JPH05107234A - Method and device for inspecting ultrasonic probe - Google Patents

Abstract

PURPOSE:To provide a detection device of an ultrasonic probe for high frequency which is used for an ultrasonic microscope, etc., which can be evaluated easily and accurately. CONSTITUTION:An ultrasonic probe 4 is scanned within an XY plane while it is defocused for a pole target 6, a signal is received by a transmission means 1 and a reception means 7, and then a change in the intensity of the reception signal is detected by detection means 8 and 9. A symmetric property of an ultrasonic beam can be judged according to that of the signal intensity change.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection method and an inspection apparatus for an ultrasonic probe used in an ultrasonic microscope or the like,
In particular, the symmetry of the ultrasonic beam, which is important in evaluating the performance of the probe, can be inspected.

[0002]

2. Description of the Related Art FIG. 14 is a diagram for explaining a conventional method for evaluating a focused ultrasonic probe. First, the focusing type ultrasonic probe will be described. In this type of ultrasonic probe, as shown in FIG. 14A, a lower electrode 4c is formed on the upper surface of the acoustic lens 4d, and the lower electrode 4c is formed on the acoustic lens 4d. The piezoelectric element 4b and the upper electrode 4a are sequentially arranged in the
A voltage is applied to a and 4c to excite the piezoelectric element 4b, the generated ultrasonic waves are focused by the concave portion 4e formed on the lower surface of the acoustic lens 4d and transmitted to the sample (target), and the reflected wave is also detected. It is configured so that it can be converted into an electric signal and taken out by a tentacle.

In this case, since ultrasonic waves are substantially generated only in the portions where the lower electrode 4c, the piezoelectric element 4b and the upper electrode 4a all overlap, the central axes of the piezoelectric element 4b and the upper electrode 4a are Acoustic lens 4d (recess 4
It is necessary that the sound axis of the ultrasonic beam propagating in the acoustic lens 4d and the central axis of the acoustic lens 4d (concave lens) match exactly with the central axis of e). If the sound axis and the central axis do not match, the ultrasonic transmission beam focused by the acoustic lens 4d is emitted asymmetrically, and the reflected wave incident on the probe 4 is also received asymmetrically. Will be. Therefore, whether or not the sound axis of the ultrasonic beam propagating in the acoustic lens 4d coincides with the central axis of the acoustic lens 4d, in other words, the ultrasonic beam is generated symmetrically with respect to the central axis of the acoustic lens 4d. Whether or not the probe 4 is an important evaluation target of the performance of the probe 4.

Returning to FIG. 14, the illustrated conventional example uses a ball target as a target. The ball target is a ball 20 made of a spherical steel ball having a diameter D, and is supported by a fixed base 19 via a column 21 as shown in FIG. 2A, or as shown in FIG. It is used by being fixed directly.

Now, the probe 4 and the ball 20 set in the ultrasonic inspection apparatus are arranged side by side in the vertical direction.
The focal point of the ultrasonic wave generated by is set on the surface of the ball 20. In this state, when the probe 4 is scanned in one horizontal direction to detect the signal intensity of the reflected wave SB, the envelope of the reflected wave SB as shown in FIG. The symmetry between the ultrasonic beam and the acoustic lens 4d can be evaluated based on whether or not this envelope is bilaterally symmetric with respect to the peak value.

Alternatively, similar scanning is performed in two horizontal directions orthogonal to each other, and as shown in FIG. 14 (c), the half-value width of the envelope in each direction, that is, the signal intensity is half the peak value across the peak value. The distance d _-6 between the two points (that is, -6 dB from the peak value) is calculated. This half-value width (referred to as beam diameter) d _-6 is theoretically expressed by the following equation, but the symmetry is evaluated by whether or not the values actually measured in two orthogonal directions match. ..

