High-definition vehicle-mounted electronic rearview mirror optical system and camera module thereof

Abstract

The utility model provides a high-definition vehicle-mounted electronic rearview mirror optical system which is composed of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, an optical filter and an imaging surface, and an aperture diaphragm is arranged between the second lens and the third lens or between the third lens and the fourth lens. The first lens, the third lens and the fourth lens have negative focal power, and the second lens, the fifth lens and the sixth lens have positive focal power. The fourth lens and the fifth lens form a glued lens, chromatic aberration can be reduced or eliminated, and the imaging quality is improved. The third lens is a negative lens, thereby facilitating correction of field curvature and improving imaging quality. And the fifth lens and the sixth lens are positive lenses, so that light can be reflected, and the length of the lens can be reduced. The automobile rearview mirror is composed of the six lenses, the overall structure is simple, the size is small, cost is low, temperature drift is small, the high-pixel imaging requirement and the large-view-angle requirement are met, and meanwhile image distortion is corrected to a certain degree.

Description

Technical Field

[0001] The utility model relates to the technical field of optical imaging equipment, in particular to a high-definition vehicle-mounted electronic rearview mirror optical system and a camera module thereof. Background Art

[0002] In recent years, with the development of my country's national economy, people are traveling more widely and more frequently. As an indispensable means of transportation, cars have become people's primary mode of transportation. With the advancement of intelligent driving, electronic rearview mirrors are gradually replacing conventional rearview mirrors as a means of collecting environmental information. Compared to traditional physical rearview mirrors, electronic rearview mirrors replace reflective mirrors with cameras, providing drivers with a wider and more flexible field of view, allowing them to more quickly and accurately assess conditions behind the vehicle. Electronic rearview mirrors provide excellent clarity even in harsh weather conditions such as heavy rain and snow. They also help reduce wind resistance and increase driving range. However, traditional lenses have a narrow field of view, capturing limited environmental information and increasing driving risks. Furthermore, their small aperture results in poor image quality in low-light conditions, making them unsuitable for all-weather use. Summary of the Invention

[0003] In order to solve the above problems, the purpose of the present invention is to provide a high-definition vehicle-mounted electronic rearview mirror optical system with high pixels and large viewing angle.

[0004] In order to achieve the above-mentioned objectives, the technical solution adopted by the present invention is: a high-definition vehicle-mounted electronic rearview mirror optical system, which is composed of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a filter and an imaging surface in sequence along the optical axis from the object plane to the image plane, and an aperture stop is provided between the second lens and the third lens or between the third lens and the fourth lens; the first lens, the third lens and the fourth lens have negative optical power, and the second lens, the fifth lens and the sixth lens have positive optical power.

[0005] Furthermore, the first lens has negative optical power, its object side surface is convex or flat, and its image side surface is concave;

[0006] The second lens has positive refractive power, its object-side surface is convex, and its image-side surface is convex;

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

[0008] The fourth lens has negative optical power, its object-side surface is concave, and its image-side surface is concave;

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

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

[0011] The second lens and the third lens may form a cemented lens with positive optical power;

[0012] The fourth lens and the fifth lens form a cemented lens with positive refractive power.

[0013] The optical system meets the following conditions:

[0014] -1.5≤f1 / f≤-0.5;

[0015] 0.5≤f2 / f≤1.5;

[0016] -4≤f3 / f≤-1.5;

[0017] -1.8≤f4 / f≤-0.5;

[0018] 0.5≤f5 / f≤1.5;

[0019] 1.2≤f6 / f≤2.5;

[0020] Among them, f1, f2, f3, f4, f5, and f6 are the focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens respectively, and f is the focal length value of the entire rearview mirror optical system.

[0021] The first lens satisfies the following conditions: Nd1>1.65, Vd1>50, wherein 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>1.95, Vd2>23, wherein 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>1.47, Vd3>42, wherein 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>1.87, Vd4<25, wherein 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>60, wherein 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>1.75, Vd6>30, wherein Nd6 is the refractive index of the sixth lens, and Vd6 is the Abbe constant of the sixth lens.

