Stacked common-mode filter

Abstract

The present application discloses a laminated common mode filter, which includes a first magnetic layer and a second magnetic layer, a multi-layered non-magnetic layer arranged between the first magnetic layer and the second magnetic layer, at least part of the non-magnetic layer is provided with an electrode structure, the electrode structure includes a first electrode and a second electrode, the first electrode includes a coil electrode arranged on the non-magnetic layer and a first connecting portion connected to the end of the coil electrode; the second electrode includes a second connecting portion and an extension portion connected to each other, the second connecting portion is laminated and connected to the first connecting portion to form a laminated connection area, and the extension portion is arranged on the non-magnetic layer and extends to the side end surface of the non-magnetic layer. The laminated common mode filter provided in the embodiment of the present application improves the connection strength and structural strength of the connection position of the first electrode and the second electrode by separately manufacturing the first electrode and the second electrode and forming a laminated connection area between the first electrode and the second electrode.

Description

Technical Field

[0001] The present application relates to the technical field of electronic components, and in particular to a laminated common mode filter. Background Art

[0002] With the popularity of smart terminals, consumers have higher and higher requirements for signal transmission of smart terminals. However, smart terminals are susceptible to noise interference during signal transmission. In order to effectively suppress this noise interference, common mode filters are widely used in smart terminals. As a type of filter, the laminated common mode filter has a conductive inner electrode layer laid on the non-magnetic dielectric layer of the laminated common mode filter and sintered simultaneously.

[0003] However, there are some problems in the manufacturing process of the existing laminated common mode filter. Since the inner electrode of the laminated common mode filter is usually made of conductive paste, the inner electrode and the non-magnetic dielectric layer have different shrinkage molding temperature ranges during the co-firing process, which will cause the lead-out part of the inner electrode to be easily pulled by the shrinkage stress generated by sintering and break, resulting in an open circuit in the lead-out part of the inner electrode of the manufactured laminated common mode filter. Summary of the invention

[0004] An embodiment of the present application discloses a laminated common mode filter, which includes a plurality of non-magnetic layers stacked together, and an electrode structure is formed on at least part of the non-magnetic layers. The electrode structure can improve the cracking phenomenon of the lead-out part of the internal electrode in the laminated common mode filter due to shrinkage stress, thereby improving the yield rate of the laminated common mode filter.

[0005] In order to achieve the above-mentioned objectives, in a first aspect, an embodiment of the present application discloses a laminated common mode filter, which includes a first magnetic layer and a second magnetic layer, a multi-layer stacked non-magnetic layer, which is arranged between the first magnetic layer and the second magnetic layer, and at least part of the non-magnetic layer is provided with an electrode structure, the electrode structure includes a first electrode and a second electrode, the first electrode includes a coil electrode arranged on the non-magnetic layer and a first connecting portion connected to the end of the coil electrode; the second electrode includes a second connecting portion and an extension portion connected to each other, the second connecting portion is stacked and connected to the first connecting portion to form a stacked connection area, and the extension portion is arranged on the non-magnetic layer and extends to the side end surface of the non-magnetic layer.

[0006] As an optional embodiment, the area of ​​the stacked connection region is positively correlated with the first distance from the outer ring electrode in the coil electrode to the side end surface of the non-magnetic layer; or the area of ​​the stacked connection region is positively correlated with the second length of the first connection portion in the first direction of the non-magnetic layer.

[0007] As an optional implementation, along the second direction of the non-magnetic layer, the first length of the stacked connection area is positively correlated with the first distance from the outer ring electrode in the coil electrode to the side end surface of the non-magnetic layer.

[0008] As an optional implementation manner, a first ratio of the first length to the first distance is greater than or equal to 0.2 and less than or equal to 0.77; and / or the first distance is greater than or equal to 60 μm and less than or equal to 120 μm.

[0009] As an optional implementation manner, along the second direction of the non-magnetic layer, the second length of the first connecting portion is greater than the third length of the second connecting portion.

[0010] As an optional implementation, the second ratio of the third length to the second length is greater than or equal to 0.47 and less than or equal to 0.84; and / or the second length is greater than or equal to 80 μm and less than or equal to 140 μm.

[0011] As an optional implementation manner, a second distance between the end of the second connecting portion and the inner circle electrode adjacent to the outer circle electrode of the coil electrode is greater than or equal to 20 μm.

[0012] As an optional embodiment, the first connecting part is arranged in the non-magnetic layer, and the second connecting part is stacked above the first connecting part; or the second connecting part is arranged in the non-magnetic layer, and the first connecting part is stacked above the second connecting part.

[0013] As an optional implementation, along the second direction of the non-magnetic layer, the length product of the first connecting portion is greater than the length of the outer ring electrode in the coil electrode.

[0014] As an optional implementation, the first electrode includes a first conductive metal powder, the second electrode includes a second conductive metal powder, and the mass ratio of the first conductive metal powder to the first electrode is greater than the mass ratio of the second conductive metal powder to the second electrode.

