Optical system

Abstract

The application provides an optical system, comprising: a lens group, the lens group sequentially comprises a first lens to a fifth lens from an object side of the optical system to an image side of the optical system; a plurality of spacers, among the plurality of spacers, a third spacer is located between the third lens and the fourth lens and at least partially contacts an image side surface of the third lens, and a fourth spacer is located between the fourth lens and the fifth lens and at least partially contacts an image side surface of the fourth lens; a lens barrel, the lens barrel has a receiving space, the lens group and the plurality of spacers are accommodated in the receiving space; an air interval T34 of the third lens and the fourth lens on an optical axis, an air interval T45 of the fourth lens and the fifth lens on the optical axis satisfy: 4.9 <= T45 / T34 <= 6.99; a central thickness CT4 of the fourth lens on the optical axis, and a spacing distance EP34 of the third spacer and the fourth spacer along the direction of the optical axis satisfy: 1.47 <= CT4 / EP34 <= 2.03. The application solves the problem of the divergence of the defocus curve of the optical system in the prior art.

Description

Technical Field

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

[0002] Driven by technology, optics has permeated every aspect of life, with optical systems responsible for image capture playing a crucial role in fields such as security, automotive, drones, and consumer electronics. To correct off-axis aberrations, the shape and arrangement of the rear-end lenses in traditional five-element optical systems are limited. However, this results in excessively large refraction angles of the edge rays at the rear of the optical system, affecting the smoothness of the defocus curve and causing it to become unfocused, thus impacting the imaging performance of the optical system. Furthermore, the lenses designed to these limits have poor manufacturability, hindering the widespread application of five-element optical systems. Therefore, adjusting the shape and position of the rear-end lenses and spacers to improve defocus curve performance is a pressing issue that needs to be addressed. Summary of the Invention

[0003] The main objective of this invention is to provide an optical system that solves the problem of defocus curve divergence in existing optical systems.

[0004] To achieve the above objectives, according to one aspect of the present invention, an optical system is provided, comprising: a lens group having five lenses having optical power, the lens group including a first lens to a fifth lens sequentially from the object side to the image side of the optical system; a plurality of spacers, wherein a third spacer is located between a third lens and a fourth lens and at least partially contacts the image side of the third lens, and a fourth spacer is located between a fourth lens and a fifth lens and at least partially contacts the image side of the fourth lens; a lens barrel having a receiving space, the lens group and the plurality of spacers being housed within the receiving space; wherein the air gap T34 between the third and fourth lenses on the optical axis of the optical system and the air gap T45 between the fourth and fifth lenses on the optical axis satisfy: 4.9 ≤ T45 / T34 ≤ 6.99; the center thickness CT4 of the fourth lens on the optical axis and the spacing EP34 between the third and fourth spacers along the optical axis satisfy: 1.47 ≤ CT4 / EP34 ≤ 2.03.

[0005] According to another aspect of the present invention, an optical system is provided, comprising: a lens group having five lenses having optical power, the lens group including a first lens to a fifth lens sequentially from the object side to the image side of the optical system; a plurality of spacers, wherein a third spacer is located between a third lens and a fourth lens and at least partially contacts the image side of the third lens, and a fourth spacer is located between a fourth lens and a fifth lens and at least partially contacts the image side of the fourth lens; a lens barrel having a receiving space, the lens group and the plurality of spacers being housed within the receiving space; wherein the air gap T34 between the third and fourth lenses on the optical axis of the optical system and the air gap T45 between the fourth and fifth lenses on the optical axis satisfy: 4.9 ≤ T45 / T34 ≤ 6.99; and the outer 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: -2.83 ≤ D4s / R8 ≤ -2.39.

[0006] Furthermore, among the multiple spacers, the one located between the first lens and the second lens and in at least partial contact with the image side of the first lens is the first spacer. The radius of curvature R1 of the object side of the first lens, the inner diameter d0s of the object side end face of the lens barrel, and the inner diameter d1s of the object side of the first spacer satisfy the following: 2.83≤R1 / (d0s-d1s)≤3.78.

[0007] Furthermore, among the multiple spacers, the spacer located between the first lens and the second lens and in at least partial contact with the image side of the first lens is the first spacer. The effective focal length f1 of the first lens, the distance EP01 between the object side end face of the lens barrel and the object side face of the first spacer along the optical axis, and the center thickness CT1 of the first lens on the optical axis satisfy the following: -4.87≤f1 / (EP01+CT1)≤-2.93.

[0008] Furthermore, among the multiple spacers, the one located between the first lens and the second lens and in at least partial contact with the image side of the first lens is the first spacer. The radius of curvature R2 of the image side of the first lens, the outer diameter D1s of the object side of the first spacer, and the inner diameter d1s of the object side of the first spacer satisfy the following: 0.67≤R2 / (D1s-d1s)≤1.39.

[0009] Furthermore, among the multiple spacers, the spacer located between the first lens and the second lens and in at least partial contact with the image side of the first lens is the first spacer, and the spacer located between the second lens and the third lens and in at least partial contact with the image side of the second lens is the second spacer. The effective focal length f2 of the second lens, the air gap T12 between the first lens and the second lens on the optical axis, and the spacing EP12 between the first spacer and the second spacer along the optical axis satisfy the following: 1.29≤f2 / (T12+EP12)≤2.83.

[0010] Furthermore, among the multiple spacers, the one located between the second lens and the third lens and in at least partial contact with the image side of the second lens is the second spacer. The radius of curvature R3 of the object side of the second lens, the center thickness CT2 of the second lens on the optical axis, and the inner diameter d2s of the object side of the second spacer satisfy the following: 0.99mm≤R3×CT2 / d2s≤1.72mm.

[0011] Furthermore, among the multiple spacers, the one located between the second lens and the third lens and in at least partial contact with the image side of the second lens is the second spacer. The radius of curvature R4 of the image side of the second lens and the outer diameter D2s of the object side of the second spacer satisfy the following: -2.07≤R4 / D2s≤-0.37.

[0012] Furthermore, among the multiple spacers, the one located between the second lens and the third lens and in at least partial contact with the image side of the second lens is the second spacer. The center thickness CT2 of the second lens on the optical axis, the air gap T23 between the second lens and the third lens on the optical axis, and the maximum thickness CP2 of the second spacer satisfy the following: 6.01≤CT2 / (T23+CP2)≤6.29.

[0013] Furthermore, among the multiple spacers, the one located between the second lens and the third lens and in at least partial contact with the image-side surface of the second lens is the second spacer. The radius of curvature R5 of the object-side surface of the third lens satisfies the following relationship with the outer diameter D2m of the image-side surface of the second spacer and the inner diameter d2m of the image-side surface of the second spacer: 0.77≤R5 / (D2m-d2m)≤3.48.

