Imaging system

Abstract

The application discloses an imaging system, comprising: a lens group, comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens arranged in order from an object side to an image side along an optical axis, a radius of curvature of an image side surface of the fifth lens is greater than zero; a plurality of spacer elements, comprising: a fourth spacer element in partial contact with an image side surface of the fourth lens, a fifth spacer element, wherein an inner diameter of an object side surface and an inner diameter of an image side surface of at least one of the plurality of spacer elements are not equal and / or an outer diameter of the object side surface and an outer diameter of the image side surface are not equal; and a lens barrel accommodating the lens group and the plurality of spacer elements, a difference between an outer diameter of the image side surface and an outer diameter of the object side surface of the lens barrel is greater than 3.5 mm. The imaging system satisfies: -14.0<(D5m+D4m) / (R7+R10)<-5.5.

Description

[0001] Divisional application statement

[0002] This application is a divisional application of Chinese invention patent application filed on August 3, 2022, entitled "Imaging System" and with application number 202210926164.1. Technical Field

[0003] This application relates to the field of optical components, and more specifically, to an imaging system. Background Technology

[0004] With technological advancements, mobile phones have become an indispensable part of people's lives. People have increasingly higher demands for the image quality of mobile phone cameras, and the quality of a phone's camera performance is gradually becoming a decisive factor when choosing a phone. The image quality of a camera mainly depends on the overall length of the lens, the aperture, and the size of the lens itself.

[0005] Currently, the image quality of front-facing cameras on most mobile phones on the market is generally poor, mainly due to the characteristics of front-facing cameras. The size of the front-facing camera lens determines the size of the screen cutout, and this size is related to the lens's aperture and overall length. The ratio of overall length to image height determines the relative length of the lens. Therefore, for a front-facing camera, its aperture size and overall lens length determine its lens size, which in turn determines the size of the screen cutout.

[0006] Currently, mobile phone front-facing cameras generally have large apertures (FNO>2). A larger aperture means a smaller overall aperture, resulting in less light intake and poor image quality in low-light conditions. Furthermore, the air gaps between different lenses within the lens complicate the stability and manufacturing process of some lenses. Therefore, achieving a relatively large aperture while maintaining a small overall lens length and compact size, and addressing the difficulties in lens manufacturing and stability, are crucial for improving the image quality of camera lenses. Summary of the Invention

[0007] This application provides an imaging system, comprising: a lens group including a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged sequentially along the optical axis from the object side to the image side, wherein the second lens and the fifth lens have negative optical power, the fourth lens has positive optical power, and the radius of curvature of the image-side surface of the fifth lens is greater than zero; and a plurality of spacer elements, including: a second spacer element in contact with the image-side surface of the second lens, a third spacer element in contact with the image-side surface of the third lens, a fourth spacer element in contact with the image-side surface of the fourth lens, and a fifth spacer element in contact with the image-side surface of the fifth lens. The side portion contacts, wherein at least one of the plurality of spacers has an object-side inner diameter that is not equal to its image-side inner diameter and / or an object-side outer diameter that is not equal to its image-side outer diameter; and a lens barrel that houses the lens group and the plurality of spacers, wherein the difference between the image-side outer diameter and the object-side outer diameter of the lens barrel is greater than 3.5 mm; the imaging system satisfies: 3.5 < (R3 + R10) / (D5m - D2m) < 16.0, where D5m is the image-side outer diameter of the fifth spacer, D2m is the image-side outer diameter of the second spacer, R10 is the radius of curvature of the image-side surface of the fifth lens, and R3 is the radius of curvature of the object-side surface of the second lens.

[0008] In one embodiment, the imaging system satisfies: f1 / f3>0; and R5 / R6>0, where f1 is the effective focal length of the first lens, f3 is the effective focal length of the third lens, R5 is the radius of curvature of the object-side surface of the third lens, and R6 is the radius of curvature of the image-side surface of the third lens.

[0009] In one embodiment, the plurality of spacers further includes a first spacer element that contacts the image-side portion of the first lens.

[0010] In one embodiment, the imaging system satisfies: R7 / R9<0, where R7 is the radius of curvature of the object-side surface of the fourth lens and R9 is the radius of curvature of the object-side surface of the fifth lens.

[0011] In one embodiment, the imaging system satisfies: 4.0 < (d5m - D2s + d4m) / (CT2 + CT4 + CT5) < 8.5, where d5m is the inner diameter of the image side of the fifth spacer element, D2s is the outer diameter of the object side of the second spacer element, d4m is the inner diameter of the image side of the fourth spacer element, CT2 is the center thickness of the second lens, CT4 is the center thickness of the fourth lens, and CT5 is the center thickness of the fifth lens.

[0012] In one embodiment, the imaging system satisfies: 15.0 < d2m / T23 + d3m / T34 < 19.5, wherein d2m is the inner diameter of the image side surface of the second spacer element, T23 is the air gap between the second lens and the third lens on the optical axis, d3m is the inner diameter of the image side surface of the third spacer element, and T34 is the air gap between the third lens and the fourth lens on the optical axis.

[0013] In one embodiment, the imaging system satisfies: 15.5 < (f4-f5) / (CP5+CP4) < 35.5, wherein f4 is the effective focal length of the fourth lens, f5 is the effective focal length of the fifth lens, CP5 is the maximum thickness of the fifth spacer element, and CP4 is the maximum thickness of the fourth spacer element.

[0014] In one embodiment, the imaging system satisfies: -41.0mm 2 <(TD+L)*(f5+CP5)<-33.5mm 2 , wherein TD is the distance from the object side of the first lens to the image side of the sixth lens on the optical axis, L is the maximum dimension of the lens barrel along the optical axis direction, f5 is the effective focal length of the fifth lens, and CP5 is the maximum thickness of the fifth spacer element.

[0015] In one embodiment, the imaging system satisfies: 16.5 < (d4s+d2s) / (T45+T23) < 23.5, wherein d4s is the inner diameter of the object side surface of the fourth spacer element, d2s is the inner diameter of the object side surface of the second spacer element, T23 is the air gap between the second lens and the third lens on the optical axis, and T45 is the air gap between the fourth lens and the fifth lens on the optical axis.

[0016] In one embodiment, the imaging system satisfies: -4.0 < R9 / R8 + d4s / (CP4*10) < 16.5, wherein R9 is the curvature radius of the object side surface of the fifth lens, R8 is the curvature radius of the image side surface of the fourth lens, d4s is the inner diameter of the object side surface of the fourth spacer element, and CP4 is the maximum thickness of the fourth spacer element.

[0017] In one embodiment, the imaging system satisfies: 17.0 < (D5s+d5s) / (CT5+T56) < 21.0, wherein D5s is the outer diameter of the object side of the fifth spacer element, d5s is the inner diameter of the object side of the fifth spacer element, CT5 is the center thickness of the fifth lens, and T56 is the air gap between the fifth lens and the sixth lens on the optical axis.

[0018] In one embodiment, the imaging system satisfies: 7.5 < EP25 / EP34 + TD / CT4 < 11.5, wherein EP25 is the distance between the second spacing element and the fifth spacing element, EP34 is the distance between the third spacing element and the fourth spacing element, TD is the distance on the optical axis from the object-side surface of the first lens to the image-side surface of the sixth lens, and CT4 is the center thickness of the fourth lens.

[0019] In one embodiment, the imaging system satisfies: -14.0 < (D5m+D4m) / (R7+R10) < -5.5, wherein D5m is the outer diameter of the image-side surface of the fifth spacing element, D4m is the outer diameter of the image-side surface of the fourth spacing element, R7 is the curvature radius of the object-side surface of the fourth lens, and R10 is the curvature radius of the image-side surface of the fifth lens.

[0020] In one embodiment, the imaging system satisfies: 23.5 < (∑CT-CPmax) / CPave * FNO < 59.0, wherein ∑CT is the sum of center thicknesses of all lenses from the first lens to the sixth lens, CPmax is the maximum value among the maximum thicknesses of all the spacing elements, CPave is the average value of the maximum thicknesses of all the spacing elements, and FNO is the f-number of the imaging system.

[0021] In one embodiment, the imaging system satisfies: 2.5 < (D0s+D0m) / f * tan(Semi-FOV) < 4.5, wherein D0s is the outer diameter of the object-side surface of the lens barrel, D0m is the outer diameter of the image-side surface of the lens barrel, f is the effective focal length of the imaging system, and Semi-FOV is half of the maximum field angle of the imaging system.

