A vehicle-mounted surround view optical system with thermal drift stabilization for ultra-large target surface

Abstract

An embodiment of the present invention discloses an ultra-large target surface thermal drift-stabilized vehicle-mounted surround-view optical system, specifically relating to the field of vehicle-mounted surround-view optical systems. By adopting an optical system composed of lenses with a specific structural shape and reasonable optical focal length distribution, the full image height can reach 9.1mm. Combined with the large aperture of the lens, it can match a 1 / 1.55" large target surface chip, presenting a perfect picture with low edge illumination to the greatest extent, supporting 5 million pixels, and meeting people's high requirements for imaging effects. In addition, the structural shape of the optical lens system provided by the present invention, the Abbe coefficient and other parameters of the optical glass material are better matched with the imaging conditions, and the two groups of glass-cemented lenses effectively reduce the spherical aberration, coma, astigmatism, field curvature, position chromatic aberration, and magnification chromatic aberration of the entire lens system, ensuring uniform imaging on the entire image surface. The all-glass structure also maintains a stable defocus curve under high and low temperature conditions, thereby achieving temperature resistance of the entire optical lens system.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of vehicle-mounted surround-view optical systems, and in particular to a vehicle-mounted surround-view optical system with an ultra-large target surface and thermal drift stabilization. Background Art

[0002] The initial applications of in-vehicle optical systems were for reverse assist and driving recording. With the expansion of their functions and applications, different application scenarios have emerged, including side view, surround view, electronic rearview, and in-cabin monitoring. In-vehicle surround view optical systems can assist drivers in perceiving their surroundings, such as the relative position and distance of surrounding obstacles, and lane line detection during driving, effectively avoiding safety hazards in blind spots during driving. As an important component of intelligent assisted driving systems, in-vehicle surround view optical systems are increasingly in demand, and the market's technical requirements for surround view optical systems are also becoming increasingly stringent. However, existing technologies generally suffer from issues such as target surfaces smaller than 6mm, low edge brightness when shooting at wide angles, a narrow field of view, and poor imaging quality in high or low temperature environments. Summary of the Invention

[0003] To this end, an embodiment of the present invention provides an ultra-large target surface thermal drift-stabilized vehicle-mounted surround-view optical system. By adopting an optical system composed of lenses with a specific structural shape and a reasonable optical focal length distribution, the full image height can reach 9.1mm. Combined with the large aperture of the lens, it can match a 1 / 1.55" large target surface chip, presenting a perfect picture with low edge illumination to the greatest extent, and can support 5 million pixels, which can meet people's high requirements for imaging effects. In addition, the structural shape of the optical lens system provided by the present invention and the Abbe coefficient and other parameters of the optical glass material are well matched with the imaging conditions. The two sets of glass cemented lenses effectively reduce the spherical aberration, coma, astigmatism, field curvature, position chromatic aberration, and magnification chromatic aberration of the entire lens system, ensuring uniform imaging across the entire image surface. The all-glass structure also maintains a stable defocus curve under high and low temperature conditions, thereby achieving temperature resistance of the entire optical lens system.

[0004] In order to achieve the above-mentioned purpose, the embodiment of the present invention provides the following technical solutions: Figure 1 As shown, a specific embodiment of the present invention provides an optical system, which includes, from the object side to the image side along the optical axis, in sequence: a first meniscus lens with negative optical power, a second biconcave lens with negative optical power, a third cemented lens group with positive optical power, which includes a third plano-convex lens with positive optical power and a fourth meniscus lens with positive optical power, a fifth meniscus lens with positive optical power, a sixth cemented lens group with positive optical power, which includes a sixth biconvex lens with negative optical power and a seventh meniscus lens with positive optical power, an eighth plano-convex lens with positive optical power, a filter and an image plane; wherein the surface of the first meniscus lens facing the object side is a convex surface.

