A low-distortion vehicle-mounted forward-looking optical system and a camera module used therein

Abstract

The present invention provides a low-distortion vehicle-mounted forward-looking optical system and a camera module used therein. The optical system is composed of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens in sequence along the optical axis from the object plane to the image plane. By rationally allocating the surface shape and optical focal length of each lens and using a hybrid optical system of spherical and aspherical surfaces, the optical system's recognition of distant objects in front is improved, while taking into account the advantages of low distortion, high-definition resolution, excellent temperature characteristics, and ultra-high pixels. Therefore, the system has great potential in the field of vehicle-mounted forward-looking vision.

Description

Technical Field

[0001] The present application relates to the field of optical imaging, and in particular to a low-distortion vehicle-mounted forward-looking optical system and a camera module used therein. Background Art

[0002] With technological advancements and the needs of socio-economic development, automotive assistance systems are becoming widely used and popularized. In-vehicle optical systems and modules are also widely used. Forward-looking optical lenses play a vital role in collision warning, lane departure warning, and pedestrian detection. To meet various driving needs, the system needs to improve its ability to identify distant objects ahead. This requires optical lenses with low distortion, high-definition resolution, excellent temperature characteristics, and ultra-high pixel count. However, existing forward-looking optical lenses do not meet these requirements. Summary of the Invention

[0003] In order to overcome the problem of low recognition of existing vehicle-mounted forward-looking optical lenses, the present application provides a low-distortion vehicle-mounted forward-looking optical system and a camera module applied thereto. By rationally distributing the surface shape and optical focal length of each lens and using a hybrid optical system of spherical and aspherical surfaces, the optical system's recognition of distant objects in front is improved, and it has low distortion, high-definition resolution, excellent temperature characteristics, and ultra-high pixel characteristics.

[0004] A low-distortion vehicle-mounted forward-view optical system, which is composed of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens in sequence from the object plane to the image plane along the optical axis;

[0005] The first lens has negative optical power, its object-side surface is concave, and its image-side surface is concave;

[0006] The second lens has positive optical power and its object side surface is convex;

[0007] The third lens has positive refractive power, its object-side surface is convex, and its image-side surface is convex;

[0008] The fourth lens has positive refractive power, its object-side surface is convex, and its image-side surface is convex;

[0009] The fifth lens has negative optical power, its object-side surface is concave, and its image-side surface is concave;

[0010] The sixth lens has positive refractive power, its object-side surface is convex, and its image-side surface is convex;

[0011] The seventh lens has negative refractive power and its object-side surface is concave.

[0012] Preferably, the optical system satisfies the following relationship:

[0013] 1.20<f / TTL*ImgH<3.50;

[0014] Wherein, f is the effective focal length of the optical system, TTL is the distance from the center of the object side of the first lens to the imaging surface of the optical lens on the optical axis, and ImgH is half the horizontal length of the effective pixel area on the imaging surface.

[0015] Preferably, the optical system meets the following conditions:

[0016] -25.0mm<f1<-8.0mm;

[0017] 8.0mm<f2<30.0mm;

[0018] 15.5mm<f3<25.5mm;

[0019] 5.0mm<f4<20.5mm;

[0020] -18.0mm<f5<-5.5mm;

[0021] 19.5mm<f6<14.5mm;

[0022] -90.0mm<f56<-65.0mm;

[0023] -20.0mm<f7<-12.0mm;

[0024] Among them, f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, f6 is the focal length of the sixth lens, f56 is the focal length of the cemented lens composed of the fifth and sixth lenses, and f7 is the focal length of the seventh lens.

[0025] Preferably, the optical system meets the following conditions:

[0026] -3.0<f1 / f<-0.8;

[0027] 1.0<f2 / f<5.5;

[0028] 0.9<f3 / f<3.0;

[0029] 4.5<f4 / f<10.5;

[0030] -1.5<f5 / f<-0.2;

[0031] -2.5<f6 / f<-0.8;

[0032] -7.5<f56 / f<-2.5;

[0033] -1.2<f7 / f<-0.3;

[0034] Wherein, f is the effective focal length of the optical system, f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, f6 is the focal length of the sixth lens, f56 is the focal length of the cemented lens consisting of the fifth and sixth lenses, and f7 is the focal length of the seventh lens.

