Small Color Distortion Slit Spectrometer

Abstract

This application discloses a small-color-distortion slit spectrometer. The color distortion range of the small-color-distortion slit spectrometer is less than or equal to 1 micrometer. The small-color-distortion slit spectrometer includes, arranged sequentially from the object side to the image side: a slit, located on the light-emitting side of the light source, which acts as a field stop and provides resolution filtering for the divergent beam emitted by the light source; the length of the slit is in the range of 1mm-15mm; a spectrometer collimating lens group, used to collimate the divergent beam after slit filtering, so as to convert the divergent beam into a parallel beam; a grating, used to split the parallel beam to form spectra of different angles and colors; and a spectrometer focusing lens group, used to focus the spectra of different angles and colors onto the image plane; the focal length of the spectrometer focusing lens group is f. f The focal length of the collimating lens group of the spectrometer is f. c f c and f f Satisfying the relation: 1≤f f ÷f c ≤5. The small chromatic aberration slit spectrometer of this application can achieve high-resolution, clear imaging with a slit length of 1mm-15mm and chromatic aberration of less than or equal to 1 micrometer.

Description

Technical Field

[0001] This invention relates to the field of optical technology, and more specifically to a small-color-distortion slit spectrometer. Background Technology

[0002] A spectrometer is a fusion of optical imaging and spectral analysis technologies. It can acquire the corresponding spectral information of a target while simultaneously obtaining the target's image information, making it a comprehensive optical instrument for acquiring target information. Imaging spectrometers organically combine imaging and spectral technologies. By introducing a "slit," they effectively reconcile the contradictions between imaging and spectral analysis, allowing for the simultaneous acquisition of both image and spectral information of the target. This results in an imaging spectral data cube of the target, from which the corresponding spatial image and the spectral curve at any location within the spatial image can be extracted. This achieves the fusion of imaging and spectral technologies.

[0003] Chromatic distortion is a crucial performance indicator for slit spectrometers. It refers to the varying degrees of deviation between light of different wavelengths when it passes through the slit and is imaged onto the camera's image plane, resulting in spectral image distortion. Lower chromatic distortion indicates higher resolution and accuracy for the spectrometer. For applications requiring precise wavelength measurements, such as chemical analysis and biomedicine, controlling chromatic distortion is particularly important. The slit length should be selected based on the specific application and the required spectral resolution. A longer slit provides a wider field of view. For high-resolution spectra, a shorter slit is preferable to improve resolution and image sharpness. However, an excessively short slit can reduce the field of view, potentially missing important spectral information.

[0004] Therefore, in applications requiring coverage of a wide spectral range and precise wavelength measurement, the slit length can be appropriately increased to expand the spectrometer's field of view. However, it's important to note that increasing the slit length also reduces the spectrometer's resolution and imaging sharpness, thus affecting the accuracy of wavelength measurement. Therefore, researching and developing slit spectrometers with low chromatic distortion and a large field of view is a pressing issue that needs to be addressed. Summary of the Invention

[0005] The purpose of this invention is to propose a spectrometer that can achieve high-resolution, clear imaging with a slit length of 1mm-15mm and color distortion of less than or equal to 1 micrometer.

[0006] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0007] A small-color-distortion slit spectrometer, wherein the color distortion range of the small-color-distortion slit spectrometer is less than or equal to 1 micrometer, and the small-color-distortion slit spectrometer comprises the following components arranged sequentially from the object side to the image side:

[0008] A slit is set on the light-emitting side of the light source. The slit serves as a field stop and plays a resolution filtering role on the diverging light beam emitted by the light source. The length of the slit ranges from 1mm to 15mm.

[0009] The spectrometer collimating lens group is used to collimate the divergent beam after the slit filtering, so as to convert the divergent beam into a parallel beam;

[0010] A grating, used to split the parallel beam of light to form spectra of different angles and colors; and

[0011] The spectrometer focusing lens assembly is used to focus the spectra of different angles and colors onto the image plane, and the focal length of the spectrometer focusing lens assembly is f. f The focal length of the collimating lens group of the spectrometer is f. c f c and f f Satisfying the relation: 1≤f f ÷f c ≤5.

