Day and night confocal optical lens

Abstract

The application discloses a day and night confocal optical lens. The day and night confocal optical lens comprises a first lens with a focal power of Phi1, a second lens with a focal power of Phi2, a third lens with a focal power of Phi3, a fourth lens with a focal power of Phi4, a fifth lens with a focal power of Phi5, a sixth lens with a focal power of Phi6, a seventh lens with a focal power of Phi7, an eighth lens with a focal power of Phi8 and a ninth lens with a focal power of Phi9 arranged in sequence along an optical axis from an object plane to an image plane; wherein -0.62 <= Phi1 / Phi <= -0.41; -0.43 <= (Phi2+Phi3) / Phi <= -0.03; 0.41 <= (Phi4+Phi5+Phi6) / Phi <= 0.63; 0.25 <= (Phi7+Phi8+Phi9) / Phi <= 0.42; and Phi is the optical system focal power of the optical lens. By reasonably distributing the focal power of each lens, the high-quality imaging requirement of weak ambient light can be met.

Description

Technical Field

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

[0002] Because confocal day-night lenses can produce good images in both strong and weak light conditions, they are widely used in security equipment. However, due to the structural limitations of confocal day-night lenses, the image quality of existing confocal day-night lenses in low ambient light conditions cannot be further improved. Summary of the Invention

[0003] This invention provides an optical lens that is confocal day and night to meet the requirements of high imaging quality under weak ambient light.

[0004] The present invention provides an optical lens with day and night confocal focus, comprising: a first lens with an optical power of Φ1, a second lens with an optical power of Φ2, a third lens with an optical power of Φ3, a fourth lens with an optical power of Φ4, a fifth lens with an optical power of Φ5, a sixth lens with an optical power of Φ6, a seventh lens with an optical power of Φ7, an eighth lens with an optical power of Φ8, and a ninth lens with an optical power of Φ9, arranged sequentially along the optical axis from the object plane to the image plane;

[0005] Where -0.62≤Φ1 / Φ≤-0.41;

[0006] -0.43≤(Φ2+Φ3) / Φ≤-0.03;

[0007] 0.41≤(Φ4+Φ5+Φ6) / Φ≤0.63;

[0008] 0.25≤(Φ7+Φ8+Φ9) / Φ≤0.42;

[0009] Φ represents the optical system power of the optical lens.

[0010] Optionally, the first lens, the second lens, the fifth lens, and the eighth lens all have negative optical power;

[0011] The third lens, the fourth lens, the sixth lens, the seventh lens, and the ninth lens all have positive optical power.

[0012] Optionally, the object-side surface of the first lens is convex, and the image-side surface of the first lens is concave.

[0013] Both the object-side and image-side surfaces of the second lens are concave.

[0014] The object-side surface of the third lens is convex, and the image-side surface of the third lens is concave.

[0015] Both the object-side and image-side surfaces of the fourth lens are convex.

[0016] Both the object-side and image-side surfaces of the sixth lens are convex.

[0017] The eighth lens has a concave surface on the object side near the optical axis and a convex surface on the image side near the optical axis.

[0018] The ninth lens has convex surfaces on both the object-side and image-side surfaces in the near-optical axis region.

[0019] Optionally, the refractive index Nd1 and Abbe number Vd1 of the first lens satisfy: 1.54 <Nd1<1.91,25.10<Vd1<65。

[0020] Optionally, the refractive index Nd4 of the fourth lens satisfies: 1.78 <Nd4<2.15。

[0021] Optionally, the refractive index Nd6 and Abbe number Vd6 of the sixth lens satisfy: 1.47 <Nd6<1.68,42<Vd6<98。

[0022] Optionally, the effective diameter D1 of the first lens object side and the total optical system length TTL of the optical lens satisfy the following condition: 0.39≤D1 / TTL≤0.54.

[0023] Optionally, the first lens, the fourth lens, the fifth lens, and the sixth lens are all glass spherical lenses;

[0024] The second lens, the third lens, the seventh lens, the eighth lens, and the ninth lens are all plastic aspherical lenses.

[0025] Optionally, the second lens and the third lens are glued together; or,

[0026] The second lens and the third lens are supported by a spacer or a gasket.

[0027] Optionally, the fifth lens and the sixth lens constitute a cemented doublet lens, and the fourth lens is supported by the cemented doublet lens through a spacer or a gasket; or, the fourth lens, the fifth lens, and the sixth lens constitute a cemented triplicate lens.

[0028] The technical solution of this invention, by sequentially arranging 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 along the optical axis from the object plane to the image plane, and rationally allocating the optical power range of each lens, allows light to transition smoothly when propagating in the optical system of the optical lens, which is beneficial to the correction of system aberrations. As a result, it can have high imaging quality under ambient light of different brightness, that is, meet the high-quality imaging requirements of weak ambient light.

[0029] 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

[0030] 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.

[0031] Figure 1 This is a schematic diagram of the structure of a day-night confocal optical lens provided by the present invention;

[0032] Figure 2 yes Figure 1 A schematic diagram of the spherical aberration curve of a day-night confocal optical lens is shown.

