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CN-121348583-B - Infrared collimation lens of laser radar

CN121348583BCN 121348583 BCN121348583 BCN 121348583BCN-121348583-B

Abstract

The application provides an infrared collimating lens of a laser radar, which sequentially comprises a first lens with negative focal power, a second lens with positive focal power, a third lens with negative focal power, a fourth lens with positive focal power and a fifth lens with positive focal power from an object side to an image side along an optical axis, wherein all lenses are spherical glass lenses, so that the reliability of the lens is greatly improved, the focal power and the surface shape of each lens are reasonably distributed, the correction of various optical aberrations is realized, and laser including the whole C wave band (1530 nm-1565 nm) can be collimated, and a better collimating effect can be obtained.

Inventors

  • JIANG WENCHAO
  • Gong Hongruo
  • SHAN ZIHAO
  • HUANG JINXI

Assignees

  • 杭州视光半导体科技有限公司

Dates

Publication Date
20260505
Application Date
20251218

Claims (9)

  1. 1. An infrared collimating lens of a laser radar, comprising, in order from an object side to an image side along an optical axis: The lens system comprises a first lens with negative focal power, a second lens with positive focal power, a third lens with negative focal power, a fourth lens with positive focal power, a fifth lens with positive focal power, a third lens with negative focal power, a fourth lens with positive focal power, a third lens with positive focal power, a fourth lens with negative focal power, a fifth lens with positive focal power, a third lens with positive focal power, a fourth lens with positive focal power, a fifth lens with positive focal power, a third lens with positive focal power, a fourth lens with positive focal power, a third lens with a positive focal length of-167.24 mm, a third lens with a positive focal length of-6.02 mm, a fourth lens with a positive focal length of-30.09 mm, a third lens with a positive focal length of-11.32 mm, a third lens with a third focal length of-167.24 mm; The first lens, the second lens, the third lens, the fourth lens and the fifth lens are all spherical glass lenses, a diaphragm is arranged between the second lens and the third lens, the axial distance from the object side surface of the first lens to the image plane of the infrared collimating lens is TTL, and the infrared collimating lens meets the requirements that TTL is 30 mm <35 mm.
  2. 2. The infrared collimating lens of claim 1, wherein the infrared collimating lens collimates and transmits a beam of light from a lidar to an external object and receives light returned by the external object for transmission to the lidar.
  3. 3. The infrared collimator lens of claim 1, wherein the first lens has a center thickness CT1 and an edge thickness ET1 on the optical axis, and the first lens satisfies CT1/ET1>0.35.
  4. 4. The infrared collimator lens of claim 1, wherein the second lens has a center thickness CT2 and an edge thickness ET2 on the optical axis, and the second lens satisfies ET2/CT2>0.35.
  5. 5. The infrared collimator lens of claim 1, wherein the third lens has a center thickness of CT3 and an edge thickness of ET3 on an optical axis, the fourth lens has a center thickness of CT4 and an edge thickness of ET4 on an optical axis, the fifth lens has a center thickness of CT5 and an edge thickness of ET5 on an optical axis, and the third lens, the fourth lens and the fifth lens satisfy 0.8< (CT3+CT4+CT5)/(ET 3+ET 4+CT5) <1.4.
  6. 6. The infrared collimating lens of claim 1, wherein the effective focal length of the second lens is f2, the total effective focal length of the infrared collimating lens is f, and the infrared collimating lens satisfies-2 < f2/f <2.
  7. 7. The infrared collimator lens of claim 1, wherein the effective focal length of the infrared collimator lens is f, and the infrared collimator lens satisfies 14 mm < f <18 mm.
  8. 8. The infrared collimator of claim 1, wherein an on-axis distance from the object side surface of the first lens to the image side surface of the fifth lens is TD, a sum of air intervals on an optical axis between any two adjacent lenses of the first lens to the fifth lens is Σat, and the infrared collimator satisfies 1.5< TD/Σat <3.
  9. 9. A light transmission method applied to the infrared collimating lens according to any one of claims 1 to 8, comprising: When the light beam is transmitted to an external object by the laser radar, the light beam sequentially passes through the fifth lens and the fourth lens to be converged, and diverges through the third lens so that the light beam passes through the diaphragm, and after the light beam passes through the diaphragm, the light beam is converged through the second lens, diverged through the first lens and transmitted to the external object; when the light beam is transmitted to the laser radar by the external object, the light beam diverges through the first lens and converges through the second lens, so that the light beam converges at the diaphragm, diverges through the third lens after passing through the diaphragm, and sequentially converges through the fourth lens and the fifth lens to be transmitted to the laser radar.

