Acousto-optical LiDAR Beam Deflection for High Speed Large Aperture

Solution Overview

Problem

Conventional LiDAR receivers face a trade-off between high scanning speed and large receiving aperture, as small rotational mirrors enable high speed but limit detection distance, while large mirrors reduce scanning speed and refresh rate.

Innovation Solution

The implementation of an acousto-optical (AO) beam deflecting unit that generates a diffraction grating along an acoustic wave's propagating direction to deflect laser beams, allowing for high-speed scanning with a larger aperture without the size limitations of traditional rotational mirrors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a small rotational mirror is used, then scanning speed is improved, but receiving aperture is reduced

Engineering Contradiction:

Improvescanning speedVSAvoidreceiving aperture

Core Design Contradiction:

SpeedVSArea of stationary object

Solution Approach 1:

The patent replaces the mechanical rotational mirror system with an acousto-optical beam deflecting unit. This unit uses acoustic waves to create a moving diffraction grating that deflects laser beams without mechanical moving parts, thereby achieving high scanning speed while maintaining a large receiving aperture. The acoustic wave frequency can be rapidly changed to steer the beam, eliminating the mechanical inertia limitations of rotational mirrors.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the operating parameters by using acoustic wave frequency and amplitude to control beam deflection instead of mechanical rotation speed and mirror size. By adjusting the acoustic frequency, the diffraction angle changes dynamically, enabling fast scanning. The physical size of the acousto-optical unit can be made large to provide a big aperture while the acoustic wave provides rapid scanning capability.

Inventive Principle:

Principle #35Parameter changes

2Area of stationary object

If a large rotational mirror is used, then receiving aperture is improved, but scanning speed is reduced

Engineering Contradiction:

Improvereceiving apertureVSAvoidscanning speed

Core Design Contradiction:

Area of stationary objectVSSpeed

Solution Approach 1:

The patent replaces the mechanical rotational mirror system with an acousto-optical beam deflecting unit. This unit uses acoustic waves to create a moving diffraction grating that deflects laser beams without mechanical moving parts, thereby achieving high scanning speed while maintaining a large receiving aperture. The acoustic wave frequency can be rapidly changed to steer the beam, eliminating the mechanical inertia limitations of rotational mirrors.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the operating parameters by using acoustic wave frequency and amplitude to control beam deflection instead of mechanical rotation speed and mirror size. By adjusting the acoustic frequency, the diffraction angle changes dynamically, enabling fast scanning. The physical size of the acousto-optical unit can be made large to provide a big aperture while the acoustic wave provides rapid scanning capability.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution enables improved light energy collection and detection distance while maintaining high scanning speed, using a smaller AO beam deflecting unit that dynamically adjusts the refractive index with acoustic signals, allowing for precise deflection of laser beams to a smaller sensing area.

Implementation Method 1

The AO beam deflecting unit is configured to generate a diffraction grating along a propagating direction of an acoustic wave, receive the input laser beam such that the input laser beam impinges upon the diffraction grating, and form an output laser beam towards the beam sensor

Methodology Applied

Scientific EffectAcousto-optic effect: Acousto-optic Effect

Data Source

PatentUS12055663B2Acousto-optical beam deflecting unit for light detection and ranging (LiDAR)

Publication Date: 2024.08.06 BEIJING VOYAGER TECH CO LTD

AI summary

Embodiments of the disclosure provide receivers for light detection and ranging (LiDAR). In an example, a receiver includes an acousto-optical (AO) beam deflecting unit configured to receive an input laser beam and a controller configured to cause an acoustic signal to be applied to the AO beam deflecting unit to deflect the input laser beam for a deflection angle and form an output laser beam towards a beam sensor. The deflection angle between the input and the output laser beams is nonzero.