Optical system

Abstract

The invention provides an optical system. The optical system comprises a lens barrel, a lens group and at least one spacer, the lens group and the spacer are arranged in the lens barrel, the lens group is composed of five lenses, and the five lenses are the first lens, the second lens, the third lens, the fourth lens and the fifth lens; the at least one distance piece comprises a second distance piece, a third distance piece and a fourth distance piece; f3 / (EP2 + CT3) is greater than or equal to-3.23 and less than or equal to-3.05; f4 / EP34 is more than or equal to-17.45 and less than or equal to-13.71. The problem that a five-piece optical system in the prior art meets the requirement for imaging size control, and consequently the assembling stability is poor 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] With the continuous advancement of technology, users have higher and higher requirements for the photographic capabilities of optical systems.

[0003] At present, the prior art provides a five-lens optical system. In order to meet the requirements of image quality and image size control, it is necessary to reasonably plan the matching between lenses and spacers, especially to plan the shape of the middle lens to meet user needs to the greatest extent. However, in this case, it is easy to cause problems in the assembly of the image side lens of the middle lens, thereby affecting the overall image quality of the optical system.

[0004] That is to say, the five-element optical system in the prior art has the problem of poor assembly stability in meeting the requirements of image size control. 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 has poor assembly stability due to the requirement of image size control.

[0006] To achieve the above-mentioned purpose, 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 consists of five lenses, and the five lenses are, in order from the object side to the image side along the optical axis, a first lens, a second lens, a third lens, a fourth lens and a fifth lens; the at least one spacer comprises a second spacer located between the second lens and the third lens and in contact with the image side portion of the second lens, a third spacer located between the third lens and the fourth lens and in contact with the image side portion of the third lens, and a fourth spacer located between the fourth lens and the fifth lens and in contact with the image side portion of the fourth lens; wherein the effective focal length f3 of 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 the following relationship: -3.23≤f3 / (EP23+CT3)≤-3.05; the effective focal length f4 of the fourth lens and the axial spacing EP34 between the third spacer and the fourth spacer satisfy the following relationship: -17.45≤f4 / EP34≤-13.71.

[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 arranged in the lens barrel, wherein the lens group is composed of five lenses, and the five lenses are, in order from the object side to the image side along the optical axis, a first lens with positive focal power, a second lens with positive focal power, a third lens with negative focal power, a fourth lens with negative focal power and a fifth lens with positive focal power; and the at least one spacer comprises a second spacer located between the second lens and the third lens and in contact with the image side surface of the second lens, a spacer located between the third lens and the fourth lens and in contact with the image side surface of the third lens. A third spacer and a fourth spacer located between the fourth lens and the fifth lens and partially in contact with the image side surface of the fourth lens; wherein, the effective focal length f3 of 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: -3.23≤f3 / (EP23+CT3)≤-3.05; the outer diameter D4s of the object side surface of the fourth spacer, the inner diameter d4s of the object side surface of the fourth spacer and the curvature radius R8 of the image side surface of the fourth lens satisfy: -10.99≤R8 / (D4s-d4s)≤3.54.

[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, the lens group consisting of five lenses, which are, in order from the object side to the image side along the optical axis, a first lens with positive optical focal power, a second lens with positive optical focal power, a third lens with negative optical focal power, a fourth lens with negative optical focal power and a fifth lens with positive optical focal power; at least one spacer comprises a third spacer located between the third lens and the fourth lens and in contact with the image side portion of the third lens, and a fourth spacer located between the fourth lens and the fifth lens and in contact with the image side portion of the fourth lens; the effective focal length f3 of the third lens and the outer diameter D3s of the object side of the third spacer satisfy the following: -1.35≤f3 / D3s≤-1.04; the effective focal length f4 of the fourth lens and the maximum axial thickness CP4 of the fourth spacer satisfy the following: -17.10≤f4 / CP4≤-8.23.

[0009] Further, the lens barrel includes a first lens barrel and a second lens barrel, the second lens barrel is located on the image side of the first lens barrel, the first lens is accommodated in the first lens barrel, and the second lens, the third lens, the fourth lens and the fifth lens are all accommodated in the second lens barrel.

[0010] Furthermore, the outer diameter D10s of the object side end surface of the first lens barrel, the curvature radius R1 of the object side surface of the first lens and the center thickness CT1 of the first lens on the optical axis satisfy: 2.10≤D10s / (R1×CT1)≤2.26.

[0011] Further, the curvature radius R2 of the image side surface of the first lens, the outer diameter D10m of the image side end surface of the first lens barrel, and the inner diameter d10m of the image side end surface of the first lens barrel satisfy: 5.10≤R2 / (D10m-d10m)≤40.90.

[0012] Further, 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 D20s of the object side end surface of the second lens barrel satisfy: 1.09≤R3×N2 / D20s≤1.40.

[0013] Furthermore, an outer diameter D2s of the object side surface of the second spacer, an inner diameter d2s of the object side surface of the second spacer, and a curvature radius R4 of the image side surface of the second lens satisfy: -11.96≤R4 / (D2s-d2s)≤-3.95.

[0014] Further, the effective focal length f2 of the second lens and the axial interval EP202 between the object-side end surface of the second lens barrel and the second spacer satisfy: 7.05≤f2 / EP202≤7.78.

[0015] Further, an air interval T34 between the third lens and the fourth lens on the optical axis and an air interval T45 between the fourth lens and the fifth lens on the optical axis satisfy: 3.23≤T34 / T45≤3.68.

[0016] Furthermore, the outer diameter D20s of the object side end surface of the second lens barrel, the inner diameter d20s of the object side end surface of the second lens barrel, the outer diameter D2s of the object side surface of the second spacer, and the inner diameter d2s of the object side surface of the second spacer satisfy: 1.08≤(D20s-d20s) / (D2s-d2s)≤2.65.

[0017] Further, the curvature radius R5 of the object side surface of the third lens, the refractive index N3 of the third lens, the outer diameter D2m of the image side surface of the second spacer and the outer diameter D3s of the object side surface of the third spacer satisfy: -7.31≤R5×N3 / (D2m+D3s)≤-3.84.

[0018] Further, an inner diameter d3s of the object side surface of the third spacer, an inner diameter d3m of the image side surface of the third spacer, and a curvature radius R6 of the image side surface of the third lens satisfy: 1.59≤(d3s+d3m) / R6≤1.97.

[0019] Further, a curvature radius R7 of the object-side surface of the fourth lens and an outer diameter D3m of the image-side surface of the third spacer satisfy: -2.31≤D3m / R7≤-1.81.

[0020] Further, an outer diameter D4s of the object-side surface of the fourth spacer, an inner diameter d4s of the object-side surface of the fourth spacer, and a curvature radius R8 of the image-side surface of the fourth lens satisfy: -10.99≤R8 / (D4s-d4s)≤3.54.

[0021] Further, a center thickness CT5 of the fifth lens on the optical axis, an air interval T45 between the fourth lens and the fifth lens on the optical axis, and a maximum axial thickness CP4 of the fourth spacer satisfy: 0.86≤(CT5+T45) / CP4≤1.86.

