Lidar Beam Splitter for Multi-Mode Vehicle Imaging

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Solution Overview

Problem

Current lidar imaging systems for motor vehicles are limited in their ability to efficiently utilize all available light information, leading to suboptimal performance under adverse weather conditions and a lack of additional imaging modes without degrading the lidar branch performance.

Innovation Solution

Incorporating a beam splitter in the light path to direct a portion of the light beam to a further photo detector, enabling additional imaging modes such as color, multi-spectral, and polarimetric imaging without affecting the lidar detector's performance, and using an electronic processing unit to fuse data from both detectors for enhanced image fusion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a beam splitter is added to direct light to a further photo detector, then additional imaging modes are enabled, but device complexity increases

Engineering Contradiction:
Improveimaging modesVSAvoidoptical path complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The beam splitter enables the optical system to perform multiple functions simultaneously: lidar detection and additional imaging modes (color, multi-spectral, polarimetric) share the same optical path and light source, making the system universal and multi-functional without requiring separate imaging systems

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

2Loss of information

If light is split to the further photo detector, then additional image information is obtained, but signal-to-noise ratio may deteriorate

Engineering Contradiction:
Improveimage informationVSAvoidsignal-to-noise ratio
Core Design Contradiction:
Loss of informationVSReliability

Solution Approach 1:

The beam splitter is designed with wavelength-selective properties that direct different wavelengths to different detectors: lidar wavelengths (e.g., 1550 nm) are directed to the lidar detector while other wavelengths are directed to the further photo detector, ensuring each detector receives optimal signal quality for its specific function

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If multiple beam splitters are arranged in the optical path, then multiple sensing options are enabled, but device complexity increases further

Engineering Contradiction:
Improvesensing optionsVSAvoidoptical path complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Multiple beam splitters are used to segment the optical path into distinct channels, each dedicated to a specific sensing mode (lidar, color imaging, multi-spectral imaging, polarimetric imaging), allowing independent optimization and configuration of each sensing channel while maintaining a unified optical system

Inventive Principle:
Principle #1Segmentation

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 allows for improved signal-to-noise ratios and the ability to generate complementary depth maps under adverse conditions, enhancing the overall imaging capability of the system without degrading the lidar performance, and enabling dynamic adaptation to environmental conditions.

Implementation Method 1

the beam splitter is adapted to split off a part of the light beam from said lens objective and to direct the split-off part of said light beam to said further photo detector

Methodology Applied
Scientific EffectBeam splitting: Reflection

Implementation Method 2

the beam splitter is wavelength-selecting. In this manner, it is advantageously possible to direct radiation having the laser wavelength primarily to the lidar detector, and to direct radiation having other wavelengths primarily to the further photo detector

Methodology Applied
Scientific EffectWavelength-selective reflection: Dichroic Filter

Implementation Method 3

said electronic processing unit is adapted to determine the time-of-flight of a laser pulse from said emitting section to said lidar detector

Methodology Applied
Scientific EffectTime-of-flight measurement: Time of Flight

Implementation Method 4

an emitting section adapted to emit a pulsed light beam

Methodology Applied
Scientific EffectLight emission: Laser

Implementation Method 5

a receiving section having a lens objective and a lidar detector, and an electronic processing unit, wherein light entering the lidar imaging apparatus through said lens objective is directed on said lidar detector

Methodology Applied
Scientific EffectLight focusing: Lens

Data Source

PatentEP3726247B1Lidar imaging apparatus for a motor vehicle
Publication Date: 2023.06.14 MAGNA ELECTRONICS SWEDEN AB
  • EP3726247B1 patent drawingFigure 1~2
  • EP3726247B1 patent drawingFigure 3

AI summary

A lidar imaging apparatus (30) for a motor vehicle comprises an emitting section (23) adapted to emit a pulsed light beam (3) and to change the direction of the light beam (3) in two dimensions perpendicularly to the light beam (3), a receiving section (24) having a lens objective (11) and a lidar detector (8), and an electronic processing unit (19). Light entering the lidar imaging apparatus (30) through said lens objective (11) is directed on said lidar detector (8). The electronic processing unit (19) is adapted to determine the time-of-flight of a laser pulse from said emitting section (23) to said lidar detector (8). The receiving section (24) comprises a beam splitter (60) arranged in the light path from said lens objective (11) to said lidar detector (8), and a further photo detector (61). The beam splitter (60) is adapted to split off a part of the light beam from said lens objective (11) and to direct the split-off part of said light beam to said further photo detector (61).