Optical system

Abstract

The present application relates to an optical system, comprising a lens barrel, an imaging lens group and a plurality of spacer elements, the imaging lens group sequentially comprises, along the optical axis from the object side to the image side: a first lens with negative refractive power, a second lens with negative refractive power, a third lens with positive refractive power, a fourth lens with positive refractive power, a fifth lens with negative refractive power, a sixth lens with positive refractive power and a seventh lens with negative refractive power, a total of seven lenses with refractive power; The optical system satisfies: 144.00<=FOV<=164.60; 2.50<=EP23 / (T23-CT3)<=3.63; 4.80<=EP23 / (T34-CT2)<=6.22. The present application can solve the problems of imaging degradation, poor structural reliability and insufficient thermal stability of large field of view optical lens, and realize high performance stable imaging under large field of view and complex environment.

Description

Technical Field

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

[0002] Traditional optical lenses have many limitations, especially in wide field-of-view applications. They are difficult to balance excellent optical imaging performance with reliable environmental adaptability, and cannot meet the comprehensive requirements of security monitoring and other fields for wide field of view, high image quality and high stability.

[0003] In many surveillance scenarios requiring a wide field of view, conventional optical lenses struggle to achieve this, such as panoramic surveillance and large-scale security applications. These scenarios urgently need optical lenses capable of covering a greater area to reduce blind spots and improve surveillance efficiency.

[0004] However, wide-field-of-view optical lenses have extremely large incident angles of light at the edges, making them highly sensitive to the positional accuracy of optical components. Even minor assembly errors can lead to severe astigmatism, coma, and distortion. Furthermore, in traditional lenses, excessive or thick air gaps in the lens and spacer arrangement can easily cause air convection and temperature gradients due to changes in ambient temperature, resulting in thermal distortion. This degrades imaging performance, making it difficult to maintain stable image quality over a wide temperature range and failing to meet the demands of complex environments such as alternating high and low temperatures. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention aims to provide an optical system that solves the problems of image degradation, poor structural reliability, and insufficient thermal stability in large field-of-view optical lenses, thereby achieving high-performance and stable imaging in large field-of-view and complex environments.

[0006] To achieve the above-mentioned objective, the present invention provides an optical system comprising a lens barrel having a receiving space, wherein an imaging lens group and a plurality of spacer elements are disposed within the receiving space.

[0007] The imaging lens group includes, in sequence along the optical axis from the object side to the image side: a first lens with negative optical power, a second lens with negative optical power, a third lens with positive optical power, a fourth lens with positive optical power, a fifth lens with negative optical power, a sixth lens with positive optical power, and a seventh lens with negative optical power, for a total of seven lenses with optical power.

[0008] The plurality of spacers include: a second spacer element disposed on the image side of the second lens and in at least partial contact with the image side surface of the second lens; and a third spacer element disposed on the image side of the third lens and in at least partial contact with the image side surface of the third lens.

[0009] The optical system satisfies:

[0010] 144.00°≤FOV≤164.60°;

[0011] 2.50≤EP23 / (T23-CT3)≤3.63; 4.80≤EP23 / (T34-CT2)≤6.22;

[0012] Wherein, FOV is the maximum field of view of the optical system, T23 is the air gap between the second lens and the third lens on the optical axis, T34 is the air gap between the third lens and the fourth lens on the optical axis, CT2 is the center thickness of the second lens, CT3 is the center thickness of the third lens, and EP23 is the spacing distance between the second spacer element and the third spacer element along the optical axis.

[0013] According to one technical solution of the present invention, the plurality of spacer elements includes: a sixth spacer element, which is disposed on the image side of the sixth lens and at least partially contacts the image side of the sixth lens;

[0014] The optical system satisfies: 5.91≤(CP6+CT7) / T67≤19.78;

[0015] Wherein, CP6 is the maximum thickness of the sixth spacer element along the optical axis, CT7 is the center thickness of the seventh lens, and T67 is the air gap between the sixth and seventh lenses on the optical axis.

[0016] According to one technical solution of the present invention, the plurality of spacer elements includes: a first spacer element, which is disposed on the image side of the first lens and at least partially contacts the image side side of the first lens;

[0017] The optical system satisfies: 7.17≤(D1s-D2s) / CT2≤9.28; 2.68≤DT11 / DT22≤3.04;

[0018] Wherein, D1s is the outer diameter of the object side of the first spacer element, D2s is the outer diameter of the object side of the second spacer element, CT2 is the center thickness of the second lens, DT11 is the effective radius of the object side of the first lens, and DT22 is the effective radius of the image side of the second lens.

[0019] According to one technical solution of the present invention, the optical system satisfies: 3.53≤R6 / d3s≤6.68; 7.07≤f3 / (CT3+CP3)≤8.76;

[0020] Wherein, R6 is the radius of curvature of the image side of the third lens, d3s is the inner diameter of the object side of the third spacer element, f3 is the effective focal length of the third lens, CT3 is the center thickness of the third lens, and CP3 is the maximum thickness of the third spacer element along the optical axis.

[0021] According to one technical solution of the present invention, the plurality of spacer elements includes: a fifth spacer element, which is disposed on the image side of the fifth lens and at least partially contacts the image side side of the fifth lens;

[0022] The optical system satisfies: -3.87 < d5s / (f5+f6) ≤ -1.77; 2.69 ≤ CT5 / (CP5+T56) ≤ 5.42;

[0023] Wherein, d5s is the inner diameter of the object side of the fifth spacer element; f5 is the effective focal length of the fifth lens; f6 is the effective focal length of the sixth lens; CT5 is the center thickness of the fifth lens; CP5 is the maximum thickness of the fifth spacer element along the optical axis; and T56 is the air gap between the fifth lens and the sixth lens on the optical axis.

[0024] According to one technical solution of the present invention, for any two adjacent spacers among the plurality of spacers, the on-axis distance from the second spacer to the third spacer is the largest, and the optical system satisfies: 1.19≤T23 / (d2m-d3s)≤1.80; 19.16<(DT22-DT31) / CP3≤25.82;

[0025] Wherein, T23 is the air gap between the second lens and the third lens on the optical axis, d2m is the inner diameter of the image side of the second spacer element, d3s is the inner diameter of the object side of the third spacer element, DT31 is the effective radius of the object side of the third lens, DT22 is the effective radius of the image side of the second lens, and CP3 is the maximum thickness of the third spacer element along the optical axis.

[0026] According to one technical solution of the present invention, the plurality of spacer elements includes: a sixth spacer element, which is disposed on the image side of the sixth lens and at least partially contacts the image side of the sixth lens;

[0027] The optical system satisfies: -2.60≤f7 / d6s≤-1.25; -3.50≤R13 / d6m≤-2.08;

[0028] Wherein, d6m is the inner diameter of the image side of the sixth spacer element, d6s is the inner diameter of the object side of the sixth spacer element, f7 is the effective focal length of the seventh lens, and R13 is the radius of curvature of the object side of the seventh lens.

[0029] According to one technical solution of the present invention, the plurality of spacer elements includes: a fourth spacer element disposed on the image side of the fourth lens and at least partially in contact with the image side surface of the fourth lens; and a fifth spacer element disposed on the image side of the fifth lens and at least partially in contact with the image side surface of the fifth lens.

[0030] The optical system satisfies: 2.63≤EP45 / (T45+T56)≤4.87;

[0031] Wherein, EP45 is the spacing distance between the fourth spacer element and the fifth spacer element along the optical axis, T45 is the air gap between the fourth lens and the fifth lens on the optical axis, and T56 is the air gap between the fifth lens and the sixth lens on the optical axis.

