Optical system

Abstract

The embodiment of the utility model discloses an optical system, which comprises a lens cone with an accommodating space, and a lens group and at least one spacing element accommodated in the lens cone, the lens group comprises a first lens with positive focal power, a second lens with positive focal power, a third lens with negative focal power, a fourth lens with negative focal power, a fifth lens with positive focal power and a sixth lens with negative focal power which are sequentially arranged from the object side to the image side along the optical axis; wherein the number of lenses with focal power in the lens group is six; a center thickness CT2 of the second lens on the optical axis, a center thickness CT3 of the third lens on the optical axis, and a maximum thickness CP2 of the second spacer element satisfy: 1.36 < = (CT2 + CP2) / CT3 < = 1.71; the effective focal length f2 of the second lens, the interval EP12 between the first spacing element and the second spacing element, and the interval EP23 between the second spacing element and the third spacing element satisfy: 2.88 < = f2 / (EP12 + EP23) < = 4.15.

Description

Technical Field

[0001] The present application relates to the field of optical elements, and in particular, to an optical system including multiple lenses. Background Art

[0002] With the continuous development of technology, higher requirements are placed on the optical systems of portable electronic devices. On the one hand, the optical system needs to be smaller, and on the other hand, to meet consumer demand for high imaging quality, the optical system must have high stability.

[0003] For the optical system, in order to ensure miniaturization, the head of the optical system is also more sensitive. When the lens is deformed by radial force, the flatness of the supporting surface of the lens mechanism is easily changed, resulting in poor assembly stability of the front-end lens.

[0004] Therefore, how to optimize the structure of the optical system to achieve system miniaturization while ensuring assembly stability and reducing the sensitivity of lens gap has become an urgent problem to be solved. Utility Model Content

[0005] According to one aspect of the present application, an optical system is provided, which includes a lens barrel with an accommodating space, and a lens group and at least one spacer element accommodated in the lens barrel, wherein the lens group includes: a first lens with positive focal power, a second lens with positive focal power, a third lens with negative focal power, a fourth lens with negative focal power, a fifth lens with positive focal power, and a sixth lens with negative focal power, which are arranged in sequence from the object side to the image side along the optical axis; and the at least one spacer element includes: a first spacer element located between the first lens and the second lens and in direct contact with the image side of the first lens, a second spacer element located between the second lens and the third lens and in direct contact with the image side of the second lens. a spacer element, and a third spacer element between the third lens and the fourth lens and in direct contact with the image side of the third lens, wherein the number of lenses with optical power in the lens group is six; the center thickness CT2 of the second lens on the optical axis, the center thickness CT3 of the third lens on the optical axis, and the maximum thickness CP2 of the second spacer element satisfy: 1.36≤(CT2+CP2) / CT3≤1.71; the effective focal length f2 of the second lens, the interval EP12 between the first spacer element and the second spacer element, and the interval EP23 between the second spacer element and the third spacer element satisfy: 2.88≤f2 / (EP12+EP23)≤4.15.

[0006] In one or more embodiments, an inner diameter d0m of the rear end surface of the lens barrel closest to the imaging surface and a curvature radius R12 of the image-side surface of the sixth lens satisfy the following relationship: 0.65≤d0m / R12≤4.91.

[0007] In one or more embodiments, the interval EP01 between the front end surface of the lens barrel and the first spacing element, the center thickness CT1 of the first lens on the optical axis, and the air interval T12 between the first lens and the second lens on the optical axis satisfy: 11.59≤(EP01+CT1) / T12≤34.52.

[0008] In one or more embodiments, the air interval T34 between the third lens and the fourth lens on the optical axis, the effective focal length f3 of the third lens, and the maximum thickness CP3 of the third spacer element satisfy: -17.42≤f3 / (T34+CP3)≤-2.38.

[0009] In one or more embodiments, the at least one spacer element further includes a fourth spacer element located between the fourth lens and the fifth lens and in direct contact with the image side of the fourth lens, and the center thickness CT4 of the fourth lens on the optical axis, the air gap T45 between the fourth lens and the fifth lens on the optical axis, and the interval EP34 between the third spacer element and the fourth spacer element satisfy: 0.85≤(CT4+T45) / EP34≤1.86.

[0010] In one or more embodiments, at least one spacer element further includes a fourth spacer element located between the fourth lens and the fifth lens and in direct contact with the image side of the fourth lens, and a fifth spacer element located between the fifth lens and the sixth lens and in direct contact with the image side of the fifth lens. The maximum thickness CP4 of the fourth spacer element, the interval EP45 between the fourth spacer element and the fifth spacer element, and the center thickness CT5 of the fifth lens on the optical axis satisfy: 0.99≤(CP4+EP45) / CT5≤1.53.

[0011] In one or more embodiments, a curvature radius R1 of the object-side surface of the first lens and an outer diameter D1s of the object-side surface of the first spacer element satisfy: 0.34≤R1 / D1s≤0.77.

[0012] In one or more embodiments, a curvature radius R3 of the object-side surface of the second lens and an inner diameter d1m of the image-side surface of the first spacer element satisfy: 0.75≤R3 / d1m≤3.00.

[0013] In one or more embodiments, the curvature radius R4 of the image-side surface of the second lens, the curvature radius R5 of the object-side surface of the third lens, and the inner diameter d2m of the image-side surface of the second spacer element satisfy: 2.23≤(R4-R5) / d2m≤5.13.

[0014] In one or more embodiments, the Abbe number V3 of the third lens satisfies: 21.5≤V3<34; the curvature radius R6 of the image-side surface of the third lens and the inner diameter d3s of the object-side surface of the third spacer element satisfy: 0.83≤R6 / d3s≤1.75.

[0015] In one or more embodiments, the at least one spacer element further includes a fourth spacer element located between the fourth lens and the fifth lens and in direct contact with the image side of the fourth lens, and the Abbe number V4 of the fourth lens satisfies: 23.7≤V4≤42.2; the curvature radius R8 of the image side surface of the fourth lens and the inner diameter d4s of the object side surface of the fourth spacer element satisfy: 1.41≤|R8 / d4s|≤6.52.

[0016] In one or more embodiments, the at least one spacer element further includes a fourth spacer element located between the fourth lens and the fifth lens and in direct contact with the image side of the fourth lens, and a curvature radius R9 of the object side surface of the fifth lens and an outer diameter D4m of the image side surface of the fourth spacer element satisfy: 0.43≤R9 / D4m≤0.84.

[0017] In one or more embodiments, the at least one spacer element further includes a fifth spacer element located between the fifth lens and the sixth lens and in direct contact with the image side of the fifth lens, the effective focal length f6 of the sixth lens, the center thickness CT6 of the sixth lens on the optical axis, the air gap T56 between the fifth lens and the sixth lens on the optical axis, and the maximum thickness CP5 of the fifth spacer element satisfy: -4.4≤f6 / (CT6+T56+CP5)≤-2.66.

[0018] In one or more embodiments, the at least one spacer element further includes a fifth spacer element located between the fifth lens and the sixth lens and in direct contact with the image side of the fifth lens, and the curvature radius R11 of the object side surface of the sixth lens and the inner diameter d5m of the image side surface of the fifth spacer element satisfy: 0.62≤|R11 / d5m|≤1.95.

[0019] In one or more embodiments, the object-side surface of the first lens is convex, and the image-side surface is concave; the object-side surface of the second lens is convex; the image-side surface of the third lens is concave; the object-side surface of the fifth lens is convex, and the image-side surface is convex; and the image-side surface of the sixth lens is concave.

[0020] The optical system provided in the present application includes a lens group and at least one spacer element. The lens group may include six lenses with optical focal length, and also includes a lens barrel for accommodating the lens group and the spacer element. The optical system can simultaneously meet the following requirements: 1.36≤(CT2+CP2) / CT3≤1.71 and 2.88≤f2 / (EP12+EP23)≤4.15, which is beneficial for improving the system assembly stability while ensuring the miniaturization and assembly stability of the overall lens structure, reducing the sensitivity of the front-end lens gap, and thereby improving the consistency of the lens performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Other features, objects and advantages of the present application will become more apparent upon reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0022] Figure 1A A schematic diagram showing the structure and some parameters of an optical system according to an embodiment of the present application is shown;

[0023] Figure 1B A schematic diagram showing the center point and edge points of the lens;

[0024] Figure 2A 1 shows a schematic structural diagram of an optical system according to Example 1 of the present application;

[0025] Figure 2B 1 shows a schematic structural diagram of an optical system according to Example 2 of the present application;

[0026] Figures 3A to 3D The axial chromatic aberration curve, astigmatism curve, distortion curve, and magnification chromatic aberration curve of the optical systems according to Example 1 and Example 2 of the present application are respectively shown;

[0027] Figure 4A 1 shows a schematic structural diagram of an optical system according to Example 3 of the present application;

