| 摘要 |
PURPOSE:To obtain high connection accuracy for not only parallel but perpendicular directions to a field boundary, by providing main and vernier graduations across and with a certain angle to the field boundary to measure two neighboring exposure boundaries, and by observing a difference between them. CONSTITUTION:Main 7 and vernier 9 graduations are provided across a boundary 2 between neighboring fields FL and FR to measure two neighboring exposure boundaries. In this constitution, the main graduations 7 consists of central long graduations C and graduations of equal intervals on both sides, and so does the vernier graduations 9. All the graduations are inclined 45 deg. or 135 deg. to the boundary 2, and aligned on the bases of central graduations C and CS for the main 7 and the vernier 9. This enables to tell the correct connection by only reading the graduations. |