[Equation 1] In the above equation, λ _w is the wavelength in the medium,
If the speed of sound in the medium is C _w and the frequency is f, then λ _w = C
It is represented by _w / f. Further, F is the focal length of the probe 4, and r is the opening radius of the recess 4e.

It is also possible to set the probe 4 in an ultrasonic microscope or the like, scan the ball target in the horizontal plane in the same manner, image the result, and evaluate whether the image is a circle or not. Is. In addition, as another general method for evaluating the performance of the probe, multiple types of diffraction grating-like samples with multiple grooves (slits) of constant width are prepared by changing the width of the groove, and the top and bottom of the groove are prepared. There is a method in which the resolution is evaluated by the minimum groove width at which the and can be separated.

[0008]

However, in the inspection of the ultrasonic probe using the conventional ball target as described above, the diameter D of the ball 20 required for measurement is the beam diameter d _-6 . Because of the same degree, there was a problem that many ball targets had to be prepared according to the beam diameter of the probe to be inspected.

Further, in the probe 4 for the ultrasonic microscope used in the high frequency band of 100 MHz to 1 to 2 GHz, the beam diameter d _-6 is about 30 to 1 μm, so the diameter of the ball 20 is also about 30 to 1 μm. However, if the ball is so small, it is difficult to obtain a true sphere, and as shown in FIG. 14 (a), a column 21 for supporting the ball 20 is attached to the fixing base 19. There was a problem that it would be extremely difficult to install. On the other hand, as shown in FIG. 2B, when the ball 20 is directly fixed to the fixed base 19, the reflected wave SP from the surface of the fixed base 19 and the reflected wave SB from the ball 20 interfere with each other, and There is a problem that the envelope shown in) cannot be obtained.

The method using a sample provided with a slit is for checking the resolution, and it is directly determined whether the sound axis of the ultrasonic wave generated by the transducer and the central axis of the acoustic lens are coincident with each other. It is difficult to make a positive judgment.

An object of the present invention is to provide an ultrasonic probe inspection apparatus capable of easily and accurately evaluating a high-frequency probe used in an ultrasonic microscope or the like.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1 showing an embodiment, the present invention will be described with reference to an ultrasonic probe for evaluating the symmetry of an ultrasonic beam transmitted from an ultrasonic probe 4. It is applied to the inspection method and inspection device for the child 4. The invention according to claim 1 is directed to a target 6 having a convex curved surface whose cross section is at least partly axially symmetrical with respect to at least one axis, and the direct reflected wave from this target 6 and other reflected waves are The ultrasonic probe 4 is attached to the target 6 so as to interfere with each other when received by the ultrasonic probe 4.
Of transmitting and receiving ultrasonic waves between the ultrasonic probe 4 and the target 6 while relatively moving in a direction orthogonal to the axis of And a step of outputting a change in signal intensity corresponding to the position of the ultrasonic probe 4 when the received signal is obtained, and evaluating the symmetry of the ultrasonic beam from the symmetry of the change in signal intensity. By enabling it, the above-mentioned object is achieved. The invention according to claim 2 is an apparatus for carrying out the method for inspecting an ultrasonic probe according to claim 1,
A target 6 having a convex curved surface whose cross section is at least partly axially symmetric with respect to one axis, and a focus position of the probe 4 crosses the target 6 and the axis, and
A moving unit 11 that relatively moves the ultrasonic probe 4 in a direction orthogonal to the axis in the cross section, and a transmitting unit 1 that excites the ultrasonic probe 4 and transmits an ultrasonic wave. , Receiving means 7 for receiving a signal from the ultrasonic probe 4, and moving means 11 for moving the ultrasonic probe 4 to detect a change in the intensity of the signal received by the receiving means 7. The detection means 8 and 9 are provided.
Furthermore, the invention of claim 3 is the inspection apparatus according to claim 2, wherein the direct reflection wave of the target reflected by the surface of the target 6 by the transmitting means 1 and the receiving means 7 and the elastic surface from the target 6. It is like receiving an interference wave with a wave. The invention of claim 4 is the inspection apparatus according to claim 2, wherein the direct reflection wave of the target reflected by at least the surface of the target 6 by the transmitting means 1 and the receiving means 7 and the ultrasonic probe. It is like receiving an interference wave with the reflected wave inside the probe reflected at the tip interface of No. 4.

