Evaluation device and evaluation method

Abstract

To provide an evaluation device and an evaluation method with which it is possible to efficiently evaluate the hardening state of an adhesive in a resin structure.SOLUTION: An evaluation device 1 evaluates the hardening state of an adhesive AD in a resin structure RS obtained by bonding a plurality of resin bodies R1, R2 together by the adhesive AD. The evaluation device 1 comprises: light sources 21, 22 for irradiating a region AR of the resin structure including the adhesive AD with near-infrared rays N1, N2; an image sensor 3 for receiving light L obtained from the region AR by being irradiated with near-infrared rays N1, N2 and converting the received light into a plurality of pixel values; and a control device 4 for performing processing to evaluate the hardening state by using the plurality of pixel values.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an evaluation device and an evaluation method. [Background technology]

[0002] There is a known method of monitoring the curing process of an adhesive by near-infrared spectroscopy (see, for example, Non-Patent Documents 1 and 2). Non-Patent Documents 1 and 2 report that the curing process of an adhesive can be monitored non-destructively and non-contactly by analyzing the spectrum of near-infrared light and tracking changes in the peak value. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Yasuto Fujimaki, Miyuki Furusugi, Jun Inoue, “Monitoring the adhesive curing process by near-infrared spectroscopy”, The 102nd Annual Meeting of the Chemical Society of Japan, March 23, 2022 [Non-Patent Document 2] Yasuto Fujimaki, Miyuki Furusugi, Jun Inoue, “Monitoring adhesive curing inside resin structures by near-infrared spectroscopy”, 71st Annual Meeting of the Japan Society for Analytical Chemistry, September 15, 2022 Summary of the Invention [Problem to be solved by the invention]

[0004] In the monitoring methods described in Non-Patent Documents 1 and 2, it is necessary to analyze the spectrum of near-infrared light and track changes in the peak value, which takes time to evaluate the curing state of the adhesive.

[0005] The present disclosure describes an evaluation device and an evaluation method that can efficiently evaluate the cured state of an adhesive in a resin structure. [Means for solving the problem]

[0006] An evaluation device according to one aspect of the present disclosure is a device for evaluating a cured state of an adhesive in a resin structure obtained by bonding a plurality of resin bodies with the adhesive. The evaluation device includes a light source that irradiates a region of the resin structure containing the adhesive with near-infrared light, a conversion unit that receives light obtained by irradiating the region with the near-infrared light and converts the light into a plurality of pixel values, and a control unit that performs processing for evaluating the cured state using the plurality of pixel values.

[0007] An evaluation method according to another aspect of the present disclosure is a method for evaluating a cured state of an adhesive in a resin structure obtained by bonding a plurality of resin bodies with the adhesive, the evaluation method including the steps of irradiating a region of the resin structure containing the adhesive with near-infrared light, receiving light obtained by irradiating the region with the near-infrared light and converting the light into a plurality of pixel values, and performing processing for evaluating the cured state using the plurality of pixel values.

[0008] In this evaluation device and evaluation method, near-infrared light is irradiated onto an area of ​​a resin structure that contains an adhesive, and the light obtained by irradiating the area with near-infrared light is converted into a plurality of pixel values ​​and processed for evaluation of the cured state. In general, the adhesive shrinks during the curing process, and the volume of the adhesive decreases. At this time, cracks may occur on the surface of the adhesive. Therefore, the more cracks there are, the more the adhesive has cured. The near-infrared light passes through the part of the adhesive that does not have cracks and is scattered in the part where the cracks have occurred. Therefore, when the area is irradiated with near-infrared light from the same side as the conversion unit, the pixel value of the part where the cracks have occurred increases, and when the area is irradiated with near-infrared light from the opposite side to the conversion unit, the pixel value of the part where the cracks have occurred decreases. In this way, the occurrence of cracks is reflected in the pixel value, so it is possible to evaluate the cured state of the adhesive based on the plurality of pixel values ​​without analyzing the spectrum of the near-infrared light. From the above, it is possible to efficiently evaluate the cured state of the adhesive in the resin structure.

[0009] In some embodiments, the evaluation device may further include a display unit that displays an image corresponding to a plurality of pixel values. The control unit may cause the image to be displayed on the display unit. In this configuration, a user of the evaluation device can recognize the entire area including the adhesive from the image. Therefore, the user can evaluate the cured state of the adhesive simply by visually checking the image. Therefore, it becomes possible to easily evaluate the cured state of the adhesive.

