Pocket-sized projector offers big-screen action

 作者:海瑜     |      日期:2019-03-03 01:06:00
By Barry Fox Impromptu movie screenings and executive PowerPoint presentations will soon be possible thanks to a pocket-sized portable projector developed by Toshiba. The battery-powered device is small enough to be slipped into a handbag and can be plugged into a laptop computer or mobile phone. Whereas existing projectors use a bright white lamp and a rapidly rotating wheel with red, green and blue filters to generate a projected picture, Toshiba’s new system uses red, green and blue light-emitting diodes (LEDs) instead. And since the LEDs generate very little waste heat there is no need for a bulky cooling fan, which means the unit can be made small and light – its dimensions are just 136 millimetres x 39 mm x 100 mm. LEDs also last for thousands of hours and can be turned on and off quickly, while conventional projector lamps take a while to warm-up and cool-down. The Toshiba projector was unveiled by the Japanese company this week at the IFA consumer electronics show in Berlin, Germany. At the same event, Epson also revealed a compact LED projector prototype, while Mitsubishi, another Japanese company, has already demonstrated its own version. But the Toshiba model will be the first of its kind to go on sale before the end of 2005, and will cost about €1000 ($1250). The launch of the Toshiba projector could signal a new trend in portable video, says James Stewart, a technology researcher at the University of Edinburgh in Scotland. “I think they have a good future,” he says. Stewart says the device will appeal to people who want a portable way to view a large version of a cellphone display or handheld-computer screen. He notes that LED light sources are not as powerful as regular bulbs, but acknowledges this problem is being addressed. “And for close-range projectors and domestic use, brightness is not so much of a problem,