High-definition wide-viewing-angle automobile electronic mirror

Abstract

The application discloses a high-definition wide-viewing-angle automobile rearview mirror. The automobile rearview mirror comprises a first lens, a second lens, a third lens, a diaphragm, a fourth lens, a fifth lens, a sixth lens, a seventh lens, a parallel flat plate and an image plane IMA which are sequentially arranged along an optical axis from an object side to an image side; the first lens has negative optical power; the second lens has negative optical power; the third lens has positive optical power; the fourth lens has positive optical power; the fifth lens has positive optical power; the sixth lens has negative optical power; and the seventh lens has positive optical power. The application has simple overall structure, small volume, low cost, small temperature drift, meets the imaging requirement of high pixels and the requirement of wide viewing angle, and can correct image distortion to a certain extent.

Description

Technical Field

[0001] This invention relates to the field of optical lens technology, specifically to a high-definition, wide-angle automotive rearview mirror. Background Technology

[0002] In recent years, with the development of in-vehicle technology and autonomous driving technology, the technical requirements for in-vehicle cameras have become increasingly stringent, including those for front-view, side-view, and rear-view cameras, as well as for cruise control and dashcams. Among these, rear-view cameras are a crucial component of advanced driver assistance systems (ADAS), allowing drivers to visually see obstacles behind the vehicle and avoid accidents. However, traditional rearview mirrors often suffer from low image clarity and cannot simultaneously meet the requirements of high definition and a wide viewing angle. This prevents drivers from accurately assessing their surroundings and making timely warnings or evasive maneuvers. Furthermore, rearview mirrors often experience significant degradation in clarity under extreme temperatures, exhibiting large temperature drift, insufficient peripheral brightness, and low relative illumination, posing a driving risk.

[0003] With the development of the automotive industry and the increasing maturity of video and surveillance technologies in China, lens imaging technology has become an indispensable part of various industries. In recent years, the domestic market for dashcams, panoramic network cameras, and drones has developed rapidly, with each exceeding 10 billion RMB in scale, representing a huge market. Among these, high-definition automotive lenses occupy the most significant share. Rearview mirrors are a crucial component of automotive lenses. How to apply lens imaging technology to the practical use of automotive rearview mirrors, how to improve the temperature adaptability of automotive lenses, how to enhance the image clarity of rearview mirrors, and how to achieve wide-angle shooting while maintaining low temperature drift are pressing technical challenges in the field of rearview automotive cameras.

[0004] Furthermore, because glass lenses are relatively less affected by temperature and produce good image quality, current automotive lens temperature compensation technologies typically employ multiple individual glass lenses. However, to improve image quality, a larger number of spherical glass lenses are needed, while aspherical glass is more difficult to manufacture. In general, glass lenses offer good image quality but are expensive to produce. Aspherical plastic lenses are easier to manufacture, have lower mass production costs, and allow for a reduction in the number of lenses. Using plastic lenses can effectively control costs. However, plastic lenses are susceptible to temperature changes, have a high coefficient of thermal expansion, and exhibit significant variations at high and low temperatures, which can easily lead to image quality degradation.

[0005] Several existing patents relate to high-definition camera technology, including an intelligent high-definition camera and its monitoring system (2022112709808), an outdoor high-definition intelligent monitoring camera (2022112884135), a mobile high-definition monitoring camera (2022104165991), a day-night confocal high-definition monitoring camera (2022103722625), a high-definition artificial intelligence camera based on face recognition video processing (2019112391155), a miniature high-definition camera (2021101337351), a vehicle-mounted high-definition camera (202011370101X), and a high-definition camera (2020113821064). These existing patents all focus on camera imaging and focal length technology, and do not achieve image correction effects or high-definition image processing methods. Summary of the Invention

[0006] To address the aforementioned issues, the present invention aims to provide a high-definition, wide-view automotive electronic rearview mirror suitable for automotive systems and autonomous driving applications. It can clearly distinguish distant details, and the lens has high resolution, low distortion, and low cost, enabling clear imaging within a temperature range of -40°C to 105°C.

[0007] The objective of this invention is achieved by at least one of the following technical solutions.

[0008] A high-definition, wide-viewing-angle car rearview mirror includes a first lens, a second lens, a third lens, an aperture stop, a fourth lens, a fifth lens, a sixth lens, a seventh lens, a parallel plate, and an image plane IMA arranged sequentially along the optical axis from the object side to the image side.