[0014] Furthermore, among the multiple spacers, the spacer located between the second lens and the third lens and in at least partial contact with the image side of the second lens is the second spacer. The spacing distance EP23 between the second spacer and the third spacer along the optical axis and the center thickness CT3 of the third lens on the optical axis satisfy the following: 1.72≤EP23 / CT3≤2.06.

[0015] Furthermore, the outer diameter D3s of the object side of the third spacer, the inner diameter d3s of the object side of the third spacer, and the radius of curvature R6 of the image side of the third lens satisfy the following condition: 1.09≤(D3s-d3s) / R6≤1.50.

[0016] Furthermore, the outer diameter D3m of the image side of the third spacer and the radius of curvature R7 of the object side of the fourth lens satisfy the following condition: 0.95≤D3m / R7≤2.69.

[0017] Furthermore, the outer 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 condition: -2.83≤D4s / R8≤-2.39.

[0018] Furthermore, the outer diameter D4m of the image side of the fourth spacer, the inner diameter d4m of the image side of the fourth spacer, and the radius of curvature R9 of the object side of the fifth lens satisfy the following: -1.83≤(D4m-d4m) / R9≤-1.41.

[0019] Furthermore, the first lens has negative optical power, its object-side surface is convex, and its image-side surface is concave; the second lens has positive optical power, its object-side surface is convex, and its image-side surface is convex; the third lens has negative optical power, its object-side surface is convex, and its image-side surface is concave; the fourth lens has positive optical power, its object-side surface is convex, and its image-side surface is convex; and the fifth lens has negative optical power, its object-side surface is concave, and its image-side surface is concave.

[0020] According to the technical solution of this invention, the optical system includes a lens group, multiple spacers, and a lens barrel. The lens group has five lenses with optical power, and the lens group includes a first lens to a fifth lens sequentially from the object side to the image side of the optical system. Among the multiple spacers, the spacer located between the third lens and the fourth lens and in at least partial contact with the image side of the third lens is the third spacer, and the spacer located between the fourth lens and the fifth lens and in at least partial contact with the image side of the fourth lens is the fourth spacer. The lens barrel has a receiving space, and the lens group and the multiple spacers are housed in the receiving space. The air gap T34 between the third lens and the fourth lens on the optical axis of the optical system, and the air gap T45 between the fourth lens and the fifth lens on the optical axis satisfy the following: 4.9 ≤ T45 / T34 ≤ 6.99. The center thickness CT4 of the fourth lens on the optical axis and the spacing distance EP34 between the third spacer and the fourth spacer along the optical axis satisfy the following: 1.47 ≤ CT4 / EP34 ≤ 2.03.

[0021] In this application's five-element optical system, to balance the Petzval field curvature of the optical system, the fourth and fifth lenses have relatively large surface curvatures. This results in the air gap between the fourth and fifth lenses on the optical axis being larger than the air gap between the fourth and third lenses on the optical axis, while satisfying 4.9≤T45 / T34≤6.99. This makes the fourth lens more sensitive during assembly. This application indirectly controls the shape and thickness of the effective diameter portion and the mechanism portion of the fourth lens by controlling the ratio of the center thickness of the fourth lens on the optical axis to the spacing distance between the third and fourth spacers. This limits the refraction angle of light passing through the third and fourth lenses, improves the concentration of the defocus curve of the optical system, and also avoids the shape of the fourth lens being at its limit, improving the manufacturability of the fourth lens, reducing assembly sensitivity, and resulting in better defocus transfer function performance of the optical system. Attached Figure Description

[0022] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0023] Figure 1 A schematic diagram showing partial parameters of the optical system of any optional embodiment of the present invention is shown;

[0024] Figure 2 A schematic diagram of the optical system according to Embodiment 1 of the present invention is shown;

[0025] Figure 3 The on-axis chromatic aberration curve of the optical system according to Embodiment 1 of the present invention is shown;

[0026] Figure 4 The astigmatism curve of the optical system of Embodiment 1 of the present invention is shown;

[0027] Figure 5 The magnification chromatic aberration curve of the optical system of Embodiment 1 of the present invention is shown;

[0028] Figure 6 A schematic diagram of the optical system according to Embodiment 2 of the present invention is shown;

[0029] Figure 7 A schematic diagram of the optical system according to Embodiment 3 of the present invention is shown;

[0030] Figure 8 A schematic diagram of the optical system according to Embodiment 4 of the present invention is shown;

[0031] Figure 9 The on-axis chromatic aberration curve of the optical system of Embodiment 4 of the present invention is shown;

[0032] Figure 10The astigmatism curve of the optical system of Embodiment 4 of the present invention is shown;

[0033] Figure 11 The magnification chromatic aberration curve of the optical system of Embodiment 4 of the present invention is shown;

[0034] Figure 12 A schematic diagram of the optical system according to Embodiment 5 of the present invention is shown;

[0035] Figure 13 A schematic diagram of the optical system according to Embodiment Six of the present invention is shown;

[0036] Figure 14 A schematic diagram of the optical system according to Embodiment 7 of the present invention is shown;

[0037] Figure 15 The on-axis chromatic aberration curve of the optical system of Embodiment 7 of the present invention is shown;

[0038] Figure 16 The astigmatism curve of the optical system of Embodiment 7 of the present invention is shown;

[0039] Figure 17 The magnification chromatic aberration curve of the optical system of Embodiment 7 of the present invention is shown;

[0040] Figure 18 A schematic diagram of the optical system of Embodiment 8 of the present invention is shown;

[0041] Figure 19 A schematic diagram of the optical system according to Embodiment 9 of the present invention is shown;

[0042] Figure 20 The defocus transfer function curve of an optical system of an alternative embodiment 1 of the present invention is shown under the conditions of T45 / T34 = 5.4 and CT4 / EP34 = 1.85.

[0043] Figure 21 The defocus transfer function curves of the optical system in Comparative Example 1 are shown under the conditions of T45 / T34 = 5.4 and CT4 / EP34 = 1.22.

[0044] Figure 22 The defocus transfer function curves of the optical system of Comparative Example 2 are shown under the conditions of T45 / T34 = 5.4 and CT4 / EP34 = 2.41.

[0045] The above figures include the following reference numerals:

[0046] P0, Lens tube; E1, First lens; S1, Object-side surface of the first lens; S2, Image-side surface of the first lens; P1, First spacer; E2, Second lens; S3, Object-side surface of the second lens; S4, Image-side surface of the second lens; P2, Second spacer;

[0047] E3, Third lens; S5, Object-side surface of the third lens; S6, Image-side surface of the third lens; P3, Third spacer; E4, Fourth lens; S7, Object-side surface of the fourth lens; S8, Image-side surface of the fourth lens; P4, Fourth spacer; E5, Fifth lens; S9, Object-side surface of the fifth lens; S10, Image-side surface of the fifth lens; P5, Fifth spacer. Detailed Implementation

[0048] 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.

[0049] 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.

[0050] In this invention, 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 intended to limit this invention.

[0051] 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.

[0052] 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.