[0032] According to one technical solution of the present invention, the plurality of spacer elements includes: a first spacer element disposed on the image side of the first lens and at least partially in contact with the image side of the first lens; and a second auxiliary spacer element disposed on the image side of the second spacer element and at least partially in contact with the image side of the second spacer element.

[0033] The optical system satisfies: 68.98≤(CP2+CP2b) / CP1≤85.77; -3.37≤f2 / (d2bm-d2bs)≤-2.32;

[0034] Wherein, CP1 is the maximum thickness of the first spacer element along the optical axis, CP2 is the maximum thickness of the second spacer element along the optical axis, CP2b is the maximum thickness of the second auxiliary spacer element along the optical axis, f2 is the effective focal length of the second lens, d2bs is the inner diameter of the object side of the second auxiliary spacer element, and d2bm is the inner diameter of the image side of the second auxiliary spacer element.

[0035] According to one technical solution of the present invention, the plurality of spacer elements includes: a fourth spacer element disposed on the image side of the fourth lens and at least partially in contact with the image side surface of the fourth lens; and a fifth spacer element disposed on the image side of the fifth lens and at least partially in contact with the image side surface of the fifth lens.

[0036] The optical system satisfies: -2.40≤SAG51 / T45≤-0.73; 1.79≤CT5 / (d5s-d4m)≤4.29;

[0037] Wherein, T45 is the air gap between the fourth lens and the fifth lens on the optical axis, SAG51 is the axial distance between the intersection of the object side surface of the fifth lens and the optical axis and the vertex of the effective radius of the object side surface of the fifth lens, CT5 is the center thickness of the fifth lens, d4m is the inner diameter of the image side surface of the fourth spacer element, and d5s is the inner diameter of the object side surface of the fifth spacer element.

[0038] According to one technical solution of the present invention, the plurality of spacer elements includes: a fifth spacer element, which is disposed on the image side of the fifth lens and at least partially contacts the image side side of the fifth lens;

[0039] The optical system satisfies: 1.40≤(D5m-d5m) / CT6≤1.99;

[0040] Wherein, D5m is the outer diameter of the image-side surface of the fifth spacer element, d5m is the inner diameter of the image-side surface of the fifth spacer element, and CT6 is the center thickness of the sixth lens.

[0041] According to one technical solution of the present invention, the plurality of spacer elements includes: a fifth spacer element disposed on the image side of the fifth lens and at least partially in contact with the image side surface of the fifth lens; and a sixth spacer element disposed on the image side of the sixth lens and at least partially in contact with the image side surface of the sixth lens;

[0042] The optical system satisfies: 14.70≤CT6 / T67≤41.67; 9.31≤EP56 / T67≤23.46;

[0043] Wherein, CT6 is the center thickness of the sixth lens, T67 is the air gap between the sixth lens and the seventh lens on the optical axis, and EP56 is the spacing distance between the fifth spacer element and the sixth spacer element along the optical axis.

[0044] According to one technical solution of the present invention, the plurality of spacing elements includes: a second auxiliary spacing element disposed on the image side of the second spacing element and at least partially in contact with the image side side of the second spacing element; and a third auxiliary spacing element disposed on the image side of the third spacing element and at least partially in contact with the image side side of the third spacing element.

[0045] The optical system satisfies: 1.36≤(CP2b+CP3b) / CT3≤2.14;

[0046] Wherein, CT3 is the center thickness of the third lens, CP2b is the maximum thickness of the second auxiliary spacer element along the optical axis, and CP3b is the maximum thickness of the third auxiliary spacer element along the optical axis.

[0047] According to one technical solution of the present invention, the plurality of spacer elements includes: a sixth spacer element located on the image side of the sixth lens and in at least partial contact with the image side surface of the sixth lens;

[0048] The optical system satisfies: 13.27≤CT6 / (T67+CP6)≤31.25; -3.76≤R14 / R13≤-0.32;

[0049] Wherein, CT6 is the center thickness of the sixth lens, CP6 is the maximum thickness of the sixth spacer element along the optical axis, T67 is the air gap between the sixth lens and the seventh lens on the optical axis, R13 is the radius of curvature of the object side of the seventh lens, and R14 is the radius of curvature of the image side of the seventh lens.

[0050] In the optical system of this invention, the field of view of the optical system is large, the incident angle of the edge rays of the optical system is extremely large, and the optical system is extremely sensitive to the eccentricity and tilt of the lens. It is easy to cause serious astigmatism, coma and distortion due to small assembly errors. By controlling the optical system to meet the parameters 2.50≤EP23 / (T23-CT3)≤3.63 and 4.80≤EP23 / (T34-CT2)≤6.22, the center thickness of the lens and the air gap and spacing of the spacer elements on the optical axis can be controlled. This effectively improves the thickness and rigidity of the support surface between the third and fourth lenses to resist axial and radial impacts, reduce thermal distortion caused by air convection and temperature gradients, avoid excessively small lens peripheral spacing due to insufficient EP23, which increases the risk of edge collision during injection molding or assembly, and prevents insufficient heat dissipation space within the optical system, stress concentration due to thermal expansion and contraction of the lenses, and excessively thin edge thickness of the third lens, which increases the risk of mechanical impact breakage. This ensures that the second and third lenses do not shift under harsh environments (such as vibration and impact) and cause structural failure. As a result, the performance stability of the optical system in a wide temperature range is improved, thereby effectively improving the optical system's resistance to deformation, vibration, and temperature changes. Attached Figure Description

[0051] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments will be briefly described below.

[0052] Figure 1A and Figure 1B A structural layout diagram and schematic diagram of some parameters of an optical system according to the present invention are shown;

[0053] Figure 2A , Figure 2B and Figure 2C Schematic diagrams of three optical systems according to Embodiment 1 of the present invention are shown respectively;

[0054] Figure 2D The chromatic aberration curves of the optical system of Embodiment 1 are shown on the axis in the operating wavelength range of 470-960nm;

[0055] Figure 2E and Figure 2F Astigmatism curves of the optical system in Embodiment 1 are shown for the operating wavelength range of 470-650nm and 920-960nm, respectively.

[0056] Figure 2G and Figure 2H The magnification chromatic aberration curves of the optical system of Embodiment 1 are shown for the operating wavelength range of 470-650nm and the operating wavelength range of 920-960nm, respectively.

[0057] Figure 3A , Figure 3B and Figure 3C Schematic diagrams of three optical systems according to Embodiment 2 of the present invention are shown respectively;

[0058] Figure 3D The chromatic aberration curves of the optical system of Embodiment 2 are shown on the axis in the operating wavelength range of 470-960nm.

[0059] Figure 3E and Figure 3F Astigmatism curves of the optical system in Example 2 are shown for the operating wavelength range of 470-650nm and 920-960nm, respectively.

[0060] Figure 3G and Figure 3H The magnification chromatic aberration curves of the optical system of Embodiment 2 are shown for the operating wavelength range of 470-650nm and the operating wavelength range of 920-960nm, respectively.

[0061] Figure 4A , Figure 4B and Figure 4C Schematic diagrams of three optical systems according to Embodiment 3 of the present invention are shown respectively;

[0062] Figure 4D The chromatic aberration curves of the optical system of Embodiment 3 are shown on the axis in the operating wavelength range of 470-960nm;

[0063] Figure 4E and Figure 4F Astigmatism curves of the optical system in Example 3 are shown for the operating wavelength range of 470-650nm and 920-960nm, respectively.

[0064] Figure 4G and Figure 4HThe magnification chromatic aberration curves of the optical system of Embodiment 3 are shown for the operating wavelength range of 470-650nm and the operating wavelength range of 920-960nm, respectively.

