Hoya Assigned Two Patents

Non-magnetic substrate for magnetic disk
Hoya Corp., Tokyo, Japan, has been assigned a patent (11,031,036) developed by Osakabe, Kinobu, Tokorozawa, Japan, for “non-magnetic substrate for magnetic disk, and magnetic disk.“

The abstract of the patent published by the U.S. Patent and Trademark Office states: ”A non-magnetic substrate for a magnetic disk includes a substrate main body having two opposing main surfaces, and a metal film that is provided on the main surfaces and is made of a material having a loss factor of 0.01 or more. The non-magnetic substrate has a thickness (T+D) of 0.700 mm or less, the thickness (T+D) being the sum of a thickness T of the substrate main body and a thickness D of the metal film, and a ratio D/T of the thickness D of the metal film to the thickness T of the substrate main body is 0.025 or more.”

The patent application was filed on April 2, 2018 (Appl. No.16/499,200).

Magnetic-disk glass substrate
Hoya Corp., Tokyo, Japan, has been assigned a patent (11,024,335) developed by Azuma, Shuhei, Akishima, Japan, for a “magnetic-disk glass substrate.“

The abstract of the patent published by the U.S. Patent and Trademark Office states: ”A magnetic-disk glass substrate containing an alkali metal component as a glass composition 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 with a roughness percentage that is 40% or more 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 by etching the outer circumferential side edge surface by 2.5 .mu.m is measured.”

The patent application was filed on June 21, 2018 (Appl. No.16/014,687).