Optical lens

Abstract

The invention provides an optical lens, which comprises five lenses from an object side to an imaging surface along an optical axis: a first lens with positive focal power, a second lens with negative focal power, a third lens with positive focal power, a fourth lens with negative focal power and a fifth lens with positive focal power, the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a concave surface; the object side surface of the third lens is a convex surface, and the image side surface of the third lens is a convex surface; the object side surface of the fourth lens is a concave surface, and the image side surface of the fourth lens is a convex surface; the fifth lens has negative focal power, and the image side surface of the fifth lens is a concave surface near the optical axis; wherein the effective focal length f of the optical lens and the focal length f1 of the first lens meet the following conditions: 1.1 lt; f1 / flt; and 1.4. According to the optical lens provided by the invention, through specific surface shape matching and reasonable focal power distribution, the imaging quality of the optical lens is improved, and the lens has one or more advantages of large aperture, miniaturization, low cost and the like while realizing a good day and night confocal effect.

Description

Technical Field

[0001] The present invention relates to the technical field of imaging lenses, and particularly to an optical lens. Background Art

[0002] Due to differences in application environments, consumers have different performance requirements for lenses, but the overall requirements are getting higher and higher. In some application scenarios with complex environments, it is not only required that the lens can be free of defocus under conditions of large temperature differences between high and low temperatures, but also required that the shooting requirements can be met both during the day and at night. For this reason, today's lenses are constantly developing in the direction of lower cost, high-definition image quality, small size, and day-night confocal, and accordingly, a new architecture of day-night confocal lenses has become an object to be developed. Summary of the Invention

[0003] Aiming at the above problems, the purpose of the present invention is to provide an optical lens, which has the advantages of day-night confocal and excellent imaging quality.

[0004] The present invention provides an optical lens, which has a total of five lenses, and successively includes from the object side to the imaging surface along the optical axis: A first lens with positive optical power, whose image side is convex; A second lens with negative optical power, whose object side is convex and whose image side is concave; A third lens with positive optical power, whose object side is convex and whose image side is convex; A fourth lens with negative optical power, whose object side is concave and whose image side is convex; A fifth lens with negative optical power, whose image side is concave near the optical axis; Wherein, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: 1.1 < f1 / f < 1.4.

[0005] Further preferably, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: -6.8 < f5 / f < -0.75.

[0006] Further preferably, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 0.5 < f3 / f < 0.81.

[0007] Further preferably, the optical total length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 1.45 < TTL / f < 1.5.

[0008] Further preferably, the effective focal length f of the optical lens, the maximum field of view FOV of the optical lens, and the true image height IH corresponding to the maximum field of view of the optical lens satisfy: 49° < (f × FOV) / IH < 50°.

[0009] More preferably, the radius of curvature R5 of the object side surface of the third lens and the radius of curvature R6 of the image side surface of the third lens satisfy: 0.5 < (R5 + R6) / (R5 - R6) < 0.8.

[0010] More preferably, the Abbe number Vd1 of the first lens, the Abbe number Vd2 of the second lens, the Abbe number Vd3 of the third lens, and the Abbe number Vd4 of the fourth lens satisfy: 54 < Vd1 < 58, 18 < Vd2 < 25, 54 < Vd3 < 58, 19 < Vd4 < 25; the refractive index Nd1 of the first lens, the refractive index Nd2 of the second lens, the refractive index Nd3 of the third lens, and the refractive index Nd4 of the fourth lens satisfy: 1.52 < Nd1 < 1.56, 1.62 < Nd2 < 1.7, 1.5 < Nd3 < 1.56, 1.62 < Nd4 < 1.68.

[0011] More preferably, the Abbe number Vd5 of the fifth lens and the refractive index Nd5 of the fifth lens satisfy: 35 < Vd5 < 58, 1.52 < Nd5 < 1.58.

[0012] More preferably, the radius of curvature R10 of the image side surface of the fifth lens and the effective focal length f of the optical lens satisfy: 0.35 < R10 / f < 0.65.

[0013] More preferably, the focal length f2 of the second lens and the focal length f3 of the third lens satisfy: -4.1 < f2 / f3 < -1.6.

[0014] The optical lens provided by the present invention adopts five lenses with specific optical powers. Through specific surface shape matching and reasonable optical power distribution, it can improve the imaging quality of the optical lens, reduce aberration, and improve the imaging quality of the optical lens, enabling the lens to have one or more advantages such as a large aperture, miniaturization, and low cost while achieving a good day-night confocal effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which: Figure 1 is a schematic structural diagram of the optical lens in Embodiment 1 of the present invention.

