Sony Blu-ray disc recorder to be presented soon - Printer Friendly version without Comments

Appeared on: Friday, May 2, 2003
Sony Blu-ray disc recorder to be presented soon

Sony Corp announced on April 10 its world's first recorder in compliance with the Blu-ray Disc optical disc protocol. Blue-ray Disc is expected to be the next-generation standard for discs to follow DVD. Sony announced on April 10 its world's first recorder in compliance with the Blu-ray Disc optical disc protocol. Blue-ray Disc is expected to be the next-generation standard for discs to follow DVD. In commercializing the BDZ-S77, Sony had been attempting to release it as soon as possible. From the start, the global electronic maker focused on development of recording capability of HDTV images of digital satellite broadcasting. It had given up development of some other capabilities because of some technical problems.Nonetheless, the BDZ-S77, the world's first Blu-ray Disc recorder, is equipped with many parts newly developed by Sony. At the same time, the new product adopts the same parts as used in current DVD models including an optical pickup for CDs and DVDs, to reduce development costs.

"With the BDZ-S77, you can record HDTV images on an optical disc, which is like a dream come true. I think the price of 450,000 yen is a real bargain," said Reiji Asakura, a digital media critic.

Sony had apparently been developing the new product for a long time with a view to releasing it this spring.

General Manager Yukinori Kawauchi, planning dept of AV/IT development group, said: "There has been a strong demand for such product from some consumers. We were thinking about announcing the new product as soon as details such as format and licensing of the logo are fixed.

In an attempt to realize an early release of the recorder, Sony decided to limit the new recorder's capabilities. One of the capabilities introduced by Sony is a recording of HDTV images of digital satellite broadcasting. Naturally as a consumer product, the recorder also has other basic capabilities of recording ground-based analog broadcasting, capturing image data taken by DV camera/VCR and replaying CDs and DVDs.

However, to realize such early release, Sony abandoned some other capabilities. For example, the new recorder is not capable of directly recording data streams including HDTV images from terrestial digital broadcasting to be launched in some areas of Tokyo, Nagoya and Osaka at the end of this year. A model to be equipped with a receiver module for such broadcast data will be commercialized this autumn, and Sony could not wait until then.

The BDZ-S77 also supports limited types of media. Although the recorder is compatible with the already planned rewritable disc standard BD-RE, Sony says it will be difficult for the company to make the recorder capable of recording and replaying replay-only-disc BD-ROM and recordable optical disc BD-R (two tentative names).

Sony is developing an official model to be compatible with BD-ROM and BD-R with a view to releasing it by the end of the year. However, it says, as things are now, the compatibilities with the both media will be fairly difficult to realize.

For example, to realize the compatibility with BD-ROM, Sony plans to add the differential phase detection (DPD) method to the current tracking method. As for the compatibility with BD-R, there may be a significant change in write strategy, multi-pulse modulation to be input in semiconductor laser upon recording. To respond to these changes, the new recorder will likely need to replace its optical pickup and LSI chips with new ones.

Sony also gave up the compatibility with a two-layer rewritable disc. Two-layer rewritable disc switches its layer by moving an objective lens and changing a recording layer on which a focus is made. However, the maker did not introduce the mechanism in the new recorder.

Despite the limited capabilities, the BDZ0-S77 is fully equipped with new parts. For example, the firm developed an optical pickup, the nucleus of the product, with the light source of a blue-violet semiconductor laser. It measures 80mm x 47mm x 31.6mm. Nichia Corp developed the light source.

The rated optical power for continuous oscillation is 30mW. The company developed the pattern of outgoing laser beams that is almost a circular form, using an anamorphic prism. It adopts the double objective lens with the numerical aperture of 0.85, as well as an uniaxial actuator to correct the spherical aberration caused by the uneven thickness of the cover. It has an optical pickup compatible with both CDs and DVDs to replay both types of discs, in addition to an optical pickup for Blu-ray Discs.

The two pickups are located facing each other across a spindle motor. The optical pickup for CD/DVD is the same one as used in the current DVD models.

Additionally, Sony developed some semiconductor chips to be used in the front-end circuit, a part related to recording and replaying of discs. It uses different chips for different functional blocks.

Such newly developed semiconductor chips include a chip to drive a semiconductor laser, a chip to control the semiconductor laser, an RF amplifier chip, a chip to detect address information, and a chip to generate pulse modulation of write strategy. The company also developed a circuit, called 1-7PP, to process record encoding and decryption and correct errors, all integrated on a single chip.

A mechanism to cushion the shock on the optical pickup is also incorporated. Such a mechanism is designed to avoid a collision of the disc and the objective lens and any deviances in tracking. Furthermore, the disc is protected from a possible collision with the objective lens. Sony used resin to fix two lenses and tried to make an optical lens collide with the resin first, instead of with the disc, when a shock occurs. Although the resin supports the lenses, its degree of hardness is low so that it won't hurt the disc.

Sony also took the image quality into great consideration. Assuming that most users who will purchase the new recorder have a HDTV receiver, the maker developed a LSI chip to reduce noise from HDTV images and an interlace/progressive conversion LSI chip that can detect any movements more accurately. It developed a total of six new LSI chips including the above-mentioned two for backend circuits, where AV and other data are processed.