A miniaturized, high-resolution, and high-light-through vehicle-mounted DMS lens

Abstract

The present invention discloses a vehicle-mounted DMS lens with miniaturization, high resolution and large aperture. Along the optical axis, a first lens L1, a second lens L2, a third lens L3 and a fourth lens L4 are sequentially arranged from the object side to the image side. Among them, the Abbe number of the first lens L1 is V1, the Abbe number of the second lens L2 is V2, the Abbe number of the third lens L3 is V3, and the Abbe number of the fourth lens L4 is V4. V1, V2, V3 and V4 satisfy the following conditions: 2.8 ≤ |V1 - V2| ≤ 11.6; 0 ≤ |V3 - V4| ≤ 40.8. The lens of the present invention realizes the optimization of optical performance and the miniaturization of the lens; and the lens of the present invention has the performance of high resolution and large aperture.

Description

Technical Field

[0001] The invention belongs to the technical field of optical lenses, and in particular relates to a miniaturized, high-resolution, and high-light-through vehicle-mounted DMS lens. Background Art

[0002] The in-vehicle DMS (Driver Monitor System) lens is mainly based on real-time monitoring of the driver's behavior and status to improve driving safety. Although the vehicle's autonomous driving capabilities are constantly improving, in L2 to L3 levels of autonomous driving, the driver is still the responsible subject for vehicle operation, so monitoring the driver's status becomes particularly important. It monitors the driver's facial expressions, eye status, head posture, etc. in real time through the in-vehicle camera to determine whether the driver is tired or distracted. With the development of autonomous driving technology, the importance of the DMS system has become increasingly prominent because it can ensure that the driver can take over control in time when the autonomous driving system cannot fully take over the vehicle. However, existing DMS optical lenses have some limitations, such as unstable performance in strong or low light conditions, and reduced monitoring accuracy under facial occlusion or extreme weather conditions.

[0003] In order to pursue high-definition images and a large field of view, some DMS lenses use a multi-lens structure, which not only increases the production cost of the lens, but also makes the lens larger and heavier. This design has limited the popularity and application of DMS systems to a certain extent, especially in compact vehicles with strict requirements on cost and space.

[0004] Although automotive DMS lens technology has played an important role in improving driving safety, it still needs to be improved and innovated in terms of high resolution, volume optimization, cost control, high relative illumination and privacy protection. With the continuous advancement of technology and the growth of market demand, DMS lenses are expected to develop in a more compact, higher resolution, higher relative illumination and lower cost direction. Summary of the invention

[0005] In view of the deficiencies of the prior art, the present invention provides a miniaturized, high-resolution, and high-light-through vehicle-mounted DMS lens.

[0006] To achieve the above object, the present invention provides the following technical solution: A miniaturized, high-resolution, and high-throughput DMS lens for vehicles, wherein a first lens L1, a second lens L2, a third lens L3, and a fourth lens L4 are sequentially arranged along the optical axis from the object side to the image side, wherein:

[0007] The first lens L1 is a biconvex positive lens or a meniscus positive lens with a convex object side surface;

[0008] The second lens L2 is a double concave negative lens;

[0009] The third lens L3 is a biconvex positive lens or a meniscus positive lens with a convex object side surface;

[0010] The fourth lens L4 is a positive meniscus lens, and its object side surface is convex;

[0011] The aperture C is located on the object side of the first lens L1 or between the second lens L2 and the third lens L3.

[0012] The Abbe number of the first lens L1 is V1, the Abbe number of the second lens L2 is V2, the Abbe number of the third lens L3 is V3, and the Abbe number of the fourth lens L4 is V4. V1, V2, V3, and V4 satisfy the following conditions: 2.8≤|V1-V2|≤11.6; 0≤|V3-V4|≤40.8.

[0013] As a specific implementation, the total focal length of the lens is f, the focal length of the first lens L1 is f1, the focal length of the fourth lens L4 is f4, and f1, f4 and f satisfy the following conditions: 0.87≤f1 / f≤1.5, 2.28≤f4 / f≤11.2.

