An optical imaging system

Abstract

The present invention discloses an optical imaging system, which includes, in order from the object side to the image side along the optical axis: a first lens; a second lens with negative optical focal length; a third lens; a fourth lens, whose image side surface is concave; a fifth lens; a sixth lens with negative optical focal length; a seventh lens, whose object side surface is convex and whose image side surface is concave; and an eighth lens; wherein the axial distance TTL from the object side surface of the first lens to the imaging surface and the half of the diagonal length of the effective pixel area on the imaging surface ImgH satisfy: TTL / ImgH≦1.4. By limiting the optical focal length and surface shape of the second lens, the fourth lens, the fifth lens and the seventh lens, the optical imaging system can have good imaging quality; by constraining the ratio of the axial distance from the object side surface of the first lens to the imaging surface and the half of the diagonal length of the effective pixel area on the imaging surface, the ultra-thinness and high pixel of the optical imaging system can be simultaneously achieved.

Description

Technical Field

[0001] The invention belongs to the field of optical imaging, and in particular relates to an optical imaging system comprising eight lenses. Background Art

[0002] Smartphones have greatly improved the performance of imaging systems and have greatly changed people's lives. In order to continuously improve the quality of imaging, more improvements have been applied to optical imaging systems with small structures. At present, the image size of mobile phone imaging systems is on a continuous increase, and optical lenses generally meet the requirements by increasing the number of lenses, but this is contrary to the miniaturization requirements of smartphones. Traditional lenses installed in portable electronic products mostly use three-piece or four-piece lens structures, and the existing optical systems can no longer meet the needs of higher-order photography systems. With the development of technology and the increase in diversified user needs, in order to obtain better imaging quality, five-piece, six-piece, and seven-piece lens structures have gradually appeared in the design of optical imaging systems.

[0003] In order to achieve the requirements of miniaturization, lightness and thinness as much as possible, and to ensure that the imaging effect of the optical lens meets the requirements, this brings higher difficulty and challenges to lens design. Therefore, how to select suitable materials, reasonable lens refractive index configuration and shape, and finally make the lens group into an ultra-thin and high-resolution lens group is a problem that needs to be solved at present.

[0004] The technical solution of the present application achieves good imaging quality by reasonably distributing the optical power of 8 lenses. At the same time, by introducing the first piece of GM molded material, the overall length of the system is reduced, meeting the requirements of lightness, thinness and miniaturization. Summary of the invention

[0005] The present application aims to provide an optical imaging system composed of eight lenses, which has the characteristics of ultra-thinness and good imaging quality.

[0006] The present application provides an optical imaging system, which includes, in order from the object side to the image side along the optical axis:

[0007] First lens;

[0008] a second lens having negative optical power;

[0009] The third lens;

[0010] The fourth lens has a concave image side surface;

[0011] The fifth lens;

[0012] a sixth lens having negative optical power;

[0013] The seventh lens has a convex object side surface and a concave image side surface;

[0014] The eighth lens;

[0015] The axial distance TTL from the object side of the first lens to the imaging plane and half the diagonal length of the effective pixel area on the imaging plane ImgH satisfy: TTL / ImgH≦1.4.

[0016] According to one embodiment of the present application, the effective focal length f1 of the first lens, the effective focal length f7 of the seventh lens, and half of the maximum field of view Semi-FOV of the optical imaging system satisfy: 1.0≦f7 / f×tan(Semi-FOV)≦1.2.

[0017] According to one embodiment of the present application, the center thickness CT1 of the first lens on the optical axis, the center thickness CT2 of the second lens on the optical axis, the center thickness CT3 of the third lens on the optical axis, the air interval T34 between the third lens and the fourth lens on the optical axis, and the distance BFL from the image side surface to the imaging surface of the last lens of the optical imaging system on the optical axis satisfy: 0.5≦(CT1+CT2+CT3-T34) / BFL≦1.2.

[0018] According to one embodiment of the present application, a curvature radius R13 of the object-side surface of the seventh lens and a curvature radius R14 of the image-side surface of the seventh lens satisfy: 16≦f7 / R13+f7 / R14≦20.

[0019] According to one embodiment of the present application, a curvature radius R13 of the object-side surface of the seventh lens and a curvature radius R14 of the image-side surface of the seventh lens satisfy: 1.5≦|(R13+R14) / (R13-R14)|≦3.5.

[0020] According to one embodiment of the present application, the effective focal length f7 of the seventh lens and the effective focal length f8 of the eighth lens satisfy: 0.5≦|f7 / f8|≦1.5.

[0021] According to one embodiment of the present application, a radius of curvature R3 of the object side surface of the second lens and a radius of curvature R4 of the image side surface of the second lens satisfy: 1.4≦R3 / R4≦1.7.

[0022] According to one embodiment of the present application, the effective focal length f5 of the fifth lens, the effective focal length f6 of the sixth lens, and the effective focal length f of the optical imaging system satisfy: 0.5≦|(f5+f6) / f|≦5.7.

[0023] According to one embodiment of the present application, the combined focal length f234 of the second lens, the third lens, and the fourth lens satisfies: -4.0≦f234 / f≦-2.0.

[0024] According to one embodiment of the present application, the on-axis distance TTL from the object side of the first lens to the imaging plane and the sum of the air interval ΣAT on the optical axis between any two adjacent lenses with optical power from the first lens to the lens closest to the imaging plane satisfy: 2.5≦TTL / ΣAT≦3.0.

[0025] According to one embodiment of the present application, the effective focal length f1 of the first lens and the effective focal length f4 of the fourth lens satisfy: 2.0≦|f4 / f1|≦3.5.

[0026] According to one embodiment of the present application, the on-axis distance SL from the aperture to the imaging plane and the distance BFL from the image side surface of the last lens of the optical imaging system to the imaging plane on the optical axis satisfy: 6.5≦SL / BFL≦8.5.

[0027] According to one embodiment of the present application, the combined focal length f4567 of the fourth lens, the fifth lens, the sixth lens, and the seventh lens satisfies: 1.0≦f4567 / f≦1.5.

[0028] The present application also provides an optical imaging system, which includes, in order from the object side to the image side along the optical axis:

[0029] First lens;

[0030] a second lens having negative optical power;

[0031] The third lens;

[0032] The fourth lens;

[0033] The fifth lens has a convex object side surface and a convex image side surface;

[0034] a sixth lens having negative optical power;

[0035] The seventh lens;

[0036] The eighth lens has a convex object side surface and a concave image side surface;

[0037] The axial distance TTL from the object side of the first lens to the imaging plane and half the diagonal length of the effective pixel area on the imaging plane ImgH satisfy: TTL / ImgH≦1.4.

[0038] According to one embodiment of the present application, the effective focal length f1 of the first lens, the effective focal length f7 of the seventh lens, and half of the maximum field of view Semi-FOV of the optical imaging system satisfy: 1.0≦f7 / f×tan(Semi-FOV)≦1.2.

[0039] According to one embodiment of the present application, the center thickness CT1 of the first lens on the optical axis, the center thickness CT2 of the second lens on the optical axis, the center thickness CT3 of the third lens on the optical axis, the air interval T34 between the third lens and the fourth lens on the optical axis, and the distance BFL from the image side surface to the imaging surface of the last lens of the optical imaging system on the optical axis satisfy: 0.5≦(CT1+CT2+CT3-T34) / BFL≦1.2.

[0040] According to one embodiment of the present application, a curvature radius R13 of the object-side surface of the seventh lens and a curvature radius R14 of the image-side surface of the seventh lens satisfy: 16≦f7 / R13+f7 / R14≦20.

