A lens and an imaging device

Abstract

The application belongs to the field of optical imaging and vehicle-mounted imaging equipment, and specifically discloses a lens which comprises, from an object side to an image side, a first lens L1 with negative focal length, a second lens L2 with negative focal length, a third lens L3 with positive focal length, a fourth lens L4 with negative focal length, a fifth lens L5 with positive focal length, a sixth lens L6 with positive focal length, a seventh lens L7 with negative focal length, an eighth lens L8 with positive focal length, a ninth lens L9 with positive focal length, and a tenth lens L10 with positive focal length; an aperture stop STOP is arranged between the fifth lens L5 and the sixth lens L6; a color filter and an imaging surface are further arranged on the image side of the tenth lens L10; the focal length of the first cemented lens group G1 is f G1 ; the focal length of the second cemented lens group G2 is f G2 ; the total focal length of the optical lens is f, and the field of view is FOV; the following relationship is met:‑6.8≤ fG f 1 G × 2 f ×tan( FO 3 V )≤‑2.7.

Description

Technical Field

[0001] This invention belongs to the field of optical imaging and vehicle imaging equipment, specifically a lens and imaging device. Background Technology

[0002] With the rapid development of automotive driver assistance systems (ADAS), onboard optical lenses have become an essential means for these systems to acquire external information, and their importance cannot be ignored. To obtain external information more accurately, ADAS requires the use of higher-resolution chips.

[0003] As automotive systems become increasingly complex, lenses with high resolution, large aperture, and minimal distortion while maintaining wide viewing angles are becoming the development trend. However, current optical imaging lenses still suffer from the following problems:

[0004] 1. Existing lenses, while meeting the requirements for a wide field of view, also exhibit significant distortion.

[0005] 2. The lens aperture is small, resulting in poor image quality.

[0006] 3. The lens resolution is not high, and the image quality is average.

[0007] 4. The lens target surface is too small to be compatible with new high-resolution chips.

[0008] 5. The performance is not stable under high and low temperature conditions.

[0009] Chinese patent CN114779447A discloses an optical imaging system, a camera module, and an electronic device. The optical imaging system, along the optical axis from the object plane to the image plane, includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, and a tenth lens. The embodiments of this patent improve the imaging quality of the optical imaging system through the rational design of the refractive power and surface shape of the first to tenth lenses, achieving high resolution and a large aperture imaging effect. However, the lens of this patent has a field of view of only 54° and a large aperture, making it difficult to match with high-resolution chips, and the overall imaging effect cannot meet market demands; the large number of lenses also results in high material and processing costs.

[0010] Therefore, there is an urgent need in the market for an optical lens that combines high resolution with a wide field of view, good temperature performance, miniaturization, and low cost. Summary of the Invention

[0011] To address the aforementioned technical problems in the prior art, this invention provides a lens comprising, from the object side to the image side: a first lens L1 with negative optical power, a second lens L2 with negative optical power, a third lens L3 with positive optical power, a fourth lens L4 with negative optical power, a fifth lens L5 with positive optical power, a sixth lens L6 with positive optical power, a seventh lens L7 with negative optical power, an eighth lens L8 with positive optical power, a ninth lens L9 with positive optical power, and a tenth lens L10 with positive optical power; an aperture stop (STOP) is provided between the fifth lens L5 and the sixth lens L6; a color filter and an imaging surface are also provided on the image side of the tenth lens L10; the third lens L3 and the fourth lens L4 constitute a first cemented lens group G1; the seventh lens L7 and the eighth lens L8 constitute a second cemented lens group G2; the focal length of the first cemented lens group G1 is f. G1 The focal length of the second cemented lens group G2 is f. G2 The total focal length of this optical lens is f, and the field of view is FOV; it satisfies the following relationship:

[0012]

[0013] Furthermore, the first lens L1 is a meniscus lens; the second lens L2 is a biconcave lens; the third lens L3 is a meniscus lens; the fourth lens L4 is a meniscus lens; the fifth lens L5 is a biconvex lens; the sixth lens L6 is a biconvex lens; the seventh lens L7 is a biconcave lens; the eighth lens L8 is a biconvex lens; the ninth lens L9 is a biconvex lens; and the tenth lens L10 is a meniscus lens.

[0014] Furthermore, the second lens L2 has a concave surface on both the object side and the image side.

