Wide-angle super-definition DVR optical lens imaging system

Abstract

The utility model discloses a wide-angle ultra-definition DVR optical lens imaging system, which relates to the technical field of optical systems and vehicle-mounted imaging devices and sequentially comprises a first lens, a second lens, a third lens, a diaphragm, a fourth lens, 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 plane side of the second lens is a concave surface, and the image plane side is a concave surface; the object plane side of the third lens is a convex surface, and the image plane side is a convex surface; the object plane side of the fourth lens is a plane, and the image plane side is a convex surface; the object plane side of the fifth lens is a concave 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 surface side of the seventh lens is a convex surface, and the image surface side is a concave surface; wherein the fourth lens and the fifth lens form a group of glued lenses. The wide-angle super-definition DVR optical lens imaging system has the characteristics of super wide angle, large aperture, super-definition pixel and stable thermal drift.

Description

Technical Field

[0001] The utility model relates to the technical field of optical systems and vehicle-mounted imaging devices, in particular to a wide-angle ultra-clear DVR optical lens imaging system. Background Art

[0002] At present, with the development and application of audio and video coding technology in vehicles, vehicle-mounted DVR has also become an emerging special product, which is widely used in various types of vehicles such as cars, trucks, buses, sanitation vehicles, etc. It can monitor vehicles in real time, including audio and video recording and real-time transmission, GPS positioning, accident alarm and other functions, and can also be connected to various sensors, display screens, passenger flow statistics and other vehicle-mounted equipment. The optical lens imaging system is an important core component of the vehicle-mounted DVR, and people are constantly improving the technical indicators of optical lenses. The existing vehicle-mounted DVR optical lens imaging technology generally has problems such as small field of view, low imaging pixels, small aperture, and poor imaging effect in high or low temperature environments. Utility Model Content

[0003] The utility model provides a wide-angle ultra-clear DVR optical lens imaging system, which has the characteristics of ultra-wide angle, ultra-clear, large aperture, and basically unchanged resolution under high and low temperature environments.

[0004] The above technical objectives of the utility model are achieved through the following technical solutions: a wide-angle ultra-clear DVR optical lens imaging system, which includes, along the optical axis from the object plane to the image plane, a first lens, a second lens, a third lens, an aperture, a fourth lens, a fifth lens, a sixth lens, a seventh lens, a filter, a protective glass and an image plane;

[0005] The object side of the first lens is convex, and the image side is concave;

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

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

[0008] The fourth lens has a flat surface on its object side and a convex surface on its image side;

[0009] The fifth lens has a concave object surface and a convex image surface;

[0010] The sixth lens has a convex surface on its object side and a convex surface on its image side;

[0011] The seventh lens has a convex object side and a concave image side;

[0012] The fourth lens and the fifth lens form a cemented lens;

[0013] And the following relationship is satisfied:

[0014] 1.58<Nd1<1.65; 1.44<Nd2<1.52; 1.91<Nd3<1.99; 1.53<N d4<1.61; 1.9<Nd5<1.98; 1.55<Nd6<1.63; 1.73<Nd7<1.8;

[0015] Among them, Nd1 is the refractive index of the first lens, Nd2 is the refractive index of the second lens, Nd3 is the refractive index of the third lens, Nd4 is the refractive index of the fourth lens, Nd5 is the refractive index of the fifth lens, Nd6 is the refractive index of the sixth lens, and Nd7 is the refractive index of the seventh lens.

[0016] In some embodiments, the Abbe constant Vd2 of the second lens and the Abbe constant Vd4 of the fourth lens are both greater than 68 and less than 75.

[0017] In some embodiments, the field of view FOV of the optical system satisfies the following conditions:

[0018] 158°≤FOV≤161°.

[0019] In some embodiments, the effective focal length f of the optical system satisfies the following condition:

[0020] 2.85mm≤f≤3.05mm.

[0021] In some embodiments, the total optical length TTL of the optical system satisfies the following conditions:

[0022] 22.5mm≤TTL≤23.5mm.

