Prime lens

Abstract

The utility model discloses a prime lens. The prime lens sequentially comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens from an object side to an image side along an optical axis, the object side surface of the second lens is a concave surface, and the image side surface of the second lens is a convex surface; the third lens has focal power; the fourth lens has positive focal power; the fifth lens has positive focal power, and the image side surface of the fifth lens is a convex surface; the object side surface of the sixth lens is a convex surface, and the image side surface of the sixth lens is a convex surface; the object side surface of the seventh lens is a concave surface, and the image side surface of the seventh lens is a concave surface; the eighth lens has positive focal power; the ninth lens has negative focal power; the object side surface of the tenth lens is a convex surface, and the image side surface of the tenth lens is a concave surface; wherein the sixth lens, the seventh lens and the eighth lens form a three-bonding lens group which is bonded with each other.

Description

Technical Field

[0001] The present application relates to the field of optical elements, and more specifically, to a fixed-focus lens. Background Art

[0002] As society pays more and more attention to work in the field of public security, the market demand and requirements for fixed-focus lenses for security such as monitoring facilities are also increasing.

[0003] Fixed-focus lenses are widely used in various fields because of their advantages such as high-definition imaging and clear imaging under low-light conditions. In order to meet higher image quality requirements, large-size photosensitive chips are needed. Large-size chips have larger 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 at the same time, larger and longer optical system sizes are often required. For example, the fixed-focus lenses currently on the market that meet the requirements of 1.0F aperture and 1 / 1.2" chip size usually have a total optical length of about 50mm and are relatively large in size.

[0004] Therefore, the current market demand is to make such lenses smaller in size. At the same time, the performance of the lenses needs to be further improved in one or more aspects such as high resolution, large aperture, large target area, low cost and good thermal stability. Utility Model Content

[0005] The present application provides a fixed-focus lens, which may include, in order from the object side to the image side along the optical axis: a first lens with negative optical power; a second lens with optical power, whose object-side surface is concave and whose image-side surface is convex; a third lens with optical power; a fourth lens with positive optical power; a fifth lens with positive optical power, whose image-side surface is convex; a sixth lens with positive optical power, whose object-side surface is convex and whose image-side surface is convex; a seventh lens with negative optical power, whose object-side surface is concave and whose image-side surface is concave; an eighth lens with positive optical power; a ninth lens with negative optical power; and a tenth lens with positive optical power, whose object-side surface is convex and whose image-side surface is concave; wherein the sixth lens, the seventh lens and the eighth lens may be a cemented triplet lens group.

[0006] In one embodiment, the image side surface of the first lens may be concave; the object side surface of the fourth lens may be convex, and the image side surface may be convex; the object side surface of the eighth lens may be convex, and the image side surface may be convex; the object side surface of the ninth lens may be concave, and the image side surface may be convex.

[0007] In one embodiment, the total effective focal length F of the fixed-focus lens 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 may satisfy: 0.23≤F / TTL≤0.27.

[0008] In one embodiment, a 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 and a distance BFL from the center of the image-side surface of the tenth lens to the imaging surface on the optical axis may satisfy: 5.9≤TTL / BFL≤6.3.

[0009] In one embodiment, the effective focal length F1 of the first lens and the total effective focal length F of the fixed-focus lens may satisfy: -2.2≤F1 / F≤-1.5.

[0010] In one embodiment, the effective focal length F2 of the second lens and the total effective focal length F of the fixed-focus lens may satisfy: -32.5≤F2 / F≤5.5.

[0011] In one embodiment, the air interval T12 between the first lens and the second 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 may satisfy: 0.08≤T12 / TTL≤0.15.

[0012] In one embodiment, the effective focal length F3 of the third lens and the total effective focal length F of the fixed-focus lens may satisfy: -34.5≤F3 / F≤18.5.

[0013] In one embodiment, the refractive index ND2 of the second lens and the refractive index ND3 of the third lens may satisfy: 0.95≤ND2 / ND3≤1.05.

[0014] In one embodiment, the effective focal length F4 of the fourth lens and the total effective focal length F of the fixed-focus lens may satisfy: 2.0≤F4 / F≤3.4.

[0015] In one embodiment, the effective focal length F5 of the fifth lens and the total effective focal length F of the fixed-focus lens may satisfy: 2.3≤F5 / F≤6.5.

[0016] In one embodiment, the maximum optical full aperture value DM5 of the object side surface and the image side surface of the fifth lens and the distance TTL on the optical axis from the center of the object side surface of the first lens to the imaging surface of the fixed focus lens may satisfy: 0.38≤DM5 / TTL≤0.44.

[0017] In one embodiment, the effective focal length F6 of the sixth lens and the total effective focal length F of the fixed-focus lens may satisfy: 1.15≤F6 / F≤1.75.

