Optical system

Abstract

The invention 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. The problem that in the prior art, a five-piece optical system meets the optical performance requirement by restraining the size of a front-end lens, so that the assembling stability is poor, and then a defocus curve deviates is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of optical imaging equipment, and in particular to an optical system. Background Art

[0002] In the design and application of modern optical systems, five-element optical systems are widely used in mobile phone lenses, miniature cameras and other equipment due to their compact structure and excellent imaging performance.

[0003] However, the five-piece optical system in the prior art faces many challenges in the process of design and manufacturing. In order to meet the requirements of optical performance, it is usually necessary to constrain the size of the front lens. Although this design can optimize the optical performance to a certain extent, it is also easy for factors such as the size and surface shape of the front lens to affect the assembly stability of the front and rear elements in the lens barrel. Poor assembly stability can easily lead to the deviation of the optical system, which in turn can easily lead to the deviation of the defocus curve, resulting in poor optical performance of the optical system.

[0004] That is to say, the five-piece optical system in the prior art has the problem of poor assembly stability due to the constraint of the size of the front lens to meet the optical performance requirements, which in turn causes the defocus curve to shift. Summary of the invention

[0005] The main purpose of the present invention is to provide an optical system to solve the problem that the five-piece optical system in the prior art meets the optical performance requirements by constraining the size of the front lens, resulting in poor assembly stability and further causing the defocus curve to shift.

[0006] To achieve the above-mentioned object, according to one aspect of the present invention, an optical system is provided, comprising a lens barrel, a lens group and at least one spacer arranged in the lens barrel, wherein the lens group is composed of five lenses, and the five lenses are, 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 surface of the first lens is a concave surface, the image side surface of the second lens is a convex surface, and the object side surface of the third lens is a concave surface; the at least one spacer comprises a first spacer placed between the first lens and the second lens and in contact with a portion of the image side surface of the first lens, a spacer placed between the second lens and the third lens and in contact with a portion of the image side surface of the first lens, A second spacer is disposed between the three lenses and in contact with the image side surface of the second lens, and a third spacer is disposed between the third lens and the fourth lens and in contact with the image side surface of the third lens; an axial spacing EP01 between the object side end surface of the lens barrel and the first spacer and a center thickness CT1 of the first lens on the optical axis of the optical system satisfy the following: 1.92≤EP01 / CT1≤3.08; an air spacing T23 on the optical axis between the second lens and the third lens, an axial spacing EP23 between the second spacer and the third spacer and a center thickness CT3 of the third lens on the optical axis satisfy the following: 1.04≤(EP23+T23) / CT3≤2.86.

[0007] According to another aspect of the present invention, an optical system is provided, comprising a lens barrel, a lens group and at least one spacer disposed in the lens barrel, wherein the lens group is composed of five lenses, and the five lenses are, from the object side to the image side, a first lens having negative optical power, a second lens having positive optical power, a third lens having optical power, a fourth lens having optical power and a fifth lens having optical power, wherein the object side surface of the first lens is a concave surface, the image side surface of the second lens is a convex surface, and the object side surface of the third lens is a concave surface; and the at least one spacer includes a lens disposed between the first lens and the second lens and partially contacting the image side surface of the first lens. a first spacer disposed between the second lens and the third lens and in contact with the image side surface portion of the second lens, and a third spacer disposed between the third lens and the fourth lens and in contact with the image side surface portion of the third lens; an axial spacing EP01 between the object side end surface of the lens barrel and the first spacer and a center thickness CT1 of the first lens on the optical axis of the optical system satisfy: 1.92≤EP01 / CT1≤3.08; an inner diameter d0s of the object side end surface of the lens barrel and a 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 present invention, an optical system is provided, comprising a lens barrel, a lens group and at least one spacer arranged in the lens barrel, wherein the lens group is composed of five lenses, and the five lenses are, 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, wherein the object side surface of the first lens is a concave surface, the image side surface of the second lens is a convex surface, and the object side surface of the third lens is a concave surface; and the at least one spacer includes a spacer disposed between the first lens and the second lens. A first spacer in contact with the image side surface of the first lens, and a second spacer placed between the second lens and the third lens and in contact with the image side surface of the second lens; the effective focal length f1 of the first lens and the center thickness CT1 of the first lens on the optical axis satisfy: -25.35≤f1 / CT1≤-1.49; 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 curvature radius R2 of the image side surface of the first lens satisfy: -0.79≤(D2s-d2s) / R2≤4.67.

[0009] Further, the maximum axial thickness CP1 of the first spacer, the air interval 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: 0.98≤(CP1+T12) / CT1≤4.80.

[0010] Further, 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.

