Optical glass having a negative anomalous dispersion

• US 5,952,256 A
• Filed: 03/12/1998
• Issued: 09/14/1999
• Est. Priority Date: 03/25/1997
• Status: Expired due to Term

• Current Assignee: Kabushiki Kaisha Ohara
• Original Assignee: Kabushiki Kaisha Ohara
• Inventors: Onozawa, Masahiro, Morishita, Michiko
• Primary Examiner(s): MARCHESCHI, MICHAEL A
• Application Number:
  US09/041,385
• Time in Patent Office: 551 Days
• Field of Search: 501/63, 501/64, 501/65, 501/67, 501/70, 501/77, 501/78, 501/79, 501/900, 501/901, 501/903
• US Class Current: 501/63
• CPC Class Codes: C03C 3/064 containing boron
• CPC Class Codes: C03C 3/097 containing phosphorus, niobium or tantalum
• CPC Class Codes: C03C 4/00 Compositions for glass with special properties

Abstract

An optical glass has a large negative anomalous dispersion value and optical constants of refractive index (nd) within a range of 1.65-1.80 and Abbe number (νd) within a range of 28-42. The optical glass includes, as its essential ingredients, in weight percent, 20-50% SiO₂, 6-20% B₂ O₃ where SiO₂ /B₂ O₃ ≦6, 0.5-15% ZrO₂ and 31-50% Nb₂ O₅.

Claims

1. An optical glass having a negative anomalous dispersion consisting in weight percent of:

space="preserve" listing-type="tabular">______________________________________ SiO.sub.2 20-50% B.sub.2 O.sub.3 6-20%where SiO.sub.2 /B.sub.2 O.sub.3 ≦

6 in weight percent, ZrO.sub.2 0.5-15% Nb.sub.2 O.sub.5 31-50% Al.sub.2 O.sub.3 0-4% GeO.sub.2 0-5% Y.sub.2 O.sub.3 0-5% La.sub.2 O.sub.3 0-5% Gd.sub.2 O.sub.3 0-5% Yb.sub.2 O.sub.3 0-5% Ta.sub.2 O.sub.5 0-15% WO.sub.3 0-10% ZnO 0-14% MgO 0-7% CaO 0.5-4% SrO 0-14% BaO 0-14% Li.sub.2 O 0.5-10% Na.sub.2 O 0-15% K.sub.2 O 0-8.7% Sb.sub.2 O.sub.3 0-1%______________________________________

where SiO₂ /B₂ O₃ ≦

6 in weight percent,

space="preserve" listing-type="tabular">______________________________________ ZrO.sub.2 0.5-15% Nb.sub.2 O.sub.5 31-50% Al.sub.2 O.sub.3 0-4% GeO.sub.2 0-5% Y.sub.2 O.sub.3 0-5% La.sub.2 O.sub.3 0-5% Gd.sub.2 O.sub.3 0-5% Yb.sub.2 O.sub.3 0-5% Ta.sub.2 O.sub.5 0-15% WO.sub.3 0-10% ZnO 0-14% MgO 0-7% CaO 0.5-4% SrO 0-14% BaO 0-14% Li.sub.2 O 0.5-10% Na.sub.2 O 0-15% K.sub.2 O 0-8.7% Sb.sub.2 O.sub.3 0-1%______________________________________

and having a refractive index (nd) within a range from 1.65 to 1.78 and an Abbe number (ν

d) within a range form 28 to 38.1 and also having an anomalous dispersion (Δ

θ

g, F) of -0.001 or below.

2. An optical glass having a negative anomalous dispersion consisting in weight percent of:

space="preserve" listing-type="tabular">______________________________________ SiO.sub.2 20-40% B.sub.2 O.sub.3 6-20%______________________________________

where SiO₂ /B₂ O₃ ≦

6 in weight percent,

space="preserve" listing-type="tabular">______________________________________ZrO.sub.2 0.5-15%Nb.sub.2 O.sub.5 31-45%Al.sub.2 O.sub.3 0-4%GeO.sub.2 0-5%Y.sub.2 O.sub.3 + La.sub.2 O.sub.3 + Gd.sub.2 O.sub.3 + Yb.sub.2 O.sub.3 0-5%______________________________________

in which

space="preserve" listing-type="tabular">______________________________________Y.sub.2 O.sub.3 0-5%La.sub.2 O.sub.3 0-5%Gd.sub.2 O.sub.3 0-5%Yb.sub.2 O.sub.3 0-5%Ta.sub.2 O.sub.5 0-10%WO.sub.3 0-10%ZnO + MgO + CaO + SrO + BaO 0.5-20%______________________________________

in which

space="preserve" listing-type="tabular">______________________________________ZnO 0-14%MgO 0-7%CaO 0.5- 7!4%SrO 0-14%BaO 0-14%Li.sub.2 O + Na.sub.2 O + K.sub.2 O 0.5-20%______________________________________

in which

space="preserve" listing-type="tabular">______________________________________ Li.sub.2 O 0.5-10% Na.sub.2 O 0-15% K.sub.2 O 0- 10!8.7% Sb.sub.2 O.sub.3 0-1%______________________________________

and having a refractive index (nd) within a range from 1.65 to 1.78 and an Abbe number (ν

d) within a range from 28 to 38.1 and also having an anomalous dispersion Δ

θ

g, F of -0.001 or below.