| 摘要 |
PROBLEM TO BE SOLVED: To provide a glass substrate for a magnetic disk which has excellent quality, such as high flatness adequate as a magnetic disk and is formed with projections by irradiating its front surface with a laser beam so as to form the projections as texture. SOLUTION: The glass substrate 1 for the magnetic disk is 20 to 2000mm<-1> in the coefft. of light absorption of the glass at a wavelength 266nm of the laser beam. The glass contains components, such as silicon oxide, aluminum oxide and lithium oxide respectively having prescribed compsns. to allow the production by a floating method. The projections of a projecting shape are formed on the surface of the glass substrate 17 by irradiation with the laser beam. The relation between the content of the iron in the glass and the coefft. of absorption of the glass and the relation between the coefft. of absorption of the glass and the height of the projections are linear. The relation between the output of the laser beam and the height of the projections is exponential under a low-energy region. |
