Résumé : |
Polymer thick film (PTF) technology for printed circuits has been used for a long time. Soldering onto the PTF has always been a problem and a multitude of ways have been devised to get around it. A flexible solution to solderless surface mount is a fully additive, fully compatible package of polymer thick film inks designed to enhance printed circuit technology. The package includes silver ink, dielectric ink, carbon ink, silver adhesive paste, and encapsulating photopolymer. These are used to attach surface mount devices (SMD) onto flexible polyester film when applied by screen print, stencil, and dot dispense methods. Early applications started with chip mount resistors, LEDs, or diodes. Improvements in technology have led to robust production with surface mounted active components.
Why should we use surface mount technology for flexible printed circuits? Everyone is trying to conform as quickly as possible to the Green revolution. Surface mount technology (SMT) for flexible printed circuitry (FPC) provides a clear means to lower costs and comply with environmental pressures while enhancing printed circuit functionality.
Performance is equal to copper etched circuits at speeds of up to 20 MHz at substantially lower costs, lighter weights and with the ability to be packaged into three dimensional cavities. Circuits for full travel keyboards, membrane switches, games, medical applications, sensors, displays and digitizers have used additive SMT worldwide for more than 10 years. |