Optical system

Abstract

The invention relates to an optical system, which comprises a lens barrel, an optical imaging lens group and a plurality of spacing elements, and is characterized in that the optical imaging lens group sequentially comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens from an object side to an image side along an optical axis; the plurality of spacing elements comprise a second spacing element and a third spacing element; the second spacing element is positioned between the second lens and the third lens and is in contact with the image side surface of the second lens; the third spacing element is positioned between the third lens and the fourth lens and is in contact with the image side surface of the third lens; the optical system satisfies the following conditions:-5.88 < = f34 / R8 < =-3.79; -3.25 < = R6 / (D3s-d3s) < =-1.11; 4.91 < = f3 * N3 / EP23 < = 7.77. According to the optical system, aberration correction is achieved, meanwhile, gap sensitivity of the third lens and the fourth lens is reduced, the optical MTF is guaranteed, and the imaging quality is improved.

Description

Technical Field

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

[0002] With the booming development of the consumer electronics market in recent years, especially the rapid popularization of emerging smart devices such as VR / AR / MR, consumers have placed increasingly higher demands on the immersive experience and visual effects of these devices. As a core component of these devices, the performance of the optical system, such as resolution, field of view, distortion control, and color reproduction capabilities, directly determines the user's final experience. In order to meet the market's demands for high definition, wide field of view, thinness, and low cost, the industry is constantly exploring the design of optical lenses, striving to achieve optimal imaging quality within limited space.

[0003] In traditional optical design, methods such as increasing the number of lenses, introducing aspherical lenses, or using special materials are commonly employed to correct various aberrations, including spherical aberration, coma, and astigmatism. Among these, to achieve effective control of light and aberration correction within a compact structure, lenses with a large curvature (i.e., a small radius of curvature) are often required. These high-curvature lenses can deflect light more effectively, thereby improving image quality while reducing the number of lenses and the overall system length.

[0004] However, the widespread use of high-curvature lenses also presents significant challenges to the production and assembly of optical systems. First, from a manufacturing perspective, high-curvature aspherical lenses require extremely high processing precision; even minute surface shape errors can lead to a significant deterioration in the final image quality. Second, during assembly, the high curvature of the lens surface makes the relative positions between lenses (such as center offset, tilt, and air gap) extremely sensitive. Even minor assembly errors can severely degrade system performance, particularly causing irreversible negative impacts on the modulation transfer function (MTF, a key indicator of lens resolving power). This extreme sensitivity to tolerances not only significantly increases the difficulty of production and assembly but also leads to lower product yields and higher costs.

[0005] It is evident that existing technologies still face the challenge of balancing aberration correction with assembly reliability. Summary of the Invention

[0006] To address the problems existing in the prior art, the present invention aims to provide an optical system that achieves high resolution, optimized aberrations, and stable assembly by optimizing the design of lenses and spacers.

[0007] To achieve the above-mentioned objectives, the present invention provides an optical system comprising a lens barrel, an optical imaging lens group, and multiple spacer elements.

[0008] The optical imaging lens group consists of, along the optical axis from the object side to the image side, a first lens with negative optical power, a second lens with positive optical power, a third lens with positive optical power, a fourth lens with negative optical power, and a fifth lens with positive optical power.

[0009] The plurality of spacers include a second spacer located between the second lens and the third lens and in contact with the image-side surface of the second lens, and a third spacer located between the third lens and the fourth lens and in contact with the image-side surface of the third lens;

[0010] The optical system satisfies:

[0011] -5.88≤f34 / R8≤-3.79;

[0012] -3.25≤R6 / (D3s-d3s)≤-1.11;

[0013] 4.91≤f3*N3 / EP23≤7.77;

[0014] Wherein, f34 is the combined focal length of the third lens and the fourth lens, R8 is the radius of curvature of the image-side surface of the fourth lens, R6 is the radius of curvature of the image-side surface of the third lens, d3s is the inner diameter of the object-side surface of the third spacer element, D3s is the outer diameter of the object-side surface of the third spacer element, f3 is the effective focal length of the third lens, N3 is the refractive index of the third lens, and EP23 is the spacing distance between the second spacer element and the third spacer element along the optical axis.

[0015] According to one technical solution of the present invention, the spacer element further includes a fourth spacer element located between the fourth lens and the fifth lens and in contact with the image side of the fourth lens;

[0016] The optical system satisfies: -1.89≤SAG41 / CT4≤-1.62;

[0017] -2.63≤EP34 / SAG42≤-2.11;

[0018] Wherein, CT4 is the center thickness of the fourth lens, SAG41 is the axial displacement from the intersection of the object-side surface of the fourth lens and the optical axis to the vertex of the effective radius of the optical region of the object-side surface of the fourth lens, SAG42 is the axial displacement from the intersection of the image-side surface of the fourth lens and the optical axis to the vertex of the effective radius of the optical region of the image-side surface of the fourth lens, and EP34 is the spacing distance between the third spacer element and the fourth spacer element along the optical axis.

[0019] According to one technical solution of the present invention, the optical system satisfies:

[0020] 2.32≤CT5 / T45≤2.61;

[0021] 1.56≤(D4m-d4m) / R9≤2.28;

[0022] Wherein, CT5 is the center thickness of the fifth lens, T45 is the air gap between the fourth and fifth lenses on the optical axis, R9 is the radius of curvature of the object side of the fifth lens, d4m is the inner diameter of the image side of the fourth spacer element, and D4m is the outer diameter of the image side of the fourth spacer element.

[0023] According to one technical solution of the present invention, the spacer element further includes a first spacer element located between the first lens and the second lens and in contact with the image side of the first lens;

[0024] The optical system satisfies:

[0025] -32.75≤f1 / EP01≤-15.16;

[0026] Wherein, EP01 is the distance between the object-side end face of the lens barrel and the first spacer element along the optical axis, and f1 is the effective focal length of the first lens.

