Measuring device and measuring method

Abstract

This measurement device 20 comprises a control unit 13 that outputs electromagnetic waves from an electromagnetic wave output source 7 toward a sample 30 having a first layer 31 and a second layer 32 adjacent to each other and to which vibration is applied at a predetermined vibration frequency, receives reflected waves of the electromagnetic waves from a part 35 to be measured in the interface between the first layer 31 and the second layer 32, calculates the frequency or amplitude of vibration of the part 35 to be measured on the basis of the reflected waves, and measures the adhesive strength of the part 35 to be measured on the basis of the frequency or the amplitude of the vibration of the part 35 to be measured calculated on the basis of the reflected waves.

Description

Cross-reference of related applications

[0001] This application claims priority to Japanese Patent Application No. 2021-181510, filed in Japan on November 5, 2021, and the entire disclosure of the earlier application is incorporated herein by reference. [Technical Field]

[0002] This disclosure relates to a measuring device and a measuring method. [Background technology]

[0003] Non-destructive testing refers to inspection techniques that examine defects or deterioration in the interior or surface of a sample without destroying it. Patent Document 1 describes a technique for non-destructive testing to determine the adhesive strength between layers of a multilayer sample. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Patent No. 5684819 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, in the conventional configuration, there was room for improvement in the accuracy of measuring the adhesive strength between layers.

[0006] The purpose of this disclosure is to provide a measuring device and a measuring method that can improve the accuracy of measuring the adhesive strength between layers. [Means for solving the problem]

[0007] According to several embodiments of the measuring apparatus, a control unit is provided that outputs electromagnetic waves from an electromagnetic wave output source to a sample having adjacent first and second layers to which vibration is applied at a predetermined vibration frequency, receives reflected waves of the electromagnetic waves from the measurement target portion at the interface between the first and second layers, calculates the frequency or amplitude of the vibration of the measurement target portion based on the reflected waves, and measures the adhesive strength of the measurement target portion based on the frequency or amplitude of the vibration of the measurement target portion calculated based on the reflected waves. In this way, the measuring apparatus can measure the adhesive strength between layers with high accuracy because it acquires the frequency or amplitude of the vibration of the measurement target portion when the strength of the adhesive strength at the interface is manifested by vibration.

[0008] In one embodiment of the measuring device, the control unit measures the adhesive strength of the part to be measured based on the frequency spectrum of the vibration of the part to be measured in a frequency band that includes frequencies different from the vibration frequency. In this way, the measuring device can measure the adhesive strength of the part to be measured with even greater accuracy by referring to the frequency spectrum of the vibration of the part to be measured in a frequency band that includes frequencies different from the vibration frequency of the sample.

[0009] In a measuring device according to one embodiment, the control unit calculates the frequency or amplitude of the vibration of the part to be measured based on the reflected wave, based on Doppler measurement. By using Doppler measurement, the measuring device can reduce the influence of background noise and measure the adhesive strength of the part to be measured with even greater accuracy.

[0010] In a measuring device according to one embodiment, the control unit outputs a P-polarized laser from a laser light source to the sample at a Brewster angle as the electromagnetic wave. This eliminates the influence of reflected waves from the surface of the sample, and the measuring device can measure the adhesive strength of the part to be measured with even greater precision.

[0011] In a measuring device according to one embodiment, the control unit outputs electromagnetic waves to the sample to which vibration is applied at a first vibration frequency as a predetermined vibration frequency, and calculates a first frequency or first amplitude, which is the vibration frequency or amplitude of the part to be measured, based on the reflected waves of the electromagnetic waves from the part to be measured of the sample to which vibration is applied at the first vibration frequency, and outputs electromagnetic waves to the sample to which vibration is applied at a second vibration frequency as a predetermined vibration frequency, and calculates a second frequency or second amplitude, which is the vibration frequency or amplitude of the part to be measured, based on the reflected waves of the electromagnetic waves from the part to be measured of the sample to which vibration is applied at the second vibration frequency, and measures the adhesive strength of the part to be measured based on at least one of the first frequency and the second frequency, and the first amplitude and the second amplitude. Thus, the measuring device may utilize a combination of the frequency or amplitude of the reflected wave from the sample when vibration of a first vibration frequency is applied, and the frequency or amplitude of the reflected wave from the sample when vibration of a second vibration frequency is applied. Therefore, the measuring device can measure the adhesive strength of the part to be measured with even greater precision.

[0012] In a measuring device according to one embodiment, the control unit outputs electromagnetic waves toward each of a plurality of measurement target portions at the interface between the first layer and the second layer, receives reflected waves of the electromagnetic waves from each of the plurality of measurement target portions, analyzes the reflected waves from each of the plurality of measurement target portions to calculate the frequency or amplitude of the vibration of the measurement target portion, and measures the adhesive strength of the measurement target portion based on a comparison between the frequency or amplitude of the vibration of the measurement target portion and the average value of the frequency or amplitude of the vibration of the plurality of measurement target portions. In this way, the measuring device can further improve the measurement accuracy by measuring the frequency or amplitude of the vibration of a plurality of measurement target portions and measuring the adhesive strength of a certain measurement target portion based on a comparison with the average value of the frequency or amplitude of the vibration of the plurality of measurement target portions.

[0013] In the measuring device according to one embodiment, the control unit outputs electromagnetic waves of the first frequency from the first electromagnetic wave output source to the sample in which an additive that enhances the reflectivity of electromagnetic waves of the first frequency is applied to the second layer. As a result, the measuring device can receive a reflected wave with a high reflection intensity from the second layer, and can measure the adhesion strength of the measurement target portion existing at the interface between the first layer and the second layer with higher accuracy.