[0033] Figure 3 yes Figure 1 A schematic diagram of the field curvature distortion curve of a day-night confocal optical lens is shown.

[0034] Figure 4 This is a schematic diagram of another day-night confocal optical lens provided in an embodiment of the present invention;

[0035] Figure 5 yes Figure 4 A schematic diagram of the spherical aberration curve of a day-night confocal optical lens is shown.

[0036] Figure 6 yes Figure 4 A schematic diagram of the field curvature distortion curve of a day-night confocal optical lens is shown.

[0037] Figure 7 This is a schematic diagram of the structure of another day-night confocal optical lens provided in an embodiment of the present invention;

[0038] Figure 8 yes Figure 7A schematic diagram of the spherical aberration curve of a day-night confocal optical lens is shown.

[0039] Figure 9 yes Figure 7 A schematic diagram of the field curvature distortion curve of a day-night confocal optical lens is shown.

[0040] Figure 10 This is a schematic diagram of the structure of another day-night confocal optical lens provided in an embodiment of the present invention;

[0041] Figure 11 yes Figure 10 A schematic diagram of the spherical aberration curve of a day-night confocal optical lens is shown.

[0042] Figure 12 yes Figure 10 The diagram shows the field curvature distortion curve of a day-night confocal optical lens. Detailed Implementation

[0043] 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.

[0044] 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 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 non-exclusive inclusion; for example, a system, product, or device comprising a series of units is not necessarily limited to those steps or units explicitly listed, but may include other units not explicitly listed or inherent to such products or devices.

[0045] Figure 1 This is a schematic diagram of the structure of an optical lens with day and night confocal focus provided by an embodiment of the present invention, as shown below. Figure 1As shown, the day-night confocal optical lens provided in this embodiment of the invention includes a first lens 10 with an optical power of Φ1, a second lens 20 with an optical power of Φ2, a third lens 30 with an optical power of Φ3, a fourth lens 40 with an optical power of Φ4, a fifth lens 50 with an optical power of Φ5, a sixth lens 60 with an optical power of Φ6, a seventh lens 70 with an optical power of Φ7, an eighth lens 80 with an optical power of Φ8, and a ninth lens 90 with an optical power of Φ9, arranged sequentially along the optical axis from the object plane to the image plane; wherein, -0.62≤Φ1 / Φ≤-0.41; -0.43≤(Φ2+Φ3) / Φ≤-0.03; 0.41≤(Φ4+Φ5+Φ6) / Φ≤0.63; 0.25≤(Φ7+Φ8+Φ9) / Φ≤0.42; Φ is the optical power of the optical system of the optical lens.

[0046] 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 of multiple lenses (i.e., a lens group).

[0047] Specifically, each of the lenses from the first lens 10 to the ninth lens 90 can be fixed in a single lens barrel. Figure 1In the section (not shown), by setting the ratio of the optical power Φ1 of the first lens 10 to the optical power Φ of the entire optical system to a negative value, with a value between -0.62 and -0.41, a larger field of view can be achieved, and the object-side light can enter the subsequent optical system smoothly, reducing the proportion of higher-order aberrations. Setting the ratio of the sum of the optical powers Φ3+Φ2 of the second lens 20 and the third lens 30 to the optical power Φ of the entire optical system to a negative value, with a value between -0.43 and -0.03, effectively reduces the angle of deviation of the light passing through the first lens 10 and then through the second and third lenses 20, which is beneficial for correcting system aberrations. Setting the ratio of the sum of the optical powers Φ4+Φ5+Φ6 of the fourth lens 40, the fifth lens 50, and the sixth lens 60 to the optical power Φ of the entire optical system to a positive value, with a value between 0.4 and -0.4, results in a larger field of view and allows the object-side light to enter the subsequent optical system more smoothly, reducing the proportion of higher-order aberrations. A value between 1 and 0.63 allows light rays passing through the first lens 10, second lens 20, and third lens 30 to gradually transition into the subsequent parts of the system after passing through the fourth lens 40, fifth lens 50, and sixth lens 60. This further corrects system aberrations, reduces assembly tolerances between lenses, simplifies the assembly of the entire optical system, and improves its assemblability. Setting the sum of the optical powers of the seventh lens 70, eighth lens 80, and ninth lens 90, Φ7+Φ8+Φ9, to a positive value between 0.25 and 0.42 ensures that the optical powers of the lens combinations with positive and negative powers are proportionally equal in the overall optical power of the system. This ensures that light rays reach the image plane smoothly while further correcting system aberrations, resulting in high image quality under ambient light of varying brightness.

[0048] This invention, through the sequential arrangement of 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 along the optical axis from the object plane to the image plane, and the reasonable allocation of the optical power range of each lens, allows light to propagate smoothly through the optical system of the optical lens, which is beneficial for the correction of system aberrations. This results in high imaging quality under ambient light of varying brightness, thus meeting the requirements for high-quality imaging in weak ambient light.

[0049] Optionally, the first lens 10, the second lens 20, the fifth lens 50 and the eighth lens 80 all have negative optical power; the third lens 30, the fourth lens 40, the sixth lens 60, the seventh lens 70 and the ninth lens 90 all have positive optical power.

