Optical system

Abstract

The utility model provides an optical system. The optical system comprises a lens barrel, a lens group and at least one spacer, 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 five-piece type optical system solves the problem that a five-piece type optical system in the prior art meets the requirement for controlling the imaging size, so that the assembling stability is poor.

Description

Technical Field

[0001] This utility model relates to the field of optical imaging equipment technology, and more specifically, to an optical system. Background Technology

[0002] With the continuous advancement of technology, users have increasingly higher requirements for the photographic capabilities of optical systems.

[0003] Currently, existing technology provides a five-element optical system. To meet the requirements of image quality and image size control, it is necessary to rationally plan the matching between lenses and spacers, especially the shape of the intermediate lens to best meet user needs. However, in this case, problems may easily occur in the assembly of the image-side lens of the intermediate lens, thereby affecting the overall image quality of the optical system.

[0004] In other words, the existing five-element optical system suffers from poor assembly stability due to the inability to meet the requirements of image size control. Utility Model Content

[0005] The main objective of this invention is to provide an optical system that solves the problem of poor assembly stability caused by the five-element optical system in the prior art, which fails to meet the requirements for controlling the image size.

[0006] To achieve the above objectives, according to one aspect of the present invention, an optical system is provided, comprising a lens barrel and a lens group disposed within the lens barrel, and at least one spacer. The lens group consists of five lenses, which are sequentially arranged along the optical axis from the object side to the image side as a first lens, a second lens, a third lens, a fourth lens, and a fifth lens. The at least one spacer includes a second spacer located between the second and third lenses and in contact with the image-side surface of the second lens, a third spacer located between the third and fourth lenses and in contact with the image-side surface of the third lens, and a fourth spacer located between the fourth and fifth lenses and in contact with the image-side surface of the fourth lens. The effective focal length f3 of the third lens, the axial spacing EP23 between the second and third spacers, and the center thickness CT3 of the third lens on the optical axis satisfy the following condition: -3.23 ≤ f3 / (EP23+CT3) ≤ -3.05. The effective focal length f4 of the fourth lens and the axial spacing EP34 between the third and fourth spacers satisfy the following condition: -17.45 ≤ f4 / EP34 ≤ -13.71.

[0007] According to another aspect of the present invention, an optical system is provided, including a lens barrel, a lens group disposed in the lens barrel, and at least one spacer. The lens group consists of five lenses, which are arranged sequentially along the optical axis from the object side to the image side as a first lens with positive optical power, a second lens with positive optical power, a third lens with negative optical power, a fourth lens with negative optical power, and a fifth lens with positive optical power. The at least one spacer includes a second spacer located between the second and third lenses and in contact with the image-side surface of the second lens, and a spacer located between the third and fourth lenses and in contact with the image-side surface of the third lens. The third spacer and the fourth spacer located between the fourth and fifth lenses and 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 and third spacers 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 radius of curvature 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, including a lens barrel and a lens group disposed in the lens barrel and at least one spacer. The lens group consists of five lenses, which are arranged sequentially along the optical axis from the object side to the image side as a first lens with positive optical power, a second lens with positive optical power, a third lens with negative optical power, a fourth lens with negative optical power, and a fifth lens with positive optical power. The at least one spacer includes a third spacer located between the third and fourth lenses and in contact with the image-side surface of the third lens, and a fourth spacer located between the fourth and fifth lenses and in contact with the image-side surface of the fourth lens. The effective focal length f3 of the third lens and the outer diameter D3s of the object side surface of the third spacer satisfy the following condition: -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 condition: -17.10≤f4 / CP4≤-8.23.

[0009] Furthermore, the lens tube includes a first lens tube and a second lens tube, the second lens tube being located on the image side of the first lens tube, the first lens being housed in the first lens tube, and the second lens, third lens, fourth lens and fifth lens being housed in the second lens tube.

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

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

[0012] Furthermore, the radius of curvature R3 of the object side surface of the second lens, the refractive index N2 of the second lens, and the outer diameter D20s of the object side end face of the second lens barrel satisfy the following relationship: 1.09≤R3×N2 / D20s≤1.40.

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

[0014] Furthermore, the effective focal length f2 of the second lens and the axial distance EP202 between the object-side end face of the second lens barrel and the second spacer satisfy the following condition: 7.05≤f2 / EP202≤7.78.

[0015] Furthermore, the air gap T34 between the third and fourth lenses on the optical axis and the air gap T45 between the fourth and fifth lenses on the optical axis satisfy the following condition: 3.23 ≤ T34 / T45 ≤ 3.68.

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

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

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

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

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

[0021] Furthermore, the central thickness CT5 of the fifth lens on the optical axis, the air gap T45 between the fourth and fifth lenses on the optical axis, and the maximum axial thickness CP4 of the fourth spacer satisfy the following: 0.86≤(CT5+T45) / CP4≤1.86.

[0022] Furthermore, the effective focal length f3 of the third lens satisfies the following relationship with the axial spacing EP23 between the second and third spacers: -5.24≤f3 / EP23≤-4.95.

