LCD – For the Novice and the Expert

Basic LCD exploration

As LCD technology progressed, more and more complex systems were created. The Passive LCD display became the standard LCD during the early 90’s. The fundamental flaw with passive displays was that they could only address the three subpixels as a whole, rather than each individual subpixel.

© Samsung

Thus, TFT displays were born. Born from the same principals of passive displays, active displays went a step further and began to control the degree of how much each subpixel of the liquid crystals were twisted. As a result, the pixel as a whole could produce more than shades of color. Almost every LCD on the market today is capable of producing 256 shades from each sub-pixel. Because there are 3 sub-pixels, this means a typical pixel on a TFT LCD monitor is capable of producing 256 x 256 x 256 hues (16.7 million).

To take an example from today’s monitors, we can look back to our Samsung 172T and Hitachi CML174 reviews. The Samsung 172T produces 16.7M colors, or 256 shades per sub-pixel. The CML174 produces an advertised 262,000 colors and a lower response time, or 64 shades per sub-pixel. AUO, the OEM manufacturer for almost every 16ms response time LCD, sacrifices color hues in order to produce faster responses on the liquid crystal. More simply, there is less electronic modulation with the AUO substrate, and the sub-pixel crystals are able to be twisted faster.