[0027] According to one technical solution of the present invention, the optical system satisfies:

[0028] 0.68≤R1 / (D1s-d1s)≤1.63;

[0029] Wherein, R1 is the radius of curvature of the object side surface of the first lens, D1s is the outer diameter of the object side surface of the first spacer element, and d1s is the inner diameter of the object side surface of the first spacer element.

[0030] According to one technical solution of the present invention, the optical system satisfies:

[0031] 2.92≤f2 / (d2s-d1m)≤10.87;

[0032] Where f2 is the effective focal length of the second lens, d1m is the inner diameter of the image side of the first spacer element, and d2s is the inner diameter of the object side of the second spacer element.

[0033] According to one technical solution of the present invention, the optical system satisfies:

[0034] 2.83≤R3 / d1m≤4.16;

[0035] Wherein, R3 is the radius of curvature of the object side of the second lens, and d1m is the inner diameter of the image side of the first spacer element.

[0036] According to one technical solution of the present invention, the optical system satisfies:

[0037] 1.1≤(T12+T23) / EP12≤1.98;

[0038] Wherein, T12 is the air gap between the first lens and the second lens on the optical axis, T23 is the air gap between the second lens and the third lens on the optical axis, and EP12 is the spacing distance between the first spacer element and the second spacer element along the optical axis.

[0039] According to one technical solution of the present invention, the optical system satisfies:

[0040] 1.24≤D1s / (R2*N1)≤1.75;

[0041] Wherein, D1s is the outer diameter of the object side of the first spacer element, R2 is the radius of curvature of the image side of the first lens, and N1 is the refractive index of the first lens.

[0042] According to one technical solution of the present invention, the optical system satisfies:

[0043] 4.61≤(SAG12+CT2) / EP12≤7.51;

[0044] Wherein, SAG12 is the axial displacement from the intersection of the image-side surface of the first lens and the optical axis to the vertex of the effective radius of the optical region of the image-side surface of the first lens, CT2 is the center thickness of the second lens, and EP12 is the spacing distance between the first spacer element and the second spacer element along the optical axis.

[0045] According to one technical solution of the present invention, the optical system satisfies:

[0046] -2.39≤SAG32 / T34≤-1.8;

[0047] Wherein, T34 is the air gap between the third lens and the fourth lens on the optical axis, and SAG32 is the axial displacement from the intersection of the image-side surface of the third lens and the optical axis to the vertex of the effective radius of the optical region on the image-side surface of the third lens.

[0048] According to one technical solution of the present invention, the optical system satisfies:

[0049] 2.04≤f345 / L≤2.75;

[0050] Where f345 is the combined focal length of the third lens, the fourth lens and the fifth lens, and L is the maximum height of the lens barrel.

[0051] The beneficial effects of this invention are:

[0052] The optical system of this application uses five lenses with optical power and at least one spacer element. The first to fifth lenses are arranged in sequence with intervals. By controlling the combined focal length of the third and fourth lenses and the radius of curvature of the image-side surfaces of the third and fourth lenses, the direction angle of light transmission within the two lenses can be controlled, ensuring the convergence of the focal points of the third and fourth lenses, which helps to correct system aberrations. However, since the third and fourth lenses are too curved, gap sensitivity problems are prone to occur during assembly, which in turn affects MTF. By controlling the focal length, refractive index, and radius of curvature of the image-side surface of the third lens, the surface shape trend of the third lens can be ensured. At the same time, by controlling the outer diameter and inner diameter of the object-side surface of the third spacer element, the assembly contact area between the third spacer element and the third lens can be ensured, thereby reducing the gap sensitivity of the third and fourth lenses, ensuring optical MTF, and improving imaging quality. Attached Figure Description

[0053] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0054] Figure 1A A structural layout diagram and schematic diagram of some parameters of an optical system according to the present invention are shown;

[0055] Figure 1B , Figure 1C and Figure 1D Schematic diagrams showing partial parameters of a first lens, a third lens, and a fourth lens of an optical imaging lens according to the present invention are shown respectively;

[0056] Figure 2A , Figure 2B Schematic diagrams of two optical systems according to Embodiment 1 of this application are shown;

[0057] Figure 2C , Figure 2D and Figure 2E The on-axis chromatic aberration curve, astigmatism curve, and magnification chromatic aberration curve of the optical system according to Embodiment 1 of this application are shown respectively.

[0058] Figure 3A , Figure 3B Schematic diagrams of two optical systems according to Embodiment 2 of this application are shown;

[0059] Figure 3C , Figure 3D and Figure 3E The on-axis chromatic aberration curve, astigmatism curve, and magnification chromatic aberration curve of the optical system according to Embodiment 2 of this application are shown respectively.

[0060] Figure 4A , Figure 4B Schematic diagrams of two optical systems according to Embodiment 3 of this application are shown;

[0061] Figure 4C , Figure 4D and Figure 4E The on-axis chromatic aberration curve, astigmatism curve, and magnification chromatic aberration curve of the optical system according to Embodiment 3 of this application are shown respectively.

[0062] Figure 5A , Figure 5B Schematic diagrams of two optical systems according to Embodiment 4 of this application are shown;

[0063] Figure 5C , Figure 5D and Figure 5E The on-axis chromatic aberration curve, astigmatism curve, and magnification chromatic aberration curve of the optical system according to Embodiment 4 of this application are shown respectively.