[0010] In some embodiments, the control unit may evaluate the curing state based on the plurality of pixel values. In this configuration, since the control unit evaluates the curing state, it is possible to objectively evaluate the curing state of the adhesive.

[0011] In some embodiments, the control unit may binarize each of the plurality of pixel values ​​and evaluate the curing state based on the number of pixel values ​​having any one of the values. According to this configuration, the curing state is quantitatively evaluated since the evaluation is based on the number of pixel values ​​having any one of the values ​​among the binarized pixel values.

[0012] In some embodiments, the light source may irradiate the region with near-infrared light from the same side as the conversion unit, and the conversion unit may receive the light scattered in the region. As described above, the near-infrared light passes through the portion of the adhesive where no cracks have occurred and is scattered in the portion where a crack has occurred. Therefore, according to the above configuration, the scattered light generated in the portion where a crack has occurred can be received, so that the pixel value of the portion becomes large. In this way, the occurrence of a crack is reflected in the pixel value, so that it is possible to evaluate the curing state of the adhesive based on multiple pixel values ​​without analyzing the spectrum of the near-infrared light.

[0013] In some embodiments, the light source may irradiate the region with near-infrared light from the side opposite to the conversion unit, and the conversion unit may receive the transmitted light that has passed through the region as the light. As described above, the near-infrared light passes through the portion of the adhesive where no cracks have occurred, and is scattered in the portion where the cracks have occurred. Therefore, according to the above configuration, the transmitted light that has passed through the portion other than the portion where the cracks have occurred can be received, so that the pixel value of the portion where the cracks have occurred becomes smaller. In this way, the occurrence of the cracks is reflected in the pixel value, so that it is possible to evaluate the curing state of the adhesive based on multiple pixel values ​​without analyzing the spectrum of the near-infrared light. Effect of the Invention

[0014] According to the present disclosure, it is possible to efficiently evaluate the cured state of an adhesive in a resin structure. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic diagram of an evaluation device according to an embodiment. [Diagram 2] FIG. 2 is a side view that diagrammatically illustrates the resin structure shown in FIG. [Diagram 3] FIG. 3 is a flowchart showing an example of an evaluation method in the evaluation device shown in FIG. [Figure 4] FIG. 4 is a diagram showing the change over time in the cured state of the adhesive observed based on scattered light. [Diagram 5] FIG. 5 is a diagram showing the change over time in the cured state of the adhesive observed based on transmitted light. [Figure 6] FIG. 6 is a diagram for explaining the evaluation by the control device shown in FIG. [Figure 7] FIG. 7 is a diagram showing the change over time in the number of black pixels in a binarized image. [Figure 8] FIG. 8 is a diagram showing the change over time of the peak intensity ratio measured by near-infrared spectroscopy. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the description of the drawings, the same elements are given the same reference numerals, and duplicated description will be omitted.

[0017] An evaluation device according to one embodiment will be described with reference to FIG. 1. FIG. 1 is a schematic diagram of the evaluation device according to one embodiment. The evaluation device 1 shown in FIG. 1 is a device that evaluates the cured state of an adhesive AD in a resin structure RS. The resin structure RS is an object to be evaluated by the evaluation device 1, and is obtained by bonding a resin body R1 and a resin body R2 with the adhesive AD. The resin structure RS has an area AR that includes the adhesive AD. Details of the resin structure RS will be described later.

[0018] The evaluation device 1 includes a light source 21, a light source 22, an image sensor 3 (conversion unit), a control device 4 (control unit), a display 5 (display unit), and a sample stage SS. A resin structure RS is placed on the sample stage SS. The sample stage SS is made of a material that is transmissive to near-infrared light.

[0019] The light source 21 and the light source 22 irradiate the region AR of the resin structure RS with near-infrared light N1 and near-infrared light N2, respectively. Near-infrared light refers to light having a wavelength in the near-infrared region, which belongs to a wavelength range between red visible light and infrared light. The wavelength range of the near-infrared light N1 and N2 is, for example, 800 nm to 2500 nm. Examples of the light sources 21 and 22 include a halogen light source, a near-infrared LED (Light Emitting Diode), and a near-infrared laser diode. For example, either the light source 21 or the light source 22 is selected by a user of the evaluation device 1, and the selected light source is used to evaluate the cured state of the adhesive AD.