[0035] Preferably, a curvature radius R22 of the image-side surface and a curvature radius R21 of the object-side surface of the second lens satisfy: |R22 / R21|≥3.

[0036] Preferably, the optical system satisfies the following condition: a curvature radius R71 of the object-side surface and a curvature radius R72 of the image-side surface of the seventh lens satisfy: 0.2≤|R71 / R72|≤0.45.

[0037] Preferably, the distance TTL from the center of the object-side surface of the first lens to the imaging surface of the optical lens on the optical axis and the focal length f of the optical lens satisfy the following condition: TTL / f≤5.

[0038] Preferably, the material refractive index Nd1 and the material Abbe number constant Vd1 of the first lens satisfy: 1.65<Nd1<2.00, 20.00<Vd1<60.00.

[0039] Preferably, the material refractive index Nd2 and the material Abbe number constant Vd2 of the second lens satisfy: 1.75<Nd2<2.00, 18.00<Vd2<30.00.

[0040] Preferably, the material refractive index Nd3 and the material Abbe number constant Vd3 of the third lens satisfy: 1.55<Nd3<1.67, 52.00<Vd3<65.00.

[0041] Preferably, the material refractive index Nd4 and the material Abbe number constant Vd4 of the fourth lens satisfy: 1.43<Nd4<1.63, 61.00<Vd4<95.00.

[0042] Preferably, the material refractive index Nd5 and the material Abbe number constant Vd5 of the fifth lens satisfy: 1.45<Nd5<1.95, 15.00<Vd5<35.00.

[0043] Preferably, the material refractive index Nd6 and the material Abbe number constant Vd6 of the sixth lens satisfy: 1.67<Nd6<1.80, 27.00<Vd6<50.00.

[0044] Preferably, the material refractive index Nd7 and the material Abbe number constant Vd7 of the seventh lens satisfy: 1.45<Nd7<1.50, 62.00<Vd7<75.00.

[0045] Preferably, the full field of view (FOV) of the optical system satisfies: 25.00<FOV<36.00.

[0046] Preferably, the optical system satisfies the following condition: the fifth lens and the sixth lens form a cemented lens.

[0047] On the other hand, an embodiment of the present application also provides a camera module, which includes at least an optical lens, and the above-mentioned low-distortion vehicle-mounted forward-looking optical system is installed in the optical lens.

[0048] Compared with the prior art, the present invention has the following advantages:

[0049] The low-distortion vehicle-mounted forward-looking optical system of the embodiment of the present invention and the camera module used therein are composed of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens in sequence along the optical axis from the object plane to the image plane. By rationally allocating the surface shape and optical focal length of each lens and using a hybrid optical system of spherical and aspherical surfaces, the optical system's recognition of distant objects in front is improved, while taking into account the advantages of low distortion, high-definition resolution, excellent temperature characteristics, and ultra-high pixels. Therefore, it has great potential in the field of vehicle-mounted forward-looking systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for describing the embodiments.

[0051] Figure 1 1 is a schematic structural diagram of an optical system or optical lens according to embodiment 1 of the present application;

[0052] Figure 2 is the astigmatism and distortion curve of the optical system or optical lens in Example 1 of the present application;

[0053] Figure 3 is a relative illumination curve of the optical system or optical lens of Example 1 of the present application;

[0054] Figure 4 is the axial chromatic aberration curve of the optical system or optical lens in Example 1 of the present application;

[0055] Figure 5 2 is a schematic structural diagram of an optical system or optical lens according to embodiment 2 of the present application;

[0056] Figure 6 is the astigmatism and distortion curve of the optical system or optical lens in Example 2 of the present application;

[0057] Figure 7 is a relative illumination curve of the optical system or optical lens of Example 2 of the present application;

[0058] Figure 8 It is the on-axis chromatic aberration curve of the optical system or optical lens in Example 2 of the present application. DETAILED DESCRIPTION

[0059] like Figure 1-8 As shown, the present application provides a low-distortion vehicle-mounted front-view optical system, which is composed of a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, and a seventh lens E7 in sequence from the object plane to the image plane along the optical axis;

[0060] The first lens E1 has negative refractive power, its object-side surface is concave, and its image-side surface is concave;

[0061] The second lens E2 has positive refractive power and its object-side surface is convex;

[0062] The third lens E3 has positive refractive power, its object-side surface is convex, and its image-side surface is convex;

[0063] The fourth lens E4 has positive refractive power, its object-side surface is convex, and its image-side surface is convex;

[0064] The fifth lens element E5 has negative refractive power, and its object-side surface and image-side surface are concave.

