LED Reflective Layer Layout for Brightness Without Current Leakage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional light-emitting diodes face challenges in enhancing brightness while maintaining reliability due to limitations in the design of reflective layers and insulating structures, which can lead to current leakage and reduced efficiency.
Innovation Solution
The design incorporates a reflective structure with a reflective layer that does not extend beyond the edges of the semiconductor stack, combined with a transparent conductive layer and insulating structures to prevent current leakage, enhancing brightness while maintaining reliability by optimizing the area of the reflective layer and insulating coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the reflective layer area is increased to enhance light reflection and brightness, then the brightness is improved, but the risk of current leakage through the insulating structure increases
Solution Approach 1:
The reflective layer is divided into a first reflective layer and a second reflective layer with different materials and functions. The first reflective layer (high reflectivity material like Ag or Al) focuses on light reflection, while the second reflective layer (low resistance material like Cu or Al) focuses on current conduction and provides insulation protection, separating the conflicting requirements of light reflection and current leakage prevention into different functional zones.
Solution Approach 2:
The patent extends the reflective structure into the third dimension by forming a side surface reflective layer that covers the side surfaces of the semiconductor stack. This vertical extension allows the reflective layer to reflect light from multiple angles and increases the effective reflective area without expanding the horizontal footprint that would compromise insulating coverage.
2Loss of energy
If the reflective layer extends beyond the semiconductor stack edges to maximize light reflection area, then the light reflection efficiency is improved, but the insulating structure must be extended accordingly increasing device complexity
Solution Approach 1:
The reflective layer is designed to extend partially beyond the semiconductor stack edges (first extension amount) but not excessively. The insulating layer extends by a second amount that is greater than the first extension amount, providing sufficient insulation coverage without requiring the entire device structure to be expanded proportionally, thus balancing light reflection needs with insulating coverage.
3Device complexity
If a single-layer reflective structure is used to simplify the device structure, then the device complexity is reduced, but the ability to simultaneously achieve high reflectivity and current conduction is compromised
Solution Approach 1:
The reflective structure uses a composite multi-layer design where the first reflective layer employs high reflectivity materials (Ag, Al, or their alloys) optimized for light reflection, while the second reflective layer uses low resistance materials (Cu, Al, or their alloys) optimized for current conduction. This composite structure allows each layer to perform its specialized function, achieving both high light emission efficiency and reliable current conduction that a single-layer structure cannot provide.
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 increases the brightness of the light-emitting diode by enhancing light reflection without compromising reliability, as the reflective layer's larger area effectively reflects more light without causing electrical shorts through the insulating structures.
Implementation Method 1
a reflective structure located on the second semiconductor layer and including an outer edge... the reflective layer's larger area effectively reflects more light
Data Source
AI summary
A light-emitting device includes a semiconductor structure including a first semiconductor layer, a second semiconductor layer on the first semiconductor layer, and an active layer between the first semiconductor layer and the second semiconductor layer, wherein the second semiconductor layer includes a first edge; a reflective structure located on the second semiconductor layer and including an outer edge; a first electrode pad located on the reflective structure, wherein the first electrode pad including an outer side wall adjacent to the outer edge, wherein the outer edge extends beyond the outer side wall and does not exceed the first edge in a cross-sectional view of the light-emitting device.