Coil assembly

Abstract

The present disclosure provides a coil assembly, the coil assembly comprising: a main body including a support member and a coil portion provided on at least one surface of the support member; and an external electrode connected to the coil portion, wherein the main body includes a plurality of magnetic metal particles, at least some of the plurality of magnetic metal particles include first particles that are plastically deformable, and at least some of the first particles have a deformed surface, the deformed surface having a shape corresponding to the surface of an adjacent magnetic metal particle.

Description

[0001] This application claims the benefit of priority to Korean Patent Application No. 10-2019-0163946, filed with the Korean Intellectual Property Office on Dec. 10, 2019, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0002] The present disclosure relates to a coil assembly. Background Art

[0003] With the miniaturization and thinning of electronic devices such as digital televisions (TVs), mobile phones, laptop computers, etc., miniaturization and thinning of coil assemblies used in such electronic devices have been required. To meet such a demand, research and development of various wound-type coil assemblies or thin-film-type coil assemblies have been actively conducted.

[0004] The main problems based on the miniaturization and thinning of coil assemblies are that even though miniaturization and thinning are achieved, the same characteristics as those of existing coil assemblies are also achieved. To meet such a demand, the proportion of magnetic material in a core filled with magnetic material should be increased. However, there are limitations in increasing the above proportion due to changes in the strength of the inductor body, frequency characteristics based on the insulation characteristics of the body, etc.

[0005] As an example of a method of manufacturing a coil assembly, a method of forming a body by stacking sheets on a coil and then pressing the sheets has been used, in which magnetic particles, resin, etc. are mixed with each other. Fe-based alloys, etc. have been used as examples of magnetic particles to increase the saturation magnetic flux density. Summary of the Invention

[0006] One aspect of the present disclosure lies in providing enhanced characteristics of a coil assembly including magnetic metal powder. To this end, the magnetic characteristics of the coil assembly are improved by improving the filling rate of the magnetic metal powder in the body.

[0007] According to one aspect of the present disclosure, a coil assembly may include: a body including a support member and a coil part disposed on at least one surface of the support member; and an external electrode connected to the coil part, wherein the body includes a plurality of magnetic metal particles, at least some of the plurality of magnetic metal particles include first particles that are plastically deformable, and at least some of the first particles have a deformed surface having a shape corresponding to the surface of an adjacent magnetic metal particle.

[0008] In an exemplary embodiment, the first particles may include an Fe-based crystalline material.

[0009] In an exemplary embodiment, the first particles may include pure iron.

[0010] In an exemplary embodiment, the deformed surface of the first particle may have a shape corresponding to the surface of an adjacent first particle due to its plastic deformation characteristics.

[0011] In an exemplary embodiment, the deformed surface of the first particle may have a recess, and the surface of the adjacent first particle may have a protrusion in a form inserted into the recess.

[0012] In an exemplary embodiment, the plurality of magnetic metal particles includes second particles having a diameter larger than the diameter of the first particle.

[0013] In an exemplary embodiment, the second particles may be formed of a material that does not plastically deform.

[0014] In an exemplary embodiment, the second particles may include an Fe-based amorphous alloy.

[0015] In an exemplary embodiment, the first particles may include an Fe-based crystalline material.

[0016] In an exemplary embodiment, at least some of the second particles may have a spherical shape, and the first particles adjacent to the spherical second particles may have a shape corresponding to the surface of the spherical second particles.

[0017] In an exemplary embodiment, the particle size of the first particles may be 10 μm or less, and the particle size of the second particles may be 20 μm or more.

[0018] In an exemplary embodiment, the coil assembly may further include an insulating layer covering the surface of the coil portion.

[0019] In an exemplary embodiment, the insulating layer may have an integral structure covering the side surface and the upper surface of the coil portion.

[0020] In an exemplary embodiment, the insulating layer may include parylene F.

[0021] In an exemplary embodiment, the insulating layer may include: a first layer covering the side surface and the upper surface of the coil portion; and a second layer covering the first layer.

[0022] In an exemplary embodiment, the first layer may include parylene, and the second layer may include epoxy resin.

[0023] In an exemplary embodiment, the insulating layer may include: a first layer formed along the surface of the coil portion and covering the side surface and the upper surface of the coil portion; and a second layer covering the first layer.

[0024] In an exemplary embodiment, the first layer is an atomic layer deposition (ALD) layer, and the second layer includes parylene. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and other aspects, features, and advantages of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0026] Figure 1 is a schematic perspective view showing a coil assembly according to an exemplary embodiment of the present disclosure;

[0027] Figure 2 and Figure 3 is Figure 1 a cross-sectional view of the coil assembly taken along lines I-I' and II-II', respectively;

[0028] Figure 4 and Figure 5 is a magnified view showing Figure 2 the main body region (region A) in the coil assembly of; and

[0029] Figures 6 to 8 is a view schematically showing a coil portion and an insulating layer covering the coil portion that can be used in a variant coil assembly. DETAILED DESCRIPTION

[0030] Hereinafter, exemplary embodiments of the present disclosure will be described in detail. However, the present disclosure can be implemented in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Therefore, for clarity, the shapes and dimensions of the elements in the drawings may be enlarged, and the same reference numerals will always be used to denote the same or similar elements.

