Laminated chip inductor and electronic equipment

Abstract

The invention discloses a laminated chip inductor and electronic equipment. The laminated chip inductor comprises an inductor main body and two ends arranged at the inductor main body along a first direction, a first hole and a second hole are respectively formed in a main body part and cover plate parts of the inductor main body, and the cover plate parts are arranged on two surfaces of the main body part along the thickness direction of the inductor main body along the thickness direction of the inductor main body. In the thickness direction of the inductor body, the ratio of the area of the second hole in the cross section of the cover plate part to the area of the cross section of the cover plate part is n1, the ratio of the area of the first hole in the cross section of the body part to the area of the cross section of the body part is n2, and n1 is smaller than n2. According to the laminated chip inductor disclosed by the invention, by controlling the porosity n1 of the cover plate part and enabling the porosity of the cover plate part to be smaller than the porosity n2 of the main body part, the shielding effect of the cover plate part on magnetic leakage radiation of the main body part is improved, so that the situation of magnetic leakage radiation of the inductor main body is improved, and interference of the laminated chip inductor on a circuit in electronic equipment can be avoided.

Description

Technical Field

[0001] This application relates to the field of electronic components technology, and in particular to a multilayer chip inductor and electronic device. Background Technology

[0002] Currently, in multilayer chip inductors, the main material is typically a magnet. When multilayer chip inductors are installed in the circuitry of electronic devices, the magnet may generate leakage magnetic radiation. Furthermore, during operation, as the current increases, the multilayer chip inductor reaches saturation, and the leakage magnetic radiation gradually increases, potentially interfering with the circuitry. For example, when multilayer chip inductors are used in the voice coils of True Wireless Stereo (TWS) earphones or in Buck converters, the increased leakage magnetic radiation may affect the sound quality of the TWS earphones or the stability of the Buck converter. Summary of the Invention

[0003] This application discloses a multilayer chip inductor and an electronic device, which improves the leakage flux of the multilayer chip inductor and enhances the operational stability of the electronic device.

[0004] To achieve the above objectives, in a first aspect, this application discloses a multilayer chip inductor, comprising:

[0005] Inductor body, the inductor body includes:

[0006] The main body has a first hole formed inside it;

[0007] The cover plate portion, the two cover plate portions are respectively disposed on the two surfaces of the main body portion along the thickness direction of the inductor body portion, and a second hole is formed inside the cover plate portion;

[0008] External electrodes, two of which are disposed at both ends of the inductor body along a first direction, the first direction intersecting the thickness direction of the inductor body;

[0009] Wherein, along the thickness direction of the inductor body, the ratio of the area of ​​the second hole on the cross-section of the cover plate to the cross-sectional area of ​​the cover plate is n1, and the ratio of the area of ​​the first hole on the cross-section of the main body to the cross-sectional area of ​​the main body is n2, satisfying: n1 < n2.

[0010] In this application, when the inductor body is provided with a main body and a cover plate, the porosity of the main body and the cover plate is controlled respectively, so that the porosity n1 of the cover plate is less than the porosity n2 of the main body, thereby increasing the density of the cover plate, reducing the magnetic leakage phenomenon of the inductor body, and improving the overall magnetic shielding effect of the multilayer chip inductor 100.

[0011] As some alternative implementations, both the first hole and the second hole are irregular holes;

[0012] The irregular holes include at least one of holes with irregular arrangement and holes with irregular shape.

[0013] In the multilayer chip inductor of this application, when different types or dosages of adhesives are added to the slurry of the main body and the cover plate, the number, shape, and arrangement of the first and second holes in the main body and the cover plate can be different during sintering, thereby controlling the porosity of the main body and the cover plate, so that the porosity of the cover plate is less than that of the main body, and thus the magnetic shielding effect of the cover plate on the main body can be achieved.

[0014] As some alternative implementations, n1 and n2 satisfy: 0.1 < n1 / n2 ≤ 0.8.

[0015] In this application, when controlling the porosity between the main body and the cover plate, the porosity of the main body remains constant, while the porosity ratio between the cover plate and the main body is changed by adjusting the porosity of the cover plate. When the porosity ratio between the cover plate and the main body is less than 0.8, the magnetic shielding effect of the cover plate on the main body is improved, effectively reducing the magnetic leakage of the inductor body. If the porosity ratio between the cover plate and the main body is greater than 0.8, although the leakage magnetic radiation of the inductor body can be reduced to some extent, the magnetic shielding effect of the cover plate on the main body is relatively weak, which is not conducive to meeting the magnetic shielding requirements of some electronic devices, such as headphones.

[0016] As some alternative implementations, the ratio n1 of the area of ​​the second hole on the cross-section of the cover plate to the cross-sectional area of ​​the cover plate satisfies: 1% < n1 ≤ 8%.

[0017] When the porosity of the cover plate portion in this application is controlled at 1%-8%, the density of the cover plate portion is effectively improved, thereby enhancing the magnetic shielding effect on the main body portion. Moreover, when the porosity of the cover plate portion is controlled at 1%-8%, the cover plate portion can maintain a lower porosity relative to the main body portion, and the porosity ratio between the cover plate portion and the main body portion is relatively low, which can reduce the overall leakage magnetic radiation of the inductor body.

[0018] As some alternative implementations, along the thickness direction of the inductor body, the ratio n2 of the area of ​​the first hole on the cross-section of the body to the cross-sectional area of ​​the body satisfies: 10% ≤ n2 ≤ 30%.