[0012] Furthermore, the width of the slit ranges from 1 micrometer to 100 micrometers.

[0013] Furthermore, a filter is provided between the collimating lens group of the spectrometer and the grating, the filter being used to filter out spectral bands outside the working wavelength range in the parallel beam.

[0014] Furthermore, the operating wavelength range is 400nm-700nm.

[0015] Furthermore, the range of the grating line pairs is 600 lp / mm to 1800 lp / mm.

[0016] Furthermore, the collimating lens group of the spectrometer is composed of a first number of lenses arranged on the same optical axis, and the focusing lens group of the spectrometer is composed of a second number of lenses arranged on the same optical axis. The first number of lenses constituting the collimating lens group of the spectrometer and the second number of lenses constituting the focusing lens group of the spectrometer are connected in their optical paths.

[0017] Furthermore, the first quantity is 7, and the collimating lens group of the spectrometer includes a first spherical lens, a second spherical lens, a third spherical lens, a fourth spherical lens, a fifth spherical lens, a sixth spherical lens, and a seventh spherical lens arranged sequentially from the object side to the image side;

[0018] The second quantity is 6, and the focusing lens group of the spectrometer includes an eighth spherical lens, a ninth spherical lens, a tenth spherical lens, an eleventh spherical lens, a twelfth spherical lens, and a thirteenth spherical lens arranged sequentially from the object side to the image side.

[0019] Furthermore, the first spherical lens has positive optical power and a rear surface radius of curvature of less than 0. The first spherical lens is used to eliminate spherical aberration, axial chromatic aberration, astigmatism, distortion, and magnification chromatic aberration.

[0020] The second spherical lens has negative optical power, a front surface radius of curvature less than 0, and a rear surface radius of curvature greater than 0. The second spherical lens is used to eliminate distortion, spherical aberration, and coma.

[0021] The third spherical lens has positive optical power, a front surface radius of curvature greater than 0, and a rear surface radius of curvature less than 0. The third spherical lens is used to eliminate spherical aberration, coma, astigmatism, and distortion.

[0022] The fourth spherical lens has negative optical power and a front surface radius of curvature of less than 0. The fourth spherical lens is used to eliminate coma, astigmatism and distortion.

[0023] The fifth spherical lens has negative optical power and a rear surface radius of curvature greater than 0. The fifth spherical lens is used to eliminate spherical aberration, coma, and axial chromatic aberration.

[0024] The sixth spherical lens is a cemented lens composed of a negative lens, a positive lens, and a negative lens bonded together in sequence. The sixth spherical lens is used to eliminate spherical aberration, coma, axial chromatic aberration, and magnification chromatic aberration.

[0025] The seventh spherical lens is a positive focal length meniscus that bends toward the slit and is used to eliminate spherical aberration, coma, axial chromatic aberration, and magnification chromatic aberration.

[0026] Furthermore, the eighth spherical lens has positive optical power and a front surface radius of curvature greater than 0. The eighth spherical lens is used to eliminate spherical aberration, coma, axial chromatic aberration, astigmatism, and magnification chromatic aberration.

[0027] The ninth spherical lens has negative optical power, a front surface radius of curvature less than 0, and a rear surface radius of curvature greater than 0. The ninth spherical lens is used to eliminate spherical aberration, axial chromatic aberration, coma, and astigmatism.

[0028] The tenth spherical lens has positive optical power and a rear surface curvature radius of less than 0. The tenth spherical lens is used to eliminate spherical aberration, magnification chromatic aberration, and axial chromatic aberration.

[0029] The eleventh spherical lens is a cemented doublet lens composed of a positive lens and a negative lens bonded together in sequence, used to eliminate spherical aberration, coma, and chromatic aberration.

[0030] The twelfth spherical lens has positive optical power, a front surface radius of curvature greater than 0, and a rear surface radius of curvature less than 0. The twelfth spherical lens is used to eliminate spherical aberration, coma, astigmatism, distortion, axial chromatic aberration, and magnification chromatic aberration.

