# If I was in charge of automotive lighting



## TigerhawkT3 (May 5, 2007)

I would make the brake lights, blinkers, and reverse lights all LED, and I would use a single HID headlight that turned with the steering wheel. I see burnt out brake lights (and headlights too, for that matter) far too often.

How about you?


----------



## sejvaar (May 5, 2007)

I'd put machine guns and rockets that fire fore and aft...oh wait...lights...nevermind.


----------



## Flummo (May 5, 2007)

I'm with you for the LEDs, but one single HID is absolutely a no-no in my book. One (or more, I wouldn't mind) HID at each front "corner" of the car shows other cars how wide the car is in the dark and gives oncoming traffic a good idea about how far away it is. One single light seems to make people automatically think it is a motorcycle, or even worse a moped. Driving at 100+kph/60+mph at night and being mistaken for a moped doing 30-45kph is NOT something you want to happen.


----------



## Diesel_Bomber (May 5, 2007)

I like my halogen high-beams. They don't mind being turned on and off frequently and at short intervals, and don't limit lumen output the way merely uncovering a section of the low(hid) beam would.

I also don't at all like the idea of only having one headlight. In addition to Flummo's comments, imagine if that one headlight burnt out? In the city or on a well-lit interstate it wouldn't be such an emergency. However, I live out in the country, there are no street lights out here. If my ONE headlight fails it could kill me.

Safe and comfortable driving requires many different kinds of lighting. You wouldn't ask one singular flashlight to provide 1.) an enormously bright scorcher beam, 2.) another beam that's a compromise between seeing well yourself and not blinding others, and 3.) a low,wide beam for bad weather. You shouldn't ask one headlight to do the same thing.

:buddies:


----------



## Sub_Umbra (May 5, 2007)

How about me?

I love an idea I read about 30 years ago...Put *hidiously powerful* headlights behind polarized lenses with the polarity _exactly the same for each headlight in every car._ (Say 45° clockwise from verticle) Then install windscreens in each car that would be polarized exactly like the headlights. 

IMO this would be the best of both worlds. You could have much, much, *much* brighter lights than you may use now, because the polarization of all headlights coming towards you would be a full 90° out from the polarization of your windshield -- and thus be cancelled out. Your's would always look *very bright* and his would always look *very dim.* 

Perhaps the filters could be only 85° out of phase to make oncoming cars easier to see. Whatever. Apply a polarized film to old windscreens for transitional compliance. Or the drivers of non-compliant autos could wear polarized glasses that would do the same thing. Let someone else work out the details -- policy is the fun part, anyway. 

EDIT: I'd polarize the rear view mirror to knock down the guy's lights behind you somewhat, too.


----------



## tebore (May 5, 2007)

Sub_Umbra said:


> How about me?
> 
> I love an idea I read about 30 years ago...Put *hidiously powerful* headlights behind polarized lenses with the polarity _exactly the same for each headlight in every car._ (Say 45° clockwise from verticle) Then install windscreens in each car that would be polarized exactly like the headlights.
> 
> ...




Quick question.

Wouldn't the lights from your car that's at 45 and your windshield at 90 cause the problem of blocking the light from your headlights making your lights just as dim?


----------



## Sub_Umbra (May 5, 2007)

tebore said:


> Quick question.
> 
> Wouldn't the lights from your car that's at 45 and your windshield at 90 cause the problem of blocking the light from your headlights making your lights just as dim?


No. The polarization for the winshield would be exactly the same as the headlights and _the polarization of *all* car's headlights *and* windshields -- would be oriented the same way,_ like the top square in the pic below.





It's only when other cars are turned around _and pointed at you_ that their lights would be attenuated. Then their polarization would be like the bottom square -- out of phase with your windshield.

EDIT: The only polarization that would not be like the top square in the pic would be the *rear view mirror* which would be like the bottom square, so you wouldn't be blinded by headlights behind you. Now that I think about it, the rear window would probably require some kind of compromise polarization setting, also -- or perhaps _in lieu_ of rear view mirror polarization. Oh well, like I said before, that would be something for the _detail people_ to work out.


