Touch Screen Panel Copper Pad Corrosion Protection
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Solution Overview
Problem
Existing touch screen panels face challenges in maintaining the reliability of touch sensors due to potential corrosion of pads made from low resistance metals, which can lead to degradation and defects, especially in flexible electronic devices.
Innovation Solution
The touch screen panel incorporates a design with pads made of transparent conductive materials and metal nanowires, where a copper pad is used with a protective layer to prevent corrosion, and the touch electrodes are arranged in rows and columns with decreasing size proximity to the pads, ensuring effective touch sensing while minimizing exposure of the copper pad.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If pads are made of low resistance metal (copper) to ensure high conductivity, then electrical conductivity is improved, but the pads become prone to corrosion and degradation
Solution Approach 1:
A protective layer is introduced as an intermediary between the copper pad and the external environment. This protective layer prevents direct contact between copper and corrosive elements while maintaining electrical conductivity through the pad structure, thus resolving the contradiction between high conductivity and corrosion resistance
Solution Approach 2:
The pad structure is designed as a composite system combining copper (for conductivity) with a protective coating material (for corrosion resistance). This composite approach allows the pad to simultaneously achieve high electrical conductivity and enhanced durability against corrosion
2Reliability
If pad area is increased to improve connection reliability, then connection strength is improved, but the exposed copper surface area increases leading to higher corrosion risk
Solution Approach 1:
The protective layer serves as a mediator that allows the pad to maintain adequate connection area for reliability while preventing corrosion. The protective coating covers the copper surface, enabling the pad to have sufficient exposed area for mechanical connection without proportionally increasing corrosion risk
3Measurement precision
If touch electrode size is decreased near pads to improve sensing precision, then measurement precision is improved, but the overall touch sensing area is reduced
Solution Approach 1:
The touch electrode structure is designed with varying sizes according to local requirements: smaller electrodes near pads for high precision sensing in critical areas, and larger electrodes in other regions to maintain overall sensing area. This local differentiation resolves the contradiction between precision and total sensing area
Data Source
AI summary
A touch screen panel includes a substrate, a plurality of touch electrodes in a touch area of the substrate, the touch electrodes sensing a touch, a connection line connected to a touch electrode of the plurality of touch electrodes, and a pad connected to one end of the connection line. The pad includes a first pad, a second pad on the first pad within a boundary line of the first pad, and a third pad covering a top surface and a side surface of the second pad.