[0027] The optical system satisfies the following condition: 0.13<BFL / TTL≤0.42, where BFL is the distance from the center of the image side surface of the last lens along the incident direction of the optical axis to the imaging plane on the optical axis; TTL is the distance from the center of the object side surface of the first lens to the imaging plane on the optical axis.

[0028] The F number of the optical system is 2.0, and the total length of the lens is ≤22 mm.

[0029] A camera module comprises an optical lens, in which the above-mentioned high-definition vehicle-mounted electronic rearview mirror optical system is installed.

[0030] Compared with the prior art, the advantages of the present invention are:

[0031] 1) The present invention provides a high-definition, wide-angle automobile rearview mirror suitable for automotive systems and autonomous driving. It can clearly distinguish details at a distance, and the lens has high resolution, low distortion, and low cost, and can achieve clear imaging within a temperature range of -40°C to 105°C. 2) The cemented lens composed of the fourth lens and the fifth lens of the present invention can reduce or eliminate chromatic aberration and improve imaging quality. The cemented lens improves the lens transmittance and reduces assembly difficulty. The third lens is a negative lens, which is beneficial for correcting field curvature and improving imaging quality. 3) The side of the third lens of the present invention close to the aperture is bent toward the aperture, which is beneficial for receiving light. The fifth lens and the sixth lens are both positive lenses, which are beneficial for refracting light and reducing the length of the lens. 4) The fifth lens of the present invention uses a material with a negative refractive index temperature coefficient and increases its contribution to the optical focal length of the entire optical system, thereby reducing the temperature drift of the lens. 5) The utility model uses the above six lenses to form a car rearview mirror, which has a simple overall structure, small size, low cost, and small temperature drift. It meets the requirements of high-pixel imaging and a large viewing angle, and can also correct image distortion to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of the optical system structure of Example 1 of the present utility model;

[0033] Figure 2This is a schematic diagram of the MTF (Modulation Transfer Function) at room temperature (20°C) of Example 1 of the present invention;

[0034] Figure 3 This is a schematic diagram of the MTF (Modulation Transfer Function) at low temperature (-40°C) of Example 1 of the present invention;

[0035] Figure 4 This is a schematic diagram of the MTF (Modulation Transfer Function) at high temperature (85°C) of Example 1 of the present invention;

[0036] Figure 5 This is a distortion diagram of Example 1 of the present utility model;

[0037] Figure 6 This is a schematic diagram of relative illumination of Example 1 of the present utility model.

[0038] Figure 7 This is a schematic diagram of the optical system structure of Example 2 of the present utility model;

[0039] Figure 8 This is a schematic diagram of the MTF (Modulation Transfer Function) at room temperature (20°C) of Example 2 of the present utility model;

[0040] Figure 9 This is a schematic diagram of the MTF (Modulation Transfer Function) at low temperature (-40°C) of Example 2 of the present utility model;

[0041] Figure 10 This is a schematic diagram of the MTF (Modulation Transfer Function) at high temperature (85°C) of Example 2 of the present invention;

[0042] Figure 11 This is a distortion diagram of Example 2 of the present utility model;

[0043] Figure 12 This is a schematic diagram of relative illumination of Example 2 of the present utility model. DETAILED DESCRIPTION

[0044] The technical solution of the present utility model is described clearly and completely below with reference to the accompanying drawings and specific embodiments.

[0045] Reference Figure 1-12 As shown, a high-definition vehicle-mounted electronic rearview mirror optical system is composed of a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a filter (COVER) 11 and an imaging surface (IMA) 12 along the optical axis from the object plane to the image plane. An aperture stop (STOP) 10 is provided between the second lens and the third lens or between the third lens and the fourth lens. The first lens, the third lens and the fourth lens have negative optical power, and the second lens, the fifth lens and the sixth lens have positive optical power.

[0046] The first lens has negative optical power, its object side surface is convex or flat, and its image side surface is concave;

[0047] The second lens has positive refractive power, its object-side surface is convex, and its image-side surface is convex;

[0048] The third lens has negative optical power, its object side surface is concave, and its image side surface is concave;

[0049] The fourth lens has negative optical power, its object-side surface is concave, and its image-side surface is concave;

[0050] The fifth lens has positive refractive power, its object-side surface is convex, and its image-side surface is convex;

[0051] The sixth lens has positive refractive power, its object-side surface is convex, and its image-side surface is convex or flat;

[0052] The second lens and the third lens may form a cemented lens with positive optical power;

[0053] The fourth lens and the fifth lens form a cemented lens with positive refractive power.

