Light-Emitting Device Package With Conformable Phosphor Layer

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing light-emitting device packages face issues with phosphor layer deterioration, light leakage, and color variance in white light emission, particularly due to the thermal printing process and potential cracking of the phosphor film.

Innovation Solution

A package for a light-emitting device with a phosphor layer formed in a conformable thickness and hardness range of 25 to 75 Durometer Shore D, made from a mixture of phosphor and silicon with a hardener, and a heat-blocking layer of transparent silicon to prevent heat transfer and ensure firm attachment without thermal printing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a phosphor film is attached by a thermal printing process, then the phosphor layer can be formed on the light-emitting device, but the phosphor film is deteriorated and cracks are generated

Engineering Contradiction:

Improvephosphor layer formationVSAvoidphosphor layer integrity

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

A buffer layer is introduced as an intermediary between the light-emitting device and the phosphor layer. This buffer layer absorbs thermal stress and prevents direct heat transfer from the light-emitting device to the phosphor layer during attachment, thereby preventing crack formation while still enabling the phosphor layer to be formed on the device.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The attachment method is changed from thermal printing to a method that controls attachment temperature and stress parameters. By changing the attachment parameters (using lower temperature and controlled stress), the phosphor layer can be attached without exceeding its thermal tolerance, preventing deterioration and cracking.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the phosphor layer is formed to cover all regions, then light leakage is prevented, but manufacturing complexity increases

Engineering Contradiction:

Improvelight leakage preventionVSAvoidphosphor layer configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The phosphor layer is configured with different properties in different regions: in the light emission region, the phosphor layer has optimal thickness and composition for light conversion, while in the peripheral regions, the phosphor layer extends to prevent light leakage but with adjusted properties to maintain manufacturing feasibility. This local differentiation allows light leakage prevention without excessive complexity.

Inventive Principle:

Principle #3Local quality

3Power

If the phosphor layer thickness is increased, then light conversion efficiency is improved, but color variance in white light increases

Engineering Contradiction:

Improvelight conversion efficiencyVSAvoidcolor uniformity

Core Design Contradiction:

PowerVSManufacturing precision

Solution Approach 1:

Instead of increasing thickness to improve light conversion, the invention changes other parameters: phosphor material composition, particle size distribution, and excitation wavelength are optimized to achieve high conversion efficiency while maintaining uniform color output. This parameter substitution allows efficiency improvement without the negative effect of increased thickness on color uniformity.

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 solution effectively suppresses phosphor layer deterioration, prevents light leakage, reduces color variance, and ensures crack-free attachment of the phosphor layer, enhancing the reliability and quality of white light emission.

Implementation Method 1

a phosphor layer formed over the light-emitting device other than regions where the electrode pads are formed and configured to convert the light of the light-emitting device into white light by changing the wavelength of the light provided by the light-emitting device

Methodology Applied

Scientific EffectPhosphorescence: Phosphorescence

Implementation Method 2

a heat-blocking layer configured to suppress a transfer of heat from the light-emitting device to the phosphor layer between the light-emitting device and the phosphor layer

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentUS9130132B2Package for light-emitting device

Publication Date: 2015.09.08 LIGHTIZER KOREA

AI summary

The present invention provides a package for a light-emitting device, including the light-emitting device configured to provide light having a specific wavelength region, electrode pads formed on the light-emitting device, and a phosphor layer formed over the light-emitting device other than regions where the electrode pads are formed and configured to convert the light of the light-emitting device into white light by changing the wavelength of the light provided by the light-emitting device, wherein the phosphor layer is formed in a conformable thickness and is formed in a region wider than an upper region of the light-emitting device other than the regions where the electrode pads are formed.