| 摘要 |
<p>PURPOSE: To eliminate cracking or the fusion of foreign matter while preventing the fusion of the laminated thin sheet glasses to one another and to efficiently obtain high-precision flatness, in the method for flattening a sheet glass by forming a film consisting of a soln. contg. water-soluble material and surfactant on one main surface of the sheet glass. CONSTITUTION: Both sides of the one sheet glass formed by a downdrawing method or a laminate of plural glass sheets are clamped by a high-flatness compressing sheet to press the sheet glass, or the sheet glass is heated, then annealed and flattened. In this method, a film consisting of a soln. contg. water- soluble material (e.g. NaOH) and surfactant is formed on one main surface of the sheet glass, and 2-50 sheets of sheet glass are appropriately laminated. The flatness of the surface of the compressing sheet (e.g. SiC sheet) in contact with the glass sheet is made higher than that of the glass sheet. By this method, a sheet glass having 1mm-plus thickness is slightly ground to obtain a magnetic disk substrate having <=1mm thickness.</p> |