[0053] In this paper, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of that 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 that concaveness is not defined, it means that the lens surface is concave at least in the paraxial region. The determination of the surface shape in the paraxial region can be based on the judgment method commonly used by those knowledgeable in the field, 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 convexity or concavity. For the object-side surface, when the R value is positive, it is determined to be convex, and when the R value is negative, it is determined to be concave; for the image-side surface, when the R value is positive, it is determined to be concave, and when the R value is negative, it is determined to be convex.

[0054] In this paper, effective light refers to light rays that can be accurately focused onto the imaging surface, either directly or after refraction within the optical system. These rays follow optical laws, such as the laws of refraction and reflection, as they pass through the optical system, ultimately forming a clear image on the imaging surface.

[0055] In this article, ineffective light refers to light rays that do not participate in the imaging process. This includes light rays that enter the optical system but are not focused on the imaging surface, or light rays that are scattered, reflected, or absorbed within the optical system. Ineffective light rays can be caused by physical limitations in the optical system design (such as asymmetrical or imperfect lens shapes), or by factors such as unevenness, dust, scratches, or uneven coatings on the surface of optical elements. Ineffective light rays not only fail to improve image quality but may also lead to undesirable effects such as image blurring, reduced contrast, or the production of light spots and glare.

[0056] In this paper, each lens consists of an integrally formed effective diameter portion and a mechanism portion. The mechanism portion is ring-shaped and connected to the outer peripheral side of the effective diameter portion. The effective diameter portion is used for light to pass through and participate in imaging; while the mechanism portion is not used for light to pass through and does not participate in imaging, but is used to contact adjacent spacers, adjacent lenses, or lens barrels.

[0057] To address the problem of defocus curve divergence in existing optical systems, this invention provides an optical system.

[0058] First Implementation Method

[0059] like Figures 1 to 20As shown, the optical system includes a lens group, multiple spacers, and a lens barrel. The lens group has five lenses with optical power, and the lens group includes a first lens to a fifth lens sequentially from the object side to the image side of the optical system. Among the multiple spacers, the third spacer is located between the third and fourth lenses and is in at least partial contact with the image side of the third lens, and the fourth spacer is located between the fourth and fifth lenses and is in at least partial contact with the image side of the fourth lens. The lens barrel has a housing space, and the lens group and multiple spacers are housed in the housing space. 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: 4.9 ≤ T45 / T34 ≤ 6.99. The center thickness CT4 of the fourth lens on the optical axis and the spacing EP34 between the third and fourth spacers along the optical axis satisfy the following: 1.47 ≤ CT4 / EP34 ≤ 2.03.

[0060] In this application's five-element optical system, to balance the Petzval field curvature of the optical system, the fourth and fifth lenses have relatively large surface curvatures. This results in the air gap between the fourth and fifth lenses on the optical axis being larger than the air gap between the fourth and third lenses on the optical axis, while satisfying 4.9≤T45 / T34≤6.99. This makes the fourth lens more sensitive during assembly. This application indirectly controls the shape and thickness of the effective diameter portion and the mechanism portion of the fourth lens by controlling the ratio of the center thickness of the fourth lens on the optical axis to the spacing distance between the third and fourth spacers. This limits the refraction angle of light passing through the third and fourth lenses, improves the concentration of the defocus curve of the optical system, and also avoids the shape of the fourth lens being at its limit, improving the manufacturability of the fourth lens, reducing assembly sensitivity, and resulting in better defocus transfer function performance of the optical system.

[0061] Table 1 below and Figures 20 to 22 The defocus modulation transfer function curves of the optical systems of Comparative Example 1, Comparative Example 2, and an alternative scheme 1 of this application are given when T45 / T34 = 5.4 and CT4 / EP34 values ​​are different. The image transmission capability of the optical system at different spatial frequencies is described. The X-axis is the defocus position (unit: mm), which indicates the position where the image deviates from the optimal focus (X = 0 mm). The Y-axis represents the defocus modulation transfer function value, so as to intuitively compare the changes in the image quality of the optical system.

[0062] Table 1

[0063] T45 / T34 5.4 5.4 5.4 CT4 / EP34 1.22 1.85 2.41 Optical system determination Unqualified qualified Unqualified

[0064] From Table 1 and Figure 21It can be seen that, under the condition of CT4 / EP34 = 1.22, the optical system of Comparative Example 1 exhibits significant chromatic aberration and severe divergence in its defocus curve, thus the optical system is deemed unqualified. Figure 22 It can be seen that, under the condition of CT4 / EP34 = 2.41, the optical system of Comparative Example 2 is more sensitive to image plane shift, and the defocus curve drops rapidly, thus the optical system is judged to be unqualified. The optical system of this application, as... Figure 20 As shown, under the condition that CT4 / EP34 = 1.85, that is, 1.47 ≤ CT4 / EP34 ≤ 2.03, the defocus curves of each field of view are relatively concentrated, the imaging performance of the optical system is good, and it is judged to be qualified.

[0065] In this embodiment, among the multiple spacers, the spacer located between the first lens and the second lens and in at least partial contact with the image-side surface of the first lens is the first spacer. The radius of curvature R1 of the object-side surface of the first lens, the inner diameter d0s of the object-side end face of the lens barrel, and the inner diameter d1s of the object-side surface of the first spacer satisfy the following: 2.83 ≤ R1 / (d0s-d1s) ≤ 3.78. By limiting R1 / (d0s-d1s) within a reasonable range, the ratio of the radius of curvature of the object-side surface of the first objective lens to the difference between the inner diameter of the object-side end face of the lens barrel and the inner diameter of the object-side surface of the first spacer is controlled. This achieves the purpose of controlling the shape of the chamfer of the inner diameter of the first spacer, which can prevent stray light from being transmitted from the object-side surface of the first lens to the inner diameter surface of the first spacer, thereby improving the imaging quality of the optical system.

[0066] In this embodiment, among the multiple spacers, the spacer located between the first lens and the second lens and in at least partial contact with the image-side surface of the first lens is the first spacer. The effective focal length f1 of the first lens, the distance EP01 between the object-side end face of the lens barrel and the object-side surface of the first spacer along the optical axis, and the center thickness CT1 of the first lens on the optical axis satisfy the following: -4.87≤f1 / (EP01+CT1)≤-2.93. By limiting f1 / (EP01+CT1) within a reasonable range, the ratio of the effective focal length of the first lens to the sum of the distance between the object-side end face of the lens barrel and the first spacer and the center thickness of the first lens is controlled. This achieves the purpose of controlling the focal length and shape of the first lens at the front end of the optical system, making the light reaching the second lens transition smoothly, reducing the incident angle of the light on subsequent elements, and improving the MTF (modulation transfer function) performance.

