Flexible plastic display

There is a rising demand for conductive or electrostatic discharge (BSD) compounds in the electronics industry for packaging and handling purposes and for use in semiconductors and disc drives. New flexible plastic displays will be produced in large munbers to show video images. 

Unstable state of plastic as evidenced by changes in physical )roperties not caused by the surroundings. Example is the temporary flexible condition some plastics display after molding. Assembly of all parts making up an injection mold, excluding cavity, cores and pins. 

Y. Hong and J. Kanicki, Organic polymer light-emitting devices on flexible plastic substrates for AM-OPLED, Proc. Asia Display/IDW 01, 1443-1446, 2001. 

Project (by Sarnoff Corp with DuPont de Nemours and Co Central Research and Development) to print organic transistors on plastic for electronic displays and circuits. The goal is to develop materials, thin flexible plastic substrates, and methods for continuous high-resolution printing. 

Fig. 10.17. Mechanically flexible plastic active matrix circuit (left frame) for an electronic paperlike display (right frame). Micro-contact printing defined the critical features in the circuit.

Although there have been several examples of flexible OLED displays on plastics, including passive-matrix OLED displays on poly(ethylene terephthalate) (PET) substrates from Pioneer and Universal Display Corporation [26, 27], and a-Si H TFT-driven monochrome active-matrix OLED displays on poly(ethylene naphthalate) (PEN) from Honeywell [28], there have been no demonstrations of organic TFT-... 

K. R. Sarma, J. Schmidt, J. Roush, C. Chanley, S. Dodd, AMOLED using a-Si TFT backplane on flexible plastic substrate, presented at Proc SPIE, Defense, Security, and Cockpit Displays, Orlando, Florida, USA, 2004. 

The year 1990 marked the debut of a new class of TFT, based upon organic semiconductor active layer material, with electron mobilities similar to that of a-Si H. These new TFTs are very promising candidates for integration onto flexible plastic substrates for a future generation of rugged, lightweight displays than can be rolled up like a map. 

Fig. VII-1 shows a schematic of the structure of a polymer LED and a picture of a thin film flexible polymer LED seven-segment display. The bottom electrode of this display was made by spin-cas ting a layer of metallic polyaniline onto a flexible plastic substrate [69]. Polyaniline was chosen as the electrode material because it is flexible, conducts current, and is transparent to visible light. The emissive layer of the display was fo med by spin casting a layer of MEH-PPV over the polyaniline. The top electrodes were formed by evaporating calcium through a patterned shadow mask. Since the conductivity of undoped emissive polymers is relatively low, it was not necessary to pattern the polymer or the bottom electrode to prevent current spreading between neighboring pixels.

Another important applieation field for printable electronics are backplanes for active-matrix displays. These baekplanes, which contain up to several millions of transistors, ideally will be fully printed. When flexible plastic substrates are used, the displays can be bendable and rollable while retaining their original performance. The stacked layers of materials are extremely thin, in the order of hundreds of nanometers, and therefore light-weight ideal properties for an E-book reader. 

Fig. 4.1 shows a schematic of the structure of a polymer LED. A photo of a thin-film flexible seven-segment display fabricated from a semiconducting polymer is shown in Fig. 4.2. The bottom electrode (the anode) of this flexible display was made by spin-casting a layer of metallic polyaniline onto a flexible plastic substrate [12].

Coefficient of Friction. This property depends on styrene level and on materials which may be added in ccanpomding but falls in the same range as other rubbers (natural rubber, S B, etc.) rather than in a lower range displayed by even the more flexible plastics. 

Fig. 7.11 Photos of a PANl-based flexible electrochromic display device containing 25 pixels. The display region and the connections were made by depositing gold on a plastic sheet using an appropriate mask and an evaporation technique. Each pixel can be driven separately. Left. PANI is in its oxidized state in all pixels. Right. PANI is reduced in two pixels (the bleached ones)...

Therefore, liquid-phase processible organic semiconductors need to be used so that low-cost large area electronics with flexible plastic substrates for display or data storage can be realized by using printing techniques. 

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