Large-diameter refraction type dispersion lens

Abstract

The invention discloses a large-aperture refractive dispersion lens, which belongs to the technical field of optics and consists of a plurality of lens groups which sequentially comprise a first lens group, a second lens group and a third lens group. The first lens group is composed of a plano-convex lens and two meniscus lenses, the second lens group is an achromatic lens group and is composed of a doublet lens and a plano-convex lens, and the third lens group is composed of three single lenses. On the premise of meeting the basic requirements of the spectral confocal dispersion lens, the good focusing of light with different wavelengths at different positions in the visible light wave band is realized, the resolution of 1 [mu] m is achieved, a target can be displayed more clearly, and the spectral confocal dispersion lens is very beneficial to the application of needing to observe tiny details or high-resolution imaging. Compared with an existing dispersion lens, the dispersion lens provided by the invention can collect more light rays by increasing the aperture of the dispersion lens, provides higher light collection capability and increases the brightness of an image.

Description

Technical Field

[0001] The present invention relates to the field of optical technology, and specifically to a large-diameter refractive dispersion lens. Background Art

[0002] The spectral confocal sensor is mainly composed of a dispersion objective lens, a light source and a receiving detector. Its working principle is as follows: Figure 5 As shown. When the object under test is located in the dispersion region, only the light focused on the surface of the object can return to the original path and enter the spectrometer through the pinhole, while the light of other wavelengths (i.e., the light focused at other heights) is blocked by the pinhole. Among the light entering the pinhole, the light energy corresponding to the peak wavelength is the strongest, while the light energy of other wavelengths is relatively weak. Through the calibration information, we can determine the specific position of the object under test based on the peak wavelength.

[0003] The dispersive objective is the core component of the spectral confocal sensor. Its function is to focus light of different wavelengths at different heights in the axial position. The size of its axial chromatic aberration affects the measurement range of the spectral confocal microscope, and the linearity of chromatic aberration with wavelength affects the measurement sensitivity or resolution. Unlike conventional achromatic microscope objectives, dispersive objectives strive to obtain larger axial chromatic aberration. Existing dispersive objectives can be divided into two basic types: refractive and diffractive. They use different principles to achieve the dispersion effect. Refractive dispersive objectives are based on the principle of light refraction in the medium. The most common representative is the prism, which is suitable for situations with a narrow wavelength range. Diffractive dispersive objectives are based on the diffraction phenomenon when light passes through elements such as gratings. They have a wider wavelength adaptability and higher resolution, and are often used in scenes that require processing continuous spectra and high-resolution spectral analysis. Choosing a suitable dispersive objective depends on the requirements of the specific application, including wavelength range, resolution requirements, and the size of the optical system.

[0004] In the existing technical solutions, when using a diffractive dispersion objective lens, an aperture is usually required to limit the size and angle of the incident light to ensure that the grating (or other diffraction element) can work properly and produce the required diffraction effect, which makes the manufacture and calibration of high-performance diffraction objective lenses more complicated and expensive than refractive objective lenses. In addition, the use of the aperture limits the angle of the incident light, resulting in uneven light intensity distribution inside the system, and also introduces aberrations. For example, improper selection of the position of the aperture aperture reduces the clarity and contrast of the image, affecting the image quality.

[0005] The resolution of ordinary dispersive objective lenses ranges from tens to thousands of microns. With the promotion of scientific research, industrial applications and technological progress, the demand for the resolution of dispersive objective lenses is gradually increasing. This trend is mainly due to the urgent need for more precise and accurate optical analysis, as well as the increasing challenges of high-resolution imaging and spectral measurement. Summary of the invention

[0006] The object of the present invention is to provide a large-aperture refractive dispersion lens, which aims to overcome the problems existing in the prior art and can be applied to imaging and observation applications in optical systems. By adopting a refractive dispersion lens, it has a simple structure, is easy to manufacture, has a low cost, improves the resolution of the dispersion lens, and makes the measurement results more precise.

