Turn on a laptop, a phone, or a hospital monitor and there is a reasonable chance its screen owes something to work Cyril Hilsum began in a government laboratory in the English countryside more than half a century ago. Hilsum, the British physicist who led the research that made liquid crystal displays practical and helped build the UK's first semiconductor laser, died on September 23, 2026, at the age of 101.

The screen work was not his first act. Born in the East End of London on May 17, 1925, to a street trader father, Hilsum later recalled learning to read by age three and taking apart every toy he was given to see how it worked. He attended Raine's Grammar School in Stepney, evacuated during the war first to Brighton and then to Camberley, before earning a physics degree, with mathematics as a subsidiary subject, from University College London in 1945.

His early government career produced one of his favorite stories. Posted to the Admiralty Research Laboratory in Teddington in 1947, Hilsum worked alongside researchers at the neighboring National Physical Laboratory, among them Alan Turing. "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," Hilsum recalled in a 2020 interview for the Archives of IT oral history project. "It's one of my claims to fame: I beat Alan Turing at chess."

At 25 he was promoted to run the infrared research group at the Services Electronics Research Laboratory in Baldock, developing indium antimonide photocells before taking charge of its gallium arsenide work and founding an industrial consortium to develop the material further. In 1964 he moved to the Royal Radar Establishment at Malvern, where his group built the UK's first semiconductor laser and the first microwave oscillator exploiting the negative resistance effect in gallium arsenide, work with direct military application in a miniature radar system, called Claribel, that could trace a bullet's path back to a sniper.

It was also at Malvern that Hilsum directed the flat panel display programme whose work would prove the most consequential of his career. His team there, working with the University of Hull and the chemical maker BDH, invented the first stable liquid crystal compounds, called cyanobiphenyls, according to the Royal Society, which elected him a Fellow in 1979. The compounds became the basis of practical liquid crystal displays and eventually earned the British government more than 100 million pounds in patent royalties as the technology spread into televisions and computer monitors worldwide. "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," Hilsum said of his Hull-based chemist collaborator and his RSRE colleague in the Archives of IT interview.

In 1983 Hilsum left government service for industry, becoming chief scientist of GEC's Hirst Research Centre in Wembley and its research director two years later. He retired in 1995 at 70, though retirement proved relative: he went on to serve part time as chief science officer of Infi-tex Ltd, developing force sensors for textiles, and later consulted for Unilever and Cambridge Display Technology and sat as a non-executive director of the sensor company Peratech. At 97 he was still inventing, patenting a conductive sensor ink and eventually amassing more than 70 patents over his career.

His standing in British physics was formalized in parallel with the industry work. He was elected a Fellow of the Royal Academy of Engineering in 1978, served as President of the Institute of Physics from 1988 to 1990, and was appointed CBE in 1990 for services to the electrical and electronics industry. The Institute awarded him its Max Born Prize in 1987, its Faraday Medal in 1988, and its Richard Glazebrook Medal and Prize in 1998, and in 2007 the Royal Society gave him its Royal Medal, citing him "for his many outstanding contributions and for continuing to use his prodigious talents on behalf of industry, government and academe to this day." In 2006 the British Liquid Crystal Society created the Hilsum Medal in his honor, awarded to mid-career researchers advancing the field he helped found.

Hilsum's family carried his scientific bent forward and also shaped how he gave back. He and his wife, Betty, had two daughters: Karen Burt, a space scientist and systems engineer who worked on satellite programs at British Aerospace and later at University College London, and Lindsey Hilsum, who became international editor of Channel 4 News. After Karen Burt died in 1997 at 42, Hilsum and the Women's Engineering Society established the Karen Burt Memorial Award in 1998, presented annually to a newly chartered woman engineer, according to Physics World.

Hilsum kept working and kept marking milestones into his final years. On May 17, 2025, colleagues and family gathered at the Royal Society of Chemistry to celebrate his 100th birthday. "My birthday event was an amazing opportunity for me to greet old colleagues and friends," he said, reflecting on the technology he had helped build: "As scientists, we may welcome progress in the subject, but all can get pleasure in seeing the results in their home, on their iPhone, or especially in their hospital," he told Physics World at the event.

Hilsum's name now marks a scientific medal awarded in his field, and the memorial award his family sponsors continues to send newly chartered women engineers into their careers. The patents from his Malvern work still sit behind the screens most people read from every day, largely unremarked, which is close to how he described his own role: an engineer who insisted a laboratory curiosity be pushed into something that worked in the world.