[0014] In the measuring device according to one embodiment, the control unit outputs electromagnetic waves of the second frequency from the second electromagnetic wave output source to the sample further having a third layer adjacent to the second layer to which an additive that enhances the reflectivity of electromagnetic waves of the second frequency is applied, receives the reflected wave of the electromagnetic waves of the second frequency from the measurement target portion at the interface between the second layer and the third layer, calculates the frequency or amplitude of the vibration of the measurement target portion at the interface between the second layer and the third layer based on the reflected wave of the second frequency, and measures the adhesion strength of the measurement target portion at the interface between the second layer and the third layer based on the frequency or amplitude of the vibration of the measurement target portion at the interface between the second layer and the third layer. As a result, the measuring device can receive a reflected wave with a high reflection intensity from the third layer, and can measure the adhesion strength of the measurement target portion existing at the interface between the second layer and the third layer with high accuracy.

[0015] In the measuring device according to one embodiment, the control unit outputs electromagnetic waves of the third frequency that are reflected by a specific foreign object from the third electromagnetic wave output source, and determines that the specific foreign object is present in the sample in response to receiving the reflected wave of the electromagnetic waves of the third frequency from the sample. Therefore, the measuring device can determine the presence or absence of foreign objects in the sample.

[0016] According to the measurement method according to some embodiments, a measurement method of a measurement device, wherein a control unit outputs electromagnetic waves from an electromagnetic wave output source to a sample having a first layer and a second layer adjacent to each other and vibrated at a predetermined vibration frequency; receiving a reflected wave of the electromagnetic wave from a measurement target portion at an interface between the first layer and the second layer; calculating a frequency or amplitude of vibration of the measurement target portion based on the reflected wave; and measuring an adhesive strength of the measurement target portion based on the frequency or the amplitude of vibration of the measurement target portion calculated based on the reflected wave. Thus, since the measurement method acquires the frequency or amplitude of vibration of the measurement target portion and measures the adhesive strength in a state where the strength of the adhesive strength at the interface is surfaced by vibration, it is possible to measure the adhesive strength between layers with high accuracy.

Advantages of the Invention

[0017] According to an embodiment of the present disclosure, it is possible to improve the measurement accuracy of the adhesive strength between layers.

Brief Description of the Drawings

[0018] [Figure 1] It is a diagram showing a schematic configuration of a measurement system including a measurement device according to an embodiment. [Figure 2] It is a flowchart showing an example of a measurement procedure by the measurement device of FIG. 1. [Figure 3] It is a diagram schematically showing a state in which a laser is output at a Brewster angle from the measurement device of FIG. 1 to a sample. [Figure 4A] It is a diagram schematically showing a state in which a laser is reflected from a sample including an adherend to which an additive is applied. [Figure 4B] It is a diagram schematically showing a state in which a laser is reflected from a sample including an adherend to which an additive is applied. [Figure 4C] It is a diagram schematically showing a state in which a laser is reflected from a sample including an adherend to which an additive is applied.

Embodiments for Carrying Out the Invention

[0019] <Comparative Example> The comparative example system described in Patent Document 1 outputs electromagnetic radiation to a multilayer sample and determines the adhesive strength between layers of the multilayer sample by analyzing the electromagnetic radiation reflected by the sample or transmitted through the sample. The comparative example system includes a transmitter that outputs electromagnetic radiation to the sample, a receiver that receives the electromagnetic radiation reflected by the sample or transmitted through the sample, and a data acquisition device. The comparative example system determines the adhesive strength between the first layer and the second layer based on the waveform of the electromagnetic radiation reflected from the sample or transmitted through the sample.

[0020] However, the system in the comparative example emits electromagnetic radiation from an external source onto a stationary sample and determines the adhesive strength based on the waveform of the reflected electromagnetic radiation, making it difficult to accurately distinguish between cases where the first and second layers are weakly bonded and cases where they are strongly bonded. Therefore, the system in the comparative example had difficulty measuring the adhesive strength between layers of a sample with high accuracy. Accordingly, this disclosure describes a measuring device and a measuring method that can measure the adhesive strength between layers with high accuracy.

[0021] <Embodiment> (First Embodiment) Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In each drawing, parts having the same configuration or function are denoted by the same reference numerals. In the description of this embodiment, redundant descriptions of the same parts may be omitted or simplified as appropriate.

[0022] The measuring device according to this embodiment irradiates a sample, which is a sample to be measured consisting of multiple layers, with electromagnetic waves while vibrating the sample. The measuring device detects the frequency, amplitude, etc., of the vibration at the interface at the measurement point from the reflected waves and measures the adhesive strength at the interface of the adherend. In this way, the measuring device according to this embodiment measures the adhesive strength according to the vibration characteristics of the measurement point detected from the reflected waves from the vibrating sample, making it possible to measure the adhesive strength between layers with high accuracy.

[0023] Figure 1 is a diagram showing the schematic configuration of a measurement system 100 including a measuring device 20 according to one embodiment. The measurement system 100 comprises the measuring device 20 and a terminal device 16. The measurement system 100 measures the inter-layer adhesive strength in a sample 30 consisting of multiple plate-shaped layers. In the example of Figure 1, the sample 30 comprises a third layer (a substrate 33), a second layer (an adhesive 32), and a first layer (a substrate 31), which are stacked sequentially from the bottom to the top of the paper. The substrates 31 and 33 are plate-shaped resins that are bonded to each other by the adhesive 32 provided between them. The substrates 31 and 33 may be made of, for example, polypropylene or polyethylene. The material of the adhesive 32 can be anything that bonds the substrates 31 and 33, for example, a water-based adhesive, a solvent-based adhesive, a chemical reaction-based adhesive, or a hot-melt adhesive. The following describes an example where the surfaces of the adherends 31, 33 and the adhesive 32 all have a planar shape with horizontal extension, and the adherends 33, adhesive 32, and adherend 31 are stacked sequentially from vertically downward to vertically upward. However, the shape and arrangement of the sample 30 are not limited to this. For example, the surfaces of the adherends 31, 33, and adhesive 32 may have a curved shape. Also, at least one of the surfaces of the adherends 31, 33, and adhesive 32 may be arranged to have a certain inclination with respect to the horizontal plane. The sample 30 may be, for example, the casing of an aircraft or the wall surface of a building.

