Glass, optical glass, glass raw material for press molding, and optical element

Patent metadata

Field	Value
Publication number	US-9359246-B2
Application number	US-201314410240-A
Country	US
Kind code	B2
Filing date	Jun 21, 2013
Priority date	Jun 22, 2012
Publication date	Jun 7, 2016
Grant date	Jun 7, 2016

Abstract

A glass including at least one type of oxide selected from TiO 2 , Nb 2 O 5 , WO 3 , and Bi 2 O 3 as a glass component therefor, having a total TiO 2 , Nb 2 O 5 , WO 3 , and Bi 2 O 3 content of at least 20 mol %, and having a βOH value indicated in formula (1) that fulfills the relationship indicated in formula (2).

β OH =−[ln( B/A )]/ t   (1);

β OH ≧0.4891×ln(1/ HR )+2.48  (2).

First claim

The invention claimed is:

1. An optical glass comprising at least one oxide selected from the group consisting of TiO 2 , Nb 2 O 5 , WO 3 and Bi 2 O 3 as a glass component, wherein
a total content of said TiO 2 , Nb 2 O 5 , WO 3 , and Bi 2 O 3 is 20 mol % or more, and
a value of βOH shown in below equation (1) satisfies a relation shown in below equation (2);
β OH =−[ln( B/A )]/ t   (1);

β OH ≧0.4891×ln(1 /HR )+2.48  (2);

in the equation (1), “t” is a thickness of said glass used for a measurement of an external transmittance, “A” is the external transmittance (%) at a wavelength of 2500 nm when a light enters into said glass in parallel to a thickness direction thereof, and “B” is the external transmittance (%) at the wavelength of 2900 nm when a light enters into said glass in parallel to the thickness direction thereof; in the equation (2), “HR” shows a total amount (mol %) of a content of each component of TiO 2 , Nb 2 O 5 , WO 3 and Bi 2 O 3 in said glass; in the equations (1) and (2), “ln” is natural logarithm.

2. The optical glass as set forth in claim 1 comprising P 2 O 5 as a glass component.

3. The optical glass as set forth in claim 2 , wherein a content of P 2 O 5 is larger than a content of B 2 O 3 in terms of mol % expression.

4. The optical glass as set forth in claim 1 , wherein a total content of said TiO 2 , Nb 2 O 5 , WO 3 and Bi 2 O 3 is 25 mol % or more.

5. The optical glass as set forth in claim 1 wherein substantially free of V.

6. A glass material for press-molding comprising the optical glass as set forth in claim 1 .

7. An optical element comprising the optical glass as set forth in claim 1 .

8. The optical glass as set forth in claim 1 , wherein a total content of said TiO 2 , Nb 2 O 5 , WO 3 and Bi 2 O 3 is 35 mol % or more.

9. The optical glass as set forth in claim 1 , wherein TiO 2 is 1 mol % or more.

10. The optical glass as set forth in claim 1 , wherein a content of Pt is 1.8 ppm or less.

11. The optical glass as set forth in claim 1 , wherein the glass transition temperature Tg is 541° C. or more.

12. The optical glass as set forth in claim 1 , wherein a content of Sb 2 O 3 is 0 ppm or more and less than 1000 ppm.

13. The optical glass as set forth in claim 1 , wherein a content of Sb 2 O 3 is 0 ppm or more and 500 ppm or less.

Assignees

• Mikami Shuhei
• Fujiwara Yasuhiro
• Hoya Corp

Inventors

• Mikami Shuhei
• Fujiwara Yasuhiro

Classifications

• C03B5/16 Primary

  Special features of the melting process; Auxiliary means specially adapted for glass-melting furnaces · CPC title

• C03C3/064 Primary

  containing boron · CPC title

• Y02P40/57

  Improving the yield, e-g- reduction of reject rates · CPC title

• C03B11/005

  Pressing under special atmospheres, e.g. inert, reactive, vacuum, clean · CPC title

• C03B5/193 Primary

  using gas, e.g. bubblers · CPC title