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

Abstract

The present invention discloses a long-focus vehicle-mounted forward-looking optical system and a camera module used therein. The system is mainly composed of six lenses, with a reasonable number of lenses and a simple structure. By adopting a full-spherical lens configuration and rationally distributing the lens optical power, the system has the advantages of both long focus and miniaturization, full-spherical lenses and low cost, and high angular resolution, making the miniaturized vehicle-mounted forward-looking lens more competitive in the market.

Description

Technical Field

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

[0002] With the increasing application and popularity of vehicle-assisted driving systems, optical systems or modules in the automotive field have also been widely used. Automotive forward-view optical lenses play an important role in collision warning, lane departure warning, pedestrian detection and warning, and other fields. To meet these functions, the system needs to have increasingly high recognition of distant objects ahead. Specifically, this requires the lens to have high-definition resolution, large angular resolution, and a long focal length. To achieve high resolution, most lenses on the market use aspherical surfaces, which increases the cost of the lens. At the same time, the long focal length increases the overall length of the lens, which is not conducive to lens miniaturization. Summary of the Invention

[0003] In order to overcome the problems of long total lens length and high cost commonly found in existing optical systems or camera modules used for vehicle-mounted surround-view lenses, the present application provides a long-focus vehicle-mounted forward-looking optical system, which has the advantages of long focus and miniaturization, full-spherical lenses and low cost, and high angular resolution.

[0004] A long-focus vehicle-mounted forward-looking optical system, which is composed of a first lens, a second lens, a third lens, an aperture, a fourth lens, a fifth lens, and a sixth lens in sequence from the object plane to the image plane along the optical axis;

[0005] The object side of the first lens is concave, the image side is concave, and its optical power is negative;

[0006] The object side of the second lens is convex, the image side is convex, and its optical power is positive;

[0007] The object side of the third lens is concave, the image side is convex, and its optical power is positive;

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

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

[0010] The object side of the sixth lens is convex, the image side is concave, and its optical power is positive.

[0011] The telephoto vehicle-mounted forward-looking optical system as described above satisfies TTL / EFL≤3.5, wherein TTL is the distance between the vertex on the object side of the first lens of the optical system and the image plane, and EFL is the effective focal length of the optical system.

[0012] The long - focal - length vehicle - mounted front - view optical system as described above, each lens of the optical system satisfies the following conditions:

[0013] (1) - 15mm < f1 < - 3mm;

[0014] (2) 4mm < f2 < 20mm;

[0015] (3) 5mm < f3 < 50mm;

[0016] (4) 3mm < f4 < 20mm;

[0017] (5) - 20mm < f5 < - 4mm;

[0018] (6) 10mm < f6 < 100mm;

[0019] 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, and f6 is the focal length of the sixth lens.

[0020] The long - focal - length vehicle - mounted front - view optical system as described above, each lens of the optical system satisfies the following conditions:

[0021] (1) - 2.5 < f1 / f < - 0.3;

[0022] (2) 0.4 < f2 / f < 3.0;

[0023] (3) 0.5 < f3 / f < 8.0;

[0024] (4) 0.3 < f4 / f < 3.0;

[0025] (5) - 4.0 < f5 / f < - 0.5;

[0026] (6) 1.5 < f6 / f < 15.0;

[0027] Among them, 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, and f6 is the focal length of the sixth lens.

[0028] The long - focal - length vehicle - mounted front - view optical system as described above, the optical system satisfies the following conditions: The refractive index Nd1 and Abbe number Vd1 of the material of the first lens satisfy: 1.49 < Nd1 < 1.75, 50 < Vd1 < 70.5; and / or

[0029] The refractive index Nd2 and Abbe number Vd2 of the material of the second lens satisfy: 1.7 < Nd2 < 2.1, 25 < Vd2 < 55.

[0030] For the long - focal - length vehicle - mounted forward - looking optical system as described above, the optical system satisfies the following conditions: The refractive index Nd3 and Abbe number Vd3 of the material of the third lens satisfy: 1.49 < Nd1 < 1.75, 50 < Vd1 < 82; and / or

[0031] The refractive index Nd4 and Abbe number Vd4 of the material of the fourth lens satisfy: 1.49 < Nd4 < 1.62, 63 < Vd4 < 82.

