NEC Corporation

Research and Development

During fiscal 1996, NEC succeeded in developing an optical disk recorder that can repeatedly record and play back video data on both sides of a 120-mm-diameter high-performance optical disk. With a total of 10.4Gbytes of memory, this double-sided disk has roughly 16 times the capacity of a standard CD-ROM. Conforming to the MPEG2 international standard, it provides up to four hours of playback memory. In addition, when combined with a codec for recording, it can record up to 40 minutes worth of conventional broadcast-quality pictures in digital form. The compact size of this breakthrough system makes it ideal for business and studio applications.

NEC's R&D activities are focused on the basic themes of developing new technologies that can generate new business, speeding up multimedia technology development, and finding more-effective solutions to environmental problems. In fiscal 1996, we concentrated our R&D efforts on multimedia internetworking, super parallel processing and related software, information agents, multimedia filing systems, and technologies for 0.1-micron level silicon ultra-large-scale integrated circuits (ULSIs).

In software engineering, progress was made in the development of microcomputer software, client-server software technologies, and networking technologies as well as in the upgrading of software development processes. As for production technology, the period under review saw achievements in such areas as manufacturing processes and mass-production lines, production information system technologies, plastic materials applications, and assembly technologies aimed at improving recycling and energy efficiency.

Against the background of an increasingly information-oriented society and accelerating multimedia development worldwide, in fiscal 1996 NEC strengthened its global multimedia research structure. We established a multimedia software research facility in California, the United States, and a multimedia communications research facility in Berlin, Germany.

R&D Highlights

Semiconductor Laser Diode for Produc-ing Light of Varying Wavelengths

In the wavelength division multiplex (WDM) optical transmission system, signals with varying wavelengths are transmitted simultaneously through the same optical fiber, thus enabling the transmission of a greater volume of information. NEC has developed a semiconductor laser diode capable of producing light of varying wavelengths that is suitable as a signal source for WDM optical transmission systems. Employing a new stair waveguide route structure, the diode is able to gradually vary the transmission wavelength in accordance with the thickness of the waveguide route. Whereas previous methods required the fine adjustment of two control currents, the development of this diode has enabled the simple adjustment of wavelength using just one control terminal.

Power Transistor which Requires Low Supply Voltage

NEC has developed a highly efficient power transistor that draws sufficient power to operate a cellular phone from a supply voltage equivalent to that provided by a 1.2V nickel-hydrogen battery. The power transistors in cellular phones are the biggest drains on batteries, so a power transistor that can operate on such a low voltage is indeed a significant development. Based on a heterojunction field effect transistor (FET), which can operate efficiently on a low supply voltage, NEC's new transistor incorporates a double-doped heterojunction in which the channel is sandwiched between carrier supply layers.

PrivateNet-An Internet Security System

During fiscal 1996, NEC launched PrivateNet, an Internet security system. Based on the architecture of network management proxy servers, the system encodes transmissions to tightly restrict access from outside through the Internet. The existence of the firewall is not apparent to internal users, and the instructions that appear on screen make the system simple to install and enable easy operation and management by nonspecialist personnel.

Multi-Chip Module (MCM) Mounting Technology

NEC has developed a highly reliable, low-cost MCM technology for the direct mounting of bare LSIs onto a fine printed wiring board, a technology that is essential to realizing future portable electronic products. NEC has developed a gold ball-bump technology, which can be manufactured using existing equipment, thus minimizing investment costs. Furthermore, NEC has developed a method of fixing LSIs to a board using lead-free solder, without flux. Conventional methods of soldering LSIs to boards require the use of lead-tin solder and flux. After soldering, the flux has to be washed off, which can cause corrosion to the soldered area. With NEC's method, however, the join between the LSI and the board is more reliable. Moreover, the new method is more environment friendly as it does not use lead.

NEC has developed a unified VOD groupware system that uses an ATM network to bring together multimedia groupware with VOD capability. Dubbed VOD Plus ATM MERMAID, the system enables multiple users in different places to simultaneously engage in meetings and conduct group work by sharing access to multimedia data for cooperative processing and playback.

The Silicon View Player is a high-performance portable video player. With a memory card as its storage medium, it features the picture quality of a household video cassette recorder (VCR) and the sound quality of a CD player. The player's compact size and light weight were achieved by incorporating a newly developed MPEG1 audio-video single-chip decoder, thus eliminating such mechanical parts as motors.

In collaboration with Moli Energy (1990) Limited, of Canada, NEC developed the first battery to use low-cost lithium manganate as an electrode material. This small, light-weight lithium-ion battery features large capacity and can be recharged repeatedly, making it suitable for use with mobile communications terminals. Full-scale production began at Nippon Moli Energy Corporation in April 1996.

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