[0016] Figure 2 is an MTF curve graph of the optical lens in Embodiment 1 of the present invention with wavelengths from 470 nm to 650 nm.

[0017] Figure 3 is an MTF curve graph of the optical lens in Embodiment 1 of the present invention with a wavelength of 850 nm.

[0018] Figure 4 It is the defocus curve graph of the optical lens in Embodiment 1 of the present invention with wavelengths from 470nm to 650nm.

[0019] Figure 5 It is the defocus curve graph of the optical lens in Embodiment 1 of the present invention with a wavelength of 850nm.

[0020] Figure 6 It is the distortion curve graph of the optical lens in Embodiment 1 of the present invention.

[0021] Figure 7 It is the astigmatism curve graph of the optical lens in Embodiment 1 of the present invention.

[0022] Figure 8 It is the longitudinal chromatic aberration curve graph of the optical lens in Embodiment 1 of the present invention.

[0023] Figure 9 It is the axial aberration curve graph of the optical lens in Embodiment 1 of the present invention.

[0024] Figure 10 It is the structural schematic diagram of the optical lens in Embodiment 2 of the present invention.

[0025] Figure 11 It is the MTF curve graph of the optical lens in Embodiment 2 of the present invention with wavelengths from 470nm to 650nm.

[0026] Figure 12 It is the MTF curve graph of the optical lens in Embodiment 2 of the present invention with a wavelength of 850nm.

[0027] Figure 13 It is the defocus curve graph of the optical lens in Embodiment 2 of the present invention with wavelengths from 470nm to 650nm.

[0028] Figure 14 It is the defocus curve graph of the optical lens in Embodiment 2 of the present invention with a wavelength of 850nm.

[0029] Figure 15 It is the distortion curve graph of the optical lens in Embodiment 2 of the present invention.

[0030] Figure 16 It is the astigmatism curve graph of the optical lens in Embodiment 2 of the present invention.

[0031] Figure 17 It is the longitudinal chromatic aberration curve graph of the optical lens in Embodiment 2 of the present invention.

[0032] Figure 18 It is the axial aberration curve graph of the optical lens in Embodiment 2 of the present invention.

[0033] Figure 19Schematic diagram of the optical lens in Embodiment 3 of the present invention.

[0034] Figure 20 MTF curve graph of the optical lens in Embodiment 3 of the present invention with wavelengths from 470 nm to 650 nm.

[0035] Figure 21 MTF curve graph of the optical lens in Embodiment 3 of the present invention with a wavelength of 850 nm.

[0036] Figure 22 Defocus curve graph of the optical lens in Embodiment 3 of the present invention with wavelengths from 470 nm to 650 nm.

[0037] Figure 23 Defocus curve graph of the optical lens in Embodiment 3 of the present invention with a wavelength of 850 nm.

[0038] Figure 24 Distortion curve graph of the optical lens in Embodiment 3 of the present invention.

[0039] Figure 25 Astigmatism curve graph of the optical lens in Embodiment 3 of the present invention.

[0040] Figure 26 Magnification chromatic aberration curve graph of the optical lens in Embodiment 3 of the present invention.

[0041] Figure 27 Axial aberration curve graph of the optical lens in Embodiment 3 of the present invention.

[0042] Figure 28 Schematic diagram of the optical lens in Embodiment 4 of the present invention.

[0043] Figure 29 MTF curve graph of the optical lens in Embodiment 4 of the present invention with wavelengths from 470 nm to 650 nm.

[0044] Figure 30 MTF curve graph of the optical lens in Embodiment 4 of the present invention with a wavelength of 850 nm.

[0045] Figure 31 Defocus curve graph of the optical lens in Embodiment 4 of the present invention with wavelengths from 470 nm to 650 nm.

[0046] Figure 32 Defocus curve graph of the optical lens in Embodiment 4 of the present invention with a wavelength of 850 nm.

[0047] Figure 33 Distortion curve graph of the optical lens in Embodiment 4 of the present invention.

[0048] Figure 34 Astigmatism curve graph of the optical lens in Embodiment 4 of the present invention.

[0049] Figure 35 This is the chromatic aberration magnification curve graph of the optical lens in Embodiment 4 of the present invention.

[0050] Figure 36 This is the axial aberration curve graph of the optical lens in Embodiment 4 of the present invention.

[0051] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. Specific Embodiments

[0052] To better understand the present application, more detailed descriptions of various aspects of the present application will be made with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of the embodiments of the present application and do not limit the scope of the present application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0053] It should be noted that in this specification, the expressions such as first, second, third, etc. are only used to distinguish one feature from another feature and do not represent any limitation on the features. Therefore, without departing from the teachings of the present invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0054] In the drawings, for the sake of clarity, the thickness, dimensions, and shape of the lenses have been slightly exaggerated. Specifically, the spherical or aspherical shapes shown in the drawings are shown by way of example. That is, the spherical or aspherical shapes are not limited to the spherical or aspherical shapes shown in the drawings. The drawings are only examples and are not drawn to an exact scale.