[0011] Furthermore, 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.

[0012] Further, a curvature radius R3 of the object-side surface of the second lens, a refractive index N2 of the second lens, and an outer diameter D2s of the object-side surface of the second spacer satisfy: 0.39≤|R3×N2| / D2s≤1.17.

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

[0014] Furthermore, the at least one spacer also includes a fourth spacer disposed between the fourth lens and the fifth lens, and an axial interval EP34 between the third spacer and the fourth spacer and a center thickness CT4 of the fourth lens on the optical axis satisfy: 0.54≤CT4 / EP34≤1.76.

[0015] Further, an air interval T34 between the third lens and the fourth lens on the optical axis and a maximum axial thickness CP3 of the third spacer satisfy: 0.11≤T34 / CP3≤4.55.

[0016] Further, a curvature radius R5 of the object-side surface of the third lens and an inner diameter d3s of the object-side surface of the third spacer satisfy: -5.32≤R5 / d3s≤-0.36.

[0017] Further, an outer diameter D3 of the object-side surface of the third spacer and a curvature radius R6 of the image-side surface of the third lens satisfy: 1.69≤|D3s / R6|≤4.33.

[0018] Furthermore, the at least one spacer also includes a fourth spacer placed between the fourth lens and the fifth lens, the object side surface of the fifth lens is a convex surface, and 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.

[0019] By applying the technical solution of the present invention, the optical system of the present application consists of a lens barrel, five lenses arranged in the lens barrel, and a plurality of spacers. By reasonably arranging the optical 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 and the center thickness of the first lens is limited to meet the performance requirements. However, when the edge thickness and center thickness of the first lens are controlled, the optical system is easily affected by factors such as the center thickness and surface shape of the first lens, resulting in assembly offset, thereby resulting in poor assembly stability, and further causing the defocus curve of the optical system after assembly to offset, affecting the optical performance of the optical system. Therefore, the present application ensures the assembly stability of the second lens and the third lens at the front end and reduces the sensitivity of optical performance by constraining 1.04≤(EP23+T23) / CT3≤2.86 and optimizing factors such as the air gap between the second lens and the third lens, the edge thickness of the second lens, and the center thickness of the third lens in the optical system. This ensures that the risk of the final optical system being affected by the defocus curve offset is small, and reduces the risk of the defocus curve offset after assembly, thereby ensuring the optical performance of the final optical system. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0021] Figure 1 A dimensioned diagram showing an optical system of an alternative embodiment of the present invention;

[0022] Figure 2 A schematic structural diagram of an optical system according to Embodiment 1-1 of the present invention is shown;

[0023] Figure 3 A schematic structural diagram of an optical system according to Embodiment 1-2 of the present invention is shown;

[0024] Figure 4 A schematic diagram showing the structure of an optical system of Embodiments 1-3 of the present invention is shown;

[0025] Figures 5 to 8 The axial chromatic aberration curve, the astigmatism curve, the distortion curve and the magnification chromatic aberration curve of the optical system of the first embodiment of the present invention are respectively shown;

[0026] Fig. 9 A schematic structural diagram of an optical system according to Embodiment 2-1 of the present invention is shown;

[0027] Fig.10 A schematic structural diagram of an optical system according to Embodiment 2-2 of the present invention is shown;

[0028] Fig.11 A schematic structural diagram of an optical system according to Embodiment 2-3 of the present invention is shown;

[0029] Figures 12 to 15 The axial chromatic aberration curve, astigmatism curve, distortion curve and magnification chromatic aberration curve of the optical system of the second embodiment of the present invention are respectively shown;

[0030] Fig.16 A schematic structural diagram of an optical system according to Embodiment 3-1 of the present invention is shown;

[0031] Fig.17 A schematic diagram showing the structure of an optical system of Example 3-2 of the present invention is shown;

[0032] Fig.18 A schematic structural diagram of an optical system according to Embodiment 3-3 of the present invention is shown;

[0033] Figures 19 to 22 The axial chromatic aberration curve, astigmatism curve, distortion curve and magnification chromatic aberration curve of the optical system of the third embodiment of the present invention are respectively shown;

[0034] Fig.23 A schematic diagram of a defocus curve when an optical system of an optional example of the present invention satisfies EP01 / CT1=2.42 and (EP23+T23) / CT3=1.90 is shown;

[0035] Fig.24A schematic diagram of a defocus curve when an optical system of an optional example satisfies EP01 / CT1=2.42 and (EP23+T23) / CT3=0.98 is shown;

[0036] Fig.25 A schematic diagram of a defocus curve when an optical system of another optional example satisfies EP01 / CT1=2.42 and (EP23+T23) / CT3=2.94 is shown.