[0031] The thirteenth spherical lens has negative optical power, a front surface radius of curvature of less than 0, and a rear surface radius of curvature of greater than 0. The thirteenth spherical lens is used to eliminate spherical aberration, coma, astigmatism, distortion, axial chromatic aberration, and magnification chromatic aberration.

[0032] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: the focal length f of the focusing lens group of the spectrometer of the small color distortion slit spectrometer of this application... f The focal length f of the collimating lens group of the spectrometer c Satisfying the relation: 1≤f f ÷f c The slit length is set to 1mm-15mm to make the color distortion range of the spectrometer less than or equal to 1 micrometer. Compared with the prior art, this method expands the field of view of the spectrometer while improving the resolution and imaging clarity of the spectrometer, making it suitable for applications with a wide spectral range and requiring precise wavelength measurement. Attached Figure Description

[0033] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0034] Figure 1 This shows a schematic diagram of the structure of the small-color distortion slit spectrometer according to an embodiment of the present invention;

[0035] Figure 2 This is a schematic diagram of the MTF curve at a working wavelength of 400nm in specific embodiment 1 of the present invention;

[0036] Figure 3 This is a schematic diagram of the MTF curve at a working wavelength of 550nm in specific embodiment 1 of the present invention;

[0037] Figure 4 This is a schematic diagram of the MTF curve at a working wavelength of 700nm in specific embodiment 1 of the present invention;

[0038] Figure 5 This is a schematic diagram of the MTF curve at a working wavelength of 400nm in specific embodiment 2 of the present invention;

[0039] Figure 6 This is a schematic diagram of the MTF curve at a working wavelength of 550nm in specific embodiment 2 of the present invention;

[0040] Figure 7 This is a schematic diagram of the MTF curve at a working wavelength of 700nm in specific embodiment 2 of the present invention;

[0041] Figure 8 This is a schematic diagram of the MTF curve at a working wavelength of 400nm in specific embodiment 3 of the present invention;

[0042] Figure 9 This is a schematic diagram of the MTF curve at a working wavelength of 550nm in specific embodiment 3 of the present invention;

[0043] Figure 10 This is a schematic diagram of the MTF curve at a working wavelength of 700nm in specific embodiment 3 of the present invention.

[0044] Explanation of reference numerals in the attached figures:

[0045] 1-Slit; 2-Raster; 3-Filter; 4-Image plane; L1-First spherical lens; L2-Second spherical lens; L3-Third spherical lens; L4-Fourth spherical lens; L5-Fifth spherical lens; L6-Sixth spherical lens; L7-Seventh spherical lens; L8-Eighth spherical lens; L9-Ninth spherical lens; L10-Tenth spherical lens; L11-Eleventh spherical lens; L12-Twelfth spherical lens; L13-Thirteenth spherical lens. Detailed Implementation

[0046] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0047] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0048] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing the invention and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0049] Furthermore, in addition to indicating direction or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in certain situations to indicate a dependency or connection. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0050] Furthermore, the terms "installation," "setup," "equipped with," "connection," "linking," and "socketing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0051] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0052] Please see Figure 1 This embodiment provides a small-color-distortion slit-1 spectrometer, which includes a slit 1, a spectrometer collimating lens group, a grating 2, and a spectrometer focusing lens group arranged sequentially from the object side to the image side. The color distortion range of this small-color-distortion slit-1 spectrometer is less than or equal to 1 micrometer.

[0053] Specifically, slit 1 is positioned on the light-emitting side of the light source. Slit 1 acts as a field stop and filters the diverging beam emitted by the light source to improve resolution. The length of slit 1 ranges from 1 mm to 15 mm, and the width ranges from 1 micrometer to 100 micrometers. It should be noted that the smaller the width of slit 1, the higher the resolution of the spectrometer and the weaker the light transmission energy; the longer the length of slit 1, the larger the field of view of the spectrometer. This application does not impose specific limitations on the length and width of slit 1, and these values ​​can be adjusted according to design requirements, which will not be elaborated here.