[0065] Figure 5 The simulation results of mechanical impact are shown when the optical system satisfies FOV=156.00, EP23 / (T23-CT3)=2.68, and EP23 / (T34-CT2)=2.13.

[0066] Figure 6 The simulation results of mechanical impact are shown when the optical system satisfies FOV=156.00, EP23 / (T23-CT3)=0.50, and EP23 / (T34-CT2)=5.61.

[0067] Figure 7 The simulation results of mechanical impact are shown when the optical system satisfies FOV=156.00, EP23 / (T23-CT3)=7.50, and EP23 / (T34-CT2)=9.31. Detailed Implementation

[0068] To better understand the invention, various aspects of the invention will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely illustrative of exemplary embodiments of the invention and are not intended to limit the scope of the invention 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.

[0069] It should be noted that in this specification, the terms "first," "second," "third," etc., are used only to distinguish one feature from another and do not imply any limitation on the features. Therefore, without departing from the teachings of the invention, the first lens discussed below may also be referred to as the second lens or the third lens, or the first lens may also be referred to as the first lens element.

[0070] In the accompanying drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustrative purposes only and are not strictly to scale.

[0071] In this paper, the paraxial region refers to the area near the optical axis. If the lens surface is convex and its location is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and its location is not defined, it means that the lens surface is concave at least in the paraxial region. The surface shape in the paraxial region can be determined by the sign of the R value (R refers to the radius of curvature of the paraxial region). In this paper, the surface of each lens closest to the subject is called the object-side surface, and the surface of each lens closest to the image plane is called the image-side surface. For the object-side surface, when the R value is positive, it is considered convex, and when the R value is negative, it is considered concave; for the image-side surface, when the R value is positive, it is considered concave, and when the R value is negative, it is considered convex.

[0072] In this invention, the object side refers to the side of the optical system facing the object being photographed (not shown in the figure), and the image side refers to the side of the optical system facing the imaging plane. Hereinafter, the object side of a lens refers to the surface of the lens facing the object being photographed (not shown in the figure), and the image side of a lens refers to the surface of the lens facing the imaging plane. The object side of a spacer element refers to the surface of the spacer element facing the object being photographed (not shown in the figure), and the image side of the spacer element refers to the surface of the spacer element facing the imaging plane.

[0073] In the structural schematic diagram shown in this invention, the left side is the object side and the right side is the image side.

[0074] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms (e.g., those defined in common dictionaries) shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formal sense, unless expressly so defined herein.

[0075] It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of this invention can be combined with each other. The following embodiments only illustrate several implementation methods of this invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of this invention. It should be pointed out that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of this invention, and these all fall within the protection scope of this invention.

[0076] like Figure 1A and Figure 1BAs shown, the optical system of an exemplary embodiment of the present invention includes a lens barrel, an imaging lens group, and multiple spacer elements. The imaging lens group includes seven lenses with optical power, which are sequentially arranged along the optical axis from the object side to the image side as follows: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens, wherein each lens is independent of the others, and each lens has an air gap along the optical axis.

[0077] The plurality of spacer elements include: a first spacer element disposed on the image side of a first lens and in at least partial contact with the image side of the first lens; a second spacer element disposed on the image side of a second lens and in at least partial contact with the image side of the second lens; a third spacer element disposed on the image side of a third lens and in at least partial contact with the image side of the third lens; a fourth spacer element disposed on the image side of a fourth lens and in at least partial contact with the image side of the fourth lens; a fifth spacer element disposed on the image side of a fifth lens and in at least partial contact with the image side of the fifth lens; a sixth spacer element disposed on the image side of a sixth lens and in at least partial contact with the image side of the sixth lens; and a seventh spacer element disposed on the image side of a seventh lens and in at least partial contact with the image side of the seventh lens.

[0078] The imaging lens group and multiple spacer elements are housed within the lens barrel, which includes an object-side end face, an image-side end face, an outer ring surface, and an inner ring surface. Along the optical axis of the optical system, the inner ring surface of the lens barrel is stepped.

[0079] In some embodiments of the present invention, the optical system may also include color filters and / or protective glass.

[0080] This invention provides an optical system including an imaging lens group and multiple spacer elements. The imaging lens group, along the optical axis from the object side to the image side, sequentially includes: a first lens with negative optical power, a second lens with negative optical power, a third lens with positive optical power, a fourth lens with positive optical power, a fifth lens with negative optical power, a sixth lens with positive optical power, and a seventh lens with negative optical power. This helps to balance system aberrations, meet the requirements of high resolution, and thus achieve better imaging results.

[0081] The optical system satisfies the following conditions: 144.00≤FOV≤164.60; 2.50≤EP23 / (T23-CT3)≤3.63; 4.80≤EP23 / (T34-CT2)≤6.22; where FOV is the maximum field of view of the optical system, T23 is the air gap between the second lens and the third lens on the optical axis, T34 is the air gap between the third lens and the fourth lens on the optical axis, CT2 is the center thickness of the second lens, CT3 is the center thickness of the third lens, and EP23 is the spacing distance between the second spacer element and the third spacer element along the optical axis.

[0082] In the optical system of this invention, the field of view of the optical system is large, the incident angle of the edge rays of the optical system is extremely large, and the optical system is extremely sensitive to the eccentricity and tilt of the lens. It is easy to cause serious astigmatism, coma and distortion due to small assembly errors. By controlling the optical system to meet the parameters 2.50≤EP23 / (T23-CT3)≤3.63 and 4.80≤EP23 / (T34-CT2)≤6.22, the center thickness of the lens and the air gap and spacing of the spacer elements on the optical axis can be controlled. This effectively improves the thickness and rigidity of the support surface between the third and fourth lenses to resist axial and radial impacts, reduce thermal distortion caused by air convection and temperature gradients, avoid excessively small lens peripheral spacing due to insufficient EP23, which increases the risk of edge collision during injection molding or assembly, and prevents insufficient heat dissipation space within the optical system, stress concentration due to thermal expansion and contraction of the lenses, and excessively thin edge thickness of the third lens, which increases the risk of mechanical impact breakage. This ensures that the second and third lenses do not shift under harsh environments (such as vibration and impact) and cause structural failure. As a result, the performance stability of the optical system in a wide temperature range is improved, thereby effectively improving the optical system's resistance to deformation, vibration, and temperature changes.

[0083] In addition, please refer to the following Figures 5 to 7 As shown, Figure 5 The simulation results of mechanical impact are shown when the optical system meets FOV=156.00, EP23 / (T23-CT3)=2.68, and EP23 / (T34-CT2)=2.13. The stress value of the second lens is 123.97MPa, which exceeds the lower limit of the range. The small center thickness CT2 of the second lens leads to a decrease in the center strength of the second lens. During the mechanical impact, the stress is concentrated at the center of the second lens, which increases the risk of cracking at the center of the second lens. Figure 6 The simulation results of mechanical impact are shown when the optical system meets FOV=156.00, EP23 / (T23-CT3)=0.50, and EP23 / (T34-CT2)=5.61. Within the range, the stress value of the second lens is 93.30, and the lens stress is safe during mechanical impact. Figure 7 The simulation results of mechanical impact are shown when the optical system satisfies FOV=156.00, EP23 / (T23-CT3)=7.50, and EP23 / (T34-CT2)=9.31. Exceeding the lower limit of the range, the increase in the spacing distance EP23 between the second spacer element and the third spacer element along the optical axis leads to a decrease in the edge thickness of the second lens. During the mechanical impact, the edge stress of the second lens increases, and the risk of edge cracking of the second lens increases.

