Smartphones, tablets and e-readers should have an automatic "bedtime mode" that stops them from disrupting people's sleep, a leading doctor says.
Professor Paul Gringras argued that the regulation should filter out blue light which delays the body clock and keeps people awake until later in the evening.
The doctor, from Evelina Children's Hospital in London, said each new model was "bluer and brighter".
He said manufacturers should show greater "responsibility.".
As the night gets darker, the body begins to produce the sleep hormone melatonin – which helps people fall asleep.
Certain wavelengths of light, those at the blue-green end of the spectrum, can disrupt the system.
Professor Gringras was part of a study, published in Frontiers in Public Health, analysing the light emitted by the devices.
He concluded that there was a clear trend for new devices to be larger, brighter, have higher levels and emit more blue light.
The professor of pediatric sleep medicine told the BBC News website: “This is great for daytime use, but terrible for nighttime use. There is a growing body of evidence that if you are in front of one of these devices at night it could prevent you from getting an extra hour of sleep.” That is why “bedtime mode” is necessary.
He said that some apps are already designed to reduce blue-green light emissions, and that a "bedtime mode" could automatically filter out blue light, as software like f.lux already does.
He said there needs to be “greater responsibility from manufacturers” and the “key is to automate.”
Professor Gringras added: "It's not good enough to say we're doing less and accept that this is the world we live in, they are entertainment devices but we need some protection from what they do at night."
