The optical recording medium of this invention includes: a first substrate having a first information surface; a semitransparent reflection film formed on the first information surface of the first substrate; a second substrate having a second information surface; a reflection film formed on the second...http://www.google.de/patents/US6143426?utm_source=gb-gplus-sharePatent US6143426 - Optical recording medium having dual information surfaces
Optical recording medium having dual information surfaces