[0064] Figure 6 The defocus curve of an optical system according to one embodiment of the present invention is shown;

[0065] Figure 7 The defocus curve of an optical lens is shown;

[0066] Figure 8 The defocus curve of another optical lens is shown. Detailed Implementation

[0067] To better understand this application, various aspects of this application 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 this application and are not intended to limit the scope of this 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.

[0068] 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 this application, 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.

[0069] 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.

[0070] 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 imaging 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.

[0071] In the text, each lens has an optical region and a structural region on its object side or image side. The optical region refers to the area through which light passes, and the structural region refers to the area used for assembly.

[0072] It should also be understood that the terms "comprising," "including," "having," "containing," and / or "comprising," when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. Furthermore, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features, not individual elements in the list. Additionally, when describing embodiments of this application, the word "may" is used to mean "one or more embodiments of this application." And the term "exemplary" is intended to refer to an example or illustration.

[0073] 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 application 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 formalized sense, unless expressly so specified herein.

[0074] It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other. The following embodiments only illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent application. 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 application, and these all fall within the protection scope of this application.

[0075] like Figures 1A to 1D As shown, the optical imaging lens group of an exemplary embodiment of the present invention includes five lenses with optical power, which are sequentially included from the object side to the image side along the optical axis as follows: a first lens with negative optical power, a second lens with positive optical power, a third lens with positive optical power, a fourth lens with negative optical power, and a fifth lens with positive optical power, wherein each lens is independent of each other and there is an air gap between each lens on the optical axis.

[0076] The plurality of spacer elements includes a first spacer element, a second spacer element, a third spacer element, and a fourth spacer element. The first spacer element is located between the first lens and the second lens and is in direct contact with the image-side surface of the first lens. The second spacer element is located between the second lens and the third lens and is in direct contact with the image-side surface of the second lens. The third spacer element is located between the third lens and the fourth lens and is in direct contact with the image-side surface of the third lens. The fourth spacer element is located between the fourth lens and the fifth lens and is in direct contact with the image-side surface of the fourth lens. Direct contact means at least partial contact.

[0077] The optical 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.

[0078] In some embodiments of the present invention, the optical system may also include color filters and / or protective glass.

[0079] The present invention provides an optical system including a lens barrel, five lenses for imaging and multiple spacer elements, wherein the five lenses are arranged sequentially from the object side to the image side along the optical axis as a first lens, a second lens, a third lens, a fourth lens and a fifth lens;

[0080] The plurality of spacers include a second spacer located between the second lens and the third lens and in contact with the image-side surface of the second lens, and a third spacer located between the third lens and the fourth lens and in contact with the image-side surface of the third lens;

[0081] The optical system satisfies:

[0082] -5.88≤f34 / R8≤-3.79;

[0083] -3.25≤R6 / (D3s-d3s)≤-1.11;

[0084] 4.91≤f3*N3 / EP23≤7.77;

[0085] Wherein, f34 is the combined focal length of the third lens and the fourth lens, R8 is the radius of curvature of the image-side surface of the fourth lens, R6 is the radius of curvature of the image-side surface of the third lens, d3s is the inner diameter of the object-side surface of the third spacer element, D3s is the outer diameter of the object-side surface of the third spacer element, f3 is the effective focal length of the third lens, N3 is the refractive index of the third lens, and EP23 is the spacing distance between the second spacer element and the third spacer element along the optical axis.

[0086] This invention relates to an optical system consisting of five lenses. By controlling the combined focal length of the third and fourth lenses and the radius of curvature of their image-side surfaces, the direction and angle of light transmission within the two lenses (the third and fourth lenses) can be controlled, ensuring the convergence of the focal points of the third and fourth lenses and aiding in the correction of system aberrations. However, due to the excessive curvature of the third and fourth lenses, gap sensitivity issues can easily arise during assembly, thus affecting MTF (Mean Transmission Frequency). By controlling the focal length, refractive index, and radius of curvature of the image-side surface of the third lens, the surface profile of the third lens can be maintained. Simultaneously, by controlling the outer and inner diameters of the object-side surface of the third spacer element, the assembly contact area between the third spacer element and the third lens can be ensured, thereby reducing the gap sensitivity of the third and fourth lenses, guaranteeing optical MTF, and improving image quality.

[0087] like Figure 6 As shown, satisfying -3.25≤R6 / (D3s-d3s)≤-1.11 and 4.91≤f3*N3 / EP23≤7.77, the gap sensitivity problem caused by the curvature of the third and fourth lenses is effectively reduced, the MTF peaks of each field of view are concentrated, and the MTF values ​​are good; as Figure 7 As shown, when f3*N3 / EP23 = 7.894902, it exceeds the upper limit, or as... Figure 8 As shown, when f3*N3 / EP23=4.8977412, which exceeds the lower limit and does not satisfy -3.25≤R6 / (D3s-d3s)≤-1.11 and 4.91≤f3*N3 / EP23≤7.77, the surface stability of the third lens or the contact area with the spacer element is unbalanced, resulting in optical path offset, which leads to the MTF peaks of each field of view being unconcentrated and the MTF value being poor.

[0088] In some embodiments of the present invention, the spacer element further includes a fourth spacer element located between the fourth lens and the fifth lens and in contact with the image side of the fourth lens; the optical system satisfies: -1.89≤SAG41 / CT4≤-1.62; -2.63≤EP34 / SAG42≤-2.11;

[0089] Wherein, CT4 is the center thickness of the fourth lens, SAG41 is the axial displacement from the intersection of the object-side surface of the fourth lens and the optical axis to the vertex of the effective radius of the optical region of the object-side surface of the fourth lens, SAG42 is the axial displacement from the intersection of the image-side surface of the fourth lens and the optical axis to the vertex of the effective radius of the optical region of the image-side surface of the fourth lens, and EP34 is the spacing distance between the third spacer element and the fourth spacer element along the optical axis.

