Touch Panel Cover-Substrate Guard Ring for ESD Protection
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Solution Overview
Problem
Electrostatic discharge (ESD) poses a significant threat to electrostatic capacitance type touch panels, leading to circuit destruction and malfunctions, and existing solutions to mitigate ESD often require widening the frame of the touch panel by incorporating guard rings.
Innovation Solution
A touch panel design where conductive layers on the cover substrate act as a guard ring, positioned along the periphery of sensor electrodes and signal wirings, without occupying additional space, thereby preventing ESD without enlarging the frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a guard ring is provided within the same layer as the sensor electrode to prevent ESD, then ESD protection is improved, but the frame of the touch panel is widened
Solution Approach 1:
The patent applies dimensionality change by moving the guard ring from the sensor electrode layer (first dimension) to the cover substrate layer (second dimension). The conductive layer is formed on the cover substrate at a position corresponding to the outer peripheral side of the sensor electrode, effectively utilizing the vertical dimension to separate protective functions across different layers without increasing the horizontal frame size.
Solution Approach 2:
The patent segments the guard ring function across multiple layers. The first guard ring is formed on the sensor substrate in the same layer as the sensor electrode, while the second guard ring is formed on the cover substrate. This segmentation allows the protective function to be distributed and achieved without requiring additional space in a single layer.
2Reliability
If a guard ring is provided to prevent ESD, then circuit destruction from ESD is prevented, but the touch panel structure becomes more complex
Solution Approach 1:
The conductive layer on the cover substrate serves multiple functions: it acts as a guard ring for ESD protection, serves as a reference potential line, and can be integrated with the touch panel's existing multi-layer structure. This multi-functionality reduces the need for separate dedicated ESD protection structures, thereby limiting the increase in overall structural 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
This design effectively mitigates ESD without increasing the panel's frame size, ensuring reliable operation while maintaining compactness.
Implementation Method 1
circuit destruction and a malfunction due to Electro-Static Discharge (ESD) become serious problems
Implementation Method 2
an electrostatic capacitance type touch panel... detect a change in an electrostatic capacitance in a position on a detection surface where the detection surface is touched
Data Source
AI summary
Disclosed herein is a touch panel including: a sensor substrate and a cover substrate stuck to each other. The sensor substrate includes a sensor electrode, and plural signal wirings electrically connected to the sensor electrode and extending along a periphery of the sensor electrode. The cover substrate includes one or plural conductive layers extending along the periphery of the sensor electrode and the plural signal wirings within an area not facing the sensor electrode and the plural signal wirings.