Optimization of Multilayered Media Structure for Three-Dimensional Optical Memory

Abstract

We analyzed the optimum structure of recording media for a reflection confocal readout system of three-dimensional optical memory. In this analysis, we discuss the overlapping regions of the coherent transfer function of the reflection confocal readout system and the spatial frequency distribution of recorded bits. The intensity of the readout signal is proportional to the multiplication of the three-dimensional distribution of the coherent transfer function of the reflection confocal system and the spatial frequency distribution of recorded bits. We optimized film thickness to increase the signal from recorded bits. It was found that the readout signal increased twentyfold by optimization of film thickness. In addition, we optimized the relative refractive index of recording media by light propagation analysis of multilayered media. In the case of optimal film thickness, the ratio of refractive indices between recording layers and transparent layers should be 1.01 for obtaining maximum reflection.

Twenty-Layer Optical Disc Fabricated by Web Coating and Lamination

“…Several studies of laminate multilayer discs have been reported. 23,24) In these studies, recording and PSA layers were stacked alternately. Hence, there are interface reflections between the recording layer and the PSA layer on both sides of the recording layer.…”

Optically High Spatial Resolution Obtained Using Super-Resolution Near-Field Structure Disk System

“…Therefore, multilayer disks and three-dimensional memories have been investigated to attain large data capacities. [1][2][3][4] A large space is required between recording layers in order to avoid interlayer crosstalk, and the optical absorption in each recording layer limits the number of layers. Therefore, a new record and retrieve system is required to fabricate 1 TB optical disks for data storage hierarchy requested by the Information and Communication Technology (ICT) Society.…”

Dynamic Layer Detection of Rotating Multilayered Optical Memory

“…[1][2][3][4][5][6][7][8] We have also developed a 3-D multilayered optical memory, in which photosensitive layers and transparent layers are piled up alternately. 9,10) Because we use pressure-sensitive adhesives (PSAs) as transparent layers, we can easily fabricate multilayered structures. We demonstrated recording and reading bit data in a multilayered medium that contains twenty recording layers.…”