[0054] The collimating lens group of the spectrometer is used to collimate the divergent beam after filtering through slit 1, thereby converting the divergent beam into a parallel beam. The collimating lens group consists of a first number of lenses arranged along the optical axis. The focusing lens group of the spectrometer is used to focus spectra of different angles and colors onto image plane 4. The focusing lens group consists of a second number of lenses arranged along the optical axis. The optical paths of the first number of lenses constituting the collimating lens group and the second number of lenses constituting the focusing lens group are connected. The focal length of the focusing lens group is f. f The focal length of the collimating lens group of the spectrometer is f. c f c and f f Satisfying the relation: 1≤f f ÷f c ≤5.

[0055] In this embodiment, the first quantity is specifically 7, and the second quantity is specifically 6. The spectrometer collimating lens group includes a first spherical lens L1, a second spherical lens L2, a third spherical lens L3, a fourth spherical lens L4, a fifth spherical lens L5, a sixth spherical lens L6, and a seventh spherical lens L7, arranged sequentially from the object side to the image side. The spectrometer focusing lens group includes an eighth spherical lens L8, a ninth spherical lens L9, a tenth spherical lens L10, an eleventh spherical lens L11, a twelfth spherical lens L12, and a thirteenth spherical lens L13, arranged sequentially from the object side to the image side.

[0056] In detail, the first spherical lens L1 has positive optical power and a rear surface radius of curvature less than 0. It is used to eliminate spherical aberration, axial chromatic aberration, astigmatism, distortion, and magnification chromatic aberration. The second spherical lens L2 has negative optical power, a front surface radius of curvature less than 0, and a rear surface radius of curvature greater than 0. It is used to eliminate distortion, spherical aberration, and coma. The third spherical lens L3 has positive optical power, a front surface radius of curvature greater than 0, and a rear surface radius of curvature less than 0. It is used to eliminate spherical aberration, coma, astigmatism, and distortion. The fourth spherical lens L4 has negative optical power and a front surface radius of curvature less than 0. It is used to eliminate coma, astigmatism, and distortion. The fifth spherical lens L5 has negative optical power and a rear surface radius of curvature greater than 0. It is used to eliminate spherical aberration, coma, and axial chromatic aberration. The sixth spherical lens L6 is a cemented triplet lens composed of a negative lens, a positive lens, and a negative lens bonded together in sequence. The sixth spherical lens L6 is used to eliminate spherical aberration, coma, axial chromatic aberration, and magnification chromatic aberration. The seventh spherical lens L7 is a positive-power meniscus lens bent towards slit 1, used to eliminate spherical aberration, coma, axial chromatic aberration, and magnification chromatic aberration.

[0057] The eighth spherical lens, L8, has positive optical power and a front surface radius of curvature greater than 0. It is used to eliminate spherical aberration, coma, axial chromatic aberration, astigmatism, and lateral chromatic aberration. The ninth spherical lens, L9, has negative optical power, with a front surface radius of curvature less than 0 and a rear surface radius of curvature greater than 0. It is used to eliminate spherical aberration, axial chromatic aberration, coma, and astigmatism. The tenth spherical lens, L10, has positive optical power and a rear surface radius of curvature less than 0. It is used to eliminate spherical aberration, lateral chromatic aberration, and axial chromatic aberration. The eleventh spherical lens, L11, is a cemented doublet lens composed of a positive and a negative lens bonded together sequentially. It is used to eliminate spherical aberration, coma, and lateral chromatic aberration. The twelfth spherical lens, L12, has positive optical power, with a front surface radius of curvature greater than 0 and a rear surface radius of curvature less than 0. It is used to eliminate spherical aberration, coma, astigmatism, distortion, axial chromatic aberration, and lateral chromatic aberration. The thirteenth spherical lens L13 has negative optical power, with a front surface radius of curvature less than 0 and a rear surface radius of curvature greater than 0. The thirteenth spherical lens L13 is used to eliminate spherical aberration, coma, astigmatism, distortion, axial chromatic aberration, and magnification chromatic aberration.

