Tech visionaries have promised us a bright new world where cool and efficient white LEDs, based on blue ones, will replace the wasteful little heaters known as incandescent light bulbs. More than a dozen countries have already enacted legislation that bans, or will soon ban, incandescent bulbs. But it’s hard to imagine LEDs dislodging incandescents and coming to dominate the world electric lighting industry, unless we can defeat droop. Read more ….