JPS63308557A - Ultrasonic microscope - Google Patents

Abstract

PURPOSE:To enable independent detection of ultrasonic beams orthogonal to each other, by providing an ultrasonic device with two receiving transducers. CONSTITUTION:A high frequency pulse signal is applied to transducers Ti1 and Ti2 to emit an ultrasonic beam, which is converged with an acoustic lens 3 and reaches an object 2 to be inspected through a liquid L by Snell's law to be reflected on the surface of the object 2 being inspected. The ultrasonic beams of the transducers Ti1 and Ti2 contain components orthogonal to each other: when the object 2 being inspected has elastic anisotropy owing to a flaw, a clear phase difference appears in the ultrasonic beam reflected. Thus, the reflected ultrasonic wave is converted into electrical signals with two receiving transducers T<01> and T02 and can be detected as independent output.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an ultrasonic device that obtains information about the state of a subject by means of an ultrasonic beam emitted toward the subject, and in particular, The present invention relates to an ultrasonic microscope that independently receives mutually orthogonal components included in an ultrasonic beam.

(Prior Art) Conventionally, there is an ultrasonic device that emits an ultrasonic beam toward a subject to observe the surface and interior of the subject, for example, as disclosed in Japanese Patent Application No. 58-22978. Ta. FIG. 2 shows such an ultrasonic device. That is, fan-shaped transducers T in and T are arranged on one plane of the piezoelectric plate B. ut is arranged in such a way that one circle is divided into two. Here, the transducer T in functions as an electrode that transmits an ultrasound beam according to the applied electrical signal, and the transducer T in functions as an electrode that transmits an ultrasound beam according to an applied electrical signal. ut functions as an electrode that receives reflected waves from the ultrasonic beam emitted from the transducer T, □ and converts them into electrical signals.

In operation, the piezoelectric plate B acts as a transducer T, as shown in FIG. 2, 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, the subject 2 is placed in the liquid at a position facing the piezoelectric plate B and where the ultrasonic beam is focused.

An electric signal in the radio frequency range, which is determined by the piezoelectric plate B and the electrode period, is applied to the transducer T in from a signal source (not shown). As a result, as shown by arrows in FIG. 2, the angles θ1, θ2 (0〈θ1〈90°
, 0<θ2<90°), a longitudinal ultrasonic beam is emitted to the liquid. This ultrasonic beam propagates through the liquid and reaches the subject 2, a part of which is reflected by the surface of the subject 2 (dotted line), and the rest of it travels inside and is reflected (solid line). The reflected longitudinal ultrasound beam passes through the liquid again to the transducer T. ut and is converted into an electrical signal.

As long as there is no elastic anisotropy at and near the reflection point, the transducers T in and T. Since ut has a confocal point on the central axis of its circle, the transducer T,. The ultrasonic beam is detected by the transducer T out and extracted as an electrical signal. If elastic anisotropy exists on the surface or inside of the object 2, the propagation speed of the ultrasonic beam will change, and a corresponding amplitude change or phase difference will occur in the delayed electrical signal. Therefore, by signal analysis of the electric signal of the ultrasonic beam having such an amplitude and phase difference, it is possible to detect the surface and internal conditions of the object 2, such as cracks inside and outside the object 2.

(Problems to be Solved by the Invention) However, according to the conventional ultrasonic device having such a configuration, there is only one transducer for receiving an ultrasonic beam, so the ultrasonic wave of such a receiving transducer is Even if a subject is scanned with a sound beam, the ultrasound beams that are orthogonal to each other reflected from the subject cannot be detected independently, so there is a problem in that they cannot be distinguished.

This invention was made with the aim of solving the problems of the conventional technology as described above, and it is possible to independently detect ultrasonic beams that are orthogonal to each other from reflected ultrasonic beams. The purpose is to provide an ultrasonic microscope that can perform

(Means for Solving the Problems) The ultrasound microscope of the present invention includes transducers for transmitting ultrasound beams and transducers for receiving ultrasound beams, each of which is arranged in a fan shape on one plane of a piezoelectric plate. , the ultrasonic beam of the transmitting transducer is emitted to the subject, the ultrasonic beam reflected from the subject is received by the receiving transducer, and a detection signal representing the state of the subject is detected. At the same time, a plurality of the receiving transducers are provided, each of which is divided and arranged so as to be able to independently detect mutually orthogonal ultrasound beams among the ultrasound beams reflected from the subject. It is something that

(Operation) According to this invention, since it is configured as described above,
The two reception transducers independently detect ultrasound beams having signal components of corresponding phases, convert them into electrical signals for the following signal processing, and output them.

(Embodiment) FIG. 1 is a perspective view showing an embodiment of the present invention. The transducer section 1 functions as a piezoelectric device, and a ZnO piezoelectric thin film is sandwiched between thin film electrodes. This transducer section includes transducers Tit and Ti2 that have a function of emitting ultrasonic beams, and a transducer T that has a function of receiving ultrasonic beams. 1 and T. It is formed from 2.

