초록 ▼

The invention relates to an improved apparatus for the manufacture of magnetic discs carrying very thin magnetic layers, by applying a fluid dispersion of magnetic materials in a binder mixture to rigid base discs by the spin-coating process. Above the side of the base disc which is to be provided w

The invention relates to an improved apparatus for the manufacture of magnetic discs carrying very thin magnetic layers, by applying a fluid dispersion of magnetic materials in a binder mixture to rigid base discs by the spin-coating process. Above the side of the base disc which is to be provided with the magnetic layer, there are arranged means which produce an aerodynamic boundary layer above the discs during rotation of the latter. This avoids the formation of surface irregularities and of coating streaks during production of the layer by spin-coating.

대표청구항 ▼

An apparatus for spin coating, in the production of thin magnetic layers for magnetic discs, a rigid base disc with a pourable dispersion of magnetic materials in a binder mixture, said apparatus comprising: variable-speed drive means for rotating said base disc, means for applying said dispersion t

An apparatus for spin coating, in the production of thin magnetic layers for magnetic discs, a rigid base disc with a pourable dispersion of magnetic materials in a binder mixture, said apparatus comprising: variable-speed drive means for rotating said base disc, means for applying said dispersion to said base disc while said drive means are rotating said disc at a relatively slow speed, a rigid, generally disc-shaped member, and means for attaching said member to said base disc for rotation therewith and in closely spaced parallel-planar relation thereto at least while said drive means rotate said disc at a relatively high speed during the spin-coating operation, so as to define between the flat surface of said base disc, which carries said dispersion, and the opposing flat surface of said member, a generally cylindrical air space open along its entire circumference, through which open circumference excess dispersion is spun off, and cause the air column extending in said space between said two flat surfaces to rotate, in the manner of an aerodynamic boundary layer, in a substantially stationary relationship to the surface of said disc, whereby the formation of surface irregularities during the production of said magnetic layer is substantially avoided.