阅读说明：本技术 一种基于自由曲面棱镜的一体式微型光谱仪光学系统 (Integrated micro spectrometer optical system based on free-form surface prism ) 是由 王占山 余俊 沈正祥 王旭 于 2020-06-27 设计创作，主要内容包括：本发明涉及一种基于自由曲面棱镜的一体式微型光谱仪光学系统,包括入射狭缝(1)、自由曲面棱镜(2)和像面(3),所述的自由曲面棱镜(2)包括入瞳平面(201)、准直区域(202)、聚焦区域(204)和出射面(205),所述的准直区域(202)和聚焦区域(204)上设有反射镜,所述的自由曲面棱镜(2)上还设有平面衍射光栅(203),入射光线由入射狭缝(1)出射,经入瞳平面(201)入射后经准直区域(202)反射至平面衍射光栅(203),衍射分光后的光线经聚焦区域(204)反射并经出射面(205)出射,聚焦在像面(3)成像。与现有技术相比,本发明具有高性能、构型紧凑和低成本等优点。(The invention relates to an integrated micro spectrometer optical system based on a free-form surface prism, which comprises an incident slit (1), a free-form surface prism (2) and an image surface (3), wherein the free-form surface prism (2) comprises an entrance pupil plane (201), a collimation area (202), a focusing area (204) and an exit surface (205), reflectors are arranged on the collimation area (202) and the focusing area (204), a plane diffraction grating (203) is further arranged on the free-form surface prism (2), incident light rays exit from the incident slit (1), are reflected to the plane diffraction grating (203) through the collimation area (202) after entering through the entrance pupil plane (201), and are reflected through the focusing area (204) and exit through the exit surface (205), and are focused on the image surface (3) for imaging. Compared with the prior art, the invention has the advantages of high performance, compact configuration, low cost and the like.)

1. The integrated micro spectrometer optical system based on the free-form surface prism is characterized by comprising an incidence slit (1), a free-form surface prism (2) and an image surface (3), wherein the free-form surface prism (2) comprises an entrance pupil plane (201), a collimation area (202), a focusing area (204) and an exit surface (205), reflectors are arranged on the collimation area (202) and the focusing area (204), a plane diffraction grating (203) is further arranged on the free-form surface prism (2), incident light rays are emitted from the incidence slit (1), are reflected to the plane diffraction grating (203) through the collimation area (202) after being incident through the entrance pupil plane (201), and are reflected through the focusing area (204) and emitted through the exit surface (205) and focused on the image surface (3) for imaging.

2. The optical system of claim 1, wherein the entrance pupil plane (201) and the exit plane (205) are the same non-rotationally symmetric surface.

3. The optical system of claim 2, wherein the surface is a free-form surface.

4. The optical system of claim 2, wherein the surface is a flat surface.

5. The integrated micro spectrometer optical system based on the free-form surface prism as claimed in claim 1, characterized in that the collimating region (202) and the focusing region (204) are the same non-rotationally symmetric surface.

6. The optical system of claim 5, wherein the surface is a free-form surface.

7. The optical system of the integrated micro spectrometer based on the free-form surface prism as claimed in claim 1, wherein the planar diffraction grating (203) is not interfered with the entrance pupil plane (201) and the exit surface (205).

8. The optical system of the integrated micro spectrometer based on the free-form surface prism as claimed in claim 1, wherein the substrate of the free-form surface prism is made of fluorine-based glass, optical plastic, zinc selenide or sulfur-based material.

9. The optical system of the integrated micro spectrometer based on the free-form surface prism as claimed in claim 1, wherein the size of the entrance slit (1) is 2mm x 16 μm, and the grating groove density of the planar diffraction grating (203) is 300 line/mm.

10. The optical system of the integrated micro spectrometer based on the free-form surface prism as claimed in claim 1, wherein the optical system has an F number of 5, a spectral range of 0.4-1 μm, and a spectral resolution of a pixel of 3.5 nm.

Technical Field

The invention relates to the field of optical systems and device design, in particular to an integrated micro spectrometer optical system based on a free-form surface prism.

Background

In the beginning of the 70 th century of the twentieth century, a dispersive imaging spectrometer has appeared, which detects a target and can acquire image information and spectral information, and is widely applied to scientific researches such as remote sensing, exploration and the like, such as mineral identification, agriculture and forestry monitoring, military reconnaissance, sea color and atmospheric detection and the like. The optical system of the imaging spectrometer usually consists of a telescope objective and a spectrometer, the main core of the spectrum detection function is the spectrometer, and the portable spectrometer preferably considers small volume and weight rather than ultrahigh resolution. The micro spectrometer system has very important significance in military fields such as aerospace remote sensing and military reconnaissance, and has wide commercial prospect in portable equipment such as handheld spectrometers, mobile phones and notebook computers. However, the traditional spectrometer design adopts a multi-piece combined refraction or reflection structure design, and the system has a large volume and a complicated mechanical structure design, so that the traditional spectrometer is not beneficial to complex and variable environmental application.