[0018] In one embodiment, the effective focal length F7 of the seventh lens and the total effective focal length F of the fixed-focus lens may satisfy: -1.1≤F7 / F≤-0.6.

[0019] In one embodiment, the effective focal length F8 of the eighth lens and the total effective focal length F of the fixed-focus lens may satisfy: 0.9≤F8 / F≤1.5.

[0020] In one embodiment, 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 may satisfy: 1.8≤Fa / F≤4.5.

[0021] In one embodiment, the sum da of the center 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 surface of the first lens to the imaging surface of the fixed-focus lens on the optical axis may 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-focus lens may 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-focus lens may 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 may satisfy: -1.35≤F9 / F10≤-0.6.

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

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

[0027] The fixed-focus lens of the present application includes the first to tenth lenses arranged in sequence from the object side to the image side along the optical axis, wherein the first lens has negative optical power, the second lens is a concave-convex surface type, the fourth lens has positive optical power, the fifth lens has positive optical power and the image side is convex, the sixth lens has positive optical power and a convex-convex surface type, the seventh lens has negative optical power and a concave-concave surface type, the eighth lens has positive optical power, the ninth lens has negative optical power, and the tenth lens has positive optical power and a convex-concave surface type; and the sixth lens, the seventh lens and the eighth lens are a three-cemented lens group that are glued to each other. Through this setting of the lens, various aberrations can be balanced, the resolution can be improved, and 4K high resolution can be achieved; at the same time, the tolerance sensitivity between lenses can be reduced, which is conducive to ensuring production yield.

[0028] The fixed-focus lens of the present application uses ten lenses. By reasonably setting some parameters of the lens' optical power, surface shape, curvature radius, and refractive index, the lens can have at least one of the following beneficial effects: 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 -40℃ to +80℃. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

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

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

[0034] In order to facilitate the understanding of the present application, the present application will be described more comprehensively below with reference to the relevant drawings. It should be understood that these detailed descriptions are only descriptions of exemplary embodiments of the present application, and do not limit the scope of the present application in any way. Throughout the specification, the same figure numbers refer to the same 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 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 application, the first lens discussed below may also be referred to as the second lens or the third lens.

[0036] 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.

[0037] In this article, 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 subject is called the object side of the lens, and the surface of each lens closest to the imaging side is called the image side of the lens.

[0038] 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.

[0039] 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 sense unless explicitly defined in this article.

[0040] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

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

[0042] In an exemplary embodiment, the fixed focus lens according to the present application may include, for example, ten lenses having optical power, namely, 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 may be arranged in sequence from the object side to the image side along the optical axis.

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

[0044] In exemplary embodiments, the sixth lens, the seventh lens, and the eighth lens may be a triplet lens group cemented to each other.

[0045] In an exemplary embodiment, the first lens may have a negative optical power. The image side surface of the first lens may be a concave surface. Through this arrangement, the first lens may diverge a large field of view light entering the optical system to the rear optical system, which may effectively increase the amount of light passing through and improve the resolution.

[0046] In an exemplary embodiment, the second lens may have a concave-convex surface, which can smooth the angle of light passing through the second lens, correct aberrations, and improve lens resolution.

[0047] In an exemplary embodiment, the third lens may be located next to the aperture, and may balance the aberration caused by light passing through the aperture to ensure image quality. Exemplarily, the aperture may be located between the second lens and the third lens, for example.

[0048] In an exemplary embodiment, the fourth lens may have positive power. The fourth lens may have a convex-convex surface. By setting the fourth lens to have positive power and a convex image side surface, the light trend can be smoothed and the light direction can be effectively controlled, which is conducive to achieving a small size of the lens.

[0049] In an exemplary embodiment, the fifth lens may have positive power. The image side surface of the fifth lens may be a convex surface. By setting the fifth lens in this way, the light trend can be further controlled, which is conducive to achieving high image quality under a large target surface; at the same time, the material of the fifth lens may be, for example, glass, which is conducive to balancing high and low temperature performance.

[0050] In an exemplary embodiment, the sixth lens may have positive power. The sixth lens may have a convex-convex surface. By setting the sixth lens in this way, the field curvature of the system can be balanced, which is conducive to achieving high image quality. Exemplarily, the sixth lens, the seventh lens having negative power and a concave-concave lens shape, and the eighth lens having positive power and a convex-convex lens shape can be glued to form a triplet lens group, which can effectively balance various aberrations, improve resolution, and achieve 4K high resolution; at the same time, it can reduce the tolerance sensitivity between lenses, which is conducive to improving production yield.

[0051] In an exemplary embodiment, the seventh lens may have negative power. The seventh lens may have a concave-concave surface. The seventh lens having negative power and a concave-concave shape may be used in combination with the sixth lens having positive power and a convex-convex lens shape to balance the system spherical aberration, improve the resolution, and achieve high resolution.

