The hundreds of experimental failures that paved the road to winning the Nobel Prize for physics was fun, rather than frustration, one of this year's three Japanese-born laureates said Friday.

Hiroshi Amano, 54, sat next to Isamu Akasaki, 85, his one-time mentor-professor, when they met the press at Nagoya University in central Japan days after they were honoured alongside Shuji Nakamura for inventing the blue LED.

"I've never thought I wanted to quit in my research," Amano said. "I would always fail in experiments, which I did at least three times a day.

"I would go back to my apartment disappointed at night, but I would always get some new ideas in the morning. I would say it was fun rather than pain."

When he first succeeded "after failing more than a thousand times, I was speechless," he said.

The Nobel committee honoured the trio this week for their pioneering work on energy-efficient blue LED lights, which it said were a potent weapon against global warming and poverty.

Red and green diodes had been around for a long time, but devising a blue LED was the Holy Grail that would allow the cheap and efficient production of white light -- and achieving it took three long decades.

The breakthrough came in the 1990s when the three researchers coaxed bright blue beams from semiconductors.

LED lamps emit a bright light, last for tens of thousands of hours and use just a fraction of energy compared with the incandescent light bulb invented by Thomas Edison in the 19th century.

The most advanced LED lamps now consume around five percent of the electricity of regular light bulbs and their performance is improving constantly.

Akasaki said he remembered the day Amano "dashed into" his laboratory.

"He was the first student who showed interest in my study of a blue LED," Akasaki said.

"I thought he was my type, a student who never gives up."

LEDs are now also commonplace in computers, TVs, watches and mobile phone screens.

Nakamura, who is now a naturalised US citizen won fame in Japan after suing his employer for a greater share of the spoils of the LED prize.

A court ruled he should be given 844 million yen (more than $8 million). His initial company bonus was only 20,000 yen.