Power acquisition device and power acquisition method

A power acquisition device to be fixed to an illuminating device having a fluorescent tube and a reflective plate so as to acquire power from a magnetic field generated by an alternating current flowing through the fluorescent tube by electromagnetic induction, wherein

• the power acquisition device is fixed to surround all outer circumference of the fluorescent tube, and
• at least either a thickness of the power acquisition device in the direction perpendicular to the surface of the fluorescent tube or a length of the power acquisition device in the direction parallel to the length direction of the fluorescent tube is non-uniformly, wherein
• when the area where the reflective plate exists in the direction perpendicular to the surface of the fluorescent tube is a first area;
• and the area where the reflective plate does not exist in the direction perpendicular to the surface of the fluorescent tube is a second area,
• the length of the power acquisition device in the direction parallel to the length direction of the fluorescent tube in at least a part of the first area is larger than the maximum value of the length of the power acquisition device in the direction parallel to the length direction of the fluorescent tube in the second area.

A power acquisition method of a power acquisition device to be fixed to an illuminating device having a fluorescent tube and a reflective plate so as to acquire power from a magnetic field generated by an alternating current flowing through the fluorescent tube by electromagnetic induction, wherein

• the power acquisition device is fixed to surround the fluorescent tube, and
• at least either a thickness of the power acquisition device in the direction perpendicular to the surface of the fluorescent tube or a length of the power acquisition device in the direction parallel to the length direction of the fluorescent tube is non-uniformly, and wherein
• when the area where the reflective plate exists in the direction perpendicular to the surface of the fluorescent tube is a first area;
• the area where the reflective plate does not exist in the direction perpendicular to the surface of the fluorescent tube is a second area;
• the minimum distance between the surface of the fluorescent tube and reflective plate in the first area is distance D3;
• and the thickness of the power acquisition device in the direction perpendicular to the surface of the fluorescent tube at the position at which the distance between the surface of the fluorescent tube and the reflective plate in the first area becomes minimum is thickness D1,
• the thickness Dl is smaller than the distance D3, and the thickness of the power acquisition device in the direction perpendicular to the surface of the fluorescent tube in at least a part of the second area is set to thickness D2 which is larger than the distance D3.