PS3: Inside the Optical Head

Nikkei Electronics finished tearing down the "PlayStation 3" (PS3), but could not cover full details as we tore it down and posted reports on the same day as soon as it was released. We therefore consider reporting further details when we can later on.

We would like to pick up the Blu-ray Disc (BD) drive first, which should be regarded as one of the PS3's core modules.

One Objective Lens, One Laser Unit

In this BD drive, different system objective lenses are packed into one. The PS3 also uses a semiconductor laser dubbed "three-wavelength laser," a package, which can radiate near-infrared laser for CD, red laser for DVD and blue violet laser for BD.

Many other consumer products have used an optical unit combining an objective lens and a laser device for BD, separately from the other unit for CD and DVD. This was because, despite the larger number of components, this method allows diverted use of existing low-price CD/DVD components, as well as most simple combination of BD components, whose individual technologies are too new to constantly generate high quality products.

Of course, there is no doubt an integrated optical system will be more advantageous if component and manufacturing technologies are improved. It will allow not only size reduction but also better efficiency in volume production and cost (related story on Tech-On! "Kutaragi Talks about BD-ROM Employment for Next-Generation PS"). Nevertheless, only few manufacturers can actually start development and volume production of such an integrated optical system. That is because both technological hurdles that must be overcome before commercialization and development cost are too high. To withstand such a heavy burden and generate profit, the manufacturer needs at least to have a clear prospect for long-term, sustainable shipments of a considerable amount of the optical head it develops.

In fact, Sony Computer Entertainment Inc. (SCE) did the same thing when releasing the "PlayStation 2," which supports DVD-ROM discs. The company developed and employed the "two-wavelength laser" that integrates optical heads for CD and DVD, which had been provided separately by most other manufacturers before then.

SCE once again integrated different optical systems into a single head. This time, however, must have required technology that is incomparably higher than last time. SCE seems to have insisted on the integration for future cost reduction, as well as reduction in size and thickness of an optical head that fits inside the PS3. Meanwhile, given the same distance of 0.6 mm between the signal layer and disc surface, it is not difficult to integrate HD DVD, BD's rival format, and CD/DVD optical systems. SCE may intend to be comparable in this respect as well.

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