[0020] The light source 21 irradiates the region AR with near-infrared light N1 from the same side of the resin structure RS as the image sensor 3. Specifically, the light source 21 is provided above the sample stage SS, and irradiates the region AR with near-infrared light N1 from diagonally above the region AR. When the light source 21 receives an irradiation command from the control device 4, it irradiates the region AR with near-infrared light N1. The light source 22 irradiates the region AR with near-infrared light N2 from the opposite side of the resin structure RS to the image sensor 3. Specifically, the light source 22 is provided below the sample stage SS, and irradiates the region AR with near-infrared light N2 from directly below the region AR via the sample stage SS. When the light source 22 receives an irradiation command from the control device 4, it irradiates the region AR with near-infrared light N2.

[0021] The image sensor 3 is a near-infrared camera capable of detecting wavelengths in the near-infrared region. When the image sensor 3 receives an image capturing command from the control device 4, it captures an image of the area AR. Specifically, the image sensor 3 receives light L obtained by irradiating the area AR with near-infrared light N1 or near-infrared light N2, and converts the light L into a plurality of pixel values. The image sensor 3 is provided above the sample stage SS. More specifically, the image sensor 3 is provided directly above the resin structure RS arranged on the sample stage SS. The lens of the image sensor 3 faces downward.

[0022] When the light source 21 is used, the light L is scattered light obtained by scattering the near-infrared light N1 in the region AR. When the light source 22 is used, the light L is transmitted light obtained by transmitting the near-infrared light N2 through the region AR. The image sensor 3 includes, for example, a photodiode that converts the light L into a plurality of pixel values. The image sensor 3 transmits (outputs) the converted plurality of pixel values ​​to the control device 4.

[0023] The control device 4 is a device (controller) that controls the evaluation device 1 (light source 21, light source 22, image sensor 3, and display 5). The control device 4 may be configured as a computer system including a processor such as a CPU (Central Processing Unit), memories such as a RAM (Random Access Memory) and a ROM (Read Only Memory), input devices such as a touch panel, a mouse, and a keyboard, and a communication device such as a network card. The functions of the control device 4 may be realized by operating each piece of hardware under the control of the processor based on a computer program (application) stored in the memory.

[0024] The control device 4 transmits an irradiation command to the light source 21 or the light source 22, thereby causing the light source 21 or the light source 22 to irradiate near-infrared light. The control device 4 transmits an image capture command to the image sensor 3, thereby causing the image sensor 3 to capture an image and acquire a plurality of pixel values ​​from the image sensor 3. The control device 4 performs processing for evaluating the cured state of the adhesive AD using the plurality of pixel values. Specifically, the control device 4 transmits data including the plurality of pixel values ​​together with a display command to the display 5, thereby causing an image corresponding to the plurality of pixel values ​​to be displayed on the display 5.

[0025] The display 5 displays an image corresponding to the multiple pixel values. The display 5 acquires data including the multiple pixel values ​​from the control device 4, and displays an image corresponding to the multiple pixel values. The user of the evaluation device 1 checks the image displayed on the display 5 and evaluates the cured state of the adhesive AD.

[0026] Next, the resin structure RS will be described in detail with reference to FIG. 2. FIG. 2 is a side view that diagrammatically illustrates the resin structure illustrated in FIG. 1. The resin structure RS includes a resin body R1, a resin body R2, and an adhesive AD that bonds the resin body R1 and the resin body R2 to each other. In this embodiment, each of the resin body R1 and the resin body R2 is a resin plate. The main surface of the resin body R1 and the main surface of the resin body R2 are bonded via the adhesive AD. In other words, the resin body R1 and the resin body R2 are laminated with the adhesive AD sandwiched between them.

[0027] Each of the resin bodies R1 and R2 is made of a resin material that can transmit near-infrared light. Examples of materials that can be used for the resin bodies R1 and R2 include polyethylene resin, polypropylene resin, ABS (acrylonitrile butadiene styrene) resin, AS (acrylonitrile styrene) resin, PET (polyethylene terephthalate) resin, POM (polyoxymethylene) resin, phenol resin, polycarbonate resin, polyvinyl chloride resin, and acrylic resin. Examples of the adhesive AD that can be used include a cyanoacrylate adhesive, an epoxy adhesive, and an acrylic adhesive.

[0028] The length of the resin body R1 in the stacking direction (hereinafter referred to as "thickness D1") and the length of the resin body R2 in the stacking direction (hereinafter referred to as "thickness D2") are thicknesses that allow near-infrared light to pass through. Each of the thicknesses D1 and D2 is, for example, 5 mm or less. When each of the thicknesses D1 and D2 is about 1 mm, the resin bodies R1 and R2 transmit near-infrared light sufficiently, so that the evaluation device 1 can more reliably evaluate the cured state of the adhesive AD. The length of the adhesive AD in the stacking direction may be, for example, 0.5 mm to 1 mm.

