Optical system

Abstract

The utility model provides an optical system. The optical system comprises a lens barrel, a lens group and at least one spacer, and the lens group and the spacer are arranged in the lens barrel. The five lenses are sequentially a first lens with negative focal power, a second lens with positive focal power, a third lens with focal power, a fourth lens with focal power and a fifth lens with focal power from the object side to the image side; eP01 / CT1 is greater than or equal to 1.92 and less than or equal to 3.08; and (EP2 + T23) / CT3 is greater than or equal to 1.04 and less than or equal to 2.86. According to the utility model, the problem that a five-piece optical system in the prior art meets the optical performance requirement by constraining the size of a front-end lens, so that the assembly stability is poor, and the defocus curve deviates is solved.

Description

TECHNICAL FIELD

[0001] The utility model relates to optical imaging equipment technical field, specifically, relate to an optical system. BACKGROUND

[0002] In the design and application of modern optical system, five-piece optical system is widely used in mobile phone lens, miniature camera and other equipment because of its compact structure, excellent imaging performance and other advantages.

[0003] However, the five-piece optical system in the prior art faces many challenges in the process of design and manufacture. In order to meet the demand of optical performance, the size of the front lens is usually constrained. Although this design can optimize the optical performance to a certain extent, it is easy to affect the assembly stability of the front lens and the front and rear elements in the lens barrel due to the size and surface shape of the front lens, and poor assembly stability can easily lead to optical system misalignment, which in turn can easily lead to the shift of defocus curve, resulting in poor optical performance of the optical system.

[0004] That is, the five-piece optical system in the prior art has the problem of poor assembly stability caused by constraining the size of the front lens to meet the demand of optical performance, which in turn leads to the shift of defocus curve. UTILITY MODEL CONTENTS

[0005] The main purpose of the utility model is to provide an optical system to solve the problem of poor assembly stability caused by constraining the size of the front lens to meet the demand of optical performance in the five-piece optical system in the prior art, which in turn leads to the shift of defocus curve.

[0006] In order to achieve the above object, according to one aspect of the present application, an optical system is provided, comprising a lens barrel and a lens group and at least one spacer arranged in the lens barrel, the lens group is composed of five lenses, the five lenses are in order from the object side to the image side a first lens with negative refractive power, a second lens with positive refractive power, a third lens with refractive power, a fourth lens with refractive power and a fifth lens with refractive power, the object side surface of the first lens is concave, the image side surface of the second lens is convex, and the object side surface of the third lens is concave; the at least one spacer comprises a first spacer arranged between the first lens and the second lens and partially in contact with the image side surface of the first lens, a second spacer arranged between the second lens and the third lens and partially in contact with the image side surface of the second lens, and a third spacer arranged between the third lens and the fourth lens and partially in contact with the image side surface of the third lens; the axial interval EP01 between the object side end surface of the lens barrel and the first spacer and the central thickness CT1 of the first lens on the optical axis of the optical system satisfy: 1.92≤EP01 / CT1≤3.08; the air interval T23 of the second lens and the third lens on the optical axis, the axial interval EP23 between the second spacer and the third spacer and the central thickness CT3 of the third lens on the optical axis satisfy: 1.04≤(EP23+T23) / CT3≤2.86.

[0007] According to another aspect of the present application, an optical system is provided, comprising a lens barrel and a lens group and at least one spacer arranged in the lens barrel, the lens group is composed of five lenses, the five lenses are in order from the object side to the image side a first lens with negative refractive power, a second lens with positive refractive power, a third lens with refractive power, a fourth lens with refractive power and a fifth lens with refractive power, the object side surface of the first lens is concave, the image side surface of the second lens is convex, and the object side surface of the third lens is concave; the at least one spacer comprises a first spacer arranged between the first lens and the second lens and partially in contact with the image side surface of the first lens, a second spacer arranged between the second lens and the third lens and partially in contact with the image side surface of the second lens, and a third spacer arranged between the third lens and the fourth lens and partially in contact with the image side surface of the third lens; the axial interval EP01 between the object side end surface of the lens barrel and the first spacer and the central thickness CT1 of the first lens on the optical axis of the optical system satisfy: 1.92≤EP01 / CT1≤3.08; the inner diameter d0s of the object side end surface of the lens barrel and the curvature radius R1 of the object side surface of the first lens satisfy: -3.21≤d0s / R1≤-1.15.

[0008] According to another aspect of the utility model, an optical system is provided, including lens barrel and lens group and at least one spacer set in lens barrel, the lens group is composed of five lenses, five lenses are in order from object side to image side first lens with negative focal power, second lens with positive focal power, third lens with focal power, fourth lens with focal power and fifth lens with focal power, the object side surface of first lens is concave, the image side surface of second lens is convex, the object side surface of third lens is concave, at least one spacer includes the first spacer between first lens and second lens and with the image side surface of first lens partial contact, the second spacer between second lens and third lens and with the image side surface of second lens partial contact, the effective focal length f1 of first lens and the central thickness CT1 of first lens on optical axis satisfy :-25.35 <= f1 / CT1 <=-1.49, the outer diameter D2s of the object side surface of second spacer, the inner diameter d2s of the object side surface of second spacer and the curvature radius R2 of the image side surface of first lens satisfy :-0.79 <= (D2s-d2s) / R2 <=4.67.

[0009] Further, the maximum axial thickness CP1 of first spacer, the air interval T12 of first lens and second lens on optical axis and the central thickness CT1 of first lens on optical axis satisfy :0.98 <= (CP1+T12) / CT1 <=4.80.

[0010] Further, the effective focal length f2 of second lens and the axial interval EP12 between first spacer and second spacer satisfy :1.82 <= f2 / EP12 <=4.46.

[0011] Further, the inner diameter d0s of the object side surface of lens barrel and the curvature radius R1 of the object side surface of first lens satisfy :-3.21 <= d0s / R1 <=-1.15.

[0012] Further, the curvature radius R3 of the object side surface of second lens, the refractive index N2 of second lens and the outer diameter D2s of the object side surface of second spacer satisfy :0.39 <= |R3*N2| / D2s <=1.17.

[0013] Further, the curvature radius R4 of the image side surface of second lens and the inner diameter d2s of the object side surface of second spacer satisfy :-4.78 <= R4 / d2s <=-0.59.

[0014] Further, at least one spacer still includes the fourth spacer between fourth lens and fifth lens, the axial interval EP34 between third spacer and fourth spacer and the central thickness CT4 of fourth lens on optical axis satisfy :0.54 <= CT4 / EP34 <=1.76.

[0015] Further, an air interval T34 of the third lens and the fourth lens on the optical axis satisfies: 0.11≤T34 / CP3≤4.55.

[0016] Further, a curvature radius R5 of the object side surface of the third lens satisfies: -5.32≤R5 / d3s≤-0.36.

[0017] Further, an outer diameter D3s of the object side surface of the third spacer satisfies: 1.69≤|D3s / R6|≤4.33.

