CN117991479A - Laser radar receiving optical lens - Google Patents

Laser radar receiving optical lens Download PDF

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CN117991479A
CN117991479A CN202410399126.4A CN202410399126A CN117991479A CN 117991479 A CN117991479 A CN 117991479A CN 202410399126 A CN202410399126 A CN 202410399126A CN 117991479 A CN117991479 A CN 117991479A
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lens
object side
image side
optical
power
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CN202410399126.4A
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CN117991479B (en
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张丽芝
陆秋萍
段帆琳
喻军
毛昊阳
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NINGBO YONGXIN OPTICS CO Ltd
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NINGBO YONGXIN OPTICS CO Ltd
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Abstract

The invention discloses a laser radar receiving optical lens, which is formed by sequentially arranging a first lens with positive focal power, a first lens group with positive focal power and a second lens with negative focal power from an object side to an image side, wherein the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface; at least one of the object side surface and the image side surface of the second lens is a concave surface; the whole optical lens meets the following conditions ：0.8＜|f1/f|＜1.8,0.7＜|fm/f2|＜1.8,0.5＜|f2/f|＜2.6,1.2＜|TTL/f|＜1.8,0.1＜|TTL/imgH/FOV|＜0.2,1.20＜F#＜1.35,15＜VD1＜55,35＜VD2＜70;, and has the advantages that the lens has large light inlet quantity and high diffraction limit through the setting of small F number, and the optical power is reasonably distributed through the selection of the lens surface type and the materials, so that the effect of high resolution is realized.

Description

Laser radar receiving optical lens
Technical Field
The present disclosure relates to optical lenses, and particularly to a laser radar receiving optical lens.
Background
With the rapid development and progress of the existing driving assistance technology and imaging chip technology, the imaging quality of the vehicle-mounted laser radar is improved, and the corresponding optical lens is also required to be higher.
1) The smaller the F number is, the larger the laser radar light quantity is, the more laser is collected, the stronger the capability of detecting weak signals at a longer distance is, and the range of the laser radar is facilitated to be improved.
2) In some high performance vehicle lidar systems, multiple lenses of different functions are provided. The high-resolution lens can image details for intelligent recognition by a driver or software. However, many lenses are focused on large angles of view to avoid dead zones, and the resolution requirements are limited to imaging the general contours of the object.
The patent application CN202310524310.2 proposes a four-chip laser radar optical system, which uses a smaller number of spherical lenses to control the cost, but is limited by the optical system, and the F-number is larger, resulting in a lower diffraction limit and lower resolution.
The invention patent with the patent application number of CN202111144813.4 provides a five-piece laser radar lens, which realizes a larger field angle and a smaller F number, but the transfer function value under the condition of 60lp/mm of a higher line pair is only more than 0.4, and the use requirement of higher resolution is not met.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a laser radar receiving optical lens with high resolution under the condition of small F number.
The technical scheme adopted for solving the technical problems is as follows: a laser radar receiving optical lens is composed of a first lens, a first lens group and a second lens which are arranged from the object side to the image side in sequence,
The focal power of the first lens group is positive;
the first lens has positive focal power, the object side surface is a convex surface, and the image side surface is a concave surface;
the second lens has negative focal power, and at least one of the object side surface and the image side surface is a concave surface;
the whole optical lens meets the following conditions:
0.8＜|f1/f|＜1.8,0.7＜|fm/f2|＜1.8,0.5＜|f2/f|＜2.6,1.2＜|TTL/f|＜1.8,0.1＜|TTL/imgH/FOV|＜0.2,1.20＜F#＜1.35,15＜VD1＜55,35＜VD2＜70;
Wherein F is the focal length of the whole optical lens, TTL is the total optical length of the whole optical lens, F 1、fm、f2 is the focal lengths of the first lens, the first lens group and the second lens respectively, FOV is the maximum field angle of the whole optical lens, imgH is half of the image height corresponding to the maximum field angle, F# is the F number of the whole optical lens, VD 1 is the dispersion coefficient of the first lens, and VD 2 is the dispersion coefficient of the second lens.
Compared with the prior art, the invention has the advantages that the lens has large light incoming quantity and high diffraction limit by setting the small F number, which is beneficial to realizing high resolution imaging effect; meanwhile, through the selection of the lens surface type and the materials, the combination of the spherical lens and the aspherical lens is adopted, the focal power is reasonably distributed, the effect of high resolution is realized on the basis of small F number, and the use requirement is met.
In a preferred embodiment, the first lens group is composed of a third lens with negative focal power and a fourth lens with positive focal power, which are sequentially arranged from an object side to an image side, wherein an object side surface of the third lens is a convex surface, an image side surface of the third lens is a concave surface, at least one of the object side surface and the image side surface of the fourth lens is a convex surface, a focal length of the third lens is f 3, and a focal length of the fourth lens is f 4, so that the conditions are satisfied: 0.8 < |f 3/f|＜1.4,1.0＜|f3/f4 | < 2.6.
Preferably, the second lens is an aspherical lens, and at least one lens in the first lens group is an aspherical lens.