[0028] Figure 4B 1 shows a schematic structural diagram of an optical system according to Example 4 of the present application;

[0029] 5A to 5D The axial chromatic aberration curve, astigmatism curve, distortion curve, and magnification chromatic aberration curve of the optical systems according to Example 3 and Example 4 of the present application are respectively shown;

[0030] Figure 6A 1 shows a schematic structural diagram of an optical system according to Example 5 of the present application;

[0031] Figure 6B 1 shows a schematic structural diagram of an optical system according to Example 6 of the present application;

[0032] 7A to 7DThe axial chromatic aberration curve, astigmatism curve, distortion curve, and magnification chromatic aberration curve of the optical systems according to Example 5 and Example 6 of the present application are respectively shown;

[0033] Figure 8A 1 shows a schematic structural diagram of an optical system according to Example 7 of the present application;

[0034] Figure 8B shows a schematic structural diagram of an optical system according to Example 8 of the present application; and

[0035] 9A to 9D The axial chromatic aberration curve, astigmatism curve, distortion curve and magnification chromatic aberration curve of the optical systems according to Example 7 and Example 8 of the present application are respectively shown. DETAILED DESCRIPTION

[0036] For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely descriptions of exemplary embodiments of the present application and are not intended to limit the scope of the present application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0037] It should be noted that in this specification, the terms "first," "second," "third," etc., are used solely to distinguish one feature from another and do not limit the features. Thus, the first lens discussed below could also be referred to as the second lens or the third lens without departing from the teachings of this application.

[0038] In the drawings, the thickness, size, and shape of the lenses are slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical and aspherical surfaces shown in the drawings are provided by way of example. That is, the shapes of the spherical and aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustration only and are not drawn strictly to scale.

[0039] Those skilled in the art will understand that a lens is an optical component formed by two refractive surfaces surrounding a transparent medium. The refractive surface can be a spherical surface (including a plane, i.e. a spherical surface with an infinite radius of curvature) or an aspherical surface. The line connecting the centers of curvature of the two refractive surfaces is the optical axis of the lens. In this article, the surface of the two refractive surfaces closer to the object is called the object side of the lens, and the surface closer to the imaging surface is called the image side of the lens. Each side has a center point and an edge point. For example, Figure 1B The center point A and edge point B of the image-side surface of the first lens E1 are shown. The center point is a special point in the middle of the lens where light does not change its propagation direction. The edge point is the point of the lens with the maximum effective aperture away from the optical axis.

[0040] In this article, the paraxial area refers to the area near the optical axis. If the lens surface is convex and the position of the convex surface is not defined, it means that the lens surface is convex at least in the paraxial area; if the lens surface is concave and the position of the concave surface is not defined, it means that the lens surface is concave at least in the paraxial area. The judgment of the surface shape in the paraxial area can be judged according to the common methods in this field, for example, the positive and negative R value (R refers to the curvature radius of the paraxial area) is used to judge the convexity. For the object side, when the R value is positive, it is judged to be convex, and when the R value is negative, it is judged to be concave; for the image side, when the R value is positive, it is judged to be concave, and when the R value is negative, it is judged to be convex.

[0041] The solutions described in the embodiments of this application can be simulated using software / tools such as ZEMAX and CODE V. The solutions described in some embodiments can preferably be simulated using CODE V. During the simulation process using the above-mentioned software / tools, the lens surface shape can be appropriately adjusted based on the surface shape model provided by the software / tool used.

[0042] It should also be understood that the terms "comprises," "including," "having," "includes," and / or "comprising," when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not preclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. In addition, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features rather than modifying the individual elements in the list. In addition, when describing embodiments of the present application, "may" is used to mean "one or more embodiments of the present application." And, the term "exemplary" is intended to refer to an example or illustration.

[0043] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those skilled in the art to which this application belongs. It should also be understood that terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology and will not be interpreted in an idealized or overly formal sense unless expressly defined as such herein.

[0044] It should be noted that, in the absence of conflicts, the embodiments and features of the embodiments in this application can be combined with each other. The following embodiments only express several implementation methods of the present application, and their descriptions are relatively specific and detailed, but they should not be understood as limiting the scope of the patent of this application. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present application, several variations and improvements can be made, which all fall within the scope of protection of this application. For example, the lens groups (i.e., the first to sixth lenses), the lens barrel structure, and the spacer elements in the various embodiments of the present application can be arbitrarily combined, and are not limited to the lens groups in one embodiment being combined only with the lens barrel structure, spacer elements, etc. of that embodiment.

[0045] The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments. Figure 1A The figure shows the structure arrangement of an optical system according to the present application and a schematic diagram of some parameters. It should be understood by those skilled in the art that some parameters commonly used in the art, such as the center thickness CT1 of the first lens on the optical axis and the maximum height L of the lens barrel along the optical axis, are not shown in the figure. Figure 1A As shown in Figure 1A Only some parameters of the lens barrel and the spacer element of an optical system of the present application are shown as examples to facilitate a better understanding of the present invention. Figure 1A As shown in the figure, EP01 represents the distance between the front end surface of the lens barrel close to the object side and the object side surface of the first spacer element along the optical axis; EP12 represents the distance between the image side surface of the first spacer element and the object side surface of the second spacer element along the optical axis; EP23 represents the distance between the image side surface of the second spacer element and the object side surface of the third spacer element along the optical axis; EP34 represents the distance between the image side surface of the third spacer element and the object side surface of the fourth spacer element along the optical axis; EP45 represents the distance between the image side surface of the fourth spacer element and the object side surface of the fifth spacer element along the optical axis; CP2 represents the distance between the image side surface of the fourth spacer element and the object side surface of the fifth spacer element along the optical axis. CP3 represents the maximum thickness of the second spacer element along the optical axis; CP4 represents the maximum thickness of the fourth spacer element along the optical axis; CP5 represents the maximum thickness of the fifth spacer element along the optical axis; d0m represents the inner diameter of the rear end face of the lens barrel close to the image side closest to the imaging surface; D1s represents the outer diameter of the object side face of the first spacer element; d1m represents the inner diameter of the image side face of the first spacer element; d2s represents the inner diameter of the object side face of the second spacer element; d2m represents the inner diameter of the image side face of the second spacer element, and so on.

[0046] The features, principles and other aspects of the present application are described in detail below.

[0047] refer to Figure 2A and Figure 2B 、 Figure 4A and Figure 4B 、 Figure 6A and Figure 6B ,as well as Figure 8A and Figure 8B As shown, a first aspect of the present application provides an optical system that may include a lens barrel, a lens assembly, and at least one spacer element, wherein the lens assembly and the one or more spacer elements are housed within the lens barrel. The lens assembly may include six lenses having optical power, namely, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens, arranged in sequence from the object side to the image side along the optical axis. Any two adjacent lenses among the first lens to the sixth lens may have a spacing distance therebetween.

[0048] In an exemplary embodiment, the first lens may have positive optical power. The second lens may have positive optical power. The third lens may have negative optical power. The fourth lens may have negative optical power. The fifth lens may have positive optical power. The sixth lens may have negative optical power.

[0049] According to an exemplary embodiment of the present application, an optical system includes at least one spacer element. The at least one spacer element may include any one or more of the following: a first spacer element located between a first lens and a second lens and in direct contact with the image side of the first lens; a second spacer element located between a second lens and a third lens and in direct contact with the image side of the second lens; a third spacer element located between a third lens and a fourth lens and in direct contact with the image side of the third lens; a fourth spacer element located between a fourth lens and a fifth lens and in direct contact with the image side of the fourth lens; and a fifth spacer element located between a fifth lens and a sixth lens and in direct contact with the image side of the fifth lens. The spacer element may contact a non-optical region on the image side of an adjacent lens. For example, the second spacer element may abut against a non-optical region on the image side of the second lens. Exemplarily, the spacer element may include a spacer, a light shielding sheet, a spacer ring, or a pressure ring. By properly configuring the number, thickness, inner diameter, and outer diameter of the spacer elements, stray light can be blocked, imaging quality of the optical system can be improved, and assembly stability of the optical system can be enhanced.

[0050] It should be understood that the surface of each spacer element closest to the subject can be referred to as the object-side surface of the spacer element, and the surface of each spacer element closest to the imaging plane can be referred to as the image-side surface of the spacer element. The surface of the lens barrel closest to the subject can be referred to as the object-side end surface or front end surface of the lens barrel, and the surface of the lens barrel closest to the imaging plane can be referred to as the image-side end surface or rear end surface of the lens barrel.

[0051] In an exemplary embodiment, a lens assembly may include at least one trimmed lens. The outer peripheral surface of the trimmed lens may have a trimmed portion and an untrimmed portion, with the outer diameter of the trimmed portion being smaller than the outer diameter of the untrimmed portion. When the outer peripheral surface of a lens has a trimmed portion, the outer diameter of the lens generally refers to the outer diameter of the untrimmed portion of the lens.

