Apparatus and method for changing magnetic flux density and receiving wireless power

1. An apparatus for receiving wireless power from an apparatus for transmitting the wireless power, the apparatus for receiving the wireless power comprising:

a coil to receive the wireless power and wound to have a hollow portion; and

a metal member disposed within the hollow portion, that varies a magnetic flux density of the wireless power transmitting apparatus and is sensed by the apparatus for transmitting the wireless power by the variation of the magnetic flux density,

wherein the metal member includes a stainless steel plate,

wherein the coil includes any one of a winding coil structure and a lead frame coil structure, and

wherein a ratio of an area of the metal member to the hollow portion of the lead frame coil is in a range of 44% to 100%, and a ratio of an area of the metal member to the hollow portion of the winding coil structure is in a range of 22% to 50%.

2. The apparatus according to claim 1 , wherein the stainless steel plate is an alloy containing at least 8 wt % of chrome (Cr) and at least 75 wt % of iron (Fe).

3. The apparatus according to claim 1 , wherein the stainless steel plate is an alloy containing 16 wt % to 18 wt % of chrome (Cr) and at least 80 wt % of iron (Fe).

4. The apparatus according to claim 1 , wherein the stainless steel plate comprises STS430.

5. The apparatus according to claim 1 , wherein an intensity of a magnetic flux density of the stainless steel plate is at least 32 G (Gauss).

6. The apparatus according to claim 1 , wherein the stainless steel plate has a diameter in a range of 8 mm to 12 mm.

7. The apparatus according to claim 1 , wherein the winding coil structure includes a first coil and a second coil, and the first coil and the second coil are stacked.

8. The apparatus according to claim 7 , wherein the first coil is wound in such a manner that a diameter of the first coil becomes smaller from one end of the first coil corresponding to a predetermined number of windings, and an opposite end of the first coil is connected to one end of the second coil to allow the second coil to be wound in such a manner that a diameter of the second coil becomes increased corresponding to a predetermined number of windings.

9. The apparatus according to claim 8 , further comprising an insulation layer provided between the stacked first coil and the second coil, wherein the opposite end of the first coil and the one end of the second coil are connected by way of a through hole.

10. A method for receiving wireless power from an apparatus for transmitting the wireless power, the method comprising:

triggering a sensor of the wireless transmitting apparatus for transmitting the wireless power by a metal member in an apparatus for receiving the wireless power;

transmitting an effective signal to the apparatus for transmitting the wireless power;

receiving an identification signal from the apparatus for transmitting the wireless power; and

receiving the wireless power from the apparatus for transmitting the wireless power,

wherein the metal member varies a magnetic flux density of the wireless power transmitting apparatus and is sensed by a variation of the magnetic flux density, and

wherein the metal member includes a stainless steel plate.

11. The method according to claim 10 , wherein the stainless steel plate comprises an alloy containing at least 8 wt % of chrome (Cr) and at least 75 wt % of iron (Fe).

12. The method according to claim 10 , wherein the stainless steel plate comprises an alloy containing 16 wt % to 18 wt % of chrome (Cr) and at least 80 wt % of iron (Fe).

13. The method according to claim 10 , wherein the stainless steel plate comprises STS430.