JP2018179833A - Ultrasonic receiver, defect inspection device, ultrasonic reception method, defect inspection method, and method for manufacturing structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simultaneously measure ultrasonic signals at multiple points and realize high-accuracy inspection of a structure, etc., on the basis of simultaneously measured ultrasonic signals.SOLUTION: According to an embodiment, an ultrasonic receiver 100 comprises: a laser beam source 10 for exciting a laser beam with which to irradiate a test object 91; a laser beam dividing optical system 20 for dividing a laser beam 1 in order for two irradiation points 96a, 96b of the test object 91 to be irradiated; a reflected beam condensing optical system 30 for condensing and synthesizing each of divided reflected beams 3a, 3b of divided laser beams 2a, 2b with which the two irradiation points 96a, 96b are irradiated and outputting as a synthesized reflected beam 4; interference measuring means 40 for chronologically outputting a signal obtained by interference measurement of the synthesized reflected beam 4 as an ultrasonic signal; and signal processing means 50 for selecting an ultrasonic signal that corresponds to an evaluation time window from among ultrasonic signals 97 constituted so as to allow an evaluation time window defined by an evaluation time window start point and an evaluation time window end point to be set.SELECTED DRAWING: Figure 1

Description

  Embodiments of the present invention relate to an ultrasonic receiving apparatus, a defect inspection apparatus, an ultrasonic receiving method, a defect inspection method, and a method of manufacturing a structure using the same.

  Conventionally, the application of ultrasonic measurement method using laser light, so-called laser light ultrasonic method, has been limited to laboratory measurement, but a high-power receiving laser light source or an interference measurement device resistant to rough surfaces is used. Application to industrial sites is rapidly advancing as it is being developed. Its greatest strength lies in its ability to measure without contact. For this reason, an object that is difficult to touch, such as fragile, small, narrow, or high temperature, which can not be touched easily, or an object whose performance may be affected by the contact, or water or the like because of its size Application to an object that can not be immersed in the medium is expected.

  On the other hand, due to the property of using laser light interference measurement for ultrasonic wave reception, the device involved in ultrasonic wave reception becomes large and expensive, and for example, it is realistic to increase the number of channels easily as in phased array ultrasonic wave. It is difficult. Therefore, operations such as increasing the number of channels in a pseudo manner by scanning the reception position of ultrasonic waves, and making the number of channels increase without increasing the cost of the device are required, which has been a hindrance to widespread use. .

Patent No. 4665000 Patent No. 5721985

C. B. Scruby and L. E. Drain, Laser Ultrasonic: Techniques and Applications (Adam Hilger, Bristol, 1990)

  In order to solve the above-described problems, attempts have been made to increase the number of laser light / ultrasound reception channels without increasing the number of light sources and the like. For example, there is known a technology for realizing an ultrasonic wave receiving function at a plurality of points using a single laser light source and an interferometer by providing a plurality of irradiation mechanisms and switching means connecting them. However, in this case, it is necessary to provide switching means and distribute light to each irradiation point, so that the mechanism becomes complicated, and ultrasonic measurement is performed at only one reception point for one ultrasonic excitation. It is a problem that complete simultaneous measurement can not be performed because it is impossible.

  In addition, it is suggested that the laser light irradiation points be made plural and returned to a single interferometer and the measurement can be performed simultaneously. A plurality of laser light irradiation points can be provided without increasing the number of light sources if a branch is provided on a single light source. However, it is understood that there is no specificity about the configuration of the interferometer that realizes simultaneous measurement, and that it is a description of the premise that signals obtained at each independent receiving point are handled independently. Therefore, it is necessary to construct a signal recording system in which switching means such as a multiplexer is combined with an AD converter having the number of channels equal to the number of reception points or an AD converter having the number of channels less than the reception points.

  Based on these techniques, the embodiment of the present invention can simultaneously measure ultrasonic signals at a plurality of points, and realize high-precision inspection of a structure or the like based on the simultaneously measured ultrasonic signals. With the goal.

  In order to achieve the above-described object, an ultrasonic receiving apparatus according to the present embodiment comprises a laser light source for exciting a laser beam to be irradiated to a subject to be inspected, and a first irradiation point and a second irradiation point of the subject to be inspected. Laser beam splitting optical system that splits the laser beam so that it can be irradiated, and the reflected light of the laser beam irradiated to the first irradiation point and the second irradiation point are respectively combined and combined and combined reflection Reflected light focusing optical system which outputs as light, interference measuring means which temporally outputs a signal obtained by performing interference measurement of the combined reflected light as an ultrasonic wave signal, an evaluation time window starting point which is a time to be a starting point, A signal configured to be able to set an evaluation time window determined by an evaluation time window which is a time to be an end point, and selecting and evaluating the ultrasonic signal corresponding to the evaluation time window among the ultrasonic signals. Providing processing means And butterflies.

  Further, the defect inspection apparatus according to the present embodiment includes ultrasonic excitation means for exciting an ultrasonic wave in the inspection object, and the ultrasonic wave receiving apparatus of the above embodiment, and the signal processing unit is the inspection object. It is characterized in that it is configured to be able to evaluate the signal of the reflected ultrasonic wave of the ultrasonic wave generated due to the defect as the ultrasonic signal.

  Further, in the ultrasonic wave receiving method according to the present embodiment, the laser light to be irradiated to the inspection object is excited, and the laser light is divided into the first irradiation point and the second irradiation point of the inspection object and irradiated. And the reflected light of the laser beam irradiated to the first irradiation point and the second irradiation point respectively collected and synthesized as a synthetic reflected light, and a signal obtained by the interference measurement of the synthetic reflected light An evaluation time window which is output temporally as an ultrasonic wave signal and which is determined by an evaluation time window starting point which is a starting time and an evaluation time window end point which is an ending time is set, and the evaluation time window of the ultrasonic wave signals is set. And selecting and evaluating the ultrasonic signal corresponding to.

  Further, a defect inspection method according to the present embodiment is a defect inspection method for exciting an ultrasonic wave in an inspection object to carry out the ultrasonic wave receiving method of the above embodiment, wherein the ultrasonic signal is the inspection object It is a signal of the reflected ultrasonic wave of the said ultrasonic wave which generate | occur | produces by the defect of (4).

  In addition, the method for manufacturing a structure according to the present embodiment is characterized by including a preparation step of preparing the structure, and an inspection step of performing the defect inspection method of the above embodiment using the structure as an inspection object. I assume.

  According to the embodiment of the present invention, ultrasonic signals at a plurality of points can be simultaneously measured, and high-precision inspection of a structure or the like can be realized based on the simultaneously measured ultrasonic signals.

