CN219142017U

CN219142017U - Snapshot prism type spectroscopic imaging system

Info

Publication number: CN219142017U
Application number: CN202223291194.4U
Authority: CN
Inventors: 赵世家; 季轶群; 谭奋利
Original assignee: Suzhou University
Current assignee: Suzhou University
Priority date: 2022-12-08
Filing date: 2022-12-08
Publication date: 2023-06-06
Anticipated expiration: 2032-12-08

Abstract

The utility model relates to a snapshot prism type spectroscopic imaging system, which is of a concentric foldback common light path structure, and sequentially comprises the following components according to the incident direction of light: the lens comprises a plano-concave lens, a biconvex lens, a meniscus lens bent in the light incidence direction, a first curved surface prism bent in the light incidence direction, a second curved surface prism bent in the light incidence direction and a spherical reflector bent in the light incidence direction; the aperture diaphragm of the system is arranged on the spherical reflecting mirror; the two curved prisms are made of different glass materials, and the vertex angles are opposite to form a biprism beam splitting structure. According to the light-splitting imaging system provided by the utility model, light rays pass through the light-splitting element formed by the two curved prisms twice, so that the light rays can be split and imaged at the same time, and the light energy utilization rate of the system is effectively improved; meanwhile, the common light path structure is adopted, so that the light splitting capacity of the system is further improved, the spectrum resolution is increased, the volume of the system is effectively restrained, and the system has the characteristics of large aperture, high spectrum resolution, high light energy utilization rate, small volume and the like.

Description

Snapshot prism type spectroscopic imaging system

Technical Field

The utility model relates to a spectroscopic imaging system of an imaging spectrometer, in particular to a prism-type spectroscopic imaging system for a snapshot-type spectroscopic imaging system.

Background

The snapshot hyperspectral imager has the advantages of high spectrum reconstruction efficiency, wide working wavelength, high spectrum resolution and the like, is widely applied to astronomical and remote sensing fields, and is continuously expanded to other fields. The integral view field type snapshot hyperspectral imager is used as one of the snapshot hyperspectral imagers, two-dimensional image information is divided and rearranged and dispersed through the hyperspectral imager, and two-dimensional image information and one-dimensional spectrum information of an observation target can be obtained at the same time, so that non-scanning hyperspectral imaging data acquisition is realized.

The spectral element is used as a core part of the snapshot imaging spectrometer, determines the imaging performance and the spectral resolution of the system, and the numerical aperture, the light energy utilization rate and the imaging field of view of the snapshot spectral imaging system reported in the prior literature are usually smaller. See document "Microlens array snapshot hyperspectral microscopy system for the biomedical domain" (Applied Optics, vol.60, no.7, 2021), which reports a transmission type snapshot hyperspectral imaging system based on prism-grating combined light splitting, wherein the system adopts a grating and a prism to realize light splitting, and the system has the defects of low light energy utilization rate, spectrum cascade and the like; the collimating part and the refocusing part of the system adopt double Gaussian structure design, the quantity of introduced lenses is large, the design structure is complex, the difficulty is large, and the large numerical aperture is difficult to realize.

Disclosure of Invention

Aiming at the defects of the prior art, the utility model provides a snapshot prism type spectral imaging system with wide wave band, large aperture, high spectral resolution and compact structure.

The technical scheme adopted by the utility model is to provide a snapshot prism type spectroscopic imaging system which is of a concentric foldback common light path structure, and the snapshot prism type spectroscopic imaging system sequentially comprises the following components according to the incident direction of light: the lens comprises a plano-concave lens, a biconvex lens, a meniscus lens bent in the light incidence direction, a first curved surface prism bent in the light incidence direction, a second curved surface prism bent in the light incidence direction and a spherical reflector bent in the light incidence direction; the aperture diaphragm of the system is arranged on the spherical reflecting mirror;

the vertex angles of the first curved prism and the second curved prism are arranged oppositely, and air is separated to form a biprism beam splitting structure; the refractive index of the material of the first curved prism and the second curved prism is n in turn ₅ And n ₆ Abbe number v in order ₅ And v ₆ The conditions are satisfied: n is more than or equal to 1.72 ₅ ≤1.79，1.67≤n ₆ ≤1.74；50≤v ₅ Not less than 55 and not more than 27 v ₆ ≤32；

The rear surface of the plano-concave lens, the front and rear surfaces of the biconvex lens, the meniscus lens, the first curved prism and the second curved prism are spherical surfaces, and the curvature radiuses of the biconvex lens, the meniscus lens, the first curved prism and the second curved prism are R in sequence ₂₂ 、R ₃₁ 、R ₃₂ 、R ₄₁ 、R ₄₂ 、R ₅₁ 、R ₅₂ 、R ₆₁ 、R ₆₂ The conditions are satisfied with mm as a length unit: 175 is less than or equal to R ₂₂ ≤180、1240≤R ₃₁ ≤1245、-45≤R ₃₂ ≤-40、-70≤R ₄₁ ≤-65、-77≤R ₄₂ ≤-73、-105≤R ₅₁ ≤-100、-105≤R ₅₂ ≤-100、-102≤R ₆₁ ≤-98、-136≤R ₆₂ ≤-132。

The utility model provides a snapshot prism type spectroscopic imaging system, wherein the numerical aperture NA of an object is more than or equal to 0.21 and less than or equal to 0.25, and the length L of a barrel is more than or equal to 150mm and less than or equal to 180mm.