[0052] In an exemplary embodiment, at least one spacer element may include at least one trimmed spacer element. The outer circumference of the trimmed spacer element may have a trimmed portion and a non-trimmed portion, and the outer diameter of the trimmed portion of the spacer element is smaller than the outer diameter of the non-trimmed portion of the spacer element. The outer diameter of the spacer element generally refers to the maximum outer diameter of the non-trimmed portion.

[0053] In an exemplary embodiment, the optical system according to the present application can satisfy the following conditional formulas: 1.36≤(CT2+CP2) / CT3≤1.71; 2.88≤f2 / (EP12+EP23)≤4.15, wherein CT2 is the center thickness of the second lens on the optical axis, CP2 is the maximum thickness of the second spacer element, and CT3 is the center thickness of the third lens on the optical axis. By controlling the above parameters, on the one hand, by reasonably controlling the ratio of the sum of the center thickness of the second lens and the thickness of the second spacer element to the center thickness of the third lens, the thickness difference of the first few lenses is reduced, which is beneficial to the miniaturization of the overall structure of the lens and the assembly stability; on the other hand, by reasonably controlling the ratio of the effective focal length of the second lens to the spacing between the first and second spacer elements and the sum of the spacing between the second and third spacer elements, the influence of assembly deformation on lens performance is reduced. Satisfying the above two conditional formulas at the same time is beneficial to improving the assembly stability of the optical system, reducing gap sensitivity, and improving the consistency of lens performance.

[0054] In an exemplary embodiment, the optical system according to the present application can satisfy the following conditional equation: 0.65 ≤ d0m / R12 ≤ 4.91, where d0m is the inner diameter of the rear end face of the lens barrel closest to the imaging plane, and R12 is the radius of curvature of the image-side surface of the sixth lens element. Satisfying this conditional equation, by properly controlling the ratio of the inner diameter of the rear end face of the lens barrel closest to the imaging plane to the radius of curvature of the image-side surface of the sixth lens element, helps ensure overall miniaturization of the lens, improves the relative illumination (RI) of the lens's peripheral field of view, limits stray light at the rear end of the lens barrel, and thus improves the overall imaging capability of the lens.

[0055] In an exemplary embodiment, the optical system according to the present application can satisfy the following conditional equation: 11.59 ≤ (EP01 + CT1) / T12 ≤ 34.52, where EP01 is the distance between the front end face of the lens barrel and the first spacer, CT1 is the center thickness of the first lens on the optical axis, and T12 is the air gap between the first lens and the second lens on the optical axis. This conditional equation is satisfied by properly controlling the ratio of the sum of the distance between the front end face of the lens barrel and the first spacer and the center thickness of the first lens to the air gap between the first lens and the second lens on the optical axis. This limits the distance between the object side surface of the first lens and the front end face of the lens barrel on the optical axis, ensuring that the object plane of the lens does not protrude beyond the front end face of the lens barrel, thereby protecting the lens.

[0056] In an exemplary embodiment, the optical system according to the present application can satisfy the following conditional equation: -17.42 ≤ f3 / (T34 + CP3) ≤ -2.38, where f3 is the effective focal length of the third lens, T34 is the air spacing between the third and fourth lenses on the optical axis, and CP3 is the maximum thickness of the third spacer. By properly controlling the ratio of the effective focal length of the third lens to the sum of the air spacing between the third and fourth lenses on the optical axis and the maximum thickness of the third spacer, this conditional equation ensures that more light is focused on the object-side surface of the fourth lens, thereby improving the imaging quality of the lens.

[0057] In an exemplary embodiment, the optical system according to the present application can satisfy the following conditional equation: 0.85 ≤ (CT4 + T45) / EP34 ≤ 1.86, where CT4 is the center thickness of the fourth lens on the optical axis, T45 is the air spacing between the fourth and fifth lenses on the optical axis, and EP34 is the spacing between the third and fourth spacing elements. By properly controlling the ratio of the sum of the center thickness of the fourth lens on the optical axis, the air spacing between the fourth and fifth lenses on the optical axis, and the spacing between the third and fourth spacing elements, the overall thickness of the lens can be uniformly controlled. This also helps reduce the thickness ratio of the fifth lens, preventing weld marks during lens molding.

[0058] In an exemplary embodiment, the optical system according to the present application can satisfy the following conditional equation: 0.99 ≤ (CP4 + EP45) / CT5 ≤ 1.53, where CP4 is the maximum thickness of the fourth spacer, EP45 is the spacing between the fourth and fifth spacers, and CT5 is the center thickness of the fifth lens on the optical axis. By properly controlling the ratio of the sum of the maximum thickness of the fourth spacer, the spacing between the fourth and fifth spacers, and the center thickness of the fifth lens on the optical axis, the thickness of the lens structure at the assembly of the fourth and fifth lenses can be controlled. Specifically, because the effective diameter edge spacing of the fourth and fifth lenses is too large, a spacer of a certain thickness is used. By controlling the thickness of the spacer, the edge thickness of the fourth and fifth lenses is reduced, preventing an excessively large lens thickness ratio that would make molding difficult. This also reduces the risk of deformation during assembly and reduces lens sensitivity.

[0059] In an exemplary embodiment, the optical system according to the present application can satisfy the following conditional equation: 0.34 ≤ R1 / D1s ≤ 0.77, where R1 is the radius of curvature of the object-side surface of the first lens element, and D1s is the outer diameter of the object-side surface of the first spacer element. By satisfying this conditional equation, by properly controlling the ratio of the radius of curvature of the object-side surface of the first lens element to the outer diameter of the object-side surface of the first spacer element, the outer diameter gradient of the first lens element and the subsequent lens assembly can be effectively controlled, avoiding deterioration in assembly stability due to excessive outer diameter gradient changes, thereby ensuring stable lens performance.

[0060] In an exemplary embodiment, the optical system according to the present application can satisfy the following conditional equation: 0.75 ≤ R3 / d1m ≤ 3.00, where R3 is the radius of curvature of the object-side surface of the second lens element, and d1m is the inner diameter of the image-side surface of the first spacer element. Meeting this conditional equation, by properly controlling the ratio of the radius of curvature of the object-side surface of the second lens element to the inner diameter of the image-side surface of the first spacer element, can help reduce the risk of stray light generated by light outside the field of view, thereby improving the imaging capability of the lens.

[0061] In an exemplary embodiment, the optical system according to the present application can satisfy the following conditional equation: 2.23 ≤ (R4 - R5) / d2m ≤ 5.13, where R4 is the radius of curvature of the image-side surface of the second lens element, R5 is the radius of curvature of the object-side surface of the third lens element, and d2m is the inner diameter of the image-side surface of the second spacer element. By satisfying this conditional equation, by rationally controlling the ratio of the difference between the radius of curvature of the image side of the second lens element and the radius of curvature of the object side surface of the third lens element to the inner diameter of the image-side surface of the second spacer element, the luminous flux of light emitted from the image-side surface of the second lens element reaching the object-side surface of the third lens element is adjusted, thereby enhancing the focusing capability of light at the front end of the lens assembly and ensuring the imaging quality of the lens.

[0062] In an exemplary embodiment, the optical system according to the present application can satisfy the following conditions: 21.5 ≤ V3 < 34; 0.83 ≤ R6 / d3s ≤ 1.75, where V3 is the Abbe number of the third lens element, R6 is the radius of curvature of the image-side surface of the third lens element, and d3s is the inner diameter of the object-side surface of the third spacer element. By ensuring that the Abbe number of the third lens element is less than 35 and satisfying the condition 0.83 ≤ R6 / d3s ≤ 1.75, and by properly controlling the ratio of the radius of curvature of the image-side surface of the third lens element to the inner diameter of the object-side surface of the third spacer element, it is possible to control the stray light generated by light rays of different wavelengths emitted from the image-side surface of the third lens element reaching the rear lens group, thereby reducing the risk of stray light and improving the imaging capability of the lens.

[0063] In an exemplary embodiment, the optical system according to the present application can satisfy the following conditional equations: 23.7 ≤ V4 ≤ 42.2; 1.41 ≤ |R8 / d4s| ≤ 6.52, where V4 is the Abbe number of the fourth lens element, R8 is the radius of curvature of the image-side surface of the fourth lens element, and d4s is the inner diameter of the object-side surface of the fourth spacer element. By ensuring the Abbe number of the fourth lens element is less than or equal to 56 and satisfying the conditional equation 1.41 ≤ |R8 / d4s| ≤ 6.52, and by properly controlling the absolute value of the ratio of the radius of curvature of the image-side surface of the fourth lens element to the inner diameter of the object-side surface of the fourth spacer element, the contact area between the spacer element and the fourth lens element is ensured, preventing deformation of the spacer element due to stress during assembly, thereby improving the assembly stability of the lens.

