Patents Assigned to Poratechno Co., Ltd.
  • Patent number: 7045216
    Abstract: A polarizing plate with which, not only suppression in a drop in polarization efficiency, but also with which hue shift and light leakage do not substantially occur, under a high humidity/high temperature environment is provided. The polarizing plate of the present invention includes a polyvinyl-alcohol-based polarizing film, a protective film mainly composed of a cyclic-olefin-based resin and laminated on at least one side of the polarizing film, and an anchor coat agent film and an adhesive layer interposed between the polarizing film and the protective film. The amount of change in optical in-plane retardation of the protective film is 5 nm or less, after 24 hours in an atmosphere of 80° C., and the wetting tension of the laminated surface is 500 ?N/cm (23° C.) or more. The anchor coat agent is made of polyester polyol and polyisocyanate, and the adhesive layer is made of polyvinyl-alcohol-based adhesive.
    Type: Grant
    Filed: December 28, 2000
    Date of Patent: May 16, 2006
    Assignees: Gunze Co., Ltd., Poratechno Co., Ltd.
    Inventors: Yoshinori Ishii, Takeshi Yamamoto, Takao Uesugi, Koichi Watanabe
  • Patent number: 6985292
    Abstract: A polarizing plate with a drop in polarization efficiency, hue shift, and light leakage do not substantially occur under a high humidity/high temperature environment, and a liquid crystal display device utilizing the same are provided. The polarizing plate of the present invention includes a polyvinyl-alcohol-based polarizing film wherein after being subjected to an atmosphere of 80° C. and 90% RH for 24 hours, the retention of the polarization efficiency is 0.97 or more, the retention of the luminance is 3.0 or less, and an absolute value for the amount of change in value “a” is 0.6 or less and an absolute value for the amount of change in value “b” is 1.0 or less, according to the Hunter-Lab method. A liquid crystal display device of the present invention includes such a polarizing plate affixed thereto.
    Type: Grant
    Filed: December 28, 2000
    Date of Patent: January 10, 2006
    Assignees: Gunze Co., Ltd., Poratechno Co., Ltd.
    Inventors: Yoshinori Ishii, Takao Uesugi, Koichi Watanabe
  • Patent number: 6726995
    Abstract: A polarizing plate with which a drop in polarization efficiency, hue shift, and light leakage do not substantially arise, under a high humidity/high temperature environment is provided. The polarizing plate of the present invention comprises a polyvinyl-alcohol-based polarizing film, a protective film having thereon two anchor coat agent layers, mainly composed of a cyclic-olefin-based resin, laminated on at least one side of the polarizing film, with an adhesive. The amount of change in optical in-plane retardation of the protective film is 5 nm or less after 24 hours in an atmosphere of 80° C., and the wetting tension of the anchor coated surface of the protective film is 500 &mgr;N/cm (23° C.) or more. The anchor coat agent layers include a first layer made of polyisocyanate and polyester polyol and/or polyether polyol, and a second layer made of polyvinyl alcohol. The adhesive is made of polyvinyl alcohol.
    Type: Grant
    Filed: October 23, 2002
    Date of Patent: April 27, 2004
    Assignees: Gunze Co., LTD, Poratechno Co., Ltd.
    Inventors: Yoshinori Ishii, Takeshi Yamamoto, Takao Uesugi, Koichi Watanabe