Patent ID: 8855357

Claim:
A speaker diaphragm made of paper manufactured from a material comprising: a first fiber material beaten to have a given freeness; and a second fiber material made by carbonizing bamboo fiber fibrillated into a microfibril state, wherein the second fiber material is beaten to have a given freeness not greater than 15 cc, the second fiber material is contained in the speaker diaphragm by a content ranging from 5 wt % to 50 wt %, the second fiber material has an average fiber diameter of smaller than 5 μm and not smaller than 1 μm, a ratio of an average fiber length to an average fiber diameter is equal to or greater than 10 and equal to or less than 2000, and carbonization temperature ranges from 500° C. to 1000° C. and carbonization time ranges from 24 hours to 120 hours.