The snapshot prism type spectroscopic imaging system provided by the utility model has the characteristics of concentric foldback common light path, the vertex angles of the two curved prisms are oppositely arranged, meanwhile, light rays are split and imaged, the light energy utilization rate of the system is improved, and the light collecting capacity of the system is effectively improved; meanwhile, the common light path structure further improves the light splitting capacity of the system and is compact in structure.

Compared with the prior art, the utility model has the beneficial effects that:

1. according to the light-splitting imaging system provided by the utility model, the light-splitting part of the system is formed by only two curved prisms made of different materials, so that the light energy utilization rate and the light-splitting capacity of the system can be effectively improved, the length TOTR of an optical cylinder of the system is less than 170mm, and the light-splitting imaging system has the characteristics of compact structure, easiness in tooling adjustment and high stability.

2. The utility model adopts a concentric foldback common light path structure and a curved prism group structure, the light splitting system has the characteristics of large numerical aperture, high incident light flux and high system optical efficiency, and the surface surfaces of the three lenses and the two curved prisms are spherical surfaces, so that the lens processing difficulty and cost are reduced, the structure is compact, the installation and adjustment are easy, and the practical application value is realized.

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 plano-concave lens; 3. a biconvex lens; 4. a meniscus lens; 5. a first curved prism; 6. a second curved prism; 7. a spherical mirror; 8. an image plane;

FIG. 2 is a ray trace point column of a spectroscopic imaging system according to an embodiment of the present utility model;

FIG. 3 is a graph of the transfer function MTF of a spectroscopic imaging system according to an embodiment of the present utility model;

FIG. 4 is a plot of the in-turn energy concentration of a spectroscopic imaging system in accordance with an embodiment of the present utility model.

Detailed Description

The technical scheme of the utility model is further described below with reference to the accompanying drawings and examples.

Example 1:

the present embodiment provides a prismatic spectroscopic imaging system for snapshot spectroscopic imaging. According to the incidence direction of light rays, the optical lens comprises a plano-concave lens, a biconvex lens, a meniscus lens, two curved prisms and a spherical reflector in sequence, wherein the numerical aperture NA of an object space is 0.23, the view field of the object space is 6 multiplied by 3.5mm, and the working wave band is 400-700 nm.

Referring to fig. 1, it is a schematic structural diagram of a spectroscopic imaging system provided in this embodiment, in which an object plane 1 and an image plane 8 are located on the same side in space, and optical elements are, in order according to a light incident direction, a plano-concave lens 2, a biconvex lens 3, a meniscus lens 4, a first curved prism 5, a second curved prism 6, and a spherical mirror 7; wherein, the meniscus lens 4 is bent to the light incidence direction, the first curved prism 5 is bent to the light incidence direction, the second curved prism 6 is bent to the light incidence direction, and the spherical reflector 7 is bent to the light incidence direction.

In this embodiment, the first curved prism 5 and the second curved prism 6 are disposed opposite to each other at the top angle, and the two curved prisms are separated from each other and have an air gap to form a biprism beam-splitting structure; the refractive index of the material of the first curved prism and the second curved prism is n in turn ₅ And n ₆ Abbe number v in order ₅ And v ₆ The conditions are satisfied: n is more than or equal to 1.72 ₅ ≤1.79，1.67≤n ₆ ≤1.74；50≤v ₅ Not less than 55 and not more than 27 v ₆ ≤32；

The rear surface of the plano-concave lens 2, the front and rear surfaces of the biconvex lens 3, the meniscus lens 4, the first curved prism 5 and the second curved prism 6 are spherical surfaces, and the curvature radius is R in turn ₂₂ 、R ₃₁ 、R ₃₂ 、R ₄₁ 、R ₄₂ 、R ₅₁ 、R ₅₂ 、R ₆₁ 、R ₆₂ The conditions are satisfied with mm as a length unit: 175 is less than or equal to R ₂₂ ≤180、1240≤R ₃₁ ≤1245、-45≤R ₃₂ ≤-40、-70≤R ₄₁ ≤-65、-77≤R ₄₂ ≤-73、-105≤R ₅₁ ≤-100、-105≤R ₅₂ ≤-100、-102≤R ₆₁ ≤-98、-136≤R ₆₂ ≤-132。

The range of the numerical aperture NA of the object space of the prism type spectroscopic imaging system provided by the embodiment can be more than or equal to 0.21 and less than or equal to 0.25, and the range of the barrel length L is more than or equal to 150mm and less than or equal to 180mm.

