Sophisticated thermal processing

At the heart of the Irisys systems are small wafers of specially formulated lead zirconate titanate (PZT), a pyro-electric ceramic that develops a voltage difference across two of its faces when it experiences a temperature change. When bonded to a read-out circuit, it can be used as a sensor to identify and count people.

PZT is produced initially in powder form and then subjected by Irisys to a two-stage process to densify and compress. The first stage involves cold-pressing the powder and then sintering in one of six Carbolite chamber furnaces at temperatures above 1000ºC for several hours to form 50mm or 75mm discs.

After cooling, the discs are pressed at up to 40 tonne in conjunction with precisely controlled temperatures in the Carbolite furnaces.