xenon "blue" lights

[wolfie]

There was a period that model manufacturers insisted on fitting bluish LED lamps into their locomotives. They too have uh, seen the light (pun intended!), and new designs now come with slightly yellow, or even white, LEDs instead.

That's probably a matter of availability. Until fairly recently, the only 3mm and 5mm white LEDs (sizes model manufacturers would use) were "cool white". The LED makers were going for efficiency at the expense of colour accuracy - even now, "warm white" is slightly less efficient than "cool white".

Also, there's no such thing as a "white LED" - what's sold as that are blue LEDs with a phosphor coating (yellow under reflected light with the LED off - look at any LED flashlight and you'll see). If the coating's too thin (i.e. cutting corners to save money), you'll get an even bluer tint, since not all of the original blue will be absorbed (and re-emitted at a longer wavelength). If you look at the specs, you'll see white LEDs claiming a 10,000 hour lifetime, but red, amber, green, and blue claim 100,000 - that's because the phosphor layer "wears out", so the tint will go more to the blue end as the LED ages.

[protege]

I wondered what had happened to those. They seemed to be everywhere for about a year, but now I see them hardly ever.

The fad seems to have ended. Probably...because the people that bought high-end Audis, BMWs and other expensive rides...got tired of seeing "their" lights showing up on shitbox Honda Civics and Chevy Cadavaliers But seriously, things seem to have moved to the "white" end of the spectrum. That is, many lamps now fitted to those cars are more white, than the more-yellow lights fitted to many cars now.

Oh, and it's not just in the real world either. There was a period that model manufacturers insisted on fitting bluish LED lamps into their locomotives. They too have uh, seen the light (pun intended!), and new designs now come with slightly yellow, or even white, LEDs instead. At the time, it was felt that the bluish lamps made the models more realistic. But, from personal experience, they didn't. Real locomotive headlights have a slight yellowish tinge to them

[wolfie]

I wonder how (or if) LED traffic lights solve this?

This issue has been discussed, and "put on an electric heater grid" looks to me to be the simplest answer. Another contributor has brought up the reason for combining taillights and brake lights/turn signals in a single bulb.

[TheHuckster]

Right... and the other side, if the air was too hot (possibly, over time, just engine compartment air in the summer, or definitely if you tried using the exhaust) then you damage the plastic. Hot bulbs or electric heat would be the way to go.

I wonder how (or if) LED traffic lights solve this?

Traffic lights in the north typically have hoods over them to protect them from being covered in snow.

http://www.featurepics.com/FI/Thumb3...ght-322410.jpg

[HYHYBT]

Right... and the other side, if the air was too hot (possibly, over time, just engine compartment air in the summer, or definitely if you tried using the exhaust) then you damage the plastic. Hot bulbs or electric heat would be the way to go.

I wonder how (or if) LED traffic lights solve this?

[wolfie]

Headlight lenses are typically made of plastic (poor heat conductor), so would be hard to get heat from the edges to the center. Even if they went back to glass, it's still not all that great. "Engine compartment" isn't necessarily a great (in terms of collecting it) source of heat - there's a reason car heaters run off coolant, and the old air-cooled VWs used a separate fuel-fired heater rather than trying to collect heat from the engine compartment.

[Andara Bledin]

Who said anything about hoses? All you need is a simple solid heat exchanger that goes from the engine compartment to the headlamp glass.

It would have the added bonus of working far more quickly than the electric heating grid you find in rear windows and having almost nothing about it which could break down.

[wolfie]

This is a very simple engineering problem. Car engines build up massive amounts of heat, and it would be pretty damn trivial to use some of that with a radiator system that would, as a bonus effect, keep the lamp glass warm enough to not ice over.

Not quite so simple. Extra hoses mean more places to leak. Having the coolant flowing between the layers of a double window of the light leads to even more problems - coolant is dyed, so it would affect the colour of the light. Most new vehicles use long-life coolant, which is dyed red, and red lights visible from the front are prohibited on non-emergency vehicles.

Better solution would be electric heating grids (come on when the rear defroster is on - or for trucks with no rear window, when the mirror heat is on). Legislate that to be certified as street legal, a lit headlight assembly must NOT build up ice under specified conditions (air temperature, temperature of the vehicle to which the lamp assembly is mounted, wind speed, "standard" spray nozzle a set distance in front of the lamp assembly). Let the manufacturers figure out how to do it.

