Waterproof sound-transmitting sheet for facilitating vision inspection

A waterproof sound-transmitting sheet for facilitating a vision inspection comprising:

• an upper waterproof layer composed of a porous membrane;
• a lower waterproof layer composed of the porous membrane and disposed under the upper waterproof layer;
• and
• an acoustic layer composed of the porous membrane and interposed between the upper waterproof layer and the lower waterproof layer,
• wherein the porous membrane of at least one of the upper waterproof layer and the lower waterproof layer is a porous colored membrane having a color other than white and black, and
• wherein the upper waterproof layer and the lower waterproof layer include a fiber structure in a straight shape, whereas the porous membrane of the acoustic layer includes a fiber structure in a spring shape with more curves than those of the upper waterproof layer and the lower waterproof layer.