[0007] To achieve the object, the present invention provides the following technical solutions: A large-aperture refractive dispersion lens, which is composed of multiple lens groups and successively includes the following components: The first lens group, which is composed of a first plano-convex lens and two meniscus lenses, is used for focusing light and eliminating spherical aberration and astigmatism; The second lens group, which is composed of a doublet lens and a second plano-convex lens, is used for achromatism correction and correcting spherical aberration and astigmatism of the axial point; The third lens group, which is composed of three single lenses, is used for focusing and introducing different chromatic aberrations to adjust the focal positions of light rays of different wavelengths.

[0008] As a further scheme of the present invention, the two meniscus lenses are respectively a first meniscus lens and a second meniscus lens, along the light propagation direction; the convex surface of the first plano-convex lens faces the image side, the first meniscus lens bends towards the image side, and the second meniscus lens bends towards the object side; the first lens group is jointly composed of the plano-convex lens, the first meniscus lens and the second meniscus lens.

[0009] As a further scheme of the present invention, the focal length of the first lens group is -9.458E+004 mm.

[0010] As a further scheme of the present invention, the ranges of the refractive index and Abbe number of each lens in the first lens group are respectively: For the first plano-convex lens, the refractive index ND1 satisfies 1.75 < ND1 < 1.77, the Abbe number VD1 satisfies 27.5 < VD1 < 27.7, the thickness is 14 mm, and the focal length is 160.6 mm; For the first meniscus lens L2, the refractive index ND2 satisfies 1.75 < ND2 < 1.77, the Abbe number VD2 satisfies 27.5 < VD2 < 27.7, the thickness is 12 mm, and the focal length is -322.3 mm; For the second meniscus lens L3, the refractive index ND3 satisfies 1.75 < ND3 < 1.77, the Abbe number VD3 satisfies 27.5 < VD3 < 27.7, the thickness is 15 mm, and the focal length is -72.5 mm.

[0011] As a further scheme of the present invention, in the second lens group, along the light propagation direction, the plane of the plano-convex lens of the second lens group faces the image side, and the second plano-convex lens and the doublet lens jointly form an achromatic lens group.

[0012] As a further solution of the present invention, the focal length of the achromatic lens group (i.e., the second lens group) is 98.047 mm.

[0013] As a further solution of the present invention, in the second lens group, the doublet lens is composed of lens one and lens two, and the plano-convex lens in the second lens group is composed of lens L6. The refractive index and Abbe number ranges of each lens in the second lens group are as follows: Lens one, the refractive index ND4 satisfies 1.72 < ND4 < 1.74, the Abbe number VD4 satisfies 37.8 < VD4 < 38.0, the thickness is 24 mm, and the focal length is 591.2 mm.

[0014] Lens two: the refractive index ND5 satisfies 1.75 < ND5 < 1.77, the Abbe number VD5 satisfies 27.5 < VD5 < 27.7, the thickness is 10 mm, and the focal length is 250.0 mm.

[0015] The second plano-convex lens, the refractive index ND6 satisfies 1.75 < ND6 < 1.77, the Abbe number VD6 satisfies 27.5 < VD6 < 27.7, the thickness is 12 mm, and the focal length is 200.1 mm.

[0016] As a further solution of the present invention, the three single lenses of the third lens group are respectively a first focusing lens, a second focusing lens, and a third meniscus lens arranged along the light propagation direction, and the three single lenses together form a focusing lens group with a focal length of 70.81 mm.

[0017] As a further solution of the present invention, in the third lens group, the refractive index and Abbe number ranges of the three single lenses are as follows: The third meniscus lens, the refractive index ND7 satisfies 1.74 < ND7 < 1.76, the Abbe number VD7 satisfies 44.8 < VD7 < 45.0, the thickness is 14 mm, and the focal length is -192.7 mm; The first focusing lens, the refractive index ND8 satisfies 1.75 < ND8 < 1.77, the Abbe number VD8 satisfies 27.5 < VD8 < 27.6, the thickness is 12 mm, and the focal length is 97.4 mm; The second focusing lens, the refractive index ND9 satisfies 1.47 < ND9 < 1.49, the Abbe number VD9 satisfies 70.3 < VD9 < 70.5, the thickness is 12 mm, and the focal length is 89.7 mm.

