| 摘要 |
PROBLEM TO BE SOLVED: To provide a gas sensor causing little decline of a propagation efficiency caused by liquid included in a measuring gas, and allowing to surely mount an ultrasonic element. SOLUTION: This gas sensor is equipped with an element case 42, a detection element body 40 having a piezoelectric element 51, an acoustic matching plate 50 and a protective film 48, and a passage forming member 20 having a storage part 22 for arranging the protective film 48 face to face with a measuring chamber 28. The opening lower end 43a of the element case 42 having a step part 46 formed thereon is a lyophilic site having less surface tension to a liquid than the center site of the protective film 48, and prevents the liquid from adhering onto an ultrasonic emission surface of the protective film 48. COPYRIGHT: (C)2003,JPO
|
