Infrared laser radar receiving lens

Abstract

The utility model relates to an infrared laser radar receiving lens, and belongs to the technical field of optical imaging. The infrared laser radar receiving lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and an optical filter which are sequentially arranged from an object side to an image side, the first lens is a convex-concave negative focal power lens; the second lens is a convex-concave negative focal power lens; the third lens is a convex-concave positive focal power lens; the fourth lens is a concave-convex positive focal power lens; the fifth lens is a concave-convex positive focal power lens; and the sixth lens is a convex-concave positive focal power lens. Therefore, the infrared laser radar receiving lens provided by the utility model has the characteristics of small volume, ultra-wide angle, large flux, low distortion, high resolution, strong anti-interference capability and the like.

Description

Technical Field

[0001] The utility model belongs to the technical field of optical imaging, and particularly relates to an infrared laser radar receiving lens. Background Art

[0002] With the vigorous development of science and technology, LiDAR is becoming a booster in the development of human science and technology. The outstanding capabilities of LiDAR in three-dimensional perception applications are becoming more and more well-known in the industry. At present, LiDAR is widely used in equipment such as drones, robots, unmanned vehicles, rail transportation and related fields. LiDAR has the advantages of high precision, long distance, strong reliability and large range. However, existing lenses do not meet the requirements of small size, ultra-wide angle, large flux, low distortion, high resolution and strong anti-interference ability. Utility Model Content

[0003] The utility model provides an infrared laser radar receiving lens, which is used to solve the above technical problems.

[0004] In order to achieve the above-mentioned purpose, the utility model is implemented through the following technical scheme: an infrared laser radar receiving lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a filter arranged in sequence from the object side to the image side; the first lens is a convexoconcave negative optical focal length lens; the second lens is a convexoconcave negative optical focal length lens; the third lens is a convexoconcave positive optical focal length lens; the fourth lens is a concave-convex positive optical focal length lens; the fifth lens is a concave-convex positive optical focal length lens; the sixth lens is a convexoconcave positive optical focal length lens.

[0005] Optionally, the effective focal length of the lens is f, the focal length of the first lens is f1, and f1 and f satisfy -5.0 <f1 / f<0;

[0006] The focal length of the second lens is f2, and f2 and f satisfy -5.0 <f2 / f<0;

[0007] The focal length of the third lens is f3, and f3 and f satisfy 1.0 <f3 / f<10;

[0008] The focal length of the fourth lens is f4, and f4 and f satisfy 1 <f4 / f<4;

[0009] The focal length of the fifth lens is f5, and f5 and f satisfy 2 <f5 / f<8;

[0010] The focal length of the sixth lens is f6, and f6 and f satisfy 2 <f6 / f<8。

[0011] Optionally, when the wavelength of the light wave is 589.3 nm, the refractive index of the first lens is Nd1, and Nd1 satisfies 1.5≤Nd1≤1.9; the refractive index of the second lens is Nd2, and Nd2 satisfies 1.7≤Nd2≤2.1; the refractive index of the third lens is Nd3, and Nd3 satisfies 1.7≤Nd3≤2.1; the refractive index of the fourth lens is Nd4, and Nd4 satisfies 1.7≤Nd3≤2.1; the refractive index of the fifth lens is Nd5, and Nd5 satisfies 1.7≤Nd3≤2.1; the refractive index of the sixth lens is Nd6, and Nd6 satisfies 1.7≤Nd6≤2.1.

[0012] Optionally, when the wavelength of the light wave is 589.3 nm, the Abbe number of the first lens is Vd1, and Vd1 satisfies 20≤Vd1≤65; the Abbe number of the second lens is Vd2, and Vd2 satisfies 20≤Vd2≤65; the Abbe number of the third lens is Vd3, and Vd3 satisfies 20≤Vd3≤65; the Abbe number of the fourth lens is Vd4, and Vd4 satisfies 20≤Vd4≤65; the Abbe number of the fifth lens is Vd5, and Vd5 satisfies 20≤Vd5≤65; the Abbe number of the sixth lens is Vd6, and Vd6 satisfies 20≤Vd6≤65.

[0013] Optionally, the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are all resin spherical lenses.

[0014] Optionally, outer surfaces of the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are all coated.

[0015] Optionally, an infrared laser radar receiving lens further includes a laser radar receiving chip. The laser radar receiving chip is located on the side of the filter away from the sixth lens, the distance from the object side vertex of the first lens to the center of the laser radar receiving chip is TTL, the maximum imaging circle diameter of the lens is MIC, and the TTL and the MIC satisfy -2 <TTL / MIC<5。

[0016] Optionally, an infrared laser radar receiving lens further includes an aperture, and the aperture is arranged between the third lens and the fourth lens.

