| 摘要 |
PROBLEM TO BE SOLVED: To provide a pyroelectirc infrared sensor of high reliability by securing the fundamental characteristics of a piezoelectric chopper. SOLUTION: This pyroelectric infrared sensor is equipped with an infrared ray sensing part 15 to sense infrared rays 16 emitted from an object, a shield plate 12 to shut off infrared rays 16 to be incident to the sensing part 15, an elastic shim 10 in flat plate shape whose one end is fixed and other end is fitted with the shield plate 12, and piezoelectric ceramic 11a and 11b provided on both surfaces of the shim 10 excluding some area. The shim 10, the ceramics 11a and 11b, and the shield plate 12 constitute a piezoelectric chopper which controls the incidence and shutoff of infrared rays 16 to the sensing part 15. The shim 10 fitted with shield plate 12 is divided into two parts, i.e., an arm 10a where piezoelectrics ceramic 11a and 11b is not provided and a drive part 10b where the ceramics 11a and 11b is formed, and thereby the shield plate 12 is displaced largely so that the fundamental characteristics of piezoelectric chopper are secured, and a high reliability is established. |
