Title:
METHOD FOR PRODUCING GLASS SUBSTRATE FOR INFORMATION RECORDING MEDIUM
Document Type and Number:
WIPO Patent Application WO/2011/121913
Kind Code:
A1
Abstract:
When repeatedly using colloidal silica as a polishing material when subjecting a glass material to precision polishing, a limitation on the frequency in which the colloidal silica can be repeatedly used is removed by preventing the colloidal silica from gelling, thereby dramatically increasing productivity. Disclosed is a method for producing a glass substrate for an information recording medium, which involves a precision polishing step in which a glass material, which has 0.5ng/cm2 or less of iron attached to the surface and a surface roughness (Ra) of 1nm or less, is subjected to precision polishing under acidic conditions using a polishing material containing colloidal silica. Also disclosed is a glass substrate for an information recording medium which is produced by means of the aforementioned method for producing a glass substrate for an information recording medium.
Inventors:
NAKAE, Hazuki (INC. 2970, Ishikawa-machi, Hachioji-sh, Tokyo 05, 〒1928505, JP)
Application Number:
JP2011/001498
Publication Date:
October 06, 2011
Filing Date:
March 15, 2011
Export Citation:
Assignee:
KONICA MINOLTA OPTO, INC. (2970, Ishikawa-machi Hachioji-sh, Tokyo 05, 〒1928505, JP)
コニカミノルタオプト株式会社 (〒05 東京都八王子市石川町２９７０番地 Tokyo, 〒1928505, JP)
コニカミノルタオプト株式会社 (〒05 東京都八王子市石川町２９７０番地 Tokyo, 〒1928505, JP)
International Classes:
G11B5/84; B24B1/00; B24B37/00
Attorney, Agent or Firm:
KOTANI, Etsuji et al. (Osaka Nakanoshima Building 2nd Floor, 2-2 Nakanoshima 2-chome, Kita-ku, Osaka-sh, Osaka 05, 〒5300005, JP)
Claims: