Low-distortion wide-angle high-resolution vehicle-mounted forward-looking optical system and camera module applied thereto

Abstract

This invention provides a low-distortion, wide-angle, high-resolution automotive forward-looking optical system and its application camera module, mainly composed of seven lenses. The first lens has negative optical power and its image-side surface is concave; the second lens has negative optical power and its object-side surface is concave, as is its image-side surface; the third lens has positive optical power and its object-side surface is convex, as is its image-side surface; the fourth lens has positive optical power and its object-side surface is convex, as is its image-side surface; the fifth lens has optical power; the sixth lens has optical power; and the seventh lens has positive optical power and its object-side surface is convex. Through the reasonable combination of lens shape and optical power, it has the advantages of low distortion, wide angle, and high resolution. At the same time, the wide angle can increase the amount of light entering the optical system and achieve higher image quality.

Description

Technical Field

[0001] This application relates to the field of optical imaging, and in particular to a low-distortion wide-angle high-resolution optical system for use in automotive forward-looking applications. Background Technology

[0002] With the rapid development of camera lenses in the automotive field, people have increasingly higher requirements for lenses during driving, demanding not only a wide field of view but also high clarity. However, current lenses on the market offer narrow fields of view and low resolution during driving, failing to meet users' higher demands. To satisfy customer requirements, lenses need to have a wide field of view, and to achieve high resolution, the field of view of the optical system needs to be increased, which will give them a greater competitive edge in the market. Summary of the Invention

[0003] This application aims to provide a low-distortion, wide-angle, high-resolution automotive forward-looking optical system, which has the advantages of low distortion, wide angle, and high resolution. At the same time, the wide angle can increase the amount of light entering the optical system and achieve higher imaging quality.

[0004] A low-distortion wide-angle high-resolution vehicle-mounted forward-looking optical system includes, along the optical axis from the object plane to the image plane, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens.

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

[0006] The second lens has negative optical power, and its object side is concave, as is its image side;

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

[0008] The fourth lens has positive optical power, and its object side is convex, and its image side is convex.

[0009] The fifth lens has optical power;

[0010] The sixth lens has optical power;

[0011] The seventh lens has positive optical power and its object-side surface is convex.

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

[0013] 0.42 <f / TTL*ImagH<0.65;

[0014] Where f is the effective focal length of the optical system, TTL is the on-axis distance from the object side of the first lens to the imaging plane, and ImagH is half the diagonal length of the effective pixel area on the imaging plane.

[0015] Preferably, the optical system satisfies the following relationship:

[0016] -10.0 <f1<-3.2;

[0017] -15.0 <f2<-4.1;

[0018] 6.3 <f3<12.8;

[0019] 5.3 <f4<15.0;

[0020] -6.8 <f5<8.5;

[0021] -7.9 <f6<8.5;

[0022] 8.2 <f7<50.0;

[0023] Where 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, and f7 is the focal length of the seventh lens.

[0024] Preferably, the optical system satisfies the following relationship:

[0025] -2.5 <f1 / f<0;

[0026] -5.0 <f2 / f<-0.5;

[0027] 2.0 <f3 / f<5.0;

[0028] 1.3 <f4 / f<3.5;

[0029] -3.8 <f5 / f<3.2;

[0030] -3.1 <f6 / f<3.0;

[0031] 1.2 <f7 / f<15.0;

[0032] Where f is the focal length of the entire 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, and f7 is the focal length of the seventh lens.

[0033] Preferably, the refractive index Nd1 and Abbe constant Vd1 of the first lens material satisfy: 1.65 <Nd1<2.00,25<Vd1<60。

[0034] Preferably, the refractive index Nd2 and Abbe number Vd2 of the second lens material satisfy: 1.55 <Nd2<1.80,30<Vd2<55。

[0035] Preferably, the refractive index Nd3 and Abbe number Vd3 of the third lens material satisfy: 1.60 <Nd3<1.95,17.5<Vd3<55。

[0036] Preferably, the refractive index Nd4 and Abbe number Vd4 of the fourth lens material satisfy: 1.44 <Nd4<2.00,25<Vd4<95。

[0037] Preferably, the refractive index Nd5 and Abbe number Vd5 of the fifth lens material satisfy: 1.43 <Nd5<2.00,17.5<Vd5<95。

[0038] Preferably, the refractive index Nd6 and Abbe number Vd6 of the sixth lens satisfy: 1.43. <Nd6<2.00,17.5<Vd6<95。

[0039] Preferably, the refractive index Nd7 and Abbe number Vd7 of the seventh lens material satisfy: 1.49 <Nd7<2.00,20<Vd7<82。

[0040] Preferably, the first lens, the second lens, the third lens, the fifth lens, and the sixth lens are spherical lenses, and the fourth lens and the seventh lens are aspherical glass lenses.

