Data carrier disk for e.g. compact disk (CD) has carrier layers separated by interfaces, with a laser beam focus system to scan the data optically from selected layers with a significant increase in data storage capacity

摘要

The data store to take optically-readable data is a disk (Sp) formed by overlaid layers (P1-PN) of data carriers of separate dephasing. They are separated by transparent layers (C1-CN) so that the light beam (Fl) can be focused on the required layer to scan the stored data through the overlaid layers. The disk to store data has a dephasing through the stored data which is less than several one-tenths of a radian. Each data carrier layer has an interface between two dielectric levels with different refraction indexes which differ by several percentage points. The stored data elements are constituted by the relief structures of the interfaces, with a depth of one-hundredth of a micrometer. The interfaces alternate so that the signs of the index alternate between one interface and the following interface. Each interface has calibrated micro-balls or micro-cylinders as spacers, to maintain a given gap between the data carrier levels. The dielectric levels are of a polymer material, all of the same polymer with varied plasticizer additives to give an individual refraction index. One outer surface of the data store disk is metallized to give reflection towards the other outer surface. Independent claims are also included for: (1) a data storage disk production process, where a layer of a monomer which can be photo-polymerized is laid over a substrate. A press die is applied to the layer, carrying the data for recording in the matching carrier level to spread the material. The material is polymerized by a suitable light source, and the process is repeated for each layer in the disk; and (2) an optical disk data carrier system with a light source to give a light beam focused at the data carrier level to be read. A receiver gathers the light beam after passing through, with detectors to convert the reception into a reading signal. A drive moves the light source in relation to the disk. The detectors work in a remote field, together with a filter to detect only the low frequency spatial components of the transmitted light beam.