Passive matrix displays

M Arai, K Nakaya, O Onitsuka, T Inoue, M Codama, M Tanaka, and H Tanabe, Passive matrix display of organic LEDs, Synth. Met., 91 21-25, 1997. 

J. Bimstock, J. Biassing, A. Hunze, M. Stoel, K. Heuser, J. Worle, A. Winnacker, and G. Wittmann, Screen-printed passive matrix displays based on light-emitting polymers, Appl. Phys. Lett., 78 3905-3907, 2001. 

Kodak is commercialising its low molecular weight OLEDs for use in both passive and active matrix display architectures. It has also licensed its technology to Pioneer Corp who have commercialised passive matrix displays for car radios and cellular phone displays. TDK has displays for cellular phones, personal digital assistants and car instrumentation clusters. Perhaps the most significant collaboration to date has been with Sanyo. Sanyo s capabilities in low-temperature polycrystalline silicon have been married with Kodak s low MW materials to produce a full colour, 5 inch active matrix display, commercialisation of which was expected in 2001. 

Fig. 9.17. Passive matrix display and large-area OLED logos showing RGB and AIXTRON obtained by OVPD at TU Braunschweig.

Active-matrix displays differ from the aforementioned displays in that they have a switch incorporated into each pixel (Tsukada 2000). This removes the limitations encountered in passive matrix displays but requires more sophisticated processing equipment to be used. The dominant pixel switch technology is the amorphous silicon thin-film transistor (TFT) on glass (Tsukada 2000), although other technology... 

Fig. 10.17 Left a 96 by 64 pixel passive matrix display fabricated with Covion polymer. Right a flexible polymer LED. Reproduced with permission of Covion Organic Semiconductors GmbH.

The main difference between active matrix and passive matrix is image quality. Because the computer takes a millisecond or two to light the coordinates for a pixel in passive matrix displays, the response of the screen to rapid changes is poor, causing, for example, an effect known as submarining If, on a computer with a passive matrix display, you move the mouse rapidly from one location to another, it will disappear from the first location and reappear in the new location without appearing anywhere in between. 

The ability to process the luminescent semiconducting polymer from solution enables the introduction of simple and potentially inexpensive methods for manufacturing pixilated displays. There are two general classes of pixilated displays that differ in the manner in which the individual pixels are switched on and off passive matrix displays and active matrix displays. 

Flat panel displays are a necessary prerequisite for the full visual availability of information. After development of passive matrix displays used in digital watches, calculators [160] and portable computers, intensive work started in the development of large-area, full colour active matrix liquid crystal displays with high resolution. At the present time, LCDs are a major market force rivaling cathode ray tubes [157a],... 

If y < images with good contrast and high brightness can be displayed. In other words, for a given liquid crystal display, y is fixed. The maximum number of rows that the passive matrix display can have is given by... 

Fig. 7. Polymer LED passive matrix display 160 x 160 pixels with pitch of 300 )am. Picture provided by Nobel Laureate Dr. Alan J. Heeger, courtesy of Uniax Corp., Santa Barbara, Calif...

On the other hand, since 1995, active matrix displays have been predominant over passive matrix displays in the market. Notebook computers with displays from 10 to 13 inches have been the main application for active matrix LCDs. For this application, TN mode displays have been used and consequently demand for other modes has been limited. FLCs or AFLCs have little chance of being used for this application. 

E. Pozhidaev, V. Chigrinov, and X. Li, Photoahgned ferroelectric liquid crystal passive matrix display with memorized gray scale. Japanese Journal of Applied Physics 45, 875 (2006). 

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