[0041] According to one embodiment of the present application, a curvature radius R13 of the object-side surface of the seventh lens and a curvature radius R14 of the image-side surface of the seventh lens satisfy: 1.5≦|(R13+R14) / (R13-R14)|≦3.5.

[0042] According to one embodiment of the present application, the effective focal length f7 of the seventh lens and the effective focal length f8 of the eighth lens satisfy: 0.5≦|f7 / f8|≦1.5.

[0043] According to one embodiment of the present application, a radius of curvature R3 of the object side surface of the second lens and a radius of curvature R4 of the image side surface of the second lens satisfy: 1.4≦R3 / R4≦1.7.

[0044] According to one embodiment of the present application, the effective focal length f5 of the fifth lens, the effective focal length f6 of the sixth lens, and the effective focal length f of the optical imaging system satisfy: 0.5≦|(f5+f6) / f|≦5.7.

[0045] According to one embodiment of the present application, the combined focal length f234 of the second lens, the third lens, and the fourth lens satisfies: -4.0≦f234 / f≦-2.0.

[0046] According to one embodiment of the present application, the on-axis distance TTL from the object side of the first lens to the imaging plane and the sum of the air interval ΣAT on the optical axis between any two adjacent lenses with optical power from the first lens to the lens closest to the imaging plane satisfy: 2.5≦TTL / ΣAT≦3.0.

[0047] According to one embodiment of the present application, the effective focal length f1 of the first lens and the effective focal length f4 of the fourth lens satisfy: 2.0≦|f4 / f1|≦3.5.

[0048] According to one embodiment of the present application, the on-axis distance SL from the aperture to the imaging plane and the distance BFL from the image side surface of the last lens of the optical imaging system to the imaging plane on the optical axis satisfy: 6.5≦SL / BFL≦8.5.

[0049] According to one embodiment of the present application, the combined focal length f4567 of the fourth lens, the fifth lens, the sixth lens, and the seventh lens satisfies: 1.0≦f4567 / f≦1.5.

[0050] Beneficial effects of the present invention:

[0051] The optical imaging system provided by the present invention includes multiple lenses, such as the first lens to the eighth lens. By limiting the optical power and surface shape of the second lens, the fourth lens, the fifth lens and the seventh lens, the optical imaging system can have good imaging quality; by constraining the ratio of the on-axis distance from the object side of the first lens to the imaging surface and half the diagonal length of the effective pixel area on the imaging surface, the optical imaging system can be ultra-thin and high-pixel at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0053] Figure 1 Schematic diagram of the lens group structure of embodiment 1 of the optical imaging system of the present invention;

[0054] Figure 2a and Figure 2b They are respectively an axial chromatic aberration curve and an astigmatism curve of the optical imaging system embodiment 1 of the present invention;

[0055] Figure 3 Schematic diagram of the lens group structure of embodiment 2 of the optical imaging system of the present invention;

[0056] Figure 4a and Figure 4b They are respectively an axial chromatic aberration curve and an astigmatism curve of Embodiment 2 of the optical imaging system of the present invention;

[0057] Figure 5 Schematic diagram of the lens group structure of embodiment 3 of the optical imaging system of the present invention;

[0058] Figure 6a and Figure 6b They are respectively an axial chromatic aberration curve and an astigmatism curve of Embodiment 3 of the optical imaging system of the present invention;

[0059] Figure 7 Schematic diagram of the lens group structure of embodiment 4 of the optical imaging system of the present invention;

[0060] Figure 8a and Figure 8bThey are respectively an axial chromatic aberration curve and an astigmatism curve of Embodiment 4 of the optical imaging system of the present invention;

[0061] Fig. 9 Schematic diagram of the lens group structure of embodiment 5 of the optical imaging system of the present invention;

[0062] Fig.10a and Fig.10b They are respectively an axial chromatic aberration curve and an astigmatism curve of Embodiment 5 of the optical imaging system of the present invention;

[0063] Fig.11 Schematic diagram of the lens group structure of embodiment 6 of the optical imaging system of the present invention;

[0064] Fig.12a and Figure 12b They are respectively the axial chromatic aberration curve and the astigmatism curve of Example 6 of the optical imaging system of the present invention. DETAILED DESCRIPTION

[0065] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0066] It should be noted that in this specification, the expressions of first, second, third, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the features. Therefore, without departing from the teaching of the present invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0067] It should also be understood that the terms "comprises", "including", "having", "includes" 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. In addition, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire listed features rather than modifying the individual elements in the list. In addition, when describing embodiments of the present application, "may" is used to mean "one or more embodiments of the present application". And, the term "exemplary" is intended to refer to an example or illustration.

[0068] In the drawings, the thickness, size and shape of the lenses have been slightly exaggerated for ease of explanation. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to the shapes of the spherical or aspherical surfaces shown in the drawings. The drawings are only examples and are not drawn strictly to scale.

[0069] In the description of the present invention, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface is not defined, it means that the lens surface is convex at least in the paraxial region. If the lens surface is concave and the position of the concave surface is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is called the object side of the lens, and the surface of each lens closest to the imaging plane is called the image side of the lens.

[0070] Unless otherwise defined, all terms (including technical terms and scientific terms) used in this article have the same meaning as commonly understood by ordinary technicians in the field to which this application belongs. It should also be understood that terms (such as terms defined in commonly used dictionaries) should be interpreted as having the same meaning as their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal way unless explicitly defined in this article.

[0071] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The features, principles and other aspects of the present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0072] Exemplary Embodiments

[0073] The optical imaging system of the exemplary embodiment of the present invention includes eight lenses, which include: 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 in order from the object side to the image side along the optical axis, wherein the second lens has a negative optical power; the image side surface of the fourth lens is a concave surface; the sixth lens has a negative optical power; the object side surface of the seventh lens is a convex surface, and the image side surface is a concave surface. By limiting the optical power and surface shape of the second lens, the fourth lens, the fifth lens and the seventh lens, the optical imaging system can have good imaging quality.

[0074] The optical imaging system of another exemplary embodiment of the present invention includes eight lenses, which include: 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 in order from the object side to the image side along the optical axis, wherein the second lens has a negative optical power; the object side surface of the fifth lens is a convex surface, and the image side surface is a convex surface; the sixth lens has a negative optical power; the object side surface of the eighth lens is a convex surface, and the image side surface is a concave surface. By limiting the optical power and surface shape of the second lens, the fifth lens, the sixth lens and the eighth lens, the optical imaging system can have good imaging quality.

[0075] In this exemplary embodiment, the axial distance TTL from the object side of the first lens to the imaging surface and half of the diagonal length of the effective pixel area on the imaging surface ImgH satisfy: TTL / ImgH≦1.4. By constraining the ratio of the axial distance from the object side of the first lens to the imaging surface and half of the diagonal length of the effective pixel area on the imaging surface, ultra-thinness and high pixel count of the optical imaging system can be achieved simultaneously. More specifically, the axial distance TTL from the object side of the first lens to the imaging surface and half of the diagonal length of the effective pixel area on the imaging surface ImgH satisfy: TTL / ImgH≦1.35.

[0076] In this exemplary embodiment, the effective focal length f1 of the first lens, the effective focal length f7 of the seventh lens, and the half of the maximum field of view of the optical imaging system Semi-FOV satisfy: 1.0≦f7 / f×tan(Semi-FOV)≦1.2. By adjusting the effective focal length of the first lens, the effective focal length of the seventh lens, and the half of the maximum field of view of the optical imaging system, it is possible to ensure that the chip with a large image surface is matched, so that the system has the characteristics of high pixels, low sensitivity, and easy processing. More specifically, the effective focal length f1 of the first lens, the effective focal length f7 of the seventh lens, and the half of the maximum field of view of the optical imaging system Semi-FOV satisfy: 1.0≦f7 / f×tan(Semi-FOV)≦1.18.