[0014] As a specific implementation, the total focal length of the lens is f, the maximum image plane height of the lens is IH, and f and IH satisfy the following condition: f / IH≥1.9.

[0015] As a specific implementation, the maximum image plane height of the lens is IH, the total optical length of the lens is TTL, and IH and TTL satisfy the following condition: 0.22≤IH / TTL≤0.25.

[0016] As a specific implementation, the fourth lens L4 also satisfies the following condition: 0.50≤R 42 / (R 41 +R 42 )≤0.65, where R 41 R represents the radius of curvature of the object side of the fourth lens L4; 42 It represents the curvature radius of the image-side surface of the fourth lens L4.

[0017] As a specific implementation, the refractive index N of the first lens L1 is d1 Meet the following conditions: N d1 ≥1.8.

[0018] As a specific implementation, the refractive index N of the fourth lens L4 is d4 Meet the following conditions: N d4 ≤2.1.

[0019] As a specific implementation, when the first lens L1 is a positive meniscus lens and the third lens L3 is a positive meniscus lens, the aperture C is located on the object side of the first lens L1.

[0020] As a specific implementation, when the first lens L1 is a meniscus positive lens or a biconvex positive lens, and the third lens L3 is a biconvex positive lens, the aperture C is located between the second lens L2 and the third lens L3.

[0021] Compared with the prior art, the present invention provides a miniaturized, high-resolution, and high-light-through vehicle-mounted DMS lens, which has the following beneficial effects:

[0022] 1) The present invention optimizes the overall optical performance, improves the relative illumination of the lens, and makes the lens structure more compact by carefully designing the arrangement of the lenses in the optical system;

[0023] 2) The present invention uses all-glass material to construct the lens, ensuring stability and reliability during long-term use;

[0024] 3) The refractive index N of the first lens L1 in the present invention d1 ≥1.8, refractive index N of the fourth lens L4 d4 ≤2.1, which realizes the miniaturization of the optical lens and the requirement of large light transmission. In addition, by adjusting the surface curvature radius of the fourth lens L4, the shape of the lens is controlled to meet the requirement of high relative illumination.

[0025] 4) The optical power of the fourth lens L4 is reasonably controlled to make TTL ≤ 10mm, which meets the miniaturization requirement. In addition, by reasonably setting the ratio of the optical power of the first lens L1 and the fourth lens L4 to the optical power of the entire lens, the requirement of clear imaging is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the optical path diagram of the vehicle-mounted DMS lens in Example 1;

[0027] Figure 2 is an MTF resolution curve diagram of the vehicle-mounted DMS lens in Example 1;

[0028] Figure 3 Schematic diagram of relative illumination curve of the vehicle-mounted DMS lens in Example 1;

[0029] Figure 4 This is the optical path diagram of the vehicle-mounted DMS lens in Example 2;

[0030] Figure 5 is an MTF resolution curve diagram of the vehicle-mounted DMS lens in Example 2;

[0031] Figure 6 Schematic diagram of relative illumination curve of the vehicle-mounted DMS lens in Example 2;

[0032] Figure 7This is the optical path diagram of the vehicle-mounted DMS lens in Example 3;

[0033] Figure 8 is an MTF resolution curve diagram of the vehicle-mounted DMS lens in Example 3;

[0034] Fig. 9 Schematic diagram of the relative illumination curve of the vehicle-mounted DMS lens in Example 3. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] The present invention discloses a miniaturized, high-resolution, and high-light-through vehicle-mounted DMS lens, wherein a first lens L1, a second lens L2, a third lens L3, and a fourth lens L4 are sequentially arranged along the optical axis from the object side to the image side, wherein:

[0037] The first lens L1 is a biconvex positive lens or a meniscus positive lens with a convex object side surface;

[0038] The second lens L2 is a double concave negative lens;

[0039] The third lens L3 is a biconvex positive lens or a meniscus positive lens with a convex object side surface;

[0040] The fourth lens L4 is a positive meniscus lens, and its object side surface is convex;

[0041] The aperture C is located on the object side of the first lens L1 or between the second lens L2 and the third lens L3.

