An electrical relay that uses a conducting liquid in the switching mechanism.
In the relay, a pair of moveable switching contacts is attached to the free end
of a switch bar and positioned between a pair of fixed electrical contact pads.
The connections to the switching contacts and the fixed contact pads are shielded
by ground traces. A surface of each contact supports a droplet of a conducting
liquid, such as a liquid metal. A piezoelectric actuator is energized to push or
pull the switch bar and move the pair of switching contacts, closing the gap between
one of the fixed contact pads and one of the switching contacts, thereby causing
conducting liquid droplets to coalesce and form an electrical circuit. At the same
time, the gap between the other fixed contact pad and the other switching contact
is increased, causing conducting liquid droplets to separate and break an electrical
circuit. The piezoelectric actuator is then de-energized and the switching contacts
return to their starting positions. The volume of liquid metal is chosen so that
liquid metal droplets remain coalesced or separated because of surface tension
in the liquid. The relay is amenable to manufacture by micro-machining techniques.