[0022] Further, the effective focal length f3 of the third lens and the axial interval EP23 between the second spacer and the third spacer satisfy: -5.24≤f3 / EP23≤-4.95.

[0023] Furthermore, the first lens has positive focal power, the second lens has positive focal power, the third lens has negative focal power, the fourth lens has negative focal power, and the fifth lens has positive focal power; the object side surface of the first lens is convex, and the image side surface is concave; the object side surface of the second lens is convex, and the image side surface is convex; the object side surface of the third lens is concave, and the image side surface is concave; the object side surface of the fourth lens is concave, and the image side surface is convex; the object side surface of the fifth lens is convex, and the image side surface is concave.

[0024] According to the technical solution of the present invention, 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 a first lens, a second lens, a third lens, a fourth lens and a fifth lens in order from the object side to the image side along the optical axis; the at least one spacer includes a second spacer located between the second lens and the third lens and in contact with the image side portion of the second lens, a third spacer located between the third lens and the fourth lens and in contact with the image side portion of the third lens, and a fourth spacer located between the fourth lens and the fifth lens and in contact with the image side portion of the fourth lens; wherein the effective focal length f3 of 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: -3.23≤f3 / (EP23+CT3)≤-3.05; the effective focal length f4 of the fourth lens and the axial spacing EP34 between the third spacer and the fourth spacer satisfy: -17.45≤f4 / EP34≤-13.71.

[0025] The optical system of the present application is composed of a lens barrel, five lenses arranged in the lens barrel, and at least one spacer. By reasonably arranging the positions of the five lenses, the second spacer to the fourth spacer, and setting the optical system to meet -3.23≤f3 / (EP23+CT3)≤-3.05, the overall shape of the third lens can be improved while controlling the imaging size, and the assembly stability of the third lens can be improved. However, in this case, it will cause assembly problems for the fourth lens. Therefore, the present application constrains -17.45≤f4 / EP34≤-13.71. When the ratio is less than the lower limit, the shape of the fourth lens is thinner and more curved, and it is easy to break during assembly; when the ratio is greater than the upper limit, the shape of the fourth lens is thicker and flatter, and the weight is increased while affecting the refractive power of the fourth lens and the imaging quality. Therefore, the present application controls f4 / EP34 within this reasonable range, which can optimize the shape of the fourth lens, improve the assembly stability of the fourth lens, and thereby improve the overall assembly process of the optical system, while improving the overall quality of the optical system. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] 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:

[0027] Figure 1 A dimensioned diagram showing an optical system of an alternative embodiment of the present invention;

[0028] Figure 2 A schematic structural diagram of an optical system according to Embodiment 1-1 of the present invention is shown;

[0029] Figure 3 A schematic diagram showing the structure of an optical system of Embodiment 1-2 of the present invention is shown;

[0030] Figures 4 to 7 The axial chromatic aberration curve, astigmatism curve, distortion curve and magnification chromatic aberration curve of the optical system of the first embodiment of the present invention are respectively shown;

[0031] Figure 8 A schematic structural diagram of an optical system according to Embodiment 2-1 of the present invention is shown;

[0032] Fig. 9 A schematic structural diagram of an optical system according to Embodiment 2-2 of the present invention is shown;

[0033] Figures 10 to 13 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;

[0034] Fig.14A schematic structural diagram of an optical system according to Embodiment 3-1 of the present invention is shown;

[0035] Fig.15 A schematic structural diagram of an optical system according to Embodiment 3-2 of the present invention is shown;

[0036] Figures 16 to 19 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;

[0037] Fig. 20 A schematic structural diagram of an optical system according to Embodiment 4-1 of the present invention is shown;

[0038] Fig.21 A schematic structural diagram of an optical system according to Embodiment 4-2 of the present invention is shown;

[0039] Figure 22 to Figure 25 The axial chromatic aberration curve, astigmatism curve, distortion curve and magnification chromatic aberration curve of the optical system of the fourth embodiment of the present invention are respectively shown.

[0040] The above drawings include the following reference numerals:

[0041] P10, first lens barrel; P20, second lens barrel; E1, first lens; S1, object side surface of the first lens; S2, image side surface of the first lens; E2, second lens; S4, object side surface of the second lens; S5, image side surface of the second lens; E3, third lens; S6, object side surface of the third lens; S7, image side surface of the third lens; E4, fourth lens; S8, object side surface of the fourth lens; S9, image side surface of the fourth lens; E5, fifth lens; S11, object side surface of the fifth lens; S12, image side surface of the fifth lens; P2, second spacer; P3, third spacer; P4, fourth spacer. DETAILED DESCRIPTION

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] In order to solve the problem that the five-piece optical system in the prior art has poor assembly stability due to the requirement of image size control, the present invention provides an optical system.

[0049] like Figures 1 to 25As shown, in an optional embodiment of the present application, the optical system includes a lens barrel and 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 a first lens, a second lens, a third lens, a fourth lens and a fifth lens in order from the object side to the image side along the optical axis; at least one spacer includes a second spacer located between the second lens and the third lens and in contact with the image side portion of the second lens, a third spacer located between the third lens and the fourth lens and in contact with the image side portion of the third lens, and a fourth spacer located between the fourth lens and the fifth lens and in contact with the image side portion of the fourth lens; wherein the effective focal length f3 of 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: -3.23≤f3 / (EP23+CT3)≤-3.05; the effective focal length f4 of the fourth lens and the axial spacing EP34 between the third spacer and the fourth spacer satisfy: -17.45≤f4 / EP34≤-13.71.

[0050] The optical system of the present application is composed of a lens barrel, five lenses arranged in the lens barrel, and at least one spacer. By reasonably arranging the positions of the five lenses, the second spacer to the fourth spacer, and setting the optical system to meet -3.23≤f3 / (EP23+CT3)≤-3.05, the overall shape of the third lens can be improved while controlling the imaging size, and the assembly stability of the third lens can be improved. However, in this case, it will cause assembly problems for the fourth lens. Therefore, the present application constrains -17.45≤f4 / EP34≤-13.71. When the ratio is less than the lower limit, the shape of the fourth lens is thinner and more curved, and it is easy to break during assembly; when the ratio is greater than the upper limit, the shape of the fourth lens is thicker and flatter, and the weight is increased while affecting the refractive power of the fourth lens and the imaging quality. Therefore, the present application controls f4 / EP34 within this reasonable range, which can optimize the shape of the fourth lens, improve the assembly stability of the fourth lens, and thereby improve the overall assembly process of the optical system, while improving the overall quality of the optical system.

[0051] In addition, refer to Table 1 below. Table 1 shows the surface shape change of the fourth lens of the optical system of Example 1, Example 2 and Example 3 when the same load is applied. The upper and lower rows of data corresponding to the displacement in Table 1 below are the displacement data of the object side and image side of the first lens, respectively. The displacement represents the surface shape sensitivity under stress. When a force is applied to the edge structure of the fourth lens, the edge structure is deformed. Under the influence of stress, the center and edge of the fourth lens will change, resulting in a change in the surface shape pv.