[0065] The sixth lens E6 has positive refractive power, its object-side surface is convex, and its image-side surface is convex;

[0066] The seventh lens element E7 has negative refractive power, and its object-side surface is concave.

[0067] An embodiment of the present invention provides a low-distortion automotive forward-view optical system. The optical system comprises, along the optical axis, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, and a seventh lens E7, sequentially arranged from the object plane to the image plane. By rationally allocating the surface shape and optical power of each lens and utilizing a hybrid optical system with spherical and aspherical surfaces, the optical system improves the recognition of distant objects ahead while simultaneously offering advantages such as low distortion, high-definition resolution, excellent temperature characteristics, and ultra-high pixel count. This system has enormous potential in the automotive forward-view field.

[0068] Preferably, the optical system satisfies the following relationship: 1.20<f / TTL*ImgH<3.50; wherein f is the effective focal length of the optical system, TTL is the distance from the center of the object-side surface of the first lens E1 to the imaging surface of the optical lens on the optical axis, and ImgH is half the horizontal length of the effective pixel area on the imaging surface. This relationship reflects the constraints of the optical lens in terms of field angle and thinness. When the above relationship is satisfied, the requirements of small head and thinness of the optical lens can be achieved on the basis of meeting the requirements of the optical lens, thereby improving the optical system's recognition of distant objects in front.

[0069] Preferably, the optical system satisfies the following conditions: -25.0 mm < f1 < -8.0 mm; 8.0 mm < f2 < 30.0 mm; 15.5 mm < f3 < 25.5 mm; 5.0 mm < f4 < 20.5 mm; -18.0 mm < f5 < -5.5 mm; 19.5 mm < f6 < 14.5 mm; -90.0 mm < f56 < -65.0 mm; -20.0 mm < f7 < -12.0 mm; wherein f1 is the focal length of the first lens E1, f2 is the focal length of the second lens E2, f3 is the focal length of the third lens E3, f4 is the focal length of the fourth lens E4, f5 is the focal length of the fifth lens E5, f6 is the focal length of the sixth lens E6, f56 is the focal length of the cemented lens formed by the fifth lens E5 and the sixth lens E6, and f7 is the focal length of the seventh lens E7. By rationally allocating the focal length of each lens, the optical system has high resolution, which reduces the size while also taking into account the advantages of high viewing angle clarity.

[0070] Preferably, the optical system satisfies the following condition: -3.0<f1 / f<-0.8, and by constraining the effective focal length ratio of the first lens E1 and the optical system to be within a reasonable range, the distortion of the system is controlled, so that the imaging center has a higher angular resolution;

[0071] Preferably, the optical system satisfies the following condition: 1.0<f2 / f<5.5, by constraining the effective focal length ratio of the second lens E2 and the optical system to be within a reasonable range, lens aberrations are optimized and imaging quality is improved;

[0072] Preferably, the optical system satisfies the following condition: 0.9<f3 / f<3.0. By constraining the effective focal length ratio of the third lens E3 and the optical system to be within a reasonable range, the spherical aberration of the system is fine-tuned and controlled, thereby effectively improving the imaging quality of the system.

[0073] Preferably, the optical system satisfies the following condition: 4.5<f4 / f<10.5, and the imaging quality of the system is effectively improved by reasonably controlling the ratio range of the fourth lens E4 and the effective focal length of the optical system;

[0074] Preferably, the optical system satisfies the following condition: -1.5<f5 / f<-0.2, by constraining the ratio of the optical power of the fifth lens E5 to the effective focal length of the optical system to be within a reasonable range, the imaging quality is improved, and the optical system has the characteristic of low distortion;

[0075] Preferably, the optical system satisfies the following condition: -2.5<f6 / f<-0.8, by constraining the effective focal length ratio of the sixth lens E6 and the optical system to a reasonable range, lens aberrations are optimized and analytical performance is improved;

[0076] Preferably, the optical system satisfies the following condition: -7.5<f56 / f<-2.5. By constraining the ratio of the combined focal length of the fifth lens element E5 and the sixth lens element E6 to the effective focal length of the optical lens, the focal powers of the fifth lens element E5 and the sixth lens element E6 can be properly distributed. This allows for a miniaturized design of the optical lens while also balancing the internal aberrations of the optical lens. This helps adjust the field curvature and astigmatism at the imaging edge of the optical lens, thereby ensuring the imaging quality of the optical lens for the surrounding environment.