[0018] As a further solution of the present invention, the resolution of this large-aperture refractive dispersion lens reaches 1 μm, and the relative illumination in the full wavelength range of 480 nm - 660 nm is ≥ 99%.

[0019] The present invention has the following beneficial effects compared with the prior art: 1. In the present invention, the first lens group is mainly responsible for eliminating spherical aberration and astigmatism, the second lens group focuses on achromatism and correcting the spherical aberration and astigmatism of the on-axis point, and the third lens group adjusts the focal position of light of different wavelengths by introducing different chromatic aberrations. This staged and targeted aberration correction method enables the entire optical system to more effectively and comprehensively correct various aberrations and improve the imaging quality. The consistent dispersion effect of the entire optical system in a wide wavelength range, that is, it can provide a consistent dispersion effect in a wide wavelength range, which is suitable for processing light of different wavelengths.

[0020] 2. Simple design and easy manufacturing: The design of the dispersion lens is relatively simple and easy to manufacture, which reduces the cost. In addition, it has a higher tolerance to wavefront shape and is more applicable.

[0021] 3. Good focusing effect and high resolution: This dispersion lens can achieve good focusing of light of different wavelengths at different positions and has high resolution, with a minimum resolution of up to 1μm. This enables it to display the target clearly and is suitable for observing tiny details or performing high-resolution imaging.

[0022] 4. Large-aperture design: The dispersion lens has a large aperture, with a maximum aperture of 72.4mm, which is 57.4% larger than the existing dispersion lens. This enables it to collect more light, provide higher light collection capabilities, increase image brightness, and help provide a wider field of view and reduce light spots, which is advantageous for applications that require high focus and reduced aberrations.

[0023] 5. Adapt to large CCD: This dispersion lens can adapt to large CCD, with a maximum of 57.34mm. This provides higher image resolution and is suitable for applications with high requirements for image details. At the same time, the design that adapts to the large target surface helps reduce distortion and improve imaging quality.

[0024] 6. Good relative illumination: The dispersion lens can achieve a relative illumination of more than 99% in the full band range of 480nm-660nm. This is conducive to improving the overall brightness consistency of the image, reducing or eliminating the shadow effect, and improving the image quality.

[0025] In summary, the present invention provides a large-aperture refractive dispersion lens, which has the characteristics of providing consistent dispersion effect in a wide wavelength range, simple design and easy manufacturing, good imaging quality and high light collection capability. The dispersion lens is suitable for processing light from different wavelengths and can achieve good focus and resolution at different wavelengths. The dispersion lens of the present invention also has a larger aperture, can collect more light, and provide a wider field of view and higher image resolution.

[0026] The dispersion lens of the present invention is relatively simple in design, easy to manufacture, and relatively low in cost, and is suitable for large-scale production. It has a certain tolerance for optical systems with non-point sources or non-monochromatic light sources, and can adapt to the needs of different light sources and scenes. In addition, the dispersion lens of the present invention has good relative illumination in the full band range, ensuring that the illumination distribution of the image is more uniform, and improving the overall brightness consistency and quality of the image. This is very important for scenes with high requirements for dispersion and imaging quality in various applications, and has broad application prospects. It can be used in various fields, such as optical microscopes, photographic lenses, astronomical telescopes, etc., to provide high-quality imaging and dispersion effects.

[0027] These and other aspects of the present application will be more concise and understandable in the following description of the embodiments. It should be understood that the above general description and the following detailed description are only exemplary and explanatory and cannot limit the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 FIG. 4 is a schematic diagram of the basic structure of a large-aperture refractive dispersion lens according to an embodiment of the present invention.

[0029] Figure 2 FIG. 4 is a focal shift curve of a large-aperture refractive dispersion lens in a wavelength range of 480 nm to 660 nm according to an embodiment of the present invention.

[0030] Figure 3 1 is a spot diagram of a large-aperture refractive dispersion lens according to an embodiment of the present invention at an operating wavelength of 550 nm.

