Display apparatus
View Patent ↗A display apparatus divides each frame period of an input image signal into a plurality of subframes and selects the subframes according to a gray-scale level of the input signal, to display a gray-scale image. The display apparatus alternately employs two sets of tables having different gray-scale-level input/output characteristics, to move locations to cause false contours frame by frame, thereby minimizing false contours.
1. A display apparatus comprising:
a subframe coordinator configured to divide a frame period of an input image signal into subframes, brightness weights thereof increasing as a number of bits of the input image signal increases, and selecting at least one of the subframes that provides a brightness weight corresponding to an input gray-scale level specified by the input image signal, the subframes including a first subframe having a minimum brightness weight and a second subframe having a maximum brightness weight;
a table generator configured to generate first and second sets of subframe coding tables having the same gray-scale-level input/output characteristics in the first gray-scale-level range of 0 to a first value of input gray-scale level and having different gray-scale-level input/output characteristics in the second gray-scale-level range of a second value to a third value of input gray-scale level, the second value being one level larger than the first value and the third value being a maximum value of input gray-scale level; and
an image processing unit configured to cyclically and alternately employ the first and second sets of subframe coding tables at intervals of one frame, or one pixel, or one frame and one pixel of the input image signal and provide an output image signal having an output gray-scale level corresponding to the input gray-scale level, wherein:
the first and second sets of subframe coding tables generated by the table generator include data for selecting any subframes from the first subframe to the second subframe to emit light,
a subframe having a maximum brightness weight among subframes selected to emit light from the first subframe to the second subframe being the same for each group of input gray-scale levels in the second gray-scale-level range between the first and second sets of subframe coding tables,
the second gray-scale-level range of each set of subframe coding tables includes a plurality of groups each including input gray-scale levels including the same subframe selected to emit light and having the maximum brightness weight,
when the subframe selected to emit light and having the maximum brightness weight of a first group, which is a given group among the plurality of groups, is n, which is an integer indicating any subframe from the first subframe to the second subframe, the subframe selected to emit light and having the maximum brightness weight of a second group that is one next to the first group toward the second value is n−1,
any location of boundaries between the plurality of groups included in the second gray-scale-level range of the first set of subframe coding tables does not coincide with locations of boundaries of the second set of subframe coding tables.
2. The display apparatus of claim 1 , wherein:
the table generator generates the second set of subframe coding tables by linearly transforming the first set thereof of subframe coding tables.