Sheet for shielding against electromagnetic waves and wireless power charging device
A sheet for shielding against electromagnetic waves and a wireless power charging device are provided. The sheet for shielding against electromagnetic waves includes a plurality of magnetic layers and an adhesive layer interposed between the plurality of magnetic layers and forming chemical bonds with an adjacent magnetic layer.
1. A sheet for shielding against electromagnetic waves, the sheet comprising:
a plurality of magnetic layers including silicon (Si); and
an organosilane layer interposed between the plurality of magnetic layers, and directly bonded with two of the plurality of magnetic layers by silicon-oxygen bonds,
wherein the sheet has a thickness of 1 μm or less.
2. The sheet of claim 1 , wherein the plurality of magnetic layers includes a metal ribbon.
3. The sheet of claim 1 , wherein the plurality of magnetic layers includes an Fe—Si—B alloy.
4. The sheet of claim 3 , wherein: in the Fe—Si—B alloy,
a content of Fe is between 70 and 90 atomic %; and
a sum of the content of silicon (Si) and boron (B) is between 10 and 30 atomic %.
5. The sheet of claim 4 , wherein in the Fe—Si—B alloy, a content of chromium (Cr) or cobalt (Co) is greater than 0 and less than or equal to 20 atomic %.
6. The sheet of claim 1 , wherein silicon (Si) of the two of the plurality of magnetic layers and oxygen of the organosilane layer forms the silicon-oxygen bonds.
7. The sheet of claim 1 , wherein a magnetic layer among the plurality of magnetic layers includes a plurality of fragments.
8. The sheet of claim 7 , wherein the organosilane layer fills spaces between the plurality of fragments.
9. A wireless power charging device comprising:
a coil unit; and
an electromagnetic wave blocking sheet disposed between the coil unit and an external battery, and including:
a plurality of magnetic layers including silicon (Si); and
an organosilane layer interposed between the plurality of magnetic layers, and directly bonded with two of the plurality of magnetic layers by silicon-oxygen bonds,
wherein the sheet has a thickness of 1 μm or less.
10. The wireless power charging device of claim 9 , wherein the plurality of magnetic layers includes a metal ribbon.
11. The wireless power charging device of claim 9 , wherein the plurality of magnetic layers includes an Fe—Si—B alloy.
12. The wireless power charging device of claim 9 , wherein silicon (Si) of the two of the plurality of magnetic layers include silicon (Si) and oxygen of the organosilane layer forms the silicon-oxygen bonds.
13. The wireless power charging device of claim 9 , wherein a magnetic layer among the plurality of magnetic layers includes a plurality of fragments.
14. The wireless power charging device of claim 13 , wherein the organosilane layer fills spaces between the plurality of fragments.