Reconstruction type spectrograph light collimation light path

Abstract

The invention provides a reconstruction type spectrograph light collimation light path, an optical imaging module comprises four lenses, the four lenses are a positive lens, a negative lens, a negative lens and a positive lens in sequence in the light incidence direction, the focal length of the optical imaging module is 8.04 mm, the image space F number is 0.8, the object height is 144 microns, and the total length is 18.00 mm; the optical imaging module works in a near-infrared band, and the working wavelength range is 1000-2500nm. The collimation light path designed by the invention can be connected with the optical fiber and the spectrum coding plate, and is used for collimating light transmitted by the optical fiber into parallel light and enabling the parallel light to enter the spectrum coding plate. The optical imaging module comprises two aspheric lenses, the imaging quality is greatly improved, all aberrations are comprehensively corrected and balanced during design, light beams from optical fibers can be well collimated, and good parallel light is obtained.

Description

Technical Field

[0001] This invention relates to the field of optical design technology, and in particular to a collimating optical path for a reconstructed spectrometer. Background Technology

[0002] Since the beginning of the 21st century, spectroscopic analysis technology has become a core technology for qualitative and quantitative analysis of substances due to its advantages of speed, non-destructive nature, and accuracy. Demand has surged in fields such as environment, medicine, industry, and food, with high-performance spectrometers being essential for scenarios such as air pollutant monitoring and biological pathology diagnosis. Among these, reconstructive spectrometers, through innovative algorithms, have overcome the limitations of traditional spectrometers in balancing resolution and detection speed, becoming a research hotspot.

[0003] The collimation optical path is a key component of a reconstruction spectrometer, and its performance directly affects the quality of spectral signal acquisition and reconstruction accuracy. Compared to traditional spectrometers, reconstruction spectrometers have more stringent requirements for optical collimation: on the one hand, the reconstruction algorithm is sensitive to the stability of the light field, and angular deviations or uneven light intensity in the collimation optical path can lead to signal distortion; on the other hand, it needs to be compatible with a wide range of light wavelengths, and the differences in the propagation characteristics of different wavelengths can easily reduce the collimation effect due to dispersion and aberrations.

[0004] Current conventional spectrometers mostly employ single lenses or simple lens groups for their collimation paths, resulting in low collimation accuracy and narrow applicable wavelength ranges. While some high-performance systems improve performance, they lead to increased size and cost, and exhibit poor stability in complex environments. Meanwhile, reconstruction spectrometers are evolving towards portability and miniaturization, making it difficult for existing collimation paths to balance high accuracy with miniaturization. Therefore, developing optical collimation paths with high collimation accuracy, wide wavelength range adaptability, miniaturization, and strong stability is crucial for the technological implementation and application expansion of these instruments. Summary of the Invention

[0005] This invention provides a collimating optical path for a reconstructive spectrometer. The optical imaging module operates in the wavelength range of 1000nm to 2500nm. The collimating optical path designed in this invention can connect to an optical fiber and a spectral encoding board. Its function is to collimate the light transmitted from the optical fiber into parallel light before it is incident on the spectral encoding board. The optical imaging module contains two aspherical lenses, significantly improving image quality. Furthermore, its design comprehensively corrects and balances all aberrations, enabling excellent collimation of the beam from the optical fiber and obtaining well-parallel light.

[0006] This invention provides a collimating optical path for a reconstructive spectrometer. The optical imaging module includes a first positive lens, a first negative lens, a second negative lens, and a second positive lens arranged coaxially along the incident direction of the light. The first positive lens is made of HZK4_CDGM, with a aperture diameter of 5.5mm < aperture diameter < 6.5mm, a thickness of 4.0mm < thickness < 5.0mm, a radius of curvature of -37.0mm < radius of curvature of the first surface < -36.0mm, and a radius of curvature of -7.0mm < radius of curvature of the second surface < -6.0mm. The first negative lens is made of HQK3_CDGM, with an aperture diameter of 7.0mm < aperture diameter < 8.0mm, a thickness of 4.0mm < thickness < 5.0mm, and a radius of curvature of -7.5mm < radius of curvature of the first surface. <-6.5mm, -13.0mm < radius of curvature of the second surface <-12.0mm; the material of the second negative lens is HZF6_CDGM, 8.5mm < aperture < 9.5mm, 2.0mm < thickness < 3.0mm, -25.0mm < radius of curvature of the first surface <-24.0mm, 14.0mm < radius of curvature of the second surface <15.0mm; the material of the second positive lens is HZK10_CDGM, 10.0mm < aperture < 11.0mm, 2.0mm < thickness < 3.0mm, 14.0mm < radius of curvature of the first surface <15.0mm, -15.5mm < radius of curvature of the second surface <-14.5mm.

