Adaptive Headlights

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bfd wrote:

Well, sure, in that there's a glowing filament in a halogenated atmosphere. The reason why their luminous efficacy is so much higher is the infrared-reflective nature of the envelope (glass). See my post in response to Sexton.

I spent quite a bit of time on the phone and in front of the computer (and at the post office) contributing to that article. It came out pretty well, even the parts I didn't help with ;-)

Sylvania Silverstar bulbs are a scam, just like all the rest of the blue-glass "extra white" bulbs. They produce less light over a shorter lifespan, at a premium price, all in exchange for an abstruse, marketeer-fabricated notion of looking "cool". See data at http://tinyurl.com/hlwvq
DS
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Richard Sexton wrote:

HIR2, 31 to 33 lumens per watt HIR1, 36 to 39 lumens per watt
For comparison:
H1, 24 to 26 lumens per watt HB4 (9006), 17 to 19 lumens per watt

Spherical bulb glass rather than tubular, with multilayer dichroic coating that reflects IR and passes visible light. Filament at centre of sphere, so IR is reflected back onto filament, heating it up hotter than it can be heated by a given electric current, giving greater luminance without the sharply negative effect on filament life that comes with increasing luminance by means of increased wattage.
DS
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Have you ever driven a car with HID lighting? You very soon don't notice the *slight* difference in colour temperature if you've got 4300k lamps.

No it's not. I've driven a car with a conversion and it was fine - although of course illegal in the UK. But then so are greater than 55 watt halogens for dips.

It's anything but young - the technology has been used in film etc lighting for many years.
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Of course not. Under warm white fluorescent or 7500K daylight or even gro-lux your eyes gets used to it and seems "normal".
The complaints piling up at NHSTA about oncoming HID dazzle tell another story though, they're damn annoying. In Yurrup yo uhave to have leverlers just to address this problem which are not required here.

What kind of conversion?

HID lamps are indeed not new, but they are very much so in automotive applications which is what I was referring to. "white" HID lamps are reaonably new, previously only mercuty (very blue) and sodium (very yellow) were available.
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You really think a lamp with a colour temperature far removed from daylight is going to be used as a daylight substitute or fill in filming?
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Uh, no. That's why I didn't say that. HID lamps have been in use as street lights for decades. Low and high pressure sodium are usually used because they have the longest life. How often you change the bulb is a big deal when they're way up there. Mercury is ususally used where the amount but not color of light is important. They spike madly in the blu end of the spectrum.
HQI/Halide lamps have been around for "only" abot 30 years and are more or less "white".
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Dave Plowman (News) wrote:

That's because of what Richard said: The automotive HID burner must be hammered VERY hard to reach its full intensity as quickly as it does, and that length of time is still around 60 seconds. The Xenon present in automotive HIDs is there so that they will produce light immediately upon switch-on, which is a legal requirement.

True, but it's important to remember that this is a *light source* efficiency advantage. It does not necessarily translate to a *headlamp* efficiency advantage. It's still down to the optical engineers, stylists and beancounters (not always in that order!) to determine how efficient the lamps will be. As mentioned in a previous post, there are good and bad HID and halogen headlamps. A good one of either type is preferable to a bad one of either type.
DS
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Dave Plowman (News) wrote:

Common mistake. The best present LED headlamps give performance nearly equal to the low-end HID systems, with **double** the power consumption of an HID system and triple the cost. The power consumption and cost will decrease with time, but it is an error to conflate the characteristics of high-power illumination LEDs with those of low-power signalling LEDs (e.g. the little green, red and blue indicators on your electronic equipment, dashboard, etc.). Too, the system power is increased by the necessary forced-air ventilation. Remember, LEDs produce significant heat on a per-lumen basis, and instead of being cast forward with the light beam, this heat is cast rearward at the junction. The heat must be exhausted from the rear, else overheat the junction, dropping light output significantly and threatening the structural integrity of the lamp housing. At the same time, heat must be supplied to the lens of an LED headlamp for melting snow, ice and condensation fog. This usually entails electric heating, which further ups the system power consumption.

