Abstract )OE!vA
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. x!`~+f.6
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Inventors: Mori, Yoshio; (Yokohama-shi, JP) ; Onozawa, Masahiro; (Sagamihara-shi, JP) rk)h_zN
Correspondence Name and Address: HEDMAN & COSTIGAN P.C. q_b,3Tp
1185 AVENUE OF THE AMERICAS vwIP8z~<
NEW YORK ;Ob`B@!=b
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Assignee Name and Adress: Kabushiki Kaisha Ohara "eH.<&
1-15-30 Oyama Sagamihara-shi ,xOOR
Kanagawa-ken >mCS`D8
JP LEJn
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229-1186 8-geBlCE,
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Serial No.: 504112 ~fz9AhU8
Series Code: 10 =67tQx58
Filed: August 10, 2004 Jf3xK"in
PCT Filed: January 29, 2003 i"GCm`
PCT NO: PCT/JP03/00839 #7BX,jvn>
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U.S. Current Class: 359/883 Q$:>yveR*
U.S. Class at Publication: 359/883 Kn`-5{1B|
Intern'l Class: G02B 005/08 W_FN*Er
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Foreign Application Data mNdEn<W
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Date Code Application Number
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Feb 20, 2002 JP 2002-04342 %O02xr=
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Claims GSa U:A
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1. An optical glass comprising in mass %: HE.YfD)
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6 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% Al.sub.2O.sub.3 0-5% and being free of Ta.sub.2O.sub.5. XFJz\'{
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2. An optical glass as defined in claim 1 comprising, in mass %, 0.1-5% WO.sub.3. Og/@w&