CN219455309U - Spectral imaging system suitable for snapshot imaging spectrometer - Google Patents
Spectral imaging system suitable for snapshot imaging spectrometer Download PDFInfo
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- CN219455309U CN219455309U CN202223291388.4U CN202223291388U CN219455309U CN 219455309 U CN219455309 U CN 219455309U CN 202223291388 U CN202223291388 U CN 202223291388U CN 219455309 U CN219455309 U CN 219455309U
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Abstract
The utility model relates to a spectroscopic imaging system suitable for a snapshot imaging spectrometer. The object plane and the image plane of the spectral imaging system are positioned on the same side in space; the optical elements are coaxial, common-path and approximate concentric structures, and according to the incident direction of light rays, the optical elements are sequentially as follows: the front surface is a plane hemispherical lens, a first piece of curved surface prism which is bent to the light incidence direction, a second piece of curved surface prism which is bent to the light incidence direction, and a spherical reflector which is bent to the light incidence direction; the aperture diaphragm of the system is arranged on the spherical reflecting mirror; the rear surface of the first curved prism and the front surface of the second curved prism are glued with each other, and the vertex angles of the two prisms are arranged oppositely to form a double-prism light-splitting structure. The spectral imaging system provided by the utility model has a common light path structure, can effectively improve the chromatic dispersion capability of the system, and has the characteristics of high fidelity, large view field, high spectral resolution, high light energy utilization rate, compact structure and the like.
Description
Technical Field
The utility model relates to a spectroscopic imaging system of an imaging spectrometer, in particular to a snapshot spectroscopic imaging system.
Background
The spectral element is used as a core part of the snapshot imaging spectrometer, and determines the imaging performance and the spectral resolution of the system. In the prior art, the common light splitting elements comprise gratings, prisms, optical filters and the like, the serious spectrum stacking problem exists in the light splitting of the gratings, and the working wave band and the view field of the system are limited; the spectral resolution of the filter spectral imaging spectrometer is low. See document "Microlens array snapshot hyperspectral microscopy system for the biomedical domain" (Applied Optics, vol.60, no.7, 2021), which reports a transmission snapshot hyperspectral imaging system based on prism-grating combination spectroscopy, by a complex design of a double gaussian initial structure, using a collimating part of a six-piece spherical lens composition system and a refocusing part of a six-piece spherical lens composition system in total, to achieve visible light band and hyperspectral imaging; but the system suffers from the following disadvantages: the system adopts the prism and the plane grating to realize light splitting, has low light energy utilization rate, has the problem of spectrum overlapping, and introduces serious spectrum distortion to influence the spatial resolution and the spectrum resolution of the system; the collimating part and the refocusing part of the system adopt a double Gaussian structure design, the quantity of introduced lenses is large, the design difficulty is high, and a large numerical aperture is difficult to realize.
Disclosure of Invention
Aiming at the defects of the prior art, the utility model provides a snapshot type spectroscopic imaging system which has the advantages of large field of view, high spectral resolution, good imaging quality, simple and compact structure and easy tooling adjustment.
The technical scheme for realizing the aim of the utility model is as follows: providing a large-view-field high-fidelity snapshot type spectroscopic imaging system, wherein an object plane and an image plane of the spectroscopic imaging system are positioned on the same side in space; the optical elements are coaxial, common-path and approximate concentric structures, and according to the incident direction of light rays, the optical elements are sequentially as follows: the front surface is a plane hemispherical lens, a first piece of curved surface prism which is bent to the light incidence direction, a second piece of curved surface prism which is bent to the light incidence direction, and a spherical reflector which is bent to the light incidence direction; the aperture diaphragm of the system is arranged on the spherical reflecting mirror; the rear surface of the first curved prism and the front surface of the second curved prism are glued with each other, and the vertex angles of the two prisms are arranged oppositely to form a double-prism light-splitting structure.
The hemispherical lens, the first curved prism and the second curved prism are spherical refraction lenses; the back surface of the hemispherical lens, the front surface and the back surface of the first curved prism and the back surface of the second curved prism, and the curvature radius of the hemispherical lens and the back surface of the first curved prism are R in sequence 22 、R 31 、R 32 、R 42 The conditions are satisfied with mm as a length unit: 57 is less than or equal to R 22 ≤63、163≤R 31 ≤168、183≤R 32 ≤188、200≤R 42 And is less than or equal to 206. The refractive index of the first curved prism is n 3 Abbe number v 3 The conditions are satisfied: n is more than or equal to 1.70 3 Less than or equal to 1.85; the refractive index of the second curved prism is n 4 Abbe number v 4 The conditions are satisfied: n is more than or equal to 1.85 4 ≤1.97，20≤v 4 ≤23。
The utility model provides a large-view-field high-fidelity snapshot type spectroscopic imaging system, wherein the numerical aperture NA of an object space is in a value range of 0.17-0.22, and the length L of a cylinder is in a range of 250-310 mm.
