Prime lens

Abstract

The invention discloses a prime lens. The prime lens sequentially comprises a first lens, a second lens, a third lens, a fourth lens and a fifth 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 object side surface of the third lens is a convex surface, and the image side surface of the third lens is a convex surface; the object side surface of the fourth lens is a concave surface, and the image side surface of the fourth lens is a convex surface; the object side surface of the fifth lens is a concave surface, and the image side surface of the fifth lens is a concave surface; the sixth lens has positive focal power; a seventh lens with focal power; the eighth lens has focal power; the ninth lens has focal power; and the tenth lens has focal power. The number of the lenses with focal power in the prime lens is ten. The prime lens meets the conditional expression that (f2 + f3) / f is larger than or equal to-2.43 and smaller than or equal to-0.45, f2 is the effective focal length of the second lens, f3 is the effective focal length of the third lens, and f is the total effective focal length of the prime lens.

Description

Technical Field

[0001] This application relates to the field of optical components, and more specifically, to a fixed-focus lens. Background Technology

[0002] As people's awareness of security continues to increase, more and more optical lenses are being used in security monitoring and smart home systems, which in turn puts forward higher and higher requirements on the size, aperture, pixel resolution, and other aspects of optical lenses.

[0003] Currently, to ensure good nighttime imaging, optical lenses not only need clear image quality, but also require larger apertures and superior image quality. However, current optical lenses generally have large aperture values, and the image resolution of large-aperture lenses on the market is often not high; at the same time, the field of view of optical lenses is generally small, and the target surface size they are adapted to is also small, making it difficult to meet the current market demand.

[0004] Therefore, this application addresses the shortcomings of the prior art by providing a fixed-focus lens that can satisfy one of the following characteristics: large aperture, large field of view, large target surface, low cost, and 4K high resolution. Summary of the Invention

[0005] This application provides a fixed-focus lens, which comprises, along the optical axis from the object side to the image side, the following elements in sequence: a first lens with negative optical power; a second lens with negative optical power, wherein the object side is concave and the image side is convex; a third lens with positive optical power, wherein the object side is convex and the image side is convex; a fourth lens with optical power, wherein the object side is concave and the image side is convex; a fifth lens with negative optical power, wherein the object side is concave and the image side is concave; a sixth lens with positive optical power; a seventh lens with optical power; an eighth lens with optical power; a ninth lens with optical power; and a tenth lens with optical power. The fixed-focus lens satisfies the following condition: -2.43 ≤ (f2 + f3) / f ≤ -0.45, where f2 is the effective focal length of the second lens, f3 is the effective focal length of the third lens, and f is the total effective focal length of the fixed-focus lens. The fixed-focus lens contains ten lenses with optical power.

[0006] According to an exemplary embodiment of this application, the fourth lens has positive optical power, the seventh lens has negative optical power, the eighth lens has positive optical power, the ninth lens has negative optical power, and the tenth lens has positive optical power.

[0007] According to an exemplary embodiment of this application, the fourth lens has negative optical power, the seventh lens has positive optical power, the eighth lens has negative optical power, the ninth lens has positive optical power, and the tenth lens has negative optical power.

[0008] According to an exemplary embodiment of this application, the object-side surface of the first lens is convex, and the image-side surface is concave; the object-side surface of the sixth lens is convex, and the image-side surface is convex; the object-side surface of the seventh lens is convex, and the image-side surface is either convex or concave; the object-side surface of the eighth lens is convex, and the image-side surface is either convex or concave; the object-side surface of the ninth lens is either convex or concave, and the image-side surface is either convex or concave; the object-side surface of the tenth lens is either convex or concave, and the image-side surface is concave.

[0009] According to an exemplary embodiment of this application, the fifth lens and the sixth lens are cemented together to form a first cemented lens group; the seventh lens and the eighth lens are cemented together to form a second cemented lens group; or the eighth lens and the ninth lens are cemented together to form a second cemented lens group.

[0010] According to an exemplary embodiment of this application, the fixed-focus lens satisfies at least one of the following conditions: -2.49≤f1 / f≤-1.85, -6.68≤(f1+f2) / f≤-4.09, 1.52≤f34 / f≤3.42, -2.66≤f5 / f≤-1.62, 1.42≤f6 / f≤2.34, 2.86≤|f7 / f|≤7.45, 1.60≤|f8 / f|≤5.31, 1.47≤|f9 / f|≤ 3.55, 2.33≤|f10 / f|≤4.88, where f1 is the effective focal length of the first lens, f2 is the effective focal length of the second lens, f34 is the combined effective focal length of the third and fourth lenses, f5 is the effective focal length 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, f9 is the effective focal length of the ninth lens, f10 is the effective focal length of the tenth lens, and f is the total effective focal length of the fixed-focus lens.

[0011] According to an exemplary embodiment of this application, the fixed-focus lens satisfies at least one of the following conditions: 3.89 ≤ fB1 / f ≤ 12.96, 2.22 ≤ fB2 / f ≤ 3.04, 1.50 ≤ fB1 / fB2 ≤ 5.10, 0.39mm -1 ≤|Vd_B1| / fB1≤1.21mm -1 2.19mm -1 ≤|Vd_B2| / fB2≤3.14mm -1 Where fB1 is the effective focal length of the first cemented lens group, fB2 is the effective focal length of the second cemented lens group, f is the total effective focal length of the fixed-focus lens, Vd_B1 is the difference in Abbe number between the two lenses in the first cemented lens group, and Vd_B2 is the difference in Abbe number between the two lenses in the second cemented lens group.

[0012] According to an exemplary embodiment of this application, the fixed-focus lens satisfies the following condition: -0.05≤(R22+R31) / (R22-R31)≤0.03, where R31 is the radius of curvature of the object side of the third lens and R22 is the radius of curvature of the image side of the second lens.

[0013] According to an exemplary embodiment of this application, a fixed-focus lens satisfies the following condition: 5.50≤TTL / f≤7.67, where f is the total effective focal length of the fixed-focus lens and TTL is the total optical length of the fixed-focus lens.

[0014] According to an exemplary embodiment of this application, the fixed-focus lens satisfies at least one of the following conditions: -2.26≤f1 / f≤-2.05, -6.08≤(f1+f2) / f≤-4.55, -2.21≤(f2+f3) / f≤-0.50, 1.68≤f34 / f≤3.11, -2.42≤f5 / f≤-1.80, 1.58≤f6 / f≤2.13, 3.18≤|f7 / f|≤6.77, 1.78≤|f8 / f|≤4.83, 1.63≤|f9 / f|≤3.23, 2.59≤ |f10 / f|≤4.43, 6.11≤TTL / f≤6.98, where f1 is the effective focal length of the first lens, f2 is the effective focal length of the second lens, f3 is the effective focal length of the third lens, f34 is the combined effective focal length of the third and fourth lenses, f5 is the effective focal length 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, f9 is the effective focal length of the ninth lens, f10 is the effective focal length of the tenth lens, f is the total effective focal length of the fixed-focus lens, and TTL is the total optical length of the fixed-focus lens.

