WATERPROOF SOUND PASSING MEMBRANE, AND WATERPROOF SOUND PASSING MEMBER, ELECTRONIC APPARATUS, ELECTRONIC APPARATUS CASE AND WATERPROOF SOUND PASSING STRUCTURE INCLUDING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a waterproof sound passing membrane having a higher degree of freedom for controlling sound passing ability and waterproofness than the conventional ones, for example, capable of achieving both sound passing ability and waterproofness at a higher level.SOLUTION: A waterproof sound passing membrane comprises a polymer film having through holes extending from one main surface to the other main surface. In the waterproof sound passing membrane, each through hole is a straight hole in which the central axis of the through hole extends linearly, has a shape in which an area of a cross section that is perpendicular in a direction where the central axis extends increases from the one main surface of the polymer film toward the other main surface, the opening diameter (a) of the through hole at the one main surface is 12.0 μm or less, and the permeability from the other main surface to the one main surface is 2.0 cm/(cms) or more and 80 cm/(cms) or less as shown in a Frazier number measured in accordance with JIS standard L1096.SELECTED DRAWING: Figure 1