The snapshot type spectroscopic imaging system provided by the utility model adopts a coaxial and concentric design, so that the correction capability of the spectral distortion of the system can be effectively improved; the vertex angles of the two curved prisms are oppositely arranged, the rear surface of the first curved prism and the front surface of the second curved prism are glued with each other, meanwhile, light is split and imaged, the light energy utilization rate of the system is improved, the view field of the system is increased, and the light collecting capacity of the system is effectively improved; the two prisms are made of different glass materials, the first curved prism is made of a material with a low refractive index and a high Abbe number, the second curved prism is made of a material with a high refractive index and a low Abbe number, the spectral distortion of the system is small, and the spectral imaging with a large view field and high fidelity can be realized; meanwhile, the system adopts a common light path structure, improves the light splitting capacity of the system, and has a compact structure.
Compared with the prior art, the utility model has the beneficial effects that:
1. the beam-splitting imaging system provided by the utility model only uses two curved prisms made of different materials to form a beam-splitting part of the system, adopts a coaxial concentric common-light path structure, improves the light energy utilization rate and the beam-splitting capability of the system, and has the characteristics of compact structure, easiness in tooling adjustment and strong stability.
2. The utility model combines the advantages of a concentric optical system and a curved prism, has large numerical aperture, large view field and high incident light flux, and the surface types of the three refractive lenses and the two curved prisms are spherical, so that the lens processing difficulty and cost are reduced, the structure is compact, the installation and adjustment are easy, and the utility model has practical application value.
Drawings
Fig. 1 is a schematic structural diagram of a spectroscopic imaging system according to an embodiment of the present utility model;
in the figure, 1. Object plane; 2. a hemispherical lens; 22. a rear surface of the hemispherical lens; 3. a first curved prism; 31. a front surface of the first curved prism; 32. a rear surface of the first sheet of curved prisms (a front surface of the second sheet of curved prisms); 4. a second curved prism; 42. the rear surface of the second curved prism; 5. a spherical mirror; 6. an image plane;
FIG. 2 is a ray trace point column diagram of a spectroscopic imaging system provided by an embodiment of the present utility model;
FIG. 3 is a graph of the transfer function MTF of a spectroscopic imaging system provided by an embodiment of the present utility model;
FIG. 4 is a plot of the in-turn energy concentration of a spectroscopic imaging system provided by an embodiment of the present utility model.
Detailed description of the preferred embodiments
The technical scheme of the utility model is further described below with reference to the accompanying drawings and examples.
Example 1:
the embodiment provides a large-view-field high-fidelity snapshot type spectroscopic imaging system, wherein the numerical aperture NA of an object space is 0.20, the view field of the object space is 28 multiplied by 8mm, and the working wave band is 400-760 nm.
Referring to fig. 1, a schematic structural diagram of a spectroscopic imaging system provided in this embodiment is provided, where the spectroscopic imaging system is formed by a hemispherical lens, two curved prisms and a spherical mirror, and the spectroscopic imaging system is a coaxial, common-path, and approximately concentric structure, where an object plane 1 and an image plane 6 are located on the same side in space, and optical elements are, in order according to a light incident direction, a hemispherical lens 2, a first curved prism 3, a second curved prism 4 and a spherical mirror 5; wherein, the front surface of the hemispherical lens 2 is a plane, the first curved prism 3 is bent to the light incidence direction, the second curved prism 4 is bent to the light incidence direction, and the spherical reflector 5 is bent to the light incidence direction. The rear surface of the first curved prism and the front surface of the second curved prism are glued with each other, and the vertex angles of the two prisms are arranged oppositely to form a double-prism light-splitting structure.
In the present embodiment, the hemispherical lens 2, the first curved prism 3 and the second curved prism 4 are spherical refractive lenses, and the rear surface 22 of the hemispherical lens, the front surface 31 and the rear surface (the front surface of the second curved prism) 32 of the first curved prism 3 and the rear surface 42 of the second curved prism 4 have the radii of curvature of R in this order in the light incidence direction 22 、R 31 、R 32 、R 42 The conditions are satisfied with mm as a length unit: 57 is less than or equal to R 22 ≤63、163≤R 31 ≤168、183≤R 32 ≤188、200≤R 42 ≤206。
The refractive index of the first curved prism 3 is n 3 Abbe number v 3 The conditions are satisfied: n is more than or equal to 1.70 3 The refractive index of the second piece of curved prism 4 is less than or equal to 1.85 and is n 4 Abbe number v 4 The conditions are satisfied: n is more than or equal to 1.85 4 ≤1.97，20≤v 4 ≤23。
When the spectral imaging system provided by the embodiment works, the compound color light rays emitted from the object plane are incident to the hemispherical lens, the large-aperture light rays are converged and then are incident to the first curved surface prism and the second curved surface prism, after being split by the two curved surface prisms, the single-color converging light rays with different wavelengths are incident to the spherical reflecting mirror, the light rays are converged and reflected and emitted, the single-color converging light rays with different wavelengths are incident to the second curved surface prism, the first curved surface prism and the hemispherical lens again, and the light rays are focused and then imaged on the image plane to complete the imaging process.
