METHOD FOR PRODUCING HOLLOW PARTICLES, HOLLOW PARTICLE, ANTIREFLECTION COATING, AND OPTICAL ELEMENT

摘要

A hollow particle and a method for producing hollow particles are provided. The shell of the particle(s) is a continuous layer containing magnesium fluoride and thus is strong. A hollow particle has a continuous shell containing magnesium fluoride and an at least partially removed hollow core. A method for producing hollow particles includes forming core-shell particles having a core particle and a continuous shell containing magnesium fluoride and removing at least a portion of the core particle from the core-shell particles to produce a hollow core. The core-shell particles can be formed by adding an aqueous solution of a magnesium salt and an aqueous solution containing fluoride ions to an aqueous dispersion containing the core particles at a temperature of 10 degrees Celsius to 30 degrees Celsius, both inclusive, and then heating the combined liquid at a temperature of 50 degrees Celsius to 80 degrees Celsius, both inclusive.