Wide-angle vehicle-mounted foresight fixed-focus optical lens

Abstract

The utility model relates to the technical field of optical lenses, in particular to a wide-angle vehicle-mounted foresight fixed-focus optical lens, which comprises a lens, a diaphragm, an optical filter and chip protection glass. A first lens, a second lens, a third lens, a fourth lens, a diaphragm, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, an optical filter and chip protection glass are sequentially arranged along an optical axis from an object space to an image space, according to the utility model, nine glass spherical lenses are adopted to form an eight-group nine-piece optical structure, so that the characteristics of high resolution (8MP), large aperture (FNO = 2.0), wide field angle (the field angle DFOV in the diagonal direction is greater than or equal to 72 degrees), compact structure (TTL < = 30.0 mm), large target surface (the image height phi is approximately equal to 9.6 mm), low cost and the like are realized.

Description

Technical Field

[0001] This utility model relates to the technical field of optical lenses, specifically a wide-angle automotive front-view fixed-focus optical lens. Background Technology

[0002] With the rapid development of modern automotive safety lenses and autonomous driving technology, automotive camera lenses, as one of the key sensors, play a crucial role. Wide-angle automotive forward-facing fixed-focus optical lenses, in particular, provide vehicles with a broad field of view, enabling driver assistance lenses to detect road conditions and potential obstacles earlier. Traditionally, to meet the needs of different applications, such as lane-keeping assist and automatic emergency braking, these optical lenses need to possess excellent performance.

[0003] In recent years, although various types of wide-angle automotive forward-looking fixed-focus optical lenses have appeared on the market, existing products still have some limitations. While common optical lenses can provide a wide field of view, their image clarity in the edge areas is poor. Therefore, developing a new generation of wide-angle automotive forward-looking fixed-focus optical lenses that can guarantee high-quality imaging is particularly urgent.

[0004] Based on this, this utility model designs a wide-angle vehicle-mounted forward-looking fixed-focus optical lens to solve the above problems. Utility Model Content

[0005] To achieve the above objectives, this utility model provides the following technical solution: a wide-angle automotive front-view fixed-focus optical lens, comprising a lens, an aperture stop, a filter, and a chip protective glass. From the object side to the image side, along the optical axis, a first lens, a second lens, a third lens, a fourth lens, an aperture stop, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a filter, and the chip protective glass are arranged sequentially. The seventh lens and the eighth lens form a first cemented doublet lens. All lenses are spherical glass lenses. The filter is a visible light bandpass filter. The first lens is a meniscus spherical glass lens with negative optical power; the second lens is a... The first lens is a meniscus glass spherical lens with positive optical power; the second lens is a biconcave glass spherical lens with negative optical power; the third lens is a biconvex glass spherical lens with positive optical power; the fourth lens is a meniscus glass spherical lens with positive optical power; the fifth lens is a meniscus glass spherical lens with positive optical power; the sixth lens is a meniscus glass spherical lens with positive optical power; the seventh lens is a biconvex glass spherical lens with positive optical power; the eighth lens is a biconcave glass spherical lens with negative optical power; and the ninth lens is a meniscus glass spherical lens with positive optical power. The combined focal length of the first cemented doublet lens is between -25 and -15.

[0006] Preferably, the refractive index of the first lens is between 1.50 and 1.55, and the Abbe number is between 53 and 57; the refractive index of the second lens is between 1.85 and 1.90, and the Abbe number is between 37 and 42; the refractive index of the third lens is between 1.60 and 1.65, and the Abbe number is between 33 and 39; the refractive index of the fourth lens is between 1.86 and 1.92, and the Abbe number is between 37 and 42; and the refractive index of the fifth lens is between 1.77 and 1.95. The refractive index of the sixth lens is between 1.52 and 1.58, and the Abbe number is between 72 and 78. The refractive index of the seventh lens is between 1.56 and 1.62, and the Abbe number is between 57 and 63. The refractive index of the eighth lens is between 1.73 and 1.79, and the Abbe number is between 23 and 29. The refractive index of the ninth lens is between 1.52 and 1.58, and the Abbe number is between 25 and 31.