[0052] In an exemplary embodiment, the eighth lens may have positive power. The eighth lens may have a convex-convex surface type. The eighth lens having positive power and a convex-convex shape may be used in combination with the seventh lens having negative power and a concave-concave lens shape, which may balance the astigmatism generated by light passing through the system, and is conducive to ensuring image quality under a large target surface.

[0053] In an exemplary embodiment, the ninth lens may have a negative optical power. The ninth lens may have a concave-convex surface. The ninth lens has a negative optical power and a concave-convex shape, which can be matched with a positive lens at the rear end (for example, a tenth lens with positive optical power) to balance the aberration of the entire system and improve the resolution.

[0054] In an exemplary embodiment, the tenth lens may have positive power. The tenth lens may have a convex-concave surface. The tenth lens has positive power, which can ensure the height of the light at the rear end, which is conducive to achieving a large target surface.

[0055] In an exemplary embodiment, the fixed focus lens according to the present application may include an aperture. The aperture may be located, for example, between the second lens and the third lens, which can effectively converge the light entering the optical system, shorten the total length of the optical system, and reduce the maximum aperture of the optical system, which is conducive to achieving a miniaturized design. It should be noted that the position of the aperture disclosed herein is only an example and not a limitation; in alternative embodiments, the aperture may also be set at other positions according to actual needs.

[0056] In an exemplary embodiment, the fixed-focus lens may further include a photosensitive element disposed on the imaging surface. Optionally, the photosensitive element disposed on the imaging surface may be, for example, a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS).

[0057] In an exemplary embodiment, the object side and image side of each lens of the first lens to the tenth lens included in the fixed focus lens may have an aspherical mirror surface. For example, in one embodiment, the object side and image side of the first lens, the object side and image side of the second lens, the object side and image side of the third lens, the object side and image side of the fourth lens, the object side and image side of the ninth lens, and the object side and image side of the tenth lens may be aspherical mirror surfaces.

[0058] In an exemplary embodiment, the object-side surface and the image-side surface of the ninth lens and the object-side surface and the image-side surface of the tenth lens may each have at least one inflection point.

[0059] In an exemplary embodiment, the fixed focus lens can be made of a glass-plastic hybrid material. The use of glass-plastic hybrid materials for each lens in the lens can help reduce the cost of the optical system and balance the high and low temperature performance of the optical lens, so that the lens can achieve high imaging quality in the range of -40°C to +80°C, for example.

[0060] In an exemplary embodiment, the sixth lens, the seventh lens and the eighth lens can be combined into a triplet lens group, which can balance various aberrations, improve resolution, and achieve 4K high resolution; at the same time, it can reduce the tolerance sensitivity between lenses, which is beneficial to ensure production yield.

[0061] In an exemplary embodiment, the aperture number FNO of the fixed-focus lens according to the present application may satisfy FNO≤1.12, for example, so as to ensure that the optical lens has a large aperture characteristic.

[0062] In an exemplary embodiment, the full image height H of the fixed-focus lens according to the present application can satisfy H≥12.9 mm, for example. The lens has a large target surface, which is conducive to having higher optical performance and facilitating the matching of the optical lens with sensors of different specifications.

[0063] In an exemplary embodiment, the total optical length of the fixed-focus lens according to the present application, that is, 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, can satisfy TTL≤30.2 mm, so that the total length of the lens is short and the structure is compact, which is conducive to miniaturization.

[0064] The fixed-focus lens according to the exemplary embodiment of the present application includes the first to tenth lenses arranged in sequence from the object side to the image side along the optical axis, wherein the first lens has negative optical power, the second lens is a concave-convex surface type, the fourth lens has positive optical power, the fifth lens has positive optical power and the image side is convex, the sixth lens has positive optical power and a convex-convex surface type, the seventh lens has negative optical power and a concave-concave surface type, the eighth lens has positive optical power, the ninth lens has negative optical power, and the tenth lens has positive optical power and a convex-concave surface type; and the sixth lens, the seventh lens and the eighth lens are a three-cemented lens group that are glued to each other. Through this setting of the lens, various aberrations can be balanced, the resolution can be improved, and 4K high resolution can be achieved; at the same time, the tolerance sensitivity between lenses can be reduced, which is conducive to ensuring the production yield.

[0065] The fixed-focus lens according to the exemplary embodiment of the present application uses ten lenses. By reasonably setting some parameters of the lens' optical power, surface shape, radius of curvature, and refractive index, the lens can have at least one of the following beneficial effects: 4K high resolution, large aperture (e.g., FNO≤1.12), large target surface (e.g., full image height H≥12.9mm), low cost, small size (e.g., TTL≤30.2mm), and clear imaging in an environment of, for example, -40°C to +80°C.

