Abrading – Abrading process – Glass or stone abrading
Patent
1998-08-19
2000-09-12
Scherbel, David A.
Abrading
Abrading process
Glass or stone abrading
451 63, 451264, 451274, 451283, B04B 100
Patent
active
061169870
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to methods and apparatuses for polishing hard discs including, but not limited to, resinous optical discs, lenses, and metallic discs such as silicon wafers.
BACKGROUND OF THE INVENTION
In recent years, resinous optical discs are being used for various purposes such as for music discs, CD-ROM for computers, and cinema discs. A reason for the rapid diffusion is that the memories of such discs are rarely damaged by optical reading.
However, the surface layers covering the memories are made of transparent resin. This resinous surface is easily scratched. Reading errors (eg. sound "jumping" or movement of pictures) are caused by the scratches. In order to eliminate the scratches, it is necessary to polish the surface layer.
In one typical polishing method, a polishing pad, which is used as a polishing material, contacts the surface of a disc which is to be polished (hereinafter referred to as "the surface for polishing"). The diameter of such a polishing pad is the same as the width of surface for polishing. The disc and the polishing pad are simultaneously rotated. An abrasive is poured between the polishing pad and the disc and then the disc is polished.
The above mentioned polishing methods have the following problems.
(1) Irregularities may be caused by the polishing pad which is rotating under a constant condition, since the speed of the inside of a disc is different from the speed of the outside (since the outside is faster than the inside, the inside of a disc is more difficult to polish than the outside).
(2) Static electricity is generated by the friction between the disc and a polishing pad, and then polishing-dust sticks to the surface of the disc.
(3) The disc is overheated by the frictional heat, and the disc is, then, deformed.
SUMMARY OF THE INVENTION
Accordingly, it is the object of the present invention to provide methods and apparatuses for polishing hard discs uniformly while minimizing frictional electricity between the discs and polishing materials as well as preventing, and which prevent from frictionally heated deformation of the discs occurring.
To accomplish the fore-mentioned objects of the present invention: an apparatus for polishing hard discs comprising; a rotatable turntable place a disc thereon, a polishing material which polishes the surface of the disc by contacting the disc, said polishing material rotates horizontally, a spindle of the polishing material slightly inclines toward the center of the turntable from the vertical axis of the disc. The turntable is rotated in the opposite direction to the rotating direction of the disc by the friction between the disc and the polishing material. This enables the surface of the disc to be polished uniformly.
A conductive mat is mounted on the turntable, and the turntable is essentially grounded. Static electricity, which is generated by the friction between the disc and the polishing material, is thereby eliminated, and polishing dust is prevented from sticking to the surface of the disc.
A temperature sensor which detects the temperature of the disc is provided. Temperature information is processed so that the polishing material shall be released from the disc when the disc overheats. Deformation of the disc is whereby prevented.
A porous backing pad is deposited between the polishing material and spindle, whereby frictional heat of the polishing material is discharged.
A polishing material having a diameter which is larger than the width of surface to be polished of a disc is employed. In particular, the surface to be polished is covered by a polishing material which has radius that is the same as, or larger than, the width of the surface to be polished (refer FIG. 6). The disc is rotated in the opposite direction to the rotating direction of the polishing material by the rotation of the polishing material, and then the disc is polished. Thereby the disc is stably rotated and is polished uniformly.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partially cutaway view in fragme
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Nguyen George
Scherbel David A.
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