Granted Patent B2

US 12,559,413 · App. 18/247,645 · Granted Feb 24, 2026

Inventor: Tatsuya Tezuka (Saitama, JP)

Assignee: Sumita Optical Glass, Inc.

C03C3/19C03C3/17C03C3/21

Abstract

Claims (35)

1 . An optical glass comprising a composition consisting only of, by mol %:

0% or more and 15% or less B 2 O 3 ;

25% or more and 40% or less P 2 O 5 , the total content of B 2 O 3 and P 2 O 5 being 35% or more and 45% or less;

0% or more and 10% or less Al 2 O 3 ;

5% or more and 15% or less Li 2 O;

0% or more and 15% or less Na 2 O;

0% or more and 5% or less K 2 O;

0% or more and 35% or less MgO;

0% or more and 35% or less CaO, the total content of MgO and CaO being 20% or more;

0% or more and 5% or less ZnO;

0% or more and 3% or less ZrO 2 ;

0% or more and 3% or less Y 2 O 3 ;

0% or more and 3% or less La 2 O 3 ; and

0% or more and 3% or less Gd 2 O 3 ,

wherein the composition does not contain SrO and BaO, and

the optical glass has an Abbe number (νd) of 62 or more and 70 or less.

2 . The optical glass according to claim 1 , wherein the optical glass has a refractive index (nd) of 1.50 or more and 1.60 or less.

3 . An optical element comprising, as a material, the optical glass according to claim 1 .

4 . The optical glass according to claim 2 , wherein the optical glass has a specific gravity of 2.90 or less.

5 . The optical glass according to claim 2 , wherein an absolute value of a temperature coefficient of a relative refractive index of the optical glass for a wavelength of 587.6 nm with respect to 0° C. and 20° C. is 2.0× 10 −6 ° C. −1 or less.

6 . The optical glass according to claim 2 , wherein a class of DW of chemical durability measured by a surface method based on JOGIS 07-2019 is either Class 1 or 2.

7 . The optical glass according to claim 2 , wherein the optical glass has a glass-transition temperature Tg of 500° C. or less and a yield temperature At of 540° C. or less.

8 . A preform for precision press molding, comprising, as a material, the optical glass according to claim 2 .

9 . An optical element comprising, as a material, the optical glass according to claim 2 .

10 . The optical glass according to claim 1 , wherein the optical glass has a specific gravity of 2.90 or less.

11 . The optical glass according to claim 10 , wherein an absolute value of a temperature coefficient of a relative refractive index of the optical glass for a wavelength of 587.6 nm with respect to 0° C. and 20° C. is 2.0× 10 −6 ° C. −1 or less.

12 . The optical glass according to claim 10 , wherein a class of DW of chemical durability measured by a surface method based on JOGIS 07-2019 is either Class 1 or 2.

13 . The optical glass according to claim 10 , wherein the optical glass has a glass-transition temperature Tg of 500° C. or less and a yield temperature At of 540° C. or less.

14 . A preform for precision press molding, comprising, as a material, the optical glass according to claim 10 .

15 . An optical element comprising, as a material, the optical glass according to claim 10 .

16 . The optical glass according to claim 1 , wherein an absolute value of a temperature coefficient of a relative refractive index of the optical glass for a wavelength of 587.6 nm with respect to 0° C. and 20° C. is 2.0× 10 −6 ° C. −1 or less.

17 . The optical glass according to claim 16 , wherein a class of DW of chemical durability measured by a surface method based on JOGIS 07-2019 is either Class 1 or 2.

18 . The optical glass according to claim 1 , wherein a class of DW of chemical durability measured by a surface method based on JOGIS 07-2019 is either Class 1 or 2.

19 . The optical glass according to claim 1 , wherein the optical glass has a glass-transition temperature Tg of 500° C. or less and a yield temperature At of 540° C. or less.

20 . A preform for precision press molding, comprising, as a material, the optical glass according to claim 1 .

Assignments (1)

Priority Claims (1)

Continuity (1)

References Cited (19)