Aspherical super-wide-angle optical imaging system

Abstract

The application provides a non-spherical surface super-wide-angle optical imaging system, which comprises two parts of an optical lens and a photoelectric conversion device. The lens part comprises seven optical lenses arranged in the order of a concave lens, a concave lens, a convex lens, a concave lens, a convex lens, a convex lens and a concave lens from the light incidence direction; the focal length of the lens is 0.5 mm, the F number is 0.8, the working wavelength is in the visible light band, the field of view is 156 degrees, and the total optical length of the system is 20 mm; the seven lenses are arranged and installed in the order from the object direction, the shape cooperation between the seven lenses can make the field of view angle of the lens reach 156 degrees, and the purpose of expanding the field of view angle of the lens is achieved. The lens can be used as a vehicle-mounted imaging system in cooperation with the photoelectric conversion device; in the design process of the lens, the aspheric surface technology is adopted, five of the seven lenses are aspheric lenses, all aberrations are corrected in the optimization process, and finally the lens has the advantages of super-wide-angle, large relative aperture, miniaturization, light weight and good image quality.

Description

Technical Field

[0001] This invention relates to the field of optical design technology, and in particular to an aspherical ultra-wide-angle optical imaging system. Background Technology

[0002] A vehicle-mounted camera is a camera used in vehicles such as cars, buses, and taxis. It can record images and videos of the vehicle in motion in real time and provide evidence or records when needed.

[0003] A wide-angle lens, also known as a short-angle lens, is a type of auxiliary lens for photography. Its focal length is significantly smaller than the image circle diameter (the diagonal length of the film), with a field of view of approximately 60 to 84 degrees and a relatively small aperture. Wide-angle lenses are used to shoot wide-ranging scenes at close range, making the foreground more prominent. The depth of field is significantly greater than that of standard or telephoto lenses, resulting in a strong sense of depth. They are suitable for indoor close-up shooting and for capturing landscapes, architecture, crowds, etc. When using a wide-angle lens for close-up shots, the foreground is exaggerated, resulting in more severe perspective distortion. Images shot with a wide-angle lens can highlight the central subject and foreground while having a wide background. It allows capturing more objects in a relatively small environment, and at the same shooting distance, the resulting scene appears smaller than when shooting with a standard lens. When shooting close-up objects, perspective distortion occurs, and the perceived distance between foreground and background objects increases. Due to its long depth of field, it is easy to capture both near and far objects in sharp focus. Wide-angle lenses can be used as in-vehicle cameras to provide drivers with real-time monitoring images and video evidence for handling traffic accidents. Wide-angle lenses can also provide more comprehensive data for autonomous driving technology. However, the field of view of conventional in-vehicle cameras is generally 80 to 120 degrees, which is still insufficient to fully observe the external environment in many scenarios and does not meet the growing demand for large field of view in in-vehicle cameras.

[0004] To overcome the above-mentioned shortcomings, an aspherical ultra-wide-angle optical imaging system was designed. Summary of the Invention

[0005] In view of this, embodiments of the present invention provide an aspherical ultra-wide-angle optical imaging system, which can be mainly used as an in-vehicle optical imaging system. The system's lens employs aspherical technology to simplify the optical path structure, achieving miniaturization and weight reduction. Through reasonable lens design, ultra-wide-angle imaging is achieved, improving system performance. The lens design fully considers various application scenarios, selecting a field of view of 156°, and rigorously correcting and controlling various aberrations. The final lens possesses advantages such as ultra-wide angle, large relative aperture, miniaturization, weight reduction, and excellent image quality.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions.

[0007] This invention provides an aspherical ultra-wide-angle optical imaging system, whose lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged coaxially along the light incident direction, which are respectively a concave lens, a concave lens, a convex lens, a concave lens, a convex lens, a convex lens, and a concave lens; the first lens is made of NSK16_SCHOTT material, with a light transmittance of 11.5mm < aperture diameter < 12.0mm and a thickness of 1.0mm < 1.5mm; the second lens is made of ZBAF51_CDGM material, with a light transmittance of 4.5mm < aperture diameter < 5.0mm and a thickness of 2.0mm < 2.5mm; the third lens is made of HZBAF21_CDGM material, with a light transmittance of 4.5mm < aperture diameter < 5.0mm and a thickness of 2.0mm < 2.5mm. The first seven lenses are made of SF4_SCHOTT, with a light-transmitting aperture of 5.0mm and a thickness of 2.0mm and 1.0mm respectively. The second and third lenses are made of SF4_SCHOTT, with a light-transmitting aperture of 3.0mm and a thickness of 2.5mm and 1.5mm respectively. The fourth lens is made of HZK7_CDGM, with a light-transmitting aperture of 2.5mm and a thickness of 3.0mm and 1.5mm respectively. The sixth lens is made of NPSK3_SCHOTT, with a light-transmitting aperture of 3.0mm and a thickness of 2.0mm and 2.5mm respectively. The seventh lens is made of SF4_SCHOTT, with a light-transmitting aperture of 3.0mm and a thickness of 3.5mm and 0.5mm respectively. These seven lenses achieve good chromatic aberration and aberration correction effects through material combinations.

