An optical lens

Abstract

The application discloses an optical lens, comprising first to seventh lenses arranged in sequence along an optical axis from an object side to an image side; the first lens has positive focal power and is a convex-concave type; the second lens has negative focal power and is a concave-concave type; the third lens has positive focal power and is a convex-convex type; the fourth lens has positive focal power and is a convex-convex type; the fifth lens has negative focal power and is a concave-concave type; the sixth lens has positive focal power and an object side surface thereof is a convex surface; the seventh lens has negative focal power and is a concave-convex type; further comprising a filter, the filter being arranged between the second lens and the third lens; or, the filter being arranged between the third lens and the fourth lens; the fourth lens and the fifth lens forming a cemented lens. The optical lens has high definition, low ghosting and high-quality imaging capability, and meets the demand of a modern automobile front vision system.

Description

Technical Field

[0001] The present invention relates to the field of optical imaging technology, and in particular to an optical lens. Background Technology

[0002] As people's demands for driving experience continue to increase, automotive optical lenses are being used more and more in driver assistance systems, and the status of automotive optical lenses in the automotive industry is constantly rising.

[0003] Advanced Driver Assistance Systems (ADAS) play a crucial role in intelligent driving. They use various lenses and sensors to collect environmental information to ensure driver safety. Existing ADAS lenses not only require a slim and compact design with high pixel count and high resolution, but also must be able to produce clear images in low-light conditions. Therefore, the market urgently needs a miniaturized optical system with a large aperture, high relative illumination, and high pixel count and high resolution to meet the demands of modern automotive forward-looking systems.

[0004] Existing automotive optical lenses often struggle to balance miniaturization and large aperture characteristics when achieving high-pixel imaging, or they suffer from poor image quality in low-light conditions. Furthermore, traditional lenses are prone to producing strong ghosting between the filter and the sensor, affecting image quality. Summary of the Invention

[0005] This invention provides an optical lens with high-definition, low-ghosting imaging capabilities, meeting the needs of modern automotive forward-looking systems.

[0006] In a first aspect, this application provides 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;

[0007] The first lens has positive optical power, and its object side is convex and its image side is concave.

[0008] The second lens has negative optical power, and its object side is concave, as is its image side;

[0009] The third lens has positive optical power, and its object side is convex, as is its image side;

[0010] The fourth lens has positive optical power, and its object side is convex, as is its image side;

[0011] The fifth lens has negative optical power, and its object side is concave, as is its image side;

[0012] The sixth lens has positive optical power and its object-side surface is convex.

[0013] The seventh lens has negative optical power, and its object side is concave while its image side is convex.

[0014] It also includes a filter disposed between the second lens and the third lens; or, the filter is disposed between the third lens and the fourth lens; the fourth lens and the fifth lens form a cemented lens.

[0015] Optionally, the distance dIR between the filter IR and the image plane and the total optical length TTL of the optical lens satisfy the following condition: 0.5 <dIR / TTL<0.82。

[0016] Optionally, the optical power of the first to seventh lenses satisfies the following condition:

[0017] 0.45≤Φ1 / Φ≤0.61; -1.36≤Φ2 / Φ≤-1.10; 0.96≤Φ3 / Φ≤1.19;

[0018] 0.95≤Φ4 / Φ≤1.38; -1.67≤Φ5 / Φ≤-1.09; 0.92≤Φ6 / Φ≤1.20; -1.19≤Φ7 / Φ≤-0.68;

[0019] Wherein, Φ is the total optical power of the optical lens, and Φ1, Φ2, Φ3, Φ4, Φ5, Φ6, and Φ7 represent the optical powers of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens, respectively, in sequence.

[0020] Optionally, the refractive index and Abbe number of the first lens to the seventh lens satisfy the following condition:

[0021] 1.68≤n1≤1.93; 34.8≤v1≤56.0; 1.51≤n2≤1.60; 40.2≤v2≤56.5;

[0022] 1.57≤n3≤1.64; 62.9≤v3≤68.8; 1.48≤n4≤1.64; 62.9≤v4≤71.8;

[0023] 1.63≤n5≤1.72; 29.6≤v5≤34.4; 1.78≤n6≤1.97; 31.8≤v6≤47.1;

[0024] 1.67≤n7≤1.94; 20.4≤v7≤41.5;

[0025] Wherein, n1, n2, n3, n4, n5, n6, and n7 represent the refractive indices of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens, respectively, and v1, v2, v3, v4, v5, v6, and v7 represent the Abbe numbers of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens, respectively, in sequence.

[0026] Optionally, an aperture stop is provided between the second lens and the third lens to limit the light beam.

[0027] Optionally, the system focal length F of the optical lens and the total optical length TTL of the optical lens satisfy the following condition: TTL / F < 2.4.

[0028] Optionally, the maximum aperture D on the image side of the optical lens, the maximum field of view (FOV) of the optical lens, and the image height H corresponding to the maximum field of view (FOV) of the optical lens satisfy the following relationship: D / H / FOV < 0.05.

[0029] Optionally, the optical back focal length (BFL) of the optical lens and the total optical length (TTL) of the optical lens satisfy the following condition: BFL / TTL > 0.08.

[0030] Optionally, the entrance pupil diameter ENPD of the optical lens and the total optical length TTL of the optical lens satisfy the following condition: ENPD / TTL > 0.28.

[0031] Optionally, the central radius of curvature R1 of the object side of the first lens and the central radius of curvature R2 of the image side of the first lens satisfy the following condition: R1 / R2 < 0.55.

