US 7,320,949 B2
Optical glass
Susumu Uehara, Sagamihara (Japan)
Assigned to Kabushiki Kaisha Ohara, Kanagawa-ken (Japan)
Filed on Jun. 02, 2004, as Appl. No. 10/859,022.
Application 10/859022 is a continuation in part of application No. 10/404788, filed on Apr. 01, 2003, granted, now 6,828,265.
Claims priority of application No. 2002-099810 (JP), filed on Apr. 02, 2002; and application No. 2002-282336 (JP), filed on Sep. 27, 2002.
Prior Publication US 2004/0220040 A1, Nov. 04, 2004
This patent is subject to a terminal disclaimer.
Int. Cl. C03C 3/062 (2006.01); C03C 3/068 (2006.01); C03C 4/00 (2006.01)
U.S. Cl. 501—73  [501/78; 501/901] 4 Claims
 
1. An optical glass having a refractive index of (nd) of 1.88 or over and an Abbe number (νd) within a range from 22 to 28, comprising, in mass %,
   
  SiO2 15-20% 
  B2O3 0-5% 
  La2O3 0-5% 
  TiO2 5-15%
  ZrO2 0-10%
  Nb2O5 more than 30%
    and
    less than 50%
  WO3 0-5% 
  CaO 0-10%
  BaO 0-10%
  Li2O 3-12%
  Na2O 0-10%
  K2O 0-10%
  Bi2O3 0-15%
  Ta2O5 0-7% 
   
and having a glass transition point (Tg) within a range from 500° C. to 580° C.