An optical lens

Abstract

This utility model discloses an optical lens, comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged sequentially along the optical axis from the object side to the image side. The first lens has negative optical power, the second lens has positive optical power, the third lens has positive optical power, the fourth lens has positive optical power, the fifth lens has negative optical power, the sixth lens has positive optical power, and the seventh lens has negative optical power. The first, second, fourth, fifth, sixth, and seventh lenses are all spherical glass lenses, and the third lens is a glass aspherical lens. The optical lens provided by this utility model embodiment employs seven lenses, using a hybrid structure of spherical and aspherical glass lenses, and rationally distributing the optical power of each lens, achieving a long focal length, narrow field of view optical lens that balances high resolution, miniaturization, large aperture, and weak ghosting.

Description

Technical Field

[0001] This utility model relates to the field of optical technology, and in particular to an optical lens. Background Technology

[0002] With the continuous development of technology, the automotive industry has also ushered in the era of intelligence. Intelligent driving assistance systems, as a crucial component of automotive intelligence, play a vital role in improving driving safety, reducing accident rates, and enhancing user experience. In the current booming development of automotive driver assistance technologies, in-vehicle cameras hold a pivotal position. In-vehicle cameras come in various types, including interior, rear, front, side, and surround view cameras. Each type has unique functions and different application scenarios.

[0003] As a core component of Advanced Driver Assistance Systems (ADAS), the forward-facing camera not only bears the important responsibility of distance measurement, but also needs to accurately identify objects and clearly distinguish road markings. The realization of these functions depends on high-quality image acquisition and complex visual processing algorithms, which puts extremely high demands on the imaging performance of the optical lens.

[0004] However, currently available automotive optical lenses still have certain limitations in terms of resolution, aperture size, temperature adaptability, ghosting suppression, and system size, making it difficult to fully meet the comprehensive requirements of forward-looking ADAS cameras for high definition, large light intake, compact structure, and high environmental adaptability. Utility Model Content

[0005] This invention provides an optical lens to solve the technical challenges of existing lenses in simultaneously achieving high resolution, miniaturization, large aperture, and low ghosting.

[0006] This utility model provides an optical lens, including a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged sequentially along the optical axis from the object side to the image side;

[0007] The first lens has negative optical power;

[0008] The second lens has positive optical power;

[0009] The third lens has positive optical power;

[0010] The fourth lens has positive optical power;

[0011] The fifth lens has negative optical power;

[0012] The sixth lens has positive optical power;

[0013] The seventh lens has negative optical power;

[0014] The first lens, the second lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are all glass spherical lenses, and the third lens is a glass aspherical lens.

[0015] Optionally, the focal length of the first lens is f1, the focal length of the second lens is f2, the focal length of the third lens is f3, the focal length of the fourth lens is f4, the focal length of the fifth lens is f5, the focal length of the sixth lens is f6, the focal length of the seventh lens is f7, and the focal length of the optical lens is F.

[0016] -3 <f1 / F<0;

[0017] 0 < f2 / F < 5;

[0018] 0 < f3 / F < 2;

[0019] 0 <f4 / F<2;

[0020] -2 <f5 / F<0;

[0021] 0 < f6 / F < 2;

[0022] -1.5 <f7 / F<0。

[0023] Optionally, the object-side surface of the first lens is concave, and the image-side surface is convex.

[0024] The object-side surface of the second lens is convex, and the image-side surface is concave.

[0025] The object-side surface of the third lens is convex, and the image-side surface is also convex.

[0026] The object-side surface of the fourth lens is convex, and the image-side surface is also convex.

[0027] The object-side surface of the fifth lens is concave, and the image-side surface is also concave.

[0028] The object-side surface of the sixth lens is convex, and the image-side surface is also convex.

[0029] The object-side surface of the seventh lens is concave, while the image-side surface is planar.

[0030] Optionally, the fourth lens and the fifth lens form a cemented lens group.

[0031] Optionally, the optical lens may also include an aperture stop;

[0032] The aperture is located in the optical path between the second lens and the third lens.

[0033] Optionally, the total optical length of the optical lens is TTL, and the image height corresponding to the maximum field of view of the optical lens is H; 6 < TTL / H < 7.

[0034] Optionally, the focal length of the optical lens is F, and the total optical length of the optical lens is TTL; TTL / F < 2.5.

[0035] Optionally, the optical back focal length of the optical lens is BFL, and the total optical length of the optical lens is TTL; BFL / TTL > 0.2.

[0036] Optionally, the entrance pupil diameter of the optical lens is ENPD, and the total optical length of the optical lens is TTL; ENPD / TTL > 0.2.

[0037] Optionally, the focal length of the fourth lens is f4, and the focal length of the fifth lens is f5; 0.5 < |f4 / f5| < 1.5.

[0038] Optionally, the combined focal length of the fourth lens and the fifth lens is f45, and the focal length of the optical lens is F; 10≤|f45 / F|≤20.

[0039] Optionally, the focal length of the first lens is f1, and the focal length of the second lens is f2; 0 < |f1+f2| / |f1-f2| < 1.

[0040] Optionally, the central radius of curvature of the object side of the first lens is R1, and the central radius of curvature of the image side of the first lens is R2; 1 < (R1 + R2) / R2 < 2.

[0041] Optionally, the central radius of curvature of the object side of the first lens is R1, and the central radius of curvature of the image side of the first lens is R2; -3<(R1+R2) / (R1-R2)<-1.

[0042] Optionally, the center radius of curvature of the object side of the second lens is R3, the center radius of curvature of the image side of the second lens is R4, and the center thickness of the second lens is d2; 0.5≤R3 / (R4+d2)≤1.2.

[0043] Optionally, the central radius of curvature of the image-side surface of the second lens is R4, and the focal length of the optical lens is F; R4 / F < 1.5.