[0015] According to an exemplary embodiment of this application, the fixed-focus lens satisfies at least one of the following conditions: 4.32≤fB1 / f≤11.78, 2.47≤fB2 / f≤2.77, 1.67≤fB1 / fB2≤4.64, 0.43mm -1 ≤|Vd_B1| / fB1≤1.10mm -1 2.43mm -1 ≤|Vd_B2| / fB2≤2.85mm -1 Where fB1 is the effective focal length of the first cemented lens group, fB2 is the effective focal length of the second cemented lens group, f is the total effective focal length of the fixed-focus lens, Vd_B1 is the difference in Abbe number between the two lenses in the first cemented lens group, and Vd_B2 is the difference in Abbe number between the two lenses in the second cemented lens group.

[0016] The fixed-focus lens of this application achieves the following characteristics by reasonably setting the number of lenses (e.g., ten), reasonably allocating the optical power of each lens, and optimizing the surface shape of each lens: large aperture (Fno≤0.9), large field of view (FOV≥112°), large target surface (compatible with 1 / 1.8” chips), 4K high resolution, miniaturization (TTL≤38.20mm), low cost, and good thermal stability. Attached Figure Description

[0017] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0018] Figure 1 This is a schematic diagram of the fixed-focus lens according to Embodiment 1 of this application;

[0019] Figure 2 This is a schematic diagram of the fixed-focus lens according to Embodiment 2 of this application;

[0020] Figure 3 This is a schematic diagram of the fixed-focus lens according to Embodiment 3 of this application;

[0021] Figure 4 This is a schematic diagram of the fixed-focus lens according to Embodiment 4 of this application;

[0022] Figure 5 This is a schematic diagram of the fixed-focus lens according to Embodiment 5 of this application. Detailed Implementation

[0023] To better understand this application, various aspects of this application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely illustrative of exemplary embodiments of this application and are not intended to limit the scope of this application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0024] It should be noted that in this specification, the terms "first," "second," "third," etc., are used only to distinguish one feature from another and do not imply any limitation on the features. Therefore, without departing from the teachings of this application, the first lens discussed below may also be referred to as the second lens or the third lens.

[0025] In the accompanying drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustrative purposes only and are not strictly to scale.

[0026] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of the convexity is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the location of the concaveness is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the subject is called the object-side surface of the lens, and the surface of each lens closest to the imaging plane is called the image-side surface of the lens.

[0027] It should also be understood that the terms "comprising," "having," "including," etc., when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. Furthermore, when a statement such as "at least one of..." appears after a list of listed features, it modifies the entire list of features, not individual elements in the list. Additionally, when describing embodiments of this application, the word "may" is used to indicate "one or more embodiments of this application." And the term "exemplary" is intended to refer to an example or illustration.

[0028] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms (e.g., those defined in common dictionaries) shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formalized sense, unless expressly so specified herein.

[0029] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0030] According to an exemplary embodiment of this application, a fixed-focus lens may include ten lenses of optical power sequentially along the optical axis from the object side to the image side, 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.

[0031] In an exemplary embodiment, the first lens of the fixed-focus lens has negative optical power, with a convex object-side surface and a concave image-side surface. This configuration effectively converges incident light rays, diffusing the large field-of-view light rays entering the optical system to the rear optical system, effectively increasing the light transmission and achieving a large field of view. Simultaneously, it helps reduce the incident angle of the incident light rays on the object-side surface of the first lens, resulting in a smoother light transition and reducing the aberration correction burden on the rear lenses of the optical system.

[0032] In an exemplary embodiment, the second lens of the fixed-focus lens has negative optical power, with a concave object-side surface and a convex image-side surface. This configuration facilitates control of light path, ensuring a smooth transition of light, effectively correcting aberrations, and improving lens resolution. Simultaneously, it effectively controls the height of light transmission, elevating the light source and further ensuring a larger aperture before the light enters the aperture stop. This allows the light to pass through the aperture stop more effectively to the rear of the optical system, increasing light transmission and achieving a large aperture for the fixed-focus lens.

[0033] In an exemplary embodiment, the third lens of the fixed-focus lens has positive optical power, and both the object-side and image-side surfaces of the third lens are convex. This configuration effectively controls the direction of light, converges the light, reduces the angle of incidence of light entering the object-side surface of the third lens, effectively balances the aberrations caused by light passing through the aperture stop, improves image quality, and also helps to achieve a large aperture in the lens.

[0034] In an exemplary embodiment, the fourth lens of the fixed-focus lens has positive or negative optical power, and the object-side surface of the fourth lens is concave while the image-side surface is convex. This arrangement can further and more effectively control the direction of light, reduce the exit angle of light, help reduce the tolerance sensitivity between lenses, balance aberrations, and improve lens image quality.

[0035] In an exemplary embodiment, the fifth lens of the fixed-focus lens has negative optical power, and both the object-side and image-side surfaces of the fifth lens are concave. This configuration effectively controls the direction of light, which is beneficial for correcting aberrations and improving lens resolution.

[0036] In an exemplary embodiment, the sixth lens of the fixed-focus lens has positive optical power, and both its object-side and image-side surfaces are convex. This arrangement effectively converges light, which helps to reduce the aperture of the rear lens and also helps to shorten the air gap between the sixth and seventh lenses, thus contributing to lens miniaturization.

[0037] In an exemplary embodiment, the fifth and sixth lenses of the fixed-focus lens can form a first cemented lens group. By combining negative and positive optical powers to form the first cemented lens group, it is beneficial to smoothly transmit light, reduce the tolerance sensitivity of the lens, effectively correct chromatic aberration and aberration of the optical system, effectively reduce the risk of ghosting, and improve the resolution quality of the lens; in addition, it is also beneficial to achieve stable optical performance of the lens under high and low temperature conditions.

[0038] In an exemplary embodiment, the seventh lens of the fixed-focus lens has negative optical power, with a convex object-side surface and a concave image-side surface; the eighth lens of the fixed-focus lens has positive optical power, with a convex object-side surface and a convex image-side surface. As an example, the seventh and eighth lenses can form a second cemented lens group. This arrangement effectively controls the light path, reduces the light transmission height, and ensures the light height at the rear of the optical system, enabling the lens to effectively match a 1 / 1.8” large target chip. It also helps to shorten the air gap between the rear lenses, achieving lens miniaturization; furthermore, it effectively corrects system chromatic aberration and aberrations, improving image quality; and simultaneously ensures stable optical performance of the lens under high and low temperature conditions.

[0039] In an exemplary embodiment, the seventh lens of the fixed-focus lens has positive optical power, and both the object-side and image-side surfaces of the seventh lens are convex. This arrangement effectively controls the direction of light, allowing for a smooth transition of light rays, and effectively reduces the air gap between the seventh and eighth lenses, which helps save space and achieve lens miniaturization.

[0040] In an exemplary embodiment, the eighth lens of the fixed-focus lens has negative optical power, with a convex object-side surface and a concave image-side surface; the ninth lens of the fixed-focus lens has positive optical power, with a convex object-side surface and a convex image-side surface. As an example, the eighth and ninth lenses can form a second cemented lens group. This arrangement effectively controls the light path, reduces the light transmission height, and ensures the light height at the rear of the optical system, enabling the lens to effectively match a 1 / 1.8” large target chip. It also helps to shorten the air gap between the rear lenses, achieving lens miniaturization; furthermore, it effectively corrects system chromatic aberration and aberrations, improving image quality; and simultaneously ensures stable optical performance of the lens under high and low temperature conditions.

