Magnetic domain structure analysis device, magnetic domain structure analysis methods and for manufacturing a grain-oriented electromagnetic steel sheet, program for making a computer perform processing, grain-oriented electromagnetic steel sheet, and iron core

Description

MAGNETIC DOMAIN STRUCTURE ANALYSIS DEVICE, MAGNETIC DOMAIN STRUCTURE ANALYSIS METHODS AND FOR MANUFACTURING A GRAIN-ORIENTED ELECTROMAGNETIC STEEL SHEET, NON-TRANSIENTIAL COMPUTER-READABLE STORAGE MEDIUM, GRAIN-ORIENTED ELECTROMAGNETIC STEEL SHEET, AND IRON CORE Technical field

[001] The present description refers to a magnetic domain structure analysis device, a magnetic domain structure analysis method, a program, a method for manufacturing a grain-oriented electromagnetic steel sheet, a grain-oriented electromagnetic steel sheet and an iron core. Fundamentals of the Technique

[002] It is known that the width of a magnetic domain of a grain-oriented electromagnetic steel sheet is correlated with the iron loss when the grain-oriented electromagnetic steel sheets are stacked as a transformer. Therefore, determining the distribution of the width of the magnetic domains is important in the manufacture of grain-oriented electromagnetic steel sheets.

[003] For example, the following technique is known as a method for visualizing the magnetic domain structure of a grain-oriented electromagnetic steel sheet. Specifically, Japanese patent No. 5987610 describes a technique that, using magneto-optical elements that convert the magnetic domain structure into detectable optical features, acquires an image of the magnetic domain, which shows the magnetic domain structure, based on the optical features detected by the magneto-optical elements.

[004] In addition, the following technique is known as a method Petition 870250103202, dated 11 / 11 / 2025, page 9 / 103 / 37 to investigate the statistical properties of the magnetic domain structure of a grain-oriented electromagnetic steel sheet. Specifically, Japanese patent application (JP-A) No. 2021-169979 describes a technique for acquiring multiple partial Fourier images by performing the Fourier transform on multiple partial regions included in a magnetic domain image and deriving the width and orientation of a magnetic domain based on the peak positions of the points in the respective partial Fourier images. SUMMARY OF THE INVENTION Technical Problem

[005] However, the following problems arise when the Fourier transform is used to derive the width of a magnetic domain based on its image. That is, in a case where the width of the Fourier transform window (i.e., the size of the Fourier transform) is not an integer multiple of the width of the magnetic domain, the peaks of the spectrum become scattered and a precise peak value cannot be determined. Furthermore, in the Fourier transform, the spectra are in a uniform range on the frequency axis, but are in a non-uniform range when viewed by wavelength, and therefore the detection resolution of the width of a magnetic domain deteriorates, especially in locations where the widths of the magnetic domains are large.

[006] The present description was made in view of the circumstances described above, and one of its objectives is to provide a magnetic domain structure analysis device, a magnetic domain structure analysis method, and a program that can accurately measure the width of a magnetic domain compared to a case using the Fourier transform. Furthermore, an objective of the present description is to provide a method for manufacturing an electromagnetic steel sheet. Petition 870250103202, dated 11 / 11 / 2025, page 10 / 103 / 37 oriented grain that allows obtaining an oriented grain electromagnetic steel sheet in which the distortion of the magnetostriction waveform is small, while the iron loss is effectively reduced. Furthermore, an objective of the present description is to provide an oriented grain electromagnetic steel sheet and an iron core in which the distortion of the magnetostriction waveform is small, while the iron loss is effectively reduced. Solution to the Problem

[007] A first aspect of the present description is a magnetic domain structure analysis device, including: a magnetic domain image acquisition section that acquires a magnetic domain image by imaging a grain-oriented electromagnetic steel plate;and a magnetic domain width measurement section that measures the width of a magnetic domain of grain-oriented electromagnetic steel sheet based on the magnetic domain image, wherein the magnetic domain width measurement section generates multiple filter cores of different spatial sizes, multiplying a complex one-dimensional Gabor filter by A in a spatial direction corresponding to a direction orthogonal to the lamination direction of the grain-oriented electromagnetic steel sheet, and by 1 / A in an amplitude direction, applies the multiple filter cores respectively to the magnetic domain image and calculates an absolute value of the filter output per filter core, and derives the magnetic domain width of the grain-oriented electromagnetic steel sheet based on the spatial size of the filter core whose absolute value is the largest among the multiple filter cores.

[008] A second aspect of the present description is a magnetic domain structure analysis device, in which the magnetic domain structure analysis device related to the first aspect includes a magnetic domain orientation measurement section that measures the Petition 870250103202, dated 11 / 11 / 2025, page 11 / 103 / 37 orientation of the magnetic domain of the grain-oriented electromagnetic steel sheet based on the magnetic domain image, where the magnetic domain orientation measurement section generates several sets of differentiated filter cores, differentiating two-dimensional Gaussian functions of different spatial sizes in an X direction that corresponds to the direction orthogonal to the rolling direction of the grain-oriented electromagnetic steel sheet and in a Y direction that corresponds to the rolling direction of the grain-oriented electromagnetic steel sheet, for each of the two-dimensional Gaussian functions, applies the various sets of differentiated filter cores, respectively,The magnetic domain image is used to calculate the square roots of the sums of squares of the respective filter outputs of the differentiated filter cores from the various sets, and the orientation of the magnetic domain of the grain-oriented electromagnetic steel sheet is derived based on the respective filter outputs of the differentiated filter cores from the set that has the largest square root of the sum of squares among the various sets of differentiated filter cores.

[009] A third aspect of the present description is a magnetic domain structure analysis device, in which the magnetic domain structure analysis device related to the second aspect includes a magnetic domain width correction section that corrects the magnetic domain width of the grain-oriented electromagnetic steel sheet, measured by the magnetic domain width measurement section, based on the magnetic domain orientation of the grain-oriented electromagnetic steel sheet, measured by the magnetic domain orientation measurement section.

[0010] A fourth aspect of the present description is a method for analyzing the magnetic domain structure, including: a magnetic domain imaging step that acquires a domain image. Petition 870250103202, dated 11 / 11 / 2025, p.12 / 103 / 37 magnetic by means of an image of a grain-oriented electromagnetic steel sheet; and a magnetic domain width measurement step to measure the width of a magnetic domain based on the magnetic domain image, wherein the magnetic domain width measurement step generates multiple filter cores of different spatial sizes, multiplying a complex one-dimensional Gabor filter by A in a spatial direction corresponding to a direction orthogonal to the lamination direction of the grain-oriented electromagnetic steel sheet, and by 1 / A in an amplitude direction, applies the multiple filter cores respectively to the magnetic domain image and calculates an absolute value of the filter output per filter core, and derives the magnetic domain width of the grain-oriented electromagnetic steel sheet based on the spatial size of the filter core whose absolute value is the largest among the multiple filter cores.

[0011] A fifth aspect of the present description is a method for analyzing the magnetic domain structure, in which the method for analyzing the magnetic domain structure related to the fourth aspect includes a magnetic domain orientation measurement step to measure the magnetic domain orientation of the grain-oriented electromagnetic steel sheet based on the magnetic domain image, wherein the magnetic domain orientation measurement step generates several sets of differentiated filter cores, differentiating two-dimensional Gaussian functions of different spatial sizes in an X direction that corresponds to the direction orthogonal to the rolling direction of the grain-oriented electromagnetic steel sheet and in a Y direction that corresponds to the rolling direction of the grain-oriented electromagnetic steel sheet, for each of the two-dimensional Gaussian functions, applies the various sets of differentiated filter cores, respectively,based on the magnetic domain image and calculates the square roots of the sums of the squares of the respective outputs of the differentiated filter cores of the various, Petition 870250103202, dated 11 / 11 / 2025, page 13 / 103 / 37 sets and derives the orientation of the magnetic domain of the grain-oriented electromagnetic steel sheet based on the respective outputs of the differentiated filter cores of the set that has the largest square root of the sum of the squares, among the various sets of differentiated filter cores.

[0012] A sixth aspect of the present description is a method of magnetic domain structure analysis, in which the magnetic domain structure analysis method related to the fifth aspect includes a magnetic domain width correction step to correct the magnetic domain width of the grain-oriented electromagnetic steel sheet, which was measured by the magnetic domain width measurement step, based on the magnetic domain orientation of the grain-oriented electromagnetic steel sheet, which was measured by the magnetic domain orientation measurement step.