[0022] In one embodiment, the imaging system satisfies: 2.4 < (CT2+CT4) / (CP2+CP4) < 18.0, wherein CP4 is the maximum thickness of the fourth spacing element, CP2 is the maximum thickness of the second spacing element, CT2 is the center thickness of the second lens, and CT4 is the center thickness of the fourth lens.

[0023] In one embodiment, the imaging system satisfies: 3.5 < |(CT3+CT5) / (EP45-EP23)| < 11.5, wherein CT3 is the center thickness of the third lens, CT5 is the center thickness of the fifth lens, EP45 is the distance between the fourth spacing element and the fifth spacing element, and EP23 is the distance between the second spacing element and the third spacing element.

[0024] In one embodiment, materials of the first lens to the sixth lens are all plastics.

[0025] This application also provides an imaging system, comprising: a lens group including a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged sequentially along the optical axis from the object side to the image side, wherein the radius of curvature of the image side surface of the fifth lens is greater than zero; a plurality of spacer elements, including: a fourth spacer element in contact with the image side surface portion of the fourth lens, and a fifth spacer element in contact with the image side surface portion of the fifth lens, wherein at least one of the plurality of spacer elements has an object side surface inner diameter that is not equal to the image side surface inner diameter and / or an object side surface outer diameter that is not equal to the image side surface outer diameter; and a lens barrel housing the lens group and the plurality of spacer elements, wherein the difference between the image side surface outer diameter and the object side surface outer diameter of the lens barrel is greater than 3.5 mm. The imaging system satisfies: -14.0 < (D5m + D4m) / (R7 + R10) < -5.5, where D5m is the outer diameter of the image side of the fifth spacer element, D4m is the outer diameter of the image side of the fourth spacer element, R7 is the radius of curvature of the object side of the fourth lens, and R10 is the radius of curvature of the image side of the fifth lens.

[0026] This application, in another aspect, provides an imaging system comprising: a lens group including a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged sequentially along the optical axis from the object side to the image side, wherein the fifth lens has negative optical power, the fourth lens has positive optical power, and the radius of curvature of the image side surface of the fifth lens is greater than zero; a plurality of spacer elements, including: a fourth spacer element in contact with the image side surface portion of the fourth lens, and a fifth spacer element in contact with the image side surface portion of the fifth lens, wherein at least one of the plurality of spacer elements has an object side surface inner diameter that is not equal to the image side surface inner diameter and / or an object side surface outer diameter that is not equal to the image side surface outer diameter; and a lens barrel housing the lens group and the plurality of spacer elements, wherein the difference between the image side surface outer diameter and the object side surface outer diameter of the lens barrel is greater than 3.5 mm. The imaging system satisfies: 15.5 < (f4 - f5) / (CP5 + CP4) < 35.5, where f4 is the effective focal length of the fourth lens, f5 is the effective focal length of the fifth lens, CP5 is the maximum thickness of the fifth spacer element, and CP4 is the maximum thickness of the fourth spacer element.

[0027] This application employs a six-element lens architecture. By controlling the difference in the outer diameter of the image side of the fifth spacer element and the second spacer element within a reasonable range, it helps to reduce the outer diameter of the first four lenses, ensuring a smaller head size of the lens barrel. This results in a smaller opening size for the phone screen, a larger screen-to-body ratio, and reduced stray light. By rationally setting the difference between the curvature radius of the fifth lens's image side and the curvature radius of the second lens's object side, the curvature of the two lenses is effectively controlled, altering light refraction and increasing the amount of light entering the lens, thus ensuring adequate relative illumination. Through these comprehensive controls, structural requirements can be met while maintaining a small head size. The rational setting of the spacer elements enhances the overall strength and stability of the lens and facilitates the molding process of individual lenses. Attached Figure Description

[0028] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0029] Figure 1 A schematic diagram of an imaging system according to Embodiment 1 of this application is shown;

[0030] Figure 2 A schematic diagram of another imaging system according to Embodiment 1 of this application is shown;

[0031] Figure 3 A schematic diagram of another imaging system according to Embodiment 1 of this application is shown;

[0032] Figures 4A to 4D The on-axis chromatic aberration curve, astigmatism curve, distortion curve, and magnification chromatic aberration curve of the imaging system of Example 1 are shown respectively.

[0033] Figure 5 A schematic diagram of an imaging system according to Embodiment 2 of this application is shown;

[0034] Figure 6 A schematic diagram of another imaging system according to Embodiment 2 of this application is shown;

[0035] Figure 7 A schematic diagram of another imaging system according to Embodiment 2 of this application is shown;

[0036] Figures 8A to 8D The on-axis chromatic aberration curve, astigmatism curve, distortion curve, and magnification chromatic aberration curve of the imaging system of Example 2 are shown respectively.

[0037] Figure 9 A schematic diagram of an imaging system according to Embodiment 3 of this application is shown;

[0038] Figure 10A schematic diagram of another imaging system according to Embodiment 3 of this application is shown;

[0039] Figure 11 A schematic diagram of another imaging system according to Embodiment 3 of this application is shown;

[0040] Figures 12A to 12D The on-axis chromatic aberration curve, astigmatism curve, distortion curve, and magnification chromatic aberration curve of the imaging system of Example 3 are shown respectively; and

[0041] Figure 13 A schematic diagram showing the parameter annotations of the imaging system according to this application is provided. Detailed Implementation

[0042] To better understand this application, various aspects of this application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely illustrative of exemplary embodiments of this application and are not intended to limit the scope of this application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0043] 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.

[0044] 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 strictly to scale.

[0045] In this article, 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 of each lens closest to the subject is called the object-side surface of the lens, and the surface of each lens closest to the imaging plane is called the image-side surface of the lens.

[0046] It should also be understood that the terms "comprising," "including," "having," "containing," and / or "comprising," when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. Furthermore, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features, not individual elements in the list. Additionally, when describing embodiments of this application, the word "may" is used to mean "one or more embodiments of this application." And the term "exemplary" is intended to refer to an example or illustration.

[0047] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms (e.g., those defined in common dictionaries) shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formal sense unless expressly so specified herein.

[0048] It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other. The following embodiments only illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the technical solutions claimed in this application. It should be pointed out that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of this application, and these all fall within the protection scope of this application. For example, the lens group, lens barrel, and spacer element in the various embodiments of this application can be arbitrarily combined, and it is not limited to the lens group in one embodiment being combined only with the lens barrel, spacer element, etc. of that embodiment. The features, principles, and other aspects of this application will be described in detail below with reference to the accompanying drawings and embodiments.

[0049] An imaging system according to an exemplary embodiment of this application may include six lenses with optical power, a lens barrel, and spacers. The six lenses with optical power are a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. At least four spacers are included: a second spacer partially contacting the image side of the second lens, a third spacer partially contacting the image side of the third lens, a fourth spacer partially contacting the image side of the fourth lens, and a fifth spacer partially contacting the image side of the fifth lens. The six lenses are arranged sequentially along the optical axis from the object side to the image side and installed within the lens barrel, and the spacers are also installed within the lens barrel. At least one of the second to fifth spacers has an object-side inner diameter that is not equal to its image-side inner diameter and / or an object-side outer diameter that is not equal to its image-side outer diameter. The difference between the image-side outer diameter and the object-side outer diameter of the lens barrel is greater than 3.5 mm. At least four of the second to fifth spacers are included between the first to sixth lenses, and any two adjacent lenses among the first to sixth lenses may have an air gap.

[0050] In an exemplary embodiment, both the second and fifth lenses can have negative optical power; the fourth lens has positive optical power; and the radius of curvature of the image side surface of the fifth lens is greater than zero. By controlling the optical power and surface shape of the imaging system, the characteristics of an ultra-thin imaging system, a large aperture, and a small head can be ensured.

[0051] In an exemplary embodiment, the imaging system according to this application satisfies: 3.5 < (R3 + R10) / (D5m - D2m) < 16.0, where D5m is the outer diameter of the image-side surface of the fifth spacer element, D2m is the outer diameter of the image-side surface of the second spacer element, R10 is the radius of curvature of the image-side surface of the fifth lens, and R3 is the radius of curvature of the object-side surface of the second lens. By controlling the difference between the outer diameters of the image-side surfaces of the fifth and second lenses within a reasonable range, it helps to reduce the outer diameters of the first four lenses, ensuring a smaller head size of the lens barrel, thereby making the opening size of the mobile phone screen smaller, increasing the screen ratio, and simultaneously reducing the influence of stray light; by reasonably setting the sum of the radius of curvature of the image-side surface of the fifth lens and the radius of curvature of the object-side surface of the second lens, the curvature of the two lenses is effectively controlled, changing the refraction of light, which is beneficial to increasing the amount of light entering the lens and ensuring the relative illumination of the lens; through the above comprehensive control, the structural requirements can be met with a smaller head size. More specifically, the ratio of the sum of R10 and R3 to the difference between D5m and D2m further satisfies: 4.0 < (R3 + R10) / (D5m - D2m) < 15.5.