[0018] Further, the at least one spacer further comprises a fourth spacer disposed between the fourth lens and a fifth lens, an object side surface of the fifth lens is convex, and an outer diameter D4m of an image side surface of the fourth spacer satisfies: 1.28≤D4m / R9≤4.34.

[0019] By applying the technical scheme of the present application, the optical system of the present application is composed of a lens barrel, five lenses and multiple spacers arranged in the lens barrel. By reasonably arranging the focal power and surface shape of the five lenses, the positions of the first spacer, the second spacer and the third spacer, and by setting the optical system to satisfy -1.92≤EP01 / CT1≤3.08, the edge thickness of the first lens is controlled, and the center thickness of the first lens is limited to meet the performance requirements. However, in the case of controlling the edge thickness and the center thickness of the first lens, the optical system is easily affected by the center thickness and the surface shape of the first lens, which leads to the assembly deviation. Therefore, the present application limits 1.04≤(EP23+T23) / CT3≤2.86, optimizes the air interval of the second lens and the third lens in the optical system, the edge thickness of the second lens, the center thickness of the third lens and other factors, ensures the assembly stability of the front-end second lens and the third lens, reduces the sensitivity of the optical performance, ensures that the final optical system has a small risk of defocus curve deviation, reduces the risk of defocus curve deviation after assembly, and thus ensures the optical performance of the final optical system. BRIEF DESCRIPTION OF DRAWINGS

[0020] The drawings constituting a part of the specification of the present application are used to provide a further understanding of the present application, and the schematic embodiments of the present application and the explanations thereof are used to explain the present application, and do not constitute an improper limitation on the present application. In the drawings:

[0021] Figure 1A size marking drawing of the optical system of one optional embodiment of the utility model is shown;

[0022] Figure 2 A structure schematic view of the optical system of embodiment 1-1 of the utility model is shown;

[0023] Figure 3 A structure schematic view of the optical system of embodiment 1-2 of the utility model is shown;

[0024] Figure 4 A structure schematic view of the optical system of embodiment 1-3 of the utility model is shown;

[0025] Figures 5 to 8 The on-axis chromatic aberration curve, astigmatism curve, distortion curve and magnification chromatic aberration curve of the optical system of embodiment one of the utility model are shown respectively;

[0026] Figure 9 A structure schematic view of the optical system of embodiment 2-1 of the utility model is shown;

[0027] Figure 10 A structure schematic view of the optical system of embodiment 2-2 of the utility model is shown;

[0028] Figure 11 A structure schematic view of the optical system of embodiment 2-3 of the utility model is shown;

[0029] Figures 12 to 15 The on-axis chromatic aberration curve, astigmatism curve, distortion curve and magnification chromatic aberration curve of the optical system of embodiment two of the utility model are shown respectively;

[0030] Figure 16 A structure schematic view of the optical system of embodiment 3-1 of the utility model is shown;

[0031] Figure 17 A structure schematic view of the optical system of embodiment 3-2 of the utility model is shown;

[0032] Figure 18 A structure schematic view of the optical system of embodiment 3-3 of the utility model is shown;

[0033] Figures 19 to 22 The on-axis chromatic aberration curve, astigmatism curve, distortion curve and magnification chromatic aberration curve of the optical system of embodiment three of the utility model are shown respectively;

[0034] Figure 23 A defocus curve schematic view of the optical system of one optional example of the utility model when EP01 / CT1=2.42 and (EP23+T23) / CT3=1.90 is shown;

[0035] Figure 24 A schematic diagram of the through focus curve of an optical system of one optional example satisfying EP01 / CT1 = 2.42 and (EP23+T23) / CT3 = 0.98 is shown;

[0036] Figure 25 A schematic diagram of the through focus curve of an optical system of another optional example satisfying EP01 / CT1 = 2.42 and (EP23+T23) / CT3 = 2.94 is shown.

[0037] Wherein, the above drawings include the following reference signs:

[0038] P0, lens barrel; E1, first lens; S1, object side surface of the first lens; S2, image side surface of the first lens; E2, second lens; S3, object side surface of the second lens; S4, image side surface of the second lens; E3, third lens; S5, object side surface of the third lens; S6, image side surface of the third lens; E4, fourth lens; S7, object side surface of the fourth lens; S8, image side surface of the fourth lens; E5, fifth lens; S9, object side surface of the fifth lens; S10, image side surface of the fifth lens; P1, first spacer; P2, second spacer; P3, third spacer; P4, fourth spacer. DETAILED DESCRIPTION

[0039] It should be noted that the embodiments and features in the embodiments in the present application can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0040] It should be noted that, unless otherwise specified, all technical and scientific terms used in the present application have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0041] In the present application, unless otherwise specified, the orientation words such as "upper", "lower", "top", "bottom" are generally directed to the directions shown in the drawings, or are directed to the vertical, perpendicular or gravity directions of the components themselves; similarly, for the convenience of understanding and description, "inner" and "outer" refer to the inner and outer relative to the contour of each component itself, but the above orientation words are not used to limit the present application.

[0042] It should be noted that in the present specification, the expressions of first, second, third, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the features. Therefore, the first lens discussed below can also be referred to as the second lens or the third lens without departing from the teachings of the present application.

[0043] In the drawings, the thickness, size, and shape of the lenses have been exaggerated slightly for ease of explanation. Specifically, the shape of the spherical or aspherical surface shown in the drawings is shown by way of example. That is, the shape of the spherical or aspherical surface is not limited to the shape of the spherical or aspherical surface shown in the drawings. The drawings are merely examples and are not strictly drawn to scale.

[0044] In this document, the paraxial region refers to a region near the optical axis. If the lens surface is convex and the position of the convex surface is not defined, it means that the lens surface is convex at least in the paraxial region. If the lens surface is concave and the position of the concave surface is not defined, it means that the lens surface is concave at least in the paraxial region. The judgment of the surface shape in the paraxial region can be made according to the judgment method of those skilled in the art, with the R value (R refers to the radius of curvature in the paraxial region, usually refers to the R value on the lens data in the optical software) positive or negative judgment of convex or concave. In terms of the object side surface, when the R value is positive, it is determined to be convex, and when the R value is negative, it is determined to be concave. In terms of the image side surface, when the R value is positive, it is determined to be concave, and when the R value is negative, it is determined to be convex. In this application, the left side is the object side, and the right side is the image side.

[0045] In order to solve the problem that the five-piece optical system in the prior art has poor assembly stability due to the constraint of the size of the front end lens to meet the optical performance requirements, thereby causing the defocus curve to deviate, the utility model provides an optical system.

