Light Emitting Module Resin Coating for Silver Wiring Migration

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Solution Overview

Problem

The existing light emitting modules face issues with migration of wiring patterns made of silver under high humidity conditions, leading to potential short circuits, especially in miniaturized vehicles' lighting devices, which also increases manufacturing costs due to the need for separate resin coatings.

Innovation Solution

Incorporating a surrounding wall member with a resin joining portion and additional resin-based coating portions to cover exposed wiring patterns and soldered elements, minimizing migration and reducing manufacturing costs by using the same resin for multiple components, such as the sealing and coating portions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate coating step of resin is provided to cover the exposed portion of the wiring pattern, then the occurrence of migration can be minimized, but manufacturing cost may increase

Engineering Contradiction:
Improveoccurrence of migrationVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines the coating resin with the sealing resin into a single material system. The sealing resin that is already applied to seal the light emitting element is formulated to also provide coating protection for the exposed wiring pattern, eliminating the need for a separate coating step and reducing manufacturing cost while maintaining migration protection

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The sealing resin is given dual functionality: it serves both as a sealing material for the light emitting element and as a coating material for protecting the exposed wiring pattern from migration. This multi-functional approach eliminates the need for separate coating materials and processes

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

2Ease of manufacture

If the wiring pattern is exposed, then manufacturing process is simpler, but migration may occur under high humidity condition

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidmigration resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent modifies the chemical composition and properties of the sealing resin to ensure it provides both sealing and coating functions. By adjusting the resin's formulation parameters, it achieves appropriate viscosity, adhesion, and protective properties to prevent migration while maintaining ease of application

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2991464B1Light emitting module and lighting device
Publication Date: 2020.04.15 TOSHIBA LIGHTING & TECHNOLOGY CORP
  • EP2991464B1 patent drawingFigure 1~2
  • EP2991464B1 patent drawingFigure 3

AI summary

A light emitting module according to an exemplary embodiment includes a board that is provided with a wiring pattern, a light emitting element that is electrically connected to the wiring pattern, a surrounding wall member that is provided on the board via a joining portion containing a resin and surrounds the light emitting element, and a first coating portion that contains the same resin as the resin contained in the joining portion, and covers an exposed portion of the wiring pattern outside the surrounding wall member.