[0054] The optical system meets the following conditions:

[0055] -1.5≤f1 / f≤-0.5;

[0056] 0.5≤f2 / f≤1.5;

[0057] -4≤f3 / f≤-1.5;

[0058] -1.8≤f4 / f≤-0.5;

[0059] 0.5≤f5 / f≤1.5;

[0060] 1.2≤f6 / f≤2.5;

[0061] Among them, f1, f2, f3, f4, f5, and f6 are the focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens respectively, and f is the focal length value of the entire rearview mirror optical system.

[0062] The first lens satisfies the following conditions: Nd1>1.65, Vd1>50, wherein Nd1 is the refractive index of the first lens, and Vd1 is the Abbe constant of the first lens;

[0063] The second lens satisfies the following conditions: Nd2>1.95, Vd2>23, wherein Nd2 is the refractive index of the second lens, and Vd2 is the Abbe constant of the second lens;

[0064] The third lens satisfies the following conditions: Nd3>1.47, Vd3>42, wherein Nd3 is the refractive index of the third lens, and Vd3 is the Abbe constant of the third lens;

[0065] The fourth lens satisfies the following conditions: Nd4>1.87, Vd4<25, wherein Nd4 is the refractive index of the fourth lens, and Vd4 is the Abbe constant of the fourth lens;

[0066] The fifth lens satisfies the following conditions: Nd5<1.65, Vd5>60, wherein Nd5 is the refractive index of the fifth lens, and Vd5 is the Abbe constant of the fifth lens;

[0067] The sixth lens satisfies the following conditions: Nd6>1.75, Vd6>30, wherein Nd6 is the refractive index of the sixth lens, and Vd6 is the Abbe constant of the sixth lens.

[0068] The optical system satisfies the following condition: 0.13<BFL / TTL≤0.42, where BFL is the distance from the center of the image side surface of the last lens along the incident direction of the optical axis to the imaging plane on the optical axis; TTL is the distance from the center of the object side surface of the first lens to the imaging plane on the optical axis.

[0069] The F number of the optical system is 2.0, and the total length of the lens is ≤22 mm.

[0070] A camera module comprises an optical lens, in which the above-mentioned high-definition vehicle-mounted electronic rearview mirror optical system is installed. Example 1

[0071] like Figure 1 As shown, the first lens L1 with negative focal power and the second lens L2 with positive focal power constitute the front lens group A01; the third lens L3 with negative focal power, the fourth lens L4 with negative focal power, the fifth lens L5 with positive focal power and the sixth lens L6 with positive focal power constitute the rear lens group A02; the fourth lens L4 and the fifth lens L5 constitute the second cemented lens group B02.

[0072] The aperture 10 is located between the front lens group A01 and the rear lens group A02 , and the filter 11 is located between the rear lens group A02 and the image plane 12 .

[0073] The preferred values of the relevant parameters of each lens are shown in Table 1:

[0074]

[0075] Figure 1This is a schematic diagram of the optical system structure of an embodiment of the utility model. The overall length of the system is less than 22 mm. The entire structure is small and compact, with good anti-vibration effect, and is very suitable for use in various vehicle-mounted camera systems.

[0076] Figure 2 This is a graph of the MTF (Modulation Transfer Function) at room temperature (20°C) for an embodiment of the present invention. The horizontal axis represents spatial frequency (in line pairs per millimeter (lp / mm), and the vertical axis represents the MTF value. As can be seen from the graph, the MTF curve for this embodiment has a high degree of convergence, demonstrating excellent imaging consistency across the entire image plane, enabling high-definition images to be obtained across the entire image plane. At 166 lp / mm, the overall MTF value reaches approximately 40%.

