Interview with Cyril Hilsum CBE

Cyril Hilsum was born in May 1925, in the East End of London where he lived until the outbreak of war. His father was a street trader. He has two brothers. He describes his childhood as poor but happy, he says: “I distinguished myself quite often by taking what toys we were given to pieces and trying to work out how they worked and then trying to assemble them, usually unsuccessfully.  I could say that that’s how I began my engineering life.”  He adds that he had the feeling that life had more to offer than the East End and that it was up to him to work hard to break away from it.

Cyril was a bright child. He learned to read by the age of three and says he was “probably was a bit of a nuisance at home” and so his parents arranged for him to go to elementary school at the age of three. He progressed through the infants and into primary school where he was promoted early, along with a friend, also a bright pupil, into the senior class. The class teacher, George Bennett, was a great influence on Cyril, allowing both of them to work at their own speed, ahead of the rest of the class.

Having successfully passed his 11plus, Cyril went to Raine’s grammar school in Stepney until the outbreak of war, when he was evacuated first to Brighton, and then to Camberley. In 1943 he finished his school education and won a scholarship to University College London, to study physics with subsidiary mathematics. However, because of the war UCL, like many universities, was evacuated, and Cyril spent most of his time in Bangor, North Wales. He adds: “We didn’t come back to London until the end of 1944, beginning of 1945.  It was an interesting time being at university, and of course, learning a lot of physics.”

As Cyril’s date of his birth meant that, though he had been allowed to go to university rather than be called up for National Service, after graduation Cyril was required to work either in a government defence research establishment, or in a company which was working on defence.  The decision on his future was made by a Selection Board in 1945. Although UCL wanted him to be their first post-war PhD student, the Board sent him to Fanum House, in Leicester Square, London, to work with the administrators of the UK Infra-red programme. Cyril kept up his studies in his spare time, studying advanced mathematics and crystallography courses at UCL.

It was at Fanum House that Cyril’s interest in infrared developed. He explains: “Fanum House was the administrative centre of several government research laboratories which were doing work on infrared devices for the forces. In Britain we were doing some quite advanced infrared research, particularly in the near-infrared, to make devices.”

Cyril was supposed to read all the reports being issued about the USA infra-red programme, and communicate important points to the UK teams. He adds: “I soon realised that this would probably not be appreciated, so I did the reading but not so much of the communication. However, I did get to know the people at the two main establishments; Haslemere and Teddington. Since I was reading all these reports, I did learn a great deal about infrared. I got very interested in infrared transmission through the atmosphere, which came in useful later on, and I wrote a very long report on the infrared transmission of the atmosphere.”

In 1947, Cyril was transferred to the infrared group at the Admiralty Research Laboratory in Teddington, where he also got to know researchers at the neighbouring National Physical Laboratory (NPL). It was here that he met and played chess with Alan Turing. He says: “I played him, and I don’t think his mind could have been completely on chess at the time because I was able to beat him. It’s one of my claims to fame; I beat Alan Turing at chess. I may say that I didn’t learn a great deal about what NPL were doing, but I did learn a bit from him and Fox, the head of the section, who later became a professor. They were doing some pretty advanced devices, particularly in memories and things, which has not always been fully appreciated. I have never thought that NPL makes enough of the fact that Alan Turing worked on computing there.  We know a lot about him being in Manchester but not so much about him being at Teddington where NPL was doing some pretty advanced work on computing for at least the ten years after 1945.”

In 1950, the Teddington team was consolidated with the infrared team in Baldock at the inter-service laboratory working on electronic devices, SERL.  In 1952/3 with the head of the combined group being promoted to a role in London, and his deputy having left to do a PhD, Cyril, at the age of 25, was promoted to run both the group and the infra-red programme for the Admiralty, which involved contract research at various companies. Cyril says: “Unlike the practice these days, nobody trained me in management, I just had to learn by making mistakes, and hopefully somebody pointing them out to me, because I never realised them myself.”

Cyril continued his personal research, and developed new infrared photocells based on indium antimonide. This led to a general interest in semiconductors. He says: “I also became interested in the idea for a new converter of thermal infrared radiation which one of the group had come up with, based on the absorption edge shifts in a material called amorphous selenium. I started doing a fundamental study of how thermal image converters worked, including transmission through the atmosphere.” While he was at Teddington, he had joined a group measuring infrared atmospheric transmission which published a paper in the Proceedings of the Royal Society.  Cyril wrote a series of papers on how the device worked, including absorption in metal films and transmission through the atmosphere.  This research and his published papers formed the basis of Cyril’s PhD which he did externally via UCL.