[0044] Optionally, the central radius of curvature of the object side of the sixth lens is R11, and the focal length of the optical lens is F; R11 / F > 1.6.

[0045] The optical lens provided in this embodiment employs seven lenses, utilizing a hybrid structure of spherical and aspherical glass lenses. By rationally allocating the optical power of each lens, the lens achieves miniaturization (total length controlled within 32mm) while simultaneously possessing a large aperture (e.g., F-number ≤1.65), high resolution (supporting 8-megapixel and above image sensors), high relative illumination, and excellent stray light suppression. Furthermore, the selection of glass material ensures refractive index stability under both high and low temperature environments, significantly improving the lens's imaging reliability over a wide temperature range (-40℃ to +95℃). This optical lens not only meets the stringent requirements of Advanced Driver Assistance Systems (ADAS) forward-facing cameras for narrow field of view, long focal length, and high-precision target recognition, but also offers significant advantages in terms of low ghosting and mass production feasibility, enabling an 8-megapixel-level long focal length narrow field-of-view optical lens suitable for autonomous driving forward-facing systems.

[0046] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this utility model, nor is it intended to limit the scope of this utility model. Other features of this utility model will become readily apparent from the following description. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 A schematic diagram of the structure of an optical lens provided in an embodiment of this utility model;

[0049] Figure 2 This is a schematic diagram of another optical lens provided in an embodiment of the present invention;

[0050] Figure 3 This is a schematic diagram of the structure of another optical lens provided in an embodiment of the present utility model;

[0051] Figure 4 The ray fan pattern of the optical lens provided in Embodiment 1 of this utility model;

[0052] Figure 5 An axial aberration curve of an optical lens provided in Embodiment 1 of this utility model;

[0053] Figure 6 Field curvature distortion diagram of the optical lens provided in Embodiment 1 of this utility model;

[0054] Figure 7 The light field pattern of the optical lens provided in Embodiment 2 of this utility model;

[0055] Figure 8 An axial aberration curve of an optical lens provided in Embodiment 2 of this utility model;

[0056] Figure 9 The field curvature distortion diagram of the optical lens provided in Embodiment 2 of this utility model;

[0057] Figure 10 The light field pattern of the optical lens provided in Embodiment 3 of this utility model;

[0058] Figure 11 An axial aberration curve of the optical lens provided in Embodiment 3 of this utility model;

[0059] Figure 12 The field curvature distortion diagram of the optical lens provided in Embodiment 3 of this utility model. Detailed Implementation

[0060] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0061] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the utility model described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0062] Figure 1 This is a schematic diagram of the structure of an optical lens provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of another optical lens provided in an embodiment of the present invention. Figure 3 A schematic diagram of the structure of another optical lens provided in this embodiment of the present invention is shown below. Figures 1-3As shown, the optical lens provided in this embodiment of the present invention includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, and a seventh lens L7 arranged sequentially along the optical axis from the object side to the image side.

[0063] The first lens L1 has negative optical power, the second lens L2 has positive optical power, the third lens L3 has positive optical power, the fourth lens L4 has positive optical power, the fifth lens L5 has negative optical power, the sixth lens L6 has positive optical power, and the seventh lens L7 has negative optical power.

[0064] The first lens L1, the second lens L2, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7 are all glass spherical lenses, while the third lens L3 is a glass aspherical lens.

[0065] Specifically, optical power is equal to the difference between the convergence of the image-side beam and the convergence of the object-side beam; it characterizes the ability of an optical system to deflect light. The larger the absolute value of the optical power, the stronger its ability to bend light; the smaller the absolute value, the weaker its ability to bend light. When the optical power is positive, the refraction of light is converging; when the optical power is negative, the refraction of light is diverging. Optical power can be used to characterize a single refractive surface of a lens (i.e., one surface of the lens), a single lens, or a system formed by multiple lenses (i.e., a lens group).

[0066] In the lens provided in this embodiment, each lens can be fixed to a lens barrel. Figures 1-3 (Not shown in the text) but not limited to this.

[0067] The first lens L1 has negative optical power, which can diverge the incident light, thereby effectively expanding the incident beam angle range of the optical lens and increasing the field of view of the lens.

[0068] The second lens L2 has positive optical power, which helps the light to transition smoothly and corrects astigmatism and field curvature, thereby improving the imaging quality of the optical lens.

[0069] The third lens L3 also uses positive optical power and can be configured in conjunction with the second lens L2 to help smooth light transition, further correct astigmatism and field curvature, compress system tolerances, and improve imaging quality and mass production stability.

[0070] The fourth lens, L4, possesses positive optical power. In environments with alternating high and low temperatures, the focal point of an optical lens shifts due to thermal expansion and contraction of the lens materials and changes in refractive index temperature; this is known as back focus shift. The amount of back focus shift produced by a single lens is roughly proportional to its optical power (the reciprocal of its focal length). As a key lens with positive optical power, the strength of the fourth lens, L4, affects the thermal stability of the entire system. By setting the fourth lens L4 to have positive optical power and limiting its optical power within a reasonable range, excessive thermal back focus shift caused by excessively strong optical power is avoided. This effectively suppresses back focus shift over a wide temperature range (e.g., -40℃ to +95℃), ensuring that the imaging plane remains within the depth-of-field tolerance of the image sensor. This guarantees excellent image sharpness and stability even in high and low temperature environments, significantly improving the reliability of the product in harsh environments such as automotive applications and action cameras.

[0071] The fifth lens L5 has negative optical power, which can moderately diverge the beam converged by the front group, effectively reducing the incident angle of light at the edge of the image plane, thus adapting to large target surface imaging sensors, and effectively improving system aberrations (such as field curvature and distortion), ultimately improving edge field illumination and overall imaging quality.

[0072] The sixth lens L6 has positive optical power and converges the light rays that have diverged from the front lens group (especially the fifth lens L5 with negative optical power), thereby smoothly guiding the beam to the image plane. It can effectively correct the residual aberrations of the front lens group and improve the image quality.