[0077] Figure 3 This is a graph of the low-temperature (-40°C) MTF (Modulation Transfer Function) curves of an embodiment of the present invention. The horizontal axis represents spatial frequency (in line pairs per millimeter (lp / mm), and the vertical axis represents MTF value. As can be seen from the graph, at -40°C, the MTF curves for all viewing fields of this embodiment remain around 30%, showing no significant decrease compared to the normal temperature of 20°C.

[0078] Figure 4 This is a graph of the MTF (Modulation Transfer Function) curve for an embodiment of the present invention at high temperature (85°C). The horizontal axis represents spatial frequency (in line pairs per millimeter (lp / mm), and the vertical axis represents MTF value. As can be seen from the graph, at 85°C, the MTF curve for all viewing fields of this embodiment remains above 30%, with no significant drop.

[0079] Figure 5 This is the distortion diagram of the present invention, where the horizontal axis represents the distortion percentage and the vertical axis represents the field of view. Figure 5 It can be seen that the distortion in the entire image plane is about 13%.

[0080] Figure 6 This is the relative illumination diagram of the present invention, where the horizontal axis represents the field of view and the vertical axis represents the relative illumination value. Figure 6 It can be seen that the relative illumination of the edge field of view is as high as 80% compared to the central field of view. Example 2

[0081] like Figure 7 As shown, the high-definition automotive lens comprises, from the object side to the image side, a front lens group A01 with negative optical focal length and a rear lens group A02 with positive optical focal length, an aperture 10 is located between the front lens group A01 and the rear lens group A02, and a filter 11 is located between the rear lens group A02 and the image plane 12.

[0082] The front lens group A01 includes a first lens L1 with negative refractive power, a second lens L2 with positive refractive power, and a third lens L3 with negative refractive power, wherein the second lens L2 and the third lens L3 form a first cemented lens group B01.

[0083] The rear lens group A02 includes a fourth lens L4 with negative refractive power, a fifth lens L5 with positive refractive power, and a sixth lens L6 with positive refractive power. The fourth lens L4 and the fifth lens L5 constitute a second cemented lens group B02.

[0084] The aperture 11 is located between the front lens group A01 and the rear lens group A02 , and the filter 11 is located between the rear lens group A02 and the image plane 12 .

[0085] The preferred values of the relevant parameters of each lens are shown in Table 2:

[0086]

[0087] Figure 7 This is a schematic diagram of the optical system structure of an embodiment of the utility model. The overall length of the system is less than 22 mm. The entire structure is small and compact, with good anti-vibration effect, and is very suitable for use in various vehicle-mounted camera systems.

[0088] Figure 8 This is a graph of the MTF (Modulation Transfer Function) at room temperature (20°C) for an embodiment of the present invention. The horizontal axis represents spatial frequency (in line pairs per millimeter (lp / mm), and the vertical axis represents the MTF value. As can be seen from the graph, the MTF curve for this embodiment has a high degree of convergence, demonstrating excellent imaging consistency across the entire image plane, enabling high-definition images to be obtained across the entire image plane. At 166 lp / mm, the overall MTF value reaches approximately 40%.

[0089] Figure 9 This is a graph of the low-temperature (-40°C) MTF (Modulation Transfer Function) curves of an embodiment of the present invention. The horizontal axis represents spatial frequency (in line pairs per millimeter (lp / mm), and the vertical axis represents MTF value. As can be seen from the graph, at -40°C, the MTF curves for all viewing fields of this embodiment remain above 40%, showing no significant decrease compared to the ambient temperature of 20°C.

[0090] Figure 10 This is a graph of the MTF (Modulation Transfer Function) at high temperature (85°C) for an embodiment of the present invention. The horizontal axis represents spatial frequency (in line pairs per millimeter (lp / mm), and the vertical axis represents MTF value. As can be seen from the graph, at 85°C, the MTF curves for all viewing fields of this embodiment remain around 30%, showing no significant decrease.

[0091] Figure 11 This is a distortion diagram of the present invention, where the horizontal axis represents the distortion percentage and the vertical axis represents the field of view. As can be seen from the diagram, the distortion in the entire image plane is about 13%.

[0092] Figure 12 This is a relative illumination diagram of the present invention, where the horizontal axis represents the field of view and the vertical axis represents the relative illumination value. As can be seen from the diagram, the relative illumination of the edge field of view relative to the center field of view is as high as 80%.