[0041] In an exemplary embodiment, the ninth lens of the fixed-focus lens has negative optical power, and both the object-side and image-side surfaces of the ninth lens are concave. This configuration effectively controls the direction of light, smoothly transmits light, ensures the light level at the rear of the optical system, and enables the lens to effectively match the 1 / 1.8” large target chip.

[0042] In an exemplary embodiment, the tenth lens of the fixed-focus lens has a positive optical power, and the object-side surface of the tenth lens is convex while the image-side surface is concave. When the tenth lens has a positive optical power, it can be paired with the ninth lens, which has a negative optical power, to further adjust the trajectory of light rays at the end of the optical system, ensuring the height of light rays transmitted to the imaging plane. This is beneficial for achieving a large target area of ​​the lens and also for achieving high illumination of the optical system.

[0043] In an exemplary embodiment, the tenth lens of the fixed-focus lens has a negative optical power, and the object-side and image-side surfaces of the tenth lens are concave. When the tenth lens has a negative optical power, it can be paired with a ninth lens that has a positive optical power, enabling peripheral large-angle light rays to transition as smoothly as possible to the rear optical system, correcting residual field curvature and astigmatism, and improving resolving power; at the same time, it can ensure the height of the light rays at the end of the optical system, which is beneficial for achieving a large target surface.

[0044] In an exemplary embodiment, the fixed-focus lens satisfies: -2.49 ≤ f1 / f ≤ -1.85, 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, the incident light rays are effectively converged, and the large field-of-view light rays entering the optical system are diverged to the rear of the optical system. This effectively expands the field of view, increases the amount of light transmitted, and achieves the characteristic of a large field of view. At the same time, it helps to reduce the incident angle of the incident light rays on the object side of the first lens, making the light transition smoother and reducing the aberration correction pressure on the rear lenses of the optical system. For example, the fixed-focus lens may also satisfy -2.26 ≤ f1 / f ≤ -2.05.

[0045] In an exemplary embodiment, the fixed-focus lens satisfies: -6.68 ≤ (f1 + f2) / f ≤ -4.09, where f1 is the effective focal length of the first lens, 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 sum of the effective focal lengths of the first and second lenses to the total effective focal length of the fixed-focus lens, the incident light rays are effectively converged, and the wide field of view light entering the optical system is diverged to the rear of the optical system, which can effectively expand the field of view. At the same time, it can further ensure that the light has a larger aperture before entering the aperture stop, so that the light can be better transmitted to the rear of the optical system through the aperture stop, increasing the amount of light transmitted and realizing the large aperture of the fixed-focus lens. For example, the fixed-focus lens can also satisfy -6.08 ≤ (f1 + f2) / f ≤ -4.55.

[0046] In an exemplary embodiment, the fixed-focus lens satisfies: -2.43 ≤ (f2 + f3) / f ≤ -0.45, where f2 is the effective focal length of the second lens, f3 is the effective focal length of the third lens, and f is the total effective focal length of the fixed-focus lens. By reasonably controlling the ratio of the sum of the effective focal lengths of the second and third lenses to the total effective focal length of the fixed-focus lens, the light path is effectively controlled, resulting in a smooth transition of light, effectively correcting aberrations, and improving the lens's resolution. Simultaneously, the height of light transmission is effectively controlled, elevating the light source and further ensuring a larger aperture before the light enters the aperture stop, allowing the light to pass better through the aperture stop to the rear of the optical system, increasing the amount of light transmitted, and achieving a large aperture for the fixed-focus lens. For example, the fixed-focus lens may also satisfy -2.21 ≤ (f2 + f3) / f ≤ -0.50.

[0047] In an exemplary embodiment, the fixed-focus lens satisfies: 1.52 ≤ f34 / f ≤ 3.42, where f34 is the combined effective focal length of the third and fourth lenses, and f is the total effective focal length of the fixed-focus lens. By reasonably controlling the ratio of the combined effective focal length of the third and fourth lenses to the total effective focal length of the fixed-focus lens, the direction of light can be effectively controlled, resulting in a smooth transition of light and reducing the tolerance sensitivity between the third and fourth lenses, thus helping to improve the lens's production yield. Simultaneously, it also helps to reduce spherical aberration and improve the lens's image quality. For example, the fixed-focus lens may also satisfy 1.68 ≤ f34 / f ≤ 3.11.

[0048] In an exemplary embodiment, the fixed-focus lens satisfies: -2.66 ≤ f5 / f ≤ -1.62, 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 reasonably controlling the ratio of the effective focal length of the fifth lens to the total effective focal length of the fixed-focus lens, the direction of light can be effectively controlled, which is beneficial for correcting aberrations and chromatic aberrations, reducing the risk of ghosting, and improving the lens's resolving quality. For example, the fixed-focus lens may also satisfy -2.42 ≤ f5 / f ≤ -1.80.

[0049] In an exemplary embodiment, the fixed-focus lens satisfies: 1.42 ≤ f6 / f ≤ 2.34, where f is the total effective focal length of the fixed-focus lens and f6 is the effective focal length of the sixth lens. By reasonably controlling the ratio of the effective focal length of the sixth lens to the total effective focal length of the fixed-focus lens, light can be effectively converged, which is beneficial for reducing the aperture of the rear lens and shortening the air gap between the sixth and seventh lenses, thus contributing to lens miniaturization. For example, the fixed-focus lens may also satisfy 1.58 ≤ f6 / f ≤ 2.13.

[0050] In an exemplary embodiment, the fixed-focus lens satisfies: 2.86 ≤ |f7 / f| ≤ 7.45, 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 reasonably controlling the ratio of the effective focal length of the seventh lens to the total effective focal length of the fixed-focus lens, the direction of light is effectively controlled, the transmission height of light is reduced, the light height at the rear end of the optical system is guaranteed, the light is transmitted smoothly, the system chromatic aberration and aberration are effectively corrected, and the image quality is improved; at the same time, the lens maintains stable optical performance under high and low temperature conditions. Exemplarily, the fixed-focus lens may also satisfy 3.18 ≤ |f7 / f| ≤ 6.77.

[0051] In an exemplary embodiment, the fixed-focus lens satisfies: 1.60 ≤ |f8 / f| ≤ 5.31, 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 appropriately setting the ratio of the effective focal length of the eighth lens to the total effective focal length of the fixed-focus lens, the light path can be effectively controlled, and the light transmission height can be reduced. This ensures the light height at the rear of the optical system, allowing the lens to effectively match the 1 / 1.8” large target surface chip. It also helps to shorten the air gap of the rear lens, achieving lens miniaturization. Furthermore, it effectively corrects system chromatic aberration and aberrations, improving image quality. For example, the fixed-focus lens may also satisfy 1.78 ≤ |f8 / f| ≤ 4.83.

[0052] In an exemplary embodiment, the fixed-focus lens satisfies: 1.47 ≤ |f9 / f| ≤ 3.55, where f9 is the effective focal length of the ninth lens and f is the total effective focal length of the fixed-focus lens. Reasonably controlling the ratio of the effective focal length of the ninth lens to the total effective focal length of the fixed-focus lens can effectively control the light path, smoothly transmit light, ensure the light level at the rear of the optical system, and enable the lens to effectively match the 1 / 1.8” large target surface chip; it also helps to eliminate residual high-order aberrations in the optical system and improve the lens's resolving power. For example, the fixed-focus lens can also satisfy 1.63 ≤ |f9 / f| ≤ 3.23.