[0023] Furthermore, 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.

[0024] According to the technical solution of this utility model, the optical system includes a lens barrel, a lens group disposed in the lens barrel, and at least one spacer. The lens group consists of five lenses, which are arranged sequentially from the object side to the image side along the optical axis as a first lens, a second lens, a third lens, a fourth lens, and a fifth lens. The at least one spacer includes a second spacer located between the second and third lenses and in contact with the image-side surface of the second lens, a third spacer located between the third and fourth lenses and in contact with the image-side surface of the third lens, and a fourth spacer located between the fourth and fifth lenses and in contact with the image-side surface of the fourth lens. The effective focal length f3 of the third lens, the axial spacing EP23 between the second and third spacers, and the center thickness CT3 of the third lens on the optical axis satisfy the following condition: -3.23≤f3 / (EP23+CT3)≤-3.05. The effective focal length f4 of the fourth lens and the axial spacing EP34 between the third and fourth spacers satisfy the following condition: -17.45≤f4 / EP34≤-13.71.

[0025] The optical system of this application consists of a lens barrel, five lenses disposed within the lens barrel, and at least one spacer. By rationally arranging the positions of the five lenses and the second to fourth spacers, and ensuring that the optical system satisfies -3.23 ≤ f3 / (EP23+CT3) ≤ -3.05, the overall shape of the third lens can be improved while controlling the image size, thus enhancing the assembly stability of the third lens. However, this leads to assembly problems with the fourth lens. Therefore, this application constrains the fourth lens to -17.45 ≤ f4 / EP34 ≤ -13.71. When this ratio is less than the lower limit, the fourth lens becomes thinner and more curved, making it prone to breakage during assembly; when this ratio is greater than the upper limit, the fourth lens becomes thicker and flatter, increasing its weight and affecting its refractive power, thus impacting image quality. Therefore, by controlling f4 / EP34 within this reasonable range, this application can optimize the shape of the fourth lens, improve its assembly stability, and thereby improve the overall assembly process of the optical system, while also enhancing the overall quality of the optical system. Attached Figure Description

[0026] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an undue limitation of the present invention. In the drawings:

[0027] Figure 1 A dimensioned diagram of an optical system according to an alternative embodiment of the present invention is shown;

[0028] Figure 2 A schematic diagram of the optical system of Embodiment 1-1 of this utility model is shown;

[0029] Figure 3 A schematic diagram of the optical system of Embodiments 1-2 of this utility model is shown;

[0030] Figures 4 to 7 The on-axis chromatic aberration curve, astigmatism curve, distortion curve, and magnification chromatic aberration curve of the optical system of Embodiment 1 of this utility model are shown respectively.

[0031] Figure 8 A schematic diagram of the optical system of Embodiment 2-1 of this utility model is shown;

[0032] Figure 9 A schematic diagram of the optical system of Embodiment 2-2 of this utility model is shown;

[0033] Figures 10 to 13 The on-axis chromatic aberration curve, astigmatism curve, distortion curve, and magnification chromatic aberration curve of the optical system of Embodiment 2 of this utility model are shown respectively.

[0034] Figure 14 A schematic diagram of the optical system of Embodiment 3-1 of this utility model is shown;

[0035] Figure 15 A schematic diagram of the optical system of Embodiment 3-2 of this utility model is shown;

[0036] Figures 16 to 19 The on-axis chromatic aberration curve, astigmatism curve, distortion curve, and magnification chromatic aberration curve of the optical system of Embodiment 3 of this utility model are shown respectively.

[0037] Figure 20 A schematic diagram of the optical system of Embodiment 4-1 of this utility model is shown;

[0038] Figure 21 A schematic diagram of the optical system of Embodiment 4-2 of this utility model is shown;

[0039] Figures 22 to 25 The on-axis chromatic aberration curve, astigmatism curve, distortion curve, and magnification chromatic aberration curve of the optical system of Embodiment 4 of this utility model are shown respectively.

[0040] The above figures 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 Implementation

[0042] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0043] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0044] In this utility model, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used in relation to the direction shown in the accompanying drawings, or in relation to the vertical, perpendicular, or gravitational direction of the component itself; similarly, for ease of understanding and description, "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not used to limit this utility model.

[0045] It should be noted that in this specification, the terms "first," "second," "third," etc., are used only to distinguish one feature from another and do not imply any limitation on the features. Therefore, without departing from the teachings of this application, the first lens discussed below may also be referred to as the second lens or the third lens.

[0046] In the accompanying drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustrative purposes only and are not drawn strictly to scale.

[0047] In this paper, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of the convexity is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the location of the concaveness is not defined, it means that the lens surface is concave at least in the paraxial region. The surface shape in the paraxial region can be determined according to the judgment method commonly known in the art, using the R value (R refers to the radius of curvature of the paraxial region, usually the R value in the lens database of optical software) to determine concavity or convexity. For the object side, when the R value is positive, it is determined to be convex, and when the R value is negative, it is determined to be concave; for the image side, when the R value is positive, it is determined to be concave, and when the R value is negative, it is determined to be convex. In this application, the left side is the object side, and the right side is the image side.