[0013] A seventh aspect of the present description is a program for making a computer perform processing, which includes: a magnetic domain image acquisition step, which consists of acquiring a magnetic domain image by means of an image of a grain-oriented electromagnetic steel plate;and a magnetic domain width measurement step, which consists of measuring the width of a magnetic domain based on the magnetic domain image, wherein the magnetic domain width measurement step generates multiple filter cores of different spatial sizes, multiplying a complex one-dimensional Gabor filter by A in a spatial direction corresponding to a direction orthogonal to the lamination direction of the grain-oriented electromagnetic steel sheet, and by 1 / A in an amplitude direction, applies the multiple filter cores respectively to the magnetic domain image and calculates an absolute value of the filter output per filter core, and derives the magnetic domain width of the electromagnetic steel sheet from; Petition 870250103202, dated 11 / 11 / 2025, page 14 / 103 / 37 oriented grain based on the spatial size of the filter core whose absolute value is the largest among the multiple filter cores.

[0014] An eighth aspect of the present description is a program in which, in the program relating to the seventh aspect, the processing includes a magnetic domain orientation measurement step to measure the magnetic domain orientation of the grain-oriented electromagnetic steel sheet based on the magnetic domain image, wherein the magnetic domain orientation measurement step generates several sets of differentiated filter cores, differentiating two-dimensional Gaussian functions of different spatial sizes in an X direction that corresponds to the direction orthogonal to the rolling direction of the grain-oriented electromagnetic steel sheet and in a Y direction that corresponds to the rolling direction of the grain-oriented electromagnetic steel sheet, for each of the two-dimensional Gaussian functions, applies the various sets of differentiated filter cores, respectively,The magnetic domain image is used to calculate the square roots of the sums of squares of the respective filter outputs of the differentiated filter cores from the various sets, and the orientation of the magnetic domain of the grain-oriented electromagnetic steel sheet is derived based on the respective filter outputs of the differentiated filter cores from the set that has the largest square root of the sum of squares among the various sets of differentiated filter cores.

[0015] A ninth aspect of the present description is a program in which, in the program related to the eighth aspect, the processing includes a magnetic domain width correction step to correct the magnetic domain width of the grain-oriented electromagnetic steel sheet that was measured by the magnetic domain width measurement step, based on the magnetic domain orientation of the grain-oriented electromagnetic steel sheet that was measured by the measurement step of Petition 870250103202, dated 11 / 11 / 2025, page 15 / 103 / 37 guidance of the magnetic domain.

[0016] A tenth aspect of the present description is a method of manufacturing a grain-oriented electromagnetic steel sheet, including: a magnetic domain structure analysis step, which consists of performing a magnetic domain structure analysis, including deriving the width of a magnetic domain of a grain-oriented electromagnetic steel sheet, using the magnetic domain structure analysis method of any of the aspects described between the fourth and sixth; and a groove or thermal deformation formation step for, based on the analysis results obtained in the magnetic domain structure analysis step, irradiating a laser beam onto a surface of the grain-oriented electromagnetic steel sheet being transported in a transport direction, thereby forming several grooves or thermal deformations extending in a direction that intersects the transport direction, at intervals in that direction.

[0017] An eleventh aspect of the present description is a method of manufacturing a grain-oriented electromagnetic steel sheet, in which, in the method of manufacturing a grain-oriented electromagnetic steel sheet related to the tenth aspect, in a case where the surface of the grain-oriented electromagnetic steel sheet is divided into a first region in which the width W of a magnetic domain is equal to or greater than the limit value L and a second region in which the width W of the magnetic domain is less than the limit value L, the step of forming grooves or thermal deformations includes the formation of multiple grooves or thermal deformations in the first region based on the results of the analysis obtained by the step of analyzing the magnetic domain structure and, given that a fixed length that is the total of the ideal lengths of each of the multiple grooves or thermal deformations formed in the first region is C,a length that is the sum of the differences between the lengths and the, Petition 870250103202, dated 11 / 11 / 2025, page 16 / 103 / 37 ideal lengths of each of the multiple grooves or thermal deformations, grooves or thermal deformations in which the length of each is less than the width in a direction parallel to the direction of irradiation of the laser beam of the first region at the positions of the respective grooves or thermal deformations is D, a length that is the total of the differences between the lengths and the ideal lengths of each of the multiple grooves or thermal deformations, grooves or thermal deformations in which the length of each is greater than the width in a direction parallel to the direction of irradiation of the laser beam of the first region at the positions of the respective grooves or thermal deformations is E, and an admissible length ratio corresponding to the defined length C of the multiple grooves or thermal deformations is R, in the groove or thermal deformation formation step,Multiple grooves or thermal deformations that satisfy the following formula (1) are formed in the first region by controlling the laser beam based on the analysis results. (D+E) / C < R ...(1)

[0018] A twelfth aspect of the present description is a grain-oriented electromagnetic steel sheet, wherein the grain-oriented electromagnetic steel sheet is manufactured by the manufacturing method of a grain-oriented electromagnetic steel sheet of the tenth aspect, and, in the case where a surface of the grain-oriented electromagnetic steel sheet is divided into a first region in which the width W of a magnetic domain of the grain-oriented electromagnetic steel sheet is equal to or greater than the limit value L and a second region in which the width W of the magnetic domain of the grain-oriented electromagnetic steel sheet is less than the limit value L, the surface of the grain-oriented electromagnetic steel sheet includes several grooves or thermal deformations formed in the first region, and, given that a fixed length which is the sum of Petition 870250103202, dated 11 / 11 / 2025, page 17 / 103 / 37 ideal lengths of each of the various grooves or thermal deformations formed in the first region is C, a length that is the sum of the differences between the lengths and the ideal lengths of each of the various grooves or thermal deformations, grooves or thermal deformations in which the length of each of them is less than the width in a direction parallel to the direction of irradiation of the laser beam of the first region at the positions of the respective grooves or thermal deformations is D, a length that is the total of the differences between the lengths and the ideal lengths of each of the, among the multiple grooves or thermal deformations, grooves or thermal deformations in which the length of each of them is greater than the width in a direction parallel to the direction of irradiation of the laser beam of the first region at the positions of the respective grooves or thermal deformations is E,and a permitted length ratio corresponding to the defined length C of the multiple grooves or thermal deformations is R, the multiple grooves or thermal deformations that satisfy the following formula (1) are formed in the first region., (D+E) / C < R ...(1)

[0019] A thirteenth aspect of the present description is an iron core manufactured using the grain-oriented electromagnetic steel sheet related to the twelfth aspect. Advantageous Effects of the Invention

[0020] According to the present description, a magnetic domain structure analysis device, a magnetic domain structure analysis method, and a program are presented that can accurately measure the width of a magnetic domain compared to a case using the Fourier transform. Furthermore, according to the present description, a method for manufacturing a grain-oriented electromagnetic steel sheet is presented, which allows obtaining a steel sheet. Petition 870250103202, dated 11 / 11 / 2025, page 18 / 103 / 37 oriented grain electromagnetic in which the distortion of the magnetostriction waveform is small, while the iron loss is effectively reduced. Furthermore, according to the present description, an oriented grain electromagnetic steel sheet and an iron core are provided in which the distortion of the magnetostriction waveform is small, while the iron loss is effectively reduced. BRIEF DESCRIPTION OF THE DRAWING

[0021] Figure 1 is a block drawing illustrating the functional structures of a magnetic domain structure analysis device related to an embodiment of the present description.

[0022] Figure 2 is an explanatory drawing that illustrates the processing content of a magnetic domain width measurement section related to the embodiment of the present description.

[0023] Figure 3 is an explanatory drawing that illustrates the processing content of a magnetic domain orientation measurement section related to the embodiment of the present description.

[0024] Figure 4 is a drawing that illustrates an example of the width of a magnetic domain that has been corrected by a magnetic domain width correction section related to the embodiment of the present description.

[0025] Figure 5 is a block diagram illustrating the hardware structures of the magnetic domain structure analysis device related to the embodiment of the present description.

[0026] Figure 6 is a flowchart illustrating the flow of a magnetic domain structure analysis method related to an embodiment of the present description.

[0027] Figure 7 is a drawing that illustrates examples of a magnetic domain image, an analysis image of the magnetic domain structure related to an Example, and an analysis image of the magnetic domain structure related to a Comparative Example. Petition 870250103202, dated 11 / 11 / 2025, page 19 / 103 / 37

[0028] Figure 8 is a graph that illustrates an example of test results using an artificial image.