[0007] Preferably, the lens is divided into a front group and a rear group with the aperture stop as the boundary, wherein the first lens, the second lens, the third lens and the fourth lens constitute the front group, and the fifth lens, the sixth lens, the seventh lens, the eighth lens and the ninth lens constitute the rear group, and the ratio of the combined focal length of the front group to the combined focal length of the rear group satisfies the condition between 0.1 and 0.4.

[0008] In summary, this application has the following beneficial technical effects: light rays pass sequentially from the object side to the image side along the optical axis through the first lens, the second lens, the third lens, the fourth lens, the aperture stop, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, the filter, and the chip protective glass. The seventh lens and the eighth lens form a first cemented doublet lens. All the lenses are spherical glass lenses, and the filter is a visible light bandpass filter. This utility model achieves high resolution (8MP), large aperture (FNO = 2.0), wide field of view (diagonal field of view DFOV ≥ 72°), compact structure (TTL ≤ 30.0mm), large target surface (image height Φ ≈ 9.6mm), and low cost by using 9 spherical glass lenses to form 8 groups of 9-element optical structures. Attached Figure Description

[0009] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 This is an optical path diagram of the optical lens in Embodiment 1 of this utility model;

[0011] Figure 2 This is a dot plot of the visible light 435nm-656nm band in Embodiment 1 of this utility model;

[0012] Figure 3 This is the MTF curve of Embodiment 1 of this utility model in the visible light 435nm-656nm band;

[0013] Figure 4 This is a field curvature and distortion diagram of the visible light 435nm-656nm band in Embodiment 1 of this utility model;

[0014] Figure 5 This is a relative illuminance curve of the visible light 435nm-656nm band in Embodiment 1 of this utility model;

[0015] Figure 6 This is a defocused MTF curve of the visible light 435nm-656nm band in Embodiment 1 of this utility model;

[0016] Figure 7 This is a magnification chromatic difference curve diagram of the visible light 435nm-656nm band in Embodiment 1 of this utility model;

[0017] Figure 8 This is the optical path diagram of the optical lens in Embodiment 2 of this utility model;

[0018] Figure 9 This is a dot plot of the visible light 435nm-656nm band in Embodiment 2 of this utility model;

[0019] Figure 10 This is the MTF curve of Embodiment 2 of this utility model in the visible light 435nm-656nm band;

[0020] Figure 11 This is a field curvature and distortion diagram of the visible light 435nm-656nm band in Embodiment 2 of this utility model;

[0021] Figure 12 This is a relative illuminance curve in the visible light 435nm-656nm band of Embodiment 2 of this utility model;

[0022] Figure 13 This is a defocused MTF curve of the visible light 435nm-656nm band in Embodiment 2 of this utility model;

[0023] Figure 14 This is a magnification chromatic difference curve diagram in the visible light 435nm-656nm band of Embodiment 2 of this utility model.

[0024] The attached diagram lists the components represented by each number as follows:

[0025] 1. First lens; 2. Second lens; 3. Third lens; 4. Fourth lens; 21. Aperture; 5. Fifth lens; 6. Sixth lens; 7. Seventh lens; 8. Eighth lens; 9. Ninth lens; 22. Filter; 23. Chip protective glass. Detailed Implementation

[0026] The technical solutions of the present utility model 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 utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0027] The following is in conjunction with the appendix Figure 1-14 This application will be described in further detail.

[0028] Reference Figures 1-7 An embodiment of a wide-angle automotive front-view fixed-focus optical lens includes a lens, an aperture 21, a filter 22, and a chip protective glass 23. From the object side to the image side, along the optical axis, a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, an aperture 21, a fifth lens 5, a sixth lens 6, a seventh lens 7, an eighth lens 8, a ninth lens 9, a filter 22, and the chip protective glass 23 are arranged sequentially. The seventh lens 7 and the eighth lens 8 form a first cemented doublet lens. All lenses are spherical glass lenses, and the filter 22 is a visible light bandpass filter 22.

[0029] The first lens 1 is a meniscus glass spherical lens with negative optical power; the object-facing side of the first lens 1 is convex, and the image-facing side of the first lens 1 is concave.

