JP2001318081A - Laser ultrasonic inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently detect an inspected material in a narrow part, etc., without impairing remote and non-contact properties by carrying a laser beam for transmitting/receiving an ultrasound by using an optical fiber and a small- sized inspection probe of an optical system for irradiation or the like. SOLUTION: This device has a first laser light source 1, a second laser light source 4, an optical system 5 for reception, a signal conversion means 13, and a signal processing means SP. This device is further equipped with at least one optical fiber 24 for carrying the laser beam EL oscillated by the light source 1 into close proximity with the inspected material 3, and the optical system 25 for irradiation provided on the material 3 side end of the optical fiber 24 to irradiate the material 3 with the laser beam EL under specified irradiating conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact and non-contact method for inspecting a crack or a defect or evaluating a material on a measurement object which is difficult to contact or approach, such as a small, high-temperature, narrow part or a moving part. The present invention relates to a laser ultrasonic inspection apparatus that performs destruction with high accuracy.

[0002]

2. Description of the Related Art For example, a laser ultrasonic method has recently been proposed as a means for inspecting cracks in equipment and structural materials of a power plant. For an overview of this technique, see, for example, “Yamawaki:“ Laser Ultrasonic and Non-Contact Material Evaluation ”, Journal of the Japan Welding Society, Vol. 64, No. 2, P. 104-108 (199)
5 years)), the ultrasonic wave is transmitted to the material to be inspected using thermal stress generated by irradiating a pulse laser beam in many cases, or a vaporization reaction force. On the other hand, in many cases, this is a technique of irradiating a receiving point with another laser beam that continuously oscillates, and receiving displacement or vibration velocity induced by ultrasonic waves using its straightness or coherence. It is a well-known technology that it is possible to detect cracks and intrinsic defects in materials using ultrasonic waves, or to evaluate material properties.
According to the laser ultrasonic method, these can be performed in a non-contact manner, and application to various material evaluation fields is expected.

Several different optical systems have been proposed as means for transmitting and receiving ultrasonic waves in the laser ultrasonic method.
Here, regarding the generation of ultrasonic waves by pulsed laser beam irradiation and the reception of ultrasonic waves using a Fabry-Perot resonator, which are closely related to the present invention, the block configuration of a conventional conventional laser ultrasonic inspection apparatus shown in FIG. The figure is shown.

[0004] As shown in FIG. 42, a laser beam EL oscillated from a laser light source 1 for generating an ultrasonic wave is applied through an optical system 2 to a predetermined position on the surface of a material 3 to be inspected in a predetermined beam shape. As the laser light source 1, a Q switch YAG
Lasers and the like are often used.

Therefore, in the conventional laser ultrasonic inspection apparatus, ultrasonic waves of various modes such as longitudinal waves, transverse waves, and surface waves are applied to the inspected material 3 by the interaction between the inspected material 3 and the irradiated laser beam EL. The generated ultrasonic waves cause phenomena such as reflection, scattering, and change in sound speed due to cracks, defects, or material properties of the material 3 to be inspected, and a detailed description thereof will be omitted here. I do. In any case,
When the ultrasonic wave propagated based on a certain propagation process reaches an arbitrary measurement point on the inspection target material 3, a displacement occurs at the site.

On the other hand, in FIG. 42, a laser beam ML oscillated from a laser light source 4 for ultrasonic detection irradiates a measurement point on a test object 3 via a lens 8 by a predetermined amount. As the laser light source 4, a continuous oscillation laser light source such as a frequency-stabilized He—Ne laser, an argon laser, and a YAG laser is often used.

When the measurement point is displaced by the arrival of the ultrasonic wave, the frequency of the laser beam PL irradiated and reflected at the point shifts by an amount proportional to the vibration speed due to the Doppler effect. Here, if the surface of the inspection target material 3 is optically rough, the reflected light PL is scattered, and a part of the light is incident on the optical fiber 10 through the lens 9. The transmitted light of the optical fiber 10 is guided to the Fabry-Perot resonator 17 in the receiving optical system (ROP) 5 via the coupling optical system 11.

A part of the light component PL guided to the Fabry-Perot resonator 17 is transmitted through the Fabry-Perot resonator 17 and then guided to the photodetector 13 through the lens 12. In this way, the output light of the receiving optical system 5 is converted into an electric signal by the photodetector 13, and the electric signal is amplified to a predetermined signal by the signal processing device 14 in the signal processing device SP and filtered. The result is displayed on the display device 15 and the signal is evaluated and recorded by the evaluation device 16.

Next, the operation of the Fabry-Perot resonator 17 will be described.

The Fabry-Perot resonator 17, as shown in FIG. 42, is an optical resonator composed of two opposed mirrors 17a and 17b each having a reflectance of less than 100%. Mirrors 17a and 17b when the interval r is an integer n times the wavelength λ of the incident light.
The light resonates between and the transmitted light amount I becomes maximum.

FIG. 43 shows a change in the amount of transmitted light I of the Fabry-Perot resonator 17 when the resonator length r is artificially scanned by a distance equal to or longer than the wavelength λ. As shown in FIG. 43, it can be seen that the amount of transmitted light I becomes maximum at the time when the resonator length r becomes an integer n times the wavelength λ, and then the behavior of attenuating quickly is repeated for each wavelength.

On the other hand, the cavity length r is fixed to the point A where the rate of change in the amount of transmitted light per unit length change is maximum in the curve shown in FIG. 43, and the optical frequency ν (= c / λc: speed of light) is scanned. FIG. 44 shows the change of the transmitted light amount I in the case. This is relatively fixed at the optical frequency ν (or wavelength λ) and the cavity length r
Is changed, the behavior becomes the same as that of (ν ₀ + Δν) =
The curve has a peak at r / n.

The case where the light PL reflected from the material 3 to be inspected is incident on the Fabry-Perot resonator 17 thus adjusted will be described. In a normal case, since the surface of the inspection object 3 is stationary, the frequency of the light PL reflected on the surface of the inspection object 3 remains ν ₀ , and the transmitted light amount I of the Fabry-Perot resonator 17 is It is constant at I _0.

However, when the ultrasonic wave reaches the measurement point, the frequency of the measurement light PL changes by ± ν _D due to the Doppler shift as described above, and as shown schematically in FIG. 44, the Fabry-Perot resonator The amount of transmitted light I at 17 also changes by ± _ID accordingly.

That is, the Fabry-Perot resonator 17 makes it possible to detect the arrival of the ultrasonic wave as a change in the intensity of the transmitted light. This change in light intensity is determined by an avalanche photodiode (hereinafter referred to as APD), PIN
Since it can be converted into an electric signal using a photodetector 13 such as a photodiode (hereinafter referred to as PIN-PD), a photodiode (hereinafter referred to as PD), a photomultiplier tube (hereinafter referred to as PM), an oscilloscope. If you display the time on the horizontal axis and the electric signal strength on the vertical axis using
The ultrasonic signal can be displayed and recorded on the display device 15 for observation.

On the other hand, as described above, the distance r between the mirrors 17a and 17b facing each other in the Fabry-Perot resonator 17 is sufficiently shorter than the wavelength of the incident light (for example, about 633 nm in the case of He-Ne laser light). The adjustment must be made by the spatial length, and the adjustment may be easily shifted due to thermal expansion of parts due to a change in ambient temperature or mechanical vibration around the part.

Therefore, there is conventionally a laser ultrasonic inspection apparatus provided with a resonance length control system as shown in FIG. In addition,
In FIG. 45, the same portions as those of the laser ultrasonic inspection apparatus shown in FIG. 42 are denoted by the same reference numerals, and redundant description will be omitted.

In this laser ultrasonic inspection apparatus, as shown in FIG. 45, a laser beam ML oscillated from a laser light source 4 for ultrasonic detection is
After the polarization plane is controlled by the two-wavelength plate 6a, the measurement point on the inspection target material 3 is irradiated by a predetermined amount via the polarization beam splitter 7a and the lens 8.

When the measuring point is displaced by the arrival of the ultrasonic wave, the frequency of the laser beam PL irradiated and reflected at the point shifts by an amount proportional to the vibration speed due to the Doppler effect. Here, if the surface of the inspection target material 3 is optically rough, the reflected light PL is scattered, and a part of the light is incident on the optical fiber 10 through the lens 9. The light transmitted through the optical fiber 10 is guided to the Fabry-Perot resonator 17 via the coupling optical system 11 and the polarization beam splitter 7b. A part of the light component PL guided to the Fabry-Perot resonator 17 passes through the Fabry-Perot resonator 17, and then is guided to the photodetector 13 through the lens 12 and the polarization beam splitter 7c. In this way, the output light of the receiving optical system 5 is converted into an electric signal by the photodetector 13, and the electric signal is amplified to a predetermined signal by the signal processing device 14 in the signal processing device SP and filtered. The result is displayed on the display device 15 and the evaluation device 16
The signal is evaluated and recorded.

On the other hand, a part of the laser beam ML is branched in advance by the polarization beam splitter 7a, and directly enters the Fabry-Perot resonator 17 via the polarization beam splitter 7b as the reference beam RL without passing through the material to be inspected 3. I do. The transmitted light is separated from the reflected light PL from the material 3 to be inspected by the polarization beam splitter 7 c and detected by the photodetector 18.

Since the reference light RL does not undergo any frequency shift on the optical path, the output signal level of the photodetector 18 should always be constant. If the signal level of the photodetector 18 changes,
Since this means that the resonator length r has changed for some reason, the output signal level of the photodetector 18 is input to the drive mechanism 20 such as a piezo element for driving the mirror 17b via the controller 19. By driving the mirror 17b so that the output signal level of the photodetector 18 becomes constant, the resonator length r can always be controlled to an optimum value.

With this configuration, the photodetector 13 is a high-speed detector in the MHz band for ultrasonic measurement, and the photodetector 18 is a low-speed detector in the at most kHz band for detecting disturbance vibration and temperature change. Can be used, and a signal in a specific band can be detected with high sensitivity.

On the other hand, means for controlling the Fabry-Perot resonator 17 using the measurement light PL without using the reference light RL as in the conventional laser ultrasonic inspection apparatus shown in FIG. 46 is also well known. This utilizes the fact that the band of the ultrasonic signal to be detected (MHz band) and the fluctuation band of vibration and temperature (at most kHz band) which are disturbance factors of the Fabry-Perot resonator 17 are greatly different, and the driving mechanism 20 is used. By applying a mechanism having a relatively slow response to the above, the Fabry-Perot resonator 17 is controlled so as not to respond to the ultrasonic signal but to respond only to the disturbance. When the surface of the inspection target material 3 is close to the optical mirror surface, a means for spatially guiding the reflected light PL to the Fabry-Perot resonator 17 without passing through the optical fiber 10 is also applicable.