[0024] The measuring device 20 comprises a measuring device body 12 and a transducer 15. In the example shown in Figure 1, the measuring device body 12 and the transducer 15 are placed on the surface of the adherend 31. The measuring device body 12 is positioned vertically above the measurement target portion 35 within the sample 30, and irradiates the sample 30 with electromagnetic waves. The reflected waves from the sample 30 are analyzed to measure the adhesive strength in the measurement target portion 35. The measurement target portion 35 is located within the adhesive 32 between adherends 31 and 33.

[0025] The transducer 15 is a device that applies vibration to the sample 30 when the measuring device body 12 transmits and receives electromagnetic waves. The transducer 15 may apply vibration to the sample 30 by outputting sound waves, including ultrasound, for example. Specifically, for example, the transducer 15 may output sound waves using a phased array or by using laser ablation of the material to vibrate the sample 30. Figure 1 shows an example in which vibration is applied to the sample 30 by contacting the adherend 31, which is the laser irradiation surface, but the transducer 15 may apply vibration to the sample 30 from any location. For example, the transducer 15 may apply vibration to the sample 30 from the adherend 33 located on the opposite side of the irradiation surface, or from the side of the sample 30. Alternatively, the transducer 15 may use a phased array or the like to scan the position where the measurement target part 35 is located in the depth direction to vibrate only a specific part. Furthermore, while Figure 1 shows a single oscillator 15 applying vibration to the sample 30, multiple oscillators 15 may also apply vibration to the sample 30.

[0026] The measuring device body 12 comprises a movable part 1(1a,1b), an optical unit 10, an electrical and electronic unit 11, a control unit 13, and a data processing unit 14. The movable part 1(1a,1b) includes any movable structure that can improve the portability of the measuring device body 12. For example, the movable part 1(1a,1b) may include tires attached to the measuring device body 12. The measuring device body 12 is movable on the surface of the object to be attached 31 by the tires or the like that which constitute the movable part 1(1a,1b). The movable part 1(1a,1b) allows the measuring device body 12 to move so that the irradiation position of electromagnetic waves on the sample 30 can be scanned.

[0027] The optical unit 10 irradiates the sample 30 with electromagnetic waves, receives the reflected waves from the sample 30, and outputs the reflected waves as electrical signals to the electrical and electronic unit 11. As an example, the optical unit 10 is described below in which an optical system is provided for measuring the frequency and amplitude of vibrations in the part to be measured 35 by optical Doppler measurement, but the method for measuring the frequency and amplitude of vibrations is not limited to this. For example, if the amplitude of vibrations in the part to be measured 35 is greater than a predetermined value, or if the frequency of vibrations is greater than a predetermined value, the measuring device 20 may simply measure the frequency and amplitude of vibrations from the phase displacement of the reflected waves. The optical unit 10 includes a lens 2, a mirror 3, a beam splitter 4 (4a, 4b, 4c), an acousto-optics modulator (hereinafter referred to as "AOM") 5, an optical signal / electrical signal converter 6, and a laser light source 7.

[0028] In the optical unit 10, the laser light source 7, which serves as an electromagnetic wave output source, outputs a laser as an electromagnetic wave. The laser light source 7 may be composed of a light-emitting device capable of outputting a laser in a frequency band closer to the frequency band that has high penetration into the resin constituting the adherend 31. The laser band may be, for example, around 0.1 THz to 10 THz, or it may be a microwave, millimeter wave, or terahertz wave. Hereinafter, the frequency of the laser output by the laser light source 7 will be denoted as f. The laser signal wave output by the laser light source 7 acts as a carrier wave to transmit information indicating the vibration of the measurement target part 35 by the oscillator 15.

[0029] The laser output from the laser light source 7 is split into two by the beam splitter 4b. Of the two lasers split by the beam splitter 4b, one is directed to the AOM 5, and the other is directed to the beam splitter 4a. The beam splitters 4 (4a, 4b, 4c) may be, for example, half mirrors.

[0030] The AOM5 takes the frequency f of the laser input via the beam splitter 4b and converts it to frequency f + f off Displace to the offset frequency f. off is the frequency f+f off The laser frequency is selected from a range of values ​​such that it penetrates the resin constituting the adherend 31. The laser, whose frequency has been shifted in AOM5, is then led to the beam splitter 4c.

[0031] The laser input from AOM5 to beam splitter 4c passes through beam splitter 4c, its focal position is adjusted by lens 2, and it is incident on the adherend 31. The laser incident on adherend 31 passes through adherend 31 and is reflected at the measurement target portion 35 within the adhesive 32. Since the sample 30 is vibrated by oscillator 15, the reflected wave is f+f, which reflects the vibration of the measurement target portion 35. off ±f d It contains the frequency components of f. d This represents the change in the frequency of the laser displaced by the vibration of the measurement target part 35, and is equal to the vibration frequency of the measurement target part 35. The reflected wave reflected from the measurement target part 35 has its focal position adjusted by lens 2 and is incident on beam splitter 4c. In the example of Figure 1, lens 2 adjusts the focal positions of both the laser as the incident wave irradiated onto the sample 30 and the reflected wave from the sample 30, but separate lenses may be provided for the incident wave and the reflected wave.

[0032] The reflected wave incident on beam splitter 4c is reflected by beam splitter 4c and guided to mirror 3. Mirror 3 reflects the input reflected wave and guides it to beam splitter 4a. f+f guided to beam splitter 4a off ±f d The reflected wave containing the frequency component passes through the beam splitter 4a and is guided to the O / E converter 6. On the other hand, the laser of frequency f guided from beam splitter 4b to beam splitter 4a is reflected at beam splitter 4a and is guided to the O / E converter 6.

