METHOD FOR MANUFACTURING SYNTHETIC QUARTZ GLASS FOR OPTICAL USE, SYNTHETIC QUARTZ GLASS FOR OPTICAL USE AND ANNEALING FURNACE

摘要

PROBLEM TO BE SOLVED: To provide a method for manufacturing synthetic quartz glass having less than 0.5 nm/cm birefringence in the direction of light transmittance and good refractive index distribution for optical use without reducing productivity, and to provide the synthetic quartz glass for optical use and an annealing furnace suitable for the manufacturing method.

SOLUTION: The temperature of a pillar-shaped preform of synthetic quartz glass for optical use is raised to 800-1,200°C, held for a fixed time, and lowered each at 2-50°C/h but with 1-20°C of the temperature difference between the temperature of the optical transmission surface and the temperature of peripheral side surface of the synthetic quartz glass preform.

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