U.S. Philips Corporation

Koninklijke Philips Corporation N.v.

Mathijs De Jongh

Victor Zieren

Arnold Broese Van Groenou

Bernardus Hendrikus Wilhelmus Hendriks

Freddy Roozeboom

Coen Theodorus Hubertus Fransiscus Liedenbaum

Jacobus J Ruigrok

Willem Marie Julia Marcel Coene

Peter Lasinski

Leo-Franciscus M Van Oorschot

Franciscus W A Dirne

An optical scanning device for scanning an optical record carrier comprising an information layer. Crosstalk cancellation is provided using a phase modulating element () for generating a non-rotationally-symmetric phase profile in a subsidiary radiation beam. The phase profile varies with an azimuthal angle measured about the optical axis of the beam portion, the phase profile varying such that successively different phases are introduced in at least five locations which are each at successive azimuthal angles (&#x3c6;, &#x3c6;, &#x3c6;) and each at a given radial distance from the optical axis, wherein the phase profile is such that the phases introduced, when taken in modulo 2&#x3c0; form, successively cycle through 0 to 2&#x3c0; at least twice, whereby the subsidiary beam spot is provided with an intensity distribution on the information layer which overlaps that of the side-lobe of the main beam spot.

Optical scanning device

Magnetic head having a head face ( ) and comprising a head structure composed of thin layers and provided with a transducing element (E ), in which different materials occurring in different areas are present in the head face. The head face is provided with a first layer ( ) of a material which is more sensitive to corrosion than other materials in the head face, and the first layer is provided with a second layer ( ) of a wear-resistant material which is more insensitive to corrosion than the material of the first layer. The second layer constitutes a contact face ( ) for cooperation with a magnetic tape ( ).

Magnetic head having a wear-resistant layer, and method of manufacturing such a magnetic head

Magnetic head unit comprising a magnetic head secured in a housing and having a magnetic head structure provided with a head face and at least one transducing gap terminating in the head face. A wear- resistant layer (31 ) having at least one alignment mark (35, 36, 37) occupying a defined position with respect to the transducing gap is provided on the head face.

Magnetic head with wear resistant layer having alignment mark, and

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Eindhoven, Netherlands

Mathijs De Jongh