Adaptive Headlights

Page 2 of 5  


No it's not. By definition.

So the sun is blue? That's what provides daylight - not the sky.
--
*Drugs may lead to nowhere, but at least it's the scenic route *

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Daylight is only not-blue at the equator.

The sky is blue becuse of scattering of light rays which reflect the blue end of the spectrum.
--
Need Mercedes parts? http://parts.mbz.org
Richard Sexton | Mercedes stuff: http://mbz.org
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

The colour temperature of daylight varies by the time of day and weather conditions as well as latitude.
--
*Shin: a device for finding furniture in the dark *

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Yeah, but all things being equal, on a clear day at noon light is bluer towards the poles. 5000K is given at the equator by several sources (GE, Horst & Kipper) and 6500-7500K is given in "norther climes" whcih ranges from Boston to Denmark.
--
Need Mercedes parts? http://parts.mbz.org
Richard Sexton | Mercedes stuff: http://mbz.org
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
http://www.intellexual.net/hid.html
This site appears to provide some credible info on HID lamps along with some interesting 'prism tricks' employed by BMW and Audi that make their headlights appear blue from the side even though they are actually white (4100K). It seems clear from this site that the true high temperature 'blue light' systems only have 'bling bling' value as they provide less light and that the human eye is less able to see that light.
To the original poster with the night vision problem I would suggest that he work on the other end of the problem and get some night vison glasses. I have an emergent night vision problem and find these lenses help significantly, especially in the rain. They also have the added benefit of acting as BLUE BLOCKERS knocking down the intensity of the oncoming beams from the affluent but ignorant purchasers of the blue light systems who for some reason usually drive around with their high beams up.
wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Very few cars have HID main (high) beams. Mostly they add incandescent high beam while leaving on the HID dipped one - no different from many incandescent only types. But plenty of boy racer types replace standard incandescent bulbs with blue incandescent types for the reasons boy racers have - they're actually less efficient than standard ones. True HID lights as have been said needn't appear blue - except when warming up, and on the edges of a projector system which is caused by the lens and happens with incandescent types too.
--
*Why do overlook and oversee mean opposite things? *

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

They're actually very illegal. And really stupid; they emit less light than non-blue bulbs.
--
Need Mercedes parts? http://parts.mbz.org
Richard Sexton | Mercedes stuff: http://mbz.org
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I don't know the law in your country.

But said just that in the bit you snipped. ;-)
--
*I'm not a complete idiot, some parts are missing *

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I'm not aware of any country where they're legal. To some extent automotive lighting and signalling regulations are normalized on an international basis and you can almost certainly find a phrase similar to "all forward facing lights will be only of a white of amber color" in your countries lighting regulations.
Never mind the local cops will pull you over for yellow lights thus forcing yo uto spend a day in court having the judge read the regulation to the officer.
Nor does it help to show the officer at the time the relevant portion of the highway traffic act kept in the glovebox.
I took off the yellow capsules because of this which was a real shame, they worked SO well in nasty weather (most of the time here).
--
Need Mercedes parts? http://parts.mbz.org
Richard Sexton | Mercedes stuff: http://mbz.org
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I have much better than average night vision, which is why oncoming HID's hurt so much.
The LAST thing you want to do at night is wear any type of sunglasses that cut down on the amount of light that enters your eyes, blue or not.
--
Need Mercedes parts? http://parts.mbz.org
Richard Sexton | Mercedes stuff: http://mbz.org
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

As will high powered filament lights of a similar output. HIDs are far more common than aftermarket filament bulbs of the same light output - most light fittings and wiring can't handle 150 watt bulbs.
--
*Not all men are annoying. Some are dead.

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Yes and no. Of course any high powered bulb is going to melt a cheap base/socket. But again, the color of the light is an issue here. 160W bulbs by themeslves will get you some flashes from oncoming drivers even on lowbeam (and of course I'm talking H2's here). but, with a yellow capsule over the bulb, you (or at least I) didn't get that once.
--
Need Mercedes parts? http://parts.mbz.org
Richard Sexton | Mercedes stuff: http://mbz.org
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Richard Sexton wrote:

