inductor

Abstract

Provided is an inductor that can achieve high bias characteristics while maintaining a high inductance value even at high currents. [Solution] The present invention provides an inductor that includes a main body including first magnetic material portions above and below a coil, and second magnetic material portions above and below the first magnetic material portions, and that can achieve high bias characteristics while maintaining a high inductance value at high currents because the magnetic flux density of the first magnetic material included in the first magnetic material portion is higher than the magnetic flux density of the second magnetic material included in the second magnetic material portion.

Description

[Technical Field]

[0001] The present invention relates to an inductor. [Background technology]

[0002] 2. Description of the Related Art Inductors are one of the important passive elements that constitute electronic circuits along with resistors and capacitors, and can be used to remove noise or as a component that constitutes an LC resonant circuit.

[0003] Such an inductor can be mounted in an AP, CP, charger, or PMIC of a display of a smartphone or wearable device to serve as a power supply.

[0004] Conventional inductors have a body made of a single-composition magnetic material, with magnetic flux flowing around the coil.

[0005] Smartphones and multi-input multi-output (MIMO) communications, which have recently become a hot topic, require inductors to have a DC bias of at least 2A or more, and to achieve high inductance even at high currents. However, conventional inductors generally do not have a high DC bias, making it difficult to meet these conditions.

[0006] As a result, with the trend toward higher current products, there is an increasing demand for inductors that have excellent bias characteristics while maintaining a constant inductance value. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-201374 Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to provide an inductor that can achieve high bias characteristics while maintaining a high inductance value even at high currents. [Means for solving the problem]

[0009] One aspect of the present invention provides an inductor including a main body including first magnetic material portions above and below a coil, and second magnetic material portions above and below the first magnetic material portion, wherein the magnetic flux density of the first magnetic material included in the first magnetic material portion is higher than the magnetic flux density of the second magnetic material included in the second magnetic material portion. [Effects of the Invention]

[0010] According to one embodiment of the present invention, it is possible to improve the bias characteristics of an inductor while maintaining a high inductance value at a high current. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a transparent perspective view schematically illustrating an inductor according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view taken along line II' in FIG. [Figure 3] 1 is an SEM photograph showing the internal structure of an inductor according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. Furthermore, the embodiments of the present invention are provided to more completely explain the present invention to those having average knowledge in the art. Therefore, the shapes and sizes of elements in the drawings may be enlarged or reduced (or highlighted or simplified) for clearer explanation.

[0013] Furthermore, throughout the specification, unless specifically stated to the contrary, "comprising" an element means that it can further include other elements, rather than excluding other elements.

[0014] FIG. 1 is a transparent perspective view schematically showing an inductor according to one embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line II' in FIG. 1, and FIG. 3 is an SEM photograph showing the internal structure of an inductor according to one embodiment of the present invention.

[0015] In the following description, in the drawings, the L direction is the length direction of the main body 50, the W direction is the width direction, and the T direction is the thickness direction.

[0016] In addition, the opposing surfaces of the main body 50 in the T direction are defined as the first and second surfaces S1 and S2, the opposing surfaces in the L direction are defined as the third and fourth surfaces S3 and S4, and the opposing surfaces in the W direction are defined as the fifth and sixth surfaces S5 and S6.

[0017] 1 to 3, an inductor 100 according to this embodiment includes a support 20 on which a coil is arranged, and a body 50. As shown in FIG.

[0018] The main body 50 forms the external appearance of the inductor 100 and may have a generally rectangular parallelepiped shape.

[0019] The main body 50 includes a first magnetic part 52 and a second magnetic part 51 .

[0020] The first magnetic material part 52 is located at the center in the T direction, and includes a core 52c, and first and second inner layers 52a, 52b disposed on the upper and lower surfaces of the support 20, respectively.

[0021] Here, the core 52c refers to a core hole formed in the center of the main body 50 so as to penetrate the support 20 and is filled with the first magnetic material.

[0022] In this way, by forming core 52c filled with the first magnetic material inside main body 50, the inductance of inductor 100 can be further improved compared to when no core is present.

