Dynamic Layer Detection of Rotating Multilayered Optical Memory

Abstract

We fabricated disc-type multilayered media with several refractive indices of pressure-sensitive adhesives for dynamic layer detection. We modified a commercially available disc tester in order to obtain two types of signal; one is the confocal signal and the other is the astigmatic signal. The confocal signal provides sufficient signal to detect recording layers, but the astigmatic signal is not useful because the reflected signals from the internal layers are too small. The confocal detection also provides sufficient signal for rotating discs. We found that the intensities of the reflected signals of rotating multilayered media were of the same level as those of the fixed multilayered media. The reflections from the multilayered media can be used as focus-servo signals.

Decoupled direct tracking control system based on use of a virtual track for multilayer disk with a separate guide layer

“…A promising approach to green archival storage is the use of optical disks due to their large capacity, low running cost, and longevity. While their capacity can be readily expanded by increasing the number of recording layers, [1][2][3][4][5][6][7][8][9][10] the groove structure needed for tracking control increase the disk fabrication cost. 11) For example, as shown in Fig.…”

Reduction of Interlayer Crosstalk of Multilayer Optical Disc by Using Phase-Diversity Homodyne Detection

“…Reflecting such a situation, multilayer discs holding more than 10 layers have been widely studied in the laboratory stage. [3][4][5][6][7][8][9][10][11][12][13] Ogasawara et al reported 16and 20-layer read-only discs 5) and 16-layer write-once discs 10) with the same density as BD or BDXLÔ. In ref.…”

Parallel Signal Readout for Roll-Type Optical Advanced Memory

“…We have developed a multilayered optical memory using a multilayered medium that was fabricated with a laminating process. [13][14][15][16] Because the medium was a stack of films, the thickness of each layer of the multilayered optical memory is uniform.…”