[0048] To address the problem of poor assembly stability caused by the five-element optical system in the prior art in meeting the requirements of image size control, this utility model provides an optical system.

[0049] like Figures 1 to 25As shown, in an optional embodiment of this application, the optical system includes a lens barrel and a lens group and at least one spacer disposed in the lens barrel. The lens group consists of five lenses, which are arranged sequentially from the object side to the image side along the optical axis as a first lens, a second lens, a third lens, a fourth lens, and a fifth lens. The at least one spacer includes a second spacer located between the second and third lenses and in contact with the image-side surface of the second lens, a third spacer located between the third and fourth lenses and in contact with the image-side surface of the third lens, and a fourth spacer located between the fourth and fifth lenses and in contact with the image-side surface of the fourth lens. The effective focal length f3 of the third lens, the axial spacing EP23 between the second and third spacers, and the center thickness CT3 of the third lens on the optical axis satisfy the following: -3.23 ≤ f3 / (EP23+CT3) ≤ -3.05. The effective focal length f4 of the fourth lens and the axial spacing EP34 between the third and fourth spacers satisfy the following: -17.45 ≤ f4 / EP34 ≤ -13.71.

[0050] The optical system of this application consists of a lens barrel, five lenses disposed within the lens barrel, and at least one spacer. By rationally arranging the positions of the five lenses and the second to fourth spacers, and ensuring that the optical system satisfies -3.23 ≤ f3 / (EP23+CT3) ≤ -3.05, the overall shape of the third lens can be improved while controlling the image size, thus enhancing the assembly stability of the third lens. However, this leads to assembly problems with the fourth lens. Therefore, this application constrains the fourth lens to -17.45 ≤ f4 / EP34 ≤ -13.71. When this ratio is less than the lower limit, the fourth lens becomes thinner and more curved, making it prone to breakage during assembly; when this ratio is greater than the upper limit, the fourth lens becomes thicker and flatter, increasing its weight and affecting its refractive power, thus impacting image quality. Therefore, by controlling f4 / EP34 within this reasonable range, this application can optimize the shape of the fourth lens, improve its assembly stability, and thereby improve the overall assembly process of the optical system, while also enhancing the overall quality of the optical system.

[0051] Furthermore, refer to Table 1 below. Table 1 shows the surface shape change of the fourth lens in the optical systems of Examples 1, 2, and 3 under the same applied load. The upper and lower rows of data corresponding to the displacement in Table 1 are the displacement data of the object-side and image-side surfaces 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 deforms. 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] As shown in Table 1, 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 minimized, the surface shape change is minimized, and the structural sensitivity, stability, and assembly stability are good. When f3 / (EP23+CT3) = -2.89 and f4 / EP34 = -21.36 are satisfied, the surface shape change of the fourth lens is larger, the structural sensitivity is poorer, and the assembly stability is poorer. When f3 / (EP23+CT3) = -5.4 and f4 / EP34 = -11.52 are satisfied, the shape of the fourth lens is thinner and more curved, making it prone to breakage during assembly, and the surface shape change of the fourth lens is larger, resulting in poorer structural sensitivity and assembly stability. Therefore, 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 fourth lens is thicker and flatter, increasing its weight and affecting its refractive power. However, the deformation of the two surfaces of the fourth lens is minimal, resulting in optimal structural sensitivity and stability. Therefore, by constraining -3.23≤f3 / (EP23+CT3)≤-3.05 and -17.45≤f4 / EP34≤-13.71, this application can improve the overall shape of the third lens and enhance its assembly stability while controlling the image size. Simultaneously, it can optimize the shape of the fourth lens, improving its assembly stability, thereby improving the overall assembly process of the optical system and enhancing its overall quality.

[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 housed in the first lens barrel, and the second, third, fourth, and fifth lenses are all housed in the second lens barrel. Specifically, the second, third, and fourth spacers are all housed in the second lens barrel.

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

[0057] In this embodiment, the radius of curvature R2 of the image-side surface of the first lens, the outer diameter D10m of the image-side end face of the first lens barrel, and the inner diameter d10m of the image-side end face 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 face 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 radius of curvature R3 of the object-side surface of the second lens, the refractive index N2 of the second lens, and the outer diameter D20s of the object-side end face of the second lens barrel satisfy the following condition: 1.09 ≤ R3 × N2 / D20s ≤ 1.40. By controlling this condition, 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, and the overall quality can be improved while ensuring 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 radius of curvature R4 of the image-side surface of the second lens satisfy the following condition: -11.96 ≤ R4 / (D2s-d2s) ≤ -3.95. By controlling this condition, 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, enhancing the overall strength of the second lens, and reducing the risk of internal stray light.