[0067] In this embodiment, among the multiple spacers, the spacer located between the first lens and the second lens and in at least partial contact with the image-side surface of the first lens is the first spacer. The radius of curvature R2 of the image-side surface of the first lens, the outer diameter D1s of the object-side surface of the first spacer, and the inner diameter d1s of the object-side surface of the first spacer satisfy the following: 0.67≤R2 / (D1s-d1s)≤1.39. By limiting R2 / (D1s-d1s) within a reasonable range, the ratio of the radius of curvature of the image-side surface of the first lens to the difference between the outer and inner diameters of the object-side surface of the first spacer is controlled. This achieves the purpose of controlling the thickness of the bearing wall of the lenses supported by the first spacer, avoiding excessively thin bearing wall thickness of the lenses, reducing the risk of unstable bearing wall thickness due to shrinkage during the molding of the first spacer, and also reducing the risk of unstable assembly of the second lens due to deformation of the first spacer during assembly.

[0068] In this embodiment, among the multiple spacers, the spacer located between the first lens and the second lens and in at least partial contact with the image-side surface of the first lens is the first spacer, and the spacer located between the second lens and the third lens and in at least partial contact with the image-side surface of the second lens is the second spacer. The effective focal length f2 of the second lens, the air gap T12 between the first and second lenses on the optical axis, and the spacing EP12 between the first and second spacers along the optical axis satisfy the following: 1.29 ≤ f2 / (T12+EP12) ≤ 2.83. By limiting f2 / (T12+EP12) within a reasonable range, the ratio of the effective focal length of the second lens to the sum of the air gap between the first and second lenses on the optical axis and the spacing distances of the first and second spacers is controlled, thereby achieving the purpose of controlling the thickness of the mechanism portion of the first and second lenses. Since the spacing between the image-side surface of the first lens and the object-side surface of the second lens at the edge of the effective diameter is small, while ensuring uniform thickness of individual components, increasing the thickness of the lens mechanism portion can avoid interference between the first and second lenses due to assembly deformation, thus reducing the sensitivity of the optical system.

[0069] In this embodiment, among the multiple spacers, the one located between the second lens and the third lens and in at least partial contact with the image-side surface of the second lens is the second spacer. The radius of curvature R3 of the object-side surface of the second lens, the center thickness CT2 of the second lens on the optical axis, and the inner diameter d2s of the object-side surface of the second spacer satisfy the following: 0.99mm ≤ R3×CT2 / d2s ≤ 1.72mm. By limiting R3×CT2 / d2s within a reasonable range, and controlling the product of the radius of curvature of the object-side surface of the second lens and the ratio of the center thickness of the second lens on the optical axis to the inner diameter of the object-side surface of the second spacer, invalid light rays can be effectively blocked from passing through. Under the premise of meeting the design requirements, the field of view edge RI is improved, thereby improving the overall imaging quality of the optical system.

[0070] In this embodiment, among the multiple spacers, the one located between the second lens and the third lens and in at least partial contact with the image-side surface of the second lens is the second spacer. The radius of curvature R4 of the image-side surface of the second lens and the outer diameter D2s of the object-side surface of the second spacer satisfy the following relationship: -2.07 ≤ R4 / D2s ≤ -0.37. By limiting R4 / D2s within a reasonable range and controlling the ratio of the outer diameter of the object-side surface of the second spacer to the radius of curvature of the image-side surface of the second lens, it is possible to control the edge ray trajectory and shape of the second lens. At the same time, stray light generation can be avoided while ensuring optical parameters, thus guaranteeing image quality.

[0071] In this embodiment, among the multiple spacers, the one located between the second lens and the third lens and in at least partial contact with the image-side surface of the second lens is the second spacer. The center thickness CT2 of the second lens on the optical axis, the air gap T23 between the second and third lenses on the optical axis, and the maximum thickness CP2 of the second spacer satisfy the following: 6.01 ≤ CT2 / (T23+CP2) ≤ 6.29. By limiting CT2 / (T23+CP2) within a reasonable range, the ratio of the center thickness of the second lens on the optical axis to the sum of the air gap between the second and third lenses on the optical axis and the maximum thickness of the second spacer is controlled. This helps to reduce the sensitivity of the second and third lenses to tilt during assembly and improve the stability of the assembly performance of the second and third lenses.

[0072] In this embodiment, among the multiple spacers, the one located between the second lens and the third lens and in at least partial contact with the image-side surface of the second lens is the second spacer. The radius of curvature R5 of the object-side surface of the third lens satisfies the following relationship with the outer diameter D2m and inner diameter d2m of the image-side surface of the second spacer: 0.77 ≤ R5 / (D2m-d2m) ≤ 3.48. By limiting R5 / (D2m-d2m) within a reasonable range, the ratio of the radius of curvature of the object-side surface of the third lens to the difference between the outer and inner diameters of the image-side surface of the second spacer is controlled. This achieves the purpose of controlling the cantilever beam length of the second spacer, avoiding excessive cantilever beam length that could cause the second spacer to deform due to baking, thereby reducing the risk of aperture position shift in the optical system and ensuring the optical path.

[0073] In this embodiment, among the multiple spacers, the spacer located between the second and third lenses and in at least partial contact with the image-side surface of the second lens is the second spacer. The spacing distance EP23 between the second and third spacers along the optical axis and the center thickness CT3 of the third lens on the optical axis satisfy the following: 1.72 ≤ EP23 / CT3 ≤ 2.06. By limiting EP23 / CT3 within a reasonable range, the ratio of the spacing distance between the second and third spacers to the center thickness of the third lens on the optical axis is controlled, thereby controlling the divergence angle of light in the front lens group. Simultaneously, the overall shape transition of the second lens can be smoothly controlled, avoiding excessive thickness ratio fluctuations and increasing the forming stability of the second lens.

[0074] In this embodiment, the outer diameter D3s of the object side of the third spacer, the inner diameter d3s of the object side of the third spacer, and the radius of curvature R6 of the image side of the third lens satisfy the following relationship: 1.09 ≤ (D3s - d3s) / R6 ≤ 1.50. By limiting (D3s - d3s) / R6 within a reasonable range, the ratio of the difference between the outer and inner diameters of the object side of the third spacer to the radius of curvature of the image side of the third lens can be controlled. This controls the range of edge rays on the image side of the third lens, avoiding excessive divergence of edge rays on the image side of the third lens, which could lead to a higher risk of light leakage, thereby reducing the risk of stray light transmission on the image side of the third lens.

[0075] In this embodiment, the outer diameter D3m of the image-side surface of the third spacer and the radius of curvature R7 of the object-side surface of the fourth lens satisfy the following ratio: 0.95 ≤ D3m / R7 ≤ 2.69. By limiting D3m / R7 within a reasonable range and controlling the ratio of the outer diameter of the image-side surface of the third spacer to the radius of curvature of the object-side surface of the fourth lens, the risk of internal reflected light from the third lens entering the fourth lens through the engagement position and causing internal stray light in the fourth lens can be reduced when the third and fourth lenses are engaged, thus ensuring image cleanliness.

