Laser Scanner Deflection Mirror Beam Distortion

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Solution Overview

Problem

Conventional laser scanners with multiple measurement channels face challenges in directing transmitted light beams onto a micromirror with minimal distortion, particularly due to the use of convex lenses which require a large aperture and short focal length, leading to physical limitations and beam distortion.

Innovation Solution

The use of a deflection mirror system that reflects transmitted light beams onto a micromirror without loss or distortion, allowing for a large degree of freedom in the geometric arrangement of optical transmitters and deflection devices, with each optical transmitter potentially having a dedicated deflection mirror to achieve the desired angular spacing and scanning plane configuration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a convex lens is used to direct transmitted light beams onto the micromirror, then the light beams can be focused, but beam distortion occurs and physical limitations are reached

Engineering Contradiction:
Improvebeam direction precisionVSAvoidbeam distortion
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

A flat deflection mirror is introduced as an intermediary component between the optical transmitter and the micromirror. This deflection mirror redirects the transmitted light beams onto the micromirror without introducing distortion, while the original convex lens can be used unchanged for focusing, thus separating the beam direction function from the beam quality preservation function

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the conventional lens-based beam direction system with a mirror-based deflection system. Instead of using a convex lens to both focus and direct beams (which causes distortion), the system uses a flat deflection mirror to redirect beams and a separate convex lens to focus them, substituting the mechanical/optical path with a reflection-based approach that preserves beam quality

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

2Adaptability or versatility

If a convex lens with large aperture and short focal length is used, then the angular distance between transmitted light beams can be increased, but physical limits are reached

Engineering Contradiction:
Improveangular spacing flexibilityVSAvoidlens design constraints
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the optical system into separate functional components: a deflection mirror for beam direction and convex lenses for focusing. This segmentation allows independent optimization of each component, enabling larger angular distances between beams without requiring extreme lens parameters, thus reducing device complexity while maintaining adaptability

Inventive Principle:
Principle #1Segmentation

3Productivity

If multiple optical transmitters are used for high scanning speed, then scanning efficiency is improved, but directing all beams onto the micromirror becomes more complex

Engineering Contradiction:
Improvescanning speedVSAvoidbeam path arrangement
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements a universal deflection mirror arrangement where each optical transmitter has its own deflection mirror. This allows multiple transmitters to operate independently and simultaneously direct their beams onto the micromirror, maintaining high scanning speed while simplifying the overall beam path arrangement through a standardized, scalable configuration

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 minimizes beam distortion and allows for a larger angular distance between transmitted light beams, enhancing scanning efficiency and accuracy while maintaining high precision and speed, enabling effective scanning processes with elevation capabilities.

Implementation Method 1

The deflection mirror reflects the transmitted light beam without loss or distortion

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

a micromirror that can be pivoted about at least one axis, preferably two axes that are perpendicular to one another

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

Light pulses are emitted and reflected on any object that may be present, with the time until the reflected signal is received being proportional to the distance

Methodology Applied
Scientific EffectLight propagation: Light

Data Source

PatentEP3347732B1Laser scanner for motor vehicles
Publication Date: 2021.01.13 VALEO SCHALTER & SENSOREN GMBH
  • EP3347732B1 patent drawingFigure 1
  • EP3347732B1 patent drawingFigure 2
  • EP3347732B1 patent drawingFigure 3~4

AI summary

The invention relates to a laser scanner (1') for motor vehicles, having at least two optical transmitters (12, 13, 14) each for emitting a transmission light beam (3, 4, 5), a micromirror (6) which is arranged in a rotatable manner and is intended to deflect the transmission light beams (3, 4, 5) onto the scene to be measured. The laser scanner also comprises an optical deflection device which is arranged in front of the micromirror (6) in the beam path of at least one transmission light beam (3, 4, 5) and is designed and arranged in such a manner that the transmission light beams (3, 4, 5) are directed onto the micromirror (6). In order to align a plurality of transmission light beams with the micromirror in a laser scanner with as little distortion as possible, the invention provides for the deflection device (20) to have at least one deflection mirror (21, 22) arranged in the beam path of a transmission light beam (3, 4, 5).