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

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

[0062] In this embodiment, the outer diameter D20s of the object-side end face of the second lens barrel, the inner diameter d20s of the object-side end face of the second lens barrel, the outer diameter D2s of the object-side side face of the second spacer, and the inner diameter d2s of the object-side side face of the second spacer satisfy the following ratio: 1.08 ≤ (D20s - d20s) / (D2s - d2s) ≤ 2.65. By controlling the ratio of the difference between the outer and inner diameters of the object-side end face of the second lens barrel to the difference between the outer and inner diameters of the object-side side face 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, assembly steps can be reduced, and the overall quality can be enhanced.

[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 the following relationship: -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 curvature of the third lens can be improved while simultaneously improving its refractive power, thereby improving the shape of the third lens, improving its dispersion, and enhancing image quality. By controlling the ratio of this product to the sum of the outer diameters of the image-side surface of the second spacer and the object-side surface of the third spacer, the outer diameter of the third lens can be limited, thereby improving the shape of the third lens, enhancing assembly stability, and improving image quality.

[0064] In this embodiment, the inner diameter d3s of the object side of the third spacer, the inner diameter d3m of the image side of the third spacer, and the radius of curvature R6 of the image side of the third lens satisfy the following relationship: 1.59 ≤ (d3s + d3m) / R6 ≤ 1.97. The radius of curvature of the image side of the third lens reflects the degree of curvature of the third lens, and the sum of the inner diameters of the object side and the image side of the third spacer reflects the length of the lens. By controlling the ratio of these 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 radius of curvature 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 the following relationship: -2.31 ≤ D3m / R7 ≤ -1.81. The radius of curvature reflects the degree of bending 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 these two can improve the thickness ratio of the fourth lens, making the shaping of the fourth lens more reasonable and improving 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 radius of curvature R8 of the image-side surface of the fourth lens satisfy the following relationship: -10.99≤R8 / (D4s-d4s)≤3.54. The radius of curvature of the image-side surface 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 surface of the fourth spacer reflects the size of the edge structure portion of the fourth lens. This balances the size ratio between the edge structure portion and the central optical effective portion of the fourth lens, improves the assembly stability of the fourth lens, and ensures the reliability of the fourth lens.

[0067] It should be noted that the first to fifth lenses described above are all composed of a central optical effective part and an edge structure part. The edge structure part is located on the outer periphery of the central optical effective part and is arranged circumferentially around the central optical effective part. The central optical effective part is used for the passage of imaging light, while the edge structure part is not used for the passage of imaging light, but is used to abut against the lens barrel, adjacent lenses, or adjacent spacers.

[0068] In this embodiment, the central thickness CT5 of the fifth lens on the optical axis, the air gap T45 between the fourth and fifth lenses on the optical axis, and the maximum axial thickness CP4 of the fourth spacer satisfy the following condition: 0.86 ≤ (CT5 + T45) / CP4 ≤ 1.86. By controlling the central thickness of the fifth lens and the sum of the air gaps between the fourth and fifth lenses on the optical axis, the relative positions of the fourth and fifth lenses, as well as 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 positional relationship between the fourth and fifth lenses can be improved, thereby improving assembly stability.

[0069] In this embodiment, the effective focal length f3 of the third lens and the axial distance EP23 between the second and third spacers satisfy the following condition: -5.24 ≤ f3 / EP23 ≤ -4.95. By reasonably controlling the ratio of the effective focal length of the third lens to the axial distance between the second and third spacers 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 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. By reasonably constraining the optical power and surface shape of each lens, it is beneficial to constrain the trajectory of the imaging light rays to transmit according to the design, ensuring that the light rays can transition smoothly, which is beneficial to correcting aberrations and ensuring image quality.

[0071] Optionally, the optical system in the embodiments of this application can be simulated using software and / or tools such as ZEMAX and CODEV. During the simulation process using such software and / or tools, the surface profile of each lens can be appropriately adjusted according to the surface profile simulation provided by the software and / or tools used.

[0072] like Figures 1 to 25 As shown, in another optional embodiment of this application, an optical system is also provided. The optical system includes a lens barrel and a lens group disposed in the lens barrel and at least one spacer. The lens group consists of five lenses, which are arranged sequentially along the optical axis from the object side to the image side as a first lens with positive optical power, a second lens with positive optical power, a third lens with negative optical power, a fourth lens with negative optical power, and a fifth lens with positive optical power. The at least one spacer includes a second spacer located between the second and third lenses and in contact with the image side of the second lens, and a spacer located between the third and fourth lenses and in contact with the image side of the third lens. The third spacer is in contact with the side portion, and the fourth spacer is located between the fourth and fifth lenses 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 and third spacers 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 of the fourth spacer, the inner diameter d4s of the object side of the fourth spacer and the radius of curvature R8 of the image side of the fourth lens satisfy: -10.99≤R8 / (D4s-d4s)≤3.54.

[0073] The optical system of this application consists of a lens barrel, five lenses disposed within the lens barrel, and at least one spacer. By rationally arranging the positions of the five lenses and the second to fourth spacers, and ensuring that the optical system satisfies -3.23≤f3 / (EP23+CT3)≤-3.05, the overall shape of the third lens can be improved while controlling the image size, thus enhancing the assembly stability of the third lens. However, this situation leads to assembly problems with the fourth lens. Therefore, this application constrains the fourth lens by setting -10.99≤R8 / (D4s-d4s)≤3.54. The radius of curvature of the image-side surface of the fourth lens reflects the degree of curvature of the fourth lens, and the difference between the outer and inner diameters of the object-side surface of the fourth spacer reflects the size of the edge structure of the fourth lens. This balances the size ratio between the edge structure and the central optical effective part of the fourth lens, improving the assembly stability of the fourth lens and ensuring its reliability.