[0064] In an exemplary embodiment, the optical system according to the present application can satisfy the following conditional equation: 0.43 ≤ R9 / D4m ≤ 0.84, where R9 is the radius of curvature of the object-side surface of the fifth lens element, and D4m is the outer diameter of the image-side surface of the fourth spacer element. Satisfying this conditional equation, by properly controlling the ratio of the radius of curvature of the fifth lens element to the outer diameter of the image-side surface of the fourth spacer element, helps reduce the difference in outer diameter between the fourth and fifth lenses, making the overall variation in the inner diameter of the lens barrel more uniform and ensuring lens miniaturization.

[0065] In an exemplary embodiment, the optical system according to the present application can satisfy the following conditional equation: -4.4 ≤ f6 / (CT6 + T56 + CP5) ≤ -2.66, where f6 is the effective focal length of the sixth lens, CT6 is the center thickness of the sixth lens on the optical axis, T56 is the air gap between the fifth and sixth lenses on the optical axis, and CP5 is the maximum thickness of the fifth spacer. Meeting this conditional equation helps ensure the assembly stability of the sixth lens by rationally controlling the ratio of the effective focal length of the sixth lens to the sum of the center thickness of the sixth lens on the optical axis, the air gap between the fifth and sixth lenses on the optical axis, and the maximum thickness of the fifth spacer. Because the distance between the effective diameter edge and the midpoint of the effective diameter of the sixth lens on the optical axis is relatively large, the lens is prone to deformation when subjected to force during assembly, thereby affecting lens performance. Therefore, by controlling the above parameter relationship, lens performance stability can be effectively guaranteed.

[0066] In an exemplary embodiment, the optical system according to the present application can satisfy the following conditional equation: 0.62 ≤ |R11 / d5m| ≤ 1.95, where R11 is the radius of curvature of the object-side surface of the sixth lens element, and d5m is the inner diameter of the image-side surface of the fifth spacer element. Satisfying this conditional equation, by properly controlling the absolute value of the ratio of the radius of curvature of the object-side surface of the sixth lens element to the inner diameter of the image-side surface of the fifth spacer element, facilitates control of the shape of the sixth lens element, improves the molding of the sixth lens element, and facilitates more rational assembly, thereby enhancing the stability of lens performance.

[0067] refer to Figure 2A and Figure 2B 、 Figure 4A and Figure 4B 、 Figure 6A and Figure 6B ,as well as Figure 8A and Figure 8B As shown, the second aspect of the present application provides an optical system, which may include a lens barrel, a lens group and at least one spacer element, wherein the lens group and the one or more spacer elements are all accommodated in the lens barrel. The lens group may include six lenses with optical power, namely a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens arranged in sequence from the object side to the image side along the optical axis. Any two adjacent lenses from the first lens to the sixth lens may have a spacing distance. The optical system also includes at least one spacer element, which may include any one or more of the following spacer elements: a first spacer element located between the first lens and the second lens and in direct contact with the image side of the first lens, a second spacer element located between the second lens and the third lens and in direct contact with the image side of the second lens, a third spacer element located between the third lens and the fourth lens and in direct contact with the image side of the third lens, a fourth spacer element located between the fourth lens and the fifth lens and in direct contact with the image side of the fourth lens, and a fifth spacer element located between the fifth lens and the sixth lens and in direct contact with the image side of the fifth lens, etc.

[0068] In an exemplary embodiment, the optical system according to the present application can satisfy the following conditional equation: 0.99 ≤ (CP4 + EP45) / CT5 ≤ 1.53, where CP4 is the maximum thickness of the fourth spacer, EP45 is the spacing between the fourth and fifth spacers, and CT5 is the center thickness of the fifth lens on the optical axis. By properly controlling the ratio of the sum of the maximum thickness of the fourth spacer, the spacing between the fourth and fifth spacers, and the center thickness of the fifth lens on the optical axis, the thickness of the lens structure at the assembly of the fourth and fifth lenses can be controlled. Specifically, because the effective diameter edge spacing of the fourth and fifth lenses is too large, a spacer of a certain thickness is used. By controlling the thickness of the spacer, the edge thickness of the fourth and fifth lenses is reduced, preventing an excessively large lens thickness ratio that would make molding difficult. This also reduces the risk of deformation during assembly and reduces lens sensitivity.

[0069] refer to Figure 2A and Figure 2B 、 Figure 4A and Figure 4B 、 Figure 6A and Figure 6B ,as well as Figure 8A and Figure 8BAs shown, the third aspect of the present application provides an optical system, which may include a lens barrel, a lens group and at least one spacer element, wherein the lens group and the one or more spacer elements are all accommodated in the lens barrel. The lens group may include six lenses with optical power, namely a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens arranged in sequence from the object side to the image side along the optical axis. Any two adjacent lenses from the first lens to the sixth lens may have a spacing distance. The optical system also includes at least one spacer element, which may include any one or more of the following spacer elements: a first spacer element located between the first lens and the second lens and in direct contact with the image side of the first lens, a second spacer element located between the second lens and the third lens and in direct contact with the image side of the second lens, a third spacer element located between the third lens and the fourth lens and in direct contact with the image side of the third lens, a fourth spacer element located between the fourth lens and the fifth lens and in direct contact with the image side of the fourth lens, and a fifth spacer element located between the fifth lens and the sixth lens and in direct contact with the image side of the fifth lens, etc.

[0070] In an exemplary embodiment, the optical system according to the present application can satisfy the following conditional equation: -4.4 ≤ f6 / (CT6 + T56 + CP5) ≤ -2.66, where f6 is the effective focal length of the sixth lens, CT6 is the center thickness of the sixth lens on the optical axis, T56 is the air gap between the fifth and sixth lenses on the optical axis, and CP5 is the maximum thickness of the fifth spacer. Meeting this conditional equation helps ensure the assembly stability of the sixth lens by rationally controlling the ratio of the effective focal length of the sixth lens to the sum of the center thickness of the sixth lens on the optical axis, the air gap between the fifth and sixth lenses on the optical axis, and the maximum thickness of the fifth spacer. Because the distance between the effective diameter edge and the midpoint of the effective diameter of the sixth lens on the optical axis is relatively large, the lens is prone to deformation when subjected to force during assembly, thereby affecting lens performance. Therefore, by controlling the above parameter relationship, lens performance stability can be effectively guaranteed.

[0071] It should be understood that this application does not specifically limit the number of spacer elements; any number of spacer elements may be included between any two lenses, and the entire optical system may also include any number of spacer elements. Spacer elements help the optical system intercept unwanted refractive and reflective light paths, reducing stray light and ghosting. Adding auxiliary support between the spacer elements and the lens barrel can help alleviate issues such as poor assembly stability and low performance yield caused by large step differences between the lenses.

[0072] In some embodiments, the optical system according to the present application may further include a filter and / or protective glass disposed between the sixth lens and the imaging surface for filtering light with different wavelengths, correcting color deviation, and protecting the photosensitive element located on the imaging surface.

[0073] In some embodiments, the optical system according to the present application may further include an aperture disposed between the object side and the first lens. The provision of the aperture is conducive to effectively converging the light entering the optical lens and is conducive to reducing the aperture of the lens.

[0074] According to the optical system of the above-described embodiment of the present application, its lens assembly can use multiple lenses, such as the six lenses described above. By properly allocating the focal length, surface shape, center thickness of each lens, and the on-axis spacing between lenses, the incident light can be effectively focused, the overall optical length can be reduced, and the workability can be improved, making the optical system more convenient for production and processing.

[0075] In an embodiment of the present application, at least one of the mirror surfaces of each lens in the first to sixth lenses is an aspherical mirror surface. The characteristic of an aspherical lens is that the curvature changes continuously from the center of the lens to the periphery of the lens. Unlike a spherical lens with a constant curvature from the center of the lens to the periphery of the lens, an aspherical lens has a better curvature radius characteristic, and has the advantages of improving distortion aberration and improving astigmatism aberration. After adopting an aspherical lens, the aberration that occurs during imaging can be eliminated as much as possible, thereby improving the imaging quality. Optionally, the object side surface and the image side surface of each lens in the first to sixth lenses are aspherical mirror surfaces.

[0076] Examples 1 to 8 of the optical system applicable to the above exemplary embodiment will be further described below with reference to the accompanying drawings.

[0077] Example 1

[0078] The following reference Figure 2A An optical system according to Example 1 of the present application is described.

[0079] like Figure 2A As shown, the optical system includes a lens barrel P0 and a lens group and at least one spacer element accommodated in the lens barrel P0.

[0080] The lens group includes, from the object side to the image side, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5 and a sixth lens E6.

[0081] The at least one spacer element includes a first spacer element P1 , a second spacer element P2 , a third spacer element P3 , a fourth spacer element P4 and a fifth spacer element P5 .