----------



## tebore (May 5, 2007)

I think I have a better idea of how it works now. I couldn't wrap my head around it before. Why would you need the polarization of the rearview when you can just get those self dimming ones?


----------



## Sub_Umbra (May 5, 2007)

tebore said:


> I think I have a better idea of how it works now. I couldn't wrap my head around it before. Why would you need the polarization of the rearview when you can just get those self dimming ones?


My original thought (if that's even possible ) would be that every car's lights would be maybe *five times* as bright as they are now. That would probably overpower the adjustable rear view mirrors. Now that I've thought about it some more I realize that this would have to be dealt with by polarizing the whole rear window -- otherwise no matter how well any rear view mirror scheme worked there would *still* be this incredible blast coming from behind you (sorta like the sun) that would be blowing back from _every surface_ in front of the driver. That's the real deal -- the idea that nighttime driving lights could actually be 4 or 5 times brighter -- and how do we make *that* happen.

It's not my idea but I think it's really cool. If there was a car beside you you'd be able to see what his lights lit up -- just like you can now, but the lights of everyone coming towards you would be severely attenuated.


----------



## PhotonWrangler (May 5, 2007)

I remember reading an article a few years ago where some designers were considering using a single, really bright light engine and piping the light to the various locations using fiber optics and shutters. This was before LEDs started coming into their own for turn signals, dashboard indicators and now headlights.

I'm personally not entirely sold on the idea of LED headlights yet, at least not until the color rendering gets a little better.


----------



## 2xTrinity (May 6, 2007)

Sub_Umbra said:


> No. The polarization for the winshield would be exactly the same as the headlights and _the polarization of *all* car's headlights *and* windshields -- would be oriented the same way,_ like the top square in the pic below.
> 
> 
> 
> ...


Regardless of orientation, a polarized filter will block out HALF of all incoming _un_polarized light. In the case of sunglasses, this is fine -- blocking half of all light, and selectively blocking a grater percentage of light reflected off of shiny surfaces (all without distorting colors) is pretty much ideal. For driving a car at night though, you need as much light coming through as you can get. With a polarized windshield, you'd have to light up the entire road surface to _double_ the brightness to see it as well as before. Meaning you'll need to quadruple the brightness of the headlights, double the brightness of the street lights, and double the brightness of the moon to see as well as before.

The headlights bulb lumens need to be quadrupled as your your own filter will waste half of the light being produced, and your windshield will waste another half of that. Realistcally, since not all polarizing filters are ideal (meaning, _less_ than half of unpolarized light will get through) your headlights would need to produce five times the light to have the same visibility. That means the filters on your own headlights would be absorbing about 60% of the wattage of your headlights (Look up the video of a flashlight setting newsprint on fire in two seconds to see the effects of that) 

Also, any poor sap who doesn't polarize his windows will be assaulted with double the amount of glare as before...



> EDIT: The only polarization that would not be like the top square in the pic would be the *rear view mirror* which would be like the bottom square, so you wouldn't be blinded by headlights behind you. Now that I think about it, the rear window would probably require some kind of compromise polarization setting, also -- or perhaps _in lieu_ of rear view mirror polarization. Oh well, like I said before, that would be something for the _detail people_ to work out.


The problem with this is that light reflected off of the road -- what you're actually trying to see -- will be at a random orientation (50% of it oriented correctly, thus able to pass through your filter, the other 50% being lost)

Of course, having only a polarized rear view mirror (and not a polarized windshield) does mean that you'd only need to double the double your headlight's power, not quadruple them. But that doesn't help with filtering head-on glare. Either way though, you still have to deal with finding a filter that can dissipate huge amounts of heat, and you'd still have additional alternator load (many modern car's electrical systsems are overtaxed as it is), and this system would be worthless anyway unless every single car on the road decides to adopt it.



