| 摘要 |
PROBLEM TO BE SOLVED: To provide a pressure wave generator wherein occurrence of cracking and a damage of a thermal insulation layer and a heating element 3 caused by the cracking can be prevented by dispersing a compression stress even if the thermal insulation layer 2 is oxidized by oxygen in air and the compression stress is generated because of volume expansion. SOLUTION: The pressure wave generator is provided with: a substrate 1; a porous thermal insulation layer 2 formed on one side of the substrate 1 in the thickness direction; and a thin film heating element 3 formed on the thermal insulation layer 2 and generating a pressure wave by heat exchange between the heating element 3 and a medium. Assuming that the distribution of the thickness of the thermal insulation layer 2 in the width direction is averaged by a reference thickness t, which is the thickness of the middle part of the thermal insulation layer 2 in the width direction W, the porosity at the peripheral part of the thermal insulation layer 2 is selected smaller than the porosity in the middle part. The number of fixed points bound by the substrate 1 in the peripheral of the thermal insulation layer 2 is increased by selecting the smaller porosity of the peripheral part of the thermal insulation layer 2 and the positions are dispersed, then the compression stress concentrated on the peripheral of the thermal insulation layer 2 can be dispersed. COPYRIGHT: (C)2006,JPO&NCIPI |
