Epson has developed what is believed to be the world's first fully operational flexible 8-bit asynchronous microprocessor using low-temperature polysilicon thin-film transistors (LTPS-TFTs) on a plastic substrate. With energy consumption reduced by 70% compared to the synchronous microprocessors now in everyday use, Epson is now examining potential applications for its invention. The results of this research were announced at ISSCC2005, the International Solid-State Circuit Conference, held in February in San Francisco, USA.
The combination of Epson's original SUFTLA (Surface Free Technology by Laser Ablation /Annealing) technology, LTPS-TFTs technology, and asynchronous circuit design technology has made it possible for the company to create stable displays that are large in size, and that use substrates that are both flexible and variable in shape. SUFTLA is an Epson developed technique that makes it possible to transfer LTPS-TFT circuits onto flexible substrates.
Using the asynchronous circuit design technology, Epson has been able to:- make a stable 8-bit microprocessor composed of 32,000 LTPS-TFTs; achieve energy consumption 70% lower than the synchronous design and; reduce electromagnetic radiation by 20dB. The company believes this is the first time that a fully operational 8-bit asynchronous microprocessor has been placed onto a flexible substrate.
Epson is of the opinion that technologies based on flexible circuitry will be of critical importance, as society becomes ever more familiar with ubiquitous computing and mobile devices.
Epson's future R&D into asynchronous microprocessors will concentrate on establishing this technology on a practical level, as well as searching for potential applications. The Epson flexible circuit comprises 32,000 transistors (LTPS TFT with a gate length of 4 m. It is compatible with the Epson original S1C88 8-bit microcomputer series. External dimensions are 27 x 24 mm, with a thickness of 200 mand a weight of 140 mg. The operating voltage range of is 3.5 V to 7 V, and maximum frequency 500 KHz at 5V with a current consumption of 180 µA.
Epson Europe GmbH, 80992 Munich, Germany