JPS63293462A - Ultrasonic device - Google Patents

Abstract

PURPOSE:To obtain pieces of phase information which are orthogonal to each other by dividing a transducer for reception into plural parts and allowing them to function acoustically independently of one another. CONSTITUTION:A transducer Tin functions as a transmitting electrode and is driven with an electric signal Si. Further, transducers Tout1 and Tout2 function as receiving electrodes and radiate ultrasonic longitudinal wave beams in liquid L toward a body to be inspected. The beams are propagated in the liquid L to reach the body 4 to be inspected and they are reflected partially by the surface of the body 4 to be inspected while the remainders are reflected by traveling inward. The reflected acoustic longitudinal wave beams are incident on the transducers Tout1 and Tout2 through the liquid L again and converted into electric signals S01 and S02 containing the pieces of phase information which cross each other at right angles. Here, the signals S01 and S02 of nearly the same time are led out of the transducers Tout1 and Tout2 unless elastic anisotropy is present at the reflection points of the ultrasonic wave beams and their peripheries. Therefore, the pieces of phase information which are orthogonal to each other are obtained.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an ultrasonic device that emits an ultrasonic beam toward an object to obtain acoustic information about the surface of the object and the state of its vicinity. Regarding equipment.

(Prior Art) Conventionally, there has been an ultrasonic device that generates ultrasonic waves to observe the surface and interior of an object, such as that disclosed in Japanese Patent Application No. 58-22978. FIG. 2 shows such an ultrasonic device. That is, on one plane of the piezoelectric plate 1, there are one arcuate transducer T Ill and T.

ut is arranged in such a way that one circle is divided into two. Transducers T in and T. ut is a pair of blind electrodes 2a, 2b; 3a, which are arranged concentrically, respectively;
3b. Transducer T. serves as an electrode for transmitting ultrasound beams. Transducer T. ut functions as an electrode that receives reflected waves of the ultrasound beam.

The piezoelectric plate 1 is connected to a transducer T, as shown in FIG. 3, in order to function as an ultrasound device.

It is placed so that it is immersed in liquid L (for example, pure water) with the side on which it is provided facing down. Furthermore, a subject 4 is placed at a position in the liquid that opposes the piezoelectric plate 1 .

A piezoelectric plate 1 is attached to the interdigital electrode of the transducer T in.
An electric signal Si in the radio frequency range is applied from a signal source (not shown), which is determined by the electrode period and the period of the electrodes. As a result, as shown by the arrows in FIG.
(0×θ1<90°, 0<θ2<90″), a longitudinal ultrasonic beam is emitted into the liquid. This ultrasonic beam propagates through the liquid and reaches the subject 4. Some of it is reflected by the surface of the object 4 (dotted line), and the rest travels inside and is reflected (solid line).The reflected longitudinal wave waves are again passed through the liquid to the transducer T.U. .

is input into the electrical signal S. is converted to

The transducer T, as long as there is no elastic anisotropy at and near the reflection point. and T. Since ut has a confocal point on the central axis of its circle, the transducer T. The electric signal S is detected from ut. It is closed and taken out. electrical signal S
. is a signal delayed from the electrical signal S, and if there is elastic anisotropy on the surface or inside of the object 4 irradiated with the ultrasound beam, the propagation speed of the sound wave will change, and the This causes changes in amplitude and phase difference. Therefore,
An electrical signal S having this amplitude and phase difference. When signal analysis is performed on the object, it becomes possible to detect cracks on the surface of the object and in its vicinity.

(Problem to be Solved by the Invention) However, according to the conventional ultrasonic device having such a configuration, there is only one transducer that receives the transmitted ultrasonic beam. There is a problem in that even if the object is scanned with a beam, only a single amplitude information and a single phase information can be obtained from a single receiving transducer.

This invention was made with the aim of solving the problems of the conventional techniques as described above, and provides an ultrasonic device that can obtain sufficient information about an object to be examined. The purpose is to

(Means for Solving the Problems) The ultrasonic device of the present invention includes a transmitting transducer and a receiving transducer arranged in an arc shape on one plane of a piezoelectric plate. , the ultrasonic beam of the transmitting transducer is emitted to the subject, and the ultrasonic beam reflected from the subject is received by the receiving transducer to obtain acoustic information about the subject. The receiving transducer is divided into seven parts, each of which functions acoustically independently.

