Write compensation using the thermal transfer function in an optical disk.
The theoretical basis for a write-compensation scheme is developed with a simplified thermal transfer function in an optical disk. The thermal transfer function is analytically approximated to a first-order exponential filter similar to that of an integrating circuit. A write-compensation method is then given directly by the inverse function of the filter. A simplified form of the compensation is also derived, and this is verified by experiments. This method eliminates the thermal interference and shows how to form mark edges uniformly for an arbitrary optical disk.
High-Density Magneto-Optic Disk Using Highly Controlled Pit-Edge Recording
High-density pit-edge recording on magneto-optic disks has been achieved with accurate edge control. Storage density of 0.7 µm/bit is obtained by suppressing timing jitters caused by (1) teardrop-shaped magnetic domains and (2) thermal interaction between magnetic domains.
Laser beam reading of video records.
In optical video recording the information is usually read from the disk by a scanning laser beam. We apply the theory of imaging in partially coherent light to this, situation. We assume that the disk is a thin phase object, and that the information pattern consists of tracks of a width that is small compared to the diameter of the reading spot. We obtain simple expressions for the amplitudes of the signals generated by the playback system. Also intermodulation products and cross talk between the tracks are considered.