incandescent bulb

telegraph.co.uk
Return of incandescent light bulbs as MIT makes them more efficient than LEDs
Ever since the EU restricted sales of traditional incandescent light bulbs, homeowners have complained about the shortcomings of their energy-efficient replacements.

Researchers at MIT have shown that by surrounding the filament with a special crystal structure in the glass they can bounce back the energy which is usually lost in heat, while still allowing the light through. They refer to the technique as “recycling light” because the energy which would usually escape into the air is redirected back to the filament where it can create new light.

“It recycles the energy that would otherwise be wasted,” said Professor Marin Soljacic.