> I remember reading an article a few years ago where some designers were considering using a single, really bright light engine and piping the light to the various locations using fiber optics and shutters. This was before LEDs started coming into their own for turn signals, dashboard indicators and now headlights.


Sounds like a really dumb way to do it. The light piping will waste a huge amount of light. Also, the huge light source will need to be on all the time, carrying with it significant overhead, even if only a fraction of the lights need to be on, the "shutters" will only serve to waste light, rather than actually represent turning the light off. Also, that all sounds like it would take up even more space and cost even more than present-day reflector assemblies.

IHMO LEDs, or a whole bunch of separate, independently controllable light-sources is a much better approach -- they can be surface mounted, thus take up less physical space, and be more efficiently directed using optics. (rather than a single point source, a reflector, and lots of matte black "shades" to block unwanted spill) They also are less likely to burn out, but even it one does, it's no big deal. You don't have a single point of failure like using one massive light source (going from 100% light, to NO light due to a single failure is a severe safety danger). Of course, I think LEDs should still be designed to be swappable, as they could still burn out due to a defective part, or even in accident (hit with a rock) or something, instead of throwing away an entire assembly over one bad LED.

hough they should still be designed to be swappable like regular bulbs (rather than replacing an entire fixture) incase some are messed up in an accident are something. 



> I'm personally not entirely sold on the idea of LED headlights yet, at least not until the color rendering gets a little better.


LEDs have the potential to have better color rendering than anything else. There have already been LEDs made with 98CRI at 4000K -- essentially an ideal light source, too bad it's not available on the market. What will be needed is either a two-phosphor design, or an RGB-based design. The RGB I think would be the best way to go -- a 4000K color temp (what good HID lights are) could be used most of the time. In the fog, the driver could simply "turn off" the blue component -- as blue is what gets reflected and scattered the most in fog (this is why fog lights have amber filters). 

High beams/low beams could be much more elegantly designed by having a bank of higher-angle LEDs that are switched off and on electronically, rather than dual-filaments (incandescent high beams), or movable optics (HID high beams). I believe there have even been talks of designing LED head lights to "detect" oncoming cars, and selectively dim certain emitters to cut down on glare.


----------



## Sub_Umbra (May 6, 2007)

2xTrinity said:


> Regardless of orientation, a polarized filter will block out HALF of all incoming _un_polarized light. In the case of sunglasses, this is fine -- blocking half of all light, and selectively blocking a grater percentage of light reflected off of shiny surfaces (all without distorting colors) is pretty much ideal. For driving a car at night though, you need as much light coming through as you can get. With a polarized windshield, you'd have to light up the entire road surface to _double_ the brightness to see it as well as before. Meaning you'll need to quadruple the brightness of the headlights, double the brightness of the street lights, and double the brightness of the moon to see as well as before.
> 
> The headlights bulb lumens need to be quadrupled as your your own filter will waste half of the light being produced, and your windshield will waste another half of that. Realistcally, since not all polarizing filters are ideal (meaning, _less_ than half of unpolarized light will get through) your headlights would need to produce five times the light to have the same visibility. That means the filters on your own headlights would be absorbing about 60% of the wattage of your headlights (Look up the video of a flashlight setting newsprint on fire in two seconds to see the effects of that)
> 
> Also, any poor sap who doesn't polarize his windows will be assaulted with double the amount of glare as before...


Is that what I said?...or is that what you said? Anyone may scroll up to see...As far as quadrupling the brightness goes...do you think that that could have anything to do with my recommendations to *do exactly that?* ...for those capable of scrolling up? DUH! Whatever blows your dress up! If you dissagree, just answer my post -- _don't just post *beyond something* I never posted._ When you criticze another's post you should probably *read it first* :


Sub_Umbra said:


> ...the idea that nighttime driving lights could actually be 4 or 5 times brighter -- and how do we make *that* happen.


