ceramic metal halide technology--shock resistant enough?

[uvb4less]

So Ive been a lurker on cpf for years but just now signed up. I am still getting the big red page, even when I try to search, so I don't know if this has been asked before.

Ceramic metal halide technology was proven to improve reaction time of drivers vs. HPS technology. Most agree that this is because of its incredible CRI. Halogen headlamps have somewhat better CRI than the D2S and other HID's we're now seeing, but that is all that they have on HID's, and even that is marginal.

ceramic metal halide technology is only a few years old, and Im thinking that it is not shock resistant enough for automotive applications, I just want others opinions. FYI a ceramic metal halide, in a very course nutshell, is basically the ceramic tube from a high pressure sodium lamp filled with the halide gases found in metal halide lamps. It has a thin metal wire of some sort around the ceramic tube to aid in heat distribution. Indoor greenhouses are already utilizing CMH tech with amazing results, however these are mostly marijuana growers on the west coast as hydroponic tomato houses still enjoy the low cost, efficiency, and red light output of the HPS lamps.

So has anyone heard of ceramic metal halide technology for headlamps? I mainly am interested in the Color Rendering Index. Right now I am trying to get 2 sets of HID lamps (one for fog and one for low beam) with complimentary color rendering profiles to try and get a more complete white light as the end result, but I am unable to find even a spectral power distribution for HID lamps. Any input greatly appreciated.

 

[Norm]

:welcome:

Moved to Transportation Lighting - Norm

 

[Ken_McE]

What you really need is to write to the manufacturer.

 

[uvb4less]

I am not interested in marketing a product though. I just want MY car to have CMH HID's.

What are some other options for high CRI headlights? surely this has been asked before.
Anyone able to find spectral power distribution (spd) for traditional HID bulbs?

 

[ma_sha1]

Never heard of CMH for head lamp, good idea thou.

Here is a 35W HID spectrum, better than Led for sure:

 

[uvb4less]

ma_sha1, thanks so much, that is exactly what I was looking for. I know color temp tells you so little about a light source but do you know which color temp that SPD is from? Do you have more or know where I could get them for 4300 5000 6000 8000K?

 

[-Virgil-]

I'm not sure the SPD presented is for an automotive HID burner, and I don't agree that the SPD of automotive HIDs is "better than LEDs for sure". In fact, the white HB-LEDs being used in headlamps produce an SPD better matched than HID or TH light sources to the response curve of the human eye under mesopic (night driving) conditions; it has been repeatedly found that driver visual performance is better with LED street lighting or LED headlighting than with HID (any variety in actual use) or TH. As for SPDs for 6000K and 8000K light sources...why? Those aren't legitimate automotive headlamp light sources. I don't think CMH is suitable for headlamp use; my understanding is that a CMH burner has translucent rather than transparent walls, so it would be practically impossible to obtain the point-source characteristics needed for effective beam focus.

 

[uvb4less]

I'm not sure the SPD presented is for an automotive HID burner, and I don't agree that the SPD of automotive HIDs is "better than LEDs for sure". In fact, the white HB-LEDs being used in headlamps produce an SPD better matched than HID or TH light sources to the response curve of the human eye under mesopic (night driving) conditions; it has been repeatedly found that driver visual performance is better with LED street lighting or LED headlighting than with HID (any variety in actual use) or TH. As for SPDs for 6000K and 8000K light sources...why? Those aren't legitimate automotive headlamp light sources. I don't think CMH is suitable for headlamp use; my understanding is that a CMH burner has translucent rather than transparent walls, so it would be practically impossible to obtain the point-source characteristics needed for effective beam focus.

The kits sold and used illegally are rated in color temperature. (I am retrofitting acura tsx oem hid projectors to my headlamp housing, which already houses halogen projectors, not reflectors, so my setup after proper adjustment, will be legal)

I have two sets of projectors, fog and low beam, I am putting in a total of four projectors. Some day I may fit LED's to my headlamps, but that is just more than I have time for right now (even though I would LOVE to do such a project).

I am not interested in having yellow fogs. typical HID's have low color rendering in my opinion. CRI is crucial for responsive driving, also my opinion. So with my options, I was hoping to have as high CRI as possible, without inefficient halogen tech.

I was hoping to get two sets of HIDs with complimentary CRI profiles that would provide a more complete white light. (i.e. where one set lacks specific wavelengths/colors, the other would fill these, and vice versa)

This would only require having SPD's of available HID's and comparing them. I would have some high intensity, low power consumption lighting with CRI rivaling leds for a very low time and money investment. Sounds great in theory, not to say that there isnt plenty of variety in aftermarket HID "colors", but being able to find reliable SPD info for each is another story. Thats why I brought it here.

