Polar and in-plane magnetism synchronous detection method

Abstract

The invention provides a polar and in-plane magnetism synchronous detection method, which is characterized in that polarized light is used as detection light and is converged to a detected position of a detected object through an objective lens, the detection light entering the detected position is symmetrical along the normal of the detected position, and the detection light is reflected by the detected object and then enters a photoelectric sensor through the objective lens and an analyzer; the photoelectric sensor at least comprises two photosensitive areas, the symmetry axis of detection light entering the photoelectric sensor is a first axis, and the at least two photosensitive areas are symmetrical along the first axis; calculating the polar magnetism of the measured position at least according to the sum of the signals of the photosensitive areas symmetrical along the first axis; and calculating the in-plane magnetism of the measured position at least according to the difference of the signals of the photosensitive areas symmetrical along the first axis. When the polar magnetism and the in-plane magnetism of the detected object are detected, light path switching is not needed, detection is convenient, the obtained polar magnetism and the obtained in-plane magnetism do not have the dislocation problem, and the detection precision of the in-plane magnetism can be improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of nondestructive testing, and relates to the detection of the magnetism of an object. Specifically, it relates to a method for synchronously detecting polar and in-plane magnetism. Background Art

[0002] The magneto-optical Kerr effect refers to the fact that the reflected light will change due to the magnetization state of the reflecting medium. Therefore, the magnetism of the object to be measured can be obtained by detecting the reflected light on the surface of the object to be measured. On this basis, a magnetic detection device based on the magneto-optical Kerr effect emits polarized light to the object to be measured and measures the polarization state of the reflected light of the object to be measured, so as to measure the magnetism on the surface of the object to be measured. In some cases, for the magnetic state of the object to be measured, it is necessary to select to use the polar magneto-optical Kerr effect or the longitudinal magneto-optical Kerr effect to detect the object to be measured. The polar magneto-optical Kerr effect requires the incident light to be perpendicularly incident on the object to be measured to obtain a better detection effect, and the longitudinal Kerr effect requires the incident light to be obliquely incident on the object to be measured and the incident plane of the incident light to be parallel to the direction of the measured magnetic domain to obtain a better detection effect.

[0003] Existing magnetic detection devices based on the magneto-optical Kerr effect usually use obliquely incident polarized light to realize the detection of the longitudinal magneto-optical Kerr effect, and use perpendicularly incident polarized light to realize the detection of the polar magneto-optical Kerr effect. In order to detect the polar magneto-optical Kerr effect and the longitudinal magneto-optical Kerr effect of the same object to be measured, two different optical paths need to be set, and it is difficult to align the two optical paths to the same position of the object to be measured, which will cause it difficult to match the detection positions of the polar detection result and the longitudinal detection result.

[0004] The above information disclosed in the background art section is only used to enhance the understanding of the background of the present invention, and therefore may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Invention

[0005] Aiming at the problem that it is difficult to match the detection positions of the polar detection result and the longitudinal detection result existing in the prior art, the present application provides a method for synchronously detecting polar and in-plane magnetism. Polarized light is used as the detection light and is converged to the measured position of the object to be measured through an objective lens. The detection light incident on the measured position is symmetric about the normal line of the measured position. The detection light is reflected by the object to be measured and then passes through the objective lens, a polarizer and is incident on a photoelectric sensor; the photoelectric sensor includes at least two photosensitive regions. The symmetry axis of the detection light incident on the photoelectric sensor is the first axis, and at least two of the photosensitive regions are symmetric about the first axis; at least calculate the polar magnetism of the measured position according to the sum of the signals of the photosensitive regions symmetric about the first axis; at least calculate the in-plane magnetism of the measured position according to the difference between the signals of the photosensitive regions symmetric about the first axis.

[0006] According to the description of an embodiment of the present application, the photoelectric sensor includes four of the photosensitive regions, the four photosensitive regions are arranged in an orthogonal direction, and the first axis passes through the intersection of the orthogonal directions.

[0007] According to the description of an embodiment of the present application, at least based on the sum of the signals of the four photosensitive regions, calculate the polar magnetism of the measured position; Divide the four photosensitive regions into two groups according to one of the symmetry axes arranged in the orthogonal direction, use the sum of the signals of the photosensitive regions in the same group as the secondary signal, and calculate the difference between the two secondary signals to calculate the in-plane magnetism of the measured position.