[0077] In this exemplary embodiment, the center thickness CT1 of the first lens on the optical axis, the center thickness CT2 of the second lens on the optical axis, the center thickness CT3 of the third lens on the optical axis, the air interval T34 between the third lens and the fourth lens on the optical axis, and the distance BFL from the image side of the last lens of the optical imaging system to the imaging plane on the optical axis satisfy: 0.5≦(CT1+CT2+CT3-T34) / BFL≦1.2. By constraining the center thickness of the first lens on the optical axis, the center thickness of the second lens on the optical axis, the center thickness of the third lens on the optical axis, the air interval between the third lens and the fourth lens on the optical axis, and the ratio of the distance from the image side of the last lens of the optical imaging system to the imaging plane on the optical axis to be limited within a reasonable range, the distortion contribution of the fourth lens is adjusted to compensate for the distortion generated by the lens at the rear end close to the image plane. More specifically, the center thickness CT1 of the first lens on the optical axis, the center thickness CT2 of the second lens on the optical axis, the center thickness CT3 of the third lens on the optical axis, the air interval T34 between the third lens and the fourth lens on the optical axis, and the distance BFL from the image side surface to the imaging surface of the last lens of the optical imaging system on the optical axis satisfy: 0.75≦(CT1+CT2+CT3-T34) / BFL≦1.0.

[0078] In this exemplary embodiment, the curvature radius R13 of the object side surface of the seventh lens and the curvature radius R14 of the image side surface of the seventh lens satisfy: 16≦f7 / R13+f7 / R14≦20. By controlling the ratio of the effective focal length of the seventh lens to the curvature radius of the object side surface of the seventh lens, and the ratio of the effective focal length of the seventh lens to the curvature radius of the image side surface of the seventh lens, the optical power and lens shape of the seventh lens can be controlled to meet the processability requirements. More specifically, the curvature radius R13 of the object side surface of the seventh lens and the curvature radius R14 of the image side surface of the seventh lens satisfy: 17.45≦f7 / R13+f7 / R14≦19.30.

[0079] In this exemplary embodiment, the radius of curvature R13 of the object side of the seventh lens and the radius of curvature R14 of the image side of the seventh lens satisfy: 1.5≦|(R13+R14) / (R13-R14)|≦3.5. By controlling this conditional expression within a reasonable range, the contribution rate of its third-order astigmatism can be controlled to a certain extent, so that the third-order astigmatism of the fourth lens is within a reasonable range, achieving the effect of high resolution at macro distances. More specifically, the radius of curvature R13 of the object side of the seventh lens and the radius of curvature R14 of the image side of the seventh lens satisfy: 2.30≦|(R13+R14) / (R13-R14)|≦3.40.

[0080] In this exemplary embodiment, the effective focal length f7 of the seventh lens and the effective focal length f8 of the eighth lens satisfy: 0.5≦|f7 / f8|≦1.5. By reasonably controlling the focal length ratio of the seventh lens and the eighth lens within a certain range, the aberrations generated by the seventh lens and the eighth lens can be balanced, the contribution of the lens aberrations can be controlled, the system aberrations are at a reasonable level, and the optical imaging system has good imaging quality. More specifically, the effective focal length f7 of the seventh lens and the effective focal length f8 of the eighth lens satisfy: 1.24≦|f7 / f8|≦1.41.

[0081] In this exemplary embodiment, the radius of curvature R3 of the object side surface of the second lens and the radius of curvature R4 of the image side surface of the second lens satisfy: 1.4≦R3 / R4≦1.7. By limiting the ratio range of the object side curvature radius and the image side curvature radius of the second lens, the shape of the second lens can be effectively constrained, thereby effectively controlling the aberration contribution of the object side and image side surfaces of the second lens, thereby effectively improving the imaging quality of the system. More specifically, the radius of curvature R3 of the object side surface of the second lens and the radius of curvature R4 of the image side surface of the second lens satisfy: 1.45≦R3 / R4≦1.65.

[0082] In this exemplary embodiment, the effective focal length f5 of the fifth lens, the effective focal length f6 of the sixth lens, and the effective focal length f of the optical imaging system satisfy: 0.5≦|(f5+f6) / f|≦5.7. By reasonably controlling the ratio of the sum of the fifth lens and the sixth lens to the focal length of the system within a certain range, the aberrations produced by the combination of the fifth lens and the sixth lens can be balanced, the contribution of the lens aberrations can be controlled, and the system aberrations can be kept at a reasonable level, thereby making the optical imaging system have good imaging quality. More specifically, the effective focal length f5 of the fifth lens, the effective focal length f6 of the sixth lens, and the effective focal length f of the optical imaging system satisfy: 1.80≦|(f5+f6) / f|≦5.65.

[0083] In this exemplary embodiment, the combined focal length f234 of the second lens, the third lens, and the fourth lens satisfies: -4.0≦f234 / f≦-2.0. By reasonably controlling the ratio of the combined focal length of the second lens, the third lens, and the fourth lens to the system focal length within a certain range, the aberrations generated by the combination of the second lens, the third lens, and the fourth lens can be balanced, the contribution of the lens aberrations can be controlled, and the system aberrations can be kept at a reasonable level, thereby making the optical imaging system have good imaging quality. More specifically, the combined focal length f234 of the second lens, the third lens, and the fourth lens satisfies: -2.90≦f234 / f≦-2.10.

[0084] In this exemplary embodiment, the on-axis distance TTL from the object side of the first lens to the imaging surface and the sum of the air intervals on the optical axis ∑AT between the first lens and any two adjacent lenses with optical power among the lenses closest to the imaging surface satisfy: 2.5≦TTL / ΣAT≦3.0. By reasonably controlling the ratio of the on-axis distance from the object side of the first lens to the imaging surface and the sum of the air intervals on the optical axis between the first lens and any two adjacent lenses with optical power among the lenses closest to the imaging surface within a certain reasonable range, a more dense and reasonable arrangement of the lens structure within a limited space size is achieved, and ultra-thin and miniaturized lens is achieved. More specifically, the on-axis distance TTL from the object side of the first lens to the imaging surface and the sum of the air intervals on the optical axis ∑AT between the first lens and any two adjacent lenses with optical power among the lenses closest to the imaging surface satisfy: 2.51≦TTL / ΣAT≦2.95.

[0085] In this exemplary embodiment, the effective focal length f1 of the first lens and the effective focal length f4 of the fourth lens satisfy: 2.0≦|f4 / f1|≦3.5. By reasonably controlling the ratio of the effective focal length of the fourth lens to the effective focal length of the first lens within a certain range, it is possible to achieve a reasonable distribution of the optical power of the fourth lens and the first lens, reduce system aberrations, and improve system imaging quality. More specifically, the effective focal length f1 of the first lens and the effective focal length f4 of the fourth lens satisfy: 2.1≦|f4 / f1|≦3.10.

[0086] In this exemplary embodiment, the on-axis distance SL from the aperture to the imaging plane and the distance BFL from the image side of the last lens of the optical imaging system to the imaging plane on the optical axis satisfy: 6.5≦SL / BFL≦8.5. By reasonably controlling the ratio of the on-axis distance from the aperture to the imaging plane and the distance from the image side of the last lens of the optical imaging system to the imaging plane on the optical axis within a certain range, the aberrations generated by the front and rear combinations can be balanced, the contribution of the lens aberrations can be controlled, the system aberrations can be kept at a reasonable level, and the optical imaging system can have good imaging quality. More specifically, the on-axis distance SL from the aperture to the imaging plane and the distance BFL from the image side of the last lens of the optical imaging system to the imaging plane on the optical axis satisfy: 6.80≦SL / BFL≦7.80.