[0052] It can be seen from Table 1 that when f3 / (EP23+CT3)=-3.20 and f4 / EP34=-16.12 are satisfied, the center point displacement and edge point displacement of the two side surfaces of the fourth lens are the smallest, the surface shape change is the smallest, the structural sensitivity is good, the stability is good, and the assembly stability is good. When f3 / (EP23+CT3)=-2.89 and f4 / EP34=-21.36 are satisfied, the surface shape change of the fourth lens is large, the structural sensitivity is poor, and the assembly stability is poor. When f3 / (EP23+CT3)=-5.4 and f4 / EP34=-11.52 are satisfied, the shape of the fourth lens is thinner and more curved, and it is easy to break during assembly, and the surface shape change of the fourth lens is large, the structural sensitivity is poor, and the assembly stability is poor. It can be seen that when f3 / (EP23+CT3) is in the range of -3.23 to -3.05 and f4 / EP34 is in the range of -17.45 to -13.71, the shape of the fourth lens is thicker and flatter, and the weight is increased while affecting the refractive power of the fourth lens. The deformation of the two side surfaces of the fourth lens is minimal, the structural sensitivity is optimal, and the stability is optimal. Therefore, the present application can improve the overall shape of the third lens and enhance the assembly stability of the third lens while controlling the imaging size by constraining -3.23≤f3 / (EP23+CT3)≤-3.05 and -17.45≤f4 / EP34≤-13.71. At the same time, the shape of the fourth lens can be optimized, the assembly stability of the fourth lens can be enhanced, thereby improving the overall assembly process of the optical system and improving the overall quality of the optical system.

[0053] Table 1

[0054]

[0055] In this embodiment, the lens barrel includes two lens barrels, a first lens barrel and a second lens barrel, the second lens barrel is located on the image side of the first lens barrel, the first lens is accommodated in the first lens barrel, and the second lens, the third lens, the fourth lens and the fifth lens are all accommodated in the second lens barrel. Specifically, the second spacer, the third spacer and the fourth spacer are all accommodated in the second lens barrel.

[0056] In this embodiment, the outer diameter D10s of the object side end surface of the first lens barrel, the curvature radius R1 of the object side surface of the first lens, and the center thickness CT1 of the first lens on the optical axis satisfy: 2.10≤D10s / (R1×CT1)≤2.26. By controlling the ratio of the outer diameter of the object side end surface of the first lens barrel to the product of the curvature radius of the object side surface of the first lens and the center thickness, the overall size of the first lens can be controlled while improving the curvature of the first lens, improving the shape of the first lens, and improving the assembly stability.

[0057] In this embodiment, the curvature radius R2 of the image side surface of the first lens, the outer diameter D10m of the image side end surface of the first lens barrel, and the inner diameter d10m of the image side end surface of the first lens barrel satisfy the following relationship: 5.10≤R2 / (D10m-d10m)≤40.90. By controlling the ratio of the difference between the outer diameter and the inner diameter of the image side end surface of the first lens and the first lens barrel, the curvature of the first lens can be improved while controlling the diameter of the first lens, thereby limiting the shape of the first lens and improving the assembly stability of the first lens.

[0058] 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 D20s of the object side end surface of the second lens barrel satisfy: 1.09≤R3×N2 / D20s≤1.40. By controlling this conditional expression, the shape of the second lens can be improved, the refractive power of the second lens can be enhanced, the overall size of the second lens barrel can be controlled, the overall quality can be improved, and the assembly stability can be ensured while ensuring the assembly stability.

[0059] In this embodiment, 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 R4 of the image side surface of the second lens satisfy: -11.96≤R4 / (D2s-d2s)≤-3.95. By controlling this conditional expression, the curvature of the second lens can be improved while limiting the diameter of the second lens, improving the shape and thickness ratio of the second lens, improving the overall strength of the second lens, and reducing the risk of internal reflection stray light.

[0060] In this embodiment, the effective focal length f2 of the second lens and the axial spacing EP202 between the object side end surface of the second lens barrel and the second spacer satisfy: 7.05≤f2 / EP202≤7.78. By controlling the ratio of the effective focal length of the second lens to the axial spacing between the object side end surface of the second lens barrel and the second spacer, the size of the image passing through the second lens can be improved and the position of the image can be controlled.

[0061] In this embodiment, the air interval T34 between the third lens and the fourth lens on the optical axis and the air interval T45 between the fourth lens and the fifth lens on the optical axis satisfy: 3.23≤T34 / T45≤3.68. By constraining this conditional expression, the relative positions of the three lenses can be controlled, thereby improving the field curvature of the optical system and enhancing the quality of the optical system.

[0062] In this embodiment, the outer diameter D20s of the object side end surface of the second lens barrel, the inner diameter d20s of the object side end surface of the second lens barrel, the outer diameter D2s of the object side surface of the second spacer, and the inner diameter d2s of the object side surface of the second spacer satisfy the following relationship: 1.08≤(D20s-d20s) / (D2s-d2s)≤2.65. By controlling the ratio of the difference between the outer diameter and the inner diameter of the object side end surface of the second lens barrel and the difference between the outer diameter and the inner diameter of the object side surface of the second spacer, the overall size of the optical system can be controlled, the wall thickness of the second lens barrel can be improved, the assembly step difference can be improved, and the overall quality can be improved.

[0063] In this embodiment, the radius of curvature R5 of the object side surface of the third lens, the refractive index N3 of the third lens, the outer diameter D2m of the image side surface of the second spacer, and the outer diameter D3s of the object side surface of the third spacer satisfy: -7.31≤R5×N3 / (D2m+D3s)≤-3.84. By controlling the product of the radius of curvature of the object side surface of the third lens and the refractive index of the third lens, the refractive power of the third lens can be improved while improving the curvature of the third lens, thereby improving the shape of the third lens, and improving the dispersion of the third lens, thereby improving the imaging quality; by controlling the ratio of the product to the sum of the outer diameter of the image side surface of the second spacer and the outer diameter of the object side surface of the third spacer, the outer diameter of the third lens can be limited, thereby improving the appearance of the third lens, improving the assembly stability, and improving the imaging quality.

[0064] In this embodiment, the inner diameter d3s of the object side surface of the third spacer, the inner diameter d3m of the image side surface of the third spacer, and the curvature radius R6 of the image side surface of the third lens satisfy: 1.59≤(d3s+d3m) / R6≤1.97. The curvature radius of the image side surface of the third lens reflects the curvature of the third lens, and the sum of the inner diameter of the object side surface of the third spacer and the inner diameter of the image side surface can reflect the length of the lens. By controlling the ratio of the two, the shape of the third lens can be effectively controlled, making the molding process of the third lens more reasonable, thereby improving the assembly molding problem.

[0065] In this embodiment, the curvature radius R7 of the object side surface of the fourth lens and the outer diameter D3m of the image side surface of the third spacer satisfy: -2.31≤D3m / R7≤-1.81. The curvature radius reflects the curvature of the lens, and the outer diameter of the image side surface of the third spacer reflects the diameter of the fourth lens. The ratio of the two can improve the thickness ratio of the fourth lens, make the molding of the fourth lens more reasonable, and improve the overall reliability.

