A vehicle-mounted front-view optical lens

Abstract

The present invention provides a vehicle-mounted front-view optical lens, which has the characteristics of high resolution, large aperture, and large field of view, and meets the requirements of the automobile automatic driving system. 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 in sequence from the object side to the image side along the optical axis; a color filter, a protective glass, and an IMA are arranged in sequence behind the image side of the seventh lens; the first lens has a negative optical focal length, and its object side surface is convex, and its image side surface is concave; the second lens has a negative optical focal length, and its object side surface is concave, and its image side surface is convex; the third lens has a positive optical focal length, and its object side surface is convex, and its image side surface is convex; the fourth lens has a positive optical focal length, and its object side surface is convex, and its image side surface is convex; the fifth lens has a positive optical focal length, and its object side surface is convex, and its image side surface is convex.

Description

Technical Field

[0001] The invention relates to the technical field of lens structures, and in particular to a vehicle-mounted forward-looking optical lens. Background Art

[0002] With the development of automobile autonomous driving technology, the technical requirements of automobile autonomous driving systems for on-board cameras are getting higher and higher. Among them, the front-view vehicle lens is an important part of the automobile autonomous driving system. The front-view vehicle lens is mainly used to collect road condition information in front of the car to avoid traffic accidents. The image resolution captured by the existing front-view camera lens is low, the depth of field range is small, and it cannot capture the details of distant objects while ensuring the large field of view requirement. It is impossible to complete real-time and accurate monitoring of the vehicle's surrounding environment, and there is a certain driving risk. Summary of the invention

[0003] In view of the above problems, the present invention provides a vehicle-mounted forward-looking optical lens, which has the characteristics of high resolution, large aperture, and large field of view, and meets the requirements of the vehicle's automatic driving system.

[0004] A vehicle-mounted front-view optical lens, characterized in that it comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens arranged in sequence from the object side to the image side along the optical axis;

[0005] A color filter, a protective glass and an IMA are sequentially arranged behind the image side of the seventh lens;

[0006] The first lens has negative optical power, its object side surface is convex, and its image side surface is concave;

[0007] The second lens has negative optical power, its object side surface is concave, and its image side surface is convex;

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

[0009] The fourth lens has positive refractive power, and its object side surface is convex, and its image side surface is convex;

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

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

[0012] The seventh lens has positive refractive power, its object side surface is convex, and its image side surface is concave;

[0013] The first lens, the second lens and the seventh lens are all glass aspherical lenses, and the third lens, the fourth lens, the fifth lens and the sixth lens are glass spherical lenses.

[0014] It is further characterized by:

[0015] The first lens satisfies Nd1>1.8, Vd1<45, wherein Nd1 refers to the refractive index of the first lens, and Vd1 refers to the Abbe number of the first lens;

[0016] The second lens satisfies Nd2>1.85, Vd2<45, wherein Nd2 refers to the refractive index of the second lens, and Vd2 refers to the Abbe number of the second lens;

[0017] The third lens satisfies Nd3>1.75, Vd3<45, wherein Nd3 refers to the refractive index of the third lens, and Vd3 refers to the Abbe number of the third lens;

[0018] The fourth lens satisfies Nd4<1.65, Vd4>55, wherein Nd4 refers to the refractive index of the fourth lens, and Vd4 refers to the Abbe number of the fourth lens; the fourth lens satisfies dn / dt4<-3×10 -6 ℃, where dn / dt4 refers to the refractive index temperature coefficient of the fourth lens;

[0019] The seventh lens satisfies Nd7>1.75, Vd7<50, wherein Nd7 refers to the refractive index of the seventh lens, and Vd7 refers to the Abbe number of the seventh lens;

[0020] Preferably, the fifth lens and the sixth lens form a cemented lens; in this case, the difference △Nd of the Abbe numbers of the two fifth lenses and the sixth lens satisfies: 35<|△Nd|<45;

[0021] It also includes an aperture, which is located between the third lens and the fourth lens;

[0022] The optical lens composed thereof satisfies the following parameter condition, BFL / TTL≤0.2, wherein BFL is the distance from the center of the image side surface of the last lens of the optical lens to the imaging surface of the optical lens on the optical axis; and TTL is the distance from the center of the object side surface of the first lens to the imaging surface of the optical lens on the optical axis;

[0023] The optical lens composed thereof satisfies the following parameter conditions: FOV / h / D≤4.9, wherein FOV is the maximum field of view of the optical lens; D is the maximum aperture of the object side of the first lens corresponding to the maximum field of view of the optical lens; and h is the image height corresponding to the maximum field of view of the optical lens;

[0024] The optical lens composed thereof satisfies the following parameter conditions: FOV×F / h≥58, wherein FOV represents the maximum field of view angle of the optical lens; F represents the overall focal length value of the optical system; h represents the image height corresponding to the maximum field of view angle of the optical lens;

[0025] The optical lens composed thereof satisfies the following parameter condition: TTL / F≤8, wherein TTL is the distance from the center of the object side surface of the first lens to the imaging surface of the optical lens on the optical axis;

[0026] The optical lens composed thereof satisfies the following parameter conditions: -2≤f1 / F≤-1.5, -10≤f2 / F≤-5.5, 2.5≤f3 / F≤3.5, 2.5≤f4 / F≤3, 1.3≤f5 / F≤2, -1.5≤f6 / F≤-1, 3≤f7 / F≤6, wherein f1, f2, f3, f4, f5, f6, f7 are respectively the focal lengths of the first lens to the seventh lens, and F is the overall focal length value of the optical system.

[0027] After adopting the present invention, 4 glass spherical lenses plus 3 glass aspherical lenses are combined to form a vehicle-mounted front-view optical lens, which has a simple structure and a small volume. The image plane drift is small in the range of -40° to 125°, and clear imaging can be achieved, meeting the 8-megapixel imaging requirement. The aperture is large and the shooting field of view range is 120; it has the characteristics of high resolution, large aperture, and large field of view, meeting the needs of the automobile automatic driving system. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a lens structure combination diagram of an embodiment of the present invention (the object side is at the leftmost position, and the image side is at the rightmost position);

[0029] Figure 2 This is an MTF curve diagram of an embodiment of the present invention;

[0030] Figure 3 This is a defocus curve diagram of an embodiment of the present invention at 25°;

[0031] Figure 4 This is a defocus curve diagram of an embodiment of the present invention at -40°;

[0032] Figure 5 This is a defocus curve diagram of an embodiment of the present invention at 125°;

[0033] The names corresponding to the serial numbers in the figure are as follows:

[0034] First lens L1, second lens L2, third lens L3, fourth lens L4, fifth lens L5, sixth lens L6, seventh lens L7, aperture stop STOP, color filter IR, and protective glass CG. DETAILED DESCRIPTION

[0035] A vehicle-mounted front-view optical lens, see Figure 1-Figure 5: It includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6 and a seventh lens L7 which are arranged in sequence from the object side to the image side along the optical axis;

[0036] A color filter IR, a protective glass CG and an IMA are arranged in sequence behind the image side of the seventh lens L7;

[0037] The first lens L1 has negative power, its object side surface is convex, its image side surface is concave, and the first lens L1 satisfies Nd1>1.8, Vd1<45, where Nd1 refers to the refractive index of the first lens L1, and Vd1 refers to the Abbe number of the first lens L1;

[0038] The second lens L2 has negative power, its object side surface is concave, its image side surface is convex, and the second lens L2 satisfies Nd2>1.85, Vd2<45, where Nd2 refers to the refractive index of the second lens L2, and Vd2 refers to the Abbe number of the second lens L2;

[0039] The third lens L3 has positive refractive power, its object side surface is convex, its image side surface is convex, and the third lens L3 satisfies Nd3>1.75, Vd3<45, where Nd3 refers to the refractive index of the third lens L3, and Vd3 refers to the Abbe number of the third lens L3;

[0040] The fourth lens L4 has positive power, its object side surface is convex, its image side surface is convex, the fourth lens L4 satisfies Nd4<1.65, Vd4>55, wherein Nd4 refers to the refractive index of the fourth lens L4, and Vd4 refers to the Abbe number of the fourth lens L4; the fourth lens L4 satisfies dn / dt4<-3X10 -6 ℃, where dn / dt4 refers to the refractive index temperature coefficient of the fourth lens L4;

[0041] The fifth lens L5 has positive refractive power, and its object-side surface is convex and its image-side surface is convex;

[0042] The sixth lens L6 has negative refractive power, and its object-side surface is concave and its image-side surface is concave;

[0043] The seventh lens L7 has positive power, its object-side surface is convex, its image-side surface is concave, and the seventh lens L7 satisfies Nd7>1.75, Vd7<50, where Nd7 refers to the refractive index of the seventh lens L7, and Vd7 refers to the Abbe number of the seventh lens L7;

[0044] The first lens L1, the second lens L2 and the seventh lens L7 are all glass aspherical lenses, and the third lens L3, the fourth lens L4, the fifth lens L5 and the sixth lens L6 are glass spherical lenses.

[0045] The optical lens composed thereof satisfies the following parameter conditions, BFL / TTL≤0.2, wherein BFL is the distance from the center of the image side surface of the last lens of the optical lens to the imaging surface of the optical lens on the optical axis; and TTL is the distance from the center of the object side surface of the first lens L1 to the imaging surface of the optical lens on the optical axis;

[0046] The optical lens composed thereof satisfies the following parameter conditions: FOV / h / D≤4.9, wherein FOV is the maximum field angle of the optical lens; D is the maximum aperture of the object side of the first lens L1 corresponding to the maximum field angle of the optical lens; and h is the image height corresponding to the maximum field angle of the optical lens;

[0047] The optical lens composed thereof satisfies the following parameter conditions: FOV×F / h≥58, wherein FOV represents the maximum field of view angle of the optical lens; F represents the overall focal length value of the optical system; h represents the image height corresponding to the maximum field of view angle of the optical lens;

[0048] The optical lens composed thereof satisfies the following parameter conditions: TTL / F≤8, wherein TTL is the distance from the center of the object side surface of the first lens L1 to the imaging surface of the optical lens on the optical axis;

[0049] The optical lens composed thereof satisfies the following parameter conditions: -2≤f1 / F≤-1.5, -10≤f2 / F≤-5.5, 2.5≤f3 / F≤3.5, 2.5≤f4 / F≤3, 1.3≤f5 / F≤2, -1.5≤f6 / F≤-1, 3≤f7 / F≤6, wherein f1, f2, f3, f4, f5, f6, and f7 are respectively the focal lengths of the first lens L1 to the seventh lens L7, and F is the overall focal length of the optical system.

[0050] In a specific embodiment, the fifth lens L5 and the sixth lens L6 form a cemented lens; at this time, the difference △Nd of the Abbe numbers of the two fifth lenses L5 and the sixth lens L6 satisfies: 35<|△Nd|<45; it also includes an aperture stop, and the aperture stop STOP is located between the third lens L3 and the fourth lens L4;

[0051] The optical parameters are shown in Table 1:

[0052] Table 1

[0053]

[0054] In Table 1, when the radius of curvature of the aperture, IR filter, and protective glass surface is Infinity, it means that the surface is a plane.

[0055] The parameter conditions satisfied by the optical lens are shown in Table 2:

[0056] Table 2

[0057] project TTL / F FOV×F / h FOV / h / D BFL / TTL scope 7.95 60 4.8 0.14

[0058] The first lens L1, the second lens L2 and the seventh lens L7 are aspherical lenses, and the aspherical surface shapes of each lens are described as follows:

[0059]

[0060] Among them, Z(h) is the distance vector height from the vertex of the aspherical surface when the aspherical surface is at a height of h along the optical axis, c=1 / r, r represents the radius of curvature of the aspherical mirror surface, k is the cone coefficient conic, and A, B, C, D, and E are the coefficients of the high-order terms of the aspherical surface.

[0061] The surface parameters of each aspheric surface are shown in Table 3:

[0062] Table 3

[0063]

[0064] The vehicle-mounted front-view optical lens is formed by combining 4 glass spherical lenses and 3 glass aspherical lenses. It has a simple structure and small size. The image plane drift is small in the range of -40° to 125°, which can achieve clear imaging and meet the 8-megapixel imaging requirements. It has a large aperture and a shooting field of view of 120. It has the characteristics of high resolution, large aperture, and large field of view, which meet the needs of automobile automatic driving systems.

[0065] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0066] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A vehicle-mounted front-view 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 in sequence from the object side to the image side along the optical axis; A color filter, a protective glass and an IMA are sequentially arranged behind the image side of the seventh lens; The first lens has negative optical power, its object side surface is convex, and its image side surface is concave; The second lens has negative optical power, its object side surface is concave, and its image side surface is convex; The third lens has positive refractive power, and its object side surface is convex, and its image side surface is convex; The fourth lens has positive refractive power, and its object side surface is convex, and its image side surface is convex; The fifth lens has positive refractive power, and its object side surface is convex, and its image side surface is convex; The sixth lens has negative optical power, and its object side surface is concave, and its image side surface is concave; The seventh lens has positive refractive power, its object side surface is convex, and its image side surface is concave; The first lens, the second lens and the seventh lens are all glass aspherical lenses, and the third lens, the fourth lens, the fifth lens and the sixth lens are glass spherical lenses; The first lens satisfies Nd1>1.8, Vd1<45, wherein Nd1 refers to the refractive index of the first lens, and Vd1 refers to the Abbe number of the first lens; The second lens satisfies Nd2>1.85, Vd2<45, wherein Nd2 refers to the refractive index of the second lens, and Vd2 refers to the Abbe number of the second lens; The third lens satisfies Nd3>1.75, Vd3<45, wherein Nd3 refers to the refractive index of the third lens, and Vd3 refers to the Abbe number of the third lens; The fourth lens satisfies Nd4<1.65, Vd4>55, wherein Nd4 refers to the refractive index of the fourth lens, and Vd4 refers to the Abbe number of the fourth lens; the fourth lens satisfies dn / dt4<-3X10 -6 ℃, where dn / dt4 refers to the refractive index temperature coefficient of the fourth lens; The seventh lens satisfies Nd7>1.75, Vd7<50, wherein Nd7 refers to the refractive index of the seventh lens, and Vd7 refers to the Abbe number of the seventh lens; The optical lens composed thereof satisfies the following parameter condition, BFL / TTL≤0.2, wherein BFL is the distance from the center of the image side surface of the last lens of the optical lens to the imaging surface of the optical lens on the optical axis; and TTL is the distance from the center of the object side surface of the first lens to the imaging surface of the optical lens on the optical axis; The optical lens composed thereof satisfies the following parameter conditions: FOV / h / D≤4.9, wherein FOV is the maximum field of view of the optical lens; D is the maximum aperture of the object side of the first lens corresponding to the maximum field of view of the optical lens; and h is the image height corresponding to the maximum field of view of the optical lens; The optical lens composed thereof satisfies the following parameter conditions: FOV×F / h≥58, wherein FOV represents the maximum field of view angle of the optical lens; F represents the overall focal length value of the optical system; h represents the image height corresponding to the maximum field of view angle of the optical lens; The optical lens composed of the above-mentioned components satisfies the following parameter condition: TTL / F≤8, wherein TTL is the distance from the center of the object side surface of the first lens to the imaging surface of the optical lens on the optical axis.

2. The vehicle-mounted forward-looking optical lens according to claim 1, characterized in that: The fifth lens and the sixth lens form a cemented lens.

3. The vehicle-mounted forward-looking optical lens according to claim 2, characterized in that: The Abbe number difference ΔNd between the fifth lens and the sixth lens satisfies: 35<|ΔNd|<45.

4. The vehicle-mounted front-view optical lens according to claim 1, characterized in that: It also includes an aperture stop, which is located between the third lens and the fourth lens.

5. The vehicle-mounted front-view optical lens according to claim 1, characterized in that: The optical lens composed thereof satisfies the following parameter conditions: -2≤f1 / F≤-1.5, -10≤f2 / F≤-5.5, 2.5≤f3 / F≤3.5, 2.5≤f4 / F≤3, 1.3≤f5 / F≤2, -1.5≤f6 / F≤-1, 3≤f7 / F≤6, wherein f1, f2, f3, f4, f5, f6, f7 are respectively the focal lengths of the first lens to the seventh lens, and F is the overall focal length value of the optical system.

Images