[0029] Figure 9 is a drawing that illustrates an example of a master core waveform.

[0030] Figure 10 is a drawing illustrating an example of a method for manufacturing a grain-oriented electromagnetic steel sheet, related to an embodiment of the present description.

[0031] Figure 11 is a drawing that compares a case in which a groove forming or thermal deformation step is performed based on the analysis results obtained by the magnetic domain structure analysis method relative to the embodiment of the present description, and a case in which a groove forming or thermal deformation step is performed based on the analysis results relative to the Comparative Example. DESCRIPTION OF THE MODALITIES

[0032] The modalities of the present description are described below.

[0033] Figure 1 is a block drawing illustrating the structures of a magnetic domain structure analysis device 10 related to an embodiment of the present description. The magnetic domain structure analysis device 10 is a device that acquires a magnetic domain image 50 showing the magnetic domain structure of a grain-oriented electromagnetic steel sheet 40 and measures the width and orientation of a magnetic domain based on the acquired magnetic domain image 50. The magnetic domain structure analysis device 10 has a section 12 for magnetic domain image acquisition and a section 14 for measurement.

[0034] Section 12 magnetic domain image acquisition is an imaging device that acquires the magnetic domain image 50 through the image of the grain-oriented electromagnetic steel plate 40. Petition 870250103202, dated 11 / 11 / 2025, page 20 / 103 / 37 Provided it is an imaging device capable of acquiring the magnetic domain image 50, the magnetic domain image acquisition section 12 can be any type of imaging device, such as, for example, a viewing device with magneto-optical elements, a scanning electron microscope, or an electromagnetic microscope. The magnetic domain image 50 is an image with a black and white striped pattern corresponding to the azimuths of the magnetic domains. What is called a magnetic domain here is a 180° magnetic domain. In the magnetic domain image 50, the width of the stripes corresponds to the width of the magnetic domains, and the direction in which the stripes extend corresponds to the orientation of the magnetic domains.The vertical direction of the magnetic domain image 50 is approximately parallel to the rolling direction of the grain-oriented electromagnetic steel sheet 40, and the horizontal direction of the magnetic domain image 50 is approximately orthogonal to the rolling direction. Hereafter, the rolling direction of the grain-oriented electromagnetic steel sheet 40 will be referred to as the Y direction, and the direction orthogonal to the rolling direction will be referred to as the X direction.

[0035] The measurement section 14 has a magnetic domain width measurement section 16, a magnetic domain orientation measurement section 18, and a magnetic domain width correction section 20. The measurement section 14 is performed, for example, by a computer equipped with a CPU (Central Processing Unit), a storage device, a memory, and the like.Because the CPU executes a program stored on the storage device using memory as a workspace, the CPU functions as the magnetic domain width measurement section 16, the magnetic domain orientation measurement section 18, and the magnetic domain width correction section 20.

[0036] The magnetic domain width measurement section 16 measures Petition 870250103202, dated 11 / 11 / 2025, page 21 / 103 14 / 37 the width of a magnetic domain of the grain-oriented electromagnetic steel sheet 40 based on the magnetic domain image 50 acquired by the magnetic domain image acquisition section 12. Figure 2 is an explanatory drawing illustrating the content of the magnetic domain width measurement procedures in section 16, relating to an embodiment of the present description. First, due to the magnetic domain width measurement section 16 defining parameters σ and u as predetermined values ​​in the formula of the one-dimensional Gabor filter complex expressed by the following formula (1), the magnetic domain width measurement section 16 defines a master core 22 which is the filter core that serves as a reference. Here, σ is a parameter that defines the dispersion of the filter core in the spatial direction, u is a parameter that defines the central frequency (central wavelength) of the filter core. In addition, x is the coordinate value in the X direction.The configuration method that sets the σ parameters to predetermined values ​​is described later. The reason the filter kernel is defined as a complex number is because, in the case where the magnetic domain image 50 is visualized as light and shadow in sinusoidal waveform, both the sinusoidal component and the cosine component at an arbitrary x-coordinate position must be detected. exp (— exp (2π lux') * · · (1)

[0037] Next, as shown by the following formula (2), the magnetic domain width measurement section 16 generates several filter cores 24 (n filter cores 24) of different spatial sizes, multiplying the master core 22 by A in the spatial direction corresponding to the direction orthogonal to the lamination direction of the grain-oriented electromagnetic steel sheet 40 and by 1 / A in the amplitude direction. Here, A is a number greater than 0, and this A is called the scale factor. The 24 plural filter cores that are structured in this way have pass filter characteristics. Petition 870250103202, dated 11 / 11 / 2025, page 22 / 103 15 / 37 band with respectively different center frequencies, but their peak gains are the same. That is, the output amplitudes, in the case where a sinusoidal wave corresponding to the filter's center frequency is applied as input, are the same. It is desirable that there be an arithmetic progression such that the As corresponding respectively to the filter's multiple cores 24 are in a uniform interval on the spatial axis. Aexpk (ÃTvJ exp(2mux / Aj · · ( 2 )

[0038] Next, the magnetic domain width measurement section 16 generates several complex two-dimensional images 26 (n complex two-dimensional images 26) by directing the respective filter cores 24, which have a scattering function in the X direction, in the horizontal direction of the magnetic domain image 50 (the direction corresponding to the direction orthogonal to the lamination direction of the grain-oriented electromagnetic steel sheet 40, the direction corresponding to the direction orthogonal to the extension direction of the magnetic domain) and applying the respective filter cores 24 to the brightness values ​​of the magnetic domain image 50. In this case, the magnetic domain width measurement section 16 applies the respective filter cores 24 to all pixels of the magnetic domain image 50. The complex two-dimensional images 26 are images of the same size as the magnetic domain image 50.

[0039] Next, the magnetic domain width measurement section 16 calculates the absolute value B of the filter output for each pixel of each of the two-dimensional complex images 26 using the following formula (3). Here, Re represents the real part of the two-dimensional complex image 26, and Im represents the imaginary part of the two-dimensional complex image 26.

[0040] Filter core 24, which has a specific center frequency, is applied to magnetic domain image 50, which exhibits black / white brightness values ​​that vary according to the domain. Petition 870250103202, dated 11 / 11 / 2025, page 23 / 103 16 / 37 magnetic. Therefore, the central frequency of the filter core 24, whose absolute value B is the maximum, is closest to the frequency of the striped pattern formed by the magnetic domains in the magnetic domain image 50. That is, the central frequency of the bandpass filter expressed by formula (2) is (u / A) (unit: 1 / pixel), and the wavelength is (A / u) (unit: pixel). In the magnetic domain image 50, given that a pair of a white portion and a black portion is a wavelength, in the case where the widths of the white portion and the black portion are equal, the absolute value B of the filter core 24 becomes maximum when the width of the magnetic domain is A / (2u). B = + Im2· · · ( 3 )

[0041] Next, section 16 of the magnetic domain width measurement generates, per filter core 24, an absolute value image 28 that shows the absolute value B of each pixel. Because of this, plural absolute value images 28 are obtained (n absolute value images 28). The absolute value images 28 are images of the same size as the magnetic domain image 50. Then, comparing the plural absolute value images 28, section 16 of the magnetic domain width measurement specifies the filter core 24 that corresponds to the absolute value image 28 whose absolute value B is the largest, per pixel (i.e., per same coordinate). Therefore, for each pixel, the filter core 24 whose spatial size is most suitable for the width of the band is specified from among the various filter cores 24.

[0042] Next, section 16 of the magnetic domain width measurement generates a 30 scale factor distribution image, showing the distribution of the A scale factors corresponding to the specified 24 filter core per pixel. Figure 2 illustrates an example of the 30 scale factor distribution image showing the distribution of the A scale factors of the 24 filter cores whose absolute B values ​​are maximum (the 30 scale factor distribution image is divided into a sectional image by A scale factor value, due to the A scale factors being Petition 870250103202, dated 11 / 11 / 2025, page 24 / 103 / 37 different).