[0074] Of course, this embodiment may also include other parametric expressions as described in the above embodiments, which will not be elaborated here.

[0075] like Figures 1 to 25 As shown, in another optional embodiment of this application, an optical system is also provided, including a lens barrel and a lens group and at least one spacer disposed in the lens barrel. The lens group consists of five lenses, which are arranged sequentially from the object side to the image side along the optical axis as a first lens with positive optical power, a second lens with positive optical power, a third lens with negative optical power, a fourth lens with negative optical power, and a fifth lens with positive optical power. The at least one spacer includes a third spacer located between the third lens and the fourth lens and in contact with the image-side surface 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 of the fourth lens. The effective focal length f3 of the third lens and the outer diameter D3s of the object side surface 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.

[0076] The optical system of this application consists of a lens barrel, five lenses disposed within the lens barrel, and at least one spacer. By rationally 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 shape of the third and fourth lenses, ensure forming stability, effectively avoid assembly problems caused by unreasonable lens sizes, and at the same time, it is beneficial for the third and fourth spacers to effectively intercept stray light from the edges, ensuring image quality.

[0077] Of course, this embodiment may also include other parametric expressions as described in the above embodiments, which will not be elaborated here.

[0078] The optical system in this application may employ multiple lenses, such as the five lenses described above. In this application, at least one of the mirror surfaces of each lens is an aspherical mirror surface. An aspherical lens is characterized by a continuously changing curvature from its center to its periphery. Unlike a spherical lens, which has a constant curvature from its center to its periphery, an aspherical lens has superior curvature radius characteristics, offering advantages in improving distortion and astigmatism. By using aspherical lenses, aberrations occurring during imaging can be eliminated as much as possible, thereby improving image quality.

[0079] However, those skilled in the art will understand that the number of lenses constituting the optical system can be varied to obtain the various results and advantages described herein without departing from the technical solutions claimed in this application. For example, although five lenses have been described as an example in the embodiments, 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 showing the dimensions of an optical system according to this application is provided. Figure 1 The parameters D10s, d10m, D10m, D20s, d20s, D4s, d4s, d2s, D2s, D2m, D3s, CP4, EP202, EP23, EP34, d3s, d3m, and D3m are clearly and intuitively illustrated to provide a clear understanding of their meaning. To facilitate the description of the optical system and the specific lens profiles, these parameters will not be shown in the accompanying drawings when describing specific embodiments.

[0081] The following description, with reference to the accompanying drawings, further illustrates examples of specific surface shapes and parameters of the optical system applicable to the above embodiments.

[0082] It should be noted that in the following Embodiment 1, there are two examples: Embodiment 1-1 and Embodiment 1-2; in Embodiment 2, there are two examples: Embodiment 2-1 and Embodiment 2-2; in Embodiment 3, there are two examples: Embodiment 3-1 and Embodiment 3-2; and in Embodiment 4, there are two examples: Embodiment 4-1 and Embodiment 4-2. In the two examples within the same embodiment, the parameters such as the radius of curvature, center thickness, and spacing between lenses, as well as the higher-order coefficients, of the optical system are the same. However, 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 used for imaging is the same, but the auxiliary structures used for imaging are different.

[0083] It should be noted that any one of the examples in Embodiments 1 to 4 described below is applicable to all embodiments of this application.

[0084] Example 1

[0085] like Figures 2 to 7 As shown, the optical system of Embodiment 1 is described. Figure 2 A schematic diagram of the optical system of Embodiment 1-1 is shown. Figure 3 A schematic diagram of the optical system of Embodiments 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, with the second lens barrel P20 located on the image side of the first lens barrel P10. A first lens E1 is disposed in the first lens barrel P10. From the object side to the image side, the second lens barrel P20 contains, in sequence, 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.

[0087] like Figure 2 The diagram shows a schematic of the optical system in Embodiment 1-1. In this example, a fourth auxiliary spacer element is also provided on the image side of the fourth spacer P4. The object side and image side of the second spacer P2 abut against the image side S5 of the second lens and the object side S6 of the third lens, respectively. The object side and image side of the third spacer P3 abut against the image side S7 of the third lens and the object side S8 of the fourth lens, respectively. The object side and image side of the fourth spacer P4 abut against the image side S9 of the fourth lens and the object side of the fourth auxiliary spacer element, respectively. The image side of the fourth auxiliary spacer element abuts against the object side S11 of the fifth lens.

[0088] like Figure 3 The diagram shown is a structural schematic of the optical system of Embodiment 1-2. In this example, the bearing and contact method of each spacer is the same as that of Embodiment 1-1, and can be referred to the relevant description in Embodiment 1-1, which will not be repeated here.

