Vehicle Headlamp Light Scanner Laser Power Optimization

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Solution Overview

Problem

Existing headlight systems using micromirrors with resonant drive principles suffer from inefficient laser power utilization due to sinusoidal movement, leading to uneven light distribution, where edge areas receive more power than the center, necessitating power compensation that reduces overall laser power usage and performance.

Innovation Solution

The method involves subdividing the luminous image into pixels and optimizing control characteristics by determining the maximum illuminance per column or row, calculating the time unit per illuminance, and adjusting the micromirror deflection angle to achieve a new optimized control characteristic, which is used to control the micromirror, thereby improving laser power utilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If resonant drive principle with sinusoidal micromirror movement is used, then the micromirror can be driven efficiently at resonant frequency, but the laser power utilization becomes uneven with edge areas receiving more power than center

Engineering Contradiction:
Improvemicromirror oscillation frequencyVSAvoidlight distribution uniformity
Core Design Contradiction:
SpeedVSIllumination intensity

Solution Approach 1:

The patent transitions from fixed resonant frequency operation to dynamic control where the micromirror can operate in both resonant and non-resonant modes. The system dynamically adjusts the drive frequency and amplitude based on the desired light distribution pattern, allowing optimization of both speed and illumination uniformity for different operating conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the operational parameters of the micromirror by introducing variable drive frequencies and amplitudes. By adjusting these parameters dynamically, the system can compensate for the sinusoidal movement effect and achieve more uniform light distribution while maintaining efficient operation.

Inventive Principle:
Principle #35Parameter changes

2Illumination intensity

If laser power is reduced in edge areas to compensate for sinusoidal movement, then light distribution becomes more uniform, but overall laser power utilization decreases by 60%

Engineering Contradiction:
Improvelight distribution uniformityVSAvoidlaser power utilization
Core Design Contradiction:
Illumination intensityVSUse of energy by moving object

Solution Approach 1:

The system dynamically adjusts micromirror operation modes based on real-time requirements. When high power utilization is needed, it operates in non-resonant mode with optimized dwell times. When uniform distribution is prioritized, it uses resonant mode with compensation algorithms, thus avoiding the 60% power reduction penalty.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent utilizes periodic resonant oscillations but introduces variable amplitude modulation and dwell time control. By strategically extending dwell time in under-illuminated areas and reducing it in over-illuminated areas, the system achieves uniform light distribution without reducing overall laser power by 60%.

Inventive Principle:
Principle #19Periodic action

3Use of energy by moving object

If linear control is used instead of resonant drive to improve laser power utilization to 20-30%, then more laser diodes must be installed (3x increase), significantly increasing headlight cost

Engineering Contradiction:
Improvelaser power utilizationVSAvoidnumber of laser diodes
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent implements dynamic control that allows a single laser diode to achieve power utilization levels previously requiring multiple diodes. By dynamically adjusting micromirror dwell times and oscillation parameters, the system maximizes the effective use of installed laser power, reducing the need for additional laser diodes and associated costs.

Inventive Principle:
Principle #15Dynamics

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 significantly increases the utilization of installed laser power, potentially up to 100% in critical areas, reducing the need for excessive laser diode installation and enhancing the efficiency of light distribution in headlight systems.

Implementation Method 1

the laser beam of at least one modulated laser light source being scanned by the light scanner and directed onto a light conversion medium

Methodology Applied
Scientific EffectOptical reflection: Reflection

Implementation Method 2

at least one modulated laser light source, the laser beam of which can be scanned

Methodology Applied
Scientific EffectLaser emission: Laser

Implementation Method 3

The modulation of the laser light source determines the desired luminance for each point or each line of the light image

Methodology Applied
Scientific EffectLight modulation: Phase Modulation

Implementation Method 4

the laser beam of at least one modulated laser light source being scanned by the light scanner and directed onto a light conversion medium in order to generate a luminous image there

Methodology Applied
Scientific EffectFluorescence conversion: Fluorescence

Data Source

PatentEP3289282B1Method for controlling a light scanner in a headlamp for vehicles
Publication Date: 2022.01.19 ZKW GRP GMBH
  • EP3289282B1 patent drawingFigure 1
  • EP3289282B1 patent drawingFigure 2~3
  • EP3289282B1 patent drawingFigure 4~7

AI summary

A method for controlling a light scanner (7) in a headlamp for vehicles, wherein the laser beam of at least one modulated laser light source (1) is directed by means of the light scanner onto a light conversion means (8) in a scanning manner in order to generate a light image (11) on same, which is projected as a light image (11') via an imaging system (12) onto the road, a micro-mirror (10) of the light scanner is pivoted in at least one coordinate direction according to determined control characteristics, the desired light image (11) is split into a pixel quantity with n rows and/or m columns, the horizontal and/or vertical control characteristic for the micro-mirror (10) is adjusted to at least one selected row and/or column according to the required optical performance of the pixel, and the adjusted horizontal and/or vertical control characteristic is used to control the micro-mirror.