Patents by Inventor Tak Kojima

Tak Kojima 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).

  • Sheet glass flattening method, method of manufacturing an information recording glass substrate using flattened glass, method of manufacturing a magnetic disk using glass substrate, and magnetic recording medium
    Patent number: 5916656
    Abstract: A glass substrate manufacturing method advantageously applicable to magnetic recording disk glass substrates, LCD glass substrates, photomasks glass substrates, or optical memory glass substrates. The method includes the steps of forming a film of a solution on at least a principal surface of a sheet glass formed using a down-drawing method, the solution containing a water soluble inorganic material and a surface-active agent; sandwiching both sides of a single sheet glass on which the film is formed or of a laminated structure of two or more sheet glasses with a densified sheet with a high flatness to pressure the single glass or laminated structure; and heating and annealing the single sheet glass or laminated structure to flatten the same. The end side of the flatten glass substrate is treated with a treating solution containing a hydrofluosilicic acid.
    Type: Grant
    Filed: August 4, 1997
    Date of Patent: June 29, 1999
    Assignee: Hoya Corporation
    Inventors: Teruki Kitayama, Kazuhiko Sekiguchi, Teruhisa Fujita, Yoshio Murano, Sakuji Yoshihara, Tak Kojima