[0066] In this embodiment, the outer diameter D4s of the object side surface of the fourth spacer, the inner diameter d4s of the object side surface of the fourth spacer, and the curvature radius R8 of the image side surface of the fourth lens satisfy: -10.99≤R8 / (D4s-d4s)≤3.54. The curvature radius of the image side surface of the fourth lens reflects the curvature of the fourth lens, and the difference between the outer diameter and the inner diameter of the object side surface of the fourth spacer reflects the size of the edge structure of the fourth lens, thereby balancing the size ratio of the edge structure of the fourth lens to the central optical effective part, improving the assembly stability of the fourth lens, and ensuring the reliability of the fourth lens.

[0067] It should be noted that the first to fifth lenses are composed of a central optically effective portion and an edge structure portion, wherein the edge structure portion is located on the outer peripheral side of the central optically effective portion and is arranged around the circumference of the central optically effective portion. The central optically effective portion is used for the passage of imaging light, while the edge structure portion is not used for the passage of imaging light and is used to abut against the lens barrel, an adjacent lens, or an adjacent spacer.

[0068] In this embodiment, the center thickness CT5 of the fifth lens on the optical axis, the air interval T45 between the fourth lens and the fifth lens on the optical axis, and the maximum axial thickness CP4 of the fourth spacer satisfy: 0.86≤(CT5+T45) / CP4≤1.86. By controlling the sum of the center thickness of the fifth lens and the air interval on the optical axis between the fourth lens and the fifth lens, the relative position of the fourth lens and the fifth lens and the overall proportion of the fifth lens can be adjusted. By controlling the ratio of CT5+T45 to the maximum axial thickness of the fourth spacer, the relative position relationship between the fourth lens and the fifth lens can be improved, and the assembly stability can be improved.

[0069] In this embodiment, the effective focal length f3 of the third lens and the axial spacing EP23 between the second spacer and the third spacer satisfy: -5.24≤f3 / EP23≤-4.95. By reasonably controlling the ratio of the effective focal length of the third lens to the axial spacing between the second spacer and the third spacer within this range, it is beneficial to control the overall shape of the third lens and ensure assembly stability.

[0070] In this embodiment, the first lens has positive focal power, the second lens has positive focal power, the third lens has negative focal power, the fourth lens has negative focal power, and the fifth lens has positive focal power; the object side surface of the first lens is convex, and the image side surface is concave; the object side surface of the second lens is convex, and the image side surface is convex; the object side surface of the third lens is concave, and the image side surface is concave; the object side surface of the fourth lens is concave, and the image side surface is convex; the object side surface of the fifth lens is convex, and the image side surface is concave. By reasonably constraining the focal power and surface shape of each lens, it is helpful to constrain the trend of imaging light to be transmitted according to the design, ensure that the light can transition smoothly, and help correct aberrations and ensure imaging quality.

[0071] 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.

[0072] like Figures 1 to 25 As shown, in another optional embodiment of the present application, an optical system is further provided, the optical system comprising a lens barrel, a lens group and at least one spacer arranged in the lens barrel, the lens group consisting of five lenses, the five lenses being, in order from the object side to the image side along the optical axis, a first lens having positive focal power, a second lens having positive focal power, a third lens having negative focal power, a fourth lens having negative focal power and a fifth lens having positive focal power; the at least one spacer comprising a second spacer located between the second lens and the third lens and in contact with the image side surface of the second lens, a second spacer located between the third lens and the fourth lens and in contact with the image side surface of the third lens, and a fifth lens having positive focal power. A third spacer partially contacts the side surface and a fourth spacer is located between the fourth lens and the fifth lens and partially contacts the image side surface of the fourth lens; wherein, the effective focal length f3 of 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: -3.23≤f3 / (EP23+CT3)≤-3.05; the outer diameter D4s of the object side surface of the fourth spacer, the inner diameter d4s of the object side surface of the fourth spacer and the curvature radius R8 of the image side surface of the fourth lens satisfy: -10.99≤R8 / (D4s-d4s)≤3.54.

[0073] The optical system of the present application is composed of a lens barrel, five lenses arranged in the lens barrel, and at least one spacer. By reasonably arranging the positions of the five lenses, the second spacer to the fourth spacer, and setting the optical system to satisfy -3.23≤f3 / (EP23+CT3)≤-3.05, the overall shape of the third lens can be improved while controlling the imaging size, and the assembly stability of the third lens can be improved. However, in this case, it will cause assembly problems for the fourth lens. Therefore, the present application constrains -10.99≤R8 / (D4s-d4s)≤3.54, the radius of curvature of the image side of the fourth lens reflects the degree of curvature of the fourth lens, and the difference between the outer diameter and the inner diameter of the object side of the fourth spacer reflects the size of the edge structure of the fourth lens, thereby balancing the size ratio of the edge structure of the fourth lens to the central optical effective part, improving the assembly stability of the fourth lens, and ensuring the reliability of the fourth lens.

[0074] Of course, this embodiment may also include other parameter formulas in the above embodiment, which will not be described one by one here.

[0075] like Figures 1 to 25 As shown, in another optional embodiment of the present application, an optical system is further provided, including a lens barrel and a lens group and at least one spacer arranged in the lens barrel, the lens group consisting of five lenses, and the five lenses are, in order from the object side to the image side along the optical axis, a first lens with positive optical focal power, a second lens with positive optical focal power, a third lens with negative optical focal power, a fourth lens with negative optical focal power and a fifth lens with positive optical focal power; at least one spacer includes a third spacer located between the third lens and the fourth lens and in contact with the image side portion of the third lens, and a fourth spacer located between the fourth lens and the fifth lens and in contact with the image side portion of the fourth lens; the effective focal length f3 of the third lens and the outer diameter D3s of the object side of the third spacer satisfy: -1.35≤f3 / D3s≤-1.04; the effective focal length f4 of the fourth lens and the maximum axial thickness CP4 of the fourth spacer satisfy: -17.10≤f4 / CP4≤-8.23.

[0076] The optical system of the present application is composed of a lens barrel, five lenses arranged in the lens barrel, and at least one spacer. By reasonably arranging the positions of the five lenses, the third spacer, and the fourth spacer and setting the optical system to satisfy -1.35≤f3 / D3s≤-1.04 and -17.10≤f4 / CP4≤-8.23, it is beneficial to constrain the shapes of the third lens and the fourth lens, ensure molding stability, and effectively avoid assembly problems caused by unreasonable lens size. At the same time, it is beneficial for the third spacer and the fourth spacer to effectively intercept edge stray light and ensure imaging quality.

[0077] Of course, this embodiment may also include other parameter formulas in the above embodiment, which will not be described one by one here.

[0078] 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.

[0079] 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.

[0080] Figure 1 A schematic diagram of the dimensions of an optical system of the present application is shown. Figure 1 Parameters such as D10s, d10m, D10m, D20s, d20s, D4s, d4s, d2s, D2s, D2m, D3s, CP4, EP202, EP23, EP34, d3s, d3m, and D3m are indicated 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.

[0081] 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.

