A twisted discovery
Winner of the European Inventor Award 2013 in the category Lifetime achievement
Martin Schadt, inventor of the liquid crystal display (LCD)
Behind the bright colours and crisp images of today's flat-screen TVs lies a scientific principle that was once regarded with incredulity a simply unthinkable phenomenon. Today we know it as the pixel.
It is the life’s work of Martin Schadt, a Swiss scientist who almost single-handedly helped develop liquid crystals. This unique substance, which is neither solid nor liquid, proved to have a far-reaching impact on the electronics industry.
Flat screens, high revenues
With every passing year, TV screens seem to get wider and flatter, their colours more brilliant. Flat-panel displays with thousands of miniscule pixels have replaced the bulky television sets that were once a ubiquitous fixture in every middle-class living room.
More commonly known as Liquid Crystal Displays, their discovery forever changed how we watch and appreciate motion pictures. Integrating LCDs into consumer products has given rise to an industry with worldwide revenues of some $100 billion in 2012.
Behind this state-of-the-art gadgetry lies the innovation of one man, a Swiss scientist who demonstrated a knack for experimentation even as a teenager in the rural village of Liestal, near Basel.
Using parts he salvaged from old scrap radios, 16-year-old Martin Schadt made a hobby of piecing together rudimentary short-wave transmitters and disrupting local radio reception, irking his neighbours.
University was not a prospect many people entertained in rural Switzerland in the 1950s; young Schadt satisfied his scientific curiosity with a four-year apprenticeship as an electrician in Basel before attending night classes and pursuing a Master’s degree in experimental physics.
“I’m a very curious person and I’m interested in how things work; this was the reason I studied physics,” Schadt said.
Eventually, Schadt’s interest was piqued by the study of organic semiconductors – a highly complex and experiment-driven field that satisfied the appetite for empirical research, testing and examination he had since childhood.
“I was always interested in multi-disciplinary research… You just have many more opportunities to invent new things,” Schadt said.
After completing his PhD thesis in 1967 and attending a postdoctoral fellowship at the National Research Council in Ottawa, Canada, he joined the Swiss watch company Omega in 1970 to aid with the development of atomic time standards.
It was then that he became aware of a research project at the pharmaceutical company F. Hoffmann-La Roche in Basel examining liquid crystals, substances whose molecular structure is neither completely aligned (like a solid) nor in total disarray (like a liquid).
The project involved a combination of physics, electro-optics and organic materials – perfect for a man whose scientific interests spanned several disciplines. Schadt quickly proved himself a savvy innovator in the field.
Schadt’s big breakthrough came when he began testing the idea of a colleague named Wolfgang Helfrich, who had hypothesised that the long helical axis of liquid-crystal molecule could be ‘unwound’, causing an optical change.
“Helfrich had the idea and I designed and implemented the experiments…” said Schadt. “Within a short time we developed new liquid crystals which were able to realise this polarization effect.”
A ‘shocking’ innovation
Schadt and his team noticed that when jolted with electricity, the molecule’s spiral structure untwisted partially, blocking light and causing the crystal to appear opaque.
By sandwiching a layer of liquid crystals between two plastic plates, Schadt discovered that he could use the opaque liquid crystals to create visible shapes, such as the dark numerals found on calculator screens today.
“At the end of my PhD, I was a bit frustrated,” Schadt said. “I did not believe that it would be possible to use the technology to manufacture displays, working at low volt levels.”
But Schadt eventually discovered that it wasn’t necessary for the electric field to fully unwind the liquid crystal helix, and that a few volts were sufficient to interrupt light transmission. This meant LCDs could also be operated with ordinary batteries, boosting their usefulness and greatly expanding the number of fields where they could be applied.
Doing the twist
His discovery became known as the twisted nematic (TN) effect, and it proved to be a game changer for the electronics industry, particularly because it made possible the radically improved TV screens of today.
Thanks to Schadt’s innovation, Roche was able to establish itself as a major supplier of liquid crystals for the LCD-industry, which today sees annual revenues of about $100 billion. Until 1994, Roche was the major technology provider in the world for LCD producers.
