Black EMC LED Package Rigidity and Light Extraction

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Solution Overview

Problem

Conventional light emitting device packages face issues with rigidity, high manufacturing costs, and inadequate light extraction efficiency due to the use of ceramic or AlN substrates, which are prone to cracking and have unstable injection molding and processability.

Innovation Solution

A light emitting device package is designed with a body made of black epoxy molding compound containing carbon black, featuring first and second lead frames electrically separated by the body, and a molding member surrounding the light emitting device to enhance rigidity and light extraction efficiency, while using a white inner EMC for reflectivity and a black outer EMC for increased rigidity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a ceramic substrate is used in the light emitting device package, then the manufacturing cost increases, but the rigidity and structural stability are improved

Engineering Contradiction:

ImproverigidityVSAvoidmanufacturing cost

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent changes the material parameter from ceramic to epoxy molding compound (EMC), which has different mechanical and thermal properties. This substitution reduces manufacturing cost while maintaining adequate rigidity through optimized package structure design

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite material structure combining EMC body with metal lead frames and semiconductor components. This composite approach provides the necessary rigidity and structural stability without requiring expensive ceramic substrates

Inventive Principle:

Principle #40Composite materials

2Reliability

If a ceramic substrate is used in the light emitting device package, then the manufacturing cost increases, but the structural stability is improved

Engineering Contradiction:

Improvestructural stabilityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the substrate material parameter from ceramic to EMC, reducing cost while compensating for structural stability through optimized package geometry and metal component integration

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent adopts the successful package structure design from conventional LED packages (using EMC instead of ceramic) and adapts it for high-power LED applications, proving that ceramic is not essential for structural stability

Inventive Principle:

Principle #26Copying

3Ease of manufacture

If the outer periphery of the light emitting device package is made less rigid, then the manufacturing cost decreases, but the susceptibility to cracking increases

Engineering Contradiction:

Improvemanufacturing costVSAvoidcracking resistance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent uses EMC material which has appropriate flexibility and shock absorption properties, reducing stress concentration at the package periphery and preventing cracking while maintaining cost-effectiveness

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The EMC body acts as a cushioning element that absorbs thermal and mechanical stress before it can propagate to the semiconductor components, preventing cracking without requiring rigid ceramic structures

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

4Strength

If a black EMC containing carbon black is used for the body, then the rigidity is improved, but the light extraction efficiency may be affected

Engineering Contradiction:

ImproverigidityVSAvoidlight extraction efficiency

Core Design Contradiction:

StrengthVSIllumination intensity

Solution Approach 1:

The patent applies different material properties to different regions: black EMC with carbon black is used for the body requiring rigidity and heat dissipation, while the molding member surrounding the LED chip is designed to optimize light extraction, creating local quality differentiation

Inventive Principle:

Principle #3Local quality

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 results in a more cost-effective, rigid, and efficiently processable light emitting device package with improved heat dissipation and reduced risk of cracking, enabling higher production volumes and better light extraction efficiency.

Implementation Method 1

a body (110) including a black epoxy molding compound (EMC) containing carbon black

Methodology Applied

Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 2

using a white inner EMC for reflectivity

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentEP3416202B1Light emitting device package and lighting apparatus comprising same

Publication Date: 2021.04.07 SUZHOU LEKIN SEMICON CO LTD

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AI summary

A light emitting device of an embodiment includes a body including a black epoxy molding compound (EMC) including carbon black; first and second lead frames electrically separated from each other by the body; a light emitting device disposed above at least one of the first or second lead frame; and a molding member disposed above the body and the first and second lead frames so as to surround the light emitting device.