Patent ID: 7020348

Claim:
A device for exposing a mask pattern onto a workpiece, comprising: a first and second means for edge determination which are located at two locations in a transport direction of the strip-shaped workpiece and which produce signals indicative of transverse positioning of an edge of a strip-shaped workpiece, and which each have an image collection means for photographing the edge of the strip-shaped workpiece; a first mask which is located in a visual field of the image collection means of the first means for edge determination and which has a linear part which, in use, intersects the edge of said workpiece; a second mask which is located in the visual field of the image collection means of the second means for edge determination and which has a linear part which, in use, intersects the edge of said workpiece; an image processing part for processing the signals from the first means for edge determination and the second means for edge determination, comparing photographed images from the image collection means to a pre-recorded registration pattern and determining position coordinates of the edge of the workpiece; a controller for computing an amount of meander of the strip-shaped workpiece based on the position coordinates of the edge of the workpiece at two locations which have been determined based on the images of the edge which have been photographed by the first means for edge determination and the second means for edge determination, and for outputting a control signal when the computed amount of meander is greater than a preset amount of meander; and a means for correcting the meander of the strip-shaped workpiece according to the above described control signal.