A small vehicle-mounted lens

Abstract

The utility model discloses a small -size vehicle -mounted lens, including first lens, second lens and third lens who sets gradually from object side to image side, and satisfy following condition: 1.5<|f1 / f2|<3.5, 0.6<|f2 / f3|<0.9, 1.0<|f1 / f3|<3.0, wherein f1~f3 are the focal length of first lens to third lens successively, unit mm. The lens satisfies the small -size light -weight, big target surface, high thermal stability, small -caliber and low distortion requirement of infrared vehicle -mounted lens, and low in cost, good imaging quality, help to reduce the manufacturing difficulty and promote yield, can satisfy license plate recognition, road marking detection etc. The scene's detail detection demand.

Description

Technical Field

[0001] This utility model belongs to the field of optical lens technology, specifically relating to a small vehicle-mounted lens. Background Technology

[0002] Infrared automotive cameras, as a core component of intelligent driving perception systems, capture the thermal radiation information of target objects, enabling clear imaging in extreme environments such as complete darkness, strong glare, dense fog, rain, and snow. Compared to traditional visible light lenses, they possess unique penetration and anti-interference capabilities, effectively identifying low-contrast targets such as pedestrians and animals, and avoiding blind spots caused by high beams when meeting oncoming traffic at night, significantly improving driving safety. Currently, infrared cameras are widely used in autonomous driving night vision systems, blind spot monitoring, and severe weather warnings, becoming an indispensable technological means to achieve all-weather environmental perception.

[0003] However, existing infrared automotive lenses still face several technical bottlenecks: First, achieving high resolution often involves complex optical structures (4-6 lenses), resulting in a total optical length exceeding 10mm and high costs, making them difficult to fit into compact vehicle spaces. Second, infrared materials have a high temperature coefficient of refractive index, making them prone to defocusing and aberrations due to thermal expansion and contraction within a wide temperature range of -40℃ to +95℃, requiring additional temperature control devices and increasing system complexity. Third, miniaturization often comes at the cost of reduced resolution; when matched with 3μm pixel sensors, edge resolution is insufficient, and optical distortion exceeds 8%, making it difficult to meet the requirements of high-precision target recognition. Furthermore, existing lenses generally have large effective apertures, resulting in low light energy utilization and a sharp drop in signal-to-noise ratio in rain and fog environments, limiting their practical application effectiveness. Utility Model Content

[0004] To address the aforementioned issues, this utility model proposes a small vehicle-mounted lens that meets the requirements of small size and lightweight, large target area, high thermal stability, small aperture and low distortion for infrared vehicle-mounted lenses. It is also low in cost and has good imaging quality, which helps to reduce manufacturing difficulty and improve yield. It can meet the detailed detection needs of scenarios such as license plate recognition and road marking detection.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0006] This utility model proposes a small vehicle-mounted lens, comprising a first lens, a second lens, and a third lens arranged sequentially from the object side to the image side, and satisfying the following conditions:

[0007] 1.5<|f1 / f2|<3.5, 0.6<|f2 / f3|<0.9, 1.0<|f1 / f3|<3.0;

[0008] Where f1~f3 are the focal lengths of the first lens to the third lens, respectively, in mm.

[0009] Preferably, the first lens and the second lens both have positive optical power, the third lens has negative optical power, and the following conditions are satisfied:

[0010] 6.2 <f1<7.5,1.5<f2<4.5,-6.5<f3<-2.0。

[0011] Preferably, the small vehicle-mounted lens also meets the following conditions:

[0012] 1.0 <R 11 <6.8, -6.5 <R 21 <0, 1.0 <R 31 <8.5;

[0013] 8 <R 12 <45, -6.5 <R 22 <0,0 <R 32 <5;

[0014] Among them, R 11 R 21 R 31 R represents the object-side surface radii of curvature of the first, second, and third lenses, respectively. 12 R 22 R 32 The radii of curvature of the image-side surfaces of the first, second, and third lenses, respectively, are in mm.

[0015] Preferably, the first lens is a glass spherical lens, and the second and third lenses are plastic aspherical lenses.

