Touch Panel Charge Minimization via Opposite Polarity Voltage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing touch systems using mutual capacitive methods for touch position detection face performance issues due to charges accumulating at the electrode associated with the display panel, caused by parasitic capacitances between transmit and receive electrodes, which affect the accuracy of touch position detection.
Innovation Solution
A method is introduced where a voltage generating circuit applies a first voltage of one polarity to a selected transmit electrode and a second voltage of opposite polarity to adjacent transmit electrodes, concurrently minimizing the charges accumulated at the display panel electrode by exploiting parasitic capacitances to offset the initial voltage-induced charges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensing signals are applied to transmit electrodes to detect touch position, then touch position detection capability is enabled, but charges accumulate at the display panel electrode due to parasitic capacitances, degrading touch system performance
Solution Approach 1:
The patent applies preliminary anti-action by introducing a compensation signal with opposite polarity to the sensing signal. This compensation signal is applied to adjacent transmit electrodes before or during the sensing operation to pre-counteract the charge accumulation effect. By applying the opposite polarity voltage in advance, the parasitic capacitance charges are neutralized before they can adversely affect the touch detection accuracy, thus resolving the contradiction between enabling touch detection and preventing performance degradation
2Ease of operation
If voltage pulses are applied to transmit electrodes for mutual capacitance measurement, then touch detection function is achieved, but parasitic capacitances cause charge coupling to the common electrode, creating measurement errors
Solution Approach 1:
The patent uses an intermediary approach by introducing compensation signals as a mediating element between the sensing signals and the parasitic capacitances. These compensation signals act as intermediaries that transfer opposite charges to neutralize the parasitic capacitance effects. The compensation signals serve as a bridge that allows the sensing operation to proceed while simultaneously counteracting the harmful charge coupling through the parasitic capacitances to the common electrode
3Power
If charges are accumulated at the common electrode through parasitic capacitances, then voltage pulses can be applied to transmit electrodes, but this charge accumulation adversely affects touch system performance
Solution Approach 1:
The patent applies the blessing in disguise principle by converting the harmful charge accumulation effect into a beneficial neutralization process. Instead of trying to eliminate parasitic capacitances entirely, the invention utilizes the same parasitic capacitances to its advantage by applying compensation signals that generate opposite charges through the parasitic paths. This converts the harmful charge coupling into a useful charge neutralization mechanism, maintaining the ability to apply voltage pulses while improving system reliability
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 minimizes the charges at the display panel electrode, enhancing the accuracy and reliability of touch position detection by mitigating the adverse effects of parasitic capacitances on the touch system's performance.
Implementation Method 1
charges corresponding to the sensing signals are coupled to the electrode of the display panel because of the presence of parasitic capacitances formed between the transmit electrodes and that particular electrode
Data Source
AI summary
A touch system including a display panel associated with a first electrode, a touch panel having a plurality of touch electrodes having a plurality of transmit electrodes and a plurality of receive electrodes, and a voltage generating circuit is provided. When a mutual capacitance between a selected transmit electrode and a selected receive electrode is measured, the voltage generating circuit applies a first voltage of a first polarity to the selected transmit electrode, and substantially concurrently applies a second voltage of a second polarity that is opposite to the first polarity to at least one other transmit electrode for minimizing charges associated with an application of the first voltage to the selected transmit electrode and accumulated at the first electrode.