It is a block diagram showing composition of an ultrasonic wave receiving device concerning a 1st embodiment. It is a flow figure showing the procedure of the ultrasonic wave receiving method concerning a 1st embodiment. It is a block diagram which shows notionally a system at the time of using a branch type fiber as a laser beam division means of an ultrasonic receiving device concerning a 1st embodiment. It is sectional drawing which shows notionally the system | structure at the time of using a branch type | mold fiber for the division | segmentation reflected light joining means of the ultrasonic receiving apparatus based on 1st Embodiment. It is sectional drawing which shows notionally the system at the time of using a half mirror for the laser beam division means of the ultrasonic receiving device concerning a 1st embodiment. It is sectional drawing which shows notionally the system | structure at the time of using a half mirror for the division | segmentation reflected light confluence | merging means of the ultrasonic receiving apparatus based on 1st Embodiment. It is sectional drawing which shows notionally the system at the time of using a polarization beam splitter for the laser beam division means of the ultrasonic receiver concerning a 1st embodiment. FIG. 5 is a cross-sectional view conceptually showing a system in which a polarization beam splitter is used as a split reflection light combining means of the ultrasonic receiving apparatus according to the first embodiment. It is sectional drawing which shows notionally the system in the case of sharing one part by the laser beam division | segmentation optical system of the ultrasonic receiving apparatus which concerns on 1st Embodiment, and a reflected light condensing optical system. It is sectional drawing which shows the detection position of the ultrasound receiving apparatus which concerns on 1st Embodiment. It is a graph which shows the time change of the ultrasonic signal in the case of the detection position shown in FIG. FIG. 6 is a cross-sectional view showing another detection position of the ultrasonic receiving apparatus according to the first embodiment. It is a graph which shows the time change of the ultrasonic signal in the case of the detection position shown in FIG. It is sectional drawing which shows the detection position of the ultrasound receiving apparatus which concerns on 1st Embodiment. It is a graph which shows the time change of the ultrasonic signal in the case of the detection position shown in FIG. It is sectional drawing for demonstrating the relationship between the evaluation time window by the ultrasonic receiving apparatus which concerns on 1st Embodiment, and the propagation path of an ultrasonic wave. It is a graph which shows the time change of the ultrasonic signal in the case of the detection position shown in FIG. It is sectional drawing which shows the detection position of the ultrasound receiving apparatus which concerns on 1st Embodiment. It is a graph which shows the time change of the ultrasonic signal in the case of the detection position shown in FIG. It is sectional drawing which shows the detection position of the ultrasound receiving apparatus which concerns on 1st Embodiment. It is a graph which shows the time change of the ultrasonic signal in the case of the detection position shown in FIG. It is sectional drawing which shows the 1st example which performs measurement of a different detection objective in parallel by the ultrasound receiver which concerns on 1st Embodiment. It is a perspective view which shows the 2nd example which performs measurement of a different detection objective in parallel by the ultrasonic receiver which concerns on 1st Embodiment. It is a block diagram showing composition of an ultrasonic wave receiving device concerning a 2nd embodiment. It is sectional drawing which shows the example of the detection position of the ultrasound receiving apparatus which concerns on 2nd Embodiment. It is a graph which shows the time change of the ultrasonic signal in the case of the detection position shown in FIG. It is sectional drawing which shows the other example of the detection position of the ultrasound receiving apparatus which concerns on 2nd Embodiment. It is a graph which shows the time change of the ultrasonic signal in the case of the detection position shown in FIG. It is a flowchart which shows the procedure of the manufacturing method of the structure which concerns on 3rd Embodiment. In the manufacturing method of the structure concerning a 3rd embodiment, it is a sectional view showing the state at the time of setting the irradiation point of the division | segmentation laser beam by an ultrasonic receiving device to the different position of the same base material part. In the manufacturing method of the structure concerning a 3rd embodiment, it is a graph which shows the example of the time change of the ultrasonic wave at the time of performing surface inspection and volume inspection simultaneously. In the manufacturing method of the structure concerning a 3rd embodiment, it is a notional sectional view explaining propagation of a mode conversion wave originating in defects. In the manufacturing method of the structure concerning a 3rd embodiment, it is a sectional view showing the state at the time of setting the irradiation point of the division | segmentation laser beam by an ultrasonic receiving device over different members. In the manufacturing method of the structure concerning a 3rd embodiment, it is a sectional view showing the state where surface inspection and volume inspection are performed simultaneously after the end of welding. In the manufacturing method of the structure concerning a 3rd embodiment, it is the 1st graph which shows the example of the time change of the ultrasonic wave for explaining the waveform discrimination of the ultrasonic wave. In the manufacturing method of the structure concerning a 3rd embodiment, it is the 2nd graph which shows the example of the time change of the ultrasonic wave for explaining the waveform distinction of an ultrasonic wave.

  Hereinafter, with reference to the drawings, an ultrasonic receiving apparatus, a defect inspection apparatus, an ultrasonic receiving method, and a method of manufacturing a structure according to an embodiment of the present invention will be described. Here, parts that are the same as or similar to each other are given the same reference numerals, and duplicate explanations are omitted.

First Embodiment
FIG. 1 is a block diagram showing the configuration of the ultrasound receiving apparatus according to the first embodiment. The ultrasonic wave receiving apparatus 100 measures the ultrasonic wave that has propagated through the subject 91 by laser light irradiation.

  The ultrasonic wave receiving apparatus 100 includes a laser light source 10, a laser beam splitting optical system 20, a reflected light focusing optical system 30, an interference measuring unit 40, a signal processing unit 50, a display unit 60, and an input unit 80.

  The laser light source 10 is a laser light source for irradiating a laser beam 1 for receiving an ultrasonic wave. Examples of laser light used for the laser light source 10 include Nd: YAG laser light, CO 2 laser light, Er: YAG laser light, titanium sapphire laser light, alexandrite laser light, ruby laser light, dye (die) laser light and excimer laser light Etc. Moreover, it does not limit to these. The laser light source 10 uses a continuous wave or a pulse wave.

  The laser beam 1 generated by the laser light source 10 is transferred to the laser beam splitting optical system 20 by the laser beam transmitting means 11. The laser light transmission means 11 is made of a lens, a mirror, a fiber, or a combination thereof, and it may be space transmission or fiber transmission to transmit the respective laser beams over a long distance.

  The laser beam splitting optical system 20 splits the laser beam 1 into two or more divided laser beams 2a and 2b, and a plurality of laser beam transporting means 22a for transporting the split laser beams 2a and 2b. , 22b, and a plurality of divided laser beam irradiation means 23a, 23b for irradiating each of the divided laser beams 2a, 2b.

One or more laser beam dividing means 21 are provided between the laser light source 10 and the divided laser beam irradiating means 23a and 23b. For example, the laser beam splitting means 21 may not use polarized light such as a branched fiber or a half mirror, or may use polarized light such as a polarization beam splitter. In any case, the laser light 1 can be branched at an arbitrary light amount ratio by controlling the transmittance and the polarization.

  The plurality of split laser beam irradiation units 23a and 23b are provided at different positions so as to irradiate different split laser beams 2a and 2b to different irradiation points 96a and 96b (generally referred to as irradiation points 96) on the inspection object 91. It is arranged.

  The divided laser beam irradiation units 23a and 23b have an optical system for forming an arbitrary spot shape when the divided laser beams 2a and 2b are irradiated to the respective irradiation points 96a and 96b. The spot shape may be a point, a line, an ellipse, a ring (donut), a crescent, etc., but other shapes may be used. The optical system may be a lens or a mirror or a combination thereof, and an aspheric mirror or an aspheric lens may be used.

  The reflected light focusing optical system 30 includes split reflected light focusing means 31 a and 31 b for focusing the split reflected lights 3 a and 3 b, which are the reflected lights of the split laser beam 2 irradiated to the inspection object 91 respectively. Split light transmission means 32a and 32b for transmitting the split reflected lights 3a and 3b, which are the reflected lights of the first and second split reflected lights 3a and 3b, into a single transmission system to form one combined reflected light 4 The reflected light combining means 33 and the reflected light transmission means 34 for transmitting the combined reflected light 4 are provided.

  The split reflected light focusing means 31a and 31b focus on the split reflected lights 3a and 3b respectively irradiated and reflected at the irradiation points 96a and 96b. The reflected light transmission means 32 a, 32 b transmit the collected divided reflected lights 3 a, 3 b to the divided reflected light joining means 33.

  Similarly to the laser beam splitting means 21, the split reflected light combining means 33 may not use polarized light such as a branched fiber or a half mirror, or may use polarized light like a polarization beam splitter.

  Each of the laser beam transmission means may be space transmission or fiber transmission as described above, but the split laser beams 2a and 2b irradiated to the test object 91 from the split laser light irradiation means 23a and 23b and the test object All of the split reflected lights 3a and 3b that are reflected by the body 91 and reach the split reflected light focusing means 31a and 31b need to be space transmission.

  The interference measurement means 40 extracts the ultrasonic signal 97 from the wavelength change amount of the combined reflected light 4. The split laser beams 2a and 2b irradiated to the irradiation points 96a and 96b of the split laser beams 2a and 2b are reflected or scattered by the test object 91. When the ultrasonic wave reaches the irradiation points 96a and 96b of the split laser beams 2a and 2b and the surface is vibrating, the split reflection lights 3a and 3b are super It becomes a laser beam containing a sound wave signal component. When interference measurement is performed on the synthetic reflected light 4 including the ultrasonic signal component, the phase modulation amount is output as a change of the voltage signal, and this becomes the ultrasonic signal 97.

  Examples of the interference measurement means 40 include Michelson interferometers, homodyne interferometers, heterodyne interferometers, Fizeau interferometers, Mach-Zehnder interferometers, Fabry-Perot interferometers, and photorefractive interferometers, and the like, of course. Laser light interferometers are also conceivable. A knife edge method can also be considered as a method other than the interference measurement.

