Lidar Optical Axis Adjustment via Rotated Parallel Plates

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional optical axis adjustment mechanisms for lidar apparatuses fail to provide stability and reproducibility in adjusting the position of the optical axis without changing the angle, leading to inaccuracies and difficulties in returning the optical axis to its original position, especially in outdoor environments with restrictions.

Innovation Solution

An optical axis adjustment mechanism comprising an angle adjustment mechanism, a position adjustment mechanism, and an optical axis alignment unit, where the position adjustment mechanism includes inclined parallel plates that can be rotated to independently adjust the position of the optical axis without affecting the angle, using a position detecting unit to correct deviations and ensure stability and reproducibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a conventional angle adjustment mechanism using mirrors or wedge plates is used, then the angle of the optical axis can be adjusted, but the position of the optical axis cannot be adjusted independently and becomes deviated

Engineering Contradiction:
Improveindependent adjustment capabilityVSAvoidoptical axis alignment accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The adjustment mechanism is divided into two independent segments: an angle adjustment mechanism using mirrors for angular adjustment, and a position adjustment mechanism using parallel plates for positional adjustment. This segmentation allows independent control of angle and position without mutual interference, resolving the contradiction between ease of operation and measurement precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Parallel plates are introduced as an intermediary component between the angle adjustment mechanism and the optical axis alignment unit. These parallel plates specifically handle position adjustment without affecting the angle, acting as a mediator that decouples the two adjustment functions and enables independent position control.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If mirrors are used for angle adjustment, then the angle can be adjusted, but returning the optical axis to its original position becomes difficult when great angle deviation occurs

Engineering Contradiction:
Improveadjustment rangeVSAvoidreset capability
Core Design Contradiction:
Adaptability or versatilityVSEase of repair

Solution Approach 1:

By segmenting the adjustment functions into angle adjustment (mirrors) and position adjustment (parallel plates), the system can independently reset the position component without affecting the angle settings. This allows easy return to the original position even after large angle deviations, as the parallel plates can compensate for positional shifts caused by angle adjustments.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The position adjustment mechanism using parallel plates can be reset to its initial state independently of the angle adjustment mechanism. This discarding of the position deviation and recovering of the original position is achieved by rotating the parallel plates back to their initial orientation, while maintaining the angle adjustments made by the mirrors.

Inventive Principle:
Principle #34Discarding and recovering

3Ease of operation

If two mirrors are used for simultaneous angle and position adjustment, then adjustment is possible, but angle deviation and position deviation occur when either mirror deviates

Engineering Contradiction:
Improvesimultaneous adjustment capabilityVSAvoidadjustment stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The adjustment system is segmented into two independent mechanisms: mirrors for angle adjustment and parallel plates for position adjustment. This eliminates the coupling effect where mirror deviation causes both angle and position errors. Each mechanism independently controls its specific parameter, improving reliability by preventing error propagation between angle and position adjustments.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The position adjustment function is extracted from the mirror-based angle adjustment mechanism and implemented separately using parallel plates. This extraction removes the harmful coupling effect where mirror position changes inadvertently alter the optical axis position, thereby improving adjustment stability and reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

4Ease of operation

If parallel plates are rotated about an axis perpendicular to the reference optical axis, then position adjustment is possible, but stability and reproducibility of the adjustment are low

Engineering Contradiction:
Improveposition adjustment capabilityVSAvoidadjustment stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

Instead of rotating the parallel plates about an axis perpendicular to the reference optical axis, the invention inverts the approach by rotating them about an axis parallel to the reference optical axis. This inversion of the rotation axis provides better stability and reproducibility because the rotation occurs around a more stable reference that coincides with the optical path, reducing mechanical play and improving adjustment repeatability.

Inventive Principle:
Principle #13The other way round (Inversion)

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 mechanism achieves stable and reproducible optical axis adjustments by allowing independent positioning of the optical axis without altering the angle, ensuring accurate alignment and easy return to the original position, even in restricted outdoor environments.

Implementation Method 1

a first parallel plate arranged on the reference optical axis with a normal to an incidence surface thereof being inclined with respect to the reference optical axis; a first rotating mechanism for rotating the first parallel plate about the reference optical axis; a second parallel plate arranged on the reference optical axis with a normal to an incidence surface thereof being inclined with respect to the reference optical axis; and a second rotating mechanism for rotating the second parallel plate about the reference optical axis

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP3462209B1Optical axis adjustment mechanism and lidar device
Publication Date: 2020.09.23 MITSUBISHI ELECTRIC CORP
  • EP3462209B1 patent drawingFigure 1~2
  • EP3462209B1 patent drawingFigure 3A~3B
  • EP3462209B1 patent drawingFigure 4A~4C

AI summary

An angle adjustment mechanism (1) arranged on a reference optical axis (102) for laser light (101), for adjusting the angle of an optical axis of the incident laser light (101), and a position adjustment mechanism (2) arranged on the reference optical axis (102), for adjusting the position of the optical axis of the incident laser light (101) are included, and the position adjustment mechanism (2) has a first parallel plate (21) arranged on the reference optical axis (102) with the normal to an incidence surface thereof being inclined against the reference optical axis (102), a first rotating mechanism (22) for rotating the first parallel plate (21) about the reference optical axis (102), a second parallel plate (23) arranged on the reference optical axis (102) with the normal to an incidence surface thereof being inclined against the reference optical axis (102), and a second rotating mechanism (24) for rotating the second parallel plate (23) about the reference optical axis (102).