The present invention discloses a power inductor encapsulated through injection molding. The power inductor comprises a coil winding, a soft magnetic ferrite middle column inserted in a middle of the coil winding, and a magnetic powder glue for encapsulating the coil winding and the soft magnetic ferrite middle column through injection molding. The power inductor is square and meets L≧W and 2rc>0.4×2W, wherein a section width of the soft magnetic ferrite middle column perpendicular to a height direction of the inductor is 2rc, a length of the power inductor is 2L, and a width of the power inductor is 2W. According to the present invention, a balanced direct-current resistance and a direct-current superposition saturation characteristic can be obtained, and the direct-current resistance is greatly decreased while an excellent direct-current superposition saturation characteristic is ensured.

A coil component includes a support substrate, a coil portion including a first conductive layer being in contact with one surface of the support substrate, and a second conductive layer disposed on the first conductive layer to be spaced apart from the one surface of the support substrate, and a body including the support substrate and the coil portion embedded in the body. One side of the first conductive layer is closer to a center of the second conductive layer in a width direction of the coil portion than one side of the second conductive layer.

A coil component includes a body and a coil conductor embedded in the body. The body includes a magnetic layer and a non-magnetic layer. The magnetic layer is formed of a composite material including a metal particle and a resin material, and the non-magnetic layer is arranged to block between at least one of top and bottom surfaces of the body and the coil conductor.

A surface-mounted inductor including a coil having a wound part formed by winding a conductive wire and extended parts extended from an outer circumference of the wound part, a molded body containing the coil, constituted by a composite material containing a magnetic powder, and outer terminals connected to end portions of the extended parts disposed on a mounting surface. The wound part is contained within the molded body so that a winding axis is parallel to the mounting surface. The extended parts are extended toward the mounting surface side, each end portion of the extended parts are exposed from the surface thereof of the molded body. In the molded body, a density of a magnetic powder between the end portions of the extended parts on the mounting-side surface is lower than a density in the surface on the opposite side from the mounting surface.

A dust core includes large particles having an average particle size of 8-15 μm, medium particles having an average particle size of 1-5 μm, and small particles having an average particle size of 300-900 nm when a cross section thereof is observed. An area ratio occupied by the large particles is 50% to 90%, an area ratio occupied by the medium particles is 0% to 30%, and an area ratio occupied by the small particles is 5% to 30%, when a total area ratio occupied by the large particles, the medium particles and the small particles is 100% in the cross section. Vickers hardness (Hv) of the large particles, the medium particles and the small particles is 150-600 respectively. The small particles are alloy powder containing Fe and at least Si or N. The dust core may be included in an inductor element.

An upper end portion and a lower end portion of a second magnetic portion of a coil component are further away from a coil than when a third part and a fifth part are not present. For this reason, a magnetic flux is unlikely to be concentrated in the upper end portion and the lower end portion of the second magnetic portion, so that magnetic saturation is unlikely to occur. Therefore, improvement of direct current superimposition characteristics is realized in the coil component.

Disclosed herein is a coil component that includes: a coil part having a structure in which alternately stacking a plurality of conductor layers each including a spiral coil pattern and a plurality of insulating layers; a first magnetic layer disposed in an inner diameter area of the coil part, in an outside area of the coil part, and on one side in an axial direction of the coil part; and a second magnetic layer disposed on other side in the axial direction of the coil part. Each of the first and second magnetic layers comprises a composite magnetic material containing magnetic fillers and binder resin. The content of the magnetic filers in the first magnetic layer is higher than the content of the magnetic fillers in the second magnetic layer.

A ferromagnetic-polymer composite material comprises a polymer and a plurality of ferromagnetic film platelets disposed in the polymer. Each ferromagnetic film platelet comprises first and second insulator layers and a ferromagnetic layer disposed between the first and second insulator layers. The ferromagnetic layer can be magnetically anisotropic in which a hard axis of magnetization is aligned parallel to a plane that passes through and parallel to an interface between the first insulator layer and the ferromagnetic layer. The easy and/or hard axes of magnetization in the ferromagnetic film platelets can be aligned. An inductor can have a core formed of the ferromagnetic-polymer composite material.

In a coil component, fixing strength of an external terminal is improved. In the coil component, on the end face of the element body, the center position of the external terminal electrode in the first direction is biased toward the center position of the end face with respect to the center position of the outer end portion. Therefore, the fixing area between the external terminal electrode and the element body is increased on the center position side of the end face, and thus fixing strength between the external terminal electrode and the element body is improved.

In a coil component, coupling coefficient is improved. In the coil component, the coupling position between the outer end portion of the first planar coil and the first lead-out portion is biased toward the second lead-out portion with respect to the center line of the first lead-out portion, whereby the length of the second planar coil not alongside with the outermost turn of the first planar coil is shortened. By shortening the length of the second planar coil, the coupling coefficient between the first coil portion and the second coil portion is increased.