Ultrasonic transducer element chip, probe, electronic apparatus, and ultrasonic diagnostic device

PROBLEM TO BE SOLVED: To provide an ultrasonic transducer element chip that is thin and has strength to withstand pressing force in a thickness direction of a substrate.SOLUTION: Openings are disposed in an array on a substrate. Ultrasonic transducer elements are provided to the respective openings on a first surface of the substrate. A reinforcement member 52 is fixed to a second surface of the substrate opposite to the first surface. Grooves 53 are formed on a surface of the reinforcement member 52. The grooves 53 are disposed at an interval L smaller than opening width S.SELECTED DRAWING: Figure 5