150 GB 6-layer write once disc for Blu-ray disc system

We developed a new fabrication method for multilayer optical discs for the high-throughput production of such discs. We used web coating and lamination to prepare a stacked unit. The stacked unit was a layered structure consisting of a recording layer, a UV resin layer, a recording layer, and a pressure-sensitive adhesive layer. We obtained a 20-layer disc simply by laminating the stacked units 10 times. The transmittance of the 20 recording layers was 87% owing to the high transparency of the two-photon recording material. A scanning electron microscopy (SEM) image of the disc showed a clear multilayer structure. The recording layers of the disc were recorded using a pulse laser without interlayer cross write. The thickness variation of the transparent part of the disc was within ±2 µm, and the tilt angles of the disc satisfied the Blu-ray disc (BD) specifications.

Section: Introductionmentioning

confidence: 99%

Twenty-Layer Optical Disc Fabricated by Web Coating and Lamination

Mikami

Mochizuki

Sasaki

et al. 2013

“…For write-once-type (R-type) disks, several research results have already been reported using multilayer technologies. 3,4) However, only a few research results have been reported for rewritable (RE-type) disks until 2009. The laser incident side layer required a high transmittance of as much as 70% to realize quadruple-layer optical disks.…”

Section: Introductionmentioning

confidence: 99%

Rewritable Triple-Layer Phase-Change Optical Disk Providing 100 Gbyte Capacity

Nishihara¹,

Tsuchino²,

Tomekawa³

et al. 2011

A rewritable phase-change optical disk providing a large capacity of 100 Gbyte on a 120 mm disk was first demonstrated using the multilayer Bluray Discä (BD-XL) format. The doubled capacity of this optical disk compared with that of a conventional dual-layer disk was achieved firstly by stacking triple recording layers and secondly by increasing the recording capacity per layer from 25 to 33.4 Gbyte at 33.6%. The high transmittances of 50% (middle layer) and 60% (front layer) were achieved by thinning a Ge-Sb-Te phase-change film to 7.5 and 6 nm and also by thinning a Ag-alloy film to 9 and 7 nm, respectively. An additional TiO 2 -based film formed on the Ag-alloy film was effective in improving the transmittance at 3%, compared with the structure using a conventional TiO 2 film. Furthermore, a transmittance-balanced structure was adopted for these layers in order to stabilize the recording-reading properties. To improve cyclability, ZrO 2 -Cr 2 O 3 -based interface films were provided on both sides of the phase-change film for the middle and front layers. The increase in recording capacity per layer was achieved by reducing the minimum mark length from 0.149 to 0.112 m. Since the optical changes degrade with the reductions in the mark lengths and thicknesses of the Ge-Sb-Te and Ag-alloy films, a phase-change material with a GeTe-rich composition on a GeTe-Sb 2 Te 3 pseudo-binary line was adopted for every layer to compensate it. It was confirmed that the sample disk successfully satisfies all the requirements of the BD-XL format.

“…An eight-layer ROM disk of 200 GB 1) and a six-layer write once disk of 150 GB has been reported. 2) To realize these multilayer disks, the degradation in read/write performance caused by interlayer crosstalk must be suppressed. In a multilayer disk with more than three layers, significant interlayer crosstalk is generated when the spacer-layer thicknesses are almost equal.…”

Section: Introductionmentioning

confidence: 99%

Effect of Porous Counter Electrode with Highly Conductive Layer on Dye-Sensitized Solar Cells

Rahman

Kojima

Fihry

et al. 2011

To reduce interlayer crosstalk caused by the ghost spot which appears in a multilayer optical disk with more than three information layers, a multilayer disk structure which reduces interlayer crosstalk with a wide disk-fabrication margin was proposed in which the backward reflectivity of the information layers is sufficiently low. It was confirmed that the interlayer crosstalk caused by the ghost spot was reduced to less than the crosstalk from the adjacent layer by controlling backward reflectivity. The wide disk-fabrication margin of the proposed disk structure was indicated by experimentally confirming that the tolerance of the maximum deviation of the spacer-layer thickness is four times larger than that in the previous multilayer disk.