Abstract 9_3M}|V$^e  
An optical glass comprising in mass %: 1 P.sub.2O.sub.5 25%-less than 45% B.sub.2O.sub.3 6-20% BaO 24%-less than 40% ZnO 3-14% MgO 0-15% CaO 0-15% SrO 0-15% Li.sub.2O 0-5% Na.sub.2O 0-5% K.sub.2O 0-5% WO.sub.3 0-5% and Al.sub.2O.sub.3 0-5%. The optical glass should preferably contain 0.1-5% WO.sub.3, 3.6-15% MgO, 0.1-5% Li.sub.2O+Na.sub.2O+K.sub.2O, 0--less than 0.5% and Sb.sub.2O.sub.3+As.sub.2O.sub.3 with the mass ratio of ZnO/BaO being 0.12--less than 0.50. The optical glass should preferably have refractive index (nd) within a range from 1.54 to 1.65 and Abbe number (.nu.d) within a range exceeding 57 up to 69 and liquid phase temperature within a range from 870.degree. C. to 930.degree. C. There is provided an optical glass having high resistance to devitrification and medium refractive index and low dispersion characteristics which is free of ingredients such as Ta.sub.2O.sub.5 having a high cost of raw material and therefore can be manufactured at a relatively low cost of raw materials. :N}KScS|Wa  
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Inventors: Mori, Yoshio; (Yokohama-shi, JP) ; Onozawa, Masahiro; (Sagamihara-shi, JP)   +kL(lBv'  
Correspondence Name and Address:      HEDMAN & COSTIGAN P.C. 
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   1185 AVENUE OF THE AMERICAS o=QF>\\  
   NEW YORK N sL"p2w~  
   NY ,m,vo_Ub  
   10036 :F=nb+HZ  
   US }HorR2(`N  
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Assignee Name and Adress: Kabushiki Kaisha Ohara ud D[hPJd  
1-15-30 Oyama Sagamihara-shi us%RQ8=k  
Kanagawa-ken 9lCKz !E
 
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229-1186 [Gy'0P(EQ  
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Serial No.:  504112 c&
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Series Code:  10   {W<-f?  
Filed:  August 10, 2004 Ai18]QD-  
PCT Filed:  January 29, 2003 6~WE#z_  
PCT NO:  PCT/JP03/00839 wf%Ep#^6}  
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U.S. Current Class: 359/883   %)Dd{|c  
U.S. Class at Publication: 359/883   d|RmU/
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Intern'l Class:  G02B 005/08 ZS]f+}0/}  
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