Optical glass and use thereof

Patent metadata

Field	Value
Publication number	US-9394194-B2
Application number	US-201314387400-A
Country	US
Kind code	B2
Filing date	Mar 15, 2013
Priority date	Mar 26, 2012
Publication date	Jul 19, 2016
Grant date	Jul 19, 2016

Abstract

An optical glass is oxide glass wherein Si 4+ +B 3+ ranges from 10-60 cation %, La 3+ +Gd 3+ +Y 3+ +Yb 3+ ranges from 25-70 cation %, Ti 4+ +Nb 5+ +W 6+ +Bi 3+ ranges from 10-20 cation %, Li + content ranges from 0-5.0 cation %, Ge content is lower than 5.0 mass % as quantity of GeO 2 based on oxides, no Pb included, a cation ratio, Si 4+ /B 3+ , is equal or lower than 0.70, a cation ratio, (La 3+ +Gd 3+ +Y 3+ +Yb 3+ )/(Ti 4+ +Nb 5+ +W 6+ +Bi 3+ ), ranges from 1.90-7.00, a cation ratio, Y 3+ /(La 3+ +Gd 3+ +Y 3+ +Yb 3+ ), is equal or lower than 0.180, and Nb 5+ is an essential component, with Ti 4+ /Nb 5+ being equal or lower than 4.00, with nd of higher than 1.920 and equal or lower than 2.000, vd ranging from 28.0-34.0, and yield point higher than 645° C., and a deviation ΔPg,F from normal line of partial dispersion ratio Pg,F being equal or lower than 0.0005.

First claim

The invention claimed is:

1. Optical glass, which is oxide glass wherein:
a total content of Si 4+ and B 3+ ranges from 10 to 60 cation %;
a total content of La 3+ , Gd 3+ , Y 3+ , and Yb 3+ ranges from 25 to 70 cation %;
a total content of Ti 4+ , Nb 5+ , W 6 and Bi 3+ ranges from 10 to 20 cation %;
a content of Li + ranges from 0 to 5.0 cation %;
a content of Ge is lower than 5.0 mass % as a quantity of GeO 2 in a glass composition based on oxides;
no Pb is comprised;
a cation ratio of a content of Si 4+ to a content of B 3+ , Si 4 / B 3+ , is equal to or lower than 0.70;
a cation ratio of the total content of La 3+ , Gd 3+ , Y 3+ , and Yb 3+ to the total content of Ti 4+ , Nb 5+ , W 6+ , and Bi 3+ , (La 3+ +Gd 3+ +Y 3+ +Yb 3+ )/(Ti 4+ +Nb 5+ +W 6+ +Bi 3+ ), ranges from 1.90 to 7.00;
a cation ratio of a content of Y 3+ to the total content La 3+ , Gd 3+ , Y 3+ , and Yb 3+ , Y 3+ /(La 3+ +Gd 3+ +Y 3+ +Yb 3+ ), is equal to or lower than 0.180; and
Nb 5+ is comprised as an essential component, with a cation ratio of a content of Ti 4+ to a content of Nb 5+ , Ti 4+ /Nb 5+ , being equal to or lower than 4.00;
which has a refractive index nd within a range of higher than 1.920 and equal to or lower than 2.000, an Abbé number vd ranging from 31.5 to 34.0, and a yield point of higher than 645° C.; and
wherein a deviation ΔPg,F from a normal line of a partial dispersion ratio Pg,F obtained from the following equation is equal to or lower than 0.0005:
Δ Pg,F=Pg,F +(0.0018× vd )−0.6483

wherein, in the equation, Pg,F denotes a partial dispersion ratio given by (ng−nF)/(nF−nC) using various refractive indexes ng, nF, and nC at spectral lines g, F, and c; and vd denotes the Abbé number.

2. The optical glass according to claim 1 , wherein a content of Yb is lower than 2 mass % as a quantity of Yb 2 O 3 in the glass composition based on oxides.

3. The optical glass according to claim 1 , wherein a cation ratio of the total content of La 3+ , Gd 3+ , Y 3+ , and Yb 3+ to a total content of Si 4+ and B 3+ , (La 3+ +Gd 3+ +Y 3+ +Yb 3+ )/(Si 4+ +B 3+ ), is equal to or higher than 0.83, or a cation ratio of the total content of Ti 4+ , Nb 5+ , W 6+ , and Bi 3+ to the total content of Si 4+ and B 3+ , (Ti 4+ +Nb 5+ +W 6+ +Bi 3+ )/(Si 4+ +Bi 3+ ), is equal to or higher than 0.31.

4. The optical glass according to claim 1 , wherein a total content of Ti 4+ , Nb 5+ , W 6+ , Bi 3+ , and Ta 5+ ranges from 13 to 30 cation %.

5. The optical glass according to claim 1 , wherein a content of Si 4+ ranges from 1.0 to 30 cation %, a content of B 3+ ranges from 5 to 55 cation %, and a content of La 3+ ranges from 10 to 50 cation %.

6. The optical glass according to claim 1 , wherein a content of Zr 4+ ranges from 1 to 15 cation %.

7. The optical glass according to claim 1 , wherein a content of Zn 2+ ranges from 0 to 15 cation %.

8. The optical glass according to claim 1 , which has a glass transition temperature of higher than 630° C.

9. The optical glass according to claim 1 , wherein a total content of Gd 3+ , Y 3+ , and Yb 3+ ranges from 0.5 to 35 cation %.

10. A press-molding glass gob, which is comprised of the optical glass according to claim 1 .

11. An optical element blank, which is comprised of the optical glass according to claim 1 .

12. An optical element, which is comprised of the optical glass according to claim 1 .

13. The optical glass according to claim 1 , wherein a cation ratio of the total content of La 3+ , Gd 3+ , y 3+ , and Yb 3+ to a total content of Si 4+ and B 3+ , (La 3+ +Gd 3+ +y 3+ +Yb 3+ )/(Si 4+ +B 3+ ), is equal to or higher than 0.83.

14. The optical glass according to claim 1 , wherein the Abbé number vd ranges from 32.0 to 34.0.

15. The optical glass according to claim 1 , wherein a content of Zn 2+ is equal to or greater than 0.1 cation %.

16. The optical glass according to claim 1 , wherein the optical glass contains no As.

Assignees

• Negishi Tomoaki
• Hoya Corp

Inventors

• Negishi Tomoaki

Classifications

• C03C3/068 Primary

  containing rare earths · CPC title

• C03C3/095

  containing rare earths · CPC title

• C03C3/155

  containing zirconium, titanium, tantalum or niobium · CPC title