Textured Encapsulant Interface for LED Light Extraction

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Solution Overview

Problem

Existing solid state lighting devices with multiple encapsulant layers face challenges in enhancing adhesion between layers, controlling optical properties, and increasing light extraction and color mixing efficiency.

Innovation Solution

The use of a lighting device with a textured interface between layers, featuring protruding portions and recesses of specific heights and depths, composed of different encapsulant materials, to improve adhesion and optical control, and enhance light extraction and color mixing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple encapsulant layers with different indices of refraction are used, then light extraction efficiency is improved, but adhesion between layers deteriorates

Engineering Contradiction:

Improvelight extraction efficiencyVSAvoidadhesion between layers

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

The encapsulant structure is divided into multiple discrete layers with different indices of refraction (first encapsulant layer with index n1, second encapsulant layer with index n2 where n1 ≠ n2). This segmentation enables progressive light extraction at each interface, improving overall extraction efficiency while maintaining layer integrity through the textured interface design.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A textured interface featuring protruding portions and recesses is introduced between the encapsulant layers. This curved/non-planar interface increases the surface area for adhesion and creates multiple light extraction paths, simultaneously improving both adhesion strength and light extraction efficiency compared to a flat interface.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Adaptability or versatility

If encapsulant layers with different compositions are used, then optical control is improved, but manufacturing complexity increases

Engineering Contradiction:

Improveoptical controlVSAvoidmanufacturing complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Different encapsulant materials with specific optical properties (different indices of refraction) are assigned to specific layers based on their functional requirements. The first encapsulant layer is optimized for light extraction from the LED chip, while the second layer is optimized for light emission to the external environment, enabling precise optical control at each stage.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The textured interface with protruding portions and recesses is integrated into the manufacturing process as a standard feature, allowing the different encapsulant materials to be applied in sequence. This design enables optical control versatility while maintaining manageable manufacturing complexity through established multi-layer deposition techniques.

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Productivity

If a textured interface is added between encapsulant layers, then light extraction is enhanced, but manufacturing precision requirements increase

Engineering Contradiction:

Improvelight extractionVSAvoidinterface texture precision

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The interface between encapsulant layers is designed with a textured profile featuring protruding portions and recesses instead of a flat surface. This curvature/texturing increases light extraction by reducing Fresnel reflection and creating multiple extraction angles, while the specific geometric features can be controlled within standard manufacturing tolerances.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The combination of different encapsulant materials with a textured interface creates a composite structure that leverages the optical properties of each material while the textured interface provides enhanced light extraction. This composite approach allows the use of materials optimized for their specific functions without requiring extreme manufacturing precision.

Inventive Principle:

Principle #40Composite materials

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 textured interface between encapsulant layers in the lighting device enhances adhesion, optical control, and light extraction, allowing for improved color mixing and tailored performance in LED lighting devices.

Implementation Method 1

reduce Fresnel reflection at the encapsulant/air interface

Methodology Applied

Scientific EffectFresnel reflection: Reflection

Implementation Method 2

textured interface between the first layer and the second layer

Methodology Applied

Scientific EffectLight scattering: Scattering

Implementation Method 3

multiple layers of materials (e.g., silicone, epoxy, hybrid silicone/epoxy materials) having different indices of refraction

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS8946747B2Lighting device including multiple encapsulant material layers

Publication Date: 2015.02.03 CREELED INC

AI summary

A lighting device includes an electrically activated emitter, a first layer that contains a first encapsulant material, and a second layer that contains a second encapsulant material, with a textured interface between the first layer and the second layer. Additional layers including further encapsulant materials and/or lumiphoric materials may be provided. Multiple textured interfaces may be provided. Textured interfaces may be arranged as lenses, including Fresnel lenses.