Light creates clarity, overview and accents — full-spectrum LEDs open your eyes
The invention of the incandescent lamp and its further development by Thomas Alva Edison laid the foundation for the electrified lighting of streets, houses and eventually homes.
The World Exhibition in Paris in 1878 was one of the first major events where electric lighting was realised using carbon arc lamps.
In 1879, Edison improved the concept and created the mass-market light bulb — at that time still equipped with a high-resistance carbon filament. But already inside the glass bulb still typical today, which must be largely airless, a vacuum, so that the filament does not burn. Removing air, or oxygen, is essential for both the incandescent lamp and the modern halogen lamp.
In halogen and xenon lamps, instead of a vacuum, halogen or the noble gas xenon is used, among other things, to displace oxygen.
The fluorescent lamp — often incorrectly called a neon tube — was actually invented earlier, but only reached mass-market maturity in 1938, thanks to patents for coating the tube with phosphors while simultaneously increasing the gas pressure.
Fluorescent lamps are filled with gas: mercury vapour and argon are directly excited to glow by an electrical voltage and generate large amounts of invisible but highly energetic ultraviolet radiation.
This radiation then produces visible light when it hits the glass bulb coated with fluorescent substances.
There is no filament, and the operating temperature is significantly lower, meaning less heat development.
Fluorescent lamps are therefore much more energy-efficient, but they have one glaring disadvantage: the toxic substance mercury.
Disposing of a fluorescent lamp is not trivial, and even breaking the glass of such a lamp, for example at home, can lead to serious health risks.
The light of the 21st century...
It was a long time coming and still required fundamental inventions — the LED.
The light-emitting diode is a so-called semiconductor whose electrical properties correspond to those of a diode. A diode is a kind of one-way street for electric current.
When electric current flows through the diode in the forward direction, it emits light with a colour, or wavelength, determined by the semiconductor material and the so-called doping.
For around three decades after its invention in 1962, it initially served only as an indicator light and for signal transmission. The small red lights on many hi-fi systems or other electrical devices of that time indicated that the device was “on” and were usually monochrome red LEDs.
But it took until the end of the 1990s before isolated applications of LEDs as light sources for everyday use appeared.
Only recently, in 2014, three researchers were awarded the Nobel Prize in Physics for the invention of the “blue LED”.
It was precisely this invention that made highly efficient, very bright LEDs with a balanced colour spectrum possible.
The complete range: SORAA full-spectrum LED
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