The parameters of the optical elements of this example are shown in table 1.
Table 1:
。
referring to fig. 2, the optical beam trace point diagram of the optical beam splitting imaging system provided by the embodiment, in the diagram, the root mean square radius of the point diagram of each view field corresponding to three wavelengths of 400nm, 580nm and 760nm is smaller than 0.7 μm, the geometric radius of the point diagram is smaller than 2.20 μm, and the imaging quality is good.
Referring to fig. 3, it is a transfer function MTF graph on the image plane corresponding to each view field of the spectral imaging system provided in this embodiment, in fig. 3, a graph, b graph and c graph correspond to MTF graphs of each view field of wavelengths of 400nm, 580nm and 760nm at 145lp/mm, respectively, and as can be seen from fig. 3, the values of the MTF graphs are all greater than 0.7, approaching the diffraction limit, the curve is smoother, which indicates that the lens imaging is clear and uniform, and the system has good imaging quality in the full view field of the full band.
Referring to fig. 4, it is an energy concentration curve of 760nm wavelength of the spectroscopic imaging system provided in this embodiment, and as can be seen from fig. 4, more than 80% of energy is concentrated in the Airy spot range, and the energy is more concentrated.
The spectral imaging system provided by the technical scheme of the utility model has the characteristics of large numerical aperture, large visual field, good imaging quality, high spectral resolution, high light energy utilization rate, compact structure, easiness in tooling adjustment, strong stability and the like after strict aberration correction, and is suitable for the field of spectral imaging.
Claims (4)
1. A spectroscopic imaging system suitable for a snapshot imaging spectrometer, characterized in that: the object plane (1) and the image plane (6) of the spectral imaging system are positioned on the same side in space; the optical elements are coaxial, common-path and approximate concentric structures, and according to the incident direction of light rays, the optical elements are sequentially as follows: a hemispherical lens (2) with a plane front surface, a first curved prism (3) bent in the light incidence direction, a second curved prism (4) bent in the light incidence direction, and a spherical reflector (5) bent in the light incidence direction; the aperture diaphragm of the system is arranged on the spherical reflecting mirror (5); the rear surface of the first curved prism and the front surface of the second curved prism are glued with each other, and the vertex angles of the two prisms are arranged oppositely to form a double-prism light-splitting structure.
2. A spectroscopic imaging system adapted for use in a snapshot imaging spectrometer as recited in claim 1, wherein: the hemispherical lens (2), the first curved prism (3) and the second curved prism (4) are spherical refraction lenses; a rear surface (22) of the hemispherical lens, a front surface (31) and a rear surface (32) of the first curved prism (3), and a rear surface (42) of the second curved prism (4), which have a radius of curvature R in order 22 、R 31 、R 32 、R 42 The conditions are satisfied with mm as a length unit: 57 is less than or equal to R 22 ≤63、163≤R 31 ≤168、183≤R 32 ≤188、200≤R 42 ≤206。
3. A spectroscopic imaging system adapted for use in a snapshot imaging spectrometer as recited in claim 1, wherein: the refractive index of the first curved prism (3) is n 3 Abbe number v 3 The conditions are satisfied: n is more than or equal to 1.70 3 Less than or equal to 1.85; the refractive index of the second curved prism (4) is n 4 Abbe number v 4 The conditions are satisfied: n is more than or equal to 1.85 4 ≤1.97，20≤v 4 ≤23。
4. A spectroscopic imaging system adapted for use in a snapshot imaging spectrometer as recited in claim 1, wherein: the numerical aperture NA of the object space is in the range of 0.17-0.22, and the length L of the cylinder is in the range of 250-310 mm.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202223291388.4U CN219455309U (en) | 2022-12-08 | 2022-12-08 | Spectral imaging system suitable for snapshot imaging spectrometer |
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| CN202223291388.4U CN219455309U (en) | 2022-12-08 | 2022-12-08 | Spectral imaging system suitable for snapshot imaging spectrometer |
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| CN219455309U true CN219455309U (en) | 2023-08-01 |
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| CN202223291388.4U Active CN219455309U (en) | 2022-12-08 | 2022-12-08 | Spectral imaging system suitable for snapshot imaging spectrometer |
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