When the spectral imaging system images, the emergent compound-color light rays at the object plane are incident to the plano-concave lens, the large-aperture light rays are incident to the biconvex lens and the meniscus lens, the light rays are converged and then are incident to the first curved surface prism and the second curved surface prism, the compound-color divergent light rays are divided into monochromatic converging light rays with different wavelengths through the two curved surface prisms and are incident to the spherical reflector, and the light rays are converged and reflected and emergent; the monochromatic convergent light rays with different wavelengths are incident to the second curved prism, the first curved prism, the meniscus lens, the biconvex lens and the plano-concave lens again, and the monochromatic convergent light rays are focused and imaged on an image surface to complete the imaging process.

The parameters of each optical element in 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 is that the root mean square radius of the point diagram of each view field corresponding to three wavelengths of 400nm, 550nm and 700nm in the diagram is smaller than 2.60 μm, the geometric radius of the point diagram is smaller than 10.50 μm, and the imaging quality is good.

Referring to fig. 3, it is a transfer function MTF curve on the image plane corresponding to each field of view of the spectroscopic imaging system provided in this embodiment. As can be seen from fig. 3, at 100lp/mm, the MTF values of the fields of view with wavelengths of 400nm (a graph), 550nm (b graph) and 700nm (c graph) are all greater than 0.3, the curves are relatively smooth and approximate to the diffraction limit, which indicates that the lens imaging is clear and uniform, and the system has good imaging quality in the full-band full-view field.

Referring to fig. 4, it is a graph of the energy concentration of 700nm wavelength of the spectral imaging system provided in this embodiment, and as can be seen from fig. 4, more than 70% of the energy is concentrated in the Airy spot range, and the energy is more concentrated.

The snapshot type spectral imaging system provided by the technical scheme of the utility model consists of a plano-concave lens, a biconvex lens, a meniscus lens, two curved prisms and a spherical reflecting mirror, wherein the curved prisms have imaging and light splitting capabilities, and through reasonable selection of glass materials of the two curved prisms, the numerical aperture of lens imaging is improved, the light energy utilization rate of the system is improved, and an optical image with high energy concentration and high spectral resolution is obtained. The spectral imaging system provided by the technical scheme of the utility model has the characteristics of large numerical aperture, good imaging quality, high light energy utilization rate, high spectral resolution and the like after strict aberration correction, has the advantages of compact system structure, strong stability and the like, is suitable for the field of spectral imaging, and has wide application prospect.

Claims

1. A snapshot prism-type spectroscopic imaging system, characterized in that: the coaxial-folded common-path structure is characterized in that the coaxial-folded common-path structure sequentially comprises the following components in the incident direction of light: a plano-concave lens (2), a biconvex lens (3), a meniscus lens (4) bent in the direction of light incidence, a first curved prism (5) bent in the direction of light incidence, a second curved prism (6) bent in the direction of light incidence, a spherical mirror (7) bent in the direction of light incidence; the aperture diaphragm of the system is arranged on the spherical reflecting mirror (7);

the vertex angles of the first curved prism (5) and the second curved prism (6) are arranged oppositely, and air is separated to form a biprism beam splitting structure; the refractive index of the materials of the first curved prism (5) and the second curved prism (6) is n in turn ₅ And n ₆ Abbe number v in order ₅ And v ₆ The conditions are satisfied: n is more than or equal to 1.72 ₅ ≤1.79，1.67≤n ₆ ≤1.74；50≤v ₅ Not less than 55 and not more than 27 v ₆ ≤32；

The rear surface of the plano-concave lens (2), the front and rear surfaces of the biconvex lens (3), the meniscus lens (4), the first curved prism (5) and the second curved prism (6) are spherical surfaces, and the curvature radiuses of the surfaces are R in sequence ₂₂ 、R ₃₁ 、R ₃₂ 、R ₄₁ 、R ₄₂ 、R ₅₁ 、R ₅₂ 、R ₆₁ 、R ₆₂ The conditions are satisfied with mm as a length unit: 175 is less than or equal to R ₂₂ ≤180、1240≤R ₃₁ ≤1245、-45≤R ₃₂ ≤-40、-70≤R ₄₁ ≤-65、-77≤R ₄₂ ≤-73、-105≤R ₅₁ ≤-100、-105≤R ₅₂ ≤-100、-102≤R ₆₁ ≤-98、-136≤R ₆₂ ≤-132。

2. A snapshot prism-type spectroscopic imaging system according to claim 1, wherein: the numerical aperture NA of the object space is in the range of 0.21-0.25, and the length L of the cylinder is in the range of 150-180 mm.