[0052] In an exemplary embodiment, the imaging system according to this application satisfies: f1 / f3>0 and R5 / R6>0. f1 is the effective focal length of the first lens, f3 is the effective focal length of the third lens, R5 is the radius of curvature of the object-side surface of the third lens, and R6 is the radius of curvature of the image-side surface of the third lens. Through reasonable design of the optical power and surface shape of the first and third lenses, the third lens can achieve better overall uniformity, facilitate lens forming, and share common support with the front and rear lenses, resulting in better overall assembly stability and significantly improving yield. More specifically, the ratio of f1 to f3 can further satisfy: 1.0>f1 / f3>0; the ratio of R5 to R6 can further satisfy: 1.0>R5 / R6>0.

[0053] In an exemplary embodiment, the spacing element of the imaging system according to this application further includes a first spacing element that contacts the image-side portion of the first lens. By adding a spacing element between different lenses, the risk of stray light can be reduced to a certain extent, and the lenses can be better supported, thus increasing lens stability.

[0054] In an exemplary embodiment, the imaging system according to this application satisfies: R7 / R9 < 0, where R7 is the radius of curvature of the object-side surface of the fourth lens, and R9 is the radius of curvature of the object-side surface of the fifth lens. The radius of curvature R7 of the object-side surface of the fourth lens and R9 of the object-side surface of the fifth lens have opposite signs. By reasonably setting the convex and concave surfaces of the fourth and fifth lenses, the curvature of the fourth and fifth lenses can be controlled, thereby reducing the step difference of the bearing surface and improving the stability of lens assembly. More specifically, the ratio of R7 to R9 can further satisfy: R7 / R9 < -0.5.

[0055] In an exemplary embodiment, the imaging system according to this application satisfies: 4.0 < (d5m - D2s + d4m) / (CT2 + CT4 + CT5) < 8.5, where d5m is the inner diameter of the image side of the fifth spacer element, D2s is the outer diameter of the object side of the second spacer element, d4m is the inner diameter of the image side of the fourth spacer element, CT2 is the center thickness of the second lens, CT4 is the center thickness of the fourth lens, and CT5 is the center thickness of the fifth lens. By reasonably setting the difference between the inner diameter of the image side of the fifth lens (d5m) and the outer diameter of the object side of the second lens (D2s) and the sum of the inner diameter of the image side of the fourth spacer element (d4m), it is beneficial to reduce the excess light generated at the edge of the effective area of ​​the lens; by controlling the sum of the center thicknesses of the second, fourth, and fifth lenses, the overall length of the lens can be effectively controlled, further achieving miniaturization. More specifically, the ratio of the sum of the difference between d5m and D2s and d4m to the sum of CT2, CT4, and CT5 further satisfies: 4.5 < (d5m - D2s + d4m) / (CT2 + CT4 + CT5) < 8.0.

[0056] In an exemplary embodiment, the imaging system according to the present application may satisfy: 15.0<d2m / T23+d3m / T34<19.5, where d2m is the inner diameter of the image side surface of the second spacer element, T23 is the air gap between the second lens and the third lens on the optical axis, d3m is the inner diameter of the image side surface of the third spacer element, and T34 is the air gap between the third lens and the fourth lens on the optical axis. By controlling the sum of the ratio of the inner diameter d2m of the image side surface of the second spacer element to the air gap T23 between the second lens and the third lens on the optical axis and the ratio of the inner diameter d3m of the image side surface of the third spacer element to the air gap T34 between the third lens and the fourth lens on the optical axis within a reasonable range, it can ensure blocking part of light, reducing stray light, simultaneously guaranteeing optical parameters such as RI, stabilizing the air gap, reducing lens sensitivity, and improving reliability. More specifically, the sum of the ratio of d2m to T23 and the ratio of d3m to T34 can further satisfy: 15.0<d2m / T23+d3m / T34<19.0.

[0057] In an exemplary embodiment, the imaging system according to the present application satisfies: 15.5<(f4-f5) / (CP5+CP4)<35.5, where f4 is the effective focal length of the fourth lens, f5 is the effective focal length of the fifth lens, CP5 is the maximum thickness of the fifth spacer element, and CP4 is the maximum thickness of the fourth spacer element. By controlling the difference between the effective focal lengths of the fourth lens and the fifth lens, an ideal aperture value can be obtained; controlling the sum of the maximum thicknesses of the fourth spacer element and the fifth spacer element ensures the strength of the lenses, improves assembly stability, and also takes stray light into account, so that stray light reaches an optimal state. More specifically, the ratio of the difference between f4 and f5 to the sum of CP5 and CP4 further satisfies: 16.0<(f4-f5) / (CP5+CP4)<35.0.

[0058] In an exemplary embodiment, the imaging system according to the present application satisfies: -41.0mm 2 <(TD+L)*(f5+CP5)<-33.5mm 2 , wherein TD is the distance from the object side surface of the first lens to the image side surface of the sixth lens on the optical axis, L is the maximum height of the lens barrel, f5 is the effective focal length of the fifth lens, and CP5 is the maximum thickness of the fifth spacer element. By controlling the product of the sum of the distance from the object side surface of the first lens to the image side surface of the sixth lens on the optical axis and the maximum height L of the lens barrel and the sum of the effective focal length f5 of the fifth lens and the maximum thickness CP5 of the fifth spacer element, it can achieve uniform wall thickness of the entire lens barrel, stable molding, good coaxiality and concentricity of each lens stop, and meanwhile the spacer element can effectively block light and improve imaging quality. More specifically, the product of the sum of TD and L and the sum of f5 and CP5 can further satisfy: -41.0mm 2 <(TD+L)*(f5+CP5)<-34.0mm2 .

[0059] In an exemplary embodiment, the imaging system according to the present application satisfies: 16.5<(d4s+d2s) / (T45+T23)<23.5, wherein d4s is the inner diameter of the object side surface of the fourth spacer element, d2s is the inner diameter of the object side surface of the second spacer element, T23 is the air gap between the second lens and the third lens on the optical axis, and T45 is the air gap between the fourth lens and the fifth lens on the optical axis. By reasonably setting the ratio of the sum of the inner diameters of the object side surfaces of the fourth spacer element and the second spacer element to the sum of the air gap between the second lens and the third lens on the optical axis and the air gap between the fourth lens and the fifth lens on the optical axis within a certain range, the strength of the corresponding lenses is increased, so that the lenses can bear against each other, the assembly stability of the system is ensured, which is beneficial to improving the production and assembly yield of the imaging lens. More specifically, the ratio of the sum of d4s and d2s to the sum of T45 and T23 can further satisfy: 17.0<(d4s+d2s) / (T45+T23)<23.0.

[0060] In an exemplary embodiment, the imaging system according to the present application satisfies: -4.0<R9 / R8+d4s / (CP4*10)<16.5, wherein R9 is the curvature radius of the object side surface of the fifth lens, R8 is the curvature radius of the image side surface of the fourth lens, d4s is the inner diameter of the object side surface of the fourth spacer element, and CP4 is the maximum thickness of the fourth spacer element. By reasonably setting the sum of the ratio of the curvature radius R9 of the object side surface of the fifth lens to the curvature radius of the image side surface of the fourth lens and the ratio of the inner diameter d4s of the object side surface of the fourth spacer element to the maximum thickness CP4 thereof, the wall thickness uniformity of the corresponding lenses can be better, the molding risk and appearance risk can be reduced, the step difference can be minimized, and the assembly strength between lenses can be ensured. The reasonable arrangement of the inner diameter d4s of the object side surface of the fourth spacer element and the thickness thereof can balance stray light and main optical parameters. More specifically, the ratio of R9 to R8 and the ratio of d4s to CP4 can further satisfy: -3.5<R9 / R8+d4s / (CP4*10)<16.5.