[0084] In some embodiments of the present invention, the optical system satisfies: 5.91≤(CP6+CT7) / T67≤19.78; where CP6 is the maximum thickness of the sixth spacer element along the optical axis, CT7 is the center thickness of the seventh lens, and T67 is the air gap between the sixth lens and the seventh lens on the optical axis.

[0085] In the optical system of the present invention, the sum of the maximum thickness CP6 of the sixth spacer element along the optical axis and the center thickness CT7 of the seventh lens defines the air gap T67 between the sixth lens and the seventh lens on the optical axis. This constructs a stable radial boundary for the optical path in the air gap between the sixth lens and the seventh lens on the optical axis, which can prevent radial deviation of light rays and allow the seventh lens to perform aberration correction and divergence at the optimal incident angle, thus laying a stable foundation for image plane imaging.

[0086] In some embodiments of the present invention, the optical system satisfies: 7.17≤(D1s-D2s) / CT2≤9.28; 2.68≤DT11 / DT22≤3.04; where D1s is the outer diameter of the object side of the first spacer element, D2s is the outer diameter of the object side of the second spacer element, CT2 is the center thickness of the second lens, DT11 is the effective radius of the object side of the first lens, and DT22 is the effective radius of the image side of the second lens.

[0087] In the optical system of the present invention, by constraining the difference in outer diameter between the first and second spacer elements and the thickness of the center of the second lens, it is possible to ensure that there is a suitable gap for optical transmission and installation between the spacer elements on both sides of the second lens and the second lens. This avoids physical interference between the spacer elements and the edge of the second lens, and also prevents the optical path from shifting due to excessive gap. At the same time, by constraining the ratio of DT11 / DT22, the upper limit of the lens's light transmission capability can be limited, avoiding light cutoff and secondary stray light caused by mismatch in light transmission size in subsequent systems, and ensuring the continuity of light transmission of the entire optical system.

[0088] In some embodiments of the present invention, the optical system satisfies: 3.53≤R6 / d3s≤6.68; 7.07≤f3 / (CT3+CP3)≤8.76; where R6 is the radius of curvature of the image side of the third lens, d3s is the inner diameter of the object side of the third spacer element, f3 is the effective focal length of the third lens, CT3 is the center thickness of the third lens, and CP3 is the maximum thickness of the third spacer element along the optical axis.

[0089] In the optical system of this invention, by constraining the optical system to satisfy: 3.53≤R6 / d3s≤6.68 and 7.07≤f3 / (CT3+CP3)≤8.76, the optimal matching between the refractive power of the third lens and the structural thickness is achieved. Based on this, the effective light transmission boundary of the image side of the third lens is controlled to avoid interference problems in the optical path, and the light deflection effect of the image side of the third lens is optimized to avoid excessive / insufficient local refractive power of the lens due to an excessively large / small effective surface area, thereby reducing the deviation of light convergence or divergence and improving the clarity and sharpness of the image plane.

[0090] In some embodiments of the present invention, the optical system satisfies: -3.87 < d5s / (f5+f6) ≤ -1.77; 2.69 ≤ CT5 / (CP5+T56) ≤ 5.42; where d5s is the inner diameter of the object side of the fifth spacer element; f5 is the effective focal length of the fifth lens; f6 is the effective focal length of the sixth lens; CT5 is the center thickness of the fifth lens; CP5 is the maximum thickness of the fifth spacer element along the optical axis; and T56 is the air gap between the fifth lens and the sixth lens on the optical axis.

[0091] In the optical system of the present invention, by constraining the ratios of d5s / (f5+f6) and CT5 / (CP5+T56), the structural parameters of the fifth and sixth lenses are matched with the peripheral axial optical parameters and mechanical structural parameters. This allows the fifth lens to achieve the core functions of structural stiffness adaptation, assembly and operational reliability assurance in the lens optical path, ensuring that the fifth lens has sufficient structural thickness and good resistance to deformation and breakage.

[0092] In some embodiments of the present invention, for any two adjacent spacers among the plurality of spacers, the axial distance from the second spacer to the third spacer is the largest, and the optical system satisfies: 1.19≤T23 / (d2m-d3s)≤1.80; 19.16<(DT22-DT31) / CP3≤25.82; where T23 is the air gap between the second lens and the third lens on the optical axis, d2m is the inner diameter of the image-side surface of the second spacer, d3s is the inner diameter of the object-side surface of the third spacer, DT31 is the effective radius of the object-side surface of the third lens, DT22 is the effective radius of the image-side surface of the second lens, and CP3 is the maximum thickness of the third spacer along the optical axis.

[0093] By constraining the ratio of the maximum thickness of the third spacer element along the optical axis to the difference in the effective radius of the second and third lenses, and the ratio of the air gap T23 between the second and third lenses on the optical axis to the difference in the inner diameter of the third spacer element, the radial dimension difference between the two lenses is limited, and the positioning and support effect of the spacer element is optimized. On this basis, the axial optical gap is made to match the radial light-transmitting boundary height. At the same time, by positioning the area where "the axial distance from the second spacer element to the third spacer element is the largest", this area becomes the main buffer / main correction space of the lens axial optical path, providing sufficient axial space for the optical path coordination of the second and third lenses.

[0094] In some embodiments of the present invention, the optical system satisfies: -2.60≤f7 / d6s≤-1.25; -3.50≤R13 / d6m≤-2.08; where d6m is the inner diameter of the image side of the sixth spacer element, d6s is the inner diameter of the object side of the sixth spacer element, f7 is the effective focal length of the seventh lens, and R13 is the radius of curvature of the object side of the seventh lens.

[0095] In the optical system of the present invention, by constraining the ratio of f7 / d6s, the light divergence capability of the seventh lens can be matched with the light transmission range of the entrance port of the sixth spacer element. At the same time, the radius of curvature of the object side of the seventh lens and the inner diameter of the sixth spacer element on which the object side rests are constrained, taking into account both manufacturing feasibility and miniaturization, avoiding excessive optical load on the seventh lens, and preventing excessive internal stress caused by excessive local deflection of the seventh lens, which can easily lead to surface accuracy deviation during manufacturing, and surface deformation after assembly due to temperature or vibration, introducing additional aberrations.

[0096] In some embodiments of the present invention, the optical system satisfies: 2.63≤EP45 / (T45+T56)≤4.87; wherein, EP45 is the spacing distance between the fourth spacer element and the fifth spacer element along the optical axis, T45 is the air gap between the fourth lens and the fifth lens on the optical axis, and T56 is the air gap between the fifth lens and the sixth lens on the optical axis.

[0097] In the optical system of this invention, by constraining EP45 / (T45+T56), the axial transmission rhythm of the rear optical path in the optical system can be optimized, achieving a smooth transition of light from the preceding to the following stages. The middle and rear sections of the lens (the fourth to sixth lenses) are the intermediate nodes between the preceding optical path and the near-image plane optical path. The light transitions from the gradual convergence in the early stage to the precise convergence to the image plane in the later stage, requiring a smooth axial transmission rhythm. By constraining EP45 / (T45+T56), the optimal balance between the performance and practicality of the middle and rear optical path can be achieved, avoiding the increased processing difficulty or aberration correction failure caused by excessively narrow or wide intervals.

[0098] In some embodiments of the present invention, the optical system satisfies: 68.98≤(CP2+CP2b) / CP1≤85.77; -3.37≤f2 / (d2bm-d2bs)≤-2.32; where CP1 is the maximum thickness of the first spacer element along the optical axis, CP2 is the maximum thickness of the second spacer element along the optical axis, CP2b is the maximum thickness of the second auxiliary spacer element along the optical axis, f2 is the effective focal length of the second lens, d2bs is the inner diameter of the object side of the second auxiliary spacer element, and d2bm is the inner diameter of the image side of the second auxiliary spacer element.

