Optical imaging system

Abstract

The application discloses an optical imaging system, which comprises, in order from the object side to the image side along the optical axis, a first lens with negative focal power, a second lens with positive focal power, a third lens with positive focal power, a fourth lens with positive focal power, a fifth lens with negative focal power, a sixth lens with negative focal power, a seventh lens with positive focal power, and an eighth lens with negative focal power. The Abbe number of at least four lenses among the first lens to the eighth lens is less than 30; there is an air gap between any two adjacent lenses among the first lens to the eighth lens; at least one mirror surface among the object side surface of the first lens to the image side surface of the eighth lens is a non-spherical mirror surface; and the optical imaging system satisfies: 4.0 < CT2 / CT1+TAN(Semi-FOV) < 5.0, wherein Semi-FOV is half of the maximum field angle of the optical imaging system, CT1 is the central thickness of the first lens on the optical axis, and CT2 is the central thickness of the second lens on the optical axis.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical elements, and in particular, to an optical imaging system. BACKGROUND

[0002] With the continuous improvement of the technical capabilities of portable electronic devices such as smart phones, the trend of using mobile phone cameras instead of traditional cameras is becoming more and more obvious. In order to improve the competitiveness of their products, major smart phone manufacturers have put forward higher design requirements for optical imaging systems mounted on smart phones.

[0003] Wide-angle imaging systems are easy to give the photographer a sense of distance due to their large field of view and long depth of field, which helps to enhance the appeal of the picture and gives the photographer a sense of being there. Large-format imaging systems are favored by photographers due to their high resolution. Therefore, most optical imaging systems are developing towards large format, wide angle, and high imaging quality.

[0004] However, the structure of traditional five-piece, six-piece or even seven-piece lenses is not enough to effectively cope with the above challenges. Therefore, how to reasonably set the number, optical power, technical parameters, etc. of each lens in the optical imaging system so that the optical imaging system can meet market demand has become one of the difficult problems to be solved by many lens designers. SUMMARY

[0005] In one aspect, the present application provides an optical imaging system including, in order from an object side to an image side along an optical axis, a first lens having a negative optical power, a second lens having a positive optical power, a third lens having a positive optical power, a fourth lens having a positive optical power, a fifth lens having a negative optical power, a sixth lens having a negative optical power, a seventh lens having a positive optical power, and an eighth lens having a negative optical power. An Abbe number of at least four lenses among the first lens to the eighth lens is less than 30; there is an air gap between any two adjacent lenses among the first lens to the eighth lens; at least one of the mirror surfaces from the object side surface of the first lens to the image side surface of the eighth lens is a non-spherical mirror surface; and the optical imaging system satisfies 4.0 < CT2 / CT1+TAN(Semi-FOV) < 5.0, where Semi-FOV is half of the maximum field of view angle of the optical imaging system, CT1 is the center thickness of the first lens on the optical axis, and CT2 is the center thickness of the second lens on the optical axis.

[0006] In one embodiment, the optical imaging system satisfies -4.0 < f2 / f1+R2 / R1 < -3.5, where f1 is the effective focal length of the first lens, f2 is the effective focal length of the second lens, R1 is the curvature radius of the object side surface of the first lens, and R2 is the curvature radius of the image side surface of the first lens.

[0007] In one embodiment, the optical imaging system can satisfy: -4.0 < (R5-R6) / (R5+R6) < -2.5, where 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.

[0008] In one embodiment, the optical imaging system can satisfy: 9.5 < f3 / CT3 + |R6| / f3 < 10.5, where f3 is the effective focal length of the third lens, R6 is the radius of curvature of the image side surface of the third lens, and CT3 is the center thickness of the third lens on the optical axis.

[0009] In one embodiment, the optical imaging system can satisfy: 0.5 < (f4+f5) / (R8+R9) < 1.5, where f4 is the effective focal length of the fourth lens, f5 is the effective focal length of the fifth lens, R8 is the radius of curvature of the image side surface of the fourth lens, and R9 is the radius of curvature of the object side surface of the fifth lens.

[0010] In one embodiment, the optical imaging system can satisfy: 6.5 < f5 / R10 + CT5 / T45 < 7.5, where f5 is the effective focal length of the fifth lens, R10 is the radius of curvature of the image side surface of the fifth lens, CT5 is the center thickness of the fifth lens on the optical axis, and T45 is the air separation of the fourth lens and the fifth lens on the optical axis.

[0011] In one embodiment, the optical imaging system can satisfy: 2.0 < T56 / CT6 + |f6| / R12 < 3.5, where T56 is the air separation of the fifth lens and the sixth lens on the optical axis, CT6 is the center thickness of the sixth lens on the optical axis, f6 is the effective focal length of the sixth lens, and R12 is the radius of curvature of the image side surface of the sixth lens.

[0012] In one embodiment, the optical imaging system can satisfy: -9.0 < f7 / R13 + f8 / R15 < -1.0, where f7 is the effective focal length of the seventh lens, f8 is the effective focal length of the eighth lens, R13 is the radius of curvature of the object side surface of the seventh lens, and R15 is the radius of curvature of the object side surface of the eighth lens.

[0013] In one embodiment, the optical imaging system can satisfy: 1.5 < (SAG61+SAG62) / (SAG61-SAG62) < 4.5, where SAG61 is the distance from the intersection of the object side surface of the sixth lens and the optical axis to the effective radius vertex of the object side surface of the sixth lens on the optical axis, and SAG62 is the distance from the intersection of the image side surface of the sixth lens and the optical axis to the effective radius vertex of the image side surface of the sixth lens on the optical axis.

[0014] In one embodiment, the optical imaging system can satisfy: 1.0 < (SAG72+SAG81) / SAG82 < 3.0, where SAG72 is the distance from the intersection of the image side surface of the seventh lens and the optical axis to the effective radius vertex on the optical axis of the image side surface of the seventh lens, SAG81 is the distance from the intersection of the object side surface of the eighth lens and the optical axis to the effective radius vertex on the optical axis of the object side surface of the eighth lens, and SAG82 is the distance from the intersection of the image side surface of the eighth lens and the optical axis to the effective radius vertex on the optical axis of the image side surface of the eighth lens.

[0015] In one embodiment, the optical imaging system can satisfy: -4.5 < f56 / (CT5+CT6) < -2.0, where f56 is the combined focal length of the fifth lens and the sixth lens, CT5 is the center thickness of the fifth lens on the optical axis, and CT6 is the center thickness of the sixth lens on the optical axis.

[0016] In one embodiment, the optical imaging system can satisfy: 0.5 < f67 / (R12+R13) < 2.0, where f67 is the combined focal length of the sixth lens and the seventh lens, R12 is the radius of curvature of the image side surface of the sixth lens, and R13 is the radius of curvature of the object side surface of the seventh lens.

[0017] In one embodiment, the optical imaging system can satisfy: 3.0 < f78 / R16+CT7 / CT8 < 4.5, where f78 is the combined focal length of the seventh lens and the eighth lens, R16 is the radius of curvature of the image side surface of the eighth lens, CT7 is the center thickness of the seventh lens on the optical axis, and CT8 is the center thickness of the eighth lens on the optical axis.

[0018] In one embodiment, the optical imaging system can satisfy: V8 < 25, where V8 is the Abbe number of the eighth lens.

