Membrane Switch Enhances Reliability

DuPont Microcircuit Materials announces two new screen-printable, silver-based polymer thick film (PTF) conductive compositions developed for use in Membrane switches apllications, which significantly reduce silver migration and increase circuit life and reliability. The newly developed membrane switch application uses the silver PTF conductors, which have been tested for 1,000 hours at 85°C and 85 percent relative humidity under bias (10V DC), and considerably reduce silver migration compared to conventional technology. New silver migration-resistant conductor technology enhances membrane switch reliability and may enable new ost-effective approaches to circuit design. 

Silver PTF conductors have been used for more than 20 years in the production of low voltage membrane touch switches (MTS) for use in dishwashers, microwave ovens, and washer/dryers. High conductivity and the relatively low cost of silver conductors are advantages but silver conductors can be subject to "silver migration." Silver migration occurs when a silver conductor is exposed to moisture under a bias (5V, for example). Dendrites grow from an exposed silver conductor trace to an adjacent trace, effectively causing a short circuit and rendering the circuit inoperative. DuPont APP11 and APP21 conductive compositions significantly reduce growth of these dendrites.

Related Links:

Membrane Switches Overview and Application

Typical Membrane Switch Design and Construction

Membrane Switches Manufacturing Companies