[0030] The second lens 2 is a meniscus glass spherical lens with positive optical power; the object-facing side of the second lens 2 is convex, and the image-facing side of the second lens 2 is concave.

[0031] The third lens 3 is a double concave glass spherical lens with negative optical power; the object-facing side of the third lens 3 is concave, and the image-facing side of the third lens 3 is also concave.

[0032] The fourth lens 4 is a biconvex glass spherical lens with positive optical power; the object-facing side of the fourth lens 4 is convex, and the image-facing side of the fourth lens 4 is also convex.

[0033] The fifth lens 5 is a meniscus glass spherical lens with a positive optical power; the surface of the fifth lens 5 facing the object side is convex, and the surface of the fifth lens 5 facing the image side is concave.

[0034] The sixth lens 6 is a meniscus glass spherical lens with a positive optical power; the surface of the sixth lens 6 facing the object side is concave, and the surface of the sixth lens 6 facing the image side is convex.

[0035] The seventh lens 7 is a biconvex glass spherical lens with a positive optical power; the surface of the seventh lens 7 facing the object side is convex, and the surface of the seventh lens 7 facing the image side is also convex.

[0036] The eighth lens 8 is a biconcave glass spherical lens with a negative optical power; the surface of the eighth lens 8 facing the object side is concave, and the surface of the eighth lens 8 facing the image side is also concave;

[0037] The ninth lens 9 is a meniscus glass spherical lens with a positive optical power; the surface of the ninth lens 9 facing the object side is convex, and the surface of the ninth lens 9 facing the image side is concave.

[0038] The combined focal length of the first doublet lens is represented by f78, satisfying -25 < f78 < -15.

[0039] Refer to Figures 1-7 , the refractive index of the first lens 1 is represented by Nd1, the refractive index of the second lens 2 is represented by Nd2, the refractive index of the third lens 3 is represented by Nd3, and so on. The refractive index of the ninth lens 9 is represented by Nd9; the Abbe number of the first lens 1 is represented by Vd1, the refractive index of the second lens 2 is represented by the Abbe number Vd2, the Abbe number of the third lens 3 is represented by Vd3, and so on. The refractive index of the ninth lens 9 is represented by the Abbe number Vd9; the refractive index and Abbe number ranges of each lens are: the refractive index of the first lens 1 is 1.50 < Nd1 < 1.55, and the Abbe number is 53 < Vd1 < 57;

[0040] The refractive index of the second lens 2 is 1.85 < Nd2 < 1.90, and the Abbe number is 37 < Vd2 ≤ 42;

[0041] The refractive index of the third lens 3 is 1.60 < Nd3 < 1.65, and the Abbe number is 33 < Vd3 < 39;

[0042] The refractive index of the fourth lens 4 is 1.86 < Nd4 < 1.92, and the Abbe number is 37 < Vd4 < 42;

[0043] The refractive index of the fifth lens 5 is 1.77 < Nd5 < 1.83, and the Abbe number is 22 < Vd5 < 28;

[0044] The refractive index of the sixth lens 6 satisfies 1.52 < Nd6 < 1.58, and the Abbe number satisfies 72 < Vd6 < 78;

[0045] The refractive index of the seventh lens 7 satisfies 1.56 < Nd7 < 1.62, and the Abbe number satisfies 57 < Vd7 < 63;

[0046] The refractive index of the eighth lens 8 satisfies 1.73 < Nd8 < 1.79, and the Abbe number satisfies 23 < Vd8 < 29;

[0047] The refractive index of the ninth lens 9 satisfies 1.52 < Nd9 < 1.58, and the Abbe number satisfies 25 < Vd9 < 31.

[0048] Specifically, the refractive index of the first lens 1 is Nd1 = 1.5336, and the Abbe number is Vd1 = 55.47.

[0049] The refractive index of the second lens 2 is Nd2 = 1.883, and the Abbe number is Vd2 = 39.222.

[0050] The refractive index of the third lens 3 is Nd3 = 1.6201, and the Abbe number is Vd3 = 36.346.