[0066] In an exemplary embodiment, the fixed-focus lens according to the present application may 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. By controlling the ratio of the two within this range, under a certain system focal length value, the total optical length of the system is reasonably controlled, so that the total optical length of the system is small, which is conducive to realizing a small volume of the system.

[0067] In an exemplary embodiment, the fixed-focus lens according to the present application may satisfy: 5.9≤TTL / BFL≤6.3, wherein 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. By controlling the ratio of the two within this range, on the basis of achieving miniaturization, by controlling the length of the system optical back focus BFL, the back focus of the lens is made longer, which helps to reserve space for the installation of optical elements, facilitates the assembly of the optical lens, avoids interference, and helps to improve the assembly yield of the optical lens.

[0068] In an exemplary embodiment, the fixed-focus lens according to the present application may 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 this range, the incident light can be effectively converged, and the large field of view light entering the optical system can be diverged to the rear of the optical system, which can effectively increase the amount of light passing through, improve the illumination, and effectively expand the field of view angle.

[0069] In an exemplary embodiment, the fixed-focus lens according to the present application may 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 this range, it is helpful to smoothly transition the light, reduce the sensitivity of the first lens, correct aberrations, and improve the resolution of the lens; at the same time, it can help to increase the aperture, so that the aperture satisfies, for example, FNO≤1.12.

[0070] In an exemplary embodiment, the fixed-focus lens according to the present application may satisfy: 0.08≤T12 / TTL≤0.15, wherein T12 is the air gap between 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 this range, it is beneficial to maintain a suitable air gap between the first lens and the second lens, to reduce the aberration generated at the front end of the lens, and to achieve high image quality of the lens.

[0071] In an exemplary embodiment, 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 this range, the aberration generated when the light passes through the aperture can be balanced to ensure image quality; at the same time, it can help to increase the aperture so that the aperture satisfies, for example, FNO≤1.12.

[0072] In an exemplary embodiment, the fixed focus lens according to the present application may 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 this range, the aberration generated when the light passes through the aperture can be reduced, which is conducive to clear imaging of the lens.

[0073] In an exemplary embodiment, the fixed-focus lens according to the present application may 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 this range, astigmatism can be corrected while effectively converging light, which is beneficial for the lens to achieve a small size and high image quality.

[0074] In an exemplary embodiment, the fixed-focus lens according to the present application may 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 this range, the light trend can be further controlled, which is conducive to achieving high image quality under a large target surface, and at the same time, the effective focal length of the fifth lens can be kept stable within a large temperature range, which is conducive to balancing high and low temperature performance.

[0075] In an exemplary embodiment, the fixed-focus lens according to the present application may satisfy: 0.38≤DM5 / TTL≤0.44, where DM5 is the largest optical full aperture value between the object side and the image side of the fifth lens, 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 this range, the volume of the system can be reduced, which is conducive to the miniaturization of the lens.

[0076] In an exemplary embodiment, the fixed-focus lens according to the present application may 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 this range, the focal length value of the sixth lens is reasonably set to match the focal length value of the seventh lens, effectively balancing the field curvature of the system, improving the resolution, and achieving high resolution.

[0077] In an exemplary 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 this range, the focal length value of the seventh lens is reasonably set to match the focal length values ​​of the sixth lens and the eighth lens, effectively balancing the system spherical aberration, improving the resolution, and achieving high resolution.

[0078] In an exemplary 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 this range and reasonably setting the focal length value of the eighth lens to match the focal length value of the seventh lens, the astigmatism generated by the light passing through the system can be balanced, which is beneficial to ensuring the image quality under a large target surface.

[0079] In an exemplary embodiment, the fixed-focus lens according to the present application may satisfy: 1.8≤Fa / F≤4.5, wherein 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. Exemplarily, the sixth lens, the seventh lens, and the eighth lens may be glued together to form a triplet lens group, and Fa may be the effective focal length of the triplet 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 may be effectively reduced, the resolution may be improved, and 4K high resolution may be achieved; at the same time, the tolerance sensitivity between the lenses may be reduced, which is beneficial to improving the production yield. More specifically, Fa and F may further satisfy: 1.8≤Fa / F≤2.5.

[0080] In an exemplary embodiment, the fixed-focus lens according to the present application may satisfy: 0.25≤da / TTL≤0.33, where da is the sum of the center 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 this range and reasonably allocating the thickness value of the cemented lens, the material cost caused by the thickness can be reduced while balancing the system aberration, which is conducive to achieving low cost.

[0081] In an exemplary embodiment, 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 trend of light can be effectively controlled, the light can be smoothly transitioned, and the off-axis aberration can be effectively balanced, which is conducive to ensuring the image quality under a large target surface.

