NEC's Panel-Sized Scan Driver is World's First System-on-Glass Driver LSI Chip to Achieve 768 Outputs for XGA TFT-LCDs

NEC's Panel-Sized Scan Driver is World's First System-on-Glass Driver LSI Chip to Achieve 768 Outputs for XGA TFT-LCDs

SAN FRANCISCO, Feb. 8 /PRNewswire-FirstCall/ -- NEC Corporation (NASDAQ:NIPNY) (FTSE: 6701q.l) today announced the development of a panel- sized scan driver, the world's first system-on-glass (SOG), large-scale integrated (LSI) chip to achieve 768 outputs for extended graphics array, thin-film transistor, liquid crystal displays (XGA TFT LCDs). The new driver is expected to realize lower manufacturing costs and smaller module volume for medium to large TFT-LCDs. Results of this research will be presented at the International Solid-State Circuit Conference (ISSCC) 2005 in San Francisco being held February 7 through 9.

Panel-sized drivers possess a length approximate to that of LCD width or height, have identical outputs for scan and column lines, and do not require tape-carrier packages (TCPs) or printed circuit boards (PCBs) in assembly. The drivers are silicon-on-insulator (SOI) devices made on a glass substrate with a complementary metal-oxide-semiconductor (CMOS) TFT circuit. Taking into account the floating-body effect, NEC has successfully fabricated a 189-mm- long scan driver with 768 outputs for XGA TFT LCDs using NEC's own low-voltage (5V) and high-voltage (15V, 40V) CMOS TFTs.

The features of the prototype panel-sized scan driver are as follows:
(1) With a length of 189 millimeters (mm) and a width of 1.41 mm, the
driver is narrow enough to be assembled at the edge of an LCD.
(2) Although conventional modules need to be assembled with more than 10
parts, panel-sized driver modules only require that the drivers be
assembled directly on the LCD panel. In addition, they do not require
PCBs or TCPs. As a result, the assembly time for panel-sized drivers
is significantly accelerated, as there are only three parts to
assemble.
(3) Due to a new level-shifter circuit, which greatly reduces unexpected
delays caused by the floating-body effect of TFTs, stable operations
can be achieved in wide duty/voltage ranges.



Panel-sized drivers are fabricated on a large, rectangular, glass substrate with SOG technology and possess identical thermal expansion coefficient to LCD glasses. They also contain functions for TCPs and PCBs. As a result, SOG panel-sized drivers can be fabricated at a reasonable cost with superior assembly reliability.

"The development of the world's first prototype of panel-size scan driver is a great breakthrough for the semiconductor industry. We expect it will contribute significantly to the lowering of manufacturing costs for TFT LCDs, enabling thinner modules, and thus eventually decreasing the price of laptop computers and portable terminals with TFT LCDs," said Dr. Masao Fukuma, vice president, R&D Unit, NEC Corporation.

SOG TFT LCDs, in which poly-silicon (p-Si) driver circuits are monolithically integrated on LCD panels, are often used for mobile phones and other applications because they do not need driver LSI assembly and have small module volumes. As LCD size increases, the proportion of the driver circuit area in a whole display panel decreases rapidly. It is well known that p-Si TFT fabrication processes are more expensive than those of amorphous-silicon (a-Si) TFTs. As expected costs for existing SOG LCDs do not seem to match market prices, a-Si TFT-LCDs assembled with LSI drivers are currently widely used for medium to large LCDs. However, there is still strong demand for small-module volumes in portable-terminal applications such as laptop personal computers.

NEC will continue to carry out aggressive research activities toward commercialization of its panel-sized scan drivers.

*Note: (1) Floating-body effect: Refers to the drastic change in a transistor's body potential depending on dynamic bias conditions. This effect often causes unexpected hysteresis characters.

About NEC Corporation

NEC Corporation is one of the world's leading providers of Internet, broadband network and enterprise business solutions dedicated to meeting the specialized needs of its diverse and global base of customers. Ranked as one of the world's top patent-producing companies, NEC delivers tailored solutions in the key fields of computer, networking and electron devices, by integrating its technical strengths in IT and Networks, and by providing advanced semiconductor solutions through NEC Electronics Corporation. The NEC Group employs more than 140,000 people worldwide and had net sales of 4,906 billion yen (approx. $47 billion) in the fiscal year ended March 2004. For additional information, please visit the NEC home page at http://www.nec.com/.


Source: NEC Corporation

CONTACT: In Japan: Diane Foley of NEC Corporation, + 81-3-3798-6511 or
d-foley@ax.jp.nec.com; In the Americas: Denise Viereck Garibaldi of NEC
Electronics America, Inc., +1-408-588-6620 or denise_garibaldi@necelam.com; or
In the Americas: Kazuko Andersen of NEC USA, Inc., +1-212-326-2502 or
kazuko.andersen@necusa.com

Web site: http://www.necel.com/


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