Polar and in-plane magnetism synchronous detection device

Abstract

The utility model provides a polar and in-plane magnetism synchronous detection device which comprises a light source, a polarizer, a spectroscope, an objective lens, a polarization analyzer and a sensor, detection light emitted by the light source passes through the polarizer, the spectroscope and the objective lens and symmetrically enters a detected object along a normal of a detected surface of the detected object; the detection light reflected by the detected object passes through the objective lens, the spectroscope and the analyzer and then enters the sensor; the sensor comprises at least two photosensitive areas, and the at least two photosensitive areas are symmetrically arranged along the symmetry axis of the detection light. The synchronous detection of the polarity and in-plane magnetism of the detected object can be realized by using the same detection light, the switching of light paths is not needed, the detection is convenient, and the obtained polarity and in-plane magnetism do not have the problem of dislocation.

Description

Technical Field

[0001] This utility model belongs to the field of nondestructive testing technology and relates to the magnetic detection of the tested object, specifically to a device for simultaneous detection of polar and in-plane magnetic properties. Background Technology

[0002] The magneto-optical Kerr effect refers to the change in reflected light due to the magnetization state of the reflecting medium. Therefore, the magnetism of an object can be obtained by detecting the reflected light from its surface. Based on this, magnetic detection devices using the pole-and-magnetic-optical Kerr effect measure the magnetism of the object's surface by emitting polarized light towards it and measuring the polarization state of the reflected light. In some cases, to determine the magnetic state of an object, it is necessary to select either the poloidal or longitudinal magneto-optical Kerr effect for detection. The poloidal magneto-optical Kerr effect requires the incident light to be perpendicular to the object for better detection results, while the longitudinal Kerr effect requires the incident light to be angled and the incident surface of the light to be parallel to the direction of the magnetic domains being measured for better detection results.

[0003] Existing magnetic detection devices based on the magneto-optical Kerr effect typically use obliquely incident polarized light to detect the longitudinal magneto-optical Kerr effect and perpendicularly incident polarized light to detect the poloidal magneto-optical Kerr effect. However, to detect both the poloidal and longitudinal magneto-optical Kerr effects on the same object, two different optical paths are required. Furthermore, it is difficult to align these two paths with the same location on the object, making it challenging to match the poloidal and longitudinal detection results at the correct detection position.

[0004] The information disclosed in the background section is only intended to enhance the understanding of the background of this utility model, and therefore may contain information that does not constitute prior art known to those skilled in the art. Utility Model Content

[0005] To address the technical problem of difficulty in matching the detection position between pole and longitudinal detection results in existing technologies, this invention provides a pole and in-plane magnetic synchronous detection device, comprising a light source, a polarizer, a beam splitter, an objective lens, an analyzer, and a sensor. The detection light emitted by the light source passes through the polarizer, beam splitter, and objective lens and is symmetrically incident on the test object along the normal of the test surface. The detection light reflected by the test object passes through the objective lens, beam splitter, and analyzer and is incident on the sensor. The sensor includes at least two photosensitive areas, which are symmetrically arranged along the axis of symmetry of the detection light.

[0006] According to one embodiment of the present invention, the sensor includes two photosensitive areas, and detection light is symmetrically irradiated on the two photosensitive areas.

[0007] According to one embodiment of the present invention, the sensor includes four photosensitive areas, and detection light is symmetrically irradiated onto the four photosensitive areas.

[0008] According to one embodiment of the present invention, the light source includes a first sub-light source emitting a first sub-detection light and a second sub-light source emitting a second sub-detection light. The first sub-detection light and the second sub-detection light are symmetrically incident on the test object along the normal of the test surface.

[0009] According to one embodiment of this utility model, the first sub-detection light emitted by the first sub-light source and the second sub-detection light emitted by the second sub-light source have the same light intensity.

[0010] According to one embodiment of the present invention, the polar and in-plane magnetic synchronous detection device further includes a magnetic field generating device, which is configured to generate a magnetic field at the measured position of the object being measured.

[0011] According to one embodiment of the present invention, the magnetic field generating device includes at least one of a poloidal excitation device and an in-plane excitation device. The poloidal excitation device is configured to generate a magnetic field in a direction perpendicular to the measured surface of the object being measured, and the in-plane excitation device is configured to generate a magnetic field in a direction parallel to the measured surface of the object being measured.