[0029] Next, an evaluation method in the evaluation device 1 will be described with reference to Fig. 3. Fig. 3 is a flowchart showing an example of the evaluation method in the evaluation device shown in Fig. 1. When performing the evaluation, a user of the evaluation device 1 starts an evaluation application for evaluating the cured state of the adhesive AD in the control device 4, and places the resin structure RS to be evaluated on the sample stage SS. Then, the user selects a light source to be used for evaluation from light source 21 and light source 22 in the evaluation application, and performs an operation to start the evaluation, thereby starting a series of processes shown in Fig. 3.

[0030] First, the control device 4 transmits an irradiation command to the selected light source, causing the selected light source to irradiate near-infrared light. When the selected light source receives the irradiation command from the control device 4, it irradiates the area AR with near-infrared light (step S1). For example, when the light source 21 is selected, the light source 21 irradiates the area AR with near-infrared light N1 from diagonally above the area AR. When the light source 22 is selected, the light source 22 irradiates the area AR with near-infrared light N2 from directly below the area AR.

[0031] Next, the control device 4 transmits an image capturing command to the image sensor 3, causing the image sensor 3 to capture an image of the area AR. Upon receiving the image capturing command from the control device 4, the image sensor 3 receives light L obtained by irradiating the area AR with near-infrared light, and converts the light L into a plurality of pixel values ​​(step S2). The image sensor 3 then transmits the plurality of pixel values ​​to the control device 4. Note that step S2 may be performed in parallel with step S1.

[0032] Next, when the control device 4 receives the multiple pixel values ​​from the image sensor 3, it transmits a display command together with the multiple pixel values ​​to the display 5, causing the display 5 to display an image based on the multiple pixel values ​​(step S3). When the display 5 receives the multiple pixel values ​​and the display command from the control device 4, it displays an image corresponding to the multiple pixel values. Then, the user visually checks the image displayed on the display 5 and evaluates the cured state of the adhesive AD.

[0033] Next, examples of images displayed on the display 5 will be described with reference to Fig. 4 and Fig. 5. Fig. 4 is a diagram showing the change over time in the cured state of the adhesive observed based on scattered light. Fig. 5 is a diagram showing the change over time in the cured state of the adhesive observed based on transmitted light.

[0034] Each image shown in FIG. 4 is an image based on scattered light obtained by irradiating near-infrared light N1 from light source 21 onto region AR. POM resin (white), ABS resin (milky white), and phenolic resin (yellowish brown) were used as the constituent materials of resin body R1 and resin body R2, and a cyanoacrylate adhesive was used as adhesive AD. A halogen light source was used as light source 21. FIG. 4 shows images taken 0 hours, 1 hour, and 62 hours after bonding for each constituent material. Note that 62 hours after bonding, adhesive AD had completely hardened for all constituent materials.

[0035] As shown in FIG. 4, in the resin structure RS using any of the constituent materials, it can be seen that the image of the region including the adhesive AD becomes whiter over time. This is because the adhesive AD shrinks as it hardens, causing fine cracks in the adhesive AD and scattering the near-infrared light N1. To be more specific, as the adhesive AD hardens, the number of cracks increases. The near-infrared light N1 passes through the non-cracked parts of the adhesive AD and is scattered in the cracked parts, so that as the adhesive AD hardens, the intensity (amount of received light) of the light L received by the image sensor 3 increases. Therefore, as the adhesive AD hardens, the image of the region including the adhesive AD becomes whiter.

[0036] In view of the above, when the user selects light source 21 as the light source to be used for evaluation, the user may evaluate that the curing of the adhesive AD progresses as the image of the area including the adhesive AD becomes whiter.

[0037] Each image shown in FIG. 5 is an image based on transmitted light obtained by irradiating the region AR with near-infrared light N2 from the light source 22. A resin plate made of ABS resin having a thickness of 1 mm in the lamination direction was used as the resin body R1 and the resin body R2, and a cyanoacrylate adhesive was used as the adhesive AD. A halogen light source and a near-infrared LED light source were used as the light source 22. An LED light source emitting near-infrared light with a wavelength of 1300 nm was used as the near-infrared LED light source. The above wavelength is a wavelength that does not correspond to the absorption peak of either the ABS resin or the cyanoacrylate adhesive. By selecting a wavelength that does not correspond to the absorption peak of the resin as the wavelength of the near-infrared light, the transmittance of the near-infrared light to the resin can be ensured. By selecting a wavelength that does not correspond to the absorption peak of the adhesive as the wavelength of the near-infrared light, the curing state of the adhesive can be evaluated without being affected by the change in the absorption peak accompanying the curing of the adhesive. FIG. 5 shows images taken for each type of light source 0 minutes, 30 minutes, 60 minutes, 120 minutes, and 600 minutes after adhesion.

