Patents by Inventor Mizuho Takeda

Mizuho Takeda 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).

  • Phosphor which emits light by the excitation of X-ray, and a X-ray intensifying screen using the phosphor
    Patent number: 5250366
    Abstract: The phosphor and the X-rays intensifing screen according to the present inventin emit light by the excitation of X-ray, and they are used for medical and industrial radiography. In addition to the conventional contents of rare earth tantalate and/or rare earth niobate, the phosphor according to the present invention contains a determined quantity of divalent metal. This divalent metal content can make the improvement of the afterglow characteristic and the light emission characteristic of the phosphor. The phosphor according to the present invention is represented by the general formula (I) MyLn.sub.1 -x-(2/3)yDO.sub.4 : xR.sup.3+ (I).
    Type: Grant
    Filed: May 8, 1992
    Date of Patent: October 5, 1993
    Assignee: Nichia Kagaku Kogyo K.K.
    Inventors: Shigeharu Nakajima, Genichi Shinomiya, Mizuho Takeda, Satoru Chikutei
  • X-ray phosphors and X-ray intensifying screen using the phosphor
    Patent number: 5120619
    Abstract: This invention relates to rare earth tantalate and/or niobate phosphors which emit light under X-ray excitation, and an X-ray intensifing screen which utilizes these phosphors. The phosphor is represented by the general formula (I);.sup.Ln 1-x-(2/3)y-(1/3)z.sup.M" y.sup.M' z.sup.DO 4:xR.sup.3+(I)In this formula, M" is at least one kind of divalent metal selected from the group consisting of Be, Mg, Ca, Sr, Zn and Cd, M' is at least one kind of alkali metal selected from the group consisting of Li, Na, Ba and K, Ln is at least one kind of element selected from the group consisting of Y, Gd, La and Lu, D consists of Ta and/or Nb, and R is at least one selected from the group conssiting of Tm, Pr, Sm, Eu, Tb, Dy and Yb, y is a value in the range 1.times.10.sup.-5 .ltoreq.y.ltoreq.1, z is a value in range 1.times.10.sup.-4 .ltoreq.z.ltoreq.0.1, and x is a numerical value in the range 0.ltoreq..times..ltoreq.0.05.
    Type: Grant
    Filed: November 7, 1990
    Date of Patent: June 9, 1992
    Assignee: Nichia Kagaku Kogyo K.K.
    Inventors: Shigeharu Nakajima, Genichi Shinomiya, Mizuho Takeda, Satoru Chikutei
  • Phosphor which emits light by the excitation of X-ray
    Patent number: 4959174
    Abstract: The phosphor and the X-ray intensifying screen according to the present invention emit light by the excitation of X-rays and they are used for medical and industrial radiography. In addition to the conventional contents of rare earth tantalate and/or rare earth niobate, the phosphor according to the present invention contains a determined quantity of divalent metal. This divalent metal content can make the improvement of the afterglow characteristic and the light emission characteristic of the phosphor.The phosphor according to the present invention is represented by the general formula (I)MyLn.sub.1 -X-.sub.(2/3) yDO.sub.4 : xR.sup.3+ (I).
    Type: Grant
    Filed: March 16, 1989
    Date of Patent: September 25, 1990
    Assignee: Nichia Kagaku Kogyo K.K.
    Inventors: Shigeharu Nakajima, Genichi Shinomiya, Mizuho Takeda, Satoru Chikutei