[0043] Next, for each pixel of the scale factor 30 distribution image, magnetic domain width measurement section 16 derives the magnetic domain width W. Specifically, magnetic domain width measurement section 16 derives the magnetic domain width W by the following formula (4). According to the above procedures, magnetic domain width measurement section 16 measures the magnetic domain width based on the magnetic domain image acquired by magnetic domain image acquisition section 12. W = A / (2u) · · · ( 4 )

[0044] Next, an example of the configuration method that defines parameters σeu of the master core 22 to predetermined values ​​is described. First, based on the width of the magnetic domain to be measured, the magnification at the time of image acquisition of the magnetic domain, and other factors, the range (whose unit is the number of pixels) of the band width is derived, which corresponds to the width of the magnetic domain to be measured. Then, parameters σeu are defined so that the filter core 24, in which the absolute value B is taken to be the largest for the range derived from the band width, is included. For example, in the master core 22 of a case where the number of pixels corresponding to the band width is 10 pixels, the central wavelength is 20 pixels and, consequently, the central frequency is 1 / 20 (unit: 1 / pixels), and therefore u = 1 / 20.

[0045] Furthermore, since the master core must have a length greater than or equal to the shortest wavelength, it is preferable that σ, with respect to au = 1 / 20, be 20 pixels or more, and the master core is expressed by the following formula (5), for example. Furthermore, the master core expressed by formula (5) is a waveform as illustrated in Fig. 9. The master core 22 is generated by the magnetic domain width measurement section 16 by Petition 870250103202, dated 11 / 11 / 2025, page 25 / 103 18 / 37 procedures described above. . Z , 2 (ιπχ\ , f X \ . / Γ- \exp\Nõ)exp(\2õ) ' * *

[0046] The magnetic domain orientation measurement section 18 measures the orientation of a magnetic domain of the grain-oriented electromagnetic steel sheet 40 based on the magnetic domain image 50 acquired by the magnetic domain image acquisition section 12. Figure 3 is an explanatory drawing illustrating the content of the magnetic domain orientation measurement section 18 procedures, relating to an embodiment of the present description. First, the magnetic domain orientation measurement section 18 changes the parameter p in the two-dimensional Gaussian function expressed by the following formula (6), and generates multiple two-dimensional Gaussian functions that have the same volumes and different spatial sizes. Here, x is the coordinate value in the X direction and y is the coordinate value in the Y direction.The method for setting the parameter p in this case may be the same as or different from the setting method described above, σ in the magnetic domain width measurement section 16. Note that the maximum value of the parameter p is preferably greater than the maximum width of the stripes. Figure 3 illustrates two two-dimensional Gaussian functions as an example of the various two-dimensional Gaussian functions. -exv(-x2+y\ · · · (6 2ττρ2 Pk2pZ) k

[0047] Next, by differentiating the respective two-dimensional Gaussian functions in the X and Y directions, the magnetic domain orientation measurement section 18 generates a differentiated filter core in the X direction 32A and a differentiated filter core in the Y direction 32B. Therefore, the differentiated filter core in the X direction 32A and the differentiated filter core in the Y direction 32B are obtained for each of the two-dimensional Gaussian functions that have different spatial sizes. In Figure 3, two sets of the differentiated filter core in the X direction 32A and the filter core of Petition 870250103202, dated 11 / 11 / 2025, page 26 / 103 / 37 differentiated filter in the Y direction 32B are illustrated as an example of multiple sets of differentiated filter cores.

[0048] Next, the magnetic domain orientation measurement section 18 generates differentiated images in the X direction 34A, in which the respective differentiated filter cores in the X direction 32A were applied to the magnetic domain image 50, and differentiated images in the Y direction 34B, in which the respective differentiated filter cores in the Y direction 32B were applied to the magnetic domain image 50. In this case, the magnetic domain orientation measurement section 18 applies the respective differentiated filter cores in the X direction 32A and the respective differentiated filter cores in the Y direction 32B to all pixels of the magnetic domain image 50. In Fig. 3, two sets of differentiated images in the X direction 34A and differentiated images in the Y direction 34B are illustrated as an example of the various sets of differentiated images.

[0049] Next, using the following formula (7), the magnetic domain orientation measurement section 18 obtains the gradient intensity G(p) for each pixel of each set of the differentiated image in the X direction 34A and differentiated image in the Y direction 34B. Here, Rx(p) represents the value of each pixel of the differentiated image in the X direction 34A, and Ry(p) represents the value of each pixel of the differentiated image in the Y direction 34B. Rx(p) corresponds to the output of the differentiated filter core in the X direction 32A corresponding to each parameter. p, and Ry(p) corresponds to the output of the differentiated filter core in the Y direction 32B corresponding to each parameter. p. Furthermore, the gradient intensity G(p) corresponds to the square root of the sum of the squares of the respective outputs of the differentiated filter core in the X direction 32A and the differentiated filter core in the Y direction 32B.In a case where the dispersion of the Gaussian function of formula (6) is the size of a pair of black / white stripes, that is, it is about twice the width of the magnetic domain, the gradient intensity of the. Petition 870250103202, dated 11 / 11 / 2025, p. 27 / 103 20 / 37 formula (7) is the largest. Therefore, [Rx(p), Ry(p)] which corresponds to p where the gradient intensity G(p) is the largest vector in the direction orthogonal to the stripes. For example, in a case where the stripes are parallel to the lamination direction, Ry(p) is zero, and only the value of Rx(p) exists. G(p) = 7( / ?x(p)p + (fiy(p))2· · · ( 7 )

[0050] Next, section 18 of measuring the magnetic domain orientation generates a gradient intensity image 36 that shows the gradient intensity per pixel, for each set of differentiated filter cores in the X direction 32A and differentiated filter cores in the Y direction 32B. In this way, multiple gradient intensity images 36 are obtained. In Figure 3, two of the gradient intensity images 36 are illustrated as an example of the multiple gradient intensity images 36.

[0051] Next, comparing the plural gradient intensity images 36, the magnetic domain orientation measurement section 18 specifies p, which corresponds to the gradient intensity image 36 whose gradient intensity is the highest, for each pixel (i.e., for each equal coordinate).

[0052] Then, based on the values ​​of the respective pixels of the differentiated image in the X direction 34A and the differentiated image in the Y direction 34B specified, the magnetic domain orientation measurement section 18 calculates, per pixel, the angle Θ of the magnetic domain orientation by the following formula (8). The angle Θ of the magnetic domain orientation corresponds to the smaller angle of the angles formed by the direction orthogonal to the lamination direction and the magnetic domain orientation. According to the above procedures, the magnetic domain orientation measurement section 18 measures the magnetic domain orientation based on the magnetic domain image acquired by the magnetic domain image acquisition section 12. Θ — atan^Ry(p) / Rx(p)') + π / 2 · · · ( 8 ) Petition 870250103202, dated 11 / 11 / 2025, page 28 / 103 / 37

[0053] The magnetic domain width correction section 20 corrects the magnetic domain width W that was measured by the magnetic domain width measurement section 16, based on the magnetic domain orientation that was measured by the magnetic domain orientation measurement section 18. As a result, the corrected magnetic domain width W' is obtained. Figure 4 is a drawing illustrating an example of the magnetic domain width W' that was corrected by the magnetic domain width correction section 20, relative to an embodiment of the present description. As illustrated in Fig. 4, the magnetic domain width W, measured by the magnetic domain width measurement section 16, is the width along the direction (i.e., the horizontal direction of the magnetic domain image 50) orthogonal to the lamination direction.Thus, in a case where the orientation of the magnetic domain is not parallel to the lamination direction, a width greater than the width in the direction orthogonal to the orientation of the magnetic domain is measured by the magnetic domain width measurement section 16, and an error arises between the magnetic domain width measured by the magnetic domain width measurement section 16 and the width in the direction orthogonal to the orientation of the magnetic domain (i.e., the magnetic domain width that one actually wants to obtain).

[0054] Here, the magnetic domain width correction section 20 calculates the width W' in the direction orthogonal to the magnetic domain orientation by the following formula (9) and based on the magnetic domain width W measured by the magnetic domain width measurement section 16 and the magnetic domain orientation angle θ measured by the magnetic domain orientation measurement section 18. According to the above procedures, the magnetic domain width correction section 20 corrects the magnetic domain width W measured by the magnetic domain width measurement section 16, based on the magnetic domain orientation measured by the magnetic domain orientation measurement section 18. Petition 870250103202, dated 11 / 11 / 2025, page 29 / 103 22 / 37 w' = W x Sind · · · ( 9 )

[0055] Figure 5 is a block diagram illustrating the hardware structures of the magnetic domain structure analysis device 10, related to the embodiment of the present description. As illustrated in Fig. 5, the magnetic domain structure analysis device 10 is structured by a computer. The magnetic domain structure analysis device 10 has, as hardware, a processor 100, a memory 102 and a storage 104. The processor 100, the memory 102 and the storage 104 are connected in such a way that they can communicate with each other through the bus 106.

