Lidar Scanning Mirror and Diffractive Element Rotation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing lidar scanning systems require complex control and multiple components to achieve 360° scanning, which is inefficient and prone to technical issues, especially in applications like self-driving vehicles that need detailed 3D mapping without rotating the device body.
Innovation Solution
A method utilizing a rotating angled scanning mirror and diffractive or refractive optical elements to achieve 360° scanning with minimal moving components, allowing for simple control and dense scanning patterns using a single or few laser sources and emission beam paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a typical lidar scanning system uses a rotating mirror with the emission beam path coincident with the rotation axis, then the beam is scanned in a detecting plane, but the scanning is limited to a single plane and cannot achieve 360° volumetric scanning
Solution Approach 1:
The invention introduces a second rotational degree of freedom by mounting the entire mirror assembly on a rotating platform. The first mirror rotates about the emission beam axis (first dimension), while the platform rotates the entire assembly about a vertical axis (second dimension), transforming single-plane scanning into 360° volumetric scanning.
Solution Approach 2:
The scanning function is divided between two independent rotational movements: the fast scanning mirror handling azimuthal scanning within a plane, and the slow rotating platform handling elevation scanning across 360°. This segmentation allows each component to perform its function independently without interfering with the other.
2Measurement precision
If multiple laser sources or split beams are used to achieve dense scanning, then scanning density improves, but device complexity and control requirements increase
Solution Approach 1:
The invention uses dynamic control of the scanning mirror's rotational speed to achieve variable scanning density. By rotating the mirror faster when scanning across open areas and slower when scanning across features of interest, the system achieves uniform point distribution and dense scanning of important regions using a single laser source.
Solution Approach 2:
The scanning system uses periodic rotation of the mirror at controlled speeds to sweep the laser beam across the field of view. The periodic nature of the rotation, combined with synchronized detection, allows for systematic coverage and dense sampling of the environment.
3Adaptability or versatility
If the device body is rotated to achieve 3D mapping, then complete 3D coverage is obtained, but the system becomes less suitable for mobile applications like self-driving vehicles
Solution Approach 1:
The invention extracts the scanning function from the device body itself. Instead of rotating the entire vehicle or device housing, only lightweight internal components (mirrors and platform) are rotated, allowing the main device body to remain stationary and easily integrable into mobile platforms.
Solution Approach 2:
The invention replaces the mechanical approach of rotating the entire device body with an optical scanning approach using rotating mirrors and platforms. This substitution maintains 3D mapping capability while dramatically reducing the mechanical complexity and inertia associated with rotating the entire device.
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
Enables detailed 360° scanning with reduced complexity and component movement, improving scanning density and efficiency, particularly suitable for applications requiring precise 3D mapping without rotating the device body.
Implementation Method 1
rotating a first diffractive or refractive optical element (DROE) at a second angular velocity about a second axis of rotation
Implementation Method 2
rotating a first diffractive or refractive optical element (DROE) at a second angular velocity about a second axis of rotation
Implementation Method 3
rotating an angled scanning mirror at a first angular velocity about a first axis of rotation
Implementation Method 4
the time that it takes a pulse of light to be reflected from an object and returned to a receiver after it has been emitted is used to calculate the distance
Implementation Method 5
controlling a stationary laser source to emit light along an emission beam path
Data Source
AI summary
A method of lidar scanning over a rotational range provides a dense scanning pattern over the entire rotational range without the need for complex control of components. The method comprises rotating an angled scanning mirror at a first angular velocity about an axis of rotation; rotating a first diffractive or refractive optical element at a second angular velocity about the axis of rotation; controlling a stationary laser source to emit light along an emission beam path that passes through the first diffractive optical element before being incident upon the scanning mirror in order to reflect said light onto a scanning beam path; and detecting light reflected from external objects present in the scanning beam path.