[0015] As an optional embodiment, the laminated common mode filter also includes: a first non-magnetic substrate, arranged on a side of the first magnetic layer away from the multi-layer stacked non-magnetic layer; a second non-magnetic substrate, arranged on a side of the second magnetic layer away from the multi-layer stacked non-magnetic layer.

[0016] Compared with the related art, the laminated common mode filter provided by the embodiment of the present application has at least the following beneficial effects:

[0017] The laminated common mode filter provided in the embodiment of the present application improves the connection strength and structural strength of the connection position of the first electrode and the second electrode by separately manufacturing the first electrode and the second electrode on the non-magnetic layer and forming a laminated connection area between the first electrode and the second electrode, thereby offsetting the stress pulling caused by different shrinkage stresses that the first electrode and the second electrode may be subjected to, as well as the adverse effects caused by factors such as cutting stress that the second electrode may be subjected to during the processing and manufacturing of the laminated common mode filter, avoiding cracking defects caused by the lead-out part of the electrode mechanism, thereby improving the reliability of the laminated common mode filter product. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 One of the structural schematic diagrams of the laminated common mode filter provided in the embodiment of the present application;

[0020] Figure 2 One of the structural schematic diagrams of the electrode structure on the non-magnetic layer in the laminated common mode filter provided in the embodiment of the present application;

[0021] Figure 3 The second structural schematic diagram of the electrode structure on the non-magnetic layer in the laminated common mode filter provided in the embodiment of the present application;

[0022] Figure 4 The third structural schematic diagram of the electrode structure on the non-magnetic layer in the laminated common mode filter provided in the embodiment of the present application;

[0023] Figure 5 A schematic diagram of multiple electrode structures formed during the printing process of the laminated common mode filter provided in an embodiment of the present application;

[0024] Figure 6 One of the performance comparison diagrams of the laminated common mode filter provided in the embodiment of the present application and the laminated common mode filter of the control;

[0025] Figure 7 The second performance comparison diagram of the laminated common mode filter provided by the embodiment of the present application and the laminated common mode filter of the control;

[0026] Figure 8 The third performance comparison diagram of the laminated common mode filter provided by the embodiment of the present application and the laminated common mode filter of the control;

[0027] Fig. 9A fourth performance comparison diagram of the laminated common mode filter provided by the embodiment of the present application and the laminated common mode filter of the control;

[0028] Fig.10 Figure 5 showing the performance comparison between the laminated common mode filter provided in the embodiment of the present application and the laminated common mode filter used as a control;

[0029] Fig.11 This is the second structural schematic diagram of the laminated common mode filter provided in an embodiment of the present application.

[0030] Description of reference numerals:

[0031] 10 electrode structure, 11 first magnetic layer, 12 second magnetic layer, 20 non-magnetic layer, 100 first electrode, 102 coil electrode, 104 outer ring electrode, 106 inner ring electrode, 108 first connecting part, 200 second electrode, 202 second connecting part, 204 extension part, 21 first non-magnetic substrate, 22 second non-magnetic substrate. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0033] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0034] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0035] In addition, the terms "installed", "set", "provided with", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0036] In addition, the terms "first", "second", etc. are mainly used to distinguish different devices, elements or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance and quantity of the indicated devices, elements or components. Unless otherwise specified, "plurality" means two or more.

[0037] Please also read Figures 1 to 11 Specifically, see Figure 1 , Figure 2 and Figure 3 , an embodiment of the present application provides a laminated common mode filter, the laminated common mode filter includes: a first magnetic layer 11, a second magnetic layer 12, and a multi-layer non-magnetic layer 20 arranged between the first magnetic layer 11 and the second magnetic layer 12, at least part of the non-magnetic layer is provided with an electrode structure 10. The electrode structure 10 includes a first electrode 100 and a second electrode 200 connected to the first electrode 100. The first electrode 100 includes a coil electrode 102 arranged on the non-magnetic layer 20 and a first connecting portion 108 connected to the end of the coil electrode 102; the second electrode 200, the second electrode 200 includes a second connecting portion 202 and an extending portion 204, the second connecting portion 202 is stacked and connected with the first connecting portion 108 to form a stacked connection area, and the extending portion 204 is arranged on the non-magnetic layer 20 and extends to the side end surface of the non-magnetic layer 20. In order to clearly show the connection relationship between the first electrode 100 and the second electrode 200, Figure 1 and Figure 4 The first electrode 100 shown in FIG. 1 hides a part of the coil electrode.

[0038] The first magnetic layer 11 and the second magnetic layer 12 are made of magnetic materials, and the first magnetic layer 11 and the second magnetic layer 12 are respectively located at the two ends of the multi-layer stacked non-magnetic layer. Since the first magnetic layer 11, the second magnetic layer 12 and the multi-layer non-magnetic layer 20 need to be co-fired, and since the shrinkage rates of the magnetic material and the non-magnetic material during sintering are inconsistent, the first magnetic layer 11 and the second magnetic layer 12 can limit the shrinkage of the non-magnetic layer 20 to reduce the stress caused by the shrinkage of the non-magnetic layer 20 on the electrode structure 10 arranged thereon.

