January 25, 2008

LCD – Liquid Crystal Display – Technology Overview


The twisted nematic liquid crystal molecules of an LCD display are sandwiched between two sheets of glass with electrodes. Vertical and horizontal polarizing filters are positioned either side of this sandwich. The rod like twisted nematic liquid molecules are aligned to match the orientation of the vertical and horizontal filters on either side allowing light to pass through one filter, rotate and pass out the opposite filter.


LCD Pixel Structure

The control electrodes are aligned in a matrix to provide an array of pixels consisting of three individually controlled sub-pixels with either a red, green or blue filter positioned in front. The level of voltage applied across the electrodes (and liquid crystal) is proportional to how much the naturally twisted liquid crystal will untwist and attenuate the light flow due to the difference in the polarizing filter orientations. A greyscale can thus be produced. The color gamut of each pixel is produced by the combination of color graduations from the color sub-pixels. The matrix of pixels for each display matches one of the standard resolutions (number of horizontal and vertical pixels).

Twisted Neumatic (TN) LCD displays are the most common however there are variations which have been designed to compensate for its limited viewing angles and limited color gamut.

  • In-Plane Switching (IPS) has the two electrodes for each pixel on the same glass plate parallel to each other. This orientation offers no restriction to the angle at which light leaves a pixel improving the viewing angle and color reproduction in comparison to TN. Recent improvements in response times, contrast ratios and production costs have IPS displays poised for greater market penetration. Find out the details in our IPS vs TN LCD technology guide.
  • Multi-Domain Vertical Alignment (MVA) has the liquid crystals that are perpendicular to the glass plates which have pyramid protrusions for liquid crystal rotation control. This approach gives wider viewing angles, a higher contrast ratio and faster response times. A major drawback is a reduction in brightness.
  • Patterned Vertical Alignment (PVA) is a variation of MVA which gives higher contrast ratios.

0 Comments »

No comments so far.

RSS feed for comments on this post. TrackBack URI

Please add your comments to the post topic

Comment spam protected by SpamBam







Expert Advice

ISFccc Calibration

1080p vs 720p or Full HD vs HD

HDTV as a PC Monitor

Native 24p Playback vs 3:2 Pulldown

Timeline for 3D Without Glasses

Tips for Longer Lasting Projector Lamps

Myth of Plasma Burn-in


Best of Reviews

Best Plasma HDTV

Best LED LCD HDTV

Buy Plasma for Best 3D

Best Pico Projector


Disruptive Display Technologies

Pixtronix LCD 2.0

Quantum Dot LCD

LED Pico Projectors

Wireless HD

Sharp Memory LCD

Electrofluidic Display







Technology Comparisons

What is 3D Crosstalk

How LCD Local Dimming Works

How an LCD Display Works

How a Plasma Display Works

How Digital Light Processing (DLP) Works


Technology Comparisons

Passive Polarisation vs Active Shutter 3D

In Plane Switching (IPS) vs Twisted Nematic (TN) LCD

120Hz 240Hz and 240Hz Effect LCD Anti Blur Technologies Compared

Advantages of LED over Conventional LCD Backlighting

Lens Shift vs Digital Keystone Correction



GPS Navigation Reviews


Media Tablet Tek


Media Tablet eReader Reviews
Moorestown Atom Processor
Samsung Galaxy Tab vs iPad
E Ink Pearl Display





  © 2006-2012 - all rights reserved. |  about |  links |  terms of use |  privacy
Company names, tradenames, trademarks and similar used are the property of their respective owners