Image Number 5 for United States Patent #7580203.
A lens assembly has an image pickup device incorporated therein, and includes a zoom lens for passage of light to the image pickup device. A cam mechanism moves the zoom lens along an optical axis. The cam mechanism includes a rotatable zoom ring for zooming operation by rotating about the optical axis. There are an intake vent for air flow from an outside to an inner space, and an exhaust vent for air flow from the inner space to the outside. Plural fan blades are formed to project from the zoom ring, for propelling the air in the inner space upon the rotation for zooming, to dissipate heat by air flow. The fan blades are inclined relative to a rotational direction of the zoom ring. Furthermore, an air filter is porous and air permeable, secured inside each of the intake vent and the exhaust vent.