[0056] Processor 100 has a CPU (Central Processing Unit) or something similar. Memory 102 has a ROM (Read Only Memory) and a RAM (Random Access Memory) or something similar. ROM stores various programs and various data. RAM temporarily stores programs or data as a workspace. Storage 104 is structured by an HDD (Hard Disk Drive) or an SSD (Solid State Drive) or similar, and stores various programs, including the operating system, and various data.

[0057] A program 108 for analyzing the structure of a magnetic domain is stored in storage 104. Processor 100 reads program 108 and executes program 108 using RAM as workspace. The magnetic domain width measurement section 16, the magnetic domain orientation measurement section 18, and the magnetic domain width correction section 20 described above (see Fig. 1) are performed by processor 100 executing program 108.

[0058] Note that processor 100 may include a dedicated-use processor, such as a GPU (Graphics Processing Unit), an ASIC (Application-Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or similar. Furthermore, processor 100 Petition 870250103202, dated 11 / 11 / 2025, page 30 / 103 / 37 can be structured by a single processor or by multiple processors. The program 108 can be stored in a non-transient and computer-readable storage medium 110.

[0059] Next, a method for analyzing the structure of magnetic domains related to an embodiment of the present description is described.

[0060] Figure 6 is a flowchart illustrating the flow of the magnetic domain structure analysis method related to the embodiment of the present description. The magnetic domain structure analysis method is performed by the magnetic domain structure analysis device 10 described above. When initiating the magnetic domain structure analysis method, first, in step S10, the magnetic domain image acquisition section 12 acquires the image of the magnetic domain 50 through the image of the grain-oriented electromagnetic steel plate 40. Then, the magnetic domain structure analysis device 10 acquires the image of the magnetic domain 50 acquired by the magnetic domain image acquisition section 12. Step S10 is an example of the magnetic domain image acquisition step.

[0061] Next, in step S12, the magnetic domain width measurement section 16 measures the magnetic domain width W based on the magnetic domain image 50 acquired by the magnetic domain image acquisition section 12. Step S12 is an example of the magnetic domain width measurement step.

[0062] Next, in step S14, the magnetic domain orientation measurement section 18 measures the magnetic domain orientation based on the magnetic domain image 50 acquired by the magnetic domain image acquisition section 12. Step S14 is an example of the magnetic domain orientation measurement step.

[0063] Next, in step S16, the magnetic domain width correction section 20 corrects the magnetic domain width W that was Petition 870250103202, dated 11 / 11 / 2025, page 31 / 103 / 37 measured by the magnetic domain width measurement section 16, based on the magnetic domain orientation that was measured by the magnetic domain orientation measurement section 18. As a result, the corrected width W' of the magnetic domain is obtained. Step S16 is an example of the magnetic domain width correction step. The magnetic domain structure analysis method then concludes.

[0064] The effects of the modality of the present description are described below.

[0065] As described above, in the magnetic domain structure analysis device 10, the magnetic domain width measurement section 16 generates multiple filter cores 24 of different spatial sizes by multiplying a complex one-dimensional Gabor filter by A in the spatial direction corresponding to the direction orthogonal to the lamination direction of the grain-oriented electromagnetic steel sheet 40, and by 1 / A in the amplitude direction. Then, section 16, which measures the magnetic domain width, calculates the absolute value B of the filter output per filter core 24 by applying the multiple filter cores 24 respectively to the magnetic domain image 50. Then, the magnetic domain width measurement section 16 derives the width W of a magnetic domain of the grain-oriented electromagnetic steel sheet 40 based on the spatial size of the filter whose absolute value B is the largest among the multiple filter cores 24.Thus, since the width W of the magnetic domain can be measured without using the Fourier transform, all the problems associated with measuring the width W of a magnetic domain using the Fourier transform can be avoided. Because of this, the width W of a magnetic domain can be measured with greater precision compared to the case where the width W of a magnetic domain is measured using the Fourier transform.

[0066] In addition, the domain orientation measurement section Petition 870250103202, dated 11 / 11 / 2025, page 32 / 103 / 37 magnetic 18 generates plural sets of differentiated filter core in the X direction 32A and differentiated filter core in the Y direction 32B, differentiating two-dimensional Gaussian functions, which have different spatial sizes, in the X direction that corresponds to the direction orthogonal to the lamination direction of the grain-oriented electromagnetic steel sheet 40 and in the Y direction that corresponds to the lamination direction, by two-dimensional Gaussian function. Next, applying respectively to the magnetic domain image 50 the plural sets of the differentiated filter core in the X direction 32A and the differentiated filter core in the Y direction 32B, the magnetic domain orientation measurement section 18 derives the square roots of the sums of the squares of the respective filter outputs of the differentiated filter cores in the X direction 32A and the differentiated filter cores in the Y direction 32B of the plural sets.Next, the magnetic domain orientation measurement section 18 derives the orientation of a magnetic domain from the grain-oriented electromagnetic steel sheet 40 based on the respective outputs of the differentiated filter core assembly in the X direction 32A and the differentiated filter core assembly in the Y direction 32B that has the largest square root of the sum of squares among the plural assemblies of the differentiated filter core in the X direction 32A and the differentiated filter core assembly in the Y direction 32B. Thus, since the orientation of a magnetic domain can be measured without using the Fourier transform, all the problems associated with measuring the orientation of a magnetic domain using the Fourier transform can be avoided. Because of this, the orientation of a magnetic domain can be measured with precision, compared to the case where the orientation of a magnetic domain is measured using the Fourier transform.

[0067] In addition, the magnetic domain width correction section 20 corrects the magnetic domain width W that was measured by the magnetic domain width measurement section 16, based on Petition 870250103202, dated 11 / 11 / 2025, page 33 / 103 / 37 orientation of the magnetic domain that was measured by the magnetic domain orientation measurement section 18. Specifically, the magnetic domain width correction section 20 derives the width W' in the direction orthogonal to the magnetic domain orientation, based on the magnetic domain width W measured by the magnetic domain width measurement section 16 and the magnetic domain orientation angle θ measured by the magnetic domain orientation measurement section 18. Because of this, compared to a case where the magnetic domain orientation is not parallel to the lamination direction, and the magnetic domain width W measured by the magnetic domain width measurement section 16 is treated as such, it is possible to obtain a highly accurate magnetic domain width (i.e., the magnetic domain width that one actually wants to obtain).

[0068] Moreover, in the present implementation, a complex one-dimensional Gabor filter is used to measure the width of the magnetic domain. However, instead of a complex one-dimensional Gabor filter, the use of a two-dimensional Gabor filter that can measure both the width and orientation of a magnetic domain is being considered. However, since the orientation of the magnetic domain is generally substantially parallel to the lamination direction, there is no need to explicitly use a two-dimensional Gabor filter to determine the width and orientation of a magnetic domain. Thus, by using a complex one-dimensional Gabor filter, as in the present implementation, the processing load of processor 100 can be reduced compared to the use case of a two-dimensional Gabor filter.

[0069] An example is described below.

[0070] Figure 7 is a drawing that illustrates examples of a magnetic domain image, an analysis image of the magnetic domain structure related to an Example, and an analysis image of the magnetic domain structure related to a Comparative Example. The image of Petition 870250103202, dated 11 / 11 / 2025, page 34 / 103 / 37. The magnetic domain is an image acquired by magnetic domain image acquisition section 12. The magnetic domain structure analysis image related to the Example is an image generated from the magnetic domain image using magnetic domain structure analysis device 10 related to the present implementation, and is an image that shows, pixel by pixel, the magnetic domain width corrected by magnetic domain width correction section 20. The magnetic domain structure analysis image related to the Comparative Example is an image generated from the magnetic domain image using the Fourier transform, and shows, pixel by pixel, the magnetic domain width derived by the Fourier transform.In the magnetic domain structure analysis image for Example and in the magnetic domain structure analysis image for Comparative Example, the brightness / darkness of the pixels shows the width of the magnetic domains.

[0071] In the magnetic domain structure analysis image for Example, the magnetic domain widths obtained correspond to the widths of the magnetic domain image bands. In contrast, in the magnetic domain structure analysis image for Comparative Example, in regions where the band widths are wide, the magnetic domain widths obtained do not correspond to the band widths. It is presumed that the cause of this is insufficient detection resolution in regions where the band width is large.