[0055] In this document, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the position of the concave surface is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object being photographed is called the object side surface of the lens, and the surface of each lens closest to the imaging surface is called the image side surface of the lens.

[0056] It should also be understood that the terms "comprise", "comprising", "have", "including" and / or "containing", when used in this specification, denote the presence of the stated features, elements and / or components, but do not preclude the presence or addition of one or more other features, elements, components and / or combinations thereof. In addition, when an expression such as "at least one of..." appears after a list of listed features, it modifies the entire list of listed features rather than an individual element in the list. In addition, when describing embodiments of the present application, the use of "may" means "one or more embodiments of the present application". Also, the term "exemplary" is intended to refer to an example or illustration.

[0057] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It should also be understood that terms (such as those defined in a common dictionary) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0058] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments may be combined with each other. The present application will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0059] The optical lens provided by the embodiment of the present invention is a day-night confocal lens, which can achieve confocal for wavelengths of 470 nm - 650 nm and 850 nm, and the defocus amount ≤ 2 μm. The optical lens of the present invention has a total of five lenses, which sequentially include: a first lens, a second lens, a third lens, a fourth lens, and a fifth lens along the optical axis from the object side to the imaging surface.

[0060] In some embodiments, the first lens may have a positive optical power, its object side may be concave or convex, and its image side is convex. The second lens may have a negative optical power, its object side is convex, and its image side is concave. The third lens may have a positive optical power, its object side is convex, and its image side is convex. The fourth lens may have a negative optical power, its object side is concave, and its image side is convex. The fifth lens may have a negative optical power, its object side may be concave or convex, and its image side is concave near the optical axis.

[0061] In some embodiments, the optical lens may further include a diaphragm, and the diaphragm may be located between the first lens and the second lens or between the second lens and the third lens. It can be understood that the diaphragm is used to limit the amount of incident light to change the brightness of the image.

[0062] In some embodiments, the optical lens may further include a filter, which may be disposed between the fifth lens and the imaging surface. The filter is used to filter out interfering light and prevent the interfering light from reaching the imaging surface of the optical lens and affecting normal imaging.

[0063] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: 1.1 < f1 / f < 1.4. Meeting the above conditions, the first lens is moderately focused, which can balance the aberration contributions of the front group and the rear group and avoid the deterioration of the image quality in the marginal field of view.

[0064] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: -6.8 < f5 / f < -0.75. Meeting the above conditions, the optical power of the fifth lens is reasonably distributed, which is beneficial to correcting the remaining aberration generated by the front lenses and improving the resolution.

[0065] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 0.5 < f3 / f < 0.81. Meeting the above conditions, the third lens further converges the incident light at the front end, which is beneficial to correcting the aberration and distortion in the marginal field of view brought by the front lens group, making the lens have a small distortion and capable of providing a high-definition imaging effect.

[0066] In some embodiments, the overall length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 1.45 < TTL / f < 1.5. Meeting the above conditions, the length of the lens can be effectively limited, which is beneficial to realizing the miniaturization of the optical lens.

[0067] In some embodiments, the effective focal length f of the optical lens, the maximum field of view FOV of the optical lens, and the true image height IH corresponding to the maximum field of view of the optical lens satisfy: 49° < (f × FOV) / IH < 50°. Meeting the above range, by reasonably restricting the relationship between the focal length, the field of view angle, and the image height of the optical lens, the optical lens has good optical performance and can well capture the details of the object to be photographed.

[0068] In some embodiments, the radius of curvature R5 of the object side surface of the third lens and the radius of curvature R6 of the image side surface of the third lens satisfy: 0.5 < (R5 + R6) / (R5 - R6) < 0.8. Meeting the above conditions, the radius of curvature of the object side surface and the image side surface of the third lens near the optical axis are reasonably controlled, which is beneficial to controlling the shape of the third lens, optimizing the aberration balance of the lens group, and improving the imaging quality.