[0033] The O / E converter 6 photoelectrically converts the input optical signal and outputs a current signal. Since the polarity of the laser output from the laser light source 7 is inverted when reflected by the measurement target portion 35, in the O / E converter 6, f + f off ±f d The component of frequency f between the reflected wave containing the frequency components of and the laser of frequency f cancels out. Therefore, the O / E converter 6 outputs a current signal reflecting the frequency f off ±f d . Thus, in this embodiment, the optical unit 10 interferes the reflected light frequency-shifted by the vibration of the AOM 5 and the sample 30 with the laser as the reference light output from the laser light source 7, and detects the signal related to the vibration of the sample 30 by the heterodyne method. The detection of the signal related to the vibration of the sample 30 is not limited to such a heterodyne method. For example, instead of the AOM 5, the mirror 3 is vibrated at the frequency f off so that the reflected wave from the measurement target portion 35 contains frequency components changed by f off only. The O / E converter 6 outputs a current signal containing the frequency components of f off ±f d to the electric and electronic unit 11.

[0034] The electric and electronic unit 11 analyzes the current signal of frequency f off ±f d input from the O / E converter 6 of the optical unit 10, and calculates the frequency and amplitude of the vibration in the measurement target portion 35. The electric and electronic unit 11 includes an F / V (Frequency / Voltage) converter 8 and a frequency / amplitude calculator 9. The F / V converter 8 outputs a voltage signal corresponding to the frequency f off ±f d of the current signal input from the O / E converter 6 to the frequency / amplitude calculator 9. The frequency / amplitude calculator 9 calculates the frequency, amplitude, etc. of the vibration in the measurement target portion 35 from the voltage signal input from the F / V converter 8.

[0035] Specifically, the frequency and amplitude calculator 9 performs frequency modulation (FM) on the current i output from the O / E converter 6 to determine the frequency f of the current i. off Calculate +Δν and the known offset frequency f off By calculating the difference between the two, Δν can be measured. Here, if t is time, V0 is the amplitude of the velocity of the oscillating part 35 being measured, and λ is the wavelength of the light source, then Δν is given by Equation 1.

number

[0036] The measuring device 20 measures the frequency and amplitude of vibrations at multiple points on the surface of the object to be attached 31, specifically at the measurement target portion 35 directly below each point, and analyzes the measurement data. The data processing unit 14 of the measuring device body 12 is a calculation unit that performs calculations on this data.

[0037] The control unit 13 controls the operation of each component of the measuring device 20. For example, the control unit 13 may control the operation of laser irradiation by the laser light source 7, vibration of the transducer 15, and analysis of measurement data by the data processing unit 14. The measuring device 20 may allow the range in which the measuring device body 12 scans the adherend 31 in order to measure the frequency and amplitude of vibrations at multiple measurement target parts 35 corresponding to multiple points. If such a scanning range is specified, the control unit 13 may control the operation of the movable parts 1 (1a, 1b) to move the measuring device body 12 to each point where measurement is to be performed, and measure the frequency and amplitude of vibrations at the measurement target part 35 corresponding to each point from each point. The control unit 13 includes one or more processors. In one embodiment, the "processor" is a general-purpose processor or a dedicated processor specialized for a specific process, but is not limited to these. The functions of the measuring device 20 may be realized by executing a program that can be used to make the measurement system 100 according to this embodiment function on the processor included in the control unit 13.

[0038] The terminal device 16 is an information processing device that receives user instructions regarding the operation of the measuring device 20. The terminal device 16 may be implemented as a general-purpose device such as a PC (personal computer), tablet, or smartphone, or as a dedicated device. Upon receiving instructions from the user, the terminal device 16 issues a measurement execution command according to the content of the instructions and outputs it to the data processing unit 14 of the measuring device 20. The data processing unit 14 outputs the input measurement execution command to the control unit 13. The control unit 13 controls the operation of each component of the measuring device 20, including setting, starting, and stopping the laser light source 7 and the oscillator 15, in accordance with the measurement execution command.

[0039] Next, the operation of the measuring device 20 will be described in detail with reference to Figure 2. Figure 2 is a flowchart showing an example of the measurement procedure using the measuring device 20 shown in Figure 1. Figure 2 shows an example of an operation procedure for measuring adhesive strength by switching the vibration frequency of the vibrator 15 between several values ​​at each of several measurement points on the adherend 31 and detecting the vibration frequency and amplitude, etc., at the measurement target part 35 for each vibration frequency. For example, the measuring device 20 may measure the adhesive strength by detecting the vibration frequency and amplitude, etc., at the measurement target part 35 when vibrations of 10 kHz, 15 kHz, and 20 kHz are applied at each of several predetermined measurement points. The range of such vibration frequencies may be determined, for example, according to the difference between the elastic modulus of the material (e.g., adherends 31, 33) and the elastic modulus of the adhesive 32. The operation of the measuring device 20 described with reference to Figure 2 corresponds to one of the measurement methods according to this embodiment. The operation of each step in Figure 2 is performed based on the control of the control unit 13. A program for causing a computer to execute the measurement method according to this embodiment may include each of the steps shown in Figure 2.

[0040] In step S1, the control unit 13 controls the laser light source 7 to output a laser.

[0041] In step S2, the control unit 13 sets the frequency of the oscillator 15 to a preset initial value. For example, the control unit 13 may set the initial value of the frequency of the oscillator 15 to 10 kHz.

[0042] In step S3, the control unit 13 starts the vibration output from the vibrator 15 at the set vibration frequency.

[0043] In step S4, the control unit 13 measures the reflected wave from the sample 30 of the laser output from the laser light source 7, whose frequency has been shifted in AOM 5, and calculates the frequency and amplitude of the vibration in the measurement target part 35. For example, as described above, the control unit 13 may calculate the frequency and amplitude of the vibration in the measurement target part 35 by optical Doppler measurement.

