| 摘要 |
PURPOSE:To detect the rotational angle of a chip precisely by detecting the centers of leads extending from one side of a molding and those of leads extending from the other side, and by finding the angles of virtual lines connecting the pairs of the centers against reference lines. CONSTITUTION:After the visual field of a camerais set at a position where other nozzles 3b, 3d are not in, a visual field A1 is set, and the X and Y coordinates AH1-AHn of the centers of the tips of leads L extending from the left-hand side side (a) are detected. Then a visual field A2 is set, and the X and Y coordinates BH1-BHn of the centers of the tips of leads extending from the right-hand side side (b) are detected. Furthermore virtual lines l1-ln which connected the X and Y coordinates, AH1 with BH1, AH2 with BH2,... AHn with BHn are found. And angles theta1-thetan of these virtual lines l1-ln with respect to reference lines N are found respectively, and their average value thetam is calculated. This makes it possible to find the rotational angle thetam of the chip P precisely. |