[0008] According to the description of an embodiment of the present application, divide the four photosensitive regions into two groups according to the other of the symmetry axes arranged in the orthogonal direction, use the sum of the signals of the photosensitive regions in the same group as the secondary signal, and calculate the difference between the two secondary signals to calculate the in-plane magnetism of the measured position in another direction.

[0009] According to the description of an embodiment of the present application, the photoelectric sensor includes a plurality of the photosensitive regions and forms a photosensitive array, and the detection light is irradiated on at least part of the photosensitive regions in the photosensitive array.

[0010] According to the description of an embodiment of the present application, the photosensitive regions irradiated by the detection light are symmetric about the first axis.

[0011] According to the description of an embodiment of the present application, symmetrically select the photosensitive regions irradiated by the detection light along the first axis and divide them into two groups; Calculate the polar magnetism of the measured position according to the sum of the signals of the selected photosensitive regions; Use the sum of the signals of the photosensitive regions in the same group as the secondary signal, and calculate the difference between the two secondary signals to calculate the in-plane magnetism of the measured position.

[0012] According to the description of an embodiment of the present application, the detection light incident on the objective lens is annular light.

[0013] According to the description of an embodiment of the present application, the detection light is incident on the objective lens after passing through the beam splitter; after the detection light reflected by the measured object exits the objective lens, it is incident on the photoelectric sensor after passing through the beam splitter.

[0014] According to the description of an embodiment of the present application, the first axis is coaxial with the optical axis of the objective lens.

[0015] The present invention has at least the following beneficial effects: By processing the signals of multiple photosensitive regions, the detection of the polar and in-plane magnetism of the object to be measured can be achieved using the same detection light, without the need for optical path switching. The detection is convenient and there is no misalignment problem between the detected polar and in-plane magnetism. On the other hand, by taking the difference of the signals of the corresponding photosensitive regions to enhance the intensity of the longitudinal magneto-optical Kerr signal and reduce noise, the detection accuracy of the in-plane magnetism can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a configuration mode of the device involved in the detection method provided by the present invention.

[0017] Figure 2 This is a form of the detection light between the objective lens and the object to be measured.

[0018] Figure 3 This is a form of the detection light between the objective lens and the object to be measured.

[0019] Figure 4 This is a form of the detection light between the objective lens and the object to be measured.

[0020] Figure 5 This is a form of the relationship between the detection light and the photosensitive regions on the photoelectric sensor.

[0021] Figure 6 This is a form of the photosensitive regions on the photoelectric sensor.

[0022] Figure 7 This is a form of the photosensitive regions on the photoelectric sensor.

[0023] Figure 8 This is a form of the photosensitive regions on the photoelectric sensor.

[0024] Figure 9 This is a form of the relationship between the detection light and the photosensitive regions on the photoelectric sensor.

[0025] Figure 10 This is a configuration mode of the device involved in the detection method provided by the present invention.

[0026] Figure 11 This is a form of the detection light between the objective lens and the object to be measured.

[0027] Figure 12 This is a form of the relationship between the detection light and the photosensitive regions on the photoelectric sensor.

[0028] Figure 13 This is a form of the relationship between the detection light and the photosensitive regions on the photoelectric sensor.

[0029] In the figure, 1 is a light source; 2 is a polarizer; 3 is a beam splitter; 4 is an objective lens; 5 is a test object; 6 is an analyzer; 7 is a photoelectric sensor; 71 is a photosensitive area; 71A is the first photosensitive area; 71B is the second photosensitive area; 71C is the third photosensitive area; 71D is the fourth photosensitive area; 81 is an in-plane magnetization assembly; 82 is an axial magnetization assembly; LN is a normal line; G is a detection light; G1 is a sub-beam; G2 is a sub-beam; LG is a first axis; S is an irradiation area; S1 is an irradiation area; S2 is an irradiation area; S3 is an irradiation area; S41 is an irradiation area; S42 is an irradiation area; L1 is a symmetry axis; L71 is a symmetry axis; L72 is a symmetry axis. Detailed implementation manners

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. It should be noted that the accompanying drawings are all in a very simplified form and use non-precise ratios, only for the purpose of facilitating and clearly assisting in explaining the objectives of the embodiments of the present invention.

