Active matrix addressing

Kaneko E Active matrix addressed displays Handbook of Liquid Crystals Vol 2A. Low Molecular Weight Liquid Crystals led D Demus, J Goodby, G W Gray, H-W Speiss and V Vill (New York Wiley-VCH)... 

Figure 13-18. Diagram of a simple pixel circuit for active matrix addressing of an OLED array. For a color display of N lows and M columns, this circuit must be reproduced Ny.My.7t limes.

Active matrix addressing can also be used in printer heads [628] and linear sensor arrays [629]. a-Si H TFTs are used to address a linear array of output or input transducers, respectively. In the linear sensor array, u-Si H photodiodes are used. 

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. 

Figure 5.5 Twisted nematic materials for active matrix addressing.

For high information-content displays, active-matrix (AM) pixel addressing provides improved display performance and reduced power consumption. In active matrix addressing each individual pixel is controlled by one or more thin-film transistors (TFTs). To date, most AM OLED displays have used polysilicon TFTs as the active elements, because they can provide sufficient current at low voltages and acceptable device dimensions, and they are capable of integrated drive electronics... 

V. Active-Matrix-Addressed Liquid Crystal Displays. . 127... 

Direct, multiplex and active matrix addressing are the three electronic drive methods used to generate the appropriate voltage at a particular pixel of an LCD, see Figures 2.11-2.14. The size, shape and pattern of electrodes on LCD substrates are fashioned to be compatible with the chosen method of addressing. In directly addressed LCDs the desired pattern of pixel electrodes is created by etching on one surface. A non-pattemed back electrode on the second surface provides the electrical contact. LCDs with multiplexed addres-... 

Figure 2.16 Schematic representation of a high-information-content LCD with active matrix addressing provided by thin film transistors (TFTs)J ...

The requirement of a very high and constant resistivity over time of nematic mixtures for TN-LCDs with active matrix addressing meant that new liquid crystals which met this and the other specifications, such as low viscosity and high positive dielectric anisotropy, were needed. The nitriles used in nematic mixtures for TN-LCDs with direct or multiplex addressing were soon found to be unsuitable for TN-LCDs with active matrix addressing. The polar nature of the cyano group leads to the solvation of ions from some of the layers on the... 

OLEDs can be addressed in a similar fashion to LCDs, see Chapter 2, i.e. directly with segmented electrodes, see Figure 4.8, by multiplexed addressing with rows and columns of electrode strips, see Figure 4.9 and by active matrix addressing with one transistor at each pixel, see Figure 4.10. The major... 

Figure 4.10 Schematic representation some of the elements of a generalised multilayer organic light-emitting diode (OLED) with active matrix addressing using thin film transistors. The impermeable encapsulation is not shown.

---