When L4 represents a curved circumferential length of the top surface of protrusion 209 as illustrated in FIG. 18B, wave shape 210 is set such that uncurved circumferential length L3 of the top surface of protrusion 209 is greater than L4 (L3≥L4) as illustrated in FIG. 18A. When the films are curved as illustrated FIG. 18B, an extending force is applied to laminate film 201 on the upper side; however, wave 210 on the top surface of protrusion 209 extends, which absorbs the amount of extension (in FIGS. 17A and 17B, L2-L1). As a result, it is possible to prevent the surfaces of laminate films 201 and 202 from wrinkling or cracking.

However, in the configuration of the related art, in a case where an external force is applied in a direction parallel to a ridge of the wave as illustrated in FIG. 19A, and the laminate films are curved in a state as illustrated in FIG. 19B, it is not possible for the wave to extend. As a result, a problem arises in that wrinkling or cracking appears. This is because, as illustrated in FIG. 20, the laminate film, on which the wave shape is formed, extends in a direction perpendicular to the ridge of the wave, but does not extend in a direction parallel thereto. In addition, since the laminate film does not extend in any direction except for the direction perpendicular to the ridge of the wave, that is, in a diagonal direction, wrinkling or cracking is also likely to appear when an external force is applied in the corresponding direction and the film is curved.