Lead and arsenic free optical lanthanum borate glass

• US 20060247119A1
• Filed: 04/27/2006
• Published: 11/02/2006
• Est. Priority Date: 04/29/2005
• Status: Active Grant

• Current Assignee: Schott AG (Carl-Zeiss-Stiftung)
• Original Assignee: Schott AG (Carl-Zeiss-Stiftung)
• Inventors: Hansen, Stefanie, Woelfel, Ute, Ritter, Simone Monika
• Granted Patent: US 7,638,450 B2
• Time in Patent Office: Days
• US Class Current: 501/78
• CPC Class Codes: C03C 3/068 containing rare earths

Abstract

The present invention describes lead and arsenic free and preferably gadolinium and further preferably also fluorine free optical glasses for the application fields mapping, projection, telecommunication, optical communication engineering, mobile drive and/or laser technology with a refractive index of 1.75≦n_d≦1.85, an Abbe number of 34≦v_d≦44 and have a low transformation temperature, namely lower than or equal to 560° C. and preferably lower than or equal to 550° C., as well as good producability and processability and crystallisation stability. The glasses according to the present invention within the following composition range (based on oxide in % by weight) contain the following components:

SiO₂0.5-8  B₂O₃10-25ZnO10-26La₂O₃18-34Ta₂O₅>15-25  Nb₂O₅0.5-15 WO₃ 0-10Al₂O₃0-2Li₂O0-5Na₂O0-6K₂O0-8Cs₂O0-9MgO0-5CaO0-5SrO0-5BaO0-5Y₂O₃ 0-10TiO₂0-6ZrO₂ 0-11HfO₂0-6Σ B₂O₃, ZnO30-45Preferably Σ La₂O₃, Ta₂O₃,>50Nb₂O₃, Y₂O₃, ZrO₂Σ Alkali oxides 0-15Σ Alkaline-earth oxides 0-15Σ Al₂O₃, Y₂O₃, WO₃, TiO₂, 0-15ZrO₂, Hf₂O₃, Alkaline-earth oxidesIn addition, they also may contain conventional refining agents.

Claims

1. A lead 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, characterized in that the glass comprises the following composition (based on oxide in % by weight);

3. The glass according to claim 1, wherein the sum of La₂O₃+Ta₂O₃+Nb₂O₃+Y₂O₃+ZrO₂ is higher than 50% by weight based on oxide.

4. The glass according to claim 1, which comprises the following composition (based on oxide in % by weight):

5. The glass according to claim 1, which comprises the following composition (based on oxide in % by weight):

6. The glass according to claim 1, containing, as a refining agent, at least one of the following components (in % by weight):

7. The glass according to claim 1, which is gadolinium-free and/or fluorine-free.

8. An optical element for use in the fields of mapping, telecommunication, optical communication engineering, projection, mobile drive and/or laser technology, said optical element comprising a glass according to claim 1.

9. A method of producing an optical element, said method comprising the step of precise pressing a glass according to claim 1.

2. A lead 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, characterized in that the glass comprises the following composition (based on oxide in % by weight);