1879, Vital flame standard as

 1879, Vital flame standard as to avoid inconvenience, recommended solidification of pure   LED Bulb  platinum surface trough one square centimeter emitted light intensity as a luminous intensity standard. For various reasons (for example, the purity of platinum is not higher), making its poor reproducibility, failed to adopt. But this idea of ​​the later development of luminosity have a certain impact. LED Module

In 1879, Thomas Edison invented the incandescent lamp, artificial lighting become a reality, but also to promote the development of photometric quantity. 1909 Britain, France and the United States related research institutions, in order to unify and improve the luminous intensity of the international scope of the protocol defined using the carbon filament incandescent light intensity, ie  LED Flexi Strip

Derived from the pentane lamp 45 with a group consisting of carbon filament incandescent average luminous intensity. And called it "the International Candlelight."