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

[0090] Table 2

[0091] Parameters / Examples 1-1 1-2 d10m (mm) 8.095 8.095 D10s(mm) 8.283 8.448 D10m (mm) 8.244 8.408 d20s(mm) 4.676 4.676 D20s(mm) 5.989 5.989 d2s(mm) 4.268 4.268 D2s(mm) 5.042 5.042 D2m(mm) 5.042 5.042 D3s(mm) 5.142 5.142 d4s(mm) 4.229 4.229 D4s(mm) 4.661 4.822 EP202(mm) 0.828 0.828 EP23(mm) 1.330 1.328 EP34(mm) 0.923 0.921 CP4 (mm) 0.870 0.870 d3s(mm) 4.072 4.072 d3m(mm) 4.072 4.072 D3m(mm) 5.142 5.142

[0092] In Embodiment 1, 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.

[0093] In Embodiment 1, 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.

[0094] Table 3 shows the basic structural parameters of the optical system in Embodiment 1, where the units for radius of curvature and thickness / distance are millimeters (mm). In the table below, S3 and S10 represent the positions of physical apertures, indicating physical light blocking, such as lens barrels or spacers.

[0095] Table 3

[0096]

[0097]

[0098] In Embodiment 1, the object-side surface and image-side surface of the first lens E1 to the fifth lens E5 are both aspherical surfaces. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formula:

[0099]

[0100] Where x is the distance vector from the vertex of the aspherical surface at a height h along the optical axis; c is the paraxial curvature of the aspherical surface, c = 1 / R, i.e., the paraxial curvature c is the reciprocal of the radius of curvature R in Table 1 above; k is the conic coefficient; Ai is the i-th order correction coefficient of the aspherical surface. Table 4 below gives the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 that can be used for each aspherical mirror S1-S12 in Example 1.

[0101] Table 4

[0102] 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

[0103] Figure 4 The on-axis chromatic aberration curve of the optical system of Embodiment 1 is shown, which represents the deflection of the focal point of light of different wavelengths after passing through the optical system. Figure 5 The astigmatism curves of the optical system of Embodiment 1 are shown, which represent the meridional image plane curvature and the sagittal image plane curvature. Figure 6 The distortion curves of the optical system in Embodiment 1 are shown, representing the distortion magnitude values ​​corresponding to different field of view angles. Figure 7 The magnification chromatic aberration curve of the optical system of Embodiment 1 is shown, which represents the deviation of light at different image heights on the imaging plane after passing through the optical system.

[0104] according to Figures 4 to 7 As can be seen, the optical system given in Example 1 can achieve good imaging quality.

[0105] Example 2

[0106] like Figures 8 to 13 As shown, the optical system of Embodiment 2 is described. Figure 8 A schematic diagram of the optical system of Embodiment 2-1 is shown. Figure 9 A schematic diagram of the optical system of Embodiment 2-2 is shown.

[0107] like Figure 8 and Figure 9 As shown, the optical system includes a first lens barrel P10 and a second lens barrel P20, with the second lens barrel P20 located on the image side of the first lens barrel P10. A first lens E1 is disposed in the first lens barrel P10. From the object side to the image side, the second lens barrel P20 contains, in sequence, 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.

[0108] like Figure 8 The diagram shows a schematic of the optical system in Embodiment 2-1. In this example, a fourth auxiliary spacer element is also provided on the image side of the fourth spacer P4. The object side and image side of the second spacer P2 abut against the image side S5 of the second lens and the object side S6 of the third lens, respectively. The object side and image side of the third spacer P3 abut against the image side S7 of the third lens and the object side S8 of the fourth lens, respectively. The object side and image side of the fourth spacer P4 abut against the image side S9 of the fourth lens and the object side of the fourth auxiliary spacer element, respectively. The image side of the fourth auxiliary spacer element abuts against the object side S11 of the fifth lens.

[0109] like Figure 9 The diagram shown is a structural schematic of the optical system in Embodiment 2-2. In this example, the bearing and contact method of each spacer is the same as in Embodiment 2-1, and can be referred to the relevant description in Embodiment 2-1, which will not be repeated here.

[0110] In summary, the structural parameters of the optical system in Embodiment 2 under Embodiments 2-1 and 2-2 are shown in Table 5. (Unit: mm)

[0111] Table 5

[0112] 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

[0113] In Embodiment 2, 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.

[0114] In Example 2, 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.

[0115] Table 6 shows the basic structural parameters of the optical system in Embodiment 2, where the units for radius of curvature and thickness / distance are millimeters (mm). In the table below, S3 and S10 represent the positions of physical apertures, indicating physical light blocking, such as lens barrels or spacers.

[0116] Table 6

[0117]

[0118] Table 7 below shows the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 that can be used for each aspherical mirror S1-S12 in Example 2.

