Abstract: An electromagnetic actuator has a large driving force and a good response speed and an image pickup apparatus obtains an image of a high resolution even by using a solid state image pickup device with a small number of pixels. The actuator comprises permanent magnetic field generating units for generating permanent magnetic fields and a current path forming unit which is relatively movable for the permanent magnetic field generating units and forms a current path which crosses the permanent magnetic fields by a current according to an input control signal. The permanent magnetic field generating units of the actuator generate two permanent magnetic fields in the directions which cross each other by, for example, two pairs of magnets. The current path forming unit has two coils each crossing the permanent magnetic field and winding shafts of those coils exist almost on the same line.

Abstract: A projector in which light emitted from a light source is made incident upon a transmission type picture panel and is projected onto a screen through a projection lens system having a condenser lens and an imaging lens. The condenser lens and the imaging lens are relatively movable with respect to the transmission type picture panel in an optical axis direction. Thus, when a projection distance from the projection lens system to the screen is varied, both the condenser lens and the imaging lens are relatively moved, with respect to the transmission type picture panel, to adjust a focus of the emitted light on the screen. A focusing method for the projector is also provided.