LCDs – Windows on the Digital World

Notebooks light as a feather, brilliant PC monitors, multimedia telephones, flat-screen TVs — high performance liquid crystal displays (LCDs) are all around us. And while the very first LCDs seem primitive compared to today’s technology, their introduction to the mass market launched a technological evolution that revolutionised the way we view images. That’s because they provided the first-ever compact, long-lasting displays with low power consumption for digital devices.

The media revolution began in light-gray/black tones back in 1973, when new types of liquid crystal displays were first installed in watches and calculators. These devices represented the first generation of a technology that has dramatically changed our perception of digital content. After all, LCD technology is the foundation for the popularisation of mobile electronic media and communications equipment; LCDs have now become the interface between humans and machines.

Merck, an international leader in liquid crystal technology, has been at the centre of these developments — from the first LCD watch displays to today’s large-format thin-film transistor screens. This will remain so in the future, when we will see even broader viewing angles and faster reaction times, both of which will improve image perception. That’s because the larger the viewing angle, the more people can sit next to each other, allowing even those off to the side a normal view of the screen. At the same time, faster reaction times will result in much sharper images, even if such images are in dynamic motion, as is typically the case with computer games.

Merck has been conducting intensive research into liquid crystal applications since 1968 and, in the meantime, the company now holds more than 2,500 relevant patents. Merck has also cooperated with equipment manufacturers to bring numerous new processes to the series production stage. For example, anyone who just has to have a new smartphone whose screen can both show videos and act as an input device for text messages is probably benefiting from the ideas and innovations generated in Darmstadt, the home of Merck.

LCDs have long since replaced the cathode ray tube — with its roots extending way back into the analogue age — as the dominant display technology. In fact, in 2008, worldwide sales of LCD televisions outnumbered those of TVs with tubes and plasma flat screens for the first time ever.
   
What’s more, it is only because of liquid crystal technology that monitors, projectors, and touchscreens have become the most important interface between the human being as a visual animal and the computer as a machine. The flat, sharp, and colourful displays have become a normal part of our everyday lives within the space of just a few years — and today’s 21st century users hardly even notice that they’re there.

A look back reveals just how much progress has been made in this field. For example, the first-generation portable computers from the early 1980s were either boxes with small-format cathode ray tubes (CRTs), or else they anticipated the clamshell design of later notebooks — but showed their information on an electroluminescent display (ELD). Although the latter were flat, they also consumed a lot of energy. The LCD monitors available at the time weren’t yet very convincing either, as these tiny displays couldn’t show more than just a few lines of code.

Energy-saving LCD displays that used the twisted nematic liquid crystals (TN) developed in 1971 then began gaining dominance as digital displays in relatively simple devices such as digital watches and calculators. TN LCDs use helical liquid crystal structures that twist through 90 degrees. These crystals are sandwiched between two thin glass plates that have polarisation filters oriented at right angles to one another. TNs let through light in their resting state. However, applying voltage to them causes the liquid crystals to arrange themselves parallel to the electric field, which causes the cells to turn dark.