Liquid crystal display device

Abstract

It is an object to provide a liquid crystal display device which has excellent viewing angle characteristics and higher quality. The present invention has a pixel including a first switch, a second switch, a third switch, a first resistor, a second resistor, a first liquid crystal element, and a second liquid crystal element. A pixel electrode of the first liquid crystal element is electrically connected to a signal line through the first switch. The pixel electrode of the first liquid crystal element is electrically connected to a pixel electrode of the second liquid crystal element through the second switch and the first resistor. The pixel electrode of the second liquid crystal element is electrically connected to a Cs line through the third switch and the second resistor. A common electrode of the first liquid crystal element is electrically connected to a common electrode of the second liquid crystal element.

1 . (canceled) 
     
     
         2 . A display device comprising:
 a pixel electrode over a substrate; and   a thin film transistor electrically connected to the pixel electrode, the thin film transistor comprising:
 a first conductive layer comprising a portion which functions as a gate electrode; 
 a first insulating layer over the first conductive layer; 
 a semiconductor layer over the gate electrode with the first insulating layer interposed therebetween; 
 a second insulating layer on the semiconductor layer, the second insulating layer overlapping with the gate electrode; 
 a source electrode over the second insulating layer and electrically connected to the semiconductor layer; and 
 a drain electrode over the second insulating layer and electrically connected to the semiconductor layer, 
   wherein the second insulating layer is thinner than the first conductive layer;   wherein the second insulating is thinner than the source electrode and the drain electrode, and   wherein the thin film transistor comprises a channel region which comprises an oxide semiconductor.   
     
     
         3 . The display device according to  claim 2 , wherein the oxide semiconductor comprises zinc oxide. 
     
     
         4 . The display device according to  claim 2 , wherein the oxide semiconductor comprises indium, gallium and zinc. 
     
     
         5 . The display device according to  claim 2 , wherein the oxide semiconductor comprises indium. 
     
     
         6 . The display device according to  claim 2 , further comprising a second semiconductor layer between the semiconductor layer and the source electrode, wherein the second semiconductor layer is formed over the second insulating layer. 
     
     
         7 . A display device comprising:
 a first sub-pixel pixel and a second sub-pixel, each comprising:   a pixel electrode; and   a thin film transistor electrically connected to the pixel electrode, the thin film transistor comprising:
 a first conductive layer comprising a portion which functions as a gate electrode; 
 a first insulating layer over the first conductive layer; 
 a semiconductor layer over the gate electrode with the first insulating layer interposed therebetween; 
 a second insulating layer on the semiconductor layer, the second insulating layer overlapping with the gate electrode; 
 a source electrode over the second insulating layer and electrically connected to the semiconductor layer; and 
 a drain electrode over the second insulating layer and electrically connected to the semiconductor layer, 
   wherein the second insulating layer is thinner than the first conductive layer;   wherein the second insulating is thinner than the source electrode and the drain electrode, and   wherein the first thin transistor comprises a channel region which comprises an oxide semiconductor.   
     
     
         8 . The display device according to  claim 7 , wherein the oxide semiconductor comprises zinc oxide. 
     
     
         9 . The display device according to  claim 7 , wherein the oxide semiconductor comprises indium, gallium and zinc. 
     
     
         10 . The display device according to  claim 7 , wherein the oxide semiconductor comprises indium. 
     
     
         11 . The display device according to  claim 7 , further comprising a second semiconductor layer between the semiconductor layer and the source electrode, wherein the second semiconductor layer is formed over the second insulating layer. 
     
     
         12 . A display device comprising:
 a pixel electrode over a substrate; and   a thin film transistor electrically connected to the pixel electrode, the thin film transistor comprising:
 a first conductive layer comprising a portion which functions as a gate electrode; 
 a first insulating layer over the first conductive layer; 
 a semiconductor layer over the gate electrode with the first insulating layer interposed therebetween; 
 a second insulating layer on the semiconductor layer, the second insulating layer overlapping with the gate electrode; 
 a source electrode over the second insulating layer and electrically connected to the semiconductor layer; and 
 a drain electrode over the second insulating layer and electrically connected to the semiconductor layer, 
   wherein the semiconductor layer is thinner than the first conductive layer;   wherein the semiconductor layer is thinner than the source electrode and the drain electrode, and   wherein the first thin transistor comprises a channel region which comprises an oxide semiconductor.   
     
     
         13 . The display device according to  claim 12 , wherein the oxide semiconductor comprises zinc oxide. 
     
     
         14 . The display device according to  claim 12 , wherein the oxide semiconductor comprises indium, gallium and zinc. 
     
     
         15 . The display device according to  claim 12 , wherein the oxide semiconductor comprises indium. 
     
     
         16 . The display device according to  claim 12 , further comprising a second semiconductor layer between the semiconductor layer and the source electrode, wherein the second semiconductor layer is formed over the second insulating layer.