| 摘要 |
PURPOSE:To easily position a fine pinhole by using a mask pattern which has the pinhole and mutually orthogonal straight line patterns formed on the same plane. CONSTITUTION:A control circuit 15 moves the mask pattern 10 in an (x) direction by a stage 14 firstly to shift the mask pattern 10 from the projecting position of a transmitted laser beam 16. The control circuit 15 stores a middle point 17, i.e. (x) coordinate when a light output is about a half as much as a maximum value and then the mask pattern 10 is returned to the position where the transmitted laser light 16 is cut off. Similar movement is carried out in a (y) direction as well and the (y) coordinate (yo) for realizing a middle point is stored. Lastly, the control circuit 5 moves the mask pattern 10 to the stored coordinates (xo, yo) and then moves the mask pattern 10 by distance (-a) in the (x) direction and by distance (-b) in the (y) direction. At this time, the pinhole pattern 11 is projected with the transmitted laser light 16.
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