A pattern ground shielding structure, an inductance device and an imaging device

Abstract

The application discloses a pattern ground shielding structure, an inductance device and an imaging device. The pattern ground shielding structure is applied to the inductance device, and the inductance device is used in the imaging device. The pattern ground shielding structure comprises a substrate and at least one shielding unit. The shielding unit is arranged on the substrate. Each shielding unit comprises a first shielding unit and a second shielding unit. The first shielding unit comprises a plurality of conductive strips arranged at intervals along a first direction. The second shielding unit comprises a plurality of conductive strips arranged at intervals along a second direction. The second direction intersects the first direction. The orthogonal projection of each conductive strip on the substrate is a rectangle. The pattern ground shielding structure comprises the conductive strips arranged at intervals. Capacitive coupling can be weakened, the signal-to-noise ratio of a receiving chain can be improved, radio frequency power absorption can be reduced, and thermal safety risks can be reduced. The pattern ground shielding structure can suppress eddy current paths and avoid additional losses introduced by the shielding structure itself and interference with a main magnetic field.

Description

Technical Field

[0001] This application relates to the field of electromagnetic shielding technology, and in particular to a patterned grounding shielding structure, an inductive device, and an imaging device. Background Technology

[0002] In fields such as magnetic resonance imaging (MRI), to improve the signal-to-noise ratio (SNR) of imaging in specific areas (such as the abdomen), many solutions employ wired surface coil arrays for signal acquisition. However, these coils must be placed close to or around the target area, resulting in strong capacitive coupling between the RF coil and the human tissue. This capacitive coupling generates an additional RF electric field within the body, leading to increased dielectric loss and noise, thus reducing the SNR. It also increases the absorption rate of certain areas, posing thermal safety risks. Summary of the Invention

[0003] This application provides a patterned grounding shielding structure, an inductor, and an imaging device to solve the technical problems of capacitive coupling and thermal safety between radio frequency coils and the human body in related technologies.

[0004] To address the aforementioned technical problems, this application provides a patterned grounding shielding structure applied to an inductor device. The patterned grounding shielding structure includes a substrate and at least one shielding unit.

[0005] The shielding unit is disposed on the substrate. Each shielding unit includes a first shielding unit and a second shielding unit. The first shielding unit includes a plurality of conductive strips spaced apart along a first direction. The second shielding unit includes a plurality of conductive strips spaced apart along a second direction. The second direction intersects the first direction, and the orthographic projection of each conductive strip onto the substrate is a rectangle.

[0006] In some embodiments, the number of shielding units is greater than or equal to 2, and at least two shielding units are stacked.

[0007] In some embodiments, each shielding unit includes two first shielding units and two second shielding units, the two first shielding units are arranged at intervals along a second direction, the two second shielding units are arranged at intervals along a first direction, and the two first shielding units and the two second shielding units enclose a central opening.

[0008] In some embodiments, the orthographic projection of the central opening onto the base is rectangular.

[0009] In some embodiments, each conductive strip in the first shielding unit has the same length, and each conductive strip in the second shielding unit has the same length.

[0010] In some embodiments, the length of the conductive strip in the first shielding unit is the same as the length of the conductive strip in the second shielding unit.

[0011] In some embodiments, the first shielding unit and the second shielding unit are arranged at an interval.

[0012] To address the aforementioned technical problems, this application also provides an inductor for use in an imaging device. The imaging device includes the inductor and a detection position. The inductor includes a radio frequency coil and the aforementioned patterned grounding shield structure.

[0013] The radio frequency coil is set to correspond to the detection position; the patterned grounding shielding structure is set between the radio frequency coil and the detection position.

[0014] In some embodiments, the vertical distance between the patterned ground shield structure and the detection position is 1 mm; the vertical distance between the patterned ground shield structure and the radio frequency coil is 5 mm.

[0015] In some embodiments, the length of the conductive strip in the patterned grounding shield structure is less than half the wavelength corresponding to the operating frequency of the RF coil.

[0016] To address the aforementioned technical problems, this application also provides an imaging device, which includes the aforementioned inductor and detection position.

