Glass material for a substrate, glass substrate, and information recording medium employing the same
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
G11B-005/82
C03C-003/093
출원번호
US-0852286
(2004-05-25)
우선권정보
JP-0166548 (2002-06-07)
발명자
/ 주소
Kawai, Hideki
출원인 / 주소
Minolta Co., Ltd.
대리인 / 주소
Burns, Doane, Swecker &
인용정보
피인용 횟수 :
2인용 특허 :
14
초록▼
A glass material for a substrate, or a glass substrate, consists essentially of the following glass ingredients: from 45 to 70 wt % of SiO2, from 1 to 10 wt % of Al2O3, from 0.5 to 8 wt % of B2O3, from 7 to 20 wt % of Li2O+Na2O+K2O, from 0.1 to 10 wt % of MgO, from 0.1 to 10 wt % of CaO, from 1 to 1
A glass material for a substrate, or a glass substrate, consists essentially of the following glass ingredients: from 45 to 70 wt % of SiO2, from 1 to 10 wt % of Al2O3, from 0.5 to 8 wt % of B2O3, from 7 to 20 wt % of Li2O+Na2O+K2O, from 0.1 to 10 wt % of MgO, from 0.1 to 10 wt % of CaO, from 1 to 15 wt % of MgO+CaO, from 0.5 to 10 wt % of TiO2, from 0.5 to 10 wt % of ZrO2, from 0 to 5 wt % of ZnO, and from 0 to 8 wt % of La2O3. The glass material, or the glass substrate, has uniform composition between at the surface and in the interior and has an amorphous structure. With this design, it is possible to obtain high mechanical strength without strengthening treatment, a linear thermal expansion coefficient close to motor components, and excellent chemical durability.
대표청구항▼
1. A glass substrate having uniform composition both at a surface and an interior thereof and having an amorphous structure, wherein the glass material fulfills the following conditions:(A/B)×E×107?30 62×10?7?A?82×10?7 B?250 ppb (per 2.5-inch disk) 85?E?95 whereA represents a linear thermal expansio
1. A glass substrate having uniform composition both at a surface and an interior thereof and having an amorphous structure, wherein the glass material fulfills the following conditions:(A/B)×E×107?30 62×10?7?A?82×10?7 B?250 ppb (per 2.5-inch disk) 85?E?95 whereA represents a linear thermal expansion coefficient (/° C.); B represents alkali elution (ppb) (per 2.5-inch disk); and E represents a Young's modulus (GPa); wherein the glass substrate is produced by undergoing a polishing step and then a cleaning step in which the glass substrate is cleaned with at least one of a pure water liquid, an acidic liquid, and an alkaline liquid, and a surface roughness Ra after the polishing step and a surface roughness Ra′ after the cleaning step fulfill both of the following conditions: Ra′/Ra?1.5, and Ra?1.0 nm. 2. An information recording medium comprising:a glass substrate; and a magnetic film formed on top of the glass substrate directly or with one or more primer and/or protective layers sandwiched in between, wherein the glass substrate has uniform composition both at a surface and an interior thereof, has an amorphous structure, and fulfills the following conditions: (A/B)×E×107?30 62×10?7?A?82×10?7 B?250 ppb (per 2.5-inch disk) 85?E?95 whereA represents a linear thermal expansion coefficient (/° C.); B represents alkali elution (ppb) (per 2.5-inch disk); and E represents a Young's modulus (GPa); wherein the glass substrate is produced by undergoing a polishing step and then a cleaning step in which the glass substrate is cleaned with at least one of a pure water liquid, an acidic liquid, and an alkaline liquid, and a surface roughness Ra after the polishing step and a surface roughness Ra′ after the cleaning step fulfill both of the following conditions: Ra′/Ra?1.5, and Ra?1.0 nm.
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이 특허에 인용된 특허 (14)
Zou Xuelu,JPX ; Toratani Hisayoshi,JPX, Disc substrates for information recording discs and magnetic discs.
Akihiro Koyama JP; Shoichi Kishimoto JP; Junji Kurachi JP; Nobuyuki Yamamoto JP, Glass composition and substrate for information recording media comprising the same.
Fukushima, Masato; Sakaguchi, Ryuji; Matsumura, Yukihisa, Magnetic recording medium, process for producing the same, and magnetic recording and reproducing apparatus.
Takahashi, Kouji; Miyamoto, Takemi; Tomiyasu, Hiroshi; Hata, Genshichi; Yokoyama, Tomotaka, Substrate for an information recording medium, information recording medium using the substrate and method of producing the substrate.
Nagashima, Tatsuo; Nagai, Kensuke; Nakashima, Tetsuya; Maeda, Kei, Glass for data storage medium substrate, glass substrate for data storage medium and magnetic disk.
Nagashima, Tatsuo; Nagai, Kensuke; Nakashima, Tetsuya; Maeda, Kei, Glass for data storage medium substrate, glass substrate for data storage medium and magnetic disk.
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