[0019] This application considers not only controlling the porosity of the cover portion of the multilayer chip inductor, but also controlling the porosity of the main body portion. Specifically, this application controls the porosity of the main body portion to be between 10% and 30%. On the one hand, if the porosity of the main body portion is greater than 30%, the structure of the main body portion may be too loose, which may lead to more obvious leakage magnetic radiation. On the other hand, if the porosity of the main body portion is less than 10%, the structure of the main body portion may be too dense, which may affect the saturation current of the multilayer chip inductor when it is in operation, and thus affect the electrical performance of the multilayer chip inductor.

[0020] Therefore, this application considers controlling the porosity of the main body to 10%-30%, which can prevent the structure of the main body from being too dense and affecting the electrical performance of the multilayer chip inductor, and also prevent the structure of the main body from being too loose and causing an increase in the magnetic radiation of the multilayer chip inductor, which is beneficial to controlling the magnetic shielding effect of the multilayer chip inductor itself.

[0021] As some alternative implementations, the thickness of the cover portion is d1 along the thickness direction of the inductor body, and d1 is 50μm-600μm.

[0022] In the multilayer chip inductor of this application, the thickness of the cover plate can be controlled to be between 50μm and 600μm. When the cover plate is disposed on the surface of the main body, if the cover plate is too thin (less than 50μm), its relatively thin thickness makes it prone to damage, potentially exposing the electrodes in the main body and affecting the overall electrical performance of the multilayer chip inductor. Furthermore, the exposed main body can lead to magnetic leakage, affecting the use of electronic devices. Conversely, if the cover plate is too thick (greater than 600μm), its relatively excessive thickness may increase the overall thickness of the multilayer chip inductor, which is detrimental to the miniaturization design requirements. Moreover, excessive thickness of the cover plate may increase internal thermomechanical stress during sintering. After sintering and cooling, this internal thermomechanical stress may cause cracking or delamination of the cover plate, increasing its porosity and affecting its magnetic shielding effect.

[0023] Therefore, this application controls the thickness of the cover plate to 50μm-600μm, which not only prevents damage to the cover plate from affecting the electrical performance and magnetic shielding effect of the multilayer chip inductor, but also prevents the cover plate from being too thick. This achieves the design requirement of miniaturization of the multilayer chip inductor while avoiding damage and cracking of the cover plate due to internal stress.

[0024] As some alternative implementations, the thickness of the main body portion along the thickness direction of the inductor body is d2, where d2 is 100μm-2500μm.

[0025] As some alternative embodiments, the cover plate includes at least two thin film layers, which are stacked along the thickness direction of the inductor body; and / or,

[0026] The material of the thin film layer is a nickel-zinc ferrite magnetic and electrical insulating material.

[0027] On the one hand, in the multilayer chip inductor disclosed in this application, when the cover plate is formed by stacking thin film layers, if the thickness of the stacked thin film layers is too small, the cover plate may be relatively thin. Damage to the cover plate can easily expose the electrodes in the main body, affecting the overall electrical performance of the multilayer chip inductor. Furthermore, exposure of the main body can easily lead to magnetic leakage, affecting the use of electronic devices. Therefore, avoiding insufficient stacking of thin film layers in the cover plate is beneficial to improving the protective effect of the cover plate on the main body, preventing the electrodes in the main body from being exposed when the cover plate is damaged, and also preventing magnetic leakage radiation that the cover plate may cause to the main body.

[0028] On the other hand, in the cover plate portion of the multilayer chip inductor disclosed in this application, the material used for each thin film layer can be a nickel-zinc ferrite magnetic electrical insulating material. This material has a high solid content and fine crystals, resulting in a high density and relatively small porosity in the thin film layer. Using this material as a slurry to form the thin film layer is beneficial for controlling the porosity of the cover plate portion.

[0029] As some optional embodiments, the main body includes multiple insulating layers, which are stacked sequentially along the thickness direction of the inductor body. An internal electrode is provided on the insulating layer, and an opening is provided in the insulating layer.

[0030] The main body also includes a connecting electrode, which passes through the opening. When the multiple insulating layers are stacked in sequence, the connecting electrode connects to the inner electrodes on two adjacent insulating layers.

[0031] The insulating layer is made of nickel-zinc ferrite magnetic electrical insulating material.

[0032] On one hand, the slurry of the main body is formed into layers of insulating layers through a casting process. These insulating layers are stacked along the thickness direction of the inductor body to form the main body. Before stacking, internal electrodes can be printed on each insulating layer, and openings can be provided on the insulating layers. When the insulating layers are stacked sequentially, the internal electrodes on adjacent insulating layers are connected by connecting electrodes passing through the openings in the insulating layers. This facilitates the setting and electrical connection of the internal electrodes in the main body.

[0033] On the other hand, in the main body of the multilayer chip inductor disclosed in this application, the material used for each insulating layer can be nickel-zinc ferrite magnetic electrical insulating material. This material has a high solid content and fine crystals, resulting in a high density and relatively small porosity in the insulating layer. Using this material as a paste to form the insulating layer is beneficial for controlling the porosity of the main body.

[0034] Secondly, this application also discloses an electronic device, including a multilayer chip inductor as described in the first aspect.

[0035] The multilayer chip inductor disclosed in this application is placed on the circuit inside the electronic device. Since the multilayer chip inductor itself has a good magnetic shielding effect and low leakage magnetic radiation, the multilayer chip inductor can reduce interference to the circuit and other electronic components inside the electronic device, which is beneficial to improving the stability of the electronic device.