[0017] Unlike existing technologies, the beneficial effects of this application are as follows: The patterned grounding shielding structure provided by this application includes spaced conductive strips. On the one hand, it can weaken capacitive coupling without affecting the reception of magnetic resonance signals, thereby effectively improving the signal-to-noise ratio of the receiving link. On the other hand, it can reduce the RF power absorption rate per unit mass, thereby reducing thermal safety risks while ensuring image quality. Furthermore, it can effectively suppress the formation of eddy current paths, avoiding additional losses introduced by the shielding structure itself and its interference with the main magnetic field. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 This is a schematic diagram of the patterned grounding shield structure provided in some embodiments of this application; Figure 2 These are schematic diagrams of the inductor and imaging devices provided in some embodiments of this application; Figure 3 This is a schematic diagram of the simulation curve of the normalized magnetic field strength |B| at the center of the square ring resonator provided in some embodiments of this application; Figure 4This is a schematic diagram of the simulation curve of normalized power loss in the human body equivalent model provided in some embodiments of this application.

[0019] Figure label: 10. Patterned grounding shielding structure; 11. Substrate; 12. Shielding unit; 121. First shielding unit; 122. Second shielding unit; 20. Inductor; 21. Radio frequency coil; 30. Imaging equipment; 31. Detection position; X1, First direction; X2, Second direction; O, Central opening. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0021] It should be noted that if the embodiments of this application involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0022] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0023] According to some embodiments of this application, please refer to Figure 1 This application provides a patterned grounding shield structure 10, which is applied to an inductor device 20. The patterned grounding shield structure 10 includes a substrate 11 and at least one shielding unit 12.

[0024] The conductive strips in the shielding unit 12 are arranged periodically. In some embodiments, the shielding unit 12 is disposed on the substrate 11. Each shielding unit 12 includes a first shielding unit 121 and a second shielding unit 122. The first shielding unit 121 includes a plurality of conductive strips spaced apart along a first direction X1. The second shielding unit 122 includes a plurality of conductive strips spaced apart along a second direction X2. The second direction X2 intersects the first direction X1, and the orthographic projection of each conductive strip onto the substrate 11 is rectangular.

[0025] In some embodiments, the length of the conductive strip in the shielding unit 12 is less than half the wavelength of the electromagnetic wave corresponding to the patterned grounding shielding structure 10 when it is working, so as to avoid resonance and ensure shielding performance.

[0026] In some embodiments, the number of first shielding units 121 and second shielding units 122 in each shielding unit 12 is determined according to the actual situation. For example, each shielding unit 12 includes two first shielding units 121 and two second shielding units 122.

[0027] In some embodiments, the number of conductive strips in each first shielding unit 121 is determined according to actual conditions; for example, the number of conductive strips in the first shielding unit 121 is greater than or equal to 12. The number of conductive strips in each second shielding unit 122 is determined according to actual conditions; for example, the number of conductive strips in the second shielding unit 122 is greater than or equal to 12. In some embodiments, the number of conductive strips in the first shielding unit 121 and the second shielding unit 122 is the same.

[0028] In some embodiments, the gap between any two conductive strips in the first shielding unit 121 is the same, that is, the conductive strips in the first shielding unit 121 are arranged at equal intervals; the gap between any two conductive strips in the second shielding unit 122 is the same, that is, the conductive strips in the second shielding unit 122 are arranged at equal intervals. In some embodiments, the gap between any two conductive strips in the first shielding unit 121 is the same as the gap between any two conductive strips in the second shielding unit 122.

[0029] In some embodiments, the substrate 11 may be a PCB substrate, an air gap, or other high-impedance insulating material. The shielding unit 12 is made of a conductive material; specifically, the conductive strips are made of conductive materials such as copper, aluminum, silver, or gold. The orthographic projection of each conductive strip onto the substrate 11 is rectangular, which may be a square or a rectangle, depending on the specific circumstances.

[0030] In some embodiments, the angle between the first direction X1 and the second direction X2 is an acute angle or a right angle, such as 30°, 45°, 60°, or 90°. In some embodiments, the first direction X1 is parallel to the width direction of the conductive strip in the first shielding unit 121, and the second direction X2 is parallel to the width direction of the conductive strip in the second shielding unit 122.

[0031] In some embodiments, each conductive strip in the first shielding unit 121 has the same length, and each conductive strip in the second shielding unit 122 has the same length. In other embodiments, each conductive strip in the first shielding unit 121 has a different length, and each conductive strip in the second shielding unit 122 has a different length.

[0032] In some embodiments, the width of each conductive strip in the first shielding unit 121 is the same, and the width of each conductive strip in the second shielding unit 122 is the same. In other embodiments, the width of each conductive strip in the first shielding unit 121 is different, and the width of each conductive strip in the second shielding unit 122 is different.

