Magnetic sheet and wirelessly charged magnetic member including same
An embodiment of the present invention relates to a magnetic sheet having both an electromagnetic field shielding function and a heat dissipating function, and to a wirelessly charged magnetic member using same.
1. A magnetic sheet comprising:
a thin film formed from a base substrate composition including a binder resin and a plurality of particles of Fe-based alloy magnetic powder having a width-direction length (X) longer than a thickness-direction length (Y),
wherein a proportion of the particles of the magnetic powder oriented to have an angle (θ) with respect to total number of the particles of the magnetic powder is in a range of 30%˜99%, the angle being formed by an extension line of a cross section of each of the particles of the magnetic powder in a horizontal direction and an extension line of a horizontal plane of the base substrate wherein the angle is an acute angle, an obtuse angle or a straight angle,
wherein the plurality of particles of the magnetic powder in the base substrate has an apparent density of 0.2˜0.8 g/cm 3 ,
wherein the magnetic sheet is configured such that the base substrate has a thermal conductivity (Ta) in the width direction greater than a thermal conductivity (Tb) in the thickness direction,
wherein a ratio (Ta:Tb) of the thermal conductivity (Ta) in the width direction and the thermal conductivity (Tb) in the thickness direction is in a range of (5˜1.5):1,
wherein the thermal conductivity (Ta) in the width direction is in a range of 3 W/m·k to 10 W/m·k, and
wherein the Fe-based alloy comprises Si having a content by weight in a range of 1%-16%.
2. The magnetic sheet of claim 1 , wherein the magnetic powder satisfies a relationship in which an angle formed between an extension line (X 2 ) in the width-direction (X) of the particles of the magnetic powder and the extension line of the horizontal plane of the base substrate is in a range of 30° ˜60° at a central point (X 1 ) that is a center of the width-direction length (X) of the particles of the magnetic powder.
3. The magnetic sheet of claim 1 , wherein the plurality of particles of the magnetic powder satisfies a relationship in which a ratio of the width-direction length (X) and the thickness-direction length (Y) is in a range of (3˜80):1.
4. The magnetic sheet of claim 3 , wherein an average width-direction length (X) of the particles of the magnetic powder is in a range of 10˜100 μm.
5. The magnetic sheet of claim 1 , wherein the binder resin comprises at least one selected from the group consisting of a polyvinyl alcohol-based resin, a silicon-based resin, an epoxy-based resin, an acrylate-based resin, a urethane-based resin, a polyamide-based resin, and a polyimide-based resin.
6. The magnetic sheet of claim 5 , wherein a blending ratio of the magnetic powder and the binder resin is in a range of 70:30˜95:5 (based on weight).
7. A wirelessly charged magnetic member comprising:
two or more stacked magnetic sheets,
wherein each of the magnetic sheets comprises a thin film formed from a base substrate composition including a binder resin and a plurality of particles of Fe-based alloy magnetic powder having a width-direction length (X) longer than a thickness-direction length (Y),
wherein a proportion of the particles of the magnetic powder oriented to have an angle (θ) with respect to total number of the particles of the magnetic powder is in a range of 30%˜99%, the angle being formed by an extension line of a cross section of each of the particles of the magnetic powder in a horizontal direction and an extension line of a horizontal plane of the base substrate wherein the angle is an acute angle, an obtuse angle or a straight angle,
wherein the plurality of particles of the magnetic powder in the base substrate has an apparent density of 0.2˜0.8 g/cm 3 ,
wherein the thermal conductivity (Ta) in the width direction is in a range of 3 W/m·k to 10 W/m·k,
wherein a ratio (Ta:Tb) of the thermal conductivity (Ta) in the width direction and the thermal conductivity (Tb) in the thickness direction is in a range of (5˜15):1, and
wherein the Fe-based alloy comprises Si having a content by weight in a range of 1%-16%.
8. The wirelessly charged magnetic member of claim 7 ,
wherein the magnetic powder satisfies a relationship in which the angle formed between an extension line (X 2 ) in the width-direction (X) of the particles of the magnetic powder and the extension line of the horizontal plane of the base substrate is in a range of 30° ˜60° at a central point (X 1 ) that is a center of the width-direction length (X) of the particles of the magnetic powder.
9. The wirelessly charged magnetic member of claim 7 ,
wherein an average width-direction length (X) of the particles of the magnetic powder is in a range of 10˜100 μm, and
wherein the plurality of particles of the magnetic powder satisfies a relationship in which a ratio of the width-direction length (X) and the thickness-direction length (Y) is (3˜80):1.
10. The wirelessly charged magnetic member of claim 7 , wherein a blending ratio of the magnetic powder and the binder resin is in a range of 70:30˜95:5 (based on weight).