Micro LED Array via Continuous Conversion Film
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Solution Overview
Problem
The manufacturing of micro light-emitting diode (μLED) arrays faces challenges in the massive transfer of micron-level epitaxial layers, leading to low yield and efficiency due to potential die damage and alignment issues, resulting in defects and reduced illumination efficiency.
Innovation Solution
The use of continuous conversion films without grain boundaries, formed by dissolving light-emitting materials and a host in a solvent, which absorb and re-emit light, eliminating grain boundaries and light scattering, and can be patterned to define pixels as small as 10 μm, eliminating the need for massive transfer and improving yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional mass transfer methods are used to place epitaxial layers on target substrate, then alignment precision can be achieved, but manufacturing time and complexity increase significantly due to repeated transfers
Solution Approach 1:
The patent merges multiple separate transfer operations into a single batch transfer process. By arranging multiple epitaxial layers on a common transfer substrate and transferring them simultaneously to the target substrate, the method eliminates repeated transfer cycles, reducing manufacturing time while maintaining alignment precision through the unified transfer process.
Solution Approach 2:
The patent applies preliminary action by pre-arranging multiple epitaxial layers on a transfer substrate before the transfer process. The epitaxial layers are positioned and prepared in advance on the transfer substrate, allowing for batch transfer to the target substrate, thereby reducing the number of repeated transfer operations required.
2Quantity of substance
If conventional mass transfer methods are used to place epitaxial layers on target substrate, then coverage can be achieved, but yield decreases due to die damage and alignment issues
Solution Approach 1:
The patent merges multiple epitaxial layer transfers into a single batch operation. By transferring multiple layers simultaneously in one process step, the method reduces the cumulative probability of die damage and alignment errors that occur with repeated transfers, thereby improving overall yield while achieving complete substrate coverage.
Solution Approach 2:
The patent applies beforehand cushioning by using a transfer substrate as an intermediate carrier that protects epitaxial layers during handling and transfer. The transfer substrate provides mechanical support and protection, reducing the risk of die damage during the transfer process and improving the reliability of the final product.
3Use of energy by moving object
If conventional fluorescent films with grain boundaries are used, then light conversion can be achieved, but illumination efficiency decreases due to light scattering
Solution Approach 1:
The patent applies parameter changes by transitioning from conventional fluorescent films with grain boundaries to a grain-boundary-free fluorescent layer. This structural parameter change eliminates light scattering at grain boundaries, reducing energy loss and improving illumination efficiency while maintaining the light conversion function.
Solution Approach 2:
The patent uses composite materials by combining the fluorescent material with a host matrix to form a uniform fluorescent layer without grain boundaries. This composite structure maintains the light conversion properties of the fluorescent material while eliminating the detrimental effects of grain boundaries on illumination efficiency.
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 method significantly enhances the yield and brightness of μLEDs, reduces manufacturing time, and allows for more precise pixel definition, outperforming OLEDs in brightness and driving power, while eliminating the need for high-precision mass transfer.
Implementation Method 1
Each light-emitting material absorbs the first light and then re-emitting another light with a color different from the first color
Implementation Method 2
The host eliminates grain boundaries and light scattering of the one or more light-emitting materials
Data Source
AI summary
An embodiment of the present invention provides a micro light emitting diode (LED) array and its manufacturing method. The micro-LED includes a substrate, an epitaxial layer formed on the substrate, and a conversion film formed on the epitaxial layer. Pixels can be defined through lithography, and the pixel size can be very small. This method is characterized in that a mass transfer is not required.