[0031] The present invention provides a method for synchronously detecting axial and in-plane magnetism, which uses the magneto-optical Kerr effect to detect the axial and in-plane magnetism of a test object.

[0032] The detection light G is polarized light. For the formation method of the detection light G, as a relatively common method, a polarizer 2 can be set in the optical path of the incident test object 5 to convert unpolarized light into polarized light; for the polarizer 2, devices such as a polarizing sheet, a crystal polarizer, a polarimeter, a dichroic crystal, and a wire grid polarizer can be used, or the Brewster angle can be used to form polarized light, which can be specifically set and adjusted according to needs.

[0033] The detection light G is focused by the objective lens 4 onto the test position of the test object 5, and the detection light G incident on the test position is symmetric along the normal line LN of the test position. It should be noted that the detection light G incident on the test position being symmetric along the normal line LN of the test position means that the incident direction of the light is symmetric along the normal line LN, rather than the optical path of the incident light G being completely symmetric along the normal line LN; for example, for the sub-beam G1 of the detection light G, it is incident on the test object 5 at a preset incident angle, and correspondingly, there is a sub-beam G2 of the detection light G that is symmetric with the sub-beam G1 along the normal line LN.

[0034] Please refer to Figure 2, showing a specific form, in which, for the detection light G incident on the object 5 between the objective lens 4 and the object 5 to be measured, the axis of the conical region formed by the detection light G is coaxial with the normal LN of the measured position of the object 5 to be measured. Accordingly, on the same incident plane, the detection light G incident on the measured position is symmetric along the normal LN of the measured position.

[0035] Please refer to Figure 3 , Figure 4 , showing the positional relationships of several other forms of the objective lens 4, the object 5 to be measured, and the detection light G. Among them, as Figure 3 shown, even if the focal plane of the objective lens 4 forms an angle with the plane where the measured position of the object 5 to be measured is located, it is still possible to make the detection light G incident on the measured position symmetric along the normal LN of the measured position by configuring corresponding devices and / or the detection light G; as Figure 4 shown, even if the detection light G incident on the objective lens 4 forms an angle with the axis of symmetry of the objective lens 4, it is still possible to make the detection light G incident on the measured position symmetric along the normal LN of the measured position by configuring corresponding devices and / or the detection light G; and, other configuration methods. That is to say, it is possible to make the detection light G incident on the measured position symmetric along the normal LN of the measured position by configuring at least one of the objective lens 4, the object 5 to be measured, and the detection light G.

[0036] Since the detection light G incident on the measured position is symmetric along the normal LN of the measured position, the detection light G reflected by the measured position of the object 5 is also symmetric along the normal LN of the measured position. More specifically, for the sub-beams G1 and G2 of the detection light G that are symmetric along the normal LN of the measured position, the sub-beam G1 incident on the object 5 to be measured will propagate in the opposite direction of the sub-beam G2 after being reflected by the object 5, and the sub-beam G2 incident on the object 5 to be measured will propagate in the opposite direction of the sub-beam G1 after being reflected by the object 5.

[0037] After the detection light G is reflected by the object 5 to be measured, it passes through the objective lens 4, the polarizer 6 and is incident on the photoelectric sensor 7. The photoelectric sensor 7 can form a matching electrical signal according to the light intensity of the received light; by reading the electrical signal of the photoelectric sensor 7, the light intensity of the detection light G irradiated on the photoelectric sensor 7 can be obtained. Combining the characteristic that the polarizer 6 converts the polarization state of the detection light G into a light intensity characteristic, the influence of the magneto-optical Kerr effect on the polarization state of the detection light G can be analyzed, and then the magnetism of the measured position of the object 5 to be measured can be calculated.

[0038] The photoelectric sensor 7 includes at least two photosensitive regions 71. The axis of symmetry of the detection light G incident on the photoelectric sensor 7 is the first axis LG, and at least two photosensitive regions 71 are symmetric along the first axis LG; at least calculate the polar magnetic property of the measured position according to the sum of the signals of the photosensitive regions 71 symmetric along the first axis LG; at least calculate the in-plane magnetic property of the measured position according to the difference between the signals of the photosensitive regions 71 symmetric along the first axis LG.