So if anyone knows of HID vendors or manufacturers with SPD charts pls share. Thanks!

 

[uvb4less]

Thanks for the info Scheinwerfermann. I know little about the focusing required for car optics so thanks for clearing that up about CMH. When you say the "walls" of the CMH burner you're referring to the ceramic tube right? That makes sense. Thanks again. Also I like what you said on another thread about the stupid crap people do to cars...black out there brake lights, put hid lights in halogen reflectors, all the other stuff, lol. nothing like passing some oncoming idiot with hids in his halogen reflector low beams.

 

[-Virgil-]

The kits sold and used illegally are rated in color temperature.

That is true, but the "ratings" are meaningless, made-up numbers outside a narrow range. CCT applies only to white light, so calling a yellow light "3000K" or a blue/pink/violet/green light "10000K" or "8000K" or any-other-number-K is as inapplicable as calling a watermelon a garage-door opener.

(I am retrofitting acura tsx oem hid projectors to my headlamp housing, which already houses halogen projectors, not reflectors, so my setup after proper adjustment, will be legal)

If you are removing the lenses or otherwise opening up the housings (except by removing access doors provided for the purpose) then no, your headlamps won't be legal. They'll probably be considerably less technically problematic than "HID kit" retrofits, but legal they will not be.

typical HID's have low color rendering in my opinion.

You're correct. The CRI of automotive HIDs is in the low-mid 70s.

CRI is crucial for responsive driving, also my opinion.

You're not correct. This has been studied extensively and the notion discounted. Remember, facts (when we have done the science to know them) trump opinions. You're welcome to keep hold of whatever opinion you like, of course, in a free country, but that will never change the facts.

So with my options, I was hoping to have as high CRI as possible, without inefficient halogen tech.

You will not get CRI better than low-mid 70s from any automotive HIDs.

I was hoping to get two sets of HIDs with complimentary CRI profiles that would provide a more complete white light. (i.e. where one set lacks specific wavelengths/colors, the other would fill these, and vice versa)

That's a very interesting idea. Unfortunately it is not practical with the HID burners that are actually available.

 

[-Virgil-]

When you say the "walls" of the CMH burner you're referring to the ceramic tube right?

Yes.

 

[uvb4less]

That is true, but the "ratings" are meaningless, made-up numbers outside a narrow range.

As I said before I realize that color temp tells you little about the qualities of a light source, however it is the only "handle" by which I can refer to market options.

If you are removing the lenses or otherwise opening up the housings (except by removing access doors provided for the purpose) then no, your headlamps won't be legal. They'll probably be considerably less technically problematic than "HID kit" retrofits, but legal they will not be.

Again for the sake of brevity I was not specific here, yes I realize that my lights will not be shipped to DOT for a new stamp of approval, I just meant that I am adhering to the guidelines of their law, because in this instance I agree with their judgement.

CRI is crucial for responsive driving

You're not correct. This has been studied extensively and the notion discounted. Remember, facts (when we have done the science to know them) trump opinions. You're welcome to keep hold of whatever opinion you like, of course, in a free country, but that will never change the facts.

Perhaps you are referring to the fact that short wavelength light is more likely to cause disability glare and possibly discomfort glare. In coarse terms this would take blue light out of the desirable CRI. I realize that the human eye sensitivity curve favors green light over blue and red, this would remove more blue and some red out of the light in favor of green in a perfectly color-efficient automotive light, hence lowering the ability to judge lighting in response time based on CRI. But higher color rendering, IN GENERAL, does improve driver response time. Why would anyone believe that whiter light does not improve response time? Here is a study on CMH vs HPS for driver response time in street lighting. http://lrt.sagepub.com/content/39/1/53.abstract
The response time of drivers in CMH lighting (CRI~92) vs. HPS lighting (CRI~21) was remarkable. I don't remember exactly but it was in "seconds" for most speeds, especially in a driver's peripheral field of view. This study prompted many european nations to switch to CMH.
I realize there are other factors in this experiment, but to say that color rendering didn't play a part in these driver's response time would be inane.

You will not get CRI better than low-mid 70s from any automotive HIDs.

I know, HIDs are cheap, powerful, and efficient, but their biggest pitfall as you and I have been saying is their color rendering. Which is why I am asking for spd's of various HIDS, so I can pair two sets, with complimentary color rendering profiles (is this such a difficult project for CPF? I think not, plus there is no shortage of variety on the market) and have High CRI HID lighting.

