fixed focus lens

Abstract

The application discloses a fixed-focus lens, which comprises, in sequence from the object side to the image side along the optical axis, a first lens with negative refractive power, a second lens with refractive power, a third lens with refractive power, a fourth lens with positive refractive power, a fifth lens with positive refractive power, a sixth lens with positive refractive power, a seventh lens with negative refractive power, an eighth lens with positive refractive power, a ninth lens with negative refractive power, and a tenth lens with positive refractive power; wherein the combined focal length Fa of the sixth lens, the seventh lens and the eighth lens and the total effective focal length F of the fixed-focus lens satisfy: 1.8 ≤ Fa / F ≤ 4.5.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical elements, and more particularly to a fixed focus lens. BACKGROUND

[0002] With the increasing emphasis on the field of public security work, the market demand and requirements for security monitoring facilities such as security fixed focus lenses are also increasing.

[0003] Fixed focus lenses are widely used in various fields due to their high-definition imaging, clear imaging in low-illumination conditions, and other advantages. In order to meet the demand for higher image quality, large-sized photosensitive chips are required, which have more pixels, can capture more details, reduce noise, and improve imaging quality. In addition, in order to meet the requirements of large target surface and large aperture, larger and longer optical system size is often required. For example, the current market fixed focus lens that meets 1.0F aperture and 1 / 1.2" chip size usually has an optical total length of about 50mm, which is relatively large in volume.

[0004] Therefore, it is the current market demand to make such lenses have a smaller volume, and at the same time, the performance of the lenses in one or more aspects such as high resolution, large aperture, large target surface, low cost, and good thermal stability needs to be further improved. SUMMARY

[0005] The present application provides a fixed focus lens, which can include, in order from the object side to the image side along the optical axis, a first lens having negative refractive power, a second lens having refractive power, a third lens having refractive power, a fourth lens having positive refractive power, a fifth lens having positive refractive power, a sixth lens having positive refractive power, a seventh lens having negative refractive power, an eighth lens having positive refractive power, a ninth lens having negative refractive power, and a tenth lens having positive refractive power; wherein the combined focal length Fa of the sixth lens, the seventh lens and the eighth lens and the total effective focal length F of the fixed focus lens can satisfy: 1.8≤Fa / F≤4.5.

[0006] In one embodiment, the image side surface of the first lens can be concave; the object side surface of the second lens can be concave, and the image side surface can be convex; the object side surface of the fourth lens can be convex, and the image side surface can be convex; the image side surface of the fifth lens can be convex; the object side surface of the sixth lens can be convex, and the image side surface can be convex; the object side surface of the seventh lens can be concave, and the image side surface can be concave; the object side surface of the eighth lens can be convex, and the image side surface can be convex; the object side surface of the ninth lens can be concave, and the image side surface can be convex; the object side surface of the tenth lens can be convex, and the image side surface can be concave.

[0007] In one embodiment, the sixth lens, the seventh lens and the eighth lens can be a three-cemented lens group.

[0008] In an embodiment, the total effective focal length F of the fixed lens and the distance TTL from the center of the object side of the first lens to the imaging plane of the fixed lens on the optical axis can satisfy: 0.23≤F / TTL≤0.27.

[0009] In an embodiment, the distance TTL from the center of the object side of the first lens to the imaging plane of the fixed lens on the optical axis and the distance BFL from the center of the image side of the tenth lens to the imaging plane on the optical axis can satisfy: 5.9≤TTL / BFL≤6.3.

[0010] In an embodiment, the effective focal length F1 of the first lens and the total effective focal length F of the fixed lens can satisfy: -2.2≤F1 / F≤-1.5.

[0011] In an embodiment, the effective focal length F2 of the second lens and the total effective focal length F of the fixed lens can satisfy: -32.5≤F2 / F≤5.5.

[0012] In an embodiment, the air gap T12 of the first lens and the second lens on the optical axis and the distance TTL from the center of the object side of the first lens to the imaging plane of the fixed lens on the optical axis can satisfy: 0.08≤T12 / TTL≤0.15.

[0013] In an embodiment, the effective focal length F3 of the third lens and the total effective focal length F of the fixed lens can satisfy: -34.5≤F3 / F≤18.5.

[0014] In an embodiment, the refractive index ND2 of the second lens and the refractive index ND3 of the third lens can satisfy: 0.95≤ND2 / ND3≤1.05.

[0015] In an embodiment, the effective focal length F4 of the fourth lens and the total effective focal length F of the fixed lens can satisfy: 2.0≤F4 / F≤3.4.

[0016] In an embodiment, the effective focal length F5 of the fifth lens and the total effective focal length F of the fixed lens can satisfy: 2.3≤F5 / F≤6.5.

[0017] In an embodiment, the maximum optical full aperture value DM5 of the object side and the image side of the fifth lens and the distance TTL from the center of the object side of the first lens to the imaging plane of the fixed lens on the optical axis can satisfy: 0.38≤DM5 / TTL≤0.44.

[0018] In an embodiment, the effective focal length F6 of the sixth lens and the total effective focal length F of the fixed lens can satisfy: 1.15≤F6 / F≤1.75.

[0019] In one embodiment, the effective focal length F7 of the seventh lens and the total effective focal length F of the fixed focal length lens can satisfy: -1.1≤F7 / F≤-0.6.

[0020] In one embodiment, the effective focal length F8 of the eighth lens and the total effective focal length F of the fixed focal length lens can satisfy: 0.9≤F8 / F≤1.5.

[0021] In one embodiment, the sum da of the central thicknesses of the sixth lens, the seventh lens and the eighth lens on the optical axis and the distance TTL from the center of the object side of the first lens to the imaging surface of the fixed focal length lens on the optical axis can satisfy: 0.25≤da / TTL≤0.33.

[0022] In one embodiment, the effective focal length F9 of the ninth lens and the total effective focal length F of the fixed focal length lens can satisfy: -4.5≤F9 / F≤-1.5.

[0023] In one embodiment, the effective focal length F10 of the tenth lens and the total effective focal length F of the fixed focal length lens can satisfy: 1.9≤F10 / F≤5.8.

[0024] In one embodiment, the effective focal length F9 of the ninth lens and the effective focal length F10 of the tenth lens can satisfy: -1.35≤F9 / F10≤-0.6.

[0025] In one embodiment, the radius of curvature R101 of the object side of the tenth lens and the radius of curvature R102 of the image side of the tenth lens can satisfy: -29≤(R101+R102) / (R101-R102)≤-3.

[0026] In one embodiment, the entrance pupil diameter ENPD of the fixed focal length lens and the total effective focal length F of the fixed focal length lens can satisfy: 0.85≤ENPD / F≤0.98.

[0027] The fixed focal length lens of the present application comprises first to tenth lenses arranged in order from the object side to the image side along the optical axis, by setting the first lens to have negative refractive power, the fourth, fifth and sixth lenses to each have positive refractive power, the seventh lens to have negative refractive power, the eighth lens to have positive refractive power, the ninth lens to have negative refractive power, and the tenth lens to have positive refractive power, and controlling the combined focal length Fa of the sixth lens, the seventh lens and the eighth lens and the total effective focal length F of the fixed focal length lens to satisfy the condition 1.8≤Fa / F≤4.5, the system chromatic aberration can be effectively reduced and the system spherical aberration can be effectively balanced, the resolution can be improved, 4K high resolution can be realized, and at the same time the tolerance sensitivity between the lenses can be reduced, which is conducive to improving the production yield.