Roche’s business model focused on the production of materials for prototypes and then licensing the patents to customers such as big LCD manufacturers and optical film companies.
Race against time
However, securing a patent for TN proved turbulent, and Schadt learned just how difficult obtaining adequate intellectual property rights for new ideas can be without significant resources.
While Schadt worked on his liquid crystals at the Roche lab, a researcher from Kent State University in Ohio visited him. An expert in the field himself, the man quickly recognised the commercial potential of Schadt’s discovery and relayed what he had seen back to a similar company in the United States.
After learning of the leak, Schadt and his company rushed to file a patent just two weeks later, on December 4, 1970. The man at the American company also filed a patent application for the identical invention in the United States, mere months after the meeting.
Luckily for Schadt, the American company was in some financial trouble and was eventually forced to sell its US patent – to Roche, who had deployed an army of legal, patent and scientific experts from Basel to the US patent offices in Washington, D.C.
In 2012, electronics giants such as Sharp, Sony, Panasonic and Philips manufactured more than 40 million LCD TVs using Schadt’s technology – TVs which found their way into consumers’ homes, forever changing the look and feel of millions of middle-class living rooms.
As for Schadt, he stayed at the helm of Roche’s liquid crystal research division until 1994, when the division split off into its own company called Rolic Ltd. In 2010, Rolic supplied nearly 15 million LCD displays worldwide. Schadt continued as CEO and board member at Rolic until retiring in October 2002.
Throughout his illustrious career, Schadt has received numerous awards. Today, he holds more than 110 patents – each filed in at least 10 countries. He has published 174 scientific papers as well as four book chapters.
Now 74, Schadt still actively advises research organisations and governmental agencies. His legacy, however, will forever lie in the minuscule pixels of flat-screen TVs, computer monitors or digital camera displays – quite an advance from the ham radios of his mischievous youth.
How it works
Liquid crystals represent a state of matter that is neither a liquid nor a solid. Their molecules can be manipulated with electricity to alter the way they transmit polarised light, making them appear either transparent or opaque.
All devices with liquid crystal displays are constructed in a similar manner. A thin polymeric layer of liquid crystals is sandwiched between two flat glass plates, which are coated with a grid made of perpendicular rows of electrodes. Individual sections of the grid are known as ‘pixels’.
The electrodes themselves are coated with ‘alignment layers’ that polarise (change the planar orientation of) any light that passes through. These layers act as filters that block all light rays that lack a certain orientation.
Light that passes through the first filter reaches the liquid crystals, which have a molecular helical structure that is twisted like a corkscrew standing on end. If the crystals are left alone, the light will spiral down their corkscrew-like shapes, thus polarising again by turning its orientation 90 degrees. The rays then pass through the second (horizontal) filter unhindered, and the crystal appears transparent.
Applying an electrical charge to the crystals unwinds them. When unwound, the crystals’ molecular structure won’t turn the light rays at all, and the rays will be blocked by the second alignment filter. This makes the crystals appear opaque.
By applying charges to various pixels on the electrical grid – thereby activating only some of the crystals – shapes appear, such as the numerals on a calculator screen.
The discovery of liquid crystals
It all started in 1888 when an Austrian botanist named Friedrich Reinitzer began melting a cholesterol-like substance and made a surprising discovery: the material had two boiling points. At 145.5°C the solid crystal softened into a cloudy liquid and stayed that way until heated to 178.5°C, when matter became completely transparent.
Baffled by his discovery, Reinitzer consulted the German physicist Otto Lehmann, an expert in crystal optics. Lehmann confirmed that the transparent substance was indeed a liquid – and he was convinced that the cloudy mass enjoyed never-before-seen properties. He dubbed it ‘liquid crystal’ after its unique quality of hovering between liquid and solid.
The duo’s conclusions withstood the critical review of their peers and had introduced a new understanding of material physics to scientific circles by the 1930s. No longer did scientists acknowledge only three states of matter: They now know that there are thousands of substances that exist in a number of intermediary or other distinct states.