[0023] The second magnetic material part 51 also includes first and second outer layers 51a and 51b that are disposed on the upper and lower surfaces of the first magnetic material part 52, respectively.

[0024] In this case, the main body 50 is configured such that the magnetic flux density of the first magnetic material included in the first magnetic material part 52 is higher than the magnetic flux density of the second magnetic material included in the second magnetic material part 51.

[0025] The support 20 is disposed within the first magnetic part 52 .

[0026] Such a support 20 can be made of a substrate of an insulating or magnetic material, for example, the insulating material can be a photosensitive polymer and the magnetic material can be ferrite, but the present invention is not limited thereto.

[0027] The coils may also include first and second coils 42, 44 disposed on either side of the support 20 in the T direction.

[0028] The first and second coils 42, 44 may each be formed to have a helical structure, but may be modified to other configurations as desired.

[0029] For example, the first and second coils 42, 44 may be formed into polygonal shapes such as squares, pentagons, and hexagons, circles, ellipses, etc., and may also be formed into irregular shapes as needed.

[0030] Such first and second coils 42, 44 may include one or more metals selected from the group consisting of gold, silver, platinum, copper, nickel, palladium, and alloys thereof.

[0031] However, the present invention is not necessarily limited to this, and it is sufficient that the first and second coils 42, 44 are made of a material that can provide electrical conductivity.

[0032] The first coil 42 has a first lead portion 42a at one end thereof, which is exposed on the third surface S3 of the main body 50.

[0033] The second coil 44 has a second lead portion 44a at one end thereof that is exposed to the fourth surface S4 of the main body 50.

[0034] The other ends of the first and second coils 42 and 44 are arranged to face each other in the T direction and can be electrically connected to each other through vias 46 .

[0035] The vias 46 can be formed by forming via holes in the support 20 and the other ends of the first and second coils 42 and 44 so as to penetrate in the T direction, and then filling the via holes with conductive paste.

[0036] In this case, the conductive paste may contain one or more metals selected from the group consisting of gold, silver, platinum, copper, nickel, palladium, and alloys thereof, but the present invention is not necessarily limited thereto, and it is sufficient if the conductive paste is made of a material that can provide conductivity.

[0037] Meanwhile, in order to insulate the first and second coils 42, 44 from the body 50, an insulating film 60 may be formed around the first and second coils 42, 44 to cover the surfaces of the first and second coils 42, 44.

[0038] Such an insulating film 60 is made of a material having insulating properties, and for example, a polymer or the like can be used, but the present invention is not limited to this.

[0039] The first and second magnetic material parts 52 and 51 of the main body 50 may be formed of first and second magnetic materials, respectively, made of a paste containing a composite of a metal powder such as ferrite and a polymer.

[0040] The first and second magnetic bodies may be contained in a form in which metal powder is dispersed on a polymer, thereby ensuring surface insulation.

[0041] The metal powder may include at least one of iron (Fe), nickel-iron alloy (Ni-Fe), sendust (Fe-Si-Al), and iron-silicon-chromium alloy (Fe-Si-Cr).

[0042] The first magnetic material portion 52 may include a first internal layer 52a covering the upper side of the first coil 42, a second internal layer 52b covering the lower side of the second coil 44, and a core 52c formed in the center of the main body 50.

[0043] The first magnetic material part 52 is made of a first magnetic material having a higher magnetic flux density than the second magnetic material part 51.

[0044] In this case, the magnetic flux density of the first magnetic body may be 1.4 to 1.7 T (Tesla).

[0045] If the magnetic flux density of the first magnetic body is less than 1.4 T, there is a possibility that the bias characteristics may be deteriorated. Also, if the magnetic flux density of the first magnetic body is more than 1.7 T, the magnetic body may crystallize, and the coercive force may become 5.0 Oe (1 Oe = 1 / 4π × 10 3 A / m) or more.

[0046] Furthermore, the Fe content in the first magnetic body is inversely proportional to the amount of resin contained in the first magnetic body, and as the resin content increases, the flow of magnetic flux is further obstructed, which may result in a relative decrease in the inductance of inductor 100.