[0053] In an exemplary embodiment, the fixed-focus lens satisfies: 2.33 ≤ |f10 / f| ≤ 4.88, where f10 is the effective focal length of the tenth lens, and f is the total effective focal length of the fixed-focus lens. Reasonably controlling the ratio of the effective focal length of the tenth lens to the total effective focal length of the fixed-focus lens helps eliminate residual higher-order aberrations in the optical system and improves lens resolving power; it also helps to effectively match the lens with a 1 / 1.8” large-area chip, achieving a large-area effect. Exemplarily, the fixed-focus lens may also satisfy 2.59 ≤ |f10 / f| ≤ 4.43.

[0054] In an exemplary embodiment, the fixed-focus lens satisfies: 3.89 ≤ fB1 / f ≤ 12.96, where fB1 is the effective focal length of the first cemented lens group, and f is the total effective focal length of the fixed-focus lens. Reasonably controlling the ratio of the effective focal length of the first cemented lens group to the total effective focal length of the fixed-focus lens helps to smoothly transmit light, reduce the lens's tolerance sensitivity, effectively correct chromatic aberration and aberrations in the optical system, effectively reduce the risk of ghosting, and improve the lens's resolving quality. Furthermore, it helps to ensure stable optical performance of the lens under high and low temperature conditions. For example, the fixed-focus lens may also satisfy 4.32 ≤ fB1 / f ≤ 11.78.

[0055] In an exemplary embodiment, the fixed-focus lens satisfies: 2.22 ≤ fB2 / f ≤ 3.04, where fB2 is the effective focal length of the second cemented lens group, 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 cemented lens group to the total effective focal length of the fixed-focus lens, the direction of light can be effectively controlled, the light transmission height can be reduced, and the light height at the rear of the optical system can be guaranteed, allowing the lens to effectively match the 1 / 1.8” large target chip. It also helps to shorten the air gap of the rear lens, achieving lens miniaturization. Furthermore, it effectively corrects system chromatic aberration and aberrations, improving image quality. For example, the fixed-focus lens may also satisfy 2.47 ≤ fB2 / f ≤ 2.77.

[0056] In an exemplary embodiment, the fixed-focus lens satisfies: 1.50 ≤ fB1 / fB2 ≤ 5.10, where fB1 is the effective focal length of the first cemented lens group and fB2 is the effective focal length of the second cemented lens group. Reasonably controlling the ratio of the effective focal lengths of the first and second cemented lens groups can effectively allocate the optical power of the two groups, which is beneficial for smooth light transmission, reducing the lens's tolerance sensitivity, and effectively correcting chromatic aberration and aberrations in the optical system, effectively reducing the risk of ghosting and improving the lens's resolving quality. For example, the fixed-focus lens can also satisfy 1.67 ≤ fB1 / fB2 ≤ 4.64.

[0057] In an exemplary embodiment, the fixed-focus lens satisfies: -0.05 ≤ (R22 + R31) / (R22 - R31) ≤ 0.03, where R31 is the radius of curvature of the object-side surface of the third lens, and R22 is the radius of curvature of the image-side surface of the second lens. Reasonably controlling the radii of curvature of the object-side surface of the third lens and the image-side surface of the second lens is beneficial for adjusting the radii of curvature of the lens surfaces before and after the aperture stop, effectively controlling the light path, allowing the light to pass through the aperture stop smoothly, which helps increase the amount of light transmitted and achieve a large aperture effect; at the same time, it can also reduce the aberrations generated when light passes through the aperture stop, which is beneficial for clear imaging.

[0058] In an exemplary embodiment, the fixed-focus lens satisfies: 5.50 ≤ TTL / f ≤ 7.67, where TTL is the total optical length of the fixed-focus lens, and f is the total effective focal length of the fixed-focus lens. Under a given system focal length value, controlling the total optical length of the system results in a smaller overall optical length, which is beneficial for achieving a compact size. For example, the fixed-focus lens may also satisfy 6.11 ≤ TTL / f ≤ 6.98.

[0059] In an exemplary embodiment, the fixed-focus lens satisfies: 0.39mm -1 ≤|Vd_B1| / fB1≤1.21mm -1Where fB1 is the effective focal length of the first cemented lens group, and Vd_B1 is the difference in Abbe numbers between the two lenses in the first cemented lens group. By appropriately selecting the lens material of the first cemented lens group and reasonably controlling the ratio of the difference in Abbe numbers between the two lenses in the first cemented lens group to the effective focal length of the first cemented lens group, it is beneficial to correct chromatic aberration and eliminate higher-order aberrations generated by the rear lens, thereby improving the image quality of the lens and achieving 4K high resolution. For example, a fixed-focus lens can also meet the 0.43mm requirement. -1 ≤|Vd_B1| / fB1≤1.10mm -1 .

[0060] In an exemplary embodiment, the fixed-focus lens satisfies: 2.19mm. -1 ≤|Vd_B2| / fB2≤3.14mm -1 Where fB2 is the effective focal length of the second cemented lens group, and Vd_B2 is the difference in Abbe numbers between the two lenses in the second cemented lens group. By appropriately selecting the lens material of the second cemented lens group and reasonably controlling the ratio of the difference in Abbe numbers between the two lenses in the second cemented lens group to the effective focal length of the second cemented lens group, it is beneficial to correct chromatic aberration and eliminate residual higher-order aberrations in the optical system, thereby improving the image quality of the lens and achieving 4K high resolution. For example, a fixed-focus lens can also meet the 2.43mm requirement. -1 ≤|Vd_B2| / fB2≤2.85mm -1 .

[0061] In exemplary embodiments, this application utilizes a combination of spherical and aspherical lenses, which helps reduce the manufacturing difficulty of the lenses; simultaneously, through material selection, a heat-free design can be achieved. This application does not specifically limit the number of spherical and aspherical lenses. When image quality is the primary focus, the number of aspherical lenses can be increased, or even all lenses can be aspherical. Aspherical lenses are characterized by a continuously changing curvature from the lens center to the periphery. Unlike spherical lenses, which have a constant curvature from the lens center to the periphery, aspherical lenses have better radius of curvature characteristics, offering advantages in improving distortion and astigmatism. By using aspherical lenses, aberrations occurring during imaging can be eliminated as much as possible, thereby improving the image quality of the lens. However, those skilled in the art should understand that, without departing from the technical solutions claimed in this application, the lens surface type constituting the fixed-focus lens can be modified to obtain the various results and advantages described in this specification. For example, in this application, the first lens, the second lens, the third lens, the fourth lens and the tenth lens are all aspherical lenses, the fifth lens, the sixth lens and the eighth lens are spherical lenses, and the seventh lens and the ninth lens are either spherical lenses or aspherical lenses.

