Patent ID: 6867810

Claim:
A lens unit, comprising: a plurality of lens frames for holding an imaging optical system, said plurality of lens frames lying in a lens barrel and moving over a stowage interval between a position of stowage at which said lens frames are stowed and a ready-to-image position at which imaging is enabled, and over a zoom interval over which the ready-to-image position exists and a power varying action is executed; a stepping motor for moving said plurality of lens frames; and a driving control means for driving and controlling said stepping motor in a first driving mode during execution of a thrusting action for moving said plurality of lens frames from said position of stowage to said ready-to-image position or execution of a stowing action for moving said lens frames from any position within said zoom interval to said position of stowage, and for driving and controlling said stepping motor in a second driving mode, in which a lower current is used than in the first driving mode, during execution of a zooming action for moving said lens frames over said zoom interval, wherein said driving control means drives and controls said stepping motor according to a two-phase excitation method in said first driving mode and according to a single/two-phase excitation or micro-step driving method in said second driving mode, and wherein said driving control means drives and controls said stepping motor according to said two-phase excitation method when the power supply is turned off.