[0008] Optionally, the first lens has a light-transmitting aperture of 11.90 mm and a thickness of 1.27 mm; the second lens has a light-transmitting aperture of 4.97 mm and a thickness of 2.40 mm; the third lens has a light-transmitting aperture of 4.85 mm and a thickness of 2.31 mm; the fourth lens has a light-transmitting aperture of 2.13 mm and a thickness of 0.60 mm; the fifth lens has a light-transmitting aperture of 2.62 mm and a thickness of 1.83 mm; the sixth lens has a light-transmitting aperture of 3.28 mm and a thickness of 2.11 mm; and the seventh lens has a light-transmitting aperture of 3.08 mm and a thickness of 0.73 mm.

[0009] Optionally, the fourth lens and the fifth lens form a cemented lens.

[0010] Optionally, the distance between the center of the light exit surface of the seventh lens and the image plane is 1.5 mm.

[0011] Optionally, the aspherical ultra-wide-angle optical imaging lens has dimensions of φ11.9×20mm.

[0012] Optionally, the optical system of the aspherical ultra-wide-angle optical imaging lens has a focal length of 0.5mm and an F-number of 0.8.

[0013] Optionally, the spectral range of the aspherical ultra-wide-angle optical imaging lens is 480nm~620nm.

[0014] Optionally, the aspherical ultra-wide-angle optical imaging lens has a full field of view of 156°.

[0015] As can be seen from the above technical solutions, the embodiments of the present invention have the following advantages:

[0016] 1. The aspherical ultra-wide-angle optical imaging system simplifies the optical path structure through aspherical technology. The optical system consists of only seven lenses, with a total system length of 20mm and an optical aperture of 11.9mm, meeting the requirements of miniaturization and lightweight design.

[0017] 2. The aspherical ultra-wide-angle optical imaging system has a full field of view of 156°, which ensures perfect monitoring of the scene in front of the vehicle and achieves the purpose of expanding the lens's field of view. Attached Figure Description

[0018] Figure 1 This is a structural diagram of the optical system of the aspherical ultra-wide-angle optical imaging lens of the present invention;

[0019] Figure 2 This is a dot diagram of the aspherical ultra-wide-angle optical imaging lens of the present invention;

[0020] Figure 3 This is the optical modulation transfer function of the aspherical ultra-wide-angle optical imaging lens of the present invention;

[0021] Reference numerals in the attached diagram: 1-First lens; 2-Second lens; 3-Third lens; 4-Fourth lens; 5-Fifth lens; 6-Sixth lens; 7-Seventh lens. Detailed Implementation

[0022] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort should fall within the scope of protection of the present invention.

[0023] Please refer to Figure 1The diagram shows the optical system structure of this invention. This aspherical ultra-wide-angle optical imaging system includes seven lenses arranged in a concave-convex-concave-convex ... <2.5mm; the material of the fourth lens 4 is SF4_SCHOTT, 2.0mm < aperture diameter < 2.5mm, 0.5mm < thickness < 1.0mm; the material of the fifth lens 5 is HZK7_CDGM, 2.5mm < aperture diameter < 3.0mm, 1.5mm < thickness < 2.0mm; the material of the sixth lens 6 is NPSK3_SCHOTT, 3.0mm < aperture diameter < 3.5mm, 2.0mm < thickness < 2.5mm; the material of the seventh lens 7 is SF4_SCHOTT, 3.0mm < aperture diameter < 3.5mm, 0.5mm < thickness < 1.0mm.

[0024] In one embodiment, the first lens 1 has an aperture of 11.90 mm and a thickness of 1.27 mm; the second lens 2 has an aperture of 4.97 mm and a thickness of 2.40 mm; the third lens 3 has an aperture of 4.85 mm and a thickness of 2.31 mm; the fourth lens 4 has an aperture of 2.13 mm and a thickness of 0.60 mm; the fifth lens 5 has an aperture of 2.62 mm and a thickness of 1.83 mm; the sixth lens 6 has an aperture of 3.28 mm and a thickness of 2.11 mm; and the seventh lens 7 has an aperture of 3.08 mm and a thickness of 0.73 mm. This results in an aspherical ultra-wide-angle optical imaging system with a focal length of 0.5 mm, an F-number of 0.8, a field of view of 156°, and dimensions of φ11.9 × 20 mm. The final lens possesses advantages such as ultra-wide angle, large relative aperture, miniaturization, lightweight design, and good image quality.

[0025] In one embodiment, the fourth lens and the fifth lens form a cemented lens, and the combination of optical materials of the two lenses ensures that the chromatic aberration of the optical system is well corrected.

[0026] In one embodiment, the aspherical ultra-wide-angle optical imaging system has a full field of view of 156°, making it suitable for applications such as driving recording and reversing camera monitoring.

[0027] Please refer to Figure 2 The figure shows a dot plot of the optical system of the aspherical ultra-wide-angle optical imaging system of the present invention. It can be seen from the figure that the RMS of the blur spots corresponding to each field of view is basically less than 1.5 μm, indicating that the aberrations of the optical system are well corrected overall.

