Datasheet
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S15E.pdf
08.10.31
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Construction and Operation Principles
1. Open Structure Type Ultrasonic Sensors
When voltage is applied to piezoelectric ceramics,
mechanical distortion is generated according to the volt-
age and frequency.
On the other hand, when vibration is applied to piezo-
electric ceramics, an electric charge is produced.
By applying this principle, when an electric signal is
added to a vibrator, constructed of 2 sheets of piezoelec-
tric ceramics or a sheet of piezoelectric ceramics and
a metal sheet, an electric signal is radiated by flexure
vibration. As a reverse effect, when an ultrasonic vibra-
tion is added to the vibrator, an electric signal is pro-
duced.
Because of these effects, piezoelectric ceramics are uti-
lized as ultrasonic sensors.
As shown in the diagram of an ultrasonic sensor (Fig. 2),
a multiple vibrator is fixed elastically to the base.
This multiple vibrator is a combination of a resonator
and a vibrator which is composed of a metal sheet and a
piezoelectric ceramics sheet. The resonator is conical in
order to efficiently radiate the ultrasonic waves gener-
ated by the vibration and also in order to effectively con-
centrate the ultrasonic waves at the central part of the
vibrator.
Fig. 3 shows a finite element method simulation of the
vibration of the multiple vibrators.
Case
Horn
Metal Plate
Piezoelectric
Ceramics
Base
Lead Terminal
Fig.2 Construction of Open Structure Type Ultrasonic Sensor
Cross Section of Half Side
Fig.3 Simulation of Vibration