[0087] In this exemplary embodiment, the combined focal length f4567 of the fourth lens, the fifth lens, the sixth lens, and the seventh lens satisfies: 1.0≦f4567 / f≦1.5. By reasonably controlling the ratio of the combined focal length of the fourth lens to the seventh lens to the system focal length within a certain range, the aberrations generated by the front and rear combinations can be balanced, the contribution of the lens aberrations can be controlled, and the system aberrations can be kept at a reasonable level, thereby enabling the optical imaging system to have good imaging quality. More specifically, the combined focal length f4567 of the fourth lens, the fifth lens, the sixth lens, and the seventh lens satisfies: 1.30≦f4567 / f≦1.48.

[0088] In this exemplary embodiment, the object side surface and the image side surface of any lens of the first lens E1 to the eighth lens E8 are both aspherical surfaces, and the surface shape x of each aspherical lens can be defined by, but not limited to, the following aspherical surface formula:

[0089]

[0090] Wherein, x is the distance vector height from the vertex of the aspheric surface when the aspheric surface is at a height of h along the optical axis; c is the paraxial curvature of the aspheric surface, c=1 / R (i.e., the paraxial curvature c is the reciprocal of the curvature radius R in Table 1); k is the cone coefficient; Ai is the correction coefficient of the i-th order aspheric surface.

[0091] In this exemplary embodiment, the optical imaging system may further include a stop. The stop may be disposed at an appropriate position as required, for example, the stop may be disposed between the object and the first lens. Optionally, the optical imaging system may further include a filter for correcting color deviation and / or a protective glass for protecting a photosensitive element located on the imaging surface.

[0092] The optical imaging system according to the above embodiment of the present invention can use multiple lenses, such as the above eight lenses. By reasonably allocating the focal length, surface shape, center thickness of each lens, and axial spacing between lenses, the optical imaging system has a larger imaging surface, a wide imaging range, and high imaging quality, and ensures the ultra-thinness of the mobile phone.

[0093] In an exemplary embodiment, at least one of the mirror surfaces of each lens is an aspherical mirror surface, that is, at least one of the mirror surfaces from the object side of the first lens to the image side of the eighth lens is an aspherical mirror surface. The characteristics of the aspherical lens are: the curvature changes continuously from the center of the lens to the periphery of the lens. Unlike the spherical lens with a constant curvature from the center of the lens to the periphery of the lens, the aspherical lens has a better curvature radius characteristic, and has the advantages of improving distortion aberration and improving astigmatism aberration. After adopting 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 and image side of each lens in 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 mirror surface. Optionally, the object side and image side of each lens in 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 all aspherical mirror surfaces.

[0094] However, those skilled in the art should understand that, without departing from the technical solution claimed in the present application, the number of lenses constituting the optical imaging system can be changed to obtain the various results and advantages described in this specification. For example, although eight lenses are used as an example in the embodiments, the optical imaging system is not limited to including eight lenses, and the optical imaging system may also include other numbers of lenses if necessary.

[0095] Specific embodiments of the optical imaging system applicable to the above embodiments are further described below with reference to the accompanying drawings. Specific embodiment 1

[0097] Figure 1 Schematic diagram of the lens group structure of embodiment 1 of the optical imaging system of the present invention. The optical imaging system includes, in order from the object side to the image side along the optical axis: an aperture STO, a first lens E1, a second lens E2, 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.

[0098] The first lens E1 has positive focal power, and its object side surface S1 is convex, and its image side surface S2 is concave. The second lens E2 has negative focal power, and its object side surface S3 is convex, and its image side surface S4 is concave. The third lens E3 has positive focal power, and its object side surface S5 is convex, and its image side surface S6 is concave. The fourth lens E4 has negative focal power, and its object side surface S7 is convex, and its image side surface S8 is concave. The fifth lens E5 has positive focal power, and its object side surface S9 is convex, and its image side surface S10 is convex. The sixth lens E6 has negative focal power, and its object side surface S11 is convex, and its image side surface S12 is concave. The seventh lens E7 has positive focal power, and its object side surface S13 is convex, and its image side surface S14 is concave. The eighth lens E8 has negative focal power, and its object side surface S15 is convex, and its image side surface S16 is concave. The filter E8 has an object-side surface S17 and an image-side surface S18. Light from the object passes through each of the surfaces S1 to S18 in sequence and is finally imaged on the imaging surface S19.

[0099] As shown in Table 1, it is a basic parameter table of the optical imaging system of Example 1, wherein the units of the radius of curvature, thickness, and focal length are all in millimeters (mm). The first lens E1 is preferably but not limited to GM material (molded glass), which has the characteristics of glass material and is easy to manufacture aspheric lenses, which is more conducive to optimization.

[0100]

[0101]

[0102] Table 1

[0103] As shown in Table 2, in Example 1, the total effective focal length f of the optical imaging system is 7.04 mm, the distance TTL on the optical axis from the object side surface S1 of the first lens E1 to the imaging surface S19 of the optical imaging system is 8.80 mm, and half of the diagonal length of the effective pixel area on the imaging surface S19 is ImgH=7.40 mm. Half of the maximum field angle Semi-FOV of the optical imaging system is 42.80°. The aperture value Fno of the optical imaging system is 1.68.

[0104]

[0105] Table 2

[0106] The optical imaging system in Example 1 satisfies:

[0107] TTL / ImgH=1.19; wherein TTL is the axial distance from the object side of the first lens to the imaging surface, and ImgH is half of the diagonal length of the effective pixel area on the imaging surface.

[0108] f7 / f×tan(Semi-FOV)=1.05; wherein f1 is the effective focal length of the first lens, f7 is the effective focal length of the seventh lens, and Semi-FOV is half of the maximum field of view of the optical imaging system.

[0109] (CT1+CT2+CT3-T34) / BFL=0.95; wherein 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, CT3 is the center thickness of the third lens on the optical axis, T34 is the air spacing between the third lens and the fourth lens on the optical axis, and BFL is the distance from the image side surface to the imaging surface of the last lens of the optical imaging system on the optical axis.

[0110] f7 / R13+f7 / R14=17.66; wherein R13 is the radius of curvature of the object side surface of the seventh lens, and R14 is the radius of curvature of the image side surface of the seventh lens.

[0111] |(R13+R14) / (R13-R14)|=2.35; wherein R13 is the radius of curvature of the object side surface of the seventh lens, and R14 is the radius of curvature of the image side surface of the seventh lens.

[0112] |f7 / f8|=1.40; wherein f7 is the effective focal length of the seventh lens, and f8 is the effective focal length of the eighth lens.

[0113] R3 / R4=1.52; wherein R3 is the radius of curvature of the object side of the second lens, and R4 is the radius of curvature of the image side of the second lens.

[0114] |(f5+f6) / f|=1.81; wherein f5 is the effective focal length of the fifth lens, f6 is the effective focal length of the sixth lens, and f is the effective focal length of the optical imaging system.

[0115] f234 / f=-2.93; wherein f234 is the combined focal length of the second lens, the third lens, and the fourth lens.

[0116] TTL / ΣAT=2.53; wherein TTL is the axial distance from the object side of the first lens to the imaging surface, and ΣAT is the sum of the air intervals on the optical axis between any two adjacent lenses with optical power from the first lens to the lens closest to the imaging surface.