[0009] The first lens has negative optical power; the second lens has negative optical power; the third lens has positive optical power; the fourth lens has positive optical power; the fifth lens has positive optical power; the sixth lens has negative optical power; and the seventh lens has positive optical power.

[0010] Furthermore, all lenses in the first, second, third, fourth, fifth, sixth, and seventh lenses are made of glass.

[0011] Furthermore, the fifth and sixth lenses are cemented together to form a cemented lens or a separate lens.

[0012] Furthermore, the car rearview mirror satisfies the following condition:

[0013] -2.2≤f1 / f≤-1.2;

[0014] -3.6≤f² / f≤-1.6;

[0015] 1.4 ≤ f3f ≤ 3.4;

[0016] 1.1≤f4 / f≤13.5;

[0017] 0.2≤f5 / f≤2.2;

[0018] -1.8≤f6 / f≤1.29;

[0019] -3.2≤f3f≤1.0

[0020] Where f1, f2, f3, f4, f5, and f6 are the focal lengths of the first lens, second lens, third lens, fourth lens, fifth lens, and sixth lens, respectively, and f is the total focal length value of the car rearview mirror.

[0021] Furthermore, the first lens satisfies the following conditions: Nd1 > 1.40, Vd1 > 36, where Nd1 is the refractive index of the first lens and Vd1 is the Abbe constant of the first lens;

[0022] The second lens satisfies the following conditions: Nd2 > 1.50, Vd2 > 36, where Nd2 is the refractive index of the second lens and Vd2 is the Abbe constant of the second lens;

[0023] The third lens satisfies the following conditions: Nd3 > 1.50, Vd3 < 36, where Nd3 is the refractive index of the third lens and Vd3 is the Abbe constant of the third lens;

[0024] The fourth lens satisfies the following conditions: Nd4 > 1.50, Vd4 > 35, where Nd4 is the refractive index of the fourth lens and Vd4 is the Abbe constant of the fourth lens;

[0025] The fifth lens satisfies the following conditions: Nd5 > 1.65, Vd5 > 16, where Nd5 is the refractive index of the fifth lens and Vd5 is the Abbe constant of the fifth lens;

[0026] The sixth lens satisfies the following conditions: Nd6 > 1.3, Vd6 < 25, where Nd6 is the refractive index of the sixth lens and Vd6 is the Abbe constant of the sixth lens;

[0027] The seventh lens satisfies the following conditions: Nd7 > 1.50, Vd7 > 36, where Nd7 is the refractive index of the seventh lens and Vd7 is the Abbe constant of the seventh lens.

[0028] Further, the vehicle rearview mirror satisfies the following condition: 0.23 < BFL / TTL ≤ 0.3, wherein BFL is the distance on the optical axis from the center of the image side surface of the last lens to the imaging surface of the vehicle rearview mirror along the incident direction of the optical axis; TTL is the distance on the optical axis from the center of the object side surface of the first lens to the imaging surface of the vehicle rearview mirror.

[0029] Further, the vehicle rearview mirror satisfies the following condition:

[0030] 0.79 ≤ FOV / h / D ≤ 0.85;

[0031] wherein FOV is the maximum field of view of the vehicle rearview mirror; D is the maximum clear aperture of the object side surface of the first lens corresponding to the maximum field of view of the vehicle rearview mirror; h is the image height corresponding to the maximum field of view of the vehicle rearview mirror.

[0032] Further, among the maximum field of view FOV of the vehicle rearview mirror, the overall focal length f of the high-definition vehicle rearview mirror and the image height h corresponding to the maximum field of view of the vehicle rearview mirror, the following relation is satisfied: 29.5 ≤ (FOV×f) / h ≤ 30.5.

[0033] Further, the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are all glass spherical lens elements, and the seventh lens is a plastic aspheric lens.