[0047] If the first magnetic body has a high Fe content and therefore an excessively low resin content, there is a possibility that the processability for forming the main body will not be fully realized.

[0048] In this embodiment, the Fe content of the first magnetic body can be 78 to 83 at %.

[0049] If the Fe content of the first magnetic body is less than 78 at%, there is a possibility that a problem of insufficient high current characteristics may occur, and if the Fe content of the first magnetic body is more than 83 at%, there is a possibility that amorphous atomization characteristics may not be fully realized, and there is a possibility that a problem of crystallization may occur in the amorphous state.

[0050] Meanwhile, in the first magnetic part 52, the first inner layer 52a covering the upper side of the first coil 42 and the second inner layer 52b covering the lower side of the second coil 44 may each have a thickness of 70 to 120 μm.

[0051] In this case, if the thicknesses of the first and second internal layers 52a, 52b of the first magnetic material part 52 are each less than 70 μm, the path of the first magnetic material part 52 will become narrower, making the magnetic flux more likely to saturate, which may result in a problem of reduced bias characteristics.

[0052] Furthermore, if the thickness of each of the first and second inner layers 52a, 52b of the first magnetic material part 52 exceeds 120 μm, the magnetic permeability may decrease, which may cause a problem in that the inductance value of the inductor 100 decreases.

[0053] The second magnetic material part 51 may include first and second outer layers 51a and 51b that are respectively arranged outside (above and below) the first and second inner layers 52a and 52b of the first magnetic material part 52 in the T direction.

[0054] The second magnetic material part 51 is made of a second magnetic material having a lower magnetic flux density than the first magnetic material of the first magnetic material part 52.

[0055] In this case, the Fe content of the second magnetic body may be 76 at% or less. If the Fe content of the second magnetic body exceeds 76 at%, the magnetic permeability may decrease, which may cause a problem of a decrease in the inductance value of the inductor 100.

[0056] Furthermore, the second magnetic body has a lower Fe content of 76 at % or less than that of the first magnetic body, resulting in a lower bias characteristic but a higher magnetic permeability. In this case, if the magnetic flux density of the second magnetic body is less than 1.1 T, a problem of a lower bias characteristic may occur, while if the magnetic flux density of the second magnetic body exceeds 1.3 T, a problem of a lower magnetic permeability may occur, resulting in a lower inductance value of the inductor 100. Therefore, the magnetic flux density of the second magnetic body may be 1.1 to 1.3 T.

[0057] Meanwhile, in this embodiment, the total volume of the first magnetic material part 52 can be 33 to 75% of the total volume of the second magnetic material part 51, taking into consideration the balance between the DC resistance (Rdc) and inductance (Ls) due to the thickness of the coil.

[0058] If the total volume of the first magnetic body part 52 is less than 33% of the total volume of the second magnetic body part 51, a problem of reduced bias characteristics may occur, and if the total volume of the first magnetic body part 52 is more than 75% of the total volume of the second magnetic body part 51, a problem of reduced inductance capacity of the inductor 100 may occur.

[0059] The inductor 100 according to this embodiment may further include first and second external electrodes 81 and 82 disposed on the surface of the body 50 .

[0060] The first external electrode 81 is disposed on the third surface S3 of the main body 50.

[0061] The first external electrode 81 may include a first connection portion 81a and a first band portion 81b.

[0062] The first connection portion 81a is a portion formed on the third surface S3 of the main body 50, and is connected to the exposed portion of the first lead portion 42a of the first coil 42.

[0063] The first band portion 81b extends from the first connection portion 81a to the first and second surfaces S1, S2 and parts of the fifth and sixth surfaces S5, S6 of the main body 50, and serves to increase the fixing strength of the first external electrode 81.

[0064] The second external electrode 82 is disposed on the fourth surface S4 of the main body 50.

[0065] The second external electrode 82 may include a second connection portion 82a and a second band portion 82b.

[0066] The second connection portion 82a is a portion formed on the fourth surface S4 of the main body 50, and is connected to the exposed portion of the second lead portion 44a of the second coil 44.