[0082] In an exemplary embodiment, 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 direction of the light can be effectively controlled, the height of the light can be ensured, and the light can be quickly focused on the imaging surface, which is conducive to achieving a large target surface and making the full image height H satisfy H≥12.9mm, for example.

[0083] In an exemplary embodiment, the fixed focus lens according to the present application may satisfy: -1.35≤F9 / F10≤-0.6, wherein 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 are reasonably allocated, and the positive and negative lenses are used in combination, the optical aberrations converging on the receiving chip are reduced, and high resolution is achieved. More specifically, F9 and F10 may further satisfy: -0.9≤F9 / F10≤-0.6.

[0084] In an exemplary embodiment, the fixed focus lens according to the present application may satisfy: -29≤(R101+R102) / (R101-R102)≤-3, wherein R101 is the radius of curvature of the object side surface of the tenth lens, and R102 is the radius of curvature of the image side surface of the tenth lens. By controlling the radius of curvature of the object side surface and the image side surface of the tenth lens to satisfy this conditional expression, it is beneficial to balance the system coma, to ensure the edge field image quality of the large target surface, and to improve the lens quality.

[0085] In an exemplary embodiment, the fixed-focus lens according to the present application may 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, which is conducive to achieving a large aperture, for example, satisfying FNO≤1.12.

[0086] In an exemplary embodiment, the fixed-focus lens of the present application may further include a filter and / or a protective glass disposed between the tenth lens and the imaging surface as required. The filter may filter light having a specific wavelength, and the protective glass may prevent the image side element (e.g., chip) of the fixed-focus lens from being damaged.

[0087] The fixed-focus lens according to the embodiment of the present application may use multiple lenses, such as the ten lenses described above. By reasonably setting the focal length, surface shape, radius of curvature, and refractive index of each lens, for example, some parameters, the lens can have at least one of the following beneficial effects: 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 -40℃ to +80℃.

[0088] However, it should be understood by those skilled in the art that, without departing from the technical solution claimed in the present application, the number of lenses constituting the lens can be changed to obtain the various results and advantages described in this specification. For example, although ten lenses are described as an example in the embodiments, the fixed-focus lens is not limited to including ten lenses. If necessary, the fixed-focus lens may also include other numbers of lenses. The following further describes a specific embodiment of the fixed-focus lens applicable to the above-mentioned embodiments with reference to the accompanying drawings.

[0089] Example 1

[0090] Figure 1 is a schematic diagram of the structure of a fixed-focus lens according to Example 1 of the present application, and the following reference Figure 1 A fixed-focus lens according to Embodiment 1 of the present application is described.

[0091] like Figure 1 As shown, the fixed focus lens includes, from the object side to the image side along the optical axis, a first lens L1, a second lens L2, an aperture 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 imaging surface (IMA). The sixth lens L6, the seventh lens L7, and the eighth lens L8 are cemented together to form a triplet lens group.

[0092] In this embodiment, the first lens L1 has negative power, and its object side surface S1 is convex, and its image side surface S2 is concave. The second lens L2 has negative power, and its object side surface S3 is concave, and its image side surface S4 is convex. The third lens L3 has positive power, and its object side surface S6 is convex, and its image side surface S7 is concave. The fourth lens L4 has positive power, and its object side surface S8 is convex, and its image side surface S9 is convex. The fifth lens L5 has positive power, and its object side surface S10 is concave, and its image side surface S11 is convex. The sixth lens L6 has positive power, and its object side surface S12 is convex, and its image side surface S13 is convex. The seventh lens L7 has negative power, and its object side surface S13 is concave, and its image side surface S14 is concave. The eighth lens L8 has positive power, and its object side surface S14 is convex, and its image side surface S15 is convex. The ninth lens L9 has negative refractive power, its object-side surface S16 is concave, and its image-side surface S17 is convex. The tenth lens L10 has positive refractive power, its object-side surface S18 is convex, and its image-side surface S19 is concave.

[0093] In this embodiment, the stop STO of the fixed focus lens is disposed between the second lens L2 and the third lens L3.

[0094] 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 may, for example, sequentially pass through the surfaces S1 to S21 and finally be imaged on the imaging surface S22, where an image sensor chip IMA may be disposed at the imaging surface.

[0095] Table 1 shows the curvature radius R, thickness d / distance T, refractive index ND and Abbe number Vd of each lens of the fixed focus lens of Example 1. It should be understood that the thickness d / distance T of the row where S1 is located is the center thickness of the first lens L1, the thickness d / distance T of the row where 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 where S3 is located is the center thickness of the second lens L2, and so on.

[0096]

[0097]

[0098] Table 1

[0099] In this embodiment, the aperture number FNO of the fixed-focus lens is 1.10, the full image height H is 13.54 mm, and the total optical length TTL is 30.15 mm.

