PROBLEM TO BE SOLVED: To lessen visual unnaturality by distributing the respective display times of plural segments in respective frames over the entire part of the periods of these frames. SOLUTION: The display time of the bit plane of a bit with larger weight is divided to the smaller segments. The bit plane selected for the purpose of segmentation may be the arbitrary ≥1 bit planes exclusive of the bit plane of the least significant bit LSB. The display times for the segments are distributed over the entire part of the frame periods. The distribution is uniform throughout the frame period. For example, the eight segments of the display time for the most significant bit MSB (bit 7) are separated by the segments of the display times to the bits 6, 5, 4. The display times for the bits 3, 2, 1, 0 gather at the end part of the frame time. COPYRIGHT: (C)1997,JPO