Electro-Optical Matrix Addressing for High-Frequency Pixel Control
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Solution Overview
Problem
Existing active-matrix systems for controlling functional devices on substrates face limitations due to signal degradation from resistive losses and parasitic capacitance, which restrict control signal frequencies and increase operational sensitivity to voltage variations.
Innovation Solution
An electro-optically controlled active-matrix system is introduced, featuring row wires and column light-pipes with a row controller providing electrical signals and a column controller providing optical signals, respectively, allowing pixels to receive both signals for improved control and reducing the need for physical electrical connections through capacitive coupling and micro-transfer printing of inorganic light-emitting diodes and sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If electrical signals are transmitted through row and column wires extending over large substrates, then functional devices can be controlled in a matrix-addressed array, but signal degradation occurs due to wire resistance, propagation delays, and parasitic capacitance that limit control signal frequencies
Solution Approach 1:
The patent segments the control signal transmission by dividing the matrix-addressed array into regions served by different light-pipe sources. Instead of using a single continuous electrical wiring system across the entire substrate, multiple independent light-pipe sources transmit optical signals to different regions, eliminating the cumulative resistance and parasitic capacitance effects that would occur in long electrical wires spanning the full substrate area.
Solution Approach 2:
The patent replaces the electrical signal transmission system with an optical signal transmission system using light-pipes. Optical signals do not suffer from resistance, inductance, or parasitic capacitance effects that limit electrical signal frequencies. This substitution of transmission medium fundamentally resolves the signal degradation problem while maintaining matrix-addressing capability through the coordinated operation of row and column light-pipes.
2Use of energy by stationary object
If electrical signals are transmitted through power and ground wires across large substrates, then functional devices can be powered, but voltage values differ at different locations due to resistance in power and ground wires
Solution Approach 1:
The patent replaces electrical power and ground distribution wires with optical signal transmission through light-pipes. Optical signals carry information without requiring return paths and do not suffer from voltage drops due to resistance. This eliminates the voltage non-uniformity problem across the substrate while still enabling control of functional devices through optical modulation that encodes control information.
3Reliability
If individually packaged integrated-circuit devices are assembled on the substrate using pick-and-place tools, then transistors with higher performance can be achieved, but the packages are larger than desired for highly integrated systems
Solution Approach 1:
The patent uses light-pipes as optical copies or waveguides that transmit control signals without requiring physical electrical connections to each functional device. The light-pipes carry optical signals that can be modulated to address specific functional devices in the matrix array, eliminating the need for large packaged IC devices while maintaining control capability through optical field effects rather than direct electrical connections.
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 enhances the frequency of pixel operation and reduces sensitivity to supply voltage variations, improving signal integrity and reducing resistive losses across the substrate.
Implementation Method 1
a column controller operable to provide a respective column optical signal to each of the column light-pipes
Implementation Method 2
Electrical signal communication can be through capacitive coupling, for example as disclosed in U.S. Pat. No. 6,854,030
Data Source
AI summary
An electro-optically controlled active-matrix system comprises a system substrate, row wires extending in a row direction disposed on the system substrate, a row controller providing a row electrical signal to each row wire, column light-pipes extending in a column direction disposed on the system substrate, a column controller providing a column optical signal to each column light-pipe, and pixels disposed over the system substrate. Each pixel can comprise a pixel circuit that is uniquely responsive to a row wire and to a column light-pipe, the pixel circuit receiving the row electrical signal from the row wire and receiving the column optical signal from the column light-pipe. In some embodiments, column wires carrying column electrical signals extend in a column direction over the system substrate and the pixel circuit is capacitively coupled to the row wire, the column wire, or both.