[0090] When the above relationships are satisfied, the center thickness, flange thickness, and sagittal dimension of the image-side object side of the fourth lens can be controlled, thereby controlling the surface shape trend and overall structural uniformity of the fourth lens, which is beneficial for molding and ensuring assembly stability.

[0091] In some embodiments of the present invention, the optical system satisfies: 2.32≤CT5 / T45≤2.61; 1.56≤(D4m-d4m) / R9≤2.28;

[0092] Wherein, CT5 is the center thickness of the fifth lens, T45 is the air gap between the fourth and fifth lenses on the optical axis, R9 is the radius of curvature of the object side of the fifth lens, d4m is the inner diameter of the image side of the fourth spacer element, and D4m is the outer diameter of the image side of the fourth spacer element.

[0093] When the above relationships are satisfied, the optical surface structure of the fifth lens can be controlled by controlling the radius of curvature, center thickness and air gap of the object side of the fifth lens. By controlling the size within a reasonable range, a lens with a flat surface and reasonable structure that is easy to form can be obtained. At the same time, by controlling the inner and outer diameters of the image side of the fourth spacer element, the bearing size of the spacer element can be limited, which can improve the assembly stability.

[0094] In some embodiments of the present invention, the spacer element further includes a first spacer element located between the first lens and the second lens and in contact with the image side of the first lens; the optical system satisfies: -32.75≤f1 / EP01≤-15.16;

[0095] Wherein, EP01 is the distance between the object-side end face of the lens barrel and the first spacer element along the optical axis, and f1 is the effective focal length of the first lens.

[0096] When the above relationship is satisfied, the spacing distance along the optical axis between the first spacer element that directly contacts the front end face of the lens barrel and the image side of the first lens can be controlled, thereby directly controlling the thickness of the object side end face of the lens barrel and the flange face of the first lens, which is beneficial for forming; furthermore, by controlling the effective focal length of the first lens, the surface shape of the object side and image side of the first lens can be controlled, which helps the convergence and transmission of light.

[0097] In some embodiments of the present invention, the optical system satisfies: 0.68 ≤ R1 / (D1s-d1s) ≤ 1.63;

[0098] Wherein, R1 is the radius of curvature of the object side surface of the first lens, D1s is the outer diameter of the object side surface of the first spacer element, and d1s is the inner diameter of the object side surface of the first spacer element.

[0099] When the above relationship is satisfied, the radius of curvature of the side surface of the first lens can be controlled, thereby controlling the angular distribution of incident light rays at the front end of the optical system, controlling the optical field of view, and ensuring the large field of view characteristics of the system; by controlling the outer diameter and inner diameter of the side surface of the first spacer element, invalid light rays emitted from the first lens can be blocked, reducing the risk of stray light.

[0100] In some embodiments of the present invention, the optical system satisfies: 2.92 ≤ f2 / (d2s-d1m) ≤ 10.87;

[0101] Where f2 is the effective focal length of the second lens, d1m is the inner diameter of the image side of the first spacer element, and d2s is the inner diameter of the object side of the second spacer element.

[0102] When the above relationship is satisfied, the effective focal length of the second lens can be controlled, thereby controlling the trajectory of light rays entering the second lens from the first lens and ensuring the focusing of light rays; at the same time, by controlling the outer diameter of the image side of the first spacer element and the inner diameter of the object side of the second spacer element, stray light rays entering the edge of the second lens can be blocked, ensuring image quality.

[0103] In some embodiments of the present invention, the optical system satisfies: 2.83 ≤ R3 / d1m ≤ 4.16;

[0104] Wherein, R3 is the radius of curvature of the object side of the second lens, and d1m is the inner diameter of the image side of the first spacer element.

[0105] By controlling the radius of curvature of the second lens, the overall shape of the second lens can be controlled, which is beneficial to the processing and shaping of the second lens; the aperture stop is located between the first lens and the second lens, and the light is blocked by the image side of the first spacer element, which can control the aperture number and relative illumination.

[0106] In some embodiments of the present invention, the optical system satisfies: 1.1≤(T12+T23) / EP12≤1.98;

[0107] Wherein, T12 is the air gap between the first lens and the second lens on the optical axis, T23 is the air gap between the second lens and the third lens on the optical axis, and EP12 is the spacing distance between the first spacer element and the second spacer element along the optical axis.

[0108] Because the first, second, and third lenses have high optical sensitivity, when the above relationship is satisfied, the size of the air gap between the first and second lenses on the optical axis, and the size of the air gap between the second and third lenses on the optical axis can be controlled, thereby effectively controlling the impact of air gap changes on performance and reducing the impact of mechanical sensitivity.

[0109] In some embodiments of the present invention, the optical system satisfies: 1.24≤D1s / (R2*N1)≤1.75;

[0110] Wherein, D1s is the outer diameter of the object side of the first spacer element, R2 is the radius of curvature of the image side of the first lens, and N1 is the refractive index of the first lens.

[0111] By controlling the refractive index of the first lens and the radius of curvature of the image side of the first lens, the angle of light entering the head of the first lens can be controlled to ensure the incident angle of the principal ray of the system. At the same time, by controlling the outer diameter of the side of the first spacer element, the size of the head can be controlled to ensure the miniaturization of the lens head.

[0112] In some embodiments of the present invention, the optical system satisfies: 4.61≤(SAG12+CT2) / EP12≤7.51;

[0113] Wherein, SAG12 is the axial displacement from the intersection of the image-side surface of the first lens and the optical axis to the vertex of the effective radius of the optical region of the image-side surface of the first lens, CT2 is the center thickness of the second lens, and EP12 is the spacing distance between the first spacer element and the second spacer element along the optical axis.