[0117] |f4 / f1|=3.03; wherein f1 is the effective focal length of the first lens, and f4 is the effective focal length of the fourth lens.

[0118] SL / BFL=7.76; wherein SL is the on-axis distance from the aperture to the imaging plane, and BFL is the distance from the image side surface of the last lens of the optical imaging system to the imaging plane on the optical axis.

[0119] f4567 / f=1.36; wherein f4567 is the combined focal length of the fourth lens, the fifth lens, the sixth lens, and the seventh lens.

[0120] In Example 1, the object side surface and the image side surface of any lens from the first lens E1 to the eighth lens E8 are both aspherical surfaces. Table 3 shows the high-order coefficients A of the aspherical mirror surfaces S1-S16 that can be used in Example 1. 4 , A 6 , A 8 , A 10 , A 12 , A 14 , A 16 , A 18 , A 20 , A 22 , A 24 , A 26 , A 28 and A 30 .

[0121]

[0122]

[0123] Table 3

[0124] Figure 2a The axial chromatic aberration curve of the optical imaging system of Example 1 is shown, which indicates that light of different wavelengths deviates from the focal point behind the lens. Figure 2b FIG. 1 shows the astigmatism curve of the optical imaging system of Example 1, which represents the meridional image plane curvature and the sagittal image plane curvature. Figure 2a to Figure 2b It can be seen from the figure that the optical imaging system provided in Example 1 can achieve good imaging quality. Specific embodiment 2

[0126] Figure 3 Schematic diagram of the lens group structure of embodiment 2 of the optical imaging system of the present invention. The optical imaging system includes, in order from the object side to the image side along the optical axis: an aperture STO, a first lens E1, a second lens E2, 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.

[0127] The first lens E1 has positive focal power, and its object side surface S1 is convex, and its image side surface S2 is concave. The second lens E2 has negative focal power, and its object side surface S3 is convex, and its image side surface S4 is concave. The third lens E3 has positive focal power, and its object side surface S5 is convex, and its image side surface S6 is concave. The fourth lens E4 has negative focal power, and its object side surface S7 is convex, and its image side surface S8 is concave. The fifth lens E5 has positive focal power, and its object side surface S9 is convex, and its image side surface S10 is convex. The sixth lens E6 has negative focal power, and its object side surface S11 is convex, and its image side surface S12 is concave. The seventh lens E7 has positive focal power, and its object side surface S13 is convex, and its image side surface S14 is concave. The eighth lens E8 has negative focal power, and its object side surface S15 is convex, and its image side surface S16 is concave. The filter E8 has an object-side surface S17 and an image-side surface S18. Light from the object passes through each of the surfaces S1 to S18 in sequence and is finally imaged on the imaging surface S19.

[0128] As shown in Table 4, it is a basic parameter table of the optical imaging system of Example 2, wherein the units of the radius of curvature, thickness, and focal length are all in millimeters (mm). The first lens E1 is preferably but not limited to GM material (molded glass), which has the characteristics of glass material and is easy to manufacture aspheric lenses, which is more conducive to optimization.

[0129]

[0130] Table 4

[0131] As shown in Table 5, in Example 2, the total effective focal length of the optical imaging system is f=7.14 mm, the distance TTL on the optical axis from the object side surface S1 of the first lens E1 to the imaging surface S19 of the optical imaging system is 9.00 mm, and half of the diagonal length of the effective pixel area on the imaging surface S19 is ImgH=7.40 mm. Half of the maximum field angle of the optical imaging system is Semi-FOV=42.92°. The aperture value Fno of the optical imaging system is 1.68.

[0132]

[0133] Table 5

[0134] In Example 2, 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. Table 6 shows the high-order coefficients A of the aspherical mirror surfaces S1-S16 that can be used in Example 2. 4 , A 6 , A 8 , A 10 , A 12 , A 14 , A 16 , A 18 , A20 , A 22 , A 24 , A 26 , A 28 and A 30 .

[0135] Face number A4 A6 A8 A10 A12 A14 A16 S1 1.0610E-04 2.9349E-04 -3.3027E-04 2.1927E-04 -9.7344E-05 2.8261E-05 -5.3335E-06 S2 -7.3241E-03 3.5461E-03 -2.4165E-03 1.1571E-03 -3.3045E-04 5.2312E-05 -3.2204E-06 S3 -9.6543E-03 4.2420E-03 2.2134E-03 -9.9663E-03 1.4949E-02 -1.4277E-02 9.6807E-03 S4 -1.0451E-02 9.3839E-03 -1.8618E-02 4.0315E-02 -6.6276E-02 7.7556E-02 -6.4724E-02 S5 -1.2757E-02 2.7637E-03 -1.1028E-02 3.5411E-02 -7.3261E-02 9.7553E-02 -8.7619E-02 S6 -6.4024E-03 5.4501E-03 -2.1217E-02 4.4701E-02 -6.2081E-02 5.8353E-02 -3.7795E-02 S7 -2.2783E-02 -1.3423E-02 4.9517E-02 -1.0539E-01 1.4725E-01 -1.4493E-01 1.0343E-01 S8 -1.4143E-02 -2.9048E-02 6.7801E-02 -9.8817E-02 9.7416E-02 -6.8778E-02 3.5821E-02 S9 6.9210E-03 -3.0149E-02 5.0960E-02 -5.6469E-02 4.1504E-02 -2.0832E-02 7.3669E-03 S10 1.7064E-03 -1.0002E-02 7.6494E-03 -4.6130E-03 2.1311E-03 -7.1269E-04 1.6476E-04 S11 1.4768E-02 -1.8677E-02 1.5531E-02 -1.0169E-02 5.1175E-03 -1.9996E-03 6.0298E-04 S12 -2.0651E-02 -7.6965E-03 1.0540E-02 -5.9692E-03 2.2180E-03 -5.9895E-04 1.2148E-04 S13 -1.7956E-02 -2.4852E-04 1.0831E-03 -8.8034E-04 3.8187E-04 -1.0662E-04 2.0470E-05 S14 1.6686E-02 -3.7213E-03 -1.5289E-03 9.3393E-04 -2.5581E-04 4.5389E-05 -5.6728E-06 S15 -7.2708E-02 1.9297E-02 -4.1559E-03 6.6790E-04 -7.4031E-05 5.6561E-06 -3.0179E-07 S16 -7.9137E-02 2.3113E-02 -5.3430E-03 8.9631E-04 -1.0835E-04 9.4940E-06 -6.0682E-07 Face number A18 A20 A22 A24 A26 A28 A30 S1 5.8848E-07 -2.9169E-08 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S2 -1.7936E-07 2.4546E-08 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S3 -4.8001E-03 1.7443E-03 -4.5823E-04 8.4474E-05 -1.0342E-05 7.5371E-07 -2.4712E-08 S4 3.8823E-02 -1.6748E-02 5.1434E-03 -1.0959E-03 1.5382E-04 -1.2779E-05 4.7574E-07 S5 5.4695E-02 -2.4031E-02 7.4086E-03 -1.5693E-03 2.1752E-04 -1.7767E-05 6.4833E-07 S6 1.6909E-02 -5.1227E-03 9.8987E-04 -1.0165E-04 6.8016E-07 9.5395E-07 -6.9574E-08 S7 -5.4166E-02 2.0814E-02 -5.7986E-03 1.1389E-03 -1.4944E-04 1.1747E-05 -4.1796E-07 S8 -1.3882E-02 3.9818E-03 -8.3138E-04 1.2251E-04 -1.2053E-05 7.0989E-07 -1.8918E-08 S9 -1.8736E-03 3.4521E-04 -4.5771E-05 4.2621E-06 -2.6473E-07 9.8570E-09 -1.6678E-10 S10 -2.3327E-05 9.1910E-07 3.5813E-07 -8.0870E-08 7.9216E-09 -3.8418E-10 7.2666E-12 S11 -1.3847E-04 2.3796E-05 -2.9892E-06 2.6503E-07 -1.5650E-08 5.5075E-10 -8.7184E-12 S12 -1.8676E-05 2.1686E-06 -1.8683E-07 1.1522E-08 -4.7804E-10 1.1886E-11 -1.3324E-13 S13 -2.7807E-06 2.6939E-07 -1.8452E-08 8.7067E-10 -2.6864E-11 4.8711E-13 -3.9312E-15 S14 5.1367E-07 -3.3869E-08 1.6090E-09 -5.3572E-11 1.1848E-12 -1.5613E-14 9.2692E-17 S15 1.1276E-08 -2.8999E-10 4.8666E-12 -4.5734E-14 9.0627E-17 2.3682E-18 -1.6764E-20 S16 2.8374E-08 -9.6756E-10 2.3763E-11 -4.0907E-13 4.6832E-15 -3.2021E-17 9.8956E-20