[0072] Figure 8 is a graph illustrating an example of test results using an artificial image. The artificial image is an image in which the width of the black / white bands varies in a straight line. The line on the graph showing the actual values ​​indicates the width of the bands in the artificial image. The graph showing the Example presents the results of measuring the width of the bands in the artificial image using the magnetic domain structure analysis device relative to the present implementation. Petition 870250103202, dated 11 / 11 / 2025, page 35 / 103 / 37 The line in the graph showing the Comparative Example presents the results of measuring the width of the artificial image bands using the Fourier transform.

[0073] In the example, measurement results corresponding to the actual values ​​are obtained. In contrast, in the Comparative Example, measurement results corresponding to the actual values ​​are not obtained in a partial range of bandwidths (for example, the range where the bandwidths vary from 32 μm to 64 μm). It is assumed that the reason for this is that, since the width of the Fourier transform window (i.e., the size of the Fourier transform) is not an integer multiple of the bandwidth, the peaks of the spectrum are scattered and it is not possible to determine precise peak values.

[0074] The following describes a method for manufacturing a grain-oriented electromagnetic steel sheet, related to one embodiment of the present invention.

[0075] Figure 10 is a drawing illustrating an example of the manufacturing method for a grain-oriented electromagnetic steel sheet, relating to the present embodiment. The manufacturing method for a grain-oriented electromagnetic steel sheet, related to the present embodiment, has, as an example, a casting step, a hot rolling step, an annealing step, a cold rolling step, a decarburizing annealing step, an annealing separator coating step, a finishing annealing step, an insulating film formation step, a magnetic domain structure analysis step, a groove formation or thermal deformation step, and a second insulating film formation step.

[0076] The casting stage is a stage in the production process of a plate using a continuous casting method. The hot rolling stage consists of performing hot rolling on a plate. Petition 870250103202, dated 11 / 11 / 2025, pp. 36 / 103 / 37, which was heated to a predetermined temperature (e.g., 1100°C or 1400°C), thus obtaining a hot-rolled steel sheet. The annealing stage consists of annealing the hot-rolled steel sheet instantly or for a short period of time, thus obtaining an annealed steel sheet. The cold rolling stage consists of obtaining a cold-rolled steel sheet, either by cold rolling the annealed steel sheet once, or by multiple cold rollings (e.g., two or more times) through intermediate annealing. The decarburization annealing step consists of performing decarburization annealing on cold-rolled steel sheets, obtaining an annealed steel sheet in which primary recrystallization has already occurred.

[0077] The coating step with an annealing separator agent consists of applying an annealing separator agent to the decarburized annealed steel sheet. The finishing annealing step consists of performing finishing annealing on the decarburized annealed steel sheet, onto which the annealing separator agent has been applied, causing secondary recrystallization and obtaining a finished annealed steel sheet. Here, finished annealed steel sheet means the steel sheet on which finishing annealing has been performed on the decarburized annealed steel sheet, on which the annealing separator agent has been applied and on which secondary recrystallization has occurred. The insulating film formation step consists of applying and curing a coating solution on the surface of the annealed steel sheet, thus forming an insulating film on its surface. The grain-oriented electromagnetic steel sheet 40 illustrated in Fig.1 corresponds to the annealed steel finishing sheet.

[0078] The magnetic domain structure analysis step consists of, using the magnetic domain structure analysis method Petition 870250103202, dated 11 / 11 / 2025, page 37 / 103 / 37 related to the present modality described above, perform the analysis of the magnetic domain structure which includes the determination of the width of a magnetic domain of the grain-oriented electromagnetic steel sheet (i.e., the width of a magnetic domain measured by the magnetic domain width measurement section 16 or the width of a magnetic domain corrected by the magnetic domain width correction section 20).

[0079] The groove or thermal deformation stage is a stage of, based on the results of the analysis obtained in the magnetic domain structure analysis stage, irradiating a laser beam onto the surface of the grain-oriented electromagnetic steel sheet, which is being transported in the transport direction, thus forming multiple grooves or thermal deformations that extend in a direction that intersects the transport direction, at regular intervals. Note that the transport direction substantially coincides with the rolling direction in the hot and cold rolling stages described above. As the orientations of the magnetic domains are substantially parallel to the rolling direction, the grooves or thermal deformations are formed so as to extend in a direction that intersects the orientations of the magnetic domains.

[0080] The second stage of insulating film formation consists of coating and heating a coating solution on the surface of the grain-oriented electromagnetic steel sheet, in which multiple grooves or thermal deformations have been formed, thus forming an insulating film on the surface of the grain-oriented electromagnetic steel sheet. A grain-oriented electromagnetic steel sheet is manufactured by the processes described above.

[0081] The present inventors initially studied, in the magnetic domain structure analysis stage, the acquisition of multiple partial Fourier images, performing the Fourier transform on multiple partial images included in a magnetic domain image, using Petition 870250103202, dated 11 / 11 / 2025, page 38 / 103 / 37 the Fourier transform (two-dimensional single-section Fourier transform), and deriving the width and orientation of a magnetic domain based on the peak point value of each partial Fourier image.

[0082] However, the inventors found that the following problems exist when using a Fourier transform to derive the width of a magnetic domain based on a magnetic domain image. Namely, the present inventors found that, in a case where the width of the Fourier transform window (i.e., the size of the Fourier transform) is not an integer multiple of the width of the magnetic domain, the peaks of the spectrum become scattered and a precise peak value cannot be determined. Furthermore, the present inventors found that, in the Fourier transform, since the spectra are in a uniform range on the frequency axis, but in a non-uniform range when viewed by wavelength, the detection resolution of the width of a magnetic domain decreases, especially in locations where the width of the magnetic domain is large.Specifically, the present inventors have verified that locations where the width W of the magnetic domain is greater than a limiting value L must be determined, but for this, the Fourier transform window must be defined in a moving section that is at least 2L. Furthermore, the present inventors have verified that an error (intermediate value) of ± L / 2 arises from the limit of the theoretically real value of the Fourier transform. Note that the limiting value L is 500 μm.

[0083] Figure 11 is a drawing comparing a case where the groove forming or thermal deformation step is performed based on the results of the analysis relating to the present embodiment, and a case where the groove forming or thermal deformation step is performed based on the results of the analysis relating to the Comparative Example. Fig. 11(A) illustrates a case where the groove forming or thermal deformation step is performed based on the analysis results obtained by the method ofPetition 870250103202, dated 11 / 11 / 2025, page 39 / 103 / 37 analysis of the magnetic domain structure related to the present implementation in the magnetic domain structure analysis step. As a comparative example, Fig. 11(B) illustrates a case where the groove formation or thermal deformation step is performed based on the analysis results obtained using the Fourier transform in the magnetic domain structure analysis step. In a case where the surface of the grain-oriented electromagnetic steel sheet is divided into a first region A1, in which the width W of the magnetic domain is equal to or greater than the limit value L, and a second region A2, in which the width W of the magnetic domain is less than the limit value L, the groove formation or thermal deformation step includes the formation of multiple grooves or thermal deformations 200 in the first region A1, based on the analysis results.Note that, in the present configuration, a laser beam is irradiated from one end to the other in the direction of the width of the sheet in the first region A1 (the 90°C direction relative to the transport direction or the lamination direction), continuously, without interruption, so as to extend in a single direction.

[0084] According to the method of analysis of the magnetic domain structure relative to the present modality, it is possible to identify positions irradiated by the laser beam in ways that are close to the laser beam irradiation distribution determined from real values. However, in the case of the Fourier transform, grooves or thermal deformations resulting from incorrect laser beam impacts, or grooves or thermal deformations resulting from excessive laser beam impacts, are formed. The grooves or thermal deformations that represent misalignment faults are grooves or thermal deformations in which the length of each of them is less than the width, in the direction parallel to the laser beam irradiation direction, of the first region A1 at the positions of the respective grooves or thermal deformations. The grooves or deformations Petition 870250103202, dated 11 / 11 / 2025, page 40 / 103 / 37 thermal impacts that are excessive laser beam impacts are grooves or thermal deformations in which the length of each is greater than the width, in the direction parallel to the direction of irradiation of the laser beam, of the first region A1 in the positions of the respective grooves or thermal deformations.