[0082] The first lens E1 has positive 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 negative optical power, with its object-side surface S5 being concave and its image-side surface S6 being concave. The fourth lens E4 has negative optical power, with its object-side surface S7 being concave and its image-side surface S8 being concave. The fifth lens E5 has positive optical power, with its object-side surface S9 being convex and its image-side surface S10 being convex. The sixth lens E6 has negative optical power, with its object-side surface S11 being concave and its image-side surface S12 being concave. The optical system further includes a filter (not shown) disposed between the sixth lens E6 and the imaging surface S15. The filter has an object-side surface S13 and an image-side surface S14. Light from an object sequentially passes through each of surfaces S1 to S14 and is ultimately imaged on the imaging surface S15.

[0083] Table 1 shows the basic parameters of the optical system of Example 1, wherein the units of curvature radius and thickness / distance are all millimeters (mm).

[0084]

[0085] Table 1

[0086] In Example 1, the object-side surface and the image-side surface of any lens among the first lens E1 to the sixth lens E6 are both aspherical surfaces. The surface shape of each aspherical lens can be defined by, but is not limited to, the following aspherical surface formula:

[0087]

[0088] Wherein, x is the distance vector height of the aspheric surface from the vertex of the aspheric surface at a height of h along the optical axis; c is the paraxial curvature of the aspheric surface, c = 1 / R (i.e., the paraxial curvature c is the reciprocal of the curvature radius R in Table 1 above); k is the cone coefficient; Ai is the correction coefficient of the i-th order of the aspheric surface. The following Tables 2-1 and 2-2 give the high-order coefficients A4, A6, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22, A23, A24, A25, A26, A27, A28, A29, A30, A31, A32, A33, A34, A35, A36, A37, A38, A39, A40, A41, A42, A43, A44, A45, A46, A47, A50, A51, A52, A53, A54, A55, A56, A57, A58, A59, A60, A61, A71, A72, A73, A74, A75, A80, A81, A9, A10, A11, A12, A13, A14, A15 10 、A 12 、A 14 、A 16 、A 18 、A 20 、A 22 、A 24 、A 26 、A 28 and A 30 .

[0089]

[0090]

[0091] Table 2-1

[0092] Face number A18 A20 A22 A24 A26 A28 A30 S1 -7.0176E-08 -1.4406E-07 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S2 -1.1213E-06 -2.2623E-08 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S3 -4.8719E-06 -4.1471E-07 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S4 -4.1864E-06 -1.5857E-06 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S5 -6.7234E-06 -2.4147E-06 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S6 1.0601E-06 -1.5428E-06 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S7 4.4223E-06 -1.9565E-07 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S8 1.2976E-05 -3.9707E-06 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S9 7.5324E-05 -3.7315E-05 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S10 3.6296E-05 -1.1622E-04 -1.1534E-06 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S11 -3.2774E-04 6.1696E-05 3.4716E-06 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S12 -1.9829E-03 -1.6726E-03 -5.1292E-04 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00

[0093] Table 2-2

[0094] Figure 3A The axial chromatic aberration curve of the optical system of Example 1 is shown, which indicates the deviation of the convergence point of light of different wavelengths after passing through the lens. Figure 3B The astigmatism curve of the optical system of Example 1 is shown, which indicates meridional field curvature and sagittal field curvature. Figure 3C The distortion curve of the optical system of Example 1 is shown, which represents the distortion magnitude values corresponding to different image heights. Figure 3D The chromatic aberration curve of the optical system of Example 1 is shown, which represents the deviation of different image heights on the imaging surface after the light passes through the lens. Figures 3A to 3D It can be seen that the optical system provided in Example 1 can achieve good imaging quality.

[0095] Example 2

[0096] The following reference Figure 2B The optical system according to Example 2 of the present application is described. In this embodiment and the following embodiments, some descriptions similar to those in Example 1 will be omitted for the sake of brevity.

[0097] like Figure 2B As shown, the optical system includes a lens barrel P0, a lens group housed within the lens barrel P0, and at least one spacer element. The lens group includes, from the object side to the image side, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, and a sixth lens E6. The at least one spacer element includes a first spacer element P1, a second spacer element P2, a third spacer element P3, a fourth spacer element P4, and a fifth spacer element P5.

[0098] The parameters such as the curvature radius, center thickness, and spacing distance between lenses and high-order coefficients of the optical system of this embodiment and Example 1 are the same, as shown in Table 1, Table 2-1, and Table 2-2. In addition, the number of spacing elements included in the optical system of this embodiment and Example 1 is also the same. The only difference is that the actual parameters of the lens barrel and each spacing element are different. For example, at least one of the parameters such as the lens barrel size, the thickness of the spacing element, the inner diameter of the spacing element, the outer diameter of the spacing element, and the spacing distance between the spacing elements is different. In other words, the main structure for imaging is the same, while the auxiliary structure for imaging is different. Therefore, the imaging quality of the optical system of Example 2 of the present application is as follows: Figures 3A to 3D shown.

[0099] Example 3

[0100] The following reference Figure 4A An optical system according to Example 3 of the present application is described.

[0101] like Figure 4A As shown, the optical system includes a lens barrel P0, a lens group housed within the lens barrel P0, and at least one spacer element. The lens group includes, from the object side to the image side, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, and a sixth lens E6. The at least one spacer element includes a first spacer element P1, a second spacer element P2, a third spacer element P3, a fourth spacer element P4, and a fifth spacer element P5.

[0102] The first lens E1 has positive focal power, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has positive focal power, with its object-side surface S3 being convex and its image-side surface S4 being convex. The third lens E3 has negative focal power, with its object-side surface S5 being concave and its image-side surface S6 being concave. The fourth lens E4 has negative focal power, with its object-side surface S7 being concave and its image-side surface S8 being concave. The fifth lens E5 has positive focal power, with its object-side surface S9 being convex and its image-side surface S10 being convex. The sixth lens E6 has negative focal power, with its object-side surface S11 being convex and its image-side surface S12 being concave. The optical system further includes a filter (not shown) disposed between the sixth lens E6 and the imaging surface S15.

[0103] Table 3 shows the basic parameters of the optical system of Example 3, wherein the units of curvature radius and thickness / distance are all millimeters (mm).

[0104]

[0105] Table 3

[0106] In Example 3, the object side surface and the image side surface of any lens from the first lens E1 to the sixth lens E6 are both aspherical surfaces, and the surface shape of each aspherical lens can be defined by the formula (1) given in the above Example 1. The following Tables 4-1 and 4-2 give the high-order coefficients A4, A6, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22, A23, A24, A25, A26, A27, A28, A29, A30, A31, A32, A33, A34, A35, A36, A37, A38, A39, A40, A41, A42, A43, A44, A45, A46, A47, A48, A49, 10 、A 12 、A 14 、A 16 、A 18 、A 20 、A 22 、A 24 、A 26 、A 28 and A 30 .

[0107]

[0108]

[0109] Table 4-1

[0110] Face number A18 A20 A22 A24 A26 A28 A30 S1 9.2776E-07 2.5090E-07 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S2 -3.6148E-07 -1.7048E-07 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S3 -1.3515E-06 7.3845E-08 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S4 -4.0099E-06 -9.8013E-07 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S5 -4.3099E-06 -8.4828E-07 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S6 5.4173E-06 2.3468E-06 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S7 -1.1093E-05 1.1182E-05 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S8 -2.0818E-06 1.6541E-05 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S9 1.2750E-04 -3.6538E-05 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S10 2.6452E-04 -2.5960E-04 -1.2828E-05 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S11 3.2144E-04 -2.2813E-04 -2.7864E-06 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S12 -6.9867E-04 -4.0411E-03 -2.7910E-04 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00

[0111] Table 4-2

[0112] Figure 5A The axial chromatic aberration curve of the optical system of Example 3 is shown, which indicates the deviation of the convergence point of light of different wavelengths after passing through the lens. Figure 5B The astigmatism curve of the optical system of Example 3 is shown, which indicates the meridional field curvature and the sagittal field curvature. Figure 5C The distortion curve of the optical system of Example 3 is shown, which represents the distortion magnitude values corresponding to different image heights. Figure 5D The chromatic aberration curve of the optical system of Example 3 is shown, which represents the deviation of different image heights on the imaging surface after the light passes through the lens. 5A to 5D It can be seen that the optical system provided in Example 3 can achieve good imaging quality.

[0113] Example 4

[0114] The following reference Figure 4B An optical system according to Example 4 of the present application is described.

[0115] like Figure 4B As shown, the optical system includes a lens barrel P0, a lens group housed within the lens barrel P0, and at least one spacer element. The lens group includes, from the object side to the image side, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, and a sixth lens E6. The at least one spacer element includes a first spacer element P1, a second spacer element P2, a third spacer element P3, a fourth spacer element P4, and a fifth spacer element P5.

