Radial Wire Light Emitting Device Thermal Stress

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Solution Overview

Problem

Current light emitting devices with multiple light emitting chips face challenges in heat radiation efficiency and electrical reliability, particularly due to the complex arrangement of metal layers, bonding regions, and wire connections which can lead to disconnection under thermal expansion and contraction.

Innovation Solution

A light emitting device design featuring a body with first and second metal layers, a heat radiation plate, and a molding member, where light emitting parts are connected via wires arranged radially to the center, with specific support protrusions and gap parts to enhance heat radiation and electrical reliability by minimizing tensile forces during thermal deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple light emitting chips are connected with complex wire arrangements, then electrical connectivity is achieved, but reliability deteriorates due to disconnection under thermal expansion and contraction

Engineering Contradiction:
Improveelectrical reliabilityVSAvoidwire arrangement complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The device segments the light emitting components into modular parts, each with simplified wire connections to the heat radiation plate. This segmentation reduces the overall complexity of wire arrangements while maintaining electrical connectivity across multiple light emitting chips.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs a flexible molding member that covers and protects the wire connections. This flexible structure accommodates thermal expansion and contraction without causing wire disconnection, thereby improving reliability while keeping the wire arrangement simple.

Inventive Principle:
Principle #30Flexible shells and thin films

2Volume of moving object

If metal layers are closely arranged to reduce device size, then compactness is improved, but heat radiation efficiency deteriorates

Engineering Contradiction:
Improvedevice volumeVSAvoidheat radiation efficiency
Core Design Contradiction:
Volume of moving objectVSTemperature

Solution Approach 1:

The heat radiation plate features locally optimized structures with support protrusions and gap parts positioned at specific locations. These local structural variations enhance heat radiation efficiency in critical areas without significantly increasing the overall device volume.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent utilizes the vertical dimension by creating gap parts between metal layers and the heat radiation plate. This dimensional approach allows heat to dissipate more effectively through the vertical space without expanding the horizontal footprint of the device.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If support structures are added to reduce thermal stress, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvethermal stress resistanceVSAvoidsupport structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The support protrusions on the heat radiation plate serve multiple functions: they provide mechanical support for the metal layers, create thermal management gaps, and reduce thermal stress. This multi-functionality improves reliability without adding separate support structures that would increase complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the support function with the heat radiation plate itself by integrating support protrusions into its structure. This combination eliminates the need for separate support components, thereby improving thermal stress resistance without increasing overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

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 design improves heat radiation efficiency and electrical reliability by reducing the impact of thermal expansion on wire connections, leading to increased durability and reduced failure rates over multiple cycles.

Implementation Method 1

a heat radiation plate disposed between the first and second metal layers

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a light emitting device comprises a body; first and second metal layers on a top surface of the body... a plurality of light emitting parts on the heat radiation plate

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP2996164B1Light emitting device
Publication Date: 2021.06.16 SUZHOU LEKIN SEMICON CO LTD
  • EP2996164B1 patent drawingFigure 1
  • EP2996164B1 patent drawingFigure 2~3
  • EP2996164B1 patent drawingFigure 4~5

AI summary

Disclosed is a light emitting device. The light emitting device includes a body, first and second metal layers on a top surface of the body, a heat radiation plate disposed between the first and second metal layers and having a circular outline, a plurality of light emitting parts on the heat radiation plate, first and second bonding regions disposed on the first and second metal layers and electrically connected with the light emitting parts, and a molding member disposed on the heat radiation plate to cover the light emitting parts. Each of the light emitting parts includes a plurality of light emitting chips connected with each other, and a plurality of wires to electrically connect the light emitting chips with the first and second bonding regions, and the wires of each light emitting part are arranged a radial direction about a central of the heat radiation plate.