[0069] In some embodiments, the Abbe number Vd1 of the first lens, the Abbe number Vd2 of the second lens, the Abbe number Vd3 of the third lens, and the Abbe number Vd4 of the fourth lens satisfy: 54 < Vd1 < 58, 18 < Vd2 < 25, 54 < Vd3 < 58, 19 < Vd4 < 25; the refractive index Nd1 of the first lens, the refractive index Nd2 of the second lens, the refractive index Nd3 of the third lens, and the refractive index Nd4 of the fourth lens satisfy: 1.52 < Nd1 < 1.56, 1.62 < Nd2 < 1.7, 1.5 < Nd3 < 1.56, 1.62 < Nd4 < 1.68. Meeting the above conditions, pairing a low Abbe number lens with a high Abbe coefficient lens can cancel axial chromatic aberration, which is beneficial to achieving infrared confocal.

[0070] In some embodiments, the Abbe number Vd5 and the refractive index Nd5 of the fifth lens satisfy: 35 < Vd5 < 58, 1.52 < Nd5 < 1.58. Meeting the above conditions, using a high Abbe coefficient and low infrared dispersion material in the last lens can reduce the 850nm focal shift and correct infrared resolution.

[0071] In some embodiments, the radius of curvature R10 of the image side surface of the fifth lens and the effective focal length f of the optical lens satisfy: 0.35 < R10 / f < 0.65. Meeting the above range, by reasonably setting the radius of curvature of the image side surface of the fifth lens, it is beneficial to balance the aberration generated by the front lens, and at the same time beneficial to collecting the light rays in the marginal field of view, improving the imaging quality of the marginal field of view and increasing the imaging area of the optical lens.

[0072] In some embodiments, the focal length f2 of the second lens and the focal length f3 of the third lens satisfy: -4.1 < f2 / f3 < -1.6. Meeting the above range, reasonably distributing the optical power of the second lens and the third lens is beneficial to the correction of chromatic aberration and improves the resolution ability of the system.

[0073] In some embodiments, the true image height IH corresponding to the maximum field of view angle of the optical lens and the effective focal length f of the optical lens satisfy: 1.3 < IH / f < 1.4; the total optical length TTL of the optical lens and the true image height IH corresponding to the maximum field of view angle of the optical lens satisfy: 1 < TTL / IH < 1.15. Meeting the above conditions can better achieve the miniaturization of the lens, and at the same time ensure that the lens has a larger image plane under the same total length, and can match a larger size imaging chip to achieve high-definition imaging.

[0074] In some embodiments, the focal length f2 of the second lens and the effective focal length f of the optical lens satisfy: -2.1 < f2 / f < -1.3. Meeting the above conditions, the negative lens of the second lens can adjust the angle of the chief ray and reduce the lens distortion.

[0075] In some embodiments, the focal length f4 of the fourth lens and the effective focal length f of the optical lens satisfy: -3.5 < f4 / f < -1.2. Meeting the above conditions, by reasonably setting the focal length of the fourth lens, it is beneficial to the smooth transition of light, facilitates the correction of astigmatism and field curvature, improves the imaging quality of the optical lens, and ensures the stability of the optical system.

[0076] In some embodiments, the focal length f1 of the first lens and the focal length f2 of the second lens satisfy: -0.9 < f1 / f2 < -0.65. Meeting the above conditions can enable the first lens and the second lens to form chromatic aberration compensation, and helps to compress the system length and balance the field curvature.

[0077] In some embodiments, the total optical length TTL of the optical lens and the sum ∑CT of the central thicknesses of the first lens to the fifth lens along the optical axis satisfy: 0.6 < ∑CT / TTL < 0.71. Meeting the above conditions can effectively compress the total length of the optical lens, and is beneficial to the structural design and production process of the optical lens.

[0078] In some embodiments, the optical lens satisfies the following conditional expressions: 3.4mm < f < 3.6mm; 66° < FOV < 68°; 5.1mm < TTL < 5.25mm; 4.6mm < IH < 4.8mm; 1.95 < Fno < 2. In the above conditional expressions, f represents the effective focal length of the optical lens, FOV represents the maximum field of view angle of the optical lens, TTL represents the total optical length of the optical lens, IH represents the true image height corresponding to the maximum half field of view angle of the optical lens, and Fno represents the aperture value of the optical lens. Meeting the above ranges, the optical lens has at least one or more advantages such as a large aperture and miniaturization.

[0079] In some embodiments, the lens material in the optical lens provided by the present invention can be glass or plastic. When the lens material is plastic, the production cost can be effectively reduced. On the other hand, when the lens material is glass, the geometric chromatic aberration of the optical system can be effectively corrected by the low dispersion characteristic of the glass itself. The first lens, the second lens, the third lens, the fourth lens, and the fifth lens in the optical lens provided by the present invention all adopt plastic lenses to reduce costs.