[0013]

The moving means 11 relatively moves the ultrasonic probe 4 so that the direct reflected wave from the target 6 and other reflected waves interfere with each other when received by the ultrasonic probe 4. When the signal is received by the receiving means 7 while being performed, the distance between the ultrasonic probe 4 and the target 6 changes symmetrically with respect to the axis, and as a result, the interference wave received by the receiving means 7 is changed. The intensity also changes. If the ultrasonic beam is symmetric, the change in the signal received by the receiving means 7 also appears symmetrically with respect to this axis, but if the ultrasonic beam is asymmetric, the change in the received signal also appears asymmetric. Therefore, if the detection means 8 and 9 detect a change in the intensity of the received signal, the symmetry of the ultrasonic beam can be determined from the symmetry of the change in the signal intensity.

Incidentally, in the section of means and action for solving the above problems for explaining the constitution of the present invention, the drawings of the embodiments are used for the purpose of making the present invention easy to understand. It is not limited to.

[0015]

【Example】

-First Embodiment- A first embodiment of the present invention will be described with reference to Figs. FIG. 1 is a block diagram showing the configuration of the inspection apparatus of this embodiment. In the figure, an oscillator 1 generates a pulse-shaped or pulse-shaped electric signal which is continuous for a predetermined time. This signal is applied to the upper electrode 4a and the lower electrode 4c of the probe 4 via the circulator 2 and the matching device 3, and ultrasonic waves are generated by the piezoelectric element 4b. This ultrasonic wave propagates through the acoustic lens 4d and the concave portion (concave lens) 4e on the lower surface thereof.
Are focused by and are transmitted into the medium (mainly water) 5 toward the target 6. The ultrasonic wave reflected by the target 6 follows a path opposite to the above, is received by the piezoelectric element 4b, is converted into an electric signal, and is extracted to the outside via the upper and lower electrodes 4a, 4c. The extracted reception signal is amplified by the receiver 7 via the matching unit 3 and the circulator 2, the peak value is detected by the peak detector 8, and a DC voltage proportional to the peak value is output. The detected peak value is converted into a digital value by the microcomputer 9 and taken in.

The microcomputer 9 also scans the XYZ scanner 11 on which the target 6 is placed via the XYZ controller 10, and sets the above-mentioned peak value to the position of the XYZ scanner 11 on the X, Y, Z coordinates at that time. The image is stored in the image memory 12 in correspondence with the monitor (2)
The image is displayed on 13a in real time. The scanning range, coordinates and the like are displayed on the monitor (1) 13b, and the setting values and the like are input from the keyboard 14. Image measurement unit 1
5 analyzes and evaluates the measurement result, which will be described in detail later. The oscilloscope 16 monitors the gate for detecting the peak value of the reflected wave from the target 6 with the peak detector 8.

In the correspondence between the scope of the claims and the embodiment, the oscillator 1 constitutes the transmitting means, the receiver 7 constitutes the receiving means, and the peak detector 8 and the microcomputer 9 constitute the detecting means. In the following description, the Z axis is taken in the vertical direction, the X axis is in the horizontal direction extending in the left-right direction of the paper in FIG. 1, and the Y axis is in FIG.
It is taken horizontally through the paper.

