Micro-Device Substrate Integration With Patterned Reflectors
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Solution Overview
Problem
The challenge lies in effectively integrating millions of micro-devices with circuits for each pixel while maintaining proper yield, particularly in achieving uniform light output and structural integrity in micro-device substrates.
Innovation Solution
The integration of micro-devices with circuits on a substrate involves the use of reflective layers, patterned for improved light output uniformity, and the use of transfer technologies like electrostatic and elastomer transfer heads, along with pad mechanisms, to connect micro-devices to integrated circuit layers, ensuring mechanical and electrical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If micro-devices are integrated onto a substrate with circuits, then system performance and integration density are improved, but manufacturing complexity and yield control deteriorate
Solution Approach 1:
The patent segments the integration process into distinct phases: micro-device fabrication on a donor substrate, pattern formation on both donor and receiver substrates, and controlled transfer operations. This segmentation allows each step to be optimized independently, managing the complexity of integrating millions of micro-devices while maintaining high integration density
Solution Approach 2:
The patent applies preliminary action by pre-forming patterns on both the donor substrate (where micro-devices will be transferred) and the receiver substrate (where circuits are located) before the actual transfer operation. This advance preparation ensures proper alignment and reduces manufacturing complexity during the critical transfer phase
2Productivity
If transfer technologies are used to move micro-devices, then integration efficiency is improved, but transfer precision and alignment control worsen
Solution Approach 1:
The patent introduces an intermediary transfer head that mediates between the donor substrate and receiver substrate. This transfer head serves as a controlled interface that can pick up micro-devices from the patterned donor substrate and place them on the patterned receiver substrate with precise alignment, thereby maintaining both high transfer efficiency and transfer precision
Solution Approach 2:
The patent replaces traditional mechanical pick-and-place systems with electrostatic transfer mechanisms. By using electrostatic fields to hold and transfer micro-devices, the system achieves higher precision and better control over the transfer process while maintaining efficient integration of millions of devices
3Illumination intensity
If reflective layers are added to improve light output, then optical performance is improved, but device structure and manufacturing complexity worsen
Solution Approach 1:
The patent applies local quality by implementing patterned reflective layers rather than uniform coverage. The reflective layers are strategically positioned in specific patterns to optimize light extraction and uniformity from micro-LEDs, providing improved optical performance only where needed while minimizing additional structural complexity
Solution Approach 2:
The patent merges the reflective layer function with the existing substrate and device structure. By integrating the reflective layers into the overall device architecture and combining multiple functions (structural support, light reflection, and electrical connection) into unified components, the patent improves light output while limiting the increase in manufacturing complexity
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 approach enables efficient and uniform integration of micro-devices with circuits, enhancing light output and structural integrity, thereby addressing the yield and uniformity challenges in micro-device substrates.
Implementation Method 1
pick and place with different mechanisms, e.g. electrostatic transfer head
Implementation Method 2
elastomer transfer head
Implementation Method 3
Light sources sandwiched between two reflective layers with at least one is a patterned reflective layer. The patterned reflective layer may have a profiled pattern to improve the light output uniformity
Data Source
AI summary
An integrated optical display system includes a backplane with appropriate electronics, and an array of micro-devices. A touch sensing structure may be integrated into the system. In one embodiment, an integrated circuit and system is integrated on top of micro-devices transferred to a substrate. Openings in a planarization layer (or layers) may be provided to connect the micro-devices with electrodes and other circuitry. Light reflectors may be used to redirect the light, and color conversion layers or color filters may be integrated before the micro-devices or on the substrate surface opposite to the surface of micro-devices.