Takeshi Kamata

Pyroelectric linear array infrared sensors made of La-modified PbTiO3 thin films and their applications

A new pyroelectric linear array IR sensor has been developed by using the c-axis oriented La- modified PbTiO3 (PLT:Pb1-xLaxTi1-x/4O3) thin films. The PLT thin films were prepared on (100) MgO single crystal substrates by rf-magnetron sputtering method. Without a poling treatment, this PLT thin film has high pyroelectric properties (x equals 0.1; PL10, (epsilon) r equals 200, pyroelectric coefficient: (gamma) equals 5.5 X 10-8 C/cm2K). For minimizing the substantial heat capacity, these IR sensors have a unique structure in which eight elements of pyroelectric thin films are supported only by polyimide resin films (thickness equals 3 micrometer). This sensor was fabricated by etching MgO substrates off thoroughly. These IR sensors have a high specific detectivity D*(500,30,1) of 3.5 X 108 cmHz1/2/W. A new compact IR sensing system using this linear array sensor can measure thermal distribution (8 X 64) by horizontal sweeping of the vertical linear array elements. The image processing with neural network concept makes possible high-accuracy using a few data from the sensor elements. This sensor system is applied to a new type of room air conditioners to improve the comfort level control.