[0017] It can be seen from the above technical solution that the beneficial effects of the infrared laser radar receiving lens provided by the utility model are:

[0018] The utility model provides an infrared laser radar receiving lens comprising a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a filter. The first lens is a convexo-concave negative focal lens; the second lens is a convexo-concave negative focal lens; the third lens is a convexo-concave positive focal lens; the fourth lens is a concave-convex positive focal lens; the fifth lens is a concave-convex positive focal lens; the sixth lens is a convexo-concave positive focal lens.

[0019] Through the above structure, the infrared laser radar receiving lens provided by the utility model overcomes the requirements of existing lenses such as small size, ultra-wide angle, large flux, low distortion, high resolution, and strong anti-interference ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 A schematic diagram of the structure of an infrared laser radar receiving lens provided in an embodiment of the utility model;

[0022] Figure 2 A schematic diagram of the optical path of an infrared laser radar receiving lens provided in an embodiment of the utility model;

[0023] Figure 3-Figure 9 A light spot performance diagram of an infrared laser radar receiving lens provided by an embodiment of the utility model;

[0024] Fig.10 A field curvature diagram of an infrared laser radar receiving lens provided in an embodiment of the utility model;

[0025] Fig.11 A distortion diagram of an infrared laser radar receiving lens provided in an embodiment of the utility model.

[0026] In the figure: 1-first lens; 2-second lens; 3-third lens; 4-fourth lens; 5-fifth lens; 6-sixth lens; 7-filter; 8-laser radar receiving chip; 9-aperture. DETAILED DESCRIPTION

[0027] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0028] In the description of the present application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0029] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0030] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0031] Example

[0032] At present, LiDAR is widely used in drones, robots, unmanned vehicles, rail transit and other equipment and related fields. LiDAR has the advantages of high precision, long distance, strong reliability and large range. However, existing lenses do not meet the requirements of small size, ultra-wide angle, large flux, low distortion, high resolution and strong anti-interference ability.

[0033] In order to solve the above technical problems, the present embodiment provides an infrared laser radar receiving lens including a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6 and a filter 7 arranged in sequence from the object side to the image side; the first lens 1 is a convex-concave negative optical focal length lens; the second lens 2 is a convex-concave negative optical focal length lens; the third lens 3 is a convex-concave positive optical focal length lens; the fourth lens 4 is a concave-convex positive optical focal length lens; the fifth lens 5 is a concave-convex positive optical focal length lens; the sixth lens 6 is a convex-concave positive optical focal length lens.

[0034] Through the above structure, this embodiment overcomes the shortcomings of the existing lens and provides a lens with small size, ultra-wide angle, large throughput, low distortion, high resolution and strong anti-interference ability.

[0035] On the above basis, the effective focal length of the lens is f, the focal length of the first lens 1 is f1, and f1 and f satisfy -5.0 < f1 / f < 0. The focal length of the second lens 2 is f2, and f2 and f satisfy -5.0 < f2 / f < 0. The focal length of the third lens 3 is f3, and f3 and f satisfy 1.0 < f3 / f < 10. The focal length of the fourth lens 4 is f4, and f4 and f satisfy 1 < f4 / f < 4. The focal length of the fifth lens 5 is f5, and f5 and f satisfy 2 < f5 / f < 8. The focal length of the sixth lens 6 is f6, and f6 and f satisfy 2 < f6 / f < 8. The focal length of a lens refers to the degree of convergence or divergence of light rays passing through the lens. The magnitude of the focal length is related to the shape and refractive index of the lens. For a thin lens, the focal length can be calculated based on the curvature radius and refractive index of the lens.

[0036] On the above basis, when the wavelength of the light wave is 589.3 nm, the refractive index of the first lens 1 is Nd1, and Nd1 satisfies 1.5 ≤ Nd1 ≤ 1.9; the refractive index of the second lens 2 is Nd2, and Nd2 satisfies 1.7 ≤ Nd2 ≤ 2.1; the refractive index of the third lens 3 is Nd3, and Nd3 satisfies 1.7 ≤ Nd3 ≤ 2.1; the refractive index of the fourth lens 4 is Nd4, and Nd4 satisfies 1.7 ≤ Nd4 ≤ 2.1; the refractive index of the fifth lens 5 is Nd5, and Nd5 satisfies 1.7 ≤ Nd5 ≤ 2.1; the refractive index of the sixth lens 6 is Nd6, and Nd6 satisfies 1.7 ≤ Nd6 ≤ 2.1.

[0037] It should be noted that a light wave with a wavelength of 589.3 nm is generally referred to as D light or ordinary light. The refractive index of a light wave refers to the ratio of the speed of light when propagating in different media. The refractive index is usually denoted by the symbol n. When light propagates from one medium to another medium with a different refractive index, the propagation direction of the light ray will be deflected. This is caused by the different propagation speeds of light in different media.