[0031] Figure 1 is a schematic perspective view showing a coil assembly according to an exemplary embodiment of the present disclosure, Figure 2 and Figure 3 is Figure 1 a cross-sectional view of the coil assembly taken along lines I-I' and II-II', respectively. Figure 4 and Figure 5 is a magnified view showing Figure 2 the main body region (region A) in the coil assembly of.

[0032] Referring to Figure 1 , the coil assembly 100 according to an exemplary embodiment has a structure mainly including a main body 101 embedded with a support member 102 and a coil portion 103, and outer electrodes 105 and 106. As Figure 4 and Figure 5As shown, the main body 101 includes a plurality of magnetic metal particles, and at least some of the plurality of magnetic metal particles include plastically deformable first particles 111. At least some of the first particles 111 have a deformed surface and thus have a shape corresponding to the surface of adjacent magnetic metal particles.

[0033] The main body 101 seals and supports the support member 102, the coil part 103, etc. to protect the support member 102, the coil part 103, etc., or may form the exterior of the coil assembly 100. As Figure 4 As shown, the main body 101 includes a plurality of magnetic metal particles. In this case, the main body 101 may be in a form in which magnetic metal particles are dispersed in an insulating main body 110 formed of a resin or the like. The insulating main body 110 may be formed of a thermosetting resin, a thermoplastic resin, a wax-based material, an inorganic material, or the like. The magnetic metal particles 111 and 112 may include an Fe-based alloy or pure Fe having excellent magnetic properties. As described above, the plurality of magnetic metal particles include plastically deformable first particles 111. In addition, as Figure 4 As shown, the plurality of magnetic metal particles include second particles 112 having a diameter larger than the diameter of the first particles 111. In the case of the present exemplary embodiment, by forming the first particles 111 of a plastically deformable material, the main body 101 can be molded under high pressure. Therefore, the filling rate of the first particles 111 and the second particles 112 in the main body 101 can be improved. This will be described in more detail below.

[0034] Due to the characteristics exhibited by the coils of the coil part 103, the coil part 103 plays various roles in an electronic device. For example, the coil assembly 100 may be a power inductor, and in this case, the coil part 103 stores electric power in a magnetic field to maintain the output voltage, thereby stabilizing the electric power. To this end, the coil part 103 may have a spiral shape forming at least one turn and may be formed on at least one surface of the support member 102. In the exemplary embodiment, the coil part 103 is shown to include a first coil pattern 103a and a second coil pattern 103b, and the first coil pattern 103a and the second coil pattern 103b are provided on two opposite surfaces of the support member 102. In this case, the first coil pattern 103a and the second coil pattern 103b may include pad regions P and may be connected to each other via vias V passing through the support member 102. Such coil patterns 103a and 103b may be formed by methods used in the art such as plating methods (e.g., pattern plating, anisotropic plating, isotropic plating, etc.), and may be formed into a multilayer structure using a variety of the above methods. As shown in the figure, the coil patterns 103a and 103b may have a core region C in the central region. The material forming the main body 101 may be filled in the core region C of the coil part 103.

[0035] The lead-out pattern L is provided in the outermost region of the coil part 103 to provide a connection path to the outer electrodes 105 and 106 and may be formed integrally with the coil part 103. In this case, as shown in the figure, the lead-out pattern L may have a width larger than the width of the coil pattern of the coil part 103 to be connected to the outer electrodes 105 and 106. As used herein, the term "width" refers to the width in the X direction based on Figure 1 of.

[0036] The support member 102 for supporting the coil part 103 may be formed of a polypropylene glycol (PPG) substrate, a ferrite substrate, a metal-based soft magnetic substrate, or the like. In this case, a through hole may be formed in the central region of the support member 102, and a magnetic material may be filled in the through hole to form a core region C. The core region C constitutes a part of the main body 101. As described above, the core region C filled with the magnetic material may be formed to improve the performance of the coil assembly 100.

[0037] The outer electrodes 105 and 106 may be formed outside the main body 101 to be connected to the lead-out pattern L. The outer electrodes 105 and 106 may be formed of a paste containing a metal having excellent conductivity (for example, a conductive paste containing nickel (Ni), copper (Cu), tin (Sn), silver (Ag), or an alloy thereof). In addition, a plating layer may be further formed on the outer electrodes 105 and 106. In this case, the plating layer may include at least one selected from the group consisting of nickel (Ni), copper (Cu), and tin (Sn); for example, a nickel (Ni) layer and a tin (Sn) layer may be sequentially formed.

