OPTICAL GLASS, PREFORM FOR PRECISION PRESS MOLDING, OPTICAL ELEMENT, AND METHOD FOR MANUFACTURING OPTICAL ELEMENT

• US 20110257001A1
• Filed: 02/25/2011
• Published: 10/20/2011
• Est. Priority Date: 04/15/2010
• Status: Active Grant

• Current Assignee: Hoya Corporation
• Original Assignee: Hoya Corporation
• Inventors: Negishi, Tomoaki
• Granted Patent: US 8,609,560 B2
• Time in Patent Office: Days
• US Class Current: 501/42
• CPC Class Codes: C03C 3/068 containing rare earths
• CPC Class Codes: C03C 3/15 containing rare earths
• CPC Class Codes: C03C 3/155 containing zirconium, titanium, tantalum or niobium

Abstract

The present invention relates to an optical glass having a refractive index nd of 1.86 or higher and an Abbé number v(nu)d of 28 to 36; a preform for precision press molding and an optical element that are comprised of this glass; and a method for manufacturing the optical element.

Claims

1. An optical glass, comprising, denoted as cation percentages:

0 to 5% of Si⁴⁺,

25 to 45% of B³⁺,

0 to 20% of Li⁺,

0 to 5% of Na⁺,

0 to 5% of K⁺,

0 to 5% of Mg²⁺,

0 to 5% of Ca²⁺,

0 to 5% of Sr²⁺,

0 to 5% of Ba²⁺,

5 to 40% of Zn²⁺,

5 to 25% of La³⁺,

1 to 15% of Gd³⁺,

0 to 5% of Y³⁺,

0 to 5% of Yb³⁺,

0 to 3% of Zr⁴⁺,

1 to 15% of Ti⁴⁺,

0 to 5% of Nb⁵⁺,

0 to 5% of Ta⁵⁺,

1 to 30% of W⁶⁺,

0 to 5% of Te⁴⁺,

0 to 5% of Ge⁴⁺,

0 to 5% of Bi³⁺, and

0 to 5% of Al³⁺;

wherein the cation ratio of (B³⁺/(B³⁺+Si⁴⁺)) is 0.85 to 1.00;

the cation ratio of (B³⁺/(La³⁺+Gd³⁺+Y³⁺)) is 1.0 to 3.0;

the cation ratio of (B³⁺/(Ti⁴⁺+Nb⁵⁺+Ta⁵⁺+W⁶⁺)) is 0.5 to 4.0;

the cation ratio of (Zn²⁺/(Zn²⁺+Mg²⁺+Ca²⁺+Sr²⁺+Ba²⁺)) is 0.8 to 1.0;

the cation ratio of ((La³⁺+Gd³⁺+Y³⁺)/(Ti⁴⁺+Nb⁵⁺+Ta⁵⁺+W⁶⁺)) is 0.3 to 2.5;

the cation ratio of Ti⁴⁺/W⁶⁺ is 0.1 to 1.5;

the cation ratio of ((Ti⁴⁺+W⁶⁺)/(Ti⁴⁺+Nb⁵⁺+Ta⁵⁺+W⁶⁺)) is 0.8 to 1.0;

having a refractive index nd of 1.86 or higher, an Abbé

number vd of 28 to 36 and a liquidus temperature of 1000°

C. or lower.

2. The optical glass according to claim 1, wherein a glass transition temperature (Tg) is lower than 590°

C.

3. The optical glass according to claim 1, wherein a glass transition temperature is higher than 550°

C. to lower than 590°

C. and the glass comprises, denoted as cation percentages;

0 to 1.5% of Si⁴⁺,

29 to 40% of B³⁺,

0 to 3% of Li⁺,

0% of Na⁺,

0% of K⁺,

0% of Mg²⁺,

0% of Ca²⁺,

0% of Sr²⁺,

0% of Ba²⁺,

22 to 30% of Zn²⁺,

12 to 18% of La³⁺,

3 to 8% of Gd³⁺,

0% of Y³⁺,

0% of Yb³⁺,

0 to 0.8% of Zr⁴⁺,

5 to 9% of Ti⁴⁺,

0% of Nb⁵⁺,

0% of Ta⁵⁺,

6 to 18% of W⁶⁺,

0% of Te⁴⁺,

0% of Ge⁴⁺,

0% of Bi³⁺, and

0% of Al³⁺;