[0114] By controlling the axial displacement of the point where the image-side surface of the first lens intersects the optical axis to the vertex of the effective radius of the optical region on the image-side surface of the first lens, the surface structure of the effective surface of the first lens can be controlled. This is beneficial for controlling the incident and direction of the effective light rays, ensuring the size of the field of view and the principal ray angle. At the same time, by controlling the center thickness and edge thickness of the second lens, the thickness ratio of the lens can be controlled within a range that is conducive to processing, reducing the risk of forming weld lines.

[0115] In some embodiments of the present invention, the optical system satisfies: -2.39 ≤ SAG32 / T34 ≤ -1.8;

[0116] Wherein, T34 is the air gap between the third lens and the fourth lens on the optical axis, and SAG32 is the axial displacement from the intersection of the image-side surface of the third lens and the optical axis to the vertex of the effective radius of the optical region on the image-side surface of the third lens.

[0117] When the above relationship is satisfied, the surface shape trend of the third lens can be controlled by controlling the axial displacement between the intersection of the third lens image side and the optical axis and the vertex of the effective radius of the optical area of ​​the third lens image side. Combined with controlling the air gap between the third lens and the fourth lens on the optical axis, the surface shape trend of the lens and the transmission of light can be controlled, which is beneficial to controlling the effective focal length of the lens.

[0118] In some embodiments of the present invention, the optical system satisfies: 2.04 ≤ f345 / L ≤ 2.75;

[0119] Where f345 is the combined focal length of the third lens, the fourth lens and the fifth lens, and L is the maximum height of the lens barrel.

[0120] Since the effective focal length and F-number of a camera lens are directly proportional when the aperture diameter is fixed, the longer the focal length, the larger the F-number. When the above relationship is satisfied, the combined focal length of the third, fourth and fifth lenses and its relationship with the maximum height of the lens barrel can be controlled. The focal length and F-number can be effectively controlled, and the reasonable distribution of each lens in the overall height of the lens barrel can be controlled at the same time.

[0121] The optical system according to the above embodiments of this application can employ multiple lenses, such as the five 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.

[0122] 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. Conversely, when the lens material is glass, the low dispersion characteristic of glass itself can effectively correct the geometric chromatic aberration of the optical system. The optical lens provided by the present invention can adopt an all-plastic lens structure, which not only gives the lens excellent imaging performance but also allows for a more compact lens structure, achieving a good balance between lens miniaturization and high image quality.

[0123] In some embodiments of the present invention, the first lens, second lens, third lens, fourth lens, and fifth 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 first lens, second lens, third lens, fourth lens, and fifth lens of the present invention can all be aspherical lenses, which can effectively reduce the aberrations of the optical lens, thereby reducing the number of lenses and the size of the lenses, and achieving lens miniaturization.

[0124] When an aspherical lens is used, the shapes of each aspherical surface of the optical lens satisfy the following equation:

[0125]

[0126] In the above formula, z is the axial distance from the vertex to the surface at a position perpendicular to the optical axis at a height y; c represents the curvature at the vertex of the aspherical surface; k is the conic coefficient; A4, A6, A8, A 10 A 12 A 14 A 16 ...represent aspheric coefficients of the fourth, sixth, eighth, tenth, twelfth, fourteenth, and sixteenth orders, respectively.

[0127] 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 lens are different; for specific differences, please refer to the parameter tables of each embodiment. The following embodiments are merely 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 equivalent substitutions and are included within the protection scope of the present invention.

[0128] Example 1

[0129] The following is for reference Figures 2A to 2E The optical system 1001 and optical system 1002 according to Embodiment 1 of this application are described. Figure 2A and Figure 2B Schematic diagrams of optical system 1001 and optical system 1002 according to Embodiment 1 of this application are shown respectively.

[0130] like Figure 2A and Figure 2BAs shown, the structural schematic diagrams of optical system 1001 and optical system 1002 both include a lens barrel structure P0, an optical imaging lens group, and multiple spacer elements. The optical imaging lens group includes a first lens E1 to a fifth lens E5; the multiple spacer elements include a first spacer element P1, a second spacer element P2, a third spacer element P3, and a fourth spacer element P4.

[0131] In Embodiment 1, the schematic diagrams of optical systems 1001 and 1002 employ the same optical imaging lens group. The optical imaging lens group, from the object side to the image side, sequentially includes: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, and a fifth lens E5. Specifically, the first lens E1 has negative optical power, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has positive optical power, with its object-side surface S3 being convex and its image-side surface S4 being convex. The third lens E3 has positive optical power, with its object-side surface S5 being convex and its image-side surface S6 being convex. The fourth lens E4 has negative optical power, with its object-side surface S7 being concave and its image-side surface S8 being convex. The fifth lens E5 has positive optical power, with its object-side surface S9 being convex and its image-side surface S10 being concave. Light from the object passes through surfaces S1 to S10 in sequence and is finally imaged on imaging surface S13 (not shown in the figure). S11 and S12 are two surfaces of the protective glass or filter (not shown in the figure), OBJ (not shown in the figure) is the object surface, and STO is the aperture, which is set between the first lens E1 and the second lens E2.

[0132] 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. The units of radius of curvature and thickness are millimeters (mm).