[0085] When the groove formation or thermal deformation step is performed based on the results of the analysis relating to the present embodiment, the following grain-oriented electromagnetic steel sheet can be manufactured. That is, a grain-oriented electromagnetic steel sheet, in which several grooves or thermal deformations 200 are formed that satisfy the following formula (10) in the first region A1, can be manufactured by controlling the laser beam in the groove formation or thermal deformation step based on the results of the analysis relating to the present embodiment, given that a fixed length, which is the total of the ideal lengths of each of the several grooves or thermal deformations 200 formed in the first region A1, is C, and that the length, which is the total of the differences between the lengths and the ideal lengths of each of the several grooves or thermal deformations 200,The length of the slots or thermal deformations where the length of each is less than the width in a direction parallel to the direction of radiation of the laser beam from the first region A1 at the positions of the respective slots or thermal deformations is D, and the length, which is the total of the differences between the lengths and the ideal lengths of each of the various slots or thermal deformations 200, of the slots or thermal deformations where the length of each is greater than the width in a direction parallel to the direction of radiation of the laser beam from the first region A1 at the positions of the respective slots or thermal deformations is E, and the allowed ratio corresponding to the defined length C of the multiple slots or thermal deformations 200 is R. Note that the length C described, Petition 870250103202, dated 11 / 11 / 2025, p. 41 / 103 / 37 above is a value obtained by multiplying the number of laser beams irradiated in the first region A1 (the total number of slots or thermal deformations used in the derivation of D and E) by the width in the direction parallel to the irradiation direction of the laser beam of the first region A1.

[0086] The smaller the value on the left-hand side of formula (10), the lower the rate of failures and excessive impacts of the laser beam, and it can be said that the laser beam is irradiated more precisely in a selected portion. It is sufficient that R be 0.2, for example, and R be preferably 0.1 and more preferably 0.05. (D+E) / C < R ...(10)

[0087] Note that the grain-oriented electromagnetic steel sheet, manufactured by the manufacturing method relating to the present embodiment, can be specified by the following technique. That is, the positions where the laser beam was irradiated are identified visually or by observing the magnetic domain of the grain-oriented electromagnetic steel sheet, which is the target. Then, a stress-relief annealing (SRA) is performed on the grain-oriented electromagnetic steel sheet, removing the thermal stresses caused by the laser beam irradiation. Then, demagnetization is performed in a predetermined direction.Next, observing the domain structure using a magnetic field imaging system and visualizing the magnetic domain image with the naked eye, the grain-oriented electromagnetic steel sheet is divided into the first region A1, which is the portion where the width of the magnetic domain (the width in the direction orthogonal to the walls of the magnetic domain) is equal to or greater than the limit value L, and the second region A2, where the width is less than the limit value L. Then, it is verified whether formula (10) is satisfied. The grain-oriented electromagnetic steel sheet, manufactured by the manufacturing method relating to the present embodiment, can be specified by such technique.

[0088] As described in detail above, according to Petition 870250103202, dated 11 / 11 / 2025, page 42 / 103 / 37 manufacturing method of a grain-oriented electromagnetic steel sheet, relating to the present embodiment, in comparison with the Comparative Example, a laser beam can be irradiated with greater precision in selected portions and, therefore, a grain-oriented electromagnetic steel sheet, in which the distortion of the magnetostriction waveform is small, while the loss in iron is effectively reduced, can be obtained.

[0089] The following describes an example of a method for manufacturing a grain-oriented electromagnetic steel sheet, related to the present embodiment.

[0090] A grain-oriented electromagnetic steel sheet, with sample dimensions of 100 mm x 100 mm, was collected from the iron core of a transformer or coil in a format such that the mechanical stress of a wire cutter or similar was not included in it.

[0091] The laser beam irradiation positions were determined by visually inspecting the surface of the grain-oriented electromagnetic steel plate. In cases where visual assessment was not possible, the surface of the grain-oriented electromagnetic steel plate was confirmed using a magnetic field imaging system. In cases where a clear conclusion could not be reached even with a magnetic field imaging system, the surface of the grain-oriented electromagnetic steel plate was confirmed by applying a magnetic field orthogonal to the plate surface.

[0092] Stress relief annealing (SRA) was performed by annealing in which the grain-oriented electromagnetic steel sheet was 250 held at 850°C and cooled to 200°C at an average cooling rate of 20°C / h, and then cooled to 50°C at an average cooling rate of 100°C / h.

[0093] With regard to the moment of demagnetization and the observation of the magnetic domain structure, an image of the magnetic domain was Petition 870250103202, dated 11 / 11 / 2025, page 43 / 103 / 37 captured 30 seconds after the start of magnetic flux density attenuation, according to formula (11). B = 1.9e-0.3tcos0.70nt ...(11)

[0094] Here, B is the magnetic flux density (T) and et is the time (s).

[0095] In the present example, a grain-oriented electromagnetic steel sheet, in which multiple grooves or thermal deformations 200 satisfying formula (10) above were formed in the first region A1, could be manufactured.

[0096] Although the modalities of the present description have been described above, the present description is not limited to the above and may, of course, be implemented and modified in various other ways, within a scope that does not depart from its essence.

[0097] All publications, patent applications and technical standards mentioned in this specification are incorporated by reference to the same extent as if each individual publication, patent application or technical standard were specifically and individually indicated for incorporation by reference. In addition, the description of Japanese patent application No. 2023-062398, filed on April 6, 2023, is incorporated in its entirety by reference into this description. Explanation of reference numerals

[0098] 10 Magnetic Domain Structure Analysis Device Magnetic Domain Image Acquisition Section Measurement Section Magnetic Domain Width Measurement Section Magnetic Domain Orientation Measurement Section Magnetic Domain Width Correction Section Master Core Filter Core Complex Two-Dimensional Image Petition 870250103202, dated 11 / 11 / 2025, page 44 / 103 / 37 absolute value image scaling factor distribution image 32A differentiated filter core in the X direction 32B differentiated filter core in the Y direction 34A differentiated image in the X direction 34B differentiated image in the Y direction gradient intensity image grain-oriented electromagnetic steel plate magnetic domain image 100 processor 102 memory 104 storage 106 bus 108 program 110 non-transient storage medium 200 groove or thermal deformation

Claims

1. Magnetic domain structure analysis device, characterized in that it comprises: a magnetic domain image acquisition section that acquires a magnetic domain image by imaging a grain-oriented electromagnetic steel plate;and a magnetic domain width measurement section measuring the width of a magnetic domain of grain-oriented electromagnetic steel sheet based on the magnetic domain image, wherein the magnetic domain width measurement section generates a plurality of filter cores of different spatial sizes by multiplying a complex one-dimensional Gabor filter by A in a spatial direction corresponding to a direction orthogonal to a lamination direction of the grain-oriented electromagnetic steel sheet, and by 1 / A in an amplitude direction, applies the plurality of filter cores respectively to the magnetic domain image and calculates an absolute value of the filter output per filter core, and derives the magnetic domain width of the grain-oriented electromagnetic steel sheet based on the spatial size of the filter core whose absolute value is the largest among the plurality of filter cores.

2. Magnetic domain structure analysis device according to claim 1, characterized in that it comprises a magnetic domain orientation measurement section that measures the orientation of a magnetic domain of grain-oriented electromagnetic steel sheet based on the magnetic domain image. wherein the magnetic domain orientation measurement section generates a plurality of filter core sets. Petition 870250103202, 11 / 11 / 2025, p.46 / 103 2 / 9 differentiated differentiating two-dimensional Gaussian functions of different spatial sizes in an X direction that corresponds to the direction orthogonal to the lamination direction of the grain-oriented electromagnetic steel sheet and in a Y direction that corresponds to the lamination direction of the grain-oriented electromagnetic steel sheet, for each of the two-dimensional Gaussian functions, applies the plurality of sets of differentiated filter cores respectively to the image of the magnetic domain and calculates square roots of the sums of squares of the respective filter outputs of the differentiated filter cores of the plurality of sets, and derives the orientation of the magnetic domain of the grain-oriented electromagnetic steel sheet based on the respective filter outputs of the differentiated filter cores of the set that has the largest square root of the sum of squares, among the plurality of sets of differentiated filter cores.

3. Magnetic domain structure analysis device according to claim 2, characterized in that it comprises a magnetic domain width correction section that corrects the magnetic domain width of the grain-oriented electromagnetic steel sheet that was measured by the magnetic domain width measurement section, based on the magnetic domain orientation of the grain-oriented electromagnetic steel sheet that was measured by the magnetic domain orientation measurement section.

