https://en.wikipedia.org/wiki/Haitz%27s_law https://en.wikipedia.org/wiki/Haitz%27s_law Every decade, the cost per lumen (unit of useful light emitted) falls b

https://en.wikipedia.org/wiki/Haitz%27s_law https://en.wikipedia.org/wiki/Haitz%27s_law Every decade, the cost per lumen (unit of useful light emitted) falls by a factor of 10, and the amount of light generated per LED package increases by a factor of 20, for a given wavelength (color) of light.