[0100] In this embodiment, the object-side surface and the image-side surface 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 x of each aspherical lens can be defined by but not limited to the following aspherical surface formula:

[0101]

[0102] 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 above); k is the cone coefficient; Ai is the correction coefficient of the i-th order of the aspheric surface. Table 2 below gives the cone coefficient k and the high-order coefficients A4, A6, A8, A9 that can be used for each aspheric mirror surface S1-S4, S6-S9, S16-S19 in Example 1. 10 , A 12 and A 14 .

[0103] Face number 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

[0104] Table 2

[0105] Example 2

[0106] Figure 2 The structure diagram of the fixed focus lens according to Embodiment 2 of the present application is shown below. Figure 2 A fixed-focus lens according to Embodiment 2 of the present application is described. In this embodiment and the following embodiments, for the sake of brevity, some descriptions similar to Embodiment 1 will be omitted.

[0107] like Figure 2 As shown, the fixed focus lens includes, from the object side to the image side along the optical axis, a first lens L1, a second lens L2, an aperture 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 imaging surface (IMA). The sixth lens L6, the seventh lens L7, and the eighth lens L8 are cemented together to form a triplet lens group.

[0108] In this embodiment, the first lens L1 has negative power, and its object side surface S1 is convex, and its image side surface S2 is concave. The second lens L2 has negative power, and its object side surface S3 is concave, and its image side surface S4 is convex. The third lens L3 has negative power, and its object side surface S6 is convex, and its image side surface S7 is concave. The fourth lens L4 has positive power, and its object side surface S8 is convex, and its image side surface S9 is convex. The fifth lens L5 has positive power, and its object side surface S10 is flat, and its image side surface S11 is convex. The sixth lens L6 has positive power, and its object side surface S12 is convex, and its image side surface S13 is convex. The seventh lens L7 has negative power, and its object side surface S13 is concave, and its image side surface S14 is concave. The eighth lens L8 has positive power, and its object side surface S14 is convex, and its image side surface S15 is convex. The ninth lens L9 has negative refractive power, its object-side surface S16 is concave, and its image-side surface S17 is convex. The tenth lens L10 has positive refractive power, its object-side surface S18 is convex, and its image-side surface S19 is concave.

[0109] In this embodiment, the stop STO of the fixed focus lens is disposed between the second lens L2 and the third lens L3.

[0110] 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 may, for example, sequentially pass through the surfaces S1 to S21 and finally be imaged on the imaging surface S22, where an image sensor chip IMA may be disposed at the imaging surface.

[0111] Table 3 shows the curvature radius R, thickness d / distance T, refractive index ND, and Abbe number Vd of each lens of the fixed-focus lens of Example 2.

[0112]

[0113]

[0114] Table 3

[0115] In this embodiment, the aperture number FNO of the fixed-focus lens is 1.12, the total image height H is 13.19 mm, and the total optical length TTL is 29.50 mm.

[0116] In this embodiment, the object side surface and the image side surface 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 the formula (1) given in the above embodiment 1. Table 4 shows the cone coefficient k and the high-order coefficients A4, A6, A8, A9 that can be used for each aspherical mirror surface S1-S4, S6-S9, S16-S19 in this embodiment. 10 , A 12 and A14 .

[0117] Face number 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

[0118] Table 4

[0119] Example 3

[0120] Figure 3 The structure diagram of the fixed focus lens according to Embodiment 3 of the present application is shown below. Figure 3 A fixed-focus lens according to Embodiment 3 of the present application is described.

[0121] like Figure 3 As shown, the fixed focus lens includes, from the object side to the image side along the optical axis, a first lens L1, a second lens L2, an aperture 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 imaging surface (IMA). The sixth lens L6, the seventh lens L7, and the eighth lens L8 are cemented together to form a triplet lens group.

[0122] In this embodiment, the first lens L1 has negative power, and its object side surface S1 is concave, and its image side surface S2 is concave. The second lens L2 has negative power, and its object side surface S3 is concave, and its image side surface S4 is convex. The third lens L3 has positive power, and its object side surface S6 is convex, and its image side surface S7 is concave. The fourth lens L4 has positive power, and its object side surface S8 is convex, and its image side surface S9 is convex. The fifth lens L5 has positive power, and its object side surface S10 is convex, and its image side surface S11 is convex. The sixth lens L6 has positive power, and its object side surface S12 is convex, and its image side surface S13 is convex. The seventh lens L7 has negative power, and its object side surface S13 is concave, and its image side surface S14 is concave. The eighth lens L8 has positive power, and its object side surface S14 is convex, and its image side surface S15 is convex. The ninth lens L9 has negative refractive power, its object-side surface S16 is concave, and its image-side surface S17 is convex. The tenth lens L10 has positive refractive power, its object-side surface S18 is convex, and its image-side surface S19 is concave.