[0037] The above drawings include the following reference numerals:

[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, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0040] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs.

[0041] In the present invention, unless otherwise specified, the directional words used, such as "up, down, top, bottom", usually refer to the directions shown in the drawings, or to the components themselves in the vertical, perpendicular or gravity directions; similarly, for ease of understanding and description, "inside and outside" refer to the inside and outside relative to the outline of each component itself, but the above-mentioned directional words are not used to limit the present invention.

[0042] It should be noted that in this 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, without departing from the teaching of the present application, the first lens discussed below may also be referred to as the second lens or the third lens.

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

[0044] 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 based on the judgment method of the general knowledge in this field, and the positive and negative R value (R refers to the radius of curvature of the paraxial area, usually refers to the R value on the lens database (lens data) in the optical software) is used to judge the convexity and concavity. For the object side, when the R value is positive, it is judged as a convex surface, and when the R value is negative, it is judged as a concave surface; for the image side, when the R value is positive, it is judged as a concave surface, and when the R value is negative, it is judged as a convex surface. In the present 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 meets the optical performance requirements by constraining the size of the front lens, resulting in poor assembly stability and further causing the defocus curve to shift, the present invention provides an optical system.

[0046] like Figures 1 to 25 As shown, in an optional embodiment of the present application, the optical system includes a lens barrel, a lens group and at least one spacer arranged in the lens barrel, the lens group consists of five lenses, and the five lenses are, 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 surface of the first lens is a concave surface, the image side surface of the second lens is a convex surface, and the object side surface of the third lens is a concave surface; 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 surface of the first lens, a spacer placed between the second lens and the third lens A second spacer is placed between the third lens and in contact with the image side surface portion of the second lens, and a third spacer is placed between the third lens and the fourth lens and in contact with the image side surface portion of the third lens; the axial spacing EP01 between the object side end surface of the lens barrel and the first spacer and the center thickness CT1 of the first lens on the optical axis of the optical system satisfy: 1.92≤EP01 / CT1≤3.08; the air spacing T23 on the optical axis between the second lens and the third lens, the axial spacing EP23 between the second spacer and the third spacer and the center 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, five lenses arranged in the lens barrel, and a plurality of spacers. By reasonably arranging the optical 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 and the center thickness of the first lens is limited to meet performance requirements. However, when the edge thickness and center thickness of the first lens are controlled, the optical system is easily affected by factors such as the center thickness and surface shape of the first lens, resulting in assembly offset, thereby resulting in poor assembly stability, and further causing the defocus curve of the optical system to be offset after assembly, affecting the optical performance of the optical system. Therefore, the present application ensures the assembly stability of the second lens and the third lens at the front end and reduces the sensitivity of optical performance by constraining 1.04≤(EP23+T23) / CT3≤2.86 and optimizing factors such as the air gap between the second lens and the third lens, the edge thickness of the second lens, and the center thickness of the third lens in the optical system. This ensures that the risk of the final optical system being affected by the defocus curve offset is small, and reduces the risk of the defocus curve offset after assembly, thereby ensuring the optical performance of the final optical system.

[0048] In addition, refer to the following table 1, Figure 23 to Figure 25 As shown, under the premise that the optical system satisfies -1.92≤EP01 / CT1≤3.08, Fig.23 The defocus curve of the optical system when EP01 / CT1=2.42 and (EP23+T23) / CT3=1.90 is shown. Fig.24 The defocus curve of the optical system when EP01 / CT1=2.42 and (EP23+T23) / CT3=0.98 is shown. Fig.25 The defocus curve diagram of the optical system when EP01 / CT1=2.42 and (EP23+T23) / CT3=2.94 are satisfied is shown.

[0049] Depend on Figure 23 to Figure 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 value 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 ultimately manifests as part of the field of view without imaging or unclear imaging. When the optical system satisfies EP01 / CT1=2.42 and (EP23+T23) / CT3=2.94, the peak value 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 ultimately manifests as part of the field of view without imaging or unclear imaging. It can be seen that when -1.92≤EP01 / CT1≤3.08 is satisfied and (EP23+T23) / CT3 is controlled within the range of 1.04 to 2.86, factors such as the air gap between the second lens and the third lens in the optical system, the edge thickness of the second lens, and the center thickness of the third lens can be optimized to ensure the assembly stability of the second lens and the third lens at the front end, reduce the sensitivity of the optical performance, ensure that the risk of the final optical system being affected by the defocus curve offset is small, and reduce the risk of the defocus curve offset after assembly, thereby ensuring the optical performance of the final optical system.