By the late Fifties it had been decided that the whole group at Baldock would move over to semiconductors generally, with Cyril still working on indium antimonide. In 1960, Cyril was invited to take over the leadership of the research on gallium arsenide when the two people leading it decided to move to other topics. He says: “This was quite lucky for me, because in fact the two people who had been responsible had actually solved most of the problems and more or less laid the basis for progress. I was able to benefit greatly by what they had done and could actually start the manufacture and use of gallium arsenide.”

Cyril adds: “We began to get known as really the home of high temperature semiconductors. We called our programme the Red Hot Transistor, which went down pretty well, though there was never actually any red hot transistor or anything other than a pretty warm transistor. It took a long time before we actually had any kind of transistor, and it certainly wasn’t that well known.”

During this period, Cyril was invited by Maurice Wilkes to visit Cambridge and take a look at their work on EDSAC. He says: “I remember going there and seeing a rather small room filled with systems that all were working off valves, and it was extremely hot. Maurice explained to me that it was a good computer while it was working, but essentially, one of the valves would break every three days, and this meant considerable interruption. He asked was there any possibility that we could actually make transistors that would solve his problems?  I pointed out that there were people working on silicon who would make a great contribution to him in time, but we were the wrong people.”

With work continuing on gallium arsenide, Cyril organised several industrial labs to put two or three people on various aspects of gallium arsenide research, and originated what he describes as “the idea of having exploitation in the hands of the common good”. To that end he formed the Gallium Arsenide Consortium.  He explained “Although these were competing companies, because the research was so difficult they were actually willing to have free discussions between them on the subject.”  Originally it was thought that the managers of the laboratories would not be very keen on people sharing their results, but eventually they became quite happy with it. It wasn’t called the Gallium Arsenide Consortium at first, it was called  Hilsum’s Consortium, so that if it went wrong, I would take the blame and nobody else.  It wasn’t until it actually began to clearly show results that it began being called the Gallium Arsenide Consortium.”

A further result of the research work was the formation of the European Solid State Device Research Conference, which united two separate national conferences into one international conference. It held its first conference in 1970, and it is still running, 50 years later.

Between 1955 and the early sixties, Cyril and his team developed many devices including semiconductor lasers and LEDS, all of which required patents. He explains: “I remember we made some quite nice devices including a tape reader which could be immersed in oil and still worked well. This was required by the Foreign Office.  The experience taught me quite a bit about patenting.  I also began to realise that the Admiralty was not terribly interested in exploitation of patents, though we had a whole series of patents and we were very conscious of the potential commercial applications for what we were doing.”

In 1964, Cyril moved to the Radar Research Establishment at Malvern when it became obvious that the then director of SERL was not interested in the team’s work on semiconductors. Cyril says: “I was lucky in that Malvern knew about me.  We had worked together on photocells for infrared missiles for some years.” When Alan Gibson, their leading light in semiconductors, moved to the University of Essex, as a senior professor, Cyril was invited to join RRE to work on his own specialities. Cyril explains: “Not replacing Alan in any way, but more or less changing what Malvern had been doing.” The shift saw a move away from silicon towards more exotic materials, Cyril adds: “They were quite happy to see if we could do something on gallium arsenide together.”

RRE, as a radar establishment, was very interested in the prospect of a microwave oscillator based on Cyril’s research into differential negative resistance and his discovery of a new property of gallium arsenide which he believed was going to prove extremely useful. The work came together through the Gallium Arsenide Consortium, using material made at Plessey. The work resulted in both Plessey and Mullards commercialising the first microwave oscillator based on the negative resistance effect in gallium arsenide in 1966.  STL followed one month later. Cyril concludes: “All of them were making the same device, all done through the consortium.  A real triumph of collaboration.”

With the push by Harold Wilson for the UK to develop ‘white hot technology’, the Radar Research Establishment was moved under the newly formed Department of Technology, with John Stonehouse as the new Minister of Technology. Following a meeting between John and RRE’s director, John asked the team to start work on a programme looking at flat-panel displays. A working party was set up under the Head of Physics, David Parkinson. Cyril took over leading it when David was promoted to a role at headquarters. Cyril says: “I was saddled with a working party on flat-panel displays, and I knew damn all about flat-panel displays.”