[0044] In step S5, the control unit 13 transfers the calculated vibration frequency and amplitude data to the terminal device 16.

[0045] In step S6, the control unit 13 determines whether the sweep of the predetermined frequencies of the oscillator 15 has been completed at the measurement point. For example, the control unit 13 may determine that the sweep is complete when it has completed measurements based on vibrations at frequencies of 10kHz, 15kHz, and 20kHz at the measurement point. If the sweep is complete (YES in step S6), the control unit 13 proceeds to step S8; otherwise (NO in step S6), it proceeds to step S7.

[0046] In step S7, the control unit 13 updates the frequency of the oscillator 15 with vibration frequencies that have not yet been measured at that measurement point. After completing the process in step S7, the control unit 13 returns to step S3 and continues processing.

[0047] In step S8, the control unit 13 determines whether the overall measurement has been completed, that is, whether the measurement has been completed for each of the predetermined vibration frequencies at all of the predetermined measurement points. If the overall measurement has been completed (YES in step S8), the control unit 13 proceeds to step S10; otherwise (NO in step S8), it proceeds to step S9.

[0048] In step S9, the control unit 13 moves the measuring device body 12 to the next measurement point where measurement has not yet been performed. To move the measuring device body 12, the control unit 13 may operate the movable parts 1 (1a, 1b), or it may notify the user to move the measuring device body 12, for example, via the display or audio output of the terminal device 16. After completing the processing in step S9, the control unit 13 returns to step S2 and continues processing.

[0049] In step S10, the control unit 13 stops the operation of the laser light source 7 and the oscillator 15.

[0050] In step S11, the control unit 13 analyzes the data obtained from the processing in steps S1 to S9 and measures the adhesive strength at each measurement point. Generally, when vibration is applied to the sample 30, it is thought that there will be differences in characteristics such as the frequency or amplitude of the vibration between the measurement target portion 35 with high adhesive strength and the measurement target portion 35 with low adhesive strength. For example, if the adherends 31 and 33 are not adhered, it is expected that the vibration of the interface will be a nonlinear vibration different from the vibration of the vibrator 15, depending on whether it is closed or open. Therefore, the control unit 13 determines the adhesive strength of the measurement target portion 35 based on the characteristics such as the frequency or amplitude of the vibration of that portion 35. For example, if the value of the frequency or amplitude of the vibration of one measurement target portion 35 is significantly different from the value of the frequency or amplitude of the vibration of another measurement target portion 35, the control unit 13 can determine that the adhesive strength of that measurement target portion 35 is weak. Specifically, for example, the control unit 13 can acquire the average value and standard deviation σ of the vibration frequency or amplitude of the measurement target portion 35 corresponding to each measurement point, and determine that the adhesive strength of the measurement target portion 35 is weak if the value of the frequency or amplitude is more than a certain value (e.g., 2σ) away from the average value. In this case, the control unit 13 may mark the measurement target portion 35 where the value of the vibration frequency or amplitude is more than a certain value away from the average value for each frequency of the vibrator 15. Then, the control unit 13 can determine that the adhesive strength of the measurement target portion 35 that has been marked for at least one vibration frequency of the vibrator 15 is weak. Alternatively, the control unit 13 can determine that the adhesive strength of the measurement target portion 35 that has been marked for two or more or all vibration frequencies of the vibrator 15 is weak.

[0051] Furthermore, the measuring device 20 can determine that the adhesive strength of the part to be measured 35, which is vibrating with characteristics significantly different from those of the vibrator 15, is weak. For example, the measuring device 20 can determine that the adhesive strength of the part to be measured 35 is weak if the difference in frequency or amplitude between the vibration of the vibrator 15 and the part to be measured is greater than or equal to a certain value. The measuring device 20 may also acquire in advance the relationship between the characteristics of the vibration of the part to be measured 35, such as frequency or amplitude, and the adhesive strength for each type of sample 30, measurement environment (including the vibration frequency of the vibrator 15), etc., and store it in a memory device. In that case, the control unit 13 may compare the measured values ​​of the vibration frequency or amplitude of the part to be measured 35 with the information showing the relationship between characteristics and adhesive strength that has been stored in the memory device in advance, and determine the adhesive strength of the part to be measured 35. In this case as well, the measuring device 20 can further improve the accuracy of the adhesive strength determination by switching the vibration frequency of the vibrator 15 between multiple values ​​and detecting the vibration frequency and amplitude of the vibration of the part to be measured 35 for each vibration frequency. Furthermore, the measuring device 20 may determine the adhesive strength by using phase information in addition to, or instead of, the frequency and amplitude of the vibration of the part to be measured 35.

[0052] Thus, the control unit 13 may obtain a value indicating the adhesive strength in each measurement target portion 35, for example, by the difference between the vibration characteristics of that measurement target portion 35 and a reference vibration characteristic. Such a reference vibration characteristic may be, for example, the average value of the vibration characteristics of other measurement target portions 35, the vibration characteristics of the vibrator 15, or a value related to a previously learned characteristic. Furthermore, measurement target portions 35 in which the difference between the value indicating the adhesive strength and the reference vibration characteristic is a certain value (for example, 2σ) or more may be marked as having weak adhesive strength.

[0053] In step S12, the control unit 13 displays an image showing the measurement result (diagnosis result) on the display of the terminal device 16. For example, the control unit 13 may display values ​​indicating the adhesive strength at each measurement point, and the marked measurement target portion 35, etc. After completing the process in step S12, the control unit 13 terminates the flowchart process. Although Figure 2 shows an example where the vibration of the transducer 15 is started in step S3 after the laser output is started in step S1, the measuring device 20 may start the vibration of the transducer 15 before starting the laser output.