[0039] like Figure 1As shown, in the multi-layered non-magnetic layers, electrode structures are provided on all non-magnetic layers. In other embodiments, electrode structures can be provided on some non-magnetic layers in the laminated common mode filter to achieve the filtering function of the laminated common mode filter, and electrode structures are not provided on some non-magnetic layers. Exemplarily, such non-magnetic layers without electrode structures can be used to form a gap between the non-magnetic layer with the electrode structure and the first magnetic layer and the second magnetic layer to prevent the electrode structure from being connected to the first magnetic layer and the second magnetic layer when the current in the laminated common mode filter is too large.

[0040] For example, Figure 1 As shown, the non-magnetic layer 20 provided with the electrode structure 10 can be multilayered, and the second electrode 200 in the electrode structure 10 is connected to the first electrode 100 in a stacked manner and extends to the side end surface to be connected to the external electrode, and the external electrode is used to connect the laminated common mode filter with other electrical components. Among them, the electrode structure 10a and the electrode structure 10c are two electrode structures formed by printing and segmentation in pairs, the electrode structure 10a is arranged on the non-magnetic layer 20a, and the electrode structure 10c is arranged on the non-magnetic layer 20c. The second electrode of the electrode structure 10a is connected to the positive external electrode, and the second electrode of the electrode structure 10c is connected to the negative external electrode. The electrode structure 10a is connected to the electrode structure 10c to form a first group of coils.

[0041] Correspondingly, the electrode structure 10b and the electrode structure 10d are two electrode structures formed by symmetrical printing and segmentation. The electrode structure 10b is arranged on the non-magnetic layer 20b, and the electrode structure 10d is arranged on the non-magnetic layer 20d. The second electrode of the electrode structure 10b is connected to the positive external electrode, and the second electrode of the electrode structure 10d is connected to the negative external electrode. The electrode structure 10b is connected to the electrode structure 10d to form a second group of coils.

[0042] Optionally, one or more non-magnetic layers without electrode structures may be provided between the non-magnetic layer 20a and the first magnetic layer 11 , and one or more non-magnetic layers without electrode structures may be provided between the non-magnetic layer 20d and the second magnetic layer 12 .

[0043] The non-magnetic layer 20 can be made of non-magnetic glass, non-magnetic ferrite, ceramic or other non-conductive materials. The inner electrode, that is, the electrode structure 10, is arranged on the non-magnetic layer 20. The electrode structure 10 may include a first electrode 100 and a second electrode 200 that are separately manufactured, and a portion of the second electrode 200 is connected to the tail of the first electrode 100 and a bending structure is formed between the two. The second electrode 200 and the tail of the first electrode 100 are stacked in the Z-axis direction of the laminated common mode filter, and a stacked connection area connected to each other is formed on the tail of the first electrode 100 and the second electrode 200, thereby improving the connection strength and structural strength of the lead-out part of the electrode structure 10 (the tail of the first electrode 100 and the second electrode 200), avoiding the cracking defect of the lead-out part of the electrode structure 10 due to shrinkage stress, and improving the reliability of the laminated common mode filter product.

[0044] Specifically, the first electrode 100 may include a coil electrode 102 and a first connecting portion 108 (ie, the tail portion of the first electrode 100) formed integrally with the coil electrode 102. Figure 4 The coil electrode 102 may be constructed as a racetrack-shaped structure, and the first connecting portion 108 is disposed at the tail of the outermost circle of the coil electrode 102 .

[0045] The second electrode 200 can be an electrode that realizes the lead-out function, and the second electrode 200 includes a second connecting portion 202 and an extension portion 204 integrally formed with the second connecting portion 202. The second connecting portion 202 is stacked and connected with the first connecting portion 108 in the Z-axis direction of the laminated common mode filter, and the area where the two are connected forms the above-mentioned stacked connection area. The extension portion 204 is formed on the surface of the non-magnetic layer 20 and extends to the surface of the side end of the non-magnetic layer 20, so that the second electrode 200 is connected to the external electrode in the laminated common mode filter, thereby introducing the current generated in the first electrode 100 and the second electrode 200 to the external electrode. Please refer to Figure 5 When the electrode structure 10 is printed, it can be symmetrically formed on the non-magnetic layer 20 during the preparation process, and then cut along the symmetry center line on the second electrode 200 to obtain a pair of electrode structures 10, and then sintered. In this process, the second electrode 200 will be affected by the cutting stress.

