Philips Research, based in Redhill, has developed a low-temperature construction technique for active matrix LCDs (AMLCDs) that cuts power consumption.
Philips uses low-temperature polysilicon to integrate a dynamic memory bit into the display pixel, allowing eight colours to be displayed in standby mode. This reduces power consumption in standby to 1mW, opening up the possibility of using AMLCDs in smaller mobile devices.
Dr Koen Joosse, a spokesman for Philips Research, said: "With existing AMLCDs, transistors are usually made with amorphous silicon, but their quality is not good enough for driving electronics. The driving electronics is usually done with crystalline silicon on the circuit board. By using low-temperature polysilicon, you can realise higher levels of integration."
The team has achieved this integration with a laser-based local heating technique. A laser heats a specific point on the amorphous silicon surface. The heating converts the silicon to a crystal while leaving the glass and liquid crystal unaffected.
"By making it polycrystalline, the transistor qualities are enhanced," said Dr Joosse. "We have optimised the process to get good transfer qualities with mobility and a 1.2V threshold voltage.
"There is no problem with AMLCDs regarding image degradation, but work is needed to develop low-temperature applications. There is still some way to go to scale down transistor sizes to get high resolution. We are currently using 3µm design rules and would like to get down to 1µm."