[0016] Preferably, the mirror surfaces of the second and third lenses satisfy the following aspherical equation:

[0017] ;

[0018] In the formula, Z For the arrow height, c For curvature, y Radial coordinates, k The coefficients of the conic conic section are... A i These are the coefficients of higher-order terms.

[0019] Preferably, the small vehicle-mounted lens also meets the following conditions:

[0020] 1.55 <n d1 <1.75, 1.52 <n d2 <1.68, 1.52 <n d3 <1.68;

[0021] Where, n d1~n d3 The refractive indices are, in order, those of the first lens to the third lens.

[0022] Preferably, the small vehicle-mounted lens also meets the following conditions:

[0023] 35 <v d1 <65, 20 <v d2 <40, 30 <v d3 <60;

[0024] Among them, v d1 ~v d3 The Abbe numbers are for the first lens, then the third lens, in that order.

[0025] Preferably, an aperture stop is provided between the first lens and the second lens.

[0026] Preferably, the small vehicle-mounted lens also meets the following conditions:

[0027] 0.65 <SL / TTL<0.95,0.25<Bfl / TTL<0.4, 0.75<IH / TTL<0.9;

[0028] Where SL is the distance from the aperture stop to the image plane, Bfl is the back focal length, TTL is the total optical length, and IH is the maximum image height of the target surface of the small vehicle lens, all in mm.

[0029] Preferably, the operating wavelength of the small vehicle-mounted lens is 900nm~980nm.

[0030] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0031] 1) Balance between compact design and high resolution: By rationally configuring the focal length ratio, especially by adopting a 1G2P architecture and a reasonable distribution of optical power (positive-positive-negative), low optical distortion across the entire field of view is achieved under ultra-miniaturization conditions, with the total optical length TTL compressed to 7.64mm and the effective aperture reduced to within φ6mm. Aspherical plastic lenses (second and third lenses) are used to correct higher-order aberrations (such as spherical aberration and field curvature), and a glass spherical lens (first lens) is used to balance dispersion, resulting in an MTF ≥0.2 at 160lp / mm (within 0.95F). This allows for compatibility with 2MP sensors (3μm×3μm pixels), with a maximum optical distortion ≤5.2%, accurately matching the target surface, meeting the high-definition imaging requirements of license plate recognition and road marking detection, while simultaneously reducing tolerance sensitivity and cost, and improving manufacturing yield.

[0032] 2) Synergistic Optimization of Thermal Stability and Low Cost: By combining infrared glass (first lens) with a low refractive index temperature coefficient (dn / dT) with high-temperature resistant plastic materials, and through the synergistic design of Abbe number and refractive index, clear imaging without heat is achieved over a wide temperature range of -40℃ to +95℃, eliminating the need for an additional temperature control module and reducing system complexity and cost. The plastic aspherical lens is manufactured using injection molding, significantly reducing material and manufacturing costs. Simultaneously, it can be integrated with external structural designs (such as lens barrels) to improve shock resistance and adapt to harsh automotive operating conditions.

[0033] 3) Enhanced optical path efficiency and adaptability: Through aperture stop position optimization (SL / TTL=0.65~0.95) and back focus control (Bfl / TTL=0.25~0.4), a large light throughput is achieved at small apertures of F-number ≤2.0, improving the signal-to-noise ratio in rain and fog scenes. Simultaneously, a gradient design constraining the decreasing aperture of the front lens group (first lens) and increasing aperture of the rear lens groups (second and third lenses) reduces the difficulty of edge processing of the plastic lens. Combined with a maximum image height (6.8mm), it adapts to mainstream 1 / 2.7-inch sensors, avoiding wasted field of view. The plastic aspherical lens bears the main optical power, reducing glass usage, and the improved assembly tolerances at both ends significantly reduce mass production difficulty. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the structure of the small vehicle-mounted lens in Embodiment 1 of this utility model;

[0035] Figure 2 This is a longitudinal spherical aberration diagram of Embodiment 1 of this utility model;

[0036] Figure 3 This is a field curvature and distortion diagram of Embodiment 1 of this utility model;

[0037] Figure 4 This is the MTF diagram of Embodiment 1 of this utility model;

[0038] Figure 5 This is a schematic diagram of the structure of the small vehicle-mounted lens in Embodiment 2 of this utility model;

[0039] Figure 6 This is a longitudinal spherical aberration diagram of Embodiment 2 of this utility model;

[0040] Figure 7 This is a field curvature and distortion diagram of Embodiment 2 of this utility model;

[0041] Figure 8 This is the MTF diagram of Embodiment 2 of this utility model.