[0039] Please refer to Figure 5 , which shows a specific situation where the detection light G irradiates the photosensitive area 71 of the photosensor 7. Among them, the photosensor 7 is provided with two photosensitive areas 71; the irradiation area S of the detection light G can be either an irradiation area S1 larger than the range of the photosensitive area 71 or an irradiation area S2 smaller than the range of the photosensitive area 71, as long as the photosensor 7 can obtain an electrical signal corresponding to the light intensity formed by the detection light G irradiating the photosensitive area 71.

[0040] Since the detection light G incident on the measured object 5 is symmetric with respect to the normal line LN of the measured position, therefore, except for the detection light G incident along the normal line LN of the measured position, the remaining detection lights all have corresponding non-zero incident angles, and at least the polar magneto-optical Kerr signal and the longitudinal magneto-optical Kerr signal are carried in the corresponding detection light G. Corresponding to the irradiation area S of the detection light G on the photosensitive area 71 of the photosensor 7, except for the detection light G incident along the first axis LG, the detection lights at other positions all carry at least the polar magneto-optical Kerr signal and the longitudinal magneto-optical Kerr signal; since there is at least a photosensitive area 71 symmetric about the symmetry axis of the detection light G, the detection light G received by the photosensitive area 71 at least includes the polar magneto-optical Kerr signal and the longitudinal magneto-optical Kerr signal. Therefore, the polar magneto-optical Kerr signal and the longitudinal magneto-optical Kerr signal can be analyzed through the signal of the photosensitive area 71 of the photosensor 7, and then the polar magnetism and in-plane magnetism of the measured object can be analyzed.

[0041] When it is necessary to calculate the polar magneto-optical Kerr effect to analyze the polar magnetism, the detection light G can be regarded as a whole to consider the detection light G as a polarized light vertically incident on the measured object 5. By taking the signal of the photosensitive area 71 symmetric about the symmetry axis of the detection light G as a whole, that is, at least summing the signals of the corresponding photosensitive area 71, the polar magneto-optical Kerr signal can be analyzed, and then the polar magnetism of the measured position of the measured object 5 can be analyzed.

[0042] When it is necessary to calculate the longitudinal magneto - optical Kerr effect to analyze in - plane magnetism, the detection light G can be divided into several parts. Accordingly, for the detection light G received by one photosensitive area 71, it can be regarded as the detection light G obliquely incident on the object 5 to be measured; the detection lights G received by the photosensitive areas 71 symmetric about the first axis LG are respectively the detection lights G incident on the object 5 to be measured in directions symmetric about the normal LN. When both sub - beams G1 and G2 pass through the same polarizer 6 and the polarizer 6 weakens the light intensity of the detection light G passing through it, since the sub - beams G1 and G2 are symmetrically incident on the object 5 to be measured along the normal LN of the object 5, the ways of light - intensity change of the sub - beams G1 and G2 after passing through the polarizer 6 are different. For example, the light intensity of the sub - beam G1 passing through the polarizer 6 increases, and the light intensity of the sub - beam G2 passing through the polarizer 6 decreases; in this case, by taking the difference between the signals of the photosensitive areas 71 symmetric about the first axis LG, the influence degree of the longitudinal magneto - optical Kerr signal on the light intensity can be amplified, and then the intensity of the longitudinal magneto - optical Kerr signal can be enhanced, and thus the in - plane magnetism of the measured position of the object 5 to be measured can be obtained.

[0043] Through the foregoing method, by processing the signals of multiple photosensitive areas 71, the detection of the polar and in - plane magnetism of the object 5 to be measured can be realized using the same detection light G without the need for optical path switching. The detection is convenient and there is no problem of misalignment between the detected polar and in - plane magnetism; on the other hand, by taking the difference between the signals of the corresponding photosensitive areas 71 to enhance the intensity of the longitudinal magneto - optical Kerr signal and reduce noise, the detection accuracy of the in - plane magnetism can be improved.

[0044] In some cases, as Figure 5 shown, two photosensitive areas 71 can be set on the photoelectric sensor 7, and the two photosensitive areas 71 are symmetric about the first axis LG, then the detection of the polar and in - plane magnetism can be realized. In addition, other forms of photoelectric sensors 7 can also be set. As Figure 6 shown, the number of photosensitive areas 71 can be set to 4. As Figure 7 shown, there can be a gap between the photosensitive areas 71. As Figure 8 shown, multiple photosensitive areas 71 can be arranged in an array.

