| 摘要 |
At least a part of a shield plate (3) and a shutter (4) is constituted by a plurality of small pieces (3a, 3b, 4a, and 4b) linked to one another, and each of the plurality of small pieces (3a, 3b, 4a, and 4b) is provided with a linking section or linking sections by which each of the plurality of small pieces is linkable to one another and delinkable from one another. |
