Touch Screen Panel Resistance Compensation Pattern for ESD Protection
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Solution Overview
Problem
Capacitive touch screen panels are vulnerable to damage from electrostatic discharge (ESD) and overvoltage due to varying resistance values in sensor signal lines connecting touch pads to the touch IC, which can lead to disconnection and errors in touch coordinate calculation.
Innovation Solution
A resistance compensation pattern is formed in the sensor signal lines, which can be meander-shaped and adjusted in width and length based on distance from the touch IC, to compensate for low resistance values and prevent damage from ESD or overvoltage, and can be integrated within the touch pad without altering its size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensor signal lines are made shorter to reduce resistance, then touch detection accuracy improves, but the touch IC cannot be positioned optimally and layout flexibility is reduced
Solution Approach 1:
The sensor signal line is extended in a meander pattern along the Y-axis direction (perpendicular to the main signal transmission path), adding a dimensional element to the routing. This allows the line to achieve sufficient length for proper resistance matching without increasing the direct distance between touch pads and touch IC, thus maintaining layout flexibility while achieving measurement precision requirements
2Reliability
If sensor signal lines are made longer to match resistance values, then ESD protection improves, but the signal transmission distance increases causing signal degradation
Solution Approach 1:
The meander extension is positioned specifically in regions where ESD protection is most needed (away from the touch IC), while keeping the direct signal path short. The signal line has different effective lengths in different segments: a short direct path for signal transmission and a longer meander path for resistance matching and ESD protection, thus achieving both reliability and minimizing signal degradation
3Reliability
If resistance compensation patterns are added to sensor signal lines, then ESD protection and resistance matching improve, but the overall line length and manufacturing complexity increase
Solution Approach 1:
The resistance compensation function is merged with the signal transmission path by forming the meander pattern directly as part of the sensor signal line rather than as a separate component. This integration allows the line to serve dual purposes: signal transmission and resistance matching/ESD protection, thereby improving reliability while minimizing manufacturing complexity
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 resistance compensation pattern effectively increases the resistance value of sensor signal lines, protecting them from ESD and overvoltage, while maintaining accurate touch detection and preventing errors in multi-touch calculations.
Implementation Method 1
a resistance value varying with a distance between the touch pad and the touch IC is lower than or equal to a set value, the sensor signal line forms a resistance compensation pattern compensating for the resistance value
Implementation Method 2
a capacitive touch screen panel is a device for determining whether the touch screen panel is touched based on a change of an electrical signal formed by capacitance that is generated between a finger or a touch input tool having conductivity like the finger and a touch pattern of the touch screen panel
Data Source
AI summary
Disclosed herein is a touch screen panel detecting a capacitive touch input applied by a finger or a touch input means having conductivity like the finger. According to the present invention, the touch screen panel includes: a touch pad forming touch electrostatic capacity (Ct) between the touch pad and the touch input means; and a sensor signal line connecting the touch pad and a touch integrated circuit (IC) to transmit a Ct signal changed on the touch pad to the touch IC, wherein when a resistance value varying with a distance between the touch pad and the touch IC is lower than or equal to a set value, the sensor signal line forms a resistance compensation pattern compensating for the resistance value.