That's a very interesting idea. Unfortunately it is not practical with the HID burners that are actually available.

What do you mean? Im not trying to reinvent a wheel here. With some easy homwork this could be done. Ive seen some projects on this forum 10x as hard.

 

[-Virgil-]

As I said before I realize that color temp tells you little about the qualities of a light source, however it is the only "handle" by which I can refer to market options.

The only legitimate/legal automotive HID CCTs are nominal 4200 and nominal 5000. Anything else is "no". The 5000K ones produce less light than the 4200K ones. That should make your choice very much easier.

Again for the sake of brevity I was not specific here, yes I realize that my lights will not be shipped to DOT for a new stamp of approval

But no lamps ever get shipped to DOT for a stamp of approval. DOT does not approve items of vehicle equipment.

Perhaps you are referring to the fact that short wavelength light is more likely to cause disability glare and possibly discomfort glare.

No, I'm directly refuting your opinion: CRI of HID headlamps is poor compared to halogens, but that fact has no significant or substantial effect on driver seeing performance at night. That exact question was one of the very earliest aspects of HID headlamps studied rigorously, because it was one of the significant departures from previous headlamps.

And while blue light has been found to increase discomfort glare, it has not been found to increase disability glare.

higher color rendering, IN GENERAL, does improve driver response time.

Sorry, no. The science does not support your assertion.

Why would anyone believe that whiter light does not improve response time?

1. Because there is no such thing as "whiter" light (that is a marketing phrase with no technical meaning), and
2. Because headlamps with lower CRI do not reduce driver visual performance compared to headlamps with higher CRI.

Here is a study on CMH vs HPS for driver response time in street lighting.

Totally inapplicable to the question of headlamp light. Neither of those light sources is used in automotive lighting, and HPS (and LPS) are very nearly monochromatic; they are both grossly deficient in wavelength bands crucial to seeing performance. That is a phenomenon specific to sodium-vapor lighting and it cannot be generalized to apply to any vehicle headlamps that actually exist.

Here are some studies that are germane to vehicle headlamps' color rendering performance:

• In-traffic Evaluations of High-Intensity Discharge Headlamps: Overall Performance and Color Appearance of Objects

• Subjective Preferences for the Red Color of Stop Signs: Implications for the Design of High-Intensity Discharge Headlamps

• Color of Retroreflective Traffic Sign Materials when Illuminated by High-Intensity Discharge Headlights

• Ranges of Stop Sign Chromaticity Under Tungsten-Halogen and High-Intensity Discharge Illumination

• Mercury-Free HID Headlamps: Glare and Color Rendering

That last one includes SPDs for various mercury-free automotive HID light sources. Pay attention to the date of each of these studies as you read them, and you can see the evolving understanding that while color appearance of objects lit by HID headlamps is different than those same objects lit by halogen headlamps, that difference does not reduce driver visual performance.

I know, HIDs are cheap, powerful, and efficient, but their biggest pitfall as you and I have been saying is their color rendering

Actually, no. I have never said that HID headlamps' relatively low CRI is "their biggest pitfall" or anything like that, because the science simply does not support that notion.

I am asking for spd's of various HIDS, so I can pair two sets, with complimentary color rendering profiles (is this such a difficult project for CPF? I think not

The difficulty, as I have said already, is that the complimentary light sources you have in mind do not exist in reality.

 

[uvb4less]

Wow this is way more than I have time for right now but im going to make one final effort to show you what Im referring to,

The only legitimate/legal automotive HID CCTs are nominal 4200 and nominal 5000. Anything else is "no". The 5000K ones produce less light than the 4200K ones. That should make your choice very much easier.

luminous efficacy is not the concern of my post. keep that in mind as you read on. Also if I was worried about getting pulled for having 6000K vs 5000K headlights I wouldnt be modifying my car in the first place.

But no lamps ever get shipped to DOT for a stamp of approval. DOT does not approve items of vehicle equipment.

ok thanks

No, I'm directly refuting your opinion: CRI of HID headlamps is poor compared to halogens, but that fact has no significant or substantial effect on driver seeing performance at night. That exact question was one of the very earliest aspects of HID headlamps studied rigorously, because it was one of the significant departures from previous headlamps.


And while blue light has been found to increase discomfort glare, it has not been found to increase disability glare.