[0051] The refractive index of the fourth lens 4 is Nd4 = 1.883, and the Abbe number is Vd4 = 39.222.

[0052] The refractive index of the fifth lens 5 is Nd5 = 1.8052, and the Abbe number is Vd5 = 25.456.

[0053] The refractive index of the sixth lens 6 is Nd6 = 1.5503, and the Abbe number is Vd6 = 75.509.

[0054] The refractive index of the seventh lens 7 is Nd7 = 1.5941, and the Abbe number is Vd7 = 60.475.

[0055] The refractive index of the eighth lens 8 is Nd8 = 1.7618, and the Abbe number is Vd8 = 26.608.

[0056] The refractive index of the ninth lens 9 is Nd9 = 1.9229, and the Abbe number is Vd9 = 20.88.

[0057] The first doublet lens is composed of the seventh lens 7 and the eighth lens 8, and its combined focal length is denoted as f78, and f78 = -18.895, satisfying -25 < f78 < -15.

[0058] Refer to Figures 1-7The optical lens is divided into two groups, front and rear, by the aperture stop 21. The first lens 1, the second lens 2, the third lens 3, and the fourth lens 4 form the front group, with a combined focal length denoted as ff. The fifth lens 5, the sixth lens 6, the seventh lens 7, the eighth lens 8, and the ninth lens 9 form the rear group, with a combined focal length denoted as fb. The ratio of the two groups, fb / ff, is 0.265, satisfying 0.1. <fb / ff<0.4。

[0059] Reference Figure 2 This is a dot plot of visible light in the 435nm-656nm band, where the wavelengths are 435nm, 486nm, 550nm, 586nm, and 656nm, with a weighting ratio of 9:27:30:29:10. Figure 2 It can be seen that the blur spots are relatively concentrated and evenly distributed across all fields of view. Furthermore, there is no phenomenon where the blur spots in a particular field of view are significantly separated vertically with varying wavelengths.

[0060] Reference Figure 3 This is the MTF curve of the present invention in the visible light 435nm-656nm band. The MTF curve represents the overall resolution of an optical lens, which is determined by... Figure 3 It can be seen that the MTF value of the entire field of view at 250 lp / mm is ≥0.25, and the image is clear.

[0061] Reference Figure 4 This diagram shows the field curvature and distortion in the visible light 435nm-656nm band of this invention. The distortion curve represents the magnitude of optical distortion at different field angles, expressed as a percentage (%). Figure 4 It can be seen that the absolute value of optical distortion is ≤19%.

[0062] Reference Figure 5 This is a relative illuminance curve for the visible light 435nm-656nm band of this invention. Figure 5 As can be seen, the curve descends smoothly, the relative illumination value at the maximum field of view is >0.7, and the image is relatively bright.

[0063] Reference Figure 6 The figure shows the defocus MTF curve of this invention in the visible light 435nm-656nm band, with a spatial frequency of 125lp / mm and a defocus range of -0.03mm to 0.03mm. Figure 6 This reflects the degree of field curvature correction. When a lens has field curvature, the center and periphery cannot be simultaneously sharp; that is, when the center of the field is adjusted to be at its sharpest, the edges are not sharp enough. It is necessary to adjust the sharpness of the center of the field to make the edges of the field sharper. Figure 6 It is evident that the field curvature correction was performed well.

[0064] Reference Figure 7 This is a magnification chromatic aberration curve in the visible light 435nm-656nm band of this invention. By combining this curve with the pixel size, the degree of magnification chromatic aberration correction can be determined. Figure 7 It can be seen that the magnification color difference correction is quite good.

[0065] The implementation principle of this embodiment is as follows: light rays travel from the object side to the image side along the optical axis, passing sequentially through the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the aperture 21, the fifth lens 5, the sixth lens 6, the seventh lens 7, the eighth lens 8, the ninth lens 9, the filter 22, and the chip protective glass 23. The seventh lens 7 and the eighth lens 8 form a first cemented doublet lens. All lenses are spherical glass lenses, and the filter 22 is a visible light bandpass filter. This invention achieves high resolution (8MP), a large aperture (FNO = 2.0), a wide field of view (diagonal field of view DFOV ≥ 72°), a compact structure (TTL ≤ 30.0mm), a large target surface (image height Φ ≈ 9.6mm), and low cost by using nine spherical glass lenses to form eight groups of nine-element optical structures.

