Flexible LED Assemblies with Dual-Surface Phosphor for Blue Light Control

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Solution Overview

Problem

LED chips in packaged assemblies are prone to performance degradation due to exposure to humidity and chemical atmospheres, and blue light leakage can be harmful to human eyes, requiring effective sealing and heat dissipation while maintaining light extraction and color accuracy.

Innovation Solution

A flexible LED assembly with a transparent substrate, blue LED chips electrically connected to conductive sections, and wavelength conversion layers of phosphor on both surfaces to encapsulate blue light and convert it into white light, allowing for omnidirectional lighting with reduced blue light leakage and adjustable filament length and voltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If LED chips are exposed to atmosphere for light extraction, then light emission is improved, but performance degradation due to humidity and chemical exposure occurs

Engineering Contradiction:

Improvelight extractionVSAvoidperformance degradation

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The patent uses a flexible transparent substrate as a protective shell that encapsulates the LED chips while allowing light transmission. This thin film structure provides environmental protection against humidity and chemicals while maintaining light extraction efficiency, resolving the contradiction between exposure and protection.

Inventive Principle:

Principle #30Flexible shells and thin films

2Reliability

If epoxy resins are used to seal LED chips, then protection from atmosphere is improved, but heat dissipation and light extraction are hindered

Engineering Contradiction:

Improveprotection from atmosphereVSAvoidheat dissipation

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The patent employs a composite structure combining a flexible transparent substrate with conductive sections and wavelength conversion layers. This composite material system provides atmospheric protection while enabling effective heat dissipation pathways and maintaining optical performance, overcoming the limitations of traditional epoxy resin encapsulation.

Inventive Principle:

Principle #40Composite materials

3Illumination intensity

If phosphor is used to convert blue light, then color accuracy is improved, but blue light leakage is reduced

Engineering Contradiction:

Improvecolor accuracyVSAvoidblue light leakage

Core Design Contradiction:

Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent uses wavelength conversion layers containing phosphor materials as an intermediary substance that absorbs harmful blue light from LED chips and converts it to safer visible wavelengths. This intermediary layer protects human eyes from blue light leakage while maintaining accurate color rendering through controlled phosphor composition and distribution.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Stability of the object's composition

If rigid packaging is used for LED assemblies, then structural stability is improved, but flexibility and ease of storage are reduced

Engineering Contradiction:

Improvestructural stabilityVSAvoidflexibility and storage

Core Design Contradiction:

Stability of the object's compositionVSEase of operation

Solution Approach 1:

The patent replaces traditional rigid packaging with a flexible transparent substrate that maintains structural integrity while enabling bending and conformal mounting. This flexible shell provides adequate mechanical protection and structural stability while dramatically improving ease of storage, transport, and adaptation to various lighting application geometries.

Inventive Principle:

Principle #30Flexible shells and thin films

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 reduces blue light leakage, maintains light emission in all directions, facilitates easy storage and assembly, and supports adjustable voltage and length, making it suitable for omnidirectional lighting applications with enhanced reliability and safety.

Implementation Method 1

A white LED could be provided by using phosphor to convert a portion of the blue light from a blue LED chip into green/yellow light, such that the mixture of the lights is perceived as white light by human eyes.

Methodology Applied

Scientific EffectPhosphorescence: Phosphorescence

Implementation Method 2

Optical design, such as the way to extract and direct the light into a preferable angle or distribution, also plays an important role for LED packaging.

Methodology Applied

Scientific EffectLight extraction: Refraction

Data Source

PatentUSRE49031E1Flexible LED assemblies and LED light bulbs

Publication Date: 2022.04.12 ENNOSTAR CORP

AI summary

LED assemblies and related LED light bulbs. An LED assembly has a flexible, transparent substrate, an LED chip on the first surface and electrically connected to two adjacent conductive sections, a first wavelength conversion layer, formed on the first surface to substantially cover the LED chip, and a second wavelength conversion layer formed on the second surface. The flexible, transparent substrate has first and second surfaces opposite to each other, and several conductive sections, which are separately formed on the first surface.