optics that can be used for a Low-Beam ??

[mds82]

This is only an idea, I'm not planning any projects yet.

Are there any optics out there can can be used for the cree xp-g or any other LED that can create a nice cutoff beam? I know all lighting in cars is supposed to be DOT Approved, but as long as there is a correct cutoff beam, and the lights are angled correctly, they it shouldn't be too much of a problem.

Basically i would be looking for something that has a beam pattern close to a HID projector system. I've looked and have never been able to find anything useful. Thanks.

 

[Alaric Darconville]

I know all lighting in cars is supposed to be DOT Approved, but as long as there is a correct cutoff beam, and the lights are angled correctly, they it shouldn't be too much of a problem.

The DOT does not approve anything. It works on the manufacturer certifying their lamps as compliant with FMVSS 108. Making your own headlight, be it halogen, HID, or LED is a lot harder than you might think. See more in this post.

This post describes a particular difficulty with LED headlights -- heat management and lens thawing.

 

[Hamilton Felix]

Aside from the illegality, it's quite a challenge to achieve a good low beam. You don't want to blind others, or yourself in fog. But you need even foreground coverage, decent reach in your lane and good illumination of roadside and ditch.

If it's of interest, the HID headlights I bought for my Crown Vic from Starr HID are projector type. They use some kind of internal shutter or movable bulb shield to create a clean and properly shaped low beam. When I hit high the shield/shutter goes away and I see "the rest of the beam."

If your project uses multiple LEDs I'd say your task is more difficult than designing my headlights that use a single light source.

 

[mds82]

Yes I was planning on using a few led's. I have made myself fog lights already using 6 xp-g LEDs, a mirror directly over them, and then a aspheric lens in front of that. There is a 100% perfect cutoff , however it does not project quite as far as I would like. They are being driven with a 3amp driver with 2 parallel strings of 3 series LEDs

 

[Hamilton Felix]

Sounds like you have it together. To me, low beam is a lot like fog but narrowed and reaching further. You still need to avoid that upward scatter of light. Of course, there's the increased range in your own lane and the further increased illumination to the right of the road.

With some experimenting, I think it's feasible. But that will not make it legal on public highways. Still and all, have fun.

 

[Diesel_Bomber]

Having a sharp cutoff isn't the whole story, you must have the correct distribution of light underneath that cutoff. What you are attempting will not be legal in the slightest for any kind of road going vehicle. There are already LED low beam headlamps on the market, Hamsar and Speaker come to mind.

 

[mds82]

I understand the legal issues, I'm not asking about that.... What I am asking about is if it is possible

 

[Alaric Darconville]

I understand the legal issues, I'm not asking about that.... What I am asking about is if it is possible

Because we're discussing automotive lighting, inevitably and invariably it comes down to legal issues. Read the posts I linked in my first reply, and you'll see that there is a variety of tests the lights must conform to, and a host of technical problems that the OEMs are throwing a ton of money at to resolve. Yes, car makers have made some real progress, but using materials and processes that are typically not available to an individual.

So, in a way, it is *possible*, but no, it's not really possible.

 

[mds82]

Ok nevermind.... I ask a question a don't get answer.

Mods, please close thread

 

[Random Guy]

I think that what everyone is saying it that, yes, it is possible, but you must be able a great amount of time, money, and learning to do it. The automotive companies are spending millions of dollars trying to do this. There are alot of things that go into designing a headlamp beam that are not immediately apparent. Unless you have a very specific application that you are trying to design for, it will be far easier and cheaper to just buy an already existing LED headlamp, that someone else has spend the hundreds of thousands of dollars and hundreds of man-hours on.