An optical lens

Abstract

The application discloses an optical lens, which comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens and a ninth lens arranged in sequence along an optical axis from an object plane to an image plane, wherein the first lens has a negative focal power, the second lens has a positive focal power, the third lens has a negative focal power, the fourth lens has a positive focal power, the fifth lens has a positive focal power, the sixth lens has a negative focal power, the seventh lens has a positive focal power, the eighth lens has a positive focal power, the ninth lens has a negative focal power, and the nine lenses are all glass spherical lenses. The optical lens provided by the embodiment of the application has the advantages of simple and compact structure, strong environmental adaptability, an aperture number FNO of less than or equal to 2.0, high resolving power, and the like, can match a 1 / 1.7 inch chip, and realizes a full-glass optical lens with a large target surface, high definition, and day and night confocal.

Description

Technical Field

[0001] This invention relates to the field of optical technology, and more particularly to an optical lens. Background Technology

[0002] With the advancement of the security monitoring industry, closed-circuit monitoring is trending towards miniaturization, multi-functionality, strong environmental adaptability, and high-definition imaging.

[0003] Conventional glass-plastic hybrid lenses cannot meet the temperature adaptability requirements of different geographical environments. Furthermore, based on the current and future development needs of ultra-high-definition surveillance systems, most lenses with 4K and higher resolution on the market use aspherical elements, undoubtedly increasing lens development costs. At the same time, the image sensor size of lenses on the market is generally small. Summary of the Invention

[0004] This invention provides an optical lens to achieve a large target area, high definition, and day and night confocal optical lens.

[0005] This invention provides an optical lens, comprising a first lens group and a second lens group arranged sequentially along the optical axis from the object plane to the image plane; The first lens group includes a first lens, a second lens, a third lens, and a fourth lens arranged sequentially along the optical axis from the object plane to the image plane; The second lens group includes a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens arranged sequentially along the optical axis from the object plane to the image plane; The first lens has negative optical power, the second lens has positive optical power, the third lens has negative optical power, the fourth lens has positive optical power, the fifth lens has positive optical power, the sixth lens has negative optical power, the seventh lens has positive optical power, the eighth lens has positive optical power, and the ninth lens has negative optical power. The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, and the ninth lens are all glass spherical lenses.

[0006] Optionally, the fifth lens and the sixth lens form a first cemented lens group; and / or, the eighth lens and the ninth lens form a second cemented lens group.

[0007] Optionally, the optical power of the optical lens is Φeff, the optical power of the first lens group is ΦA, and the optical power of the second lens group is ΦB, wherein -5.50 < Φeff / ΦA < 15.50, 0.85 < Φeff / ΦB < 3.25, and -0.95 < ΦA / ΦB < 0.55.

[0008] Optionally, the optical lens may also include an aperture stop; The aperture is located in the optical path between the first lens group and the second lens group.

[0009] Optionally, the focal length of the optical lens is f, and the entrance pupil diameter of the optical lens is D, wherein 1.35≤f / D≤2.0.

[0010] Optionally, the total optical length of the optical lens is TTL, and the focal length of the optical lens is f, wherein 3.45≤TTL / f≤6.55.

[0011] Optionally, the total optical length of the optical lens is TTL, wherein 30.0mm≤TTL≤40.0mm.

[0012] Optionally, the half-image height of the optical lens is Imah, and the focal length of the optical lens is f, wherein 0.55 ≤ Imah / f ≤ 0.75.

[0013] Optionally, the optical back focal length of the optical lens is OBFL, and the total optical length of the optical lens is TTL, wherein 0.15≤OBFL / TTL≤0.35.

[0014] The optical lens provided in this invention consists of nine standard spherical glass lenses. The number of lenses is reasonable, resulting in a simple and compact structure with a total optical length not exceeding 40mm. Simultaneously, glass lenses have higher transmittance, reducing light energy loss and allowing the image sensor to receive higher light energy. The use of glass lenses for all nine lenses also provides advantages such as high hardness, strong wear resistance, long service life, and resistance to temperature-induced deformation, leading to more stable performance and stronger environmental adaptability. Furthermore, the use of spherical lenses for all nine helps reduce the manufacturing cost of glass lenses, achieving cost control for the optical lens. By rationally allocating optical power and combining it with the glass material, day and night co-focusing is achieved, maintaining focus in environments ranging from -40℃ to +85℃, demonstrating strong environmental adaptability. The reasonable optical power and position of each lens result in an aperture number (FNO) ≤ 2.0, high resolution, and the ability to meet ultra-high-definition imaging requirements. Meanwhile, the optical lens can be matched with a 1 / 1.7-inch chip. The large target surface design has better imaging performance under the same field of view, realizing a large target surface, high definition, day and night confocal all-glass optical lens.

