The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 30, 2003
Filed:
Mar. 27, 2000
Andrew M. Hawryluk, Los Altos Hills, CA (US);
Robert D. Hempstead, Los Gatos, CA (US);
David A. Markle, Saratoga, CA (US);
Ultratech Stepper, Inc., San Jose, CA (US);
Abstract
A method of, and apparatus for, defining disk tracks in magnetic recording media. The track-writing apparatus ( ) is capable of forming tracks ( ) with a track width (TW) and track spaces ( ) with a space width (SW) on a magnetic media disk ( ) having an upper surface ( S), wherein the disk comprises a magnetic medium with a thermal diffusion length (X). The apparatus comprises, in order along an optical axis (A ), a laser light source ( ) capable of providing a pulsed laser light beam (B ), a light pipe ( ), and illumination shaping optical system ( ) that provides substantially uniform illumination over an exposure region (ER), and a phase plate ( ) having a phase grating ( ) with a grating period (p), arranged proximate and substantially parallel to the upper surface of the disk so as to form an periodic irradiance distribution ( ) at the surface of the disk when the phase plate is illuminated with the exposure region. The irradiance distribution is capable of heating one or more regions of the disk to beyond the Curie temperature of the magnetic media. A method of defining the disk tracks using Spatial Period Division (SPD) with the track writing apparatus described above by forming closed annular demagnetized spaces in a periodic magnetized pattern ( ) formed in the disk is also disclosed.