US Patent Issued to HOYA on Nov. 25 for "Glass for magnetic recording medium substrate or for glass spacer for magnetic recording and reproducing apparatus" (Japanese Inventors)

ALEXANDRIA, Va., Nov. 25 -- United States Patent no. 12,479,755, issued on Nov. 25, was assigned to HOYA Corp. (Tokyo).

"Glass for magnetic recording medium substrate or for glass spacer for magnetic recording and reproducing apparatus" was invented by Koichi Sato (Tokyo) and Kazuaki Hashimoto (Tokyo).

According to the abstract* released by the U.S. Patent & Trademark Office: "A glass is an amorphous oxide glass. An SiO2 content ranges from 56 mol % to 80 mol %, an Li2O content is 2.00 mol % or less, a B2O3 content ranges from 0 mol % to 4 mol %, a total content of MgO and CaO (MgO+CaO) ranges from 9 mol % to 40 mol %, and the oxide glass has a specific gravity of 2.75 g/cm3 or less, and a glass transition temperature of 650deg C. or high...