[0019] In the exemplary embodiments of the present application, by reasonably setting the optical power, asphericity, Abbe number of each lens, and the spacing between the lenses, and by matching 4.0 < CT2 / CT1+TAN(Semi-FOV) < 5.0, the optical imaging system has the characteristics of large image surface, ultra-wide angle, etc. For example, in a large image surface imaging system, by reasonably setting the optical power of each lens, the low-order aberrations of the system can be effectively balanced, so that the system has good imaging quality and processability; by controlling the Abbe number of the lens, the system chromatic aberration and performance can be balanced, and the imaging quality can be improved; by controlling the center thickness ratio of the first lens and the second lens and the field of view, the processability of the lens can be improved, the field of view of the system can be improved, and the light can be better converged, and the image quality of the system can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0020] Other features, objects, and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments thereof as taken in conjunction with the accompanying drawings:

[0021] Figure 1 A structural schematic diagram of an optical imaging system according to Embodiment 1 of the present application is shown;

[0022] Figure 2A and Figure 2B Axial chromatic aberration curves and astigmatism curves of the optical imaging system of Embodiment 1 are shown, respectively;

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

[0024] Figure 4A and Figure 4B Axial chromatic aberration curves and astigmatism curves of the optical imaging system of Embodiment 2 are shown, respectively;

[0025] Figure 5 A structural schematic diagram of an optical imaging system according to Embodiment 3 of the present application is shown;

[0026] Figure 6A and Figure 6B Axial chromatic aberration curves and astigmatism curves of the optical imaging system of Embodiment 3 are shown, respectively;

[0027] Figure 7 A structural schematic diagram of an optical imaging system according to Embodiment 4 of the present application is shown;

[0028] Figure 8A and Figure 8B Axial chromatic aberration curves and astigmatism curves of the optical imaging system of Embodiment 4 are shown, respectively;

[0029] Figure 9 A structural schematic diagram of an optical imaging system according to Embodiment 5 of the present application is shown; and

[0030] Figure 10A and Figure 10B Axial chromatic aberration curves and astigmatism curves of the optical imaging system of Embodiment 5 are shown, respectively. DETAILED DESCRIPTION

[0031] For a better understanding of the present application, various aspects of the present application will be described in greater detail below with reference to the accompanying drawings. It is to be understood that the detailed description is merely descriptive of exemplary embodiments of the present application and that no limitations are thereby intended to the scope of the present application. Throughout the specification, like reference numerals refer to like elements. The expression “and / or” includes any and all combinations of one or more of the associated listed items.

[0032] It should be noted that the terms first, second, third, etc. are used herein only to distinguish one feature from another, and do not denote any limitation. Thus, a first lens discussed below can also be termed a second lens or a third lens, without departing from the teachings of the present application.

[0033] In the drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of explanation. Specifically, the shape of the spherical or aspherical surface shown in the drawings is shown by way of example. That is, the shape of the spherical or aspherical surface is not limited to the shape of the spherical or aspherical surface shown in the drawings. The drawings are merely examples and are not drawn to scale.

[0034] Herein, the paraxial region refers to a region near the optical axis. If a lens surface is convex and the position of the convex surface is not specified, it means that the lens surface is convex at least in the paraxial region. If a lens surface is concave and the position of the concave surface is not specified, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is referred to as the object side surface of the lens, and the surface of each lens closest to the image plane is referred to as the image side surface of the lens.

[0035] It should also be understood that the words "comprise", "comprising", "include", "including", and / or "contain", when used in this specification, specify the presence of stated features, elements, and / or components, but do not preclude the presence or addition of one or more other features, elements, components, and / or groups thereof. Furthermore, when describing the embodiments of the present application, the use of "may" indicates that one or more embodiments of the present application. Also, the word "exemplary" is intended to mean an example or an illustration.

[0036] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an overly idealized or overly formal sense unless expressly so defined herein.

[0037] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0038] The features, principles, and other aspects of the present application are described in detail below.

[0039] An optical imaging system according to an example embodiment of the present application can include eight lenses with optical power, which are a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens, respectively. The eight lenses are arranged in order along an optical axis from an object side to an image side. Any two adjacent lenses among the first lens to the eighth lens can have a separation distance.

[0040] According to an example embodiment of the present application, the first lens can have negative optical power; the second lens can have positive optical power; the third lens can have positive optical power; the fourth lens can have positive optical power; the fifth lens can have negative optical power; the sixth lens can have negative optical power; the seventh lens can have positive optical power; and the eighth lens can have negative optical power.

[0041] In an example embodiment, the Abbe number of at least four lenses among the first lens to the eighth lens can be less than 30. Any two adjacent lenses among the first lens to the eighth lens can have an air separation. The optical imaging system according to the present application can satisfy 4.0 < CT2 / CT1+TAN(Semi-FOV) < 5.0, where Semi-FOV is half of the maximum field angle of the optical imaging system, CT1 is the center thickness of the first lens on the optical axis, and CT2 is the center thickness of the second lens on the optical axis. In the present application, by reasonably setting the optical power, Abbe number, and separation distance of each lens, and by satisfying 4.0 < CT2 / CT1+TAN(Semi-FOV) < 5.0, the optical imaging system has the characteristics of a large image surface and an ultra-wide angle, for example. In a large image surface imaging system, by reasonably setting the optical power of each lens, the low-order aberration of the system can be effectively balanced, so that the system has good imaging quality and processability; by controlling the Abbe number of the lens, the chromatic aberration and performance of the system can be balanced, and the imaging quality can be improved; by controlling the center thickness ratio of the first lens and the second lens and the field angle, the processability of the lens can be improved, the field angle of the system can be improved, and the light can be better converged, and the image quality of the system can be improved.

[0042] In an example embodiment, the optical imaging system according to the present application can satisfy -4.0 < f2 / f1+R2 / R1 < -3.5, where f1 is the effective focal length of the first lens, f2 is the effective focal length of the second lens, R1 is the radius of curvature of the object side surface of the first lens, and R2 is the radius of curvature of the image side surface of the first lens. Satisfying -4.0 < f2 / f1+R2 / R1 < -3.5 is beneficial to reasonably distribute the optical power of the first lens and the second lens, and is beneficial to control the deflection angle of the edge field light on the object side surface and the image side surface of the first lens within a reasonable range, and is further beneficial to effectively reduce the sensitivity of the system.

[0043] In the example embodiment, the optical imaging system according to the present application can satisfy: -4.0 < (R5-R6) / (R5+R6) < -2.5, where 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. Satisfying -4.0 < (R5-R6) / (R5+R6) < -2.5 can effectively reduce the coma of the on-axis field of view and the off-axis field of view of the imaging system by restricting the ratio of the difference and the sum of the radii of curvature of the object side surface and the image side surface of the third lens within a certain range, so that the imaging system has good imaging quality.

[0044] In the example embodiment, the optical imaging system according to the present application can satisfy: 9.5 < f3 / CT3+|R6| / f3 < 10.5, where f3 is the effective focal length of the third lens, R6 is the radius of curvature of the image side surface of the third lens, and CT3 is the central thickness of the third lens on the optical axis. Satisfying 9.5 < f3 / CT3+|R6| / f3 < 10.5 can control the machinability of the third lens and the contribution rate of the spherical aberration of the third lens within a reasonable range, so that the on-axis field of view of the system has good imaging quality.

[0045] In the example embodiment, the optical imaging system according to the present application can satisfy: 0.5 < (f4+f5) / (R8+R9) < 1.5, where f4 is the effective focal length of the fourth lens, f5 is the effective focal length of the fifth lens, R8 is the radius of curvature of the image side surface of the fourth lens, and R9 is the radius of curvature of the object side surface of the fifth lens. Satisfying 0.5 < (f4+f5) / (R8+R9) < 1.5 is conducive to reasonably setting the optical power of the fourth lens and the fifth lens, and the surface shape of the fourth lens and the fifth lens, so that the fourth lens and the fifth lens have better processing and forming process.

[0046] In the example embodiment, the optical imaging system according to the present application can satisfy: 6.5 < f5 / R10+CT5 / T45 < 7.5, where f5 is the effective focal length of the fifth lens, R10 is the radius of curvature of the image side surface of the fifth lens, CT5 is the central thickness of the fifth lens on the optical axis, and T45 is the air gap of the fourth lens and the fifth lens on the optical axis. Satisfying 6.5 < f5 / R10+CT5 / T45 < 7.5 is conducive to reducing the generation of ghost images between the fourth lens and the fifth lens, and is also conducive to making the optical imaging system have better spherical aberration and distortion correction functions.