Description

Infrared collimation lens of laser radar Technical Field The application belongs to the field of laser radars, relates to a laser radar collimating lens technology, and particularly relates to an infrared collimating lens of a laser radar. Background The collimating lens is used as a key optical component of the laser radar, has great influence on the collimating quality and the echo collecting efficiency of the laser beam, and further has great influence on the ranging accuracy and the reliability of the laser radar. At present, the laser radar usually adopts an infrared band, particularly a C band (1530nm-1565 nm), and has excellent atmospheric penetrability and human eye safety characteristics, so that the laser radar becomes a preferable band of a laser radar system. Based on this, the collimating lens of current lidar is generally required to be suitable for the infrared band. The existing infrared collimating lens mostly adopts a plastic or glass-plastic mixed lens. However, plastic lenses have problems of poor thermal stability, easy aging, and the like, are prone to thermal defocusing when temperature changes, are difficult to maintain stable performance under wide temperature working conditions, and are limited in long-term reliability. However, since the processing difficulty of the glass aspherical lens is high, the glass lens is generally a spherical lens, and the aberration is high compared with the aspherical lens. Therefore, there is a need to design a novel infrared collimating lens with high stability and excellent performance in the C-band, so as to improve the reliability and adaptability of the laser radar in a complex environment and meet the outdoor use requirement of the laser radar. Disclosure of Invention The application aims to provide an infrared collimating lens which is used for solving the problems that no infrared collimating lens with higher reliability and collimation performance is available at present and is applied to a laser radar using C-band (1530 nm-1565 nm) laser. In a first aspect, the application provides an infrared collimating lens of a laser radar, which sequentially comprises a first lens with negative focal power, a second lens with positive focal power, a third lens with negative focal power, a fourth lens with positive focal power and a fifth lens with positive focal power from an object side to an image side along an optical axis, wherein the first lens, the second lens, the third lens, the fourth lens and the fifth lens are all spherical glass lenses. In an embodiment of the present application, an on-axis distance from the object side surface of the first lens to an image plane of the infrared collimating lens is TTL, and the infrared collimating lens satisfies 30 mm < TTL <35 mm. In an embodiment of the present application, the infrared collimating lens collimates and transmits a light beam from the laser radar to an external object, and receives light returned from the external object and transmits the light beam to the laser radar. In an embodiment of the application, the object side surface of the first lens is a convex surface, the image side surface of the first lens is a concave surface, the center thickness of the first lens on the optical axis is CT1, the edge thickness of the first lens is ET1, and the first lens satisfies that CT1/ET1 is more than 0.35. In an embodiment of the application, the object side surface of the second lens is a convex surface, the image side surface of the second lens is a concave surface, the center thickness of the second lens on the optical axis is CT2, the edge thickness of the second lens is ET2, and the second lens satisfies that ET2/CT2 is more than 0.35. In an embodiment of the application, the object side surface and the image side surface of the third lens element are concave, the center thickness of the third lens element on the optical axis is CT3, the edge thickness of the third lens element is ET3, the object side surface of the fourth lens element is concave, the image side surface of the fourth lens element is convex, the center thickness of the third lens element on the optical axis is CT4, the edge thickness of the fourth lens element is ET4, the object side surface and the image side surface of the fifth lens element are convex, the center thickness of the third lens element on the optical axis is CT5, the edge thickness of the third lens element is ET5, and the third lens element, the fourth lens element and the fifth lens element satisfy (CT3+CT4+CT5)/(ET 3+ET 4+CT5) <1.4. In an embodiment of the present application, the effective focal length of the second lens is f2, the total effective focal length of the infrared collimating lens is f, and the infrared collimating lens satisfies-2 < f2/f <2. In an embodiment of the present application, the effective focal length of the infrared collimating lens is f, and the infrared collimating lens satisfies 14 mm < f <18 mm. In an embodiment of the present a