Amorphous Silicon Gate Driver Discharge Control
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Solution Overview
Problem
Flat panel displays using amorphous silicon manufacturing processes face issues with residual images due to the inability to effectively discharge pixel electrodes when turned off, as the off-controlling signal cannot be received by the shift registers, leading to prolonged charge retention in liquid crystal capacitors.
Innovation Solution
The implementation of a gate driving device with multiplexers and shift registers that receive and output specific voltage and clock signals in response to an off-controlling signal, allowing for the discharge of pixel electrodes by activating transistors on a glass substrate, ensuring complete discharge and eliminating residual images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an amorphous silicon gate driving device is used, then the display can be manufactured on a glass substrate, but the shift registers cannot receive the off-controlling signal to discharge pixel electrodes
Solution Approach 1:
The patent changes the voltage level parameter of the off-controlling signal from low-level (conventional) to high-level (compatible with amorphous silicon threshold voltages). By adjusting the signal parameter to match the amorphous silicon transistor characteristics, the shift registers can now receive and respond to the off-controlling signal, enabling pixel electrode discharge while maintaining amorphous silicon manufacturing compatibility.
2Ease of operation
If conventional low-level off-controlling signal is used, then the signal can be received by shift registers, but pixel electrodes cannot be discharged when display is turned off
Solution Approach 1:
The patent transforms the off-controlling signal from a low-level voltage signal to a high-level voltage signal. This parameter change enables the signal to exceed the threshold voltage of amorphous silicon transistors in the shift registers, allowing the signal to be properly received and executed, thereby restoring the pixel electrode discharge function when the display is turned off.
3Area of stationary object
If amorphous silicon manufacturing process is used, then large area deposition on glass substrate is achieved, but the discharging speed of pixel electrodes becomes too slow
Solution Approach 1:
The patent addresses the slow discharging speed by changing the voltage parameter of the off-controlling signal to a high level that can fully activate the amorphous silicon transistors. This ensures rapid charge discharge through the pixel electrodes, compensating for the inherently slower characteristics of amorphous silicon compared to monocrystalline silicon, while maintaining the advantage of large-area deposition on glass substrates.
Data Source
AI summary
A flat panel display includes pixel electrodes, multiplexers and a gate driver. The gate driver has an amorphous silicon gate structure and includes a displacement temporary storage unit having a plurality of shift registers each with a power supply source and a clock terminal. One of a first voltage and a second voltage is selected and transmitted to the power supply source, and one of the first voltage and a clock signal is selected and transmitted to the clock terminal according to an off-controlling signal for causing the pixel electrodes connected to the shift registers to discharge.