Touch Driving Device Noise Removal via Parasitic Capacitance Subtraction
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Solution Overview
Problem
As panels become thinner, parasitic capacitance between touch sensors and display electrodes increases, leading to noise interference, which reduces signal sensitivity in touch sensors, especially with higher refresh rates and resolutions.
Innovation Solution
A touch driving device that includes a receiving unit to process signals from both touch sensors and display electrodes, using filters and amplifiers to remove noise signals and generate clean touch signals, thereby enhancing signal sensitivity by integrating reference voltage signals and outputting the integrated signal through a capacitor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If panels are made thinner to reduce size and improve integration, then panel thickness is reduced, but parasitic capacitance between touch sensors and display electrodes increases, leading to noise interference
Solution Approach 1:
The patent extracts the noise signal from the sensor signal by separately receiving and processing the display electrode signal. The receiving unit generates a noise signal from the display electrode signal and subtracts it from the sensor signal, effectively removing the harmful noise component while preserving the useful touch sensor signal.
Solution Approach 2:
The patent introduces an intermediary processing mechanism - the receiving unit with filter and amplifier components - that mediates between the noisy sensor signal and the final processed signal. This intermediary unit separates, filters, and combines signals to eliminate noise interference caused by parasitic capacitance.
2Productivity
If display refresh rate is increased to improve display performance, then display quality is enhanced, but noise flowing into touch sensors increases due to faster voltage changes
Solution Approach 1:
The patent implements a feedback mechanism where the receiving unit continuously monitors both the sensor signal and display electrode signal, dynamically generates the corresponding noise signal, and subtracts it in real-time. This feedback loop ensures that noise cancellation keeps pace with rapidly changing display voltages at high refresh rates.
Solution Approach 2:
The receiving unit serves as an intermediary that processes the display electrode signal separately before combining it with the sensor signal. This intermediary processing allows the system to handle fast-varying display voltages without directly transmitting noise to the touch sensor output.
3Object-affected harmful factors
If parasitic capacitance is reduced by increasing distance between touch sensor and display electrode, then noise interference is reduced, but device complexity and space requirements increase
Solution Approach 1:
The patent replaces the mechanical/physical solution of increasing physical distance to reduce parasitic capacitance with an electronic signal processing solution. Instead of physically separating components, the system uses signal reception, filtering, and mathematical subtraction to eliminate noise, maintaining compact device structure while achieving noise reduction.
4Measurement precision
If signal processing is enhanced to remove noise, then signal sensitivity is improved, but device complexity increases due to additional processing components
Solution Approach 1:
The patent combines multiple functions (signal reception, filtering, amplification, and noise subtraction) into a single integrated receiving unit. This merging of functions achieves high signal sensitivity through comprehensive noise removal while minimizing the increase in device complexity by consolidating processing components rather than adding separate units for each function.
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 solution effectively minimizes noise interference, increasing the signal sensitivity of touch sensors and improving their performance in thinner panels with higher display driving voltage noise.
Implementation Method 1
parasitic capacitance between a touch sensor and a display electrode, such as a data line, a gate line, a common electrode, a cathode electrode, etc.
Implementation Method 2
the receiving unit may process a signal, received from the display electrode, by using at least one of a filter and an amplifier.
Implementation Method 3
the receiving unit may process a signal, received from the display electrode, by using at least one of a filter and an amplifier.
Implementation Method 4
the receiving unit may generate the touch signal by integrating a signal obtained by removing the noise signal and a reference voltage signal from the sensor signal.
Implementation Method 5
the receiving unit integrates a signal, obtained by removing the noise signal from the sensor signal, into a capacitor connected to the one terminal and an output terminal of the integrator
Data Source
AI summary
A technique is disclosed for sensing a display electrode in addition to a touch sensor in order to remove noise delivered from the display electrode to the touch sensor through parasitic capacitance, and generating a touch signal by removing a noise signal, generated from the display electrode, from a sensor signal generated by the touch sensor.