In FIG. 2, the ultrasonic waves transmitted from the probe 4 are focused by the acoustic lens 4d (hereinafter referred to as a focal position, and the distance to the concave portion 4e of the acoustic lens 4d is called a focal length). FIG. 8 is a diagram when moving from the surface of the sample 17 in the −Z direction. If the surface acoustic wave velocity C _R propagating on the surface of the sample 17 is higher than the velocity C _{W of the} medium 5, the acoustic lens 4
The ultrasonic wave (solid line path) reflected by the surface of the sample 17 from the center of the concave portion 4e of d and the concave portion 4 of the acoustic lens 4d.
e An ultrasonic wave incident from the peripheral portion through the medium 5 at an angle ψ (= sin ⁻¹ C _W / C _R ) formed with the perpendicular to the surface of the sample 17 is sample 1.
The surface acoustic wave is generated on the surface 7 and the ultrasonic wave (path of the broken line) propagating through the acoustic lens 4d interferes again via the medium 5 at the angle ψ and is received by the probe 4. Therefore, the ultrasonic waves propagating through these two paths have a path difference (that is, a phase difference of the ultrasonic waves) depending on the positions of the probe 4 and the sample 17, and the received signal strength is different. As a result, as shown in FIG. 3, when the focus position of the probe 4 is the sample surface (Z = 0), the horizontal axis represents the distance in the −Z direction, and the vertical axis represents the signal intensity V, a constant period. It is known that a curve with is obtained. This curve is called a V (Z) curve.

The V (Z) curve is not obtained only when the probe 4 is brought close to the flat plate-shaped sample 17, but the concave lens of the probe 4 as shown in FIGS. 4 and 6 is obtained. Spherical ball target 6 having a diameter D sufficiently larger than the opening 2r
Can be similarly obtained by using. That is, as shown in FIG. 4, with respect to the ball target 6 having a diameter D (D> 2r), the focus position of the probe 4 is set on the central axis of the ball target 6.
Z ₁ from the surface of the (defocus only -Z ₁ )
In this state, when scanning in the X direction, for example, since the ball target 6 is a sphere, the probe 4 moves to the ball target 6
The distance to the surface of the sample changes, resulting in a flat sample 1.
The signal intensity of the reflected wave changes in the same manner as in the case of approaching in the Z-axis direction at 7.

As shown in FIG. 4, when the piezoelectric element 4b and the upper electrode 4a are formed concentrically with respect to the acoustic lens 4d, this change is caused by the Z axis between the surface of the ball target 6 and the Z axis. Although the distances in the directions change symmetrically, they appear symmetrically. However, as shown in FIGS. 6A and 6B, the central axis of the upper electrode 4a or the piezoelectric element 4b is deviated from the central axis of the acoustic lens 4d, Sound axis of generated ultrasonic wave and acoustic lens 4d
In the case of a defective probe whose center axis does not match, it appears asymmetrically. Therefore, by detecting the change in the signal intensity of the reflected wave, it is possible to inspect whether the sound axis of the ultrasonic wave generated by the probe 4 and the central axis of the acoustic lens match.

Now, the radius of the ball target 6 will be examined. Set the Z direction defocus amount of the probe 4 to −
Z ₁ , the scanning range in the XY plane, for example, the amount of movement of the probe in the X direction is shown in FIG. 9, where X is the center axis of the ball target 6 in the Z axis direction and the center axis passing through the scanning range end A. If the opening angle is θ, the radius R of the ball target 6 is expressed by the following equation.

[Equation 2]

Now, as an example, 100 MHz, opening angle 100 °,
FIG. 10 shows the result of measuring the V (Z) curve of quartz glass for the probe having a beam diameter of 14 μm. From this figure, the defocus amount of the probe 4 on the central axis of the ball target 6 is set to approximately -80 μm. Next, if the number of pixels of the monitor 13a is 400 × 400 dots and the measurement pitch is 2.5 μm,
The amount of movement of the probe in the X direction is X = 2.5 × 400 = 1000 μm. Further, the opening angle θ is set to 5 ° (empirical value). Substituting these numerical values into the equation 2 to obtain R gives R≈5.8 mm.

