Apparatus for positioning a thin plate

摘要

A positioning apparatus includes: a stage having a flat placement surface on which a thin plate is mounted. The placement surface has a flat region which is slightly larger than and completely covers that of said thin plate. The placement surface also has lateral side edges. An optical detecting means is arranged above the stage for detecting a mark provided on the thin plate and has such a view that the mark can be caught by the view if the thin plate placed on the placement surface is within the flat region, but the mark cannot be caught by the view if the thin plate placed on the placement surface protrudes by a part thereof from the region of the placement surface. A movable part pushes the thin plate until it comes into contact with the lateral edge to move the thin plate so that the thin plate is brought within the flat region of the placement surface.