Ultra-wide-angle ADAS optical system and imaging device

Abstract

The utility model discloses an ultra-wide-angle ADAS optical system and an imaging device, and relates to the technical field of optical systems and imaging devices, and the ultra-wide-angle ADAS optical system sequentially comprises a first lens, a second lens, a third lens, a fourth lens, a diaphragm, a fifth lens, a sixth lens, a seventh lens, an optical filter, protective glass and an image plane from an object plane to an image plane along an optical axis. The object plane side of the first lens is a convex surface, and the image plane side is a concave surface. The object surface side of the second lens is a convex surface, and the image surface side is a convex surface; the object plane side of the third lens is a concave surface, and the image plane side is a concave surface; the object plane side of the fourth lens is a convex surface, and the image plane side is a convex surface; the object plane side of the fifth lens is a convex surface, and the image plane side is a convex surface; the object plane side of the sixth lens is a convex surface, and the image plane side is a convex surface; the object plane side of the seventh lens is a concave surface, and the image plane side is a convex surface; and the sixth lens and the seventh lens form a group of glued lenses. The ultra-wide-angle ADAS optical system and the imaging device have the characteristics of large aperture, wide angle, purple edge optimization and stable thermal drift.

Description

Technical Field

[0001] The utility model relates to the technical field of optical systems and imaging devices, in particular to an ultra-wide-angle ADAS optical system and an imaging device. Background Art

[0002] Nowadays, assisted driving systems are closely integrated with the automotive field, and various assisted driving systems such as ADAS, DVR, AVM, DMS, and OMS have been developed. Among them, the ADAS assisted driving system installs various sensors (radar, single / binocular camera lenses, and satellite navigation) in the front, back, left, and right directions of the car. The auxiliary chip senses the various environments encountered by the car during driving, collects data, and identifies, detects, and tracks static and dynamic objects. It also combines navigation map data to perform systematic calculations and analysis, so that the driver can be aware of possible dangers in advance, effectively increasing the comfort and safety of car driving.

[0003] The demand for on-board ADAS assisted driving systems has increased in the market, and the technical requirements for ADAS optical lens imaging systems have also become increasingly higher. In existing on-board ADAS lens imaging technologies, the aperture is generally small, which can lead to unclear images under cloudy and low-light conditions at night, poor stability against high and low temperature thermal drifts, poor imaging effects in environments with large temperature changes, and insufficient field of view, resulting in a small shooting range and severe purple fringing at the edges of the captured scenes, which affects object recognition and tracking. Utility Model Content

[0004] The utility model proposes an ultra-wide-angle ADAS optical system and an imaging device, which have the characteristics of large aperture, wide angle, purple fringing optimization and thermal drift stability.

[0005] The above technical objectives of the utility model are achieved through the following technical solutions: an ultra-wide-angle ADAS optical system and imaging device, which includes, in sequence from the object plane to the image plane along the optical axis: a first lens, a second lens, a third lens, a fourth lens, an aperture, a fifth lens, a sixth lens, a seventh lens, a filter, a protective glass and an image plane;

[0006] The object side of the first lens is convex, and the image side is concave;

[0007] The object side of the second lens is convex, and the image side is convex;

[0008] The object side of the third lens is concave, and the image side is concave;

[0009] The fourth lens has a convex surface on its object side and a convex surface on its image side;

[0010] The fifth lens has a convex object surface side and a convex image surface side;

[0011] The sixth lens has a convex object surface side and a convex image surface side;

[0012] The seventh lens has a concave object side and a convex image side;

[0013] The sixth lens and the seventh lens form a cemented lens group;

[0014] And the following relationship is satisfied:

[0015] -2.1<f1 / f<-1.2; 3<f2 / f<4.5; -2.2<f3 / f<-1; 2<f4 / f<3; 2<f5 / f<3; -10.2<f6 / f<-9; -49.5<f7 / f<-47.5;

[0016] Among them, f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, f6 is the focal length of the sixth lens, f7 is the focal length of the seventh lens, and f is the effective focal length of the entire optical system.

[0017] In some embodiments, the refractive index Nd1 of the first lens and the refractive index Nd4 of the fourth lens are both greater than 1.85 and less than 1.95, and the Abbe constant Vd1 of the first lens and the Abbe constant Vd4 of the fourth lens are both greater than 28 and less than 40.

