Patent Application
20180218822
This application claims benefit of priority to Japanese Patent Application No. 2017-013268, filed Jan. 27, 2017, the entire content of which is incorporated herein by reference.
The present disclosure relates to a layered electronic component.
Multilayer inductors stacking insulation layers and conductor patterns in which the conductor patterns between the insulation layers are connected in spiral form and are superimposed in the stacking direction within a multilayer body to form a circling coil have been known. According to the progress of down-sized mobile equipment with enhanced performances, a demand for smaller and thinner multilayer inductors has increased. In addition, equipment driving with small voltage requires the multilayer inductors to have improved DC superposition characteristics and low loss.
The layered electronic component according to Japanese Unexamined Patent Application Publication No. 2016-051752 includes metallic magnetic material layers formed by using metallic magnetic material particles, conductor patterns forming a coil in the multilayer body by connecting each other in spiral form, and glass based nonmagnetic materials arranged between the conductor patterns. The above structure enables the layered electronic component to achieve both high DC superposition characteristics and low loss.
Producing a layered electronic component by heating metallic magnetic materials with glass ingredient being mixed has a risk to cause characteristics degradation due to diffusion of the glass ingredient in the metallic magnetic materials in some cases. An object according to the present disclosure is to provide a layered electronic component including metallic magnetic materials which suppresses characteristics degradation in manufacturing and can achieve both high DC superposition characteristics and low loss.
According to a preferred embodiment of the present disclosure, a layered electronic component includes a multilayer body having metallic magnetic material layers including metallic magnetic material particles and a coil being built in the multilayer body. The coil is formed of multiple conductor patterns spirally connected each other and stacked along a winding axis direction of the coil, and the multilayer body includes nonmagnetic ferrite parts arranged at least an inner area of the coil when viewed from the winding axis direction of the coil.
Other features, elements, characteristics and advantages of the present disclosure will become more apparent from the following detailed description of preferred embodiments of the present disclosure with reference to the attached drawings.
A layered electronic component includes a multilayer body having metallic magnetic material layers including metallic magnetic material particles and a coil being built in the multilayer body. The coil is formed of multiple conductor patterns spirally connected each other and stacked along a winding axis direction of the coil. The multilayer body includes nonmagnetic ferrite parts arranged at least at an inner area of the coil when viewed from the winding axis direction of the coil. As described above, layered electronic components use a metallic magnetic material with high maximum magnetic flux density in the multilayer body and form a magnetism gap at least at a part of a magnetic path in the multilayer body by a nonmagnetic ferrite part. The nonmagnetic ferrite part enables a layered electronic component to control the magnetic flux from the coil and the multilayer body to be hard to be magnetically saturated. The above enables a layered electronic component to achieve both high DC superposition characteristics and low loss and to further suppress lowering withstand voltage and inductance. In addition, since glass is not used for the structure of the multilayer body, lowering withstand voltage and inductance can be suppressed. Since higher inductance allows a shorter conductor pattern, direct current resistance (DCR) is lowered and thus power loss can be lowered.
The nonmagnetic ferrite parts formed in the multilayer body are arranged at the inner area of the coil when viewed from the winding axis direction of the coil to intersect the magnetic flux generated by the coil and passing through inside the coil. The nonmagnetic ferrite part may be arranged at least at an inner side of the coil or on an extending area thereof. That is, the ferrite part may be arranged inside the coil or may be circumscribed to at least one end portion of the coil.
The nonmagnetic ferrite part has a substantially layered shape and is orthogonal to the winding axis direction of the coil, and an outer peripheral part of the nonmagnetic ferrite part may be exposed to the surface of the multilayer body. This makes it possible to effectively control the magnetic flux of the coil and to achieve higher DC superposition characteristics.
The nonmagnetic ferrite part may be arranged across the coil. This makes it possible to effectively control the magnetic flux of the coil and to achieve higher DC superposition characteristics. A nonmagnetic ferrite part may be further arranged between the stacked conductor patterns. This makes it possible to achieve excellent withstand voltage.
The volume average particle diameter of the metallic magnetic material particles may be larger than the distance between stacked conductor patterns. This makes it possible to achieve higher DC superposition characteristics and withstand voltage. Further, since the distance between each conductor pattern can be short, smaller and thinner layered electronic component can be configured.
The nonmagnetic ferrite part may be arranged to touch at least one end portion of the coil. This makes it possible to effectively control the magnetic flux of the coil and to achieve higher DC superposition characteristics.
Embodiments of the present disclosure will be explained below according to the drawings. However, embodiments described below merely illustrate examples of layered electronic components for realizing the technical idea of the present disclosure, and the present disclosure does not limit layered electronic components illustrated below. Note that members illustrated in aspects of the present disclosure are never limited to the members illustrated in the embodiments. Especially, the size, material, shape and relative arrangement and the like of structure components according to the embodiments do not limit the scope of the present disclosure otherwise specifically noted, and merely illustrate examples for the explanation. Identical reference signs are used for the identical portions in each drawing. Although, disclosed embodiments are divided and explained for the sake of the explanation or clarity, partial replacement or combination of configurations disclosed in the different embodiments is possible.
