Lateral Gate Electrode TFT Switch for Liquid Crystal Display
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Solution Overview
Problem
Conventional TFT switches face challenges in simultaneously increasing charging capacity and aperture ratio, with existing methods either sacrificing aperture ratio or complicating the manufacturing process.
Innovation Solution
A lateral gate electrode TFT switch design featuring a substrate with vertically disposed source and drain electrodes, a semiconductor layer between them, and a gate electrode separated by a gate insulation layer, allowing for increased charging capacity and reduced volume while maintaining or improving aperture ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If large sized TFTs with larger W/L ratio are manufactured to raise charging capacity, then charging capacity is improved, but aperture ratio is sacrificed
Solution Approach 1:
The patent transitions from conventional planar TFT architecture to a 3D vertical stacked architecture. The gate electrode is folded back underneath the source and drain electrodes, creating a multi-layer structure where the gate wraps around the channel region. This dimensional change allows the gate to control a larger effective channel area without increasing the planar footprint, thereby increasing charging capacity while maintaining aperture ratio.
2Quantity of substance
If higher mobility technology such as LTPS or IGZO is selected to raise charging capacity, then charging capacity is improved, but manufacturing process becomes complicated and manufacturing defect-rate is increased
Solution Approach 1:
The patent changes the architectural parameters of the TFT rather than changing the semiconductor material parameters. Instead of adopting complex high-mobility materials like LTPS or IGZO, the invention achieves enhanced charging capacity through geometric parameter optimization - specifically the folded gate configuration that increases the effective gate-channel interaction area. This allows continued use of simpler a-Si materials while achieving improved performance.
3Area of stationary object
If TFT switches are downsized to increase aperture ratio, then aperture ratio is improved, but charging capacity needs to be increased with following
Solution Approach 1:
The folded gate structure enables the TFT to be downsized in planar dimensions while compensating for reduced charging capacity through vertical stacking. The gate electrode extends underneath the source and drain, effectively increasing the gate-controlled channel area in the vertical dimension. This allows smaller pixel layouts with higher aperture ratios while maintaining sufficient charging capacity through the enhanced 3D gate configuration.
Data Source
AI summary
A lateral gate electrode TFT switch and a liquid crystal display device are disclosed. The lateral TFT switch has a substrate, a source-drain area, a gate insulation layer and a gate electrode. The source-drain area is disposed on the substrate and has a source electrode, a drain electrode and a semiconductor layer. The semiconductor layer is disposed between the source electrode and the drain electrode. The source electrode and the drain electrode are vertically disposed on the substrate. The gate insulation layer is disposed adjacent to the source-drain area. The gate electrode is disposed adjacent to the gate insulation layer. The gate insulation layer is used to separate the source-drain area from the gate electrode.