[0015] Furthermore, the sixth lens L6 has a convex surface on both the object side and the image side.

[0016] Furthermore, the central radius of curvature R9 of the image-side surface of the fifth lens L5 and the central radius of curvature R12 of the image-side surface of the sixth lens L6 satisfy the following:

[0017]

[0018] Furthermore, the total focal length f of the optical lens satisfies the following relationship with the total optical length TTL:

[0019] 7.1≤TTL / f≤8.4 (3).

[0020] Furthermore, the focal lengths f1 of the first lens L1, f4 of the fourth lens L4, and f10 of the tenth lens L10 of the optical lens satisfy the following formula:

[0021] f1≤-13 (4)

[0022] f4≤-18 (5)

[0023] f10≤41 (6).

[0024] Furthermore, the Abbe numbers Vd3 of the third lens L3, Vd4 of the fourth lens L4, and Vd9 of the ninth lens L9 of the optical lens satisfy the following formula:

[0025] Vd3≤35 (7)

[0026] Vd4≤29 (8)

[0027] Vd9≤71 (9).

[0028] Furthermore, the refractive indices Nd2 of the second lens L2, Nd4 of the fourth lens L4, and Nd10 of the tenth lens L10 of the optical lens satisfy the following relationship:

[0029] Nd2≤1.85 (10)

[0030] Nd4≤1.92 (11)

[0031] Nd10≤1.78 (12).

[0032] An imaging device, the imaging device including the lens described above.

[0033] Beneficial effects

[0034] I. The lens of this invention has a field of view of 80° and an aperture of no more than 1.5, thus meeting the market demand for a large field of view, a large target surface, and high resolution.

[0035] 2. The MTF value across the entire field of view reaches 0.55 or higher at 100 lp / mm.

[0036] Third, the lens adopts an all-glass design, which has good processability and lower cost control;

[0037] IV. Stable optical performance, meeting the requirements of high and low temperature working conditions from -30 to +70℃. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the structure of a lens in the prior art;

[0039] Figure 2 This is a schematic diagram of the lens structure in this application;

[0040] Figure 3This is a graph of the optical transfer function (MTF) of the first specific embodiment of the lens provided in this application in the visible light band at room temperature.

[0041] Figure 4a and Figure 4b This is a field curvature and distortion diagram in the visible light band of the first specific embodiment of the lens provided in this application;

[0042] Figure 5 This is a lateral fan pattern in the visible light band of the first specific embodiment of the lens provided in this application;

[0043] Figure 6 This is a dot plot of the first specific embodiment of the lens provided in this application in the visible light band;

[0044] Figure 7 This is a graph of the optical transfer function (MTF) of the lens provided in the second specific embodiment of the lens in the visible light band at room temperature.

[0045] Figure 8a and Figure 8b This is a field curvature and distortion diagram in the visible light band of a second specific embodiment of the lens provided in this application;

[0046] Figure 9 This is a lateral fan pattern in the visible light band of a second specific embodiment of the lens provided in this application;

[0047] Figure 10 This is a dot plot of the second specific embodiment of the lens provided in this application in the visible light band;

[0048] Figure 11 This is a schematic diagram of a specific embodiment of the imaging device provided in this application. Detailed Implementation

[0049] 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 a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0050] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0051] like Figure 2 As shown, the lens of the present invention, from the object side to the image side, includes, in sequence: a first lens L1 with negative optical power, a second lens L2 with negative optical power, a third lens L3 with positive optical power, a fourth lens L4 with negative optical power, a fifth lens L5 with positive optical power, a sixth lens L6 with positive optical power, a seventh lens L7 with negative optical power, an eighth lens L8 with positive optical power, a ninth lens L9 with positive optical power, and a tenth lens L10 with positive optical power.

[0052] An aperture stop (STOP) is provided between the fifth lens L5 and the sixth lens L6; the image side of the tenth lens L10 is also provided with a color filter and an imaging surface.

[0053] Optionally, the first lens L1 is a meniscus lens; the second lens L2 is a biconcave lens; the third lens L3 is a meniscus lens; the fourth lens L4 is a meniscus lens; the fifth lens L5 is a biconvex lens; the sixth lens L6 is a biconvex lens; the seventh lens L7 is a biconcave lens; the eighth lens L8 is a biconvex lens; the ninth lens L9 is a biconvex lens; and the tenth lens L10 is a meniscus lens.

