Resin Frame Recess for Thermal Stress Dispersion in LED Substrates

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Solution Overview

Problem

As the luminance of light emitting elements increases, they generate significant heat upon activation, causing the encapsulant to expand and potentially detach from the mounting substrate due to thermal stress.

Innovation Solution

A light-emitting-element mounting substrate with a resin frame surrounding the mount portion and featuring a recess on its surface, which disperses thermal stress perpendicular to the substrate, preventing encapsulant removal during expansion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the luminance of light emitting elements is increased, then the light emission efficiency is improved, but the heat generation increases causing the encapsulant to expand and detach from the mounting substrate

Engineering Contradiction:

ImproveluminanceVSAvoidencapsulant attachment

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The resin frame includes a recess that extends in the thickness direction (perpendicular to the substrate surface), creating a three-dimensional stress dispersion structure. This allows thermal expansion stress to be distributed throughout the volume of the resin frame rather than concentrated at the interface between encapsulant and substrate, preventing detachment while maintaining high luminance operation

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If the encapsulant is made to fully cover the mount portion for complete protection, then the protection effectiveness is improved, but the thermal expansion stress concentrates causing easier removal

Engineering Contradiction:

Improveencapsulant protectionVSAvoidencapsulant position

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The resin frame is configured with different regions having different functions: the recess region provides stress dispersion and encapsulant retention, while the protruding regions provide structural support and stress distribution. This localized functional differentiation allows the encapsulant to be fully protective without concentrating stress that would cause removal

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

This design effectively suppresses encapsulant removal and allows for efficient, long-term light emission by managing thermal expansion stress within the resin frame.

Implementation Method 1

the light emitting element generates a large amount of heat. The heat is transferred to the encapsulant and causes the encapsulant to expand

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS10174914B2Light-emitting-element mounting substrate, light emitting device, and light emitting module

Publication Date: 2019.01.08 KYOCERA CORP

AI summary

A light-emitting-element mounting substrate according to the present invention includes a substrate, a mount portion for mounting a light emitting element on a main surface of the substrate, and a resin frame surrounding the mount portion in plan view and to be in contact with an encapsulant for encapsulating the light emitting element to be mounted. The resin frame includes a recess in a main surface thereof, the recess surrounding the mount portion in plan view.