ULTRASONIC WAVE TRANSDUCER AND MANUFACTURING METHOD FOR THE SAME

To make it easy to adjust the resonance frequency.SOLUTION: An ultrasonic transducer includes a plurality of elements including: a substrate 10 where a gap 13 is provided from an upper surface side toward a lower layer, a lower electrode 12 provided so as to cover the substrate and the gap, a piezoelectric layer 14 provided so as to cover the lower electrode, an upper electrode 16 provided so as to cover the piezoelectric layer in a first region 51, which is a central region of the gap in a plan view, and not provided on the piezoelectric layer in a second region 52, which is a peripheral region of the gap in a plan view, and a protection film provided so as to cover the upper electrode and the piezoelectric layer in the second region. The elements include a first element in which the thickness of the protection film in the first region is thinner than the thickness of the protection film in the second region, and a second element in which the thickness of the protection film in the second region is thinner than the thickness of the protection film in the first region.SELECTED DRAWING: Figure 13 【課題】共振周波数の調整を容易にすること。【解決手段】超音波トランスデューサは、上面側から下層に向けて空隙１３が設けられた基板１０と、前記基板および前記空隙を覆うように設けられた下部電極１２と、前記下部電極を覆うように設けられた圧電層１４と、平面視における前記空隙の中央領域である第１領域５１の前記圧電層を覆うように設けられ平面視における前記空隙の周縁領域である第２領域５２の前記圧電層上に設けられていない上部電極１６と、前記上部電極および前記第２領域における前記圧電層を覆うように設けられた保護膜と、を備える素子が複数設けられ、前記複数の素子は、前記第１領域の前記保護膜の厚さが前記第２領域の前記保護膜の厚さより薄い第１素子と、前記第２領域の前記保護膜の厚さが前記第１領域の前記保護膜の厚さより薄い第２素子と、を含む。【選択図】図１３