[0054] The third lens L3 and the fourth lens L4 constitute the first cemented lens group G1; the seventh lens L7 and the eighth lens L8 constitute the second cemented lens group G2.

[0055] The focal length of the first cemented lens group G1 is f G1 The focal length of the second cemented lens group G2 is f. G2 The total focal length of this optical lens is f, and the field of view is FOV; it satisfies the following relationship:

[0056]

[0057] The second lens L2 has a concave surface on both the object side and the image side.

[0058] The sixth lens L6 has a convex surface on both the object side and the image side.

[0059] The central radius of curvature R9 of the image-side surface of the fifth lens L5 and the central radius of curvature R12 of the image-side surface of the sixth lens L6 satisfy the following:

[0060]

[0061] The total focal length f of the optical lens and the total optical length TTL satisfy the following:

[0062] 7.1≤TTL / f≤8.4 (3).

[0063] The focal lengths f1 of the first lens L1, f4 of the fourth lens L4, and f10 of the tenth lens L10 of the optical lens satisfy the following formula:

[0064] f1≤-13 (4)

[0065] f4≤-18 (5)

[0066] f10≤41 (6).

[0067] The Abbe numbers Vd3 of the third lens L3, Vd4 of the fourth lens L4, and Vd9 of the ninth lens L9 of the optical lens satisfy the following formula:

[0068] Vd3≤35 (7)

[0069] Vd4≤29 (8)

[0070] Vd9≤71 (9).

[0071] The refractive indices Nd2 of the second lens L2, Nd4 of the fourth lens L4, and Nd10 of the tenth lens L10 of the optical lens satisfy the following relationship:

[0072] Nd2≤1.85 (10)

[0073] Nd4≤1.92 (11)

[0074] Nd10≤1.78 (12).

[0075] Example 1

[0076] The radius of curvature R, center thickness Tc, refractive index Nd, Abbe constant Vd, and conic coefficient k of each lens in the optical lens of this embodiment 1 satisfy the conditions listed in Table 1:

[0077]

[0078]

[0079] Table 1 Lens Parameter Table

[0080] It should be noted that the mirror serial numbers in Table 1 are Figure 2 The diagram of the optical lens structure shown has the lens face numbers from left to right.

[0081] The lens provided in this embodiment has the following optical technical specifications:

[0082] Total optical length (TTL) ≤ 48.8 mm;

[0083] Total focal length f: 6.7mm;

[0084] Lens field of view: 80°;

[0085] Lens optical distortion: -20.8%;

[0086] The lens system's aperture Fn. is 1.5.

[0087] Lens image size: 1 / 1.8"

[0088] In this embodiment 1, the focal length of the first cemented lens group G1 of the optical lens is f. G1 The focal length of the second cemented lens group G2 is f. G2 The total focal length of the optical lens is f, and the field of view is FOV, satisfying the following: The central radius of curvature R9 of the image side of lens L5 and the central radius of curvature R11 of the object side of lens L6 satisfy the following relationship: The total focal length f of the optical lens and the total optical length TTL of the optical lens satisfy the following relationship: The focal length of the first lens L1 is f1 = -14.86mm, the focal length of the fourth lens L4 is f4 = -26.25mm, and the focal length of the tenth lens L10 is f10 = 35.47mm; the Abbe number of the third lens L3 is Vd3 = 33.28, the Abbe number of the fourth lens L4 is Vd4 = 27.53, and the Abbe number of the ninth lens L9 is Vd9 = 68.62; the refractive index of the second lens L2 is Nd2 = 1.71, the refractive index of the fourth lens L4 is Nd4 = 1.75, and the refractive index of the tenth lens L10 is Nd10 = 1.74.

[0089] Example 2

[0090] The radius of curvature R, center thickness Tc, refractive index Nd, Abbe constant Vd, and conic coefficient k of each lens in the optical lens of this embodiment 1 satisfy the conditions listed in Table 3:

[0091]

[0092]

[0093] Table 3 Lens Parameter Table

[0094] It should be noted that the mirror serial numbers in Table 3 are... Figure 2 The diagram of the optical lens structure shown has the lens face numbers from left to right.