[0036] Compared with the prior art, the beneficial effects of this application are as follows:

[0037] This application discloses a multilayer chip inductor and an electronic device. The multilayer chip inductor includes an inductor body and two ends disposed along a first direction. The inductor body includes a cover plate portion and a main body portion. A first hole and a second hole are respectively formed in the main body portion and the cover plate portion. The cover plate portion is disposed on two surfaces of the main body portion along the thickness direction of the inductor body. Along the thickness direction of the inductor body, the ratio of the area of ​​the second hole in the cross-section of the cover plate portion to the cross-sectional area of ​​the cover plate portion is n1, and the ratio of the area of ​​the first hole in the cross-section of the main body portion to the cross-sectional area of ​​the main body portion is n2, satisfying: n1 < n2. In the multilayer chip inductor disclosed in this application, by controlling the porosity (i.e., n1) of the cover plate portion to make the porosity of the cover plate portion smaller than that of the main body portion (i.e., n2), the shielding effect of the cover plate portion on the leakage magnetic radiation of the main body portion can be improved, thereby improving the leakage magnetic radiation situation of the inductor body. When the multilayer chip inductor is installed in an electronic device, the interference of the multilayer chip inductor on the circuit of the electronic device can be avoided. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in 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.

[0039] Figure 1 This is a schematic diagram of the structure of the multilayer chip inductor disclosed in the embodiments of this application;

[0040] Figure 2 This is an internal schematic diagram of the multilayer chip inductor disclosed in the embodiments of this application;

[0041] Figure 3 This is an exploded view of the inductor body disclosed in the embodiments of this application;

[0042] Figure 4 This is a cross-sectional image of the multilayer chip inductor disclosed in the embodiments of this application;

[0043] Figure 5 for Figure 4 Image of 10% porosity of the main body at point A in the middle;

[0044] Figure 6 for Figure 4 Image of 3% porosity at point B in the cover plate section;

[0045] Figure 7 This is a schematic diagram of the structure of the electronic device disclosed in the embodiments of this application.

[0046] Explanation of reference numerals in the attached figures:

[0047] 100. Multilayer chip inductor; 1. Inductor body; 11. Body portion; 111. Insulating layer; 111a. Opening; 11a. First hole; 11b. First end face; 11c. Second end face; 11d. First surface; 11e. Second surface; 11f. Third surface; 11g. Fourth surface; 12. Cover plate portion; 121. Thin film layer; 12a. Second hole; 2. Outer electrode; 3. Inner electrode; 4. Connecting electrode;

[0048] 200. Electronic equipment; 201. Equipment body. Detailed Implementation

[0049] 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 some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0050] In this application, the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0051] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0052] Furthermore, the terms "installation," "setup," "equipped with," and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0053] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, elements, or components (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, elements, or components. Unless otherwise stated, "a plurality of" means two or more.

[0054] In related technologies, the main material of multilayer chip inductors is typically a magnet. When multilayer chip inductors are installed in the circuitry of electronic devices, the magnets in the inductors may generate leakage magnetic radiation. Furthermore, during the operation of the electronic device, as the current increases, the multilayer chip inductor reaches saturation, and the leakage magnetic radiation gradually increases, potentially interfering with the circuitry. For example, when multilayer chip inductors are used in headphones, True Wireless Stereo (TWS) headphone voice coils, or Buck converters, the increased leakage magnetic radiation may affect the sound quality of TWS headphones or the stability of the Buck converter. Taking the use of multilayer chip inductors in headphones as an example, the inventors discovered that the signal processing circuitry inside the headphones (such as amplifiers and decoding chips) is sensitive to magnetic fields, and the diaphragm of the headphone's driver unit is driven by a magnet. As a result, when the leakage magnetic radiation of the multilayer chip inductor increases, it can interfere with the sensitive circuitry and magnets of the driver unit in the headphones, leading to signal distortion, current noise, background noise, or high-frequency spikes, thus compromising the purity of the sound quality and affecting the user experience. It is evident that the inventors discovered that headphones require high levels of magnetic shielding for multilayer chip inductors, and that magnetic leakage from these inductors has a significant impact on the headphones. Furthermore, existing multilayer chip inductors in related technologies often fail to meet the magnetic leakage shielding requirements for products like headphones.

[0055] In view of the fact that leakage magnetic radiation from multilayer chip inductors may affect the normal operation of some electronic devices' circuits and functions, this application controls the porosity of the cover plate portion of the multilayer chip inductor to make the porosity of the cover plate portion less than that of the main body portion of the multilayer chip inductor, thereby improving the magnetic shielding effect of the cover plate portion on the main body portion and reducing the leakage magnetic radiation of the multilayer chip inductor.

[0056] The technical solution of this application will be further described below with reference to the embodiments and accompanying drawings.

[0057] Please see Figure 1 as well as Figure 2 In the first aspect, this application discloses a multilayer chip inductor 100, including an inductor body 1 and external electrodes 2. The two external electrodes 2 are disposed at both ends of the inductor body 1 along a first direction. The external electrodes 2 are connected to the circuit board to realize the connection between the multilayer chip inductor 100 and the circuit.

[0058] In some embodiments, the inductor body 1 includes a main body portion 11 and a cover plate portion 12, with the two cover plate portions 12 disposed on two surfaces of the main body portion 11 along the thickness direction of the inductor body 1. A first hole 11a is formed inside the main body portion 11, and a second hole 12a is formed inside the cover plate portion 12. The ratio of the area of ​​the second hole 12a on the cross-section of the cover plate portion 12 to the cross-sectional area of ​​the cover plate portion 12 along the thickness direction of the inductor body 1 is n1, i.e., the porosity of the cover plate portion 12 is n1. The ratio of the area of ​​the first hole 11a on the cross-section of the main body portion 11 to the cross-sectional area of ​​the main body portion 11 is n2, i.e., the porosity of the main body portion 11 is n2, satisfying the following relationship: n1 < n2.