[0136] Table 6

[0137] Figure 4a The axial chromatic aberration curve of the optical imaging system of Example 2 is shown, which indicates that light of different wavelengths deviates from the focal point behind the lens. Figure 4b FIG. 2 shows the astigmatism curve of the optical imaging system of Example 2, which represents the meridional image plane curvature and the sagittal image plane curvature. Figure 4a to Figure 4b It can be seen from the figure that the optical imaging system provided in Example 2 can achieve good imaging quality. Specific embodiment 3

[0139] Figure 5 Schematic diagram of the lens group structure of embodiment 3 of the optical imaging system of the present invention. The optical imaging system includes, in order from the object side to the image side along the optical axis: an aperture STO, a first lens E1, a second lens E2, 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.

[0140] The first lens E1 has positive focal power, and its object side surface S1 is convex, and its image side surface S2 is concave. The second lens E2 has negative focal power, and its object side surface S3 is convex, and its image side surface S4 is concave. The third lens E3 has positive focal power, and its object side surface S5 is convex, and its image side surface S6 is concave. The fourth lens E4 has negative focal power, and its object side surface S7 is convex, and its image side surface S8 is concave. The fifth lens E5 has positive focal power, and its object side surface S9 is convex, and its image side surface S10 is convex. The sixth lens E6 has negative focal power, and its object side surface S11 is convex, and its image side surface S12 is concave. The seventh lens E7 has positive focal power, and its object side surface S13 is convex, and its image side surface S14 is concave. The eighth lens E8 has negative focal power, and its object side surface S15 is convex, and its image side surface S16 is concave. The filter E8 has an object-side surface S17 and an image-side surface S18. Light from the object passes through each of the surfaces S1 to S18 in sequence and is finally imaged on the imaging surface S19.

[0141] As shown in Table 7, it is a basic parameter table of the optical imaging system of Example 3, wherein the units of the radius of curvature, thickness, and focal length are all in millimeters (mm). The first lens E1 is preferably but not limited to GM material (molded glass), which has the characteristics of glass material and is easy to manufacture aspheric lenses, which is more conducive to optimization.

[0142]

[0143] Table 7

[0144] As shown in Table 8, in Example 3, the total effective focal length f of the optical imaging system is 7.21 mm, the distance TTL on the optical axis from the object side surface S1 of the first lens E1 to the imaging surface S19 of the optical imaging system is 9.25 mm, and half of the diagonal length of the effective pixel area on the imaging surface S19 is ImgH=7.40 mm. Half of the maximum field angle Semi-FOV of the optical imaging system is 43.35°. The aperture value Fno of the optical imaging system is 1.68.

[0145]

[0146] Table 8

[0147] In Example 3, 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. Table 9 shows the high-order coefficients A of the aspherical mirror surfaces S1-S16 that can be used in Example 3. 4 , A 6 , A 8 , A 10 , A 12 , A 14 , A 16 , A 18 , A 20 , A 22 , A 24 , A 26 , A 28 and A 30 .

[0148]

[0149]

[0150] Table 9

[0151] Figure 6a The axial chromatic aberration curve of the optical imaging system of Example 3 is shown, which indicates that light of different wavelengths deviates from the focal point behind the lens. Figure 6b FIG. 3 shows the astigmatism curve of the optical imaging system of Example 3, which represents the meridional image plane curvature and the sagittal image plane curvature. Figure 6a to Figure 6b It can be seen from the figure that the optical imaging system provided in Example 3 can achieve good imaging quality. Specific embodiment 4

[0153] Figure 7Schematic diagram of the lens group structure of embodiment 4 of the optical imaging system of the present invention. The optical imaging system includes, in order from the object side to the image side along the optical axis: an aperture STO, a first lens E1, a second lens E2, 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.

[0154] The first lens E1 has positive focal power, and its object side surface S1 is convex, and its image side surface S2 is concave. The second lens E2 has negative focal power, and its object side surface S3 is convex, and its image side surface S4 is concave. The third lens E3 has positive focal power, and its object side surface S5 is convex, and its image side surface S6 is concave. The fourth lens E4 has negative focal power, and its object side surface S7 is convex, and its image side surface S8 is concave. The fifth lens E5 has positive focal power, and its object side surface S9 is convex, and its image side surface S10 is convex. The sixth lens E6 has negative focal power, and its object side surface S11 is convex, and its image side surface S12 is concave. The seventh lens E7 has positive focal power, and its object side surface S13 is convex, and its image side surface S14 is concave. The eighth lens E8 has negative focal power, and its object side surface S15 is convex, and its image side surface S16 is concave. The filter E8 has an object-side surface S17 and an image-side surface S18. Light from the object passes through each of the surfaces S1 to S18 in sequence and is finally imaged on the imaging surface S19.

[0155] As shown in Table 10, it is a basic parameter table of the optical imaging system of Example 4, wherein the units of the radius of curvature, thickness, and focal length are all in millimeters (mm). The first lens E1 is preferably but not limited to GM material (molded glass), which has the characteristics of glass material and is easy to manufacture aspheric lenses, which is more conducive to optimization.

[0156]

[0157]

[0158] Table 10

[0159] As shown in Table 11, in Example 4, the total effective focal length f of the optical imaging system is 7.45 mm, the distance TTL on the optical axis from the object side surface S1 of the first lens E1 to the imaging surface S19 of the optical imaging system is 9.25 mm, and half of the diagonal length of the effective pixel area on the imaging surface S19 is ImgH=7.40 mm. Half of the maximum field angle Semi-FOV of the optical imaging system is 43.33°. The aperture value Fno of the optical imaging system is 1.68.

[0160]

[0161] Table 11

[0162] In Example 4, 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. Table 12 shows the high-order coefficients A of the aspherical mirror surfaces S1-S16 that can be used in Example 4. 4 , A 6 , A 8 , A 10 , A 12 , A 14 , A 16 , A 18 , A 20 , A 22 , A 24 , A 26 , A 28 and A 30 .