The CRI of HID's vs halogens is negligible. There was a direct comparison between high CRI lighting and low CRI lighting on driver response time, and the results were anything but marginal, especially for obstacles in the peripheral field of vision.


and "it was not one of the significant departures from previous headlamps". I'm pretty sure you're claiming that to driver response time, there is no function of Color Rendering Index (CRI), they are unrelated. I seem to think differently.

Sorry, no. The science does not support your assertion.
1. Because there is no such thing as "whiter" light (that is a marketing phrase with no technical meaning), and
2. Because headlamps with lower CRI do not reduce driver visual performance compared to headlamps with higher CRI.

1. When I say whiter light, Im referring to a higher CRI. The higher the CRI, the whiter a light source appears. This is valid qualitative analysis.
2. I'm not talking about "driver visual performance", but rather "driver response time". None of the 5 studies you mentioned compare driver response time as a function of CRI. If they did they would use light sources with a greater CRI difference for better contrast in the results.
Sorry for posting a pay to read doc, here is a free ad. The very last page has the study Im referring to, notice that CMH, with staunchly different CRI as the comparison, was twice as efficient in lumens per watt, at human response time, than the low CRI comparison. If you don't like the ad then pay for the full study previously cited. http://sorang.nu/belysning/Outdoor Mesopic white light.pdf

Totally inapplicable to the question of headlamp light. Neither of those light sources is used in automotive lighting, and HPS (and LPS) are very nearly monochromatic; they are both grossly deficient in wavelength bands crucial to seeing performance. That is a phenomenon specific to sodium-vapor lighting and it cannot be generalized to apply to any vehicle headlamps that actually exist.

Let me ask you, what makes a light source superior for driving in your opinion? you say "wavelength bands crucial to seeing performance", yet you dont acknowledge that higher CRI equates to better response time. What are those "Wavelengths" you speak of anyway?
You're marginalizing the fact that CRI does have an effect of driver response time (not something in question in the sci. com. as it has been scientifically proven, the results are improving driving conditions already). CMH and HPS have similar luminous efficacy (brightness), in lm/wt, however the most notable difference is their CRI, (~23 vs ~92; on a x/100 basis) This has been made evident with the studies aforementioned. The fact that you tested HID's, with 2.5x the light, at a marginally different CRI (~70 vs ~82 ), against halogens, with 20% the luminous efficacy of HIDs, and had equal response time (a variable not even mentioned in the lengthy studies you quoted), means little to me. That is obviously a way bright light source, a major factor in the study youre referring to.

The difficulty, as I have said already, is that the complimentary light sources you have in mind do not exist in reality.

the complimentary light sources dont exist? what do you mean? indoor greenhouses do this all the time--it's not rocket science. If one source has high output at 540-560 nm, but lacks 560-580nm, and another source is vice versa, mission accomplished. I dont have any more time to argue this point with you. If I want to think that markedly higher CRI allows me to respond quicker (especially to objects in my peripheral field of vision, as has been scientifically proven) than a light source with markedly lower CRI, let me continue in my delusion.

 

[Alaric Darconville]

If I want to think that markedly higher CRI allows me to respond quicker (especially to objects in my peripheral field of vision, as has been scientifically proven) than a light source with markedly lower CRI, let me continue in my delusion.

Except that your delusion can get someone killed. Maybe you, maybe Scheinwerfermann, maybe me, or maybe your passenger and the driver of the other car, or the guy changing his tire in the rain on the side of the highway.

Like any delusion, it worsens when it becomes evangelical, and then more converts to the falsehood go out and modify their cars, thinking the marketing geniuses that came up with this stuff weren't just blowing smoke, and had somehow come up with something that not even the car companies, with their huge R&D budgets, and a Congress in their pockets, couldn't come up with. The roads get unsafer and unsafer, thanks to people doing these things.

This is valid qualitative analysis.

Which is not nearly as valid as a quantitative analysis.

 

[Alaric Darconville]

response time vs. visual performance

The difficulty, as I have said already, is that the complimentary light sources you have in mind do not exist in reality.

the complimentary light sources dont exist? what do you mean? indoor greenhouses do this all the time--it's not rocket science. If one source has high output at 540-560 nm, but lacks 560-580nm, and another source is vice versa, mission accomplished. I dont have any more time to argue this point with you. If I want to think that markedly higher CRI allows me to respond quicker (especially to objects in my peripheral field of vision, as has been scientifically proven) than a light source with markedly lower CRI, let me continue in my delusion.

Perhaps not rocket science, but it may be photonics or optics.

