A device for the processing of data in the form of magnetic recordings on a rotatable recording disc by means of one or more magnetic heads which are accommodated in a head plate which during operation is spaced at a relatively small distance from the disc. The surface of the plate facing the disc is provided with two groove patterns, the geometry of which being selected so that for one specific direction of rotation the summation of the pressures in the gap between plate and disc results in an air bearing having a zero bearing capacity and a high positive rigidity.
Apparatus for optically scanning an information plane of a disc-shaped optical record carrier having an underlying surface extending parallel to the information plane. A radiation source supplies a scanning beam, and an optical scanning unit has a lens system which focuses the scanning beam to a scanning spot on the information plane. The lens system has an optical axis, a first lens unit with a first lens having an entrance side (11) and an exit side (13), and a second lens unit with a second lens situated opposite the exit side of the first lens. The scanning unit also includes a drive motor for displacing the first lens along the optical axis and a rotation element for adjusting the position of the second lens with respect to the underlying surface of the record carrier. To inhibit spherical and/or comatic and astigmatism aberrations during scanning, the rotation element is rotatably driven and forms part of the second lens unit. It is journaled in a stationary element (17), and has a disc-shaped surface provided with a pattern of grooves therein. This results in increased air pressure in the gap between the underlying surface of the record carrier and the rotation element during scanning, thereby maintaining a correct gap spacing.