[0046] As shown in Figures 1 to 25 In an optional embodiment of the present application, the optical system includes a lens barrel, a lens group arranged in the lens barrel, and at least one spacer, the lens group is composed of five lenses, the five lenses are sequentially a first lens with negative optical power, a second lens with positive optical power, a third lens with optical power, a fourth lens with optical power, and a fifth lens with optical power from the object side to the image side, the object side surface of the first lens is concave, the image side surface of the second lens is convex, and the object side surface of the third lens is concave; the at least one spacer includes a first spacer arranged between the first lens and the second lens and partially in contact with the image side surface of the first lens, a second spacer arranged between the second lens and the third lens and partially in contact with the image side surface of the second lens, and a third spacer arranged between the third lens and the fourth lens and partially in contact with the image side surface of the third lens; the axial interval EP01 between the object side end surface of the lens barrel and the first spacer and the central thickness CT1 of the first lens on the optical axis of the optical system satisfy: 1.92≤EP01 / CT1≤3.08; the air interval T23 of the second lens and the third lens on the optical axis, the axial interval EP23 between the second spacer and the third spacer, and the central thickness CT3 of the third lens on the optical axis satisfy: 1.04≤(EP23+T23) / CT3≤2.86.

[0047] The optical system of the present application is composed of a lens barrel and five lenses and a plurality of spacers arranged in the lens barrel. By reasonably arranging the power and surface shape of the five lenses, the positions of the first, second and third spacers, and setting the optical system to satisfy -1.92≤EP01 / CT1≤3.08, the edge thickness of the first lens is controlled while the central thickness of the first lens is limited to meet the performance requirements. However, in the case of controlling the edge thickness and central thickness of the first lens, the optical system is easily affected by the central thickness and surface shape of the first lens, etc., leading to assembly deviation, resulting in poor assembly stability, and further causing the defocus curve of the assembled optical system to deviate, affecting the optical performance of the optical system. Therefore, by restricting 1.04≤(EP23+T23) / CT3≤2.86, the air gap of the second and third lenses, the edge thickness of the second lens, the central thickness of the third lens, etc. in the optical system are optimized to ensure the assembly stability of the front-end second and third lenses, reduce the sensitivity of the optical performance, and ensure that the final optical system is less likely to be affected by the defocus curve deviation, reducing the risk of defocus curve deviation after assembly, thereby ensuring the optical performance of the final optical system.

[0048] In addition, referring to Table 1, Figures 23 to 25 shown below, under the premise that the optical system satisfies -1.92≤EP01 / CT1≤3.08, Figure 23 the defocus curve of the optical system satisfying EP01 / CT1=2.42 and (EP23+T23) / CT3=1.90 is shown, Figure 24 the defocus curve of the optical system satisfying EP01 / CT1=2.42 and (EP23+T23) / CT3=0.98 is shown, Figure 25 the defocus curve of the optical system satisfying EP01 / CT1=2.42 and (EP23+T23) / CT3=2.94 is shown.

[0049] from Figures 23 to 25It can be seen that when the optical system satisfies EP01 / CT1 = 2.42 and (EP23+T23) / CT3 = 1.90, the defocus curves of each field of view of the optical system do not shift, and the imaging quality is good. When the optical system satisfies EP01 / CT1 = 2.42 and (EP23+T23) / CT3 = 0.98, the peak of the defocus curve of part of the field of view decreases and the center of the defocus curve shifts, resulting in that part of the field of view of the optical system has no optical performance, and finally it is manifested as the situation that part of the field of view is not imaged or the imaging is not clear. When the optical system satisfies EP01 / CT1 = 2.42 and (EP23+T23) / CT3 = 2.94, the peak of the defocus curve of part of the field of view decreases, and the center of the defocus curve of part of the field of view shifts, resulting in that part of the field of view has no optical performance, and finally it is manifested as the situation that part of the field of view is not imaged or the imaging is not clear. It can be seen that when-1.92≤EP01 / CT1≤3.08 and (EP23+T23) / CT3 is controlled in the range of 1.04 to 2.86, the air gap of the second lens and the third lens, the edge thickness of the second lens, the center thickness of the third lens and other factors in the optical system can be optimized, the assembly stability of the front-end second lens and the third lens is ensured, the optical performance sensitivity is reduced, the risk of the final optical system being affected by the defocus curve shift is small, the risk of the defocus curve shift after assembly is reduced, and thus the optical performance of the final optical system is ensured.

[0050] Table 1

[0051] Example 1 Example 2 Example 3 Condition (EP23+T23) / CT3 = 1.90 (EP23+T23) / CT3 = 0.98 (EP23+T23) / CT3 = 2.94 Defocus curve Figure 23 Figure 24 Figure 25

[0052] In the embodiment, the at least one spacer further comprises a fourth spacer disposed between the fourth lens and the fifth lens and in contact with the image side surface portion of the fourth lens.

[0053] In the embodiment, the maximum axial thickness CP1 of the first spacer, the air gap T12 of the first lens and the second lens on the optical axis, and the center thickness CT1 of the first lens on the optical axis satisfy: 0.98≤(CP1+T12) / CT1≤4.80. By restricting the expression, the stray light improvement space between the first lens and the second lens can be ensured. Due to the limitation of the structure of the optical system, the flange position of the image side surface of the first lens will generate more reflected stray light. The expression can ensure that the stray light path can be effectively intercepted by the first spacer, thereby ensuring the imaging quality. The center thickness of the first lens is limited, and at the same time the structure of the first lens can generate less stray light reflection path.

[0054] In the present embodiment, the effective focal length f2 of the second lens and the axial interval EP12 between the first spacer and the second spacer satisfy: 1.82≤f2 / EP12≤4.46. Through the expression, the accurate transmission path of the light rays through the second lens is thus ensured, while the edge thickness of the second lens is limited through the above expression, and the thickness of the second lens is ensured to be stable.

[0055] In the present embodiment, the inner diameter d0s of the object side end surface of the lens barrel and the radius of curvature R1 of the object side surface of the first lens satisfy: -3.21≤d0s / R1≤-1.15. Through the expression, by restricting the range of the ratio between the inner diameter of the object side end surface of the lens barrel and the radius of curvature of the object side surface of the first lens, it is ensured that the lens barrel does not intercept the imaging light, thus ensuring that the final imaging picture of the optical system does not have darkened corners, while limiting R1 to prevent the object side surface of the first lens from protruding out of the lens barrel, preventing the first lens from being damaged and other adverse problems, thus ensuring the stability of the assembly of the front lens, which is conducive to improving the overall yield during assembly.

[0056] In the present embodiment, the radius of curvature R3 of the object side surface of the second lens, the refractive index N2 of the second lens, and the outer diameter D2s of the object side surface of the second spacer satisfy: 0.39≤|R3×N2| / D2s≤1.17. Through the expression, the effective diameter surface of the second lens is optimized, ensuring that the optical ghost image of the optical system meets the minimum energy threshold requirement, while limiting D2s to ensure the width of the flange surface of the second lens, ensuring the range of the second lens, which is conducive to ensuring the stability of the assembly of the second lens.

[0057] In the present embodiment, the radius of curvature R4 of the image side surface of the second lens and the inner diameter d2s of the object side surface of the second spacer satisfy: -4.78≤R4 / d2s≤-0.59. Through the expression, it is ensured that the stray light path passing through the image side surface of the second lens can be intercepted by the second spacer, thus ensuring the imaging quality of the optical system, while ensuring the accurate transmission of the light rays and the smoothness of the light ray transmission.