[0062] Those skilled in the art will understand that plastics have a large temperature coefficient of refractive index (dn / dt) and anomalous dispersion. A suitable amount of plastic material is beneficial for high and low temperature balance, but excessive plastic lenses are detrimental to system stability. Optical lenses made of glass can suppress the shift in back focus of the optical lens due to temperature changes, thereby improving system stability. Simultaneously, using glass avoids lens blurring caused by high and low temperature changes in the operating environment, thus preventing problems affecting the normal use of the lens. Using glass also facilitates heat-free lens operation. Furthermore, using glass can better correct system chromatic aberration, improve lens resolution, and reduce ghosting. As an example, in this application, the first, second, third, fourth, and tenth lenses are all made of plastic, the fifth, sixth, and eighth lenses are made of glass, and the seventh and ninth lenses are made of either glass or plastic. This arrangement allows for a wider temperature range for the fixed-focus lens. It maintains stable optical performance within a certain range.

[0063] In an exemplary embodiment, the total optical length (TTL) of the fixed-focus lens of this application can satisfy: TTL≤38.25mm, which results in a short total optical length, compact structure, and miniaturization of the lens. Exemplarily, the total optical length (TTL) of the fixed-focus lens can further satisfy: 35.10mm≤TTL≤38.21mm.

[0064] In an exemplary embodiment, the field of view (FOV) of the fixed-focus lens of this application can satisfy: FOV ≥ 112°, thereby increasing the shooting range of the fixed-focus lens and improving the practical application value of the product. For example, the FOV of the fixed-focus lens can further satisfy: 112° ≤ FOV ≤ 117°.

[0065] In an exemplary embodiment, the aperture number Fno of the fixed-focus lens of this application satisfies: Fno≤0.9. Further, Fno can satisfy: 0.8≤Fno≤0.9, which ensures that the fixed-focus lens has a large aperture characteristic, allowing the lens to have a large amount of light transmission.

[0066] The fixed-focus lens of this application may further include an aperture stop for limiting the light beam. The aperture stop helps to concentrate the light entering the fixed-focus lens, reduce the maximum aperture of the fixed-focus lens, and balance the off-axis aberrations of the optical system, thereby further improving the image quality of the fixed-focus lens. It should be noted that the aperture stop can be positioned between or to one side of any lens, depending on actual needs. For example, the aperture stop is positioned between the second and third lenses or on the image-side surface of the second lens.

[0067] The fixed-focus lens of this application has excellent resolving power. At a spatial frequency of 125 lp / mm, the MTF value of the center field of view can reach up to 0.78 and the MTF value of the peripheral field of view can reach up to 0.50, which can be used with a camera to achieve 4K high resolution.

[0068] The fixed-focus lens of this application does not lose focus within a temperature range of -40℃ to 80℃ and has stable optical performance under high and low temperature conditions.

[0069] Alternatively, in other alternative exemplary embodiments, the above-described fixed-focus lens may also be equipped with a filter for correcting color deviation and / or a protective glass for protecting the photosensitive element located on the imaging surface.

[0070] However, those skilled in the art will understand that the number of lenses constituting a fixed-focus lens can be varied to obtain the various results and advantages described herein without departing from the technical solutions claimed in this application. For example, although ten lenses are described as an example in the embodiments, the fixed-focus lens is not limited to including ten lenses. If desired, the fixed-focus lens may also include other numbers of lenses.

[0071] The following describes in further detail, with reference to the accompanying drawings, specific embodiments of a fixed-focus lens applicable to the above-described embodiments.

[0072] Example 1

[0073] Figure 1 A schematic diagram of the fixed-focus lens according to Embodiment 1 of this application is shown. Figure 1 As shown, the fixed-focus lens includes, in sequence from the object side to the image side, a first lens L1, a second lens L2, 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, and a tenth lens L10 along the optical axis.

[0074] The first lens L1 has negative optical power, with its object side S1 being convex and its image side S2 being concave.

[0075] The second lens L2 has negative optical power, with its object side S3 being concave and its image side S4 being convex.

[0076] The third lens L3 has positive optical power, and its object side S6 is convex, while its image side S7 is convex.

[0077] The fourth lens L4 has positive optical power, with its object side S8 being concave and its image side S9 being convex.

[0078] The fifth lens L5 has negative optical power, and its object side S10 is concave, and its image side S11 is concave.

[0079] The sixth lens L6 has positive optical power, and its object side S11 is convex, and its image side S12 is convex.

[0080] The seventh lens L7 has negative optical power, with its object side S13 being convex and its image side S14 being concave.

[0081] The eighth lens L8 has positive optical power, and its object side S14 is convex, and its image side S15 is convex.

[0082] The ninth lens L9 has negative optical power, and its object side S16 is concave, and its image side S17 is concave.

[0083] The tenth lens L10 has positive optical power, with its object side S18 being convex and its image side S19 being concave.

[0084] Fixed-focus lenses also include an aperture stop STO, which can be set between the second lens L2 and the third lens L3.

[0085] The fixed-focus lens may also include a filter (not shown) having an object-side side and an image-side side and / or a protective glass CG having an object-side side S20 and an image-side side S21. The filter can be used to correct color aberrations, and the protective glass CG can be used to protect the image sensor chip located at the imaging surface. Light from the object passes sequentially through each surface S1 to S21 and is finally imaged onto the imaging surface IMG. It should be noted that surfaces S1 to S21 are... Figure 1 Not shown in the image.

[0086] Table 1 shows the basic parameters of the fixed-focus lens of Example 1, where the units for radius of curvature and thickness / distance are millimeters (mm).

[0087] Table 1

[0088]

[0089]

[0090] In Example 1, the object-side and image-side surfaces of the first lens, second lens, third lens, fourth lens, ninth lens, and tenth lens are all aspherical. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formula:

[0091]

[0092] 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, A10 and A12 that can be used for each aspherical mirror in Example 1.

[0093] Table 2

[0094] Face number k A4 A6 A8 A10 A12 S1 -0.67 -2.51E-03 5.98E-05 -8.26E-07 6.07E-09 -1.58E-11 S2 -0.57 -4.19E-03 9.45E-05 -5.26E-06 2.09E-07 -5.15E-09 S3 -4.22 -8.31E-04 -1.21E-05 2.70E-06 -1.31E-07 1.80E-09 S4 1.33 2.12E-03 -1.08E-04 8.36E-06 -2.88E-07 4.56E-09 S6 -13.31 -6.00E-04 2.93E-05 -9.15E-07 1.82E-08 -1.79E-10 S7 -49.59 -1.05E-03 2.54E-05 -6.83E-07 1.59E-08 -1.62E-10 S8 2.63 -1.18E-04 4.06E-07 6.63E-08 6.08E-10 4.30E-12 S9 0.16 -1.16E-05 -1.41E-06 -1.24E-08 1.37E-11 9.26E-12 S16 20.96 1.40E-04 -1.96E-05 5.74E-07 -8.80E-09 5.51E-11 S17 0.84 -7.68E-06 -2.12E-05 7.36E-07 -1.29E-08 4.21E-11 S18 -1.61 9.53E-05 5.69E-06 1.23E-07 -3.28E-09 7.78E-11 S19 -46.26 -2.26E-05 2.72E-07 8.27E-07 -3.23E-08 7.65E-10

[0095] In this embodiment 1, the fixed-focus lens has an MTF value of 0.72 in the center field of view at a spatial frequency of 125 lp / mm, and the MTF value is above 0.42 in the entire field of view. Furthermore, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, indicating that the fixed-focus lens has good image quality and good detail resolution.

