Electrostatic Capacitance Touch Panel Shielding for Narrow Picture Frame
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Solution Overview
Problem
The electrostatic-capacitance type touch panels with one-sided feeding face challenges in minimizing the width of the picture frame outside the effective touch region while maintaining durability and preventing erroneous touch position recognition due to capacitive coupling between lead lines and inspection pads.
Innovation Solution
The implementation of an electrostatic capacitance type touch panel with alternately connected lead lines outside the effective touch region, where inspection pads are placed on the opposite side of the electrodes, and a shield electrode is introduced between the lead lines and inspection pads to suppress capacitive coupling by applying a voltage equal to the drive voltage to the shield electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If lead lines are arranged outside the effective touch region to prevent erroneous touch position recognition, then touch position accuracy is improved, but the picture frame width increases
Solution Approach 1:
The patent relocates inspection pads from the lateral sides (outside effective touch region) to the longitudinal ends of Y electrodes. This dimensional shift allows inspection functionality to be integrated within the effective touch region boundaries, eliminating the need for extended picture frame width while maintaining touch position accuracy through proper shielding of lead lines.
Solution Approach 2:
A shield electrode is introduced as an intermediary element between lead lines and inspection pads. This shield electrode, connected to ground potential, blocks capacitive coupling between lead lines and inspection pads, preventing erroneous touch position recognition while allowing compact arrangement within the effective touch region.
2Reliability
If inspection pads are arranged on the other side of Y electrodes to enable disconnection inspection, then reliability is improved, but the picture frame width increases due to capacitive coupling concerns
Solution Approach 1:
Inspection pads are relocated from lateral positions (requiring extended picture frame width) to longitudinal end positions of Y electrodes. This repositioning enables disconnection inspection functionality while keeping all components within the effective touch region boundaries, eliminating the need for increased picture frame width.
Solution Approach 2:
A shield electrode is positioned between lead lines and inspection pads to block capacitive coupling. The shield electrode is connected to ground potential and effectively isolates the inspection pads from lead line interference, enabling reliable disconnection inspection without extending the picture frame width.
3Length of stationary object
If lead lines are led out alternately from one side of Y electrodes to minimize picture frame width, then picture frame width is reduced, but capacitive coupling with inspection pads causes erroneous touch position recognition
Solution Approach 1:
A shield electrode is introduced as a ground-connected intermediary between lead lines and inspection pads. This shield electrode blocks capacitive coupling paths, preventing erroneous touch position recognition while allowing lead lines to be arranged compactly with alternate connection from one side, thus maintaining minimal picture frame width.
Solution Approach 2:
The patent repositions inspection pads to the longitudinal ends of Y electrodes rather than lateral sides. This dimensional reconfiguration allows lead lines to be led out alternately from one side without capacitive coupling issues, maintaining minimal picture frame width while preventing touch position errors through proper spatial separation.
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 configuration effectively narrows the picture frame width outside the effective touch region, enhances the accuracy of position determination, and maintains high durability by eliminating disconnection inspections, thus improving the design and manufacturing yield of the touch panel.
Implementation Method 1
to prevent an erroneous recognition of a touch position in the touch panel which is caused by capacitive coupling between a lead line arranged outside the effective touch region and the inspection pad
Implementation Method 2
a shield electrode is provided between the lead lines and the respective inspection pads, and a voltage equal to the drive voltage supplied to the Y electrodes is supplied to the shield electrode
Data Source
AI summary
Provided is an electrostatic capacitance type touch panel in which lead lines are alternately connected to one end portions of a plurality of Y electrodes, the respective lead lines are formed outside an effective touch region, and are connected to terminals which are formed corresponding to the respective lead lines, inspection pads which are connected with the Y electrodes respectively are formed over end portions of the respective Y electrodes on a side where the lead lines are not connected to the respective Y electrodes, the plurality of inspection pads are formed in a region where the lead lines are formed outside the effective touch region, a shield electrode is provided between the lead lines and the respective inspection pads, and a voltage equal to a drive voltage supplied to the Y electrodes is supplied to the shield electrode.