The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 11, 2003
Filed:
Mar. 26, 2001
Fumiaki Kataoka, Chiba, JP;
Kiyoshi Tamura, Chiba, JP;
Yoshitaka Sato, Chiba, JP;
Yuji Nomura, Chiba, JP;
Futaba Denshi Kogyo Kabushiki Kaisha, Chiba, JP;
Abstract
The present invention provides a phosphor of formula A SiO :B (A is Y or Gd, and B is Ce or Tb) which is characterized by a surface elemental composition represented by (A+B)/Si ranging from 1.5 to 2.5, wherein A is Y or Gd, and B is Ce or Tb; and method for preparing said phosphor. One embodiment of the method is as follows: a SiO powder is mixed with co-precipitate (Y, Ce) O (Ce/Y=0.01), in an amount ranging from 10 to 110 mol % based on the amount of (Y, Ce) O , and the mixture is charged into the inner crucible of a double-walled aluminum crucible. After graphite is charged between the inner and outer crucible, the mixture is calcined at 1450° C. for 2 hours to obtain an Y SiO :Ce phosphor. The luminous efficiency of a field emission display (FED) prepared employing the Y SiO :Ce phosphor was measured at an anode voltage of 600V, an electric power input of 30 Wp-p and a duty rate of 1/240. It is desirable that the relative amount of SiO based on the amount of (Y, Ce) O ranges from 40 to 70 mol %, preferably 50 to 60 mol %.