Optical glass

• US 10,442,722 B2
• Filed: 08/10/2016
• Issued: 10/15/2019
• Est. Priority Date: 08/14/2015
• Status: Active Grant

• Current Assignee: CDGM Glass Company Limited (Konica Minolta Inc.)
• Original Assignee: CDGM Glass Company Limited (Konica Minolta Inc.)
• Inventors: Sun, Wei
• Primary Examiner(s): Bolden, Elizabeth A.
• Application Number:
  US15/751,295
• Publication Number:
  US 20180222786A1
• Time in Patent Office: 1,161 Days
• CPC Class Codes: C03C 3/068 containing rare earths
• CPC Class Codes: C03C 3/155 containing zirconium, titanium, tantalum or niobium

Abstract

A high refraction low dispersion optical glass, the components thereof including, by weight percentage: B₂O₃: 1-30%; SiO₂: 0-20%; La₂O₃: 25-55%; Gd₂O₃: 5-40%; Y₂O₃: 0-25%; Yb₂O₃: 0-10%; Ta₂O₅: 0-10%; Nb₂O₅: 1-30%; TiO₂: 0-10%; ZrO₂: 0.5-20%; WO₃: 0-10%; ZnO: 0-15%; R₂O: 0-10%; RO: 0-10%; Al₂O₃: 0-10%; GeO₂: 0-10%; Bi₂O₃: 0-10%. A high refraction low dispersion environmentally friendly optical glass having excellent light transmittance may be obtained by reducing the Ta₂O₅ content within the glass components and introducing suitable amounts of rare earth oxide components having a high refraction low dispersion effect.

Claims

1. An optical glass comprising by weight percentage:

B₂O₃;

1-30%;

SiO₂;

0-20%;

La₂O₃;

25-55%;

Gd₂O₃;

5-40%;

Y₂O₃;

0-25%;

Yb₂O₃;

0-10%;

Ta₂O₅;

0-10%;

Nb₂O₅;

1-30%;

TiO₂;

0-10%;

TiO₂/Nb₂O₅;

less than 0.25;

ZrO₂;

0.5-20%;

WO₃;

0-10%;

ZnO;

0-15%;

(ZnO+Y₂O₃)/La₂O₃;

less than 0.5;

R₂O;

0-10%, in which R₂O is at least one of Li₂O, Na₂O or K₂O;

RO;

0-10%, in which, RO is at least one of BaO, SrO, MgO or CaO;

Al₂O₃;

0-10%;

GeO₂;

0-10%;

Bi₂O₃;

0-10%;

the glass contains no PbO;

the glass has a refractive index of from 1.88 to 1.91, and an Abbe number of 35-45,

wherein

Nb₂O₅/(Nb₂O₅+TiO₂+ZrO₂) is 0.4-0.519;

(Nb₂O₅+Ta₂O₅+ZrO₂)/(SiO₂+B₂O₃) is 0.6-0.768; and

Nb₂O₅ is greater than ZrO₂.

2. The optical glass according to claim 1, optionally containing at least one of:

Sb₂O₃;

0-1%;

SnO₂;

0-1%;

or CeO₂;

0-1%.

3. The optical glass according to claim 2, wherein B₂O₃:

5-25%;

SiO₂;

0.1-15%;

La₂O₃;

30-52%;

Gd₂O₃;

5-35%;

Y₂O₃;

1-20%;

Ta₂O₅;

0-5%;

Nb₂O₅;

2-25%;

TiO₂;

0.1-5%;

ZrO₂;

1-15%;

WO₃;

0-5%;

ZnO;

0-10%;

R₂O;

0-5%;

RO;

0-5%;

Al₂O₃;

0-5%;

GeO₂;

0-5%;

Bi₂O₃;

0-5%;

Sb₂O₃;

0-0.5%;

SnO₂;

0-0.5%; and

CeO₂;

0-0.5%.

4. The optical glass according to claim 1, wherein SiO₂/(SiO₂+B₂O₃) is below 0.5;

Y₂O₃/(La₂O₃+Gd₂O₃+Y₂O₃) is below 0.2, and (ZnO+Y₂O₃)/La₂O₃ is in the range of 0.05-0.3.

5. The optical glass according to claim 1, wherein SiO₂/(SiO₂+B₂O₃) is 0.25-0.4;

Y₂O₃/(La₂O₃+Gd₂O₃+Y₂O₃) is 0.05-0.12;

Nb₂O₅/(Nb₂O₅+TiO₂+ZrO₂) is 0.48-0.519; and

(ZnO+Y₂O₃)/La₂O₃ is of 0.08-0.15.

6. The optical glass according to claim 1, wherein WO₃:

0-4%.

7. The optical glass according to claim 1, wherein the glass has an Abbe number from 37 to 41.

8. The optical glass according to claim 1, wherein the glass has a refractive index from 1.88 to 1.90, and an Abbe number from 38 to 40.

9. A glass preform made of the optical glass according to claim 1.

10. An optical element made of the optical glass according to claim 1.