Patents by Inventor Yohta Sakon

Yohta Sakon 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).

  • Patent number: 5597925
    Abstract: An electroluminescent device is composed of a negative electrode, a positive electrode, and an organic compound layer which is interposed between the negative electrode and the positive electrode and includes at least one oxadiazole compound with a plurality of aryl oxadiazole structures. Novel oxadiazole compounds for use in the electroluminescent device and a method of producing the oxadiazole compounds are disclosed.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: January 28, 1997
    Assignee: Ricoh Company, Ltd.
    Inventors: Masafumi Ohta, Yohta Sakon, Toshihiko Takahashi, Chihaya Adachi, Kazukiyo Nagai
  • Patent number: 5420288
    Abstract: An electroluminescent device is composed of a negative electrode, a positive electrode, and an organic compound layer which is interposed between the negative electrode and the positive electrode and includes at least one oxadiazole compound with a plurality of aryl oxadiazole structures. Novel oxadiazole compounds for use in the electroluminescent device and a method of producing the oxadiazole compounds are disclosed.
    Type: Grant
    Filed: April 14, 1993
    Date of Patent: May 30, 1995
    Assignee: Ricoh Company, Ltd.
    Inventors: Masafumi Ohta, Yohta Sakon, Toshihiko Takahashi, Chihaya Adachi, Kazukiyo Nagai
  • Patent number: 5153073
    Abstract: Disclosed herein is an electroluminescent device comprising an anode and a cathode and one or plurality of organic compound layer sandwiched therebetween, at least one of the organic compound layers being composed of an organic compound represented by the general formula (I): ##STR1## (wherein A.sup.1 and A.sup.2 each represents a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group which may be identical or different with each other, Ar represents a substituted or unsubstituted pyrenyl group and n represents 1 or 2).
    Type: Grant
    Filed: June 28, 1991
    Date of Patent: October 6, 1992
    Assignee: Ricoh Company, Ltd.
    Inventors: Teruyuki Ohnuma, Tomoyuki Shimada, Masafumi Ohta, Fumio Kawamura, Yohta Sakon, Toshihiko Takahashi
  • Patent number: 5118986
    Abstract: An electroluminescent device having:an anode and a cathode; andat least two organic compound layers sandwiched between said two electrodes,at least one of said organic compound layers being a hole transporting layer containing a compound represented by the following general formula (I) ##STR1## wherein R.sup.1 represents hydrogen atom, a lower alkyl group, a lower alkoxy groups, a halogen or a nitro group, A represents ##STR2## (wherein R.sup.2 represents a lower alkyl group, a substituted or non-substituted aryl group or an aralkyl group, and R.sup.3 represents a lower alkyl group.
    Type: Grant
    Filed: June 21, 1990
    Date of Patent: June 2, 1992
    Assignee: Ricoh Company, Ltd.
    Inventors: Teruyuki Ohnuma, Fumio Kawamura, Masafumi Ohta, Yohta Sakon, Toshihiko Takahashi, Mitsuru Hashimoto
  • Patent number: 5093210
    Abstract: Disclosed herein is an electroluminescent device having a luminescent layer comprising a luminescent material, which is capable of directly converting the energy of electric field applied thereto into a light energy and capable of providing a large surface-area luminescence.
    Type: Grant
    Filed: June 28, 1990
    Date of Patent: March 3, 1992
    Assignee: Ricoh Company, Ltd.
    Inventors: Masafumi Ohta, Teruyuki Ohnuma, Fumio Kawamura, Yohta Sakon, Toshihiko Takahashi
  • Patent number: 5077142
    Abstract: Disclosed herein an electroluminescent device for converting an energy of an electric field applied directly to a light energy and capable of producing surface luminescent for a large area different from conventional incandescent lamps, fluorescent lamps or light emitting diodes.
    Type: Grant
    Filed: April 19, 1990
    Date of Patent: December 31, 1991
    Assignee: Ricoh Company, Ltd.
    Inventors: Yohta Sakon, Teruyuki Ohnuma, Mitsuru Hashimoto, Shogo Saito, Tetsuo Tsutsui, Chihaya Adachi