Light-Emitting Element Barrier Layer Prevents Metal Migration
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Solution Overview
Problem
Light emitting devices face issues with metal migration from the reflective layer, leading to reduced light output and reliability due to moisture infiltration, which existing technologies have not adequately addressed.
Innovation Solution
Incorporating a barrier layer outside the reflective layer to prevent metal migration and moisture ingress, enhancing the device's moisture resistance and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a reflective layer is disposed under the light emitting structure to improve light extraction efficiency, then light output is enhanced, but metal migration occurs leading to reduced reliability
Solution Approach 1:
A barrier layer is introduced as an intermediary component between the reflective layer and the light emitting structure. This barrier layer prevents direct contact and interaction between the reflective layer materials and the light emitting structure, thereby stopping metal migration while preserving the light reflection function. The barrier layer acts as a mediator that maintains the beneficial optical properties while eliminating the harmful migratory behavior of metal atoms.
Solution Approach 2:
The electrode structure is segmented into multiple distinct layers: the reflective layer, the barrier layer, and the light emitting structure. By dividing what could be a single integrated component into separate functional layers, the patent isolates the metal migration issue to a specific interface and prevents it from affecting the overall device performance. The barrier layer segment specifically addresses the migration problem without compromising the reflective function.
2Device complexity
If the reflective layer is in direct contact with the light emitting structure to simplify device structure, then manufacturing is easier, but moisture infiltration occurs causing metal migration
Solution Approach 1:
The barrier layer serves as an intermediary protective layer between the reflective layer and the light emitting structure, specifically designed to block moisture infiltration. This intermediary layer prevents harmful moisture from reaching the reflective layer and causing metal migration, while maintaining a relatively simple overall device structure that can be integrated into existing manufacturing processes.
3Productivity
If no barrier layer is used to reduce manufacturing steps, then production efficiency is higher, but metal migration reduces light output
Solution Approach 1:
The barrier layer is applied in advance during the manufacturing process, before the light emitting structure is fully assembled and before metal migration can occur. This preliminary protective action ensures that the reflective layer is pre-protected against moisture infiltration and subsequent metal migration, preserving light output performance without requiring additional corrective steps after device assembly.
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 barrier layer effectively prevents metal migration and moisture infiltration, maintaining light output and improving the reliability of the light emitting device package.
Implementation Method 1
a barrier layer on an outer peripheral portion of the reflective layer... which blocks the material constituting the reflecting layer from being migrated
Implementation Method 2
The embodiment may provide a light emitting device strong for moisture... The barrier layer effectively prevents metal migration and moisture infiltration
Implementation Method 3
a reflective layer as a part of a first electrode layer below the light emitting structure... a reflective layer and a barrier layer, which blocks the material constituting the reflecting layer
Data Source
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AI summary
Disclosed in an embodiment is a light emitting device comprising: a light-emitting structure having a first semiconductor layer, an active layer under the first semiconductor layer, and a second semiconductor layer under the active layer; a first contact layer disposed under the light-emitting structure; a reflective layer disposed under the first contact layer; a first electrode layer including a capping layer disposed under the reflective layer; a second electrode layer electrically connected with the first semiconductor layer; a protective layer disposed at the outer peripheral portion between the capping layer and the light-emitting structure; a barrier layer at an outer side of the reflective layer and made of a metal different from that of the reflective layer; and a support member disposed under the capping layer.