[0033] In some embodiments, the length of the conductive strip in the first shielding unit 121 is the same as the length of the conductive strip in the second shielding unit 122. In other embodiments, the length of the conductive strip in the first shielding unit 121 is different from the length of the conductive strip in the second shielding unit 122.

[0034] In some embodiments, the width of the conductive strip in the first shielding unit 121 is the same as the width of the conductive strip in the second shielding unit 122. In other embodiments, the width of the conductive strip in the first shielding unit 121 is different from the width of the conductive strip in the second shielding unit 122.

[0035] In some embodiments, the length and width of the conductive strip in the first shielding unit 121 are the same as the length and width of the conductive strip in the second shielding unit 122. For example, the length of the conductive strip is 19.6 mm and the width of the conductive strip is 3 mm.

[0036] In some embodiments, the number of shielding units 12 is greater than or equal to two, such as two, three, or four, with at least two shielding units 12 stacked. The stacking directions of the multiple shielding units 12 are perpendicular to the first direction X1 and the second direction X2, respectively. It can be understood that when multiple shielding units 12 are present, all shielding units 12 are stacked, or some shielding units 12 are stacked and some are spaced apart along the lateral direction, which is parallel to the first direction X1 and the second direction X2, and parallel to the plane defined by the first direction X1 and the second direction X2. Multiple shielding units 12 with the same or different parameters stacked longitudinally can constitute a multi-layer composite shielding structure.

[0037] In some embodiments, see Figure 1 Each shielding unit 12 includes two first shielding units 121 and two second shielding units 122. The two first shielding units 121 are arranged at intervals along the second direction X2, and the two second shielding units 122 are arranged at intervals along the first direction X1. The two first shielding units 121 and the two second shielding units 122 enclose a central opening O.

[0038] In some embodiments, the orthographic projection of the central opening O onto the base 11 is a rectangle, parallelogram, trapezoid, rhombus, or other shape, depending on the specific circumstances.

[0039] In some embodiments, the first shielding unit 121 is connected to the second shielding unit 122, or the first shielding unit 121 and the second shielding unit 122 are spaced apart. When the first shielding unit 121 and the second shielding unit 122 are connected, the central opening O enclosed by the two is a closed opening; when the first shielding unit 121 and the second shielding unit 122 are spaced apart, the central opening O enclosed by the two is a non-closed opening.

[0040] In some embodiments, the shielding unit 12 includes a first conductive strip, which corresponds one-to-one with the first shielding unit 121. Each first conductive strip is used to connect one end of all the conductive strips in a first shielding unit 121 that faces the central opening O.

[0041] In some embodiments, the shielding unit 12 includes a second conductive strip, which corresponds one-to-one with the second shielding unit 122. Each second conductive strip is used to connect one end of all the conductive strips in a second shielding unit 122 toward the central opening O.

[0042] In some embodiments, the shielding unit 12 further includes a third conductive strip, each of which is used to connect adjacent first shielding units 121 and second shielding units 122.

[0043] In some embodiments, the ends of all conductive strips in the first shielding unit 121 facing the central opening O are connected, and the ends of all conductive strips in the second shielding unit 122 facing the central opening O are connected, and the ends of the conductive strips in the first shielding unit 121 facing the central opening O are connected to the ends of the conductive strips in the second shielding unit 122 facing the central opening O.

[0044] According to some embodiments of this application, please refer to Figures 2-4This application also provides an inductor 20 for use in an imaging device 30, which may be a magnetic resonance imaging device. The imaging device 30 includes the inductor 20 and a detection position 31. The inductor 20 includes a radio frequency coil 21 and a patterned ground shielding structure 10 as described in any of the above embodiments. The radio frequency coil 21 and the detection position 31 are correspondingly arranged; the patterned ground shielding structure 10 is disposed between the radio frequency coil 21 and the detection position 31.