[0032] In summary, the optical lens provided by this invention achieves a large aperture (small FNO) and high resolution (8MP level) using only seven spherical glass lenses through an alternating arrangement of positive-negative-positive-positive-negative-positive-negative optical power and a specific surface combination. Furthermore, by placing the filter in the middle of the lens (between the second and third lenses or between the third and fourth lenses), the distance between the filter and the sensor is effectively increased, significantly reducing the ghosting energy caused by reflection between the filter and the sensor. At the same time, the fourth and fifth lenses are cemented together to effectively correct chromatic aberration, giving the system high-definition, low-ghosting imaging capabilities, meeting the needs of modern automotive front-view systems. Attached Figure Description

[0033] Figure 1 This application provides a detailed structural diagram of an optical lens according to Embodiment 1.

[0034] Figure 2This application provides a ray fan pattern for an optical lens according to Embodiment 1;

[0035] Figure 3 An axial aberration curve of an optical lens provided in this embodiment;

[0036] Figure 4 For the field curvature distortion diagram of an optical lens provided in this embodiment 1;

[0037] Figure 5 This application provides a detailed structural diagram of an optical lens according to Embodiment 2.

[0038] Figure 6 This application provides a ray fan pattern for an optical lens according to Embodiment 2.

[0039] Figure 7 An axial aberration curve of an optical lens provided in this second embodiment;

[0040] Figure 8 For the field curvature distortion diagram of an optical lens provided in this second embodiment;

[0041] Figure 9 This application provides a detailed structural diagram of an optical lens according to Embodiment 3.

[0042] Figure 10 This application provides a ray fan pattern for an optical lens according to Embodiment 3;

[0043] Figure 11 An axial aberration curve of an optical lens provided in this embodiment three is shown in the application.

[0044] Figure 12 For the field curvature distortion diagram of an optical lens provided in this embodiment three;

[0045] Figure 13 This application provides a detailed structural diagram of an optical lens according to Embodiment 4.

[0046] Figure 14 This application provides a ray fan pattern for an optical lens according to Embodiment 4;

[0047] Figure 15 An axial aberration curve of an optical lens provided in this embodiment four is shown in the application.

[0048] Figure 16 This is a field curvature distortion diagram of an optical lens provided in Embodiment 4 of this application. Detailed Implementation

[0049] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the invention and not all structures. Various modifications and variations can be made to the present invention without departing from its core concept or scope, which will be apparent to those skilled in the art. Therefore, the present invention is intended to cover modifications and variations falling within the scope of the corresponding claims (the claimed technical solutions) and their equivalents. It should be noted that the embodiments provided in the present invention can be combined with each other without contradiction.

[0050] The present invention provides an optical lens in view of one or more of the above-mentioned problems existing in the prior art. Figure 1 This is a schematic diagram of the lens structure of an optical lens provided in Embodiment 1 of this application, with reference to... Figure 1 This application provides an optical lens comprising 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. The first lens L1 has positive optical power, with a convex object side and a concave image side; the second lens L2 has negative optical power, with a concave object side and a concave image side; the third lens L3 has positive optical power, with a convex object side and a convex image side; the fourth lens L4 has positive optical power, with a convex object side and a convex image side; the fifth lens L5 has negative optical power, with a concave object side and a concave image side; the sixth lens L6 has positive optical power, with a convex object side; and the seventh lens L7 has negative optical power, with a concave object side and a convex image side.

[0051] The optical lens also includes a filter IR, which is positioned between the second lens L2 and the third lens L3; or, the filter IR is positioned between the third lens L3 and the fourth lens L4. The fourth lens L4 and the fifth lens L5 form a cemented lens, which can effectively correct chromatic aberration of the optical lens, reduce the off-center sensitivity of the optical lens, balance the aberrations of the optical lens, and improve the imaging quality of the optical lens.

[0052] The surface of the lens closer to the object side is called the object-side surface, and the surface of the lens closer to the image side is called the image-side surface.

[0053] Optical power is equal to the difference between the convergence of the image-side beam and the convergence of the object-side beam, and its value is the reciprocal of the focal length. It characterizes the ability of an optical lens to deflect light. The larger the absolute value of optical power, the stronger the bending ability of light; the smaller the absolute value of optical power, the weaker the bending ability of 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 lens group formed by multiple lenses.

[0054] Specifically, refer to Figure 1 The first lens L1, as the front light-receiving element of the optical system, has a convex object-side surface that can efficiently converge a wide beam of light incident from the object side at a large angle, providing the main force for the deflection of the main ray; its concave image-side surface can be used to smoothly transition the beam angle, avoiding excessive deflection angle when the light is incident on subsequent lenses, thus preventing the generation of higher-order spherical aberrations. The first lens L1 also adopts positive optical power, which is beneficial for compressing the beam aperture and realizing the miniaturization of the lens head.

[0055] The second lens L2 has a negative optical power and a biconcave shape, which can diverge the light rays initially converged by the first lens L1. Together with the first lens L1, it forms a "positive-negative" anti-telephoto structure. On the one hand, it can effectively expand the field of view of the optical system to meet the requirements of forward wide-angle. On the other hand, the diverging light rays generated by the negative optical power cancel each other out with the positive spherical aberration of the first lens L1, compensating for spherical aberration and coma, thereby providing a suitable incident height for subsequent lenses.

[0056] The third lens L3, with positive optical power and a biconvex shape, is one of the core converging elements of the system. It can refocus the light rays diverged by the second lens L2, accounting for a large positive share of the total optical power. The third lens L3, in conjunction with the second lens L2, can effectively balance the astigmatism and field curvature introduced by the negative lens. At the same time, it can also use high Abbe number materials to significantly reduce axial chromatic aberration and ensure high resolution in the central field of view.