In another preferred embodiment, the first lens group is formed by sequentially arranging, from an object side to an image side, a third lens with negative focal power, a fourth lens with positive focal power and a fifth lens with negative focal power, wherein an object side surface of the third lens is a concave surface, an image side surface is a concave surface, an object side surface of the fourth lens is a convex surface, an image side surface is a convex surface, an object side surface of the fifth lens is a concave surface, an image side surface is a concave surface, a focal length of the third lens is f 3, a focal length of the fourth lens is f 4, a focal length of the fifth lens is f 5, and the following conditions are satisfied: 0.8 < |f 3/f|＜1.4,1.0＜|f3/f4|＜2.6,3.5＜|f5/f| < 3.7.
Preferably, the second lens is an aspherical lens, and at least two lenses in the first lens group are aspherical lenses.
Another preferred embodiment of the present invention is that the first lens group is composed of, in order from the object side to the image side, a third lens with negative focal power, a fourth lens with positive focal power, a fifth lens with negative focal power, and a sixth lens with positive focal power, wherein the object side of the third lens is concave, the image side is concave, the object side of the fourth lens is convex, the image side is convex, the object side of the fifth lens is convex, the image side is concave, at least one of the object side and the image side of the sixth lens is convex, the focal length of the third lens is f 3, the focal length of the fourth lens is f 4, the focal length of the fifth lens is f 5, the focal length of the sixth lens is f 6, and the conditions are satisfied ：0.8＜|f3/f|＜1.7,1.0＜|f3/f4|＜2.6,0.8＜|f5/f|＜1.4,0.8＜|f5/f6|＜1.5.
Preferably, the second lens is an aspherical lens, and at least two lenses in the first lens group are aspherical lenses.
Drawings
FIG. 1 is a schematic diagram of an optical system according to embodiment 1 of the present invention;
FIG. 2 is a graph showing the transfer function of example 1 of the present invention;
FIG. 3 is a schematic view of an optical system according to embodiment 2 of the present invention;
FIG. 4 is a graph showing the transfer function of example 2 of the present invention;
FIG. 5 is a schematic view of an optical system according to embodiment 3 of the present invention;
FIG. 6 is a graph showing the transfer function of example 3 of the present invention;
FIG. 7 is a schematic view of an optical system according to embodiment 4 of the present invention;
FIG. 8 is a graph showing the transfer function of example 4 of the present invention;
FIG. 9 is a schematic view of an optical system according to embodiment 5 of the present invention;
FIG. 10 is a graph showing the transfer function of example 5 of the present invention;
FIG. 11 is a schematic view of an optical system according to embodiment 6 of the present invention;
FIG. 12 is a graph showing the transfer function of example 6 of the present invention;
FIG. 13 is a schematic view of an optical system according to embodiment 7 of the present invention;
FIG. 14 is a graph showing the transfer function of example 7 of the present invention.
Detailed Description
Embodiments of the present invention will now be described in detail with reference to the drawings, which are intended to be used as references and illustrations only, and are not intended to limit the scope of the invention.
In the drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for convenience of explanation. The drawings are merely examples and are not necessarily drawn to scale.
In an embodiment, the lens surface relief is dependent on the radius of curvature of the lens surface. When the curvature radius of the object side surface of the lens is larger than 0, the surface is a convex surface; when equal to 0, the plane is the plane; less than 0, the concave surface. When the curvature radius of the image side surface of the lens is larger than 0, the surface is a concave surface; when equal to 0, the plane is the plane; and less than 0, is convex.
The first, second and third embodiments of the present application provide a lidar receiving optical lens including four lenses, in order from an object side to an image side: the lens system comprises a first lens L1 with positive focal power, a first lens group m with positive focal power, a second lens L2 with negative focal power, and a third lens L3 and a fourth lens L4 which are sequentially arranged from the object side to the image side.
In an exemplary embodiment, the object-side surface of the first lens L1 is convex, which is beneficial to collect light and improve relative illumination. The focal power of the first lens L1 is positive, which is favorable for collecting light beams and controlling the trend of light entering the lens, so that the caliber of the rear lens is controlled. The focal length f 1 of the first lens L1 and the focal length f of the lens satisfy: the ratio is less than 1.8 and is less than |f 1/f| < 0.8, and reasonable setting of the ratio is beneficial to reasonable distribution of optical power, control of light trend and high resolution of the lens. The dispersion coefficient VD 1 of the first lens L1 satisfies: 15 < VD 1 < 55.
In an exemplary embodiment, the focal length f m of the first lens group m and the focal length f 2 of the second lens L2 satisfy: and 0.7 < |f m/f2 | < 1.8, and reasonably setting the proportional relation is favorable for reasonably distributing the focal power, controlling the light trend, enabling the light to smoothly reach the second lens L2, reducing aberration and improving resolution. The first lens group m is provided with at least one aspheric lens, so that the trend of light rays with different fields of view can be controlled, and aberration can be reduced.
In an exemplary embodiment, the second lens L2 has negative optical power, and at least one of the object side surface and the image side surface is concave; the focal length f 2 of the second lens L2 and the focal length f of the lens satisfy: the ratio is less than 2.6 in the ratio of 0.5 < |f 2/f|, the reasonable arrangement of the ratio is beneficial to reasonably distributing the focal power, controlling the light trend, enabling the light to smoothly reach the image surface, reducing the sensitivity of the lens and improving the resolution of the lens. The second lens L2 is an aspheric lens, and can control the trend of light rays with different fields of view and reduce aberration. The dispersion coefficient VD 2 of the second lens L2 satisfies: 35 < VD 2 < 70.