[0096] Example 2

[0097] Figure 2 A schematic diagram of the fixed-focus lens of Embodiment 2 of this application is shown. Figure 2 As shown, the fixed-focus lens includes, in sequence from the object side to the image side, a first lens L1, a second lens L2, 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, and a tenth lens L10 along the optical axis.

[0098] The first lens L1 has negative optical power, with its object side S1 being convex and its image side S2 being concave.

[0099] The second lens L2 has negative optical power, with its object side S3 being concave and its image side S4 being convex.

[0100] The third lens L3 has positive optical power, and its object side S5 is convex, while its image side S6 is convex.

[0101] The fourth lens L4 has negative optical power, with its object side S7 being concave and its image side S8 being convex.

[0102] The fifth lens L5 has negative optical power, and its object side S9 is concave, and its image side S10 is concave.

[0103] The sixth lens L6 has positive optical power, and its object side S10 is convex, and its image side S11 is convex.

[0104] The seventh lens L7 has positive optical power, and its object side S12 is convex, and its image side S13 is convex.

[0105] The eighth lens L8 has negative optical power, with its object side S14 being convex and its image side S15 being concave.

[0106] The ninth lens L9 has positive optical power, and its object side S15 is convex, and its image side S16 is convex.

[0107] The tenth lens L10 has negative optical power, and its object side S17 is concave, and its image side S18 is concave.

[0108] Fixed-focus lenses also include an aperture stop STO, which can be set on the image side of the second lens L2.

[0109] The fixed-focus lens may also include a filter (not shown) having an object-side side and an image-side side and / or a protective glass CG having an object-side side S19 and an image-side side S20. The filter can be used to correct color aberrations, and the protective glass CG can be used to protect the image sensor chip located at the imaging surface. Light from the object passes sequentially through each surface S1 to S20 and is finally imaged onto the imaging surface IMG. It should be noted that surfaces S1 to S20 are... Figure 2 Not shown in the image.

[0110] Table 3 shows the basic parameters of the fixed-focus lens in Example 2, where the units for radius of curvature and thickness / distance are millimeters (mm).

[0111] Table 3

[0112]

[0113]

[0114] In Example 2, the object-side and image-side surfaces of the first, second, third, fourth, seventh, and tenth lenses are all aspherical. The surface shape of each aspherical lens can be limited by, but is not limited to, the formula (1) given in Example 1 above. Table 4 below shows the conic coefficient k and higher-order coefficients A4, A6, A8, A10, and A12 that can be used for each aspherical mirror in Example 2.

[0115] Table 4

[0116] Face number k A4 A6 A8 A10 A12 S1 -0.55 -2.32E-03 4.11E-05 -6.21E-08 -9.20E-09 1.06E-10 S2 -0.67 -3.43E-03 7.34E-05 -5.63E-06 4.48E-07 -1.47E-08 S3 -6.86 1.68E-04 -4.75E-05 1.45E-06 -3.04E-08 -4.19E-09 S4 3.28 2.67E-03 -1.03E-04 8.34E-06 -3.58E-07 6.54E-09 S5 -17.48 -4.93E-04 3.59E-05 -8.13E-07 1.26E-08 -9.07E-11 S6 -6.87 -1.36E-03 3.39E-05 -5.72E-07 1.77E-08 -2.01E-10 S7 0.28 -6.47E-05 2.59E-06 2.35E-07 4.93E-10 -8.99E-11 S8 0.00 -8.70E-05 1.50E-07 1.57E-08 8.98E-10 -7.09E-12 S12 -1.32 -2.57E-04 -2.97E-07 -1.74E-08 6.27E-11 0.00E+00 S13 0.00 -1.84E-04 -7.26E-07 2.94E-09 -8.60E-11 0.00E+00 S17 2.59 -4.37E-04 1.26E-05 -2.23E-07 2.15E-09 2.76E-12 S18 0.00 -4.74E-04 7.18E-06 -3.36E-07 5.03E-09 2.39E-11

[0117] In this embodiment 2, the fixed-focus lens has an MTF value of 0.78 in the center field of view at a spatial frequency of 125 lp / mm, and the MTF value is above 0.50 in the entire field of view. Furthermore, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, indicating that the fixed-focus lens has good image quality and good detail resolution.

[0118] Example 3

[0119] Figure 3 A schematic diagram of the fixed-focus lens according to Embodiment 3 of this application is shown. Figure 3 As shown, the fixed-focus lens includes, in sequence from the object side to the image side, a first lens L1, a second lens L2, 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, and a tenth lens L10 along the optical axis.

[0120] The first lens L1 has negative optical power, with its object side S1 being convex and its image side S2 being concave.

[0121] The second lens L2 has negative optical power, with its object side S3 being concave and its image side S4 being convex.

[0122] The third lens L3 has positive optical power, and its object side S6 is convex, while its image side S7 is convex.

[0123] The fourth lens L4 has positive optical power, with its object side S8 being concave and its image side S9 being convex.

[0124] The fifth lens L5 has negative optical power, and its object side S10 is concave, and its image side S11 is concave.

[0125] The sixth lens L6 has positive optical power, and its object side S11 is convex, and its image side S12 is convex.

[0126] The seventh lens L7 has negative optical power, with its object side S13 being convex and its image side S14 being concave.

[0127] The eighth lens L8 has positive optical power, and its object side S14 is convex, and its image side S15 is convex.

[0128] The ninth lens L9 has negative optical power, and its object side S16 is concave, and its image side S17 is concave.

[0129] The tenth lens L10 has positive optical power, with its object side S18 being convex and its image side S19 being concave.

[0130] Fixed-focus lenses also include an aperture stop STO, which can be set between the second lens L2 and the third lens L3.

[0131] The fixed-focus lens may also include a filter (not shown) having an object-side side and an image-side side and / or a protective glass CG having an object-side side S20 and an image-side side S21. The filter can be used to correct color aberrations, and the protective glass CG can be used to protect the image sensor chip located at the imaging surface. Light from the object passes sequentially through each surface S1 to S21 and is finally imaged onto the imaging surface IMG. It should be noted that surfaces S1 to S21 are... Figure 3 Not shown in the image.

[0132] Table 5 shows the basic parameters of the fixed-focus lens of Example 3, where the units for radius of curvature and thickness / distance are millimeters (mm).

[0133] Table 5

[0134]

[0135] In Example 3, the object-side and image-side surfaces of the first, second, third, fourth, ninth, and tenth lenses are all aspherical. The surface shape of each aspherical lens can be defined by, but is not limited to, the formula (1) given in Example 1 above. Table 6 below shows the conic coefficient k and higher-order coefficients A4, A6, A8, A10, and A12 that can be used for each aspherical mirror in Example 3.

[0136] Table 6

[0137]

[0138]

[0139] In this embodiment 3, the fixed-focus lens has an MTF value of 0.73 in the center field of view at a spatial frequency of 125 lp / mm, and the MTF value is above 0.40 in the entire field of view. Furthermore, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, indicating that the fixed-focus lens has good image quality and good detail resolution.

[0140] Example 4

[0141] Figure 4 A schematic diagram of the fixed-focus lens of Embodiment 4 of this application is shown. Figure 4 As shown, the fixed-focus lens includes, in sequence from the object side to the image side, a first lens L1, a second lens L2, 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, and a tenth lens L10 along the optical axis.