[0005] An optical system provided by an embodiment of the present invention, by adopting an optical system composed of lenses with a specific structural shape and a reasonable optical power distribution, can achieve ultra-wide angle while achieving a large aperture. At the same time, the full image height can reach 9.1mm. In combination with the large aperture of the lens, it can match a 1 / 1.55" large target chip, presenting a perfect picture with low illumination at the edge to the greatest extent, and can support 5 million pixels, which can meet people's high requirements for imaging effects. In addition, the structural shape of the optical lens system provided by the present invention, the Abbe coefficient and other parameters of the optical glass material are well matched with the imaging conditions. The two sets of glass cemented lenses effectively reduce the spherical aberration, coma, astigmatism, field curvature, position chromatic aberration, and magnification chromatic aberration of the entire lens system, ensuring uniform imaging across the entire image plane. The all-glass structure also maintains a stable defocus curve under high and low temperature conditions, achieving temperature resistance of the entire optical lens system and ensuring resolution requirements.

[0006] In specific implementation, in the above optical system provided by the embodiment of the present invention, if Figure 1 As shown, the third cemented lens group includes: a third plano-convex lens with positive optical power, with the convex surface facing the image measurement and the flat or slightly convex surface facing the object measurement; a fourth meniscus lens with positive optical power, with the convex surface facing the image measurement and the concave surface facing the object measurement; the sixth cemented lens group includes: a sixth biconvex lens with negative optical power, with the large convex surface facing the image measurement and the slightly convex surface facing the object measurement; and a seventh meniscus lens with positive optical power, with the convex surface facing the image measurement and the concave surface facing the object measurement.

[0007] Furthermore, in the above optical system provided by an embodiment of the present invention, the ratio of the focal lengths of the first to eighth lenses to the focal length of the lens satisfies the following set relationship:

[0008] 4.9<|f1 / f|<5.7, 2.0<|f2 / f|<2.6, 8.3<|f3 / f|<9.3, 5.1<|f4 / f|<5.9, 4.7<|f5 / f|<5.5, 3.5<|f6 / f|<4.0, 15<|f7 / f|<15.7, 4.5<|f8 / f|<5.2; wherein f1 represents the effective focal length of the first meniscus lens, f2 represents the effective focal length of the second biconcave lens, f3 represents the effective focal length of the third plano-convex lens, f4 represents the effective focal length of the fourth meniscus lens, f5 represents the effective focal length of the fifth meniscus lens, f6 represents the effective focal length of the sixth biconvex lens, f7 represents the effective focal length of the seventh meniscus lens, f8 represents the effective focal length of the eighth plano-convex lens, and f represents the effective focal length of the optical system.

[0009] Furthermore, in a specific implementation, in the above optical system provided by an embodiment of the present invention, the refractive indices of the first to eighth lenses satisfy the following conditions:

[0010] 1.4 <n1<2.0;1.4<n2<2.0;1.7<n3<2.2;1.4<n4<1.9;1.5<n5<2.2;1.3<n6<1.8;1.7<n7<2.3;1.4<n8<2.0;

[0011] Among them, n1 is the refractive index of the first meniscus lens, n2 is the refractive index of the second biconcave lens, n3 is the refractive index of the third plano-convex lens, n4 is the refractive index of the fourth meniscus lens, n5 is the refractive index of the fifth meniscus lens, n6 is the refractive index of the sixth biconvex lens, n7 is the refractive index of the seventh meniscus lens, and n8 is the refractive index of the eighth plano-convex lens.

[0012] Furthermore, in the above optical system provided by an embodiment of the present invention, the Abbe coefficients of the first meniscus lens, the second biconcave lens, and the eighth plano-convex lens are all equal to 49.6.

[0013] Furthermore, in the above optical system provided by an embodiment of the present invention, the total optical length TTL of the optical system satisfies the following condition: 34.5 mm ≤ TTL ≤ 36 mm.

[0014] Furthermore, in the above optical system provided by the embodiment of the present invention, the full image height IH of the optical system satisfies the following condition: IH ≥ 9.1 mm.

[0015] Furthermore, in the above optical system provided by an embodiment of the present invention, the effective focal length f of the optical system satisfies the following condition: 2.8 mm ≤ f ≤ 3 mm.

