LED Package Sloped Edge Mitigates Thermal Delamination

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Solution Overview

Problem

Light emitting device packages face delamination issues due to thermal deformation, which existing technologies have not effectively addressed, leading to potential failures and reduced reliability.

Innovation Solution

A light emitting device package design that incorporates a substrate with a formation layer featuring a slope at its edge portion, angled between 25° to 70°, to mitigate thermal deformation and prevent delamination, using methods such as bevel blades, laser cutting, or etching to form the slope, and employing materials like reflective and transparent layers for enhanced durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a formation layer is formed on a substrate without edge modification, then the manufacturing process is simple, but thermal deformation causes delamination at the edge portions

Engineering Contradiction:

Improvedelamination preventionVSAvoidformation layer structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies curvature by forming a slope at the edge portion of the formation layer instead of a sharp corner. This rounded/angled transition reduces stress concentration and prevents delamination caused by thermal deformation during LED operation. The slope angle is specifically controlled to be between 45° and 60° to optimize the stress distribution.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Reliability

If the edge portion of the formation layer is modified with a slope, then delamination is prevented, but the manufacturing process becomes more complex

Engineering Contradiction:

Improveformation layer adhesionVSAvoidslope formation process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The slope is formed preliminarily during the formation layer deposition process itself, rather than requiring a separate post-processing step. This is achieved by controlling the deposition parameters or using a molding technique that directly creates the sloped edge, thereby preventing delamination while minimizing additional manufacturing complexity.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If the slope angle is increased to better prevent delamination, then adhesion improves, but manufacturing precision requirements increase

Engineering Contradiction:

Improvethermal deformation resistanceVSAvoidslope angle control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent optimizes the slope angle parameter to a specific range (45°-60°) that balances delamination prevention with manufacturability. This parameter optimization ensures sufficient stress distribution improvement while remaining within the capabilities of standard manufacturing processes, avoiding excessive precision requirements.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9337386B2Light emitting device package

Publication Date: 2016.05.10 SAMSUNG ELECTRONICS CO LTD

AI summary

A light emitting device package is provided. The light emitting device includes: a substrate; a light emitting device disposed at one side of the substrate; and a formation layer formed on the substrate and having a slope at an edge portion of the formation layer.