[0073] The seventh lens L7 has negative optical power. By constraining the ratio of the focal length f7 of the seventh lens L7 to the overall focal length of the optical lens within a specific range, the seventh lens L7 can form a residual spherical aberration with the opposite sign and appropriate magnitude to the spherical aberration accumulated by the first six lenses. This allows the seventh lens L7 to accurately cancel the residual spherical aberration generated by the first six lenses, thereby achieving optimized control of the overall spherical aberration of the optical lens and improving the sharpness and contrast of the image.

[0074] Furthermore, glass has a lower coefficient of thermal expansion than plastic. The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7 are all made of glass. This makes the shape of the above lenses more stable when facing changes in ambient temperature, thereby reducing the impact of high and low temperatures on the imaging quality of the optical lens and avoiding the optical lens from becoming out of focus in different environments, achieving the characteristic of no out-of-focus from -40℃ to +95℃.

[0075] Meanwhile, glass has a higher refractive index than plastic, which can effectively adjust the light through the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6 and the seventh lens L7, thereby enhancing image clarity.

[0076] In addition, spherical lenses have a mature manufacturing process and relatively low cost, making them suitable for critical locations requiring high stability. The first lens L1, the second lens L2, the fourth lens L4, the fifth lens L5, the sixth lens L6, and the seventh lens L7 all adopt a spherical design, which helps to reduce lens costs. At the same time, when combined with other aspherical lenses, they can further optimize the overall aberration correction effect.

[0077] Aspherical lenses can effectively correct advanced aberrations such as spherical aberration and coma, significantly improving image quality. Therefore, aspherical lenses can achieve complex optical functions with fewer lenses, thereby reducing the overall length and size of the lens.

[0078] In this embodiment of the invention, the third lens L3 is an aspherical lens, which can effectively correct aberrations such as spherical aberration, field curvature, distortion and higher-order astigmatism, and significantly improve the resolution and relative illumination across the entire field of view, thereby meeting the imaging requirements of high-pixel image sensors of 8 megapixels and above.

[0079] Meanwhile, the third lens L3 incorporates an aspherical design, which can effectively correct the deviation of the light incident angle in different fields of view through surface optimization, thereby reducing system sensitivity and improving production yield.

[0080] It should be noted that the glass lens is made of various types of glass known to those skilled in the art, and this utility model embodiment will not elaborate on or limit this type of glass.

[0081] The optical lens provided in this embodiment employs seven lenses, utilizing a hybrid structure of spherical and aspherical glass lenses. By rationally allocating the optical power of each lens, the lens achieves miniaturization (total length controlled within 32mm) while simultaneously possessing a large aperture (e.g., F-number ≤1.65), high resolution (supporting 8-megapixel and above image sensors), high relative illumination, and excellent stray light suppression. Furthermore, the selection of glass material ensures refractive index stability under both high and low temperature environments, significantly improving the lens's imaging reliability over a wide temperature range (-40℃ to +95℃). This optical lens not only meets the stringent requirements of Advanced Driver Assistance Systems (ADAS) forward-facing cameras for narrow field of view, long focal length, and high-precision target recognition, but also offers significant advantages in terms of low ghosting and mass production feasibility, enabling an 8-megapixel-level long focal length narrow field-of-view optical lens suitable for autonomous driving forward-facing systems.

[0082] As a feasible embodiment, the focal length of the first lens L1 is f1, the focal length of the second lens L2 is f2, the focal length of the third lens L3 is f3, the focal length of the fourth lens L4 is f4, the focal length of the fifth lens L5 is f5, the focal length of the sixth lens L6 is f6, the focal length of the seventh lens L7 is f7, and the focal length of the optical lens is F; -3<f1 / F<0; 0<f2 / F<5; 0<f3 / F<2; 0<f4 / F<2; -2<f5 / F<0; 0<f6 / F<2; -1.5<f7 / F<0.

[0083] Wherein, the first lens L1 satisfies -3<f1 / F<0, so that the first lens L1 has an appropriate negative optical power, which is beneficial to receiving light incident at a large angle and effectively expanding the field of view of the optical lens.

[0084] The second lens L2 satisfies 0<f2 / F<5, so that the second lens L2 has an appropriate positive optical power, which is beneficial to the smooth transition of light, facilitates the correction of astigmatism and field curvature, and improves the imaging quality of the optical lens.

[0085] The third lens L3 satisfies 0<f3 / F<2, so that the third lens L3 has an appropriate positive optical power, which can form a coordinated configuration with the second lens L2, contribute to the smooth transition of light, further correct astigmatism and field curvature, compress system tolerances, and improve imaging quality and mass production stability.

[0086] The fourth lens L4 satisfies 0<f4 / F<2, so as to control the focal length of the fourth lens L4, optimize the optical power distribution of the system, facilitate the realization of temperature characteristics, and ensure that the lens can still maintain good imaging quality under high and low temperature conditions. Specifically, since the thermal focal shift of a lens is proportional to its own optical power, the above focal length constraint adopted by the fourth lens L4 can effectively control the rear focal shift caused by the fourth lens L4 when the temperature changes, thereby ensuring that the lens can still maintain stable imaging quality in a wide temperature range from -40°C to +95°C.

[0087] The fifth lens L5 satisfies -2<f5 / F<0, so that the fifth lens L5 has an appropriate negative optical power, which is beneficial to further diverging light, reducing the incident angle of the chief ray of the marginal field of view on the imaging surface, so as to adapt to a large-size image sensor (i.e., a large target surface) and improve the imaging quality of the marginal area.

[0088] The sixth lens L6 satisfies 0<f6 / F<2, so that the sixth lens L6 has an appropriate positive optical power, which can re-converge the light diverged by the fifth lens L5, smoothly guide the light beam to the image surface, and effectively correct residual aberrations such as spherical aberration and astigmatism of the system, so as to improve the imaging quality.

