| 摘要 |
<p>A double-sided exposure apparatus (1) with an optical registration system accurately aligns and prints a circuit pattern on both sides of a workpiece, such as a circuit board (40). The apparatus, with exposure chamber (2), has a computer system (8) in which setup parameters are entered to set the desired size of the board and accuracy of alignment. A control program of the computer (8) directs a machine vision system to inspect the workpiece and pattern, and computes precision movements of the workpiece which compensate for any sag or other variations in the glass or board that change between off-contact and soft contact. Before a board (40) is inserted into the exposure chamber (2), each artwork master is disposed on an artwork holder, specifically upper artwork holder (18) and lower artwork holder (20). The computer system (8) uses fiducials on the two artworks (17, 19) and target holes on each board (40) to align an artwork and the board (40) prior to exposure. At least one inspection of the fiducials, and realignment of the workpiece, is performed after the pattern is in contact with the workpiece, to thereby compensate for workpiece warpage, variations in sag or variations of the artwork holders (18, 20). Alignment uses video cameras (10, 12) mounted on precision slides (210, 212) to detect the centers of the fiducial and target using a 'best-fit' data processing method, which method includes compensation for any sag in the glass artwork holders (18, 20).</p> |
