Patent ID: 6087749
Filing Date: 2000-07-11
Classification: G02B,H02K

Abstract:
A rotary polygonal mirror driving apparatus comprising:a rotor to which a driving magnet is attached;a stator disposed opposite said driving magnet;a rotary polygonal mirror having a center hole through which a portion of said rotor is inserted so that it is mounted on a mirror mounting portion of said rotor;a cap fixed to said rotor so that said rotary polygonal mirror is pushed in a thrust direction to be fixed onto said rotor;and a top annular groove and a bottom annular groove concentric with said center hole, which are cut in top and bottom surfaces in a mutually overlapping area radially further out than said mirror mounting portion of said rotor;and wherein said cap has an engaging protrusion projected toward said rotary polygonal mirror and engaging with said top annular groove, said engaging protrusion contacting at least an inner side wall of said top annular groove.