[0028] The fixed focus lens of the present application adopts ten lenses. By reasonably setting some of the parameters such as refractive power, surface type, curvature radius, and refractive index of the lenses, the lens can have at least one of the beneficial effects of 4K high resolution, large aperture (for example, FNO≤1.12), large target surface (for example, full image height H≥12.9mm), low cost, small size (for example, TTL≤30.2mm), and clear imaging in an environment of, for example, -40℃ to +80℃. BRIEF DESCRIPTION OF DRAWINGS

[0029] Other features, objects, and advantages of the present application will become more apparent from the following detailed description of the embodiments, when read in conjunction with the accompanying drawings. In the drawings:

[0030] Figure 1 is a structural schematic diagram of a fixed focus lens according to Embodiment 1 of the present application;

[0031] Figure 2 is a structural schematic diagram of a fixed focus lens according to Embodiment 2 of the present application;

[0032] Figure 3 is a structural schematic diagram of a fixed focus lens according to Embodiment 3 of the present application; and

[0033] Figure 4 is a structural schematic diagram of a fixed focus lens according to Embodiment 4 of the present application. DETAILED DESCRIPTION

[0034] For the purpose of promoting an understanding of the present application, the present application will now be described in greater detail with reference to the relevant drawings. It is to be understood that these detailed descriptions are merely illustrative of exemplary embodiments of the present application and do not limit the scope of the present application in any way. Throughout this 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.

[0035] It should be noted that, in the present specification, the expressions first, second, third, and the like are merely used to distinguish one feature from another feature, and do not represent any limitation on the features. Thus, the first lens discussed below can also be referred to as the second lens or the third lens without departing from the teachings of the present application.

[0036] In the drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for the purpose of illustration. Specifically, the shape of the spherical surface or the aspherical surface shown in the drawings is shown by way of example. That is, the shape of the spherical surface or the aspherical surface is not limited to the shape of the spherical surface or the aspherical surface shown in the drawings. The drawings are merely examples and are not drawn strictly to scale.

[0037] In the present disclosure, 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 imaging side is referred to as the image side surface of the lens.

[0038] It should also be understood that the words "comprise," "comprising," "include," "including," and / or "has," "having," when used in the present 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. In addition, when terms such as "at least one of," "one or more of," or "one or more" are used in the present description, they represent an inclusion of at least one of a number of items, items, components or components, and that the number of items, items, components or components is one or more. In addition, when describing implementations of the present application, the word "can" means "one or more implementations of the present application." Also, the word "exemplary" is intended to mean an example or an illustration.

[0039] 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 should also be understood that the terms 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 idealized or overly formal sense unless expressly so defined herein.

[0040] 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.

[0041] The features, principles, and other aspects of the present application are described in detail below.

[0042] In exemplary embodiments, a fixed focal length lens according to the present application can include, for example, ten lenses having optical power, i.e., a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, and a tenth lens. The ten lenses can be arranged in order along the optical axis from the object side to the image side.

[0043] In an exemplary embodiment, the first lens can have a negative optical power; the second lens can have a positive optical power or a negative optical power; the third lens can have a positive optical power or a negative optical power; the fourth lens can have a positive optical power; the fifth lens can have a positive optical power; the sixth lens can have a positive optical power; the seventh lens can have a negative optical power; the eighth lens can have a positive optical power; the ninth lens can have a negative optical power; and the tenth lens can have a positive optical power.

[0044] In an exemplary embodiment, the first lens can have a negative optical power. The image-side surface of the first lens can be a concave surface. With such an arrangement, the first lens can diverge the large field of view light rays entering the optical system to the rear optical system, which can effectively increase the light throughput and improve the resolution.

[0045] In an exemplary embodiment, the second lens can have a concave-convex surface shape, which can gently the angle of the light rays passing through the second lens, correct aberrations, and improve the lens resolution.

[0046] In an exemplary embodiment, the third lens can be located next to the diaphragm, which can balance the aberrations generated by the light rays passing through the diaphragm and ensure the image quality. For example, the diaphragm can be located between the second lens and the third lens.

[0047] In an exemplary embodiment, the fourth lens can have a positive optical power. The fourth lens can have a convex-convex surface shape. By arranging the fourth lens to have a positive optical power and a convex image-side surface, the light ray trend can be gently controlled, which is conducive to achieving a small lens size.

[0048] In an exemplary embodiment, the fifth lens can have a positive optical power. The image-side surface of the fifth lens can be a convex surface. With such an arrangement of the fifth lens, the light ray trend can be further controlled, which is conducive to achieving high image quality under a large target surface. Meanwhile, the material of the fifth lens can be glass, which is conducive to balancing the high and low temperature performance.

[0049] In an exemplary embodiment, the sixth lens can have a positive optical power. The sixth lens can have a convex-convex surface shape. With such an arrangement of the sixth lens, the system field curvature can be balanced, which is conducive to achieving high image quality. For example, the sixth lens, the seventh lens having a negative optical power and a concave-concave lens shape, and the eighth lens having a positive optical power and a convex-convex lens shape can be cemented to form a three-cemented lens group, which can effectively balance various aberrations, improve the resolution, and achieve 4K high resolution. Meanwhile, the tolerance sensitivity between the lenses can be reduced, which is conducive to improving the production yield.

[0050] In an exemplary embodiment, the seventh lens can have a negative refractive power. The seventh lens can have a concave-concave shape. The seventh lens with a negative refractive power and a concave-concave shape can be used in combination with the sixth lens with a positive refractive power and a convex-convex shape to balance the spherical aberration of the system, improve the resolution, and achieve high resolution.

[0051] In an exemplary embodiment, the eighth lens can have a positive refractive power. The eighth lens can have a convex-convex shape. The eighth lens with a positive refractive power and a convex-convex shape can be used in combination with the seventh lens with a negative refractive power and a concave-concave shape to balance the astigmatism generated by the light passing through the system and facilitate the guarantee of the image quality under a large target surface.

[0052] In an exemplary embodiment, the ninth lens can have a negative refractive power. The ninth lens can have a concave-convex shape. The arrangement of the ninth lens with a negative refractive power and a concave-convex shape can be used in cooperation with the positive lens (for example, the tenth lens with a positive refractive power) at the rear end to balance the aberration of the system as a whole and improve the resolving power.

[0053] In an exemplary embodiment, the tenth lens can have a positive refractive power. The tenth lens can have a convex-concave shape. The tenth lens with a positive refractive power can guarantee the height of the light at the rear end and facilitate the realization of a large target surface.

[0054] In an exemplary embodiment, the fixed-focus lens according to the present application can include a diaphragm. The diaphragm can be located, for example, between the second lens and the third lens, can effectively converge the light entering the optical system, shorten the total length of the optical system, reduce the maximum light aperture of the optical system, and facilitate the realization of miniaturization design. It should be noted that the position of the diaphragm disclosed herein is only an example and is not a limitation; in alternative embodiments, the diaphragm can also be arranged at other positions according to actual needs.