[0041] On the other hand, this application embodiment also provides a camera module, which includes at least an optical lens, and the aforementioned low-distortion wide-angle high-resolution vehicle-mounted forward-looking optical system is installed in the optical lens.

[0042] Compared with the prior art, the beneficial effects of this application are as follows:

[0043] This invention provides a low-distortion, wide-angle, high-resolution automotive forward-looking optical system and its application camera module, mainly composed of seven lenses. The first lens has negative optical power and its image-side surface is concave; the second lens has negative optical power and its object-side surface is concave, as is its image-side surface; the third lens has positive optical power and its object-side surface is convex, as is its image-side surface; the fourth lens has positive optical power and its object-side surface is convex, as is its image-side surface; the fifth lens has optical power; the sixth lens has optical power; and the seventh lens has positive optical power and its object-side surface is convex. Through the reasonable combination of lens shape and optical power, it has the advantages of low distortion, wide angle, and high resolution. At the same time, the wide angle can increase the amount of light entering the optical system and achieve higher image quality. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0045] Figure 1 This is a schematic diagram of the structure of the optical system or camera module in Embodiment 1 of this application;

[0046] Figure 2 This refers to the astigmatism and distortion curves of the optical system or camera module in Embodiment 1 of this application;

[0047] Figure 3 This is the color difference curve of the optical system or camera module in Embodiment 1 of this application;

[0048] Figure 4 This is a schematic diagram of the structure of the optical system or camera module in Embodiment 2 of this application;

[0049] Figure 5 This refers to the astigmatism and distortion curves of the optical system or camera module in Embodiment 2 of this application;

[0050] Figure 6 This is the color difference curve of the optical system or camera module in Embodiment 2 of this application;

[0051] Figure 7 This is a schematic diagram of the structure of the optical system or camera module in Embodiment 3 of this application;

[0052] Figure 8 This refers to the astigmatism and distortion curves of the optical system or camera module in Embodiment 3 of this application;

[0053] Figure 9 This is the color difference curve of the optical system or camera module in Embodiment 3 of this application. Detailed Implementation

[0054] like Figure 1-9 As shown, this application provides a low-distortion wide-angle, high-resolution automotive forward-looking optical system, including a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and a filter arranged sequentially from the object side. The first, second, third, fifth, and sixth lenses are spherical lenses, while the fourth and seventh lenses are aspherical glass lenses. The first lens has negative optical power and its image-side surface is concave; the second lens has negative optical power and its object-side surface is concave, as is its image-side surface; the third lens has positive optical power and its object-side surface is convex, as is its image-side surface; the fourth lens has positive optical power and its object-side surface is convex, as is its image-side surface; the fifth lens has optical power; the sixth lens has optical power; and the seventh lens has positive optical power and its object-side surface is convex.

[0055] The optical system of the embodiment of the present application mainly consists of seven lenses. Through the reasonable combination of the lens shape and optical power, it has the advantages of low distortion, wide angle, and high resolution. At the same time, the wide angle can increase the light input of the optical system and higher imaging quality.

[0056] Further, the optical system satisfies the following relationship: 0.42 < f / TTL * ImagH < 0.65; where f is the effective focal length of the optical imaging system, TTL is the axial distance from the object side surface of the first lens to the imaging surface, and ImagH is half of the diagonal length of the effective pixel area on the imaging surface. This relational expression reflects the constraint situation of the optical lens in terms of the field angle and thin and light characteristics. When the above relational expression is satisfied, it can meet the market demand for the small head and thin and light characteristics of the optical lens while ensuring that the optical lens has a wide angle. When exceeding the upper limit of the relational expression, on the basis of ensuring that the field angle of the optical lens is wide, f / TTL * ImagH is further reduced, which will excessively compress the thin and light characteristics of the optical lens and is not conducive to the improvement of the performance of the optical lens. When lower than the lower limit of the relational expression, the thin and light characteristics of the optical lens are insufficient, which is not conducive to the miniaturized design of the optical lens.

[0057] Further, each lens of the optical system satisfies the following conditions: (1) -10.0 < f1 < -3.2; (2) -15.0 < f2 < -4.1; (3) 6.3 < f3 < 12.8; (4) 5.3 < f4 < 15.0; (5) -6.8 < f5 < 8.5; (6) -7.9 < f6 < 8.5; (7) 8.2 < f7 < 50.0; where 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, and f7 is the focal length of the seventh lens. By reasonably controlling the effective focal lengths of each lens of the optical system, the optical system can satisfy a large field angle while restricting the effective diameter of the components, controlling the size of the overall optical system, and adjusting the light incident angle, which is beneficial to correcting the system aberration.