[0042] Reference numerals: L1, first lens; L2, second lens; L3, third lens; STO, aperture stop; IR, filter; CG, protective glass; IMA, image plane. Detailed Implementation

[0043] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0044] It should be noted that, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application.

[0045] like Figures 1-8 As shown, a small vehicle-mounted lens includes a first lens L1, a second lens L2, and a third lens L3 arranged sequentially from the object side to the image side, and satisfies the following conditions:

[0046] 1.5<|f1 / f2|<3.5, 0.6<|f2 / f3|<0.9, 1.0<|f1 / f3|<3.0;

[0047] Where f1~f3 are the focal lengths of the first lens L1 to the third lens L3, respectively, in mm.

[0048] This compact vehicle-mounted lens comprises three lenses: a first lens L1, a second lens L2, and a third lens L3. The first lens L1, acting as the object-side lens, receives incident light from all fields of view and converges it towards the optical axis, significantly reducing the divergence angle and providing initial collimation for subsequent lens groups. The second lens L2 receives the light converged by the first lens L1, further enhancing the converging capability and compensating for aberrations. The third lens L3, located closer to the image side, compensates for the excessive convergence of the first two positive lenses, expands the light propagation path, increases the back focal length, and reserves space for infrared filters or dual-mode sensors. By rationally setting the focal length ratio of each lens, low optical distortion across the entire field of view and high image quality are achieved under ultra-miniaturization conditions, meeting the requirements for high-precision target recognition.

[0049] In one embodiment, the first lens L1 and the second lens L2 both have positive optical power, and the third lens L3 has negative optical power, satisfying the following condition:

[0050] 6.2 <f1<7.5,1.5<f2<4.5,-6.5<f3<-2.0。

[0051] In this system, the first lens L1 has a positive optical power, and light rays converge toward the optical axis after passing through it. The second lens L2 also has a positive optical power and receives the light rays converged by the first lens L1, further enhancing the converging ability. The third lens L3 has a negative optical power and works in conjunction with the second lens L2 to balance field curvature and distortion. The combination of negative and positive optical power shortens the overall optical length while maintaining high resolution.

[0052] In one embodiment, the small vehicle-mounted lens also satisfies the following condition:

[0053] 1.0 <R 11 <6.8, -6.5 <R 21 <0, 1.0 <R 31 <8.5;

[0054] 8 <R 12 <45, -6.5 <R 22 <0,0 <R 32 <5;

[0055] Among them, R 11 R 21 R 31 R represents the radii of curvature of the object surface of the first lens L1, the second lens L2, and the third lens L3, respectively. 12 R 22 R 32 The radii of curvature of the image-side surfaces of the first lens L1, the second lens L2, and the third lens L3 are, in mm, respectively.

[0056] In one embodiment, the first lens L1 is a glass spherical lens, and the second lens L2 and the third lens L3 are plastic aspherical lenses.