[0133] Surface serial number Surface type radius of curvature thickness Refractive index Abbe number Conic coefficient OBJ spherical endless endless S1 aspherical 1.2237 0.2607 1.677 19.24 -0.0041 S2 aspherical 1.0081 0.2100 0.0140 STO spherical endless 0.0385 S3 aspherical 3.0257 0.3451 1.546 56.14 -0.1149 S4 aspherical -3.1191 0.3449 0.9055 S5 aspherical 12.7099 0.8364 1.855 40.10 -14.9501 S6 aspherical -1.8520 0.2051 -0.0001 S7 aspherical -0.8683 0.3146 1.677 19.24 -0.9950 S8 aspherical -2.5413 0.1087 -0.0135 S9 aspherical 0.7160 0.2599 1.570 37.40 -0.9989 S10 aspherical 0.6420 0.1860 -1.0035 S11 spherical endless 0.2100 1.518 64.17 S12 spherical endless 0.5613 S13 spherical endless

[0134] Table 1

[0135] 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 A 22 A 24 A 26 A 28 and A 30 .

[0136]

[0137]

[0138] Table 2

[0139] Figure 2C 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. Figure 2D The astigmatism curves of the optical system of Embodiment 1 are shown, which represent the meridional image plane curvature and the sagittal image plane curvature. Figure 2E The magnification chromatic aberration curve of the optical system of Embodiment 1 is shown, which represents the deviation of different image heights on the imaging plane after light passes through the lens. According to Figures 2C to 2E As can be seen, the optical system given in Example 1 can achieve good imaging quality.

[0140] Example 2

[0141] The following is for reference Figures 3A to 3E The optical system 2001 and optical system 2002 according to Embodiment 2 of this application are described. Figure 3A and Figure 3B Schematic diagrams of optical system 2001 and optical system 2002 according to Embodiment 2 of this application are shown respectively.

[0142] like Figure 3A and Figure 3B As shown, the structural schematic diagrams of optical system 2001 and optical system 2002 both include a lens barrel structure P0, an optical imaging lens group, and multiple spacer elements. The optical imaging lens group includes a first lens E1 to a fifth lens E5; the multiple spacer elements include a first spacer element P1, a second spacer element P2, a third spacer element P3, and a fourth spacer element P4.

[0143] In Embodiment 2, the schematic diagrams of optical systems 2001 and 2002 employ the same optical imaging lens group. The optical imaging lens group, from the object side to the image side, sequentially includes: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, and a fifth lens E5. Specifically, the first lens E1 has negative optical power, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has positive optical power, with its object-side surface S3 being convex and its image-side surface S4 being convex. The third lens E3 has positive optical power, with its object-side surface S5 being convex and its image-side surface S6 being convex. The fourth lens E4 has negative optical power, with its object-side surface S7 being concave and its image-side surface S8 being convex. The fifth lens E5 has positive optical power, with its object-side surface S9 being convex and its image-side surface S10 being concave. Light from the object passes through surfaces S1 to S10 in sequence and is finally imaged on imaging surface S13 (not shown in the figure). S11 and S12 are two surfaces of the protective glass or filter (not shown in the figure), OBJ (not shown in the figure) is the object surface, and STO is the aperture, which is set between the first lens E1 and the second lens E2.

[0144] 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. The units of radius of curvature and thickness are millimeters (mm).

[0145] Surface serial number Surface type radius of curvature thickness Refractive index Abbe number Conic coefficient OBJ spherical endless endless S1 aspherical 1.1616 0.2447 1.677 19.24 0.0269 S2 aspherical 0.9516 0.2269 0.0594 STO spherical endless 0.0383 S3 aspherical 3.1040 0.3617 1.546 56.14 -1.4987 S4 aspherical -3.1736 0.3582 2.9265 S5 aspherical 10.8421 0.8319 1.855 40.10 -27.7534 S6 aspherical -1.7380 0.2044 0.0425 S7 aspherical -0.8436 0.2977 1.677 19.24 -0.9810 S8 aspherical -2.5198 0.0977 -0.0589 S9 aspherical 0.7158 0.2549 1.570 37.40 -0.9949 S10 aspherical 0.6440 0.1872 -1.0017 S11 spherical endless 0.2100 1.518 64.17 S12 spherical endless 0.5613 S13 spherical endless

[0146] Table 3

[0147] 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 A 22 A 24 A 26 A 28 and A 30 .

[0148]

[0149]

[0150] Table 4

[0151] Figure 3C 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. Figure 3D The astigmatism curves of the optical system of Embodiment 2 are shown, which represent the meridional image plane curvature and the sagittal image plane curvature. Figure 3E The magnification chromatic aberration curve of the optical system in Embodiment 2 is shown, representing the deviation of different image heights on the imaging plane after light passes through the lens. According to... Figures 3C to 3E It can be seen that the optical system given in Example 2 can achieve good imaging quality.

[0152] Example 3

[0153] The following is for reference Figures 4A to 4E The optical systems 3001 and 3002 according to Embodiment 3 of this application are described. Figure 4A and Figure 4B Schematic diagrams of optical system 3001 and optical system 3002 according to Embodiment 3 of this application are shown respectively.

[0154] like Figure 4A and Figure 4BAs shown, the structural schematic diagrams of optical system 3001 and optical system 3002 both include a lens barrel structure P0, an optical imaging lens group, and multiple spacer elements. The optical imaging lens group includes a first lens E1 to a fifth lens E5; the multiple spacer elements include a first spacer element P1, a second spacer element P2, a third spacer element P3, and a fourth spacer element P4.

[0155] In Embodiment 3, the schematic diagrams of optical systems 3001 and 3002 employ the same optical imaging lens group. The optical imaging lens group, from the object side to the image side, sequentially includes: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, and a fifth lens E5. Specifically, the first lens E1 has negative optical power, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has positive optical power, with its object-side surface S3 being convex and its image-side surface S4 being convex. The third lens E3 has positive optical power, with its object-side surface S5 being convex and its image-side surface S6 being convex. The fourth lens E4 has negative optical power, with its object-side surface S7 being concave and its image-side surface S8 being convex. The fifth lens E5 has positive optical power, with its object-side surface S9 being convex and its image-side surface S10 being concave. Light from the object passes through surfaces S1 to S10 in sequence and is finally imaged on imaging surface S13 (not shown in the figure). S11 and S12 are two surfaces of the protective glass or filter (not shown in the figure), OBJ (not shown in the figure) is the object surface, and STO is the aperture, which is set between the first lens E1 and the second lens E2.