[0058] In the present embodiment, the axial interval EP34 between the third spacer and the fourth spacer and the central thickness CT4 of the fourth lens on the optical axis satisfy: 0.54≤CT4 / EP34≤1.76. Through the expression, the uniformity of the overall thickness of the fourth lens is ensured, and no molding problems occur during the molding of the fourth lens, thus ensuring the effective diameter surface and appearance of the fourth lens.

[0059] In the embodiment, the air interval T34 of the third lens and the fourth lens on the optical axis and the maximum axial thickness CP3 of the third spacer satisfy: 0.11≤T34 / CP3≤4.55. By limiting the air interval of the third lens and the fourth lens on the optical axis through the expression, the distance between the third lens and the fourth lens is shortened, and the resolving power of the optical system can be improved; meanwhile, the minimum value of the maximum axial thickness of the third spacer is ensured, the improvement space of stray light is ensured, and the structural feasibility of the optical system is met.

[0060] In the embodiment, the curvature radius R5 of the object side surface of the third lens and the inner diameter d3s of the object side surface of the third spacer satisfy: -5.32≤R5 / d3s≤-0.36. Through the expression, it can be ensured that the stray light passing through the object side surface of the third lens is intercepted by the third spacer, so as to improve the stray light and ensure the final imaging quality of the optical system; the inner diameter of the object side surface of the third spacer is limited, and meanwhile, the normal light of the optical system can pass smoothly, the light quantity is ensured, and the imaging brightness is ensured.

[0061] In the embodiment, the outer diameter D3s of the object side surface of the third spacer and the curvature radius R6 of the image side surface of the third lens satisfy: 1.69≤|D3s / R6|≤4.33. Through the expression, the stray light improvement effect of the optical system is ensured, the stray light can be reflected multiple times through the edge structure area of the third lens, so as to weaken the stray light energy, and meanwhile, the curvature radius of the image side surface of the third lens is limited, and it can also be ensured that the stray light cannot be transmitted to the final imaging surface.

[0062] In the embodiment, the object side surface of the fifth lens is a convex surface, the outer diameter D4m of the image side surface of the fourth spacer and the curvature radius R9 of the object side surface of the fifth lens satisfy: 1.28≤D4m / R9≤4.34. Through the expression, the radial bearing width of the object side surface of the fifth lens is ensured, and the assembly stability of the optical system is ensured; meanwhile, the light can be accurately transmitted according to the design path.

[0063] Optionally, the optical system in the embodiment of the application can be simulated by software and / or tools such as ZEMAX, CODEV, etc. In the process of simulation by software and / or tools such as the above, the surface shape of each lens can be simulated according to the surface shape provided by the software and / or the tool used.

[0064] In addition, in another optional embodiment of the present application, an optical system is also provided, comprising a lens barrel, a lens set arranged in the lens barrel, and at least one spacer, the lens set is composed of five lenses, the five lenses are, in order from the object side to the image side, a first lens with negative refractive power, a second lens with positive refractive power, a third lens with refractive power, a fourth lens with refractive power, and a fifth lens with refractive power, the object side surface of the first lens is concave, the image side surface of the second lens is convex, and the object side surface of the third lens is concave; the at least one spacer comprises a first spacer arranged between the first lens and the second lens and partially in contact with the image side surface of the first lens, a second spacer arranged between the second lens and the third lens and partially in contact with the image side surface of the second lens, and a third spacer arranged between the third lens and the fourth lens and partially in contact with the image side surface of the third lens; the axial interval EP01 between the object side end surface of the lens barrel and the first spacer and the central thickness CT1 of the first lens on the optical axis of the optical system satisfy: 1.92≤EP01 / CT1≤3.08; and the inner diameter d0s of the object side end surface of the lens barrel and the curvature radius R1 of the object side surface of the first lens satisfy: -3.21≤d0s / R1≤-1.15.

[0065] The optical system of the present application is composed of a lens barrel, five lenses arranged in the lens barrel, and a plurality of spacers. By reasonably arranging the refractive power and surface shape of the five lenses, the positions of the first spacer, the second spacer, and the third spacer, and setting the optical system to satisfy -1.92≤EP01 / CT1≤3.08, the edge thickness of the first lens is controlled while the central thickness of the first lens is limited to meet the performance requirements. However, in the case of controlling the edge thickness and the central thickness of the first lens, the optical system is easily affected by the central thickness and the surface shape of the first lens, leading to assembly deviation, poor assembly stability, and deviation of the defocus curve after assembly of the optical system, thereby affecting the optical performance of the optical system. Therefore, by limiting -3.21≤d0s / R1≤-1.15, the ratio between the inner diameter of the object side end surface of the lens barrel and the curvature radius of the object side surface of the first lens is limited, which can ensure that the lens barrel does not intercept imaging light, thereby ensuring that the final imaging image of the optical system does not become dark in the corners, limiting R1 to prevent the object side surface of the first lens from protruding out of the lens barrel, preventing the first lens from being damaged, and ensuring the assembly stability of the front lens, which is conducive to improving the overall yield during assembly.

[0066] Of course, the present embodiment can also include other parameter formulas in the above embodiments, which will not be described here.

[0067] In another optional embodiment of the present application, an optical system is provided, comprising a lens barrel, a lens set arranged in the lens barrel, and at least one spacer, the lens set comprising five lenses arranged in order from an object side to an image side as a first lens having a negative focal power, a second lens having a positive focal power, a third lens having a focal power, a fourth lens having a focal power, and a fifth lens having a focal power, the object side surface of the first lens being concave, the image side surface of the second lens being convex, and the object side surface of the third lens being concave; the at least one spacer comprising a first spacer arranged between the first lens and the second lens and partially in contact with the image side surface of the first lens, and a second spacer arranged between the second lens and the third lens and partially in contact with the image side surface of the second lens; the effective focal length f1 of the first lens and the central thickness CT1 of the first lens on the optical axis of the optical system satisfying -25.35≤f1 / CT1≤-1.49; and the outer diameter D2s of the object side surface of the second spacer, the inner diameter d2s of the object side surface of the second spacer, and the radius of curvature R2 of the image side surface of the first lens satisfying -0.79≤(D2s-d2s) / R2≤4.67.

[0068] The optical system of the present application comprises a lens barrel, five lenses arranged in the lens barrel, and a plurality of spacers. By reasonably arranging the focal powers and surface shapes of the five lenses, the positions of the first spacer and the second spacer, and setting the optical system to satisfy -25.35≤f1 / CT1≤-1.49, the relationship between the effective focal length of the first lens and the central thickness of the first lens can be constrained within a reasonable range, which is conducive to controlling the reasonableness of the central thickness of the first lens, ensuring the stability of the deflection of light rays by the first lens, and meeting the requirements of the angle of incidence of light rays. However, in this case, it is difficult to ensure the assembly stability of the front lens in the lens barrel. Therefore, by constraining -0.79≤(D2s-d2s) / R2≤4.67, the present application is conducive to ensuring the contact width of the second spacer and the first lens, ensuring that the contact area meets the requirements of assembly stability, and avoiding the case that the image side surface of the second lens is too curved, thereby ensuring the smoothness of the path of light rays.

