LED Sulfurization Prevention via Segmented Resin and Light Shielding
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Solution Overview
Problem
Light emitting diodes (LEDs) with nitride-based semiconductors face issues with sulfurization of silver conductive members due to gas permeability, leading to potential wire disconnection, as existing protective films struggle to cover the connecting portions effectively.
Innovation Solution
A light emitting device design incorporating a base member with a conductive silver member, a protective film, and resin members with varying gas barrier properties, where a first resin member with high gas barrier properties covers the connecting portion and contains light reflecting particles to prevent sulfurization, and a second resin member with lower gas barrier properties covers the light emitting element, while a light shielding portion reduces direct light exposure to the first resin member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective film is formed by sputtering to cover the conductive member, then sulfurization of the silver conductive member is prevented, but the connecting portion cannot be effectively covered due to geometric constraints
Solution Approach 1:
The protective structure is divided into two segments: a protective film formed by sputtering that covers the main body of the conductive member, and a resin member that fills the recess and covers the connecting portion. This segmentation allows each component to perform its protective function effectively without geometric constraints limiting coverage.
Solution Approach 2:
The resin member is nested within the recess of the base member, creating a layered protective structure where the resin member contains the connecting portion and works in conjunction with the protective film. This nesting approach ensures complete coverage of all vulnerable areas including the connecting portion.
2Reliability
If resin material is used to cover the connecting portion, then complete coverage is achieved, but the resin deteriorates under direct light exposure from the light emitting element
Solution Approach 1:
The light emitting element is extracted from direct contact with the resin member by positioning it on the conductive member rather than within the resin. This spatial separation removes the harmful direct light exposure from the resin while maintaining the protective coverage of the connecting portion.
Solution Approach 2:
The conductive member serves as an intermediary structure that supports the light emitting element at a position where it does not directly illuminate the resin member. This intermediary positioning protects the resin from deterioration while maintaining structural integrity and coverage.
3Productivity
If the light emitting element is positioned to maximize light output, then luminous efficiency is improved, but the resin member covering the connecting portion is exposed to direct light causing deterioration
Solution Approach 1:
The base member is designed with a localized recess structure that provides differential protection: the resin member fills the recess to protect the connecting portion from sulfurization, while the light emitting element is positioned on the conductive member to maximize light output without directly illuminating the resin. This local structural differentiation resolves the contradiction between light output and resin stability.
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 configuration enhances the durability and reliability of the LED by preventing sulfurization and disconnection of the wire, improving light extraction efficiency and maintaining output while reducing resin deterioration.
Implementation Method 1
the resin is permeable to gas, which allows the metal members to be sulfurized and deteriorated with use
Implementation Method 2
The first resin member contains first light reflecting particles to reflect light emitted by the light emitting element
Implementation Method 3
The light shielding portion is disposed on at least a portion of a surface of the base member. The light shielding portion is disposed on a line connecting the light emitting element and the first resin member
Data Source
AI summary
A light emitting device includes a base member, a light emitting element, a wire, a protective film, first and second resin members, and a light shielding portion. The base member has a conductive member. The wire connects the light emitting element and the conductive member. The protective film covers the conductive member to be spaced apart from a portion of a connecting portion. The first resin member continuously covers at least a portion of each of the protective film, a portion of the conductive member around the connecting portion, and the wire. The first resin member contains first light reflecting particles to reflect light emitted by the light emitting element. The second resin member covers the light emitting element and the first resin member. The light shielding portion is disposed on the base member and disposed on a line connecting the light emitting element and the first resin member.