[0055] In an exemplary embodiment, the fixed-focus lens can further include a photosensitive element arranged at the imaging surface. Optionally, the photosensitive element arranged at the imaging surface can be, for example, a charge-coupled device (CCD) or a complementary metal-oxide-semiconductor (CMOS).

[0056] In an exemplary embodiment, the object side and the image side of each of the first lens to the tenth lens included in the fixed-focus lens can have an aspheric mirror surface. For example, in one embodiment, the object side and the image side of the first lens, the object side and the image side of the second lens, the object side and the image side of the third lens, the object side and the image side of the fourth lens, the object side and the image side of the ninth lens, and the object side and the image side of the tenth lens can be aspheric mirror surfaces.

[0057] In an exemplary embodiment, at least one inflection point can be present on the object side and the image side of the ninth lens and on the object side and the image side of the tenth lens.

[0058] In the example embodiment, the fixed focus lens can adopt a glass-plastic hybrid material. The adoption of the glass-plastic hybrid material for the lenses in the lens can be conducive to reducing the cost of the optical system, balancing the high and low temperature performance of the optical lens, and enabling the lens to achieve a high imaging quality in a range of, for example, -40°C to +80°C.

[0059] In the example embodiment, the sixth lens, the seventh lens, and the eighth lens can be a three-cemented lens group that are cemented with each other. Various aberrations can be balanced, the resolution can be improved, and 4K high resolution can be achieved. Meanwhile, the tolerance sensitivity between the lenses can be reduced, which is conducive to ensuring the production yield.

[0060] In the example embodiment, the F-number FNO of the fixed focus lens according to the present application can satisfy, for example, FNO≤1.12. The optical lens can be ensured to have a large aperture characteristic.

[0061] In the example embodiment, the total image height H of the fixed focus lens according to the present application can satisfy, for example, H≥12.9mm. The lens has a large target surface, which is conducive to having high optical performance and matching the optical lens with sensors of different specifications.

[0062] In the example embodiment, the total optical length of the fixed focus lens according to the present application, that is, the distance TTL on the optical axis from the center of the object side of the first lens to the imaging surface of the fixed focus lens can satisfy, for example, TTL≤30.2mm. The total length of the lens is relatively short, the structure is compact, and miniaturization can be achieved.

[0063] The fixed focus lens according to the example embodiment of the present application includes first to tenth lenses arranged in order along the optical axis from the object side to the image side. By setting the first lens to have a negative focal power, the fourth, fifth, and sixth lenses to have a positive focal power, the seventh lens to have a negative focal power, the eighth lens to have a positive focal power, the ninth lens to have a negative focal power, and the tenth lens to have a positive focal power, and controlling the combined focal length Fa of the sixth lens, the seventh lens, and the eighth lens and the total effective focal length F of the fixed focus lens to satisfy the condition formula 1.8≤Fa / F≤4.5, the chromatic aberration of the system can be effectively reduced, the spherical aberration of the system can be effectively balanced, the resolution can be improved, and 4K high resolution can be achieved. Meanwhile, the tolerance sensitivity between the lenses can be reduced, which is conducive to improving the production yield.

[0064] The fixed focus lens according to the exemplary embodiments of the present application adopts ten lenses, and by reasonably setting some of the parameters such as the refractive power, surface type, curvature radius, and refractive index of the lenses, the lens can have at least one of the beneficial effects of 4K high resolution, large aperture (for example, FNO≤1.12), large target surface (for example, full image height H≥12.9 mm), low cost, small size (for example, TTL≤30.2 mm), and clear imaging in an environment of, for example, -40°C to +80°C.

[0065] In the exemplary embodiments, the fixed focus lens according to the present application can satisfy 0.23≤F / TTL≤0.27, where F is the total effective focal length of the fixed focus lens, and TTL is the distance from the center of the object side surface of the first lens to the imaging surface of the fixed focus lens on the optical axis. Controlling the ratio of the two within the range, in the case of a certain system focal length value, the system optical total length is reasonably controlled to be small, which is beneficial to realize the small size of the system.

[0066] In the exemplary embodiments, the fixed focus lens according to the present application can satisfy 5.9≤TTL / BFL≤6.3, where TTL is the distance from the center of the object side surface of the first lens to the imaging surface of the fixed focus lens on the optical axis, and BFL is the distance from the center of the image side surface of the tenth lens to the imaging surface on the optical axis. Controlling the ratio of the two within the range, on the basis of miniaturization, by controlling the length of the system optical back focal BFL, the back focal length of the lens is longer, which helps to reserve space for the installation of optical elements, facilitates the assembly of the optical lens, avoids interference, and is beneficial to improve the assembly yield of the optical lens.

[0067] In the exemplary embodiments, the fixed focus lens according to the present application can satisfy -2.2≤F1 / F≤-1.5, where F1 is the effective focal length of the first lens, and F is the total effective focal length of the fixed focus lens. By reasonably controlling the ratio of the effective focal length of the first lens to the total effective focal length of the fixed focus lens within the range, the incident light can be effectively converged, the large field of view light entering the optical system can be diverged to the rear of the optical system, the light quantity can be effectively increased, the illumination can be improved, and the field of view angle can be effectively expanded.

[0068] In the exemplary embodiments, the fixed focus lens according to the present application can satisfy -32.5≤F2 / F≤5.5, where F2 is the effective focal length of the second lens, and F is the total effective focal length of the fixed focus lens. By reasonably controlling the ratio of the effective focal length of the second lens to the total effective focal length of the fixed focus lens within the range, the light transition can be smooth, the sensitivity of the first lens can be reduced, the aberration can be corrected, the resolution of the lens can be improved, and the aperture can be increased to satisfy, for example, FNO≤1.12. More specifically, F2 and F can further satisfy -32.5≤F2 / F≤3.5.

[0069] In exemplary embodiments, the fixed focus lens according to the present application can satisfy: 0.08≤T12 / TTL≤0.15, where T12 is the air interval of the first lens and the second lens on the optical axis, and TTL is the distance from the center of the object side surface of the first lens to the imaging surface of the fixed focus lens on the optical axis. By controlling the ratio of the two within the range, it is beneficial to maintain a suitable air interval between the first lens and the second lens, reduce the aberration generated at the front end of the lens, and achieve high image quality.

[0070] In exemplary embodiments, the fixed focus lens according to the present application can satisfy: -34.5≤F3 / F≤18.5, where F3 is the effective focal length of the third lens, and F is the total effective focal length of the fixed focus lens. By controlling the ratio of the two within the range, the aberration generated when the light passes through the diaphragm can be balanced to ensure image quality, and the aperture can be increased to satisfy, for example, FNO≤1.12.

[0071] In exemplary embodiments, the fixed focus lens according to the present application can satisfy: 0.95≤ND2 / ND3≤1.05, where ND2 is the refractive index of the second lens, and ND3 is the refractive index of the third lens. By controlling the ratio of the two within the range, the aberration generated when the light passes through the diaphragm can be reduced to facilitate clear imaging of the lens.