[0057] This small automotive lens adopts a 1G2P architecture (one glass lens and two plastic lenses). The first lens, L1, features a spherical design that gently deflects light rays from the center field of view while increasing the incident angle of light rays from the edges. By carefully controlling the radius of curvature, excessive bending that could lead to spherical aberration accumulation is avoided. The second lens, L2, compensates for higher-order aberrations through its aspherical surface shape. The aspherical coefficients finely control the path of edge light rays, resulting in more uniform focusing of light rays from the center and edges of the field of view. The plastic aspherical injection molding process allows for complex surface machining. Through a gradient aperture design (the aperture of the second lens L2 is approximately 20% smaller than that of the first lens L1, to φ4.6mm), material usage and weight are reduced, allowing for an ultra-thin overall optical length. Higher-order aberrations of the aspherical surface (such as...) A4. Negative compensation effectively corrects the residual barrel distortion of the first lens L1, while balancing field curvature, ensuring maximum distortion ≤5% across the entire field of view. The increasing aperture design of the third lens L3 matches the image plane expansion requirements, while aspherical edge thickness control avoids injection molding deformation, ensuring optical axis consistency; the thermal expansion coefficient of the plastic material matches the lens barrel material, reducing the risk of defocusing due to temperature changes and achieving a heat-free design; it utilizes higher-order aspherical terms (such as...) A (6. Positive compensation) Corrects the remaining pincushion distortion to ensure that the distortion across the entire field of view is ≤5%; its aspherical curvature optimizes the incident angle of edge rays, reduces the angle between the principal ray and the normal to the image plane, and improves the uniformity of edge illumination.

[0058] In one embodiment, the mirror surfaces of the second lens L2 and the third lens L3 satisfy the following aspherical equation:

[0059] ;

[0060] In the formula, Z For the arrow height, c For curvature, y Radial coordinates, k The coefficients of the conic conic section are... A i These are the coefficients of higher-order terms.

[0061] In one embodiment, the small vehicle-mounted lens also satisfies the following condition:

[0062] 1.55 <n d1 <1.75, 1.52 <n d2 <1.68, 1.52 <n d3 <1.68;

[0063] Where, n d1 ~n d3 The refractive indices are, in order, those of the first lens L1 to the third lens L3.

[0064] In one embodiment, the small vehicle-mounted lens also satisfies the following condition:

[0065] 35 <v d1 <65, 20 <v d2 <40, 30 <v d3 <60;

[0066] Among them, v d1 ~v d3 The Abbe numbers are, in order, those of the first lens L1 to the third lens L3.

[0067] In one embodiment, an aperture stop STO is further provided between the first lens L1 and the second lens L2. The rear-positioned aperture stop STO further constrains the incident angle of the principal ray, suppresses astigmatism, and facilitates adjustment of the light flux.

[0068] In one embodiment, the small vehicle-mounted lens further meets the following conditions:

[0069] 0.65 < SL / TTL < 0.95, 0.25 < Bfl / TTL < 0.4, 0.75 < IH / TTL < 0.9;

[0070] Where, SL is the distance from the aperture stop STO to the image plane, Bfl is the back focal length, TTL is the total optical length, and IH is the maximum image height of the target surface of the small vehicle-mounted lens, and the unit of all is mm.

[0071] When the small vehicle-mounted lens meets 0.65 < SL / TTL < 0.95, the aperture stop STO is close to the image plane, which can limit the incident height of marginal rays, suppress field curvature and distortion (such as astigmatism in the marginal field), and at the same time optimize the uniformity of image plane illuminance to avoid vignetting; the后置 aperture stop STO (larger SL) can shorten the aperture of the front lens group (the first lens L1) and compress the front-end volume of the lens; however, it is necessary to avoid the increase in the aperture of the rear lens group (the second lens L2 and the third lens L3) caused by excessive rearward movement, and achieve a balance between miniaturization and aberration control through proportional constraints; in the design, the position of the aperture stop STO directly affects the incident angle of the chief ray, and this ratio ensures that under a limited TTL, the aperture stop STO can both constrain the marginal rays and avoid insufficient back focal length caused by being too far back, so that the sensor or filter cannot be accommodated. When 0.25 < Bfl / TTL < 0.4, the back focal length needs to be long enough to accommodate the filter (such as an infrared filter), sensor packaging and assembly tolerances. Meeting the lower limit of the ratio can ensure that the minimum back focal length > 2 mm, which is suitable for mainstream 1 / 2.7-inch sensors; when the back focal length is too long above the upper limit, the defocus effect caused by temperature change will be amplified, and the risk of thermal drift is suppressed through the upper limit of the ratio; in an ultra-thin lens, the back focal length needs to take into account the sensor space and thermal expansion tolerance; this ratio ensures the compactness of the rear mechanical structure and at the same time reserves a safety gap for the expansion of the lens barrel under wide temperature (-40 °C ~ +95 °C). When 0.75 < IH / TTL < 0.9, IH / TTL > 0.75 indicates that the image height and the TTL height match, avoiding redundancy of the total optical length or waste of the image plane and improving the light energy utilization rate; a high image height ratio requires a wide-angle design, but the upper limit of the ratio restricts the stretching of the marginal field of view to avoid excessive distortion caused by excessive pursuit of image plane coverage; when adapting to a 2MP sensor (pixel 3μm), it is necessary to ensure that the image height of 6.8 mm accurately covers the sensor target surface (diagonal is about 7.6 mm). This ratio achieves the balance of high resolution and low distortion within a limited TTL by optimizing the optical path.