[0066] Reference Figures 8-14 The difference between Example 2 and Example 1 is that the refractive index of the first lens 1 is Nd1 = 1.5336 and the Abbe number is Vd1 = 55.47.

[0067] The refractive index of the second lens 2 is Nd2 = 1.9004, and the Abbe number is Vd2 = 37.372;

[0068] The refractive index of the third lens 3 is Nd3 = 1.6201, and the Abbe number is Vd3 = 36.346;

[0069] The fourth lens 4 has a refractive index of Nd4 = 1.883 and an Abbe number of Vd4 = 39.222.

[0070] The refractive index of the fifth lens 5 is Nd5 = 1.8052, and the Abbe number is Vd5 = 25.448;

[0071] The refractive index of the sixth lens 6 is Nd6 = 1.5503, and the Abbe number is Vd6 = 75.509;

[0072] The refractive index of the seventh lens 7 is Nd7 = 1.5941, and the Abbe number is Vd7 = 60.475;

[0073] The refractive index of the eighth lens 8 is Nd8 = 1.7618, and the Abbe number is Vd8 = 26.608;

[0074] The refractive index Nd9 of the ninth lens 9 is 1.9229, and the Abbe number Vd9 is 20.88.

[0075] Referring to Figures 8-14 , the seventh lens 7 and the eighth lens 8 form a first doublet lens, and f78 = -19.717, satisfying -25 < f78 < -15; the combined focal length of the rear group is denoted as fb, and the ratio fb / ff = 0.214, satisfying 0.1 < fb / ff < 0.4.

[0076] Referring to Figure 9 , it is the spot diagram of the present utility model in the visible light band of 435nm - 656nm. Among them, five wavelengths of 435nm, 486nm, 550nm, 586nm, and 656nm are taken, and the weight ratio is 9:27:30:29:10. From Figure 9 it can be seen that the blur spots in each field of view are relatively concentrated and the distribution is relatively uniform. At the same time, there is no phenomenon that the blur spots in a certain field of view are separated up and down greatly with the wavelength.

[0077] Referring to Figure 10 , it is the MTF curve diagram of the present utility model in the visible light band of 435nm - 656nm. The MTF curve diagram represents the comprehensive resolution level of an optical lens. From Figure 10 it can be seen that the MTF value of the full field of view at 250 lp / mm ≥ 0.25, and the imaging is clear.

[0078] Referring to Figure 11 , it is the field curvature and distortion diagram of the present utility model in the visible light band of 435nm - 656nm. The distortion curve diagram represents the optical distortion magnitude values under different field of view angles, and the unit is %. From Figure 11 it can be seen that the absolute value of the optical distortion is ≤ 19%.

[0079] Referring to Figure 12 , it is the relative illumination curve diagram of the present utility model in the visible light band of 435nm - 656nm. From Figure 12 it can be seen that the curve drops smoothly, and the relative illumination value under the maximum field of view > 0.7, and the imaging picture is relatively bright.

[0080] Referring to Figure 13 , it is the defocus MTF curve diagram of the present utility model in the visible light band of 435nm - 656nm. The spatial frequency taken is 125 lp / mm, and the defocus range is from -0.03mm to 0.03mm. Figure 13 It can reflect the degree of field curvature correction. When a lens has field curvature, the result is that the center and the periphery cannot be in focus synchronously, that is, when the center of the field of view is adjusted to the clearest, the edge is not clear enough; it is necessary to reduce the clarity of the center of the field of view by callback to make the edge of the field of view clearer. From Figure 13It is evident that the field curvature correction was performed well.

[0081] Reference Figure 14 This is a magnification chromatic aberration curve in the visible light 435nm-656nm band of this invention. By combining this curve with the pixel size, the degree of magnification chromatic aberration correction can be determined. Figure 14 It can be seen that the magnification color difference correction is quite good.