In an exemplary embodiment, the optical total length TTL of the lens and the lens focal length f satisfy: 1.2 < |TTL/f| < 1.8, and the proportional relation is reasonably set, so that the total length of the lens can be controlled, and the length of the lens can be reduced while the use requirement is met.
In an exemplary embodiment, the optical total length TTL of the lens, half of the maximum field angle of the lens corresponding to the image height imgH, and the maximum field angle FOV of the lens satisfy: the ratio is less than 0.1 < |TTL/imgH/FOV| < 0.2, the reasonable setting of the ratio is beneficial to controlling the total length of the lens and reasonably adjusting the image height.
In an exemplary embodiment, the F number f# of the lens satisfies: f# -1.20 is less than F# -1.35, F number is reasonably set, the light entering quantity of the lens is controlled, and the detection capability of the laser radar is enhanced.
In an exemplary embodiment, the third lens L3 has negative optical power, causing the light rays to diverge for subsequent aspheric lens shaping. The object side surface is a convex surface corresponding to the image side surface of the first lens L1, which is beneficial to smooth light passing and reduces lens sensitivity. The focal length f 3 of the third lens L3 and the lens focal length f satisfy: 0.8 < |f 3/f| < 1.4, and the reasonable setting of the proportional relation is beneficial to reasonably distributing the optical power.
In the exemplary embodiment, the fourth lens L4 has positive optical power, corresponding to the third lens L3 having negative optical power, causing the light rays to converge to image on the image side. The focal length f 3 of the third lens L3 and the focal length f 4 of the fourth lens L4 satisfy: 1.0 < |f 3/f4 | < 2.6, and reasonably setting the proportional relationship is beneficial to reasonably distributing the focal power.
In the exemplary embodiment, the stop STO is located at the object side of the third lens L3 in the first lens group m, and the distance between the stop STO and the image side of the first lens L1 is smaller, so that the light passes through the stop STO smoothly, the sensitivity of the lens is reduced, the aberration is reduced, and the lens length and the lens number are controlled.
In an exemplary embodiment, to improve the imaging quality of a lens and reduce the aberration in an imaging system, an aspherical lens is used, the surface shape of which satisfies the following equation:
Wherein y represents a radial coordinate value of the lens perpendicular to the optical axis, and Z is a sagittal height from the aspherical vertex when the aspherical lens is positioned at a height y along the optical axis direction. c=1/R, R denotes the corresponding aspherical lens face-type central radius of curvature, k denotes the conic coefficient, and the parameter A, B, C, D, E, F, G, H is the 2 nd, 4 th, 6 th, 8 th, 10 th, 12 th, 14 th, 16 th order polynomial of the higher order aspherical polynomial.
In an exemplary embodiment, the materials of the spherical lens and the aspherical lens may be glass. Compared with the plastic aspheric surface, the glass aspheric surface not only can realize the aberration reduction function of the aspheric surface, but also has the thermal stability of the glass, and has a better use effect.
In light of the foregoing description, more particular embodiments and figures are set forth below:
Embodiment one:
As shown in fig. 1, there are arranged in order from the object side to the image side: the optical power of the lens system comprises a first lens L1 with positive optical power, a diaphragm STO, a third lens L3 with negative optical power, a fourth lens L4 with positive optical power, a second lens L2 with negative optical power, an optical filter G1, a protective glass G2 and an image plane IMA, wherein the third lens L3 and the fourth lens L4 form a first lens group m with positive optical power, the object side surface of the first lens L1 is a convex surface, the image side surface is a concave surface, the object side surface of the third lens L3 is a convex surface, the image side surface is a concave surface, the object side surface of the fourth lens L4 is a concave surface, the object side surface of the second lens L2 is a concave surface, and the image side surface is a concave surface; the third lens L3, the fourth lens L4, and the second lens L2 are aspherical lenses.
The physical optical parameters of this example are shown in table 1:
TABLE 1
The aspherical surface profile parameters of this example are shown in table 2:
TABLE 2
The transfer function graph of this embodiment is shown in fig. 2, and fig. 2 shows that in the range of 100lp/mm, the transfer function value of the central field of view (the curve coincidence of the meridian of 0.0000mm and the sagittal of 0.0000) is greater than 0.6, the transfer function value of the edge field of view (the meridian of 5.6862mm and the sagittal of 5.6862, the curve non-coincidence) is about 0.5, and the resolution is higher.
Embodiment two:
As shown in fig. 3, there are arranged in order from the object side to the image side: the optical power of the lens system comprises a first lens L1 with positive optical power, a diaphragm STO, a third lens L3 with negative optical power, a fourth lens L4 with positive optical power, a second lens L2 with negative optical power, an optical filter G1, a protective glass G2 and an image plane IMA, wherein the third lens L3 and the fourth lens L4 form a first lens group m with positive optical power, the object side surface of the first lens L1 is a convex surface, the image side surface is a concave surface, the object side surface of the third lens L3 is a convex surface, the image side surface is a concave surface, the object side surface of the fourth lens L4 is a convex surface, the object side surface of the second lens L2 is a convex surface, and the image side surface is a concave surface; the third lens L3, the fourth lens L4, and the second lens L2 are aspherical lenses.
