| 摘要 |
PURPOSE:To prevent the deterioration of a tomographic image by multiple reflection, by connecting all of the piezoelectric elements other than ones being in a transmitting or receiving state of a piezoelectric vibrator group or the piezoelectric vibrators receiving a reflection signal thereof to an electrical matching circuit. CONSTITUTION:The drive pulse generated from a transmitter 3 is applied to the predetermined adjacent piezoelectric vibrator groups of a linear array piezoelectric vibrator group (LA) 504 constituting a variable delay apparatus 202 through a selection switch 204 selecting a predetermined vibrator group of LA 504. The variable delay apparatus 202 has the vibrators of the LA 504 and the selection switches 501 respectively corresponding thereto. All of the selection switches 501 not relating to transmission or reception are connected to b-terminals, that is, an electrical matching circuit 503 and a multiple reflected ultrasonic beams are converted to electric signals as many as possible to effectively lower the multiple reflected ultrasonic beams, that is, multiple reflection signals. |
