MULTI LAYER DATA RECORD MEDIA, HAVING PLANARITY EQUAL TO SINGLE LAYER ONE, AND A DATA RECORD AND REGENERATION APPARATUS, ENHANCING RAPID REGENERATION IN SPITE OF USING OBJECT LENS WITH NUMERICAL APERTURE LARGER THAN 0.8

摘要

PURPOSE: A multi layer data record media and a data record and regeneration apparatus are provided to record or regenerate data on or from two more record layers interoperable with a single layer disc. CONSTITUTION: The record media comprises a cover layer, the first record layer and the second record layer. The cover layer has a refraction index at a beam incidence side, and a thickness. The first and the second record layer are formed sequentially from the beam incidence side. The second record layer is positioned at one optical distance(d1) from the beam incidence side where d1=nxt, and the first record layer is positioned at another optical distance(d2) from the beam incidence side where d2nxt. Physical address data is recorded sequentially from the second record layer to the first record layer.