[0072] In exemplary embodiments, the fixed focus lens according to the present application can satisfy: 2.0≤F4 / F≤3.4, where F4 is the effective focal length of the fourth lens, and F is the total effective focal length of the fixed focus lens. By controlling the ratio of the two within the range, the astigmatism can be corrected while effectively converging the light, which is beneficial to achieving a small volume and high image quality of the lens.

[0073] In exemplary embodiments, the fixed focus lens according to the present application can satisfy: 2.3≤F5 / F≤6.5, where F5 is the effective focal length of the fifth lens, and F is the total effective focal length of the fixed focus lens. By controlling the ratio of the two within the range, the light path can be further controlled, which is beneficial to achieving high image quality under a large target surface, and the effective focal length of the fifth lens can be kept stable within a large temperature range, which is beneficial to balancing the high and low temperature performance.

[0074] In exemplary embodiments, the fixed focus lens according to the present application can satisfy: 0.38≤DM5 / TTL≤0.44, where DM5 is the maximum optical full aperture value of the object side surface and the image side surface of the fifth lens, and TTL is the distance from the center of the object side surface of the first lens to the imaging surface of the fixed focus lens on the optical axis. By controlling the ratio of the two within the range, the volume of the system can be reduced, which is beneficial to the miniaturization of the lens.

[0075] In an example embodiment, the fixed focus lens according to the present application can satisfy: 1.15≤F6 / F≤1.75, where F6 is the effective focal length of the sixth lens, and F is the total effective focal length of the fixed focus lens. By controlling the ratio of the two within the range, the focal length value of the sixth lens is reasonably set to cooperate with the focal length value of the seventh lens, effectively balancing the system field curvature, improving resolution, and achieving high resolution.

[0076] In an example embodiment, the fixed focus lens according to the present application can satisfy: -1.1≤F7 / F≤-0.6, where F7 is the effective focal length of the seventh lens, and F is the total effective focal length of the fixed focus lens. By controlling the ratio of the two within the range, the focal length value of the seventh lens is reasonably set to cooperate with the focal length values of the sixth lens and the eighth lens, effectively balancing the system spherical aberration, improving resolution, and achieving high resolution.

[0077] In an example embodiment, the fixed focus lens according to the present application can satisfy: 0.9≤F8 / F≤1.5, where F8 is the effective focal length of the eighth lens, and F is the total effective focal length of the fixed focus lens. By controlling the ratio of the two within the range, the focal length value of the eighth lens is reasonably set to cooperate with the focal length value of the seventh lens, which can balance the astigmatism generated by the light passing through the system, and is conducive to ensuring the image quality under a large target surface.

[0078] In an example embodiment, the fixed focus lens according to the present application can satisfy: 1.8≤Fa / F≤4.5, where Fa is the combined focal length of the sixth lens, the seventh lens and the eighth lens, and F is the total effective focal length of the fixed focus lens. For example, the sixth lens, the seventh lens and the eighth lens can be glued to form a three-glued lens group, and Fa can be the effective focal length of the three-glued lens group. By reasonably controlling the ratio of the focal length of the glued lens to the effective focal length of the optical system, the system chromatic aberration and the system spherical aberration can be effectively reduced, the resolution can be improved, and 4K high resolution can be achieved; at the same time, the tolerance sensitivity between the lenses can be reduced, which is conducive to improving the production yield.

[0079] In an example embodiment, the fixed focus lens according to the present application can satisfy: 0.25≤da / TTL≤0.33, where da is the sum of the central thicknesses of the sixth lens, the seventh lens and the eighth lens on the optical axis, and TTL is the distance from the center of the object side of the first lens to the imaging surface of the fixed focus lens on the optical axis. By controlling the ratio of the two within the range, the thickness value of the glued lens can be reasonably distributed, which can balance the system aberration while reducing the material cost caused by the thickness, and is conducive to achieving low cost.

[0080] In exemplary embodiments, the fixed focus lens according to the present application can satisfy: -4.5≤F9 / F≤-1.5, where F9 is the effective focal length of the ninth lens, and F is the total effective focal length of the fixed focus lens. By controlling the ratio of the two within this range, the light path can be effectively controlled, the light can be smoothly transitioned, the off-axis aberration can be effectively balanced, and the image quality under a large target surface can be ensured. More specifically, F9 and F can further satisfy: -4.5≤F9 / F≤-2.5.

[0081] In exemplary embodiments, the fixed focus lens according to the present application can satisfy: 1.9≤F10 / F≤5.8, where F10 is the effective focal length of the tenth lens, and F is the total effective focal length of the fixed focus lens. By controlling the ratio of the two within this range, the light path can be effectively controlled, the light height can be ensured, the light can be quickly focused to the imaging surface, a large target surface can be implemented, and the full image height H can satisfy H≥12.9mm. More specifically, F10 and F can further satisfy: 2.9≤F10 / F≤5.8.

[0082] In exemplary embodiments, the fixed focus lens according to the present application can satisfy: -1.35≤F9 / F10≤-0.6, where F9 is the effective focal length of the ninth lens, and F10 is the effective focal length of the tenth lens. By controlling the ratio of the two within this range, the focal length values of the ninth lens and the tenth lens can be reasonably distributed, the positive and negative lenses can be used in cooperation, the optical aberration converging to the receiving chip can be reduced, and high resolution can be achieved.

[0083] In exemplary embodiments, the fixed focus lens according to the present application can satisfy: -29≤(R101+R102) / (R101-R102)≤-3, where R101 is the curvature radius of the object side surface of the tenth lens, and R102 is the curvature radius of the image side surface of the tenth lens. By controlling the curvature radii of the object side surface and the image side surface of the tenth lens to satisfy this condition, the balance of the system coma can be facilitated, the edge field image quality of the large target surface can be ensured, and the lens quality can be improved. More specifically, R101 and R102 can further satisfy: -29≤(R101+R102) / (R101-R102)≤-8.

[0084] In exemplary embodiments, the fixed focus lens according to the present application can satisfy: 0.85≤ENPD / F≤0.98, where ENPD is the entrance pupil diameter of the fixed focus lens, and F is the total effective focal length of the fixed focus lens. By controlling the ratio of the two within this range, the system can have a smaller aperture value, a large aperture can be implemented, and FNO≤1.12 can be satisfied.

[0085] In exemplary embodiments, the fixed focal length lens of the present application can further include a filter and / or a protective glass disposed between the tenth lens and the image plane, as needed. The filter can filter light having a specific wavelength, and the protective glass can prevent damage to the image-side elements (e.g., a chip) of the fixed focal length lens.

[0086] The fixed focal length lens according to the embodiments of the present application can employ multiple lenses, for example, ten lenses as described above. By properly setting, for example, some of the parameters of the refractive power, the surface shape, the radius of curvature, and the refractive index of each lens, the lens can have at least one of the beneficial effects, for example, 4K high resolution, a large aperture (e.g., FNO≤1.12), a large target surface (e.g., full image height H≥12.9 mm), low cost, small size (e.g., TTL≤30.2 mm), and clear imaging in an environment of, for example, -40°C to +80°C.