[0046] The first electrode 100 and the second electrode 200 can be made of conductive paste with different conductive metal contents, so that the shrinkage temperature of the first electrode 100 and the second electrode 200 during the sintering process will be different, and the shrinkage stress generated by the two may not be consistent. The position where the two are connected is easily pulled by different shrinkage stresses and breaks. In addition, since the shrinkage stresses of the electrode structure 10 and the non-magnetic layer 20 during sintering are also different, the stress effect of the first electrode 100 and the second electrode 200 during the sintering process will be aggravated. However, by forming a stacked connection area between the first electrode 100 and the second electrode 200, the connection area and connection strength between the two are further optimized, so that the above-mentioned shrinkage stress difference can be offset, thereby avoiding cracking defects caused by shrinkage stress.

[0047] It can be understood that even if the following factors affect the second electrode 200: the second electrode 200 is bent at a large angle relative to the first electrode 100, the first electrode 100 and the second electrode 200 have different contraction stresses, the contraction stress between the electrode structure 10 as a whole and the non-magnetic layer 20 is different, and the second electrode 200 is subjected to cutting stress during the preparation process, the structural strength of the electrode structure 10 at the lead-out portion can be improved by manufacturing the second electrode 200 and the first electrode 100 separately and connecting them in layers, and the electrode cracking defects that may be caused by the above-mentioned stress influence and structural bending can still be offset.

[0048] It should be noted that the stacked connection area is a region formed by stacking the first connection portion 108 and the second connection portion 202. The stacked connection area can be defined by the shape of the second connection portion 202, and the shape of the stacked connection area specifically depends on the connection position of the first connection portion 108 and the second connection portion 202.

[0049] Thus, in the laminated common mode filter provided by the embodiment of the present application, the electrode structure 10 arranged on the non-magnetic layer 20 includes a first electrode 100 and a second electrode 200 which are separately manufactured and laminated and connected. Since a laminated connection area is formed between the first electrode 100 and the second electrode 200, the connection strength and structural strength of the connection position of the first electrode 100 and the second electrode 200 are improved, thereby offsetting the adverse effects caused by comprehensive factors such as the formation of a bending structure at the connection, the stress pulling caused by different shrinkage stresses on the first electrode 100 and the second electrode 200, the stress pulling of the non-magnetic layer 20 on the electrode structure 10 as a whole, and the cutting stress on the second electrode 200 during the preparation process, thereby avoiding cracking defects in the lead-out part of the electrode structure 10, thereby improving the reliability of the laminated common mode filter product.

[0050] In other embodiments, the area of ​​the stacked connection region is positively correlated with the first distance from the outer ring electrode 104 in the coil electrode 102 to the side end surface of the non-magnetic layer 20; or the area of ​​the stacked connection region is positively correlated with the second length of the first connecting portion 108 in the first direction of the non-magnetic layer 20.

[0051] It should be noted that if the area of ​​the stacked connection region is too small, it is difficult to achieve the effect of improving the connection strength between the first electrode 100 and the second electrode 200. In addition, since the stacked connection region may be formed by the first electrode 100 and the second electrode 200 of different materials, the stacked connection region may be pulled by different stresses during the sintering process to generate cracks. Limiting the area of ​​the stacked connection region within a reasonable range can reduce cracking defects.

[0052] Optionally, see Figure 3 and Figure 4 The first distance H1 from the outer ring electrode 104 of the coil electrode 102 to the side end surface of the non-magnetic layer 20 is usually fixed, and the area of ​​the stacked connection region can be adjusted according to the length value of the first distance H1, so that the first length L1 is within a reasonable ratio range relative to the first distance H1. In this way, the reasonable space between the outer ring electrode 104 of the coil electrode 102 and the side end surface of the non-magnetic layer 20 is fully utilized, the connection strength between the first electrode 100 and the second electrode 200 is improved, and the deformation and cracking of the stacked connection region are avoided.

[0053] Optionally, the first direction of the non-magnetic layer 20 is Figure 3 In the X-axis direction, along the first direction, the second length L2 of the first connecting part 108 is greater than the length of the second connecting part 202, which means that the stacking connection area is limited by the second connecting part 202 and is located in the first connecting part 108, that is, the second length L2 of the first connecting part 108 provides a spatial range in which the stacking connection area can be set, and therefore the area of ​​the stacking connection area is positively correlated with the second length L2 of the first connecting part 108.

[0054] In order to further ensure the connection reliability between the first electrode 100 and the second electrode 200 at the connection position, in other embodiments, along the second direction of the non-magnetic layer 20, that is, along Figure 3 The first length of the stacked connection region is positively correlated with the first distance from the outer ring electrode 104 in the coil electrode 102 to the side end surface of the non-magnetic layer 20 .

[0055] See also Figure 3 The length of the stacked connection area in the Y-axis direction is a first length L1, and the distance from the outer ring electrode 104 in the coil electrode 102 to the side end surface of the non-magnetic layer 20 is a first distance H1.