[0067] The second band portion 82b extends from the second connection portion 82a to the first and second surfaces S1, S2 and parts of the fifth and sixth surfaces S5, S6 of the main body 50, and serves to increase the fixing strength of the second external electrode 82.

[0068] The first and second external electrodes 81 and 82 may be made of a metal capable of imparting conductivity, for example, one or more metals selected from the group consisting of gold, silver, platinum, copper, nickel, palladium, and alloys thereof.

[0069] Furthermore, a nickel plating layer (not shown) or a tin plating layer (not shown) may be formed on the surfaces of the first and second external electrodes 81 and 82, if necessary.

[0070] When a current is applied to an inductor, a magnetic flux is generated around the coil. The density of the magnetic flux is strongest around the coil and gradually decreases as you move away from the coil.

[0071] To improve the bias characteristics of such an inductor, it is necessary to increase the magnetic flux density (the capacity that allows magnetic flux to pass per unit volume) of the magnetic material surrounding the coil so that a strong magnetic flux can flow smoothly around the coil, thereby making it easier for the magnetic flux to saturate.

[0072] In the inductor 100 according to this embodiment, the first magnetic part 52 is made of a first magnetic material having an Fe content of 78 at% or more, low magnetic permeability but high magnetic flux density, and the second magnetic material of the second magnetic part 51 has an Fe content of 76 wt% or less, high magnetic permeability but relatively low magnetic flux density and bias characteristics.

[0073] That is, the inductor 100 is made of a first magnetic material having a composition with high magnetic flux density around the coil where the magnetic flux density is concentrated, and the second magnetic material part 51 corresponding to the outer cover area of ​​the main body 50 is made of a second magnetic material having a lower magnetic flux density than the first magnetic material but a relatively high magnetic permeability.

[0074] Therefore, by alleviating the saturation of the magnetic flux concentrating around the coil and increasing the magnetic flux saturation current (bias current), the high current characteristics can be improved, and the bias characteristics can be improved by 15 to 20% compared to conventional inductors made only of magnetic material with low magnetic flux density, without reducing the inductance value.

[0075] Although the embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that the scope of the present invention is not limited thereto, and that various modifications and variations are possible within the scope of the technical idea of ​​the present invention as set forth in the claims. [Explanation of symbols]

[0076] 20 Support 42, 44 First and second coils 42a, 44a First and second lead portions 46 Beer 50 main body 51 Second magnetic body part 51a, 51b First and second outer layers 52 First magnetic body part 51a, 52b First and second inner layers 52c Core 60 insulating film 81, 82 First and second external electrodes 81a, 82a First and second connecting portions 81b, 82b First and second band parts

Claims

1. a main body including first magnetic material portions above and below a coil, and second magnetic material portions above and below the first magnetic material portions; the first magnetic body included in the first magnetic body portion includes a first metal powder containing Fe, and the content of Fe in the first magnetic body is 78 to 83 at %, the second magnetic body included in the second magnetic body portion includes a second metal powder containing Fe, and the content of Fe in the second magnetic body is 76 at % or less, and the first magnetic body has non-crystallization characteristics; The first magnetic material portion includes a first internal layer covering an upper side of the coil and a second internal layer covering a lower side of the coil, and the thickness of the first internal layer and the second internal layer is 70 to 120 μm. Inductor.

2. The inductor according to claim 1 , wherein a core is formed in the center of the body, and the core is filled with the first magnetic material.

3. 3. The inductor according to claim 1, wherein the total volume of the first magnetic material portion is 33 to 75% of the total volume of the second magnetic material portion.

4. 4. An inductor according to claim 1, wherein the coil is arranged on a support comprising a substrate of insulating or magnetic material.

5. The inductor according to claim 1 , further comprising an insulating film that covers the coil.

6. The coil includes a first coil and a second coil disposed on opposite sides of the support, the first and second coils have first and second lead portions exposed to the outside of the main body, respectively; The inductor according to claim 4 , wherein first and second external electrodes are disposed on the body so as to be connected to the first and second lead portions, respectively.

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