[0077] Preferably, the optical system satisfies the following condition: -1.2<f7 / f<-0.3. By constraining the effective focal length ratio of the seventh lens E7 to the optical system within a reasonable range, good optical performance can be ensured, lens aberrations can be optimized, resolution performance can be improved, and viewing angle can be further guaranteed.

[0078] In the above, f is the effective focal length of the optical system, f1 is the focal length of the first lens E1, f2 is the focal length of the second lens E2, f3 is the focal length of the third lens E3, f4 is the focal length of the fourth lens E4, f5 is the focal length of the fifth lens E5, f6 is the focal length of the sixth lens E6, f56 is the focal length of the cemented lens consisting of the fifth lens E5 and the sixth lens E6, and f7 is the focal length of the seventh lens E7.

[0079] Preferably, the curvature radius R22 of the image-side surface and the curvature radius R21 of the object-side surface of the second lens E2 satisfy: |R22 / R21|≥3. This design is conducive to increasing the rear aperture diameter and increasing the light throughput of the system.

[0080] Preferably, the optical system satisfies the following condition: the curvature radius R71 of the object-side surface and the curvature radius R72 of the image-side surface of the seventh lens E7 satisfy: 0.2≤|R71 / R72|≤0.45. This design improves the resolving power of the lens.

[0081] Preferably, the distance from the center of the object-side surface of the first lens E1 to the imaging surface of the optical lens on the optical axis is TTL, and the focal length f of the optical lens satisfies: TTL / f≤5. This design can achieve miniaturization of the lens.

[0082] Preferably, the material refractive index Nd1 and the material Abbe number constant Vd1 of the first lens E1 satisfy the following conditions: 1.65<Nd1<2.00, 20.00<Vd1<60.00. This design can effectively reduce chromatic aberration, optimize lens aberration, and thus effectively improve the imaging quality of the system.

[0083] Preferably, the refractive index Nd2 and the Abbe number Vd2 of the material of the second lens E2 satisfy the following conditions: 1.75<Nd2<2.00, 18.00<Vd2<30.00. This design can effectively reduce chromatic aberration, optimize lens aberration, and thus effectively improve the imaging quality of the system.

[0084] Preferably, the refractive index Nd3 and the Abbe number Vd3 of the material of the third lens element E3 satisfy the following conditions: 1.55<Nd3<1.67, 52.00<Vd3<65.00. This design can ensure good optical performance, further ensure the viewing angle, improve the resolving power of the lens, and reduce distortion.

[0085] Preferably, the refractive index Nd4 and the Abbe number Vd4 of the material of the fourth lens element E4 satisfy the following conditions: 1.43<Nd4<1.63, 61.00<Vd4<95.00. This design can ensure good optical performance, further ensure the viewing angle, improve the resolving power of the lens, and reduce distortion.

[0086] Preferably, the refractive index Nd5 and the Abbe number Vd5 of the material of the fifth lens element E5 satisfy the following conditions: 1.45<Nd5<1.95, 15.00<Vd5<35.00. This design can ensure good optical performance, further ensure the viewing angle, improve the resolving power of the lens, and reduce distortion.

[0087] Preferably, the refractive index Nd6 and the Abbe number Vd6 of the sixth lens element E6 satisfy the following conditions: 1.67<Nd6<1.80, 27.00<Vd6<50.00. This design can effectively reduce chromatic aberration, optimize lens aberrations, and thereby effectively improve the imaging quality of the system.

[0088] Preferably, the material refractive index Nd7 and the material Abbe number Vd7 of the seventh lens element E7 satisfy the following conditions: 1.45<Nd7<1.50, 62.00<Vd7<75.00. This design can effectively reduce chromatic aberration, optimize lens aberrations, and thereby effectively improve the imaging quality of the system.