[0123] In this embodiment, the stop STO of the fixed focus lens is disposed between the second lens L2 and the third lens L3.

[0124] 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 may, for example, sequentially pass through the surfaces S1 to S21 and finally be imaged on the imaging surface S22, where an image sensor chip IMA may be disposed at the imaging surface.

[0125] Table 5 shows the curvature radius R, thickness d / distance T, refractive index ND, and Abbe number Vd of each lens of the fixed-focus lens of Example 3.

[0126]

[0127] Table 5

[0128] In this embodiment, the aperture number FNO of the fixed-focus lens is 1.05, the total image height H is 12.96 mm, and the total optical length TTL is 30.15 mm.

[0129] In this embodiment, the object side surface and the image side surface 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 the formula (1) given in the above embodiment 1. Table 6 shows the cone coefficient k and the high-order coefficients A4, A6, A8, A9 and A10 of each aspherical mirror surface S1-S4, S6-S9, S16-S19 that can be used in this embodiment. 10 , A 12 and A 14 .

[0130] Face number 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

[0131] Table 6

[0132] Example 4

[0133] Figure 4 The structure diagram of the fixed focus lens according to Embodiment 4 of the present application is shown below. Figure 4 A fixed-focus lens according to Embodiment 4 of the present application is described.

[0134] like Figure 4 As shown, the fixed focus lens includes, from the object side to the image side along the optical axis, a first lens L1, a second lens L2, an aperture 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 imaging surface (IMA). The sixth lens L6, the seventh lens L7, and the eighth lens L8 are cemented together to form a triplet lens group.

[0135] In this embodiment, the first lens L1 has negative power, and its object side surface S1 is concave, and its image side surface S2 is concave. The second lens L2 has positive power, and its object side surface S3 is concave, and its image side surface S4 is convex. The third lens L3 has negative power, and its object side surface S6 is concave, and its image side surface S7 is concave. The fourth lens L4 has positive power, and its object side surface S8 is convex, and its image side surface S9 is convex. The fifth lens L5 has positive power, and its object side surface S10 is convex, and its image side surface S11 is convex. The sixth lens L6 has positive power, and its object side surface S12 is convex, and its image side surface S13 is convex. The seventh lens L7 has negative power, and its object side surface S13 is concave, and its image side surface S14 is concave. The eighth lens L8 has positive power, and its object side surface S14 is convex, and its image side surface S15 is convex. The ninth lens L9 has negative refractive power, its object-side surface S16 is concave, and its image-side surface S17 is convex. The tenth lens L10 has positive refractive power, its object-side surface S18 is convex, and its image-side surface S19 is concave.

[0136] In this embodiment, the stop STO of the fixed focus lens is disposed between the second lens L2 and the third lens L3.

[0137] 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 may, for example, sequentially pass through the surfaces S1 to S21 and finally be imaged on the imaging surface S22, where an image sensor chip IMA may be disposed at the imaging surface.

[0138] Table 7 shows the curvature radius R, thickness d / distance T, refractive index ND, and Abbe number Vd of each lens of the fixed-focus lens of Example 4.

[0139]

[0140] Table 7

[0141] In this embodiment, the fixed-focus lens has an aperture number FNO=1.08, a full image height H=12.93 mm, and a total optical length TTL=30.00 mm.

[0142] In this embodiment, the object side surface and the image side surface 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 the formula (1) given in the above embodiment 1. Table 8 shows the cone coefficient k and the high-order coefficients A4, A6, A8, A9 and A10 of each aspherical mirror surface S1-S4, S6-S9, S16-S19 that can be used in this embodiment. 10 , A 12 and A 14 .

[0143]

[0144]

[0145] Table 8

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

[0147] Conditional formula\Example Example 1 Example 2 Example 3 Example 4 F / TTL 0.245 0.241 0.263 0.247 TTL / BFL 6.134 6.187 6.030 6.250 F1 / F -1.993 -2.085 -1.672 -2.039 F2 / F -21.731 -31.981 -12.680 5.203 T12 / TTL 0.119 0.142 0.107 0.091 F3 / F 9.438 -33.682 17.897 -2.229 ND2 / ND3 1.000 1.000 1.012 1.012 F4 / F 2.858 3.194 2.329 2.172 F5 / F 6.406 2.921 4.539 3.628 DM5 / TTL 0.400 0.399 0.433 0.414 F6 / F 1.532 1.259 1.312 1.666 F7 / F -0.882 -0.717 -0.741 -0.980 F8 / F 1.191 1.098 1.070 1.110 Fa / F 1.843 2.325 2.218 1.852 da / TTL 0.313 0.305 0.303 0.297 F9 / F -4.043 -2.750 -4.250 -1.690 F10 / F 5.479 3.836 5.717 2.147 F9 / F10 -0.738 -0.717 -0.743 -0.787 (R101+R102) / (R101-R102) -28.252 -9.371 -25.047 -4.688 ENPD / F 0.909 0.893 0.952 0.926

[0148] Table 9

[0149] The present application also provides an electronic device, which may include the fixed-focus lens according to the above-mentioned embodiment 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 only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with the technical features with similar functions disclosed in this application (but not limited to) by each other.