[0015] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of an optical lens provided in an embodiment of the present invention; Figure 2 This is a spherical aberration curve of an optical lens provided in Embodiment 1 of the present invention; Figure 3 This is a ray fan pattern of an optical lens provided in Embodiment 1 of the present invention; Figure 4 This is a field curvature distortion diagram of an optical lens provided in Embodiment 1 of the present invention; Figure 5 This is a schematic diagram of the structure of the optical lens provided in Embodiment 2 of the present invention; Figure 6 This is a spherical aberration curve of the optical lens provided in Embodiment 2 of the present invention; Figure 7 This is a ray fan pattern of the optical lens provided in Embodiment 2 of the present invention; Figure 8 This is a field curvature distortion diagram of an optical lens provided in Embodiment 2 of the present invention; Figure 9 This is a schematic diagram of the structure of the optical lens provided in Embodiment 3 of the present invention; Figure 10 This is a spherical aberration curve of the optical lens provided in Embodiment 3 of the present invention; Figure 11 This is a ray fan pattern of the optical lens provided in Embodiment 3 of the present invention; Figure 12 This is a field curvature distortion diagram of the optical lens provided in Embodiment 3 of the present invention; Figure 13 This is a schematic diagram of the structure of the optical lens provided in Embodiment 4 of the present invention; Figure 14 This is a spherical aberration curve of the optical lens provided in Embodiment 4 of the present invention; Figure 15 This is a ray fan pattern of the optical lens provided in Embodiment 4 of the present invention; Figure 16 This is a field curvature distortion diagram of an optical lens provided in Embodiment 4 of the present invention. Detailed Implementation

[0018] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. 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.

[0019] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention 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 so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a 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.

[0020] Figure 1 This is a schematic diagram of the structure of an optical lens provided in an embodiment of the present invention, such as... Figure 1 As shown, the optical lens provided in this embodiment of the invention includes a first lens group 10 and a second lens group 20 arranged sequentially along the optical axis from the object plane to the image plane. The first lens group 10 includes a first lens 101, a second lens 102, a third lens 103, and a fourth lens 104 arranged sequentially along the optical axis from the object plane to the image plane. The second lens group 20 includes a fifth lens 201, a sixth lens 202, a seventh lens 203, an eighth lens 204, and a ninth lens 205 arranged sequentially along the optical axis from the object plane to the image plane. The first lens 101 has negative optical power, the second lens 102 has positive optical power, the third lens 103 has negative optical power, the fourth lens 104 has positive optical power, the fifth lens 201 has positive optical power, the sixth lens 202 has negative optical power, the seventh lens 203 has positive optical power, the eighth lens 204 has positive optical power, and the ninth lens 205 has negative optical power. The first lens 101, the second lens 102, the third lens 103, the fourth lens 104, the fifth lens 201, the sixth lens 202, the seventh lens 203, the eighth lens 204 and the ninth lens 205 are all glass spherical lenses.

[0021] Specifically, optical power is equal to the difference between the convergence of the image-side beam and the convergence of the object-side beam; it characterizes the ability of an optical system to deflect light. The larger the absolute value of the optical power, the stronger its ability to bend light; the smaller the absolute value, the weaker its ability to bend light. When the optical power is positive, the refraction of light is converging; when the optical power is negative, the refraction of light is diverging. Optical power can be used to characterize a single refractive surface of a lens (i.e., one surface of the lens), a single lens, or a system formed by multiple lenses (i.e., a lens group).

[0022] In the optical lens provided in this embodiment, each lens can be fixed in a lens barrel. Figure 1 (Not shown in the text) but not limited to this.

[0023] The optical lens consists of nine standard spherical glass lenses. The number of lenses is reasonable, resulting in a simple and compact structure with a total optical length not exceeding 40mm. Furthermore, glass lenses offer higher transmittance, reducing light energy loss and allowing the image sensor to receive more light. The use of glass lenses for all nine also provides advantages such as high hardness, strong wear resistance, long service life, and resistance to temperature-induced deformation, leading to more stable performance and stronger environmental adaptability. Moreover, the use of spherical lenses for all nine contributes to reducing the manufacturing cost of the glass lenses, thus achieving cost control for the optical lens.

[0024] It should be noted that the glass spherical lens described above is made of various types of glass materials known to those skilled in the art, and the embodiments of the present invention will not elaborate on or limit this.

