LED Dipole Orientation via Reflective Electrode Distance

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Solution Overview

Problem

Existing light-emitting diodes (LEDs) do not achieve optimal luminous efficacy due to limitations in the orientation and positioning of emitting dipoles relative to reflective electrodes and surrounding media, which affects the lifetime and orientation of these dipoles.

Innovation Solution

A method for producing LEDs by strategically choosing the orientation of emitting dipoles and determining specific distances between these dipoles and reflective electrodes and surrounding media, based on predetermined functions that account for the optical properties of materials, to maximize the lifetime and orientation of emitting dipoles, thereby enhancing luminous efficacy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the distance between the active layer and reflective layer is determined to achieve horizontal orientation of emitting dipoles, then luminous efficacy is improved, but the lifetime of emitting dipoles with chosen orientation becomes shorter compared to vertical orientation

Engineering Contradiction:

Improveluminous efficacyVSAvoidlifetime of emitting dipoles

Core Design Contradiction:

Loss of energyVSDuration of action of moving object

Solution Approach 1:

The patent changes the distance parameter between the active layer and reflective electrode to optimize the orientation of emitting dipoles. By adjusting this distance, the patent achieves a balance between improving luminous efficacy through horizontal dipole orientation and maintaining acceptable dipole lifetime, resolving the technical contradiction between energy efficiency and component durability.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If emitting dipoles are oriented horizontally to improve luminous efficacy, then light extraction efficiency increases, but the lifetime of horizontally oriented dipoles is shorter than vertically oriented dipoles

Engineering Contradiction:

Improvelight extraction efficiencyVSAvoidlifetime of emitting dipoles

Core Design Contradiction:

ProductivityVSDuration of action of moving object

Solution Approach 1:

The patent modifies the distance parameter between the active layer and reflective electrode to control dipole orientation. This parameter change enables horizontal dipole orientation that enhances light extraction efficiency while accepting the trade-off of reduced dipole lifetime, thereby resolving the contradiction between productivity and duration of action.

Inventive Principle:

Principle #35Parameter changes

3Loss of energy

If the distance between emitting dipoles and reflective electrode is reduced to achieve horizontal orientation, then luminous efficacy improves, but manufacturing precision requirements increase

Engineering Contradiction:

Improveluminous efficacyVSAvoiddistance control precision

Core Design Contradiction:

Loss of energyVSManufacturing precision

Solution Approach 1:

The patent determines a specific distance value between the active layer and reflective electrode that optimizes luminous efficacy through horizontal dipole orientation. This precise parameter determination addresses the manufacturing precision challenge by establishing a target distance that balances performance improvement with manufacturability.

Inventive Principle:

Principle #35Parameter changes

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 improves the luminous efficacy of LEDs by optimizing the orientation and positioning of emitting dipoles, leading to increased radiative recombination and light extraction efficiency, resulting in enhanced external quantum efficiency.

Implementation Method 1

a reflective electrode 4 forming the anode... The reflective electrode 4 is preferably made of a metal material

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 2

The charge carriers (electrons and holes) are introduced into the semiconductor stack by the electrodes 4, 5, then diffuse to the active layer 13 where they recombine radiatively. The luminous radiation associated with the radiative recombination of the electron-hole pairs in the active layer 13

Methodology Applied

Scientific EffectRadiative recombination: Electroluminescence

Data Source

PatentUS11430972B2Method for producing a light-emitting diode comprising a step of dimensioning a semiconductor layer

Publication Date: 2022.08.30 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES

AI summary

The invention relates to a method for producing a light-emitting diode, comprising a stack formed of a first semiconductor layer 11 and of an active layer 13, a reflective electrode 4 extending in contact with the first semiconductor layer 11, comprising a step of determining a distance between emitting dipoles that are located in the active layer 13 and the reflective electrode 4 for which a lifetime of the emitting dipoles having a chosen orientation is longer than that of the emitting dipoles having the non-chosen orientation.