Passive matrix addressingis anaddressing schemeused in earlyLCDs.This is a matrix addressing scheme meaning that onlym+ncontrol signals are required to address anm×ndisplay. Apixelin a passive matrix must maintain its state without active driving circuitry until it can be refreshed again.
Thesignalis divided into a row orselect signaland a column orvideo signal.The selectvoltagedetermines the row that is being addressed and allnpixels on a row are addressed simultaneously. Whenpixelson a row are being addressed, aVselpotential is applied, and all other rows are unselected with aVunselpotential. The video signal or column potential is then applied with a potential for eachmcolumns individually. An on-switched (lit)pixelcorresponds to aVon,an off-switched (unlit) corresponds to aVoffpotential.[1]
The potential acrosspixelat selected rowiand columnjis
and
for the unselected rows.[2]
This scheme has been expanded to define the limits of this type of addressing typical LCDs.[3][4]
Passive matrix addressed displays, such asferroelectric liquid crystal displays,do not need the switch component of an active matrix display, because they have built-inbistability.Technology forelectronic paperalso has a form of bistability. Displays with bistable pixel elements are addressed with a passive matrix addressing scheme, whereasTFT LCDdisplays are addressed usingactive addressing.
See also
editReferences
edit- ^Wild, Peter J."First-Hand Histories: Liquid Crystal Display Evolution - Swiss Contributions".Engineering and Technology History Wiki.ETHW.RetrievedJune 30,2017.
- ^P. M. Alt, P. PleshkoScanning limitations of liquid-crystal displays,IEEE Trans. Electron Devices, vol. ED-21, pp. 146–155, Feb. 1974.
- ^J. Nehring, A. R. Kmetz:Ultimate limits for matrix addressing of RMS-responding liquid-crystal displays.IEEE Transactions on Electron Devices. Vol. 26, issue 5, pp. 795–802, May 1979.
- ^T. N. Ruckmongathan, V. Arun, Babu Hemanth Kumar:Line-by-Line Addressing of RMS Responding Matrix Displays With Wavelets.Journal of Display Technology. Vol. 3, issue 4, pp. 413–420 December 2007.