By using an oxide semiconductor, we successfully prototyped a 3.4-inch QHD LCD panel including data and scan drivers; their power consumption is reduced by variable frame frequency (from 1/60 fps to 120 fps) depending on images. Low frame frequency in displaying still images on a PC monitor can reduce eyestrain.

We devised a 5Tr+1C threshold voltage compensation pixel circuit that operates even with a normally-on transistor. Variations in threshold voltage can be reduced to 25 to 30%. We fabricated a 13.5-inch quad full high definition (QFHD) OLED display, which has a top-emission structure using white tandem OLEDs with color filters.

We prototyped a 6.0-in. color sequential XGA LCD using an oxide semiconductor. A color sequential LCD has lower power consumption than a color filter LCD because light use efficiency is better. We utilize the low I off of the oxide semiconductor and make frame rate lower, which leads to the lower power consumption of drivers. The color sequential LCD can have a monochrome electronic paper function with a white backlight on.

No abstract

An oxide semiconductor thin film transistor (TFT) has much higher mobility than an amorphous silicon (a-Si) TFT, which leads to realization of larger displays with higher definition. Moreover, it has much lower off leak current than the a-Si TFT. We have focused on this feature and successfully fabricated a low-power 6.0-inch extended graphics array (XGA) transmissive liquid crystal display (LCD) with source and scan drivers integrated on a glass substrate. In order to realize low power consumption, unnecessary rewriting is not performed at the time of still image display. The interval between rewrite operations in our panel could be extended to about 1 min (= 1/60 fps) at the time of displaying still images. The power consumption of the drivers at 1/60 fps can be about 1/3,600 of that at 60 fps. We also discuss burn-in and flickers, which might be observed when this driving method is applied.