Phosphor Particle Precipitation in LED Sealing Resin

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Solution Overview

Problem

The existing method of decreasing the viscosity of sealing resin to precipitate phosphor particles in light-emitting devices can result in uneven precipitation, leading to inconsistencies in emission color due to varying degrees of precipitation among different types of phosphor particles.

Innovation Solution

A method involving a light-emitting device manufacturing process where phosphor particles are precipitated at predetermined positions within separate sealing materials, with the second phosphor particles being precipitated before the second sealing material cures, ensuring even distribution and reducing color unevenness, and optionally using a dispersant to improve dispersibility and refractive index control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the viscosity of sealing resin is decreased by heating to precipitate phosphor particles, then phosphor particles can be precipitated in the sealing resin, but uneven precipitation occurs among different types of phosphor particles resulting in unevenness in emission color

Engineering Contradiction:

Improveuniformity of phosphor particle distributionVSAvoidemission color uniformity

Core Design Contradiction:

Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The patent divides the sealing resin into multiple layers, with each layer containing a specific type of phosphor particle. By segmenting the sealing resin structure, different phosphor particles are confined to their respective layers, preventing uneven precipitation and ensuring uniform emission color across the light-emitting device.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different properties to different parts of the sealing resin by creating layered structures where each layer has specific phosphor particles dispersed uniformly. This local quality approach ensures that each region of the sealing resin has the desired phosphor composition, preventing color unevenness.

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If multiple types of phosphor particles are placed in different layers of sealing resin, then emission color can be controlled, but the manufacturing process becomes more complex

Engineering Contradiction:

Improveemission color controlVSAvoidmanufacturing process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent uses segmentation to create separate layers for different phosphor types, which simplifies the manufacturing process by allowing each layer to be prepared and applied independently. This modular approach makes it easier to control emission colors while managing manufacturing complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent creates a multi-functional sealing resin structure that simultaneously serves as the sealing medium and the phosphor carrier. This universal approach combines multiple functions into a single integrated structure, reducing overall device complexity while maintaining precise emission color control.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 allows for the production of light-emitting devices with reduced color unevenness by ensuring precise positioning of phosphor particles, enhancing light extraction efficiency and maintaining desired emission colors.

Implementation Method 1

a method of manufacturing a light-emitting device comprises: providing a case comprising a recessed portion and mounting a light-emitting element on a bottom of the recessed portion; putting a first sealing material comprising a first phosphor particle into the recessed portion; putting a second sealing material comprising a second phosphor particle on the first sealing material in the recessed portion; and precipitating the second phosphor particle before the second sealing material cures

Methodology Applied

Scientific EffectViscosity decrease through heating: Heating

Implementation Method 2

the first phosphor particle has a longer fluorescence wavelength than the second phosphor particle

Methodology Applied

Scientific EffectFluorescence: Fluorescence

Data Source

PatentUS10461225B2Method of manufacturing light-emitting device including sealing materials with phosphor particles

Publication Date: 2019.10.29 TOYODA GOSEI CO LTD

AI summary

A method of manufacturing a light-emitting device includes providing a case including a recessed portion and mounting a light-emitting element on a bottom of the recessed portion, putting a first sealing material including a first phosphor particle into the recessed portion, putting a second sealing material including a second phosphor particle on the first sealing material in the recessed portion, and precipitating the second phosphor particle before the second sealing material cures. The second phosphor particle is located above the first phosphor particle after the first and second sealing materials cure.