[0061] In an exemplary embodiment, the imaging system according to the present application satisfies: 17.0<(D5s+d5s) / (CT5+T56)<21.0, where D5s is the object-side outer diameter of the fifth spacer, d5s is the object-side inner diameter of the fifth spacer, CT5 is the central thickness of the fifth lens, and T56 is the air gap between the fifth lens and the sixth lens on the optical axis. By controlling the ratio of the sum of the object-side outer diameter D5s and the object-side inner diameter d5s of the fifth spacer to the sum of the central thickness CT5 of the fifth lens and the air gap between the fifth lens and the sixth lens on the optical axis, it is conducive to better fitting and bearing between the fifth spacer and the fifth lens, making assembly more convenient. The reasonable setting of the inner diameter of the spacer can effectively absorb excess light, ensuring the optimization of stray light and main optical parameters such as RI. Further, the ratio of the sum of D5s and d5s to the sum of CT5 and T56 can satisfy: 17.5<(D5s+d5s) / (CT5+T56)<20.5.

[0062] In an exemplary embodiment, the imaging system according to the present application satisfies: 7.5<EP25 / EP34+TD / CT4<11.5, where EP25 is the spacing between the second spacer and the fifth spacer, EP34 is the spacing between the third spacer and the fourth spacer, TD is the distance from the object-side surface of the first lens to the image-side surface of the sixth lens on the optical axis, and CT4 is the central thickness of the fourth lens. By controlling the ratio of the spacing EP25 between the second spacer and the fifth spacer to the spacing EP34 between the third spacer and the fourth spacer, and controlling the sum of this ratio and the ratio of the distance TD from the object-side surface of the first lens to the image-side surface of the sixth lens on the optical axis to the central thickness CT4 of the fourth lens, the spacing between the spacers can be adjusted and the axial length of the lens group can be controlled, which is conducive to shortening the axial length of the lens barrel, making it more compact and suitable for front-facing camera of lenses. More specifically, the sum of the ratio of EP25 to EP34 and the ratio of TD to CT4 can further satisfy: 7.5<EP25 / EP34+TD / CT4<11.2.

[0063] In an exemplary embodiment, the imaging system according to this application satisfies: -14.0 < (D5m + D4m) / (R7 + R10) < -5.5, where D5m is the outer diameter of the image-side surface of the fifth spacer element, D4m is the outer diameter of the image-side surface of the fourth spacer element, R7 is the radius of curvature of the object-side surface of the fourth lens, and R10 is the radius of curvature of the image-side surface of the fifth lens. By controlling the ratio of the sum of the outer diameters of the image-side surfaces of the fourth and fifth spacers to the sum of the radii of curvature of the object-side surfaces of the fourth and fifth lenses, the shapes of the fourth and fifth lenses can be effectively controlled. By changing the path of light through refraction, an ideal aperture number can be obtained. The setting of the outer diameter of the spacer element controls the size of the rear end face of the lens barrel to a certain extent, avoiding large step differences. More specifically, the ratio of the sum of D5m and D4m to the sum of R7 and R10 can further satisfy: -14.0 < (D5m + D4m) / (R7 + R10) < -6.0.

[0064] In an exemplary embodiment, the imaging system according to this application satisfies: 23.5 < (∑CT - CPmax) / CPave * FNO < 59.0, where ∑CT is the sum of the center thicknesses of all lenses from the first to the sixth lens, CPmax is the maximum value among the maximum thicknesses of all spacers, and CPave is the average value among the maximum thicknesses of all spacers. By controlling the ratio of the difference between the sum of the center thicknesses of all lenses from the first to the sixth lens ∑CT and the maximum value among the maximum thicknesses of all spacers CPmax to the average value among the maximum thicknesses of all spacers CPave, and the product of this ratio and the aperture number FNO of the imaging system, it is beneficial to constrain the aperture number of the lens within a certain range. At the same time, it can effectively control the distribution of spacers and lenses inside the lens. A reasonable distribution of spacers and lenses can effectively reduce the system sensitivity, allowing the lens to maintain good performance even in adverse environments. More specifically, the difference between ∑CT and CPmax, the ratio of CPave, and the product of CPave and FNO can further satisfy: 24.0 < (∑CT - CPmax) / CPave * FNO < 59.0.

[0065] In an exemplary embodiment, the imaging system according to this application satisfies: 2.5 < (D0s + D0m) / f * tan(Semi-FOV) < 4.5, where D0s is the outer diameter of the lens barrel on the object side, D0m is the outer diameter of the lens barrel on the image side, f is the effective focal length of the imaging lens, and Semi-FOV is half of the maximum field of view of the imaging lens. By controlling the ratio of the sum of the outer diameters of the lens barrel on the object side (D0s) and the lens barrel on the image side (D0m) to the effective focal length f of the imaging lens, and by controlling the product of this ratio and the tangent of Semi-FOV (half of the maximum field of view of the imaging lens), the outer diameters at both ends of the lens barrel are reasonably set, ensuring a small front-end size, which is suitable for front-facing applications. Furthermore, the reasonable setting of the effective focal length and field of view helps the lens achieve a large aperture. More specifically, the ratio of the sum of D0s and D0m to f and its product with tan(Semi-FOV) satisfy: 3.0 < (D0s + D0m) / f * tan(Semi-FOV) < 4.0.

[0066] In an exemplary embodiment, the imaging system according to this application satisfies: 2.4 < (CT2 + CT4) / (CP2 + CP4) < 18.0, where CP4 is the maximum thickness of the fourth spacer element, CP2 is the maximum thickness of the second spacer element, CT2 is the center thickness of the second lens, and CT4 is the center thickness of the fourth lens. Setting the maximum thickness of the spacer element within a reasonable range facilitates the processing and shaping of the spacer element; furthermore, comprehensive control of the thickness of the lens and spacer element allows for a more rational internal spatial distribution within the lens and improves image quality. More specifically, the ratio of the sum of CT2 and CT4 to the sum of CP4 and CP2 further satisfies: 2.8 < (CT2 + CT4) / (CP2 + CP4) < 18.0.

[0067] In an exemplary embodiment, the imaging system according to this application satisfies: 3.5 < |(CT3+CT5) / (EP45-EP23)| < 11.5, where CT3 is the center thickness of the third lens, CT5 is the center thickness of the fifth lens, EP45 is the spacing between the fourth and fifth spacers, and EP23 is the spacing between the second and third spacers. By controlling the sum of the center thicknesses of the third and fifth lenses in the imaging system and the difference between the spacing of the fourth and fifth spacers and the spacing of the second and third spacers, ensuring that their ratio is within a certain range is beneficial to the stability of the air gap within the lens and plays an important role in improving product yield. More specifically, the ratio of the sum of CT3 and CT5 to the difference between EP45 and EP23 can further satisfy: 4.0 < |(CT3+CT5) / (EP45-EP23)| < 11.0.

[0068] In an exemplary embodiment, the first to sixth lenses of the imaging system according to this application are all made of plastic. Plastic is advantageous for manufacturing and molding, reducing the difficulty of lens processing and molding. Plastic lenses are less prone to scratches during assembly, which can improve assembly yield, ensure a better material refractive index, and reduce lens manufacturing costs.

[0069] In an exemplary embodiment, the effective focal length f of the optical imaging system can be, for example, in the range of 3.0 mm to 3.5 mm, the effective focal length f1 of the first lens can be, for example, in the range of 3.5 mm to 4.5 mm, the effective focal length f2 of the second lens can be, for example, in the range of -16 mm to -8 mm, the effective focal length f3 of the third lens can be, for example, in the range of 9 mm to 18 mm, the effective focal length f4 of the fourth lens can be, for example, in the range of 2.5 mm to 7 mm, the effective focal length f5 of the fifth lens can be, for example, in the range of -7 mm to -4 mm, and the effective focal length f6 of the sixth lens can be, for example, in the range of -25 mm to 35 mm.

[0070] In an exemplary embodiment, the total length TTL of the imaging system (i.e., the distance from the object side S1 of the first lens E1 to the imaging surface S15 of the imaging system on the optical axis) can be, for example, in the range of 4.3 mm to 4.5 mm, half of the maximum field of view (Semi-FOV) of the imaging system can be, for example, in the range of 40° to 48°, and the aperture number (FNO) of the imaging lens can be, for example, in the range of 1.7 to 2.0.

[0071] In an exemplary embodiment, the imaging system according to this application further includes an aperture stop, which may be disposed between the object side and the first lens. Optionally, the imaging system may also include a filter for correcting color deviation and / or a protective glass for protecting the photosensitive element located on the imaging surface.

[0072] This application proposes an imaging system solution that, while maintaining a relatively large aperture, achieves a smaller overall lens length and head size. The imaging system according to the above-described embodiment of this application can employ multiple lenses, such as the six lenses described above. By rationally allocating the optical power and surface shape of each lens, the center thickness of each lens, and the on-axis spacing between each lens, incident light can be effectively converged, the overall optical length of the imaging lens can be reduced, and the manufacturability of the imaging lens can be improved, making the imaging system more conducive to manufacturing.