[0025] Furthermore, the optical power of the first lens 101, second lens 102, third lens 103, fourth lens 104, fifth lens 201, sixth lens 202, seventh lens 203, eighth lens 204, and ninth lens 205 adopts a negative-positive-negative-positive-positive-negative-positive-positive-negative combination. Combined with the glass material, it can achieve day and night confocal focus and remain in focus under environmental conditions of -40℃ to +85℃, exhibiting strong environmental adaptability. The reasonable optical power and position of each lens result in an aperture number (FNO) ≤ 2.0, high resolution, and the ability to meet ultra-high-definition imaging requirements. Simultaneously, this optical lens can be matched with a 1 / 1.7-inch chip; the large target surface design provides superior imaging performance within the same viewing angle range, achieving a large target surface, high definition, and day-and-night confocal all-glass optical lens.

[0026] As one possible implementation method, please refer to [reference]. Figure 1The fifth lens 201 and the sixth lens 202 form the first cemented lens group 31; and / or the eighth lens 204 and the ninth lens 205 form the second cemented lens group 32.

[0027] By setting the fifth lens 201 and the sixth lens 202 to form the first cemented lens group 31, a large target area, high definition, and day / night confocal focusing are achieved while minimizing or eliminating chromatic aberration, thus ensuring sufficient correction of chromatic aberration in the optical lens. Simultaneously, the air gap between the fifth lens 201 and the sixth lens 202 is effectively reduced, further decreasing the overall length of the lens. Furthermore, cementing the fifth lens 201 and the sixth lens 202 reduces the number of assembly components, simplifying the assembly process in lens manufacturing, lowering costs, and reducing tolerance sensitivity issues such as tilting / eccentricity that occur during lens assembly.

[0028] By setting the eighth lens 204 and the ninth lens 205 to form the second cemented lens group 32, a large target area, high resolution, and day / night confocal focusing are achieved while minimizing or eliminating chromatic aberration, ensuring sufficient correction of chromatic aberration in the optical lens. Simultaneously, the air gap between the eighth lens 204 and the ninth lens 205 is effectively reduced, further decreasing the overall lens length. Furthermore, cementing the eighth lens 204 and the ninth lens 205 reduces the number of assembly components, simplifying the assembly process in lens manufacturing, lowering costs, and reducing tolerance sensitivity issues such as tilting / eccentricity that occur during lens assembly.

[0029] As a feasible implementation, the optical power of the optical lens is Φeff, the optical power of the first lens group 10 is ΦA, and the optical power of the second lens group 20 is ΦB, wherein -5.50 < Φeff / ΦA < 15.50, 0.85 < Φeff / ΦB < 3.25, and -0.95 < ΦA / ΦB < 0.55.

[0030] By allocating the optical power of each lens group reasonably, a large target area, high definition, and day and night confocality can be achieved while effectively correcting aberrations and reducing tolerance sensitivity.

[0031] As one possible implementation method, please refer to [reference]. Figure 1 The optical lens also includes an aperture stop 40, which is located in the optical path between the first lens group 10 and the first lens group 20.

[0032] The aperture 40 can adjust the propagation direction of the light beam. By setting the aperture 40 in the optical path between the first lens group 10 and the second lens group 20, the optical lens can have a smaller distortion value on the one hand, and can also achieve a large aperture effect on the other hand, increasing the amount of light entering the optical lens and achieving higher image quality.

[0033] As a feasible implementation method, the focal length of the optical lens is f, and the entrance pupil diameter of the optical lens is D, where 1.35≤f / D≤2.0.

[0034] The entrance pupil diameter of the optical lens can refer to the aperture value of the aperture 40 imaged by the first lens group 10. By further setting the focal length f and entrance pupil diameter D of the optical lens to satisfy 1.35≤f / D≤2.0, the optical lens can have a smaller distortion value. At the same time, the optical lens can also achieve a large aperture effect, increase the amount of light entering the optical lens, and achieve higher image quality.

[0035] As a feasible implementation method, the total optical length of the optical lens is TTL, and the focal length of the optical lens is f, where 3.45≤TTL / f≤6.55.

[0036] The total optical length (TTL) of the optical lens refers to the distance from the center of the optical axis of the object side surface of the first lens 101 to the image plane. The object side surface refers to the surface of the lens adjacent to the object plane.

[0037] In this embodiment, by setting the total optical length (TTL) and focal length (f) of the optical lens to satisfy 3.45≤TTL / f≤6.55, the optical lens structure can be made compact and have a smaller volume.

[0038] As a feasible implementation method, the total optical length of the optical lens is TTL, where 30.0mm≤TTL≤40.0mm.

[0039] The optical lens provided in this embodiment has an optical total length (TTL) of no more than 40mm, a compact structure, and a smaller volume.

[0040] As a feasible implementation method, the half-image height of the optical lens is Imah, and the focal length of the optical lens is f, where 0.55≤ImaH / f≤0.75.

[0041] By setting the half-image height Imah and focal length f of the optical lens to satisfy 0.55≤ImaH / f≤0.75, the optical lens can achieve a large target surface design effect, which can be matched with a 1 / 1.7-inch chip, thus achieving better imaging performance under the same viewing angle range.

