# US 10,370,289 B2 · Optical glass, preform, and optical element

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- Number: US 10,370,289 B2
- Document ID: US10370289B2
- Status: Granted
- Kind: B2
- Application number: 15/347,185
- Filed: 2016-11-09
- Published: 2017-05-11
- Granted: 2019-08-06
- Earliest claimed: 2015-11-11
- Assignees: Kabushiki Kaisha Ohara
- Applicants: Ohara Inc.
- Inventors: Ken Kikkawa; Atsushi Nagaoka
- Web page: https://patentgrep.com/patent/US10370289B2

## CPC

- C03C 3/097: containing phosphorus, niobium or tantalum
- C03C 3/064: containing boron
- C03C 3/068: containing rare earths
- G02B 27/0062: {by controlling the dispersion of a lens material, e.g. adapting the relative partial dispersion}
- C03C: CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

An optical glass having a small partial dispersion ratio (θg,F), while having a refractive index (nd) and Abbe number (νd) within desired ranges, is obtained. The optical glass, in mass %, comprises 10.0 to 70.0% of an SiO2 component, 1.0 to 50.0% of an Nb2O5 component, and 1.0 to 30.0% of an Na2O component, and has a refractive index (nd) of 1.62 to 1.75, an Abbe number (νd) of 30 to 42, and a partial dispersion ratio (θg,F) of no greater than 0.594.

## Claims

### Claim 1

An optical glass comprising, in mass %,
10.0 to 70.0% of an SiO2 component,
more than 15.0% to 31% of an Nb2O5 component, and
1.0 to less than 20.0% of an Na2O component,
a B2O3 component is no less than 7.99% and no more than 25.0%,
a ZrO2 component is more than 1.0% and less than 15.0%,
a BaO component is less than 15.0%,
a Bi2O3 component is no more than 10.0%,
a ZnO component is no more than 30.0%,
a Li2O component is less than 5.0%,
a mass ratio (Li2O+Na2O)/(ZrO2) of no less than 1.30,
and having
a refractive index (nd) of 1.62 to 1.75,
an Abbe number (νd) of 30 to 42, and
a partial dispersion ratio (θg,F) of no greater than 0.594.

### Claim 2 (depends on 1)

An optical glass according to claim 1, wherein a mass ratio (SiO2)/(SiO2+B2O3) is no less than 0.50.

### Claim 3 (depends on 1)

An optical glass according to claim 1, wherein a mass ratio (SiO2)/(SiO2+B2O3) is no greater than 0.88.

### Claim 4 (depends on 1)

An optical glass according to claim 1, wherein, in mass %,
an K2O component is 0 to 20.0%,
a TiO2 component is 0 to 20.0%,
an MgO component is 0 to 10.0%,
a CaO component is 0 to 10.0%,
an SrO component is 0 to 10.0%,
a Ta2O3 component is 0 to 10.0%,
an La2O3 component is 0 to 10.0%,
a Gd2O3 component is 0 to 10.0%,
a Y2O3 component is 0 to 20.0%,
a Yb2O3 component is 0 to 10.0%,
a P2O5 component is 0 to 10.0%,
a GeO2 component is 0 to 10.0%,
an Al2O3 component is 0 to 15.0%,
a Ga2O3 component is 0 to 10.0%,
a WO3 component is 0 to 10.0%,
a TeO2 component is 0 to 15.0%,
an SnO2 component is 0 to 5.0%, and
an Sb2O3 component is 0 to 1.0%.

### Claim 5 (depends on 1)

An optical glass according to claim 1, wherein a mass sum of an Rn2O component is 1.0% to 30.0%, wherein Rn is at least one selected from the group consisting of Li, Na, and K.

### Claim 6 (depends on 1)

An optical glass according to claim 1, wherein a mass ratio of Li2O/Rn2O is no less than 0.01, wherein Rn is at least one selected from the group consisting of Li, Na, and K.

### Claim 7 (depends on 1)

An optical glass according to claim 1, wherein a mass sum of an RO component is no greater than 25.0%, wherein R is at least one selected from the group consisting of Mg, Ca, Sr, and Ba.

### Claim 8 (depends on 1)

An optical glass according to claim 1, wherein a mass sum of an Ln2O3 component is no more than 20.0%, wherein Ln is at least one selected from the group consisting of Y, La, Gd, and Yb.

### Claim 9 (depends on 1)

A preform for use in a polishing process or precision press molding, consisting of the optical glass of claim 1.

### Claim 10 (depends on 1)

An optical element consisting of the optical glass according to claim 1.