[0050] Specifically, by making the first lens 10 have a negative optical power, the optical system can have a large field of view; and by setting the second lens 20 to also have a negative optical power, the light passing through the first lens 10 can smoothly enter the second lens 20; by setting the third lens 30 and the fourth lens 40 to have positive optical power, the light passing through the second lens 20 can have its deflection angle effectively reduced after passing through the third lens 30 and the fourth lens 40; at the same time, by setting the fifth lens 50 and the eighth lens 80 to have negative optical power, and the sixth lens 60, the seventh lens 70 and the ninth lens 90 to have positive optical power, the light can smoothly transition between the lenses in the optical system, which is beneficial for the correction of system aberrations and meets the requirement of large light transmission, thereby enabling high imaging quality under both strong and weak ambient light.

[0051] Optionally, the object-side surface of the first lens 10 is convex, and the image-side surface of the first lens 10 is concave; both the object-side surface and the image-side surface of the second lens 20 are concave; the object-side surface of the third lens 30 is convex, and the image-side surface of the third lens 30 is concave; both the object-side surface and the image-side surface of the fourth lens 40 are convex; both the object-side surface and the image-side surface of the sixth lens 60 are convex; the object-side surface of the eighth lens 80 in the near-optical axis region is concave, and the image-side surface of the eighth lens 80 in the near-optical axis region is convex; and both the object-side surface and the image-side surface of the ninth lens 90 in the near-optical axis region are convex.

[0052] In this design, by setting the object-side surface of the first lens 10 to be convex and the image-side surface to be concave, the first lens 10 is a meniscus lens. This ensures that the optical system has a large field of view while allowing light to enter the subsequent optical system at a small angle of incidence. Simultaneously, by setting the second lens 20 as a biconcave lens, the third lens 30 as a convex-concave lens, the fourth lens 40 and the sixth lens 60 as biconvex lenses, the eighth lens 80 as a concave-convex lens, and the ninth lens 90 as a biconvex lens, the shapes of the lenses are complementary. This simplifies the assembly of the lenses while correcting system aberrations, and facilitates the formation of a compact optical system. This reduces the size of the optical system, allowing it to have a larger imaging target surface and be compatible with 1 / 2.7-inch chips. In an exemplary embodiment, the effective diameter of the imaging target surface of this optical system can be greater than or equal to 7 mm.

[0053] Optionally, the effective diameter D1 of the object side of the first lens 10 and the total optical system length TTL of the optical lens satisfy the following condition: 0.39≤D1 / TTL≤0.54.

[0054] Herein, the larger the effective diameter D1 of the first lens 10 is, the larger the field of view of the optical system including the first lens 10 will be. However, when the effective diameter D1 of the first lens 10 increases, the size of the entire optical system will be increased. In this case, by setting the ratio between the effective diameter D1 of the first lens 10 and the total track length TTL of the optical system to a value within the range of 0.39 to 0.54, it is possible to make the structure of the optical system more compact, reduce the size of the optical system, and lower the manufacturing cost of the optical system while ensuring that the optical system has a large field of view, so as to be compatible with a 1 / 2.7-inch chip. In an exemplary embodiment, the total track length of the optical system may be less than or equal to 22.5 mm.

[0055] Optionally, the first lens 10, the fourth lens 40, the fifth lens 50 and the sixth lens 60 are all glass spherical lenses; the second lens 20, the third lens 30, the seventh lens 70, the eighth lens 80 and the ninth lens 90 are all plastic aspheric lenses. In this way, under the premise of reasonably distributing the optical power of each lens, by adopting a glass-plastic hybrid structure for each lens in the optical system, the F-number can be close to 1, and the optical system has an infrared confocal function, so that the aberrations of the optical lens in the wavelength range of 436 nm to 850 nm can be reasonably corrected and balanced, and high-quality imaging requirements can still be met in an environment of -40°C to 80°C.

[0056] Optionally, the refractive index Nd1 and the Abbe number Vd1 of the first lens 10 satisfy: 1.54<Nd1<1.91, 25.10<Vd1<65.

[0057] Herein, the refractive index is the ratio of the propagation speed of light in a vacuum to the propagation speed of light in the medium, which is mainly used to describe the refraction ability of a material to light, and different materials have different refractive indices. The Abbe number is an index used to represent the dispersion ability of a transparent medium. The more severe the dispersion of the medium, the smaller the Abbe number; conversely, the milder the dispersion of the medium, the larger the Abbe number. In this way, by reasonably setting the refractive index and Abbe number of the first lens, it can be ensured that the optical system has an ultra-large field of view.

[0058] Optionally, the refractive index Nd4 of the fourth lens 40 satisfies: 1.78<Nd4<2.15. In this way, the fourth lens 40 has a relatively large refractive index, and the optical power of the fourth lens 40 is positive, so that light rays can be effectively converged, thereby effectively reducing the deflection angle of the system, enabling the light rays to enter the subsequent optical system gently, and at the same time facilitating the reduction of assembly tolerances of the optical system.