[0045] Please refer to Figure 6 , the photoelectric sensor 7 includes four photosensitive areas 71. The four photosensitive areas 71 are arranged in an orthogonal direction. According to the quadrants formed by the orthogonal direction, the symmetry axes L71 and L72 arranged in the orthogonal direction divide the four photosensitive areas 71 into the first photosensitive area 71A, the second photosensitive area 71B, the third photosensitive area 71C, and the fourth photosensitive area 71D. The first axis LG passes through the intersection point of the orthogonal directions. In this case, the irradiation area S formed by the detection light G will irradiate the four photosensitive areas 71 approximately evenly.

[0046] When set as Figure 6When in the form of the photoelectric sensor 7 shown, calculate the polar magnetism of the measured position based on at least the sum of the signals of the four photosensitive regions 71. Specifically, sum the first photosensitive region 71A, the second photosensitive region 71B, the third photosensitive region 71C, and the fourth photosensitive region 71D, so as to equivalent the detection light G irradiated on the photosensitive region 71 to the form of being perpendicularly incident on the measured object 5.

[0047] When set in the form of the photoelectric sensor 7 as Figure 6 shown, the four photosensitive regions 71 can be divided into two groups according to one of the symmetry axes L71 and L72. Take the sum of the signals of the photosensitive regions 71 in the same group as the secondary signal, and calculate the difference between the two secondary signals to calculate the in-plane magnetism of the measured position.

[0048] Specifically, please refer to Figure 6 , group the photosensitive regions 71 with the horizontal symmetry axis L72, that is, take the first photosensitive region 71A and the second photosensitive region 71B as the first group, and the third photosensitive region 71C and the fourth photosensitive region 71D as the second group; for the first photosensitive region 71A and the second photosensitive region 71B in the first group, the detection light G they receive can be equivalent to the detection light obliquely incident on the measured object 5 along the other symmetry axis L71. Sum the signals of the first photosensitive region 71A and the second photosensitive region 71B as the secondary signal, and the secondary signal can be used to calculate the corresponding longitudinal magneto-optical Kerr effect, and then analyze the in-plane magnetism of the measured object 5 at least along the direction of the symmetry axis L71; the same applies to the second group. On this basis, further take the difference between the secondary signals corresponding to the first group and the second group to enhance the intensity of the longitudinal magneto-optical Kerr signal and improve the detection accuracy of the in-plane magnetism along the direction of the symmetry axis L71.

[0049] As another method, group the photosensitive regions 71 with the vertical symmetry axis L71, that is, take the first photosensitive region 71A and the fourth photosensitive region 71D as the first group, and the second photosensitive region 71B and the third photosensitive region 71C as the second group, for the detection accuracy of the in-plane magnetism along the direction of the symmetry axis L72.

[0050] That is to say, when there are at least four photosensitive regions 71 and they can form a symmetric form along the orthogonal directions, and the symmetry axis of the detection light G, the first axis LG, is located at the intersection of the orthogonal directions. In this case, only by changing the data processing method can the in-plane magnetism in two orthogonal directions be detected, without the need for optical path switching, greatly improving the usage efficiency, and at the same time, there is no error caused by optical path switching.

[0051] The optoelectronic sensor 7 may also be in a form including multiple photosensitive regions 71 and forming a photosensitive array. At this time, the detection light G irradiates at least some of the photosensitive regions in the photosensitive array. On this basis, according to the relative position between the first axis LG of the symmetry axis of the detection light G and the photosensitive region 71, corresponding photosensitive regions 71 can be selected according to the detection requirements and their signals can be analyzed.

[0052] As a feasible method, the symmetry axis L71 can be set according to the relative position between the first axis LG and the photosensitive region 71, and the photosensitive regions 71 symmetric along the symmetry axis L71 can be selected according to the irradiation region S of the detection light G, so as to be used as the basis for analyzing the magneto-optical Kerr effect of the object 5 to be measured.