[0058] Furthermore, each lens of the optical system satisfies the following conditions: (1) -2.5 < f1 / f < 0; (2) -5.0 < f2 / f < -0.5; (3) 2.0 < f3 / f < 5.0; (4) 1.3 < f4 / f < 3.5; (5) -3.8 < f5 / f < 3.2; (6) -3.1 < f6 / f < 3.0; (7) 1.2 < f7 / f < 15.0; where f is the focal length of the entire 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, and f7 is the focal length of the seventh lens. By limiting the ratio of the effective focal length of each lens to the effective focal length of the optical system, the optical system obtains a reasonable light deflection angle, effectively reduces the sensitivity to component tolerances, and improves system aberrations, achieving higher imaging quality.

[0059] Furthermore, the refractive index Nd1 and Abbe number Vd1 of the material of the first lens satisfy: 1.65 < Nd1 < 2.00, 25 < Vd1 < 60; the refractive index Nd2 and Abbe number Vd2 of the material of the second lens satisfy: 1.55 < Nd2 < 1.80, 30 < Vd2 < 55; the refractive index Nd3 and Abbe number Vd3 of the material of the third lens satisfy: 1.60 < Nd3 < 1.95, 17.5 < Vd3 < 55; the refractive index Nd4 and Abbe number Vd4 of the material of the fourth lens satisfy: 1.44 < Nd4 < 2.00, 25 < Vd4 < 95; the refractive index Nd5 and Abbe number Vd5 of the material of the fifth lens satisfy: 1.43 < Nd5 < 2.00, 17.5 < Vd5 < 95; the refractive index Nd6 and Abbe number Vd6 of the material of the sixth lens satisfy: 1.43 < Nd6 < 2.00, 17.5 < Vd6 < 95; the refractive index Nd7 and Abbe number Vd7 of the material of the seventh lens satisfy: 1.49 < Nd7 < 2.00, 20 < Vd7 < 82. By limiting the relationship between the refractive index and Abbe number of each lens, it is beneficial to reduce aberrations and improve the image quality of the high-pixel optical system.

[0060] Example 1

[0061] The following refers to Figures 1 to 3 Describe the optical imaging lens according to Embodiment 1 of the present application. Figure 1 Fig. shows a schematic structural diagram of the optical imaging lens according to Embodiment 1 of the present application.

[0062] As Figure 1 shown, the optical imaging lens according to the exemplary embodiment of the present application sequentially includes, along the optical axis from the object side to the image side: 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.

[0063] The first lens E1 has negative optical power, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has negative optical power, with its object-side surface S3 being concave and its image-side surface S4 being concave. The third lens E3 has positive optical power, with its object-side surface S4 being convex and its image-side surface S5 being convex. The fourth lens E4 has positive optical power, with its object-side surface S6 being convex and its image-side surface S7 being convex. The fifth lens E5 has negative optical power, with its object-side surface S9 being concave and its image-side surface S10 being concave. The sixth lens E6 has positive optical power, with its object-side surface S10 being convex and its image-side surface S11 being convex. The seventh lens E7 has positive optical power, with its object-side surface S12 being convex and its image-side surface S13 being concave. The filter E8 has an object-side surface S14 and an image-side surface S15. Light from the object passes sequentially through surfaces S1 to S15 and is finally imaged onto the imaging surface S16.

[0064] Table 1 shows the surface type, radius of curvature, thickness, and material of each lens in the optical imaging lens of Example 1, wherein the units for radius of curvature and thickness are millimeters (mm).

[0065] Table 1

[0066]

[0067] In Table 2, the object-side surface and image-side surface of either the fourth lens E4 or the seventh lens E7 are aspherical. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formulas:

[0068]

[0069] Where x is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, h is the distance from the corresponding point on the aspherical surface to the optical axis, c is the curvature of the vertex of the aspherical surface, k is the conic coefficient, and Ai is the coefficient corresponding to the i-th higher-order term in the aspherical surface shape formula. Table 2 gives the conic coefficients and higher-order coefficients A4, A6, A8, A10, and A12 of each aspherical surface that can be used in the first embodiment.

[0070] Table 2

[0071]

[0072] Figure 2 The astigmatism and distortion curves of the optical imaging lens of Example 1 are shown. Astigmatism represents the meridional image plane curvature and the sagittal image plane curvature; distortion represents the distortion magnitude corresponding to different image heights.