[0059] Optionally, the refractive index Nd6 and the Abbe number Vd6 of the sixth lens 60 satisfy: 1.47<Nd6<1.68, 42<Vd6<98. In this way, by reasonably setting the refractive index and Abbe number of the sixth lens 60, the material of the sixth lens 60 can effectively reduce the imaging chromatic aberration of the optical system, and meet the requirement of day and night confocal.

[0060] Optionally, the second lens 20 and the third lens 30 can be abutted against each other via a spacer or a shim, or the second lens 20 and the third lens 30 can also be bonded by glue, so that the second lens 20 and the third lens 30 form a cemented lens.

[0061] Optionally, the fourth lens 40 and the fifth lens 50 can be abutted against each other via a spacer or a shim, and the fifth lens 50 and the sixth lens 60 can also be abutted against each other via a spacer or a shim; or, the fifth lens 50 and the sixth lens 60 form a double cemented lens, that is, the fifth lens 50 and the sixth lens 60 are bonded by glue, and the fourth lens 40 and the double cemented lens formed by the fifth lens 50 and the sixth lens 60 are abutted against each other via a spacer or a shim; or, the fourth lens 40, the fifth lens 50 and the sixth lens 60 can also form a triple cemented lens.

[0062] In this way, by making the lenses abut against each other or be bonded by glue, the air gap between the lenses can be effectively reduced, thereby reducing the total length of the optical system of the lens. In addition, when adjacent lenses form a cemented lens, chromatic aberration can be minimized or eliminated, so that various aberrations of the day and night confocal optical lens can be fully corrected. On the premise of a compact structure, the resolution can be improved and the optical performance can be optimized; at the same time, when adjacent lenses form a cemented lens, the light loss caused by light reflection between the lenses can also be reduced, the illuminance is improved, thereby improving the image quality and enhancing the clarity of imaging; in addition, the use of a cemented lens can also reduce the assembly components between two adjacent lenses, simplify the assembly procedure in the manufacturing process of the optical lens, reduce the cost, and reduce the tolerance sensitivity problems such as tilt / decentration of a single lens generated during the assembly process.

[0063] Optionally, the day and night confocal optical lens may further include an optical filter 100, which is disposed on the image side of the ninth lens 90. The optical filter 100 can filter out unwanted stray light, so as to improve the image quality of the day and night confocal optical lens, for example, the optical filter 100 filters out infrared light during the day to improve the imaging quality of the day and night confocal optical lens. At the same time, the optical filter 100 can also protect the imaging sensor.

[0064] By rationally allocating the optical power of each lens, the day-night confocal optical lens can achieve reasonable correction and balance of aberrations in the wavelength range of 436-850nm, thus enabling the day-night confocal optical lens to meet the requirements of excellent imaging, compact structure, large light transmission, day-night confocality, and wide angle.

[0065] The following describes in further detail, with reference to the accompanying drawings, specific embodiments of the day-night confocal optical lens applicable to the above-described embodiments.

[0066] In one feasible embodiment, Table 1 details a feasible implementation method. Figure 1 The specific optical and physical parameters of the fixed-focus lens are shown.

[0067] Table 1. Design of optical physical parameters for a day / night confocal lens.

[0068] Range of values Example 1 lower limit upper limit Φ1 / Φ -0.52 -0.62 -0.41 (Φ2+Φ3) / Φ -0.23 -0.43 -0.03 (Φ4+Φ5+Φ6) / Φ 0.48 0.41 0.63 (Φ7+Φ8+Φ9) / Φ 0.30 0.25 0.42 D1 / TTL 0.43 0.39 0.54 Nd1 1.83 1.54 1.91 Nd4 2.05 1.78 2.15 Nd6 1.59 1.47 1.68 Vd1 45.50 25.10 65.00 Vd6 80.00 42.00 98.00

[0069] The day-night confocal optical lens of this embodiment has a focal length f of 3.099mm, an aperture number F of 1.08, and a field of view of 143.54° when the size of the imaging target surface φ is 7mm.

[0070] Table 2 shows the design parameters of each lens in a day-night confocal optical lens, including surface type, radius of curvature, thickness, and material, corresponding to Table 1.

[0071] Table 2. Parameter design of each lens in a day / night confocal optical lens.

[0072]

[0073] The day / night confocal optical lens provided in this embodiment includes a first lens 10, a second lens 20, a third lens 30, a fourth lens 40, a fifth lens 50, a sixth lens 60, an aperture stop (not shown in the figure), a seventh lens 70, an eighth lens 80, a ninth lens 90, and a filter 100 arranged sequentially along the optical axis from the object side to the image side. The surface numbers in Table 2 are numbered according to the surface order of each lens. "OBJ" represents the object plane of the lens; "STO" represents the aperture stop of the lens; "IMA" represents the image plane of the lens; "S1" represents the object-side surface of the first lens 10, "S2" represents the image-side surface of the first lens 10, "S3" represents the object-side surface of the second lens 20, and so on. "S17" represents the object-side surface of the filter 100, and "S18" represents the image-side surface of the filter 100. The radius of curvature represents the curvature of the lens surface; a positive value indicates that the surface bends towards the image plane, and a negative value indicates that the surface bends towards the object plane. "Infinity" indicates that the surface is flat, with an infinite radius of curvature and an infinite distance. The thickness represents the central axial distance between the current surface and the next surface. The refractive index represents the ability of the material between the current surface and the next surface to deflect light; a space indicates that the current location is air, and the refractive index is 1. The Abbe number represents the dispersion characteristics of the material between the current surface and the next surface; a space indicates that the current location is air. Half-aperture represents the light-gathering capability of the lens at its maximum aperture. The k-value represents the magnitude of the conic coefficient of the aspherical surface.