[0163]

[0164]

[0165] Table 12

[0166] Figure 8a The axial chromatic aberration curve of the optical imaging system of Example 4 is shown, which indicates that light of different wavelengths deviates from the focal point behind the lens. Figure 8b The astigmatism curve of the optical imaging system of Example 4 is shown, which represents the meridional image plane curvature and the sagittal image plane curvature. Figure 8a to Figure 8b It can be seen from the figure that the optical imaging system provided in Example 4 can achieve good imaging quality. Specific embodiment 5

[0168] Fig. 9 Schematic diagram of the lens group structure of embodiment 5 of the optical imaging system of the present invention. The optical imaging system includes, in order from the object side to the image side along the optical axis: an aperture STO, a first lens E1, a second lens E2, 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.

[0169] The first lens E1 has positive focal power, and its object side surface S1 is convex, and its image side surface S2 is concave. The second lens E2 has negative focal power, and its object side surface S3 is convex, and its image side surface S4 is concave. The third lens E3 has positive focal power, and its object side surface S5 is convex, and its image side surface S6 is concave. The fourth lens E4 has negative focal power, and its object side surface S7 is convex, and its image side surface S8 is concave. The fifth lens E5 has positive focal power, and its object side surface S9 is convex, and its image side surface S10 is convex. The sixth lens E6 has negative focal power, and its object side surface S11 is convex, and its image side surface S12 is concave. The seventh lens E7 has positive focal power, and its object side surface S13 is convex, and its image side surface S14 is concave. The eighth lens E8 has negative focal power, and its object side surface S15 is convex, and its image side surface S16 is concave. The filter E8 has an object-side surface S17 and an image-side surface S18. Light from the object passes through each of the surfaces S1 to S18 in sequence and is finally imaged on the imaging surface S19.

[0170] As shown in Table 13, it is a basic parameter table of the optical imaging system of Example 5, wherein the units of the radius of curvature, thickness, and focal length are all in millimeters (mm). The first lens E1 is preferably but not limited to GM material (molded glass), which has the characteristics of glass material and is easy to manufacture aspheric lenses, which is more conducive to optimization.

[0171]

[0172] Table 13

[0173] As shown in Table 14, in Example 5, the total effective focal length f of the optical imaging system is 7.82 mm, the distance TTL on the optical axis from the object side surface S1 of the first lens E1 to the imaging surface S19 of the optical imaging system is 9.75 mm, and half of the diagonal length of the effective pixel area on the imaging surface S19 is ImgH=7.40 mm. Half of the maximum field angle Semi-FOV of the optical imaging system is 42.57°. The aperture value Fno of the optical imaging system is 1.68.

[0174]

[0175]

[0176] Table 14

[0177] In Example 5, 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. Table 15 shows the high-order coefficients A of the aspherical mirror surfaces S1 to S16 that can be used in Example 5. 4 , A 6 , A 8 , A 10 , A 12 , A14 , A 16 , A 18 , A 20 , A 22 , A 24 , A 26 , A 28 and A 30 .

[0178] Face number A4 A6 A8 A10 A12 A14 A16 S1 4.8527E-04 5.1334E-05 -1.7533E-04 2.1935E-04 -1.4128E-04 5.0868E-05 -1.0601E-05 S2 -7.7527E-03 4.5100E-03 -3.8126E-03 2.3357E-03 -9.2338E-04 2.3498E-04 -3.7076E-05 S3 -1.0262E-02 8.2305E-03 -1.0267E-02 1.2751E-02 -1.2696E-02 9.6427E-03 -5.4651E-03 S4 -8.7036E-03 5.6798E-03 -1.0717E-02 2.7833E-02 -5.3245E-02 6.8427E-02 -6.0117E-02 S5 -1.1716E-02 4.6286E-03 -1.6712E-02 3.9965E-02 -6.6318E-02 7.5863E-02 -6.1021E-02 S6 -5.6558E-03 8.2229E-04 -3.6226E-03 4.3295E-03 -2.5523E-03 -6.3414E-04 2.5494E-03 S7 -2.3666E-02 -7.2262E-03 3.1329E-02 -7.8091E-02 1.2621E-01 -1.4149E-01 1.1279E-01 S8 -1.4697E-02 -2.4763E-02 5.7755E-02 -8.5958E-02 8.7060E-02 -6.3185E-02 3.3782E-02 S9 4.9658E-03 -2.3816E-02 4.3219E-02 -5.1504E-02 4.0848E-02 -2.2311E-02 8.6810E-03 S10 -1.2800E-03 -7.7289E-03 1.0398E-02 -1.1499E-02 9.3390E-03 -5.4480E-03 2.2993E-03 S11 6.3992E-03 -6.8108E-03 4.0743E-03 -1.9483E-03 6.2102E-04 -1.3097E-04 1.8768E-05 S12 -1.7454E-02 -5.5956E-03 8.2656E-03 -4.8864E-03 1.8752E-03 -5.1767E-04 1.0617E-04 S13 -1.2973E-02 -5.6738E-03 4.2898E-03 -2.0411E-03 6.6979E-04 -1.5782E-04 2.7041E-05 S14 1.4843E-02 -8.3056E-03 1.6187E-03 -1.5695E-04 -9.4316E-06 5.9725E-06 -1.0503E-06 S15 -3.9074E-02 4.8594E-03 -4.2821E-04 4.3620E-05 -2.6738E-06 -1.0451E-07 3.3702E-08 S16 -4.0895E-02 7.7578E-03 -1.4664E-03 2.3161E-04 -2.7669E-05 2.4347E-06 -1.5741E-07 Face number A18 A20 A22 A24 A26 A28 A30 S1 1.1888E-06 -5.6353E-08 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S2 3.2812E-06 -1.2505E-07 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S3 2.3002E-03 -7.1638E-04 1.6323E-04 -2.6492E-05 2.9027E-06 -1.9240E-07 5.8203E-09 S4 3.6874E-02 -1.5941E-02 4.8351E-03 -1.0067E-03 1.3698E-04 -1.0965E-05 3.9142E-07 S5 3.5013E-02 -1.4380E-02 4.1906E-03 -8.4512E-04 1.1204E-04 -8.7765E-06 3.0756E-07 S6 -2.3489E-03 1.2658E-03 -4.4903E-04 1.0668E-04 -1.6423E-05 1.4849E-06 -5.9943E-08 S7 -6.4664E-02 2.6693E-02 -7.8540E-03 1.6054E-03 -2.1646E-04 1.7299E-05 -6.2032E-07 S8 -1.3410E-02 3.9308E-03 -8.3660E-04 1.2532E-04 -1.2499E-05 7.4373E-07 -1.9954E-08 S9 -2.4589E-03 5.1119E-04 -7.7529E-05 8.3784E-06 -6.1310E-07 2.7294E-08 -5.5915E-10 S10 -7.0611E-04 1.5751E-04 -2.5219E-05 2.8217E-06 -2.0937E-07 9.2536E-09 -1.8435E-10 S11 -2.3404E-06 4.2121E-07 -8.3822E-08 1.1550E-08 -9.6018E-10 4.3790E-11 -8.4532E-13 S12 -1.6298E-05 1.8621E-06 -1.5556E-07 9.1898E-09 -3.6209E-10 8.5081E-12 -8.9947E-14 S13 -3.3805E-06 3.0695E-07 -1.9947E-08 9.0071E-10 -2.6768E-11 4.6980E-13 -3.6843E-15 S14 1.1165E-07 -8.0107E-09 3.9702E-10 -1.3417E-11 2.9511E-13 -3.8037E-15 2.1758E-17 S15 -2.9614E-09 1.4996E-10 -4.9075E-12 1.0595E-13 -1.4649E-15 1.1800E-17 -4.2220E-20 S16 7.4840E-09 -2.6069E-10 6.5685E-12 -1.1651E-13 1.3802E-15 -9.8081E-18 3.1642E-20

[0179] Table 15

[0180] Fig.10a The axial chromatic aberration curve of the optical imaging system of Example 5 is shown, which indicates that light of different wavelengths deviates from the focal point behind the lens. Fig.10b The astigmatism curve of the optical imaging system of Example 5 is shown, which represents the meridional image plane curvature and the sagittal image plane curvature. Figure 10a to Figure 10b It can be seen from the figure that the optical imaging system provided in Example 5 can achieve good imaging quality. Specific embodiment 6

[0182] Fig.11 Schematic diagram of the lens group structure of embodiment 6 of the optical imaging system of the present invention. The optical imaging system includes, in order from the object side to the image side along the optical axis: an aperture STO, a first lens E1, a second lens E2, 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.