[0047] In exemplary embodiments, the optical imaging system according to the present application can satisfy: 2.0 < T56 / CT6 + |f6| / R12 < 3.5, where T56 is the air separation of the fifth lens and the sixth lens on the optical axis, CT6 is the center thickness of the sixth lens on the optical axis, f6 is the effective focal length of the sixth lens, and R12 is the curvature radius of the image side surface of the sixth lens. Satisfying 2.0 < T56 / CT6 + |f6| / R12 < 3.5 can not only reasonably distribute the optical power of the system, control the third-order astigmatism of the system within a certain range, balance the astigmatism generated by the front-end optics and the rear-end optics of the system, so that the system has good imaging quality, but also effectively control the shape of the fifth lens and the sixth lens, control the range of the residual distortion in the system after the distortion generated by the fifth lens and the sixth lens and the distortion generated by other lenses are offset, so that the system has good distortion performance.

[0048] In exemplary embodiments, the optical imaging system according to the present application can satisfy: -9.0 < f7 / R13 + f8 / R15 < -1.0, where f7 is the effective focal length of the seventh lens, f8 is the effective focal length of the eighth lens, R13 is the curvature radius of the object side surface of the seventh lens, and R15 is the curvature radius of the object side surface of the eighth lens. Satisfying -9.0 < f7 / R13 + f8 / R15 < -1.0 is conducive to controlling the imaging quality of the optical imaging system and the assembly tolerance sensitivity of the seventh lens and the eighth lens within a relatively reasonable range.

[0049] In exemplary embodiments, the optical imaging system according to the present application can satisfy: 1.5 < (SAG61 + SAG62) / (SAG61 - SAG62) < 4.5, where SAG61 is the distance on the optical axis from the intersection of the object side surface of the sixth lens and the optical axis to the effective radius vertex of the object side surface of the sixth lens, and SAG62 is the distance on the optical axis from the intersection of the image side surface of the sixth lens and the optical axis to the effective radius vertex of the image side surface of the sixth lens. Satisfying 1.5 < (SAG61 + SAG62) / (SAG61 - SAG62) < 4.5 can adjust the chief ray angle of the optical imaging system by controlling the sag of the object side surface of the sixth lens and the image side surface of the sixth lens within a certain range, effectively improve the relative brightness of the optical imaging system, and improve the image clarity.

[0050] In the exemplary embodiments, the optical imaging system according to the present application can satisfy: 1.0 < (SAG72 + SAG81) / SAG82 < 3.0, where SAG72 is the distance from the intersection of the image side surface of the seventh lens and the optical axis to the effective radius vertex of the image side surface of the seventh lens on the optical axis, SAG81 is the distance from the intersection of the object side surface of the eighth lens and the optical axis to the effective radius vertex of the object side surface of the eighth lens on the optical axis, and SAG82 is the distance from the intersection of the image side surface of the eighth lens and the optical axis to the effective radius vertex of the image side surface of the eighth lens on the optical axis. Satisfying 1.0 < (SAG72 + SAG81) / SAG82 < 3.0 can effectively reduce the sensitivity of the seventh lens and the eighth lens and improve the processing formability of the seventh lens and the eighth lens by controlling the ratio of the sum of the sagittal heights of the image side surface of the seventh lens and the object side surface of the eighth lens to the sagittal height of the image side surface of the eighth lens within a certain range.

[0051] In the exemplary embodiments, the optical imaging system according to the present application can satisfy: -4.5 < f56 / (CT5 + CT6) < -2.0, where f56 is the combined focal length of the fifth lens and the sixth lens, CT5 is the central thickness of the fifth lens on the optical axis, and CT6 is the central thickness of the sixth lens on the optical axis. Satisfying -4.5 < f56 / (CT5 + CT6) < -2.0 can reasonably control the performance of the coma of the system by controlling the ratio of the combined focal length of the fifth lens and the sixth lens to the sum of the central thicknesses of the fifth lens and the sixth lens on the axis within a certain range, so that the optical imaging system has good optical performance.

[0052] In the exemplary embodiments, the optical imaging system according to the present application can satisfy: 0.5 < f67 / (R12 + R13) < 2.0, where f67 is the combined focal length of the sixth lens and the seventh lens, R12 is the curvature radius of the image side surface of the sixth lens, and R13 is the curvature radius of the object side surface of the seventh lens. Satisfying 0.5 < f67 / (R12 + R13) < 2.0 is conducive to better correcting the chromatic aberration of the system and improving the imaging quality, and is also conducive to reducing the increase in the system tolerance sensitivity caused by excessive concentration of the focal power of the lens and excessive bending of the lens surface.

[0053] In the exemplary embodiments, the optical imaging system according to the present application can satisfy: 3.0 < f78 / R16 + CT7 / CT8 < 4.5, where f78 is the combined focal length of the seventh lens and the eighth lens, R16 is the curvature radius of the image side surface of the eighth lens, CT7 is the central thickness of the seventh lens on the optical axis, and CT8 is the central thickness of the eighth lens on the optical axis. Satisfying 3.0 < f78 / R16 + CT7 / CT8 < 4.5 is conducive to adjusting the focal power distribution and shortening the total length of the system, and thus is conducive to realizing the characteristics of small size and low tolerance sensitivity of the system.

[0054] In the example embodiments, the optical imaging system according to the present application can satisfy: V8<25, where V8 is the Abbe number of the eighth lens. Satisfying V8<25 is conducive to reducing the system chromatic aberration, improving the system optical performance, and thus improving the imaging quality, by reasonably setting the Abbe number of the eighth lens.

[0055] In the example embodiments, the optical imaging system according to the present application further includes a diaphragm arranged between the second lens and the third lens. Optionally, the optical imaging system described above can further include a filter for correcting color deviation and / or a protective glass for protecting the photosensitive element located on the imaging surface. The present application proposes an optical imaging system with the characteristics of miniaturization, large image surface, wide angle, and high imaging quality. The optical imaging system according to the above-described embodiments of the present application can employ multiple lenses, for example, eight lenses as described above. By reasonably allocating the optical power, surface type, material, central thickness of each lens, and axial distance between each lens, etc., the incident light can be effectively converged, the total optical length of the imaging lens can be reduced, and the processability of the imaging lens can be improved, so that the optical imaging system is more conducive to production and processing.

[0056] In the embodiments of the present application, at least one of the lens surfaces of each lens is an aspherical lens surface, that is, at least one of the object side surface of the first lens to the image side surface of the eighth lens is an aspherical lens surface. The aspherical lens has the characteristic that the curvature continuously changes from the center of the lens to the periphery of the lens. Unlike the spherical lens having a constant curvature from the center of the lens to the periphery of the lens, the aspherical lens has better curvature radius characteristics, has the advantages of improving the distortion aberration and improving the astigmatism aberration. After using the aspherical lens, the aberration that occurs during imaging can be eliminated as much as possible, thereby improving the imaging quality. Optionally, at least one of the object side surface and the image side surface of each of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens is an aspherical lens surface. Optionally, the object side surface and the image side surface of each of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, and the eighth lens are aspherical lens surfaces.

[0057] However, those skilled in the art should understand that the number of lenses constituting the optical imaging system can be changed without departing from the technical solutions claimed by the present application, to obtain the various results and advantages described in the present specification. For example, although eight lenses are described as an example in the embodiments, the optical imaging system is not limited to including eight lenses. If necessary, the optical imaging system can further include other numbers of lenses.

[0058] The specific embodiments of the optical imaging system applicable to the above-described embodiments are further described below with reference to the accompanying drawings.

[0059] Example 1

[0060] The optical imaging system according to Embodiment 1 of the present application is described below with reference to the accompanying drawings. Figures 1-2B An optical imaging system according to Embodiment 1 of the present application is shown. Figure 1 An optical imaging system according to Embodiment 1 of the present application is shown.