[0045] A patterned grounding shielding structure 10 is disposed between the RF coil 21 and the detection position 31, which can achieve electric field isolation between the RF coil 21 and the detection position 31. When an alternating current flows through the RF coil 21, according to Faraday's law of electromagnetic induction, the metal shielding structure will generate strong eddy currents. These eddy currents will cause the shielding structure to heat up violently and thus suffer thermal damage. Furthermore, the equivalent series resistance of the RF coil 21 will increase sharply, resulting in a sharp drop in the Q value (quality factor) and a shift in the resonant frequency. Based on this, the shielding structure needs to be patterned, for example, etched into a grid, a spiral groove, or a comb-like structure (the patterned grounding shielding structure 10 in any of the above embodiments is a comb-like structure), to cut off the loop path of the eddy currents, so that the induced electromotive force cannot form a large loop current, thereby allowing the magnetic field to pass through with almost no attenuation, only providing electrostatic shielding for the electric field. Furthermore, the patterned grounding shielding structure 10 of this application can block electric field coupling (reduce distributed capacitance) without affecting magnetic field penetration (keeping eddy current loss to a minimum).

[0046] In some embodiments, the stacking direction of the patterned ground shield structure 10, the RF coil 21, and the detection position 31 is perpendicular to the plane formed by the first direction X1 and the second direction X2. In some embodiments, the vertical distance between the patterned ground shield structure 10 and the detection position 31 is less than the vertical distance between the patterned ground shield structure 10 and the RF coil 21. For example, the vertical distance between the patterned ground shield structure 10 and the detection position 31 is 1 mm; the vertical distance between the patterned ground shield structure 10 and the RF coil 21 is 5 mm.

[0047] In some embodiments, the current in the RF coil 21 on the patterned ground shield structure 10 is as follows Figure 1 As shown, the flow is clockwise.

[0048] In some embodiments, the length of the conductive strip in the patterned grounding shield structure 10 is less than half the wavelength corresponding to the operating frequency of the RF coil 21. In practical applications such as magnetic resonance imaging, the human body is positioned corresponding to the detection position 31. To ensure effective suppression of the electric field, the width and arrangement period of the conductive strip should be much smaller than the operating wavelength. The length of the conductive strip should be greater than its width and arrangement period to cover the main area of ​​influence of the electric field generated by the RF coil 21 on human tissue. Simultaneously, to avoid exciting resonance in the RF band and interfering with the intrinsic performance of the RF coil 21, the length of the conductive strip must be strictly limited to within half a wavelength. In one application scenario, the arrangement period of the conductive strip is 4 mm, the width is 3 mm, and the length is 19.6 mm.

[0049] In some embodiments, the radio frequency coil 21 includes a ring resonator.

[0050] In the simulation experiment, the RF coil 21 uses a square ring resonator with a side length of 82mm and a line width of 5mm, and the operating frequency is the typical Larmor precession frequency of MRI (Magnetic Resonance Imaging). To simulate the electromagnetic load effect of human tissue, a water phantom with dielectric properties equivalent to human muscle tissue (εr=40, σ=0.7S / m) is placed at the detection position 31 above the resonator. Between the square ring resonator and the water phantom, a patterned grounding shielding structure 10 of any of the above embodiments is inserted. Taking a conductive strip arrangement period of 4mm, a conductive strip width of 3mm, a conductive strip length of 19.6mm, a vertical distance of 1mm between the patterned grounding shielding structure 10 and the detection position 31, and a vertical distance of 5mm between the patterned grounding shielding structure 10 and the RF coil 21 as an example, the normalized magnetic field strength |B| at the center of the square ring resonator is simulated. The corresponding simulation results can be found in [reference needed]. Figure 3 The normalized power loss in the simulated human body equivalent model can be found in the simulation results. Figure 4 Simulation results show that, compared to the unshielded condition, the distribution of the radio frequency magnetic field strength generated by the radio frequency coil 21 remains essentially unchanged (i.e., virtually no attenuation) after inserting the patterned grounding shielding structure 10. Simultaneously, the radio frequency loss within the human body equivalent model (i.e., the water model) is reduced by approximately 4%, verifying that the patterned grounding shielding structure 10 can suppress parasitic electric field coupling and reduce human body dielectric loss without damaging the performance of the imaging device 30.

[0051] According to some embodiments of this application, please refer to Figure 2 This application also provides an imaging device 30, which includes the inductor 20 and the detection position 31 of any of the above embodiments.

[0052] Taking magnetic resonance imaging (MRI) technology as an example, radio frequency (RF) coils are one of the core components that determine the signal-to-noise ratio and image quality. For imaging of deep or specific anatomical sites such as the abdomen and spine, wired surface coil arrays are typically attached to the patient's body surface in clinical practice to enhance the reception of local radio frequency signals.

