Laser annealing

A UK company claims it has developed a more cost-effective technique for manufacturing flat screen displays that use less energy than conventional screens.

of Crawley, West Sussex has developed a powerful environmentally-friendly laser for producing active matrix organic light-emitting diode (AMOLED) screens.

These screens match the picture quality of their plasma equivalents but use much less energy. Until now their manufacturing technique has made them too expensive for most consumers.

Mike Mason, vice-president of technology at Powerlase, said the difference between an organic light- emitting diode (OLED) display and an AMOLED display is that each pixel in an AMOLED screen uses a number of small transistors — located next to each pixel within the display — to turn it on and off.

'To produce a good performance display with fast response time, the transistors must be made with high-quality silicon crystals,' said Mason.

Normally, silicon is coated on to the screen in a non-crystalline layer during the manufacturing process. To turn this into crystalline silicon it needs to be treated with a laser annealing process, which heats up the silicon then allows it to slowly cool to grow silicon crystals.