Infrared radiation sensitive device

摘要

A pyroelectric infrared sensor device (10) with improved relative detectivity and with which it is easier to change the relative detectivity, and also with reduced manufacturing cost. This sensor device (10) includes a pyroelectric unit (12) having an alternating lamination of internal electrodes (16) and pyroelectric layers (14) with a predetermined thickness t. The ends of the internal electrodes (16) which extend perpendicular to the length direction thereof are respectively exposed at alternate terminal surfaces of the pyroelectric unit (12) and external electrodes (18) are connected to the terminal ends of those internal electrodes (16), respectively. The pyroelectric infrared sensor device (10) is horizontally polarized between the internal electrodes (16) via the external electrodes (18) with respect to the infrared light receiving plane thereof. The ends of the internal electrodes (16) perpendicular to the width direction thereof are exposed at the top and bottom surfaces of the pyroelectric unit (12) in such a manner that its top surface side will act as the light receiving plane of the pyroelectric infrared sensor device (10).