Until not long time ago, the most common ways of entertainment were reading books or listening to music. Then by mid of 20th century television started to gain in popularity and watching a movie at home has become very much a new common habit to enjoy our leisure time. However the first TV sets were made for black and white rendering. It took a while until color TV screens started to furnish houses in early 1980s. For years Black &White screens had better image quality versus color version. However during 1980s and 1990s as result of continuous development in image quality, color screens quickly started to replace black & white screens. After the year 2000 color screens clearly started to dominate everything that creates visual impact. This tech development has revolutionized the entertainment industry. This is only possible because of Liquid Crystals. But what is this stuff? What makes them so special that we are so addicted to them?. Let’s find out in this article.
HOW LIQUID CRYSTALS CREATE COLOR?
We all know that if you take yellow paint and mix it with blue, our eyes interpret that mixture as green, similarly, if you take red paint and add blue, you get purple. Hence the Colour Theory shows that you can make any particular colours by mixing together combination of primary colours.
For example in the printing industry, cyan (C) , magenta (M) and yellow (Y) are generally used as primary colors with the addition of black (K) liquid to control contrast. This is also how inkjet printers work and why you see the abbreviation CMYK on the side of printer cartridges. These colours are printed on the page by your printer, dot by dot, and it´s our eyes and visual system that integrate them into a coherent colour. This phenomenon is not a recent discovery, we’ve known that the eye can be fooled this way for a long time. Even Isaac Newton took note of this manipulation in the 17th century and it was used as a painting technique by the Pointillists in the 19th century.
In case of paintings the main advantage is that the blobs of pigments remain physically unmixed and so their brightness and luminosity can be controlled to create the effect you want. As predicted by colour theory, it´s possible to make any colour by mixing paints this way as long as the dots are small and placed close together. But changing the colour once you’ve made them is another story. You´d have to physically change the ratios of pigments on the canvas. Which means you would have to remove some dots and add others. Unless, of course, you’ve found a way to put down dots with every possible combination of colours. In the case of Liquid Crystals the same color theory applies, except that instead of paint/ink the principal working element is: The Light.
The most powerful property of LCs is their ability to create strong dipoles within their molecular structure making them to respond whenever an electric field is applied. When light travels through a liquid crystal, subtle changes occur: the polarization changes. To make sense of this, think about light as a wave: a wave of oscillating electric and magnetic fields.
Alright, but then which direction do they oscillate in? Up and down?, side to side? or left and right? Standard light from the sun oscillates in all of these directions. But if it bounces off a smooth surface, the surface will encourage the oscillations to move in certain directions, and suppress others, depending on which ones it´s aligned with. Thus the rebounding light will contain some oscillations and not others. This is called polarized light. It´s not just surfaces that do this to light. Some transparent materials will change the polarization of light, too; polarized sunglasses, for instance.
The lenses of polarized sunglasses only let one direction of oscillation through. This obviously reduces the intensity of the light reaching your eyes, which is why you see the world as darker. They´re especially useful at the beach, not just because they shade your eyes, but because the glare coming off the surface of a smooth sea is also polarized, and the lenses are designed to block it out. Fishermen use polarized sunglasses to help them see underwater more easily, and photographers use polarized lenses for the same reason – to cut the glare
If you put a lens from your polarized sunglasses on the surface of a crystal, the light coming out of the liquid crystal will appear bright if its polarization is aligned with the lens, but otherwise it will appear dark. But here is the neat trick: if you switch the structure of the liquid crystal its polarization also changes. So at the flick of a switch, you can turn the light on and off. Suddenly, you have a device that is capable of giving out white light, and then none, and then going back to white again, as fast as you can electronically switch the liquid-crystal structure – that’s the makings of a black-and-white screen.
Similar with primary ink pigments used for printing known as dots of color in case of LCs the dots are called: pixels. Each pixel has 3 coloured light filters that let 3 primary colours through. For displays these are red (R) , green (G) and Blue (B)- hence the abbreviation RGB. If they are all emitted equally, then the pixel appears white, even though it´s made up of 3 separate colours. You can see this for yourself if you put a small drop of water on your phone and look through it on to the screen. The water behaves as a magnifying glass which allows you to see the sets of 3 different pixels: red, green and blue.
This is essentially how liquid-crystal colour displays work, whether they´re on your phone, your TV or encased in the back of the seat in front of you on the plane.
All these, may sound simple, but it took decades to achieve. It was an Austrian botanist by the name of Friedrich Reinitzer who first categorized the weird behavior of liquids crystals in 1888, just two years before Oscar Wilde wrote The Picture of Dorian Gray. While many scientists studied them over the course of the next 18 years, no one could really find a use for them.
It wasn´t until 1972, when the Hamilton Watch Company launched the first digital watch, called the Pulsar Time Computer, that liquid crystals found their moment. The watch looked great, unlike any other watch that had come before it, and it cost more than the average car. People who bought it thought they were buying the future – and they were right: digital technology was coming, and this was the first mass-market item in what would become a trillion-dollar industry.
The Pulsar Time Computer was made with LEDs – Light Emitting Diodes – which were themselves made from semiconductor crystals that emit red light in response to an electric current. They looked great especially on a black background, and the rich and famous went craze for them – even James Bond wore one in the 1973 film Live and Let Die. The drawback of LEDs at that time, though, was their high energy consumption; those first digital watchers had very short battery lives. In order to satisfy the new-found sensational demand for digital watches, there would need to be a more energy-efficient screen technology, hence Liquid Crystals could perhaps be just what´s needed.