[0042] As a feasible implementation method, the optical back focal length of the optical lens is OBFL, and the total optical length of the optical lens is TTL, wherein 0.15≤OBFL / TTL≤0.35.

[0043] By setting the optical back focal length (OBFL) and total optical length (TTL) of the optical lens to satisfy 0.15≤OBFL / TTL≤0.35, the optical lens structure is compact while having a longer optical back focal length, which helps to ensure that structures such as filters have sufficient installation space.

[0044] As one possible implementation method, please refer to [reference]. Figure 1 The optical lens also includes a filter 50, located on the image-side side of the ninth lens 205. The filter 50 filters out unwanted stray light, thereby improving the image quality of the optical lens and ensuring good imaging performance both day and night. For example, the filter 50 can filter out infrared light during the day to improve the image quality. Simultaneously, the filter 50 also protects the imaging sensor.

[0045] The image side refers to the surface of the lens adjacent to the image plane.

[0046] In summary, the optical lens provided by the embodiments of the present invention, through reasonable combination of various lens materials and optical power, can effectively correct various aberrations, reduce distortion, achieve day and night confocal focus, reach 4K resolution, and has a compact lens structure, significantly reduced tolerance sensitivity, stable lens performance, and does not defocus in environmental conditions of -40℃ to +85℃, thus having good environmental adaptability.

[0047] Specific embodiments of the optical lens applicable to the above-described embodiments are further described below with reference to the accompanying drawings.

[0048] Example 1 Continue to refer to Figure 1 The optical lens provided in Embodiment 1 of the present invention includes a first lens group 10 and a second lens group 20 arranged sequentially along the optical axis from the object plane to the image plane. The first lens group 10 includes a first lens 101, a second lens 102, a third lens 103, and a fourth lens 104 arranged sequentially along the optical axis from the object plane to the image plane. The second lens group 20 includes a fifth lens 201, a sixth lens 202, a seventh lens 203, an eighth lens 204, and a ninth lens 205 arranged sequentially along the optical axis from the object plane to the image plane. The fifth lens 201 and the sixth lens 202 form a first cemented lens group 31, and the eighth lens 204 and the ninth lens 205 form a second cemented lens group 32. An aperture stop 40 is located in the optical path between the first lens group 10 and the first lens group 20. A filter 50 is located on the image-side side of the ninth lens 205.

[0049] Table 1 details the specific optical physical parameters of each lens in the optical lens provided in Embodiment 1 of the present invention, using a feasible implementation method. The optical lenses in Table 1 correspond to... Figure 1 The optical lens shown.

[0050] Table 1 Design values ​​of optical physical parameters of optical lenses

[0051] In Table 1, the surface numbers are assigned according to the surface sequence of each lens. For example, surface number "S1" represents the object-side surface of the first lens, surface number "S2" represents the image-side surface of the first lens, and so on. "STO" represents the aperture stop of the optical lens; "OBJ" represents the object plane; "IMA" represents the image plane; the radius of curvature represents the curvature of the lens surface, with a positive value indicating that the surface bends towards the image plane and a negative value indicating that the surface bends towards the object plane. "Infinity" indicates that the surface is flat and the radius of curvature is infinite; the thickness represents the central axial distance between the current surface and the next surface; the refractive index (Nd) represents the ability of the material between the current surface and the next surface to deflect light, with a blank space indicating that the current position is air and the refractive index is 1; the Abbe number (Vd) represents the dispersion characteristics of the material between the current surface and the next surface, with a blank space indicating that the current position is air; and half-aperture represents the effective ray diameter of the lens.

[0052] The optical lens provided in this embodiment achieves the following technical specifications: The focal length f is 7.94mm, the aperture F# is 2.0, the field of view DFOV is 74.0°, and the total optical length TTL is 39.09mm.

[0053] Furthermore, Figure 2 This is a spherical aberration curve diagram of an optical lens provided in Embodiment 1 of the present invention. In the diagram, the vertical direction represents the normalized aperture, 0 indicates it is on the optical axis, the vertical vertex represents the maximum pupil radius, and the horizontal direction represents the offset relative to the ideal focal point, in millimeters (mm). Different linear curves in the diagram represent different wavelengths of image formation by the optical lens. Figure 2 It can be seen that the pupil radius is 1.9855mm, and the axial aberrations at different wavelengths (0.436μm, 0.486μm, 0.546μm, 0.587μm, 0.656μm and 0.850μm) are all controlled within the range of (-0.05mm, +0.05mm), indicating that the spherical aberration of the optical lens is well controlled at each wavelength.

