Passive Matrix Addressing

The electrodes are patterned to form a number of parallel conductive lines. Both electrodes are oriented at right angles to form a set of N row electrodes and M column electrodes. This is shown schematically in Fig. 9 for a display consisting with N=M=2. The number of active areas or pixels P=NxM can be addressed by P//V+IV individual connections. The addressing of a black and white VGA display thus requires 1120 connections. Each pixel of the matrix is addressed by applying voltage pulses to row and column electrodes. The N rows are sequentially addressed by voltage pulses of 

The corresonding r.m.s. voltage across one pixel in the on or off state is given by 

This ratio is optimized by differenting Eq. (8) with respect to S/D and setting this equation equal to zero. This results in 

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Displays based on OLEDs may be addressed either passively or actively [124], and the drive requirements are quite different in each case. In passive-matrix addressing, the display is addressed one line at a time, so if a display has 480 lines then a pixel can only be emitting for... 

Lueder, E. (2001). Liquid Crystal Displays Active and Passive Matrix Addressing Techniques, Wiley, New York. 

T. Tanaka, Y. Sato, A. Inoue, et al., A bistable twisted nematic (BTN) LCD driven by a passive-matrix addressing, Proc. Asia Display 95, 259 (1995). 

The problems with the passive-matrix addressing can be solved by the active-matrix addressing method, where each pixel is addressed via a transistor integrated to the pixels. 

Many LCDs are based on active-matrix addressing, in which an active device circuit containing one or more TFTs is connected to each pixel. The TFT circuit at each pixel effectively acts as an individual electrical switch that provides the means to store display information on a storage capacitor for the entire frame time, such that the pixel can remain emitting during this entire time rather than for a small fraction of time, as is the case in passive addressing. 

Passive Matrix LCD The reahzation of high resolution displays, or even the more simple alphanumeric displays, requires the independent addressing of each pixel. Different matrix techniques have been established common characteristics are the rectangular... 

Bistability of a display material does not guarantee multiplexibility. Proper drive schemes must be designed in order to make multiplexed displays on a passive matrix. A good drive scheme should possess the properties of fast addressing speed, low drive voltage, no crosstalk, and a simple waveform. According to the number of phases in the addressing, there are three major types of drive scheme for the bistable TN (1) one-phase drive scheme, (2) two-phase drive scheme, and (3) three-phase drive schemes. 

The quasi-bookshelf orientations produced by AC-field treatment have been applied to passive matrix FLC displays. Rieger et al. reported that a quasi-bookshelf orientation induced by AC-field treatment showed a contrast ratio of 60 1 with a line-address time of 90 isec under the control of a 4-slot multiplexing addressing waveform with a bias of 4 1. They presented a 1.9" passive matrix FLC panel with 96 X 128 pixels that they had fabricated by using this method [8]. The specifications of their prototype FLC display are given in Table 6.1.2. T. Kitamura et al. also reported use of the AC-field treatment method to fabricate a passive matrix FLC display with 2000 x 2000 pixels [9]. The specifications of this display are summarized inThble 6.1.3. 

Hartmann investigated the texture-change phenomena and reported that texture III can be used to implement analogue grey scale switching, in which the ratio of black and white domains is controlled by the addressing waveform [6]. Hartmann then applied the texture HI state to a passive matrix FLC display (Thble 6.1.4). 

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