[0069] Of course, the present embodiment can also include other parameter formulas in the above embodiments, which will not be described here.

[0070] Optionally, the optical system described above can further comprise a protective glass for protecting the photosensitive elements located on the imaging surface.

[0071] The optical system in the present application can employ multiple lenses, for example, five lenses as described above. In the present application, at least one of the mirror surfaces of each lens is an aspheric mirror surface. The aspheric lens is characterized in that the curvature is continuously changed from the center of the lens to the periphery of the lens. Unlike the spherical lens which has a constant curvature from the center of the lens to the periphery of the lens, the aspheric lens has a better curvature radius characteristic, which has the advantages of improving the distortion aberration and improving the astigmatism aberration. After the aspheric lens is employed, the aberration that occurs during imaging can be eliminated as much as possible, thereby improving the imaging quality.

[0072] However, those skilled in the art should understand that the number of lenses constituting the optical system can be changed without departing from the technical solutions claimed by the present application, to obtain the various results and advantages described in the present specification. For example, although five lenses are described as an example in the embodiments, the optical system is not limited to including five lenses. If necessary, the optical system can also include other numbers of lenses.

[0073] Figure 1 The size annotation diagram of one optical system of the present application is shown, Figure 1 The parameters D3s, D2s, d0s, d3s, d2s, D4m, CP1, CP3, EP01, EP12, EP23, EP34, etc. are marked in the figure, so that the meaning of the parameters can be clearly and intuitively understood. In order to facilitate the description of the optical system and the surface shape of the specific lens, these parameters will not be embodied in the figure when the specific embodiments are described later.

[0074] The specific surface shape and parameters of the optical system applicable to the above-described embodiments will be further described below with reference to the accompanying drawings.

[0075] It should be noted that there are three examples of embodiment 1-1, embodiment 1-2, embodiment 1-3 in the following embodiment one, there are three examples of embodiment 2-1, embodiment 2-2, embodiment 2-3 in the following embodiment two, and there are three examples of embodiment 3-1, embodiment 3-2, embodiment 3-3 in the following embodiment three. The curvature radius, center thickness, etc. of the first lens to the fifth lens of the optical system in the three examples in the same embodiment are the same, but the thickness, inner diameter and outer diameter of the lens barrel, the first spacer to the fourth spacer are different. Or, the main structure for imaging is the same, and the auxiliary structure for imaging is different.

[0076] It should be noted that any one of the following embodiment one to embodiment three is applicable to all embodiments of the present application.

[0077] Embodiment one

[0078] As Figures 2 to 8As shown in FIG. 1, an optical system according to Embodiment 1 is described. Figure 2 As shown in FIG. 2, a structural schematic diagram of the optical system according to Embodiment 1-1 is shown. Figure 3 As shown in FIG. 3, a structural schematic diagram of the optical system according to Embodiment 1-2 is shown. Figure 4 As shown in FIG. 4, a structural schematic diagram of the optical system according to Embodiment 1-3 is shown.

[0079] As shown in FIG. 1, the optical system includes a lens barrel P0 and, arranged in the lens barrel P0 along the optical axis from the object side to the image side in sequence, a first lens E1, a first spacer P1, a first auxiliary spacer P1b, a second lens E2, a second spacer P2, a third lens E3, a third spacer P3, a fourth lens E4, a fourth spacer P4, and a fifth lens E5. Figures 2 to 4 As shown in FIG. 2, a structural schematic diagram of the optical system according to Embodiment 1-1 is shown. In this example, the image side of the fourth spacer P4 is further provided with a fourth auxiliary spacer P4b. Specifically, the object side surface and the image side surface of the first spacer P1 are in contact with the image side surface S2 of the first lens and the object side surface of the first auxiliary spacer P1b, respectively, and the image side surface of the first auxiliary spacer P1b is in contact with the object side surface S3 of the second lens. The object side surface and the image side surface of the second spacer P2 are in contact with the image side surface S4 of the second lens and the object side surface S5 of the third lens, respectively. The object side surface and the image side surface of the third spacer P3 are in contact with the image side surface S6 of the third lens and the object side surface S7 of the fourth lens, respectively. The object side surface and the image side surface of the fourth spacer P4 are in contact with the image side surface S8 of the fourth lens and the object side surface of the fourth auxiliary spacer P4b, respectively, and the image side surface of the fourth auxiliary spacer P4b is in contact with the object side surface S9 of the fifth lens.

[0080] Figure 2 As shown in FIG. 3, a structural schematic diagram of the optical system according to Embodiment 1-2 is shown. In this example, no fourth auxiliary spacer P4b is provided, and thus the object side surface and the image side surface of the fourth spacer P4 are in contact with the image side surface S8 of the fourth lens and the object side surface S9 of the fifth lens, respectively. The abutting contact modes of the remaining spacers are the same as those of Embodiment 1-1, and reference can be made to the related descriptions in Embodiment 1-1, which will not be repeated here.

[0081] As shown in FIG. 4, a structural schematic diagram of the optical system according to Embodiment 1-3 is shown. In this example, the abutting contact modes of the spacers are the same as those of Embodiment 1-1, and reference can be made to the related descriptions in Embodiment 1-1, which will not be repeated here. Figure 3 As shown in FIG. 4, a structural schematic diagram of the optical system according to Embodiment 1-3 is shown. In this example, the abutting contact modes of the spacers are the same as those of Embodiment 1-1, and reference can be made to the related descriptions in Embodiment 1-1, which will not be repeated here.

[0082] Figure 4 As shown in FIG. 4, a structural schematic diagram of the optical system according to Embodiment 1-3 is shown. In this example, the abutting contact modes of the spacers are the same as those of Embodiment 1-1, and reference can be made to the related descriptions in Embodiment 1-1, which will not be repeated here.

[0083] In summary, the structural parameters of the optical system according to Embodiment 1 in Embodiments 1-1, 1-2, and 1-3 are shown in Table 2 (unit: mm). ​​

[0084] Table 2

[0085] Parameter / Example 1-1 1-2 1-3 d2s (mm) 0.652 0.650 0.658 D2s (mm) 2.316 2.713 2.675 d3s (mm) 0.936 0.961 0.940 D3s (mm) 2.416 2.813 2.775 D4m (mm) 2.380 2.913 2.875 d0s (mm) 2.288 2.019 2.159 CP1 (mm) 0.411 0.372 0.392 CP3 (mm) 0.022 0.022 0.022 EP01 (mm) 0.891 0.806 0.836 EP12 (mm) 0.356 0.383 0.345 EP23 (mm) 0.394 0.383 0.388 EP34 (mm) 0.305 0.418 0.294

[0086] In embodiment one, the object side S1 of the first lens is concave, the image side S2 of the first lens is convex. The object side S3 of the second lens is convex, the image side S4 of the second lens is convex. The object side S5 of the third lens is concave, the image side S6 of the third lens is concave. The object side S7 of the fourth lens is concave, the image side S8 of the fourth lens is convex. The object side S9 of the fifth lens is convex, the image side S10 of the fifth lens is concave.