[0034] Compared with the prior art, the advantages of the present invention are:

[0035] 1. The present invention provides a high-definition large-field vehicle rearview mirror, which is suitable for the fields of vehicle systems and automatic driving, can clearly distinguish long-distance details, and has high resolving power, small distortion and low cost, and can realize clear imaging within a temperature range of 40° to 105°;

[0036] 2. In the present invention, the fifth lens and the sixth lens form a cemented lens, which can reduce or eliminate chromatic aberration and improve imaging quality; the cemented lens improves the transmittance of the lens and reduces the assembly difficulty. The sixth lens is a negative lens, which is beneficial for correcting field curvature and improving imaging quality;

[0037] 3. In the present invention, the third lens is a meniscus positive lens curved toward the diaphragm, which is conducive to receiving and deflecting light more smoothly, reducing aberration and lowering lens sensitivity, and is also beneficial for reducing the lens aperture. The fourth lens and the fifth lens are both positive lenses, which is conducive to deflecting light and reducing the length of the lens;

[0038] 4. The present invention uses the above seven lenses to form a car rearview mirror. The overall structure is simple, small in size, low in cost, and has little temperature drift. It meets the requirements of high pixel imaging and wide viewing angle, and can also correct image distortion to a certain extent. Attached Figure Description

[0039] Figure 1 This is a structural schematic diagram of a high-definition wide-angle rearview mirror provided in an embodiment of the present invention;

[0040] Figure 2 It is an image of a standard chessboard grid;

[0041] Figure 3 It is an image obtained through a high-definition, wide-view automotive electronic rearview mirror. Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] Example:

[0044] like Figure 1 As shown, this invention provides a high-definition car rearview mirror, which is provided with a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7, a parallel plate 8, and an image plane IMA 9 in sequence along the incident direction of the optical axis.

[0045] The first lens has negative optical power, and its object side is convex and its image side is concave.

[0046] The first lens 1 has negative optical power; the second lens 2 has negative optical power; the third lens 3 has positive optical power; the fourth lens 4 has positive optical power; the fifth lens 5 has positive optical power; the sixth lens 6 has negative optical power; and the seventh lens 7 has positive optical power.

[0047] An aperture stop STO is provided between the third lens and the fourth lens;

[0048] The fifth lens 5 and the sixth lens 6 are connected by a cemented lens;

[0049] Meanwhile, the high-definition car rearview mirror meets the following conditions: -2.2≤f1 / f≤-1.2, -3.6≤f2 / f≤-1.6, 1.4≤f3f≤3.4, 1.1≤f4 / f≤13.5, 0.2≤f5 / f≤2.2, -1.8≤f6 / f≤1.29, where f1 is the focal length of the first lens, f3 is the focal length of the third lens, f5 is the focal length of the fifth lens, and f is the focal length of the high-definition car lens. By reasonably matching the focal length values ​​of the lenses, it is beneficial to reduce assembly sensitivity and control the back focus drift of the lens at low or high temperatures within a very small range, thus satisfying clear imaging.

[0050] The first lens 1 has negative optical power, its object side is convex and its image side is concave. The first lens 1 is meniscus, which is beneficial for collecting light and reducing distortion, thereby improving image quality.

[0051] The second lens 2 has a negative light angle, its object side is convex, its image side is concave, and the second lens 2 is meniscus-shaped;

[0052] The third lens 3 has positive optical power, and its object side is convex, and its image side is convex.

[0053] The fourth lens has positive optical power. In this embodiment, the fourth lens 4 is a biconvex lens.

[0054] The aperture stop is positioned between the third lens 3 and the fourth lens 4, which helps to reduce the lens aperture. The third lens 3 is a meniscus positive lens that bends toward the aperture stop, which helps to receive the refracted light more smoothly, reduce aberrations, and reduce lens sensitivity. It also helps to reduce the lens aperture. The fourth lens 4 and the fifth lens 5 are both positive lenses, which help to refract light and reduce the lens length.

[0055] The fifth lens has positive optical power. In this embodiment, the fifth lens 5 is a biconvex lens.

[0056] The sixth lens has negative optical power. In this embodiment, the sixth lens 6 is a meniscus lens.

[0057] In this embodiment, the seventh lens is a biconvex lens with positive optical power, and its object side and image side are both convex.

[0058] The fifth lens 5 and the sixth lens 6 form a cemented lens, which reduces or eliminates chromatic aberration and improves image quality. The cemented lens also increases lens transmittance and reduces assembly difficulty. The sixth lens 6 is a negative lens, which helps correct field curvature and improves image quality. The optical parameters of the high-definition automotive lens provided in Example 1 are shown in Table 1 below:

[0059] Table 1

[0060]

[0061]