[0057] The fourth lens, L4, also employs positive optical power and a biconvex shape, enabling precise beam focusing. The fact that both the fourth and third lenses, L3, use positive optical power prevents excessive concentration of optical power in a single lens, thus avoiding increased aberrations. This lens is cemented with the fifth lens, L5. The convex image-side surface of this lens allows adjustment of the angle of the beam incident on the cemented surface before cementing, thereby optimizing the dispersion compensation effect at the cemented interface.

[0058] The fifth lens, L5, is a negative power, biconcave type, and together with the fourth lens, L4, forms a cemented lens group. The cemented structure allows the eccentricity tolerances of the two lenses to cancel each other out, reducing assembly sensitivity and ensuring the stability of mass production.

[0059] The sixth lens L6 has positive optical power, and its convex object side surface can converge and compress the light beam passing through the cemented group. This lens with positive optical power can shorten the total track length (TTL) of the optical system, rapidly converge the light to the image plane IMA while keeping the focal length unchanged, which facilitates the miniaturization design of the optical lens.

[0060] The seventh lens L7 has negative optical power and a meniscus shape with a convex-concave surface profile, which can serve as the last aberration correction lens of the system. The negative optical power can slightly diverge and lift the light rays of the marginal field of view, so as to correct the residual field curvature (Petzval surface) and distortion (TV distortion). Its concave object side surface design is beneficial to smoothly deflect the marginal light rays to the image plane IMA, thereby ensuring the imaging clarity and low distortion in the full field of view (including the edge).

[0061] It should be emphasized that in the present application, the IR filter is arranged between the second lens L2 and the third lens L3; alternatively, the IR filter is arranged between the third lens L3 and the fourth lens L4, which helps to increase the distance between the IR filter and the sensor, reduces the energy value of ghost images generated between the IR filter and the sensor, and improves the high-quality imaging picture of the optical imaging system.

[0062] In summary, through the alternating arrangement of positive-negative-positive-positive-negative-positive-negative optical power and the specific surface profile combination, all of the first lens L1 to the seventh lens L7 in the present application can adopt spherical glass lenses. Under the condition of using only 7 spherical glass lenses, the resolution of large aperture (small FNO) and high pixel (8MP level) is achieved. By arranging the filter in the middle of the lenses (between the second and third lenses or between the third and fourth lenses), the distance between the filter and the photosensitive chip is effectively increased, the energy of ghost images caused by reflection between the filter and the sensor is significantly reduced. Meanwhile, the cemented combination of the fourth and fifth lenses is used to effectively correct chromatic aberration, so that the system has high-definition, low-ghost high-quality imaging capability, and meets the requirements of modern automotive forward-looking systems.

[0063] On the basis of the above embodiments, reference is made to Figure 1 , the distance dIR between the IR filter and the image plane IMA and the total optical track length TTL of the optical system satisfy: 0.5<dIR / TTL<0.82. Specifically, in the present application, the position of the IR filter is constrained within this numerical range, which can not only ensure that the IR filter is located in a region where the light converges relatively gently in the optical path, avoiding the wavelength shift of the filter caused by an excessively large incident angle, but also ensure that the IR filter is far enough away from the sensor. The multiple reflection light spots at this distance will be greatly defocused or diffused on the image plane IMA, so that the ghost image energy value is reduced to an invisible level, without excessively increasing the back focal length of the lens. This numerical constraint range takes into account both optical performance and assembly feasibility.

[0064] Based on the above embodiments, refer to Figure 1 The optical power of the first lens L1 to the seventh lens L7 satisfies the following condition:

[0065] 0.45≤Φ1 / Φ≤0.61; -1.36≤Φ2 / Φ≤-1.10; 0.96≤Φ3 / Φ≤1.19;

[0066] 0.95≤Φ4 / Φ≤1.38; -1.67≤Φ5 / Φ≤-1.09; 0.92≤Φ6 / Φ≤1.20; -1.19≤Φ7 / Φ≤-0.68;

[0067] Wherein, Φ is the total optical power of the optical lens, and Φ1, Φ2, Φ3, Φ4, Φ5, Φ6, and Φ7 represent the optical powers of 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, respectively.

[0068] Specifically, this application achieves a reasonable allocation of the optical power burden on the system by strictly limiting the ratio of the optical power of each lens to the total optical power. This avoids spherical aberration problems caused by excessive concentration of positive optical power, and also avoids the problem of excessively large field of view and distortion that is difficult to correct due to excessive negative optical power. Within this range, the optical system provided by the embodiments of this application can naturally balance spherical aberration, coma, and field curvature, while effectively compressing the total optical length, which helps to achieve a balance between system miniaturization and high image quality.

[0069] Refractive index is the ratio of the speed of light in a vacuum to the speed of light in a medium. It is mainly used to describe a material's ability to refract light. Different materials have different refractive indices; the higher the refractive index, the slower the light travels in that material. The Abbe number is an index used to represent the dispersion ability of a transparent medium; it can also be called the dispersion coefficient. The more severe the dispersion of the medium, the smaller the Abbe number; conversely, the less severe the dispersion, the larger the Abbe number. Generally speaking, refractive index and Abbe number are inversely proportional. This means that materials with higher refractive indices tend to have lower Abbe numbers, and vice versa.

[0070] Based on the above embodiments, refer to Figure 1 The refractive indices and Abbe numbers of the first lens L1 to the seventh lens L7 satisfy the following conditions:

[0071] 1.68≤n1≤1.93; 34.8≤v1≤56.0; 1.51≤n2≤1.60; 40.2≤v2≤56.5;

[0072] 1.57≤n3≤1.64; 62.9≤v3≤68.8; 1.48≤n4≤1.64; 62.9≤v4≤71.8;

[0073] 1.63≤n5≤1.72; 29.6≤v5≤34.4; 1.78≤n6≤1.97; 31.8≤v6≤47.1;

[0074] 1.67≤n7≤1.94; 20.4≤v7≤41.5;

[0075] Wherein, n1, n2, n3, n4, n5, n6, and n7 represent the refractive indices of 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, respectively, and v1, v2, v3, v4, v5, v6, and v7 represent the Abbe numbers of 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, respectively.

