Electronic devices such as mobile phones, laptop computers, electronic notebooks, digital cameras, and video game instruments usually have an audio function. Such an electronic device having an audio function includes a housing, in which is placed a sound emitting part such as a speaker or a buzzer or a sound receiving part such as a microphone. The housing is provided with an opening at a position corresponding to that of the sound emitting part or the sound receiving part. Sounds are transmitted through the opening. A sound-transmitting membrane is attached to the housing so as to cover the opening of the housing in order to prevent foreign matters such as water droplets from entering the housing. The sound-transmitting membrane allows sound to pass through but prevents foreign matters from passing through. Known examples of the sound-transmitting membrane include porous plastic membranes such as porous polytetrafluoroethylene membranes and porous ultrahigh molecular weight polyethylene membranes (see Patent Literature 1).
Patent Literature 2 describes a waterproof sound-transmitting member including a sound-transmitting membrane and a housing-side adhesive layer. The housing-side adhesive layer is a layer used to bond the waterproof sound-transmitting member to the housing and is laminated on the sound-transmitting membrane.
Patent Literature 3 describes a waterproof sound-transmitting member including a sound-transmitting membrane, a support layer, and a housing-side adhesive layer. In the waterproof sound-transmitting member described in Patent Literature 3, the entire peripheral portion of the support layer extends outwardly beyond the housing-side adhesive layer.