The physical optical parameters of this example are shown in table 3:
TABLE 3 Table 3
The aspherical surface profile parameters of this example are shown in table 4:
TABLE 4 Table 4
The transfer function graph of this embodiment is shown in fig. 4, and fig. 4 shows that in the range of 100lp/mm, the transfer function value of the central field of view (the curve coincidence of the meridian of 0.0000mm and the sagittal of 0.0000) is greater than 0.6, the transfer function value of the edge field of view (the meridian of 5.6570mm and the sagittal of 5.6570, the curve non-coincidence) is greater than 0.2, and the resolution is higher.
Embodiment III:
As shown in fig. 5, in order from the object side to the image side, there are arranged: the optical power of the lens system comprises a first lens L1 with positive optical power, a diaphragm STO, a third lens L3 with negative optical power, a fourth lens L4 with positive optical power, a second lens L2 with negative optical power, an optical filter G1, a protective glass G2 and an image plane IMA, wherein the third lens L3 and the fourth lens L4 form a first lens group m with positive optical power, the object side surface of the first lens L1 is a convex surface, the image side surface is a concave surface, the object side surface of the third lens L3 is a convex surface, the image side surface is a concave surface, the object side surface of the fourth lens L4 is a concave surface, the object side surface of the second lens L2 is a convex surface, and the image side surface is a concave surface; the third lens L3 and the second lens L2 are aspherical lenses.
The physical optical parameters of this example are shown in table 5:
TABLE 5
The aspherical surface profile parameters of this example are shown in table 6:
TABLE 6
The transfer function graph of this embodiment is shown in fig. 6, and fig. 6 shows that in the range of 100lp/mm, the transfer function value of the central field of view (the curve coincidence of the meridian of 0.0000mm and the sagittal of 0.0000) is greater than 0.6, the transfer function value of the edge field of view (the meridian of 5.6563mm and the sagittal of 5.6563, the curve non-coincidence) is greater than 0.2, and higher resolution is achieved.
The fourth and fifth embodiments of the present application provide a lidar receiving optical lens including five lenses, arranged in order from an object side to an image side: the lens system comprises a first lens L1 with positive focal power, a first lens group m with positive focal power, a second lens L2 with negative focal power, and a third lens L3, a fourth lens L4 and a fifth lens L5 which are sequentially arranged from the object side to the image side.
In an exemplary embodiment, the object-side surface of the first lens L1 is convex, which is beneficial to collect light and improve relative illumination. The focal power of the first lens L1 is positive, which is favorable for collecting light beams and controlling the trend of light entering the lens, so that the caliber of the rear lens is controlled. The focal length f 1 of the first lens L1 and the focal length f of the lens satisfy: the ratio is less than 1.8 and is less than |f 1/f| < 0.8, and reasonable setting of the ratio is beneficial to reasonable distribution of optical power, control of light trend and high resolution of the lens. The dispersion coefficient VD 1 of the first lens L1 satisfies: 15 < VD 1 < 55.
In an exemplary embodiment, the focal length f m of the first lens group m and the focal length f 2 of the second lens L2 satisfy: and 0.7 < |f m/f2 | < 1.8, and reasonably setting the proportional relation is favorable for reasonably distributing the focal power, controlling the light trend, enabling the light to smoothly reach the second lens, reducing aberration and improving resolution. The first lens group m has two aspherical lenses, which can control the trend of the light rays of different fields.
In an exemplary embodiment, the second lens L2 has negative optical power, and at least one of the object side surface and the image side surface is concave; the focal length f 2 of the second lens L2 and the focal length f of the lens satisfy: the ratio is less than 2.6 in the ratio of 0.5 < |f 2/f|, the reasonable arrangement of the ratio is beneficial to reasonably distributing the focal power, controlling the light trend, enabling the light to smoothly reach the image surface, reducing the sensitivity of the lens and improving the resolution of the lens. The second lens L2 is an aspheric lens, and can control the trend of light rays with different fields of view and reduce aberration. The dispersion coefficient VD 2 of the second lens L2 satisfies: VD 2 is more than 35 and less than 70,
In an exemplary embodiment, the optical total length TTL of the lens and the lens focal length f satisfy: 1.2 < |TTL/f| < 1.8, and the proportional relation is reasonably set, so that the total length of the lens can be controlled, and the length of the lens can be reduced while the use requirement is met.
In an exemplary embodiment, the optical total length TTL of the lens, half of the maximum field angle of the lens corresponding to the image height imgH, and the maximum field angle FOV of the lens satisfy: the ratio is less than 0.1 < |TTL/imgH/FOV| < 0.2, the reasonable setting of the ratio is beneficial to controlling the total length of the lens and reasonably adjusting the image height.
In an exemplary embodiment, the F number f# of the lens satisfies: f# -1.20 is less than F# -1.35, F number is reasonably set, the light entering quantity of the lens is controlled, and the detection capability of the laser radar is enhanced.