So, given what I've already posted, *and now showed you twice,* what is it that you don't understand?

As far as your references to streetlights and other *incredibly simple matters* go I would say that even the _Detail People_ would have no trouble polarizing those lights, since traffic moves in very predictable patterns. I mean really, if we are dealing with a one way street, _even most city employees_ would probably be able to eventually figure out which way polarization filters would work on a given streetlight. If that seems cruel I would remind readers that it was *your post* that suggested that this task was impossible for city employees. The road crews in my city are smarter than that...and in my city that's no mean feat.

As far as your references to non-compliance goes, the more lucid among us _who know how to scroll up to previous posts_ will know that my initial post provided for them -- even though such detail was not called for in the Subject line or Original Post. *Yet another reason* to learn how to scroll up and review!

Have you ever played with polarizing filters? I mean *in your own hands...*and not just theorizing about what they would be like *if you did?*


----------



## tebore (May 6, 2007)

Most modern car electrical systems are taxed to the max as it is today. Engineers working on modern cars are acting like that guy in Apollo 13 trying to squeeze every amp. There's talk about moving to a 32volt(or was it 48)electrical system to help out. There's ideas of also making the alt apart of the liquid cooling loop or dual Alts like in some RV's.

Self dimming headlights have been around since the 1950's it just disappeared for while. I believe the Chevy Bel-air and Caddies had it in that period. I guess their lights were already so dim that a self dimmer was almost useless.


----------



## 2xTrinity (May 6, 2007)

> Is that what I said?...or is that what you said? Anyone may scroll up to see...As far as quadrupling the brightness goes...do you think that that could have anything to do with my recommendations to do exactly that? ...for those capable of scrolling up? DUH! Whatever blows your dress up! If you dissagree, just answer my post -- don't just post beyond something I never posted. When you criticze another's post you should probably read it first


The first time I read that I thought you were referring to quadrupling the apparent brightness (what the driver would see after all the filtering) not the lamp wattage, and that such an increase could be justified as the filters would prevent that extra light from blinding other drivers. That is true. I do apologize for coming across incredibly harsh in that post though, 



> As far as your references to streetlights and other incredibly simple matters go I would say that even the Detail People would have no trouble polarizing those lights, since traffic moves in very predictable patterns. I mean really, if we are dealing with a one way street, even most city employees would probably be able to eventually figure out which way polarization filters would work on a given streetlight. If that seems cruel I would remind readers that it was your post that suggested that this task was impossible for city employees. The road crews in my city are smarter than that...and in my city that's no mean feat.


I wasn't suggesting that the streetlights be polarized, simply that they'd need to be brighter in order for them to be as effective if everyone is driving using filtered glasses or a filtered windshield. My point really has more to do with the whole idea not being worth it due to increases in light pollution/power consumption, rather than it not being possible.



> Have you ever played with polarizing filters? I mean in your own hands...and not just theorizing about what they would be like if you did?


I've done plenty of playing around with polarized filters, including using them to attenuate polarized lasers for optics exeriments, and working with regular non-coherent light. I also wear polarized sunglasses every single day.


----------



## petersmith6 (May 6, 2007)

why dont you take a look at some european cars.there head light wether HID or filament are Far better than US cars.its all a case of optics and reflecter design.with our higher speed limits they had no optionm but to improve them.the Citroen SM and DS had steering driving lamps in 1967.well all except the ones for the US market....some federal idiot banned them.leds indicaters and and break lights are nothing new for BMW and Mercs.just the US goverments a little SLOW


----------



## TigerhawkT3 (May 6, 2007)

I can't believe I forgot about redundancy, high beams, and car/moped differentiation. Silly me.

Still, I like the idea of having LEDs wherever possible. They can't be PWM, though - it really bugs me when I turn my head to look around only to get hit with a blinky flickery effect from someone's PWM brake lights.


