Large-range scanning coaxial MEMS laser radar optical system

Abstract

The invention discloses a large-range scanning coaxial MEMS laser radar optical system, comprising a collimating laser, a one-dimensional MEMS galvanometric scanner, a reflecting mirror, a rotating mirror, a driving motor and a receiving end; the collimating laser and the one-dimensional MEMS galvanometric scanner are arranged on the same straight line; the reflecting mirror, the rotating mirror and the one-dimensional MEMS galvanometric scanner are arranged on the same straight line in another direction; the straight line where the collimating laser and the one-dimensional MEMS galvanometricscanner are located is angularly intersected with the straight line where the reflecting mirror, the rotating mirror and the one-dimensional MEMS galvanometric scanner are located; the receiving end and the reflecting mirror are arranged on the same straight line, and the straight line where the receiving end and the reflecting mirror are located is angularly intersected with the straight line where the reflecting mirror, the rotating mirror and the one-dimensional MEMS galvanometric scanner are located; and the driving motor is mounted below the rotating mirror. The system disclosed by the invention does not use a semi-transparent semi-reflection mirror, and energy loss is low; in a receiving light path, wasted energy is also relatively little; and a manner that the one-dimensional MEMS galvanometric scanner and the rotating mirror are combined is adopted, so that a scanning angle of a laser radar in the horizontal direction is greatly increased while centralized energy of a light beam is guaranteed.

Description

technical field [0001] The invention relates to a large-scale scanning coaxial MEMS laser radar optical system, which belongs to the technical fields of optics and laser radar. Background technique [0002] Lidar realizes the ranging function through the time difference between the emitted laser and the received echo signal. At present, there are more and more laser radars that realize two-dimensional scanning through MEMS micromirrors. This type of laser radar generally uses the following methods to achieve two-dimensional scanning. Scanning: use one-dimensional MEMS galvanometer combined with one-dimensional optical magnifying element to achieve; use two one-dimensional MEMS galvanometers to drive synchronously to achieve two-dimensional scanning; use two-dimensional MEMS galvanometer to achieve two-dimensional scanning. In addition, some MEMS lidars have completely separate transmitting optical paths and receiving optical paths, and some adopt the form of coaxial transmit...

AI Technical Summary

Problems solved by technology

[0003] Chinese invention patent CN107219532A discloses a three-dimensional laser radar and a ranging method based on a MEMS micro-scanning mirror, using a single-axis MEMS micro-mirror in conjunction with an optical element with a one-dimensional magnification function to realize two-dimensional scanning, and using a linear detection unit The composed photodetector realizes the laser echo detection. The main problem of this scheme is that the optical element with one-dimensional amplification function shapes the laser light into a line spot, which causes energy dispersion, so long-distance measurement cannot be carried out.

[0004] Chinese invention patent CN 109709572A discloses a semi-coaxial optical path receiving laser radar system, which uses two one-dimensional MEMS vibrating mirrors whose vibration planes are perpendicular to each other to drive synchronously to realize two-dimensional scanning at the transmitting end, and the reflected light passes through the second one-dimensional The MEMS galvanometer and the half-mirror are received by the receiving system. The main disadvantage of this scheme is that the area of ​​the second one-dimensional MEMS galvanometer is relatively large. Such a MEMS galvanometer is difficult to control and high in cost. Axial optical path, the light beam has to pass through the half-transparent mirror twice from emission to reception, and the energy loss is large

[0005] Chinese invention patent CN109239693A discloses a common path scanning laser radar for transmitting and receiving, which uses a two-dimensional MEMS vibrating mirror to realize two-dimensional scanning. The two schemes have the same problem. The light beam has to pass through the half-mirror twice from emission to reception, and the loss of light energy is large. In addition, the scanning angle of the two-dimensional MEMS vibrating mirror is small, and it is difficult to achieve large-scale scanning.

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