[0032] For the long - focal - length vehicle - mounted forward - looking optical system as described above, the optical system satisfies the following conditions: The refractive index Nd5 and Abbe number Vd5 of the material of the fifth lens satisfy: 1.65 < Nd5 < 1.95, 17.5 < Vd5 < 35; and / or

[0033] The refractive index Nd6 and Abbe number Vd6 of the material of the sixth lens satisfy: 1.7 < Nd2 < 2.1, 25 < Vd2 < 55.

[0034] For the long - focal - length vehicle - mounted forward - looking optical system as described above, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are all spherical lenses.

[0035] For the long - focal - length vehicle - mounted forward - looking optical system as described above, the fourth lens and the fifth lens are mutually cemented to form a combined lens.

[0036] On the other hand, an embodiment of the present application further provides a vehicle - mounted forward - looking camera module.

[0037] A camera module at least includes an optical lens, and the above - mentioned long - focal - length vehicle - mounted forward - looking optical system is installed in the optical lens.

[0038] Compared with the prior art, the beneficial effects of the present application are as follows:

[0039] The optical system and the camera module of the embodiments of the present invention are mainly composed of 6 lenses, with a reasonable number of lenses and a simple structure. By adopting a global - spherical lens configuration and reasonably distributing the lens optical power, they have the advantages of兼顾长焦和小型化, global - spherical lenses兼顾低成本, and at the same time having high angular resolution, making the miniaturized vehicle - mounted forward - looking lens more competitive in the market. Brief Description of the Drawings

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments.

[0041] Figure 1Schematic diagram of the structure of the optical system or camera module according to an embodiment of the present application;

[0042] Figure 2 is an astigmatism and distortion curve diagram of the optical system or camera module according to an embodiment of the present application;

[0043] Figure 3 It is an MTF curve diagram of the optical system or camera module of the embodiment of the present application. DETAILED DESCRIPTION

[0044] like Figure 1-3 As shown, the present application provides a telephoto vehicle-mounted forward-looking optical system, which is composed of a first lens L1, a second lens L2, a third lens L3, an aperture STO, a fourth lens L4, a fifth lens L5, a sixth lens L6 and a filter L7 in sequence along the optical axis from the object plane to the image plane.

[0045] The object side and image side of the first lens L1 are concave, and its optical power is negative;

[0046] The object side and image side of the second lens L2 are convex, and its optical power is positive;

[0047] The object side of the third lens L3 is concave, the image side is convex, and its optical power is positive;

[0048] The fourth lens L4 has a convex object side surface and a convex image side surface, and has positive optical power;

[0049] The fifth lens L5 has a concave object side surface and a convex image side surface, and has negative optical power;

[0050] The object side of the sixth lens L6 is convex, the image side is concave, and its optical power is positive.

[0051] The optical system of the embodiment of the present invention is mainly composed of six lenses, with a reasonable number of lenses and a simple structure. By adopting a full-spherical lens configuration and rationally distributing the lens optical power, it has the advantages of long focus and miniaturization, full-spherical lenses and low cost, and high angular resolution. This makes the miniaturized automotive front-view lens more competitive in the market.

[0052] Furthermore, as a preferred embodiment of the present invention but not a limitation, the optical system satisfies TTL / EFL≤3.5, where TTL is the distance between the object-side vertex of the first lens L1 of the optical system and the image plane, and EFL is the effective focal length of the optical system. This design can reduce the total optical length and effectively miniaturize the lens.

[0053] Furthermore, as a preferred embodiment of the present invention but not limiting, each lens of the optical system satisfies the following conditions:

[0054] (1) - 15 mm < f1 < - 3 mm;

[0055] (2) 4 mm < f2 < 20 mm;

[0056] (3) 5 mm < f3 < 50 mm;

[0057] (4) 3 mm < f4 < 20 mm;

[0058] (5) - 20 mm < f5 < - 4 mm;

[0059] (6) 10 mm < f6 < 100 mm;

[0060] Among them, f1 is the focal length of the first lens L1, f2 is the focal length of the second lens L2, f3 is the focal length of the third lens L3, f4 is the focal length of the fourth lens L4, f5 is the focal length of the fifth lens L5, and f6 is the focal length of the sixth lens L6. By reasonably distributing the focal lengths of each lens, it has the advantages of both long focal length and miniaturization, and at the same time has high angular resolution, making the miniaturized vehicle front view lens more competitive in the market.