Claims

1. A fixed-focus lens, characterized in that: Along the optical axis from the object side to the image side, they include: a first lens having negative optical power; a second lens having optical power, wherein the object side surface is concave and the image side surface is convex; a third lens having optical power; a fourth lens having positive refractive power; a fifth lens element having positive refractive power and a convex image-side surface; a sixth lens having positive refractive power, whose object-side surface is convex and whose image-side surface is convex; The seventh lens element has a negative optical power, and its object side surface is concave and its image side surface is concave; an eighth lens having positive refractive power; a ninth lens element having negative optical power; and The tenth lens has positive refractive power, and its object side surface is convex and its image side surface is concave; Wherein, the sixth lens, the seventh lens and the eighth lens are a cemented triplet lens group.

2. The fixed-focus lens according to claim 1, characterized in that: The image side surface of the first lens is a concave surface; The object side surface of the fourth lens is convex, and the image side surface is convex; The object-side surface of the eighth lens is convex, and the image-side surface is convex; and The object side surface of the ninth lens is concave, and the image side surface is convex.

3. The fixed-focus lens according to claim 1 or 2, 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 surface of the first lens to the imaging surface of the fixed-focus lens on the optical axis satisfy: 0.23≤F / TTL≤0.

27.

4. The fixed-focus lens according to claim 1 or 2, characterized in that: A 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 and a distance BFL from the center of the image side surface of the tenth lens to the imaging surface on the optical axis satisfy: 5.9≤TTL / BFL≤6.

3.

5. The fixed-focus lens according to claim 1 or 2, characterized in that: The effective focal length F1 of the first lens and the total effective focal length F of the fixed-focus lens satisfy: -2.2≤F1 / F≤-1.

5.

6. The fixed-focus lens according to claim 1 or 2, 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 claim 1 or 2, characterized in that: An air gap T12 between the first lens and the second lens on the optical axis and a 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: 0.08≤T12 / TTL≤0.

15.

8. The fixed-focus lens according to claim 1 or 2, 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: -34.5≤F3 / F≤18.

5.

9. The fixed-focus lens according to claim 1 or 2, characterized in that: A refractive index ND2 of the second lens and a refractive index ND3 of the third lens satisfy: 0.95≤ND2 / ND3≤1.

05.

10. The fixed-focus lens according to claim 1 or 2, 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: 2.0≤F4 / F≤3.

4.

11. The fixed-focus lens according to claim 1 or 2, 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: 2.3≤F5 / F≤6.

5.

12. The fixed-focus lens according to claim 1 or 2, characterized in that: The maximum optical full aperture value DM5 of the object side surface and the image side surface of the fifth lens 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: 0.38≤DM5 / TTL≤0.

44.

13. The fixed-focus lens according to claim 1 or 2, 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: 1.15≤F6 / F≤1.

75.

14. The fixed-focus lens according to claim 1 or 2, 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: -1.1≤F7 / F≤-0.

6.

15. The fixed-focus lens according to claim 1 or 2, 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: 0.9≤F8 / F≤1.

5.

16. The fixed-focus lens according to claim 1 or 2, characterized in that: 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 the following: 1.8≤Fa / F≤4.

5.

17. The fixed-focus lens according to claim 1 or 2, characterized in that: The sum da of the center 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 surface of the first lens to the imaging surface of the fixed focus lens on the optical axis satisfy: 0.25≤da / TTL≤0.

33.

18. The fixed-focus lens according to claim 1 or 2, 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: -4.5≤F9 / F≤-1.

5.

19. The fixed-focus lens according to claim 1 or 2, 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: 1.9≤F10 / F≤5.

8.

20. The fixed-focus lens according to claim 1 or 2, characterized in that: The effective focal length F9 of the ninth lens and the effective focal length F10 of the tenth lens satisfy: -1.35≤F9 / F10≤-0.

6.

21. The fixed-focus lens according to claim 1 or 2, characterized in that: A curvature radius R101 of the object-side surface of the tenth lens and a curvature radius R102 of the image-side surface of the tenth lens satisfy: -29≤(R101+R102) / (R101-R102)≤-3.

22. The fixed-focus lens according to claim 1 or 2, characterized in that: An entrance pupil diameter ENPD of the fixed-focus lens and a total effective focal length F of the fixed-focus lens satisfy the following: 0.85≤ENPD / F≤0.98.

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