Next, FIG. 11 shows the result of measuring the V (Z) curve similarly for the probe having 200 MHz, the opening angle of 100 ° and the beam diameter of 7 μm. From this figure, the defocus amount of the probe 4 on the central axis of the ball target 6 is approximately −40.
μm. Also, the movement amount X of the probe in the X direction is the same as
1000 μm. Similarly, when the opening angle θ is 5 ° and R is calculated from the above equation, R≈5.8 mm. Thus, in the above equation, the value of the second term on the right side is usually sufficiently smaller than the value of the first term on the right side. Therefore, the second term on the right side is omitted and R =
If expressed in X / 2 tan θ, a common ball can be used.

Next, the operation of this embodiment will be described.
As described above, a ball target 6 made of steel having a diameter D (D> 2r) as shown in FIG. 4 is used as the target 6, and the probe 4 is mounted on the center axis of the ball target 6 from the surface of the ball target 6 by Z ₁ The signal intensity of the received reflected wave is displayed in the four gradations shown in FIG. 3 by scanning in the XY plane while keeping the distance reduced by only. When the probe 4 is a normal probe as shown in FIG. 4, the graphics represented by each gradation are concentric circular as shown in FIG. 5, and the center of gravity of each graphics is the same as one point O. To do.

On the other hand, in the case of the defective probe as shown in FIGS. 6 (a) and 6 (b), an image as shown in FIG. 7 is obtained, and the center of gravity of the graphic shown in each gradation is O ₀ ~O ₃ and is in do not match. Therefore, the quality of the probe is determined by calculating the center of gravity of the graphic represented by each gradation and the deviation of each center of gravity by the image measuring unit 16.

Specifically, the scanning range in the XY plane is X × Y = a × a (unit is mm), and the measurement pitch is P = b.
(Same), the number of pixels N × N = a / b × a / b. If the gradation on the screen is displayed by S (X, Y) (X, Y = 0 to 3), the center of gravity O _n (X _n , Y _n ) (n = 0) of the graphic of each gradation is displayed.
The coordinate values X _n and Y _n of 3 to 3) are calculated by the following equations.

[Equation 3] The positions of O _{0 to} O ₃ thus obtained are shown in FIG. Then, the distance Lm between these barycentric coordinates (m =
0-5) is calculated by the following equation. In the following equation, i = 0 to 3 and j = 1 to 3 (where i ≠ j).

[Equation 4]

The quality of the probe 4 is determined by whether or not the Lm thus obtained is within an allowable range that satisfies the required probe performance. Of course, FIG. 5 or FIG.
It is also possible to directly observe the image as shown in (1) on the monitor and directly judge the quality.

Thus, according to this embodiment, the upper electrode 4
The deviation of the central axis between the a or the piezoelectric element 4b and the acoustic lens 4d is shown as an image, which can be displayed / judged and recorded by both the image and the numerical value. In addition, the ball target 6 used for the target 6 has a size of mm unit, and it is easy to obtain a true sphere, and there is an advantage that production of the ball target 6 and positioning of the probe can be performed easily.

-Second Embodiment- A second embodiment of the present invention will be described with reference to FIGS. FIG. 12 is a diagram for explaining the principle of the inspection method and the inspection apparatus of this embodiment. The structure of the inspection device of this embodiment is the same as the inspection device of the above-mentioned first embodiment except the duration of the pulsed electric signal generated by the oscillator 1 and the duration of the ultrasonic wave generated by the piezoelectric element 4b. Therefore, the same components are designated by the same reference numerals to simplify the description.