[0038] As shown in FIG. 5, it can be seen that the image of the area including the adhesive AD becomes darker over time for any type of light source. This is because the adhesive AD shrinks as it hardens, causing fine cracks in the adhesive AD and scattering the near-infrared light N2. To be more specific, as the adhesive AD hardens, the number of cracks increases. The near-infrared light N2 passes through the non-cracked parts of the adhesive AD and is scattered in the cracked parts, so that the intensity (amount of received light) of the light L received by the image sensor 3 decreases as the adhesive AD hardens. Therefore, as the adhesive AD hardens, the image of the area including the adhesive AD becomes darker.

[0039] In view of the above, when the user selects light source 22 as the light source to be used for evaluation, the user may evaluate that the curing of the adhesive AD progresses as the image of the area including the adhesive AD becomes darker.

[0040] In the evaluation device 1 and evaluation method described above, near-infrared light is irradiated onto the region AR including the adhesive AD of the resin structure RS, and the light L obtained by irradiating the region AR with the near-infrared light is converted into a plurality of pixel values, and an image based on the plurality of pixel values ​​is displayed on the display 5 for evaluation of the cured state. In general, the adhesive AD undergoes physical changes over time during the curing process. For example, the adhesive AD such as a cyanoacrylate adhesive and an epoxy adhesive shrinks as it cures, and the volume of the adhesive AD decreases. At this time, cracks may occur on the surface of the adhesive AD. For this reason, it can be said that the more cracks there are, the more the adhesive AD has cured.

[0041] The near-infrared light passes through the parts of the adhesive where no cracks have occurred and is scattered in the parts where cracks have occurred. Therefore, when the near-infrared light N1 is irradiated to the area AR from the same side as the image sensor 3, the pixel value of the cracked part increases, and when the near-infrared light N2 is irradiated to the area AR from the opposite side to the image sensor 3, the pixel value of the cracked part decreases. In this way, the occurrence of cracks is reflected in the pixel value, so it is possible to evaluate the curing state of the adhesive AD based on multiple pixel values ​​without analyzing the spectrum of the near-infrared light.

[0042] The resin bodies R1, R2 may be opaque in the visible light region. When the resin bodies R1, R2 that are opaque in the visible light region are used, the adhesive AD cannot be observed from the outside of the resin structure RS. However, the evaluation device 1 and the evaluation method use near-infrared light that transmits through the resin bodies R1, R2, so there is no need to destroy the resin structure RS. By simply placing the resin structure RS on the sample stage SS, it is possible to perform a non-destructive evaluation without contacting the resin structure RS with any part other than the sample stage SS of the evaluation device 1. Therefore, the cured state of the adhesive AD can be evaluated in real time in a non-destructive and non-contact manner. This makes it possible to inspect all actual products. From the above, the evaluation device 1 makes it possible to efficiently evaluate the cured state of the adhesive AD in the resin structure RS.

[0043] In a conventional evaluation method using near-infrared spectroscopy, the cured state of the adhesive is evaluated based on a change in the peak value of the spectrum in an area AR including the adhesive AD. On the other hand, in the evaluation device 1 and the evaluation method using the evaluation device 1, the entire area AR including the adhesive AD can be evaluated based on pixel values. Therefore, the area AR can be recognized two-dimensionally, which makes it possible to improve the evaluation accuracy of the cured state of the adhesive AD.

[0044] In the evaluation device 1 and the evaluation method using the evaluation device 1, since there is no need to measure the spectrum of light, it is possible to evaluate the cured state of the adhesive AD even when, for example, the amount of adhesive AD is so small that the spectrum cannot be measured, or when there are only small changes that cannot be detected by spectrum measurement.

[0045] The display 5 displays an image corresponding to a plurality of pixel values. With this configuration, the user of the evaluation device 1 can recognize the entire area AR including the adhesive AD in the image. Therefore, the user of the evaluation device 1 can evaluate the cured state of the adhesive AD simply by visually checking the image. Therefore, the cured state of the adhesive AD can be easily evaluated.