[0089] The seventh lens L7 satisfies -1.5<f7 / F<0. By constraining the ratio of the optical power of the seventh lens L7 to the focal length of the optical lens within a reasonable range, it generates a residual spherical aberration that has the opposite sign to the spherical aberration accumulated by the front lenses and a controllable magnitude, so as to perform final fine-tuning and balancing on the overall spherical aberration of the system, effectively improving the imaging sharpness and contrast under a large aperture, and enhancing the imaging quality.

[0090] At the same time, by controlling the optical power of each lens in the entire optical lens to be distributed according to a certain proportion, while ensuring the functions of the aforementioned lenses and achieving the required optical performance indicators (such as miniaturization, large field of view, large aperture, etc.), the balance of the incident angle of the front and rear lenses can also be ensured to reduce the sensitivity of the lenses, which is beneficial to improving the stability of the optical lens, and is conducive to correcting the system aberrations and improving the imaging quality.

[0091] As a feasible implementation, as shown in Figures 1-3 , the object side of the first lens L1 is a concave surface, and the image side thereof is a convex surface; the object side of the second lens L2 is a convex surface, and the image side thereof is a concave surface; the object side of the third lens L3 is a convex surface, and the image side thereof is a convex surface; the object side of the fourth lens L4 is a convex surface, and the image side thereof is a convex surface; the object side of the fifth lens L5 is a concave surface, and the image side thereof is a concave surface; the object side of the sixth lens L6 is a convex surface, and the image side thereof is a convex surface; the object side of the seventh lens L7 is a concave surface, and the image side thereof is a flat surface.

[0092] The surface shape of the lens will affect the propagation direction of light, determine how the light bends when passing through the lens, and further affect the light throughput of the lens as well as the quality and characteristics of imaging.

[0093] In this embodiment, through reasonable matching of the surface shapes of the respective lenses, while meeting the optical power requirements of each lens and achieving the required optical performance indicators, it is beneficial to further reduce the total optical length of the entire optical lens, so as to realize a miniaturized lens design. Moreover, it can also make the path of light smoother when passing through the entire optical lens, reduce unnecessary reflection and absorption, which is beneficial to improving the light throughput and imaging quality.

[0094] Wherein, the image side of the seventh lens L7 is a flat surface, which can reduce the influence of eccentricity or tilt errors that may occur during manufacturing and assembly processes on the imaging quality, thereby effectively reducing the overall sensitivity of the optical lens. At the same time, since the flat surface shape is easier to process and inspect compared with a complex curved surface, the manufacturing process is simplified, the processing difficulty and error probability are reduced, and the production yield of the product is further improved.

[0095] As a feasible implementation, as shown in Figures 1-3 , the fourth lens L4 and the fifth lens L5 constitute a cemented lens group G1.

[0096] Wherein, as shown in Figures 1-3 As shown, the fourth lens L4 and the fifth lens L5 can be glued together to form a cemented lens group G1.

[0097] In this embodiment, cementing the fourth lens L4 and the fifth lens L5 together can effectively correct the chromatic aberration of the lens, reduce the lens's eccentricity sensitivity, balance the lens's aberrations, and improve the lens's imaging quality.

[0098] As a possible implementation method, such as Figures 1-3 As shown, the optical lens also includes an aperture stop STO, which is located in the optical path between the second lens L2 and the third lens L3.

[0099] An aperture stop STO is provided between the second lens L2 and the third lens L3 to limit the light beam. The aperture stop STO can be located near the image side of the second lens L2, which can reduce the generation of optical lens astigmatism and help to gather the light entering the optical system and reduce the rear port diameter of the optical lens.

[0100] As a feasible implementation method, the total optical length of the optical lens is TTL, and the image height corresponding to the maximum field of view of the optical lens is H; 6 < TTL / H < 7.

[0101] The total optical length (TTL) of the optical lens is defined as the distance along the optical axis from the object side of the first lens L1 to the imaging surface (i.e., the photosensitive surface of the image sensor).

[0102] Image height H is defined as the half-height of the image plane (i.e., the vertical distance from the optical axis to the maximum imaging point) corresponding to the maximum field of view of the optical lens.

[0103] In this embodiment, the total optical length TTL of the optical lens and the image height H corresponding to the maximum field of view of the optical lens satisfy 6 < TTL / H < 7. This allows for a large image area while better compressing the total length of the lens, enabling the lens design to be miniaturized and easily mounted on other imaging devices.

[0104] As a feasible implementation method, the focal length of the optical lens is F, and the total optical length of the optical lens is TTL; TTL / F < 2.5.

[0105] By satisfying the above conditions, the overall length of the optical lens can be significantly shortened, making the lens more compact and lightweight, thus achieving miniaturized optical lenses. This makes it easier to integrate them into space-constrained devices such as car cameras, action cameras, or smartphones.

[0106] As a feasible implementation method, the optical back focal length of the optical lens is BFL, and the total optical length of the optical lens is TTL; BFL / TTL > 0.2.

[0107] The optical back focal length (BFL) is defined as the distance on the optical axis from the image side surface of the seventh lens (L7) to the imaging surface.

[0108] In this embodiment, the optical lens satisfies BFL / TTL > 0.2. Under the premise of achieving lens miniaturization (i.e., shorter TTL), by ensuring that the proportion of BFL to TTL is greater than 20%, sufficient physical space is reserved for image sensor, infrared cut-off filter (IRCF), protective glass and packaging structure, etc. On the basis of achieving miniaturization, it is conducive to the reliable assembly and mass production process of optical module.

[0109] As a feasible implementation method, the entrance pupil diameter of the optical lens is ENPD, and the total optical length of the optical lens is TTL; ENPD / TTL > 0.2.