[0061] As shown in FIG. 1, the optical imaging system sequentially includes, from the object side to the image side: a first lens E1, a second lens E2, a stop STO, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, an eighth lens E8, a filter E9, and an imaging surface S19. Figure 1 The first lens E1 has a negative focal power, the object side surface S1 is a concave surface, and the image side surface S2 is a concave surface. The second lens E2 has a positive focal power, the object side surface S3 is a convex surface, and the image side surface S4 is a concave surface. The third lens E3 has a positive focal power, the object side surface S5 is a convex surface, and the image side surface S6 is a convex surface. The fourth lens E4 has a positive focal power, the object side surface S7 is a concave surface, and the image side surface S8 is a convex surface. The fifth lens E5 has a negative focal power, the object side surface S9 is a concave surface, and the image side surface S10 is a convex surface. The sixth lens E6 has a negative focal power, the object side surface S11 is a concave surface, and the image side surface S12 is a concave surface. The seventh lens E7 has a positive focal power, the object side surface S13 is a convex surface, and the image side surface S14 is a concave surface. The eighth lens E8 has a negative focal power, the object side surface S15 is a convex surface, and the image side surface S16 is a concave surface. The filter E9 has an object side surface S17 and an image side surface S18. Light from the object sequentially passes through the surfaces S1 to S18 and is finally imaged on the imaging surface S19.

[0062] Table 1 shows the basic parameter table of the optical imaging system of Embodiment 1, wherein the units of the radius of curvature, the thickness / distance, and the focal length are all millimeters (mm).

[0063]

[0064] Table 1

[0065] In this example, the total effective focal length f of the optical imaging system is 2.35 mm, the half of the maximum field of view angle Semi-FOV of the optical imaging system is 67.4°, and the aperture value Fno of the optical imaging system is 2.23.

[0066] In Embodiment 1, the object side surface and the image side surface of any one of the first lens E1 to the eighth lens E8 are aspherical surfaces, and the surface type x of each aspherical lens can be defined by, but is not limited to, the following aspherical formula:

[0067]

[0068]

[0069] ​Wherein, x is the distance vector height of the aspheric surface from the vertex of the aspheric surface at a height of h along the optical axis; c is the paraxial curvature of the aspheric surface, c = 1 / R (i.e., the paraxial curvature c is the reciprocal of the curvature radius R in Table 1 above); k is the conic coefficient; Ai is the correction coefficient of the i-th order of the aspheric surface. The following Tables 2-1 and 2-2 give the high-order coefficients A4, A6, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22, A23, A24, A25, A26, A27, A28, A29, A30, A31, A32, A33, A34, A35, A36, A37, A38, A39, A40, A41, A42, A43, A44, A45, A46, A47, A50, A51, A52, A53, A54, A55, A56, A57, A58, A59, A60, A61, A71, A72, A73, A74, A75, A80, A81, A9, A10, A11, A12, A13, A14, A15 10 、A 12 、A 14 、A 16 、A 18 、A 20 、A 22 、A 24 、A 26 、A 28 and A 30 .

[0070]

[0071]

[0072] Table 2-1

[0073] Face Number A18 A20 A22 A24 A26 A28 A30 S1 -2.6413E-03 1.2266E-03 -6.4391E-04 2.7859E-04 -1.5223E-04 4.7777E-05 -2.7693E-05 S2 -1.1223E-04 -1.3887E-04 1.5152E-05 -2.2684E-05 2.5277E-05 -1.4498E-05 4.4372E-06 S3 5.7364E-05 -4.1902E-05 -2.0804E-05 -1.7833E-05 6.5933E-06 -2.6823E-06 6.8878E-06 S4 -6.5434E-06 5.2820E-08 -1.3663E-06 3.7181E-06 4.5967E-07 1.5597E-06 -1.4771E-06 S5 2.6151E-07 8.2455E-07 -4.1137E-07 3.5500E-07 -2.0550E-07 0.0000E+00 0.0000E+00 S6 -7.6850E-05 -2.9258E-05 -7.3261E-06 1.8512E-06 3.5904E-07 0.0000E+00 0.0000E+00 S7 -2.9016E-05 -8.9935E-06 -3.1288E-06 1.2576E-06 8.6685E-07 0.0000E+00 0.0000E+00 S8 3.8475E-05 1.5551E-04 -8.8249E-06 1.2928E-05 -2.4627E-05 -3.7119E-06 -9.0566E-06 S9 -5.8282E-05 1.8379E-04 -1.0490E-05 -1.0276E-05 -3.7078E-05 -1.2447E-05 -8.0479E-07 S10 -3.1286E-02 -7.8880E-03 3.0828E-02 -8.8435E-03 4.7183E-03 -3.7046E-03 4.5330E-04 S11 -1.0743E-03 -5.0631E-04 -1.1941E-03 -3.8187E-04 -2.0076E-04 -2.9916E-05 -9.4373E-06 S12 -2.6228E-03 -4.5186E-05 -3.2532E-04 -3.0621E-04 -7.4530E-04 -1.2856E-04 1.4511E-04 S13 -2.4309E-03 -2.1197E-03 -1.1184E-03 -9.6102E-04 -4.3291E-04 -1.7663E-03 -1.1177E-04 S14 -6.1695E-01 -1.7296E-01 4.0820E-02 -1.8296E-02 6.1398E-02 -3.2873E-02 2.1121E-02 S15 -1.2373E-03 1.4383E-05 -5.7919E-03 4.0272E-03 -2.9057E-03 -7.8609E-04 -7.3833E-05 S16 2.3025E-02 -1.5082E-02 3.7268E-03 1.0682E-03 3.6998E-03 -2.2054E-04 -1.7949E-03

[0074] Table 2-2

[0075] Figure 2A The axial chromatic aberration curve of the optical imaging system of Example 1 is shown, which indicates the deviation of the focal point of light of different wavelengths passing through the lens. Figure 2B The astigmatism curve of the optical imaging system of Example 1 is shown, which represents the meridional field curvature and the sagittal field curvature. Figure 2A and Figure 2B It can be seen that the optical imaging system provided in Example 1 can achieve good imaging quality.

[0076] Example 2

[0077] The following reference Figures 3-4B The optical imaging system according to Example 2 of the present application is described. In this embodiment and the following embodiments, some descriptions similar to Example 1 will be omitted for the sake of brevity. Figure 3 A structural schematic diagram of an optical imaging system according to Example 2 of the present application is shown.

[0078] like Figure 3 As shown, the optical imaging system includes, from the object side to the image side, a first lens E1, a second lens E2, an aperture STO, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, an eighth lens E8, a filter E9 and an imaging surface S19.

[0079] The first lens E1 has negative focal power, with a concave object side surface S1 and a concave image side surface S2. The second lens E2 has positive focal power, with a convex object side surface S3 and a concave image side surface S4. The third lens E3 has positive focal power, with a convex object side surface S5 and a convex image side surface S6. The fourth lens E4 has positive focal power, with a concave object side surface S7 and a convex image side surface S8. The fifth lens E5 has negative focal power, with a concave object side surface S9 and a convex image side surface S10. The sixth lens E6 has negative focal power, with a convex object side surface S11 and a concave image side surface S12. The seventh lens E7 has positive focal power, with a convex object side surface S13 and a convex image side surface S14. The eighth lens E8 has negative focal power, with a convex object side surface S15 and a concave image side surface S16. The filter E9 has an object side surface S17 and an image side surface S18. Light from an object passes through the surfaces S1 to S18 in sequence and is ultimately imaged on an image plane S19.

[0080] In this example, the total effective focal length f of the optical imaging system is 2.37 mm, the half of the maximum field of view angle Semi-FOV of the optical imaging system is 66.3°, and the F number Fno of the optical imaging system is 2.23.