[0089] Preferably, the full field of view FOV of the optical system satisfies: 25.00<FOV<36.00. This design can reduce the total optical length and make the lens miniaturized. The optical system configured in the present invention has the advantages of low distortion, high-definition resolution, excellent temperature characteristics, and ultra-high pixels. It has a compact structure, is easy to process and install, and has good imaging resolution.

[0090] Preferably, the optical system meets the following conditions: the fifth lens E5 and the sixth lens E6 form a cemented lens, which, first, helps to eliminate the influence of chromatic aberration, reduce field curvature, and correct coma; second, eliminates the residual chromatic aberration to balance the overall chromatic aberration of the optical system; third, omits the air space between the two lenses, making the optical system compact as a whole and meeting the requirements of system miniaturization; fourth, reduces the sensitivity to tolerances such as tilt / eccentricity generated by the lens unit during the assembly process, and reduces the total length of the lens.

[0091] Specifically, as a preferred embodiment of the present invention but not limiting, refer to Figures 1 to 4 The optical imaging lens of Example 1 of the present application is described as follows: Figure 1 As shown, the optical imaging lens according to an exemplary embodiment of the present application is composed of a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, a filter E8 and an imaging surface S16 in sequence from the object plane to the image plane along the optical axis.

[0092] The effective focal length f of the optical system, the on-axis distance TTL from the object-side surface S1 of the first lens element E1 to the imaging surface S16, and half the horizontal length of the effective pixel area on the imaging surface ImgH satisfy the following relationship: f / TTL*ImgH=1.945. The curvature radius R22 of the image-side surface S4 of the second lens element E2 and the curvature radius of the object-side surface S3 satisfy the following relationship: |R22 / R21|=9.19. The distance TTL on the optical axis from the center of the object-side surface S1 of the first lens element E1 to the imaging surface S16 of the optical lens and the focal length f of the optical lens satisfy the following relationship: TTL / f=2.073. The curvature radius R71 of the object-side surface S12 of the seventh lens element E7 and the curvature radius R72 of the image-side surface S13 satisfy the following relationship: |R71 / R72|=0.28.

[0093] The first lens E1 has negative power, with its object-side surface S1 being concave and its image-side surface S2 being concave. The second lens E2 has positive power, with its object-side surface S3 being convex. The third lens E3 has positive power, with its object-side surface S5 being convex and its image-side surface S6 being convex. The fourth lens E4 has positive power, with its object-side surface S7 being convex and its image-side surface S8 being convex. The fifth lens E5 has negative power, with its object-side surface S8 being concave and its image-side surface S9 being concave. The sixth lens E6 has positive power, with its object-side surface S10 being convex and its image-side surface S11 being convex. The seventh lens E7 has negative power, with its object-side surface S12 being concave. The fifth lens E5 and the sixth lens E6 are a cemented lens. The filter E8 has an object-side surface S14 and an image-side surface S15. Light from the object sequentially passes through surfaces S1 to S15 and is ultimately imaged on the imaging surface S16.

[0094] Table 1 shows the surface type, curvature radius, thickness, and material of each lens of the optical imaging lens of the embodiment, wherein the units of the curvature radius and thickness are both millimeters (mm).

[0095] Table 1: Basic parameters of the optical system of Example 1

[0096] Face number Surface type Curvature radius (mm) Thickness (mm) Material OBJ spherical surface endless endless S1 spherical surface -16.520 3.76 1.65,33.16 S2 spherical surface 30.758 0.51 S3 spherical surface 15.924 2.85 1.95,21.79 S4 spherical surface 146.254 0.20 STO spherical surface Infinity 0.25 S6 Aspheric 17.179 3.61 1.60,65.82 S7 Aspheric -38.782 0.12 S8 spherical surface 19.127 4.94 1.62,63.41 S9 spherical surface -9.025 1.21 1.78,23.62 S10 Aspheric 21.231 3.16 S11 Aspheric 15.452 4.03 1.85,43.00 S12 Aspheric -30.701 2.21 S13 Aspheric -7.973 0.96 1.35,73.39 S14 Aspheric 28.968 1.30 S15 spherical surface endless 0.80 1.49,66.20 S16 spherical surface endless 1.89 S17 spherical surface endless

[0097] In Table 1, either the object side or the image side of the third lens E3 or the sixth lens E6 is an aspherical surface. The surface shape of each aspherical lens can be defined by, but not limited to, the following aspherical surface formula:

[0098]

[0099] Where x is the distance from the corresponding point on the aspheric surface to the plane tangent to the vertex of the surface, h is the distance from the corresponding point on the aspheric surface to the optical axis, c is the curvature of the aspheric vertex, k is the conic coefficient, and Ai is the coefficient corresponding to the i-th higher-order term in the aspheric surface shape formula. Table 2 shows the conic coefficients and higher-order coefficients A4, A6, A8, A10, A12, A14, and A16 for various aspheric surfaces that can be used in Example 1.

