Light-emitting device

1. A light-emitting device comprising:

a casing comprising an opening;

a magnetic circuit comprising a magnetic gap;

a movable member comprising a coil that is electrically connectable to an alternating current power source and arranged in the magnetic gap of the magnetic circuit; and

a light source comprising a light-emitting diode and arranged above the movable member,

wherein the light source is positioned to close the opening above the movable member that is arranged in the casing, and

wherein the movable member is able to be activated with a voltage falling in a range of one to five percent of an entire voltage range that is applicable to the light-emitting device.

2. The light-emitting device according to claim 1 , further comprising:

a rectifier that is electrically connectable to the alternating current power source,

wherein the light source is electrically connected to the rectifier, and the rectifier is configured to rectify an alternating current originating from the alternating current power source to supply a rectified current to the light source.

3. The light-emitting device according to claim 1 ,

wherein the movable member further comprises a panel arranged on the coil.

4. The light-emitting device according to claim 1 ,

wherein the magnetic circuit comprises a yoke, a permanent magnet arranged in a recessed portion of the yoke, and a top plate arranged on the permanent magnet to form the magnetic gap between the top plate and the yoke.

5. The light-emitting device according to claim 3 , further comprising:

an air passage arranged below the light source and above the panel of the movable member.

6. A light-emitting device comprising:

a magnetic circuit comprising a magnetic gap;

a movable member comprising a coil that is electrically connectable to an alternating current power source and arranged in the magnetic gap of the magnetic circuit;

a light source comprising a light-emitting diode and arranged above the movable member; and

a magnetic fluid arranged on an outer peripheral side of the coil of the movable member,

wherein the movable member is able to be activated with a voltage falling in a range of one to five percent of an entire voltage range that is applicable to the light-emitting device.

7. A light-emitting device comprising:

a magnetic circuit comprising a magnetic gap;

a movable member comprising a coil that is electrically connectable to an alternating current power source and arranged in the magnetic gap of the magnetic circuit; and

a light source comprising a light-emitting diode and arranged above the movable member,

wherein the movable member is able to be activated with a voltage falling in a range of one to five percent of an entire voltage range that is applicable to the light-emitting device,

wherein the coil comprises a bobbin and a winding wire, a number of turns of the winding wire of the coil around an upper portion of the bobbin being more than a number of turns of the winding wire of the coil around a middle portion of the bobbin in a direction of up and down movement of the coil, and

wherein a number of turns of the winding wire of the coil around a lower portion of the bobbin is more than the number of turns of the winding wire of the coil around the middle portion of the bobbin in the direction of up and down movement of the coil.

8. The light-emitting device according to claim 7 , further comprising:

a magnetic fluid,

wherein the middle portion of the bobbin is exposed from the winding wire of the coil, and the magnetic fluid is positioned on the middle portion of the bobbin.

9. A light-emitting device comprising:

a casing comprising an opening;

a light source supported by the casing;

an air passage arranged adjacent to the light source;

a magnetic circuit comprising a yoke, a permanent magnet arranged in contact with the yoke, a top plate arranged on the permanent magnet to form a magnetic gap between the top plate and the yoke;

a movable member positioned below the light source in the casing and comprising a coil that is arranged in the magnetic gap; and

a magnetic fluid arranged on an outer peripheral side of the coil of the movable member.

10. The light-emitting device according to claim 9 ,

wherein the coil comprises a bobbin and a winding wire, a number of turns of the winding wire of the coil around an upper portion of the bobbin being more than a number of turns of the winding wire of the coil around a middle portion of the bobbin in a direction of up and down movement of the coil.

11. The light-emitting device according to claim 9 ,

wherein the coil comprises a bobbin and a winding wire, and

wherein a middle portion of the bobbin is exposed from the winding wire of the coil, and the magnetic fluid is positioned on the middle portion of the bobbin.

12. The light-emitting device according to claim 9 ,

wherein the movable member is able to be activated with a voltage falling in a range of one to five percent of an entire amount of voltage that is applicable to the light-emitting device.

13. A light-emitting device comprising:

a magnetic circuit comprising a yoke, a permanent magnet arranged in contact with the yoke, and a top plate arranged on the permanent magnet to form a magnetic gap between the top plate and the yoke;

a movable member comprising a coil to which an alternating current is supplied when the light-emitting device is activated;

a rectifier to which the alternating current is supplied when the light-emitting device is activated; and

a light source to which a rectified current rectified from the alternating current by the rectifier is supplied when the light-emitting device is activated,

wherein the coil of the movable member is configured to be supplied the alternating current before the alternating current is supplied to the rectifier, and

wherein the coil of the movable member is electrically positioned between an alternating current power source and the rectifier.

14. The light-emitting device according to claim 13 ,

wherein a first electrode of the light source is electrically connected to a first electrode of the rectifier, and a second electrode of the light source is electrically connected to a second electrode of the rectifier.

15. The light-emitting device according to claim 13 ,

wherein the rectifier is electrically connected to the coil of the movable member, the alternating current power source, and the light source.

16. The light-emitting device according to claim 13 ,

wherein the rectifier is a bridge rectifier.

17. The light-emitting device according to claim 13 ,

wherein the movable member is able to be activated with a voltage falling in a range of one to five percent of an entire amount of voltage that is applicable to the light-emitting device.