JPH0448080Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to the structure of an ultrasonic transmitter/receiver.

As an example of an ultrasonic transmitter/receiver device, Japanese Patent Publication No. 51-23341,
There is Utility Model No. 55-162487.

All of these devices utilize only flat equalizers.

An ultra-flat ultrasonic transmitter/receiver device having an equalizer in the center of a front plate 18 with fixing holes 19 on the outer periphery is shown in FIG.
A diagram of the plane taken vertically at 0 is shown.

A driving ceramic plate 12 is bonded to the back of the diaphragm, and a housing 14 with lead terminals 13 is attached to the back, while a flat equalizer 15 is arranged on the front.

Now, in this case, when an electrical excitation signal is applied to the ceramic plate 12, the frequency F of the ultrasonic vibration that can be used most effectively is as shown in the model in FIG. 3a. Where, t: Thickness of plate (cm) R: Radius of disk (cm) ρ: Density (g/cm ³ ) α: Poisson's ratio Q: Young's modulus (dyne/cm ² ) K: Frequency of upper tone The constant is 3.91, and the vibration model is a solid line in the case of a positive (+) signal, and a dotted line in the case of a negative (-) signal.

Ideally, if the air near the center is radiated to the front by this vibration, as shown by the arrow 21 in Figure b, the ultrasonic transmitter/receiver will be very efficient. As shown in the cross-sectional view of Figure 2a, in a typical flat equalizer, the air near the center flows very easily to the periphery where it vibrates in the opposite direction, as shown by the broken line arrow 22, and is not effective. Ultrasonic signals cannot be emitted in the front direction.

In this situation, the vibration around the diaphragm, that is, the vibration energy shown by the arrow 23 is consumed as shown by the arrow 24, resulting in energy loss and not enough effective vibration energy 23 being obtained.

This state is shown in FIGS. 3b and 3c, and the state of the node ring 25 of the diaphragm is shown in a plan view in FIG. 3d.

If the diaphragm 11 is uniform, approximately √2/R
Although the joint ring 25 can be seen at a certain position, as shown in the figure, it may be deviated in the inner and outer directions due to the influence of the adhesion of the ceramic plate.

As shown in Fig. 1, the diaphragm 11 and the equalizer 15
If the air in the gap 16 freely flows in the opposite phase direction along the surface of the diaphragm, ultrasonic vibrations cannot be emitted in any effective direction.

For this reason, in order to prevent the air on the surface of the diaphragm from flowing from the inside to the outside of the joint ring 25 or from the outside to the inside, a cylinder made of polymeric resin 20, Different diameter cylinders, discs, or
The equalizer was changed from a flat shape to a part of it, the surface of the diaphragm, and the polymer resin 2.
A cross-sectional view of what is bonded using 0 is shown.

In addition, in these figures, the vibration energy 21 on the outer circumference of the node ring suppresses the energy in the opening, in other words, the energy flowing from the outer circumference to the inner circumference is suppressed, and the center is opened. If the front plate is designed to have holes, the idea of the present invention can be applied.

It is characterized in that the loss energy 22 flowing along the surface of the diaphragm is blocked by the polymer resin 20, and the energy 23 effectively radiated to the front from the predetermined openings 17 is increased. The ultrasonic transceiver device of the present invention is expected to be used in a wide range of fields and has industrial value.

[Brief explanation of the drawing]

FIG. 1 shows a typical example of an ultrasonic transmitter/receiver, in which a is a sectional view and b is a front view. Figure 2a shows the conventional equalizer 15 and diaphragm 11, and b, c, d, e, f, g, and h show a polymer resin 20 installed in the gap between the equalizer 15 and diaphragm 11 of the present invention. Each state is shown in a longitudinal cross-sectional view. FIG. 3a shows the vibration mode of a diaphragm whose periphery is fixed, and b and c show the loss energy as a model. d shows a front view of the vibration node ring. Number 11 is a diaphragm, 12 is a ceramic drive plate, 14 is a housing, 15 is an equalizer 17 is an opening, 18 is a front plate, 20 is an attachment made of resin, 21 is a center 22 is loss energy, 23 is energy at outer periphery, 24 is loss energy, 25 is
It is a vibrational nodal ring.

Claims (1)

[Scope of utility model registration request] An equalizer to be placed on the front of the diaphragm is attached to the nodal part of the diaphragm using polymeric resin in the gap between the diaphragm and the equalizer, and the equalizer is placed on the front of the diaphragm from the center to the outer periphery (from the outer periphery to the center). A structure of an ultrasonic transmitting/receiving device characterized by controlling loss energy flowing into the body.