Despite his lack of knowledge, the working party made a recommendation that the UK should start research on liquid crystal displays. It was necessary then to place external contracts. A meeting was called which included all academic staff  and representatives from industry who claimed they knew something about liquid crystals. Cyril adds: “I realised after the meeting that there was only one person in the room who understood anything about liquid crystals, and that was George Gray from Hull.” George was offered a contract to carry out research on stable liquid crystals and found an answer two years later, with his invention of the biphenyl family. Peter Raynes, recruited by Cyril two years earlier, then showed how to compose a biphenyl mixture suitable for displays. Cyril says: “The world had been trying hard to find a stable material and suddenly we had it.” Cyril’s next step was exploitation and patenting. He persuaded a chemistry-based company called British Drug Houses, later BDH, to make the material in quantity, patented the invention and it, with other display inventions by the Malvern group, made over £100 million for the Government.

By the age of 57, Cyril had progressed to Chief Scientific Officer, and now was the most senior working scientist in the Ministry of Defence and for a few months, the whole of the Civil Service.

In 1983, he was invited to join GEC, the largest electrical and electronics company in the UK, as  Chief Scientist, working at the Hirst Research Centre in London. There he was responsible for numerous projects in the Centre, including a programme on high temperature superconductivity, and research on olfaction. He also had to establish a small laboratory to develop his own ideas. He says: “I had to set up a Chief Scientist Unit and I was pretty progressive because I insisted they should be gender neutral. I would take on 20 people and ten of them were going to be female. One of the women is now running quite a lot of research.”

Cyril was also responsible for the Long-range Research Laboratory which included research on nanotechnology. In 1985 he was promoted to be Director or Research, GEC. He was also a visiting professor at UCL and had been President at the Institute of Physics.

At the age of 68, Cyril gave up the role of Director of Research at GEC but continued working for some years with GEC. Later, as a consultant, he worked with  Unilever and Cambridge Display Technology.

Alongside all of these activities, Cyril became involved with a venture capital group through a friend. He says: “One of the things that venture capital groups always lacked was somebody who knew some technology. When they got proposals that included technology applications, they didn’t know what questions to ask, so I got into that and worked with them.” One of the companies in which the group invested was Peratech, working on Pressure Sensors, and they asked him to be a non-executive director and Head of Science, which he did for a number of years.

Having helped many people to patent inventions, he says: “I am still patenting things myself, at the advanced age of 94. I’m talking hard with companies about the exploitation of patents and trying to use the knowledge I have gained after many years. I lecture on intellectual properties at Imperial College on the MSc course, because this isn’t something which is generally covered by normal courses. What you do with your inventions is a very interesting problem for people. It shouldn’t be something that you leave entirely to someone else.”

Cyril has had a medal named after him by the British Liquid Crystal Society which is presented annually to young people in the early stages of their career and research.

On the subject of decisions he has made through his career, Cyril says: “I didn’t make any key decisions; they were always made for me.  The only decision I really made was when I was 57 when I decided, together with my wife Betty, that we should move to London to GEC which put me in a different context and enabled me to stay active for longer.”  Cyril goes on to say that while Malvern was lovely it was no longer the centre of activity. He adds: “Coming to London, it’s very easy to still take part in science.”

Of all of his achievements, Cyril points to the work he did on negative differential resistance as the thing that he personally did that had a pronounced effect. He says: “I can say that the things I did have also really been the roots of quite a lot of the devices that have been used in electronics for many years, including the fact that all computers use a flat screen.  I don’t know whether it would be our flat screen, but I’m pretty certain liquid crystals would not have got going if it hadn’t been for my initiative with George Gray and Peter Raynes.”

As well as setting up a scholarship at Malvern Girls’ College in memory of his late wife, Cyril also set up the Karen Burt Memorial Award with the Women’s Engineering Society in honour of his daughter, also a scientist who died at a young age.

Cyril is a Fellow of the Royal Academy of Engineering, the Royal Society, and an Honorary Member of the American National Academy of Engineering. In 1990, Cyril was awarded the CBE for services to the electrical and electronics industry. Among many other awards from international scientific and engineering institutions and societies he was awarded the IEE Faraday Medal in 1988, and the Glazebrook Medal of the Institute of Physics in 1998,. In 2007 the Royal Society awarded him their Royal Medal in recognition of his many outstanding contributions and for continuing to use his prodigious talents on behalf of industry, government and academia to this day.

Interviewed By: Elisabetta Mori on teh 17th January 2020 at BCS London

Transcribed By: Susan Hutton

Abstracted By: Lynda Feeley