Advantages and disadvantages of LED headlights

Light emitting diodes (LEDs) have been used in radio electronics for a long time. There they are used, for example, in optical relays or optocouplers for contactless signal transmission over an optical channel. Home appliance remote controls also send signals using infrared LEDs. Light bulbs that are used for indication and illumination in home appliances and all sorts of gadgets are actually also usually LEDs. A light emitting diode is a semiconductor element in which, when current passes through a pn junction, electron-hole recombination occurs. This process is accompanied by the emission of photons of light.

Despite the ability to emit light, LEDs have not yet been used for lighting. Until recently. Everything changed with the advent of super-bright components, which were suitable for creating lighting devices. Since then, LED-based lighting technology began to enter our lives and displace not only incandescent bulbs, but also the so-called energy-saving ones.

Application of LED technology in cars

The technological breakthrough has not gone unnoticed by automakers. Powerful and at the same time miniature LEDs made it possible to defunction innovative car headlights. At first they began to be used for parking lights, brake lights, turns, then for low beams. More recently, LED high beam headlights have also appeared. 

If at first LED headlights were installed exclusively on expensive models, then recently, as the cost of technology has become cheaper, they have begun to appear on middle-class cars as well. In budget models, the use of LEDs is still limited to auxiliary light sources - for example, position or running lights.

But tuning lovers now have a new opportunity to distinguish their car from the rest with spectacular LED backlighting of the bottom, logo and numbers. The color can be chosen to your taste. With the help of LED strips, it is convenient to highlight the trunk or completely replace the lighting in the cabin.

LED headlight device

The main goal of car headlight developers is to provide the maximum range of illumination, while eliminating the dazzling effect for oncoming drivers. Quality, strength and durability are also important. LED technology greatly expands the possibilities for headlight designers.

Although one individual LED is less bright than and even more so, due to its small size, a set of dozens of such LEDs can be placed in a headlamp. Together they will provide sufficient illumination of the road surface. In this case, a malfunction of one or two components will not lead to complete failure of the headlight and will not critically affect the level of illumination.

Good quality LED element is able to function for 50 thousand hours. This is more than five years of continuous work. The probability of failure of two or more components in one headlight is extremely small. In practice, this means that you will most likely never need to change such a headlight at all.

The power supply to the LED headlight is not supplied directly from the on-board network, but through the stabilizer. In the simplest case, you can use a rectifier diode plus a resistor that limits the current flowing through the LED. But car manufacturers usually install more sophisticated converters that maximize the life of the LED components. 

Automatic control of LED headlights

Unlike incandescent lamps and gas-discharge lamps, which are characterized by some inertia, LEDs turn on and off almost instantly. And since the light of the headlight is made up of the luminous flux of individual components, this makes it possible to quickly adapt the illumination depending on the traffic situation - for example, switch from high beam to low beam or turn off individual LED elements so as not to dazzle drivers of oncoming cars.

Systems have already been created that allow you to control the headlights automatically, without human intervention. One of them uses curtains, which, with the help of an electric engine, cover part of the LEDs. The curtains are controlled by a computer, and the detection of oncoming traffic is carried out by a video camera. An interesting option, but very expensive.

More promising is a system in which each element has an additional photodetector that measures its illumination in the off state. This headlight works in a pulsed mode. High speed allows you to turn on and off the LEDs at a frequency that is imperceptible to the human eye. The optical system of the headlight is designed. It turns out that each photocell receives external light only from the direction where the corresponding LED shines. As soon as the photodetector fixes the light, the LED will immediately turn off. In this option, neither a computer, nor a video camera, nor electric combustion engines are needed. No complicated adjustment required. And of course the cost is much lower.

Advantages

1. LED elements are small. This opens up a wide range of application, placement and design possibilities.
2. Low power consumption and high efficiency. This reduces the load on the generator and saves fuel. High energy efficiency will be especially useful in electric vehicles, where it will save battery power.
3. LEDs practically do not heat up, so a large number of LED components can be placed in one headlight without the risk of overheating. 
4. Long service life - about five years of continuous operation. For comparison: xenon lamps work no more than three thousand hours, and halogen lamps rarely reach one thousand.
5. High performance. Faster response of LED brake lights compared to halogen ones improves driving safety.
6. The ability to create headlights with automatic lighting control depending on the situation on the road.
7. High quality. Sealed design makes the headlight waterproof. She is also not afraid of vibration and shaking.
8. LED headlights are also good from an environmental point of view. They do not contain toxic elements, and reducing fuel consumption, in turn, reduces the amount of exhaust gases.

Disadvantages

1. The main disadvantage of LED headlights is the high cost. Although it is gradually decreasing, prices are still painfully bite.
2. The low heat dissipation keeps the headlight glass cool. This prevents the melting of snow and ice, which negatively affects the efficiency of lighting.
3. The design of the headlight is non-separable, which means that in case of failure it will have to be changed completely.

Conclusion

Among the drivers, the passion for xenon lamps has not yet subsided, and LED technologies are already louder and louder. The advantages of LED headlights are obvious, and there is no doubt that over time they will become more affordable and will be able to seriously replace xenon and halogens.

And on the way are car headlights using laser technology. And the first samples have already been created. Laser headlights, like LED headlights, have a long service life, and surpass them in terms of illumination level. However, there is no point in talking about them seriously yet - in terms of cost, one such headlight is comparable to a new budget-class car.