[0016] Furthermore, in the above-mentioned optical system provided by an embodiment of the present invention, the third cemented lens group includes: a third plano-convex lens with positive optical focal power and a fourth meniscus lens with positive optical focal power; the sixth cemented lens group includes: a sixth biconvex lens with negative optical focal power and a seventh meniscus lens with positive optical focal power.

[0017] The embodiments of the present invention have the following advantages:

[0018] 1. It achieves both ultra-wide angle and large aperture, with an F No. of 2.1 and a maximum field of view of 196 degrees;

[0019] 2. The full image height can reach 9.1mm. With the large aperture of the lens, it can match the 1 / 1.55" large image chip, presenting the perfect picture with low illumination at the edge to the greatest extent, and can support 5 million pixels;

[0020] 3. The all-glass structure has good temperature resistance. The defocus curve is stable at high temperatures of 85 degrees and low temperatures of -40 degrees, ensuring the required resolution. Two sets of glass cemented lenses effectively reduce the spherical aberration, coma, astigmatism, field curvature, position chromatic aberration, and magnification chromatic aberration of the entire lens system, ensuring uniform imaging across the entire image surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other implementation drawings based on the provided drawings without inventive effort.

[0022] The structures, proportions, sizes, etc. illustrated in this specification are intended only to complement the contents disclosed herein and to facilitate understanding and reading by persons familiar with the art. They are not intended to limit the conditions under which the present invention may be implemented and therefore have no substantive technical significance. Any structural modifications, changes in proportions, or adjustments in sizes, without affecting the efficacy and objectives of the present invention, shall still fall within the scope of the technical contents disclosed herein.

[0023] Figure 1 Schematic diagram of a lens according to an embodiment of the present invention;

[0024] Figure 2 This is a defocus curve diagram of 125lp / mm at 20°C according to an embodiment of the present invention;

[0025] Figure 3 This is a defocus curve diagram of 125lp / mm at 85°C according to an embodiment of the present invention;

[0026] Figure 4 This is a defocus curve diagram of 125lp / mm at -40°C according to an embodiment of the present invention;

[0027] Figure 5 This is a 100lp / mm MTF analysis diagram at 20°C of an embodiment of the present invention;

[0028] Figure 6 This is a 100lp / mm MTF analysis diagram at 85°C of an embodiment of the present invention;

[0029] Figure 7 This is a 100lp / mm MTF analysis diagram at -40°C of an embodiment of the present invention;

[0030] Figure 8 A field curvature diagram according to an embodiment of the present invention;

[0031] Figure 9This is an F-THETA distortion diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0032] The following describes an embodiment of an optical system according to an embodiment of the present invention. It should be noted that the data listed in Table 1 below are preferred data for the present invention and are not intended to limit the present invention. Any person skilled in the art, after referring to the present invention, may make appropriate changes to the parameters or settings, and such changes will still fall within the scope of the present invention.

[0033] surf Radius Thickness Index ABB EFL-E OBJ 50000.000 3000.000 1 22.733 1.100 1.77 49.6 -15.78 2 7.657 5.972 3 -528.909 1.200 1.77 49.6 -6.75 4 5.289 3.768 5 -366.600 5.000 1.9 31.3 25.95 6 -5.687 0.750 1.67 32.2 16.21 7 -31.891 0.100 8 6.295 2.459 1.83 42.7 15.07 9 10.287 1.568 STO Infinity 1.345 11 32.21 2.335 1.59 68.6 -10.96 12 -3.2 1.85 1.95 18.0 45.42 13 -7.835 0.476 14 11.215 2.715 1.77 49.6 14.44 15 1.000E+18 1.000 16 Infinity 0.800 1.52 64.2 17 Infinity 3.100 IMA Infinity 0.000

[0034] Table 1

[0035] Specifically, the R value and thickness of each lens surface in this embodiment are shown in Table 1.