[0074] The aspherical conic coefficient of the day-night confocal optical lens in this embodiment can be defined by the following aspherical formula, but is not limited to the following representation:

[0075]

[0076] Where z is the axial sagitta in the Z direction of the aspherical surface; r is the height of the aspherical surface; c is the curvature of the fitted sphere, which is numerically the reciprocal of the radius of curvature; k is the coefficient of the fitted cone; A, B, C, D, E and F are the coefficients of the 4th, 6th, 8th, 10th, 12th and 14th order terms of the aspherical polynomial, respectively.

[0077] Table 3 Aspherical coefficients of a day-night confocal optical lens

[0078]

[0079] Where 3.00146E-03 indicates that the coefficient A of surface number S3 is 3.00146 × 10 -3 .

[0080] Figure 2 yes Figure 1 The diagram shows the spherical aberration curve of an optical lens with confocal day and night orientation. Figure 3 yes Figure 1 The diagram shows the field curvature distortion curve of a day / night confocal optical lens. (See attached diagram.) Figure 2 The axial aberration curves shown have the following relationships: the vertical direction represents the normalized aperture, 0 indicates it is on the optical axis, and the vertical vertex represents the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focus, in millimeters (mm); the different linear curves in the figure represent the different wavelengths imaged by the optical system of the day-night confocal lens; from... Figure 2 It can be seen that the axial aberrations at different wavelengths are all controlled within the range of (-0.05mm, +0.05mm). This indicates that the day-night confocal optical lens achieves good control of spherical aberration at various wavelengths, meeting the requirements for wide-spectrum applications. Figure 3 The field curvature distortion curve shown in the figure has the following coordinate system on the left: the horizontal axis represents the magnitude of the field curvature in mm; the vertical axis represents the normalized image height (unitless); where T represents the meridion and S represents the sagitta; from Figure 3 As can be seen, the day-night confocal optical lens provided in this embodiment can effectively control the field curvature of light with wavelengths from 436nm to 850nm. That is, during imaging, the difference between the image quality at the center and the image quality at the periphery is small. In the coordinate system on the right, the horizontal coordinate represents the magnitude of distortion in %; the vertical coordinate represents the normalized image height, which has no unit.

[0081] In another feasible embodiment, Figure 4 This is a schematic diagram of another day-night confocal optical lens provided in an embodiment of the present invention. Table 4 details a feasible implementation method. Figure 4 The specific optical physical parameters of the day-night confocal lens are shown.

[0082] Table 4. Another optical physical parameter design for day and night confocal optical lenses.

[0083] Range of values Example 2 lower limit upper limit Φ1 / Φ -0.47 -0.62 -0.41 (Φ2+Φ3) / Φ -0.40 -0.43 -0.03 (Φ4+Φ5+Φ6) / Φ 0.60 0.41 0.63 (Φ7+Φ8+Φ9) / Φ 0.32 0.25 0.42 D1 / TTL 0.48 0.39 0.54 Nd1 1.59 1.54 1.91 Nd4 2.10 1.78 2.15 Nd6 1.50 1.47 1.68 Vd1 45.08 25.10 65.00 Vd6 90.00 42.00 98.00

[0084] The day-night confocal optical lens of this embodiment has a focal length f of 3.071mm, an aperture number F of 1.08, and a field of view of 145.15° when the size of the imaging target surface φ is 7mm.

[0085] Table 5 shows the design parameters of each lens in a day-night confocal optical lens, including surface type, radius of curvature, thickness, and material, corresponding to Table 4.

[0086] Table 5. Another parameter design for each lens in a day-night confocal optical lens.

[0087]

[0088] The day / night confocal optical lens provided in this embodiment includes a first lens 10, a second lens 20, a third lens 30, a fourth lens 40, a fifth lens 50, a sixth lens 60, an aperture stop (not shown in the figure), a seventh lens 70, an eighth lens 80, a ninth lens 90, and a filter 100 arranged sequentially along the optical axis from the object side to the image side. The surface numbers in Table 2 are numbered according to the surface order of each lens. "OBJ" represents the object plane of the lens; "STO" represents the aperture stop of the lens; "IMA" represents the image plane of the lens; "S1" represents the object-side surface of the first lens 10, "S2" represents the image-side surface of the first lens 10, "S3" represents the object-side surface of the second lens 20, and so on. "S16" represents the object-side surface of the filter 100, and "S17" represents the image-side surface of the filter 100. The radius of curvature represents the curvature of the lens surface; a positive value indicates that the surface bends towards the image plane, and a negative value indicates that the surface bends towards the object plane. "Infinity" indicates that the surface is flat, with an infinite radius of curvature and an infinite distance. The thickness represents the central axial distance between the current surface and the next surface. The refractive index represents the ability of the material between the current surface and the next surface to deflect light; a space indicates that the current location is air, and the refractive index is 1. The Abbe number represents the dispersion characteristics of the material between the current surface and the next surface; a space indicates that the current location is air. Half-aperture represents the light-gathering capability of the lens at its maximum aperture. The k-value represents the magnitude of the conic coefficient of the aspherical surface.