[0073] Figure 3 The chromatic aberration curve of the optical imaging lens of Example 1 is shown, which represents the chromatic aberration shift at different wavelengths.

[0074] The optical imaging lens given in Example 1 can achieve good imaging quality.

[0075] Example 2

[0076] The following is for reference Figures 4 to 6 Describes an optical imaging lens according to Embodiment 2 of this application. Figure 4 A schematic diagram of the structure of an optical imaging lens according to Embodiment 2 of this application is shown.

[0077] like Figure 4 As shown, the optical imaging lens according to an exemplary embodiment of this application includes, in sequence along the optical axis from the object side to the image side: 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.

[0078] The first lens E1 has negative optical power, with its object-side surface S1 being concave and its image-side surface S2 being concave. The second lens E2 has negative optical power, with its object-side surface S3 being concave and its image-side surface S4 being concave. The third lens E3 has positive optical power, with its object-side surface S4 being convex and its image-side surface S5 being convex. The fourth lens E4 has positive optical power, with its object-side surface S6 being convex and its image-side surface S7 being convex. The fifth lens E5 has negative optical power, with its object-side surface S9 being concave and its image-side surface S10 being concave. The sixth lens E6 has positive optical power, with its object-side surface S10 being convex and its image-side surface S11 being convex. The seventh lens E7 has positive optical power, with its object-side surface S12 being convex and its image-side surface S13 being concave. The filter E8 has an object-side surface S14 and an image-side surface S15. Light from the object passes sequentially through surfaces S1 to S15 and is finally imaged onto the imaging surface S16.

[0079] Table 3 shows the surface type, radius of curvature, thickness, and material of each lens in the optical imaging lens of Example 2, wherein the units for radius of curvature and thickness are millimeters (mm).

[0080] Table 3

[0081]

[0082] In Table 4, the object-side surface and image-side surface of either the fourth lens E4 or the seventh lens E7 are aspherical. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formulas:

[0083]

[0084] Where x is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, h is the distance from the corresponding point on the aspherical surface to the optical axis, c is the curvature of the vertex of the aspherical surface, k is the conic coefficient, and Ai is the coefficient corresponding to the i-th higher-order term in the aspherical surface shape formula. Table 4 gives the conic coefficients and higher-order coefficients A4, A6, A8, A10, and A12 of each aspherical surface that can be used in the second embodiment.

[0085] Table 4

[0086]

[0087] Figure 5 The astigmatism and distortion curves of the optical imaging lens of Example 2 are shown. Astigmatism represents the meridional image plane curvature and the sagittal image plane curvature; distortion represents the distortion magnitude corresponding to different image heights.

[0088] Figure 6 The chromatic aberration curve of the optical imaging lens of Embodiment 2 is shown, which represents the chromatic aberration shift at different wavelengths.

[0089] The optical imaging lens given in Example 2 can achieve good imaging quality.

[0090] Example 3

[0091] The following is for reference Figures 7 to 9 Describes an optical imaging lens according to Embodiment 3 of this application. Figure 7 A schematic diagram of the structure of an optical imaging lens according to Embodiment 3 of this application is shown.

[0092] like Figure 7 As shown, the optical imaging lens according to an exemplary embodiment of this application includes, in sequence along the optical axis from the object side to the image side: 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.

[0093] The first lens E1 has negative optical power, with its object-side surface S1 being convex and its image-side surface S2 being concave. The second lens E2 has negative optical power, with its object-side surface S3 being concave and its image-side surface S4 being concave. The third lens E3 has positive optical power, with its object-side surface S4 being convex and its image-side surface S5 being convex. The fourth lens E4 has positive optical power, with its object-side surface S6 being convex and its image-side surface S7 being convex. The fifth lens E5 has positive optical power, with its object-side surface S9 being convex and its image-side surface S10 being convex. The sixth lens E6 has negative optical power, with its object-side surface S10 being concave and its image-side surface S11 being concave. The seventh lens E7 has positive optical power, with its object-side surface S12 being convex and its image-side surface S13 being convex. The filter E8 has an object-side surface S14 and an image-side surface S15. Light from the object passes sequentially through surfaces S1 to S15 and is finally imaged onto the imaging surface S16.

[0094] Table 5 shows the surface type, radius of curvature, thickness, and material of each lens in the optical imaging lens of Example 3, wherein the units for radius of curvature and thickness are millimeters (mm).

