Method for driving liquid crystal display device

Abstract

In a field-sequential liquid crystal display device, image quality and detection accuracy in image capture are improved by increasing the frequency of input of image signals and securing a sufficient imaging period. Image signals are concurrently supplied to pixels provided in a plurality of rows among pixels arranged in matrix. Further, image capture is concurrently performed in pixels provided in a plurality of rows among pixels arranged in matrix. Thus, the frequency of input of an image signal to each pixel of the liquid crystal display device can be increased and a sufficient imaging period can be secured. As a result, in the liquid crystal display device, display deterioration such as color break which is caused in a field-sequential liquid crystal display device can be suppressed and improvements in image quality and detection accuracy in image capture can be realized.

1 . A method for driving a liquid crystal display device comprising first light sources, second light sources and a pixel portion, the pixel portion comprising display pixels in m rows and n columns and image-capture pixels in x rows and y columns (m, n, x and y are natural numbers of 4 or more), comprising the steps of:
 performing first supply of an image signal of a first color for the display pixels in first to k-th rows sequentially (k is a natural number of less than m/2) in a first period;   performing second supply of an image signal of the first color for the display pixels in (k+1)-th to 2k-th rows sequentially in the first period;   emitting light of the first color through the display pixels in first to 2k-th rows after the first period;   performing a first image capture in the image-capture pixels in first to z-th rows sequentially (z is a natural number of less than x/2) while emitting the light; and   performing a second image capture in the image-capture pixels in (z+1)-th to 2z-th rows sequentially while emitting the light,   wherein the first supply and the second supply are performed concurrently,   wherein the first image capture and the second image capture are performed concurrently,   wherein the first light sources emit light of the first color, and   wherein the second light sources emit light of a second color.   
     
     
         2 . The method for driving the liquid crystal display device according to  claim 1 , further comprising the step of:
 shutting off the first light sources and the second light sources after the first period and before emitting the light of the first color.   
     
     
         3 . The method for driving the liquid crystal display device according to  claim 1 , further comprising the steps of:
 performing third supply of an image signal of the second color for the display pixels in the first to k-th rows sequentially (k is a natural number of less than m/2) in a second period;   performing fourth supply of an image signal of the second color for the display pixels in the (k+1)-th to 2k-th rows sequentially in the second period; and   shutting off the first light sources and the second light sources in the second period,   wherein the third supply and the fourth supply are performed concurrently.   
     
     
         4 . The method for driving the liquid crystal display device according to  claim 2 ,
 wherein common inversion driving is performed while shutting off the first light sources and the second light sources after emitting the light of the first color.   
     
     
         5 . The method for driving the liquid crystal display device according to  claim 1 , wherein the first light sources and the second light sources are shut off after a period for producing one image in the pixel portion. 
     
     
         6 . A method for driving a liquid crystal display device comprising first light sources, second light sources and a pixel portion, the pixel portion comprising display pixels in m rows and n columns and image-capture pixels in x rows and y columns (m, n, x and y are natural numbers of 4 or more), comprising the steps of:
 performing first supply of an image signal of a first color for the display pixels in first to k-th rows sequentially (k is a natural number of less than m/2) in a period;   performing second supply of an image signal of a second color for the display pixels in (k+1)-th to 2k-th rows sequentially in the period;   shutting off the first light sources and the second light sources after performing the first supply for the display pixels in the first to s-th rows and the second supply for the display pixels in the (k+1)-th to (k+s)-th rows and before emitting the light of the first color and the light of the second color;   emitting light of the first color for the display pixels in first to s-th rows and light of the second color for the display pixels in (k+1)-th to (k+s)-th rows (s is a natural number of k/2 or less) in the period and after the first supply for the display pixels in the first to s-th rows and the second supply for the display pixels in the (k+1)-th to (k+s)-th rows are finished;   performing a first image capture in the image-capture pixels in first to v-th rows sequentially (v is a natural number of x/4 or less) while emitting the light of the first color; and   performing a second image capture in the image-capture pixels in (w+1)-th to (w+v)-th rows sequentially (w is a natural number greater than or equal to 2v and less than or equal to x/2) while emitting the light of the second color,   wherein the first supply and the second supply are performed concurrently,   wherein the first image capture and the second image capture are performed concurrently,   wherein the first light sources emit light of the first color,   wherein the second light sources emit light of the second color,   wherein the liquid crystal display device further comprises a first image-capture signal line and a second image-capture signal line which are provided for each column of the image-capture pixels,   wherein in each column, the image-capture pixels in the first to v-th rows are connected to the first image-capture signal line and the image-capture pixels in the (w+1)-th to (w+v)-th rows are connected to the second image-capture signal line,   wherein the first image capture is performed by determining a potential of the first image-capture signal line and the second image capture is performed by determining a potential of the second image-capture signal line, and   wherein the pixel portion comprises a first region which includes the display pixels in the first to k-th rows and the image-capture pixels in the first to v-th rows and a second region which includes the display pixels in the (k+1)-th to 2k-th rows and the image-capture pixels in the (w+1)-th to (w+v)-th rows.   
     
     
         7 . A method for driving a liquid crystal display device comprising first light sources, second light sources and a pixel portion, the pixel portion comprising display pixels in m rows and n columns and image-capture pixels in x rows and y columns (m, n, x and y are natural numbers of 4 or more), comprising the steps of:
 performing first supply of an image signal of a first color for the display pixels in first to k-th rows sequentially (k is a natural number of less than m/2) in a period;   performing second supply of an image signal of a second color for the display pixels in (k+1)-th to 2k-th rows sequentially in the period;   emitting light of the first color for the display pixels in first to s-th rows and light of the second color for the display pixels in (k+1)-th to (k+s)-th rows (s is a natural number of k12 or less) in the period and after the first supply for the display pixels in the first to s-th rows and the second supply for the display pixels in the (k+1)-th to (k+s)-th rows are finished;   performing a first image capture in the image-capture pixels in first to v-th rows sequentially (v is a natural number of x/4 or less) while emitting the light of the first color; and   performing a second image capture in the image-capture pixels in (w+1)-th to (w+v)-th rows sequentially (w is a natural number greater than or equal to 2v and less than or equal to x/2) while emitting the light of the second color,   wherein the first supply and the second supply are performed concurrently,   wherein the first image capture and the second image capture are performed concurrently,   wherein the first light sources emit light of the first color,   wherein the second light sources emit light of the second color,   wherein the liquid crystal display device further comprises a first image-capture signal line and a second image-capture signal line which are provided for each column of the image-capture pixels,   wherein in each column, the image-capture pixels in the first to v-th rows are connected to the first image-capture signal line and the image-capture pixels in the (w+1)-th to (w+v)-th rows are connected to the second image-capture signal line,   wherein the first image capture is performed by determining a potential of the first image-capture signal line and the second image capture is performed by determining a potential of the second image-capture signal line,   wherein the pixel portion comprises a first region which includes the display pixels in the first to k-th rows and the image-capture pixels in the first to v-th rows and a second region which includes the display pixels in the (k+1)-th to 2k-th rows and the image-capture pixels in the (w+1)-th to (w+v)-th rows, and   wherein the first light sources and the second light sources are shut off in a black insertion period and after a period for producing one image in the pixel portion.   
     
     
         8 . The method for driving the liquid crystal display device according to  claim 7 , wherein common inversion driving is performed in the black insertion period.