Touch Panel Detection Method for Conductive Liquid Differentiation
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Solution Overview
Problem
Conventional touch panel technologies struggle to distinguish between conductive liquids and external conductive objects due to the random size and shape of conductive liquids, which can cause uncertainties in voltage measurements, leading to mistaken detection.
Innovation Solution
A touch sensitive detecting method that involves setting a sensing electrode to floating, applying a high voltage to non-measuring sensing electrodes, measuring voltage differences, and determining the presence of external objects by comparing threshold voltages, thereby differentiating between conductive liquids and external conductive objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional mutual capacitance touch panel technology is used, then touch detection function is provided, but conductive liquid cannot be distinguished from external conductive objects causing mistaken detection
Solution Approach 1:
The detection process is divided into multiple sequential stages: first setting the sensing electrode to floating state, then applying sensing high voltage to non-measuring electrodes, measuring voltage, and finally comparing with threshold. This segmentation of the detection process allows differentiation between conductive liquids and external conductive objects through distinct voltage response patterns at each stage.
Solution Approach 2:
Before actual touch detection, the sensing electrode is pre-configured to floating state and non-measuring electrodes are set to sensing high voltage. This preliminary action establishes a controlled initial condition that enables subsequent voltage measurements to reliably distinguish between different types of conductive objects based on their electrical characteristics.
2Speed
If sensing electrode is continuously measured, then real-time detection is achieved, but conductive liquid causes voltage rise or drop that cannot be distinguished from external objects
Solution Approach 1:
The detection method employs periodic action by cycling the sensing electrode between floating state and ground voltage state, with measurement taken during specific phases. This periodic measurement approach, combined with comparing voltage differences against threshold values, enables real-time detection while achieving precise differentiation between conductive liquids and external conductive objects through consistent voltage response patterns.
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
Effectively differentiates between conductive liquids and external conductive objects on touch panels, reducing mistaken detections and improving accuracy in identifying real touch points.
Implementation Method 1
In the conventional mutual capacitance touch panel technology, part of charges from the driving voltage will be taken away when external conductive object such as a finger or a stylus approximates or touches the touch panel or screen. It causes the measured voltage on the sensing electrodes drop.
Data Source
AI summary
A touch sensitive detecting method, applicable to a touch panel or screen, comprises: setting a sensing electrode to floating; after the sensing electrode is set to floating, setting at least one non-measuring sensing electrode to a sensing high voltage; measuring the voltage of the sensing electrode; setting the sensing electrode to a ground voltage and stopping measurement; and determining whether an externally conducted object is approximating or touching the touch panel or screen nearby the sensing electrode by comparing a difference between a threshold voltage and the measured voltage of the sensing electrode.