[0053] Specifically, the photosensitive regions 71 irradiated by the detection light G can be symmetrically selected along the first axis LG and divided into two groups, and the signals of the selected photosensitive regions 71 can be used to analyze the polar and longitudinal magnetism of the measured position of the object to be measured. For example, the polar magnetism of the measured position can be calculated according to the sum of the signals of the selected photosensitive regions 71; the sum of the signals of the photosensitive regions 71 in the same group can be used as a secondary signal, and the difference between the two secondary signals can be calculated to calculate the in-plane magnetism of the measured position.

[0054] Please refer to Figure 8 , which shows a feasible implementation manner. Among them, according to the position of the first axis LG on the photosensitive region 71, the symmetry axis L71 is set, and the photosensitive regions A2 and D2 are symmetrically selected along the first axis LG to form the first group, and the photosensitive regions B2 and C2 form the second group; on this basis, the signals of the photosensitive regions A2, B2, C2, and D2 can be at least summed to calculate the polar magnetism of the measured position of the object 5 to be measured, and the secondary signals of the first group and the secondary signals of the second group can be at least subtracted to calculate the in-plane magnetism of the measured position of the object 5 to be measured. For the specific calculation method, please refer to the foregoing content and will not be elaborated here. Correspondingly, another symmetry axis L72 can also be selected, and the corresponding photosensitive regions can be selected to calculate the polar and in-plane magnetism of the object 5 to be measured.

[0055] It should be noted that in order to make the sum of the signals of the selected photosensitive regions 71 be used as the basis for analyzing the polar magnetism of the object to be measured, it is necessary to make the selected photosensitive regions 71 symmetric along the first axis LG, so that the detection light G corresponding to each photosensitive region 71 can be equivalent to the form of perpendicular incidence on the object 5 to be measured.

[0056] Please refer to Figure 8, in some cases, the orthogonal symmetry axes L71 and L72 can be set according to the position of the first axis LG, and the photosensitive area 71 in the irradiation area S is divided into four quadrants. The photosensitive areas A1 - A3 in the first quadrant, the photosensitive areas B1 - B3 in the second quadrant, the photosensitive areas C1 - C3 in the third quadrant, and the photosensitive areas D1 - D3 in the fourth quadrant are respectively selected as the photosensitive area 71 participating in the calculation, and the polar and in-plane magnetism of the object 5 to be measured are calculated according to the foregoing method. The specific calculation method will not be elaborated here.

[0057] It should be noted that, in some cases, the array - shaped photosensitive area 71 may have a relatively large number of photosensitive areas 71. When using the solution provided by the present application, the signals of the corresponding photosensitive areas 71 can be selected to analyze the magnetic characteristics of the object 5 to be measured. In some cases, it can be manifested as using the brightness / gray level or approximate signals of some areas in the image to analyze the magnetic characteristics of the object 5 to be measured. For the specific analysis method, please refer to the foregoing content and will not be elaborated here.

[0058] For the detection light G, only a symmetry axis is required; for the specific form of the detection light G, it can be a complete beam of light to form a circular light spot on the photoelectric sensor 7, for example Figures 5 - 8 the situation shown; it can also be an annular light to form an annular light spot on the photoelectric sensor 7, for example Figure 9 the situation shown; it can also be a combination of multiple beams of light to form a symmetric light spot on the photoelectric sensor 7, for example Figures 12 - 13 the situation shown; or other shapes or forms of light beams to form a generally symmetric light spot on the photoelectric sensor 7.

[0059] For the case where the detection light G is an annular light, please refer to Figure 9 , still according to the symmetry axis of the annular light, the first axis LG, the corresponding photosensitive area 71 can be selected for analyzing the corresponding polar and in - plane magnetism. In particular, even if the detection light G does not include the light incident along the normal line LN direction of the measured position of the object 5 to be measured, since the detection light G incident on the object 5 from other directions still carries the signal of the magneto - optical Kerr effect, the polar magnetism can still be obtained by the foregoing method accordingly.

[0060] For the case where the detection light G is a symmetric multi - beam of light, please refer to Figure 11, it is still possible to select a corresponding photosensitive area 71 according to the symmetry axis of multiple beams of light, i.e., the first axis LG, for analyzing the corresponding polar and in-plane magnetisms. Similar to the case of annular light, even if the detection light G does not include light incident along the normal LN direction of the measured position of the object 5 to be measured, since the detection light G incident on the object 5 from other directions still carries the signal of the magneto-optical Kerr effect, it is still possible to obtain the polar magnetism by the foregoing method accordingly.

