Eliminating Parasitic Capacitance in Full In-Cell Touch Panels
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Solution Overview
Problem
Full in-cell touch panels experience parasitic capacitance that affects the input touch scanning signal and reduces the signal-to-noise ratio during touch scanning.
Innovation Solution
A method and device that eliminate parasitic capacitance by inputting simulation signals with waveforms similar to the touch scanning signal to the source electrode lines, multiplex lines, and gate lines during the touch scanning period, reducing voltage differences and charging effects between electrode lines and sensor pads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If full in-cell touch technology is adopted to reduce module thickness and increase transmittance, then manufacturing precision and structural integration are improved, but parasitic capacitance increases which degrades signal quality during touch scanning
Solution Approach 1:
The patent applies preliminary action by inputting simulation signals to the gate lines, source electrode lines, and multiplex lines before the actual touch scanning signal is applied. This pre-charging or pre-discharging of the electrode lines eliminates parasitic capacitance effects in advance, allowing the main touch scanning signal to be received without interference from capacitive coupling between adjacent lines.
2Measurement precision
If simulation signals are input to electrode lines to eliminate parasitic capacitance, then signal-to-noise ratio is improved, but device complexity increases due to additional signal input modules
Solution Approach 1:
The patent applies universality by designing the simulation signal input modules to serve multiple functions: they can input simulation signals to different electrode lines (gate lines, source electrode lines, multiplex lines) depending on the scanning period, and the same modular structure can be reused across different parts of the touch panel, reducing overall device complexity while maintaining high signal-to-noise ratio.
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 approach effectively reduces the influence of parasitic capacitance on the input touch scanning signal, enhancing the signal-to-noise ratio and improving the performance of full in-cell touch panels.
Implementation Method 1
parasitic capacitance formed among the plurality of gate lines, the plurality of source electrode lines, the plurality of common electrode lines and the plurality of sensor pads
Data Source
AI summary
The disclosure discloses an elimination method of parasitic capacitance and a device. During a touch scanning period, inputting a first simulation signal to source electrode lines and inputting a second simulation signal to multiplex lines can eliminate parasitic capacitance. Waveforms of the first simulation signal and a touch scanning signal input in a common electrode are identical or similar, waveforms of the second simulation signal and the touch scanning signal input in the common electrode are similar, waveforms of the third simulation signal and the touch scanning signal input in the common electrode are similar, a second simulation waveform includes a first target high level, a second target high level, a first target low level and a second target low level that are generated by different modules, the first target high level>the second target high level>the first target low level>the second target low level.