[0116] The parameters such as the curvature radius, center thickness, and spacing distance between lenses and high-order coefficients of the optical systems of this embodiment and embodiment 3 are the same, as shown in Table 3, Table 4-1, and Table 4-2. In addition, the number of spacing elements included in the optical systems of this embodiment and embodiment 3 is also the same. The only difference is that the actual parameters of the lens barrel and each spacing element are different. For example, at least one of the parameters such as the lens barrel size, the thickness of the spacing element, the inner diameter of the spacing element, the outer diameter of the spacing element, and the spacing distance between the spacing elements is different. In other words, the main structure for imaging is the same, while the auxiliary structure for imaging is different. Therefore, the imaging quality of the optical system of embodiment 4 of the present application is as follows: 5A to 5D shown.

[0117] Example 5

[0118] The following reference Figure 6A An optical system according to Example 5 of the present application is described.

[0119] like Figure 6A As shown, the optical system includes a lens barrel P0, a lens group housed within the lens barrel P0, and at least one spacer element. The lens group includes, from the object side to the image side, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, and a sixth lens E6. The at least one spacer element includes a first spacer element P1, a second spacer element P2, a third spacer element P3, a fourth spacer element P4, and a fifth spacer element P5.

[0120] The first lens E1 has positive 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 concave. The third lens E3 has negative optical power, with its object-side surface S5 being convex and its image-side surface S6 being concave. The fourth lens E4 has negative optical power, with its object-side surface S7 being convex and its image-side surface S8 being concave. The fifth lens E5 has positive optical power, with its object-side surface S9 being convex and its image-side surface S10 being convex. The sixth lens E6 has negative optical power, with its object-side surface S11 being concave and its image-side surface S12 being concave.

[0121] Table 5 shows the basic parameters of the optical system of Example 5, wherein the units of curvature radius and thickness / distance are all millimeters (mm).

[0122]

[0123] Table 5

[0124] In Example 5, the object side surface and the image side surface of any lens from the first lens E1 to the sixth lens E6 are both aspherical surfaces, and the surface shape of each aspherical lens can be defined by the formula (1) given in the above Example 1. The following Tables 6-1 and 6-2 give the high-order coefficients A4, A6, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22, A23, A24, A25, A26, A27, A28, A29, A30, A31, A32, A33, A34, A35, A36, A37, A38, A39, A40, A41, A42, A43, A44, A45, A46, A47, A48, A49, 10 、A 12 、A 14 、A 16 、A 18 、A 20 、A 22 、A 24 、A 26 、A 28 and A 30 .

[0125] Face number A4 A6 A8 A10 A12 A14 A16 S1 -3.3588E-03 5.1271E-05 -1.5814E-05 2.3596E-06 -1.3251E-06 -1.9726E-06 -2.3515E-06 S2 -9.7238E-03 2.0055E-04 -5.8978E-05 8.9619E-06 5.1720E-06 3.7470E-06 2.2443E-07 S3 -5.8495E-03 4.7559E-04 -2.4883E-05 9.4975E-06 9.6299E-06 5.7337E-06 -6.9050E-09 S4 -2.6763E-03 1.4260E-03 1.0025E-04 7.5083E-06 2.7301E-05 3.3292E-05 4.3839E-06 S5 -1.3827E-02 1.0349E-03 -1.2324E-06 -7.2680E-06 3.3261E-05 4.2992E-05 3.6356E-06 S6 -8.3668E-03 1.9851E-03 -1.5115E-04 7.7439E-05 -1.2118E-05 2.2567E-05 -1.4620E-05 S7 -7.6855E-02 2.3180E-03 -2.1682E-03 1.4300E-04 -1.3811E-04 2.0899E-05 -1.3355E-05 S8 -1.6219E-01 3.1299E-02 -6.2624E-03 1.2102E-03 -6.3711E-04 1.6870E-04 -1.1056E-04 S9 -9.4676E-01 1.5273E-01 -3.8786E-02 7.4764E-03 -3.6745E-03 2.4471E-03 -1.8928E-03 S10 -3.5629E-01 2.5637E-02 -3.8879E-03 1.6264E-02 -9.6398E-03 4.8737E-03 -1.4075E-03 S11 -4.5540E-01 1.0128E-01 -8.1854E-02 4.2780E-02 -2.2722E-02 1.5096E-03 2.5998E-03 S12 -1.4726E+00 2.6377E-01 -5.6561E-02 2.9841E-02 -1.5203E-02 -5.1196E-04 2.2436E-03

[0126] Table 6-1

[0127] Face number A18 A20 A22 A24 A26 A28 A30 S1 -1.7992E-06 -6.4809E-07 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S2 -1.8817E-07 4.2000E-07 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S3 -1.6486E-06 -3.4413E-07 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S4 -3.3571E-06 -3.2241E-06 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S5 -4.7994E-06 -2.6868E-06 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S6 -5.5123E-06 -1.6145E-06 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S7 -1.1021E-06 1.2214E-06 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S8 2.2940E-05 8.0008E-07 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S9 9.5908E-04 -4.4346E-04 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S10 -2.0155E-04 7.9208E-05 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S11 -8.8018E-04 -3.6781E-04 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S12 2.0344E-04 -2.4035E-05 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00

[0128] Table 6-2

[0129] Figure 7A The axial chromatic aberration curve of the optical system of Example 5 is shown, which indicates the deviation of the convergence point of light of different wavelengths after passing through the lens. Figure 7B The astigmatism curve of the optical system of Example 5 is shown, which indicates the meridional field curvature and the sagittal field curvature. Figure 7C The distortion curve of the optical system of Example 5 is shown, which represents the distortion magnitude values corresponding to different image heights. Figure 7D The chromatic aberration curve of the optical system of Example 5 is shown, which represents the deviation of different image heights on the imaging surface after the light passes through the lens. 7A to 7D It can be seen that the optical system provided in Example 5 can achieve good imaging quality.

[0130] Example 6

[0131] The following reference Figure 6B An optical system according to Example 6 of the present application is described.

[0132] like Figure 6B As shown, the optical system includes a lens barrel P0, a lens group housed within the lens barrel P0, and at least one spacer element. The lens group includes, from the object side to the image side, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, and a sixth lens E6. The at least one spacer element includes a first spacer element P1, a second spacer element P2, a third spacer element P3, a fourth spacer element P4, and a fifth spacer element P5.

[0133] The parameters such as the curvature radius, center thickness, and spacing distance between lenses and higher-order coefficients of the optical systems of this embodiment and embodiment 5 are the same, as shown in Table 5, Table 6-1, and Table 6-2. In addition, the number of spacing elements included in the optical systems of this embodiment and embodiment 5 is also the same. The only difference is that the actual parameters of the lens barrel and each spacing element are different. For example, at least one of the parameters such as the lens barrel size, the thickness of the spacing element, the inner diameter of the spacing element, the outer diameter of the spacing element, and the spacing distance between the spacing elements is different. In other words, the main structure for imaging is the same, while the auxiliary structure for imaging is different. Therefore, the imaging quality of the optical system of embodiment 6 of the present application is as follows: 7A to 7D shown.

[0134] Example 7

[0135] The following reference Figure 8A An optical system according to Example 7 of the present application is described.

[0136] like Figure 8A As shown, the optical system includes a lens barrel P0, a lens group housed within the lens barrel P0, and at least one spacer element. The lens group includes, from the object side to the image side, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, and a sixth lens E6. The at least one spacer element includes a first spacer element P1, a second spacer element P2, a third spacer element P3, a fourth spacer element P4, and a fifth spacer element P5.

[0137] The first lens E1 has positive 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 negative optical power, with its object-side surface S5 being concave and its image-side surface S6 being concave. 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 convex. The sixth lens E6 has negative optical power, with its object-side surface S11 being concave and its image-side surface S12 being concave.

[0138] Table 7 shows the basic parameters of the optical system of Example 7, wherein the units of curvature radius and thickness / distance are all millimeters (mm).

[0139]

[0140]

[0141] Table 7

[0142] In Example 7, the object side surface and the image side surface of any lens from the first lens E1 to the sixth lens E6 are both aspherical surfaces, and the surface shape of each aspherical lens can be defined by the formula (1) given in the above-mentioned Example 1. The following Tables 8-1 and 8-2 give the high-order coefficients A4, A6, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22, A23, A24, A25, A26, A27, A28, A29, A30, A31, A32, A33, A34, A35, A36, A37, A38, A39, A40, A41, A42, A43, A44, A45, A46, A47, A48, A4 10 、A 12 、A 14 、A 16 、A 18 、A 20 、A 22 、A 24 、A 26 、A 28 and A 30 .