[0099] In the optical system of the present invention, the second auxiliary spacer element is attached to the image side of the second spacer element and partially in contact with it. It is used to refine the axial positioning accuracy of the front optical path, supplement the structural stiffness, and increase the level of stray light suppression. The maximum thickness CP1 of the first spacer element along the optical axis serves as the front positioning reference and requires basic stiffness to support all subsequent front elements. By controlling the optical system to satisfy 68.98≤(CP2+CP2b) / CP1≤85.77 and -3.37≤f2 / (d2bm-d2bs)≤-2.32, deformation caused by the stiffness imbalance of the first spacer element can be avoided. At the same time, it adapts to the focusing and dispersion correction characteristics of the second lens and balances the optical path refraction angle of adjacent lenses.

[0100] In some embodiments of the present invention, the optical system satisfies: -2.40≤SAG51 / T45≤-0.73; 1.79≤CT5 / (d5s-d4m)≤4.29; where T45 is the air gap between the fourth lens and the fifth lens on the optical axis, SAG51 is the axial distance between the intersection of the object-side surface of the fifth lens and the optical axis and the vertex of the effective radius of the object-side surface of the fifth lens, CT5 is the center thickness of the fifth lens, d4m is the inner diameter of the image-side surface of the fourth spacer element, and d5s is the inner diameter of the object-side surface of the fifth spacer element.

[0101] In the optical system of the present invention, by controlling the optical system to satisfy the above two sets of conditions, the fifth lens and the surrounding optical path of the core of the rear section of the lens can be focused, so that the morphological characteristics and refractive characteristics of the object-side concave curved surface of the fifth lens are matched with the axial optical spacing between the fourth and fifth lenses, and the thickness of the fifth lens is adapted to the radial light transmission range. This avoids the fifth lens being too thin due to an excessively small ratio, resulting in a weak ability to control the deflection of off-axis light rays in a large radial range, leading to uneven deflection of edge light rays and blurred edges of the field of view.

[0102] In some embodiments of the present invention, the optical system satisfies: 1.40≤(D5m-d5m) / CT6≤1.99; where D5m is the outer diameter of the image-side surface of the fifth spacer element, d5m is the inner diameter of the image-side surface of the fifth spacer element, and CT6 is the center thickness of the sixth lens.

[0103] In the optical system of the present invention, the radial structure of the fifth spacer element and the sixth lens is constrained by the ratio of the difference between the outer diameter and inner diameter of the image side of the fifth spacer element (D5m-d5m) and the center thickness (CT6) of the sixth lens. This allows the fifth spacer element and the sixth lens to form a radially adapted, stray light-suppressing, and stably and reliably assembled synergistic cooperation, and to construct a fitted radial annular light-shielding step, which effectively suppresses stray light in the rear optical path.

[0104] In some embodiments of the present invention, the optical system satisfies: 14.70≤CT6 / T67≤41.67; 9.31≤EP56 / T67≤23.46; wherein CT6 is the center thickness of the sixth lens, T67 is the air gap between the sixth lens and the seventh lens on the optical axis, and EP56 is the spacing distance between the fifth spacer element and the sixth spacer element along the optical axis.

[0105] In the optical system of this invention, by controlling the optical system to meet the design of 14.70≤CT6 / T67≤41.67 and 9.31≤EP56 / T67≤23.46, the precise matching of the rear mechanical positioning reference and the core optical spacing can be ensured. This achieves the limitation of the center thickness of the sixth lens and the center spacing between the sixth and seventh lenses, avoiding insufficient beam-gathering ability of the sixth lens due to an excessively small CT6 / T67 ratio, which would cause excessive divergence of light in the air gap between the excessively long sixth and seventh lenses on the optical axis, resulting in field curvature and aggravated distortion. At the same time, it avoids excessive divergence correction of the negative lens and the introduction of additional astigmatism due to an excessively large CT6 / T67 ratio, which would cause light to enter the seventh lens without forming a stable propagation path in the air gap between the excessively short sixth and seventh lenses on the optical axis.

[0106] In some embodiments of the present invention, the plurality of spacers includes: a second auxiliary spacer, disposed on the image side of the second spacer and at least partially in contact with the image side of the second spacer; a third auxiliary spacer, disposed on the image side of the third spacer and at least partially in contact with the image side of the third spacer; the optical system satisfies: 1.36≤(CP2b+CP3b) / CT3≤2.14; wherein, CT3 is the center thickness of the third lens, CP2b is the maximum thickness of the second auxiliary spacer along the optical axis, and CP3b is the maximum thickness of the third auxiliary spacer along the optical axis.

[0107] In the optical system of the present invention, by controlling the optical system to satisfy the above-mentioned relationship, the core optical path (third lens and peripheral auxiliary spacer elements) transitioning from the front to the middle section of the lens can be focused. By superimposing the thickness of the two auxiliary spacer elements, the sum of the auxiliary spacer thicknesses is matched with the ratio of the center thickness of the third lens, thereby strengthening the overall structural rigidity of the front and middle section optical path. This effectively resists radial extrusion pressure during assembly and vibration impact during operation, and avoids axial micro-movement or radial eccentricity of the front and middle section elements.

[0108] In some embodiments of the invention, the plurality of spacers further include auxiliary spacers positioned on the object side of the first lens and in at least partial contact with the first lens. The auxiliary spacers provide additional fixation and support for the lens, a design that helps prevent displacement or loosening of the lens during assembly or use, thereby ensuring the stability and reliability of the entire optical system.

[0109] In some embodiments of the present invention, the optical system satisfies: 13.27≤CT6 / (T67+CP6)≤31.25; -3.76≤R14 / R13≤-0.32; where CT6 is the center thickness of the sixth lens, CP6 is the maximum thickness of the sixth spacer element along the optical axis, T67 is the air gap between the sixth lens and the seventh lens on the optical axis, R13 is the radius of curvature of the object side of the seventh lens, and R14 is the radius of curvature of the image side of the seventh lens.

[0110] In the optical system of this invention, the constraint optical system satisfies the ultra-high magnification design of 13.27≤CT6 / (T67+CP6)≤31.25 and -3.76≤R14 / R13≤-0.32. This design limits the stability of the near-image plane structure in the rear section, ensuring the ultra-high structural stiffness and surface stability of the sixth and seventh lenses. It can withstand extreme stress in the rear working conditions. When the sixth and seventh lenses have ultra-high structural stiffness, they can effectively resist radial extrusion during assembly, vibration and impact during operation (such as high-frequency vibration in vehicle and security scenarios), and thermal expansion and contraction under high and low temperature conditions (-40℃~85℃), preventing micro-deformation of the optical surface of the sixth and seventh lenses and deviation of the optical center from the optical axis.

[0111] In some embodiments of the present invention, the operating wavelength range of the optical system may be 470nm ≤ λ ≤ 960nm. By limiting the operating wavelength range of the optical imaging system, the operating wavelengths of the lens and the image sensor are matched, maintaining the synchronization of the transmitting and receiving devices and obtaining high-precision detection distance.

[0112] In some embodiments of the present invention, the first lens and the sixth lens are made of glass. By controlling the first lens located on the light-incident side of the optical system and the sixth lens located on the light-outcident side of the optical system to be glass lenses, since glass lenses have a lower temperature drift coefficient and stronger thermal stability compared to plastic lenses, it can ensure that the first lens and the sixth lens of the optical system are not easily deformed under high and low temperature conditions, and can stably maintain the aberration correction capability of the system.