[0036] Among them, the optical system provided in Table 1 has an effective focal length of 2.95 mm, a clear aperture of F / 2.1, a total length of the optical system of 35.5 mm, an image plane size of 9.1 mm, and a field of view 2w of 196 degrees. In Table 1, mirror numbers 1 and 2 represent the two mirror surfaces of lens 1 along the direction of incident light, mirror numbers 3 and 4 represent the two mirror surfaces of lens 2 along the direction of incident light, mirror number 5 represents the mirror surface of lens 3 facing the object side, mirror number 6 represents the cemented surface of lens 3 and lens 4, mirror number 7 represents the mirror surface of lens 4 facing the image side, mirror numbers 8 and 9 represent the two mirror surfaces of lens 5 along the direction of incident light, mirror number 11 represents the mirror surface of lens 6 facing the object side, mirror number 12 represents the cemented surface of lens 6 and lens 7, mirror number 13 represents the mirror surface of lens 7 facing the image side, and mirror numbers 14 and 15 represent the two mirror surfaces of lens 8 along the direction of incident light.

[0037] 1. In this embodiment of the present invention, the ratio of the focal length of the first to eighth lenses to the focal length of the lens satisfies the following set relationship:

[0038] 4.9<|f1 / f|<5.7, 2.0<|f2 / f|<2.6, 8.3<|f3 / f|<9.3, 5.1<|f4 / f|<5.9, 4.7<|f5 / f|<5.5, 3.5<|f6 / f|<4.0, 15<|f7 / f|<15.7, 4.5<|f8 / f|<5.2; wherein f1 represents the effective focal length of the first meniscus lens, f2 represents the effective focal length of the second biconcave lens, f3 represents the effective focal length of the third plano-convex lens, f4 represents the effective focal length of the fourth meniscus lens, f5 represents the effective focal length of the fifth meniscus lens, f6 represents the effective focal length of the sixth biconvex lens, f7 represents the effective focal length of the seventh meniscus lens, f8 represents the effective focal length of the eighth plano-convex lens, and f represents the effective focal length of the optical system.

[0039] 2. The refractive indices of the first through eighth lenses of this embodiment of the present invention satisfy the following conditions:

[0040] 1.4 <n1<2.0;1.4<n2<2.0;1.7<n3<2.2;1.4<n4<1.9;1.5<n5<2.2;1.3<n6<1.8;1.7<n7<2.3;1.4<n8<2.0;

[0041] Among them, n1 is the refractive index of the first meniscus lens, n2 is the refractive index of the second biconcave lens, n3 is the refractive index of the third plano-convex lens, n4 is the refractive index of the fourth meniscus lens, n5 is the refractive index of the fifth meniscus lens, n6 is the refractive index of the sixth biconvex lens, n7 is the refractive index of the seventh meniscus lens, and n8 is the refractive index of the eighth plano-convex lens.

[0042] 3. In the embodiment of the present invention, the Abbe coefficients of the first meniscus lens, the second biconcave lens, and the eighth plano-convex lens are all equal to 49.6.

[0043] 4. The total optical length TTL of the optical system described in the embodiment of the present invention satisfies the following condition: 34.5 mm ≤ TTL ≤ 36 mm.

[0044] 5. The full image height IH of the optical system described in the embodiment of the present invention satisfies the following condition: IH ≥ 9.1 mm.

[0045] 6. The effective focal length f of the optical system described in the embodiment of the present invention satisfies the following condition: 2.8 mm ≤ f ≤ 3 mm.

[0046] 7. The third cemented lens group described in this embodiment of the present invention includes: a third plano-convex lens with positive optical power and a fourth meniscus lens with positive optical power; the sixth cemented lens group includes: a sixth biconvex lens with negative optical power and a seventh meniscus lens with positive optical power.

[0047] The above embodiments of the present invention all meet the requirements.

[0048] In an embodiment of the present invention, Figure 5 The modulation transfer function (MTF) curve for the visible light band represents the comprehensive resolution capability of the optical system. The horizontal axis represents the spatial frequency (cycles / mm), and the vertical axis represents the value of the modulation transfer function (MTF). The MTF value 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 a relatively accurate, intuitive and common way to evaluate the imaging quality of an optical system. 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. Figure 5 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 greater than 0.7, and the imaging quality is good. Figure 2 From the defocus curve, we can see that the MTF concentration of this lens is good, making it easy to focus.

