Electrostatic Capacitance Touch Panel Inspection Electrode Design
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Solution Overview
Problem
The electrostatic-capacitance type touch panels with one-sided feeding face challenges in detecting disconnection or increased resistance in electrodes and lead lines, making it difficult to identify defective panels during manufacturing.
Innovation Solution
Incorporating inspection electrodes laminated with insulation films at the ends of X and Y electrodes, where lead lines are not connected, allows for the detection of disconnection or resistance issues by supplying a voltage for inspection during the manufacturing process, and matching the drive voltage during operation to minimize capacitive coupling and improve position accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If one-sided feeding is adopted to supply drive voltage to electrodes, then device complexity is reduced and ease of manufacture is improved, but difficulty of detecting and measuring disconnection or resistance increase occurs
Solution Approach 1:
The touch panel is divided into two functionally independent parts: the drive circuitry (supplying voltage to X and Y electrodes) and the inspection circuitry (supplying voltage to inspection electrodes). This segmentation allows the inspection function to operate independently without interfering with the drive function, enabling detection of disconnections and resistance increases while maintaining the simple one-sided feeding structure.
Solution Approach 2:
Inspection electrodes are introduced as intermediary elements between the substrate and the lead lines. These inspection electrodes are positioned to face the lead lines and electrodes, creating a capacitive coupling path that allows electrical inspection of the lead lines and electrodes without direct electrical contact, thus enabling detection while maintaining the one-sided feeding simplicity.
2Measurement precision
If inspection electrodes are added to detect electrode issues, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The inspection electrodes serve multiple functions: they enable detection of disconnections, detection of resistance increases, and verification of lead line integrity. By making these electrodes multi-functional, the patent achieves high measurement precision without adding separate dedicated components for each inspection purpose, thus limiting the increase in device complexity.
Solution Approach 2:
The inspection electrodes are positioned in a different spatial dimension (on the substrate side) relative to the lead lines and electrodes (on the front surface side), creating a capacitive coupling relationship. This dimensional arrangement allows inspection functionality to be added without increasing the complexity of the front surface electrode structure, maintaining simplicity while enabling precise measurement.
3Ease of manufacture
If drive voltage is supplied from one side, then ease of manufacture is improved, but reliability of detecting electrode faults deteriorates
Solution Approach 1:
The inspection electrodes are pre-positioned and connected to the substrate before final assembly, creating a built-in inspection system. This preliminary arrangement ensures that the inspection capability is integrated into the manufacturing process, allowing reliable detection of faults while maintaining the simple one-sided feeding structure for drive voltage supply.
Solution Approach 2:
The inspection system provides feedback about the electrical state of lead lines and electrodes by measuring capacitance values. This feedback mechanism enables continuous monitoring of component integrity, enhancing reliability while the one-sided feeding maintains manufacturing simplicity. The feedback loop allows detection of faults that would otherwise go unnoticed in a simple one-sided feeding configuration.
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 solution enables effective detection of electrode and lead line issues, reducing defective panel production and enhancing the accuracy of touch position determination by suppressing cross-talk and ensuring high yield and accuracy in touch panel manufacturing.
Implementation Method 1
the input processing part detects the increase of the capacitance, and calculates input coordinates based on a signal indicative of a change in capacitance detected by each electrode
Implementation Method 2
an insulation film sandwiched therebetween on a side where the lead lines are not connected
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
Provided is an electrostatic capacitance type touch panel, wherein lead lines (LY1 - LY6) are connected to respective end portions of at least either one of the X electrodes and the Y electrodes respectively, the touch panel further comprises an inspection electrode (KY) which is laminated to respective end portions of the at least either one of the X electrodes and the Y electrodes with an insulation film sandwiched therebetween on a side where the lead lines are not connected to the at least either one of the X electrodes and the Y electrodes, and a voltage for inspection is supplied to the inspection electrode during an inspection time and a voltage at the same phase as the drive voltage supplied to the at least either one of the X electrodes and the Y electrodes is supplied to the inspection electrode during a usual operation time.