[0038] As previously described, the magnetic metal particles 111 and 112 include the first particles 111 and the second particles 112, and the particle size of the first particles 111 is smaller than the particle size of the second particles 112. By employing the first particles 111 that are plastically deformable and have a relatively small particle size, the filling rate of the magnetic metal particles 111 and 112 in the main body 101 can be improved. The first particles may have a particle size of 10 μm or less, and the second particles may have a particle size of 20 μm or more.

[0039] The first particles 111 are plastically deformable metal particles and contain, for example, an Fe-based crystalline material. Specifically, the first particles 111 may contain pure iron, for example, carbonyl iron powder (CIP). When the body 101 is formed by high-pressure molding, at least a part of the first particles 111 is plastically deformed, and thus, their surfaces may have a shape corresponding to the surfaces of adjacent first particles 111. As used herein, the expression "a shape corresponding to the surface of an adjacent particle" means that at least a part of the surface of the first particle 111 is deformed to be complementary to the surface of an adjacent first particle 111. As an example of such a form, the surface of the first particle 111 includes a recessed portion P2, and the surface of an adjacent first particle has a protruding portion P1, and the protruding portion P1 is in a form inserted into the recessed portion P2 (as shown in Figure 4 ). In this case, the first particle 111 may be in contact with an adjacent first particle 111, or an insulating body 110 or the like may be provided therebetween, and the first particle and the adjacent first particle do not contact each other. Since the first particles 111 are plastically deformed and thus have the previously described surfaces, the filling rates of the magnetic metal particles 111 and 112 can be increased. As used herein, the term "filling rate" may be defined as the volume occupied by the magnetic metal particles 111 and 112 in the body 101.

[0040] Compared with the first particles 111, the second particles 112 have a larger particle size. Using particles with different diameter distributions helps to increase the filling rates of the magnetic metal particles 111 and 112 in the body 101 compared to when using a single type of particle. Contrary to the first particles 111, the second particles 112 may be a material that does not plastically deform. For this purpose, the second particles 112 may contain an Fe-based amorphous alloy. Specifically, the second particles 112 may contain at least one selected from the group consisting of Fe, Si, Cr, B, and Ni; for example, the second particles 112 may be amorphous Fe-Si-B-Cr metal, but are not limited thereto. As a more specific example, the magnetic metal particles 111 and 112 may be formed using an Fe-Si-B-Nb-Cr alloy, an Fe-Ni alloy, etc. As used herein, the expression "the second particles 112 do not plastically deform" means having a lower plastic deformation ability than the first particles, and this expression does not mean that plastic deformation does not occur at all, but is considered to have almost no plastic deformation, and thus substantially no plastic deformation.

[0041] At least some of the second particles 112 having a low plastic deformation ability remain in a spherical shape as shown in the figure. The first particles 111 adjacent to the spherical second particles 112 may have a shape corresponding to their surfaces. That is, the first particles 111 adjacent to the second particles 112 may have a surface that is partially concave. The surface of the recessed area may be a part of a spherical shape.

[0042] AlthoughFigure 4 shows the shapes of the first particles 111 and the second particles 112 having different particle size distributions, but three types of particles having different particle size distributions can be employed. Alternatively, a single type of particle can be used, as Figure 5 shown. In this case, only the first plastically deformable particles 111 are included in the main body 101, and due to the high-pressure molding, the first particles 111 can have a surface shape corresponding to adjacent first particles 111.

[0043] In addition, when the main body 101 is subjected to high-pressure molding, an insulating structure is required to insulate the coil portion 103 from the magnetic metal particles 111 and 112. As Figures 6 to 8 shown, an insulating layer covering the coil portion 103 can be employed. In the present disclosure, the mechanical stability and insulation performance of the coil portion 103 are improved by adopting a material and shape of such an insulating layer suitable for high-pressure molding.

[0044] In Figure 6 the embodiment depicted, the insulating layer 120 covers the surface of the coil portion 103; specifically, the insulating layer 120 can be integrally formed to cover the side surface and the upper surface of the coil portion 103. The insulating layer 120 can include F-type parylene. Compared with N-type parylene, F-type parylene has excellent tensile strength and yield strength, enabling the insulating layer 120 to more effectively protect the coil portion 103. Parylene is a group of polymers having a p-xylene structure. Parylene includes various types such as N-type, C-type, D-type, F-VT4 type, and F-AT4 type.

