Polymer film, waterproof sound-permeable membrane, waterproof sound-permeable member, electronic device, electronic device case, waterproof sound transmission structure, waterproof gas-permeable membrane, waterproof gas-permeable member, waterproof ventilation structure, suction sheet, method for holding workpiece by suction on suction unit, method for producing ceramic capacitor, optical film, optical member, and composition

Abstract

The polymer film of the present invention has through holes extending from one principal surface of the polymer film to the other principal surface of the polymer film. The through holes are straight holes having a central axis extending straight, and have a shape in which the area of a cross-section perpendicular to the direction of the central axis increases from the one principal surface of the polymer film toward the other principal surface. This polymer film has passages in its thickness direction, has an unconventional structure, and can be used in various applications, such as in a waterproof sound-permeable membrane, in a waterproof gas-permeable membrane, and in a suction sheet. The ratio a/b of the opening diameter a of the through holes at the one principal surface to the opening diameter b of the through holes at the other principal surface is 80% or is less than 80%.

Dependencies are inferred from the claim text.