[0024]

The laser ultrasonic inspection apparatus according to the prior art has no obstacle between the inspection object 3 and the propagation of the laser beam for transmitting and receiving ultrasonic waves in space. It is effective if it can be performed well.

However, the material 3 to be inspected has some parts such as a high temperature, a high place, a high radiation field, a complicated shape part, etc., which are difficult to contact or have poor proximity and require remote non-contact inspection means. On the other hand, they are often located at positions where it is difficult to spatially transmit the laser beam, such as in a narrow portion or inside a shield.

The surfaces of the test pieces 3 are non-uniform and have different reflection characteristics, and the signal / noise ratio (hereinafter referred to as S) of an optical signal detectable by the receiving optical system 5 such as the Fabry-Perot resonator 17. / N ratio) is also expected to be bad.

Further, when an actual inspection operation for a narrow portion is assumed, it is necessary to transport a part or all of the laser ultrasonic inspection apparatus to an inspection site using a robot or the like. Although a number of material processing and material improvement methods using a laser beam have been proposed at present, it is desirable to perform crack inspection and material evaluation before and after applying these methods.

The present invention has been made in view of the above circumstances, and an object of the present invention is to use a laser beam for transmitting and receiving an ultrasonic wave by using an optical fiber and a small inspection probe such as an irradiation optical system. It is an object of the present invention to provide a laser ultrasonic inspection apparatus capable of efficiently inspecting a material to be inspected such as a narrow portion without impairing the remote non-contact property by transmitting the information.

[0029]

According to a first aspect of the present invention, there is provided a first laser light source for oscillating a first laser beam for generating an ultrasonic wave on a material to be inspected. A second laser light source that oscillates a second laser beam applied to the material to be inspected in order to receive an ultrasonic signal generated in the material to be inspected; A receiving optical system for optically detecting information on the ultrasonic wave from a reflection component on a material surface, a signal converting unit for converting an ultrasonic signal received by the receiving optical system into an electric signal, and the signal converting unit And a signal processing means for displaying and recording the information related to the propagation of the ultrasonic wave, wherein the laser light oscillated from the first laser light source is used as the material to be inspected. Neighborhood At least one optical fiber transmitted by the optical fiber, and an irradiation optical system provided at a tip of the optical fiber on the inspection material side and irradiating the inspection object with the first laser light under predetermined irradiation conditions. It is characterized by having.

According to a second aspect of the present invention, a first laser light source for oscillating a first laser beam for generating an ultrasonic wave on a material to be inspected and an ultrasonic signal generated on the material to be inspected are received. A second laser light source that oscillates a second laser beam applied to the material to be inspected, and optically converts information about the ultrasonic wave from a reflection component of the second laser light on the surface of the material to be inspected. A receiving optical system for detecting, a signal converting means for converting an ultrasonic signal received by the receiving optical system into an electric signal, a signal processing of an output signal of the signal converting means, and a transmission of the ultrasonic wave. In a laser ultrasonic inspection apparatus having signal processing means for displaying and recording information, a laser beam oscillated from the second laser light source is transmitted to the vicinity of the material to be inspected, and the second laser light source transmits the laser light. At least one optical fiber for transmitting a reflected component of the irradiated laser light on the surface of the material to be inspected to the receiving optical system, and irradiating / collecting the laser light provided at a tip of the optical fiber on the material to be inspected side; An illumination / condensing optical system for performing light is provided.

According to a third aspect of the present invention, a first laser light source for oscillating a first laser beam for generating an ultrasonic wave on a material to be inspected and an ultrasonic signal generated on the material to be inspected are received. A second laser light source that oscillates a second laser beam applied to the material to be inspected, and optically converts information about the ultrasonic wave from a reflection component of the second laser light on the surface of the material to be inspected. A receiving optical system for detecting, a signal converting means for converting an ultrasonic signal received by the receiving optical system into an electric signal, a signal processing of an output signal of the signal converting means, and a transmission of the ultrasonic wave. A laser ultrasonic inspection apparatus having signal processing means for displaying and recording information;
At least one first optical fiber that transmits the laser light to the vicinity of the material to be inspected, and the first laser light provided at the tip of the first optical fiber on the material to be inspected side, and transmits the first laser light to the material to be inspected. An irradiation optical system for irradiating the object under predetermined irradiation conditions, and transmitting the second laser light oscillated from the second laser light source to the vicinity of the material to be inspected, and irradiated by the second laser light source. At least one second optical fiber for transmitting a reflected component of the second laser light on the surface of the inspection target material to the receiving optical system, and a second optical fiber provided at a tip of the second optical fiber on the inspection target material side. And an irradiating and condensing optical system for irradiating and condensing the second laser light.

According to a fourth aspect of the present invention, a first laser light source for oscillating a first laser beam for generating an ultrasonic wave on a material to be inspected and an ultrasonic signal generated on the material to be inspected are received. A second laser light source that oscillates a second laser beam applied to the material to be inspected, and optically converts information about the ultrasonic wave from a reflection component of the second laser light on the surface of the material to be inspected. A receiving optical system for detecting, a signal converting means for converting an ultrasonic signal received by the receiving optical system into an electric signal, a signal processing of an output signal of the signal converting means, and a transmission of the ultrasonic wave. A laser ultrasonic inspection apparatus having signal processing means for displaying and recording information; a photosynthesis / branching means for superimposing the first laser light and the second laser light on the same optical axis;
A dual-use optical system for receiving the first and second laser beams, respectively, and transmitting the first and second laser beams to the vicinity of the inspection target material; A dual-use optical fiber for transmitting a reflection component on a surface of an inspection material to the receiving optical system, and installed at the tip of the dual-purpose optical fiber on the material to be inspected, and applying the first and second laser beams to the material to be inspected. A dual-purpose irradiation / condensing optical system for irradiating under a predetermined irradiation condition and condensing the reflection component under a predetermined light collecting condition is provided.

The invention according to claim 5 is the invention according to claims 1 to 4
In the laser ultrasonic inspection apparatus according to any one of the above, the first laser light source for generating an ultrasonic wave on the material to be inspected is a pulsed Nd: YAG laser light source.

The invention according to claim 6 is the invention according to claims 1 to 4
In the laser ultrasonic inspection apparatus according to any one of the above, the second laser light source for irradiating the surface of the material to be inspected and receiving an ultrasonic signal is a second harmonic light source of a continuously oscillating Nd: YAG laser. There is a feature.

The invention according to claim 7 is the invention according to claims 1 to 4.
In the laser ultrasonic inspection apparatus according to any one of the above, an anti-reflection means for reducing the amount of return light due to the reflection of the end face is provided at the input / output section of the optical fiber.

The invention according to claim 8 is the invention according to claims 1 to 4.
In the laser ultrasonic inspection apparatus according to any one of the above, a receiving optical system for optically detecting information about ultrasonic waves is a Michelson interferometer, and the receiving optical system has a reflection component on the surface of the material to be inspected. The optical fiber for transmitting the signal is a single mode optical fiber.

According to the ninth aspect of the present invention, there are provided the first to fourth aspects.
In the laser ultrasonic inspection apparatus according to any of the above, the receiving optical system for optically detecting information about the ultrasonic wave is a Fabry-Perot optical meter, the Fabry-Perot optical meter in the surface of the material to be inspected. The optical fiber for transmitting the reflection component is one of a graded index optical fiber and a step index optical fiber.

According to a tenth aspect of the present invention, in the laser ultrasonic inspection apparatus according to the ninth aspect, the reference light for controlling the resonator of the Fabry-Perot optical meter transmits a reflection component on the surface of the material to be inspected. Characterized in that it transmits through an optical fiber having the same core diameter.

According to the eleventh aspect of the present invention, in the laser ultrasonic inspection apparatus according to any one of the first to fourth aspects,
A focus dispersive optical system for inputting the first laser light oscillated from the first laser light source to the optical fiber is provided.

Therefore, according to the first to eleventh aspects of the present invention, a laser beam for transmitting and receiving an ultrasonic wave is transmitted using an optical fiber, an irradiation optical system, or a small inspection probe of an irradiation / condensing optical system. By transmitting, it is possible to efficiently inspect the inspection target material in the narrow portion without impairing the remote non-contact property.

[0041]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a laser ultrasonic inspection apparatus according to the present invention will be described below with reference to the drawings. In addition,
In each embodiment and each modified example, the same or corresponding portions as those in the conventional configuration are denoted by the same reference numerals as those in FIGS. 42 to 46, and overlapping description will be omitted, and only different configurations will be described.

[First Embodiment] FIG. 1 is a block diagram showing a first embodiment of a laser ultrasonic inspection apparatus according to the present invention.

In this embodiment, as shown in FIG. 1, an ultrasonic wave excited by a first laser light EL oscillated from a laser light source 1 for generating an ultrasonic wave as a first laser light source is used as a reference light RL. The reflected light PL, which is the reflected light from the measurement point on the material 3 to be inspected, is applied to the Fabry-Perot resonator 17 that is stably controlled using the １ ／ wavelength plate 21, the polarizing beam splitter 7 d, the mirror 22, 1 / The configuration is the same as that of FIG. 45 except that the optical fiber 10 is not used, except for the operation of measuring by making the light enter the Fabry-Perot resonator 17 via the two-wavelength plate 6b.

That is, in this embodiment, as in the case of the laser ultrasonic inspection apparatus shown in FIG. 45, the first (laser) light EL for oscillating the laser light (first laser light) EL for generating ultrasonic waves on the material 3 to be inspected. A laser light source 1 as a laser light source of the above, and a second laser light oscillating a laser light (second laser light) ML applied to the inspection target material 3 to receive the generated ultrasonic signal.
A laser light source 4 as a laser light source, and a receiving optical system 5 for optically detecting information on ultrasonic waves from a reflection component of the second laser light ML on the surface of the inspection target material 3.
And a photodetector 1 as signal conversion means for converting an ultrasonic signal received by the receiving optical system 5 into an electric signal.
3 and a signal processing device SP for appropriately processing the output signal of the photodetector 13 to display and record information on the propagation of the ultrasonic wave.

In this embodiment, the laser light EL oscillated from the laser light source 1 is incident on a fiber incidence optical system 23 as a first incidence optical system, and the fiber incidence optical system 23 is connected to an optical fiber ( At the rear end of the first optical fiber 24, a fiber emission optical system 25 as an irradiation optical system is mounted at the front end of the optical fiber 24.

Therefore, the laser light EL oscillated from the laser light source 1 is incident on the optical fiber 24 via the fiber incident optical system 23, and is transmitted to the vicinity of the material 3 to be inspected by using the optical fiber 24. The surface of the inspection target material 3 is irradiated in a predetermined irradiation shape by a fiber emission optical system 25 provided at the tip of the fiber 24.

Next, the operation of the present embodiment will be described.

