73182803
Aug 21, 1978
May 27, 1980
OPTICAL GLASS AND GLASS BLOCK FOR OPTICAL APPLIANCES, OPTICAL AND PHOTOGRAPHIC FILTERS AND LENSES, ULTRASONIC DELAY LINE GLASS, ACOUSTO-OPTIC TELLURITE GLASS, HIGH POWER LASER GLASS, AND GLASS SUBSTRATE FOR INTEGRATED CIRCUIT PHOTOMASKS
Electrical and Scientific Apparatus