[0080] In some embodiments, the first lens, the second lens, the third lens, the fourth lens, and the fifth lens can adopt spherical lenses or aspherical lenses. Compared with the spherical structure, the aspherical structure can effectively reduce the aberration of the optical system, thereby reducing the number of lenses and the size of the lenses, and better realizing the miniaturization of the lens. More specifically, the first lens, the second lens, the third lens, the fourth lens, and the fifth lens of the present invention can all adopt aspherical lenses, which can effectively reduce the aberration of the optical lens, thereby reducing the number of lenses and the size of the lenses, and better realizing the miniaturization of the lens.

[0081] In various embodiments of the present invention, when the lens is an aspherical lens, the aspherical surface shapes of the optical lens satisfy the following equation: ; where z is the distance between the surface and the vertex of the surface in the optical axis direction, h is the distance from the optical axis to the surface, c is the curvature of the vertex of the surface, K is the conic coefficient, and B, C, D, E, F, G, H are the surface coefficients of the fourth, sixth, eighth, tenth, twelfth, fourteenth, and sixteenth orders respectively.

[0082] The present invention will be further described in multiple embodiments below. In each embodiment, the thickness, curvature radius, and material selection of each lens in the optical lens are partially different. For specific differences, please refer to the parameter tables of each embodiment. The following embodiments are only preferred embodiments of the present invention, but the embodiments of the present invention are not limited only by the following embodiments. Any other changes, substitutions, combinations, or simplifications made without departing from the innovative points of the present invention should be regarded as equivalent replacement methods and are included in the protection scope of the present invention.

[0083] Embodiment 1 Please refer to Figure 1 , which shows a schematic structural diagram of the optical lens provided in Embodiment 1 of the present invention. The optical lens sequentially includes, along the optical axis from the object side to the imaging surface: a first lens L1, a diaphragm ST, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, and a filter G1.

[0084] Among them, the first lens L1 has a positive optical power, its object side S1 is a convex surface, and its image side S2 is a convex surface; The second lens L2 has a negative optical power, its object side S3 is a convex surface, and its image side S4 is a concave surface; The third lens L3 has a positive optical power, its object side S5 is a convex surface, and its image side S6 is a convex surface; The fourth lens L4 has a negative optical power, its object side S7 is a concave surface, and its image side S8 is a convex surface; The fifth lens L5 has a negative optical power, its object side S9 is a convex surface near the optical axis, and its image side S10 is a concave surface near the optical axis; The object side S11 and the image side S12 of the filter G1 are both flat surfaces; The imaging surface S13 is a flat surface.

[0085] The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 all adopt plastic aspherical lenses.

[0086] The relevant parameters of each lens in the optical lens in Embodiment 1 are shown in Table 1-1.

[0087] Table 1-1 The surface profile parameters of the aspherical lens of the optical lens in Example 1 are shown in Table 1-2.

[0088] Table 1-2 In this embodiment, the MTF curve graphs of the optical lens 100 at wavelengths from 470 nm to 650 nm, the MTF curve graph at wavelength 850 nm, the defocus curve graphs at wavelengths from 470 nm to 650 nm, the defocus curve graph at wavelength 850 nm, the distortion curve graph, the astigmatism curve graph, the lateral color aberration curve graph, and the axial aberration curve graph are respectively as Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Figure 9 shown.

[0089] Figure 2 shows the MTF (Modulation Transfer Function) curve graph of Example 1 at wavelengths from 470 nm to 650 nm, which represents the modulation of the lens imaging at different spatial frequencies in each field of view at wavelengths from 470 nm to 650 nm. The horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. It can be seen from the figure that the MTF values of this embodiment are all above 0.4 in the entire field of view. In the range of 0 - 180 lp / mm, the MTF curve smoothly decreases uniformly from the center to the edge field of view, and has good imaging quality and good detail resolution ability in both low-frequency and high-frequency cases.

[0090] Figure 3 shows the MTF curve graph of Example 1 at wavelength 850 nm, which represents the modulation of the lens imaging at different spatial frequencies in each field of view at wavelength 850 nm. The horizontal axis represents the spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. It can be seen from the figure that the MTF values of this embodiment are all above 0.38 in the entire field of view. In the range of 0 - 180 lp / mm, the MTF curve smoothly decreases uniformly from the center to the edge field of view, and has good imaging quality and good detail resolution ability in both low-frequency and high-frequency cases.

[0091] Figure 4The defocus curve graph of Example 1 with a wavelength ranging from 470 nm to 650 nm is shown, which represents the modulation transfer function (MTF) of the lens imaging at a spatial frequency of 92 lp / mm. The horizontal axis represents the defocus offset (unit: mm), and the vertical axis represents the OTF modulus value. It can be seen from the graph that the OTF value at the focus of the central field of view is greater than 80%, indicating that the lens has good resolution.