[0031] Figure 4 This is a relative illumination diagram of the large-aperture refractive dispersion lens according to an embodiment of the present invention at an operating wavelength of 550 nm.

[0032] Figure 5 Schematic diagram of the basic principle of spectral confocal sensor in 2D spectral confocal measurement technology. DETAILED DESCRIPTION

[0033] The specific implementation of the present invention is described below with reference to the accompanying drawings. In order to fully understand the present invention, many details are described below, but for those skilled in the art, the present invention can be implemented without these details.

[0034] It should be noted that all similar expressions such as "first" and "second" in the embodiments of the present invention are used to distinguish two non-identical entities or non-identical parameters with the same name, which is only for the convenience of expression and should not be understood as limiting the embodiments of the present invention. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions.

[0035] See also Figure 1As shown in the figure, an embodiment of the present invention provides a large-aperture refractive dispersion lens, which is composed of multiple lens groups and sequentially includes a first lens group, a second lens group, and a third lens group along the light transmission direction.

[0036] See Figure 1 As shown in the figure, the above-mentioned first lens group is used to focus light and eliminate spherical aberration and astigmatism, and it is composed of a first plano-convex lens L1 and two meniscus lenses.

[0037] In this embodiment, the first plano-convex lens L1 faces the image side, and the two meniscus lenses are respectively a first meniscus lens L2 and a second meniscus lens L3. The first meniscus lens L2 bends towards the image side, and the second meniscus lens L3 bends towards the object side. The first plano-convex lens L1, the first meniscus lens L2, and the second meniscus lens L3 together form a first lens group with a focal length of -9.458E+004 mm.

[0038] In the first lens group, the refractive index and Abbe number ranges of each lens are respectively: For the first plano-convex lens L1, the refractive index ND1 satisfies 1.75 < ND1 < 1.77, the Abbe number VD1 satisfies 27.5 < VD1 < 27.7, the thickness is 14 mm, and the focal length is 160.6 mm; For the first meniscus lens L2, the refractive index ND2 satisfies 1.75 < ND2 < 1.77, the Abbe number VD2 satisfies 27.5 < VD2 < 27.7, the thickness is 12 mm, and the focal length is -322.3 mm; For the second meniscus lens L3, the refractive index ND3 satisfies 1.75 < ND3 < 1.77, the Abbe number VD3 satisfies 27.5 < VD3 < 27.7, the thickness is 15 mm, and the focal length is -72.5 mm.

[0039] Converging effect: The first plano-convex lens L1, as a plano-convex lens, converges light. Its focal length is 160.6 mm, and it is the preliminary focusing element of the entire lens group.

[0040] Divergence and adjustment: The first meniscus lenses L2 and L3 are both meniscus lenses. The focal length of the first meniscus lens L2 is -322.3 mm, and the focal length of the second meniscus lens L3 is -72.5 mm. They are both diverging lenses. They adjust the focusing position and optical path of light through divergence, and combine with the converging effect of the first plano-convex lens L1 to achieve precise control of light focusing.

[0041] Combined effect: When the three lenses are combined together, by reasonably matching their respective focal lengths and positions, the incident parallel light or other light distribution situations can be focused on a specific point, improving the energy density of light and the clarity of imaging.

[0042] Spherical aberration correction: The first lens group corrects spherical aberration by reasonably selecting a combination of lenses with different focal lengths and shapes. The positive focal length of the first plano-convex lens L1 cooperates with the negative focal lengths of the first meniscus lens L2 and the second meniscus lens L3, so that after the light passes through the entire lens group, the light in different regions can converge better near the expected focal point.

[0043] Specific parameter functions: The focal length of the first plano-convex lens L1 is relatively long, which can initially converge the light, while the negative focal lengths of the first meniscus lens L2 and the second meniscus lens L3 can correct the spherical aberration generated by L1. The absolute value of the focal length of the first meniscus lens L2 is relatively large, which can compensate for the spherical aberration of the first plano-convex lens L1 to a certain extent, while the absolute value of the focal length of the second meniscus lens L3 is relatively small, which can further finely adjust the focusing position of the light and reduce the residual spherical aberration.