Normally, as the laser beam EL used for ultrasonic excitation, a pulse laser beam having a pulse energy of mJ class or more is used, but this is at a harmful level when erroneously irradiated on the human body or the like. Therefore, in order to spatially propagate the light over a long distance, safety considerations such as providing an optical path shielding means are required.

Therefore, as shown in FIG.
L through an optical system 23 for fiber incidence to an optical fiber 24
Is transmitted to the vicinity of the inspection target material 3 using the optical fiber 24, and is irradiated from the laser light source 1 to the fiber by irradiating the surface of the inspection target material 3 with a predetermined irradiation shape by the fiber emission optical system 25. It is sufficient to shield the optical path only for a very short distance from the optical system for incidence 23 and the optical system for emission from the fiber 25 to the material 3 to be inspected, and it is possible to reduce the cost for installing the optical path shielding means.
The inspection target material 3 installed in a narrow part or the like can be efficiently inspected without impairing the remote non-contact property.

[Modification of First Embodiment] FIG. 2 is a block diagram showing a modification of the first embodiment of the laser ultrasonic inspection apparatus according to the present invention, and FIG. 3 is a diagram showing the effect of the structure of FIG. FIG.

In this modified example, as shown in FIG.
26n is split into a predetermined number of beams by a plurality of optical splitters 26a, 26b,... 26n, and each of the beams is split through a plurality of optical fibers 24a, 23b,. .. 24n, and a plurality of optical systems 25a, 25b,.
At 5n, a plurality of points on the surface of the material 3 to be inspected are irradiated.

Regarding the excitation of ultrasonic waves by laser beam irradiation, the directivity of ultrasonic waves generated depending on the irradiation shape,
It is known that the frequency and the like can be controlled [for example, C.I. B. Scrubby and L.S. E. FIG. Dr
ain, "Laser Ultrasonics: T
echniques and Application
s "(Bristol: Adam Hiller) 19
90 years etc.].

In the normal case, such a spot shape is formed by using a lens system. For example, using the configuration shown in FIG. 2, the irradiation spot is formed as shown by points 27a, 27b,. When arranged in a line, sound waves on a circle centered on each point are phase-matched on the surface of the material 3 to be inspected.
A surface wave which is strengthened in the directions of D1 and D2 and hardly propagates in the vertical direction can be formed.

As described above, according to this modification, the same effects as those of the first embodiment can be obtained.

[Second Embodiment] FIG. 4 is a block diagram showing a second embodiment of the laser ultrasonic inspection apparatus according to the present invention.

In the present embodiment, as shown in FIG. 4, the ultrasonic wave excited by the laser beam EL is measured by the Fabry-Perot resonator 17 in which the reference beam RL is used to stably control the ultrasonic wave. The measurement light PL reflected from the point is 1
/ 4 wavelength plate 21, polarizing beam splitter 7d, mirror 2
The measurement is performed by entering the Fabry-Perot resonator 17 through the half-wave plate 6b.

In this embodiment, a fiber incident optical system 28 as a second incident optical system for inputting measurement light ML as a second laser beam to an optical fiber 29 as a second optical fiber is provided. An optical fiber 29 that transmits the measurement light ML to the vicinity of the inspection target material 3 and transmits a reflection component of the measurement light ML on the surface of the inspection target material 3 to the receiving optical system 5; A fiber emitting optics as an irradiating / light collecting optical system for irradiating the measuring light ML to the material to be inspected 3 at a predetermined irradiation condition on the side tip under predetermined irradiation conditions, and condensing its reflection component under predetermined light collection conditions. And a system 30.

That is, the fiber input optical system 28 is attached to the rear end of the optical fiber 29, and the fiber output optical system 30 is attached to the distal end.

The structure and operation other than the above are shown in FIG.
5 is the same as the conventional example shown in FIG.

Therefore, in the present embodiment, the material to be inspected 3
Not only the reflected light PL from
8. The transmission of the measurement light ML using the optical fiber 29 and the fiber emission optical system 30 also uses the optical fiber.
At this time, the reflected light PL from the material 3 to be inspected propagates along the same path and is guided to the Fabry-Perot resonator 17.

With such a configuration, it is possible to receive the ultrasonic wave only by installing the small fiber emitting optical system 30 near the relatively high energy laser beam EL. The ultrasonic inspection can be performed at the same time by using together with an existing pulse laser system such as a cutting device, a laser processing device, and a laser material improving device.

[First Modification of Second Embodiment] FIG. 5 is a block diagram showing a first modification of the second embodiment of the laser ultrasonic inspection apparatus according to the present invention, and FIG. 6 is based on the constitution of FIG. It is explanatory drawing which shows an effect.

In the first modification, as shown in FIG. 5, a transmission system comprising a fiber input optical system 28, an optical fiber 29 and a fiber output optical system 30 for transmitting the measurement beam ML and the reflected light PL. The system has two systems. That is, the transmission system of the first modified example is composed of optical systems 28a and 28b for fiber incidence, optical fibers 29a and 29b,
As in the case of the fiber emission optical systems 30a and 30b, two systems are configured.

At this time, the fiber input optical systems 28a, 28a
At the front stage of FIG.
While an imaging optical system 31 for transferring the image to the Perot resonator 17 is provided, an imaging optical system 32 for transferring the transferred image to the light detection surface is provided in front of the photodetectors 13a and 13b. Have been. This makes it possible to individually detect the beams that have propagated through the respective transmission systems, and it is possible to perform measurement at a plurality of points using one Fabry-Perot resonator 17.

Although the configuration using two transmission systems has been described in FIG. 5, a configuration using a larger number of transmission systems is also possible based on this modification. In the invention disclosed in Japanese Patent Application Laid-Open No. Hei 10-351440, as shown in FIG. 6, the ultrasonic wave US transmitted by the laser beam EL is detected by a plurality of (two in the figure) measurement beams PL1 and PL2. Means for improving the detection performance of the crack 33 by measuring both the ultrasonic component UT transmitted through the crack 33 and the reflected component UR has been proposed. In order to realize this method, a configuration in which a measurement beam is spatially propagated and guided to a measurement point can be considered. However, if an optical fiber as shown in FIG. 33 can further improve the detection performance.

[Second Modification of Second Embodiment] FIG. 7 is a block diagram showing a second modification of the second embodiment of the laser ultrasonic inspection apparatus according to the present invention.

The configuration and the basic operation of the second modification are the same as those of the second embodiment shown in FIG. 5, but in this second modification, as shown in FIG.
Is used to enable distribution measurement rather than multi-point reception.

The laser beam applied to the inspection target material 3 by the fiber emission optical system 35 is reflected at each point on the surface of the inspection target material 3, but the positional relationship is preserved by the fiber bundle 34. The spatial information, that is, the image of the end face of the fiber bundle 34 is transferred to the Fabry-Perot resonator 17 by the imaging optical system 31. The light emitted from the Fabry-Perot resonator 17 is transmitted to the imaging optical system 32.
When the image is transferred to the detection surface of the two-dimensional array type photodetector 36 through the above, information of each point of the surface of the inspection target material 3 is detected by each element of the two-dimensional array type photodetector 36, Can be spatially visualized.

In this case, as the two-dimensional array type photodetector 36, besides a normal CCD sensor, a CCD sensor with an image intensifier can be used.

In the second embodiment and each of the modifications, the optical fiber 29 or the fiber bundle 3 is used as a transmission system.
4, the same operation and effect can be obtained by spatial transmission using an optical system such as an imaging lens.

[Third Embodiment] FIG. 8 is a block diagram showing a third embodiment of the laser ultrasonic inspection apparatus according to the present invention.

In the present embodiment, the transmission system for transmitting the laser beam EL of the first embodiment and the transmission system for transmitting the measurement light ML and the reflected light PL of the second embodiment are used in combination.

That is, in the present embodiment, as shown in FIG. 8, a fiber incident optical system 23 for injecting a laser beam EL into one or a plurality of optical fibers 24, and a laser beam EL corresponding thereto are received. One or a plurality of optical fibers 24 to be transmitted to the vicinity of the inspection material 3, and a laser beam EL is irradiated to the inspection material 3 at a predetermined irradiation condition on the tip of the one or more optical fibers 24 on the inspection material 3 side. And a fiber input optical system 2 for inputting the laser beam ML to one or a plurality of optical fibers 29.
8, one or a plurality of optical fibers 29 for transmitting the laser light ML to the vicinity of the material 3 to be inspected and transmitting the reflected component of the laser light ML on the surface of the material 3 to the fiber emitting optical system 30; An irradiation / light condensing optical system that irradiates a laser light ML to the tip of the optical fiber 29 on the material to be inspected 3 under predetermined irradiation conditions and condenses the reflected component thereof under predetermined light condensing conditions. And a fiber emission optical system 30.

With this configuration, it is possible to perform an inspection by installing only the optical systems 25 and 30 for emitting fibers in the vicinity of the inspection target material 3. In the case where the inspection target material 3 is located in a narrow portion, etc. Also, the laser ultrasonic inspection can be performed without transmitting the laser light spatially.

[Fourth Embodiment] FIG. 9 is a block diagram showing a fourth embodiment of the laser ultrasonic inspection apparatus according to the present invention.

In the present embodiment, the transmission system for transmitting the laser beam EL of the first embodiment and the transmission system for transmitting the measurement light ML and the reflected light PL of the second embodiment are used in combination. The transmission system is the same.

That is, in the present embodiment, as shown in FIG. 9, the optical path of the laser light EL is adjusted by an optical system 37 such as a mirror, and this laser light EL is measured by a light splitter 38 as a light combining / branching means. After superimposing coaxially with
A fiber incident optical system 39 as a dual-purpose incident optical system,
An optical fiber 40 as a dual-use optical fiber and a fiber emission optical system 41 as a dual-use irradiation / condensing optical system transmit light to the material 3 to be inspected.

In such a configuration, the reflected light PL from the material 3 to be inspected is guided to the Fabry-Perot resonator FP through the same path. At this time, the reflected component of the laser beam EL also includes the Fabry-Perot resonator. Resonator 17 and photodetector 1
3 is incident as stray light and becomes noise. In this case,
Laser light sources having different wavelengths are used for the laser light source 1 and the laser light source 4, and the laser light source 4 is provided in front of the photodetector 13.
It is necessary to prevent the reflected component of the laser beam EL from being incident on the photodetector 13 by installing a narrow band optical filter 42 that transmits only the oscillation wavelength of the laser beam EL.

In the laser ultrasonic inspection apparatuses of the first to fourth embodiments, the laser light source 1 is provided with a fundamental wave Nd which can oscillate laser light having a pulse energy sufficient to excite ultrasonic waves. A YAG laser light source is used.