[0100] Table 2: Aspheric surface related values ​​of the lens surface of Example 1

[0101] Surface number K A4 A6 A8 A10 A12 6 -3.06E+00 -8.98E-05 -2.36E-06 1.56E-09 -8.77E-10 0 7 14.40E+00 -1.49E-04 -1.70E-06 -1.57E-08 -8.04E-11 0 11 2.57E+00 -1.87E-04 -3.37E-06 -1.01E-08 -8.95E-12 -3.61E-11 12 -198.19E+00 -2.96E-04 5.51E-06 -1.42E-07 -2.15E-09 4.72E-11

[0102] Figure 2 The astigmatism and distortion curves of the optical imaging lens of Example 1 are shown. Astigmatism represents meridional image curvature and sagittal image curvature; distortion represents the distortion magnitude corresponding to different image heights.

[0103] Figure 3 The relative illumination curve of the optical imaging lens of Example 1 is shown, which represents the ratio of the illumination at different coordinate points on the image plane to the illumination at the center point.

[0104] Figure 4 The axial chromatic aberration curve of the optical imaging lens of Example 1 is shown, which indicates that the light of different wavelengths deviates from the focal point after passing through the lens. Figures 1 to 4 It can be seen that the optical imaging lens provided in Example 1 can achieve good imaging quality and realize a high-performance design.

[0105] Specifically, as a preferred embodiment of the present invention but not limiting, refer to Figures 5 to 8 Describe the optical imaging lens of Example 2 of the present application, such as Figure 5As shown, the optical imaging lens according to an exemplary embodiment of the present application is composed of a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a seventh lens E7, a filter E8 and an imaging surface S16 in sequence from the object plane to the image plane along the optical axis.

[0106] The effective focal length f of the optical system, the on-axis distance TTL between the object-side surface S1 of the first lens element E1 and the imaging surface S16, and half the horizontal length of the effective pixel area on the imaging surface ImgH satisfy the following relationship: f / TTL*ImgH=1.995. The curvature radius R22 of the image-side surface S4 of the second lens element E2 and the curvature radius of the object-side surface S3 satisfy the following relationship: |R22 / R21|=3.54. The distance TTL on the optical axis from the center of the object-side surface S1 of the first lens element E1 to the imaging surface S16 of the optical lens element and the focal length f of the optical lens satisfy the following relationship: TTL / f=2.021. The curvature radius R71 of the object-side surface S12 of the seventh lens element E7 and the curvature radius R72 of the image-side surface S13 satisfy the following relationship: |R71 / R72|=0.35.

[0107] The first lens E1 has negative power, with its object-side surface S1 being concave and its image-side surface S2 being concave. The second lens E2 has positive power, with its object-side surface S3 being convex. The third lens E3 has positive power, with its object-side surface S5 being convex and its image-side surface S6 being convex. The fourth lens E4 has positive power, with its object-side surface S7 being convex and its image-side surface S8 being convex. The fifth lens E5 has negative power, with its object-side surface S8 being concave and its image-side surface S9 being concave. The sixth lens E6 has positive power, with its object-side surface S10 being convex and its image-side surface S11 being convex. The seventh lens E7 has negative power, with its object-side surface S12 being concave. The fifth lens E5 and the sixth lens E6 are a cemented lens. The optical filter E8 has an object-side surface S14 and an image-side surface S15. Light from the object sequentially passes through surfaces S1 to S15 and is ultimately imaged on the imaging surface S16.

[0108] Table 3 shows the surface type, curvature radius, thickness, and material of each lens of the optical imaging lens of Example 2, where the units of curvature radius and thickness are both millimeters (mm).

