Loading patent…
AssigneeTosoh Quartz Corporation
InventorsChiemi Ito, Takeshi Mutou, Minoru Kuniyoshi, Mutsumi Asano, Atsushi Ando
Estimating the term…
A large sized opaque quartz glass ingot having an excellent heat ray shielding property, an outstanding light blocking property, high mechanical strength and small roughness of a baked finished smooth surface. The shape of bubbles inside the quartz glass are almost complete spheres and the average particle size of the bubbles is 1 μm or less, such that the strength of the opaque quartz glass ingot is increased as the stress concentration at the edges of the bubbles is eliminated and an increase of surface roughness caused by baking is alleviated.
An opaque quartz glass wherein an average diameter of bubbles contained therein is 1 μm or less, a density is 2.16 to 2.19 g/cm3, a whiteness is 90% or more at a thickness of 10 mm, and a reflectance of light of wavelength from 0.2 to 3 μm at a thickness of 3 mm is above 85%, wherein the average diameter of the bubbles is determined by cutting a sample of the opaque quartz glass to provide a cut surface, observing at least 20 bubbles on the cut surface by using a scanning electron microscope, processing obtained images from the scanning electron microscope of the at least 20 bubbles and measuring an area “A” of each bubble wherein an average value “D” of the bubbles is determined by the following equation (1):
A method of manufacturing an opaque quartz glass, comprising the steps of:
Dependencies are inferred from the claim text.