| 摘要 |
PROBLEM TO BE SOLVED: To easily manufacture a balloon which draws a free curvature at a low cost. SOLUTION: A strip-like protrusion becoming thick to a general surface of the balloon is formed on at least any one of an inner surface and an outer surface of a long-sized balloon having a substantially elliptical section. As another means, a low extendible thin sheet is arranged on any of the inner surface and the outer surface of the long-sized balloon having the substantially elliptical section. |