[0109] Table 3: Basic parameters of the optical system of Example 2

[0110] Face number Surface type Curvature radius (mm) Thickness (mm) Material OBJ spherical surface endless endless S1 spherical surface -18.068 1.75 1.66,33.16 S2 spherical surface 18.068 0.18 S3 spherical surface 16.949 3.28 1.81,23.79 S4 spherical surface -60.051 0.00 STO spherical surface Infinity 0.36 S6 Aspheric 17.765 4.62 1.65,64.82 S7 Aspheric -41.371 0.10 S8 spherical surface 29.793 4.23 1.55,69.34 S9 spherical surface -11.148 1.16 1.75,25.62 S10 Aspheric 42.581 3.40 S11 Aspheric 13.892 4.47 1.74,48.59 S12 Aspheric -41.244 3.05 S13 Aspheric -8.349 0.87 1.43,70.44 S14 Aspheric 23.819 2.70 S15 spherical surface endless 0.80 1.50,65.20 S16 spherical surface endless 0.03 S17 spherical surface endless

[0111] In Table 3, both the object side and the image side of the third lens E3 and the sixth lens E6 are aspherical surfaces. The surface shape of each aspherical lens can be defined by, but not limited to, the following aspherical surface formula:

[0112]

[0113] Where x is the distance from the corresponding point on the aspheric surface to the plane tangent to the vertex of the surface, h is the distance from the corresponding point on the aspheric surface to the optical axis, c is the curvature of the aspheric vertex, k is the conic coefficient, and Ai is the coefficient corresponding to the i-th higher-order term in the aspheric surface shape formula. Table 4 shows the conic coefficients and higher-order coefficients A4, A6, A8, A10, A12, A14, and A16 for various aspheric surfaces that can be used in Example 2.

[0114] Table 4: Aspheric surface related values ​​of the lens surface of Example 2

[0115] Surface number K A4 A6 A8 A10 A12 6 -3.06E+00 -8.98E-05 -2.36E-06 1.56E-09 -8.77E-10 0 7 14.40E+00 -1.49E-04 -1.70E-06 -1.57E-08 -8.04E-11 0 11 2.57E+00 -1.87E-04 -3.37E-06 -1.01E-08 -8.95E-12 -3.61E-11 12 -198.19E+00 -2.96E-04 5.51E-06 -1.42E-07 -2.15E-09 4.72E-11

[0116] Figure 6 The astigmatism and distortion curves of the optical imaging lens of Example 2 are shown. Astigmatism represents meridional image curvature and sagittal image curvature; distortion represents the distortion magnitude corresponding to different image heights.

[0117] Figure 7 The relative illumination curve of the optical imaging lens of Example 2 is shown, which represents the ratio of the illumination at different coordinate points on the image plane to the illumination at the center point.

[0118] Figure 8 The axial chromatic aberration curve of the optical imaging lens of Example 2 is shown, which indicates that the light of different wavelengths deviates from the focal point after passing through the lens. Figures 5 to 8 It can be seen that the optical imaging lens provided in Example 2 can achieve good imaging quality and realize a high-performance design.

[0119] A camera module includes at least an optical lens, in which the above-mentioned low-distortion vehicle-mounted forward-looking optical system is installed. The optical system is composed of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens in sequence from the object plane to the image plane along the optical axis. By rationally allocating the surface shape and optical focal length of each lens and using a hybrid optical system of spherical and aspherical surfaces, the optical system's recognition of distant objects in front is improved, while taking into account the advantages of low distortion, high-definition resolution, excellent temperature characteristics, and ultra-high pixels. It has great potential in the field of vehicle-mounted forward-looking.

[0120] The above descriptions are provided in conjunction with specific content to provide one or more embodiments, and the specific implementation of the present invention is not limited to these descriptions. Any similarity or similarity with the methods, structures, etc. of the present invention, or any technical deduction or substitution based on the concept of the present invention, shall be considered within the scope of protection of the present invention.

