Patent ID: 8179484

Claim:
A display medium comprising: a pair of electrodes; a photoconductive layer provided between the pair of electrodes, wherein the photoconductive layer exhibiting a distribution of an electrical characteristic according to a distribution of intensity of exposure light applied to the photoconductive layer in an electric field formed by a voltage applied to the pair of electrodes; a display layer, which is subjected to a divided voltage distributed according to the distribution of the electrical characteristic of the photoconductive layer imparted by the voltage applied to the pair of electrodes, which displays an image according to the divided voltage due to a distribution of an optical characteristics; and a selective light transmission layer provided between the photoconductive layer and the display layer, the ion concentration of the selective light transmission layer being from about 1.6×10 −6 (1.6 E−6, unit: C/cm 3 ) to about 2.5×10 −4 (2.5 E−4, unit: C/cm 3 ).