[0076] Specifically, this application achieves excellent achromatic effect by matching the refractive index (nd) and Abbe number (vd) of the seven lenses with high and low values ​​(e.g., high nd with low vd, and low nd with high vd). In particular, the third lens L3 and the fourth lens L4 use extremely high Abbe numbers (>62), while the fifth, sixth, and seventh lenses use medium and low Abbe numbers. This material combination helps to control the axial and transverse chromatic aberrations across the entire visible light spectrum within a very small range (axial aberration within ±0.05mm), ensuring the color reproduction and sharpness of the system in low-light color imaging.

[0077] It should be noted that in this application, the fourth lens L4 and the fifth lens L5 are cemented together. At the cementing interface, the strong difference in refractive index and dispersion between the materials of the fourth lens L4 and the fifth lens L5 (high Abbe number / low Abbe number) is used to introduce reverse dispersion in the converging beam, thereby significantly correcting the transverse chromatic aberration (magnification chromatic aberration) and the second-order spectrum.

[0078] Based on the above embodiments, refer to Figure 1 An aperture stop STO is provided between the second lens L2 and the third lens L3 to limit the light beam. This application positions the aperture stop STO between the second lens L2 and the third lens L3, preferably near the object side of the second lens L2, rather than at the very front of the optical lens. This effectively reduces the incident angle of the principal ray in the off-axis field of view on the lens surface, thereby significantly reducing astigmatism and distortion of the system. Simultaneously, this position improves the optical power symmetry between the front group (first lens L1 and second lens L2) and the rear group (third lens L3 to seventh lens L7), which helps to concentrate the light entering the optical system, reducing the rear aperture of the optical lens and thus lowering the overall size and cost of the lens.

[0079] Based on the above embodiments, refer to Figure 1The system focal length F of the optical lens and the total optical length TTL of the optical lens must satisfy the condition: TTL / F < 2.4. This application constrains the ratio of the total optical length TTL to the system focal length F to be less than 2.4, directly limiting the axial dimension of the lens. Complex aberration corrections are then performed within this compact space, ensuring that the lens can adapt to the limited installation space of modern automobiles (such as the inside of the windshield) and meet the stringent requirements of ADAS systems for thin and compact lenses.

[0080] Based on the above embodiments, refer to Figure 1 The maximum aperture D on the image side of the optical lens, the maximum field of view (FOV) of the optical lens, and the image height H corresponding to the maximum field of view (FOV) of the optical lens satisfy the condition: D / H / FOV < 0.05. By constraining the relationship between the maximum aperture D, the image height corresponding to the maximum field of view (FOV), and the field of view, the radial dimension of the first lens L1 of the lens is effectively controlled. When this condition is met, the volume of each lens glass in the optical lens is small, which not only reduces the material cost of the lens but also reduces the overall aperture size, which is beneficial for vehicle exterior design and aerodynamic drag optimization.

[0081] Based on the above embodiments, refer to Figure 1 The optical back focal length (BFL) and total optical length (TTL) of the optical lens satisfy the condition: BFL / TTL > 0.08. This application, through this constraint, achieves a shorter total optical length for the optical system, enabling miniaturization, while maintaining a long back focal length (BFL) sufficient to accommodate the protective glass and module assembly tolerances. This constraint provides ample operational space for optical lens alignment, reduces assembly difficulty, and improves production yield.

[0082] Based on the above embodiments, refer to Figure 1 The entrance pupil diameter (ENPD) and total optical length (TTL) of the optical lens must satisfy the condition: ENPD / TTL > 0.28. This application, by constraining the ratio of entrance pupil diameter (ENPD) to total optical length (TTL) to be greater than 0.28, essentially ensures that the system possesses large aperture characteristics (i.e., sufficiently small FNO). When this condition is met, the system can still capture sufficient light energy in low-light automotive environments such as dawn, dusk, or tunnels, guaranteeing image signal-to-noise ratio and clarity, thus ensuring reliable operation of the ADAS system in all-weather scenarios.

[0083] FNO, short for F-Number (aperture number), is usually written as F / # or F-value. It is the reciprocal of the relative aperture.

[0084] Mathematical definition (calculation formula): FNO = f / D. Where f is the system focal length of the optical lens, and D is the entrance pupil diameter, i.e., the effective light-transmitting aperture.

[0085] Based on the above embodiments, refer to Figure 1 The central radius of curvature R1 of the object-side surface of the first lens L1 and the central radius of curvature R2 of the image-side surface of the first lens L1 satisfy the condition: R1 / R2 < 0.55. By constraining the ratio of the central radii of curvature of the object-side and image-side surfaces of the first lens L1 to be less than 0.55, the first lens L1 is made to have a meniscus shape with a much larger curvature on the object side than on the image side. This strong asymmetry design allows the incident angle of edge field rays on the first lens L1 to tend to be consistent, significantly reducing the tolerance sensitivity of the optical system to temperature changes and assembly tilt, and enabling the lens to maintain stable and excellent performance within the automotive temperature range of -40℃ to 105℃ and during mass production.

[0086] Optional, refer to Figure 1 As shown, the optical lens may also include a flat glass CG, disposed in the optical path between the seventh lens L7 and the image plane IMA. The flat glass CG can protect the photosensitive chip in the imaging sensor. The photosensitive chip is used to convert the light signals collected by the optical lens into electrical signals, thereby ensuring the imaging effect of the optical lens.

