Thin Film Optocoupled Active Matrix Backplane for High Voltage Isolation
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Solution Overview
Problem
Existing active matrix arrays are inadequate for high voltage applications, particularly in high density displays and MEMS devices, due to the need for effective electrical isolation between control and output circuits.
Innovation Solution
The development of an optocoupled active matrix backplane with thin film solid state optical switches, where pixelated light sources control the switches to isolate high voltage nodes from low voltage control systems, enabling high density arrays with scalable pixel configurations and multiple voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional electrical isolation methods are used between control and output circuits, then electrical isolation is achieved, but device complexity and size increase
Solution Approach 1:
The patent replaces traditional electrical isolation methods (mechanical/electrical components) with optical coupling. Optical switches convert electrical control signals to optical signals that pass through an insulating barrier, then convert back to electrical signals on the output side, achieving isolation without complex electrical isolation components.
Solution Approach 2:
The patent introduces optical signals as an intermediary between the low-voltage control circuit and high-voltage output circuit. The optical signal serves as a mediator that transfers control information across the electrical isolation barrier without direct electrical connection, simplifying the isolation architecture.
2Quantity of substance
If high density arrays are implemented, then pixel density increases, but manufacturing precision requirements worsen
Solution Approach 1:
The patent divides the array into independently addressable rows and columns with clear scanning sequences. Each pixel is segmented with defined row/column indices, allowing precise addressing and control even at high densities. The segmentation into addressable units simplifies the control architecture and reduces alignment requirements.
Solution Approach 2:
The patent uses a two-dimensional address space (row, column) to uniquely identify each pixel, adding spatial dimensionality to the addressing scheme. This dimensional approach allows efficient addressing of high-density arrays without requiring excessive precision in physical positioning, as logical addressing compensates for physical variations.
3Adaptability or versatility
If multiple voltage levels are supported, then application versatility improves, but device complexity increases
Solution Approach 1:
The patent implements dynamic voltage level selection where the output voltage level is determined by the control signal parameters rather than fixed circuit configurations. The system can dynamically switch between different voltage levels (e.g., ±100V, ±50V, or lower) by adjusting the control signals, providing versatility without requiring multiple dedicated circuits for each voltage level.
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 solution provides efficient high voltage output isolation, enabling applications such as MEMS devices and optical mirror arrays with high resolution and reduced leakage currents, suitable for high frequency and multi-level voltage requirements.
Implementation Method 1
Each optical switch includes a layer of photo sensitive material that extends laterally; first and second electrodes spaced apart laterally from one another along the layer of photo sensitive material
Data Source
AI summary
A device includes a backplane having multiple output terminals arranged in an array on an output surface of the backplane. The device further includes an active matrix array comprising thin film solid state optical switches coupled respectively between an input terminal of the backplane and the output terminals. Storage capacitors may be coupled respectively to the output terminals. A pixelated light source provides pixelated light that controls the optical switches.