Light Emitting Element with Continuous Contact Interface

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Solution Overview

Problem

Existing light emitting elements, such as those using white LEDs or laser diodes, face issues with reduced fluorescence output due to light diffusion and thermal expansion leading to cracks, particularly when using powdery phosphors and air layers in the contact region between the light emitting and transmitting members.

Innovation Solution

A light emitting element with a continuous contact portion between a light emitting member formed of oxide materials and a light transmitting member of plano-convex shape, where the materials are the same and three-dimensionally entwined, preventing refraction and efficiently conducting heat to prevent cracking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a powdery phosphor and air layer are used in the contact region between light emitting member and light transmitting member, then ease of manufacture is improved, but fluorescence output decreases due to light refraction and thermal expansion causes cracking

Engineering Contradiction:

Improveease of manufactureVSAvoidreliability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

A binder material is introduced as an intermediary substance between the powdery phosphor particles and the light transmitting member. This binder fills the air layers and creates a continuous contact interface, eliminating refraction problems while maintaining ease of manufacture with powdery phosphors. The binder acts as a mediator that transmits light efficiently and accommodates thermal expansion.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The refractive index parameter of the contact region is changed from air (low refractive index) to binder material (refractive index matching phosphor and light transmitting member). This parameter change eliminates light refraction at interfaces, maintaining high fluorescence output while allowing the use of powdery phosphor structures.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If a plano-convex light transmitting member is used to control light emission, then light control capability is improved, but thermal expansion causes cracking at the contact portion

Engineering Contradiction:

Improvelight control capabilityVSAvoidstrength

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The binder material is specifically selected to have thermal expansion characteristics that match both the phosphor particles and the light transmitting member. This thermal expansion matching prevents differential expansion stresses during temperature changes, eliminating cracking while preserving the plano-convex light control structure.

Inventive Principle:

Principle #37Thermal expansion

Solution Approach 2:

The contact region is formed as a composite material structure combining binder material with phosphor particles. This composite structure provides both mechanical strength to prevent cracking and optical properties for light transmission, allowing the plano-convex shape to maintain its light control function without failure.

Inventive Principle:

Principle #40Composite materials

3Device complexity

If air layer is present in the contact region, then manufacturing simplicity is improved, but light refraction reduces fluorescence output

Engineering Contradiction:

Improvedevice complexityVSAvoidfluorescence output

Core Design Contradiction:

Device complexityVSIllumination intensity

Solution Approach 1:

The refractive index parameter of the contact medium is changed from air to binder material with refractive index matching the phosphor and light transmitting member. This single parameter change eliminates light refraction at interfaces, maintaining high fluorescence output without increasing device complexity.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The binder material creates a homogeneous contact region where the refractive index is matched across all interfaces (phosphor-binder and binder-light transmitting member). This homogeneity eliminates refraction losses while maintaining structural simplicity and ease of manufacture.

Inventive Principle:

Principle #33Homogeneity

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 configuration maintains high fluorescence output and prevents cracking, ensuring efficient light transmission and thermal management, thereby enhancing the reliability and performance of the light emitting element.

Implementation Method 1

a light transmitting member that collimates a light emitted from the light emitting member

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 2

a contact portion between the light transmitting member and the light emitting member is continuous

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

a phosphor emitting fluorescence by absorbing the light from the excitation light source

Methodology Applied

Scientific EffectFluorescence: Fluorescence

Data Source

PatentUS10290779B2Light emitting element

Publication Date: 2019.05.14 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

A light emitting element includes a light emitting member that is formed of at least two kinds of an oxide material and has a plate shape; and a light transmitting member that collimates a light emitted from the light emitting member and has a plano-convex shape, in which a contact portion between the light transmitting member and the light emitting member is continuous.