Method for driving liquid crystal display device

A method for driving a liquid crystal display device comprising first light sources, second light sources, infrared light sources, a detection circuit, an image sensor driver circuit, a scan line driver circuit 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 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 utilizing light of the first color and light whose wavelength is in infrared region in the image-capture pixels in first to v-th rows sequentially (v is a natural number of x/4 or less) while lighting the first light sources and the infrared light sources;
• and
• performing a second image capture utilizing light of the second color and light whose wavelength is in infrared region 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 lighting the second light sources and the infrared light sources,
• wherein the first color and the second color are different from each other,
• wherein an image of the first color is obtained by the first image capture and an image of the second color is obtained by the second image capture,
• wherein the first supply and the second supply 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 first image capture and the second image capture are performed concurrently,
• wherein the liquid crystal display device further comprises a first image-capture signal line and a second image-capture signal line which are parallel to each other and 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 by the detection circuit and the second image capture is performed by determining a potential of the second image-capture signal line by the detection circuit,
• 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 second region includes the first image-capture signal line and the second image-capture signal line.