[0054] Figure 3This is a ray fan diagram of an optical lens provided in Embodiment 1 of the present invention. The ray fan diagram is one of the most commonly used evaluation methods in modern optical design. In the diagram, the horizontal axis represents the beam aperture, and the vertical axis represents the transverse aberration. Ideally, all curves coincide with a straight line on the horizontal axis, indicating that all rays converge at the same point on the image plane. The interval corresponding to the vertical axis of the curve represents the maximum dispersion range of the beam on the ideal image plane. The ray fan diagram can reflect not only monochromatic aberrations of different wavelengths but also the magnitude of transverse chromatic aberration. Figure 3 It can be seen that the optical lens closely approximates the horizontal axis at each wavelength in each field of view, indicating that the transverse aberration of each wavelength is well corrected. At the same time, there is no obvious dispersion of each wavelength, indicating that the chromatic aberration of the optical lens is also well corrected, thus ensuring that the optical lens can achieve the high-resolution imaging requirements.

[0055] Figure 4 This is a field curvature distortion diagram of an optical lens provided in Embodiment 1 of the present invention. In the coordinate system on the left side of the diagram, the horizontal coordinate represents the magnitude of the field curvature, in millimeters (mm); the vertical coordinate represents the normalized image height, which has no unit; solid lines represent meridion, and dashed lines represent arc distortion; from Figure 4 It can be seen that the optical lens provided in this embodiment effectively controls the field curvature of light with wavelengths from 436nm to 850nm, meaning that during imaging, the difference in image quality between the center and the periphery is small; in the coordinate system on the right, the horizontal axis represents the magnitude of F-Tan (Theta) distortion, in %; the vertical axis represents the normalized image height, which has no unit; from Figure 4 It can be seen that the optical lens provided in this embodiment has achieved good distortion correction in the wavelength range of 436nm to 850nm.

[0056] Example 2 Figure 5 This is a schematic diagram of the structure of the optical lens provided in Embodiment 2 of the present invention, as shown below. Figure 5 As shown, the optical lens provided in Embodiment 2 of the present invention includes a first lens group 10 and a second lens group 20 arranged sequentially along the optical axis from the object plane to the image plane. The first lens group 10 includes a first lens 101, a second lens 102, a third lens 103, and a fourth lens 104 arranged sequentially along the optical axis from the object plane to the image plane. The second lens group 20 includes a fifth lens 201, a sixth lens 202, a seventh lens 203, an eighth lens 204, and a ninth lens 205 arranged sequentially along the optical axis from the object plane to the image plane. The fifth lens 201 and the sixth lens 202 form a first cemented lens group 31, and the eighth lens 204 and the ninth lens 205 form a second cemented lens group 32. An aperture stop 40 is located in the optical path between the first lens group 10 and the first lens group 20. A filter 50 is located on the image side of the ninth lens 205.

[0057] Table 2 describes in detail the specific optical physical parameters of each lens in the optical lens provided in Embodiment 2 of the present invention, according to a feasible implementation method.

[0058] Table 2 Design values ​​of optical physical parameters of optical lenses

[0059] In Table 2, the surface numbers are assigned according to the surface sequence of each lens. For example, surface number "S1" represents the object-side surface of the first lens, surface number "S2" represents the image-side surface of the first lens, and so on. "STO" represents the aperture stop of the optical lens; "OBJ" represents the object plane; "IMA" represents the image plane; the radius of curvature represents the curvature of the lens surface, with a positive value indicating that the surface bends towards the image plane and a negative value indicating that the surface bends towards the object plane. "Infinity" indicates that the surface is flat and the radius of curvature is infinite; the thickness represents the central axial distance between the current surface and the next surface; the refractive index (Nd) represents the ability of the material between the current surface and the next surface to deflect light, with a blank space indicating that the current position is air and the refractive index is 1; the Abbe number (Vd) represents the dispersion characteristics of the material between the current surface and the next surface, with a blank space indicating that the current position is air; and half-aperture represents the effective ray diameter of the lens.

[0060] The optical lens provided in this second embodiment achieves the following technical specifications: The focal length f is 7.72mm, the aperture F# is 1.98, the field of view (DFOV) is 74.4°, and the total optical length (TTL) is 38.9mm.

[0061] Furthermore, Figure 6 This is a spherical aberration curve diagram of the optical lens provided in Embodiment 2 of the present invention. In the diagram, the vertical direction represents the normalized aperture, 0 indicates it is on the optical axis, the vertical vertex represents the maximum pupil radius, and the horizontal direction represents the offset relative to the ideal focal point, in millimeters (mm). Different linear curves in the diagram represent different wavelengths of image formation by the optical lens. Figure 6 It can be seen that the pupil radius is 2.0051 mm, and the axial aberrations at different wavelengths (0.436 μm, 0.486 μm, 0.546 μm, 0.587 μm, 0.656 μm and 0.850 μm) are all controlled within the range of (-0.05 mm, +0.05 mm), indicating that the spherical aberration of the optical lens is well controlled at each wavelength.

