Patents by Inventor Yasuhiro Higashi

Yasuhiro Higashi 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).

  • Optical recording medium and recording method using the same
    Patent number: 6225022
    Abstract: An optical recording medium has a substrate and a recording layer formed thereon, the recording layer containing at least one compound represented by formula (I): wherein M, R1 to R4 and X1 to X4 are as specified in the specification; and in addition, information can be recorded in the above-mentioned optical recording medium by applying a laser beam in a wavelength range of 630 to 720 nm thereto.
    Type: Grant
    Filed: July 22, 1998
    Date of Patent: May 1, 2001
    Assignee: Ricoh Company, Ltd.
    Inventors: Tatsuya Tomura, Tsutomu Sato, Noboru Sasa, Yasunobu Ueno, Yasuhiro Higashi
  • Optical recording medium
    Patent number: 6197477
    Abstract: An optical recording material including a substrate and a recording layer which is formed overlying the substrate, wherein the recording layer includes an azo chelate compound including an azo compound and at least one of a metal and a metal salt, and wherein the azo compound has the following formula (1):
    Type: Grant
    Filed: August 18, 1999
    Date of Patent: March 6, 2001
    Assignee: Ricoh Company, LTD
    Inventors: Tsutomu Satoh, Shohji Maruyama, Yasunobu Ueno, Tatsuya Tomura, Noboru Sasa, Yasuhiro Higashi
  • Optical recording medium and recording and/or reproduction method using the same
    Patent number: 6057020
    Abstract: An optical recording medium has a substrate and a recording layer which is formed on the substrate and contains an azo metal chelate compound including an azo moiety of formula (I) and a bivalent or trivalent metal; ##STR1## wherein X is OH group, CooH group or CONH.sub.2 group; Y is a residual group forming a heterocyclic ring in combination with nitrogen atoms bonded thereto; and Z is a residual group forming an aromatic ring in combination with carbon atoms bonded thereto. In addition, there is provided a method of recording information and reproducing the information using the above-mentioned optical recording medium.
    Type: Grant
    Filed: April 27, 1998
    Date of Patent: May 2, 2000
    Assignee: Ricoh Company, Ltd.
    Inventors: Yasunobu Ueno, Tsutomu Sato, Tatsuya Tomura, Noboru Sasa, Yasuhiro Higashi
  • Optical information recording medium
    Patent number: 5998093
    Abstract: An optical information recording medium includes a substrate, and a recording layer formed on the substrate, the recording layer containing at least one compound selected from the group consisting of a compound represented by formula (I): ##STR1## and a compound represented by formula (II): ##STR2##
    Type: Grant
    Filed: January 29, 1997
    Date of Patent: December 7, 1999
    Assignee: Ricoh Company, Ltd.
    Inventors: Tatsuya Tomura, Tsutomu Satoh, Noboru Sasa, Yasunobu Ueno, Yasuhiro Higashi