Specifically, the duration of the pulsed electric signal generated by the oscillator 1 is determined by the acoustic lens 4 in FIG.
Echo R reflected at the interface of the concave portion (concave lens) 4e of d
_l and the direct reflection echo R _s reflected by the surface of the flat plate-shaped sample 17 are selected so as to interfere with each other when received by the piezoelectric element 4b. Such a condition can be realized by making the duration of the electric signal generated by the oscillator 1 sufficiently long, and conversely, in the above-described first embodiment, these echoes R _l and R _s interfere with each other. The duration of the electric signal is set to be short so that it will not occur. The condition for the echoes R _l and R _s to interfere with each other is that the distance from the concave lens 4e on the central axis of the probe 4 to the sample 17 is f _0.
(In FIG. 2, since the focal point of the ultrasonic beam is located on the surface of the sample 17, this distance is equal to the focal length), the sound velocity of the medium 5 is C _w , and the ultrasonic wave generated by the piezoelectric element 4b is Let T be the duration of

[Equation 5] Given in.

When an ultrasonic wave is generated under the condition given by the above equation, when the horizontal axis represents the distance in the -Z direction and the vertical axis represents the received signal strength, a constant period λ _w / 2 based on interference.
A curve having (λ _w is the longitudinal wave sound velocity of the medium 5) is obtained. Figure 12 shows a frequency of 440 MHz, an aperture angle of 100 °, and a beam diameter of 3.2.
It is a figure which shows the result of having measured the intensity | strength of the reflected wave from quartz glass based on the above-mentioned conditions about the probe of μm.
It can be seen that a curve in which both the interference between the sample surface wave and the direct reflection echo (period ΔZ) and the interference between the lens surface reflection echo and the direct reflection echo (period λ _w / 2) are obtained can be obtained. The interference between the lens surface reflection echo and the direct reflection echo can be obtained if the above conditions are satisfied regardless of the acoustic properties of the sample (for example, the presence or absence of surface waves).

The curve as shown in FIG. 12 is not obtained only when the probe 4 is brought close to the flat plate-like sample 17 as in the case of the above-described first embodiment. The same can be obtained by using a spherical ball target 6 having a diameter D sufficiently larger than the opening 2r of the concave lens of the probe 4 as shown in FIG. That is, as shown in FIG.
With respect to the ball target 6 of (D> 2r), the focal position of the probe 4 is lowered from the surface of the ball target 6 by Z ₁ (defocused by −Z ₁ ) on the central axis thereof.
For example, when scanning in the X direction, the distance from the probe 4 to the surface of the ball target 6 changes because the ball target 6 is a sphere, and as a result, when the planar sample 17 is brought closer to the Z axis direction. Similarly, the signal intensity of the reflected wave changes.

As shown in FIG. 4, when the piezoelectric element 4b and the upper electrode 4a are formed concentrically with respect to the acoustic lens 4d, this change is caused by the Z axis between the surface of the ball target 6 and the Z axis. Although the distances in the directions change symmetrically, they appear symmetrically. However, as shown in FIGS. 6A and 6B, the central axis of the upper electrode 4a or the piezoelectric element 4b is deviated from the central axis of the acoustic lens 4d, Sound axis of generated ultrasonic wave and acoustic lens 4d
In the case of a defective probe whose center axis does not match, it appears asymmetrically. Therefore, by detecting the change in the signal intensity of the reflected wave, it is possible to inspect whether the sound axis of the ultrasonic wave generated by the probe 4 and the central axis of the acoustic lens match.

With respect to the radius of the ball target 6, the same discussion as in the above-mentioned first embodiment is valid, and therefore its explanation is omitted. Now, as an example, the above-mentioned frequency of 440 MHz,
Considering a probe with an aperture angle of 100 ° and a beam diameter of 3.2 μm, the sound velocity of water (medium) is C _w = 1500 m / s.
_w = 3.4 μm and λ _w / 2 = 1.7 μm. Referring to FIG. 12, the above-mentioned defocus amount Z ₁ = 1.5 × (λ _w /2)≈2.6 μ
m. Next, the number of pixels of the monitor 13a is 400 × 400 dots, and the measurement pitch should be less than the beam diameter.
Since (beam diameter) / 2 is 1.6 μm, the moving amount of the probe in the X direction is X = 1.6 × 400 = 640 μm. Further, the opening angle θ is set to 5 ° (empirical value). Substituting these numerical values into Equation 2 to obtain R gives R≈3.7 mm.

