STOCKHOLM (AP) -- Isamu Akasaki and Hiroshi Amano of Japan and U.S. scientist Shuji Nakamura won the Nobel Prize in physics on Tuesday for the invention of blue light-emitting diodes, a breakthrough that spurred the development of LED technology used to light up computer screens and modern smartphones.

The Royal Swedish Academy of Sciences says their invention is just 20 years old, “but it has already contributed to create white light in an entirely new manner to the benefit of us all.''

Scientists had struggled for decades to produce the blue diodes that are a crucial component in producing white light from LEDs when the three laureates made their breakthroughs in the early 1990s.

Their work transformed lighting technology, paving the way for LED lights that are more long-lasting and energy-efficient than older sources of light.

“They succeeded where everyone else had failed,'' the Nobel committee said. ``Incandescent light bulbs lit the 20th century; the 21st century will be lit by LED lamps.

Akasaki, 85, is a professor at Meijo University and distinguished professor at Nagoya University. Amano, 54, is also a professor at Nagoya University, while the 60-year-old Nakamura is a professor at the University of California, Santa Barbara.

Akasaki said in a nationally-televised news conference that he had often been told that his research wouldn't bear fruit within the 20th century.

“But I never felt that way,'' he said. “I was just doing what I wanted to do.''

The Nobel committee said LEDs contribute to saving the Earth's resources because about one-fourth of world electricity consumption is used for lighting purposes.

“As about one fourth of world electricity consumption is used for lighting purposes, the LEDs contribute to saving the Earth's resources,'' the committee said.

On Monday, U.S.-British scientist John O'Keefe split the Nobel Prize in medicine with Norwegian couple May-Britt Moser and Edvard Moser for breakthroughs in brain cell research that could pave the way for a better understanding of diseases like Alzheimer's.

The Nobel award in chemistry will be announced Wednesday, followed by the literature award on Thursday and the Nobel Peace Prize on Friday. The economics prize will be announced next Monday, completing the 2014 Nobel Prize announcements.

Worth 8 million kronor ($1.1 million) each, the Nobel Prizes are always handed out on Dec. 10, the anniversary of prize founder Alfred Nobel's death in 1896. Besides the prize money, each laureate receives a diploma and a gold medal.

Nobel, a wealthy Swedish industrialist who invented dynamite, provided few directions for how to select winners, except that the prize committees should reward those who “have conferred the greatest benefit to mankind.''

Last year's physics award went to Britain's Peter Higgs and Belgian colleague Francois Englert for helping to explain how matter formed after the Big Bang.