Alan Bell obituary

My friend and brother-in-law, Alan Bell, who has died aged 67 after a motorcycle accident on holiday in Laos, was a world expert on DVD security and copyright protection who was granted more than 20 US patents.

Alan was a key member of the team at the RCA technology firm in the US that developed the first optical disk and invented the recording medium that coated the disk's surface, a breakthrough central to the subsequent developments of the CD and the DVD.