Rare earth metal-doped quartz glass and method for producing the same

Patent metadata

Field	Value
Publication number	US-10336645-B2
Application number	US-201715634634-A
Country	US
Kind code	B2
Filing date	Jun 27, 2017
Priority date	Jun 28, 2016
Publication date	Jul 2, 2019
Grant date	Jul 2, 2019

Abstract

A method for producing rare earth metal-doped quartz glass includes the steps of (a) providing a blank of the rare earth metal-doped quartz glass, and (b) homogenizing the blank by softening the blank zone by zone in a heating zone and by twisting the softened zone along a rotation axis. Some rare earth metals, however, show a discoloration of the quartz glass, which hints at an unforeseeable and undesired change in the chemical composition or possibly at an inhomogeneous distribution of the dopants. To avoid this drawback and to provide a modified method which ensures the production of rare earth metal-doped quartz glass with reproducible properties, during homogenization according to method step (b), the blank is softened under the action of an oxidizingly acting or a neutral plasma.

First claim

We claim:

1. Method for producing rare earth metal-doped quartz glass, the method comprising the steps of:
(a) providing a blank of the rare earth metal-doped quartz glass; and
(b) homogenizing the blank by softening the blank zone by zone in a heating zone and by twisting the softened zone along a rotation axis,
wherein during homogenization according to method step (b), the blank is softened under the action of an oxidizingly acting or neutral plasma.

2. Method according to claim 1 , wherein an oxygen-containing gas is supplied to the plasma.

3. Method according to claim 1 , wherein a microwave atmospheric pressure plasma or an inductively coupled plasma is generated.

4. Method according to claim 1 , wherein a plasma gas which is free of hydrogen or hydrogenous compounds is supplied to the plasma.

5. Method according to claim 1 , wherein a rare earth metal-doped quartz glass is generated that contains rare earth metal oxide in a concentration of 0.002 to 10 mole % and has a fluctuation in the refractive index δΔn which based on a mean refractive index difference Δn with respect to undoped quartz glass is less than 10%, and has a bubble content represented by a total bubble cross section (TBCS) value of less than 10.

6. Method according to claim 1 , wherein a rare earth metal-doped quartz glass is produced that has a mean chlorine content in the range of 300 to 3000 wt. ppm.

7. Method according to claim 2 , wherein a microwave atmospheric pressure plasma or an inductively coupled plasma is generated.

8. Method according to claim 2 , wherein a rare earth metal-doped quartz glass is produced that has a mean chlorine content in the range of 300 to 3000 wt. ppm.

9. Method according to claim 3 , wherein a rare earth metal-doped quartz glass is produced that has a mean chlorine content in the range of 300 to 3000 wt. ppm.

10. Method according to claim 5 , wherein the rare earth metal-doped quartz glass has a mean hydroxyl group content between 0.1 and 100 wt. ppm.

11. Method according to claim 6 , wherein the rare earth metal-doped quartz glass has a mean hydroxyl group content between 0.1 and 100 wt. ppm.

Assignees

• Heraeus Quarzglas

Inventors

• Baierl Hardy
• Grimm Stephan
• Schuster Kay
• Dellith Jan
• Langner Andreas
• Schoetz Gerhard
• Lehmann Walter
• Kayser Thomas

Classifications

• C03B2201/12

  doped with fluorine (C03B2201/14 takes precedence) · CPC title

• H01S3/17

  amorphous, e.g. glass · CPC title

• C03B19/066 Primary

  for the production of quartz or fused silica articles (other processes specially adapted for the production of quartz or fused silica articles C03B20/00) · CPC title

• C03B2201/36

  doped with rare earth metals and aluminium, e.g. Er-Al co-doped · CPC title

• C03B20/00

  Processes specially adapted for the production of quartz or fused silica articles {, not otherwise provided for (C03B19/01, C03B19/066, C03B19/106, C03B19/12, C03B19/14, C03B37/00 take precedence)} · CPC title