Ultrasonic Sensor for Phosphor Monitoring in Laser Headlights

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Solution Overview

Problem

Current motor vehicle headlight monitoring systems for phosphor function are expensive and time-consuming due to the need for multiple sensors to detect deviations in laser light conversion, which can lead to undesired or dangerous situations if the phosphor ages or is damaged.

Innovation Solution

A single ultrasonic sensor element with a transmitter and receiver is acoustically coupled to the phosphor, using ultrasound to detect even minor deviations in the phosphor's function, allowing for reliable monitoring and reducing the need for multiple sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple sensors are used to monitor phosphor function, then measurement precision and reliability are improved, but device complexity and cost increase

Engineering Contradiction:
Improvephosphor function detection accuracyVSAvoidnumber of sensors
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The ultrasonic sensor element is designed to perform multiple functions: it generates ultrasonic waves, detects reflected ultrasonic waves, and monitors phosphor function through acoustic coupling. This single multi-functional component replaces what would traditionally require multiple specialized sensors, thereby reducing device complexity while maintaining monitoring capability

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

Solution Approach 2:

The patent replaces optical/electronic sensing mechanisms with an ultrasonic mechanical sensing approach. By using ultrasonic waves that propagate through the phosphor material and detecting changes in acoustic properties, the system achieves phosphor function monitoring through a fundamentally different physical mechanism that can be implemented with a single sensor element

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

2Reliability

If multiple sensors are deployed to detect all error scenarios, then reliability is improved, but ease of operation and maintenance deteriorate

Engineering Contradiction:
Improvemonitoring system reliabilityVSAvoidsystem simplicity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The ultrasonic sensor element is directly acoustically coupled to the phosphor, allowing it to autonomously detect phosphor degradation and functional changes without requiring external complex measurement systems. The sensor essentially monitors itself and the phosphor together as an integrated system, simplifying operation and maintenance

Inventive Principle:
Principle #25Self-service

3Measurement precision

If conventional optical sensors are used to monitor conversion light, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improveconversion light detection accuracyVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent substitutes optical detection mechanisms with ultrasonic acoustic detection. Instead of measuring optical properties of conversion light, the system uses ultrasonic waves to probe the phosphor material's physical state, which indirectly but reliably indicates conversion function. This mechanical/acoustic approach simplifies the sensor system while maintaining measurement precision

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

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 enables simple and reliable monitoring of the conversion device or phosphor, ensuring safe operation by detecting functional deviations with a single sensor element, thereby preventing unintended laser light release.

Implementation Method 1

The sensor element comprises an ultrasonic unit with an ultrasonic transmitter and receiver. The ultrasound unit is preferably acoustically coupled to the phosphor.

Methodology Applied
Scientific EffectUltrasound: Ultrasound

Implementation Method 2

converting the received light into conversion light using at least one phosphor of the conversion device

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Implementation Method 3

detecting an intended function of the conversion device using a sensor element

Methodology Applied
Scientific EffectAcoustic detection: Acoustic Emission

Data Source

PatentEP3204261B1Monitoring an illumination device comprising a conversion device and laser-based illuminating means
Publication Date: 2019.11.20 AUDI AG
  • EP3204261B1 patent drawingFigure 1~2
  • EP3204261B1 patent drawingFigure 3~4
  • EP3204261B1 patent drawingFigure 5~6

AI summary

The invention relates to a conversion device for a motor vehicle headlight comprising a luminescent material (18) for converting captured light (16) into conversion light (20) and a sensor element (22) for monitoring the luminescent material (18), characterized in that the sensor element (22) comprises an ultrasonic unit (30) comprising an ultrasonic transmitter and receiver.