[0095] The lens provided in this embodiment 2 has the following optical technical specifications:

[0096] Total optical length (TTL) ≤ 50.0 mm;

[0097] Total focal length f: 6.7mm;

[0098] Lens field of view: 80°;

[0099] Lens optical distortion: -21.7%;

[0100] The lens system's aperture Fn. is 1.5.

[0101] Lens image size: 1 / 1.8".

[0102] In this embodiment 2, the focal length of the optical lens with the cemented lens group G1 is f. G1 The focal length of the second cemented lens group G2 is f. G2 The total focal length of the lens is f, and the field of view is FOV, satisfying the following conditions: The central radius of curvature R9 of the image side of the fifth lens L5 and the central radius of curvature R11 of the object side of the sixth lens L6 satisfy the following: The total focal length f of the optical lens and the total optical length TTL of the optical lens satisfy the following relationship: The focal length of the first lens L1 is f1 = -19.43, the focal length of the fourth lens L4 is f4 = -20.53, and the focal length of the tenth lens L10 is f10 = 38.71; the Abbe number of the third lens L3 is Vd3 = 27.53, the Abbe number of the fourth lens L4 is Vd4 = 23.79, and the Abbe number of the ninth lens L9 is Vd9 = 60.33; the refractive index of the second lens L2 is Nd2 = 1.74, the refractive index of the fourth lens L4 is Nd4 = 1.84, and the refractive index of the tenth lens L10 is Nd10 = 1.71.

[0103] In summary, Examples 1 to 2 satisfy the relationships shown in Table 5 below.

[0104]

[0105] Table 5: Comprehensive Table of Parameter Relationships

[0106] The optical transfer function is a relatively accurate, intuitive, and common way to evaluate the imaging quality of an imaging system. The higher and smoother the curve, the better the imaging quality of the system and the better it corrects various aberrations (such as spherical aberration, coma, astigmatism, field curvature, axial chromatic aberration, and transverse chromatic aberration).

[0107] like Figure 3 As shown, the optical transfer function (MTF) curve of this optical lens in the visible light region at room temperature is relatively smooth and concentrated, and the average MTF value of the entire field of view (half-image height Y' = 4.4 mm) reaches more than 0.55; it can be seen that the optical lens provided in this embodiment can achieve high imaging requirements.

[0108] like Figure 7 As shown, the optical transfer function (MTF) curve of this optical lens in the visible light region at room temperature is relatively smooth and concentrated, and the average MTF value of the entire field of view (half-image height Y' = 4.4 mm) reaches more than 0.6; it can be seen that the optical lens provided in this embodiment can achieve high imaging requirements.

[0109] like Figure 4a and Figure 8a As shown, the field curvature of this optical lens is controlled within ±0.1mm. Field curvature is also known as "image field curvature." When a lens has field curvature, the intersection of the entire beam does not coincide with the ideal image point. Although a sharp image point can be obtained at each specific point, the entire image plane is a curved surface. T represents meridional field curvature, and S represents sagittal field curvature. The field curvature curve shows the distance from the current focal plane or image plane to the paraxial focal plane as a function of the field of view coordinates. The meridional field curvature data is the distance from the currently determined focal plane to the paraxial focal plane measured along the Z-axis, and is measured on the meridional (YZ plane). The sagittal field curvature data is the distance measured on a plane perpendicular to the meridional plane. The baseline in the schematic diagram is on the optical axis, and the top of the curve represents the maximum field of view (angle or height). No units are set on the vertical axis because the curve is always normalized using the maximum radial field of view.

[0110] like Figure 4b and Figure 8b As shown, the imaging system exhibits good distortion control, within -21.7%. Figure 3 The curves at multiple wavelengths (0.436 μm, 0.486 μm, 0.546 μm, 0.587 μm, and 0.656 μm) are referenced. Figure 3The distortion occurred in the image. Generally speaking, lens distortion is actually a general term for the inherent perspective distortion of optical lenses, that is, distortion caused by perspective. This distortion is very detrimental to the image quality of a photograph, since the purpose of photography is to reproduce, not exaggerate. However, because this is an inherent characteristic of lenses (convex lenses converge light rays, concave lenses diverge light rays), it cannot be eliminated, only improved. As shown in Figure 8, the distortion of the lens provided in Embodiment 1 of the present invention is -20.8%; the distortion of the lens provided in Embodiment 2 of the present invention is -21.7%. This distortion setting is to balance the focal length, field of view, and the size of the corresponding camera target surface. The deformation caused by distortion can be corrected through post-processing image processing.

