Magnetic head position control apparatus including drive means responsive to a summed signal from a capacitance detection electrode and a disk size detector means
US5168483A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 7, 1991 |
| Grant date | Dec 1, 1992 |
| Priority date | — |
| Expiry date | Oct 7, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B21/21
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A magnetic head position control apparatus for driving the magnetic head of a disc recording apparatus toward or away from the recording surface of a magneto-optical disc to effect position control of the magnetic head detects changes in the distance between the magnetic head and the magneto-optical disc by detecting changes in the capacitance between a capacitance detection electrode mounted on the magnetic head and a surface of the magnetic disc and generates a voltage to control the position of the magnetic head for maintaining it at a constant predetermined distance from the magneto-optical disc. Stray capacitance between the disc and the disc recording apparatus is based on the size of the disc, which is either detected directly or obtained from pre-recorded data on the disc, and is compensated by adding a bias voltage to the voltage generated using the capacitance detection electrode to provide further control of the position of the magnetic head.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.