Not likely. Over 75% of the new-vehicle fleet in the first world are still factory equipped with tungsten-halogen headlamps, and while HID and LED headlamps will gradually increase their market share, they are unlikely to comprise a majority of headlamps on the road in the foreseeable future.
DS
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I'd say you have a rather typical view from some that the energy consumption of car lighting doesn't matter.
Automotive makers the world over have been proved to pay scant attention to such things until pushed into it by legislation, etc.
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Dave Plowman (News) wrote:

Oh, would you? Well, me, I'd say I didn't see you at the V.I.S.I.O.N. automotive lighting research and development symposium last week in Rouen. And, come to think of it, I don't recall seeing you at the GRE (Groupe de Rapporteurs d'clairage, the UN international working group on automotive lighting regulation) meeting in Geneva or ISAL (International Symposium on Automotive Lighting) in Darmstadt last autumn, or at any of the National Academy of Sciences Transportation Research Board annual conferences over the last five years. I'm sure you attended at least some of these...right? So, you would've participated in at least some of the same roundtable discussions, heard some of the same paper presentations, gone on some of the same night demonstration drives, reviewed some of the same data, spent time talking with the same researchers, regulators, scientists, R&D chiefs...
...oh, you weren't at any of those? Fancy that.

Mm.
DS
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Fine. And you still say the tungsten bulb will be with us forever? Have you not considered the safety angle of replacing them with LEDs for tail lights, etc?
When discharge headlights first appeared they were a rare and expensive option on luxury cars. Now you'll find them available on shopping hatches. It doesn't take too much foresight to see the price dropping 'till they are standard on most cars. Might not be good news for aftermarket sales of headlights etc, though.
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Dave Plowman (News) wrote:

Please don't put words in my mouth-wait til after the first date, thanks.
But the filament lamp will be with us for a very long time to come. In this field, old technology has a tendency to hang around for many years after the introduction of newer technology aimed at replacing the old.

I have indeed, and I've written on it extensively. Your point...?

The series-production introduction of discharge headlamps was about 15 years ago. Market penetration worldwide hovers at around 20% overall (lower in North America, a little higher in Europe, a lot higher in Japan).

Actually, what's more likely to occur is that LED headlamps will cross the cost-effectiveness barriers before HIDs do. It's easier to foresee a worldwide market in 2 decades' time consisting of perhaps 40 to 60 percent tungsten-halogen, 15 to 25 percent HID and the rest LED.
DS
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Let me remind you of what you wrote in reply to me:-
*************************
DP the sure thing is the tungsten filament bulb's days are numbered.
DS Not likely. Over 75% of the new-vehicle fleet in the first world are still factory equipped with tungsten-halogen headlamps, and while HID and LED headlamps will gradually increase their market share, they are unlikely to comprise a majority of headlamps on the road in the foreseeable future.
*****************
Either their days are numbered or they'll last forever. Which is it?
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Dave Plowman (News) wrote:

Foreseeable future != forever.
DS
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Both. New cars will migrate away but it is also true that filament lamps will always be around for older cars.
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Maybe with headlights, but other bulbs could be replaced with low energy long life types when they fail.
I dunno about the US, but in the UK it's common to see older cars with many of the rear lights, etc, not operating. The use of quality well designed LEDs, more attention to grounding rear lights properly and 'hard' wiring to the bulbs should end this as they should last the life of the car.
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Therefore incandescents will always be around. They still make buggy whips too (just not very many).

Yeah I had a British car once too.
(I'm in Canada BTW, not the US; although I lived in LA for a decade I preferred Canada. I'm also the evil bastard that convinced Stern to move to Canada; he lives a couple of hours from me)

Yeah, ABOUT that. The first time I saw a real LED work back in the 70's I looked at it and thought "man, this is gonna change everything". 30 years later they show up in some flashlights and as 18-wheeler taillights. I'm still waiting. There isn't one single drop in replacement LED signalling bulb I'm aware of and while it may happen in time, that time aint yet.
And then you have the purists. These are the guys for which not only does the bulbs have to be correct it has to be exactly the same as the one the factory shipped it with, all markings intact etc. I do realize it's a very niche market but you're not gonna win a concours with a batwing CSL or Gullwing with LED taillights.
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Which really is what I meant.

;-) Perhaps it's the fact that old Japanese cars go on and on that leads to so many rear lamp problems.

Ah - that's the best way. No motor makers to create myths round.