[0046] The light source 21 irradiates the resin structure RS with near-infrared light N1 in the region AR from the same side as the image sensor 3. When the light source 21 is selected as the light source to be used for evaluation, the image sensor 3 receives the scattered light scattered in the region AR as light L. As described above, the near-infrared light passes through the portion of the adhesive AD where no cracks have occurred and is scattered in the portion where cracks have occurred. Therefore, the scattered light becomes stronger as the number of cracks increases. Therefore, according to the above configuration, the scattered light generated in the portion where cracks have occurred can be received as light L, so the pixel value of the portion increases. In this way, the occurrence of cracks is reflected in the pixel value, so that it is possible to evaluate the curing state of the adhesive AD based on multiple pixel values ​​without analyzing the spectrum of the near-infrared light.

[0047] The light source 22 irradiates the resin structure RS with near-infrared light N2 from the opposite side to the image sensor 3 to the region AR. When the light source 22 is selected as the light source to be used for evaluation, the image sensor 3 receives the transmitted light that has passed through the region AR as light L. As described above, the near-infrared light passes through the portion of the adhesive where no cracks have occurred and is scattered in the portion where the cracks have occurred. For this reason, the amount of light that can pass through the adhesive AD decreases as the cracks increase, and the transmitted light becomes weaker. Therefore, according to the above configuration, the transmitted light that has passed through the portion other than the portion where the cracks have occurred can be received as light L, so the pixel value of the portion where the cracks have occurred becomes smaller. In this way, since the occurrence of the cracks is reflected in the pixel value, it is possible to evaluate the cured state of the adhesive AD based on multiple pixel values ​​without analyzing the spectrum of the near-infrared light. According to this configuration, even if one of the materials is a material that does not transmit near-infrared light, such as when a resin body and a metal body are bonded with the adhesive AD, the cured state of the adhesive AD can be evaluated.

[0048] Both the light source 21 and the light source 22 can irradiate near-infrared light in a wavelength range of 800 nm to 2500 nm. Near-infrared light in this wavelength range easily transmits through the resin bodies R1 and R2, making it possible to more reliably evaluate the cured state of the adhesive AD.

[0049] As a process for evaluating the cured state of the adhesive AD, the control device 4 may evaluate the cured state of the adhesive AD based on the multiple pixel values ​​instead of displaying an image corresponding to multiple pixel values ​​on the display 5.

[0050] With reference to Figs. 6 and 7, a method for evaluating the cured state of the adhesive AD by the control device 4 will be specifically described. Fig. 6 is a diagram for explaining the evaluation by the control device shown in Fig. 1. Fig. 7 is a diagram showing the change over time in the number of black pixels in a processing area PA described later in a binarized image. The upper part of Fig. 6 shows the same images as those shown in Fig. 5, which are taken 0 minutes, 60 minutes, and 600 minutes after adhesion when a halogen light source is used as the light source 22. The horizontal axis of Fig. 7 shows the elapsed time (unit: minutes) from adhesion. The vertical axis of Fig. 7 shows the ratio (unit: %) of the number of black pixels in the processing area PA described later. The ratio of the number of black pixels is calculated by the formula (number of black pixels in the processing area PA)÷(total number of pixels in the processing area PA)×100.

[0051] First, the control device 4 binarizes each of the multiple pixel values ​​received from the image sensor 3. For example, as shown in FIG. 6, the control device 4 determines a processing area PA in which binarization processing is performed in the obtained image. Here, the control device 4 determines an image area corresponding to the area AR as the processing area PA. Then, for each pixel value of the pixels included in the processing area PA, the control device 4 converts pixel values ​​equal to or greater than a predetermined threshold to white, and converts pixel values ​​less than the threshold to black. Through this process, each image in the upper row of FIG. 6 is converted into a binarized image like each image in the lower row of FIG. 6.

[0052] Next, the control device 4 counts the number of pixel values ​​having one of two values ​​(black and white) in the processing area PA. Here, the control device 4 counts the number of black pixels in the processing area PA. In the example shown in FIG. 6, the number of black pixels is 4170 in the image after 0 minutes, 12753 in the image after 60 minutes, and 26404 in the image after 600 minutes, and increases with time. As described above, when the light source 22 is used as the light source used for evaluation, as the curing of the adhesive AD progresses, the image of the area including the adhesive AD becomes black. Therefore, as the curing of the adhesive AD progresses, the number of white pixels decreases and the number of black pixels increases in the binarized image in the processing area PA. Therefore, the number of black pixels in the processing area PA can reflect the curing state of the adhesive AD.