[0082] The implementation principle of this embodiment is as follows: light rays travel from the object side to the image side along the optical axis, passing sequentially through the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the aperture 21, the fifth lens 5, the sixth lens 6, the seventh lens 7, the eighth lens 8, the ninth lens 9, the filter 22, and the chip protective glass 23. The seventh lens 7 and the eighth lens 8 form the first cemented doublet lens. All lenses are spherical glass lenses, and the filter 22 is a visible light bandpass filter. This invention achieves high resolution (8MP), a large aperture (FNO = 2.0), a wide field of view (diagonal field of view DFOV ≥ 72°), a compact structure (TTL ≤ 30.0mm), a large target surface (image height Φ ≈ 9.6mm), and low cost by using nine spherical glass lenses to form eight groups of nine-element optical structures.

[0083] In the description of this utility model, it should be understood that the terms "coaxial", "bottom", "one end", "top", "middle", "other end", "upper", "side", "top", "inner", "front", "center", "both ends", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0084] In this utility model, unless otherwise explicitly specified and limited, the terms "installation", "setting", "connection", "fixing", "screw connection", etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components or the interaction between two components. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0085] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A wide-angle automotive forward-looking fixed-focus optical lens, characterized in that, The system includes a lens, an aperture (21), a filter (22), and a chip protective glass (23). From the object side to the image side, along the optical axis, the following lenses are arranged sequentially: a first lens (1), a second lens (2), a third lens (3), a fourth lens (4), an aperture (21), a fifth lens (5), a sixth lens (6), a seventh lens (7), an eighth lens (8), a ninth lens (9), a filter (22), and the chip protective glass (23). The seventh lens (7) and the eighth lens (8) form a first cemented doublet lens. All lenses are spherical glass lenses. The filter (22) is a visible light bandpass filter (22). The first lens (1) is a meniscus spherical glass lens with negative optical power. The second lens... The first lens (2) is a meniscus glass spherical lens with positive optical power; the third lens (3) is a biconcave glass spherical lens with negative optical power; the fourth lens (4) is a biconvex glass spherical lens with positive optical power; the fifth lens (5) is a meniscus glass spherical lens with positive optical power; the sixth lens (6) is a meniscus glass spherical lens with positive optical power; the seventh lens (7) is a biconvex glass spherical lens with positive optical power; the eighth lens (8) is a biconcave glass spherical lens with negative optical power; and the ninth lens (9) is a meniscus glass spherical lens with positive optical power. The combined focal length of the first cemented doublet lens is between -25 and -15.

2. The wide-angle vehicle-mounted forward-looking fixed-focus optical lens according to claim 1, characterized in that: The first lens (1) has a refractive index between 1.50 and 1.55, and an Abbe number between 53 and 57; the second lens (2) has a refractive index between 1.85 and 1.90, and an Abbe number between 37 and 42; the third lens (3) has a refractive index between 1.60 and 1.65, and an Abbe number between 33 and 39; the fourth lens (4) has a refractive index between 1.86 and 1.92, and an Abbe number between 37 and 42; the fifth lens (5) has a refractive index between 1.77 and 1.

95. The refractive index of the sixth lens (6) is between 1.83 and 22, and the Abbe number is between 22 and 28; the refractive index of the seventh lens (7) is between 1.52 and 1.58, and the Abbe number is between 72 and 78; the refractive index of the seventh lens (7) is between 1.56 and 1.62, and the Abbe number is between 57 and 63; the refractive index of the eighth lens (8) is between 1.73 and 1.79, and the Abbe number is between 23 and 29; the refractive index of the ninth lens (9) is between 1.52 and 1.58, and the Abbe number is between 25 and 31.

3. A wide-angle vehicle-mounted forward-looking fixed-focus optical lens according to claim 2, characterized in that: The lens is divided into a front group and a rear group by the aperture stop (21). The first lens (1), the second lens (2), the third lens (3) and the fourth lens (4) form the front group, and the fifth lens (5), the sixth lens (6), the seventh lens (7), the eighth lens (8) and the ninth lens (9) form the rear group. The ratio of the combined focal length of the front group to the combined focal length of the rear group is between 0.1 and 0.4.

Images