| 摘要 |
PROBLEM TO BE SOLVED: To obtain a full color displayable display memory medium which is capable of rapidly rewriting images by an external device, decreasing the voltage necessary for writing of the images and preventing the deterioration in display characteristics by the adhesion of dust, etc. SOLUTION: The display memory medium 1 is formed by laminating display layers 8A, 8B and 8C consisting of cholesteric liquid crystals which selectively reflect respective color light rays of blue, green and red, a light absorption layer 6 and a photoconductive layer 7 between substrates 2 and 3 formed with bias electrodes 10 and 11 on their inside surfaces. The threshold voltage of the respective cholesteric liquid crystals for the voltage to be impressed over the entire part of the display layers 8A, 8B and 8C is changed. An image writing device 12 is formed as a separate body from the display memory medium 1 and impresses bias voltage between the electrodes 10 and 11 for a voltage impression section 13 in a refreshing period and a selecting period and irradiate the photoconductive layer 7 with writing light 17 from a photoirradiation section 14. The voltage impressed over the entire part of the display layers 8A, 8B and 8C in the refreshing period and the selecting period is selected from plural stages of the voltage bordering at the threshold voltage described above.
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