LED lights, what are they and how do they work?

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Back in 2003, Audi presented at the Frankfurt Motor Show that would be the seed of the Audi R8, a concept called the Audi Le Mans quattro. In addition to the spectacular design, highlighted the LED headlights it equipped, a technological breakthrough that has gradually been extended and now is a highly valued option in high-end cars.

I take the glove that DB9 user threw me during the last part of our test of the Audi A6 hybrid, which asked for a review of the LED headlights that equipped our unit of tests. Let’s see what these headlights are and how they work, in addition to reviewing the models that currently offer these types of headlamps as an option or as a series.

LED lights, what are they and how do they work

What is an LED?

I’m not going to go into the depths of explaining what an LED is, but I think it’s always good to know how the basic component of these types of headlamps works. LED stands for Light-Emitting Diode, light-emitting diode in Spanish. Your own name, then, tells us in broad outline what an LED is.

The diodes are pieces of electronics made of semiconductor materials and the basic property of utility electronics is to conduct electricity when the current is applied in one direction, blocking the current when applied in the opposite direction. LEDs in addition to having this basic property, which a priori is not very useful at the time of giving light, have the property of emitting light when the current flows through them.

Applying the LEDs to a car headlight

LEDs have two characteristics that make them desirable when forming part of a headlight. On one side we have that the LEDs do not have just light inertia, that is to say, the time that elapses between that the LED starts to light and is emitting light to 100% of its capacity is very low, in fact practically priceless. This time is minor compared to the light inertia of halogen or xenon headlights.

On the other side we have that the LEDs have the characteristic of consuming very little energy in relation to the amount of light emitted. Being very simple electrical components, in which the light does not come from an incandescent filament or an electric arc, hardly any energy is lost in the form of heat, transforming much of the electricity that travels the diode in light and with a limited heating.

For lighting a car you need a fairly powerful light source. The problem with LEDs is that although they are very efficient, they usually emit little amount of light, so for automotive LED groups are used with the highest possible power but avoiding the larger ones that normally require additional systems. cooling by dissipators.

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Another problem with LEDs is that there is nothing more than experimental LEDs that emit white light that is desired in the automotive industry.you can read LED headlights review before you get install into your car LEDs are used with yellow phosphorescent elements that convert ultraviolet or blue LED light into white light, such as fluorescents or energy-saving bulbs in our homes. This makes the LED headlights have some noticeable shade in bluish colors, although the light is predominantly white.

The point of light that an LED generates is of a very small size, reason why they are encapsulated in a small cover of transparent plastic or of other colors, that serve to protect the electronic component of blows and strange materials. The problem with these capsules is that they make the light not directly direct, it is diffuse, which means that a special work is needed in the optics to orient the light to where it wants to command, that is, to the highway.

The LED headlights have an integrated electronic management system that is responsible for controlling the functions and power of the headlight. There are several types of LED headlights, although the most common are multi-face reflectors and projectors. The first type uses several reflectors of small size, each endowed with an LED that can be oriented towards the road (of LED seen) or towards the reflector (of hidden LED).

Properly orienting these reflectors and lighting groups of LEDs together is how you obtain various types of beam, such as short, long or anti-fog. There are even manufacturers that will apply this system to develop adaptive lighting systems by turning off or on the various headlight reflectors. These types of headlights are used for example in the Audi (as this hybrid A6) or in the Seat (as in the Seat Leon). These reflectors are sometimes covered by a dispersion glass to better distribute the light.

The other type of LED headlamps that exist are the ellipsoidal projector. These carry groups of LEDs on the inside, behind a lens that is responsible for directing the light emitted by the LEDs that are inside the headlight. These types of headlights with projector are used by manufacturers such as BMW, Mercedes or Lexus, although in some cases they use combined systems of reflector and projector.

A very white light, a practically nonexistent light inertia, a useful life that exceeds the own car and a very low energy consumption, these are the most notable and appreciable characteristics of LED headlights. Their counter is that at the moment the cost of these advanced headlights is still quite high.

Other LED lights in the car

We are going to add here an edicional note to the article to talk about the LED rear lights and other LED lights that equip the cars. In lights that are not the headlights of a car you do not need to focus the light in a specific direction. This facilitates the implementation of diodes, as they do not require complex reflective surfaces or lenses.

It is becoming increasingly popular to use LEDs on the indicators, daytime running lights, side indicators and in general on the various lights of the rear lights, many cars offer them as standard and many others as an option. They have the enormous advantage, which we have mentioned before, of a useful life that is theoretically superior to the life of the car, it is not necessary to change them never, although like all things, can be spoiled.

We leave you with a list of cars that can equip or equip as standard LED headlights that have starred in this article.

Car carrying or can carry LED headlights

  • Audi A6
  • Audi A7
  • Audi A8
  • Audi r8
  • BMW 6 Series
  • BMW 7 Series
  • BMW X5M
  • BMW X6
  • Cadillac Escalade
  • Lexus GS
  • Lexus LS
  • Lexus RX
  • Mercedes CLS
  • Mercedes E Class
  • Mercedes GLK
  • Nissan Leaf
  • Seat Leon
  • Toyota Prius
  • Toyota Prius +

If you have forgotten any of them, we would appreciate it if you let us know in the comments to complete the list.

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