Display device and light source

Abstract

A display device according to the present invention includes: a gate driver for sequentially display scanning pixels in a first direction of a TFT liquid crystal panel to set pixels to display states according to information displayed by the pixels in the TFT liquid crystal panel, the pixels arranged in two dimensions and their display state being individually controllable through illumination; and a backlight unit for illuminating the individual pixels with intensity of light which increases and decreases in synchronism with the display scanning of the gate driver after the display scanning. The arrangement enables the backlight flashing period to be determined independently from a TFT panel scanning period or response time of liquid crystal. The arrangement also ensures an extended operating time of a TFT panel; effects a display period equal to, or longer than, the black blanking type; and achieves higher contrast than the black blanking type.

1 . A display device comprising:
 a plurality of light sources providing illumination that approximates an image;   a display panel having a display region divided into a plurality of display panel areas, each of which receives light from the light sources;   a plurality of display elements provided in the display panel areas that control transmittance of light emitted by said light sources; and   a light amount controller operatively connected to said light sources that controls the light sources by calculating light control amounts according to an image information signal, which is indicative of an image for display by the display device.   
     
     
         2 . The display device as defined in  claim 1 , wherein each of the display elements includes at least one switching element. 
     
     
         3 . The display device as defined in  claim 2 , further comprising:
 a plurality of switches, each electronically connected to at least one of the plurality of light sources and   a switch controlling the plurality of switches to sequentially turn on the plurality of light sources.   
     
     
         4 . The display device as defined in  claim 3 , further comprising:
 a plurality of source electrodes and a plurality of gate electrodes arranged in a matrix and electronically connected to at least one switching element in each of the display elements and   a gate driver applying a gate-ON voltage to the plurality of gate electrodes to sequentially turn on the switching elements in each of the display elements, wherein the gate driver initiates sequentially turning on the switching elements a predetermined period of time before the switch controller initiates sequentially turning on the plurality of light sources.   
     
     
         5 . The display device as defined in  claim 1 , wherein several of the display panel areas correspond to one of the light source areas. 
     
     
         6 . The display device as defined in  claim 1 , wherein several of the display panel areas within at least one common row correspond to one of the light source areas. 
     
     
         7 . The display device as defined in  claim 5 , wherein said light amount controller calculates the light control amounts based on maximum value of the image information signal of the corresponding display panel areas. 
     
     
         8 . The display device as defined in  claim 6 , wherein said light amount controller calculates the light control amounts in proportion to the maximum value of the image information signal of the corresponding display panel areas. 
     
     
         9 . The display device as defined in  claim 1 , wherein said light amount controller calculates the light control amounts based on a dynamic range of the display device. 
     
     
         10 . The display device as defined in  claim 9 , wherein said light amount controller calculates the light control amounts in reverse proportion to the dynamic range of the display device. 
     
     
         11 . The display device as defined in  claim 1 , wherein the light control amount is a lighting period. 
     
     
         12 . The display device as defined in  claim 11 , wherein said light amount controller calculates the light control amount in a range not less than zero and not more than 50 percent of a field period of the display panel. 
     
     
         13 . The display device as defined in  claim 1 , wherein the light control amount is intensity of light. 
     
     
         14 . The display device as defined in  claim 13 , said light amount controller including a lighting circuit connected to said light sources, said lighting circuit lighting the light sources based on the light control amount 
     
     
         15 . The display device as defined in  claim 14 , wherein the lighting circuit varies the intensity of light by varying an output voltage for each of the light sources. 
     
     
         16 . The display device as defined in  claim 1 , further comprising a delay circuit compensating for operational delay of the light amount controller. 
     
     
         17 . The display device as defined in  claim 16 , wherein the delay circuit is a memory. 
     
     
         18 . The display device as defines in  claim 1 , said light amount controller including a lighting circuit connected to said light sources, said lighting circuit lighting the light sources based on the light control amount wherein:
 a plurality of the light sources are connected in parallel to the lighting circuit and   the display device includes a plurality of switching elements, each of which is connected in series to each of the light sources.   
     
     
         19 . The display device as defines in  claim 1 , wherein the light sources are fluorescent tubes. 
     
     
         20 . The display device as defined in  claim 1 , wherein:
 the light control amount corresponds to a flashing period of the light sources and   the light amount controller varies a flashing period of at least one of the light sources according to a maximum value of the image information signal for a portion to be illuminated by the at least one of the light sources.   
     
     
         21 . The display device as defined in  claim 20 , wherein the flashing period of the at least one of the light sources is varied in direct proportion to the maximum value. 
     
     
         22 . The display device as defined in  claim 1 , wherein:
 the light control amount corresponds to an intensity of the light sources, and   the light amount controller varies an intensity of at least one of the light sources according to a maximum value of the image information signal for a portion to be illuminated by the at least one of the light sources.   
     
     
         23 . The display device as defined in  claim 22 , wherein the intensity of the at least one of the light sources is varied in direct proportion to the maximum value. 
     
     
         24 . The display device as defined in  claim 23 , wherein the intensity of the at least one of the light sources is varied by varying an output voltage for the at least one of the light sources.