[0072] In one embodiment, the working wavelength band of the small vehicle-mounted lens is 900 nm ~ 980 nm.

[0073] The following is a detailed description through specific embodiments.

[0074] Example 1:

[0075] like Figure 1 As shown, the small vehicle-mounted lens in this embodiment includes a first lens L1, an aperture stop STO, a second lens L2, and a third lens L3 arranged sequentially along the optical axis. A filter IR and a protective glass CG are also provided between the third lens L3 and the image plane IMA. These can be arranged in any order. In this embodiment, the protective glass CG is positioned close to the image plane IMA, and the filter IR and the protective glass CG are made of the same material. The optical parameters of each lens are shown in Table 1, and the aspherical coefficients are shown in Table 2. The aspherical coefficients include the conic conic coefficient. k coefficients of higher-order terms A i .

[0076] Table 1

[0077]

[0078] Table 2

[0079]

[0080] like Figure 1 As shown, surface numbers S1, S4, S6, S8, and S10 represent the object-side surfaces of the first lens L1, the second lens L2, the third lens L3, the filter IR, and the protective glass CG, respectively. Surface numbers S2, S5, S7, S9, and S11 represent the image-side surfaces of the first lens L1, the second lens L2, the third lens L3, the filter IR, and the protective glass CG, respectively. STO represents the aperture stop, i.e., surface number S3, and surface number 12 represents the imaging surface (image plane IMA) of the sensor. In Table 2, L2S1 and L2S2 are the object-side surface (S4) and image-side surface (S5) of the second lens L2, respectively, and L3S1 and L3S2 are the object-side surface (S6) and image-side surface (S7) of the third lens L3, respectively.

[0081] Figure 2 This is a longitudinal spherical aberration diagram for a small automotive lens, which shows the deviation of the convergence point of light of different wavelengths after passing through the lens. The vertical axis of the longitudinal spherical aberration diagram represents the normalized pupil coordinates from the pupil center to the pupil edge, and the horizontal axis represents the distance (in mm) from the image plane to the intersection of the ray and the optical axis. As can be seen from the longitudinal spherical aberration diagram, the degree of convergence point deviation of light of different wavelengths in this embodiment tends to be consistent, and the blur spots or color halos in the image are effectively suppressed, with small differences between single wavelengths and polychromatic wavelengths. Figure 3This is the field curvature diagram of a small automotive lens, where the S-curve represents the sagittal field curvature at wavelengths of 900nm-980nm, and the T-curve represents the meridional field curvature at wavelengths of 900nm-980nm. As shown in the figure, the lens has low field curvature, and both field curvature and astigmatism are well corrected across all fields of view. Figure 3 It also includes the optical system distortion diagram. As can be seen from the diagram, the image distortion caused by the main beam is small, and the imaging quality of the system is excellent. Figure 4 The graph shows the relationship between MTF and frequency under different fields of view. The center and edges of the field of view maintain clear imaging at various frequencies. At the limiting frequency of 160 lp / mm, the MTF within a 0.95F field of view is greater than 0.2. In summary, the longitudinal spherical aberration, field curvature, and distortion of this optical system are well controlled, resulting in excellent imaging quality.

