Liquid Crystal Display Device and Driving Method Thereof

Abstract

In a display device including a backlight and a display panel, the area of the backlight is divided into a plurality of unit regions; the display panel includes pixels which are larger in number than the unit regions; a frame rate of image data input to the device is converted to perform display while part of the unit regions in which black is displayed is in a non-light emission state; and the driving frequency of the backlight is converted in accordance with the display.

What is claimed is: 
     
         1 . (canceled) 
     
     
         2 . A liquid crystal display device comprising a display panel, the display panel comprising:
 a first substrate and a second substrate;   a spacer interposed between the first substrate and the second substrate;   a light-shielding film overlapping with the spacer; and   a pixel portion on the first substrate, the pixel portion comprising:
 a video signal line comprising a first conductive layer and oriented along a column direction; 
 a common electrode comprising a second conductive layer; and 
 pixels arranged in lines and columns, each pixel of a given column comprising a semiconductor layer, a pixel electrode connected to the video signal line via the semiconductor layer, the semiconductor layer overlapping and being in electrical contact with the first conductive layer; 
   wherein the spacer overlaps with one of the semiconductor layers,   wherein the columns are parallel to the column direction,   wherein a first portion of a first pixel electrode is oblique with respect to and makes a first angle with the column direction,   wherein a second portion of a second pixel electrode is oblique with respect to and makes a second angle with the column direction, the first angle being different from the second angle,   wherein the first conductive layer comprises a first portion and a second portion parallel to the first portion of the first pixel electrode and to the second portion of the second pixel electrode, respectively, and   wherein the second conductive layer is continuously formed so as to overlap with the first portion of the first pixel electrode, with a second portion of the first pixel electrode parallel to the first portion of the first pixel electrode, and with a totality of a space separating the first portion and the second portion of the first pixel electrode.   
     
     
         3 . The liquid crystal display device comprising a display panel according to  claim 2 ,
 wherein the video signal line does not overlap with a portion of the second conductive layer comprising physical edges making the first angle with the column direction.   
     
     
         4 . The liquid crystal display device comprising a display panel according to  claim 2 ,
 wherein the second conductive layer overlaps with the second pixel electrode, and   wherein the first pixel electrode and the second pixel electrode belong to two pixels of the given column adjacent to each other.   
     
     
         5 . A liquid crystal display device comprising a display panel, the display panel comprising:
 a first substrate and a second substrate;   a spacer interposed between the first substrate and the second substrate;   a light-shielding film overlapping with the spacer; and   a pixel portion on the first substrate, the pixel portion comprising:
 a video signal line comprising a first conductive layer and oriented along a column direction; 
 a common electrode comprising a second conductive layer; and 
 pixels arranged in lines and columns, each pixel of a given column comprising a semiconductor layer, a pixel electrode connected to the video signal line via the semiconductor layer, the semiconductor layer overlapping and being in electrical contact with the first conductive layer; 
   wherein the spacer overlaps with one of the semiconductor layers,   wherein the columns are parallel to the column direction,   wherein a first portion of a given pixel electrode is oblique with respect to and makes a first angle with the column direction,   wherein a second portion of the given pixel electrode is oblique with respect to and makes a second angle with the column direction, the first angle being different from the second angle,   wherein the first conductive layer comprises a first portion and a second portion parallel to the first portion and to the second portion of the given pixel electrode, respectively, and   wherein the second conductive layer is continuously formed so as to overlap with two portions of the given pixel electrode parallel to each other, and with a totality of a space separating the two portions of the given pixel electrode parallel to each other.   
     
     
         6 . The liquid crystal display device comprising a display panel according to  claim 2 ,
 wherein the pixel electrodes overlap with the common electrode.   
     
     
         7 . The liquid crystal display device comprising a display panel according to  claim 5 , wherein the pixel electrodes overlap with the common electrode. 
     
     
         8 . A liquid crystal display device comprising a display panel, the display panel comprising:
 a first substrate and a second substrate;   a spacer interposed between the first substrate and the second substrate;   a light-shielding film overlapping with the spacer; and   a pixel portion on the first substrate, the pixel portion comprising:
 a video signal line comprising a first conductive layer and oriented along a column direction; 
 a common electrode comprising a second conductive layer; and 
 pixels arranged in lines and columns, each pixel of a given column comprising a semiconductor layer, a pixel electrode connected to the video signal line via the semiconductor layer, the semiconductor layer overlapping and being in electrical contact with the first conductive layer; 
   wherein the spacer overlaps with one of the semiconductor layers,   wherein the columns are parallel to the column direction,   wherein a first portion of a given pixel electrode is oblique with respect to and makes a first angle with the column direction,   wherein a second portion of the given pixel electrode is oblique with respect to and makes a second angle with the column direction, the first angle being different from the second angle,   wherein the first conductive layer comprises a first portion and a second portion parallel to the first portion and to the second portion of the given pixel electrode, respectively,   wherein the second conductive layer is continuously formed so as to overlap with two portions of the given pixel electrode parallel to each other, and with a totality of a space separating the two portions of the given pixel electrode parallel to each other, and   wherein the video signal line does not overlap with a portion of the second conductive layer comprising a physical edge making the first angle with the column direction.   
     