[0044] Astigmatism correction: The first lens group reduces astigmatism by optimizing the shape, material, and combination method of the lenses. In the first lens group, the first plano-convex lens L1, the first meniscus lens L2, and the second meniscus lens L3 all adopt specific meniscus or plano-convex shapes, which help to improve the refraction of light in different directions.

[0045] Parameter influence: The plano-convex shape of the first plano-convex lens L1 can converge the light more uniformly, reducing the difference in light in different directions. The meniscus shapes of the first meniscus lens L2 and the second meniscus lens L3 can further adjust the focusing characteristics of the light in different directions, improving the imaging quality of off-axis light, thereby effectively eliminating astigmatism. At the same time, the refractive indices and Abbe numbers of each lens are similar, which helps to keep the propagation characteristics of the light in the lens group consistent and further reduce the generation of astigmatism.

[0046] See Figure 1 As shown, the above second lens group is used for achromatism correction and correction of spherical aberration and astigmatism of the on-axis point, and it is composed of a doublet lens and a second plano-convex lens L6.

[0047] In this embodiment, the plane of the second plano-convex lens L6 faces the image side, and the doublet lens is composed of lens one L4 and lens two L5. The achromatic lens group (i.e., the second lens group) with a focal length of 98.047 mm is jointly composed of lens one L4, lens two L5, and the second plano-convex lens L6.

[0048] In the second lens group, the ranges of the refractive index and Abbe number of each lens are as follows: For lens one L4, the refractive index ND4 satisfies 1.72 < ND4 < 1.74, the Abbe number VD4 satisfies 37.8 < VD4 < 38.0, the thickness is 24 mm, and the focal length is 591.2 mm.

[0049] Lens two L5 has a refractive index ND5 satisfying 1.75 < ND5 < 1.77, an Abbe number VD5 satisfying 27.5 < VD5 < 27.7, a thickness of 10 mm, and a focal length of 250.0 mm.

[0050] The second plano-convex lens L6 has a refractive index ND6 satisfying 1.75 < ND6 < 1.77, an Abbe number VD6 satisfying 27.5 < VD6 < 27.7, a thickness of 12 mm, and a focal length of 200.1 mm.

[0051] Function of the doublet lens: It is a combination of positive and negative lenses. The different refractive indices and dispersion characteristics of different wavelengths of light can be used to cancel chromatic aberration. Specifically, lens one L4, as a positive lens, converges light, while lens two L5, as a negative lens, diverges light. By reasonably selecting the materials and curvatures of these two lenses, they produce opposite chromatic aberration effects on different wavelengths of light within the visible spectrum range, thus achieving the cancellation of chromatic aberration as a whole.

[0052] Auxiliary function of the second plano-convex lens L6: The refractive index ND6 and Abbe number VD6 of the second plano-convex lens L6 are similar to those of lens two L5, and its plane faces the image side. This design helps to further adjust the focusing characteristics of light and chromatic aberration compensation. The addition of the second plano-convex lens L6 can optimize the optical power distribution of the entire lens group without introducing additional chromatic aberration, making the correction effect of chromatic aberration more accurate and stable.

[0053] Spherical aberration correction of the doublet lens: The doublet lens not only plays a role in achromatism but also can correct spherical aberration by reasonably designing the curvatures and thicknesses of the positive and negative lenses. The combination of lens one L4 and lens two L5 enables different regions of light to converge better near the expected focal point when passing through the lens group, reducing the generation of spherical aberration. Specifically, the positive focal length of lens one L4 and the negative focal length of lens two L5 cooperate with each other to adjust the focusing position of light in the lens, making the intersection of marginal rays and central rays closer, thereby reducing spherical aberration.

[0054] Influence of lens shape and combination: The shapes and combination methods of lens one L4, lens two L5, and the second plano-convex lens L6 play a key role in the correction of astigmatism. As a doublet lens, the combination of lens one L4 and lens two L5, with its positive and negative lenses, can improve the refraction of light in different directions and reduce the generation of astigmatism. The plano-convex shape of the second plano-convex lens L6 further optimizes the focusing characteristics of off-axis light, enabling the meridional image and sagittal image of off-axis light to better coincide on the same imaging plane, thus effectively eliminating astigmatism.

