Optical glass

• US 10,259,738 B2
• Filed: 08/10/2016
• Issued: 04/16/2019
• 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:
  US15/751,202
• Publication Number:
  US 20180230038A1
• Time in Patent Office: 979 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 having a refractive index of 1.86-1.92 and an Abbe number of 36-42. The components of the optical glass comprise, 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%; Al₂O₃: 0-10%; GeO₂: 0-10%; Bi₂O₃: 0-10%. The optical glass does not contain PbO or F. A high refraction low dispersion optical glass having excellent light transmittance may be obtained by introducing suitable amounts of rare earth oxides having a high refraction low dispersion effect and optimizing the proportions of said components.

Claims

1. An optical glass comprising by weight percentage:

B₂O₃;

1-30%;

SiO₂;

0-20%, La₂O₃;

25-55%;

Gd₂O₃;

5-40%;

Y₂O₃;

greater than 0 and up to and including 25%;

Yb₂O₃;

0-10%;

Ta₂O₅;

0-10%;

Nb₂O₅;

1-30%;

TiO₂;

greater than 0 and up to and including 10%;

ZrO₂;

0.5-20%;

WO₃;

0-10%;

ZnO;

0-15%;

Al₂O₃;

0-10%;

GeO₂;

0-10%; and

Bi₂O₃;

0-10%;

PbO and F are excluded;

the glass has a refractive index of 1.86-1.92 and an Abbe number of 36-42,

wherein

SiO₂≤

B₂O₃;

Nb₂O₅ is greater than or equal to ZrO₂;

Nb₂O₅/(Nb₂O₅+TiO₂+ZrO₂) is 0.4-0.8.

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

Sb₂O₃;

0-1%;

SnO₂;

0-1%;

or CeO₂;

0-1%;

R₂O;

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

RO;

0-10%, wherein RO is at least one of BaO, SrO, MgO or CaO.

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

Y₂O₃/(La₂O₃+Gd₂O₃+Y₂O₃+Yb₂O₃) is below 0.2;

Y₂O₃/(La₂O₃+Gd₂O₃+Y₂O₃) is 0.01-0.15;

Nb₂O₅/(Nb₂O₅+TiO₂+ZrO₂) is 0.45-0.7 (Nb₂O₅+Ta₂O₅+ZrO₂)/(SiO₂+B₂O₃) is less than 1; and

(ZnO+Y₂O₃)/La₂O₃ is below 0.5.

4. The optical glass according to claim 1, wherein SiO₂/(SiO₂+B₂O₃) is 0.1-0.45;

Y₂O₃/(La₂O₃+Gd₂O₃+Y₂O₃) is 0.05-0.12;

Nb₂O₅/(Nb₂O₅+TiO₂+ZrO₂) is 0.48-0.6;

(Nb₂O₅+Ta₂O₅+ZrO₂)/(SiO₂+B₂O₃) is 0.1-0.9; and

(ZnO+Y₂O₃)/La₂O₃ is 0.05-0.3.

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

(Nb₂O₅+Ta₂O₅+ZrO₂)/(SiO₂+B₂O₃) is 0.5-0.8;

(ZnO+Y₂O₃)/La₂O₃ is 0.08-0.15.

6. The optical glass according to claim 1, wherein the glass has a refractive index from 1.87 to 1.91, and an Abbe number from 37 to 41.

7. 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.

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

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

10. The optical glass according to claim 1, wherein B₂O₃:

7-20%;

SiO₂;

3-12%;

La₂O₃;

35-50%;

Gd₂O₃;

10-30%;

Y₂O₃;

2-15%;

Ta₂O₅;

0-5%;

Nb₂O₅;

3-20%;

TiO₂;

0.5-3%;

ZrO₂;

3-10%.

11. 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%.