Differential-permeability field-concentrating magnetic read/write head
US4494125A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 7, 1983 |
| Grant date | Jan 15, 1985 |
| Priority date | — |
| Expiry date | Mar 7, 2003 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G19/00
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A magnetic-image read/write head including inner and outer, substantially co-planar, symmetrically arranged pole portions. In one embodiment, the head is disclosed with the inner pole portion presenting a substantially full-circular facial expanse, and with the outer pole portion presenting an annular facial expanse surrounding that of the inner pole portion. In another embodiment, each of the two pole portions presents a substantially annular facial expanse with the inner pole being hollow. In both embodiments, the inner pole portion has a magnetic permeability which is significantly lower than that of the outer pole portion. An image unit written on a magnetic-image-storage medium by the head takes the form, generally, of a dot characterized by an appreciably larger magnetic field intensity adjacent its perimeter than inside the perimeter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.