Magnification and Microminiature Inspection

Abstract

Experienced and naive subjects used a binocular microscope to inspect microminiature patterns (O's) containing occasional defective elements (C's). Detection of defective elements was significantly affected by the level of magnification. The performance curves indicate the existence of a level of magnification which will minimize time per correct inspection. This optimum point occurs when the visual angle subtended by the magnified defect is between 9.0 and 12.0 minutes of arc. Both illumination and pattern size affect the absolute level of inspector performance, but the optimum performance point with respect to magnification does not appear to be affected by either.