[0056] It can be understood that if the first length L1 of the stacked connection area is too small, the connection strength between the first electrode 100 and the second electrode 200 will be reduced, and the lead-out portion of the electrode structure 10 is susceptible to cracks due to cutting stress, and the cracking is further aggravated after sintering shrinkage. However, if the first length L1 of the stacked connection area is too large, it may also have adverse effects. For example, during the development or printing process of the conductive paste, due to the adaptability, thixotropy and screen adhesion of the conductive paste to the non-magnetic layer 20, the conductive paste may be spread or deformed. Therefore, if the first length L1 of the stacked connection area is too large, the stacked connection area may be deformed, resulting in a thinning of the thickness of the stacked connection area and the formation of cracks.

[0057] Since the first distance H1 from the outer ring electrode 104 of the coil electrode 102 to the side end surface of the non-magnetic layer 20 is fixed, the first length L1 of the stacked connection area can be adjusted according to the length value of the first distance H1, so that the first length L1 is within a reasonable ratio range relative to the first distance H1. In this way, the reasonable space between the outer ring electrode 104 of the coil electrode 102 and the side end surface of the non-magnetic layer 20 is fully utilized, the connection strength between the first electrode 100 and the second electrode 200 is improved, and the deformation and cracking of the stacked connection area are avoided to a certain extent.

[0058] In this way, by adjusting the first length L1 of the stacked connection region according to the length value of the first distance H1, the first length L1 can be within a reasonable ratio range relative to the first distance H1. That is, the reasonable space between the outer ring electrode 104 in the coil electrode 102 and the side end surface of the non-magnetic layer 20 is fully utilized, and deformation and cracking of the stacked connection region are avoided, thereby improving the reliability of the stacked common mode filter using the electrode structure 10.

[0059] In some other embodiments, the first ratio of the first length to the first distance is greater than or equal to 0.2 and less than or equal to 0.77; and / or the first distance is greater than or equal to 60 μm and less than or equal to 120 μm.

[0060] Specifically, the first ratio of the first length L1 to the first distance H1 may be between 0.2 and 0.77. Optionally, the first ratio may be 0.2, 0.27, 0.34, 0.41, 0.48, 0.55, 0.62, 0.69 or 0.77.

[0061] Optionally, the first length L1 of the stacked connection region on the Y axis can be further optimized by controlling the first distance H1 from the outer ring electrode 104 in the coil electrode 102 to the side end surface of the non-magnetic layer 20 to be between 60 μm and 120 μm.

[0062] N stacked common mode filters using an electrode structure 10 with a first ratio of the first length L1 to the first distance H1 being less than 0.2 are used as a comparative reference, and N stacked common mode filters using an electrode structure 10 with a ratio of the first length L1 to the first distance H1 being greater than 0.2 are used as an embodiment of the present application. An electron microscope is used to observe in SE mode (Scanning Electron) under a preset magnification. The statistical results of the two can be found in Table 1.

[0063] Table 1

[0064]

[0065] Referring to Table 1, it can be seen that the laminated common mode filter made of the electrode structure 10 provided in the embodiment of the present application can significantly reduce the open circuit ratio of the laminated common mode filter in the lead-out part. In the package test of the laminated common mode filter, after the laminated common mode filter has been in the load state for 200 hours, the insulation short circuit failure rate of the laminated common mode filter provided in the embodiment of the present application has also been significantly reduced.

[0066] Please refer to Figure 6 and Figure 7 , Figure 6 (a) is other electrode structures for comparison and reference. Figure 6 (b) is the electrode structure 10 provided in the embodiment of the present application. It can be clearly seen that the printing and forming of the electrode lead-out portion of the electrode structure 10 of the present application is clearer and the cracks are significantly reduced. Figure 7 (a) is other electrode structures for comparison and reference. Figure 7 (b) is the electrode structure provided in the embodiment of the present application. After the electrode structure is sintered, Figure 7 The electrode lead portion of (a) has been completely spread out, while the electrode structure of the present application is stable in shape after sintering.

[0067] To further ensure connection reliability between the first electrode 100 and the second electrode 200 at the connection position, in other embodiments, along the first direction of the non-magnetic layer 20 , the second length L2 of the first connection portion 108 is greater than the third length L3 of the second connection portion 202 .

[0068] See also Figure 3 The first direction of the non-magnetic layer 20 is along the X-axis direction in the figure. Along the first direction, the first connection portion 108 has a second length L2, and the second connection portion 202 has a third length L3.

[0069] The third length L3 of the second connection portion 202 is smaller than the second length L2 of the first connection portion 108 . It can be understood that the shape of the stacked connection region formed by the second connection portion 202 and the first connection portion 108 is defined by the second connection portion 202 .

[0070] During the development or printing process of the second electrode 200, the second electrode 200 may be spread out or deformed and cracked due to the adaptability, thixotropy and screen adhesion of the conductive paste and the non-magnetic layer 20. When the second electrode 200 is subjected to cutting stress, or during the sintering process, the cutting stress and shrinkage stress will aggravate the cracking degree of the thinned second electrode 200. Therefore, it is necessary to control the third length L3 of the second connecting portion 202 within a suitable range to avoid the above situation.

