Blue Light Emitting Elements With Wavelength Tuning for Reliability
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Solution Overview
Problem
The reliability of light emitting elements in display devices is compromised due to surface damage and decreased luminance, particularly when the size of the light emitting elements is reduced.
Innovation Solution
The reliability of light emitting elements is improved by increasing the emission wavelength, achieved by adjusting the indium content and thickness of the active layer, which minimizes surface damage and maintains luminance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the size of light emitting elements is reduced, then the pixel density and resolution are improved, but surface damage and reliability deteriorate
Solution Approach 1:
The patent applies parameter changes by adjusting the indium content (mole fraction 0.15-0.25) and thickness (1.0-2.8 nm) of the active layer to increase emission wavelength from 460nm to 468nm. This parameter optimization resolves the contradiction by maintaining reliability through improved material composition while enabling smaller element sizes for higher pixel density.
2Reliability
If the emission wavelength is increased, then the external quantum efficiency is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent resolves manufacturing complexity by optimizing parameters within standard fabrication capabilities: active layer thickness (1.0-2.8 nm) and indium mole fraction (0.15-0.25). These parameter changes achieve the desired 468nm emission wavelength and improved external quantum efficiency without requiring complex manufacturing processes, as they can be implemented through conventional molecular beam epitaxy with controlled growth conditions.
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 approach enhances the external quantum efficiency and maintains luminance over extended driving times, thereby improving the overall reliability of the light emitting elements.
Implementation Method 1
Each of the light emitting elements may emit light with a wavelength in a range of about 464 nm to about 468 nm at a current density in a range of about 0.5 A/cm2 to about 100 A/cm2
Data Source
AI summary
A display device includes a first electrode and a second electrode spaced apart from each other, and light emitting elements disposed between the first electrode and the second electrode. Each of the light emitting elements include a first semiconductor layer, a second semiconductor layer disposed on the first semiconductor layer, and an active layer disposed between the first semiconductor layer and the second semiconductor layer. Each of the light emitting elements emits light with a wavelength in a range of about 464 nm to about 468 nm at a current density in a range of about 0.5 A/cm2 to about 100 A/cm2, and has a maximum external quantum efficiency greater than or equal to about 15%.