[0045] In Figure 7 the embodiment depicted, the insulating layer includes a double-layer structure; specifically, the first layer 121 covers the side surface and the upper surface of the coil portion 103, while the second layer 122 covers the first layer 121. In contrast to Figure 6 this, since the insulating layer has an additional insulating structure as the second layer 122, the parylene included in the insulating layer does not need to be limited to a specific type, and thus the first layer 121 can include parylene other than F-type parylene (of course, F-type parylene can also be included). The second layer 122 includes epoxy resin. The epoxy resin included in the second layer 122 is advantageous for various types of precursors and composition designs. In addition, the epoxy resin has excellent adhesiveness, and thus can be used to achieve a more stable insulating structure.

[0046] Figure 8An insulating layer having a double-layer structure is shown; specifically, the first layer 123 covers the side surface and the upper surface of the coil portion 103 and is formed along the surface of the coil portion, and the second layer 124 covers the first layer 123. The first layer 123 may be a layer formed by atomic layer deposition (ALD) (ALD layer), and may include ceramic materials such as, for example, Al2O3, TiO2, ZrO2, etc. The ALD layer may have a small thickness of several hundred nanometers, and thus, the first layer 123 may have a shape corresponding to the surface structure of the coil portion 103. Although this ALD layer has a small thickness, it has excellent insulating properties and strength, and thus may have a stable insulating structure. The second layer 124 may include parylene (e.g., parylene F) or other materials such as epoxy resin.

[0047] As described above, in the coil assembly according to an exemplary embodiment of the present disclosure, the filling rate of the magnetic metal powder in the body is improved, thereby enhancing characteristics such as inductance.

[0048] Although the exemplary embodiments have been shown and described above, it will be apparent to those skilled in the art that modifications and changes can be made without departing from the scope of the invention defined by the appended claims.

Claims

1. A coil assembly, comprising: A main body, comprising a support member and a coil portion provided on at least one surface of the support member; And An external electrode, connected to the coil portion, Wherein, the main body comprises a plurality of magnetic metal particles, At least some of the plurality of magnetic metal particles comprise first particles that are plastically deformable, At least some of the first particles have a deformed surface, and the deformed surface has a shape corresponding to the surface of an adjacent magnetic metal particle, Wherein, the coil assembly further comprises an insulating layer covering the surface of the coil portion, and Wherein, the insulating layer comprises: A first layer, covering the side surface and the upper surface of the coil portion; and A second layer, covering the side surface and the upper surface of the first layer.

2. The coil assembly according to claim 1, wherein, The first particles comprise an Fe-based crystalline material.

3. The coil assembly according to claim 1, wherein, The first particles comprise pure iron.

4. The coil assembly according to claim 1, wherein The main body further comprises an insulating main body, and adjacent first particles are in contact with each other, or the insulating main body is provided between adjacent first particles.

5. The coil assembly according to claim 1, wherein, The deformed surface of the first particle has a recessed portion, and the surface of the adjacent first particle has a protruding portion, and the protruding portion is in a form inserted into the recessed portion.

6. The coil assembly according to claim 1, wherein, The plurality of magnetic metal particles comprise second particles having a diameter larger than that of the first particles.

7. The coil assembly according to claim 6, wherein, The second particles comprise a material that is not plastically deformable.

8. The coil assembly according to claim 6, wherein, The second particles comprise an Fe-based amorphous alloy.

9. The coil assembly according to claim 8, wherein, The first particles comprise an Fe-based crystalline material.

10. The coil assembly according to claim 6, wherein, At least some of the second particles have a spherical shape, and the first particles adjacent to the spherical second particles have a shape corresponding to the surface of the spherical second particles.

11. The coil assembly according to claim 6, wherein, The particle size of the first particles is 10 μm or less, and the particle size of the second particles is 20 μm or more.

12. The coil assembly according to any one of claims 1 to 11, wherein, The deformed surface of the first particle has a shape corresponding to the surface of an adjacent first particle.

13. The coil assembly according to claim 3, wherein, The pure iron comprises carbonyl iron powder.

14. The coil assembly according to claim 1, wherein, The first layer comprises parylene, and the second layer comprises epoxy resin.

15. The coil assembly according to claim 1, wherein, The first layer is formed along the surface of the coil portion.

16. The coil assembly according to claim 15, wherein, The first layer is an atomic layer deposition layer, and The second layer comprises parylene.

17. The coil assembly according to claim 14 or 16, wherein, The parylene comprises parylene F.

18. A coil assembly, comprising: A main body, comprising a support member and a coil portion provided on at least one surface of the support member; And An external electrode, connected to the coil portion, Wherein, the main body comprises a plurality of magnetic metal particles, At least some of the plurality of magnetic metal particles comprise first particles that are plastically deformable, At least some of the first particles have a deformed surface, and the deformed surface has a shape corresponding to the surface of an adjacent magnetic metal particle, Wherein, the coil assembly further comprises an insulating layer covering the surface of the coil portion, and Wherein, the insulating layer has an integral structure covering the side surface and the upper surface of the coil portion, and the insulating layer comprises parylene F.

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