Tokyo-Toshiba Corporation today announced innovations in the design and manufacture of low-temperature polysilicon thin film transistor (TFT) liquid crystal displays (LCD) that significantly boost pixel integration, enhance resolution, achieve a lower component count and reduce the size of external printed circuit board, all while achieving savings in power consumption and display cost.
Toshiba established its industry leadership in low-temperature polysilicon TFT LCDs by commercializing the world's first large sized displays, and since then has pioneered the development of ever-larger displays. The company today reconfirmed its cutting-edge position with a series of important innovations, including the integration of a digital-analog converter and amplifier into display peripheral circuits and the first application of 3-micron process technology to LCD manufacturing.
Toshiba's success in integrating the DAC and amplifier into the peripheral circuits marks a key industry-first that cuts the number of external components required for displays and the size of the PCBs housing those displays. The present DAC supports display of 260,000 colors, a level suitable for mobile information equipment.
The company's advance to 3-micron technology, at a time when other LCDs still rely on the 4-micron process, brings with it numerous advantages, starting with lighter, slimmer products. Circuit integration is boosted by approximately five times over current low temperature polysilicon LCDs, and the advanced level of process technology allows DAC and amplifier to be integrated on the glass substrate --a move that further cuts the peripheral component count and increases display efficiency. Integration of the DAC and amplifier analog circuits is achieved by advanced excimer laser anneal (ELA) technology that improves electron mobility to a level 50% higher than in current low temperature polysilicon LCDs, realizing a higher resolution. These advances in integration technology support the concept of "System on Glass," in which all external ICs are integrated on the glass substrate of the LCD, without any use of PCBs. In reflective LCDs each dot integrates a 1-bit SRAM, supporting lower power consumption during display of still pictures.
Toshiba recognizes the low-temperature polysilicon TFT LCD as offering the most promising solution for mobile personal equipment of any commercialized display. The displays are much lighter and slimmer than amorphous Si TFT displays, and their use of crystallized silicon results in a brighter, more responsive display offering higher resolution. The company currently deploys the widest lineup of low-temperature polysilicon TFT LCDs on the market, for application in cellular phones, personal digital assistants and portable PCs, and will enhance display performance though application of its new technologies.