Patents by Inventor Hisashi Machida

Hisashi Machida 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).

  • Synthetic single crystal for alexandrite gem
    Patent number: 4240834
    Abstract: Disclosed is a synthetic single crystal for an alexandrite gem, which consists essentially of a synthetic chrysoberyl single crystal comprising aluminum oxide and beryllium oxide as the main components and chromium and vanadium as the coloring components, wherein vanadium is contained in an amount of about 0.00075 to about 2.95% by weight based on the crystal.This single crystal shows a green or bluish green color under natural light and the color is changed to red or reddish violet when the single crystal is exposed to tungsten light the single crystal of the present invention is comparable or superior to natural alexandrite produced in the Ural Mountain Region with respect to the hue and color change characteristics.
    Type: Grant
    Filed: September 14, 1979
    Date of Patent: December 23, 1980
    Assignee: Kyoto Ceramic Co., Ltd.
    Inventors: Hisashi Machida, Yoichiro Yoshihara