Optical glass and optical element
An optical glass is provided which does not contain components negatively affecting the environment as environmental loads, and is less colored while having a refractive index maintained moderately high. The optical glass has a composition including, in % by mass, 30% or more and 47% or less of SiO 2 , 0% or more and 10% or less of B 2 O 3 , 3% or more and 12% or less of Na 2 O, 0% or more and 5% or less of Li 2 O, 0% or more and 3.8% or less of CaO, 28% or more and 43% or less of BaO, 3% or more and 16% or less of ZnO, 0% or more and 8% or less of ZrO 2 , 0% or more and 15% or less of La 2 O 3 , where Sb 2 O 3 is excluded from the composition, wherein the optical glass does not contain any of PbO, As 2 O 3 , and K 2 O.
1. An optical glass having a composition including only, in % by mass:
30% or more and 47% or less of SiO 2 ;
0% or more and 10% or less of B 2 O 3 ;
3% or more and 12% or less of Na 2 O;
0% or more and 5% or less of Li 2 O;
0% or more and 3.8% or less of CaO;
28% or more and 43% or less of BaO;
3% or more and 16% or less of ZnO;
0.5% or more and 8% or less of ZrO 2 ; and
0% or more and 15% or less of La 2 O 3 ,
wherein the composition optionally includes Sb 2 O 3 ,
where the proportions of SiO 2 , B 2 O 3 , Na 2 O, Li 2 O, CaO, BaO, ZnO, ZrO 2 , and La 2 O 3 , are relative to the sum of the contents of the components except for Sb 2 O 3 , if included, constituting the composition, and
the optical glass has a proportion of a content of BaO in a sum of contents of CaO and BaO of 91.5% by mass or more.
2. The optical glass of claim 1 having a refractive index (nd) of 1.58 or higher and 1.66 or lower.
3. The optical glass of claim 2 having a coloration degree (λ 80) of 34 or lower.
4. An optical element comprising the optical glass of claim 2 .
5. The optical glass of claim 2 containing Sb 2 O 3 , where a content of Sb 2 O 3 is 1% by mass or less with respect to 100% by mass of the composition.
6. The optical glass of claim 1 having a coloration degree (λ 80) of 34 or lower.
7. An optical element comprising the optical glass of claim 6 .
8. The optical glass of claim 6 containing Sb 2 O 3 , where a content of Sb 2 O 3 is 1% by mass or less with respect to 100% by mass of the composition.
9. An optical element comprising the optical glass of claim 1 .
10. The optical glass of claim 1 containing Sb 2 O 3 , wherein a content of Sb 2 O 3 is 1% by mass or less with respect to 100% by mass of the composition.
11. The optical glass of claim 1 , wherein a proportion of Na 2 O is 5% or more.
12. The optical glass of claim 1 , wherein a proportion of Na 2 O is 5.59% or more.
13. The optical glass of claim 1 , wherein a total proportion of Na 2 O and Li 2 O is 5% or more.
14. The optical glass of claim 1 , wherein a total proportion of Na 2 O and Li 2 O is 5.59% or more.
15. The optical glass of claim 1 , wherein a proportion of La 2 O 3 is 7% or more.
16. The optical glass of claim 1 , wherein a proportion of BaO is 30% or more and 39% or less.
17. The optical glass of claim 1 , wherein a proportion of BaO is 39% or less and a proportion of SiO 2 is 42% or less.