PURPOSE: To improve the coating performance of an undercoating to a substrate and to obtain a uniform undercoating layer for an optical information recording medium containing a pair of substrates which are opposite to each other with their recording layes set inside, by forming the substrates into special form.
CONSTITUTION: A circular projection part 5 is provided to a transparent plastic substrate at the fringe of the center part and at the side where an undercoating layer 7 and a recording layer 2 are provided. At the same time, a circular recess part 8 is formed at the outer fringe part of the substrate 1. A pair of such substrates 1 and 1 are joined together through the face of the part 5 so that the layers 2 and 2 are opposite to each other via a space 4. At the same time, a circular recess part including the parts 8 and 8 is sealed up with a spacer 9. Thus an optical information recording medium is obtained. For the production of this recording medium, the extra undercoating is discharged through the part 8 when the layer 7 is formed to the substrate by a spin coating process. Thus the layer 7 of an even thickness can be easily formed.
TAKAHASHI YOUNOSUKE
HASEGAWA EIICHI