[0087] In summary, the optical lens provided in this application, through the rational design of the seven-lens structure, the optimized allocation of the optical power of each lens, the careful matching of each lens material (refractive index and Abbe number), and the reasonable setting of the aperture stop and filter positions, achieves the technical effects of high pixel count (8 megapixel level), large aperture, high definition, miniaturization (total length within 32.7mm) and weak ghosting, which can meet the high requirements of forward-looking long focal length narrow-angle lenses for autonomous driving.

[0088] Specific embodiments of the optical lens applicable to the above-described embodiments are further described below with reference to the accompanying drawings.

[0089] Example 1

[0090] Continue to refer to Figure 1 An optical lens provided in Embodiment 1 of this application includes a first lens L1, a second lens L2, an aperture stop STO, a third lens L3, an IR filter, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and a flat glass CG arranged sequentially along the optical axis from the object side to the image side. The first lens L1 has positive optical power, with its object side being convex and its image side being concave; the second lens L2 has negative optical power, with its object side being concave and its image side being concave; the third lens L3 has positive optical power, with its object side being convex and its image side being convex; the fourth lens L4 has positive optical power, with its object side being convex and its image side being convex; the fifth lens L5 has negative optical power, with its object side being concave and its image side being concave; the sixth lens L6 has positive optical power, with its object side being convex; and the seventh lens L7 has negative optical power, with its object side being concave and its image side being convex.

[0091] The filter IR is positioned between the third lens L3 and the fourth lens L4, which helps to increase the distance between the filter IR and the sensor, reducing the ghost energy generated between them and improving the high-quality image quality of the optical imaging system. The fourth lens L4 and the fifth lens L5 form a cemented lens, which can effectively correct chromatic aberration, reduce the lens's off-center sensitivity, and balance aberrations, thus improving the image quality. The planar glass CG is positioned in the optical path between the seventh lens L7 and the image plane IMA, protecting the photosensitive chip in the imaging sensor. The optical physical parameters of the optical lens are shown in Table 1.

[0092] Table 1 shows the design values ​​of the optical physical parameters of the optical lens provided in Embodiment 1 of this application.

[0093]

[0094] In Table 1, the surface numbers are assigned according to the surface sequence of each lens; "1" represents the front surface of the first lens, "2" represents the rear surface of the first lens, and so on; "STO" represents the aperture stop of the optical lens; "IMA" represents the image plane of the optical lens; the radius of curvature represents the curvature of the lens surface, with a positive value indicating that the surface bends towards the image plane and a negative value indicating that the surface bends towards the object plane; "PL" indicates that the surface is flat and the radius of curvature is infinite; the thickness represents the distance between the central perpendicular axis of the current surface and the next surface; "material nd" is the refractive index, representing the ability of the material between the current surface and the next surface to deflect light; a blank space indicates that the current position is air and the refractive index is 1; "material vd" is the Abbe number, representing the dispersion characteristics of the material between the current surface and the next surface.

[0095] Furthermore, several performance tests were conducted on the optical lens provided in Embodiment 1, and the specific test results are as follows:

[0096] Figure 2 This application provides a ray fan diagram of an optical lens according to Embodiment 1. Ray fan diagrams are one of the commonly used evaluation methods by optical designers. For example... Figure 2 As shown, in a single image, the horizontal axis represents the normalized beam aperture, and the vertical axis represents the transverse aberration. Ideally, each curve should perfectly coincide with the horizontal axis, in which case all rays in that field of view focus at the same point on the image plane; the vertical axis in a single image can also represent the maximum dispersion range of the beam on the ideal image plane. The fan plot can not only reflect monochromatic aberrations of different wavelengths but also the magnitude of transverse chromatic aberration. Figure 2It can be seen that this optical system closely approximates the horizontal axis at all wavelengths in all fields of view, indicating that the transverse aberrations at each wavelength are well corrected. In addition, the curves of each color do not show significant dispersion, indicating that this optical system also has good correction for chromatic aberration, thus ensuring the imaging requirements of the optical lens provided in Embodiment 1 to form clear images across the entire wavelength range.

[0097] Figure 3 This is an axial aberration curve of an optical lens provided in Embodiment 1 of this application, for reference. Figure 3 The vertical direction represents the normalized aperture, with 0 indicating the optical axis and the vertical vertex representing the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focal point, in millimeters (mm). Different linear curves in the figure represent different wavelengths of image formation by the optical lens. Figure 3 It can be seen that the axial aberrations of different wavelengths are all controlled within the range of (-0.02mm, +0.03mm), indicating that the spherical aberration of the optical lens is well controlled at each wavelength, which can meet the requirements of wide spectrum applications.

[0098] Figure 4 A field curvature / distortion diagram of an optical lens provided in Embodiment 1 of this application, such as Figure 4 As shown, in the coordinate system on the left, the horizontal axis represents the field curvature of the optical lens, in mm; the vertical axis represents the normalized image height, without units. In the coordinate system on the right, the horizontal axis represents the distortion (F-Tan (Theta)), in %; the vertical axis represents the normalized image height, without units. Figure 4 As can be seen, the optical lens provided in this embodiment effectively controls field curvature in the visible light band, meaning that the difference in image quality between the center and the periphery is small during imaging. Simultaneously, the distortion of the optical lens is well corrected, resulting in minimal imaging distortion.

