A flexible organic-light-emitting diode (OLED) with capability to show 16 million colors is fabricated on plastic barrier-film substrate, which can produce arbitrary shape with arbitrary colors, suitable for artistic expressions. Independently controlled red, green, and blue light-emitting layers are stacked vertically, so that no visible structure can be observed even with magnifiers from right-in-front measurement. In the past, large voltage drop of intermediate electrode was preventing this approach to be applied to actual electronic devices. However, according to the surface mobility control using Fick's law analysis, low sheet resistance 7.34 / on plastic film is developed, so that 7.17-cm 2 area emission is successfully achieved. With optical length optimization for each color stack, more than 100% color reproduction in National Television Committee Standard is achieved by stack design. The device can be used for colored illumination, as well as for organic-light-emitting display pixels for three times emission than the conventional pixel design. The device is fabricated on plastic substrate, so that the polychromatic OLED device is manufacturable with roll-to-roll production line.

Electronic paper (3.5 inch & 113 ppi) driven by active‐matrix using silver electrodeposition has been developed. It has a reflectivity of at least 60%, and a contrast ratio of at least 20, resulting in realizing visibility equivalent to paper. By discovering a new halogen‐free silver salt electrolyte composition, driving stability, a gray color tone, and bi‐stability have been considerably improved.

-A flexible vertically stacked flexible polychromatic color-tunable OLED has been developed by means of low resistive intermediate electrode technology. The polychromatic OLED has a capability to show 16 million colors with 105% National Television Committee Standard (NTSC) color reproduction. The device can produce arbitrary shape with arbitrary colors, suitable for artistic expressions, just as many as those used in information displays. Independently controlled red, green, and blue lightemitting layers are stacked vertically. With conventional indium tin oxide technology, because of the temperature restriction, it was quite difficult to achieve low resistance on plastic substrate. The reported numbers were all more than 80 Ω/□. According to the surface mobility control using Fick's law analysis, low sheet resistance 7.34 Ω/□ on plastic film was developed. At first, flexible 7.17 cm 2 transparent OLED was fabricated for the performance confirmation of transparent electrode. And then polychromatic color-tunable OLED with the same size were successfully fabricated on plastic. With optical length optimization for each color stack of polychromatic OLED, more than 100% color reproduction in National Television Committee Standard was achieved by stack design. The polychromatic device can be used for colored illumination, as well as for organic-light-emitting display pixels for three times emission than conventional pixel design. The device is fabricated on plastic substrate so that the polychromatic organic-light-emitting-diode device is manufacturable with roll-to-roll production line.

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A flexible vertically‐stacked flexible polychromatic color‐tunable OLED have been developed by means of low resistive intermediate electrode technology. The polychromatic OLED has capability to show 16 million colors with 105% NTSC color reproduction. The device can produce arbitrary shape with arbitrary colors, suitable for artistic expressions, just as many artistic painting are using. Independently controlled, red, green and blue light‐emitting layer are stacked vertically. With conventional ITO technology, due to the temperature restriction, it was quite difficult to achieve low resistance on plastic substrate. The reported numbers were all more than 80Ω/ɑ. According to the surface mobility control using Fick's law analysis, low sheet resistance 7.34Ω/ɑ on plastic film was developed. At first, flexible 7.17 cm2 transparent OLED was fabricated for the performance confirmation of transparent electrode. And then polychromatic colortunable OLED with the same size were successfully fabricated on plastic. With optical length optimization for each color stack of polychromatic OLED, more than 100% color reproduction in National Television Committee Standard was achieved by stack design. The polychromatic device can be used for colored illumination, as well as for organic‐light‐emitting display pixels for three times emission than conventional pixel design. The device is fabricated on plastic substrate so that the polychromatic organic‐light‐emitting‐diode device is manufacturable with roll‐to‐roll production line.