(Function) According to this invention, since it is configured as described above,
Each receiving transducer functions acoustically independently and provides detection outputs that are orthogonal to each other.

(Embodiment) FIG. 1 is a plan view showing an embodiment of the present invention. On one plane of the piezoelectric plate 1, an arc-shaped transducer T i
n s T Ou L l and T 0ut2 are arranged in a format that divides one circle into three. The transducers T inb Toutl and T out2 have aperture angles α, β and β (where α>2β), respectively;
Three pairs of blind electrodes 5a, 5b arranged on concentric circles; 6
It has a; 6b; 7a, 7b. Transducer Ti
n is the one that functions as a transmitting electrode, and the electrical signal SI
Driven by. Transducer T. utl and T
. ut2 functions acoustically independently as receiving electrodes, and outputs electrical signals Sol and So2.

Next, the operation of such a configuration will be explained with reference to FIG. In the illustrated state, the piezoelectric plate 1 is a transducer T.

, T outl and T. It is assumed that ut2 is immersed in liquid L (for example, pure water) with the surface on which it is provided facing down. Further, a subject 4 is placed at a position in the liquid that opposes the piezoelectric plate 1 .

The blind electrodes 5a and 5b of the transducer TIn include
An electrical signal S determined by the piezoelectric plate 1 and the electrode period and in a frequency range below radio frequency, for example loOMIIz
, is applied from a signal source not shown.

As a result, from the transducer T in toward the subject 4, the angle θ (0° θ<90°
) emits a longitudinal ultrasonic beam into the liquid.

This ultrasonic beam propagates through the liquid and reaches the subject 4, a portion of which is reflected by the surface of the subject 4, and the rest of which travels inside and is reflected. Each reflected longitudinal sound beam is again passed through the liquid to the transducer T. utl and T. Electrical signals Sol and S are input to ut2 and include mutually orthogonal phase information. Converted to 2.

Here, unless there is elastic anisotropy at the reflection point of the ultrasound beam and its vicinity, the transducer T inb To
utl and T. Since uL2 has a confocal point on the central axis of its circle, transducer T. utl and T out
2, the electrical signals Sol and S have almost the same delay time. 2
is taken out.

However, if elastic anisotropy exists at the reflection point and its vicinity, the propagation between the ultrasound beam reflected on the surface of the object 4 and the longitudinal sound beam that travels inside and is reflected. The time difference increases. Correspondingly, the electric signal S. , and Sn2 also have a large difference from each other.

Electrical signal S. , and S. 2 has such properties, for example, the surface of the subject 4 is transduced by the transducer T. The transducer T is scanned by an ultrasonic beam. ut
l and T. Electrical signal S received by ut2. , and S. 2 is gated by a gate circuit, and held for a predetermined time by a sample-and-hold circuit, and signal analysis is performed for the amplitude and phase difference between the two, thereby obtaining information related to the subject 4, for example, the subject 4. It becomes possible to detect internal scratches and create three-dimensional images showing the shape of the surface.

In addition, when using a leaky Rayleigh wave as an ultrasonic beam, the thickness of the piezoelectric plate 1 is configured to be thicker than its electrode synchronization length, and the piezoelectric plate 1 is arranged so that the surface having the electrodes is in contact with the liquid stream. Place. However, when using a leaky Lamb wave, the piezoelectric plate 1 may be arranged so that the plate thickness is thinner than its period length and the surface opposite to the electrode surface is in contact with the liquid reservoir.

(Effects of the Invention) As explained in detail above, with the above configuration, each receiving transducer functions acoustically independently, and therefore mutually orthogonal phase information can be obtained. , more detailed information about the subject can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an ultrasonic device according to an embodiment of the present invention, FIG. 2 is a plan view of a conventional ultrasonic device, and FIGS.
The figure is a path diagram of an ultrasonic beam of an ultrasonic device. 1...Piezoelectric plate, T inn T outl+ T outl"" transducer.

Claims (1)

[Scope of Claims] A transmitting transducer and a receiving transducer are arranged in an arc shape on one plane of a piezoelectric plate, and an ultrasonic beam from the transmitting transducer is emitted to a subject. , an ultrasonic device configured to obtain acoustic information about the subject by receiving an ultrasound beam reflected from the subject by the receiving transducer, wherein the receiving transducer is divided into a plurality of parts. , an ultrasonic device characterized in that each of them functions acoustically independently.