Display control circuit, liquid crystal display device including the same, and display control method
An object of the present invention is to suppress a reduction in image quality caused by crosstalk in a liquid crystal display device capable of performing 3D display. A predetermined number of pixels (e.g., pixels of two rows×two columns) having the same gray scale value are divided into pixels (first pixel group) whose post-correction gray scale values are the same between a left-eye image and a right-eye image, and pixels (second pixel group) whose post-correction gray scale values are different between the left-eye image and the right-eye image. For example, an average value between a pre-correction gray scale value of the left-eye image and a pre-correction gray scale value of the right-eye image is a post-correction gray scale value of the first pixel group. The post-correction gray scale values of the second pixel group are determined such that, for both of the left-eye image and the right-eye image, an average gray scale value of each group including the predetermined number of pixels is not changed between before and after the correction.
1. A display control circuit that generates write gray scale data to be provided to a display device, based on an image signal including left-eye gray scale data and right-eye gray scale data, the display device displaying a 3D image by alternately displaying a left-eye image and a right-eye image, the display control circuit comprising:
a gray scale correction circuit that corrects the image signal such that an average gray scale value of each of groups is not changed between before and after the correction, each group including a predetermined number of pixels adjacent to each other, and the pixels having a same gray scale value indicated by the left-eye gray scale data and having a same gray scale value indicated by the right-eye gray scale data; and
an overshoot drive circuit that generates the write gray scale data by performing correction on the image signal corrected by the gray scale correction circuit, to emphasize a temporal change of the signal, wherein
the gray scale correction circuit divides the predetermined number of pixels included in each group into a first pixel group and a second pixel group, and corrects the image signal such that a post-correction gray scale value for the left-eye gray scale data and a post-correction gray scale value for the right-eye gray scale data are equal to each other for at least the first pixel group.
2. The display control circuit according to claim 1 , wherein
a post-correction gray scale value GM for the left-eye gray scale data and the right-eye gray scale data for the first pixel group is calculated by a following equation:
GM =( GL+GR )/2
where GL represents a pre-correction gray scale value for the left-eye gray scale data, and GR represents a pre-correction gray scale value for the right-eye gray scale data.
3. The display control circuit according to claim 1 , wherein
the gray scale correction circuit corrects, for the second pixel group, the image signal such that a gray scale value for the left-eye gray scale data or a gray scale value for the right-eye gray scale data is not changed between before and after the correction.
4. The display control circuit according to claim 1 , further comprising a gray scale correction look-up table that stores a first input value, a second input value, and an output value corresponding to a combination of the first input value and the second input value, wherein
with a pre-correction gray scale value for the left-eye gray scale data being the first input value and a pre-correction gray scale value for the right-eye gray scale data being the second input value, the gray scale correction circuit extracts an output value from the gray scale correction look-up table, and uses the extracted output value as a post-correction gray scale value for the left-eye gray scale data and the right-eye gray scale data for the first pixel group.
5. A liquid crystal display device comprising:
the display control circuit according to claim 1 ;
a display unit including: a plurality of video signal lines for transmitting a plurality of video signals corresponding to the write gray scale data; a plurality of scanning signal lines intersecting the plurality of video signal lines; a plurality of pixel formation portions arranged in a matrix along the plurality of video signal lines and the plurality of scanning signal lines; and a common electrode that provides a common potential to the plurality of pixel formation portions;
a video signal line drive circuit that drives the plurality of video signal lines; and
a scanning signal line drive circuit that drives the plurality of scanning signal lines.
6. A display control method for generating write gray scale data to be provided to a display device, based on an image signal including left-eye gray scale data and right-eye gray scale data, the display device displaying a 3D image by alternately displaying a left-eye image and a right-eye image, the method comprising:
a gray scale correction step of correcting the image signal such that an average gray scale value of each of groups is not changed between before and after the correction, each group including a predetermined number of pixels adjacent to each other, and the pixels having a same gray scale value indicated by the left-eye gray scale data and having a same gray scale value indicated by the right-eye gray scale data; and
an overshoot drive step of generating the write gray scale data by performing correction on the image signal corrected in the gray scale correction step, to emphasize a temporal change of the signal, wherein
in the gray scale correction step, the predetermined number of pixels included in each group are divided into a first pixel group and a second pixel group, and the image signal is corrected such that a post-correction gray scale value for the left-eye gray scale data and a post-correction gray scale value for the right-eye gray scale data are equal to each other for at least the first pixel group.