The secret lies in the crystals. The same ones which lend their name to Liquid Crystal Display (LCD) technology. The method by which they’re applied, and in the process aligned with each other, remains a modern day miracle.
Dr Harry Walton, Director of Optical Imaging and Display Systems at Sharp Laboratories of Europe describes the construction of an LCD screen as “a sandwich”, comprised of two layers of glass.
“They’re your slices of bread,” he explains, “and in between you’ve got your filling, which is a layer of liquid crystal.”
It’s that liquid crystal filling which is so mesmerising. “It’s a sort of soup of tiny matchsticks” says Dr Walton. “You need to get those matchsticks to line up. You need to tell them which way to point.”
But how to get them pointing the same way is a question still dogging researchers today. There are a couple of methods which work just fine, and make the TV in your lounge work perfectly. The problem is, nobody really understands why.
Many manufacturers, including Sharp, use a brushing technique applied to a thin layer of polymer coated on top of the glass. The polymer, itself just a few atoms thick, is rubbed by a fast-moving velvet cloth before the liquid crystal is placed on top.
The crystals inside the fluid align themselves, and make the LCD screen work. You’d be forgiven for thinking that static electricity, or tiny grooves in the polymer were the cause, but Dr Walton says at the moment, they’re just theories amongst the scientific community.
“Another theory is that maybe we locally melt the polymer as we rub it, and tease the polymer chains out,” he adds. “But no-one really knows.”
In the meantime, Sharp appears to have proved that the orientation of liquid crystals isn’t due to any physical contact at all.
“Working in clean rooms, as we do,” says Dr Walton, “rubbing things with bits of cloth is a necessary evil. It generates dust, so we don’t really like doing it. That’s one of the reasons that Sharp has moved on from traditional rubbing in some of its production lines, and developed a process called UV2A.”
“Instead of using a cloth for rubbing, we actually ‘rub’ with light. How it’s done is very confidential within the company, but it’s a process that Sharp has developed to make its displays even better.”
It seems that whether light or cloth is used to align those tricky crystals at the heart of your big screen TV, there’s a mystery to behold. Something to chew over next time you sit down to watch Eastenders. No matter how obvious the plot, there’s magic inside each and every one of those LCD pixels.