Thermoelectric infrared imaging sensors for automotive applications

Abstract

This paper describes three low-cost thermoelectric infrared imaging sensors having a 1,536, 2,304, and 10,800 element thermoelectric focal plane array (FPA) respectively and two experimental automotive application systems. The FPAs are basically fabricated with a conventional IC process and micromachining technologies and have a low cost potential. Among these sensors, the sensor having 2,304 elements provide high responsivity of 5,500 V/W and a very small size with adopting a vacuum-sealed package integrated with a wide-angle ZnS lens. One experimental system incorporated in the Nissan ASV-2 is a blind spot pedestrian warning system that employs four infrared imaging sensors. This system helps alert the driver to the presence of a pedestrian in a blind spot by detecting the infrared radiation emitted from the person's body. The system can also prevent the vehicle from moving in the direction of the pedestrian. The other is a rearview camera system with an infrared detection function. This system consists of a visible camera and infrared sensors, and it helps alert the driver to the presence of a pedestrian in a rear blind spot. Various issues that will need to be addressed in order to expand the automotive applications of IR imaging sensors in the future are also summarized. This performance is suitable for consumer electronics as well as automotive applications.