摘要:
Casting a glass major portion of a multifocal lens blank over a glass segment portion of the blank or impressing the segment into the major portion during or immediately after casting. The glass for the major is selected to coincide in viscosity with the segment glass within a range of 105 to 109 poises at least at one temperature, and that above the crossover point the viscosity of the segment glass is higher than the viscosity of the major glass at the same temperature.
摘要:
PHOSPHATE GLASSES FOR OPTICAL APPLICATIONS ARE PRODUCED BY AN IMPROVED METHOD IN WHICH THE CERAMIC UTENSILS UTILIZED IN THE PRODUCTION OF THE GLASS ARE FORMED OF TIN OXIDE.
摘要:
Tubing of short glass is provided by casting the glass in a tubular mold under a vacuum. The basic principle of operation is similar to that utilized in the Torricelli barometer. That is, pressure on the surface of the melt forces the molten glass into a tubular mold to a height determined by the difference in pressure between the ambient over the surface of the melt and that remaining in the mold.
摘要:
Laser glass which has a low loss coefficient and is highly resistant to internal damage resulting from inclusions is produced in a ceramic crucible where the crucible and the associated ceramic stirrer are prepared such that the surfaces thereof are essentially free of reducing components.
摘要:
THE INVENTION RELATES TO A SERIES OF NEW GLASSES OF THE LOW CROWN AND LOW FLINT TYPE BUT WITH REFRACTIVE INDICES LOWER THAN THOSE PREVIOUSLY OBTAINABLE AND WITH IMPROVED SPECTRAL TRANSMISSON. THE CRUX OF THE INVENTION PROVIDES FOR THE CONTROLLED INCLUSION OF AN EFFECTIVE AMOUNT OF MERCURY NITRATE IN GLASS BATCH COMPOSITIONS.