[0113] The optical system according to the above embodiments of the present invention can employ multiple lenses, such as the seven lenses mentioned above. By rationally allocating the optical power, surface shape, and arrangement of the spacers of each lens, the range of each lens-tube engagement is made more uniform, enhancing the light-gathering ability and improving the imaging quality of the optical system.

[0114] In some embodiments of the present invention, the lens material in the optical system provided by the present invention can be glass or plastic. When the lens material is plastic, production costs can be effectively reduced. Alternatively, when the lens material is glass, the low dispersion characteristic of glass itself can effectively correct the geometric chromatic aberration of the optical system.

[0115] In some embodiments of the present invention, the first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, and seventh lens can be spherical lenses or aspherical lenses. Compared with spherical structures, aspherical structures can effectively reduce the aberrations of the optical system, thereby reducing the number of lenses and the size of the lenses, and better achieving lens miniaturization. More specifically, the second lens, third lens, fourth lens, sixth lens, and seventh lens of the present invention can all be aspherical lenses.

[0116] When aspherical lenses are used, the surface shape of each aspherical lens in the optical system can be defined using, but is not limited to, the following aspherical formulas:

[0117]

[0118] In the above formula, The height perpendicular to the optical axis is along the optical axis. The axial distance from the vertex to the surface at the location; This represents the curvature at the vertex of the aspherical surface. The conic coefficient; , , , , , , ... represent aspherical coefficients of order 4, 6, 8, 10, 12, 14, and 16 respectively.

[0119] The present invention will be further described below with reference to several embodiments. In each embodiment, the thickness, radius of curvature, and material selection of each lens in the optical system are 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 to the following embodiments. Any changes, substitutions, combinations, or simplifications made without departing from the innovative points of the present invention should be considered as equivalent substitutions and are included within the protection scope of the present invention. In addition, it should be noted that in the following Embodiment 1, there are three examples of optical systems 1001, 1002, and 1003; in Embodiment 2, there are three examples of optical systems 2001, 2002, and 2003; and in Embodiment 3, there are three examples of optical systems 3001, 3002, and 3003. The structures of the optical systems in different examples are different, but the optical parameters of the optical systems in the three examples in the same embodiment are the same, that is, the radius of curvature, center thickness, and other parameters of the first to seventh lenses, as well as the spacing distance and higher-order coefficients between the lenses are the same.

[0120] Example 1

[0121] The following is for reference Figures 2A to 2H Optical systems 1001, 1002, and 1003 according to Embodiment 1 of the present invention are described. Figure 2A , Figure 2B and Figure 2C Schematic diagrams of optical systems 1001, 1002, and 1003 according to Embodiment 1 of the present invention are shown respectively.

[0122] like Figure 2A , Figure 2B and Figure 2C As shown, the structural schematic diagrams of optical systems 1001, 1002, and 1003 all include a lens barrel P0, an imaging lens group, and multiple spacer elements P1 to P7.

[0123] In Embodiment 1, the schematic diagrams of optical systems 1001, 1002, and 1003 employ the same imaging lens group. The imaging lens group, from the object side to the image side, sequentially includes: a first lens E1 with negative optical power, a second lens E2 with negative optical power, a third lens E3 with positive optical power, a fourth lens E4 with positive optical power, a fifth lens E5 with negative optical power, a sixth lens E6 with positive optical power, and a seventh lens E7 with negative optical power. The first lens... Lens E1 has a convex object-side surface S1 and a concave image-side surface S2; the second lens E2 has concave object-side surface S3 and image-side surface S4; the third lens E3 has a convex object-side surface S5 and a concave image-side surface S6; the fourth lens E4 has convex object-side surface S7 and image-side surface S8; the fifth lens E5 has concave object-side surface S9 and image-side surface S10; the sixth lens E6 has convex object-side surface S11 and image-side surface S12; and the seventh lens E7 has concave object-side surface S13 and image-side surface S14. An aperture stop is positioned between the third lens E3 and the fourth lens E4. Light from the object passes sequentially through surfaces S1 to S16 and is finally imaged onto the imaging surface S17. Surfaces S15 and S16 (not shown in the figure) can be the object-side and image-side surfaces of filters or protective glass, OBJ (not shown in the figure) is the object surface, STO (not shown in the figure) is the aperture stop, and surface S17 (not shown in the figure) is the imaging surface.

[0124] Table 1 lists the relevant parameters of each lens in the optical system of this embodiment, including: surface type, radius of curvature, thickness, refractive index of the material, Abbe number and conic coefficient, wherein the units of radius of curvature and thickness are millimeters (mm).

[0125]

[0126] Table 1

[0127] Table 2 lists the aspherical coefficients of each aspherical lens in the optical system of this embodiment, including: A4, A6, A8, A... 10 A 12 A 14 A 16 A 18 A 20 .

[0128]

[0129] Table 2

[0130] like Figure 2A , 2BAs shown in Figure 2C, optical systems 1001, 1002, and 1003 all include an auxiliary spacer element Pa, a first spacer element P1, a second spacer element P2, a second auxiliary spacer element P2b, a third spacer element P3, a third auxiliary spacer element P3b, a fourth spacer element P4, a fifth spacer element P5, and a sixth spacer element P6. The auxiliary spacer element Pa is disposed on the object side of the first lens E1, and its image side is at least partially in contact with the object side of the first lens E1.

[0131] Figure 2D The on-axis chromatic aberration curve of the optical system of Embodiment 1 is shown, which represents the deviation of the focal point of light of different wavelengths after passing through the lens. The wavelengths of the light are 470nm, 510nm, 555nm, 610nm, 650nm, 920mm, 960mm, and 940mm, respectively. The horizontal axis of the curve represents the offset in mm, and the vertical axis represents the normalized aperture. Figure 2E and Figure 2F The astigmatism curves of the optical system of Embodiment 1 are shown in the operating wavelength range of 470-650nm and 920-960nm. They represent the axial position offset of the meridional and sagittal image planes of light rays at different field of view after passing through the optical system. The vertical axis represents the field of view in °, and the horizontal axis represents the position offset of the actual image plane in mm. Figure 2G and Figure 2H The magnification and chromatic aberration curves of the optical system of Embodiment 1 are shown for the operating wavelength ranges of 470-650nm and 920-960nm. These curves indicate that different wavelengths of light, after passing through the optical system, result in inconsistent imaging magnification and a positional shift of the off-axis image point in the direction perpendicular to the optical axis. The horizontal axis represents the vertical chromatic aberration in μm, and the vertical axis represents the normalized field of view. According to... Figures 2D to 2H As can be seen, the optical system given in Example 1 can achieve good imaging quality.

[0132] Example 2

[0133] The following is for reference Figures 3A to 3H Optical systems 2001, 2002, and 2003 according to Embodiment 2 of the present invention are described. Figure 3A , Figure 3B and Figure 3C Schematic diagrams of optical systems 2001, 2002 and 2003 according to Embodiment 2 of the present invention are shown respectively.

[0134] like Figure 3A , Figure 3B and Figure 3CAs shown, the structural schematic diagrams of optical systems 2001, 2002, and 2003 all include a lens barrel P0, an imaging lens group, and multiple spacer elements P1 to P7.

