LED Extraction Layer Dipole Orientation
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Solution Overview
Problem
Existing light-emitting diodes (LEDs) face challenges in achieving improved luminous efficacy due to limitations in the orientation and coupling of emitting dipoles, which affect the efficiency of radiative recombination and light extraction.
Innovation Solution
A method involving a semiconductor stack with an extraction layer made of transparent dielectric material containing nanoscale particles, where the emitting dipoles are oriented vertically to enhance non-radiative coupling, optimizing the distance between emitting dipoles and the extraction layer to prolong their lifetime and improve light extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the emitting dipoles are oriented horizontally in conventional LEDs, then the device structure is simpler, but the light extraction efficiency is reduced
Solution Approach 1:
The patent changes the orientation parameter of emitting dipoles from horizontal to vertical by adjusting the distance between the active layer and extraction layer, thereby improving light extraction efficiency without fundamentally changing the device structure
Solution Approach 2:
The patent introduces dynamic control of dipole orientation through adjustable distance parameters, allowing the system to optimize between structural simplicity and light extraction efficiency based on specific design requirements
2Duration of action of moving object
If the distance between emitting dipoles and extraction layer is increased, then the dipole lifetime is prolonged, but the coupling efficiency decreases
Solution Approach 1:
The patent optimizes the distance parameter between emitting dipoles and extraction layer to achieve a balance where dipole lifetime is sufficiently prolonged while maintaining effective near-field coupling, thereby resolving the trade-off between these two parameters
3Loss of energy
If vertical orientation of emitting dipoles is achieved through precise distance control, then luminous efficacy is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent identifies specific distance ranges that enable vertical dipole orientation and improved luminous efficacy, providing clear manufacturing guidelines that balance performance improvement with achievable precision requirements
Solution Approach 2:
The patent replaces complex mechanical alignment systems with distance-based optical field control, using the extraction layer positioning to achieve vertical dipole orientation through electromagnetic field interactions rather than mechanical constraints
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 method significantly enhances the luminous efficacy of LEDs by promoting vertical orientation of emitting dipoles, leading to increased light extraction and internal quantum efficiency through near-field dipole-dipole coupling, thereby improving the overall performance of the diodes.
Implementation Method 1
radiative recombination of the electron-hole pairs in the active layer 13
Implementation Method 2
non-radiative coupling of dipole-dipole type between the emitting dipoles and the optical dipoles
Data Source
AI summary
The invention relates to a method for producing a light-emitting diode comprising a semiconductor stack formed of a first layer 11, of an active layer 13, and of an extraction layer 6. It comprises a step of determining a distance h1s between emitting dipoles μ1 that are located in the active layer 13 and the extraction layer 6, such that the emitting dipoles μ1 of vertical orientation have in particular a lifetime longer than that of the emitting dipoles of horizontal orientation.