Patent ID: 6798987
Filing Date: 2004-09-28
Classification: G03B

Abstract:
A driving apparatus comprising:a rotor rotatable about a rotational axis and having a cylindrical magnet portion whose outer circumferential surface are divided along a circumferential direction into a plurality of differently magnetized portions; at least an outer magnetic pole portion formed extending in a direction parallel to said rotational axis of said rotor, and facing said outer circumferential surface of said magnet portion; an inner magnetic pole portion formed opposingly to said outer magnetic pole portion, and facing an inner circumferential surface of said magnet portion; and a coil for magnetically exciting said outer magnetic pole portion and said inner magnetic pole portion, said coil being arranged along a direction of said rotational axis of said rotor; wherein said rotor can be selectively held at one of three stop positions, and a condition of âˆ’0.3X+0.72