Touch Panel ESD Protection Circuit Design
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Solution Overview
Problem
Capacitive touch screens are vulnerable to electrostatic discharge damage, particularly in in-cell designs where the sensing electrode is isolated from ground, leading to potential damage from accumulated electrostatic charges.
Innovation Solution
Incorporation of an electrostatic discharge (ESD) protection circuit with ESD protection units connected to the sensing electrode array and touch controller, which directs discharged current into ground, providing protection against electrostatic discharge damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the sensing electrode is isolated from ground in in-cell touch screen design, then the touch sensing function is achieved, but electrostatic charge accumulation causes damage to the sensing electrode and touch sensor IC
Solution Approach 1:
The patent introduces an ESD protection circuit as an intermediary component between the floating sensing electrode and the touch sensor IC. This protection circuit includes ESD protection units connected to both the sensing electrode array and the touch sensor IC, serving as a mediator that safely directs electrostatic discharge current to ground while protecting the sensitive components from direct exposure to harmful discharge currents.
2Object-affected harmful factors
If the sensing electrode behaves as an antenna for the touch sensor IC, then electrostatic charge accumulation occurs, but adding ESD protection circuit increases device complexity
Solution Approach 1:
The ESD protection circuit is segmented into multiple independent ESD protection units, with each unit connected to specific rows or columns of the sensing electrode array. This segmentation allows the protection function to be distributed across multiple units rather than requiring a single complex protection system, making the circuit more manageable and easier to integrate while maintaining effective ESD protection.
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 ESD protection circuit enhances the immunity of touch panels and electronic devices to electrostatic discharge damage, safeguarding the sensing electrode array and touch controller from harmful discharges.
Implementation Method 1
the behavior of the sensing electrode can also be regarded as an antenna for the touch sensor IC, which could damage the sensing electrode and/or the touch sensor IC if electrostatic charge accumulates on the sensing electrode and a sudden and momentary electric current discharges or flows towards the touch sensor IC
Data Source
AI summary
A touch panel and an electronic device are provided. The touch panel includes a sensing electrode array, a touch controller, and an electrostatic discharge (ESD) protection circuit. The sensing electrode array is arranged in two dimensional array of n rows and m columns for generating a sensing signal in response to a touch on the touch panel. The touch controller is operationally connected to the sensing electrode array for receiving the sensing signal and identifying the touch on the touch screen. The ESD protection circuit includes ESD protection units each being electrically connected to a corresponding row or column of the sensing electrode array and the touch controller for electrostatic discharge protection.