[0092] Figure 5 The defocus curve graph of Example 1 with a wavelength of 850 nm is shown, which represents the modulation transfer function (MTF) of the lens imaging at a spatial frequency of 92 lp / mm. The horizontal axis represents the defocus offset (unit: mm), and the vertical axis represents the OTF modulus value. It can be seen from the graph that the OTF value at the focus of the central field of view is greater than 80%, indicating that the lens has good resolution.

[0093] Figure 6 The distortion curve graph of Example 1 is shown, which represents the distortion at different image heights on the imaging plane. The horizontal axis represents the distortion value (unit: %), and the vertical axis represents the image height (unit: mm). It can be seen from the graph that the distortion of the optical lens is controlled within 0 - 1.5%, indicating that the distortion of the optical lens 100 is well corrected.

[0094] Figure 7 The astigmatism curve graph of Example 1 is shown, which represents the astigmatism of light rays in the meridional image plane and the sagittal image plane. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the image height (unit: mm). It can be seen from the graph that the astigmatism of the meridional image plane and the sagittal image plane is controlled within ±0.1 mm, indicating that the optical lens 100 can better correct astigmatism.

[0095] Figure 8 The longitudinal chromatic aberration curve graph of Example 1 is shown, which represents the chromatic aberration at different image heights on the imaging plane for each wavelength relative to the central wavelength (555 nm). The horizontal axis represents the chromatic aberration value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field of view angle. It can be seen from the graph that the chromatic aberration between the longest wavelength and the shortest wavelength is controlled within ±1.5 μm, indicating that the optical lens 100 can better correct chromatic aberration.

[0096] Figure 9 The axial aberration curve graph of Example 1 is shown, which represents the aberration of each wavelength on the optical axis at the imaging plane. The horizontal axis represents the axial aberration value (unit: mm), and the vertical axis represents the normalized pupil radius. It can be seen from the graph that the offset of the axial aberration is controlled within ±0.03 mm, indicating that the optical lens 100 can better correct axial aberration.

[0097] Example 2 Please refer to Figure 10, which shows the structural schematic diagram of the optical lens provided in Embodiment 2 of the present invention. Compared with Embodiment 1, the main differences are as follows: the object side S1 of the first lens L1 is a concave surface; the object side S9 of the fifth lens L5 is a concave surface; the optical parameters such as the curvature radius and lens thickness of each lens surface are different.

[0098] The relevant parameters of each lens in the optical lens of Embodiment 2 are shown in Table 2-1.

[0099] Table 2-1 The surface type parameters of the aspherical lens in the optical lens of Embodiment 2 are shown in Table 2-2.

[0100] Table 2-2 In this embodiment, the MTF curve graphs of the optical lens 200 at wavelengths from 470 nm to 650 nm, the MTF curve graph at a wavelength of 850 nm, the defocus curve graphs at wavelengths from 470 nm to 650 nm, the defocus curve graph at a wavelength of 850 nm, the distortion curve graph, the astigmatism curve graph, the lateral chromatic aberration curve graph, and the axial aberration curve graph are respectively as Figure 11 , Figure 12 , Figure 13 , Figure 14 , Figure 15 , Figure 16 , Figure 17 , Figure 18 shown.

[0101] From Figure 11 it can be seen that the MTF value of this embodiment is above 0.45 in the entire field of view. In the range of 0 to 180 lp / mm, the MTF curve smoothly decreases uniformly from the center to the edge of the field of view, and it has good imaging quality and good detail resolution ability in both low-frequency and high-frequency cases.

[0102] From Figure 12 it can be seen that the MTF value of this embodiment is above 0.3 in the entire field of view. In the range of 0 to 180 lp / mm, the MTF curve smoothly decreases uniformly from the center to the edge of the field of view, and it has good imaging quality and good detail resolution ability in both low-frequency and high-frequency cases.

[0103] From Figure 13 it can be seen that the OTF value at the center of the field of view at the focus is greater than 80%, indicating that the lens has good resolution.

[0104] From Figure 14 it can be seen that the OTF value at the center of the field of view at the focus is greater than 80%, indicating that the lens has good resolution.

[0105] It can be seen from Figure 15 that the distortion of the optical lens is controlled within 0 - 1.5%, indicating that the distortion of the optical lens 200 is well corrected.

[0106] It can be seen from Figure 16 that the astigmatism of the meridional image plane and the sagittal image plane is controlled within ±0.15 mm, indicating that the optical lens 200 can correct astigmatism well.

[0107] It can be seen from Figure 17 that the chromatic aberration between the longest wavelength and the shortest wavelength is controlled within ±1.5 μm, indicating that the optical lens 200 can correct chromatic aberration well.