[0050] Table 1

[0051]

[0052] In this embodiment, the at least one spacer further includes 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 this embodiment, 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: 0.98≤(CP1+T12) / CT1≤4.80. By constraining the above expression, the stray light improvement space between the first lens and the second lens can be guaranteed. Due to the structural limitations of the optical system, the flange position of the image side of the first lens will produce more reflected stray light. Through this expression, it can be ensured that the stray light path can be effectively intercepted by the first spacer, thereby ensuring the imaging quality. Limiting the center thickness of the first lens can also ensure that the structure of the first lens produces less stray light reflection light path.

[0054] In this 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. This expression ensures that the light can achieve an accurate transmission path through the second lens, and the edge thickness of the second lens can be limited by the above expression, which can ensure the stability of the thickness of the second lens.

[0055] In this embodiment, 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. Through this expression, by constraining the range of 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, it can be ensured that the lens barrel does not intercept the imaging light, thereby ensuring that the final imaging image of the optical system does not darken at the four corners, and at the same time limiting R1 to prevent the object side surface of the first lens from protruding from the lens barrel, and to prevent the first lens from being damaged and other defects, thereby ensuring the assembly stability of the front lens, which is conducive to improving the overall yield during the assembly process.

[0056] In this embodiment, the curvature radius 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. The expression is used to optimize the surface shape of the effective diameter of the second lens, ensuring that the optical ghost image of the optical system meets the minimum energy threshold requirement, while limiting D2s, ensuring the width of the flange surface of the second lens, ensuring the bearing range of the second lens, and facilitating the assembly stability of the second lens.

[0057] In this embodiment, the curvature radius 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. This expression can ensure that the stray light path passing through the image side surface of the second lens can be intercepted by the second spacer, thereby ensuring the imaging quality of the optical system, while ensuring the accurate transmission of light and the stability of light transmission.

[0058] In this embodiment, the axial interval EP34 between the third spacer and the fourth spacer and the center thickness CT4 of the fourth lens on the optical axis satisfy: 0.54≤CT4 / EP34≤1.76. Through this expression, the uniformity of the overall thickness of the fourth lens can be ensured, and no molding problems are generated during the molding of the fourth lens, thereby ensuring the effective diameter surface shape and appearance of the fourth lens.

[0059] In this embodiment, the air interval T34 between 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 between the third lens and the fourth lens on the optical axis through this expression, the distance between the third lens and the fourth lens is shortened, which can improve the resolution of the optical system; at the same time, the maximum axial thickness of the third spacer is guaranteed to be the minimum value, which ensures the improvement space of stray light and satisfies the structural feasibility of the optical system.

[0060] In this 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. This expression can ensure that the stray light transmitted through the object side surface of the third lens is intercepted by the third spacer, thereby achieving the purpose of improving the stray light and ensuring the final imaging quality of the optical system; limiting the inner diameter of the object side surface of the third spacer can ensure that the normal light of the optical system can pass smoothly, ensuring the light transmission, and then ensuring the imaging brightness.

[0061] In this embodiment, the outer diameter D3 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 this expression, the stray light improvement effect of the optical system is guaranteed, and the stray light can be reflected multiple times by the edge structure area of ​​the third lens, thereby reducing the stray light energy. At the same time, limiting the curvature radius of the image side surface of the third lens can also ensure that the stray light cannot be transmitted to the final imaging surface.

[0062] In this embodiment, the object side surface of the fifth lens is a convex surface, and 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 this expression, the radial bearing width of the object side surface of the fifth lens is guaranteed, and the assembly stability of the optical system is guaranteed; at the same time, it is guaranteed that the light can be accurately transmitted according to the designed path.

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

[0064] In addition, in another optional embodiment of the present application, an optical system is also provided, including a lens barrel, a lens group and at least one spacer arranged in the lens barrel, the lens group is composed of five lenses, and the five lenses are, from the object side to the image side, a first lens with negative optical focal power, a second lens with positive optical focal power, a third lens with optical focal power, a fourth lens with optical focal power and a fifth lens with optical focal power, the object side surface of the first lens is a concave surface, the image side surface of the second lens is a convex surface, and the object side surface of the third lens is a concave surface; at least one spacer includes a lens disposed between the first lens and the second lens and adjacent to the image side surface of the first lens A first spacer partially in contact with the image side surface of the second lens, a second spacer placed 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 placed between the third lens and the fourth lens and partially in contact with the image side surface of the third lens; the axial spacing EP01 between the object side end surface of the lens barrel and the first spacer and the center 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.