[0110] The entrance pupil diameter (ENPD) is defined as the diameter of the image formed by the aperture through the front optical element when viewed from object space.

[0111] In this embodiment, the optical lens satisfies ENPD / TTL > 0.1. The large entrance pupil diameter allows the optical lens to have a small F-number (FNO), such as achieving a large aperture characteristic of FNO ≤ 1.65, thereby significantly improving the amount of light entering the lens in low-light environments and enhancing the signal-to-noise ratio and sharpness of imaging in nighttime or low-light scenes.

[0112] As a feasible implementation, the focal length of the fourth lens L4 is f4, and the focal length of the fifth lens L5 is f5; 0.5 < |f4 / f5| < 1.5.

[0113] In particular, by cementing the fourth lens L4 with positive optical power and the fifth lens L5 with negative optical power, chromatic aberration can be eliminated.

[0114] The fourth lens L4 and the fifth lens L5 satisfy the above conditions, making their focal lengths close and opposite in sign. At this time, the fifth lens L5 can effectively balance the aberrations generated by the fourth lens L4, achieving mutual cancellation and realizing a comprehensive balance of aberrations, thus effectively improving the resolving power of the lens.

[0115] As a feasible implementation, the combined focal length of the fourth lens L4 and the fifth lens L5 is f45, and the focal length of the optical lens is F; 10≤|f45 / F|≤20.

[0116] The combined focal length f45 of the fourth lens L4 and the fifth lens L5 is determined by the optical power of the fourth lens L4 and the bonding interface characteristics of the fifth lens L5.

[0117] In this embodiment, the optical lens meets the above range, which can reasonably limit the optical power ratio of the cemented lens, so that the light smoothly transitions to the rear, reduces the height of the light incident to the rear, slows down the upward trend of the light, and helps to improve the illumination of the edge field of view.

[0118] As a feasible implementation, the focal length of the first lens L1 is f1, and the focal length of the second lens L2 is f2; 0 < |f1+f2| / |f1-f2| < 1.

[0119] The above-mentioned conditional formula can effectively control the difference in optical power between the first lens L1 and the second lens L2 by reasonably limiting the focal length ratio, thereby synergistically correcting aberrations and enabling the optical lens to obtain higher imaging resolution.

[0120] As a feasible implementation, the central radius of curvature of the object side of the first lens L1 is R1, and the central radius of curvature of the image side of the first lens L1 is R2; 1 < (R1 + R2) / R2 < 2.

[0121] The aforementioned conditional formula, by precisely controlling the ratio of the curvature radii of the object-side and image-side surfaces of the first lens L1, optimizes its surface curvature and effectively balances the deflection of light rays at the edge of the field of view. This expands the field of view while rationally controlling astigmatism and distortion, ensuring image quality at the edge of the field of view. Furthermore, this surface configuration effectively reduces the sensitivity of the first lens L1 to assembly tolerances, improving product yield and stability.

[0122] As a feasible implementation, the central radius of curvature of the object side of the first lens L1 is R1, and the central radius of curvature of the image side of the first lens L1 is R2; -3<(R1+R2) / (R1-R2)<-1.

[0123] Among them, the first lens L1, which is controlled by the above-mentioned conditional control, has an appropriate surface shape, which is conducive to increasing the divergence of light, realizing large target surface imaging of the lens, and improving the imaging quality of the optical lens.

[0124] As a feasible implementation, the central radius of curvature of the object side of the second lens L2 is R3, the central radius of curvature of the image side of the second lens L2 is R4, and the central thickness of the second lens L2 is d2; 0.5≤R3 / (R4+d2)≤1.2.

[0125] The aforementioned conditional expression, by relating the surface curvature of the second lens L2 to its central thickness, jointly constrains its structural shape, making it approximate a concentric circle. This special structural design enables the peripheral light rays to generate the required optical path difference with the central light rays, allowing the central light rays to diverge appropriately, thus better coordinating with the paths of the peripheral light rays and smoothly guiding them into the rear optical system. Furthermore, it helps to reduce the deflection angle of the forward light rays, decrease the lens front diameter, and reduce the lens size, which is beneficial for achieving overall lens miniaturization and low-cost manufacturing.

[0126] As a feasible implementation, the central radius of curvature of the image side of the second lens L2 is R4, and the focal length of the optical lens is F; R4 / F < 1.5.

[0127] Specifically, by precisely controlling the ratio of the radius of curvature of the second lens L2 surface to the lens focal length, the relative position of the pupil image of the ghost image reflected from the object side of the second lens L2 on the focal plane can be adjusted, making it significantly deviate from the principal image plane. In other words, by controlling the radius of curvature of the second lens L2, the pupil image of the ghost image can be moved away from the focal plane, effectively reducing the relative energy value of the ghost image on the imaging plane, thereby suppressing the visibility of the ghost image, meeting the requirements for weak ghost images, and improving image purity and image quality.

[0128] As a feasible implementation, the central radius of curvature of the object side of the sixth lens L6 is R11, and the focal length of the optical lens is F; R11 / F > 1.6.

[0129] Specifically, by precisely controlling the ratio of the radius of curvature of the sixth lens L6 surface to the lens focal length, the relative position of the pupil image of the ghost image reflected from the object side of the sixth lens L6 on the focal plane can be adjusted, making it significantly deviate from the principal image plane. In other words, by controlling the radius of curvature of the sixth lens L6, the pupil image of the ghost image can be moved away from the focal plane, effectively reducing the relative energy value of the ghost image on the imaging plane, thereby suppressing the visibility of the ghost image, meeting the requirements for weak ghost images, and improving image purity and image quality.

[0130] As a possible implementation method, such as Figures 1-3 As shown, the optical lens provided in this embodiment of the present invention also includes a flat glass CG. The flat glass CG is located on the image side of the seventh lens L7, which can protect the imaging chip, prevent dust and contamination, and thus ensure the imaging effect of the lens.

