Apparatus protecting a lens from airborne particulates

Abstract

During scribing of a ceramic plate with a laser beam, ceramic particles rise from the workpiece in a direction of motion that is generally the same as that of the workpiece. The lens on a laser scriber is protected from abrasive contact with such particulates in the atmosphere by slipping the base of a housing over the circumference of the lens mount and forming a generally airtight seal between them. The housing is shaped like a frustum of a right circular cone, with the apex end thereof truncated and essentially rolled over to form an orifice through which the lens axis and laser beam pass. A plurality of streams of pressurized air are introduced into the housing near the midpoint of the frustum and the lens surface. The air streams are introduced tangent to the inner surface of the housing and angled downward for producing a vortex of air that is exhausted to the atmosphere through the orifice at a velocity and vorticity that inhibits particulates outside of the cover entering the orifice. A suction hose is located in front of the housing for removing particulates from this area. In an alternate embodiment, a directional air lock door is established in front of the lens, with the airstream that establishes the door being directed into a suction hose. The direction of this airstream is preferably maintained the same as the direction that the workpiece moves.