  The signal processing means 50 has an AD converter 51 for digitizing the ultrasonic signal 97, an evaluation time window definition means 52, an irradiation point definition means 53, and a signal evaluation means 54.

  The evaluation time window definition means 52 uses the shape and sound velocity of the test object 91 to transmit ultrasonic waves from the desired measurement range of the test object 91 to the irradiation points 96a and 96b irradiated with the split laser beam 2 Are respectively calculated, and evaluation time window starting points 62a and 62b of evaluation time windows 61a and 61b and evaluation time window end points 63a and 63b are respectively determined.

  The irradiation point definition means 53 sets the positions of the irradiation points 96a and 96b on the inspection object 91 by the plurality of divided laser light irradiation means 23a and 23b. Specifically, for the irradiation points 96a and 96b, the divided laser beam irradiation points are defined by performing back calculation so that the evaluation time window start points 62a and 62b or the evaluation time window end points 63a and 63b do not coincide.

  The signal evaluation means 54 extracts at least one or more of amplitude, frequency or phase information from the ultrasonic signal 97 in the evaluation time windows 61a and 61b.

  The display means 60 displays the ultrasonic signal 97 as a visible graph. The block diagram shown in FIG. 1 is an example, and each function may be divided into separate devices or integrated.

  The defect inspection apparatus 200 has an ultrasonic excitation means 94 for exciting an ultrasonic wave at an ultrasonic excitation point 95 and an ultrasonic receiving apparatus 100 in order to inspect a defect of the inspection object 91.

  FIG. 2 is a flow chart showing the procedure of the ultrasonic wave receiving method according to the first embodiment.

  First, laser light for reception is excited (step S01). Specifically, the laser light source 10 is activated to make it possible to irradiate the laser light 1 which is a laser light for reception. At this point of time, it is assumed that ultrasonic waves are generated from the ultrasonic excitation point 95 by the ultrasonic excitation means 94, for example, in the test object 91.

  Next, the irradiation point definition means 53 defines the first irradiation point 96a and the second irradiation point 96b (step S02). In addition, the irradiation point 96 is not limited to two places, Three or more places may be sufficient.

  Next, the laser beam 1 is divided into the split laser beams 2a and 2b, and the split laser beams 2a and 2b are respectively irradiated to the first irradiation point 96a and the second irradiation point 96b (step S03). That is, the laser beam splitting means 21 splits the laser beam 1 into split laser beams 2a and 2b, and the split laser beam irradiating means 23a and 23b irradiate the first irradiation point 96a and the second irradiation point 96b, respectively.

  Next, the reflected light is condensed at the first irradiation point 96a and the second irradiation point 96b and is combined with the synthetic reflected light 4 (step S04). That is, at each of the first irradiation point 96a and the second irradiation point 96b, the divided reflected light condensing means 31a, 31b condenses the reflected light, that is, the divided reflected light 3a, 3b and collects the divided reflected light The split reflected light combining means 33 combines 3a and 3b into the combined reflected light 4 (step S04).

  Next, the combined reflected light 4 is measured by interference and output over time (step S05). That is, the interference measurement means 40 measures the interference of the combined reflected light 4 and outputs it as an ultrasonic wave signal 97 to the signal processing means 50, and the display means 60 displays the ultrasonic wave signal 97 over time.

  Further, the evaluation time window definition means 52 sets an evaluation time window (step S06). That is, the evaluation time window definition means 52 determines the evaluation time window 61a which is determined by the evaluation time window start points 62a and 62b which are times at which the evaluation target time area starts, and the evaluation time window end points 63a and 63b which are times at which the evaluation time points are end points. , 61b. The evaluation time window definition unit 52 corresponds to the ultrasonic wave emitted from the ultrasonic excitation unit 94 based on the propagation time from the ultrasonic excitation unit 94 to the irradiation points 96 a and 96 b evaluated first in the evaluation point definition unit 53. Assume a time width in which the ultrasonic signal 97 is generated. Specifically, the evaluation time window definition means 52 sets the evaluation time window start points 62a and 62b and the evaluation time window end point 63a with a margin such as two cycles of the ultrasonic signal 97 in the time width at which the ultrasonic signal 97 is generated. , 63b etc. As a result, basically, the evaluation time windows 61a and 61b defined by the evaluation time window start points 62a and 62b and the evaluation time window end points 63a and 63b can cover the generation time width of the ultrasonic signal 97.

  Step S06 needs to be before step S07, but it does not matter whether it is before or after step S02 to step S05.

  Next, the ultrasonic signal within the evaluation time window is selected and evaluated (step S07). That is, the signal evaluation means 54 extracts at least one or more of amplitude, frequency or phase information from the ultrasonic signal 97 in the evaluation time windows 61a and 61b, and based on the ultrasonic signal 97, information on the defect 98 etc. The information on the subject 91 to be inspected is secured.

  Next, it is determined whether the evaluation of the ultrasonic signal 97 is possible (step S08). That is, the signal evaluation means 54 tries to secure information on the inspected object 91 such as information on the defect 98 (FIG. 30) based on the ultrasonic wave signal 97, but the first irradiation point 96a and the second irradiation In some cases, the position of the point 96 b is inappropriate and the ultrasonic signal 97 can not discriminate the signal. In such a case, the signal evaluation means 54 determines that the evaluation of the ultrasonic signal 97 is not possible.

  If it is determined in step S08 that the evaluation of the ultrasound signal 97 is not possible (NO in step S08), steps S02 to S08 are repeated. In step S08, when it is determined that the evaluation of the ultrasonic signal 97 is possible (YES in step S08), the reception of the ultrasonic wave by the ultrasonic receiving apparatus 100 ends.

  FIG. 3 shows a system in the case where a branched fiber is used as the laser beam splitting means of the ultrasonic receiving apparatus according to the first embodiment, and FIG. 4 uses a branched fiber as the split reflected light combining means. It is sectional drawing which shows the system of a case notionally.

  The branched fiber is typically, for example, a bundle fiber composed of a plurality of cores, and the strength can be adjusted by the distribution number. The fibers in the laser beam transmission means 11 are divided into respective fibers in the laser beam transmission means 22 a and 22 b in the laser beam splitting means 21.

  As a result, the laser light 1 emitted from the laser light source 10 is transmitted by the laser light transmission means 11 and then divided into respective fibers in the laser light transmission means 22 a and 22 b which are divided in the laser light division means 21. Be done.

  The split laser beam 2a transmitted by the laser beam transmission means 22a is irradiated onto the inspection object 91 by the split laser light irradiation means 23a. Similarly, the split laser beam 2b transmitted by the laser beam transmission means 22b is irradiated onto the inspection object 91 by the split laser light irradiation means 23b.

  The split reflected light 3a irradiated to the inspection object 91 by the split laser beam irradiation unit 23a and reflected is collected by the split reflected light focusing unit 31a, transmitted by the reflected light transmission unit 32a, and transmitted to the split reflected light merging unit 33. To reach. Similarly, the split reflected light 3b irradiated to the inspection object 91 by the split laser beam irradiation means 23b and reflected is collected by the split reflected light focusing means 31b, transmitted by the reflected light transmission means 32b, and the split reflected light merging The means 33 are reached.

  The divided reflected lights 3a and 3b transmitted by the reflected light transmission means 32a and the reflected light transmission means 32b are merged by the divided reflected light joining means 33, transmitted as the combined reflected light 4 by the reflected light transmission means 34, and interference measurement It leads to means 40.

  FIG. 5 shows a system in the case of using a half mirror as the laser beam splitting means of the ultrasonic receiving apparatus according to the first embodiment, and FIG. 6 shows a case in which the half mirror is used in the split reflected light combining means. It is sectional drawing which shows a system notionally.

  When a half mirror is used, when discussed under ideal conditions, in the system shown in FIG. 5, the laser beam 1 having an output of 100% from the beginning is split by the laser beam splitting means 21 and outputs 50% each. The divided laser beams 2a and 2b are obtained. That is, for example, when the transmissivity of the half mirror 21a of the laser beam splitting means 21 is 50%, 50% of the laser beam 1 reaching the half mirror 21a is transmitted and divided laser beam irradiating means as the split laser beam 2a You will reach 23a. The remaining 50% of the laser beam 1 reaching the half mirror 21a is reflected to reach the mirror 21b as the split laser beam 2b, and the entire amount is reflected to reach the split laser beam irradiation means 23b. In the half mirror 21a, the transmittance and the reflectance are not limited to 50% each. For example, one of them may have a large ratio such as 40% and 60%.