[0038] The calculation formula for the refractive index is

[0039] n = c / v

[0040] where n is the refractive index, c is the speed of light in a vacuum (about 3.00×10^8 m / s), and v is the propagation speed of light in the medium. The magnitude of the refractive index determines the propagation speed of light in the medium and the degree of change in the propagation direction. When light propagates from a medium with a higher refractive index to a medium with a lower refractive index, the light ray will be deflected towards the normal direction; on the contrary, when light propagates from a medium with a lower refractive index to a medium with a higher refractive index, the light ray will be deflected away from the normal direction.

[0041] On the basis of the above, when the wavelength of the light wave is 589.3nm, the Abbe number of the first lens 1 is Vd1, and Vd1 satisfies 20≤Vd1≤65; the Abbe number of the second lens 2 is Vd2, and Vd2 satisfies 20≤Vd2≤65; the Abbe number of the third lens 3 is Vd3, and Vd3 satisfies 20≤Vd3≤65; the Abbe number of the fourth lens 4 is Vd4, and Vd4 satisfies 20≤Vd4≤65; the Abbe number of the fifth lens 5 is Vd5, and Vd5 satisfies 20≤Vd5≤65; the Abbe number of the sixth lens 6 is Vd6, and Vd6 satisfies 20≤Vd6≤65.

[0042] It should be noted that the Abbe number of light waves is a physical quantity used to describe the dispersion properties of materials. The larger the Abbe number, the smaller the dispersion of the material, that is, the smaller the difference in refractive index of light of different wavelengths in the material. On the contrary, the smaller the Abbe number, the greater the dispersion of the material, and the greater the difference in refractive index of light of different wavelengths in the material.

[0043] On the basis of the above, the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5 and the sixth lens 6 are all resin spherical lenses.

[0044] It should be noted that resin spherical lenses are a type of eyeglass lens material, usually made of resin material and designed with spherical curvature. Compared with glass lenses, resin spherical lenses are lighter and less likely to break, making them suitable for people who need to wear glasses. This type of lens can be used for different types of vision problems such as myopia, hyperopia, and astigmatism. When purchasing resin spherical lenses, it is generally necessary to select appropriate lens parameters based on personal vision conditions and the advice of opticians to obtain the best vision correction effect.

[0045] On the basis of the above, outer surfaces of the first lens 1 , the second lens 2 , the third lens 3 , the fourth lens 4 , the fifth lens 5 and the sixth lens 6 are all coated.

[0046] It should be specifically noted that the coating of the infrared laser radar receiving lens is very important. It can improve the transmittance of the receiving lens, reduce the reflectivity, improve the receiving efficiency, and reduce energy loss. Common coating methods include single-layer coating, multi-layer coating, anti-reflective coating, etc. The specific coating method to be selected depends on the specific needs and application scenarios. In the field of infrared laser radar, the application of coating technology can improve the performance and stability of the laser radar system.

[0047] On the basis above, an infrared lidar receiving lens further includes a lidar receiving chip 8. The lidar receiving chip 8 is located on the side of the filter 7 away from the sixth lens 6. The distance from the vertex of the object side of the first lens 1 to the center of the lidar receiving chip is TTL, and the maximum imaging circle diameter of the lens is MIC. TTL and MIC satisfy -2 < TTL / MIC < 5. The lidar receiving chip is the core component in the lidar system, which is used to receive the laser signal emitted by the lidar and convert it into an electrical signal for processing. The lidar receiving chip usually includes functional modules such as a laser receiver, a signal amplifier, a filter, and an analog-to-digital converter to achieve efficient reception and processing of the laser signal. The performance of the lidar receiving chip directly affects the performance of the entire lidar system, including indicators such as reception sensitivity, signal-to-noise ratio, and dynamic range.

[0048] On the basis above, an infrared lidar receiving lens further includes a diaphragm 9. The diaphragm 9 is arranged between the third lens 3 and the fourth lens 4. The diaphragm mainly controls the incident angle of light, controls the size and shape of light, and reduces the scattering and interference of the optical system.

[0049] Figures 3 to 9 It is a spot performance diagram for different image plane sizes and different object plane angles in the infrared lidar receiving lens.

[0050] Fig.10 It is a schematic diagram of the field curvature of the infrared lidar receiving lens, where the abscissa is the field value and the ordinate is the image height value; within the full field of view, the field curvature is within 0.09 mm. The optical structure is relatively simple, with high resolution, small distortion, and high relative illumination.

[0051] Fig.11 It is a schematic diagram of the lens distortion performance. It can be seen that the abscissa is the distortion value and the ordinate is the image height value; under the full field of view, 0% < distortion value < 0.9%.

