Display device and driving method thereof

Abstract

It is an object of the present invention to provide a display device in which problems such as an increase of power consumption and increase of a load of when light is emitted are reduced by using a method for realizing pseudo impulsive driving by inserting an dark image, and a driving method thereof. A display device which displays a gray scale by dividing one frame period into a plurality of subframe periods, where one frame period is divided into at least a first subframe period and a second subframe period; and when luminance in the first subframe period to display the maximum gray scale is Lmax1 and luminance in the second subframe period to display the maximum gray scale is Lmax2, (1/2) Lmax2<Lmax1<(9/10) Lmax2 is satisfied in the one frame period, is provided.

1 . (canceled) 
     
     
         2 . A display device comprising:
 a first wiring and a second wiring extending in a first direction;   a third wiring extending in a second direction intersecting the first direction;   a first transistor; and   a pixel electrode over the first transistor,   wherein the first transistor comprises:
 a gate electrode over a substrate; 
 a gate insulating layer over the gate electrode; 
 a semiconductor layer on the gate insulating layer; 
 a source electrode over and in contact with a first region of the semiconductor layer; and 
 a drain electrode over and in contact with a second region of the semiconductor layer, 
   wherein the semiconductor layer comprises a third region being thinner than each of the first region and the second region of the semiconductor layer,   wherein the first wiring comprises a first region configured to be the gate electrode of the first transistor,   wherein the second wiring comprises a first region overlapped with the pixel electrode,   wherein the third wiring comprises a U-shaped region configured to be the source electrode of the first transistor, and   wherein the pixel electrode is electrically connected to the drain electrode.   
     
     
         3 . The display device according to  claim 2 , wherein the semiconductor layer comprises amorphous silicon. 
     
     
         4 . The display device according to  claim 2 , wherein, in the semiconductor layer, the third region is located between the first region and the second region. 
     
     
         5 . The display device according to  claim 2 , further comprising liquid crystal molecules provided over the pixel electrode. 
     
     
         6 . A display device comprising:
 a first wiring and a second wiring extending in a first direction;   a third wiring extending in a second direction intersecting the first direction;   a first transistor; and   a pixel electrode over the first transistor,   wherein the first transistor comprises:
 a gate electrode over a substrate; 
 a gate insulating layer over the gate electrode; 
 a semiconductor layer on the gate insulating layer; 
 a source electrode over and in contact with a first region of the semiconductor layer; and 
 a drain electrode over and in contact with a second region of the semiconductor layer, 
   wherein the semiconductor layer comprises a third region being thinner than each of the first region and the second region of the semiconductor layer,   wherein the first wiring comprises a first region configured to be the gate electrode of the first transistor,   wherein the second wiring comprises a first region overlapped with the pixel electrode,   wherein the first region of the second wiring extends in the second direction,   wherein the third wiring comprises a U-shaped region configured to be the source electrode of the first transistor, and   wherein the pixel electrode is electrically connected to the drain electrode.   
     
     
         7 . The display device according to  claim 6 , wherein the semiconductor layer comprises amorphous silicon. 
     
     
         8 . The display device according to  claim 6 , wherein, in the semiconductor layer, the third region is located between the first region and the second region. 
     
     
         9 . The display device according to  claim 6 , further comprising liquid crystal molecules provided over the pixel electrode. 
     
     
         10 . A display device comprising:
 a first wiring and a second wiring extending in a first direction;   a third wiring extending in a second direction intersecting the first direction;   a first transistor;   a first insulating layer over the first transistor; and   a pixel electrode over the first insulating layer,   wherein the first transistor comprises:
 a gate electrode over a substrate; 
 a gate insulating layer over the gate electrode; 
 an amorphous silicon layer on the gate insulating layer; 
 a source electrode over and in contact with a first region of the amorphous silicon layer; and 
 a drain electrode over and in contact with a second region of the amorphous silicon layer, 
   wherein the amorphous silicon layer comprises a third region being thinner than the first region and the second region of the amorphous silicon layer,   wherein the first wiring comprises a first region configured to be the gate electrode of the first transistor,   wherein the second wiring comprises a first region overlapped with the pixel electrode,   wherein the first region of the second wiring extends in the second direction,   wherein the third wiring comprises a U-shaped region configured to be the source electrode of the first transistor, and   wherein the pixel electrode is electrically connected to the drain electrode through an opening provided in the first insulating layer.   
     
     
         11 . The display device according to  claim 10 , wherein, in the amorphous silicon layer, the third region is located between the first region and the second region. 
     
     
         12 . The display device according to  claim 10 , further comprising liquid crystal molecules provided over the pixel electrode.