Touch Panel Conductive Member Thickness Ratio
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Solution Overview
Problem
Conductive members for touch panels face issues with lead wire fracture and external connection terminal breakage, especially when bent, due to stress concentration at the boundary between the two components.
Innovation Solution
A conductive member design where the ratio of external connection terminal thickness to lead wire thickness is optimized between 1.00 and 3.00, with the terminal being at least 1.00 μm thick and the wire less than 1.00 μm, to reduce stress concentration and prevent fractures during bending and pressure bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the external connection terminal is made thick to prevent breakage during pressure bonding, then the breakage resistance is improved, but the lead wire is more likely to fracture during bending
Solution Approach 1:
The patent applies parameter changes by precisely controlling the thickness ratio between the external connection terminal and the lead wire. By setting the terminal thickness to 1.00 μm or more and the lead wire thickness to less than 1.00 μm, achieving a thickness ratio of 3.00 or less, the design optimizes the mechanical properties to prevent both terminal breakage and wire fracture during bending and pressure bonding operations
Solution Approach 2:
The patent applies the curvature principle by designing a rounded boundary portion between the external connection terminal and the lead wire. This curved transition geometry eliminates stress concentration points that would otherwise occur at sharp corners, thereby preventing fracture of the lead wire while maintaining the structural integrity needed for terminal breakage resistance
2Reliability
If the lead wire is made thick to improve conductivity, then the electrical conductivity is improved, but the lead wire is more likely to fracture during bending
Solution Approach 1:
The patent applies parameter changes by optimizing the lead wire thickness parameter to be less than 1.00 μm. This thin wire design maintains sufficient electrical conductivity for touch panel applications while significantly improving flexibility and resistance to fracture during bending operations
3Strength
If the external connection terminal is made thick to prevent breakage, then the breakage resistance is improved, but stress concentrates on the boundary portion causing fracture
Solution Approach 1:
The patent applies the curvature principle by designing a rounded boundary portion between the external connection terminal and the lead wire. This curved transition geometry eliminates stress concentration points that would otherwise occur at sharp corners, thereby preventing fracture of the lead wire while maintaining the structural integrity needed for terminal breakage resistance
Solution Approach 2:
The patent applies parameter changes by controlling the thickness ratio D1/D2 to be 3.00 or less, where D1 is the terminal thickness and D2 is the lead wire thickness. This parameter optimization ensures that while the terminal is sufficiently thick to resist breakage, the boundary stress concentration is kept within acceptable limits
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 suppresses lead wire fracture and external connection terminal breakage, ensuring the conductive member's durability and reliability, even when subjected to bending and pressure bonding with display modules.
Implementation Method 1
The external connection terminal is likely to be electrically connected to a wiring line of the FPC or the like in many cases by being pressure-bonded through a so-called anisotropic conductive film (ACF)
Data Source
AI summary
A conductive member for a touch panel includes: a substrate; and a conductive layer that is disposed on at least one surface of the substrate, in which the conductive layer includes a plurality of detection electrodes, a plurality of lead wires led from the plurality of detection electrodes, and a plurality of external connection terminals connected to the plurality of lead wires, and a ratio of a thickness D1 of the external connection terminal to a thickness D2 of the lead wire satisfies 1.00<D1/D2≤3.00.