Pyroelectric Infrared Sensor Using Modified PbTiO<SUB>3</SUB> Ceramics

Abstract

Pyroelectric infrared sensor using (Pb1-x, Cax)[(Co1/2W1/2)Ti]O3 ceramics have been studied by changing Ca concentration, the infrared ray absorbing film diameter, and the electromagnetic wave shielding materials for packaging. With an increase in Ca concentration from x=0.05 to 0.28, the pyroelectric coefficient P and the figure of merit Fv increased and reached 4.43×10-8 Ccm-2°C-1, and 0.61×10-10 CcmJ-1, respectively. Pyroelectric characteristics have been improved to twice the values for the PbTiO3 ceramics containing small amounts of La and Mn. The spontaneous polarization Ps of the ceramics increases to a great extent in the Ca concentration range of x=0.20-0.30, and reaches larger values of 40-42μC/cm2 than 33μC/cm2 of the c-axis oriented sputtering PbTiO3 thin film. With a decrease in the infrared ray absorbing film diameter, the responsivity Rv is improved to 140-180% in the range of 0.15-0.4Hz. The Responsivity Rv for the sensor with a Si filter window shows high values of 860 V/W.It was found that the pyroelectric infrared sensor using (Pb1-x, Cax)[(CO1/2W1/2)Ti]O3 ceramics is appropriate for use as a human body sensor.