Silicon CMOS LED Pixel Backplane for Fast Uniform Microdisplays
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Solution Overview
Problem
Traditional Low-Temperature Polysilicon (LTPS) Thin-Film Transistor (TFT) backplanes in active-matrix LED displays face limitations such as low electron mobility, slow switching speeds, power inefficiency, and reliability issues, making them unsuitable for high-resolution and small pixel displays.
Innovation Solution
A light-emitting device with components fabricated on a silicon substrate, utilizing CMOS technology for improved electron mobility, incorporating a control circuit on the silicon substrate to manage power and data signals, and employing wafer-level processing for parallel fabrication of power supply pads, driving pads, data pads, pixels, and LEDs, enabling active matrix addressing and precise brightness control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If traditional LTPS TFT backplanes are used to control individual pixels, then the display can be manufactured with existing technology, but the electron mobility is relatively low resulting in insufficient driving power for bright or small LEDs
Solution Approach 1:
The patent changes the fundamental material parameter from LTPS (low-temperature polysilicon) to silicon-based technology, which provides inherently higher electron mobility. This parameter change enables sufficient driving power for bright and small LEDs while maintaining performance consistency across the display panel.
2Measurement precision
If traditional LTPS backplanes with complicated PWM control circuits are used, then precise brightness control can be achieved, but the switching speed becomes slow
Solution Approach 1:
The patent changes the transistor material parameter from LTPS to silicon-based technology, which provides higher electron mobility and faster switching speeds. This enables precise brightness control to be achieved with simpler circuits and faster response times, eliminating the need for complicated PWM control circuits.
3Ease of manufacture
If LTPS material with many small crystals is used, then the backplane can be manufactured, but significant variations in threshold voltage occur across the display panel resulting in uneven brightness and color
Solution Approach 1:
The patent changes the material structure parameter from polycrystalline (many small crystals) to monocrystalline silicon-based material. This structural change eliminates grain boundaries and crystal orientation variations, resulting in uniform threshold voltage across the entire display panel and consistent brightness and color performance.
4Productivity
If traditional LTPS backplane technology is used, then existing manufacturing processes can be utilized, but scaling up production for very dense micro LED arrays encounters challenges
Solution Approach 1:
The patent changes the material parameter from LTPS to silicon-based technology, which provides higher electron mobility and better electrical characteristics. This enables the backplane to support very dense micro LED arrays with sufficient driving power while maintaining long-term durability and reliability under high current conditions.
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
The silicon-based solution provides faster response times, better power efficiency, uniform brightness, and scalability, resulting in high-quality displays with precise color accuracy and reduced manufacturing costs.
Implementation Method 1
The LEDs are formed on the silicon substrate
Data Source
AI summary
A light-emitting device has power supply pads, driving pads, data pads, and pixels, all fabricated on a silicon substrate. Each pixel has power, driving, and data terminals that connect to the corresponding pads to receive power, driving, and data signals, respectively. Each pixel further includes light-emitting diodes (LEDs) and a control circuit. The control circuit, integrated within each pixel on the silicon substrate, regulates the operation of the LEDs in that pixel based on the received driving and data signals, thereby enabling individual pixel-level control within the device.