[0093] The embodiments described above are only a portion of the embodiments of the present invention, and the concept and scope of the present invention are not limited to the details of the above exemplary embodiments. Therefore, without departing from the design concept of the present invention, various modifications and improvements made by other skilled in the art based on the technical solution of the present invention should fall within the scope of protection of the present invention, and the content of the present invention is fully described in the claims.

Claims

1. A high-definition vehicle-mounted electronic rearview mirror optical system, characterized in that: The optical lens is composed of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a filter and an imaging surface in sequence from the object plane to the image plane along the optical axis. An aperture stop is provided between the second lens and the third lens or between the third lens and the fourth lens. The first lens, the third lens and the fourth lens have negative optical power, and the second lens, the fifth lens and the sixth lens have positive optical power.

2. The high-definition vehicle-mounted electronic rearview mirror optical system according to claim 1, characterized in that: The first lens has negative optical power, its object side surface is convex or flat, and its image side surface is concave; The second lens has positive refractive power, its object-side surface is convex, and its image-side surface is convex; The third lens has negative optical power, its object side surface is concave, and its image side surface is concave; The fourth lens has negative optical power, its object-side surface is concave, and its image-side surface is concave; The fifth lens has positive refractive power, its object-side surface is convex, and its image-side surface is convex; The sixth lens has positive refractive power, its object-side surface is convex, and its image-side surface is convex or flat; The second lens and the third lens may form a cemented lens with positive optical power; The fourth lens and the fifth lens form a cemented lens with positive refractive power.

3. The high-definition vehicle-mounted electronic rearview mirror optical system according to claim 1, characterized in that: The optical system meets the following conditions: -1.5≤f1 / f≤-0.5; 0.5≤f2 / f≤1.5; -4≤f3 / f≤-1.5; -1.8≤f4 / f≤-0.5; 0.5≤f5 / f≤1.5; 1.2≤f6 / f≤2.5; Among them, f1, f2, f3, f4, f5, and f6 are the focal lengths of the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens respectively, and f is the focal length value of the entire rearview mirror optical system.

4. The high-definition vehicle-mounted electronic rearview mirror optical system according to claim 1, characterized in that: The first lens satisfies the following conditions: Nd1>1.65, Vd1>50, wherein Nd1 is the refractive index of the first lens, and Vd1 is the Abbe constant of the first lens; The second lens satisfies the following conditions: Nd2>1.95, Vd2>23, wherein Nd2 is the refractive index of the second lens, and Vd2 is the Abbe constant of the second lens; The third lens satisfies the following conditions: Nd3>1.47, Vd3>42, wherein Nd3 is the refractive index of the third lens, and Vd3 is the Abbe constant of the third lens; The fourth lens satisfies the following conditions: Nd4>1.87, Vd4<25, wherein Nd4 is the refractive index of the fourth lens, and Vd4 is the Abbe constant of the fourth lens; The fifth lens satisfies the following conditions: Nd5<1.65, Vd5>60, wherein Nd5 is the refractive index of the fifth lens, and Vd5 is the Abbe constant of the fifth lens; The sixth lens satisfies the following conditions: Nd6>1.75, Vd6>30, wherein Nd6 is the refractive index of the sixth lens, and Vd6 is the Abbe constant of the sixth lens.

5. The high-definition vehicle-mounted electronic rearview mirror optical system according to claim 1, characterized in that: The optical system satisfies the following condition: 0.13<BFL / TTL≤0.42, where BFL is the distance from the center of the image side surface of the last lens along the incident direction of the optical axis to the imaging plane on the optical axis; TTL is the distance from the center of the object side surface of the first lens to the imaging plane on the optical axis.

6. The high-definition vehicle-mounted electronic rearview mirror optical system according to claim 1, characterized in that: The F number of the optical system is 2.0, and the total length of the lens is ≤22 mm.

7. A camera module, characterized in that: The optical lens comprises an optical lens in which the high-definition vehicle-mounted electronic rearview mirror optical system according to any one of claims 1 to 6 is installed.

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