In a greenhouse, the light is not focused in such a way to allow the gardener to see objects 150' away, without blinding another gardener on the other side of the greenhouse attempting to transplant seedlings.

With headlights, to get those complementary light sources to blend in to one beam, which meets the photometric requirements of a good headlight is rather difficult indeed. It would seem that by necessity it would require two discrete burners, so that the focal points of each are considered and then collimated or otherwise blended together. The different wavelengths will be refracted differently in lenses, and so there must be quite a bit of precision.

There's no point to doing any of that, however, as it has been studied and evaluated, and the facts are the facts: CRI is not that important.

I'm not talking about "driver visual performance", but rather "driver response time". None of the 5 studies you mentioned compare driver response time as a function of CRI. If they did they would use light sources with a greater CRI difference for better contrast in the results.

One should be less concerned with "driver response time" if that comes at a detriment to "driver visual performance". Reacting more quickly, but then making the wrong decision at that time due to poor visual performance can be deadly. Sure, "he who hesitates is lost" -- but, "look before you leap".

I'm also not convinced that differences in CRI can result in better contrast-- my old B&W set has a contrast knob, and the CRI is essentially 0 no matter what that knob is set for.

 

[-Virgil-]

Wow this is way more than I have time for

You may want to make time. You are trying to improve your vehicle's headlamps, which is a reasonable goal, but you're assuming that what you believe you understand about stationary lighting applies to headlamps, and that's not the case. You stand to waste a great deal of time and money, and wind up with unsafe headlamps, if you don't first take (make) the time to learn about headlamps.

luminous efficacy is not the concern of my post

Who said anything about luminous efficacy…? What I said was the 5000K burners produce less light than the 4200K burners. That's a fact, and it substantially affects the safety performance of the headlamps in which the burners are installed.

The CRI of HID's vs halogens is negligible.

Er…no, that's not correct. Halogens have 99+ CRI. Automotive HIDs have low 70s. That's a very large difference. Even so, it has been shown to have no significant effect on driver performance at night, so effort spent trying to conjure up a particular CRI with your headlamps is largely wasted. Which doesn't necessarily mean you shouldn't do it if it's something you want to do just to be able to say and show that you did it. But it's not going to improve the headlamps' real performance in terms of how well they allow you to do the driving task at night.

and "it was not one of the significant departures from previous headlamps".

Yes, it was. All headlamps prior to HIDs had CRI of 97+. HIDs have low 70s.

1. When I say whiter light, Im referring to a higher CRI.

That is not an accurate definition for CRI. Not at all, not even close. CRI describes how accurately colors are rendered relative to a standardized, formalized rendering. It doesn't have anything to do with the appearance of the light itself or whether it's warm white, cool white, etc.

The higher the CRI, the whiter a light source appears.

No, sorry, incorrect. You seem to be almost describing CCT (correlated color temperature), but even if we substitute CCT for CRI, your claim still doesn't square with reality.

2. I'm not talking about "driver visual performance", but rather "driver response time".

Driver response time is wholly subsumed under the rubric of driver visual performance. Please go and read all the linked studies and spend some time thinking about what they say; even if you continue not to understand most of what you are reading, you ought to be able to pick up at least the beginnings of a working knowledge of the science in this field.

Let me ask you, what makes a light source superior for driving in your opinion? you say "wavelength bands crucial to seeing performance"

That's right.

yet you dont acknowledge that higher CRI equates to better response time.

Because it doesn't. Please stop trying to contort findings from street light studies so they fit your guess at what makes an ideal headlamp; the two lighting tasks are a good bit more different than they might seem just based on common sense.

The fact that you tested HID's, with 2.5x the light, at a marginally different CRI (~70 vs ~82 ), against halogens

Er…wow. You not only are misinformed on the CRI of halogens (99+, not "~82") but you seem either not to have read the studies or to have utterly failed to comprehend them. Please read them again, however many times is necessary to grasp their methods and findings. Moreover, when and if you come to understand them, please note that whatever contention you may have with their methods or findings lie with the researchers, not with me.

the complimentary light sources dont exist? what do you mean?

Well, I thought it was pretty clear: you are seeking bulbs with particular SPDs for installation in your headlamps. Bulbs with the particular SPDs you want may or may not exist for various stationary lighting applications -- greenhouses, street lights, etc. -- but they do not exist for headlamps.

If I want to think that markedly higher CRI allows me to respond quicker (especially to objects in my peripheral field of vision, as has been scientifically proven) than a light source with markedly lower CRI, let me continue in my delusion.

No. You are entitled to your own opinions, but not to your own facts.