[0053] Next, the control device 4 evaluates the curing state of the adhesive AD based on the count value of one of the two values ​​(black and white) in the processing area PA. As shown in FIG. 6, as the curing of the adhesive AD progresses, the number of black pixels increases. For example, a judgment value of the count value may be set in advance for each degree of curing of the adhesive AD. In this case, the control device 4 judges the degree of curing of the adhesive AD by comparing the count value with each judgment value. Specifically, the control device 4 judges the degree of curing of the adhesive AD to be the degree of curing corresponding to the judgment value closest to the count value.

[0054] As shown in FIG. 7, as the curing of the adhesive AD progresses, the ratio of the number of black pixels in the processing area PA increases. For example, a judgment value for the ratio may be set in advance for each degree of curing of the adhesive AD. In this case, the control device 4 judges the degree of curing of the adhesive AD by comparing each judgment value with the ratio calculated by dividing the count value by the total number of pixels included in the processing area PA. Specifically, the control device 4 judges the degree of curing of the adhesive AD to be the degree of curing corresponding to the judgment value closest to the calculated ratio.

[0055] As shown in FIG. 7, as the curing of the adhesive AD progresses, the rate of increase per unit time of the proportion of the number of black pixels in the processing area PA decreases. For example, a judgment value of the increase rate may be set in advance for each degree of curing of the adhesive AD. In this case, the control device 4 acquires a plurality of pixel values ​​from the image sensor 3 at a predetermined time interval and calculates the increase rate. Then, the control device 4 compares the calculated increase rate with each judgment value to judge the curing degree of the adhesive AD. Specifically, the control device 4 judges the curing degree corresponding to the judgment value closest to the calculated increase rate as the curing degree of the adhesive AD.

[0056] Then, the control device 4 outputs the evaluation result of the cured state of the adhesive AD (e.g., the degree of curing). For example, the control device 4 causes the display 5 to display the evaluation result. This completes the evaluation of the cured state of the adhesive AD by the control device 4. Note that the number of white pixels may be used instead of the number of black pixels.

[0057] Next, the accuracy of evaluation of the cured state of the adhesive AD by the control device 4 will be described with reference to Figs. 7 and 8. Fig. 8 is a diagram showing the change over time of the peak intensity ratio measured by near-infrared spectroscopy. The horizontal axis of Fig. 8 indicates the elapsed time (unit: minutes) from bonding. The vertical axis of Fig. 8 indicates the peak ratio intensity. The method of evaluating the cured state of the adhesive AD by near-infrared spectroscopy involves analyzing the near-infrared diffuse reflectance spectrum obtained by irradiating the resin structure RS with near-infrared light, and tracking the change in the peak value.

[0058] In the example shown in Fig. 8, ABS resin was used as the constituent material of the resin body R1 and the resin body R2, and a cyanoacrylate adhesive was used as the adhesive AD. The peak intensity ratio, which is the ratio (NA / NB) of the intensity NA of the near-infrared light at 1610 nm (peak A) to the intensity NB of the near-infrared light at 1718 nm (peak B), was calculated every 30 minutes and the peak intensity ratio was monitored. As shown in Fig. 8, the peak intensity ratio increases over time. In other words, as the curing of the adhesive AD progresses, the peak intensity ratio increases.

[0059] Here, when comparing the graphs of Fig. 7 and Fig. 8, it can be seen that the increasing trends of the graphs are similar. In other words, it is suggested that the evaluation method shown in Fig. 7 can evaluate the cured state of adhesive AD with the same accuracy as the evaluation method using near-infrared spectroscopy.

[0060] As described above, the control device 4 evaluates the cured state of the adhesive AD based on a plurality of pixel values. In this configuration, since the control device 4 evaluates the cured state of the adhesive AD, it becomes possible to objectively evaluate the cured state of the adhesive AD. Furthermore, the control device 4 binarizes each of the plurality of pixel values, and evaluates the cured state of the adhesive AD based on the number of pixel values ​​having any one of the values. According to this configuration, since the evaluation is based on the number of pixel values ​​having any one of the values ​​among the binarized pixel values, the cured state of the adhesive AD is quantitatively evaluated.

[0061] The evaluation device and evaluation method according to the present disclosure are not limited to the above-described embodiments.