[0007] Optionally, the first positive lens has a light-transmitting aperture of 5.9 mm, a thickness of 4.4 mm, a radius of curvature of -36.5 mm on the first surface, and a radius of curvature of -6.3 mm on the second surface; the first negative lens has a light-transmitting aperture of 7.4 mm, a thickness of 4.5 mm, a radius of curvature of -6.9 mm on the first surface, and a radius of curvature of -12.6 mm on the second surface; the second negative lens has a light-transmitting aperture of 8.8 mm, a thickness of 2.3 mm, a radius of curvature of -24.7 mm on the first surface, and a radius of curvature of 14.3 mm on the second surface; and the second positive lens has a light-transmitting aperture of 9.5 mm, a thickness of 2.2 mm, a radius of curvature of 14.3 mm on the first surface, and a radius of curvature of -14.9 mm on the second surface.

[0008] Optionally, the second negative lens and the second positive lens form a cemented lens.

[0009] Optionally, the distance between the center of the light-emitting surface of the second positive lens and the image plane is 10.0 mm.

[0010] Optionally, the optical dimensions of the optical imaging module are φ9.5×18.00mm.

[0011] Optionally, the optical imaging module has a system focal length of 8.04 mm and an F-number of 0.8.

[0012] Optionally, the optical imaging module operates in the wavelength range of 1000nm to 2500nm.

[0013] Optionally, the object height of the optical imaging module is 144 μm.

[0014] As can be seen from the above technical solutions, the embodiments of the present invention have the following advantages: 1. The collimating optical path of the reconstructed spectrometer has an optical imaging module operating in the wavelength range of 1000nm~2500nm. The optical imaging module includes four lenses, two of which are aspherical lenses, significantly improving imaging quality.

[0015] 2. The collimating optical path of the reconstructed spectrometer has an optical imaging module with a focal length of 8.04 mm, an F-number of 0.8, and a total optical length of 18.00 mm. During the design process, all aberrations were corrected and balanced. The collimating optical path can effectively collimate the beam from the optical fiber, obtaining well-parallel light. The collimating optical path of the reconstructed spectrometer described in section 3 has an object height of 144 μm, while the aperture of a typical optical fiber is only about 30 μm. Therefore, the object height of the collimating optical path of this reconstructed spectrometer is perfectly adequate for matching with the optical fiber. Attached Figure Description

[0016] Figure 1 This is a diagram showing the optical path structure of the optical imaging module of the collimating optical path of the reconstructed spectrometer of the present invention; Figure 2 This is a dot diagram of the optical imaging module of the collimating optical path of the reconstructed spectrometer of the present invention; Figure 3 This is the optical modulation transfer function of the optical imaging module in the collimating optical path of the reconstructed spectrometer of the present invention; Figure reference numerals: 1-First positive lens; 2-First negative lens; 3-Second negative lens; 4-Second positive lens; STO-Aperture stop; IMA-Image plane. Detailed Implementation

[0017] To enable those skilled in the art to better understand the present invention, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0018] Please refer to Figure 1The diagram below illustrates the optical path structure of this reconstructed spectrometer. The optical imaging module of the collimating optical path includes four lenses arranged in a positive-negative-negative-positive configuration, including two aspherical lenses, significantly improving image quality. The four lenses are a first positive lens 1, a first negative lens 2, a second negative lens 3, and a second positive lens 4, arranged coaxially along the incident light direction. The first positive lens 1 is made of HZK4_CDGM material, with a aperture diameter of 5.5mm < aperture diameter < 6.5mm, a thickness of 4.0mm < thickness < 5.0mm, a curvature radius of the first surface of -37.0mm < radius of curvature of the second surface of -36.0mm, and a curvature radius of curvature of -7.0mm < radius of curvature of the second surface of -6.0mm. The first negative lens 2 is made of HQK3_CDGM material, with a aperture diameter of 7.0mm < aperture diameter < 8.0mm, a thickness of 4.0mm < thickness < 5.0mm, a curvature radius of curvature of -7.5mm < radius of curvature of the first surface of -6.5mm, and a curvature radius of -13mm. The second negative lens 3 is made of HZF6_CDGM, with a light-transmitting aperture of 8.5mm and a thickness of 3.0mm. The second negative lens 3 is made of HZF6_CDGM, with a light-transmitting aperture of 8.5mm and a thickness of 3.0mm. The second positive lens 4 is made of HZK10_CDGM, with a light-transmitting aperture of 10.0mm and a thickness of 3.0mm. The second positive lens 4 is made of HZK10_CDGM, with a light-transmitting aperture of 10.0mm and a thickness of 3.0mm. The second negative lens 3 is made of HZF6_CDGM, with a light-transmitting aperture of 8.5mm and a thickness of 9.5mm. The second negative lens 3 is made of HZF6_CDGM, with a light-transmitting aperture of 8.5mm and a thickness of 9.5mm. The second negative lens 3 is made of HZF6_CDGM, with a light-transmitting aperture of 8.5mm and a thickness of 3.0mm. The second negative lens 4 is made of HZK10_CDGM, with a light-transmitting aperture of 10.0mm and a thickness of 11.0mm. The second positive lens 4 is made of HZK10_CDGM, with a light-transmitting aperture of 10.0mm and a thickness of 11.0mm. The second positive lens 4 is made of HZK10_CDGM, with a light-transmitting aperture of 10.0mm and a thickness of 3 ...