[0089] The aspherical conic coefficient of the day-night confocal optical lens in this embodiment can be defined by the following aspherical formula, but is not limited to the following representation:

[0090]

[0091] Where z is the axial sagitta in the Z direction of the aspherical surface; r is the height of the aspherical surface; c is the curvature of the fitted sphere, which is numerically the reciprocal of the radius of curvature; k is the coefficient of the fitted cone; A, B, C, D, E and F are the coefficients of the 4th, 6th, 8th, 10th, 12th and 14th order terms of the aspherical polynomial, respectively.

[0092] Table 6. Aspherical coefficients of another type of day-night confocal optical lens

[0093]

[0094] Where -5.54557E-03 indicates that the coefficient A of surface number S3 is -5.54557 × 10 -3 .

[0095] Figure 5 yes Figure 4 The diagram shows the spherical aberration curve of an optical lens with confocal day and night orientation. Figure 6yes Figure 4 The diagram shows the field curvature distortion curve of a day / night confocal optical lens. (See attached diagram.) Figure 5 The axial aberration curves shown have the following relationships: the vertical direction represents the normalized aperture, 0 indicates it is on the optical axis, and the vertical vertex represents the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focus, in millimeters (mm); the different linear curves in the figure represent the different wavelengths imaged by the optical system of the day-night confocal lens; from... Figure 5 It can be seen that the axial aberrations at different wavelengths are all controlled within the range of (-0.05mm, +0.05mm). This indicates that the day-night confocal optical lens achieves good control of spherical aberration at various wavelengths, meeting the requirements for wide-spectrum applications. Figure 6 The field curvature distortion curve shown in the figure has the following coordinate system on the left: the horizontal axis represents the magnitude of the field curvature in mm; the vertical axis represents the normalized image height (unitless); where T represents the meridion and S represents the sagitta; from Figure 6 As can be seen, the day-night confocal optical lens provided in this embodiment can effectively control the field curvature of light with wavelengths from 436nm to 850nm. That is, during imaging, the difference between the image quality at the center and the image quality at the periphery is small. In the coordinate system on the right, the horizontal coordinate represents the magnitude of distortion in %; the vertical coordinate represents the normalized image height, which has no unit.

[0096] In yet another feasible embodiment, Figure 7 This is a schematic diagram of another day-night confocal optical lens provided in an embodiment of the present invention. Table 7 details a feasible implementation method. Figure 7 The specific optical physical parameters of the day-night confocal lens are shown.

[0097] Table 7. Another optical physical parameter design for a day-night confocal lens.

[0098]

[0099] The day-night confocal optical lens of this embodiment has a focal length f of 2.997mm, an aperture number F of 1.08, and a field of view of 143.50° when the size of the imaging target surface φ is 7mm.

[0100] Table 8 shows the design parameters of each lens in a day-night confocal optical lens, including surface type, radius of curvature, thickness, and material, corresponding to Table 7.

[0101] Table 8 shows another parameter design for each lens in a day-night confocal optical lens.

[0102]

[0103] The day / night confocal optical lens provided in this embodiment includes a first lens 10, a second lens 20, a third lens 30, a fourth lens 40, a fifth lens 50, a sixth lens 60, an aperture stop (not shown in the figure), a seventh lens 70, an eighth lens 80, a ninth lens 90, and a filter 100 arranged sequentially along the optical axis from the object side to the image side. The surface numbers in Table 2 are numbered according to the surface order of each lens. "OBJ" represents the object plane of the lens; "STO" represents the aperture stop of the lens; "IMA" represents the image plane of the lens; "S1" represents the object-side surface of the first lens 10, "S2" represents the image-side surface of the first lens 10, "S3" represents the object-side surface of the second lens 20, and so on. "S18" represents the object-side surface of the filter 100, and "S19" represents the image-side surface of the filter 100. The radius of curvature represents the curvature of the lens surface; a positive value indicates that the surface bends towards the image plane, and a negative value indicates that the surface bends towards the object plane. "Infinity" indicates that the surface is flat, with an infinite radius of curvature and an infinite distance. The thickness represents the central axial distance between the current surface and the next surface. The refractive index represents the ability of the material between the current surface and the next surface to deflect light; a space indicates that the current location is air, and the refractive index is 1. The Abbe number represents the dispersion characteristics of the material between the current surface and the next surface; a space indicates that the current location is air. Half-aperture represents the light-gathering capability of the lens at its maximum aperture. The k-value represents the magnitude of the conic coefficient of the aspherical surface.

