Observation method and observation device

Abstract

In the present observation method, measurement values ​​of a measurement object at different multiple positions in a plane intersecting with a depth direction are acquired from an optical coherence tomography apparatus (S100). In the present observation method, at each of the multiple positions, the measurement value is integrated in the depth direction (S104). In the present observation method, at each of the multiple positions, a contraction parameter of the measurement object is calculated based on the integrated value (S105).

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Japanese Patent Application No. 2018-175126 filed with the Japan Patent Office on September 19, 2018, the disclosure of which is hereby incorporated by reference in its entirety. Technical Field

[0003] The present disclosure relates to an observation method and an observation device. Background Art

[0004] Ceramics are excellent in various physical properties such as hardness, heat resistance, corrosion resistance, and electrical insulation, etc. Therefore, ceramic structures manufactured to achieve functions required in specific applications are being used for various purposes.

[0005] The ceramic structure is made by performing steps such as a mixing step, a molding step, a drying step, and a firing step on the raw materials (see Patent Document 1). The ceramic structure being manufactured shrinks during the steps such as the drying step and the firing step. The shrunk structure is ground to meet the required size. The shrunk structure is hard, and grinding takes time. Therefore, the size of the structure before shrinkage in the molding step (hereinafter, referred to as a "molded body") is determined so that the structure is as close as possible to the required size after shrinkage.

[0006] The shrinkage during the manufacturing process varies depending on factors such as the properties of the molded body. Therefore, even with the same mixing, the size of the molded body to be determined varies with each batch of mixed raw materials. In the molding step of the prior art, an intermediate molded body is molded by a rubber press or the like, the shrinkage rate is estimated by inspecting the intermediate molded body, the size of the molded body is determined based on the shrinkage rate, and the intermediate molded body is cut to a size that matches the size of the molded body. Inspection of the intermediate molded body takes a relatively long time. Therefore, a portion of the intermediate molded body made of the same batch of mixed raw materials is extracted to inspect the portion of the intermediate molded body, and the shrinkage rate estimated based on the inspection is used as the shrinkage rate of the molded body of the same batch to adjust the cutting conditions such as the cutting amount.

[0007] Citation List

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Publication No. 2017-170869 Summary of the invention

[0010] The observation method according to the first aspect comprises:

[0011] acquiring, from the optical coherence tomography imager, measurement values ​​of the measurement object at a plurality of different positions in a plane intersecting the depth direction;

[0012] calculating an integrated value by integrating the measured value in the depth direction at each of the plurality of positions; and

[0013] At each of the plurality of positions, a contraction parameter of the measurement object is calculated based on the integrated value.

[0014] Furthermore, the observation device according to the second aspect comprises:

[0015] A controller is provided for acquiring, from an optical coherence tomography imager, measurement values ​​of a measurement object at different multiple positions in a plane intersecting a depth direction; at each of the multiple positions, calculating an integral value by integrating the measurement values ​​in the depth direction; and at each of the multiple positions, calculating a contraction parameter of the measurement object based on the integral value. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In the attached picture:

[0017] Figure 1 is a functional block diagram showing a schematic configuration of an observation system including an observation apparatus according to the embodiment;

[0018] Figure 2 It shows Figure 1 A diagram showing the relationship between the measured value calculated by the controller of the optical coherence tomography apparatus and the depth direction;

[0019] Figure 3 It is used to illustrate Figure 1 A diagram of measurements calculated at multiple locations by an optical coherence tomography instrument in FIG.

[0020] Figure 4 It is used to illustrate Figure 1 A diagram showing how a controller of an observation device in FIG. 1 aligns a depth position as a peak value of a measurement value with a reference position;

[0021] Figure 5 It is used to illustrate Figure 1 A diagram showing how a controller of an observation device in FIG. 1 calculates an integrated value by integrating measurement values ​​detected at a plurality of positions in a depth direction;

[0022] Figure 6 is a graph for explaining a calibration curve showing a corresponding relationship between an integral value of a measured value and a green embryo density;

[0023] Figure 7 It shows that Figure 1 A diagram of an example of parameters displayed on a display in; and

[0024] Figure 8 Is used to illustrate the Figure 1 Flowchart of a graph creation process performed by a controller of an observation device in FIG. DETAILED DESCRIPTION

[0025] Hereinafter, an embodiment of an observation device to which the present disclosure is applied will be described with reference to the drawings.