[0012] According to one embodiment of this utility model, the poloidal and in-plane magnetic synchronous detection device further includes a beam decomposition component. The detection light emitted by the light source is decomposed into a first sub-detection light and a second sub-detection light by the beam decomposition component. The first sub-detection light and the second sub-detection light are symmetrically incident on the test object along the normal of the test surface.

[0013] According to one embodiment of this utility model, the focal plane of the objective lens coincides with the surface to be measured of the object being measured.

[0014] According to one embodiment of this utility model, the axis of symmetry of the detection light incident on the test object passes through the back focal point of the objective lens.

[0015] This invention has at least the following advantages: it can achieve synchronous detection of the polar and in-plane magnetism of the object under test using the same detection light, without the need to switch optical paths, making detection convenient and ensuring that there is no misalignment between the obtained polar and in-plane magnetism; on the other hand, it can enhance the intensity of the longitudinal magneto-optic Kerr signal, reduce noise, and improve the detection accuracy of in-plane magnetism. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of one embodiment of the present invention.

[0017] Figure 2This is a schematic diagram of the overall structure of another embodiment of the present invention.

[0018] Figure 3 This is a schematic diagram of one embodiment of the sensor involved in this utility model.

[0019] Figure 4 This is a schematic diagram of another embodiment of the sensor involved in this utility model.

[0020] In the figure: 1, light source; 11, first sub-light source; 12, second sub-light source; 2, polarizer; 3, beam splitter; 4, objective lens; 5, object under test; 6, analyzer; 7, sensor; 71, photosensitive area; 81, in-plane excitation device; 82, poloidal excitation device. Detailed Implementation

[0021] To make the objectives and features of this utility model clearer and easier to understand, the specific embodiments of this utility model will be further described below with reference to the accompanying drawings. It should be noted that the drawings are all in a very simplified form and use non-precise ratios, and are only used to facilitate and clearly assist in illustrating the embodiments of this utility model.

[0022] This invention provides a device for simultaneous detection of polar and in-plane magnetism, which utilizes the magneto-optical Kerr effect to detect the polar and in-plane magnetism of the object being tested.

[0023] Light source 1 is used to emit detection light to detect the object 5. Light source 1 can be a laser light source, an LED light source, or other types of light sources, as long as it can emit light and be used for detection.

[0024] The light emitted by the light source 1 passes through the polarizer 2 to form polarized light. The polarizer 2 can be a polarizer, crystal polarizer, optical rotator, dichroic crystal, wire grating polarizer, or Brewster's angle to form polarized light. The specific settings and adjustments can be made as needed.

[0025] The detection light is focused by the objective lens 4 onto the test position of the test object 5. Since the detection light is polarized, the detection light reflected by the test object 5 can be affected by the magnetism of the test position of the test object 5 and the polarization state will change. The magnetism of the test object can be obtained by detecting the change in the polarization state of the detection light.

[0026] The analyzer 6 and the sensor 7 work together to detect the polarization state of the detection light. Specifically, the analyzer 6 can be a polarizer. The intensity of the detection light after passing through the analyzer 6 is related to the polarization state of the detection light. The intensity of the detection light can then be detected by the sensor 7 to calculate the polarization state of the detection light, thereby obtaining the magnetism of the measured position of the object 5.

[0027] The detection light emitted from light source 1 passes through polarizer 2, beam splitter 3, and objective lens 4, and is symmetrically incident on the test object 5 along the normal to the surface being tested. It should be noted that the symmetry of the detection light incident on the test object along the normal to the surface means that the incident direction of the light is symmetrical along the normal. In some cases, the incident direction of the detection light incident on the test object 5 is symmetrical along the normal to the surface being tested, but the optical path is not perfectly symmetrical.