[0042] The Abbe number of the first lens L1 is V1, the Abbe number of the second lens L2 is V2, the Abbe number of the third lens L3 is V3, and the Abbe number of the fourth lens L4 is V4. V1, V2, V3, and V4 meet the following conditions: 2.8≤|V1-V2|≤11.6; 0≤|V3-V4|≤40.8. By reasonably setting the Abbe number of each lens in the optical system, the requirements of high resolution and high relative illumination are achieved.

[0043] In the following embodiments, the lens materials in the optical system are all glass materials with a conventional refractive index. Example 1

[0044] The vehicle-mounted DMS lens in this example is arranged in order from the object side to the image side along the optical axis: an aperture C, a first lens L1, a second lens L2, a third lens L3 and a fourth lens L4.

[0045] Among them, the first lens L1 is a positive meniscus lens, and its object side surface is convex; the second lens L2 is a double concave negative lens; the third lens is a positive meniscus lens, and its object side surface is convex; the fourth lens L4 is a positive meniscus lens, and its object side surface is convex.

[0046] The optical path diagram of the lens described in this example is shown in Figure 1 shown.

[0047] See Table 1, which lists the relevant parameters of each lens in this example, including the radius of curvature, thickness, refractive index of the material, and Abbe number:

[0048] Table 1

[0049]

[0050] Infinity means infinity.

[0051] The air distance from the aperture C to the first lens L1 is 0.1 mm, the air distance from the first lens L1 to the second lens L2 is 0.1685 mm; the air distance from the second lens L2 to the third lens L3 is 0.3394 mm; the air distance from the third lens L3 to the fourth lens is 0.1 mm, and the air distance from the fourth lens L4 to the image plane IMG is 2.0173 mm.

[0052] The technical indicators achieved by the optical system in this example are as follows:

[0053] 1) The total focal length of the lens: f = 4.3560mm;

[0054] 2) Focal length of the first lens L1: f1 = 4.9343 mm;

[0055] 3) Focal length of the fourth lens L4: f4 = 10.6645 mm;

[0056] 4) Total optical length of the lens: TTL = 9.1147 mm;

[0057] 5) Maximum image height of the optical system: IH = 2.2685 mm;

[0058] 6) The radius of curvature of the side surface of the fourth lens L4: R 41 =5.6243mm;

[0059] 7) The radius of curvature of the image side of the fourth lens L4: R 42 =8.4630mm;

[0060] In addition, by calculation, we can obtain: |V1-V2|=2.8759; |V3-V4|=0; f1 / f=1.1327; f4 / f=2.4482; f / IH=1.9202; IH / TTL=0.2489; R 42 / (R 41 +R 42 )=0.6008.

[0061] Here, 0.87≤f1 / f≤1.5 and 2.28≤f4 / f≤11.2 are required. By reasonably setting the ratio of the focal length of the first lens L1 and the fourth lens L4 to the focal length of the entire lens, the requirements for clear imaging can be achieved. By setting the Abbe numbers V1, V2, V3, and V4 of the first lens L1 to the fourth lens L4 to 2.8≤|V1-V2|≤11.6; 0≤|V3-V4|≤40.8, the requirements for high resolution and high relative illumination are achieved; f / IH≥1.9 achieves high light transmission; 0.22≤IH / TTL≤0.25, N d1 ≥1.8Achieved miniaturization; 0.50≤R 42 / (R 41 -R 42 )≤0.65 to meet the requirements of high relative illumination; N d4 ≤2.1 Use glass that is friendly to thermal drift, effectively improving the stability of the lens group.

[0062] Figure 2 , Figure 3 is the optical performance curve of this embodiment, wherein Figure 2 This is the MTF curve of the DMS lens. It can be seen from the figure that at the spatial frequency of 60pl / mm, its MTF value is greater than 0.6, indicating that the optical system has good imaging quality; Figure 3 This is the relative illumination curve of the DMS lens. It can be seen that the curve is relatively smooth. At the maximum field of view, the relative illumination value of the lens is greater than 70%. Example 2

[0063] The vehicle-mounted DMS lens in this example is arranged in order from the object side to the image side along the optical axis: a first lens L1, a second lens L2, an aperture C, a third lens L3 and a fourth lens L4.