[0062] Figure 7This is a ray fan diagram of an optical lens provided in Embodiment 2 of the present invention. The ray fan diagram is one of the most commonly used evaluation methods in modern optical design. In the diagram, the horizontal axis represents the beam aperture, and the vertical axis represents the transverse aberration. Ideally, all curves are straight lines coinciding with the horizontal axis, indicating that all rays converge at the same point on the image plane. The interval corresponding to the vertical axis of the curve represents the maximum dispersion range of the beam on the ideal image plane. The ray fan diagram can reflect not only monochromatic aberrations of different wavelengths but also the magnitude of transverse chromatic aberration. Figure 7 It can be seen that the optical lens closely approximates the horizontal axis at each wavelength in each field of view, indicating that the transverse aberration of each wavelength is well corrected. At the same time, there is no obvious dispersion of each wavelength, indicating that the chromatic aberration of the optical lens is also well corrected, thus ensuring that the optical lens can achieve the high-resolution imaging requirements.

[0063] Figure 8 This is a field curvature distortion diagram of the optical lens provided in Embodiment 2 of the present invention. In the coordinate system on the left side of the diagram, the horizontal coordinate represents the magnitude of the field curvature, in millimeters (mm); the vertical coordinate represents the normalized image height, which has no unit; where the solid line represents the meridion and the dashed line represents the arc distortion; Figure 8 It can be seen that the optical lens provided in this embodiment effectively controls the field curvature of light with wavelengths from 436nm to 850nm, meaning that during imaging, the difference in image quality between the center and the periphery is small; in the coordinate system on the right, the horizontal axis represents the magnitude of F-Tan (Theta) distortion, in %; the vertical axis represents the normalized image height, which has no unit; from Figure 8 It can be seen that the optical lens provided in this embodiment has achieved good distortion correction in the wavelength range of 436nm to 850nm.

[0064] Example 3 Figure 9 This is a schematic diagram of the structure of the optical lens provided in Embodiment 3 of the present invention, as shown below. Figure 9 As shown, the optical lens provided in Embodiment 3 of the present invention includes a first lens group 10 and a second lens group 20 arranged sequentially along the optical axis from the object plane to the image plane. The first lens group 10 includes a first lens 101, a second lens 102, a third lens 103, and a fourth lens 104 arranged sequentially along the optical axis from the object plane to the image plane. The second lens group 20 includes a fifth lens 201, a sixth lens 202, a seventh lens 203, an eighth lens 204, and a ninth lens 205 arranged sequentially along the optical axis from the object plane to the image plane. The fifth lens 201 and the sixth lens 202 form a first cemented lens group 31, and the eighth lens 204 and the ninth lens 205 form a second cemented lens group 32. An aperture stop 40 is located in the optical path between the first lens group 10 and the first lens group 20. A filter 50 is located on the image side of the ninth lens 205.

[0065] Table 3 details the specific optical physical parameters of each lens in the optical lens provided in Embodiment 3 of the present invention, according to a feasible implementation method.

[0066] Table 3 Design values ​​of optical physical parameters of optical lenses

[0067] In Table 3, the surface numbers are assigned according to the surface sequence of each lens. For example, surface number "S1" represents the object-side surface of the first lens, surface number "S2" represents the image-side surface of the first lens, and so on. "STO" represents the aperture stop of the optical lens; "OBJ" represents the object plane; "IMA" represents the image plane; the radius of curvature represents the curvature of the lens surface, with a positive value indicating that the surface bends towards the image plane and a negative value indicating that the surface bends towards the object plane. "Infinity" indicates that the surface is flat and the radius of curvature is infinite; the thickness represents the central axial distance between the current surface and the next surface; the refractive index (Nd) represents the ability of the material between the current surface and the next surface to deflect light, with a blank space indicating that the current position is air and the refractive index is 1; the Abbe number (Vd) represents the dispersion characteristics of the material between the current surface and the next surface, with a blank space indicating that the current position is air; and half-aperture represents the effective ray diameter of the lens.

[0068] The optical lens provided in this embodiment three achieves the following technical specifications: The focal length f is 7.91mm, the aperture F# is 1.90, the field of view DFOV is 74.6°, and the total optical length TTL is 38.86mm.

