Stacked OLED on SOI Substrate with Intermediate Control Node
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional OLED display technology using bulk silicon substrates is limited to conveying only positive voltage, preventing the reverse driving of OLEDs and limiting pixel dimension reduction and resolution enhancement.
Innovation Solution
A stacked, non-inverted, dielectrically isolated OLED display utilizing a silicon-on-insulator (SOI) based active matrix backplane, allowing both positive and negative voltage application through vias connected to a common intermediate control node, enabling independent actuation of diodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional bulk silicon substrate is used, then manufacturing process is simple, but voltage can only be conveyed in positive direction and reverse driving is prevented
Solution Approach 1:
The substrate is segmented into multiple functional layers: a silicon layer for transistor fabrication and a separate insulating layer (such as silicon dioxide or silicon nitride) positioned between the silicon and the OLED stack. This segmentation allows the silicon transistors to control voltage while the insulating layer enables bidirectional voltage conveyance by preventing charge accumulation at the substrate interface, thus resolving the contradiction between manufacturing simplicity and voltage adaptability.
Solution Approach 2:
An insulating layer is introduced as an intermediary between the conventional silicon substrate and the OLED stack. This intermediary layer acts as a buffer that allows positive and negative voltages to be conveyed through the bulk without interfering with the silicon transistor operation, enabling reverse driving capability while maintaining compatibility with existing silicon manufacturing processes.
2Adaptability or versatility
If conventional silicon technology with common substrate potential is used, then transistor isolation is achieved, but negative voltage application forward biases junctions and renders transistors inoperative
Solution Approach 1:
The insulating layer serves as a mediator that decouples the voltage reference potential from the substrate. By placing the insulating layer between the silicon substrate and the OLED stack, negative voltages can be applied to the OLED without forward-biasing the silicon junctions, as the insulating layer isolates the electrical reference. This maintains transistor reliability while enabling negative voltage operation.
Solution Approach 2:
The solution moves the voltage reference from the substrate plane to an intermediate insulating layer plane. This dimensional shift in voltage reference allows independent control of substrate potential and OLED stack potential, enabling negative voltage application without affecting transistor junction biasing conditions.
3Adaptability or versatility
If stacked OLED architecture with vias is implemented, then independent diode actuation with bidirectional voltage is enabled, but device structure becomes more complex
Solution Approach 1:
The OLED display is segmented into multiple stacked OLED units, each with its own anode and cathode, separated by intermediate control electrodes. Vias are used to provide vertical electrical connections between these stacked units and the underlying silicon transistor layer. This segmentation allows independent voltage control of each OLED unit through the common substrate, enabling independent diode actuation while sharing common manufacturing infrastructure.
Solution Approach 2:
The silicon substrate with insulating layer serves as a universal platform that can control multiple stacked OLED units simultaneously. The same substrate and transistor fabrication process can address multiple OLED stacks, providing independent control through vias while maintaining manufacturing efficiency. This multi-functionality reduces the complexity increase that would result from completely separate control structures for each OLED unit.
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
Enables the independent actuation of OLEDs with both positive and negative voltages, overcoming the limitations of conventional silicon technology and enhancing pixel dimensions and resolution.
Implementation Method 1
the silicon junction is above the electrical insulator
Implementation Method 2
The light-emitting layer may be selected from any of a multitude of fluorescent and phosphorescent organic solids
Data Source
AI summary
A display and method of making a display, comprising first and second stacked, non-inverted, dielectrically isolated, organic light emitting diodes formed on a silicon on insulator substrate. The display includes a means for applying both a positive or negative voltage across the stack, and a common intermediate control node situated between the diodes. The control node is electrically connected through vias to receive a control voltage signal, such that altering the relationship between the control voltage signal and the voltage applied across the stack regulates the actuation of the individual diodes.