Suddenly, after decades of being a lab curiosity, liquid crystals had their use. They quickly dominated the digital-watch market because the electric power required to switch a liquid-crystal pixel from white to black is absolutely minuscule.They were cheap too – so cheap that manufacturers started making the whole display screen out of liquid crystals – this is the Grey screen you see on a digital watch. The watch electronically switches certain areas of the Grey liquid crystal to block polarized light which creates black. This allows the watch to show changing numbers, so you can view the time, or date, or anything else that can be conveyed in this small, digital format.
One of my strongest memories from childhood in the late 1980s is the insane jealousy I felt when my best friend came back to school after the holidays with the new Casio digital watch and calculator. I was ridiculously impressed as he nonchalantly pressed the tiny little buttons which beeped happily at him. Of course, I see now it´s kind of dumb – who really wants a tiny calculator? But still, at the time, I was completely captivated. It was the beginning of my addiction to gadgets. Even though digital watches have lost their cool, they’ve been replaced by a seemingly never-ending parade of other gadgets, not least of which have been mobile phones, which are still using liquid-crystal displays. It may seem surprising but it is the same basic technology used in a digital watch that has also yielded the modern smartphone screen, capable of displaying color video. Actually today I do own a Samsung SmartWatch with touchscreen which is exactly a advanced version of a classical digital watch. This brings us right back to oil paintings, and the puzzle of creating the moving painting depicted in the novel The Picture of Dorian Gray.
HOW LIQUID CRYSTALS CREATE MOVING IMAGES?
Just as the masters of oil painting had to work out how to bring darkness and shadow into their work by mixing colours and inventing a colour theory for perception, so are today´s liquid-crystal displays engineers and scientists pushing the boundaries of colour display with moving images. And just as in the Renaissance, when oil painting battled it out with other techniques, like fresco and egg tempera, so these days do Liquid-Crystal Displays (LCDs) compete with Organic Light-Emitting Diodes (OLEDs).
This battle which is currently being played out it ever new generation of TVs, tablets and smartphones, has its own arcane language. LCDs, you might be told by an online article, can´t show deep blacks because the polarizers that keep light from coming through during a dark scene in a movie aren’t 100% effective; you end up with greys. The screenplays for Sci-Fi and Fantasy movies are not only based on our imagination, the stories behind have seeds of truth.
Let’s take for example the SpiderMan movies: in reality some spiders can detect polarized light, and when I watched this movie I wondered if this could be part of Spider-Man´s ability to react quickly to danger, his so-called ´spider-sense´. In the film he’d just narrowly escaped being captured by Doctor Octopus with an uncanny, split-second decision that allowed him to evade the villain´s tentacles. The special effects were indeed amazing, but these are actually based on real facts, there are spider species that can indeed detect polarized light. Liquid Crystals change the polarization of light – that´s how the image of Spider-Man was being conjured up in the screen in front of me when I watched the movie.
Similarly, because of the way colour is created in LCDs, the absolute brightness of some hues suffers. Hence the issue with the blinds in the cabin on a plane, and not wanting to have sunlight reflecting off the screen making things worse. Nevertheless, the displays have got better and better thanks to great innovations that ultimately aren’t so different from layering oil paint. For example the addition of an active-matrix layer allows some of the pixels to be switched independently from others. Thus some parts of the image can be given higher contrast than others – instead of having to set the contrast for the whole image. This is useful for scenes of a movie that are partially lit. It is all done automatically of course, with transistor technology – that´s what the ´active´ means in ´active matrix´. Engineers have also learnt to improve the way the image changes depending on your viewing angle. It used to be that you couldn’t see the screen very well at certain angles, but now a ´diffuser layer´ is incorporated, which spreads the light out as it leaves the screen.
In comparison, the technology of OLEDs, which are the successors of the red-light-emitting diodes of the original digital watch, the Pulsar Time Computer, are now energy-efficient. They also have a much larger palette of colours, and near-perfect viewing angles. But, despite being much more expensive than LCDs, they´re still not yet as bright.
LCDs may not be perfect, but they are essentially the dynamic canvas that Oscar Wilde dreamed of. It´s now possible to have a portrait of yourself on display in your hall (or your attic) that updates daily. When liquid-crystal displays became really cheap a few years ago, people started giving them to one another as presents in the form of dynamic photo frames. But these didn’t end up being that popular. In fact people hated them, just as Dorian Gray loathed his dynamic portrait. I´m convinced it wasn’t the quality of the image that they hated – plenty of people love looking at themselves on their liquid-crystal smartphone display – but rather, something about the very nature of these displays. They´re impostors, something fluid, magical and dreamlike pretending to be a solid, dependable and real photograph of a moment frozen in time.
When applied to television in the form of flat-panel TVs, that same technology has been hugely popular. Switching the colour of the pixels in a coordinated manner allows TV screens to display moving pictures. They´re why we can see actors talking, gesturing and making different facial expressions, and in the case of the SpiderMan movie, leaping from building to building, saving the world from evil. When I watched this movie, even though I knew what I was watching wasn’t real, that it was just a collection of primary-colour pixels flashing along to an accompanying soundtrack, it still stimulated me, both intellectually and emotionally, completely absorbing me in the story.
But here is the thing I find really difficult to understand. If I compare the experience of watching this film on a plane with standing in an art gallery viewing a masterpiece such as Titian´s Resurrection, I know which one is more likely to move me. It´s the film, I´m afraid. I´m not proud of this. I know that Titian´s paintings are great art and superhero movies played on a 10-inch display on the back side of a seat in a plane, are not. Why am I so shallow? Could it be that at 12.000 meter altitude I lose all taste in art? Or it is something to do with the heightened emotional state of flying?
Well.. to me this is clearly because Liquid Crystals are able to create a strongly visually impact of moving images, hence making me feeling absorbed into the action happening in front of my eyes. LC don’t just create a static experience, they provide you a dynamic experience so that you for sure want to repeat.
Computer Aided Design & The 118 Elements 
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