[0069] Furthermore, Figure 10 This is a spherical aberration curve diagram of the optical lens provided in Embodiment 3 of the present invention. In the diagram, the vertical direction represents the normalized aperture, 0 indicates it is on the optical axis, the vertical vertex represents the maximum pupil radius, and the horizontal direction represents the offset relative to the ideal focal point, with units in millimeters (mm). Different linear curves in the diagram represent different wavelengths of image formation by the optical lens. Figure 10 It can be seen that the pupil radius is 1.9892 mm, and the axial aberrations at different wavelengths (0.436 μm, 0.486 μm, 0.546 μm, 0.587 μm, 0.656 μm and 0.850 μm) are all controlled within the range of (-0.1 mm, +0.1 mm), indicating that the spherical aberration of the optical lens is well controlled at each wavelength.

[0070] Figure 11This is a ray fan diagram of an optical lens provided in Embodiment 3 of the present invention. The ray fan diagram is one of the most commonly used evaluation methods in modern optical design. In the diagram, the horizontal axis represents the beam aperture, and the vertical axis represents the transverse aberration. Ideally, all curves are straight lines coinciding with the horizontal axis, indicating that all rays converge at the same point on the image plane. The interval corresponding to the vertical axis of the curve represents the maximum dispersion range of the beam on the ideal image plane. The ray fan diagram can reflect not only monochromatic aberrations of different wavelengths but also the magnitude of transverse chromatic aberration. Figure 11 It can be seen that the optical lens closely approximates the horizontal axis at each wavelength in each field of view, indicating that the transverse aberration of each wavelength is well corrected. At the same time, there is no obvious dispersion of each wavelength, indicating that the chromatic aberration of the optical lens is also well corrected, thus ensuring that the optical lens can achieve the high-resolution imaging requirements.

[0071] Figure 12 This is a field curvature distortion diagram of the optical lens provided in Embodiment 3 of the present invention. In the coordinate system on the left side of the diagram, the horizontal coordinate represents the magnitude of the field curvature, in millimeters (mm); the vertical coordinate represents the normalized image height, which has no unit; where the solid line represents the meridion and the dashed line represents the arc distortion; Figure 12 It can be seen that the optical lens provided in this embodiment effectively controls the field curvature of light with wavelengths from 436nm to 850nm, meaning that during imaging, the difference in image quality between the center and the periphery is small; in the coordinate system on the right, the horizontal axis represents the magnitude of F-Tan (Theta) distortion, in %; the vertical axis represents the normalized image height, which has no unit; from Figure 12 It can be seen that the optical lens provided in this embodiment has achieved good distortion correction in the wavelength range of 436nm to 850nm.

[0072] Example 4 Figure 13 This is a schematic diagram of the structure of the optical lens provided in Embodiment 4 of the present invention, as shown below. Figure 13 As shown, the optical lens provided in Embodiment 4 of the present invention includes a first lens group 10 and a second lens group 20 arranged sequentially along the optical axis from the object plane to the image plane. The first lens group 10 includes a first lens 101, a second lens 102, a third lens 103, and a fourth lens 104 arranged sequentially along the optical axis from the object plane to the image plane. The second lens group 20 includes a fifth lens 201, a sixth lens 202, a seventh lens 203, an eighth lens 204, and a ninth lens 205 arranged sequentially along the optical axis from the object plane to the image plane. The fifth lens 201 and the sixth lens 202 form a first cemented lens group 31, and the eighth lens 204 and the ninth lens 205 form a second cemented lens group 32. An aperture stop 40 is located in the optical path between the first lens group 10 and the first lens group 20. A filter 50 is located on the image side of the ninth lens 205.

[0073] Table 4 details the specific optical physical parameters of each lens in the optical lens provided in Embodiment 4 of the present invention, according to a feasible implementation method.

[0074] Table 4 Design values ​​of optical physical parameters of optical lenses

[0075] In Table 4, the surface numbers are assigned according to the surface sequence of each lens. For example, surface number "S1" represents the object-side surface of the first lens, surface number "S2" represents the image-side surface of the first lens, and so on. "STO" represents the aperture stop of the optical lens; "OBJ" represents the object plane; "IMA" represents the image plane; the radius of curvature represents the curvature of the lens surface, with a positive value indicating that the surface bends towards the image plane and a negative value indicating that the surface bends towards the object plane. "Infinity" indicates that the surface is flat and the radius of curvature is infinite; the thickness represents the central axial distance between the current surface and the next surface; the refractive index (Nd) represents the ability of the material between the current surface and the next surface to deflect light, with a blank space indicating that the current position is air and the refractive index is 1; the Abbe number (Vd) represents the dispersion characteristics of the material between the current surface and the next surface, with a blank space indicating that the current position is air; and half-aperture represents the effective ray diameter of the lens.

[0076] The optical lens provided in this embodiment four achieves the following technical specifications: The focal length f is 7.93mm, the aperture F# is 2.0, the field of view DFOV is 76°, and the total optical length TTL is 39.0mm.

