PRODUCTION OF OXIDE COATING

PROBLEM TO BE SOLVED: To form oxide coating at a high speed without generating splash and to eliminate the generation of defective products caused by splash, at the time of producing oxide coating by vacuum deposition, by using oxide having specified particle size as an evaporating material and executing evaporation. SOLUTION: As the oxide, MgO, SiO2 , TiO2 , ZrO2 , Al2 O3 or the like are used. For regulating the rate of precipitating MgO to the one higher than the conventional case, MgO particles having about >=3mm particle size are used. For regulating the same to approximately double that in the conventional case or above, MgO having about >=4mm particle size is used. Furthermore, for regulating the same to approximately three times that or above, an evaporating raw material having about >=7mm shall be used. In this way, by using the evaporating material in which MgO particles having large particle size are contained, the frequency of the generation of splashes can be suppressed or the generation thereof can be eliminated.