In the laser ultrasonic inspection apparatuses of the first to fourth embodiments, the laser light source 4 can oscillate laser light having coherence and narrow band enough to receive ultrasonic waves. And a second harmonic Nd: YAG laser light source having a different wavelength from the fundamental wave of the Nd: YAG laser.

[Fifth Embodiment] FIGS. 10A and 10B are explanatory views showing a fifth embodiment of the laser ultrasonic inspection apparatus according to the present invention.

This embodiment is different from the laser ultrasonic inspection apparatus of the first to fourth embodiments in that the optical fibers 24, 2
At least one of the input / output portions of the optical fibers 9, 40 and the fiber input optical systems 23, 28, 39 or the optical fibers 24, 29, 40 and the fiber output optical systems 25, 30, 41 as the irradiation / condensing optical system. And anti-reflection means for reducing the amount of return light due to the reflection of the end face.

That is, in this embodiment, the optical fiber 2
4, 29 and 40 are characterized by having an anti-reflection function as shown in FIG. 10B, for example. An ordinary optical fiber has a structure composed of a core Cr and a clad Cl as shown in FIG. 10A, and when the measurement light ML is incident thereon, the incident light is reflected by the incident light PL from the material 3 to be inspected. And the end face reflection Lx of the emission section are mixed,
The light propagates along the same optical axis and is detected by the photodetector 13 and the reflected light R
In addition to the noise in the L measurement, the light returns to the laser light source 1 or 4 through the incident optical path and adversely affects the stability of the light source.

Thus, as shown in FIG. 10B, if both ends of the fiber are inclined at an appropriate angle, the stray light of the end face reflection Lt or the end face reflection Lx will have the same optical axis as the reflected light PL or the measurement light ML. , And good measurement can be realized. Therefore, according to the present embodiment,
It is possible to suppress the influence of the reflection from the fiber incident surface.

[Modification of Fifth Embodiment] FIG. 11 is an explanatory view showing a modification of the fifth embodiment of the laser ultrasonic inspection apparatus according to the present invention.

This modified example is a modification of the laser ultrasonic inspection apparatus of the first to fourth embodiments, as shown in FIG.
Are respectively formed in the containers 44a and 44b, and the insides of the containers 44a and 44b are respectively filled with fiber cores Cr.
, The end face reflection Lt of the incident part and the end face reflection Lx of the emission part can be considerably reduced.

The use of a fiber having an anti-reflection coating on the input / output end face of the fiber is also included in the scope of the present embodiment. Further, even when the optical fibers 23 and 29 are connected on the way using a connector or the like, the same effect can be obtained by performing the same processing as described above on the end face.

[Sixth Embodiment] FIG. 12 is a block diagram showing a sixth embodiment of the laser ultrasonic inspection apparatus according to the present invention.

In this embodiment, as shown in FIG. 12, a Michelson interferometer for measuring a surface displacement induced by an ultrasonic wave as the receiving optical system 5 in the laser ultrasonic inspection apparatus of the first to fourth embodiments. Is used. here,
In the Michelson interferometer, since the coherence of the interference light becomes a problem, it is efficient to use a single mode optical fiber as the optical fiber 29.

In the receiving optical system 5 shown in FIG. 12, quarter-wave plates 21a and 21b are provided, and deflection beam splitters 7e and 7f are provided.

On the other hand, the laser ultrasonic inspection apparatus shown in FIGS. 1, 2, 4, 5, 7, 8, and 9 uses a Fabry-Perot resonator 17 as the receiving optical system 5.
Here, the type of optical fiber used in each embodiment is not limited. However, when the Fabry-Perot resonator 17 is used, the optical fiber 29 is a multi-mode optical fiber such as a step index optical fiber or a graded index optical fiber. It is more efficient to use.

[Seventh Embodiment] FIG. 13 is a block diagram showing a receiving optical system of a laser ultrasonic inspection apparatus according to a seventh embodiment of the present invention. FIG. 13 shows only the portion of the Fabry-Perot resonator 17, which is the receiving optical system 5, in an extracted manner.

In this embodiment, as shown in FIG. 13, a fiber incident optical system 28b, an optical fiber 29b, and a fiber emitting optical system 30b are installed in the optical path of the reference light RL in the same manner as the optical path of the measurement light ML. ing. That is, the reference light RL for controlling the Fabry-Perot resonator 17 is transmitted through the third optical fiber 29 b having the same core diameter as the second optical fiber 29.

As a result, Fabry-Perot resonator 17
The optical characteristics such as the beam diameter and the mode of the reference light for controlling the reference light become much closer to the actually measured reflected light RL, and it is possible to provide the receiving optical system 5 that is highly sensitive and easy to adjust.

[Eighth Embodiment] FIG. 14 is a block diagram showing a fiber incidence optical system of an eighth embodiment of the laser ultrasonic inspection apparatus according to the present invention.

The present embodiment has a focal point dispersion type optical system for making the laser light oscillated from the laser light source 1 enter the optical fiber 24 as shown in FIG. That is,
This focus dispersion type optical system includes a concave lens 46 for enlarging a laser beam EL, and a microlens array for adjusting an optical path so that a beam passing through each point in a beam cross section of the laser beam EL is condensed at a spatially different position. 47 and a lens 48.

In the above-described configuration, the laser beam EL oscillated from the laser light source 1 is temporarily expanded by the concave lens 46, and thereafter, the beam passing through each point in the beam cross-section is spatially different by the microlens array 47. The optical path is adjusted so as to be condensed, and then the optical fiber 2 is
4.

Here, since the laser beam EL has a relatively high pulse energy, if it is simply condensed spatially at one point, a breakdown occurs at that point and the optical fiber 24
Etc. may be damaged.

Therefore, according to the structure shown in FIG. 14, since the laser beam EL does not have a single point of focus, there is no concentration of energy, the optical fiber 24 is not damaged, and the laser beam EL having a higher energy is used. The optical fiber 2
4 can be transmitted.

As described above, according to the first to eighth embodiments, a small inspection probe of an optical fiber, an irradiating optical system or an irradiating and condensing optical system is used for transmitting and receiving a laser beam for transmitting and receiving ultrasonic waves. , The material to be inspected 3 in a narrow portion can be efficiently inspected without impairing the remote non-contact property.

[Ninth Embodiment] FIG. 15 is a block diagram showing a ninth embodiment of the laser ultrasonic inspection apparatus according to the present invention.

In the ultrasonic excitation method by laser irradiation, a longitudinal wave, a transverse wave, a surface wave, and the like are simultaneously generated as described above. Among these ultrasonic modes, for example, longitudinal waves and transverse waves propagating inside the material 3 to be inspected are suitable for measuring defects, material properties, or plate thickness inside the material 3 to be inspected. Propagating surface waves are suitable for measuring surface cracks and surface properties or the properties of a film attached to the surface.

Here, these ultrasonic modes have a unique sound speed determined by the material of the material 3 to be inspected. For example, when the material to be inspected 3 is steel, the surface acoustic wave velocity is about 2,900 m / sec.
c, the longitudinal wave velocity is about 6,000 m / sec, and the transverse wave velocity is about 3,240 m / sec.

[0104] Thus, this embodiment, (the distance from the sound source: _d b ~d _e) spatial region to be observed in advance, as shown in FIG. 15 and the known acoustic velocity v

(Equation 1) A time gate 49 having a time interval of
, It is possible to observe a desired signal without being interfered by another mode.

As described above, in the present embodiment, the signal processing means 14 extracts a surface wave component propagating on the surface of the material 3 to be inspected, a longitudinal wave component or a transverse wave component propagating therein, from the generated ultrasonic waves. From the information, the presence / absence of cracks on the surface, inside and back of the material 3 to be inspected, the size and surface wave of the crack, the thickness of the material to be inspected, the state of the back surface, and the propagation of longitudinal or transverse waves are displayed and recorded. It was done.

[Tenth Embodiment] FIG. 16 is a block diagram showing a tenth embodiment of the laser ultrasonic inspection apparatus according to the present invention, and FIG. 17 is a diagram showing signal processing using wavelet transform in the tenth embodiment. FIG.

The ultrasonic signal detected by the receiving optical system 5 and the photodetector 13 may be, for example, a disturbance noise or a noise generated by the photodetector 13 or the signal processing device 14 due to noise or the like. In some cases, the N ratio cannot be obtained well.

At this time, by installing the S / N ratio improving means 50 in the signal processing device 14 as in this embodiment,
Good signal observation becomes possible. As the S / N ratio improving means 50, for example, when it is known that a signal is mixed in a certain frequency band, a low-pass filter, a high-pass filter, or a band-eliminating filter for removing the band may be used. If the frequency band of the component is known in advance, or if it is desired to focus only on the signal component of a certain frequency band, a band-pass filter that passes only that band may be used.

If the dominant noise has a random frequency component such as thermal noise, it may have an averaging function of averaging the signals a plurality of times. In this case, if the transmission and reception intervals of the ultrasonic waves by the laser are always the same, averaging processing using the transmission timing of the laser light source 1 as a reference time (trigger) is convenient for timing control. If the transmission / reception interval changes with time due to problems such as scanning of transmission / reception points,
The ultrasonic signal may be digitized and stored, and only data that can be regarded as having substantially the same distance may be selected from the data and averaged.

Further, when the ultrasonic signal to be observed is a repetitive signal having a waveform that can be considered to be substantially similar, such as an ultrasonic echo signal, an autocorrelation of the signal or a signal serving as a reference prepared in advance. The S / N ratio can also be improved by calculating the cross-correlation with.

When the frequency component included in the detected ultrasonic signal is important, a specific phenomenon can be detected with high sensitivity by performing signal processing using a wavelet transform as shown in FIG. It is possible. Note that these processes include not only a case where the output signal of the photodetector 13 is processed as an analog electric signal, but also a case where an analog-digital converter is installed in the signal processing unit 14 and processed as a digital signal. .

As described above, in the present embodiment, in the signal processing device 14, the received ultrasonic signal is subjected to signal filtering in an appropriate band, signal averaging a plurality of times, correlation processing in an appropriate region, or appropriate processing. Wavelet transform processing of a band is performed.

[Eleventh Embodiment] FIG. 18 is a block diagram showing an eleventh embodiment of the laser ultrasonic inspection apparatus according to the present invention.

In the present embodiment, as shown in FIG. 18, laser light EL and measurement light
In step 9, the light is transmitted to the optical systems 25 and 30 for emitting fibers, and the optical systems 25 and 30 for emitting fibers are mounted on individual drive mechanisms 51 a and 51 b.
The inspection of one point or a plurality of points on the inspection target material 3 is automatically performed by configuring the a and 51b so that they can be scanned and driven on the rail 52 laid in advance. The driving mechanism 51a, 51b and the rail 52 constitute a scanning unit.

Therefore, in the present embodiment, there is provided scanning means for scanning the emission optical systems 25 and 30 individually or simultaneously, and the signal processing device 14 receives the ultrasonic information received by the scanning means. Multi-dimensional display is performed in association with the scanning position.