[0135] In Embodiment 2, the schematic diagrams of optical systems 2001, 2002, and 2003 employ the same imaging lens group. The imaging lens group, from the object side to the image side, sequentially includes: a first lens E1 with negative optical power, a second lens E2 with negative optical power, a third lens E3 with positive optical power, a fourth lens E4 with positive optical power, a fifth lens E5 with negative optical power, a sixth lens E6 with positive optical power, and a seventh lens E7 with negative optical power. The first lens... The object-side surface S1 of lens E1 is convex, and its image-side surface S2 is concave; the object-side surface S3 and image-side surface S4 of the second lens E2 are both concave; the object-side surface S5 of the third lens E3 is convex, and its image-side surface S6 is concave; the object-side surface S7 and image-side surface S8 of the fourth lens E4 are both convex; the object-side surface S9 of the fifth lens E5 is convex, and its image-side surface S10 is concave; the object-side surface S11 and image-side surface S12 of the sixth lens E6 are both convex; and the object-side surface S13 and image-side surface S14 of the seventh lens E7 are both concave. An aperture stop is positioned between the third lens E3 and the fourth lens E4. Light from the object passes sequentially through surfaces S1 to S16 and is finally imaged onto the imaging surface S17. Surfaces S15 and S16 (not shown in the figure) can be the object-side and image-side surfaces of filters or protective glass, OBJ (not shown in the figure) is the object surface, STO (not shown in the figure) is the aperture stop, and surface S17 (not shown in the figure) is the imaging surface.

[0136] Table 3 lists the relevant parameters of each lens in the optical system of this embodiment, including: surface type, radius of curvature, thickness, refractive index of the material, Abbe number and conic coefficient, wherein the units of radius of curvature and thickness are millimeters (mm).

[0137]

[0138] Table 3

[0139] Table 4 lists the aspherical coefficients of each aspherical lens in the optical system of this embodiment, including: A4, A6, A8, A... 10 A 12 A 14 A 16 A 18 A 20 .

[0140]

[0141] Table 4

[0142] like Figure 3A ,2B As shown in Figure 2C, optical systems 2001, 2002, and 2003 all include auxiliary spacer element Pa, first spacer element P1, second spacer element P2, second auxiliary spacer element P2b, third spacer element P3, third auxiliary spacer element P3b, fourth spacer element P4, fifth spacer element P5, and sixth spacer element P6. The positions of each spacer element have been described above and will not be repeated here.

[0143] Figure 3D The on-axis chromatic aberration curve of the optical system of Embodiment 2 is shown, which represents the deviation of the focal point of light of different wavelengths after passing through the lens. The wavelengths of the light are 435nm, 470nm, 510nm, 555nm, 610nm, 650nm, 920mm, 960mm, and 940mm, respectively. The horizontal axis of the curve represents the offset in mm, and the vertical axis represents the normalized aperture. Figure 3E and Figure 3F The astigmatism curves of the optical system of Embodiment 2 are shown in the operating wavelength range of 470-650nm and 920-960nm. They represent the axial position offset of the meridional and sagittal image planes of light rays at different field of view after passing through the optical system. The vertical axis represents the field of view in °, and the horizontal axis represents the actual position offset of the image plane in mm. Figure 3G and Figure 3H The magnification and chromatic aberration curves of the optical system of Embodiment 2 are shown for the operating wavelength ranges of 470-650nm and 920-960nm. These curves indicate that different wavelengths of light, after passing through the optical system, result in inconsistent imaging magnification and a positional shift of the off-axis image point in the direction perpendicular to the optical axis. The horizontal axis represents the vertical chromatic aberration in μm, and the vertical axis represents the normalized field of view. According to... Figures 3D to 3H It can be seen that the optical system given in Example 2 can achieve good imaging quality.

[0144] Example 3

[0145] The following is for reference Figures 4A to 4H The optical systems 3001, 3002, and 3003 according to Embodiment 3 of the present invention are described. Figure 4A , Figure 4B and Figure 4C Schematic diagrams of optical systems 3001, 3002 and 3003 according to Embodiment 3 of the present invention are shown respectively.

[0146] like Figure 4A , Figure 4B and Figure 4CAs shown, the structural schematic diagrams of optical systems 3001, 3002, and 3003 all include a lens barrel P0, an imaging lens group, and multiple spacer elements P1 to P7.

[0147] In Embodiment 3, the structural schematic diagrams of optical systems 3001, 3002, and 3003 employ the same imaging lens group. The imaging lens group, from the object side to the image side, sequentially includes: a first lens E1 with negative optical power, a second lens E2 with negative optical power, a third lens E3 with positive optical power, a fourth lens E4 with positive optical power, a fifth lens E5 with negative optical power, a sixth lens E6 with positive optical power, and a seventh lens E7 with negative optical power. The first lens... Lens E1 has a convex object-side surface S1 and a concave image-side surface S2; the second lens E2 has concave object-side surface S3 and image-side surface S4; the third lens E3 has a convex object-side surface S5 and a concave image-side surface S6; the fourth lens E4 has convex object-side surface S7 and image-side surface S8; the fifth lens E5 has concave object-side surface S9 and image-side surface S10; the sixth lens E6 has convex object-side surface S11 and image-side surface S12; and the seventh lens E7 has concave object-side surface S13 and image-side surface S14. An aperture stop is positioned between the third lens E3 and the fourth lens E4. Light from the object passes sequentially through surfaces S1 to S16 and is finally imaged onto the imaging surface S17. Surfaces S15 and S16 (not shown in the figure) can be the object-side and image-side surfaces of filters or protective glass, OBJ (not shown in the figure) is the object surface, STO (not shown in the figure) is the aperture stop, and surface S17 (not shown in the figure) is the imaging surface.

[0148] Table 5 lists the relevant parameters of each lens in the optical system of this embodiment, including: surface type, radius of curvature, thickness, refractive index of the material, Abbe number and conic coefficient, wherein the units of radius of curvature and thickness are millimeters (mm).

[0149]

[0150] Table 5

[0151] Table 6 lists the aspherical coefficients of each aspherical lens in the optical system of this embodiment, including: A4, A6, A8, A... 10 A 12 A 14 A 16 A 18 A 20 .

[0152]

[0153] Table 6

[0154] like Figure 4A , Figure 4B and Figure 4C As shown, optical systems 3001, 3002, and 3003 all include auxiliary spacer element Pa, first spacer element P1, second spacer element P2, second auxiliary spacer element P2b, third spacer element P3, third auxiliary spacer element P3b, fourth spacer element P4, fifth spacer element P5, and sixth spacer element P6. The positions of each spacer element have been described above and will not be repeated here.

[0155] Figure 4D The on-axis chromatic aberration curve of the optical system of Embodiment 3 is shown, which represents the deviation of the focal point of light of different wavelengths after passing through the lens. The wavelengths of the light are 435nm, 470nm, 510nm, 555nm, 610nm, 650nm, 920mm, 960mm, and 940mm, respectively. The horizontal axis of the curve represents the offset in mm, and the vertical axis represents the normalized aperture. Figure 4E and Figure 4F The astigmatism curves of the optical system of Embodiment 3 are shown in the operating wavelength range of 470-650nm and 920-960nm. They represent the axial position offset of the meridional and sagittal image planes of light rays at different field of view after passing through the optical system. The vertical axis represents the field of view in °, and the horizontal axis represents the position offset of the actual image plane in mm. Figure 4G and Figure 4H The magnification chromatic aberration curves of the optical system of Embodiment 3 are shown for the operating wavelength ranges of 470-650nm and 920-960nm. These curves indicate that different wavelengths of light, after passing through the optical system, result in inconsistent imaging magnification and a positional shift of the off-axis image point in the direction perpendicular to the optical axis. The horizontal axis represents the vertical chromatic light image height shift in the direction perpendicular to the optical axis, measured in µm, and the vertical axis represents the normalized field of view. According to... Figures 4D to 4H As can be seen, the optical system given in Example 3 can achieve good imaging quality.

[0156] In summary, the optical parameters of the optical systems 1001, 1002, 1003, 2001, 2002, 2003, 3001, 3002 and 3003 of Embodiments 1 to 3 are shown in Table 7 below.