In an exemplary embodiment, the third lens L3 has negative optical power, causing the light rays to diverge for subsequent aspheric lens shaping. The focal length f 3 of the third lens L3 and the lens focal length f satisfy: 0.8 < |f 3/f| < 1.4, and the reasonable setting of the proportional relation is beneficial to reasonably distributing the optical power. The third lens L3 is an aspheric lens, and can control the trend of light rays with different fields of view and reduce aberration.
In the exemplary embodiment, the fourth lens L4 has positive optical power, corresponding to the third lens L3 having negative optical power, causing the light rays to converge to image on the image side. The focal length f 3 of the third lens L3 and the focal length f 4 of the fourth lens L4 satisfy: 1.0 < |f 3/f4 | < 2.6, and reasonably setting the proportional relationship is beneficial to reasonably distributing the focal power.
In the exemplary embodiment, the fifth lens L5 has negative power, slightly diverges the converging light beam passing through the fourth lens L4, gently propagates the light, lightens the imaging burden of the second lens L2, and improves the imaging resolution. The fifth lens L5 is an aspheric lens, and can control the trend of light rays with different fields of view and reduce aberration. The focal length f 5 of the fifth lens L5 and the lens focal length f satisfy: 3.5 < |f 5/f| < 3.7, and the reasonable setting of the proportional relationship is beneficial to reasonably distributing the optical power.
In the exemplary embodiment, the stop STO is located between the third lens L3 and the fourth lens L4, the third lens L3 on the object side is a biconcave lens, and the fourth lens L4 on the image side is a biconvex lens, so that the light is controlled not to excessively diverge or converge, which is beneficial for controlling the lens length. And the combination of positive and negative focal powers of the third lens L3 and the fourth lens L4 can lead light rays to smoothly pass through the diaphragm STO, reduce the sensitivity of the lens, reduce aberration and control the length of the lens and the number of lenses.
In an exemplary embodiment, to improve the imaging quality of a lens and reduce the aberration in an imaging system, an aspherical lens is used, the surface shape of which satisfies the following equation:
Wherein y represents a radial coordinate value of the lens perpendicular to the optical axis, and Z is a sagittal height from the aspherical vertex when the aspherical lens is positioned at a height y along the optical axis direction. c=1/R, R denotes the corresponding aspherical lens face-type central radius of curvature, k denotes the conic coefficient, and the parameter A, B, C, D, E, F, G, H is the 2 nd, 4 th, 6 th, 8 th, 10 th, 12 th, 14 th, 16 th order polynomial of the higher order aspherical polynomial.
In an exemplary embodiment, the materials of the spherical lens and the aspherical lens may be glass. Compared with the plastic aspheric surface, the glass aspheric surface not only can realize the aberration reduction function of the aspheric surface, but also has the thermal stability of the glass, and has a better use effect.
In light of the foregoing description, more particular embodiments and figures are set forth below:
Embodiment four:
as shown in fig. 7, in order from the object side to the image side, there are arranged: the first lens group m with positive focal power is composed of a first lens L1 with positive focal power, a third lens L3 with negative focal power, a diaphragm STO, a fourth lens L4 with positive focal power, a fifth lens L5 with negative focal power, a second lens L2 with negative focal power, a filter G1, a protective glass G2 and an image plane IMA, the third lens L3, the fourth lens L4 and the fifth lens L5, the object side of the first lens element L1 is convex, the image side of the first lens element L2 is concave, the object side of the third lens element L3 is concave, the image side of the third lens element L4 is concave, the object side of the fourth lens element L4 is convex, the image side of the fifth lens element L5 is concave, the object side of the second lens element L2 is concave, and the image side of the second lens element L2 is concave; the third lens L3, the fifth lens L5, and the second lens L2 are aspherical lenses.
The physical optical parameters of this example are shown in table 7:
TABLE 7
The aspherical surface profile parameters of this example are shown in table 8:
TABLE 8
The transfer function graph of this embodiment is shown in fig. 8, and fig. 8 shows that in the range of 100lp/mm, the transfer function value of the central field of view (the curve coincidence of the meridian of 0.0000mm and the sagittal of 0.0000) is greater than 0.6, the transfer function value of the edge field of view (the meridian of 5.7003mm and the sagittal of 5.7003, the curve non-coincidence) is greater than 0.2, and the resolution is higher.
Fifth embodiment:
As shown in fig. 9, in order from the object side to the image side, there are arranged: the first lens group m with positive focal power is composed of a first lens L1 with positive focal power, a third lens L3 with negative focal power, a diaphragm STO, a fourth lens L4 with positive focal power, a fifth lens L5 with negative focal power, a second lens L2 with negative focal power, a filter G1, a protective glass G2 and an image plane IMA, the third lens L3, the fourth lens L4 and the fifth lens L5, the object side of the first lens element L1 is convex, the image side of the first lens element L2 is concave, the object side of the third lens element L3 is concave, the image side of the third lens element L4 is concave, the object side of the fourth lens element L4 is convex, the image side of the fifth lens element L5 is concave, the object side of the second lens element L2 is concave, and the image side of the second lens element L2 is convex; the third lens L3, the fifth lens L5, and the second lens L2 are aspherical lenses.