[0058] The grating 2 is used to split the parallel beam converted by the collimating lens group of the spectrometer to form spectra of different angles and colors. In this embodiment, the grating 2 is specifically a transmission grating. Transmission gratings are existing technology, and their principles and structures are well known to those skilled in the art, and will not be described in detail here.

[0059] To filter out spectral bands outside the working wavelength range in the parallel beam and obtain a specific spectral range, thereby improving accuracy, in this embodiment, a filter 3 is also provided between the collimating lens group of the spectrometer and the grating 2. In this embodiment, the working wavelength range is specifically 400nm-700nm. The line pair range of the grating 2 is 600lp / mm-1800lp / mm.

[0060] The following are some specific embodiments of the small-color distortion slit spectrometer provided in this invention: Specific Implementation Example 1

[0062] The slit 1 is 12mm long, and the focal length f of the collimating lens group of the spectrometer is... c = 75.217mm, focal length f of the focusing lens group of the spectrometer f =116.2448, f f ÷f c =1.545. The specific parameters of slit 1, spectrometer collimating lens group, spectrometer focusing lens group, grating 2, filter 3, and image plane are shown in Table 1 below:

[0063]

[0064] Table 1

[0065] See Figures 2 to 4 The figures are schematic diagrams of the MTF curves of the small color distortion slit spectrometer provided in Specific Embodiment 1 of the present invention at working wavelengths of 400nm, 550nm and 700nm, respectively. They all have good characteristics close to the diffraction limit, and the maximum color distortion of the small color distortion slit spectrometer is 1 micrometer. Specific Implementation Example 2

[0067] The slit 1 is 8mm long, and the focal length f of the collimating lens group of the spectrometer is... c =50mm, focal length f of the focusing lens group of the spectrometer f =115.541mm, f f ÷f c =2.31. The specific parameters of slit 1, spectrometer collimating lens group, spectrometer focusing lens group, grating 2, filter 3, and image plane are shown in Table 2 below:

[0068]

[0069] Table 2

[0070] See Figures 5 to 7 The figures are schematic diagrams of the MTF curves of the small color distortion slit spectrometer provided in Specific Embodiment 2 of the present invention at working wavelengths of 400nm, 550nm and 700nm, respectively. They all have good characteristics close to the diffraction limit, and the maximum color distortion of the small color distortion slit spectrometer is 1 micrometer. Specific Implementation Example 3

[0072] The length of slit 1 is 4.6 mm, and the focal length f of the collimating lens group of the spectrometer is... c =28.7074mm, focal length f of the focusing lens group of the spectrometer f =114.8735mm, f f ÷f c =4. The specific parameters of slit 1, spectrometer collimating lens group, spectrometer focusing lens group, grating 2, filter 3, and image plane are shown in Table 3 below:

[0073]

[0074] Table 3

[0075] See Figures 8 to 10 The figures are schematic diagrams of the MTF curves of the small color distortion slit spectrometer provided in Specific Embodiment 3 of the present invention at working wavelengths of 400nm, 550nm and 700nm, respectively. They all have good characteristics close to the diffraction limit, and the maximum color distortion of the small color distortion slit spectrometer is 1 micrometer.