[0062] For example, the evaluation device 1 may not include either the light source 21 or the light source 22. In the above embodiment, the light source 21 and the light source 22 are fixed. Instead of this configuration, the evaluation device 1 may include the light source 21 and a moving mechanism that moves the light source 21. The moving mechanism may move the light source 21 between a position where the near-infrared light N1 is irradiated onto the region AR from the same side as the image sensor 3, and a position where the near-infrared light N1 is irradiated onto the region AR from the opposite side to the image sensor 3.

[0063] As a process for evaluating the cured state of the adhesive AD, the control device 4 may, in addition to displaying an image corresponding to multiple pixel values ​​on the display 5, evaluate the cured state of the adhesive AD based on the multiple pixel values.

[0064] (Additional Note) [Clause 1] 1. An evaluation device for evaluating a cured state of an adhesive in a resin structure obtained by bonding a plurality of resin bodies with the adhesive, comprising: a light source that irradiates a region of the resin structure containing the adhesive with near-infrared light; a conversion unit that receives light obtained by irradiating the region with the near-infrared light and converts the light into a plurality of pixel values; A control unit that performs processing for evaluating the curing state using the plurality of pixel values; An evaluation device comprising:

[0065] [Clause 2] a display unit that displays an image corresponding to the plurality of pixel values, Item 1. The evaluation device according to item 1, wherein the control unit causes the image to be displayed on the display unit.

[0066] [Clause 3] The evaluation device according to clause 1 or 2, wherein the control unit evaluates the curing state based on the plurality of pixel values.

[0067] [Article 4] The evaluation device according to clause 3, wherein the control unit binarizes each of the plurality of pixel values ​​and evaluates the curing state based on the number of pixel values ​​having any one of the values.

[0068] [Article 5] The light source irradiates the near-infrared light onto the region from the same side as the conversion unit, 5. The evaluation device according to any one of clauses 1 to 4, wherein the conversion section receives, as the light, light scattered in the region.

[0069] [Article 6] The light source irradiates the near-infrared light onto the region from an opposite side to the conversion unit, 6. The evaluation device according to any one of clauses 1 to 5, wherein the conversion section receives, as the light, transmitted light that has passed through the region.

[0070] [Article 7] 1. A method for evaluating a cured state of an adhesive in a resin structure obtained by bonding a plurality of resin bodies with an adhesive, comprising: irradiating a region of the resin structure containing the adhesive with near-infrared light; receiving light obtained by irradiating the area with the near-infrared light and converting the light into a plurality of pixel values; performing a process for evaluating the curing state using the plurality of pixel values; (c) evaluation methods; [Explanation of symbols]

[0071] 1... evaluation device, 21... light source, 22... light source, 3... image sensor (conversion unit), 4... control device (control unit), 5... display (display unit), R1, R2... resin body, AD... adhesive, RS... resin structure, SS... sample stage, AR... area, N1, N2... near-infrared light, L... light.

Claims

1. 1. An evaluation device for evaluating a cured state of an adhesive in a resin structure obtained by bonding a plurality of resin bodies with the adhesive, comprising: a light source that irradiates a region of the resin structure that contains the adhesive with near-infrared light; a conversion unit that receives light obtained by irradiating the region with the near-infrared light and converts the light into a plurality of pixel values; A control unit that performs processing for evaluating the curing state using the plurality of pixel values; An evaluation device comprising:

2. a display unit that displays an image corresponding to the plurality of pixel values, The evaluation device according to claim 1 , wherein the control unit causes the image to be displayed on the display unit.

3. The evaluation device according to claim 1 , wherein the control unit evaluates the curing state based on the plurality of pixel values.

4. The evaluation device according to claim 3 , wherein the control unit binarizes each of the plurality of pixel values, and evaluates the curing state based on the number of pixel values ​​having any one of the values.

5. The light source irradiates the near-infrared light onto the region from the same side as the conversion unit, The evaluation device according to claim 1 , wherein the conversion section receives, as the light, light scattered in the region.

6. The light source irradiates the near-infrared light onto the region from an opposite side to the conversion unit, The evaluation device according to claim 1 , wherein the conversion section receives, as the light, light transmitted through the region.

7. 1. A method for evaluating a cured state of an adhesive in a resin structure obtained by bonding a plurality of resin bodies with the adhesive, comprising: irradiating a region of the resin structure containing the adhesive with near-infrared light; receiving light obtained by irradiating the area with the near-infrared light and converting the light into a plurality of pixel values; performing a process for evaluating the curing state using the plurality of pixel values; (c) evaluation methods;

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