Patents by Inventor Hal A. Rosen

Hal A. Rosen has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Two-sided optical disks having recording layers disposed close to outer surfaces and spaced axially apart a greater distance and devices for using the disks
    Patent number: 5392262
    Abstract: A magnetooptical disk has two axially space-apart translucent recording layers. Each translucent recording layer is axially closer to an outer surface of the disk than to the other recording layer. This geometry enables closely axially disposing a magnetic field biasing means to each of the recording layers from opposite axial sides of the disk, respectively. Laser beams are axially introduced into the disk to pass through one of the translucent recording layers in a defocussed state to reach a second recording layer in a focussed state. In this manner, recording in the second layer is effected by a modulated magnetic bias field using a constant intensity laser beam. Two sets of laser beams and magnetic biasing means are provided for recording on both data in both of the recording layers.
    Type: Grant
    Filed: December 31, 1992
    Date of Patent: February 21, 1995
    Assignee: International Business Machines Corporation
    Inventors: Blair I. Finkelstein, Andrew A. Gaudet, Terry W. McDaniel, Hal A. Rosen, Kurt A. Rubin, Timothy C. Strand