[0073] In embodiments of this application, at least one of the mirror surfaces of each lens is an aspherical mirror surface; that is, at least one mirror surface from the object-side surface of the first lens to the image-side surface of the sixth lens is an aspherical mirror surface. The characteristic of an aspherical lens is that its curvature changes continuously from the lens center to the lens periphery. Unlike a spherical lens, which has a constant curvature from the lens center to the lens periphery, an aspherical lens has better curvature radius characteristics, offering advantages in improving distortion aberrations and astigmatism. By using an aspherical lens, aberrations occurring during imaging can be eliminated as much as possible, thereby improving image quality. Optionally, at least one of the object-side and image-side surfaces of each of the first, second, third, fourth, fifth, and sixth lenses is an aspherical mirror surface. Optionally, both the object-side and image-side surfaces of each of the first, second, third, fourth, fifth, and sixth lenses are aspherical mirror surfaces.

[0074] However, those skilled in the art will understand that the number of lenses constituting the imaging 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 six lenses are described as an example in the embodiments, the imaging system is not limited to including six lenses. If desired, the imaging system may also include other numbers of lenses.

[0075] Specific embodiments of the imaging system applicable to the above-described embodiments are further described below with reference to the accompanying drawings.

[0076] Example 1

[0077] The following is for reference Figures 1 to 4D An imaging system according to Embodiment 1 of this application is described. Figure 1 Show to Figure 3 Schematic diagrams of the structures of three imaging systems according to Embodiment 1 of this application are shown respectively.

[0078] like Figures 1 to 3 As shown, imaging systems 110, 120, and 130 may each include a lens group, which, along the optical axis from the object side to the image side, sequentially includes: an aperture stop STO, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, and a sixth lens E6. Optionally, imaging systems 110, 120, and 130 may also include a filter and an imaging surface (not shown).

[0079] The first lens E1 has positive optical power, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has negative optical power, with its object-side surface S3 being convex and its image-side surface S4 being concave. The third lens E3 has positive optical power, with its object-side surface S5 being convex and its image-side surface S6 being concave. The fourth lens E4 has positive optical power, with its object-side surface S7 being concave and its image-side surface S8 being convex. The fifth lens E5 has negative optical power, with its object-side surface S9 being convex and its image-side surface S10 being concave. The sixth lens E6 has positive optical power, with its object-side surface S11 being convex and its image-side surface S12 being concave. The filter has an object-side surface and an image-side surface. Light from the object passes sequentially through each surface S1 to the image-side surface of the filter and is finally imaged on the imaging plane.

[0080] Table 1 shows the basic parameters of the imaging systems 110, 120, and 130 of Embodiment 1, where the units for radius of curvature, thickness / distance, and focal length are millimeters (mm).

[0081]

[0082] Table 1

[0083] In this example, the total effective focal length f of imaging systems 110, 120, and 130 is 3.31 mm, the semi-FOV (half of the maximum field of view) of imaging systems 110, 120, and 130 is 44.25°, the aperture number FNO of imaging systems 110, 120, and 130 is 1.80, and the total length TTL of imaging systems 110, 120, and 130 is 4.35 mm.

[0084] In Embodiment 1, the object-side surface and image-side surface of any one of the first lens E1 to the sixth lens E6 are aspherical surfaces, and the surface shape x of each aspherical lens can be defined using, but is not limited to, the following aspherical formula:

[0085]

[0086] Where x is the distance vector from the vertex of the aspherical surface at a height of 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. Tables 2-1 and 2-2 below give the higher-order coefficients A4, A6, A8, A14, A15, A16, A17, A18, A19 ... 10 A 12 A 14 A 16 A 18 A 20 A 22 A 24 A26 A 28 and A 30 .

[0087] S1 -6.04E-03 -1.31E-03 -7.06E-04 -1.62E-04 -7.00E-05 -1.40E-05 -1.71E-05 S2 -5.85E-02 -7.89E-04 -2.20E-03 -2.91E-05 4.17E-05 -5.63E-05 -4.87E-05 S3 -4.57E-02 8.84E-03 -3.26E-03 6.37E-04 -4.22E-05 -8.71E-05 -7.34E-05 S4 -1.62E-02 9.71E-03 -1.97E-03 1.38E-03 2.64E-04 4.98E-05 -2.27E-05 S5 -1.54E-01 -1.14E-02 6.78E-04 3.69E-03 1.79E-03 6.25E-04 -8.12E-05 S6 -1.74E-01 -5.05E-03 1.27E-02 9.35E-03 3.64E-03 1.16E-03 -2.42E-05 S7 -1.02E-02 1.22E-02 9.14E-03 -1.29E-03 -1.83E-03 2.52E-04 1.74E-04 S8 4.27E-01 4.19E-02 2.83E-02 -2.46E-02 5.60E-03 4.34E-04 1.31E-03 S9 -5.88E-01 -1.36E-01 1.25E-01 -2.06E-02 2.68E-03 -7.40E-03 2.08E-03 S10 -1.52E+00 1.84E-01 4.68E-02 -3.49E-02 -2.92E-03 8.66E-03 -2.56E-03 S11 -4.90E+00 1.48E+00 -5.51E-01 1.91E-01 -4.84E-02 5.56E-04 2.82E-03 S12 -6.08E+00 1.35E+00 -3.97E-01 1.81E-01 -6.04E-02 8.88E-03 -1.37E-02

[0088] Table 2-1

[0089] S1 8.00E-06 -2.87E-06 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S2 -2.08E-05 7.63E-06 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S3 -6.21E-06 -1.29E-06 1.07E-05 -4.10E-06 3.48E-06 -3.48E-06 0.00E+00 S4 -1.51E-05 -1.88E-05 -2.32E-07 -7.71E-07 3.93E-07 0.00E+00 0.00E+00 S5 -1.22E-04 -1.07E-04 -1.38E-05 -7.17E-07 1.49E-05 -2.84E-06 0.00E+00 S6 -1.18E-04 -1.43E-04 -4.89E-05 -3.40E-05 -4.24E-06 0.00E+00 0.00E+00 S7 2.55E-04 -3.25E-05 -5.86E-05 -6.60E-05 -1.63E-06 8.99E-07 5.51E-06 S8 -6.77E-04 -2.75E-05 5.87E-05 1.92E-05 -6.30E-06 3.16E-06 2.21E-06 S9 1.23E-03 5.54E-04 -4.65E-04 -2.01E-04 -4.83E-06 7.84E-05 -1.52E-05 S10 3.03E-03 -3.07E-03 1.14E-03 -7.55E-04 4.55E-04 -2.57E-04 1.04E-04 S11 1.49E-03 -5.13E-03 5.07E-03 -2.40E-03 3.51E-04 3.05E-04 -4.95E-04 S12 6.70E-03 -5.79E-03 2.20E-03 -1.19E-03 3.37E-05 2.81E-04 3.37E-04

[0090] Table 2-2

[0091] Continue to refer to Figures 1 to 3 As shown, imaging systems 110, 120, and 130 may further include multiple spacer elements and a lens barrel for accommodating the aforementioned optical lens groups and multiple spacer elements. The difference between the image-side outer diameter and the object-side outer diameter of the lens barrel is greater than 3.5 mm. The multiple spacer elements include, for example, a first spacer element P1 located between the first lens E1 and the second lens E2, a second spacer element P2 located between the second lens E2 and the third lens E3, a third spacer element P3 located between the third lens E3 and the fourth lens E4, a fourth spacer element P4 located between the fourth lens E4 and the fifth lens E5, and a fifth spacer element P5 located between the fifth lens E5 and the sixth lens E6. By rationally setting the spacer elements, the overall strength and stability of the lens can be enhanced, and the molding process of individual lenses can be improved. Structurally, the fifth spacer element P5 can be set as a thick spacer ring or a lens with a thicker edge can be used to achieve a large step difference between the fifth lens E5 and the sixth lens E6, resulting in better system stability.

[0092] Figure 4A The on-axis chromatic aberration curves of the imaging systems 110, 120, and 130 of Embodiment 1 are shown, which represent the deviation of the focal point of light of different wavelengths after passing through the lens. Figure 4B Astigmatism curves of imaging systems 110, 120, and 130 of Embodiment 1 are shown, representing meridional and sagittal plane curvature. Figure 4C The distortion curves of the imaging systems 110, 120 and 130 of Embodiment 1 are shown, which represent the distortion magnitude values ​​corresponding to different fields of view. Figure 4D The magnification chromatic aberration curves of the imaging systems 110, 120, and 130 of Embodiment 1 are shown, representing the deviation of light at different image heights on the imaging plane after passing through the lens. According to Figures 4A to 4D It can be seen that the imaging systems 110, 120 and 130 given in Example 1 can achieve good imaging quality.