[0028] Since the detection light incident on the test object 5 is symmetrical along the normal to the surface being tested, the detection light reflected from the test position of the test object 5 is also symmetrical along the normal to the surface being tested. More specifically, for the two sub-beams of the detection light symmetrical along the normal to the surface being tested, the propagation path of one of the sub-beams incident on the test object 5 coincides with and is opposite in direction to the propagation path of the other sub-beam incident on the test object 5. Correspondingly, the detection light incident on the objective lens 4 is symmetrical along the axis of symmetry of the detection light, and the detection light after being deflected by the objective lens 4 is symmetrical along the normal direction of the surface being tested on the test object 5. The parts of the detection light symmetrical along the normal direction of the surface being tested on the test object 5 have the characteristic that their propagation paths coincide and are opposite in direction. Therefore, the parts of the detection light reflected by the test object 5 that are symmetrical along their axis of symmetry have the characteristic that they are incident on the test object 5 in opposite directions and have the same angle of incidence.

[0029] After being reflected by the object under test 5, the detection light passes through the objective lens 4 and the analyzer 6 before entering the sensor 7. The sensor 7 can generate a matching electrical signal based on the intensity of the received light. By reading the electrical signal of the sensor 7, the intensity of the detection light illuminating the sensor 7 can be obtained. Combined with the characteristic of the analyzer 6 to convert the polarization state of the detection light into a light intensity characteristic, the influence of the magneto-optical Kerr effect on the polarization state of the detection light can be analyzed, and thus the magnetism of the measured position of the object under test 5 can be calculated.

[0030] The sensor 7 includes at least two photosensitive areas 71, which are symmetrically arranged along the axis of symmetry L1 of the detection light. Accordingly, the detection light can be symmetrically irradiated onto at least two photosensitive areas 71, and the sensor 7 can output a corresponding signal based on the light intensity of the detection light received by the corresponding photosensitive area 71. Since the symmetrical portions of the detection light reflected from the object 5 along its axis of symmetry L1 have the characteristic of incident on the object 5 in opposite directions at the same angle, and since the symmetrical detection light along the axis of symmetry L1 irradiates different photosensitive areas 71, the symmetrical photosensitive areas 71 correspond to the detection light incident on the object 5 in opposite directions at the same angle.

[0031] Since the detection light incident on the test object 5 is symmetrical along the normal to the test surface, all detection lights except those incident along the normal to the test surface have corresponding non-zero incident angles, and the corresponding detection lights carry at least a poloidal magneto-optical Kerr signal and a longitudinal magneto-optical Kerr signal. Corresponding to the illumination area of ​​the detection light on the photosensitive area 71 of the sensor 7, except for the light along the symmetry axis L1 of the detection light, the detection light at other positions carries at least a poloidal magneto-optical Kerr signal and a longitudinal magneto-optical Kerr signal. Since there is at least a photosensitive area 71 symmetrical along the symmetry axis L1 of the detection light, the detection light received by the photosensitive area 71 contains at least a poloidal magneto-optical Kerr signal and a longitudinal magneto-optical Kerr signal. Therefore, the poloidal magneto-optical Kerr signal and the longitudinal magneto-optical Kerr signal can be analyzed through the signal from the photosensitive area 71 of the photoelectric sensor 7, thereby analyzing the poloidal magnetism and in-plane magnetism of the test object.

[0032] When calculating the poloidal magneto-optical Kerr effect to analyze poloidal magnetism, the detection light can be treated as a whole, considered as polarized light perpendicularly incident on the test object 5. By treating the signals of the photosensitive regions 71 symmetrical along the axis of symmetry L1 of the detection light as a whole, the poloidal magnetism of the test surface of the test object 5 can be analyzed. When calculating the longitudinal magneto-optical Kerr effect to analyze in-plane magnetism, the detection light can be divided into several parts. Accordingly, the detection light received by one of the photosensitive regions 71 can be considered as detection light obliquely incident on the test object 5. The detection light received by the symmetrical photosensitive regions 71 are incident on the test object 5 in directions symmetrical along the normal of the test surface. The intensity changes of the detection light symmetrically incident on the test object 5 along the normal of the test surface are different under the same magneto-optical Kerr effect. In this case, the signals of the symmetrical photosensitive regions 71 can be processed separately to amplify the influence of the longitudinal magneto-optical Kerr signal on the light intensity, thereby enhancing the intensity of the longitudinal magneto-optical Kerr signal and thus obtaining the in-plane magnetism of the test surface of the test object 5.