[0019] In one embodiment, the first positive lens 1 has a light-transmitting aperture of 5.9 mm, a thickness of 4.4 mm, a first surface radius of curvature of -36.5 mm, and a second surface radius of curvature of -6.3 mm; the first negative lens 2 has a light-transmitting aperture of 7.4 mm, a thickness of 4.5 mm, a first surface radius of curvature of -6.9 mm, and a second surface radius of curvature of -12.6 mm; the second negative lens 3 has a light-transmitting aperture of 8.8 mm, a thickness of 2.3 mm, a first surface radius of curvature of -24.7 mm, and a second surface radius of curvature of 14.3 mm; and the second positive lens 4 has a light-transmitting aperture of 9.5 mm, a thickness of 2.2 mm, a first surface radius of curvature of 14.3 mm, and a second surface radius of curvature of -14.9 mm. This allows the optical imaging module of the collimation path of the reconstructed spectrometer to have a system focal length of 8.04 mm, an F number of 0.8, an object height of 144 μm, and external dimensions of φ9.5 × 18.00 mm, enabling it to effectively collimate the beam from the optical fiber and obtain good parallel light.

[0020] In one embodiment, the second negative lens 3 and the second positive lens 4 form a cemented lens, and the system achieves good correction of chromatic aberration through the combination of the optical materials of the two lenses.

[0021] In one embodiment, the optical imaging module of the collimation optical path of the reconstructed spectrometer has a working wavelength range of 1000nm~2500nm, a focal length of 8.04mm, an F number of 0.8, an object height of 144μm, and a total optical length of 18.00mm. During the design process, all aberrations were corrected and balanced, which can effectively collimate the beam from the optical fiber and obtain good parallel light.

[0022] In this embodiment of the invention, the optical imaging module of the collimating optical path of the reconstructed spectrometer includes four lenses, two of which are aspherical lenses, which significantly improves the imaging quality.

[0023] The lens of this invention emits parallel light. To facilitate observation, an ideal virtual lens is placed behind the lens. The quality of the parallel light is then judged by observing the quality of the image spot formed by the virtual lens. Figure 2 As shown, Figure 2 This is a dot plot of the optical imaging module of the collimating optical path of the reconstructed spectrometer of the present invention. It can be seen from the figure that the RMS of the imaging blur spot corresponding to each field of view is less than 0.4 μm, indicating that the quality of the parallel light emitted by the lens is good.

[0024] Please refer to Figure 3 The figure shows the optical modulation transfer function (MTF) of the optical imaging module of the collimating optical path of the reconstructed spectrometer of the present invention. As can be seen from the figure, the MTF of each field of view is higher than 0.7 in the spatial frequency range of less than 100 cycles / mm, indicating that the quality of the parallel light emitted from the lens of the collimating optical path of the reconstructed spectrometer is good.

[0025] The following shows the lens data of the optical imaging module of the collimating optical path of the reconstructed spectrometer. Table 1 shows the relevant optical parameters of each glass lens in the optical imaging module of the collimating optical path of the reconstructed spectrometer.

[0026] Table 1 Face number Surface type radius of curvature R Thickness D Refractive index nd / Dispersion coefficient vd K OBJ spherical endless 11.8339 S1 aspherical -36.5288 4.4445 1.60881 / 58.9 13.8903 S2 aspherical -6.2563 0.1000 -0.0810 S3 spherical -6.8704 4.5468 1.48746 / 70.1 S4 spherical -12.6078 0.1000 S5 spherical -24.6833 2.3050 1.75521 / 27.5 S6 spherical 14.2897 2.2465 1.62209 / 56.7 STO spherical -14.8283 4.2573 S8 spherical endless 10.0000 IMA spherical endless 0.0000 The aspherical surface formula used in this embodiment of the invention is as follows: Where z is the sag of the aspherical surface at a position of radius r along the optical axis, from the vertex of the aspherical surface; c is the paraxial curvature of the aspherical surface; and k is the conic coefficient. i is the correction coefficient of the i-th order for the aspherical surface.

