Title:
円盤形状のガラス素板の製造方法、及び磁気ディスク用ガラス基板の製造方法
Document Type and Number:
Japanese Patent JP6783401
Kind Code:
B2
Abstract:
A glass blank is cut out from a glass plate by forming a crack starting portion inside the glass plate by moving a first laser beam relative to the glass plate such that a focal position of the laser beam is located in an inner portion of the glass plate in its thickness direction and the focal position forms a circle when viewed from a surface of the glass plate, then causing cracks to develop from the crack starting portion toward main surfaces of the glass plate, and splitting the glass plate to separate, from the glass plate, a glass blank that includes a separation surface having an arithmetic average surface roughness Ra smaller than 0.01 μm and a roundness not larger than 15 μm. Thereafter, main surfaces of the glass blank are ground or polished.
Inventors:
Shuhei Azuma
Application Number:
JP2019569096A
Publication Date:
November 11, 2020
Filing Date:
January 28, 2019
Export Citation:
Assignee:
HOYA CORPORATION
International Classes:
C03B33/09; B23K26/361; B23K26/53; B24B1/00; B24B7/24; B24B37/08; C03C19/00; G11B5/73; G11B5/84
Domestic Patent References:
| JP2009087409A | ||||
| JP2009241154A | ||||
| JP2015083320A | ||||
| JP2015076115A | ||||
| JP2015181085A | ||||
| JP2017508691A | ||||
| JP2012218103A | ||||
| JP2017511777A |
Foreign References:
| WO2015002152A1 |
Attorney, Agent or Firm:
Global IP Tokyo Patent Business Corporation