[0081] Table 3 shows a basic parameter table of the optical imaging system of Example 2, where the units of the radius of curvature, thickness / distance, and focal length are all millimeters (mm). Tables 4-1, 4-2 show the high order term coefficients of the aspherical surfaces that can be used in the optical imaging system of Example 2, where each aspherical surface can be defined by the formula (1) given above in Example 1.

[0082]

[0083] Table 3

[0084]

[0085]

[0086] Table 4-1

[0087] Face Number A18 A20 A22 A24 A26 A28 A30 S1 -1.7040E-03 7.7841E-04 -3.5705E-04 1.5868E-04 -6.7183E-05 2.1891E-05 -3.3710E-06 S2 5.0171E-05 -5.1476E-05 4.1258E-06 -1.5588E-05 1.3564E-05 -8.6374E-06 1.7078E-06 S3 6.0148E-05 1.8458E-06 9.9388E-06 -7.9682E-06 4.1027E-06 -5.3609E-06 1.5461E-06 S4 -4.3025E-08 -2.6107E-07 -3.2882E-06 8.0150E-07 -1.0933E-06 1.6142E-06 -4.6788E-07 S5 -1.4566E-06 4.4370E-07 -1.1240E-07 3.4535E-07 -1.2372E-07 0.0000E+00 0.0000E+00 S6 -5.9202E-07 6.1031E-07 -7.6784E-07 4.6366E-08 3.5681E-08 0.0000E+00 0.0000E+00 S7 -2.2741E-06 7.3466E-07 -1.0023E-06 -2.9249E-07 1.3016E-07 0.0000E+00 0.0000E+00 S8 -1.1837E-04 8.5301E-05 -1.4664E-05 1.9966E-05 -6.9462E-06 5.3834E-06 -2.6049E-06 S9 -2.0670E-04 7.8776E-05 -7.6270E-06 2.0796E-05 -2.1304E-06 -2.1728E-06 -1.5628E-07 S10 -3.3436E-04 1.2705E-04 -4.7052E-05 1.1220E-05 1.0026E-06 -6.5061E-08 -3.0860E-07 S11 -8.0342E-04 6.6920E-04 -1.8963E-04 1.3330E-04 -3.1591E-05 1.4784E-05 -9.3126E-06 S12 -1.4756E-03 1.3529E-04 -1.1926E-04 4.0316E-04 -1.5222E-04 2.5447E-05 -1.8250E-05 S13 6.0410E-04 -2.5388E-04 -3.6848E-05 5.2048E-04 4.1872E-04 -1.6851E-04 -2.7005E-05 S14 -8.2067E-03 6.3967E-03 -4.0838E-03 2.5516E-03 3.5508E-04 -4.5916E-04 -3.3642E-04 S15 3.0585E-03 1.4916E-03 -6.4348E-03 6.5201E-03 -4.9277E-03 2.8899E-03 -7.9740E-04 S16 2.7150E-02 -1.0329E-02 2.5106E-03 4.0368E-04 -6.1310E-04 4.8973E-04 -1.5695E-04

[0088] Table 4-2

[0089] Figure 4A The on-axis chromatic aberration curve of the optical imaging system of Example 2 is shown, which represents the convergence point deviation of light rays of different wavelengths after passing through the lens. Figure 4B The astigmatism curve of the optical imaging system of Example 2 is shown, which represents the meridional image surface curvature and sagittal image surface curvature. According to the formula (2) given above in Example 1, the meridional image surface curvature and the sagittal image surface curvature of the optical imaging system of Example 2 are shown in the following table. Figure 4A and Figure 4BIt can be seen that the optical imaging system provided in Example 2 can achieve good imaging quality.

[0090] Example 3

[0091] The following reference Figures 5-6B An optical imaging system according to Example 3 of the present application is described. Figure 5 A structural schematic diagram of an optical imaging system according to Example 3 of the present application is shown.

[0092] like Figure 5 As shown, the optical imaging system includes, from the object side to the image side, a first lens E1, a second lens E2, an aperture STO, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, an eighth lens E8, a filter E9 and an imaging surface S19.

[0093] The first lens E1 has negative optical power, with its object-side surface S1 being concave and its image-side surface S2 being concave. The second lens E2 has positive 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 convex. The fourth lens E4 has positive optical power, with its object-side surface S7 being convex 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 convex and its image-side surface S12 being concave. The seventh lens E7 has positive optical power, with its object-side surface S13 being convex and its image-side surface S14 being convex. The eighth lens E8 has negative optical power, with its object-side surface S15 being convex and its image-side surface S16 being concave. The filter E9 has an object-side surface S17 and an image-side surface S18. Light from the object passes through the surfaces S1 to S18 in sequence and is finally imaged on the imaging surface S19.

[0094] In this example, the total effective focal length f of the optical imaging system is 2.32 mm, half of the maximum field of view Semi-FOV of the optical imaging system is 69.8°, and the aperture value Fno of the optical imaging system is 2.23.

[0095] Table 5 shows the basic parameters of the optical imaging system of Example 3, where the units of curvature radius, thickness / distance, and focal length are all in millimeters (mm). Tables 6-1 and 6-2 show the high-order coefficients of each aspheric mirror surface that can be used in Example 3, where the surface shape of each aspheric surface can be defined by formula (1) given in Example 1 above.

[0096]

[0097] Table 5

[0098]

[0099]

[0100] Table 6-1

[0101] Face Number A18 A20 A22 A24 A26 A28 A30 S1 -1.7008E-03 7.7783E-04 -3.5757E-04 1.5923E-04 -6.7414E-05 2.1258E-05 -3.0886E-06 S2 1.1597E-04 -7.2650E-05 6.8477E-06 -3.6801E-05 1.6852E-05 -8.7679E-06 1.4622E-06 S3 5.1851E-05 1.1471E-06 7.0945E-06 -8.7574E-06 4.9060E-06 -5.3609E-06 1.5461E-06 S4 -6.7622E-06 -1.7585E-06 -3.2882E-06 8.0150E-07 -1.0933E-06 1.6142E-06 -4.6788E-07 S5 -4.6045E-07 6.6649E-07 -6.6232E-07 3.4535E-07 -1.2372E-07 0.0000E+00 0.0000E+00 S6 -9.1087E-07 6.4761E-07 -1.7746E-06 4.6366E-08 3.5681E-08 0.0000E+00 0.0000E+00 S7 -2.2741E-06 7.3466E-07 -1.0023E-06 -2.9249E-07 1.3016E-07 0.0000E+00 0.0000E+00 S8 -9.3911E-05 7.1450E-05 -1.5906E-05 1.9966E-05 -6.9462E-06 5.3834E-06 -2.6049E-06 S9 -1.6977E-04 7.4598E-05 -2.3663E-06 1.9187E-05 -1.0483E-06 -2.1728E-06 -1.5628E-07 S10 -2.7817E-04 1.0001E-04 -3.4718E-05 7.1029E-06 5.2399E-07 3.9316E-07 -3.0860E-07 S11 -4.6281E-04 4.9831E-04 -1.5084E-04 9.6076E-05 -1.5049E-05 8.6784E-06 -7.7253E-06 S12 -1.0675E-03 -1.1742E-04 4.7493E-04 6.4733E-05 -2.2345E-04 9.7133E-05 -2.6538E-05 S13 -1.3400E-05 -1.2269E-04 1.5462E-03 1.1144E-03 -1.1809E-03 -9.8857E-04 -1.4419E-04 S14 -6.7733E-03 6.7404E-03 -3.3260E-03 4.9261E-03 -1.5620E-03 -5.7976E-04 -9.1815E-04 S15 3.7114E-03 1.8128E-03 -6.0710E-03 5.0306E-03 -6.4286E-03 5.5122E-03 -1.6043E-03 S16 2.6010E-02 -1.0207E-02 2.3804E-03 3.1942E-04 -5.5531E-04 5.1061E-04 -1.4529E-04

[0102] Table 6-2

[0103] Figure 6A The axial chromatic aberration curve of the optical imaging system of Example 3 is shown, which indicates the deviation of the focal point of light of different wavelengths after passing through the lens. Figure 6B The astigmatism curve of the optical imaging system of Example 3 is shown, which represents the meridional field curvature and the sagittal field curvature. Figure 6A and Figure 6B It can be seen that the optical imaging system provided in Example 3 can achieve good imaging quality.