wherein the cation ratio of (B³⁺/(B³⁺+Si⁴⁺)) is 0.92 to 1.00;

the cation ratio of (B³⁺/(La³⁺+Gd³⁺+Y³⁺)) is 1.5 to 2.0;

the cation ratio of (B³⁺/(Ti⁴⁺+Nb⁵⁺+Ta⁵⁺+W⁶⁺)) is 1.40 to 2.62;

the cation ratio of (Zn²⁺/(Zn²⁺+Mg²⁺+Ca²⁺+Sr²⁺+Ba²⁺)) is 1.00;

the cation ratio of ((La³⁺+Gd³⁺+Y³⁺)/(Ti⁴⁺+Nb⁵⁺+Ta⁵⁺+W⁶⁺)) is 0.8 to 1.5;

the cation ratio of Ti⁴⁺/W⁶⁺ is 0.2 to 0.95;

the cation ratio of ((Ti⁴⁺+W⁶⁺)/(Ti⁴⁺+Nb⁵⁺+Ta⁵⁺+W⁶⁺)) is 1.00.

4. The optical glass according to claim 1, wherein a glass transition temperature is 490°

C. or higher to 550°

C. or lower and the glass comprises, denoted as cation percentages;

0 to 2% of Si⁴⁺,

28 to 40% of B³⁺,

1 to 15% of Li⁺,

0% of Na⁺,

0% of K⁺,

0% of Mg²⁺,

0% of Ca²⁺,

0% of Sr²⁺,

0% of Ba²⁺,

10 to 27% of Zn²⁺,

11 to 15% of La³⁺,

3 to 8% of Gd³⁺,

0% of Y³⁺,

0% of Yb³⁺,

0 to 0.8% of Zr⁴⁺,

3 to 8% of Ti⁴⁺,

0% of Nb⁵⁺,

0% of Ta⁵⁺,

7 to 22% of W⁶⁺,

0% of Te⁴⁺,

0% of Ge⁴⁺,

0% of Bi³⁺, and

0% of Al³⁺;

wherein the cation ratio of (B³⁺/(B³⁺+Si⁴⁺)) is 0.92 to 1.00;

the cation ratio of (B³⁺/(La³⁺+Gd³⁺+Y³⁺)) is 1.5 to 2.0;

the cation ratio of (B³⁺/(Ti⁴⁺+Nb⁵⁺+Ta⁵⁺+W⁶⁺)) is 1.00 to 3.00;

the cation ratio of (Zn²⁺/(Zn²⁺+Mg²⁺+Ca²⁺+Sr²⁺+Ba²⁺)) is 1.00;

the cation ratio of ((La³⁺+Gd³⁺+Y³⁺)/(Ti⁴⁺+Nb⁵⁺+Ta⁵⁺+W⁶⁺)) is 0.6 to 1.7;

the cation ratio of Ti⁴⁺/W⁶⁺ is 0.2 to 0.95;

the cation ratio of ((Ti⁴⁺+W⁶⁺)/(Ti⁴⁺+Nb⁵⁺+Ta⁵⁺+W⁶⁺)) is 1.00.

5. The optical glass according to claim 1, wherein the partial dispersion ratio Pg,F is 0.57 to 0.62.

6. The optical glass according to claim 3, wherein the partial dispersion ratio Pg,F is 0.57 to 0.62.

7. The optical glass according to claim 4, wherein the partial dispersion ratio Pg,F is 0.57 to 0.62.

8. A preform for precision press molding, comprised of the optical glass according to claim 1.

9. A preform for precision press molding, comprised of the optical glass according to claim 3.

10. A preform for precision press molding, comprised of the optical glass according to claim 4.

11. An optical element comprised of the optical glass according to claim 1.

12. An optical element comprised of the optical glass according to claim 3.

13. An optical element comprised of the optical glass according to claim 4.

14. A method for manufacturing an optical element, comprised of heating the preform for precision press molding according to claim 11 and employing a pressing mold to conduct precision press molding.