Transducers Tit, Ti2, TO+ and T. 2 are arranged in the form of dividing one circle into four. The transducer section 1 is mounted on a flat first surface (-face in the illustrated position) of an acoustic lens 3 made of sapphire. The second surface (lower surface in the illustrated 1'7 position) of the acoustic lens 3 that opposes the first surface is a concave surface, and focuses the ultrasound beams emitted from the transducers T10 and T12, respectively. The subject 2 is placed at the convergence point of the acoustic lens 3 via the liquid from the second surface of the acoustic lens 3 .

Next, the operation will be explained. A pulse voltage is applied to the transducers T1□ and Ti2 of the transducer section 1 from a pulse generation source (not shown). In this case,
Transducer T'++ and transducer T12
Impulses or RF pulse signals having the same carrier frequency are simultaneously applied to the two. As a result, ultrasonic beams are emitted from the transducers Til and Ti2, are focused by the acoustic lens 3, and reach the subject 2 via the liquid according to Snell's law. In the subject 2, a part of the light is directly reflected on the surface of the subject 2, and the other part travels inside and is reflected. Here, transducer T1. The ultrasonic beam of the transducer T and the ultrasonic beam of the transducer T, 2 contain mutually orthogonal components, but unless the object 2 has elastic anisotropy due to scratches, there is almost no phase difference between them. does not occur. However, if the subject 2 has elastic anisotropy due to scratches or the like, a clear phase difference will appear in the reflected ultrasound beam. Thereby, the subject 2 can be captured as a distribution of elastic anisotropy.

In the vicinity of the surface layer of the object 2, the transducer Til,
Two ultrasound beams emitted from Ti2 pass through the transducer T1. When the electric signal applied to the test object 2 is a high-amplitude continuous wave, the nonlinear component of the object 2 is emphasized. These reflected ultrasound beams reach the transducer T via the reverse path as described above. , and T. 2. Therefore, the transducer T. I and T. 2
The converters independently convert the ultrasonic beams incident through the paths shown in the arrow directions into electrical signals and output the electrical signals.

Since these electrical signals also include a frequency component twice that of the carrier wave, only this twice the frequency component can be extracted by the filter. In this way, the subject 2
The electrical signal detected in relation to the subject 2 is processed by ordinary signal processing means such as a phase comparator.
A phase difference containing state information is detected. In addition, subject 2
In order to obtain a two-dimensional display representing the state of the subject 2,
The object 2 may be scanned by sequentially shifting the position of the ultrasonic beam arriving at the object 2 using known appropriate means, thereby continuously detecting electrical signals representing phase differences.

FIG. 4 is a plan view of a microscope according to another embodiment of the invention. In this case, one transmitting transducer T
Two transducers T for i+. , and T. 2
will be provided. Transducers To1 and T. 2 is
Ultrasonic beams reflected by the subject 2 through the paths shown by the arrows in the figure and containing mutually orthogonal components can be detected independently.

(Effects of the Invention) As explained below, the present invention is capable of allowing two receiving transducers to independently receive orthogonal components of the ultrasound beam reflected from the subject. As a result, an ultrasonic beam containing phase information that can be displayed two-dimensionally can be obtained, and even minute changes in the object can be accurately detected. Since orthogonal ultrasound beams can be received separately without the need for a coupler, the device can be simplified.

[Brief explanation of drawings]

FIG. 1 is a plan view of a transducer for an ultrasound microscope according to an embodiment of the present invention, FIG. 2 is a path diagram of an ultrasound beam by a conventional ultrasound device, and FIG. 3 is a plan view of a transducer for an ultrasound microscope according to an embodiment of the present invention. FIG. 4 is a plan view of a microscope transducer according to another embodiment of the present invention. 1a...Transducer section, T12, Ti2, Tol, To2...Transducer. Expression convex momi 艮 beam tl red language Vη Book 3 diagram ko + feliMiff! aaMmD>2iu,-”j
rmm qin 4 figure

Claims (1)

[Scope of Claims] A transducer for transmitting an ultrasonic beam and a transducer for receiving an ultrasonic beam are arranged in a fan shape on one plane of a piezoelectric plate, and the ultrasonic beam of the transmitting transducer is emitted to a subject; In the ultrasound microscope, the ultrasonic beam reflected from the subject is received by the receiving transducer to obtain a detection signal representing the state of the subject, wherein a plurality of the receiving transducers are provided, and each of the receiving transducers is provided with a detection signal representing a state of the subject. An ultrasound microscope characterized in that the ultrasound microscope is arranged to independently receive ultrasound beams orthogonal to each other among ultrasound beams reflected from a subject.