Micro LED Active Layer Structure for Surface Damage Reliability
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Solution Overview
Problem
Current display devices face reliability issues due to surface damage of light emitting elements, leading to luminance deterioration, particularly when the size of these elements is in the nanometer to micrometer scale.
Innovation Solution
The display device incorporates light emitting elements with a specific structure, including a first and second semiconductor layer and an active layer with a thickness of 1 nm to 2.8 nm, made of InGa1-xN (0.18≤x≤0.20), which emits light in the 462 nm to 472 nm wavelength range, and is surrounded by an insulative film to prevent electrical shorts and surface defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the light emitting element size is reduced to nanometer to micrometer scale, then the display device can achieve higher resolution and smaller pixel size, but surface damage occurs leading to luminance deterioration and reliability issues
Solution Approach 1:
The patent applies this principle by introducing an insulative film that surrounds the light emitting element. This thin film layer protects the nanoscale light emitting element from surface damage while maintaining its small size, thus resolving the contradiction between miniaturization and reliability.
Solution Approach 2:
The patent implements prior cushioning by pre-establishing protective structures (insulative film and specific semiconductor layer configurations) before the light emitting element operates. This preventive approach shields the element from surface damage that would otherwise occur at nanoscale dimensions.
2Loss of energy
If the active layer thickness is reduced to 1 nm to 2.8 nm, then the light emission efficiency is improved, but the element becomes more susceptible to surface damage and manufacturing defects
Solution Approach 1:
The insulative film surrounding the active layer provides protection against surface damage while maintaining the thin active layer configuration that ensures high light emission efficiency. This resolves the contradiction between efficiency and reliability.
Solution Approach 2:
The patent uses composite material structures with specific semiconductor layers having different compositions (InGa1-xN with controlled x values) to create a multi-layer system where each layer contributes to both efficiency and protection, resolving the trade-off between thin layer performance and durability.
3Illumination intensity
If the indium composition (x value) is increased to 0.20, then the light wavelength shifts to the desired 462-472 nm range, but the manufacturing precision requirements increase
Solution Approach 1:
The patent systematically varies the indium composition parameter (x value from 0.18 to 0.20) to achieve the target light wavelength range. By establishing specific parameter ranges rather than fixed values, the patent balances wavelength control with manufacturability, reducing the stringency of precision requirements while maintaining performance.
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 enhances the reliability and luminance of the light emitting elements by minimizing surface damage and improving light emission efficiency, while allowing for precise control of indium composition and thickness to optimize performance.
Implementation Method 1
The active layer may include InGa1-xN (about 0.18≤x≤about 0.20). The light emitting elements may emit light with a wavelength in a range of about 462 nm to about 472 nm in 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 includes 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. A thickness of the active layer is in a range of about 1 nm to about 2.8 nm, the active layer includes InGa1-xN (about 0.18≤x≤about 0.20). The light emitting elements emit light with a wavelength in a range of about 462 nm to about 472 nm in a current density in a range of about 0.5 A/cm2 to about 100 A/cm2.