[0104] The aspherical conic coefficient of the day-night confocal optical lens in this embodiment can be defined by the following aspherical formula, but is not limited to the following representation:

[0105]

[0106] Where z is the axial sagitta in the Z direction of the aspherical surface; r is the height of the aspherical surface; c is the curvature of the fitted sphere, which is numerically the reciprocal of the radius of curvature; k is the coefficient of the fitted cone; A, B, C, D, E and F are the coefficients of the 4th, 6th, 8th, 10th, 12th and 14th order terms of the aspherical polynomial, respectively.

[0107] Table 9 shows the aspherical coefficients of another type of day-night confocal optical lens.

[0108]

[0109] Where 4.21664E-03 indicates that the coefficient A of surface number S3 is 4.21664 × 10 -3 .

[0110] Figure 8 yes Figure 7 The diagram shows the spherical aberration curve of an optical lens with confocal day and night orientation. Figure 9 yes Figure 7 The diagram shows the field curvature distortion curve of a day / night confocal optical lens. (See attached diagram.) Figure 8 The axial aberration curves shown have the following relationships: the vertical direction represents the normalized aperture, 0 indicates it is on the optical axis, and the vertical vertex represents the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focus, in millimeters (mm); the different linear curves in the figure represent the different wavelengths imaged by the optical system of the day-night confocal lens; from... Figure 8 It can be seen that the axial aberrations at different wavelengths are all controlled within the range of (-0.05mm, +0.05mm). This indicates that the day-night confocal optical lens achieves good control of spherical aberration at various wavelengths, meeting the requirements for wide-spectrum applications. Figure 9 The field curvature distortion curve shown in the figure has the following coordinate system on the left: the horizontal axis represents the magnitude of the field curvature in mm; the vertical axis represents the normalized image height (unitless); where T represents the meridion and S represents the sagitta; from Figure 9 As can be seen, the day-night confocal optical lens provided in this embodiment can effectively control the field curvature of light with wavelengths from 436nm to 850nm. That is, during imaging, the difference between the image quality at the center and the image quality at the periphery is small. In the coordinate system on the right, the horizontal coordinate represents the magnitude of distortion in %; the vertical coordinate represents the normalized image height, which has no unit.

[0111] In yet another feasible embodiment, Figure 10 This is a schematic diagram of another day-night confocal optical lens provided in an embodiment of the present invention. Table 10 details a feasible implementation method. Figure 10 The specific optical physical parameters of the day-night confocal lens are shown.

[0112] Table 10 shows another optical physical parameter design for a day-night confocal lens.

[0113] Range of values Example 4 lower limit upper limit Φ1 / Φ -0.45 -0.62 -0.41 (Φ2+Φ3) / Φ -0.37 -0.43 -0.03 (Φ4+Φ5+Φ6) / Φ 0.58 0.41 0.63 (Φ7+Φ8+Φ9) / Φ 0.39 0.25 0.42 D1 / TTL 0.52 0.39 0.54 Nd1 1.59 1.54 1.91 Nd4 2.10 1.78 2.15 Nd6 1.58 1.47 1.68 Vd1 30.75 25.10 65.00 Vd6 87.54 42.00 98.00

[0114] The day-night confocal optical lens of this embodiment has a focal length f of 3.238mm, an aperture number F of 1.08, and a field of view of 142.51° when the size of the imaging target surface φ is 7mm.

[0115] Table 11 shows the design parameters of each lens in a day-night confocal optical lens, including surface type, radius of curvature, thickness, and material, corresponding to Table 10.

[0116] Table 11 shows another parameter design for each lens in a day-night confocal optical lens.

[0117]

[0118] The day / night confocal optical lens provided in this embodiment includes a first lens 10, a second lens 20, a third lens 30, a fourth lens 40, a fifth lens 50, a sixth lens 60, an aperture stop (not shown in the figure), a seventh lens 70, an eighth lens 80, a ninth lens 90, and a filter 100 arranged sequentially along the optical axis from the object side to the image side. The surface numbers in Table 2 are numbered according to the surface order of each lens. "OBJ" represents the object plane of the lens; "STO" represents the aperture stop of the lens; "IMA" represents the image plane of the lens; "S1" represents the object-side surface of the first lens 10, "S2" represents the image-side surface of the first lens 10, "S3" represents the object-side surface of the second lens 20, and so on. "S16" represents the object-side surface of the filter 100, and "S17" represents the image-side surface of the filter 100. The radius of curvature represents the curvature of the lens surface; a positive value indicates that the surface bends towards the image plane, and a negative value indicates that the surface bends towards the object plane. "Infinity" indicates that the surface is flat, with an infinite radius of curvature and an infinite distance. The thickness represents the central axial distance between the current surface and the next surface. The refractive index represents the ability of the material between the current surface and the next surface to deflect light; a space indicates that the current location is air, and the refractive index is 1. The Abbe number represents the dispersion characteristics of the material between the current surface and the next surface; a space indicates that the current location is air. Half-aperture represents the light-gathering capability of the lens at its maximum aperture. The k-value represents the magnitude of the conic coefficient of the aspherical surface.