----------



## 2xTrinity (May 6, 2007)

TigerhawkT3 said:


> I can't believe I forgot about redundancy, high beams, and car/moped differentiation. Silly me.
> 
> Still, I like the idea of having LEDs wherever possible. They can't be PWM, though - it really bugs me when I turn my head to look around only to get hit with a blinky flickery effect from someone's PWM brake lights.


I think if an LED system is going to use PWM, an extremely high frequency (say 20kHz like modern fluorescent lamps) should be mandatory. I believe the PWM prevents any color shift which might happen due to current-dimming.


----------



## TorchBoy (May 6, 2007)

2xTrinity said:


> The headlights bulb lumens need to be quadrupled as your your own filter will waste half of the light being produced, and your windshield will waste another half of that.


No it won't. It'll let through everything because the polarisation will be exactly what it wants. The headlamp still needs to be four times as bright, though, to get the same illumination range (being inversely proportional to the square of the distance).

A few simple, small sensors with variously angled polarising filters in front of them will easily sort out what angle light is being received - the one receiving the most light gives the angle of incident polarised light, if any - and thus what angle the windscreens/mirrors should be tuned to, which can be done on the fly using liquid crystal technology.



TigerhawkT3 said:


> I can't believe I forgot about redundancy, high beams, and car/moped differentiation. Silly me.


Glad you got that sorted out. :goodjob: I had a few "But..." issues to your original post until the on-to-it early posts from Flummo and Diesel_Bomber.


----------



## RustyKnee (May 8, 2007)

all this talk of polarised lights....am I going to need polarised sunnies when riding my bike at night? lol....not mention i,'ll need even brighter lights to be seen.

led headlights will give car designers some funky freedoms. not tied to having 2 big old lamps in the same place....I want my lights in the shape of the big dipper hehe

Stu


----------



## 2xTrinity (May 8, 2007)

TorchBoy said:


> No it won't. It'll let through everything because the polarisation will be exactly what it wants.


In the first case, the light from the filament or arc (HID) will be unpolarized, meaning half of it will be rejected by the filter. 



> A few simple, small sensors with variously angled polarising filters in front of them will easily sort out what angle light is being received - the one receiving the most light gives the angle of incident polarised light, if any - and thus what angle the windscreens/mirrors should be tuned to, which can be done on the fly using liquid crystal technology.


If the polarization angle of the windshields will change, then that defeats the entire purpose of using them to block glare from oncoming headlights. The idea is to block light polarized opposite the filter (direct glare) but not block the target being viewed. Unfortunately, the light coming from the target you're trying to see, which might _not_ be lit by your headlights -- such as a backlit sign, or an address on a building, or something lit up with street lights -- will be unpolarized. That means regarless of which polarization angle your windshield is set to filter, half of the incident unpolarized light will be filtered as well (due to probabiliy, half of it will be polarized opposite your filter, regardless of orientation).


----------



## Gryloc (May 8, 2007)

You know, I had the idea of having a hexagonal or octagonal copper post that had an array of LED dies soldered or epoxied to each facet of the post and on each facet, there may be 3-4 rows of these. So, there are 3-4 on each facet and 6 or 8 facets on the post, that means a combination of 18, 24, or 32 dies in the compact cluster. You can use Cree's EX1000 die (used on the Cree XR-E, The Seoul P4, and the Edison -something-8) for an option of ~2700-4800 lumens of light, depending on number of dies and current levels (~150lm at 1A each when hot seems like a good figure, considering de-ratings). 

Here is an ancient thread I made a long time ago (using the old Luxeon Flash LED -crappy):
https://www.candlepowerforums.com/threads/107743
You have to scroll down a bit to see the picture I drew up pixel by pixel in PSP8.

Here is a more modern design using my own brew of XR-E styled emitter (4 dies packed close on a ceramic substrate):
https://www.candlepowerforums.com/threads/148085
You have to scroll down slowly to see the emitter that I drew up in SolidWorks, then I assembled it onto a special copper slug/post. There are 4 of the 4-die emitters positioned radially.