[0059] In this application, when the inductor body 1 is provided with the main body portion 11 and the cover plate portion 12, the porosity of the main body portion 11 and the cover plate portion 12 is controlled respectively, so that the porosity n1 of the cover plate portion 12 is less than the porosity n2 of the main body portion 11, thereby increasing the density of the cover plate portion 12, reducing the magnetic leakage phenomenon of the inductor body 1, and improving the overall magnetic shielding effect of the multilayer chip inductor 100.

[0060] It is understood that the multilayer chip inductor 100 disclosed in this application can be a cuboid, a cube, or a cylinder, etc. When the multilayer chip inductor 100 is a cuboid or a cube, the first direction can be the length direction or the width direction of the inductor body 1. When the multilayer chip inductor 100 is a cylinder, the first direction can be the direction of the diameter extension of the circular cross-section of the cylinder.

[0061] It is understood that when the multilayer chip inductor 100 is in the shape of a cuboid or cube, the edges and corners of the multilayer chip inductor 100 can be rounded or chamfered, and this application does not make specific limitations here.

[0062] It is understandable that, such as Figure 1 As exemplified, when the multilayer chip inductor 100 is square, the inductor body 1 has mutually perpendicular length, width, and thickness directions. Wherein, Figure 1 In the diagram, X indicates the length direction of the inductor body 1, Y indicates the width direction of the inductor body 1, and Z indicates the thickness direction of the inductor body 1.

[0063] like Figure 1 and Figure 2 As exemplified, the main body 11 has a first end face 11b and a second end face 11c facing each other along the length direction of the inductor body 1. In the thickness direction of the inductor body 1, which is orthogonal to the length direction of the inductor body 1, the main body 11 has a first surface 11d and a second surface 11e facing each other. Two external electrodes 2 are respectively connected to the first end face 11b and the second end face 11c of the main body 11 along a first direction. Two cover plates 12 are respectively connected to the first surface 11d and the second surface 11e of the main body 11 along the thickness direction of the inductor body 1. In the width direction of the inductor body 1, which is orthogonal to the length direction of the inductor body, the main body has a third surface 11f and a fourth surface 11g facing each other. The third surface 11f and the fourth surface 11g form part of the external surface of the multilayer chip inductor 100.

[0064] Please see Figure 3 In some embodiments, the cover plate portion 12 includes at least two thin film layers 121, which are stacked along the thickness direction of the inductor body 1.

[0065] For example, the slurry of the cover plate portion 12 is formed into layers of thin film layers 121 by casting. Each thin film layer 121 is stacked along the thickness direction of the inductor body 1, and the cover plate portion 12 can be composed of at least two layers of thin film layers 121 stacked together. After the slurry layers of the cover plate portion 12 are stacked to form the cover plate portion 12, it can be stacked on the body portion 11.

[0066] It is understood that the cover plate portion 12 may also include three-layer film layer 121, four-layer film layer 121 or five-layer film layer 121, etc.

[0067] In the multilayer chip inductor 100 disclosed in this application, when the cover plate portion 12 is formed by stacking thin film layers 121, if the thickness of the stacked thin film layers 121 is too small, the cover plate portion 12 may be relatively thin. Damage to the cover plate portion 12 can easily expose the electrodes in the main body portion 11, affecting the overall electrical performance of the multilayer chip inductor 100. Furthermore, exposure of the main body portion 11 can easily lead to magnetic leakage, affecting the use of electronic devices. Therefore, avoiding an insufficient number of thin film layers 121 stacked on the cover plate portion 12 is beneficial to improving the protective effect of the cover plate portion 12 on the main body portion 11, preventing the electrodes of the main body portion 11 from being exposed when the cover plate portion 12 is damaged, and also preventing the cover plate portion 12 from causing magnetic leakage radiation to the main body portion 11.

[0068] Please see Figure 3 In some embodiments, the main body 11 includes multiple insulating layers 111, which are stacked sequentially along the thickness direction of the inductor body 1. Inner electrodes 3 are provided on the insulating layers 111, and openings 111a are provided on the insulating layers 111. The main body 11 also includes a connecting electrode 4, which passes through the openings 111a. When the multiple insulating layers 111 are stacked sequentially, the connecting electrode 4 connects to the inner electrodes 3 on two adjacent insulating layers 111.

[0069] For example, the slurry of the main body 11 is formed into layers of insulating layers 111 by casting. Each insulating layer 111 is stacked along the thickness direction of the inductor body 1 to form the main body 11. Before stacking, internal electrodes 3 can be printed on each insulating layer 111, and openings 111a are provided on the insulating layer 111. When the insulating layers 111 are stacked sequentially, the internal electrodes 3 on adjacent insulating layers 111 are connected by connecting electrodes 4 passing through the openings 111a of the insulating layers 111. This facilitates the setting and electrical connection of the internal electrodes 3 in the main body 11.

[0070] It is understood that after each insulating layer 111 is stacked in sequence, each inner electrode 3 is connected in sequence to form a coil-shaped inner electrode. The coil-shaped inner electrode can be wound counterclockwise or clockwise, and this application does not make specific limitations here.

[0071] For example, please see also Figures 4 to 6 The inductor body 1 is cut along its thickness direction, and the cross-section of the inductor body 1 lies in the plane formed by X and Z. Cross-sectional areas of equal size are taken on the main body 11 and the cover plate 12, respectively. The area occupied by the first hole 11a in the cross-sectional area of ​​the main body 11 and the area occupied by the second hole 12a in the cross-sectional area of ​​the cover plate 12 are calculated to obtain the porosity corresponding to the main body 11 and the cover plate 12.

[0072] In related technologies, multilayer chip inductors 100 generally exhibit magnetic leakage under typical usage scenarios. However, due to their relatively small size, the magnetic leakage of multilayer chip inductors 100 has a relatively small impact on some large electronic devices (such as washing machines and air conditioners) or electronic devices with low magnetic shielding requirements (such as microwave ovens and induction cookers). However, the inventors have found that when multilayer chip inductors 100 are installed in electronic products such as headphones or microphones, taking headphones as an example, the magnetic leakage of multilayer chip inductors 100 has a more significant impact on headphones, mainly because:

[0073] 1. The headphones contain circuits responsible for signal processing (such as amplifiers and decoding chips), which are sensitive to magnetic fields. When the multilayer chip inductor 100 leaks magnetic field, it releases stray magnetic fields that interfere with surrounding circuits or components (such as the magnetic circuit system of the dynamic driver unit and signal transmission lines in the headphones), causing headphone signal distortion and producing noise such as current noise, background noise, or high-frequency spikes, thus compromising the purity of the sound quality.

[0074] 2. Magnetic leakage may interfere with the normal vibration of headphones. For example, the diaphragm in the dynamic driver of headphones relies on a stable magnetic field for driving. The additional magnetic field generated by magnetic leakage will disrupt the original magnetic balance, causing the diaphragm to vibrate irregularly. This will affect the imaging (clarity of sound localization) and dynamic range (ability to express strong and weak sounds), making the sound sound blurry or weak.

[0075] 3. For wireless headphones, which have built-in Bluetooth modules and radio frequency circuits, magnetic leakage may interfere with the reception and transmission of these wireless signals, resulting in unstable signals, disconnections, or increased latency, thus affecting the user experience.

[0076] Therefore, the leakage magnetic field generated by the multilayer chip inductor 100 in headphones is usually mitigated by placing a shielding cover on the multilayer chip inductor 100. However, the inventors found that in small electronic devices like headphones, the shielding cover occupies a large amount of space, which is not conducive to the placement of other electronic components in the headphones.

[0077] The inventors discovered through research that the inductor body 1 of the multilayer chip inductor 100 is made of a high-permeability material, such as manganese-zinc ferrite or amorphous / nanocrystalline soft magnetic alloys. High-permeability materials have high porosity and low density. Magnetic radiation from the main body portion 11 of the inductor body 1 of the multilayer chip inductor 100 may leak through the cover plate portion 12, which has a relatively high porosity. Therefore, magnetic leakage can be reduced by controlling the porosity of the multilayer chip inductor 100. However, since the multilayer chip inductor 100 typically uses uniform material preparation when forming the cover plate portion 12 and the main body portion 11 of the inductor body 1, and then the slurry is cast sequentially to form the main body portion 11 and the cover plate portion 12, the porosity of the cover plate portion 12 formed by uniform slurry is consistent with that of the main body portion 11. Therefore, the cover plate portion 12 is difficult to form an effective magnetic shielding effect on the main body portion 11.

[0078] In this regard, this application adjusts the porosity of the cover plate portion 12 and the main body portion 11 by separately preparing the slurry for the cover plate portion 12 and the main body portion 11 during the preparation of the slurry.

[0079] For example, when configuring the slurry for the cover plate portion 12 and the main body portion 11, a certain amount of adhesive, such as PVB adhesive (Polyvinyl Butyral) or PMMA adhesive (Poly(methyl methacrylate), is added to the slurry for the cover plate portion 12. This reduces the amount of adhesive added and decreases the porosity of the slurry for the cover plate portion 12, thereby reducing the porosity of the cover plate portion 12 after sintering. Alternatively, the amount of adhesive added is increased to adjust the density of the slurry for the main body portion 11, thereby increasing the porosity of the main body portion 11 after sintering.

[0080] For example, the slurry for the main body 11 and the cover plate 12 is prepared by mixing magnetic powder, binder, solvent, etc. The solvent typically evaporates gradually as the main body 11 and cover plate 12 initially form a blank, leaving only the binder to adhere the magnetic powder. Since the binder is a polymer, it occupies space within the blanks of the main body 11 and cover plate 12. During sintering, the binder oxidizes, leaving pores in the sintered main body 11 and cover plate 12, forming the first pore 11a and the second pore 12a in the main body 11 and cover plate 12. Therefore, a higher binder content in the slurry may result in more pores in the main body 11 or cover plate 12. By controlling the amount of binder added, the porosity of the main body 11 and cover plate 12 can be controlled respectively.

[0081] In this way, by controlling the porosity of the cover plate portion 12 and the porosity of the main body portion 11 during the slurry preparation process, the porosity of the cover plate portion 12 is less than that of the main body portion 11. Thus, without the need to add an additional shielding cover, the cover plate portion 12 itself can achieve a magnetic shielding effect on the main body portion 11, thereby reducing the occurrence of magnetic leakage phenomenon of the multilayer chip inductor 100.

[0082] Optionally, the insulating layer 111 may be made of nickel-zinc ferrite magnetic electrical insulating material.

[0083] In the main body 11 of the multilayer chip inductor 100 disclosed in this application, the material used for each insulating layer 111 can be a nickel-zinc ferrite magnetic electrical insulating material. This material has a high solid content and fine crystals, resulting in a high density and relatively small porosity in the insulating layer 111. Using this material as a paste to form the insulating layer 111 is beneficial for controlling the porosity of the main body 11.

[0084] Optionally, the material of the thin film layer 121 may be a nickel-zinc ferrite magnetic and electrical insulating material.

