Liquid crystal display device and driving method thereof

A method of driving a liquid crystal display, wherein the liquid crystal display comprises:

• a liquid crystal display panel having a matrix of a plurality of pixels arrayed two-dimensionally in a first direction and in a second direction crossing the first direction;
• a plurality of pixel rows each made up of a group of the pixels lined in the second direction, the pixel rows being arrayed in the first direction in the pixel matrix and sequentially selected in each frame period from one end of the pixel matrix to the other end;
• and
• an illuminating device having a plurality of light sources facing the pixel matrix of the liquid crystal display panel, the plurality of light sources being arrayed in the first direction and divided into at least three light source areas facing at least three groups of pixel rows;
• the liquid crystal display driving method repeating in each frame period the steps of:
• sequentially starting turn-on periods of the light source areas when one of the at least three groups of pixel rows corresponding to the at least three light source areas is selected and the plurality of pixels belonging to the selected group of pixel rows begin to receive video signals;
• after the turn-on periods of the at least three light source areas corresponding to the at least three groups of pixel rows have started, sequentially selecting again one of the at least three groups of pixel rows to put blanking signals for blanking the video signals into the re-selected group of pixel rows;
• and
• ending the turn-on periods of the at least three light source areas after one of the at least three groups of pixel rows has started to receive the blanking signals;
• wherein the at least three light source areas are divided into
• (i) a first light source area facing a middle area, with respect to the first direction, of the pixel matrix where a first group of the pixel rows is situated,
• (ii) a second light source area facing an area of the pixel matrix adjoining the middle area in the first direction where a second group of the pixel rows is situated which receives the video signals before the first group of the pixel rows in the each frame period, and
• (iii) a third light source area facing another area of the pixel matrix adjoining the middle area in the first direction where a third group of the pixel rows is situated which receives the video signals after the first group of the pixel rows in the each frame period;
• wherein the turn-on period of the second light source area, the turn-on period of the first light source area and the turn-on period of the third light source area sequentially start and end in that order;
• wherein the turn-on period of the second light source area ends after the turn-on period of the first light source area has started;
• wherein the turn-on period of the third light source area starts after the turn-on period of the first light source area has started and when or before the turn-on period of the second light source area ends;
• wherein, after the turn-on period of the first light source area has ended in the each frame period before the turn-on period of the first light source area starts in a next frame period, at least one of the turn-on periods of the second light source area and the third light source area is suspended.

A liquid crystal display comprising:

• a liquid crystal display panel having a matrix of a plurality of pixels arrayed two-dimensionally in a first direction and in a second direction crossing the first direction, the pixel matrix having a plurality of pixel rows each made up of a group of pixels lined in the second direction, the pixel rows being arrayed in the first direction and sequentially selected in each frame period from one end of the pixel matrix to the other end;
• an illuminating device having a plurality of light sources facing the pixel matrix of the liquid crystal display panel, the plurality of light sources being arrayed in the first direction and divided into at least three light source areas facing at least three groups of pixel rows;
• and
• a control unit including a display control circuit to give video signals to the pixel matrix and a light source driving circuit to control the driving of the plurality of light sources in response to a control signal from the display control circuit;
• wherein the control unit executes the following steps of:
• sequentially starting in the each frame period turn-on periods of the light source areas when one of the at least three groups of pixel rows corresponding to the at least three light source areas is selected and the plurality of pixels belonging to the selected group of pixel rows begin to receive video signals;
• sequentially ending the turn-on periods of the light source areas in the each frame period;
• using the at least three light source areas as a first light source area, a second light source area and a third light source area,
• the first light source area facing a middle area, with respect to the first direction, of the pixel matrix where a first group of the pixel rows is situated,
• the second light source area facing an area of the pixel matrix adjoining the middle area in the first direction where a second group of the pixel rows is situated which is selected before the first group of the pixel rows in the each frame period,
• the third light source area facing another area of the pixel matrix adjoining the middle area in the first direction where a third group of the pixel rows is situated which is selected after the first group of the pixel rows in the each frame period;
• sequentially starting and ending the turn-on period of the second light source area, the turn-on period of the first light source area and the turn-on period of the third light source area in that order;
• ending the turn-on period of the second light source area after the turn-on period of the first light source area has started;
• and
• starting the turn-on period of the third light source area after the turn-on period of the first light source area has started and when or before the turn-on period of the second light source area ends.