[0076] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A small-color-distortion slit spectrometer, characterized in that, The color distortion range of the small color distortion slit spectrometer is less than or equal to 1 micrometer, and the small color distortion slit spectrometer comprises the following components arranged sequentially from the object side to the image side: A slit is set on the light-emitting side of the light source. The slit serves as a field stop and plays a resolution filtering role on the diverging light beam emitted by the light source. The length of the slit ranges from 1mm to 15mm. The spectrometer collimating lens group is used to collimate the divergent beam after the slit filtering, so as to convert the divergent beam into a parallel beam; A grating, used to split the parallel beam of light to form spectra of different angles and colors; and A spectrometer focusing lens group is used to focus the spectra of different angles and colors onto the image plane. The focal length of the spectrometer focusing lens group is ff, and the focal length of the spectrometer collimating lens group is fc. fc and ff satisfy the relationship: 1≤ff÷fc≤5. The collimating lens group of the spectrometer is composed of a first number of lenses arranged coaxially, and the focusing lens group of the spectrometer is composed of a second number of lenses arranged coaxially. The first number of lenses constituting the collimating lens group of the spectrometer and the second number of lenses constituting the focusing lens group of the spectrometer are connected in optical path. The first quantity is 7, and the collimating lens group of the spectrometer includes a first spherical lens, a second spherical lens, a third spherical lens, a fourth spherical lens, a fifth spherical lens, a sixth spherical lens and a seventh spherical lens arranged sequentially from the object side to the image side; The second quantity is 6, and the focusing lens group of the spectrometer includes an eighth spherical lens, a ninth spherical lens, a tenth spherical lens, an eleventh spherical lens, a twelfth spherical lens, and a thirteenth spherical lens arranged sequentially from the object side to the image side; The first spherical lens has positive optical power and a rear surface radius of curvature of less than 0. The first spherical lens is used to eliminate spherical aberration, axial chromatic aberration, astigmatism, distortion, and magnification chromatic aberration. The second spherical lens has negative optical power, a front surface radius of curvature less than 0, and a rear surface radius of curvature greater than 0. The second spherical lens is used to eliminate distortion, spherical aberration, and coma. The third spherical lens has positive optical power, a front surface radius of curvature greater than 0, and a rear surface radius of curvature less than 0. The third spherical lens is used to eliminate spherical aberration, coma, astigmatism, and distortion. The fourth spherical lens has negative optical power and a front surface radius of curvature of less than 0. The fourth spherical lens is used to eliminate coma, astigmatism and distortion. The fifth spherical lens has negative optical power and a rear surface radius of curvature greater than 0. The fifth spherical lens is used to eliminate spherical aberration, coma, and axial chromatic aberration. The sixth spherical lens is a cemented lens composed of a negative lens, a positive lens, and a negative lens bonded together in sequence. The sixth spherical lens is used to eliminate spherical aberration, coma, axial chromatic aberration, and magnification chromatic aberration. The seventh spherical lens is a positive focal power meniscus that bends toward the slit and is used to eliminate spherical aberration, coma, axial chromatic aberration and magnification chromatic aberration; The eighth spherical lens has positive optical power and a front surface radius of curvature greater than 0. The eighth spherical lens is used to eliminate spherical aberration, coma, axial chromatic aberration, astigmatism, and magnification chromatic aberration. The ninth spherical lens has negative optical power, a front surface radius of curvature less than 0, and a rear surface radius of curvature greater than 0. The ninth spherical lens is used to eliminate spherical aberration, axial chromatic aberration, coma, and astigmatism. The tenth spherical lens has positive optical power and a rear surface curvature radius of less than 0. The tenth spherical lens is used to eliminate spherical aberration, magnification chromatic aberration, and axial chromatic aberration. The eleventh spherical lens is a cemented doublet lens composed of a positive lens and a negative lens bonded together in sequence, used to eliminate spherical aberration, coma, and chromatic aberration. The twelfth spherical lens has positive optical power, a front surface radius of curvature greater than 0, and a rear surface radius of curvature less than 0. The twelfth spherical lens is used to eliminate spherical aberration, coma, astigmatism, distortion, axial chromatic aberration, and magnification chromatic aberration. The thirteenth spherical lens has negative optical power, a front surface radius of curvature of less than 0, and a rear surface radius of curvature of greater than 0. The thirteenth spherical lens is used to eliminate spherical aberration, coma, astigmatism, distortion, axial chromatic aberration, and magnification chromatic aberration.

2. The small-color distortion slit spectrometer as described in claim 1, characterized in that, The width of the slit ranges from 1 micrometer to 100 micrometers.

3. The small-color distortion slit spectrometer as described in claim 2, characterized in that, A filter is also provided between the collimating lens group of the spectrometer and the grating. The filter is used to filter out spectral bands outside the working wavelength range in the parallel beam.

4. The small-color distortion slit spectrometer as described in claim 3, characterized in that, The operating wavelength range is 400nm-700nm.

5. The small-color distortion slit spectrometer as described in claim 4, characterized in that, The range of the grating line pairs is 600 lp / mm to 1800 lp / mm.

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