[0087] However, those skilled in the art will understand that the number of lenses constituting the lens 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 ten lenses are described as an example in the embodiments, the fixed focal length lens is not limited to including ten lenses. If needed, the fixed focal length lens can further include other numbers of lenses. Specific embodiments of the fixed focal length lens applicable to the above-described embodiments are further described below with reference to the accompanying drawings.

[0088] Example 1

[0089] Figure 1 is a structural schematic diagram of the fixed focal length lens according to Embodiment 1 of the present application, and the fixed focal length lens according to Embodiment 1 of the present application is described below with reference to Figure 1

[0090] As shown in Figure 1 , the fixed focal length lens includes, in order from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a stop STO, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9, a tenth lens L10, a filter and / or a protective glass PB, and an image plane (IMA). Among them, the sixth lens L6, the seventh lens L7, and the eighth lens L8 are cemented to form a three-cemented lens group.

[0091] ​In this embodiment, the first lens L1 has negative refractive power, the object side S1 is convex, and the image side S2 is concave. The second lens L2 has negative refractive power, the object side S3 is concave, and the image side S4 is convex. The third lens L3 has positive refractive power, the object side S6 is convex, and the image side S7 is concave. The fourth lens L4 has positive refractive power, the object side S8 is convex, and the image side S9 is convex. The fifth lens L5 has positive refractive power, the object side S10 is concave, and the image side S11 is convex. The sixth lens L6 has positive refractive power, the object side S12 is convex, and the image side S13 is convex. The seventh lens L7 has negative refractive power, the object side S13 is concave, and the image side S14 is concave. The eighth lens L8 has positive refractive power, the object side S14 is convex, and the image side S15 is convex. The ninth lens L9 has negative refractive power, the object side S16 is concave, and the image side S17 is convex. The tenth lens L10 has positive refractive power, the object side S18 is convex, and the image side S19 is concave.

[0092] In this embodiment, the stop STO of the fixed focus lens is arranged between the second lens L2 and the third lens L3.

[0093] In this embodiment, the filter and / or protective glass PB between the tenth lens L10 and the imaging surface has an object side S20 and an image side S21. Light from the object can pass through the surfaces S1 to S21 in sequence and finally be imaged on the imaging surface S22, for example, where an image sensor chip IMA can be arranged, for example.

[0094] Table 1 shows the radius of curvature R, the thickness d / distance T, the refractive index ND, and the Abbe number Vd of each lens of the fixed focus lens of embodiment 1. Where the "thickness d / distance T" is concerned, it is understood that the thickness d / distance T of the row in which S1 is located is the central thickness of the first lens L1, the thickness d / distance T of the row in which S2 is located is the air gap between the first lens L1 and the second lens L2, the thickness d / distance T of the row in which S3 is located is the central thickness of the second lens L2, and so on.

[0095]

[0096]

[0097] Table 1

[0098] In this embodiment, the fixed focus lens has an aperture number FNO = 1.10, a total image height H = 13.54 mm, and an overall optical length TTL = 30.15 mm.

[0099] In this embodiment, the object-side and image-side surfaces of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the ninth lens L9, and the tenth lens L10 are all aspherical. The surface shape x of each aspherical lens can be defined using, but is not limited to, the following aspherical formula:

[0100]

[0101] Where x is the distance vector from the vertex of the aspherical surface at a height h along the optical axis; c is the paraxial curvature of the aspherical surface, c = 1 / R (i.e., the paraxial curvature c is the reciprocal of the radius of curvature R in Table 1 above); k is the conic coefficient; Ai is the i-th order correction coefficient of the aspherical surface. Table 2 below gives the conic coefficient k and higher-order coefficients A4, A6, A8, A19 that can be used for each aspherical mirror S1-S4, S6-S9, S16-S19 in Example 1. 10 A 12 and A 14 .

[0102] Face No. k A4 A6 A8 A10 A12 A14 S1 -55.60 -1.31E-04 -3.96E-06 4.08E-07 -1.26E-08 2.08E-10 -1.20E-12 S2 0.02 -1.58E-04 -1.68E-06 -6.74E-07 7.03E-08 -3.31E-09 5.91E-11 S3 -3.63 -3.36E-04 -5.83E-05 4.38E-06 -1.54E-07 2.15E-09 7.26E-12 S4 -5.11 -5.51E-04 1.13E-05 2.82E-08 6.63E-09 -1.85E-10 3.11E-12 S6 -11.05 -1.18E-04 1.43E-06 3.39E-08 1.43E-09 3.33E-11 -5.86E-13 S7 -24.63 -4.10E-04 1.68E-06 8.37E-08 1.18E-09 9.47E-11 -1.66E-12 S8 99.73 -1.89E-04 -2.48E-06 5.66E-08 3.05E-09 1.63E-11 -1.68E-12 S9 -0.12 4.29E-05 -6.40E-07 -2.98E-08 2.75E-09 -5.39E-11 5.51E-14 S16 -10.80 7.13E-04 -5.71E-06 -2.47E-07 7.18E-09 -1.11E-10 1.65E-12 S17 -7.72 1.18E-03 -2.80E-05 4.98E-07 -2.28E-09 -2.89E-10 6.28E-12 S18 -8.37 -8.63E-04 -6.22E-05 2.69E-06 -7.94E-08 1.02E-09 -2.58E-12 S19 -5.77 -1.02E-03 -1.13E-05 2.82E-07 -4.88E-09 7.78E-11 -4.31E-13

[0103] Table 2

[0104] Example 2

[0105] Figure 2 A schematic diagram of the fixed-focus lens according to Embodiment 2 of this application is shown below, with reference to the following. Figure 2 This application describes a fixed-focus lens according to Embodiment 2. For the sake of brevity, descriptions similar to those in Embodiment 1 will be omitted in this embodiment and the following embodiments.

[0106] like Figure 2 As shown, the fixed-focus lens, along the optical axis from the object side to the image side, includes, in sequence: a first lens L1, a second lens L2, an aperture stop STO, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9, a tenth lens L10, a filter and / or protective glass PB, and an imaging plane (IMA). The sixth lens L6, the seventh lens L7, and the eighth lens L8 are cemented together to form a cemented triplet lens group.

[0107] In this embodiment, the first lens L1 has negative optical power, its object-side surface S1 is convex, and its image-side surface S2 is concave. The second lens L2 has negative optical power, its object-side surface S3 is concave, and its image-side surface S4 is convex. The third lens L3 has negative optical power, its object-side surface S6 is convex, and its image-side surface S7 is concave. The fourth lens L4 has positive optical power, its object-side surface S8 is convex, and its image-side surface S9 is convex. The fifth lens L5 has positive optical power, its object-side surface S10 is flat, and its image-side surface S11 is convex. The sixth lens L6 has positive optical power, its object-side surface S12 is convex, and its image-side surface S13 is convex. The seventh lens L7 has negative optical power, its object-side surface S13 is concave, and its image-side surface S14 is concave. The eighth lens L8 has positive optical power, its object-side surface S14 is convex, and its image-side surface S15 is convex. The ninth lens L9 has negative optical power, with its object-side surface S16 being concave and its image-side surface S17 being convex. The tenth lens L10 has positive optical power, with its object-side surface S18 being convex and its image-side surface S19 being concave.