[0085] In the cover plate portion 12 of the multilayer chip inductor 100 disclosed in this application, the material used for each thin film layer 121 can be a nickel-zinc ferrite magnetic electrical insulating material. This material has a high solids content and fine crystals, resulting in high density and relatively low porosity of the thin film layer 121. Using this material as a slurry to form the thin film layer 121 is beneficial for controlling the porosity of the cover plate portion 12. Furthermore, when this material is used as the slurry for the cover plate portion 12, the dosage of the binder added to the slurry can be adjusted, for example, as... Figure 5 as well as Figure 6 For example, when the binder content in the slurry is 9.6%, the porosity of the main body portion formed by the slurry is 10%, and when the binder content is 5.68%, the porosity of the cover portion formed by the slurry is 3%. Therefore, when the slurry used as the cover portion 12 is formed, the porosity of the cover portion 12 can be relatively smaller than that of the main body portion 11, which improves the magnetic shielding effect of the cover portion 12 on the main body portion 11 and reduces magnetic leakage of the multilayer chip inductor 100.

[0086] In some embodiments, both the first hole 11a and the second hole 12a are irregular holes, and the irregular holes are at least one of irregular arrangement holes and irregular shape holes.

[0087] In one example, the first hole 11a and the second hole 12a may be irregularly arranged. For example, different first holes 11a and different second holes 12a may be arranged in any direction within the main body 11 along the first direction or thickness direction of the inductor body 1, rather than being arranged sequentially and at equal intervals in a certain direction. In other words, multiple first holes 11a and multiple second holes 12a are randomly distributed on the cross-section of the main body 11 and the cover plate 12.

[0088] In another example, the first hole 11a and the second hole 12a can be irregularly shaped holes. For example, during molding, different shapes of the first hole 11a and the second hole 12a can form different shapes, such as triangles, quadrilaterals, circles, and stripes. Moreover, the edge shapes of the first hole 11a and the second hole 12a may be straight lines, curves, wavy lines, etc.

[0089] In another example, the first hole 11a and the second hole 12a can be holes arranged in an irregular pattern and with irregular shapes.

[0090] In the multilayer chip inductor 100 of this application, when different types or dosages of adhesives are added to the slurry of the main body 11 and the cover plate 12, the number, shape, and arrangement of the first holes 11a and the second holes 12a in the main body 11 and the cover plate 12 can be different during sintering, thereby controlling the porosity of the main body 11 and the cover plate 12, so that the porosity of the cover plate 12 is less than that of the main body 11, and thus the magnetic shielding effect of the cover plate 12 on the main body 11 can be achieved.

[0091] Please see Figure 5 and Figure 6 In some embodiments, the porosity of the cover plate portion 12 is n1, the porosity of the main body portion 11 is n2, and the porosity ratio between the two satisfies: 0.1 < n1 / n2 ≤ 0.8.

[0092] For example, n1 / n2 can be 0.1-0.2, 0.2-0.3, 0.3-0.4, 0.4-0.5, 0.5-0.6, 0.6-0.7, 0.7-0.8, etc. For example, n1 / n2 can be 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, or 0.8, etc.

[0093] In this application, when controlling the porosity between the main body 11 and the cover plate 12, the porosity of the main body 11 remains constant, and the porosity ratio between the cover plate 12 and the main body 11 is changed by adjusting the porosity of the cover plate 12. When the porosity ratio between the cover plate 12 and the main body 11 is less than 0.8, the magnetic shielding effect of the cover plate 12 on the main body 11 is improved, which can effectively reduce the magnetic leakage of the inductor body 1. If the porosity ratio between the cover plate 12 and the main body 11 is greater than 0.8, although the leakage magnetic radiation of the inductor body 1 can be reduced to a certain extent, the magnetic shielding effect of the cover plate 12 on the main body 11 is relatively weak, which is not conducive to meeting the magnetic shielding requirements of some electronic devices, such as headphones.

[0094] In some embodiments, along the thickness direction of the inductor body 1, the area of ​​the second hole 12a on the cross-section of the cover plate portion 12 and the cross-sectional area of ​​the cover plate portion 12 satisfy: 1% < n1 ≤ 8%.

[0095] For example, n1 can be 1%-2%, 2%-3%, 3%-4%, 4%-5%, 5%-6%, 6%-7%, 7%-8%, etc. For instance, n1 can be 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, or 8%, etc.

[0096] When the porosity of the cover plate portion 12 in this application is controlled at 1%-8%, the density of the cover plate portion 12 is effectively improved, thereby enhancing the magnetic shielding effect on the main body portion 11. Moreover, when the porosity of the cover plate portion 12 is controlled at 1%-8%, the cover plate portion 12 can maintain a lower porosity relative to the main body portion 11, and the porosity ratio between the cover plate portion 12 and the main body portion 11 is relatively low, which can reduce the overall leakage magnetic radiation of the inductor body 1.

[0097] Optionally, along the thickness direction of the inductor body 1, the area of ​​the first hole 11a on the cross-section of the body 11 and the cross-sectional area of ​​the body 11 satisfy: 10% ≤ n2 ≤ 30%.

[0098] For example, n2 can be 10%-15%, 15%-20%, 20%-25%, 25%-30%, etc. For instance, n2 can be 10%, 13%, 15%, 17%, 20%, 23%, 25%, 27%, or 30%, etc.

[0099] This application considers not only controlling the porosity of the cover portion 12 of the multilayer chip inductor 100, but also controlling the porosity of the main body portion 11. Specifically, this application controls the porosity of the main body portion 11 to be between 10% and 30%. On the one hand, if the porosity of the main body portion 11 is greater than 30%, the structure of the main body portion 11 may be too loose, which may lead to a more obvious leakage magnetic radiation phenomenon. On the other hand, if the porosity of the main body portion 11 is less than 10%, the structure of the main body portion 11 may be too dense, which may affect the saturation current of the multilayer chip inductor 100 when the multilayer chip inductor 100 is in operation, and thus affect the electrical performance of the multilayer chip inductor 100.

