Sheet Switch Dome Electrode Creep Deformation
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Solution Overview
Problem
Conventional sheet switches fail to reliably detect the removal of card readers from host devices, especially under high-temperature conditions due to creep deformation of resin sheets, causing contact electrodes and counter electrodes to remain in contact and not separate properly.
Innovation Solution
A sheet switch with a dome-shaped conductive metal contact electrode and a counter electrode separated by insulating members, where the contact electrode is not mounted on a resin sheet, and a metal sheet is used on the opposite side of the counter electrode to prevent creep deformation, ensuring the electrodes can separate reliably.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional sheet switch with contact electrode and counter electrode mounted on resin sheets is used, then the device is lightweight and easy to manufacture, but under high temperatures the resin sheets undergo creep deformation causing the electrodes to remain in contact and fail to detect removal properly
Solution Approach 1:
The patent changes the material parameter of the contact electrode from resin-mounted to metal dome-shaped, which fundamentally alters the thermal and mechanical properties. The metal dome electrode has high thermal stability and elastic recovery capability, preventing creep deformation under high temperatures and ensuring reliable contact separation for accurate removal detection.
Solution Approach 2:
The patent creates a composite structure by combining the metal dome-shaped contact electrode with the resin counter sheet. The metal dome provides thermal stability and elastic recovery, while the resin counter sheet maintains the lightweight and easy manufacturing advantages. This composite approach resolves the contradiction between reliability under high temperature and ease of manufacture.
2Reliability
If the contact electrode is formed in a dome shape with metal, then creep deformation is prevented and detection reliability is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent extracts the contact electrode from the resin sheet substrate and forms it as a separate metal dome-shaped component. This extraction allows the contact electrode to be manufactured independently with precise dome geometry using metal forming techniques, then mounted on the counter sheet. This approach maintains detection reliability while simplifying the overall manufacturing process by separating critical functions.
Solution Approach 2:
The patent employs a dome-shaped (spheroidal) contact electrode instead of a flat contact. The curved geometry provides automatic centering, uniform contact pressure distribution, and elastic recovery capability. The dome shape is formed through standard metal forming processes, making it manufacturable while providing superior mechanical properties for reliable detection.
3Stability of the object's composition
If a metal sheet is disposed on the opposite side of the counter electrode with insulating members, then creep deformation of the counter electrode is prevented, but the device complexity increases
Solution Approach 1:
The patent introduces insulating members as intermediary elements between the metal sheet and the counter electrode. These insulating members serve multiple functions: they prevent electrical shorting between the metal sheet and counter electrode, provide mechanical support to prevent creep deformation of the counter electrode, and maintain the thin-profile structure. This intermediary approach adds structural stability without significantly increasing device 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
The solution effectively prevents creep deformation on both the contact and counter electrodes, allowing for accurate detection of card reader removal from the host device, even under high-temperature conditions, and can be used in card readers to meet PCI-PED or PCI-UPT standards.
Implementation Method 1
due to creep deformation of the surface sheet or counter sheet, the contact electrode and the counter electrode stay in contact and do not separate
Implementation Method 2
a metal sheet made of metal that is disposed on the opposite side of the counter electrode from the side facing the contact electrode with insulating members interposed therebetween
Data Source
AI summary
Provided is a sheet switch suitable as a sensing mechanism to sense the removal of a subordinate device from a host device. Specifically, the sheet switch is provided with a contact electrode formed in a dome shape with a conductive metal, a counter electrode disposed facing the contact electrode, and a metal sheet made of metal that is disposed on the opposite side of the counter electrode from the side facing the contact electrode with insulating members interposed therebetween. The sheet switch becomes conductive when the contact electrode and the counter electrode touch.