| 摘要 |
<p>[Problems to be Solved] To provide a high-refractivity low-dispersion optical glass that enables the stable production of high-quality optical elements. [Means to Solve the Problems] An optical glass comprising, as essential components, 20 to 50% of B3+, 5 to 35% of La3+, 1 to 30% of Nb5+, 0.5 to 15% of Ta5+, and 11 to 40% of Zn2+, the total content of B3+ and Si4+ being 20 to 50%, the total content of La3+, Gd3+ and Y3+ being 5 to 35%, the cationic ratio of ((B3++Si4+)/(La3++Gd3++Y3+)) being from 1 to 5, the total content of Ti4+, Nb5+, Ta5+ and W6+ being 10 to 35%, the cationic ratio of ((Nb5++Ta5+)/(Ti4++Nb5++Ta5++W6+)) being from 0.7 to 1, the cationic ratio of ((B3++Si4+)/(Ti4++Nb5++Ta5++W6+)) being from 0.5 to 4, the cationic ratio of ((La3++Gd3++Y3+)/(Ti4++Nb5++Ta5++W6+)) being from 0.2 to 3, the cationic ratio of Zn2+/Zn2++Mg2++Ca2++Sr2++Ba2+) being from 0.8 to 1, the optical glass having a refractive index nd of 1.89 or more and an Abbe's number nud of 27 to 37.</p> |