[0064] Among them, the first lens L1 is a positive meniscus lens, and its object side surface is convex; the second lens L2 is a double concave negative lens; the third lens is a double convex positive lens; the fourth lens L4 is a positive meniscus lens, and its object side surface is convex.

[0065] The optical path diagram of the lens described in this example is shown in Figure 4 shown.

[0066] See Table 2, which lists the relevant parameters of each lens in this example, including the radius of curvature, thickness, refractive index of the material, and Abbe number:

[0067] Table 2

[0068]

[0069] Here, the air distance from the first lens L1 to the second lens L2 is 0.4500 mm; the air distance from the second lens L2 to the aperture C is 0.2002 mm; the air distance from the aperture C to the third lens L3 is 0.0357 mm; the air distance from the third lens L3 to the fourth lens L4 is 0.1000 mm; and the air distance from the fourth lens L4 to the image plane IMG is 4.1434 mm.

[0070] The technical indicators achieved by the optical system in this example are as follows:

[0071] 1) The total focal length of the lens: f = 5.6157mm;

[0072] 2) Focal length of the first lens L1: f1 = 8.2161 mm;

[0073] 3) Focal length of the fourth lens L4: f4 = 12.8247 mm;

[0074] 4) Total optical length of the lens: TTL = 9.8993mm;

[0075] 5) Maximum image height of the optical system: IH = 2.2685 mm;

[0076] 6) The radius of curvature of the side surface of the fourth lens L4: R 41 =3.5294mm;

[0077] 7) The radius of curvature of the image side of the fourth lens L4: R 42 =6.6703mm;

[0078] In addition, by calculation, we can obtain: |V1-V2|=11.5790; |V3-V4|=40.7838; f1 / f=1.4630; f4 / f=2.2837; f / IH=2.4755; IH / TTL=0.2292; R 42 / (R 41 +R 42 )=0.6540.

[0079] Figure 5 , Figure 6 is the optical performance curve of this embodiment, wherein Figure 5This is the MTF curve of the DMS lens. It can be seen from the figure that at the spatial frequency of 60pl / mm, its MTF value is greater than 0.55, indicating that the optical system has good imaging quality; Figure 6 This is the relative illumination curve of the DMS lens. It can be seen that the curve is smooth. Under the maximum field of view, the relative illumination value of the lens reaches 90% or above. Example 3

[0080] The vehicle-mounted DMS lens in this example is arranged in order from the object side to the image side along the optical axis: a first lens L1, a second lens L2, an aperture C, a third lens L3 and a fourth lens L4.

[0081] Among them, the first lens L1 is a double convex positive lens; the second lens L2 is a double concave negative lens; the third lens is a double convex positive lens; the fourth lens L4 is a meniscus positive lens, and its object side surface is convex.

[0082] The optical path diagram of the lens described in this example is shown in Figure 7 shown.

[0083] See Table 3, which lists the relevant parameters of each lens in this example, including the radius of curvature, thickness, refractive index of the material, and Abbe number:

[0084] Table 3

[0085]

[0086] Here, the air distance from the first lens L1 to the second lens L2 is 0.5000 mm; the air distance from the second lens L2 to the aperture C is 0.2200 mm; the air distance from the aperture C to the third lens L3 is 0.0500 mm; the air distance from the third lens L3 to the fourth lens L4 is 0.1000 mm; and the air distance from the fourth lens L4 to the image plane IMG is 3.3914 mm.

[0087] The technical indicators achieved by the optical system in this example are as follows:

[0088] 1) The total focal length of the lens: f = 5.8538mm;

[0089] 2) Focal length of the first lens L1: f1 = 5.1079 mm;

[0090] 3) Focal length of the fourth lens L4: f4 = 65.4840 mm;

[0091] 4) Total optical length of the lens: TTL = 9.1114mm;

[0092] 5) Maximum image height of the optical system: IH = 2.2685 mm;

[0093] 6) The radius of curvature of the side surface of the fourth lens L4: R 41 =4.6909mm;

[0094] 7) The radius of curvature of the image side of the fourth lens L4: R 42 =4.7986mm;

[0095] In addition, by calculation, we can obtain: |V1-V2|=11.5790; |V3-V4|=40.7838; f1 / f=0.8726; f4 / f=11.1865; f / IH=2.5805; IH / TTL=0.2490; R 42 / (R 41 +R 42 )=0.5057.