[0033] Based on the detection device provided by this utility model, the polar and in-plane magnetism of the test object 5 can be simultaneously detected using the same detection light without switching the optical path. The detection is convenient and there is no misalignment between the obtained polar and in-plane magnetism. On the other hand, it can enhance the intensity of the longitudinal magneto-optic Kerr signal, reduce noise, and improve the detection accuracy of in-plane magnetism.

[0034] Please see Figure 3As one feasible implementation, the sensor 7 includes two photosensitive areas 71. By configuring the optical elements in the detection device provided by this invention, and / or the position and angle of the object 5 to be measured, the detection light can be symmetrically irradiated onto the two photosensitive areas. Based on this, the photosensitive areas A and B can be treated as a whole to analyze the poloidal magnetism of the object 5; the difference in light intensity between the photosensitive areas A and B can be analyzed to analyze the in-plane magnetism of the object 5.

[0035] Please see Figure 4 As another feasible implementation, the sensor 7 includes four photosensitive areas 71, and detection light is symmetrically irradiated onto the four photosensitive areas 71. Specifically, the four photosensitive areas 71 can be divided into symmetrical groups. For example, photosensitive areas A and B can be grouped as the first group, and photosensitive areas C and D as the second group, with the first and second groups being symmetrical to each other; alternatively, photosensitive areas A and D can be grouped as the first group, and photosensitive areas B and C as the second group, with the first and second groups being symmetrical to each other. Based on this, at least photosensitive areas A, B, C, and D can be treated as a whole to analyze the poloidal magnetism of the test object 5; the difference in light intensity received by the first and second groups of photosensitive areas symmetrical along a first direction can be analyzed to analyze the in-plane magnetism of the test object 5 along a certain direction; and the difference in light intensity received by the first and second groups of photosensitive areas symmetrical along a second direction can be analyzed to analyze the in-plane magnetism of the test object 5 along another direction.

[0036] The sensor 7 may further include a greater number of photosensitive areas 71, as long as at least two photosensitive areas 71 are symmetrically arranged along the axis of symmetry L1 of the detection light. With the aforementioned arrangement of this utility model, the detection light can symmetrically illuminate the symmetrical photosensitive areas 71 for analyzing the in-plane and polar magnetic properties of the test object 5.

[0037] Please see Figure 2 This illustrates another feasible embodiment of the present invention, wherein the light source includes a first sub-light source 11 that emits a first sub-detection light and a second sub-light source 12 that emits a second sub-detection light, and the first sub-detection light and the second sub-detection light are symmetrically incident on the test object 5 along the normal of the test surface of the test object 5.

[0038] In some cases, the first sub-light source 11 and the second sub-light source 12 can be further configured so that the first sub-detection light emitted by the first sub-light source 11 and the second sub-detection light emitted by the second sub-light source 12 have the same light intensity, thereby further improving the detection accuracy of the object under test 5. Specifically, the same light intensity here refers to the fact that the light intensity of the first sub-detection light and the second sub-detection light before incident on the object under test 5 is roughly the same, not that the light intensity incident on the sensor 7 is roughly the same; more specifically, it refers to the fact that the light intensity of the first sub-detection light and the second sub-detection light incident on the object under test 5 after exiting from the objective lens 4 is roughly the same.

[0039] In some cases, the poloidal and in-plane magnetic synchronous detection device provided by this utility model further includes a beam splitting component. The detection light emitted by the light source 1 is split into a first sub-detection light and a second sub-detection light by the beam splitting component. The first sub-detection light and the second sub-detection light are symmetrically incident on the test object 5 along the normal of the test surface. For the beam splitting component, at least a number of reflectors can be set to split the detection light. Furthermore, in some cases, the optical path can be configured so that the light intensity of the first sub-detection light and the second sub-detection light before incident on the test object 5 is approximately the same.

[0040] Please see Figure 1 , Figure 2 The poloidal and in-plane magnetic synchronous detection device provided by this utility model also includes a magnetic field generating device, which is configured to generate a magnetic field at the test position of the test object 5.

[0041] Please see Figure 1 , Figure 2 The magnetic field generating device may include at least one of a poloidal excitation device 82 and an in-plane excitation device 81. The poloidal excitation device 82 is configured to generate a magnetic field in a direction perpendicular to the measured surface of the object 5, and the in-plane excitation device 81 is configured to generate a magnetic field in a direction parallel to the measured surface of the object 5.