[0076] In this embodiment, the outer 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: -2.83 ≤ D4s / R8 ≤ -2.39. By limiting D4s / R8 within a reasonable range and controlling the ratio of the outer diameter of the object side of the fourth spacer to the radius of curvature of the image side of the fourth lens, the range of edge rays on the image side of the fourth lens can be controlled. Simultaneously, the fourth spacer can block internal reflection stray light from the fourth lens, reducing stray light energy on the imaging surface.

[0077] In this embodiment, the outer diameter D4m of the image-side surface of the fourth spacer, the inner diameter d4m of the image-side surface of the fourth spacer, and the radius of curvature R9 of the object-side surface of the fifth lens satisfy the following relationship: -1.83 ≤ (D4m - d4m) / R9 ≤ -1.41. By limiting (D4m - d4m) / R9 within a reasonable range, and controlling the ratio of the difference between the outer and inner diameters of the image-side surface of the fourth spacer to the radius of curvature of the object-side surface of the fifth lens, the cantilever beam length of the fourth spacer can be controlled. This avoids excessive cantilever beam length of the fourth spacer, which could lead to baking deformation of the fourth spacer, thereby reducing the risk of aperture position shift in the optical system.

[0078] Second Implementation Method

[0079] like Figures 1 to 20 As shown, the optical system includes a lens group, multiple spacers, and a lens barrel. The lens group has five lenses with optical power, and the lens group includes a first lens to a fifth lens sequentially from the object side to the image side of the optical system. Among the multiple spacers, the third spacer is located between the third and fourth lenses and is in at least partial contact with the image side of the third lens, and the fourth spacer is located between the fourth and fifth lenses and is in at least partial contact with the image side of the fourth lens. The lens barrel has a housing space, and the lens group and multiple spacers are housed in the housing space. The air gap T34 between the third and fourth lenses on the optical axis of the optical system and the air gap T45 between the fourth and fifth lenses on the optical axis satisfy the following: 4.9 ≤ T45 / T34 ≤ 6.99. The outer 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: -2.83 ≤ D4s / R8 ≤ -2.39.

[0080] In this application's five-element optical system, to balance the Petzval field curvature of the optical system, the fifth lens has a large surface curvature, resulting in a large edge-to-thickness ratio. Furthermore, it satisfies 4.9 ≤ T45 / T34 ≤ 6.99, increasing the risk of edge rays entering the fifth lens's structural portion and generating more internal reflection stray light, thus affecting image cleanliness. This application addresses this by controlling the ratio of the outer diameter of the object-side surface of the fourth spacer to the radius of curvature of the image-side surface of the fourth lens. This controls the range of edge rays from the image side of the fourth lens, preventing stray light from entering the fifth lens's structural portion. Simultaneously, the fourth spacer can block the internal reflection stray light from the fourth lens, reducing stray light energy on the imaging surface.

[0081] It should be noted that this embodiment may also include other conditional expressions from the above embodiments, which will not be elaborated here.

[0082] Optionally, the optical system may also include protective glass for protecting the photosensitive element located on the imaging surface.

[0083] The optical system in this application may employ multiple lenses, such as the seven 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.

[0084] 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 seven lenses have been described as an example in the embodiments, the optical system is not limited to including seven lenses. If necessary, the optical system may also include other numbers of lenses.

[0085] Figure 1 A schematic diagram showing the dimensions of an optical system according to this application is provided. Figure 1 The parameters D1s, d4m, EP23, etc., are indicated to provide a clear and intuitive understanding of their meaning. To facilitate the description of the optical system and the surface shape of specific lenses, these parameters will not be shown in the accompanying drawings when describing specific embodiments.

[0086] It should be noted that in an optical system, the surface closest to the object side at the object-side end of the lens tube is the object-side end face of the lens tube, and the surface closest to the image side at the image-side end of the lens tube is the image-side end face of the lens tube.

[0087] Optionally, the optical system in the embodiments of this application can be simulated using software and / or tools such as ZEMAX and CODEV. Alternatively, the optical system can be simulated using CODEV software. During the simulation process using such software and / or tools, the surface profile of each lens can be appropriately adjusted based on the surface profile of the software and / or tool used.

[0088] In this embodiment, each lens can be optionally configured as a tangent lens. The outer diameter surface of the tangent lens has a tangent structure and a non-tangent structure, with the outer diameter of the tangent structure being smaller than the outer diameter of the non-tangent structure. The outer diameter of the tangent lens typically refers to the outer diameter of the non-tangent structure.

[0089] In this embodiment, each spacer can be optionally configured as a chamfered spacer. The outer circumferential surface of the chamfered spacer has a chamfered portion and a non-chamfered portion, and the outer diameter of the chamfered portion is smaller than the outer diameter of the non-chamfered portion. The outer diameter of the chamfered spacer typically refers to the maximum outer diameter of the non-chamfered portion.

[0090] 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.

[0091] It should be noted that any one of the following embodiments, from Embodiment 1 to Embodiment 9, is applicable to all implementation methods of this application.

[0092] Example 1

[0093] like Figure 2 The optical system of Embodiment 1 of this application is described in the figure. Figure 2 A schematic diagram of the optical system of Embodiment 1 is shown.

[0094] like Figure 2 As shown, the optical system includes, from the object side to the image side, the following components housed within the lens barrel P0: a first lens E1, a first spacer P1, a second lens E2, a second spacer P2, a third lens E3, a third spacer P3, a fourth lens E4, a fourth spacer P4, a fifth lens E5, and a fifth spacer P5.

[0095] In this embodiment, the first lens E1 has negative optical power, its object-side surface S1 is convex, and its image-side surface S2 is concave. The second lens E2 has positive optical power, its object-side surface S3 is convex, and its image-side surface S4 is convex. The third lens E3 has negative optical power, its object-side surface S5 is convex, and its image-side surface S6 is concave. The fourth lens E4 has positive optical power, its object-side surface S7 is convex, and its image-side surface S8 is convex. The fifth lens E5 has negative optical power, its object-side surface S9 is concave, and its image-side surface S10 is concave. The optical system also includes a filter or protective glass (not shown in the figure), which has an object-side surface S13 (not shown in the figure) and an image-side surface S14 (not shown in the figure). Light rays from the object surface pass through S1 to S14 to reach the imaging surface S15 (not shown in the figure).

[0096] Table 2 shows the basic structural parameters of the optical system in Embodiment 1, where the units for radius of curvature, thickness / distance, effective radius, and focal length are all millimeters (mm). OBJ (not shown in the figure) is the object plane, and the aperture stop is located between the first lens and the second lens.

[0097] Table 2

[0098]

[0099]

[0100] In Embodiment 1, all lenses are aspherical lenses, and the shape of the aspherical surface can be defined using, but is not limited to, the following aspherical formula:

[0101]

[0102] 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, that is, the paraxial curvature c is the reciprocal of the radius of curvature R in Table 2 above; k is the conic coefficient; Ai is the i-th order correction coefficient of the aspherical surface. Table 3 below gives the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A24, A26, A28, A30 that can be used for each aspherical mirror S1-S10 in Example 1.

