Patents Assigned to Onda Techno
  • Patent number: 5902665
    Abstract: A glass substrate for a magnetic disk of the present invention is one in which a laser beam is irradiated on a magnetic recording surface side thereby forming a large number of protrusions thereon to form texture thereon, each of the protrusions having a convex shape, an optical absorption coefficient of a glass with respect to a wavelength of a laser beam at 266 nm being within a range of 20 to 2000 mm.sup.-1, the glass having a composition by weight of:silicon oxide (SiO.sub.2): 58 to 66%,aluminum oxide (Al.sub.2 O.sub.3): 13 to 19%,lithium oxide (Li.sub.2 O): 3 to 4.5%,sodium oxide (Na.sub.2 O): 6 to 13%,potassium oxide (K.sub.2 O); 0 to 5%,R.sub.2 O: 9 to 18% (provided R.sub.2 O=Li.sub.2 O+NaO+K.sub.2 O),magnesium oxide (MgO): 0 to 3.5%,calcium oxide (CaO): 1 to 7%;strontium oxide (SrO): 0 to 2%;barium oxide (BaO): 0 to 2%,RO: 2 to 10% (provided RO=MgO+CaO+SrO+BaO), andiron oxide (Fe.sub.2 O.sub.3): 0.05 to 2%,titanium oxide (TiO.sub.2): 0 to 2%,cerium oxide(CeO.sub.
    Type: Grant
    Filed: August 29, 1997
    Date of Patent: May 11, 1999
    Assignee: Onda Techno
    Inventor: Yasunao Kuroda