[0087] In embodiment one, the effective focal length f1 of the first lens is -3.262mm, the effective focal length f2 of the second lens is 0.970mm, the effective focal length f3 of the third lens is -1.421mm, the effective focal length f4 of the fourth lens is 1.174mm, the effective focal length f5 of the fifth lens is -4.216mm.

[0088] Table 3 shows the basic structure parameter table of the optical system of embodiment one, wherein the units of the radius of curvature, thickness / distance are millimeters mm. In the following table, STO represents the physical stop position.

[0089] Table 3

[0090]

[0091] In embodiment one, the object side and the image side of the first lens E1 to the fifth lens E5 are aspherical surfaces, the surface type of each aspherical lens can be defined by but not limited to the following aspherical formula:

[0092]

[0093] Wherein, x is the distance sag of the aspherical surface at the height h along the optical axis direction from the vertex of the aspherical surface; c is the paraxial curvature of the aspherical surface, c = 1 / R, i.e. the paraxial curvature c is the reciprocal of the radius of curvature R in the above table 3; k is the conic coefficient; Ai is the correction coefficient of the i-th order of the aspherical surface. The following table 4 shows the high order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28, A30 which can be used for each aspherical mirror S1-S10 in embodiment one.

[0094] Table 4

[0095]

[0096]

[0097] Figure 5An on-axis chromatic aberration curve of the optical system of embodiment one is shown, which represents the convergence point deviation of light rays of different wavelengths after passing through the imaging lens. Figure 6 An astigmatism curve of the optical system of embodiment one is shown, which represents the meridional image curvature and sagittal image curvature. Figure 7 A distortion curve of the optical system of embodiment one is shown, which represents the distortion size values corresponding to different field angles. Figure 8 A lateral chromatic aberration curve of the optical system of embodiment one is shown, which represents the deviation of light rays on the imaging plane after passing through the optical system.

[0098] According to Figures 5 to 8 It can be seen that the optical system given by embodiment one can achieve good imaging quality.

[0099] Embodiment two

[0100] As shown in Figures 9 to 15 , an optical system of embodiment two is described. Figure 9 A structural schematic diagram of the optical system of embodiment 2-1 is shown, Figure 10 A structural schematic diagram of the optical system of embodiment 2-2 is shown, Figure 11 A structural schematic diagram of the optical system of embodiment 2-3 is shown.

[0101] As shown in Figures 9 to 11 , the optical system includes a lens barrel P0 and, arranged in the lens barrel P0 along the optical axis from the object side to the image side in sequence, a first lens E1, a first spacer P1, a first auxiliary spacer P1b, a second lens E2, a second spacer P2, a third lens E3, a third spacer P3, a fourth lens E4, a fourth spacer P4, and a fifth lens E5.

[0102] As shown in Figure 9 , a structural schematic diagram of the optical system of embodiment 2-1 is shown. In this example, the image side of the third spacer P3 is further provided with a third auxiliary spacer P3b. Specifically, the object side surface and the image side surface of the first spacer P1 are in contact with the image side surface S2 of the first lens and the object side surface of the first auxiliary spacer P1b, respectively, and the image side surface of the first auxiliary spacer P1b is in contact with the object side surface S3 of the second lens. The object side surface and the image side surface of the second spacer P2 are in contact with the image side surface S4 of the second lens and the object side surface S5 of the third lens, respectively. The object side surface and the image side surface of the third spacer P3 are in contact with the image side surface S6 of the third lens and the object side surface of the third auxiliary spacer P3b, respectively, and the image side surface of the third auxiliary spacer P3b is in contact with the object side surface S7 of the fourth lens. The object side surface and the image side surface of the fourth spacer P4 are in contact with the image side surface S8 of the fourth lens and the object side surface S9 of the fifth lens, respectively.

[0103] As shown in Figure 10The diagram shown is a structural schematic of the optical system in Embodiment 2-2. In this example, the bearing and contact method of each spacer is the same as in Embodiment 2-1, and can be referred to the relevant description in Embodiment 2-1, which will not be repeated here.

[0104] like Figure 11 The diagram shown is a schematic representation of the optical system in Embodiment 2-3. In this example, the third auxiliary spacer P3b is not provided. Therefore, the object-side and image-side of the third spacer P3 partially contact the image-side S6 of the third lens and the object-side S7 of the fourth lens, respectively. The contact method of the remaining spacers is the same as in Embodiment 2-1, and can be referred to the relevant description in Embodiment 2-1, which will not be repeated here.

[0105] In summary, the structural parameters of the optical system in Embodiment 2 under Embodiments 2-1, 2-2, and 2-3 are shown in Table 5. (Unit: mm)

[0106] Table 5

[0107] Parameter / Example 2-1 2-2 2-3 d2s (mm) 0.919 0.882 0.936 D2s (mm) 2.819 2.971 2.972 d3s (mm) 1.163 1.177 1.337 D3s (mm) 2.781 3.071 3.072 D4m (mm) 3.119 3.271 3.172 d0s (mm) 2.917 2.665 2.730 CP1 (mm) 0.342 0.421 0.340 CP3 (mm) 0.462 0.022 0.022 EP01 (mm) 0.686 0.547 0.670 EP12 (mm) 0.331 0.291 0.335 EP23 (mm) 0.289 0.362 0.479 EP34 (mm) 0.319 0.734 0.544

[0108] In Embodiment 2, the object-side surface S1 of the first lens is concave, and the image-side surface S2 of the first lens is convex. The object-side surface S3 of the second lens is concave, and the image-side surface S4 of the second lens is convex. The object-side surface S5 of the third lens is concave, and the image-side surface S6 of the third lens is convex. The object-side surface S7 of the fourth lens is convex, and the image-side surface S8 of the fourth lens is concave. The object-side surface S9 of the fifth lens is convex, and the image-side surface S10 of the fifth lens is concave.

[0109] In Example 2, the effective focal length f1 of the first lens is -5.646mm, the effective focal length f2 of the second lens is 1.297mm, the effective focal length f3 of the third lens is -1.867mm, the effective focal length f4 of the fourth lens is 1.609mm, and the effective focal length f5 of the fifth lens is 12.888mm.

[0110] Table 6 shows the basic structural parameters of the optical system in Embodiment 2, where the units for radius of curvature and thickness / distance are millimeters (mm). In the table below, STO represents the physical aperture position.

[0111] Table 6

[0112]

[0113]

[0114] The following Table 7 shows the high-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28, A30 of each aspherical mirror S1-S10 used in Example Two.

