Shades of Gray, The Curious History of LCDs

Prof. George Gray

Today is the 40th anniversary of an innovation in chemistry that has had, arguably, a greater impact on our society than any of the Chemistry Nobel Prize winning achievements in the past 40 year. But the man responsible, George Gray, is only known in select chemistry circles (apart from maybe a few travellers boarding a train traveling between London and Hull that bears his name). Yet you are almost certainly reading this blog on a device that owes its existence to Gray. For he and his small team, of just two post-docs, developed the first liquid crystals that were viable in liquid-crystal displays (LCDs). Forty years ago today his work was published, triggering a multi-billion dollar industry and making today’s abundance of flat screen devices possible.

The breakthrough that emerged from Gray’s small group was the synthesis of 4-Cyano-4′-pentylbiphenyl (5CB). It had a nematic liquid crystalline phase between 22C and 35C which made it the first material that could form the bases of viable LCDs.*

4-Cyano-4′-pentylbiphenyl

Just like so many great innovations getting to this point had been far from easy, largely because there was little appetite for funding research on molecules that, at the time, had no clear applications. Turning liquid-crystals from curiosities into the ubiquitous technologies that they are today required both a burning need for new displays and the foresight of one of the more colourful government ministers.

Enter John Stonehouse, Minister of State for Technology under the UK Prime Minister Harold Wilson. Stonehouse wanted a technology capable of producing flat screen colour displays (a good 30 years before LCD TVs became the norm) with the aim of replacing cathode ray tubes that were costing the Ministry of Defence colossal sums (more than the development costs of Concorde) in royalties. So in 1968 he set up a working group consisting of military brass, civil servants and scientists to find a suitable replacement technology. The way the contracts were distributed is a far cry from how things are done today. The story goes that at one of the group’s meetings liquid-crystals were proposed as a candidate. But the key speaker was unable to answer a question about why light from the projector generated such curious patterns as it reflected off the vials of liquid-crystals. There followed an embarrassingly long silence before a voice piped up from the back of the room exclaiming “I wonder if I can help”. That voice was George Gray’s and come the end of the meeting he and his team of chemists at the University of Hull were awarded the contract to deliver room temperature liquid-crystals.  That they did and the results were patented and published by 1973 with the first LCDs in commercial devices the following year. (Cyril Hilsum was chairing the session and he was recently filmed recounting his memory of the  meeting and the development of LCDs. You can watch it here  http://youtu.be/AaB902_ds-g?t=34m3s )  

At one time the molecules that Gray invented accounted for over 90% of all the liquid-crystals in the world’s calculators, digital watches and LCD clocks. So what became of the money that flowed in via the patents? Well the Ministry of Defence owned most of the intellectual property and made a tidy sum which offset the money they were still paying for cathode ray tubes.  Meanwhile the University of Hull, like most UK academic institutions at the time, didn’t think it was its place to own intellectual property, so the remainder of the royalties went to Gray and his team. But Hull wasn’t left completely out of pocket, the MOD continued to invest in LCD research in Hull until the patents ran out in 1992.

As for Stonehouse he may well have been blessed with the foresight to back LCDs, but he wasn’t so hot with his own businesses. Shortly after the first LCD devices were being manufactured his clothes were found piled on a beach in Florida with no sign of his body. He had apparently committed suicide after a series of disastrous business ventures. In reality he had faked his own death and was winging his way to Australia to start a new life with his mistress. The law caught up with him, briefly mistook him for Lord Lucan before sentencing him to several years in gaol. As if that wasn’t enough intrigue for one man he also turned out to be a Czech spy!

References:

1)  Gray, K.J. Harrison, J.A. Nash. New Family of Nematic Liquid Crystals for Displays, Electronic letters. 9:6. pp 130-131, 1973

2)   Hirohisa Kawamoto, The History of Liquid-Crystal Displays. PROCEEDINGS OF THE IEEE, 90: 4. pp 460-500.  2002

Footnote:

* A working range of 22 to 35C was not, of course, anywhere near sufficient for saleable LCD display.  That came about via a series of  mixtures of 5CB with new cyanobiphenyls which eventually settled on a quaternary mixture known as E7.

Composition of E7. From ‘The History of Liquid Crystal Displays’

 

 

Originally posted (as a slightly different version) in the Guardian.

One Comment

  1. Just reading this now, but thanks for the history lesson. Always cool to know the origins of some of our modern technologies (and especially the ones that start with chemists)