That is not necessarily the case. Remember how much you liked your yellow headlamps in bad weather, before you took them out of the car? Well, it doesn't matter where such filtration is applied (at the bulb, at the lens, at the windshield, at the driver's eyes), the effect is the same.
For any given intensity, the higher the blue content of the SPD, the greater the discomfort glare -- *WITHOUT* any significant corresponding increase in seeing performance. In the case of automotive headlamps, HID vs. halogen, the discomfort glare ratio with intensity held fixed has been found to approximate 1.46 (i.e., for any given intensity level, the HID headlamp produces 46% more discomfort glare than the halogen headlamp). There has been some discussion of using this effect in inverse fashion to optimize the effectiveness of emergent LED headlamps (i.e., tweak their SPD to contain less blue, permitting higher actual intensities without increased discomfort glare), but it has been drowned out by marketeers who demand that each new generation of headlamps be bluer and bluer and ever bluer because that's what they're geared up to sell.
Just as the population at large is split roughly down the middle into glare-sensitive and glare-nonsensitive individuals, so too is it split roughly down the middle into blue-sensitive and blue-nonsensitive individuals (not the same 50/50 split; i.e., there are individuals who are glare-sensitive, blue-sensitive, both and neither). The obvious upshot is that any given HID headlamp will strike some people as more glaring (and some people as MUCH more glaring) than it will strike others.
Me, I happen to be somewhat blue-sensitive, so cutting the blue out of the light reaching my eyes at night is beneficial. Most commercial glasses sold for the purpose are grossly improper for the task; they have amber or orange or honey-brown lenses that block much too much useful light. You want to cut ONLY the blue. There are all kinds of fancy ads and competing claims for Blu-Blockers, Serengettis, etc. Most of it is BS. Your eye does not know whose name is on your lenses. Your eye also does not know how any given spectral gamut is achieved. The chief trait of an effective set of night-driving glasses is that they strongly attenuate the blue wavelengths so they don't reach your eye. When you look at a white light through this type of lens, the light will appear yellow (not orange, not amber, not brown). Interestingly, the human visual system -- with all its foibles -- does an excellent job of color correction; even when wearing glasses such as these it is not difficult to discern yellow from white road lines, for instance.
While cutting the blue and violet out of the spectrum has been shown to give some contrast-enhancement and glare-reduction effects during nighttime tasks under mesopic conditions (e.g., driving at night), it's very easy to overdo it, at which point the safety benefits of the reduced glare and enhanced contrast are overbalanced by the safety hazard caused by the absolute reduction in light reaching your eyes. IOW, it doesn't matter if a pedestrian's red shirt looks redder if you don't see him in the first place!
To help avoid an overly large absolute reduction in light, the lenses should be more towards selective yellow, and should NOT appear notably brown, orange and/or amber (which would indicate excessive attenuation of greens and yellows, which are of prime importance for human vision while driving at night). If you notice me repeating myself on this point, it's because it's so important.
Me, I had my night-driving spectacles made to my own specifications. An outfit known as "Calichrome" makes the correct-hue yellow dye. I picked a large, sturdy, inexpensive plastic frameset by Rodenstock(!), so as to handle as much of my peripheral vision as possible. Since I'm nearsighted, and nearsightedness tends to increase with fatigue *and* with dark (both of which conditions tend to exist at night), I had the lenses ground 1/4 diopter stronger than my normal glasses and my sunglasses. The lenses were then put through the Calichrome dye process to the correct-depth selective-yellow tint. I love them; they're perfect.
Your franchised "one hour glasses" type place probably won't know what the hell you're talking about and won't grind lenses to any but the prescription you hand them (those glasses-in-a-hurry places can't be relied on to adhere strictly to a prescription anyway...) so you'll have to patronize a good, competent independent optician. I had my current set made in Michigan when I lived there.
An excellent guide for the hue and tint is a "K2" type camera lens filter, available at any photo supply store.
DS
PS, remember too, the HID light source produces roughly 3x the light flux of the filament light source. This can be used by engineers for good (keep the optics the same size, increase total beam flux) or by stylists for evil (reduce the optics' size, keep beam flux "legally high"). When optical size is reduced, surface luminance increases, which creates a more glaring visual impression ("signal image"). And that's assuming quality optics; poor optics are another whole source of glare.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Silly rabbit, of course not. With sunglasses on you're getting less light from all sources into your eyes. Moonlight, streetlights, etc.
With filtered headlight you're getting less light from the headlights only.
It's not *really* the same is it?
--
Need Mercedes parts? http://parts.mbz.org
Richard Sexton | Mercedes stuff: http://mbz.org
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Dave Plowman (News) wrote:

Nope. There is nothing at all "closer to natural daylight" about the light from automotive HIDs; this is more marketeering crapola -- it is one of the many ways CCT ("Kelvin ratings") is hackneyed and misused in order to mislead the consumer. The CRI of the best automotive HIDs is between 72 and 74. The CRI of a properly-fed tungsten-halogen lamp is over 99. 100 is perfect. On a _practical_ level, this does not materially affect seeing performance under automotive HID light relative to TH light, but we do need to dispense with this "closer to daylight" noise.

Present automotive HIDs are contraindicated for fog lamp service, by dint of their SPD. There is a selective-yellow HID product from Philips, sold only in the Asian markets, that could be used to make extremely effective fog lamps.
DS
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Or uh, high beams?
Is there some way to bolt on these selective yellow HID fogs to older cars? I suppose they're a gazillion dollars?
--
Need Mercedes parts? http://parts.mbz.org
Richard Sexton | Mercedes stuff: http://mbz.org
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Richard Sexton wrote:

No, they wouldn't be particularly advantageous for high beams.

There are no selective yellow HID fogs. Perhaps I didn't make myself clear; the product I described is selective-yellow D2S and D2R automotive HID bulbs.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

This is too confusing. Your phone is about to ring.
--
Need Mercedes parts? http://parts.mbz.org
Richard Sexton | Mercedes stuff: http://mbz.org
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Dave Plowman (News) wrote:

Are you sure about that Dave? I thought I had read somewhere that the eye is *less* responsive to blue light than longer wavelengths, especially yellow. OTOH, I also know the eye is also not very sensitive to red light considering that is the color used in "night rigging" ships to maintain better night vision of the crew. Perhaps the eye's sensitivity drops off at both ends of the spectrum?
> But of course HID lamps *are* brighter so more likely to offend

Yes, so even if the eye is marginally less sensitive, the increase in light volume provides both the driver and the oncoming traffic more signal to the brain.
--
-Fred W

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

There are lots and lots of references, but really this newsgroup is about cars not eyes. Jim
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.