[0156] 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. The units of radius of curvature and thickness are millimeters (mm).

[0157] Surface serial number Surface type radius of curvature thickness Refractive index Abbe number Conic coefficient OBJ spherical endless endless S1 aspherical 1.0619 0.2269 1.677 19.24 0.1500 S2 aspherical 0.8427 0.3328 0.1634 STO spherical endless 0.0197 S3 aspherical 3.5637 0.4409 1.546 56.14 -16.9957 S4 aspherical -2.3494 0.4180 5.7633 S5 aspherical 10.1343 0.8657 1.855 40.10 -99.0000 S6 aspherical -1.7354 0.1828 0.0820 S7 aspherical -0.8322 0.2843 1.677 19.24 -0.9840 S8 aspherical -2.6048 0.1039 -0.0855 S9 aspherical 0.7104 0.2408 1.570 37.40 -0.9957 S10 aspherical 0.6428 0.1997 -1.0051 S11 spherical endless 0.2100 1.518 64.17 S12 spherical endless 0.5613 S13 spherical endless

[0158] Table 5

[0159] 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 A 22 A 24 A 26 A 28 and A 30 .

[0160]

[0161]

[0162] Table 6

[0163] Figure 4C 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. Figure 4D The astigmatism curves of the optical system of Embodiment 3 are shown, which represent the meridional image plane curvature and the sagittal image plane curvature. Figure 4E The magnification chromatic aberration curve of the optical system in Embodiment 3 is shown, representing the deviation of different image heights on the imaging plane after light passes through the lens. According to... Figures 4C to 4E As can be seen, the optical system given in Example 3 can achieve good imaging quality.

[0164] Example 4

[0165] The following is for reference Figures 5A to 5E The optical systems 4001 and 4002 according to Embodiment 4 of this application are described. Figure 5A and Figure 5B Schematic diagrams of optical system 4001 and optical system 4002 according to Embodiment 4 of this application are shown respectively.

[0166] like Figure 5A and Figure 5B As shown, the structural schematic diagrams of optical systems 4001 and 4002 both include a lens barrel structure P0, an optical imaging lens group, and multiple spacer elements. The optical imaging lens group includes a first lens E1 to a fifth lens E5; the multiple spacer elements include a first spacer element P1, a second spacer element P2, a third spacer element P3, and a fourth spacer element P4.

[0167] In Embodiment 4, the schematic diagrams of optical systems 4001 and 4002 employ the same optical imaging lens group. The optical imaging lens group, from the object side to the image side, sequentially includes: a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, and a fifth lens E5. Specifically, the first lens E1 has negative optical power, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has positive optical power, with its object-side surface S3 being convex and its image-side surface S4 being convex. The third lens E3 has positive optical power, with its object-side surface S5 being convex and its image-side surface S6 being convex. The fourth lens E4 has negative optical power, with its object-side surface S7 being concave and its image-side surface S8 being convex. The fifth lens E5 has positive optical power, with its object-side surface S9 being convex and its image-side surface S10 being concave. Light from the object passes through surfaces S1 to S10 in sequence and is finally imaged on imaging surface S13 (not shown in the figure). S11 and S12 are two surfaces of the protective glass or filter (not shown in the figure), OBJ (not shown in the figure) is the object surface, and STO is the aperture, which is set between the first lens E1 and the second lens E2.

[0168] Table 7 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. The units of radius of curvature and thickness are millimeters (mm).

[0169] Surface serial number Surface type radius of curvature thickness Refractive index Abbe number Conic coefficient OBJ spherical endless endless S1 aspherical 1.1759 0.2672 1.677 19.24 0.2638 S2 aspherical 0.9142 0.2972 0.2821 STO spherical endless 0.0189 S3 aspherical 4.2171 0.4607 1.546 56.14 -40.1510 S4 aspherical -2.0927 0.3773 6.1505 S5 aspherical 10.2137 0.8542 1.855 40.10 -75.4283 S6 aspherical -1.7862 0.1721 0.2224 S7 aspherical -0.8296 0.2966 1.677 19.24 -1.0095 S8 aspherical -2.6580 0.1113 -0.1140 S9 aspherical 0.7079 0.2774 1.570 37.40 -0.9958 S10 aspherical 0.6447 0.1996 -1.0167 S11 spherical endless 0.2100 1.518 64.17 S12 spherical endless 0.5628 S13 spherical endless

[0170] Table 7

[0171] Table 8 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 A 22 A 24 A 26 A 28 and A 30 .

[0172]

[0173]

[0174] Table 8

[0175] Figure 5C The on-axis chromatic aberration curve of the optical system of Embodiment 4 is shown, which represents the deviation of the focal point of light of different wavelengths after passing through the lens. Figure 5D The astigmatism curves of the optical system of Embodiment 4 are shown, which represent the meridional image plane curvature and the sagittal image plane curvature. Figure 5E The magnification chromatic aberration curve of the optical system in Embodiment 4 is shown, representing the deviation of different image heights on the imaging plane after light passes through the lens. According to... Figures 5C to 5E As can be seen, the optical system given in Example 4 can achieve good imaging quality.

[0176] In summary, the optical parameters of optical systems 1001, 1002, 2001, 2002, 3001, 3002, 4001 and 4002 in Examples 1 to 4 are shown in Table 9 below.