[0099] Example 2

[0100] Figure 5 This is a detailed structural diagram of an optical lens provided in Embodiment 2 of this application. (Reference) Figure 5Embodiment 2 of this application provides an optical lens, which includes a first lens L1, a second lens L2, an aperture stop STO, an IR filter, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and a flat glass CG arranged sequentially along the optical axis from the object side to the image side. The first lens L1 has positive optical power, with its object side being convex and its image side being concave; the second lens L2 has negative optical power, with its object side being concave and its image side being concave; the third lens L3 has positive optical power, with its object side being convex and its image side being convex; the fourth lens L4 has positive optical power, with its object side being convex and its image side being convex; the fifth lens L5 has negative optical power, with its object side being concave and its image side being concave; the sixth lens L6 has positive optical power, with its object side being convex; and the seventh lens L7 has negative optical power, with its object side being concave and its image side being convex.

[0101] The filter IR is positioned between the second lens L2 and the third lens L3, which helps to increase the distance between the filter IR and the sensor, reducing the ghost energy generated between them and improving the high-quality image quality of the optical imaging system. The fourth lens L4 and the fifth lens L5 form a cemented lens, which effectively corrects chromatic aberration, reduces the lens's eccentricity sensitivity, and balances aberrations, thus improving the image quality. The planar glass CG is positioned in the optical path between the seventh lens L7 and the image plane IMA, protecting the photosensitive chip in the imaging sensor. The optical physical parameters of the optical lenses are shown in Table 2.

[0102] Table 2 shows the design values ​​of the optical physical parameters of the optical lens provided in Embodiment 2 of this application.

[0103]

[0104] In Table 2, the surface numbers are assigned according to the surface sequence of each lens; "1" represents the front surface of the first lens, "2" represents the rear surface of the first lens, and so on; "STO" represents the aperture stop of the optical lens; "IMA" represents the image plane of the optical lens; the radius of curvature represents the curvature of the lens surface, with a positive value indicating that the surface bends towards the image plane and a negative value indicating that the surface bends towards the object plane; "PL" indicates that the surface is flat and the radius of curvature is infinite; the thickness represents the distance from the central perpendicular axis of the current surface to the next surface; "material nd" is the refractive index, representing the ability of the material between the current surface and the next surface to deflect light; a blank space indicates that the current position is air and the refractive index is 1; "material vd" is the Abbe number, representing the dispersion characteristics of the material between the current surface and the next surface.

[0105] Furthermore, several performance tests were conducted on the optical lens provided in Embodiment 2, and the specific test results are as follows:

[0106] Figure 6 This application provides a ray fan diagram of an optical lens according to Embodiment 2. Ray fan diagrams are one of the commonly used evaluation methods by optical designers. For example... Figure 6 As shown, in a single image, the horizontal axis represents the normalized beam aperture, and the vertical axis represents the transverse aberration. Ideally, each curve should perfectly coincide with the horizontal axis, in which case all rays in that field of view focus at the same point on the image plane; the vertical axis in a single image can also represent the maximum dispersion range of the beam on the ideal image plane. The fan plot can not only reflect monochromatic aberrations of different wavelengths but also the magnitude of transverse chromatic aberration. Figure 6 It can be seen that this optical system closely approximates the horizontal axis at all wavelengths in all fields of view, indicating that the transverse aberrations at each wavelength are well corrected. In addition, the curves of each color do not show significant dispersion, indicating that this optical system also has good correction for chromatic aberration, thus ensuring the imaging requirements of the optical lens provided in Embodiment 2 to form clear images across the entire wavelength range.

[0107] Figure 7 An axial aberration curve of an optical lens is provided in Embodiment 2 of this application, for reference. Figure 7 The vertical direction represents the normalized aperture, with 0 indicating the optical axis and the vertical vertex representing the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focal point, in millimeters (mm). Different linear curves in the figure represent different wavelengths of image formation by the optical lens. Figure 7 It can be seen that the axial aberrations of different wavelengths are all controlled within the range of (-0.01mm, +0.03mm), indicating that the spherical aberration of the optical lens is well controlled at each wavelength, which can meet the requirements of wide spectrum applications.

[0108] Figure 8 The field curvature / distortion diagram of an optical lens provided in Embodiment 2 of this application is as follows: Figure 8 As shown, in the coordinate system on the left, the horizontal axis represents the field curvature of the optical lens, in mm; the vertical axis represents the normalized image height, without units. In the coordinate system on the right, the horizontal axis represents the distortion (F-Tan (Theta)), in %; the vertical axis represents the normalized image height, without units. Figure 8 As can be seen, the optical lens provided in this embodiment effectively controls field curvature in the visible light band, meaning that the difference in image quality between the center and the periphery is small during imaging. Simultaneously, the distortion of the optical lens is well corrected, resulting in minimal imaging distortion.

[0109] Example 3

[0110] Figure 9This is a detailed structural diagram of an optical lens provided in Embodiment 3 of this application. (Reference) Figure 9 The optical lens provided in Embodiment 3 of this application includes a first lens L1, a second lens L2, an aperture stop STO, a filter IR, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and a flat glass CG arranged sequentially along the optical axis from the object side to the image side. The first lens L1 has positive optical power, with its object side being convex and its image side being concave; the second lens L2 has negative optical power, with its object side being concave and its image side being concave; the third lens L3 has positive optical power, with its object side being convex and its image side being convex; the fourth lens L4 has positive optical power, with its object side being convex and its image side being convex; the fifth lens L5 has negative optical power, with its object side being concave and its image side being concave; the sixth lens L6 has positive optical power, with its object side being convex; and the seventh lens L7 has negative optical power, with its object side being concave and its image side being convex.

[0111] The filter IR is positioned between the second lens L2 and the third lens L3, which helps to increase the distance between the filter IR and the sensor, reducing the ghost energy generated between them and improving the high-quality image quality of the optical imaging system. The fourth lens L4 and the fifth lens L5 form a cemented lens, which effectively corrects chromatic aberration, reduces the lens's eccentricity sensitivity, and balances aberrations, thus improving the image quality. The planar glass CG is positioned in the optical path between the seventh lens L7 and the image plane IMA, protecting the photosensitive chip in the imaging sensor. The optical physical parameters of the optical lenses are shown in Table 3.

