FROSTED GLASS, MANUFACTURE OF FROSTED GLASS, PHOTOCELL WITH FROSTED GLASS SHEET AND MANUFACTURE OF SUCH PHOTOCELL

摘要

PURPOSE: To let effectively and diffusively transmits light which is normally incident on an etched surface area by etching the surface area to form a group of polyhedrally shaped recesses or adjacent surface pits, and making the surface area of the pits small to have transmissivity to the incident light and the total visual transmissivity to have specified values. CONSTITUTION: The surface area of glass is etched by a solution of hydrofluoric acid salt, a group of fluorine containing crystals substantially adjacent to each other is left, such crystals are removed, at least 30% of visible light incident perpendicularly to the surface area is diffusively transmitted, and the surface area which has a group of recessed or adjacent pits with polyhedral surface having the total visual transmissivity of visible light that is normally incident through the surface is TT-10 or more. Treatment with the hydrofluoric acid salt provides an extremely dense group of the small surface pits occupied by fluorine containing crystals formed by reaction of the glass with the salt solution, and the etched plane diffusively transmits light at a high rate without substantial loss in the total transmissivity. The TT is the total visual transmissivity of light that passes the same surface prior to etching separated as a persentage of the total incident visible.