Semiconductor Energy Laboratory Co Ltd (SEL) and Advanced Film Device Inc (AFD) announced an oxide TFT LCD panel that can drastically reduce the power consumption required to display still images at SID 2010 (thesis number: 43.4).
The panel can keep displaying a still image stably for one minute without any writing action by lowering the frame frequency to 1/60Hz. In theory, it is possible to lower the power consumption required to drive the panel to 1/3,600, compared with the power consumption at a frame frequency of 60Hz.
This time, SEL and AFD developed a drive circuit that can lower the frame frequency when a still image is displayed and formed the circuit on a glass substrate by using an IGZO (In, Zn, Ga, O) oxide semiconductor TFT with a high mobility.
Furthermore, they restrained the increase in power consumption caused by leak current by newly developing a normally-off type oxide semiconductor TFT, in which current does not flow when the applied voltage is 0V. But they did not reveal how they realized the normally-off type oxide semiconductor TFT.
SEL and AFD prototyped an oxide TFT LCD panel based on the new technology and showed it at SID 2010. It has a screen diagonal of 6 inches, a pixel count of 1,024 x 768 (XGA), a resolution of 212ppi and an aperture ratio of 54%.