[0082] It should be noted that in the following embodiment 1, there are two examples of embodiment 1-1 and embodiment 1-2, in embodiment 2, there are two examples of embodiment 2-1 and embodiment 2-2, in embodiment 3, there are two examples of embodiment 3-1 and embodiment 3-2, and in embodiment 4, there are two examples of embodiment 4-1 and embodiment 4-2. In the two examples of the same embodiment, the parameters such as the radius of curvature, center thickness, and the spacing distance between the lenses and the coefficient 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 each lens barrel and the second to fourth spacers are different. In other words, the main structure for imaging is the same, but the auxiliary structure for imaging is different.

[0083] It should be noted that any one of the following embodiments 1 to 4 is applicable to all embodiments of the present application.

[0084] Embodiment 1

[0085] like Figures 2 to 7 As 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 A schematic structural diagram of the optical system of Example 1-2 is shown.

[0086] like Figure 2 and Figure 3As shown, the optical system includes a first lens barrel P10 and a second lens barrel P20, and the second lens barrel P20 is located on the image side of the first lens barrel P10. A first lens E1 is arranged in the first lens barrel P10. 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 are arranged in sequence from the object side to the image side in the second lens barrel P20.

[0087] like Figure 2 , which 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 element. The object side surface and the image side surface of the second spacer P2 are respectively in contact with the image side surface S5 of the second lens and the object side surface S6 of the third lens. The object side surface and the image side surface of the third spacer P3 are respectively in contact with the image side surface S7 of the third lens and the object side surface S8 of the fourth lens. The object side surface and the image side surface of the fourth spacer P4 are respectively in contact with the image side surface S9 of the fourth lens and the object side surface of the fourth auxiliary spacer element, and the image side surface of the fourth auxiliary spacer element is in contact with the object side surface S11 of the fifth lens.

[0088] like Figure 3 , which is a schematic diagram of the structure of the optical system of Example 1-2. In this example, the supporting and 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.

[0089] In summary, the structural parameters of the optical system of Example 1 under Example 1-1 and Example 1-2 are shown in Table 2. (Unit: mm)

[0090] Table 2

[0091]

[0092]

[0093] In the first embodiment, the object side surface S1 of the first lens is a convex surface, and the image side surface S2 of the first lens is a concave surface. The object side surface S4 of the second lens is a convex surface, and the image side surface S5 of the second lens is a convex surface. The object side surface S6 of the third lens is a concave surface, and the image side surface S7 of the third lens is a concave surface. The object side surface S8 of the fourth lens is a concave surface, and the image side surface S9 of the fourth lens is a convex surface. The object side surface S11 of the fifth lens is a convex surface, and the image side surface S12 of the fifth lens is a concave surface.

[0094] In the first embodiment, the effective focal length f1 of the first lens is 750.00 mm, the effective focal length f2 of the second lens is 6.15 mm, the effective focal length f3 of the third lens is -6.96 mm, the effective focal length f4 of the fourth lens is -14.88 mm, and the effective focal length f5 of the fifth lens is 8.22 mm.

[0095] 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, S3 and S10 are the positions of physical apertures, indicating physical light blocking, such as a lens barrel or a spacer.

[0096] Table 3

[0097]

[0098]

[0099] 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:

[0100]

[0101] Wherein, x is the distance vector height from the vertex of the aspheric surface when the aspheric surface is at a height of h along the optical axis; c is the paraxial curvature of the aspheric surface, c=1 / R, that is, the paraxial curvature c is the reciprocal of the curvature radius R in Table 1 above; k is the cone coefficient; Ai is the correction coefficient of the i-th order of the aspheric surface. Table 4 below gives the high-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 that can be used for each aspheric mirror surface S1-S12 in Example 1.

[0102] Table 4

[0103] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 S1 -3.0693E-03 -1.0631E-04 1.6983E-05 -4.4463E-06 8.4778E-07 -9.2432E-08 5.8116E-09 -1.9674E-10 2.7758E-12 S2 -4.0225E-03 -8.3837E-05 8.9203E-06 -2.1157E-06 5.6806E-07 -7.6372E-08 5.5262E-09 -2.0814E-10 3.2072E-12 S4 1.0258E-03 1.4702E-03 -2.4801E-03 1.6753E-03 -8.2947E-04 2.7765E-04 -5.8536E-05 6.8609E-06 -3.3465E-07 S5 2.4700E-03 2.7975E-02 -3.6400E-02 2.4211E-02 -9.8270E-03 2.5384E-03 -4.1269E-04 3.8852E-05 -1.6158E-06 S6 -2.6595E-02 3.6444E-02 -4.1181E-02 2.7610E-02 -1.1190E-02 2.8262E-03 -4.4159E-04 3.9641E-05 -1.5795E-06 S7 -2.8448E-02 1.2974E-02 -1.4512E-02 1.2225E-02 -6.1695E-03 1.9802E-03 -4.0721E-04 4.9153E-05 -2.6208E-06 S8 7.2918E-02 -4.3540E-02 2.7498E-02 -1.2454E-02 3.9475E-03 -7.4590E-04 5.3152E-05 4.9681E-06 -7.8079E-07 S9 -3.2854E-02 5.5669E-02 -5.2727E-02 3.5840E-02 -1.6439E-02 4.9409E-03 -9.2868E-04 9.8858E-05 -4.5437E-06 S11 -7.7915E-02 7.0796E-02 -5.9597E-02 3.7858E-02 -1.6662E-02 4.8685E-03 -8.9653E-04 9.3921E-05 -4.2606E-06 S12 -1.1193E-02 -1.9532E-03 6.3887E-03 -5.7420E-03 3.1127E-03 -1.0724E-03 2.2913E-04 -2.7709E-05 1.4508E-06

[0104] Figure 4 The 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 optical system. Figure 5 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 6 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 7 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.

[0105] according to Figures 4 to 7 It can be seen that the optical system provided in the first embodiment can achieve good imaging quality.

[0106] Embodiment 2

[0107] like Figures 8 to 13 As shown, the optical system of the second embodiment is described. Figure 82-1 shows a schematic diagram of the structure of the optical system of Example 2-1, Fig. 9 A schematic structural diagram of the optical system of Example 2-2 is shown.

[0108] like Figure 8 and Fig. 9 As shown, the optical system includes a first lens barrel P10 and a second lens barrel P20, and the second lens barrel P20 is located on the image side of the first lens barrel P10. A first lens E1 is arranged in the first lens barrel P10. 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 are arranged in sequence from the object side to the image side in the second lens barrel P20.

[0109] like Figure 8 , which is a structural schematic diagram of the optical system of Example 2-1. In this example, the image side of the fourth spacer P4 is also provided with a fourth auxiliary spacer element. The object side surface and the image side surface of the second spacer P2 are respectively in contact with the image side surface S5 of the second lens and the object side surface S6 of the third lens. The object side surface and the image side surface of the third spacer P3 are respectively in contact with the image side surface S7 of the third lens and the object side surface S8 of the fourth lens. The object side surface and the image side surface of the fourth spacer P4 are respectively in contact with the image side surface S9 of the fourth lens and the object side surface of the fourth auxiliary spacer element, and the image side surface of the fourth auxiliary spacer element is in contact with the object side surface S11 of the fifth lens.