[0108] In this embodiment, the aperture stop STO of the fixed-focus lens is positioned between the second lens L2 and the third lens L3.

[0109] In this embodiment, the filter and / or protective glass PB located between the tenth lens L10 and the imaging surface has an object-side surface S20 and an image-side surface S21. Light from the object can, for example, pass sequentially through each surface S1 to S21 and finally be imaged on the imaging surface S22, where an image sensor chip IMA may be disposed, for example.

[0110] Table 3 shows the radius of curvature R, thickness d / distance T, refractive index ND, and Abbe number Vd of each lens in the fixed-focus lens of Example 2.

[0111]

[0112]

[0113] Table 3

[0114] In this embodiment, the fixed-focus lens has an aperture number FNO = 1.12, a holographic height H = 13.19 mm, and an optical total length TTL = 29.50 mm.

[0115] In this embodiment, the object-side and image-side surfaces of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the ninth lens L9, and the tenth lens L10 are all aspherical surfaces, and the surface shape of each aspherical surface can be defined by formula (1) given in Embodiment 1 above. Table 4 gives the conic coefficient k and higher-order coefficients A4, A6, A8, and A19 that can be used for each aspherical mirror surface S1-S4, S6-S9, and S16-S19 in this embodiment. 10 A 12 and A14 .

[0116] Face No. k A4 A6 A8 A10 A12 A14 S1 -100.00 -8.23E-05 -5.19E-06 3.78E-07 -1.26E-08 2.24E-10 -1.73E-12 S2 0.05 -1.19E-04 -6.23E-06 -1.05E-06 8.14E-08 -3.17E-09 2.65E-11 S3 -3.27 -3.15E-04 -5.41E-05 4.31E-06 -1.57E-07 2.27E-09 -1.08E-11 S4 -5.95 -3.78E-04 1.93E-05 1.44E-07 6.76E-09 -4.89E-10 9.12E-12 S6 -14.51 -1.51E-04 1.66E-06 3.99E-08 9.33E-10 1.24E-11 -1.76E-13 S7 -21.10 -4.00E-04 9.63E-07 4.47E-08 2.99E-10 8.31E-11 -1.72E-12 S8 24.91 -1.81E-04 -2.74E-06 5.32E-08 3.00E-09 1.76E-11 -1.75E-12 S9 0.01 3.08E-05 -4.47E-08 -3.67E-09 3.16E-09 -4.86E-11 2.48E-13 S16 -8.33 7.49E-04 -5.65E-06 -2.83E-07 6.04E-09 -1.15E-10 3.37E-12 S17 -8.11 1.36E-03 -2.81E-05 4.19E-07 -3.78E-09 -2.88E-10 7.17E-12 S18 -7.83 -9.45E-04 -7.22E-05 2.68E-06 -7.90E-08 9.98E-10 -1.27E-12 S19 -6.18 -1.14E-03 -1.57E-05 3.33E-07 -2.68E-09 8.43E-11 -1.11E-12

[0117] Table 4

[0118] Example 3

[0119] Figure 3 A structure diagram of a fixed focus lens according to Embodiment 3 of the present application is shown, and the following refers to Figure 3 A fixed focus lens according to Embodiment 3 of the present application is described.

[0120] As shown in Figure 3 , the fixed focus lens comprises, in order from the object side to the image side along the optical axis, a first lens L1, a second lens L2, a stop STO, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9, a tenth lens L10, a filter and / or protective glass PB, and an imaging surface (IMA). Among them, the sixth lens L6, the seventh lens L7 and the eighth lens L8 are cemented to form a three-cemented lens group.

[0121] In this embodiment, the first lens L1 has a negative refractive power, the object side surface S1 is concave, and the image side surface S2 is concave. The second lens L2 has a negative refractive power, the object side surface S3 is concave, and the image side surface S4 is convex. The third lens L3 has a positive refractive power, the object side surface S6 is convex, and the image side surface S7 is concave. The fourth lens L4 has a positive refractive power, the object side surface S8 is convex, and the image side surface S9 is convex. The fifth lens L5 has a positive refractive power, the object side surface S10 is convex, and the image side surface S11 is convex. The sixth lens L6 has a positive refractive power, the object side surface S12 is convex, and the image side surface S13 is convex. The seventh lens L7 has a negative refractive power, the object side surface S13 is concave, and the image side surface S14 is concave. The eighth lens L8 has a positive refractive power, the object side surface S14 is convex, and the image side surface S15 is convex. The ninth lens L9 has a negative refractive power, the object side surface S16 is concave, and the image side surface S17 is convex. The tenth lens L10 has a positive refractive power, the object side surface S18 is convex, and the image side surface S19 is concave.

[0122] In this embodiment, the stop STO of the fixed focus lens is arranged between the second lens L2 and the third lens L3.

[0123] In this embodiment, the filter and / or protective glass PB between the tenth lens L10 and the imaging surface has an object side surface S20 and an image side surface S21. Light from the object can pass through each surface S1 to S21 in order and finally be imaged on the imaging surface S22, for example, wherein an image sensing chip IMA can be arranged at the imaging surface, for example.

[0124] Table 5 shows the radius of curvature R, thickness d / distance T, refractive index ND, and Abbe number Vd of each lens in the fixed-focus lens of Example 3.

[0125]

[0126] Table 5

[0127] In this embodiment, the fixed-focus lens has an aperture number FNO = 1.05, a holographic height H = 12.96 mm, and an optical total length TTL = 30.15 mm.

[0128] In this embodiment, the object-side and image-side surfaces of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the ninth lens L9, and the tenth lens L10 are all aspherical surfaces, and the surface shape of each aspherical surface can be defined by formula (1) given in Embodiment 1 above. Table 6 gives the conic coefficient k and higher-order coefficients A4, A6, A8, and A19 that can be used for each aspherical mirror surface S1-S4, S6-S9, and S16-S19 in this embodiment. 10 A 12 and A 14 .

[0129] Face No. k A4 A6 A8 A10 A12 A14 S1 -87.05 -5.60E-05 -6.86E-06 4.65E-07 -1.14E-08 1.51E-10 -6.53E-13 S2 0.14 8.59E-06 -5.84E-06 -6.88E-07 7.39E-08 -3.12E-09 4.72E-11 S3 -4.59 -3.70E-04 -5.70E-05 4.40E-06 -1.55E-07 2.24E-09 -1.19E-12 S4 -5.88 -4.44E-04 1.13E-05 -1.32E-08 9.51E-09 -1.98E-10 9.79E-13 S6 -15.48 -1.19E-04 2.01E-06 2.95E-08 9.97E-10 2.82E-11 -5.85E-13 S7 -21.29 -4.35E-04 6.96E-08 5.66E-08 9.65E-10 9.28E-11 -1.65E-12 S8 -23.66 -1.86E-04 -2.34E-06 4.98E-08 2.50E-09 1.18E-11 -1.28E-12 S9 -0.35 4.42E-05 1.26E-06 -2.25E-08 2.82E-09 -4.99E-11 5.78E-14 S16 -8.81 7.51E-04 -5.71E-06 -2.34E-07 7.01E-09 -1.47E-10 7.03E-13 S17 -4.90 1.26E-03 -2.84E-05 4.03E-07 -2.62E-09 -2.48E-10 3.68E-12 S18 -7.10 -7.33E-04 -6.83E-05 2.80E-06 -7.87E-08 9.46E-10 7.82E-13 S19 -4.66 -1.09E-03 -9.18E-06 3.79E-07 -4.50E-09 4.44E-11 2.53E-13

[0130] Table 6

[0131] Example 4

[0132] Figure 4 A schematic diagram of the fixed-focus lens according to Embodiment 4 of this application is shown below. Figure 4 Describes a fixed-focus lens according to Embodiment 4 of this application.

