Abstract: The image display device includes a front CF-less liquid crystal panel, a first light guide plate, a PDLC panel, and a rear CF-less liquid crystal panel that are arranged sequentially, and a light-guide plate light source unit. At an image displaying time, the PDLC panel becomes in a spreading state. At this time, light source light emitted by the light-guide plate light source unit is guided to the first light guide plate, and is applied to the PDLC panel. The light source light spread by the PDLC panel is applied to the front CF-less liquid crystal panel and the rear CF-less liquid crystal panel. At an image non-displaying time, the PDLC panel becomes in a transmittance state, and transmits background light.

Abstract: A data coding system is arranged such that character font data is compressed in a unit of 4-bit in a form of a bit string with a compression width of 4-bit in the Huffman coding system. The data coding system employs a code structure in the Huffman coding system for respectively converting three bit strings selected in order from that of the highest appearance frequency in a unit of 4-bit in the character font data into the compressed codes expressed using not more than 3 bits. The described system permits a significantly improved compression rate of the character font data into respective compressed codes.