[0082] Example 2:

[0083] like Figure 5 As shown, the small vehicle-mounted lens in this embodiment includes a first lens L1, an aperture stop STO, a second lens L2, and a third lens L3 arranged sequentially along the optical axis. A filter IR and a protective glass CG are also provided between the third lens L3 and the image plane IMA. These can be arranged in any order. In this embodiment, the protective glass CG is positioned close to the image plane IMA, and the filter IR and the protective glass CG are made of the same material. The optical parameters of each lens are shown in Table 3, and the aspherical coefficients are shown in Table 4. The aspherical coefficients include the conic conic coefficient. k coefficients of higher-order terms A i .

[0084] Table 3

[0085]

[0086] Table 4

[0087]

[0088] like Figure 5As shown, surface numbers S1, S4, S6, S8, and S10 represent the object-side surfaces of the first lens L1, the second lens L2, the third lens L3, the filter IR, and the protective glass CG, respectively. Surface numbers S2, S5, S7, S9, and S11 represent the image-side surfaces of the first lens L1, the second lens L2, the third lens L3, the filter IR, and the protective glass CG, respectively. STO represents the aperture stop, i.e., surface number S3, and surface number 12 represents the imaging surface (image plane IMA) of the sensor. In Table 4, L2S1 and L2S2 are the object-side surface (S4) and image-side surface (S5) of the second lens L2, respectively, and L3S1 and L3S2 are the object-side surface (S6) and image-side surface (S7) of the third lens L3, respectively.

[0089] Figure 6 This is a longitudinal spherical aberration diagram for a small automotive lens, which shows the deviation of the convergence point of light of different wavelengths after passing through the lens. The vertical axis of the longitudinal spherical aberration diagram represents the normalized pupil coordinates from the pupil center to the pupil edge, and the horizontal axis represents the distance (in mm) from the image plane to the intersection of the ray and the optical axis. As can be seen from the longitudinal spherical aberration diagram, the degree of convergence point deviation of light of different wavelengths in this embodiment tends to be consistent, and the blur spots or color halos in the image are effectively suppressed, with small differences between single wavelengths and polychromatic wavelengths. Figure 7 This is the field curvature diagram of a small automotive lens, where the S-curve represents the sagittal field curvature at wavelengths of 900nm-980nm, and the T-curve represents the meridional field curvature at wavelengths of 900nm-980nm. As shown in the figure, the lens has low field curvature, and both field curvature and astigmatism are well corrected across all fields of view. Figure 7 It also includes the optical system distortion diagram. As can be seen from the diagram, the image distortion caused by the main beam is small, and the imaging quality of the system is excellent. Figure 8 The graph shows the relationship between MTF and frequency under different fields of view. The center and edges of the field of view exhibit clear imaging at various frequencies, and the MTF within a 0.95F field of view at the limiting frequency of 160 lp / mm is greater than 0.2. In summary, the longitudinal spherical aberration, field curvature, and distortion of this optical system are well controlled, resulting in excellent imaging quality.

[0090] In summary, this lens adopts a 1G2P architecture and systematically solves the contradictions between miniaturization, high resolution, low cost and environmental adaptability of automotive infrared lenses through optical power allocation (positive-positive-negative), material co-design and optical path optimization. Its core advantages are as follows: By rationally setting the lens and focal length ratio, the total optical length is compressed to 7.64mm, and the effective optical aperture is within φ6mm. Combining one glass lens and two injection-molded plastic aspherical lenses, the cost and weight are reduced compared to the traditional 4-6 all-glass solution, meeting the compatibility of ultra-miniaturization and low cost. Through aspherical high-order aberration compensation and aperture stop position optimization, low optical distortion and MTF≥0.2@160lp / mm (within 0.95F) are achieved, which is compatible with 2MP sensors (3μm×3μm pixels) and meets the high-definition requirements of license plate recognition and road marking detection. The first lens L1 uses high transmittance and high temperature resistant glass, combined with the thermal expansion matching design of plastic materials, to achieve thermal imaging in a wide temperature range of -40℃ to +95℃, meeting the requirements of wide spectrum and strong environmental adaptability. It can also meet the requirements of vehicle ISO by combining with a shock-resistant structure. The lens conforms to the 16750-3 standard and is compatible with 1 / 2.7-inch sensors (6.8mm image height) through back focal ratio control, improving light energy utilization and enhancing the signal-to-noise ratio in rain and fog scenes, providing reliable all-weather perception for autonomous driving. This lens meets the requirements of low-cost, high-reliability DMC systems.

[0091] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0092] The embodiments described above are merely specific and detailed examples of the embodiments described in this application, and should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. Therefore, the scope of protection of this patent application should be determined by the appended claims.

Claims

1. A small vehicle-mounted lens, characterized in that: The small vehicle-mounted lens includes a first lens (L1), a second lens (L2), and a third lens (L3) arranged sequentially from the object side to the image side, and satisfies the following conditions: 1.5<|f1 / f2|<3.5, 0.6<|f2 / f3|<0.9, 1.0<|f1 / f3|<3.0; Where f1~f3 are the focal lengths of the first lens (L1) to the third lens (L3) respectively, in mm.

2. The small vehicle-mounted lens as described in claim 1, characterized in that: The first lens (L1) and the second lens (L2) both have positive optical power, and the third lens (L3) has negative optical power, and satisfies the following condition: 6.2 <f1<7.5,1.5<f2<4.5,-6.5<f3<-2.0。 3. The small vehicle-mounted lens as described in claim 1, characterized in that: The small vehicle-mounted camera also meets the following conditions: 1.0<R 11 <6.8,-6.5<R 21 <0,1.0<R 31 <8.5; 8<R 12 <45,-6.5<R 22 <0,0<R 32 <5; Among them, R 11 R 21 R 31 R represents the radii of curvature of the object-side surfaces of the first lens (L1), the second lens (L2), and the third lens (L3), respectively. 12 R 22 R 32 The radii of curvature of the image side surfaces of the first lens (L1), the second lens (L2), and the third lens (L3) are in mm, respectively.

4. The small vehicle-mounted lens as described in claim 1, characterized in that: The first lens (L1) is a glass spherical lens, and the second lens (L2) and the third lens (L3) are plastic aspherical lenses.

5. The small vehicle-mounted lens as described in claim 4, characterized in that: The mirror surfaces of the second lens (L2) and the third lens (L3) satisfy the following aspherical equation: ； In the formula, Z For the arrow height, c For curvature, y Radial coordinates, k The coefficients of the conic conic section are... A i These are the coefficients of higher-order terms.

6. The small vehicle-mounted lens as described in claim 1, characterized in that: The small vehicle-mounted camera also meets the following conditions: 1.55<n d1 <1.75,1.52<n d2 <1.68,1.52<n d3 <1.68; Where, n d1 ~n d3 The refractive indices are, in order, those of the first lens (L1) to the third lens (L3).

7. The small vehicle-mounted lens as described in claim 1, characterized in that: The small vehicle-mounted camera also meets the following conditions: 35<v d1 <65,20<v d2 <40,30<v d3 <60; Among them, v d1 ~v d3 The Abbe numbers are, in order, the first lens (L1) to the third lens (L3).

8. The small vehicle-mounted lens as described in claim 1, characterized in that: An aperture stop (STO) is also provided between the first lens (L1) and the second lens (L2).

9. The small vehicle-mounted lens as described in claim 8, characterized in that: The small vehicle-mounted camera also meets the following conditions: 0.65 <SL / TTL<0.95,0.25<Bfl / TTL<0.4, 0.75<IH / TTL<0.9; Wherein, SL is the distance from the aperture stop (STO) to the image plane, Bfl is the back focal length, TTL is the total optical length, and IH is the maximum image height of the target surface of the small vehicle-mounted lens, all in mm.

10. The small vehicle-mounted lens as described in claim 1, characterized in that: The operating wavelength of the small vehicle-mounted lens is 900nm~980nm.

Images