[0177]

[0178]

[0179] Table 9

[0180] The structural parameters of the optical systems 1001, 1002, 2001, 2002, 3001, 3002, 4001 and 4002 in Examples 1 to 4 are shown in Table 10 below, in millimeters (mm).

[0181]

[0182] Table 10

[0183] The optical systems 1001, 1002, 2001, 2002, 3001, 3002, 4001, and 4002 of Embodiments 1 to 4 satisfy the relationships shown in Table 11.

[0184]

[0185] Table 11

[0186] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover 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 features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. An optical system comprising a lens barrel, an optical imaging lens group, and a plurality of spacer elements, characterized in that, The optical imaging lens group consists of, along the optical axis from the object side to the image side, a first lens with negative optical power, a second lens with positive optical power, a third lens with positive optical power, a fourth lens with negative optical power, and a fifth lens with positive optical power. The plurality of spacers include a second spacer located between the second lens and the third lens and in contact with the image-side surface of the second lens, and a third spacer located between the third lens and the fourth lens and in contact with the image-side surface of the third lens; The optical system satisfies: -5.88≤f34 / R8≤-3.79; -3.25≤R6 / (D3s-d3s)≤-1.11; 4.91≤f3*N3 / EP23≤7.77; Wherein, f34 is the combined focal length of the third lens and the fourth lens, R8 is the radius of curvature of the image-side surface of the fourth lens, R6 is the radius of curvature of the image-side surface of the third lens, d3s is the inner diameter of the object-side surface of the third spacer element, D3s is the outer diameter of the object-side surface of the third spacer element, f3 is the effective focal length of the third lens, N3 is the refractive index 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 spacer element further includes a fourth spacer element located between the fourth lens and the fifth lens and in contact with the image side of the fourth lens; The optical system satisfies: -1.89≤SAG41 / CT4≤-1.62; -2.63≤EP34 / SAG42≤-2.11; Wherein, CT4 is the center thickness of the fourth lens, SAG41 is the axial displacement from the intersection of the object-side surface of the fourth lens and the optical axis to the vertex of the effective radius of the optical region of the object-side surface of the fourth lens, SAG42 is the axial displacement from the intersection of the image-side surface of the fourth lens and the optical axis to the vertex of the effective radius of the optical region of the image-side surface of the fourth lens, and EP34 is the spacing distance between the third spacer element and the fourth spacer element along the optical axis.

3. The optical system according to claim 2, characterized in that, The optical system satisfies: 2.32≤CT5 / T45≤2.61; 1.56≤(D4m-d4m) / R9≤2.28; Wherein, CT5 is the center thickness of the fifth lens, T45 is the air gap between the fourth and fifth lenses on the optical axis, R9 is the radius of curvature of the object side of the fifth lens, d4m is the inner diameter of the image side of the fourth spacer element, and D4m is the outer diameter of the image side of the fourth spacer element.

4. The optical system according to claim 1, characterized in that, The spacer element further includes a first spacer element located between the first lens and the second lens and in contact with the image side of the first lens; The optical system satisfies: -32.75≤f1 / EP01≤-15.16; Wherein, EP01 is the distance between the object-side end face of the lens barrel and the first spacer element along the optical axis, and f1 is the effective focal length of the first lens.

5. The optical system according to claim 4, characterized in that, The optical system satisfies: 0.68≤R1 / (D1s-d1s)≤1.63; Wherein, R1 is the radius of curvature of the object side surface of the first lens, D1s is the outer diameter of the object side surface of the first spacer element, and d1s is the inner diameter of the object side surface of the first spacer element.

6. The optical system according to claim 4, characterized in that, The optical system satisfies: 2.92≤f2 / (d2s-d1m)≤10.87; Where f2 is the effective focal length of the second lens, d1m is the inner diameter of the image side of the first spacer element, and d2s is the inner diameter of the object side of the second spacer element.

7. The optical system according to claim 4, characterized in that, The optical system satisfies: 2.83≤R3 / d1m≤4.16; Wherein, R3 is the radius of curvature of the object side of the second lens, and d1m is the inner diameter of the image side of the first spacer element.

8. The optical system according to claim 4, characterized in that, The optical system satisfies: 1.1≤(T12+T23) / EP12≤1.98; Wherein, T12 is the air gap between the first lens and the second lens on the optical axis, T23 is the air gap between the second lens and the third lens on the optical axis, and EP12 is the spacing distance between the first spacer element and the second spacer element along the optical axis.

9. The optical system according to claim 4, characterized in that, The optical system satisfies: 1.24≤D1s / (R2*N1)≤1.75; Wherein, D1s is the outer diameter of the object side of the first spacer element, R2 is the radius of curvature of the image side of the first lens, and N1 is the refractive index of the first lens.

10. The optical system according to claim 4, characterized in that, The optical system satisfies: 4.61≤(SAG12+CT2) / EP12≤7.51; Wherein, SAG12 is the axial displacement from the intersection of the image-side surface of the first lens and the optical axis to the vertex of the effective radius of the optical region of the image-side surface of the first lens, CT2 is the center thickness of the second lens, and EP12 is the spacing distance between the first spacer element and the second spacer element along the optical axis.

11. The optical system according to any one of claims 1-10, characterized in that, The optical system satisfies: -2.39≤SAG32 / T34≤-1.8; Wherein, T34 is the air gap between the third lens and the fourth lens on the optical axis, and SAG32 is the axial displacement from the intersection of the image-side surface of the third lens and the optical axis to the vertex of the effective radius of the optical region on the image-side surface of the third lens.

12. The optical system according to any one of claims 1-10, characterized in that, The optical system satisfies: 2.04≤f345 / L≤2.75; Where f345 is the combined focal length of the third lens, the fourth lens and the fifth lens, and L is the maximum height of the lens barrel.

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