In the case where the material to be inspected 3 is in a narrow part or a high place, or when the material to be inspected 3 itself is difficult to access due to high temperature, high radioactivity, etc. Even when the same location is regularly inspected, there is an effect that an inspection at a predetermined position can be performed in a short time by the rail 52 installed in advance.

Further, if a position detecting mechanism is attached to the driving mechanisms 51a and 51b, it is possible to quantitatively associate the inspection record with the inspection position.

In the present embodiment, the optical systems 25 and 30 for emitting fibers are connected to the individual driving mechanisms 51a and 51a.
Although the example in which the antennas are mounted on 1b is shown, if they are installed on one drive mechanism, it becomes possible to keep the transmission and reception intervals of ultrasonic waves constant at all times.

[Twelfth Embodiment] FIGS. 19A and 19B
FIG. 19 is an explanatory diagram showing a display example of a twelfth embodiment of the laser ultrasonic inspection apparatus according to the present invention.

FIGS. 19A and 19B are display examples of data measured by a laser ultrasonic inspection apparatus capable of scanning a transmission / reception position as shown in FIG. 18, for example.

Now, it is assumed that the material 3 to be inspected having the thinned portion G on the back surface as schematically shown in FIG. Then, since the thinned portion G is thinner than the other portions, the propagation time of the ultrasonic wave US that propagates inside, such as a longitudinal wave or a transverse wave, differs. Therefore, near the previously expected travel times to the ultrasonic signals obtained during scanning (described above t _b ~t _e) by installing a time gate, 19 measurement data at each position (y) in accordance with the scan (A ), The back surface shape of the inspection target material 3 can be measured as shown by the thick dotted line in the figure.

Furthermore, if the speed of sound in the material to be inspected 3 is known, its shape can be quantitatively detected.

FIGS. 20A and 20B are display examples when scanning is performed two-dimensionally, which is one-dimensionally shown in FIG.
In the ultrasonic signal obtained as shown in (A), the time at which the peak is reached is associated with the position scanned two-dimensionally. It is displayed in a color (shade) so that it becomes lighter. FIGS. 21A and 21B are display examples when the same measurement result is three-dimensionally shown, and it can be seen that the back surface shape of the inspection target material 3 can be visualized by the present apparatus.

On the other hand, FIGS. 22A and 22B show an example in which attention is paid to surface waves. When cracks F1, F2, and F3 exist on the material 3 to be inspected as shown in FIG. 22B, a surface wave having directivity in the direction (y) along a path indicated by a two-dot chain line in the figure is generated. Upon transmission and reception, if there is a crack F, a surface wave is reflected at the crack F, and a crack echo is observed.

Therefore, if a time gate corresponding to the inspection area is provided and the ultrasonic signal level in the time area is displayed in shades or colors, the surface crack can be visualized as shown in FIG. .

As described above, in the present embodiment, the display device 15 of the signal processing device SP transmits the intensity information of the received ultrasonic signal, the measured crack size information, or the measured ultrasonic propagation information to the transmission / reception position. It is displayed in a multidimensional manner in association with lines, shades or colors.

As described above, according to the ninth to twelfth embodiments, appropriate electric signal processing is applied to the received ultrasonic signal, or the surrounding atmosphere or surface condition of the inspection material is adjusted. Thereby, it is possible to improve the S / N ratio to improve the evaluation accuracy and to present the detected information so that the inspector can easily understand it.

[Thirteenth Embodiment] FIG. 23 is a block diagram showing a thirteenth embodiment of the laser ultrasonic inspection apparatus according to the present invention.

In this embodiment, as shown in FIG. 23, the laser light source 1, the receiving optical system 5, the photodetector 13 and the signal processing device 14 are mounted on a trackless traveling vehicle 53 as a transport means.
A fiber emission optical system 25 for the laser beam EL and a fiber emission optical system 30 for the measurement light ML are respectively installed on the inspection arm 54 mounted on the trackless carriage 53. Further, the trackless carriage 53 has a position detecting device 55 for confirming the inspection position.
4 is provided with a monitoring TV camera 56 as monitoring means for monitoring the inspection work.

The communication device 5 is provided on the laser light source 1, the receiving optical system 5, the photodetector 13, and the signal processing device 14.
7a is installed, while remote driving as control means
The communication device 57b is installed on the control device 58.

Therefore, the ultrasonic data measured by the laser light source 1, the receiving optical system 5, and the photodetector 13 are processed by the signal processing device 14, and then transmitted to the communication devices 57a and 57b together with the position data and the image data. Then, it is wirelessly transmitted to a remote drive / control device 58. The measurement data, the position data, and the image data received by the drive / control device 58 are displayed on the display device 15 in association with each other, and are recorded on the evaluation device 16.

It is to be noted that a design drawing or CAD data of the material 3 to be inspected and its peripheral devices are recorded in advance in the evaluation device 16 and the design information of the corresponding devices and parts, based on the inspection position data and the image data. Display device 1 such as shape
By displaying the information at the same time, more efficient and advanced inspection can be performed.

The drive / control device 58 can drive and control the trackless carriage 53 and the inspection arm 54 from a remote place. According to such a configuration, the inspection by the laser ultrasonic inspection apparatus can be performed even when the inspected material 3 is an operating device, or when the inspector is difficult to access such as a high temperature or a high radiation environment.

As the monitoring means, in addition to the monitoring TV camera 56 and the distance sensor, a ferrite detector for detecting weld metal, a three-dimensional TV camera to which double parallax is applied, and the like can be used.

[First Modification of Thirteenth Embodiment] FIG. 24 is a configuration diagram showing a first modification of the thirteenth embodiment of the laser ultrasonic inspection apparatus according to the present invention.

The embodiment shown in FIG. 23 is an example in which a laser type ultrasonic inspection device is mounted on a wireless, trackless traveling vehicle. The first modified example shown in FIG. 24 is a case with a track.

In the first modified example, as shown in FIG. 24, a track 59 is fixed and set in advance.
Monorail type traveling vehicle 6 as a transport means traveling on the top
The optical system 39 for emitting a fiber is mounted on the reference numeral 0. In this case, if the monorail traveling vehicle 60 has a sufficient space, the laser light source 1, the receiving optical system 5, the photodetector 1
3 and the signal processing device 14 can be mounted on the monorail traveling vehicle 60, but in many cases there is no space, and since the optical fiber 40 can be routed using the track 59, they are driven. -It is simple to install in a remote base station together with the control device 58 and to mount only the head unit.

Further, as in the thirteenth embodiment, if a monitoring camera, a distance sensor, a position sensor, and the like are mounted on the monorail traveling vehicle 60, a more reliable inspection can be performed.

[Second Modification of Thirteenth Embodiment] FIG. 25 is a block diagram showing a second modification of the thirteenth embodiment of the laser ultrasonic inspection apparatus according to the present invention.

The second modification is a modification of the first modification.
As shown in FIG. 25, a portable rail 61 is used as a track, and a traveling vehicle 62 is provided as a transport means traveling on the portable rail 61. This traveling cart 62
By providing a fine movement mechanism capable of fine movement in a direction parallel to the optical axis, the focus of the laser light EL and the measurement light ML can be finely adjusted.

With such a configuration, the material to be inspected 3
The inspection can be efficiently performed even in a case where the inspection is difficult, such as a case where a plurality of pipes are installed at a high place.

In the thirteenth embodiment and each of the modifications thereof, the position detecting means of the transfer means provided on the transfer means such as the trackless carriage 53 and the laser light EL which is the first and second laser light and An irradiation position identification unit for detecting the irradiation position of the measurement light ML and an inspection position identification unit for detecting the inspection target material 3 and the inspection position on the inspection target material 3 from the information may be provided.

In the thirteenth embodiment and its modifications, the signal processing device 14 is provided with a multidimensional information database relating to the dimensions and the shape of the material 3 to be inspected. The output information of the identification means and the information of the corresponding part of the multidimensional information database may be displayed in association with each other.

[Fourteenth Embodiment] FIG. 26 is a block diagram showing a fourteenth embodiment of the laser ultrasonic inspection apparatus according to the present invention.

The fourteenth embodiment relates to a case where the material 3 to be inspected is a nuclear reactor 63 or a nuclear reactor internal structure 64, and the surrounding atmosphere may be air or water. Transmission of laser light EL capable of transmitting ultrasonic waves is described in "Yuji San
o et. al. “Process and app
ligation of shock compresses
session by nano-second pulse
s of frequency-doubled N
d: YAG laser, “Proc. ofALP
HA'99 SPIE, Osaka, November
er 1999, a pulsed light transmission device 65 into a furnace is known.

In this embodiment, the laser light source 1, the receiving device 5, and the photodetector 1 are placed in an optical equipment room 66 provided on the reactor 63.
3. By installing the signal processing device 14 and the like, and installing the optical fiber 29 therefrom along the pulse light transmission device 65 which is an example of a remote control mechanism for a furnace as a conveying means,
The measurement light ML is guided to the inspection position, and the pulse light transmission device 65
The measurement light ML is transmitted and received by the fiber emission optical system 30 installed at the tip of the reactor 63, so that the
Alternatively, it is an apparatus for inspecting the furnace internal structure 64.

[First Modification of Fourteenth Embodiment] FIG. 27 is a block diagram showing a first modification of the fourteenth embodiment of the laser ultrasonic inspection apparatus according to the present invention.

In this modification, as shown in FIG.
In the case where the laser light EL is also transmitted by an optical fiber without using the pulse light transmission device 67 as in the fourth embodiment, the inside of the reactor as a transporting means that moves along the reactor 63 or the internal structure 64 is used. The optical systems 25 and 30 for emitting the fiber are provided to the furnace inspection robot 67 which is an example of the remote control mechanism for the fiber.
Is installed, and the laser light EL and the measurement light ML are transmitted to the fiber emission optical systems 25 and 30 by the optical fibers 24 and 29.

By applying this laser ultrasonic inspection apparatus, it is possible to efficiently inspect narrow portions under severe conditions such as in the nuclear reactor 63. In this case, in consideration of the radiation resistance of the material, it is desirable to use quartz for the material of the optical components such as the lens and the optical fiber and to use stainless steel or aluminum for the structural material.

[Second Modification of Fourteenth Embodiment] FIG. 28 is a configuration diagram showing a second modification of the fourteenth embodiment of the laser ultrasonic inspection apparatus according to the present invention.

In this modification, as shown in FIG. 28, the material to be inspected is a pipe 68, and the inside of the pipe 68 is moved, scanned,
A fiber output optical system 41 is provided to a mobile robot 69 which is an example of a pipe inner surface traveling mechanism as a transport means that can be fixed and stopped.
Is installed, and the transmission of the laser light EL and the transmission and reception of the measurement light ML are performed using the optical fiber 40, so that the inner surface of the longitudinal pipe can be efficiently inspected.

