Power efficiency - Page 4

There's a new report by the Cleantech Group that says that e-readers are green. In fact, according to the projected sales of e-readers in 2009 and 2012 could reduce co-2 emissions by 10.9 million tons.

Their analysis says that one year of use could offset the emissions made by manufacturing and distribution (and operation). Each following year of use could actually be preventing the release of 370 pounds of carbon dioxide per user (assuming individuals buy about 22.5 books a year).

The report mentions that using an e-paper based reader (currently almost all of these are E Ink based) is best - because of the low power consumption.

Samsung are showing a 10.2" hybrid LCD/epaper display that's capable of color video. This is somewhat like Pixel-Qi's hybrid display - it can switch between regular LCD and a 'memory' mode in which only changes in display draw power.

Samsung Hybrid LCD-ePaper

Cuttlefish are able to change their skin color quickly. Now scientists from MIT are working to create displays that are extremely efficient - using less than one-hundredth the power of today's TVs.

Cuttlefish use chemicals to change the space between membranes on their skin. The researchers have created an artificial electrical system that controls spacing between layers in their display, thus changing the color.

The prototype display is several inches across, and only one micron thick - inside there are around 20 layers of polystrene and responsive poly-2 vinyl. The poly-2 vinyl expands as the voltage increases, becoming thicker, and reflecting longer wavelengths of light. Without electricity it is clear.

The screen can also reflect non-visible wavelengths of light, such as infrared and ultraviolet, depending on the voltage applied. It can produce images using only a few volts because it doesn't create light, it only reflects it. In a dark room with no light, the screen would remain dark.

The researchers also say that the screen is very easy to make, but have a limited viewing angle.