Patents by Inventor Kazutomo Miyata

Kazutomo Miyata 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).

  • Over-write capable magnetooptical recording medium having reading layer
    Patent number: 5343449
    Abstract: A medium comprises a reading layer, a memory layer and a writing layer. The reading layer, the memory layer and the writing layer are exchange-coupled to each other to form a three-layered structure. The medium satisfies the following condition at room temperature and during reproduction:i) 2M.sub.SR H.sub.CR t.sub.R <.sigma..sub.WR1 ;ii) 2M.sub.SR H.sub.CR t.sub.R +2M.sub.S1 H.sub.C1 t.sub.1 >.sigma..sub.W12 ;iii) Hb<(.sigma..sub.WR1 /2M.sub.SR t.sub.R)+H.sub.CR,where t.sub.R is a film thickness of the reading layer, t.sub.1 is a film thickness of the memory layer, M.sub.SR is saturation magnetization of the reading layer, M.sub.S1 is saturation magnetization of the memory layer, H.sub.CR is a coercivity of the reading layer, H.sub.C1 is a coercivity of the memory layer, .sigma..sub.WR1 is an exchange coupling force between the reading layer and the memory layer, .sigma..sub.W12 is an exchange coupling force between the memory layer and the writing layer, and Hb is a recording magnetic field.
    Type: Grant
    Filed: September 17, 1993
    Date of Patent: August 30, 1994
    Assignee: Nikon Corporation
    Inventor: Kazutomo Miyata