Lead and arsenic free optical lanthanum borate glass

• US 7,638,450 B2
• Filed: 04/27/2006
• Issued: 12/29/2009
• Est. Priority Date: 04/29/2005
• Status: Expired due to Fees

• Current Assignee: Schott AG (Carl-Zeiss-Stiftung)
• Original Assignee: Schott AG (Carl-Zeiss-Stiftung)
• Inventors: Hansen, Stefanie, Woelfel, Ute, Ritter, Simone Monika
• Primary Examiner(s): Mayes; Melvin C
• Assistant Examiner(s): PATEL, SMITA S
• Application Number:
  US11/412,673
• Publication Number:
  US 20060247119A1
• Time in Patent Office: 1,342 Days
• Field of Search: 501/78, 501/79
• US Class Current: 501/79
• CPC Class Codes: C03C 3/068 containing rare earths

Abstract

The lead-free, fluorine-free and arsenic-free optical glass, which is useful in mapping, projection, telecommunication, optical communication engineering, and mobile drive and laser technology, has a refractive index of 1.75≦n_d≦1.83, an Abbe number of 34≦V_d≦44, and Tg≦560° C. The glass is free of WO₃ and TeO₂and has a composition in percent by weight based on oxide content of: SiO₂, 0.5-8; B₂O₃, 10-25; ZnO, 10-22; La₂O₃, 23-34; Ta₂O₅, >15-25; Nb₂O₅, 0.5-15; Al₂O₃, 0-2; and can include optional ingredients, e.g. alkali and/or alkaline-earth oxides. In addition, a sum of B₂O₃ and ZnO is 33 to 41% by weight and preferably a sum of La₂O₃+Ta₂O₅+Nb₂O_5+Y2O_3+ZrO2 is greater than 50% by weight.

Claims

1. A lead-free, fluorine-free and arsenic-free optical glass having a refractive index n_d of 1.75≦

n_d≦

1.83 and an Abbe number v_d of 34≦

v_d≦

44, said glass comprising, in percent by weight based on oxide content;

2. The optical glass as defined in claim 1, containing from 0.1 to 4 percent by weight of said Li₂O, from 1.65 to 10 percent by weight of said Σ

Alkali oxides, and from 0 to 1percent by weight of said at least one refining agent.

3. The optical glass as defined in claim 1, wherein a sum of La₂O₃+Ta₂O₅+Nb₂O₅+Y₂O₃+ZrO₂ is greater than 50 percent by weight.

6. The optical glass as defined in claim 1, containing up to one percent by weight of said at least one refining agent, and wherein said at least one refining agent is selected from the group consisting of Sb₂O₃, SnO, SO₄^2- and F.

7. The optical glass as defined in claim 1, which is free of gadolinium.

8. An optical element comprising an optical glass according to any one of claims 1 to 7, said optical element consisting of a lens, asphere, a prism, or a compact structural member for use in the field of mapping, projection, telecommunication, optical communication engineering, mobile drive, or laser technology.

9. An optical element comprising an optical glass according to any one of claims 1 to 7.

10. A method of making an optical element, comprising the step of precise pressing an optical glass according to any one of claims 1 to 7.

4. A lead-free, fluorine-free and arsenic-free optical glass having a refractive index n_dof 1.75≦

n_d1.83 and an Abbe number v_d of 34≦

v_d44, said glass comprising, in percent by weight based on oxide content;

5. A lead-free, fluorine-free and arsenic-free optical glass having a refractive index n_dof 1.75≦

n_d≦

1.83 and an Abbe number v_d of 34≦

v_d≦

44, said glass comprising, in percent by weight based on oxide content;