[0112] Table 3 shows the design values ​​of the optical physical parameters of the optical lens provided in Embodiment 3 of this application.

[0113]

[0114] In Table 3, the surface numbers are assigned according to the surface sequence of each lens; "1" represents the front surface of the first lens, "2" represents the rear surface of the first lens, and so on; "STO" represents the aperture stop of the optical lens; "IMA" represents the image plane of the optical lens; the radius of curvature represents the curvature of the lens surface, with a positive value indicating that the surface bends towards the image plane and a negative value indicating that the surface bends towards the object plane; "PL" indicates that the surface is flat and the radius of curvature is infinite; the thickness represents the distance from the central perpendicular axis of the current surface to the next surface; "material nd" is the refractive index, representing the ability of the material between the current surface and the next surface to deflect light; a blank space indicates that the current position is air and the refractive index is 1; "material vd" is the Abbe number, representing the dispersion characteristics of the material between the current surface and the next surface.

[0115] Furthermore, several performance tests were conducted on the optical lens provided in Embodiment 3, and the specific test results are as follows:

[0116] Figure 10 This application provides a ray fan diagram of an optical lens according to Embodiment 3. Ray fan diagrams are one of the commonly used evaluation methods by optical designers. For example... Figure 10 As shown, in a single image, the horizontal axis represents the normalized beam aperture, and the vertical axis represents the transverse aberration. Ideally, each curve should perfectly coincide with the horizontal axis, in which case all rays in that field of view focus at the same point on the image plane; the vertical axis in a single image can also represent the maximum dispersion range of the beam on the ideal image plane. The fan plot can not only reflect monochromatic aberrations of different wavelengths but also the magnitude of transverse chromatic aberration. Figure 10 It can be seen that this optical system closely approximates the horizontal axis at all wavelengths in all fields of view, indicating that the transverse aberrations at each wavelength are well corrected. In addition, the curves of each color do not show significant dispersion, indicating that this optical system also has good correction for chromatic aberration, thus ensuring the imaging requirements of the optical lens 200 provided in Embodiment 2 to form a clear image across the entire wavelength range.

[0117] Figure 11 An axial aberration curve of an optical lens is provided for Embodiment 3 of this application, for reference. Figure 11 The vertical direction represents the normalized aperture, with 0 indicating the optical axis and the vertical vertex representing the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focal point, in millimeters (mm). Different linear curves in the figure represent different wavelengths of image formation by the optical lens. Figure 11 It can be seen that the axial aberrations of different wavelengths are all controlled within the range of (-0.01mm, +0.03mm), indicating that the spherical aberration of the optical lens is well controlled at each wavelength, which can meet the requirements of wide spectrum applications.

[0118] Figure 12 The field curvature / distortion diagram of an optical lens provided in Embodiment 3 of this application is as follows: Figure 12 As shown, in the coordinate system on the left, the horizontal axis represents the field curvature of the optical lens, in mm; the vertical axis represents the normalized image height, without units. In the coordinate system on the right, the horizontal axis represents the distortion (F-Tan (Theta)), in %; the vertical axis represents the normalized image height, without units. Figure 12 As can be seen, the optical lens provided in this embodiment effectively controls field curvature in the visible light band, meaning that the difference in image quality between the center and the periphery is small during imaging. Simultaneously, the distortion of the optical lens is well corrected, resulting in minimal imaging distortion.

[0119] Example 4

[0120] Figure 13 This is a detailed structural diagram of an optical lens provided in Embodiment 4 of this application. (Reference) Figure 13 Embodiment 4 of this application provides an optical lens comprising a first lens L1, a second lens L2, an aperture stop STO, a third lens L3, an IR filter, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7, and a flat glass CG arranged sequentially along the optical axis from the object side to the image side. The first lens L1 has positive optical power, with its object side being convex and its image side being concave; the second lens L2 has negative optical power, with its object side being concave and its image side being concave; the third lens L3 has positive optical power, with its object side being convex and its image side being convex; the fourth lens L4 has positive optical power, with its object side being convex and its image side being convex; the fifth lens L5 has negative optical power, with its object side being concave and its image side being concave; the sixth lens L6 has positive optical power, with its object side being convex; and the seventh lens L7 has negative optical power, with its object side being concave and its image side being convex.

[0121] The filter IR is positioned between the third lens L3 and the fourth lens L4, which helps to increase the distance between the filter IR and the sensor, reducing the ghost energy generated between them and improving the high-quality image quality of the optical imaging system. The fourth lens L4 and the fifth lens L5 form a cemented lens, which can effectively correct chromatic aberration, reduce the lens's off-center sensitivity, and balance aberrations, thus improving the image quality. The planar glass CG is positioned in the optical path between the seventh lens L7 and the image plane IMA, protecting the photosensitive chip in the imaging sensor. The optical physical parameters of the optical lens are shown in Table 4.

[0122] Table 4 shows the design values ​​of the optical physical parameters of the optical lens provided in Embodiment 4 of this application.

[0123]

[0124] In Table 4, the surface numbers are assigned according to the surface sequence of each lens; "1" represents the front surface of the first lens, "2" represents the rear surface of the first lens, and so on; "STO" represents the aperture stop of the optical lens; "IMA" represents the image plane of the optical lens; the radius of curvature represents the curvature of the lens surface, with a positive value indicating that the surface bends towards the image plane and a negative value indicating that the surface bends towards the object plane; "PL" indicates that the surface is flat and the radius of curvature is infinite; the thickness represents the distance from the central perpendicular axis of the current surface to the next surface; "material nd" is the refractive index, representing the ability of the material between the current surface and the next surface to deflect light; a blank space indicates that the current position is air and the refractive index is 1; "material vd" is the Abbe number, representing the dispersion characteristics of the material between the current surface and the next surface.

