LiDAR Mirror Rotation Optical System Eliminates Rotary Joint

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Solution Overview

Problem

Conventional 360° LiDAR scanners require electrical rotary joints for power transmission, leading to durability and reliability issues, high costs, and limited price reduction due to physical contact and complex configurations.

Innovation Solution

An optical system using mirror rotation with integrated light transmitting and receiving parts, eliminating the need for an electrical rotary joint by arranging the light source, light receiving lens, and motor on a single block, allowing 360° scanning with a simplified and miniaturized structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional 360° LiDAR scanner uses an electrical rotary joint for power transmission to the rotating body, then the scanning function is achieved, but the durability and reliability deteriorate due to physical contact wear

Engineering Contradiction:
Improvedurability of optical systemVSAvoidcomplex configuration of electrical rotary joint
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and removes the electrical rotary joint from the system by redesigning the optical path. The light source and detector are positioned on the stationary housing, and optical components (mirrors, lenses) on the rotating body redirect light through hollow shafts without requiring electrical power transmission to the rotating part. This eliminates the harmful electrical rotary joint while preserving the scanning function.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/electrical power transmission system with an optical system. Instead of transmitting electrical power mechanically to the rotating body, the system uses optical paths through hollow shafts to enable the rotating body to scan without electrical connections, substituting a mechanical system with an optical one that avoids wear and reliability issues.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If a conventional 360° LiDAR scanner includes an electrical rotary joint, then power transmission is enabled, but the cost increases and price reduction is limited

Engineering Contradiction:
Improvemanufacturing costVSAvoidreliability of scanned data
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent extracts the expensive electrical rotary joint from the system architecture. By positioning power-consuming components (light source, detector) on the stationary housing and using optical pathways through hollow rotating shafts, the system eliminates the need for costly electrical power transmission mechanisms, thereby reducing manufacturing cost while maintaining scanning reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent substitutes the expensive mechanical electrical rotary joint with a simpler optical transmission system through hollow shafts. This replacement dramatically reduces manufacturing costs while improving reliability, as the optical system has no moving electrical contacts that wear out or fail.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Volume of moving object

If a conventional 360° LiDAR scanner uses a body rotation method, then 360° scanning is achieved, but the entire size increases and miniaturization becomes difficult

Engineering Contradiction:
Improveentire size of scannerVSAvoidinstallation on small mobile object
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

The patent segments the LiDAR system into two distinct parts: a stationary housing containing power-consuming components (light source, detector, processing units) and a lightweight rotating body containing only optical scanning components (mirrors, lenses). This segmentation allows the rotating body to be miniaturized for easy installation on small mobile objects while the stationary housing provides stable power and processing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a single rotating body design to a two-dimensional configuration with stationary and rotating components separated in space. The stationary housing provides a stable base while the rotating body performs scanning, allowing the system to be scaled down for small mobile objects while maintaining 360° scanning capability through the separated architecture.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

The system achieves miniaturization, cost-effectiveness, and easy installation on small mobile objects while performing 360° scanning without an electrical rotary joint, enhancing durability and reliability.

Implementation Method 1

a first mirror configured to form a predetermined first angle with a horizontal surface... allow the pulse laser to advance to a measurement target by passing through the first hollow hole

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

a second mirror to be rotated with the first mirror and so arranged as to form a predetermined second angle with the first mirror in order to allow the pulse laser to advance to a measurement target

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

a light receiving lens configured to receive, from a bottom surface of the first mirror, a light reflected through the first mirror

Methodology Applied
Scientific EffectLens focusing: Lens

Implementation Method 4

a light detection part configured to convert a light signal received from the light receiving lens to an electric signal

Methodology Applied
Scientific EffectPhotoelectric conversion: Photoelectric Effect

Implementation Method 5

a motor to rotate the first mirror

Methodology Applied
Scientific EffectMechanical rotation:

Data Source

PatentEP3290986B1Multi-channel lidar scanner optical system using mirror rotation manner
Publication Date: 2021.12.15 KOREA ELECTRONICS TECH INST
  • EP3290986B1 patent drawingFigure 1~2a
  • EP3290986B1 patent drawingFigure 2b~2c
  • EP3290986B1 patent drawingFigure 3~4

AI summary

A light detection and ranging (LiDAR) optical system, according to one embodiment of the present invention, comprises: a first mirror which is disposed to make a predetermined first angle with a horizontal plane and has a first hollow; a light source for outputting a pulse laser from the lower portion of the first mirror; a second mirror which is disposed to make a predetermined second angle with the first mirror so that the pulse laser passes through the first hollow and travels to a measurement target; at least two path control mirrors which reflect the pulse laser so that the path of the pulse laser is formed on a reflective surface of the second mirror; a light receiving lens for receiving, from the lower portion of the first mirror, light which has been reflected through the first mirror; a light detecting part for converting a light signal received from the light receiving lens into an electrical signal; and a motor which is disposed between the light receiving lens and the first mirror, and rotates the first mirror.