[0111] like Figure 5 and Figure 9 As shown, the curves in the optical sector diagram are relatively concentrated, indicating that the spherical aberration and dispersion of this imaging system are well controlled.

[0112] like Figure 6 and Figure 10 As shown, the imaging system has a small and concentrated spot radius, and the corresponding aberrations and coma are also relatively good.

[0113] In summary, embodiments 1 and 2 of the present invention effectively control the cost of the imaging system and realize a high-resolution imaging system that combines a large field of view, a large aperture, a large target surface, and low cost.

[0114] like Figure 11 As shown, the imaging device 10 of this application embodiment includes at least one optical lens 11. Specifically, the optical lens 11 can be the optical lens of embodiments 1 and 2 described above, and its specific structure will not be repeated here.

[0115] The imaging device 10 in this embodiment can be applied to the field of high-precision environmental detection, for example, it can be installed on autonomous vehicles to provide high-precision environmental positioning information for autonomous vehicles. In other embodiments, the imaging device 10 can also be applied to other devices, such as drones, robotic vacuum cleaners, etc.

Claims

1. A lens, comprising, from the object side to the image side, a first lens L1 with negative optical power, a second lens L2 with negative optical power, a third lens L3 with positive optical power, a fourth lens L4 with negative optical power, a fifth lens L5 with positive optical power, a sixth lens L6 with positive optical power, a seventh lens L7 with negative optical power, an eighth lens L8 with positive optical power, a ninth lens L9 with positive optical power, and a tenth lens L10 with positive optical power; an aperture stop (STOP) is provided between the fifth lens L5 and the sixth lens L6; and a color filter and an imaging surface are further provided on the image side of the tenth lens L10; characterized in that: The third lens L3 and the fourth lens L4 constitute the first cemented lens group G1; the seventh lens L7 and the eighth lens L8 constitute the second cemented lens group G2; the focal length of the first cemented lens group G1 is... ; The focal length of the second cemented lens group G2 is The total focal length of this lens is The field of view is The following relationship must be satisfied: （1）。 2. The lens according to claim 1, characterized in that: The first lens L1 is a meniscus lens; the second lens L2 is a biconcave lens; the third lens L3 is a meniscus lens; the fourth lens L4 is a meniscus lens; the fifth lens L5 is a biconvex lens; the sixth lens L6 is a biconvex lens; the seventh lens L7 is a biconcave lens; the eighth lens L8 is a biconvex lens; the ninth lens L9 is a biconvex lens; and the tenth lens L10 is a meniscus lens.

3. The lens according to claim 1, characterized in that: The second lens L2 has a concave surface on both the object side and the image side.

4. The lens according to claim 1, characterized in that: The sixth lens L6 has a convex surface on both the object side and the image side.

5. The lens according to claim 1, characterized in that: The central radius of curvature R9 of the image-side surface of the fifth lens L5 and the central radius of curvature R12 of the image-side surface of the sixth lens L6 satisfy the following: （2）。 6. The lens according to claim 1, characterized in that: The total focal length of the lens is The following conditions must be met with the total optical length TTL: （3）。 7. The lens according to claim 1, characterized in that: The focal lengths f1 of the first lens L1, f4 of the fourth lens L4, and f10 of the tenth lens L10 satisfy the following formula: f1≤-13 （4） f4≤-18 （5） f10≤41 （6）。 8. The lens according to claim 1, characterized in that: The Abbe numbers Vd3 of the third lens L3, Vd4 of the fourth lens L4, and Vd9 of the ninth lens L9 satisfy the following formula: Vd3≤35 (7) Vd4≤29 (8) Vd9≤71 (9).

9. The lens according to claim 1, characterized in that: The refractive indices Nd2 of the second lens L2, Nd4 of the fourth lens L4, and Nd10 of the tenth lens L10 satisfy the following relationship: Nd2≤1.85 (10) Nd4≤1.92 (11) Nd10≤1.78 (12).

10. An imaging device, characterized in that, The imaging device includes the lens as described in any one of claims 1 to 9.

Images