Mirrorless Solid-State LiDAR Scanning for Higher Angular Resolution
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Solution Overview
Problem
Conventional LiDAR devices with MEMS mirrors suffer from lower angular resolution due to larger remaining divergent angles of collimated laser beams, which affects their imaging efficiency.
Innovation Solution
A mirrorless LiDAR device employs a shifting mechanism to move a lens array or a laser beam emitting unit, utilizing a modularized component with stacked submount-based edge emitting lasers and a dynamic spatial filter to reduce noise and improve scanning precision, eliminating the need for MEMS mirrors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a MEMS mirror is used to scan linear laser beams, then the scanning function is achieved, but the angular resolution deteriorates due to large remaining divergent angles
Solution Approach 1:
The patent removes the MEMS mirror from the system entirely, extracting the problematic component that causes beam divergence. Instead of using a scanning mirror, the invention employs a fixed lens array combined with sequentially activated edge-emitting lasers to achieve scanning without introducing additional divergent angles, thereby resolving the contradiction between scanning capability and angular resolution.
Solution Approach 2:
The patent replaces the mechanical MEMS mirror scanning system with an electronic control system that sequentially activates multiple edge-emitting lasers. This substitution eliminates the mechanical scanning component that causes beam divergence while maintaining the scanning function through electronic timing control of laser activation, thus improving angular resolution without sacrificing scanning capability.
2Volume of moving object
If a small MEMS mirror (2-3 mm diameter) is used, then the device size is reduced, but the collimated linear laser beams exhibit large remaining divergent angles
Solution Approach 1:
The patent extracts and removes the MEMS mirror component entirely from the system. By eliminating the mirror, the invention avoids the fundamental limitation where small mirror size necessarily results in large beam divergent angles. The scanning function is achieved through a different mechanism that does not suffer from this geometric constraint.
Solution Approach 2:
The patent uses multiple edge-emitting lasers arranged in arrays to create multiple beam paths that replicate the scanning function. Instead of relying on a single small mirror to deflect one beam, the system uses multiple laser sources that can be sequentially activated to produce the same scanning effect without the beam divergence problems associated with small mirrors.
3Productivity
If linear laser beams are used for illumination, then scanning efficiency is improved, but angular resolution deteriorates due to etendue constraints
Solution Approach 1:
The patent segments the laser source into multiple edge-emitting lasers arranged in arrays, with each laser corresponding to a specific beam path. This segmentation allows the system to maintain efficient linear beam scanning while improving angular resolution by having dedicated laser sources for different angular positions, thereby eliminating the etendue-related divergence issues.
Solution Approach 2:
The patent introduces dynamic control through sequential activation of multiple edge-emitting lasers. By dynamically switching which laser is active at any given moment, the system achieves efficient scanning coverage while maintaining tight beam divergence for each individual beam, thus resolving the contradiction between scanning efficiency and angular resolution.
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 approach enhances the angular resolution and signal-to-noise ratio of LiDAR imaging by precisely controlling the scanning directions of laser beams, resulting in denser point clouds within the field of view.
Implementation Method 1
The shifting device can be a piezoelectric actuator
Data Source
AI summary
A mirrorless light detection and ranging (LiDAR) device does not include any microelectromechanical system (MEMS) mirror. Instead, the LiDAR device uses a shifting device to shift a lens array or a laser beam emitting unit, or uses shifting devices to shift both a lens array and a laser beam emitting unit to cause relative motion between the laser beam emitting unit and the lens array. The laser beam emitting unit is a modularized component that includes multiple layers of submount-based edge emitting lasers (EELs) stacked in a staircase manner. Each time the lens array or the laser beam emitting unit changes position, the EELs are activated, one at a time, in a zigzagging sequence across the multiple layers to emit laser beams, with the laser beams emitted from an activation sequence filling up gaps between laser beams emitted from a previous activation sequence. A dynamic spatial filter including segmented areas with a one-to-one correspondence to the EELs in the laser beam emitting unit can be used to reduce noise.