[0077] Furthermore, Figure 14 This is a spherical aberration curve diagram of the optical lens provided in Embodiment 4 of the present invention. In the diagram, the vertical direction represents the normalized aperture, 0 indicates it is on the optical axis, the vertical vertex represents the maximum pupil radius, and the horizontal direction represents the offset relative to the ideal focal point, in millimeters (mm). Different linear curves in the diagram represent different wavelengths of image formation by the optical lens. Figure 14 It can be seen that the pupil radius is 1.9813 mm, and the axial aberrations at different wavelengths (0.436 μm, 0.486 μm, 0.546 μm, 0.587 μm, 0.656 μm and 0.850 μm) are all controlled within the range of (-0.1 mm, +0.1 mm), indicating that the spherical aberration of the optical lens is well controlled at each wavelength.

[0078] Figure 15This is a ray fan diagram of an optical lens provided in Embodiment 4 of the present invention. The ray fan diagram is one of the most commonly used evaluation methods in modern optical design. In the diagram, the horizontal axis represents the beam aperture, and the vertical axis represents the transverse aberration. Ideally, all curves are straight lines coinciding with the horizontal axis, indicating that all rays converge at the same point on the image plane. The interval corresponding to the vertical axis of the curve represents the maximum dispersion range of the beam on the ideal image plane. The ray fan diagram can reflect not only monochromatic aberrations of different wavelengths but also the magnitude of transverse chromatic aberration. Figure 15 It can be seen that the optical lens closely approximates the horizontal axis at each wavelength in each field of view, indicating that the transverse aberration of each wavelength is well corrected. At the same time, there is no obvious dispersion of each wavelength, indicating that the chromatic aberration of the optical lens is also well corrected, thus ensuring that the optical lens can achieve the high-resolution imaging requirements.

[0079] Figure 16 This is a field curvature distortion diagram of the optical lens provided in Embodiment 4 of the present invention. In the coordinate system on the left side of the diagram, the horizontal coordinate represents the magnitude of the field curvature, in millimeters (mm); the vertical coordinate represents the normalized image height, which has no unit; where the solid line represents the meridion and the dashed line represents the arc distortion; Figure 16 It can be seen that the optical lens provided in this embodiment effectively controls the field curvature of light with wavelengths from 436nm to 850nm, meaning that during imaging, the difference in image quality between the center and the periphery is small; in the coordinate system on the right, the horizontal axis represents the magnitude of F-Tan (Theta) distortion, in %; the vertical axis represents the normalized image height, which has no unit; from Figure 16 It can be seen that the optical lens provided in this embodiment has achieved good distortion correction in the wavelength range of 436nm to 850nm.

[0080] To provide a clearer explanation of the above embodiments, Table 5 details the specific optical physical parameters of each lens in the optical lenses provided in embodiments one through four of the present invention.

[0081] Table 5 Design values ​​of optical physical parameters of optical lenses

[0082] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. An optical lens, characterized in that, It includes a first lens group and a second lens group arranged sequentially along the optical axis from the object plane to the image plane; The first lens group includes a first lens, a second lens, a third lens, and a fourth lens arranged sequentially along the optical axis from the object plane to the image plane; The second lens group includes a fifth lens, a sixth lens, a seventh lens, an eighth lens, and a ninth lens arranged sequentially along the optical axis from the object plane to the image plane; The first lens has negative optical power, the second lens has positive optical power, the third lens has negative optical power, the fourth lens has positive optical power, the fifth lens has positive optical power, the sixth lens has negative optical power, the seventh lens has positive optical power, the eighth lens has positive optical power, and the ninth lens has negative optical power. The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, and the ninth lens are all glass spherical lenses; The optical lens contains nine lenses with optical power. The fifth lens and the sixth lens form a first cemented lens group; the eighth lens and the ninth lens form a second cemented lens group; The optical power of the optical lens is Φeff, the optical power of the first lens group is ΦA, and the optical power of the second lens group is ΦB, wherein -5.50 < Φeff / ΦA < 15.50, 0.85 < Φeff / ΦB < 3.25, and -0.95 < ΦA / ΦB < 0.55; The focal length of the optical lens is f, the entrance pupil diameter of the optical lens is D, the total optical length of the optical lens is TTL, and the half-image height of the optical lens is Imah, wherein 1.9≤f / D≤2.0, 4.91≤TTL / f≤5.04, and 0.55≤ImaH / f≤0.

75.

2. The optical lens according to claim 1, characterized in that, The optical lens also includes an aperture stop; The aperture is located in the optical path between the first lens group and the second lens group.

3. The optical lens according to claim 1, characterized in that, 30.0mm≤TTL≤40.0mm.

4. The optical lens according to claim 1, characterized in that, The optical back focal length of the optical lens is OBFL, where 0.15≤OBFL / TTL≤0.35.

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