[0125] Furthermore, several performance tests were conducted on the optical lens provided in Embodiment 4, and the specific test results are as follows:

[0126] Figure 14 This application provides a ray fan diagram of an optical lens according to Embodiment 4. Ray fan diagrams are one of the commonly used evaluation methods by optical designers. For example... Figure 14 As shown, in a single image, the horizontal axis represents the normalized beam aperture, and the vertical axis represents the transverse aberration. Ideally, each curve should perfectly coincide with the horizontal axis, in which case all rays in that field of view focus at the same point on the image plane; the vertical axis in a single image can also represent the maximum dispersion range of the beam on the ideal image plane. The fan plot can not only reflect monochromatic aberrations of different wavelengths but also the magnitude of transverse chromatic aberration. Figure 14 It can be seen that this optical system closely approximates the horizontal axis at all wavelengths in all fields of view, indicating that the transverse aberrations at each wavelength are well corrected. In addition, the curves of each color do not show significant dispersion, indicating that this optical system also has good correction for chromatic aberration, thus ensuring the imaging requirements of the optical lens provided in Embodiment 4 to form clear images across the entire wavelength range.

[0127] Figure 15 An axial aberration curve of an optical lens is provided for Embodiment 4 of this application, with reference to... Figure 15 The vertical direction represents the normalized aperture, with 0 indicating the optical axis and the vertical vertex representing the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focal point, in millimeters (mm). Different linear curves in the figure represent different wavelengths of image formation by the L-shaped optical lens. Figure 15 It can be seen that the axial aberrations of different wavelengths are all controlled within the range of (-0.02mm, +0.03mm), indicating that the spherical aberration of the optical lens is well controlled at each wavelength, which can meet the requirements of wide spectrum applications.

[0128] Figure 16 The field curvature / distortion diagram of an optical lens provided in Embodiment 4 of this application is as follows: Figure 16 As shown, in the coordinate system on the left, the horizontal axis represents the field curvature of the optical lens, in mm; the vertical axis represents the normalized image height, without units. In the coordinate system on the right, the horizontal axis represents the distortion (F-Tan (Theta)), in %; the vertical axis represents the normalized image height, without units. Figure 16 As can be seen, the optical lens provided in this embodiment effectively controls field curvature in the visible light band, meaning that the difference in image quality between the center and the periphery is small during imaging. Simultaneously, the distortion of the optical lens is well corrected, resulting in minimal imaging distortion.

[0129] In summary, the optical physical parameters of the first lens to the seventh lens in Embodiments 1, 2, 3, and 4 of this application are shown in Table 5.

[0130] Table 5 Design values ​​of optical physical parameters for optical lenses

[0131]

[0132] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

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 positive optical power, and its object side is convex and its image side is concave. The second lens has negative optical power, and its object side is concave, as is its image side; The third lens has positive optical power, and its object side is convex, as is its image side; The fourth lens has positive optical power, and its object side is convex, as is its image side; The fifth lens has negative optical power, and its object side is concave, as is its image side; The sixth lens has positive optical power and its object-side surface is convex. The seventh lens has negative optical power, and its object side is concave while its image side is convex. It also includes a filter disposed between the second lens and the third lens; or, the filter is disposed between the third lens and the fourth lens; the fourth lens and the fifth lens form a cemented lens.

2. The optical lens according to claim 1, characterized in that, The distance dIR between the filter IR and the image plane and the total optical length TTL of the optical lens satisfy the following condition: 0.5 <dIR / TTL<0.82。 3. The optical lens according to claim 1, characterized in that, The optical power of the first to seventh lenses satisfies the following condition: ； ； ； ； ； ； ； in, The total optical power of the optical lens is [value missing]. , , , , , , The optical powers of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens are represented in sequence.

4. The optical lens according to claim 1, characterized in that, The refractive indices and Abbe numbers of the first to the seventh lenses satisfy the following conditions: ； ； ； ； ； ； ； ； ； ； ； ； ； ； Wherein, n1, n2, n3, n4, n5, n6, and n7 represent the refractive indices of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens, respectively, and v1, v2, v3, v4, v5, v6, and v7 represent the Abbe numbers of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens, respectively, in sequence.

5. The optical lens according to claim 1, characterized in that, An aperture stop is provided between the second lens and the third lens to limit the light beam.

6. The optical lens according to claim 1, characterized in that, The system focal length F of the optical lens and the total optical length TTL of the optical lens satisfy the following condition: TTL / F < 2.

4.

7. The optical lens according to claim 1, characterized in that, The maximum aperture D on the image side of the optical lens, the maximum field of view (FOV) of the optical lens, and the image height H corresponding to the maximum field of view (FOV) of the optical lens satisfy the following condition: D / H / FOV < 0.

05.

8. The optical lens according to claim 1, characterized in that, The optical back focal length (BFL) of the optical lens and the total optical length (TTL) of the optical lens satisfy the following condition: BFL / TTL > 0.

08.

9. The optical lens according to claim 2, characterized in that, The entrance pupil diameter ENPD of the optical lens and the total optical length TTL of the optical lens satisfy the following condition: ENPD / TTL > 0.

28.

10. The optical lens according to claim 1, characterized in that, The central radius of curvature R1 of the object side of the first lens and the central radius of curvature R2 of the image side of the first lens satisfy the following condition: R1 / R2 < 0.55.

Images