Phosphor Embedding in Softened Glass Matrix

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Solution Overview

Problem

Conventional conversion elements with silicone as the matrix material suffer from poor heat dissipation, leading to thermal stress and efficiency loss of phosphors, while using glass as a matrix material requires high temperatures that can damage the phosphors during the sintering process.

Innovation Solution

A method where phosphors are introduced into a glass material in a compact or softened form, avoiding initial mixing with the matrix and subsequent heat treatment, allowing the phosphors to sink into the glass at lower temperatures, thus minimizing thermal stress and damage, and utilizing glass as a superior heat conductor for improved efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If glass is used as matrix material, then heat dissipation is improved, but phosphor damage occurs due to high temperature requirements

Engineering Contradiction:
Improveheat dissipationVSAvoidphosphor damage
Core Design Contradiction:
Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The glass matrix is pre-formed into a compact or softened form before phosphor incorporation. This preliminary preparation allows the glass to be ready for phosphor embedding without requiring high-temperature sintering that would damage the phosphor, thus achieving both good heat dissipation and phosphor protection.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The glass material is heated to a softened state (but not to full melting temperature) to enable phosphor incorporation. This parameter change allows the glass to become sufficiently pliable for phosphor embedding while avoiding the high temperatures that would damage the phosphor, resolving the contradiction between heat dissipation requirements and phosphor protection.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If phosphor is mixed with glass material at the beginning, then manufacturing is simplified, but high temperature heat treatment damages the phosphor

Engineering Contradiction:
Improvemanufacturing processVSAvoidphosphor damage
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The manufacturing process is segmented into distinct stages: first forming the glass matrix in compact or softened form, then separately incorporating the phosphor. This segmentation avoids the need to mix phosphor with glass powder from the beginning, eliminating exposure to high-temperature sintering while still achieving good manufacturing feasibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The glass matrix is prepared in advance in a compact or softened form before phosphor incorporation. This preliminary action separates the glass formation step from phosphor incorporation, allowing the phosphor to be added after the glass structure is already established, thus avoiding high-temperature damage.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If phosphor is incorporated into silicone, then manufacturing is easy, but heat dissipation is poor leading to efficiency loss

Engineering Contradiction:
Improvemanufacturing processVSAvoidheat dissipation
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The matrix material is changed from silicone to glass, fundamentally altering the thermal conductivity parameter. Glass provides superior heat dissipation capabilities compared to silicone, resolving the heat dissipation issue while the described incorporation method maintains manufacturing feasibility.

Inventive Principle:
Principle #35Parameter changes

4Manufacturing precision

If high temperature sintering is used to embed phosphor in glass, then phosphor incorporation is achieved, but manufacturing complexity and phosphor damage increase

Engineering Contradiction:
Improvephosphor embeddingVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The glass is heated to a softened state (below full melting temperature) to enable phosphor embedding. This parameter optimization achieves sufficient pliability for phosphor incorporation while avoiding the high temperatures and prolonged processing of full sintering, thus reducing manufacturing complexity and phosphor damage risk.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The glass matrix is pre-formed into a compact or softened form before phosphor incorporation. This preliminary preparation eliminates the need for high-temperature sintering to form the glass structure itself, simplifying the overall process while achieving effective phosphor embedding.

Inventive Principle:
Principle #10Preliminary action

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 enhances heat dissipation and reduces the risk of phosphor damage, enabling the use of glass as a matrix material without compromising the optical properties of the conversion element, resulting in a more efficient and durable conversion element.

Implementation Method 1

Glass as a matrix material has the advantage of better thermal conductivity, which is on average ten times higher than that of silicone. This means the phosphors heat up less during operation and are therefore more efficient.

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

The phosphor is subsequently embedded into the softened glass material by sinking it in at an elevated temperature.

Methodology Applied
Scientific EffectThermal softening: Heat Treatment

Data Source

PatentEP2729426B1Method for producing a conversion element, and conversion element
Publication Date: 2020.04.08 OSRAM GMBH
  • EP2729426B1 patent drawingFigure 1A~1B
  • EP2729426B1 patent drawingFigure 1C~1D
  • EP2729426B1 patent drawingFigure 2A~2B

AI summary

The invention relates to a method for producing a conversion element (10) for an optical and/or optoelectronic component, wherein the method comprises at least the following steps: a) applying a luminescent substance (4; 4a) or a material (3a) that contains a luminescent substance (4; 4a) to a surface of a transparent and homogeneous glass material (2a) that is free of luminescent substance and performing a temperature treatment (TB1) at an elevated temperature (T1) above the softening temperature of the glass material (2a), whereby the glass material (2a) is softened to such an extent that the luminescent substance (4; 4a) sinks into the glass material (2a); and b) cooling the glass material (2a) along with the luminescent substance (4; 4a) that has sunk in.