US Patent 10426507 Ultrasonic surgical instruments

A surgical instrument including a transducer and an end effector is disclosed. The transducer may be configured to generate an acoustic standing wave of vibratory motion along a longitudinal axis and may include a piezoelectric stack positioned along the longitudinal axis. A length of the transducer may be less than ½ of the wavelength of the acoustic standing wave. The end effector may be acoustically coupled to and may extend distally from the transducer along the longitudinal axis. A sum of the length of the transducer and a length of the end effector may be an integer multiple of ½ of the wavelength of the acoustic standing wave.