US 12,012,349 B2
Glass fine particle deposit and method for manufacturing glass preform
Masatoshi Hayakawa, Osaka (JP); Masumi Ito, Osaka (JP); and Tatsuya Konishi, Osaka (JP)
Assigned to SUMITOMO ELECTRIC INDUSTRIES, LTD., Osaka (JP)
Appl. No. 17/600,648
Filed by SUMITOMO ELECTRIC INDUSTRIES, LTD., Osaka (JP)
PCT Filed Mar. 30, 2020, PCT No. PCT/JP2020/014629
§ 371(c)(1), (2) Date Oct. 1, 2021,
PCT Pub. No. WO2020/203985, PCT Pub. Date Oct. 8, 2020.
Claims priority of application No. 2019-071333 (JP), filed on Apr. 3, 2019.
Prior Publication US 2022/0162111 A1, May 26, 2022
Int. Cl. C03B 37/018 (2006.01)
CPC C03B 37/018 (2013.01) [C03B 2207/70 (2013.01)] 5 Claims
OG exemplary drawing
 
1. A method for manufacturing a glass preform, the method comprising:
manufacturing a transparent glass preform by heating, at a first temperature, a glass fine particle deposit in which a pH of glass fine particles on a surface of the glass fine particle deposit is 5.5 or more and less than 8.5; and
measuring the glass fine particle surface of the deposit by a SCI (Specular Component Include) method using a spectrophotometer and determining whether a color difference ΔE*ab with respect to a white calibration plate is 5 or more,
wherein in a case where the color difference ΔE*ab is determined to be 5 or more, the glass fine particle deposit is heated in an oxygen-containing atmosphere having an oxygen content of 10 vol % or more at a second temperature lower than the first temperature, and then the heating of the glass fine particle deposit at the first temperature is performed, and
wherein in a case where the color difference ΔE*ab is determined to be less than 5, the heating of the glass fine particle deposit at the first temperature is performed without heating the glass fine particle deposit in the oxygen-containing atmosphere.