[0018] In some embodiments, the aperture of the optical system is 1.6.

[0019] In some embodiments, the field of view FOV of the optical system satisfies the following conditions:

[0020] 185°≤FOV≤195°.

[0021] In some embodiments, the optical system satisfies the following condition:

[0022] 2.5<L / h<3.5;

[0023] Where: L represents the total length of the optical lens, and h represents the size of the image plane.

[0024] In some embodiments, the first lens is concave-convex and has a negative optical power;

[0025] The second lens is biconvex, with a large convex surface on the object side and a small convex surface on the image side, and its optical power is positive;

[0026] The third lens is biconcave, and the object side is a concave surface without a platform, and the image side is a concave surface with a platform, and its optical power is negative;

[0027] The fourth lens is biconvex, with a small convex surface on the object side and a large convex surface on the image side, and its optical power is positive;

[0028] The fifth lens is biconvex, with a small convex surface on the object side and a large convex surface on the image side, and its optical power is positive;

[0029] The sixth lens is biconvex, with a small convex surface on the object side and a large convex surface on the image side, and its optical power is negative;

[0030] The seventh lens is meniscus-shaped and has negative refractive power.

[0031] In some embodiments, the aperture stop is disposed between the fourth lens and the fifth lens.

[0032] In summary, the utility model has the following beneficial effects:

[0033] Large aperture: The aperture of this optical system is 1.6, which can allow more light to enter, enhance the imaging ability in low-light environments, and make images clearer at night or in dark weather.

[0034] Ultra-wide-angle field of view 185°≤FOV≤195°: covers almost the entire vehicle surroundings, reduces blind spots, provides the driver with a comprehensive field of view, and enhances driving safety.

[0035] Thermal drift stability: In environments with large temperature changes, such as direct sunlight or cold weather, the optical system can still maintain stable imaging performance without image quality degradation due to temperature changes.

[0036] Edge Optimization Purple Fringing: By optimizing the optical design, the chromatic aberration at the edge of the image, especially the purple fringing phenomenon, is reduced, thereby improving the overall image quality and making objects at the edge easier to identify and track. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the lens of the utility model;

[0038] Figure 2 This is the MTF analysis diagram of the utility model;

[0039] Figure 3 This is the defocus curve diagram of the utility model at 20°C;

[0040] Figure 4 This is the defocus curve diagram of the utility model at -40°C;

[0041] Figure 5 This is the defocus curve diagram of the utility model at 85°C;

[0042] Figure 6 It is the field curvature diagram of the present utility model;

[0043] Figure 7 is the distortion diagram of the utility model;

[0044] Figure 8 This is a relative illumination diagram of the present utility model.

[0045] In the figure: E1: first lens; E2: second lens; E3: third lens; E4: fourth lens; STO (Stop): aperture; E5: fifth lens; E6: sixth lens; E7: seventh lens; IR (Infrared Filter): filter; CG (Coverglass): protective glass; IMA (Image Surface): image surface;

[0046] S1: the side of the first lens facing the object side; S2: the side of the first lens facing the image side; S3: the side of the second lens facing the object side; S4: the side of the second lens facing the image side; S5: the side of the third lens facing the object side; S6: the side of the third lens facing the image side; S7: the side of the fourth lens facing the object side; S8: the side of the fourth lens facing the image side; S10: the side of the fifth lens facing the object side; S11: the side of the fifth lens facing the image side; S12: the side of the sixth lens facing the object side; S13: the side where the sixth lens and the seventh lens are bonded to each other; S14: the side of the seventh lens facing the image side. DETAILED DESCRIPTION

[0047] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0048] In the description of the present invention, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0049] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0050] In the present invention, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0051] like Figure 1 As shown, this embodiment provides an ultra-wide-angle ADAS optical system and an imaging device, which includes, along the optical axis from the object plane to the image plane, a first lens, a second lens, a third lens, a fourth lens, an aperture, a fifth lens, a sixth lens, a seventh lens, a filter, a protective glass and an image plane;

[0052] The object side of the first lens is convex, and the image side is concave;

[0053] The object side of the second lens is convex, and the image side is convex;

[0054] The object side of the third lens is concave, and the image side is concave;

[0055] The fourth lens has a convex object surface and a convex image surface.