[0055] Synergy of parameters: The reasonable combination of parameters such as the refractive index, Abbe number, and focal length of each lens is also an important factor in correcting astigmatism. The differences in the refractive index and Abbe number between the first lens L4 and the second lens L5 enable them to produce different astigmatism effects during the propagation of light. By reasonably adjusting their focal lengths and positions, these astigmatism effects can be offset against each other. The parameters of the second plano-convex lens L6 further optimize the light propagation characteristics of the entire lens group, making the correction effect of astigmatism more significant.

[0056] See Figure 1 As shown, the above-mentioned third lens group is used for focusing and introducing different chromatic aberrations to adjust the focal positions of light rays of different wavelengths, and is composed of three single lenses.

[0057] In this embodiment, the third lens group is composed of a third meniscus lens L7, a first focusing lens L7, a first focusing lens L8, and a second focusing lens L9 arranged along the light propagation direction. These three single lenses together form a focusing lens group (i.e., the third lens group) with a focal length of 70.81 mm.

[0058] In the third lens group, the ranges of the refractive index and Abbe number of each single lens are as follows: Third meniscus lens L7: The refractive index ND7 satisfies 1.74 < ND7 < 1.76, the Abbe number VD7 satisfies 44.8 < VD7 < 45.0, the thickness is 14 mm, and the focal length is -192.7 mm; First focusing lens L8: The refractive index ND8 satisfies 1.75 < ND8 < 1.77, the Abbe number VD8 satisfies 27.5 < VD8 < 27.6, the thickness is 12 mm, and the focal length is 97.4 mm; Second focusing lens L9: The refractive index ND9 satisfies 1.47 < ND9 < 1.49, the Abbe number VD9 satisfies 70.3 < VD9 < 70.5, the thickness is 12 mm, and the focal length is 89.7 mm.

[0059] Optical power adjustment of the lens combination: The focal lengths of the third meniscus lens L7, the first focusing lens L8, and the second focusing lens L9 are -192.7 mm, 97.4 mm, and 89.7 mm respectively. By reasonably combining these lenses, the overall optical power of the entire lens group can be adjusted. The adjustment of the optical power changes the degree of convergence or divergence of light rays, thereby achieving the adjustment of the focal position. In practical applications, by moving the positions of these lenses along the light propagation direction, the focal position can be further finely adjusted. For example, moving the first focusing lens L8 and the second focusing lens L9 can change the focusing situation of the light rays passing through the lens group, making the focal point move within a certain range to achieve the purpose of precise focusing.

[0060] Differences in the dispersion characteristics of materials: The Abbe number VD7 of the third meniscus lens L7 is between 44.8 and 45.0, the Abbe number VD8 of the first focusing lens L8 is between 27.5 and 27.6, and the Abbe number VD9 of the second focusing lens L9 is between 70.3 and 70.5. Different Abbe numbers mean that these lenses have different changes in the refractive index for light of different wavelengths, that is, they have different dispersion characteristics. By combining these lenses with different dispersion characteristics, different chromatic aberrations can be introduced. Specifically, the Abbe numbers of the third meniscus lens L7 and the first focusing lens L8 are relatively low, and the dispersion of light is large, while the Abbe number of the second focusing lens L9 is higher and the dispersion is small. When light passes through the third lens group, the differences in the dispersion characteristics of these lenses will cause light of different wavelengths to have different degrees of chromatic aberration. By adjusting the position and combination of each lens, this chromatic aberration can be controlled and adjusted so that light of different wavelengths is focused at different focal positions.

[0061] The specific parameters of this embodiment are shown in Table 1: Table 1. Optical system parameters of the lens

[0062] Table 2. Optical parameters of the lens

[0063] Table 3. Lens spacing parameters

[0064] See also Figure 2 As shown, Figure 2 This is the focal shift curve of the dispersion lens in the 480nm to 660nm band, which shows the relationship between the wavelength and the focal position in the 480nm to 660nm working band.

