Bootstrap Capacitor Input Control Circuit for In-Cell Touch Signal Stability
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Solution Overview
Problem
In In-Cell Touch technology, the division of common electrodes into blocks increases overall impedance, leading to signal fluctuations on common electrode blocks during pixel charging, causing display abnormalities like horizontal stripes during Cell Test due to parasitic capacitance between the gate scan line and common electrode block, which results in inefficient signal recovery.
Innovation Solution
An input control circuit comprising an input module, output module, driving module, reset module, and bootstrap capacitor, where the input module transmits an input signal to a pull-up node, the output module transmits a clock signal, the driving module transmits a common signal to the common electrode block, and the reset module resets the pull-up node, with a bootstrap capacitor enhancing signal transmission to achieve faster recovery of signal fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the common electrode is divided into multiple common electrode blocks, then the touch structure can be embedded into the display panel, but the overall impedance increases causing signal fluctuations
Solution Approach 1:
The common electrode is divided into multiple common electrode blocks to enable in-cell touch integration. Each block is independently controlled by separate switching elements, allowing localized signal management that mitigates the impedance increase effect while maintaining touch functionality.
Solution Approach 2:
Bootstrap capacitors are introduced as intermediary components connected to the pull-up nodes of each common electrode block. These capacitors actively compensate for signal fluctuations by providing additional charge during voltage drops, thereby stabilizing the common signal despite the increased overall impedance from segmentation.
2Adaptability or versatility
If the common signal is transmitted through switching transistors and touch leads, then the multiplexed common electrode can function for both display and touch, but parasitic capacitance causes signal fluctuations during pixel charging
Solution Approach 1:
Bootstrap capacitors serve as intermediary energy storage elements that decouple the common signal transmission from the parasitic capacitance effects. By providing local charge compensation at each common electrode block, they prevent the parasitic capacitance between gate scan lines and common electrode blocks from causing signal fluctuations.
Solution Approach 2:
The switching elements are designed to transmit the common signal to each common electrode block in a predetermined sequence synchronized with the pixel charging cycles. This preliminary timing arrangement ensures that common signal updates occur at optimal moments, minimizing interference from parasitic capacitance effects during critical charging phases.
3Reliability
If the common signal recovery is slow due to high impedance, then display abnormalities like horizontal stripes occur during Cell Test, but increasing signal transmission strength may affect other circuit components
Solution Approach 1:
Bootstrap capacitors act as local energy reservoirs that provide rapid charge compensation without requiring increased signal transmission strength from the main circuit. This intermediary approach accelerates signal recovery at each common electrode block independently, eliminating horizontal stripe artifacts during Cell Test while avoiding excessive stress on the overall circuit components.
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 input control circuit facilitates faster recovery of common signal fluctuations, overcoming horizontal stripes during Cell Test and improving detection efficiency by ensuring the common signal is transmitted in a higher saturated state with reduced impedance.
Implementation Method 1
pulling up the signal at the pull up node under the bootstrap effect of the bootstrap capacitor
Data Source
AI summary
The present disclosure relates to the field of display technology and, in particular, to an input control circuit and an input control circuit method; an input control device; and a display panel. The input control circuit includes an input module configured to transmit an input signal to the pull up node in response to the input signal; an output module configured to transmit a clock signal to the signal output terminal in response to a voltage signal at the pull up node; a driving module configured to transmit a common signal to the common electrode block in response to the voltage signal at the pull up node; a reset module configured to transmit a power signal to the pull up node in response to a reset signal; and a bootstrap capacitor connected between the pull up node and the signal output terminal.