[Fifteenth Embodiment] FIGS. 29A and 29B
FIG. 15 is a configuration diagram showing a fifteenth embodiment of the laser ultrasonic inspection apparatus according to the present invention.

In this embodiment, as shown in FIGS. 29A and 29B, the material to be inspected is a pipe 68, and a track 70 is laid on the outer surface of the pipe 68. The laser light source 1 and the optical systems 30a and 30b for emitting fibers are mounted on the traveling carriage 71. The track 70 has an axial movement mechanism (not shown). Then, the track 70 and the traveling vehicle 7
Reference numeral 1 denotes a pipe outer surface traveling mechanism as a transport means.

In the above configuration, the laser light EL oscillated from the laser light source 1 is applied to the lens 2 and the irradiation mirror 72
The measurement light ML oscillated from the laser light source 4 (not shown) while being transmitted through the waveguide 73 provided with a and 72b and irradiating the surface of the pipe 68 has two lines based on the configuration shown in FIG. The light is transmitted by the optical fibers 29a and 29b, and is irradiated on the surface of the pipe 68 by the optical systems 30a and 30b for emitting the fibers.

Here, the fiber emission optical systems 30a, 30
If 0b is installed so as to face the pipe 68, for example, the reflected light PL of the measurement light ML irradiated by the fiber emission optical system 30a is collected by the same fiber emission optical system 30a and detected by the reception optical system 5. Will do. On the other hand, FIG.
As shown in (A), if the two fiber exit optical systems 30a and 30b are arranged at an appropriate angle, the regular reflection component of the measurement light ML obliquely applied to the pipe 64 from the fiber exit optical system 30a. To the fiber exit optical system 30
Irradiation and focusing can be performed by different fiber emission optical systems, for example, b is focused and vice versa.
With this configuration, the inspection of the longitudinal pipe can be performed automatically and efficiently.

[Sixteenth Embodiment] FIG. 30 is a perspective view showing a sixteenth embodiment of the laser ultrasonic inspection apparatus according to the present invention.

In this embodiment, as shown in FIG. 30, an inspection object (not shown) is present in water, and an underwater swimming robot 74 which is an example of an underwater swimming mechanism as a transport means.
The fiber exit optical systems 25 and 30 are transported to the vicinity of the inspection position for inspection. The underwater swimming robot 74 is provided with a surveillance TV camera 56,
The monitoring TV camera 56 can monitor the inspection work underwater.

Further, the optical systems 25 and 3 for emitting the fiber are provided.
0 can be finely moved by the drive motor 75, and after the underwater swimming robot 74 roughly performs the positioning, the drive motor 75 is driven, whereby the fiber emission optical system 25 is moved.
And 30 can be positioned in a detailed inspection position.

Further, in order to cope with the case where the flow in the water is fast, in this embodiment, the fixing mechanism 7 is attached to the peripheral structural member 76.
By fixing the underwater swimming robot 74 using 7,
A fixed point inspection can also be performed. Then, for example, when a crack or the like is detected, and it is continuously evaluated and monitored, the vicinity of the crack detected by the laser beam EL is marked, and the position is detected by the monitoring TV camera 56, so that each time it is detected. The same crack can always be measured in the inspection.

[Seventeenth Embodiment] FIG. 31 is a block diagram showing a seventeenth embodiment of the laser ultrasonic inspection apparatus according to the present invention.

In this embodiment, as shown in FIG. 31, a plurality of fiber emitting optical systems 25 and 30 are installed near a predetermined inspection position on the material 3 to be inspected in advance, and a fiber emitting optical system to be used is used. By switching the system, it is possible to inspect a plurality of locations with one set of the laser ultrasonic inspection apparatus.

Therefore, the material to be inspected 3 (as shown in FIG.
The plurality of inspection positions are not limited to the case where they are set to one inspection target material 3).
a, 25b, 25c ... and 30a, 30b, 30c ...
And optical fibers 24a, 24 connected to them, respectively.
., and 29a, 29b, 29c..., and the other ends of these optical fibers are provided with optical fiber connectors 78a, 78b, 78c.
c ... is installed. Naturally, they may be fixed to the material 3 to be inspected or other peripheral members by a suitable fixing jig (not shown) so that the irradiation light condensing condition such as the focal point does not change.

On the other hand, the optical fiber 24 for transmitting the laser beam EL is connected to an optical fiber connector 78 as a detachable member.
The optical fiber 29 for transmitting the measuring light ML is provided with an optical fiber connector 79 as a detachable member.

With this configuration, the optical fiber connectors 78 and 79 are connected to the optical fiber connector 7 respectively.
8a, 78b, 78c ... and 79a, 79b, 79c
By appropriately switching the connection targets for..., It is possible to realize a laser ultrasonic inspection apparatus capable of inspecting a plurality of points with one apparatus.

[Eighteenth Embodiment] FIG. 32 is a block diagram showing an eighteenth embodiment of the laser ultrasonic inspection apparatus according to the present invention.

In the present embodiment, as shown in FIG. 32, in addition to the configuration of the seventeenth embodiment, pipes, containers, equipment, and structural materials in which the material to be inspected 3 is shielded by the heat insulating material 80 are used. Emission optical systems 25a, 25b, 25c ... and 3
Are provided inside the inspection target material 3 and the heat insulating material 80. The optical fibers 24a, 24b, 24c... And 29a, 29b, 29
c ... penetrate the heat insulating material 80 and are guided to the outside using a dedicated penetration or its structural boundary. Optical fiber connectors 78a, 78 installed at the other end of the optical fiber
b, 78c... and 79a, 79b, 79c. Naturally, they may be fixed to the material 3 to be inspected or other peripheral members by a suitable fixing jig (not shown) so that the irradiation light condensing condition such as the focal point does not change. With this configuration, it is possible to realize a laser ultrasonic inspection apparatus capable of performing an inspection on the inside of a shield.

In the present embodiment, the material to be inspected 3 may be a pipe, a container, equipment, or a structural material installed in a narrow portion. In this case, the optical fibers 24a, 24b, 2
4c ... and 29a, 29b, 29c ... penetrate the heat insulating material 80 and are led to the remote part where the inspection device is installed.

As described above, according to the thirteenth to eighteenth embodiments, an effective inspection can be performed by being configured in combination with the transport mechanism and its control mechanism.

[Nineteenth Embodiment] FIG. 33 is a block diagram showing a nineteenth embodiment of the laser ultrasonic inspection apparatus according to the present invention.

In the present embodiment, as shown in FIG. 33, an object to be inspected is a substance 3 on which a substance such as rust or paint, which deteriorates the propagation or transmission of ultrasonic waves, such as rust or paint, is adhered. This is an effective configuration in the case.

Laser light CL oscillated from laser light source 82
A technique for removing the adhering matter 81 by scanning in the direction D (laser cleaning technique) is described in, for example, Japanese Patent Laid-Open No. 7-22.
This is known from Japanese Patent No. 5300. Since the laser beam CL also excites ultrasonic waves in the process of removing the adhering matter 81, it is possible to perform a laser ultrasonic inspection while cleaning the surface by combining this with the receiving optical system 5 and the like. In particular, since only the fiber emission optical system 30 is installed at the tip of the existing laser cleaning device, the load on the device configuration is small, and not only cleaning but also inspection is performed without changing existing laser cleaning equipment. It is possible to realize a laser ultrasonic inspection apparatus capable of performing the above.

[Twentieth Embodiment] FIG. 34 is a block diagram showing a twentieth embodiment of the laser ultrasonic inspection apparatus according to the present invention.

The present embodiment is effective when inspecting an object while improving the stress state on the surface of the material 3 to be inspected as shown in FIG. The technology for improving the surface stress of the material to be inspected 3 (laser peening technology) by scanning the laser beam PeL oscillated from the laser light source 83 in the azimuth D is described in, for example, the above-mentioned “Yuji Sano et.
cess and application of s
hook compression by nano-
second pulses of frequency
y-doubled Nd: YAG laser, "
Proc. of ALPHA'99 SPIE, O
Saka, November 1999 ".

This laser beam PeL also excites ultrasonic waves in the process of improving the stress state on the surface of the material 3 to be inspected.
By combining this with the receiving optical system 5 and the like, it becomes possible to perform laser ultrasonic inspection while improving surface stress. In particular, since only the fiber emitting optical system 30 is installed at the tip of the existing laser peening apparatus, the burden on the apparatus configuration is small, and the inspection can be performed not only for improving the stress but also for the inspection without changing the existing laser peening equipment. A practicable laser ultrasonic inspection apparatus can be realized.

[Twenty-First Embodiment] FIG. 35 is a block diagram showing a twenty-first embodiment of the laser ultrasonic inspection apparatus according to the present invention.

The present embodiment is an effective configuration for inspecting an object while analyzing the material of the inspection object 3 as shown in FIG. Laser light source 84 as pulse laser light source
Is irradiated with laser light BL oscillated from a laser beam to ablate a minute volume on the surface of the material 3 to be inspected, and the emitted light is condensed using a condensing optical system 85, and is then analyzed by an optical fiber 86 as a spectroscopic analysis as a precedent means. A method of analyzing the material composition by leading the light to the evaluation device 87 and performing spectral analysis is known as a laser breakdown spectral analysis technique.

Since the laser beam BL also excites ultrasonic waves in the process of causing the material to be inspected 3 to emit plasma, by combining this with the receiving optical system 5 or the like, laser ultrasonic inspection can be performed while analyzing the material composition. It is possible to do.

In this embodiment, in particular, the fiber output optical system 3 is attached to the tip of an existing laser breakdown spectrometer.
Since only 0 is installed, the burden on the device configuration is small,
It is possible to realize a laser ultrasonic inspection apparatus capable of performing not only material composition analysis but also inspection without changing existing laser breakdown spectroscopy equipment.

[Twenty-second Embodiment] FIG. 36 is a block diagram showing a twenty-second embodiment of the laser ultrasonic inspection apparatus according to the present invention.

This embodiment is an effective configuration for inspecting a crack or a material property of the material 3 to be inspected by paying attention to propagation of a surface wave component among ultrasonic waves excited by the laser beam EL.

Generally, the surface wave is rapidly attenuated when the liquid W adheres to the surface of the material 3 to be inspected. Therefore, when the material 3 to be inspected is placed in the liquid, a detectable surface wave signal is detected. There are issues such as the level drop.

Therefore, in this embodiment, as shown in FIG. 36, a compressor 88 and a pipe 89 connected to the compressor 88 and having a distal end disposed near the fiber output optical system 41 are installed to drive the compressor 88. Then, air Air is blown from the tip of the pipe 89 to the vicinity of the inspection point, and the ultrasonic transmission / reception point, that is, the irradiation position of the laser beam and the propagation path of the surface wave are replaced with a gas atmosphere. Therefore, the compressor 88 and the pipe 89 constitute local gas atmosphere generating means.