  When the reflectance of the test object 91 is 100%, the entire amount is reflected. The 50% output split reflected lights 3a and 3b reflected respectively are collected by the split reflected light focusing means 31a and 31b, respectively, joined by the split reflected light combining means 33, and the system shown in FIG. Then, the interference measuring means 40 is reached.

  Specifically, the split reflected light 3a irradiated by the split laser beam irradiating means 23a and reflected and collected by the split reflected light focusing means 31a reaches the half mirror 33a of the split reflected light combining means 33, The split reflected light 3 a of 50%, ie, 25% of the intensity of the original laser beam 1 is transmitted and transmitted to the interference measurement means 40 by the reflected light transmission means 34. Also, the divided reflected light 3b irradiated by the other divided laser beam irradiating means 23b and reflected and condensed on the divided reflected light collecting means 31b reaches the mirror 33b of the divided reflected light combining means 33, and the entire amount is reflected It reaches half mirror 33a after being done. The half reflected light 3b of 50% of the half mirror 33a, that is, 25% of the original laser light 1 is reflected and transmitted to the interference measuring means 40 by the reflected light transmitting means.

  As described above, the combined reflected light 4 after merging reaches the interference measurement means 40 with an intensity of at most 50% with respect to the original laser light 1.

  FIG. 7 is a cross sectional view conceptually showing a system in the case where a polarization beam splitter is used as a laser beam splitting means, and FIG. 8 is a system in which a polarization beam splitter is used as a split reflected light combining means.

  Now, with respect to the plane of incidence to the optical system, let the components whose polarization directions are perpendicular to each other be P wave and S wave, respectively. The components of the laser light 1 originally emitted from the laser light source 10 are mixed. As shown in FIG. 7, when using a polarization beam splitter for the laser beam splitting optical system 20, the laser beam 1 can be split into the respective components. For example, as shown in FIG. 7, a polarization beam splitter that transmits P waves and reflects S waves is used. Alternatively, a polarization beam splitter that transmits the S wave and reflects the P wave may be used.

  First, the laser beam 1 in which the P wave and the S wave are mixed reaches the polarization beam splitter 21 c of the laser beam splitting means 21. Here, the polarization beam splitter 21c transmits the P wave and reflects the S wave.

  The P wave transmitted through the entire polarization beam splitter 21 c is transmitted by the laser light transmission means 22 a as a separate laser light 2 a of P wave component alone, reaches the divided laser light irradiation means 23 a, and the first of the test object 91 The irradiation point 96a is irradiated. Also, the single S wave component reflected by the polarization beam splitter 21c is totally reflected by the mirror 21b as the split laser beam 2b, transmitted by the laser beam transmission means 22b, and reaches the split laser light irradiation means 23b, The second irradiation point 96 b of the test body 91 is irradiated.

  The divided reflected light 3a of the P wave component alone caused by the irradiation to the first irradiation point 96a is collected by the divided reflected light collecting means 31a and then transmitted as a single P wave component by the reflected light transmission means 32a, The light beam reaches the polarization beam splitter 33 c of the split reflection light merging means 33. The entire divided reflected light 3 a of the P wave component alone that has reached the polarization beam splitter 33 c is transmitted through the reflected light transmission unit 34 to the interference measurement unit 40.

  The split reflected light 3b of the S wave component alone collected by the other split reflected light focusing means 31b is sent to the mirror 33b in the split reflected light combining means 33, and the entire amount is reflected. The entire amount is reflected and sent to the interference measurement means 40 by the reflected light transmission means 34.

  As described above, the light is transmitted to the interference measurement means 40 as the combined reflected light 4 in which the S wave and the P wave are mixed by passing through the divided reflected light combining means 33.

  At this time, when it is desired to align the polarization direction of the reflected laser light, for example, one λ / 2 wavelength plate or two λ / 4 wavelength plates are inserted in the path of P wave or S wave alone, and the polarization direction is 90 By rotating the reflection division laser beam as a half mirror while rotating it by a certain degree, it is also possible to obtain, for example, a reflected light which is in phase with only the S wave.

  In the above configuration, a polarization beam splitter may be used in the forward pass, and a fiber branch may be used in the return pass, for example.

  FIG. 9 is a cross-sectional view conceptually showing a system in which a part is shared by the laser beam splitting optical system and the reflected light focusing optical system of the ultrasonic receiving apparatus according to the first embodiment. In the configuration shown in FIG. 9, the polarization beam splitter 21c of the laser beam splitting means 21 has the characteristics of P wave transmission and S wave reflection. The polarization beam splitter 21d provided in the middle of the laser beam transmission means 22a of the laser beam splitting optical system 20 also has the characteristics of P wave transmission and S wave reflection. The polarization beam splitter 21e provided in the middle of the laser light transmission means 22b of the laser light splitting optical system 20 has the characteristics of P wave reflection and S wave transmission. Furthermore, the polarization beam splitter 33c provided in the split reflected light combining means 33 has the characteristics of P wave transmission and S wave reflection.

  Of the laser beam 1 emitted from the laser light source 10 and reaching the polarization beam splitter 21c of the laser beam splitting means 21, the P wave component passes through the polarization beam splitter 21c, the entire S wave component is reflected, and the mirror 21b further reflect.

  The entire split laser beam 2a of the P wave component alone transmitted through the polarization beam splitter 21c is further transmitted through the polarization beam splitter 21d provided on the path of the laser beam transmission means 22a, and reaches the λ / 4 wavelength plate 21f. Do. When the split laser beam 2a of the P wave component alone passes through the λ / 4 wavelength plate 21f, the polarization is rotated by 90 degrees, and becomes a split laser beam 2a in a circular polarization state in which the P wave component and the S wave component are mixed. The object to be inspected 91 is irradiated by the divided laser light irradiation means 23a.

  On the other hand, the split laser beam 2b of the S wave component alone reflected by the polarization beam splitter 21c and further reflected by the mirror 21b is further transmitted through the polarization beam splitter 21e provided on the path of the laser beam transmission means 22b. / 4 wavelength plate 21 g is reached. When the split laser beam 2b of the S wave component alone passes through the λ / 4 wavelength plate 21g, the polarization is rotated by 90 degrees, and becomes a split laser beam 2b in a circular polarization state in which the P wave component and the S wave component are mixed. The object to be inspected 91 is irradiated by the divided laser light irradiation means 23b.

  The split laser beam 2a of one circularly polarized light emitted to the test object 91 is reflected by the test object 91, and is collected by the split reflection light focusing means 31a as the split reflection light 3a. Here, the split laser beam irradiation means 23a and the split reflection light focusing means 31a may be the same. The divided reflected light 3a is rotated by 90 degrees in the λ / 4 wavelength plate 21f, which is also used as the reflected light transmission means 32a, and becomes the divided reflected light 3a of the S wave component alone.

  The divided reflected light 3 a which is the S wave component alone is totally reflected by the polarization beam splitter 21 d and reaches the polarization beam splitter 33 c of the divided reflected light combining means 33. The split reflected light 3 a of the S wave component alone is totally reflected by the polarization beam splitter 33 c and transmitted to the interference measurement means 40 by the reflected light transmission means 34.

  On the other hand, the other divided laser beam 2b of the circularly polarized light emitted to the object to be inspected 91 is reflected by the object to be inspected 91 and condensed as the divided reflected light 3b by the divided reflected light focusing means 31b. Here, the divided laser beam irradiation unit 23b and the divided reflected light focusing unit 31b may be the same. The split reflected light 3b is rotated by 90 degrees in the λ / 4 wavelength plate 21g which is also used as the reflected light transmission means 32b, and becomes split reflected light 3b of the P wave component alone. The divided reflected light 3 b which is the P wave component alone is totally reflected by the polarization beam splitter 21 e and reaches the mirror 33 b of the divided reflected light combining means 33. The split laser beam 3b of the P wave component alone is totally reflected by the mirror 33b, and then reaches the polarization beam splitter 33c. The split reflection light 3 b of the P wave component alone is transmitted through the polarization beam splitter 33 c and transmitted to the interference measurement means 40 by the reflection light transmission means 34.

