| 摘要 |
PURPOSE:To obtain an optical master disk having good accuracy by changing the power of an exposing plane by a radius region, thereby making a groove shape uniform within the plane. CONSTITUTION:The recording luminous fluxes of a recording light source on a recording master disk are condensed by a condenser lens and the focus state of this condenser lens is controlled by a control means to modulate control light according to information signals. The recording light power P is set at P=alphar(alpha>0, r; radius) and the information signals to change alpha by the radius region are recorded. As a result, the groove shapes (groove width and groove depth) of prepits and pregrooves are made uniform within the plane and the optical master disk having the good accuracy is obtd. |