[0115] Table 7

[0116] Surface number A4 A6 A8 A10 A12 A14 A16 S1 3.5369E-01 -6.9083E-02 4.6465E-03 -2.9186E-03 9.9023E-04 -8.3372E-05 1.0487E-04 S2 1.9526E-01 -5.9618E-02 5.0423E-03 6.8243E-04 4.5931E-04 -2.3784E-04 -4.7172E-06 S3 -1.7854E-02 -8.1443E-04 -1.1588E-04 -9.4918E-06 8.2103E-07 4.6001E-06 3.2719E-07 S4 3.9077E-02 1.1837E-03 -7.7089E-04 -2.9707E-04 5.4891E-06 1.0557E-05 2.9636E-06 S5 1.6568E-01 -9.0989E-03 1.1639E-04 -4.9259E-04 3.1427E-04 -7.2662E-05 9.2983E-07 S6 -4.9536E-02 1.2546E-02 2.3204E-03 -3.5369E-04 -5.6050E-05 -8.8827E-05 1.7741E-05 S7 -2.5171E-01 2.4876E-02 -2.6205E-03 1.6482E-03 -5.7555E-04 2.3151E-05 -1.3493E-05 S8 -1.7274E-01 4.3770E-03 7.6075E-03 -3.1452E-04 -3.4592E-04 -1.5970E-04 2.2665E-05 S9 -5.1461E-01 6.3149E-02 8.1031E-03 -5.5643E-03 2.4127E-04 4.0505E-04 -5.0363E-05 S10 -4.8477E-01 7.4432E-02 -7.7991E-03 -3.8185E-03 1.9349E-03 -4.4833E-04 1.0702E-04 Surface number A18 A20 A22 A24 A26 A28 A30 S1 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S2 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S3 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S4 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S5 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S6 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S7 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S8 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S9 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S10 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00

[0117] Figure 12 An on-axis chromatic aberration curve of the optical system of Example Two is shown, which represents the deviation of convergent focal points of light rays of different wavelengths after passing through the imaging lens. Figure 13 An astigmatism curve of the optical system of Example Two is shown, which represents the meridional image surface curvature and sagittal image surface curvature. Figure 14 A distortion curve of the optical system of Example Two is shown, which represents the distortion size values corresponding to different field angles. Figure 15 A magnification chromatic aberration curve of the optical system of Example Two is shown, which represents the deviation of light rays on the imaging surface after passing through the optical system at different image heights.

[0118] According to Figures 12 to 15 It can be seen that the optical system given in Example Two can achieve good imaging quality.

[0119] Example Three

[0120] As shown in Figures 16 to 22 , the optical system of Example Three is described. Figure 16 A structural schematic diagram of the optical system of Example 3-1 is shown, Figure 17 A structural schematic diagram of the optical system of Example 3-2 is shown, Figure 18 A structural schematic diagram of the optical system of Example 3-3 is shown.

[0121] As shown in Figures 16 to 18 , the optical system includes a lens barrel P0 and a first lens E1, a first spacer P1, a second lens E2, a second spacer P2, a third lens E3, a third spacer P3, a fourth lens E4, a fourth spacer P4, and a fifth lens E5 arranged in the lens barrel P0 in order from the object side to the image side along the optical axis. The optical system of the present embodiment is a flip structure, that is, each element in the lens barrel P0 is sequentially assembled into the lens barrel P0 from the object side to the image side in order from the object side of the lens barrel P0.

[0122] As shown in Figure 16Fig. 3-1 shows a structural schematic diagram of the optical system of Example 3-1. In this example, the object side and image side of the first spacer P1 are partially in contact with the image side S2 of the first lens and the object side S3 of the second lens, respectively. The object side and image side of the second spacer P2 are partially in contact with the image side S4 of the second lens and the object side S5 of the third lens, respectively. The object side and image side of the third spacer P3 are partially in contact with the image side S6 of the third lens and the object side S7 of the fourth lens, respectively. The object side and image side of the fourth spacer P4 are partially in contact with the image side S8 of the fourth lens and the object side S9 of the fifth lens, respectively.

[0123] As shown in Fig. 3-2, a structural schematic diagram of the optical system of Example 3-2 is shown. In this example, the abutting contact mode of each spacer is the same as that of Example 3-1, and the relevant description in Example 3-1 can be referred to, which will not be repeated here. Figure 17 As shown in Fig. 3-3, a structural schematic diagram of the optical system of Example 3-3 is shown. In this example, the abutting contact mode of each spacer is the same as that of Example 3-1, and the relevant description in Example 3-1 can be referred to, which will not be repeated here.

[0124] Figure 18 As shown in Fig. 3-3, a structural schematic diagram of the optical system of Example 3-3 is shown. In this example, the abutting contact mode of each spacer is the same as that of Example 3-1, and the relevant description in Example 3-1 can be referred to, which will not be repeated here.

[0125] In summary, the structural parameters of the optical system of Example Three under Example 3-1, Example 3-2, and Example 3-3 are shown in Table 8 (unit: mm).

[0126] Table 8

[0127] Parameter / Example 3-1 3-2 3-3 d2s (mm) 0.861 0.887 0.863 D2s (mm) 2.307 3.379 2.102 d3s (mm) 0.650 0.680 0.710 D3s (mm) 2.107 2.979 1.161 D4m (mm) 1.907 2.579 1.146 d0s (mm) 4.744 4.419 4.783 CP1 (mm) 0.022 0.022 0.022 CP3 (mm) 0.022 0.022 0.186 EP01 (mm) 1.021 1.107 1.373 EP12 (mm) 0.636 0.633 0.631 EP23 (mm) 0.419 0.418 0.364 EP34 (mm) 0.360 0.357 0.261

[0128] In Example Three, the object side S1 of the first lens is a concave surface, and the image side S2 of the first lens is a concave surface. The object side S3 of the second lens is a convex surface, and the image side S4 of the second lens is a convex surface. The object side S5 of the third lens is a concave surface, and the image side S6 of the third lens is a convex surface. The object side S7 of the fourth lens is a concave surface, and the image side S8 of the fourth lens is a concave surface. The object side S9 of the fifth lens is a convex surface, and the image side S10 of the fifth lens is a convex surface.

[0129] In Example Three, the effective focal length f1 of the first lens is -0.682 mm, the effective focal length f2 of the second lens is 1.160 mm, the effective focal length f3 of the third lens is 35.279 mm, the effective focal length f4 of the fourth lens is -2.913 mm, and the effective focal length f5 of the fifth lens is 0.745 mm.

[0130] Table 9 shows the basic structural parameter table of the optical system of Example Three, wherein the units of the curvature radius and the thickness / distance are millimeters (mm). In the following table, STO represents the physical stop position.

[0131] ​Table 9

[0132]

[0133] The following Table 10 shows the high order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28, A30 of each aspherical mirror S1-S10 used in Example Three.

[0134] Table 10

[0135]

[0136]

[0137] Figure 19 The on-axis chromatic aberration curve of the optical system of Example Three is shown, which represents the deviation of convergent focal points of light rays of different wavelengths after passing through the imaging lens. Figure 20 The astigmatism curve of the optical system of Example Three is shown, which represents the meridional image surface curvature and sagittal image surface curvature. Figure 21 The distortion curve of the optical system of Example Three is shown, which represents the distortion size values corresponding to different field angles. Figure 22 The magnification chromatic aberration curve of the optical system of Example Three is shown, which represents the deviation of light rays on the imaging surface after passing through the optical system at different image heights.