[0026] like Figure 1 As shown in FIG. 1 , an observation system 11 including an observation device 10 according to an embodiment of the present disclosure is configured to include an optical coherence tomography imager 12 and the observation device 10. The observation system 11 observes, for example, a molded body as a measurement object obj, which is an intermediate of a ceramic structure. Note that in Figure 1 In FIG. 1 , the solid lines with arrows connecting the functional blocks show the travel of the light beam. Figure 1 In FIG. 1 , the dotted lines connecting the functional blocks show the flow of control signals or communication information. The communication indicated by the dotted lines may be wired communication or wireless communication.

[0027] The optical coherence tomography imager 12 captures images from the surface of the measurement object obj to a maximum depth of about 10 mm by optical coherence tomography (OCT). In the embodiment, the optical coherence tomography imager 12 is a wavelength sweeping OCT device, but it can also be another type of OCT device. The optical coherence tomography imager 12 includes a light source 13, a beam splitter 14, a reference mirror 15, a scanner 16, a detector 17, and a controller 18.

[0028] For example, the light source 13 emits light in a frequency band detectable by the detector 17, such as light in a near-infrared band. The light source 13 may be a wavelength swept type light source, and may repeatedly emit light of a wavelength that varies within a predetermined range along the time axis. Note that in a configuration in which the optical coherence tomography imager 12 is an OCT device of a type other than the wavelength swept type, the light source 13 may be a light source corresponding to the type. For example, the light source 13 includes a collimating lens, and emits collimated light having a narrower diameter.

[0029] A beam splitter 14 is provided in the emission direction of the light source 13. For example, the beam splitter 14 is a half mirror. The beam splitter 14 separates the light emitted from the light source 13 and causes the light to travel in two directions. In addition, the beam splitter 14 causes coherent light obtained by mixing the reference light incident from the reference mirror 15 with the signal light incident from the measurement object obj to travel toward the detector 17.

[0030] The reference mirror 15 is provided in one of the traveling directions of the light separated by the beam splitter 14. The reference mirror 15 is arranged so that the mirror plane is perpendicular to the traveling direction, and reflects the incident light toward the beam splitter 14 as reference light.

[0031] The scanner 16 scans the measuring object obj by using the light that travels in a direction different from the reference mirror 15 among the light separated by the beam splitter 14 as the irradiation light. The scanner 16 can scan by any of various mechanisms. For example, the scanner 16 can scan by reflecting the irradiation light while changing the reflection direction using a reflective member such as a galvanometer mirror. In addition, the scanner 16 can also scan by changing the irradiation position of the irradiation light on the surface of the measuring object obj using a movable stage.

[0032] The scanner 16 can scan the measuring object obj in a predetermined area on the irradiation surface of the measuring object obj. For example, the predetermined area can have a square shape. For example, the measuring object obj can be scanned by any of various methods (such as raster scanning, vector scanning, or spiral scanning). In an embodiment, the measuring object obj is scanned by raster scanning.

[0033] Note that in the optical coherence tomography imager 12, the measuring object obj is set so that the irradiation light irradiates the measuring object obj at an incident angle equal to or greater than 0°. The irradiation light irradiating each position of the measuring object obj by the scanner 16 advances from the surface in the depth direction while being attenuated due to absorption, and is reflected and scattered at each depth position. The reflected and scattered signal light is incident on the beam splitter 14.

[0034] The detector 17 receives the coherent light traveling from the beam splitter 14. The detector 17 outputs a measurement signal having an intensity corresponding to the amount of the received light.

[0035] The controller 18 includes one or more processors and a memory. The processor may include a general-purpose processor that performs a specific function by loading a specific program, and a dedicated processor dedicated to a specific process. The dedicated processor may include an application-specific integrated circuit (ASIC). The processor may also include a programmable logic device (PLD). The PLD may include a field programmable gate array (FPGA). The controller 18 may also be a system on chip (SoC) or a packaged system (SiP) in which one or more processors cooperate.

[0036] The controller 18 calculates the following by performing inverse Fourier transform on the measurement signal obtained from the detector 17: Figure 2The controller 18 uses the reflected light intensity in the depth direction at any irradiation position EP of the irradiation light EL as a measured value. The controller 18 identifies the irradiation position EP in the plane intersecting with the depth direction, which overlaps with the irradiation direction of the irradiation light EL, by acquiring the position information from the scanner 16. The controller 18 outputs the irradiation position EP and the reflected light intensity in the depth direction to the observation device 10 in association with each other.

