Optical recording medium having thin protective layer and two-dimensionally aligned code words and recording/reproducing apparatus employing the same

摘要

An optical recording medium includes a substrate, a recording layer formed on the substrate and a transparent protective layer applied to the recording layer. By reducing the thickness of the transparent protective layer to less than 1 mm, it is possible to make the numerical aperture (NA) of an objective lens larger. This structure can achieve a high recording density. Such a thin transparent protective layer causes signal degradation due to dust adhered to the surface of the recording layer and the generation of frequent errors. However, such frequent errors can be corrected by specifying the interleave length and the number of parity symbols added to a code word that constitutes the product code.