[0052] As shown in the above optical analysis diagram, the optical system has high imaging resolution, very small distortion, high transmittance, and a wide shooting angle.

[0053] From the above, it can be seen that the infrared laser radar receiving lens provided by the utility model, the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, and the sixth lens 6 are all spherical resin lenses. While meeting the requirements of lens imaging clarity and optimal color performance, it is also simpler and has good light transmittance; the lens is made of professional optical resin and glass materials, which can ensure that under a working environment of -40℃ to 80℃, by reasonably giving the curvature radius and center thickness of the lens, the change in temperature drift is minimized, so that the temperature change has basically no effect on the imaging pixels of the imaging system. Therefore, the problem that the existing technology does not have small size, ultra-wide angle, large flux, low distortion, high resolution, and strong anti-interference ability is overcome.

[0054] The above is only a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope recorded in the utility model, which should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. An infrared laser radar receiving lens, characterized in that: include: A first lens (1), a second lens (2), a third lens (3), a fourth lens (4), a fifth lens (5), a sixth lens (6) and a filter (7) are arranged in sequence from the object side to the image side; The first lens (1) is a convex-concave negative power lens; The second lens (2) is a convex-concave negative power lens; The third lens (3) is a convex-concave positive focal length lens; The fourth lens (4) is a meniscus lens with positive focal length; The fifth lens (5) is a meniscus lens with positive focal length; The sixth lens (6) is a convex-concave lens with positive focal length.

2. The infrared laser radar receiving lens according to claim 1, characterized in that: The effective focal length of the lens is f, the focal length of the first lens (1) is f1, and f1 and f satisfy -5.0 <f1 / f<0; The focal length of the second lens (2) is f2, and f2 and f satisfy -5.0 <f2 / f<0; The focal length of the third lens (3) is f3, and the relationship between f3 and f satisfies 1.

0. <f3 / f<10; The focal length of the fourth lens (4) is f4, and f4 and f satisfy 1 <f4 / f<4; The focal length of the fifth lens (5) is f5, and f5 and f satisfy 2 <f5 / f<8; The focal length of the sixth lens (6) is f6, and f6 and f satisfy 2 <f6 / f<8。 3. The infrared laser radar receiving lens according to claim 2, characterized in that: When the wavelength of the light wave is 589.3 nm, the refractive index of the first lens (1) is Nd1, and Nd1 satisfies 1.5≤Nd1≤1.9; The refractive index of the second lens (2) is Nd2, and Nd2 satisfies 1.7≤Nd2≤2.1; The refractive index of the third lens (3) is Nd3, and Nd3 satisfies 1.7≤Nd3≤2.1; The refractive index of the fourth lens (4) is Nd4, and Nd4 satisfies 1.7≤Nd4≤2.1; The refractive index of the fifth lens (5) is Nd5, and Nd5 satisfies 1.7≤Nd5≤2.1; The refractive index of the sixth lens (6) is Nd6, and Nd6 satisfies 1.7≤Nd6≤2.

1.

4. The infrared laser radar receiving lens according to claim 3, characterized in that: When the wavelength of the light wave is 589.3 nm, the Abbe number of the first lens (1) is Vd1, and Vd1 satisfies 20≤Vd1≤65; The Abbe number of the second lens (2) is Vd2, and Vd2 satisfies 20≤Vd2≤65; The Abbe number of the third lens (3) is Vd3, and Vd3 satisfies 20≤Vd3≤65; The Abbe number of the fourth lens (4) is Vd4, and Vd4 satisfies 20≤Vd4≤65; The Abbe number of the fifth lens (5) is Vd5, and Vd5 satisfies 20≤Vd5≤65; The Abbe number of the sixth lens (6) is Vd6, and Vd6 satisfies 20≤Vd6≤65.

5. The infrared laser radar receiving lens according to claim 4, characterized in that: The first lens (1), the second lens (2), the third lens (3), the fourth lens (4), the fifth lens (5) and the sixth lens (6) are all resin spherical lenses.

6. The infrared laser radar receiving lens according to claim 5, characterized in that: The outer surfaces of the first lens (1), the second lens (2), the third lens (3), the fourth lens (4), the fifth lens (5) and the sixth lens (6) are all coated.

7. The infrared laser radar receiving lens according to claim 1, characterized in that: Also includes: A laser radar receiving chip (8), wherein the laser radar receiving chip (8) is located on a side of the filter (7) away from the sixth lens (6), the distance from the object side vertex of the first lens (1) to the center of the laser radar receiving chip is TTL, the maximum imaging circle diameter of the lens is MIC, and the TTL and the MIC satisfy -2 <TTL / MIC<5。 8. The infrared laser radar receiving lens according to claim 7, characterized in that: Also includes: The aperture (9) is arranged between the third lens (3) and the fourth lens (4).

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