[0108] It can be seen from Figure 18 that the offset of the axial aberration is controlled within ±0.03 mm, indicating that the optical lens 200 can correct axial aberration well.

[0109] Embodiment 3 Please refer to Figure 19 , which shows the structural schematic diagram of the optical lens provided in Embodiment 3 of the present invention. Compared with Embodiment 1, the main differences are: the aperture stop ST is arranged between the second lens L2 and the third lens L3; the object side surface S1 of the first lens L1 is a concave surface; the optical parameters such as the curvature radius and lens thickness of each lens surface are different.

[0110] The relevant parameters of each lens in the optical lens of Embodiment 3 are shown in Table 3 - 1.

[0111] Table 3 - 1 The aspheric lens surface type parameters of the optical lens in Embodiment 3 are shown in Table 3 - 2.

[0112] Table 3 - 2 In this embodiment, the MTF curve graphs of the optical lens 300 at wavelengths from 470 nm to 650 nm, the MTF curve graph at wavelength 850 nm, the defocus curve graphs at wavelengths from 470 nm to 650 nm, the defocus curve graph at wavelength 850 nm, the distortion curve graph, the astigmatism curve graph, the lateral chromatic aberration curve graph, and the axial aberration curve graph are respectively as Figure 20 , Figure 21 , Figure 22 , Figure 23 , Figure 24 , Figure 25 , Figure 26 , Figure 27 shown.

[0113] It can be seen from Figure 20It can be seen that the MTF value of this embodiment is above 0.4 within the entire field of view. In the range of 0 to 180 lp / mm, the MTF curve smoothly decreases uniformly from the center to the edge of the field of view, and it has good imaging quality and good detail resolution ability in both low-frequency and high-frequency cases.

[0114] From Figure 21 It can be seen that the MTF value of this embodiment is above 0.2 within the entire field of view. In the range of 0 to 180 lp / mm, the MTF curve smoothly decreases uniformly from the center to the edge of the field of view, and it has good imaging quality and good detail resolution ability in both low-frequency and high-frequency cases.

[0115] From Figure 22 It can be seen that the OTF value of the central field of view at the focus is greater than 80%, indicating that the lens has good resolution.

[0116] From Figure 23 It can be seen that the OTF value of the central field of view at the focus is greater than 80%, indicating that the lens has good resolution.

[0117] From Figure 24 It can be seen that the distortion of the optical lens is controlled within 0 to 2%, indicating that the distortion of the optical lens 300 is well corrected.

[0118] From Figure 25 It can be seen that the astigmatism between the meridional image plane and the sagittal image plane is controlled within ±0.1 mm, indicating that the optical lens 300 can correct astigmatism well.

[0119] From Figure 26 It can be seen that the chromatic aberration between the longest wavelength and the shortest wavelength is controlled within ±1.5 μm, indicating that the optical lens 300 can correct chromatic aberration well.

[0120] From Figure 27 It can be seen that the offset of the axial aberration is controlled within ±0.02 mm, indicating that the optical lens 300 can correct axial aberration well.

[0121] Embodiment 4 Please refer to Figure 28 , which shows the structural schematic diagram of the optical lens provided in Embodiment 4 of the present invention. Compared with Embodiment 1, the main differences are: the aperture stop ST is disposed between the second lens L2 and the third lens L3; the object side surface S9 of the fifth lens L5 is concave; the optical parameters such as the curvature radius and lens thickness of each lens surface are different.

[0122] The relevant parameters of each lens in the optical lens in Embodiment 4 are shown in Table 4-1.

[0123] Table 4-1 The surface type parameters of the aspherical lens of the optical lens in Embodiment 4 are shown in Table 4-2.

[0124] Table 4-2 In this embodiment, the MTF curve graphs of the optical lens 400 at wavelengths from 470 nm to 650 nm, the MTF curve graph at a wavelength of 850 nm, the defocus curve graphs at wavelengths from 470 nm to 650 nm, the defocus curve graph at a wavelength of 850 nm, the distortion curve graph, the astigmatism curve graph, the lateral color aberration curve graph, and the axial aberration curve graph are respectively as Figure 29 , Figure 30 , Figure 31 , Figure 32 , Figure 33 , Figure 34 , Figure 35 , Figure 36 shown.

[0125] From Figure 29 it can be seen that the MTF value of this embodiment is above 0.48 within the entire field of view. In the range of 0 to 180 lp / mm, the MTF curve smoothly decreases uniformly from the center to the edge of the field of view, and it has good imaging quality and good detail resolution ability in both low-frequency and high-frequency cases.