[0071] In this way, the third length L3 of the second connecting portion 202 is controlled to be within a range smaller than the second length L2 of the first connecting portion 108, that is, the spatial range of the first connecting portion 108 is fully utilized, so that the second connecting portion 202 can increase the area covering the first connecting portion 108 as much as possible, while avoiding deformation and cracking caused by the second connecting portion 202 being too wide, thereby improving the reliability of the laminated common mode filter.

[0072] In some other embodiments, the second ratio of the third length L3 to the second length L2 is greater than or equal to 0.47 and less than or equal to 0.84; and / or the second length L2 is greater than or equal to 80 μm and less than or equal to 140 μm.

[0073] Specifically, the second ratio of the third length L3 to the second length L2 may be between 0.47 and 0.84. Optionally, the second ratio may be 0.47, 0.53, 0.59, 0.65, 0.71, 0.77 or 0.84.

[0074] The ratio of the third length L3 to the second length L2 is greater than 0.47, so that the third length L3 of the second connecting portion 202 will not be too small, so as to prevent the printing screen from being blocked or the screen from being difficult to form during the printing of the second electrode. The ratio of the third length L3 to the second length L2 is less than 0.84, so as to prevent the third length L3 of the second connecting portion 202 from being too large and spreading out during the printing process. The spread out second electrode 200 will affect the forming and thickness of the stacked connection area, thereby easily forming microcracks during the sintering process, and also make the second electrode 200 more susceptible to stress during the cutting process to form microcracks.

[0075] N stacked common mode filters using an electrode structure 10 in which the ratio of the third length L3 to the second length L2 is greater than 0.84 are used as a comparative reference, and N stacked common mode filters using an electrode structure 10 in which the ratio of the third length L3 to the second length L2 is less than 0.84 are used as an embodiment of the present application. An electron microscope is used to observe in SE mode (Scanning Electron) under a preset magnification. The statistical results of the two can be found in Table 2.

[0076] Table 2

[0077]

[0078] Referring to Table 2, it can be seen that the laminated common mode filter made of the electrode structure 10 provided in the embodiment of the present application can significantly reduce the open circuit ratio of the laminated common mode filter in the lead-out part. In the package test of the laminated common mode filter, after the laminated common mode filter has been in the load state for 500 hours, the insulation short circuit failure rate of the laminated common mode filter provided in the embodiment of the present application has also been significantly reduced.

[0079] Please refer to Fig. 9 and Fig. 9 , Figure 8 (a) is other electrode structures for comparison and reference. Figure 8 (b) is the electrode structure 10 provided in the embodiment of the present application. It can be clearly seen that the printing and forming of the electrode lead-out portion of the electrode structure 10 of the present application is clearer. Fig. 9 (a) is other electrode structures for comparison and reference. Fig. 9 (b) is the electrode structure provided in the embodiment of the present application. After the electrode structure is sintered, Fig. 9 The electrode lead portion in (a) has a blurred shape and cracks, while the electrode structure of the present application is stable in shape after sintering.

[0080] In other embodiments, a first ratio of the first length L1 to the first distance H1 in the electrode structure 10 and a second ratio of the third length L3 of the second connection portion to the second length L2 of the first connection portion 108 may be comprehensively considered. That is, the first ratio is limited to between 0.47 and 0.84, and the second ratio is limited to between 0.47 and 0.84, so as to further improve the reliability of the laminated common mode filter.

[0081] N stacked common mode filters using the electrode structure 10 that does not comprehensively consider the first ratio and the second ratio, that is, the first ratio and the second ratio are outside the above-mentioned numerical range are used as a comparative reference, and N stacked common mode filters using the electrode structure 10 that comprehensively considers the first ratio and the second ratio are used as an embodiment of the present application. An electron microscope is used in SE mode (Scanning Electron) and observed under preset magnification conditions. The statistical results of the two can be found in Table 3.

[0082] Table 3

[0083]

[0084] Referring to Table 3, it can be seen that the laminated common mode filter made of the electrode structure 10 provided in the embodiment of the present application can significantly reduce the open circuit ratio of the laminated common mode filter in the lead-out part. In the package test of the laminated common mode filter, after the laminated common mode filter has been in the load state for 300 hours, the insulation short circuit failure rate of the laminated common mode filter provided in the embodiment of the present application has also been significantly reduced.

[0085] Please refer to Fig.10 , Fig.10 (a) is other electrode structures for comparison and reference. Fig.10 (b) is the electrode structure 10 provided in the embodiment of the present application. It can be clearly seen that after the finished electrode structure 10 of the present application is ground, it still maintains a clear and stable stacking connection area and has no obvious cracks.

[0086] In order to prevent the second connection portion 202 from spreading out and deforming during printing and short-circuiting with the inner circle electrode 106 of the coil electrode 102, in other embodiments, the second distance H2 between the end of the second connection portion 202 close to the inner circle electrode 106 and the inner circle electrode 106 adjacent to the outer circle electrode 104 of the coil electrode 102 is greater than or equal to 20 μm.