[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 optical 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 and the center thickness of the first lens is limited to meet performance requirements. However, when the edge thickness and center thickness of the first lens are controlled, the optical system is easily affected by factors such as the center thickness and surface shape of the first lens, resulting in assembly offset, thereby resulting in poor assembly stability, and further causing the defocus curve of the optical system to be offset after assembly, affecting the optical performance of the optical system. Therefore, the present application can ensure that the lens barrel does not intercept the imaging light, thereby ensuring that the four corners of the final imaging image of the optical system will not be darkened, by constraining -3.21≤d0s / R1≤-1.15 and by constraining the range of the ratio between the inner diameter of the object side end face of the lens barrel and the radius of curvature of the object side face of the first lens, and at the same time limiting R1 to prevent the object side face of the first lens from protruding out of the lens barrel and to prevent the first lens from being damaged or other adverse problems, thereby ensuring the assembly stability of the front-end lens and facilitating the improvement of the overall yield during the assembly process.

[0066] Of course, this embodiment may also include other parameter formulas in the above embodiment, which will not be described one by one here.

[0067] In addition, in another optional embodiment of the present application, an optical system is also provided, including a lens barrel, a lens group and at least one spacer arranged in the lens barrel, the lens group is composed of five lenses, and the five lenses are, from the object side to the image side, a first lens with negative optical focal length, a second lens with positive optical focal length, a third lens with optical focal length, a fourth lens with optical focal length and a fifth lens with optical focal length, the object side surface of the first lens is a concave surface, the image side surface of the second lens is a convex surface, and the object side surface of the third lens is a concave surface; at least one spacer includes a spacer placed between the first lens and the second lens A first spacer is placed between the second lens and in contact with the image side surface of the first lens, and a second spacer is placed between the second lens and the third lens and in contact with the image side surface of the second lens; the effective focal length f1 of the first lens and the center thickness CT1 of the first lens on the optical axis of the optical system satisfy: -25.35≤f1 / CT1≤-1.49; 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 curvature radius R2 of the image side surface of the first lens satisfy: -0.79≤(D2s-d2s) / R2≤4.67.

[0068] 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 focal length and surface shape of the five lenses, the positions of the first spacer and the second spacer, and setting the optical system to meet -25.35≤f1 / CT1≤-1.49, the relationship between the effective focal length of the first lens and the center thickness of the first lens can be constrained to be within a reasonable range, which is conducive to controlling the rationality of the center thickness of the first lens, ensuring the stability of the light deflected by the first lens, and meeting the requirements of the incident angle of the light. However, in this case, it is difficult to ensure the assembly stability of the front lens in the lens barrel. Therefore, the present application is conducive to ensuring the supporting width of the second spacer and the first lens by constraining -0.79≤(D2s-d2s) / R2≤4.67, ensuring that the contact area of ​​the two meets the requirements of assembly stability, and at the same time, it can avoid the situation where the image side of the second lens is too curved, and ensure the stability of the light trend.

[0069] Of course, this embodiment may also include other parameter formulas in the above embodiment, which will not be described one by one here.

[0070] Optionally, the optical system may further include a protective glass for protecting a photosensitive element located on the imaging surface.

[0071] The optical system in the present application may use multiple lenses, such as the five lenses mentioned above. In the present application, at least one of the mirror surfaces of each lens is an aspherical mirror surface. The characteristics of an aspherical lens are: 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 using an aspherical lens, 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, without departing from the technical solution claimed in the present application, the number of lenses constituting the optical system can be changed to obtain the various results and advantages described in this specification. For example, although five lenses are described as an example in the embodiment, the optical system is not limited to including five lenses. If necessary, the optical system may also include other numbers of lenses.

[0073] Figure 1 A schematic diagram of the dimensions of an optical system of the present application is shown. Figure 1 Parameters such as D3s, D2s, d0s, d3s, d2s, D4m, CP1, CP3, EP01, EP12, EP23, and EP34 are marked in the figure to clearly and intuitively understand the meaning of the parameters. In order to facilitate the description of the optical system and the surface shape of the specific lens, these parameters will no longer be reflected in the drawings when the specific embodiments are described later.

[0074] The following further describes examples of specific surface shapes and parameters of the optical system applicable to the above-mentioned embodiments with reference to the accompanying drawings.

[0075] It should be noted that in the following embodiment 1, there are three examples of embodiment 1-1, embodiment 1-2, and embodiment 1-3; in embodiment 2, there are three examples of embodiment 2-1, embodiment 2-2, and embodiment 2-3; and in embodiment 3, there are three examples of embodiment 3-1, embodiment 3-2, and embodiment 3-3. In the three examples of the same embodiment, the parameters such as the radius of curvature, center thickness, and the spacing distance between the lenses and the coefficients of high-order terms of the optical system of the first to fifth lenses are the same, but the parameters such as the thickness, inner diameter, and outer diameter of the lens barrel and the first to fourth spacers are different. In other words, the main structure for imaging is the same, but the auxiliary structure for imaging is different.

