Kabushiki Kaisha Ohara

Kabushiki Kaisya Ohara

Futoshi Ishizaki

Naoyuki Goto

Katsuhiko Yamaguchi

Muneo Nakahara

Hisao Yatsuda

Masashi Maekawa

Goro Enomoto

Akimasa Yamagata

Kenji Sugizaki

Hideo Yasui

Hiroshi Shishido

A globular glass manufacturing apparatus includes: a flow nozzle to flow a molten glass in a form of continuous flow, a collection tank to collect droplet-like glass gobs deformed from the molten glass flowing in a form of continuous flow during fall. Further, the globular glass manufacturing apparatus comprises a gas nozzle to shift one or both of falling trajectories of the glass gobs neighboring above and below by blowing gas to the glass gobs or sucking the glass gobs, wherein the gas nozzle rotates in which the center is on falling trajectory of the glass gobs.

Globular glass manufacturing apparatus and method for manufacturing the globular glass

Glass-ceramic for information recording disks have a crystalline structure suitably used for substrate materials and the like for magnetic disks and magneto-optic disks as well as have improved surface characteristics obtained by polishing the glass, and besides the base glass thereof is excellent in melting properties and moldability thereof. The base glass composition consists essentially of ingredients of SiO.sub.2 -Al.sub.2 O.sub.3 -ZnO-MgO-CaO-SrO-BaO-TiO.sub.2 system. The main crystalline phase of the glass-ceramic produced by heat-treating the base glass having a viscosity of log .eta.=3.0 poise or less at 1250.degree. C. is gahnite, a size of the crystal grain is within a range of from 50 to 1000 Angstrom, and a degree of surface roughness (Ra) of the polished glass-ceramic is within a range of from 0.5 to 9.0 Angstrom.

Glass-ceramic for information recording disk

An optical glass which is a SiO.sub.2 -Nb.sub.2 O.sub.5 -R'.sub.2 O (where R' is an alkali metal element)-F system of a specific composition range exhibits optical constants of a refractive index (Nd) of about 1.52-1.67 and an Abbe number (.upsilon. d) of about 32-50, is free of PbO and has an improved light transmissivity.

High dispersion optical glass

An optical glass which is a SiO.sub.2 --B.sub.2 O.sub.3 --(TiO.sub.2 +ZrO.sub.2)--SrO--BaO--R'.sub.2 O system of a specific composition range exhibits optical constants of a refractive index (Nd) of 1.57-1.75 and Abbe number (.nu.d) of 30-55, is free of PbO and has improved stability against devitrification and tinting and improved chemical durability.

Optical glass

Growing community of inventors

Sagamihara, Japan

Futoshi Ishizaki