Back Gate Line Driving for Feedthrough-Stable Array Substrates
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Solution Overview
Problem
Existing display devices, such as liquid crystal and organic EL displays, face challenges in achieving high definition and high opening ratio due to parasitic capacitance issues that cause feedthrough and flicker, particularly when using AC voltage driving methods.
Innovation Solution
The implementation of a display device configuration that includes a back gate circuit generating a reverse polarity voltage, applied via a back gate line parallel to the gate line, which cancels feedthrough by adjusting the back gate voltage at specific timing, thereby maintaining image stability and improving display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If AC voltage driving is performed by frame inversion method, then liquid crystal panel life is extended, but feedthrough occurs causing image flicker and degraded display quality
Solution Approach 1:
The patent applies preliminary anti-action by introducing a back gate voltage with reverse polarity before the feedthrough effect can occur. The back gate voltage is applied in advance during the TFT on-period to counteract the voltage shift caused by parasitic capacitance, thereby preventing feedthrough and image flicker while maintaining AC voltage driving benefits
Solution Approach 2:
The patent converts the harmful parasitic capacitance effect into a beneficial one by utilizing the back gate voltage to generate an opposing electric field. The parasitic capacitance between gate electrode and source/drain electrodes, which normally causes feedthrough, is counteracted by the deliberately introduced back gate voltage, transforming the problem into a solution
2Measurement precision
If opening ratio is increased for high definition display, then resolution is improved, but parasitic capacitance effects are exacerbated causing more severe feedthrough
Solution Approach 1:
The back gate voltage is applied in advance during the TFT on-period to counteract voltage shifts before they occur. This preliminary anti-action effectively suppresses feedthrough even in high opening ratio designs where parasitic capacitance effects are more pronounced, enabling high definition display without sacrificing image quality
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 effectively prevents feedthrough and enhances display quality by maintaining image stability and increasing the opening ratio, allowing for higher resolution and reduced flicker in display devices.
Implementation Method 1
the parasitic capacitance occurred between a gate electrode and a source electrode or between the gate electrode and a drain electrode of the TFT causes a feedthrough in which the level of the voltage applied to the pixel electrode is shifted
Data Source
AI summary
A display device includes a display unit including a plurality of pixels, a first drive circuit supplying a gate voltage to drive the plurality of pixels, a gate line connected to the plurality of pixels and the first drive circuit, the gate line transmitting the gate voltage to the plurality of pixels, a second drive circuit supplying a drive voltage corresponding to a luminance of each of the plurality of pixels, a data line connected to the plurality of pixels and the second drive circuit, the data line transmitting the drive voltage to the plurality of pixels, a back gate circuit generating a back gate voltage having a reverse polarity of the gate voltage, and a back gate line extending parallel to the gate line, the back gate line transmitting the back gate voltage to the plurality of pixels.