[0053] However, while receiving magnetic resonance signals, surface-mount coil arrays (SMOs) exhibit strong capacitive coupling between their conductor structure and adjacent human tissue. Due to the excellent conductivity and high dielectric constant of human tissue, this coupling effect induces an additional radio frequency (RF) electric field within the body. This additional electric field not only causes significant dielectric loss (i.e., RF loss) in the tissue, increasing RF energy deposition, but also exacerbates the coupling of tissue thermal noise into the receiving circuit. This additional noise caused by coupling cannot be effectively eliminated by conventional signal averaging or filtering methods, directly leading to a decrease in the signal-to-noise ratio of the receiving link, thus limiting the acquisition of high-resolution, high-contrast images.

[0054] The increased radiofrequency electric field intensity in vivo due to capacitive coupling directly increases the radiofrequency power absorption rate per unit mass of tissue. In large-area or deep imaging scenarios such as the abdomen, to ensure sufficient penetration depth and image quality, it is often necessary to improve the uniformity of the radiofrequency excitation field or increase the radiofrequency pulse energy of the scanning sequence. However, this further exacerbates the increase in local radiofrequency power absorption rate. When the radiofrequency power absorption rate exceeds the standard safety limits, it will cause abnormal heating of local tissues, leading to thermal safety issues and potentially even harming the patient in severe cases. This forces clinical practice to restrict the use of certain high-energy scanning sequences or extend the cooling time between scans, sacrificing imaging efficiency and the richness of diagnostic information.

[0055] To address the aforementioned issues, the patterned grounding shielding structure 10, inductor 20, and imaging device 30 provided in this application effectively suppress harmful electric field coupling between the MRI surface coil and human tissue without physical contact. This reduces radio frequency loss and noise while ensuring thermal safety, improving the convenience of clinical use and patient comfort, and further enhancing the signal-to-noise ratio. Furthermore, compared to traditional continuous conductor shielding layers, the patterned grounding shielding structure 10 of this application can effectively suppress the formation of eddy current paths, avoiding additional losses introduced by the shielding structure itself and its interference with the uniformity of the main magnetic field.

[0056] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A patterned grounding shield structure, applied to an inductive device, characterized in that, The patterned grounding shield structure includes: Base; At least one shielding unit is disposed on the substrate. Each shielding unit includes a first shielding unit and a second shielding unit. The first shielding unit includes a plurality of conductive strips spaced apart along a first direction. The second shielding unit includes a plurality of conductive strips spaced apart along a second direction. The second direction intersects the first direction, and the orthographic projection of each conductive strip on the substrate is rectangular.

2. The patterned grounding shielding structure according to claim 1, characterized in that, The number of shielding units is greater than or equal to 2, and at least two shielding units are stacked.

3. The patterned grounding shielding structure according to claim 1, characterized in that, Each of the shielding units includes two first shielding units and two second shielding units. The two first shielding units are arranged at intervals along the second direction, and the two second shielding units are arranged at intervals along the first direction. The two first shielding units and the two second shielding units enclose a central opening.

4. The patterned grounding shielding structure according to claim 3, characterized in that, The central opening has a rectangular projection onto the base.

5. The patterned grounding shielding structure according to any one of claims 1-4, characterized in that, The conductive strips in the first shielding unit are of the same length, and the conductive strips in the second shielding unit are of the same length.

6. The patterned grounding shielding structure according to claim 5, characterized in that, The length of the conductive strip in the first shielding unit is the same as the length of the conductive strip in the second shielding unit.

7. The patterned grounding shielding structure according to any one of claims 1-4, characterized in that, The first shielding unit and the second shielding unit are arranged at intervals.

8. An inductor device, characterized in that, For use in an imaging device, the imaging device including the inductor and a detection position, the inductor including: An radio frequency coil, wherein the radio frequency coil is configured corresponding to the detection position; The patterned grounding shielding structure according to any one of claims 1-7, wherein the patterned grounding shielding structure is disposed between the radio frequency coil and the detection position.

9. The inductor device according to claim 8, characterized in that, The vertical distance between the patterned grounding shield structure and the detection position is 1mm; The vertical distance between the patterned grounding shield structure and the radio frequency coil is 5mm.

10. The inductor device according to claim 8, characterized in that, In the patterned grounding shield structure, the length of the conductive strip is less than half the wavelength corresponding to the operating frequency of the radio frequency coil.

11. An imaging device, characterized in that, Includes the inductor and detection bit as described in any one of claims 8-10.

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