[0142] The first lens L1 has negative optical power, with its object side S1 being convex and its image side S2 being concave.

[0143] The second lens L2 has negative optical power, with its object side S3 being concave and its image side S4 being convex.

[0144] The third lens L3 has positive optical power, and its object side S6 is convex, while its image side S7 is convex.

[0145] The fourth lens L4 has positive optical power, with its object side S8 being concave and its image side S9 being convex.

[0146] The fifth lens L5 has negative optical power, and its object side S10 is concave, and its image side S11 is concave.

[0147] The sixth lens L6 has positive optical power, and its object side S11 is convex, and its image side S12 is convex.

[0148] The seventh lens L7 has negative optical power, with its object side S13 being convex and its image side S14 being concave.

[0149] The eighth lens L8 has positive optical power, and its object side S14 is convex, and its image side S15 is convex.

[0150] The ninth lens L9 has negative optical power, and its object side S16 is concave, and its image side S17 is concave.

[0151] The tenth lens L10 has positive optical power, with its object side S18 being convex and its image side S19 being concave.

[0152] Fixed-focus lenses also include an aperture stop STO, which can be set between the second lens L2 and the third lens L3.

[0153] The fixed-focus lens may also include a filter (not shown) having an object-side side and an image-side side and / or a protective glass CG having an object-side side S20 and an image-side side S21. The filter can be used to correct color aberrations, and the protective glass CG can be used to protect the image sensor chip located at the imaging surface. Light from the object passes sequentially through each surface S1 to S21 and is finally imaged onto the imaging surface IMG. It should be noted that surfaces S1 to S21 are... Figure 4 Not shown in the image.

[0154] Table 7 shows the basic parameters of the fixed-focus lens of Example 4, where the units for radius of curvature and thickness / distance are millimeters (mm).

[0155] Table 7

[0156]

[0157] In Example 4, the object-side and image-side surfaces of the first, second, third, fourth, ninth, and tenth lenses are all aspherical. The surface shape of each aspherical lens can be defined using, but is not limited to, the formula (1) given in Example 1 above. Table 8 below shows the conic coefficient k and higher-order coefficients A4, A6, A8, A10, A12, and A14 that can be used for each aspherical mirror in Example 4.

[0158] Table 8

[0159] Face number k A4 A6 A8 A10 A12 A14 S1 -1.75 -2.80E-03 6.71E-05 -3.74E-07 -9.54E-09 1.45E-10 0.00E+00 S2 -0.69 -4.26E-03 9.52E-05 -2.59E-06 4.56E-08 4.83E-09 -1.56E-10 S3 -4.79 -6.02E-04 -2.03E-05 1.95E-06 -1.63E-07 6.06E-09 -1.02E-10 S4 1.52 2.15E-03 -1.05E-04 8.19E-06 -3.05E-07 6.06E-09 -1.53E-11 S6 -10.47 -5.13E-04 2.62E-05 -8.68E-07 1.99E-08 -2.33E-10 0.00E+00 S7 0.00 -1.01E-03 2.33E-05 -6.49E-07 1.65E-08 -1.94E-10 0.00E+00 S8 2.74 -2.74E-04 2.10E-06 6.14E-08 -2.14E-10 9.38E-12 0.00E+00 S9 -1.09 7.24E-05 -4.39E-06 9.25E-09 6.40E-10 3.30E-12 0.00E+00 S16 0.00 -7.00E-06 -1.79E-05 6.38E-07 -1.08E-08 6.86E-11 0.00E+00 S17 0.59 -2.08E-04 -1.54E-05 8.53E-07 -1.44E-08 2.28E-11 0.00E+00 S18 -1.87 7.33E-05 4.83E-06 -1.55E-07 5.05E-09 -2.33E-10 0.00E+00 S19 -9.43 -1.70E-04 -4.71E-06 -2.46E-07 7.40E-10 3.64E-11 0.00E+00

[0160] In this embodiment 4, the fixed-focus lens has an MTF value of 0.50 in the center field of view at a spatial frequency of 125 lp / mm, and the MTF value is above 0.20 in the entire field of view. Furthermore, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, indicating that the fixed-focus lens has good image quality and good detail resolution.

[0161] Example 5

[0162] Figure 5 A schematic diagram of the fixed-focus lens according to Embodiment 5 of this application is shown. Figure 5 As shown, the fixed-focus lens includes, in sequence from the object side to the image side, a first lens L1, a second lens L2, 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, and a tenth lens L10 along the optical axis.

[0163] The first lens L1 has negative optical power, with its object side S1 being convex and its image side S2 being concave.

[0164] The second lens L2 has negative optical power, with its object side S3 being concave and its image side S4 being convex.

[0165] The third lens L3 has positive optical power, and its object side S5 is convex, while its image side S6 is convex.

[0166] The fourth lens L4 has negative optical power, with its object side S7 being concave and its image side S8 being convex.

[0167] The fifth lens L5 has negative optical power, and its object side S9 is concave, and its image side S10 is concave.

[0168] The sixth lens L6 has positive optical power, and its object side S10 is convex, and its image side S11 is convex.

[0169] The seventh lens L7 has positive optical power, and its object side S12 is convex, and its image side S13 is convex.

[0170] The eighth lens L8 has negative optical power, with its object side S14 being convex and its image side S15 being concave.

[0171] The ninth lens L9 has positive optical power, and its object side S15 is convex, and its image side S16 is convex.

[0172] The tenth lens L10 has negative optical power, and its object side S17 is concave, and its image side S18 is concave.

[0173] Fixed-focus lenses also include an aperture stop STO, which can be set on the image side of the second lens L2.

[0174] The fixed-focus lens may also include a filter (not shown) having an object-side side and an image-side side and / or a protective glass CG having an object-side side S19 and an image-side side S20. The filter can be used to correct color aberrations, and the protective glass CG can be used to protect the image sensor chip located at the imaging surface. Light from the object passes sequentially through each surface S1 to S20 and is finally imaged onto the imaging surface IMG. It should be noted that surfaces S1 to S20 are... Figure 5 Not shown in the image.

[0175] Table 9 shows the basic parameters of the fixed-focus lens of Example 5, where the units for radius of curvature and thickness / distance are millimeters (mm).

[0176] Table 9

[0177]

[0178]

[0179] In Example 5, the object-side and image-side surfaces of the first, second, third, fourth, seventh, and tenth lenses are all aspherical. The surface shape of each aspherical lens can be defined by, but is not limited to, the formula (1) given in Example 1 above. Table 10 below gives the conic coefficient k and higher-order coefficients A4, A6, A8, A10, and A12 that can be used for each aspherical mirror in Example 5.