[0037] The observation device 10 includes a controller 19 , a storage device 20 , and a display 21 .

[0038] The controller 19 includes one or more processors and a memory. The processor may include a general-purpose processor that performs a specific function by loading a specific program, and a dedicated processor dedicated to a specific process. The dedicated processor may include an application-specific integrated circuit (ASIC). The processor may also include a programmable logic device (PLD). The PLD may include an FPGA. The controller 19 may also be a SoC or SiP in which one or more processors cooperate.

[0039] like Figure 3 As shown in , the controller 19 acquires the measurement values ​​of the measurement object obj at a plurality of different positions in a plane intersecting the depth direction, or in other words, at a plurality of irradiation positions EP from the optical coherence tomography imager 12. Note that in the present embodiment, as described above, the measurement value of the measurement object obj is the reflected light intensity along the depth direction. The controller 19 may cause the storage device 20 to store the acquired measurement value along the depth direction at each of the plurality of positions.

[0040] The controller 19 may detect the position in the depth direction where a peak appears in the measurement value of the measurement object obj at each of the plurality of positions as the peak position. Figure 4 As shown in , the controller 19 may align a reference position in the depth direction of a measurement value of the measuring object obj at each of a plurality of positions (eg, from a first irradiation position to a fifth irradiation position) with the detected peak position.

[0041] like Figure 5 As shown in , the controller 19 integrates the measured values ​​in the depth direction at each of the plurality of positions to calculate an integrated value. Note that when calculating the integrated value, the controller 19 may integrate the measured values ​​included in the range of predetermined depth positions. The range of predetermined depth positions when calculating the integrated value may be a range of depth positions in a coordinate system with a reference point in the optical coherence tomography imager 12 at each of the plurality of positions as an origin, or a range of the same depth position based on a peak position in the depth direction.

[0042] Based on the integral value, the controller 19 calculates the shrinkage parameter of the measuring object obj at each of the plurality of positions. Note that the shrinkage parameter is any variable representing the internal state of the molded part as the measuring object obj, and the shrinkage parameter affects the degree of shrinkage of the measuring object obj when it is dried and fired. The shrinkage parameter is a parameter such as the green density or porosity of the molded part. The integral value is related to the shrinkage parameter such as the green density and may vary depending on the density of the molded part. Therefore, the controller 19 may calculate the shrinkage parameter by using a calibration curve (such as Figure 6 The contraction parameters were calculated by conversion from the integrated values ​​using the calibration curve shown in ).

[0043] like Figure 7 As shown in , the controller 19 can create a parameter map PM, which shows the contraction parameters calculated at each of the multiple positions in association with the multiple positions in the plane. Note that the controller 19 can create an integral value map, which shows the integral values ​​calculated at each of the multiple positions in association with the multiple positions in the plane.

[0044] The controller 19 reports the shrinkage parameters calculated at each of the plurality of positions to the ceramic structure manufacturing device. Based on the reported shrinkage parameters, the manufacturing device determines the cutting conditions for the measurement object obj for which the shrinkage parameters have been calculated. The manufacturing device cuts the measurement object obj under the determined cutting conditions, and manufactures the ceramic structure by undergoing a drying step and a firing step. Note that the controller 19 may also calculate the cutting conditions based on the shrinkage parameters. In a configuration in which the controller 19 calculates the cutting conditions, the controller 19 controls the manufacturing device to cut the measurement object obj according to the calculated cutting conditions.

[0045] The storage device 20 includes any type of storage device such as a random access memory (RAM) and a read only memory (ROM), for example. The storage device 20 stores various programs for causing the controller 19 to function, and various information used by the controller 19.

[0046] For example, the storage device 20 stores the reflected light intensity in the depth direction at each of the plurality of positions for each measurement object obj. In addition, for example, the storage device 20 stores a calibration curve of the contraction parameter with respect to the integral value. In addition, for example, the storage device 20 stores the contraction parameter calculated for each measurement object obj at each of the plurality of positions.

[0047] The display 21 is a display such as a liquid crystal display or an organic EL display that displays an image. The display 21 can display at least one of the parameter map PM and the integrated value map created by the controller 19.