With this configuration, it is possible to observe a surface wave with little attenuation, and even if dust or the like is generated by the irradiation of the laser beam EL, the blown air Ai
There is an effect that dust or the like is scattered by r and does not easily become a scatterer on the propagation path of the laser beam.

[Modification of the Twenty-second Embodiment] FIG. 37 is a block diagram showing a modification of the twenty-second embodiment of the laser ultrasonic inspection apparatus according to the present invention.

In this modification, as shown in FIG. 37, the region where the irradiation position of the laser beam and the propagation path of the surface wave are replaced with a gas atmosphere is covered with a container 90 as a local gas atmosphere generating means.

Therefore, when it is difficult to keep the laser beam irradiation position of the material 3 to be inspected and the propagation path of the surface wave in a gaseous atmosphere, it is difficult to maintain the region in the container 90 as in this modification. Covering makes it possible to more easily maintain the replacement state.

[23rd Embodiment] FIG. 38 is a block diagram showing a 23rd embodiment of the laser ultrasonic inspection apparatus according to the present invention.

This embodiment is an effective configuration for the inspection when the inspection target material 3 needs to prevent surface damage and heat input as much as possible. The ultrasonic excitation process using the laser beam EL has two types, a thermal strain mode and an ablation mode.

In general, in the thermal strain mode, no surface damage or thermal change in the material 3 to be inspected occurs, but in the ablation mode, evaporation of the surface layer and slight heat input occur.

In order to prevent this, in the present embodiment,
As shown in FIG. 38, by forming a protective film 91 on the surface of the material 3 to be inspected in advance and irradiating the protective film 91 with laser light EL, surface damage or heat input in the ablation mode can be suppressed. . As the protective film 91, a substance that efficiently absorbs the laser light EL is suitable and should be selected according to the wavelength and energy of the laser light EL. For example, fine particles such as colored liquid such as black ink or oil, colored powder, It may be a solid or powder.

[Twenty-fourth Embodiment] FIG. 39 is a block diagram showing a twenty-fourth embodiment of the laser ultrasonic inspection apparatus according to the present invention.

The present embodiment is an effective configuration for an inspection in which the material to be inspected 3 is installed remotely and requires detailed focusing of the measurement light ML which cannot be confirmed from the image of the monitoring TV camera or the like. is there. Light P reflected from the surface of the inspection material 3
L becomes maximum when the distance between the fiber output optical system 30 and the inspection target material 3 is optimized, and in this state, the detection sensitivity of the ultrasonic signal also becomes maximum. However, the photodetector 13
Is incident not only on the reflected light PL but also on the end face of each optical element, stray light, and the like, and the situation of the reflected light PL is not always clear.

Therefore, in this embodiment, as shown in FIG. 39, the shield plate driving device 93 is driven by a drive signal from the shield plate drive control device 92, thereby operating the shield plate 94 as return light confirmation means. By forming a state in which the measurement light ML does not reach the inspection target material 3, the return state of the reflected light PL can be confirmed from the output signal change of the photodetector 13 at that time.

The shielding plate 94 is preferably a scatterer of the measurement light ML and has a low reflectance. It is also effective to install the shielding plate 94 at an angle so as not to be orthogonal to the optical axis. In this case, the shielding plate 94 may be a mirror. Further, for example, as shown in FIG. 30, the fiber emission optical system 30 is previously mounted on the fine movement stage, and the fiber emission optical system 30 is located at a position where the change in the output signal of the photodetector 13 due to the operation of the shielding plate 94 is maximized. It is also possible to align the optical system 30.

[Twenty-fifth Embodiment] FIG. 40 is a block diagram showing a twenty-fifth embodiment of the laser ultrasonic inspection apparatus according to the present invention.

In the present embodiment, another inspection is effective in the case where the inspection target material 3 is installed remotely and the detailed focusing of the measurement light ML which cannot be confirmed from the image of the monitoring TV camera or the like is required. It is a structural example. The reflected light PL from the surface of the inspection target material 3 is transmitted from the fiber output optical system 30 to the inspection target material 3.
Is maximized when the distance is optimized, and in this state, the detection sensitivity of the ultrasonic signal also becomes maximum.

From the fiber output optical system 30 to the material to be inspected 3
Since the optimum value of the distance can be preliminarily estimated from the focal length of the fiber exit optical system 30, in this embodiment, a distance sensor 95 is provided at the tip of the fiber exit optical system 30 as shown in FIG. The fine movement control device 96 operates the fine movement stage 97 so that the distance measured by the distance sensor 95 becomes the optimum value estimated in advance, so that the measurement can always be performed under optimum reflection conditions.
The fine movement control device 96 and the fine movement stage 97 constitute a position adjusting means.

[Modification of Twenty-Fifth Embodiment] FIG. 41 is a block diagram showing a modification of the twenty-fifth embodiment of the laser ultrasonic inspection apparatus according to the present invention.

In this modification, as shown in FIG. 41, the distance between the fiber output optical system 30 and the inspection target material 3 is maintained at an optimum value. The distance fixing jig 98 is pressed against the inspection target material 3 by a spring mechanism or the like (not shown). This makes it possible to maintain the distance between the fiber emission optical system 30 and the inspection target material 3 at an optimum value with a simple configuration.

[0200]

As described above, according to the present invention, a laser beam for transmitting and receiving an ultrasonic wave is transmitted using an optical fiber, an irradiation optical system or an irradiation / condensing optical system. A laser ultrasonic inspection apparatus capable of efficiently inspecting a material to be inspected in a narrow portion without impairing remote non-contact properties can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of a laser ultrasonic inspection apparatus according to the present invention.

FIG. 2 is a block diagram showing a modified example of the first embodiment of the laser ultrasonic inspection apparatus according to the present invention.

FIG. 3 is an explanatory diagram showing the effect of the configuration of FIG. 2;

FIG. 4 is a block diagram showing a second embodiment of the laser ultrasonic inspection apparatus according to the present invention.

FIG. 5 is a block diagram showing a first modified example of the second embodiment of the laser ultrasonic inspection apparatus according to the present invention.

FIG. 6 is an explanatory diagram showing the effect of the configuration of FIG. 5;

FIG. 7 is a block diagram showing a second modification of the second embodiment of the laser ultrasonic inspection apparatus according to the present invention.

FIG. 8 is a block diagram showing a third embodiment of the laser ultrasonic inspection apparatus according to the present invention.

FIG. 9 is a block diagram showing a fourth embodiment of the laser ultrasonic inspection apparatus according to the present invention.

FIGS. 10A and 10B are explanatory views showing a fifth embodiment of the laser ultrasonic inspection apparatus according to the present invention.

FIG. 11 is an explanatory view showing a modification of the fifth embodiment of the laser ultrasonic inspection apparatus according to the present invention.

FIG. 12 is a block diagram showing a sixth embodiment of the laser ultrasonic inspection apparatus according to the present invention.

FIG. 13 is a block diagram showing a receiving optical system of a laser ultrasonic inspection apparatus according to a seventh embodiment of the present invention.

FIG. 14 is a configuration diagram showing a fiber incidence optical system of an eighth embodiment of the laser ultrasonic inspection apparatus according to the present invention.

FIG. 15 is a block diagram showing a ninth embodiment of the laser ultrasonic inspection apparatus according to the present invention.

FIG. 16 shows a tenth laser ultrasonic inspection apparatus according to the present invention.
FIG. 1 is a block diagram showing an embodiment.

FIG. 17 is an explanatory diagram showing signal processing using wavelet transform in the tenth embodiment.

FIG. 18 shows an eleventh embodiment of the laser ultrasonic inspection apparatus according to the present invention.
FIG. 1 is a block diagram showing an embodiment.

FIGS. 19A and 19B are explanatory diagrams showing display examples of a twelfth embodiment of the laser ultrasonic inspection apparatus according to the present invention.

FIGS. 20A and 20B are explanatory diagrams showing display examples when scanning is performed two-dimensionally.

FIGS. 21A and 21B are explanatory diagrams showing display examples when the same measurement result is three-dimensionally shown.

FIGS. 22A and 22B are explanatory diagrams showing an example in which attention is paid to a surface wave.

FIG. 23 is a thirteenth embodiment of the laser ultrasonic inspection apparatus according to the present invention.
FIG. 1 is a configuration diagram illustrating an embodiment.

FIG. 24 shows a thirteenth laser ultrasonic inspection apparatus according to the present invention.
FIG. 9 is a configuration diagram showing a first modification of the embodiment.

FIG. 25 is a thirteenth part of the laser ultrasonic inspection apparatus according to the present invention.
FIG. 9 is a configuration diagram showing a second modification of the embodiment.

FIG. 26 shows a fourteenth embodiment of the laser ultrasonic inspection apparatus according to the present invention.
FIG. 1 is a configuration diagram illustrating an embodiment.

FIG. 27 shows a fourteenth embodiment of the laser ultrasonic inspection apparatus according to the present invention.
FIG. 9 is a configuration diagram showing a first modification of the embodiment.

FIG. 28 shows a fourteenth embodiment of the laser ultrasonic inspection apparatus according to the present invention.
FIG. 9 is a configuration diagram showing a second modification of the embodiment.

FIGS. 29A and 29B are configuration diagrams showing a fifteenth embodiment of the laser ultrasonic inspection apparatus according to the present invention.

FIG. 30 shows a sixteenth embodiment of the laser ultrasonic inspection apparatus according to the present invention.
The perspective view showing an embodiment.

FIG. 31 shows a seventeenth embodiment of the laser ultrasonic inspection apparatus according to the present invention.
FIG. 1 is a block diagram showing an embodiment.

FIG. 32 shows an eighteenth laser ultrasonic inspection apparatus according to the present invention.
FIG. 1 is a block diagram showing an embodiment.

FIG. 33 shows a nineteenth embodiment of the laser ultrasonic inspection apparatus according to the present invention.
FIG. 1 is a block diagram showing an embodiment.

FIG. 34 shows a twentieth embodiment of the laser ultrasonic inspection apparatus according to the present invention.
FIG. 1 is a block diagram showing an embodiment.

FIG. 35 shows a 21st laser ultrasonic inspection apparatus according to the present invention.
FIG. 1 is a block diagram showing an embodiment.

FIG. 36 shows a 22nd laser ultrasonic inspection apparatus according to the present invention.
FIG. 1 is a block diagram showing an embodiment.

FIG. 37 shows a 22nd laser ultrasonic inspection apparatus according to the present invention.
FIG. 9 is a block diagram showing a modification of the embodiment.

FIG. 38 shows a 23rd laser ultrasonic inspection apparatus according to the present invention.
FIG. 1 is a block diagram showing an embodiment.