[0157]

[0158] Table 7

[0159] The basic parameters of the spacer elements and lens barrels of the optical systems 1001, 1002, 1003, 2001, 2002, 2003, 3001, 3002 and 3003 of Examples 1 to 3 are shown in Table 8 below, where the unit of each parameter is mm.

[0160]

[0161] Table 8

[0162] The optical systems 1001, 1002, 1003, 2001, 2002, 2003, 3001, 3002, and 3003 of Examples 1 to 3 satisfy the relationships shown in Table 9.

[0163]

[0164] Table 9

[0165] The above description is merely a preferred embodiment of the present invention and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention is not limited to the specific combination of the above-described technical features, but also includes other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions disclosed in this invention.

Claims

1. An optical system comprising a lens barrel having a receiving space, characterized in that, The containment space is equipped with an imaging lens group and multiple spacer elements. The imaging lens group includes, in sequence along the optical axis from the object side to the image side: a first lens with negative optical power, a second lens with negative optical power, a third lens with positive optical power, a fourth lens with positive optical power, a fifth lens with negative optical power, a sixth lens with positive optical power, and a seventh lens with negative optical power, for a total of seven lenses with optical power. The plurality of spacers include: a second spacer element disposed on the image side of the second lens and in at least partial contact with the image side surface of the second lens; and a third spacer element disposed on the image side of the third lens and in at least partial contact with the image side surface of the third lens. The optical system satisfies: 144.00°≤FOV≤164.60°; 2.50≤EP23 / (T23-CT3)≤3.63; 4.80≤EP23 / (T34-CT2)≤6.22; Wherein, FOV is the maximum field of view of the optical system, T23 is the air gap between the second lens and the third lens on the optical axis, T34 is the air gap between the third lens and the fourth lens on the optical axis, CT2 is the center thickness of the second lens, CT3 is the center thickness of the third lens, and EP23 is the spacing distance between the second spacer element and the third spacer element along the optical axis.

2. The optical system according to claim 1, characterized in that, The plurality of spacer elements includes: a sixth spacer element, which is disposed on the image side of the sixth lens and at least partially contacts the image side of the sixth lens; The optical system satisfies: 5.91≤(CP6+CT7) / T67≤19.78; Wherein, CP6 is the maximum thickness of the sixth spacer element along the optical axis, CT7 is the center thickness of the seventh lens, and T67 is the air gap between the sixth and seventh lenses on the optical axis.

3. The optical system according to claim 1, characterized in that, The plurality of spacers includes: a first spacer element, which is disposed on the image side of the first lens and at least partially contacts the image side of the first lens; The optical system satisfies: 7.17≤(D1s-D2s) / CT2≤9.28; 2.68≤DT11 / DT22≤3.04; Wherein, D1s is the outer diameter of the object side of the first spacer element, D2s is the outer diameter of the object side of the second spacer element, CT2 is the center thickness of the second lens, DT11 is the effective radius of the object side of the first lens, and DT22 is the effective radius of the image side of the second lens.

4. The optical system according to claim 1, characterized in that, The optical system satisfies: 3.53≤R6 / d3s≤6.68; 7.07≤f3 / (CT3+CP3)≤8.76; Wherein, R6 is the radius of curvature of the image side of the third lens, d3s is the inner diameter of the object side of the third spacer element, f3 is the effective focal length of the third lens, CT3 is the center thickness of the third lens, and CP3 is the maximum thickness of the third spacer element along the optical axis.

5. The optical system according to claim 1, characterized in that, The plurality of spacer elements includes: a fifth spacer element, which is disposed on the image side of the fifth lens and at least partially contacts the image side of the fifth lens; The optical system satisfies: -3.87 < d5s / (f5+f6) ≤ -1.77; 2.69 ≤ CT5 / (CP5+T56) ≤ 5.42; Wherein, d5s is the inner diameter of the object side of the fifth spacer element; f5 is the effective focal length of the fifth lens; f6 is the effective focal length of the sixth lens; CT5 is the center thickness of the fifth lens; CP5 is the maximum thickness of the fifth spacer element along the optical axis; and T56 is the air gap between the fifth lens and the sixth lens on the optical axis.

6. The optical system according to claim 1, characterized in that, For any two adjacent spacers among the plurality of spacers, the on-axis distance from the second spacer to the third spacer is the largest, and the optical system satisfies: 1.19≤T23 / (d2m-d3s)≤1.80; 19.16<(DT22-DT31) / CP3≤25.82; Wherein, T23 is the air gap between the second lens and the third lens on the optical axis, d2m is the inner diameter of the image side of the second spacer element, d3s is the inner diameter of the object side of the third spacer element, DT31 is the effective radius of the object side of the third lens, DT22 is the effective radius of the image side of the second lens, and CP3 is the maximum thickness of the third spacer element along the optical axis.

7. The optical system according to claim 1, characterized in that, The plurality of spacer elements includes: a sixth spacer element, which is disposed on the image side of the sixth lens and at least partially contacts the image side of the sixth lens; The optical system satisfies: -2.60≤f7 / d6s≤-1.25; -3.50≤R13 / d6m≤-2.08; Wherein, d6m is the inner diameter of the image side of the sixth spacer element, d6s is the inner diameter of the object side of the sixth spacer element, f7 is the effective focal length of the seventh lens, and R13 is the radius of curvature of the object side of the seventh lens.

8. The optical system according to claim 1, characterized in that, The plurality of spacers includes: a fourth spacer element disposed on the image side of the fourth lens and in at least partial contact with the image side surface of the fourth lens; and a fifth spacer element disposed on the image side of the fifth lens and in at least partial contact with the image side surface of the fifth lens. The optical system satisfies: 2.63≤EP45 / (T45+T56)≤4.87; Wherein, EP45 is the spacing distance between the fourth spacer element and the fifth spacer element along the optical axis, T45 is the air gap between the fourth lens and the fifth lens on the optical axis, and T56 is the air gap between the fifth lens and the sixth lens on the optical axis.

9. The optical system according to claim 1, characterized in that, The plurality of spacers include: a first spacer element disposed on the image side of the first lens and in at least partial contact with the image side of the first lens; and a second auxiliary spacer element disposed on the image side of the second spacer element and in at least partial contact with the image side of the second spacer element. The optical system satisfies: 68.98≤(CP2+CP2b) / CP1≤85.77; -3.37≤f2 / (d2bm-d2bs)≤-2.32; Wherein, CP1 is the maximum thickness of the first spacer element along the optical axis, CP2 is the maximum thickness of the second spacer element along the optical axis, CP2b is the maximum thickness of the second auxiliary spacer element along the optical axis, f2 is the effective focal length of the second lens, d2bs is the inner diameter of the object side of the second auxiliary spacer element, and d2bm is the inner diameter of the image side of the second auxiliary spacer element.

10. The optical system according to claim 1, characterized in that, The plurality of spacers includes: a fourth spacer element disposed on the image side of the fourth lens and in at least partial contact with the image side surface of the fourth lens; and a fifth spacer element disposed on the image side of the fifth lens and in at least partial contact with the image side surface of the fifth lens. The optical system satisfies: -2.40≤SAG51 / T45≤-0.73; 1.79≤CT5 / (d5s-d4m)≤4.29; Wherein, T45 is the air gap between the fourth lens and the fifth lens on the optical axis, SAG51 is the axial distance between the intersection of the object side surface of the fifth lens and the optical axis and the vertex of the effective radius of the object side surface of the fifth lens, CT5 is the center thickness of the fifth lens, d4m is the inner diameter of the image side surface of the fourth spacer element, and d5s is the inner diameter of the object side surface of the fifth spacer element.

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