[0028] Please refer to Figure 3 , where MTF is the optical modulation transfer function of the aspherical ultra-wide-angle optical imaging system of the present invention. As can be seen from the figure, within the spatial frequency range of 50 cycles / mm, the MTF of each field of view is basically higher than 0.2, indicating that the optical system has good imaging quality.

[0029] The following shows the lens data for the aspherical ultra-wide-angle optical imaging system. Table 1 shows the surface type and related optical parameters of each lens in the optical lens.

[0030] Table 1

[0031]

[0032] The formula for representing aspherical surface shape used in the embodiments of this invention is as follows:

[0033]

[0034] Where z is the sag of the aspherical surface at a position of radius r along the optical axis, from the vertex of the aspherical surface; c is the paraxial curvature of the aspherical surface; and k is the conic coefficient. i is the correction coefficient of the i-th order for the aspherical surface.

[0035] Table 2 shows the coefficients of each aspherical higher-order term in this embodiment.

[0036] Table 2

[0037]

[0038] The aspherical ultra-wide-angle optical imaging system described in this invention has a focal length of 0.5mm, an F-number of 0.8, and operates in the visible light band. The total optical length of the system is 20mm. The shape coordination between the seven lenses enables the lens field of view to reach 156°, thus expanding the lens's viewing angle. This lens is primarily designed for driving recording and in-vehicle applications, but can also be used in similar non-vehicle scenarios. The lens design employs aspherical technology to correct all types of aberrations, giving it the advantages of ultra-wide angle, large relative aperture, miniaturization, lightweight design, and excellent image quality.

[0039] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. An aspherical ultra-wide-angle optical imaging system, comprising an optical lens and a photoelectric conversion device, wherein the lens part is characterized by comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens arranged coaxially along the incident direction of light. The first lens is made of NSK16_SCHOTT, with a convex object side and a concave image side. It has a light-transmitting aperture of 11.5mm and a thickness of 1.0mm, and is a positive optical power. The second lens is made of ZBAF51_CDGM material, with a concave object side and a convex image side. It has a light-transmitting aperture of 4.5mm and a thickness of 2.0mm, and is a negative optical power. The third lens is made of HZBAF21_CDGM material, with a convex object side and a concave image side. It has a light-transmitting aperture of 4.5mm and a thickness of 2.0mm, and is a positive optical power. The fourth lens is made of SF4_SCHOTT, with a convex object side and a concave image side. It has a light-transmitting aperture of 2.0 mm and a thickness of 0.5 mm, and is a negative optical power. The fifth lens is made of HZK7_CDGM material, with a convex object side and a convex image side. It has a light-transmitting aperture of 2.5mm and a thickness of 1.5mm, which is positive optical power. The material of the sixth lens is NPSK3_SCHOTT, with a convex object side and a convex image side. The aperture diameter is 3.0mm < 3.5mm, the thickness is 2.0mm < 2.5mm, and the optical power is positive. The seventh lens is made of SF4_SCHOTT, with a concave object side and a concave image side. It has a light-transmitting aperture of 3.0 mm and a thickness of 0.5 mm, and is a negative optical power.

2. The aspherical ultra-wide-angle optical imaging system as described in claim 1, wherein the lens portion is characterized by: The first lens has a light-transmitting aperture of 11.90 mm and a thickness of 1.27 mm; The second lens has a light-transmitting aperture of 4.97 mm and a thickness of 2.40 mm. The third lens has a light-transmitting aperture of 4.85 mm and a thickness of 2.31 mm. The fourth lens has a light-transmitting aperture of 2.13 mm and a thickness of 0.60 mm. The fifth lens has a light-transmitting aperture of 2.62 mm and a thickness of 1.83 mm. The sixth lens has a light-transmitting aperture of 3.28 mm and a thickness of 2.11 mm. The seventh lens has a light-transmitting aperture of 3.08 mm and a thickness of 0.73 mm.

3. The aspherical ultra-wide-angle optical imaging system as described in claim 1, wherein the lens portion is characterized in that: the fourth lens and the fifth lens form a cemented lens.

4. The aspherical ultra-wide-angle optical imaging system as described in claim 1, wherein the lens portion is characterized in that the distance between the center of the light emitting surface of the seventh lens and the image plane is 1.5 mm.

5. The aspherical ultra-wide-angle optical imaging system as described in claim 1, wherein the lens portion is characterized in that: the external dimensions of the aspherical ultra-wide-angle optical imaging lens are φ11.9×20mm.

6. The aspherical ultra-wide-angle optical imaging system as described in claim 1, wherein the lens portion is characterized in that: the optical system focal length of the aspherical ultra-wide-angle optical imaging lens is 0.5mm and the F-number is 0.

8.

7. The aspherical ultra-wide-angle optical imaging system as described in claim 1, wherein the lens portion is characterized in that the full field of view of the aspherical ultra-wide-angle optical imaging lens is 156°.

8. The aspherical ultra-wide-angle optical imaging system as described in claim 1, wherein the photoelectric conversion device is characterized by employing a CCD or CMOS.

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