[0042] The specific form of the magnetic field generating device can be an electromagnet, an excitation coil, or a combination of an electromagnet and an excitation coil, as long as it can generate a preset magnetic field at the measured position of the object being measured 5.

[0043] When a magnetic field generating device is provided, at least one of the magnitude and direction of the magnetic field near the test position of the test object 5 can be adjusted by the magnetic field generating device, thereby changing the magnetism of the test position of the test object 5, so as to analyze the magnetic properties of the test object 5.

[0044] As a feasible implementation, the focal plane of the objective lens 4 can be aligned with the surface to be measured of the object 5, so that the detection light can be focused on the measured position of the object 5. Furthermore, the optical path can be further configured such that the axis of symmetry L1 of the detection light incident on the object 5 passes at least through the back focal point of the objective lens 4, so that the detection light incident on the objective lens 4 and subsequently on the object 5 coincides with the detection light reflected from the object 5 and exiting through the objective lens 4.

[0045] In some cases, the poloidal and in-plane magnetic synchronous detection device provided by this utility model also includes a data processor, which is at least communicatively connected to the sensor 7 so as to process the data of the sensor 7 through the data processor.

[0046] The basic principles, main features, and advantages of this utility model have been shown and described above. Therefore, the above description is only an embodiment of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are only the principles of this utility model. Without departing from the spirit and scope of this utility model, this utility model also includes various equivalent changes and modifications, all of which will fall within the scope of this utility model as claimed.

Claims

1. A poloidal, in-plane magnetic synchronous detection device, characterized in that: It includes a light source, polarizer, beam splitter, objective lens, analyzer, and sensor. The detection light emitted by the light source passes through the polarizer, beam splitter, and objective lens and is symmetrically incident on the test object along the normal of the test surface. The detection light reflected by the test object passes through the objective lens, beam splitter, and analyzer and is incident on the sensor. The sensor includes at least two photosensitive areas, which are symmetrically arranged along the axis of symmetry of the detection light.

2. The poloidal and in-plane magnetic synchronous detection device as described in claim 1, characterized in that: The sensor includes two photosensitive areas, and detection light is symmetrically irradiated onto the two photosensitive areas.

3. The poloidal and in-plane magnetic synchronous detection device as described in claim 1, characterized in that: The sensor includes four photosensitive areas, and detection light is symmetrically irradiated onto the four photosensitive areas.

4. The poloidal and in-plane magnetic synchronous detection device as described in claim 1, characterized in that: The light source includes a first sub-light source that emits a first sub-detection light and a second sub-light source that emits a second sub-detection light. The first sub-detection light and the second sub-detection light are symmetrically incident on the test object along the normal of the test surface.

5. The poloidal and in-plane magnetic synchronous detection device as described in claim 4, characterized in that: The first sub-detection light emitted by the first sub-source and the second sub-detection light emitted by the second sub-source have the same intensity.

6. The poloidal and in-plane magnetic synchronous detection device as described in claim 1, characterized in that: The polar and in-plane magnetic synchronous detection device also includes a magnetic field generator, which is configured to generate a magnetic field at the measured position of the object being measured.

7. The poloidal and in-plane magnetic synchronous detection device as described in claim 6, characterized in that: The magnetic field generating device includes at least one of a poloidal excitation device and an in-plane excitation device. The poloidal excitation device is configured to generate a magnetic field in a direction perpendicular to the measured surface of the object being measured, and the in-plane excitation device is configured to generate a magnetic field in a direction parallel to the measured surface of the object being measured.

8. The poloidal and in-plane magnetic synchronous detection device as described in claim 1, characterized in that: The poloidal and in-plane magnetic synchronous detection device also includes a beam decomposition component. The detection light emitted by the light source is decomposed into a first sub-detection light and a second sub-detection light by the beam decomposition component. The first sub-detection light and the second sub-detection light are symmetrically incident on the test object along the normal of the test surface.

9. The poloidal and in-plane magnetic synchronous detection device as described in claim 1, characterized in that: The focal plane of the objective lens coincides with the surface of the object being measured.

10. The poloidal and in-plane magnetic synchronous detection device as described in claim 9, characterized in that: The axis of symmetry of the detection light incident on the object passes through the back focal point of the objective lens.

Images