Vertically Stacked Micro Display Pixels for Sub-10 μm Efficiency
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Solution Overview
Problem
Micro LED display technology faces challenges with horizontal pixel unit arrangements, where the proportion of active area to total pixel area is limited, leading to reduced external quantum efficiency, especially as the size decreases below 10 μm, affecting luminous area and efficiency.
Innovation Solution
A pixel unit with vertically stacked device layers and a common cathode connected to each layer, reducing the cathode area ratio and increasing the luminous area ratio, while also allowing for redundant circuit formation and optical enhancement structures to prevent optical crosstalk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If horizontal pixel unit arrangement is used, then device complexity is reduced, but active area ratio decreases and external quantum efficiency drops
Solution Approach 1:
The patent transitions from horizontal arrangement to vertical stacking of device layers, changing the spatial dimension from 2D to 3D. This vertical stacking allows multiple luminous bodies of different colors to be stacked along the vertical direction, increasing the active area ratio and external quantum efficiency while maintaining manageable device complexity through systematic layer design.
2Productivity
If active area size is reduced below 10 μm, then pixel density increases, but external quantum efficiency drops sharply
Solution Approach 1:
By stacking multiple device layers vertically, the patent increases the effective luminous area without increasing the horizontal pixel footprint. This allows smaller pixel pitch (higher pixel density) while maintaining adequate active area through the vertical dimension, preventing the sharp EQE drop that occurs with sub-10 μm horizontal reduction.
Solution Approach 2:
The patent combines multiple luminous bodies of different colors (red, green, blue) into a single vertical stack within one pixel unit. This merging approach increases the effective luminous area ratio within the pixel while maintaining high pixel density, as all color elements share the same horizontal footprint but are distributed vertically.
3Reliability
If vertically stacked device layers are implemented, then active area ratio increases, but device complexity increases
Solution Approach 1:
The patent segments the pixel unit into distinct device layers, with each layer containing a specific color luminous body (red, green, or blue). This segmentation allows independent design and optimization of each layer while maintaining overall system functionality, managing complexity through modular layer structure.
Solution Approach 2:
Each device layer is designed with universal structural elements (substrate, electrode, encapsulation) that can be replicated across different color layers. This universality reduces overall device complexity by using standardized components while achieving high active area ratio through the multi-layer vertical configuration.
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 vertical stacking approach enhances the active area ratio, reduces size effects, and improves quantum efficiency, enabling more efficient multi-color display with increased pixel density and reduced space occupation.
Implementation Method 1
Micro LED display technology refers to a display technology that uses self-luminous micron dimension LEDs as luminous pixel units
Data Source
AI summary
This application discloses a pixel unit for semiconductor device and a manufacturing method, a micro display screen, and a discrete device, the pixel unit includes a target drive circuit, a display unit, and a common cathode, the backplane is provided with a drive circuit, and the drive circuit is provided with at least one anode; the display unit is provided on the backplane, it includes a first device layer and a second device layer stacked vertically from bottom to top, the first device layer and the second device layer are respectively connected to the corresponding anodes of the backplane; the common cathode is respectively connected to each device layer in the display unit, and the common cathode is connected to the external cathode.