[0056] The fifth lens has a convex object surface side and a convex image surface side;

[0057] The sixth lens has a convex object surface side and a convex image surface side;

[0058] The seventh lens has a concave object side and a convex image side;

[0059] The sixth lens and the seventh lens form a cemented lens group;

[0060] And the following relationship is satisfied:

[0061] -2.1<f1 / f<-1.2; 3<f2 / f<4.5; -2.2<f3 / f<-1; 2<f4 / f<3; 2<f5 / f<3; -10.2<f6 / f<-9; -49.5<f7 / f<-47.5;

[0062] Among them, f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, f6 is the focal length of the sixth lens, f7 is the focal length of the seventh lens, and f is the effective focal length of the entire optical system.

[0063] As an improvement, the refractive index Nd1 of the first lens and the refractive index Nd4 of the fourth lens are both greater than 1.85 and less than 1.95, and the Abbe constant Vd1 of the first lens and the Abbe constant Vd4 of the fourth lens are both greater than 28 and less than 40.

[0064] As an improvement, the optical system has an aperture (FNO) of 1.6.

[0065] As an improvement, the field of view FOV of the optical system satisfies the following conditions:

[0066] 185°≤FOV≤195°.

[0067] As an improvement, the optical system satisfies the following conditional formula:

[0068] 2.5<L / h<3.5;

[0069] Where: L represents the total length of the optical lens, and h represents the size of the image plane.

[0070] As an improvement, the first lens is concave-convex and its optical power is negative;

[0071] The second lens is biconvex, with a large convex surface on the object side and a small convex surface on the image side, and its optical power is positive;

[0072] The third lens is biconcave, and the object side is a concave surface without a platform, and the image side is a concave surface with a platform, and its optical power is negative;

[0073] The fourth lens is biconvex, with a small convex surface on the object side and a large convex surface on the image side, and its optical power is positive;

[0074] The fifth lens is biconvex, with a small convex surface on the object side and a large convex surface on the image side, and its optical power is positive;

[0075] The sixth lens is biconvex, with a small convex surface on the object side and a large convex surface on the image side, and its optical power is negative;

[0076] The seventh lens is meniscus-shaped and has negative refractive power.

[0077] As an improvement, the aperture stop is arranged between the fourth lens and the fifth lens.

[0078] In the embodiment of the present patent, when the working distance is infinity, the total focal length of the lens is f=3.01 mm, FNO=1.6, the field of view angle FOV=191°, and the maximum image circle is 7.66 mm.

[0079] The parameters of the lens group are listed in Table 1:

[0080] Surf Radius Thickness Index ABB EFL-E OBJ INFINITY INFINITY 1 21.5 1.2 1.9 31.3 -5.294 2 3.827233117 2.775269764 3 12.11525724 1.85 2 25.4 11.04 4 -125.7 0.509085502 5 -8.32646845 0.835261085 1.55 45.8 -4.969 6 4.21646845 0.65 7 15.01927507 1.93 1.91 35.3 7.253 8 -11.17119463 0.1 STO INFINITY 0.558280045 10 18.23744988 3.3 1.59 68.3 7.41 11 -5.417092371 0.1 12 11.25936163 3.265888819 1.57 71.3 -28.934 13 -4.038698888 0.8173566 1.95 18 -146.67 14 -11.23012557 0.778635927 15 INFINITY 0.3 1.52 64.2 16 INFINITY 2.886927605 17 INFINITY 0.4 1.52 64.2 18 INFINITY 0.1 IMA INFINITY 0

[0081] In the above Table 1 of this embodiment, Radius is the radius of curvature, Thickness is the thickness, Index is the refractive index, ABB is the Abbe coefficient, and EFL-E is the focal length of the lens.