[0103] Table 3

[0104]

[0105]

[0106] Figure 3 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 4 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 5 The magnification chromatic aberration curve of the optical system of Embodiment 1 is shown, which represents the degree to which the focal points of light of different wavelengths do not completely coincide.

[0107] according to Figures 3 to 5 As can be seen, the optical system given in Example 1 can achieve good imaging quality.

[0108] Example 2

[0109] like Figure 6 The image shows an optical system according to Embodiment 2 of this application. The optical system of this embodiment has the same optical parameters and the same arrangement of lenses and spacers as Embodiment 1, but the structural parameters are different. Please refer to the relevant description in Embodiment 1; it will not be repeated here.

[0110] Example 3

[0111] like Figure 7 The image shows an optical system according to Embodiment 3 of this application. The optical system of this embodiment has the same optical parameters and the same arrangement of lenses and spacers as that of Embodiment 1, but the structural parameters are different. Please refer to the relevant description in Embodiment 1, which will not be repeated here.

[0112] Example 4

[0113] like Figure 8 As shown, an optical system according to Embodiment 4 of this application is described. Figure 8A schematic diagram of the optical system of Embodiment 4 is shown.

[0114] like Figure 8 As shown, the optical system includes, from the object side to the image side, the following components housed within the lens barrel P0: a first lens E1, a first spacer P1, a second lens E2, a second spacer P2, a third lens E3, a third spacer P3, a fourth lens E4, a fourth spacer P4, a fifth lens E5, and a fifth spacer P5.

[0115] In this embodiment, the first lens E1 has negative optical power, its object-side surface S1 is convex, and its image-side surface S2 is concave. The second lens E2 has positive optical power, its object-side surface S3 is convex, and its image-side surface S4 is concave. The third lens E3 has negative optical power, its object-side surface S5 is convex, and its image-side surface S6 is concave. The fourth lens E4 has positive optical power, its object-side surface S7 is convex, and its image-side surface S8 is convex. The fifth lens E5 has negative optical power, its object-side surface S9 is concave, and its image-side surface S10 is concave. The optical system also includes a filter or protective glass (not shown in the figure), which has an object-side surface S13 (not shown in the figure) and an image-side surface S14 (not shown in the figure). Light rays from the object surface pass through S1 to S14 to reach the imaging surface S15 (not shown in the figure).

[0116] Table 4 shows the basic structural parameters of the optical system in Embodiment 4, where the units for radius of curvature, thickness / distance, effective radius, and focal length are all millimeters (mm). OBJ (not shown in the figure) is the object plane, and the aperture stop is located between the first lens and the second lens.

[0117] Table 4

[0118] OBJ spherical endless endless S1 aspherical 10.0000 0.3800 1.63 23.3 0.0000 S2 aspherical 2.7505 0.4747 0.0000 STO spherical endless 0.0800 S3 aspherical 4.4652 0.7119 1.54 55.9 0.0000 S4 aspherical -2.6501 0.0950 0.0000 S5 aspherical 1.9732 0.3300 1.67 19.2 0.0000 S6 aspherical 1.7930 0.0800 0.0000 S7 aspherical 1.8464 1.0000 1.54 55.9 0.0000 S8 aspherical -1.9444 0.4374 0.0000 S9 aspherical -1.3990 0.4500 1.67 19.2 -8.4711 S10 aspherical 3.1419 0.0910 -2.5487 S13 spherical endless 0.1700 1.52 64.2 S14 spherical endless 0.4000 S15 spherical endless

[0119] In Example 4, all lenses are aspherical lenses, and the shape of the aspherical surface can be defined using, but is not limited to, formula (1) in Example 1. Table 5 below gives the higher-order coefficients of each aspherical mirror S1-S10 that can be used in Example 4.

[0120] Table 5

[0121] S1 1.8074E-01 -1.0485E-02 -9.5390E-04 -8.8409E-04 -4.2990E-05 -7.5915E-05 -7.8788E-05 S2 1.7108E-01 2.5358E-02 9.6828E-03 2.5016E-03 9.8938E-04 8.7591E-05 7.5104E-05 S3 3.5883E-03 -2.5394E-04 1.3301E-04 4.7864E-05 -2.7442E-05 -4.3655E-06 -1.0749E-05 S4 -1.5532E-01 1.4340E-02 -2.3398E-03 1.4162E-03 -1.3397E-04 2.0154E-04 8.2260E-05 S5 -1.5636E-01 1.0387E-02 -5.0106E-03 1.3210E-03 -4.4042E-04 1.0903E-04 -4.5759E-05 S6 -3.3842E-01 1.4014E-02 -1.5612E-02 1.2223E-03 -2.8600E-03 1.2588E-04 -7.1003E-05 S7 -2.9136E-01 3.0879E-02 -4.4997E-03 3.7685E-03 -1.2494E-03 -1.5704E-04 -1.3763E-04 S8 -1.2990E-01 7.2416E-03 1.5770E-02 4.2618E-03 3.1975E-03 1.0148E-03 5.3038E-04 S9 -7.4183E-01 1.8137E-01 -8.8529E-03 2.4921E-03 3.0597E-03 2.0829E-03 -9.3528E-04 S10 -9.5009E-01 2.4797E-01 -5.5276E-02 -1.8614E-03 -5.9185E-03 4.5753E-04 -3.5729E-03 Face number A18 A20 A22 A24 A26 A28 A30 S1 -5.9255E-05 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S2 -3.8988E-05 7.8693E-05 3.0023E-05 4.9690E-05 0.0000E+00 0.0000E+00 0.0000E+00 S3 2.0372E-05 1.4696E-05 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S4 2.7228E-05 2.9123E-05 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S5 1.8610E-05 -3.3552E-06 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S6 4.5051E-05 -5.8242E-05 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S7 6.6509E-05 -1.0361E-05 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S8 1.3212E-05 6.0759E-06 -9.0658E-05 -2.2979E-05 -5.2100E-05 -2.2831E-06 0.0000E+00 S9 -5.7234E-05 -2.2079E-04 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S10 -7.2561E-04 -6.9187E-04 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00

[0122] Figure 9 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 10 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 11The magnification chromatic aberration curve of the optical system of Embodiment 4 is shown, which represents the degree to which the focal points of light of different wavelengths do not completely coincide.

[0123] according to Figures 9 to 11 As can be seen, the optical system given in Example 4 can achieve good imaging quality.

[0124] Example 5

[0125] like Figure 12 The image shows an optical system according to Embodiment 5 of this application. The optical system of this embodiment has the same optical parameters and the same arrangement of lenses and spacers as that of Embodiment 4, but the structural parameters are different. Please refer to the relevant description in Embodiment 4; it will not be repeated here.

[0126] Example 6

[0127] like Figure 13 The image shows an optical system according to Embodiment Six of this application. The optical system of this embodiment has the same optical parameters and the same arrangement of lenses and spacers as that of Embodiment Four, but the structural parameters are different. Please refer to the relevant description in Embodiment Four; it will not be repeated here.