[0061] Furthermore, as a preferred implementation manner rather than a limitation of the present invention, each lens of the optical system satisfies the following conditions:

[0062] (1) - 2.5 < f1 / f < - 0.3. By restricting the ratio of the focal length of the first lens L1 to the effective focal length of the optical imaging system within a reasonable range, the distortion of the system is controlled, so that the imaging center has higher angular resolution;

[0063] (2) 0.4 < f2 / f < 3.0. By restricting the ratio of the focal length of the second lens L2 to the effective focal length of the optical imaging system within a reasonable range, the spherical aberration of the system is finely adjusted and controlled, thereby effectively improving the imaging quality of the system;

[0064] (3) 0.5 < f3 / f < 8.0. By restricting the ratio of the focal length of the third lens L3 to the effective focal length of the optical imaging system within a reasonable range, the configured long - focal - length vehicle front view optical system has excellent temperature characteristics, thereby improving the imaging stability of the optical system at high and low temperatures and enhancing the imaging quality;

[0065] (4) 0.3 < f4 / f < 3.0. By restricting the ratio of the optical power of the fourth lens L4 to the effective focal length of the optical imaging system within a reasonable range, the configured long - focal - length vehicle front view optical system has excellent temperature characteristics, thereby improving the imaging stability of the optical system at high and low temperatures and enhancing the imaging quality;

[0066] (5) -4.0 < f5 / f < -0.5. By reasonably controlling the ratio range of the focal length of the fifth lens L5 to the effective focal length of the optical imaging system, the astigmatism and field curvature of the system are well corrected, effectively improving the imaging quality of the system.

[0067] (6) 1.5 < f6 / f < 15.0. By restricting the ratio of the focal length of the sixth lens L6 to the effective focal length of the optical imaging system within a reasonable range, the trend of light rays in the system is well controlled, effectively controlling the effective aperture of the lens, eliminating the aberration of the system, and correcting the astigmatism and field curvature of the system.

[0068] Among them, f is the focal length of the entire optical system, f1 is the focal length of the first lens L1, f2 is the focal length of the second lens L2, f3 is the focal length of the third lens L3, f4 is the focal length of the fourth lens L4, f5 is the focal length of the fifth lens L5, and f6 is the focal length of the sixth lens L6.

[0069] Furthermore, as a preferred embodiment rather than a limitation of the present invention, the optical system satisfies the following conditions: the refractive index Nd1 and Abbe number Vd1 of the material of the first lens L1 satisfy: 1.49 < Nd1 < 1.75, 50 < Vd1 < 70.5. This design can effectively reduce chromatic aberration, optimize the lens aberration, and thus effectively improve the imaging quality of the system.

[0070] Furthermore, as a preferred embodiment rather than a limitation of the present invention, the refractive index Nd2 and Abbe number Vd2 of the material of the second lens L2 satisfy: 1.7 < Nd2 < 2.1, 25 < Vd2 < 55. This design can effectively reduce chromatic aberration, optimize the lens aberration, and thus effectively improve the imaging quality of the system.

[0071] Furthermore, as a preferred embodiment rather than a limitation of the present invention, the optical system satisfies the following conditions: the refractive index Nd3 and Abbe number Vd3 of the material of the third lens L3 satisfy: 1.49 < Nd1 < 1.75, 50 < Vd1 < 82. This design can effectively reduce chromatic aberration, optimize the lens aberration, and thus effectively improve the imaging quality of the system.

[0072] Furthermore, as a preferred embodiment rather than a limitation of the present invention, the refractive index Nd4 and Abbe number Vd4 of the material of the fourth lens L4 satisfy: 1.49 < Nd4 < 1.62, 63 < Vd4 < 82. This design can effectively reduce chromatic aberration, optimize the lens aberration, and thus effectively improve the imaging quality of the system.

[0073] Further, as a preferred embodiment rather than a limitation of the present invention, the optical system satisfies the following conditions: the refractive index Nd5 and the Abbe number Vd5 of the material of the fifth lens L5 satisfy: 1.65 < Nd5 < 1.95, 17.5 < Vd5 < 35. This design can effectively reduce chromatic aberration, optimize lens aberration, and thus effectively improve the imaging quality of the system;

[0074] Further, as a preferred embodiment rather than a limitation of the present invention, the refractive index Nd6 and the Abbe number Vd6 of the material of the sixth lens L6 satisfy: 1.7 < Nd2 < 2.1, 25 < Vd2 < 55. This design can effectively reduce chromatic aberration, optimize lens aberration, and thus effectively improve the imaging quality of the system.

