Demultiplexer Coupling Capacitance Mitigates Feedthrough
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Solution Overview
Problem
The 1:K DEMUX circuit suffers from uneven display due to feedthrough effects caused by parasitic capacitance, leading to brightness differences between pixel units controlled by different data lines, which complicates achieving narrow bezels and power savings.
Innovation Solution
A demultiplexer design with N output channels connected to (K−1) data lines through switching transistors and directly to another data line, incorporating metal electrode plates to form coupling capacitance, allowing controlled potential changes to mitigate feedthrough effects and ensure uniform brightness across all data lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If each output channel is directly connected to the Kth data line without TFT, then the number of TFTs and MUX control signals is reduced, but feedthrough effects cause brightness differences and display uniformity deteriorates
Solution Approach 1:
The patent introduces a compensating capacitor as an intermediary element connected between the output channel and the Kth data line. This capacitor mediates the feedthrough effect by providing a compensation path for the parasitic capacitance, thereby maintaining display uniformity while keeping the direct connection structure that reduces device complexity
Solution Approach 2:
The patent converts the harmful feedthrough effect caused by parasitic capacitance into a beneficial compensation mechanism. By intentionally introducing a compensating capacitor with equal capacitance value, the harmful voltage fluctuations are counterbalanced, transforming the parasitic effect into a means for achieving uniform display brightness
2Manufacturing precision
If traditional 1:K DEMUX circuit with TFT for each data line is used, then display uniformity is maintained, but the size and power consumption increase
Solution Approach 1:
The patent extracts and removes the unnecessary TFT component from the connection between output channels and the Kth data line. By taking out this redundant switching element, the circuit size and power consumption are reduced while the compensating capacitor maintains the required display uniformity
Solution Approach 2:
The patent changes the circuit configuration parameter by replacing the TFT-based switching mechanism with a direct connection plus compensating capacitor approach. This parameter change reduces device complexity while maintaining performance through careful selection of capacitor values to compensate for parasitic effects
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 design reduces the size and power consumption of the DEMUX circuit while achieving better display uniformity by minimizing the number of MUX control signals and TFTs, ensuring consistent brightness across all pixel units.
Implementation Method 1
incorporating metal electrode plates to form coupling capacitance, allowing controlled potential changes to mitigate feedthrough effects
Data Source
AI summary
Disclosed in the present application is a demultiplexer and a driving method thereof, and a display panel having the demultiplexer. Each output channel is respectively connected to (K−1) data lines through (K−1) switching transistors and directly connected to another data line; each metal electrode plate is disposed nearby to the another data line respectively, so that a feedthrough effect on the another data line is close to that on other (K−1) data lines, thereby achieving better display uniformity on the display panel.