[0143] Face number A4 A6 A8 A10 A12 A14 A16 S1 -1.0862E-02 -1.0408E-03 -8.3885E-05 -1.2155E-05 -5.5028E-06 -3.7028E-06 -1.3555E-06 S2 -2.3912E-02 -3.8994E-04 3.3137E-04 -3.6395E-05 -1.5555E-05 -2.4389E-06 -6.8906E-07 S3 -5.3613E-03 1.4102E-03 4.7062E-04 -6.1185E-05 -2.1406E-05 -2.5135E-06 -1.4886E-07 S4 7.0726E-03 1.1998E-03 1.6857E-04 -5.7538E-05 1.3146E-05 -3.2690E-06 -1.2142E-06 S5 -1.9052E-02 3.0830E-05 -2.0923E-05 -8.0402E-05 1.8846E-05 -4.4782E-06 -1.4131E-06 S6 -2.7660E-02 4.0632E-03 -2.2144E-04 1.0474E-04 3.6758E-05 -2.2664E-05 -1.5635E-06 S7 -5.5805E-02 9.0449E-03 -2.2056E-03 -8.6405E-04 -1.2323E-04 1.9226E-04 8.0303E-05 S8 -2.1830E-01 4.2208E-02 -5.2408E-03 -1.1378E-03 -7.0088E-04 5.1988E-04 1.2670E-04 S9 -8.0388E-01 1.6632E-01 -3.6263E-02 1.0514E-02 -4.3181E-03 1.7439E-03 5.7155E-05 S10 4.5394E-01 -8.0407E-02 1.4637E-02 1.1709E-02 -2.1463E-03 -1.6230E-04 -9.8485E-04 S11 1.4304E-01 5.7681E-02 -3.0828E-02 2.0231E-03 -5.9880E-03 -2.2057E-03 4.6156E-04 S12 -1.0257E+00 1.5054E-01 -1.1217E-02 1.0016E-03 -7.9872E-03 -3.4302E-03 -4.6790E-04

[0144] Table 8-1

[0145] Face number A18 A20 A22 A24 A26 A28 A30 S1 -1.6656E-07 3.5711E-07 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S2 4.5219E-07 3.3098E-07 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S3 7.3246E-07 3.3940E-07 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S4 -6.2749E-07 4.5644E-07 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S5 -2.6704E-07 6.7838E-07 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S6 1.4639E-06 -1.2402E-06 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S7 2.8941E-05 1.0795E-05 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S8 4.9513E-05 1.4247E-05 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S9 6.1316E-04 -9.2035E-04 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S10 3.0387E-04 1.1368E-05 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S11 1.9724E-04 -2.3881E-04 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S12 1.5197E-04 3.4539E-04 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00

[0146] Table 8-2

[0147] Figure 9A The axial chromatic aberration curve of the optical system of Example 7 is shown, which indicates the deviation of the convergence point of light of different wavelengths after passing through the lens. Figure 9B The astigmatism curve of the optical system of Example 7 is shown, which indicates the meridional field curvature and the sagittal field curvature. Figure 9C The distortion curve of the optical system of Example 7 is shown, which represents the distortion magnitude values corresponding to different image heights. Figure 9D The magnification chromatic aberration curve of the optical system of Example 7 is shown, which represents the deviation of different image heights on the imaging surface after the light passes through the lens. 9A to 9D It can be seen that the optical system provided in Example 7 can achieve good imaging quality.

[0148] Example 8

[0149] The following reference Figure 8B An optical system according to Example 8 of the present application is described.

[0150] like Figure 8B As shown, the optical system includes a lens barrel P0, a lens group housed within the lens barrel P0, and at least one spacer element. The lens group includes, from the object side to the image side, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, and a sixth lens E6. At least the spacer elements include a first spacer element P1, a second spacer element P2, a third spacer element P3, a fourth spacer element P4, and a fifth spacer element P5.

[0151] The parameters such as the curvature radius, center thickness, and spacing distance between lenses of the optical system of this embodiment and Example 7 are the same as those of Example 7, as shown in Table 7, Table 8-1, and Table 8-2. In addition, the number of spacing elements included in the optical system of this embodiment and Example 7 is also the same. The only difference is that the actual parameters of the lens barrel and each spacing element are different. For example, at least one of the parameters such as the lens barrel size, the thickness of the spacing element, the inner diameter of the spacing element, the outer diameter of the spacing element, and the spacing distance between the spacing elements is different. In other words, the main structure for imaging is the same, while the auxiliary structure for imaging is different. Therefore, the imaging quality of the optical system of Example 8 of the present application is as follows: 9A to 9D shown.

[0152] Table 9 below shows the effective focal length values of the lenses in the optical systems of Examples 1 to 8, where the unit of the effective focal length values is millimeter (mm).

[0153] Parameter Value / Example 1 2 3 4 5 6 7 8 f1 4.67 4.67 4.09 4.09 62.91 62.91 5.07 5.07 f2 2.88 2.88 2.71 2.71 2.49 2.49 2.99 2.99 f3 -2.38 -2.38 -1.83 -1.83 -4.47 -4.47 -2.95 -2.95 f4 -5.00 -5.00 -3.61 -3.61 -16.26 -16.26 -10.75 -10.75 f5 2.35 2.35 1.69 1.69 3.80 3.80 3.15 3.15 f6 -2.77 -2.77 -2.55 -2.55 -3.37 -3.37 -2.46 -2.46

[0154] Table 9

[0155] Table 10 below shows some basic parameters of the lens barrels and spacer elements of the optical systems of Examples 1 to 8, such as d1m, D1s, d2m, d3s, d4s, D4m, d5m, d0m, CP2, CP3, CP4, CP5, EP01, EP12, EP23, EP34, and EP45. The units of the basic parameters listed in Table 10 are all millimeters (mm).

[0156]

[0157]

[0158] Table 10 In summary, in Examples 1 to 8, the optical systems respectively meet the conditions in the following Table 11.

[0159] Conditional formula / Example 1 2 3 4 5 6 7 8 d0m / R12 2.10 2.10 4.91 4.91 0.97 0.97 0.65 0.65 (CT2+CP2) / CT3 1.37 1.37 1.36 1.36 1.71 1.71 1.53 1.53 f2 / (EP12+EP23) 3.23 3.22 2.88 2.95 3.39 3.53 4.15 4.15 (EP01+CT1) / T12 33.73 33.65 12.70 12.97 11.59 12.08 34.52 34.52 f3 / (T34+CP3) -5.03 -4.62 -2.38 -2.38 -17.42 -16.67 -8.35 -8.35 (CT4+T45) / EP34 1.30 1.38 0.85 0.85 1.69 1.86 1.67 1.67 (CP4+EP45) / CT5 1.53 1.53 0.99 0.99 1.35 1.38 1.35 1.41 R1 / D1s 0.71 0.46 0.77 0.49 0.52 0.34 0.47 0.47 R3 / d1m 3.00 3.00 2.94 2.91 1.17 0.75 2.48 2.48 (R4-R5) / d2m 3.36 4.68 2.63 2.63 2.23 2.92 5.13 5.13 V3 30.00 30.00 33.60 33.60 21.50 21.50 29.20 29.20 R6 / d3s 1.17 1.13 0.83 0.83 1.75 1.70 1.59 1.59 V4 33.00 33.00 42.20 42.20 23.70 23.70 32.70 32.70 |R8 / d4s| 6.52 6.52 1.63 1.41 3.47 4.55 4.47 5.92 R9 / D4m 0.60 0.59 0.43 0.45 0.61 0.61 0.84 0.82 f6 / (CT6+T56+CP5) -3.40 -3.40 -2.74 -2.74 -4.40 -4.40 -2.69 -2.66 |R11 / d5m| 1.95 1.95 1.16 1.38 1.09 1.09 0.63 0.62

[0160] Table 11

[0161] Table 12-1 below shows the structural sensitivity of the air gap between the second and third lenses for three optical system samples. Specifically, Table 12-1 shows the changes in the center and edge of the second and third lenses relative to their design values (i.e., center point displacement and edge point displacement), as well as the structural sensitivity ΔSP2 of the air gap between the second and third lenses on the optical axis (i.e., the change in the gap between the center region of the second and third lenses) when the same load is applied to the three optical system samples. The units of center point displacement, edge point displacement, and ΔSp2 in Table 12-1 are all micrometers (μm).

[0162] More specifically, applying the same load to the structural regions (i.e., the non-effective diameter portions) of Samples 1, 2, and 3 of the optical system will cause a deformation as the force is transferred from the edge to the center of the structural region. For example, the structural regions of the image-side surfaces of the third lenses of Samples 1, 2, and 3 are each subjected to the same external force. Under the influence of the stress, both the edge and center positions of the second and third lenses deform, thereby causing the air gap between the second and third lenses to change. For example, referring to Table 12-1, through simulation, the structural sensitivities ΔSP2 of Samples 1, 2, and 3 of the optical system are 0.277μm, 0.918μm, and 2.3032μm, respectively. It can be seen that Sample 1 of the optical system experiences a smaller displacement and has a better structural sensitivity.