[0100] Therefore, this application considers controlling the porosity of the main body 11 to 10%-30%, which can prevent the structure of the main body 11 from being too dense and affecting the electrical performance of the multilayer chip inductor 100, and can also prevent the structure of the main body 11 from being too loose and causing an increase in the magnetic radiation of the multilayer chip inductor 100, which is beneficial to controlling the magnetic shielding effect of the multilayer chip inductor 100 itself.

[0101] Please see Figure 2 In some embodiments, the thickness of the cover portion 12 along the thickness direction of the inductor body 1 is d1, which can be 50μm-600μm.

[0102] For example, d1 can be 50μm-100μm, 100μm-150μm, 150μm-200μm, 200μm-250μm, 250μm-300μm, 300μm-350μm, 350μm-400μm, 400μm-450μm, 450μm-500μm, 500μm-550μm, or 550μm-600μm. For example, d1 can be 50μm, 75μm, 100μm, 125μm, 150μm, 175μm, 200μm, 225μm, 250μm, 275μm, 300μm, 325μm, 350μm, 375μm, 400μm, 425μm, 450μm, 475μm, 500μm, 525μm, 550μm, 575μm, or 600μm, etc.

[0103] In the multilayer chip inductor 100 of this application, the thickness of the cover plate portion 12 can be controlled to be 50μm-600μm. When the cover plate portion 12 is disposed on the surface of the main body portion 11, if the cover plate portion 12 is too thin, that is, the thickness of the cover plate portion 12 is less than 50μm, the thickness of the cover plate portion 12 is relatively thin. Damage to the cover plate portion 12 can easily cause the electrodes in the main body portion 11 to be exposed, affecting the overall electrical performance of the multilayer chip inductor 100. Moreover, when the main body portion 11 is exposed, it can easily lead to magnetic leakage, affecting the use of electronic devices. If the cover plate portion 12 is too thick, that is, the thickness of the cover plate portion 12 is greater than 600μm, the relatively excessive thickness of the cover plate portion 12 may cause the overall thickness of the multilayer chip inductor 100 to become thicker, which is not conducive to the miniaturization design requirements of the multilayer chip inductor 100. Furthermore, if the cover plate portion 12 is too thick, the internal thermomechanical stress may increase during the sintering process. After sintering and cooling, the internal thermomechanical stress may cause the cover plate portion 12 to crack or delaminate, resulting in increased porosity and affecting the magnetic shielding effect of the cover plate portion 12.

[0104] Therefore, this application controls the thickness of the cover plate portion 12 to 50μm-600μm, which not only prevents damage to the cover plate portion 12 from affecting the electrical performance and magnetic shielding effect of the multilayer chip inductor 100, but also prevents the cover plate portion 12 from being too thick. This achieves the design requirement of miniaturization of the multilayer chip inductor 100 while avoiding damage and cracking of the cover plate portion 12 due to internal stress.

[0105] Please see Figure 2 In some embodiments, the thickness of the main body 11 along the thickness direction of the inductor body 1 is d2, which can be 100μm-2500μm.

[0106] Exemplarily, d2 can be 100μm-300μm, 300μm-500μm, 500μm-700μm, 700μm-900μm, 900μm-1100μm, 1100μm-1300μm, 1300μm-1500μm, 1500μm-1700μm, 1700μm-1900μm, 1900μm-2100μm, 2100μm-2300μm, 2300μm-2500μm, etc. For example, d2 can be 100μm, 200μm, 300μm, 400μm, 500μm, 600μm, 700μm, 800μm, 900μm, 1000μm, 1100μm, 1200μm, 1300μm m, 1400μm, 1500μm, 1600μm, 1700μm, 1800μm, 1900μm, 2000μm, 2100μm, 2200μm, 2300μm, 2400μm or 2500μm, etc.

[0107] This application controls the thickness of the main body 11 to be between 100μm and 2500μm. Considering that the thickness of the inductor body is mainly controlled by the main body 11, on the one hand, it avoids the thickness of the main body 11 being too small, which is not conducive to the setting of the internal electrodes in the main body 11. On the other hand, it avoids the thickness of the main body 11 being too large, which would cause the overall size of the inductor body 1 to be too large. When the multilayer chip inductor 1 is set in miniaturized products such as wireless headphones, it may occupy a large space, which is not conducive to the miniaturization and lightweight design of wireless headphones.

[0108] To better understand the scheme of the multilayer chip inductor 100 of this application, please refer to the following embodiments.

[0109] Taking the porosity of the main body as an example of controlling it at 10%, please refer to Table 1 below for adjusting the porosity of the cover plate:

[0110] Table 1

[0111]

[0112] It should be noted that the leakage flux change rate in Table 1 is based on Comparative Example 1, thereby obtaining the relative leakage flux change rates of other comparative examples and embodiments.

[0113] Please refer to Table 1 above. When the porosity of the cover plate is controlled below 8% and the porosity of the main body is maintained at 10%, compared with the case where the porosity of the main body and the cover plate are the same, the reduction of the porosity of the cover plate is beneficial to the reduction of leakage flux. When the porosity of the cover plate is greater than that of the main body, the leakage flux of the multilayer chip inductor increases significantly.

[0114] See also Table 2 below:

[0115] Table 2

[0116]

[0117] It should be noted that the leakage flux change rate in Table 2 is based on Comparative Example 6, thereby obtaining the relative leakage flux change rates of other comparative examples and embodiments.

[0118] Please refer to Table 2 above. Compared to the case where the porosity of the main body and the cover plate are the same in Comparative Example 6, when the porosity of the main body is controlled at 16%, although the porosity of the cover plate is less than that of the main body in other comparative examples and embodiments, when the porosity of the cover plate is greater than 8%, the leakage flux change rate of the multilayer chip inductor is small, and the magnetic shielding effect of the cover plate on the main body is weakly improved. When the porosity of the cover plate is less than 8%, the leakage flux of the multilayer chip inductor is significantly reduced, and the magnetic shielding effect is better.