The physical optical parameters of this example are shown in table 9:
TABLE 9
The aspherical surface profile parameters of this example are shown in table 10:
Table 10
The transfer function graph of this embodiment is shown in fig. 10, and fig. 10 shows that in the range of 100lp/mm, the transfer function value of the central field of view (the curve coincidence of the meridian of 0.0000mm and the sagittal of 0.0000) is greater than 0.6, and the transfer function value of the edge field of view (the meridian of 5.7055mm and the sagittal of 5.7055, the curve non-coincidence) is greater than 0.2, with higher resolution.
In the sixth and seventh embodiments of the present application, there is provided a lidar receiving optical lens including six lenses, arranged in order from an object side to an image side: the lens system comprises a first lens L1 with positive focal power, a first lens group m with positive focal power, a second lens L2 with negative focal power, and a third lens L3, a fourth lens L4, a fifth lens L5 and a sixth lens L6 which are sequentially arranged from the object side to the image side.
In an exemplary embodiment, the object-side surface of the first lens L1 is convex, which is beneficial to collect light and improve relative illumination. The focal power of the first lens L1 is positive, which is favorable for collecting light beams and controlling the trend of light entering the lens, so that the caliber of the rear lens is controlled. The focal length f 1 of the first lens L1 and the focal length f of the lens satisfy: the ratio is less than 1.8 and is less than |f 1/f| < 0.8, and reasonable setting of the ratio is beneficial to reasonable distribution of optical power, control of light trend and high resolution of the lens. The dispersion coefficient VD 1 of the first lens L1 satisfies: VD 1 is more than 15 and less than 55,
In an exemplary embodiment, the focal length f m of the first lens group m and the focal length f 2 of the second lens satisfy: and 0.7 < |f m/f2 | < 1.8, and reasonably setting the proportional relation is favorable for reasonably distributing the focal power, controlling the light trend, enabling the light to smoothly reach the second lens L2, reducing aberration and improving resolution. The first lens group m has two aspherical lenses, which can control the trend of light rays with different fields of view and reduce aberration.
In an exemplary embodiment, the second lens L2 has negative optical power, and at least one of the object side surface and the image side surface is concave; the focal length f 2 of the second lens L2 and the focal length f of the lens satisfy: the ratio is less than 2.6 in the ratio of 0.5 < |f 2/f|, the reasonable arrangement of the ratio is beneficial to reasonably distributing the focal power, controlling the light trend, enabling the light to smoothly reach the image surface, reducing the sensitivity of the lens and improving the resolution of the lens. The second lens L2 is an aspheric lens, and can control the trend of light rays with different fields of view and reduce aberration. The dispersion coefficient VD 2 of the second lens L2 satisfies: VD 2 is more than 35 and less than 70,
In an exemplary embodiment, the optical total length TTL of the lens and the lens focal length f satisfy: 1.2 < |TTL/f| < 1.8, and the proportional relation is reasonably set, so that the total length of the lens can be controlled, and the length of the lens can be reduced while the use requirement is met.
In an exemplary embodiment, the optical total length TTL of the lens, half of the maximum field angle of the lens corresponding to the image height imgH, and the maximum field angle FOV of the lens satisfy: the ratio is less than 0.1 < |TTL/imgH/FOV| < 0.2, the reasonable setting of the ratio is beneficial to controlling the total length of the lens and reasonably adjusting the image height.
In an exemplary embodiment, the F number f# of the lens satisfies: f# -1.20 is less than F# -1.35, F number is reasonably set, the light entering quantity of the lens is controlled, and the detection capability of the laser radar is enhanced.
In an exemplary embodiment, the third lens L3 has negative optical power, causing the light rays to diverge for subsequent aspheric lens shaping. The focal length f 3 of the third lens L3 and the lens focal length f satisfy: 0.8 < |f 3/f| < 1.7, and the reasonable setting of the proportional relation is beneficial to reasonably distributing the optical power. The third lens L3 is an aspheric lens, and can control the trend of light rays with different fields of view and reduce aberration.
In the exemplary embodiment, the fourth lens L4 has positive optical power, corresponding to the third lens L3 having negative optical power, causing the light rays to converge to image on the image side. The focal length f 3 of the third lens L3 and the focal length f 4 of the fourth lens L4 satisfy: 1.0 < |f 3/f4 | < 2.6, and reasonably setting the proportional relationship is beneficial to reasonably distributing the focal power.
In an exemplary embodiment, the fifth lens L5 has negative power, so that the converging light beam passing through the fourth lens L4 diverges again for the subsequent lens shaping, improving the imaging resolution. The fifth lens L5 is an aspheric lens, and can control the trend of light rays with different fields of view and reduce aberration. The focal length f5 of the fifth lens L5 and the lens focal length f satisfy: 0.8 < |f 5/f| < 1.4, and the reasonable setting of the proportional relation is beneficial to reasonably distributing the optical power.
In the exemplary embodiment, the sixth lens L6 has positive power, and receives one negative lens each in front and rear, so that light passes smoothly, and the imaging load of the second lens is reduced. The focal length f 6 of the sixth lens L6 and the focal length f 5 of the fifth lens L5 satisfy: 0.8 < |f 5/f6 | < 1.5, and reasonably setting the proportional relationship is beneficial to reasonably distributing the focal power.