[0128] Example 7

[0129] like Figure 14 As shown, an optical system according to Embodiment Seven of this application is described. Figure 14 A schematic diagram of the optical system of Embodiment Seven is shown.

[0130] like Figure 14 As shown, the optical system includes, from the object side to the image side, the following components housed within the lens barrel P0: a first lens E1, a first spacer P1, a second lens E2, a second spacer P2, a third lens E3, a third spacer P3, a fourth lens E4, a fourth spacer P4, a fifth lens E5, and a fifth spacer P5.

[0131] In this embodiment, the first lens E1 has negative optical power, its object-side surface S1 is convex, and its image-side surface S2 is concave. The second lens E2 has positive optical power, its object-side surface S3 is convex, and its image-side surface S4 is convex. The third lens E3 has negative optical power, its object-side surface S5 is convex, and its image-side surface S6 is concave. The fourth lens E4 has positive optical power, its object-side surface S7 is convex, and its image-side surface S8 is convex. The fifth lens E5 has negative optical power, its object-side surface S9 is concave, and its image-side surface S10 is concave. The optical system also includes a filter or protective glass (not shown in the figure), which has an object-side surface S13 (not shown in the figure) and an image-side surface S14 (not shown in the figure). Light rays from the object surface pass through S1 to S14 to reach the imaging surface S15 (not shown in the figure).

[0132] Table 6 shows the basic structural parameters of the optical system in Embodiment 7, where the units for radius of curvature, thickness / distance, effective radius, and focal length are all millimeters (mm). OBJ (not shown in the figure) is the object plane, and the aperture stop is located between the first lens and the second lens.

[0133] Table 6

[0134]

[0135]

[0136] In Example 7, all lenses are aspherical lenses, and the shape of the aspherical surface can be defined using, but is not limited to, the formula (1) in Example 1. Table 7 below gives the higher-order coefficients of each aspherical mirror S1-S10 that can be used in Example 7.

[0137] Table 7

[0138]

[0139] Figure 15 The on-axis chromatic aberration curve of the optical system of Embodiment 7 is shown, which represents the deviation of the focal point of light of different wavelengths after passing through the optical system. Figure 16 The astigmatism curves of the optical system of Embodiment 7 are shown, which represent the meridional image plane curvature and the sagittal image plane curvature. Figure 17 The magnification chromatic aberration curve of the optical system of Embodiment 7 is shown, which represents the degree to which the focal points of light of different wavelengths do not completely coincide.

[0140] according to Figures 15 to 17 It can be seen that the optical system given in Example 7 can achieve good imaging quality.

[0141] Example 8

[0142] like Figure 18 The image shows an optical system according to Embodiment 8 of this application. The optical system of this embodiment has the same optical parameters and the same arrangement of lenses and spacers as that of Embodiment 7, but the structural parameters are different. Please refer to the relevant description in Embodiment 7, which will not be repeated here.

[0143] Example 9

[0144] like Figure 19 The image shows an optical system according to Embodiment Nine of this application. The optical system of this embodiment has the same optical parameters and the same arrangement of lenses and spacers as that of Embodiment Seven, but the structural parameters are different. Please refer to the relevant description in Embodiment Seven; it will not be repeated here.

[0145] In summary, embodiments one through nine of the optical system satisfy the relationships shown in Table 8.

[0146] Table 8

[0147] R1 / (d0s-d1s) 2.87 2.83 2.87 3.78 3.60 3.64 3.45 3.30 3.42 f1 / (EP01+CT1) -4.83 -4.87 -4.79 -4.25 -4.31 -4.45 -2.93 -2.97 -3.06 R2 / (D1s-d1s) 0.86 0.86 1.27 1.02 0.98 1.39 0.70 0.67 1.15 f2 / (T12+EP12) 2.79 2.81 2.83 2.75 2.73 2.75 1.29 1.29 1.29 R3×CT2 / d2s 0.99 1.00 1.00 1.69 1.69 1.72 1.15 1.16 1.16 R4 / D2s -1.66 -1.68 -2.07 -0.61 -0.60 -0.78 -0.38 -0.37 -0.51 CT2 / (T23+CP2) 6.29 6.29 6.29 6.08 6.08 6.08 6.01 6.01 6.01 R5 / (D2m-d2m) 0.77 0.78 1.17 0.80 0.77 1.26 1.92 1.84 3.48 EP23 / CT3 2.02 1.99 2.06 1.82 1.82 1.95 1.72 1.72 1.87 (D3s-d3s) / R6 1.47 1.50 1.47 1.31 1.37 1.34 1.09 1.13 1.09 CT4 / EP34 1.83 1.67 1.79 2.03 1.95 1.92 1.60 1.47 1.53 T45 / T34 6.99 6.99 6.99 5.47 5.47 5.47 4.90 4.90 4.90 D3m / R7 2.67 2.69 2.68 2.49 2.55 2.51 0.95 0.97 0.95 D4s / R8 -2.81 -2.83 -2.82 -2.53 -2.59 -2.56 -2.39 -2.44 -2.39 (D4m-d4m) / R9 -1.70 -1.74 -1.71 -1.77 -1.83 -1.80 -1.41 -1.46 -1.41

[0148] Table 9 provides the optical parameters of the optical systems in Examples 1 to 9. Wherein, TTL is the total length of the optical system, specifically the distance along the optical axis from the object side of the first lens to the imaging surface of the optical system; ImgH is the image height of the optical system, specifically half the diagonal length of the effective pixel area on the imaging surface of the optical system, 2.24mm≤ImgH≤2.30mm; Semi-FOV is half the maximum field of view of the optical system, 63.00°≤Semi-FOV≤65.00°; Fno is the F-number of the optical system; and f is the total focal length of the optical system.

[0149] Table 9

[0150]

[0151]

[0152] Table 10 provides the parameters of each spacer in the optical systems of Examples 1 to 9, in mm.