[0087] See also Figure 4 Since the second connecting portion 202 may spread out during the printing process, it is necessary to limit the second distance H2 between the end of the second connecting portion 202 close to the inner circle electrode 106 along the Y-axis direction and the inner circle electrode 106 adjacent to the second connecting portion 202, and H2 is greater than or equal to 20μm to prevent the second connecting portion 202 from spreading out after printing and forming a short circuit with the inner circle electrode 106.

[0088] In other embodiments, the first connection portion 108 is disposed on the non-magnetic layer 20 , and the second connection portion 202 is stacked above the first connection portion 108 ; or the second connection portion 202 is disposed on the non-magnetic layer 20 , and the first connection portion 108 is stacked above the second connection portion 202 .

[0089] The first connection part 108 and the second connection part 202 may be stacked in the Z-axis direction so that the second connection part 202 is stacked above the first connection part 108, that is, the first electrode 100 is first formed on the non-magnetic layer 20, and then the second connection part 202 of the second electrode 200 is formed on the upper surface of the first connection part 108 of the first electrode 100, and then continues to extend toward the side surface of the non-magnetic layer 20 to form the extension part 204 of the second electrode 200. In this way, the positioning of the connection position between the second electrode 200 and the first electrode 100 can be made more accurate.

[0090] Of course, according to the needs of the processing technology, a second electrode (not shown in the figure) can be formed on the non-magnetic layer, and then the first electrode can be formed on the non-magnetic layer formed with the second electrode. In this way, the first connecting portion and the second connecting portion can be stacked in the Z-axis direction in the form that the first connecting portion is stacked above the second connecting portion, so that the first connecting portion of the first electrode covers the second electrode.

[0091] In some other embodiments, along the second direction of the non-magnetic layer 20 , the length of the first connecting portion 108 is greater than the length of the outer ring electrode 104 in the coil electrode 102 .

[0092] In order to further improve the connection strength between the first electrode 100 and the second electrode 200, the area of ​​the stacked connection region where the first electrode 100 and the second electrode 200 are connected can be further expanded. Figure 3 As shown, the length of the first connecting portion 108 for connecting to the second electrode 200 along the Y-axis direction can be lengthened, that is, the length of the first connecting portion 108 along the Y-axis direction is greater than the length of the outer ring electrode 104 of the coil electrode 102, thereby increasing the area of ​​the stacked connection region and improving the connection strength between the first electrode 100 and the second electrode 200.

[0093] In other embodiments, the first electrode 100 includes a first conductive metal powder, the second electrode 200 includes a second conductive metal powder, and the mass ratio of the first conductive metal powder to the first electrode 100 is greater than the mass ratio of the second conductive metal powder to the second electrode 200.

[0094] The first electrode 100 may be formed by preparing a first conductive paste, which may include a first metal powder, an organic solvent and a resin. The organic solvent may be glycol monobutyl ether or butyl carbitol acetate terpineol. The metal of the first conductive metal powder may be at least one of silver, gold, copper, nickel and palladium.

[0095] The second electrode 200 may be formed by preparing a second conductive paste, which may include a first metal powder, an organic solvent, an inorganic powder, and a resin. The organic solvent may be glycol monobutyl ether or butyl carbitol acetate terpineol. The metal of the second conductive metal powder may be at least one of silver, gold, copper, nickel, and palladium.

[0096] It should be noted that in the process of preparing the laminated common mode filter, the second electrode 200 needs to withstand cutting stress, and therefore requires a stronger structural strength than the first electrode 100. Therefore, non-polar powder can be mixed into the slurry for preparing the second electrode to reduce the activity and migration of the second conductive metal powder, thereby further reducing the burning and shrinkage of the second electrode 200 during the sintering process.

[0097] Optionally, the inorganic powder may include at least one of ceramic powder, glass powder, and non-metallic oxide powder.

[0098] In this way, the mass ratio of the first conductive metal powder to the first electrode 100 is greater than the mass ratio of the second conductive metal powder to the second electrode 200. On the one hand, it can ensure that the first electrode 100 has better conductivity, and on the other hand, it can ensure that the second electrode 200 has better durability and stability. In addition, the first electrode 100 and the second electrode 200 are separately manufactured using conductive pastes with different conductive metal contents, which further reduces the overall manufacturing cost of the electrode structure 10.

[0099] In other embodiments, the laminated common mode filter further includes: a first non-magnetic substrate 21, disposed on a side of the first magnetic layer 11 away from the multi-layer stacked non-magnetic layer 20; a second non-magnetic substrate 22, disposed on a side of the second magnetic layer 12 away from the multi-layer stacked non-magnetic layer 20.

[0100] See also Fig.11 The laminated common mode filter is further provided with a first non-magnetic substrate 21 and a second non-magnetic substrate 22 on the first magnetic layer 11 and the second magnetic layer 12 respectively facing away from the non-magnetic layer 20 which is multi-layered.

