Car xenon lights have been around for 25 years. We’re shedding some light on both myths and technology.

The request was understandable – please more light at the front of the car but please no higher energy consumption. Got it. Clever experts therefore thought in the late 80s that whatever can be bright on the sun could also be bright on a car. No problem, at least none that couldn’t be solved. Big halls and public squares had long been illuminated by gas discharge lamps. So the newly designed lamps for cars no longer housed conventional filaments but a small quantity of the inert gas xenon. If you apply a high voltage, the gas changes to plasma. A little bit like on the sun. If you want a bit more detail, a lot of electrons break away from the then positively charged remaining atoms, moving about independently from them. That’s what we perceive as bright light in this case.

The temperature of xenon lights in the early series was pretty close to that of normal daylight at approximately 5000 Kelvin. Despite the smaller construction of headlights and up to 50% higher luminous efficacy, they don’t require more energy, but the roads are illuminated much better and further. In 1991, the BMW 7 Series was the first production vehicle for which optional xenon headlights were offered. As early as 1997, more than 50% of flagship cars from BMW, Porsche, Mercedes-Benz and Audi were ordered with xenon lights. From 1999, the Mercedes C215 could be ordered with bi-xenon for the first time. So now high beam also worked with gas discharge lamps. Old vehicles couldn’t just be upgraded to xenon headlights through plug & play because the new lamps require their own high voltage source to ignite the gas. So the whole lamp system always needed to be changed, and the costs for that were (and still are) quite significant.



Sounds great. And it is. Nevertheless, in the beginning other drivers would complain quite often that the “new” lights were dazzling them, adding that they were quite blue and not at all pleasant. This could be proven wrong in theory; xenon light isn’t bluer than daylight and the new headlights absolutely complied with the regulations when it came to illuminating the road.
So there’s a bit of psychology behind it, which could now be explained. The emission surface in many xenon headlights is smaller than in normal halogen headlights, which makes them look brighter at the same light output. The bluish light grabs our attention more than yellowish light, so this change in color also explains why it seems brighter than usual. This effect disappears little by little though because more and more vehicles are equipped with xenon lamps. And last but not least, blue light is more strongly dispersed by the lens in our eye than yellow or white light, which means that scattered light creates a shroud on the iris, leading the eye to believe that there’s glare. It’s all about perception.

I haven’t heard anyone complain about the “awful blue lights” for a long time. You see, it’s not so bad. Those of you who have xenon lamps in their cars can still improve them of course. Have a look here. And for those who don’t, well, Osram has other solutions to enhance your performance. May your vision remain unshrouded.

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  • Hello Jans Tanz,

    Very pleased to read/understand Gas Xenon, Bi Xenon from 199.
    Born, live in Karachi, Pakistan a large city with average cars 15 year old. With about 70% cars on road average 15years. Roads, street lights, aren’t managed by Muncipality hence most roads are without lights, or dim lights, now switching to LED.
    I had a fascination before I read your article that if we in Karachi switch Gas Xenon or Bi Xenon the city will be illuminated. Issue was it was not available. I’m surveying with local Muncipality for Osram LED from conventional lamps which were Philips, and the proposition is well recieved. Besides my request to install few Osram LED lights in a public park, which is well recieved and will be installed in coming month for the first time with OSRAM LED Street Lamp.
    Please tell me if my current halogen lamps in Misubishi Lancer 1.3 of 1991 be fitted in the head with Gas Xenon lamp or LED lamp in the old socket, in the old fitting and luminaire would be a show case to the Street Light and the Car model. This could possible be covered by local TV channels which will be aired for the innovative idea of street light is to put an Osram Gas Xenon, or LED head light. Pleae do reply. With approx. cost handling charges, costs. Thanks

    Haroon Rashid
    Interconnect Partners
    90 kokan society
    alamgir road
    Cell +82.302.8290909
    Telephone +92.21-34938683

    • Dear Haroon Rashid,
      thanks for your comment. Changing Halogen for Xenon lights is very expensive and time-consuming when there are no headlight sets available for your vehicle model. Please contact a reliable garage/mechanic for further information. We apologize for not being able to help.
      Kind regards, your OSRAM Automotive Team.