[0061] For the case where the detection light G is a symmetric multiple-beam light, it can be, as Figure 10 shown, in the form of setting multiple light sources 1 to emit corresponding light. For example, when the detection light G is a two-beam light, the first light source 11 and the second light source 12 can be set, and corresponding optical devices can be configured to make the detection light G meet the detection requirements; it can also be based on the Figure 1 scheme shown, on the basis of one light source 1, a beam decomposition component is set to form multiple beams of light.

[0062] It should be noted that when setting multiple light sources 1 to emit corresponding light, it is necessary to make the properties of the light emitted by the multiple light sources 1 substantially the same to reduce the differences caused by the light sources 1 between multiple light spots and avoid affecting the detection accuracy.

[0063] Please refer to Figure 10 , which shows a form using two light sources 1. Among them, the first light source 11 and the second light source 12 are arranged in parallel and symmetric along the symmetry axis L1; the light emitted by the first light source 11 and the second light source 12 is incident on the objective lens 4 in a parallel and symmetric manner, and after passing through the objective lens 4, it is symmetrically incident on the object 5 to be measured along the discovery LN direction of the measured position of the object 5. Please refer to Figure 11 , similar to the foregoing content, even if there is a combination of multiple detection light beams G forming a light beam, even if the symmetry axis of the multiple detection light beams G, i.e., the first axis LG, forms an angle with the optical axis of the objective lens 4, or the optical axis of the objective lens 4 forms an angle with the discovery LN of the measured position of the object 5 to be measured, it is possible to adjust the corresponding optical devices to make the detection light incident on the object 5 symmetric along the normal LN of the measured position.

[0064] Please refer to Figure 12 , which shows a form using two beams of light as the detection light G. Among them, the two beams of light form two irradiation areas S41 and S42 on the photosensitive area 71, and the two irradiation areas S41 and S42 are respectively irradiated on two photosensitive areas 71A and 71B. On this basis, since the detection light G corresponding to the irradiation areas S41 and S42 both carry the polar and longitudinal magneto-optical Kerr signals, it is possible to analyze the polar and in-plane magnetisms of the object 5 to be measured by analyzing the signals of the photosensitive areas 71A and 71B corresponding to the two irradiation areas S41 and S42. For the specific analysis method, please refer to the foregoing content and will not be elaborated here.

[0065] Please refer to Figure 13 , which shows a form in which two beams of light are used as detection light G and the photosensitive regions 71 are formed in an array. The two beams of light form two irradiation regions S41 and S42 on the photosensitive region 71. The irradiation region S41 irradiates on the photosensitive regions A1, A2, A3, and A4 as the first group; the irradiation region S42 irradiates on the photosensitive regions B1, B2, B3, and B4 as the second group. On this basis, since the detection light G corresponding to the irradiation regions S41 and S42 both carry the polar and longitudinal magneto-optical Kerr signals, the polar and in-plane magnetism of the object 5 to be measured can be analyzed by analyzing the signals of the first group and the second group of photosensitive regions corresponding to the two irradiation regions S41 and S42. For the specific analysis method, please refer to the foregoing content and will not be elaborated here.

[0066] In some cases, since there is a common optical path between the detection light G incident on the object 5 to be measured and the detection light G reflected by the object 5 to be measured, corresponding optical devices need to be set to separate the incident light and the reflected light so as to facilitate the detection of the reflected light. Correspondingly, a beam splitter 3 can be set in the optical path, so that the detection light G incident on the object 5 to be measured is incident on the objective lens 4 after passing through the beam splitter 3, and the detection light G reflected by the object 5 to be measured is incident on the photoelectric sensor 7 after passing through the beam splitter 3 after exiting the objective lens 4.

[0067] In some cases, in order to facilitate the setting of the optical path, the first axis LG can be coaxial with the optical axis of the objective lens 4 to more conveniently obtain the detection light G symmetric about the normal LN direction of the measured position of the object 5 to be measured.