The patent of the invention with the publication number of CN104406691A discloses an imaging spectrometer light splitting system based on a single free-form surface, and the system consists of an incident slit, a free-form surface reflector, a plane blazed grating and an image surface. The invention is characterized in that a non-rotational symmetrical free-form surface reflector is used twice to respectively serve as a collimating mirror and an imaging mirror, and a high-performance plane blazed grating with mature processing technology is matched, so that the spectrometer light splitting system with simple and compact structure, small aberration, low distortion and high efficiency is realized. But the optical system still has a multi-part composition and requires the installation and adjustment of the lens and the grating and the design of an external positioning structure. The invention patent with publication number CN110470394A discloses an optical system of an ultra-compact spectrometer, which comprises a field diaphragm, a grating, a compound lens, a first reflector, a second reflector and a filter, wherein the optical system is of a refraction and reflection type, the grating is a plane reflection grating, the compound lens is passed by light rays for four times, but the optical system still needs a plurality of reflection lenses and lenses to be combined, debugged, positioned and installed, and the external structural design of the optical system is relatively complex.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide an integrated micro spectrometer optical system based on a free-form surface prism, which has low cost, high performance and compact configuration.

The purpose of the invention can be realized by the following technical scheme:

the utility model provides a miniature spectrum appearance optical system of integral type based on free-form surface prism, includes incident slit, free-form surface prism and image plane, free-form surface prism including entering pupil plane, collimation area, focus area and exit surface, collimation area and focus area on be equipped with the speculum, free-form surface prism on still the integration be provided with plane diffraction grating, incident ray is by the incident slit outgoing, through entering pupil plane after the incidence through the collimation area reflection to plane diffraction grating, light after the diffraction beam splitting is through focus area reflection and through the exit surface outgoing, the focus is at image plane formation.

Furthermore, the entrance pupil plane and the exit surface are the same non-rotationally symmetrical surface on the free-form surface prism, and the surface is a free-form surface or a plane.

Further, the collimation area and the focusing area are the same non-rotationally symmetrical surface on the free-form surface prism, and the surface is a free-form surface.

Furthermore, the plane diffraction grating is directly designed and processed on the free-form surface prism and does not interfere with the entrance pupil plane and the exit surface.

Furthermore, the substrate material of the free-form surface prism is fluorine glass, optical plastic, zinc selenide or sulfur material, and if the spectrometer is used for a visible near-infrared band, the substrate material of the free-form surface prism can be fluorine glass or optical plastic such as PMMA, E48R and the like; if the spectrometer is used in the short wave infrared band, the substrate material of the free-form surface prism can be zinc selenide or fluorine series glass, and if the spectrometer is used in the medium wave infrared band, the substrate material of the free-form surface prism can be zinc selenide or sulfur series material.

Further, the size of the entrance slit is 2mm × 16 μm, and the grating groove density of the planar diffraction grating is 300 line/mm.

Furthermore, the F number of the optical system is 5, the spectral range is 0.4-1 μm, and the spectral resolution of the pixel is 3.5 nm.

Compared with the prior art, the invention has the following beneficial effects:

(1) the invention integrally designs the plane diffraction grating and the reflecting mirror on the single free-form surface prism, the reflecting mirror is arranged on the collimation area and the focusing area of the free-form surface prism, the processing is easy, the structure is compact, the cost is low, simultaneously, the free-form surface has enough optimization parameters, the off-axis aberration of the correction system is easy to optimize, the correcting system is suitable for different structural parameters, and the correcting system has the advantages of small aberration, low distortion and high efficiency;

(2) The entrance pupil plane and the exit surface adopted by the invention are the same non-rotationally symmetrical surface on the free-form surface prism, the surface can be set as a plane or a free-form surface, the collimation area and the focusing area are positioned on the same non-rotationally symmetrical free-form surface on the free-form surface prism, and the adjacent two surfaces adopt the same surface shape, thereby being beneficial to integrated injection molding and compression molding and having compact design.

Drawings

FIG. 1 is a schematic diagram of an optical path system of a spectrometer in example 1;

FIG. 2 is a schematic diagram of the optical path system of the spectrometer of example 2;

FIG. 3 is a plot of RMS radius as a function of field of view for different wavelengths in example 1;

FIG. 4 is a plot of RMS radius as a function of wavelength for different fields of view in example 1;

FIG. 5 is a plot of RMS radius versus field of view for different wavelengths in example 2;

FIG. 6 is a plot of RMS radius as a function of wavelength for different fields of view in example 2.

The reference numbers in the figures illustrate:

1. the optical system comprises an incident slit, 2 a free-form surface prism, 3 an image surface, 201 an entrance pupil plane, 202 a collimation area, 203 a plane diffraction grating, 204 a focusing area, 205 an exit surface.

Detailed Description

The invention is described in detail below with reference to the figures and specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.