Site: Sony Corporation
(optical storage presentations)
Research and Development Center
6-7-35 Kitashinagawa, Shinagawa-ku
Tokyo 141-0001, Japan
http://www.sony.co.jp/

Date Visited: 10 March 1998

WTEC:

• M. Keshner (report author)
• S. Esener
• K. Rochford

Hosts:

• Mr. Masahiko Kaneko, Mgr. Adv. Development Lab
• Dr. Shigeo Kubota, General Mgr. and Chief Scientist, Research Center

BACKGROUND

Sony is an electronics and entertainment company with more than $46 billion in sales. Roughly 78% of the sales are from electronics, and 22% are from movies and music. In the electronics business, about 14% are VCRs, 18% are audio products, 18% are television sets, and 27% are other. Movie production accounts for 10% of sales, and music, 8%. For the year ending in April of 1997, Sony had a profit of $3 billion and spent about $2 billion on R&D. One-third of the $2 billion was spent on advanced R&D and two-thirds were spent on product design. The Corporate Research Center has several divisions:

• Research Center-devices and materials
• Advanced Development-optical disk, magnetic recording and new concepts
• Media Processing
• Information Technology
• Advanced Production
• Next Century-development of the "robot pet"
• Platform Software Development

The Sony Corporation has 163,000 employees worldwide and is divided into several companies:

• Displays
• Home Audio Visual
• Personal Audio Visual
• Information Technology (PCs)
• Personal & Mobile (auto products and cellular phones)
• Broadcast and Professional
• Digital Network Solutions
• Semiconductor
• Computer Peripherals
• Recording Media and Energy

DISCUSSION

The entire WTEC team attended an overview presentation of the Sony Corporation and the Sony Research and Development Center. Then the group was split for presentations on magnetic recording and on optical recording. (See previous Sony site report in this appendix, for magnetic storage discussions.)

Mr. Kaneko from the Optical Media Lab, within the Advanced Development Lab, presented Sony's ideas for high capacity. He presented ideas for extending both phase change and magneto optic technologies to achieve 15-20 Gb/in² or about 20-30 GB on a DVD disk. They included the following:

1. Phase change recording, using a thin substrate (0.1 mm ±3 µm), a high NA lens (0.85), Using a PR (121) ML read channel, a (1,7) code and land & groove recording, with a 635 nm laser, they showed excellent eye patterns at 8 GB per disk. With a 515 nm laser, they could achieve 12 GB per disk. Writing power was 5 mW at 3.4 meters per second. With 2-4 layers, and a 410 nm laser, capacities of 35-70 GB are possible.
2. Magneto optic recording, using a 650 nm laser, NA=0.6 and land & groove recording, with an NRZI code, a CAD disk to reduce crosstalk and magnetic field modulation. Readout requires a super-resolution technique, either magnetic amplifying magneto-optical system (MAMMOS) from Hitachi-Maxell or domain wall displacement detection (DWDD) from Canon.

Sony managers also presented their ideas for a very high capacity ROM optical disk. The technology is called "single carrier independent pit edge recording" (SCIPER). It is designed for a blue laser (410 nm) and uses the following ideas:

• SCIPER stores data by modulating the position of the leading and trailing pit edges in very small discrete steps. Mark centers are precisely every 0.38 µm. The mark size to the left of the bit center varies to encode 4 bits (16 sizes), with a maximum of 0.16 µm in steps of 0.01 µm. The mark size to the right encodes another 4 bits.
• SCIPER will be combined with radial direction partial response (RPR) encoding, where data are read out simultaneously from two adjacent tracks. The crosstalk between two adjacent tracks is removed by pre-coding. Track pitch is 1/2 roughly 0.45 microns. Hence, the optical spot always sees two tracks at once. The signal from the first track is read separately. Then, for all subsequent tracks, one of the track signals is subtracted from the combined signal. The use of a 2D code is envisioned to minimize crosstalk between tracks that are read simultaneously.
• Using SCIPER together with RPR to improve the track density can extend the areal density up to 100 Gb/in² or about 150 GB per disk. Please note that this is a ROM technology. Excellent signal-to- noise ratios will be required. The key will be extremely precise mastering technology with better than 7 nm resolution.

In the final presentation, Dr. Kubota discussed Sony's advanced mastering technology. It uses quadrupling of a YAG laser to achieve a wavelength of 266 nm. The non-linear crystal is a Czochralski grown beta barium borate. The cutoff wavelength is about 193 nm. Scattering at 213 nm is less than 2%. The power in the green laser is 0.45 watts and the output power at 266 nm is about 100 mW. Lifetime is more than 1,000 hours at this power in a shoe box sized device.

SUMMARY

Sony has made major investments in optical disk recording, both erasable and read only. The company is not publicly committed, as yet, to either phase change or magneto-optic technology for its product roadmap. Managers feel that both technologies can lead to products in the 15-30 GB range. They have shown the feasibility for a ROM product with over 100 GB capacity per disk.