[0104] Example 4

[0105] The following reference Figures 7-8B An optical imaging system according to Example 4 of the present application is described. Figure 7 A structural schematic diagram of an optical imaging system according to Example 4 of the present application is shown.

[0106] like Figure 7 As shown, the optical imaging system includes, from the object side to the image side, a first lens E1, a second lens E2, an aperture STO, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, an eighth lens E8, a filter E9 and an imaging surface S19.

[0107] The first lens E1 has negative optical power, with its object-side surface S1 being concave and its image-side surface S2 being concave. The second lens E2 has positive 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 convex. 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 convex and its image-side surface S12 being concave. The seventh lens E7 has positive optical power, with its object-side surface S13 being convex and its image-side surface S14 being concave. The eighth lens E8 has negative optical power, with its object-side surface S15 being convex and its image-side surface S16 being concave. The filter E9 has an object-side surface S17 and an image-side surface S18. Light from the object passes through the surfaces S1 to S18 in sequence and is finally imaged on the imaging surface S19.

[0108] In this example, the total effective focal length f of the optical imaging system is 2.38 mm, half of the maximum field of view Semi-FOV of the optical imaging system is 66.7°, and the aperture value Fno of the optical imaging system is 2.23.

[0109] Table 7 shows the basic parameters of the optical imaging system of Example 4, where the units of curvature radius, thickness / distance, and focal length are all in millimeters (mm). Tables 8-1 and 8-2 show the high-order coefficients of each aspheric mirror surface that can be used in Example 4, where the surface shape of each aspheric surface can be defined by formula (1) given in Example 1 above.

[0110]

[0111]

[0112] Table 7

[0113] Face Number A4 A6 A8 A10 A12 A14 A16 S1 1.5098E+00 -3.2528E-01 1.0446E-01 -4.2047E-02 1.8604E-02 -8.3118E-03 3.7602E-03 S2 4.4991E-01 -6.7420E-02 1.8255E-02 -1.0581E-02 2.4640E-03 4.9638E-04 3.2129E-04 S3 4.4855E-02 1.1603E-02 -5.9622E-04 -2.5431E-03 -2.7401E-04 8.3285E-05 3.6666E-05 S4 8.5950E-02 7.3612E-03 -1.0963E-04 -4.7677E-04 -3.9716E-05 -7.8425E-06 1.6000E-05 S5 1.0224E-02 3.4280E-04 -5.3988E-05 1.4961E-06 -4.2115E-06 1.0099E-06 -8.1399E-07 S6 3.8948E-03 2.1009E-03 9.4965E-05 -2.1781E-05 -5.0651E-06 -2.1180E-06 1.8693E-06 S7 3.2363E-03 -1.5740E-03 -4.5620E-04 3.8548E-05 9.6838E-05 9.0532E-06 2.1842E-05 S8 -1.5026E-01 -5.2894E-03 3.4877E-03 -9.0113E-04 1.5269E-03 -6.0538E-04 2.8130E-04 S9 -2.3405E-01 -1.5704E-02 9.4915E-03 -2.1286E-03 2.7748E-03 -1.1843E-03 2.1047E-04 S10 -2.7917E-02 -2.0625E-02 2.1272E-02 -7.9564E-03 4.2912E-03 -1.8418E-03 7.2470E-04 S11 1.3387E-01 -1.9288E-01 2.9540E-02 -1.7754E-02 6.5508E-03 -4.7375E-03 1.9127E-03 S12 -1.5700E+00 1.0649E-01 -6.3791E-02 2.8733E-02 -1.8412E-02 7.8298E-03 8.3639E-04 S13 -3.3573E+00 4.7482E-01 -7.0182E-02 2.3594E-02 -9.4099E-03 -8.2687E-04 3.7345E-03 S14 -3.7049E-01 -2.7086E-01 5.0295E-02 -6.4294E-02 6.4692E-02 -2.8792E-02 1.4404E-02 S15 -6.5768E+00 1.7013E+00 -6.3701E-01 3.0607E-01 -1.5444E-01 4.0459E-02 -3.0699E-03 S16 -1.0210E+01 2.3681E+00 -8.6073E-01 4.0701E-01 -1.9539E-01 8.5935E-02 -4.8253E-02

[0114] Table 8-1

[0115] Face Number A18 A20 A22 A24 A26 A28 A30 S1 -1.6997E-03 7.8058E-04 -3.5809E-04 1.5866E-04 -6.7519E-05 2.1587E-05 -3.1788E-06 S2 5.2904E-05 -4.6174E-05 -1.1616E-07 -1.9660E-05 1.3616E-05 -8.7066E-06 1.6635E-06 S3 5.8021E-05 1.7474E-06 6.7710E-06 -7.3380E-06 4.1004E-06 -5.3609E-06 1.5461E-06 S4 -5.7053E-06 4.2414E-07 -3.2882E-06 8.0150E-07 -1.0933E-06 1.6142E-06 -4.6788E-07 S5 -6.7003E-07 -8.9165E-08 -5.2387E-08 3.4535E-07 -1.2372E-07 0.0000E+00 0.0000E+00 S6 -1.1211E-06 1.7701E-06 -1.2850E-06 4.6366E-08 3.5681E-08 0.0000E+00 0.0000E+00 S7 -2.2741E-06 7.3466E-07 -1.0023E-06 -2.9249E-07 1.3016E-07 0.0000E+00 0.0000E+00 S8 -1.1359E-04 8.2651E-05 -1.8564E-05 1.9966E-05 -6.9462E-06 5.3834E-06 -2.6049E-06 S9 -1.8885E-04 7.0877E-05 -6.2422E-06 1.7054E-05 -1.4513E-09 -2.1728E-06 -1.5628E-07 S10 -2.9818E-04 1.0950E-04 -4.0049E-05 9.3792E-06 -2.0984E-07 5.0070E-07 -3.0860E-07 S11 -5.7383E-04 5.8593E-04 -1.5977E-04 1.0875E-04 -3.0261E-05 7.5838E-06 -5.4342E-06 S12 -1.7334E-03 4.4438E-05 2.9506E-04 3.1486E-04 -1.7096E-04 3.3367E-05 -5.5223E-05 S13 -1.8777E-04 -6.0408E-04 7.0210E-04 1.1716E-03 1.0190E-04 -4.1769E-05 -6.5787E-05 S14 -1.0659E-02 3.8987E-03 -4.1868E-03 2.4659E-03 4.1884E-04 4.2216E-04 -3.5996E-04 S15 4.0720E-03 -2.0298E-03 -7.9957E-03 6.0581E-03 -4.1460E-03 4.3823E-03 9.2538E-05 S16 2.5783E-02 -1.0073E-02 2.7265E-03 5.8446E-04 -5.3541E-04 4.2243E-04 -2.2597E-04

[0116] Table 8-2

[0117] Figure 8A The axial chromatic aberration curve of the optical imaging system of Example 4 is shown, which indicates the deviation of the focal point of light of different wavelengths after passing through the lens. Figure 8B The astigmatism curve of the optical imaging system of Example 4 is shown, which represents the meridional field curvature and the sagittal field curvature. Figure 8A and Figure 8B It can be seen that the optical imaging system provided in Example 4 can achieve good imaging quality.

[0118] Example 5

[0119] The following reference Figures 9-10B An optical imaging system according to Example 5 of the present application is described. Figure 9 A structural schematic diagram of an optical imaging system according to Example 5 of the present application is shown.