[0093] Example 2

[0094] The following is for reference Figures 5 to 8D An imaging system according to Embodiment 2 of this application is described. Figures 5 to 7Schematic diagrams of the structures of three imaging systems according to Embodiment 2 of this application are shown respectively.

[0095] like Figures 5 to 7 As shown, imaging systems 210, 220, and 230 may each include a lens group, which, along the optical axis from the object side to the image side, sequentially includes: an aperture stop STO, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, and a sixth lens E6. Optionally, imaging systems 210, 220, and 230 may also include a filter and an imaging surface (not shown).

[0096] The first lens E1 has positive optical power, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has negative optical power, with its object-side surface S3 being convex and its image-side surface S4 being concave. The third lens E3 has positive optical power, with its object-side surface S5 being convex and its image-side surface S6 being concave. The fourth lens E4 has positive optical power, with its object-side surface S7 being concave and its image-side surface S8 being convex. The fifth lens E5 has negative optical power, with its object-side surface S9 being convex and its image-side surface S10 being concave. The sixth lens E6 has negative optical power, with its object-side surface S11 being convex and its image-side surface S12 being concave. The filter has an object-side surface and an image-side surface. Light from the object passes sequentially through each surface S1 to the image-side surface of the filter and is finally imaged on the imaging plane.

[0097] In this example, the total effective focal length f of imaging systems 210, 220 and 230 is 3.08 mm, the semi-FOV (half of the maximum field of view) of imaging systems 210, 220 and 230 is 47.43°, the aperture number FNO of imaging systems 210, 220 and 230 is 1.80, and the total length TTL of imaging systems 210, 220 and 230 is 4.35 mm.

[0098] Table 3 shows the basic parameters of imaging systems 210, 220, and 230 of Embodiment 2, wherein the units of radius of curvature, thickness / distance, and focal length are millimeters (mm). Tables 4-1 and 4-2 show the higher-order coefficients that can be used for each aspherical mirror in Embodiment 2, wherein each aspherical surface shape can be defined by formula (1) given in Embodiment 1 above.

[0099]

[0100] Table 3

[0101] S1 -4.00E-03 -1.68E-03 -8.30E-04 -2.54E-04 -8.95E-05 -2.46E-05 -1.63E-05 S2 -7.01E-02 -1.88E-03 -3.29E-03 -3.49E-04 1.81E-04 5.52E-05 -7.47E-06 S3 -4.19E-02 9.60E-03 -3.43E-03 5.18E-04 2.49E-04 -2.31E-05 -7.62E-05 S4 -8.34E-03 9.10E-03 -2.28E-03 1.23E-03 3.31E-04 4.36E-05 9.51E-08 S5 -1.65E-01 -1.32E-02 -7.10E-06 3.16E-03 1.69E-03 5.61E-04 -5.28E-05 S6 -1.72E-01 -1.19E-03 1.05E-02 6.72E-03 2.50E-03 8.94E-04 1.29E-04 S7 -8.75E-02 2.06E-02 9.54E-03 -5.11E-05 -2.19E-03 2.17E-04 -1.73E-05 S8 2.86E-01 6.35E-03 3.08E-02 -3.23E-02 4.40E-03 8.66E-04 2.79E-03 S9 -6.75E-01 -1.56E-01 1.45E-01 -2.58E-02 2.68E-03 -8.04E-03 3.11E-03 S10 -1.68E+00 1.98E-01 6.50E-02 -5.18E-02 4.45E-03 6.80E-03 -1.61E-03 S11 -5.44E+00 1.63E+00 -6.03E-01 2.19E-01 -6.01E-02 3.86E-03 3.37E-03 S12 -7.18E+00 1.73E+00 -5.43E-01 2.31E-01 -8.63E-02 2.07E-02 -1.37E-02

[0102] Table 4-1

[0103]

[0104]

[0105] Table 4-2

[0106] Continue to refer to Figures 5 to 7 As shown, imaging systems 210, 220, and 230 may further include multiple spacer elements and a lens barrel for accommodating the aforementioned optical lens groups and multiple spacer elements. The difference between the image-side outer diameter and the object-side outer diameter of the lens barrel is greater than 3.5 mm. The multiple spacer elements include, for example, a first spacer element P1 located between the first lens E1 and the second lens E2, a second spacer element P2 located between the second lens E2 and the third lens E3, a third spacer element P3 located between the third lens E3 and the fourth lens E4, a fourth spacer element P4 located between the fourth lens E4 and the fifth lens E5, and a fifth spacer element P5 located between the fifth lens E5 and the sixth lens E6. By rationally setting the spacer elements, the overall strength and stability of the lens can be enhanced, and the molding process of individual lenses can be improved. Structurally, the fifth spacer element P5 can be set as a thick spacer ring or a lens extension method can be used to achieve a large step difference between the fifth lens E5 and the sixth lens E6, resulting in better system stability.

[0107] Figure 8A The on-axis chromatic aberration curves of the imaging systems 210, 220, and 230 of Embodiment 2 are shown, which represent the deviation of the focal point of light of different wavelengths after passing through the lens. Figure 8B Astigmatism curves of imaging systems 210, 220, and 230 of Embodiment 2 are shown, representing meridional and sagittal plane curvature. Figure 8C The distortion curves of imaging systems 210, 220, and 230 of Embodiment 2 are shown, representing the distortion magnitude values ​​corresponding to different fields of view. Figure 8D The magnification chromatic aberration curves of imaging systems 210, 220, and 230 of Embodiment 2 are shown, representing the deviation of light at different image heights on the imaging plane after passing through the lens. According to Figures 8A to 8D It can be seen that the imaging systems 210, 220 and 230 given in Example 2 can achieve good imaging quality.

[0108] Example 3

[0109] The following is for reference Figures 9 to 12D An imaging system according to Embodiment 3 of this application is described. Figures 9 to 11 Schematic diagrams of the structures of three imaging systems according to Embodiment 3 of this application are shown respectively.

[0110] like Figures 9 to 11As shown, imaging systems 310, 320, and 330 may include a lens group, which, along the optical axis from the object side to the image side, sequentially includes: an aperture stop STO, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, and a sixth lens E6. Optionally, imaging systems 310, 320, and 330 may also include a filter and an imaging surface (not shown).

[0111] The first lens E1 has positive optical power, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has negative optical power, with its object-side surface S3 being concave and its image-side surface S4 being concave. The third lens E3 has positive optical power, with its object-side surface S5 being concave and its image-side surface S6 being concave. The fourth lens E4 has positive optical power, with its object-side surface S7 being concave and its image-side surface S8 being convex. The fifth lens E5 has negative optical power, with its object-side surface S9 being concave and its image-side surface S10 being convex. The sixth lens E6 has negative optical power, with its object-side surface S11 being concave and its image-side surface S12 being convex. The filter has an object-side surface and an image-side surface. Light from the object passes sequentially through each surface S1 to the image-side surface of the filter and is finally imaged on the imaging plane.

[0112] In this example, the total effective focal length f of imaging systems 310, 320 and 330 is 3.27 mm, the semi-FOV (half of the maximum field of view) of imaging systems 310, 320 and 330 is 42.73°, the aperture number FNO of imaging systems is 1.86, and the total length TTL of imaging systems 310, 320 and 330 is 4.35 mm.

[0113] Table 5 shows the basic parameters of imaging systems 310, 320, and 330 in Embodiment 3, where the units for radius of curvature, thickness / distance, and focal length are millimeters (mm). Tables 6-1 and 6-2 show the higher-order coefficients that can be used for each aspherical mirror in Embodiment 3, where each aspherical surface shape can be defined by formula (1) given in Embodiment 1 above.

[0114]

[0115] Table 5

[0116]

[0117]

[0118] Table 6-1

[0119] S1 1.00E-05 -5.09E-06 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S2 -2.23E-05 -1.31E-06 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S3 -3.89E-06 2.17E-06 1.38E-05 -1.85E-06 1.44E-06 -4.54E-06 0.00E+00 S4 -3.89E-06 2.17E-06 1.38E-05 -1.85E-06 1.44E-06 -4.54E-06 0.00E+00 S5 -2.24E-04 -1.47E-04 -3.65E-05 3.14E-06 1.20E-05 1.35E-06 0.00E+00 S6 -1.25E-04 -1.24E-04 -7.57E-05 -3.54E-05 -1.65E-05 0.00E+00 0.00E+00 S7 2.56E-04 -1.68E-04 -2.15E-04 -9.49E-05 3.06E-06 2.62E-05 5.13E-06 S8 -1.57E-03 3.73E-05 -2.28E-05 -1.94E-04 -8.36E-05 1.05E-04 1.97E-05 S9 1.41E-03 -1.29E-03 -1.10E-03 -1.42E-04 2.83E-04 1.35E-04 -4.18E-05 S10 -3.68E-05 -2.71E-03 1.60E-03 -8.62E-04 4.04E-04 -3.04E-04 1.70E-04 S11 3.99E-03 -6.72E-03 4.68E-03 -1.96E-03 1.01E-04 3.13E-04 -1.88E-04 S12 1.14E-02 -5.85E-03 2.64E-03 -1.66E-03 -1.00E-05 -2.77E-04 4.42E-04

[0120] Table 6-2

[0121] Continue to refer to Figures 9 to 11As shown, imaging systems 310, 320, and 330 may further include multiple spacer elements and a lens barrel for accommodating the aforementioned optical lens groups and multiple spacer elements. The difference between the image-side outer diameter and the object-side outer diameter of the lens barrel is greater than 3.5 mm. The multiple spacer elements include, for example, a first spacer element P1 located between the first lens E1 and the second lens E2, a second spacer element P2 located between the second lens E2 and the third lens E3, a third spacer element P3 located between the third lens E3 and the fourth lens E4, a fourth spacer element P4 located between the fourth lens E4 and the fifth lens E5, and a fifth spacer element P5 located between the fifth lens E5 and the sixth lens E6. By rationally setting the spacer elements, the overall strength and stability of the lens can be enhanced, and the molding process of individual lenses can be improved. Structurally, the fifth spacer element P5 can be set as a thick spacer ring or a lens extension method can be used to achieve a large step difference between the fifth lens E5 and the sixth lens E6, resulting in better system stability.

[0122] Figure 12A The on-axis chromatic aberration curves of the imaging systems 310, 320, and 330 of Embodiment 3 are shown, which represent the deviation of the focal point of light of different wavelengths after passing through the lens. Figure 12B Astigmatism curves of imaging systems 310, 320, and 330 of Embodiment 3 are shown, representing meridional and sagittal plane curvature. Figure 12C The distortion curves of the imaging systems 310, 320 and 330 of Embodiment 3 are shown, which represent the distortion magnitude corresponding to different fields of view. Figure 12D The magnification chromatic aberration curves of imaging systems 310, 320, and 330 of Embodiment 3 are shown, representing the deviation of light at different image heights on the imaging plane after passing through the lens. According to Figures 12A to 12D It can be seen that the imaging systems 310, 320 and 330 given in Example 3 can achieve good imaging quality.

[0123] Figure 13 The diagrams provided are schematic representations of the imaging systems according to Embodiments 1 to 3 of this application. The dimensions of each part of the imaging system provided in Embodiments 1 to 3 of this application can be referenced. Figure 13 As shown in Table 7, the specific dimensional parameters of the imaging systems in each embodiment satisfy the relationships shown in Table 8.

[0124]

[0125] Table 7

[0126]

[0127]

[0128] Table 8

[0129] 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 imaging system described above.

[0130] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. An imaging system, characterized in that, include: A lens group includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged sequentially along the optical axis from the object side to the image side. The radius of curvature of the image side of the fifth lens is greater than zero. The first lens, the third lens, and the fourth lens all have positive optical power, and the second lens and the fifth lens all have negative optical power. The number of lenses with optical power in the lens group is six. Multiple spacer elements, including: The second spacer element is in contact with the image-side portion of the second lens. The fourth spacer element is in contact with the image-side portion of the fourth lens. The fifth spacer element is in contact with the image-side surface of the fifth lens. Wherein, at least one of the plurality of spacer elements has an inner diameter on the object side that is not equal to the inner diameter on the image side and / or an outer diameter on the object side that is not equal to the outer diameter on the image side; and The lens barrel houses the lens group and the plurality of spacer elements, and the difference between the outer diameter of the image side and the outer diameter of the object side of the lens barrel is greater than 3.5 mm. The imaging system satisfies: -13.52≤(D5m+D4m) / (R7+R10)≤-6.33 and 17.55≤(d4s+d2s) / (T45+T23)≤22.97, Wherein, D5m is the outer diameter of the image-side surface of the fifth spacer element, D4m is the outer diameter of the image-side surface of the fourth spacer element, R7 is the radius of curvature of the object-side surface of the fourth lens, R10 is the radius of curvature of the image-side surface of the fifth lens, d4s is the inner diameter of the object-side surface of the fourth spacer element, d2s is the inner diameter of the object-side surface of the second spacer element, T23 is the air gap between the second lens and the third lens on the optical axis, and T45 is the air gap between the fourth lens and the fifth lens on the optical axis.

2. The imaging system according to claim 1, characterized in that, The imaging system satisfies: 0.30≤R5 / R6≤0.45 Wherein, R5 is the radius of curvature of the object side of the third lens, and R6 is the radius of curvature of the image side of the third lens.

3. The imaging system according to claim 1, characterized in that, The plurality of spacer elements also include: The first spacer element is in contact with the image-side portion of the first lens.

4. The imaging system according to claim 1, characterized in that, The imaging system satisfies: -0.84≤R7 / R9≤-0.55, Wherein, R9 is the radius of curvature of the object-side surface of the fifth lens.

5. The imaging system according to claim 1, characterized in that, The imaging system satisfies: 4.55≤(d5m-D2s+d4m) / (CT2+CT4+CT5)≤7.61, Wherein, d5m is the inner diameter of the image side of the fifth spacer element, D2s is the outer diameter of the object side of the second spacer element, d4m is the inner diameter of the image side of the fourth spacer element, CT2 is the center thickness of the second lens, CT4 is the center thickness of the fourth lens, and CT5 is the center thickness of the fifth lens.

6. The imaging system according to claim 1, characterized in that, The plurality of spacer elements further includes: a third spacer element, which contacts the image-side portion of the third lens, wherein the imaging system satisfies: 15.58≤d2m / T23+d3m / T34≤18.87, Wherein, d2m is the inner diameter of the image side of the second spacer element, d3m is the inner diameter of the image side of the third spacer element, and T34 is the air gap between the third lens and the fourth lens on the optical axis.

7. The imaging system according to claim 1, characterized in that, The imaging system satisfies: 16.61≤(f4-f5) / (CP5+CP4)≤34.58, Wherein, f4 is the effective focal length of the fourth lens, f5 is the effective focal length of the fifth lens, CP5 is the maximum thickness of the fifth spacer element, and CP4 is the maximum thickness of the fourth spacer element.

8. The imaging system according to claim 1, characterized in that, The imaging system satisfies: -40.10mm 2 ≤(TD+L) (f5+CP5)≤-34.35mm 2 , Wherein, TD is the distance from the object side of the first lens to the image side of the sixth lens on the optical axis, L is the maximum dimension of the lens barrel along the optical axis, f5 is the effective focal length of the fifth lens, and CP5 is the maximum thickness of the fifth spacer element.

9. The imaging system according to claim 1, characterized in that, The imaging system satisfies: -3.40≤R9 / R8+d4s / (CP4 10)≤16.16, Wherein, R9 is the radius of curvature of the object side of the fifth lens, R8 is the radius of curvature of the image side of the fourth lens, and CP4 is the maximum thickness of the fourth spacer element.

10. The imaging system according to claim 1, characterized in that, The imaging system satisfies: 17.57≤(D5s+d5s) / (CT5+T56)≤20.28, Wherein, D5s is the outer diameter of the object side of the fifth spacer element, d5s is the inner diameter of the object side of the fifth spacer element, CT5 is the center thickness of the fifth lens, and T56 is the air gap between the fifth lens and the sixth lens on the optical axis.

11. The imaging system according to claim 1, characterized in that, The plurality of spacer elements further includes: a third spacer element, which contacts the image-side portion of the third lens, wherein the imaging system satisfies: 8.00≤EP25 / EP34+TD / CT4≤11.15, Wherein, EP25 is the spacing between the second spacer element and the fifth spacer element, EP34 is the spacing between the third spacer element and the fourth spacer element, TD is the distance from the object side of the first lens to the image side of the sixth lens on the optical axis, and CT4 is the center thickness of the fourth lens.