Claims

1. A low-distortion automotive front-view optical system, comprising, in order from the object plane to the image plane along the optical axis, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens, characterized in that: The first lens has negative optical power, its object-side surface is concave, and its image-side surface is concave; The second lens has positive optical power and its object side surface is convex; The third lens has positive refractive power, its object-side surface is convex, and its image-side surface is convex; The fourth lens has positive refractive power, its object-side surface is convex, and its image-side surface is convex; The fifth lens has negative optical power, its object-side surface is concave, and its image-side surface is concave; The sixth lens has positive refractive power, its object-side surface is convex, and its image-side surface is convex; The seventh lens has negative optical power, its object-side surface is concave, and its image-side surface is concave; The optical system satisfies the following relationship: 1.20mm<f / TTL*ImgH<3.50mm; Where f is the effective focal length of the optical system, TTL is the distance from the center of the object side of the first lens to the imaging plane of the optical lens on the optical axis, and ImgH is half the horizontal length of the effective pixel area on the imaging plane; The optical system meets the following conditions: -25.0mm<f1<-8.0mm; 8.0mm<f2<30.0mm; 15.5mm<f3<25.5mm; 5.0mm<f4<20.5mm; -18.0mm<f5<-5.5mm; 19.5mm<f6<14.5mm; -90.0mm<f56<-65.0mm; -20.0mm<f7<-12.0mm; Among them, f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, f6 is the focal length of the sixth lens, f56 is the focal length of the cemented lens composed of the fifth and sixth lenses, and f7 is the focal length of the seventh lens.

2. The low-distortion vehicle-mounted forward-looking optical system according to claim 1, characterized in that: The optical system meets the following conditions: -3.0<f1 / f<-0.8; 1.0<f2 / f<5.5; 0.9<f3 / f<3.0; 4.5<f4 / f<10.5; -1.5<f5 / f<-0.2; -7.5<f56 / f<-2.5; -1.2<f7 / f<-0.3; Wherein, f is the effective focal length of the optical system, f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, f56 is the focal length of the cemented lens consisting of the fifth and sixth lenses, and f7 is the focal length of the seventh lens.

3. The low-distortion vehicle-mounted forward-looking optical system according to any one of claims 1 to 2, characterized in that: A curvature radius R22 of the image-side surface of the second lens and a curvature radius R21 of the object-side surface of the second lens satisfy: |R22 / R21|≥3.

4. The low-distortion vehicle-mounted forward-looking optical system according to any one of claims 1 to 2, characterized in that: The optical system satisfies the following condition: a curvature radius R71 on the object-side surface and a curvature radius R72 on the image-side surface of the seventh lens satisfy the following relationship: 0.2≤|R71 / R72|≤0.

45.

5. The low-distortion vehicle-mounted forward-looking optical system according to any one of claims 1 to 2, characterized in that: The distance between the center of the object-side surface of the first lens and the imaging surface of the optical lens on the optical axis is TTL, and the focal length f of the optical lens satisfies the following: TTL / f≤5.

6. The low-distortion vehicle-mounted forward-looking optical system according to any one of claims 1-2, characterized in that: The material refractive index Nd1 and the material Abbe number Vd1 of the first lens satisfy the following conditions: 1.65<Nd1<2.00, 20.00<Vd1<60.00; The material refractive index Nd2 and the material Abbe number Vd2 of the second lens satisfy the following conditions: 1.75<Nd2<2.00, 18.00<Vd2<30.00; The refractive index Nd3 and Abbe number Vd3 of the third lens element satisfy the following conditions: 1.55<Nd3<1.67, 52.00<Vd3<65.00; The material refractive index Nd4 and the material Abbe number Vd4 of the fourth lens satisfy the following conditions: 1.43<Nd4<1.63, 61.00<Vd4<95.00; The refractive index Nd5 and Abbe number Vd5 of the material of the fifth lens satisfy the following conditions: 1.45<Nd5<1.95, 15.00<Vd5<35.00; The refractive index Nd6 and Abbe number Vd6 of the sixth lens element satisfy the following conditions: 1.67<Nd6<1.80, 27.00<Vd6<50.00; The material refractive index Nd7 and the material Abbe number Vd7 of the seventh lens satisfy: 1.45<Nd7<1.50, 62.00<Vd7<75.

00.

7. The low-distortion vehicle-mounted forward-looking optical system according to any one of claims 1 to 2, characterized in that: The full field of view FOV of the optical system satisfies: 25.00°<FOV<36.00°.

8. The low-distortion vehicle-mounted forward-looking optical system according to any one of claims 1 to 2, characterized in that: This optical system satisfies the following condition: the fifth lens and the sixth lens form a cemented lens.

9. A camera module, comprising at least an optical lens, characterized in that: The optical lens is equipped with the low-distortion vehicle-mounted forward-looking optical system according to any one of claims 1 to 8.

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