LED Light Extraction via Active-Reflective Layer Distance Optimization
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Solution Overview
Problem
Conventional light emitting diodes (LEDs) face challenges in achieving high light extraction efficiency due to limitations in the interference patterns between the active layer and the reflective layer, leading to suboptimal light extraction and reduced efficiency.
Innovation Solution
The LED design optimizes the distance between the active layer and the reflective layer to satisfy specific interference conditions, allowing for constructive interference, which enhances light extraction efficiency by adjusting the phase change values and layer thicknesses to maximize light extraction through the top surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the distance between the active layer and the reflective layer is not optimized, then the device structure is simpler, but the light extraction efficiency is reduced
Solution Approach 1:
The patent optimizes the distance parameter between the active layer and reflective layer to satisfy specific interference conditions. By adjusting this distance parameter to meet the formula 2nh = (m + 0.5)λ, the system achieves constructive interference that maximizes light extraction efficiency without requiring complex structural modifications.
Solution Approach 2:
The patent employs periodic interference patterns created by the reflective layer at optimized distances to enhance light extraction. The periodic nature of the interference conditions (satisfied at specific distance intervals) allows for systematic optimization of light extraction efficiency while maintaining relatively simple device structure.
2Ease of manufacture
If the phase change values and layer thicknesses are not adjusted, then the manufacturing process is simpler, but the light extraction pattern is suboptimal
Solution Approach 1:
The patent adjusts the phase change values and layer thicknesses to satisfy specific interference conditions. By changing these parameters to meet the interference formula, the system achieves optimized light extraction patterns with enhanced vertical light extraction while maintaining a manufacturing process that does not require fundamentally new techniques.
3Device complexity
If the interference conditions are not optimized, then the device structure is simpler, but the light extraction efficiency is reduced
Solution Approach 1:
The patent optimizes the device structure by adjusting the distance between layers to satisfy interference conditions. This parameter optimization enhances light extraction efficiency without introducing significant structural complexity, as the solution relies on precise dimensional control rather than additional components or complex architectures.
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 significantly improves light extraction efficiency by increasing the quantity of light extracted vertically, optimizing the light extraction pattern, and minimizing losses, resulting in enhanced performance of the LED.
Implementation Method 1
a reflective layer 158 on the conductive support member 160
Implementation Method 2
a light emitting structure 145 including a first conductivity type semiconductor layer 130, an active layer 140, and a second conductivity type semiconductor layer 150
Data Source
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AI summary
Disclosed are a light emitting device, a light emitting device package, and a lighting system. The light emitting device includes a conductive support member; a reflective layer on the conductive support member; a light emitting structure on the reflective layer including a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer between the first and second semiconductor layers; and an electrode on the first conductive semiconductor layer, wherein a distance between the active layer and the reflective layer satisfies 2 • Φ1+Φ3 = N • 2Π±Δ, (0≤Δ≤Π/2) in which the Φ1 represents a phase change value when light vertically traveling passes through the second conductive semiconductor layer, the Φ3 represents a phase change value when the light is reflected by the reflective layer, and the N represents a natural number, and wherein the distance between the reflective layer and the active layer includes a first distance in a first region overlapping with the electrode perpendicularly to the electrode and a second distance in a second region other than the first region, the first distance being different from the second distance.