US 5,317,338 A · Visual measurement technique and test pattern for aperture offsets in photoplotters

Abstract

A test pattern including an aperture image and a line image including a plurality of parallel lines, forming a measurement graticule, overlapping the aperture image, permits determination of dimensions for correction of alignment of image centerlines by inspection rather than complex measurement with stationary optical instruments. Since the line pattern preferably includes a plurality of parallel lines of predetermined width and separated by a predetermined spacing, the line image can be made to overlie the aperture image without obscuring features of the aperture image which are significant to determination of the alignment correction dimension.

Claims6

Dependent claims

A method of operating a photoplotter having a line side and an aperture side for respectively forming line images and aperture images, said method including the steps of

forming an aperture image having a centerline,
forming a test pattern image overlapping said aperture image, said test pattern image including a measurement graticule having a centerline,
determining the distance from said centerline of said measurement graticule to said centerline of said aperture image from said measurement graticule, and
controlling said photoplotter to superimpose said centerline of said aperture image on a centerline of an image produced by said line side of said photoplotter which corresponds to said centerline of said test pattern image.

1 more element

Dependencies are inferred from the claim text.

Visual measurement technique and test pattern for aperture offsets in photoplotters

Life of this patent

Visual measurement technique and test pattern for aperture offsets in photoplotters

Life of this patent

Abstract

Claims6