[0131] In some cases, flat glass CG can also be used to correct specific aberrations or filter out unwanted light, but this embodiment of the present invention does not specifically limit this.

[0132] Specific embodiments of the optical lens applicable to the above-described embodiments are further described below with reference to the accompanying drawings.

[0133] Example 1

[0134] Continue to refer to Figure 1 The telephoto lens provided in Embodiment 1 of this utility model includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, and a seventh lens L7 arranged sequentially along the optical axis from the object plane to the image plane.

[0135] The fourth lens L4 and the fifth lens L5 form a cemented lens group G1. The aperture stop STO is located in the optical path between the second lens L2 and the third lens L3, and the flat glass CG is located on the image side of the seventh lens L7.

[0136] Table 1 details the surface type, radius of curvature, thickness, refractive index, and Abbe number of each lens in the optical lens provided in Embodiment 1, according to a feasible implementation method. The optical lenses in Table 1 correspond to... Figure 1 The optical lens shown.

[0137] Table 1 Design values ​​of optical physical parameters of optical lenses

[0138]

[0139] The surface number is assigned according to the order of the lenses. For example, "1" represents the object side of the first lens, "2" represents the image side of the first lens, and so on. The radius of curvature represents the curvature of the lens surface in millimeters (mm). A positive value means that the surface bends towards the image plane, and a negative value means that the surface bends towards the object plane. "PL" means that the surface is flat and the radius of curvature is infinite. The thickness represents the central axial distance between the current surface and the next surface in millimeters (mm). The material (nd) represents the refractive index, which is the ability of the material between the current surface and the next surface to deflect light. A space indicates that the current position is air and the refractive index is 1. The material (vd) represents the Abbe number, which is the dispersion characteristic of the material between the current surface and the next surface. A space indicates that the current position is air.

[0140] In this embodiment, the third lens is an aspherical lens, with both its object side 6 and image side 7 being aspherical.

[0141] Its non-spherical surface shape equation It can satisfy:

[0142] ;

[0143] In the formula, For an aspherical surface along the optical axis at a height of When the position is such that the distance from the vertex of the aspherical surface is the sag; = 1 / R, where R represents the paraxial radius of curvature of the mirror; The conic coefficient; , , , , It represents the higher-order aspheric coefficient.

[0144] For example, Table 2 details the conicity of the aspherical lens surface in Embodiment 1 according to a feasible implementation. and coefficients of higher-order terms , , , , .

[0145] Table 2 Design values ​​of the aspherical conic coefficient for aspherical lenses in optical lenses

[0146]

[0147] The total optical length of the optical lens provided in this embodiment is 30.96426 mm.

[0148] Figure 4 This is a ray fan diagram of an optical lens provided in Embodiment 1 of this utility model. The ray fan diagram not only reflects monochromatic aberrations of different wavelengths but also represents the magnitude of transverse chromatic aberration. The diagram shows the ray fan diagram of the optical lens at infinity. In a single image, the horizontal axis represents the normalized beam aperture, and the vertical axis represents the transverse aberration. The vertical axis in a single image can also represent the maximum dispersion range of the beam on the ideal image plane. Ideally, each curve should completely coincide with the horizontal axis, at which point all rays in the field of view are focused at the same point on the image plane. Figure 4 It can be seen that the transverse aberration of each wavelength of the optical lens is well corrected. In addition, the curves of each color are not obviously dispersed, indicating that the optical lens also has good correction of chromatic aberration, which can meet the usage requirements of the optical lens.

[0149] Figure 5 This is an axial aberration curve diagram of the optical lens provided in Embodiment 1 of this utility model. The axial aberration curve of the lens can effectively represent the spherical aberration and other parameter states of the optical system under different wavelength conditions. In the diagram, the vertical direction represents the normalized aperture, 0 indicates it is on the optical axis, and the vertex represents the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focal point, in millimeters (mm). Figure 5 It can be seen that the axial aberrations of normalized apertures of different wavelengths are all within a reasonable range, which can achieve the effect of forming a clear image.

[0150] Figure 6This is a field curvature distortion diagram of the optical lens provided in Embodiment 1 of this utility model. In the coordinate system on the left side of the diagram, the horizontal axis represents the magnitude of the field curvature, in mm; the vertical axis represents the normalized image height, which has no unit. Here, T represents meridion, and S represents arc distortion. In the coordinate system on the right side of the diagram, the horizontal axis represents the magnitude of the distortion (F-Tan (Theta)), in %; the vertical axis represents the normalized image height, which has no unit. Figure 6 As can be seen, the field curvature of the optical lens provided in this embodiment is effectively controlled, and at the same time, the distortion is also well corrected.

[0151] Example 2

[0152] Continue to refer to Figure 2 The optical lens provided in Embodiment 2 of this utility model includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, and a seventh lens L7 arranged sequentially along the optical axis from the object plane to the image plane.

[0153] The fourth lens L4 and the fifth lens L5 form a cemented lens group G1. The aperture stop STO is located in the optical path between the second lens L2 and the third lens L3, and the flat glass CG is located on the image side of the seventh lens L7.

[0154] Table 3 details the surface type, radius of curvature, thickness, refractive index, and Abbe number of each lens in the optical lens provided in Embodiment 2, using a feasible implementation method. The optical lenses in Table 3 correspond to... Figure 2 The optical lens shown.

[0155] Table 3 Design values ​​of optical physical parameters of optical lenses

[0156]

[0157] The surface number is assigned according to the order of the lenses. For example, "1" represents the object side of the first lens, "2" represents the image side of the first lens, and so on. The radius of curvature represents the curvature of the lens surface in millimeters (mm). A positive value means that the surface bends towards the image plane, and a negative value means that the surface bends towards the object plane. "PL" means that the surface is flat and the radius of curvature is infinite. The thickness represents the central axial distance between the current surface and the next surface in millimeters (mm). The material (nd) represents the refractive index, which is the ability of the material between the current surface and the next surface to deflect light. A space indicates that the current position is air and the refractive index is 1. The material (vd) represents the Abbe number, which is the dispersion characteristic of the material between the current surface and the next surface. A space indicates that the current position is air.