[0076] It should be noted that any one of the following examples 1 to 3 is applicable to all implementation methods of the present application.

[0077] Embodiment 1

[0078] like Figures 2 to 8As shown, the optical system of the first embodiment is described. Figure 2 1-1 shows a schematic diagram of the structure of the optical system of Example 1-1, Figure 3 Schematic diagram of the structure of the optical system of Example 1-2 is shown, Figure 4 A schematic diagram of the structure of the optical system of Examples 1-3 is shown.

[0079] like Figures 2 to 4 As shown, the optical system includes a lens barrel P0 and 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 which are arranged in sequence in the lens barrel P0 from the object side to the image side along the optical axis.

[0080] like Figure 2 As shown, it is a structural schematic diagram of the optical system of Example 1-1. In this example, the image side of the fourth spacer P4 is also provided with a fourth auxiliary spacer P4b. Specifically, the object side and image side of the first spacer P1 are respectively in partial contact with the image side S2 of the first lens and the object side of the first auxiliary spacer P1b, and the image side of the first auxiliary spacer P1b is partially in contact with the object side S3 of the second lens. The object side and image side of the second spacer P2 are respectively in partial contact with the image side S4 of the second lens and the object side S5 of the third lens. The object side and image side of the third spacer P3 are respectively in partial contact with the image side S6 of the third lens and the object side S7 of the fourth lens. The object side and image side of the fourth spacer P4 are respectively in partial contact with the image side S8 of the fourth lens and the object side of the fourth auxiliary spacer P4b, and the image side of the fourth auxiliary spacer P4b is partially in contact with the object side S9 of the fifth lens.

[0081] like Figure 3 , which is a schematic diagram of the structure of the optical system of Example 1-2. In this example, the fourth auxiliary spacer P4b is not provided, so the object side surface and the image side surface of the fourth spacer P4 are in partial contact with the image side surface S8 of the fourth lens and the object side surface S9 of the fifth lens, respectively. The abutment manner of the remaining spacers is the same as that of Example 1-1, and the relevant description in Example 1-1 may be referred to, and no further description is given here.

[0082] like Figure 4 , which is a schematic diagram of the structure of the optical system of Example 1-3. In this example, the abutting manner of each spacer is the same as that of Example 1-1, and the relevant description in Example 1-1 may be referred to, and will not be repeated here.

[0083] In summary, the structural parameters of the optical system of Example 1 in Example 1-1, Example 1-2, and Example 1-3 are shown in Table 2. (Unit: mm)

[0084] Table 2

[0085] Parameters / Examples 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 the first embodiment, the object side surface S1 of the first lens is a concave surface, and the image side surface S2 of the first lens is a convex surface. The object side surface S3 of the second lens is a convex surface, and the image side surface S4 of the second lens is a convex surface. The object side surface S5 of the third lens is a concave surface, and the image side surface S6 of the third lens is a concave surface. The object side surface S7 of the fourth lens is a concave surface, and the image side surface S8 of the fourth lens is a convex surface. The object side surface S9 of the fifth lens is a convex surface, and the image side surface S10 of the fifth lens is a concave surface.

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

[0088] Table 3 shows the basic structural parameters of the optical system of Example 1, wherein the units of the radius of curvature and thickness / distance are all in millimeters. In the following table, STO represents the physical aperture position.

[0089] Table 3

[0090]

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

[0092]

[0093] Wherein, x is the distance vector height from the vertex of the aspherical surface when the aspherical surface is at a height of h along the optical axis; c is the paraxial curvature of the aspherical surface, c=1 / R, that is, the paraxial curvature c is the reciprocal of the curvature radius R in Table 3 above; k is the cone coefficient; Ai is the correction coefficient of the i-th order of the aspherical surface. Table 4 below gives the high-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28, and A30 that can be used for each aspherical mirror surface S1-S10 in Example 1.

[0094] Table 4

[0095]

[0096]

[0097] Figure 5The axial chromatic aberration curve of the optical system of the first embodiment is shown, which indicates the deviation of the focusing point of light rays of different wavelengths after passing through the imaging lens. Figure 6 The astigmatism curve of the optical system of the first embodiment is shown, which represents the meridional image curvature and the sagittal image curvature. Figure 7 The distortion curve of the optical system of the first embodiment is shown, which indicates the distortion magnitude values ​​corresponding to different field angles. Figure 8 The magnification chromatic aberration curve of the optical system of the first embodiment is shown, which represents the deviation of different image heights on the imaging surface after the light passes through the optical system.

