LED Electrode Structure with Integrated Current Blocking and Passivation
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Solution Overview
Problem
Conventional light emitting devices (LEDs) require a separate process for forming a passivation layer, increasing manufacturing time and cost, and have limitations in light extraction efficiency.
Innovation Solution
A light emitting device design that incorporates a current blocking layer serving as both a passivation layer and a distributed Bragg reflector, along with conductive interconnection and electrode layers without reflection layers, to enhance light extraction efficiency and reduce manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate passivation layer is formed in conventional LEDs, then electrical separation and protection are achieved, but manufacturing time and cost increase
Solution Approach 1:
The patent combines the passivation layer and current blocking layer into a single integrated structure. The current blocking layer is formed to extend from between the upper electrode and upper semiconductor layer to between adjacent light emitting cells and the conductive interconnection layer, simultaneously providing electrical separation and current blocking functions without requiring a separate passivation layer formation process.
Solution Approach 2:
The current blocking layer serves multiple functions: it blocks current leakage between adjacent light emitting cells, provides electrical separation, and acts as a structural support. This multi-functional design eliminates the need for dedicated passivation layers while maintaining all necessary electrical isolation functions.
2Reliability
If conventional LED structures with separate passivation layers are used, then electrical isolation is achieved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent merges the passivation function into the current blocking layer structure. The current blocking layer is configured to extend across multiple regions, providing both current blocking and passivation functions in a single structural element, thereby reducing the number of separate layers and manufacturing steps.
3Reliability
If traditional electrode structures with reflection layers are used, then electrical connection is achieved, but light extraction efficiency decreases
Solution Approach 1:
The patent removes the reflection layer from the electrode structure. The electrode is designed to provide electrical connection without incorporating reflective materials, thereby eliminating the trade-off between electrical connectivity and light extraction efficiency that exists in conventional designs.
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 solution reduces manufacturing time and cost while improving light extraction efficiency and corrosion resistance, making it suitable for exterior lighting applications.
Implementation Method 1
a current blocking layer disposed so as to extend from between an upper electrode and an upper semiconductor layer of a second light emitting cell to between adjacent light emitting cells and a conductive interconnection layer
Implementation Method 2
a conductive interconnection layer configured to electrically connect a lower electrode of a first one of adjacent ones of the light emitting cells and an upper electrode of a second one of the adjacent light emitting cells
Implementation Method 3
a current blocking layer serving as both a passivation layer and a distributed Bragg reflector
Data Source
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AI summary
A light emitting device includes a substrate, light emitting cells , each of the light emitting cells including a light emitting structure including lower and upper semiconductor layers, an upper electrode, and a lower electrode, a conductive interconnection layer electrically connecting a lower electrode of a first one of the light emitting cells and an upper electrode of a second one of the light emitting cells, and a current blocking layer disposed to extend from between the upper electrode and the upper semiconductor layer, wherein each light emitting cell further includes a conductive layer arranged to electrically connect the upper electrode of the second light emitting cell to the upper semiconductor layer of the second light emitting cell.