Next, the operation of this embodiment will be described.
As described above, a ball target 6 made of steel having a diameter D (D> 2r) as shown in FIG. 4 is used as the target 6, and the probe 4 is mounted on the center axis of the ball target 6 from the surface of the ball target 6 by Z ₁ The signal intensity of the received reflected wave is displayed in four gradations shown in FIG. 12 by scanning in the XY plane while keeping the distance reduced by only. When the probe 4 is a normal probe as shown in FIG. 4, the figure represented by each gradation has a concentric annular shape as shown in FIG.
The center of gravity of each figure coincides with one point O.

On the other hand, in the case of the defective probe as shown in FIGS. 6 (a) and 6 (b), an image as shown in FIG. 7 is obtained, and the center of gravity of the graphic shown in each gradation is O ₀ ~O ₃ and is in do not match. Therefore, the quality of the probe is determined by calculating the center of gravity of the graphic represented by each gradation and the deviation of each center of gravity by the image measuring unit 16. The above procedure is the same as that of the first embodiment described above, and therefore detailed description thereof is omitted.

Therefore, also in this embodiment, the above-mentioned first
It is possible to obtain the same effect as that of the embodiment. In particular, this embodiment has an excellent effect that the performance of the probe, which is difficult to measure according to the first embodiment, can be evaluated. That is, in the inspection method and apparatus of the first embodiment, V obtained from the sample (ball target 6) is used.
Since the probe 4 is evaluated using the period ΔZ of the (Z) curve (curve A in FIG. 13), when the V (Z) curve cannot be obtained due to the relationship between the sample and the probe. Evaluation may be impossible. For example, a V (Z) curve is obtained for the probe 4 which is used for the purpose of internal flaw detection or the like, and in which the opening angle φ shown in FIG. 2 is sufficiently small and a surface acoustic wave does not occur on the surface of the sample 17. None (curve B in FIG. 13). Further, in the high frequency probe 4, since the radius of curvature of the concave lens 4e is small and the focal length is also short, the defocus amount cannot be large, and the defocus amount Z required for the evaluation of the probe 4 is small. ₁
Cannot be secured (curve C in FIG. 13). In the case of the probe shown by the curve B in FIG. 13, a V (Z) curve can be obtained by selecting a material having a high sound velocity (for example, ceramic) as the material of the target. The work of selecting the material is troublesome.

On the other hand, the inspection method and apparatus of this embodiment are
The probe 4 is evaluated using the interference period λ _w / 2, which is determined by the speed of sound of the medium, the distance between the acoustic lens 4d and the target 6 and the duration of ultrasonic waves, regardless of the acoustic properties of the target. Therefore, the symmetry of the ultrasonic beam can be evaluated even in the case of the probe that was difficult to evaluate in the first embodiment, and moreover, the targets of the same material can be used for all the probes 4. Can perform evaluation work.

The details of the ultrasonic probe inspection apparatus of the present invention are not limited to the above-described one embodiment, and various modifications are possible. As an example, the spherical ball target is used in the above-described embodiment, but the target is not necessarily a sphere, and if the target has a convex curved surface which is symmetric with respect to one axis at least in a part thereof, its symmetry axis By performing scanning in the direction orthogonal to, it is possible to inspect whether the acoustic axis of the ultrasonic wave in that direction and the central axis of the acoustic lens coincide with each other. For example, if a cylindrical target is arranged with its axial direction parallel to the X-axis and scanned in the Y-axis direction, the symmetry of the probe in the Y-axis direction can be evaluated.

Further, in the above-mentioned one embodiment, the case of inspecting the probe which focuses the beam in a spot shape has been described. However, the present invention is also applicable to the inspection of the cylindrical probe which focuses the beam in a line shape. The same applies.