[0133] like Figure 4 As shown, the fixed-focus lens, along the optical axis from the object side to the image side, includes, in sequence: a first lens L1, a second lens L2, an aperture stop STO, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, an eighth lens L8, a ninth lens L9, a tenth lens L10, a filter and / or protective glass PB, and an imaging plane (IMA). The sixth lens L6, the seventh lens L7, and the eighth lens L8 are cemented together to form a cemented triplet lens group.

[0134] In this embodiment, the first lens L1 has a negative focal power, the object side S1 is convex, and the image side S2 is concave. The second lens L2 has a positive focal power, the object side S3 is concave, and the image side S4 is convex. The third lens L3 has a negative focal power, the object side S6 is concave, and the image side S7 is concave. The fourth lens L4 has a positive focal power, the object side S8 is convex, and the image side S9 is convex. The fifth lens L5 has a positive focal power, the object side S10 is convex, and the image side S11 is convex. The sixth lens L6 has a positive focal power, the object side S12 is convex, and the image side S13 is convex. The seventh lens L7 has a negative focal power, the object side S13 is concave, and the image side S14 is concave. The eighth lens L8 has a positive focal power, the object side S14 is convex, and the image side S15 is convex. The ninth lens L9 has a negative focal power, the object side S16 is concave, and the image side S17 is convex. The tenth lens L10 has a positive focal power, the object side S18 is convex, and the image side S19 is concave.

[0135] In this embodiment, the stop STO of the fixed focus lens is disposed between the second lens L2 and the third lens L3.

[0136] In this embodiment, the filter and / or protective glass PB between the tenth lens L10 and the imaging surface has an object side S20 and an image side S21. Light from the object can pass through the surfaces S1 to S21 in sequence, for example, and finally be imaged on the imaging surface S22, where an image sensor chip IMA can be disposed, for example.

[0137] Table 7 shows the radius of curvature R, the thickness d / distance T, the refractive index ND, and the Abbe number Vd of each lens of the fixed focus lens of embodiment 4.

[0138]

[0139]

[0140] Table 7

[0141] In this embodiment, the fixed focus lens has an aperture number FNO = 1.08, a total image height H = 12.96 mm, and an overall optical length TTL = 30.00 mm.

[0142] In this embodiment, the object side and the image side of the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the ninth lens L9, and the tenth lens L10 are aspherical surfaces, each of which can be defined by the formula (1) given in embodiment 1 above. Table 8 gives the conic constant k and the higher order constants A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28, A30, A32, A34, A36, A38, A40, A42, A44, A46, A48, A50, A52, A54, A56, A58, A60, A62, A64, A66, A68, A70, A72, A74, A76, A78, A80, A82, A84, A86, A88, A90, A92, A94, A96, A98, and A100 of the aspherical surfaces S1-S4, S6-S9, S16-S19 that can be used in this embodiment. 10 12 A​14 .

[0143]

[0144]

[0145] Table 8

[0146] In summary, Embodiments 1 to 4 respectively satisfy the relationships shown in Table 9 below.

[0147] Conditional Example Example 1 Example 2 Example 3 Example 4 F / TTL 0.245 0.241 0.263 0.248 TTL / BFL 6.134 6.187 6.030 6.019 F1 / F -1.993 -2.085 -1.672 -2.071 F2 / F -21.731 -31.981 -12.680 2.900 T12 / TTL 0.119 0.142 0.107 0.097 F3 / F 9.438 -33.682 17.897 -2.440 ND2 / ND3 1.000 1.000 1.012 1.012 F4 / F 2.858 3.194 2.329 2.374 F5 / F 6.406 2.921 4.539 3.450 DM5 / TTL 0.400 0.399 0.433 0.416 F6 / F 1.532 1.259 1.312 1.451 F7 / F -0.882 -0.717 -0.741 -0.813 F8 / F 1.191 1.098 1.070 1.454 Fa / F 1.843 2.325 2.218 4.352 da / TTL 0.313 0.305 0.303 0.268 F9 / F -4.043 -2.750 -4.250 -3.922 F10 / F 5.479 3.836 5.717 3.112 F9 / F10 -0.738 -0.717 -0.743 -1.260 (R101+R102) / (R101-R102) -28.252 -9.371 -25.047 -8.910 ENPD / F 0.909 0.893 0.952 0.926

[0148] Table 9

[0149] The present application also provides an electronic device, which can include the fixed-focus lens according to the above embodiments of the present application and an imaging element for converting an optical image formed by the fixed-focus lens into an electrical signal.

[0150] The above description is merely exemplary of the application and the application principles 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 above technical features, and should also cover other technical solutions formed by any combinations of the above technical features or equivalent features without departing from the inventive concept. For example, the above features can be replaced with the technical features disclosed in the present application (but not limited to) having similar functions to form technical solutions.

Claims

1. A fixed-focus lens, characterized in that, Along the optical axis from the object side to the image side, the following are included in sequence: The first lens with negative optical power A second lens with optical power, A third lens with optical power. A fourth lens with positive optical power. A fifth lens with positive optical power. A sixth lens with positive optical power. The seventh lens with negative optical power. The eighth lens with positive optical power. A ninth lens with negative optical power, and A tenth lens with positive optical power; At least one of the second lens and the third lens has negative optical power; The fixed-focus lens has ten lenses with optical power. Wherein, the combined focal length Fa of the sixth lens, the seventh lens and the eighth lens and the total effective focal length F of the fixed-focus lens satisfy: 1.8≤Fa / F≤4.5; The effective focal length F1 of the first lens and the total effective focal length F of the fixed-focus lens satisfy the following condition: -2.2≤F1 / F≤-1.

5.

2. The fixed-focus lens according to claim 1, characterized in that, The image-side surface of the first lens is concave; The object-side surface of the second lens is concave, and the image-side surface is convex. The image-side surface of the third lens is concave; The object-side surface of the fourth lens is convex, and the image-side surface is also convex. The image-side surface of the fifth lens is convex. The object-side surface of the sixth lens is convex, and the image-side surface is also convex. The object-side surface of the seventh lens is concave, and the image-side surface is also concave. The object-side surface of the eighth lens is convex, and the image-side surface is also convex. The object-side surface of the ninth lens is concave, and the image-side surface is convex; and The object-side surface of the tenth lens is convex, and the image-side surface is concave.

3. The fixed-focus lens according to claim 1, characterized in that, The sixth lens, the seventh lens, and the eighth lens are a cemented triplet lens group.