FIG. 39 shows a twenty-fourth laser ultrasonic inspection apparatus according to the present invention.
FIG. 1 is a block diagram showing an embodiment.

FIG. 40 shows a twenty-fifth laser ultrasonic inspection apparatus according to the present invention.
FIG. 1 is a block diagram showing an embodiment.

FIG. 41 shows a twenty-fifth laser ultrasonic inspection apparatus according to the present invention.
FIG. 9 is a block diagram showing a modification of the embodiment.

FIG. 42 is a block diagram showing a conventional laser ultrasonic inspection apparatus.

FIG. 43 is an explanatory view showing the operation of the Fabry-Perot resonator.

FIG. 44 is an explanatory view showing the operation of the Fabry-Perot resonator.

FIG. 45 is a block diagram showing another conventional laser ultrasonic inspection apparatus.

FIG. 46 is a block diagram showing still another conventional laser ultrasonic inspection apparatus.

[Explanation of symbols]

 Reference Signs List 1 laser light source (first laser light source) 2 optical system 3 material to be inspected 4 laser light source (second laser light source) 5 receiving optical system 6a to 6c 1/2 wavelength plate 7a to 7f polarization beam splitter 13 photodetector ( Signal conversion means) 14 Signal processing device 15 Display device 16 Evaluation device 17 Fabry-Perot resonator 18 Photodetector 19 Controller 20 Drive mechanism 21 Quarter wave plate 23 Fiber incidence optical system (first incidence optical system) ) 24 optical fiber (first optical fiber) 25 fiber emission optical system (irradiation optical system) 26 optical splitter 28 fiber incidence optical system (second incidence optical system) 29 optical fiber (second light) Fiber) 30 Fiber exit optical system (irradiation / condensing optical system) 31 Imaging optical system 32 Imaging optical system 34 Fiber bundle 35 Fiber exit optical system 36 Two-dimensional Array type photodetector 37 Optical system 38 Optical splitter (photosynthesis / branching means) 39 Optical system for fiber incidence (optical system for dual use) 40 Optical fiber (optical fiber for dual use) 41 Optical system for fiber emission (irradiation / collection for dual use) Optical optical system) 42 Narrow band optical filter 43a, 43b Window part with anti-reflection coating 44a, 44b Container 45a, 45b Medium 46 Concave lens 47 Micro lens array 48 Lens 49 Time gate 50 S / N ratio improving means 51a, 51b Drive mechanism 52 Rail 53 Trackless traveling vehicle 54 Inspection arm 55 Position detecting device 56 Monitoring TV camera 57a, 57b Communication device 58 Drive / control device 59 Track 60 Monorail traveling vehicle 61 Portable rail 62 Traveling vehicle 63 Reactor 64 Reactor internal structure 65 pulse light transmission device 67 furnace inspection robot 68 Tube 69 mobile robot 70 orbit 71 traveling carriage 72a, 72b irradiation mirror 73 waveguide 74 underwater swimming robot 75 drive motor 76 structural member 77 fixing mechanism 78, 78a to 78c optical fiber connector 79, 79a to 79c optical fiber connector 80 heat insulation Material 81 Attached object 82 Laser light source 83 Laser light source 84 Laser light source 85 Condensing optical system 86 Optical fiber 87 Spectral analysis / evaluation device 88 Compressor 89 Piping 90 Container 91 Protective film 92 Shield plate drive control device 93 Shield plate drive device 94 Shield Plate 95 Distance sensor 96 Fine movement control device 97 Fine movement stage 98 Distance fixing jig SP Signal processing device

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takahiro Miura 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Inside the Toshiba Yokohama Office (72) Inventor Shigehiko Mukai 8-six Shin-Sugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Inside the Toshiba Yokohama Office (72) Inventor Yuji Sano, 8-8 Shinsugita-cho, Isogo-ku, Yokohama, Kanagawa Prefecture Inside the Toshiba Yokohama Office (72) Tomoyuki Ito, 8-8 Shinsugita-cho, Isogo-ku, Yokohama, Kanagawa Prefecture Toshiba Corporation Inside the Yokohama Office (72) Katsuhiko Naruse, Inventor Katsuhiko 8-8 Shinsugita-cho, Isogo-ku, Yokohama, Kanagawa Prefecture Inside the Yokohama Office (72) Inventor Seiki Soramoto 8-8 Shin-Sugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Toshiba Yokohama Corporation In-house F-term (reference) 2G047 BA04 CA04 EA00 GD01

Claims (11)

[Claims] 1. A first laser light source for oscillating a first laser beam for generating an ultrasonic wave on a material to be inspected, and the material to be inspected for receiving an ultrasonic signal generated in the material to be inspected. A second laser light source that oscillates a second laser beam applied to the object, and a receiving optical system that optically detects information about the ultrasonic wave from a reflection component of the second laser beam on the surface of the inspection target material. And signal conversion means for converting an ultrasonic signal received by the receiving optical system into an electric signal,
A signal processing unit that performs signal processing on an output signal of the signal conversion unit and displays and records information related to the propagation of the ultrasonic wave, wherein the laser beam oscillated from the first laser light source is At least one optical fiber for transmitting to the vicinity of the material to be inspected, and an irradiation optical fiber provided at a tip of the optical fiber on the side of the material to be inspected, for irradiating the material to be inspected with the first laser beam under predetermined irradiation conditions. A laser ultrasonic inspection apparatus comprising an optical system. 2. A first laser light source for oscillating a first laser beam for generating an ultrasonic wave on a material to be inspected, and the material to be inspected for receiving an ultrasonic signal generated in the material to be inspected. A second laser light source that oscillates a second laser beam applied to the object, and a receiving optical system that optically detects information about the ultrasonic wave from a reflection component of the second laser beam on the surface of the inspection target material. And signal conversion means for converting an ultrasonic signal received by the receiving optical system into an electric signal,
A signal processing unit that performs signal processing on an output signal of the signal conversion unit and displays and records information related to the propagation of the ultrasonic wave, wherein the laser beam oscillated from the second laser light source is At least one optical fiber for transmitting the laser light emitted by the second laser light source to the vicinity of the inspection target material and transmitting a reflection component of the laser light on the surface of the inspection target material to the receiving optical system; A laser ultrasonic inspection apparatus, comprising: an irradiation / condensing optical system for irradiating / condensing a laser beam, provided at a tip of the fiber on the side of the material to be inspected. 3. A first laser light source for oscillating a first laser beam for generating an ultrasonic wave on a material to be inspected, and the material to be inspected for receiving an ultrasonic signal generated in the material to be inspected. A second laser light source that oscillates a second laser beam applied to the object, and a receiving optical system that optically detects information about the ultrasonic wave from a reflection component of the second laser beam on the surface of the inspection target material. And signal conversion means for converting an ultrasonic signal received by the receiving optical system into an electric signal,
A signal processing unit that performs signal processing on an output signal of the signal conversion unit and displays and records information on the propagation of the ultrasonic wave. At least one first optical fiber for transmitting a laser beam to the vicinity of the material to be inspected; and the first laser light provided at the tip of the first optical fiber on the material to be inspected side and the first laser light being transmitted to the material to be inspected. An irradiation optical system for irradiation under predetermined irradiation conditions, and a second laser light oscillated from the second laser light source is transmitted to the vicinity of the material to be inspected, and irradiated by the second laser light source. At least one second optical fiber for transmitting a reflection component of the second laser light on the surface of the material to be inspected to the receiving optical system; and a second optical fiber provided at a tip of the second optical fiber on the material to be inspected side. The laser ultrasonic inspection apparatus characterized by comprising a radiation-converging optical system for performing radiation-converging the second laser beam. 4. A first laser light source for oscillating a first laser beam for generating an ultrasonic wave on a material to be inspected, and the material to be inspected for receiving an ultrasonic signal generated in the material to be inspected. A second laser light source that oscillates a second laser beam applied to the object, and a receiving optical system that optically detects information about the ultrasonic wave from a reflection component of the second laser beam on the surface of the inspection target material. And signal conversion means for converting an ultrasonic signal received by the receiving optical system into an electric signal,
In the laser ultrasonic inspection apparatus having signal processing means for processing an output signal of the signal conversion means and displaying and recording information on the propagation of the ultrasonic wave, the first laser light and the second laser A light combining / branching means for superimposing light on the same optical axis, a dual-use incident optical system for receiving the first and second laser lights, respectively, and A dual-use optical fiber for transmitting to the vicinity, and transmitting a reflection component of the second laser light on the surface of the inspection target material to the receiving optical system; and a dual-use optical fiber installed at the end of the inspection target material side of the dual-use optical fiber. A dual-purpose irradiation / light-collecting optical system for irradiating the inspection object with the first and second laser beams under predetermined irradiation conditions, and condensing the reflection components thereof under predetermined light-condensing conditions. Was it The laser ultrasonic inspection apparatus characterized. 5. The laser ultrasonic inspection apparatus according to claim 1, wherein the first laser light source for generating ultrasonic waves on the material to be inspected performs pulse oscillation of Nd: YA.
A laser ultrasonic inspection apparatus, which is a G laser light source. 6. The laser ultrasonic inspection apparatus according to claim 1, wherein the second laser light source for irradiating the surface of the inspection target material and receiving an ultrasonic signal includes:
A laser ultrasonic inspection apparatus, which is a second harmonic light source of a continuously oscillating Nd: YAG laser. 7. The laser ultrasonic inspection apparatus according to claim 1, wherein an input / output section of the optical fiber is provided with anti-reflection means for reducing the amount of return light due to the reflection of the end face. Laser ultrasonic inspection equipment. 8. The laser ultrasonic inspection apparatus according to claim 1, wherein a receiving optical system for optically detecting information on ultrasonic waves is a Michelson interferometer, and A laser ultrasonic inspection apparatus, wherein an optical fiber for transmitting a reflection component on a surface of a material to be inspected to an optical system is a single mode optical fiber. 9. The laser ultrasonic inspection apparatus according to claim 1, wherein the receiving optical system for optically detecting information related to the ultrasonic wave is a Fabry-Perot optical meter. A laser ultrasonic inspection apparatus, wherein the optical fiber for transmitting the reflection component on the surface of the material to be inspected to the Perot optical meter is either a graded index optical fiber or a step index optical fiber. 10. The laser ultrasonic inspection apparatus according to claim 9, wherein the reference light for controlling the resonator of the Fabry-Perot optical meter has the same core diameter as the optical fiber transmitting the reflection component on the surface of the material to be inspected. A laser ultrasonic inspection apparatus which transmits through an optical fiber. 11. A focal point dispersive optical system according to claim 1, wherein said first laser light emitted from said first laser light source is incident on an optical fiber. A laser ultrasonic inspection apparatus, comprising: