4 Types of Headlamps You Must Know

Table of Contents

There is a saying that eyes are the window to the soul. As eyes of automobiles, headlights play a very important role when driving, especially at dark night.

With the development of science and technology, headlamp goes through upgrade and update. So does people’s needs and demands. Nowadays, lots of people are interested in or keen on headlights retrofit.

But before customing our headlights, it is of great importance to know and understand them, helping us save money, time and energy.

That is why we write this article.

Before starting the body, it is necessary to introduce headlamp’s inner structure breifly, mainly reflector type and projection type. You will see with half an eye by the following picture of the two types headlamps.

reflector headlights vs. projector headlights
reflector headlights vs. projector headlights

Usually there are mainly 4 types of headlights if classified by light source: Halogen, Xenon or HID (high- intensity discharge), LEDs (light-emitting diodes) and laser. Halogen and xenon bulbs, LED lamps with led chips on them, integrated laser lights can be often seen in headlamps.

Halogen, HID xenon, LED bulbs, laser headlamp
Halogen, HID xenon, LED bulbs, laser headlamp

1. Halogen

Literally, halogen headlamp uses mainly halogen bulbs as optical source.Improved on the basis of tungsten filament where working in a vacuum or inert-gas environment, tungsten-halogen lamps have better luminous efficacy and longer lifetime because of higher operating temperature and reversible halogen tungsten chemical reaction.

Until today, halogen headlamps can be seen everywhere since the first single-filament H1 bulb was introduced in 1962 while the dual-filament halogen H4 bulb, producing both high beam and low beam, released in 1971.

Much lower cost and enough light output above the minimum legal requirements are two of the most important factors that making the lamp popular in low-end cars.Besides, like a incandescent bulb of which light source excited by thermal energy, a halogen lamp has a continuous light spectrum keeping to the black-body radiation, so its light is similar to sunlight and eye-friendly. Also drivers can drive more safe in rainy foggy or dust days with halogen’s strong penetration in rain, fog or dust due to low color temperature which is about 3150K. When the bulbs are broken after long-time use or some accident happens, it is easy to find the replaceable ones in the market.

halogen projector for low beam, emitting yellowish lights
halogen projector for low beam, emitting yellowish lights

But as time goes, halogen lamps becomes increasingly difficult to satisfy people’s travel demand, especially at dark night, for the poor brightness as well as high energy consumption. People are always seeking better optic system.

2. HID (high-intensity discharge)

More than 25 years has passed since Hella company developed the first dipped beam HID headlamps. Now xenon lamps are frequently seen at middle and high-end vehicle models.

Unlike a halogen bulb having glowing filament inside, HID burner gives out light by an electric arc. Inside its UV-cut quartz glass tube, there are mixed chemical gas instead of filament, including xenon and monoiodide. As xenon bulbs cannot work on car’s low direct voltage, a ballast with external or internal ignitor is needed, by which 12V DC voltage can be instantly amplified to 23000V, then an electric arc is produced. When all metal salts are vaporized, the arc becomes stable, so does the light output.So there is a start-up delay, about 2-5 seconds, until full lighting HID, but many solutions are found to remove petential hazards. Different bulbs have different stable operating voltage, for example, D1 and D2 is AC 85V, D3 and D4 is AC 42V. Different from a filament lamp, which the SPD is a continous curve, like that of the sun, xenon burner’s SPD is discontinuous and the color temperature ranges from 3000K to 12000K. 5500K to 6500K is similar to sunlights, which is kind to human eyes and used most.

ROYALIN Bi xenon lens with HID bulbs and ballasts
ROYALIN Bi xenon lens with HID bulbs and ballasts

As a newer technology than halogen lamp, HID burners have presented many advantages. First, they produce about 2 to 3 more available lights than halogen bulbs to bright drivers’ sight in the dark. Research shows that people have faster reaction to roadblock with good xenon bulbs than halogen, thus improving driving safety. When broken down, their gradually dimming lights help dirvers win spare time at dark. Though increased brightness, HID bulbs shine with lower power consumption. If normal haogen lamps work at 55W, xenon burner only need 35W, about half energy saving. The reduced energy consumption means less fuel burning and then less CO2 emission. The last but not least, the average HID  operating life is about 2000 hours while 450 to 1000 hours of halogen bulbs.

Every coin has two sides. The most common complaint of xenon lamps is their high level of glare to oncoming road users due to improper usage. Different areas have different requirements for xenon headlights. For countries who apply ECE Regulation 48, HID headlamps must be equipped with automatic beam leveling control and the lens cleaning system. But the situation differs in North America where xenon headlamps are less popular. HID projectors for headlights are not street legal in USA. Also, HID is not as penetrating as halogen bulbs during rainy or foggy time if with higher color temperature. Besides, it is more expensive to produce, purchase, install and repair of xenon headlights than halogen, though energy saving and longer lifespan can offset some cost.