[0095] Table 5

[0096]

[0097] In Table 6, the object-side surface and image-side surface of either the fourth lens E4 or the seventh lens E7 are aspherical. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formulas:

[0098]

[0099] Where x is the distance from the corresponding point on the aspherical surface to the plane tangent to the vertex of the surface, h is the distance from the corresponding point on the aspherical surface to the optical axis, c is the curvature of the vertex of the aspherical surface, k is the conic coefficient, and Ai is the coefficient corresponding to the i-th higher-order term in the aspherical surface shape formula. Table 6 gives the conic coefficients and higher-order coefficients A4, A6, A8, A10, and A12 that can be used for each aspherical surface in the third embodiment.

[0100] Table 6

[0101]

[0102] Figure 8 The astigmatism and distortion curves of the optical imaging lens of Example 3 are shown. Astigmatism represents the meridional image plane curvature and the sagittal image plane curvature; distortion represents the distortion magnitude corresponding to different image heights.

[0103] Figure 9 The chromatic aberration curve of the optical imaging lens of Example 3 is shown, which represents the chromatic aberration shift at different wavelengths.

[0104] The optical imaging lens given in Example 3 can achieve good imaging quality.

[0105] A camera module includes at least an optical lens, in which the aforementioned vehicle-mounted forward-looking optical system is installed. The vehicle-mounted forward-looking optical system of the present invention has the advantages of low distortion, wide angle, and high resolution. At the same time, the wide angle can increase the amount of light entering the optical system and achieve higher imaging quality.

[0106] The above description provides one or more embodiments in conjunction with specific content, and does not imply that the specific implementation of the present invention is limited to these descriptions. Any methods or structures that are similar to or identical to those of the present invention, or any technical deductions or substitutions made based on the concept of the present invention, should be considered within the scope of protection of the present invention.

Claims

1. A low-distortion wide-angle, high-resolution vehicle-mounted forward-looking optical system, comprising, sequentially from the object plane to the image plane along the optical axis, a first lens, a second lens, a third lens, a fourth lens, an aperture stop, a fifth lens, a sixth lens, and a seventh lens, characterized in that: The object plane of the first lens is concave with a radius of curvature of -500mm, and the image plane is concave with a radius of curvature of 5.296mm. It has a negative optical power, a thickness of 2.337mm, a refractive index of 1.88, and a distance of 3.077mm between the first and second lenses. The object plane of the second lens is concave with a radius of curvature of -13.706 mm, and the image plane is concave with a radius of curvature of 17.382 mm. Its optical power is negative, its thickness is 2.454 mm, its refractive index is 1.70, and the distance between the second lens and the third lens is 0 mm. The object plane of the third lens is convex with a radius of curvature of 17.382 mm, and the image plane is convex with a radius of curvature of -12.184 mm. It has positive optical power, a thickness of 5.216 mm, a refractive index of 1.88, and the distance between the third lens and the fourth lens is 1.223 mm. The fourth lens has a convex object plane with a radius of curvature of 8.634 mm and a convex image plane with a radius of curvature of -11.223 mm. It has a positive optical power, a thickness of 3.906 mm, a refractive index of 1.60, and a distance of 0.214 mm from the fourth lens to the aperture stop. The fifth lens has a concave object plane with a radius of curvature of -27.15 mm and a concave image plane with a radius of curvature of 4.24 mm. It has a negative optical power, a thickness of 0.823 mm, a refractive index of 1.75, a distance of 2.254 mm from the aperture stop to the fifth lens, and a distance of 0 mm from the fifth lens to the sixth lens. The object plane side of the sixth lens is convex with a radius of curvature of 4.24 mm, and the image plane side is convex with a radius of curvature of -7.863 mm. It has a positive optical power, a thickness of 3.653 mm, a refractive index of 1.60, and a distance of 0.137 mm between the sixth and seventh lenses. The seventh lens has a convex object plane with a radius of curvature of 15.588 mm and a concave image plane with a radius of curvature of 26.334 mm. It has a positive optical power, a thickness of 1.274 mm, and a refractive index of 1.

77. The optical system satisfies the following relationship: 0.42 < f / TTL*ImagH < 0.65; Where f is the effective focal length of the optical system, TTL is the on-axis distance from the object side of the first lens to the imaging plane, and ImagH is half the diagonal length of the effective pixel area on the imaging plane.

2. The low-distortion wide-angle high-resolution vehicle-mounted forward-looking optical system according to claim 1, characterized in that: The first, second, third, fifth, and sixth lenses are spherical lenses, while the fourth and seventh lenses are aspherical glass lenses.

3. A camera module, comprising at least an optical lens, characterized in that: The optical lens is equipped with the low-distortion wide-angle high-resolution vehicle-mounted forward-looking optical system as described in any one of claims 1-2.

Images