[0062] As can be observed from Table 1, the first lens 1 satisfies the following conditions: Nd1 = 1.49, Vd1 = 70.4, where Nd1 is the refractive index of the first lens and Vd1 is the Abbe constant of the first lens; the second lens 2 satisfies the following conditions: Nd2 = 1.54, Vd2 = 55.71, where Nd2 is the refractive index of the second lens and Vd2 is the Abbe constant of the second lens; the third lens 3 satisfies the following conditions: Nd3 = 1.76, Vd3 = 26.61, where Nd3 is the refractive index of the third lens and Vd3 is the Abbe constant of the third lens; the fourth lens 4 satisfies the following conditions: Nd4 = 1.59, Vd4 = 6. 8.3, wherein Nd4 is the refractive index of the fourth lens, and Vd4 is the Abbe constant of the fourth lens; the fifth lens 5 satisfies the following conditions: Nd5 = 1.95, Vd5 = 17.9, wherein Nd5 is the refractive index of the fifth lens, and Vd5 is the Abbe constant of the fifth lens; the sixth lens 6 satisfies the following conditions: Nd6 = 1.95, Vd6 = 17.9, wherein Nd6 is the refractive index of the sixth lens, and Vd6 is the Abbe constant of the sixth lens; the seventh lens 7 satisfies the following conditions: Nd7 = 1.54, Vd1 = 55.71, wherein Nd7 is the refractive index of the seventh lens, and Vd7 is the Abbe constant of the first lens. The parallel plate 8 satisfies the following conditions: Nd8 = 1.52, Vd8 = 64.2, wherein Nd8 is the refractive index of the parallel plate, and Vd8 is the Abbe constant of the parallel plate. The measurement parameters for the high-definition car rearview mirror provided in this embodiment are shown in Table 2 below:

[0063] Table 2

[0064]

[0065] Wherein, TTL is the distance on the optical axis from the center of the object side of the first meniscus negative lens to the imaging surface of the optical lens; f is the total focal length of the high-definition car rearview mirror; FOV is the maximum field of view of the high-definition car rearview mirror; h is the image height corresponding to the maximum field of view of the high-definition car rearview mirror; D is the maximum aperture of the object side of the first meniscus negative lens corresponding to the maximum field of view of the high-definition car rearview mirror; BFL is the distance on the optical axis from the center of the image side of the last lens of the high-definition car rearview mirror to the imaging surface of the high-definition car rearview mirror; TTL is the distance on the optical axis from the center of the object side of the first meniscus negative lens to the imaging surface of the high-definition car rearview mirror.

[0066] In one embodiment, in the high-definition car rearview mirror provided in this embodiment of the invention, such as Figure 1As shown, this invention discloses a high-definition, wide-angle automotive rearview mirror, comprising seven lenses arranged sequentially from left to right along the optical axis: a first lens 1, a second lens 2, a third lens 3, an aperture stop 9, a fourth lens 4, a fifth lens 5, a sixth lens 6, a seventh lens 7, a parallel plate 8, and an image plane IMA. The first lens has negative optical power, with a convex object-side surface and a concave image-side surface; the second lens has negative optical power, with a convex object-side surface and a concave image-side surface; the third lens has positive optical power, with a convex object-side surface and a convex image-side surface; the fourth lens has positive optical power, with a concave object-side surface and a convex image-side surface; the fifth lens has positive optical power, with a convex object-side surface and a convex image-side surface; the sixth lens has negative optical power, with a convex object-side surface and a convex image-side surface; and the seventh lens has positive optical power, with a convex object-side surface and a convex image-side surface. The sixth and seventh lenses can be cemented together to form a composite lens or can be separate lenses. The car rearview mirror composed of the above seven lenses has a simple overall structure, small size, low cost, and small temperature drift, which meets the requirements of high pixel imaging and wide viewing angle, and can also correct image distortion to a certain extent.

[0067] In one embodiment, Figure 2 It is a standard checkerboard grid image, conforming to the standard checkerboard grid requirements of the international standard ISO 16505 Road vehicles—Ergonomics and performance aspects of camera surveillance systems—Requirements and test procedures.

[0068] Figure 3 This is an image processed by a high-definition, wide-view automotive electronic rearview mirror. The image is characterized by its high clarity; the image's diagonal lines can be seen in the picture. Figure 2 The diagonal variation is relatively small, meaning the image distortion is small, indicating that this high-definition wide-angle rearview mirror has image distortion correction function.