  The split reflection light merging means 33 may be combined with a means that does not use a polarization beam splitter as described above.

  FIG. 10 is a cross-sectional view showing the detection position of the ultrasonic receiving apparatus. FIG. 11 is a graph showing temporal changes of the ultrasonic signal in the case of the detection position shown in FIG.

  As shown in FIG. 10, ultrasonic waves are emitted from the ultrasonic excitation point 95 of the subject 91 by the ultrasonic excitation means 94. In this system, a case is shown where the first irradiation point 96a of the inspection object 91 is irradiated with the split laser beam 2a. The ultrasonic signal 97 obtained by the interference measurement means 40 shown in FIG. 10 is displayed as shown in FIG.

  In FIG. 11, the evaluation time window 61 is adjusted to the ultrasonic signal 97a. Specifically, it is detected in response to the ultrasonic wave emitted from the ultrasonic excitation point 95 in the measurement range 64 which is a time domain sandwiched by the evaluation time window starting point 62 and the evaluation time window end point 63 in the time axis direction. An ultrasound signal 97a is shown.

  FIG. 12 is a cross-sectional view showing another detection position of the ultrasonic receiving apparatus. Further, FIG. 13 is a graph showing temporal changes of the ultrasonic signal in the case of the detection position shown in FIG.

  As shown in FIG. 12, ultrasonic waves are emitted from the ultrasonic excitation point 95 of the subject 91 by the ultrasonic excitation means 94. In this system, the case where the second irradiation point 96b of the inspection object 91 is irradiated with the laser light is shown. The ultrasonic signal 97 which is a portion of the received wave of the ultrasonic signal 97 obtained by the interference measurement means 40 shown in FIG. 12 is displayed as shown in FIG.

  In FIG. 13, the evaluation time window 61 is matched to the ultrasonic signal 97b. Specifically, it is detected in response to the ultrasonic wave emitted from the ultrasonic excitation point 95 in the measurement range 64 which is a time domain sandwiched by the evaluation time window starting point 62 and the evaluation time window end point 63 in the time axis direction. An ultrasound signal 97b is shown.

  As shown in FIGS. 11 and 13, the relative positions of the first irradiation point 96a and the second irradiation point 96b, which are the irradiation points of the split laser beams 2a and 2b, and the ultrasonic excitation point 95, and the propagation. The intensity and time position of the peak of the obtained waveform are different depending on the mode difference, such as whether the ultrasonic wave is a surface wave or a volume wave.

  FIG. 14 is a cross-sectional view showing the detection position of the ultrasonic receiving apparatus, and shows the case where there are two detection positions. That is, the divided laser beams 2a and 2b are applied to the first irradiation point 96a and the second irradiation point 96b, respectively. Further, FIG. 15 is a graph showing temporal changes of the ultrasonic signal in the case of the detection position shown in FIG. The ultrasonic signal 97a from the ultrasonic excitation point 95 to the first irradiation point 96a and the ultrasonic signal 97b from the ultrasonic excitation point 95 to the second irradiation point 96b are shown. In FIG. 15, the evaluation time window 61 is adjusted to the ultrasonic signal 97a which is a first received waveform.

  Here, the ultrasonic signal 97a and the ultrasonic signal 97b have distinctly different propagation times. As described above, the two waves of the ultrasonic signal 97a and the ultrasonic signal 97b, which are clearly transmitted with different times, can be discriminated even if they are combined into one waveform as shown in FIG. That is, since the distances from the ultrasonic excitation point 95 to the first irradiation point 96a and the second irradiation point 96b of the split laser beams 2a and 2b are different from each other, time differences occur and measurement is performed.

  The evaluation time window definition means 52 of the signal processing means 50 defines the evaluation time window 61 by the evaluation time window starting point 62 and the evaluation time window end point 63. The signal evaluation means 54 of the signal processing means 50 has a function of extracting at least one or more of amplitude, frequency or phase information from the ultrasonic signal 97 within the range.

  Here, the amplitude is not only the width of the maximum value and the minimum value of the wave having the maximum peak, but when there are a plurality of waves, the width of each maximum value and the minimum value may be extracted. In addition, it is also possible to acquire not only the peak but also the amplitude information (maximum, minimum, RMS value, etc.) of the noise that becomes the background. The frequency information may have not only a typical analysis method such as fast Fourier transform but also a function of wavelet analysis, or a time window for further analysis in the evaluation time window to further limit the frequency analysis range. May be provided.

  The phase information includes the maximum and minimum peak time positions of the desired waveform, the zero cross point, the half width, and the like, and may be other information. Further, the signal evaluation unit 54 has a signal control function such as a frequency filter or averaging to simplify the evaluation of the above information, a display unit such as a PC monitor, a mouse or a keyboard so that the user can easily use it. It may be combined with an input means such as a touch panel.

  As described above, according to the relative distance between the ultrasonic excitation point 95 in the inspection object 91 and the first irradiation point 96a and the second irradiation point 96b of the split laser beams 2a and 2b, the number of the split laser beams 2a The arrival time of the ultrasonic wave differs between the irradiation point 96a of 1 and the second irradiation point 96b of the split laser beam 2b.

  If information on the speed of sound and part of the shape of the inspection object 91 is obtained, the ultrasonic signal 97a is a priori derived from the first irradiation point 96a and the second irradiation point 96b of the split laser beams 2a and 2b. You will have time to arrive. Therefore, in the evaluation time window definition means 52, it becomes possible to set the evaluation time window 61 in accordance with the irradiation point of each of the divided laser beams with the time as a standard.

  FIG. 16 is a cross-sectional view for explaining the relationship between the evaluation time window by the ultrasonic receiving apparatus and the propagation path of the ultrasonic wave. FIG. 17 is a graph showing temporal changes of the ultrasonic signal in the case of the detection position shown in FIG.

  An area with the inspection object 91 is defined as a measurement area 91a, and a certain time earlier by a certain margin from the propagation time at which the response can be obtained at the fastest from the measurement area 91a is defined as the evaluation time window starting point 62 of the evaluation time window 61 The evaluation time window end point 63 of the evaluation time window 61 may be defined as a delay time which is a certain margin late from the propagation time from the region where the response takes the longest time. That is, the evaluation time window start point 62 and the evaluation time window end point 63 are defined in the direction in which the measurement range 64 becomes wider. Each allowance is set based on the experience value and the like.

  FIG. 18 is a cross-sectional view showing a detection position of the ultrasonic receiving apparatus according to the first embodiment. FIG. 19 is a graph showing temporal changes of the ultrasonic signal in the case of the detection position shown in FIG.

  As shown in FIG. 18, the distances from the ultrasonic excitation point 95 at which the ultrasonic wave is excited by the ultrasonic excitation means 94 to the first irradiation point 96a and the second irradiation point 96b are substantially equal. As a result, the evaluation time of each of the evaluation time window 61a for the ultrasonic signal 97a from the first irradiation point 96a and the evaluation time window 61b for the ultrasonic signal 97b from the second irradiation point 96b The window start point 62a and the evaluation time window start point 62b, or the respective evaluation time window end points 63a and the evaluation time window end points 63b almost coincide with each other.

  Thus, when the evaluation time window starting points 62a and 62b or the evaluation time window end points 63a and 63b of the evaluation time windows 61a and 61b coincide with one another for the respective irradiation points of the divided laser beams, the irradiation point definition means 53 Divides the propagation time from the ultrasonic excitation point 95 to the first irradiation point 96a and the second irradiation point 96b so that the evaluation time window start points 62a and 62b or the evaluation time window end points 63a and 63b do not overlap It has a function of defining an irradiation point 96b of the laser beam 2b.

  FIG. 20 is a cross-sectional view showing a detection position of the ultrasonic receiving apparatus according to the first embodiment.

  FIG. 21 is a graph showing temporal changes in ultrasonic signals in the case of the detection position shown in FIG. In FIG. 21, the arrival time of the ultrasonic signal 97a and the arrival time of the ultrasonic signal 97b are different, and there is a time relationship in which the evaluation time window 61a and the evaluation time window 61b do not overlap. The irradiation point definition means 53 calculates how much the position of the second irradiation point 96 b should be changed in order to achieve this state. The calculated result is displayed on the display means 60.