[0048] Next, we will use Figure 8 1 and 2 to describe the map creation process performed by the controller 19 in the embodiment. When the optical coherence tomography imager 12 starts measuring the measurement value of any measurement object obj, the map creation process starts together. Note that, for example, the controller 19 can recognize the start of measurement of the optical coherence tomography imager 12 by a synchronization signal obtained from the optical coherence tomography imager 12.

[0049] In step S100, the controller 19 acquires the measurement value of the measuring object obj at any irradiation position EP, or in other words, the reflected light intensity in the depth direction. After the acquisition, the process proceeds to step S101.

[0050] In step S101, the controller 19 detects the position in the depth direction where the peak appears in the measurement value acquired in step S100 as the peak position. After the peak position is detected, the process proceeds to step S102.

[0051] In step S102, the controller 19 determines whether measurement values ​​have been acquired at all positions where the measurement object obj is to be measured. Note that the controller 19 may determine whether measurement values ​​have been acquired at all positions based on a synchronization signal acquired from the optical coherence tomography imager 12, notification information indicating completion, or the like. In the case where measurement values ​​have not been acquired at all positions, the process returns to step S100. In the case where measurement values ​​have been acquired at all positions, the process proceeds to step S103.

[0052] In step S103, the controller 19 aligns the reference position in the depth direction of the measurement value at each of the plurality of positions with the peak position detected in step S101. After the reference positioning, the process proceeds to step S104.

[0053] In step S104, the controller 19 integrates the measured value within the range of a predetermined depth position, which is the position aligned with the reference position in step S103, to calculate an integrated value. After the integrated value is calculated, the process proceeds to step S105.

[0054] In step S105, the controller 19 calculates the contraction parameter at each of the plurality of positions based on the integrated value calculated in step S104. After the contraction parameter is calculated, the process proceeds to step S106.

[0055] In step S106, the controller 19 creates a parameter map PM and an integral value map showing the contraction parameter and integral value at each of the plurality of positions calculated in steps S104 and S105, respectively. After the parameter map PM and the integral value map are created, the process proceeds to step S107.

[0056] In step S107, the controller 19 causes the display 21 to display the parameter map PM and the integrated value map created in step S 106. After the parameter map PM and the integrated value map are displayed, the process proceeds to step S108.

[0057] In step S108, the controller 19 outputs the integrated value map and the parameter map PM created in step S106 to the manufacturing apparatus. After the integrated value map and the parameter map PM are output, the map creation process ends.

[0058] In the observation device 10 according to the present embodiment having the above-described configuration, the measurement values ​​of the measurement object obj measured at a plurality of positions by the optical coherence tomography imager 12 are used. Therefore, since the observation device 10 uses the measurement results from the optical coherence tomography imager 12 capable of rapid and non-invasive imaging, the observation device 10 can rapidly observe each measurement object obj that is finally processed into a finished product.

[0059] Moreover, the observation device 10 according to the embodiment integrates the measured value in the depth direction at each of the plurality of positions, and calculates the shrinkage parameter of the measurement object obj based on the integrated value. According to such a configuration, the observation device 10 can detect the parameters that affect the shrinkage in the steps such as the drying step and the firing step at each of the plurality of positions. Therefore, the observation device 10 can provide parameters that can be used to determine the manufacturing conditions such as the local temperature and humidity in at least one of the drying step and the firing step.

[0060] Furthermore, the observation device 10 according to the embodiment displays at least one of the parameter map PM and the integral value map. According to such a configuration, the observation device 10 can enable the operator to see the internal state at each of a plurality of positions in the measurement object obj.

[0061] In addition, the observation device 10 according to the present embodiment integrates the measured values ​​within a range of a predetermined depth position. Using the resolution capability of the optical coherence tomography, the surface of the measurement object obj can be detected with one or two pixels (or in other words, at one or two depth positions). The measured value obtained by detecting the surface of the measurement object obj with one pixel is greatly different in intensity from the measured value detected with two pixels. Therefore, the average value of the measured values ​​at the depth position corresponding to the surface where the intensity is particularly strong has a relatively low reliability as a measured value. On the other hand, the observation device 10 having the above configuration can integrate the measured values ​​within a range other than the depth position corresponding to the surface, and therefore, the estimation accuracy of the contraction of the measurement object obj based on the contraction parameter can be improved.