[0119] Table 7

[0120]

[0121]

[0122] Figure 10 The on-axis chromatic aberration curve of the optical system of Embodiment 2 is shown, which represents the deviation of the focal point of light of different wavelengths after passing through the optical system. Figure 11 The astigmatism curves of the optical system of Embodiment 2 are shown, which represent the meridional image plane curvature and the sagittal image plane curvature. Figure 12 The distortion curves of the optical system in Embodiment 2 are shown, representing the distortion magnitude values ​​corresponding to different field of view angles. Figure 13 The magnification chromatic aberration curve of the optical system of Embodiment 2 is shown, which represents the deviation of light at different image heights on the imaging plane after passing through the optical system.

[0123] according to Figures 10 to 13 It can be seen that the optical system given in Example 2 can achieve good imaging quality.

[0124] Example 3

[0125] like Figures 14 to 19 As shown, the optical system of Embodiment 3 is described. Figure 14 A schematic diagram of the optical system of Embodiment 3-1 is shown. Figure 15 A schematic diagram of the optical system of Embodiment 3-2 is shown.

[0126] like Figure 14 and Figure 15As shown, the optical system includes a first lens barrel P10 and a second lens barrel P20, with the second lens barrel P20 located on the image side of the first lens barrel P10. A first lens E1 is disposed in the first lens barrel P10. From the object side to the image side, the second lens barrel P20 contains, in sequence, 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.

[0127] like Figure 14 The diagram shows a schematic of the optical system in Embodiment 3-1. In this example, a fourth auxiliary spacer element is also provided on the image side of the fourth spacer P4. The object side and image side of the second spacer P2 abut against the image side S5 of the second lens and the object side S6 of the third lens, respectively. The object side and image side of the third spacer P3 abut against the image side S7 of the third lens and the object side S8 of the fourth lens, respectively. The object side and image side of the fourth spacer P4 abut against the image side S9 of the fourth lens and the object side of the fourth auxiliary spacer element, respectively. The image side of the fourth auxiliary spacer element abuts against the object side S11 of the fifth lens.

[0128] like Figure 15 The diagram shown is a structural schematic of the optical system of Embodiment 3-2. In this example, the bearing and contact method of each spacer is the same as that of Embodiment 3-1, and can be referred to the relevant description in Embodiment 3-1, which will not be repeated here.

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

[0130] Table 8

[0131]

[0132]

[0133] In Embodiment 3, 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 Embodiment 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 in Embodiment 3, where the units for radius of curvature and thickness / distance are millimeters (mm). In the table below, S3 and S10 represent the positions of physical apertures, indicating physical light blocking, such as lens barrels or spacers.

[0136] Table 9

[0137]

[0138] Table 10 below gives the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 that can be used for each aspherical mirror 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] Figure 16 The on-axis chromatic aberration curve of the optical system of Embodiment 3 is shown, which represents the deviation of the focal point of light of different wavelengths after passing through the optical system. Figure 17 The astigmatism curves of the optical system of Embodiment 3 are shown, which represent the meridional image plane curvature and the sagittal image plane curvature. Figure 18 The distortion curves of the optical system in Embodiment 3 are shown, representing the distortion magnitude values ​​corresponding to different field of view angles. Figure 19 The magnification chromatic aberration curve of the optical system of Embodiment 3 is shown, which represents the deviation of light at different image heights on the imaging plane after passing through the optical system.

[0142] according to Figures 16 to 19 As can be seen, the optical system given in Example 3 can achieve good imaging quality.

[0143] Example 4

[0144] like Figures 20 to 25 As shown, the optical system of Embodiment 4 is described. Figure 20 A schematic diagram of the optical system of Embodiment 4-1 is shown. Figure 21 A schematic diagram of the optical system of Embodiment 4-2 is shown.

[0145] like Figure 20 and Figure 21 As shown, the optical system includes a first lens barrel P10 and a second lens barrel P20, with the second lens barrel P20 located on the image side of the first lens barrel P10. A first lens E1 is disposed in the first lens barrel P10. From the object side to the image side, the second lens barrel P20 contains, in sequence, 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.

[0146] like Figure 20 The diagram shows a schematic of the optical system in Embodiment 4-1. In this example, a fourth auxiliary spacer element is also provided on the image side of the fourth spacer P4. The object side and image side of the second spacer P2 abut against the image side S5 of the second lens and the object side S6 of the third lens, respectively. The object side and image side of the third spacer P3 abut against the image side S7 of the third lens and the object side S8 of the fourth lens, respectively. The object side and image side of the fourth spacer P4 abut against the image side S9 of the fourth lens and the object side of the fourth auxiliary spacer element, respectively. The image side of the fourth auxiliary spacer element abuts against the object side S11 of the fifth lens.

[0147] like Figure 21 The diagram shown is a structural schematic of the optical system in Example 4-2. In this example, the abutment and contact method of each spacer is the same as in Example 4-1, and can be referred to the relevant description in Example 4-1, which will not be repeated here.

