Hoya Assigned Two Patents

Magnetic-disk glass substrate, substrate intermediate, and method for manufacturing
Hoya corporation, Tokyo, Japan, has been assigned a patent (11710505) developed by Azuma; Shuhei, Hung Yen Province, Vietnam, for “disk glass substrate, substrate intermediate, and method for manufacturing.“

The abstract of the patent published by the U.S. Patent and Trademark Office states: “A magnetic-disk glass substrate contains an alkaline earth metal component as a glass composition and includes a pair of main surfaces, and an outer circumferential side edge surface that is a mirror surface. The outer circumferential side edge surface includes a surface having a roughness percentage of 40% or more and 68% or less when a bearing ratio of a roughness cross-sectional area is 50% in a bearing ratio curve of roughness cross-sectional areas obtained when a surface roughness of the outer circumferential side edge surface obtained after the outer circumferential side edge surface is etched by 2.5 μm is measured. A glass transition point of the glass composition that constitutes the magnetic-disk glass substrate is 700° C. or more. The glass composition that constitutes the magnetic-disk glass substrate is alkali-free glass.”

The patent application was filed on 2021-12-10 (17/548008).

Manufacturing ring-shaped glass spacer
Hoya corporation, Tokyo, Japan, has been assigned a patent (11705158) developed by Takano, Masao, Akishima, Japan, and Eda, Shinji, Hung Yen Province, Vietnam, for a “method for manufacturing ring-shaped glass spacer.“

The abstract of the patent published by the U.S. Patent and Trademark Office states: “A method for manufacturing the ring-shaped glass spacer to be arranged in contact with a magnetic disk in a hard disk drive apparatus, including: preparing a ring-shaped glass blank, and grinding main surfaces of the ring-shaped glass blank by using grinding pads that include diamond particles as fixed abrasive particles.”

The patent application was filed on 2022-01-31 (17/589824).