Invention Grant

Gramophone record
Abstract:
A gramophone record includes a main body and a cladding layer. The main body is made of a polymeric material, and has a base surface and an extending surface which extends downward from the base surface. The extending surface defines a continuous spiral groove in the main body. The cladding layer is formed on the extending surface, and has a Hardness Rockwell C (HRC) of not less than 37.
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