Japanese Pioneer and Memory-Tech Corp. have jointly developed a high-capacity optical disc for data archiving with a capacity of 256 GB on a single side and with the use of double-sided disc technologies, its capacity can be expanded up to 512 GB.
The companies hope that the new disc could be used
for digital archiving, as it offers the advantages of lower maintenance costs and reliability compared with other storage technologies.
The high-capacity optical disc employs a guide layer-separated multi-layer disc structure which separates the recording layers and guide layers.
This approach offers a simplified disc structure. The guide grooves (tracks) present in the recording layers of conventional optical discs do not exist, and the adoption of a guide layer-separated multi-layer disc structure separately establishes dedicated guide layers for the guide grooves.
This makes it easier to stack recording layers, essential for expanding disc capacity, as well as reducing disc manufacturing costs and achieving improved manufacturing yields.
By stacking eight recording layers capable of recording 32 GB per layer, recording capacity of 256 GB on the single side of a disc has been achieved. In addition, with the use of double-sided disc technologies, a capacity of up to 512 GB on a single disc can be achieved. High-speed recording is also supported, allowing recording at up to 4x speed (Blu-ray Disc format standard).
In addition, the optical disc recording devices employ the same optical specifications (405nm recording laser wavelength, 0.85 NA objective lens, etc.), Reed-Solomon error correction method and 17PP encoding method as Blu-ray Disc drives. This means that the developed optical discs recorded using a compliant recording device can be played back on Blu-ray Disc compliant drives, although some pickup and firmware modifications are required.
Disc specifications |
| Total capacity |
512GB write once |
| Disc structure |
Guide Layer-separated
Structure 8-layer Double-sided |
| Data Bit Length |
87.39 mm |
| Track pitch |
0.32µm |
| Modulation method |
17PP |
| Error Corection method |
Reed-Solomon Code |
Optical parameters |
| |
Recording system |
Guide Optical system |
| Wavelength |
405nm |
650 nm |
| Numerical Aperture of an Objective Lens |
0.85 |
0.60 |
Media manufacturer Mitsubishi Kagaku Media Co., Ltd. has offered technical cooperation during the disc's development process, and the company is currently discussing the prospects market introduction of the new high-capacity disc.
Pioneer and Memory-Tech have also used this technology to successfully produce a prototype single-sided 10-layer sample disc. In addition, by repurposing existing signal processing technologies, the two companies have confirmed that double-sided capacities of up to 720 GB (36GB per layer) can be achieved without modification to recording devices. What’s more, by using new signal processing methods to increase the per-layer recording capacity and stack 12 or more layers (42GB per layer), the feasibility of capacities of 1TB or greater are being considered.
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