[0023] In some embodiments, the first lens is meniscus-shaped and has a negative optical power;

[0024] The second lens is biconcave, with a large concave surface on the object side and a small concave surface with a platform on the image side, and its optical power is negative;

[0025] The third 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 fourth lens is plano-convex, with a flat surface on the object side and a convex surface on the image side, and its optical power is negative;

[0027] The fifth lens is of a concave-convex type, with a concave surface on the object side and a convex surface on the image side, and its optical power is positive;

[0028] 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 positive;

[0029] The seventh lens is meniscus type, with a convex surface on the object side and a concave surface on the image side, and its optical power is positive.

[0030] In some embodiments, the aperture stop is disposed between the third lens and the fourth lens.

[0031] In summary, the utility model has the following beneficial effects:

[0032] Ultra-wide-angle field of view 158°≤FOV≤161°: covers almost the entire vehicle surroundings, reduces blind spots, provides the driver with a comprehensive field of view, and enhances driving safety.

[0033] Large aperture: The aperture of this optical system is 1.8, which can allow more light to enter, enhance the imaging ability in low-light environments, and improve the overall brightness of the picture.

[0034] Ultra-clear shooting: meets 8-megapixel high-quality shooting requirements and can present high-resolution and high-brightness picture effects.

[0035] The resolution remains basically unchanged in high and low temperature environments: In environments with large temperature changes, such as direct sunlight or cold weather, the optical system can still maintain stable imaging performance and will not cause image quality degradation due to temperature changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the lens of the utility model;

[0037] Figure 2 This is the MTF analysis diagram of the utility model;

[0038] Figure 3 This is the defocus curve diagram of the utility model at 20°C;

[0039] Figure 4 This is the defocus curve diagram of the utility model at -40°C;

[0040] Figure 5 This is the defocus curve diagram of the utility model at 85°C;

[0041] Figure 6 It is the field curvature diagram of the present utility model;

[0042] Figure 7 is the distortion diagram of the utility model;

[0043] Figure 8 This is a relative illumination diagram of the present utility model.

[0044] In the figure: E1: first lens; E2: second lens; E3: third lens; STO (Stop): aperture; E4: fourth lens; E5: fifth lens; E6: sixth lens; E7: seventh lens; IR (Infrared Filter): filter; CG (Coverglass): protective glass; IMA (Image Surface): image surface;

[0045] 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; S8: the side of the fourth lens facing the object side; S9: the side where the fourth lens and the fifth lens are attached to each other; S10: the side of the fifth lens facing the image side; S11: the side of the sixth lens facing the object side; S12: the side of the sixth lens facing the image side; S13: the side of the seventh lens facing the object side; S14: the side of the seventh lens facing the image side. DETAILED DESCRIPTION

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] like Figure 1 As shown, this embodiment provides a wide-angle ultra-clear DVR optical lens imaging system, which includes, along the optical axis from the object plane to the image plane, a first lens, a second lens, a third lens, an aperture, a fourth lens, a fifth lens, a sixth lens, a seventh lens, a filter, a protective glass and an image plane;

[0051] The object side of the first lens is convex, and the image side is concave;

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

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

[0054] The fourth lens has a flat surface on its object side and a convex surface on its image side;

[0055] The fifth lens has a concave object surface and a convex image surface;

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

[0057] The seventh lens has a convex object side and a concave image side;

[0058] The fourth lens and the fifth lens form a cemented lens;

[0059] And the following relationship is satisfied:

[0060] 1.58<Nd1<1.65; 1.44<Nd2<1.52; 1.91<Nd3<1.99; 1.53<N d4<1.61; 1.9<Nd5<1.98; 1.55<Nd6<1.63; 1.73<Nd7<1.8;

[0061] Among them, Nd1 is the refractive index of the first lens, Nd2 is the refractive index of the second lens, Nd3 is the refractive index of the third lens, Nd4 is the refractive index of the fourth lens, Nd5 is the refractive index of the fifth lens, Nd6 is the refractive index of the sixth lens, and Nd7 is the refractive index of the seventh lens.

[0062] As an improvement, the Abbe constant Vd2 of the second lens and the Abbe constant Vd4 of the fourth lens are both greater than 68 and less than 75.

[0063] As an improvement, the field of view FOV of the optical system satisfies the following conditions:

[0064] 158°≤FOV≤161°.