[0158] In this embodiment, the third lens is an aspherical lens, with both its object side 6 and image side 7 being aspherical.

[0159] Its non-spherical surface shape equation It can satisfy:

[0160] ;

[0161] In the formula, For an aspherical surface along the optical axis at a height of When the position is such that the distance from the vertex of the aspherical surface is the sag; = 1 / R, where R represents the paraxial radius of curvature of the mirror; The conic coefficient; , , , , It represents the higher-order aspheric coefficient.

[0162] For example, Table 4 details the conicity of the aspherical lens surface in Embodiment 2 according to a feasible implementation. and coefficients of higher-order terms , , , , .

[0163] Table 4 Design values ​​of the aspherical conic coefficient for aspherical lenses in optical lenses

[0164]

[0165] The optical lens provided in this embodiment has a total optical length of 31.60057 mm.

[0166] Figure 7 This is a ray fan diagram of the optical lens provided in Embodiment 2 of this utility model. The ray fan diagram not only reflects monochromatic aberrations of different wavelengths but also represents the magnitude of transverse chromatic aberration. The diagram shows the ray fan diagram of the optical lens at infinity. In a single image, the horizontal axis represents the normalized beam aperture, and the vertical axis represents the transverse aberration. The vertical axis in a single image can also represent the maximum dispersion range of the beam on the ideal image plane. Ideally, each curve should completely coincide with the horizontal axis, at which point all rays in the field of view are focused at the same point on the image plane. Figure 7 It can be seen that the transverse aberration of each wavelength of the optical lens is well corrected. In addition, the curves of each color are not obviously dispersed, indicating that the optical lens also has good correction of chromatic aberration, which can meet the usage requirements of the optical lens.

[0167] Figure 8This is an axial aberration curve diagram of the optical lens provided in Embodiment 2 of this utility model. The axial aberration curve of the lens can effectively represent the spherical aberration and other parameter states of the optical system under different wavelength conditions. In the diagram, the vertical direction represents the normalized aperture, 0 indicates it is on the optical axis, and the vertex represents the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focal point, in millimeters (mm). Figure 8 It can be seen that the axial aberrations of normalized apertures of different wavelengths are all within a reasonable range, which can achieve the effect of forming a clear image.

[0168] Figure 9 This is a field curvature distortion diagram of the optical lens provided in Embodiment 2 of this utility model. In the coordinate system on the left side of the figure, the horizontal axis represents the magnitude of the field curvature, in mm; the vertical axis represents the normalized image height, which has no unit. T represents meridion, and S represents arc distortion. In the coordinate system on the right side of the figure, the horizontal axis represents the magnitude of the distortion (F-Tan (Theta)), in %; the vertical axis represents the normalized image height, which has no unit. Figure 9 As can be seen, the field curvature of the optical lens provided in this embodiment is effectively controlled, and at the same time, the distortion is also well corrected.

[0169] Example 3

[0170] Continue to refer to Figure 3 The optical lens provided in Embodiment 3 of this utility model includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, and a seventh lens L7 arranged sequentially along the optical axis from the object plane to the image plane.

[0171] The fourth lens L4 and the fifth lens L5 form a cemented lens group G1. The aperture stop STO is located in the optical path between the second lens L2 and the third lens L3, and the flat glass CG is located on the image side of the seventh lens L7.

[0172] Table 5 details the surface type, radius of curvature, thickness, refractive index, and Abbe number of each lens in the optical lens provided in Embodiment 3, according to a feasible implementation method. The optical lenses in Table 5 correspond to... Figure 3 The optical lens shown.

[0173] Table 5 Design values ​​of optical physical parameters of optical lenses

[0174]

[0175] The surface number is assigned according to the order of the lenses. For example, "1" represents the object side of the first lens, "2" represents the image side of the first lens, and so on. The radius of curvature represents the curvature of the lens surface in millimeters (mm). A positive value means that the surface bends towards the image plane, and a negative value means that the surface bends towards the object plane. "PL" means that the surface is flat and the radius of curvature is infinite. The thickness represents the central axial distance between the current surface and the next surface in millimeters (mm). The material (nd) represents the refractive index, which is the ability of the material between the current surface and the next surface to deflect light. A space indicates that the current position is air and the refractive index is 1. The material (vd) represents the Abbe number, which is the dispersion characteristic of the material between the current surface and the next surface. A space indicates that the current position is air.

[0176] In this embodiment, the third lens is an aspherical lens, with both its object side 6 and image side 7 being aspherical.

[0177] Its non-spherical surface shape equation It can satisfy:

[0178] ;

[0179] In the formula, For an aspherical surface along the optical axis at a height of When the position is such that the distance from the vertex of the aspherical surface is the sag; = 1 / R, where R represents the paraxial radius of curvature of the mirror; The conic coefficient; , , , , It represents the higher-order aspheric coefficient.

[0180] For example, Table 6 details the conicity of the aspherical lens surface in Embodiment 3 according to a feasible implementation. and coefficients of higher-order terms , , , , .

[0181] Table 6 Design values ​​of the aspherical conic coefficient for aspherical lenses in optical lenses

[0182]

[0183] The total optical length of the optical lens provided in this embodiment three is 31.23384 mm.