[0120] like Figure 9 As shown, the optical imaging system includes, from the object side to the image side, a first lens E1, a second lens E2, an aperture STO, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, an eighth lens E8, a filter E9 and an imaging surface S19.

[0121] The first lens E1 has negative focal power, with a concave object side surface S1 and a concave image side surface S2. The second lens E2 has positive focal power, with a convex object side surface S3 and a convex image side surface S4. The third lens E3 has positive focal power, with a convex object side surface S5 and a convex image side surface S6. The fourth lens E4 has positive focal power, with a concave object side surface S7 and a convex image side surface S8. The fifth lens E5 has negative focal power, with a concave object side surface S9 and a convex image side surface S10. The sixth lens E6 has negative focal power, with a concave object side surface S11 and a concave image side surface S12. The seventh lens E7 has positive focal power, with a convex object side surface S13 and a convex image side surface S14. The eighth lens E8 has negative focal power, with a convex object side surface S15 and a concave image side surface S16. The filter E9 has an object side surface S17 and an image side surface S18. Light from an object passes through the surfaces S1 to S18 in sequence and is ultimately imaged on an image plane S19.

[0122] In this example, the total effective focal length f of the optical imaging system is 2.24 mm, the half of the maximum field of view angle Semi-FOV of the optical imaging system is 72.6°, and the F number Fno of the optical imaging system is 2.30.

[0123] Table 9 shows a list of basic parameters of the optical imaging system of Example 5, where the units of the radius of curvature, thickness / distance, and focal length are all in millimeters (mm). Tables 10-1, 10-2 show the high order term coefficients of the aspherical surfaces that can be used in the optical imaging system of Example 5, where each aspherical surface can be defined by the formula (1) given in Example 1 above.

[0124]

[0125]

[0126] Table 9

[0127] Face Number A4 A6 A8 A10 A12 A14 A16 S1 1.7940E+00 -3.9759E-01 1.3722E-01 -5.4571E-02 2.4328E-02 -1.1263E-02 5.0325E-03 S2 4.1671E-01 -5.8081E-02 1.2847E-02 -8.8933E-03 3.8743E-04 1.1932E-04 2.8856E-04 S3 1.0088E-01 8.5512E-03 -7.0354E-03 -4.1129E-03 -2.7665E-04 2.8081E-04 2.6917E-04 S4 1.0289E-01 6.1802E-03 -7.0612E-04 -4.4115E-04 -5.1901E-05 8.9927E-06 2.7644E-05 S5 1.5159E-02 5.0506E-04 3.1854E-05 2.6782E-06 2.4301E-07 7.0574E-08 5.6019E-07 S6 1.4818E-02 7.2849E-03 7.3226E-04 3.8393E-05 -9.0516E-05 -4.7704E-05 -2.6521E-05 S7 2.9043E-03 -2.2865E-03 7.0554E-05 6.8929E-04 3.9844E-04 7.7973E-05 1.4290E-05 S8 -1.7901E-01 -1.4878E-02 4.8582E-03 -1.3454E-04 1.9353E-03 -2.5633E-04 9.0071E-04 S9 -3.0894E-01 -6.5161E-03 2.0862E-02 7.2349E-04 1.9997E-03 -2.1679E-03 7.8230E-04 S10 -6.0328E-02 -2.4349E-02 2.4201E-02 -7.4538E-03 4.8733E-03 -1.7593E-03 7.4240E-04 S11 1.8588E-01 -1.9709E-01 3.2077E-02 -1.9022E-02 7.5219E-03 -3.2077E-03 2.5558E-03 S12 -1.5726E+00 2.9335E-01 -8.7210E-02 3.6469E-02 -1.9416E-02 6.9307E-03 -8.0664E-04 S13 -3.1601E+00 3.7575E-01 -5.6692E-02 2.4925E-02 -8.8211E-03 -3.5051E-03 -5.1266E-03 S14 2.2631E+00 -7.8284E-01 2.4362E-01 -1.2947E-01 9.7937E-02 -7.5784E-02 3.9456E-02 S15 -4.6924E+00 1.2188E+00 -5.1264E-01 2.0649E-01 -7.5218E-02 6.0062E-03 2.3934E-02 S16 -9.7874E+00 2.1459E+00 -8.3238E-01 3.2639E-01 -1.8999E-01 8.3354E-02 -2.3690E-02

[0128] Table 10-1

[0129] Face Number A18 A20 A22 A24 A26 A28 A30 S1 -2.7405E-03 8.7195E-04 -8.3294E-04 2.7675E-05 -2.6837E-04 -2.7903E-05 -4.8219E-05 S2 2.0581E-04 -1.8270E-05 7.8482E-06 -2.9893E-05 7.5192E-06 -3.1880E-06 8.6450E-07 S3 1.1169E-04 -1.6598E-05 -6.1641E-06 -1.8883E-05 4.1441E-06 -2.7636E-06 7.0965E-06 S4 -2.4942E-06 5.7850E-06 -1.4077E-06 3.8307E-06 4.7360E-07 1.6070E-06 -1.5218E-06 S5 2.2248E-07 2.2114E-07 -1.2662E-06 4.2558E-07 -3.0289E-08 0.0000E+00 0.0000E+00 S6 -2.0490E-06 3.8741E-06 5.6434E-06 1.9073E-06 3.6992E-07 0.0000E+00 0.0000E+00 S7 -2.9895E-05 -9.2660E-06 -3.2236E-06 1.2957E-06 8.9312E-07 0.0000E+00 0.0000E+00 S8 3.2982E-04 3.0706E-04 4.4664E-05 1.3320E-05 -2.5373E-05 -3.8244E-06 -9.3310E-06 S9 3.9533E-04 2.9435E-04 -1.4204E-04 -1.5030E-04 -9.9535E-05 -1.2824E-05 -8.2917E-07 S10 -3.0280E-04 9.2482E-05 -3.7689E-05 5.1373E-06 -8.4033E-07 -5.3675E-06 1.1452E-06 S11 -8.1537E-05 4.9613E-04 -1.6118E-04 6.1264E-05 -1.2097E-05 1.7448E-05 -6.1585E-06 S12 6.3780E-04 -9.1459E-04 6.7039E-04 -9.9522E-05 -6.1345E-07 -1.1119E-04 1.1142E-04 S13 4.8888E-03 1.0596E-03 1.8784E-03 4.0223E-04 1.5956E-04 -1.1612E-03 1.1873E-04 S14 -2.0864E-02 1.5828E-02 -6.3186E-03 5.5399E-03 -2.8396E-03 5.0260E-05 -3.0885E-05 S15 -2.9711E-02 2.7426E-02 -2.0508E-02 1.8421E-02 -1.3591E-02 5.2945E-03 -8.3504E-04 S16 7.3569E-03 -1.5099E-02 -8.5545E-03 1.0305E-02 5.6612E-03 1.2983E-03 -2.8414E-03

[0130] Table 10-2

[0131] Figure 10A The on-axis chromatic aberration curve of the optical imaging system of Example 5 is shown, which represents the deviation of the converging focal points of light rays of different wavelengths after passing through the lens. Figure 10B The astigmatism curve of the optical imaging system of Example 5 is shown, which represents the meridional image curvature and sagittal image curvature. According to the formula (2) given above, the maximum absolute value of the sagittal image curvature is 0.002 mm-1, and the maximum absolute value of the meridional image curvature is 0.002 mm-1. Figure 10A and Figure 10B It can be seen that the optical imaging system given in Example 5 can achieve good imaging quality.

[0132] In summary, Embodiments 1 to 5 respectively satisfy the relationships shown in Table 11.

