Micro LED Insulating Film Structure for Afterimage Reduction
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Solution Overview
Problem
Display devices using light emitting elements suffer from afterimages and response delays due to surface defects and defects in semiconductor layers, particularly in small diameter elements.
Innovation Solution
A light emitting element with a specific structure including a first semiconductor layer doped with an n-type dopant, a second semiconductor layer doped with a p-type dopant, an active layer, and an insulating film with multiple layers such as AlN, ZrO2, and Al2O3, which minimizes surface defects through a sol-gel process, ensuring rapid luminance changes and reduced afterimages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the diameter of the light emitting element is reduced to achieve higher pixel density, then the display resolution is improved, but surface defects and semiconductor layer defects increase causing afterimages and response delays
Solution Approach 1:
The patent applies local quality by creating a multi-layer insulating film structure with different materials (silicon oxide, silicon nitride, aluminium nitride) and thicknesses at different locations. The first insulating film has a first layer and second layer with different compositions, and the second insulating film has a third layer and fourth layer, where each layer is optimized for specific local requirements of the small diameter light emitting element structure to prevent defects and reduce afterimages
Solution Approach 2:
The patent uses composite materials by combining multiple insulating film layers made of different materials (silicon oxide, silicon nitride, aluminium nitride) with varying thicknesses. This composite structure provides enhanced protection against surface defects and semiconductor layer defects while maintaining the small diameter of the light emitting element, thereby reducing afterimages and improving response time
2Device complexity
If a simple insulating film structure is used to reduce manufacturing complexity, then the device complexity is reduced, but surface defects are not adequately minimized leading to afterimages
Solution Approach 1:
The patent applies segmentation by dividing the insulating film into multiple distinct layers: a first insulating film with a first layer and second layer, and a second insulating film with a third layer and fourth layer. Each layer serves specific functions in minimizing surface defects, and this segmented structure is particularly effective for small diameter light emitting elements to prevent afterimages while maintaining manufacturability
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 solution reduces afterimages and response delays by minimizing surface defects, allowing for rapid luminance adjustments and improved electrical and optical characteristics, even in small diameter elements.
Implementation Method 1
an insulating film with multiple layers such as AlN, ZrO2, and Al2O3, which minimizes surface defects through a sol-gel process
Implementation Method 2
a light emitting element having reduced afterimages when emitting light
Data Source
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AI summary
A light emitting element includes a first semiconductor layer doped with an n-type dopant, a second semiconductor layer disposed on the first semiconductor layer and doped with a p-type dopant, an active layer between the first semiconductor layer and the second semiconductor layer, an electrode layer disposed on the second semiconductor layer, and an insulating film surrounding an outer surface of at least the active layer. A diameter of the first semiconductor layer is in a range of about 0.5 µm to about 10 µm, and the insulating film includes a first layer surrounding the first semiconductor layer, the second semiconductor layer, and the active layer and a second layer disposed on the first layer and including aluminium nitride (AlN).