RFID Transponder Bonding Using Melted Contact Pads
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Solution Overview
Problem
The production of RFID transponders on carrying substrates, such as smart labels and intelligent packaging products, is cumbersome and costly due to the need for separate equipment and complex, time-consuming processes, particularly in connecting ICs to antennas, which requires high precision and results in long lead times and inefficient use of resources.
Innovation Solution
A roll-to-roll method and apparatus that electrically connects antenna elements on a first substrate to contact pads on a second substrate by heating the contact pads to a temperature at or below their characteristic melting point, allowing for a simple and fast connection with relatively low precision, using substrates with integrated circuits and contact pads made of materials like tin and bismuth alloys, and applying pressure to ensure adhesion and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional separate equipment and complex processes are used to produce RFID transponders, then manufacturing precision can be maintained, but production time increases and productivity decreases
Solution Approach 1:
The patent combines multiple separate production processes (antenna production, IC assembly, and label formation) into a single integrated roll-to-roll process. The antenna element and IC are connected in one continuous operation using thermal compression, eliminating the need for separate equipment and complex multi-step processes while maintaining connection precision through controlled heating and pressure application.
Solution Approach 2:
The patent replaces traditional mechanical connection methods (such as soldering or wire bonding requiring high precision alignment) with thermal compression bonding. By heating the contact pad to melt the material and then applying pressure, the connection is formed through phase change and adhesion rather than mechanical alignment, significantly reducing precision requirements and increasing production speed.
2Reliability
If traditional IC connection methods requiring high precision are used, then connection reliability is improved, but device complexity and production cost increase
Solution Approach 1:
The patent changes the physical state of the contact pad material by heating it to its melting point, transforming it from a solid to a liquid state. This phase change enables the material to flow and form reliable bonds with the antenna element. After cooling, the material solidifies creating a strong mechanical and electrical connection. This parameter change (temperature) simplifies the connection process while ensuring reliable bonding without complex alignment mechanisms.
3Reliability
If multiple separate production steps are used, then manufacturing control can be maintained, but lead time and work-in-progress storage requirements increase
Solution Approach 1:
The patent implements a continuous roll-to-roll production process where substrates continuously move through the production line. The antenna element and IC are connected in one continuous operation without stopping the substrate flow. This continuous process eliminates idle time between steps and reduces work-in-progress inventory requirements while maintaining quality control through consistent thermal and pressure parameters applied throughout the process.
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 method significantly simplifies and speeds up the connection process, reducing production time to milliseconds, enabling efficient, automated, and cost-effective production of RFID transponders with improved control over the process, allowing for efficient use of manufacturing facilities and equipment, and enabling the production of multiple products with minimal adjustments.
Implementation Method 1
heating the contact pad(s) to a temperature at least equal to a characteristic melting point of said at least contact pads, thereby electrically connecting the antenna element to said at least one contact pad
Data Source
AI summary
Method and apparatus for producing RFID transponders (400) arranged on a carrying substrate, comprising:providing a first substrate (100), the first substrate having at least one antenna element (101) arranged thereon, and preferably several antenna elements arranged sequentially thereon along a longitudinal extension of the first substrate, each antenna element being formed by an electrically conductive pattern; providing a second substrate (200), the second substrate (200) having at least one RFID strap, each RFID strap comprising an IC (202) and at least one contact pad (201) coupled to the IC, and preferably several RFID straps being arranged sequentially along a longitudinal extension of the second substrate; and electrically connecting an antenna element (101) on the first substrate to the at least one contact pad on the second substrate by bringing said first and second substrates together, thereby bringing said antenna element in mechanical contact with said at least one contact pad, and heating the contact pad(s) to a temperature at least equal to a characteristic melting point of said at least contact pads, thereby electrically connecting the antenna element to said at least one contact pad.