[0153] Table 10

[0154] d1s 1.534 1.494 1.550 1.423 1.389 1.303 1.399 1.365 1.368 D1s 4.420 4.380 3.513 4.110 4.210 3.284 4.240 4.340 3.087 d2s 1.914 1.908 1.908 1.882 1.885 1.852 1.895 1.889 1.884 d2m 1.914 1.908 1.908 1.882 1.885 1.852 1.895 1.889 1.884 D2s 4.620 4.580 3.703 4.344 4.444 3.414 4.460 4.560 3.297 D2m 4.620 4.580 3.703 4.344 4.444 3.414 4.460 4.560 3.297 d3s 2.100 2.086 2.106 2.248 2.246 2.244 2.114 2.103 2.114 D3s 4.750 4.790 4.770 4.600 4.700 4.640 4.680 4.780 4.680 D3m 4.750 4.790 4.770 4.600 4.700 4.640 4.680 4.780 4.680 d4m 2.550 2.540 2.554 2.447 2.463 2.449 2.202 2.212 2.202 D4s 4.920 4.960 4.940 4.928 5.028 4.968 4.860 4.960 4.860 D4m 4.920 4.960 4.940 4.928 5.028 4.968 4.860 4.960 4.860 d0s 4.322 4.322 4.342 4.069 4.169 4.050 4.294 4.394 4.294 EP01 1.052 1.042 1.062 1.065 1.045 0.999 1.228 1.208 1.165 EP12 0.596 0.586 0.576 0.596 0.606 0.597 0.734 0.734 0.733 EP23 0.566 0.556 0.576 0.599 0.599 0.643 0.638 0.638 0.692 EP34 0.508 0.558 0.518 0.492 0.512 0.522 0.456 0.496 0.476 CP2 0.022 0.022 0.022 0.022 0.022 0.022 0.022 0.022 0.022

[0155] 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.

[0156] Obviously, the embodiments described above are merely some, not all, embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0157] 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.

[0158] 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.

[0159] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An optical system, characterized in that, include: A lens group comprising five lenses of optical power, comprising, sequentially from the object side to the image side of the optical system, a first lens to a fifth lens. The first lens has negative optical power, with a convex object side and a concave image side. The second lens has positive optical power, with both its object and image sides being convex. The third lens has negative optical power, with both its object and image sides being convex. The fourth lens has positive optical power, with both its object and image sides being convex. The fifth lens has negative optical power, with both its object and image sides being concave. A plurality of spacers, wherein the spacer located between the third lens and the fourth lens and in at least partial contact with the image-side surface of the third lens is the third spacer, and the spacer located between the fourth lens and the fifth lens and in at least partial contact with the image-side surface of the fourth lens is the fourth spacer; A lens barrel having a receiving space, in which the lens group and the plurality of spacers are housed; Wherein, the air gap T34 between the third lens and the fourth lens on the optical axis of the optical system, and the air gap T45 between the fourth lens and the fifth lens on the optical axis satisfy the following: 4.9≤T45 / T34≤6.99; The central thickness CT4 of the fourth lens on the optical axis and the spacing EP34 between the third spacer and the fourth spacer along the optical axis satisfy the following condition: 1.47≤CT4 / EP34≤2.03; The outer diameter D3m of the image side of the third spacer and the radius of curvature R7 of the object side of the fourth lens satisfy the following condition: 0.95≤D3m / R7≤2.

69.

2. The optical system according to claim 1, characterized in that, Among the plurality of spacers, the spacer located between the first lens and the second lens and in at least partial contact with the image side of the first lens is the first spacer. The radius of curvature R1 of the object side of the first lens, the inner diameter d0s of the object side end face of the lens barrel, and the inner diameter d1s of the object side of the first spacer satisfy the following: 2.83≤R1 / (d0s-d1s)≤3.

78.

3. The optical system according to claim 1, characterized in that, Among the plurality of spacers, the spacer located between the first lens and the second lens and in at least partial contact with the image side of the first lens is the first spacer. The radius of curvature R2 of the image side of the first lens, the outer diameter D1s of the object side of the first spacer, and the inner diameter d1s of the object side of the first spacer satisfy the following: 0.67≤R2 / (D1s-d1s)≤1.

39.

4. The optical system according to claim 1, characterized in that, Among the plurality of spacers, the spacer located between the first lens and the second lens and in at least partial contact with the image side surface of the first lens is the first spacer. The effective focal length f1 of the first lens, the spacing distance EP01 from the object side end face of the lens barrel to the object side surface of the first spacer along the optical axis, and the center thickness CT1 of the first lens on the optical axis satisfy the following: -4.87≤f1 / (EP01+CT1)≤-2.

93.

5. The optical system according to claim 1, characterized in that, Among the plurality of spacers, the spacer located between the first lens and the second lens and in at least partial contact with the image side of the first lens is the first spacer, and the spacer located between the second lens and the third lens and in at least partial contact with the image side of the second lens is the second spacer. The effective focal length f2 of the second lens, the air gap T12 between the first lens and the second lens on the optical axis, and the spacing EP12 between the first spacer and the second spacer along the optical axis satisfy the following: 1.29≤f2 / (T12+EP12)≤2.

83.

6. The optical system according to claim 1, characterized in that, Among the plurality of spacers, the spacer located between the second lens and the third lens and in at least partial contact with the image side of the second lens is the second spacer. The radius of curvature R3 of the object side of the second lens, the center thickness CT2 of the second lens on the optical axis, and the inner diameter d2s of the object side of the second spacer satisfy the following: 0.99mm≤R3×CT2 / d2s≤1.72mm.

7. The optical system according to claim 1, characterized in that, Among the plurality of spacers, the spacer located between the second lens and the third lens and in at least partial contact with the image side of the second lens is the second spacer. The radius of curvature R4 of the image side of the second lens and the outer diameter D2s of the object side of the second spacer satisfy the following: -2.07≤R4 / D2s≤-0.

37.

8. The optical system according to claim 1, characterized in that, Among the plurality of spacers, the spacer located between the second lens and the third lens and in at least partial contact with the image side of the second lens is the second spacer. The center thickness CT2 of the second lens on the optical axis, the air gap T23 between the second lens and the third lens on the optical axis, and the maximum thickness CP2 of the second spacer satisfy the following: 6.01≤CT2 / (T23+CP2)≤6.

29.

9. The optical system according to claim 1, characterized in that, Among the plurality of spacers, the spacer located between the second lens and the third lens and in at least partial contact with the image-side surface of the second lens is the second spacer. The radius of curvature R5 of the object-side surface of the third lens satisfies the following relationship with the outer diameter D2m of the image-side surface of the second spacer and the inner diameter d2m of the image-side surface of the second spacer: 0.77≤R5 / (D2m-d2m)≤3.

48.

10. The optical system according to claim 1, characterized in that, Among the plurality of spacers, the spacer located between the second lens and the third lens and in at least partial contact with the image side of the second lens is the second spacer. The distance EP23 between the second spacer and the third spacer along the optical axis and the center thickness CT3 of the third lens on the optical axis satisfy the following: 1.72≤EP23 / CT3≤2.

06.

11. The optical system according to claim 1, characterized in that, The outer diameter D3s of the object side of the third spacer, the inner diameter d3s of the object side of the third spacer, and the radius of curvature R6 of the image side of the third lens satisfy the following condition: 1.09≤(D3s-d3s) / R6≤1.

50.

12. The optical system according to claim 1, characterized in that, The outer 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 condition: -2.83≤D4s / R8≤-2.

39.

13. The optical system according to claim 1, characterized in that, The outer diameter D4m of the image side of the fourth spacer, the inner diameter d4m of the image side of the fourth spacer, and the radius of curvature R9 of the object side of the fifth lens satisfy the following: -1.83≤(D4m-d4m) / R9≤-1.41.

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