[0041]

As described in detail above, according to the present invention, a high-frequency probe used in an ultrasonic microscope or the like can be used as a vibrator by utilizing a relatively large target regardless of the beam diameter. It is possible to easily and accurately inspect whether or not the sound axis of the ultrasonic beam generated by and the central axis of the acoustic lens coincide with each other. In particular, according to the invention of claim 4, even for the probe in which the V (Z) curve is not obtained, the acoustic axis of the ultrasonic beam and the acoustic lens of the ultrasonic lens are utilized by using a relatively large target regardless of the beam diameter. It is possible to easily and accurately inspect whether or not the central axis matches.

[Brief description of drawings]

FIG. 1 is a block diagram of an inspection apparatus showing a first embodiment of the present invention.

FIG. 2 is a diagram for explaining the principle of the present invention.

FIG. 3 is a diagram showing an example of a V (Z) curve.

FIG. 4 is a diagram showing an example of a normal probe.

5 is a diagram showing an example of inspection results of the probe shown in FIG.

FIG. 6 is a diagram showing an example of a defect probe.

FIG. 7 is a diagram showing an example of inspection results of the probe shown in FIG.

FIG. 8 is a diagram showing an example of inspection results of a defective probe.

FIG. 9 is a diagram for explaining a method of calculating a radius of a ball target.

FIG. 10 is a diagram showing an example of a V (Z) curve.

FIG. 11 is a diagram showing an example of a V (Z) curve.

FIG. 12 is a diagram for explaining the principle of the second embodiment of the present invention.

FIG. 13 is a diagram showing an example of the relationship between distance and reception intensity in various types of probes.

FIG. 14 is a diagram for explaining a conventional inspection method.

[Explanation of symbols]

 1 Transmitter 4 Probe 4d Acoustic Lens 6 Target 7 Receiver 8 Peak Detector 9 Microcomputer 10 XYZ Controller 11 XYZ Scanner

Claims (4)

[Claims] 1. An ultrasonic probe inspection method for evaluating the symmetry of an ultrasonic beam transmitted from an ultrasonic probe, comprising: a convex curved surface having a cross section at least one of which is axially symmetric with respect to one axis. For the target having a part, so that the direct reflected wave from this target and other reflected waves interfere with each other when being received by the ultrasonic probe, the ultrasonic probe is set to the target of the target. A step of transmitting and receiving ultrasonic waves between the ultrasonic probe and the target while relatively moving in a direction orthogonal to an axis, and a change in intensity of a reception signal obtained in the ultrasonic wave transmitting and receiving step Is output corresponding to the position of the ultrasonic probe when this received signal is obtained, and the symmetry of the ultrasonic beam can be evaluated from the symmetry of this signal strength change. Characteristic ultrasonic probe How to inspect a child. 2. An apparatus for carrying out the method for inspecting an ultrasonic probe according to claim 1, wherein the target has a convex curved surface whose cross section is axisymmetric with respect to at least one axis in at least a part thereof. Moving means for moving the ultrasonic probe relatively in a direction in which the focal position of the probe traverses the target and the axis and is orthogonal to the axis in the cross section; A transmitting unit that excites the probe to transmit an ultrasonic wave, a receiving unit that receives a signal from the ultrasonic probe, and a receiving unit that moves the ultrasonic probe by the moving unit. An ultrasonic probe inspecting apparatus, comprising: a detecting unit that detects a change in intensity of a received signal. 3. The inspection apparatus according to claim 2, wherein the transmitting means and the receiving means receive an interference wave of a target direct reflection wave reflected by the target surface and a surface acoustic wave from the target. Ultrasonic probe inspection device. 4. The inspection apparatus according to claim 2, wherein the direct reflection wave of the target reflected by at least the target surface by the transmitting means and the receiving means and the probe reflected by the tip interface of the ultrasonic probe. An ultrasonic probe inspecting device, which receives an interference wave with a reflected wave inside the probe.