Pioneer Corp. said on Monday that it had succeeded in developing a 16-layer read-only optical disc with a capacity of 400GB for the first time in the world. According to Pioneer, the discs manufactured using the same methods as those utilized to create the 400GB media may be used to create Blu-ray discs with similar capacities compatible with Blu-ray optical drives.

For multilayer optical discs, it has been difficult to obtain clear signals from each recording layer in a stable manner due to crosstalk from adjacent layers and transmission loss. Utilizing the optical disc production technology that it has developed in the DVD field, Pioneer solved these problems by, among other things, using a disc structure that can reduce crosstalk from adjacent layers, resulting in a 16-layer optical disc that can playback high-quality signals from every layer.

As for the read-out system, Pioneer achieved stability in the playback of recorded signals by employing a wide-range spherical aberration compensator and light-receiving element that can read out weak signals at a high signal-to-noise ratio in the optical pick-up mechanism. Since the optical specifications of the objective lens, such as numerical aperture (the higher numerical aperture of the objective lens, the smaller diameter of the beam spot focused on a disc surface), are the same as those for the existing BD discs, it is possible to maintain compatibility between the new 16-layer optical disc and the BD discs.

The 16-layer optical disc technology, capable of storing much more data than the conventional discs on one disc, will greatly reduce the number of discs to be used and therefore contribute to the conservation of resources.

Pioneer will present the details of this research at the International Symposium on Optical Memory and Optical Data Storage 2008 (ISOM/ODS2008) to be held in Hawaii from July 13.