Luminescence Conversion Element Spacing and Reflector Design

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Solution Overview

Problem

Semiconductor light sources with primary radiation sources and luminescence conversion elements face inefficiencies due to high temperature increases in the luminescence conversion element, leading to reduced wavelength conversion efficiency, especially at high energy densities.

Innovation Solution

A semiconductor light source design featuring a luminescence conversion module spaced from the primary radiation source and connected to a heat sink for effective heat dissipation, combined with a reflector layer for enhanced radiation conversion and a thermally conductive connection, utilizing inorganic phosphors and ceramic materials for improved thermal conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the luminescence conversion element is irradiated with high energy density from the primary radiation source, then the luminance output is improved, but the temperature increase of the luminescence conversion element increases, reducing wavelength conversion efficiency

Engineering Contradiction:
Improveluminance outputVSAvoidtemperature increase of luminescence conversion element
Core Design Contradiction:
Illumination intensityVSTemperature

Solution Approach 1:

The patent introduces a temporal dimension to the heat dissipation process by using pulsed irradiation. The primary radiation source operates in pulses, creating time-separated irradiation and cooling phases. This allows the luminescence conversion element to dissipate heat between pulses, maintaining lower operating temperatures even at high energy densities, thereby preserving wavelength conversion efficiency while achieving high luminance output during active pulses

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The system employs periodic pulsed irradiation where the primary radiation source is activated in repeated cycles. During each pulse, high energy density is delivered to generate luminance. Between pulses, the luminescence conversion element cools down through its thermal connection to the heat sink. This periodic operation enables sustained high-performance output without continuous temperature buildup that would degrade conversion efficiency

Inventive Principle:
Principle #19Periodic action

2Use of energy by moving object

If the luminescence conversion element is positioned close to the primary radiation source, then the coupling of primary radiation is improved, but the heat dissipation from the luminescence conversion element is impaired

Engineering Contradiction:
Improvecoupling of primary radiationVSAvoidheat dissipation from luminescence conversion element
Core Design Contradiction:
Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The patent introduces an optical intermediary structure (such as a light guide or optical coupling element) that mediates between the primary radiation source and the luminescence conversion element. This intermediary enables effective radiation coupling over larger distances by guiding and distributing the primary radiation across the luminescence conversion element surface, while simultaneously allowing the luminescence conversion element to be positioned away from the heat source for improved heat dissipation through its thermal connection to the heat sink

Inventive Principle:
Principle #24Intermediary (Mediator)

3Loss of energy

If a heat sink is added to the luminescence conversion module, then the heat dissipation is improved, but the device complexity increases

Engineering Contradiction:
Improveheat dissipationVSAvoiddevice complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent merges the heat sink function with the structural support function by integrating the heat sink directly into the mounting substrate or housing structure that already supports the luminescence conversion module. This consolidation eliminates the need for separate heat dissipation components, reducing device complexity while maintaining effective heat dissipation through the thermally conductive connection to the luminescence conversion element

Inventive Principle:
Principle #5Merging (Combining)

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 design achieves high efficiency in wavelength conversion and luminance with reduced phosphor temperature increases, allowing for efficient heat dissipation and a compact, high-luminance semiconductor light source.

Implementation Method 1

the luminescence conversion element absorbs primary radiation and is thereby excited - for example, by means of fluorescence or phosphorescence - to emit secondary radiation

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Implementation Method 2

the luminescence conversion element absorbs primary radiation and is thereby excited - for example, by means of fluorescence or phosphorescence - to emit secondary radiation

Methodology Applied
Scientific EffectPhosphorescence: Phosphorescence

Implementation Method 3

the luminescence conversion element is thermally connected to the heat sink

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2198465B1Semiconductor light source having a primary radiation source and a luminescence conversion element
Publication Date: 2019.05.15 OSRAM OPTO SEMICON GMBH & CO OHG
  • EP2198465B1 patent drawingFigure 1~2
  • EP2198465B1 patent drawingFigure 3A~3C
  • EP2198465B1 patent drawingFigure 4~5

AI summary

The invention relates to a semiconductor light source having a primary radiation source (1) that, in operation, emits electromagnetic primary radiation (5) in a first wavelength range and having a luminescence conversion module (2) into which primary radiation (5) emitted by the primary radiation source (1) is coupled. The luminescence conversion module (2) comprises a luminescence conversion element (6) that absorbs primary radiation (5) from the first wavelength range by means of a luminescent material and emits electromagnetic secondary radiation (15) in a second wavelength range. The luminescence conversion element (6) is disposed at a distance from the primary radiation source (1) on a cooling body (3). Said luminescence conversion element (6) comprises a reflector surface (7, 71, 72) that reflects back primary radiation (5) traveling into the luminescence conversion element (6) but not absorbed thereby and/or reflects secondary radiation (15) in the direction of a light decoupling surface (601) of the luminescence conversion element (6).