[0098] according to Figures 5 to 8 It can be seen that the optical system provided in the first embodiment can achieve good imaging quality.

[0099] Embodiment 2

[0100] like Figures 9 to 15 As shown, the optical system of the second embodiment is described. Fig. 9 2-1 shows a schematic diagram of the structure of the optical system of Example 2-1, Fig.10 2-2 shows a schematic structural diagram of the optical system of Example 2-2, Fig.11 A schematic structural diagram of the optical system of Example 2-3 is shown.

[0101] like Figures 9 to 11 As shown, the optical system includes a lens barrel P0 and 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 which are arranged in sequence in the lens barrel P0 from the object side to the image side along the optical axis.

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

[0103] like Fig.10, which is a schematic diagram of the structure of the optical system of Example 2-2. In this example, the supporting and abutting manner of each spacer is the same as that of Example 2-1, and the relevant description in Example 2-1 may be referred to, and will not be repeated here.

[0104] like Fig.11 , which is a schematic diagram of the structure of the optical system of Example 2-3. In this example, the third auxiliary spacer P3b is not provided. Therefore, the object side surface and the image side surface of the third spacer P3 are in partial contact with the image side surface S6 of the third lens and the object side surface S7 of the fourth lens, respectively. The supporting and abutting manner of the remaining spacers is the same as that of Example 2-1, and the relevant description in Example 2-1 may be referred to, and no further description is given here.

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

[0106] Table 5

[0107] Parameters / Examples 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 the second embodiment, the object side surface S1 of the first lens is a concave surface, and the image side surface S2 of the first lens is a convex surface. The object side surface S3 of the second lens is a concave surface, and the image side surface S4 of the second lens is a convex surface. The object side surface S5 of the third lens is a concave surface, and the image side surface S6 of the third lens is a convex surface. The object side surface S7 of the fourth lens is a convex surface, and the image side surface S8 of the fourth lens is a concave surface. The object side surface S9 of the fifth lens is a convex surface, and the image side surface S10 of the fifth lens is a concave surface.

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

[0110] Table 6 shows the basic structural parameters of the optical system of Example 2, wherein the units of the radius of curvature and thickness / distance are all in millimeters. In the following table, STO represents the physical aperture position.

[0111] Table 6

[0112]

[0113]

[0114] Table 7 below gives the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28, and A30 that can be used for the aspherical mirror surfaces S1-S10 in Example 2.

[0115] Table 7

[0116] Face 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 Face 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] Fig.12 The axial chromatic aberration curve of the optical system of the second embodiment is shown, which indicates the deviation of the focusing point of light rays of different wavelengths after passing through the imaging lens. Fig.13 The astigmatism curve of the optical system of the second embodiment is shown, which represents the meridional image curvature and the sagittal image curvature. Fig.14 The distortion curve of the optical system of the second embodiment is shown, which indicates the distortion magnitude values ​​corresponding to different field angles. Fig.15 The magnification chromatic aberration curve of the optical system of the second embodiment is shown, which represents the deviation of different image heights on the imaging surface after the light passes through the optical system.

[0118] according to Figures 12 to 15 It can be seen that the optical system provided in the second embodiment can achieve good imaging quality.

[0119] Embodiment 3

[0120] like Figures 16 to 22 As shown, the optical system of the third embodiment is described. Fig.16 Schematic diagram of the structure of the optical system of Example 3-1 is shown, Fig.17 Schematic diagram of the structure of the optical system of Example 3-2 is shown, Fig.18 A schematic structural diagram of the optical system of Example 3-3 is shown.

[0121] like Figures 16 to 18 As shown, 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 which are sequentially arranged in the lens barrel P0 from the object side to the image side along the optical axis. The optical system of this embodiment is a flip-chip structure, that is, the components in the lens barrel P0 are sequentially assembled into the lens barrel P0 from the object side of the lens barrel P0 in the order from the image side to the object side.

[0122] like Fig.16, which is a schematic diagram of the structure of the optical system of Example 3-1. In this example, the object side surface and image side surface of the first spacer P1 are in partial contact with the image side surface S2 of the first lens and the object side surface S3 of the second lens, respectively. The object side surface and image side surface of the second spacer P2 are in partial 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 image side surface of the third spacer P3 are in partial 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 image side surface of the fourth spacer P4 are in partial contact with the image side surface S8 of the fourth lens and the object side surface S9 of the fifth lens, respectively.

[0123] like Fig.17 , which is a schematic diagram of the structure of the optical system of Example 3-2. In this example, the abutment manner of each spacer is the same as that of Example 3-1, and reference may be made to the relevant description in Example 3-1, which will not be repeated here.