I forgot to mention that either of these designs will be liquid cooled by using simple passages that pass through the center of the post. The old design has the passage bending in the middle, allowing both water connection nipples to be connected at the bottom. The passages can be finned to give more surface area and allow for better cooling.

Well, what I was getting at here, I thought that with the multiple dies on a single post, you can easily switch each one on and off, or just 3 or 4 off at a time using multiple channels. This will make wiring them difficult, but it can be done. The specialized, smart driver can switch each bank/channel on and off (or just dime), so the reflected image is not projected onto the oncoming driver. To detect the oncoming driver, a specialized CCD camera can sense the positions of each oncoming light source (from the oncoming driver), and then know how to switch or dim each bank/channel to reduce the brightness of the light that may hit that driver's eyes. The camera can be automatic so even in the daytime, it will sense oncoming traffic by sensing dramatic changes in color/brightness (from the car's paint or shape). Maybe, since doing this will be difficult, each car is fitted with a fron projected infrared beacon (pulsed at a special, pre-set frequency for the CCD camera to sense. 

Cameras, when mixed with the proper software, can already detect differences in color and brightness levels throughout a specially mapped grid. Even the simple Lego Mindstorm set with that special vision kit (few years old) has this mapping technology, even though it is very simple. If the CCD camera cannot be used, I am sure a simple infrared sensor with the right lens can pull off the same feat.

The reflector of this headlight will have to be specialized for the LED cluster (most optics companies should be able to make them nowadays). This way, the reflected image of each LED, LED bank/channel, or region in general can be predicted and then this data can be entered into the software that runs that multi-channel driver.

Does any of them make sense? This is so hard to explain. My brother thought it was a nifty idea if someone can pull it off. The technology is there! It is not an extremely difficult system, and it should not cost the price of the car or anything (kinda reasonable). Of course, this system will have an override switch for the driver, and a manual high-low switch (high-low regions easy do program -easier than single regions from the multi-channel function). 

The polarization idea is pretty novel, but it would be a tricky and finicky system, especially if you have to tell owners of old cars to either replace their windshield on their car or wear polarized glasses at night. Hmmm. I have a simple set of experimental polarized filters, but they seem to be greenish and they are kind of dark from the start (maybe old technology). Wasted energy would be an issue. Even multi-LED cluster with multi-specialized reflectors (all customized IMS-27 like) would work. Just switch on each LED differently, or tilt the whole thing...

Well, I will let you chew through my idea. I got to go (public computers are really restricting me on the CPF -no home PC :scowl: )....


-Tony


----------



## Sub_Umbra (May 8, 2007)

:


----------



## TorchBoy (May 8, 2007)

2xTrinity said:


> In the first case, the light from the filament or arc (HID) will be unpolarized, meaning half of it will be rejected by the filter.


Um, yes... Did I make it clear I was referring to the windscreen?


----------



## 270winchester (May 13, 2007)

I know people like HIDs a lot. But for automotive purposes, a set of good, bright Halogen lights still gives me the kicks. Most 55w bulbs are very capable, and most modern HID lights on cars are horizontally cut off(in most cases) so the increased output is diminished, at least somewhat.

I drive an older, utilitarian car(no need for an expensive car for college in an area sandwiched between Oakland and Richmond), but I have a set of aux. lights that do very well on dark roads and in the hills, and completely within spec of the vehicle code. total cost? 70 dollars for the lights a 2 dollars for the hardware. These things should be available to all cars, not those hideously wide-scattering "high" beams on small cars that offer no use other than blinding people close up, and cannot do squat for actual road illumination.

that and encourage people to use optics-type fog lights. nothing more hazaradous than free-scattering bright "fog" lights in a foggy situation.







yeah yeah, I know in California you are only allowed to turn on 4 lights at a time on public roads. this was taken on private property. :nana:


----------