In the exemplary embodiment, the stop STO is located between the third lens L3 and the fourth lens L4 in the first lens group m, the third lens L3 on the object side is a biconcave lens, and the fourth lens L4 on the image side is a biconvex lens, so that the light is controlled not to excessively diverge or converge, which is advantageous for controlling the lens length. And the combination of positive and negative focal powers of the third lens L3 and the fourth lens L4 can lead light rays to smoothly pass through the diaphragm STO, reduce the sensitivity of the lens, reduce aberration and control the length of the lens and the number of lenses.
In an exemplary embodiment, to improve the imaging quality of a lens and reduce the aberration in an imaging system, an aspherical lens is used, the surface shape of which satisfies the following equation:
Wherein y represents a radial coordinate value of the lens perpendicular to the optical axis, and Z is a sagittal height from the aspherical vertex when the aspherical lens is positioned at a height y along the optical axis direction. c=1/R, R denotes the corresponding aspherical lens face-type central radius of curvature, k denotes the conic coefficient, and the parameter A, B, C, D, E, F, G, H is the 2 nd, 4 th, 6 th, 8 th, 10 th, 12 th, 14 th, 16 th order polynomial of the higher order aspherical polynomial.
In an exemplary embodiment, the materials of the spherical lens and the aspherical lens may be glass. Compared with the plastic aspheric surface, the glass aspheric surface not only can realize the aberration reduction function of the aspheric surface, but also has the thermal stability of the glass, and has a better use effect.
From the above description of the embodiments, more particular embodiments and the accompanying drawings will be described in detail below:
Example six:
As shown in fig. 11, in order from the object side to the image side, there are arranged: the optical system comprises a first lens L1 with positive focal power, a third lens L3 with negative focal power, a diaphragm STO, a fourth lens L4 with positive focal power, a fifth lens L5 with negative focal power, a sixth lens L6 with positive focal power, a second lens L2 with negative focal power, an optical filter G1, a protective glass G2 and an image plane IMA, wherein the third lens L3, the fourth lens L4, the fifth lens L5 and the sixth lens L6 form a first lens group m with positive focal power, the first lens L1 object side is a convex surface, the image side is a concave surface, the third lens L3 object side is a concave surface, the image side is a concave surface, the fourth lens L4 object side is a convex surface, the fifth lens L5 object side is a convex surface, the image side is a concave surface, the sixth lens L6 object side is a convex surface, the image side is a convex surface, the second lens L2 object side is a concave surface, and the image side is a concave surface; the third lens L3, the fifth lens L5, and the second lens L2 are aspherical lenses.
The physical optical parameters of this example are shown in table 11:
TABLE 11
The aspherical surface profile parameters of this example are shown in table 12:
Table 12
As shown in fig. 12, fig. 12 shows that in the range of 100lp/mm, the transfer function value of the central field of view (the curve of 0.0000mm meridian and 0.0000 sagittal is coincident) is greater than 0.6, the transfer function value of the edge field of view (the curve of 5.6523mm meridian and 5.6523 sagittal is not coincident) is about 0.5, and the resolution is high.
Embodiment seven:
As shown in fig. 13, in order from the object side to the image side, there are arranged: the optical system comprises a first lens L1 with positive focal power, a third lens L3 with negative focal power, a diaphragm STO, a fourth lens L4 with positive focal power, a fifth lens L5 with negative focal power, a sixth lens L6 with positive focal power, a second lens L2 with negative focal power, an optical filter G1, a protective glass G2 and an image plane IMA, wherein the third lens L3, the fourth lens L4, the fifth lens L5 and the sixth lens L6 form a first lens group m with positive focal power, the first lens L1 object side is a convex surface, the image side is a concave surface, the third lens L3 object side is a concave surface, the image side is a concave surface, the fourth lens L4 object side is a convex surface, the fifth lens L5 object side is a convex surface, the image side is a concave surface, the sixth lens L6 object side is a convex surface, the image side is a concave surface, the second lens L2 object side is a convex surface, and the image side is a concave surface; the third lens L3, the fifth lens L5, and the second lens L2 are aspherical lenses.
The physical optical parameters of this example are shown in table 13:
TABLE 13
The aspherical surface profile parameters of this example are shown in table 14:
TABLE 14
The transfer function graph of this example is shown in fig. 14, and fig. 14 shows that in this example 7, in the range of 100lp/mm, the transfer function value of the central field of view (the curve of 0.0000mm meridian and 0.0000 sagittal overlap) is greater than 0.6, the transfer function value of the edge field of view (5.6510 mm meridian and 5.6510 sagittal, the curve does not overlap) is greater than 0.5, and higher resolution is achieved.
As can be seen from the above description, the high resolution of the optical system requires the mutual matching of the lenses, so the first, second and third embodiments adopt four lens elements with positive, negative, positive and negative focal powers from the object side to the image side, so that the lens elements achieve the imaging effect of high resolution and large image plane; the fourth and fifth embodiments are based on the first three embodiments, in which a negative lens is added in front of the last lens, the edge MTF is reduced, but the image plane size is increased; the sixth embodiment and the seventh embodiment are based on the first three embodiments, and a negative lens and a positive lens are added at the diaphragm, so that the imaging resolution is improved.