[0068] In some cases, as Figure 1 , Figure 10 shown, several exciting devices can also be set near the object 5 to be measured; the exciting device is used to generate a magnetic field acting on the object 5 to be measured to change the magnetization direction of the object 5 to be measured, at least for obtaining the hysteresis loop.

[0069] As a feasible implementation manner, the exciting component can include at least one of an in-plane exciting component 81 and a polar exciting component 82. The polar exciting component 82 is configured to enable the magnetic field to extend at least in a direction perpendicular to the measured surface of the object 5 to be measured; the in-plane exciting component 82 is configured to enable the magnetic field to extend at least in a direction parallel to the measured surface of the object 5 to be measured. The exciting component can be an exciting coil, an electromagnet, or other forms of components capable of generating a magnetic field.

[0070] The above has shown and described the basic principles, main features and advantages of the present invention. Therefore, the above is only an embodiment of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification is only the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention also includes various equivalent changes and improvements, and these changes and improvements will all fall within the scope of the present invention claimed.

Claims

1. A method for synchronous detection of polar and in-plane magnetism, characterized in that: Using polarized light as the detection light, which is converged by an objective lens to the measured position of the object to be measured. The detection light incident on the measured position is symmetric along the normal of the measured position. After being reflected by the object to be measured, the detection light passes through the objective lens, a polarizer, and is incident on a photoelectric sensor. The photoelectric sensor includes at least two photosensitive regions. The symmetry axis of the detection light incident on the photoelectric sensor is the first axis, and at least two of the photosensitive regions are symmetric along the first axis. Calculating the polar magnetism of the measured position at least according to the sum of the signals of the photosensitive regions symmetric along the first axis; calculating the in-plane magnetism of the measured position at least according to the difference between the signals of the photosensitive regions symmetric along the first axis.

2. The in-plane and polar magnetic synchronization detection method according to claim 1, wherein: The photoelectric sensor includes four photosensitive regions, and the four photosensitive regions are arranged in an orthogonal direction, and the first axis passes through the intersection of the orthogonal directions.

3. A method for detecting in-plane and polar magnetic synchronization as described in claim 2, characterized in that: Calculating the polar magnetism of the measured position at least according to the sum of the signals of the four photosensitive regions. Dividing the four photosensitive regions into two groups according to one of the symmetry axes arranged in the orthogonal direction, using the sum of the signals of the photosensitive regions in the same group as a secondary signal, and calculating the difference between the two secondary signals to calculate the in-plane magnetism of the measured position.

4. A method for synchronously detecting in-plane and polar magnetism according to claim 3, characterized in that: Dividing the four photosensitive regions into two groups according to the other of the symmetry axes arranged in the orthogonal direction, using the sum of the signals of the photosensitive regions in the same group as a secondary signal, and calculating the difference between the two secondary signals to calculate the in-plane magnetism of the measured position in the other direction.

5. A method for detecting the in-plane and longitudinal magnetic fields as claimed in claim 1, wherein: The photoelectric sensor includes a plurality of photosensitive regions and forms a photosensitive array, and the detection light irradiates at least some of the photosensitive regions in the photosensitive array.

6. The method for detecting the in-plane and polar magnetic synchronization according to claim 5, wherein: The photosensitive regions irradiated by the detection light are symmetric along the first axis.

7. A method for detecting the in-plane and polar magnetism synchronously according to claim 6, characterized in that: Selecting and dividing the photosensitive regions irradiated by the detection light that are symmetric along the first axis into two groups. Calculating the polar magnetism of the measured position according to the sum of the signals of the selected photosensitive regions. Using the sum of the signals of the photosensitive regions in the same group as a secondary signal, and calculating the difference between the two secondary signals to calculate the in-plane magnetism of the measured position.

8. A method for detecting the in-plane and polar magnetic synchronization according to claim 1, characterized in that: The detection light incident on the objective lens is annular light.

9. The method for detecting the in-plane and polar magnetism synchronously according to claim 1, wherein: The detection light is incident on the objective lens after passing through a beam splitter; after the detection light reflected by the object to be measured exits the objective lens, it passes through the beam splitter and is incident on the photoelectric sensor.

10. A method for detecting the in-plane and polar magnetism synchronously according to claim 1, characterized in that: The first axis is coaxial with the optical axis of the objective lens.

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