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More and more the LED bulb arises as a rival of these fluocompact and halogen sisters. But what is the acronym LED or DEL? And who is really this little last of the luminaire market?

LED bulbs

LED bulbs

LED or LED? A bit of terminology and history

LED means «Light Emitting Diode» that is to say " Light emitting diode " in good French, which is abbreviated as LED. And no one being a prophet in his country, it is rather the Anglicism LED which prevails on the French DEL!

LED is the newest member of the family of bulbs. Yet the discovery of the phenomenon of electroluminescence by English Henry Joseph Round, dates from 1907. Twenty years later, Oleg Vladimirovich Losev filed the first patent of what will become an LED. In 1936, the French physicist Georges Destriau continued work on electroluminescence. But it was not until 1962, that Nick Holonyak Jr. and S. Bevacqua, researchers at General Electric, created the first light-emitting diode with visible spectrum. Red in color, their colleagues will call it "the magic device" because the light emitted was visible to the naked eye. These LEDs you know them, these are the red lights, yellow or green indicating that your electrical appliances or household appliances are powered.

During the 1990s, the Japanese company Nichia, develops the first blue LEDs then the white LEDs. The LED then leaves the restricted area of ​​the indicator light to directly compete with the halogen bulb and the compact fluorescent.

How does an LED bulb work?

To simply summarize a technology that is not, it should be known that a diode is an electronic compound comprising two semiconductor elements that allow the passage of the current in a given direction. A semiconductor being a crystalline body which is at one and the same time conductive, that is to say that it allows current to pass through and insulation. Electroluminescence, on the other hand, is the faculty possessed by certain bodies to become luminous when they are traversed by an electric current.

Skillfully mix all and you get an LED where the 2 layers of semiconductors have opposite electrical characters. This potential difference at the junction of the two layers, releases energy in the form of photons.

According to the nature of the semiconductors used, the photons thus created will emit in visible wavelengths for our eye: red, yellow, green, blue.

The use of LED bulbs in our daily lives

Since they have gone from experimental to consumer products, LEDs have found very different fields of application. Not only have you been around them since the 60s with the lights of all your appliances, radio alarm clocks, hifi devices but also in the headlights of your car, in your flashlight, the backlight of your computer screen or your TV, your Christmas garlands, and of course your light bulbs.

LED technology has many advantages:

  • Low power consumption.
  • A lifetime from 20,000 to 50,000 hours.
  • Good light output of 20 to 100 Lumens / Watt or more.
  • A near zero luminous inertia, that is to say that an LED bulb turns on and off in a very short time and immediately reaches its maximum efficiency. It is interesting for places of passage where the light is often on and off.
  • Small size and solidity foolproof.
  • of the different colors according to the wavelengths emitted by the semiconductors or through the combination of a blue diode and a phosphor.
  • She does not emit ultra-violet. An undeniable asset when it comes to illuminate objects likely to be damaged by light such as paintings for example.
  • Medium power LEDs emit little heat and therefore pose less fire risk than a halogen bulb.

On the other hand, the blue light released by certain LED bulbs presents a danger for the retina and the children.

For further:

  • What is the price of an LED bulb?
  • Give a festive air to your home thanks to the LED garland
  • The LED spotlight, economical and practical

Video Instruction: LED bulbs making process