Patents by Inventor Vaddi Butchi Reddy

Vaddi Butchi Reddy 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).

  • Alkali iodide doped zinc sulfide electroluminescent phoshor
    Patent number: 6090311
    Abstract: An electroluminescent phosphor containing an alkali iodide dopant, such as lithium iodide or potassium iodide, and having CIE coordinates of x=0.173 to 0.187 and y=0.392 to <0.424. The phosphor without alkali iodide dopant has CIE coordinates of x.apprxeq.0.180 to 0.184 and y.apprxeq.0.424 to 0.426. The method of making the phosphor includes adding the alkali iodides during a second firing step.
    Type: Grant
    Filed: December 1, 1998
    Date of Patent: July 18, 2000
    Assignee: Osram Sylvania Inc.
    Inventors: Nathaniel E. Brese, Vaddi Butchi Reddy
  • Yttrium tantalate x-ray phosphors with reduced persistence
    Patent number: 5938974
    Abstract: A composition and method are provided for reducing the persistence of yttrium tantalate x-ray phosphors having the monoclinic M' structure. Persistence is reduced by incorporating a molybdenum or vanadium additive into the phosphor. The method for incorporating the molybdenum or vanadium additive consists of adding a molybdenum or vanadium containing compound to the mixture of raw materials formulated to make the phosphor and firing the mixture at a temperature and for a time sufficient to form the phosphor.
    Type: Grant
    Filed: September 10, 1998
    Date of Patent: August 17, 1999
    Assignee: Osram Sylvania Inc.
    Inventors: Gregory A. Marking, Vaddi Butchi Reddy
  • Yttrium tantalate x-ray phosphors with reduced persistence
    Patent number: 5900188
    Abstract: A composition and method are provided for reducing the persistence of yttrium tantalate x-ray phosphors having the monoclinic M' structure. Persistence is reduced by incorporating a tungsten additive into the phosphor. The phosphor preferably contains at least about 4 ppm W. The method for incorporating the tungsten additive consists of adding a tungsten containing compound to the mixture of raw materials formulated to make the phosphor and firing the mixture at a temperature and for a time sufficient to form the phosphor.
    Type: Grant
    Filed: September 23, 1997
    Date of Patent: May 4, 1999
    Assignee: Osram Sylvania Inc.
    Inventors: Gregory A. Marking, Vaddi Butchi Reddy, Kenneth T. Reilly
  • Lithium doped terbium activated gadolinium oxysulfide phosphor
    Patent number: 5783106
    Abstract: The brightness of small size terbium activated gadolinium oxysulfide (Gd.sub.2-x Tb.sub.x O.sub.2 S) phosphor is increased by the incorporation of a lithium dopant. The lithium dopant is added to the phosphor by mixing lithium phosphate with the raw materials formulated to make the phosphor.
    Type: Grant
    Filed: September 23, 1997
    Date of Patent: July 21, 1998
    Assignee: Osram Sylvania Inc.
    Inventors: Vaddi Butchi Reddy, Shellie K. Northrop
  • Yttrium tantalate x-ray phosphors with increased luminance and particle size
    Patent number: 5762827
    Abstract: A monoclinic M' yttrium tantalate x-ray phosphor containing a dopant selected from silicon or germanium to increase phosphor particle size and/or brightness. The phosphor is made by adding a silicon- or germanium-containing compound and a flux to the mixture of raw materials formulated to make the phosphor and then firing the doped mixture at a temperature and for a time sufficient to make the phosphor.
    Type: Grant
    Filed: August 1, 1997
    Date of Patent: June 9, 1998
    Assignee: Osram Sylvania Inc.
    Inventor: Vaddi Butchi Reddy
  • Reduction of lag in yttrium tantalate x-ray phosphors
    Patent number: 5716546
    Abstract: Phosphor lag was reduced to acceptable levels in high lag monoclinic M' yttrium tantalate x-ray phosphors through the addition of minor amounts europium to the phosphors. In particular, europium was added to yttrium tantalate phosphors containing terbium and to phosphors formulated with a stoichiometric excess of yttrium.
    Type: Grant
    Filed: October 23, 1996
    Date of Patent: February 10, 1998
    Assignee: Osram Sylvania Inc.
    Inventors: James R. Cox, Joseph A. Cooper, Cheryl M. Forster, Barry G. DeBoer, Vaddi Butchi Reddy, Ronald E. Karam
  • Improved blue-green emitting ZnS:Cu,Cl electroluminescent phosphor and method of making same
    Patent number: 5711898
    Abstract: An improved blue-green emitting ZnS:Cu,Cl phosphor is made by doping the phosphor with small amounts of gold and increasing the amount of low intensity milling between firing steps. The improved phosphor has better halflife and brightness characteristics while maintaining its desired emission color.
    Type: Grant
    Filed: April 24, 1996
    Date of Patent: January 27, 1998
    Assignee: Osram Sylvania Inc.
    Inventors: Vaddi Butchi Reddy, Kenneth T. Reilly
  • ZnS:Cu electroluminescent phosphor and method of making same
    Patent number: 5702643
    Abstract: A improved ZnS:Cu electroluminescent phosphor having a halflife of at least about 900 hours. The halflife improvement is made by doping the phosphor with minor amounts of gold and substantially increasing the amount of low intensity milling between firing steps. The improved phosphor has a dramatically longer halflife without sacrificing brightness or exhibiting large shifts in emission color.
    Type: Grant
    Filed: April 24, 1996
    Date of Patent: December 30, 1997
    Assignee: Osram Sylvania Inc.
    Inventors: Vaddi Butchi Reddy, Kenneth T. Reilly