[0119] Please refer to Table 3 below:

[0120] Table 3

[0121]

[0122]

[0123] It should be noted that the leakage flux change rate in Table 3 is based on Comparative Example 10, thereby obtaining the relative leakage flux change rates of other comparative examples and embodiments.

[0124] As shown in Table 3 above, when the porosity of the cover plate portion is maintained at 5%, adjusting the porosity of the main body portion can also affect the leakage flux of the multilayer chip inductor. Compared to Comparative Example 10, where the porosity of both the main body portion and the cover plate portion is controlled at 10%, the reduction in leakage flux of the multilayer chip inductor is more significant when the porosity of the main body portion is between 10% and 30% compared to Comparative Example 10. When the porosity of the main body portion is less than 10%, although the rate of change of leakage flux of the multilayer chip inductor is significantly reduced compared to the case where the porosity is consistent in Comparative Example 10, it is still smaller than the rate of change of leakage flux in Examples 7 and 8. In this regard, if the porosity of the main body is controlled below 10%, on the one hand, when the porosity of the cover plate is controlled at 5%, even if the porosity of the main body is reduced, the benefit of the leakage flux change rate is small. On the other hand, if the porosity of the main body is controlled too small, the structure of the multilayer chip inductor may be too dense. When the multilayer chip inductor is in operation, it will affect the saturation current of the multilayer chip inductor, and thus affect the electrical performance of the multilayer chip inductor.

[0125] Therefore, in summary, the porosity of the cover plate is less than that of the main body, and the porosity of the cover plate is controlled below 8%, while the porosity of the main body is controlled between 10% and 30%. This is beneficial to improving the magnetic shielding effect of the cover plate on the main body and can significantly reduce the leakage flux of the multilayer chip inductor.

[0126] Secondly, please see Figure 7 This application also discloses an electronic device 200, including a multilayer chip inductor 100 as described in the first aspect.

[0127] It is understood that the electronic device 200 also includes a device body 201, and the multilayer chip inductor 100 is disposed on the circuit within the device body 201.

[0128] The multilayer chip inductor 100 disclosed in this application is disposed on the circuit inside the device body 201. Since the multilayer chip inductor 100 has a good magnetic shielding effect and low leakage magnetic radiation, the multilayer chip inductor 100 can reduce interference to the circuit and other electronic components inside the device body 201, which is beneficial to improving the stability of the electronic device 200.

[0129] For example, electronic device 200 may be a wireless headset, Bluetooth headset, or other type of headset.

[0130] The multilayer chip inductor and electronic device disclosed in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the multilayer chip inductor and electronic device and its core ideas. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A multilayer chip inductor, characterized in that, include: Inductor body, the inductor body includes: The main body has a first hole formed inside it; The cover plate portion, the two cover plate portions are respectively disposed on the two surfaces of the main body portion along the thickness direction of the inductor body portion, and a second hole is formed inside the cover plate portion; External electrodes, two of which are disposed at both ends of the inductor body along a first direction, the first direction intersecting the thickness direction of the inductor body; Wherein, along the thickness direction of the inductor body, the ratio of the area of ​​the second hole on the cross-section of the cover plate to the cross-sectional area of ​​the cover plate is n1, and the ratio of the area of ​​the first hole on the cross-section of the main body to the cross-sectional area of ​​the main body is n2, satisfying: n1 < n2.

2. The multilayer chip inductor according to claim 1, characterized in that, Both the first hole and the second hole are irregular holes; The irregular holes include at least one of holes with irregular arrangement and holes with irregular shape.

3. The multilayer chip inductor according to claim 1, characterized in that, The n1 and n2 satisfy the condition: 0.1 < n1 / n2 ≤ 0.

8.

4. The multilayer chip inductor according to claim 1, characterized in that, Along the thickness direction of the inductor body, the ratio n1 of the area of ​​the second hole on the cross-section of the cover plate to the cross-sectional area of ​​the cover plate satisfies: 1% < n1 ≤ 8%.

5. The multilayer chip inductor according to claim 1, characterized in that, Along the thickness direction of the inductor body, the ratio n2 of the area of ​​the first hole on the cross-section of the body to the cross-sectional area of ​​the body satisfies: 10% ≤ n2 ≤ 30%.

6. The multilayer chip inductor according to any one of claims 1-5, characterized in that, Along the thickness direction of the inductor body, the thickness of the cover plate portion is d1, and d1 is 50μm-600μm.

7. The multilayer chip inductor according to any one of claims 1-5, characterized in that, Along the thickness direction of the inductor body, the thickness of the body portion is d2, and d2 is 100μm-2500μm.

8. The multilayer chip inductor according to any one of claims 1-5, characterized in that, The cover plate portion includes at least two thin film layers, which are stacked along the thickness direction of the inductor body; and / or, The material of the thin film layer is a nickel-zinc ferrite magnetic and electrical insulating material.

9. The multilayer chip inductor according to any one of claims 1-5, characterized in that, The main body includes multiple insulating layers, which are stacked sequentially along the thickness direction of the inductor body. An internal electrode is provided on the insulating layer, and an opening is provided in the insulating layer. The main body also includes a connecting electrode, which passes through the opening. When the multiple insulating layers are stacked in sequence, the connecting electrode connects to the inner electrodes on two adjacent insulating layers. The insulating layer is made of nickel-zinc ferrite magnetic electrical insulating material.

10. An electronic device, characterized in that, include: The multilayer chip inductor as described in any one of claims 1-9.

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