Vibration generator moving vibrator by magnetic field generated by coil and holder used in vibration-generator

1. A vibration generator comprising:

a chassis;

a vibrator including a single magnet;

a holder, which is attached to said chassis; and

a coil for generating a magnetic field in order to change at least one of a position and an attitude of said vibrator with respect to said chassis, said coil being a low-profile coil in which a size in a winding axis direction is smaller than that in a first direction orthogonal to said winding axis direction, said coil being an air core coil,

the vibration generator as a whole having a low-profile, substantially-rectangular shape such that a size of the vibration generator as a whole in the winding axis direction of the coil is smaller than that in the first direction orthogonal to said winding axis direction and smaller than that in a second direction orthogonal to said winding axis direction, the first direction being different from the second direction, wherein

said holder includes

a vibrator retention unit retaining said vibrator, the vibrator retention unit having an aperture formed by a plurality of inner walls of the vibrator retention unit, and the single magnet being disposed in the aperture such that the single magnet contacts all of the inner walls;

a fixed unit being fixed to said chassis; and

an arm connecting said fixed unit and said vibrator retention unit, said arm supporting said vibrator retention unit while said vibrator retention unit can be displaced with respect to said fixed unit, wherein

said fixed unit, said arm, and said vibrator retention unit are integrally molded using resin,

said fixed unit includes a hole unit in which a projection provided in said chassis is fitted,

said hole unit has a bottomed cylindrical shape,

said holder retains said vibrator while said vibrator can be displaced with respect to said chassis,

said coil has a planar shape approximately parallel to a horizontal plane,

said vibrator has a plate shape approximately parallel to said horizontal plane,

a largest surface of said coil is disposed facing a largest surface of said vibrator, and

said arm is formed such that said vibrator reciprocates in a movement direction approximately parallel to said horizontal plane in response to excitation of said coil, the movement direction being parallel to the second direction.

2. The vibration generator according to claim 1 , wherein

said coil includes two coils,

said two coils are provided so as to be adjacent to each other in the movement direction of said vibrator, and

said vibrator moves in said movement direction as currents having different orientations are passed through said two coils to excite said coils.

3. The vibration generator according to claim 1 , further comprising

a bottom plate being attached to said chassis, said bottom plate being disposed in a position further away from said coil with respect to said vibrator, wherein

said bottom plate is made of a nonmagnetic material.

4. The vibration generator according to claim 3 , further comprising

a circuit board being disposed along said bottom plate, wherein

said coil is connected to said circuit board.

5. The vibration generator according to claim 4 , wherein

said circuit board is a flexible printed board,

a notch is partially formed in a rim portion of said bottom plate, and

said circuit board is folded back at said notch and disposed so as to partially cover double sides of said bottom plate.

6. The vibration generator according to claim 1 , wherein

said vibrator includes a yoke that is of a magnetic plate,

said yoke is disposed such that one surface of said yoke is opposite an inner surface of said chassis, and

said yoke includes a projection projecting from said one surface toward said inner surface of said chassis.

7. The vibration generator according to claim 6 , wherein

said projection includes a plurality of projections, and

at least two of said projections are provided so as to be symmetrical with respect to a plane perpendicular to the movement direction of said vibrator.

8. The vibration generator according to claim 6 , wherein

a surface of said projection has a curved shape that is convex toward said inner surface of said chassis.

9. A holder, which is used while attached to a chassis of a vibration generator that moves a vibrator to generate a vibration, comprising:

a vibrator retention unit retaining said vibrator;

a fixed unit being fixed to said chassis; and

an arm connecting said fixed unit and said vibrator retention unit, said arm supporting said vibrator retention unit while said vibrator retention unit can be displaced with respect to said fixed unit, wherein

said fixed unit, said arm, and said vibrator retention unit are integrally molded using resin,

said fixed unit includes a hole unit in which a projection provided in said chassis is fitted, and

said hole unit has a bottomed cylindrical shape.

10. The holder according to claim 9 , wherein

said fixed unit, said arm, and said vibrator retention unit are integrally molded using an elastic material.

11. The holder according to claim 9 , wherein

said hole unit is made such that a direction perpendicular to a movement direction of said vibrator is a depth direction.

12. The holder according to claim 9 , wherein

a slit is formed in said arm.

13. The holder according to claim 12 , wherein

said slit is formed along a lengthwise direction of said arm.

14. The holder according to claim 12 , further comprising

a reinforcing plate being inserted in said slit, said reinforcing plate being bent together with said arm as said vibrator retention unit is displaced with respect to said fixed unit.

15. The holder according to claim 9 , wherein

said arm is molded in two colors.

16. The holder according to claim 15 , wherein,

in said arm, an outside of a portion made of a first resin is covered with a second resin having hardness lower than that of said first resin.

17. The holder according to claim 9 , wherein

said vibrator includes a weight, and

said weight is attached to said vibrator retention unit.

18. The holder according to claim 9 , wherein

said vibrator is formed together with said holder by insert molding, thereby attaching said vibrator to said vibrator retention unit.

19. The holder according to claim 9 , wherein

said projection fitted in said hole unit is vertically provided in said chassis.

20. The holder according to claim 19 , wherein

said projection has a columnar shape.

21. The holder according to claim 9 , wherein

said fixed unit is a pillar body,

said chassis includes an engaging unit engaging said pillar body, and

said engaging unit includes a plurality of claws, said claws grip a side circumferential surface of said pillar body.