[0119] The aspherical conic coefficient of the day-night confocal optical lens in this embodiment can be defined by the following aspherical formula, but is not limited to the following representation:

[0120]

[0121] Where z is the axial sagitta in the Z direction of the aspherical surface; r is the height of the aspherical surface; c is the curvature of the fitted sphere, which is numerically the reciprocal of the radius of curvature; k is the coefficient of the fitted cone; A, B, C, D, E and F are the coefficients of the 4th, 6th, 8th, 10th, 12th and 14th order terms of the aspherical polynomial, respectively.

[0122] Table 12 shows the aspherical coefficients of another type of day-night confocal optical lens.

[0123]

[0124] Where -5.81430E-03 indicates that the coefficient A of surface number S3 is -5.81430 × 10 -3 .

[0125] Figure 11 yes Figure 10 The diagram shows the spherical aberration curve of an optical lens with confocal day and night orientation. Figure 12yes Figure 10 The diagram shows the field curvature distortion curve of a day / night confocal optical lens. (See attached diagram.) Figure 11 The axial aberration curves shown have the following relationships: the vertical direction represents the normalized aperture, 0 indicates it is on the optical axis, and the vertical vertex represents the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focus, in millimeters (mm); the different linear curves in the figure represent the different wavelengths imaged by the optical system of the day-night confocal lens; from... Figure 11 It can be seen that the axial aberrations at different wavelengths are all controlled within the range of (-0.05mm, +0.05mm). This indicates that the day-night confocal optical lens achieves good control of spherical aberration at various wavelengths, meeting the requirements for wide-spectrum applications. Figure 12 The field curvature distortion curve shown in the figure has the following coordinate system on the left: the horizontal axis represents the magnitude of the field curvature in mm; the vertical axis represents the normalized image height (unitless); where T represents the meridion and S represents the sagitta; from Figure 12 As can be seen, the day-night confocal optical lens provided in this embodiment can effectively control the field curvature of light with wavelengths from 436nm to 850nm. That is, during imaging, the difference between the image quality at the center and the image quality at the periphery is small. In the coordinate system on the right, the horizontal coordinate represents the magnitude of distortion in %; the vertical coordinate represents the normalized image height, which has no unit.

[0126] It should be understood that the various structures shown above can be used to rearrange, add, or delete modules, units, etc. For example, the structures described in this invention can exist in parallel or some or all of them, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0127] 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 with day and night confocal focusing, characterized in that, include: The optical lens, arranged sequentially along the optical axis from the object plane to the image plane, comprises a first lens with an optical power of Φ1, a second lens with an optical power of Φ2, a third lens with an optical power of Φ3, a fourth lens with an optical power of Φ4, a fifth lens with an optical power of Φ5, a sixth lens with an optical power of Φ6, a seventh lens with an optical power of Φ7, an eighth lens with an optical power of Φ8, and a ninth lens with an optical power of Φ9; the day-night confocal optical lens contains nine lenses with optical power. Where -0.62≤Φ1 / Φ≤-0.41; -0.43≤(Φ2+Φ3) / Φ≤-0.03; 0.41≤(Φ4+Φ5+Φ6) / Φ≤0.63; 0.25≤(Φ7+Φ8+Φ9) / Φ≤0.42; Φ represents the optical power of the optical system of the day-night confocal lens; The first lens, the fourth lens, the fifth lens, and the sixth lens are all glass spherical lenses; the second lens, the third lens, the seventh lens, the eighth lens, and the ninth lens are all plastic aspherical lenses; the aperture number F of the day-night confocal optical lens is close to 1; The second lens and the third lens are glued together, or the second lens and the third lens are supported by a spacer or a gasket; the fifth lens and the sixth lens form a cemented doublet lens and the fourth lens is supported by a spacer or a gasket, or the fourth lens, the fifth lens and the sixth lens form a cemented triplet lens; The first lens has a convex object-side surface and a concave image-side surface; the second lens has both a concave object-side surface and a concave image-side surface; the third lens has a convex object-side surface and a concave image-side surface; the fourth lens has both a convex object-side surface and a convex image-side surface; the sixth lens has both a convex object-side surface and a convex image-side surface; the eighth lens has a concave object-side surface in the near-optical axis region and a convex image-side surface in the near-optical axis region; the ninth lens has both a convex object-side surface and a convex image-side surface in the near-optical axis region. The first lens, the second lens, the fifth lens, and the eighth lens all have negative optical power; the third lens, the fourth lens, the sixth lens, the seventh lens, and the ninth lens all have positive optical power. The refractive index Nd4 of the fourth lens satisfies: 1.78 <Nd4<2.15。 2. The day-night confocal optical lens according to claim 1, characterized in that, The refractive index Nd1 and Abbe number Vd1 of the first lens satisfy: 1.54 <Nd1<1.91,25.10<Vd1<65。 3. The day-night confocal optical lens according to claim 1, characterized in that, The refractive index Nd6 and Abbe number Vd6 of the sixth lens satisfy: 1.47 <Nd6<1.68,42<Vd6<98。 4. The day-night confocal optical lens according to claim 1, characterized in that, The effective diameter D1 of the object side of the first lens and the total optical system length TTL of the optical lens satisfy the following condition: 0.39≤D1 / TTL≤0.54.

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