Fresnel lens array with spatial filtering for passive infrared motion sensor applications

In this work a Fresnel lens array for Passive InfraRed (PIR) motion sensors was designed, fabricated and tested. The resulting spatial filtering lens array presents the capability of distinguishing the presence of humans from small pets. Such array designed to operate in the visible range of the spectrum was manufactured on a Diamond-Like Carbon (DLC) thin film, using well-known microfabrication process steps. The optical testing was performed with an incoherent white light source. The fabricated lens was used to image an intensity input object onto a CCD array camera. The obtained results demonstrate that the optical power detected is attenuated for targets with inherently horizontal mass distribution (e.g. pets) while the optical power is enhanced for targets with vertical mass distribution (e.g. humans).