4. Magnetic domain structure analysis method, characterized in that it comprises: a magnetic domain image acquisition step to acquire a magnetic domain image by means of image formation of a grain-oriented electromagnetic steel plate; and a magnetic domain width measurement step for Petition 870250103202, dated 11 / 11 / 2025, page 1.47 / 103 3 / 9 measure the width of a magnetic domain based on the magnetic domain image, wherein the magnetic domain width measurement step generates a plurality of filter cores of different spatial sizes by multiplying a complex one-dimensional Gabor filter by A in a spatial direction corresponding to a direction orthogonal to a lamination direction of the grain-oriented electromagnetic steel sheet, and by 1 / A in an amplitude direction, applies the plurality of filter cores respectively to the magnetic domain image and calculates an absolute value of the filter output per filter core, and derives the magnetic domain width of the grain-oriented electromagnetic steel sheet based on the spatial size of the filter core whose absolute value is the largest among the plurality of filter cores.

5. Magnetic domain structure analysis method according to claim 4, characterized in that it comprises a magnetic domain orientation measurement step to measure the orientation of a magnetic domain of grain-oriented electromagnetic steel sheet based on the magnetic domain image, wherein the magnetic domain orientation measurement step generates a plurality of differentiated filter core sets by differentiating two-dimensional Gaussian functions of different spatial sizes in an X direction that corresponds to the direction orthogonal to the rolling direction of the grain-oriented electromagnetic steel sheet and in a Y direction that corresponds to the rolling direction of the grain-oriented electromagnetic steel sheet, for each of the two-dimensional Gaussian functions, applying the plurality of filter core sets. Petition 870250103202, 11 / 11 / 2025, p.48 / 103 4 / 9 differentiated respectively to the image of the magnetic domain and calculates square roots of the sums of squares of the respective filter outputs of the differentiated filter cores of the plurality of sets, and derives the orientation of the magnetic domain of the grain-oriented electromagnetic steel sheet based on the respective filter outputs of the differentiated filter cores of the set that has the largest square root of the sum of squares, among the plurality of sets of differentiated filter cores.

6. Magnetic domain structure analysis method according to claim 5, characterized in that it comprises a magnetic domain width correction step to correct the magnetic domain width of the grain-oriented electromagnetic steel sheet that was measured by the magnetic domain width measurement step, based on the magnetic domain orientation of the grain-oriented electromagnetic steel sheet that was measured by the magnetic domain orientation measurement step.

7. Non-transient computer-readable storage medium, characterized in that it comprises instructions which, when executed by one or more processors, cause the processors to perform: a magnetic domain image acquisition step to acquire a magnetic domain image by imaging a grain-oriented electromagnetic steel sheet; and a magnetic domain width measurement step to measure the width of a magnetic domain based on the magnetic domain image, wherein the magnetic domain width measurement step generates a plurality of filter cores of different spatial sizes by multiplying a complex one-dimensional Gabor filter. Petition 870250103202, dated 11 / 11 / 2025, p.49 / 103 5 / 9 by A in a spatial direction corresponding to a direction orthogonal to a lamination direction of the grain-oriented electromagnetic steel sheet, and by 1 / A in an amplitude direction, applies the plurality of filter cores respectively to the magnetic domain image and calculates an absolute value of the filter output per filter core, and derives the magnetic domain width of the grain-oriented electromagnetic steel sheet based on the spatial size of the filter core whose absolute value is the largest among the plurality of filter cores.

8. Means according to claim 7, characterized in that the processing comprises a magnetic domain orientation measurement step to measure the orientation of a magnetic domain of the grain-oriented electromagnetic steel sheet based on the magnetic domain image, wherein the magnetic domain orientation measurement step generates a plurality of differentiated filter core sets differentiating two-dimensional Gaussian functions of different spatial sizes in an X direction that corresponds to the direction orthogonal to the rolling direction of the grain-oriented electromagnetic steel sheet and in a Y direction that corresponds to the rolling direction of the grain-oriented electromagnetic steel sheet, for each of the two-dimensional Gaussian functions,applies the plurality of sets of differentiated filter cores respectively to the image of the magnetic domain and calculates square roots of the sums of squares of the respective filter outputs of the differentiated filter cores of the plurality of sets, and derives the orientation of the magnetic domain of the grain-oriented electromagnetic steel sheet based on the respective filter outputs of the differentiated filter cores of the set that has the largest square root of the sum of squares, among the plurality of sets of differentiated filter cores.

9. Means according to claim 8, characterized in that the processes comprise a magnetic domain width correction step to correct the magnetic domain width of the grain-oriented electromagnetic steel sheet that was measured by the magnetic domain width measurement step, based on the magnetic domain orientation of the grain-oriented electromagnetic steel sheet that was measured by the magnetic domain orientation measurement step.

10. Method for manufacturing a grain-oriented electromagnetic steel sheet, characterized in that it comprises: a magnetic domain structure analysis step to perform magnetic domain structure analysis, including derivation of the width of a magnetic domain of a grain-oriented electromagnetic steel sheet, using the magnetic domain structure analysis method as defined in any one of claims 4 to 6; and a groove forming or thermal deformation step to, based on the analysis results obtained by the magnetic domain structure analysis step, irradiate a laser beam onto a surface of the grain-oriented electromagnetic steel sheet being transported in a transport direction and thus form a plurality of grooves or thermal deformations, extending in a direction that crosses the transport direction, at a range in the transport direction.

11. Method for manufacturing a grain-oriented electromagnetic steel sheet according to claim 10, characterized in that, in a case where the surface of the grain-oriented electromagnetic steel sheet is divided into a first region in which the width W of a magnetic domain is the threshold value L or more and a second region in which the width W of the magnetic domain is less than the threshold value L, the groove formation or thermal deformation step includes the formation of a plurality of grooves or thermal deformations in the first region based on the results of the analysis obtained by the magnetic domain structure analysis step, and, given that a defined length that is a total of ideal lengths of each of the pluralities of grooves or thermal deformations formed in the first region is C, a length that is a total of differences between lengths and ideal lengths of each of the,Among the plurality of grooves or thermal deformations, grooves or thermal deformations in which the length of each is less than the width in a direction parallel to the direction of irradiation of the laser beam from the first region at the positions of the respective grooves or thermal deformations is D, a length that is the total difference between the ideal lengths and lengths of each of the grooves or thermal deformations, among the plurality of grooves or thermal deformations, grooves or thermal deformations in which the length of each is greater than the width in a direction parallel to the direction of irradiation of the laser beam from the first region at the positions of the respective grooves or thermal deformations is E, and an allowed length ratio corresponding to the defined length C of the plurality of grooves or thermal deformations is R, in the groove or thermal deformation formation step.The plurality of grooves or thermal deformations that satisfy the following formula (1) are formed in the first region by controlling the laser beam based on the results of the analysis. Petition 870250103202, dated 11 / 11 / 2025, page 52 / 103 8 / 9 (D+E) / C < R ...(1), 12. Grain-oriented electromagnetic steel sheet, characterized in that the grain-oriented electromagnetic steel sheet is manufactured by the method for manufacturing a grain-oriented electromagnetic steel sheet as defined in claim 10, and, in a case where a surface of the grain-oriented electromagnetic steel sheet is divided into a first region in which the width W of a magnetic domain of the grain-oriented electromagnetic steel sheet is the limiting value L or more and a second region in which the width W of the magnetic domain of the grain-oriented electromagnetic steel sheet is less than the limiting value L, the surface of the grain-oriented electromagnetic steel sheet includes a plurality of grooves or thermal deformations formed in the first region, and, given that a defined length that is a sum of ideal lengths of each of the pluralities of grooves or thermal deformations formed in the first region is C,a length that is the total difference between lengths and ideal lengths of each of the, among the plurality of grooves or thermal deformations, grooves or thermal deformations in which a length of each of them is less than a width in a direction parallel to a direction of irradiation of the laser beam from the first region at the positions of the respective grooves or thermal deformations is D, a length that is the total difference between lengths and ideal lengths of each of the, among the plurality of grooves or thermal deformations, grooves or thermal deformations in which a length of each of them is greater than a width in a direction parallel to the direction of irradiation of the laser beam from the first region at the positions of the respective grooves or thermal deformations is E,and a length ratio allowed corresponding to the defined length C of the plurality of grooves or thermal strains is R, the plurality of grooves or thermal strains that satisfy the following formula (1) are formed in the first region. (D+E) / C < R ...(1), 13. Iron core, characterized in that it is manufactured using grain-oriented electromagnetic steel sheet as defined in claim 12.

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