[kamn]

I've seen the LED's before. No, no problem with those, other than the annoying colour. I can still see after getting flashed by an LED flashlight without a still image in front of my eyes, just need the eyes to readjust to the level of darkness.
I can't say whether or not the cars that have the new blue lights are retrofitted or not, but most of the ones that blind me are from brand new, expensive looking ones (the times when I could clearly see the make and condition of the car). Then again, we're a bit behind the times, as far as trends go, and very status oriented (sadly), so it's probably assholes who want to look big on the road that are doig this. Sadly, because no amount of legislature is going to prevent them from doing it. Might as well not renew my driving license if this keeps up...

[Andara Bledin]

What do I consider the big problem with LEDs? They're too efficient. Many times, after driving through icing conditions, I'd make a "pit stop" and see that my low beams are clear but my high beams have a half inch of ice built up on them (which would seriously distort the beam pattern). Why is this? It's because I was running my low beams, which (being incandescent) generated enough waste heat to keep ice from building up.

This is a very simple engineering problem. Car engines build up massive amounts of heat, and it would be pretty damn trivial to use some of that with a radiator system that would, as a bonus effect, keep the lamp glass warm enough to not ice over.

In other words, it's not a good reason to avoid LED lights; you just have to not try to treat them like incandescents.

Also, blue-dipped bulbs look nothing like xenon lamps. They look like blue-dipped bulbs, which is just kind of sad, really.

[wolfie]

There are 2 kinds of "blue" headlights - gas discharge (VERY expensive, and required to have a leveling system to avoid excess glare) and blue-dipped bulbs for conventional headlights.

Due to differences in the light (arc is brighter at the ends, filament is brighter in the middle), HID retrofits have to replace the ENTIRE assembly. Some cheaper systems use the original reflector and lens - these don't have the proper beam pattern, and (in Canada and the U.S.) are not street legal.

The blue-dipped bulbs are purely cosmetic (get the colour of HID without the expense), and (in Canada and the U.S.) are not street legal.

You're gonna LOVE (sarcastic) the new LED headlights that are coming out - they also tend toward the blue end of the spectrum. They're even being offered as drop-in replacements for conventional sealed beams - and I wouldn't touch those with a 10 foot pole.

What do I consider the big problem with LEDs? They're too efficient. Many times, after driving through icing conditions, I'd make a "pit stop" and see that my low beams are clear but my high beams have a half inch of ice built up on them (which would seriously distort the beam pattern). Why is this? It's because I was running my low beams, which (being incandescent) generated enough waste heat to keep ice from building up.

[SkullKing]

some of those are indeed hazard and have been outlawed in some places.

My eyes are sensitive and it is easy for me to see how they could cause an accident

[patiokitty]

The bright blue headlights tend to leave quite the after-image on my retinas when I look at them. Which makes it really difficult when I'm driving at night so I have gotten to the point that if I see a set of them coming at me I tend to shift my focus towards the curb more. It saves on the blinding headaches and after-images. I'm mostly fine with regular headlights, as long as they are adjusted properly.

[Andara Bledin]

You get blinded because most assholes don't know how the fuck to adjust their headlights when they swap them out for custom components. >_<

Then again, neither does the dealership that did a recall swap on my headlights a couple of weeks ago. In my case, though, the right one is pointed far too low, so I'm not destroying anyone's night vision.

I actually much prefer blue tinted lights when driving; it provides a cleaner and clearer image of what's actually on the road. Yellow and orange tinted lights can all go die in a fire; they give comparatively crap visibility and give me a headache to boot. Sodium street lamps are the devil. >_<

[Gravekeeper]

I don't know whether it's my own sensetivity (none of my friends seem to be as bothered about them), if it's genetic (my brother is, my father is), or what's going on, but these bloody lights cause me to go completely blind for 2-5 seconds after they pass me (depending on the intensity).

Fun fact! Sunlight has a blue component that your body reacts too. It tells your body hey! The sun's out! Whereas conversely in the evening, the light hue at sunset shifts to red. Telling you its night time. Relax.

So when you get hit by blue light, your eyes go "WTF! SHIT CHRIST THE SUN?!". This is why when you first turn on your computer in the evening the monitor seems to stab you in the eyes for a few seconds until your eyes adjust ( and why working on a computer at night makes it harder to get to sleep later ). Or why "cold" lights at night like white LEDS or blue neon seem harsh on the eyes. Because you're confusing the shit out of them. While comparatively, "warm" lights like incandescent don't bother you at night. Because they lean red.

Or why when you get hit by blue Xenon headlights it blinds you. -.-