[0138] According to Figures 19 to 22 It can be seen that the optical system given in Example Three can achieve good imaging quality.

[0139] In summary, Examples One to Three respectively satisfy the relationships shown in Table 11.

[0140] Table 11

[0141] Condition / Example 1-1 1-2 1-3 2-1 2-2 2-3 3-1 3-2 3-3 EP01 / CT1 2.12 1.92 1.99 3.08 2.46 3.01 2.24 2.42 3.01 (CP1+T12) / CT1 2.09 2.00 2.04 4.45 4.80 4.44 0.98 0.98 0.98 f2 / EP12 2.72 2.53 2.81 3.92 4.46 3.87 1.82 1.83 1.84 d0s / R1 -2.33 -2.05 -2.20 -1.25 -1.15 -1.17 -3.19 -2.97 -3.21 |R3xN2| / D2s 0.45 0.39 0.39 1.17 1.10 1.10 0.60 0.41 0.66 R4 / d2s -2.73 -2.74 -2.71 -0.60 -0.63 -0.59 -4.78 -4.63 -4.76 (EP23+T23) / CT3 2.86 2.80 2.83 1.04 1.27 1.64 1.91 1.90 1.71 CT4 / EP34 1.69 1.24 1.76 1.24 0.54 0.72 0.69 0.70 0.96 T34 / CP3 4.00 4.00 4.00 0.11 2.27 2.27 4.55 4.55 0.54 R5 / d3s -5.32 -5.18 -5.30 -0.41 -0.41 -0.36 -0.94 -0.90 -0.86 |D3s / R6| 2.13 2.48 2.45 2.41 2.66 2.66 3.06 4.33 1.69 D4m / R9 3.50 4.28 4.23 4.14 4.34 4.21 2.13 2.88 1.28 f1 / CT1 -7.75 -7.75 -7.75 -25.38 -25.38 -25.38 -1.49 -1.49 -1.49 (D2s-d2s) / R2 -0.64 -0.79 -0.78 -0.18 -0.20 -0.19 2.71 4.67 2.32

[0142] Table 12 shows the effective focal length and the like of each lens of the optical systems of Examples One to Three.

[0143] Table 12

[0144] Parameter / Example One Two Three f1 (mm) -3.262 -5.646 -0.682 f2 (mm) 0.970 1.297 1.160 f3 (mm) -1.421 -1.867 35.279 f4 (mm) 1.174 1.609 -2.913 f5 (mm) -4.216 12.888 0.745

[0145] The present application also provides an imaging device, the electronic photosensitive element of which can be a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). The imaging device can be a stand-alone imaging apparatus such as a digital camera, or an imaging module integrated on a mobile electronic device such as a mobile phone. The imaging device is equipped with the optical system described above.

[0146] Obviously, the above-described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the protection scope of the present application.

[0147] It is to be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, devices, components and / or combinations thereof, but do not preclude the presence or addition of one or more other features, steps, operations, devices, components and / or combinations thereof.

[0148] It should be noted that the terms "first", "second", and the like, used in the specification and the claims of the application, as well as above-described appended drawings, are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the application described herein can be implemented in an order other than that illustrated or described herein.

[0149] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. An optical system, characterized in that, Includes a lens barrel, a lens assembly disposed within the lens barrel, and at least one spacer. The lens group consists of five lenses, which are arranged in the following order 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 optical power, a fourth lens with optical power, and a fifth lens with optical power. The object side of the first lens is concave, the image side of the second lens is convex, and the object side of the third lens is concave. The at least one spacer includes a first spacer placed between the first lens and the second lens and in contact with the image-side portion of the first lens, a second spacer placed between the second lens and the third lens and in contact with the image-side portion of the second lens, and a third spacer placed between the third lens and the fourth lens and in contact with the image-side portion of the third lens. The axial distance EP01 between the object-side end face of the lens barrel and the first spacer satisfies the following condition with respect to the center thickness CT1 of the first lens on the optical axis of the optical system: 1.92≤EP01 / CT1≤3.08; The air gap T23 between the second lens and the third lens on the optical axis, the axial gap EP23 between the second spacer and the third spacer, and the center thickness CT3 of the third lens on the optical axis satisfy the following: 1.04≤(EP23+T23) / CT3≤2.

86.

2. The optical system according to claim 1, characterized in that, The maximum axial thickness CP1 of the first spacer, the air gap T12 between the first lens and the second lens on the optical axis and the center thickness CT1 of the first lens on the optical axis satisfy the following condition: 0.98≤(CP1+T12) / CT1≤4.

80.

3. The optical system according to claim 1, characterized in that, The effective focal length f2 of the second lens satisfies the following condition with respect to the axial distance EP12 between the first spacer and the second spacer: 1.82≤f2 / EP12≤4.

46.

4. The optical system according to claim 1, characterized in that, The inner diameter d0s of the object-side end face of the lens barrel and the radius of curvature R1 of the object-side surface of the first lens satisfy the following condition: -3.21≤d0s / R1≤-1.

15.

5. The optical system according to claim 1, characterized in that, The radius of curvature R3 of the object side surface of the second lens, the refractive index N2 of the second lens, and the outer diameter D2s of the object side surface of the second spacer satisfy the following condition: 0.39≤|R3×N2| / D2s≤1.

17.

6. The optical system according to claim 1, characterized in that, The radius of curvature R4 of the image side of the second lens and the inner diameter d2s of the object side of the second spacer satisfy the following condition: -4.78≤R4 / d2s≤-0.

59.

7. The optical system according to claim 1, characterized in that, The at least one spacer further includes a fourth spacer disposed between the fourth lens and the fifth lens, wherein the axial spacing EP34 between the third spacer and the fourth spacer satisfies the following condition with respect to the center thickness CT4 of the fourth lens on the optical axis: 0.54≤CT4 / EP34≤1.

76.

8. The optical system according to claim 1, characterized in that, The air gap T34 between the third lens and the fourth lens on the optical axis and the maximum axial thickness CP3 of the third spacer satisfy the following condition: 0.11≤T34 / CP3≤4.

55.

9. The optical system according to claim 1, characterized in that, The radius of curvature R5 of the object side surface of the third lens and the inner diameter d3s of the object side surface of the third spacer satisfy the following condition: -5.32≤R5 / d3s≤-0.

36.

10. The optical system according to claim 1, characterized in that, The outer diameter D3 of the object side of the third spacer and the radius of curvature R6 of the image side of the third lens satisfy the following condition: 1.69≤|D3s / R6|≤4.

33.

11. The optical system according to claim 1, characterized in that, The at least one spacer further includes a fourth spacer disposed between the fourth lens and the fifth lens, wherein the object-side surface of the fifth lens is convex, and the outer diameter D4m of the image-side surface of the fourth spacer and the radius of curvature R9 of the object-side surface of the fifth lens satisfy the following condition: 1.28≤D4m / R9≤4.34.

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