Most commercially available white light emitting diodes (LEDs) emit lots of light in the blue wavelengths (430 – 500 nm). The retinal ganglion cells in the eye are highly sensitive to blue wavelengths. Do you know what this means for your biology, your health?

Nobel Lecture: Background story of the invention of efficient blue InGaN light emitting diodes*

*The 2014 Nobel Prize for Physics was shared by Isamu Akasaki, Hiroshi Amano, and Shuji Nakamura. These papers are the text of the address given in conjunction with the award.

Using blue LEDs, highly efficient white light sources become possible. This can be achieved by converting part of the blue light emitted from the LED to yellow using a phosphor (Nakamura, Pearton, and Fasol, 2000). To the human eye, the combination of blue and yellow light is perceived as white. A white LED can be created by embedding phosphors in a plastic cap which surrounds a blue LED (see Fig. 3). Higher quality white light can also be created by mixing blue light with other colors as well, including red and green (Pimputkar et al., 2009).

Source: https://journals.aps.org/rmp/abstract/10.1103/RevModPhys.87.1139

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