Disc streak pattern forming method and apparatus

A disc streak pattern forming apparatus for use in polishing an annular disc having a surface, a radially outer periphery and a radially inner periphery, and a center, the apparatus comprising:

• ring-shaped polishing means having a central axis, a central bore and a working surface in contact with said disc;
• a drive unit supporting thereon said ring-shaped polishing means in such a manner that at least a portion of the surface of said disc is disposed inside the central bore of said ring-shaped polishing means, said drive unit being operable to revolve said ring-shaped polishing means around the center of said disc and rotate said ring-shaped polishing means about its central axis while maintaining contact with the surface of said disc, thereby polishing the surface of said disc and forming streak patterns thereon;
• and
• said ring-shaped polishing means comprises at least one ring-shaped polishing pad, with said at least one ring-shaped polishing pad being disposed in such a manner that the radially outer periphery and the radially inner periphery of said at least one portion of the surface of said disc are both disposed inside the central bore of said at least one ring-shaped polishing pad.

A disc streak pattern forming method for use in polishing an annular disc having a storage surface, a radially outer periphery and a radially inner periphery, and a center, the method comprising the steps of:

• providing a ring-shaped polishing means having a central axis and defining a central bore therein, said ring-shaped polishing means comprising a plurality of ring-shaped polishing pads;
• placing the ring-shaped polishing means in contact with the surface of said disc, with at least one portion of the surface disposed inside the central bore of said ring-shaped polishing means;
• driving said ring-shaped polishing means to revolve about the center of said disc;
• driving said ring-shaped polishing means to rotate around its central axis;
• disposing said plurality of ring-shaped polishing pads about the center of said disc in such a manner that the radially outer periphery and the radially inner periphery of said at least one portion of the surface of said disc are both disposed inside the central bore of each of said ring-shaped polishing pads;
• and
• subjecting said respective ring-shaped polishing pads to said contacting revolving and self-rotating steps,
• whereby the surface of said disc is polished and provided with streak patterns by said ring-shaped polishing means.