12. The imaging system according to claim 3, characterized in that, The plurality of spacer elements further includes: a third spacer element, which contacts the image-side portion of the third lens, wherein the imaging system satisfies: 24.47≤(∑CT-CPmax) / CPave FNO≤58.44, Wherein, ∑CT is the sum of the center thicknesses of all lenses from the first lens to the sixth lens, CPmax is the maximum value among the maximum thicknesses of all spacers, CPave is the average value of the maximum thicknesses of all spacers, and FNO is the aperture number of the imaging system.

13. The imaging system according to claim 1, characterized in that, The imaging system satisfies: 3.02≤(D0s+D0m) / f tan(Semi-FOV)≤3 Wherein, D0s is the outer diameter of the object side of the lens barrel, D0m is the outer diameter of the image side of the lens barrel, f is the effective focal length of the imaging system, and Semi-FOV is half of the maximum field of view of the imaging system.

14. The imaging system according to claim 1, characterized in that, The imaging system satisfies: 2.90≤(CT2+CT4) / (CP2+CP4)≤17.50, Wherein, CP4 is the maximum thickness of the fourth spacer element, CP2 is the maximum thickness of the second spacer element, CT2 is the center thickness of the second lens, and CT4 is the center thickness of the fourth lens.

15. The imaging system according to claim 1, characterized in that, The plurality of spacer elements further includes: a third spacer element, which contacts the image-side portion of the third lens, wherein the imaging system satisfies: 4.38≤|(CT3+CT5) / (EP45-EP23)|≤10.67, Wherein, CT3 is the center thickness of the third lens, CT5 is the center thickness of the fifth lens, EP45 is the spacing between the fourth and fifth spacers, and EP23 is the spacing between the second and third spacers.

16. The imaging system according to any one of claims 1 to 15, characterized in that, The first lens through the sixth lens are all made of plastic.

17. An imaging system, characterized in that, include: A lens group includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged sequentially along the optical axis from the object side to the image side. The second lens and the fifth lens both have negative optical power, the first lens, the third lens, and the fourth lens all have positive optical power, and the radius of curvature of the image side of the fifth lens is greater than zero. The number of lenses with optical power in the lens group is six. Multiple spacer elements, including: The second spacer element is in contact with the image-side portion of the second lens. The fourth spacer element is in contact with the image-side portion of the fourth lens. The fifth spacer element is in contact with the image-side surface of the fifth lens. Wherein, at least one of the plurality of spacer elements has an object-side inner diameter that is not equal to an image-side inner diameter and / or an object-side outer diameter that is not equal to an image-side outer diameter; and The lens barrel houses the lens group and the plurality of spacer elements, and the difference between the outer diameter of the image side and the outer diameter of the object side of the lens barrel is greater than 3.5 mm. The imaging system satisfies: 16.61≤(f4-f5) / (CP5+CP4)≤34.58 and 17.55≤(d4s+d2s) / (T45+T23)≤22.97, Wherein, f4 is the effective focal length of the fourth lens, f5 is the effective focal length of the fifth lens, CP5 is the maximum thickness of the fifth spacer element, CP4 is the maximum thickness of the fourth spacer element, d4s is the inner diameter of the object side of the fourth spacer element, d2s is the inner diameter of the object side of the second spacer element, T23 is the air gap between the second lens and the third lens on the optical axis, and T45 is the air gap between the fourth lens and the fifth lens on the optical axis.

18. The imaging system according to claim 17, characterized in that, The imaging system satisfies: 0.30≤R5 / R6≤0.45 Wherein, R5 is the radius of curvature of the object side of the third lens, and R6 is the radius of curvature of the image side of the third lens.

19. The imaging system according to claim 17, characterized in that, The plurality of spacer elements also include: The first spacer element is in contact with the image-side portion of the first lens.

20. The imaging system according to claim 17, characterized in that, The imaging system satisfies: -0.84≤R7 / R9≤-0.55, Wherein, R7 is the radius of curvature of the object-side surface of the fourth lens, and R9 is the radius of curvature of the object-side surface of the fifth lens.

21. The imaging system according to claim 17, characterized in that, The imaging system satisfies: 4.55≤(d5m-D2s+d4m) / (CT2+CT4+CT5)≤7.61, Wherein, d5m is the inner diameter of the image side of the fifth spacer element, D2s is the outer diameter of the object side of the second spacer element, d4m is the inner diameter of the image side of the fourth spacer element, CT2 is the center thickness of the second lens, CT4 is the center thickness of the fourth lens, and CT5 is the center thickness of the fifth lens.

22. The imaging system according to claim 17, characterized in that, The plurality of spacer elements further includes: a third spacer element, which contacts the image-side portion of the third lens, wherein the imaging system satisfies: 15.58≤d2m / T23+d3m / T34≤18.87, Wherein, d2m is the inner diameter of the image side of the second spacer element, d3m is the inner diameter of the image side of the third spacer element, and T34 is the air gap between the third lens and the fourth lens on the optical axis.

23. The imaging system according to claim 17, characterized in that, The imaging system satisfies: -40.10mm 2 ≤(TD+L) (f5+CP5)≤-34.35mm 2 , Wherein, TD is the distance from the object side of the first lens to the image side of the sixth lens on the optical axis, and L is the maximum dimension of the lens barrel along the optical axis.

24. The imaging system according to claim 17, characterized in that, The imaging system satisfies: -3.40≤R9 / R8+d4s / (CP4 10)≤16.16, Wherein, R9 is the radius of curvature of the object side of the fifth lens, R8 is the radius of curvature of the image side of the fourth lens, and CP4 is the maximum thickness of the fourth spacer element.

25. The imaging system according to claim 17, characterized in that, The imaging system satisfies: 17.57≤(D5s+d5s) / (CT5+T56)≤20.28, Wherein, D5s is the outer diameter of the object side of the fifth spacer element, d5s is the inner diameter of the object side of the fifth spacer element, CT5 is the center thickness of the fifth lens, and T56 is the air gap between the fifth lens and the sixth lens on the optical axis.

26. The imaging system according to claim 17, characterized in that, The plurality of spacer elements further includes: a third spacer element, which contacts the image-side portion of the third lens, wherein the imaging system satisfies: 8.00≤EP25 / EP34+TD / CT4≤11.15, Wherein, EP25 is the spacing between the second spacer element and the fifth spacer element, EP34 is the spacing between the third spacer element and the fourth spacer element, TD is the distance from the object side of the first lens to the image side of the sixth lens on the optical axis, and CT4 is the center thickness of the fourth lens.

27. The imaging system according to claim 19, characterized in that, The plurality of spacer elements further includes: a third spacer element, which contacts the image-side portion of the third lens, wherein the imaging system satisfies: 24.47≤(∑CT-CPmax) / CPave FNO≤58.44, Wherein, ∑CT is the sum of the center thicknesses of all lenses from the first lens to the sixth lens, CPmax is the maximum value among the maximum thicknesses of all spacers, CPave is the average value of the maximum thicknesses of all spacers, and FNO is the aperture number of the imaging system.

28. The imaging system according to claim 17, characterized in that, The imaging system satisfies: 3.02≤(D0s+D0m) / f tan(Semi-FOV)≤3 Wherein, D0s is the outer diameter of the object side of the lens barrel, D0m is the outer diameter of the image side of the lens barrel, f is the effective focal length of the imaging system, and Semi-FOV is half of the maximum field of view of the imaging system.

29. The imaging system according to claim 17, characterized in that, The imaging system satisfies: 2.90≤(CT2+CT4) / (CP2+CP4)≤17.50, Wherein, CP2 is the maximum thickness of the second spacer element, CT2 is the center thickness of the second lens, and CT4 is the center thickness of the fourth lens.

30. The imaging system according to claim 17, characterized in that, The plurality of spacer elements further includes: a third spacer element, which contacts the image-side portion of the third lens, wherein the imaging system satisfies: 4.38≤|(CT3+CT5) / (EP45-EP23)|≤10.67, Wherein, CT3 is the center thickness of the third lens, CT5 is the center thickness of the fifth lens, EP45 is the spacing between the fourth and fifth spacers, and EP23 is the spacing between the second and third spacers.

31. The imaging system according to any one of claims 17 to 30, characterized in that, The first lens through the sixth lens are all made of plastic.

32. The imaging system according to claim 31, characterized in that, The imaging system satisfies: -13.52≤(D5m+D4m) / (R7+R10)≤-6.33, Wherein, D5m is the outer diameter of the image side of the fifth spacer element, D4m is the outer diameter of the image side of the fourth spacer element, R7 is the radius of curvature of the object side of the fourth lens, and R10 is the radius of curvature of the image side of the fifth lens.

Images