[0049] The optical system provided by this specific implementation corrects various aberrations, such as spherical aberration, coma, astigmatism, field curvature, magnification chromatic aberration, position chromatic aberration, etc., thereby improving the resolution. Figure 2 and Figure 5 It can be seen that the optical lens of the embodiment of the present invention has corrected and balanced various aberrations to a relatively good level. Although the present invention has been described in detail above using a general description and specific embodiments, it will be apparent to those skilled in the art that modifications or improvements can be made based on the present invention. Therefore, such modifications or improvements made without departing from the spirit of the present invention are within the scope of protection claimed in the present invention.

Claims

1. A vehicle-mounted surround view optical system with thermal drift stabilization for an ultra-large target surface, characterized by: Along the optical axis, from the object side to the image side, the following are arranged in order: a first meniscus lens with negative optical power, with a convex surface on the object side and a concave surface on the image side; a second biconcave lens with negative optical power, with a slightly concave surface on the object side and a concave surface on the image side; a third cemented lens group with positive optical power, including a third plano-convex lens with positive optical power and a fourth meniscus lens with positive optical power; a fifth meniscus lens with positive optical power, with a convex surface on the object side and a concave surface on the image side; a sixth cemented lens group with positive optical power, including a sixth biconvex lens with negative optical power and a seventh meniscus lens with positive optical power; an eighth plano-convex lens with positive optical power, with a convex surface on the object side and a flat surface on the image side; a filter and an image plane; The ratio of the focal lengths of the first to eighth lenses to the focal length of the lens satisfies the following relationship: 4.9<|f1 / f|<5.7, 2.0<|f2 / f|<2.6, 8.3<|f3 / f|<9.3, 5.1<|f4 / f|<5.9, 4.7<|f5 / f|<5.5, 3.5<|f6 / f|<4.0, 15<|f7 / f|<15.7, 4.5<|f8 / f|<5.2; wherein f1 represents the effective focal length of the first meniscus lens, f2 represents the effective focal length of the second biconcave lens, f3 represents the effective focal length of the third plano-convex lens, f4 represents the effective focal length of the fourth meniscus lens, f5 represents the effective focal length of the fifth meniscus lens, f6 represents the effective focal length of the sixth biconvex lens, f7 represents the effective focal length of the seventh meniscus lens, f8 represents the effective focal length of the eighth plano-convex lens, and f represents the effective focal length of the optical system.

2. The ultra-large target surface thermal drift-stabilized vehicle-mounted surround view optical system according to claim 1, characterized in that: The refractive indices of the first to eighth lenses satisfy the following conditions: 1.4 <n1<2.0;1.4<n2<2.0;1.7<n3<2.2;1.4<n4<1.9;1.5<n5<2.2; 1.3 <n6<1.8;1.7<n7<2.3;1.4<n8<2.0; Among them, n1 is the refractive index of the first meniscus lens, n2 is the refractive index of the second biconcave lens, n3 is the refractive index of the third plano-convex lens, n4 is the refractive index of the fourth meniscus lens, n5 is the refractive index of the fifth meniscus lens, n6 is the refractive index of the sixth biconvex lens, n7 is the refractive index of the seventh meniscus lens, and n8 is the refractive index of the eighth plano-convex lens.

3. The ultra-large target surface thermal drift-stabilized vehicle-mounted surround view optical system according to claim 2, characterized in that: The Abbe coefficients of the first meniscus lens, the second biconcave lens, and the eighth plano-convex lens are all equal to 49.

6.

4. The ultra-large target surface thermal drift-stabilized vehicle-mounted surround view optical system according to claim 1, characterized in that: The total optical length TTL of the optical system satisfies the following condition: 34.5 mm ≤ TTL ≤ 36 mm.

5. The ultra-large target surface thermal drift stabilized vehicle-mounted surround view optical system according to claim 1, characterized in that: The total image height IH of the optical system satisfies the following condition: IH ≥ 9.1 mm.

6. The ultra-large target surface thermal drift stabilized vehicle-mounted surround view optical system according to claim 1, characterized in that: The effective focal length f of the optical system satisfies the following condition: 2.8 mm ≤ f ≤ 3 mm.

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