Claims

1. A high-definition, wide-viewing-angle car rearview mirror, characterized in that, comprising a first lens (1), a second lens (2), a third lens (3), a stop (9), a fourth lens (4), a fifth lens (5), a sixth lens (6), a seventh lens (7), a parallel flat plate (8) and an image surface IMA arranged in sequence from the object side to the image side along the optical axis; said first lens (1) has negative optical power; said second lens (2) has negative optical power; said third lens (3) has positive optical power; said fourth lens (4) has positive optical power; said fifth lens (5) has positive optical power; said sixth lens (6) has negative optical power; said seventh lens (7) has positive optical power; the only optical element with optical power in said automobile rearview mirror is said seven lenses; the first lens (1), the second lens (2), the third lens (3), the fourth lens (4), the fifth lens (5) and the sixth lens (6) are all glass spherical lenses, and the seventh lens (7) is a plastic aspherical lens; said first lens (1) satisfies the following condition: Nd1=1.49, Vd1=70.4, wherein Nd1 is the refractive index of the first lens (1), and Vd1 is the Abbe number of the first lens (1); said second lens (2) satisfies the following condition: Nd2=1.54, Vd2=55.71, wherein Nd2 is the refractive index of the second lens (2), and Vd2 is the Abbe number of the second lens (2); said third lens (3) satisfies the following condition: Nd3=1.76, Vd3=26.61, wherein Nd3 is the refractive index of the third lens (3), and Vd3 is the Abbe number of the third lens (3); said fourth lens (4) satisfies the following condition: Nd4=1.59, Vd4=68.3, wherein Nd4 is the refractive index of the fourth lens (4), and Vd4 is the Abbe number of the fourth lens (4); said fifth lens (5) satisfies the following condition: Nd5=1.95, Vd5=17.9, wherein Nd5 is the refractive index of the fifth lens (5), and Vd5 is the Abbe number of the fifth lens (5); said sixth lens (6) satisfies the following condition: Nd6=1.95, Vd6=17.9, wherein Nd6 is the refractive index of the sixth lens (6), and Vd6 is the Abbe number of the sixth lens (6); said seventh lens (7) satisfies the following condition: Nd7=1.54, Vd7=55.71, wherein Nd7 is the refractive index of the seventh lens (7), and Vd7 is the Abbe number of the seventh lens (7); said automobile rearview mirror satisfies the following condition: 0.23 < BFL / TTL ≤ 0.3, wherein BFL is the distance on the optical axis from the center of the image side surface of the last lens to the imaging surface of said automobile rearview mirror along the incident direction of the optical axis; TTL is the distance on the optical axis from the center of the object side surface of said first lens (1) to the imaging surface of said automobile rearview mirror.

2. A high-definition, wide-angle car rearview mirror according to claim 1, characterized in that, said automobile rearview mirror satisfies the following conditional expression: -2.2 ≤ f1 / f ≤ -1.2; -3.6 ≤ f2 / f ≤ -1.6; 1.4 ≤ f³ / f ≤ 3.4; 1.1≤f4 / f≤13.5; 0.2≤f5 / f≤2.2; -1.8≤f6 / f≤1.29; -3.2≤f7 / f≤1.0 Where f1, f2, f3, f4, f5, f6, and f7 are the focal lengths of the first lens (1), the second lens (2), the third lens (3), the fourth lens (4), the fifth lens (5), the sixth lens (6), and the seventh lens (7), respectively, and f is the total focal length value of the car rearview mirror.

3. A high-definition, wide-angle car rearview mirror according to claim 1, characterized in that, The car rearview mirror meets the following conditions: 0.79≤FOV / h / D≤0.85; Wherein, FOV is the maximum field of view of the car rearview mirror; D is the maximum light-transmitting aperture of the object side of the first lens (1) corresponding to the maximum field of view of the car rearview mirror; and h is the image height corresponding to the maximum field of view of the car rearview mirror.

4. A high-definition, wide-angle car rearview mirror according to claim 1, characterized in that, The maximum field of view (FOV) of the car rearview mirror, the total focal length (f) of the high-definition car rearview mirror, and the image height (h) corresponding to the maximum field of view of the car rearview mirror satisfy the following condition: 29.5 ≤ (FOV × f) / h ≤ 30.

5.

5. A high-definition, wide-angle car rearview mirror according to claim 1, characterized in that, The fifth lens (5) and the sixth lens (6) are cemented together to form a cemented lens.

6. A high-definition, wide-viewing-angle car rearview mirror according to claim 1, characterized in that, The fifth lens (5) and the sixth lens (6) are separate lenses.

Images