[0054] As described above, the measuring device 20 vibrates the sample 30 to be measured while irradiating it with a microwave, millimeter wave, or terahertz wave laser, causing the laser to penetrate the adherend 31, and performs Doppler measurement of the reflection from the measurement target portion 35 at the adhesive interface to be observed. This allows for highly accurate determination of the adhesive state at the measurement target portion 35. In other words, as in the comparative example, it is difficult to distinguish between a state where the layers constituting the sample 30 are in contact but not adhered in a static state. The measuring device 20 makes the difference between the state where they are in contact but not adhered and the state where they are adhered apparent by vibrating the sample 30. For example, if the layers constituting the sample 30 are in contact but not adhered, vibration will cause closing and opening. This results in complex vibration behavior, and the vibration spectrum of the measurement target portion 35 will contain various frequency components. The measuring device 20 utilizes this property to measure the adhesive strength at the measurement target portion 35 with high accuracy.

[0055] (Second Embodiment) As described above, when a laser is irradiated onto the sample 30 and the adhesive strength at the measurement target portion 35 is determined based on the reflected wave, the signal of interest is the reflected wave from the adhesive interface, and the reflected wave from the interface between the air and the adherend 31 is noise and should be removed as much as possible. Therefore, the measuring device 20 may incident P-polarized light onto the adherend 31 at a Brewster angle. Figure 3 is a schematic diagram showing how the laser output from the measuring device 20 in Figure 1 is reflected.

[0056] In Figure 3, the optical section 10 of the measuring device 20 irradiates a P-polarized laser from aperture 101a and receives the reflected wave at aperture 101b. The measuring device 20 may irradiate a P-polarized laser by, for example, providing a polarizing filter at aperture 101a. Aperture 101a is such that the irradiated laser is at a Brewster angle θ with respect to the surface of the adherend 31. B It is adjusted to form the Brewster angle θ. B This is determined based on the refractive index of the adherend 31.

[0057] Thus, the measuring device 20 uses a P-polarized laser at a Brewster angle θ B By irradiating the adherend 31 with this device, the reflected waves from the interface between the air and the adherend 31 can be reduced to zero. Therefore, the measuring device 20 can eliminate the reflected waves that cause noise and measure the adhesive strength of the measurement target portion 35 with high accuracy.

[0058] (Third embodiment) Furthermore, the intensity of the reflected wave may be increased by adding an additive to the adhesive or other material constituting the sample 30 to enhance the reflectivity of the laser. Figures 4A to 4C schematically show the relationship between the frequency of the laser output from the measuring device 20 in Figure 1 and the intensity of the reflected wave from the interface of the sample 30.

[0059] When the refractive indices of the adherend 31 and the adhesive 32 are close, sufficient reflection intensity may not be obtained at the adhesive interface between the adherend 31 and the adhesive 32. Therefore, in order to obtain a more intense reflected wave from the adhesive interface between the adherend 31 and the adhesive 32, as shown in Figure 4A, an additive with high reflection intensity may be added to the adhesive 32 with respect to the frequency f1 used for the irradiating laser. This increases the intensity of the reflected wave from the adhesive interface between the adherend 31 and the adhesive 32, and the measuring device 20 can measure the adhesive strength with high accuracy. Note that in Figures 4A to 4C, the offset frequency f offThe notation has been omitted. Similarly, in order to obtain high reflectivity from the adhesive interface between the adhesive 32 and the adherend 33, an additive with high reflectivity may be applied to the adherend 33 for the frequency f2 used in the laser irradiation, as shown in Figure 4B. Metamaterials may be used as such additives that exhibit high reflectivity at specific frequencies f1 and f2.

[0060] Furthermore, the measuring device 20 may use a laser with frequency f3, which has a high reflectivity to air, to detect vibrations of air interfaces (voids 37) that are specific foreign matter present in the adhesive 32. In addition, the measuring device 20 may be equipped with multiple laser light sources 7 capable of outputting lasers of frequencies f1, f2, and f3, and the reflected waves from each frequency laser can be measured by switching between the laser light sources 7. This makes it possible to select a specific type of interface inside the sample 30 as the measurement target portion 35 and measure its adhesive strength.

[0061] Furthermore, the transducer 15 may use an ultrasonic phased array to apply a vibration load precisely to the area to be vibrated. This minimizes the influence of vibrations occurring in areas other than the measurement target area 35. Therefore, the measuring device 20 can measure the adhesive strength of a specific measurement target area 35 with even greater precision.

[0062] As described above, when the complex refractive indices of the adherend 31 and the adhesive 32 are close and the interfacial reflection intensity of the measurement target portion 35 is low, an additive designed to obtain a large reflection at the frequency of the irradiated laser may be added to the adhesive 32. This increases the intensity of the reflected wave obtained from the surface of the adhesive 32, enabling the measuring device 20 to perform highly accurate measurements. Furthermore, the measuring device 20 may be equipped with multiple types of laser light sources 7 for irradiating the laser, and the control unit 13 may switch between using these laser light sources 7. This allows the measuring device 20 to measure, for example, the adhesive strength at the interface between the adherend 31 and the adhesive 32, the adhesive strength at the interface between the adhesive 32 and the adherend 33, and the presence or absence of voids 37.

[0063] Furthermore, although the above embodiments described examples where the sample 30 to be measured has a three-layer structure consisting of an adherend 31, an adhesive 32, and an adherend 33, the sample 30 to be measured is not limited to such a three-layer structure as long as it has multiple layers. For example, the sample 30 may have a two-layer structure in which two resins (e.g., adherends 31 and 33) are mechanically joined together. The measuring device 20 may, using the method of each embodiment above, measure a sample 30 in which a resin such as NMT (registered trademark) and a metal are anchor-bonded at the nano level, and measure the adhesive strength of the anchor joint.

