Dual-Laser Fluorescent Light Source for Stable Chromaticity

Solution Overview

Problem

Light emitting devices with semiconductor lasers and fluorescent materials experience shifts in chromaticity due to temperature changes, leading to inconsistent light output in applications requiring stable color across varying temperatures.

Innovation Solution

A light emitting device configuration using multiple laser elements with peak wavelengths on both sides of the fluorescent material's excitation peak, which reduces the impact of temperature-induced wavelength shifts, ensuring consistent chromaticity by adjusting the intensity of fluorescent light emission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single laser element is used to excite fluorescent material, then the device structure is simple, but chromaticity shifts significantly with temperature changes

Engineering Contradiction:

Improvedevice structureVSAvoidchromaticity stability

Core Design Contradiction:

Device complexityVSStability of the object's composition

Solution Approach 1:

The patent divides the laser excitation source into multiple laser elements with different peak wavelengths. Specifically, it uses a first laser element with peak wavelength shorter than the fluorescent material's excitation peak, and a second laser element with peak wavelength longer than the excitation peak. This segmentation allows the system to compensate for temperature-induced wavelength shifts by adjusting the relative intensities of the two laser elements, thereby maintaining stable chromaticity output.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the wavelength parameter of the laser excitation source by using multiple laser elements with different peak wavelengths. By selecting laser elements whose peak wavelengths are positioned on both sides of the fluorescent material's excitation peak, the system can adjust the excitation intensity distribution to compensate for temperature variations, thus maintaining stable chromaticity characteristics.

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If multiple laser elements with different peak wavelengths are used, then chromaticity stability is improved, but device complexity increases

Engineering Contradiction:

Improvechromaticity stabilityVSAvoiddevice structure

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent divides the laser excitation source into multiple laser elements with different peak wavelengths. Specifically, it uses a first laser element with peak wavelength shorter than the fluorescent material's excitation peak, and a second laser element with peak wavelength longer than the excitation peak. This segmentation allows the system to compensate for temperature-induced wavelength shifts by adjusting the relative intensities of the two laser elements, thereby maintaining stable chromaticity output.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent converts the harmful effect of temperature-induced wavelength drift into a beneficial compensation mechanism. By positioning laser elements on both sides of the excitation peak, the system可以利用 the wavelength shifts caused by temperature changes to maintain optimal excitation conditions through intensity adjustment, thus turning the harmful thermal drift into a useful compensation effect.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 solution effectively minimizes chromaticity shifts due to temperature changes, maintaining consistent light color across a wide temperature range, particularly beneficial for in-vehicle applications.

Implementation Method 1

a fluorescent material having an excitation spectrum with an excitation peak

Methodology Applied

Scientific EffectFluorescence: Fluorescence

Data Source

PatentEP3331108B1Light emitting device and method of producing the light emitting device

Publication Date: 2024.05.15 NICHIA CORP

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AI summary

A light emitting device 10 includes a fluorescent material 13, a first laser element 11 and a second laser element 12. The first laser element 11 is configured to emit a first laser light to excite the fluorescent material 13. The first laser light having a first peak wavelength that is shorter than an excitation peak wavelength of the fluorescent material 13. The second laser element 12 is configured to emit a second laser light to excite the fluorescent material 13. The second laser light has a second peak wavelength that is longer than the excitation peak wavelength of the fluorescent material 13.