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SEOUL, SOUTH KOREA, MAY 10, 2000 - LG.Philips LCD Co., Ltd. ,one of the world`s largest innovators of liquid crystal display (LCD) technology, today announced that the company is taking a giant step toward picture-perfect mobile displays with its proprietary low-temperature poly-silicon (LTPS) process technology for TFT-LCDs. The production technology creates thin, lightweight displays with exceptional brightness and resolution capabilities.
LG.Philips LCD was the first Korean company to develop high resolution LTPS technology. This year, the company transferred the technology from its Anyang-based research lab to its factory in Kumi, Korea. Engineers in Kumi have now begun volume production of a 10.4-inch commercial product.
Beginning in the second half of year 2000, APC (American Panel Corporation), a leading American avionics display company based in Alpharetta, GA., will integrate the LG.Philips LCD device in avionics navigational instrumentation. In such applications, the display must be shock resistant, bright and stable over a wide temperature range. Manufacturing experience and further cost reductions are expected to put the high-resolution technology within reach of consumer electronic product companies in the near future. IMT-2000 telecommunication products, personal digital assistants (PDAs), electronic picture frames and other new applications can all benefit from the lightweight and reliable displays made possible by this breakthrough technology.
This commercial introduction makes LG.Philips LCD only the second company to offer large, high resolution displays of this type. The 10.4-inch (diagonal)XGA screen delivers 1.6 times more pixels than conventional displays of that size. Other companies making small LTPS displays use complex complimentary metal-oxide semiconductor (CMOS) devices that require up to twice the lithographic process steps of conventional TFT-LCDs. The proprietary positive-channel, metal-oxide semiconductor (PMOS) technology developed by LG.Philips LCD requires only 70 percent of the processing needed for CMOS devices. Until now, LTPS displays had attractive features but were out of reach in their production lists for many applications. The company`s new process advantage should also hasten the delivery of brighter, finer displays for notebook and desktop usage to support e-commerce and entertainment applications.

Technology Backgrounder
In conventional active-matrix LCD designs, thin-film transistors are formed from amorphous silicon (a-Si). The fabricated transistors act as switches for each picture element (pixel). High resolution displays can require one million or more transistors for the pixel array. In addition, other circuits that convert computer signals into the format appropriate for display must control the pixel switches. Unfortunately, amorphous silicon films create relatively slow transistors. As pixel sizes are reduced to provide higher resolution, the pixel switch comes to occupy a larger portion of the display area. Amorphous silicon transistor size and performance therefore limits the number of pixels that can be illuminated per square inch. In addition, conventional transistors cannot be used to drive (control) these pixel switches. Manufacturers must attach custom integrated circuits (IC) packages to the panel for driving and scanning functions.

Poly-silicon films can form much faster and smaller transistors. Circuit performance is close to that of typical ICs built on silicon wafers. Direct-view TFT-LCD devices must be fabricated on glass sheets instead of wafers, so lower temperature processes have been developed. The resulting low-temperature, poly-silicon transistors permit much tighter spacing of pixel switches without reducing display brightness. The more robust devices also allow control circuitry to be fabricated on the glass, thus reducing the number of external components and connections. Off-panel connections have proved to be the most frequent cause of LCD failure, so LTPS-based products promise to be more reliable in mobile applications.

Unfortunately, the LTPS fabrication techniques currently employed by other manufacturers require about twice as many steps as a-Si. The reduction of external component cost has been offset by the higher fabrication cost in many commercial applications, resulting in higher display prices. LTPS devices have therefore been offered only in premium products or in applications requiring very small pixels, such as digital cameras. LG.Philips LCD`s breakthrough process reduces the cost offset, thereby making high performance displays possible in a wider variety of products.