[0096] Figure 8 , Fig. 9 is the optical performance curve of this embodiment, wherein Figure 8 This is the MTF curve of the DMS lens. It can be seen from the figure that at the spatial frequency of 60pl / mm, its MTF value is greater than 0.5, indicating that the optical system has good imaging quality; Fig. 9 This is the relative illumination curve of the DMS lens. It can be seen that the curve is smooth and the imaging is uniform. Under the maximum field of view, the relative illumination value of the lens reaches 67% and above.

[0097] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A miniaturized, high-resolution, high-light-through vehicle-mounted DMS lens, characterized in that: The vehicle-mounted DMS lens has four lenses in total, wherein a first lens L1, a second lens L2, a third lens L3, and a fourth lens L4 are arranged in sequence from the object side to the image side along the optical axis, wherein: The first lens L1 is a biconvex positive lens or a meniscus positive lens with a convex object side surface; The second lens L2 is a double concave negative lens; The third lens L3 is a biconvex positive lens or a meniscus positive lens with a concave object side surface; The fourth lens L4 is a positive meniscus lens, and its object side surface is convex; The aperture C is located on the object side of the first lens L1 or between the second lens L2 and the third lens L3. The Abbe number of the first lens L1 is V1, the Abbe number of the second lens L2 is V2, the Abbe number of the third lens L3 is V3, and the Abbe number of the fourth lens L4 is V4. V1, V2, V3, and V4 satisfy the following conditions: 2.8≤|V1-V2|≤11.6; 0≤|V3-V4|≤40.

8. The total focal length of the lens is f, the focal length of the first lens L1 is f1, and the focal length of the fourth lens L4 is f4. The following conditions are satisfied between f1, f4, and f: 0.87≤f1 / f≤1.5, 2.28≤f4 / f≤11.2; The maximum image height of the lens is IH, the total optical length of the lens is TTL, and IH and TTL satisfy the following conditions: 0.22≤IH / TTL≤0.

25.

2. The miniaturized, high-resolution, high-light-throughput vehicle-mounted DMS lens according to claim 1, characterized in that: The total focal length of the lens is f, the maximum image height of the lens is IH, and f and IH satisfy the following condition: 1.9≤f / IH≤2.5805.

3. The miniaturized, high-resolution, high-light-throughput vehicle-mounted DMS lens according to claim 1, characterized in that: The fourth lens L4 also satisfies the following condition: 0.50≤R 42 / (R 41 +R 42 )≤0.6540, where R 41 R represents the radius of curvature of the object side of the fourth lens L4; 42 It represents the curvature radius of the image-side surface of the fourth lens L4.

4. The miniaturized, high-resolution, high-light-throughput vehicle-mounted DMS lens according to claim 1, characterized in that: The refractive index N of the first lens L1 d1 Meet the following conditions: N d1 ≥1.

8.

5. The miniaturized, high-resolution, high-light-throughput vehicle-mounted DMS lens according to claim 1, characterized in that: Refractive index N of fourth lens L4 d4 Meet the following conditions: N d4 ≤2.

1.

6. The miniaturized, high-resolution, high-light-throughput vehicle-mounted DMS lens according to claim 1, characterized in that: When the first lens L1 is a positive meniscus lens and the third lens L3 is a positive meniscus lens, the aperture C is located on the object side of the first lens L1.

7. The miniaturized, high-resolution, high-light-throughput vehicle-mounted DMS lens according to claim 1, characterized in that: When the first lens L1 is a meniscus positive lens or a biconvex positive lens, and the third lens L3 is a biconvex positive lens, the aperture C is located between the second lens L2 and the third lens L3.

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