GUIDE LAYER SEPARATION TYPE OPTICAL RECORDING MEDIUM, OPTICAL RECORDING MEDIUM DRIVE DEVICE AND METHOD FOR ACCESSING RECORDING LAYER

摘要

A guide layer on which a guide track is formed and a plurality of recording layers are so stacked as to be separated from each other, layer position information areas in which position information of the recording layers is shown on the guide track for each recording layer are formed in ranges different from each other in the guide layer.  The recording layer is provided with a pre-format area in which a predetermined signal is recorded on a recording track along the guide track, wherein the pre-format area in each recording layer is set in an area corresponding to the layer position information area.  An optical recording medium drive device and a method for accessing a recording layer judge whether a reproducing signal is acquired or not in accordance with a detection level by a recording and reproducing optical system of reflected light from the pre-format area, acquire the position information for any one out of the plurality of the recording layers in accordance with a detection level by a servo optical system of reflected light from the layer position information areas, and make a second laser beam access a desired recording layer out of the plurality of the recording layers in accordance with a judging result and position information of the reproducing signal.