| 摘要 |
<p>Apparatus for precisely measuring the location of points on working media, such as a PCB, includes: a base panel (18) having a surface area at least equal to that of the largest working medium (16) to be measured, a reference mark, and a grid of fiducial marks each located at precisely-known locations with respect to the reference mark; a coarse positioning device (Ccx, Ccy) movable over the base panel (18); a fine positioning device (Cfx, Cfy) carried by and movable over the coarse positioning device; and a holder (14) for holding a working medium (16) substantially in contact with the base panel (18). The apparatus further includes first measuring means for measuring the location of a preselected point on the coarse positioning device (Ccx, Ccy) with respect to a preselected fiducial mark of the base panel (18); and second measuring means carried by the fine positioning device (Cfx, Cfy) for measuring the location of a point to be measured on the working medium (16) with respect to the preselected point on the coarse positioning device (Ccx, Ccy).</p> |