[0027] Table 2 shows the coefficients of higher-order terms for each aspherical surface in this embodiment.

[0028] Table 2 4th order coefficients 6th order coefficients 8th order coefficients 10th order coefficients 12th order coefficients 14th order coefficients 16th order coefficients S1 -0.0006 -3.6042e-005 1.9534e-006 -2.6474e-007 -1.3788e-008 3.2349e-009 -1.8329e-010 S2 -0.0002 -3.1572e-006 -9.4755e-007 3.9293e-008 -2.6563e-010 -5.9330e-009 6.7205e-012 The optical imaging module of the collimating optical path of the reconstructed spectrometer described in this invention has a focal length of 8.04 mm, an F-number of 0.8, an object height of 144 μm, a total system optical length of 18.00 mm, and a wavelength range of 1000 nm to 2500 nm. It includes four lenses, two of which are aspherical, significantly improving imaging quality. All aberrations were corrected and balanced during the design process, enabling good collimation of the beam from the optical fiber and obtaining well-parallel light.

[0029] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A collimating optical path for a reconstructed spectrometer, characterized in that its optical imaging module comprises a first positive lens, a first negative lens, a second negative lens, and a second positive lens arranged coaxially along the incident direction of the light rays; The material of the first positive lens is HZK4_CDGM, with 5.5mm < aperture diameter < 6.5mm, 4.0mm < thickness < 5.0mm, -37.0mm < radius of curvature of the first surface < -36.0mm, and -7.0mm < radius of curvature of the second surface < -6.0mm; The material of the first negative lens is HQK3_CDGM, with 7.0mm < aperture diameter < 8.0mm, 4.0mm < thickness < 5.0mm, -7.5mm < radius of curvature of the first surface < -6.5mm, and -13.0mm < radius of curvature of the second surface < -12.0mm; The material of the second negative lens is HZF6_CDGM, with a light transmission diameter of 8.5mm < aperture diameter < 9.5mm, a thickness of 2.0mm < 3.0mm, a radius of curvature of -25.0mm < radius of curvature of the first surface < -24.0mm, and a radius of curvature of 14.0mm < radius of curvature of the second surface < 15.0mm; The material of the second positive lens is HZK10_CDGM, with 10.0mm < aperture diameter < 11.0mm, 2.0mm < thickness < 3.0mm, 14.0mm < radius of curvature of the first surface < 15.0mm, and -15.5mm < radius of curvature of the second surface < -14.5mm; The optical imaging module of the reconstructed spectrometer as described in claim 1 is characterized in that: The first positive lens has a light-transmitting aperture of 5.9 mm, a thickness of 4.4 mm, a radius of curvature of -36.5 mm on the first surface, and a radius of curvature of -6.3 mm on the second surface. The first negative lens has a light-transmitting aperture of 7.4 mm, a thickness of 4.5 mm, a radius of curvature of -6.9 mm on the first surface, and a radius of curvature of -12.6 mm on the second surface. The second negative lens has a light-transmitting aperture of 8.8 mm, a thickness of 2.3 mm, a radius of curvature of -24.7 mm on the first surface, and a radius of curvature of 14.3 mm on the second surface. The second positive lens has a light-transmitting aperture of 9.5 mm, a thickness of 2.2 mm, a radius of curvature of 14.3 mm on the first surface, and a radius of curvature of -14.9 mm on the second surface. The optical imaging module of the reconstructed spectrometer as described in claim 1 is characterized in that the second negative lens and the second positive lens form a cemented lens.

2. The optical collimation path of the reconstructed spectrometer as described in claim 1, wherein the optical imaging module is characterized in that: the distance between the center of the light emitting surface of the second positive lens and the image plane is 10.0 mm.

3. The optical collimation path of the reconstructed spectrometer as described in claim 1, wherein the optical imaging module is characterized in that: the optical dimensions of the optical imaging module are φ9.5×18.00mm.

4. The optical collimation path of the reconstructed spectrometer as described in claim 1, wherein the optical imaging module is characterized in that: the system focal length of the optical imaging module is 8.04 mm and the F number is 0.

8.

5. The optical collimation path of the reconstructed spectrometer as described in claim 1, wherein the optical imaging module is characterized in that: the working wavelength range of the optical imaging module is 1000nm~2500nm.

6. The optical collimation path of the reconstructed spectrometer as described in claim 1, wherein the optical imaging module is characterized in that: the object height of the optical imaging module is 144 μm.

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