There are 'drop in' types, but not E marked so not legal in Europe - although this may change. Although rather the same applies as using discharge types in a lamp unit designed for tungsten - the optics aren't optimised for an LED substitute.

Indeed. My comments referred to what is likely to happen in the near future with new production.
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Dave Plowman (News) wrote:
[LED replacements for existing vehicle lamps]

Won't. "LED bulb" retrofits are not safely usable *not* just because they lack an E-mark, but because they are fundamentally incompatible with optics designed for use with a filament bulb. It's not a question of "optimisation", as you stated. It is a question of fundamental optic design, and the output characteristics of LEDs differ so radically from those of filaments that a drop-in "LED bulb" replacement is just not physically possible right now.
About 10 days ago, I had dinner with Osram Optoelectronics' LED R&D chief, and we discussed in detail the question of an LED device to directly and effectively/safely/legally replace a standard filament bulb. He's thought about this question at great length, and done a great many experiments and studies. At the **CONCEPTUAL** level, it could theoretically be done using a Lambertian-emitting LED powerhead (this is the side-and-rear emitting type which has the same surface luminance regardless of the angle of view -- in contrast to the conventional "straight ahead" emitters which produce a spot beam facing straight away from the emitter). The powerhead would have to be engineered such that its surface luminance and far-field illuminance are within the 90th percentile tolerance of the luminance and illuminance of the specific filament bulb one wanted to replace, *from all polar angles*. For a P21W or P21/5W replacement, this would take an estimated 10,000 man-hours of R&D because no existing product even remotely approaches the 90th-percentile tolerance range relative to P21W or P21/5W. The R&D chief estimated this would begin to become an economical product to develop at high OEM volumes of around 10 million, which defeats the point of developing such a device, because at that point it becomes more economical to develop a new LED solution independent of what went before, i.e., we discard the notion of backwards compatibility with filament bulbs. There is an existing first-generation Lambertian-emitting LED powerhead, the Osram Joule, http://ledsmagazine.com/articles/news/2/6/26 . It is used in the current Mercury Mountaineer SUV in the North American market. An optical system (lens and reflector) can be designed that will produce compliant performance from either a Joule LED or a conventional bulb, **If contemplated from the lamp design stage that there will be bulb and LED versions of the lamp**. He has spent many hours testing Joule LEDs in pre-existing bulb-type optics-he has specially-modified Joule powerheads that can be moved axially to correct the focal length for whatever lamp reflector is being tested. He mounts them in an axial micromanipulator and finds the optimal placement of the powerhead. He has found a compliance rate of a little under 50%. That is, with the state-of-the-art LED emitter, he can make about half the bulb-type lamps he tests produce minimally compliant photometry. There's no predictability to it; some lamps that are conceptually identical but stylistically different will give different pass/fail results. And, the compliance success rate is helped by the relatively low intensity requirements for ECE-spec vehicle exterior lighting devices relative to North American-spec items. US amber rear turn signal intensity requirements are 130-750cd, ECE requirements are much lower at 45-180cd. Likewise, a US brake lamp is 70-300cd, while an ECE brake lamp is much lower at 54-167cd. So, the minimum permissible intensity of ECE brake and signal lamps is between 35% and 77% of the minimum permissible US intensity. Where overall intensity is a limiting factor in LED retrofit success, these numbers are significant.
But all of this is theoretical right now. The "LED bulbs" presently available consist of a cluster of axial-emitting LEDs grafted onto a bulb-type base, and they are not only without E-mark, they are physically without hope of producing even barely minimally adequate safety performance. The result of using such an "LED bulb", under the best of conditions, is a 25mm spot of insufficiently intense light. Distribution and intensity of light through the required vertical and horizontal angles, and dispersion across the required minimum projected effective surface area, is not even remotely approached. And yes, this applies to the fancy/expensive "deluxe LED bulbs" with side-facing as well as rear-facing emitters, too. So, no, your guess that the legality of these devices "may change" has no basis in fact.
DS
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It's most sensitive to green of the three primaries. But more sensitive at the blue than red end - at either side of the roughly centre green. We're used to tungsten filament lamps being towards the red end of daylight - which is probably why many HID types look blue in comparison. If all lights were HID of the same colour temperature they'd soon look the norm.
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