[0065] See also Figure 3 and Figure 4 As shown, Figure 3 This is the spot diagram of the dispersion lens at a working wavelength of 550nm. The RMS radius of each field of view in the spot diagram is within 1μm, and the focusing effect is good. This means that the resolution of the lens can reach 1μm, which can achieve more accurate optical analysis. Figure 4 This is a relative illumination diagram. The maximum relative illumination reaches 1.0, and the relative illumination of the lens imaging is close to 100%.

[0066] It can be seen that the resolution of the large-aperture refractive dispersion lens proposed in the present invention reaches 1 μm, the relative illumination in the full band range of 480nm-660nm is ≥99%, and the illumination at each field point of the system is uniform, which is conducive to maintaining consistent image quality in the entire field of view and improving image quality.

[0067] Compared with the prior art, the large-aperture refractive dispersion lens of the present invention has many advantages as a refractive dispersion objective lens, which makes it widely used in optical systems. The main advantages include providing a consistent dispersion effect in a wide wavelength range, which makes the dispersion lens of the present invention suitable for systems that process light from different wavelengths; the refractive dispersion lens of the present invention uses optical elements such as prisms, which are simple in design, easy to manufacture, relatively low in cost, and easier to achieve large-scale production; at the same time, the refractive dispersion lens is more tolerant to the wavefront shape of the incident light. Compared with some other dispersion elements, it is more tolerant to optical systems with non-point sources or non-monochromatic light sources, and enhances its applicability under non-point sources or non-monochromatic light sources.

[0068] Moreover, the large-aperture refractive dispersion lens of the present invention has good focusing effect and high resolution. On the premise of meeting the basic requirements of the spectral confocal dispersion lens, good focusing of light of different wavelengths at different positions is achieved in the visible light band, and a resolution of 1μm is achieved at the same time, which can display the target more clearly, and is very beneficial for applications that require observation of tiny details or high-resolution imaging. Compared with the existing dispersion lens, the large-aperture dispersion lens provided by the present invention, such as the Chinese invention patent CN115469433A discloses a dispersion lens (see the document: Suzhou University. A spectral confocal displacement sensor dispersion lens: CN202211168615.6.2022-12-13.), has a maximum aperture of 46mm. The large-aperture dispersion lens provided by the present invention has a maximum aperture of 72.4mm, which is an increase of 57.4%. By increasing the aperture of the dispersion lens, more light can be collected.

[0069] Therefore, the light collection capability of the dispersion lens proposed in the present invention is 2.48 times that of the lens disclosed in patent CN115469433A. For the optical system, especially under low light conditions, it can provide higher light collection capability and increase the brightness of the image. At the same time, it helps to provide a wider field of view and form a smaller light spot, which is advantageous for some applications that require high focus and reduced aberrations.

[0070] In addition, the dispersion lens provided by the present invention is adapted to a large-surface CCD, and can be adapted to a CCD surface of up to 57.34 mm. Adapting the lens to a large-surface CCD can bring the following advantages: First, a larger field of view enables the camera system to capture a wider scene, which is suitable for applications that require a wide-angle field of view or cover a large area. Second, a large-surface CCD provides a higher image resolution, which is essential for applications that require high image details; a design that adapts to a large-surface CCD helps reduce lens distortion and improve image quality.

[0071] Moreover, the dispersion lens provided by the present invention can achieve a relative illumination of more than 99% in the full band range of 480nm-660nm, and has good relative illumination, which is conducive to ensuring that the illumination distribution of the image at different positions in the field of view is more uniform, thereby improving the overall brightness consistency of the image, and helping to reduce or eliminate the shadow effect in the image, which is particularly important for scenes with strict requirements on illumination uniformity such as medical imaging and industrial detection. It also helps to improve the quality of the image and provide clearer and more accurate imaging performance for various applications.

[0072] The above is only a specific implementation of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantial changes to the present invention using this concept shall be deemed as an infringement of the protection scope of the present invention.

