Durham-based Cree has recently started selling a line of low-cost LED light bulbs that look like, well, light bulbs. Due to the stringent cooling required to keep advanced white-light LEDs shining brightly, most
A lighting device comprising first and second groups of solid state light emitters, which emit light having peak wavelength in ranges of from 430 nm to 480 nm, and first and second groups of lumiphors which emit light having dominant wavelength in the range of from 555 nm to 585 nm. In ...