[0064] As described above, the control unit 13 of the measuring device 20 outputs electromagnetic waves from the laser light source 7 to a sample 30 having adjacent first layers (e.g., adherend 31) and second layers (e.g., adhesive 32) that are vibrated at a predetermined vibration frequency by the vibrator 15. The control unit 13 receives reflected electromagnetic waves from the measurement target portion 35 at the interface between the first layer and the second layer, and calculates the vibration frequency or amplitude of the measurement target portion 35 based on the reflected waves. The control unit 13 measures the adhesive strength of the measurement target portion 35 based on the vibration frequency or amplitude of the measurement target portion 35 calculated based on the reflected waves. In this way, the measuring device 20 can measure the adhesive strength between layers with high accuracy because it acquires the vibration frequency or amplitude of the measurement target portion 35 when the strength of the adhesive strength at the interface is revealed by vibration and measures the adhesive strength.

[0065] Furthermore, the control unit 13 may measure the adhesive strength of the part to be measured 35 based on the frequency spectrum of the vibration of the part to be measured 35 in a frequency band that includes frequencies different from the vibration frequency. If the adhesive strength at the interface of multiple layers is insufficient, the part to be measured 35 will vibrate irregularly and nonlinearly due to differences in the elastic modulus between the layers, etc. As a result, the frequency spectrum of the vibration of the part to be measured 35 will be wider than the frequency of the vibrator 15. Therefore, the control unit 13 can measure the adhesive strength of the part to be measured 35 with even greater accuracy by referring to the frequency spectrum of the vibration of the part to be measured 35 in a frequency band that includes frequencies different from the vibration frequency of the vibrator 15.

[0066] Furthermore, the control unit 13 may calculate the frequency or amplitude of the vibration of the part to be measured 35 based on the reflected wave, based on the Doppler measurement. In this case, the influence of background noise can be reduced, and the measuring device 20 can measure the adhesive strength of the part to be measured 35 with even greater precision.

[0067] Furthermore, the control unit 13 may output a P-polarized laser from the laser light source 7 to the sample 30 at a Brewster angle as an electromagnetic wave. This eliminates the influence of reflected waves from the surface of the sample 30, allowing the measuring device 20 to measure the adhesive strength of the measurement target portion 35 with even greater precision.

[0068] Furthermore, the control unit 13 may output electromagnetic waves to a sample 30 that has been vibrated at a first vibration frequency, which is a predetermined vibration frequency. The control unit 13 may calculate a first frequency or a first amplitude, which is the vibration frequency or amplitude of the measurement target portion 35, based on the reflected electromagnetic waves from the measurement target portion 35 of the sample 30 that has been vibrated at the first vibration frequency. In addition, the control unit 13 may output electromagnetic waves to a sample 30 that has been vibrated at a second vibration frequency, which is a predetermined vibration frequency. The control unit 13 may calculate a second frequency or a second amplitude, which is the vibration frequency or amplitude of the measurement target portion 35, based on the reflected electromagnetic waves from the measurement target portion 35 of the sample 30 that has been vibrated at the second vibration frequency. Then, the control unit 13 may measure the adhesive strength of the measurement target portion 35 based on at least one of the first frequency and the second frequency, and the first amplitude and the second amplitude. Thus, the measuring device 20 may utilize both the frequency or amplitude of the reflected wave from the sample 30 when vibration of the first vibration frequency is applied, and the frequency or amplitude of the reflected wave from the sample 30 when vibration of the second vibration frequency is applied. Therefore, the measuring device 20 can measure the adhesive strength of the part to be measured 35 with even greater precision.

[0069] Furthermore, the control unit 13 may output electromagnetic waves toward each of the multiple measurement target portions 35 at the interface between the first layer and the second layer, and receive reflected electromagnetic waves from each of the multiple measurement target portions 35. The control unit 13 may analyze the reflected waves from each of the multiple measurement target portions 35 and calculate the frequency or amplitude of the vibration of the measurement target portion 35. The control unit 13 may measure the adhesive strength of each of the multiple measurement target portions 35 based on a comparison between the frequency or amplitude of the vibration of the measurement target portion 35 and the average value of the vibration frequencies or amplitudes of the multiple measurement target portions 35. In this way, the measuring device 20 can further improve the measurement accuracy by measuring the frequency or amplitude of the vibration of multiple measurement target portions 35 and measuring the adhesive strength of a particular measurement target portion 35 based on a comparison with the average value of the vibration frequencies or amplitudes of the multiple measurement target portions 35.

[0070] Furthermore, the control unit 13 may output electromagnetic waves of the first frequency f1 from the first electromagnetic wave output source (laser light source 7) to the sample 30 to which an additive that increases the reflectivity of electromagnetic waves of the first frequency f1 has been applied to the second layer. As a result, the measuring device 20 can receive reflected waves with high reflection intensity from the second layer, and can measure the adhesive strength of the measurement target portion 35 located at the interface between the first layer and the second layer with even greater precision.

[0071] Furthermore, the control unit 13 may output electromagnetic waves of the second frequency f2 from a second electromagnetic wave output source to a sample 30 further having a third layer (e.g., an adherend 33) adjacent to the second layer, to which an additive is added to increase the reflectivity of electromagnetic waves of the second frequency f2. The control unit 13 may receive reflected waves of electromagnetic waves of the second frequency f2 from the measurement target portion 35 at the interface between the second and third layers. Based on the reflected waves of the second frequency f2, the control unit 13 may calculate the frequency or amplitude of vibration of the measurement target portion 35 at the interface between the second and third layers. Based on the frequency or amplitude of vibration of the measurement target portion 35 at the interface between the second and third layers, the control unit 13 may measure the adhesive strength of the measurement target portion 35 at the interface between the second and third layers. Thus, the measuring device 20 may irradiate a sample 30 having a third layer to which an additive that increases the reflectivity of electromagnetic waves of the second frequency f2 is applied with electromagnetic waves of the second frequency f2. Then, the measuring device 20 may measure the adhesive strength of the portion to be measured 35 at the interface between the second layer and the third layer based on the reflected waves. As a result, the measuring device 20 can receive reflected waves with high reflectivity from the third layer, and can measure the adhesive strength of the portion to be measured 35 at the interface between the second layer and the third layer with high accuracy.