The multilayer body 11 is formed by stacking metallic magnetic material layers, the conductor patterns 12A to 12E, and the nonmagnetic ferrite parts 13A to 13D. The metallic magnetic material layers are formed by using metallic magnetic material particles such as metallic magnetic alloy powder including iron and silicon, metallic magnetic alloy powder including iron, silicon and chromium, and metallic magnetic alloy powder including iron, silicon and an element easy to be oxidized than iron. The volume average particle diameter of the metallic magnetic material particles can be larger than the distance between stacked conductor patterns, for example.
The conductor patterns 12A to 12E forming the coil, for example, are formed by using conductor paste including conductive metallic materials in paste form such as silver, silver-based alloy, gold, gold-based alloy, copper, and copper-based alloy, etc. In
The multilayer body 11 formed by stacking the metallic magnetic material layers, conductor patterns, and the nonmagnetic ferrite parts is debindered in the atmosphere at a predetermined temperature (for example, about 350° C.) and fired (for example, about 750° C. in the atmosphere). Glass is used in place of the nonmagnetic ferrite in the known art. In the above case, a softening point of glass need to be at equal to or lower than the firing temperature to secure the strength for forming a structure body (for example, in the case of the firing temperature being about 750° C., a softening point being about 720° C.). Consequently, diffusion of glass ingredient from boundary surface of glass which is contacting to the metallic magnetic material particles cannot be avoided. The diffusion of glass ingredient to the metallic magnetic material particles can cause lowering insulation characteristics and generating characteristics degradation. On the contrary, in a case of using the nonmagnetic ferrite instead of the glass ingredient, unnecessary diffusion of ingredient in the firing process does not occur, and thus characteristics degradation is suppressed.
Outer terminals 14A and 14B are formed at both end surfaces of the multilayer body 11. Each of both end portions of the coil is connected to each of both of the outer terminals 14A and 14B. The outer terminals 14A and 14B can be formed after the firing process of the multilayer body 11, for example. In the above case, for example, the outer terminals 14A and 14B can be formed by baking (for example, about 650° C.) the multilayer body 11 after applying conductor paste for the outer terminal to both end portions of the multilayer body 11. Further, the outer terminals 14A and 14B can be formed by plating the baked conductors formed by baking the multilayer body 11, after applying conductor paste for the outer terminal to both the end portions of the multilayer body 11. In the above case, hollows present in the multilayer body 11 may be impregnated with resin in advance to prevent intrusion of a plating solution.
The multilayer body 21 is formed by stacking metallic magnetic material layers, the conductor patterns 22A to 22E, and nonmagnetic ferrite parts 23A to 23D. The metallic magnetic material layers are formed by using metallic magnetic material particles such as metallic magnetic alloy powder including iron and silicon, metallic magnetic alloy powder including iron, silicon and chromium, and metallic magnetic alloy powder including iron, silicon and an element easy to be oxidized than iron. The volume average particle diameter of the metallic magnetic material particles can be larger than the distance between stacked conductor patterns, for example.
The conductor patterns 22A to 22E forming the coil, for example, are formed by using conductor paste including conductive metallic materials in paste form such as silver, silver-based alloy, gold, gold-based alloy, copper, copper-based alloy, etc. In
Outer terminals 24A and 24B are formed at both the end surfaces of the multilayer body 21. Each of both the end portions of the coil is connected to both of the outer terminals 24A and 24B. The forming method of the outer terminals 24A and 24B is similar to that of the first example.
The multilayer body 31 is formed by stacking metallic magnetic material layers, the conductor patterns 32A to 32E, and the nonmagnetic ferrite parts 33A and 33B. The metallic magnetic material layers are formed by using metallic magnetic material particles such as metallic magnetic alloy powder including iron and silicon, metallic magnetic alloy powder including iron, silicon and chromium, and metallic magnetic alloy powder including iron, silicon and an element easy to be oxidized than iron.
The conductor patterns 32A to 32E forming the coil, for example, are formed by using conductor paste including conductive metallic materials in paste form such as silver, silver-based alloy, gold, gold-based alloy, copper, copper-based alloy, etc. In
The layered electronic component of the present disclosure is compared with a comparative example having an identical structure state and designed to be initial inductance value being 1 μH (for example, a known layered electronic component using alumina and glass according to Japanese Unexamined Patent Application Publication No. 2016-051752). The results are illustrated in
Although examples of the layered electronic component according to the present disclosure are described thus far, the present disclosure is not limited to the examples. For example, the metallic magnetic material layers may be formed using such as metallic magnetic alloy powder including iron and silicon, or metallic magnetic alloy powder including iron, silicon and chromium, by being doped with an element easy to be oxidized than iron. Further, thickness, position, and the number of the nonmagnetic ferrite parts can be changed according to the desired characteristics.
While preferred embodiments of the disclosure have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the disclosure. The scope of the disclosure, therefore, is to be determined solely by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2017-013268 | Jan 2017 | JP | national |