[0184] Figure 10This is a ray fan plot of the optical lens provided in Embodiment 3 of this utility model. The ray fan plot not only reflects monochromatic aberrations of different wavelengths but also represents the magnitude of transverse chromatic aberration. The figure shows the ray fan plot of the optical lens at infinity. In a single plot, the horizontal axis represents the normalized beam aperture, and the vertical axis represents the transverse aberration. The vertical axis in a single image can also represent the maximum dispersion range of the beam on the ideal image plane. Ideally, each curve should completely coincide with the horizontal axis, at which point all rays in the field of view are focused at the same point on the image plane. Figure 10 It can be seen that the transverse aberration of each wavelength of the optical lens is well corrected. In addition, the curves of each color are not obviously dispersed, indicating that the optical lens also has good correction of chromatic aberration, which can meet the usage requirements of the optical lens.

[0185] Figure 11 This is an axial aberration curve diagram of the optical lens provided in Embodiment 3 of this utility model. The axial aberration curve of the lens can effectively represent the spherical aberration and other parameter states of the optical system under different wavelength conditions. In the diagram, the vertical direction represents the normalized aperture, 0 indicates it is on the optical axis, and the vertex represents the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focal point, in millimeters (mm). Figure 11 It can be seen that the axial aberrations of normalized apertures of different wavelengths are all within a reasonable range, which can achieve the effect of forming a clear image.

[0186] Figure 12 This is a field curvature distortion diagram of the optical lens provided in Embodiment 3 of this utility model. In the coordinate system on the left side of the figure, the horizontal axis represents the magnitude of the field curvature, in mm; the vertical axis represents the normalized image height, which has no unit. T represents meridion, and S represents arc distortion. In the coordinate system on the right side of the figure, the horizontal axis represents the magnitude of the distortion (F-Tan (Theta)), in %; the vertical axis represents the normalized image height, which has no unit. Figure 12 As can be seen, the field curvature of the optical lens provided in this embodiment is effectively controlled, and at the same time, the distortion is also well corrected.

[0187] To provide a clearer explanation of the above embodiments, Table 7 details the specific optical physical parameters of each lens in the optical lenses provided in embodiments one to three of this utility model.

[0188] Table 7 Design values ​​of optical physical parameters of optical lenses

[0189]

[0190] The specific embodiments described above do not constitute a limitation on the scope of protection of this utility model. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. An optical lens, characterized in that, It includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged sequentially along the optical axis from the object side to the image side; The first lens has negative optical power; The second lens has positive optical power; The third lens has positive optical power; The fourth lens has positive optical power; The fifth lens has negative optical power; The sixth lens has positive optical power; The seventh lens has negative optical power; The first lens, the second lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are all glass spherical lenses, and the third lens is a glass aspherical lens.

2. The optical lens according to claim 1, characterized in that, The focal length of the first lens is f1, the focal length of the second lens is f2, the focal length of the third lens is f3, the focal length of the fourth lens is f4, the focal length of the fifth lens is f5, the focal length of the sixth lens is f6, the focal length of the seventh lens is f7, and the focal length of the optical lens is F; -3 <f1 / F<0;0<f2 / F<5;0<f3 / F<2;0<f4 / F<2;-2<f5 / F<0;0<f6 / F<2;-1.5<f7 / F<0。 3. The optical lens according to claim 1, characterized in that, The object-side surface of the first lens is concave, and the image-side surface is convex. The object-side surface of the second lens is convex, and the image-side surface is concave. The object-side surface of the third lens is convex, and the image-side surface is also convex. The object-side surface of the fourth lens is convex, and the image-side surface is also convex. The object-side surface of the fifth lens is concave, and the image-side surface is also 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 concave, while the image-side surface is planar.

4. The optical lens according to claim 1, characterized in that, The fourth lens and the fifth lens form a cemented lens group.

5. The optical lens according to claim 1, characterized in that, The optical lens also includes an aperture stop; The aperture stop is located in the optical path between the second lens and the third lens.

6. The optical lens according to claim 1, characterized in that, The total optical length of the optical lens is TTL, and the image height corresponding to the maximum field of view of the optical lens is H; 6 < TTL / H < 7.

7. The optical lens according to claim 1, characterized in that, The focal length of the optical lens is F, and the total optical length of the optical lens is TTL; TTL / F < 2.

5.

8. The optical lens according to claim 1, characterized in that, The optical back focal length of the optical lens is BFL, and the total optical length of the optical lens is TTL; BFL / TTL > 0.

2.

9. The optical lens according to claim 1, characterized in that, The entrance pupil diameter of the optical lens is ENPD, and the total optical length of the optical lens is TTL; ENPD / TTL > 0.

2.

10. The optical lens according to claim 1, characterized in that, The focal length of the fourth lens is f4, and the focal length of the fifth lens is f5; 0.5 < |f4 / f5| < 1.

5.

11. The optical lens according to claim 1, characterized in that, The combined focal length of the fourth lens and the fifth lens is f45, and the focal length of the optical lens is F; 10≤|f45 / F|≤20.

12. The optical lens according to claim 1, characterized in that, The focal length of the first lens is f1, and the focal length of the second lens is f2; 0 < |f1+f2| / |f1-f2| < 1.

13. The optical lens according to claim 1, characterized in that, The central radius of curvature of the object side of the first lens is R1, and the central radius of curvature of the image side of the first lens is R2; 1 < (R1 + R2) / R2 < 2.

14. The optical lens according to claim 1, characterized in that, The central radius of curvature of the object side of the first lens is R1, and the central radius of curvature of the image side of the first lens is R2; -3<(R1+R2) / (R1-R2)<-1.

15. The optical lens according to claim 1, characterized in that, The central radius of curvature of the object side of the second lens is R3, the central radius of curvature of the image side of the second lens is R4, and the central thickness of the second lens is d2; 0.5≤R3 / (R4+d2)≤1.

2.

16. The optical lens according to claim 1, characterized in that, The central radius of curvature of the image-side surface of the second lens is R4, and the focal length of the optical lens is F; R4 / F < 1.

5.

17. The optical lens according to claim 1, characterized in that, The central radius of curvature of the object side of the sixth lens is R11, and the focal length of the optical lens is F; R11 / F > 1.6.

Images