[0133] Conditional / Example 1 2 3 4 5 f2 / f1+R2 / R1 -3.52 -3.64 -3.52 -3.61 -3.94 CT2 / CT1+TAN (Semi-FOV) 4.08 4.02 4.52 4.07 4.54 (R5-R6) / (R5+R6) -2.85 -2.99 -2.64 -2.74 -3.51 f3 / CT3+|R6| / f3 10.24 10.04 10.04 10.09 9.81 (f4+f5) / (R8+R9) 1.26 1.09 1.07 1.08 0.56 f5 / R10+CT5 / T45 5.53 5.39 5.18 5.67 5.62 T56 / CT6+|f6| / R12 2.47 2.88 3.02 3.04 3.07 f7 / R13+f8 / R15 -8.77 -2.00 -1.98 -2.77 -1.06 (SAG61+SAG62) / (SAG61-SAG62) 1.82 3.71 3.98 2.93 1.64 (SAG72+SAG81) / SAG82 2.41 2.59 2.19 2.38 1.42 f56 / (CT5+CT6) -3.42 -4.17 -4.12 -4.28 -2.32 f67 / (R12+R13) 1.78 1.09 1.09 1.25 0.96 f78 / R16+CT7 / CT8 3.42 4.25 4.25 3.97 4.13

[0134] Table 11

[0135] The present application also provides an imaging device, the electronic photosensitive element of which can be a charge-coupled device (CCD) or a complementary metal-oxide-semiconductor device (CMOS). The imaging device can be a stand-alone imaging apparatus such as a digital camera, or an imaging module integrated on a mobile electronic device such as a mobile phone. The imaging device is equipped with the optical imaging system described above.

[0136] The above description is merely preferred embodiments of the present application and a description of the principles of the technology used. It should be understood by those skilled in the art that the scope of the application involved in the present application is not limited to the technical solutions formed by the specific combinations of the technical features described above, and should also cover other technical solutions formed by any combination of the above technical features or equivalent features without departing from the inventive concept. For example, the technical solutions formed by the mutual replacement of the above features and the technical features disclosed in the present application (but not limited to) having similar functions.

Claims

1. An optical imaging system, characterized in that Along the optical axis from the object side to the image side, they include: The first lens has a negative optical power, and its object-side surface is concave and its image-side surface is concave; a second lens having positive optical power and a convex object-side surface; The third lens has positive optical power, its object-side surface is convex, and its image-side surface is convex; a fourth lens element having positive refractive power and a convex image-side surface; a fifth lens element having negative optical power, whose object-side surface is concave and whose image-side surface is convex; a sixth lens element having negative optical power and a concave image-side surface; a seventh lens element having positive optical power and a convex object-side surface; and an eighth lens element having negative optical power, the object-side surface of which is convex and the image-side surface of which is concave; Wherein, the number of lenses having optical power in the optical imaging system is eight; The Abbe numbers of at least four lenses from the first lens to the eighth lens are within a range of 20.4 to 25.9; There is an air gap between any two adjacent lenses from the first lens to the eighth lens; At least one of the mirror surfaces from the object side surface of the first lens to the image side surface of the eighth lens is an aspherical mirror surface; and The optical imaging system satisfies the following conditions: 4.0<CT2 / CT1+TAN(Semi-FOV)≤4.54 and 0.96≤f67 / (R12+R13)≤1.78, where Semi-FOV is half of the maximum field of view of the optical imaging system, CT1 is the center thickness of the first lens on the optical axis, CT2 is the center thickness of the second lens on the optical axis, f67 is the combined focal length of the sixth lens and the seventh lens, R12 is the radius of curvature of the image side surface of the sixth lens, and R13 is the radius of curvature of the object side surface of the seventh lens.

2. The optical imaging system according to claim 1, wherein: The optical imaging system satisfies: -3.94≤f2 / f1+R2 / R1<-3.5, where f1 is the effective focal length of the first lens, f2 is the effective focal length of the second lens, R1 is the curvature radius of the object side surface of the first lens, and R2 is the curvature radius of the image side surface of the first lens.

3. The optical imaging system according to claim 1, wherein: The optical imaging system satisfies: -3.51≤(R5-R6) / (R5+R6)≤-2.64, wherein R5 is the curvature radius of the object side surface of the third lens, and R6 is the curvature radius of the image side surface of the third lens.

4. The optical imaging system according to claim 1, wherein: The optical imaging system satisfies the following: 9.81≤f3 / CT3+|R6| / f3≤10.24, where f3 is the effective focal length of the third lens, R6 is the radius of curvature of the image side surface of the third lens, and CT3 is the center thickness of the third lens on the optical axis.

5. The optical imaging system according to claim 1, wherein: The optical imaging system satisfies the following: 0.56≤(f4+f5) / (R8+R9)≤1.26, where f4 is the effective focal length of the fourth lens, f5 is the effective focal length of the fifth lens, R8 is the curvature radius of the image side surface of the fourth lens, and R9 is the curvature radius of the object side surface of the fifth lens.

6. The optical imaging system according to claim 1, wherein: The optical imaging system satisfies the following: 5.18≤f5 / R10+CT5 / T45≤5.67, where f5 is the effective focal length of the fifth lens, R10 is the radius of curvature of the image-side surface of the fifth lens, CT5 is the center thickness of the fifth lens on the optical axis, and T45 is the air spacing between the fourth lens and the fifth lens on the optical axis.

7. The optical imaging system according to claim 1, wherein: The optical imaging system satisfies the following: 2.47≤T56 / CT6+|f6| / R12≤3.07, where T56 is the air spacing between the fifth lens and the sixth lens on the optical axis, CT6 is the center thickness of the sixth lens on the optical axis, f6 is the effective focal length of the sixth lens, and R12 is the curvature radius of the image side surface of the sixth lens.

8. The optical imaging system according to claim 1, wherein: The optical imaging system satisfies: -8.77≤f7 / R13+f8 / R15≤-1.06, where f7 is the effective focal length of the seventh lens, f8 is the effective focal length of the eighth lens, R13 is the curvature radius of the object side surface of the seventh lens, and R15 is the curvature radius of the object side surface of the eighth lens.

9. The optical imaging system according to claim 1, wherein: The optical imaging system satisfies: 1.64≤(SAG61+SAG62) / (SAG61-SAG62)≤3.98, wherein SAG61 is the distance from the intersection of the object side surface of the sixth lens and the optical axis to the vertex of the effective radius of the object side surface of the sixth lens on the optical axis, and SAG62 is the distance from the intersection of the image side surface of the sixth lens and the optical axis to the vertex of the effective radius of the image side surface of the sixth lens on the optical axis.

10. The optical imaging system according to claim 1, wherein: The optical imaging system satisfies: 1.42≤(SAG72+SAG81) / SAG82≤2.59, wherein SAG72 is the distance from the intersection of the image side surface of the seventh lens and the optical axis to the effective radius vertex of the image side surface of the seventh lens on the optical axis, SAG81 is the distance from the intersection of the object side surface of the eighth lens and the optical axis to the effective radius vertex of the object side surface of the eighth lens on the optical axis, and SAG82 is the distance from the intersection of the image side surface of the eighth lens and the optical axis to the effective radius vertex of the image side surface of the eighth lens on the optical axis.

11. The optical imaging system according to any one of claims 1 to 10, characterized in that: The optical imaging system satisfies the following: -4.28≤f56 / (CT5+CT6)≤-2.32, where f56 is the combined focal length of the fifth lens and the sixth lens, CT5 is the center thickness of the fifth lens on the optical axis, and CT6 is the center thickness of the sixth lens on the optical axis.

12. The optical imaging system according to any one of claims 1 to 10, characterized in that: The optical imaging system satisfies the following: 3.42≤f78 / R16+CT7 / CT8≤4.25, where f78 is the combined focal length of the seventh lens and the eighth lens, R16 is the radius of curvature of the image-side surface of the eighth lens, CT7 is the center thickness of the seventh lens on the optical axis, and CT8 is the center thickness of the eighth lens on the optical axis.

13. The optical imaging system according to any one of claims 1 to 10, characterized in that: The optical imaging system satisfies: V8=20.4, where V8 is the Abbe number of the eighth lens.

Images