Friday, May 25, 2018

So You Think You Know Liquid Crystals....


Let’s play a game. Tell me how you would finish this sentence: “Liquid-Crystal Display Technology is…” 

Amazing – OK, but can you be more specific?

Great for TVs, phones, tablets, computer displays, etc. – Sure is! And just about every other application you can name as well. During the opening comments for the LCD 50th anniversary technical session at Display Week 2018, SID President Helge Seetzen commented that LCD technology has paved the way for the ubiquitous penetration of displays into virtually every possible application.  

Complicated – Yup. Over the last 50 years, dozens of different areas of science and technology had to converge to make what we have today. While most innovations build on a previous foundation, LCDs are somewhat unique in that developers had to mostly build their own foundations as the technology evolved from those first demonstrations of the electro-optic effect of dynamic-scattering liquid crystal by inventor George Heilmeier at RCA in 1968.

Rocket science? – No, maybe not that complicated, but let’s come back to that.

Based on vegetables – Huh? What? OK, well actually yes that’s true - carrots specifically. While LCD technology is now 50 years old, the first discovery of the materials now classified as “liquid crystals” dates back 130 years to 1888, when scientists at Merck in Germany first identified a compound extracted from carrots that exhibited physical properties not yet seen. Merck first started offering liquid-crystal materials for scientific study at the turn of the 20th century but it wasn’t until the 1960s that people started looking at them for this type of application.

Resilient – For sure! Over the last 50 years, countless development efforts have evolved the technology from its simple roots in passive-matrix monochrome twisted-nematic mode text displays. During the 1970s and 1980s, critical advancements such as rubbing to establish alignment, passive- and active-matrix addressing to control pixel arrays, and super-twist and dual-domain modes all helped improve viewing angles and contrast to a point where the technology really began to show promise. Along the way, amorphous-silicon and poly-silicon technologies were also developed to support the practical fabrication of TFTs. By the 1990s LCDs were starting to find practical application in places such as avionics and eventually they became a critical component in the evolution of laptop computers. But there were still many performance limitations to overcome, such as response time, color gamut, viewing angle, etc.

While LCDs performed well and were crucial to laptops, CRTs were well established as the performance standard for televisions, and a lot more development was needed to make large-screen LCDs that could compete. In the next decade, countless innovations such as overdrive, faster switching and higher frame rates, additional LCD modes such as VA and IPS, copper electrodes, dual-side drive, and many more all converged to displace CRTs, and achieve never-before-seen television screen sizes. Along the way came the iPhone and the enabling of a whole new class of consumer devices built around the LCD screen.  At each milestone, a new threshold of performance has been challenged, and the industry continues to evolve today with quantum-dot backlights, glass-based light guides, 4K and 8K resolutions, stereoscopic viewing, and many more innovations that were shown in Display Week’s 2018 exhibition.

Unlikely – Maybe. Consider what might have happened if the early pioneers of LCD technology had foreseen all the development work that lay ahead and problems that had to be solved from 1968 to today. Would they have taken it on? Of course they would have! As I listened during the sessions from pioneers including Martin Schadt, Fan Lou, Koji Suzuki, Kenji Okaoto, Injae Chung, Jon Souk, Mark Verrall, Terry Scheffer, and William Doane, I could still hear the passion in their voices and the love of the challenge they had taken part in.

I wonder what their business leaders might have said if they had all sat down in one room around 1990 and assessed what was ahead of them: Investments measured in the tens of billions of dollars to develop the technical and manufacturing infrastructure. A market place that almost immediately oscillated between over and under-supply and invoked commodity-style pricing pressures. Products with unique capabilities but limited to certain key markets. Consistent and relentless competitive pressure at every turn. Would they have decided to move forward? Certainly several early entrants did not choose to move forward, and others took up the challenge along the way and became dominant players. But, looking across the entire span of 50 years, that would have been a big risk to take for anyone and a great test of vision and courage! Congratulations and much respect goes to those who did see this future and fought hard for it.

So is it rocket science? In some ways it certainly feels like it. While LCDs are not literally as complicated as the space shuttle, their development has employed what might be a similar order of magnitude of engineers and scientists, and probably crosses the boundary to almost as many science and technology disciplines. It has clearly occupied a similar timespan in human history as modern space programs, and LCDs have literally travelled beyond earth’s orbit and might even be on rovers on other planets today.

I just want to say what a privilege it was to hear these great speakers talk so passionately about their work and to attend the wonderful program so well organized here at Display Week 2018 -- Stephen Atwood

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