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Measuring The Flight Height Of Magnetic Heads On Magnetic Disks

IP.com Disclosure Number: IPCOM000077794D
Original Publication Date: 1972-Sep-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Makosch, G: AUTHOR [+3]

Abstract

Beam 1 exiting from laser L is deflected by prism 2 through crystal 3 where it is split into an ordinary ray o and an extraordinary ray eo, which are polarized linearly and orthogonally to each other. Upon passing lambda /4 plate 4, rays o and eo are circularly polarized in opposite directions.

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Measuring The Flight Height Of Magnetic Heads On Magnetic Disks

Beam 1 exiting from laser L is deflected by prism 2 through crystal 3 where it is split into an ordinary ray o and an extraordinary ray eo, which are polarized linearly and orthogonally to each other. Upon passing lambda /4 plate 4, rays o and eo are circularly polarized in opposite directions.

Ordinary ray o is incident as reference beam R on the surface of magnetic disk 6, whereas extraordinary ray eo is incident as measuring beam M on the upper face of magnetic head 5 and is reflected, through lens 7, on mirror 8. From mirror 8 both rays are reflected back to the magnetic disk 6 and magnetized in such a manner that reference beam R is incident on magnetic disk 6 symmetrically to magnetic head 5, whereas measuring beam M, initially reflected from the upper face of magnetic head 5, is incident on the same point.

After a second reflection on 5, 6 the beams pass lambda /4 plate 4 a second time, and are again polarized linearly and orthogonally to each other and to the planes of polarization of the beams first exiting from birefringent crystal 3.

Upon passing crystal 3 the two beams are combined to a single beam, having two components polarized linearly and orthogonally to each other. This beam passes through lens 9 and is divided by beam splitter ]O into two beams of equal intensity, which are fed to two Wolloston prisms 12 and 13 to generate two pairs of interference line systems sensed by photodiode...