  Below, two usage examples of the ultrasonic receiving apparatus 100 by this embodiment are shown.

  FIG. 22 is a cross-sectional view showing a first example in which measurement for different detection purposes is performed in parallel by the ultrasonic receiving apparatus according to the first embodiment.

  The first irradiation point 96 a is on the opposite side of the ultrasonic excitation point 95 and the subject 91. As a result, since the ultrasonic wave measured at the first irradiation point 96a has been transmitted from the ultrasonic excitation point 95 to the inside of the inspected object 91, the inspected object 91 can be obtained by grasping the propagation speed. It is in the state of measuring the board thickness.

  On the other hand, the ultrasonic wave measured at the second irradiation point 96 b has propagated from the ultrasonic excitation point 95 on the surface of the test object 91. As a result, a defect 98 occurring on the surface is simultaneously detected.

  As described above, while the thickness measurement is performed in the transmission arrangement, flaw detection can be performed simultaneously.

  FIG. 23 is a perspective view showing a second example of performing measurement for different detection purposes in parallel by the ultrasonic receiving apparatus according to the first embodiment. It is measurement in the state where steels of different plate thicknesses are flowing in two rolling steelmaking lines.

  There is a first irradiation point 96a which is an irradiation point of the split laser beam 2a in the steel material which is the first inspection object 91g flowing on one rolling steelmaking line. In addition, a second irradiation point 96b, which is an irradiation point of the split laser beam 2b, is present on the steel material which is the second inspection object 91h flowing on the other extended steel line.

  The split reflected lights 3a and 3b reflected by each reach the interference measurement means 40, and ultrasonic signals 97a and 97b for each are obtained and evaluated. As a result, it is possible to simultaneously measure the thickness of each of the first test subject 91g and the second test subject 91h, and it is possible to expect improvement in quality and efficiency of measurement with less resources.

  Usually, it is a phenomenon to avoid that information on multiple measurement points is mixed in one waveform, but in the present embodiment, as described above, the evaluation time window 61 and the irradiation points 96a and 96b of the divided laser beams 2a and 2b, respectively. By managing in cooperation with the coordinates of {circle around (1)}, it is possible to individually extract information on a plurality of measurement points in one waveform. This makes it possible to measure a plurality of points without adding an important signal recording system such as a light source, an interferometer, or a channel of an AD converter.

Second Embodiment
FIG. 24 is a block diagram showing the configuration of the ultrasound receiving apparatus according to the second embodiment. This embodiment is a modification of the first embodiment. The ultrasound receiving apparatus 100 according to the present embodiment further includes irradiation point position adjustment means. The irradiation point position adjusting means adjusts the position or relative position of each of the first irradiation point 96a and / or the second irradiation point 96b. A specific example of the irradiation point position adjustment means is a scanning means 71 as shown in FIG. The scanning means 71 moves and drives the divided laser beam irradiation means 23b and the divided reflected light focusing means 31b in a predetermined direction and a predetermined distance so as to scan the second irradiation point 96b. The scanning means 71 may also scan the first irradiation point 96a or all the irradiation points. Also, the ultrasonic excitation means 94 may be moved to scan the ultrasonic excitation point 95.

  The scanning means 71 may be anything that is generally called an automatic stage driven by pulses or servomotors and may be moved by automatic control. The scanning means 71 may have a function of feeding back not only scanning but also scanning position information.

  The evaluation time window definition means 52 calculates the ultrasonic wave propagation time sequentially based on the coordinates of the irradiation point 96b of the split laser beam 2b which changes due to the movement drive by the scanning means 71, and evaluates these tracking positions. It further has a function of defining an evaluation time window start point 62 and an evaluation time window end point 63 of the time window 61 respectively.

  FIG. 25 is a cross-sectional view showing an example of detection positions of the ultrasonic wave receiving apparatus. FIG. 26 is a graph showing temporal changes of the ultrasonic signal in the case of the detection position shown in FIG.

  FIG. 25 shows a case where the second irradiation point 96b, which is the irradiation point of the split laser light 2b, is moved by the scanning means 71 as 96b1, 96b2 and 96b3, for example. In the case of the first ultrasonic signal 97 a and the second ultrasonic signal 97 b 1, their generation times are close to each other so that they can not be easily shared with each other. By changing the ultrasonic wave propagation time to each of the first irradiation point 96a and the second irradiation point 96b by the scanning means 71, as in the second ultrasonic signal 97b2 or 97b3, the first point The ultrasonic signals 97a can be distinguished from each other.

  FIG. 27 is a cross-sectional view showing another example of the detection position of the ultrasonic receiving apparatus. Moreover, FIG. 28 is a graph which shows the time change of the ultrasonic wave signal in the case of the detection position shown in FIG.

  FIG. 27 shows a case where ultrasonic waves of different modes, such as surface waves and longitudinal waves, are measured at each irradiation point 96, for example. Here, when the position of the first irradiation point 96a is changed from 96a1 to 96a2, the ultrasonic wave propagation time is different in the speed of sound for each mode of the ultrasonic wave, and the result is as shown in FIG.

  The volume wave (longitudinal wave) is a path indicated by VL1 when the position of the first irradiation point 96a is 96a1, and a path indicated by VL2 when the position of the first irradiation point 96a is 96a2. . That is, the propagation distance is increased by the difference between the path VL2 and the path VL1.

  On the other hand, the surface wave (transverse wave) is a path indicated by SL1 when the position of the first irradiation point 96a is 96a1, and a path indicated by SL2 when the position of the first irradiation point 96a is 96a2. Become. That is, the propagation distance increases by the difference between the path SL2 and the path SL1.

  In FIG. 28, the ultrasonic wave 97V1 caused by the volume wave when the position of the first irradiation point 96a is 96a1, and the ultrasonic wave 97V2 due to the volume wave when the position of the first irradiation point 96a is 96a2. The difference between the occurrence times is taken as ΔTV. In addition, the generation time of the ultrasonic wave 97S1 caused by the surface wave when the position of the first irradiation point 96a is 96a1 and the ultrasonic wave 97S2 caused by the surface wave when the position of the first irradiation point 96a is 96a2 Let the difference be ΔTS.

  The volume wave (longitudinal wave) has a higher propagation velocity, ie, the speed of sound, than the surface wave (transverse wave). As a result, with respect to the increase of the propagation distance due to the change of the position of the first irradiation point 96a, the change of the propagation time of the ultrasonic wave is larger than the ΔTV in the case of the volume wave (longitudinal wave) The case of ΔTS is larger. That is, discrimination between ultrasonic waves 97V1 and 97V2 caused by volume waves and ultrasonic waves 97S1 and 97S2 caused by surface waves is possible.

  By using the scanning means in this manner, it becomes easy to extract the target signal from the ultrasonic signal having a plurality of peaks.

Third Embodiment
FIG. 29 is a flowchart showing the procedure of the method of manufacturing a structure according to the third embodiment. This embodiment is an example in the case where any one or a combination of the first embodiment and the second embodiment is used as a test object. In particular, in the present embodiment, the case where the structure is a joining member formed by joining two members will be described below as an example. The structure is not limited to the bonding member, and various kinds of internal defect inspection can be performed using the ultrasonic receiving apparatus and the ultrasonic receiving method of the first embodiment and the second embodiment. It can be an object of

  First, a first member 99a (FIG. 30) and a second member (FIG. 30) 99b which will constitute a structure are prepared, grooves are formed in each, and groove alignment is performed (step S11). Next, welding of a predetermined number of layers is performed (step S12). By welding a predetermined number of layers between the groove of the first member 99a and the second member 99b in step S12, the welded portions as the first member 99a, the second member 99b and the joint portion 92 are joined. It becomes a member (structure) (preparation step). After this preparation step, a defect inspection in the welding process is performed (step S13: inspection step). In the inspection in the welding process, information on the thickness of the joint can also be acquired in parallel with the detection of the defect 98 as described later.

  Here, the predetermined number of layers may be one or plural. If the predetermined number of layers is small, the number of weld inspections increases. Also, if the predetermined number of times is large, the scale of repair when the defect 98 (FIG. 30) is confirmed increases. Therefore, the predetermined number of layers may be determined in consideration of both. Also, the predetermined number of layers may be changed sequentially.