[0075] Further, as a preferred embodiment rather than a limitation of the present invention, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, and the sixth lens L6 are all spherical lenses. By adopting a global spherical lens configuration, it has the advantages of long focal length and miniaturization, global spherical lenses and low cost, and high angular resolution at the same time, making the miniaturized vehicle front view lens more competitive in the market.

[0076] Further, as a preferred embodiment rather than a limitation of the present invention, the fourth lens L4 and the fifth lens L5 are mutually cemented to form a combined lens, which is beneficial to lens miniaturization and has the advantage of high angular resolution at the same time, making the miniaturized vehicle front view lens more competitive in the market.

[0077] Specifically, as a preferred embodiment rather than a limitation of the present invention, as Figure 1-3 shown, in this embodiment, the focal length f1 of the first lens L1 = -4.2 mm, the focal length f2 of the second lens L2 = 5.6 mm, the focal length f3 of the third lens L3 = 47.1 mm, the focal length f4 of the fourth lens L4 = 8.6 mm, the focal length f5 of the fifth lens L5 = -12.5 mm, the focal length f6 of the sixth lens L6 = 18.1 mm. The curvature radius, thickness and material parameters of each lens are shown in Table 1:

[0078] Table 1: Basic parameters of the optical system of the embodiment

[0079] surface Curvature radius R(mm) Thickness D(mm) Refractive index Nd Dispersion value Vd S1 -6.03 1.25 1.70 55.5 S2 6.03 0.39 S3 8.95 2.70 1.91 35.3 S4 -10.44 1.50 S5 5.70 1.50 1.50 81.6 S6 -5.00 0.10 STO Infinity 0.40 S7 22.00 2.25 1.57 71.3 S8 -6.10 0.50 1.92 18.9 S9 -13.02 5.21 S10 5.85 2.00 1.83 42.7 S11 8.01 4.00 S12 INFINITY 0.70 1.52 64.2 S13 INFINITY 0.54 S14 INFINITY -

[0080] In Table 1 above, along the optical axis from the object plane to the image plane, S1 and S2 correspond to the two surfaces of the first lens L1; S3 and S4 correspond to the two surfaces of the second lens L2; ​​S5 and S6 correspond to the two surfaces of the third lens L3; STO corresponds to the position of the aperture stop STO of the optical system; S7 and S8 correspond to the two surfaces of the fourth lens L4; S8 and S9 correspond to the two surfaces of the fifth lens L5; S10 and S11 correspond to the two surfaces of the sixth lens L6; S12 and S13 correspond to the two surfaces of the infrared cutoff filter and / or protective glass; S14 corresponds to the sensor imaging surface.

[0081] Figure 1 The schematic diagram of the structure of the optical imaging lens of an embodiment of the present application is shown. The first lens L1 has negative focal power, and its object-side surface S1 is concave, and its image-side surface S2 is concave; the second lens L2 has positive focal power, and its object-side surface S3 is convex, and its image-side surface S4 is convex; the third lens L3 has positive focal power, and its object-side surface S5 is concave, and its image-side surface S6 is convex; the fourth lens L4 has positive focal power, and its object-side surface S7 is convex, and its image-side surface S8 is convex; the fifth lens L5 has negative focal power, and its object-side surface S8 is concave, and its image-side surface S9 is convex. The sixth lens L6 has positive focal power, and its object-side surface S10 is convex, and its image-side surface S11 is concave. The filter L7 has an object-side surface S12 and an image-side surface S13. The light from the object passes through each surface S1 to S13 in sequence and is finally imaged on the imaging surface S14;

[0082] Figure 2 The astigmatism and distortion curves of the optical imaging lens of the embodiment are shown. Astigmatism represents meridional image curvature and sagittal image curvature, and distortion represents the corresponding distortion magnitude values ​​at different field angles.

[0083] Figure 3 The MTF curve of the optical imaging lens of the embodiment is shown, which represents the MTF values ​​in the meridional and sagittal directions of different fields of view at different spatial frequencies;

[0084] Depend on Figure 2 and Figure 3 It can be seen that the optical imaging system provided in the embodiment can achieve good imaging quality and has higher imaging quality.

[0085] A camera module includes at least an optical lens, in which the above-mentioned long-focus vehicle-mounted forward-looking optical system is installed. The application has a reasonable number of lenses and a simple structure. By adopting a full-spherical lens configuration and reasonably distributing the lens optical focal length, it has the advantages of long focus and miniaturization, full-spherical lenses and low cost, and high angular resolution, making the miniaturized vehicle-mounted forward-looking lens more competitive in the market.

[0086] 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 long - focal - length vehicle front - view optical system is composed of a first lens, a second lens, a third lens, an aperture stop, a fourth lens, a fifth lens, and a sixth lens in sequence along the optical axis from the object plane to the image plane. It is characterized in that: The object - side of the first lens is concave, the image - side is concave, and its optical power is negative; The object - side of the second lens is convex, the image - side is convex, and its optical power is positive; The object - side of the third lens is concave, the image - side is convex, and its optical power is positive; The object - side of the fourth lens is convex, the image - side is convex, and its optical power is positive; The object - side of the fifth lens is concave, the image - side is convex, and its optical power is negative; The object - side of the sixth lens is convex, the image - side is concave, and its optical power is positive; The first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are all spherical lenses; The lenses of this optical system satisfy the following conditions: (1) - 15mm < f1 < - 3mm; (2) 4mm < f2 < 20mm; (3) 5mm < f3 < 50mm; (4) 3mm < f4 < 20mm; (5) - 20mm < f5 < - 4mm; (6) 10mm < f6 < 100mm; 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, and f6 is the focal length of the sixth lens.

2. The long-focus vehicle-mounted forward-looking optical system according to claim 1, characterized in that: This optical system satisfies TTL / EFL ≤ 3.5, where TTL is the distance from the vertex of the object - side of the first lens of the optical system to the image plane, and EFL is the effective focal length of the optical system.

3. The long-focus vehicle-mounted forward-looking optical system according to claim 1, characterized in that: The lenses of this optical system satisfy the following conditions: (1) - 2.5 < f1 / f < - 0.3; (2) 0.4 < f2 / f < 3.0; (3) 0.5 < f3 / f < 8.0; (4) 0.3 < f4 / f < 3.0; (5) - 4.0 < f5 / f < - 0.5; (6) 1.5 < f6 / f < 15.0; Among them, 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, and f6 is the focal length of the sixth lens.

4. The long-focus vehicle-mounted forward-looking optical system according to any one of claims 1 to 3, characterized in that: This optical system satisfies the following conditions: The refractive index Nd1 and Abbe number Vd1 of the material of the first lens satisfy: 1.49 < Nd1 < 1.75, 50 < Vd1 < 70.5; and / or The refractive index Nd2 and Abbe number Vd2 of the material of the second lens satisfy: 1.7 < Nd2 < 2.1, 25 < Vd2 < 55.

5. The long-focus vehicle-mounted forward-looking optical system according to any one of claims 1 to 3, characterized in that: This optical system satisfies the following conditions: The refractive index Nd3 and Abbe number Vd3 of the material of the third lens satisfy: 1.49 < Nd1 < 1.75, 50 < Vd1 < 82; and / or The refractive index Nd4 and Abbe number Vd4 of the material of the fourth lens satisfy: 1.49 < Nd4 < 1.62, 63 < Vd4 < 82.

6. The long-focus vehicle-mounted forward-looking optical system according to any one of claims 1 to 3, characterized in that: The optical system satisfies the following conditions: the refractive index Nd5 and the Abbe number Vd5 of the material of the fifth lens satisfy: 1.65 < Nd5 < 1.95, 17.5 < Vd5 < 35; and / or the refractive index Nd6 and the Abbe number Vd6 of the material of the sixth lens satisfy: 1.7 < Nd2 < 2.1, 25 < Vd2 < 55.

7. The long-focus vehicle-mounted forward-looking optical system according to any one of claims 1 to 3, characterized in that: It further includes a filter disposed between the sixth lens and the image plane.

8. The long-focus vehicle-mounted forward-looking optical system according to any one of claims 1 to 3, characterized in that: The fourth lens and the fifth lens are mutually cemented to form a combined lens.

9. A camera module, comprising at least an optical lens, characterized in that: A long-focus vehicle-mounted front-view optical system according to any one of claims 1-8 is installed inside the optical lens.

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