3. LEDs (light-emitting diodes)

With the new 21st century coming, LED headlamps are gradually developing and getting strong. In 2006, the  Lexus LS 600h / LS 600h L were firstly on volumn production to have LED low beams inside their headlamps which were factory-installed and supplied by Koito while high beam and turn signal lights used filament bulbs. In 2007, AL-Automotive Lighting put the first headlamps with all LEDs functions on Audi. In 2013, Audi introduced the first full-LED glare-free “Matrix LED” adaptive headlamps which were digitally controlled with 25 individual LED segments.

Just as the name implies, LED headlights use LEDs inside, usually in the form of LED chips with projector or vehicle led lamps. LED bulbs produce lights when current flows through it by using light-emitting diodes, a frequently-used semiconductor luminescent device. A suitable driver circut is required to operate LED bulbs, such as dimming and remote control. Thermal management plays a vital role in LEDS comparing HID and halogen bulbs, as high temperature will cause reduced brightness and failure. So heat sinks and colling fins or cooling fans are standard configurations to LED lamps. Vehicle LEDs are normally placed on aluminum circut boards for better heat dissipation.

ROYALIN RY-LP3024 LED bi-lens, low beam and high beam together in one
ROYALIN RY-LP3024 LED bi-lens, low beam and high beam together in one

People are continuously seeking energy-efficient and environmental-friendly electric lights due to energy resources decreasing and environmental problems such as global warming. LEDs lighting, which is cold light, is one of their research achievements. The energy consumption of LED lamp is only about 1/20 of a given halogen bulb. With much longer estimated service time than HID and halogen lamps, LEDs could work through the entire car operating life if with good cooling system and suitable voltage and current.It is easier to store and transport LED lamps because of their good stability and resistance to shake. The solid-state lighting is coated with epoxy resin. As compact and small in size, LED resources are flexible in designing their lighting fixtures. Different from xenon bulbs that need relatively large lenses to control their lights, LEDs work well in smaller reflectors or lenses. In addition, a wide range of colors can be emiited by the tiny green lights, single color such as white, blue, red, yellow or multiple colors together called RGB. There are lots of applications and shapes of such decorative products in automotive aftermarket, RGB angel eyes, RGB demon eyes, RGB led strips, etc, bringing various choices to consumers.

Though thought to be ideal illumination source, it is with certain difficulty to overall popularize LEDs due to technical restriction and higher cost. Also LED products vary in quality and the industrial standard lacks. Not all led headlights perform well in thermal dissipation, which will, to a great extend, affect their lifespan.

4. Laser

The word “laser” is an acronym of “light amplification by stimulated emission of radiation”. Though invented as early as LED lights, laser was first used in headlamps by Audi until after 2010. BMW i8 is the first production car to be sold with laser technology. Now only some luxury cars are equipped with certain laser function,  except for some retrofitted vehicles with laser projector lens.

Laser lighting has almost all the advantages of LEDs, and performs better. The illumination distance of laser is twice as long as LED lights. With smaller size than LEDs, laser lights give much more flexibility in appearance design. Under a given condition, the ernergy consumption of laser can be as half as LEDs.

As the newest lighting technology in headlamps, it is now hard to widespread laser lights dute to much higher cost and certain technical limitation. But with the development of science and technology, we believe that one day laser will be prevalent in most car headlights.

ROYALIN RY-LP4005 Bi-LED lens with Nichia laser inside to enhace the brightness of high beam
ROYALIN RY-LP4005 Bi-LED lens with Nichia laser inside to enhace the brightness of high beam

What is rational is actual and what is actual is rational. Different headlamps with different light sources have merits and demerits, auto makers usually combine several optical source together to reach a satisfying light effect, such as halogen with xenon, xenon with LEDs, LEDs with laser. Among so many headlamps, choosing what works best for us is very important when plan to buy a new car especially retrofit your old headlights. By getting insight into automotive lighting, you will handle with ease when intend to custom your headlamps.

Obviously you are a true fan and eager to know more of auto lights as you read far here. There are lots of useful  knowledge in our ROYALIN website with continuous renewal, enjoy yourself here! Please also feel free to contact us if any questions, we will spare no effort to help you.

Thank you very much for your valuable time here.


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Levi Chou

Levi Chou

Hi, I’m Levi Zhou, the founder of royalincarparts.com, I’ve been engaged in auto parts aftermarket for decades, and the purpose of this article is to share with you the knowledge relating to car lighting retrofit from a Chinese supplier’s perspective.

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