[0124] like Fig.18 , which is a schematic diagram of the structure of the optical system of Example 3-3. In this example, the supporting and abutting manner of each residual spacer is the same as that of Example 3-1, and the relevant description in Example 3-1 may be referred to, and will not be repeated here.

[0125] In summary, the structural parameters of the optical system of the third embodiment in the embodiments 3-1, 3-2 and 3-3 are shown in Table 8. (Unit: mm)

[0126] Table 8

[0127] Parameters / Examples 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 the third embodiment, the object side surface S1 of the first lens is a concave surface, and the image side surface S2 of the first lens is a concave surface. The object side surface S3 of the second lens is a convex surface, and the image side surface S4 of the second lens is a convex surface. The object side surface S5 of the third lens is a concave surface, and the image side surface S6 of the third lens is a convex surface. The object side surface S7 of the fourth lens is a concave surface, and the image side surface S8 of the fourth lens is a concave surface. The object side surface S9 of the fifth lens is a convex surface, and the image side surface S10 of the fifth lens is a convex surface.

[0129] In the third embodiment, 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 parameters of the optical system of Example 3, wherein the units of the radius of curvature and thickness / distance are all in millimeters. In the following table, STO represents the physical aperture position.

[0131] Table 9

[0132]

[0133] Table 10 below gives the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28, and A30 that can be used for each aspherical mirror surface S1-S10 in Example 3.

[0134] Table 10

[0135]

[0136]

[0137] Fig.19 The axial chromatic aberration curve of the optical system of the third embodiment is shown, which indicates the deviation of the focal point of light of different wavelengths after passing through the imaging lens. Fig. 20 The astigmatism curve of the optical system of the third embodiment is shown, which represents the meridional image plane curvature and the sagittal image plane curvature. Fig.21 The distortion curve of the optical system of the third embodiment is shown, which indicates the distortion magnitude values ​​corresponding to different field angles. Fig. 22 The magnification chromatic aberration curve of the optical system of the third embodiment is shown, which represents the deviation of different image heights on the imaging surface after the light passes through the optical system.

[0138] according to Figures 19 to 22 It can be seen that the optical system provided in the third embodiment can achieve good imaging quality.

[0139] In summary, Embodiment 1 to Embodiment 3 respectively satisfy the relationship shown in Table 11.

[0140] Table 11

[0141] Conditional / 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 |R3×N2| / 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 lengths of the lenses of the optical systems of Examples 1 to 3.

[0143] Table 12

[0144] Parameters / Examples 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, whose electronic photosensitive element can be a photosensitive coupled device (CCD) or a complementary metal oxide semiconductor element (CMOS). The imaging device can be an independent imaging device such as a digital camera, or an imaging module integrated in 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 invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0147] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0148] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned 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 numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0149] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An optical system, characterized in that: comprising a lens barrel, a lens group and at least one spacer disposed in the lens barrel, The lens group is composed of five lenses, and the five lenses are, 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 surface of the first lens is a concave surface, the image side surface of the second lens is a convex surface, and the object side surface of the third lens is a concave surface; The at least one spacer includes a first spacer disposed between the first lens and the second lens and in contact with the image side surface portion of the first lens, a second spacer disposed between the second lens and the third lens and in contact with the image side surface portion of the second lens, and a third spacer disposed between the third lens and the fourth lens and in contact with the image side surface portion of the third lens; The axial distance EP01 between the object side end surface of the lens barrel and the first spacer and the center thickness CT1 of the first lens on the optical axis of the optical system satisfy the following: 1.92≤EP01 / CT1≤3.08; An air interval T23 between the second lens and the third lens on the optical axis, an axial interval EP23 between the second spacer and the third spacer, and a center thickness CT3 of the third lens on the optical axis satisfy: 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 interval 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: 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 and the axial interval EP12 between the first spacer and the second spacer satisfy the following: 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 surface of the lens barrel and the curvature radius R1 of the object-side surface of the first lens satisfy the following relationship: -3.21≤d0s / R1≤-1.

15.

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

17.

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

59.

7. The optical system according to claim 1, characterized in that The at least one spacer also includes a fourth spacer disposed between the fourth lens and the fifth lens, and an axial interval EP34 between the third spacer and the fourth spacer and a center thickness CT4 of the fourth lens on the optical axis satisfy: 0.54≤CT4 / EP34≤1.

76.

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

55.

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

36.

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

33.

11. The optical system according to claim 1, characterized in that The at least one spacer also includes a fourth spacer placed between the fourth lens and the fifth lens, the object side surface of the fifth lens is a convex surface, and 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.

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