Centrifugal Precipitation for Phosphor Layer Uniformity

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Solution Overview

Problem

Light emitting devices with multiple phosphor layers exhibit variations in emission color due to inconsistent distribution of phosphor particles, leading to inconsistent performance across manufactured units.

Innovation Solution

A method of manufacturing light emitting devices that involves centrifugal precipitation of phosphor particles and fillers within resin layers to achieve consistent distribution, reducing variations in phosphor layer formation and enhancing emission color uniformity. This method includes specific steps for preparing base bodies, disposing and curing resins with phosphor particles and fillers, and optimizing centrifugal precipitation conditions to maintain desired distribution states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If multiple phosphor layers are used to reduce non-uniform color distribution, then color uniformity is improved, but variations in phosphor particle distribution occur among devices leading to emission color variations

Engineering Contradiction:
Improvecolor uniformityVSAvoidphosphor particle distribution consistency
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by performing centrifugal precipitation on the phosphor particles before the resin is fully cured. This preliminary separation action ensures uniform distribution of phosphor particles throughout the resin matrix while the resin is still in a workable state, preventing aggregation and ensuring consistent emission color across manufactured devices.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent utilizes parameter changes by controlling the viscosity of the resin and the centrifugal force applied during precipitation. By adjusting these parameters, the phosphor particles are effectively separated and uniformly distributed within the resin matrix, achieving consistent phosphor layer formation across multiple devices.

Inventive Principle:
Principle #35Parameter changes

2Illumination intensity

If phosphor particles are dispersed in resin layers, then emission color can be controlled, but variations in distribution state lead to performance variations

Engineering Contradiction:
Improveemission color controlVSAvoidperformance consistency
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The centrifugal precipitation is performed as a preliminary action before final curing, ensuring that phosphor particles are uniformly distributed in the resin matrix. This preliminary separation prevents aggregation and ensures reliable, consistent performance across all manufactured devices.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

By controlling resin viscosity and centrifugal force parameters, the patent achieves reliable and consistent phosphor particle distribution. These parameter controls ensure that emission color and performance are reliable and consistent across all manufactured devices.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If centrifugal precipitation is applied to phosphor particles in resin, then distribution uniformity is improved, but process complexity increases

Engineering Contradiction:
Improvephosphor distribution uniformityVSAvoidmanufacturing process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent changes the physical state parameter of the resin (maintaining it in a uncured or partially cured state with appropriate viscosity) to enable effective centrifugal precipitation. This parameter adjustment allows phosphor particles to be uniformly distributed without requiring overly complex manufacturing equipment or processes.

Inventive Principle:
Principle #35Parameter changes

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 method effectively reduces variations in phosphor particle distribution across light emitting devices, resulting in products with consistent emission colors and improved reliability by ensuring uniform phosphor layer formation and resistance to thermal shock.

Implementation Method 1

A method of manufacturing a light emitting device involves centrifugal precipitation of phosphor particles and fillers within resin layers to achieve consistent distribution

Methodology Applied
Scientific EffectCentrifugal precipitation: Centrifugal Separation

Implementation Method 2

disposing and curing resins with phosphor particles and fillers

Methodology Applied
Scientific EffectCuring: Phase Change

Data Source

PatentEP3617291B1Method of manufacturing light emitting device
Publication Date: 2022.06.22 NICHIA CORP
  • EP3617291B1 patent drawingFigure 1~2
  • EP3617291B1 patent drawingFigure 3~4
  • EP3617291B1 patent drawingFigure 5~6

AI summary

Provided is a method of manufacturing a light emitting device, comprising: preparing a base body having a concave portion; disposing a light emitting element at the bottom of the concave portion; disposing a first resin containing first phosphor particles having an average particle size of 10 µm or more and 30 µm or less and a first filler having an average particle size of 5 µm or more and 20 µm or less to cover the light emitting element; centrifugally precipitating the first phosphor particles and the first filler toward the base body; temporarily curing the first resin; disposing a second resin containing second phosphor particles and a second filler having an average particle size of 5 nm or more and 100 nm or less on the first resin temporarily cured; centrifugally precipitating the second phosphor particles and the second filler toward the first resin; and curing the first and second resins.