[0062] In addition, the observation device 10 according to the embodiment performs integration on the measured values ​​at the same depth position with reference to the peak position. In the optical coherence tomography imager 12, the surface of the measured object is tilted relative to the traveling direction of the irradiation light (or in other words, the depth direction) to reduce the strong back reflection detected from the surface of the measured object. As the irradiation light EL travels in the depth direction from the surface, the irradiation light EL irradiating the measured object obj is greatly attenuated, and therefore, as the depth position from the surface becomes longer, the intensity of the measured value also decreases. In response to this phenomenon, the observation device 10 having the above-mentioned configuration integrates the measured values ​​at the same depth position with reference to the peak position estimated as the surface position at each of the multiple positions, and therefore, even with the configuration in which the measured object obj is tilted relative to the depth direction, it is possible to calculate the contraction parameter limited to the range that greatly affects the contraction at each of the multiple positions.

[0063] Furthermore, in the observation apparatus 10 according to the embodiment, the integrated value is converted into a contraction parameter by using a calibration curve. Therefore, the observation apparatus 10 can reduce the processing load on the controller 19.

[0064] The present disclosure has been described based on the drawings and examples, but it should be noted that those skilled in the art can easily make various modifications and changes based on the present disclosure. Therefore, it should be noted that these modifications and changes are included in the scope of the present disclosure.

[0065] Although the foregoing discloses a system described as including various modules and / or units that perform specific functions, it should be noted that these modules and units are schematically shown to briefly describe their functions, and do not necessarily indicate specific hardware and / or software. In this sense, it is sufficient for these modules, units and other structural elements to be implemented as hardware and / or software that basically performs the specific functions described herein. The various functions of different structural elements can be combined or separated into hardware and / or software in any way, and each of the various functions of different structural elements can be used alone or in some combination with each other. In addition, devices such as keyboards, displays, touch screens and pointer devices are included, but the input / output, I / O devices or user interfaces not limited to the above devices can be directly or connected to the system through an intermediate I / O controller. In this way, various aspects of the content disclosed herein can be realized in many different modes, and these modes are all included in the scope of the content disclosed herein.

[0066] Reference numerals list

[0067] 10 Observation device

[0068] 11 Observation System

[0069] 12 Optical Coherence Tomography

[0070] 13 Light Source

[0071] 14 Beam splitter

[0072] 15 Reference mirror

[0073] 16 Scanner

[0074] 17 Detector

[0075] 18 Controller

[0076] 19 Controller

[0077] 20 Storage Device

[0078] 21 Display

[0079] EL irradiation light

[0080] EP irradiation location

[0081] Obj Measurement object

[0082] PM parameter diagram.

Claims

1. An observation method comprising: acquiring, from an optical coherence tomography device, measurement values ​​of a measurement object at different multiple positions in a plane intersecting with a depth direction, the measurement object being a ceramic molded body; calculating an integrated value by integrating the measured value in the depth direction at each of the plurality of positions; as well as At each of the plurality of positions, a green density of the molded body of the measurement object is calculated based on the integrated value.

2. The observation method according to claim 1, further comprising: A parameter map is displayed that shows, in association with the plurality of locations in the plane, a green density of the molded body calculated at each of the plurality of locations.

3. The observation method according to claim 1 or 2, wherein: Calculating the integrated value includes integrating the measured values ​​within a range of predetermined depth positions.

4. The observation method according to claim 3, further comprising: At each of the plurality of positions, a peak position of the measurement value in the depth direction is detected, wherein: Calculating the integrated value includes integrating, at each of the plurality of positions, the measurement values ​​within a range of the same depth position with reference to the peak position.

5. The observation method according to claim 1 or 2, wherein: A calibration curve is used to convert the integrated value into the green density of the shaped body.

6. The observation method according to claim 1 or 2, further comprising: An integrated value graph showing the integrated value calculated at each of the plurality of positions in association with the plurality of positions in the plane is displayed.

7. An observation device comprising: a controller that acquires measurement values ​​of a measurement object at different multiple positions in a plane intersecting a depth direction from an optical coherence tomography imager, the measurement object being a ceramic formed body; and calculates an integrated value by integrating the measurement value in the depth direction at each of the multiple positions; And at each of the plurality of positions, a green density of the molded body of the measurement object is calculated based on the integrated value.

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