4. The fixed-focus lens according to any one of claims 1 to 3, characterized in that, The total effective focal length F of the fixed-focus lens and the distance TTL from the center of the object side of the first lens to the imaging surface of the fixed-focus lens on the optical axis satisfy the following condition: 0.23≤F / TTL≤0.

27.

5. The fixed-focus lens according to any one of claims 1 to 3, characterized in that, The distance TTL from the center of the object side of the first lens to the imaging surface of the fixed-focus lens on the optical axis and the distance BFL from the center of the image side of the tenth lens to the imaging surface on the optical axis satisfy: 5.9≤TTL / BFL≤6.

3.

6. The fixed-focus lens according to any one of claims 1 to 3, characterized in that, The effective focal length F2 of the second lens and the total effective focal length F of the fixed-focus lens satisfy: -32.5≤F2 / F≤5.

5.

7. The fixed-focus lens according to any one of claims 1 to 3, characterized in that, The air gap T12 between the first lens and the second lens on the optical axis and the distance TTL from the center of the object side of the first lens to the imaging surface of the fixed-focus lens on the optical axis satisfy the following: 0.08≤T12 / TTL≤0.

15.

8. The fixed-focus lens according to any one of claims 1 to 3, characterized in that, The effective focal length F3 of the third lens and the total effective focal length F of the fixed-focus lens satisfy the following condition: -34.5≤F3 / F≤18.

5.

9. The fixed-focus lens according to any one of claims 1 to 3, characterized in that, The refractive index ND2 of the second lens and the refractive index ND3 of the third lens satisfy the condition: 0.95≤ND2 / ND3≤1.

05.

10. The fixed-focus lens according to any one of claims 1 to 3, characterized in that, The effective focal length F4 of the fourth lens and the total effective focal length F of the fixed-focus lens satisfy the following condition: 2.0≤F4 / F≤3.

4.

11. The fixed-focus lens according to any one of claims 1 to 3, characterized in that, The effective focal length F5 of the fifth lens and the total effective focal length F of the fixed-focus lens satisfy the following condition: 2.3≤F5 / F≤6.

5.

12. The fixed-focus lens according to any one of claims 1 to 3, characterized in that, The maximum optical aperture value DM5 of the object side and image side of the fifth lens and the distance TTL from the center of the object side of the first lens to the imaging surface of the fixed-focus lens on the optical axis satisfy the following condition: 0.38≤DM5 / TTL≤0.

44.

13. The fixed-focus lens according to any one of claims 1 to 3, characterized in that, The effective focal length F6 of the sixth lens and the total effective focal length F of the fixed-focus lens satisfy the following condition: 1.15≤F6 / F≤1.

75.

14. The fixed-focus lens according to any one of claims 1 to 3, characterized in that, The effective focal length F7 of the seventh lens and the total effective focal length F of the fixed-focus lens satisfy the following condition: -1.1≤F7 / F≤-0.

6.

15. The fixed-focus lens according to any one of claims 1 to 3, characterized in that, The effective focal length F8 of the eighth lens and the total effective focal length F of the fixed-focus lens satisfy the following condition: 0.9≤F8 / F≤1.

5.

16. The fixed-focus lens according to any one of claims 1 to 3, characterized in that, The sum of the center thicknesses da of the sixth lens, the seventh lens, and the eighth lens on the optical axis and the distance TTL from the center of the object side surface of the first lens to the imaging surface of the fixed-focus lens on the optical axis satisfy the following condition: 0.25≤da / TTL≤0.

33.

17. The fixed-focus lens according to any one of claims 1 to 3, characterized in that, The effective focal length F9 of the ninth lens and the total effective focal length F of the fixed-focus lens satisfy the following condition: -4.5≤F9 / F≤-1.

5.

18. The fixed-focus lens according to any one of claims 1 to 3, characterized in that, The effective focal length F10 of the tenth lens and the total effective focal length F of the fixed-focus lens satisfy the following condition: 1.9≤F10 / F≤5.

8.

19. The fixed-focus lens according to any one of claims 1 to 3, characterized in that, The effective focal length F9 of the ninth lens and the effective focal length F10 of the tenth lens satisfy the condition: -1.35≤F9 / F10≤-0.

6.

20. The fixed-focus lens according to any one of claims 1 to 3, characterized in that, The radius of curvature R101 of the object side of the tenth lens and the radius of curvature R102 of the image side of the tenth lens satisfy: -29≤(R101+R102) / (R101-R102)≤-3.

21. The fixed-focus lens according to any one of claims 1 to 3, characterized in that, The entrance pupil diameter ENPD of the fixed-focus lens and the total effective focal length F of the fixed-focus lens satisfy the following condition: 0.85≤ENPD / F≤0.

98.

22. The fixed-focus lens according to any one of claims 1 to 3, characterized in that, The fixed-focus lens satisfies at least one of the following conditions: 1.843≤Fa / F≤4.352; 0.241≤F / TTL≤0.263; 6.019≤TTL / BFL≤6.187; -2.085≤F1 / F≤-1.672; -31.981≤F2 / F≤2.900; 0.097≤T12 / TTL≤0.142; -33.682≤F3 / F≤17.897; 1.000≤ND2 / ND3≤1.012; 2.329≤F4 / F≤3.194; 2.921≤F5 / F≤6.406; 0.399≤DM5 / TTL≤0.433; 1.259≤F6 / F≤1.532; -0.882≤F7 / F≤-0.717; 1.070≤F8 / F≤1.454; 0.268≤da / TTL≤0.313; -4.250≤F9 / F≤-2.750; 3.1 12≤F10 / F≤5.717; -1.260≤F9 / F10≤-0.717; -28.252≤(R101+R102) / (R101-R102)≤-8.910; 0.893≤ENPD / F≤0.952; Where Fa is the combined focal length of the sixth, seventh, and eighth lenses; F is the total effective focal length of the fixed-focus lens; TTL is the distance from the center of the object-side surface of the first lens to the imaging plane of the fixed-focus lens on the optical axis; BFL is the distance from the center of the image-side surface of the tenth lens to the imaging plane on the optical axis; F1 is the effective focal length of the first lens; F2 is the effective focal length of the second lens; T12 is the air gap between the first and second lenses on the optical axis; F3 is the effective focal length of the third lens; ND2 is the refractive index of the second lens; ND3 is the refractive index of the third lens; and F4 is the total effective focal length of the fixed-focus lens. The effective focal length of the fourth lens is defined as follows: F5 is the effective focal length of the fifth lens; DM5 is the maximum optical aperture value of the object-side and image-side surfaces of the fifth lens; F6 is the effective focal length of the sixth lens; F7 is the effective focal length of the seventh lens; F8 is the effective focal length of the eighth lens; da is the sum of the center thicknesses of the sixth, seventh, and eighth lenses along the optical axis; F9 is the effective focal length of the ninth lens; F10 is the effective focal length of the tenth lens; R101 is the radius of curvature of the object-side surface of the tenth lens; R102 is the radius of curvature of the image-side surface of the tenth lens; and ENPD is the entrance pupil diameter of the fixed-focus lens.

Images