[0101] Optionally, the first non-magnetic substrate 21 and the second non-magnetic substrate 22 may be made of the same non-magnetic material as the non-magnetic layer 20 , or may be made of different non-magnetic materials.

[0102] It can be understood that due to the different shrinkage rates of magnetic materials and non-magnetic materials during the sintering and curing process, the first magnetic layer 11 and the second magnetic layer 12 are sandwiched between the first non-magnetic substrate 21 and the second non-magnetic substrate 22, and the multi-layer non-magnetic layer 20 is sandwiched between the first magnetic layer 11 and the second magnetic layer 12, so as to match the sintering stress between the layers.

[0103] In this way, by arranging the first non-magnetic substrate 21, the first magnetic layer 11, the multi-layered non-magnetic layer 20, the second magnetic layer 12 and the second non-magnetic substrate 22 in order, the sintering stress between different layers can be matched and adjusted, and the influence of the stress on the electrode structure 10 on the non-magnetic layer 20 can be reduced, so that the laminated common mode filter after sintering and curing has good stability and durability.

[0104] The green body of the laminated common mode filter includes a first non-magnetic substrate 21, a first magnetic layer 11, a plurality of stacked non-magnetic layers 20, a second magnetic layer 12 and a second non-magnetic substrate 22, and the plurality of stacked non-magnetic layers 20 are located between the first magnetic layer 11 and the second magnetic layer 12. External electrodes are arranged on the outside of the green body, and the side surface of the green body along the Z-axis direction can be defined as a side end surface according to the spatial structure. The external electrodes are arranged on the above-mentioned side end surfaces and extend in the upper and lower directions of the green body respectively, and are partially formed on the first non-magnetic substrate 21 and the second non-magnetic substrate 22.

[0105] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A laminated common mode filter, characterized in that: The laminated common mode filter comprises: a first magnetic layer and a second magnetic layer; A multi-layered non-magnetic layer is disposed between the first magnetic layer and the second magnetic layer, and an electrode structure is disposed on at least part of the non-magnetic layer; The electrode structure comprises: a first electrode including a coil electrode disposed on the nonmagnetic layer and a first connecting portion connected to an end of the coil electrode; A second electrode, the second electrode comprising a second connecting portion and an extending portion connected to each other, the second connecting portion being stacked and connected to the first connecting portion to form a stacked connection region, the extending portion being disposed on the non-magnetic layer and extending to a side end surface of the non-magnetic layer; Along the second direction of the non-magnetic layer, a first length of the stacked connection area is positively correlated with a first distance from the outer ring electrode of the coil electrode to the side end surface of the non-magnetic layer, and a first ratio of the first length to the first distance is greater than or equal to 0.2 and less than or equal to 0.77; Along the first direction of the nonmagnetic layer, a second length of the first connection portion is greater than a third length of the second connection portion.

2. The laminated common mode filter according to claim 1, characterized in that The area of ​​the stacked connection region is positively correlated with a first distance from the outer ring electrode of the coil electrode to the side end surface of the non-magnetic layer; or The area of ​​the stacked connection region is positively correlated with the second length of the first connection portion in the first direction of the nonmagnetic layer.

3. The laminated common mode filter according to claim 1, characterized in that: The first distance is greater than or equal to 60 μm and less than or equal to 120 μm.

4. The laminated common mode filter according to claim 1, characterized in that: A second ratio of the third length to the second length is greater than or equal to 0.47 and less than or equal to 0.84; and / or The second length is greater than or equal to 80 μm and less than or equal to 140 μm.

5. The laminated common mode filter according to claim 1, characterized in that: A second distance between the end of the second connecting portion and an inner circle electrode adjacent to the outer circle electrode of the coil electrode is greater than or equal to 20 μm.

6. The laminated common mode filter according to any one of claims 1 to 5, characterized in that: The first connection portion is disposed on the non-magnetic layer, and the second connection portion is stacked on the first connection portion; or The second connection portion is provided on the non-magnetic layer, and the first connection portion is stacked on the second connection portion.

7. The laminated common mode filter according to any one of claims 1 to 5, characterized in that: Along the second direction of the non-magnetic layer, the length of the first connecting portion is greater than the length of the outer ring electrode of the coil electrode.

8. The laminated common mode filter according to any one of claims 1 to 5, characterized in that: The first electrode includes a first conductive metal powder, the second electrode includes a second conductive metal powder, and the mass ratio of the first conductive metal powder to the first electrode is greater than the mass ratio of the second conductive metal powder to the second electrode.

9. The laminated common mode filter according to any one of claims 1 to 5, characterized in that: The laminated common mode filter also includes: A first non-magnetic substrate is disposed on a side of the first magnetic layer away from the multi-layered non-magnetic layer; The second non-magnetic substrate is disposed on a side of the second magnetic layer that is away from the multi-layered non-magnetic layer.

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