[0183] The first lens E1 has positive focal power, and its object side surface S1 is convex, and its image side surface S2 is concave. The second lens E2 has negative focal power, and its object side surface S3 is convex, and its image side surface S4 is concave. The third lens E3 has positive focal power, and its object side surface S5 is convex, and its image side surface S6 is concave. The fourth lens E4 has negative focal power, and its object side surface S7 is convex, and its image side surface S8 is concave. The fifth lens E5 has positive focal power, and its object side surface S9 is convex, and its image side surface S10 is convex. The sixth lens E6 has negative focal power, and its object side surface S11 is convex, and its image side surface S12 is concave. The seventh lens E7 has positive focal power, and its object side surface S13 is convex, and its image side surface S14 is concave. The eighth lens E8 has negative focal power, and its object side surface S15 is convex, and its image side surface S16 is concave. The filter E8 has an object-side surface S17 and an image-side surface S18. Light from the object passes through each of the surfaces S1 to S18 in sequence and is finally imaged on the imaging surface S19.

[0184] As shown in Table 16, it is a basic parameter table of the optical imaging system of Example 6, wherein the units of the radius of curvature, thickness, and focal length are all in millimeters (mm). The first lens E1 is preferably but not limited to GM material (molded glass), which has the characteristics of glass material and is easy to manufacture aspheric lenses, which is more conducive to optimization.

[0185]

[0186]

[0187] Table 16

[0188] As shown in Table 17, in Example 6, the total effective focal length f of the optical imaging system is 7.93 mm, the distance TTL on the optical axis from the object side surface S1 of the first lens E1 to the imaging surface S19 of the optical imaging system is 9.93 mm, and half of the diagonal length of the effective pixel area on the imaging surface S19 is ImgH=7.40 mm. Half of the maximum field angle Semi-FOV of the optical imaging system is 41.67°. The aperture value Fno of the optical imaging system is 1.68.

[0189]

[0190] Table 17

[0191] In Example 6, 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. Table 18 shows the high-order coefficients A of the aspherical mirror surfaces S1 to S16 that can be used in Example 6. 4 , A 6 , A 8 , A 10 , A 12 , A 14 , A 16 , A 18 , A 20 , A 22 , A 24 , A 26 , A 28 and A 30 .

[0192]

[0193]

[0194] Table 18

[0195] Fig.12a The axial chromatic aberration curve of the optical imaging system of Example 6 is shown, which indicates that light of different wavelengths deviates from the focal point behind the lens. Figure 12bThe astigmatism curve of the optical imaging system of Example 6 is shown, which represents the meridional image plane curvature and the sagittal image plane curvature. Figure 12a to Figure 12b It can be seen from the figure that the optical imaging system provided in Example 6 can achieve good imaging quality.

[0196] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, improvements, equivalent substitutions, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An optical imaging system, It is characterized in that The optical imaging system has eight lenses with optical power, and the eight lenses include, in order from the object side to the image side along the optical axis: The first lens has positive refractive power, the object side surface is convex, and the image side surface is concave; The second lens has a negative optical power, the object side surface is convex, and the image side surface is concave; The third lens has positive power, the object side surface is convex, and the image side surface is concave; The fourth lens element has a negative optical power, the object side surface is convex, and the image side surface is concave; A fifth lens having positive refractive power, a convex object-side surface and a convex image-side surface; The sixth lens element has a negative optical power, and its object side surface is convex and its image side surface is concave; The seventh lens has positive refractive power, the object side surface is convex, and the image side surface is concave; The eighth lens with negative optical power has a convex object-side surface and a concave image-side surface; The axial distance TTL from the object side of the first lens to the imaging surface and the half of the diagonal length of the effective pixel area on the imaging surface ImgH satisfy: 1.19≤TTL / ImgH≤1.34; The effective focal length f5 of the fifth lens, the effective focal length f6 of the sixth lens and the effective focal length f of the optical imaging system satisfy: 1.81≦|(f5+f6) / f|≦5.

61.

2. The optical imaging system according to claim 1, It is characterized in that The effective focal length f1 of the first lens, the effective focal length f7 of the seventh lens, and half of the maximum field of view Semi-FOV of the optical imaging system satisfy: 1.05≦f7 / f×tan(Semi-FOV)≦1.

2.

3. The optical imaging system according to claim 1, It is characterized in that The center thickness CT1 of the first lens on the optical axis, the center thickness CT2 of the second lens on the optical axis, the center thickness CT3 of the third lens on the optical axis, the air interval T34 between the third lens and the fourth lens on the optical axis, and the distance BFL from the image side surface to the imaging surface of the last lens of the optical imaging system on the optical axis satisfy: 0.76≦(CT1+CT2+CT3-T34) / BFL≦0.

95.

4. The optical imaging system according to claim 1, It is characterized in that A curvature radius R13 of the object side surface of the seventh lens and a curvature radius R14 of the image side surface of the seventh lens satisfy: 17.49≦f7 / R13+f7 / R14≦19.

25.

5. The optical imaging system according to claim 1, It is characterized in that A curvature radius R13 of the object-side surface of the seventh lens and a curvature radius R14 of the image-side surface of the seventh lens satisfy: 2.35≦|(R13+R14) / (R13-R14)|≦3.

36.

6. The optical imaging system according to claim 1, It is characterized in that The effective focal length f7 of the seventh lens and the effective focal length f8 of the eighth lens satisfy: 1.24≦|f7 / f8|≦1.

41.

7. The optical imaging system according to claim 1, It is characterized in that The curvature radius R3 of the object side surface of the second lens and the curvature radius R4 of the image side surface of the second lens satisfy: 1.5≦R3 / R4≦1.

63.

8. The optical imaging system according to claim 1, It is characterized in that The combined focal length f234 of the second lens, the third lens, and the fourth lens satisfies: -2.93≦f234 / f≦-2.

05.

9. The optical imaging system according to claim 1, It is characterized in that The axial distance TTL from the object side of the first lens to the imaging surface and the sum of the air intervals ΣAT on the optical axis between any two adjacent lenses with optical power from the first lens to the lens closest to the imaging surface satisfy: 2.53≦TTL / ΣAT≦2.

93.

10. The optical imaging system according to claim 1, It is characterized in that The effective focal length f1 of the first lens and the effective focal length f4 of the fourth lens satisfy: 2.3≦|f4 / f1|≦3.

03.

11. The optical imaging system according to claim 1, It is characterized in that The on-axis distance SL from the aperture to the imaging surface and the distance BFL from the image side surface of the last lens of the optical imaging system to the imaging surface on the optical axis satisfy: 6.86≦SL / BFL≦7.

76.

12. The optical imaging system according to claim 1, It is characterized in that The combined focal length f4567 of the fourth lens, the fifth lens, the sixth lens and the seventh lens satisfies: 1.36≦f4567 / f≦1.46.

Images