[0065] As an improvement, the effective focal length f of the optical system satisfies the following conditions:

[0066] 2.85mm≤f≤3.05mm.

[0067] As an improvement, the total optical length TTL of the optical system meets the following conditions:

[0068] 22.5mm≤TTL≤23.5mm.

[0069] As an improvement, the first lens is meniscus-shaped and has a negative optical power;

[0070] The second lens is biconcave, with a large concave surface on the object side and a small concave surface with a platform on the image side, and its optical power is negative;

[0071] The third 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 fourth lens is plano-convex, with a flat surface on the object side and a convex surface on the image side, and its optical power is negative;

[0073] The fifth lens is of a concave-convex type, with a concave surface on the object side and a convex surface on the image side, and its optical power is positive;

[0074] 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 positive;

[0075] The seventh lens is meniscus type, with a convex surface on the object side and a concave surface on the image side, and its optical power is positive.

[0076] As an improvement, the aperture stop is arranged between the third lens and the fourth lens.

[0077] In the embodiment of this patent, when the working distance is infinity, the total focal length of the lens is f=2.97mm, FNO=1.8, the field of view angle FOV=161°, the total optical length TTL is 23mm, and the maximum image circle is 7mm.

[0078] The parameters of the lens group are listed in Table 1:

[0079]

[0080] Table 1

[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; 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 45%, and clear imaging can still be achieved under cloudy days and low-light conditions at night, fully meeting the market's technical needs.

[0083] 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. A wide-angle ultra-clear DVR optical lens imaging system, characterized by: The optical axis includes, from the object plane to the image plane, a first lens, a second lens, a third lens, an aperture, a fourth lens, 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 concave, and the image side is concave; The object side of the third lens is convex, and the image side is convex; The fourth lens has a flat surface on its object side and a convex surface on its image side; The fifth lens has a concave object surface and a convex image surface; The sixth lens has a convex surface on its object side and a convex surface on its image side; The seventh lens has a convex object side and a concave image side; The fourth lens and the fifth lens form a cemented lens; And the following relationship is satisfied: 1.58<Nd1<1.65; 1.44<Nd2<1.52; 1.91<Nd3<1.99; 1.53<N d4<1.61; 1.9<Nd5<1.98; 1.55<Nd6<1.63; 1.73<Nd7<1.8; Among them, Nd1 is the refractive index of the first lens, Nd2 is the refractive index of the second lens, Nd3 is the refractive index of the third lens, Nd4 is the refractive index of the fourth lens, Nd5 is the refractive index of the fifth lens, Nd6 is the refractive index of the sixth lens, and Nd7 is the refractive index of the seventh lens.

2. The wide-angle ultra-high definition DVR optical lens imaging system according to claim 1, characterized in that: The Abbe constant Vd2 of the second lens and the Abbe constant Vd4 of the fourth lens are both greater than 68 and less than 75.

3. The wide-angle ultra-high-definition DVR optical lens imaging system according to claim 1, characterized in that: The field of view FOV of the optical system meets the following conditions: 158°≤FOV≤161°.

4. The wide-angle ultra-high definition DVR optical lens imaging system according to claim 1, characterized in that: The effective focal length f of the optical system satisfies the following conditions: 2.85mm≤f≤3.05mm.

5. The wide-angle ultra-high definition DVR optical lens imaging system according to claim 1, characterized in that: The total optical length TTL of the optical system meets the following conditions: 22.5mm≤TTL≤23.5mm.

6. The wide-angle ultra-high definition DVR optical lens imaging system according to claim 1, characterized in that: The first lens is meniscus-shaped and has negative focal power; The second lens is biconcave, with a large concave surface on the object side and a small concave surface with a platform on the image side, and its optical power is negative; The third 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 fourth lens is plano-convex, with a flat surface on the object side and a convex surface on the image side, and its optical power is negative; The fifth lens is of a concave-convex type, with a concave surface on the object side and a 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 positive; The seventh lens is meniscus type, with a convex surface on the object side and a concave surface on the image side, and its optical power is positive.

7. The wide-angle ultra-high definition DVR optical lens imaging system according to claim 1, characterized in that: The aperture is arranged between the third lens and the fourth lens.

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