  As a result of the defect inspection in step S13, it is determined whether or not the defect 98 is detected (step S14). If it is determined that the defect 98 has been detected (YES in step S14), re-implementation of welding is performed with the defect including the defect 98 (step S15).

  If it is determined that the defect 98 has not been detected (NO in step S14), it is determined whether the process has been completed for all layers (step S16). If it is determined that all layers have not been completed (NO in step S16), steps S12 to S16 are repeated. If it is determined that all layers have been completed (YES in step S16), a defect inspection in the finished state is performed (step S17). At this stage, the bonding member 99 (FIG. 34) is the inspection object 91 (FIG. 34). Although not shown, if there is a defect in the final layer or surface in this inspection, repair will be performed.

  FIG. 30 is a cross-sectional view showing a state in which the irradiation points of the split laser light by the ultrasonic receiving apparatus are set at different positions of the same base material in the method of manufacturing a structure according to the third embodiment.

  The bonding member 99 (FIG. 34) is composed of a base portion 93a of the first member 99a, a base portion 93b of the second member 99b, and a bonding portion 92. The material of the base members 93a and 93b is not limited in terms of application of the present embodiment, as long as sound propagates and can be joined. For example, steel materials and non-ferrous metal materials such as carbon steel and stainless steel, non-ferrous metal materials, ceramic materials, polymer materials such as resins and living bodies, composite fiber reinforcement materials such as GFRP, or the like may be used.

  The bonding portion 92 is formed of a fusion or a filler of the base material portions 93a and 93b. The bonding method may be any method such as friction stir welding or brazing as well as general welding, in which the base material portions 93a and 93b are in close contact with each other or between the solvent and the base material portions 93a and 93b. In the present embodiment, the case where the manufacturing of the joining member 99 is performed by butt welding of thick plates will be described as a representative example. In the manufacturing process of the bonding member 99 described below, the test object 91 is the one in the bonding process.

  In the case shown in FIG. 30, the first irradiation point 96a is set on the beveled surface of the second member 99b, and the second irradiation point 96b is set on the surface of the same second member 99b. Also, the ultrasonic excitation point 95 is taken as the surface of the final layer of the joint 92.

  After the ultrasonic waves emitted from the ultrasonic excitation point 95 pass through the inside of the joint 92, a part thereof is at the end opposite to the ultrasonic excitation point 95 in the joint 92, that is, at the surface of the back wave. It reflects and propagates as a volume wave in the base material portion 93b of the second member 99b. The other part propagates as a surface wave on the beveled surface of the second member 99b.

  The ultrasonic waves reaching the first irradiation point 96 a are mainly surface waves propagating through the bevel surface. Further, the ultrasonic waves reaching the second irradiation point 96b are mainly volume waves propagating in the base material portion 93b. Each of the waves is affected by the presence of the defect 98 at the bonding portion 92, and therefore, from the split reflected light 3a, 3b from each of the first irradiation point 96a and the second irradiation point 96b, the defect 98 is related. It is possible to acquire ultrasonic waves containing information.

  FIG. 31 is a graph showing an example of a time change of ultrasonic waves when surface inspection and volume inspection are simultaneously performed in the method of manufacturing a structure according to the third embodiment. That is, it is an example of the measurement result in the system of FIG.

  The ultrasonic signal 97 b corresponds to a volume wave that directly reaches the second irradiation point 96 b. The ultrasonic signal 97b represented by a solid line is a volume wave with high sound velocity, and shows an echo of the back wave depth. That is, the signal corresponds to the welding thickness of the joint. In addition, the ultrasonic signal 97a1 corresponds to a surface wave that directly reaches the first irradiation point 96a. Low sound velocity surface waves are received later than volume waves. The ultrasonic signal 97a2 corresponds to a mode conversion wave derived from the defect 98 and converted from a volume wave to a surface wave.

  FIG. 32 is a conceptual cross-sectional view for explaining propagation of a mode conversion wave derived from a defect in the method for manufacturing a structure according to the third embodiment.

  A part of the ultrasonic wave generated at the ultrasonic excitation point 95 by the ultrasonic excitation means 94 propagates in the joint part 92, is reflected at the end (back wave part), and the base material part 93 is treated as a volume wave. It propagates and reaches the irradiation point 96. Since the velocity of the volume wave is large compared to the velocity of the surface wave, the ultrasonic signal 97 corresponding to this ultrasonic wave is detected earliest.

  Further, a part of the ultrasonic wave generated at the ultrasonic excitation point 95 by the ultrasonic excitation means 94 propagates as a surface wave along the groove surface and reaches the irradiation point 96. On the other hand, a part of the ultrasonic wave generated at the ultrasonic excitation point 95 propagates as a volume wave in the bonding portion 92 and is reflected by the defect 98. The reflected ultrasonic wave propagates in the joint portion 92 as a volume wave, and after reaching the joint portion 92 or the groove surface, it is changed to a surface wave, propagates on the groove surface, and reaches the irradiation point 96. As a result, as shown in FIG. 31, the ultrasonic signal 97a2 corresponding to the mode conversion wave derived from the defect 98 is delayed from the ultrasonic signal 97a1 corresponding to the surface wave directly reaching the first irradiation point 96a. It is detected.

  The ultrasonic signal 97a2 corresponding to the mode conversion wave derived from the defect excited by the principle as shown in FIG. 32 is observed a little later than the ultrasonic signal 97a1 corresponding to the directly excited surface wave. Can be distinguished, and plate thickness measurement and defect measurement can be performed simultaneously.

  As described above, by setting the first irradiation point 96a of the split laser beam 2a on the surface of the base material portion 93 and monitoring the penetration depth of the back wave, the second irradiation point 96b is formed as the beveled surface. By installing it in the above, it is also possible to receive an echo from the defect 98 generated just below the bead that is transmitted along the beveled surface.

  FIG. 33 is a cross-sectional view showing a state in which the irradiation point of the split laser light by the ultrasonic receiving apparatus is set across different members in the method of manufacturing a structure according to the third embodiment.

  In the case shown in FIG. 33, the first irradiation point 96a is set to the beveled surface of the first member 99a, and the second irradiation point 96b is set to the beveled surface of the second member 99b. Also, the ultrasonic excitation point 95 is taken as the surface of the final layer of the joint 92.

  After passing through the inside of the bonding portion 92, a part of the ultrasonic wave emitted from the ultrasonic excitation point 95 propagates as a surface wave on the beveled surface of the first member 99a and reaches the first irradiation point 96a. . The other part propagates as a surface wave on the beveled surface of the second member 99 b and reaches the second irradiation point 96 b.

  In this way, by irradiating across different members, for example, a defect that occurs at the position of the base material portion 93a of the first member 99a or the base material portion 93b of the second member 99b at a wide bonding portion of two or more passes. It also becomes possible to detect 98 without missing.

  The first irradiation point 96a and the second irradiation point 96b, which are the irradiation points 96 of the split laser beams 2a and 2b, may be set at different positions of the same member as shown in FIG. 30, for example. It may be set across different members as shown in FIG.

  Bonding always involves the risk of defects 98 occurring, and this embodiment makes it possible to detect them efficiently. For example, in butt welding as shown in FIG. 30 and FIG. 33, if a defect can be detected in the middle of welding, the time required for repair can be significantly reduced as compared with the case where a defect is found after the completion of welding.

  FIG. 34 is a cross-sectional view showing a state in which surface inspection and volume inspection are simultaneously performed after the end of welding in the method for manufacturing a structure in accordance with the third embodiment.

  In the case shown in FIG. 34, the first irradiation point 96a is set on the surface of the first member 99a, and the second irradiation point 96b is set on the surface of the second member 99b. Also, the ultrasonic excitation point 95 is set on the surface of the first member 99a. The ultrasonic excitation point 95 is located on the opposite side of the second irradiation point 96b with respect to the first irradiation point 96a.

  The ultrasonic waves emitted from the ultrasonic excitation point 95 pass through the joint 92 until reaching the second irradiation point 96 b. Therefore, a volume wave including information on the defect 98 a in the bonding portion 92 reaches the second irradiation point 96 b.