[0110] like Fig. 9 , 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.

[0111] In summary, the structural parameters of the optical system of the second embodiment in the embodiment 2-1 and the embodiment 2-2 are shown in Table 5. (Unit: mm)

[0112] Table 5

[0113] Parameters / Examples 2-1 2-2 d10m(mm) 8.334 8.334 D10s(mm) 8.623 8.623 D10m(mm) 8.583 8.987 d20s(mm) 4.840 4.840 D20s(mm) 6.235 6.235 d2s(mm) 4.263 4.263 D2s(mm) 4.992 5.458 D2m(mm) 4.992 5.458 D3s(mm) 5.092 5.558 d4s(mm) 4.336 4.181 D4s(mm) 4.857 5.330 EP202(mm) 0.803 0.803 EP23(mm) 1.320 1.322 EP34(mm) 0.850 0.852 CP4(mm) 1.801 1.083 d3s(mm) 4.802 4.802 d3m(mm) 4.802 4.802 D3m(mm) 5.092 5.558

[0114] In the second embodiment, the object side surface S1 of the first lens is a convex surface, and the image side surface S2 of the first lens is a concave surface. The object side surface S4 of the second lens is a convex surface, and the image side surface S5 of the second lens is a convex surface. The object side surface S6 of the third lens is a concave surface, and the image side surface S7 of the third lens is a concave surface. The object side surface S8 of the fourth lens is a concave surface, and the image side surface S9 of the fourth lens is a convex surface. The object side surface S11 of the fifth lens is a convex surface, and the image side surface S12 of the fifth lens is a concave surface.

[0115] In the second embodiment, the effective focal length f1 of the first lens is 600.00 mm, the effective focal length f2 of the second lens is 6.25 mm, the effective focal length f3 of the third lens is -6.89 mm, the effective focal length f4 of the fourth lens is -14.83 mm, and the effective focal length f5 of the fifth lens is 7.92 mm.

[0116] 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, S3 and S10 are the positions of physical apertures, indicating physical light blocking, such as a lens barrel or a spacer.

[0117] Table 6

[0118]

[0119] Table 7 below gives the high-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 that can be used for the aspherical mirror surfaces S1-S12 in Example 2.

[0120] Table 7

[0121] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 S1 -3.0071E-03 -1.6918E-04 4.4472E-05 -1.1237E-05 1.9262E-06 -2.0254E-07 1.2770E-08 -4.4359E-10 6.5262E-12 S2 -3.9280E-03 -1.7645E-04 5.2011E-05 -1.3511E-05 2.4868E-06 -2.8310E-07 1.9285E-08 -7.2187E-10 1.1423E-11 S4 2.0887E-03 -1.9363E-04 -6.9021E-04 5.3554E-04 -3.9889E-04 1.8059E-04 -4.6496E-05 6.2208E-06 -3.3215E-07 S5 1.7401E-02 -1.7698E-02 2.3307E-02 -1.8548E-02 8.6748E-03 -2.4567E-03 4.1261E-04 -3.7580E-05 1.4247E-06 S6 -9.1391E-03 -2.4149E-02 4.0562E-02 -3.1770E-02 1.4739E-02 -4.2223E-03 7.3051E-04 -6.9708E-05 2.8093E-06 S7 -1.4557E-02 -3.2190E-02 4.1556E-02 -2.4221E-02 7.6654E-03 -1.1794E-03 1.3228E-05 2.0396E-05 -1.9317E-06 S8 9.3445E-02 -9.8386E-02 8.8167E-02 -4.8381E-02 1.6252E-02 -3.1809E-03 3.0585E-04 -3.9791E-06 -1.0459E-06 S9 -1.0438E-02 -4.6200E-03 2.0078E-02 -1.5661E-02 6.6330E-03 -1.7132E-03 2.7275E-04 -2.4968E-05 1.0229E-06 S11 -6.2651E-02 3.0032E-02 -7.8746E-03 -4.9598E-04 1.2658E-03 -4.8401E-04 9.4654E-05 -9.8586E-06 4.3668E-07 S12 -1.0030E-02 -1.4856E-03 3.3600E-03 -1.2216E-03 -3.1634E-04 4.4991E-04 -1.7075E-04 3.0007E-05 -2.0845E-06

[0122] Fig.10 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 of different wavelengths after passing through the optical system. Fig.11 The astigmatism curve of the optical system of the second embodiment is shown, which represents the meridional image plane curvature and the sagittal image plane curvature. Fig.12 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.13 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.

[0123] according to Figures 10 to 13 It can be seen that the optical system provided in the second embodiment can achieve good imaging quality.

[0124] Embodiment 3

[0125] like Figures 14 to 19 As shown, the optical system of the third embodiment is described. Fig.14 Schematic diagram of the structure of the optical system of Example 3-1 is shown, Fig.15 A schematic structural diagram of the optical system of Example 3-2 is shown.

[0126] like Fig.14 and Fig.15As shown, the optical system includes a first lens barrel P10 and a second lens barrel P20, and the second lens barrel P20 is located on the image side of the first lens barrel P10. A first lens E1 is arranged in the first lens barrel P10. 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 are arranged in sequence from the object side to the image side in the second lens barrel P20.

[0127] like Fig.14 , which is a schematic diagram of the structure of the optical system of Example 3-1. In this example, the image side of the fourth spacer P4 is also provided with a fourth auxiliary spacer element. The object side surface and the image side surface of the second spacer P2 are respectively in contact with the image side surface S5 of the second lens and the object side surface S6 of the third lens. The object side surface and the image side surface of the third spacer P3 are respectively in contact with the image side surface S7 of the third lens and the object side surface S8 of the fourth lens. The object side surface and the image side surface of the fourth spacer P4 are respectively in contact with the image side surface S9 of the fourth lens and the object side surface of the fourth auxiliary spacer element, and the image side surface of the fourth auxiliary spacer element is in contact with the object side surface S11 of the fifth lens.

[0128] like Fig.15 , 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.

[0129] In summary, the structural parameters of the optical system of the third embodiment in the embodiments 3-1 and 3-2 are shown in Table 8. (Unit: mm)

[0130] Table 8

[0131]

[0132]

[0133] In the third embodiment, the object side surface S1 of the first lens is convex, and the image side surface S2 of the first lens is concave. The object side surface S4 of the second lens is convex, and the image side surface S5 of the second lens is convex. The object side surface S6 of the third lens is concave, and the image side surface S7 of the third lens is concave. The object side surface S8 of the fourth lens is concave, and the image side surface S9 of the fourth lens is convex. The object side surface S11 of the fifth lens is convex, and the image side surface S12 of the fifth lens is concave.

[0134] In Example 3, the effective focal length f1 of the first lens is 550.00 mm, the effective focal length f2 of the second lens is 6.08 mm, the effective focal length f3 of the third lens is -6.84 mm, the effective focal length f4 of the fourth lens is -13.50 mm, and the effective focal length f5 of the fifth lens is 7.91 mm.

[0135] 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, S3 and S10 are the positions of physical apertures, indicating physical light blocking, such as a lens barrel or a spacer.

[0136] Table 9

[0137]

[0138] Table 10 below gives the high-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 that can be used for the aspheric mirror surfaces S1-S12 in Example 3.

[0139] Table 10

[0140] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 S1 -3.0293E-03 -1.2939E-04 2.9943E-05 -7.4813E-06 1.2942E-06 -1.3608E-07 8.5306E-09 -2.9359E-10 4.2677E-12 S2 -3.9311E-03 -1.3817E-04 3.7444E-05 -9.4642E-06 1.7409E-06 -1.9731E-07 1.3326E-08 -4.9315E-10 7.6991E-12 S4 1.6815E-03 -4.4357E-04 -2.4399E-04 2.4213E-04 -2.6772E-04 1.3961E-04 -3.7613E-05 5.0583E-06 -2.6688E-07 S5 1.4469E-02 -1.3125E-02 2.0097E-02 -1.7778E-02 8.9000E-03 -2.6433E-03 4.6123E-04 -4.3590E-05 1.7222E-06 S6 -1.1766E-02 -1.5366E-02 3.2394E-02 -2.8497E-02 1.4353E-02 -4.3677E-03 7.9136E-04 -7.8434E-05 3.2707E-06 S7 -1.9586E-02 -1.9987E-02 3.0938E-02 -1.9565E-02 6.3508E-03 -8.2486E-04 -8.2692E-05 3.6946E-05 -3.1045E-06 S8 8.2181E-02 -7.7000E-02 7.0406E-02 -3.9882E-02 1.3417E-02 -2.3820E-03 1.2034E-04 2.3344E-05 -2.7879E-06 S9 -1.5776E-02 8.8991E-03 5.6731E-03 -6.4263E-03 2.6826E-03 -5.5655E-04 4.9724E-05 3.6117E-07 -2.4975E-07 S11 -6.3589E-02 3.5559E-02 -1.5749E-02 5.3780E-03 -1.4794E-03 3.4906E-04 -6.5119E-05 7.7404E-06 -4.1117E-07 S12 -9.5201E-03 -2.3638E-03 4.9873E-03 -3.4047E-03 1.3752E-03 -3.3790E-04 4.8791E-05 -3.8037E-06 1.3078E-07

[0141] Fig.16 The axial chromatic aberration curve of the optical system of the third embodiment is shown, which indicates the deviation of the focusing point of light of different wavelengths after passing through the optical system. Fig.17 The astigmatism curve of the optical system of the third embodiment is shown, which represents the meridional image curvature and the sagittal image curvature. Fig.18 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.19 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.

[0142] according to Figures 16 to 19 It can be seen that the optical system provided in the third embodiment can achieve good imaging quality.

[0143] Embodiment 4

[0144] like Figure 20 to Figure 25 As shown, the optical system of the fourth embodiment is described. Fig. 20 4-1 shows a schematic diagram of the structure of the optical system of Example 4-1, Fig.21 A schematic structural diagram of the optical system of Example 4-2 is shown.

[0145] like Fig. 20 and Fig.21 As shown, the optical system includes a first lens barrel P10 and a second lens barrel P20, and the second lens barrel P20 is located on the image side of the first lens barrel P10. A first lens E1 is arranged in the first lens barrel P10. 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 are arranged in sequence from the object side to the image side in the second lens barrel P20.

[0146] like Fig. 20 , which is a structural schematic diagram of the optical system of Example 4-1. In this example, the image side of the fourth spacer P4 is also provided with a fourth auxiliary spacer element. The object side surface and the image side surface of the second spacer P2 are respectively in contact with the image side surface S5 of the second lens and the object side surface S6 of the third lens. The object side surface and the image side surface of the third spacer P3 are respectively in contact with the image side surface S7 of the third lens and the object side surface S8 of the fourth lens. The object side surface and the image side surface of the fourth spacer P4 are respectively in contact with the image side surface S9 of the fourth lens and the object side surface of the fourth auxiliary spacer element, and the image side surface of the fourth auxiliary spacer element is in contact with the object side surface S11 of the fifth lens.

[0147] like Fig.21 , which is a schematic diagram of the structure of the optical system of Example 4-2. In this example, the supporting and abutting manner of each spacer is the same as that of Example 4-1, and the relevant description in Example 4-1 may be referred to, and will not be repeated here.

[0148] In summary, the structural parameters of the optical system of the fourth embodiment under the embodiment 4-1 and the embodiment 4-2 are shown in Table 11. (Unit: mm)

[0149] Table 11

[0150]

[0151] In the fourth embodiment, the object side surface S1 of the first lens is convex, and the image side surface S2 of the first lens is concave. The object side surface S4 of the second lens is convex, and the image side surface S5 of the second lens is convex. The object side surface S6 of the third lens is concave, and the image side surface S7 of the third lens is concave. The object side surface S8 of the fourth lens is concave, and the image side surface S9 of the fourth lens is convex. The object side surface S11 of the fifth lens is convex, and the image side surface S12 of the fifth lens is concave.

[0152] In the fourth embodiment, the effective focal length f1 of the first lens is 500.00 mm, the effective focal length f2 of the second lens is 6.21 mm, the effective focal length f3 of the third lens is -6.95 mm, the effective focal length f4 of the fourth lens is -14.35 mm, and the effective focal length f5 of the fifth lens is 8.00 mm.

[0153] Table 12 shows the basic structural parameters of the optical system of Example 4, wherein the units of the radius of curvature and thickness / distance are all in millimeters. In the following table, S3 and S10 are the positions of physical apertures, indicating physical light blocking, such as a lens barrel or a spacer.

[0154] Table 12

[0155]

[0156]

[0157] Table 13 below gives the high-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 that can be used for the aspheric mirror surfaces S1-S12 in Example 4.

[0158] Table 13

[0159] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 S1 -2.7895E-03 -1.9293E-04 5.2834E-05 -1.3015E-05 2.1778E-06 -2.2822E-07 1.4536E-08 -5.1444E-10 7.7505E-12 S2 -3.5697E-03 -1.9740E-04 5.6221E-05 -1.3690E-05 2.3815E-06 -2.6291E-07 1.7678E-08 -6.6054E-10 1.0504E-11 S4 1.5625E-03 -8.2288E-04 3.1657E-04 -3.9891E-04 1.3456E-04 -7.8234E-06 -7.1243E-06 1.8132E-06 -1.2991E-07 S5 8.2847E-03 7.8675E-03 -8.4131E-03 3.0139E-03 -1.6220E-04 -2.3656E-04 8.1472E-05 -1.0931E-05 5.4422E-07 S6 -2.1203E-02 1.8081E-02 -1.4332E-02 6.8192E-03 -1.6354E-03 6.5873E-05 5.6409E-05 -1.1700E-05 7.2091E-07 S7 -2.8003E-02 1.0981E-02 -9.6528E-03 6.4411E-03 -2.1111E-03 2.0727E-04 5.0782E-05 -1.3580E-05 8.5965E-07 S8 6.7686E-02 -3.0978E-02 1.1562E-02 -8.1192E-04 -8.5748E-04 2.7749E-04 -2.5978E-05 -1.1997E-07 4.6213E-08 S9 -3.7473E-02 6.4961E-02 -6.4182E-02 4.4804E-02 -2.0906E-02 6.3609E-03 -1.2079E-03 1.2984E-04 -6.0292E-06 S11 -7.7915E-02 7.0796E-02 -5.9597E-02 3.7858E-02 -1.6662E-02 4.8685E-03 -8.9653E-04 9.3921E-05 -4.2606E-06 S12 -1.1193E-02 -1.9532E-03 6.3887E-03 -5.7420E-03 3.1127E-03 -1.0724E-03 2.2913E-04 -2.7709E-05 1.4508E-06

[0160] Fig. 22 The axial chromatic aberration curve of the optical system of the fourth embodiment is shown, which indicates the deviation of the focusing point of light of different wavelengths after passing through the optical system. Fig.23 The astigmatism curve of the optical system of Example 4 is shown, which represents the meridional image plane curvature and the sagittal image plane curvature. Fig.24 The distortion curve of the optical system of the fourth embodiment is shown, which represents the distortion magnitude values ​​corresponding to different field angles. Fig.25 The magnification chromatic aberration curve of the optical system of Example 4 is shown, which represents the deviation of different image heights on the imaging surface after the light passes through the optical system.

[0161] according to Figure 22 to Figure 25 It can be seen that the optical system provided in the fourth embodiment can achieve good imaging quality.

[0162] In summary, Embodiments 1 to 4 respectively satisfy the relationships shown in Table 14.

[0163] Table 14

[0164]

[0165]

[0166] Table 15 shows the effective focal lengths of the lenses of the optical systems of Examples 1 to 4.

[0167] Table 15

[0168] Parameters / Examples one two three Four f1(mm) 750.00 600.00 550.00 500.00 f2(mm) 6.15 6.25 6.08 6.21 f3(mm) -6.96 -6.89 -6.84 -6.95 f4(mm) -14.88 -14.83 -13.50 -14.35 f5(mm) 8.22 7.92 7.91 8.00

[0169] 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.

[0170] 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.

[0171] 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.

[0172] 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.

[0173] 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 sequentially a first lens, a second lens, a third lens, a fourth lens and a fifth lens from the object side to the image side along the optical axis; The at least one spacer includes a second spacer located between the second lens and the third lens and in contact with the image side surface portion of the second lens, a third spacer located between the third lens and the fourth lens and in contact with the image side surface portion of the third lens, and a fourth spacer located between the fourth lens and the fifth lens and in contact with the image side surface portion of the fourth lens; The effective focal length f3 of 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: -3.23≤f3 / (EP23+CT3)≤-3.05; the effective focal length f4 of the fourth lens and the axial interval EP34 between the third spacer and the fourth spacer satisfy the following: -17.45≤f4 / EP34≤-13.

71.

2. The optical system according to claim 1, characterized in that The lens barrel includes a first lens barrel and a second lens barrel, the second lens barrel is located on the image side of the first lens barrel, the first lens is accommodated in the first lens barrel, and the second lens, the third lens, the fourth lens and the fifth lens are all accommodated in the second lens barrel.

3. The optical system according to claim 2, characterized in that The outer diameter D10s of the object-side end surface of the first lens barrel, the curvature radius R1 of the object-side surface of the first lens, and the center thickness CT1 of the first lens on the optical axis satisfy: 2.10≤D10s / (R1×CT1)≤2.

26.

4. The optical system according to claim 2, characterized in that The curvature radius R2 of the image side surface of the first lens, the outer diameter D10m of the image side end surface of the first lens barrel, and the inner diameter d10m of the image side end surface of the first lens barrel satisfy the following relationship: 5.10≤R2 / (D10m-d10m)≤40.

90.

5. The optical system according to claim 2, characterized in that 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 D20s of the object-side end surface of the second lens barrel satisfy the following: 1.09≤R3×N2 / D20s≤1.

40.

6. The optical system according to claim 1, characterized in that 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 R4 of the image side surface of the second lens satisfy: -11.96≤R4 / (D2s-d2s)≤-3.

95.

7. The optical system according to claim 2, characterized in that The effective focal length f2 of the second lens and the axial distance EP202 between the object-side end surface of the second lens barrel and the second spacer satisfy the following: 7.05≤f2 / EP202≤7.

78.

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 an air interval T45 between the fourth lens and the fifth lens on the optical axis satisfy the following: 3.23≤T34 / T45≤3.

68.

9. The optical system according to claim 2, characterized in that The outer diameter D20s of the object side end surface of the second lens barrel, the inner diameter d20s of the object side end surface of the second lens barrel, the outer diameter D2s of the object side surface of the second spacer, and the inner diameter d2s of the object side surface of the second spacer satisfy the following relationship: 1.08≤(D20s-d20s) / (D2s-d2s)≤2.

65.

10. The optical system according to claim 1, characterized in that The curvature radius R5 of the object side surface of the third lens, the refractive index N3 of the third lens, the outer diameter D2m of the image side surface of the second spacer and the outer diameter D3s of the object side surface of the third spacer satisfy: -7.31≤R5×N3 / (D2m+D3s)≤-3.

84.

11. The optical system according to claim 1, characterized in that An inner diameter d3s of the object side surface of the third spacer, an inner diameter d3m of the image side surface of the third spacer, and a curvature radius R6 of the image side surface of the third lens satisfy the following relationship: 1.59≤(d3s+d3m) / R6≤1.

97.

12. The optical system according to claim 1, characterized in that A curvature radius R7 of the object-side surface of the fourth lens and an outer diameter D3m of the image-side surface of the third spacer satisfy the following: -2.31≤D3m / R7≤-1.

81.

13. The optical system according to claim 1, characterized in that The outer diameter D4s of the object-side surface of the fourth spacer, the inner diameter d4s of the object-side surface of the fourth spacer, and the curvature radius R8 of the image-side surface of the fourth lens satisfy: -10.99≤R8 / (D4s-d4s)≤3.

54.

14. The optical system according to claim 1, characterized in that A center thickness CT5 of the fifth lens on the optical axis, an air interval T45 between the fourth lens and the fifth lens on the optical axis, and a maximum axial thickness CP4 of the fourth spacer satisfy the following: 0.86≤(CT5+T45) / CP4≤1.

86.

15. The optical system according to claim 1, characterized in that The effective focal length f3 of the third lens and the axial interval EP23 between the second spacer and the third spacer satisfy: -5.24≤f3 / EP23≤-4.

95.

16. The optical system according to any one of claims 1 to 15, characterized in that The first lens has positive optical power, the second lens has positive optical power, the third lens has negative optical power, the fourth lens has negative optical power, and the fifth lens has positive optical power; The object side surface of the first lens is convex, and the image side surface is concave; the object side surface of the second lens is convex, and the image side surface is convex; the object side surface of the third lens is concave, and the image side surface is concave; the object side surface of the fourth lens is concave, and the image side surface is convex; the object side surface of the fifth lens is convex, and the image side surface is concave.

Images