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

[0149] Table 11

[0150] Parameters / Examples 4-1 4-2 d10m (mm) 8.253 8.253 D10s(mm) 8.259 8.649 D10m (mm) 8.609 8.609 d20s(mm) 4.520 4.520 D20s(mm) 6.296 6.904 d2s(mm) 4.238 4.238 D2s(mm) 5.417 5.137 D2m(mm) 5.417 5.137 D3s(mm) 5.517 6.100 d4s(mm) 4.260 4.138 D4s(mm) 5.145 5.548 EP202(mm) 0.815 0.815 EP23(mm) 1.343 1.345 EP34(mm) 0.916 0.918 CP4 (mm) 1.032 1.304 d3s(mm) 4.035 4.035 d3m(mm) 4.035 4.035 D3m(mm) 5.517 6.100

[0151] In Embodiment 4, 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 Example 4, 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 in Embodiment 4, where the units for radius of curvature and thickness / distance are millimeters (mm). In the table below, S3 and S10 represent the positions of physical apertures, indicating physical light blocking, such as lens barrels or spacers.

[0154] Table 12

[0155]

[0156]

[0157] Table 13 below gives the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, and A20 that can be used for each aspherical mirror 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] Figure 22 The on-axis chromatic aberration curve of the optical system of Embodiment 4 is shown, which represents the deviation of the focal point of light of different wavelengths after passing through the optical system. Figure 23 The astigmatism curves of the optical system of Embodiment 4 are shown, which represent the meridional image plane curvature and the sagittal image plane curvature. Figure 24 The distortion curves of the optical system in Embodiment 4 are shown, representing the distortion magnitude values ​​corresponding to different field of view angles. Figure 25 The magnification chromatic aberration curve of the optical system of Embodiment 4 is shown, which represents the deviation of light at different image heights on the imaging plane after passing through the optical system.

[0161] according to Figures 22 to 25 As can be seen, the optical system given in Example 4 can achieve good imaging quality.

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

[0163] Table 14

[0164]

[0165]

[0166] Table 15 shows the effective focal lengths of each lens in the optical systems of Embodiments 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] This application also provides an imaging device, whose electronic photosensitive element can be a photocoupled device (CCD) or a complementary metal oxide semiconductor device (CMOS). The imaging device can be a stand-alone imaging device such as a digital camera, or an imaging module integrated into a mobile electronic device such as a mobile phone. The imaging device is equipped with the optical system described above.

[0170] Obviously, the embodiments described above are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this utility model.

[0171] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0172] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0173] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. An optical system, characterized in that, It includes a lens barrel, a lens assembly disposed within the lens barrel, and at least one spacer. The lens group consists of five lenses, which are arranged sequentially from the object side to the image side along the optical axis as the first lens, the second lens, the third lens, the fourth lens, and the fifth lens; 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 the following: -3.23≤f3 / (EP23+CT3)≤-3.05; The effective focal length f4 of the fourth lens and the axial distance EP34 between the third spacer and the fourth spacer satisfy: -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 being located on the image side of the first lens barrel, the first lens being housed in the first lens barrel, and the second lens, the third lens, the fourth lens and the fifth lens being housed 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 face of the first lens barrel, the radius of curvature R1 of the object-side surface of the first lens, and the center thickness CT1 of the first lens on the optical axis satisfy the following condition: 2.10≤D10s / (R1×CT1)≤2.

26.

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

90.

5. The optical system according to claim 2, characterized in that, The radius of curvature R3 of the object side surface of the second lens, the refractive index N2 of the second lens, and the outer diameter D20s of the object side end face of the second lens barrel satisfy the following condition: 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 radius of curvature R4 of the image-side surface of the second lens satisfy the following relationship: -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 face of the second lens barrel and the second spacer satisfy the following condition: 7.05≤f2 / EP202≤7.

78.

8. The optical system according to claim 1, characterized in that, The air gap T34 between the third lens and the fourth lens on the optical axis and the air gap T45 between the fourth lens and the fifth lens on the optical axis satisfy the following condition: 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 face of the second lens tube, the inner diameter d20s of the object-side end face of the second lens tube, the outer diameter D2s of the object-side side face of the second spacer, and the inner diameter d2s of the object-side side face of the second spacer satisfy the following: 1.08≤(D20s-d20s) / (D2s-d2s)≤2.

65.

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

84.

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

97.

12. The optical system according to claim 1, characterized in that, The radius of curvature R7 of the object side of the fourth lens and the outer diameter D3m of the image side of the third spacer satisfy the following condition: -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 radius of curvature R8 of the image side surface of the fourth lens satisfy the following relationship: -10.99≤R8 / (D4s-d4s)≤3.

54.

14. The optical system according to claim 1, characterized in that, The central thickness CT5 of the fifth lens on the optical axis, the air gap T45 between the fourth and fifth lenses on the optical axis, and the maximum axial thickness CP4 of the fourth spacer satisfy the following condition: 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 distance EP23 between the second spacer and the third spacer satisfy the following condition: -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 first lens has a convex object-side surface and a concave image-side surface; the second lens has a convex object-side surface and a convex image-side surface; the third lens has a concave object-side surface and a concave image-side surface; the fourth lens has a concave object-side surface and a convex image-side surface; and the fifth lens has a convex object-side surface and a concave image-side surface.

Images