  On the other hand, the ultrasonic wave propagating on the surface of the base material portion 93a emitted from the ultrasonic excitation point 95 reaches the nearest first irradiation point 96a. In addition, part of the ultrasonic waves propagating on the surface of the base material portion 93a is reflected after reaching the surface defect 98b and reaches the first irradiation point 96a.

  FIG. 35 is a first graph showing an example of time change of ultrasonic waves for explaining the waveform discrimination of ultrasonic waves, and shows an example of inspection results in the system shown in FIG.

  In this case, the distance from the ultrasonic excitation point 95 to the first irradiation point 96a is shorter than the distance from the ultrasonic excitation point 95 to the second irradiation point 96b. Therefore, the ultrasonic signal 97a1 corresponding to the surface wave directly reaching the first irradiation point 96a precedes the ultrasonic signal 97b corresponding to the surface wave directly reaching the second irradiation point 96b. There is. In addition, the ultrasonic signal 97a2 corresponding to the surface wave arriving mode-converted from the defect 98 is generated with a slight delay to the ultrasonic signal 97a1 corresponding to the surface wave directly reaching the first irradiation point 96a.

  As shown in FIG. 35, even in the case of using surface waves having the same sound velocity, the waveform discrimination can be made by changing the relative position from the ultrasonic excitation point 95 and setting the irradiation point 96, so that the original Even a defect generated in the vicinity of the groove surface of each of the one member 99a and the second member 99b can be detected.

  FIG. 36 is a second graph showing an example of the time change of the ultrasonic wave for explaining the waveform discrimination of the ultrasonic wave.

  In the system shown in FIG. 34 described above, first, an ultrasonic signal 97a1 corresponding to a surface wave generated at the ultrasonic excitation point 95 and directly reaching the first irradiation point 96a is detected. Next, an ultrasonic signal 97 b 2 corresponding to the volume wave that is scattered from the intrinsic defect 98 a and reaches the irradiation point 96 b is detected. The ultrasonic signal 97b1 corresponding to the volume wave reflected from the bottom surface (surface of the back wave) of the bonding portion and reaching the irradiation point 96b is detected after the ultrasonic signal 97b2. Finally, the ultrasonic wave 97a2 corresponding to the surface wave reflected from the surface defect 98b is detected.

  The time series as described above are displayed in FIG. 36, and all the waves can be distinguished in time.

  Undercuts or delayed cracks that are likely to occur on the surface after completion of welding are detected by surface waves received by the first irradiation point 96a of the split laser beam 2a disposed on the same first member 99a as the ultrasonic excitation point 95. In addition, a volume wave received at the second irradiation point 96b disposed in the second member 99b different from the ultrasonic excitation point 95 is used to detect an inherent defect 98 such as a void or a fusion failure in the welded portion or the joint portion 92. It is possible to

  By appropriately setting the positions of the first irradiation point 96a, the second irradiation point 96b, and the ultrasonic excitation point 95 in this manner, it is possible to simultaneously perform surface inspection and volume inspection.

  A structure such as a bonding member manufactured by the above defect inspection can ensure sufficient quality without using a large-scale inspection apparatus. In addition, it is possible to suppress the increase in the manufacturing cost of the structure such as the bonding member.

Other Embodiments
While the embodiments of the present invention have been described above, the embodiments are presented as examples and are not intended to limit the scope of the invention.

  In addition, these embodiments can be implemented in other various forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the invention described in the claims and the equivalents thereof as well as included in the scope and the gist of the invention.

  DESCRIPTION OF SYMBOLS 1 laser light 2a 2b split laser light 3a 3b split reflected light 4 composite reflected light 10 laser light source 11 laser light transmission means 20 laser light splitting optical system 21 laser Light splitting means, 21a: half mirror, 21b: mirror, 21c, 21d, 21e: polarization beam splitter, 21f, 21g: λ / 4 wavelength plate, 22a, 22b: laser beam transmission means, 23a, 23b: split laser beam irradiation Means 30: reflected light focusing optical system 31a, 31b: split reflected light focusing means 32a, 32b: reflected light transmission means 33: split reflected light combining means 33a: half mirror, 33b: mirror, 33c ... Polarized beam splitter 34 Reflected light transmission means 40 Interference measurement means 50 Signal processing means 51 AD converter 52 Evaluation time window definition means 53 Irradiation point definition Stages 54 Signal evaluation means 60 Display means 61 61a 61b Evaluation time windows 62 62a 62b Evaluation time window starting point 63 63a 63b Evaluation time window end point 64 measurement range 71 scanning means (irradiation point position adjusting means) 80 input means 91 inspection object 91 a measurement area 91 g 91 h inspection object 92 joint portion 93 a 93 b base material portion 94 ... Ultrasonic excitation means, 95 ... Ultrasonic excitation point, 96, 96a, 96b ... Irradiation point, 97, 97a, 97b, 97b 1, 97b 2, 97b 3 ... Ultrasonic signal, 98, 98a, 98b ... Defects, 99 ... Bonding members 99a: first member 99b: second member 100: ultrasonic wave receiving device 200: defect inspection device

Claims (10)

A laser light source for exciting a laser beam to be irradiated to a subject to be inspected;
A laser beam splitting optical system that splits the laser beam so as to be capable of being irradiated to the first irradiation point and the second irradiation point of the inspection object;
A reflected light condensing optical system which condenses and synthesizes the reflected light of the laser light irradiated to the first irradiation point and the second irradiation point, respectively, and outputs as synthesized reflected light;
Interference measurement means for temporally outputting a signal obtained by performing interference measurement on the combined reflected light as an ultrasonic wave signal;
The ultrasonic wave signal corresponding to the evaluation time window of the ultrasonic wave signal is configured to be settable by an evaluation time window that is a starting time and an evaluation time window that is a time that is an end time. Signal processing means configured to be able to select and evaluate
An ultrasonic wave receiver comprising:   The ultrasonic receiving apparatus according to claim 1, wherein the signal processing means is configured to extract at least one of amplitude, frequency and phase information from the ultrasonic signal.   The evaluation time window starting point and the evaluation time window end point are respectively set based on the shape of the inspection object, the position of the first irradiation point, and the position of the second irradiation point. The ultrasonic wave receiving apparatus according to claim 1 or 2.   4. The irradiation point position adjusting means for adjusting the position of at least one of the first irradiation point and the second irradiation point is provided according to any one of claims 1 to 3. Ultrasound receiver.   5. The ultrasonic receiving apparatus according to claim 4, wherein the irradiation point position adjusting means scans at least one of the first irradiation point and the second irradiation point to be adjusted.   The inspection object includes a first member, a second member, and a joint portion joining the first member and the second member, the first irradiation point is on the first member, and the second irradiation point is The ultrasonic wave receiving apparatus according to any one of claims 1 to 5, wherein the irradiation point of (4) is on the second member. Ultrasonic excitation means for exciting ultrasonic waves in the subject;
An ultrasonic receiving apparatus according to any one of claims 1 to 6.
Equipped with
The defect inspection apparatus, wherein the signal processing means is configured to be able to evaluate a signal of a reflected ultrasonic wave of the ultrasonic wave generated at a defect of the inspection object as the ultrasonic signal. Excite the laser beam to be irradiated to the test object,
Dividing the laser beam into a first irradiation point and a second irradiation point of the inspection object;
The reflected lights of the laser beam irradiated to the first irradiation point and the second irradiation point are respectively collected and combined as a synthetic reflected light,
Outputting a signal obtained by performing interference measurement of the combined reflected light as an ultrasonic signal over time,
An evaluation time window which is a starting time and an evaluation time window which is determined by an evaluation time window end point which is an end time is set, and the ultrasonic wave signal corresponding to the evaluation time window is selected from the ultrasonic wave signals To evaluate
An ultrasonic wave receiving method characterized in that. 9. A defect inspection method for exciting an ultrasonic wave in an object to be inspected and carrying out the ultrasonic wave reception method according to claim 8;
The defect inspection method, wherein the ultrasonic signal is a signal of a reflected ultrasonic wave of the ultrasonic wave generated at a defect of the inspection object. Preparation steps to prepare the structure,
An inspection step of performing the defect inspection method according to claim 9 with the structure as an inspection object;
A method of manufacturing a structure comprising:

Images