[0082] In the embodiment of the present utility model, Figure 2 The modulation transfer function (MTF) curve in the visible light band represents the comprehensive resolution ability of the optical system. The horizontal axis of the figure represents the spatial frequency, the unit is cycles per millimeter (cycles / mm), and the vertical axis represents the value of the modulation transfer function (MTF). The value of MTF is used to evaluate the imaging quality of the lens, and the value range is 0-1. It is particularly pointed out that the optical transfer function is used to evaluate the imaging quality of an optical system. The more accurate, intuitive and common way, the higher and smoother the curve is, the better the imaging quality of the system is, and the stronger the ability to restore the real image is; from Figure 2 It can be seen that when the spatial frequency of the visible light band is 100lp / mm, the MTF of the imaging area near the center is > 0.7, and the imaging quality is good. Figure 3 It is represented as the defocus curve at 20℃ in the visible light band. Figure 3 It can be seen that the MTF concentration of this lens is good, which is convenient for focusing. Figure 4 and Figure 5 It can be seen that the defocus curves at low temperature of -40℃ and high temperature of 85℃ both meet high resolution, the focus change of the defocus curve is small, and the thermal drift effect is stable;

[0083] Figure 6 Represented as a field curvature diagram, Figure 6 It can be seen that the field curvature value is controlled between -0.05mm and 0.05mm. The smaller the field curvature value, the better the imaging quality of the lens. Figure 7 Represented as a distortion diagram, the smaller the optical distortion, the smaller the deformation of the edge of the imaging image; Figure 8 Represented as a relative illumination diagram, from Figure 8 It can be seen that the maximum relative illumination of the edge field of view is greater than 50%, and clear imaging is still possible under low-light conditions at night, fully meeting the market's technical needs.

[0084] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. An ultra-wide-angle ADAS optical system and imaging device, characterized in that: The optical axis includes, from the object plane to the image plane, a first lens, a second lens, a third lens, a fourth lens, an aperture, a fifth lens, a sixth lens, a seventh lens, a filter, a protective glass and an image plane; The object side of the first lens is convex, and the image side is concave; The object side of the second lens is convex, and the image side is convex; The object side of the third lens is concave, and the image side is concave; The fourth lens has a convex object surface and a convex image surface. The fifth lens has a convex object surface side and a convex image surface side; The sixth lens has a convex surface on its object side and a convex surface on its image side; The seventh lens has a concave object side and a convex image side; The sixth lens and the seventh lens form a cemented lens group; And the following relationship is satisfied: -2.1<f1 / f<-1.2; 3<f2 / f<4.5; -2.2<f3 / f<-1; 2<f4 / f<3; 2<f5 / f<3; -10.2<f6 / f<-9; -49.5<f7 / f<-47.5; Among them, f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, f6 is the focal length of the sixth lens, f7 is the focal length of the seventh lens, and f is the effective focal length of the entire optical system.

2. The ultra-wide-angle ADAS optical system and imaging device according to claim 1, characterized in that: The refractive index Nd1 of the first lens and the refractive index Nd4 of the fourth lens are both greater than 1.85 and less than 1.95, and the Abbe constant Vd1 of the first lens and the Abbe constant Vd4 of the fourth lens are both greater than 28 and less than 40.

3. The ultra-wide-angle ADAS optical system and imaging device according to claim 1, characterized in that: The optical system has an aperture of 1.

6.

4. The ultra-wide-angle ADAS optical system and imaging device according to claim 1, characterized in that: The field of view FOV of the optical system meets the following conditions: 185°≤FOV≤195°.

5. The ultra-wide-angle ADAS optical system and imaging device according to claim 1, characterized in that: The optical system satisfies the following conditions: 2.5<L / h<3.5; Where: L represents the total length of the optical lens, and h represents the size of the image plane.

6. The ultra-wide-angle ADAS optical system and imaging device according to claim 1, characterized in that: The first lens is concave-convex and has negative optical power; The second lens is biconvex, with a large convex surface on the object side and a small convex surface on the image side, and its optical power is positive; The third lens is biconcave, and the object side is a concave surface without a platform, and the image side is a concave surface with a platform, and its optical power is negative; The fourth lens is biconvex, with a small convex surface on the object side and a large convex surface on the image side, and its optical power is positive; The fifth lens is biconvex, with a small convex surface on the object side and a large convex surface on the image side, and its optical power is positive; The sixth lens is biconvex, with a small convex surface on the object side and a large convex surface on the image side, and its optical power is negative; The seventh lens is meniscus-shaped and has negative refractive power.

7. The ultra-wide-angle ADAS optical system and imaging device according to claim 1, characterized in that: The aperture is arranged between the fourth lens and the fifth lens.

Images