Liquid crystal display device and driving method thereof

Abstract

A reflective region where display is performed with reflection of incident light through a liquid crystal layer and a transmissive region where display is performed by transmission of light from a backlight are provided, and the reflective mode and the transmissive mode are switched. In the case of displaying a full-color image, a pixel portion includes at least a first region and a second region, a plurality of lights of different hues are sequentially supplied to the first region according to a first order, and a plurality of lights of different hues are also sequentially supplied to the second region according to a second order which is different from the first order. In the transmissive mode, the reflective region is made to display black, so that decrease in contrast due to reflection of external light at the reflective region is prevented.

1 . (canceled) 
     
     
         2 . A display device comprising:
 a pixel portion comprising a pixel comprising:
 a first transistor and a second transistor electrically connected to each other in series; 
 a first pixel electrode electrically connected to a signal line through the first transistor but not through the second transistor; and 
 a second pixel electrode electrically connected to the signal line through the first transistor and the second transistor, 
   wherein a gate of the first transistor is electrically connected to a scan line,   wherein a gate of the second transistor is electrically connected to an enable line, and   wherein each of the first transistor and the second transistor comprises an oxide semiconductor layer comprising indium, gallium, zinc, and oxygen.   
     
     
         3 . The display device according to  claim 2 , wherein the first pixel electrode is transparent. 
     
     
         4 . The display device according to  claim 2 , wherein the second pixel electrode is reflective. 
     
     
         5 . The display device according to  claim 2 , wherein the enable line is provided across the scan line. 
     
     
         6 . The display device according to  claim 2 , wherein the enable line is provided in a layer different from the scan line. 
     
     
         7 . The display device according to  claim 2 , comprising a liquid crystal layer over the first pixel electrode and the second pixel electrode. 
     
     
         8 . The display device according to  claim 7 , comprising a counter electrode over the liquid crystal layer. 
     
     
         9 . The display device according to  claim 2 , wherein the first pixel electrode and the second pixel electrode are provided on and in contact with a same surface. 
     
     
         10 . A display device comprising:
 a pixel portion comprising a first pixel in a first row and a second pixel in a second row that is different from the first row, each of the first pixel and the second pixel comprising:
 a first transistor and a second transistor electrically connected to each other in series; 
 a first pixel electrode electrically connected to a signal line through the first transistor but not through the second transistor; and 
 a second pixel electrode electrically connected to the signal line through the first transistor and the second transistor, 
   wherein a gate of the first transistor in the first pixel is electrically connected to a first scan line,   wherein a gate of the first transistor in the second pixel is electrically connected to a second scan line,   wherein a gate of the second transistor in the first pixel is electrically connected to a gate of the second transistor in the second pixel through an enable line, and   wherein each of the first transistor and the second transistor in each of the first pixel and the second pixel comprises an oxide semiconductor layer comprising indium, gallium, zinc, and oxygen.   
     
     
         11 . The display device according to  claim 10 , wherein the first pixel electrode is transparent. 
     
     
         12 . The display device according to  claim 10 , wherein the second pixel electrode is reflective. 
     
     
         13 . The display device according to  claim 10 , wherein the enable line is provided across the first scan line and the second scan line. 
     
     
         14 . The display device according to  claim 10 , wherein the enable line is provided in a layer different from the first scan line and the second scan line. 
     
     
         15 . The display device according to  claim 10 , comprising a liquid crystal layer over the first pixel electrode and the second pixel electrode. 
     
     
         16 . The display device according to  claim 15 , comprising a counter electrode over the liquid crystal layer. 
     
     
         17 . The display device according to  claim 10 , wherein the first pixel electrode and the second pixel electrode are provided on and in contact with a same surface.