preferably, the detector assembly is fixed by a data cable and a mechanical base.

[0055] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0056] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A spectroscopic camera with a fully refractive front mirror assembly, characterized in that, The system includes a front mirror assembly (3), a slit assembly (4), a collimating mirror assembly (5), a grating and wedge plate assembly (6), a collecting mirror assembly (7), and a detector assembly arranged sequentially along the optical axis. The scanning mirror (1) is located at the front of the camera. The target entrance window (2) is located immediately behind the scanning mirror (1) and is directly connected to the front mirror assembly (3). The front mirror assembly (3) is a fully refractive multi-lens assembly and is coupled to the slit assembly (4). The slit assembly (4) is located at the primary image plane. The collimating mirror assembly (5) is located behind the slit assembly (4). The grating and wedge plate assembly (6) is located between the collimating mirror assembly (5) and the collecting mirror assembly (7). The collecting mirror assembly (7) is located behind the grating and wedge plate assembly (6), and the detector assembly is located behind the collecting mirror assembly (7).

2. The spectroscopic camera with a fully refractive front mirror group according to claim 1, characterized in that, The front lens group (3) includes, in sequence according to the beam propagation direction, a first thick meniscus negative lens (31), a second thick meniscus negative lens (32), a third thick meniscus negative lens (33), a positive power cemented doublet lens (34), a negative power cemented doublet lens (36), a positive power meniscus lens, and a positive power biconvex lens (37), with each lens arranged coaxially.

3. The spectroscopic camera with a fully refractive front mirror group according to claim 2, characterized in that, The first thick meniscus negative lens (31) has an object side curvature radius of 16mm, an image side curvature radius of 6mm, and a lens thickness of 12mm.

4. The spectroscopic camera with a fully refractive front mirror group according to claim 3, characterized in that, The second thick meniscus negative lens (32) has an object side curvature radius of -7mm, an image side curvature radius of -21mm, and a lens thickness of 9mm.

5. The spectroscopic camera with a fully refractive front mirror group according to claim 4, characterized in that, The third thick meniscus negative lens (33) has an object side curvature radius of 10 mm, an image side curvature radius of 8 mm, and a lens thickness of 3 mm.

6. The spectroscopic camera with a fully refractive front mirror group according to claim 5, characterized in that, The positive power cemented doublet (34) has an object side curvature radius of 7 mm, an image side curvature radius of -6 mm, and a total lens thickness of 4 mm. An aperture stop (35) is provided between the positive power cemented doublet (34) and the negative power cemented doublet (36). The aperture stop (35) is a standard circular aperture stop, and the aperture stop plane is perpendicular to the optical axis.

7. The spectroscopic camera with a fully refractive front mirror group according to claim 6, characterized in that, The negative power cemented doublet lens (36) has a lens thickness of 1 mm; the positive power meniscus lens has an image-side radius of curvature of 4 mm and a lens thickness of 4 mm; the positive power biconvex lens (37) has an object-side radius of curvature of 6 mm, an image-side radius of curvature of 7 mm, and a lens thickness of 5 mm.

8. The spectroscopic camera with a fully refractive front mirror group according to claim 7, characterized in that, The edge of the slit assembly (4) is polished or coated; the slit assembly (4) is adjacent to the image plane of the front lens group (3) and directly docks with the collimating lens group (5).

9. The spectroscopic camera with a fully refractive front mirror group according to claim 8, characterized in that, The collimating lens group (5) and the collecting lens group (7) are symmetrical structures, both consisting of double or triple lenses; the incident surface of the collimating lens group (5) coincides with the slit image plane.

10. The spectroscopic camera with a fully refractive front mirror group according to claim 9, characterized in that, The grating in the grating and wedge plate assembly (6) is a transmission grating. The grating and wedge plate assembly (6) is installed by a rotating bracket or adjustment platform, and the interface with the front and rear mirror groups adopts a sealed design. The chip of the detector assembly is a CMOS or CCD sensor, which is connected to the camera body through a C interface or an F interface.

Images