Optical glass, optical element using optical glass, and optical device

Patent metadata

Field	Value
Publication number	US-9988300-B2
Application number	US-201715428691-A
Country	US
Kind code	B2
Filing date	Feb 9, 2017
Priority date	Sep 5, 2014
Publication date	Jun 5, 2018
Grant date	Jun 5, 2018

Abstract

An optical glass which is suitable for mold press molding. The optical glass contains, in weight %, 10-25% of B 2 O 3 , 30-60% of P 2 O 5 , 0-5% of Al 2 O 3 , 0.1-10% of Li 2 O, 0-15% of SrO, 10-50% of BaO, 0-12% of ZnO, 0-5% of Y 2 O 3 and 0-5% of Gd 2 O 3 , while not containing La 2 O 3 .

First claim

The invention claimed is:

1. An optical glass containing the following each component, in weight %:
10-25% of B 2 O 3 ;
30-60% of P 2 O 5 ;
0-5% of Al 2 O 3 ;
0.1-10% of Li 2 O;
0-15% of SrO;
10-50% of BaO;
0-12% of ZnO;
0-5% of Y 2 O 3 ;
0-5% of Gd 2 O 3 ;
0-4% of MgO; and
0-4% of CaO,
while not containing La 2 O 3 ,
wherein a total amount of Y 2 O 3 and Gd 2 O 3 in the optical glass is at least 1.35 weight % and is equal to or less than 5 weight %, and
a total amount of MgO and CaO in the optical glass is equal to or less than 4 weight %.

2. The optical glass according to claim 1 , containing the following each component, in weight %:
0-8% of Na 2 O; and
0-8% of K 2 O.

3. The optical glass according to claim 1 , having a refractive index (nd) in a range of 1.56-1.61, and an Abbe's number (νd) in a range of 63-70.

4. The optical glass according to claim 1 , having a glass-transition temperature (Tg) equal to or less than 530° C.

5. The optical glass according to claim 1 , having a liquid phase temperature (Tl) equal to or less than 1000° C.

6. The optical glass according to claim 1 , wherein devitrification does not occur, when a temperature of the optical glass is cooled from equal to or more than the liquid phase temperature to equal to or less than the glass-transition temperature, at a temperature reduction rate of 200° C./h.

7. An optical element using the optical glass according to claim 1 .

8. An optical device equipped with the optical element according to claim 7 .

Assignees

• Nikon Corp

Inventors

• Yoshimoto Kohei
• Yamamoto Hiroshi

Classifications

• G02B1/00

  Optical elements characterised by the material of which they are made; Optical coatings for optical elements · CPC title

• C03C3/19 Primary

  containing boron · CPC title

• C03C3/064

  containing boron · CPC title

• C03C3/068

  containing rare earths · CPC title