[0126] From Figure 30 it can be seen that the MTF value of this embodiment is above 0.35 within the entire field of view. In the range of 0 to 180 lp / mm, the MTF curve smoothly decreases uniformly from the center to the edge of the field of view, and it has good imaging quality and good detail resolution ability in both low-frequency and high-frequency cases.

[0127] From Figure 31 it can be seen that the OTF value at the center of the field of view at the focal point is greater than 80%, indicating that the lens has good resolving power.

[0128] From Figure 32 it can be seen that the OTF value at the center of the field of view at the focal point is greater than 80%, indicating that the lens has good resolving power.

[0129] From Figure 33 it can be seen that the distortion of the optical lens is controlled within 0 to 1.5%, indicating that the distortion of the optical lens 400 is well corrected.

[0130] From Figure 34 it can be seen that the astigmatism between the meridional image plane and the sagittal image plane is controlled within ±0.05 mm, indicating that the optical lens 400 can better correct astigmatism.

[0131] From Figure 35 it can be seen that the color difference between the longest wavelength and the shortest wavelength is controlled within ±1 μm, indicating that the optical lens 400 can correct chromatic aberration well.

[0132] From Figure 36 it can be seen that the offset of the axial aberration is controlled within ±0.02 mm, indicating that the optical lens 400 can correct axial aberration well.

[0133] Please refer to Table 5 for the optical characteristics corresponding to the above embodiments, including the effective focal length f of the optical lens, the total optical length TTL, the aperture value Fno, the true image height IH corresponding to the maximum field of view angle, and the maximum field of view angle FOV, as well as the values corresponding to each conditional expression in each embodiment.

[0134] Table 5 In summary of the above embodiments, the optical lens provided by the present invention uses five lenses with specific optical powers. Through specific surface shape matching and reasonable optical power distribution, it can improve the imaging quality of the optical lens, reduce aberration, and improve the imaging quality of the optical lens, enabling the lens to achieve a good day-night confocal effect with a defocus amount ≤ 2 μm. At the same time, it also has one or more advantages such as a large aperture, miniaturization, and low cost.

[0135] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0136] The above-described embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims

1. An optical lens, comprising five lenses, characterized in that: It sequentially includes from the object side to the imaging surface along the optical axis: A first lens with positive optical power, whose image side is convex; A second lens with negative optical power, whose object side is convex and whose image side is concave; A third lens with positive optical power, whose object side is convex and whose image side is convex; A fourth lens with negative optical power, whose object side is concave and whose image side is convex; A fifth lens with negative optical power, whose image side is concave near the optical axis; Wherein, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: 1.1 < f1 / f < 1.

4.

2. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: -6.8 < f5 / f < -0.

75.

3. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 0.5 < f3 / f < 0.

81.

4. The optical lens according to claim 1, characterized in that: The overall optical length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 1.45 < TTL / f < 1.

5.

5. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens, the maximum field of view FOV of the optical lens, and the true image height IH corresponding to the maximum field of view of the optical lens satisfy: 49° < (f × FOV) / IH < 50°.

6. The optical lens according to claim 1, characterized in that: The curvature radius R5 of the object side of the third lens and the curvature radius R6 of the image side of the third lens satisfy: 0.5 < (R5 + R6) / (R5 - R6) < 0.

8.

7. The optical lens according to claim 1, characterized in that: The Abbe number Vd1 of the first lens, the Abbe number Vd2 of the second lens, the Abbe number Vd3 of the third lens, and the Abbe number Vd4 of the fourth lens satisfy: 54 < Vd1 < 58, 18 < Vd2 < 25, 54 < Vd3 < 58, 19 < Vd4 < 25; the refractive index Nd1 of the first lens, the refractive index Nd2 of the second lens, the refractive index Nd3 of the third lens, and the refractive index Nd4 of the fourth lens satisfy: 1.52 < Nd1 < 1.56, 1.62 < Nd2 < 1.7, 1.5 < Nd3 < 1.56, 1.62 < Nd4 < 1.

68.

8. The optical lens according to claim 1, characterized in that: The Abbe number Vd5 of the fifth lens and the refractive index Nd5 of the fifth lens satisfy: 35 < Vd5 < 58, 1.52 < Nd5 < 1.

58.

9. The optical lens according to claim 1, characterized in that: The curvature radius R10 of the image side of the fifth lens and the effective focal length f of the optical lens satisfy: 0.35 < R10 / f < 0.

65.

10. The optical lens according to claim 1, characterized in that: The focal length f2 of the second lens and the focal length f3 of the third lens satisfy: -4.1 < f2 / f3 < -1.6.

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