[0163]

[0164] Table 12-1

[0165] The following Table 12-2 shows the optical sensitivity and comprehensive sensitivity of the spatial gap between the second lens and the third lens in the above three samples of the optical system. Specifically, Table 12-2 shows the change in the MTF (Modulation Transfer Function) peak of the edge field of view (1.0F) when the spatial interval between the second lens and the third lens on the optical axis of the three samples of the optical system changes by +1μm and -1μm. That is, the optical sensitivity can represent the change in the MTF peak of the edge field of view of the optical system when the displacement of the lens is constant (i.e., the drop situation). In Table 12-2, the symbols "+" and "-" in +1μm and -1μm indicate the fluctuation direction of the spatial interval between the two adjacent lenses compared to the design value. The MTF peak is in percentage (%).

[0166] Referring to Table 12-2, simulations show that for every +1μm change in the spacing between the second and third lenses on the optical axis, the peak MTF values for the edge field of view for optical systems Samples 1, 2, and 3 change by -0.3%, -0.9%, and -1.1%, respectively. For every -1μm change in the spacing between the second and third lenses on the optical axis, the peak MTF values for the edge field of view for optical systems Samples 1, 2, and 3 change by 0%, -0.5%, and -0.2%, respectively. These comparisons indicate that the peak MTF value for optical system Sample 1 is less affected by stress deformation, resulting in superior optical sensitivity.

[0167]

[0168] Table 12-2

[0169] Furthermore, the combined sensitivity of the three optical system samples is -0.0831μm, -0.8263μm, and -2.53352μm, respectively. This combined sensitivity indicates how much deformation affects the MTF peak. The comparison results show that optical system sample 1 experiences minimal deformation under stress, and this deformation has a minimal effect on MTF. Its combined sensitivity is significantly better than samples 2 and 3, and it exhibits greater stability.

[0170] The experimental comparison of different optical system samples above reveals that when the optical system satisfies the numerical ranges of the conditions 1.36≤(CT2+CP2) / CT3≤1.71 and 2.88≤f2 / (EP12+EP23)≤4.15, the center and edge displacements of the second and third lenses are smaller, the MTF peak is less affected by changes in the air gap between the lenses, and the assembly stability is higher. Therefore, by rationally controlling the numerical ranges of the above parameter conditions, so that the optical system simultaneously satisfies the conditions 1.36≤(CT2+CP2) / CT3≤1.71 and 2.88≤f2 / (EP12+EP23)≤4.15, the overall sensitivity and stability of the optical system can be improved.

[0171] The above description is merely a preferred embodiment of the present application and an illustration of the technical principles employed. Those skilled in the art should understand that the scope of the utility model disclosed herein is not limited to the technical solutions formed by the specific combination of the above-mentioned technical features, but also encompasses other technical solutions formed by any combination of the above-mentioned technical features or their equivalents without departing from the concept of the utility model. For example, a technical solution formed by replacing the above-mentioned features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. An optical system, characterized in that The invention comprises a lens barrel having an accommodation space, a lens group and at least one spacer element accommodated in the lens barrel, The lens group includes: a first lens having positive optical power, a second lens having positive optical power, a third lens having negative optical power, a fourth lens having negative optical power, a fifth lens having positive optical power, and a sixth lens having negative optical power, which are arranged in sequence from the object side to the image side along the optical axis; The at least one spacer element includes: a first spacer element located between the first lens and the second lens and in direct contact with the image side of the first lens; a second spacer element located between the second lens and the third lens and in direct contact with the image side of the second lens; and a third spacer element located between the third lens and the fourth lens and in direct contact with the image side of the third lens. wherein the number of lenses having optical power in the lens group is six; The center thickness CT2 of the second lens on the optical axis, the center thickness CT3 of the third lens on the optical axis, and the maximum thickness CP2 of the second spacer element satisfy the following: 1.36≤(CT2+CP2) / CT3≤1.71; The effective focal length f2 of the second lens, the interval EP12 between the first and second spacer elements, and the interval EP23 between the second and third spacer elements satisfy: 2.88≤f2 / (EP12+EP23)≤4.

15.

2. The optical system according to claim 1, wherein An inner diameter d0m of the rear end surface of the lens barrel closest to the imaging surface and a curvature radius R12 of the image-side surface of the sixth lens satisfy the following relationship: 0.65≤d0m / R12≤4.

91.

3. The optical system according to claim 1, wherein: The interval EP01 between the front end surface of the lens barrel and the first spacer element, the center thickness CT1 of the first lens on the optical axis, and the air interval T12 between the first lens and the second lens on the optical axis satisfy: 11.59≤(EP01+CT1) / T12≤34.

52.

4. The optical system according to claim 1, wherein: An air gap T34 between the third lens and the fourth lens on the optical axis, an effective focal length f3 of the third lens, and a maximum thickness CP3 of the third spacer element satisfy the following: -17.42≤f3 / (T34+CP3)≤-2.

38.

5. The optical system according to claim 1, wherein The at least one spacer element further includes a fourth spacer element located between the fourth lens and the fifth lens and in direct contact with the image side of the fourth lens, A center thickness CT4 of the fourth lens on the optical axis, an air gap T45 between the fourth lens and the fifth lens on the optical axis, and an interval EP34 between the third spacer element and the fourth spacer element satisfy: 0.85≤(CT4+T45) / EP34≤1.

86.

6. The optical system according to claim 1, wherein: The at least one spacer element further includes a fourth spacer element located between the fourth lens and the fifth lens and in direct contact with the image side of the fourth lens, and a fifth spacer element located between the fifth lens and the sixth lens and in direct contact with the image side of the fifth lens, The maximum thickness CP4 of the fourth spacer element, the interval EP45 between the fourth spacer element and the fifth spacer element, and the center thickness CT5 of the fifth lens on the optical axis satisfy: 0.99≤(CP4+EP45) / CT5≤1.

53.

7. The optical system according to claim 1, wherein: A curvature radius R1 of the object-side surface of the first lens and an outer diameter D1s of the object-side surface of the first spacer element satisfy the following: 0.34≤R1 / D1s≤0.

77.

8. The optical system according to claim 1, wherein: A curvature radius R3 of the object-side surface of the second lens and an inner diameter d1m of the image-side surface of the first spacer element satisfy the following: 0.75≤R3 / d1m≤3.

00.

9. The optical system according to claim 1, wherein: A curvature radius R4 of the image-side surface of the second lens, a curvature radius R5 of the object-side surface of the third lens, and an inner diameter d2m of the image-side surface of the second spacer element satisfy: 2.23≤(R4-R5) / d2m≤5.

13.

10. The optical system according to claim 1, wherein: The Abbe number V3 of the third lens satisfies: 21.5≤V3<34; the curvature radius R6 of the image-side surface of the third lens and the inner diameter d3s of the object-side surface of the third spacer element satisfy: 0.83≤R6 / d3s≤1.

75.

11. The optical system according to claim 1, wherein: The at least one spacer element further includes a fourth spacer element located between the fourth lens and the fifth lens and in direct contact with the image side of the fourth lens, The Abbe number V4 of the fourth lens satisfies: 23.7≤V4≤42.2; the curvature radius R8 of the image-side surface of the fourth lens and the inner diameter d4s of the object-side surface of the fourth spacer element satisfy: 1.41≤|R8 / d4s|≤6.

52.

12. The optical system according to claim 1, wherein: The at least one spacer element further includes a fourth spacer element located between the fourth lens and the fifth lens and in direct contact with the image side of the fourth lens, A curvature radius R9 of the object-side surface of the fifth lens and an outer diameter D4m of the image-side surface of the fourth spacer element satisfy the following: 0.43≤R9 / D4m≤0.

84.

13. The optical system according to claim 1, wherein: The at least one spacer element further includes a fifth spacer element located between the fifth lens and the sixth lens and in direct contact with the image side of the fifth lens, The effective focal length f6 of the sixth lens, the center thickness CT6 of the sixth lens on the optical axis, the air gap T56 between the fifth lens and the sixth lens on the optical axis, and the maximum thickness CP5 of the fifth spacer element satisfy: -4.4≤f6 / (CT6+T56+CP5)≤-2.

66.

14. The optical system according to claim 1, wherein: The at least one spacer element further includes a fifth spacer element located between the fifth lens and the sixth lens and in direct contact with the image side of the fifth lens, A curvature radius R11 of the object-side surface of the sixth lens and an inner diameter d5m of the image-side surface of the fifth spacer element satisfy the following: 0.62≤|R11 / d5m|≤1.

95.

15. The optical system according to claim 1, wherein: The object side surface of the first lens is convex, and the image side surface is concave; The object side surface of the second lens is convex; The image side surface of the third lens is concave; The object-side surface of the fifth lens is convex, and the image-side surface is convex; The image-side surface of the sixth lens is concave.

Images