The physical parameters of each example are shown in table 15:
TABLE 15
The foregoing description of the embodiments of the present invention is merely illustrative, and the scope of the invention is not limited to the embodiments of the invention, but can be modified according to the scope of the appended claims.

Claims (7)

1. A laser radar receiving optical lens is composed of a first lens, a first lens group and a second lens which are arranged from the object side to the image side in sequence,
The focal power of the first lens group is positive;
the first lens has positive focal power, the object side surface is a convex surface, and the image side surface is a concave surface;
the second lens has negative focal power, and at least one of the object side surface and the image side surface is a concave surface;
the whole optical lens meets the following conditions:
0.8＜|f1/f|＜1.8,0.7＜|fm/f2|＜1.8,0.5＜|f2/f|＜2.6,1.2＜|TTL/f|＜1.8,0.1＜|TTL/imgH/FOV|＜0.2,1.20＜F#＜1.35,15＜VD1＜55,35＜VD2＜70;
Wherein F is the focal length of the whole optical lens, TTL is the total optical length of the whole optical lens, F 1、fm、f2 is the focal lengths of the first lens, the first lens group and the second lens respectively, FOV is the maximum field angle of the whole optical lens, imgH is half of the image height corresponding to the maximum field angle, F# is the F number of the whole optical lens, VD 1 is the dispersion coefficient of the first lens, and VD 2 is the dispersion coefficient of the second lens.
2. The lidar receiving optical lens of claim 1, wherein the first lens group comprises a third lens with negative focal power and a fourth lens with positive focal power, which are sequentially arranged from an object side to an image side, wherein an object side surface of the third lens is a convex surface, an image side surface is a concave surface, at least one of the object side surface and the image side surface of the fourth lens is a convex surface, a focal length of the third lens is f 3, and a focal length of the fourth lens is f 4, and the conditions are satisfied: 0.8 < |f 3/f|＜1.4,1.0＜|f3/f4 | < 2.6.
3. The lidar receiving optical lens of claim 1 wherein the second lens is an aspherical lens and at least one lens in the first lens group is an aspherical lens.
4. The lidar receiving optical lens of claim 1, wherein the first lens group comprises a third lens with negative focal power, a fourth lens with positive focal power and a fifth lens with negative focal power, which are sequentially arranged from an object side to an image side, wherein an object side of the third lens is a concave surface, an image side is a concave surface, an object side of the fourth lens is a convex surface, an image side is a convex surface, an object side of the fifth lens is a concave surface, an image side is a concave surface, a focal length of the third lens is f 3, a focal length of the fourth lens is f 4, and a focal length of the fifth lens is f 5, and the following conditions are satisfied: 0.8 < |f 3/f|＜1.4,1.0＜|f3/f4|＜2.6,3.5＜|f5/f| < 3.7.
5. The lidar receiving optical lens of claim 4 wherein the second lens is an aspherical lens and at least two lenses of the first lens group are aspherical lenses.
6. The lidar receiving optical lens of claim 1, wherein the first lens group comprises, in order from the object side to the image side, a third lens having negative optical power, a fourth lens having positive optical power, a fifth lens having negative optical power, and a sixth lens having positive optical power, the object side of the third lens is a concave surface, the image side is a concave surface, the object side of the fourth lens is a convex surface, the image side is a convex surface, the object side of the fifth lens is a convex surface, the image side is a concave surface, at least one of the object side and the image side of the sixth lens is a convex surface, the focal length of the third lens is f 3, the focal length of the fourth lens is f 4, the focal length of the fifth lens is f 5, the focal length of the sixth lens is f 6, and the conditions are satisfied ：0.8＜|f3/f|＜1.7,1.0＜|f3/f4|＜2.6,0.8＜|f5/f|＜1.4,0.8＜|f5/f6|＜1.5.
7. The lidar receiving optical lens of claim 6 wherein the second lens is an aspherical lens and at least two lenses of the first lens group are aspherical lenses.
CN202410399126.4A 2024-04-03 Laser radar receiving optical lens Active CN117991479B (en)

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CN113946033A (en) * 2021-09-28 2022-01-18 江西凤凰光学科技有限公司 High-resolution wide-angle vehicle-mounted laser radar lens
CN116047713A (en) * 2022-12-21 2023-05-02 宁波永新光学股份有限公司 Low temperature drift laser radar receiving lens
CN116299982A (en) * 2023-05-11 2023-06-23 宁波永新光学股份有限公司 Long-focus receiving optical system of low-temperature drift laser radar
WO2023123425A1 (en) * 2021-12-31 2023-07-06 深圳市大疆创新科技有限公司 Camera assembly, image capture apparatus, and movable platform

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101452150B1 (en) * 2013-11-08 2014-10-22 삼성전기주식회사 Lens module
CN111308669A (en) * 2020-04-07 2020-06-19 天津欧菲光电有限公司 Optical imaging lens, image capturing module and electronic device
CN113946033A (en) * 2021-09-28 2022-01-18 江西凤凰光学科技有限公司 High-resolution wide-angle vehicle-mounted laser radar lens
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