Claims

1. A large-aperture refractive dispersion lens, characterized in that: 依次包括以下组件: The first lens group, which consists of a first plano-convex lens (L1), a first meniscus lens (L2), and a second meniscus lens (L3), is used to focus light and eliminate spherical aberration and astigmatism. The second lens group, which consists of a doublet lens and a second plano-convex lens (L6), and the plane of the second plano-convex lens (L6) faces the image side, is used to correct chromatic aberration and correct spherical aberration and astigmatism of the axial point. The third lens group, which consists of a first focusing lens (L7), a second focusing lens (L8), and a third meniscus lens (L9), is used for focusing and introducing different chromatic aberrations to adjust the focal positions of light rays of different wavelengths.

2. The large-aperture refractive dispersion lens according to claim 1, characterized in that: Along the light propagation direction, the convex surface of the first plano-convex lens (L1) faces the image side, the first meniscus lens (L2) bends towards the image side, and the second meniscus lens (L3) bends towards the object side.

3. The large-aperture refractive dispersion lens according to claim 2, characterized in that: The focal length of the first lens group is -9.458E+004 mm.

4. The large-aperture refractive dispersion lens according to claim 3, characterized in that: The first lens group satisfies the following conditions: The first plano-convex lens (L1), with refractive index ND1 satisfying 1.75 < ND1 < 1.77 and Abbe number VD1 satisfying 27.5 < VD1 < 27.7; the thickness is 14 mm; the focal length is 160.6 mm. The first meniscus lens (L2), with refractive index ND2 satisfying 1.75 < ND2 < 1.77 and Abbe number VD2 satisfying 27.5 < VD2 < 27.7, the thickness is 12 mm, and the focal length is -322.3 mm. The second meniscus lens (L3), with refractive index ND3 satisfying 1.75 < ND3 < 1.77 and Abbe number VD3 satisfying 27.5 < VD3 < 27.7, the thickness is 15 mm, and the focal length is -72.5 mm.

5. The large-aperture refractive dispersion lens according to claim 4, characterized in that: The focal length of the second lens group is 98.047 mm.

6. The large-aperture refractive dispersion lens according to claim 5, characterized in that: In the second lens group, the doublet lens consists of a lens one (L4) and a lens two (L5); the second lens group satisfies the following conditions: Lens one (L4), with refractive index ND4 satisfying 1.72 < ND4 < 1.74 and Abbe number VD4 satisfying 37.8 < VD4 < 38.0, the thickness is 24 mm, and the focal length is 591.2 mm. Lens two (L5), with refractive index ND5 satisfying 1.75 < ND5 < 1.77 and Abbe number VD5 satisfying 27.5 < VD5 < 27.7, the thickness is 10 mm, and the focal length is 250.0 mm. The second plano-convex lens (L6): with refractive index ND6 satisfying 1.75 < ND6 < 1.77 and Abbe number VD6 satisfying 27.5 < VD6 < 27.7, the thickness is 12 mm, and the focal length is 200.1 mm.

7. The large-aperture refractive dispersion lens according to claim 6, characterized in that: The focal length of the third lens group is 70.81 mm.

8. The large-aperture refractive dispersion lens according to claim 7, characterized in that: The third lens group satisfies the following conditions: The third meniscus lens (L7), with refractive index ND7 satisfying 1.74 < ND7 < 1.76 and Abbe number VD7 satisfying 44.8 < VD7 < 45.0, the thickness is 14 mm, and the focal length is -192.7 mm. The first focusing lens (L8), with refractive index ND8 satisfying 1.75 < ND8 < 1.77 and Abbe number VD8 satisfying 27.5 < VD8 < 27.6, the thickness is 12 mm, and the focal length is 97.4 mm. The second focusing lens (L9) has a refractive index ND9 satisfying 1.47 < ND9 < 1.49 and an Abbe number VD9 satisfying 70.3 < VD9 < 70.5, a thickness of 12 mm, and a focal length of 89.7 mm.

9. The large-aperture refractive dispersion lens according to claim 8, characterized in that: The resolution of this large-aperture refractive dispersion lens reaches 1 μm, and the relative illumination in the full wavelength range of 480 nm - 660 nm is ≥ 99%.

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