     
         9 . The liquid crystal display device comprising a display panel according to  claim 8 ,
 wherein the second conductive layer overlaps with the pixel electrodes of two pixels of the given column adjacent to each other.   
     
     
         10 . The liquid crystal display device comprising a display panel according to  claim 2 ,
 wherein the first pixel electrode comprises portions parallel to each other with a space therebetween, the first portion being one of the portions parallel to each other.   
     
     
         11 . The liquid crystal display device comprising a display panel according to  claim 5 ,
 wherein the given pixel electrode comprises portions parallel to each other with a space therebetween, the first portion being one of the portions parallel to each other.   
     
     
         12 . The liquid crystal display device comprising a display panel according to  claim 8 ,
 wherein the given pixel electrode comprises portions parallel to each other with a space therebetween, the first portion being one of the portions parallel to each other.   
     
     
         13 . The liquid crystal display device comprising a display panel according to  claim 2 ,
 wherein the first pixel electrode is bent comb-shaped.   
     
     
         14 . The liquid crystal display device comprising a display panel according to  claim 5 ,
 wherein the given pixel electrode is bent comb-shaped.   
     
     
         15 . The liquid crystal display device comprising a display panel according to  claim 8 ,
 wherein the given pixel electrode is bent comb-shaped.   
     
     
         16 . The liquid crystal display device comprising a display panel according to  claim 2 ,
 wherein the light-shielding film is on the second substrate.   
     
     
         17 . The liquid crystal display device comprising a display panel according to  claim 5 ,
 wherein the light-shielding film is on the second substrate.   
     
     
         18 . The liquid crystal display device comprising a display panel according to  claim 8 ,
 wherein the light-shielding film is on the second substrate.   
     
     
         19 . The liquid crystal display device comprising a display panel according to  claim 2 ,
 wherein the semiconductor layers are amorphous silicon layers or polycrystalline silicon layers.   
     
     
         20 . The liquid crystal display device comprising a display panel according to  claim 5 ,
 wherein the semiconductor layers are amorphous silicon layers or polycrystalline silicon layers.   
     
     
         21 . The liquid crystal display device comprising a display panel according to  claim 8 ,
 wherein the semiconductor layers are amorphous silicon layers or polycrystalline silicon layers.   
     
     
         22 . The liquid crystal display device comprising a display panel according to  claim 2 ,
 wherein the first conductive layer and the second conductive layer do not overlap.   
     
     
         23 . The liquid crystal display device comprising a display panel according to  claim 5 ,
 wherein the first conductive layer and the second conductive layer do not overlap.   
     
     
         24 . The liquid crystal display device comprising a display panel according to  claim 8 ,
 wherein the first conductive layer and the second conductive layer do not overlap.   
     
     
         25 . The liquid crystal display device comprising a display panel according to  claim 2 , further comprising a backlight,
 wherein the backlight is divided into a plurality of unit regions configured so that brightness of each of the plurality of unit regions is individually controlled,   wherein the pixels are larger in number than the plurality of unit regions,   wherein the backlight is configured to have a period during which the brightness of each of the plurality of unit regions is controlled in accordance with gray scale levels of images, and   wherein a maximum brightness of the plurality of unit regions when displaying one of the images is determined in accordance with an average value of gray scale levels of the one of the images so that the maximum brightness is increased when the average value is reduced and the maximum brightness is decreased when the average value is increased.   
     
     
         26 . The liquid crystal display device comprising a display panel according to  claim 5 , further comprising a backlight,
 wherein the backlight is divided into a plurality of unit regions configured so that brightness of each of the plurality of unit regions is individually controlled,   wherein the pixels are larger in number than the plurality of unit regions,   wherein the backlight is configured to have a period during which the brightness of each of the plurality of unit regions is controlled in accordance with gray scale levels of images, and   wherein a maximum brightness of the plurality of unit regions when displaying one of the images is determined in accordance with an average value of gray scale levels of the one of the images so that the maximum brightness is increased when the average value is reduced and the maximum brightness is decreased when the average value is increased.   
     
     
         27 . The liquid crystal display device comprising a display panel according to  claim 8 , further comprising a backlight,
 wherein the backlight is divided into a plurality of unit regions configured so that brightness of each of the plurality of unit regions is individually controlled,   wherein the pixels are larger in number than the plurality of unit regions,   wherein the backlight is configured to have a period during which the brightness of each of the plurality of unit regions is controlled in accordance with gray scale levels of images, and   wherein a maximum brightness of the plurality of unit regions when displaying one of the images is determined in accordance with an average value of gray scale levels of the one of the images so that the maximum brightness is increased when the average value is reduced and the maximum brightness is decreased when the average value is increased.