[0072] Furthermore, the control unit 13 may output an electromagnetic wave of a third frequency f3 from the third electromagnetic wave output source that reflects off a specific foreign object (for example, an air gap 37), and determine whether a specific foreign object is present in the sample 30 based on the reception of the reflected electromagnetic wave of the third frequency f3 from the sample 30. Thus, the measuring device 20 can determine whether or not a foreign object is present in the sample 30.

[0073] This disclosure is not limited to the embodiments described above. For example, multiple blocks shown in the block diagram may be combined, or one block may be divided. Multiple steps shown in the flowchart may be performed in parallel or in a different order, depending on the processing capacity of the device performing each step, or as necessary, instead of being performed in chronological order as described. Other modifications are possible without departing from the spirit of this disclosure. [Explanation of symbols]

[0074] 1a,1b Moving parts 2 lenses 3 Mirror 4a, 4b, 4c Beam Splitter 5 AOM 6 O / E Converters 7. Laser light source 8 F / V Converter 9. Frequency and Amplitude Calculator 10 Optics Department 11 Electrical and Electronic Engineering Department 12 Measuring device main body 13 Control Unit 14 Data Processing Unit 15. Oscillator 16 devices 20 Measuring devices 30 samples 31,33 Adherent 32 Adhesives 35. Part to be measured 37 void 100 Measurement Systems 101a,101b opening

Claims

1. For a sample having adjacent first and second layers to which vibration is applied at a predetermined vibration frequency, an electromagnetic wave having a frequency that penetrates the first layer is output from an electromagnetic wave output source. The reflected electromagnetic waves from the portion to be measured at the interface between the first layer and the second layer are received. Based on the reflected wave, the frequency or amplitude of the vibration of the part to be measured is calculated. Based on the frequency or amplitude of the vibration of the part to be measured calculated based on the reflected wave, the adhesive strength of the part to be measured is measured. A measuring device equipped with a control unit.

2. The measuring apparatus according to claim 1, wherein the control unit measures the adhesive strength of the part to be measured based on the frequency spectrum of the vibration of the part to be measured in a frequency band that includes a frequency different from the vibration frequency.

3. The measuring apparatus according to claim 1, wherein the control unit calculates the frequency or amplitude of the vibration of the part to be measured based on the reflected wave, based on Doppler measurement.

4. The measuring apparatus according to claim 1, wherein the control unit outputs a P-polarized laser from a laser light source to the sample at a Brewster angle as the electromagnetic wave.

5. The control unit, The electromagnetic wave is output to the sample to which vibration is applied at a first vibration frequency, which is a predetermined vibration frequency, and the first frequency or first amplitude, which is the vibration frequency or amplitude of the measurement target portion, is calculated based on the reflected wave of the electromagnetic wave from the measurement target portion of the sample to which vibration is applied at the first vibration frequency. The electromagnetic wave is output to the sample to which vibration is applied at a second vibration frequency, which is a predetermined vibration frequency, and the second frequency or second amplitude, which is the vibration frequency or amplitude of the measurement target portion, is calculated based on the reflected wave of the electromagnetic wave from the measurement target portion of the sample to which vibration is applied at the second vibration frequency. The adhesive strength of the part to be measured is measured based on at least one of the first frequency and the second frequency, and the first amplitude and the second amplitude. The measuring device according to claim 1.

6. The control unit, Electromagnetic waves are output towards each of the multiple measurement target portions at the interface between the first layer and the second layer. The reflected electromagnetic waves from each of the multiple measurement target parts are received. For each of the aforementioned multiple measurement target parts, the reflected wave from the measurement target part is analyzed to calculate the frequency or amplitude of the vibration of the measurement target part. For each of the multiple measurement target parts, the adhesive strength of the measurement target part is measured based on a comparison between the vibration frequency or amplitude of the measurement target part and the average value of the vibration frequencies or amplitudes of the multiple measurement target parts. The measuring device according to claim 1.

7. The measuring apparatus according to claim 1, wherein the control unit outputs electromagnetic waves of the first frequency from the first electromagnetic wave output source to the sample in which an additive that increases the reflectivity of electromagnetic waves of the first frequency is applied to the second layer.

8. The control unit, The sample further comprises a third layer adjacent to the second layer, to which an additive is applied to increase the reflectivity of electromagnetic waves of a second frequency, and electromagnetic waves of the second frequency are output from the second electromagnetic wave output source. The reflected electromagnetic wave of the second frequency from the portion to be measured at the interface between the second layer and the third layer is received. Based on the reflected wave of the second frequency, the frequency or amplitude of the vibration of the measured portion at the interface between the second layer and the third layer is calculated. The adhesive strength of the portion to be measured at the interface between the second layer and the third layer is measured based on the frequency or amplitude of the vibration of the portion to be measured at the interface between the second layer and the third layer. The measuring device according to claim 1.

9. The control unit, From the third electromagnetic wave output source, an electromagnetic wave of a third frequency that is reflected by a specific foreign object is output. In response to receiving reflected electromagnetic waves of the third frequency from the sample, it is determined that the specific foreign substance is present in the sample. The measuring device according to claim 1.

10. A measurement method for a measuring device, The control unit, A step of outputting electromagnetic waves having a frequency that penetrates the first layer from an electromagnetic wave output source to a sample having a first layer and a second layer adjacent to each other that are subjected to vibration at a predetermined vibration frequency, A step of receiving the reflected electromagnetic wave from the portion to be measured at the interface between the first layer and the second layer, A step of calculating the frequency or amplitude of the vibration of the part to be measured based on the reflected wave, A step of measuring the adhesive strength of the part to be measured based on the frequency or amplitude of the vibration of the part to be measured calculated based on the reflected wave, Measurement methods, including those mentioned above.

Images