| 摘要 |
A mask structure and a mask positioning device, adapted to execute accurate and quick positioning of a mask having a generally ring-like shape, are disclosed. The mask structure includes a supporting frame of a generally ring-like shape, and at least one flat surface formed by a mirror surface is provided at a peripheral part of the supporting frame. Light is projected upon the flat surface and, on the basis of detection of reflected light therefrom, the mask can be positioned in regard to the rotational direction, inclination and orthogonal coordinate position. The mask positioning device is adapted to execute such positioning accurately and quickly. |