[0180] Table 10

[0181] Face number k A4 A6 A8 A10 A12 S1 -3.46 -2.24E-03 4.90E-05 -1.51E-07 -7.89E-09 8.92E-11 S2 -0.70 -3.95E-03 9.53E-05 -3.28E-06 7.59E-08 1.84E-09 S3 -8.05 -1.49E-04 -6.27E-05 2.17E-06 -7.65E-08 8.02E-10 S4 3.52 2.18E-03 -1.29E-04 8.91E-06 -3.20E-07 6.08E-09 S5 -16.07 -3.94E-04 2.76E-05 -9.25E-07 2.03E-08 -2.27E-10 S6 -8.45 -9.99E-04 2.49E-05 -5.88E-07 1.37E-08 -1.48E-10 S7 -0.28 5.39E-05 -3.57E-07 1.08E-07 1.16E-09 -1.34E-11 S8 1.13 -2.42E-05 -3.69E-07 -1.58E-09 1.00E-09 -3.51E-13 S12 -2.28 -2.92E-04 -8.69E-08 -1.22E-08 3.62E-10 -1.53E-12 S13 -38.46 -1.41E-04 1.96E-06 1.10E-08 1.33E-11 2.46E-12 S17 -43.92 2.66E-04 6.11E-06 -8.91E-08 -3.96E-11 4.58E-11 S18 61.31 2.49E-04 3.65E-06 -3.68E-07 6.37E-09 1.12E-10

[0182] In this embodiment 5, the fixed-focus lens has an MTF value of 0.64 in the center field of view at a spatial frequency of 125 lp / mm, and the MTF value is above 0.10 in the entire field of view. Furthermore, the MTF curve decreases smoothly and evenly from the center to the edge of the field of view, indicating that the fixed-focus lens has good image quality and good detail resolution.

[0183] In summary, the fixed-focus lenses in Examples 1 to 5 satisfy the relationships shown in Table 11. In each example, the unit for the parameter f regarding the fixed-focus lens is millimeters (mm), the unit for FOV is degrees (°), and FNO, Vd_B1, and Vd_B2 have no units.

[0184] Table 11

[0185]

[0186]

[0187] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the concept of this application. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. 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: A first lens with negative optical power; A second lens with negative optical power has a concave object side and a convex image side. A third lens with positive optical power has a convex object-side surface and a convex image-side surface; The fourth lens with optical power has a concave object side and a convex image side. The fifth lens with negative optical power has a concave object side and a concave image side. A sixth lens with positive optical power; A seventh lens with optical power; An eighth lens with optical power; A ninth lens with optical power; A tenth lens with optical power; The fixed-focus lens has ten lenses with optical power. The fixed-focus lens satisfies the following condition: -2.43≤(f2+f3) / f≤-0.45, Where f2 is the effective focal length of the second lens, f3 is the effective focal length of the third lens, and f is the total effective focal length of the fixed-focus lens.

2. The fixed-focus lens according to claim 1, characterized in that, The fourth lens has positive optical power, the seventh lens has negative optical power, the eighth lens has positive optical power, the ninth lens has negative optical power, and the tenth lens has positive optical power; or The fourth lens has negative optical power, the seventh lens has positive optical power, the eighth lens has negative optical power, the ninth lens has positive optical power, and the tenth lens has negative optical power.

3. The fixed-focus lens according to claim 1, characterized in that, The object-side surface of the first lens is convex, and the image-side surface is concave. 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 convex, and the image-side surface is either convex or concave. The object side of the eighth lens is convex, and the image side is either convex or concave. The object side of the ninth lens is either convex or concave, and the image side is either convex or concave. The object side of the tenth lens is either convex or concave, while the image side is concave.

4. The fixed-focus lens according to claim 1, characterized in that, The fifth lens and the sixth lens are cemented together to form a first cemented lens group; The seventh lens and the eighth lens are cemented together to form a second cemented lens group; or The eighth lens and the ninth lens are cemented together to form a second cemented lens group.

5. The fixed-focus lens according to claim 1, characterized in that, The fixed-focus lens satisfies at least one of the following conditions: -2.49≤f1 / f≤-1.85, -6.68≤(f1+f2) / f≤-4.09, 1.52≤f34 / f≤3.42, -2.66≤f5 / f≤-1.62, 1.42≤f6 / f≤2.34, 2.86≤|f7 / f|≤7.45, 1.60≤|f8 / f|≤5.31, 1.47≤|f9 / f|≤3.55, 2.33≤|f10 / f|≤4.88, Wherein, f1 is the effective focal length of the first lens, f2 is the effective focal length of the second lens, f34 is the combined effective focal length of the third and fourth lenses, f5 is the effective focal length 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, f9 is the effective focal length of the ninth lens, f10 is the effective focal length of the tenth lens, and f is the total effective focal length of the fixed-focus lens.

6. The fixed-focus lens according to claim 4, characterized in that, The fixed-focus lens satisfies at least one of the following conditions: 3.89≤fB1 / f≤12.96, 2.22≤fB2 / f≤3.04, 1.50≤fB1 / fB2≤5.10, 0.39mm -1 ≤|Vd_B1| / fB1≤1.21mm -1 2.19mm -1 ≤|Vd_B2| / fB2≤3.14mm -1 , Wherein, fB1 is the effective focal length of the first cemented lens group, fB2 is the effective focal length of the second cemented lens group, f is the total effective focal length of the fixed-focus lens, Vd_B1 is the difference in Abbe number between the two lenses in the first cemented lens group, and Vd_B2 is the difference in Abbe number between the two lenses in the second cemented lens group.

7. The fixed-focus lens according to claim 1, characterized in that, The fixed-focus lens satisfies the following condition: -0.05≤(R22+R31) / (R22-R31)≤0.03, Wherein, R31 is the radius of curvature of the object side of the third lens, and R22 is the radius of curvature of the image side of the second lens.

8. The fixed-focus lens according to claim 1, characterized in that, The fixed-focus lens satisfies the following condition: 5.50≤TTL / f≤7.67 Where f is the total effective focal length of the fixed-focus lens, and TTL is the total optical length of the fixed-focus lens.

9. The fixed-focus lens according to claim 1, characterized in that, The fixed-focus lens satisfies at least one of the following conditions: -2.26≤f1 / f≤-2.05, -6.08≤(f1+f2) / f≤-4.55, -2.21≤(f2+f3) / f≤-0.50, 1.68≤f34 / f≤3.11, -2.42≤f5 / f≤-1.80, 1.58≤f6 / f≤2.13, 3.18≤|f7 / f|≤6.77, 1.78≤|f8 / f|≤4.83, 1.63≤|f9 / f|≤3.23, 2.59≤|f10 / f|≤4.43, 6.11≤TTL / f≤6.98, Wherein, f1 is the effective focal length of the first lens, f2 is the effective focal length of the second lens, f3 is the effective focal length of the third lens, f34 is the combined effective focal length of the third and fourth lenses, f5 is the effective focal length 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, f9 is the effective focal length of the ninth lens, f10 is the effective focal length of the tenth lens, f is the total effective focal length of the fixed-focus lens, and TTL is the total optical length of the fixed-focus lens.

10. The fixed-focus lens according to claim 4, characterized in that, The fixed-focus lens satisfies at least one of the following conditions: 4.32≤fB1 / f≤11.78, 2.47≤fB2 / f≤2.77, 1.67≤fB1 / fB2≤4.64 0.43mm -1 ≤|Vd_B1| / fB1≤1.10mm -1 ,2.43mm -1 ≤|Vd_B2| / fB2≤2.85mm -1 , Wherein, fB1 is the effective focal length of the first cemented lens group, fB2 is the effective focal length of the second cemented lens group, f is the total effective focal length of the fixed-focus lens, Vd_B1 is the difference in Abbe number between the two lenses in the first cemented lens group, and Vd_B2 is the difference in Abbe number between the two lenses in the second cemented lens group.

Images