μLED Display Element Structure for Higher Light Extraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing micro light emitting diode (μLED) display elements face challenges in achieving high light emission efficiency and reducing power consumption due to damage during processing, which results in low utilization of the compound semiconductor layer, especially when trying to miniaturize the μLEDs for full color displays.
Innovation Solution
The solution involves configuring micro light emitting elements with an excitation light emitting element, a reflective wall, and a wavelength conversion material, where the wavelength conversion material covers all surfaces except the bottom surface closer to the driving circuit substrate, and the reflective wall's sidewall is inclined to enhance light emission efficiency. The manufacturing process includes depositing a compound semiconductor layer, forming a separation trench, recovering damage, and carefully separating and polishing the semiconductor layer to reduce waste and improve efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the μLED size is decreased to increase light emission efficiency, then the light emission efficiency is improved, but the internal quantum efficiency is reduced due to processing damage
Solution Approach 1:
The patent applies preliminary action by performing damage recovery treatment on the compound semiconductor layer before completing the μLED fabrication process. Specifically, after forming the separation trench and before finalizing the device structure, the patent subjects the compound semiconductor layer to heat treatment or other recovery processes that repair processing-induced damage, thereby restoring carrier mobility and reducing non-radiative recombination centers before the device is fully assembled and tested
Solution Approach 2:
The patent converts the harmful effect of processing damage into a benefit by deliberately introducing controlled stress or damage during fabrication, then using subsequent heat treatment or annealing processes to transform this damage into improved crystalline structure. The processing damage initially created during trench formation or layer separation is converted into opportunities for stress relief and crystal rearrangement that enhance the overall device performance
2Productivity
If the μLED size is decreased for miniaturization, then the display resolution is improved, but the majority of the compound semiconductor layer is lost
Solution Approach 1:
The patent applies segmentation by dividing the compound semiconductor layer into multiple functional regions through the formation of separation trenches. Instead of using the entire layer for active devices, the patent segments the layer into active μLED regions and sacrificial regions that are removed during processing. This segmentation allows for more efficient use of the remaining material while achieving higher resolution displays
Solution Approach 2:
The patent transitions from two-dimensional planar structures to three-dimensional vertically stacked structures. By stacking multiple compound semiconductor layers vertically and forming μLEDs at different heights, the patent increases the effective utilization of semiconductor material while maintaining small footprint devices. This dimensional transition allows more material to be used productively in the vertical direction rather than being lost in lateral expansion
3Loss of energy
If the wavelength conversion material covers all surfaces of the μLED, then the wavelength conversion efficiency is increased, but the manufacturing complexity increases
Solution Approach 1:
The patent merges multiple functions into the wavelength conversion material layer. Instead of having separate layers for wavelength conversion, encapsulation, and protection, the patent combines these functions into a single integrated layer that performs wavelength conversion while simultaneously providing structural support and environmental protection. This merging reduces the number of fabrication steps and simplifies the overall manufacturing process
Solution Approach 2:
The wavelength conversion material is designed to serve multiple functions: it converts the excitation wavelength to the desired emission wavelength, acts as an encapsulation layer protecting the μLED from environmental degradation, provides mechanical support, and facilitates heat dissipation. This multi-functionality reduces the need for additional separate components and simplifies the overall device structure
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 significantly increases light emission efficiency and reduces power consumption, allowing for the effective use of the compound semiconductor layer, enabling the creation of high-efficiency, low-power full color displays with reduced manufacturing costs.
Implementation Method 1
a wavelength conversion material disposed inside the reflective wall, the wavelength conversion material absorbs the excitation light and emits light having a wavelength longer than a wavelength of the excitation light
Implementation Method 2
a reflective wall surrounding a periphery of the excitation light emitting element
Data Source
AI summary
An image display element includes micro light emitting elements disposed in an array on a driving circuit substrate. An excitation light emitting element includes a main body including a compound semiconductor, a metal electrode disposed on a side of the main body located closer to the driving circuit substrate, and a transparent electrode disposed on an opposite side to the driving circuit substrate, and a light emission layer included in the main body is disposed on a side opposite to the driving circuit substrate from a center portion of the main body.