Light Emitting Device Conductive Patterns for Reliable Connections
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Solution Overview
Problem
Existing light emitting devices face issues with reliable connections over extended periods due to poor conductivity in high-voltage applications, particularly in the combination of conductive pattern shapes and materials with external power supplies.
Innovation Solution
The use of an element mounting board with conductive patterns featuring a first and second conductive layer made of different materials, where the first layer is exposed on element mounting areas and the second layer is used for external connections, enhancing adhesion and connection reliability by using gold for the first layer and aluminum for the second layer, respectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-material conductive pattern is used for both element mounting and external connection, then the structure is simple, but connection reliability deteriorates under high voltage over extended periods
Solution Approach 1:
The conductive pattern is segmented into two distinct layers: a first conductive layer (e.g., aluminum) for element mounting areas, and a second conductive layer (e.g., copper) for external connection areas. This segmentation allows each layer to be optimized for its specific function, preventing the reliability issues that arise from using a single material for both purposes.
Solution Approach 2:
Different materials are applied to different regions of the conductive pattern based on local requirements. The first conductive layer uses aluminum suitable for element mounting, while the second conductive layer uses copper with superior conductivity for external connections. This local quality differentiation ensures optimal performance in each region while maintaining overall connection reliability.
2Reliability
If gold is used for the first conductive layer in element mounting areas, then adhesion between light emitting elements and mounting board is improved, but manufacturing cost increases
Solution Approach 1:
Gold is applied locally only to the first conductive layer in element mounting areas where superior adhesion is critical for reliable electrical connection. The second conductive layer for external connections uses more cost-effective materials like copper. This localized application of expensive materials minimizes cost while maintaining adhesion strength where it matters most.
Solution Approach 2:
The conductive pattern uses composite material construction with multiple layers of different materials. The first layer combines gold with aluminum, while the second layer uses copper or other conductive materials. This composite structure achieves the adhesion benefits of gold where needed while using more economical materials in other areas, reducing overall material cost.
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 ensures stronger and more secure adhesion between light emitting elements and the mounting board, as well as between external power supplies and the board, maintaining reliable connections even under high voltage conditions over an extended period.
Implementation Method 1
ensures stronger and more secure adhesion between light emitting elements and the mounting board
Implementation Method 2
The conductive patterns each include a first conductive layer and a second conductive layer that is made of a different material from a material of the first conductive layer
Data Source
AI summary
A light emitting device includes: an element mounting board having a base and conductive patterns disposed on a main surface of the base, and each having one or more element mounting areas and one or more external connection areas; conductive patterns each having first and second conductive layers which is made of a different material from that of the first conductive layer, and disposed in this order starting from the base side; element mounting areas, on which the light emitting elements are mounted, having the first conductive layer that is not covered by the second conductive layer; external connection areas having the first conductive layer in which an outer edge is exposed from the second conductive layer; a light reflecting component integrally covers the element mounting areas and lateral surfaces of the light emitting elements; and a light-transmissive component exposing the external connection areas.